Sample records for zn zurn ot

  1. OTS NOTE

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilA group currentBradleyTableSelling7 AugustAFRICAN .METALS~ c3 Alexander941 OTS NOTE

  2. OTS NOTE

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilA group currentBradleyTableSelling7 AugustAFRICAN .METALS~ c3 Alexander941 OTS

  3. OTS NOTE

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilA group currentBradleyTableSelling7 AugustAFRICAN .METALS~ c3 Alexander941 OTS@

  4. OTS NOTE

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilA group currentBradleyTableSelling7 AugustAFRICAN .METALS~ c3 Alexander941 OTS@*

  5. OTS NOTE

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilA group currentBradleyTableSelling7 AugustAFRICAN .METALS~ c3 Alexander941 OTS@*5,

  6. Assessment of Research Quality Utrecht institute of Linguistics OTS (UiL OTS)

    E-Print Network [OSTI]

    Utrecht, Universiteit

    Assessment of Research Quality Utrecht institute of Linguistics OTS (UiL OTS) Faculty of Arts and the Humanities / Arts Utrecht University 1997 - 2004 October 2005 #12;Title: Assessment of Research Quality Utrecht institute of Linguistics OTS (UiL OTS) Faculty of Arts and the Humanities / Arts Utrecht

  7. A Rob otLaboratoryforTeachingArtiflcialIntelligence / Deepak Kumar

    E-Print Network [OSTI]

    Kumar, Deepak

    A Rob otLaboratoryforTeachingArtiflcialIntelligence / Deepak Kumar Department ofMathematics Bryn Ma tasks.Inthelaboratory,studentsbuildtheirown robots and programthem toaccomplishthetasks.By con thestudyofAI centersaroundhow besttoimplement thismappingfromperceptionstoactions.The robot perspective

  8. OmniTread OT-4 Serpentine Robot new Features and Experiments Johann Borenstein* and Malik Hansen

    E-Print Network [OSTI]

    Borenstein, Johann

    1 OmniTread OT-4 Serpentine Robot ­ new Features and Experiments Johann Borenstein* and Malik-of-freedom joints. The OT-4 can climb over obstacles that are much higher than the robot itself, propel itself of the OT-4. Keywords: OmniTread, Serpentine Robot, Snake Robot, Snakebot, Mobile Robot, Hyper

  9. The OmniTread OT-4 Serpentine Robot1 Design and Performance

    E-Print Network [OSTI]

    Borenstein, Johann

    The OmniTread OT-4 Serpentine Robot1 ­ Design and Performance Johann Borenstein*, Malik Hansen joints. The OT-4 can climb over obstacles that are much higher than the robot itself, propel itself@umich.edu, hansenm@umich.edu, aborrell@umich.edu ABSTRACT Serpentine robots are slender, multi-segmented vehicles

  10. Abstract --Recent human pharmacological fMRI studies suggest that oxytocin (OT) is a centrally-acting

    E-Print Network [OSTI]

    Dascalu, Sergiu

    Abstract -- Recent human pharmacological fMRI studies suggest that oxytocin (OT) is a centrally-acting neurotransmitter important in the development and expression of trusting relationships in men and women. OT of several key interacting brain regions affected by OT neurophysiology during social trust behavior

  11. The OmniTread OT-4 Serpentine Robot for Emergencies and Hazardous Environments

    E-Print Network [OSTI]

    Borenstein, Johann

    The OmniTread OT-4 Serpentine Robot for Emergencies and Hazardous Environments Johann Borenstein: johannb@umich.edu, hansenm@umich.edu, hunguyen@umich.edu Abstract ­ Serpentine robots are slender, multi- segmented vehicles designed to provide greater mobility than conventional wheeled or tracked robots

  12. Abstract--This paper describes the development and testing of control of the OmniTread OT-4 robot by the Seventh

    E-Print Network [OSTI]

    Borenstein, Johann

    Abstract--This paper describes the development and testing of control of the OmniTread OT-4 robot system developed in simulation was tested by controlling the real OT-4 robot in the laboratory. The performance of the real OT-4 robot under 7G control on stairs, parallel bars, a slalom course, and stairs

  13. Computer software design description for the Treated Effluent Disposal Facility (TEDF), Project L-045H, Operator Training Station (OTS)

    SciTech Connect (OSTI)

    Carter, R.L. Jr.

    1994-11-07T23:59:59.000Z

    The Treated Effluent Disposal Facility (TEDF) Operator Training Station (OTS) is a computer-based training tool designed to aid plant operations and engineering staff in familiarizing themselves with the TEDF Central Control System (CCS).

  14. OTS NOTE

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilA group currentBradleyTableSelling7 AugustAFRICAN .METALS~ c3 Alexander Williams

  15. OTS NOTE

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilA group currentBradleyTableSelling7 AugustAFRICAN .METALS~ c3 Alexander

  16. OTS NOTE

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilA group currentBradleyTableSelling7 AugustAFRICAN .METALS~ c3 Alexander941

  17. OTS NOTE

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilA group currentBradleyTableSelling7 AugustAFRICAN .METALS~ c3 Alexander9412, 1990

  18. OTS NOTF

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilA group currentBradleyTableSelling7 AugustAFRICAN .METALS~ c3 Alexander9412,

  19. OTS NOTE

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilA groupTuba City, Arizona, DisposalFourthN V O 1 8 7 +NewAugust 4, 1992 TO:

  20. OT SPECIFIED I OTHER AMENDMENT OF SOLICITATI ON/MODIFICATION OF CONTRACT

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for RenewableSpeeding accessSpeeding access toScientificScientific andandScientific andOT

  1. Solar energy system performance evaluation - final report for Honeywell OTS 45, Salt River Project, Phoenix, Arizona

    SciTech Connect (OSTI)

    Mathur, A K

    1983-09-01T23:59:59.000Z

    This report describes the operation and technical performance of the Solar Operational Test Site (OTS 45) at Salt River Project in Phoenix, Arizona, based on the analysis of data collected between April 1981 and March 31, 1982. The following topics are discussed: system description, performance assessment, operating energy, energy savings, system maintenance, and conclusions. The solar energy system at OTS 45 is a hydronic heating and cooling system consisting of 8208 square feet of liquid-cooled flat-plate collectors; a 2500-gallon thermal storage tank; two 25-ton capacity organic Rankine-cycle-engine-assisted water chillers; a forced-draft cooling tower; and associated piping, pumps, valves, controls and heat rejection equipment. The solar system has eight basic modes of operation and several combination modes. The system operation is controlled automatically by a Honeywell-designed microprocessor-based control system, which also provides diagnostics. Based on the instrumented test data monitored and collected during the 8 months of the Operational Test Period, the solar system collected 1143 MMBtu of thermal energy of the total incident solar energy of 3440 MMBtu and provided 241 MMBtu for cooling and 64 MMBtu for heating. The projected net annual electrical energy savings due to the solar system was approximately 40,000 kWh(e).

  2. Changes in Zn speciation during soil formation from Zn-rich Olivier Jacquat a

    E-Print Network [OSTI]

    -containing calcite (at site Dornach), Zn-containing goethite (Gurnigel) and Zn-containing goethite and sphalerite contained substantial amounts of Zn-containing goethite ($50%) stemming from the parent rock, smaller in recalcitrant extraction steps, confirming that Zn-HIV, Zn-containing kaolinite and Zn-containing goethite

  3. Optical properties of ZnO/ZnS and ZnO/ZnTe heterostructures for photovoltaic applications

    E-Print Network [OSTI]

    Schrier, Joshua; Demchenko, Denis O.; Wang, Lin-Wang; Alivisatos, A. Paul

    2008-01-01T23:59:59.000Z

    ZnTe heterostructures for photovoltaic applications Joshuatoo large for optimal photovoltaic e?ciency. By using band-nanowires can be used as photovoltaic devices with organic

  4. AVESTAR Center for operational excellence of clean energy plants and DYNSIM OTS / EyeSim ITS integration

    SciTech Connect (OSTI)

    Provost, G.

    2012-01-01T23:59:59.000Z

    This Power-Point presentation with notes starts with a brief overview of US energy challenging, particularly as regards power generation capacity and clean energy plant operations. It then goes on to present Advanced Virtual Energy Simulation Training And Research (AVESTAR{trademark}) beginning with a statement of its missions and goals, then moves to the subject of Integrated Gasification Combined Cycle (IGCC) with CO{sub 2} Capture, first providing a brief overview of the process, then moving on to Dynamic Simulator/Operator Training System (OTS) and 3D Virtual Immersive Training System (ITS). The presentation continues to describe AVESTAR center facilities, locations, and training systems and to look at future directions for virtual energy simulation.

  5. DUSTY EXPLOSIONS FROM DUSTY PROGENITORS: THE PHYSICS OF SN 2008S AND THE 2008 NGC 300-OT

    SciTech Connect (OSTI)

    Kochanek, C. S. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus OH 43210 (United States)

    2011-11-01T23:59:59.000Z

    SN 2008S and the 2008 NGC 300-OT were explosive transients of stars self-obscured by very dense, dusty stellar winds. An explosive transient with an unobserved shock breakout luminosity of order 10{sup 10} L{sub sun} is required to render the transients little obscured and visible in the optical at their peaks. Such a large breakout luminosity then implies that the progenitor stars were cool, red supergiants, most probably {approx}9 M{sub sun} extreme asymptotic giant branch stars. As the shocks generated by the explosions propagate outward through the dense wind, they produce a shock luminosity in soft X-rays that powers the long-lived luminosity of the transients. Unlike typical cases of transients exploding into a surrounding circumstellar medium, the progenitor winds in these systems are optically thick to soft X-rays, easily absorb radio emission, and rapidly reform dust destroyed by the peak luminosity of the transients. As a result, X-rays are absorbed by the gas and the energy is ultimately radiated by the reformed dust. Three years post-peak, both systems are still significantly more luminous than their progenitor stars, but they are again fully shrouded by the reformed dust and only visible in the mid-IR. The high luminosity and heavy obscuration may make it difficult to determine the survival of the progenitor stars for {approx}10 years. However, our model indicates that SN 2008S, but not the NGC 300-OT, should now be a detectable X-ray source. SN 2008S has a higher estimated shock velocity and a lower density wind, so the X-rays begin to escape at a much earlier phase.

  6. THE DIVERSITY OF MASSIVE STAR OUTBURSTS. I. OBSERVATIONS OF SN2009ip, UGC 2773 OT2009-1, AND THEIR PROGENITORS

    SciTech Connect (OSTI)

    Foley, Ryan J.; Berger, Edo; Challis, Peter J.; Soderberg, Alicia M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Fox, Ori [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904 (United States); Levesque, Emily M. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Dr., Honolulu, HI 96822 (United States); Ivans, Inese I. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Rhoads, James E., E-mail: rfoley@cfa.harvard.edu [School of Earth and Space Exploration, Arizona State University, P.O. Box 871404, Tempe, AZ 85287 (United States)

    2011-05-01T23:59:59.000Z

    Despite both being outbursts of luminous blue variables (LBVs), SN 2009ip and UGC 2773 OT2009-1 have very different progenitors, spectra, circumstellar environments, and possibly physical mechanisms that generated the outbursts. From pre-eruption Hubble Space Telescope images, we determine that SN 2009ip and UGC 2773 OT2009-1 have initial masses of {approx}> 60 and {approx}> 25 M{sub sun}, respectively. Optical spectroscopy shows that at peak, SN 2009ip had a 10,000 K photosphere and its spectrum was dominated by narrow H Balmer emission, similar to classical LBV giant outbursts, also known as 'supernova impostors'. The spectra of UGC 2773 OT2009-1, which also have narrow H{alpha} emission, are dominated by a forest of absorption lines, similar to an F-type supergiant. Blueshifted absorption lines corresponding to ejecta at a velocity of 2000-7000 km s{sup -1} are present in later spectra of SN 2009ip-an unprecedented observation for LBV outbursts, indicating that the event was the result of a supersonic explosion rather than a subsonic outburst. The velocity of the absorption lines increases between two epochs, suggesting that there were two explosions in rapid succession. A rapid fading and rebrightening event concurrent with the onset of the high-velocity absorption lines is consistent with the double-explosion model. A near-infrared excess is present in the spectra and photometry of UGC 2773 OT2009-1 that is consistent with {approx}2100 K dust emission. We compare the properties of these two events and place them in the context of other known massive star outbursts such as {eta} Car, NGC 300 OT2008-1, and SN 2008S. This qualitative analysis suggests that massive star outbursts have many physical differences that can manifest as the different observables seen in these two interesting objects.

  7. Local coordination of Zn in hydroxy-interlayered minerals and implications for Zn retention in soils

    E-Print Network [OSTI]

    -interlayered minerals (HIM) for Zn retention in contaminated soils. Published and newly collected extended XLocal coordination of Zn in hydroxy-interlayered minerals and implications for Zn retention. In a second part, we determined the spe- ciation of Zn in eight contaminated soils (2511039 mg/kg Zn

  8. PRECEDING F!_GE E_LA."jK _OT F:LP#,ED THE ROLES OF HUMANS AND ROBOTS AS

    E-Print Network [OSTI]

    Spudis, Paul D.

    307 PRECEDING F!_GE E_LA."jK _OT F:LP#,ED THE ROLES OF HUMANS AND ROBOTS AS FIELD GEOLOGISTS field study on the Moon is through the use of teleoperated robots, under the da'rect control of a human geologist who remains at the lunar base, or poss_ly on Earth. These robots umuld hate a global traverse

  9. ZnO/Sn:In2O3 and ZnO/CdTe band offsets for extremely thin absorber...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ZnOSn:In2O3 and ZnOCdTe band offsets for extremely thin absorber photovoltaics . ZnOSn:In2O3 and ZnOCdTe band offsets for extremely thin absorber photovoltaics . Abstract: Band...

  10. Toward ZnO Light Emitting Diode

    E-Print Network [OSTI]

    Liu, Jianlin

    2008-01-01T23:59:59.000Z

    applications such as light emitting diodes (LEDs) and laser009 "Toward ZnO Light Emitting Diode" Jianlin Liu July 2008Title: Toward ZnO Light Emitting Diode Sponsor: UC Energy

  11. Structural and magnetic properties of NiZn and Zn ferrite thin films obtained by laser ablation deposition

    E-Print Network [OSTI]

    McHenry, Michael E.

    Structural and magnetic properties of NiZn and Zn ferrite thin films obtained by laser ablation ferrite structures. Our investigations were performed on NiZn and Zn ferrite films deposited on silicon of the blocking temperature in both NiZn and Zn ferrite systems. © 2005 American Institute of Physics. DOI: 10

  12. Structural, optical and magnetic properties of ZnOFe/ZnO multilayers

    SciTech Connect (OSTI)

    Nakayama, H.; Kinoshita, R.; Sakamoto, I. [Hosei University, Koganei, Tokyo 184-8584 (Japan); Yasumoto, M.; Koike, M. [National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568 (Japan); Honda, S. [Shimane University, Matsue, Shimane 690-8504 (Japan)

    2013-12-04T23:59:59.000Z

    ZnOFe/ZnO multilayers (MLs) with the constant composition and the different thickness in ZnOFe layers have been prepared by helicon plasma sputtering. The XRD patterns of ZnOFe/ZnO MLs before annealing showed only ZnO diffraction peaks while one after annealing indicated the phases of ZnO and ZnFe{sub 2}O{sub 4}. The magnetization curves of ZnOFe/ZnO MLs before and after annealing showed ferromagnetic behavior. The origin of ferromagnetism in ZnOFe/ZnO MLs before annealing is considered to be due to the formation of defects/vacancies resulting from the substitution of Fe{sup 3+} ions for Zn{sub 2+} ions in ZnOFe layers irrespective of the mixed Fe valence states seen in XANES spectra. The ferromagnetic behavior after annealing is due to the formation of ZnFe{sub 2}O{sub 4}, which was confirmed by XRD, XPS, RBS measurements.

  13. Ultraviolet emission from a multi-layer graphene/MgZnO/ZnO light-emitting diode

    SciTech Connect (OSTI)

    Kang, Jang-Won; Choi, Yong-Seok; Goo Kang, Chang; Hun Lee, Byoung [School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of); Kim, Byeong-Hyeok [Department of Nanobio Materials and Electronics, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of); Tu, C. W. [Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093-0407 (United States); Park, Seong-Ju, E-mail: sjpark@gist.ac.kr [School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of); Department of Nanobio Materials and Electronics, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of)

    2014-02-03T23:59:59.000Z

    We report on ultraviolet emission from a multi-layer graphene (MLG)/MgZnO/ZnO light-emitting diodes (LED). The p-type MLG and MgZnO in the MLG/MgZnO/ZnO LED are used as transparent hole injection and electron blocking layers, respectively. The current-voltage characteristics of the MLG/MgZnO/ZnO LED show that current transport is dominated by tunneling processes in the MgZnO barrier layer under forward bias conditions. The holes injected from p-type MLG recombine efficiently with the electrons accumulated in ZnO, and the MLG/MgZnO/ZnO LED shows strong ultraviolet emission from the band edge of ZnO and weak red-orange emission from the deep levels of ZnO.

  14. ZnS/Zn(O,OH)S-based buffer layer deposition for solar cells

    DOE Patents [OSTI]

    Bhattacharya, Raghu N. (Littleton, CO)

    2009-11-03T23:59:59.000Z

    The invention provides CBD ZnS/Zn(O,OH)S and spray deposited ZnS/Zn(O,OH)S buffer layers prepared from a solution of zinc salt, thiourea and ammonium hydroxide dissolved in a non-aqueous/aqueous solvent mixture or in 100% non-aqueous solvent. Non-aqueous solvents useful in the invention include methanol, isopropanol and triethyl-amine. One-step deposition procedures are described for CIS, CIGS and other solar cell devices.

  15. Interaction of CO with Surface PdZn Alloys. | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    with Surface PdZn Alloys. Interaction of CO with Surface PdZn Alloys. Abstract: The adsorption and bonding configuration of CO on clean and Zn-covered Pd(111) surfaces was studied...

  16. Aggregation, Coarsening, and Phase Transformation in ZnSNanoparticles...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Coarsening, and Phase Transformation in ZnS NanoparticlesStudied by Molecular Dynamics Simulations. Aggregation, Coarsening, and Phase Transformation in ZnS...

  17. Studies on intrinsic defects related to Zn vacancy in ZnO nanoparticles

    SciTech Connect (OSTI)

    Singh, V.P. [School of Materials Science and Technology, Indian Institute of Technology (BHU), Varanasi, 221005 (India)] [School of Materials Science and Technology, Indian Institute of Technology (BHU), Varanasi, 221005 (India); Das, D. [UGC-DAE Consortium for Scientific Research, Kolkata Centre (India)] [UGC-DAE Consortium for Scientific Research, Kolkata Centre (India); Rath, Chandana, E-mail: chandanarath@yahoo.com [School of Materials Science and Technology, Indian Institute of Technology (BHU), Varanasi, 221005 (India)] [School of Materials Science and Technology, Indian Institute of Technology (BHU), Varanasi, 221005 (India)

    2013-02-15T23:59:59.000Z

    Graphical abstract: Display Omitted Highlights: ? WilliamsonHall analysis of ZnO indicates strain in the lattice and size is of 20 nm. ? PL shows a broad emission peak in visible range due to native defects. ? Raman active modes corresponding to P6{sub 3}mc and a few additional modes are observed. ? FTIR detects few local vibrational modes of hydrogen attached to zinc vacancies. ? V{sub Zn}-H and Zn + O divacancies are confirmed by PAS. -- Abstract: ZnO being a well known optoelectronic semiconductor, investigations related to the defects are very promising. In this report, we have attempted to detect the defects in ZnO nanoparticles synthesized by the conventional coprecipitation route using various spectroscopic techniques. The broad emission peak observed in photoluminescence spectrum and the non zero slope in WilliamsonHall analysis indicate the defects induced strain in the ZnO lattice. A few additional modes observed in Raman spectrum could be due to the breakdown of the translation symmetry of the lattice caused by defects and/or impurities. The presence of impurities can be ruled out as XRD pattern shows pure wurtzite structure. The presence of the vibrational band related to the Zn vacancies (V{sub Zn}), unintentional hydrogen dopants and their complex defects confirm the defects in ZnO lattice. Positron life time components ?{sub 1} and ?{sub 2} additionally support V{sub Zn} attached to hydrogen and to a cluster of Zn and O di-vacancies respectively.

  18. transporters and Zn2+ homeostasis in neurons

    E-Print Network [OSTI]

    Laskowski, Dustin Thomas Program in Neuroscience, Department of Biological Sciences, Ohio University, Athens, this review presents a working model of neuronal Zn2 + homeostasis and discusses the experimental evidence). Similar symptoms are seen in humans suffering from various causes of Zn2 + deficiency (Prasad, 1997

  19. Reactive ZnO/Ti/ZnO interfaces studied by hard x-ray photoelectron spectroscopy

    SciTech Connect (OSTI)

    Knut, Ronny, E-mail: Ronny.Knut@physics.gu.se; Lindblad, Rebecka; Rensmo, Hkan; Karis, Olof [Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala (Sweden); Grachev, Sergey; Faou, Jean-Yvon; Sndergrd, Elin [Unit Mixte CNRS/Sain-Gobain Recherche, 39 Quai Lucien Lefranc, 93303 Aubervilliers (France); Gorgoi, Mihaela [Helmholtz-Zentrum Berlin fr Materialien und Energie, Albert-Einstein-Str. 15, D-12489 Berlin (Germany)

    2014-01-28T23:59:59.000Z

    The chemistry and intermixing at buried interfaces in sputter deposited ZnO/Ti/ZnO thin layers were studied by hard x-ray photoelectron spectroscopy. The long mean free path of the photoelectrons allowed for detailed studies of the oxidation state, band bending effects, and intrinsic doping of the buried interfaces. Oxidation of the Ti layer was observed when ZnO was deposited on top. When Ti is deposited onto ZnO, Zn Auger peaks acquire a metallic character indicating a strong reduction of ZnO at the interface. Annealing of the stack at 200?C results in further reduction of ZnO and oxidation of Ti. Above 300?C, oxygen transport from the bulk of the ZnO layer takes place, leading to re-oxidation of ZnO at the interface and further oxidation of Ti layer. Heating above 500?C leads to an intermixing of the layers and the formation of a Zn{sub x}TiO{sub y} compound.

  20. GaN/ZnO and AlGaN/ZnO heterostructure LEDs: growth, fabrication, optical and electrical characterization

    E-Print Network [OSTI]

    Wetzel, Christian M.

    GaN/ZnO and AlGaN/ZnO heterostructure LEDs: growth, fabrication, optical and electrical 12180-3590, U.S.A. ABSTRACT The wide bandgap polar semiconductors GaN and ZnO and their related alloys fields, and surface terminations. With a small lattice mismatch of ~1.8 % between GaN and Zn

  1. Appearance of infused zinc ( sup 70 Zn) and oral zinc ( sup 68 Zn) in breast milk

    SciTech Connect (OSTI)

    Moser-Veillon, P.B.; Patterson, K.Y.; Mangels, A.R.; Wallace, G.F.; Veillon, C. (Univ. of Maryland, College Park (United States) Dept. of Agriculture, Beltsville, MD (United States) Perkin-Elmer Corp., Rockville, MD (United States))

    1991-03-15T23:59:59.000Z

    The purpose of this study was to monitor the appearance of a simultaneous intravenous (IV) dose and oral dose of stable isotopes, {sup 70}Zn and {sup 68}Zn, respectively, in breast milk. Three lactating subjects, 2-3 months postpartum were fed a controlled diet which contained an average of 7.8 mg Zn/day. Subjects collected milk samples at the beginning of each feeding for a 24 hour period on the fifth day of the controlled diet. On day 7 of the controlled diet, a 160 ug IV dose of {sup 70}Zn as zinc chloride in saline was infused into each subject. The subjects also received 2 mg of {sup 68 }Zn as zinc chloride in 50 ml of orange juice. Following the stable isotope doses, subjects collected milk samples at the beginning of each feeding for 48 hours, weighing their infants before and after each feeding. The amount of natural Zn, {sup 70}Zn and {sup 68}Zn tracers in the milk was measured by isotope dilution mass spectrometry. The cumulative {sup 70}Zn excretion into breast milk over 48 hours was approximately 1% of the infused dose and the cumulative {sup 68}Zn excretion was smaller still. Thus, only a small fraction of a physiological IV or oral dose of zinc comes out in the milk. The small fraction of {sup 70}Zn and {sup 68}Zn appearing in the milk suggests that circulating zinc and dietary zinc are not rapidly or directly incorporated into breast milk in appreciable amounts.

  2. An electrostatic nanogenerator based on ZnO/ZnS core/shell electrets with stabilized quasi-permanent charge

    SciTech Connect (OSTI)

    Wang, Chao; Cai, Liang; Feng, Yajuan; Chen, Lin; Yan, Wensheng, E-mail: ywsh2000@ustc.edu.cn, E-mail: zhsun@ustc.edu.cn; Liu, Qinghua; Yao, Tao; Hu, Fengchun; Pan, Zhiyun; Sun, Zhihu, E-mail: ywsh2000@ustc.edu.cn, E-mail: zhsun@ustc.edu.cn; Wei, Shiqiang [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029 (China)

    2014-06-16T23:59:59.000Z

    ZnO-based nanogenerators with excellent performance and convenient functionalization are particularly desirable for self-powered technology, which is however difficult to achieve simultaneously in traditional piezoelectric ZnO nanogenerators. Here, we report a design of electrostatic ZnO nanogenerator by virtue of a type-II ZnO/ZnS core/shell nanostructure electrets, which can turn acoustic waves into electric power with an energy conversion efficiency of 2.2%. The ZnO/ZnS core/shell electrets are charged by ultraviolet irradiation with a long-term stability of the electrostatic charges under ambient condition. The electronic and atomic structure evolution in the charged ZnO/ZnS core/shell electrets are also discussed by detailed experimental and theoretical investigations. This design opens up an alternative path for fabricating robust ZnO-based nanogenerator for future nanotechnology application.

  3. 891070-9932/142014IEEE sEptEmbEr 2014 IEEE rObOtICs & AUtOmAtION mAGAZINE By Yaroslav Tenzer, Leif P. Jentoft, and Robert D. Howe

    E-Print Network [OSTI]

    891070-9932/14©2014IEEE sEptEmbEr 2014 · IEEE rObOtICs & AUtOmAtION mAGAZINE · The Feel of MEMS available for a wide range of robotics and human-interface applications. Background Tactile sensing, such as the location of object contacts on the robot hand and contact pressure distribution, are believed

  4. Novel Stabilization Mechanism on Polar Surfaces: ZnO(0001)-Zn Olga Dulub,1

    E-Print Network [OSTI]

    Diebold, Ulrike

    r Materialphysik and Centre for Computational Materials Science, Universitat Wien, A-1090 Wien, Austria (Received identification of the stabilization mechanisms of polar ZnO surfaces and the resulting surface properties would will cancel the polarity. If the Zn-terminated surface is less positive and the O-terminated surface layer

  5. Cyclotron production of {sup 61}Cu using natural Zn and enriched {sup 64}Zn targets

    SciTech Connect (OSTI)

    Asad, A. H.; Smith, S. V.; Chan, S.; Jeffery, C. M.; Morandeau, L.; Price, R. I. [RAPID PET Labs, Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth, Australia, Imaging and Applied Physics, Curtin University, Perth, Australia, and Center of Excellence in Anti-matter Matter Studies, Australian National University, Can (Australia); Brookhaven National Laboratory, Upton, NY (United States) and Center of Excellence in Anti-matter Matter Studies, Australian National University, Canberra (Australia); RAPID PET Labs, Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth (Australia); RAPID PET Labs, Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth (Australia); Center of Excellence in Anti-matter Matter Studies, Australian National University, Canberra, Australia, and Chemistry, University of Western Australia, Pe (Australia); RAPID PET Labs, Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth (Australia); RAPID PET Labs, Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth, Australia and Physics, University of Western Australia, Perth (Australia)

    2012-12-19T23:59:59.000Z

    Copper-61 ({sup 61}Cu) shares with {sup 64}Cu certain advantages for PET diagnostic imaging, but has a shorter half-life (3.4hr vs. 12.7hr) and a greater probability of positron production per disintegration (61% vs. 17.9%). One important application is for in vivo imaging of hypoxic tissue. In this study {sup 61}Cu was produced using the {sup 64}Zn(p,{alpha}){sup 61}Cu reaction on natural Zn or enriched {sup 64}Zn targets. The enriched {sup 64}Zn (99.82%) was electroplated onto high purity gold or silver foils or onto thin Al discs. A typical target bombardment used 30{mu}A; at 11.7, 14.5 or 17.6MeV over 30-60min. The {sup 61}Cu (radiochemical purity of >95%) was separated using a combination of cation and anion exchange columns. The {sup 64}Zn target material was recovered after each run, for re-use. In a direct comparison with enriched {sup 64}Zn-target results, {sup 61}Cu production using the cheaper {sup nat}Zn target proved to be an effective alternative.

  6. DOI : 10. 1051/jp4 :20030389 Zn speciation in

    E-Print Network [OSTI]

    smelter in Northem France ( [Zn] = 6600 and as a 40 cm thick layer on a agricultural soil in 1997. zen

  7. Formation of Zn-rich phyllosilicate, Zn-layered double hydroxide and hydrozincite in contaminated calcareous soils

    E-Print Network [OSTI]

    Jacquat, Olivier

    2009-01-01T23:59:59.000Z

    Zn/Al hydrotalcite in smelter-impacted soils from northernQuantitative Zn speciation in smelter-contaminated soils byand bioavailability of zinc in a smelter contaminated soil.

  8. Electroluminescence of ZnO-based semiconductor heterostructures

    SciTech Connect (OSTI)

    Novodvorskii, O A; Lotin, A A; Panchenko, Vladislav Ya; Parshina, L S; Khaidukov, E V; Zuev, D A; Khramova, O D [Institute on Laser and Information Technologies, Russian Academy of Sciences, Shatura, Moscow Region (Russian Federation)

    2011-01-31T23:59:59.000Z

    Using pulsed laser deposition, we have grown n-ZnO/p-GaN, n-ZnO/i-ZnO/p-GaN and n-ZnO/n-Mg{sub 0.2}Zn{sub 0.8}O/i-Cd{sub 0.2}Zn{sub 0.8}O/p-GaN light-emitting diode (LED) heterostructures with peak emission wavelengths of 495, 382 and 465 nm and threshold current densities (used in electroluminescence measurements) of 1.35, 2, and 0.48 A cm{sup -2}, respectively. Because of the spatial carrier confinement, the n-ZnO/n-Mg{sub 0.2}Zn{sub 0.8}O/i-Cd{sub 0.2}Zn{sub 0.8}O/p-GaN double heterostructure LED offers a higher electroluminescence intensity and lower electroluminescence threshold in comparison with the n-ZnO/p-GaN and n-ZnO/i-ZnO/p-GaN LEDs. (lasers)

  9. Study of stability of ZnO nanoparticles and growth mechanisms of colloidal ZnO nanorods

    E-Print Network [OSTI]

    Lee, Kwang Jik

    2006-10-30T23:59:59.000Z

    After hydrolyzing zinc acetate in methanol solution, spherical ZnO nanoparticles in the size range from about 2.5 to 5 nm were synthesized by maintaining a ZnO concentration of 0.02M. Compared to ZnO nanoparticles prepared ...

  10. Green emission in carbon doped ZnO films

    SciTech Connect (OSTI)

    Tseng, L. T.; Yi, J. B., E-mail: jiabao.yi@unsw.edu.au; Zhang, X. Y.; Xing, G. Z.; Luo, X.; Li, S. [School of Materials Science and Engineering, University of New South Wales, Kensington, NSW, 2052 (Australia); Fan, H. M. [School of Chemical Engineering, Northwest University, Xi'an 710069 (China); Herng, T. S.; Ding, J. [Department of Materials Science and Engineering, National University of Singapore, 119260 (Singapore); Ionescu, M. [Australian Nuclear Science and Technology Organization, (ANSTO), New Illawarra Road, Lucas Heights, NSW 2234 (Australia)

    2014-06-15T23:59:59.000Z

    The emission behavior of C-doped ZnO films, which were prepared by implantation of carbon into ZnO films, is investigated. Orange/red emission is observed for the films with the thickness of 60100 nm. However, the film with thickness of 200 nm shows strong green emission. Further investigations by annealing bulk ZnO single crystals under different environments, i.e. Ar, Zn or C vapor, indicated that the complex defects based on Zn interstitials are responsible for the strong green emission. The existence of complex defects was confirmed by electron spin resonance (ESR) and low temperature photoluminescence (PL) measurement.

  11. Twinning effect on photoluminescence spectra of ZnSe nanowires

    SciTech Connect (OSTI)

    Xu, Jing; Wang, Chunrui, E-mail: crwang@dhu.edu.cn; Wu, Binhe; Xu, Xiaofeng [Department of Applied Physics and State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, 2999 Renmin Rd. North, Songjiang District, Shanghai 201620 (China); Chen, Xiaoshuang [Department of Applied Physics and State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, 2999 Renmin Rd. North, Songjiang District, Shanghai 201620 (China); National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Science, Shanghai 200083 (China); Oh, Hongseok; Baek, Hyeonjun; Yi, Gyu-Chul [Department of Physics and Astronomy, Seoul National University, 599 Gwanak-ro, Gwanak-gu, Seoul 151-747 (Korea, Republic of)

    2014-11-07T23:59:59.000Z

    Bandgap engineering in a single material along the axial length of nanowires may be realized by arranging periodic twinning, whose twin plane is vertical to the axial length of nanowires. In this paper, we report the effect of twin on photoluminescence of ZnSe nanowires, which refers to the bandgap of it. The exciton-related emission peaks of transverse twinning ZnSe nanowires manifest a 10-meV-blue-shift in comparison with those of longitudinal twinning ZnSe nanowires. The blue-shift is attributed to quantum confinement effect, which is influenced severely by the proportion of wurtzite ZnSe layers in ZnSe nanowires.

  12. Thermoelectric properties of ZnSb films grown by MOCVD

    SciTech Connect (OSTI)

    Venkatasubramanian, R.; Watko, E.; Colpitts, T.

    1997-07-01T23:59:59.000Z

    The thermoelectric properties of ZnSb films grown by metallorganic chemical vapor deposition (MOCVD) are reported. The growth conditions necessary to obtain stoichiometric ZnSb films and the effects of various growth parameters on the electrical conductivity and Seebeck coefficients of the films are described. The as-grown ZnSb films are p-type. It was observed that the thicker ZnSb films offer improved carrier mobilities and lower free-carrier concentration levels. The Seebeck coefficient of ZnSb films was found to rise rapidly at approximately 160 C. The thicker films, due to the lower doping levels, indicate higher Seebeck coefficients between 25 to 200 C. A short annealing of the ZnSb film at temperatures of {approximately}200 C results in reduced free-carrier level. Thermal conductivity measurements of ZnSb films using the 3-{omega} method are also presented.

  13. OTS NOTE DATE: TO: FROM:

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilA group currentBradleyTableSelling7 AugustAFRICAN .METALS~ c3 Alexander9412, 1990

  14. Defect induced ferromagnetism in undoped ZnO nanoparticles

    SciTech Connect (OSTI)

    Rainey, K.; Chess, J.; Eixenberger, J.; Tenne, D. A.; Hanna, C. B.; Punnoose, A., E-mail: apunnoos@boisestate.edu [Department of Physics, Boise State University, Boise, Idaho 83725 (United States)

    2014-05-07T23:59:59.000Z

    Undoped ZnO nanoparticles (NPs) with size ?12?nm were produced using forced hydrolysis methods using diethylene glycol (DEG) [called ZnO-I] or denatured ethanol [called ZnO-II] as the reaction solvent; both using Zn acetate dehydrate as precursor. Both samples showed weak ferromagnetic behavior at 300?K with saturation magnetization M{sub s}?=?0.077 0.002 memu/g and 0.088 0.013 memu/g for ZnO-I and ZnO-II samples, respectively. Fourier transform infrared (FTIR) spectra showed that ZnO-I nanocrystals had DEG fragments linked to their surface. Photoluminescence (PL) data showed a broad emission near 500?nm for ZnO-II which is absent in the ZnO-I samples, presumably due to the blocking of surface traps by the capping molecules. Intentional oxygen vacancies created in the ZnO-I NPs by annealing at 450?C in flowing Ar gas gradually increased M{sub s} up to 90?min and x-ray photoelectron spectra (XPS) suggested that oxygen vacancies may have a key role in the observed changes in M{sub s}. Finally, PL spectra of ZnO showed the appearance of a blue/violet emission, attributed to Zn interstitials, whose intensity changes with annealing time, similar to the trend seen for M{sub s}. The observed variation in the magnetization of ZnO NP with increasing Ar annealing time seems to depend on the changes in the number of Zn interstitials and oxygen vacancies.

  15. Spin noise spectroscopy of ZnO

    SciTech Connect (OSTI)

    Horn, H.; Berski, F.; Hbner, J.; Oestreich, M. [Institute for Solid State Physics, Leibniz Universitt Hannover, Appelstr. 2, 30167 Hannover (Germany); Balocchi, A.; Marie, X. [INSA-CNRS-UPS, LPCNO, Universit de Toulouse, 135 Av. de Rangueil, 31077 Toulouse (France); Mansur-Al-Suleiman, M.; Bakin, A.; Waag, A. [Institute of Semiconductor Technology, Technische Universitt Braunschweig, Hans-Sommer-Strae 66, 38106 Braunschweig (Germany)

    2013-12-04T23:59:59.000Z

    We investigate the thermal equilibrium dynamics of electron spins bound to donors in nanoporous ZnO by optical spin noise spectroscopy. The spin noise spectra reveal two noise contributions: A weak spin noise signal from undisturbed localized donor electrons with a dephasing time of 24 ns due to hyperfine interaction and a strong spin noise signal with a spin dephasing time of 5 ns which we attribute to localized donor electrons which interact with lattice defects.

  16. Compared Raman study of the phase transitions in K2ZnCl4 and Rb2ZnCl4, Rb2ZnBr4, K2SeO4

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    787 Compared Raman study of the phase transitions in K2ZnCl4 and Rb2ZnCl4, Rb2ZnBr4, K2SeO4 M to the incommensurate phase is discussed for the four compounds K2SeO4, K2ZnCl4, Rb2ZnCl4 and Rb2ZnBr4 on the basis measurements on K2ZnC'4 known to exhibit successive phase transitions similar to those of K2SeO4

  17. Controllable Template Synthesis of Superconducting Zn Nanowires with

    E-Print Network [OSTI]

    June 9, 2005 ABSTRACT A systematic study was conducted on the fabrication, structural characterization by electrodepositing Zn into commercially available polycarbonate (PC) or anodic aluminum oxide (AAO) membranes

  18. Built-in electric field in ZnO based semipolar quantum wells grown on (1012) ZnO substrates

    SciTech Connect (OSTI)

    Chauveau, J.-M.; Xia, Y.; Roland, B.; Vinter, B. [Centre de Recherche sur l'Htro-Epitaxie et ses Applications, Centre National de la Recherche Scientifique (CRHEA-CNRS), Rue B. Gregory, F-06560 Valbonne Sophia Antipolis (France) [Centre de Recherche sur l'Htro-Epitaxie et ses Applications, Centre National de la Recherche Scientifique (CRHEA-CNRS), Rue B. Gregory, F-06560 Valbonne Sophia Antipolis (France); University of Nice Sophia Antipolis, Parc Valrose, F-06102 Nice Cedex 2 (France); Ben Taazaet-Belgacem, I.; Teisseire, M.; Nemoz, M.; Brault, J.; Damilano, B.; Leroux, M. [Centre de Recherche sur l'Htro-Epitaxie et ses Applications, Centre National de la Recherche Scientifique (CRHEA-CNRS), Rue B. Gregory, F-06560 Valbonne Sophia Antipolis (France)] [Centre de Recherche sur l'Htro-Epitaxie et ses Applications, Centre National de la Recherche Scientifique (CRHEA-CNRS), Rue B. Gregory, F-06560 Valbonne Sophia Antipolis (France)

    2013-12-23T23:59:59.000Z

    We report on the properties of semipolar (Zn,Mg)O/ZnO quantum wells homoepitaxially grown by molecular beam epitaxy on (1012) R-plane ZnO substrates. We demonstrate that atomically flat interfaces can be achieved with fully relaxed quantum wells because the mismatch between (Zn,Mg)O and ZnO is minimal for this growth orientation. The photoluminescence properties evidence a quantum confined Stark effect with an internal electric field estimated to 430 kV/cm for a 17% Mg content in the barriers. The quantum well emission is strongly polarized along the 1210 direction and a comparison with the semipolar bulk ZnO luminescence polarization points to the effect of the confinement.

  19. Formation of Zn-rich phyllosilicate, Zn-layered double hydroxide and hydrozincite in contaminated calcareous soils

    E-Print Network [OSTI]

    Jacquat, Olivier

    2009-01-01T23:59:59.000Z

    soil thin section and corresponding -XRF maps (black: lowestsection and corresponding - XRF maps for Zn, Ca, Fe and Mn (soil thin section and corresponding -XRF maps (black: lowest

  20. Indentation creep study on ultrafine-grained Zn processed by powder metallurgy

    E-Print Network [OSTI]

    Gubicza, Jen

    t Ultrafine-grained Zn (UFG-Zn) with the grain size of about 200 nm was processed by Spark Plasma Sintering

  1. Organic Molecule Functionalized Zn3P2 Nanowire Inorganic-Organic...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Molecule Functionalized Zn3P2 Nanowire Inorganic-Organic Hybrid Thermoelectrics Organic Molecule Functionalized Zn3P2 Nanowire Inorganic-Organic Hybrid Thermoelectrics Demonstrates...

  2. Benefits of homoepitaxy on the properties of nonpolar (Zn,Mg)O/ZnO quantum wells on a-plane ZnO substrates

    SciTech Connect (OSTI)

    Chauveau, J.-M.; Vinter, B. [Centre de Recherche sur l'Hetero-Epitaxie et ses Applications (CRHEA), Centre National de la Recherche Scientifique (CNRS), Rue B. Gregory, F-06560 Valbonne Sophia Antipolis (France); University of Nice Sophia Antipolis, Parc Valrose, F-06102 Nice Cedex 2 (France); Teisseire, M.; Kim-Chauveau, H.; Deparis, C.; Morhain, C. [Centre de Recherche sur l'Hetero-Epitaxie et ses Applications (CRHEA), Centre National de la Recherche Scientifique (CNRS), Rue B. Gregory, F-06560 Valbonne Sophia Antipolis (France)

    2010-08-23T23:59:59.000Z

    We report on the properties of nonpolar (Zn,Mg)O/ZnO quantum wells (QW) homoepitaxially grown by molecular beam epitaxy on a-plane ZnO substrates. We demonstrate a drastic improvement of the structural properties. We compare the photoluminescence properties of nonpolar homoepitaxial QWs and nonpolar heteroepitaxial QWs grown on sapphire and show that the reduction in structural defects and the improvement of surface morphology are correlated with a strong enhancement of the photoluminescence properties: reduction in full width at half maximum, strong increase in the luminescence intensities and their thermal stability. The comparison convincingly demonstrates the interest of homoepitaxial nonpolar QWs for bright UV emission applications.

  3. Neutral nitrogen acceptors in ZnO: The {sup 67}Zn hyperfine interactions

    SciTech Connect (OSTI)

    Golden, E. M.; Giles, N. C., E-mail: Nancy.Giles@afit.edu [Department of Engineering Physics, Air Force Institute of Technology, Wright-Patterson Air Force Base, Ohio 45433 (United States); Evans, S. M.; Halliburton, L. E. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506 (United States)

    2014-03-14T23:59:59.000Z

    Electron paramagnetic resonance (EPR) is used to characterize the {sup 67}Zn hyperfine interactions associated with neutral nitrogen acceptors in zinc oxide. Data are obtained from an n-type bulk crystal grown by the seeded chemical vapor transport method. Singly ionized nitrogen acceptors (N{sup ?}) initially present in the crystal are converted to their paramagnetic neutral charge state (N{sup 0}) during exposure at low temperature to 442 or 633?nm laser light. The EPR signals from these N{sup 0} acceptors are best observed near 5?K. Nitrogen substitutes for oxygen ions and has four nearest-neighbor cations. The zinc ion along the [0001] direction is referred to as an axial neighbor and the three equivalent zinc ions in the basal plane are referred to as nonaxial neighbors. For axial neighbors, the {sup 67}Zn hyperfine parameters are A{sub ?}?=?37.0?MHz and A{sub ?}?=?8.4?MHz with the unique direction being [0001]. For nonaxial neighbors, the {sup 67}Zn parameters are A{sub 1}?=?14.5?MHz, A{sub 2}?=?18.3?MHz, and A{sub 3}?=?20.5?MHz with A{sub 3} along a [101{sup }0] direction (i.e., in the basal plane toward the nitrogen) and A{sub 2} along the [0001] direction. These {sup 67}Zn results and the related {sup 14}N hyperfine parameters provide information about the distribution of unpaired spin density at substitutional neutral nitrogen acceptors in ZnO.

  4. SrZn{sub 2}Sn{sub 2} and Ca{sub 2}Zn{sub 3}Sn{sub 6} - two new Ae-Zn-Sn polar intermetallic compounds (Ae: alkaline earth metal)

    SciTech Connect (OSTI)

    Stegmaier, Saskia [Department Chemie, Technische Universitaet Muenchen, Lichtenbergstrasse 4, 85747 Garching (Germany); Faessler, Thomas F., E-mail: Thomas.Faessler@lrz.tum.de [Department Chemie, Technische Universitaet Muenchen, Lichtenbergstrasse 4, 85747 Garching (Germany)

    2012-08-15T23:59:59.000Z

    SrZn{sub 2}Sn{sub 2} and Ca{sub 2}Zn{sub 3}Sn{sub 6}, two closely related new polar intermetallic compounds, were obtained by high temperature reactions of the elements. Their crystal structures were determined with single crystal XRD methods, and their electronic structures were analyzed by means of DFT calculations. The Zn-Sn structure part of SrZn{sub 2}Sn{sub 2} comprises (anti-)PbO-like {l_brace}ZnSn{sub 4/4}{r_brace} and {l_brace}SnZn{sub 4/4}{r_brace} layers. Ca{sub 2}Zn{sub 3}Sn{sub 6} shows similar {l_brace}ZnSn{sub 4/4}{r_brace} layers and {l_brace}Sn{sub 4}Zn{r_brace} slabs constructed of a covalently bonded Sn scaffold capped by Zn atoms. For both phases, the two types of layers are alternatingly stacked and interconnected via Zn-Sn bonds. SrZn{sub 2}Sn{sub 2} adopts the SrPd{sub 2}Bi{sub 2} structure type, and Ca{sub 2}Zn{sub 3}Sn{sub 6} is isotypic to the R{sub 2}Zn{sub 3}Ge{sub 6} compounds (R=La, Ce, Pr, Nd). Band structure calculations indicate that both SrZn{sub 2}Sn{sub 2} and Ca{sub 2}Zn{sub 3}Sn{sub 6} are metallic. Analyses of the chemical bonding with the electron localization function (ELF) show lone pair like basins at Sn atoms and Zn-Sn bonding interactions between the layers for both title phases, and covalent Sn-Sn bonding within the {l_brace}Sn{sub 4}Zn{r_brace} layers of Ca{sub 2}Zn{sub 3}Sn{sub 6}. - Graphical abstract: Crystal structures of the new Ae-Zn-Sn polar intermetallic phases SrZn{sub 2}Sn{sub 2} and Ca{sub 2}Zn{sub 3}Sn{sub 6}. Highlights: Black-Right-Pointing-Pointer New polar intermetallic phases SrZn{sub 2}Sn{sub 2} and Ca{sub 2}Zn{sub 3}Sn{sub 6}. Black-Right-Pointing-Pointer Obtained by high temperature reactions of the elements. Black-Right-Pointing-Pointer Single crystal XRD structure determination and DFT electronic structure calculations. Black-Right-Pointing-Pointer Closely related crystal and electronic structures. Black-Right-Pointing-Pointer Metallic conductivity coexisting with lone pairs and covalent bonding features.

  5. The effect of ZnO surface conditions on the electronic structure of the ZnO/CuPc interface

    SciTech Connect (OSTI)

    Park, Sang Han; Kim, Hyo Jin; Cho, Mann-Ho [Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749 (Korea, Republic of); Yi, Yeonjin [Division of Industrial Metrology, KRISS, Daejeon 305-340 (Korea, Republic of); Cho, Sang Wan [Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215 (United States); Yang, Jaehyun; Kim, Hyoungsub [School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2011-02-21T23:59:59.000Z

    The interfacial electronic structures of zinc oxide (ZnO)/copper-phthalocyanine (CuPc) were investigated by in situ x-ray and ultraviolet photoelectron spectroscopy (UPS) to determine the effects of air contamination on the ZnO substrate. UPS spectra showed that the 0.2 eV of the interface dipole is generated at the interface of the air exposed ZnO/CuPc while the interface of the annealed ZnO/CuPc generated -0.2 eV. In both cases, no band bending was observed. On the other hand, band bending at 0.3 eV and an interface dipole of 0.2 eV were observed at the interface of the sputter cleaned ZnO/CuPc. The energy offset between the conduction band maximum of ZnO and the highest occupied molecular orbital of CuPc was determined to be 0.6-0.7 eV for the contaminated ZnO interface while the offset was 1.0 eV for the cleaned ZnO interface. Contaminating moisture has little effect on the offset while the charge transfer was blocked and the offset was decreased in the presence of hydrocarbons.

  6. ZnO/Cu(InGa)Se.sub.2 solar cells prepared by vapor phase Zn doping

    SciTech Connect (OSTI)

    Ramanathan, Kannan; Hasoon, Falah S.; Asher, Sarah E.; Dolan, James; Keane, James C.

    2007-02-20T23:59:59.000Z

    A process for making a thin film ZnO/Cu(InGa)Se.sub.2 solar cell without depositing a buffer layer and by Zn doping from a vapor phase, comprising: depositing Cu(InGa)Se.sub.2 layer on a metal back contact deposited on a glass substrate; heating the Cu(InGa)Se.sub.2 layer on the metal back contact on the glass substrate to a temperature range between about 100.degree. C. to about 250.degree. C.; subjecting the heated layer of Cu(InGa)Se.sub.2 to an evaporant species from a Zn compound; and sputter depositing ZnO on the Zn compound evaporant species treated layer of Cu(InGa)Se.sub.2.

  7. ZnO/Cu(InGa)Se2 solar cells prepared by vapor phase Zn doping

    DOE Patents [OSTI]

    Ramanathan, Kannan; Hasoon, Falah S.; Asher, Sarah E.; Dolan, James; Keane, James C.

    2007-02-20T23:59:59.000Z

    A process for making a thin film ZnO/Cu(InGa)Se2 solar cell without depositing a buffer layer and by Zn doping from a vapor phase, comprising: depositing Cu(InGa)Se2 layer on a metal back contact deposited on a glass substrate; heating the Cu(InGa)Se2 layer on the metal back contact on the glass substrate to a temperature range between about 100.degree. C. to about 250.degree. C.; subjecting the heated layer of Cu(InGa)Se2 to an evaporant species from a Zn compound; and sputter depositing ZnO on the Zn compound evaporant species treated layer of Cu(InGa)Se2.

  8. Air-gap gating of MgZnO/ZnO heterostructures

    SciTech Connect (OSTI)

    Tambo, T.; Falson, J., E-mail: falson@kwsk.t.u-tokyo.ac.jp; Kozuka, Y. [Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, Tokyo 113-8656 (Japan); Maryenko, D. [RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198 (Japan); Tsukazaki, A. [Institute for Materials Research (IMR), Tohoku University, Sendai 980-8577 (Japan); PRESTO, Japan Science and Technology Agency (JST), Tokyo 102-0075 (Japan); Kawasaki, M. [Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, Tokyo 113-8656 (Japan); RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198 (Japan)

    2014-08-28T23:59:59.000Z

    The adaptation of air-gap dielectric based field-effect transistor technology to controlling the MgZnO/ZnO heterointerface confined two-dimensional electron system (2DES) is reported. We find it possible to tune the charge density of the 2DES via a gate electrode spatially separated from the heterostructure surface by a distance of 5??m. Under static gating, the observation of the quantum Hall effect suggests that the charge carrier density remains homogeneous, with the 2DES in the 3?mm square sample the sole conductor. The availability of this technology enables the exploration of the charge carrier density degree of freedom in the pristine sample limit.

  9. REGULAR ARTICLE Stability of polar ZnO surfaces studied by pair potential

    E-Print Network [OSTI]

    Li, Weixue

    density method Keju Sun Hai-Yan Su Wei-Xue Li Received: 1 September 2013 / Accepted: 16 November 2013. The overestimation of the stability of the ZnO(0001)Zn terminal originates from more distribution of the transferred temperature sublimation processes indicated a higher sublimation rate of the ZnO(0001)Zn surface compared

  10. Methotrexate intercalated ZnAl-layered double hydroxide

    SciTech Connect (OSTI)

    Chakraborty, Manjusha; Dasgupta, Sudip; Soundrapandian, Chidambaram [Central Glass and Ceramic Research Institute, CSIR, 196 Raja S.C. Mullick Road, Kolkata 700032 (India); Chakraborty, Jui, E-mail: jui@cgcri.res.in [Central Glass and Ceramic Research Institute, CSIR, 196 Raja S.C. Mullick Road, Kolkata 700032 (India); Ghosh, Swapankumar, E-mail: swapankumar.ghosh2@mail.dcu.ie [National Institute for Interdisciplinary Science and Technology (NIIST), CSIR, Trivandrum 695019 (India); Mitra, Manoj K. [Department of Metallurgical and Materials Engineering, Jadavpur University, Kolkata 700032 (India); Basu, Debabrata [Central Glass and Ceramic Research Institute, CSIR, 196 Raja S.C. Mullick Road, Kolkata 700032 (India)

    2011-09-15T23:59:59.000Z

    The anticancerous drug methotrexate (MTX) has been intercalated into an ZnAl-layered double hydroxide (LDH) using an anion exchange technique to produce LDH-MTX hybrids having particle sizes in the range of 100-300 nm. X-ray diffraction studies revealed increases in the basal spacings of ZnAl-LDH-MTX hybrid on MTX intercalation. This was corroborated by the transmission electron micrographs, which showed an increase in average interlayer spacing from 8.9 A in pristine LDH to 21.3 A in LDH-MTX hybrid. Thermogravimetric analyses showed an increase in the decomposition temperature for the MTX molecule in the LDH-MTX hybrid indicating enhanced thermal stability of the drug molecule in the LDH nanovehicle. The cumulative release profile of MTX from ZnAl-LDH-MTX hybrids in phosphate buffer saline (PBS) at pH 7.4 was successfully sustained for 48 h following Rigter-Peppas model release kinetics via diffusion. - Graphical abstract: ZnAl-layered double hydroxide intercalated with methotrexate ({approx}34% loading) promises the possibility of use of ZnAl-LDH material as drug carrier and in controlled delivery. Highlights: > ZnAl-layered double hydroxide methotrexate nanohybrid has been synthesized. > XRD and TEM studies on nanohybrid revealed successful intercalation of methotrexate. > TG and CHN analyses showed {approx}34 wt% of methotrexate loading into the nanohybrid. > Possibility of use of ZnAl-LDH material as drug carrier and in delivery.

  11. Radioactive contamination of ZnWO4 crystal scintillators

    E-Print Network [OSTI]

    P. Belli; R. Bernabei; F. Cappella; R. Cerulli; F. A. Danevich; A. M. Dubovik; S. d'Angelo; E. N. Galashov; B. V. Grinyov; A. Incicchitti; V. V. Kobychev; M. Laubenstein; L. L. Nagornaya; F. Nozzoli; D. V. Poda; R. B. Podviyanuk; O. G. Polischuk; D. Prosperi; V. N. Shlegel; V. I. Tretyak; I. A. Tupitsyna; Ya. V. Vasiliev; Yu. Ya. Vostretsov

    2010-09-05T23:59:59.000Z

    The radioactive contamination of ZnWO4 crystal scintillators has been measured deep underground at the Gran Sasso National Laboratory (LNGS) of the INFN in Italy with a total exposure 3197 kg x h. Monte Carlo simulation, time-amplitude and pulse-shape analyses of the data have been applied to estimate the radioactive contamination of the ZnWO4 samples. One of the ZnWO4 crystals has also been tested by ultra-low background gamma spectrometry. The radioactive contaminations of the ZnWO4 samples do not exceed 0.002 -- 0.8 mBq/kg (depending on the radionuclide), the total alpha activity is in the range: 0.2 - 2 mBq/kg. Particular radioactivity, beta active 65Zn and alpha active 180W, has been detected. The effect of the re-crystallization on the radiopurity of the ZnWO4 crystal has been studied. The radioactive contamination of samples of the ceramic details of the set-ups used in the crystals growth has been checked by low background gamma spectrometry. A project scheme on further improvement of the radiopurity level of the ZnWO4 crystal scintillators is briefly addressed.

  12. String-Net Models with $Z_N$ Fusion Algebra

    E-Print Network [OSTI]

    Ling-Yan Hung; Yidun Wan

    2012-12-19T23:59:59.000Z

    We study the Levin-Wen string-net model with a $Z_N$ type fusion algebra. Solutions of the local constraints of this model correspond to $Z_N$ gauge theory and double Chern-simons theories with quantum groups. For the first time, we explicitly construct a spin-$(N-1)/2$ model with $Z_N$ gauge symmetry on a triangular lattice as an exact dual model of the string-net model with a $Z_N$ type fusion algebra on a honeycomb lattice. This exact duality exists only when the spins are coupled to a $Z_N$ gauge field living on the links of the triangular lattice. The ungauged $Z_N$ lattice spin models are a class of quantum systems that bear symmetry-protected topological phases that may be classified by the third cohomology group $H^3(Z_N,U(1))$ of $Z_N$. Our results apply also to any case where the fusion algebra is identified with a finite group algebra or a quantusm group algebra.

  13. Polarized Raman scattering of single ZnO nanorod

    SciTech Connect (OSTI)

    Yu, J. L., E-mail: jlyu@semi.ac.cn; Lai, Y. F., E-mail: laiyunfeng@gmail.com; Wang, Y. Z.; Cheng, S. Y. [Institute of Micro/Nano Devices and Solar Cells, School of Physics and Information Engineering, Fuzhou University, Fuzhou (China); Chen, Y. H. [Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China)

    2014-01-21T23:59:59.000Z

    Polarized Raman scattering measurement on single wurtzite c-plane (001) ZnO nanorod grown by hydrothermal method has been performed at room temperature. The polarization dependence of the intensity of the Raman scattering for the phonon modes A{sub 1}(TO), E{sub 1}(TO), and E{sub 2}{sup high} in the ZnO nanorod are obtained. The deviations of polarization-dependent Raman spectroscopy from the prediction of Raman selection rules are observed, which can be attributed to the structure defects in the ZnO nanorod as confirmed by the comparison of the transmission electron microscopy, photoluminescence spectra as well as the polarization dependent Raman signal of the annealed and unannealed ZnO nanorod. The Raman tensor elements of A{sub 1}(TO) and E{sub 1}(TO) phonon modes normalized to that of the E{sub 2}{sup high} phonon mode are |a/d|=0.320.01,?|b/d|=0.490.02, and |c/d|=0.230.01 for the unannealed ZnO nanorod, and |a/d|=0.330.01,?|b/d|=0.450.01, and |c/d|=0.200.01 for the annealed ZnO nanorod, which shows strong anisotropy compared to that of bulk ZnO epilayer.

  14. Mixed Zn and O substitution of Co and Mn in ZnO

    E-Print Network [OSTI]

    Pereira, Lino Miguel da Costa; Decoster, Stefan; Correia, Joo Guilherme; Amorim, Lgia Marina; da Silva, Manuel Ribeiro; Arajo, Joo Pedro; Vantomme, Andr

    2011-01-01T23:59:59.000Z

    The physical properties of an impurity atom in a semiconductor are primarily determined by the lattice site it occupies. In general, this occupancy can be correctly predicted based on chemical intuition, but not always. We report on one such exception in the dilute magnetic semiconductors Co- and Mn-doped ZnO, experimentally determining the lattice location of Co and Mn using ??-emission channeling from the decay of radioactive 61Co and 56Mn implanted at the ISOLDE facility at CERN. Surprisingly, in addition to the majority substituting for Zn, we find up to 18% (27%) of the Co (Mn) atoms in O sites, which is virtually unaffected by thermal annealing up to 900 C. We discuss how this anion site configuration, which had never been considered before for any transition metal in any metal oxide material, may in fact have a low formation energy. This suggests a change in paradigm regarding transition-metal incorporation in ZnO and possibly other oxides and wide-gap semiconductors.

  15. Pulse Electrodeposition of Cu-ZnO and Mn-Cu-ZnO Nanowires

    SciTech Connect (OSTI)

    Gupta, Mayank; Pinisetty, D.; Flake, John C.; Spivey, James J.

    2010-01-01T23:59:59.000Z

    CuZnO and MnCuZnO nanowires are attractive catalysts for alcohol synthesis from CO hydrogenation reactions. Nanowire alloys are pulse electrodeposited into track etched polycarbonate membranes using aqueous electrolytes including Mn(NO{sub 3} ){sub 2} , Cu(NO{sub 3} ){sub 2} , Zn(NO{sub 3} ){sub 2} , and NH{sub 4} NO{sub 3} . Pulse waveforms with a cathodic current density of 50.7mAcm{sup ?2} for 50 ms (on-time), with varying off-times (400, 500, and 600 ms), are used to fabricate nanowire arrays (400 nm diameter, 25?m long, and pore density of 1.510{sup 8} pores cm{sup ?2} ). Pulse waveforms allow significantly higher copper concentrations and better control of zinc and manganese concentrations within nanowires. X-ray diffraction results show preferential growth in the (111) direction and crystallite size increases with an increase in off-time. Waveforms with longer off-times (500 and 600 ms) resulted in nanowires with relatively higher copper concentrations due to improved copper transport in nanopores. The nanowire surface has no manganese; however, the core shows manganese, which increases with the decrease in off-time. The effect of deposition conditions and electrolyte composition on nanowire properties are explained and discussed.

  16. ZnO Nanocoral Structures for Photoelectrochemical Cells

    SciTech Connect (OSTI)

    Ahn, K. S.; Yan, Y.; Shet, S.; Jones, K.; Deutsch, T.; Turner, J.; Al-Jassim, M.

    2008-01-01T23:59:59.000Z

    We report on synthesis of a uniform and large area of a new form of ZnO nanocorals. These nanostructures can provide suitable electrical pathways for efficient carrier collection as well as large surface areas for the photoelectrochemical (PEC) cells. PEC devices made from these ZnO nanocoral structures demonstrate significantly enhanced photoresponse as compared to ZnO compact and nanorod films. Our results suggest that the nanocoral structures could be an excellent choice for nanomaterial-based applications such as dye-sensitized solar cells, electrochromic windows, and batteries.

  17. Minority anion substitution by Ni in ZnO

    E-Print Network [OSTI]

    Pereira, Lino Miguel da Costa; Correia, Joo Guilherme; Amorim, Lgia Marina; Silva, Daniel Jos; David-Bosne, Eric; Decoster, Stefan; da Silva, Manuel Ribeiro; Temst, Kristiaan; Vantomme, Andr

    2013-01-01T23:59:59.000Z

    We report on the lattice location of implanted Ni in ZnO using the $\\beta$? emission channeling technique. In addition to the majority substituting for the cation (Zn), a significant fraction of the Ni atoms occupy anion (O) sites. Since Ni is chemically more similar to Zn than it is to O, the observed O substitution is rather puzzling. We discuss these findings with respect to the general understanding of lattice location of dopants in compound semiconductors. In particular, we discuss potential implications on the magnetic behavior of transition metal doped dilute magnetic semiconductors.

  18. al pb zn: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    payload. The planar shield was designed to veto background countsproduced by local gamma-ray production in passive material and neutron interactions in the detector. The CdZnTe...

  19. Hot exciton transport in ZnSe quantum wells

    E-Print Network [OSTI]

    Zhao, Hui; Moehl, Sebastian; Wachter, Sven; Kalt, Heinz

    2002-02-01T23:59:59.000Z

    The in-plane transport of excitons in ZnSe quantum wells is investigated directly by microphotoluminescence in combination with a solid immersion lens. Due to the strong Froehlich coupling, the initial kinetic energy of the excitons is well...

  20. The Nature of Zn Precipitates Formed in the Presence of

    E-Print Network [OSTI]

    Sparks, Donald L.

    to the structure of various hydroxide- and carbonate-bearing phases indicates the formation of a Zn-Al layered metal sequestration mechanism in certain soil types is important to assessment of contaminant

  1. Microscopic picture of Co clustering in ZnO

    E-Print Network [OSTI]

    Iusan, Diana

    Density functional theory was applied to study the chemical and magnetic interactions between Co atoms doped in ZnO. It was found that the Co impurities tend to form nanoclusters and the interactions between these atoms ...

  2. DIRECT EVIDENCE OF MG-ZN-P ALLOY FORMATION IN MG/ZN3P2 SOLAR CELLS Gregory M. Kimball

    E-Print Network [OSTI]

    Kimball, Gregory

    Te, CIGS, a-Si) for thin film photovoltaics. The record solar energy conversion efficiency for Zn3P2 cellsDIRECT EVIDENCE OF MG-ZN-P ALLOY FORMATION IN MG/ZN3P2 SOLAR CELLS Gregory M. Kimball 1 , Nathan S indicate that high efficiency should be realizable by optimization of Mg treatment in Mg/Zn3P2 solar cells

  3. Selective Zn2+ sensing using a modified bipyridine complex

    SciTech Connect (OSTI)

    Akula, Mahesh; El-Khoury, Patrick Z.; Nag, Amit; Bhattacharya, Anupam

    2014-06-01T23:59:59.000Z

    A novel fluorescent Zn2+ sensor, 4-(pyridin-2-yl)-3H-pyrrolo[2, 3-c]quinoline (PPQ), has been designed, synthesized and characterized by various spectroscopic and analytical techniques. PPQ exhibits superior detection of Zn2+ in the presence of various cations tested, including Cd2+ and Hg2+, via wavelength shifted fluorescence intensity enhancement. The emission wavelength at 500 nm, ensures probable noninterference from cellular components while performing biological applications.

  4. Electron Transfer Between Colloidal ZnO Nanocrystals

    SciTech Connect (OSTI)

    Hayoun, Rebecca; Whitaker, Kelly M.; Gamelin, Daniel R.; Mayer, James M.

    2011-03-30T23:59:59.000Z

    Colloidal ZnO nanocrystals capped with dodecylamine and dissolved in toluene can be charged photochemically to give stable solutions in which electrons are present in the conduction bands of the nanocrystals. These conduction-band electrons are readily monitored by EPR spectroscopy, with g* values that correlate with the nanocrystal sizes. Mixing a solution of charged small nanocrystals (e{sub CB}{sup -}:ZnO-S) with a solution of uncharged large nanocrystals (ZnO-L) caused changes in the EPR spectrum indicative of quantitative electron transfer from small to large nanocrystals. EPR spectra of the reverse reaction, e{sub CB}{sup -}:ZnO-L + ZnO-S, showed that electrons do not transfer from large to small nanocrystals. Stopped-flow kinetics studies monitoring the change in the UV bandedge absorption showed that reactions of 50 {micro}M nanocrystals were complete within the 5 ms mixing time of the instrument. Similar results were obtained for the reaction of charged nanocrystals with methyl viologen (MV{sup 2+}). These and related results indicate that the electron-transfer reactions of these colloidal nanocrystals are quantitative and very rapid, despite the presence of {approx}1.5 nm long dodecylamine capping ligands. These soluble ZnO nanocrystals are thus well-defined redox reagents suitable for studies of electron transfer involving semiconductor nanostructures.

  5. Radioactive contamination of ZnWO4 crystal scintillators

    E-Print Network [OSTI]

    Belli, P; Cappella, F; Cerulli, R; Danevich, F A; Dubovik, A M; d'Angelo, S; Galashov, E N; Grinyov, B V; Incicchitti, A; Kobychev, V V; Laubenstein, M; Nagornaya, L L; Nozzoli, F; Poda, D V; Podviyanuk, R B; Polischuk, O G; Prosperi, D; Shlegel, V N; Tretyak, V I; Tupitsyna, I A; Vasiliev, Ya V; Vostretsov, Yu Ya

    2010-01-01T23:59:59.000Z

    The radioactive contamination of ZnWO4 crystal scintillators has been measured deep underground at the Gran Sasso National Laboratory (LNGS) of the INFN in Italy with a total exposure 3197 kg x h. Monte Carlo simulation, time-amplitude and pulse-shape analyses of the data have been applied to estimate the radioactive contamination of the ZnWO4 samples. One of the ZnWO4 crystals has also been tested by ultra-low background gamma spectrometry. The radioactive contaminations of the ZnWO4 samples do not exceed 0.002 ?? 0.8 mBq/kg (depending on the radionuclide), the total alpha activity is in the range: 0.2 - 2 mBq/kg. Particular radioactivity, beta active 65Zn and alpha active 180W, has been detected. The effect of the re-crystallization on the radiopurity of the ZnWO4 crystal has been studied. The radioactive contamination of samples of the ceramic details of the set-ups used in the crystals growth has been checked by low background gamma spectrometry. A project scheme on further improvement of the radiopur...

  6. Non-oxidative reactions of propane on Zn/Na-ZSM5 Joseph A. Biscardi and Enrique Iglesia*

    E-Print Network [OSTI]

    Iglesia, Enrique

    Non-oxidative reactions of propane on Zn/Na-ZSM5 Joseph A. Biscardi and Enrique Iglesia* Department rates during propane conversion at 773 K on Zn/Na-ZSM5 are about ten times higher than on Zn/H-ZSM5 catalysts with similar Zn content. The total rate of propane conversion is also higher on Zn/Na-ZSM5

  7. Formation of Zn-rich phyllosilicate, Zn-layered double hydroxide and hydrozincite in contaminated calcareous soils

    E-Print Network [OSTI]

    Jacquat, Olivier

    2009-01-01T23:59:59.000Z

    and chemical extractions. Am. Mineral. 88, 509-526.extraction for speciation of trace- metals in model soil containing natural mineralson these minerals). Prior to extraction, the Zn-phases were

  8. Syntheses, crystal structures and characterizations of BaZn(SeO{sub 3}){sub 2} and BaZn(TeO{sub 3})Cl{sub 2}

    SciTech Connect (OSTI)

    Jiang Hailong [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, and the Graduate School of the Chinese Academy of Sciences, Fuzhou 350002 (China); Feng Meiling [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, and the Graduate School of the Chinese Academy of Sciences, Fuzhou 350002 (China); Mao Jianggao [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, and the Graduate School of the Chinese Academy of Sciences, Fuzhou 350002 (China)]. E-mail: mjg@ms.fjirsm.ac.cn

    2006-06-15T23:59:59.000Z

    Two new barium zinc selenite and tellurite, namely, BaZn(SeO{sub 3}){sub 2} and BaZn(TeO{sub 3})Cl{sub 2}, have been synthesized by the solid state reaction. The structure of BaZn(SeO{sub 3}){sub 2} features double chains of [Zn(SeO{sub 3}){sub 2}]{sup 2-} anions composed of four- and eight-member rings which are alternatively along a-axis. The double chains of [Zn{sub 2}(TeO{sub 3}){sub 2}Cl{sub 3}]{sup 3-} anions in BaZn(TeO{sub 3})Cl{sub 2} are formed by Zn{sub 3}Te{sub 3} rings in which each tellurite group connects with three ZnO{sub 3}Cl tetrahedra. BaZn(SeO{sub 3}){sub 2} and BaZn(TeO{sub 3})Cl{sub 2} are wide bandgap semiconductors based on optical diffuse reflectance spectrum measurements. -- Graphical abstract: Two new barium zinc selenite and tellurite, namely, BaZn(SeO{sub 3}){sub 2} and BaZn(TeO{sub 3})Cl{sub 2}, have been synthesized by solid state reaction. The structure of BaZn(SeO{sub 3}){sub 2} features 1D double chains of [Zn(SeO{sub 3}){sub 2}]{sup 2-} anions composed of four- and eight-member rings which are alternatively along a-axis. The 1D double chains of [Zn{sub 2}(TeO{sub 3}){sub 2}Cl{sub 3}]{sup 3-} anions in BaZn(TeO{sub 3})Cl{sub 2} are formed by Zn{sub 3}Te{sub 3} rings in which each tellurite group connects with one ZnO{sub 3}Cl and two ZnO{sub 2}Cl{sub 2} tetrahedra. BaZn(SeO{sub 3}){sub 2} and BaZn(TeO{sub 3})Cl{sub 2} are wide bandgap semiconductors based on optical diffuse reflectance spectrum measurements.

  9. Synthesis of reduced graphene oxide/ZnO nanorods composites on graphene coated PET flexible substrates

    SciTech Connect (OSTI)

    Huang, Lei, E-mail: leihuang@shnu.edu.cn; Guo, Guilue; Liu, Yang; Chang, Quanhong; Shi, Wangzhou

    2013-10-15T23:59:59.000Z

    Graphical abstract: - Highlights: ZnO nanorods synthesized on CVD-graphene and rGO surfaces, respectively. ZnO/CVD-graphene and ZnO/rGO form a distinctive porous 3D structure. rGO/ZnO nanostructures possibility in energy storage devices. - Abstract: In this work, reduced graphene oxide (rGO)/ZnO nanorods composites were synthesized on graphene coated PET flexible substrates. Both chemical vapor deposition (CVD) graphene and reduced graphene oxide (rGO) films were prepared following by hydrothermal growth of vertical aligned ZnO nanorods. Reduced graphene sheets were then spun coated on the ZnO materials to form a three dimensional (3D) porous nanostructure. The morphologies of the ZnO/CVD graphene and ZnO/rGO were investigated by SEM, which shows that the ZnO nanorods grown on rGO are larger in diameters and have lower density compared with those grown on CVD graphene substrate. As a result of fact, the rough surface of nano-scale ZnO on rGO film allows rGO droplets to seep into the large voids of ZnO nanorods, then to form the rGO/ZnO hierarchical structure. By comparison of the different results, we conclude that rGO/ZnO 3D nanostructure is more desirable for the application of energy storage devices.

  10. Anisotropic strain effects on the photoluminescence emission from heteroepitaxial and homoepitaxial nonpolar (Zn,Mg)O/ZnO quantum wells

    SciTech Connect (OSTI)

    Chauveau, J.-M.; Vinter, B. [Centre de Recherche sur l'Hetero-Epitaxie et ses Applications, Centre National de la Recherche Scientifique (CRHEA-CNRS), Rue B. Gregory, F-06560 Valbonne Sophia Antipolis (France); University of Nice Sophia Antipolis, Parc Valrose, F-06102 Nice Cedex 2 (France); Teisseire, M.; Morhain, C.; Deparis, C. [Centre de Recherche sur l'Hetero-Epitaxie et ses Applications, Centre National de la Recherche Scientifique (CRHEA-CNRS), Rue B. Gregory, F-06560 Valbonne Sophia Antipolis (France); Kim-Chauveau, H.

    2011-05-15T23:59:59.000Z

    We report on the properties of nonpolar a-plane (Zn,Mg)O/ZnO quantum wells (QW) grown by molecular beam epitaxy on r plane sapphire and a plane ZnO substrates. For the QWs grown on sapphire, the anisotropy of the lattice parameters of the (Zn,Mg)O barrier gives rise to an unusual in-plane strain state in the ZnO QWs, which induces a strong blue-shift of the excitonic transitions, in addition to the confinement effects. We observe this blue-shift in photoluminescence excitation experiments. The photoluminescence excitation energies of the QWs are satisfactorily simulated when taking into account the variation of the exciton binding energy with the QW width and the residual anisotropic strain. Then we compare the photoluminescence properties of homoepitaxial QWs grown on ZnO bulk substrate and heteroepitaxial QWs grown on sapphire. We show that the reduction of structural defects and the improvement of surface morphology are correlated with a strong enhancement of the photoluminescence properties: reduction of full width at half maximum, strong increase of the luminescence intensities. The comparison convincingly demonstrates the interest of homoepitaxial nonpolar QWs for bright UV emission applications.

  11. ZnO/ZnS(O,OH)/Cu(In,Ga)Se2/Mo SOLAR CELL WITH 18.6% EFFICIENCY M.A. Contreras, 2

    E-Print Network [OSTI]

    Sites, James R.

    of the deposition rate control. Figure 1. Total-area current-voltage data for MgF2/ZnO/ZnS(O,OH)/CIGS/Mo solar cellZnO/ZnS(O,OH)/Cu(In,Ga)Se2/Mo SOLAR CELL WITH 18.6% EFFICIENCY 1 M.A. Contreras, 2 T. Nakada, 2 M of 18.6% for Cu(In,Ga)Se2 solar cells that incorporate a ZnS(O,OH) buffer layer as an alternative to Cd

  12. Photoluminescence study of the substitution of Cd by Zn during the growth by atomic layer epitaxy of alternate CdSe and ZnSe monolayers

    SciTech Connect (OSTI)

    Hernndez-Caldern, I. [Physics Department,Cinvestav, Ave. IPN2508, 07360, Mxico City, DF. (Mexico); Salcedo-Reyes, J. C. [Thin Films Group, Physics Department, Pontificia Universidad Javeriana, Cr. 7 No. 43-82, Ed. 53, Lab. 404, Bogot, D.C. (Colombia)

    2014-05-15T23:59:59.000Z

    We present a study of the substitution of Cd atoms by Zn atoms during the growth of alternate ZnSe and CdSe compound monolayers (ML) by atomic layer epitaxy (ALE) as a function of substrate temperature. Samples contained two quantum wells (QWs), each one made of alternate CdSe and ZnSe monolayers with total thickness of 12 ML but different growth parameters. The QWs were studied by low temperature photoluminescence (PL) spectroscopy. We show that the Cd content of underlying CdSe layers is affected by the exposure of the quantum well film to the Zn flux during the growth of ZnSe monolayers. The amount of Cd of the quantum well film decreases with higher exposures to the Zn flux. A brief discussion about the difficulties to grow the Zn{sub 0.5}Cd{sub 0.5}Se ordered alloy (CuAu-I type) by ALE is presented.

  13. One-step electrochemical synthesis of a grapheneZnO hybrid for improved photocatalytic activity

    SciTech Connect (OSTI)

    Wei, Ang; Xiong, Li; Sun, Li; Liu, Yanjun; Li, Weiwei; Lai, Wenyong; Liu, Xiangmei; Wang, Lianhui [Key Laboratory for Organic Electronics and Information Displays (KLOEID), Nanjing University of Posts and Telecommunications (NUPT), Nanjing 210046 (China); Huang, Wei, E-mail: iamwhuang@njut.edu.cn [Institute of Advanced Materials, Nanjing University of Technology, Nanjing 210009 (China); Dong, Xiaochen, E-mail: iamxcdong@njut.edu.cn [Key Laboratory for Organic Electronics and Information Displays (KLOEID), Nanjing University of Posts and Telecommunications (NUPT), Nanjing 210046 (China); Institute of Advanced Materials, Nanjing University of Technology, Nanjing 210009 (China)

    2013-08-01T23:59:59.000Z

    Graphical abstract: - Highlights: GrapheneZnO hybrid was synthesized by one-step electrochemical deposition. GrapheneZnO hybrid presents a special structure and wide UVvis absorption spectra. GrapheneZnO hybrid exhibits an exceptionally higher photocatalytic activity for the degradation of dye methylene blue. - Abstract: A grapheneZnO (G-ZnO) hybrid was synthesized by one-step electrochemical deposition. During the formation of ZnO nanostructure by cathodic electrochemical deposition, the graphene oxide was electrochemically reduced to graphene simultaneously. Scanning electron microscope images, X-ray photoelectron spectroscopy, X-ray diffraction, Raman spectra, and UVvis absorption spectra indicate the resulting G-ZnO hybrid presents a special structure and wide UVvis absorption spectra. More importantly, it exhibits an exceptionally higher photocatalytic activity for the degradation of dye methylene blue than that of pure ZnO nanostructure under both ultraviolet and sunlight irradiation.

  14. Fluorescent Dye Encapsulated ZnO Particles with Cell-specific...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the visible fluorescence emission of the dye or UV fluorescence emission of ZnO, and anti-cancerantibacterial treatments using the selective toxicity of the nanoscale ZnO outer...

  15. ZnS Thin Films Deposited by a Spin Successive Ionic Layer Adsorption...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ZnS Thin Films Deposited by a Spin Successive Ionic Layer Adsorption and Reaction Process. ZnS Thin Films Deposited by a Spin Successive Ionic Layer Adsorption and Reaction...

  16. Pressure Behaviour of the UV and Green Emission Bands in ZnO...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Pressure Behaviour of the UV and Green Emission Bands in ZnO Micro-rods. Pressure Behaviour of the UV and Green Emission Bands in ZnO Micro-rods. Abstract: The pressure behavior of...

  17. Defects in paramagnetic Co-doped ZnO films studied by transmission...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Abstract: We have studied planar defects in epitaxial Co:ZnO dilute magnetic semiconductor thin films deposited on c-plane sapphire (Al2O3) and the Co:ZnOAl2O3...

  18. Mid-Gap Electronic States in Zn1 xMnxO. | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    measurements were performed on epitaxial Zn1 xMnxO films to investigate the origin of the new mid-gap band that appears upon introduction of Mn2+ into the ZnO lattice. Absorption...

  19. Luminescence Temperature and Pressure Studies of Zn2SiO4 Phosphors...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Temperature and Pressure Studies of Zn2SiO4 Phosphors Doped with Mn2+ and Eu3+ Ions. Luminescence Temperature and Pressure Studies of Zn2SiO4 Phosphors Doped with Mn2+ and Eu3+...

  20. On the room-temperature ferromagnetism of Zn1-xCrxO thin films...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    On the room-temperature ferromagnetism of Zn1-xCrxO thin films deposited by reactive co-sputtering. On the room-temperature ferromagnetism of Zn1-xCrxO thin films deposited by...

  1. An improved understanding of fluorescent Zn(II) sensors and their uses in biological settings

    E-Print Network [OSTI]

    Wong, Brian Alexander

    2009-01-01T23:59:59.000Z

    Chapter 1. An Introduction to Fluorescent Zn(II) Sensors and Their Applications in Biological Systems This chapter opens with an overview of the numerous roles of zinc in biology, with an emphasis on labile Zn(II), that ...

  2. Syngas Conversion to Gasoline-Range Hydrocarbons over Pd/ZnO...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Syngas Conversion to Gasoline-Range Hydrocarbons over PdZnOAl2O3 and ZSM-5 Composite Catalyst System. Syngas Conversion to Gasoline-Range Hydrocarbons over PdZnOAl2O3 and ZSM-5...

  3. Electronic properties of H and D doped ZnO epitaxial films. ...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of H and D doped ZnO epitaxial films. Abstract: ZnO epitaxial films grown by pulsed laser deposition in an ambient of H2 or D2 exhibit qualitatively different electronic...

  4. PdZnAl Catalysts for the Reactions of Water-Gas-Shift, Methanol...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    PdZnAl Catalysts for the Reactions of Water-Gas-Shift, Methanol Steam Reforming, and Reverse-Water-Gas-Shift. PdZnAl Catalysts for the Reactions of Water-Gas-Shift, Methanol Steam...

  5. CO/FTIR Spectroscopic Characterization of Pd/ZnO/Al2O3 Catalysts...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    COFTIR Spectroscopic Characterization of PdZnOAl2O3 Catalysts for Methanol Steam Reforming. COFTIR Spectroscopic Characterization of PdZnOAl2O3 Catalysts for Methanol Steam...

  6. Structural Studies of Al:ZnO Powders and Thin Films | Stanford...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Ingham, Associate Investigator, MacDiarmid Institute for Advanced Materials & Nanotechnology Al-doped ZnO (Al:ZnO) is a promising transparent conducting oxide. We have used...

  7. High mobility ZnO nanowires for terahertz detection applications

    SciTech Connect (OSTI)

    Liu, Huiqiang [State Key Laboratory of Optoelectronic Materials and Technology, Sun Yat-Sen University, Guangdong, Guangzhou 510275 (China); State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Sichuan, Mianyang 621010 (China); Peng, Rufang, E-mail: pengrufang@swust.edu.cn, E-mail: chusheng@mail.sysu.edu.cn; Chu, Shijin [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Sichuan, Mianyang 621010 (China); Chu, Sheng, E-mail: pengrufang@swust.edu.cn, E-mail: chusheng@mail.sysu.edu.cn [State Key Laboratory of Optoelectronic Materials and Technology, Sun Yat-Sen University, Guangdong, Guangzhou 510275 (China)

    2014-07-28T23:59:59.000Z

    An oxide nanowire material was utilized for terahertz detection purpose. High quality ZnO nanowires were synthesized and field-effect transistors were fabricated. Electrical transport measurements demonstrated the nanowire with good transfer characteristics and fairly high electron mobility. It is shown that ZnO nanowires can be used as building blocks for the realization of terahertz detectors based on a one-dimensional plasmon detection configuration. Clear terahertz wave (?0.3?THz) induced photovoltages were obtained at room temperature with varying incidence intensities. Further analysis showed that the terahertz photoresponse is closely related to the high electron mobility of the ZnO nanowire sample, which suggests that oxide nanoelectronics may find useful terahertz applications.

  8. Process for fabricating ZnO-based varistors

    DOE Patents [OSTI]

    Lauf, Robert J. (Oak Ridge, TN)

    1985-01-01T23:59:59.000Z

    The invention is a process for producing ZnO-based varistors incorporating a metal oxide dopant. In one form, the invention comprises providing a varistor powder mix of colloidal particles of ZnO and metal-oxide dopants including Bi.sub.2 O.sub.3. The mix is hot-pressed to form a compact at temperatures below 850.degree. C. and under conditions effecting reduction of the ZnO to sub-stoichiometric oxide. This promotes densification while restricting liquid formation and grain growth. The compact then is heated under conditions restoring the zinc oxide to stoichiometric composition, thus improving the varistor properties of the compact. The process produces fine-grain varistors characterized by a high actual breakdown voltage and a high average breakdown voltage per individual grain boundary.

  9. Nitrogen is a deep acceptor in ZnO

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    McCluskey, M.D. [Washington State Univ., Pullman, WA (United States); Tarun, M.C. [Washington State Univ., Pullman, WA (United States); Iqbal, M. Zafar [COMSATS Institute of Information Technology, Islamabad (Pakistan)

    2011-04-14T23:59:59.000Z

    Zinc oxide is a promising material for blue and UV solid-state lighting devices, among other applications. Nitrogen has been regarded as a potential p-type dopant for ZnO. However, recent calculations [Lyons, Janotti, and Van de Walle, Appl. Phys. Lett. 95, 252105 (2009)] indicate that nitrogen is a deep acceptor. This paper presents experimental evidence that nitrogen is, in fact, a deep acceptor and therefore cannot produce p-type ZnO. A broad photoluminescence (PL) emission band near 1.7 eV, with an excitation onset of ~2.2 eV, was observed, in agreement with the deep-acceptor model of the nitrogen defect. The deep-acceptor behavior can be explained by the low energy of the ZnO valence band relative to the vacuum level.

  10. Structural recovery of ion implanted ZnO nanowires G. Perillat-Merceroz,1, 2, a)

    E-Print Network [OSTI]

    Boyer, Edmond

    applications, ZnO nanowires are studied for making light- emitting diodes (LEDs) because of the advantages

  11. Heat treatment effects on microstructure and magnetic properties of MnZn ferrite powders

    E-Print Network [OSTI]

    Volinsky, Alex A.

    Heat treatment effects on microstructure and magnetic properties of Mn­Zn ferrite powders Ping Hu Available online 6 September 2009 Keywords: Mn­Zn ferrite Heat treatment Microstructure Magnetic property a b s t r a c t Mn­Zn ferrite powders (Mn0.5Zn0.5Fe2O4) were prepared by the nitrate­citrate auto

  12. Magneto-optical Kerr rotation enhancement in CoZnO inhomogeneous magnetic semiconductor

    E-Print Network [OSTI]

    Liu, J. Ping

    impurity doping, the doped ZnO can be used as transparent electrodes in solar cells and flat panel display

  13. Effect of ZnO seed layer on the morphology and optical properties of ZnO nanorods grown on GaN buffer layers

    SciTech Connect (OSTI)

    Nandi, R., E-mail: rajunandi@iitb.ac.in; Mohan, S., E-mail: rajunandi@iitb.ac.in; Major, S. S. [Department of Physics, Indian Institute of Technology Bombay, Mumbai - 400076 (India); Srinivasa, R. S. [Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai - 400076 (India)

    2014-04-24T23:59:59.000Z

    ZnO nanorods were grown by chemical bath deposition on sputtered, polycrystalline GaN buffer layers with and without ZnO seed layer. Scanning electron microscopy and X-ray diffraction show that the ZnO nanorods on GaN buffer layers are not vertically well aligned. Photoluminescence spectrum of ZnO nanorods grown on GaN buffer layer, however exhibits a much stronger near-band-edge emission and negligible defect emission, compared to the nanorods grown on ZnO buffer layer. These features are attributed to gallium incorporation at the ZnO-GaN interface. The introduction of a thin (25 nm) ZnO seed layer on GaN buffer layer significantly improves the morphology and vertical alignment of ZnO-NRs without sacrificing the high optical quality of ZnO nanorods on GaN buffer layer. The presence of a thick (200 nm) ZnO seed layer completely masks the effect of the underlying GaN buffer layer on the morphology and optical properties of nanorods.

  14. Structure of graphene oxide dispersed with ZnO nanoparticles

    SciTech Connect (OSTI)

    Yadav, Rishikesh, E-mail: rishikesh.yadav62@gmail.com; Pandey, Devendra K., E-mail: devendrakphy@gmail.com [School of Nanotechnology, Rajiv Gandhi Proudyogiki Vishwavidalaya, Bhopal, M.P. (India); Khare, P. S., E-mail: purnimaswarup@hotmail.com [Department of Physics, Rajiv Gandhi Proudyogiki Vishwavidalaya, Bhopal M.P. (India)

    2014-10-15T23:59:59.000Z

    Graphene has been proposed as a promising two-dimensional nanomaterial with outstanding electronic, optical, thermal and mechanical properties for many applications. In present work a process of dispersion of graphene oxide with ZnO nanoparticles in ethanol solution with different pH values, have been studied. Samples have been characterized by XRD, SEM, PL, UV-visible spectroscopy and particles size measurement. The results analysis indicates overall improved emission spectrum. It has been observed that the average diameter of RGO (Reduced Graphene Oxide) decreases in presence of ZnO nanoparticles from 3.8?m to 0.41?m.

  15. Effect of the (OH) Surface Capping on ZnO Quantum Dots

    E-Print Network [OSTI]

    Nabben, Reinhard

    in air at different temperatures from 150500 C for 30 min. In comparison, highly purified bulk Zn is related to oxygen deficiency [1]; the other is a much narrower ultraviolet (UV) emission band at around, compared with good quality ZnO single crystals or ZnO powders, the UV bandgap luminescence in quantum dots

  16. Characterization of surface and nonlinear elasticity in wurtzite ZnO nanowires J. Yvonnet,1, a)

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Characterization of surface and nonlinear elasticity in wurtzite ZnO nanowires J. Yvonnet,1, a) A­25 . Several first-principles studies have been conducted on wurtzite ZnO surfaces26­32 . Marana et al.33 have effects and their relation to size-dependent effective properties of ZnO wurtzite nanowires, by means

  17. Zn exchangeability in soils1 Zinc speciation and isotopic exchangeability in soils polluted with3

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    -step selective sequential extraction (SSE) in incubated soils30 and by identifying Zn forms in soils using were extracted in the 4th step of37 the SSE, while the rest of the 3rd pool was extracted in the final. Other species included strongly sorbed Zn species41 and Zn species in crystalline minerals. The EXAFS

  18. Corrosion of, and cellular responses to MgZnCa bulk metallic glasses Xuenan Gu a

    E-Print Network [OSTI]

    Zheng, Yufeng

    Corrosion of, and cellular responses to Mg­Zn­Ca bulk metallic glasses Xuenan Gu a , Yufeng Zheng a: Magnesium alloy Bulk metallic glass Mechanical property Corrosion Cytotoxicity a b s t r a c t Mg­Zn­Ca bulk, mechanical testing, corrosion and cytotoxicity tests. It was found that the Mg66Zn30Ca4 sample presents

  19. Remote plasma enhanced atomic layer deposition of ZnO for thin film electronic applications

    E-Print Network [OSTI]

    Zheludev, Nikolay

    Remote plasma enhanced atomic layer deposition of ZnO for thin film electronic applications S: Available online 28 May 2012 Keywords: Remote plasma Atomic layer deposition (ALD) ZnO Thin film transistor of various reactant plasma parameters of remote plasma enhanced ALD (PEALD) on the ZnO thin film properties

  20. Defect Chemistry Study of Nitrogen Doped ZnO Thin Films

    SciTech Connect (OSTI)

    Miami University: Dr. Lei L. Kerr (PI, PD) Wright State University: Dr. David C. Look (PI) and Dr. Zhaoqiang Fang (Co-PI)

    2009-11-29T23:59:59.000Z

    Our team has investigated the defect chemistry of ZnO:N and developed a thermal evaporation (vapor-phase) method to synthesis p-type ZnO:N. Enhanced p-type conductivity of nitrogen doped ZnO via nano/micro structured rods and Zn-rich Co-doping process were studied. Also, an extended X-Ray absorption fine structure study of p-type nitrogen doped ZnO was conducted. Also reported are Hall-effect, photoluminescence, and DLTS studies.

  1. ZnO Nanotube Based Dye-Sensitized Solar Cells

    E-Print Network [OSTI]

    ZnO Nanotube Based Dye-Sensitized Solar Cells Alex B. F. Martinson,, Jeffrey W. Elam, Joseph T templated by anodic aluminum oxide for use in dye-sensitized solar cells (DSSCs). Atomic layer deposition of the best dye- sensitized solar cells (DSSCs) is the product of a dye with moderate extinction

  2. First principle study of elastic and thermodynamic properties of ZrZn{sub 2} and HfZn{sub 2} under high pressure

    SciTech Connect (OSTI)

    Sun, Na; Zhang, Xinyu, E-mail: jiaqianqin@gmail.com; Ning, Jinliang; Zhang, Suhong; Liang, Shunxing; Ma, Mingzhen; Liu, Riping [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Qin, Jiaqian, E-mail: jiaqianqin@gmail.com [Metallurgy and Materials Science Research Institute, Chulalongkorn University, Bangkok 10330 (Thailand)

    2014-02-28T23:59:59.000Z

    A comprehensive investigation of the structural, elastic, and thermodynamic properties for Laves-phases ZrZn{sub 2} and HfZn{sub 2} are conducted using density functional total energy calculations combined with the quasi-harmonic Debye model. The optimized lattice parameters of ZrZn{sub 2} and HfZn{sub 2} compare well with available experimental values. We estimated the mechanical behaviors of both compounds under compression, including mechanical stability, Young's modulus, Poisson's ratio, ductility, and anisotropy. Additionally, the thermodynamic properties as a function of pressure and temperature are analyzed and found to be in good agreement with the corresponding experimental data.

  3. Development of a new electrodeposition process for plating of Zn-Ni-X (X=Cd, P) alloys. 1. Corrosion characteristics of Zn-Ni-Cd ternary alloys

    SciTech Connect (OSTI)

    Durairajan, A.; Haran, B.S.; White, R.E.; Popov, B.N.

    2000-05-01T23:59:59.000Z

    A new Zn-Ni-Cd plating process was developed which offers a unique way of controlling and optimizing the Ni and Cd contents in the final deposit. Zinc-nickel-cadmium alloy was deposited from a 0.5 M NiSO{sub 4} + 0.2 M ZnSO{sub 4} bath in the presence of 0.015 M CdSO{sub 4} and 1 g/L nonyl phenyl polyethylene oxide. Using this process a Zn-Ni-Cd ternary alloy, with a higher nickel content as compared to that obtained from conventional Zn-Ni baths, was synthesized. The Zn-Ni-Cd alloy coatings deposited from an electrolyte containing 0.015 M (0.3%) CdSO{sub 4} has a Zn to Ni ratio of 2.5:1. The increase in nickel content accounts for the observed decrease in the corrosion potential to a value lower than that of Cd but higher than the corrosion potential of iron. The coatings have superior corrosion resistance and barrier properties than the typical Zn-Ni and cadmium coatings. Polarization studies and electrochemical impedance spectroscopy analysis on Zn-Ni-Cd coatings show a barrier resistance that is ten times higher than that of a conventional Zn-Ni coating.

  4. Nano Res. 2012, 5(6): 412420412 Reshaping the Tips of ZnO Nanowires by Pulsed Laser

    E-Print Network [OSTI]

    Wang, Zhong L.

    Nano Res. 2012, 5(6): 412­420412 Reshaping the Tips of ZnO Nanowires by Pulsed Laser Irradiation to the body of the ZnO nanowire, and that the center of the sphere is hollow. The growth mechanism of the hollow ZnO nanospheres is proposed to involve laser-induced ZnO evaporation immediately followed by re

  5. Ordered zinc-vacancy induced Zn0.75Ox nanophase structure Yong Ding, Rusen Yang, Zhong Lin Wang *

    E-Print Network [OSTI]

    Wang, Zhong L.

    induced by Zn-vacancy has been discovered to grow on wurtzite ZnO nanobelts. The superstructure grows epitaxial from the f0110g surface of the wurtzite ZnO nanobelts and can be fitted as an orthorhombic surfaces of the wurtzite structured ZnO nanobelts and can be fitted as an orthorhombic structure

  6. Resorption Rate Tunable Bioceramic: Si, Zn-Modified Tricalcium Phosphate

    SciTech Connect (OSTI)

    Xiang Wei

    2006-08-09T23:59:59.000Z

    This dissertation is organized in an alternate format. Several manuscripts which have already been published or are to be submitted for publication have been included as separate chapters. Chapter 1 is a general introduction which describes the dissertation organization and introduces the human bone and ceramic materials as bone substitute. Chapter 2 is the background and literature review on dissolution behavior of calcium phosphate, and discussion of motivation for this research. Chapter 3 is a manuscript entitled ''Si,Zn-modified tricalcium phosphate: a phase composition and crystal structure study'', which was published in ''Key Engineering Materials'' [1]. Chapter 4 gives more crystal structure details by neutron powder diffraction, which identifies the position for Si and Zn substitution and explains the stabilization mechanism of the structure. A manuscript entitled ''Crystal structure analysis of Si, Zn-modified Tricalcium phosphate by Neutron Powder Diffraction'' will be submitted to Biomaterials [2]. Chapter 5 is a manuscript, entitled ''Dissolution behavior and cytotoxicity test of Si, Zn-modified tricalcium phosphate'', which is to be submitted to Biomaterials [3]. This paper discusses the additives effect on the dissolution behavior of TCP, and cytotoxicity test result is also included. Chapter 6 is the study of hydrolysis process of {alpha}-tricalcium phosphate in the simulated body fluid, and the phase development during drying process is discussed. A manuscript entitled ''Hydrolysis of {alpha}-tricalcium phosphate in simulated body fluid and phase transformation during drying process'' is to be submitted to Biomaterials [4]. Ozan Ugurlu is included as co-authors in these two papers due to his TEM contributions. Appendix A is the general introduction of the materials synthesis, crystal structure and preliminary dissolution result. A manuscript entitled ''Resorption rate tunable bioceramic: Si and Zn-modified tricalcium phosphate'' was published in Ceramic Engineering and Science Proceedings (the 29th International Conference on Advanced Ceramics and Composites - Advances in Bioceramics and Biocomposites) [5].

  7. Structural and optical properties of MgO doped ZnO

    SciTech Connect (OSTI)

    Verma, Kavita; Shukla, S.; Varshney, Dinesh, E-mail: vdinesh33@rediffmail.com [School of Physics, Vigyan Bhavan, Devi Ahilya University, Khandwa Road Campus, Indore-452001 (India); Varshney, M. [Department of Physics, M. B. Khalsa College, Raj Mohallah, Indore-452002 (India); Asthana, A. [Department of Chemistry, Govt. B. V. T. PG Autonomous College, Durg- 491001 (India)

    2014-04-24T23:59:59.000Z

    Samples of ZnO, Zn{sub 0.5}Mg{sub 0.5}O and MgO were prepared by co-precipitation method. X-ray diffraction (XRD) pattern infers that the sample of ZnO is in single-phase wurtzite structure (hexagonal phase, space group P6{sub 3}mc), MgO crystallizes in cubic Fd3m space group and Zn{sub 0.5}Mg{sub 0.5}O represents mixed nature of ZnO and MgO lattices. Similar features were observed from Raman spectroscopy. The energy band gaps estimated from UV-Vis spectroscopy are found to be 4.21 and 3.42 eV for ZnO and Zn{sub 0.5}Mg{sub 0.5}O samples respectively.

  8. Theoretical study of syngas hydrogenation to methanol on the polar Zn-terminated ZnO(0001) surface

    SciTech Connect (OSTI)

    Zhao, Ya-Fan; Rousseau, Roger J.; Li, Jun; Mei, Donghai

    2012-08-02T23:59:59.000Z

    Methanol synthesis from syngas (CO/CO2/H2) hydrogenation on the perfect Znterminated polar ZnO(0001) surface have been investigated using periodic density functional theory calculations. Our results show that direct CO2 hydrogenation to methanol on the perfect ZnO(0001) surface is unlikely because in the presence of surface atomic H and O the highly stable formate (HCOO) and carbonate (CO3) readily produced from CO2 with low barriers 0.11 and 0.09 eV will eventually accumulate and block the active sites of the ZnO(0001) surface. In contrast, methanol synthesis from CO hydrogenation is thermodynamically and kinetically feasible on the perfect ZnO(0001) surface. CO can be consecutively hydrogenated into formyl (HCO), formaldehyde (H2CO), methoxy (H3CO) intermediates, leading to the final formation of methanol (H3COH). The reaction route via hydroxymethyl (H2COH) intermediate, a previously proposed species on the defected Oterminated ZnO( ) surface, is kinetically inhibited on the perfect ZnO(0001) surface. The rate-determining step in the consecutive CO hydrogenation route is the hydrogenation of H3CO to H3COH. We also note that this last hydrogenation step is pronouncedly facilitated in the presence of water by lowering the activation barrier from 1.02 to 0.55 eV. This work was supported by the U.S. Department of Energy Office of Basic Energy Sciences, Division of Chemical Sciences, Biosciences and Geosciences, and performed at EMSL, a national scientific user facility sponsored by the Department of Energys Office of Biological and Environmental Research located at Pacific Northwest National Laboratory (PNNL). Computational resources were provided at EMSL and the National Energy Research Scientific Computing Center at Lawrence Berkeley National Laboratory. J. Li and Y.-F. Zhao were also financially supported by the National Natural Science Foundation of China (Nos. 20933003 and 91026003) and the National Basic Research Program of China (No. 2011CB932400). Y.-F. Zhao acknowledges the fellowship from PNNL.

  9. Transparent Conducting ZnO Thin Films Doped with Al and Mo

    SciTech Connect (OSTI)

    Duenow, J.; Gessert, T.; Wood, D.; Young, D.; Coutts, T.

    2007-01-01T23:59:59.000Z

    Transparent conducting oxide (TCO) thin films are a vital part of photovoltaic cells, flat-panel displays, and electrochromic windows. ZnO-based TCOs, due to the relative abundance of Zn, may reduce production costs compared to those of the prevalent TCO In2O3:Sn (ITO). Undoped ZnO, ZnO:Al (0.5, 1, and 2 wt.% Al2O3), and ZnO:Mo (2 wt.%) films were deposited by RF magnetron sputtering. Controlled incorporation of H2 in the Ar sputtering ambient increased mobility of undoped ZnO by a factor of ~20 to 48 cm2V-1s-1. H2 also appears to catalyze ionization of dopants. This enabled lightly doped ZnO:Al to provide comparable conductivity to the standard 2 wt.%-doped ZnO:Al while demonstrating reduced infrared absorption. Mo was found to be an n-type dopant of ZnO, though material properties did not match those of ZnO:Al. Scattering mechanisms were investigated using temperature-dependent Hall measurements and the method of four coefficients. This abstract is subject to government rights.

  10. Growth of Single- and Bilayer ZnO on Au(111) and Interaction with Copper

    SciTech Connect (OSTI)

    Deng, Xingyi; Yao, Kun; Sun, Keju; Li, Wei-Xue; Lee, Junseok; Matranga, Christopher

    2013-05-30T23:59:59.000Z

    The stoichiometric single- and bi-layer ZnO(0001) have been prepared by reactive deposition of Zn on Au(111) and studied in detail with X-ray photoelectron spectroscopy, scanning tunneling microscopy, and density functional theory calculations. Both single- and bi-layer ZnO(0001) adopt a planar, graphite-like structure similar to freestanding ZnO(0001) due to the weak van der Waals interactions dominating their adhesion with the Au(111) substrate. At higher temperature, the single-layer ZnO(0001) converts gradually to bi-layer ZnO(0001) due to the twice stronger interaction between two ZnO layers than the interfacial adhesion of ZnO with Au substrate. It is found that Cu atoms on the surface of bi-layer ZnO(0001) are mobile with a diffusion barrier of 0.31 eV, and likely to agglomerate and form nanosized particles at low coverages; while Cu atoms tend to penetrate a single layer of ZnO(0001) with a barrier of 0.10 eV, resulting in a Cu free surface.

  11. ZnS and ZnSe immersion gratings for astronomical high-resolution spectroscopy - evaluation of internal attenuation of bulk materials in the short NIR region

    SciTech Connect (OSTI)

    Ikeda, Y; Kobayashi, N; Kondo, S; Yasui, C; Kuzmenko, P J; Tokoro, H; Terada, H

    2009-08-12T23:59:59.000Z

    We measure the internal attenuation of bulk crystals of CVD-ZnS, CVD-ZnSe, Si, and GaAs, in the short near-infrared (sNIR) region to evaluate the possibility of astronomical immersion gratings with those high refractive index materials. We confirm that multispectral grade CVD-ZnS and CVD-ZnSe are best suited for the immersion gratings, with the smallest internal attenuation of {alpha}{sub att} = 0.01-0.03 cm{sup -1} among the major candidates. The measured attenuation is roughly in proportion to {lambda}{sup -2}, suggesting it is dominated by bulk scattering due to the polycrystalline grains rather than by absorption. The total transmittance in the immersion grating is estimated to be at least > 80 %, even for the spectral resolution of R = 300,000. Two potential problems, the scattered light by the bulk material and the degradation of the spectral resolution due to the gradient illumination in the diffracted beam, are investigated and found to be negligible for usual astronomical applications. Since the remaining problem, the difficulty of cutting grooves on CVD-ZnS and CVD-ZnSe, has recently been overcome by the nanoprecision fly-cutting technique, ZnS and ZnSe immersion gratings for astronomy can be technically realized.

  12. Experimental evidence of V{sub O}?Zn{sub i} complex to be intrinsic donor in bulk ZnO

    SciTech Connect (OSTI)

    Asghar, M.; Mahmood, K. [Department of Physics, The Islamia University of Bahawalpur 63100 (Pakistan); Hasan, M.-A; Tsu, R.; Ferguson, I. T. [Department of Electrical and Computer Engineering, University of North Carolina Charlotte, NC 28223 (United States)

    2014-02-21T23:59:59.000Z

    Theoretical evidence of V{sub O}?Zn{sub i} to be a native donor in bulk ZnO has been under debate. To resolve the issue, we annealed several pieces of as grown zinc rich n-type ZnO thin film having N{sub D} ? 3.26 10{sup 17} cm{sup ?3} grown by molecular beam epitaxy on Si (001) substrate in oxygen environment at 500C 800C, keeping a step of 100C for one hour, each. Room temperature Hall measurements demonstrated that free donor concentration decreased exponentially and Arrhenius plot yielded activation energy to be 1.20.02 eV. This value is in an agreement with the theoretically reported activation energy of V{sub O}?Zn{sub i} donor complex in ZnO.

  13. Acceptors in ZnO nanocrystals S. T. Teklemichael,1

    E-Print Network [OSTI]

    McCluskey, Matthew

    as a buffer layer for growth of GaN-based devices,2 as a transparent conductive oxide Ref. 3 in solar cells,4- drate Zn CH3COO 2·2H2O and sodium hydrogen carbon- ate NaHCO3 are reacted at 200 °C for 3 h in an open cooling down to low tempera- ture. Electron paramagnetic resonance EPR measurements were carried out

  14. Magnetism in undoped ZnS studied from density functional theory

    SciTech Connect (OSTI)

    Xiao, Wen-Zhi, E-mail: xiaowenzhi@hnu.edu.cn, E-mail: llwang@hun.edu.cn; Rong, Qing-Yan; Xiao, Gang [Department of Physics and Mathematics, Hunan Institute of Engineering, Xiangtan 411104 (China); Wang, Ling-ling, E-mail: xiaowenzhi@hnu.edu.cn, E-mail: llwang@hun.edu.cn [School of Physics and Microelectronics and Key Lab for Micro-Nano Physics and Technology of Hunan Province, Hunan University, Changsha 410082 (China); Meng, Bo [College of Physics and Electronic Engineering, Caili University, Kaili 556011 (China)

    2014-06-07T23:59:59.000Z

    The magnetic property induced by the native defects in ZnS bulk, thin film, and quantum dots are investigated comprehensively based on density functional theory within the generalized gradient approximation + Hubbard U (GGA?+?U) approach. We find the origin of magnetism is closely related to the introduction of hole into ZnS systems. The relative localization of S-3p orbitals is another key to resulting in unpaired p-electron, due to Hund's rule. For almost all the ZnS systems under study, the magnetic moment arises from the S-dangling bonds generated by Zn vacancies. The charge-neutral Zn vacancy, Zn vacancy in 1? charge sate, and S vacancy in the 1+ charge sate produce a local magnetic moment of 2.0, 1.0, and 1.0??{sub B}, respectively. The Zn vacancy in the neutral and 1? charge sates are the important cause for the ferromagnetism in ZnS bulk, with a Curie temperature (T{sub C}) above room temperature. For ZnS thin film with clean (111) surfaces, the spins on each surface are ferromagnetically coupled but antiferromagnetically coupled between two surfaces, which is attributable to the internal electric field between the two polar (111) surfaces of the thin film. Only surface Zn vacancies can yield local magnetic moment for ZnS thin film and quantum dot, which is ascribed to the surface effect. Interactions between magnetic moments on S-3p states induced by hole-doping are responsible for the ferromagnetism observed experimentally in various ZnS samples.

  15. Supporting information for: Na-doped p-type ZnO , Faxian Xiu2

    E-Print Network [OSTI]

    Yang, Zheng

    S1 Supporting information for: Na-doped p-type ZnO microwires Wei Liu1* , Faxian Xiu2 , Ke Sun1 flow was switched to argon followed by cooling to room temperature. After the growth, high-density Zn distribution of the Na Doped ZnO microwire 1.3 EDX line scans spectra #12;S3 Figure S3 a) a typical TEM image

  16. Co-adapted coupling Random walk on Zn 2 Random walk on Gn

    E-Print Network [OSTI]

    Co-adapted coupling Random walk on Zn 2 Random walk on Gn d Optimal co-adapted coupling Stephen Connor sbc502@york.ac.uk #12;Co-adapted coupling Random walk on Zn 2 Random walk on Gn d Outline 1 Co-adapted coupling 2 Simple random walk on the hypercube, Zn 2 3 Simple random walk on Gn d #12;Co-adapted coupling

  17. Radiant cooling research scoping study

    E-Print Network [OSTI]

    Moore, Timothy; Bauman, Fred; Huizenga, Charlie

    2006-01-01T23:59:59.000Z

    www.Zurn.com PAGE 35 Radiant Cooling Research Scoping Study1988. Radiant Heating and Cooling, Displacement VentilationHeat Recovery and Storm Water Cooling: An Environmentally

  18. Narrow Bandgap in beta-BaZn2As2 and Its Chemical Origins

    E-Print Network [OSTI]

    Xiao, Zewen; Ueda, Shigenori; Toda, Yoshitake; Ran, Fan-Yong; Guo, Jiangang; Lei, Hechang; Matsuishi, Satoru; Hosono, Hideo; Kamiya, Toshio

    2015-01-01T23:59:59.000Z

    Beta-BaZn2As2 is known to be a p-type semiconductor with the layered crystal structure similar to that of LaZnAsO, leading to the expectation that beta-BaZn2As2 and LaZnAsO have similar bandgaps; however, the bandgap of beta-BaZn2As2 (previously-reported value ~0.2 eV) is one order of magnitude smaller than that of LaZnAsO (1.5 eV). In this paper, the reliable bandgap value of beta-BaZn2As2 is determined to be 0.23 eV from the intrinsic region of the tem-perature dependence of electrical conductivity. The origins of this narrow bandgap are discussed based on the chemi-cal bonding nature probed by 6 keV hard X-ray photoemission spectroscopy, hybrid density functional calculations, and the ligand theory. One origin is the direct As-As hybridization between adjacent [ZnAs] layers, which leads to a secondary splitting of As 4p levels and raises the valence band maximum. The other is that the non-bonding Ba 5dx2-y2 orbitals form unexpectedly deep conduction band minimum (CBM) in beta-BaZn2As2 although the CBM of L...

  19. Optical and morphological properties of graphene sheets decorated with ZnO nanowires via polyol enhancement

    SciTech Connect (OSTI)

    Sharma, Vinay, E-mail: winn201@gmail.com; Rajaura, Rajveer Singh, E-mail: winn201@gmail.com [Centre for Converging Technologies, University of Rajasthan, Jaipur - 302004 (India); Sharma, Preetam K.; Srivastava, Subodh; Vijay, Y. K. [Department of Physics, Thin Film and Membrane Science Lab., University of Rajasthan, Jaipur - 302004 (India); Sharma, S. S. [Department of Physics, Govt. Women Engineering College, Ajmer- 305002 (India)

    2014-04-24T23:59:59.000Z

    Graphene-ZnO nanocomposites have proven to be very useful materials for photovoltaic and sensor applications. Here, we report a facile, one-step in situ polymerization method for synthesis of graphene sheets randomly decorated with zinc oxide nanowires using ethylene glycol as solvent. We have used hydrothermal treatment for growth of ZnO nanowires. UV-visible spectra peak shifting around 288nm and 307 nm shows the presence of ZnO on graphene structure. Photoluminiscence spectra (PL) in 400nm-500nm region exhibits the luminescence quenching effect. Scanning electron microscopy (SEM) image confirms the growth of ZnO nanowires on graphene sheets.

  20. Hidden Ferromagnetic Secondary Phases in Cobalt-doped ZnO Epitaxial...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ZnO Epitaxial Thin Films. Abstract: The quest to discover a dilute magnetic semiconductor which is ferromagnetic at room temperature has led to extensive research on...

  1. Structure of {sup 81}Ga populated from the {beta}{sup -} decay of {sup 81}Zn

    SciTech Connect (OSTI)

    Paziy, V.; Mach, H.; Fraile, L. M.; Olaizola, B.; Udias, J. M. [Grupo de Fisica Nuclear, Universidad Complutense, Madrid (Spain); Aprahamian, A.; Bucher, B. [Department of Physics, University of Notre Dame (United States); Bernards, C. [Institut fuer Kernphysik, Koeln, Germany. and Wright Nuclear Structure Laboratory, Yale University, New Haven, CT-06520 (United States); Briz, J. A. [Instituto de Estructura de la Materia, CSIC, Madrid (Spain); Chiara, C. J. [Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland, USA. and Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Dlouhy, Z. [Nuclear Physics Institute of the ASCR, Rez (Czech Republic); Gheorghe, I.; Ghita, D.; Lica, R.; Marginean, N.; Marginean, R.; Stanoiu, M.; Stroe, L. [National Institute for Physics and Nuclear Engineering, Magurele (Romania); Hoff, P. [Department of Chemistry, University of Oslo, Oslo (Norway); Koester, U. [Institut Laue Langevin, 6 Rue Jules Horowitz, F-38042 Grenoble Cedex 9 (France); and others

    2013-06-10T23:59:59.000Z

    We report on the results of the {beta}-decay of {sup 81}Zn. The experiment was performed at the CERN ISOLDE facility in the framework of a systematic ultra-fast timing investigation of neutron-rich nuclei populated in the decay of Zn. The present analysis included {beta}-gated {gamma}-ray singles and {gamma}-{gamma} coincidences from the decay of {sup 81}Zn to {sup 81}Ga and leads to a new and much more extensive level scheme of {sup 81}Ga. A new half-life of {sup 81}Zn is provided.

  2. Green synthesis of graphene nanosheets/ZnO composites and electrochemical properties

    SciTech Connect (OSTI)

    Wang Jun, E-mail: zhqw1888@sohu.com [College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, Harbin 150001 (China); Gao Zan [College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, Harbin 150001 (China); Li Zhanshuang; Wang Bin; Yan Yanxia; Liu Qi [College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Mann, Tom [Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, Harbin 150001 (China); Zhang Milin [College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, Harbin 150001 (China); Jiang Zhaohua [College of Chemical Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2011-06-15T23:59:59.000Z

    A green and facile approach was demonstrated to prepare graphene nanosheets/ZnO (GNS/ZnO) composites for supercapacitor materials. Glucose, as a reducing agent, and exfoliated graphite oxide (GO), as precursor, were used to synthesize GNS, then ZnO directly grew onto conducting graphene nanosheets as electrode materials. The small ZnO particles successfully anchored onto graphene sheets as spacers to keep the neighboring sheets separate. The electrochemical performances of these electrodes were analyzed by cyclic voltammetry, electrochemical impedance spectrometry and chronopotentiometry. Results showed that the GNS/ZnO composites displayed superior capacitive performance with large capacitance (62.2 F/g), excellent cyclic performance, and maximum power density (8.1 kW/kg) as compared with pure graphene electrodes. Our investigation highlight the importance of anchoring of small ZnO particles on graphene sheets for maximum utilization of electrochemically active ZnO and graphene for energy storage application in supercapacitors. - Graphical abstract: Glucose was used to synthesize GNS, then ZnO directly grew onto conducting graphene nanosheets as electrode materials for supercapacitor. Results showed that the composites have superior capacitive performance. Highlights: > Graphene nanosheets were synthesized via using glucose as a reducing agent. > The reductant and the oxidized product are environmentally friendly. > ZnO grew onto conducting graphene sheets keeping neighboring sheets separate. > The structure improves the contact between the electrode and the electrolyte. > Results showed that these composites have good electrochemical property.

  3. Phase diagram, crystal chemistry and thermoelectric properties of compounds in the Ca?Co?Zn?O system

    SciTech Connect (OSTI)

    Wong-Ng, W.; Luo, T.; Xie, W.; Tang, W.H.; Kaduk, J.A.; Huang, Q.; Yan, Y.; Chattopadhyay, S.; Tang, X.; Tritt, T. (IIT); (Clemson); (NIST); (Maryland); (Zhejiang); (Wuhan)

    2011-11-17T23:59:59.000Z

    In the Ca-Co-Zn-O system, we have determined the tie-line relationships and the thermoelectric properties, solid solution limits, and structures of two low-dimensional cobaltite series, Ca{sub 3}(Co, Zn){sub 4}O{sub 9-z} and Ca{sub 3}(Co,Zn){sub 2}O{sub 6-z} at 885 C in air. In Ca{sub 3}(Co,Zn){sub 4}O{sub 9-z}, which has a misfit layered structure, Zn was found to substitute in the Co site to a limit of Ca{sub 3}(Co{sub 3.8}Zn{sub 0.2})O{sub 9-z}. The compound Ca{sub 3}(Co,Zn){sub 2}O{sub 6-z} (n=1 member of the homologous series, Ca{sub n+2}(Co,Zn)n(Co,Zn)'O{sub 3n+3-z}) consists of one-dimensional parallel (Co,Zn){sub 2}O{sub 6}{sup 6-} chains that are built from successive alternating face-sharing (Co,Zn)O{sub 6} trigonal prisms and 'n' units of (Co,Zn)O{sub 6} octahedra along the hexagonal c-axis. Zn substitutes in the Co site of Ca{sub 3}Co{sub 2}O{sub 6} to a small amount of approximately Ca{sub 3}(Co{sub 1.95}Zn{sub 0.05})O{sub 6-z}. In the ZnO-CoO{sub z} system, Zn substitutes in the tetrahedral Co site of Co{sub 3}O{sub 4} to the maximum amount of (Co{sub 2.49}Zn{sub 0.51})O{sub 4-z} and Co substitutes in the Zn site of ZnO to (Zn{sub 0.94}Co{sub 0.06})O. The crystal structures of (Co{sub 2.7}Zn{sub 0.3})O{sub 4-z}, (Zn{sub 0.94}Co{sub 0.06})O, and Ca{sub 3}(Co{sub 1.95} Zn{sub 0.05})O{sub 6-z} are described. Despite the Ca{sub 3}(Co, Zn){sub 2}O{sub 6-z} series having reasonably high Seebeck coefficients and relatively low thermal conductivity, the electrical resistivity values of its members are too high to achieve high figure of merit, ZT.

  4. Visualization of Peroxynitrite-Induced Changes of Labile Zn[superscript 2+] in the Endoplasmic Reticulum with Benzoresorufin-based Fluorescent Probes

    E-Print Network [OSTI]

    Lin, Wei

    Zn[superscript 2+] plays essential roles in biology, and the homeostasis of Zn[superscript 2+] is tightly regulated in all cells. Subcellular distribution and trafficking of labile Zn[superscript 2+], and its inter-relation ...

  5. Structural Stability and Defect Energetics of ZnO from Diffusion Quantum Monte Carlo

    SciTech Connect (OSTI)

    Santana Palacio, Juan A [ORNL; Krogel, Jaron T [ORNL; Kim, Jeongnim [ORNL; Kent, Paul R [ORNL; Reboredo, Fernando A [ORNL

    2015-01-01T23:59:59.000Z

    We have applied the many-body ab-initio diffusion quantum Monte Carlo (DMC) method to study Zn and ZnO crystals under pressure, and the energetics of the oxygen vacancy, zinc interstitial and hydrogen impurities in ZnO. We show that DMC is an accurate and practical method that can be used to characterize multiple properties of materials that are challenging for density functional theory approximations. DMC agrees with experimental measurements to within 0.3 eV, including the band-gap of ZnO, the ionization potential of O and Zn, and the atomization energy of O2, ZnO dimer, and wurtzite ZnO. DMC predicts the oxygen vacancy as a deep donor with a formation energy of 5.0(2) eV under O-rich conditions and thermodynamic transition levels located between 1.8 and 2.5 eV from the valence band maximum. Our DMC results indicate that the concentration of zinc interstitial and hydrogen impurities in ZnO should be low under n-type, and Zn- and H-rich conditions because these defects have formation energies above 1.4 eV under these conditions. Comparison of DMC and hybrid functionals shows that these DFT approximations can be parameterized to yield a general correct qualitative description of ZnO. However, the formation energy of defects in ZnO evaluated with DMC and hybrid functionals can differ by more than 0.5 eV.

  6. HIGH TEMPERATURE LATTICE PARAMETERS OF ZnSiP2, ZnGeP2 AND CdGeP2 A. MILLER (*), R. G. HUMPHREYS and B. CHAPMAN

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    HIGH TEMPERATURE LATTICE PARAMETERS OF ZnSiP2, ZnGeP2 AND CdGeP2 A. MILLER (*), R. G. HUMPHREYS parameters from room temperature to 1.100 "C have been studied for the chalcopyrite semiconductors, ZnSiP2, ZnGeP2 and CdGeP2 using a high temperature X-ray camera. All three compounds show an increase

  7. Temperature-dependent photoluminescence of CdZnO thin films grown by molecular-beam epitaxy

    E-Print Network [OSTI]

    Yang, Zheng

    performed on three typical CdZnO samples having pure wurtzite, pure rocksalt, and wurtziterocksalt mixture and analyzed based on the variable-temperature PL studies of typical wurtzite (wz) CdZnO, rocksalt (rs) Cd

  8. Surface chemistry controls crystallinity of ZnSnanoparticles

    SciTech Connect (OSTI)

    Gilbert, Benjamin; Huang, Feng; Lin, Zhang; Goodell, Carmen; Zhang, Hengzhong; Banfield Jillian F.

    2005-12-20T23:59:59.000Z

    Combined small-angle and high energy wide-angle x-ray scattering measurements of nanoparticle size and structure permit interior strain and disorder to be directly observed in the real-space pair distribution function (PDF). PDF analysis showed that samples of ZnS nanoparticle with similar mean diameters (3.2-3.6 nm) but synthesized and treated differently possess a dramatic range of interior disorder. We used Fourier transform infra-red spectroscopy to detect the surface species and the nature of surface chemical interactions. Our results suggest that there is a direct correlation between the strength of surface-ligand interactions and interior crystallinity.

  9. Structural Phase Transition in AuZn Alloys

    SciTech Connect (OSTI)

    Winn,B.L.; Shapiro, S.M.; Lashley, J.C.; Opeil, C.; Ratcliff, W.

    2009-05-03T23:59:59.000Z

    AuxZn1-x alloys undergo a shape memory martensitic transformation whose temperature and nature (continuous or discontinuous) is strongly composition dependent. Neutron diffraction experiments were performed on single crystals of x=50 and 52 to explore the structural changes occurring at the transition temperature. A transverse modulation with wavevector q0=(1/3,1/3,0) develops below the transition temperature, with no observable change in lattice parameter. However, the Bragg peak width shows a broadening suggesting an unresolved rhombohedral distortion similar to what has been observed in NiTi-Fe alloys.

  10. Diamond-machined ZnSe immersion grating for NIR high-resolution spectroscopy

    SciTech Connect (OSTI)

    Ikeda, Y; Kobayashi, N; Kuzmenko, P J; Little, S L; Yasui, C; Kondo, S; Minami, A; Motohara, K

    2008-07-25T23:59:59.000Z

    ZnSe immersion gratings (n {approx} 2.45) provide the possibility of high-resolution spectroscopy for the near-infrared (NIR) region. Since ZnSe has a lower internal attenuation than other NIR materials, it is most suitable for immersion grating, particularly in short NIR region (0.8-1.4 {micro}m). We are developing an extremely high-resolution spectrograph with {lambda}/{Delta}{lambda} = 100,000, WINERED, customized for the short NIR region, using ZnSe (or ZnS) immersion grating. However, it had been very difficult to make fine grooves on ZnSe substrate with a small pitch of less than 50 {micro}m because ZnSe is a soft/brittle material. We have overcome this problem and successfully machined sharp grooves with fine pitch on ZnSe substrates by nano precision fly-cutting technique at LLNL. The optical testing of the sample grating with HeNe laser shows an excellent performance: the relative efficiency more than 87.4 % at 0.633 {micro}m for a classical grating configuration. The diffraction efficiency when used as an immersion grating is estimated to be more than 65 % at 1 {micro}m. Following this progress, we are about to start machining a grating on a large ZnSe prism with an entrance aperture of 23mm x 50mm and the blaze angle of 70{sup o}.

  11. Thickness influence on surface morphology and ozone sensing properties of nanostructured ZnO transparent

    E-Print Network [OSTI]

    , 71004 Heraklion, Crete, Greece Available online 19 January 2006 Abstract Transparent zinc oxide (Zn Keywords: Zinc oxide; PLD; AFM; Ozone 1. Introduction Zinc oxide (ZnO) is an n-type semiconductor devices [3], varistors, planar optical waveguides [4], transparent electrodes [5,6], ultraviolet

  12. DOI: 10.1002/adma.200702781 Aerogel Templated ZnO Dye-Sensitized Solar Cells**

    E-Print Network [OSTI]

    as substructure templates. The aerogel templates are coated with ZnO via atomic layer deposition (ALD) to yieldDOI: 10.1002/adma.200702781 Aerogel Templated ZnO Dye-Sensitized Solar Cells** By Thomas W. Hamann produced from coating tem- plates of high aspect ratio substructures, exhibiting initial efficiencies up

  13. Growth of anisotropic one-dimensional ZnS nanostructures{ Daniel Moore and Zhong L. Wang*

    E-Print Network [OSTI]

    Wang, Zhong L.

    with wurtzite ZnS. This feature article covers the ZnS one-dimensional nanostructures that have been synthesized crystal structure known as the wurtzite structure (Fig. 1). This transformation has been shown to occur at 1020 uC. The zinc blend and wurtzite structures are very similar. The stacking sequence of the close

  14. ClebschGordan coefficients for scattering tensors in ZnO and other

    E-Print Network [OSTI]

    Nabben, Reinhard

    ClebschGordan coefficients for scattering tensors in ZnO and other wurtzite semiconductors Herbert, and A are investigated in wurtzite ZnO. The knowledge of the selection rules is required for the determination, in non-centro-symmetric crystals (zinc blende and wurtzite) the strain tensor and induced electric fields

  15. Relative stability of nanosized wurtzite and graphitic ZnO from density functional theory

    E-Print Network [OSTI]

    Melnik, Roderick

    Relative stability of nanosized wurtzite and graphitic ZnO from density functional theory Bin Wen to determine the relative stability of wurtzite and graphitic phases of ZnO nanostructures. Our results the threshold number, the relative stability of the wurtzite phase is observed. Finally, we discuss

  16. Reduction of the transverse effective charge of optical phonons in ZnO under pressure

    E-Print Network [OSTI]

    Nabben, Reinhard

    ; accepted 18 May 2010; published online 9 June 2010 From Raman scattering on a-plane wurtzite ZnO crystalsO is the wurtzite structure. Recently, the me- chanical properties of ZnO have been investigated up to 60 GPa.4 The initial wurtzite phase was observed to transform to the rocksalt structure around 9.1 GPa with a large

  17. Zinc-blende ZnO and its role in nucleating wurtzite tetrapods and twinned nanowires

    E-Print Network [OSTI]

    Wang, Zhong L.

    Zinc-blende ZnO and its role in nucleating wurtzite tetrapods and twinned nanowires Yong Ding of wurtzite WZ ZnO tetrapods. The formation of the wurtzite 0113 twined nanowires is proposed based on the ZB core. Simple bonding density calculation shows that the wurtzite nanowires with 0110 side surfaces

  18. Wurtzite ZnS nanosaws produced by polar surfaces Daniel Moore a

    E-Print Network [OSTI]

    Wang, Zhong L.

    Wurtzite ZnS nanosaws produced by polar surfaces Daniel Moore a , Carsten Ronning a,b , Christopher December 2003 Published online: 10 January 2004 Abstract Wurtzite structured ZnS nanoribbons have been for electronic and optoelectronic nanodevices [12,13]. Zinc blend and wurtzite structures are the two most

  19. Water adsorption on stepped ZnO surfaces from MD simulation David Raymand a

    E-Print Network [OSTI]

    Goddard III, William A.

    Water adsorption on stepped ZnO surfaces from MD simulation David Raymand a , Adri C.T. van Duin b Keywords: Zinc oxide Water Solidgas interfaces Construction and use of effective interatomic interactions force-field for use in molecular dynamics simulations of the ZnO water system. The force

  20. Rapid degradation of CdSe/ZnS colloidal quantum dots exposed to gamma irradiation

    E-Print Network [OSTI]

    New Mexico, University of

    Rapid degradation of CdSe/ZnS colloidal quantum dots exposed to gamma irradiation Nathan J. Withers are reported. Optical degradation is evaluated by tracking the dependence of photoluminescence intensity on irradiation dose. CdSe/ZnS quantum dots show poor radiation hardness, and severely degrade after less than 20

  1. Structure and magnetic properties of rf thermally plasma synthesized Mn and MnZn ferrite nanoparticles

    E-Print Network [OSTI]

    McHenry, Michael E.

    Structure and magnetic properties of rf thermally plasma synthesized Mn and Mn­Zn ferrite has previously been shown to be a viable route to producing nanocrystalline magnetite and Ni ferrite nanoparticles. In this work nanocrystalline powders of Mn and Mn­Zn ferrites have been synthesized using a 50 k

  2. An Analysis of Mn-Zn Ferrite Microstructure by Impedance Spectroscopy, STEM and EDS Characterisations.

    E-Print Network [OSTI]

    Boyer, Edmond

    An Analysis of Mn-Zn Ferrite Microstructure by Impedance Spectroscopy, STEM and EDS.loyau@satie.ens-cachan.fr Abstract AC resistivity measurement results on Mn-Zn sintered ferrite were analyzed in the 0.1-500 MHz of the main limitations in frequency increase is the energy dissipations by losses in ferrites that produce

  3. Microstructural Evolution Model of the Sintering Behavior and Magnetic Properties of NiZn Ferrite Nanoparticles

    E-Print Network [OSTI]

    McHenry, Michael E.

    Microstructural Evolution Model of the Sintering Behavior and Magnetic Properties of NiZn Ferrite jlwoods@andrew.cmu.edu, c SCalvin@slc.edu, d jhuth@Spang.co, e mm7g@andrew.cmu.edu Keywords: Ferrite, nanoparticle, sintering, microstructure. Abstract. The sintering of RF plasma synthesized NiZn ferrite

  4. THE LIND-LEHMER CONSTANT FOR Zn DILUM DESILVA AND CHRISTOPHER PINNER

    E-Print Network [OSTI]

    Pinner, Christopher

    THE LIND-LEHMER CONSTANT FOR Zn p DILUM DESILVA AND CHRISTOPHER PINNER Abstract. We determine the Lind Lehmer constant for groups of the form Zn p . 1. Introduction Let G be a compact abelian group of integral combinations of characters, Lind [6] defines a logarithmic Mahler measure of f over G m(f) = m

  5. Fabrication of Microfibre-nanowire Junction Arrays of ZnO/SnO2 Composite

    E-Print Network [OSTI]

    Iglic, Ales

    nanocomposite sensitized with a D35-cpdt dye was investigated. A dye-sensitized solar cell (DSSC) with a Zn discussed. Keywords ZnO/SnO2 Nanocomposite, Dye-sensitized Solar Cell, Nanostructured Surfaces 1O/SnO2 nanocomposite photoanode based on a cobalt electrolyte achieved a solar-to-electricity conversion

  6. DOI: 10.1002/adfm.200701073 Polydisperse Aggregates of ZnO Nanocrystallites: A Method

    E-Print Network [OSTI]

    Cao, Guozhong

    -Conversion-Efficiency Enhancement in Dye-Sensitized Solar Cells** By Qifeng Zhang, Tammy P. Chou, Bryan Russo, Samson A. Jenekhe, and Guozhong Cao* 1. Introduction ZnO-based dye-sensitized solar cells (DSSCs) have attrac- ted considerable a relatively efficient dye-sensitized ZnO solar cell with a conversion efficiency of $3

  7. A Novel Electrodeposition Process for Plating Zn-Ni-Cd Alloys Hansung Kim,a,

    E-Print Network [OSTI]

    Popov, Branko N.

    A Novel Electrodeposition Process for Plating Zn-Ni-Cd Alloys Hansung Kim,a, * Branko N. Popov Sciences Center, Albuquerque, New Mexico 87185-0834, USA Zn-Ni-Cd alloy was electrodeposited from in the literature.7-9 Typical nickel composition in the alloy is approximately 10%, and any further increase

  8. Recycling ZnTe, CdTe, and Other Compound Semiconductors by Ambipolar Electrolysis

    E-Print Network [OSTI]

    Osswald, Sebastian

    The electrochemical behavior of ZnTe and CdTe compound semiconductors dissolved in molten ZnCl[subscript 2] and equimolar CdCl[subscript 2]KCl, respectively, was examined. In these melts dissolved Te is present as the ...

  9. Coplanar grid CdZnTe detectors for space science applications Benjamin W. Sturm*a

    E-Print Network [OSTI]

    He, Zhong

    Coplanar grid CdZnTe detectors for space science applications Benjamin W. Sturm*a , Zhong Hea of the latest coplanar grid CdZnTe detectors, which use the third- generation coplanar grid design into the material properties as well as the charge induction uniformity of the detector. Keywords: coplanar grid, Cd

  10. Effect of Zinc (Zn (II)) on the Adsorption Mechanisms of Arsenate (As (V)) at the

    E-Print Network [OSTI]

    Sparks, Donald L.

    Effect of Zinc (Zn (II)) on the Adsorption Mechanisms of Arsenate (As (V)) at the Goethite of As and Zn adsorption on goethite was investigated over a pH range of 3 to 10. X-ray absorption fine adsorption on goethite. The macroscopic data show that As adsorption on goethite was envelope

  11. Improvement of electroluminescence performance by integration of ZnO nanowires and single-crystalline films on ZnO/GaN heterojunction

    SciTech Connect (OSTI)

    Shi, Zhifeng; Zhang, Yuantao, E-mail: zhangyt@jlu.edu.cn; Cui, Xijun; Wu, Bin; Zhuang, Shiwei; Yang, Fan; Zhang, Baolin; Du, Guotong [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Qianjin Street 2699, Changchun 130012 (China); Yang, Xiaotian [School of Electrical and Electronic Information, Jilin Institute of Architecture and Civil Engineering, Changchun 130118 (China)

    2014-03-31T23:59:59.000Z

    Heterojunction light-emitting diodes based on n-ZnO nanowires/ZnO single-crystalline films/p-GaN structure have been demonstrated for an improved electroluminescence performance. A highly efficient ultraviolet emission was observed under forward bias. Compared with conventional n-ZnO/p-GaN structure, high internal quantum efficiency and light extraction efficiency were simultaneously considered in the proposed diode. In addition, the diode can work continuously for ?10?h with only a slight degradation in harsh environments, indicating its good reliability and application prospect in the future. This route opens possibilities for the development of advanced nanoscale devices in which the advantages of ZnO single-crystalline films and nanostructures can be integrated together.

  12. Strain effects and band parameters in MgO, ZnO, and CdO Qimin Yan,1

    E-Print Network [OSTI]

    deformation potentials for MgO, ZnO, and CdO in the wurtzite phase. To overcome the limitations of density equilibrium crystal structure. While ZnO crystal- izes in the wurtzite phase, MgO and CdO adopt the rocksalt phase. In spite of this complication wurtzite Zn1-xMgxO and Zn1-xCdxO alloys with low Mg or Cd

  13. X-ray diffraction study of thermal stress relaxation in ZnO films deposited by magnetron sputtering

    E-Print Network [OSTI]

    silicon substrate: ZnO and ZnO encapsulated into Si3N4 layers. We showed that both as-deposited ZnO films with Si3N4 encapsulation. The observations show that Si3N4 films lying on both sides of the ZnO film play in many application domains such as ultraviolet detectors, light-emitting diodes, solar cells. As a II

  14. SrAgZn and EuAgZn with KHg{sub 2}-type structureStructure, magnetic properties, and {sup 151}Eu Mssbauer spectroscopy

    SciTech Connect (OSTI)

    Gerke, Birgit; Rodewald, Ute Ch.; Niehaus, Oliver; Pttgen, Rainer, E-mail: pottgen@uni-muenster.de

    2013-07-15T23:59:59.000Z

    Samples of SrAgZn and EuAgZn were synthesized by reaction of the elements in sealed tantalum crucibles. Both structures were refined on the basis of single crystal X-ray diffractometer data: KHg{sub 2}-type, Imma, a=476.7(1), b=780.9(2), c=810.1(2) pm, R{sub 1}/wR{sub 2}=0.0189/0.0119, 381 F values for SrAg{sub 1.12}Zn{sub 0.88} and a=474.43(9), b=760.8(2), c=799.0(2) pm, R{sub 1}/wR{sub 2}=0.0226/0.0483, 370 F values for EuAg{sub 1.17}Zn{sub 0.83} with 13 variables per refinement. Silver and zinc are randomly distributed on the Hg position and build up three-dimensional networks. EuAgZn shows ferromagnetic ordering at 29(1) K. In the temperature range from 75 to 300 K the sample shows CurieWeiss behaviour with ?{sub eff}=7.87(1) ?{sub B}/Eu atom and ?{sub P}=37.1(1) K, indicating divalent europium. {sup 151}Eu Mssbauer spectroscopic measurements confirmed the divalent state with an isomer shift of ?9.31 mm/s at 78 K. Temperature dependent {sup 151}Eu data show first magnetic hyperfine field splitting at 25 K and a saturated magnetization of 17 T at 5.2 K. The temperature dependence can be described by an S=7/2 Brillouin function. - Graphical abstract: The near neighbor coordination of the strontium and europium atoms in SrAg{sub 1.12}Zn{sub 0.88}, EuAg{sub 1.17}Zn{sub 0.83}, and EuAuZn. - Highlights: Synthesis of new intermetallic zinc compounds SrAgZn and EuAgZn. Ferromagnetic ordering of EuAgZn at 29 K. Magnetic hyperfine field splitting in the {sup 151}Eu Mssbauer spectrum.

  15. Luminescence properties of ZnO layers grown on Si-on-insulator substrates

    SciTech Connect (OSTI)

    Kumar, Bhupendra; Gong, Hao; Vicknesh, S.; Chua, S. J.; Tripathy, S. [Department of Materials Science and Engineering, National University of Singapore, 119260 Singapore (Singapore); Institute of Materials Research and Engineering, 3 Research Link, 117602 Singapore (Singapore)

    2006-10-02T23:59:59.000Z

    The authors report on the photoluminescence properties of polycrystalline ZnO thin films grown on compliant silicon-on-insulator (SOI) substrates by radio frequency magnetron sputtering. The ZnO thin films on SOI were characterized by micro-Raman and photoluminescence (PL) spectroscopy. The observation of E{sub 2}{sup high} optical phonon mode near 438 cm{sup -1} in the Raman spectra of the ZnO samples represents the wurtzite crystal structure. Apart from the near-band-edge free exciton (FX) transition around 3.35 eV at 77 K, the PL spectra of such ZnO films also showed a strong defect-induced violet emission peak in the range of 3.05-3.09 eV. Realization of such ZnO layers on SOI would be useful for heterointegration with SOI-based microelectronics and microelectromechanical systems.

  16. Optical and phonon properties of ZnO:CuO mixed nanocomposite

    SciTech Connect (OSTI)

    Udayabhaskar, R.; Karthikeyan, B., E-mail: bkarthik@nitt.edu [Department of Physics, National Institute of Technology, Tiruchirappalli 620 015 (India)

    2014-04-21T23:59:59.000Z

    Optical and phonon properties of ZnO:CuO nanocrystals which are prepared through sol-gel method are reported here. From X-ray diffraction studies, observed that Cu doping replaces the Zn and also forms secondary phase. Optical absorption spectral studies shows that the exciton and plasmon related bands of ZnO and CuO phase, respectively. Fluorescence studies of the prepared samples shows that green emission from ZnO is completely depleted and the same is attributed to CuO Plasmon. Raman spectral studies reveal that secondary phase (impurity) induced profile changes in 1LO and E{sub 2High} modes. Asymmetry in peak shape is analyzed using Fano profile with the combination of Lorentzian profile. Moreover, the monotonic increase of Fano factor and full width at half maxima is hopefully attributed to the continuum arises by the plasmons of Cu-O phase in ZnO nanosystem.

  17. Heteroepitaxial ZnO films on diamond: Optoelectronic properties and the role of interface polarity

    SciTech Connect (OSTI)

    Schuster, Fabian, E-mail: Fabian.Schuster@wsi.tum.de; Hetzl, Martin; Garrido, Jose A.; Stutzmann, Martin [Walter Schottky Institut, Technische Universitt Mnchen, Am Coulombwall 4, 85748 Garching (Germany); Magn, Cesar [Laboratorio de Microscopas Avanzadas (LMA) - Instituto de Nanociencia de Aragon (INA) and Departamento de Fsica de la Materia Condensada, Universidad de Zaragoza, 50018 Zaragoza (Spain); Fundacin ARAID, 50018 Zaragoza (Spain); Arbiol, Jordi [Institut de Cincia de Materials de Barcelona, ICMAB-CSIC, Campus de la UAB, 08193 Bellaterra, CAT (Spain); Instituci Catalana de Recerca i Estudis Avanats (ICREA), 08010 Barcelona, CAT (Spain)

    2014-06-07T23:59:59.000Z

    We demonstrate the growth of heteroepitaxial ZnO films on (110) diamond substrates by molecular beam epitaxy and report on a major advance in structural quality, as confirmed by XRD and high-resolution TEM measurements. The growth direction is found to be along the polar c-axis with Zn-polarity, deduced from annular bright-field scanning transmission electron microscopy imaging. This is important information, as simulations of the electronic band structure reveal the ZnO polarity to dominate the electronic structure of the interface: the formation of a two-dimensional electron gas on the ZnO side or a two-dimensional hole gas on the diamond side are predicted for Zn- and O-polarity, respectively. In addition, photoluminescence and absorption studies exhibit good optical properties and reveal stimulated emission for optical excitation above a threshold of 30?kW/cm{sup 2}.

  18. First-principles study of polarization in Zn1-xMgxO Andrei Malashevich* and David Vanderbilt

    E-Print Network [OSTI]

    Vanderbilt, David

    August 2006; published 4 January 2007 Wurtzite ZnO can be substituted with up to 30% MgO to form a metastable Zn1-xMgxO alloy while still retaining the wurtzite structure. Because this alloy has a larger band. INTRODUCTION Recently, much attention has been paid to wurtzite Zn1-xMgxO alloys as candidates for applications

  19. Phonon deformation potentials in wurtzite GaN and ZnO determined by uniaxial pressure dependent Raman measurements

    E-Print Network [OSTI]

    Nabben, Reinhard

    Phonon deformation potentials in wurtzite GaN and ZnO determined by uniaxial pressure dependent deformation potentials in wurtzite GaN and ZnO determined by uniaxial pressure dependent Raman measurements G online 9 February 2011 We report the phonon deformation potentials of wurtzite GaN and ZnO for all zone

  20. Effects of Cu, Zn, and S application to peach trees (Prunus persica (L.) Batsch.) on an east Texas soil

    E-Print Network [OSTI]

    Powell, Jason Cory

    1994-01-01T23:59:59.000Z

    treatment was replicated 4 times. Sulfur and Cu treatments were applied in January followed by three separate Zn foliar sprays in March, April, and May. Responses were linear between applied Zn and foliar Zn, applied S and foliar S, and applied S and leaf...

  1. Adsorption and Diffusion of Hydrogen in a New Metal-Organic Framework Material: [Zn(bdc)(ted)0.5

    E-Print Network [OSTI]

    Li, Jing

    Adsorption and Diffusion of Hydrogen in a New Metal-Organic Framework Material: [Zn(bdc)(ted)0.5 pressure of 50 bar in a recently developed metal-organic framework material, [Zn(bdc)(ted)0.5] (bdc equilibrium molecular dynamics to compute self- and transport diffusivities of hydrogen in [Zn(bdc)(ted)0.5

  2. Corrosion Protection of Steel Using Nonanomalous Ni-Zn-P Basker Veeraraghavan,* Bala Haran,** Swaminatha P. Kumaraguru,*

    E-Print Network [OSTI]

    Popov, Branko N.

    Corrosion Protection of Steel Using Nonanomalous Ni-Zn-P Coatings Basker Veeraraghavan,* Bala Haran on the corrosion resistance of the final deposit. Coatings with 16.2 wt % Zn were found to display a potential of 0 of the coating and the surface morphology. Corrosion studies in corroding media show that Ni-Zn-P coatings

  3. Stability of ZnMgO oxide in a weak alkaline solution E. Diler1,2

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    -dissolution of ZnO is negligible: indeed, both processes reduce significantly the efficiency of photocatalysisO sample. This alloy, thus, constitutes an alternative to the use of ZnO in photocatalysis applications cells, photodetectors, light emitting diodes, magnetic storage and photocatalysis. In some cases, Zn

  4. Phase transformation of ZnMoO{sub 4} by localized thermal spike

    SciTech Connect (OSTI)

    Agarwal, D. C.; Avasthi, D. K.; Kabiraj, D. [Inter-University Accelerator Center, Aruna Asaf Ali Marg, New Delhi 110067 (India); Varma, S. [Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005 (India); Kremer, Felipe; Ridgway, M. C. [Australian National University, Canberra ACT 0200 (Australia)

    2014-04-28T23:59:59.000Z

    We show that ZnMoO{sub 4} remains in stable phase under thermal annealing up to 1000?C, whereas it decomposes to ZnO and MoO{sub 3} under transient thermal spike induced by 100?MeV Ag irradiation. The transformation is evidenced by X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Thin films of ZnMoO{sub 4} were synthesized by thermal evaporation and subsequent annealing in oxygen ambient at 600?C for 4?h. XRD results show that as the irradiation fluence increases, the peak related to ZnMoO{sub 4} decreases gradually and eventually disappear, whereas peaks related to ZnO grow steadily up to fluence of 3??10{sup 12} ions/cm{sup 2} and thereafter remain stable till highest fluence. This indicates that polycrystalline ZnMoO{sub 4} film has transformed to polycrystalline ZnO thin film. The Raman lines related to ZnMoO{sub 4} are observed to have disappeared with increasing irradiation fluence. XPS results show modification in bonding and depletion of Mo from near surface region after the ion irradiation. Cross-sectional transmission electron microscopy result shows the formation of ion track of diameter 1216?nm. These results demonstrate that ion beam methods provide the means to control phase splitting of ZnMoO{sub 4} to ZnO and MoO{sub 3} within nanometric dimension along the ion track. The observation of phase splitting and Mo loss are explained in the framework of ion beam induced thermal spike formalism.

  5. Development of ZnO:Ga as an Ultrafast Scintillator

    SciTech Connect (OSTI)

    Bourret-Courchesne, E.D.; Derenzo, S.E.; Weber, M.J.

    2008-12-10T23:59:59.000Z

    We report on several methods for synthesizing the ultra-fast scintillator ZnO(Ga), and measurements of the resulting products. This material has characteristics that make it an excellent alpha detector for tagging the time and direction of individual neutrons produced by t-d and d-d neutron generators (associated particle imaging). The intensity and decay time are strongly dependent on the method used for dopant incorporation. We compare samples made by diffusion of Ga metal to samples made by solid state reaction between ZnO and Ga2O3 followed by reduction in hydrogen. The latter is much more successful and has a pure, strong near-band-edge fluorescence and an ultra-fast decay time of the x-ray-excited luminescence. The luminescence increases dramatically as the temperature is reduced to 10K. We also present results of an alternate low-temperature synthesis that produces luminescent particles with a more uniform size distribution. We examine possible mechanisms for the bright near-band-edge scintillation and favor the explanation that it is due to the recombination of Ga3+ donor electrons with ionization holes trapped on H+ ion acceptors.

  6. Crystal orientation mechanism of ZnTe epilayers formed on different orientations of sapphire substrates by molecular beam epitaxy

    SciTech Connect (OSTI)

    Nakasu, T., E-mail: n-taizo.nakasu@asagi.waseda.jp; Yamashita, S.; Aiba, T.; Hattori, S.; Sun, W.; Taguri, K.; Kazami, F. [Department of Electrical Engineering and Bioscience, Waseda University, Tokyo 169-8555 (Japan); Kobayashi, M. [Department of Electrical Engineering and Bioscience, Waseda University, Tokyo 169-8555 (Japan); Kagami Memorial Research Institute for Materials and Technology, Waseda University, Tokyo 169-0051 (Japan)

    2014-10-28T23:59:59.000Z

    The electrooptic effect in ZnTe has recently attracted research attention, and various device structures using ZnTe have been explored. For application to practical terahertz wave detector devices based on ZnTe thin films, sapphire substrates are preferred because they enable the optical path alignment to be simplified. ZnTe/sapphire heterostructures were focused upon, and ZnTe epilayers were prepared on highly mismatched sapphire substrates by molecular beam epitaxy. Epitaxial relationships between the ZnTe thin films and the sapphire substrates with their various orientations were investigated using an X-ray diffraction pole figure method. (0001) c-plane, (1-102) r-plane, (1-100) m-plane, and (11-20) a-plane oriented sapphire substrates were used in this study. The epitaxial relationship between ZnTe and c-plane sapphire was found to be (111) ZnTe//(0001) sapphire with an in-plane orientation relationship of [?211] ZnTe//[1-100] sapphire. It was found that the (211)-plane ZnTe layer was grown on the m-plane of the sapphire substrates, and the (100)-plane ZnTe layer was grown on the r-plane sapphire. When the sapphire substrates were inclined from the c-plane towards the m-axis direction, the orientation of the ZnTe thin films was then tilted from the (111)-plane to the (211)-plane. The c-plane of the sapphire substrates governs the formation of the (111) ZnTe domain and the ZnTe epilayer orientation. These crystallographic features were also related to the atom arrangements of ZnTe and sapphire.

  7. Residual and nitrogen doping of homoepitaxial nonpolar m-plane ZnO films grown by molecular beam epitaxy

    SciTech Connect (OSTI)

    Taienoff, D.; Deparis, C.; Teisseire, M.; Morhain, C. [Centre de Recherche sur l'Hetero-Epitaxie et ses Applications, Centre National de la Recherche Scientifique (CRHEA-CNRS), Rue B. Gregory, F-06560 Valbonne Sophia Antipolis (France); Al-Khalfioui, M.; Vinter, B.; Chauveau, J.-M. [Centre de Recherche sur l'Hetero-Epitaxie et ses Applications, Centre National de la Recherche Scientifique (CRHEA-CNRS), Rue B. Gregory, F-06560 Valbonne Sophia Antipolis (France); Universite de Nice Sophia Antipolis, Parc Valrose F-06103 Nice (France)

    2011-03-28T23:59:59.000Z

    We report the homoepitaxial growth by molecular beam epitaxy of high quality nonpolar m-plane ZnO and ZnO:N films over a large temperature range. The nonintentionally doped ZnO layers exhibit a residual doping as low as {approx}10{sup 14} cm{sup -3}. Despite an effective incorporation of nitrogen, p-type doping was not achieved, ZnO:N films becoming insulating. The high purity of the layers and their low residual n-type doping evidence compensation mechanisms in ZnO:N films.

  8. In situ corrosion analysis of Al-Zn-In-Mg-Ti-Ce sacrificial anode alloy

    SciTech Connect (OSTI)

    Ma Jingling, E-mail: majingling.student@sina.com; Wen Jiuba; Zhai Wenxia; Li Quanan

    2012-03-15T23:59:59.000Z

    The corrosion behaviour of Al-5Zn-0.02In-1Mg-0.05Ti-0.5Ce (wt.%) alloy has been investigated by immersion test, scanning electron microscopy, energy dispersive X-ray detector, electrochemical impedance spectroscopy and electrochemical noise. The results show that there exist different corrosion types of the alloy in 3.5% NaCl solution with the immersion time. At the initial stage of immersion, pitting due to the precipitates predominates the corrosion with a typical inductive loop at low frequencies in electrochemical impedance spectroscopy. The major precipitates of the alloy are MgZn{sub 2} and Al{sub 2}CeZn{sub 2} particles. The corrosion potentials of the bulk MgZn{sub 2} and Al{sub 2}CeZn{sub 2} alloys are negative with respect to that of {alpha}-Al, so the MgZn{sub 2} and Al{sub 2}CeZn{sub 2} precipitates can act as activation centre and cause the pitting. In the late corrosion, a relative uniform corrosion predominates the corrosion process controlled by the dissolution/precipitation of the In ions and characterized by a capacitive loop at medium-high frequencies in electrochemical impedance spectroscopy. The potential noise of the pitting shows larger amplitude fluctuation and lower frequency, but the potential noise of the uniform corrosion occurs with smaller amplitude fluctuation and higher frequency.

  9. Ethanol Steam Reforming on Co/CeO2: The Effect of ZnO Promoter

    SciTech Connect (OSTI)

    Davidson, Stephen; Sun, Junming; Wang, Yong

    2013-12-02T23:59:59.000Z

    A series of ZnO promoted Co/CeO2 catalysts were synthesized and characterized using XRD, TEM, H2-TPR, CO chemisorption, O2-TPO, IR-Py, and CO2-TPD. The effects of ZnO on the catalytic performances of Co/CeO2 were studied in ethanol steam reforming. It was found that the addition of ZnO facilitated the oxidation of Co0 via enhanced oxygen mobility of the CeO2 support which decreased the activity of Co/CeO2 in CC bond cleavage of ethanol. 3 wt% ZnO promoted Co/CeO2 exhibited minimum CO and CH4 selectivity and maximum CO2 selectivity. This resulted from the combined effects of the following factors with increasing ZnO loading: (1) enhanced oxygen mobility of CeO2 facilitated the oxidation of CHx and CO to form CO2; (2) increased ZnO coverage on CeO2 surface reduced the interaction between CHx/CO and Co/CeO2; and (3) suppressed CO adsorption on Co0 reduced CO oxidation rate to form CO2. In addition, the addition of ZnO also modified the surface acidity and basicity of CeO2, which consequently affected the C2C4 product distributions.

  10. Physical properties of GdFe 2 (Al x Zn 1 ? x ) 20

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ni, N.; Jia, S.; Samolyuk, G. D.; Kracher, A.; Sefat, A. S.; Budko, S. L.; Canfield, P. C.

    2011-02-01T23:59:59.000Z

    The high ferromagnetic ordering temperature of the dilute, rare-earth-bearing, intermetallic compound GdFe?Zn?? has been understood as being the consequence of the Gd? moment being embedded in a nearly ferromagnetic Fermi liquid. To test this understanding in detail, single crystals of the pseudoternary series GdFe?(AlxZn1-x)?? (x?0.122) and YFe?(AlxZn1-x)?? (x?0.121) were grown out of Zn-rich solution. Magnetization, heat capacity, and resistivity measurements show that, with Al doping, the ferromagnetic phase transition temperatures of the GdFe?(AlxZn1-x)?? compounds decrease from 86 K (x= 0) to 10 K (x= 0.122); for the nonmagnetic analog, the YFe?(AlxZn1-x)?? series, the Stoner enhancement factor Z decreases from 0.88 (x= 0) to 0.35 (x= 0.121) in a similar manner. Tight-binding linear-muffin-tin orbital atomic-sphere approximation band structure calculations are used to rationalize this trend. These results, together with the earlier studies of the R(Fe1-xCox)?Zn?? (R= Gd and Y) series, clearly highlight the importance of band filling and the applicability of even a simple, rigid-band model to these compounds.

  11. Paramagnetism and antiferromagnetic interactions in single-phase Fe-implanted ZnO

    E-Print Network [OSTI]

    Pereira, Lino Miguel da Costa; Correia, Joo Guilherme; Van Bael, M J; Temst, Kristiaan; Vantomme, Andr; Arajo, Joo Pedro

    2013-01-01T23:59:59.000Z

    As the intrinsic origin of the high temperature ferromagnetism often observed in wide-gap dilute magnetic semiconductors becomes increasingly debated, there is a growing need for comprehensive studies on the single-phase region of the phase diagram of these materials. Here we report on the magnetic and structural properties of Fe-doped ZnO prepared by ion implantation of ZnO single crystals. A detailed structural characterization shows that the Fe impurities substitute for Zn in ZnO in a wurtzite Zn$_{1?x}$Fe$_{x}$O phase which is coherent with the ZnO host. In addition, the density of beam-induced defects is progressively decreased by thermal annealing up to 900$^ {?}$C, from highly disordered after implantation to highly crystalline upon subsequent annealing. Based on a detailed analysis of the magnetometry data, we demonstrate that isolated Fe impurities occupying Zn substitutional sites behave as localized paramagnetic moments down to 2 K, irrespective of the Fe concentration and the density of beam-i...

  12. Identification of As-vacancy complexes in Zn-diffused GaAs

    SciTech Connect (OSTI)

    Elsayed, M. [Department of Physics, Martin Luther University Halle, 06099 Halle (Germany); Department of Physics, Faculty of Science, Minia University, 61519 Minia (Egypt); Krause-Rehberg, R. [Department of Physics, Martin Luther University Halle, 06099 Halle (Germany); Korff, B. [Bremen Center for Computational Materials Science, University Bremen, 28359 Bremen (Germany); Richter, S. [Fraunhofer Center for Silicon Photovoltaics CSP, 06120 Halle (Saale) (Germany); Leipner, H. S. [Center of Materials Science, Martin Luther University Halle, 06099 Halle (Germany)

    2013-03-07T23:59:59.000Z

    We have used positron annihilation spectroscopy to study the introduction of point defects in Zn-diffused semi-insulating GaAs. The diffusion was performed by annealing the samples for 2 h at 950 Degree-Sign C. The samples were etched in steps of 7 {mu}m. Both Doppler broadening using slow positron beam and lifetime spectroscopy studies were performed after each etching step. Both techniques showed the existence of vacancy-type defects in a layer of about 45 {mu}m. Secondary ion mass spectroscopy measurements illustrated the presence of Zn at high level in the sample almost up to the same depth. Vacancy-like defects as well as shallow positron traps were observed by lifetime measurements. We distinguish two kinds of defects: As vacancy belongs to defect complex, bound to most likely one Zn atom incorporated on Ga sublattice, and negative-ion-type positron traps. Zn acceptors explained the observation of shallow traps. The effect of Zn was evidenced by probing GaAs samples annealed under similar conditions but without Zn treatment. A defect-free bulk lifetime value is detected in this sample. Moreover, our positron annihilation spectroscopy measurements demonstrate that Zn diffusion in GaAs system is governed by kick-out mechanism.

  13. ZnO nanorod growth by plasma-enhanced vapor phase transport with different growth durations

    SciTech Connect (OSTI)

    Kim, Chang-Yong; Oh, Hee-bong [Department of Nano Science and Engineering, Inje University, Obang-dong, Gimhae, Gyeongnam 621-749 (Korea, Republic of); Ryu, Hyukhyun, E-mail: hhryu@inje.ac.kr [Department of Nano Science and Engineering, Center for Nano Manufacturing, Inje University, Obang-dong, Gimhae, Gyeongnam 621-749 (Korea, Republic of); Yun, Jondo [Department of Nano Science and Engineering, Kyungnam University, Changwon, Gyeongnam 631-701 (Korea, Republic of); Lee, Won-Jae [Department of Materials and Components Engineering, Dong-Eui University, 995 Eomgwangno, Busanjin-gu, Busan 614-714 (Korea, Republic of)

    2014-09-01T23:59:59.000Z

    In this study, the structural properties of ZnO nanostructures grown by plasma-enhanced vapor phase transport (PEVPT) were investigated. Plasma-treated oxygen gas was used as the oxygen source for the ZnO growth. The structural properties of ZnO nanostructures grown for different durations were measured by scanning electron microscopy, x-ray diffraction, and transmission electron microscopy. The authors comprehensively analyzed the growth of the ZnO nanostructures with different growth durations both with and without the use of plasma-treated oxygen gas. It was found that PEVPT has a significant influence on the growth of the ZnO nanorods. PEVPT with plasma-treated oxygen gas facilitated the generation of nucleation sites, and the resulting ZnO nanorod structures were more vertical than those prepared by conventional VPT without plasma-treated oxygen gas. As a result, the ZnO nanostructures grown using PEVPT showed improved structural properties compared to those prepared by the conventional VPT method.

  14. Low temperature atomic layer deposited ZnO photo thin film transistors

    SciTech Connect (OSTI)

    Oruc, Feyza B.; Aygun, Levent E.; Donmez, Inci; Biyikli, Necmi; Okyay, Ali K., E-mail: aokyay@ee.bilkent.edu.tr [Institute of Materials Science and Nanotechnology, Bilkent University, Bilkent, 06800 Ankara (Turkey); UNAMNational Nanotechnology Research Center, Bilkent University, Bilkent, 06800 Ankara (Turkey); Department of Electrical and Electronics Engineering, Bilkent University, Bilkent, 06800 Ankara (Turkey); Yu, Hyun Yong [The School of Electrical Engineering, Korea University, Seoul 136-701 (Korea, Republic of)

    2015-01-01T23:59:59.000Z

    ZnO thin film transistors (TFTs) are fabricated on Si substrates using atomic layer deposition technique. The growth temperature of ZnO channel layers are selected as 80, 100, 120, 130, and 250?C. Material characteristics of ZnO films are examined using x-ray photoelectron spectroscopy and x-ray diffraction methods. Stoichiometry analyses showed that the amount of both oxygen vacancies and interstitial zinc decrease with decreasing growth temperature. Electrical characteristics improve with decreasing growth temperature. Best results are obtained with ZnO channels deposited at 80?C; I{sub on}/I{sub off} ratio is extracted as 7.8 10{sup 9} and subthreshold slope is extracted as 0.116 V/dec. Flexible ZnO TFT devices are also fabricated using films grown at 80?C. I{sub D}V{sub GS} characterization results showed that devices fabricated on different substrates (Si and polyethylene terephthalate) show similar electrical characteristics. Sub-bandgap photo sensing properties of ZnO based TFTs are investigated; it is shown that visible light absorption of ZnO based TFTs can be actively controlled by external gate bias.

  15. Subbarrier fusion of {sup 9}Li with {sup 70}Zn

    SciTech Connect (OSTI)

    Loveland, W.; Vinodkumar, A. M.; Naik, R. S.; Sprunger, P. H.; Matteson, B.; Neeway, J. [Department of Chemistry, Oregon State University, Corvallis, Oregon 97331 (United States); Trinczek, M.; Dombsky, M.; Machule, P.; Ottewell, D. [TRIUMF, Vancouver, British Columbia, V6T 2A3 (Canada); Cross, D. [TRIUMF, Vancouver, British Columbia, V6T 2A3 (Canada); Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, V5A 1S6 (Canada); Gagnon, K.; Mills, W. J. [TRIUMF, Vancouver, British Columbia, V6T 2A3 (Canada); Department of Physics, Simon Fraser University, Burnaby, British Columbia, V5A 1S6 (Canada)

    2006-12-15T23:59:59.000Z

    The cross section for the fusion of {sup 9}Li with {sup 70}Zn was measured for seven projectile energies spanning the subbarrier and near-barrier region (E{sub c.m.} ranging from 9.7 to 13.4 MeV) using the ISAC facility at TRIUMF. {gamma}-ray spectroscopy of the irradiated target foils along with {beta} counting of the chemically separated Ge and As evaporation residues were used to measure the fusion cross sections. Statistical model calculations were used to correct for the yields of any unobserved nuclei. The observed fusion excitation function shows significant subbarrier fusion enhancement with a large deduced value of the fusion radius, R{sub B}=12.1{+-}1.0 fm. Coupled-channels calculations do not account for the observed subbarrier enhancement. The implications of this finding for understanding the fusion of {sup 11}Li are discussed.

  16. Development of Prototype Pixellated PIN CdZnTe Detectors

    E-Print Network [OSTI]

    T. Narita; P. Bloser; J. Grindlay; R. Sudharsanan; C. Reiche; C. Stenstrom

    1998-06-12T23:59:59.000Z

    We report initial results from the design and evaluation of two pixellated PIN Cadmium Zinc Telluride detectors and an ASIC-based readout system. The prototype imaging PIN detectors consist of 4X4 1.5 mm square indium anode contacts with 0.2 mm spacing and a solid cathode plane on 10X10 mm CdZnTe substrates of thickness 2 mm and 5 mm. The detector readout system, based on low noise preamplifier ASICs, allows for parallel readout of all channels upon cathode trigger. This prototype is under development for use in future astrophysical hard X-ray imagers with 10-600 keV energy response. Measurements of the detector uniformity, spatial resolution, and spectral resolution will be discussed and compared with a similar pixellated MSM detector. Finally, a prototype design for a large imaging array is outlined.

  17. ZnO/porous-Si and TiO{sub 2}/porous-Si nanocomposite nanopillars

    SciTech Connect (OSTI)

    Wang, Dong, E-mail: dong.wang@tu-ilmenau.de; Yan, Yong; Schaaf, Peter [Chair Materials for Electronics, Institute of Materials Engineering and Institute of Micro- and Nanotechnologies MacroNano, TU Ilmenau, Gustav-Kirchhoff-Str. 5, 98693 Ilmenau (Germany); Sharp, Thomas [Oxford Instruments Plasma Technology Ltd., Yatton, Bristol BS49 4AP (United Kingdom); Schnherr, Sven; Ronning, Carsten [Institute for Solid State Physics, Friedrich Schiller University Jena, Max-Wien-Platz 1, 07743 Jena (Germany); Ji, Ran [SUSS MicroTec Lithography GmbH, Schleissheimer Str. 90, 85748 Garching (Germany)

    2015-01-01T23:59:59.000Z

    Porous Si nanopillar arrays are used as templates for atomic layer deposition of ZnO and TiO{sub 2}, and thus, ZnO/porous-Si and TiO{sub 2}/porous-Si nanocomposite nanopillars are fabricated. The diffusion of the precursor molecules into the inside of the porous structure occurs via Knudsen diffusion and is strongly limited by the small pore size. The luminescence of the ZnO/porous-Si nanocomposite nanopillars is also investigated, and the optical emission can be changed and even quenched after a strong plasma treatment. Such nanocomposite nanopillars are interesting for photocatalysis and sensors.

  18. Inverse spin Hall effect induced by spin pumping into semiconducting ZnO

    SciTech Connect (OSTI)

    Lee, Jung-Chuan [Institute of Physics, Academia Sinica, Taipei 11529, Taiwan (China); Huang, Leng-Wei [Graduate Institute of Applied Physics, National Chengchi University, Taipei 11605, Taiwan (China); Hung, Dung-Shing, E-mail: dshung@mail.mcu.edu.tw [Institute of Physics, Academia Sinica, Taipei 11529, Taiwan (China); Department of Information and Telecommunications Engineering, Ming Chuan University, Taipei 111, Taiwan (China); Chiang, Tung-Han [Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China); Huang, J. C. A., E-mail: jcahuang@mail.ncku.edu.tw [Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China); Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 70101, Taiwan (China); Liang, Jun-Zhi [Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 70101, Taiwan (China); Department of Physics, Fu Jen Catholic University, Taipei 242, Taiwan (China); Lee, Shang-Fan, E-mail: leesf@phys.sinica.edu.tw [Institute of Physics, Academia Sinica, Taipei 11529, Taiwan (China); Graduate Institute of Applied Physics, National Chengchi University, Taipei 11605, Taiwan (China)

    2014-02-03T23:59:59.000Z

    The inverse spin Hall effect (ISHE) of n-type semiconductor ZnO thin films with weak spin-orbit coupling has been observed by utilizing the spin pumping method. In the ferromagnetic resonance condition, the spin pumping driven by the dynamical exchange interaction of a permalloy film injects a pure spin current into the adjacent ZnO layer. This spin current gives rise to a DC voltage through the ISHE in the ZnO layer, and the DC voltage is proportional to the microwave excitation power. The effect is sizeable even when the spin backflow is considered.

  19. Phosphorescence quenching by mechanical stimulus in CaZnOS:Cu

    SciTech Connect (OSTI)

    Tu, Dong; Kamimura, Sunao [National Institute of Advanced Industrial Science and Technology (AIST), Saga 841-0052 (Japan); Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Fukuoka 816-8580 (Japan); Xu, Chao-Nan, E-mail: cn-xu@aist.go.jp [National Institute of Advanced Industrial Science and Technology (AIST), Saga 841-0052 (Japan); Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Fukuoka 816-8580 (Japan); International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, Fukuoka 819-0395 (Japan); Fujio, Yuki; Sakata, Yoshitaro [National Institute of Advanced Industrial Science and Technology (AIST), Saga 841-0052 (Japan); Ueno, Naohiro [National Institute of Advanced Industrial Science and Technology (AIST), Saga 841-0052 (Japan); Graduate School of Science and Engineering, Saga University, Saga 840-8502 (Japan)

    2014-07-07T23:59:59.000Z

    We have found that phosphorescence intensity of CaZnOS:Cu decreased visibly under an applied load. This mechanical quenching (MQ) of phosphorescence in CaZnOS:Cu corresponded to the mechanical stimuli. We have thus demonstrated that the MQ of CaZnOS:Cu could be used for visualizing stress distributions in practical applications. We propose that MQ arises from non-radiative recombination due to electron-transfer from trap levels to non-radiative centers as a result of the mechanical load.

  20. Measurements of sputtered neutrals and ions and investigation of their roles on the plasma properties during rf magnetron sputtering of Zn and ZnO targets

    SciTech Connect (OSTI)

    Maaloul, L.; Stafford, L. [Dpartement de Physique, Universit de Montral, Montral, Qubec H3C 3J7 (Canada)] [Dpartement de Physique, Universit de Montral, Montral, Qubec H3C 3J7 (Canada)

    2013-11-15T23:59:59.000Z

    Langmuir probe and optical absorption spectroscopy measurements were used to determine the line-integrated electron density, electron temperature, and number density of Ar atoms in metastable {sup 3}P{sub 2} and {sup 3}P{sub 0} levels in a 5 mTorr, rf magnetron sputtering plasmas used for the deposition of ZnO-based thin films. While the average electron energy and density of Ar atoms in {sup 3}P{sub 2} and {sup 3}P{sub 0} excited states were fairly independent of self-bias voltage, the Ar {sup 3}P{sub 2}-to-electron number density ratio decreased by approximately a factor of 5 when going from ?115 V to ?300 V. This decrease was correlated to an increase by about one order of magnitude of the number density of sputtered Zn atoms determined by absolute actinometry measurements on Zn I using either Ar or Xe as the actinometer gas. These results were also found to be in excellent agreement with the predictions of a global model accounting for Penning ionization of sputtered Zn particles. The importance of the latter reactions was further confirmed by plasma sampling mass spectrometry showing a double peak structure for Zn ions: a low-energy component ascribed to thermalized ions created in the gas phase (by direct electron impact and by Penning ionization) and a high-energy tail due to ions ejected from the target and reaching quasi-collisionlessly the substrate surface.

  1. Thermal conductivity of self-assembled nano-structured ZnO bulk ceramics

    SciTech Connect (OSTI)

    Zhao, Yu [Bio-Inspired Materials and Devices Laboraory (BMDL); Yan, Yongke [Bio-Inspired Materials and Devices Laboraory (BMDL); Kumar, Ashok [Bio-Inspired Materials and Devices Laboraory (BMDL); Wang, Hsin [ORNL; Porter, Wallace D [ORNL

    2012-01-01T23:59:59.000Z

    In this study, we describe the changes in thermal conductivity behavior of ZnO-Al micro- and nano-two-phase self-assembled composites with varying grain sizes. The reduction in thermal conductivity values of micro-composites was limited to {approx}15% for ZnO-4% Al. However, nano-composites exhibited large reduction, by a factor of about three, due to uniform distribution of nano-precipitates (ZnAl2O4) and large grain boundary area. Interestingly, the micro-composites revealed continuous decrease in thermal conductivity with increase in Al substitution while the nano-composites exhibited the lowest magnitudes for 2% Al concentration. Raman spectra indicated that phonon confinement in ZnO-Al nano-composites causes drastic decrease in the value of thermal conductivity.

  2. Optimizing the Power Output of a ZnO Photocell by Piezopotential

    E-Print Network [OSTI]

    Wang, Zhong L.

    properties of ZnO make it an ideal choice for applications in nanogenerators10 13 for converting mechanical together with the thermionic emission theory has explained the four kinds of relationships observed

  3. Fabrication and Luminescence of ZnS:Mn2+ Nanoflowers. | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of ZnS:Mn2+ nanoparticles are prepared and characterized. The configurations of these fractal structures are very sensitive to both the pH values of the particle solutions from...

  4. The effect of PdZn particle size on reverse-water-gas-shift reaction...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    RWGS activity is consistent with that previously observed for the steam reforming of methanol, i.e., higher CO selectivity on smaller PdZn particles. Thus, RWGS has been...

  5. Synthesis and Luminescence of ZnMgS:Mn2+ Nanoparticles. | EMSL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    followed by a post-annealing process, thus showing the features of less complexity, low cost, and easy incorporation of dopants. In comparison with the emission of ZnS:Mn2+...

  6. Development of ZnO Based Light Emitting Diodes and Laser Diodes

    E-Print Network [OSTI]

    Kong, Jieying

    2012-01-01T23:59:59.000Z

    E. Fred Schubert, Light-Emitting Diodes, New York (2006) [8]ZnO homojunction light emitting diode 3. 1. Motivation ofAlGaAs red light-emitting diodes, in: G.B. Stringfellow, M.

  7. Synthesis of ZnO decorated graphene nanocomposite for enhanced photocatalytic properties

    SciTech Connect (OSTI)

    Gayathri, S.; Jayabal, P. [Department of Laser Studies, School of Physics, Madurai Kamaraj University, Madurai 625021, Tamilnadu (India); Kottaisamy, M. [Department of Chemistry, Thiagarajar College of Engineering, Madurai 625014, Tamilnadu (India); Ramakrishnan, V., E-mail: vr.optics1@gmail.com [Department of Laser Studies, School of Physics, Madurai Kamaraj University, Madurai 625021, Tamilnadu (India); Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram 695016, Kerala (India)

    2014-05-07T23:59:59.000Z

    Zinc oxide/Graphene (GZ) composites with different concentrations of ZnO were successfully synthesized through simple chemical precipitation method. The X-ray diffraction pattern and the micro-Raman spectroscopic technique revealed the formation of GZ composite, and the energy dispersive X-ray spectrometry analysis showed the purity of the prepared samples. The ZnO nanoparticles decorated graphene sheets were clearly visible in the field emission scanning electron micrograph. Raman mapping was employed to analyze the homogeneity of the prepared samples. The diffuse-reflectance spectra clearly indicated that the formation of GZ composites promoted the absorption in the visible region also. The photocatalytic activity of ZnO and GZ composites was studied by the photodegradation of Methylene blue dye. The results revealed that the GZ composites exhibited a higher photocatalytic activity than pristine ZnO. Hence, we proposed a simple wet chemical method to synthesize GZ composite and its application on photocatalysis was demonstrated.

  8. ZnO PN Junctions for Highly-Efficient, Low-Cost Light Emitting Diodes

    SciTech Connect (OSTI)

    David P. Norton; Stephen Pearton; Fan Ren

    2007-09-30T23:59:59.000Z

    By 2015, the US Department of Energy has set as a goal the development of advanced solid state lighting technologies that are more energy efficient, longer lasting, and more cost-effective than current technology. One approach that is most attractive is to utilize light-emitting diode technologies. Although III-V compound semiconductors have been the primary focus in pursuing this objective, ZnO-based materials present some distinct advantages that could yield success in meeting this objective. As with the nitrides, ZnO is a direct bandgap semiconductor whose gap energy (3.2 eV) can be tuned from 3.0 to 4 eV with substitution of Mg for higher bandgap, Cd for lower bandgap. ZnO has an exciton binding energy of 60 meV, which is larger than that for the nitrides, indicating that it should be a superior light emitting semiconductor. Furthermore, ZnO thin films can be deposited at temperatures on the order of 400-600 C, which is significantly lower than that for the nitrides and should lead to lower manufacturing costs. It has also been demonstrated that functional ZnO electronic devices can be fabricated on inexpensive substrates, such as glass. Therefore, for the large-area photonic application of solid state lighting, ZnO holds unique potential. A significant impediment to exploiting ZnO in light-emitting applications has been the absence of effective p-type carrier doping. However, the recent realization of acceptor-doped ZnO material overcomes this impediment, opening the door to ZnO light emitting diode development In this project, the synthesis and properties of ZnO-based pn junctions for light emitting diodes was investigated. The focus was on three issues most pertinent to realizing a ZnO-based solid state lighting technology, namely (1) achieving high p-type carrier concentrations in epitaxial and polycrystalline films, (2) realizing band edge emission from pn homojunctions, and (3) investigating pn heterojunction constructs that should yield efficient light emission. The project engaged established expertise at the University of Florida in ZnO film growth (D. Norton), device fabrication (F. Ren) and wide bandgap photonics (S. Pearton). It addressed p-type doping and junction formation in (Zn,Mg)O alloy thin films. The project employed pulsed laser deposition for film growth. The p-type dopant of interest was primarily phosphorus, given the recent results in our laboratory and elsewhere that this anions can yield p-type ZnO-based materials. The role of Zn interstitials, oxygen vacancies, and/or hydrogen complexes in forming compensating shallow donor levels imposes the need to simultaneously consider the role of in situ and post-growth processing conditions. Temperature-dependent Hall, Seebeck, C-V, and resistivity measurements was used to determine conduction mechanisms, carrier type, and doping. Temperature-dependent photoluminescence was used to determine the location of the acceptor level, injection efficiency, and optical properties of the structures. X-ray diffraction will used to characterize film crystallinity. Using these materials, the fabrication and characterization of (Zn,Mg)O pn homojunction and heterojunction devices was pursued. Electrical characterization of the junction capacitance and I-V behavior was used to extract junction profile and minority carrier lifetime. Electroluminescence from biased junctions was the primary property of interest.

  9. Electrodeposition of ZnO Nanorods in the Presence of Metal Ions...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    B Wutzke, and RF Koenenkamp.2009."Electrodeposition of ZnO Nanorods in the Presence of Metal Ions."Materials Letters 63(9-10):736-738. doi:10.1016j.matlet.2008.12.037 Authors:...

  10. Soil and Mold Influences on Fe and Zn Concentrations of Sorghum Grain in Mali, West Africa

    E-Print Network [OSTI]

    Verbree, Cheryl

    2012-10-19T23:59:59.000Z

    Iron (Fe) and zinc (Zn) deficiencies affect an estimated 3 billion people worldwide and are linked with cognitive and physical impairments, maternal and child mortality rates, and decreased adult work activity. To combat this "hidden" hunger, plant...

  11. The Effect of Zn Addition on the Oxidation State of Cobalt in...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    effect of Zn promotion on the activity and selectivity of CoZrO2 catalysts for ethanol steam reforming was investigated. The catalysts were synthesized by incipient wetness...

  12. Inhibition Mechanisms of Zn Precipitation on Aluminum Oxide by Glyphosate: A 31

    E-Print Network [OSTI]

    Sparks, Donald L.

    and crops, and becomes a potential threat to human beings via the food chain.5 In soils, excessive Zn can, and an -Ni hydroxide formed instead due to the complexation of Al by these two organic ligands. Likewise

  13. Spinel ferrite nanocrystals embedded inside ZnO: magnetic, electronic and magneto-transport properties

    E-Print Network [OSTI]

    Zhou, Shengqiang

    2010-01-01T23:59:59.000Z

    Spinel ferrite nanocrystals embedded inside ZnO: magnetic,paper we show that spinel ferrite nanocrystals (NiFe 2 O 4 ,annealing. The two kinds of ferrites show di?erent magnetic

  14. Polymeric precursor derived nanocrystalline ZnO thin films using EDTA as chelating agent

    E-Print Network [OSTI]

    Mohanty, Saraju P.

    properties, ZnO has plausible electro-optical applications, such as, solar cells [1, 2], light- emitting diodes [3, 4], UV lasers [5], thin film transistors [6,7], and UV photodetectors [8]. Besides

  15. Colloidal Nanocrystals of Wurtzite Zn1-xCoxO (0 ? x ? 1)...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Zn1-xCoxO (0 ? x ? 1): Models of Spinodal Decomposition in an Oxide Diluted Magnetic Semiconductor."Chemistry of Materials 20(22):7107-7116. doi:10.1021cm802280g Authors: MA...

  16. A New Cell-Permeable Fluorescent Probe for Zn2+ Grant K. Walkup,

    E-Print Network [OSTI]

    Tsien, Roger Y.

    of Chemistry Massachusetts Institute of Technology Cambridge, Massachusetts, 02139 ReceiVed March 10, 2000 Re gene expression,3 apoptosis,4 enzyme regulation,5 and neurotransmission6,7 suggests that Zn2+ may

  17. Zn Speciation in the Organic Horizon of a Contaminated Soil by

    E-Print Network [OSTI]

    . Such an organic topsoil, located downwind of an active zinc smelter and extremely rich in Zn (2%, dry weight the transfer of metals to the drinking water and to the food chain. The zinc smelter of Auby (Nord, France) has

  18. Terahertz Dielectric Properties and Low-Frequency Phonon Resonances of ZnO Nanostructures

    E-Print Network [OSTI]

    spectral region, and therefore it can be used as the transparent conductive electrodes in solar cells and flat panel displays.10 Additionally, surface acoustic wave filters made from ZnO films have been used

  19. Residue Ionization in LpxC Directly Observed by 67Zn NMR Spectroscopy...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Abstract: The pH dependence of the 67Zn NMR spectroscopy has been measured for both wild type (WT) and the H265A mutant of LpxC, each in the resting state absence of...

  20. Electronic Structure of ZnO:GaN Compounds: Asymmetric Bandgap Engineering

    SciTech Connect (OSTI)

    Huda, M. N.; Yan, Y.; Wei, S. H.; Al-Jassim, M. M.

    2008-11-01T23:59:59.000Z

    ZnO and GaN have a type-II band offset. The incorporation of one compound into the other would lead to a reduced bandgap as compared to that of either ZnO or GaN. Our density-functional theory calculation reveals an asymmetric bandgap reduction in this nonisovalent system; i.e., incorporating GaN in a ZnO host results in a much more effective bandgap reduction than incorporating ZnO in a GaN host. We further find that the random-alloy system is more favorable than the superlattice system in terms of light absorption in the longer-wavelength regions. Our results suggest that the wave-function localization at the band edges plays an important role in how to choose the host material and dopant for effective bandgap engineering through semiconductor compound alloying.

  1. Ferromagnetism in Ti-Doped ZnO Nanoclusters above Room Temperature...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    increase of temperature. Citation: Antony J, S Pendyala, DE McCready, MH Engelhard, D Meyer, AM Sharma, and Y Qiang.2006."Ferromagnetism in Ti-Doped ZnO Nanoclusters above Room...

  2. ZnO nanowires on glass via chemical routes: A prospective photocatalyst for indoors applications

    E-Print Network [OSTI]

    O:Al Seed layer Photocatalysis Stearic acid A B S T R A C T Versatile ZnO nanowires with controlled applications. 2014 Elsevier Ltd. All rights reserved. Introduction Heterogeneous photocatalysis is attracting

  3. Multianalyte biosensor based on pH-sensitive ZnO electrolyteinsulatorsemiconductor structures

    SciTech Connect (OSTI)

    Haur Kao, Chyuan; Chun Liu, Che; Ueng, Herng-Yih [Department of Electronic Engineering, Chang Gung University, Kwei-Shan, Tao-Yuan 333, Taiwan (China); Chen, Hsiang, E-mail: hchen@ncnu.edu.tw; Cheng Chu, Yu; Jie Chen, Yu [Department of Applied Materials and Optoelectronic Engineering, National Chi Nan University, Puli, Nantou 545, Taiwan (China); Ling Lee, Ming; Ming Chang, Kow [Department of Electronic Engineering, National Chiao Tung University, Hsin-Chu 300, Taiwan (China)

    2014-05-14T23:59:59.000Z

    Multianalyte electrolyteinsulatorsemiconductor (EIS) sensors with a ZnO sensing membrane annealed on silicon substrate for use in pH sensing were fabricated. Material analyses were conducted using X-ray diffraction and atomic force microscopy to identify optimal treatment conditions. Sensing performance for various ions of Na{sup +}, K{sup +}, urea, and glucose was also tested. Results indicate that an EIS sensor with a ZnO membrane annealed at 600?C exhibited good performance with high sensitivity and a low drift rate compared with all other reported ZnO-based pH sensors. Furthermore, based on well-established pH sensing properties, pH-ion-sensitive field-effect transistor sensors have also been developed for use in detecting urea and glucose ions. ZnO-based EIS sensors show promise for future industrial biosensing applications.

  4. Single-valley quantum Hall ferromagnet in a dilute MgxZn1-xO/ZnO strongly correlated two-dimensional electron system

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kozuka, Y.; Tsukazaki, A.; Maryenko, D.; Falson, J.; Bell, C.; Kim, M.; Hikita, Y.; Hwang, H. Y.; Kawasaki, M.

    2012-02-01T23:59:59.000Z

    We investigate the spin susceptibility (g*m*) of dilute two-dimensional (2D) electrons confined at the MgxZn1-xO/ZnO heterointerface. Magnetotransport measurements show a four-fold enhancement of g*m*, dominated by the increase in the Land g-factor. The g-factor enhancement leads to a ferromagnetic instability of the electron gas as evidenced by sharp resistance spikes. At high magnetic field, the large g*m* leads to full spin polarization, where we found sudden increase in resistance around the filling factors of half-integer, accompanied by complete disappearance of fractional quantum Hall (QH) states. Along with its large effective mass and the high electron mobility, our result indicates that the ZnO 2D system is ideal for investigating the effect of electron correlations in the QH regime.

  5. Single-valley quantum Hall ferromagnet in a dilute MgxZn1-xO/ZnO strongly correlated two-dimensional electron system

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kozuka, Y.; Tsukazaki, A.; Maryenko, D.; Falson, J.; Bell, C.; Kim, M.; Hikita, Y.; Hwang, H. Y.; Kawasaki, M.

    2012-02-01T23:59:59.000Z

    We investigate the spin susceptibility (g*m*) of dilute two-dimensional (2D) electrons confined at the MgxZn1-xO/ZnO heterointerface. Magnetotransport measurements show a four-fold enhancement of g*m*, dominated by the increase in the Land g-factor. The g-factor enhancement leads to a ferromagnetic instability of the electron gas as evidenced by sharp resistance spikes. At high magnetic field, the large g*m* leads to full spin polarization, where we found sudden increase in resistance around the filling factors of half-integer, accompanied by complete disappearance of fractional quantum Hall (QH) states. Along with its large effective mass and the high electron mobility, our result indicates thatmorethe ZnO 2D system is ideal for investigating the effect of electron correlations in the QH regime.less

  6. Synthesis of highly efficient antibacterial agent Ag doped ZnO nanorods: Structural, Raman and optical properties

    SciTech Connect (OSTI)

    Jan, Tariq; Iqbal, Javed, E-mail: javed.saggu@iiu.edu.pk [Laboratory of Nanoscience and Technology, Department of Physics, International Islamic University Islamabad (Pakistan); Ismail, Muhammad [Institute of Biomedical and Genetic Engineering (IBGE), Islamabad (Pakistan); Mahmood, Arshad [Nano Devices Labs, National Institute of Lasers and Optronics, Islamabad (Pakistan)

    2014-04-21T23:59:59.000Z

    Here, synthesis, structural, morphological, Raman, optical properties and antibacterial activity of undoped and Ag doped ZnO nanorods by chemical co-precipitation technique have been reported. Structural analysis has revealed that Ag doping cannot deteriorate the structure of ZnO and wurtzite phase is maintained. Lattice constants are found to be decreased with the Ag doping. Fourier transform infrared and Raman spectroscopy also confirm the X-ray diffraction results. Scanning electron microscopy results have demonstrated the formation of ZnO nanorods with average diameter and length of 96?nm and 700?nm, respectively. Raman spectroscopy results suggest that the Ag doping enhances the number of defects in ZnO crystal. It has been found from optical study that Ag doping results in positional shift of band edge absorption peak. This is attributed to the successful incorporation of Ag dopant into ZnO host matrix. The antibacterial activity of prepared nanorods has been determined by two different methods and compared to that of undoped ZnO nanorods. Ag doped ZnO nanorods exhibit excellent antibacterial activity as compared to that of undoped ZnO nanorods. This excellent antibacterial activity may be attributed to the presence of oxygen vacancies and Zn{sup 2+} interstitial defects. Our preliminary findings suggest that Ag doped ZnO nanorods can be used externally to control the spreading of infections related with tested bacterial strains.

  7. Thin-film polycrystalline n-ZnO/p-CuO heterojunction

    SciTech Connect (OSTI)

    Lisitski, O. L.; Kumekov, M. E.; Kumekov, S. E. [Satpaev Kazakh National Technical University (Kazakhstan)], E-mail: skumekov@mail.ru; Terukov, E. I. [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation)

    2009-06-15T23:59:59.000Z

    Results of X-ray diffraction and spectral-optical studies of n-ZnO and p-CuO films deposited by gas-discharge sputtering with subsequent annealing are presented. It is shown that, despite the difference in the crystal systems, the polycrystallinity of n-ZnO and p-CuO films enables fabrication of a heterojunction from this pair of materials.

  8. Low-temperature aqueous-phase reforming of ethanol on bimetallic PdZn catalysts

    SciTech Connect (OSTI)

    Xiong, Haifeng; DelaRiva, Andrew; Wang, Yong; Dayte, Abhaya

    2015-01-01T23:59:59.000Z

    Bimetallic PdZn catalysts supported on carbon black (CB) and carbon nanotubes (CNTs) were found to be selective for CO-free H-2 production from ethanol at low temperature (250 degrees C). On Pd, the H-2 yield was low (similar to 0.3 mol H-2/mol ethanol reacted) and the CH4/CO2 ratio was high (similar to 1.7). Addition of Zn to Pd formed the intermetallic PdZn beta phase (atomic ratio of Zn to Pd is 1) with increased H-2 yield (similar to 1.9 mol H-2/mol ethanol reacted) and CH4/CO2 ratio of <1. The higher H-2 yield and low CH4 formation was related to the improved dehydrogenation activity of the L1(0) PdZn beta phase. The TOF increased with particle size and the CNTs provided the most active and selective catalysts, which may be ascribed to pore-confinement effects. Furthermore, no significant changes in either the supports or the PdZn beta particles was found after aqueous-phase reforming (APR) indicating that the metal nanoparticles and the carbon support are hydrothermally stable in the aqueous phase at elevated temperatures and pressures (>200 degrees C, 65 bar). No CO was detected for all the catalysts performed in aqueous-phase reaction, indicating that both monometallic Pd and bimetallic PdZn catalysts have high water-gas shift activity during APR. However, the yield of H-2 is considerably lower than the theoretical value of 6 H-2 per mole ethanol which is due to the presence of oxygenated products and methane on the PdZn catalysts.

  9. Self-assembled ultra small ZnO nanocrystals for dye-sensitized solar cell application

    SciTech Connect (OSTI)

    Patra, Astam K.; Dutta, Arghya; Bhaumik, Asim, E-mail: msab@iacs.res.in

    2014-07-01T23:59:59.000Z

    We demonstrate a facile chemical approach to produce self-assembled ultra-small mesoporous zinc oxide nanocrystals using sodium salicylate (SS) as a template under hydrothermal conditions. These ZnO nanomaterials have been successfully fabricated as a photoanode for the dye-sensitized solar cell (DSSC) in the presence of N719 dye and iodinetriiodide electrolyte. The structural features, crystallinity, purity, mesophase and morphology of the nanostructure ZnO are investigated by several characterization tools. N{sub 2} sorption analysis revealed high surface areas (203 m{sup 2} g{sup ?1}) and narrow pore size distributions (5.15.4 nm) for different samples. The mesoporous structure and strong photoluminescence facilitates the high dye loading at the mesoscopic void spaces and light harvesting in DSSC. By utilizing this ultra-small ZnO photoelectrode with film thickness of about 7 ?m in the DSSC with an open-circuit voltage (V{sub OC}) of 0.74 V, short-circuit current density (J{sub SC}) of 3.83 mA cm{sup ?2} and an overall power conversion efficiency of 1.12% has been achieved. - Graphical abstract: Ultra-small ZnO nanocrystals have been synthesized with sodium salicylate as a template and using it as a photoanode in a dye-sensitized solar cell 1.12% power conversion efficiency has been observed. - Highlights: Synthesis of self-assembled ultra-small mesoporous ZnO nanocrystals by using sodium salicylate as a template. Mesoporous ZnO materials have high BET surface areas and void space. ZnO nanoparticles serve as a photoanode for the dye-sensitized solar cell (DSSC). Using ZnO nanocrystals as photoelectrode power conversion efficiency of 1.12% has been achieved.

  10. Waferscale highthroughput ordered growth of vertically aligned ZnO nanowire arrays

    E-Print Network [OSTI]

    Wang, Zhong L.

    arrays on GaN substrate with different periods and sizes 2 m 3 m Figure S1. LIL-Patterned growth of ZnO NW arrays on GaN substrate with different periods and sizes of opened-holes. (a) and (b) Top-view and 45o side-view SEM images of vertically aligned ZnO NW arrays on GaN substrate with 200 nm opened

  11. Mechanical and transparent conductive properties of ZnO and Ga-doped ZnO films sputtered using electron-cyclotron-resonance plasma on polyethylene naphtalate substrates

    SciTech Connect (OSTI)

    Akazawa, Housei, E-mail: akazawa.housei@lab.ntt.co.jp [NTT Microsystem Integration Laboratories 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198 (Japan)

    2014-03-15T23:59:59.000Z

    Transparent conductive ZnO and Ga-doped ZnO (GZO) films were deposited on polyethylene naphtalate (PEN) sheet substrates using electron cyclotron resonance plasma sputtering. Both ZnO and GZO films were highly adhesive to the PEN substrates without inserting an intermediate layer in the interface. When compared at the same thickness, the transparent conductive properties of GZO films on PEN substrates were only slightly inferior to those on glass substrates. However, the carrier concentration of ZnO films on PEN substrates was 1.5?times that of those on glass substrates, whereas their Hall mobility was only 60% at a thickness of 300?nm. The depth profile of elements measured by secondary ion mass spectroscopy revealed the diffusion of hydrocarbons out of the PEN substrate into the ZnO film. Hence, doped carbons may act as donors to enhance carrier concentration, and the intermixing of elements at the interface may deteriorate the crystallinity, resulting in the lower Hall mobility. When the ZnO films were thicker than 400?nm, cracks became prevalent because of the lattice mismatch strain between the film and the substrate, whereas GZO films were free of cracks. The authors investigated how rolling the films around a cylindrical pipe surface affected their conductive properties. Degraded conductivity occurred at a threshold pipe radius of 10?mm when tensile stress was applied to the film, but it occurred at a pipe radius of 5?mm when compressive stress was applied. These values are guidelines for bending actual devices fabricated on PEN substrates.

  12. Morphological and electrochemical characterization of electrodeposited ZnAg nanoparticle composite coatings

    SciTech Connect (OSTI)

    Punith Kumar, M.K.; Srivastava, Chandan, E-mail: csrivastava@materials.iisc.ernet.in

    2013-11-15T23:59:59.000Z

    Silver nanoparticles with an average size of 23 nm were chemically synthesized and used to fabricate ZnAg composite coatings. The ZnAg composite coatings were generated by electrodeposition method using a simple sulfate plating bath dispersed with 0.5, 1 and 1.5 g/l of Ag nanoparticles. Scanning electron microscopy, X-ray diffraction and texture co-efficient calculations revealed that Ag nanoparticles appreciably influenced the morphology, micro-structure and texture of the deposit. It was also noticed that agglomerates of Ag nanoparticles, in the case of high bath load conditions, produced defects and dislocations on the deposit surface. Ag nanoparticles altered the corrosion resistance property of ZnAg composite coatings as observed from Tafel polarization, electrochemical impedance analysis and an immersion test. Reduction in corrosion rate with increased charge transfer resistance was observed for ZnAg composite coatings when compared to a pure Zn coating. However, the particle concentration in the plating bath and their agglomeration state directly influenced the surface morphology and the subsequent corrosion behavior of the deposits. - Highlights: Synthesis of Ag nanoparticles with an average size of 23 nm Fabrication of Zn/nano Ag composite coating on mild steel Composite coatings showed better corrosion resistance. Optimization of particle concentration is necessary.

  13. Magnetic properties and loss separation in iron-silicone-MnZn ferrite soft magnetic composites

    SciTech Connect (OSTI)

    Wu, Shen; Sun, Aizhi; Xu, Wenhuan; Zou, Chao; Yang, Jun; Dong, Juan [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing (China)

    2013-12-16T23:59:59.000Z

    This paper investigates the magnetic and structural properties of iron-based soft magnetic composites coated with silicone-MnZn ferrite hybrid. The organic silicone resin was added to improve the flexibility of the insulated iron powder and causes better adhesion between particles to increase the mechanical properties. Scanning electron microscopy and distribution maps show that the iron particle surface is covered with a thin layer of silicone-MnZn ferrite. Silicone-MnZn ferrite coated samples have higher permeability when compared with the non-magnetic silicone resin coated compacts. The real part of permeability increases by 34.18% when compared with the silicone resin coated samples at 20 kHz. In this work, a formula for calculating the total loss component by loss separation method is presented and finally the different parts of total losses are calculated. The results show that the eddy current loss coefficient is close to each other for the silicone-MnZn ferrite, silicone resin and MnZn ferrite coated samples (0.0078Zn ferrite coated sample (k{sub 2} =1.4058) in comparison with other samples.

  14. Photoelectrochemical and photosensing behaviors of hydrothermally grown ZnO nanorods

    SciTech Connect (OSTI)

    Majumder, T.; Hmar, J. J. L.; Roy, J. N.; Mondal, S. P., E-mail: suvraphy@gmail.com, E-mail: suvra.phy@nita.ac.in [Department of Physics, National Institute of Technology, Agartala 799046 (India); Debnath, K. [Department of Electronics and Communication Engineering, National Institute of Technology, Agartala 799046 (India); Gogurla, N.; Ray, S. K. [Department of Physics, Indian Institute of Technology, Kharagpur 721302 (India)

    2014-07-21T23:59:59.000Z

    ZnO nanorods have been grown on indium-tin-oxide coated glass substrates by a low cost chemical process. Current-voltage characteristics have been studied using ZnO nanorods as photoanode in an electrochemical cell. The flat band voltage shift and depletion width of ZnO nanorods/electrolyte interface have been estimated from Mott-Schottky (MS) characteristics. The electrochemical impedance measurements have been carried out to study the charge transport mechanism at the semiconductor-electrolyte interface under dark and white light (100 mW/cm{sup 2}) illumination. The doping concentration of nanorods has been extracted from MS plot. Photoresponse behavior of ZnO nanorods is found to be enhanced than seed layers with the incident of white light. Spectral dependent photovoltage of ZnO nanorods has been carried out using monochromatic light of wavelength 250600?nm. The photopotential recovery time has been estimated for nanorods and seed layers. The stability of ZnO nanorods as a photoanode has been investigated.

  15. Sensing performances of ZnO nanostructures grown under different oxygen pressures to hydrogen

    SciTech Connect (OSTI)

    Chu, Jin; Peng, Xiaoyan [Department of Physics, University of Puerto Rico Rio Piedras, San Juan, 00936-8377 PR (United States)] [Department of Physics, University of Puerto Rico Rio Piedras, San Juan, 00936-8377 PR (United States); Wang, Zhenbo [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China)] [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Feng, Peter, E-mail: P.feng@upr.edu [Department of Physics, University of Puerto Rico Rio Piedras, San Juan, 00936-8377 PR (United States)] [Department of Physics, University of Puerto Rico Rio Piedras, San Juan, 00936-8377 PR (United States)

    2012-12-15T23:59:59.000Z

    Graphical abstract: Display Omitted Highlights: ? Surface morphology depends on the oxygen pressure. ? Structural degradation was observed for the ZnO samples when oxygen pressure was overhigh. ? The sensitivity of the ZnO-based sensors increase with grown oxygen pressure. -- Abstract: For extensive use in an industrialized process of individual ZnO nanostructures applied in gas sensors, a simple, inexpensive, and safe synthesis process is required. Here, nanostructured ZnO films were grown by a pulsed laser deposition technique under different oxygen pressures. Scanning electron microscopy images show nanopores, nanotips, and nanoparticles are obtained and energy dispersive X-ray spectroscopy data indicate oxygen concentration of the synthesized samples increases monotonously with oxygen pressure. The sensor based on ZnO with high oxygen concentration has high sensitivity, rapid response (9 s) and recovery (80 s) behavior to 500 ppm hydrogen below 150 C. Experimental data indicate that high oxygen concentration effectively improves the sensing properties of nanostructured ZnO.

  16. Magneto acoustical emission in nanocrystalline MnZn ferrites

    SciTech Connect (OSTI)

    Praveena, K., E-mail: praveenaou@gmail.com [Materials Research Centre, Indian Institute of Science, Bangalore 560012 (India); Department of Physics, Osmania University, Hyderabad 500007 (India); Murthty, S.R. [Department of Physics, Osmania University, Hyderabad 500007 (India)

    2013-11-15T23:59:59.000Z

    Graphical abstract: Mn{sub 0.4}Zn{sub 0.6}Fe{sub 2}O{sub 4} powders were prepared by microwave hydrothermal method. The powders were characterized by X-ray diffraction, transmission electron microscope. The powders were sintered at different temperatures 400, 500, 600, 700, 800 and 900 C/30 min using microwave sintering method. The grain size was estimated by scanning electron microscope. The room temperature dielectric and magnetic properties were studied in the frequency range (100 kHz1.8 GHz). The magnetization properties were measured upto 1.5 T. The acoustic emission has been measured along the hysteresis loops from 80 K to Curie temperature. It is found that the magneto-acoustic emission (MAE) activity along hysteresis loop is proportional to the hysteresis losses during the same loop. This law has been verified on series of polycrystalline ferrites and found that the law is valid whatever the composition, the grain size and temperature. It is also found that the domain wall creation/or annihilation processes are the origin of the MAE. - Highlights: The AE been measured along the hysteresis loops from 80 K to Curie temperature. The MAE activity along hysteresis loop is proportional to P{sub h} during the same loop. It is found that the domain wall creation/or annihilation processes are the origin of the MAE. - Abstract: Mn{sub 0.4}Zn{sub 0.6}Fe{sub 2}O{sub 4} powders were prepared by microwave hydrothermal method. The powders were characterized by X-ray diffraction, transmission electron microscope. The powders were sintered at different temperatures 400, 500, 600, 700, 800 and 900 C/30 min using microwave sintering method. The grain size was estimated by scanning electron microscope. The room temperature dielectric and magnetic properties were studied in the frequency range (100 kHz1.8 GHz). The magnetization properties were measured upto 1.5 T. The acoustic emission has been measured along the hysteresis loops from 80 K to Curie temperature. It is found that the magneto-acoustic emission (MAE) activity along hysteresis loop is proportional to the hysteresis losses during the same loop. This law has been verified on series of polycrystalline ferrites and found that the law is valid whatever the composition, the grain size and temperature. It is also found that the domain wall creation/or annihilation processes are the origin of the MAE.

  17. ZnO-Al2O3 and ZnO-TiO2 Core-Shell Nanowire Dye-Sensitized Solar Cells Matt Law,, Lori E. Greene,, Aleksandra Radenovic, Tevye Kuykendall,,

    E-Print Network [OSTI]

    Yang, Peidong

    ZnO-Al2O3 and ZnO-TiO2 Core-Shell Nanowire Dye-Sensitized Solar Cells Matt Law,,§ Lori E. Greene the construction and performance of dye-sensitized solar cells (DSCs) based on arrays of ZnO nanowires coated loadings through an increase in nanowire array surface area. Introduction Dye-sensitized solar cells (DSCs

  18. Aging and annealing effects on properties of Ag-N dual-acceptor doped ZnO thin films

    SciTech Connect (OSTI)

    Swapna, R.; Amiruddin, R.; Santhosh Kumar, M. C. [Advanced Materials Laboratory, Department of Physics, National Institute of Technology, Tiruchirappalli -620 015 (India)

    2013-02-05T23:59:59.000Z

    Ag-N dual acceptor doping into ZnO has been proposed to realize p-ZnO thin film of different concentrations (1, 2 and 4 at.%) by spray pyrolysis at 623 K and then 4 at.% films annealed at 673 K and 723 K for 1 hr. X-ray diffraction studies reveal that all the films are preferentially oriented along (002) plane. Energy dispersive spectroscopy (EDS) confirms the presence of Ag and N in 2 at.% ZnO:(Ag, N) film. Hall measurement shows that 4 at.% ZnO:(Ag, N) film achieved minimum resistivity with high hole concentration. The p-type conductivity of the ZnO:(Ag, N) films is retained even after 180 days. Photoluminescence (PL) spectra of ZnO:(Ag, N) films show low density of native defects.

  19. Fabrication of ZnO photonic crystals by nanosphere lithography using inductively coupled-plasma reactive ion etching with CH{sub 4}/H{sub 2}/Ar plasma on the ZnO/GaN heterojunction light emitting diodes

    SciTech Connect (OSTI)

    Chen, Shr-Jia; Chang, Chun-Ming; Kao, Jiann-Shiun; Chen, Fu-Rong; Tsai, Chuen-Horng [Engineering and System Science, National Tsing Hua University, Hsinchu, 30013 Taiwan (China); Instrument Technology Research Center, National Applied Research Laboratories, Hsinchu, 300 Taiwan (China); Engineering and System Science, National Tsing Hua University, Hsinchu, 30013 Taiwan (China)

    2010-07-15T23:59:59.000Z

    This article reports fabrication of n-ZnO photonic crystal/p-GaN light emitting diode (LED) by nanosphere lithography to further booster the light efficiency. In this article, the fabrication of ZnO photonic crystals is carried out by nanosphere lithography using inductively coupled plasma reactive ion etching with CH{sub 4}/H{sub 2}/Ar plasma on the n-ZnO/p-GaN heterojunction LEDs. The CH{sub 4}/H{sub 2}/Ar mixed gas gives high etching rate of n-ZnO film, which yields a better surface morphology and results less plasma-induced damages of the n-ZnO film. Optimal ZnO lattice parameters of 200 nm and air fill factor from 0.35 to 0.65 were obtained from fitting the spectrum of n-ZnO/p-GaN LED using a MATLAB code. In this article, we will show our recent result that a ZnO photonic crystal cylinder has been fabricated using polystyrene nanosphere mask with lattice parameter of 200 nm and radius of hole around 70 nm. Surface morphology of ZnO photonic crystal was examined by scanning electron microscope.

  20. In vitro cytotoxicity tests of ZnO?Bi{sub 2}O{sub 3}?Mn{sub 2}O{sub 3}-based varistor fabricated from ZnO micro and nanoparticle powders on L929 mouse cells

    SciTech Connect (OSTI)

    Sendi, Rabab Khalid, E-mail: last-name3@hotmail.com, E-mail: shahromx@hotmail.com, E-mail: ameerah7@hotmail.com; Mahmud, Shahrom, E-mail: last-name3@hotmail.com, E-mail: shahromx@hotmail.com, E-mail: ameerah7@hotmail.com; Munshi, Ayman, E-mail: last-name3@hotmail.com, E-mail: shahromx@hotmail.com, E-mail: ameerah7@hotmail.com [Nano-optoelectronics Research and Technology Laboratory (N.O.R.), School of Physics, Universiti Sains Malaysia, 11800, Penang (Malaysia); Seeni, Azman, E-mail: azanseeni@gmail.com [Advanced Medical and Dental Institute (AMDI), Universiti Sains Malaysia, 13200, Bertam, Pulau Pinang (Malaysia)

    2014-10-24T23:59:59.000Z

    The present study investigated the cytotoxicity of ZnO?Bi{sub 2}O{sub 3}?Mn{sub 2}O{sub 3}-varistors. To this effect, ZnO?Bi{sub 2}O{sub 3}?Mn{sub 2}O{sub 3} varistors fabricated from ZnO micro-and nanoparticle powders are prepared via conventional ceramic processing method. The effects of ZnO particle size on the properties of ZnO varistors are also investigated. The strong solid-state reaction during sintering may be attributed to the high surface area of the 20 nm ZnO nanoparticles that promote strong surface reaction. The intensity of XRD peaks reflected the high degree of crystallinity of the ZnO nanoparticles. However, the width of the peaks in case of ZnO nanoparticles has increased due to the quantum size effect. The cytotoxicity evaluation of ZnO varistor was conducted on mouse connective tissue fibroblast cells (L929) using Trypan Blue Exclusion Assay analysis. The results show that the four types of varistor samples lead to cellular mitochondrial dysfunction, morphological modifications and apoptosis at the various concentration range and the toxic effects are obviously displayed in high concentration samples. 20nm-VDR is the most toxic materials followed by 40nm-VDR, P8-VDR, and W4-VDR in a descending order.

  1. Europium substitution into intermetallic phases grown in Ca/Zn flux

    SciTech Connect (OSTI)

    Stojanovic, Milorad [Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306-4390 (United States); Latturner, Susan E., E-mail: latturne@chem.fsu.ed [Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306-4390 (United States)

    2009-08-15T23:59:59.000Z

    Replacement of calcium with europium in the phases Ca{sub 21}Ni{sub 2}Zn{sub 36} and CaNi{sub 2}Zn{sub 3} was attempted to explore the possibility of substitution in metal flux reactions and potential magnetic interactions between closely spaced Eu{sup 2+} ions. Limited substitution occurs when Eu is added to the reaction of nickel in a Ca/Zn flux mixture, up to stoichiometries of Eu{sub 5.8(3)}Ca{sub 15.2(3)}Ni{sub 2}Zn{sub 36} and Eu{sub 0.42(8)}Ca{sub 0.58(8)}Ni{sub 2}Zn{sub 3}. Structural characterization and magnetic susceptibility studies on Eu{sub x}Ca{sub 21-x}Ni{sub 2}Zn{sub 36} phases indicate that the Eu and Ca ions do not form an even solid solution on their sites, but instead segregate in separate regions of the crystals. The europium-rich regions of the samples order ferromagnetically, with T{sub C} dependent on the size of the clusters. If the concentration of Eu in the flux is raised above 20 mol%, a new compound Eu{sub 1.63(1)}Ca{sub 1.37(1)}Ni{sub 2}Zn{sub 3} (Cmcm, a=4.1150(5) A, b=16.948(2) A, c=10.302(1) A, Z=4, R{sub 1}=0.0396) is produced. - Graphical abstract: Exploration of europium substitution into intermetallic compounds grown in Ca/Zn flux has yielded analogs of Eu{sub x}Ca{sub 21-x}Ni{sub 2}Zn{sub 36} with unusual magnetic properties due to segregation of europium in the crystals; high concentrations of Eu in the flux trigger the growth of Eu{sub 1.63(1)}Ca{sub 1.37(1)}Ni{sub 2}Zn{sub 3} with a new structure type.

  2. Strain effects and band parameters in MgO, ZnO and CdO Qimin Yan,1

    E-Print Network [OSTI]

    ) would give a bandgap of 3.4 eV for wurtzite ZnO and that all previous reports of a significantly lower(cLDA) bandgap in wurtzite ZnO. The band convergence is indeed slow and the bandgap only converges when0W0@OEPx(cLDA) bandgap of wurtzite ZnO at the experimental lattice parameters on the number

  3. Optical and morphological properties of MBE grown wurtzite CdxZn1xO thin films

    E-Print Network [OSTI]

    Kik, Pieter

    Optical and morphological properties of MBE grown wurtzite CdxZn1xO thin films J.W. Mares a , F January 2007 Abstract Wurtzite CdxZn1xO epilayers with cadmium concentrations ranging from x = 0.02 to 0 wurtzite CdxZn1xO compounds for visible light emission in future optoelectronic devices. 2006 Elsevier B

  4. Hybrid structure of polyaniline/ZnO nanograss and its application in dye-sensitized solar cell with performance improvement

    SciTech Connect (OSTI)

    Zhu Shibu; Wei Wei; Chen Xiangnan [Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031 (China); Jiang Man, E-mail: jiangman1021@163.com [Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031 (China); Zhou Zuowan, E-mail: zwzhou@at-c.net [Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031 (China)

    2012-06-15T23:59:59.000Z

    Polyaniline (PANI) hybridized ZnO photoanode for dye-sensitized solar cell (DSSC) was primarily prepared via a two-step process which involved hydrothermal growth of ZnO nanograss on the fluorine-doped tin oxide (FTO) substrate and subsequently chemisorption of PANI on the surfaces of the ZnO nanorods. The PANI hybridized ZnO nanograss films were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectra (FT-IR), and the results indicated that there were chemical interactions between PANI and ZnO. Both pure ZnO nanograss and PANI hybridized ZnO nanograss were applied to DSSC. The results of photoelectrochemical measurement showed that the photocurrent density of PANI (100 mg/L) hybridized ZnO nanograss photoanode was significantly enhanced, and the overall light-conversion efficiency increased by 60%. The electrochemical impedance spectra (EIS) displayed that the electron densities in photoanodes of PANI hybridized ZnO nanograss were larger than that in pure ZnO nanograss. This is ascribed to more effective charge separation and faster interfacial charge transferring occurred in the hybrid photoanode. - Graphical abstract: Operational principle of the DSSC: the introduced hybridizing PANI layer performs effective charge separation and faster interfacial charge transferring. Highlights: Black-Right-Pointing-Pointer PANI/ZnO nanograss hybrid materials as photoanode in Dye-sensitized solar cell. Black-Right-Pointing-Pointer Photoelectric conversion efficiency after hybridization was enhanced by 60%. Black-Right-Pointing-Pointer PANI hybridizing ZnO nanograss induced a rapid charge separation.

  5. Multichannel CdZnTe Gamma Ray Spectrometer

    SciTech Connect (OSTI)

    F. P. Doty; C. L. Lingren; B. A. Apotovsky; J. Brunsch; J. F. Butler; T. Collins; R. L. Conwell; S. Friesenhahn; J. Gormley; B. Pi; S. Zhao (Digirad Corp., San Diego, CA); F. L. Augustine, Augustine Engineering, Encinitas, CA; B. A. Bennet; E. Cross; R. B. James (Sandia Nat'l. Labs.)

    1998-07-22T23:59:59.000Z

    A 3 cm{sup 3} multichannel gamma spectrometer for DOE applications is under development by Digirad Corporation. The device is based on a position sensitive detector packaged in a compact multi-chip module (MCM) with integrated readout circuitry. The modular, multichannel design will enable identification and quantitative analysis of radionuclides in extended sources, or sources containing low levels of activity. The MCM approach has the advantages that the modules are designed for imaging applications, and the sensitivity can be arbitrarily increased by increasing the number of pixels, i.e. adding modules to the instrument. For a high sensitivity probe, the outputs for each pixel can be corrected for gain and offset variations, and summed digitally. Single pixel results obtained with discrete low noise readout indicate energy resolution of 3 keV can be approached with currently available CdZnTe. The energy resolution demonstrated to date with MCMs for 511 keV gamma rays is 10 keV.

  6. Prototype Imaging Cd-Zn-Te Array Detector

    E-Print Network [OSTI]

    P. F. Bloser; T. Narita; J. E. Grindlay; K. Shah

    1998-01-15T23:59:59.000Z

    We describe initial results of our program to develop and test Cd-Zn-Te (CZT) detectors with a pixellated array readout. Our primary interest is in the development of relatively thick CZT detectors for use in astrophysical coded aperture telescopes with response extending over the energy range $\\sim 10-600$ keV. The coded aperture imaging configuration requires only relatively large area pixels (1-3 mm), whereas the desired high energy response requires detector thicknesses of at least 3-5 mm. We have developed a prototype detector employing a 10 x 10 x 5 mm CZT substrate and 4 x 4 pixel (1.5 mm each) readout with gold metal contacts for the pixels and continuous gold contact for the bias on the opposite detector face. This MSM contact configuration was fabricated by RMD and tested at Harvard for uniformity, efficiency and spatial as well as spectral resolution. We have developed an ASIC readout (IDE-VA-1) and analysis system and report results, including $\\sim 4$% (FWHM) energy resolution at 60 keV. A prototype design for a full imaging detector array is discussed.

  7. Strain relaxation by dislocation glide in ZnO/ZnMgO core-shell nanowires G. Perillat-Merceroz,1, 2, a)

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    deposited on ZnO nanowires. Strain along the a and c axes of the wurtzite structure is relaxed through have been calculated for cubic17 and wurtzite16 structures. For wurtzite mate- rials, the strain energy of wurtzite InAs/GaAs core-shell nanowires.18,19 How- ever, there are no indications of dislocations threading

  8. Enhanced photovoltaic performance of nanocrystalline CdTe/ZnO solar cells using sol-gel ZnO and positive bias treatment

    SciTech Connect (OSTI)

    MacDonald, B. I. [CSIRO Materials Science and Engineering, Bayview Avenue, Clayton, Victoria 3168 (Australia); School of Chemistry and Bio21 Institute, The University of Melbourne, Parkville, Victoria 3010 (Australia); Della Gaspera, E.; Watkins, S. E.; Jasieniak, J. J., E-mail: Jacek.Jasieniak@csiro.au [CSIRO Materials Science and Engineering, Bayview Avenue, Clayton, Victoria 3168 (Australia); Mulvaney, P. [School of Chemistry and Bio21 Institute, The University of Melbourne, Parkville, Victoria 3010 (Australia)

    2014-05-14T23:59:59.000Z

    The effect of doping and porosity of the n-type ZnO layer on the performance of solution-processed, sintered p-CdTe/n-ZnO nanocrystal photovoltaic (PV) devices is investigated. Amorphous sol-gel ZnO is found to be the best candidate with overall energy conversion efficiencies above 8% obtained if the ZnO is also indium doped. We demonstrate that when such PV devices are left under forward bias (in dark or light), the device efficiency values are raised to at least 9.8%, due to a substantially increased open-circuit voltage and fill-factor. This drastic enhancement is attributed to improved band alignment at the ITO/CdTe interface. The forward-bias treatment is slowly reversed over a period of days to weeks on standing under open circuit conditions, but is readily restored with further voltage treatment. The moderate processing conditions and high efficiency of such devices demonstrate that nanocrystal-based systems are a promising technology for photovoltaics.

  9. Band alignment of epitaxial ZnS/Zn3P2 heterojunctions Jeffrey P. Bosco, Steven B. Demers, Gregory M. Kimball, Nathan S. Lewis, and Harry A. Atwater

    E-Print Network [OSTI]

    Kimball, Gregory

    ) Determination of the deep donor-like interface state density distribution in metal/Al2O3/n-GaN structures from phosphide (a- Zn3P2) has a nearly optimal, direct band gap of 1.50 eV and a high visible-light absorption

  10. The Effect Of ZnO Addition On Co/C Catalyst For Vapor And Aqueous Phase Reforming Of Ethanol

    SciTech Connect (OSTI)

    Davidson, Stephen; Sun, Junming; Hong, Yongchun; Karim, Ayman M.; Datye, Abhaya K.; Wang, Yong

    2014-02-05T23:59:59.000Z

    The effect of ZnO addition on the oxidation behavior of Co along with catalytic performance in vapor and aqueous phase reforming of ethanol were investigated on Co supported on carbon black (XC-72R). Carbon was selected to minimize the support interactions. Effect of ZnO addition during both vapor and aqueous phase reforming were compared at 250 C. ZnO addition inhibited the reduction of cobalt oxides by H2 and created surface sites for H2O activation. During vapor phase reforming at 450 C the redox of cobalt, driven by steam oxidation and H2 reduction, trended to an equilibrium of Co0/Co2+. ZnO showed no significant effect on cobalt oxidation, inferred from the minor changes of C1 product yield. Surface sites created by ZnO addition enhanced water activation and oxidation of surface carbon species, increasing CO2 selectivity. At 250 C cobalt reduction was minimal, in situ XANES demonstrated that ZnO addition significantly facilitated oxidation of Co0 under vapor phase reforming conditions, demonstrated by lower C1 product yield. Sites introduced by ZnO addition improved the COx selectivity at 250 C. Both Co/C and Co-ZnO/C rapidly oxidized under aqueous phase reaction conditions at 250 C, showing negligible activity in aqueous phase reforming. This work suggests that ZnO affects the activation of H2O for Co catalysts in ethanol reforming.

  11. A comparison of ZnO films deposited on indium tin oxide and soda lime glass under identical conditions

    SciTech Connect (OSTI)

    Deka, Angshuman; Nanda, Karuna Kar [Materials Research Centre, Indian Institute of Science, Bangalore - 560012 (India)

    2013-06-15T23:59:59.000Z

    ZnO films have been grown via a vapour phase transport (VPT) on soda lime glass (SLG) and indium-tin oxide (ITO) coated glass. ZnO film on ITO had traces of Zn and C which gives them a dark appearance while that appears yellowish-white on SLG. X-ray photoelectron spectroscopy studies confirm the traces of C in the form of C-O. The photoluminescence studies reveal a prominent green luminescence band for ZnO film on ITO.

  12. The preparation of zinc silicate/ZnO particles and their use as an efficient UV absorber

    SciTech Connect (OSTI)

    Podbrscek, Peter [National Institute of Chemistry, Hajdrihova 19, SI 1000 Ljubljana (Slovenia)] [National Institute of Chemistry, Hajdrihova 19, SI 1000 Ljubljana (Slovenia); Drazic, Goran [Department for Nanostructured Materials, Jozef Stefan Institute, Jamova 39, SI 1000 Ljubljana (Slovenia)] [Department for Nanostructured Materials, Jozef Stefan Institute, Jamova 39, SI 1000 Ljubljana (Slovenia); Anzlovar, Alojz [National Institute of Chemistry, Hajdrihova 19, SI 1000 Ljubljana (Slovenia) [National Institute of Chemistry, Hajdrihova 19, SI 1000 Ljubljana (Slovenia); Center of Excellence for Polymer Materials and Technologies, Tehnoloski Park 24, 1000 Ljubljana (Slovenia); Orel, Zorica Crnjak, E-mail: zorica.crnjak.orel@ki.si [National Institute of Chemistry, Hajdrihova 19, SI 1000 Ljubljana (Slovenia); Center of Excellence for Polymer Materials and Technologies, Tehnoloski Park 24, 1000 Ljubljana (Slovenia)

    2011-11-15T23:59:59.000Z

    Highlights: {yields} We used innovative gel-route in order to prepare zinc silicate/ZnO nano-particles. {yields} Continuous reactor was efficient for synthesizing ZnO and zinc silicate/ZnO precursors. {yields} Introduction of Si into reaction mixture influenced on particle size and their photoactivity. {yields} Prepared particles are appropriate for UV absorbers in polymers. -- Abstract: The formation of zinc silicate/ZnO particles synthesized by a two-step method and their incorporation into PMMA is presented. In the first step a segmented-flow tubular reactor was used for the continuous room-temperature preparation of a zinc silicate/Zn(OH){sub 2} gel that was thermally treated after rinsing and drying in the second step. The same preparation procedure was also employed for the synthesis of pure ZnO and pure zinc silicate particles. It was found that the presence of the zinc silicate phase significantly influenced the final particle size, decreased the degree of crystallization and reduced the particles' UV absorption capabilities. The reduced photocatalytic activity of the zinc silicate/ZnO particles indicated that the majority of ZnO crystallites were formed inside the zinc silicate matrix. The nanocomposite prepared from zinc silicate/ZnO particles (0.04 wt.%) and PMMA showed high UV shielding and at the same time sufficient transmittance in the visible-light region.

  13. Phase relations and crystal structures in the system Ce-Ni-Zn at 800 Degree-Sign C

    SciTech Connect (OSTI)

    Malik, Z.; Grytsiv, A. [Institute of Physical Chemistry, University of Vienna, Waehringerstrasse 42, A-1090 Vienna (Austria)] [Institute of Physical Chemistry, University of Vienna, Waehringerstrasse 42, A-1090 Vienna (Austria); Rogl, P., E-mail: peter.franz.rogl@univie.ac.at [Institute of Physical Chemistry, University of Vienna, Waehringerstrasse 42, A-1090 Vienna (Austria); Giester, G. [Institute of Mineralogy and Crystallography, University of Vienna, Althanstrasse 14, A-1090 Vienna (Austria)] [Institute of Mineralogy and Crystallography, University of Vienna, Althanstrasse 14, A-1090 Vienna (Austria)

    2012-10-15T23:59:59.000Z

    Phase relations have been established for the system Ce-Ni-Zn in the isothermal section at 800 Degree-Sign C using electron microprobe analysis and X-ray powder diffraction. Phase equilibria at 800 Degree-Sign C are characterized by a large region for the liquid phase covering most of the Ce-rich part of the diagram, whereas a Zn-rich liquid is confined to a small region near the Zn-corner of the Gibbs triangle. Whereas solubility of Ce in the binary Ni-Zn phases is negligible, mutual solubilities of Ni and Zn at a constant Ce content are large at 800 Degree-Sign C for most Ce-Zn and Ce-Ni compounds. The solid solution Ce(Ni{sub 1-x}Zn{sub x}){sub 5} with the CaCu{sub 5}-type is continuous throughout the entire section and for the full temperature region from 400 to 800 Degree-Sign C. Substitution of Zn by Ni is found to stabilize the structure of CeZn{sub 11} to higher temperatures. At 800 Degree-Sign C Ce(Ni{sub x}Zn{sub 1-x}){sub 11} (0.03{<=}x{<=}0.22) appears as a ternary solution phase. Similarly, a rather extended solution forms for Ce{sub 2}(Ni{sub x}Zn{sub 1-x}){sub 17} (0{<=}x{<=}0.53). Detailed data on atom site occupation and atom parameters were derived from X-ray structure analyses for single crystals of Ce{sub 2+y}(Ni{sub x}Zn{sub 1-x}){sub 17}, y=0.02, x=0.49 (a=0.87541(3), c=1.25410(4) nm; Th{sub 2}Zn{sub 17} type with space group R3{sup Macron }m,R{sub F{sup 2}}=0.018) and Ce(Ni{sub 0.18}Zn{sub 0.82}){sub 11} (a=1.04302(2), c=0.67624(3)nm, BaCd{sub 11} type with space group I4{sub 1}/amd, R{sub F{sup 2}}=0.049). - Graphical abstract: Ce-Ni-Zn isothermal section at 800 Degree-Sign C. Highlights: Black-Right-Pointing-Pointer Phase relations were determined for the system Ce-Ni-Zn in the section at 800 Degree-Sign C. Black-Right-Pointing-Pointer A continuous solid solution Ce(Ni{sub 1-x}Zn{sub x}){sub 5}, 0{<=}x{<=}1, forms between 400 and 800 Degree-Sign C. Black-Right-Pointing-Pointer Zn/Ni substitution stabilizes the ternary phase Ce(Zn{sub 1-x}Ni{sub x}){sub 11}, 0.03{<=}x{<=}0.22, 800 Degree-Sign C. Black-Right-Pointing-Pointer An extended solution forms for Ce{sub 2}(Ni{sub x}Zn{sub 1-x}){sub 17} (0{<=}x{<=}0.53). Black-Right-Pointing-Pointer Crystal data are given: Ce{sub 2+y}(Ni{sub x}Zn{sub 1-x}){sub 17} (Th{sub 2}Zn{sub 17}), Ce(Ni{sub 0.18}Zn{sub 0.82}){sub 11} (BaCd{sub 11}).

  14. Copper doping of ZnO crystals by transmutation of {sup 64}Zn to {sup 65}Cu: An electron paramagnetic resonance and gamma spectroscopy study

    SciTech Connect (OSTI)

    Recker, M. C.; McClory, J. W., E-mail: John.McClory@afit.edu; Holston, M. S.; Golden, E. M.; Giles, N. C. [Department of Engineering Physics, Air Force Institute of Technology, Wright-Patterson Air Force Base, Ohio 45433 (United States); Halliburton, L. E. [Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506 (United States)

    2014-06-28T23:59:59.000Z

    Transmutation of {sup 64}Zn to {sup 65}Cu has been observed in a ZnO crystal irradiated with neutrons. The crystal was characterized with electron paramagnetic resonance (EPR) before and after the irradiation and with gamma spectroscopy after the irradiation. Major features in the gamma spectrum of the neutron-irradiated crystal included the primary 1115.5?keV gamma ray from the {sup 65}Zn decay and the positron annihilation peak at 511?keV. Their presence confirmed the successful transmutation of {sup 64}Zn nuclei to {sup 65}Cu. Additional direct evidence for transmutation was obtained from the EPR of Cu{sup 2+} ions (where {sup 63}Cu and {sup 65}Cu hyperfine lines are easily resolved). A spectrum from isolated Cu{sup 2+} (3d{sup 9}) ions acquired after the neutron irradiation showed only hyperfine lines from {sup 65}Cu nuclei. The absence of {sup 63}Cu lines in this Cu{sup 2+} spectrum left no doubt that the observed {sup 65}Cu signals were due to transmuted {sup 65}Cu nuclei created as a result of the neutron irradiation. Small concentrations of copper, in the form of Cu{sup +}-H complexes, were inadvertently present in our as-grown ZnO crystal. These Cu{sup +}-H complexes are not affected by the neutron irradiation, but they dissociate when a crystal is heated to 900?C. This behavior allowed EPR to distinguish between the copper initially in the crystal and the copper subsequently produced by the neutron irradiation. In addition to transmutation, a second major effect of the neutron irradiation was the formation of zinc and oxygen vacancies by displacement. These vacancies were observed with EPR.

  15. In Situ XRD Studies of ZnO/GaN Mixtures at High Pressure and High Temperature: Synthesis of Zn-Rich (Ga1-xZnx)(N1-xOx) Photocatalysts

    SciTech Connect (OSTI)

    Chen, H.; Wang, L; Bai, J; Hanson, J; Warren, J; Muckerman, J; Fujita, E; Rodriguez, J

    2010-01-01T23:59:59.000Z

    The high-pressure, high-temperature conditions for the synthesis of Zn-rich (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solutions from mixtures of ZnO/GaN were explored using synchrotron-based in situ time-resolved X-ray diffraction (XRD). Following a new synthetic path, (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solutions with a Zn content up to {approx}75% were prepared for the first time. The structures of the (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solutions were characterized by XRD and X-ray absorption fine structure (XAFS) analyses and were in excellent agreement with the predictions of density functional calculations. These materials adopt a wurtzite crystal structure with metal-N or metal-O bond distances in the range of 1.95-1.98 {angstrom}. Although the (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solutions seem to be stable over the full range of compositions, no ideal solid solution formation was observed. In all cases, the lattice parameters were larger than those of ideal solid solutions. The variation of the lattice parameter c showed an upward double bowing curve, as was predicted by theoretical calculations. Also, no ideal behavior was observed in the electronic properties of the (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solutions. X-ray absorption spectra at the Zn and Ga K-edges of the (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) systems showed significant electronic perturbations with respect to ZnO and GaN. The synthesized (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solution with a Zn content of 50% displayed the ability to absorb visible light well above 500 nm. This material has a great potential for splitting water under visible light irradiation. The availability of (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solutions with a high Zn content opens the door to fully explore the application of these materials in photocatalysis.

  16. In Situ XRD Studies of ZnO/GaN Mixtures at High Pressure and High Temperature: Synthesis of Zn-Rich (Ga1-xZnx)(N1-xOx) Photocatalysts

    SciTech Connect (OSTI)

    Rodriguez, J.A.; Chen, H.; Wang, L.; Bai, J.; Hanson, J.C.; Warren, J.B.; Muckerman, J.T.; Fujita, E.

    2010-02-04T23:59:59.000Z

    The high-pressure, high-temperature conditions for the synthesis of Zn-rich (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solutions from mixtures of ZnO/GaN were explored using synchrotron-based in situ time-resolved X-ray diffraction (XRD). Following a new synthetic path, (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solutions with a Zn content up to 75% were prepared for the first time. The structures of the (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solutions were characterized by XRD and X-ray absorption fine structure (XAFS) analyses and were in excellent agreement with the predictions of density functional calculations. These materials adopt a wurtzite crystal structure with metal-N or metal-O bond distances in the range of 1.95-1.98 {angstrom}. Although the (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solutions seem to be stable over the full range of compositions, no ideal solid solution formation was observed. In all cases, the lattice parameters were larger than those of ideal solid solutions. The variation of the lattice parameter c showed an upward double bowing curve, as was predicted by theoretical calculations. Also, no ideal behavior was observed in the electronic properties of the (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solutions. X-ray absorption spectra at the Zn and Ga K-edges of the (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) systems showed significant electronic perturbations with respect to ZnO and GaN. The synthesized (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solution with a Zn content of 50% displayed the ability to absorb visible light well above 500 nm. This material has a great potential for splitting water under visible light irradiation. The availability of (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solutions with a high Zn content opens the door to fully explore the application of these materials in photocatalysis.

  17. Interdiffusion and impurity diffusion in polycrystalline Mg solid solution with Al or Zn

    SciTech Connect (OSTI)

    Kammerer, Catherine [University of Central Florida, Orlando; Kulkarni, Nagraj S [ORNL; Warmack, Robert J Bruce [ORNL; Sohn, Yong Ho [University of Central Florida

    2014-01-01T23:59:59.000Z

    Interdiffusion and impurity diffusion in Mg binary solid solutions, Mg(Al) and Mg(Zn) were investigated at temperatures ranging from 623 to 723 K. Interdiffusion coef cients were determined via the Boltzmann Matano Method using solid-to-solid diffusion couples assembled with polycrystalline Mg and Mg(Al) or Mg(Zn) solid solutions. In addition, the Hall method was employed to extrapolate the impurity diffusion coef cients of Al and Zn in pure polycrystalline Mg. For all diffusion couples, electron micro-probe analysis was utilized for the measurement of concentration pro les. The interdiffusion coef cient in Mg(Zn) was higher than that of Mg(Al) by an order of magnitude. Additionally, the interdiffusion coef cient increased signi cantly as a function of Al content in Mg(Al) solid solution, but very little with Zn content in Mg(Zn) solid solution. The activation energy and pre-exponential factor for the average effective interdiffusion coef cient in Mg(Al) solid solution were determined to be 186.8 ( 0.9) kJ/mol and 7.69 x 10-1 ( 1.80 x 10-1) m2/s, respectively, while those determined for Mg(Zn) solid solution were 139.5 ( 4.0) kJ/mol and 1.48 x 10-3 ( 1.13 x 10-3) m2/s. In Mg, the Zn impurity diffusion coef cient was an order of magnitude higher than the Al impurity diffusion coef cient. The activation energy and pre-exponential factor for diffusion of Al impurity in Mg were determined to be 139.3 ( 14.8) kJ/mol and 6.25 x 10-5 ( 5.37 x 10-4) m2/s, respectively, while those for diffusion of Zn impurity in Mg were determined to be 118.6 ( 6.3) kJ/mol and 2.90 x 10-5 ( 4.41 x 10-5) m2/s.

  18. Electroluminescence from ZnO/Si heterojunctions fabricated by PLD with bias voltage application

    SciTech Connect (OSTI)

    Seno, Yuuki; Konno, Daisuke; Komiyama, Takao; Chonan, Yasunori; Yamaguchi, Hiroyuki; Aoyama, Takashi [Electronics and Information Systems, Akita Prefectural Univ. Yuri-honjo, Akita 015-0055 (Japan)

    2014-02-21T23:59:59.000Z

    Electroluminescence (EL) for ZnO films has been investigated by fabricating n-ZnO/p-Si heterojunctions and changing the VI/II (O/Zn) ratio of the films. In the photoluminescence (PL) spectra, both the near band edge (NBE) emission and the defect-related emission were observed, while in the EL spectra only defect-related emission was observed. The EL spectra were divided into three components: green (550 nm), yellow (618 nm) and red (700 nm) bands; and their intensities were compared. As the VI/II (O/Zn) ratio was increased, the red band emission intensity decreased and the green band emission intensity increased. This implies that the oxygen and the zinc vacancies are related to the red and the green band emissions, respectively. Electron transitions from the conduction band minimum (Ec) to the deep energy levels of these vacancies are suggested to cause the red and the green luminescences while the energy levels of the Zn interstitials are close to the Ec in the band gap and no NBE emission is observed.

  19. Emission dynamics of an expanding ultrafast-laser produced Zn plasma under different ambient pressures

    SciTech Connect (OSTI)

    Smijesh, N.; Philip, Reji [Raman Research Institute, C.V. Raman Avenue, Sadashivanagar, Bangalore 560080 (India)] [Raman Research Institute, C.V. Raman Avenue, Sadashivanagar, Bangalore 560080 (India)

    2013-09-07T23:59:59.000Z

    We report time and space resolved spectral measurements of neutral Zn emission from an ultrafast laser produced plasma, generated by the irradiation of a Zn target with laser pulses of 100 femtoseconds duration, carried out in a broad ambient pressure range of 0.05 to 100 Torr. The measurement is done for three different axial positions in the expanding plume. The spectra are rich in neutral Zn (Zn I) emissions at 334.5 nm, 468 nm, 472 nm, 481 nm, and 636 nm, respectively, depicting the characteristic triplet structure of Zn. Fast as well as slow peaks are observed in the time of flight data of 481 nm emission, which arise from recombination and atomic contributions, respectively, occurring at different time scales. Average speeds of the fast atomic species do not change appreciably with ambient pressure. The plasma parameters (electron temperature and number density) are evaluated from the measured optical emission spectra. The rates of ionization and recombination can be enhanced by a double-pulse excitation configuration in which optical energy is coupled to the ultrafast plasma through a delayed laser pulse.

  20. Dynamic recrystallization and texture evolution of MgYZn alloy during hot extrusion process

    SciTech Connect (OSTI)

    Tong, L.B. [State Key Laboratory of Rare Earth Resources Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Li, X. [Institut fr Metallkunde und Metallphysik, RWTH-Aachen University, D-52056 Aachen (Germany); Guangzhou Research Institute of Non-ferrous Metals, Guangzhou 510651 (China); Zhang, D.P.; Cheng, L.R.; Meng, J. [State Key Laboratory of Rare Earth Resources Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Zhang, H.J., E-mail: hongjie@ciac.ac.cn [State Key Laboratory of Rare Earth Resources Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

    2014-06-01T23:59:59.000Z

    The microstructure and texture evolution of Mg{sub 98.5}Y{sub 1}Zn{sub 0.5} and Mg{sub 92.5}Y{sub 5}Zn{sub 2.5} (atomic percent) alloys during hot extrusion were systematically investigated. The coarse LPSO phases with higher volume fraction (? 57%) suppressed the twinning generation in the initial stage of extrusion, and accelerated the dynamic recrystallization through the particle deformation zones. Therefore, the volume fraction of DRXed grains in as-extruded Mg{sub 92.5}Y{sub 5}Zn{sub 2.5} alloy was much higher than that of Mg{sub 98.5}Y{sub 1}Zn{sub 0.5} alloy. The intensive recrystallization process resulted in the conventional basal texture weakening, although the texture evolution was mainly dominated by flow behavior. The dynamic recrystallization behavior in Mg{sub 92.5}Y{sub 5}Zn{sub 2.5} alloy restricted the formation of deformation texture, and thus the more random texture was observed during the whole extrusion process. - Highlights: The densely coarse LPSO phases suppressed the twinning deformation. Coarse LPSO phases induced the particle stimulated nucleation effect. Dynamic recrystallization resulted in the basal texture weakening effect.

  1. Cu2ZnSnS x O4 x and Cu2ZnSnS x Se4 x : First principles simulations of optimal alloy configurations and their energies

    E-Print Network [OSTI]

    Holzwarth, Natalie

    .1063/1.4819206 The role of secondary phase precipitation on grain boundary electrical activity in Cu2ZnSnS4 (CZTS in thin film solar cells, multicomponent copper chalcogenide based com- pounds, namely, Cu2ZnSnS4(CZTS sulphide CZTS device has reported an efficiency of 8.4%,5 whereas the best pure selenide CZTSe device has

  2. FINAL REPORT OF RESEARCH ON CuxS/ (Cd,Zn)S PHOTOVOLTAIC SOLAR ENERGY CONVERTERS 3/77 - 9/79

    E-Print Network [OSTI]

    Chin, B.L.

    2013-01-01T23:59:59.000Z

    and (Cd,Zn)S/CuxS photovoltaic cells. The approach was tothe CuxS/(Cd,Zn)S photovoltaic cell in order to betterstudying CdS/CuxS photovoltaic cells, films prepared by the

  3. A Novel and Functional Single Layer Sheet of ZnSe

    SciTech Connect (OSTI)

    Zhou, Jia [ORNL; Sumpter, Bobby G [ORNL; Kent, Paul R [ORNL; Huang, Jingsong [ORNL

    2015-01-01T23:59:59.000Z

    In this Communication, we report a novel singlelayer sheet of ZnSe, with a three-atomic thickness, which demonstrates a strong quantum confinement effect by exhibiting a large blue shift of 2.0 eV in its absorption edge relative to the zinc blende (ZB) bulk phase. Theoretical optical absorbance shows that the largest absorption of this ultrathin single-layer sheet of ZnSe occurs at a wavelength similar to its four-atom-thick doublelayer counterpart but with higher photoabsorption efficiency, suggesting a superior behavior on incident photon-to-current conversion efficiency for solar water splitting, among other potential applications. The results presented herein for ZnSe may be generalized to other group II-VI analogues.

  4. Tunable mechanical and thermal properties of ZnS/CdS core/shell nanowires

    E-Print Network [OSTI]

    Mandal, Taraknath; Maiti, Prabal K

    2015-01-01T23:59:59.000Z

    Using all atom molecular dynamics (MD) simulations, we have studied the mechanical properties of ZnS/CdS core/shell nanowires. Our results show that the coating of a few atomic layer CdS shell on the ZnS nanowire leads to a significant change in the stiffness of the core/shell nanowires compared to the stiffness of pure ZnS nanowires. The binding energy between the core and shell region decreases due to the lattice mismatch at the core-shell interface. This reduction in binding energy plays an important role in determining the stiffness of a core/shell nanowire. We have also investigated the effects of the shell on the thermal conductivity and melting behavior of the nanowires.

  5. Homojunction p-n photodiodes based on As-doped single ZnO nanowire

    SciTech Connect (OSTI)

    Cho, H. D.; Zakirov, A. S.; Yuldashev, Sh. U.; Kang, T. W. [Quantum-Functional Semiconductor Research Center, Dongguk Univ.-Seoul, Seoul 100-715 (Korea, Republic of); Ahn, C. W. [Nano-materials Lab. National Nanofab Center at KAIST, 335 Gwahangno, Daejeon 305-806 (Korea, Republic of); Yeo, Y. K. [Department of Engineering Physics, Air Force Institute of Technology,Wright-Patterson AFB, OH 45433 (United States)

    2013-12-04T23:59:59.000Z

    Photovoltaic device was successfully grown solely based on the single ZnO p-n homojunction nanowire. The ZnO nanowire p-n diode consists of an as-grown n-type segment and an in-situ arsenic doped p-type segment. This p-n homojunction acts as a good photovoltaic cell, producing a photocurrent almost 45 times larger than the dark current under reverse-biased condition. Our results demonstrate that present ZnO p-n homojunction nanowire can be used as a self-powered ultraviolet photodetector as well as a photovoltaic cell, which can also be used as an ultralow electrical power source for nano-scale electronic, optoelectronic, and medical devices.

  6. Reliable self-powered highly spectrum-selective ZnO ultraviolet photodetectors

    SciTech Connect (OSTI)

    Shen, H. [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China) [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Shan, C. X., E-mail: shancx@ciomp.ac.cn, E-mail: binghuili@163.com; Li, B. H., E-mail: shancx@ciomp.ac.cn, E-mail: binghuili@163.com; Shen, D. Z. [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China)] [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); Xuan, B. [Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China)] [Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China)

    2013-12-02T23:59:59.000Z

    Ultraviolet photodetectors (PDs) have been fabricated from p-ZnO:(Li,N)/n-ZnO structures in this Letter. The PDs can operate without any external power supply and show response only to a very narrow spectrum range. The self-power character of the devices is due to the built-in electric field in the p-n junctions that can separate the photogenerated electrons and holes while the high spectrum-selectivity has been attributed to the filter effect of the neutral region in the ZnO:(Li,N) layer. The performance of the self-powered highly spectrum-selective PDs degrades little after five months, indicating their good reliability.

  7. Far-infrared optical and dielectric response of ZnS measured by terahertz time-domain spectroscopy

    E-Print Network [OSTI]

    Far-infrared optical and dielectric response of ZnS measured by terahertz time-domain spectroscopy material in the infrared and far-infrared region.1 It plays a vital role in being used as infrared windows the frequency-dependent optical properties and complex di- electric response of ZnS over a broad far-infrared

  8. Effect of Pre-Aging on the Microstructure and Strength of Supersaturated AlZnMg Alloys Processed by ECAP

    E-Print Network [OSTI]

    Gubicza, Jen

    Effect of Pre-Aging on the Microstructure and Strength of Supersaturated AlZnMg Alloys Processed-059 Krakw, Poland 3 Departments of Aerospace & Mechanical Engineering and Materials Science, University langdon@usc.edu Keywords: Supersaturated AlZnMg alloys, natural aging, Guinier-Prestion zones, Equal

  9. Absorption spectra of CdSe-ZnS core-shell quantum dots at high photon energies : experiment and modeling

    E-Print Network [OSTI]

    Ghosh, Sandip

    Absorption spectra of CdSe-ZnS core-shell quantum dots at high photon energies : experiment spectra of CdSe-ZnS core-shell quantum dot (QD) ensembles, with average core diameters ranging from 2.6 nm. In agreement with previous reports, the absorption coefficient at energies 1 eV above the effective bandgap

  10. Optical spectra of ZnO in the far ultraviolet: First-principles calculations and ellipsometric measurements

    E-Print Network [OSTI]

    Nabben, Reinhard

    February 2010; published 19 March 2010 We present ellipsometry data of the dielectric function of wurtzite anisotropy above 10 eV, a feature for which ZnO deviates from the other II-VI wurtzite compounds on the optical response of bulk wurtzite wz ZnO, reporting ellipsometric measurements in the far UV. Ellipsometry

  11. Controlled synthesis and manipulation of ZnO nanorings and nanobows William L. Hughes and Zhong L. Wanga

    E-Print Network [OSTI]

    Wang, Zhong L.

    Controlled synthesis and manipulation of ZnO nanorings and nanobows William L. Hughes and Zhong L An experimental procedure is presented for the controlled synthesis and manipulation of ZnO nanorings and nanobows at high purity and large yield. Atomic force microscopy manipulation of the nanostructures demonstrates

  12. Dissolved trace metals (Ni, Zn, Co, Cd, Pb, Al, and Mn) around the Crozet Islands, Southern Ocean

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    of trace elements such as Zn, Co, and Cd may be influenced by complexing ligands [e.g., Zn: Bruland, 1989; Ellwood and van den Berg, 2000; Co: Ellwood and van den Berg, 2001; Saito et al., 2004; Cd: Bruland, 1992

  13. Temperature dependence of magnetic behaviour in very fine grained, spark plasma sintered NiCuZn Ferrites

    E-Print Network [OSTI]

    Boyer, Edmond

    CuZn Ferrites Behzad Ahmadi,1, a) Karim Zehani,1 Martino LoBue,1 Vincent Loyau,1 and Frederic Mazaleyrat1 SATIE spark plasma sintering technique, a family of very fine grained, fully dense NiCuZn ferrites have been produced which show constant permeability up to several 10 MHz. These Ferrites can be used for filtering

  14. Growth of Single-and Bilayer ZnO on Au(111) and Interaction with Xingyi Deng,*,,,

    E-Print Network [OSTI]

    Li, Weixue

    Growth of Single- and Bilayer ZnO on Au(111) and Interaction with Copper Xingyi Deng,*,,, Kun Yao of Sciences, Dalian 116023, China URS, P.O. Box 618, South Park, Pennsylvania 15129, United States *S for the structure of the grown ultrathin ZnO, in particular how important the interaction between the substrate

  15. Effet de l'apport de phosphore, de carbonate de calcium et d'oligo-lments (Cu, Mn, Zn, B)

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    Agronomie Effet de l'apport de phosphore, de carbonate de calcium et d'oligo-lments (Cu, Mn, Zn apports de phosphore, de carbonate de calcium et d'oligo-lments (Mn, Cu, Zn, B), en vue de mieux celles de B lorsqu'on lve le pH par apport de carbonate de calcium; - l'accumulation prfrentielle de

  16. Substrate Atomic-Termination-Induced Anisotropic Growth of ZnO Nanowires/Nanorods by the VLS Process

    E-Print Network [OSTI]

    Wang, Zhong L.

    Substrate Atomic-Termination-Induced Anisotropic Growth of ZnO Nanowires/Nanorods by the VLSO substrate, we demonstrate the effect of substrate surface termination on nanowire growth. Symmetric) substrates have asymmetrically grown nanostructures. For the Zn-terminated (0001) substrate surface, uniform

  17. DOI: 10.1002/adma.200602927 Hierarchically Structured ZnO Film for Dye-Sensitized Solar Cells

    E-Print Network [OSTI]

    Cao, Guozhong

    DOI: 10.1002/adma.200602927 Hierarchically Structured ZnO Film for Dye-Sensitized Solar Cells* The interest in dye-sensitized solar cells has increased due to reduced energy sources and higher energy, zinc oxide (ZnO) has recently been explored as an alternative material in dye-sensitized solar cells

  18. Flexible dye-sensitized solar cells with ZnO nanoparticles grown by Sonochemistry over Graphene/PET substrates.

    E-Print Network [OSTI]

    Pala, Nezih

    Flexible dye-sensitized solar cells with ZnO nanoparticles grown by Sonochemistry over Graphene and Engineering University of North Texas, Denton, Texas Flexible Dye sensitized solar cells (FDSSCs) are light characteristics of ZnO nanostructures over Graphene/PET as photoanode for flexible dye sensitized solar cells. #12;

  19. Simplifying strong electronic correlations in uranium: Localized uranium heavy-fermion UM2Zn20 (M=Co,Rh) compounds

    E-Print Network [OSTI]

    Lawrence, Jon

    Simplifying strong electronic correlations in uranium: Localized uranium heavy-fermion UM2Zn20 (M Atmica, 8400 Bariloche, Argentina 6 Department of Chemistry and Biochemistry, University of Delaware-field effects corroborate an ionic-like uranium electronic configura- tion in UM2Zn20. DOI: 10.1103/PhysRevB.78

  20. Catalysis Letters Vol. 77, No. 4, 2001 197 Effects of Zn, Cu, and K promoters on the structure

    E-Print Network [OSTI]

    Iglesia, Enrique

    and on the reduction, carburization, and catalytic behavior of iron-based FischerTropsch synthesis catalysts Senzi Li, and catalytic behavior of FeZn and Fe oxides used as precursors to FischerTropsch synthesis (FTS) catalystsZn oxide precursors. KEY WORDS: FischerTropsch synthesis; promoters; iron; carbide; copper; potassium

  1. Growth Mechanism and Electronic Structure of Zn3P2 on the Ga-Rich GaAs(001) Surface

    E-Print Network [OSTI]

    Atwater, Harry

    as well as the potential for low-cost, thin-film fabrication make Zn3P2 a promising active material Zn3P2 films on III-V substrates unlocks a promising pathway toward high-efficiency, earth-abundant photovoltaic devices fabricated on reusable, single-crystal templates. The detailed chemical, structural

  2. Study of Even-Even/Odd-Even/Odd-Odd Nuclei in Zn-Ga-Ge Region in the Proton-Neutron IBM/IBFM/IBFFM

    SciTech Connect (OSTI)

    Yoshida, N. [Faculty of Informatics, Kansai University, Takatsuki 569-1095 (Japan); Brant, S. [Department of Physics, Faculty of Science, University of Zagreb, 10000 Zagreb (Croatia); Zuffi, L. [Dipartimento di Fisica dell'Universita di Milano and Istituto Nazionale di Fisica Nucleare, Sezione di Milano, Via Celoria 16, Milano 20133 (Italy)

    2009-08-26T23:59:59.000Z

    We study the even-even, odd-even and odd-odd nuclei in the region including Zn-Ga-Ge in the proton-neutron IBM and the models derived from it: IBM2, IBFM2, IBFFM2. We describe {sup 67}Ga, {sup 65}Zn, and {sup 68}Ga by coupling odd particles to a boson core {sup 66}Zn. We also calculate the beta{sup +}-decay rates among {sup 68}Ge, {sup 68}Ga and {sup 68}Zn.

  3. Strain effects and band parameters in MgO, ZnO, and CdO Qimin Yan, Patrick Rinke, Momme Winkelnkemper, Abdallah Qteish, Dieter Bimberg et al.

    E-Print Network [OSTI]

    parameters) and strain deformation potentials for MgO, ZnO, and CdO in the wurtzite phase. To overcome family have the same equilib- rium crystal structure. While ZnO crystalizes in the wurtzite phase, MgO and CdO adopt the rocksalt phase. In spite of this complication wurtzite Zn1?xMgxO and Zn1?xCdxO alloys

  4. ZnO Nanorod Thermoplastic Polyurethane Nanocomposites: Morphology and Shape Memory Performance

    SciTech Connect (OSTI)

    Koerner, H.; Kelley, J; George, J; Drummy, L; Mirau, P; Bell, N; Hsu, J; Vaia, R

    2009-01-01T23:59:59.000Z

    The impact of dispersed alkylthiol-modified ZnO nanorods, as a function of rod aspect ratio and concentration, on the shape memory character of a thermoplastic polyurethane with low hard-segment density (LHS-TPU) is examined relative to the enhanced performance occurring for carbon nanofiber (CNF) dispersion. Solution blending resulted in uniform dispersion within the LHS-TPU of the ZnO nanorods at low volume (weight) fractions (<2.9% v/v (17.75% w/w)). Tensile modulus enhancements were modest though, comparable to values observed for spherical nanofillers. Shape memory characteristics, which in this LHS-TPU result when strain-induced crystallites retard the entropic recovery of the deformed chains, were unchanged for these low volume fraction ZnO nanocomposites. Higher ZnO loadings (12% v/v (50% w/w)) exhibited clustering of ZnO nanorods into a mesh-like structure. Here, tensile modulus and shape recovery characteristics were improved, although not as great as seen for comparable CNF addition. Wide angle X-ray diffraction and NMR revealed that the addition of ZnO nanorods did not impact the inherent strain induced crystallization of the LHS-TPU, which is in contrast to the impact of CNFs and emphasizes the impact of interactions at the polymer-nanoparticle interface. Overall, these findings reinforce the hypothesis that the shape memory properties of polymer nanocomposites are governed by the extent to which nanoparticle addition, via nanoparticle aspect ratio, hierarchical morphology, and interfacial interactions, impacts the molecular mechanism responsible for trapping elastic strain.

  5. Electronics System for the GammaTracker Handheld CdZnTe Detector

    SciTech Connect (OSTI)

    Myjak, Mitchell J.; Morris, Scott J.; Slaugh, Ryan W.; McCann, Jason M.; Kirihara, Leslie J.; Rohrer, John S.; Burghard, Brion J.; Seifert, Carolyn E.

    2007-12-31T23:59:59.000Z

    We are currently developing a handheld radioisotope identifier containing eighteen position-sensitive CdZnTe crystals. In addition to isotope identification, the device performs basic Compton imaging to determine the location of suspected sources. This paper gives an overview of the electronics system we have designed for this instrument. We use specialized application-specific integrated circuits to preprocess the outputs of each CdZnTe crystal. A low-power microprocessor running Windows CE drives the user interface and implements the isotope identification and directionality computations. Finally, we use a field-programmable gate array to perform the computationally intensive imaging tasks in real time.

  6. Double beta decay of ^{64,70}Zn and ^{180,186}W isotopes

    E-Print Network [OSTI]

    D. V. Poda

    2011-12-05T23:59:59.000Z

    The results of the experimental investigations of double beta processes in Zinc and Tungsten isotopes with the help of middle volume (117 g, 168 g and 699 g) low-background ZnWO_4 crystal scintillators are presented. The experiment was carried out in the low-background "DAMA/R&D" set-up at the Gran Sasso National Laboratories of the INFN (Italy) at a depth of \\approx3600 m w.e. The total measurement time exceeds ten thousand hours. New improved half-life limits on double electron capture and electron capture with positron emission in ^{64}Zn have been set: T^{2\

  7. ZnTe:O phosphor development for x-ray imaging applications

    SciTech Connect (OSTI)

    Kang, Z.T.; Summers, C.J.; Menkara, H.; Wagner, B.K.; Durst, R.; Diawara, Y.; Mednikova, G.; Thorson, T. [Phosphor Technology Center of Excellence, School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0245 (United States); Georgia Tech Research Institute, Georgia Institute of Technology, Atlanta, Georgia 30332-0826 (United States); Bruker AXS 5465 East Cheryl Parkway, Madison Wisconson 53711 (United States)

    2006-03-13T23:59:59.000Z

    An efficient ZnTe:O x-ray powder phosphor was prepared by a dry synthesis process using gaseous doping and etching medias. The x-ray luminescent properties were evaluated and compared to standard commercial phosphors exhibited an x-ray luminescent efficiency equivalent to 76% of Gd{sub 2}O{sub 2}S:Tb and an equal resolution of 2.5 lines/mm. In addition, the fast decay time, low afterglow, and superior spectral match to conventional charge-coupled devices-indicate that ZnTe:O is a very promising phosphor candidate for x-ray imaging applications.

  8. Preparation and characterization of nanodiamond cores coated with a thin Ni-Zn-P alloy film

    SciTech Connect (OSTI)

    Wang Rui; Ye Weichun; Ma Chuanli [College of Chemistry and Chemical Engineering, Lanzhou University, 730000 Lanzhou (China); Wang Chunming [College of Chemistry and Chemical Engineering, Lanzhou University, 730000 Lanzhou (China)], E-mail: wangcm@lzu.edu.cn

    2008-02-15T23:59:59.000Z

    Nanodiamond cores coated with a thin Ni-Zn-P alloy film were prepared by an electroless deposition method under the conditions of tin chloride sensitization and palladium chloride activation. The prepared materials were analyzed by Fourier transform infrared (FTIR) spectrometry and X-ray diffraction (XRD). The nanostructure of the materials was then characterized by transmission electron microscopy (TEM). The alloy film composition was characterized by Energy Dispersive X-ray (EDX) analysis. The results indicated the approximate composition 49.84%Ni-37.29%Zn-12.88%P was obtained.

  9. Laser Treatment of Ag@ZnO Nanorods as Long Life Span SERS Surfaces

    E-Print Network [OSTI]

    Macias-Montero, Manuel; J. Pelez, Ramn; Rico, Victor J.; Saghi, Zineb; Midgley, Paul; Afonso, Carmen N.; Gonzlez-Elipe, Agustn R.; Borras, Ana

    2015-01-09T23:59:59.000Z

    on semiconductor nanorods or nanowires of Si, Ge or ZnO, have led to significant enhancements in Raman scattering. 18,19 These evidences have prompted the study of composites or heterostructures formed by semiconductors and noble metals to promote higher SERS... of Surface-Enhanced Raman Scattering in ZnO Nanocrystals. J. Raman Spectrosc., 2009, 40, 1072-1077. 18 Li, X. H.; Chen, G. Y.; Yang, L. B.; Jin Z.; Liu, J. H. Multifunctional Au-Coated TiO2 Nanotube Arrays as Recyclable SERS Substrates for Multifold...

  10. Laser Treatment of Ag@ZnO Nanorods as Long-Life-Span SERS Surfaces

    E-Print Network [OSTI]

    Macias-Montero, Manuel; Pelez, Ramn J.; Rico, Victor J.; Saghi, Zineb; Midgley, Paul; Afonso, Carmen N.; Gonzlez-Elipe, Agustn R.; Borras, Ana

    2015-01-09T23:59:59.000Z

    on semiconductor nanorods or nanowires of Si, Ge or ZnO, have led to significant enhancements in Raman scattering. 18,19 These evidences have prompted the study of composites or heterostructures formed by semiconductors and noble metals to promote higher SERS... of Surface-Enhanced Raman Scattering in ZnO Nanocrystals. J. Raman Spectrosc., 2009, 40, 1072-1077. 18 Li, X. H.; Chen, G. Y.; Yang, L. B.; Jin Z.; Liu, J. H. Multifunctional Au-Coated TiO2 Nanotube Arrays as Recyclable SERS Substrates for Multifold...

  11. Impurity Diffusion Coefficients of Al and Zn in Mg Determined from Solid-to-Solid Diffusion Couples

    SciTech Connect (OSTI)

    Kammerer, Catherine [University of Central Florida, Orlando; Kulkarni, Nagraj S [ORNL; Warmack, Robert J Bruce [ORNL; Perry, Kelly A [ORNL; Belova, Irina [University of Newcastle, NSW, Australia; Murch, Prof. Graeme [University of Newcastle, NSW, Australia; Sohn, Yong Ho [University of Central Florida

    2013-08-01T23:59:59.000Z

    Increasing use and development of lightweight Mgalloys have led to the desire for more fundamental research in and understanding of Mg-based systems. As property enhancing components, Al and Zn are two of the most important and common alloying elements for Mg-alloys. We have investigated the concentration dependent interdiffusion of Al and Zn in Mg using diffusion couples of pure polycrystalline Mg mated to Mg solid solutions containing either <9 at.% Al or <3 at.% Zn. Concentration profiles were determined by electron micro-probe microanalysis of the diffusion zone. The interdiffusion coefficients were determined by the classical Boltzmann-Matano method within the Mg solid solution. As the concentration of Al or Zn approaches the dilute ends, we employ an analytical approach based on the Hall method to estimate the impurity diffusion coefficients. Results of Al and Zn impurity diffusion in Mg are reported and compared to published impurity diffusion coefficients typically determined by thin film techniques.

  12. Engineering of optical polarization based on electronic band structures of A-plane ZnO layers under biaxial strains

    SciTech Connect (OSTI)

    Matsui, Hiroaki, E-mail: hiroaki@ee.t.u-tokyo.ac.jp; Tabata, Hitoshi [Department of Bioengineering, The University of Tokyo, 1-3-7 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Department of Electrical Engineering and Information Systems, The University of Tokyo, 1-3-7 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Hasuike, Noriyuki; Harima, Hiroshi [Department of Electronics and Information Science, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan)

    2014-09-21T23:59:59.000Z

    In-plane anisotropic strains in A-plane layers on the electronic band structure of ZnO were investigated from the viewpoint of optical polarization anisotropy. Investigations utilizing kp perturbation theory revealed that energy transitions and associated oscillation strengths were dependent on in-plane strains. The theoretical correlation between optical polarizations and in-plane strains was experimentally demonstrated using A-plane ZnO layers with different in-plane strains. Finally, optical polarization anisotropy and its implications for in-plane optical properties are discussed in relation to the energy shift between two orthogonal directions. Higher polarization rotations were obtained in an A-plane ZnO layer with in-plane biaxially compressive strains as compared to strain-free ZnO. This study provides detailed information concerning the role played by in-plane strains in optically polarized applications based on nonpolar ZnO in the ultra-violet region.

  13. Structure and stability of NH complexes in single-crystal ZnO S. J. Jokela and M. D. McCluskeya

    E-Print Network [OSTI]

    McCluskey, Matthew

    Received 20 March 2010; accepted 4 May 2010; published online 11 June 2010 Zinc oxide ZnO is semiconductor.1063/1.3443457 I. INTRODUCTION The renewed interest in zinc oxide ZnO has continued to grow over the last decade conductor.2 ZnO is already prevalent in industry, in devices such as solar cells3 and varistors.4 Research

  14. Role of copper in the regulation of CU, ZN-superoxide dismutase in human K562 erythroleukemia cells and human fibroblasts

    E-Print Network [OSTI]

    Yu, Dan

    1994-01-01T23:59:59.000Z

    Activation of the enzyme CU2Zn2-SUperoxide dismutase (CuZnSOD) by its copper cofactor was studied in K562 erythroleukemia cells and skin fibroblasts. K562 cells were incubated in medium supplemented with 0-50 IIM CUC12 or ZnCI2 for 24 h and extracts...

  15. Effects of Dye Loading Conditions on the Energy Conversion Efficiency of ZnO and TiO2 Dye-Sensitized Solar Cells

    E-Print Network [OSTI]

    Cao, Guozhong

    light conversion efficiency of zinc oxide (ZnO) film electrodes in dye-sensitized solar cellsO) has been explored as an alternative material in dye-sensitized solar cells. The use of Zn as an alternative material for improving the solar cell performance in dye-sensitized solar cells due to (1) Zn

  16. Core-shell multi-quantum wells in ZnO / ZnMgO nanowires with high optical efficiency at room temperature

    E-Print Network [OSTI]

    Thierry, Robin; Jouneau, Pierre-Henri; Ferret, Pierre; Feuillet, Guy; 10.1088/0957-4484/23/8/085705

    2013-01-01T23:59:59.000Z

    Nanowire-based light-emitting devices require multi-quantum well heterostructures with high room temperature optical efficiencies. We demonstrate that such efficiencies can be attained through the use of ZnO/Zn(1-x)MgxO core shell quantum well heterostructures grown by metal organic vapour phase epitaxy. Varying the barrier Mg concentration from x=0.15 to x=0.3 leads to the formation of misfit induced dislocations in the multi quantum wells. Correlatively, temperature dependant photoluminescence reveals that the radial well luminescence intensity decreases much less rapidly with increasing temperature for the lower Mg concentration. Indeed, about 54% of the 10K intensity is retained at room temperature with x=0.15, against 2% with x=0.30. Those results open the way to the realization of high optical efficiency nanowire-based light emitting diodes.

  17. Proton Dynamics in ZnO Nanorods Quantified by In Situ Solid-State 1H Nuclear Magnetic Resonance

    SciTech Connect (OSTI)

    Wang, Li Q.; Zhou, Xiao Dong; Exarhos, Gregory J.; Pederson, Larry R.; Wang, Chong M.; Windisch, Charles F.; Yao, Chunhua

    2007-10-22T23:59:59.000Z

    Zinc oxide (ZnO) adopts wurtzite structure and possesses a direct wide band gap (Eg ~ 3.3 eV at 300 K), similar to that of GaN (Eg ~ 3.4 eV at 300 K), which enables ZnO as an alternative candidate to replace GaN for use in optoelectronic devices. The present controversy is centered at the microscopic origin of the native donors, particularly after ab initio calculations by Van de Walle, which indicate that hydrogen is soluble in ZnO at the interstitial sites, effectively forming a donor level just below the conduction band in ZnO. Hence, the origin of n type conductivity in ZnO is proposed due to the presence of hydrogen. Electron paramagnetic resonance and spectroscopic observations of muons provide experimental evidence of hydrogen presence in ZnO. Whereas, Look et al. suggests that the complex of zinc interstitial and nitrogen defect is a stronger candidate for donor than hydrogen interstitials under N ambient. Hydrogen-oxygen complex is claimed to be stable even at T > 1000C in the hydrothermally synthesized ZnO. Therefore, the thermodynamic nature of hydrogen characteristics remains controversial, particularly its role on resident defects. In this letter, in situ temperature dependent solid state 1H magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy is employed to probe the local chemical environments of hydrogen in ZnO nanorods. To best knowledge of ours, this is the first time that the presence of hydrogen, its concentration, and local transport dynamics are directly chemically determined. Moreover, in situ NMR allows a new approach to investigate the absorption and desorption of protons from different sites on the ZnO nanorods, thus study of site-specific proton dynamics in ZnO becomes feasible.

  18. Factors Affecting Ni and Zn Hydroxide Precipitate Formation in Soils. (S02-peltier222185-oral)

    E-Print Network [OSTI]

    Sparks, Donald L.

    Factors Affecting Ni and Zn Hydroxide Precipitate Formation in Soils. (S02-peltier222185-oral) Authors: E.F. Peltier* - Univ. of Delaware D.L. Sparks - Univ. of Delaware Abstract: The formation matter in the soil. Speaker Information: Edward Peltier, Univ. of Delaware, Dept. of Plant and Soil

  19. Double Direct Templating of Periodically Nanostructured ZnS Hollow Microspheres

    E-Print Network [OSTI]

    Braun, Paul

    Double Direct Templating of Periodically Nanostructured ZnS Hollow Microspheres Alejandro Wolosiuk 61801 Received July 22, 2005; E-mail: pbraun@uiuc.edu Hollow capsules are both technologically and scientifically interesting. "Smart" nano- and microcontainers could lead new catalysts, structures

  20. Carriers-mediated ferromagnetic enhancement in Al-doped ZnMnO dilute magnetic semiconductors

    SciTech Connect (OSTI)

    Saleem, Murtaza [Centre of Excellence in Solid State Physics, University of the Punjab, Lahore-54590 (Pakistan); Siddiqi, Saadat A. [Centre of Excellence in Solid State Physics, University of the Punjab, Lahore-54590 (Pakistan); Interdisciplinary Research Centre in Biomedical Materials (IRCBM), COMSATS Institute of Information Technology, Defence Road, Off Raiwind Road, Lahore (Pakistan); Atiq, Shahid, E-mail: shahidatiqpasrur@yahoo.com [Centre of Excellence in Solid State Physics, University of the Punjab, Lahore-54590 (Pakistan); Anwar, M. Sabieh; Hussain, Irshad [School of Science and Engineering (SSE), Lahore University of Management Sciences (LUMS), Opposite Sector U, D.H.A. Lahore Cantt-54792 (Pakistan); Alam, Shahzad [Pakistan Council for Scientific and Industrial Research (PCSIR) Laboratories Complex, Lahore (Pakistan)

    2011-11-15T23:59:59.000Z

    Nano-crystalline Zn{sub 0.95-x}Mn{sub 0.05}Al{sub x}O (x = 0, 0.05, 0.10) dilute magnetic semiconductors (DMS) were synthesized by sol-gel derived auto-combustion. X-ray diffraction (XRD) analysis shows that the samples have pure wurtzite structure typical of ZnO without the formation of secondary phases or impurity. Crystallite sizes were approximated by Scherrer formula while surface morphology and grain sizes were measured by field emission scanning electron microscopy. Incorporation of Mn and Al into the ZnO structure was confirmed by energy-dispersive X-ray analysis. Temperature dependent electrical resistivity measurements showed a decreasing trend with the doping of Al in ZnMnO, which is attributable to the enhancement of free carriers. Vibrating sample magnetometer studies confirmed the presence of ferromagnetic behavior at room temperature. The results indicate that Al doping results in significant variation in the concentration of free carriers and correspondingly the carrier-mediated magnetization and room temperature ferromagnetic behavior, showing promise for practical applications. We attribute the enhanced saturation magnetization and electrical conductivity to the exchange interaction mediated by free electrons.

  1. Cu2ZnSnS4 nanocrystals and graphene quantum dots for photovoltaics Xukai Xinab

    E-Print Network [OSTI]

    Lin, Zhiqun

    Cu2ZnSnS4 nanocrystals and graphene quantum dots for photovoltaics Jun Wang,a Xukai Xinab advances in the synthesis and utilization of CZTS nanocrystals and colloidal GQDs for photovoltaics emerged to achieve low cost, high perfor- mance photovoltaics, including organic solar cells,26 dye

  2. Growth of vertically aligned ZnO nanowalls for inverted polymer solar cells

    E-Print Network [OSTI]

    Cao, Guozhong

    Growth of vertically aligned ZnO nanowalls for inverted polymer solar cells Zhiqiang Liang a,n a School of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001, PR China b May 2013 Keywords: Inverted polymer solar cells Zinc oxide Nanowalls Aqueous solution growth a b s t r

  3. Crystallographic Orientation-Aligned ZnO Nanorods Grown by a Tin Catalyst

    E-Print Network [OSTI]

    Wang, Zhong L.

    a horizontal tube furnace, a rotary pump system, and a gas supply system. A mixture of commercial ZnO, SnO2 and positioned at the center of the alumina tube. To investigate the duration time dependence on the growth a constant pressure of 200 mbar and an Ar flow rate of 20 sccm (standard cubic centimeters per minute

  4. MOCVD growth mechanisms of ZnO nanorods G Perillat-Merceroz1, 2

    E-Print Network [OSTI]

    Boyer, Edmond

    cells, gas sensors or LEDs. Their high crystalline quality and purity, due to growth without a catalyst, are adequate for optoelectronic applications. MOCVD growth [2] enables fast, large area deposition details ZnO nanorods were grown using catalyst-free MOCVD in a horizontal hot-wall Epigress reactor. The c

  5. Trap and recombination centers study in sprayed Cu?ZnSnS? thin films

    SciTech Connect (OSTI)

    Courel, Maykel, E-mail: maykelcourel@gmail.com; Vigil-Galn, O.; Jimnez-Olarte, D. [Escuela Superior de Fsica y Matemticas-Instituto Politcnico Nacional (IPN), C.P. 07738, Mxico DF (Mexico); Espndola-Rodrguez, M. [Escuela Superior de Fsica y Matemticas-Instituto Politcnico Nacional (IPN), C.P. 07738, Mxico DF (Mexico); Catalonia Institute for Energy Research (IREC), Jardins de les Dones de Negre 1, 08930 Sant Adri de Bess, Barcelona (Spain); Saucedo, E. [Catalonia Institute for Energy Research (IREC), Jardins de les Dones de Negre 1, 08930 Sant Adri de Bess, Barcelona (Spain)

    2014-10-07T23:59:59.000Z

    In this work, a study of trap and recombination center properties in polycrystalline Cu?ZnSnS? thin films is carried out in order to understand the poor performance in Cu?ZnSnS? thin film solar cells. Thermally stimulated current has been studied in Cu?ZnSnS? deposited by pneumatic spray pyrolysis method using various heating rates, in order to gain information about trap centers and/or deep levels present within the band-gap of this material. A set of temperature-dependent current curves revealed three levels with activation energy of 12610, 47625, and 1100100 meV. The possible nature of the three levels found is presented, in which the first one is likely to be related to Cu{sub Zn} antisites, while second and third to Sn vacancies and Sn{sub Cu} antisites, respectively. The values of frequency factor, capture cross section, and trap concentration have been determined for each center.

  6. Phase controlled synthesis of ZnS nanobelts: zinc blende vs wurtzite Yong Ding a

    E-Print Network [OSTI]

    Wang, Zhong L.

    Phase controlled synthesis of ZnS nanobelts: zinc blende vs wurtzite Yong Ding a , Xu Dong WangS nanostructures normally take the metastable wurtzite structure. This Letter investigates the conditions under which the formed phase can be con- trolled between zinc blende and wurtzite in nanomaterials synthesis

  7. Mn-Substituted Inorganic-Organic Hybrid Materials Based on ZnSe

    E-Print Network [OSTI]

    Li, Jing

    for optoelectronics and information storage technology. In this study, we demonstrate that the hybrid nanostructuresMn-Substituted Inorganic-Organic Hybrid Materials Based on ZnSe: Nanostructures That May Lead are highly desirable and extremely attractive in the development of new multifunctional devices

  8. Energy level alignment of polythiophene/ZnO hybrid solar cells

    E-Print Network [OSTI]

    Garfunkel, Eric

    Energy level alignment of polythiophene/ZnO hybrid solar cells W. Feng,a S. Rangan,b Y. Cao,c E between energy level alignment and photovoltaic properties of a model bilayer hybrid solar cell. Galoppini,c R. A. Bartynskib and E. Garfunkel*ab Energy level alignment at interfaces is critical

  9. Modelling the Zn emissions from roofing materials at Crteil city scale -Defining a methodology

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    Modelling the Zn emissions from roofing materials at Crteil city scale - Defining a methodology@cereve.enpc.fr) Abstract Today, urban runoff is considered as an important source of environment pollution. Roofing. An accurate evaluation of contaminant flows from roofs is thus required at the city scale. This paper aims

  10. Fabrication of stable, wide-bandgap thin films of Mg, Zn and O

    DOE Patents [OSTI]

    Katiyar, Ram S.; Bhattacharya, Pijush; Das, Rasmi R.

    2006-07-25T23:59:59.000Z

    A stable, wide-bandgap (approximately 6 eV) ZnO/MgO multilayer thin film is fabricated using pulsed-laser deposition on c-plane Al2O3 substrates. Layers of ZnO alternate with layers of MgO. The thickness of MgO is a constant of approximately 1 nm; the thicknesses of ZnO layers vary from approximately 0.75 to 2.5 nm. Abrupt structural transitions from hexagonal to cubic phase follow a decrease in the thickness of ZnO sublayers within this range. The band gap of the thin films is also influenced by the crystalline structure of multilayer stacks. Thin films with hexagonal and cubic structure have band-gap values of 3.5 and 6 eV, respectively. In the hexagonal phase, Mg content of the films is approximately 40%; in the cubic phase Mg content is approximately 60%. The thin films are stable and their structural and optical properties are unaffected by annealing at 750.degree. C.

  11. ZnO nanoparticles and nanowire array hybrid photoanodes for dye-sensitized solar cells

    E-Print Network [OSTI]

    Cao, Guozhong

    ZnO nanoparticles and nanowire array hybrid photoanodes for dye-sensitized solar cells Supan for dye-sensitized solar cell DSC with NW arrays to serve as a direct pathway for fast electron transport Institute of Physics. doi:10.1063/1.3327339 Dye-sensitized solar cells DSCs have attracted a lot

  12. Sonochemically grown ZnO nanowalls on Graphene layers as Photoanode in Dye sensitized Solar cells.

    E-Print Network [OSTI]

    Pala, Nezih

    Sonochemically grown ZnO nanowalls on Graphene layers as Photoanode in Dye sensitized Solar cells whole solar spectrum Graphene can be a very promising material in Dye Sensitized Solar cells (DSSC as photoanode is presented. The effect of Graphene on dye loading and on efficiency of DSSC is quantitatively

  13. Formation of single crystalline ZnO nanotubes without catalysts and templates

    E-Print Network [OSTI]

    Geohegan, David B.

    to accomplish the uses of other ZnO nanostructures for ap- plications at the cutting edge of nanoscale is a numerical factor which depends on the site of the deposition, a is the lattice spacing, and q is the charge, according to sequence since 6 5 1 4 2 3.18 Thus an atomically flat layer will always spread from the edges

  14. Fabrication of ZnO nanorod using spray-pyrolysis and chemical bath deposition method

    SciTech Connect (OSTI)

    Ramadhani, Muhammad F., E-mail: brian@tf.itb.ac.id; Pasaribu, Maruli A. H., E-mail: brian@tf.itb.ac.id; Yuliarto, Brian, E-mail: brian@tf.itb.ac.id; Nugraha, E-mail: brian@tf.itb.ac.id [Advanced Functional Materials Laboratory, Engineering Physics Department Faculty of Industrial Technology, Institut Teknologi Bandung (Indonesia)

    2014-02-24T23:59:59.000Z

    ZnO thin films with nanorod structure were deposited using Ultrasonic Spray Pyrolysis method for seed growth, and Chemical Bath Deposition (CBD) for nanorod growth. High purity Zn-hydrate and Urea are used to control Ph were dissolved in ethanol and aqua bidest in Ultrasonic Spray Pyrolysis process. Glass substrate was placed above the heater plate of reaction chamber, and subsequently sprayed with the range duration of 5, 10 and 20 minutes at the temperatures of 3500 C. As for the Chemical Bath Deposition, the glass substrate with ZnO seed on the surface was immerse to Zn-hydrate, HMTA (Hexa Methylene Tetra Amine) and deionized water solution for duration of 3, 5 and 7 hour and temperatures of 600 C, washed in distilled water, dried, and annealed at 3500 C for an hour. The characterization of samples was carried out to reveal the surface morphology using Scanning Electron Microscopy (SEM). From the data, the combination of 5 minutes of Ultrasonic Spray Pyrolysis process and 3 hour of CBD has showed the best structure of nanorod. Meanwhile the longer Spraying process and CBD yield the bigger nanorod structure that have been made, and it makes the films more dense which make the nanorod collide each other and as a result produce unsymetric nanorod structure.

  15. Microstructured porous ZnO thin film for increased light scattering and improved

    E-Print Network [OSTI]

    Demir, Hilmi Volkan

    for enhancing light scattering and efficiency in inverted organic photovoltaics. High degree of porosity. References and links 1. S. R. Forrest, "The limits to organic photovoltaic cell efficiency," MRS Bull. 30Microstructured porous ZnO thin film for increased light scattering and improved efficiency

  16. Chitosan and chitosanZnO-based complex nanoparticles: formation, characterization, and

    E-Print Network [OSTI]

    Frenkel, Anatoly

    , i.e. the antimicrobial activity of chitosan. Moreover, hybrid nanoorganometallic particles were properties and superior inhibition of bacterial growth have been observed for porous CSsilver nanocomposite of color and UV-blocking properties.16 Reports for preparing ZnOCS nanocomposites are based

  17. Properties of GaN and ZnO Quantum Dots

    E-Print Network [OSTI]

    CHAPTER 3 Properties of GaN and ZnO Quantum Dots Vladimir A. Fonoberov, Alexander A. Balandin Nano. GaN Quantum Dots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 2.1. Electron and Hole States in Strained Wurtzite and Zincblende GaN Quantum Dots

  18. Terahertz dielectric properties of high-resistivity single-crystal ZnO Abul K. Azad

    E-Print Network [OSTI]

    experimentally that ZnO shows significantly higher radiation hardness than Si, GaN, and GaAs.5 Additionally absorption, and dielectric function are well fit by the pseudo-harmonic model of dielectric response. In addition, from the extrapolation of the experimental results, we show that the absorption is dominated

  19. Optical and structural properties of homoepitaxial ZnO T. P. Bartela

    E-Print Network [OSTI]

    Nabben, Reinhard

    , ZnO was grown in heteroepitaxy on different substrates such as Sapphire and GaN where it suffers from with particular focus on the polarity of the surface of the substrate. Photoluminescence spectra exhibit strong dependence of the bound exciton recombinations on the termination of the substrate. This is particularly

  20. HIGH PRESSURE VAPOR TRANSPORT OF ZnGeP 2 : II. THREEDIMENSIONAL SIMULATION OF GASDYNAMICS UNDER

    E-Print Network [OSTI]

    the laser damage threshold of ZnGeP 2 non­linear optical devices that are built with bulk single crystals in HPVT crystal growth. Introduction Non­linear optical interactions in birefringent materials find laser) radiation. Typically, these materials have been processed using bulk crystal growth techniques

  1. Hydrothermal Synthesis and Structural Characterization of Novel Zn-Triazole-Benzenedicarboxylate Frameworks

    SciTech Connect (OSTI)

    Park, Hyunsoo; Moureau, David M.; Parise, John B. (SBU)

    2008-10-03T23:59:59.000Z

    Three new metal-organic coordination polymers were synthesized hydrothermally using Zn2+ ion, 1,2,4-triazole, and 1,4-benzenedicarboxylic acid (BDC): Zn5(H2O)2(C2H2N3)4(C8H4O4)3 {center_dot} 3.9H2O (1), Zn2(C2H2N3)2(C2H3N3)(C8H4O4) {center_dot} 2.5H2O (2), and Zn4(H2O)2(C2H2N3)4(C8H4O4)2 {center_dot} 14H2O (3). Their crystal structures were determined by single-crystal X-ray diffraction. Their thermal properties were examined by thermogravimetric analysis. Structure 1 crystallizes in the monoclinic P21/n space group with a = 10.192(2) {angstrom}, b = 17.764(4) {angstrom}, c = 24.437(5) {angstrom}, {beta} = 91.19(3){sup o}, and V = 4423.3(15) {angstrom}3. Structure 2 crystallizes in the triclinic P space group with a = 7.797(2) {angstrom}, b = 10.047(2) {angstrom}, c = 13.577(3) {angstrom}, {alpha} = 110.18(3){sup o}, {beta} = 105.46(3){sup o}, {gamma} = 93.90(3){sup o}, and V = 947.0(3) {angstrom}3. Structure 3 crystallizes in monoclinic P21/n space group with a = 13.475(3) {angstrom}, b = 26.949(5) {angstrom}, c = 13.509(3) {angstrom}, {beta} = 95.18(3){sup o}, and V = 4885.7(17) {angstrom}3. In structure 1, the units of the triazole-Zn polyhedra are linked by BDC in a zigzag fashion to create the stacking of phenyl groups along the a axis. In structure 2, both triazole and BDC bridge Zn polyhedra in the (011) plane, resulting in the eight-membered channels along the a axis. In the case of structure 3, the BDC links the Zn polyhedra along the b axis to form a pillared open framework. This structure is the most porous of the compounds presented in this work.

  2. Single-step in-situ synthesis and optical properties of ZnSe nanostructured dielectric nanocomposites

    SciTech Connect (OSTI)

    Dey, Chirantan; Rahaman Molla, Atiar; Tarafder, Anal; Karmakar, Basudeb, E-mail: basudebk@cgcri.res.in [CSIR-Central Glass and Ceramic Research Institute, Glass Science and Technology Section, Glass Division, 196, Raja S. C. Mullick Road, 700032 Kolkata (India); Kr Mishra, Manish; De, Goutam [CSIR-Central Glass and Ceramic Research Institute, Nano-Structured Materials Division, 196, Raja S. C. Mullick Road, 700032 Kolkata (India); Goswami, Madhumita; Kothiyal, G. P. [Glass and Advanced Ceramics Division, Bhaba Atomic Research Centre, Trombay, 400085 Mumbai (India)

    2014-04-07T23:59:59.000Z

    This work provides the evidence of visible red photoluminescent light emission from ZnSe nanocrystals (NCs) grown within a dielectric (borosilicate glass) matrix synthesized by a single step in-situ technique for the first time and the NC sizes were controlled by varying only the concentration of ZnSe in glass matrix. The ZnSe NCs were investigated by UV-Vis optical absorption spectroscopy, Raman spectroscopy, and transmission electron microscopy (TEM). The sizes of the ZnSe NCs estimated from the TEM images are found to alter in the range of 253?nm. Their smaller sizes of the NCs were also calculated by using the optical absorption spectra and the effective mass approximation model. The band gap enlargements both for carrier and exciton confinements were evaluated and found to be changed in the range of 01.0?eV. The Raman spectroscopic studies showed blue shifted Raman peaks of ZnSe at 295 and 315?cm{sup ?1} indicating phonon confinement effect as well as compressive stress effect on the surface atoms of the NCs. Red photoluminescence in ZnSe-glass nanocomposite reveals a broad multiple-peak structure due to overlapping of emission from NC size related electron-hole recombination (?707?nm) and emissions from defects to traps, which were formed due to Se and Zn vacancies signifying potential application in photonics.

  3. Essential role of catalysts (Mn, Au, and Sn) in the vapor liquid solid growth kinematics of ZnS nanowires

    SciTech Connect (OSTI)

    Rehman, S.; Shehzad, M. A.; Hafeez, M.; Bhatti, A. S., E-mail: asbhatti@comsats.edu.pk [Center for Micro and Nano Devices (CMND), Department of Physics, COMSATS Institute of Information Technology, Islamabad 44000 (Pakistan)

    2014-01-14T23:59:59.000Z

    In this paper, we demonstrate that surface energy of the catalyst is a vital parameter for the growth rate, self doping of the self assembled nanowires synthesized by employing vapor liquid solid growth technique. The synthesis of ZnS nanowires was done by selectively using three different catalysts (Mn, Au, and Sn), where Au, is the most common catalyst, was used as a reference. The distinctive difference in the growth rate was due to the surface energy of the metal alloy droplet and the interface energies, as explained theoretically using thermodynamic approach. We have found that the activation energy of diffusion of (Zn, S) species in the catalyst droplet was low in Sn (0.41?eV for Zn and 0.13?eV for S) and high in Mn (1.79?eV for Zn and 0.61?eV for S) compared to Au (0.62?eV for Zn and 0.21?eV for S) catalyzed ZnS nanostructures. The thermodynamic calculations predicted the growth rates of Sn (7.5?nm/s) catalyzed nanowires was faster than Au (5.1?nm/s) and Mn (4.6?nm/s) catalyzed ZnS nanostructures, which were in agreement with the experimental results. Finally, the location of the catalyst as dopant in the grown nanostructure was predicted and compared with experimental observations.

  4. Synthesis and optical study of green light emitting polymer coated CdSe/ZnSe core/shell nanocrystals

    SciTech Connect (OSTI)

    Tripathi, S.K., E-mail: surya@pu.ac.in [Department of Physics, Center of Advanced Study in Physics, Panjab University, Chandigarh 160 014 (India); Sharma, Mamta [Department of Physics, Center of Advanced Study in Physics, Panjab University, Chandigarh 160 014 (India)

    2013-05-15T23:59:59.000Z

    Highlights: ? Synthesis of Polymer coated core CdSe and CdSe/ZnSe core/shell NCs. ? From TEM image, the spherical nature of CdSe and CdSe/ZnSe is obtained. ? Exhibiting green band photoemission peak at 541 nm and 549 nm for CdSe core and CdSe/ZnSe core/shell NCs. ? The shell thickness has been calculated by using superposition of quantum confinement energy model. - Abstract: CdSe/ZnSe Core/Shell NCs dispersed in PVA are synthesized by chemical method at room temperature. This is characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV/Vis spectra and photoluminescence spectroscopy (PL). TEM image shows the spherical nature of CdSe/ZnSe core/shell NCs. The red shift of absorption and emission peak of CdSe/ZnSe core/shell NCs as compared to CdSe core confirmed the formation of core/shell. The superposition of quantum confinement energy model is used for calculation of thickness of ZnSe shell.

  5. Zn-Doping Dependence of Stripe Order in La1.905Ba0.095CuO4

    SciTech Connect (OSTI)

    Hucker, M.; Zimmermann, M.v.; Xu, Z.J.; Wen, J.S.; Gu, G.D.; Tian, W.; Zarestky, J.; Tranquada, J.M.

    2011-04-01T23:59:59.000Z

    The effect of Zn-doping on the stripe order in La{sub 1.905}Ba{sub 0.095}CuO{sub 4} has been studied by means of x-ray and neutron diffraction as well as magnetization measurements. While 1% Zn leads to an increase of the spin stripe order, it unexpectedly causes a wipe out of the visibility of the charge stripe order. A magnetic field of 10 Tesla applied along the c-axis has no reversing effect on the charge order. We compare this observation with the Zn-doping dependence of the crystal structure, superconductivity, and normal state magnetism.

  6. Electrodeposition and room temperature ferromagnetic anisotropy of Co and Ni-doped ZnO nanowire arrays

    SciTech Connect (OSTI)

    Cui, J.B.; Gibson, U.J. [Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755-8000 (United States)

    2005-09-26T23:59:59.000Z

    Cobalt and nickel doped ZnO nanowire arrays were synthesized by an electrochemical process at a temperature of 90 deg. C. Energy dispersive x-ray spectroscopy and x-ray diffraction show that the dopants are incorporated into the wurtzite-structure ZnO. Anisotropic ferromagnetism with an easy direction of magnetization either perpendicular or parallel to the wire axis, depending on the wire geometry and density, was observed in 1.7% Co and 2.2% Ni-doped ZnO nanowires at room temperature. The anisotropic magnetism was explained in terms of a competition between self-demagnetization and magnetostatic coupling among the nanowires.

  7. Magnetic field induced third order susceptibility of third order harmonic generation in a ZnMgSe strained quantum well

    SciTech Connect (OSTI)

    Mark, J. Abraham Hudson, E-mail: a.john.peter@gmail.com; Peter, A. John, E-mail: a.john.peter@gmail.com [Dept. of Physics, SSM Institute of Engineering and Technology, Dindigul-624002 (India)

    2014-04-24T23:59:59.000Z

    Third order susceptibility of third order harmonic generation is investigated in a Zn{sub 0.1}Mg{sub 0.9}Se/Zn{sub 0.8}Mg{sub 0.2}Se/Zn{sub 0.1}Mg{sub 0.9}Se quantum well in the presence of magnetic field strength. The confinement potential is considered as the addition of energy offsets of the conduction band (or valence band) and the strain-induced potential in our calculations. The material dependent effective mass is followed throughout the computation because it has a high influence on the electron energy levels in low dimensional semiconductor systems.

  8. Carrier dynamics in bulk ZnO. I. Intrinsic conductivity measured by terahertz time-domain spectroscopy

    E-Print Network [OSTI]

    at room temperature.3 Thin films of ZnO are useful in transparent transistors and transparent conducting coatings because of their combination of wide band gap, high conductivity, and processability.4

  9. Origin of ultraviolet photoluminescence in ZnO quantum dots: Confined excitons versus surface-bound impurity exciton complexes

    E-Print Network [OSTI]

    Fonoberov, Vladimir

    sources of PL. © 2004 American Institute of Physics. [DOI: 10.1063/1.1835992] Zinc oxide (ZnO) has diodes, laser diodes, varistors, and transparent con- ducting films. Compared to other wide band

  10. ZnO light-emitting diode grown by plasma-assisted metal organic chemical vapor deposition

    SciTech Connect (OSTI)

    Xu, W.Z.; Ye, Z.Z.; Zeng, Y.J.; Zhu, L.P.; Zhao, B.H.; Jiang, L.; Lu, J.G.; He, H.P.; Zhang, S.B. [State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027 (China); National Renewable Energy Laboratory, Golden, Colorado 80401 (United States)

    2006-04-24T23:59:59.000Z

    We report a breakthrough in fabricating ZnO homojunction light-emitting diode by metal organic chemical vapor deposition. Using NO plasma, we are able to grow p-type ZnO thin films on n-type bulk ZnO substrates. The as-grown films on glass substrates show hole concentration of 10{sup 16}-10{sup 17} cm{sup -3} and mobility of 1-10 cm{sup 2} V{sup -1} s{sup -1}. Room-temperature photoluminescence spectra reveal nitrogen-related emissions. A typical ZnO homojunction shows rectifying behavior with a turn-on voltage of about 2.3 V. Electroluminescence at room temperature has been demonstrated with band-to-band emission at I=40 mA and defect-related emissions in the blue-yellow spectrum range.

  11. Fast Response and High Sensitivity ZnO/glass Surface Acoustic Wave Humidity Sensors Using Graphene Oxide Sensing Layer

    E-Print Network [OSTI]

    Xuan, Weipeng; He, Mei; Meng, Nan; He, Xingli; Wang, Wenbo; Chen, Jinkai; Shi, Tianjin; Hasan, Tawfique; Xu, Zhen; Xu, Yang; Luo, J. K.

    2014-11-26T23:59:59.000Z

    We report ZnO/glass surface acoustic wave (SAW) humidity sensors with high sensitivity and fast response using graphene oxide sensing layer. The frequency shift of the sensors is exponentially correlated to the humidity change, induced mainly...

  12. Band structure engineering for solar energy applications: ZnO1-xSex films and devices

    E-Print Network [OSTI]

    Mayer, Marie Annette

    2012-01-01T23:59:59.000Z

    W. Walukiewicz, and J. Wu, Solar Energy Materials and Solarand M. J. Carter, Solar Energy Materials and Solar Cells 51,structure engineering for solar energy applications: ZnO 1-x

  13. Electronic structure of Al- and Ga-doped ZnO films studied by hard X-ray photoelectron spectroscopy

    SciTech Connect (OSTI)

    Gabs, M.; Ramos Barrado, Jos R. [Lab. de Materiales and Superficies, Dpto. de Fsica Aplicada I, Universidad de Mlaga, 29071 Mlaga (Spain); Torelli, P. [Laboratorio TASC, IOM-CNR, S.S. 14 km 163.5, Basovizza, I-34149 Trieste (Italy); Barrett, N. T. [CEA, DSM/IRAMIS/SPCSI, F-91191 Gif-sur-Yvette Cedex (France); Sacchi, M. [Synchrotron SOLEIL, BP 48, 91192 Gif-sur-Yvette, France and Institut des NanoSciences de Paris, UPMC Paris 06, CNRS UMR 7588, 4 Place Jussieu, 75005 Paris (France)

    2014-01-01T23:59:59.000Z

    Al- and Ga-doped sputtered ZnO films (AZO, GZO) are semiconducting and metallic, respectively, despite the same electronic valence structure of the dopants. Using hard X-ray photoelectron spectroscopy we observe that both dopants induce a band in the electronic structure near the Fermi level, accompanied by a narrowing of the Zn 3d/O 2p gap in the valence band and, in the case of GZO, a substantial shift in the Zn 3d. Ga occupies substitutional sites, whereas Al dopants are in both substitutional and interstitial sites. The latter could induce O and Zn defects, which act as acceptors explaining the semiconducting character of AZO and the lack of variation in the optical gap. By contrast, mainly substitutional doping is consistent with the metallic-like behavior of GZO.

  14. Synthesis, characterization, and photocatalytic properties of ZnO/(La,Sr)CoO3 composite nanorod arrays

    E-Print Network [OSTI]

    Alpay, S. Pamir

    of photocatalyst candidates for organic molecule degradation. Introduction Ultrahigh surface area and unique or ZnO can be used in photo- catalysis and photovoltaic cells with high efficiencies.810 Because

  15. Localization of Competing Metals (Ni, Co, and Zn) in Alyssum using micro-XRF and Tomography. (3564)

    E-Print Network [OSTI]

    Sparks, Donald L.

    Localization of Competing Metals (Ni, Co, and Zn) in Alyssum using micro-XRF and Tomography. (3564 and observed metal localization in root and shoot tissue using synchrotron based micro-XRF and tomography

  16. Use of separate ZnTe interface layers to form ohmic contacts to p-CdTe films

    DOE Patents [OSTI]

    Gessert, T.A.

    1999-06-01T23:59:59.000Z

    A method of is disclosed improving electrical contact to a thin film of a p-type tellurium-containing II-VI semiconductor comprising: depositing a first undoped layer of ZnTe on a thin film of p-type tellurium containing II-VI semiconductor with material properties selected to limit the formation of potential barriers at the interface between the p-CdTe and the undoped layer, to a thickness sufficient to control diffusion of the metallic-doped ZnTe into the p-type tellurium-containing II-VI semiconductor, but thin enough to minimize affects of series resistance; depositing a second heavy doped p-type ZnTe layer to the first layer using an appropriate dopant; and depositing an appropriate metal onto the outer-most surface of the doped ZnTe layer for connecting an external electrical conductor to an ohmic contact. 11 figs.

  17. High-performance zero-bias ultraviolet photodetector based on p-GaN/n-ZnO heterojunction

    SciTech Connect (OSTI)

    Su, Longxing; Zhang, Quanlin; Chen, Mingming; Su, Yuquan; Zhu, Yuan; Xiang, Rong; Gui, Xuchun [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Wu, Tianzhun, E-mail: tz.wu@siat.ac.cn [Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055 (China); Tang, Zikang, E-mail: phzktang@ust.hk [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (China)

    2014-08-18T23:59:59.000Z

    Lattice-match p-GaN and n-ZnO bilayers were heteroepitaxially grown on the c-sapphire substrate by metal organic chemical vapor deposition and molecular beam epitaxy technique, respectively. X-ray diffraction and photoluminescence investigations revealed the high crystal quality of the bilayer films. Subsequently, a p-GaN/n-ZnO heterojunction photodetector was fabricated. The p-n junction exhibited a clear rectifying I-V characteristic with a turn-on voltage of 3.7?V. At zero-bias voltage, the peak responsivity was 0.68?mA/W at 358?nm, which is one of the best performances reported for p-GaN/n-ZnO heterojunction detectors due to the excellent crystal quality of the bilayer films. These show that the high-performance p-GaN/n-ZnO heterojunction diode is potential for applications of portable UV detectors without driving power.

  18. Prolactin receptor attenuation induces zinc pool redistribution through ZnT2 and decreases invasion in MDA-MB-453 breast cancer cells

    SciTech Connect (OSTI)

    Bostanci, Zeynep, E-mail: zbostanci@hmc.psu.edu [The Pennsylvania State University, Department of Nutritional Sciences, 209 Chandlee Lab, University Park, PA 16802 (United States); The Pennsylvania State University Milton S. Hershey Medical Center, Department of Surgery, 500 University Dr., Hershey, PA 17033 (United States); Alam, Samina, E-mail: sra116@psu.edu [The Pennsylvania State University, Department of Nutritional Sciences, 209 Chandlee Lab, University Park, PA 16802 (United States); The Pennsylvania State University Milton S. Hershey Medical Center, Department of Surgery, 500 University Dr., Hershey, PA 17033 (United States); Soybel, David I., E-mail: dsoybel@hmc.psu.edu [The Pennsylvania State University, Department of Nutritional Sciences, 209 Chandlee Lab, University Park, PA 16802 (United States); The Pennsylvania State University Milton S. Hershey Medical Center, Department of Surgery, 500 University Dr., Hershey, PA 17033 (United States); The Pennsylvania State University College of Medicine, Department of Cell and Molecular Physiology, 500 University Dr., Hershey, PA 17033 (United States); Kelleher, Shannon L., E-mail: slk39@psu.edu [The Pennsylvania State University, Department of Nutritional Sciences, 209 Chandlee Lab, University Park, PA 16802 (United States); The Pennsylvania State University Milton S. Hershey Medical Center, Department of Surgery, 500 University Dr., Hershey, PA 17033 (United States); The Pennsylvania State University College of Medicine, Department of Cell and Molecular Physiology, 500 University Dr., Hershey, PA 17033 (United States)

    2014-02-15T23:59:59.000Z

    Prolactin receptor (PRL-R) activation regulates cell differentiation, proliferation, cell survival and motility of breast cells. Prolactin (PRL) and PRL-R over-expression are strongly implicated in breast cancer, particularly contributing to tumor growth and invasion in the more aggressive estrogen-receptor negative (ER?) disease. PRL-R antagonists have been suggested as potential therapeutic agents; however, mechanisms through which PRL-R antagonists exert their actions are not well-understood. Zinc (Zn) is a regulatory factor for over 10% of the proteome, regulating critical cell processes such as proliferation, cell signaling, transcription, apoptosis and autophagy. PRL-R signaling regulates Zn metabolism in breast cells. Herein we determined effects of PRL-R attenuation on cellular Zn metabolism and cell function in a model of ER-, PRL-R over-expressing breast cancer cells (MDA-MB-453). PRL-R attenuation post-transcriptionally increased ZnT2 abundance and redistributed intracellular Zn pools into lysosomes and mitochondria. ZnT2-mediated lysosomal Zn sequestration was associated with reduced matrix metalloproteinase 2 (MMP-2) activity and decreased invasion. ZnT2-mediated Zn accumulation in mitochondria was associated with increased mitochondrial oxidation. Our results suggest that PRL-R antagonism in PRL-R over-expressing breast cancer cells may reduce invasion through the redistribution of intracellular Zn pools critical for cellular function. - Highlights: PRL-R attenuation increased ZnT2 expression. PRL-R attenuation increased lysosomal and mitochondrial Zn accumulation. PRL-R attenuation decreased MMP-2 and invasion. PRL-R antagonists may modulate lysosomal and mitochondrial Zn pools.

  19. Blueshift of optical band gap in ZnO thin films grown by metal-organic chemical-vapor deposition

    E-Print Network [OSTI]

    . INTRODUCTION Zinc oxide ZnO is a wide direct band-gap 3.37 eV semiconductor with a broad range of applications. Dimethylzinc DMZn , N2 gas, and high-purity O2 were used as the zinc source, carrier gas, and oxidizing agent including light-emitting devices,1 varistors,2 solar cells,3 and gas sensors.4 Moreover, ZnO is a promising

  20. Charge carrier and spin doping in ZnO thin films D.P. Norton a,*, M. Ivill a

    E-Print Network [OSTI]

    Hebard, Arthur F.

    in the hexagonal (wurtzite) crystal structure shown in Fig. 1, with a =3.25 A° and c =5.12 A° . Each Zn atom to approximately 4.0 eV while still maintaining the wurtzite structure. The latter represents a metastable compound that is stabilized via epitaxial film growth. Epitaxial wurtzite Zn1?xMgxO thin films have been realized with x

  1. Structural study and phase transition investigation in a simple synthesis of porous architected-ZnO nanopowder

    SciTech Connect (OSTI)

    Shang, C.; Barnab, A., E-mail: barnabe@chimie.ups-tlse.fr

    2013-12-15T23:59:59.000Z

    In this work, zinc oxide powder with a rectangular-shaped porous architecture, made of numerous spherical nanometric particles, was obtained. A simple precipitation/decomposition procedure was used comprising a zinc oxalate intermediate, obtained from zinc sulfate and oxalic acid without any additives. Detailed studies on zinc oxalate dehydration, decomposition and zinc oxide formation, were carried out using in-situ temperature X-ray diffraction and thermogravimetric analysis. During the investigation, the temperature dependence of particle sizes, lattice parameters and crystal structures of ZnC{sub 2}O{sub 4}2H{sub 2}O, ZnC{sub 2}O{sub 4} and ZnO nanopowders were analyzed from room temperature to 450 C. Structural transitions were also discussed. The structure and morphology of the as-prepared ZnO nanopowder were investigated by electron microscopy and compared to the crystalline rectangular shape of ZnC{sub 2}O{sub 4}2H{sub 2}O. The calcination temperature, counter ion and precipitate agent were found to be related to the product's shape and diameter. Spherical ZnO nanoparticles with diameters of less than 20 nm and a maximum specific surface of 53 m{sup 2}/g were obtained using this method. Highlights: ZnO nanopowders with porous architecture were synthesized by a simple method. Spherical ZnO nanoparticles confined in submicronic rectangular shape are obtained. Crystal structures are determined temperature in-situ XRD up to 450 C. Structural transitions were analyzed.

  2. Spectral photoresponse of ZnSe/GaAs(001) heterostructures with CdSe ultra-thin quantum well insertions

    SciTech Connect (OSTI)

    Valverde-Chvez, D. A.; Sutara, F.; Hernndez-Caldern, I. [Physics Department, Cinvestav-IPN, Av. IPN 2508, 07360 Mxico, DF (Mexico)

    2014-05-15T23:59:59.000Z

    We present a study of the spectral photoresponse (SPR) of ZnSe/GaAs(001) heterostructures for different ZnSe film thickness with and without CdSe ultra-thin quantum well (UTQW) insertions. We observe a significant increase of the SPR of heterostructures containing 3 monolayer thick CdSe UTQW insertions; these results encourage their use in photodetectors and solar cells.

  3. Effect of temperature and time on properties of Spark Plasma Sintered NiCuZn: Co ferrite

    E-Print Network [OSTI]

    Effect of temperature and time on properties of Spark Plasma Sintered NiCuZn: Co ferrite K. Zehani hundred MHz, and a high resistivity, but the conventional sintering temperature is too high for co. EXPERIMENTAL: Powders of basic oxides Fe2O3, NiO, CuO and ZnO and Co2O3 were used for the preparation of Ni

  4. Optically optimal wavelength-scale patterned ITO/ZnO composite coatings for thin film solar cells

    E-Print Network [OSTI]

    Moreau, Antoine; Centeno, Emmanuel; Seassal, Christian

    2012-01-01T23:59:59.000Z

    A new methodology is proposed for finding structures that are, optically speaking, locally optimal : a physical analysis of much simpler structures is used to constrain the optimization process. The obtained designs are based on a flat amorphous silicon layer (to minimize recombination) with a patterned anti-reflective coating made of ITO or ZnO, or a composite ITO/ZnO coating. These latter structures are realistic and present good performances despite very thin active layers.

  5. Optical Properties of Wurtzite GaN and ZnO Quantum Dots Vladimir A. Fonoberov and Alexander A. Balandin

    E-Print Network [OSTI]

    Fonoberov, Vladimir

    Optical Properties of Wurtzite GaN and ZnO Quantum Dots Vladimir A. Fonoberov and Alexander A-Riverside, Riverside, California 92521, U.S.A. ABSTRACT We have investigated exciton states in wurtzite GaN/AlN and ZnO quantum dots. A strong piezoelectric field in GaN/AlN quantum dots is found to tilt conduction and valence

  6. Comparison of strong coupling regimes in bulk GaAs, GaN and ZnO semiconductor microcavities

    E-Print Network [OSTI]

    Boyer, Edmond

    , transmission and absorption spectra of bulk GaAs, GaN and ZnO microcavities, in order to compareComparison of strong coupling regimes in bulk GaAs, GaN and ZnO semiconductor microcavities SAs and GaN microcavities. PACS numbers: 78.67.-n, 71.36.+c, 78.20.Ci, 78.55.Cr, 78.55.Et Keywords: polariton

  7. Changes induced in a ZnS:Cr-based electroluminescent waveguide structure by intrinsic near-infrared laser radiation

    SciTech Connect (OSTI)

    Vlasenko, N. A., E-mail: vlasenko@isp.kiev.ua; Oleksenko, P. F.; Mukhlyo, M. A.; Veligura, L. I. [National Academy of Sciences of Ukraine, Lashkarev Institute of Semiconductor Physics (Ukraine)] [National Academy of Sciences of Ukraine, Lashkarev Institute of Semiconductor Physics (Ukraine)

    2013-08-15T23:59:59.000Z

    The causes of changes that occur in a thin-film electroluminescent metal-insulator-semiconductor-insulator-metal waveguide structure based on ZnS:Cr (Cr concentration of {approx}4 Multiplication-Sign 10{sup 20} cm{sup -3}) upon lasing ({lambda} Almost-Equal-To 2.6 {mu}m) and that induce lasing cessation are studied. It is established that lasing ceases because of light-scattering inhomogeneities formed in the structure and, hence, optical losses enhance. The origin of the inhomogeneities and the causes of their formation are clarified by studying the surface topology and the crystal structure of constituent layers of the samples before and after lasing. The studies are performed by means of atomic force microscopy and X-ray radiography. It is shown that a substantial increase in the sizes of grains on the surface of the structure is the manifestation of changes induced in the ZnS:Cr film by recrystallization. Recrystallization is initiated by local heating by absorbed laser radiation in existing Cr clusters and quickened by a strong electric field (>1 MV cm{sup -1}). The changes observed in the ZnS:Cr film are as follows: the textured growth of ZnS crystallites, an increase in the content of Cr clusters, and the appearance of some CrS and a rather high ZnO content. Some ways for improving the stability of lasing in the ZnS:Cr-based waveguide structures are proposed.

  8. Photovoltaic effect in an indium-tin-oxide/ZnO/BiFeO{sub 3}/Pt heterostructure

    SciTech Connect (OSTI)

    Fan, Zhen [Department of Materials Science and Engineering, National University of Singapore (Singapore); Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology, and Research) (Singapore); Yao, Kui, E-mail: k-yao@imre.a-star.edu.sg, E-mail: msewangj@nus.edu.sg [Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology, and Research) (Singapore); Wang, John, E-mail: k-yao@imre.a-star.edu.sg, E-mail: msewangj@nus.edu.sg [Department of Materials Science and Engineering, National University of Singapore (Singapore)

    2014-10-20T23:59:59.000Z

    We have studied the photovoltaic effect in a metal/semiconductor/ferroelectric/metal heterostructure of In{sub 2}O{sub 3}-SnO{sub 2}/ZnO/BiFeO{sub 3}/Pt (ITO/ZnO/BFO/Pt) multilayer thin films. The heterolayered structure shows a short-circuit current density (J{sub sc}) of 340??A/cm{sup 2} and an energy conversion efficiency of up to 0.33% under blue monochromatic illumination. The photovoltaic mechanism, specifically in terms of the major generation site of photo-excited electron-hole (e-h) pairs and the driving forces for the separation of e-h pairs, is clarified. The significant increase in photocurrent of the ITO/ZnO/BFO/Pt compared to that of ITO/BFO/Pt is attributed to the abundant e-h pairs generated from ZnO. Ultraviolet photoelectron spectroscopy reveals the energy band alignment of ITO/ZnO/BFO/Pt, where a Schottky barrier and an n{sup +}-n junction are formed at the BFO/Pt and ZnO/BFO interfaces, respectively. Therefore, two built-in fields developed at the two interfaces are constructively responsible for the separation and transport of photo-excited e-h pairs.

  9. A comparative study of physico-chemical properties of CBD and SILAR grown ZnO thin films

    SciTech Connect (OSTI)

    Jambure, S.B.; Patil, S.J.; Deshpande, A.R.; Lokhande, C.D., E-mail: l_chandrakant@yahoo.com

    2014-01-01T23:59:59.000Z

    Graphical abstract: Schematic model indicating ZnO nanorods by CBD (Z{sub 1}) and nanograins by SILAR (Z{sub 2}). - Highlights: Simple methods for the synthesis of ZnO thin films. Comparative study of physico-chemical properties of ZnO thin films prepared by CBD and SILAR methods. CBD outperforms SILAR method. - Abstract: In the present work, nanocrystalline zinc oxide (ZnO) thin films have been successfully deposited onto glass substrates by simple and economical chemical bath deposition (CBD) and successive ionic layer adsorption reaction (SILAR) methods. These films were further characterized for their structural, optical, surface morphological and wettability properties. The X-ray diffraction (XRD) patterns for both CBD and SILAR deposited ZnO thin films reveal the highly crystalline hexagonal wurtzite structure. From optical studies, band gaps obtained are 2.9 and 3.0 eV for CBD and SILAR deposited thin films, respectively. The scanning electron microscope (SEM) patterns show growth of well defined randomly oriented nanorods and nanograins on the CBD and SILAR deposited samples, respectively. The resistivity of CBD deposited films (10{sup 2} ? cm) is lower than that of SILAR deposited films (10{sup 5} ? cm). Surface wettability studies show hydrophobic nature for both films. From the above results it can be concluded that CBD grown ZnO thin films show better properties as compared to SILAR method.

  10. Anisotropic hot deformed magnets prepared from Zn-coated MRE-Fe-B ribbon powder (MRE?=?Nd?+?Y?+?Dy)

    SciTech Connect (OSTI)

    Tang, W.; Zhou, L.; Sun, K. W.; Dennis, K. W.; Kramer, M. J.; Anderson, I. E.; McCallum, R. W.

    2014-05-07T23:59:59.000Z

    Milled melt-spun ribbon flake of MRE-Fe-B coated with Zn coating using a vapor transport technique was found to have significant increase in coercivity without degrading the magnetization when the Zn thickness and heat treatment were optimized. Magnetic measurements show that 0.51?wt.?% Zn coating increases the coercivity about 1?kOe over the initial ribbon powder. After vacuum hot deformation (VHD), the VHD magnet with Zn coating of 0.5?wt.?% results in a nearly 3?kOe higher coercivity than an un-coated alloy magnet. An optimized VHD magnet with 0.5?wt.?% Zn coating obtains a coercivity of 11.2?kOe and (BH)max of 23.0 MGOe, respectively. SEM and TEM microstructures analysis demonstrates that the Zn coating on the surface of ribbon powder has diffused along the intergranular boundaries after the ribbon powder was annealed at 750?C for 30?min or was hot deformed at 700750?C.

  11. Synthesis and characterization of Cr-doped ZnO nanorod-array photocatalysts with improved activity

    SciTech Connect (OSTI)

    Chang, Chi-Jung, E-mail: changcj@fcu.edu.tw; Yang, Tsung-Lin; Weng, Yu-Ching

    2014-06-01T23:59:59.000Z

    Immobilized photocatalysts with high catalytic activity under UV light were prepared by growing Cr-doped ZnO nanorods on glass substrates by a hydrothermal method. The effects of Cr dopant on the surface texture, crystallinity, surface chemistry, and photoinduced charge separation and their relation with the photocatalytic degradation of Cr-doped ZnO were investigated by scanning electron microscopy, diffuse reflectance spectra, photoelectrochemical scanning electrochemical microscopy, and X-ray photoemission spectroscopy. Adding the appropriate amount of Cr dopant is a powerful way to enhance the separation of charge carriers in ZnO photocatalyst. The photocatalytic activity was improved due to the increase in surface oxygen vacancies, the separation of charge carriers, modification of the band gap, and the large surface area of the doped ZnO nanorod photocatalyst. - Graphical abstract: Photoinduced charge separation and its relation with the photocatalytic degradation activity of Cr-doped ZnO were investigated by photoelectrochemical scanning electrochemical microscopy. - Highlights: Cr dopant enhances separation of charge carries in ZnO nanorod photocatalyst. Photoinduced charge carries separation monitored by PEC-SECM. The higher the photocurrent is, the higher the photocatalytic activity is. Degradation of DB86 dye solutions under visible light finished within 50 min. Higher activity due to more oxygen vacancy, tuned band gap and more surface area.

  12. High-performance solar-blind ultraviolet photodetector based on mixed-phase ZnMgO thin film

    SciTech Connect (OSTI)

    Fan, M. M. [Graduate University of the Chinese Academy of Sciences, Beijing 100049 (China); State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, No. 3888 Dongnanhu Road, 130033 Changchun (China); Liu, K. W., E-mail: liukw@ciomp.ac.cn, E-mail: shendz@ciomp.ac.cn; Zhang, Z. Z.; Li, B. H.; Chen, X.; Zhao, D. X.; Shan, C. X.; Shen, D. Z., E-mail: liukw@ciomp.ac.cn, E-mail: shendz@ciomp.ac.cn [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, No. 3888 Dongnanhu Road, 130033 Changchun (China)

    2014-07-07T23:59:59.000Z

    High Mg content mixed-phase Zn{sub 0.38}Mg{sub 0.62}O was deposited on a-face sapphire by plasma-assisted molecular beam epitaxy, based on which a metal-semiconductor-metal solar-blind ultraviolet (UV) photodetector was fabricated. The dark current is only 0.25?pA at 5?V, which is much lower than that of the reported mixed-phase ZnMgO photodetectors. More interestingly, different from the other mixed-phase ZnMgO photodetectors containing two photoresponse bands, this device shows only one response peak and its ?3?dB cut-off wavelength is around 275?nm. At 10?V, the peak responsivity is as high as 1.664?A/W at 260?nm, corresponding to an internal gain of ?8. The internal gain is mainly ascribed to the interface states at the grain boundaries acting as trapping centers of photogenerated holes. In view of the advantages of mixed-phase ZnMgO photodetectors over single-phase ZnMgO photodetectors, including easy fabrication, high responsivity, and low dark current, our findings are anticipated to pave a new way for the development of ZnMgO solar-blind UV photodetectors.

  13. Robust ferroelectric state in multiferroic Mn 1 ? x Zn x WO 4

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Chaudhury, R. P.; Ye, F.; Fernandez-Baca, J. A.; Lorenz, B.; Wang, Y. Q.; Sun, Y. Y.; Mook, H. A.; Chu, C. W.

    2011-01-01T23:59:59.000Z

    We report on the remarkably robust ferroelectric state in the multiferroic compound Mn1-xZnxWO?. Substitution of the magnetic Mn? with nonmagnetic Zn? reduces the magnetic exchange and provides control of the various magnetic and multiferroic states of MnWO?. Only 5% of Zn substitution results in complete suppression of the frustrated collinear (paraelectric) low-temperature phase. The helical magnetic and ferroelectric phase develops as the ground state. The multiferroic state is stable up to a high level of substitution of more than 50%. The magnetic, thermodynamic, and dielectric properties, as well as the ferroelectric polarization of single crystals of Mn1-xZnxWO?, are studied for different substitutions up to x=0.5. The magnetic phases have been identified in single-crystal neutron-scattering experiments. The ferroelectric polarization scales with the neutron intensity of the incommensurate peak of the helical phase.

  14. On quantitative analysis of interband recombination dynamics: Theory and application to bulk ZnO

    SciTech Connect (OSTI)

    Lettieri, S. [Institute for Superconductors, Oxides and Innovative Materials, National Research Council (CNR-SPIN), U.O.S. Napoli, Via Cintia, I-80126 Napoli (Italy)] [Institute for Superconductors, Oxides and Innovative Materials, National Research Council (CNR-SPIN), U.O.S. Napoli, Via Cintia, I-80126 Napoli (Italy); Capello, V.; Santamaria, L. [Physics Department, University of Naples Federico II, Via Cintia I-80126 Napoli (Italy)] [Physics Department, University of Naples Federico II, Via Cintia I-80126 Napoli (Italy); Maddalena, P. [Institute for Superconductors, Oxides and Innovative Materials, National Research Council (CNR-SPIN), U.O.S. Napoli, Via Cintia, I-80126 Napoli (Italy) [Institute for Superconductors, Oxides and Innovative Materials, National Research Council (CNR-SPIN), U.O.S. Napoli, Via Cintia, I-80126 Napoli (Italy); Physics Department, University of Naples Federico II, Via Cintia I-80126 Napoli (Italy)

    2013-12-09T23:59:59.000Z

    The issue of the quantitative analysis of time-resolved photoluminescence experiments is addressed by developing and describing two approaches for determination of unimolecular lifetime, bimolecular recombination coefficient, and equilibrium free-carrier concentration, based on a quite general second-order expression of the electron-hole recombination rate. Application to the case of band-edge emission of ZnO single crystals is reported, evidencing the signature of sub-nanosecond second-order recombination dynamics for optical transitions close to the interband excitation edge. The resulting findings are in good agreement with the model prediction and further confirm the presence, formerly evidenced in literature by non-optical methods, of near-surface conductive layers in ZnO crystals with sheet charge densities of about 3510{sup 13} cm{sup ?2}.

  15. ZnO buffer layer for metal films on silicon substrates

    DOE Patents [OSTI]

    Ihlefeld, Jon

    2014-09-16T23:59:59.000Z

    Dramatic improvements in metallization integrity and electroceramic thin film performance can be achieved by the use of the ZnO buffer layer to minimize interfacial energy between metallization and adhesion layers. In particular, the invention provides a substrate metallization method utilizing a ZnO adhesion layer that has a high work of adhesion, which in turn enables processing under thermal budgets typically reserved for more exotic ceramic, single-crystal, or metal foil substrates. Embodiments of the present invention can be used in a broad range of applications beyond ferroelectric capacitors, including microelectromechanical systems, micro-printed heaters and sensors, and electrochemical energy storage, where integrity of metallized silicon to high temperatures is necessary.

  16. Electrodeposition of corrosion-resistant Ni-Zn alloy. I. Cyclic voltammetric study

    SciTech Connect (OSTI)

    Lin, Yu-Po; Selman, J.R. (Illinois Inst. of Technology, Chicago (United States))

    1993-05-01T23:59:59.000Z

    The interaction between different reacting species involved in the initial stage of electrodeposition of nickel-zinc alloy was investigated. A cyclic voltammetric study indicates that codeposition of hydrogen and nickel occurs, with formation of two types of hydrogen-nickel solid solution, i.e., [beta]-Ni and [alpha]-Ni. This nickel hydride formation during Ni-Zn alloy electrodeposition was verified by analyzing the voltammograms of nickel, zinc, and Ni-Zn alloy during initial deposition on various substrates. The dissolution potential of zinc and nickel from electrodeposited nickel-zinc alloy spans a wide range (ca. 400 mV). The influence of the interaction between nickel, hydrogen, and zinc on the nucleation of nickel-zinc electrodeposition is reported in part II of this paper.

  17. Microstructural and optical studies on sonochemically synthesized Cu doped ZnO nanoparticles

    SciTech Connect (OSTI)

    Sahu, Dojalisa, E-mail: dojalisa.sahu@gmail.com; Panda, Nihar Ranjan, E-mail: dojalisa.sahu@gmail.com; Panda, A. K. [Sambalpur University, Jyoti Vihar, Burla -768019, Odisha (India); Acharya, B. S. [C.V. Raman College of Engineering, Bhubaneswar-752054, Odisha (India)

    2014-04-24T23:59:59.000Z

    Copper doped ZnO nanoparticles were synthesized by sonochemical method varying the concentration of the impurity. Systematic investigations like X-ray diffraction (XRD) and Transmission electron microscopy (TEM) were carried out to understand the microstructural properties. The average particle sizes and all the crystallographic parameters were calculated from XRD results. This shows the formation of wurtzite phase of ZnO with average size of the particles as 53 nm and an increase of particle size with dopant concentration was also been observed. UV absorption and Fourier transformed infrared spectroscopy (FTIR) spectra revealed the absorption at wavelength < 370 nm with a remarkable red shift of absorption band and a linear decrease of transmittance with increase in doping concentrations respectively.

  18. arvo ots toomas: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Perfluorocarboxylic acids 3 and their anhydrides 51can also be pyrolysed to lolm mixture of perfuoroalkencs. gen Cirkva, Vladimir 135 Product (a) Type (b) Weight Flag...

  19. arvo ots tnu: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Perfluorocarboxylic acids 3 and their anhydrides 51can also be pyrolysed to lolm mixture of perfuoroalkencs. gen Cirkva, Vladimir 137 Product (a) Type (b) Weight Flag...

  20. Supplementary Material Peter S. C. Wu and Gottfried Otting

    E-Print Network [OSTI]

    Otting, Gottfried

    DANTE pulses and disregarding radiation damping effects. The profile was calculated by selecting the z, respectively, in order to simulate the radiofrequency inhomogeneity. 75 Hz was the experimentally determined frequency distribution of the rf-field (Figure 1), the presence of radiation damping arising from steady

  1. akkumulyatorov ot solnechnoj: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    L2.9+-0.5x105 Lsun. Assuming spherical geometry, the black body effective radius, R2.0+-0.5x104 Rsun, and corresponding expansion velocity, v870+-260 kms, are remarkably...

  2. James L. Liveman, Acting AssLBtaOt

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilA group currentBradleyTableSelling CorpNewCF INDUSTRIES,L? .-I I2 m.m 2 1 ' ,1 - *

  3. New ZnO-Based Regenerable Sulfur Sorbents for Fluid-Bed/Transport Reactor Applications

    SciTech Connect (OSTI)

    Slimane, R.B.; Lau, F.S.; Abbasian, J.; Ho, K.H.

    2002-09-19T23:59:59.000Z

    The overall objective of the ongoing sorbent development work at GTI is the advancement to the demonstration stage of a promising ZnO-TiO2 sulfur sorbent that has been developed under DCCA/ICCI and DOE/NETL sponsorship. This regenerable sorbent has been shown to possess an exceptional combination of excellent chemical reactivity, high effective capacity for sulfur absorption, high resistance to attrition, and regenerability at temperatures lower than required by typical zinc titanates.

  4. Optically pumped quantum-dot Cd(Zn)Se/ZnSe laser and microchip converter for yellow-green spectral region

    SciTech Connect (OSTI)

    Lutsenko, E V; Voinilovich, A G; Rzheutskii, N V; Pavlovskii, V N; Yablonskii, G P; Sorokin, S V; Gronin, S V; Sedova, I V; Kop'ev, Petr S; Ivanov, Sergei V; Alanzi, M; Hamidalddin, A; Alyamani, A

    2013-05-31T23:59:59.000Z

    The room temperature laser generation in the yellow-green ({lambda} = 558.5-566.7 nm) spectral range has been demonstrated under optical pumping by a pulsed nitrogen laser of Cd(Zn)Se/ZnSe quantum dot heterostructures. The maximum achieved laser wavelength was as high as {lambda} = 566.7 nm at a laser cavity length of 945 {mu}m. High values of both the output pulsed power (up to 50 W) and the external differential quantum efficiency ({approx}60%) were obtained at a cavity length of 435 {mu}m. Both a high quality of the laser heterostructure and a low lasing threshold ({approx}2 kW cm{sup -2}) make it possible to use a pulsed InGaN laser diode as a pump source. A laser microchip converter based on this heterostructure has demonstrated a maximum output pulse power of {approx}90 mW at {lambda} = 560 nm. The microchip converter was placed in a standard TO-18 (5.6 mm in diameter) laser diode package. (semiconductor lasers. physics and technology)

  5. Unexpected magnetization enhancement in hydrogen plasma treated ferromagnetic (Zn,Cu)O film

    SciTech Connect (OSTI)

    Hu, Liang; Zhu, Liping, E-mail: zlp1@zju.edu.cn, E-mail: hphe@zju.edu.cn; He, Haiping, E-mail: zlp1@zju.edu.cn, E-mail: hphe@zju.edu.cn; Ye, Zhizhen [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China and Cyrus Tang Center for Sensor Materials and Applications, Zhejiang University, Hangzhou 310027 (China)

    2014-08-18T23:59:59.000Z

    The effects of H{sup +} incorporation on oxygen vacancies (H{sub O}{sup +}) on the giant ferromagnetic behavior (moment up to 3.26??{sub B}/Cu) in ZnO:Cu polycrystalline films have been closely examined using different microstructural and magnetic characterization tools. Fine thermal stability (up to 450?C) and low resistivity demonstrate a significant correlation between Cu 3d-states and H{sub O}{sup +} donor defects in H plasma treated ZnO:Cu films, analogous to dual-donor (V{sub O} and Zn{sub i}) defects mediated case. These H{sub O}{sup +} donors can delocalize their electrons to the orbits of Cu atoms and contribute to a stronger spin-orbit coupling interaction. Suitable H{sub O}{sup +} defect concentration and matched proportion between Cu{sup 2+} and Cu{sup +} species ensure that orbital momentum shall not be quenched. Hence, unexpected moment enhancement, less than spin-orbit coupling upper limit (3.55??{sub B}/Cu), can be also expected in this scenario. The manipulation from spin-only to spin-orbit coupling mode, using a facile thermally-mediated H plasma exposure way, will allow achieving spin transport based diluted magnetic semiconductor device.

  6. Oxidation of palladium on Au(111) and ZnO(0001) supports

    SciTech Connect (OSTI)

    Batzill, M. [Univ. of South Florida, Tampa, FL (United States); Sutter, P. [Brookhaven National Lab. (BNL), Upton, NY (United States); Lallo, J. [Univ. of South Florida, Tampa, FL (United States); Tenney, S. A. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2014-10-21T23:59:59.000Z

    The oxidation of supported Pd-deposits on Au(111) and ZnO(0001) single crystals has been studied by x- ray photoemission spectroscopy (XPS). Oxidation has been carried out ex-situ in a high-pressure cell with subsequent vacuum-transfer and characterization by XPS in ultrahigh vacuum (UHV), as well as using in-situ characterization by synchrotron based near-ambient pressure XPS. On Au(111) alloying of Pd with the substrate competes with oxidation and only sufficiently thick Pd films have been found to oxidize. For Pd on ZnO the oxidation conditions depend on the amount of deposited Pd. Thicker Pd deposits behave similar to bulk Pd, while thinner films oxidize already at lower temperatures. Interestingly, for very small amounts of Pd, in-situ XPS shows full oxidation at room temperature and at less than 0.6 mbar O? pressure. This indicates a lowering of the kinetic barriers for oxidation of very small supported Pd-clusters. The formed oxide is, however, not stable in UHV and a slow reduction is observed. The instability of this oxide indicates that the Pd-oxide formed at the interface to ZnO may have different chemical properties compared to bulk PdO or surface oxides on Pd.

  7. Determination of Zn, Pb, Cu, and Hg in soils of Ekpan, Nigeria

    SciTech Connect (OSTI)

    Omgbu, J.A.; Kokogho, M.A. (College of Education, Warri (Nigeria))

    1993-01-01T23:59:59.000Z

    The concentrations of zinc, lead, copper, and mercury in solids in Ekpan were determined in order to assess the impact of petroleum-refining activities. Twenty soil samples were collected 100 m apart (10 topsoils 0 to 15 cm and 10 bottom soils 15 to 30 cm). Sample solutions prepared were analyzed using the atomic absorption spectrophotometry technique. Results show that top-soil samples contain as much as 7.13 to 13.10 [mu]g/g Zn, 55.13 to 65.50 [mu]g/g Pb, 3.47 to 5.27 [mu]g/g Cu, and 4.00 to 6.50 [mu]g.g Hg. Bottom soil samples contain as much as 7.17 to 13.77 [mu]g/g Zn, 54.97 to 63.23 [mu]g/g Pb, 3.57 to 6.50 [mu]/g Cu, and 4.57 to 6.63 [mu]g/g Hg. The levels reported had an abundance ratio in the order Pb > Zn > Hg > Cu in the soil samples. It is recommended that appropriate measures be put in place by the companies to treat waste effluent before discharging them to the immediate environment. 8 refs., 2 tabs.

  8. Structural enhancement of ZnO on SiO{sub 2} for photonic applications

    SciTech Connect (OSTI)

    Ruth, Marcel; Meier, Cedrik [Experimental Physics, University of Paderborn, Paderborn (Germany)] [Experimental Physics, University of Paderborn, Paderborn (Germany)

    2013-07-15T23:59:59.000Z

    Multi-layer thin films are often the basis of photonic devices. Zinc oxide (ZnO) with its excellent optoelectronic properties can serve as a high quality emitter in structures like microdisks or photonic crystals. Here, we present a detailed study on the enhancement of the structural properties of low-temperature MBE grown ZnO on silica (SiO{sub 2}). By thermal annealing a grain coalescence of the initially polycrystalline layer leads to an enhancement of the electronic structure, indicated by a blue shift of the photoluminescence (PL) signal maximum. Oxygen atmosphere during the annealing process prevents the creation of intrinsic defects by out-diffusion. Pre-annealing deposited SiO{sub 2} capping layers instead obstruct the recrystallization and lead to less intense emission. While thin capping layers partially detach from the ZnO film at high temperatures and cause higher surface roughness and the weakest emission, thicker layers remain smoother and exhibit a significantly stronger photoluminescence.

  9. Gallium ion implantation greatly reduces thermal conductivity and enhances electronic one of ZnO nanowires

    SciTech Connect (OSTI)

    Xia, Minggang, E-mail: xiamg@mail.xjtu.edu.cn [Laboratory of Nanostructure and its Physics Properties, Department of Optical Information Science and Technology, Department of Applied Physics, and MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter, School of Science, Xi'an Jiaotong University, 710049 China (China); Department of Physics and Centre for Computational Science and Engineering, National University of Singapore, Singapore 117542 (Singapore); Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore); Cheng, Zhaofang; Han, Jinyun; Zhang, Shengli [Laboratory of Nanostructure and its Physics Properties, Department of Optical Information Science and Technology, Department of Applied Physics, and MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter, School of Science, Xi'an Jiaotong University, 710049 China (China); Zheng, Minrui [Department of Physics and Centre for Computational Science and Engineering, National University of Singapore, Singapore 117542 (Singapore); Sow, Chorng-Haur [Department of Physics and Centre for Computational Science and Engineering, National University of Singapore, Singapore 117542 (Singapore); National University of Singapore Nanoscience and Nanotechnology Initiative, National University of Singapore, Singapore 117542 (Singapore); Thong, John T. L. [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore); Li, Baowen [Department of Physics and Centre for Computational Science and Engineering, National University of Singapore, Singapore 117542 (Singapore); National University of Singapore Nanoscience and Nanotechnology Initiative, National University of Singapore, Singapore 117542 (Singapore); Center for Phononics and Thermal Energy Science, School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China)

    2014-05-15T23:59:59.000Z

    The electrical and thermal conductivities are measured for individual zinc oxide (ZnO) nanowires with and without gallium ion (Ga{sup +}) implantation at room temperature. Our results show that Ga{sup +} implantation enhances electrical conductivity by one order of magnitude from 1.01 10{sup 3} ?{sup ?1}m{sup ?1} to 1.46 10{sup 4} ?{sup ?1}m{sup ?1} and reduces its thermal conductivity by one order of magnitude from 12.7 Wm{sup ?1}K{sup ?1} to 1.22 Wm{sup ?1}K{sup ?1} for ZnO nanowires of 100 nm in diameter. The measured thermal conductivities are in good agreement with those in theoretical simulation. The increase of electrical conductivity origins in electron donor doping by Ga{sup +} implantation and the decrease of thermal conductivity is due to the longitudinal and transverse acoustic phonons scattering by Ga{sup +} point scattering. For pristine ZnO nanowires, the thermal conductivity decreases only two times when its diameter reduces from 100 nm to 46 nm. Therefore, Ga{sup +}-implantation may be a more effective method than diameter reduction in improving thermoelectric performance.

  10. Oxidation of palladium on Au(111) and ZnO(0001) supports

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Batzill, M.; Sutter, P.; Lallo, J.; Tenney, S. A.

    2014-10-21T23:59:59.000Z

    The oxidation of supported Pd-deposits on Au(111) and ZnO(0001) single crystals has been studied by x- ray photoemission spectroscopy (XPS). Oxidation has been carried out ex-situ in a high-pressure cell with subsequent vacuum-transfer and characterization by XPS in ultrahigh vacuum (UHV), as well as using in-situ characterization by synchrotron based near-ambient pressure XPS. On Au(111) alloying of Pd with the substrate competes with oxidation and only sufficiently thick Pd films have been found to oxidize. For Pd on ZnO the oxidation conditions depend on the amount of deposited Pd. Thicker Pd deposits behave similar to bulk Pd, while thinner filmsmoreoxidize already at lower temperatures. Interestingly, for very small amounts of Pd, in-situ XPS shows full oxidation at room temperature and at less than 0.6 mbar O? pressure. This indicates a lowering of the kinetic barriers for oxidation of very small supported Pd-clusters. The formed oxide is, however, not stable in UHV and a slow reduction is observed. The instability of this oxide indicates that the Pd-oxide formed at the interface to ZnO may have different chemical properties compared to bulk PdO or surface oxides on Pd.less

  11. Oxidation of palladium on Au(111) and ZnO(0001) supports

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Batzill, M. [Univ. of South Florida, Tampa, FL (United States); Sutter, P. [Brookhaven National Lab. (BNL), Upton, NY (United States); Lallo, J. [Univ. of South Florida, Tampa, FL (United States); Tenney, S. A. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2014-10-21T23:59:59.000Z

    The oxidation of supported Pd-deposits on Au(111) and ZnO(0001) single crystals has been studied by x- ray photoemission spectroscopy (XPS). Oxidation has been carried out ex-situ in a high-pressure cell with subsequent vacuum-transfer and characterization by XPS in ultrahigh vacuum (UHV), as well as using in-situ characterization by synchrotron based near-ambient pressure XPS. On Au(111) alloying of Pd with the substrate competes with oxidation and only sufficiently thick Pd films have been found to oxidize. For Pd on ZnO the oxidation conditions depend on the amount of deposited Pd. Thicker Pd deposits behave similar to bulk Pd, while thinner films oxidize already at lower temperatures. Interestingly, for very small amounts of Pd, in-situ XPS shows full oxidation at room temperature and at less than 0.6 mbar O? pressure. This indicates a lowering of the kinetic barriers for oxidation of very small supported Pd-clusters. The formed oxide is, however, not stable in UHV and a slow reduction is observed. The instability of this oxide indicates that the Pd-oxide formed at the interface to ZnO may have different chemical properties compared to bulk PdO or surface oxides on Pd.

  12. ZnMoO4: a promising bolometer for neutrinoless double beta decay searches

    E-Print Network [OSTI]

    J. W. Beeman; F. Bellini; S. Capelli; L. Cardani; N. Casali; I. Dafinei; S. Di Domizio; F. Ferroni; E. N. Galashov; L. Gironi; F. Orio; L. Pattavina; G. Pessina; G. Piperno; S. Pirro; V. N. Shlegel; Ya. V. Vasilyev; C. Tomei; M. Vignati

    2012-02-01T23:59:59.000Z

    We investigate the performances of two ZnMoO4 scintillating crystals operated as bolometers, in view of a next generation experiment to search the neutrinoless double beta decay of Mo-100. We present the results of the alpha vs beta/gamma discrimination, obtained through the scintillation light as well as through the study of the shape of the thermal signal alone. The discrimination capability obtained at the 2615 keV line of Tl-208 is 8 sigma, using the heat-light scatter plot, while it exceeds 20 sigma using the shape of the thermal pulse alone. The achieved FWHM energy resolution ranges from 2.4 keV (at 238 keV) to 5.7 keV (at 2615 keV). The internal radioactive contaminations of the ZnMoO4 crystals were evaluated through a 407 hours background measurement. The obtained limit is < 32 microBq/kg for Th-228 and Ra-226. These values were used for a Monte Carlo simulation aimed at evaluating the achievable background level of a possible, future array of enriched ZnMoO4 crystals.

  13. A violet emission in ZnS:Mn,Eu: Luminescence and applications for radiation detection

    SciTech Connect (OSTI)

    Ma, Lun; Chen, Wei, E-mail: weichen@uta.edu [Department of Physics and the SAVANT Center, The University of Texas at Arlington, Arlington, Texas 76019-0059 (United States); Jiang, Ke [Center for Biofrontiers Institute, University of Colorado at Colorado Springs, 1420 Austin Bluffs Pkwy., Colorado Springs, Colorado 80918 (United States); Liu, Xiao-tang [Department of Physics and the SAVANT Center, The University of Texas at Arlington, Arlington, Texas 76019-0059 (United States); Department of Applied Chemistry, College of Science, South China Agricultural University, Guangzhou 510642 (China)

    2014-03-14T23:59:59.000Z

    We prepared manganese and europium co-doped zinc sulfide (ZnS:Mn,Eu) phosphors and used them for radiation detection. In addition to the red fluorescence at 583?nm due to the d-d transition of Mn ions, an intense violet emission at 420?nm is newly observed in ZnS:Mn,Eu phosphors. The emission is related to Eu{sup 2+} doping but only appears at certain Eu{sup 2+} concentrations. It is found that the intensity of the 420?nm violet fluorescence is X-ray does-dependent, while the red fluorescence of 583?nm is not. The ratio of fluorescence intensities at 420?nm and 583?nm has been monitored as a function of X-ray doses that exposed upon the ZnS:Mn,Eu phosphors. Empirical formulas are provided to estimate the doses of applied X-ray irradiation. Finally, possible mechanisms of X-ray irradiation induced fluorescence quenching are discussed. The intense 420?nm emission not only provides a violet light for solid state lighting but also offers a very sensitive method for radiation detection.

  14. The new barium zinc mercurides Ba{sub 3}ZnHg{sub 10} and BaZn{sub 0.6}Hg{sub 3.4} - Synthesis, crystal and electronic structure

    SciTech Connect (OSTI)

    Schwarz, Michael; Wendorff, Marco [Institut fuer Anorganische und Analytische Chemie, University of Freiburg, Albertstr. 21, D-79104 Freiburg (Germany)] [Institut fuer Anorganische und Analytische Chemie, University of Freiburg, Albertstr. 21, D-79104 Freiburg (Germany); Roehr, Caroline, E-mail: caroline@ruby.chemie.uni-freiburg.de [Institut fuer Anorganische und Analytische Chemie, University of Freiburg, Albertstr. 21, D-79104 Freiburg (Germany)] [Institut fuer Anorganische und Analytische Chemie, University of Freiburg, Albertstr. 21, D-79104 Freiburg (Germany)

    2012-12-15T23:59:59.000Z

    The title compounds Ba{sub 3}ZnHg{sub 10} and BaZn{sub 0.6}Hg{sub 3.4} were synthesized from stoichiometric ratios of the elements in Ta crucibles. Their crystal structures, which both represent new structure types, have been determined using single crystal X-ray data. The structure of Ba{sub 3}ZnHg{sub 10} (orthorhombic, oP28, space group Pmmn, a=701.2(3), b=1706.9(8), c=627.3(3)pm, Z=2, R1=0.0657) contains folded 4{sup 4} Hg nets, where the meshes form the bases of flat rectangular pyramids resembling the structure of BaAl{sub 4}. The flat pyramids are connected via Hg-Zn/Hg bonds, leaving large channels at the folds, in which Ba(1) and Hg(2) atoms alternate. Whereas the remaining Hg/Zn atoms form a covalent 3D network of three- to five-bonded atoms with short M-M distances (273-301 pm; CN 9-11), the Hg(2) atoms in the channels adopt a comparatively large coordination number of 12 and increased distances (317-348 pm) to their Zn/Hg neighbours. In the structure of BaZn{sub 0.6}Hg{sub 3.4} (cubic, cI320, space group I4{sup Macron }3d, a=2025.50(7) pm, Z=64, R1=0.0440), with a chemical composition not much different from that of Ba{sub 3}ZnHg{sub 10}, the Zn/Hg atoms of the mixed positions M(1/2) are arranged in an slightly distorted primitive cubic lattice with a 4 Multiplication-Sign 4 Multiplication-Sign 4 subcell relation to the unit cell. The 24 of the originating 64 cubes contain planar cis tetramers Hg(5,6){sub 4} with Hg in a nearly trigonal planar or tetrahedral coordination. In another 24 of the small cubes, two opposing faces are decorated by Hg(3,4){sub 2} dumbbells, two by Ba(2) atoms respectively. The third type of small cubes are centered by Ba(1) atoms only. The complex 3D polyanionic Hg/Zn network thus formed is compared with the Hg partial structure in Rb{sub 3}Hg{sub 20} applying a group-subgroup relation. Despite their different overall structures, the connectivity of the negatively charged Hg atoms, the rather metallic Zn bonding characteristic (as obtained from FP-LAPW band structure calculations) and the coordination number of 16 for all Ba cations relate the two title compounds. - Graphical abstract: Six of the 64 small sub-cubes of three types (A, B, C) forming the unit cell of the Hg-rich mercuride BaZn{sub 0.6}Hg{sub 3.4}. Highlights: Black-Right-Pointing-Pointer Two new Hg-rich Ba mercurides, both synthesized from the elements in pure phase. Black-Right-Pointing-Pointer BaZn{sub 0.6}HgG{sub 3.4} and Ba{sub 3}ZnHg{sub 10} with new complex structure types. Black-Right-Pointing-Pointer Structure relation to other complex cubic intermetallics. Black-Right-Pointing-Pointer Discussion of covalent and metallic bonding aspects, as found by the structure features and band structure calculations.

  15. Real-structure effects: Band gaps of Mg_xZn_{1-x}O, Cd_xZn_{1-x}O, and n-type ZnO from ab-initio calculations

    SciTech Connect (OSTI)

    Schleife, A; Bechstedt, F

    2012-02-15T23:59:59.000Z

    Many-body perturbation theory is applied to compute the quasiparticle electronic structures and the optical-absorption spectra (including excitonic effects) for several transparent conducting oxides. We discuss HSE+G{sub 0}W{sub 0} results for band structures, fundamental band gaps, and effective electron masses of MgO, ZnO, CdO, SnO{sub 2}, SnO, In{sub 2}O{sub 3}, and SiO{sub 2}. The Bethe-Salpeter equation is solved to account for excitonic effects in the calculation of the frequency-dependent absorption coefficients. We show that the HSE+G{sub 0}W{sub 0} approach and the solution of the Bethe-Salpeter equation are very well-suited to describe the electronic structure and the optical properties of various transparent conducting oxides in good agreement with experiment.

  16. Synthesis of Methanol and Dimethyl Ether from Syngas over Pd/ZnO/Al2O3 Catalysts

    SciTech Connect (OSTI)

    Lebarbier, Vanessa MC; Dagle, Robert A.; Kovarik, Libor; Lizarazo Adarme, Jair A.; King, David L.; Palo, Daniel R.

    2012-10-01T23:59:59.000Z

    A Pd/ZnO/Al2O3 catalyst was developed for the synthesis of methanol and dimethyl ether (DME) from syngas. Studied were temperatures of operation ranging from 250C to 380C. High temperatures (e.g. 380C) are necessary when combining methanol and DME synthesis with a methanol to gasoline (MTG) process in a single reactor bed. A commercial Cu/ZnO/Al2O3 catalyst, utilized industrially for the synthesis of methanol at 220-280C, suffers from a rapid deactivation when the reaction is conducted at high temperature (>320C). On the contrary, a Pd/ZnO/Al2O3 catalyst was found to be highly stable for methanol and DME synthesis at 380C. The Pd/ZnO/Al2O3 catalyst was thus further investigated for methanol and DME synthesis at P=34-69 bars, T= 250-380C, GHSV= 5 000-18 000 h-1, and molar feeds H2/CO= 1, 2, and 3. Selectivity to DME increased with decreasing operating temperature, and increasing operating pressure. Increased GHSVs and H2/CO syngas feed ratios also enhanced DME selectivity. Undesirable CH4 formation was observed, however, can be minimized through choice of process conditions and by catalyst design. By studying the effect of the Pd loading and the Pd:Zn molar ratio the formulation of the Pd/ZnO/Al2O3 catalyst was optimized. A catalyst with 5% Pd and a Pd:Zn molar ratio of 0.25:1 has been identified as the preferred catalyst. Results indicate that PdZn particles are more active than Pd particles for the synthesis of methanol and less active for CH4 formation. A correlation between DME selectivity and the concentration of acid sites of the catalysts has been established. Hence, two types of sites are required for the direct conversion of syngas to DME: 1) PdZn particles are active for the synthesis of methanol from syngas, and 2) acid sites which are active for the conversion of methanol to DME. Additionally, CO2 formation was problematic as PdZn was found to be active for the water-gas-shift (WGS) reaction, under all the conditions evaluated.

  17. The effect of Cu/Zn molar ratio on CO{sub 2} hydrogenation over Cu/ZnO/ZrO{sub 2}/Al{sub 2}O{sub 3} catalyst

    SciTech Connect (OSTI)

    Shaharun, Salina, E-mail: salinashaharun@gmail.com, E-mail: maizats@petronas.com.my; Shaharun, Maizatul S., E-mail: salinashaharun@gmail.com, E-mail: maizats@petronas.com.my; Taha, Mohd F., E-mail: faisalt@petronas.com.my [Department of Fundamental and Applied Science, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia); Mohamad, Dasmawati, E-mail: dasmawati@kck.usm.my [School of Dental Sciences, Health Campus, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan (Malaysia)

    2014-10-24T23:59:59.000Z

    Catalytic hydrogenation of carbon dioxide (CO{sub 2}) to methanol is an attractive way to recycle and utilize CO{sub 2}. A series of Cu/ZnO/Al{sub 2}O{sub 3}/ZrO{sub 2} catalysts (CZAZ) containing different molar ratios of Cu/Zn were prepared by the co-precipitation method and investigated in a stirred slurry autoclave system. The catalysts were characterized by temperature-programmed reduction (TPR), field emission scanning electron microscopy-energy dispersive analysis (FESEM-EDX), X-ray diffraction (XRD) and N{sub 2} adsorption-desorption. Higher surface area, SA{sub BET} values (42.659.9 m{sup 2}/g) are recorded at low (1) and high (5) Cu/Zn ratios with the minimum value of 35.71 m{sup 2}/g found for a Cu/Zn of 3. The reducibility of the metal oxides formed after calcination of catalyst samples was also affected due to change in metal-support interaction. At a low reaction temperature of 443 K, total gas pressure of 3.0 MPa and 0.1 g/mL of the CZAZ catalyst, the selectivity to methanol decreased as the Cu/Zn molar ratio increased, and the maximum selectivity of 67.73 was achieved at Cu/Zn molar ratio of 1. With a reaction time of 3h, the best performing catalyst was CZAZ75 with Cu/Zn molar ratio of 5 giving methanol yield of 79.30%.

  18. Synthesis of ZnO nanorodnanosheet composite via facile hydrothermal method and their photocatalytic activities under visible-light irradiation

    SciTech Connect (OSTI)

    Tan, Wai Kian [Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8580 (Japan); Abdul Razak, Khairunisak; Lockman, Zainovia [School of Materials and Mineral Resources, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Pulau Pinang (Malaysia); Kawamura, Go; Muto, Hiroyuki [Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8580 (Japan); Matsuda, Atsunori, E-mail: matsuda@ee.tut.ac.jp [Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8580 (Japan)

    2014-03-15T23:59:59.000Z

    ZnO composite films consisting of ZnO nanorods and nanosheets were prepared by low-temperature hydrothermal processing at 80 C on seeded glass substrates. The seed layer was coated on glass substrates by solgel dip-coating and pre-heated at 300 C for 10 min prior to hydrothermal growth. The size of the grain formed after pre-heat treatment was ?40 nm. A preferred orientation seed layer at the c-axis was obtained, which promoted vertical growth of the ZnO nanorod arrays and formation of the ZnO nanosheets. X-ray diffraction patterns and high-resolution transmission electron microscope (HR-TEM) images confirmed that the ZnO nanorods and nanosheets consist of single crystalline and polycrystalline structures, respectively. Room temperature photoluminescence spectra of the ZnO nanorodnanosheet composite films exhibited band-edge ultraviolet (UV) and visible emission (blue and green) indicating the formation of ZnO crystals with good crystallinity and are supported by Raman scattering results. The formation of one-dimensional (1D) ZnO nanorod arrays and two-dimensional (2D) ZnO nanosheet films using seeded substrates in a single low-temperature hydrothermal step would be beneficial for realization of device applications that utilize substrates with limited temperature stability. The ZnO nanorods and nanosheets composite structure demonstrated higher photocatalytic activity during degradation of aqueous methylene blue under visible-light irradiation. -- Graphical abstract: Schematic illustration of ZnO nanorodnanosheet composite structure formation by hydrothermal at low-temperature of 80 C against time. Highlights: Novel simultaneous formation of ZnO nanorods and nanosheets composite structure. Facile single hydrothermal step formation at low-temperature. Photoluminescence showed ultraviolet and visible emission. Feasible application on substrates with low temperature stability. Improved photocatalytic activity under visible-light irradiation.

  19. JOURNAL DE PHYSIQUE Collogue CI, supplement au n 4, Tome 38, Avril 1977, page Cl-17 HIGH-FREQUENCY PROPERTIES OF Ni-Zn-Co FERRITES

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    -FREQUENCY PROPERTIES OF Ni-Zn-Co FERRITES IN RELATION TO IRON CONTENT AND MICROSTRUCTURE J. G. M. DE LAU (*) and A-substitution d'ions Co3+ et des ions Co2+ dans des ferrites de Ni-Zn ainsi que la réduction de la taille des+ ions in addition to Co2+ in Ni-Zn ferrites and the reduction of grain size lead to a great improvement

  20. Impact of surface morphology of Si substrate on performance of Si/ZnO heterojunction devices grown by atomic layer deposition technique

    SciTech Connect (OSTI)

    Hazra, Purnima; Singh, Satyendra Kumar [Department of Electronics and Communication Engineering, Motilal Neheru National Institute of Technology, Allahabad 211004 (India); Jit, Satyabrata, E-mail: sjit.ece@itbhu.ac.in [Department of Electronics Engineering, Indian Institute of Technology (BHU), Varanasi 221005 (India)

    2015-01-01T23:59:59.000Z

    In this paper, the authors have investigated the structural, optical, and electrical characteristics of silicon nanowire (SiNW)/zinc oxide (ZnO) coreshell nanostructure heterojunctions and compared their characteristics with Si/ZnO planar heterojunctions to investigate the effect of surface morphology of Si substrate in the characteristics of Si/ZnO heterojunction devices. In this work, ZnO thin film was conformally deposited on both p-type ?100? planar Si substrate and substrate with vertically aligned SiNW arrays by atomic layer deposition (ALD) method. The x-ray diffraction spectra show that the crystalline structures of Si/ZnO heterojunctions are having (101) preferred orientation, whereas vertically oriented SiNW/ZnO coreshell heterojunctions are having (002)-oriented wurtzite crystalline structures. The photoluminescence (PL) spectra of Si/ZnO heterojunctions show a very sharp single peak at 377?nm, corresponding to the bandgap of ZnO material with no other defect peaks in visible region; hence, these devices can have applications only in UV region. On the other hand, SiNW/ZnO heterojunctions are having band-edge peak at 378?nm along with a broad emission band, spreading almost throughout the entire visible region with a peak around 550?nm. Therefore, ALD-grown SiNW/ZnO heterojunctions can emit green and red light simultaneously. Reflectivity measurement of the heterojunctions further confirms the enhancement of visible region peak in the PL spectra of SiNW/ZnO heterojunctions, as the surface of the SiNW/ZnO heterojunctions exhibits extremely low reflectance (<3%) in the visible wavelength region compared to Si/ZnO heterojunctions (>20%). The currentvoltage characteristics of both Si/ZnO and SiNW/ZnO heterojunctions are measured with large area ohmic contacts on top and bottom of the structure to compare the electrical characteristics of the devices. Due to large surface to-volume ratio of SiNW/ZnO coreshell heterojunction devices, the output current rating is about 130 times larger compared to their planar version at 2 V forward bias voltage. This higher output current rating can be exploited for fabricating high-performance nanoelectronic and optoelectronic devices in near future.

  1. FINAL REPORT OF RESEARCH ON CuxS/ (Cd,Zn)S PHOTOVOLTAIC SOLAR ENERGY CONVERTERS 3/77 - 9/79

    E-Print Network [OSTI]

    Chin, B.L.

    2013-01-01T23:59:59.000Z

    S/(Cd,Zn)S PHOTOVOLTAIC SOLAR ENERGY CONVERTERS 3/77 - 9/79Research on Photovoltaic Solar Energy Converters CuxSI(Cd~

  2. Hydrogen induced electric conduction in undoped ZnO and Ga-doped ZnO thin films: Creating native donors via reduction, hydrogen donors, and reactivating extrinsic donors

    SciTech Connect (OSTI)

    Akazawa, Housei, E-mail: akazawa.housei@lab.ntt.co.jp [NTT Microsystem Integration Laboratories, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198 (Japan)

    2014-09-01T23:59:59.000Z

    The manner in which hydrogen atoms contribute to the electric conduction of undoped ZnO and Ga-doped ZnO (GZO) films was investigated. Hydrogen atoms were permeated into these films through annealing in an atmospheric H{sub 2} ambient. Because the creation of hydrogen donors competes with the thermal annihilation of native donors at elevated temperatures, improvements to electric conduction from the initial state can be observed when insulating ZnO films are used as samples. While the resistivity of conductive ZnO films increases when annealing them in a vacuum, the degree of increase is mitigated when they are annealed in H{sub 2}. Hydrogenation of ZnO crystals was evidenced by the appearance of OH absorption signals around a wavelength of 2700?nm in the optical transmittance spectra. The lowest resistivity that was achieved by H{sub 2} annealing was limited to 12??10{sup ?2} ? cm, which is one order of magnitude higher than that by native donors (23??10{sup ?3} ? cm). Hence, all native donors are converted to hydrogen donors. In contrast, GZO films that have resistivities yet to be improved become more conductive after annealing in H{sub 2} ambient, which is in the opposite direction of GZO films that become more resistive after vacuum annealing. Hydrogen atoms incorporated into GZO crystals should assist in reactivating Ga{sup 3+} donors.

  3. Visible light plasmonic heating of Au-ZnO for the catalytic reduction of CO{sub 2}

    SciTech Connect (OSTI)

    Wang, Congjun; Ranasingha, Oshadha; Natesakhawat, Sittichai; Ohodnicki, Paul R.; Ohodnicki, Andio, Mark; Lewis, James; P Matranga, Christopher

    2013-05-01T23:59:59.000Z

    Plasmonic excitation of Au nanoparticles attached to the surface of ZnO catalysts using low power 532 nm laser illumination leads to significant heating of the catalyst and the conversion of CO{sub 2} and H{sub 2} reactants to CH{sub 4} and CO products. Temperature-calibrated Raman spectra of ZnO phonons show that intensity-dependent plasmonic excitation can controllably heat AuZnO from 30 to #1;~600 {degrees}#3;C and simultaneously tune the CH{sub 4} : CO product ratio. The laser induced heating and resulting CH{sub 4} : CO product distribution agrees well with predictions from thermodynamic models and temperatureprogrammed reaction experiments indicating that the reaction is a thermally driven process resulting from the plasmonic heating of the AuZnO. The apparent quantum yield for CO{sub 2} conversion under continuous wave (cw) 532 nm laser illumination is 0.030%. The AuZnO catalysts are robust and remain active after repeated laser exposure and cycling. The light intensity required to initiate CO{sub 2} reduction is low (#1;~2.5 x#4; 10{sup 5} W m{sup #5;-2}) and achievable with solar concentrators. Our results illustrate the viability of plasmonic heating approaches for CO{sub 2} utilization and other practical thermal catalytic applications.

  4. Photoluminescence properties and energy levels of RE (RE?=?Pr, Sm, Er, Tm) in layered-CaZnOS oxysulfide

    SciTech Connect (OSTI)

    Zhang, Zhi-Jun, E-mail: zhangzj@mail.sic.ac.cn [Key Laboratory of Transparent Opto-Functional Inorganic Materials of Chinese Academy of Sciences, Shanghai Institute of Ceramics, Shanghai 200050 (China); Feng, Ang; Chen, Xiang-Yang [Key Laboratory of Transparent Opto-Functional Inorganic Materials of Chinese Academy of Sciences, Shanghai Institute of Ceramics, Shanghai 200050 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); Zhao, Jing-Tai, E-mail: jtzhao@mail.sic.ac.cn [Key Laboratory of Transparent Opto-Functional Inorganic Materials of Chinese Academy of Sciences, Shanghai Institute of Ceramics, Shanghai 200050 (China); School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China)

    2013-12-07T23:59:59.000Z

    RE{sup 3+} (RE?=?Pr, Sm, Er, Tm)-activated CaZnOS samples were prepared by a solid-state reaction method at high temperature, and their photoluminescence properties were investigated. Doping with RE{sup 3+} (RE?=?Pr, Sm, Er, Tm) into layered-CaZnOS resulted in typical RE{sup 3+} (RE?=?Pr, Sm, Er, Tm) f-f line absorptions and emissions, as well as the charge transfer band of Sm{sup 3+} at about 3.3?eV. The energy level scheme containing the position of the 4f and 5d levels of all divalent and trivalent lanthanide ions with respect to the valence and conduction bands of CaZnOS has been constructed based on the new data presented in this work, together with the data from literature on Ce{sup 3+} and Eu{sup 2+} doping in CaZnOS. The detailed energy level scheme provides a platform for interpreting the optical spectra and could be used to comment on the valence stability of the lanthanide ions in CaZnOS.

  5. MoS{sub 2}@ZnO nano-heterojunctions with enhanced photocatalysis and field emission properties

    SciTech Connect (OSTI)

    Tan, Ying-Hua; Yu, Ke, E-mail: yk5188@263.net; Li, Jin-Zhu; Fu, Hao; Zhu, Zi-Qiang [Key Laboratory of Polar Materials and Devices (Ministry of Education of China), Department of Electronic Engineering, East China Normal University, Shanghai 200241 (China)

    2014-08-14T23:59:59.000Z

    The molybdenum disulfide (MoS{sub 2})@ZnO nano-heterojunctions were successfully fabricated through a facile three-step synthetic process: prefabrication of the ZnO nanoparticles, the synthesis of MoS{sub 2} nanoflowers, and the fabrication of MoS{sub 2}@ZnO heterojunctions, in which ZnO nanoparticles were uniformly self-assembled on the MoS{sub 2} nanoflowers by utilizing polyethyleneimine as a binding agent. The photocatalytic activities of the composite samples were evaluated by monitoring the photodegradation of methylene blue (MB). Compared with pure MoS{sub 2} nanoflowers, the composites show higher adsorption capability in dark and better photocatalytic efficiency due to the increased specific surface area and improved electron-hole pair separation. After irradiation for 100?min, the remaining MB in solution is about 7.3%. Moreover, the MoS{sub 2}@ZnO heterojunctions possess enhanced field emission properties with lower turn-on field of 3.08?V ?m{sup ?1}and lower threshold field of 6.9?V ?m{sup ?1} relative to pure MoS{sub 2} with turn-on field of 3.65?V ?m{sup ?1} and threshold field of 9.03?V ?m{sup ?1}.

  6. Microstructure evolution of Al/Mg butt joints welded by gas tungsten arc with Zn filler metal

    SciTech Connect (OSTI)

    Liu Fei; Zhang Zhaodong; Liu Liming, E-mail: liulm@dlut.edu.cn

    2012-07-15T23:59:59.000Z

    Based on the idea of alloying welding seam, Gas tungsten arc welding method with pure Zn filler metal was chosen to join Mg alloy and Al alloy. The microstructures, phases, element distribution and fracture morphology of welding seams were examined. The results indicate that there was a transitional zone in the width of 80-100 {mu}m between the Mg alloy substrate and fusion zone. The fusion zone was mainly composed of MgZn{sub 2}, Zn-based solid solution and Al-based solid solution. The welding seam presented distinct morphology in different location owning to the quite high cooling rate of the molten pool. The addition of Zn metal could prevent the formation of Mg-Al intermetallics and form the alloyed welding seam during welding. Therefore, the tensile strengths of joints have been significantly improved compared with those of gas tungsten arc welded joints without Zn metal added. Highlights: Black-Right-Pointing-Pointer Mg alloy AZ31B and Al alloy 6061 are welded successfully. Black-Right-Pointing-Pointer Zinc wire is employed as a filler metal to form the alloyed welding seam. Black-Right-Pointing-Pointer An alloyed welding seam is benefit for improving of the joint tensile strength.

  7. First-principles study of electronic and optical properties in wurtzite Zn_{1-x}Cd_xO

    E-Print Network [OSTI]

    Zhang, X D; Li, W X; Liu, C L; 10.1063/1.2901033

    2012-01-01T23:59:59.000Z

    A first-principles study has been performed to evaluate the electronic and optical properties of wurtzite Zn1-xCdxO up to x=0.25. We have employed the Perdew-Burke-Ernzerhof (PBE) form of generalized gradient approximation within the framework of density functional theory (DFT). Calculations have been carried out in different configurations. With the increasing Cd concentrations, the band gap of Zn1-xCdxO is decreased due to the increase of s states in conduction band. The results of imaginary part of dielectric function indicate that the optical transition between O 2p states in the highest valence band and Zn 4s states in the lowest conduction band has shifted to low energy range as the Cd concentrations increase. Besides, the optical band gap decreases from 3.2 to 2.84 eV with increasing Cd concentrations from 0 to 0.25. Meanwhile, the bowing parameter b, which has been obtained by fitting the results of optical band gap, is about 1.21 eV. The optical constants of pure ZnO and Zn0.75Cd0.25O, such as optica...

  8. Thermal conductivity of Zn{sub 4{minus}x}Cd{sub x}Sb{sub 3} solid solutions

    SciTech Connect (OSTI)

    Caillat, T.; Borshchevsky, A.; Fleurial, J.P.

    1997-07-01T23:59:59.000Z

    {beta}-Zn{sub 4}Sb{sub 3} was recently identified at the Jet Propulsion Laboratory as a new high performance p-type thermoelectric material with a maximum dimensionless thermoelectric figure of merit ZT of 1.4 at a temperature of 673K. A usual approach, used for many state-of-the-art thermoelectric materials, to further improve ZT values is to alloy {beta}-Zn{sub 4}Sb{sub 3} with isostructural compounds because of the expected decrease in lattice thermal conductivity. The authors have grown Zn{sub 4{minus}x}Cd{sub x}Sb{sub 3} crystals with 0.2 {le} x < 1.2 and measured their thermal conductivity from 10 to 500K. The thermal conductivity values of Zn{sub 4{minus}x}Cd{sub x}Sb{sub 3} alloys are significantly lower than those measured for {beta}-Zn{sub 4}Sb{sub 3} and are comparable to its calculated minimum thermal conductivity. A strong atomic disorder is believed to be primarily at the origin of the very low thermal conductivity of these materials which are also fairly good electrical conductors and are therefore excellent candidates for thermoelectric applications.

  9. Computer simulation of the energy gap in ZnO- and TiO{sub 2}-based semiconductor photocatalysts

    SciTech Connect (OSTI)

    Skorikov, N. A., E-mail: nskorikov@gmail.com; Korotin, M. A.; Kurmaev, E. Z. [Russian Academy of Sciences, Institute of Metal Physics, Ural Branch (Russian Federation); Cholakh, S. O. [Ural Federal University (Russian Federation)

    2012-12-15T23:59:59.000Z

    Ab initio calculations of the electronic structures of binary ZnO- and TiO{sub 2}-based oxides are performed to search for optimum dopants for efficient absorption of the visible part of solar radiation. Light elements B, C, and N are chosen for anion substitution. Cation substitution is simulated by 3d elements (Cr, Mn, Fe, Co) and heavy metals (Sn, Sb, Pb, Bi). The electronic structures are calculated by the full-potential linearized augmented plane wave method using the modified Becke-Johnson exchange-correlation potential. Doping is simulated by calculating supercells Zn{sub 15}D{sub 1}O{sub 16}, Zn{sub 16}O{sub 15}D{sub 1}, Ti{sub 15}D{sub 1}O{sub 32}, and Ti{sub 8}O{sub 15}D{sub 1}, where one-sixteenth of the metal (Ti, Zn) or oxygen atoms is replaced by dopant atoms. Carbon and antimony are found to be most effective dopants for ZnO: they form an energy gap {Delta}E = 1.78 and 1.67 eV, respectively. For TiO{sub 2}, nitrogen is the most effective dopant ({Delta}E = 1.76 eV).

  10. Zinc vacancy and erbium cluster jointly promote ferromagnetism in erbium-doped ZnO thin film

    SciTech Connect (OSTI)

    Chen, Hong-Ming; Zhou, Ren-Wei; Li, Fei [Shanghai Institute of Ceramics, Chinese Academy of Sciences, 215 Chengbei Road, Shanghai 201800 (China) [Shanghai Institute of Ceramics, Chinese Academy of Sciences, 215 Chengbei Road, Shanghai 201800 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Liu, Xue-Chao, E-mail: xcliu@mail.sic.ac.cn; Zhuo, Shi-Yi; Shi, Er-Wei [Shanghai Institute of Ceramics, Chinese Academy of Sciences, 215 Chengbei Road, Shanghai 201800 (China)] [Shanghai Institute of Ceramics, Chinese Academy of Sciences, 215 Chengbei Road, Shanghai 201800 (China); Xiong, Ze [Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong (China)] [Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong (China)

    2014-04-15T23:59:59.000Z

    Zn{sub 1-x}Er{sub x}O (0.005 ? x ? 0.04) thin films have been prepared by inductively coupled plasma enhanced physical vapor deposition method. Ferromagnetism, crystal structure, microstructure and photoluminescence properties of the films were characterized. It is found that the chemical valence state of Er is trivalent, and the Er{sup 3+} cations play an important role in ferromagnetism. Both saturated magnetization (M{sub s}) and zinc vacancy (V{sub Zn}) are decreased with the increase of x from 0.005 to 0.03. However, further increasing x to 0.04, the M{sub s} is quenched due to the generation of Er clusters. It reveals that the intensity of M{sub s} is not only associated with the V{sub Zn} concentration, but also related to the Er clusters. The V{sub Zn} concentration and the Er clusters can jointly boost the ferromagnetism in the Zn{sub 1-x}Er{sub x}O thin films.

  11. Characterization of piesoelectric ZnO thin films and the fabrication of piezoelectric micro-cantilevers

    SciTech Connect (OSTI)

    Johnson, Raegan Lynn

    2005-08-01T23:59:59.000Z

    In Atomic Force Microscopy (AFM), a microcantilever is raster scanned across the surface of a sample in order to obtain a topographical image of the sample's surface. In a traditional, optical AFM, the sample rests on a bulk piezoelectric tube and a control loop is used to control the tip-sample separation by actuating the piezo-tube. This method has several disadvantages--the most noticeable one being that response time of the piezo-tube is rather long which leads to slow imaging speeds. One possible solution aimed at improving the speed of imaging is to incorporate a thin piezoelectric film on top of the cantilever beam. This design not only improves the speed of imaging because the piezoelectric film replaces the piezo-tube as an actuator, but the film can also act as a sensor. In addition, the piezoelectric film can excite the cantilever beam near its resonance frequency. This project aims to fabricate piezoelectric microcantilevers for use in the AFM. Prior to fabricating the cantilevers and also part of this project, a systematic study was performed to examine the effects of deposition conditions on the quality of piezoelectric ZnO thin films deposited by RF sputtering. These results will be presented. The deposition parameters that produced the highest quality ZnO film were used in the fabrication of the piezoelectric cantilevers. Unfortunately, the fabricated cantilevers warped due to the intrinsic stress of the ZnO film and were therefore not usable in the AFM. The complete fabrication process will be detailed, the results will be discussed and reasons for the warping will be examined.

  12. Tuning of defects in ZnO nanorod arrays used in bulk heterojunction solar cells

    E-Print Network [OSTI]

    Iza, Diana C; Muoz-Rojas, David; Jia, Quanxi; Swartzentruber, Brian; MacManus-Driscoll, Judith L

    2012-11-27T23:59:59.000Z

    by radio frequency magnetron sputtering. J Mater Res 2005, 20:15741579. 55. Cui J: Zinc oxide nanowires. Mater Charact 2012, 64:4352. 56. Fan Z, Wang D, Chang P-C, Tseng W-Y, Lu JG: ZnO nanowire field-effect transistor and oxygen sensing property. Appl... to 130 nm in diameter and ca. 800 nm in length. Figure 1d,e shows cross-sectional images of the solar cell devices produced herein, which will be discussed later. Results and discussion Firstly, we present the PL data on our samples together with IR...

  13. High Resolution Optically Addressed Spatial Light Modulator based on ZnO Nanoparticles

    E-Print Network [OSTI]

    Shrestha, Pawan Kumar; Chun, Young Tea; Chu, Daping

    2015-01-01T23:59:59.000Z

    temperatures. (d) Temporal current response with and without illumination. Samples are illuminated by 10 mW cm -2 of 365 nm light emitting diode with 6 V dc being applied throughout. Electrical characterization For conductivity measurement, two rectangular... of the corresponding dark/photo currents of the ITO-ZnO-ITO structures are carried out using Agilent 4156 together with a 365 nm light emitting diode light source of 2 mW cm-2. The conductivity, ? , of the sample is calculated as, dI LtV? ? (2) where, d...

  14. Light induced instability mechanism in amorphous InGaZn oxide semiconductors

    SciTech Connect (OSTI)

    Robertson, John; Guo, Yuzheng [Department of Engineering, Cambridge University, Cambridge CB2 1PZ (United Kingdom)

    2014-04-21T23:59:59.000Z

    A model of the negative bias illumination stress instability in InGaZn oxide is presented, based on the photo-excitation of electrons from oxygen interstitials. The O interstitials are present to compensate hydrogen donors. The O interstitials are found to spontaneously form in O-rich conditions for Fermi energies at the conduction band edge, much more easily that in related oxides. The excited electrons give rise to a persistent photoconductivity due to an energy barrier to recombination. The formation energy of the O interstitials varies with their separation from the H donors, which leads to a voltage stress dependence on the compensation.

  15. Plasma spectroscopic study of an electrodeless HID lamp containing Tl and Zn

    SciTech Connect (OSTI)

    Takeda, Mamoru; Horii, Shigeru; Hochi, Akira [Matsushita Electric Industrial Co., Ltd., Kyoto (Japan). Lighting Research Lab.

    1996-12-31T23:59:59.000Z

    Recently the electrodeless HID lamps excited by microwaves have been studied intensively. Tl is well known as a material having strong green emission lines. In this study, Tl spectra excited by microwaves were reported in the cases of Tl only and Tl + Zn. Using the Elenbaas`s method of high pressure Hg lamp, the cause of Tl continuous spectrum was examined. From the ratio of radiative intensities of two lines, an average arc temperature in the bulb was estimated. Then excitation level of the continuous emission spectrum near the 600nm wavelength was calculated from the dependence of the radiative intensities on these arc temperatures.

  16. Photoluminescence due to inelastic exciton-exciton scattering in ZnMgO-alloy thin film

    SciTech Connect (OSTI)

    Chia, C. H.; Chen, J. N.; Hu, Y. M. [Department of Applied Physics, National University of Kaohsiung, Kaohsiung 81148, Taiwan (China)

    2011-09-26T23:59:59.000Z

    We studied the photoluminescence of ZnMgO thin film, grown by the radiofrequency sputtering method, as a function of excitation intensity and temperature. As the excitation intensity increases, a nonlinear emission band caused by the radiative recombination of the inelastic exciton-exciton scattering was detected at low temperature. We found that the inelastic exciton-exciton scattering process can only persist up to T {approx} 260 K. The nonlinear emission band observed at room temperature is due to the radiative recombination of the electron-hole plasma.

  17. Characterization of ZnSe scintillating bolometers for Double Beta Decay

    E-Print Network [OSTI]

    C. Arnaboldi; S. Capelli; O. Cremonesi; L. Gironi; M. Pavan; G. Pessina; S. Pirro

    2010-06-30T23:59:59.000Z

    ZnSe scintillating bolometers are good candidates for future Double Beta Decay searches, because of the 82Se high Q-value and thanks to the possibility of alpha background rejection on the basis of the scintillation signal. In this paper we report the characteristics and the anomalies observed in an extensive study of these devices. Among them, an unexpected high emission from alpha particles, accompanied with an unusual pattern of the light vs. heat scatter plot. The perspectives for the application of this kind of detectors to search for the Neutrinoless Double Beta Decay of 82Se are presented.

  18. Core-shell ITO/ZnO/CdS/CdTe nanowire solar cells

    SciTech Connect (OSTI)

    Williams, B. L.; Phillips, L.; Major, J. D.; Durose, K. [Stephenson Institute for Renewable Energy, University of Liverpool, Chadwick Building, Peach St., Liverpool L69 7ZF (United Kingdom); Taylor, A. A.; Mendis, B. G.; Bowen, L. [G. J. Russell Microscopy Facility, University of Durham, South Road, Durham DH1 3LE (United Kingdom)

    2014-02-03T23:59:59.000Z

    Radial p-n junction nanowire (NW) solar cells with high densities of CdTe NWs coated with indium tin oxide (ITO)/ZnO/CdS triple shells were grown with excellent heterointerfaces. The optical reflectance of the devices was lower than for equivalent planar films by a factor of 100. The best efficiency for the NW solar cells was ??=?2.49%, with current transport being dominated by recombination, and the conversion efficiencies being limited by a back contact barrier (?{sub B}?=?0.52?eV) and low shunt resistances (R{sub SH}?

  19. PROPRITS MAGNTIQUES DU FERRITE DE ZINC (Fe2 O3.Zn O)

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    PROPRI?T?S MAGN?TIQUES DU FERRITE DE ZINC (Fe2 O3.Zn O) EN RELATION AVEC SA STRUCTURE Par CH. GUILLAUD et M. SAGE. Sommaire. - On a préparé des ferrites de zinc et étudié leurs propriétés magnétiques distribution des ions dans le réseau. Nous avons préparé ce ferrite par les méthodes classiques du mélange d

  20. Self-erasing and rewritable wettability patterns on ZnO thin films

    SciTech Connect (OSTI)

    Kekkonen, Ville; Hakola, Antti; Kajava, Timo; Ras, Robin H. A. [Department of Applied Physics, Aalto University, P.O. Box 15100, FI-00076 Aalto, Espoo (Finland); Sahramo, Elina; Malm, Jari; Karppinen, Maarit [Department of Chemistry, Aalto University, P.O. Box 16100, FI-00076 Aalto, Espoo (Finland)

    2010-07-26T23:59:59.000Z

    Self-erasing patterns allow a substrate to be patterned multiple times or could store temporary information for secret communications, and are mostly based on photochromic molecules to change the color of the pattern. Herein we demonstrate self-erasing patterns of wettability on thin ZnO films made by atomic layer deposition. Hydrophilic patterns are written using UV light and decay spontaneously, i.e. become hydrophobic, or are erased aided by vacuum conditions or heat. We demonstrate that these patterns can be applied for channels to confine flow of water without physical walls.

  1. Bendable ZnO thin film surface acoustic wave devices on polyethylene terephthalate substrate

    SciTech Connect (OSTI)

    He, Xingli; Guo, Hongwei; Chen, Jinkai; Wang, Wenbo; Xuan, Weipeng; Xu, Yang, E-mail: yangxu-isee@zju.edu.cn, E-mail: jl2@bolton.ac.uk [Department of Info. Sci. and Electron. Eng., Zhejiang University and Cyrus Tang Center for Sensor Mater. and Appl., 38 Zheda Road, Hangzhou 310027 (China); Luo, Jikui, E-mail: yangxu-isee@zju.edu.cn, E-mail: jl2@bolton.ac.uk [Department of Info. Sci. and Electron. Eng., Zhejiang University and Cyrus Tang Center for Sensor Mater. and Appl., 38 Zheda Road, Hangzhou 310027 (China); Institute of Renew. Energ. and Environ. Tech., University of Bolton, Deane Road, Bolton BL3 5AB (United Kingdom)

    2014-05-26T23:59:59.000Z

    Bendable surface acoustic wave (SAW) devices were fabricated using high quality c-axis orientation ZnO films deposited on flexible polyethylene terephthalate substrates at 120?C. Dual resonance modes, namely, the zero order pseudo asymmetric (A{sub 0}) and symmetric (S{sub 0}) Lamb wave modes, have been obtained from the SAW devices. The SAW devices perform well even after repeated flexion up to 2500??? for 100 times, demonstrating its suitability for flexible electronics application. The SAW devices are also highly sensitive to compressive and tensile strains, exhibiting excellent anti-strain deterioration property, thus, they are particularly suitable for sensing large strains.

  2. Optical channel waveguides written by high repetition rate femtosecond laser irradiation in Li-Zn fluoroborate glass

    E-Print Network [OSTI]

    Thomas, Sunil; Solis, Javier; Biju, P R; Unnikrishnan, N V

    2015-01-01T23:59:59.000Z

    Low loss, optical channel waveguides have been successfully produced by high repetition rate, femtosecond laser inscription in a Li-Zn fluoroborate glass (64.9B2O3 + 25Li2O + 10ZnF2 + 0.1Er2O3). High quality waveguides were produced at 500 kHz, 1 MHz and 2 MHz laser repetition rates, showing a refractive index contrast in the range of 3-6 x 10-3 depending on various fluences. Dependence of experimental parameters such as average laser power, pulse repetition rate and writing speed on the properties of fabricated waveguides has been discussed. The comparison of optical and compositional characterization techniques evidences an enrichment of B and Zn in the guiding region, while F migrates to the heat diffused region of the written structure.

  3. Performance of ZnMoO4 crystal as cryogenic scintillating bolometer to search for double beta decay of molybdenum

    E-Print Network [OSTI]

    L. Gironi; C. Arnaboldi; J. W. Beeman; O. Cremonesi; F. A. Danevich; V. Ya. Degoda; L. I. Ivleva; L. L. Nagornaya; M. Pavan; G. Pessina; S. Pirro; V. I. Tretyak; I. A. Tupitsyna

    2010-10-01T23:59:59.000Z

    Zinc molybdate (ZnMoO4) single crystals were grown for the first time by the Czochralski method and their luminescence was measured under X ray excitation in the temperature range 85-400 K. Properties of ZnMoO4 crystal as cryogenic low temperature scintillator were checked for the first time. Radioactive contamination of the ZnMoO4 crystal was estimated as <0.3 mBq/kg (228-Th) and 8 mBq/kg (226-Ra). Thanks to the simultaneous measurement of the scintillation light and the phonon signal, the alpha particles can be discriminated from the gamma/beta interactions, making this compound extremely promising for the search of neutrinoless Double Beta Decay of 100-Mo. We also report on the ability to discriminate the alpha-induced background without the light measurement, thanks to a different shape of the thermal signal that characterizes gamma/beta and alpha particle interactions.

  4. Plasmonic materials based on ZnO films and their potential for developing broadband middle-infrared absorbers

    SciTech Connect (OSTI)

    Kesim, Yunus E., E-mail: yunus.kesim@bilkent.edu.tr; Battal, Enes [Department of Electrical and Electronics Engineering, Bilkent University, Ankara, 06800 (Turkey); UNAM-National Nanotechnology Research Center, Bilkent University, Ankara, 06800 (Turkey); Okyay, Ali K. [Department of Electrical and Electronics Engineering, Bilkent University, Ankara, 06800 (Turkey); UNAM-National Nanotechnology Research Center, Bilkent University, Ankara, 06800 (Turkey); Institute of Materials Science and Nanotechnology, Bilkent University, Ankara, 06800 (Turkey)

    2014-07-15T23:59:59.000Z

    Noble metals such as gold and silver have been extensively used for plasmonic applications due to their ability to support plasmons, yet they suffer from high intrinsic losses. Alternative plasmonic materials that offer low loss and tunability are desired for a new generation of efficient and agile devices. In this paper, atomic layer deposition (ALD) grown ZnO is investigated as a candidate material for plasmonic applications. Optical constants of ZnO are investigated along with figures of merit pertaining to plasmonic waveguides. We show that ZnO can alleviate the trade-off between propagation length and mode confinement width owing to tunable dielectric properties. In order to demonstrate plasmonic resonances, we simulate a grating structure and computationally demonstrate an ultra-wide-band (415 ?m) infrared absorber.

  5. One-photon band gap engineering of borate glass doped with ZnO for photonics applications

    SciTech Connect (OSTI)

    Abdel-Baki, Manal [Glass Department, National Research Centre, Dokki 12311 Giza (Egypt); Abdel-Wahab, Fathy A.; El-Diasty, Fouad [Physics Department, Faculty of Science, Ain Shams University, Abbasia, 11566 Cairo (Egypt)

    2012-04-01T23:59:59.000Z

    Lithium tungsten borate glass of the composition (0.56-x)B{sub 2}O{sub 3}-0.4Li{sub 2}O-xZnO-0.04WO{sub 3} (0 {<=}x{<=} 0.1 mol. %) is prepared for photonics applications. The glass is doped with ZnO to tune the glass absorption characteristics in a wide spectrum range (200-2500 nm). Chemical bond approach, including chemical structure, electronegativity, bond ionicity, nearest-neighbor coordination, and other chemical bonding aspect, is used to analyze and to explain the obtained glass properties such as: transmittance, absorption, electronic structure parameters (bandgap, Fermi level, and Urbach exciton-phonon coupling), Wannier free excitons excitation (applying Elliott's model), and two-photon absorption coefficient as a result of replacement of B{sub 2}O{sub 3} by ZnO.

  6. Reduction of surface leakage current by surface passivation of CdZn Te and other materials using hyperthermal oxygen atoms

    DOE Patents [OSTI]

    Hoffbauer, Mark A. (Los Alamos, NM); Prettyman, Thomas H. (Los Alamos, NM)

    2001-01-01T23:59:59.000Z

    Reduction of surface leakage current by surface passivation of Cd.sub.1-x Zn.sub.x Te and other materials using hyperthermal oxygen atoms. Surface effects are important in the performance of CdZnTe room-temperature radiation detectors used as spectrometers since the dark current is often dominated by surface leakage. A process using high-kinetic-energy, neutral oxygen atoms (.about.3 eV) to treat the surface of CdZnTe detectors at or near ambient temperatures is described. Improvements in detector performance include significantly reduced leakage current which results in lower detector noise and greater energy resolution for radiation measurements of gamma- and X-rays, thereby increasing the accuracy and sensitivity of measurements of radionuclides having complex gamma-ray spectra, including special nuclear materials.

  7. HAND-HELD GAMMA-RAY SPECTROMETER BASED ON HIGH-EFFICIENCY FRISCH-RING CdZnTe DETECTORS.

    SciTech Connect (OSTI)

    CUI,Y.

    2007-05-01T23:59:59.000Z

    Frisch-ring CdZnTe detectors have demonstrated good energy resolution, el% FWHM at 662 keV, and good efficiency for detecting gamma rays. This technique facilitates the application of CdZnTe materials for high efficiency gamma-ray detection. A hand-held gamma-ray spectrometer based on Frisch-ring detectors is being designed at Brookhaven National Laboratory. It employs an 8x8 CdZnTe detector array to achieve a high volume of 19.2 cm3, so that detection efficiency is significantly improved. By using the front-end ASICs developed at BNL, this spectrometer has a small profile and high energy resolution. The spectrometer includes signal processing circuit, digitization and storage circuit, high-voltage module, and USB interface. In this paper, we introduce the details of the system structure and report our test results with it.

  8. Interaction between O{sub 2} and ZnO films probed by time-dependent second-harmonic generation

    SciTech Connect (OSTI)

    Andersen, S. V., E-mail: sva@nano.aau.dk [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Department of Physics and Nanotechnology, Aalborg University, Skjernvej 4A, DK-9220 Aalborg st (Denmark); Vandalon, V.; Bosch, R. H. E. C.; Loo, B. W. H. van de; Kessels, W. M. M., E-mail: w.m.m.kessels@tue.nl [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Pedersen, K. [Department of Physics and Nanotechnology, Aalborg University, Skjernvej 4A, DK-9220 Aalborg st (Denmark)

    2014-02-03T23:59:59.000Z

    The interaction between O{sub 2} and ZnO thin films prepared by atomic layer deposition has been investigated by time-dependent second-harmonic generation, by probing the electric field induced by adsorbed oxygen molecules on the surface. The second-harmonic generated signal decays upon laser exposure due to two-photon assisted desorption of O{sub 2}. Blocking and unblocking the laser beam for different time intervals reveals the adsorption rate of O{sub 2} onto ZnO. The results demonstrate that electric field induced second-harmonic generation provides a versatile non-contact probe of the adsorption kinetics of molecules on ZnO thin films.

  9. Atom-probe tomographic study of interfaces of Cu{sub 2}ZnSnS{sub 4} photovoltaic cells

    SciTech Connect (OSTI)

    Tajima, S., E-mail: e0954@mosk.tytlabs.co.jp; Asahi, R.; Itoh, T.; Hasegawa, M.; Ohishi, K. [Toyota Central R and D Labs., Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192 (Japan); Isheim, D.; Seidman, D. N. [Northwestern University, Evanston, Illinois 60208-3108 (United States)

    2014-09-01T23:59:59.000Z

    The heterophase interfaces between the CdS buffer layer and the Cu{sub 2}ZnSnS{sub 4} (CZTS) absorption layers are one of the main factors affecting photovoltaic performance of CZTS cells. We have studied the compositional distributions at heterophase interfaces in CZTS cells using three-dimensional atom-probe tomography. The results demonstrate: (a) diffusion of Cd into the CZTS layer; (b) segregation of Zn at the CdS/CZTS interface; and (c) a change of oxygen and hydrogen concentrations in the CdS layer depending on the heat treatment. Annealing at 573?K after deposition of CdS improves the photovoltaic properties of CZTS cells probably because of the formation of a heterophase epitaxial junction at the CdS/CZTS interface. Conversely, segregation of Zn at the CdS/CZTS interface after annealing at a higher temperature deteriorates the photovoltaic properties.

  10. The effect of Au and Ni doping on the heavy fermion state of the Kondo lattice antiferromagnet CePtZn

    SciTech Connect (OSTI)

    Dhar, S. K., E-mail: sudesh@tifr.res.in [DCMPMS, T.I.F.R., Homi Bhabha Road, Colaba, Mumbai 400005 (India); Aoki, Y.; Suemitsu, B.; Miyazaki, R. [Department of Physics, Tokyo Metropolitan University, Minami-Ohsawa 1-1, Hachioji-Shi, Tokyo (Japan); Provino, A.; Manfrinetti, P. [Departimento Physica Chemicale, Universita di Genova, Via Dodecaneso, 16146 Genova (Italy)

    2014-05-07T23:59:59.000Z

    We have probed the effect of doping CePtZn with Au and Ni and also investigated in detail the magnetic behavior of the iso-structural CeAuZn. A magnetic ground state is observed in both CePt{sub 0.9}Au{sub 0.1}Zn and CePt{sub 0.9}Ni{sub 0.1}Zn with T{sub N}?=?2.1 and 1.1?K and the coefficient of the linear term of electronic heat capacity ??=?0.34 and 0.9?J/mol K{sup 2}, respectively. The corresponding values for CePtZn are 1.7?K and 0.6?J/mol K{sup 2}. The altered values of T{sub N} and ? show that the electronic correlations in CePtZn are affected by doping with Au and Ni. CeAuZn orders magnetically near 1.7?K and its electrical resistivity shows a normal metallic behavior. Together with a ? of 0.022?J/mol K{sup 2} the data indicate a weak 4f-conduction electron hybridization in CeAuZn characteristic of normal trivalent cerium based systems.

  11. Interpretation of the Phonon Frequency Shifts in ZnO Quantum Dots Khan A. Alim, Vladimir A. Fonoberov, and Alexander A. Balandin

    E-Print Network [OSTI]

    Fonoberov, Vladimir

    made of zinc oxide (ZnO), a wide-bandgap semiconductor, have recently attracted attention due Zinc oxide (ZnO) presents interesting material system because of its wide band gap of 3.37 eV and some ultraviolet (UV) protection films, gas sensors, and varistors. Raman spectroscopy presents a powerful tool

  12. Synthesis and characterization of one-dimensional flat ZnO nanotower arrays as high-efficiency adsorbents for the photocatalytic remediation of water

    E-Print Network [OSTI]

    pizeoelectronics,7,8 solar cells,9 UV-blocking components,10 photocatalysis,1113 and trans- parent conductive is an important goal for environmental control in industrial settings. Adsorption and chemical coagulation and thin film forms of ZnO have been explored to date for environmental applications.22,23 Powder-form Zn

  13. Polarization fields in (Zn,Cd)OZnO quantum well structures S. Kalusniak, S. Sadofev, J. Puls, H. J. Wnsche, and F. Henneberger*

    E-Print Network [OSTI]

    Wünsche, Hans-Jürgen "Ede"

    forced by the different crystalline structure of the binaries, wurtzite for ZnO and rocksalt for CdO. Epitaxial growth far from thermal equilibrium has made it possible to alloy ZnO with CdO in strict wurtzite direction of the QW structures is along the polar c axis of the wurtzite lattice. As a consequence, built

  14. Morphology-tuned wurtzite-type ZnS ZHONGWU WANG1*, LUKE L. DAEMEN1, YUSHENG ZHAO1, C. S. ZHA2, ROBERT T. DOWNS3,

    E-Print Network [OSTI]

    Wang, Zhong L.

    ARTICLES Morphology-tuned wurtzite-type ZnS nanobelts ZHONGWU WANG1*, LUKE L. DAEMEN1, YUSHENG ZHAO. The optical properties of the semiconductor ZnS in wurtzite structures are considerably enhanced, but the lack of structural stability limits technological applications. Here, we demonstrate that morphology-tuned wurtzite

  15. Effect of Synthesis Condition and Annealing on the Sensitivity and Stability of Gas Sensors Made of Zn-Doped y-Fe2O3 Particles

    E-Print Network [OSTI]

    Kim, Taeyang

    2010-10-12T23:59:59.000Z

    In this study, the effect of synthesis conditions and annealing process on the sensitivity and stability of gas sensors made of flame-synthesized Zn-doped ?-Fe2O3 particles was investigated. Zn-doped ?-Fe2O3 particles were synthesized by flame...

  16. JOURNAL DE PHYSIQUE Colloque Cl, supplkment au no 4, Tome 38, Auril 1977, page Cl-303 MULTILAYER SINTERING OF MnZn FERRITES

    E-Print Network [OSTI]

    Boyer, Edmond

    SINTERING OF MnZn FERRITES IN CONTROLLED ATMOSPHERE M. I. ALAM, N. R. NAlR and T. V. RAMAMURTI Central dans la litterature que I'empilement depots de ferrites les uns sur les autres durant le traitement production des couches multiples d'echantillons de ferrite de Mn-Zn. On a utilise jusqu'a 10 couches d

  17. Effect of Synthesis Condition and Annealing on the Sensitivity and Stability of Gas Sensors Made of Zn-Doped y-Fe2O3 Particles

    E-Print Network [OSTI]

    Kim, Taeyang

    2010-10-12T23:59:59.000Z

    In this study, the effect of synthesis conditions and annealing process on the sensitivity and stability of gas sensors made of flame-synthesized Zn-doped ?-Fe2O3 particles was investigated. Zn-doped ?-Fe2O3 particles were synthesized by flame...

  18. A Highly Efficient Solar Cell Made from a Dye-Modified ZnO-Covered TiO2 Nanoporous Electrode

    E-Print Network [OSTI]

    Huang, Yanyi

    -circuit photovoltage. Introduction Overall power conversion efficiency1,2 reaching 10% for dye sensitized solar cellA Highly Efficient Solar Cell Made from a Dye-Modified ZnO-Covered TiO2 Nanoporous Electrode Zhong A photoelectrochemical solar cell based on porous ZnO-covered TiO2 film has been fabricated with ruthenium bipyridyl

  19. The 3-stage evolution of the Angouran Zn "oxide"-sulfide deposit, Iran Fakultt Chemie, Technische Universitt Mnchen, Germany albert.gilg@geo.tum.de

    E-Print Network [OSTI]

    Boni, Maria

    The 3-stage evolution of the Angouran Zn "oxide"-sulfide deposit, Iran H.A. Gilg Fakultät Chemie@unina.it F. Moore Geological Department, University Shiraz, Iran moor@geology.susc.ac.ir Keywords: Angouran, Iran, sulfide, MVT, smithsonite, hypogene, supergene ABSTRACT: The giant Angouran Zn-Pb deposit (Zanjan

  20. Al-doped ZnO inverse opal networks as efficient electron collectors in BiVO4 photoanodes for solar

    E-Print Network [OSTI]

    Steiner, Ullrich

    Al-doped ZnO inverse opal networks as efficient electron collectors in BiVO4 photoanodes for solar-doped ZnO inverse opal network is introduced into a BiVO4 photoanode. The conductive inverse opal network of photogenerated charge carriers limits the performance of photoelectrodes for solar water splitting. To reduce

  1. Structural characterization and novel optical properties of defect chalcopyrite ZnGa{sub 2}Te{sub 4} thin films

    SciTech Connect (OSTI)

    Fouad, S.S., E-mail: icgegypt@link.net [Department of Physics, Faculty of Education, Ain Shams University, Cairo (Egypt); Sakr, G.B., E-mail: gamalsaker@yahoo.com [Department of Physics, Faculty of Education, Ain Shams University, Cairo (Egypt); Yahia, I.S., E-mail: dr_isyahia@yahoo.com [Department of Physics, Faculty of Education, Ain Shams University, Cairo (Egypt); Basset, D.M. Abdel, E-mail: dalia.physics@gmail.com [Department of Physics, Faculty of Education, Ain Shams University, Cairo (Egypt)] [Department of Physics, Faculty of Education, Ain Shams University, Cairo (Egypt)

    2011-11-15T23:59:59.000Z

    Highlights: {yields} Preparation and characterization of ZnGa{sub 2}Te{sub 4} in powder and thin film forms. {yields} Structure properties such as XRD and EDX. {yields} Optical constant of the as-deposited ZnGa{sub 2}Te{sub 4} for the first time. {yields} Extraction of the optical parameters of the studied films. -- Abstract: Stoichiometric thin film samples of the ternary ZnGa{sub 2}Te{sub 4} defect chalcopyrite compound were prepared and characterized by X-ray diffraction technique. The elemental chemical composition of the prepared bulk material as well as of the as-deposited film was determined by energy-dispersive X-ray spectrometry. ZnGa{sub 2}Te{sub 4} thin films were deposited, by conventional thermal evaporation technique onto highly cleaned glass substrates. The X-ray and electron diffraction studies revealed that the as-deposited and the annealed ZnGa{sub 2}Te{sub 4} films at annealing temperature t{sub a} {<=} 548 K are amorphous, while those annealed at t{sub a} {>=} 573 K (for 1 h), are polycrystalline. The optical properties of the as-deposited films have been investigated for the first time at normal incidence in the spectral range from 500 to 2500 nm. The refractive index dispersion in the transmission and low absorption region is adequately described by the Wemple-DiDomenico single oscillator model, whereby, the values of the oscillator parameters have been calculated. The analysis of the optical absorption coefficient revealed an in-direct optical transition with energy of 1.33 eV for the as-deposited sample. This work suggested that ZnGa{sub 2}Te{sub 4} is a good candidate in solar cell devices as an absorbing layer.

  2. Carbonaceous spheresan unusual template for solid metal oxide mesoscale spheres: Application to ZnO spheres

    SciTech Connect (OSTI)

    Patrinoiu, Greta; Caldern-Moreno, Jose Maria; Culita, Daniela C. [Illie Murgulescu Institute of Physical Chemistry, Romanian Academy, Splaiul Independentei 202, 060021 Bucharest (Romania); Birjega, Ruxandra [National Institute for Lasers, Plasma and Radiation Physics, P.O. Box Mg27, Magurele, Bucharest (Romania); Ene, Ramona [Ilie Murgulescu Institute of Physical Chemistry, Romanian Academy, Splaiul Independentei 202, 060021 Bucharest (Romania); Carp, Oana, E-mail: ocarp@icf.ro [Ilie Murgulescu Institute of Physical Chemistry, Romanian Academy, Splaiul Independentei 202, 060021 Bucharest (Romania)

    2013-06-15T23:59:59.000Z

    A green template route for the synthesis of mesoscale solid ZnO spheres was ascertained. The protocol involves a double coating of the carbonaceous spheres with successive layers of zinc-containing species by alternating a non-ultrasound and ultrasound-assisted deposition, followed by calcination treatments. The composites were characterized by FTIR spectroscopy, thermal analysis, scanning electron microscopy while the obtained ZnO spheres by X-ray diffraction, Raman spectroscopy, scanning and transmission electron microscopy, N{sub 2} adsorptiondesorption isotherms and photoluminescence investigations. A growth mechanism of the solid spheres is advanced based on these results. While the spheres' diameters and the mean size values of ZnO are independent on deposition order, the surface area and the external porosity are fairly dependent. The photoluminescence measurements showed interesting emission features, with emission bands in the violet to orange region. The spheres present high photocatalytical activity towards the degradation of phenol under UV irradiation, the main reaction being its mineralization. - Graphical abstract: A novel and eco-friendly methodology for the synthesis of mesoscale solid ZnO spheres was developed. The protocol involves a double coating of the starch-derived carbonaceous spheres with successive layers of zinc-containing species by alternating a non-ultrasound and ultrasound-assisted deposition, followed by calcination treatments. - Highlights: ZnO solid spheres are obtained via a template route using carbonaceous spheres. Two-step coatings of interchangeable order are used as deposition procedure. The coating procedure influences the porosity and surface area. ZnO spheres exhibited interesting visible photoluminescence properties. Solid spheres showed photocatalytical activity in degradation of phenol.

  3. Enhancement of surface phonon modes in the Raman spectrum of ZnSe nanoparticles on adsorption of 4-mercaptopyridine

    SciTech Connect (OSTI)

    Islam, Syed K.; Lombardi, John R. [Department of Chemistry, The City College of New York, New York, New York 10031 (United States)] [Department of Chemistry, The City College of New York, New York, New York 10031 (United States)

    2014-02-21T23:59:59.000Z

    By chemically etching a thin film of crystalline ZnSe with acid, we observe a strong Raman enhancement of the surface phonon modes of ZnSe on adsorption of a molecule (4-mercaptopyridine). The surface is composed of oblate hemi-ellipsoids, which has a large surface-to-bulk ratio. The assignment of the observed modes (at 248 and 492 cm{sup ?1}) to a fundamental and first overtone of the surface optical mode is consistent with observations from high-resolution electron energy loss spectroscopy as well as calculations.

  4. Interface as the origin of ferromagnetism in cobalt doped ZnO film grown on silicon substrate

    SciTech Connect (OSTI)

    Yin, Z. G.; Chen, N. F.; Zhang, X. W.; Bai, Y. M.; Chai, C. L. [Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Li, Y. [Department of Engineering Science and Materials, University of Puerto Rico at Mayaguez, Mayaguez 00681-9044 (Puerto Rico); Xie, Y. N.; Zhang, J. [Laboratory of Synchrotron Radiation, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100039 (China)

    2008-10-06T23:59:59.000Z

    We have investigated the magnetic properties of Co-doped zinc oxide (ZnO) film deposited on silicon substrate by magnetron sputtering. Co ions have a valence of 2+ and substitute for Zn sites in the lattice. By using a chemical etching method, an extrinsic ferromagnetism was demonstrated. The observed ferromagnetism is neither associated with magnetic precipitates nor with contamination, but originates from the silicon/silicon oxide interface. This interface ferromagnetism is characterized by being temperature independent and by having a parallel magnetic anisotropy.

  5. Search for double beta decay of Zinc and Tungsten with the help of low-background ZnWO4 crystal scintillators

    E-Print Network [OSTI]

    P. Belli; R. Bernabei; F. Cappella; R. Cerulli; F. A. Danevich; B. V. Grinyov; A. Incicchitti; V. V. Kobychev; V. M. Mokina; S. S. Nagorny; L. L. Nagornaya; S. Nisi; F. Nozzoli; D. V. Poda; D. Prosperi; V. I. Tretyak; S. S. Yurchenko

    2008-11-14T23:59:59.000Z

    Double beta processes in 64-Zn, 70-Zn, 180-W, and 186-W have been searched for with the help of large volume (0.1-0.7 kg) low background ZnWO4 crystal scintillators at the Gran Sasso National Laboratories of the INFN. Total time of measurements exceeds 10 thousands hours. New improved half-life limits on double electron capture and electron capture with positron emission in 64-Zn have been set, in particular (all the limits are at 90% C.L.): T1/2(0nu2EC)> 1.1e20 yr, T1/2(2nuECbeta+)>7.0e20 yr, and T1/2(0nuECbeta+)>4.3e20 yr. The different modes of double beta processes in 70-Zn, 180-W, and 186-W have been restricted at the level of 1e17-1e20 yr.

  6. In-situ study of discontinuous precipitation in Al-15 at.% Zn

    SciTech Connect (OSTI)

    Abdou, S.; El-Boragy, M. [Suez Canal Univ., Port Said (Egypt). Faculty of Engineering] [Suez Canal Univ., Port Said (Egypt). Faculty of Engineering; Solorzano, G. [PUC-RJ, Rio de Janeiro (Brazil). Dept. of Metallurgy and Materials Science] [PUC-RJ, Rio de Janeiro (Brazil). Dept. of Metallurgy and Materials Science; Gust, W.; Predel, B. [Max-Planck-Institut fuer Metallforschung, Stuttgart (Germany)] [Max-Planck-Institut fuer Metallforschung, Stuttgart (Germany); [Institut fuer Metallkunde der Universitaet, Stuttgart (Germany)

    1996-05-01T23:59:59.000Z

    In the present study, attention was focused on in-situ work on discontinuous precipitation in Al-15.0 at.% Zn in a high voltage electron microscope using a hot stage and a video system. The microscope was an AEI instrument with a maximum voltage of 1.25 MV. The voltage used was 500 kV. The scope of the present study was to check if the grain boundary migration in the discontinuous precipitation reaction proceeds in a stop-and-go fashion. From all the observations reported here it can be concluded that the stop-and-go type of grain boundary migration seems to be a very general one. But in many cases it cannot easily experimentally be proved. In case of discontinuous precipitation in Al-15.0 at.% Zn it has been clearly demonstrated by in-situ observations in a high-voltage electron microscope that the reaction front migration occurs in a stop-and-go fashion. Consequently, there is a drastic difference between the average velocity and the instantaneous velocity. The only quantity, which can be determined in traditional experiments, is the average velocity to which the Petermann-Hornbogen equation is adequate.

  7. Enriched Zn$^{100}$MoO$_4$ scintillating bolometers to search for $0 \

    E-Print Network [OSTI]

    Barabash, A S; Danevich, F A; Giuliani, A; Ivanov, I M; Makarov, E P; Mancuso, M; Marnieros, S; Nasonov, S G; Nones, C; Olivieri, E; Pessina, G; Poda, D V; Shlegel, V N; Tenconi, M; Tretyak, V I; Vasiliev, Ya V; Velazquez, M; Zhdankov, V N

    2014-01-01T23:59:59.000Z

    The LUMINEU project aims at performing a demonstrator underground experiment searching for the neutrinoless double beta decay of the isotope $^{100}$Mo embedded in zinc molybdate (ZnMoO$_4$) scintillating bolometers. In this context, a zinc molybdate crystal boule enriched in $^{100}$Mo to 99.5\\% with a mass of 171 g was grown for the first time by the low-thermal-gradient Czochralski technique. The production cycle provided a high yield (the crystal boule mass was 84\\% of initial charge) and an acceptable level -- around 4\\% -- of irrecoverable losses of the costy enriched material. Two crystals of 59 g and 63 g, obtained from the enriched boule, were tested aboveground at milli-Kelvin temperature as scintillating bolometers. They showed a high detection performance, equivalent to that of previously developed natural ZnMoO$_4$ detectors. These results pave the way to future sensitive searches based on the LUMINEU technology, capable to approach and explore the inverted hierarchy region of the neutrino mass p...

  8. Remarkable Thermal Stability of Amorphous In-Zn-O Transparent Conductors

    SciTech Connect (OSTI)

    Taylor, M. P.; Readey, D. W.; van Hest, M. F. A. M.; Teplin, C. W.; Alleman, J. L.; Dabney, M. S.; Gedvilas, L. M.; Keyes, B. M.; To, B.; Perkins, J. D.; Ginley, D. S.

    2008-10-01T23:59:59.000Z

    Transparent conducting oxides (TCOs) are increasingly critical components in photovoltaic cells, low-e windows, flat panel displays, electrochromic devices, and flexible electronics. The conventional TCOs, such as Sn-doped In{sub 2}O{sub 3}, are crystalline single phase materials. Here, we report on In-Zn-O (IZO), a compositionally tunable amorphous TCO with some significantly improved properties. Compositionally graded thin film samples were deposited by co-sputtering from separate In{sub 2}O{sub 3} and ZnO targets onto glass substrates at 100 C. For the metals composition range of 55-84 cation% indium, the as-deposited IZO thin films are amorphous, smooth (R{sub RMS} < 0.4 nm), conductive ({sigma} {approx} 3000 {Omega}{sup -1} {center_dot} cm{sup -1}), and transparent in the visible (T{sub Vis} > 90%). Furthermore, the amorphous IZO thin films demonstrate remarkable functional and structural stability with respect to heating up to 600 C in either air or argon. Hence, though not completely understood at present, these amorphous materials constitute a new class of fundamentally interesting and technologically important high performance transparent conductors.

  9. Exciton trapping in vibrationally excited organic molecules near a ZnO surface

    E-Print Network [OSTI]

    Foglia, Laura; Wolf, Martin; Sthler, Julia

    2014-01-01T23:59:59.000Z

    We present a systematic study of the exciton population dynamics at the interface of the spirobifluorene derivative 2,7-bis(biphenyl-4-yl)-2',7'-ditertbutyl-9.9'-spirobifluorene (SP6) and the non-polar (10-10) surface of ZnO, using time-resolved excited state optical transmission spectroscopy. The photoexcited dye first undergoes intramolecular vibrational relaxation in the S1 state on a 2 to 9 ps timescale. Subsequently, the excited state transmission reveals transitions from two distinct vibrational levels of S1, with a lifetime of the vibrationally excited state that is comparable to the one of the vibrational ground state (vGS). The electronic population relaxes by (i) decay to the electronic ground state (ii) transfer to a long-lived dark state that remains populated for longer than 5 microseconds, and (iii) diffusion-limited charge transfer to the ZnO conduction band. Remarkably, the lifetime of the vibratioanlly trapped excition (exciton-vibron) and vGS exciton are not equally affected by a change of s...

  10. Effects of Ti substitution on structural and magnetic properties of ZnMn ferrospinels

    SciTech Connect (OSTI)

    Patil, R.P., E-mail: raj_rbm_raj@yahoo.com [Department of Chemistry, Shivaji University, Kolhapur 416004 (India); Patil, N.M. [Department of Chemistry, Shivaji University, Kolhapur 416004 (India); Sasikala, R. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Hankare, P.P., E-mail: p_hankarep@rediffmail.com [Department of Chemistry, Shivaji University, Kolhapur 416004 (India); Delekar, S.D. [Department of Chemistry, Dr. Babasaheb Ambedkar Marathwada University, Sub-campus Osmanabad, 413501 (India)

    2013-05-15T23:59:59.000Z

    Highlights: ? Novel system ZnMn{sub 1?x}Ti{sub x}FeO{sub 4} synthesized by solgel route. ? Nanocrystalline materials. ? Magnetic materials. - Abstract: Nanocrystalline ZnMn{sub 1?x}Ti{sub x}FeO{sub 4} (1.0 ? x ? 0) ferrites were prepared by solgel route. Formation of single phase cubic spinel structure for all the compositions was confirmed from their X-ray diffraction patterns. The lattice parameter shows an increasing trend with the increase in Ti content. These ferrite samples existed as crystalline nanoparticles of about 3040 nm size as observed from transmission electron microscopy (TEM) technique. EDAX analysis indicated that the concentration of different elements in different compositions is in close agreement with the starting concentrations. Infrared spectra showed two main absorption bands in the range 400800 cm{sup ?1} arising due to tetrahedral (A) and octahedral (B) stretching vibrations. The magnetic studies indicated that, the ferrimagnetic behavior increases with titanium substitution.

  11. SeZnSb alloy and its nano tubes, graphene composites properties

    SciTech Connect (OSTI)

    Singh, Abhay Kumar [Department of Physics, Indian Institute of Physics, Bangalore-560012 (India)

    2013-04-15T23:59:59.000Z

    Composite can alter the individual element physical property, could be useful to define the specific use of the material. Therefore, work demonstrates the synthesis of a new composition Se{sub 96}-Zn{sub 2}-Sb{sub 2} and its composites with 0.05% multi-walled carbon nano tubes and 0.05% bilayer graphene, in the glassy form. The diffused amorphous structure of the multi walled carbon nano tubes and bilayer gaphene in the Se{sub 96}-Zn{sub 2}-Sb{sub 2} alloy have been analyzed by using the Raman, X-ray photoluminescence spectroscopy, Furrier transmission infrared spectra, photoluminescence, UV/visible absorption spectroscopic measurements. The diffused prime Raman bands (G and D) have been appeared for the multi walled carbon nano tubes and graphene composites, while the X-ray photoluminescence core energy levels peak shifts have been observed for the composite materials. Subsequently the photoluminescence property at room temperature and a drastic enhancement (upto 80%) in infrared transmission percentage has been obtained for the bilayer graphene composite, along with optical energy band gaps for these materials have been evaluated 1.37, 1.39 and 1.41 eV.

  12. A single-molecule approach to ZnO defect studies: Single photons and single defects

    SciTech Connect (OSTI)

    Jungwirth, N. R.; Pai, Y. Y.; Chang, H. S.; MacQuarrie, E. R.; Nguyen, K. X.; Fuchs, G. D. [Cornell University, Ithaca, New York 14853 (United States)

    2014-07-28T23:59:59.000Z

    Investigations that probe defects one at a time offer a unique opportunity to observe properties and dynamics that are washed out of ensemble measurements. Here, we present confocal fluorescence measurements of individual defects in ZnO nanoparticles and sputtered films that are excited with sub-bandgap energy light. Photon correlation measurements yield both antibunching and bunching, indicative of single-photon emission from isolated defects that possess a metastable shelving state. The single-photon emission is in the range of ?560720?nm and typically exhibits two broad spectral peaks separated by ?150?meV. The excited state lifetimes range from 1 to 13?ns, consistent with the finite-size and surface effects of nanoparticles and small grains. We also observe discrete jumps in the fluorescence intensity between a bright state and a dark state. The dwell times in each state are exponentially distributed and the average dwell time in the bright (dark) state does (may) depend on the power of the exciting laser. Taken together, our measurements demonstrate the utility of a single-molecule approach to semiconductor defect studies and highlight ZnO as a potential host material for single-defect based applications.

  13. A TbZn tetra(4-sulfonatophenyl)porphyrin hybrid: Preparation, structure, photophysical and electrochemical properties

    SciTech Connect (OSTI)

    Chen, Wen-Tong, E-mail: wtchen_2000@aliyun.com [Institute of Applied Chemistry, School of Chemistry and Chemical Engineering, Jiangxi Province Key Laboratory of Coordination Chemistry, Jinggangshan University, Ji'an 343009, Jiangxi (China); State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, Fujian (China); Hu, Rong-Hua; Wang, Yin-Feng; Zhang, Xian [Institute of Applied Chemistry, School of Chemistry and Chemical Engineering, Jiangxi Province Key Laboratory of Coordination Chemistry, Jinggangshan University, Ji'an 343009, Jiangxi (China); Liu, Juan [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, Fujian (China)

    2014-05-01T23:59:59.000Z

    A terbium-zinc porphyrin, i.e. [TbZn(TPPS)H{sub 3}O]{sub n} (1) (TPPS=tetra(4-sulfonatophenyl)porphyrin), has been obtained from a solvothermal reaction and structurally analyzed by single-crystal X-ray diffraction. Compound 1 is characteristic of a condensed three-dimensional (3-D) porous open framework with two types of infinite one-dimensional (1-D) chain-like structure. Compound 1 exhibits a void space of 215 ?{sup 3}, which is 9.2% of the unit-cell volume. TG/DTA measurement reveals that the framework of compound 1 is thermally stable up to 336 C. In order to reveal its photophysical and electrochemical properties, we investigated compound 1 in detail with UVvis spectra, fluorescence, quantum yield, luminescence lifetime, and CV/DPV. - Graphical abstract: A terbiumzinc porphyrin [TbZn(TPPS)H{sub 3}O]{sub n} has been obtained from a solvothermal reaction. It features a condensed 3-D porous open framework. It shows good thermal stability. - Highlights: This paper reports a novel terbiumzinc porphyrin. It features a novel condensed three-dimensional porous open framework. The title compound is thermally stable up to 336 C. It is studied by UVvis, fluorescence, quantum yield, lifetime, and CV/DPV.

  14. Nuclear data relevant to the production of {sup 67}Ga: A critical comparison of excitation functions/thick target yield data for {sup 67}Zn(p,n) and {sup 68}Zn(p,2n) nuclear reactions

    SciTech Connect (OSTI)

    Szelecsenyi, F.; Boothe, T.E.; Tavano, E.; Plitnikas, M. [Mount Sinai Medical Center, Miami Beach, FL (United States); Takacs, S.; Tarkanyi, F. [Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen (Hungary)

    1994-12-31T23:59:59.000Z

    The method of choice for routine production of {sup 67}Ga on a low energy cyclotron is the {sup 67}Zn(p,n){sup 67}Ga reaction while above 20 MeV the {sup 68}Zn(p,2n){sup 67}Ga process results in a higher yield of gallium. To optimize the yields in a production setting it is important to know the cross sections/thick target yield data of these reactions. In spite of the large amount of experimental information on cross section/thick target yield data of the desired reactions published up to 1993, the status in some cases is not satisfactory. In the present work, the authors have compared the available cross sections/thick target yield data and have tried to resolve the most obvious discrepancies which have appeared in the literature. The authors also present an evaluated data base for the mentioned data for the {sup 67}Zn(p,n){sup 67}Ga and {sup 68}Zn(p,2n){sup 67}Ga nuclear reactions.

  15. Investigation of site preference of Zn doped Ba{sub 3}Co{sub 2?x}Zn{sub x}Fe{sub 24}O{sub 41} by Mssbauer spectroscopy

    SciTech Connect (OSTI)

    Lim, Jung Tae; Kim, Chul Sung, E-mail: cskim@kookmin.ac.kr [Department of Physics, Kookmin University, Seoul 136-702 (Korea, Republic of)

    2014-05-07T23:59:59.000Z

    The polycrystalline Ba{sub 3}Co{sub 2?x}Zn{sub x}Fe{sub 24}O{sub 41} (x?=?0.0, 0.5, 1.0) samples were prepared by using solid-state-reaction method. The crystal structures and magnetic properties of samples were investigated with x-ray diffractometer, vibrating sample magnetometer, and Mssbauer spectroscopy. The crystal structure of Ba{sub 3}Co{sub 2?x}Zn{sub x}Fe{sub 24}O{sub 41} (x?=?0.0, 0.5, 1.0) samples was determined to be a hexagonal structure with P6{sub 3}/mmc space group at 295 K, and the saturation magnetization (M{sub s}) of Ba{sub 3}Co{sub 2?x}Zn{sub x}Fe{sub 24}O{sub 41} (x?=?0.0, 0.5, 1.0) samples were found to be M{sub s} =?50.9, 53.1, 55.0 emu/g, respectively. From the temperature dependence of magnetization curves under 100 Oe between 4.2 and 740?K, we were able to observe the spin transition, and both spin transition temperature (T{sub s}) and Curie temperature (T{sub C}) decrease with increasing Zn concentration. Mssbauer spectra of all samples were obtained and analyzed at various temperatures ranging from 4.2 to 295 K. With ten-sextets for Fe sites corresponding to the Z-type hexagonal crystallographic sites, all spectra below T{sub C} were fitted by least-square method. In addition, from the site occupation numbers of Fe, calculated from the relative areas fitted to the Mssbauer spectra, we find that Zn ions preferentially occupy the tetrahedral sublattices of down sites.

  16. Degradation of transparent conductive properties of undoped ZnO and Ga-doped ZnO films left in atmospheric ambient for several years and trials to recover initial conductance

    SciTech Connect (OSTI)

    Akazawa, Housei, E-mail: akazawa.housei@lab.ntt.co.jp [NTT Microsystem Integration Laboratories, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198 (Japan)

    2014-03-15T23:59:59.000Z

    This study evaluated the long-term stability of the transparent conductive properties of undoped ZnO and Ga-doped ZnO (GZO) films that had been left in an atmospheric ambient environment for 5 to 6 yr. When ZnO films are stored in a clean room with a controlled temperature and humidity of 23?C and 45%, respectively, throughout the year, the increases in sheet resistance are less than 5% of their initial value. The ZnO films stored in a non-air-conditioned laboratory room, whose temperature varies between 5 and 35?C and humidity varies between 30% and 70% per year, suffer from increases in the sheet resistance by almost 13%, which is associated with a slight rise in the near-infrared transmittance level. Postannealing of these degraded ZnO films at 150200?C recovers the initial conductance by removing the H{sub 2}O molecules that have penetrated the film. One hour of irradiation with electron cyclotron resonance Ar plasma effectively restores the conductive surfaces while maintaining a temperature below 70?C. The GZO films containing a few weight percent of Ga{sub 2}O{sub 3} are stable even when stored in a non-air-conditioned laboratory room, with changes in the sheet resistance of less than 3%. The GZO films with a Ga{sub 2}O{sub 3} content larger than 10?wt. %, however, exhibit serious degradation probably due to the strong affinity of segregated Ga{sub 2}O{sub 3} domains with H{sub 2}O vapor molecules. Neither postannealing nor Ar plasma irradiation can recover the initial sheet resistance of these GZO films.

  17. Structural characterization of ZnO films grown by molecular beam epitaxy on sapphire with MgO buffer

    SciTech Connect (OSTI)

    Pecz, B.; El-Shaer, A.; Bakin, A.; Mofor, A.-C.; Waag, A.; Stoemenos, J. [Research Institute for Technical Physics and Materials Science, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Institute of Semiconductor Technology, Technical University Braunschweig, Hans-Sommer-Strasse 66, D-38106 Braunschweig (Germany); Physics Department, Aristotle University, University Campus, 54006 Thessaloniki (Greece)

    2006-11-15T23:59:59.000Z

    The structural characteristics of the ZnO film grown on sapphire substrate using a thin MgO buffer layer were studied using transmission electron microscopy and high-resolution x-ray diffraction. The growth was carried out in a modified plasma-molecular beam epitaxy system. The observed misfit dislocations were well confined at the sapphire overgrown interface exhibiting domain matching epitaxy, where the integral multiples of lattice constants match across the interface. The main extended defects in the ZnO film were the threading dislocations having a mean density of 4x10{sup 9} cm{sup -2}. The formation of the MgO buffer layer as well as the ZnO growth were monitored in situ by reflection high-energy electron diffraction. The very thin {approx}1 nm, MgO buffer layer can partially interdiffuse with the ZnO as well as react with the Al{sub 2}O{sub 3} substrate forming an intermediate epitaxial layer having the spinel (MgO/Al{sub 2}O{sub 3}) structure.

  18. Highly efficient flexible inverted organic solar cells using atomic layer deposited ZnO as electron selective layer

    E-Print Network [OSTI]

    . Conventional OSCs generally consist of an acidic poly(3,4-ethyl- enedioxythiophene) : poly function metallic cathode which oxidizes easily in air. Therefore, these devices exhibit poor lifetimes.7 a PCE of 3.09%.14 Hau et al. adopted spin-coated ZnO nanoparticles as the electron selective layer

  19. drinking water. On the basis of the volume of ZnS precipitated in the biofilm, we estimate

    E-Print Network [OSTI]

    Kurapov, Alexander

    drinking water. On the basis of the volume of ZnS precipitated in the biofilm, we estimate, 647 (1964). 6. W. J. Drury, Water Environ. Res. 71, 1244 (1999). 7. U.S. Environmental Protection Agency, Office of Ground Water and Drinking Water, Current Drinking Water Standards (2000). 8

  20. Evidence for Native-Defect Donors in n-Type ZnO D. C. Look,1,2

    E-Print Network [OSTI]

    Nordlund, Kai

    , coupled with the theoretical evidence of high formation energies for the native donors [7], has ledEvidence for Native-Defect Donors in n-Type ZnO D. C. Look,1,2 G. C. Farlow,1 Pakpoom Reunchan,3, Wright-Patterson Air Force Base, Ohio 45433, USA 3 School of Physics, Suranaree University of Technology

  1. Mineralogical heterogeneities in the Earth's mantle: Constraints from Mn, Co, Ni and Zn partitioning during partial melting

    E-Print Network [OSTI]

    Lee, Cin-Ty Aeolus

    Mineralogical heterogeneities in the Earth's mantle: Constraints from Mn, Co, Ni and Zn online 1 June 2011 Editor: L. Stixrude Keywords: transition metals mineralogical heterogeneities are sensitive to changes in mineralogy or major element composition, and thus, are promising to trace

  2. Molecular beam epitaxy of n-type ZnS: A wide band gap emitter for heterojunction PV devices

    E-Print Network [OSTI]

    Atwater, Harry

    Molecular beam epitaxy of n-type ZnS: A wide band gap emitter for heterojunction PV devices Jeffrey and AZO transparent conductive oxides did not. Applications to novel PV devices incorporating low electron-ray diffraction, zinc compounds. I. INTRODUCTION The growing interest in scalable, thin-film photovoltaics (PV

  3. Metastability in Pressure-Induced Structural Transformations of CdSe/ZnS Core/Shell Nanocrystals

    E-Print Network [OSTI]

    Rabani, Eran

    . In nanocrystals with thick shells, we furthermore observe a wurtzite to NiAs transformation, which does not occur on particles' size and shape.2-6 The wurtzite to rocksalt transformation in CdSe nanocrystals, for example wurtzite CdSe nanocrystals of 3 nm diameter (500 atoms), that have been epitaxially passivated with Zn

  4. CHOPPING VERSUS GRINDING AND PELLETING OF HAY : EFFECT ON AVAILABILITY OF TRACE ELEMENTS (Cu, Zn and Mn)

    E-Print Network [OSTI]

    Boyer, Edmond

    CHOPPING VERSUS GRINDING AND PELLETING OF HAY : EFFECT ON AVAILABILITY OF TRACE ELEMENTS (Cu, Zn often receive ground diets that may or may not be pelleted. We intended to examine the effect of transit) chopped into pieces 3 cm long, or ground in a grinder equipped with a 0.6 mm sieve and pelleted in 6 mm

  5. SYNTHESIS AND SURFACE CHEMISTRY OF ZN3P2 Gregory M. Kimball, Nathan S. Lewis, Harry A. Atwater

    E-Print Network [OSTI]

    Kimball, Gregory

    alternative to traditional materials (e.g. CIGS, CdTe, a-Si) for thin film photovoltaics. Open circuit voltage in Zn3P2 cells has been limited by Fermi-level pinning due to surfaces states and heterojunction promise for solar energy conversion but has not been investigated as thoroughly as other thin film

  6. DISTORTIONS TO CURRENT-VOLTAGE CURVES OF CIGS CELLS WITH SPUTTERED Zn(O,S) BUFFER LAYERS

    E-Print Network [OSTI]

    Sites, James R.

    alternative to CdS for (CIGS) thin-film solar cells' buffer layer. It has a higher band gap and thus allows to current- voltage (J-V) curves of sputtered-Zn(O,S)/CIGS solar cells. A straightforward photodiode model partner in the CIGS team, and Russell for showing me the solar cells characterization, and John, Jen

  7. Formation of Crystalline Zn-Al Layered Double Hydroxide Precipitates on Alumina: The Role of Mineral Dissolution

    E-Print Network [OSTI]

    Sparks, Donald L.

    the sequestration of toxic metals such as nickel (Ni), zinc (Zn), and cobalt (Co) as layered double hydroxide (LDH, which is an important mechanism for toxic metal sequestration in natural environments, carbonate, or silicate.8-10 Even though it is clear that Me-Al LDHs can form in certain environments

  8. Microstructure, mechanical property and corrosion behaviors of interpenetrating C/Mg-Zn-Mn composite fabricated by suction casting

    E-Print Network [OSTI]

    Zheng, Yufeng

    bonding between Mg-Zn-Mn alloy and carbon scaffold was very well. The composite had an ultimate. Introduction Carbon, in all its forms, such as carbon nanotubes, carbon fabric, carbon-carbon composites, glassy carbon, pyrocarbons and diamond- like layers, is considered as a promising material for biomedical

  9. Biologically programmed synthesis of core-shell CdSe/ZnS nanocrystalsw Shailendra Singh,ab

    E-Print Network [OSTI]

    Chen, Wilfred

    not only directs the nucleation of inorganic materials, but also controls the crystal structure and sizeBiologically programmed synthesis of core-shell CdSe/ZnS nanocrystalsw Shailendra Singh report of core-shell semiconductor nanocrystal synthesis using a peptide template. Type II

  10. Fermi level stabilization and band edge energies in Cd{sub x}Zn{sub 1?x}O alloys

    SciTech Connect (OSTI)

    Detert, Douglas M.; Tom, Kyle B.; Dubon, Oscar D. [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Materials Science and Engineering, University of California, Berkeley, California 94720 (United States); Battaglia, Corsin; Javey, Ali [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720 (United States); Denlinger, Jonathan D. [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Lim, Sunnie H. N. [Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Anders, Andr [Accelerator and Fusion Research Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Yu, Kin M.; Walukiewicz, Wladek [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2014-06-21T23:59:59.000Z

    We have measured the band edge energies of Cd{sub x}Zn{sub 1?x}O thin films as a function of composition by three independent techniques: we determine the Fermi level stabilization energy by pinning the Fermi level with ion irradiation, measure the binding energy of valence band states and core levels by X-ray photoelectron spectroscopy, and probe shifts in the conduction band and valence band density of states using soft X-ray absorption and emission spectroscopy, respectively. The three techniques find consensus in explaining the origin of compositional trends in the optical-bandgap narrowing upon Cd incorporation in wurtzite ZnO and widening upon Zn incorporation in rocksalt CdO. The conduction band minimum is found to be stationary for both wurtzite and rocksalt alloys, and a significant upward rise of the valence band maximum accounts for the majority of these observed bandgap changes. Given these band alignments, alloy disorder scattering is found to play a negligible role in decreasing the electron mobility for all alloys. These band alignment details, combined with the unique optical and electrical properties of the two phase regimes, make CdZnO alloys attractive candidates for photoelectrochemical water splitting applications.

  11. Dynamics of charge transport and recombination in ZnO nanorod array dye-sensitized solar cells

    E-Print Network [OSTI]

    Dynamics of charge transport and recombination in ZnO nanorod array dye-sensitized solar cells Alex nanoparticles. Introduction Dye-Sensitized Solar Cells (DSSCs) comprise an increasingly attractive alternative photovoltaic technology.1,2 These photo- electrochemical cells use molecular dyes to sensitize high-area, wide

  12. ZnO Nanostructures for Dye-Sensitized Solar Cells By Qifeng Zhang,* Christopher S. Dandeneau, Xiaoyuan Zhou, and

    E-Print Network [OSTI]

    Cao, Guozhong

    ZnO Nanostructures for Dye-Sensitized Solar Cells By Qifeng Zhang,* Christopher S. Dandeneau-low cost (US$0.40 kWh?1 ).[1] To aim at further lowering the production costs, dye-sensitized solar cells, such as solar cells, fuel cells, and biofuels. However, although these alternative energy sources have been

  13. Quantifying oxygen diffusion in ZnO nanobelt Jin Liu, Puxian Gao, Wenjie Mai, Changshi Lao, and Zhong L. Wanga

    E-Print Network [OSTI]

    Wang, Zhong L.

    Quantifying oxygen diffusion in ZnO nanobelt Jin Liu, Puxian Gao, Wenjie Mai, Changshi Lao A method is presented for quantifying oxygen diffusion behavior in a nanodevice fabricated using individual for several days, oxygen in air diffused into the nanobelt and significantly changed the conductivity

  14. Development of ZnNiCd coatings by pulse electrodeposition process Prabhu Ganesan, Swaminatha P. Kumaraguru, Branko N. Popov

    E-Print Network [OSTI]

    Popov, Branko N.

    Development of ZnNiCd coatings by pulse electrodeposition process Prabhu Ganesan, Swaminatha P form 22 August 2006 Available online 6 October 2006 Abstract A pulse electrodeposition process. An increase in average current density resulted in a decrease in both nickel and cadmium content in the alloy

  15. Synthesis of Mixed Ceramic MgxZn1-xO Nanofibers via Mg2+ Using Sol-Gel Electrospinning

    E-Print Network [OSTI]

    Khan, Saad A.

    acetate (MgAc) and zinc acetate (ZnAc) with poly(vinyl alcohol) (PVA), electrospinning is performed and then as- spun nanofibers are calcined in an air atmosphere at 600 C for 3 h. As-spun and calcined are promising candidates for various usage, from batteries to solar cells and catalysts. Sol-gel electrospinning

  16. PHYSICAL REVIEW B 84, 035313 (2011) Bound excitons in ZnO: Structural defect complexes versus shallow impurity centers

    E-Print Network [OSTI]

    Nabben, Reinhard

    2011-01-01T23:59:59.000Z

    activation energy and localization energy of the excitons and cannot be described by an effective mass centers is visualized in contrast to the homogeneous distribution of shallow impurity centers toward the development of a large ZnO based market for light emitting devices. The main requirements

  17. High-efficiency micro-energy generation based on free-carrier-modulated ZnO:N piezoelectric thin films

    SciTech Connect (OSTI)

    Lee, Eunju; Park, Jaedon; Yim, Munhyuk; Jeong, Sangbeom; Yoon, Giwan, E-mail: gwyoon@kaist.ac.kr [Department of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

    2014-05-26T23:59:59.000Z

    The free-carrier-modulated ZnO:N thin film-based flexible nanogenerators (NZTF-FNGs) are proposed and experimentally demonstrated. The suggested flexible nanogenerators (FNGs) are fabricated using N-doped ZnO thin films (NZTFs) as their piezoelectric active elements, which are deposited by a radio frequency magnetron sputtering technique with an N{sub 2}O reactive gas as an in situ dopant source. Considerable numbers of N atoms are uniformly incorporated into NZTFs overall during their growth, which would enable them to significantly compensate the unintentional background free electron carriers both in the bulk and at the surface of ZnO thin films (ZTFs). This N-doping approach is found to remarkably enhance the performance of NZTF-FNGs, which shows output voltages that are almost two orders of magnitude higher than those of the conventionally grown ZnO thin film-based FNGs. This is believed to be a result of both substantial screening effect suppression in the ZTF bulk and more reliable Schottky barrier formation at the ZTF interfaces, which is all mainly caused by the N-compensatory doping process. Furthermore, the NZTF-FNGs fabricated are verified via charging tests to be suitable for micro-energy harvesting devices.

  18. Materials Science and Engineering B 138 (2007) 224227 Synthesis of single crystalline europium-doped ZnO nanowires

    E-Print Network [OSTI]

    Kim, Bongsoo

    2007-01-01T23:59:59.000Z

    Materials Science and Engineering B 138 (2007) 224227 Synthesis of single crystalline europium; ZnO; Europium doping; XPS 1. Introduction Synthesizing one-dimensional (1D) nanostructures in semi and studies of the luminescent properties of europium (Eu)-doped semicon- ductors in various morphologies

  19. Tuning of deep level emission in highly oriented electrodeposited ZnO nanorods by post growth annealing treatments

    SciTech Connect (OSTI)

    Simimol, A. [Nanomaterials Research Laboratory, Surface Engineering Division CSIR-National Aerospace Laboratories, Post Bag No. 1779, Bangalore 560017 (India); Department of Physics, National Institute of Technology, Calicut 673601 (India); Manikandanath, N. T.; Chowdhury, Prasanta; Barshilia, Harish C., E-mail: harish@nal.res.in [Nanomaterials Research Laboratory, Surface Engineering Division CSIR-National Aerospace Laboratories, Post Bag No. 1779, Bangalore 560017 (India); Anappara, Aji A. [Department of Physics, National Institute of Technology, Calicut 673601 (India)

    2014-08-21T23:59:59.000Z

    Highly dense and c-axis oriented zinc oxide (ZnO) nanorods with hexagonal wurtzite facets were deposited on fluorine doped tin oxide coated glass substrates by a simple and cost-effective electrodeposition method at low bath temperature (80?C). The as-grown samples were then annealed at various temperatures (T{sub A}?=?100500?C) in different environments (e.g., zinc, oxygen, air, and vacuum) to understand their photoluminescence (PL) behavior in the ultra-violet (UV) and the visible regions. The PL results revealed that the as-deposited ZnO nanorods consisted of oxygen vacancy (V{sub O}), zinc interstitial (Zn{sub i}), and oxygen interstitial (O{sub i}) defects and these can be reduced significantly by annealing in different environments at optimal annealing temperatures. However, the intensity of deep level emission increased for T{sub A} greater than the optimized values for the respective environments due to the introduction of various defect centers. For example, for T{sub A}???450?C in the oxygen and air environments, the density of O{sub i} defects increased, whereas, the green emission associated with V{sub O} is dominant in the vacuum annealed (T{sub A}?=?500?C) ZnO nanorods. The UV peak red shifted after the post-growth annealing treatments in all the environments and the vacuum annealed sample exhibited highest UV peak intensity. The observations from the PL data are supported by the micro-Raman spectroscopy. The present study gives new insight into the origin of different defects that exist in the electrodeposited ZnO nanorods and how these defects can be precisely controlled in order to get the desired emissions for the opto-electronic applications.

  20. Co-assembly of Zn(SPh){sub 2} and organic linkers into helical and zig-zag polymer chains

    SciTech Connect (OSTI)

    Liu Yi; Yu Lingmin; Loo, Say Chye Joachim [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Blair, Richard G. [Chemistry and Forensic Science, University of Central Florida, Department of Chemistry, 4000 Central Florida Blvd. P.O. Box 162366, Orlando, FL 32816-2366 (United States); Zhang Qichun, E-mail: qczhang@ntu.edu.sg [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore)

    2012-07-15T23:59:59.000Z

    Two novel one-dimensional coordination polymers, single helicate [Zn(SPh){sub 2}(TPyTA)(EG)]{sub n} (EG=ethylene glycol) (1) and zig-zag structure [Zn(SPh){sub 2}(BPyVB)]{sub n} (2), were synthesized under solvothermal conditions at 150 Degree-Sign C or room temperature by the co-assembly of Zn(SPh){sub 2} and organic linkers such as 2,4,6-tri(4-pyridyl)-1,3,5-triazine (TPyTA) and 1,3-bis(trans-4-pyridylvinyl)benzene (BPyVB). X-ray crystallography study reveals that both polymers 1 and 2 crystallize in space group P2{sub 1}/c of the monoclinic system. The solid-state UV-vis absorption spectra show that 1 and 2 have maxium absorption onsets at 400 nm and 420 nm, respectively. TGA analysis indicates that 1 and 2 are stable up to 110 Degree-Sign C and 210 Degree-Sign C. - Graphical abstract: Two novel one-dimensional coordination polymers, single helicate [Zn(SPh){sub 2}(TPyTA)(EG)]{sub n} (1) and zig-zag structure [Zn(SPh){sub 2}(BPyVB)]{sub n} (2), were synthesized. Solid-state UV-vis absorptions show that 1 and 2 have maxium absorption onsets at 400 nm and 420 nm, respectively. TGA analysis indicates that 1 and 2 are stable up to 110 Degree-Sign C and 210 Degree-Sign C. Highlights: Black-Right-Pointing-Pointer Two novel one-dimensional coordination polymers have been synthesized. Black-Right-Pointing-Pointer TPyTA results in helical structures in 1 while BPyVB leads to zig-zag chains in 2. Black-Right-Pointing-Pointer Solid-state UV-vis absorption spectra and TGA analysis of the title polymers were studied.

  1. Hydrogen passivation of electron trap in amorphous In-Ga-Zn-O thin-film transistors

    SciTech Connect (OSTI)

    Hanyu, Yuichiro, E-mail: y-hanyu@lucid.msl.titech.ac.jp; Domen, Kay [Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama (Japan)] [Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama (Japan); Nomura, Kenji [Frontier Research Center, Tokyo Institute of Technology, Yokohama (Japan)] [Frontier Research Center, Tokyo Institute of Technology, Yokohama (Japan); Hiramatsu, Hidenori; Kamiya, Toshio [Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama (Japan) [Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama (Japan); Materials Research Center for Element Strategy, Tokyo Institute of Technology, Yokohama (Japan); Kumomi, Hideya [Materials Research Center for Element Strategy, Tokyo Institute of Technology, Yokohama (Japan)] [Materials Research Center for Element Strategy, Tokyo Institute of Technology, Yokohama (Japan); Hosono, Hideo [Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama (Japan) [Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama (Japan); Frontier Research Center, Tokyo Institute of Technology, Yokohama (Japan); Materials Research Center for Element Strategy, Tokyo Institute of Technology, Yokohama (Japan)

    2013-11-11T23:59:59.000Z

    We report an experimental evidence that some hydrogens passivate electron traps in an amorphous oxide semiconductor, a-In-Ga-Zn-O (a-IGZO). The a-IGZO thin-film transistors (TFTs) annealed at 300?C exhibit good operation characteristics; while those annealed at ?400?C show deteriorated ones. Thermal desorption spectra (TDS) of H{sub 2}O indicate that this threshold annealing temperature corresponds to depletion of H{sub 2}O desorption from the a-IGZO layer. Hydrogen re-doping by wet oxygen annealing recovers the good TFT characteristic. The hydrogens responsible for this passivation have specific binding energies corresponding to the desorption temperatures of 300430?C. A plausible structural model is suggested.

  2. A process for the chemical preparation of high-field ZnO varistors

    DOE Patents [OSTI]

    Brooks, R.A.; Dosch, R.G.; Tuttle, B.A.

    1986-02-19T23:59:59.000Z

    Chemical preparation techniques involving co-precipitation of metals are used to provide microstructural characteristics necessary in order to produce ZnO varistors and their precursors for high field applications. The varistors produced have homogeneous and/or uniform dopant distributions and a submicron average grain size with a narrow size distribution. Precursor powders are prepared via chemical precipitation techniques and varistors made by sintering uniaxially and/or isostatically pressed pellets. Using these methods, varistors were made which were suitable for high-power applications, having values of breakdown field, E/sub B/, in the 10 to 100 kV/cm range, ..cap alpha.. > 30 and densities in the range of 65 to 99% of theoretical, depending on both composition and sintering temperature.

  3. Crucial role of implanted atoms on dynamic defect annealing in ZnO

    SciTech Connect (OSTI)

    Azarov, A. Yu.; Kuznetsov, A. Yu.; Svensson, B. G. [Department of Physics, Centre for Materials Science and Nanotechnology, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo (Norway); Wendler, E. [Friedrich-Schiller-Universitt Jena, Institut fr Festkrperphysik, Max-Wien-Platz 1, 07743 Jena (Germany)

    2014-02-03T23:59:59.000Z

    Processes of defect formation in radiation hard semiconductors exhibiting efficient dynamic annealing are different from those in amorphizible ones, and the latter are generally more well-studied. In the present work, we investigate structural disorder in wurtzite ZnO, which is a radiation hard material, implanted with different ions at room temperature and 15?K. The sample analysis was undertaken by Rutherford backscattering/channeling spectrometry performed in-situ without changing the sample temperature. The fluence dependence of bulk disorder exhibits the so-called IV-stage evolution, where the high fluence regime is characterized by both a strong influence on the damage build-up by the ion type and a reverse temperature effect. A straightforward methodology is demonstrated to differentiate between the contributions of pure ballistic and ion-defect reaction processes in the damage formation.

  4. Enhanced stimulated emission in ZnO thin films using microdisk top-down structuring

    SciTech Connect (OSTI)

    Nomenyo, K.; Kostcheev, S.; Lrondel, G. [Laboratoire de Nanotechnologie et d'Instrumentation Optique, Institut Charles Delaunay, CNRS UMR 6281, Universit de Technologie de Troyes, 12 rue Marie Curie, CS 42060, 10004 Troyes Cedex (France); Gadallah, A.-S. [Laboratoire de Nanotechnologie et d'Instrumentation Optique, Institut Charles Delaunay, CNRS UMR 6281, Universit de Technologie de Troyes, 12 rue Marie Curie, CS 42060, 10004 Troyes Cedex (France); Department of Laser Sciences and Interactions, National Institute of Laser Enhanced Sciences, Cairo University, Giza (Egypt); Rogers, D. J. [Nanovation, 8, route de Chevreuse, 78117 Chteaufort (France)

    2014-05-05T23:59:59.000Z

    Microdisks were fabricated in zinc oxide (ZnO) thin films using a top-down approach combining electron beam lithography and reactive ion etching. These microdisk structured thin films exhibit a stimulated surface emission between 3 and 7 times higher than that from a reference film depending on the excitation power density. Emission peak narrowing, reduction in lasing threshold and blue-shifting of the emission wavelength were observed along with enhancement in the emitted intensity. Results indicate that this enhancement is due to an increase in the internal quantum efficiency combined with an amplification of the stimulated emission. An analysis in terms of waveguiding is presented in order to explain these effects. These results demonstrate that very significant gains in emission can be obtained through conventional microstructuration without the need for more onerous top-down nanostructuration techniques.

  5. Polariton lasing in a ZnO microwire above 450?K

    SciTech Connect (OSTI)

    Xu, Dan; Xie, Wei; Liu, Wenhui; Wang, Jian; Zhang, Long; Wang, Yinglei; Zhang, Saifeng; Sun, Liaoxin; Shen, Xuechu; Chen, Zhanghai, E-mail: zhanghai@fudan.edu.cn [State Key Laboratory of Surface Physics, Department of Physics and Laboratory of Advanced Materials, Fudan University, Shanghai 200433 (China)

    2014-02-24T23:59:59.000Z

    Exciton-polariton lasing in a one-dimensional ZnO microcavity is demonstrated at high temperature of 455?K. The massive occupation of the polariton ground state above a distinct pump power threshold is clearly demonstrated by using the angular resolved spectroscopy under non-resonant excitation. The temperature dependence of the polariton lasing threshold is well interpreted by two competing mechanisms, i.e., the thermodynamic and kinetic mechanisms. Michelson interference measurements are performed to investigate the temporal and spatial coherence of polariton laser, with the coherence time and coherence length being ?{sub c}?0.97?ps and r{sub c}?0.72?m at 440?K and 400?K, respectively.

  6. H TO Zn IONIZATION EQUILIBRIUM FOR THE NON-MAXWELLIAN ELECTRON {kappa}-DISTRIBUTIONS: UPDATED CALCULATIONS

    SciTech Connect (OSTI)

    Dzifcakova, E. [Astronomical Institute of the Academy of Sciences of the Czech Republic, Fricova 298, 251 65 Ondrejov (Czech Republic)] [Astronomical Institute of the Academy of Sciences of the Czech Republic, Fricova 298, 251 65 Ondrejov (Czech Republic); Dudik, J., E-mail: elena@asu.cas.cz [DAMTP, CMS, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)

    2013-05-01T23:59:59.000Z

    New data for the calculation of ionization and recombination rates have been published in the past few years, most of which are included in the CHIANTI database. We used these data to calculate collisional ionization and recombination rates for the non-Maxwellian {kappa}-distributions with an enhanced number of particles in the high-energy tail, which have been detected in the solar transition region and the solar wind. Ionization equilibria for elements H to Zn are derived. The {kappa}-distributions significantly influence both the ionization and recombination rates and widen the ion abundance peaks. In comparison with the Maxwellian distribution, the ion abundance peaks can also be shifted to lower or higher temperatures. The updated ionization equilibrium calculations result in large changes for several ions, notably Fe VIII-Fe XIV. The results are supplied in electronic form compatible with the CHIANTI database.

  7. Effect of ultrasonic treatment on tensile properties of PLA/LNR/NiZn ferrite nanocomposite

    SciTech Connect (OSTI)

    Shahdan, Dalila; Ahmad, Sahrim Hj.; Flaifel, Moayad Husein [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

    2013-11-27T23:59:59.000Z

    The influence of sonication treatment time on the morphological and mechanical properties of LNR/PLA composite impregnated with different filler loadings of NiZn ferrite nanoparticles was investigated. The nanocomposite was prepared using melt blending method with assistance of ultrasonic treatment of 0, 1 and 2 hrs. Structural characterization of the nanocomposites was examined using scanning electron microscopy (SEM) with their elemental composition being confirmed by energy dispersive X-ray spectroscopy (EDX). The tensile properties of LNR/PLA composite treated with different ultrasonication times have improved with increasing magnetic nanofiller signature in the nanocomposite. Further, the optimum sonication time of 1 hr was found to produce nanocomposite with maximum tensile properties.

  8. Role of sonic energy on growth morphology and optical properties of ZnO:S nanostructures

    SciTech Connect (OSTI)

    Panda, Nihar Ranjan, E-mail: niharphysics@yahoo.co.in; Nayak, Pratibindhya [School of Physics, Sambalpur University, Jyoti Vihar, Burla-768019, Odisha (India); Acharya, Bhabani Shankar [C.V. Raman College of Engineering, Bhubaneswar-752054, Odisha (India)

    2014-04-24T23:59:59.000Z

    ZnO nanopowders doped with sulphur were prepared by sonochemical method. The input power of ultrasound was varied as 40%, 50% and 60% of the maximum power (375 W) in both continuous and pulsed mode. XRD results show the average size of the nanoparticles is the least for those prepared with 50% input power as well as the micro-strain. FESEM studies showed the formation of nanorods clubbed together to form flower like structure for these samples. In rest of the cases, no definite morphology was obtained. High resolution transmission electron microscopy (HRTEM) reveals the formation of nanorods oriented along c-axis for those samples prepared with 50% input power. No cavitation at 40% and excessive dissolution at 60% may lead to this type of morphology. Absorption studies showed high absorbance for sulphur doped samples but this was highest for the samples prepared with 60% input power.

  9. Role of size and defects in ultrafast broadband emission dynamics of ZnO nanostructures

    SciTech Connect (OSTI)

    Appavoo, Kannatassen; Liu, Mingzhao; Sfeir, Matthew Y., E-mail: msfeir@bnl.gov [Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973 (United States)

    2014-03-31T23:59:59.000Z

    As wide bandgap materials are nanostructured for optoelectronics and energy technologies, understanding how size and defects modify the carrier dynamics becomes critical. Here, we examine broadband ultraviolet-visible subpicosecond emission dynamics of prototypical ZnO in bulk, nanowire and nanosphere geometries. Using a high-sensitivity transient emission Kerr-based spectrometer, we probe exciton dynamics in the low fluence regime to determine how defects states impact thermalization and recombination rates. In contrast to steady-state measurements, we transiently identify low-energy emission features that originate from localized excitonic states rather than mid-gap states, characterized by distinct recombination kinetics, and correlate to longer thermalization times. These states are critical for understanding the overall excited state lifetime of materials in this size regime, where crystallinity rather than dimensionality plays a primary role in dictating recombination dynamics.

  10. Measurement of the $^{58}$Ni($?$,$?$)$^{62}$Zn reaction and its astrophysical impact

    E-Print Network [OSTI]

    S. J. Quinn; A. Spyrou; E. Bravo; T. Rauscher; A. Simon; A. Battaglia; M. Bowers; B. Bucher; C. Casarella; M. Couder; P. A. DeYoung; A. C. Dombos; J. Grres; A. Kontos; Q. Li; A. Long; M. Moran; N. Paul; J. Pereira; D. Robertson; K. Smith; M. K. Smith; E. Stech; R. Talwar; W. P. Tan; M. Wiescher

    2014-05-23T23:59:59.000Z

    Cross section measurements of the $^{58}$Ni($\\alpha$,$\\gamma$)$^{62}$Zn reaction were performed in the energy range $E_{\\alpha}=5.5-9.5$ MeV at the Nuclear Science Laboratory of the University of Notre Dame, using the NSCL Summing NaI(Tl) detector and the $\\gamma$-summing technique. The measurements are compared to predictions in the statistical Hauser-Feshbach model of nuclear reactions using the SMARAGD code. It is found that the energy dependence of the cross section is reproduced well but the absolute value is overestimated by the prediction. This can be remedied by rescaling the $\\alpha$ width by a factor of 0.45. Stellar reactivities were calculated with the rescaled $\\alpha$ width and their impact on nucleosynthesis in type Ia supernovae has been studied. It is found that the resulting abundances change by up to 5\\% when using the new reactivities.

  11. Crystal structure and magnetic properties and Zn substitution effects on the spin-chain compound Sr{sub 3}Co{sub 2}O{sub 6}

    SciTech Connect (OSTI)

    Wang, Xia [Superconducting Properties Unit, National Institute for Materials Science, 1-1 Namiki, Tsukuba Ibaraki 305-0044 (Japan); Department of Chemistry, Graduate School of Science, Hokkaido University, Sapporo, Hokkaido 060-0810 (Japan); Guo, Yanfeng, E-mail: Yangfeng.Guo@physics.ox.ac.uk [Superconducting Properties Unit, National Institute for Materials Science, 1-1 Namiki, Tsukuba Ibaraki 305-0044 (Japan); Sun, Ying [International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba Ibaraki 305-0044 (Japan); Tsujimoto, Yoshihiro [Materials Processing Unit, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba Ibaraki 305-0047 (Japan); Matsushita, Yoshitaka [Materials Analysis Station, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba Ibaraki 305-0047 (Japan); Yamaura, Kazunari, E-mail: yamaura.kazunari@nims.go.jp [Superconducting Properties Unit, National Institute for Materials Science, 1-1 Namiki, Tsukuba Ibaraki 305-0044 (Japan); Department of Chemistry, Graduate School of Science, Hokkaido University, Sapporo, Hokkaido 060-0810 (Japan)

    2013-08-15T23:59:59.000Z

    The effects of substituting Co on the spin-chain compound Sr{sub 3}Co{sub 2}O{sub 6} with Zn were investigated by synchrotron X-ray diffraction, magnetic susceptibility, isothermal magnetization, and specific heat measurements. To the best of our knowledge, this is the first report to describe the successful substitution of Co in Sr{sub 3}Co{sub 2}O{sub 6} with Zn. The substitution was carried out by a method involving high pressures and temperatures to obtain Sr{sub 3}CoZnO{sub 6}, which crystalized into a K{sub 4}CdCl{sub 6}-derived rhombohedral structure with a space group of R-3c, similar to the host compound. With the Zn substitution, the Ising-type magnetic anisotropy of the host compound remarkably reduced; the newly formed Sr{sub 3}CoZnO{sub 6} became magnetically isotropic with Heisenberg-type characteristics. This could probably be ascribed to the establishment of a different interaction pathway, Co{sup 4+}(S=1/2)OZn{sup 2+}(S=0)OCo{sup 4+}(S=1/2). Details of the magnetic properties of Zn substituted Sr{sub 3}Co{sub 2}O{sub 6} were reported. - Graphical abstract: Crystal structure of the spin-chain compound Sr{sub 3}CoZnO{sub 6} synthesized at 6 GPa. Zn atoms preferably occupy the trigonal prism sites rather than the octahedral sites. As a result, the compound is much magnetically isotropic. Highlights: Effects of substituting Co with Zn on spin-chain magnetism of Sr{sub 3}Co{sub 2}O{sub 6} were studied. High-pressure synthesis resulted in a solid solution of Sr{sub 3}CoZnO{sub 6}. Sr{sub 3}CoZnO{sub 6} showed more isotropic magnetism than the host Sr{sub 3}Co{sub 2}O{sub 6}.

  12. Metalloenzyme chemistry: thermostability study and metal dissociation constant measurement of thermolysin, Co? substituted thermolysin, E. coli Zn?-FDP aldolase, and Co? substituted E. coli FDP aldolase

    E-Print Network [OSTI]

    Chen, Yie Lane

    1989-01-01T23:59:59.000Z

    3on of Native Thr. rmol y'in by 2-r Zn I&7 rr . 2 100 90 00 20 60 f? 60 ? I 2 : ~ t- -i -. Gf ?? 10 -P f- 10 10 6 2. 66610 10 10 01 iC F' igure 2. Activity Restoration of Apothermo]ysin by Co Inn. 2+ 7-4 71 'u Nativ e... to different coordination state preference, Co ion is 2+ ready to form 5 or 6 coordination geometry at the enzyme active site, whereas Zn ion still prefers to form 4 coordination geometry at the enzyme active site. In other words, active site Zn can...

  13. Taheri-Saramad x-ray detector (TSXD): A novel high spatial resolution x-ray imager based on ZnO nano scintillator wires in polycarbonate membrane

    SciTech Connect (OSTI)

    Taheri, A., E-mail: at1361@aut.ac.ir; Saramad, S.; Ghalenoei, S.; Setayeshi, S. [Department of Energy Engineering and Physics, Amirkabir University of Technology, Tehran 15875-4413 (Iran, Islamic Republic of)] [Department of Energy Engineering and Physics, Amirkabir University of Technology, Tehran 15875-4413 (Iran, Islamic Republic of)

    2014-01-15T23:59:59.000Z

    A novel x-ray imager based on ZnO nanowires is designed and fabricated. The proposed architecture is based on scintillation properties of ZnO nanostructures in a polycarbonate track-etched membrane. Because of higher refractive index of ZnO nanowire compared to the membrane, the nanowire acts as an optical fiber that prevents the generated optical photons to spread inside the detector. This effect improves the spatial resolution of the imager. The detection quantum efficiency and spatial resolution of the fabricated imager are 11% and <6.8 ?m, respectively.

  14. Methanol synthesis on ZnO(0001{sup }). IV. Reaction mechanisms and electronic structure

    SciTech Connect (OSTI)

    Frenzel, Johannes, E-mail: johannes.frenzel@theochem.rub.de; Marx, Dominik [Lehrstuhl fr Theoretische Chemie, Ruhr-Universitt Bochum, 44780 Bochum (Germany)

    2014-09-28T23:59:59.000Z

    Methanol synthesis from CO and H{sub 2} over ZnO, which requires high temperatures and high pressures giving rise to a complex interplay of physical and chemical processes over this heterogeneous catalyst surface, is investigated using ab initio simulations. The redox properties of the surrounding gas phase are known to directly impact on the catalyst properties and thus, set the overall catalytic reactivity of this easily reducible oxide material. In Paper III of our series [J. Kiss, J. Frenzel, N. N. Nair, B. Meyer, and D. Marx, J. Chem. Phys. 134, 064710 (2011)] we have qualitatively shown that for the partially hydroxylated and defective ZnO(0001{sup }) surface there exists an intricate network of surface chemical reactions. In the present study, we employ advanced molecular dynamics techniques to resolve in detail this reaction network in terms of elementary steps on the defective surface, which is in stepwise equilibrium with the gas phase. The two individual reduction steps were investigated by ab initio metadynamics sampling of free energy landscapes in three-dimensional reaction subspaces. By also sampling adsorption and desorption processes and thus molecular species that are in the gas phase but close to the surface, our approach successfully generated several alternative pathways of methanol synthesis. The obtained results suggest an Eley-Rideal mechanism for both reduction steps, thus involving near-surface molecules from the gas phase, to give methanol preferentially over a strongly reduced catalyst surface, while important side reactions are of Langmuir-Hinshelwood type. Catalyst re-reduction by H{sub 2} stemming from the gas phase is a crucial process after each reduction step in order to maintain the catalyst's activity toward methanol formation and to close the catalytic cycle in some reaction channels. Furthermore, the role of oxygen vacancies, side reactions, and spectator species is investigated and mechanistic details are discussed based on extensive electronic structure analysis.

  15. Effect of implanted species on thermal evolution of ion-induced defects in ZnO

    SciTech Connect (OSTI)

    Azarov, A. Yu.; Rauwel, P.; Kuznetsov, A. Yu.; Svensson, B. G. [Department of Physics, Centre for Materials Science and Nanotechnology, University of Oslo, PO Box 1048 Blindern, N-0316 Oslo (Norway); Halln, A. [Royal Institute of Technology, KTH-ICT, Electrum 229, SE-164 40, Kista, Stockholm (Sweden); Du, X. L. [Institute of Physics, The Chinese Academy of Sciences, Beijing 100190 (China)

    2014-02-21T23:59:59.000Z

    Implanted atoms can affect the evolution of ion-induced defects in radiation hard materials exhibiting a high dynamic annealing and these processes are poorly understood. Here, we study the thermal evolution of structural defects in wurtzite ZnO samples implanted at room temperature with a wide range of ion species (from {sup 11}B to {sup 209}Bi) to ion doses up to 2??10{sup 16}?cm{sup ?2}. The structural disorder was characterized by a combination of Rutherford backscattering spectrometry, nuclear reaction analysis, and transmission electron microscopy, while secondary ion mass spectrometry was used to monitor the behavior of both the implanted elements and residual impurities, such as Li. The results show that the damage formation and its thermal evolution strongly depend on the ion species. In particular, for F implanted samples, a strong out-diffusion of the implanted ions results in an efficient crystal recovery already at 600?C, while co-implantation with B (via BF{sub 2}) ions suppresses both the F out-diffusion and the lattice recovery at such low temperatures. The damage produced by heavy ions (such as Cd, Au, and Bi) exhibits a two-stage annealing behavior where efficient removal of point defects and small defect clusters occurs at temperatures ?500?C, while the second stage is characterized by a gradual and partial annealing of extended defects. These defects can persist even after treatment at 900?C. In contrast, the defects produced by light and medium mass ions (O, B, and Zn) exhibit a more gradual annealing with increasing temperature without distinct stages. In addition, effects of the implanted species may lead to a nontrivial defect evolution during the annealing, with N, Ag, and Er as prime examples. In general, the obtained results are interpreted in terms of formation of different dopant-defect complexes and their thermal stability.

  16. Polarimetric performance of a Laue lens gamma-ray CdZnTe focal plane prototype

    SciTech Connect (OSTI)

    Curado da Silva, R. M. [Departmento de Fisica, Universidade de Coimbra, P-3000 Coimbra (Portugal); Center for Space Radiations, Univesite Catholique de Louvain (Belgium); Caroli, E.; Stephen, J. B.; Schiavone, F.; Donati, A.; Ventura, G. [Istituto di Astrofisica Spaziale e Fisica Cosmica-Bologna, Via Gobetti 101, I-40129 Bologna (Italy); Pisa, A.; Auricchio, N.; Frontera, F. [Dipartimento di Fisica, Universita di Ferrara, Ferrara (Italy); Del Sordo, S. [Istituto di Astrofisica Spaziale e Fisica Cosmica-Palermo, Via Ugo La Malfa 153, 90146 Palermo (Italy); Honkimaeki, V. [European Synchrotron Radiation Facility, Grenoble (France); Trindade, A. M. F. [Departmento de Fisica, Universidade de Coimbra, P-3000 Coimbra (Portugal)

    2008-10-15T23:59:59.000Z

    A gamma-ray telescope mission concept [gamma ray imager (GRI)] based on Laue focusing techniques has been proposed in reply to the European Space Agency call for mission ideas within the framework of the next decade planning (Cosmic Vision 2015-2025). In order to optimize the design of a focal plane for this satellite mission, a CdZnTe detector prototype has been tested at the European Synchrotron Radiation Facility under an {approx}100% polarized gamma-ray beam. The spectroscopic, imaging, and timing performances were studied and in particular its potential as a polarimeter was evaluated. Polarization has been recognized as being a very important observational parameter in high energy astrophysics (>100 keV) and therefore this capability has been specifically included as part of the GRI mission proposal. The prototype detector tested was a 5 mm thick CdZnTe array with an 11x11 active pixel matrix (pixel area of 2.5x2.5 mm{sup 2}). The detector was irradiated by a monochromatic linearly polarized beam with a spot diameter of about 0.5 mm over the energy range between 150 and 750 keV. Polarimetric Q factors of 0.35 and double event relative detection efficiency of 20% were obtained. Further measurements were performed with a copper Laue monochromator crystal placed between the beam and the detector prototype. In this configuration we have demonstrated that a polarized beam does not change its polarization level and direction after undergoing a small angle (<1 deg.) Laue diffraction inside a crystal.

  17. Optical Properties of Zn(O,S) Thin Films Deposited by RF Sputtering, Atomic Layer Deposition, and Chemical Bath Deposition: Preprint

    SciTech Connect (OSTI)

    Li, J.; Glynn, S.; Christensen, S.; Mann, J.; To, B.; Ramanathan, K.; Noufi, R.; Furtak, T. E.; Levi, D.

    2012-06-01T23:59:59.000Z

    Zn(O,S) thin films 27 - 100 nm thick were deposited on glass or Cu(InxGa1-x)Se2/Molybdenum/glass with RF sputtering, atomic layer deposition, and chemical bath deposition.

  18. Bicolor Mn-doped CuInS{sub 2}/ZnS core/shell nanocrystals for white light-emitting diode with high color rendering index

    SciTech Connect (OSTI)

    Huang, Bo; Dai, Qian; Zhang, Huichao; Liao, Chen; Cui, Yiping; Zhang, Jiayu, E-mail: jyzhang@seu.edu.cn [Advanced Photonic Center, Southeast University, Nanjing 210096 (China); Zhuo, Ningze; Jiang, Qingsong; Shi, Fenghua; Wang, Haibo [Research Institute of Electric Light Source Materials, Nanjing University of Technology, Nanjing 210015 (China)

    2014-09-07T23:59:59.000Z

    We synthesized bicolor Mn-doped CuInS{sub 2} (CIS)/ZnS core/shell nanocrystals (NCs), in which Mn{sup 2+} ions and the CIS core were separated with a ZnS layer, and both Mn{sup 2+} ions and CIS cores could emit simultaneously. Transmission electron microscopy and powder X-ray diffraction measurements indicated the epitaxial growth of ZnS shell on the CuInS{sub 2} core, and electron paramagnetic resonance spectrum indicated that Mn{sup 2+} ions were on the lattice points of ZnS shell. By integrating these bicolor NCs with commercial InGaN-based blue-emitting diodes, tricolor white light-emitting diodes with color rendering index of 83 were obtained.

  19. Influence of Gas Flow Rate for Formation of Aligned Nanorods in ZnO Thin Films for Solar-Driven Hydrogen Production

    SciTech Connect (OSTI)

    Shet, S.; Chen, L.; Tang, H.; Nuggehalli, R.; Wang, H.; Yan, Y.; Turner, J.; Al-Jassim, M.

    2012-04-01T23:59:59.000Z

    ZnO thin films have been deposited in mixed Ar/N{sub 2} gas ambient at substrate temperature of 500 C by radiofrequency sputtering of ZnO targets. We find that an optimum N{sub 2}-to-Ar ratio in the deposition ambient promotes the formation of well-aligned nanorods. ZnO thin films grown in ambient with 25% N{sub 2} gas flow rate promoted nanorods aligned along c-axis and exhibit significantly enhanced photoelectrochemical (PEC) response, compared with ZnO thin films grown in an ambient with different N{sub 2}-to-Ar gas flow ratios. Our results suggest that chamber ambient is critical for the formation of aligned nanostructures, which offer potential advantages for improving the efficiency of PEC water splitting for H{sub 2} production.

  20. Room-temperature photomagnetism in the spinel ferrite (Mn,Zn,Fe)3O4 as seen via soft x-ray magnetic circular dichroism

    E-Print Network [OSTI]

    Bettinger, J.S.

    2010-01-01T23:59:59.000Z

    photomagnetism in the spinel ferrite (Mn,Zn,Fe)3O4 as seendoped garnets 1 , doped spinel ferrites 2 , doped perovskiteIn the doped garnets and ferrites, the microscopic origin of

  1. Final results of an experiment to search for 2beta processes in zinc and tungsten with the help of radiopure ZnWO4 crystal scintillators

    E-Print Network [OSTI]

    P. Belli; R. Bernabei; F. Cappella; R. Cerulli; F. A. Danevich; S. d'Angelo; A. Incicchitti; V. V. Kobychev; D. V. Poda; V. I. Tretyak

    2011-10-18T23:59:59.000Z

    A search for the double beta decay of zinc and tungsten isotopes has been performed with the help of radiopure ZnWO4 crystal scintillators (0.1-0.7 kg) at the Gran Sasso National Laboratories of the INFN. The total exposure of the low background measurements is 0.529 kg yr. New improved half-life limits on the double beta decay modes of 64Zn, 70Zn, 180W, and 186W have been established at the level of 10^{18}-10^{21} yr. In particular, limits on double electron capture and electron capture with positron emission in 64Zn have been set: T_{1/2}(2\

  2. Fabrication of the ZnO thin films using wet-chemical etching processes on application for organic light emitting diode (OLED) devices

    E-Print Network [OSTI]

    Hong, Byungyou

    - sively used in solar cells, touch panels, heat mirrors, organic electro- luminescence devices (OLED- chemical etching behaviors of ZnO films were also investigated using various chemicals. In order

  3. Determination of lateral size distribution of type-II ZnTe/ZnSe stacked submonolayer quantum dots via spectral analysis of optical signature of the Aharanov-Bohm excitons

    SciTech Connect (OSTI)

    Ji, Haojie; Dhomkar, Siddharth; Roy, Bidisha; Kuskovsky, Igor L. [Department of Physics, Queens College of CUNY, Queens, New York 11367 (United States); The Graduate Center of CUNY, New York, New York 10016 (United States); Shuvayev, Vladimir [Department of Physics, Queens College of CUNY, Queens, New York 11367 (United States); Deligiannakis, Vasilios; Tamargo, Maria C. [The Graduate Center of CUNY, New York, New York 10016 (United States); Department of Chemistry, City College of CUNY, New York, New York 10031 (United States); Ludwig, Jonathan [National High Magnetic Field Laboratory, Tallahassee, Florida 32310 (United States); Department of Physics, Florida State University, Tallahassee, Florida 32306 (United States); Smirnov, Dmitry [National High Magnetic Field Laboratory, Tallahassee, Florida 32310 (United States); Wang, Alice [Evans Analytical Group, Sunnyvale, California 94086 (United States)

    2014-10-28T23:59:59.000Z

    For submonolayer quantum dot (QD) based photonic devices, size and density of QDs are critical parameters, the probing of which requires indirect methods. We report the determination of lateral size distribution of type-II ZnTe/ZnSe stacked submonolayer QDs, based on spectral analysis of the optical signature of Aharanov-Bohm (AB) excitons, complemented by photoluminescence studies, secondary-ion mass spectroscopy, and numerical calculations. Numerical calculations are employed to determine the AB transition magnetic field as a function of the type-II QD radius. The study of four samples grown with different tellurium fluxes shows that the lateral size of QDs increases by just 50%, even though tellurium concentration increases 25-fold. Detailed spectral analysis of the emission of the AB exciton shows that the QD radii take on only certain values due to vertical correlation and the stacked nature of the QDs.

  4. Formation and characterization of microstructure of as-cast Mg6Gd4YxZn0.5Zr (x = 0.3, 0.5 and 0.7 wt.%) alloys

    SciTech Connect (OSTI)

    Wu, Y.J. [National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University, Shanghai 200240 (China); State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); Xu, C. [National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University, Shanghai 200240 (China); Zheng, F.Y. [National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University, Shanghai 200240 (China); State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); Peng, L.M., E-mail: plm616@sjtu.edu.cn [National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University, Shanghai 200240 (China); State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); Zhang, Y.; Ding, W.J. [National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University, Shanghai 200240 (China); State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2013-05-15T23:59:59.000Z

    Mg6Gd4YxZn0.5Zr (x = 0.3, 0.5 and 0.7 wt.%) alloys were prepared via conventional ingot metallurgy (I/M) in this study. The as-cast microstructures of these alloys were established by X-ray diffraction (XRD) analyses, optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM) observations. Lamellar stacking order (SF) and 14H-type long period stacking order (LPSO) structure within ?-Mg matrix are formed in the three as-cast alloys. The eutectic secondary phase is (Mg,Zn){sub 24}(Gd,Y){sub 5} for the alloy containing 0.3 wt.% Zn, while, it is (Mg,Zn){sub 3}(Gd,Y) for the alloys containing 0.5 wt.% Zn and 0.7 wt.% Zn. Moreover, X phase-(Mg,Zn){sub 12}(Gd,Y) is formed in the latter two as-cast alloys. - Highlights: LPSO structure has first been found in as-cast Mg6Gd4YxZn0.5Zr. X-phase exists in as-cast Mg6Gd4Y0.3(0.5)Zn0.5Zr. Zn content results in different ?-phase in the studied alloys.

  5. Phonons and electronic states of ZnO, Al2O3 and Ge in the presence of time reversal symmetry

    E-Print Network [OSTI]

    Nabben, Reinhard

    as double valued, these follow from the inclusion of spin, of wurtzite (e.g. ZnO) , trigonal (e.g. Al2O3 to the presence or absence of Time Reversal Symmerty (TRS). We have found a number of phonons in wurtzite Wurtzite (C4 6v-space group) wide band semiconductors: ZnO, GaN, 6H-SiC, etc., have received considerable

  6. 1100/,,1102... twin boundaries in wurtzite ZnO and group-III-nitrides Yanfa Yan and M. M. Al-Jassim

    E-Print Network [OSTI]

    Pennycook, Steve

    1100/,,1102... twin boundaries in wurtzite ZnO and group-III-nitrides Yanfa Yan and M. M. Al that the same twin boundaries in wurtzite group-III-nitrides adopt the same structure, but the twin states in the band gap in either ZnO or the wurtzite group-III-nitrides. DOI: 10.1103/PhysRevB.71

  7. PHYSICAL REVIEW B 83, 125201 (2011) Compositional dependence of structural and electronic properties of Cu2ZnSn(S,Se)4 alloys

    E-Print Network [OSTI]

    Gong, Xingao

    2011-01-01T23:59:59.000Z

    structured Cu2ZnSnS4 (CZTS) is a promising semiconductor for low-cost and sustainable thin-film solar cell properties of Cu2ZnSn(S,Se)4 alloys for thin film solar cells Shiyou Chen,1,2 Aron Walsh,3 Ji-Hui Yang,1 X. G, Colorado 80401, USA (Received 15 December 2010; published 1 March 2011) A thin-film solar cell based on Cu2

  8. Performance and Loss Analyses of High-Efficiency CBD-ZnS/Cu(In1-xGax)Se2 Thin-Film Solar Cells

    E-Print Network [OSTI]

    Sites, James R.

    1 Performance and Loss Analyses of High-Efficiency CBD-ZnS/Cu(In1-xGax)Se2 Thin-Film Solar Cells, Setagaya-ku, Tokyo 157-8572, Japan (Received ) KEYWORDS: ZnS buffer, Cu(In,Ga)Se2, thin-film solar cells alternative to CdS in polycrystalline thin-film Cu(In1-xGax)Se2 (CIGS) solar cells. Cells with efficiency

  9. SPECTROSCOPIC STUDIES OF EXTREMELY METAL-POOR STARS WITH THE SUBARU HIGH DISPERSION SPECTROGRAPH. V. THE Zn-ENHANCED METAL-POOR STAR BS 16920-017

    SciTech Connect (OSTI)

    Honda, Satoshi [Gunma Astronomical Observatory, Takayama-mura, Agatsuma, Gunma 377-0702 (Japan); Aoki, Wako [National Astronomical Observatory, Osawa, Mitaka, Tokyo 181-8588 (Japan); Beers, Timothy C. [Department of Physics and Astronomy and JINA: Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, MI 48824-1116 (United States); Takada-Hidai, Masahide, E-mail: honda@kwasan.kyoto-u.ac.jp, E-mail: aoki.wako@nao.ac.jp, E-mail: beers@pa.msu.edu, E-mail: hidai@apus.rh.u-tokai.ac.jp [Liberal Arts Education Center, Tokai University, Hiratsuka, Kanagawa 259-1292 (Japan)

    2011-04-01T23:59:59.000Z

    We report Zn abundances for 18 very metal-poor stars studied in our previous work, covering the metallicity range -3.2< [Fe/H] <-2.5. The [Zn/Fe] values of most stars show an increasing trend with decreasing [Fe/H] in this metallicity range, confirming the results found by previous studies. However, the extremely metal-poor star BS 16920-017([Fe/H] =-3.2) exhibits a significantly high [Zn/Fe] ratio ([Zn/Fe] = +1.0). Comparison of the chemical abundances of this object with HD 4306, which has similar atmospheric parameters to BS 16920-017, clearly demonstrates a deficiency of {alpha} elements and neutron-capture elements in this star, along with enhancements of Mn and Ni, as well as Zn. The association with a hypernova explosion that has been proposed to explain the high Zn abundance ratios found in extremely metal-poor stars is a possible explanation, although further studies are required to fully interpret the abundance pattern of this object.

  10. Structure and red shift of optical band gap in CdOZnO nanocomposite synthesized by the sol gel method

    SciTech Connect (OSTI)

    Mosquera, Edgar, E-mail: edemova@ing.uchile.cl [Laboratorio de Materiales a Nanoescala, Departamento de Ciencia de los Materiales, Facultad de Ciencias Fsicas y Matemticas, Universidad de Chile, Av. Tupper 2069, Santiago (Chile); Pozo, Ignacio del, E-mail: ignacio.dpf@gmail.com [Facultad de Ciencias Naturales, Matemticas y del Medio Ambiente, Universidad Tecnolgica Metropolitana, Av. Jos Pedro Alessandri 1242, Santiago (Chile); Morel, Mauricio, E-mail: mmorel@ing.uchile.cl [Laboratorio de Materiales a Nanoescala, Departamento de Ciencia de los Materiales, Facultad de Ciencias Fsicas y Matemticas, Universidad de Chile, Av. Tupper 2069, Santiago (Chile)

    2013-10-15T23:59:59.000Z

    The structure and the optical band gap of CdOZnO nanocomposites were studied. Characterization using X-ray diffraction (XRD), transmission electron microscopy (TEM) and diffuse reflectance spectroscopy (DRS) analysis confirms that CdO phase is present in the nanocomposites. TEM analysis confirms the formation of spheroidal nanoparticles and nanorods. The particle size was calculated from DebeySherrer?s formula and corroborated by TEM images. FTIR spectroscopy shows residual organic materials (aromatic/Olefinic carbon) from nanocomposites surface. CdO content was modified in the nanocomposites in function of polyvinylalcohol (PVA) added. The optical band gap is found to be red shift from 3.21 eV to 3.11 eV with the increase of CdO content. Photoluminescence (PL) measurements reveal the existence of defects in the synthesized CdOZnO nanocomposites. - Graphical abstract: Optical properties of ZnO, CdO and ZnO/CdO nanoparticles. Display Omitted - Highlights: TEM analysis confirms the presence of spherical nanoparticles and nanorods. The CdO phase is present in the nanocomposites. The band gap of the CdOZnO nanocomposites is slightly red shift with CdO content. PL emission of CdOZnO nanocomposite are associated to structural defects.

  11. Electrodeposition of hierarchical ZnO/Cu{sub 2}O nanorod films for highly efficient visible-light-driven photocatalytic applications

    SciTech Connect (OSTI)

    Ren, S. T.; Fan, G. H.; Liang, M. L.; Wang, Q. [Department of Optoelectronic Science, Harbin Institute of Technology at Weihai, Weihai 264209 (China); Zhao, G. L., E-mail: zhaoguoliang@hit.edu.cn [School of Materials and Engineering, Harbin Institute of Technology at Weihai, Weihai 264209 (China)

    2014-02-14T23:59:59.000Z

    The development of high-performance visible-light-responsive photocatalytic materials has attracted widespread interest due to their potential applications in the environmental and energy industries. In this work, hierarchical ZnO nanorods films were successfully prepared on the stainless steel mesh substrates via a simple two-step seed-assisted electrodeposition route. Cu{sub 2}O nanoparticles were then electrodeposited on the surface of ZnO nanorods to form the core-shell heterostructure. The synthesized ZnO/Cu{sub 2}O nanocomposites were characterized by X-ray diffraction, field-emission scanning electron microscopy, and UV-visible spectrophotometer. Due to the branched hierarchical morphologies and core-shell structure, ZnO/Cu{sub 2}O nanomaterials show a prominent visible-light-driven photocatalytic performance under the low-intensity light irradiation (40?mW/cm{sup 2}). The influence of some experimental parameters, such as Cu{sub 2}O loading amount, ZnO morphologies, the substrate type, and the PH of the Cu{sub 2}O precursor solution on ZnO/Cu{sub 2}O photocatalytic performance was evaluated.

  12. Indication of Te segregation in laser-irradiated ZnTe observed by in situ coherent-phonon spectroscopy

    SciTech Connect (OSTI)

    Shimada, Toru [Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin (Germany); Hirosaki University, 1 Bunkyo-cho, Hirosaki, Aomori 036-8152 (Japan); Kamaraju, N., E-mail: nkamaraju@lanl.gov [Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin (Germany); Los Alamos National Laboratory, Center for Integrated Nanotechnologies, Los Alamos, New Mexico 87545 (United States); Frischkorn, Christian [Department of Physics, Free University of Berlin, Arnimallee 14, 14195 Berlin (Germany); Wolf, Martin; Kampfrath, Tobias [Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin (Germany)

    2014-09-15T23:59:59.000Z

    We irradiate a ZnTe single crystal with 10-fs laser pulses at a repetition rate of 80?MHz and investigate its resulting gradual modification by means of coherent-phonon spectroscopy. We observe the emergence of a phonon mode at about 3.6?THz whose amplitude and lifetime grow monotonously with irradiation time. The speed of this process depends sensitively on the pump-pulse duration. Our observations strongly indicate that the emerging phonon mode arises from a Te phase induced by multiphoton absorption of incident laser pulses. A potential application of our findings is laser-machining of microstructures in the bulk of a ZnTe crystal, a highly relevant electrooptic material.

  13. Growth optimization and structural analysis for ferromagnetic Mn-doped ZnO layers deposited by radio frequency magnetron sputtering

    SciTech Connect (OSTI)

    Abouzaid, M.; Ruterana, P.; Liu, C.; Morkoc, H. [SIFCOM UMR 6176 CNRS-ENSICAEN, 6 Boulevard du Marechal Juin, 14050 Caen Cedex (France); Department of Electrical Engineering, Virginia Commonwealth University, Richmond Virginia 23284 (United States)

    2006-06-01T23:59:59.000Z

    The effect of the deposition temperature on the crystalline quality of (Zn,Mn)O is investigated in thin films prepared by radio frequency magnetron sputtering on c-plane sapphire and GaN substrates. The layers are made of a 0.5 {mu}m Mn-doped layer towards the surface on top of a 150 nm pure ZnO buffer. Depending on the deposition temperature, the layers can exhibit a columnar structure; the adjacent domains are rotated from one another by 90 deg. , putting [1010] and [1120] directions face to face. At high Mn concentration the columnar structure is blurred by the formation of Mn rich precipitates. Only one variety of domains is observed at an optimal deposition temperature of 500 deg. C: they are slightly rotated around the [0001] axis (mosaic growth) and bounded by threading dislocations.

  14. Fusion Cross Section in the {sup 4,6}He+{sup 64}Zn Collisions Around the Coulomb Barrier

    SciTech Connect (OSTI)

    Fisichella, M. [Dipartimento di Fisica, Universita di Messina, Messina (Italy); INFN-Laboratori Nazionali del Sud and sezione di Catania, Catania (Italy); Di Pietro, A.; Figuera, P.; Marchetta, C. [INFN-Laboratori Nazionali del Sud and sezione di Catania, Catania (Italy); Lattuada, M.; Musumarra, A.; Pellegriti, M. G.; Scuderi, V.; Strano, E.; Torresi, D. [INFN-Laboratori Nazionali del Sud and sezione di Catania, Catania (Italy); Dipartimento di Fisica ed Astronomia, Universita di Catania, Catania (Italy); Milin, M. [Department of Physics Faculty of Science University of Zagreb, Zagreb (Croatia); Skukan, N.; Zadro, M. [Ruder Boskovic Institute, Zagreb (Croatia)

    2011-10-28T23:59:59.000Z

    New fusion data for the {sup 4}He+{sup 64}Zn system at sub-barrier energies are measured to cover the same energy region of previous measurements for {sup 6}He+{sup 64}Zn. Aim of the experiment was to compare the fusion excitation functions for the two system to investigate on the effects of the {sup 6}He neutron-halo structure on the fusion reaction mechanism at energies around the Coulomb barrier. The fusion cross section was measured by using an activation technique. Comparing the two systems, we observe an enhancement of the fusion cross section in the reaction induced by {sup 6}He, at and below the Coulomb barrier.

  15. Methanol Synthesis over Cu/ZnO/Al2O3: The Active Site in Industrial Catalysis

    SciTech Connect (OSTI)

    Behrens, Malte

    2012-03-28T23:59:59.000Z

    Unlike homogeneous catalysts, heterogeneous catalysts that have been optimized through decades are typically so complex and hard to characterize that the nature of the catalytically active site is not known. This is one of the main stumbling blocks in developing rational catalyst design strategies in heterogeneous catalysis. We show here how to identify the crucial atomic structure motif for the industrial Cu/ZnO/Al{sub 2}O{sub 3} methanol synthesis catalyst. Using a combination of experimental evidence from bulk-, surface-sensitive and imaging methods collected on real high-performance catalytic systems in combination with DFT calculations. We show that the active site consists of Cu steps peppered with Zn atoms, all stabilized by a series of well defined bulk defects and surface species that need jointly to be present for the system to work.

  16. Origins of low resistivity and Ge donor level in Ge ion-implanted ZnO bulk single crystals

    SciTech Connect (OSTI)

    Kamioka, K.; Oga, T.; Izawa, Y.; Kuriyama, K. [College of Engineering and Research Center of Ion Beam Technology, Hosei University Koganei, Tokyo 184-8584 (Japan); Kushida, K. [Departments of Arts and Sciences, Osaka Kyoiku University Kashiwara, Osaka 582-8582 (Japan)

    2013-12-04T23:59:59.000Z

    The energy level of Ge in Ge-ion implanted ZnO single crystals is studied by Hall-effect and photoluminescence (PL) methods. The variations in resistivity from ?10{sup 3} ?cm for un-implanted samples to ?10{sup ?2} ?cm for as-implanted ones are observed. The resistivity is further decreased to ?10{sup ?3} ?cm by annealing. The origins of the low resistivity are attributed to both the zinc interstitial (Zn{sub i}) related defects and the electrical activated Ge donor. An activation energy of Ge donors estimated from the temperature dependence of carrier concentration is 102 meV. In PL studies, the new peak at 372 nm (3.33 eV) related to the Ge donor is observed in 1000 C annealed samples.

  17. Large positive magnetoresistance effects in the dilute magnetic semiconductor (Zn,Mn)Se in the regime of electron hopping

    SciTech Connect (OSTI)

    Jansson, F., E-mail: fjansson@abo.fi; Wiemer, M.; Gebhard, F.; Baranovskii, S. D. [Department of Physics and Material Sciences Center, Philipps-University, D-35032 Marburg (Germany); Nenashev, A. V. [Institute of Semiconductor Physics, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, 630090 Novosibirsk (Russian Federation); Petznick, S.; Klar, P. J. [Institute of Experimental Physics I, Justus-Liebig-University Giessen, D-35392 Giessen (Germany); Hetterich, M. [Institut fr Angewandte Physik and Center for Functional Nanostructures (CFN), Universitt Karlsruhe, D-76131 Karlsruhe (Germany)

    2014-08-28T23:59:59.000Z

    Magnetoresistance in dilute magnetic semiconductors is studied in the hopping transport regime. Measurements performed on Cl-doped Zn{sub 1x}Mn{sub x}Se with x?Zn,Mn)Se with donor concentrations below the metalinsulator transition.

  18. Near-resonant second-order nonlinear susceptibility in c-axis oriented ZnO nanorods

    SciTech Connect (OSTI)

    Liu, Weiwei; Wang, Kai; Long, Hua; Wang, Bing, E-mail: wangbing@hust.edu.cn; Lu, Peixiang, E-mail: lupeixiang@hust.edu.cn [Wuhan National Laboratory for Optoelectronics and School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); Chu, Sheng [School of Physics and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China)

    2014-08-18T23:59:59.000Z

    Near-resonant second-harmonic generation (SHG) in c-axis oriented ZnO nanorods is studied under the femtosecond laser with wavelength from 780?nm to 810?nm. A highly efficient SHG is obtained, which is attributed to the d{sub 131} component of the second-order nonlinear susceptibility. The largest d{sub 131} value is estimated to be 10.2?pm/V at the pumping wavelength of 800?nm, which indicates a large SHG response of the c-axis oriented ZnO nanorods in the near-resonant region. Theoretical calculation based on finite-difference time-domain simulation suggests a four-fold local-field enhancement of the SHG.

  19. Tailoring the coercivity in ferromagnetic ZnO thin films by 3d and 4f elements codoping

    SciTech Connect (OSTI)

    Lee, J. J.; Xing, G. Z., E-mail: guozhong.xing@unsw.edu.au; Yi, J. B.; Li, S. [School of Materials Science and Engineering, The University of New South Wales, Sydney, New South Wales 2052 (Australia)] [School of Materials Science and Engineering, The University of New South Wales, Sydney, New South Wales 2052 (Australia); Chen, T. [Department of Physics, The Chinese University of Hong Kong, Shatin (Hong Kong)] [Department of Physics, The Chinese University of Hong Kong, Shatin (Hong Kong); Ionescu, M. [Australian Nuclear Science and Technology Organization, Sydney, New South Wales 2234 (Australia)] [Australian Nuclear Science and Technology Organization, Sydney, New South Wales 2234 (Australia)

    2014-01-06T23:59:59.000Z

    Cluster free, Co (3d) and Eu (4f) doped ZnO thin films were prepared using ion implantation technique accompanied by post annealing treatments. Compared with the mono-doped ZnO thin films, the samples codoped with Co and Eu exhibit a stronger magnetization with a giant coercivity of 1200?Oe at ambient temperature. This was further verified through x-ray magnetic circular dichroism analysis, revealing the exchange interaction between the Co 3d electrons and the localized carriers induced by Eu{sup 3+} ions codoping. The insight gained with modulating coercivity in magnetic oxides opens up an avenue for applications requiring non-volatility in spintronic devices.

  20. Interface structure and anisotropic strain relaxation of nonpolar wurtzite (1120) and (1010) orientations: ZnO epilayers grown on sapphire

    SciTech Connect (OSTI)

    Chauveau, J.-M. [Centre de Recherche sur l'Hetero-Epitaxie et ses Applications, Centre National de la Recherche Scientifique (CRHEA-CNRS), Rue B. Gregory, F-06560 Valbonne Sophia Antipolis (France); Physics Department, University of Nice Sophia Antipolis, Parc Valrose, F-06102 Nice Cedex 2 (France); Vennegues, P.; Lauegt, M.; Deparis, C.; Zuniga-Perez, J.; Morhain, C. [Centre de Recherche sur l'Hetero-Epitaxie et ses Applications, Centre National de la Recherche Scientifique (CRHEA-CNRS), Rue B. Gregory, F-06560 Valbonne Sophia Antipolis (France)

    2008-10-01T23:59:59.000Z

    The interface properties between nonpolar ZnO and sapphire have been studied using high resolution transmission electron microscopy. Two nonpolar orientations are investigated: a- and m-orientations corresponding to [1120] and [1010] crystallographic directions. After the definition of the epitaxial relationships and the resulting initial lattice mismatch, we show that nonpolar ZnO can be grown on sapphire with perfectly flat interfaces. Geometrical misfit dislocations are observed at the interface ZnO/sapphire and their density gives the residual strain in the layer. A strong anisotropy in the strain relaxation is found along the two perpendicular in-plane directions. This anisotropy may be explained in terms of initial anisotropic mismatch yielding different relaxation processes. A domain matching epitaxy is observed in m- and a-oriented layers for mismatches larger than 9% while a lattice matching epitaxy, in which the relaxation is driven by nucleation and glide of dislocations, is observed in a-oriented ZnO along the [0001] in-plane direction. In order to explain the observed relaxation the activated slip systems are calculated for both nonpolar orientations as a function of the in-plane stress due to the anisotropic mismatch. There is a major difference from the polar orientations. Low energy prismatic slip systems can be effective for plastic relaxation in the nonpolar orientations because they are no longer parallel to the growth direction, which is the case of c-oriented layers, nor to the applied stress. Our results can be directly extended to other nonpolar wurtzite structures such as III-nitrides.