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1

OTS NOTE  

Office of Legacy Management (LM)

* pp4 r G- .2- * pp4 r G- .2- OTS NOTE DATE: April 24, 1991 TO: Alexander Williams FROM: Dan Stou tF L SUBJECT: American Potash and Chemical Company Elimination Recommendation The attached memorandum and supporting documents are the basis for our recommendation to eliminate the former American Potash and Chemical Company site from further consideration under FUSRAP. The site is located in West Hanover, Massachusetts. Documents discovered to date indicating use or handling of radioactive material by American Potash consist of a National Lead Company of Ohio (NLO) internal memorandum which discusses tests American Potash performed for Union Carbide Nuclear Corporation (Oak Ridge), an Atomic Energy Commission (AEC) prime contractor. The site predecessor, National Fireworks Ordnance

2

James L. Liveman, Acting AssLBtaOt  

Office of Legacy Management (LM)

1 1 - * -w : L i P / ' 5- . . . c James L. Liveman, Acting AssLBtaOt Secretay for 2nv??Onnur_nt ( IQ UZT'ZXSI~ OF :ZZ&JA On Dctezher 6, 1977, and ridtcr E. smitil, Edward J . Jaacwsky , De?ar+nent of hrgarme SaCanal Laborawry (AS.), _- _. - - -zatzgy (DOE), visited tlhe University of iJeva&, Ekekay ScMal of %iaes. The purpose ___ was to dLscu!38 tke -8: opcraZ4Qns of tbcse fuCti'I?-'n= **-A-- A e fl' the v?L&gl: ~~ BHIC --c-r &atic . - . dtselopxzeat studies on vsrlous tppes of ursrAum orw. -- ,------- Dlscussians uer4 held ~5th Dr. kztkwr Bakr XII, Da, tisd ?Lr. trsly Franh, R&Fatiac Safety Offl~er. . . D*Qcu~siO=: sd:k Dr. Baker establfshad that work witi UZZL&IZI .ore Ls - 0 still b-2 petfazzzd 21 the azws where the PSC wurk was pcrforned.

3

Generic OTS, EPRI Generic Operator Training Simulator, Version 2.0  

Science Conference Proceedings (OSTI)

The EPRI Generic Operator Training Simulator, Generic OTS Version 2.0 is a PC-based training simulator that allows hands-on training for dispatchers, using a generic 29 station model. Simulation-based training has long been recognized as an important component of power system operator training. The Generic OTS, which can be run on multiple platforms, allows for realistic simulations of many power system phenomena. A generic Power and Light model can be employed, or the user has the ability to include the...

2006-12-13T23:59:59.000Z

4

Error Recovery for a Boiler System with OTS PID Controller Tom Anderson, Mei Feng, Steve Riddle, Alexander Romanovsky  

E-Print Network (OSTI)

Error Recovery for a Boiler System with OTS PID Controller Tom Anderson, Mei Feng, Steve Riddle-The-Shelf) item. The case study used a Simulink model of a steam boiler system together with an OTS PID in practice, employing software models of the PID controller and the steam boiler system rather than

Newcastle upon Tyne, University of

5

Error Recovery for a Boiler System with OTS PID Controller Tom Anderson, Mei Feng, Steve Riddle, Alexander Romanovsky  

E-Print Network (OSTI)

1 Error Recovery for a Boiler System with OTS PID Controller Tom Anderson, Mei Feng, Steve Riddle employing an OTS (Off-The-Shelf) item. The case study used a Simulink model of a steam boiler system, employing software models of the PID controller and the steam boiler system rather than conducting

Newcastle upon Tyne, University of

6

Rhombohedrally Distorted ?-Au5-xZn8+y Phases in the Au-Zn System  

SciTech Connect

The region of the Au–Zn phase diagram encompassing ?-brass-type phases has been studied experimentally from 45 to 85 atom % Zn. The ? phases were obtained directly from the pure elements by heating to 680 °C in evacuated silica tubes, followed by annealing at 300 °C. Powder X-ray and single-crystal diffraction studies show that ?-“Au5Zn8” phases adopt a rhombohedrally distorted Cr5Al8 structure type rather than the cubic Cu5Zn8 type. The refined compositions from two single crystals extracted from the Zn- and Au-rich loadings are Au4.27(3)Zn8.26(3)?0.47 (I) and Au4.58(3)Zn8.12(3)?0.3 (II), respectively (? = vacancy). These (I and II) refinements indicated both nonstatistical mixing of Au and Zn atoms as well as partially ordered vacancy distributions. The structures of these ? phases were solved in the acentric space group R3m (No. 160, Z = 6), and the observed lattice parameters from powder patterns were found to be a = 13.1029(6) and 13.1345(8) Å and c = 8.0410(4) and 8.1103(6) Å for crystals I and II, respectively. According to single-crystal refinements, the vacancies were found on the outer tetrahedron (OT) and octahedron (OH) of the 26-atom cluster. Single-crystal structural refinement clearly showed that the vacancy content per unit cell increases with increasing Zn, or valence-electron concentration. Electronic structure calculations, using the tight-binding linear muffin-tin orbital method with the atomic-sphere approximation (TB-LMTO-ASA) method, indicated the presence of a well-pronounced pseudogap at the Fermi level for “Au5Zn8” as the representative composition, an outcome that is consistent with the Hume–Rothery interpretation of ? brass.

Thimmaiah, Srinivasa [Ames Laboratory; Miller, Gordon J. [Ames Laboratory

2013-01-16T23:59:59.000Z

7

O/O'/07D/-I0072J'OtJo?  

Office of Legacy Management (LM)

O/O'/07D/-I0072J'OtJo? O/O'/07D/-I0072J'OtJo? u.s Depai'tntenf,of Energy Ohio Field Office Parcel 6, 7, and 8 A.emedy (Monitored Natura'i Attenuation) Groundwater Monitoring Plan . , CH2MHILL * This page intentionally left blank Parcel 6, 7, a.nd 8 Remedy (Monit'ored Natural Attetluation) Groundwater M.onitoring Plan DQcenibe.r· 200$ F'Ii1ai Prepared for the U.S. Department of Energy Ohio Field Office This page intentionally left blank ABSTRACT Parcels 6, 7, and 8 are three tracts of land that comprise the majority of the remaining Mound Closure Project in ~iamisburg, Ohio. The final remedy for Parcels 6, 7, and 8 combines institutional controls in the form of deed. restrictions on future land and groundwater use and monitored natural attenuation (MNA). MNA is being utilized as a

8

OTS NOTE  

Office of Legacy Management (LM)

@ 'Alexander Williams @ 'Alexander Williams FROM: Ed Mitchellqm SUBJECT: W.R. Grace Elimination Recommendation The purpose of this note is to provide you with certain information regarding the recommendation to eliminate W.R. Grace Company (the former Heavy Minerals Company), Chicago,Illinois, from consideration as a site under FUSRAP. Enclosed is a memo dated July 9, 1990: FUSRAP Considered Site Recommendation, for W.R. Grace Company. It recommends elimination in accordance with FUSRAP protocol. Also enclosed is some typed input material (dated July 9, 1990) about the site that you may want to use in the preparation of your Record of Elimination. If you concur, please provide a Record of Elimination to indicate DOE's decision to eliminate this site. In lieu of a separate memo, you may want

9

OTS NOTE  

Office of Legacy Management (LM)

August 4, 1992 August 4, 1992 TO: Alexander Williams FROM: Ed Mitchell, Steve Fieser ' 565 SUBJECT: Revised Designation Package for Baker Brothers Site We have prepared the Designation Summary you requested for Baker Brothers Site, in Toledo, Ohio. This package supersedes the previous one provided on May 1, 1992, to reflect the documents that have since been finalized. The designationpackage consists of the following: o Designation Summary (8/4/92) o Authority Review (7/16/92) o Radiological Survey (3/92) A copy of each is enclosed. Also enclosed for your consideration is draft correspondence to FSRD, to designate this site for remedial action under FUSRAP. cc: C. Young, w/o enclosure J. Herman, w/o enclosure i DOE disk copy, EM-421 EM-421 Author (A. Williams, 3-8149)

10

OTS NOTE  

Office of Legacy Management (LM)

January 15, 1991 January 15, 1991 TO: Alexander Williams FROM: Dan Stout@ SUBJECT: Gruen Watch Company Consideration Recommendation Attached for your review is a consideration recommendation for the Gruen Watch Co. in Norwood, Ohio. The company was identified by an NLO radiological survey report. Gruen appears to have participated in brief test operations using their 60 ton mechanical press to shave and stamp washers. Small quantities of uranium appear to be involved, and the 1956 radiological surveys do not indicate significant dispersion of uranium during stamping operations. Because of the scarcity of records, limited period of operation for NLO, and absence of evidence of contamination, I recommend the site be eliminated from FUSRAP. Please call me if you have any questions.

11

OTS NOTE  

Office of Legacy Management (LM)

5, 1991 5, 1991 TO: Alexander Williams FROM: .B Dan Stout SUBJECT: Processes Research Elimination Recommendation The attached memorandum and supporting documents are the basis for our recommendation to eliminate the Processes Research, Incorporated site from further consideration under FUSRAP. The site is located in Cincinnati, Ohio. No documents have been discovered to date which specifically indicate use or handling of radioactive material by Processes Research. The principal record discovered is a letter subcontract from National Lead of Ohio (NLO) to Processes Research, dated 10/21/1952, for development of machining methods. A 1953 list of active NLO subcontracts does not list Processes Research. No additional records pertaining to Processes Research have been

12

OTS NOTE  

Office of Legacy Management (LM)

March 22, 1991 March 22, 1991 TO: A. Williams FROM: 0. Sto> Attached is a revised site summary for the Exxon Company in Linden, New Jersey. The summary incorporates new information from a file search and from a conversation with.an NRC inspector. The specific locations of AEC/MED operations have not been identified. .I." -:;1 5':' :?iv,::.;& & had been decontami "ated. The NRC inspector did note that the kC.Mackenzie E. Mitchell C. Young .c. FUSRAP NJ.18 Exxon Research and Engineering Company The Former Standard Oil Development Company Linden, New Jersey Site Function In the spring of 1942, Standard Oil Development Company (SODC) was contracted to be in charge of obtaining materials for work being do the Metallurgical Laboratories and subsequently the MED. SODC play

13

OTS NOTE  

Office of Legacy Management (LM)

Michigan, is the APV Chemical Company. Documents discovered to date indicating use or handling of radioactive material by the Baker-Perkins Company include nine Analytical Data...

14

OTS NOTF  

Office of Legacy Management (LM)

NOTF NOTF DATE: December 18, 1990 TO: Alexander Williams, FROM:~ Dan Stou d- SUBJECT: Additional Considered Sites During historical searches I have identified several potential considered sites. .Two historical documents referencing three sites are attached and highlighted. The first attachment refers ,to'a four pound uranium rod shipped to the Catalytic Company (the Fernald construction contractor). It also notes that 100 pounds of uranium oxide was shipped to the,Milwaukee airport for Fred Stroke (an AEC/Argonne employee). I recommend these two sites be added to the eliminated database, as no additional information is available. The second attachment refers to potential thread rolling of 1500 Savannah River plant slugs at the Reed Rolled Thread and Die Co. in Worcester, MA.

15

Treated Effluent Disposal Facility (TEDF) Operator Training Station (OTS) System Configuration Management Plan  

Science Conference Proceedings (OSTI)

The Treated Effluent Disposal Facility Operator Training Station (TEDF 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). It consists of PC compatible computers and a Programmable Logic Controller (PLC) designed to emulate the responses of various plant components connected to or under the control of the CCS. The system trains operators by simulating the normal operation but also has the ability to force failures of different equipment allowing the operator to react and observe the events. The paper describes organization, responsibilities, system configuration management activities, software, and action plans for fully utilizing the simulation program.

Carter, R.L. Jr.

1994-06-01T23:59:59.000Z

16

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

NLE Websites -- All DOE Office Websites (Extended Search)

OT SPECIFIED I OT SPECIFIED I OTHER AMENDMENT OF SOLICITATI ON/MODIFICATION OF CONTRACT 2 AM EN DMENT/MODIFIC ATION NO 1 B 6 ISSUED BY CODE Oak UrJge u . s . De arcment of Energ y P . O. Box 2001 Oak Ridge TN 37831 3 EFFccnv E DA E Sep Bl c..c.k _6C 00518 8 NAME AND ADDRESS OF CONTRACTOR INo ~/e.' CO Ull/y. Sial. and ZIP Cod.) OAK RIDGE A SOCIATED Ul IVERSITIES , P . O. BOX 117 OAK R-DGE Ttl 37830-6218 N . CODE 0411522 24 FAC ILITY CODE 1 CONTRACT 10 CODE 4 R OUISITIONIPU RCHASr. REO NO IuS lL 7 ADMIN ISTER ED BY rlf QlherlhBn lIem B) Oak Ridge o . s . Dep rtment of Energ y P . O. Box 2001 Oak Ridge TN 37831 (xl 9A AMENDMENT OF SOlICrTATlON NO. 98 DA TEO I SEE ITEM 11) .. 10A MODIFIC ATION OF CO NTRACTIORD ER NO A DE-AC05 - 060R 23 100 l OB DATED (SEE ITEM 13) 12/ 21/ 2005 11 . THIS ITEM ONLY APPLIES TO AMENDMENTS OF SOLICITA

17

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

DOE Green Energy (OSTI)

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).

Mathur, A K

1983-09-01T23:59:59.000Z

18

GAUAGHER AND GALLAGHER ATTORmYS AT LAW, P.C. Ot4ECONWRJTIONPUtA  

Office of Legacy Management (LM)

j ; ij 7 iir I,::? ir s1: 141 TL-2 j ; ij 7 iir I,::? ir s1: 141 TL-2 tj .> Ii el)sTorl GAUAGHER AND GALLAGHER ATTORmYS AT LAW, P.C. Ot4ECONWRJTIONPUtA BOSTON. MASS. 02129 March 7, 1990 (617) 241.8aoo ?AX. (617) 141*?6W VIA TELEFAX Park Owen USDOE: Nuclear Facility De commissioning and site Remedial hotion oak Ridge National Laboratory P. 0. Box 2008 Building 2001-6050 Oak Ridge, TN 37831-6050 Re: Wesaahouse, Bloomfield, NJ Our File No.: 15094 (09) near M r. Owen: Pursuant to our telephone conversation of March 7, 1990, P1ca.w fincl the following documents enclo6e.A fnr yot~r perusfil: 1. Report on Radiological Status Building 7 Westinghouse Electric Corp. (Source NJDEP-DHWM-ECRA); 2. Cover Letter and Attachment (NRC to Westinghouse): Report on Radiological status on Westinghouse Building

19

BASIN BLAN CO BLAN CO S OT ERO IGNAC IO-BLANCO AZ TEC BALLAR  

U.S. Energy Information Administration (EIA) Indexed Site

BOE Reserve Class BOE Reserve Class No 2001 reserves 0.1 - 10 MBOE 10.1 - 100 MBOE 100.1 - 1,000 MBOE 1,000.1- 10,000 MBOE 10,000.1 - 100,000 MBOE > 100,000 MBOE Basin Outline AZ UT NM CO 1 2 Index Map for 2 Paradox-San Juan Panels 2001 Reserve Summary for All Paradox-San Juan Basin Fields Total Total Total Number Liquid Gas BOE of Reserves Reserves Reserves Fields (Mbbl) (MMcf) (Mbbl) Paradox-San Juan 250 174,193 20,653,622 3,616,464 Basin CO NM IGNAC IO-BLANCO IGNAC IO-BLANCO IGNAC IO-BLANCO IGNAC IO-BLANCO IGNAC IO-BLANCO BASIN BASIN BLAN CO BLAN CO BASIN BASIN BASIN BASIN BASIN BASIN BISTI BAL LAR D BASIN BISTI BLA NCO S OT ERO BAL LAR D LIND RITH W BASIN BLA NCO BLA NCO S BLA NCO S TAPAC ITO GAVIL AN BASIN BLA NCO The mapped oil and gas field boundary outlines were created by the Reserves and Production Division, Office of Oil and Gas, Energy Information Administration pursuant to studies required by

20

?ot8rh QI ahnloal Corporation In Hart IUnover, Ma86rohusett8,  

Office of Legacy Management (LM)

GE 1 GE 1 ;" qr)-1 s?llq ' p raspy.. c" ifa K. mris I talked with Hr. Wllllm cIF(Iy, Metrllurgist, Wnlon CarbId@ Nuclear cOrp8ny, 08k B&t&$@, Tenne66ee, on April 26, 1961. He informed me th&t the #rtioMl Northern birislon, Ame~ic6.n ?ot8rh QI ahnloal Corporation In Hart IUnover, Ma86rohusett8, la pePfopn1~ lo8lve forming studier for the. ilnion olo)w Wuolem Conpmy "p l7?JHa). The work at National Northern l#rirc.- alon ir under the 6upenl6lon of Ehsll Phillpohuc4~, v of Spealrl Prcbduots. The @ox& to data ha8 been pwfonwd wlth 430 strlnle66 rteel and urma%um metal - both hot snb 0018 wor4c have been performed at pr688u~r fmm 100,000 to 900,000 prl. The shape of the pleu88 na not dlrolored. In 6<lon work ha6 been done with

Note: This page contains sample records for the topic "zn zurn ot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

BASIN BLAN CO BLAN CO S OT ERO IGNAC IO-BLANCO AZ TEC BALLAR  

U.S. Energy Information Administration (EIA) Indexed Site

Liquids Reserve Class Liquids Reserve Class No 2001 liquids reserves 0.1 - 10 Mbbl 10.1 - 100 Mbbl 100.1 - 1,000 Mbbl 1,000.1- 10,000 Mbbl 10,000.1 - 100,000 Mbbl Basin Outline AZ UT NM CO 1 2 Index Map for 2 Paradox-San Juan Panels 2001 Reserve Summary for All Paradox-San Juan Basin Fields Total Total Total Number Liquid Gas BOE of Reserves Reserves Reserves Fields (Mbbl) (MMcf) (Mbbl) Paradox-San Juan 250 174,193 20,653,622 3,616,464 Basin CO NM IGNAC IO-BLANCO IGNAC IO-BLANCO IGNAC IO-BLANCO IGNAC IO-BLANCO IGNAC IO-BLANCO BASIN BASIN BLAN CO BLAN CO BASIN BASIN BASIN BASIN BASIN BASIN BISTI BAL LAR D BASIN BISTI BLA NCO S OT ERO BAL LAR D LIND RITH W BASIN BLA NCO BLA NCO S BLA NCO S TAPAC ITO GAVIL AN BASIN BLA NCO The mapped oil and gas field boundary outlines were created by the Reserves and Production Division, Office of Oil and Gas, Energy Information Administration pursuant to studies required by

22

BASIN BLAN CO BLAN CO S OT ERO IGNAC IO-BLANCO AZ TEC BALLAR  

U.S. Energy Information Administration (EIA) Indexed Site

Gas Reserve Class Gas Reserve Class No 2001 gas reserves 0.1 - 10 MMCF 10.1 - 100 MMCF 100.1 - 1,000 MMCF 1,000.1- 10,000 MMCF 10,000.1 - 100,000 MMCF > 100,000 MMCF Basin Outline AZ UT NM CO 1 2 Index Map for 2 Paradox-San Juan Panels 2001 Reserve Summary for All Paradox-San Juan Basin Fields Total Total Total Number Liquid Gas BOE of Reserves Reserves Reserves Fields (Mbbl) (MMcf) (Mbbl) Paradox-San Juan 250 174,193 20,653,622 3,616,464 Basin CO NM IGNAC IO-BLANCO IGNAC IO-BLANCO IGNAC IO-BLANCO IGNAC IO-BLANCO IGNAC IO-BLANCO BASIN BASIN BLAN CO BLAN CO BASIN BASIN BASIN BASIN BASIN BASIN BISTI BAL LAR D BASIN BISTI BLA NCO S OT ERO BAL LAR D LIND RITH W BASIN BLA NCO BLA NCO S BLA NCO S TAPAC ITO GAVIL AN BASIN BLA NCO The mapped oil and gas field boundary outlines were created by the Reserves and Production Division, Office of Oil and Gas, Energy Information Administration pursuant to studies required by

23

ZnO-ZnTe Nanocone Heterojunctions  

Science Conference Proceedings (OSTI)

Semiconductor nanostructure heterojunctions are expected to be efficient structures for next-generation photovoltaic solar cells, radiation detectors, and light-emitting diodes. In this letter we report heterojunctions made of vertically aligned ZnO/ZnTe nanocones synthesized using a combination of thermal vapor deposition and pulsed-laser deposition (PLD). The ZnO nanocones and nanorods were synthesized as cores by utilizing the growth rate difference between central and boundary sites of precursor domains during thermal vapor deposition. The p-n heterojunctions were subsequently formed by growing ZnTe as shells on the nanocone surface using PLD. The ZnTe shells were polycrystalline structures, while ZnO cores were wurzite structures. The p-n junction of the nanocone core-shell structure exhibited I-V characteristics consistent with a p-n diode, but the nanorod junction did not. These structural and electric characteristics indicate that the ZnO nanocones are more feasible than ZnO nanorods as heterojunctions because the sloping facets of the nanocones facilitate deposition of ZnTe by PLD without the deleterious effects of shadowing. Furthermore, based on theoretical modeling of nanostructure heterojunctions, the nanocone-based junction exhibits an electrostatic potential profile that is much more effective for carrier transport than the electrostatic potential for the nanorod-based junction.

Lee, Sang Hyun [ORNL; Smith, Barton [ORNL; Zhang, Xiaoguang [ORNL; Seo, Sung Seok A [ORNL; Bell, Zane W [ORNL; Xu, Jun [ORNL

2010-01-01T23:59:59.000Z

24

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

SciTech Connect

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.

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

25

In-Zn (Indium - Zinc)  

Science Conference Proceedings (OSTI)

In-Zn crystallographic data...In-Zn crystallographic data Phase Composition, wt% Zn Pearson symbol Space group (In) 0 to 1 tI 2 I 4/ mmm (Zn) 99.8 to 100 hP 2 P 6 3 / mmc...

26

On arithmetic partitions of Zn  

Science Conference Proceedings (OSTI)

Generalizing a classical problem in enumerative combinatorics, Mansour and Sun counted the number of subsets of Z"n without certain separations. Chen, Wang, and Zhang then studied the problem of partitioning Z"n into arithmetical progressions of a given ...

Victor J. W. Guo; Jiang Zeng

2009-07-01T23:59:59.000Z

27

Doped colloidal ZnO nanocrystals  

Science Conference Proceedings (OSTI)

Colloidal ZnO nanocrystals are promising for a wide range of applications due to the combination of unique multifunctional nature and remarkable solution processability. Doping is an effective approach of enhancing the properties of colloidal ZnO nanocrystals ...

Yizheng Jin; Yuping Ren; MoTao Cao; Zhizhen Ye

2012-01-01T23:59:59.000Z

28

OTS NOTE DATE: TO: FROM:  

Office of Legacy Management (LM)

TO: FROM: March 25, 1991 A. Williams D. stout P SUBJECT: Elimination Recommendation for the Star Cutter Corporation The .attached memorandum and supporting documents are the basis for our recommendation to eliminate the former Star Cutter Corporation site from further consideration under FUSRAP. The site is located in Farmington Hills, Michigan. Documents discovered to date which indicate use or handling of radioactive material by Star Cutter consist of two Analytical Data Sheets, dated June 29, 1956, prepared by the National Lead Company of Ohio (NLO), an Atomic Energy Commission (AEC) prime contractor. The data sheets report the results of radiological monitoring conducted during operation of an oil- cooled drilling/hollowing machine. The sheets record measurements during

29

_u J, ot the mountain~  

E-Print Network (OSTI)

& Beverly Gerding Karen & Thomas Jeppson + Cris Kodiak Mary & William Kuhn Michael & Cheryl McMains Paula

O'Laughlin, Jay

30

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

DOE Patents (OSTI)

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.

Bhattacharya, Raghu N. (Littleton, CO)

2009-11-03T23:59:59.000Z

31

P2.19 MOCVD Growth of ZnO/ZnS Core-Shell Nanowires Arrays for ...  

Science Conference Proceedings (OSTI)

Dye sensitized solar cells have also been demonstrated using ZnO nanotips grown ... Their application in photovoltaic devices of the type GZO/ZnO-ZnS/Ag and ...

32

Application of ZnO Nanowires for Energy Harvesting Technology  

Science Conference Proceedings (OSTI)

The electric energy from ZnO nanowire can also be stored to power light emitting diode. This nanotechnology demonstrated with ZnO nanowires implies feasible ...

33

Transparent p-ZnO by oxidation of Zn-based compounds  

SciTech Connect

We report on the fabrication of ZnO:N by thermal oxidation of Zn-based compounds. In particular, we achieved p-type conductivity with carrier concentration in mid 1017 cm-3 range and mobility of {approx}10 cm2/Vs using sputter-deposited zinc nitride as starting material. The transmittance of p-ZnO:N in the whole visible spectrum is 70-80% making it very interesting for transparent electronics.

Kaminska, E.; Piotrowska, A.; Kowalczyk, E. [Institute of Electron Technology, Warsaw (Poland); Kossut, J. [Institute of Physics, Polish Academy of Sciences, Warsaw (Poland); ERATO Semiconductor Spintronics (Poland); Przezdziecka, E.; Dobrowolski, W.; Dynowska, E.; Butkute, R.; Jakiela, R.; Aleszkiewicz, M.; Janik, E. [Institute of Physics, Polish Academy of Sciences, Warsaw (Poland); Barcz, A. [Institute of Electron Technology, Warsaw, (Poland); Institute of Physics, Polish Academy of Sciences, Warsaw (Poland)

2005-06-30T23:59:59.000Z

34

Preparation and Electrical Property of Co-Zn Oxides and Ni-Zn ...  

Science Conference Proceedings (OSTI)

Digital multimeter was used to measure the electrical resistivity of the samples. The lowest electrical resistivity is Co : Zn = 2 : 1 as the anode material of cathodic  ...

35

Surface morphologies of homoepitaxial ZnO on Zn- and O-polar substrates by plasma assisted molecular beam epitaxy  

SciTech Connect

Homoepitaxial ZnO layers are grown on Zn-polar (0001) and O-polar (0001) surfaces of single crystal ZnO substrates by plasma assisted molecular beam epitaxy. It is found that the growth conditions to obtain smooth surfaces are significantly different for the two surface polarities. For growth on Zn-polar surface, moderate temperature (650 deg. C) and highly O-rich condition (low Zn/O{sub 2}) are required, while high temperature (1000-1050 deg. C) and Zn-rich condition (high Zn/O{sub 2} ratio) are essential for growth on O-polar surfaces.

Xu Huaizhe; Ohtani, K.; Yamao, M.; Ohno, H. [Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)

2006-08-14T23:59:59.000Z

36

Corrosion analysis of Zn –Sn alloys  

Science Conference Proceedings (OSTI)

The EIS spectrums were adjusted according two equivalent circuit models, R(RQ) ... by Combining Thermoelectric Materials and Dye-Sensitized Solar Cell in Series ... Investigation on the activation energy of ZnO Thin-Film Transistors with Hf ...

37

ZnSe light?emitting diodes  

Science Conference Proceedings (OSTI)

We report the successful fabrication of ZnSe p?n junction light?emitting diodes in which Li and Cl are used as p?type and n?type dopants

J. Ren; K. A. Bowers; B. Sneed; D. L. Dreifus; J. W. Cook Jr.; J. F. Schetzina; R. M. Kolbas

1990-01-01T23:59:59.000Z

38

Synthesis, characterization, and applications of ZnO nanowires  

Science Conference Proceedings (OSTI)

ZnO nanowires (or nanorods) have been widely studied due to their unique material properties and remarkable performance in electronics, optics, and photonics. Recently, photocatalytic applications of ZnO nanowires are of increased interest in environmental ...

Yangyang Zhang; Manoj K. Ram; Elias K. Stefanakos; D. Yogi Goswami

2012-01-01T23:59:59.000Z

39

The Characterization of Various ZnO Nanostructures Using Field ...  

Science Conference Proceedings (OSTI)

Various morphologies and sizes of ZnO materials have led to a wide range of promising applications. Although research related to the applications of ZnO is ...

40

Optical properties of ZnO-alloyed nanocrystalline films  

Science Conference Proceedings (OSTI)

ZnO is emerging as one of the materials of choice for UV applications. It has a deep excitonic energy level and a direct bandgap of ?3.4 eV. Alloying ZnO with certain atomic constituents adds new optical and electronic functionalities to ZnO. This ...

Hui Che; Jesse Huso; John L. Morrison; Dinesh Thapa; Michelle Huso; Wei Jiang Yeh; M. C. Tarun; M. D. McCluskey; Leah Bergman

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "zn zurn ot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Electroluminescence of ZnO-based semiconductor heterostructures  

SciTech Connect

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)

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

42

PU/ZnO composites for biomedical applications; Compósitos PU/ZnO para aplicações biomédicas.  

E-Print Network (OSTI)

??The present work is focused on the preparation and characterization of biomedical devices able to elicit different biological responses. Polyurethane/zinc oxide composites (PU/ZnO) appear as… (more)

Luís, Jorge Louro

2011-01-01T23:59:59.000Z

43

Structural properties of Zn-ZnO core-shell microspheres grown by hot-filament CVD technique  

Science Conference Proceedings (OSTI)

We report the hot-filament chemical vapor deposition (HFCVD) growth of Zn-ZnO core-shell microspheres in the temperature range of 350-650°C only using ZnO pellets as raw material. The samples were characterized by scanning electron microscope (SEM), ...

R. López; T. Díaz; G. García; R. Galeazzi; E. Rosendo; A. Coyopol; M. Pacio; H. Juárez; A. I. Oliva

2012-01-01T23:59:59.000Z

44

Interaction of CO with Surface PdZn Alloys  

SciTech Connect

The adsorption and bonding configuration of CO on clean and Zn-covered Pd(111) surfaces was studied using Low Energy Electron Diffraction (LEED), Temperature Programmed Desorption (TPD) and High Resolution Electron Energy Loss Spectroscopy (HREELS). LEED and TPD results indicate that annealing at 520 K is sufficient to induce reaction between adsorbed Zn atoms and the Pd(111) surface resulting in the formation of an ordered surface PdZn alloy. Carbon monoxide was found to bond more weakly to the Zn/Pd(111) alloy surfaces compared to clean Pd(111). Zn addition was also found to alter the preferred adsorption sites for CO from threefold hollow to atop sites. Similar behavior was observed for supported Pd-Zn/Al2O3 catalysts. The results of this study show that both ensemble and electronic effects play a role in how Zn alters the interactions of CO with the surface.

Jeroro, E.; Lebarbier, Vanessa MC; Datye, Abhaya; Wang, Yong; Vohs, John M.

2007-12-01T23:59:59.000Z

45

Impact of air-exposure on the chemical and electronic structure ofZnO:Zn3N2 thin films  

SciTech Connect

The chemical and electronic surface structure of ZnO:Zn3N2 ("ZnO:N") thin films with different N contents was investigated by soft x-ray emission spectroscopy. Upon exposure to ambient air (in contrast to storage in vacuum), the chemical and electronic surface structure of the ZnO:N films changes substantially. In particular, we find that the Zn3N2/(Zn3N2+ZnO) ratio decreases with exposure time and that this change depends on the initial N content. We suggest a degradation mechanism based on the reaction of the Zn3N2 content with atmospheric humidity.

Bar, M.; Ahn, K.-S.; Shet, S.; Yan, Y.; Weinhardt, L.; Fuchs, O.; Blum, M.; Pookpanratana, S.; George, K.; Yang, W.; Denlinger, J.D.; Al-Jassim, M.; Heske, C.

2008-09-08T23:59:59.000Z

46

CdZnTe technology for gamma ray detectors  

Science Conference Proceedings (OSTI)

CdZnTe detector technology has been developed at NASA Goddard for imaging and spectroscopy applications in hard x-ray and gamma ray astronomy. A CdZnTe strip detector array with capabilities for arc second imaging and spectroscopy has been built as a prototype for a space flight gamma ray burst instrument. CdZnTe detectors also have applications for medical imaging

Carl Stahle; Jack Shi; Peter Shu; Scott Barthelmy; Ann Parsons; Steve Snodgrass

1998-01-01T23:59:59.000Z

47

AMORPHOUS THIN FILMS CONSISTING OF TERNARY MgZnCa ...  

Science Conference Proceedings (OSTI)

Jul 20, 2012 ... AMORPHOUS THIN FILMS CONSISTING OF TERNARY MgZnCa-ALLOYS by K. Schlüter, C. Zamponi, U. Schürmann, N. Hort, L. Kienle, K.U. ...

48

ZnO and MgZnO nanocrystalline flexible films: optical and material properties  

Science Conference Proceedings (OSTI)

An emerging material for flexible UV applications is MgxZn1-xO which is capable of tunable bandgap and luminescence in the UV range of ?3.4 eV-7.4 eV depending on the composition x. Studies on the optical ...

Jesse Huso; John L. Morrison; Hui Che; Jency P. Sundararajan; Wei Jiang Yeh; David McIlroy; Thomas J. Williams; Leah Bergman

2011-01-01T23:59:59.000Z

49

Magnetic resonance studies on ZnO nanocrystals  

Science Conference Proceedings (OSTI)

ZnO nanocrystals with diameters ranging from 4 to 50 nm were prepared via a wet chemical method and post-growth annealing treatments. The electron paramagnetic resonance (EPR) spectra of the nanocrystals show the resonance of electron centers with g-value ... Keywords: K ? P theory, ZnO nanocrystal, electronic paramagnetic resonance (EPR), magnetic resonance

H. Zhou; A. Hofstaetter; D. M. Hofmann; B. K. Meyer

2003-05-01T23:59:59.000Z

50

ZnS-Graphene nanocomposite: Synthesis, characterization and optical properties  

Science Conference Proceedings (OSTI)

A ZnS-Graphene nanocomposite was prepared by a facile one-step hydrothermal method using zinc nitrate hexahydrate, ethylenediamine and carbon disulfide as precursors, graphene oxide as a template. The composite was characterized by X-ray power diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, Fourier transform infrared, Raman spectra and fluorescence spectroscopy. The results show that graphene oxide was reduced to graphene in the hydrothermal reaction process. Simultaneously, the graphene sheets in the composite are exfoliated and decorated with ZnS nanoparticles. Furthermore, Raman and fluorescence properties of the composite were observed. ZnS-Graphene nanocomposite displays surface-enhanced Raman scattering activity for graphene oxide, and fluorescence enhancement property compared with pure ZnS sample. - Graphical abstract: Approach of reaction makes the reduction of grapheme oxide and the deposition of Zns on the grapheme sheets occur simultaneously and overcomes the aggregation of the grapheme sheets and Zns. Highlights: Black-Right-Pointing-Pointer Graphene oxide is reduced to graphene in the hydrothermal reaction process. Black-Right-Pointing-Pointer ZnS nanoparticles are attached onto the almost transparent graphene sheets. Black-Right-Pointing-Pointer ZnS-Graphene system shows surface-enhanced Raman scattering (SERS) activity. Black-Right-Pointing-Pointer ZnS-Graphene system displays relatively better fluorescence property than pure ZnS.

Pan Shugang [Key Laboratory for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Ministry of Education, Nanjing 210094 (China); Liu Xiaoheng, E-mail: xhliu@mail.njust.edu.cn [Key Laboratory for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Ministry of Education, Nanjing 210094 (China)

2012-07-15T23:59:59.000Z

51

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)  

Science Conference Proceedings (OSTI)

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.

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

52

Excitonic spectrum of the ZnO/ZnMgO quantum wells  

Science Conference Proceedings (OSTI)

Excitonic spectrum of the wurtzite ZnO/Zn{sub 1-x}Mg{sub x}O quantum wells with a width on the order of or larger than the Bohr radius of the exciton has been studied; the quantum wells have been grown by the method of molecular beam epitaxy (with plasma-assisted activation of oxygen) on substrates of sapphire (0001). Low-temperature (25 K) spectra of photoluminescence excitation (PLE) have been experimentally measured, making it possible to resolve the peaks of exciton absorption in the quantum well. The spectrum of excitons in the quantum well is theoretically determined as a result of numerical solution of the Schroedinger equation by the variational method. The value of elastic stresses in the structure (used in calculations) has been determined from theoretical simulation of measured spectra of optical reflection. A comparison of experimental data with the results of calculations makes it possible to relate the observed features in the PLE spectra to excitons, including the lower level of dimensional quantization for electrons and two first levels of holes for the A and B valence bands of the wurtzite crystal. The values of the electron and hole masses in ZnO are refined, and the value of the built-in electric field introduced by spontaneous and piezoelectric polarizations is estimated.

Bobrov, M. A., E-mail: largaseal@gmail.com; Toropov, A. A.; Ivanov, S. V. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); El-Shaer, A.; Bakin, A.; Waag, A. [TU Braunschweig, Institute of Semiconductor Technology (Germany)

2011-06-15T23:59:59.000Z

53

Effect of ultraviolet irradiation on luminescence properties of undoped ZnS and ZnS:Ag nanoparticles  

SciTech Connect

Undoped ZnS and ZnS:Ag nanoparticles have been prepared through hydrothemal synthesis. The changes of luminescence properties induced by ultraviolet irradiation have been investigated. For both samples, the initial slight increase in luminescence is ascribed to the fast electron filling, while the succedent decrease is supposed to be caused by nonradiative pathways originating from some unknown photochemical products. The more remarkable decrease in ZnS:Ag is put down to the segregation of Ag on the surfaces of ZnS:Ag nanoparticles. Multipeaks Gaussian fitting is applied to the emission spectra. The fitting peaks around 490 nm in both samples are related with the surface states emission and the fitting peaks around 456 nm in ZnS nanoparticles and 443 nm in ZnS:Ag nanoparticles are attributed to the type of donor-acceptor pair luminescence, which corresponds to the transition between different donor levels and acceptor levels in different samples. A model of stretched exponential function is used to fit the fluorescence decay spectra. Result shows that the introduction of Ag{sup +} ions causes a spectacular lifetime shortening of ZnS. Experiment result also verifies the model as that the lifetimes of both samples are notably shortened after irradiation for 2 h.

Qu Hua; Cao Lixin; Su Ge; Liu Wei; Sun Yuanguang; Dong Bohua [Institute of Material Science and Engineering, Ocean University of China, Qingdao 266100 (China)

2009-11-01T23:59:59.000Z

54

ZnO-graphene Hybrid Quantum Dots Light Emitting Diode  

Science Conference Proceedings (OSTI)

Presentation Title, ZnO-graphene Hybrid Quantum Dots Light Emitting Diode. Author(s), Won Kook Choi, Dong-Ick Son, Soon-Nam Kwon. On-Site Speaker ...

55

Synthesis and characterization of ZnTe hierarchical nanostructures  

Science Conference Proceedings (OSTI)

Single-crystalline ZnTe hierarchical nanostructures have been successfully synthesized by a simple thermal evaporation technology. The as-prepared products were characterized with X-ray diffraction (XRD), scanning electron microcopy (SEM), transmission ...

Baohua Zhang; Fuqiang Guo; Wei Wang

2012-01-01T23:59:59.000Z

56

Pressure Dependence of Creep in Zn and Cd  

Science Conference Proceedings (OSTI)

Bending creep in Zn is reported as a function of hydrostatic confining pressureP up to 8 kbars. The ratio of activation volume for creep to atomic volume

K. L. DeVries; P. Gibbs

1963-01-01T23:59:59.000Z

57

Nanostructured ZnO arrays with self-ZnO layer created using simple electrostatic layer-by-layer assembly  

Science Conference Proceedings (OSTI)

Formation of unique ZnO nanoarrays utilizing photodynamic polymer, surface-relief grating structures, and unique electrostatic layer-by-layer assembly as a simple and economical methodology was demonstrated. Atomic force microscope (AFM), scanning electron ...

PilHo Huh; Seong-Cheol Kim

2012-01-01T23:59:59.000Z

58

Properties of ZnO/Cu/ZnO multilayer films deposited by simultaneous RF and DC magnetron sputtering at different substrate temperatures  

Science Conference Proceedings (OSTI)

ZnO/Cu/ZnO transparent conductive multilayer films are prepared by simultaneous RF sputtering of ZnO and DC sputtering of Cu. The properties of the multilayer films are studied at different substrate temperatures. Sheet resistance of the multilayer film ... Keywords: Electrical and optical properties, Multilayer, Sputtering, TCO

D. R. Sahu; Jow-Lay Huang

2007-03-01T23:59:59.000Z

59

Fluorescent CdSe/ZnS nanocrystal-peptide conjugates for long-term, nontoxic imaging and  

E-Print Network (OSTI)

Fluorescent CdSe/ZnS Nanocrystal-Peptide Conjugates forfluorescent labels, silanized CdSe/ZnS nanocrystal-peptidenuclei of living cells. CdSe/ZnS nanocrystals, or so called

Chen, Fanqing; Gerion, Daniele

2005-01-01T23:59:59.000Z

60

Plasma properties of RF magnetron sputtering system using Zn target  

Science Conference Proceedings (OSTI)

In the present work, we investigate the fundamental properties of magnetron sputtering plasma using Zn target and its deposited Zn thin film. The magnetron sputtering plasma was produced using radio frequency (RF) power supply and Argon (Ar) as ambient gas. A Langmuir probe was used to collect the current from the plasma and from the current intensity, we calculate the electron density and electron temperature. The properties of Zn sputtering plasma at various discharge conditions were studied. At the RF power ranging from 20 to 100 W and gas pressure 5 mTorr, we found that the electron temperature was almost unchanged between 2-2.5 eV. On the other hand, the electron temperature increased drastically from 6 Multiplication-Sign 10{sup 9} to 1 Multiplication-Sign 10{sup 10}cm{sup -3} when the discharge gas pressure increased from 5 to 10 mTorr. The electron microscope images show that the grain size of Zn thin film increase when the discharge power is increased. This may be due to the enhancement of plasma density and sputtered Zn density.

Nafarizal, N.; Andreas Albert, A. R.; Sharifah Amirah, A. S.; Salwa, O.; Riyaz Ahmad, M. A. [Microelectronic and Nanotechnology - Shamsuddin Research Centre (MiNT-SRC), Faculty of Electrical and Electronic Engineering, Universiti Tun Hussein Onn Malaysia 86400 Parit Raja, Batu Pahat, Johor (Malaysia)

2012-06-29T23:59:59.000Z

Note: This page contains sample records for the topic "zn zurn ot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Donor behavior of Sb in ZnO  

Science Conference Proceedings (OSTI)

Electrical behavior of Sb in ZnO:Sb layers doped in a wide concentration range was studied using temperature dependent Hall effect measurements. The layers were grown by plasma-enhanced molecular beam epitaxy, and the Sb concentration was changed by varying the Sb flux, resulting in electron concentrations in the range of 10{sup 16} to nearly 10{sup 20} cm{sup -3}. Upon annealing, the electron concentration increased slightly and more notable was that the electron mobility significantly improved, reaching a room-temperature value of 110 cm{sup 2}/V s and a low-temperature value of 145 cm{sup 2}/V s, close to the maximum of {approx}155 cm{sup 2}/V s set by ionized impurity scattering. Hall data and structural data suggest that Sb predominantly occupies Zn sublattice positions and acts as a shallow donor in the whole concentration range studied. In the layers with high Sb content ({approx}1 at. %), acceptor-type compensating defects (possibly Sb on oxygen sites and/or point-defect complexes involving Sb{sub O}) are formed. The increase of electron concentration with increasing oxygen pressure and the increase in ZnO:Sb lattice parameter at high Sb concentrations suggest that acceptors involving Sb{sub O} rather than Sb{sub Zn}-2V{sub Zn} complexes are responsible for the compensation of the donors.

Liu, H. Y.; Izyumskaya, N.; Avrutin, V.; Oezguer, Ue.; Morkoc, H. [Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, Virginia 23284 (United States); Yankovich, A. B.; Kvit, A. V.; Voyles, P. M. [Department of Materials Science and Engineering, University Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

2012-08-01T23:59:59.000Z

62

Microsoft Word - Zn-DTPA Insert_2 Pages.doc  

NLE Websites -- All DOE Office Websites (Extended Search)

zinc trisodium injection contains the sodium salt of zinc diethylenetriaminepentaacetate. Pentetate zinc zinc trisodium injection contains the sodium salt of zinc diethylenetriaminepentaacetate. Pentetate zinc trisodium is also known as trisodium zinc diethylenetriaminepentaacetate and is commonly referred to as Zn- DTPA. It has a molecular formula of Na3ZnC14H18N3O10 and a molecular weight of 522.7 Daltons. It is represented by the following structural formula: Zn-DTPA is supplied as a clear, colorless, hyperosmolar (1260 mOsmol/kg) solution in a colorless ampoule containing 5 mL. The ampoule contents are sterile, non-pyrogenic and suitable for intravenous administration. Each mL of solution contains the equivalent of 200 mg pentetate zinc trisodium (obtained from 150.51 mg pentetic acid, 31.14 mg zinc oxide and NaOH) and water for injection, USP. The pH of the solution is adjusted

63

Process for fabricating ZnO-based varistors  

DOE Patents (OSTI)

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.

Lauf, Robert J. (Oak Ridge, TN)

1985-01-01T23:59:59.000Z

64

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

NLE Websites -- All DOE Office Websites (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...

65

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

E-Print Network (OSTI)

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 ...

Wong, Brian Alexander

2009-01-01T23:59:59.000Z

66

Excitons in single and double GaAs/AlGaAs/ZnSe/Zn(Cd)MnSe heterovalent quantum wells  

Science Conference Proceedings (OSTI)

Exciton photoluminescence spectra, photoluminescence excitation spectra, and magnetophotoluminescence spectra of single (GaAs/AlGaAs/ZnMnSe) and double (GaAs/AlGaAs/ZnSe/ZnCdMnSe) heterovalent quantum wells formed by molecular beam epitaxy are studied. It is shown that the exciton absorption spectrum of such quantum wells mainly reproduces the resonant exciton spectrum expected for usual quantum wells with similar parameters, while the radiative exciton recombination have substantial distinctions, in particular the additional localization mechanism determined by defects generated by heterovalent interface exists. The nature of these localization centers is not currently clarified; their presence leads to broadening of photoluminescence lines and to an increase in the Stokes shift between the peaks of luminescence and absorption, as well as determining the variation in the magnetic g factor of bound exciton complexes.

Toropov, A. A., E-mail: toropov@beam.ioffe.ru; Kaibyshev, V. Kh.; Terent'ev, Ya. V.; Ivanov, S. V.; Kop'ev, P. S. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation)

2011-02-15T23:59:59.000Z

67

Studies on the properties of sputter-deposited Ag-doped ZnO films  

Science Conference Proceedings (OSTI)

Ag-doped ZnO films were prepared by simultaneous rf magnetron sputtering of ZnO and dc magnetron sputtering of Ag on glass substrate. The influences of dopant content and substrate temperature on the properties of the as-grown films were investigated. ... Keywords: Ag, Electrical and optical properties, Thin films, ZnO

D. R. Sahu

2007-12-01T23:59:59.000Z

68

Enhancement of photoluminescence lifetime of ZnO nanorods making use of thiourea  

Science Conference Proceedings (OSTI)

We have investigated correlation of photoluminescence lifetime between zinc oxide (ZnO) nanorods and thiourea-doped ZnO nanorods (tu: CH4N2S). Aqueous solutions of ZnO nanorods were deposited on glass substrate by using pneumatic ...

Erdal Sönmez; Kadem Meral

2012-01-01T23:59:59.000Z

69

Synthesis and characterization of blue emitting ZnSe quantum dots  

Science Conference Proceedings (OSTI)

In this work we show a new experimental methodology to obtain ZnSe nanocrystals in aqueous solution aiming their application as biophotonic probes. The nanocrystals were obtained using a simple procedure based on the arrested precipitation of ZnSe in ... Keywords: Blue emission, Colloidal synthesis, Water soluble quantum dots, ZnSe

J. J. Andrade; A. G. Brasil, Jr.; P. M. A. Farias; A. Fontes; B. S. Santos

2009-03-01T23:59:59.000Z

70

G1, Temperature Dependent Measurements of ZnO TFTs  

Science Conference Proceedings (OSTI)

Conference Tools for 2010 Electronic Materials Conference ... Propose A Proceedings ... TFTs demonstrate that PEALD ZnO does not contain a large concentration of deep ... [2] T. Tiedje, et. al., Physical Review Letters, 46, 1425, 1981. ..... N5, Breakdown Statistics and Nanowire Device Integration of Self-

71

Design of Shallow p-type Dopants in ZnO (Presentation)  

DOE Green Energy (OSTI)

ZnO is a promising material for short wave-length opto-electronic devices such as UV lasers and LEDs due to its large exciton binding energy and low material cost. ZnO can be doped easily n-type, but the realization of stable p-type ZnO is rather difficult. Using first-principles band structure methods the authors address what causes the p-type doping difficulty in ZnO and how to overcome the p-type doping difficulty in ZnO.

Wei, S.H.; Li, J.; Yan. Y.

2008-05-01T23:59:59.000Z

72

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

NLE Websites -- All DOE Office Websites (Extended Search)

Structural Studies of Al:ZnO Powders and Thin Films Structural Studies of Al:ZnO Powders and Thin Films Monday, June 18, 2012 - 2:00pm SSRL Main Conference Room 137-322 Dr. Bridget Ingham, Associate Investigator, MacDiarmid Institute for Advanced Materials & Nanotechnology Al-doped ZnO (Al:ZnO) is a promising transparent conducting oxide. We have used complementary synchrotron and laboratory techniques to study the incorporation of Al within the ZnO lattice, and measure its effect on the crystallinity of thin films prepared by sol-gel techniques, with an aim to understand how these properties affect the film conductivity. I will present recent results from Al:ZnO powders and thin films, prepared with varying Al concentrations and calcination temperatures. Solid state 27Al NMR and ex situ X-ray diffraction (XRD) were performed on Al:ZnO

73

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

Science Conference Proceedings (OSTI)

Methanol synthesis from syngas (CO/CO2/H2) hydrogenation on the perfect Zn–terminated 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 O–terminated 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 Energy’s 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.

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

2012-08-02T23:59:59.000Z

74

Local structures of polar wurtzites Zn1-xMgxO studied by raman and 67Zn/25Mg NMR spectroscopies and by total neutron scattering  

SciTech Connect

Research in the area of polar semiconductor heterostructures has been growing rapidly, driven in large part by interest in two-dimensional electron gas (2DEG) systems. 2DEGs are known to form at heterojunction interfaces that bear polarization gradients. They can display extremely high electron mobilities, especially at low temperatures, owing to spatial confinement of carrier motions. Recent reports of 2DEG behaviors in Ga{sub 1-x}Al{sub x}N/GaN and Zn{sub 1-x}Mg{sub x}O/ZnO heterostructures have great significance for the development of quantum Hall devices and novel high-electron-mobility transistors (HEMTs). 2DEG structures are usually designed by interfacing a polar semiconductor with its less or more polar alloys in an epitaxial manner. Since the quality of the 2DEG depends critically on interface perfection, as well as the polarization gradient at the heterojunction, understanding compositional and structural details of the parent and alloy semiconductors is an important component in 2DEG design and fabrication. Zn{sub 1-x}Mg{sub x}O/ZnO is one of the most promising heterostructure types for studies of 2DEGs, due to the large polarization of ZnO, the relatively small lattice mismatch, and the large conduction band offsets in the Zn{sub 1-x}Mg{sub x}O/ZnO heterointerface. Although 2DEG formation in Zn{sub 1-x}Mg{sub x}O/ZnO heterostructures have been researched for some time, a clear understanding of the alloy structure of Zn{sub 1-x}Mg{sub x}O is currently lacking. Here, we conduct a detailed and more precise study of the local structure of Zn{sub 1-x}Mg{sub x}O alloys using Raman and solid-state nuclear magnetic resonance (NMR), in conjunction with neutron diffraction techniques.

Proffen, Thomas E [Los Alamos National Laboratory; Kim, Yiung- Il [UCSB; Cadars, Sylvian [UCSB; Shayib, Ramzy [UCSB; Feigerle, Charles S [UNIV OF TENNESSEE; Chmelka, Bradley F [UCSB; Seshadri, Ram [UCSB

2008-01-01T23:59:59.000Z

75

Luminescent and structural properties of ZnO-Ag films  

Science Conference Proceedings (OSTI)

ZnO-Ag thin films were prepared by a two-stage method on glass and sapphire substrates. Ag doping was carried out by a method of close space sublimation at atmospheric pressure. The film thickness is varied from 0.6 to 7 {mu}m. The structural and radiative properties were explored by X-ray diffraction technique, atomic force microscopy, photoluminescence and cathodoluminescence spectroscopy. The influence of the fabricating conditions on the properties of ZnO-Ag films is studied. It is found that the Ag doping modifies the crystalline structure of the films and promotes the oriented growth of monocrystalline blocks with the size of 500-2000 nm in the [0002] direction. Improvement of the crystalline quality correlates with the change of the radiative characteristics of the films. The origin of emission centers is discussed.

Khomchenko, V. S., E-mail: vsk@isp.kiev.ua; Kushnirenko, V. I., E-mail: vl_kush@ukr.net; Papusha, V. P.; Savin, A. K.; Lytvyn, O. S. [National Academy of Sciences of Ukraine, V.E. Lashkaryov Institute of Semiconductor Physics (Ukraine)

2010-05-15T23:59:59.000Z

76

Stability of atoms in the anionic domain (Z)  

E-Print Network (OSTI)

We study the stability and universal behaviour of the ionization energy of N-electron atoms with nuclear charge Z in the anionic domain (Z), considering the nuclear charge Z as an arbitrary (non-integral) parameter. HF and CISD ground state energy calculations were performed for systems with N and N-1 electrons to compute the ionization energies for nuclear charges ranging from the neutral atom region to the anionic instability threshold. As testing systems we choose inert gases (He-like, Ne-like and Ar-like isoelectronic sequences) and alkali metals (Li-like, Na-like, K-like sequences). From the results, it is apparent that, for inert gases case, the stability relation with N is completely inverted in the singly-charged anion region (Z=N-1) with respect to the neutral atom region (Z=N), i.e. larger systems are more stable than the smaller ones. We devised a semi-analytical model (inspired by the zero-range forces theory) which lead us to establish the ionization energy dependence on the nuclear charge n...

Gil, G

2013-01-01T23:59:59.000Z

77

Catalyst free growth of ZnO nanorods by thermal evaporation method  

SciTech Connect

In this work, we report catalyst free growth of ZnO nanorods on n-Si substrate by a low cost thermal evaporation method. The surface morphology, chemical composition and crystalline structure of ZnO nanorods have been determined by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) spectroscopy respectively. It is found that, the as -deposited ZnO seed layer reduces lattice mismatching between ZnO and Si from 40.3 to 0.28%, therefore enhances the subsequent growth and crystalline quality of ZnO nanorods on Si substrate. The present methodology is simple, cost effective and highly applicable for synthesis of ZnO nanorods for optoelectronics applications.

Somvanshi, Divya; Jit, S. [Centre for Research in Microelectronics (CRME), Department of Electronics Engineering Indian Institute of Technology (Banaras Hindu University), Varanasi Uttar Pradesh-221005 (India)

2013-06-03T23:59:59.000Z

78

Effect of near atmospheric pressure nitrogen plasma treatment on Pt/ZnO interface  

SciTech Connect

The effect of near atmospheric pressure nitrogen plasma (NAP) treatment of platinum (Pt)/zinc oxide (ZnO) interface was investigated. NAP can nitride the ZnO surface at even room temperature. Hard x-ray photoelectron spectroscopy revealed that NAP treatment reduced the surface electron accumulation at the ZnO surface and inhibited the Zn diffusion into the Pt electrode, which are critical issues affecting the Schottky barrier height and the ideality factor of the Pt/ZnO structure. After NAP treatment, the Pt Schottky contact indicated an improvement of electrical properties. NAP treatment is effective for the surface passivation and the Schottky contact formation of ZnO.

Nagata, Takahiro; Haemori, Masamitsu; Chikyow, Toyohiro [International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Yamashita, Yoshiyuki [International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Synchrotron X-ray Station at SPring-8, National Institute for Materials Science, 1-1-1 Koto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Yoshikawa, Hideki; Kobayashi, Keisuke [Synchrotron X-ray Station at SPring-8, National Institute for Materials Science, 1-1-1 Koto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Uehara, Tsuyoshi [Sekisui Chemical Co., Ltd., Wadai, Tsukuba, Ibaraki 300-4292 (Japan)

2012-12-01T23:59:59.000Z

79

Etching characteristics of ZnO thin films in chlorine-containing inductively coupled plasmas  

Science Conference Proceedings (OSTI)

This study examined the plasma etching characteristics of ZnO thin films etched in BCl"3/Ar, BCl"3/Cl"2/Ar and Cl"2/Ar plasmas with a positive photoresist mask. The ZnO etch rates were increased in a limited way by increasing the gas flow ratio of the ... Keywords: BCl3, Chlorine, Inductively coupled plasma, Plasma etching, Zinc oxychloride, ZnO

S. W. Na; M. H. Shin; Y. M. Chung; J. G. Han; S. H. Jeung; J. H. Boo; N. -E. Lee

2006-02-01T23:59:59.000Z

80

The Effect of Zn-Rich Coatings on the Environmentally Assisted ...  

Science Conference Proceedings (OSTI)

... that offered by conventional coatings employed in armored vehicles. Improved corrosion protection via Zn-rich primers has been shown to improve the general ...

Note: This page contains sample records for the topic "zn zurn ot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Ternary Phase Diagram of the Zn-Sn-P System for Fabrication of ...  

Science Conference Proceedings (OSTI)

First, we establish the phase diagram by equilibrium experiments using zinc, tin and their phosphides. At 700 ºC, ZnSnP2 is almost stoichiometry, ...

82

Synthesis of ordered large-scale ZnO nanopore arrays  

SciTech Connect

An effective approach is demonstrated for growing ordered large-scale ZnO nanopore arrays through radio-frequency magnetron sputtering deposition on porous alumina membranes (PAMs). The realization of highly ordered hexagonal ZnO nanopore arrays benefits from the unique properties of ZnO (hexagonal structure, polar surfaces, and preferable growth directions) and PAMs (controllable hexagonal nanopores and localized negative charges). Further evidence has been shown through the effects of nanorod size and thermal treatment of PAMs on the yielded morphology of ZnO nanopore arrays. This approach opens the possibility of creating regular semiconducting nanopore arrays for the application of filters, sensors, and templates.

Ding, G.Q.; Shen, W.Z.; Zheng, M.J.; Fan, D.H. [Laboratory of Condensed Matter Spectroscopy and Opto-Electronic Physics, Department of Physics, Shanghai Jiao Tong University, 1954 Hua Shan Road, Shanghai 200030 (China)

2006-03-06T23:59:59.000Z

83

Plasma/Laser Assisted Template Free Synthesis of ZnO Pillars  

Science Conference Proceedings (OSTI)

The pillar morphology is achieved via pulsed lasing of plasma synthesized ZnO ... decreasing transmittance with increasing the energy of photon radiation.

84

Microscopic Study on the Interface Reaction between Ti and Al-Zn ...  

Science Conference Proceedings (OSTI)

Presentation Title, Microscopic Study on the Interface Reaction between Ti and Al -Zn Alloy during Ultra-Fast Heat Treatment. Author(s), Yue Zhao, David Nolan, ...

85

Green synthesis of graphene nanosheets/ZnO composites and electrochemical properties  

Science Conference Proceedings (OSTI)

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.

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

86

Simulated Performance of the GammaTracker CdZnTe Handheld ...  

Simulated Performance of the GammaTracker CdZnTe Handheld Radioisotope Identifier Carolyn E. Seifert, Member, IEEE, Mitchell J. Myjak, Member, IEEE, ...

87

Ultrasound Atomizer-Microwave Heating Joint Synthesis of ZnO ...  

Science Conference Proceedings (OSTI)

Formation mechanism of shell ZnO nanostructures has been studied due to the ... Effect of Alloying Elements and Pulsed Electric Current Sintering Parameters ...

88

CdSe/ZnS Nanoparticle Composites with Amine-Functionalized Polyfluoren...  

NLE Websites -- All DOE Office Websites (Extended Search)

CdSeZnS Nanoparticle Composites with Amine-Functionalized Polyfluorene Derivatives for Polymeric Light-Emitting Diodes: Synthesis, Photophysical Properties, and the...

89

Highly Transparent and Conducting ALD of Doped ZnO Thin Films ...  

Science Conference Proceedings (OSTI)

... and Conducting ALD of Doped ZnO Thin Films for TCO Applications · Hybrid Aerogel/Nanorod Functional Materials for Energy and Sensing Applications.

90

Microstructural Design of Piezoelectric ZnO Thin Films as High ...  

Science Conference Proceedings (OSTI)

Abstract Scope, For most piezoelectric (PE) applications, ZnO films having ... Energy Landscape in Frustrated Systems: Cation Hopping and Relaxation in ...

91

Homobuffer thickness effect on the background electron carrier concentration of epitaxial ZnO thin films  

Science Conference Proceedings (OSTI)

Epitaxial ZnO thin films were grown on r-plane sapphire substrates using plasma-assisted molecular-beam epitaxy. ZnO homobuffer layers grown at a lower temperature were introduced to improve the crystallinity of the top ZnO thin films. Thicker homobuffer layers lead to better crystallinity of the subsequent epitaxial ZnO thin films due to the strain relaxation effect. Residual background electron carrier concentration in these undoped ZnO thin films first decreases, then increases as the buffer layer thickness increases from {approx}1 to 30 nm, with a minimum electron concentration of {approx}1x10{sup 17} cm{sup -3} occurring in ZnO homobuffer of {approx}5 nm. These results demonstrate that the optimized ZnO homobuffer thickness to achieve both good ZnO crystallinity and low residual electron concentration is determined by the relative electron carrier concentration ratios and mobility ratios between the buffer and epi-ZnO layers.

Yang, Z.; Zhou, H. M.; Li, L.; Zhao, J. Z.; Liu, J. L. [Department of Electrical Engineering, Quantum Structures Laboratory, University of California, Riverside, California 92521 (United States); Chen, W. V.; Yu, P. K. L. [Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093 (United States)

2010-09-15T23:59:59.000Z

92

Infrared Radiation Properties of CuO-ZnO-Based Sintered Material ...  

Science Conference Proceedings (OSTI)

Presentation Title, Infrared Radiation Properties of CuO-ZnO-Based Sintered Material Prepared for Energy-Saving Coating. Author(s), Chao Lian, Wei Wei, Hao ...

93

Synthesis and characterization of ZnO and Ni doped ZnO nanorods by thermal decomposition method for spintronics application  

SciTech Connect

Zinc oxide nanorods and diluted magnetic semiconducting Ni doped ZnO nanorods were prepared by thermal decomposition method. This method is simple and cost effective. The decomposition temperature of acetate and formation of oxide were determined by TGA before the actual synthesis process. The X-ray diffraction result indicates the single phase hexagonal structure of zinc oxide. The transmission electron microscopy and scanning electron microscopy images show rod like structure of ZnO and Ni doped ZnO samples with the diameter {approx} 35 nm and the length in few micrometers. The surface analysis was performed using X-ray photoelectron spectroscopic studies. The Ni doped ZnO exhibits room temperature ferromagnetism. This diluted magnetic semiconducting Ni doped ZnO nanorods finds its application in spintronics. - Highlights: Black-Right-Pointing-Pointer The method used is very simple and cost effective compared to all other methods for the preparation DMS materials. Black-Right-Pointing-Pointer ZnO and Ni doped ZnO nanorods Black-Right-Pointing-Pointer Ferromagnetism at room temperature.

Saravanan, R.; Santhi, Kalavathy [Materials Science Centre, Department of Nuclear Physics, University of Madras, Guindy Campus, Chennai-600 025 (India); Sivakumar, N. [Amrita Center for Nanosciences, Amrita Research Institute, Kochi-682 041 (India); Narayanan, V. [Department of Inorganic Chemistry, University of Madras, Guindy Campus, Chennai-600 025 (India); Stephen, A., E-mail: stephen_arum@hotmail.com [Materials Science Centre, Department of Nuclear Physics, University of Madras, Guindy Campus, Chennai-600 025 (India)

2012-05-15T23:59:59.000Z

94

Incorporation of Cu Acceptors in ZnO Nanocrystals  

Science Conference Proceedings (OSTI)

Doping of semiconductor nanocrystals is an important problem in nanomaterials research. Using infrared (IR) and x-ray photoelectron spectroscopy (XPS), we have observed Cu acceptor dopants that were intentionally introduced into ZnO nanocrystals. The incorporation of Cu2+ dopants increased as the diameter of the nanocrystals was increased from ~3 to 5 nm. Etching the nanocrystals with acetic acid revealed a core-shell structure, where a 2-nm lightly doped core is surrounded by a heavily doped shell. These observations are consistent with the trapped dopant model, in which dopant atoms stick to the surface of the core and are overgrown by the nanocrystal material.

Oo, W.M.H.; Mccluskey, Matthew D.; Huso, Jesse; Morrison, J.; Bergman, Leah; Engelhard, Mark H.; Saraf, Laxmikant V.

2010-09-16T23:59:59.000Z

95

Neutron-to-proton ratios of quasiprojectile and midrapidity emission in the {sup 64}Zn + {sup 64}Zn reaction at 45 MeV/nucleon  

Science Conference Proceedings (OSTI)

Simultaneous measurement of both neutrons and charged particles emitted in the reaction {sup 64}Zn + {sup 64}Zn at 45 MeV/nucleon allows comparison of the neutron to proton ratio at midrapidity with that at projectile rapidity. The evolution of N/Z in both rapidity regimes with increasing centrality is examined. For the completely reconstructed midrapidity material one finds that the neutron to proton ratio is above that of the overall {sup 64}Zn + {sup 64}Zn system. In contrast, the reconstructed ratio for the quasiprojectile is below that of the overall system. This difference provides the most complete evidence to date of neutron enrichment of midrapidity nuclear matter at the expense of the quasiprojectile.

Theriault, D.; Gauthier, J.; Grenier, F.; Moisan, F.; St-Pierre, C.; Roy, R. [Laboratoire de Physique Nucleaire, Departement de Physique, Universite Laval, Quebec, Quebec G1K 7P4 (Canada); Davin, B.; Hudan, S.; Paduszynski, T.; Souza, R. T. de [Department of Chemistry and Indiana University Cyclotron Facility, Indiana University, Bloomington, Indiana 47405 (United States); Bell, E.; Garey, J.; Iglio, J.; Keksis, A. L.; Parketon, S.; Richers, C.; Shetty, D. V.; Soisson, S. N.; Souliotis, G. A.; Stein, B. C. [Cyclotron Institute, Texas A and M University, College Station, Texas 77843 (United States)] (and others)

2006-11-15T23:59:59.000Z

96

Fabrication and characterization of ZnO nanowire arrays with an investigation into electrochemical sensing capabilities  

Science Conference Proceedings (OSTI)

ZnO nanowire arrays were grown on a Si (100) substrate using the vapor-liquid-solid (VLS) method. ZnO nanowires were characterized by XRD, SEM, bright field TEM, and EDS. They were found to have a preferential orientation along the c-axis. The ...

Jessica Weber; Sathyaharish Jeedigunta; Ashok Kumar

2008-01-01T23:59:59.000Z

97

Magnetic characterizations of sol-gel-produced mn-doped ZnO  

Science Conference Proceedings (OSTI)

Nanoparticles of ZnO doped with 6 at.% Mn were produced by a sol-gel method. X-ray diffraction confirms the hexagonal structure as that of the parent compound ZnO, and high-resolution electron transmission microscopy reveals a single-crystallite lattice. ...

R. Asmatulu; H. Haynes; M. Shinde; Y. H. Lin; Y. Y. Chen; J. C. Ho

2010-01-01T23:59:59.000Z

98

Nitrogen-Doped ZnO Nanowire Arrays for Photoelectrochemical Water Splitting  

E-Print Network (OSTI)

. First, we grow ZnO nanowires on a ZnO nanoparticle seeded indium-tin oxide (ITO) substrate using to the success of hydrogen technology is the efficient generation of hydrogen from a renewable energy source, most of the metal oxides have large bandgap energies, leading to limited light absorption

Li, Yat

99

Degradation of ZnO Window Layer for CIGS by Damp-Heat Exposure: Preprint  

Science Conference Proceedings (OSTI)

This paper summarizes our work with more details and an emphasis on the DH-induced degradation of Al-doped ZnO and Zn1-xMgxO alloys. The other two TCOs, ITO and F:SnO2, are not included here.

Pern, F.J.; To, B.; DeHart, C.; Li, X.; Glick, S. H.; Noufi, R.

2008-08-01T23:59:59.000Z

100

Photoluminescence Characterization of ZnO Thin Films Grown by RF- Sputtering  

Science Conference Proceedings (OSTI)

This article presents photoluminescence (PL) characterization of ZnO thin films deposited by radio-frequency magnetron sputtering method on sapphire and n-type Si (100) substrates. PL measurements were carried out at room temperature to investigate the energy band gaps and optical quality of the ZnO thin films. In order to draw a specific picture of surface morphology of ZnO thin films, atomic force microscope images were taken. All the results were compared to the results obtained from the bulk ZnO sample. The results revealed that the energy band gap of ZnO thin films grown on n-type Si (100) is higher than ZnO on sapphire. However, energy band gap of bulk ZnO is higher compared to both ZnO on n-type Si (100) and sapphire (Al{sub 2}O{sub 3}). This is probably due to the crystalline quality because good crystallinity increases the radiation recombination and hence increase the intensity of the NBE emission.

Bakhori, S. K. Mohd; Ng, S. S.; Ahmad, M. A.; Ahmad, H.; Hassan, Z.; Hassan, H. Abu; Abdullah, M. J. [Nano-optoelectronics Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, 11800, USM, Penang (Malaysia)

2011-03-30T23:59:59.000Z

Note: This page contains sample records for the topic "zn zurn ot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Microstructure and Mechanical Property of Cu-40%Zn-0.5%Cr Alloy ...  

Science Conference Proceedings (OSTI)

Yield stress of extruded P/M Cu-40Zn-0.5Cr brass alloy at 773 K was 514.6 MPa, high value of 54.7% of the conventional P/M Cu60-Zn40 brass alloy at same ...

102

Tailoring Selectivity for Electrocatalytic Oxygen Evolution on Ruthenium Oxides by Zn Substitution  

SciTech Connect

Controlling gas emissions: Versatile control of the selectivity of an oxide electrocatalyst in the oxygen- and chlorine-evolution reactions was demonstrated by Zn substitution in RuO{sub 2}. The incorporation of Zn into the rutile structure alters the cation sequence along the [001] direction and modifies the structure of the active sites for both gas-evolution processes.

Petrykin, V.; Macounova, K; Shlyakhtin, O; Krtil, P

2010-01-01T23:59:59.000Z

103

Nanoimprinted photonic crystals for the modification of the (CdSe)ZnS nanocrystals light emission  

Science Conference Proceedings (OSTI)

We report experimental results of photoluminescence (PL) enhancement in 2D photonic crystals nanoimprinted in functionalized poly-methyl methacrylate (PMMA) based polymer in which (CdSe)ZnS core-shell luminescent nanocrystals (NCs) have been incorporated. ... Keywords: (CdSe)ZnS nanocrystals, Light extraction, Nanoimprint lithography, Photoluminescence, Photonic crystal

V. Reboud; N. Kehagias; M. Zelsmann; M. Striccoli; M. Tamborra; M. L. Curri; A. Agostiano; D. Mecerreyes; J. A. Alduncín; C. M. Sotomayor Torres

2007-05-01T23:59:59.000Z

104

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

E-Print Network (OSTI)

DOI: 10.1002/adma.200702781 Aerogel Templated ZnO Dye-Sensitized Solar Cells** By Thomas W. Hamann silica aerogel films, featuring a large range of controllable thickness and porosity, are prepared as substructure templates. The aerogel templates are coated with ZnO via atomic layer deposition (ALD) to yield

105

Study of the P-type doping properties of ZnS nanocrystals  

Science Conference Proceedings (OSTI)

The paper presents the study of p-type doping properties of ZnS nanocrystals (Ncs) using the local density approximation theory (LDA). Doping with single species of N, P, or As, ZnS nanocrystals are found to have a low-doping concentration and efficiency, ...

Xiying Ma

2011-01-01T23:59:59.000Z

106

Modeling Zn Adsorption and Desorption to Soils Zhenqing Shi1,2  

E-Print Network (OSTI)

, Newark, DE 19717, U.S.A. Keywords: adsorption, desorption, kinetics, soil organic matter, WHAM 1 was considered as the sole adsorbent for Zn binding to the tested soils (1). The mechanistic model WHAM was used to obtain Kp1 and Kp2 at various reaction conditions. In WHAM V calculations (3), Zn can bind to either

Sparks, Donald L.

107

Atomic layer deposition of ZnO on ultralow-density nanoporous silica aerogel monoliths  

Science Conference Proceedings (OSTI)

We report on atomic layer deposition of an ? 2 -nm-thick ZnO layer on the inner surface of ultralow-density ( ? 0.5 % of the full density) nanoporoussilica aerogel monoliths with an extremely large effective aspect ratio of ? 10 5 (defined as the ratio of the monolith thickness to the average pore size). The resultant monoliths are formed by amorphous- SiO 2 core/wurtzite-ZnO shell nanoparticles which are randomly oriented and interconnected into an open-cell network with an apparent density of ? 3 % and a surface area of ? 10 0 m 2 g ? 1 . Secondary ion mass spectrometry and high-resolution transmission electron microscopy imaging reveal excellent uniformity and crystallinity of ZnO coating. Oxygen K -edge and Zn L 3 -edge soft x-ray absorption near-edge structure spectroscopy shows broadened O p - as well as Zn s - and d -projected densities of states in the conduction band.

S. O. Kucheyev; J. Biener; Y. M. Wang; T. F. Baumann; K. J. Wu; T. van Buuren; A. V. Hamza; J. H. Satcher Jr.; J. W. Elam; M. J. Pellin

2005-01-01T23:59:59.000Z

108

Role of indium in highly crystalline ZnO thin films  

Science Conference Proceedings (OSTI)

Zinc oxide and indium doped zinc oxide (ZnO:In) transparent conducting thin films were deposited on glass substrates by pulsed DC magnetron sputtering using separate Zn and In targets. The independent control of the In content in ZnO has helped us to explore the role of indium in influencing the oriented (002) growth, crystallinity, conductivity and mobility of the doped films. The lowest resistivity of ZnO:In thin film is 2.73 Multiplication-Sign 10{sup -3} ohm-cm. At the optimal condition of high (002) orientation, ZnO:In films with electrical resistivity of 7.63 Multiplication-Sign 10{sup -3} ohm.cm and mobility of 126.4 cm{sup 2}/V.s are achieved.

Singh, Anil; Chaudhary, Sujeet; Pandya, Dinesh K. [Thin Film Laboratory, Physics Department, Indian Institute of Technology Delhi, New Delhi 110016 (India)

2013-02-05T23:59:59.000Z

109

Development of ZnO:Ga as an Ultrafast Scintillator  

DOE Green Energy (OSTI)

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.

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

2008-12-10T23:59:59.000Z

110

Magnetotransport Properties of High Quality Co:ZnO and Mn:ZnO Single Crystal Pulsed Laser Deposition films: Pitfalls Associated with Magnetotransport on High Resistivity Materials  

SciTech Connect

The electrical resistivity values for a series of pure and doped (Co, Mn, Al) ZnO epitaxial films grown by pulsed laser deposition were measured with equipment designed for determining the DC resistivity of high resistance samples. Room-temperature resistances ranging from 7x10^1 ohms/square to 4x10^8 ohms/square were measured on vacuum-reduced cobalt-doped ZnO, (Al,Co) co-doped ZnO, pure cobalt-doped ZnO, Mn-doped ZnO, and undoped ZnO. Using a four-point collinear geometry with gold spring-pin contacts, resistivities were measured from 295 to 5 K for resistances of < ~10^12 ohms/square. In addition, magnetoresistance (MR) and Hall effect were measured as a function of temperature for select samples. Throughout the investigation, samples were also measured on commercially available instrumentation with good agreement. The challenges of transport measurements on high resistivity samples are discussed, along with some offered solutions to those challenges.

McCloy, John S.; Ryan, Joseph V.; Droubay, Timothy; Kaspar, Tiffany C.; Chambers, Scott A.; Look, David

2010-06-01T23:59:59.000Z

111

Carbothermal reduction growth of ZnO nanostructures on sapphire-comparisons between graphite and activated charcoal powders  

Science Conference Proceedings (OSTI)

Zinc oxide (ZnO) nanostructures were grown by the vapour phase transport (VPT) method on a-plane sapphire substrates via carbothermal reduction of ZnO powders with various carbon powders. Specifically, graphite powder and activated charcoal powder (of ... Keywords: Growth, Nanostructures, ZnO

M. Biswas; E. McGlynn; M. O. Henry

2009-02-01T23:59:59.000Z

112

AUTONOMOUS OM USTION POWERED HOPPING RO OT TE HNOLOGY ...  

POTENTIAL APPLI ATIONS INQUIRY? Energy efficient combustion technology Search & Rescue Missions Space Exploration Law Enforcement & First

113

Effect of heteroboundary spreading on the properties of exciton states in Zn(Cd)Se/ZnMgSSe quantum wells  

Science Conference Proceedings (OSTI)

Exciton states in Zn(Cd)Se/ZnMgSSe quantum wells with different diffusion spreading of interfaces are studied by optical spectroscopy methods. It is shown that the emission spectrum of quantum wells at low temperatures is determined by free excitons and bound excitons on neutral donors. The nonlinear dependence of the stationary photoluminescence intensity on the excitation power density and the biexponential luminescence decay are explained by the neutralization of charged defects upon photoexcitation of heterostructures. With the stationary illumination on, durable (about 40 min) reversible changes in the reflection coefficient near the exciton resonances of quantum wells are observed. It is shown that, along with the shift of exciton levels, the spreading of heteroboundaries leads to three effects: an increase in the excitonphonon interaction, an increase in the energy shift between the emission lines of free and bound excitons, and a decrease in the decay time of exciton luminescence in a broad temperature range. The main reasons for these effects are discussed.

Adiyatullin, A. F., E-mail: bert-sp@yandex.ru; Belykh, V. V.; Kozlovsky, V. I.; Krivobok, V. S., E-mail: krivobok@lebedev.ru; Martovitsky, V. P.; Nikolaev, S. N. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

2012-11-15T23:59:59.000Z

114

Low-cost CdZnTe devices for cascade cell application  

DOE Green Energy (OSTI)

This report describes a research program to develop a low-cost technique for producing Cd{sub 1-x}Zn{sub x}Te devices for cascade solar cell applications. The technique involves a two-stage process for fabricating such devices with a band gap of about 1.7 eV and a transparent contact layer of low-resistivity ZnTe. In the first stage, thin films of Cd, Zn, and Te are deposited in stacked layers as Cd{sub 1-x}An{sub x}Te. The second stage involves hearing and reacting the layers to form the compound. At first, electrodeposition was used for depositing the layers to successfully fabricate Dc{sub 1-x}Zn{sub x}Te thin-film devices. These films were also intrinsically doped with copper. For the first time, transparent ZnTe films of low resistivity were obtained in a two-stage process; preliminary solar cells using films with low Zn content were demonstrated. A second phase of the project involved growing films with higher Zn content (>15%). Such films were grown on CdS-coated substrates for fabricating devices. The effects of the solar-cell processing steps on the Cd{sub 1-x}Zn{sub x}Te and CdS/Cd{sub 1-x}Zn{sub x}Te interfaces were studied; results showed that the nature of the interface depended on the stoichiometry of the Cd{sub 1-x}Zn{sub x}Te thin film. A sharp interface was observed for the CdS/CdTe structures, but the interface became highly diffused as the Zn content in the absorber layer increased above 15%. The interaction between the CdS window layer and the Cd{sub 1-x}Zn{sub x}Te absorber layer was found to result from an exchange reaction between Zn in the absorber layer and the thin CdS film. 14 refs., 10 figs.

Basol, B.M.; Kapur, V.K. (International Solar Electric Technology, Inglewood, CA (USA))

1990-11-01T23:59:59.000Z

115

Effective photoelectric converters of ultraviolet radiation with graded-gap ZnS-based layers  

SciTech Connect

The use of ultrathin ({approx}10 nm) stable p-Cu{sub 1.8}S films as a transparent component of the p-Cu{sub 1.8}S-n-ZnS heterojunction as well as of the graded-gap layers made it possible to obtain effective photoconverters of ultraviolet radiation. The results of examination of the properties of photoactive Cu{sub 1.8}S-ZnS junctions grown on the CdS or CdSe substrates with intermediate graded-gap layers CdS-Zn{sub x}Cd{sub 1-x}S or CdSe-(ZnS){sub x}(CdSe){sub 1-} {sub x}, respectively, are presented. With the correct selection of parameters of the substrates, the graded-gap layers allows one to attain the optimal characteristics of the p-n junction, to realize high electric fields at the Cu{sub 1.8}S-ZnS contact, and to solve the problem of fabrication of the back ohmic contact to ZnS without additional doping of all components of the heterostructure with a foreign impurity. Varying the thickness of a thin ZnS layer, it is possible to control the extension of the space charge in the graded-gap layer and thereby to control the long-wavelength edge of photoconverter sensitivity.

Bobrenko, Yu. N.; Pavelets, S. Yu., E-mail: pavelets@voliacable.com; Pavelets, A. M. [National Academy of Sciences of Ukraine, Lashkarev Institute of Semiconductor Physics (Ukraine)

2009-06-15T23:59:59.000Z

116

Novel ways of depositing ZnTe films by a solution growth technique  

DOE Green Energy (OSTI)

An electrochemical process has been successfully developed for the reproducible deposition of ZnTe and copper-doped ZnTe films suitable as transparent ohmic contacts for CdS/CdTe solar cells. The development of this method and optimization of key processing steps in the fabrication of CdS/CdTe/ZnTe:Cu devices has allowed IEC to achieve cell performance results of FF>70% and {eta} {approximately}10%. Preliminary efforts have indicated that the deposition methods investigated are potentially feasible for the formation of other II-VI compounds for use in polycrystalline thin film solar devices and should be the focus of future work.

Birkmire, R.W.; McCandless, B.E.; Yokimcus, T.A.; Mondal, A. (Delaware Univ., Newark, DE (United States). Inst. of Energy Conversion)

1992-10-01T23:59:59.000Z

117

Excitation density distribution in electron-beam-pumped ZnSe semiconductor lasers  

Science Conference Proceedings (OSTI)

The spatial density distribution of the absorbed energy in ZnSe semiconductor lasers excited by electrons with energies from 2 keV to 1 MeV is calculated by the Monte-Carlo method. Approximate analytic expressions determining the absorbed energy of electrons in ZnSe are presented. The pump power threshold in a semiconductor quantum-well ZnSe structure is experimentally determined. The lasing threshold in such structures is estimated as a function of the electron energy. (active media)

Donskoi, E N; Zalyalov, A N; Petrushin, O N; Savel'ev, Yu A; Tarasov, M D; Shigaev, Yu S [Russian Federal Nuclear Center 'All-Russian Scientific Research Institute of Experimental Physics', Sarov, Nizhnii Novgorod Region (Russian Federation); Zhdanova, E V; Zverev, M M; Peregudov, D V [Moscow State Institute of Radio-Engineering, Electronics and Automation (Technical University), Moscow (Russian Federation); Ivanov, S V; Sedova, I V; Sorokin, S V [A.F. Ioffe Physico-Technical Institute, Russian Academy of Sciences, St. Petersburg (Russian Federation)

2008-12-31T23:59:59.000Z

118

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

SciTech Connect

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.

David P. Norton; Stephen Pearton; Fan Ren

2007-09-30T23:59:59.000Z

119

DD3, A New Approach to Make ZnO-Cu - Programmaster.org  

Science Conference Proceedings (OSTI)

For example, solar power conversion efficiency of 1.2% was obtained with ... Such heterojuction solar cells display a high (>80%) quantum efficiency of ..... R4, Control of ZnO Epitaxial Growth via Focused Ion Beam Induced Damage in ...

120

AA10, Evolution and Growth of Nanostructures on ZnO with Staged ...  

Science Conference Proceedings (OSTI)

Indeed, Zn interstitials are calculated to be fast diffusers with migration barriers of 0.57 eV [1]. The characteristic patterns of rays or trenches extending away from ...

Note: This page contains sample records for the topic "zn zurn ot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Sonochemical synthesis of Er3+-doped ZnO nanospheres with enhanced upconversion photoluminescence  

Science Conference Proceedings (OSTI)

Er3+-doped ZnO nanospheres have been synthesized via a sonochemical conversion process. The formation mechanism of these nanocrystals is connected with the sonochemical effect of ultrasound irradiation. The as-prepared Er3+ doped ...

Jun Geng, Guang-Hui Song, Jun-Jie Zhu

2012-01-01T23:59:59.000Z

122

AA4, Optical Properties of Gd Implanted ZnO Single Crystals  

Science Conference Proceedings (OSTI)

DD3, A New Approach to Make ZnO-Cu2O Heterojunctions for Solar Cells ... E2, AlGaAs/GaAs/GaN Wafer Fused HBTs with Ar Implanted Extrinsic Collectors.

123

003 Biosynthesis of CdS and ZnS Nanoparticles by Fungi Biomass  

Science Conference Proceedings (OSTI)

Presentation Title, 003 Biosynthesis of CdS and ZnS Nanoparticles by Fungi Biomass. Author(s), Luis Reyes, Idalia Gomez, Teresa Garza. On-Site Speaker ...

124

Facile synthesis of monodisperse ZnO nanocrystals by direct liquid phase precipitation  

Science Conference Proceedings (OSTI)

ZnO nanocrystals can be synthesized by a variety of methods. Among them, only a few nonhydrolytic methods have been successful at low synthesis temperatures in terms of size, crystallinity, morphology and surface-defect control. These methods require ...

Lan Chen; Justin D. Holmes; Sonia Ramírez-García; Michael A. Morris

2011-01-01T23:59:59.000Z

125

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

Science Conference Proceedings (OSTI)

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.

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

126

Preparation of DNA-Functionalised CdSe/ZnS Quantum Dots  

E-Print Network (OSTI)

We functionalised core-shell CdSe/ZnS quantum dots (QDots) with short-chain 3-mercaptopropionic acid (3MPA) to render these nanocrystalline semiconductor water-soluble. The ligand-exchange reaction was significantly improved ...

Pong, Boon Kin

127

Design of Shallow P-Type Dopants in ZnO: Preprint  

DOE Green Energy (OSTI)

This paper describes approaches to lower the acceptor ionization energy in ZnO by codoping acceptors with donor or isovalent atoms and proposes a universal approach to overcome the doping polarity problem for wide-band-gap semiconductors.

Wei, S.-H.; Li, J.; Yan, Y.

2008-05-01T23:59:59.000Z

128

Configurational Entropy and Structure of the Molten NaCl-KCl-ZnCl2 ...  

Science Conference Proceedings (OSTI)

In this context, we examine NaCl-KCl-ZnCl2 molten salts and pay particular attention to characterizing the thermodynamics and structure of these liquids in order ...

129

Development of ZnO Based Light Emitting Diodes and Laser Diodes.  

E-Print Network (OSTI)

??ZnO based homojunction light emitting diode, double heterojunction light emitting diode, embedded heterojunction random laser diode and Fabry-Perot nanowire laser devices were fabricated and characterized.… (more)

Kong, Jieying

2012-01-01T23:59:59.000Z

130

Realization of low resistive p-ZnO thin film by Al-As codoping  

Science Conference Proceedings (OSTI)

Al-As codoping into ZnO has been proposed to realize low resistive and stable p-ZnO thin film by RF magnetron sputtering. Al-As codoping has been achieved by As back diffusion from GaAs substrate and sputtering Al doped ZnO target. Hall measurements showed that the hole concentration increases with the increase of Al concentration from 10{sup 15} to 10{sup 20} cm{sup -3}. Among the grown films, 1 at% Al doped ZnO: As showed low resistivity (3.5x10{sup -2}{Omega}cm) with high hole concentration. X-ray diffraction shows that all the films are crystallized in wurtzite structure with (002) preferential orientation. The diffusion of As atoms from the substrate and the presence of dopants in the film have been confirmed by Rutherford ford back scattering and energy dispersive spectroscopy analysis, respectively.

Balakrishnan, L.; Gowrishankar, S.; Gopalakrishnan, N. [Thin Film Laboratory, Department of Physics, National Institute of Technology, Tiruchirappalli 620015 (India)

2012-06-05T23:59:59.000Z

131

Relative Humidity Sensing Properties Of Cu{sub 2}O Doped ZnO Nanocomposite  

Science Conference Proceedings (OSTI)

In this paper we report application of Cu{sub 2}O doped ZnO composite prepared by solid state reaction route as humidity sensor. Pellet samples of ZnO-Cu{sub 2}O nanocrystalline powders with 2, 5 and 10 weight% of Cu{sub 2}O in ZnO have been prepared. Pellets have been annealed at temperatures of 200-500 deg. C and exposed to humidity. It is observed that as relative humidity increases, resistance of the pellet decreases for the humidity from 10% to 90%. Sample with 5% of Cu{sub 2}O doped in ZnO and annealed at 500 deg. C shows best results with sensitivity of 1.50 M{omega}/%RH. In this case the hysteresis is low and the reproducibility high, making it the suitable candidate for humidity sensing.

Pandey, N. K.; Tiwari, K.; Tripathi, A.; Roy, A.; Rai, A.; Awasthi, P. [Sensors and Materials Research Laboratory, Department of Physics, University Of Lucknow, U.P., Pin-226007 (India)

2009-06-29T23:59:59.000Z

132

Floating Growth of Aligned ZnO Nanowire Arrays on Graphene in ...  

Science Conference Proceedings (OSTI)

The high sensitivity of 1.62 A/W-volt and fast response time ~300 ms obtained represent a significant improvement over ZnO/graphene UV detectors obtained ...

133

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

SciTech Connect

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.

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

134

Conversion mechanism of conductivity of phosphorus-doped ZnO films induced by post-annealing  

SciTech Connect

The effects of post-annealing on conductivity of phosphorus-doped ZnO (PZO) films grown at 500 Degree-Sign C by radio frequency magnetron sputtering are investigated in a temperature ranging from 600 Degree-Sign C to 900 Degree-Sign C. The as-grown PZO exhibits n-type conductivity with an electron concentration of 1.19 Multiplication-Sign 10{sup 20} cm{sup -3}, and keeps n-type conductivity as annealed at 600 Degree-Sign C-700 Degree-Sign C but electron concentration decreases with increasing temperature. However, it converts to p-type conductivity as annealed at 800 Degree-Sign C. Further increasing temperature, it still shows p-type conductivity but the hole concentration decreases. It is found that the P occupies mainly Zn site (P{sub Zn}) in the as-grown PZO, which accounts for good n-type conductivity of the as-grown PZO. The amount of the P{sub Zn} decreases with increasing temperature, while the amount of Zn vacancy (V{sub Zn}) increases from 600 Degree-Sign C to 800 Degree-Sign C but decreases greatly at 900 Degree-Sign C, resulting in that the amount of P{sub Zn}-2V{sub Zn} complex increases with increasing temperature up to 800 Degree-Sign C but decreases above 800 Degree-Sign C. It is suggested that the P{sub Zn}-2V{sub Zn} complex acceptor is responsible for p-type conductivity, and that the conversion of conductivity is due to the change of the amount of the P{sub Zn} and P{sub Zn}-2V{sub Zn} with annealing temperature.

Li, Jichao; Yao, Bin [Key Laboratory of Physics and Technology for Advanced Batteries, Ministry of Education and Department of Physics, Jilin University, Changchun 130023 (China) [Key Laboratory of Physics and Technology for Advanced Batteries, Ministry of Education and Department of Physics, Jilin University, Changchun 130023 (China); State Key Laboratory of Superhard Materials and College of Physics, Jilin University, Changchun 130023 (China); Li, Yongfeng [Key Laboratory of Physics and Technology for Advanced Batteries, Ministry of Education and Department of Physics, Jilin University, Changchun 130023 (China)] [Key Laboratory of Physics and Technology for Advanced Batteries, Ministry of Education and Department of Physics, Jilin University, Changchun 130023 (China); Ding, Zhanhui; Xu, Ying [State Key Laboratory of Superhard Materials and College of Physics, Jilin University, Changchun 130023 (China)] [State Key Laboratory of Superhard Materials and College of Physics, Jilin University, Changchun 130023 (China); Zhang, Ligong; Zhao, Haifeng; Shen, Dezhen [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, No. 3888 Dongnanhu Road, Changchun 130033 (China)] [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, No. 3888 Dongnanhu Road, Changchun 130033 (China)

2013-05-21T23:59:59.000Z

135

Atomic Layer Deposition of ZnO on Multi-walled Carbon Nanotubes and Its Use for Synthesis of CNT–ZnO Heterostructures  

E-Print Network (OSTI)

at the atomic level. It has been applied to deposit a variety of materials including oxides and metals on various nonplanar high-aspect-ratio substrates [8]. ALD on CNTs has been an interesting topic, but there are rela- tively few reports compared to ALD... at *560 and *630 nm, a feature similar to the PL of ZnO nanowire reported by Fan et al. [21]. Emission in the green spectra range is commonly observed in bulk and nanostructure ZnO and the origin is still under debate [22, 23]. The orange–red emission...

2010-08-07T23:59:59.000Z

136

Synthesis and optical properties of hierarchical pure ZnO nanostructures  

SciTech Connect

We report the catalyst-free synthesis of hierarchical pure ZnO nanostructures with 6-fold structural symmetry by two-step thermal evaporation process. At the first step, the hexagonal-shaped nanowires consisting of a great deal of Zn and little oxide were prepared via the layer-by-layer growth mechanism; and at the second step, hierarchical pure ZnO nanostructures were synthesized by evaporating the Zn source on the basis of the step-one made substrate. Scanning electron microscopy, transmission electron microscope images, and the corresponding selected area electron diffraction pattern have been utilized to reveal the screw dislocation growth mechanism, through which the single crystal ZnO nanorods are epitaxially grown from the side-wall of central axial nanowires. Raman and photoluminescence spectra further indicate that, for the hierarchical ZnO nanostructures, the ultraviolet peak is related to the free exciton recombination, while the oxygen vacancies and high surface-to-volume ratio are responsible for the strong green peak emission.

Fan, D.H.; Zhu, Y.F. [Laboratory of Condensed Matter Spectroscopy and Opto-Electronic Physics, Department of Physics, Shanghai Jiao Tong University, 1954 Hua Shan Road, Shanghai 200030 (China); Shen, W.Z. [Laboratory of Condensed Matter Spectroscopy and Opto-Electronic Physics, Department of Physics, Shanghai Jiao Tong University, 1954 Hua Shan Road, Shanghai 200030 (China)], E-mail: wzshen@sjtu.edu.cn; Lu, J.J. [Laboratory of Condensed Matter Spectroscopy and Opto-Electronic Physics, Department of Physics, Shanghai Jiao Tong University, 1954 Hua Shan Road, Shanghai 200030 (China)

2008-12-01T23:59:59.000Z

137

Long Electron-Hole Separation of ZnO-CdS Core-Shell Quantum Dots  

DOE Green Energy (OSTI)

The tunability of electronic and optical properties of semiconductor nanocrystal quantum dots (QDs) has been an important subject in nanotechnology. While control of the emission property of QDs in wavelength has been studied extensively, control of the emission lifetime of QDs has not been explored in depth. In this report, ZnO-CdS core-shell QDs were synthesized in a two-step process, in which we initially synthesized ZnO core particles, and then stepwise slow growth of CdS shells followed. The coating of a CdS shell on a ZnO core increased the exciton lifetime more than 100 times that of the core ZnO QD, and the lifetime was further extended as the thickness of shell increased. This long electron-hole recombination lifetime is due to a unique staggered band alignment between the ZnO core and CdS shell, so-called type II band alignment, where the carrier excitation holes and electrons are spatially separated at the core and shell, and the exciton lifetime becomes extremely sensitive to the thickness of the shell. Here, we demonstrated that the emission lifetime becomes controllable with the thickness of the shell in ZnO-CdS core-shell QDs. The longer excitonic lifetime of type II QDs could be beneficial in fluorescence-based sensors, medical imaging, solar cells photovoltaics, and lasers.

Xu, F.; Volkov, V.; Zhu, Y.; Bai, H.; Rea, A.; Valappil, N.V.; Su, W.; Gao, X.; Kuskovsky, I.L.; Matsui, H.

2009-10-19T23:59:59.000Z

138

Microwave-assisted low temperature synthesis of wurtzite ZnS quantum dots  

SciTech Connect

In this work we report, for the first time, on microwave assisted synthesis of wurtzite ZnS quantum dots (QDs) in controlled reaction at temperature as low as 150 Degree-Sign C. The synthesis can be done in different microwave absorbing solvents with multisource or single source precursors. The QDs are less than 3 nm in size as characterized by transmission electron microscopy (TEM) using selected area electron diffraction (SAED) patterns to confirm the wurtzite phase of ZnS QDs. The optical properties were investigated by UV-Vis absorption which shows blue shift in absorption compared to bulk wurtzite ZnS due to quantum confinement effects. The photoluminescence (PL) spectra of QDs reveal point defects related emission of ZnS QDs. - Graphical abstract: Microwave assisted synthesis of wurtzite ZnS quantum dots (QDs) have been achieved in controlled reaction at temperature as low as 150 Degree-Sign C. The synthesis was performed in different microwave absorbing solvents with multisource or single source precursors for very short reaction periods due to effective heating with microwaves. Highlights: Black-Right-Pointing-Pointer Wurtzite a high temperature phase of ZnS was synthesized at low temperature. Black-Right-Pointing-Pointer Low temperature synthesis was possible because of the use of microwave absorbing solvents. Black-Right-Pointing-Pointer Capping agent was used to control the size of Quantum Dots. Black-Right-Pointing-Pointer Two different systems were developed using single molecular precursor and multisource precursors.

Shahid, Robina, E-mail: rkhan@kth.se [Division of Functional Materials, Royal Institute of Technology (KTH), 16440, Kista, Stockholm (Sweden); Toprak, Muhammet S., E-mail: toprak@kth.se [Division of Functional Materials, Royal Institute of Technology (KTH), 16440, Kista, Stockholm (Sweden); Muhammed, Mamoun [Division of Functional Materials, Royal Institute of Technology (KTH), 16440, Kista, Stockholm (Sweden)

2012-03-15T23:59:59.000Z

139

One-Step Growth of Ge doped ZnO Tubes by Thermal Evaporation  

Science Conference Proceedings (OSTI)

In this paper we report a simple thermal evaporation technique (horizontal tube furnace) to grow the bulk-quantity of germanium (Ge) doped zinc oxide (ZnO) tubes on the Si substrate by using one-step thermal evaporation of a mixed powder of Ge and ZnO. The microstructure and optical properties of the Ge doped ZnO tubes have been investigated by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction, photoluminescence (PL) spectrometer and Raman spectrometer. The investigation of structural properties indicated that the structures consist of bulk quantities of cylindrical rod and tube with diameter around 1micron. EDX reveals that the tube structures have Ge, Zn and O{sub 2} compositions and XRD analysis indicated the product is mainly composed of Ge, zinc germanium oxide (Zn{sub 2}GeO{sub 4}) and small proportion of ZnO. Room temperature photoluminescence (PL) spectrum shows broad emission peaks around 400 nm, opening up a route to potential applications in future optoelectronic devices. Raman measurement also measured at room temperature for these tubes.

Jumidali, M. M. [School of Physics, Universiti Sains Malaysia (USM), 11800 Minden, Penang (Malaysia); Faculty of Applied Science, Universiti Teknologi MARA, 13500 Penang (Malaysia); Hashim, M. R. [School of Physics, Universiti Sains Malaysia (USM), 11800 Minden, Penang (Malaysia); Sulieman, K. M. [Faculty of Applied Science, Universiti Teknologi MARA, 13500 Penang (Malaysia)

2011-03-30T23:59:59.000Z

140

Surface Enthalpies of Nanophase ZnO with Different Morphologies  

SciTech Connect

A direct calorimetric measurement of the dependence of the surface enthalpy of nanophase ZnO on morphology is reported. Nanoparticles, nanoporous composites, nanorods, and nanotetrapods were prepared with various sizes and their surface enthalpies were derived from their drop solution enthalpies in molten sodium molybdate. Water adsorption calorimetry for nanoparticles and nanorods was carried out to characterize the stabilization effect of surface hydration. The surface enthalpies of hydrated surfaces for nanoparticles, nanoporous composites, nanorods and nanotetrapods are 1.31±0.07, 1.42±0.21, 5.19±0.56, and 5.77±2.50 J/m2, respectively, while those of the anhydrous surfaces are 2.55±0.23, 2.74±0.16, 6.67±0.56, and 7.28±2.50 J/m2. The surface enthalpies of nanoparticles are the same as those of nanoporous composites, and are much lower than those of nanorods and nanotetrapods, which are also close to each other. The dependence of surface enthalpy on morphology is discussed in terms of exposed surface structures. This is the first time that calorimetry on nanocrystalline powders bas been able to detect differences in surface energetics of materials having different morphologies.

Zhang, Peng; Xu, Fen; Navrotsky, Alexandra; Lee, Jong Soo; Kim, Sangtae; Liu, Jun

2007-11-13T23:59:59.000Z

Note: This page contains sample records for the topic "zn zurn ot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

DEVELOPMENT OF CdZnTe RADIATION DETECTORS  

Science Conference Proceedings (OSTI)

Cadmium Zinc Telluride (CdZnTe or CZT) is a very attractive material for room-temperature semiconductor detectors because of its wide band-gap and high atomic number. Despite these advantages, CZT still presents some material limitations and poor hole mobility. In the past decade most of the developing CZT detectors focused on designing different electrode configurations, mainly to minimize the deleterious effect due to the poor hole mobility. A few different electrode geometries were designed and fabricated, such as pixelated anodes and Frisch-grid detectors developed at Brookhaven National Lab (BNL). However, crystal defects in CZT materials still limit the yield of detector-grade crystals, and, in general, dominate the detector's performance. In the past few years, our group's research extended to characterizing the CZT materials at the micro-scale, and to correlating crystal defects with the detector's performance. We built a set of unique tools for this purpose, including infrared (IR) transmission microscopy, X-ray micro-scale mapping using synchrotron light source, X-ray transmission- and reflection-topography, current deep level transient spectroscopy (I-DLTS), and photoluminescence measurements. Our most recent work on CZT detectors was directed towards detailing various crystal defects, studying the internal electrical field, and delineating the effects of thermal annealing on improving the material properties. In this paper, we report our most recent results.

BOLOTNIKOV, A.; CAMARDA, G.; HOSSAIN, A.; KIM, K.H.; YANG, G.; GUL, R.; CUI, Y.; AND JAMES, R.B.

2011-10-23T23:59:59.000Z

142

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

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.

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

143

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

Science Conference Proceedings (OSTI)

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.

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

144

Investigation of ZnO nanopillars fabrication in a new Thomas Swan close coupled showerhead MOCVD reactor  

Science Conference Proceedings (OSTI)

Self-organized ZnO nanopillars were grown on a-plane Al"2O"3 in a vertical MOCVD reactor using diethylzinc and N"2O as precursors. This is the very first Thomas Swan reactor that is specially designed for the growth of ZnO and GaN. The influence of different ... Keywords: MOCVD, MOVPE, Nanopillars, Zincoxide, ZnO

A. Behrends; A. Bakin; A. Waag

2009-02-01T23:59:59.000Z

145

Enhanced electron transport in dye-sensitized solar cells using short ZnO nanotips on a rough metal anode.  

DOE Green Energy (OSTI)

Many efforts have been directed toward the enhancement of electron transport in dye-sensitized solar cells (DSSC) using one-dimensional nanoarchitectured semiconductors. However, the improvement resulting from these ordered 1-D nanostructured electrodes is often offset or diminished by the deterioration in other device parameters intrinsically associated with the use of these 1-D nanostructures, such as the two-sided effect of the length of the nanowires impacting the series resistance and roughness factor. In this work, we mitigate this problem by allocating part of the roughness factor to the collecting anode instead of imparting all the roughness factors onto the semiconductor layer attached to the anode. A microscopically rough Zn microtip array is used as an electron-collecting anode on which ZnO nanotips are grown to serve as the semiconductor component of the DSSC. For the same surface roughness factor, our Zn-microtip|ZnO-nanotip DSSC exhibits an enhanced fill factor compared with DSSCs that have ZnO nanowires supported by a planar anode. In addition, the open-circuit voltage of the Zn-microtip|ZnO-nanotip DSSC is also improved due to a favorable band shift at the Zn-ZnO interface, which raises the Fermi level of the semiconductor and consequently enlarges the energy gap between the quasi-Fermi level of ZnO and the redox species. With these improvements, the overall efficiency becomes 1.4% with an open-circuit voltage of 770 mV, while the surface roughness factor of ZnO is approximately 60. Electrochemical impedance spectroscopic study reveals that the electron collection time is much shorter than the electron lifetime, suggesting that fast electron collection occurs in our device due to the significantly reduced electron collection distance along the short ZnO nanotips. The overall improvement demonstrates a new approach to enhance the efficiency of dye-sensitized solar cells.

Yang, Z.; Xu, T.; Ito, Y.; Welp, U.; Kwok, W. K.; Materials Science Division; Northern Illinois Univ.

2009-10-22T23:59:59.000Z

146

Flexible Zn2SnO4/MnO2 Core/Shell Nanocable-Carbon Microfiber ...  

Science Conference Proceedings (OSTI)

Presentation Title, Flexible Zn2SnO4/MnO2 Core/Shell Nanocable-Carbon Microfiber Hybrid Composites for High-Performance Supercapacitor Electrodes.

147

Effects of Hydrogen Content in Sputtering Ambient on ZnO:A1 Electrical Properties  

Science Conference Proceedings (OSTI)

ZnO-based transparent conducting oxide (TCO) thin films have received increased attention recently because of their potential to reduce production costs compared to those of the prevalent TCO indium tin oxide (ITO). Undoped ZnO and ZnO:Al (0.1, 0.2, 0.5, 1, and 2 wt% Al2O3) polycrystalline films were deposited by RF magnetron sputtering. Controlled incorporation of H2 and O2 in the Ar sputtering ambient was investigated. Though optimal substrate temperature was found to be 200 C for films grown in 100% Ar, the addition of H2 permits improved electrical performance for room-temperature depositions. Temperature-dependent Hall data suggest that ionized impurity and acoustic phonon scattering dominate at high and intermediate carrier concentration levels, respectively, with evidence of temperature-activated transport at the lowest levels. Lightly doped ZnO:Al demonstrates reduced infrared absorption compared to the standard 2 wt%-doped ZnO:Al, which may be beneficial to device performance.

Duenow, J. N.; Gessert, T. A.; Wood, D. M.; Young, D. L.; Coutts, T. J.

2008-01-01T23:59:59.000Z

148

Highly ordered Zn-doped mesoporous silica: An efficient catalyst for transesterification reaction  

Science Conference Proceedings (OSTI)

Designing highly ordered material with nanoscale periodicity is of great significance in the field of solid state chemistry. Herein, we report the synthesis of highly ordered 2D-hexagonal mesoporous zinc-doped silica using a mixture of anionic and cationic surfactants under hydrothermal conditions. Powder XRD, N{sub 2} sorption, TEM analysis revealed highly ordered 2D-hexagonal arrangements of the pores with very good surface area (762 m{sup 2} g{sup -1}) in this Zn-rich mesoporous material. Chemical analysis shows very high loading of zinc (ca. 12.0 wt%) in the material together with retention of hexagonal pore structure. Interestingly, high temperature calcination resulted into zinc silicate phase, unlike any ZnO phase, which otherwise is expected under heat treatments. High surface area together with Zn loading in this mesoporous material has been found useful for the catalytic activity of the materials in the acid-catalyzed transesterification reactions of various esters under mild liquid phase conditions. - Graphical abstract: Zn-rich 2D-hexagonal mesoporous materials are synthesized hydrothermally, which show very good catalytic activity in the transesterification reaction under mild liquid phase reaction conditions. Highlights: > Zn-rich 2D-hexagonal mesoporous silica. > High surface area material. > Efficient catalyst in liquid phase transesterification reaction. > Biodiesel production.

Pal, Nabanita; Paul, Manidipa [Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India); Bhaumik, Asim, E-mail: msab@iacs.res.in [Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India)

2011-07-15T23:59:59.000Z

149

Characteristics of Dispersed ZnO-Folic acid Conjugate in Aqueous Medium  

E-Print Network (OSTI)

The focus of this article is based on the aqueous dispersed state properties of inorganic ZnO nanoparticles (average size lessthan or equal to 4 nm), their surface modification and bio-functionalization with folic acid at physiological pH ~ 7.5, suitable for bio-imaging and targeted therapeutic application. While TEM studies of the ZnO nano-crystallites have been performed to estimate their size and morphology in dry state, the band gap properties of the freshly prepared samples, the hydrodynamic size in aqueous solution phase and the wide fluorescence range in visible region have been investigated to establish the fact that the sol is particularly suitable for the bio-medical purpose in the aqueous dispersed state. Key words: ZnO nanoparticle; folic acid; band gap; hydrodynamic size; fluorescence.

Sreetama Dutta; Bichitra Nandi Ganguly

2013-12-04T23:59:59.000Z

150

Laser-assisted sol-gel growth and characteristics of ZnO thin films  

SciTech Connect

ZnO thin films were grown on Si(100) substrates by a sol-gel method assisted by laser beam irradiation with a 325 nm He-Cd laser. In contrast to conventional sol-gel ZnO thin films, the surface morphology of the laser-assisted sol-gel thin films was much smoother, and the residual stress in the films was relaxed by laser irradiation. The luminescent properties of the films were also enhanced by laser irradiation, especially, by irradiation during the deposition and post-heat treatment stages. The incident laser beam is thought to play several roles, such as annihilating defects by accelerating crystallization during heat treatment, enhancing the surface migration of atoms and molecules, and relaxing the ZnO matrix structure during crystallization.

Kim, Min Su; Kim, Soaram [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Gimhae 621-749 (Korea, Republic of); Leem, Jae-Young [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Gimhae 621-749 (Korea, Republic of); Department of Nano Engineering, Inje University, Gimhae 621-749 (Korea, Republic of)

2012-06-18T23:59:59.000Z

151

Optical Properties of MEH-PPV Thin Films Containing ZnO Nanoparticles  

Science Conference Proceedings (OSTI)

Thin films of poly [2-methoxy-5(2'-ethyl hexyloxy)-phenylene vinylene](MEH-PPV) containing different weight percent of ZnO nanoparticles were deposited by spin coating from THF solutions and their optical properties were investigated. Optical characterization of the nanocomposite thin films were performed by Ultraviolet-Visible Spectrophotometer (UV-Vis) and Photoluminescence Spectrometer while the thickness of the thin films was measured by using Surface Profiler. The UV-Vis absorption spectra of MEH-PPV: ZnO films showed a small red shift as compared with pure MEH-PPV. Similarly, a small red shift was found in PL emission spectra with increasing the content of ZnO nanoparticles.

Zayana, N. Y. [NANO-SciTech Center (NST), Institute of Science, Universiti Teknologi MARA, 40450 Shah Alam (Malaysia); Shariffudin, S. S. [NANO- ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA, 40450 Shah Alam (Malaysia); Jumali, N. S.; Shaameri, Z.; Hamzah, A. S. [Organic Synthesis Research Laboratory, Institute of Science, Universiti Teknologi MARA, 40450 Shah Alam (Malaysia); Rusop, M. [NANO-SciTech Center (NST), Institute of Science, Universiti Teknologi MARA, 40450 Shah Alam (Malaysia); NANO- ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA, 40450 Shah Alam (Malaysia)

2011-05-25T23:59:59.000Z

152

Luminescence of CdSe/ZnS quantum dots infiltrated into an opal matrix  

SciTech Connect

The effect of the photonic band gap in the photonic crystal, the synthesized SiO{sub 2} opal with embedded CdSe/ZnS quantum dots, on its luminescence in the visible spectral region is studied. It is shown that the position of the photonic band gap in the luminescence and reflectance spectra for the infiltrated opal depends on the diameter of the constituent nanospheres and on the angle of recording the signal. The optimal conditions for embedding the CdSe/ZnS quantum dots from the solution into the opal matrix are determined. It is found that, for the opal-CdSe/ZnS nanocomposites, the emission intensity decreases and the luminescence decay time increases in the spatial directions, in which the spectral positions of the photonic band gap and the luminescence peak of the quantum dots coincide.

Gruzintsev, A. N. [Russian Academy of Sciences, Institute of Microelectronics Technology and Ultra-High-Purity Materials (Russian Federation)], E-mail: gran@ipmt-hpm.ac.ru; Emelchenko, G. A.; Masalov, V. M. [Russian Academy of Sciences, Institute of Solid State Physics (Russian Federation); Yakimov, E. E. [Russian Academy of Sciences, Institute of Microelectronics Technology and Ultra-High-Purity Materials (Russian Federation); Barthou, C.; Maitre, A. [Institut des NanoSciences (France)

2009-02-15T23:59:59.000Z

153

Field emission behavior of vertically aligned ZnO nanowire planar cathodes  

Science Conference Proceedings (OSTI)

A field emission (FE) study by scanning anode field emission microscopy was performed to evaluate the FE properties of vertically aligned zinc oxide (ZnO) nanowire arrays electrodeposited on a plane conductive surface. The specific FE behaviors of the cathode observed experimentally are (1) a turn-on macroscopic field of about 6 V/{mu}m for a FE current density J{sub FE} 5 x 10{sup -4} A/cm{sup 2}, (2) a stable FE characteristics for 5 x 10{sup -4} Fowler-Nordheim plot and the presence of a Zn enriched surface was assumed in considering the possibility of important modifications of the crystallography and charge transfers at the surface of ZnO nanowires during the application of the strong electric field required for FE.

Semet, V.; Binh, Vu Thien [University of Lyon 1, Equipe Emission Electronique, LPMCN - UMR CNRS, Villeurbanne 69622 (France); Pauporte, Th. [LECIME, UMR7575, ENSCP-CNRS, 11 rue P. et M. Curie, 75231 Paris Cedex 05 (France); Joulaud, L.; Vermersch, F. J. [Saint Gobain Recherche, Aubervilliers 93303 (France)

2011-03-01T23:59:59.000Z

154

High performance thin film transistor with cosputtered amorphous Zn-In-Sn-O channel: Combinatorial approach  

SciTech Connect

Thin film transistors with a channel of Zn-In-Sn-O were fabricated via a combinatorial rf sputtering method. It was found that the role of the In atoms is to enhance the mobility and to shift the threshold voltage (V{sub th}) negatively. On the other hand, the Sn fraction is critical for improving the overall trap density including the density-of-states of the bulk channel layer and the interfacial trap density at the ZnInSnO interface. The optimized transistor was obtained at a compositional ratio of Zn:In:Sn=40:20:40, which exhibited an excellent subthreshold gate swing of 0.12 V/decade, V{sub th} of -0.4 V, and high I{sub on/off} ratio of >10{sup 9} as well as a high field-effect mobility of 24.6 cm{sup 2}/V s.

Ryu, Min Ki; Yang, Shinhyuk; Park, Sang-Hee Ko; Hwang, Chi-Sun [Transparent Electronics Team, ETRI, Daejeon 305-700 (Korea, Republic of); Jeong, Jae Kyeong [Department of Materials Science and Engineering, Inha University, 253 Yonghyun-Dong, Nam-Gu, Incheon 402-751 (Korea, Republic of)

2009-08-17T23:59:59.000Z

155

Band offsets in HfO{sub 2}/InGaZnO{sub 4} heterojunctions  

SciTech Connect

The valence band discontinuity ({Delta}E{sub V}) of sputter deposited HfO{sub 2}/InZnGaO{sub 4} (IGZO) heterostructures was obtained from x-ray photoelectron spectroscopy measurements. The HfO{sub 2} exhibited a bandgap of 6.07 eV from absorption measurements. A value of {Delta}E{sub V} = 0.48 {+-} 0.025 eV was obtained by using the Ga 2p{sub 3/2}, Zn 2p{sub 3/2}, and In 3d{sub 5/2} energy levels as references. This implies a conduction band offset {Delta}E{sub C} of 2.39 eV in HfO{sub 2}/InGaZnO{sub 4} heterostructures and a nested interface band alignment.

Cho, Hyun [Department of Nanomechatronics Engineering, Pusan National University, Gyeongnam 627-706 (Korea, Republic of); Douglas, E. A.; Gila, B. P.; Craciun, V.; Lambers, E. S.; Pearton, S. J. [Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611 (United States); Ren Fan [Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611 (United States)

2012-01-02T23:59:59.000Z

156

Photoluminescence spectral study of single CdSe/ZnS Colloidal Nanocrystals in Poly(methyl methacrylate) and Quantum Dots molecules  

E-Print Network (OSTI)

of the CdSe/ZnS nanocrystals . . . . . . . .D. CdSe/ZnS NCs in negative photon resist SU-line shapes of single CdSe VI Optical characterization of

Shen, Yaoming

2008-01-01T23:59:59.000Z

157

Growth study of nonpolar Zn{sub 1-x}Mg{sub x}O epitaxial films on a-plane bulk ZnO by plasma-assisted molecular beam epitaxy  

Science Conference Proceedings (OSTI)

Nonpolar Zn{sub 1-x}Mg{sub x}O epitaxial films were grown by plasma-assisted molecular beam epitaxy on a-plane ZnO substrates. A smooth surface morphology was accomplished under oxygen-rich growth conditions. The benefits of the use of ZnO substrates on the structural properties are reflected by a low-density of threading dislocations. Furthermore, no indications for the generation of basal plane stacking faults are found. The pseudomorphic growth on a-plane ZnO substrates efficiently locks the epitaxial Zn{sub 1-x}Mg{sub x}O films to the wurtzite structure up to x = 0.25. The Mg concentration is not constant and increases with larger thickness. The optical properties reflect the influence of alloy disorder.

Laumer, Bernhard [Walter Schottky Institut and Physics Department, Technische Universitaet Muenchen, Am Coulombwall 4, 85748 Garching (Germany); I. Physikalisches Institut, Justus-Liebig-Universitaet Giessen, Heinrich-Buff-Ring 16, 35392 Giessen (Germany); Schuster, Fabian; Stutzmann, Martin [Walter Schottky Institut and Physics Department, Technische Universitaet Muenchen, Am Coulombwall 4, 85748 Garching (Germany); Bergmaier, Andreas; Dollinger, Guenther [Universitaet der Bundeswehr Muenchen, Fakultaet fuer Luft- und Raumfahrttechnik, Werner-Heisenberg-Weg 39, 85577 Neubiberg (Germany); Vogel, Stephen; Gries, Katharina I.; Volz, Kerstin [Philipps-Universitaet, Material Sciences Center-Structure and Technology Research Laboratory and Faculty of Physics, Hans-Meerwein-Strasse, 35032 Marburg (Germany); Eickhoff, Martin [I. Physikalisches Institut, Justus-Liebig-Universitaet Giessen, Heinrich-Buff-Ring 16, 35392 Giessen (Germany)

2012-09-17T23:59:59.000Z

158

Characteristics of ZnO nanostructures produced with [DMIm]BF{sub 4} using ultrasonic radiation  

Science Conference Proceedings (OSTI)

Great interests in metallic oxides have emerged because of the promising properties of these materials for various applications such as solar cells and sensors. ZnO nanostructures with different morphologies were successfully synthesized from Zn(CH{sub 3}COO){sub 2} Bullet 2H{sub 2}O, NaOH and room temperature ionic liquid (RTIL) 1-decyl-3-methylimidazolium tetrafluoroborate, [DMIm][BF{sub 4}] with ultrasound irradiation. Parameters such as the effect of sonication time (30, 60 and 90 minutes) and Zn(Ac){sub 2} precursor to [DMIm][BF{sub 4}] ratios of 3:5, 5:5 and 5:3 were investigated. X-ray diffraction patterns revealed that the ZnO nanocrystals were hexagonal zincite crystalline in structure. The band gap energies (E{sub g}) were estimated to be 3.35-3.55 eV from the UV-Visible spectrum. The solution with the highest ratio of Zn was analysed with photoluminescence spectroscopy, which exhibited peaks at 362, 403, 468 and 539 nm, at room temperature. The micrographs of field emission scanning electron microscopy and transmission electron microscopy showed that the synthesis products were spherical (30-60 nm), spindle ({approx}10 Multiplication-Sign 70 nm for width Multiplication-Sign length) and whisker-like (100-200 nm), with their dimensions decreasing systematically with increased sonication time. Chemical compositions were approximated at 1:1 for Zn and O, estimated by electron dispersive x-ray spectrum.

Rahman, I. B. Abdul; Ayob, M. T. M.; Ishak, I. S.; Mohd Lawi, R. L.; Isahak, W. N. R. W.; Hamid, M. H. N. Abd; Othman, N. K.; Radiman, S. [School of Applied Physics, Faculty of Science and Technology (FST), Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor Darul Ehsan (Malaysia); School of Chemistry and Food Technology, Faculty of Science and Technology (FST), Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor Darul Ehsan (Malaysia); School of Applied Physics, Faculty of Science and Technology (FST), Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor Darul Ehsan (Malaysia)

2012-11-27T23:59:59.000Z

159

Effect of solution spray rate on the properties of chemically sprayed ZnO: in thin films  

Science Conference Proceedings (OSTI)

ZnO:In thin filmswere grown from 100 mL of spray solution on glass substrates by chemical spray at Ts = 400°Cusing solution spray rates of 0.5-6.7 mL/min. Zinc acetate and indium(III)chloride were used as Zn and In sources, respectively, ...

Merike Kriisa, Malle Krunks, Erki Kärber, Mart Kukk, Valdek Mikli, Arvo Mere

2013-01-01T23:59:59.000Z

160

Modeling and optimization of the growth rate for ZnO thin films using neural networks and genetic algorithms  

Science Conference Proceedings (OSTI)

The process modeling for the growth rate in pulsed laser deposition (PLD)-grown ZnO thin films was investigated using neural networks (NNets) based on the back-propagation (BP) algorithm and the process recipes was optimized via genetic algorithms (GAs). ... Keywords: Genetic algorithms, Neural networks, PLD, Process modeling, ZnO

Young-Don Ko; Pyung Moon; Chang Eun Kim; Moon-Ho Ham; Jae-Min Myoung; Ilgu Yun

2009-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "zn zurn ot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Synchrotron radiation x-ray absorption fine-structure and Raman studies on CdZnTe ternary alloys  

E-Print Network (OSTI)

The synchrotron radiation (SR) X-ray absorption fine-structure spectroscopy (XAFS) technology has been employed to obtained Zn K-edge absorption spectra for Cd1[subscript 1-x]Zn[subscript x]Te alloy with x = 0.03, 0.10, ...

Becla, Piotr

162

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

E-Print Network (OSTI)

Effect of Pre-Aging on the Microstructure and Strength of Supersaturated AlZnMg Alloys Processed langdon@usc.edu Keywords: Supersaturated AlZnMg alloys, natural aging, Guinier-Prestion zones, Equal on the effect of the combination of natural aging and severe plastic deformation (SPD) produced by Equal

Gubicza, Jenõ

163

Experimental study of alpha-induced reactions on 64Zn for the astrophysical gamma-process  

E-Print Network (OSTI)

For the synthesis of the heavy, proton rich isotopes in the astrophysical gamma-process the precise knowledge of alpha-induced cross sections is of high importance. We have initiated a comprehensive study of the 64Zn+alpha system involving the cross section measurement of different reaction channels as well as the elastic scattering at low, astrophysically relevant energies. In this paper the experimental technique and some preliminary results of the 64Zn(alpha,p)67Ga cross section measurement are presented.

Gy. Gyürky; J. Farkas; Z. Halász; Zs. Fülöp; E. Somorjai; T. Szücs; P. Mohr; A. Wallner

2011-11-02T23:59:59.000Z

164

Spinel ferrite nanocrystals embedded inside ZnO: magnetic, electronic andmagneto-transport properties  

Science Conference Proceedings (OSTI)

In this paper we show that spinel ferrite nanocrystals (NiFe{sub 2}O{sub 4}, and CoFe{sub 2}O{sub 4}) can be texturally embedded inside a ZnO matrix by ion implantation and post-annealing. The two kinds of ferrites show different magnetic properties, e.g. coercivity and magnetization. Anomalous Hall effect and positive magnetoresistance have been observed. Our study suggests a ferrimagnet/semiconductor hybrid system for potential applications in magneto-electronics. This hybrid system can be tuned by selecting different transition metal ions (from Mn to Zn) to obtain various magnetic and electronic properties.

Zhou, Shengqiang; Potzger, K.; Xu, Qingyu; Kuepper, K.; Talut, G.; Marko, D.; Mucklich, A.; Helm, M.; Fassbender, J.; Arenholz, E.; Schmidt, H.

2009-08-21T23:59:59.000Z

165

ZnTe:O phosphor development for x-ray imaging applications  

Science Conference Proceedings (OSTI)

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.

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

166

Bright CdSe quantum dot inserted in single ZnSe nanowires  

Science Conference Proceedings (OSTI)

We report the evidence of CdSe quantum dot (QD) insertion in single defect-free ZnSe nanowire. These nanowires have been grown by molecular beam epitaxy in vapour-liquid-solid growth mode catalysed with gold particles. We developed a two-step process ... Keywords: µPL, Antibunching, CdSe, Correlation measurement, Micro photoluminescence, Polarisation, Single NW, Single QD, Single nanowire, Single nanowire heterostructures, Single quantum dot, TRPL, Time-resolved photoluminescence, Two-step process, ZnSe

A. Tribu; G. Sallen; T. Aichele; C. Bougerol; R. André; J. P. Poizat; S. Tatarenko; K. Kheng

2009-02-01T23:59:59.000Z

167

Photoluminescence in Chemical Vapor Deposited ZnS: insight into electronic defects  

SciTech Connect

Photoluminescence spectra taken from chemical vapor deposited (CVD) ZnS are shown to exhibit sub-band-gap emission bands characteristic of isoelectronic oxygen defects. The emission spectra vary spatially with position and orientation with respect to the major axis of CVD growth. These data suggest that a complex set of defects exist in the band gap of CVD ZnS whose structural nature is highly dependent upon local deposition and growth conditions, contributing to inherent heterogeneity in optical behavior throughout the material.

McCloy, John S.; Potter, B.g.

2013-08-09T23:59:59.000Z

168

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

E-Print Network (OSTI)

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.

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

2013-01-01T23:59:59.000Z

169

Effect of deposition temperature on the crystalline structure and surface morphology of ZnO films deposited on p-Si  

Science Conference Proceedings (OSTI)

Zinc oxide (ZnO) films were deposited on p-Si substrates by sol-gel spin coating method. Zinc acetate dihydrate (ZnAc), 2-methoxyethanol and monoethanolamine (MEA) were used as a starting material, solvent and stabilizer, respectively. The films were ... Keywords: FESEM, ZnO, crystalline structure, deposition temperature, reflectance, sol-gel

Seval Aksoy; Yasemin Caglar; Saliha Ilican; Mujdat Caglar

2010-11-01T23:59:59.000Z

170

Growth and Electronic Properties of GaN/ZnO Solid Solution Nanowires  

Science Conference Proceedings (OSTI)

We have grown single-crystal (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid-solution nanowires using nanostructured ZnGa{sub 2}O{sub 4} precursor prepared by a sol-gel method. From electrical transport measurements in individual nanowire field-effect transistors, we have identified the conduction as n-type and obtained a background carrier density (-10{sup 19} cm{sup -3}) and an electron mobility (-1 cm{sup 2}/V s) that are consistent with chemical disorder and a large number of charge traps, as confirmed by the devices photocurrent response. From the dependence of the device photoresponse on incident light wavelength, we have determined the energy band gap of (Ga{sub 0.88}Zn{sub 0.12})(N{sub 0.88}O{sub 0.12}) to be as much as -0.6 eV lower than that of GaN or ZnO.

Han, W.Q.; Zhang, Y.; Nam, C.-Y.; Black, C.T.; Mendez, E.E.

2010-08-23T23:59:59.000Z

171

ZnO clusters: Laser ablation production and time-of-flight mass spectroscopic study  

Science Conference Proceedings (OSTI)

Zinc oxide clusters have been produced by laser ablation of bulk powder zinc peroxide in vacuum and investigated by time-of-flight mass spectroscopy. Experimental results revealed unpredicted and hitherto unknown (ZnO)"n clusters of enhanced stability ... Keywords: Cluster, Magic number, Time-of-flight mass spectroscopy, Zinc oxide

A. Dmytruk; I. Dmitruk; I. Blonskyy; R. Belosludov; Y. Kawazoe; A. Kasuya

2009-02-01T23:59:59.000Z

172

Optical Properties of p-type ZnO Doped by As Ion Implantation  

Science Conference Proceedings (OSTI)

As-doped p-type ZnO has been achieved by ion implantation. The As-related optical properties were analyzed by using secondary ion mass spectrometry, the Raman scattering, and the photoluminescence experiments. From the I-V measurement, the behavior of rectifying on these samples is confirmed.

Jeong, T.S.; Youn, C.J.; Han, M.S. [Semiconductor Physics Research Center (SPRC), Jeonbuk National University, Jeonju 561-756 (Korea, Republic of); Park, Y. S. [Korea Photonics Technolgy Institute (KOPTI), Gwangju 500-210 (Korea, Republic of); Lee, W.S. [Department of Electrical Engineering, Chosun University, Gangju 501-759 (Korea, Republic of)

2005-06-30T23:59:59.000Z

173

Hydrothermal preparation, characterization and property research of flowerlike ZnO nanocrystals built up by nanoflakes  

Science Conference Proceedings (OSTI)

In the present paper, flowerlike ZnO nanocrystals were successfully synthesized via a simple hydrothermal route in the presence of sodium dodecyl sulfate (SDS), employing Zn(CH{sub 3}COO){sub 2} and KOH as the starting reactants. The phase and morphology of the product were characterized by means of powder X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and select area electron diffraction (SAED). The optical properties of the product were studied. Some factors influencing the morphology of the final product including reaction time, temperature and amounts of the surfactant were discussed. Researches showed that the flowerlike ZnO nanocrystals had a good photo-catalytic activity for degradation of safranine T under 254 nm UV light irradiation. The electrochemical research of the product showed that flowerlike ZnO nanocrystals could promote electron transfers between catechol and the Au electrode. A possible formation mechanism was also suggested based on the results of the experiments.

Ni Yonghong [College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids, Anhui Normal University, Wuhu 241000 (China)], E-mail: niyh@mail.ahnu.edu.cn; Wu Guogen; Zhang Xiaolei; Cao Xiaofeng; Hu Guangzhi; Tao Ali; Yang Zhousheng; Wei Xianwen [College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids, Anhui Normal University, Wuhu 241000 (China)

2008-11-03T23:59:59.000Z

174

Rapid Removal of Mercury from Aqueous Solutions Using Thiol Functionalized Zn-doped Biomagnetite Nanoparticles  

SciTech Connect

The surfaces of Zn-doped biomagnetite nanostructured particles were functionalized with (3-mercaptopropyl)trimethoxysilane (MPTMS) and used as a high-capacity and collectable adsorbent for the removal of Hg(II) from water. Fourier transform infrared spectroscopy (FTIR) confirmed the attachment of MPTMS on the particle surface. The crystallite size of the Zn-doped biomagnetite was {approx}17 nm, and the thickness of the MPTMS coating was {approx}5 nm. Scanning transmission electron microscopy and dynamic light scattering analyses revealed that the particles formed aggregates in aqueous solution with an average hydrodynamic size of 826 {+-} 32 nm. Elemental analyses indicate that the chemical composition of the biomagnetite is Zn{sub 0.46}Fe{sub 2.54}O{sub 4}, and the loading of sulfur is 3.6 mmol/g. The MPTMS-modified biomagnetite has a calculated saturation magnetization of 37.9 emu/g and can be separated from water within a minute using a magnet. Sorption of Hg(II) to the nanostructured particles was much faster than other commercial sorbents, and the Hg(II) sorption isotherm in an industrial wastewater follows the Langmuir model with a maximum capacity of {approx}416 mg/g, indicating two -SH groups bonded to one Hg. This new Hg(II) sorbent was stable in a range of solutions, from contaminated water to 0.5 M acid solutions, with low leaching of Fe, Zn, Si, and S (<10%).

He, Feng [ORNL; Wang, Wei [ORNL; Moon, Ji Won [ORNL; Howe, Jane Y [ORNL; Liang, Liyuan [ORNL; Pierce, Eric M [ORNL

2012-01-01T23:59:59.000Z

175

Cell-Trappable Quinoline-Derivatized Fluoresceins for Selective and Reversible Biological Zn(II) Detection  

E-Print Network (OSTI)

The synthesis and spectroscopic characterization of two new, cell-trappable fluorescent probes for Zn(II) are presented. These probes, 2-(4,5-bis(((6-(2-ethoxy-2-oxoethoxy)quinolin-8-yl)amino)methyl)-6-hydroxy-3-oxo-3H-8 ...

McQuade, Lindsey E.

176

Aqueous synthesis and characterization of CdSe/ZnO core-shell nanoparticles  

Science Conference Proceedings (OSTI)

Core-shell nanomaterials based on CdSe as the core and ZnO as the shell were prepared using an aqueous route involving the use of Cd salt and NaBH4 in reaction with Se to generate CdSe in the presence of thioglycerol (TG) as a stabilizer. ...

B. P. Rakgalakane; M. J. Moloto

2011-01-01T23:59:59.000Z

177

Exciton spectroscopy on single CdSe/ZnSe quantum dot photodiodes  

Science Conference Proceedings (OSTI)

We have investigated the properties of neutral and charged excitons in single CdSe/ZnSe QD photodiodes by @m-photoluminescence spectroscopy. By applying a bias voltage, we have been able to control the number of electrons in a single QD by shifting the ... Keywords: CdSe quantum dots, Photodiode, Stark effect

S. Michaelis de Vasconcellos; A. Pawlis; C. Arens; M. Panfilova; A. Zrenner; D. Schikora; K. Lischka

2009-02-01T23:59:59.000Z

178

Optimization of Conductivity and Transparency in Amorphous In-Zn-O Transparent Conductors: Preprint  

DOE Green Energy (OSTI)

Amorphous mixed metal oxide TCOs are of increasing interest due to the excellent opto-electronic properties and smoothness (RRMS < 0.5 nm) obtained for sputtered films deposited at less than 100 ..deg..C. Here, we have investigated the combined materials phase space of oxygen stoichiometry and metals composition (In:Zn ratio) and made two key discoveries.

Perkins, J.; Berry, J.; van Hest, M.; Alleman, J.; Dabney, M.; Gedvilas, L.; Ginley, D. S.; Leenheer, A.; O'Hayre, R.

2008-05-01T23:59:59.000Z

179

ZnSe nanorods prepared in hydroxide-melts and their application as a humidity sensor  

Science Conference Proceedings (OSTI)

We have synthesized the crystalline ZnSe nanorods for the first time using the molten hydroxides as reaction solvent in the absence of organic dispersant or capping agents. The products are characterized by X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy. The diameters of ZnSe nanorods are about 200-300 nm, and the lengths are about 1-2 {mu}m. Humidity sensors based on ZnSe nanorods are fabricated and their responsiveness to humidity on static and dynamic testing are investigated. The change of resistance is about three orders of magnitude as the relative humidity increases from 20% to 85%. The response time and recovery time is 50 s and 81 s versus the changes of relative humidity from 20% to 85% and from 85% to 20%, respectively. Our sensor offers higher sensitivity, as well as much better stability and reproducibility than the humidity sensor of ZnSe nanostructure reported before.

Yan Wei [Department of Applied Physics, Chongqing University, 174 Shapingba Street, Chongqing 400044 (China); Hu Chenguo, E-mail: hucg@cqu.edu.cn [Department of Applied Physics, Chongqing University, 174 Shapingba Street, Chongqing 400044 (China); Xi Yi; Wan Buyong; He Xiaoshan; Zhang Michao; Zhang Yan [Department of Applied Physics, Chongqing University, 174 Shapingba Street, Chongqing 400044 (China)

2009-06-03T23:59:59.000Z

180

Luminescence Enhancement in InGaN and ZnO by Water Vapor ...  

Science Conference Proceedings (OSTI)

Dependence of Ag/In Ratio of AgInS2 Crystals Grown by Hot-Press Method ... Analysis of Temperature Characteristics of InGaP/InGaAs/Ge Triple-Junction Solar Cell ... Luminescence Enhancement in InGaN and ZnO by Water Vapor Remote ...

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181

A WHAM-based Kinetics Model for Zn Adsorption and Desorption to  

E-Print Network (OSTI)

A WHAM-based Kinetics Model for Zn Adsorption and Desorption to Soils Z H E N Q I N G S H I model WHAM (Windermere humic aqueous model) to account for the chemical variation during the reaction (e, with the monodentate and bidentate binding sites of humic substancesinWHAM

Sparks, Donald L.

182

Materials and devices research of PPV-ZnO nanowires for heterojunction solar cells  

Science Conference Proceedings (OSTI)

Bulk heterojunction photovoltaic devices, which use the conjugated polymer poly(2-methoxyl-5-(2?-ethylhexyloxy)-1,4- phenylenevinylene) (MEH-PPV) as the electron donor and crystalline ZnO nanowires as the electron acceptor, have been studied in ...

Zhang Xiao-Zhou; Jian Xi-Gao; Zu Li-Wu

2012-01-01T23:59:59.000Z

183

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

SciTech Connect

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.

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

184

Simple and Sensitive Ultraviolet Nanosensors Based on Electrospun ZnO Nanofibers  

SciTech Connect

The current of uniaxially aligned electrospun ZnO nanofibers is modulated reversibly under UV irradiation, with the sensitivity of the UV nanosensors depending on the surface coating of the nanofibers, due to the effect on the photo-generated current.

Zhu, Zhengtao [South Dakota School of Mines and Technology; Zhang, Lifeng [South Dakota School of Mines and Technology; Howe, Jane Y [ORNL; Liao, Liliang [South Dakota School of Mines and Technology; Speidel, Jordan T. [South Dakota School of Mines and Technology; Smith, Steve [South Dakota School of Mines and Technology; Fong, Hao [South Dakota School of Mines and Technology

2009-01-01T23:59:59.000Z

185

Comparative Toxicity of Nanoparticulate CuO and ZnO to Soil Bacterial Communities  

E-Print Network (OSTI)

The increasing industrial application of metal oxide Engineered Nano-Particles (ENPs) is likely to increase their environmental release to soils. While the potential of metal oxide ENPs as environmental toxicants has been shown, lack of suitable control treatments have compromised the power of many previous assessments. We evaluated the ecotoxicity of ENP (nano) forms of Zn and Cu oxides in two different soils by measuring their ability to inhibit bacterial growth. We could show a direct acute toxicity of nano-CuO acting on soil bacteria while the macroparticulate (bulk) form of CuO was not toxic. In comparison, CuSO4 was more toxic than either oxide form. Unlike Cu, all forms of Zn were toxic to soil bacteria, and the bulk-ZnO was more toxic than the nano-ZnO. The ZnSO4 addition was not consistently more toxic than the oxide forms. Consistently, we found a tight link between the dissolved concentration of metal in solution and the inhibition of bacterial growth. The inconsistent toxicological response between soils could be explained by different resulting concentrations of metals in soil solution. Our findings suggested that the principal mechanism of toxicity was dissolution of metal oxides and sulphates into a metal ion form known to be highly toxic to bacteria, and not a direct effect of nano-sized particles acting on bacteria. We propose that integrated efforts toward directly assessing bioavailable metal concentrations are more valuable than spending resources to reassess ecotoxicology of ENPs separately from

Johannes Rousk; Kathrin Ackermann; Simon F. Curling; Davey L. Jones

2012-01-01T23:59:59.000Z

186

Effects of annealing conditions on the photoelectrochemical properties of dye-sensitized solar cells made with ZnO nanoparticles  

SciTech Connect

Dye-sensitized solar cells (DSSCs) were fabricated by using porous ZnO electrodes derived from home-made ZnO nanoparticles. Electrochemical impedance spectra and open-circuit photovoltage decay curves measurements were performed to investigate the photoelectrochemical characteristics of ZnO films annealed at different temperatures. The experimental results indicate that the effects of the bulk traps and the surface states within the ZnO films on the recombination processes of the photoinjected electrons in DSSCs depend on the annealing temperature. The DSSC based on the ZnO electrode annealed at 400 C exhibits an optimal energy conversion efficiency of 3.92% under the illumination of one sun simulated sunlight because the farthest decrease in the effects of both bulk traps and surface states at this film can maintain a lower charge recombination probability. This result indicates that the ZnO film electrode has promising application in the field of DSSCs, and the optimization of porous film fabrication condition is efficient for the improvement of ZnO-based DSSC's performances. (author)

Lu, Lanlan; Li, Renjie; Fan, Ke [College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072 (China); Peng, Tianyou [College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072 (China); State Key Laboratory of Rare Earth Materials Chemistry and Applications, Peking University, Beijing 100871 (China)

2010-05-15T23:59:59.000Z

187

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

Science Conference Proceedings (OSTI)

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.

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

188

Zn-Al layered double hydroxide prepared at different molar ratios: Preparation, characterization, optical and dielectric properties  

Science Conference Proceedings (OSTI)

The co-precipitation method was used to prepare Zn-Al-NO{sub 3}-LDH at different Zn{sup 2+}/Al{sup 3+} molar ratios (2, 3, 4, 5 and 6) and pH value of 7.5. The structure, textural, composition and morphological properties were investigated using powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR) and scanning electron microscope (SEM), respectively. The crystallinity of LDH samples were found to improve as molar ratio decreased which is attributed to the distortion of the hydroxide layers networks of the LDH crystal by the larger difference in ionic radii of Zn{sup 2+} and Al{sup 3+}. The optical band gap energy of LDH samples were evaluated using absorbance data from UV-Vis-NIR Diffuse reflectance spectroscopy. Band gaps were affected by the variation of the Zn{sup 2+}/Al{sup 3+} molar ratio is due to the formation of the low crystalline phases (ZnO and ZnAl{sub 2}O{sub 4}). The water molecules and anionic NO{sub 3}{sup -} in the LDH interlayer were responsible for the generation of the dielectric response. This response can be described by an anomalous low frequency dispersion using the second type of Universal Power Law. The dominance of ZnO dipoles and charge carriers (NO{sub 3}{sup -} ions) in the dielectric relaxation increases with the increasing molar ratio. - Graphical abstract: (a) Schematic diagram of Zn-Al- NO{sub 3}-LDH shows the LDH structure, (b) Kubelka-Munk transformed reflectance spectra and c. The dielectric constant versus frequency of Zn-Al- NO{sub 3}-LDH samples. Highlights: Black-Right-Pointing-Pointer Zn-Al-NO{sub 3}-LDH was prepared at different Zn{sup 2+}/Al{sup 3+} molar ratios (2, 3, 4, 5 and 6). Black-Right-Pointing-Pointer The crystallinity of LDH phase decreased with increase of Zn{sup 2+}/Al{sup 3+} molar ratio. Black-Right-Pointing-Pointer The optical band gaps of LDH samples have been measured. Black-Right-Pointing-Pointer Dielectric response of LDH can be described by anomalous low frequency dispersion.

Ahmed, Abdullah Ahmed Ali [Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Talib, Zainal Abidin, E-mail: zainalat@science.upm.edu.my [Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Zobir bin Hussein, Mohd [Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Advanced Materials and Nanotechnology Laboratory, Institute of Advanced Technology (ITMA), Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Zakaria, Azmi [Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Advanced Materials and Nanotechnology Laboratory, Institute of Advanced Technology (ITMA), Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia)

2012-07-15T23:59:59.000Z

189

A comparative study of ultraviolet photoconductivity relaxation in zinc oxide (ZnO) thin films deposited by different techniques  

Science Conference Proceedings (OSTI)

Photoresponse characteristics of ZnO thin films deposited by three different techniques namely rf diode sputtering, rf magnetron sputtering, and electrophoretic deposition has been investigated in the metal-semiconductor-metal (MSM) configuration. A significant variation in the crystallinity, surface morphology, and photoresponse characteristics of ZnO thin film with change in growth kinetics suggest that the presence of defect centers and their density govern the photodetector relaxation properties. A relatively low density of traps compared to the true quantum yield is found very crucial for the realization of practical ZnO thin film based ultraviolet (UV) photodetector.

Yadav, Harish Kumar; Gupta, Vinay [Department of Physics and Astrophysics, University of Delhi, Delhi 110 007 (India)

2012-05-15T23:59:59.000Z

190

Comparative Study of Zn(O,S) Buffer Layers and CIGS Solar Cells Fabricated by CBD, ALD, and Sputtering: Preprint  

DOE Green Energy (OSTI)

Zn(O,S) thin films were deposited by chemical bath deposition (CBD), atomic layer deposition, and sputtering. Composition of the films and band gap were measured and found to follow the trends described in the literature. CBD Zn(O,S) parameters were optimized and resulted in an 18.5% efficiency cell that did not require post annealing, light soaking, or an undoped ZnO layer. Promising results were obtained with sputtering. A 13% efficiency cell was obtained for a Zn(O,S) emitter layer deposited with 0.5%O2. With further optimization of process parameters and an analysis of the loss mechanisms, it should be possible to increase the efficiency.

Ramanathan, K.; Mann, J.; Glynn, S.; Christensen, S.; Pankow, J.; Li, J.; Scharf, J.; Mansfield, L. M.; Contreras, M. A.; Noufi, R.

2012-06-01T23:59:59.000Z

191

Use of separate ZnTe interface layers to form OHMIC contacts to p-CdTe films  

DOE Patents (OSTI)

A method of 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 tellurim-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.

Gessert, Timothy A. (Conifer, CO)

1999-01-01T23:59:59.000Z

192

Spectroscopic Cathodoluminescence Studies of the ZnTe:Cu Contact Process for CdS/CdTe Solar Cells: Preprint  

DOE Green Energy (OSTI)

This conference paper describes the spectroscopic cathodoluminescence (CL), electron-beam induced current (EBIC), and capacitance-Voltage (C-V) measurements are used to study the formation of CdS/CdTe devices processed using ion-beam milling and a ZnTe:Cu/Ti contact. Results show heating in vacuum at {approx}360 C and ion-beam milling lead to observable changes in the CL emission from the CdCl2-treated CdTe surface. Changes in the CL spectrum are also observed as ZnTe:Cu layer thickness increases. These changes are correlated to published studies of defect levels and shown to be due, possibly, to an n-type region existing between the ZnTe:Cu contact interface and the p-CdTe layers. This n-type region is eliminated once a sufficiently thick ZnTe:Cu layer is produced.

Gessert, T. A.; Romero, M. J.; Johnston, S.; Keyes, B.; Dippo, P.

2002-05-01T23:59:59.000Z

193

Electrical Properties of Point Defects in CdS and ZnS Thin-film PV ...  

Science Conference Proceedings (OSTI)

... Electrical Properties of Point Defects in CdS and ZnS Thin-film PV Buffer ... but whose band gap is too small for complete transparency to solar radiation.

194

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

SciTech Connect

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.

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

195

EGS4 calculations for a Cd-Zn-Te detector to measure synchrotron radiation at PEP-II  

SciTech Connect

Calculations have been performed with the EGS4 Code System for a CdZnTe semiconductor detector to be used in background studies of synchrotron radiation at PEP-II. The simulations take into account K-shell fluorescent-photon production in a CdZnTe mixture, electron-hole pair collection and electronic-noise broadening. The results are compared with measurements made with encapsulated {sup 241}Am, {sup 133}Ba and {sup 109}Cd sources.

Nelson, W.R. [Stanford Univ., CA (US). Stanford Linear Accelerator Center; Borak, T.; Malchow, R.; Toki, W. [Colorado State Univ., Fort Collins, CO (US); Kadyk, J. [Lawrence Berkeley National Lab., CA (US)

1997-08-20T23:59:59.000Z

196

EGS4 CALCULATIONS FOR A Cd-Zn-Te DETECTOR TO? y MEASURE SYNCHROTRON RADIATION AT PEP-II  

E-Print Network (OSTI)

Calculations have been performed with the EGS4 Code System for a CdZnTe semiconductor detector to be used in background studies of synchrotron radiation at PEP-II. The simulations take into account K-shell uorescent-photon production in a CdZnTe mixture, electron-hole pair collection and electronic-noise broadening. The results are compared with measurements made with encapsulated 241 Am, 133 Ba and 109 Cd sources.

W. R. Nelson; T. Borak; R. Malchow; W. Toki; J. Kadyk

1997-01-01T23:59:59.000Z

197

Improved electrical transport properties in p-type ZnO film by Rapid Dark thermal annealing process  

SciTech Connect

A rapid dark thermal annealing process at 800 deg. C of radio frequency sputtered P doped ZnO thin films have resulted in improved electrical transport properties with hole concentration of 1 x 1018 cm-3, mobility 4.37 cm2/Vs and resistivity 1.4 {Omega}-cm. X-ray photoelectron spectroscopy shows the presence of inactivated P in as-grown ZnO films.

Ghosh, Tushar; Basak, Durga [Department of Solid State Physics, Indian Association for the Cultivation of science, Jadavpur, Kolkata-700032 (India)

2012-06-05T23:59:59.000Z

198

Experimental study of double-{beta} decay modes using a CdZnTe detector array  

SciTech Connect

An array of sixteen 1 cm{sup 3} CdZnTe semiconductor detectors was operated at the Gran Sasso Underground Laboratory (LNGS) to further investigate the feasibility of double-{beta} decay searches with such devices. As one of the double-{beta} decay experiments with the highest granularity the 4x4 array accumulated an overall exposure of 18 kg days. The setup and performance of the array is described. Half-life limits for various double-{beta} decay modes of Cd, Zn, and Te isotopes are obtained. No signal has been found, but several limits beyond 10{sup 20} years have been performed. They are an order of magnitude better than those obtained with this technology before and comparable to most other experimental approaches for the isotopes under investigation. An improved limit for the {beta}{sup +}/EC decay of {sup 120}Te is given.

Dawson, J. V. [Laboratoire Astroparticule et Cosmologie, 10 rue Alice Domon et Leonie Duquet, F-75205 Paris (France); Goessling, C.; Koettig, T.; Muenstermann, D.; Rajek, S.; Schulz, O. [Lehrstuhl fuer Experimentelle Physik IV, Technische Universitaet Dortmund, Otto-Hahn Str. 4, D-44227 Dortmund (Germany); Janutta, B.; Zuber, K. [Institut fuer Kern- und Teilchenphysik, Technische Universitaet Dresden, Zellescher Weg 19, D-01069 Dresden (Germany); Junker, M. [Laboratori Nazionali del Gran Sasso, Assergi (Italy); Reeve, C. [University of Sussex, Falmer, Brighton BN1 9QH (United Kingdom); Wilson, J. R. [University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom)

2009-08-15T23:59:59.000Z

199

Photoluminescence in disordered Zn{sub 2}TiO{sub 4}  

SciTech Connect

In this work, the polymeric precursor method was used to obtain disordered Zn{sub 2}TiO{sub 4} powders, either undoped or doped with Sn{sup 4+}, Cr{sup 3+} and V{sup 5+}, to be applied as photoluminescent material. The characterization was undertaken by means of thermal analysis (TG and DTA), X-ray diffraction (XRD), infrared spectroscopy (IR) and photoluminescence (PL). Previous works stated that titanate octahedra containing a short Ti-O distance show efficient luminescence at room temperature if these octahedra are isolated from each other. In the present work, the phenomenon was observed in condensed octahedra, sharing edges. The room temperature PL noticed in undoped Zn{sub 2}TiO{sub 4} had its intensity increased by the dopant addition-the increase was of about 300% for V{sup 5+} doping, 400% for Cr{sup 3+} and 800% for Sn{sup 4+}.

Chaves, Alexsandra C. [LTM, Departamento de Quimica, CCEN, Universidade Federal da Paraiba, 58059-900, Joao Pessoa, PB (Brazil); Lima, Severino J.G. [LSR, Departamento de Tecnologia Mecanica, CT, Universidade Federal da Paraiba, 58059-900, Joao Pessoa, PB (Brazil); Araujo, Regiane C.M.U. [LTM, Departamento de Quimica, CCEN, Universidade Federal da Paraiba, 58059-900, Joao Pessoa, PB (Brazil); Maurera, Maria Aldeiza M.A. [LTM, Departamento de Quimica, CCEN, Universidade Federal da Paraiba, 58059-900, Joao Pessoa, PB (Brazil); Longo, Elson [CMDMC, Instituto de Quimica de Araraquara, UNESP, 14800-900, Araraquara, SP (Brazil); Pizani, Paulo S. [Departamento de Fisica, Universidade Federal de Sao Carlos, Caixa Posta 676, 13565-905, Sao Carlos, SP (Brazil); Simoes, Luiz G.P. [CMDMC, Instituto de Quimica de Araraquara, UNESP, 14800-900, Araraquara, SP (Brazil); Soledade, Luiz E.B. [LTM, Departamento de Quimica, CCEN, Universidade Federal da Paraiba, 58059-900, Joao Pessoa, PB (Brazil); Souza, Antonio G. [LTM, Departamento de Quimica, CCEN, Universidade Federal da Paraiba, 58059-900, Joao Pessoa, PB (Brazil); Santos, Ieda Maria Garcia dos [LTM, Departamento de Quimica, CCEN, Universidade Federal da Paraiba, 58059-900, Joao Pessoa, PB (Brazil)]. E-mail: ieda@quimica.ufpb.br

2006-04-15T23:59:59.000Z

200

p-Type ZnO Thin Films Grown by MOCVD  

DOE Green Energy (OSTI)

ZnO has demonstrated a possibility to be doped as a p-type by using nitrogen and other group-V elements. A high nitrogen doping concentration by metalorganic chemical vapor deposition (MOCVD) with nitric oxide (NO) gas has been achieved. However, the processing window for obtaining the p-type ZnO:N film is very narrow, and the hole concentration is typically low. Possible compensation and passivation effects have been studied. Hydrogen and carbon elements are detected by secondary-ion mass spectroscopy (SIMS). Considering the other experimental and modeling results, we believe that the impurities inadvertently incorporated with the zinc precursor could be compensating or passivating the nitrogen acceptor and result in the low hole concentration.

Li, X.; Asher, S. E.; Keyes, B. M.; Moutinho, H. R.; Luther, J.; Coutts, T. J.

2005-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "zn zurn ot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

www.elsevier.com/locate/jssc Photoluminescence in disordered Zn 2TiO 4  

E-Print Network (OSTI)

In this work, the polymeric precursor method was used to obtain disordered Zn2TiO4 powders, either undoped or doped with Sn 4+, Cr 3+ and V 5+, to be applied as photoluminescent material. The characterization was undertaken by means of thermal analysis (TG and DTA), X-ray diffraction (XRD), infrared spectroscopy (IR) and photoluminescence (PL). Previous works stated that titanate octahedra containing a short Ti–O distance show efficient luminescence at room temperature if these octahedra are isolated from each other. In the present work, the phenomenon was observed in condensed octahedra, sharing edges. The room temperature PL noticed in undoped Zn2TiO4 had its intensity increased by the dopant addition—the increase was of about 300 % for V 5+ doping, 400 % for Cr 3+ and 800% for Sn 4+.

Ra C. Chaves A; Severino J. G. Lima B; Maria Aldeiza; M. A. Maurera A; Elson Longo C; Paulo S. Pizani D; Luiz G. P. Simo˜es C; Luiz E. B. Soledade A; Antonio G. Souza A; Ieda Maria; Garcia Santos

2005-01-01T23:59:59.000Z

202

Band offsets in ZrO{sub 2}/InGaZnO{sub 4} heterojunction  

SciTech Connect

X-ray photoelectron spectroscopy was used to measure the energy discontinuity in the valence band ( White-Up-Pointing-Triangle E{sub V}) of amorphous InGaZnO{sub 4} (a-IGZO)/ZrO{sub 2} heterostructure deposited by DC and RF sputtering at room temperature, respectively. A value of White-Up-Pointing-Triangle E{sub V}= 0 eV was obtained by using the Ga and Zn 2p{sup 3} and In 3d{sup 3} energy levels as references. Given the experimental band gap of 3.1 eV and 5.8 eV for the a-IGZO and ZrO{sub 2}, respectively, this would indicate a conduction band offset of 2.7 eV in the system.

Yao Jianke [School of Computer and Information Engineering, Shenzhen Graduate School, Peking University, Shenzhen 518055 (China); Zhang Shengdong [School of Computer and Information Engineering, Shenzhen Graduate School, Peking University, Shenzhen 518055 (China); Institute of Microelectronics, Peking University, Beijing 100871 (China); Gong Li [Instrumental Analysis and Research Center, Sun Yat-Sen University, Guangzhou 510275 (China)

2012-08-27T23:59:59.000Z

203

Removal of Zn or Cd and cyanide from cyanide electroplating wastes  

DOE Patents (OSTI)

A method is described for the efficient stripping of stable complexes of a selected quaternary amine and a cyanide of Zn or Cd. An alkali metal hydroxide solution such as NaOH or KOH will quantitatively strip a pregnant extract of the quaternary ammonium complex of its metal and cyanide content and regenerate a quaternary ammonium hydroxide salt which can be used for extracting further metal cyanide values.

Moore, Fletcher L. (Knoxville, TN)

1977-05-31T23:59:59.000Z

204

Quantum-confinement versus strain effects in the Zn(Cd)S(Se) family of superlattices  

Science Conference Proceedings (OSTI)

We have investigated the quantum-confinement (QC) and strain effects on the band structures of the Zn(Cd)S(Se) family of binary-compound superlattices (SLs); particularly those with common anions and with common cations. All the studied cases of SLs ... Keywords: 71.20.Nr, 71.55.Gs, 73.21.Fg, 73.61.Ga, II-VI semiconductors, Semiconductor compounds, Superlattices

Ihab M. Obaidat; Nacir Tit

2009-03-01T23:59:59.000Z

205

Photo-degradation of methylene blue using Ta-doped ZnO nanoparticle  

SciTech Connect

A photocatalyst of Ta-doped ZnO was prepared by a modified Pechini-type method. The structural, morphological properties and photocatalytic activity of 1 mol % Ta-doped ZnO samples annealed at different temperatures were characterized. The photo-oxidation of methylene blue under the visible-light irradiation followed the pseudo-first-order kinetics according to the Langmuir-Hinshelwood model. It is found that the photocatalysis of 1% Ta-doped ZnO annealed at 700 {sup o}C showed excellent performance of the photodegradation of methylene blue, which was attributed to a competitive trade-off among the crystallinity, surface hydroxyl groups, and specific surface area. The processing parameter such as the pH value also played an important role in tuning the photocatalytic activity. The maximum photodecomposed rate was achieved at pH=8, and an novel model about the absorption of methylene blue on the surface of the catalysts was proposed. - Graphical abstract: This model describes the adsorption between the amphoteric behavior of the metal oxide and the cationic dye methylene blue (MB) on the surface of the catalyst at the acidic and alkaline condition.

Kong Jizhou [National Laboratory of Solid State Microstructures, Materials Science and Engineering Department, Nanjing University, Nanjing 210093 (China); Li Aidong, E-mail: adli@nju.edu.c [National Laboratory of Solid State Microstructures, Materials Science and Engineering Department, Nanjing University, Nanjing 210093 (China); Li Xiangyu; Zhai Haifa; Zhang Wenqi; Gong Youpin; Li Hui; Wu Di [National Laboratory of Solid State Microstructures, Materials Science and Engineering Department, Nanjing University, Nanjing 210093 (China)

2010-06-15T23:59:59.000Z

206

Thermochemical cycles for energy storage: Thermal decomposition of ZnCO sub 4 systems  

DOE Green Energy (OSTI)

The overall objective of our research has been to develop thermochemical cycles that can be used for energy storage. A specific cycle involving ammonium hydrogen sulfate (NH{sub 4}HSO{sub 4}) has been proposed. Each reaction in the proposed cycle has been examined experimentally. Emphasis has been placed on the basic chemistry of these reactions. In the concluding phase of this research, reported herein, we have shown that when NH{sub 4}HSO{sub 4} is mixed with ZnO and decomposed, the resulting products can be released stepwise (H{sub 2}A{sub (g)} at {approximately}163{degrees}C, NH{sub 3(g)} at 365--418{degrees}C, and a mixture of SO{sub 2(g)} and SO{sub 3(g)} at {approximately}900{degrees}C) and separated by controlling the reaction temperature. Side reactions do not appear to be significant and the respective yields are high as would be required for the successful use of this energy storage reaction in the proposed cycle. Thermodynamic, kinetic, and other reaction parameters have been measured for the various steps of the reaction. Finally we have completed a detailed investigation of one particular reaction: the thermal decomposition of zinc sulfate (ZnSO{sub 4}). We have demonstrated that this reaction can be accelerated and the temperature required reduced by the addition of excess ZnO, V{sub 2}A{sub 5} and possibly other metal oxides.

Wentworth, W.E. (Houston Univ., TX (United States))

1992-04-01T23:59:59.000Z

207

Factors Affecting the Hydrogen Environment Assisted Cracking Resistance of an AL-Zn-Mg-(Cu) Alloy  

DOE Green Energy (OSTI)

Precipitation hardenable Al-Zn-Mg alloys are susceptible to hydrogen environment assisted cracking (HEAC) when exposed to aqueous environments. In Al-Zn-Mg-Cu alloys, overaged tempers are used to increase HEAC resistance at the expense of strength but overaging has little benefit in low copper alloys. However, the mechanism or mechanisms by which overaging imparts HEAC resistance is poorly understood. The present research investigated hydrogen uptake, diffusion, and crack growth rate in 90% relative humidity (RH) air for both a commercial copper bearing Al-Zn-Mg-Cu alloy (AA 7050) and a low copper variant of this alloy in order to better understand the factors which affect HEAC resistance. Experimental methods used to evaluate hydrogen concentrations local to a surface and near a crack tip include nuclear reaction analysis (NRA), focused ion beam, secondary ion mass spectroscopy (FIB/SIMS) and thermal desorption spectroscopy (TDS). Results show that overaging the copper bearing alloys both inhibits hydrogen ingress from oxide covered surfaces and decreases the apparent hydrogen diffusion rates in the metal.

G.A. Young; J.R. Scully

2002-04-09T23:59:59.000Z

208

Modulated structure of [beta]-brass CuZn compressed to 90 GPa  

Science Conference Proceedings (OSTI)

Cu-Zn is a classic example of an alloy system displaying a sequence of phases along an alloy composition, called Hume-Rothery phases. The crystal structure of these phases is determined by valence electron concentration (that is the average number of valence electrons per atom), and the lowering of the electronic energy is considered the key factor for the structure stabilization. Using powder x-ray diffraction, we study the {beta}-phase of an equiatomic CuZn alloy in its body-centered cubic (bcc) phase in the pressure range up to 90 GPa and find a transformation to a modulated trigonal structure at around 40 GPa. We analyze the structural distortion of bcc CuZn by looking at the configuration of the Brillouin zone of the bcc and the trigonal structures and their interaction with the Fermi surface. We demonstrate that the stabilization of the complex high-pressure structure can be explained with the Hume-Rothery effect.

Degtyareva, Olga; Degtyareva, Valentina F. (Edinburgh); (CIW)

2010-05-21T23:59:59.000Z

209

Stability of hume rothery phases in Cu?Zn alloys at pressures up to 50 GPa  

Science Conference Proceedings (OSTI)

The crystal structure of the {gamma}-brass phase Cu{sub 5}Zn{sub 8} is confirmed with single-crystal X-ray diffraction and a charge-coupled device (CCD) detector to be cubic with 52 atoms in the unit cell, space group I{bar 4}3m, and the refined atomic positions are in good agreement with previously reported data. The structural behavior of {alpha}-(fcc), {beta}-brass (cI52) phases of the Cu-Zn alloy system has been studied under pressure using diamond anvil cells and powder X-ray diffraction with synchrotron radiation. The appearance of additional peaks in the diffraction patterns of {alpha}- and {beta}-phases indicates the beginning of transitions to new phases at 17 and 37 GPa, respectively. The complex cubic {gamma}-brass phase (52 atoms in the unit cell, space group I{bar 4}3m) is observed to be stable up to at least 50 GPa. The bulk modulus K 0 was determined as 140(4) GPa for {alpha}-, 139(5) for {beta}-, and 121(2) for {gamma}-phase assuming K 0 = 4. The structural stability of brass phases of the Cu-Zn system under pressure is discussed in terms of the Hume-Rothery mechanism.

Degtyareva, V.F.; Sakharov, M.K.; Novokhatskaya, N.I.; Degtyareva, O.; Dera, P.; Mao, H.-K.; Hemley, R.J. (Edinburgh); (Russ. Acad. Sci.); (CIW)

2008-06-17T23:59:59.000Z

210

Ultrafast intramolecular relaxation dynamics of Mg- and Zn-bacteriochlorophyll a  

SciTech Connect

Ultrafast excited-state dynamics of the photosynthetic pigment (Mg-)bacteriochlorophyll a and its Zn-substituted form were investigated by steady-state absorption/fluorescence and femtosecond pump-probe spectroscopic measurements. The obtained steady-state absorption and fluorescence spectra of bacteriochlorophyll a in solution showed that the central metal compound significantly affects the energy of the Q{sub x} state, but has almost no effect on the Q{sub y} state. Photo-induced absorption spectra were recorded upon excitation of Mg- and Zn-bacteriochlorophyll a into either their Q{sub x} or Q{sub y} state. By comparing the kinetic traces of transient absorption, ground-state beaching, and stimulated emission after excitation to the Q{sub x} or Q{sub y} state, we showed that the Q{sub x} state was substantially incorporated in the ultrafast excited-state dynamics of bacteriochlorophyll a. Based on these observations, the lifetime of the Q{sub x} state was determined to be 50 and 70 fs for Mg- and Zn-bacteriochlorophyll a, respectively, indicating that the lifetime was influenced by the central metal atom due to the change of the energy gap between the Q{sub x} and Q{sub y} states.

Kosumi, Daisuke [Osaka City University Advanced Research Institute for Natural Science and Technology, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan); CREST/JST, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Nakagawa, Katsunori; Sakai, Shunsuke [Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Nagaoka, Yuya; Maruta, Satoshi; Sugisaki, Mitsuru [CREST/JST, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Department of Physics, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan); Dewa, Takehisa [Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); PRESTO/JST, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Nango, Mamoru [The Osaka City University Advanced Research Institute for Natural Science and Technology, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan); CREST/JST, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Hashimoto, Hideki [The Osaka City University Advanced Research Institute for Natural Science and Technology, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan); CREST/JST, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Department of Physics, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan)

2013-07-21T23:59:59.000Z

211

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

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.

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

212

Defect energetics and electronic structures of As-doped p-type ZnO crystals: A first-principles study  

E-Print Network (OSTI)

First-principles calculations based on density functional theory have been carried out to understand the mechanism of fabricating As-doped p-type ZnO semiconductors. It has been confirmed that AsZn-2VZn complex is the most plausible acceptor among several candidates for p-type doping by computing the formation and ionization energies. The electronic band structures and atomic-projected density of states of AsZn-2VZn defect complex-contained ZnO bulks have been computed. The acceptor level in AsZn-2VZn band structure has found to be 0.12 eV, which is in good agreement with the experimental ionization energy (0.12 ~ 0.18 eV). The hybridization among O 2p, Zn 3d and As 4s states has been observed around the valence band maximum.

Yu, Chol-Jun; Ri, Son-Guk; Kim, Myong-Il; Im, Song-Jin

2013-01-01T23:59:59.000Z

213

Enhanced T-lymphocyte blastogenic response to tuberculin (PPD) in children of northeast (NE) Thailand supplemented with vitamin A (VA) and zinc (Zn)  

SciTech Connect

Beneficial effects of Va and/or Zn supplementation of children in NE Thailand are described in a companion abstract. In the same study, blastogenic response (BR) of T-lymphocytes to concanavalin-A (ConA) and PPD were assayed in cultures containing mononuclear cells (MNC) or whole blood (WB). Methods were previously described. Children were previously vaccinated with BCG. BR to ConA of MNC or WB from children supplemented with VA, Zn, VA + Zn or placebo were similar. BR to PPD of MNC was higher in children receiving VA + Zn than placebo, but not in children supplemented with VA or Zn alone. Data indicate that children with suboptimal VA and Zn nutriture supplemented with < 2 times RDA of these nutrients showed enhanced cellular immunity to PPD. This observation is relevant to BCG immunization program and thus may benefit public health.

Kramer, T.R.; Udomkesmalee, E.; Dhanamitta, S.; Sirisinha, S.; Charoenkiatkul, S.; Tantipopipat, S.; Banjong, O.; Rojroongwasinkul, N.; Smith, J.C. Jr. (Dept. of Agriculture, Beltsville, MD (United States) Mahidol Univ., Nakhon Pathom (Thailand))

1991-03-15T23:59:59.000Z

214

Synthesis of Methanol and Dimethyl Ether from Syngas over Pd/ZnO/Al2O3 Catalysts  

SciTech Connect

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 250°C to 380°C. High temperatures (e.g. 380°C) 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 220-280°C, suffers from a rapid deactivation when the reaction is conducted at high temperature (>320°C). On the contrary, a Pd/ZnO/Al2O3 catalyst was found to be highly stable for methanol and DME synthesis at 380°C. The Pd/ZnO/Al2O3 catalyst was thus further investigated for methanol and DME synthesis at P=34-69 bars, T= 250-380°C, 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 GHSV’s 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 Pdº 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.

Lebarbier, Vanessa MC; Dagle, Robert A.; Kovarik, Libor; Lizarazo Adarme, Jair A.; King, David L.; Palo, Daniel R.

2012-10-01T23:59:59.000Z

215

Investigation of the Effect of I-ZnO Window Layer on the Device Performance of the Cd-Free CIGS Based Solar Cells (Poster)  

DOE Green Energy (OSTI)

This research work focuses on preparing Cd-free CIGS based solar cells with intrinsic high resistivity ZnO (I-ZnO) films deposited by metal-organic chemical vapor deposition (MOCVD) technique at different deposition substrate temperature and I-ZnO film thickness, and the effect of the prior treatment of CIGS films by ammonium hydroxide (NH4OH) diluted solution on the device performance.

Hasoon, F. S.; al-Thani, H. A.; Li, X.; Kanevce, A.; Perkins, C.; Asher, S.

2008-05-01T23:59:59.000Z

216

Investigation of the Effect of I-ZnO Window Layer on the Device Performance of the Cd-Free CIGS Based Solar Cells: Preprint  

DOE Green Energy (OSTI)

This paper focuses on preparing Cd-free, CIGS-based solar cells with intrinsic high resistivity ZnO (I-ZnO) films deposited by metal-organic chemical vapor deposition (MOCVD) technique at different deposition substrate temperature and I-ZnO film thickness, and the effect of the prior treatment of CIGS films by ammonium hydroxide (NH4OH) diluted solution on the device performance.

Hasoon, F. S.; Al-Thani, H. A.; Li, X.; Kanevce, A.; Perkins, C.; Asher, S.

2008-05-01T23:59:59.000Z

217

SnO{sub 2}/ZnO composite structure for the lithium-ion battery electrode  

SciTech Connect

In this article, SnO{sub 2}/ZnO composite structures have been synthesized by two steps hydrothermal method and investigated their lithium storage capacity as compared with pure ZnO. It has been found that these composite structures combining the large specific surface area, stability and catalytic activity of SnO{sub 2} micro-crystals, demonstrate the higher initial discharge capacity of 1540 mA h g{sup -1} with a Coulombic efficiency of 68% at a rate of 120 mA h g{sup -1} between 0.02 and 2 V and found much better than that of any previously reported ZnO based composite anodes. In addition, a significantly enhanced cycling performance, i.e., a reversible capacity of 497 mA h g{sup -1} is retained after 40 cycles. The improved lithium storage capacity and cycle life is attributed to the addition of SnO{sub 2} structure, which act as good electronic conductors and better accommodation of the large volume change during lithiation/delithiation process. - Graphical abstract: SnO{sub 2}/ZnO composite structures demonstrate the improved lithium storage capacity and cycle life as compared with pure ZnO nanostructure. Highlights: Black-Right-Pointing-Pointer Synthesis of SnO{sub 2}/ZnO composite structures by two steps hydrothermal approach. Black-Right-Pointing-Pointer Investigation of lithium storage capacity. Black-Right-Pointing-Pointer Excellent lithium storage capacity and cycle life of SnO{sub 2}/ZnO composite structures.

Ahmad, Mashkoor, E-mail: mashkoorahmad2003@yahoo.com [Beijing National Center for Electron Microscopy, The State Key Laboratory of New Ceramics and Fine Processing, Laboratory of Advanced Material, China Iron and Steel Research Institute Group, Department of Material Science and Engineering, Tsinghua University, Beijing 100084 (China) [Beijing National Center for Electron Microscopy, The State Key Laboratory of New Ceramics and Fine Processing, Laboratory of Advanced Material, China Iron and Steel Research Institute Group, Department of Material Science and Engineering, Tsinghua University, Beijing 100084 (China); Nanomaterial Research Group, Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan); Yingying, Shi [Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)] [Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Sun, Hongyu [Beijing National Center for Electron Microscopy, The State Key Laboratory of New Ceramics and Fine Processing, Laboratory of Advanced Material, China Iron and Steel Research Institute Group, Department of Material Science and Engineering, Tsinghua University, Beijing 100084 (China)] [Beijing National Center for Electron Microscopy, The State Key Laboratory of New Ceramics and Fine Processing, Laboratory of Advanced Material, China Iron and Steel Research Institute Group, Department of Material Science and Engineering, Tsinghua University, Beijing 100084 (China); Shen, Wanci [Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)] [Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Zhu, Jing, E-mail: jzhu@mail.tsinghua.edu.cn [Beijing National Center for Electron Microscopy, The State Key Laboratory of New Ceramics and Fine Processing, Laboratory of Advanced Material, China Iron and Steel Research Institute Group, Department of Material Science and Engineering, Tsinghua University, Beijing 100084 (China)] [Beijing National Center for Electron Microscopy, The State Key Laboratory of New Ceramics and Fine Processing, Laboratory of Advanced Material, China Iron and Steel Research Institute Group, Department of Material Science and Engineering, Tsinghua University, Beijing 100084 (China)

2012-12-15T23:59:59.000Z

218

Band offsets for mismatched interfaces: The special case of ZnO on CdTe (001)  

SciTech Connect

High-quality planar interfaces between ZnO and CdTe would be useful in optoelectronic applications, but appear difficult to achieve given the rather different crystal structures (CdTe is zinc blende with cubic lattice constant a = 6.482 Å, ZnO is hexagonal wurtzite with a = 3.253 Å and c = 5.213 Å.) However, ZnO has been reported to occur in some epitaxially stabilized films in the zinc blende structure with an fcc primitive lattice constant close to the hexagonal a value. Observing that this value equals half of the CdTe cubic lattice constant to within 1%, we propose that (001)-oriented cubic ZnO films could be grown epitaxially on a CdTe (001) surface in an R45° ?2??2 configuration. Many terminations and alignments (in-plane fractional translations) are possible, and we describe density-functional total-energy electronic-structure calculations on several configurations to identify the most likely form of the interface, and to predict valence-band offsets between CdTe and ZnO in each case. Growth of ZnO on Te-terminated CdTe (001) is predicted to produce small or even negative (CdTe below ZnO) valence band offsets, resulting in a Type I band alignment. Growth on Cd-terminated CdTe is predicted to produce large positive offsets for a type II alignment as needed, for example, in solar cells. We also describe recent experiments that corroborate some of these predictions.

Jaffe, John E.; Kaspar, Tiffany C.; Droubay, Timothy; Varga, Tamas

2013-08-02T23:59:59.000Z

219

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

E-Print Network (OSTI)

Cu X S/(Cd,Zn)S PHOTOVOLTAIC SOLAR ENERGY CONVERTERS 3/77 -of Research on Photovoltaic Solar Energy Converters CuxSI(Cd

Chin, B.L.

2013-01-01T23:59:59.000Z

220

Element specific measurements of the structural properties and magnetism of CoxZn1-xO  

SciTech Connect

Sparked by theoretical predictions for p-type ZnO, CoxZn1-xO (Co:ZnO) is one of the most favoured materials within the search for a doped semiconductor with ferromagnetic properties at room temperature—an essential prerequisite for spintronics. Despite early experimental reports of high temperature ferromagnetism, mainly based on measurements performed with superconducting quantum interference device (SQUID),the experimental findings become more and more controversial. Recent reports claim a paramagnetic behavior of the Co-sublattice or suggest extrinsic origins of the observed ferromagnetism. Here we present studies on Co:ZnO samples with nominally 10% cobalt content grown either by magnetron sputtering or pulsed laser deposition (PLD). Since we have recently shown that the dopant behaves purely paramagnetic in case of high structural perfection achieved by PLD growth [6], we focus in this work on structural and magnetic differences of the latter to films produced by reactive magnetron sputtering (RMS). Some reports consider native oxygen vacancies of ZnO as a possible origin of ferromagnetic-like behaviour, therefore we study the magnetic properties of samples which were intentionally grown under a reduced oxygen partial pressure.

Kammermeier, T.; Ney, V.; Ye, S.; Ollefs, K.; Kaspar, Tiffany C.; Chambers, Scott A.; Wilhelm, F.; Rogalev, A.; Ney, A.

2009-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "zn zurn ot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Schottky barrier height behavior of Pt-Ru alloy contacts on single-crystal n-ZnO  

SciTech Connect

We investigated the Schottky barrier height (SBH) behavior of binary alloy Schottky contacts on n-type zinc oxide (n-ZnO) single crystals. Pt-Ru alloy electrodes were deposited on the Zn-polar and O-polar faces of ZnO substrates by combinatorial ion-beam deposition under identical conditions. The crystal structures of the Pt-Ru alloy film changed from the Pt phase (cubic structure) to the Ru phase (hexagonal structure) in the Pt-Ru alloy phase diagram with decreasing Pt content. The SBH, determined from current-voltage measurements, decreased with decreasing Pt content, indicating that the SBH behavior also followed the Pt-Ru alloy phase diagram. The alloy electrodes on the Zn-polar face showed better Schottky properties than those on the O-polar face. Hard x-ray photoelectron spectroscopy revealed a difference in the interface oxidization of the Pt-Ru alloy: the interface of the O-polar face and Pt-Ru mixed phase with poor crystallinity had a more oxidized layer than that of the Zn-polar face. As a result of this oxidization, the O-polar face, Pt-Ru mixed, and Ru phases showed poor Schottky properties.

Nagata, T.; Haemori, M.; Hayakawa, R.; Yoshitake, M.; Chikyow, T. [Advanced Electronic Materials Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Volk, J. [Research Institute for Technical Physics and Materials Science, H-1121 Budapest, Konkoly Thege Miklos ut 29-33 (Hungary); Yamashita, Y. [Advanced Electronic Materials Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); NIMS Beamline Station at SPring-8, National Institute for Materials Science, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Yoshikawa, H.; Ueda, S.; Kobayashi, K. [NIMS Beamline Station at SPring-8, National Institute for Materials Science, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan)

2010-05-15T23:59:59.000Z

222

Computer simulation of the energy gap in ZnO- and TiO{sub 2}-based semiconductor photocatalysts  

SciTech Connect

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).

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

223

Investigation of polycrystalline thin film CuInSe{sub 2} solar cells based on ZnSe windows. Annual subcontract report, 15 February, 1993--14 February, 1994  

DOE Green Energy (OSTI)

This report concerns studies of CIS solar cells based on ZnSe window layers. ZnSe/CIS devices are fabricated by growing ZnSe films by MOCVD onto Siemens CIS and graded absorber substrates. ZnSe films are grown by reacting H{sub 2}Se with a zinc adduct. ZnSe/CIS heterojunctions have been studied by depositing transparent aluminum contacts onto ZnSe. These studies indicate that ZnSe/CIS solar cells can be fabricated with an efficiency greater than 14%. Open circuit voltages are typically larger than 500 mV and the optimum range of ZnSe film thickness for maximum efficiency is between 100 {angstrom} and 250 {angstrom}. Photocurrents are significantly reduced as the film thickness exceeds 250 {angstrom}. Photoluminescence spectroscopy has been utilized to characterize the physical nature of CIS substrate surfaces, and ZnSe-CIS interfaces. These studies indicate that a segregated phase(s) exists at the surface of as received Siemens substrates. Additionally, it is determined that the segregated phase(s) still exist after the ZnSe growth process. To date, sputtered ZnO top contact layers have caused degradation of the photovoltaic properties of the ZnSe/CIS structure. Investigations of the effects of MOCVD grown ZnO upon ZnSe/CIS structures will soon be initiated. To establish the feasibility of ZnSe as a window layer, cells have been fabricated by incorporating a protective layer of CdS between the ZnSe and ZnO. A total area efficiency of 11% was obtained with such a structure.

Olsen, L.C. [Washington State Univ., Richland, WA (United States)

1995-03-01T23:59:59.000Z

224

Comparative Study of the Defect Point Physics and Luminescence of the Kesterites Cu2ZnSnS4 and Cu2ZnSnSe4 and Chalcopyrite Cu(In,Ga)Se2: Preprint  

DOE Green Energy (OSTI)

In this contribution, we present a comparative study of the luminescence of the kesterites Cu2ZnSnS4 (CZTS) and Cu2ZnSnSe4 (CZTSe) and their related chalcopyrite Cu(In,Ga)Se2 (CIGSe). Luminescence spectroscopy suggests that the electronic properties of Zn-rich, Cu-poor kesterites (both CZTS and CZTSe) and Cu-poor CIGSe are dictated by fluctuations of the electrostatic and chemical potentials. The large redshift in the luminescence of grain boundaries in CIGSe, associated with the formation of a neutral barrier is clearly observed in CZTSe, and, to some extent, in CZTS. Kesterites can therefore replicate the fundamental electronic properties of CIGSe.

Romero, M. J.; Repins, I.; Teeter, G.; Contreras, M.; Al-Jassim, M.; Noufi, R.

2012-08-01T23:59:59.000Z

225

Hard x-ray response of a CdZnTe ring-drift detector  

Science Conference Proceedings (OSTI)

We present the results of an experimental study of a special type of CdZnTedetector of hard x and ? rays—a ring-drift detector. The device consists of a double ring electrode structure surrounding a central point anode with a guard plane surrounding the outer anode ring. The detector can be operated in two distinctively different modes of charge collection—pseudohemispherical and pseudodrift. We study the detector response profiles obtained by scanning the focused x-ray beam over the whole detector area

A. Owens; R. den Hartog; F. Quarati; V. Gostilo; V. Kondratjev; A. Loupilov; A. G. Kozorezov; J. K. Wigmore; A. Webb; E. Welter

2007-01-01T23:59:59.000Z

226

Effect of Sub-Bandgap Illumination on the Internal Electric Field of CdZnTe  

SciTech Connect

Post-growth manipulation of the internal electric field in CdZnTe crystals using sub-bandgap illumination is measured as a function of temperature through infrared (IR) transmission measurements. Using near sub-bandgap IR illumination, both the optical de-trapping of charge carriers and the reduction in carrier recombination increased the mobility lifetime in the crystal. The increased carrier transport is a direct result of decreased hole and electron trapping in addition to other underlying mechanisms. Concentration of the electric field near the cathode is also observed. We measured the electric field distribution with sub-bandgap illumination as a function of temperature via the Pockels effect.

Washington, A.

2011-09-16T23:59:59.000Z

227

Characterization of Heterogeneities in Detector-Grade CdZnTe Crystals  

Science Conference Proceedings (OSTI)

Synthetic Cd{sub 1-x}ZnxTe or 'CZT' crystals are highly suitable for g-spectrometers operating at room temperature. Secondary phases (SP) within CZT, presumed to be Te metal, have detrimental impacts on the charge collection efficiency of fabricated device. Using analytical techniques rather than arbitrary theoretical definitions, we identify two SP morphologies: (i) many void, 20-{mu}m 'negative' crystals with 65-nm nanoparticle residues of Si, Cd, Zn, and Te and (ii) 20-{mu}m hexagonal-shaped bodies, which are composites of metallic Te layers with cores of amorphous and polycrystalline CZT material that surround the voids.

Duff, M.; Hunter, D; Burger, A; Groza, M; Buliga, V; Bradley, J; Graham, G; Dai, Z; Lanzirotti, A; et. al.

2009-01-01T23:59:59.000Z

228

Light-Induced Tellurium Enrichment on CdZnTe Crystal Surfaces Detected by Raman Spectroscopy  

Science Conference Proceedings (OSTI)

CdZnTe (CZT) crystals can be grown under controlled conditions to produce high-quality crystals to be used as room-temperature radiation detectors. Even the best crystal growth methods result in defects, such as tellurium secondary phases, that affect the crystal's performance. In this study, CZT crystals were analyzed by micro-Raman spectroscopy. The growth of Te rich areas on the surface was induced by low-power lasers. The growth was observed versus time with low-power Raman scattering and was observed immediately under higher-power conditions. The detector response was also measured after induced Te enrichment.

Hawkins, Samantha A.; Villa-Aleman, Eliel; Duff, Martine C.; Hunter, Doug B.; Burger, Arnold; Groza, Michael; Buliga, Vladimir; Black, David R. (SRNL); (NIST); (Fisk U)

2008-12-08T23:59:59.000Z

229

POLARIZATION STUDIES OF CdZnTe DETECTORS USING SYNCHROTRON X-RAY RADIATION.  

Science Conference Proceedings (OSTI)

New results on the effects of small-scale defects on the charge-carrier transport in single-crystal CdZnTe (CZT) material were produced. We conducted detailed studies of the role of Te inclusions in CZT by employing a highly collimated synchrotron x-ray radiation source available at Brookhaven's National Synchrotron Light Source (NSLS). We were able to induce polarization effects by irradiating specific areas with the detector. These measurements allowed the first quantitative comparison between areas that are free of Te inclusions and those with a relatively high concentration of inclusions. The results of these polaration studies will be reported.

CAMARDA,G.S.; BOLOTNIKOV, A.E.; CUI, Y.; HOSSAIN, A.; JAMES, R.B.

2007-07-01T23:59:59.000Z

230

Synchrotron X-ray Based Characterization of CdZnTe Crystals  

Science Conference Proceedings (OSTI)

Synthetic CdZnTe (CZT) crystals can be used for the room temperature-based detection of gamma radiation. Structural/morphological heterogeneities within CZT, such as secondary phases (namely, precipitates and inclusions), can negatively affect detector performance. We used a synchrotron-based x-ray technique, specifically extended x-ray absorption fine-structure (EXAFS) spectroscopy, to determine whether there are differences on a local structural level between intact CZT of high and low radiation detector performance. These studies were complemented by data on radiation detector performance and transmission infrared (IR) imaging. The EXAFS studies revealed no detectable local structural differences between the two types of CZT materials.

Duff,M.; Hunter, D.; Nuessle, P.; Black, D.; Burdette, H.; Woicik, J.; Burger, A.; Groza, M.

2007-01-01T23:59:59.000Z

231

One-photon band gap engineering of borate glass doped with ZnO for photonics applications  

SciTech Connect

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.

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

232

Reduction of surface leakage current by surface passivation of CdZn Te and other materials using hyperthermal oxygen atoms  

DOE Patents (OSTI)

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.

Hoffbauer, Mark A. (Los Alamos, NM); Prettyman, Thomas H. (Los Alamos, NM)

2001-01-01T23:59:59.000Z

233

Single phase formation of Co-implanted ZnO thin films by swift heavy ion irradiation: Optical studies  

SciTech Connect

Low temperature photoluminescence and optical absorption studies on 200 MeV Ag{sup +15} ion irradiated Co-implanted ZnO thin films were studied. The Co clusters present in as implanted samples were observed to be dissolved using 200 MeV Ag{sup +15} ion irradiation with a fluence of 1x10{sup 12} ions/cm{sup 2}. The photoluminescence spectrum of pure ZnO thin film was characterized by the I{sub 4} peak due to the neutral donor bound excitons and the broad green emission. The Co-doped ZnO films show three sharp levels and two shoulders corresponding to 3t{sub 2g} and 2e{sub g} levels of crystal field splitted Co d orbitals, respectively. The ultraviolet-visible absorption spectroscopy also shows the systematic variation of band gap after 200 MeV Ag{sup +15} ion irradiation.

Kumar, Ravi; Singh, Fouran; Angadi, Basavaraj; Choi, Ji-Won; Choi, Won-Kook; Jeong, Kwangho; Song, Jong-Han; Khan, M. Wasi; Srivastava, J. P.; Kumar, Ajay; Tandon, R. P. [Materials Science Division, Inter-University Accelerator Centre, P.O. Box 10502, Aruna Asaf Ali Marg, New Delhi 110067 (India); Thin Films Materials Research Center, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul 130-650 (Korea, Republic of); Institute of Physics and Applied Physics, Yonsei University, Shincheon-dong 134, Seoul 120-749 (Korea, Republic of); Advanced Analysis Center, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul 130-650 (Korea, Republic of); Department of Physics, Aligarh Muslim University, Aligarh 202002 (India); Department of Physics and Astrophysics, Delhi University, Delhi 110007 (India)

2006-12-01T23:59:59.000Z

234

Ferromagnetism and suppression of metallic clusters in Fe implanted ZnO -- a phenomenon related to defects?  

SciTech Connect

We investigated ZnO(0001) single crystals annealed in high vacuum with respect to their magnetic properties and cluster formation tendency after implant-doping with Fe. While metallic Fe cluster formation is suppressed, no evidence for the relevance of the Fe magnetic moment to the observed ferromagnetism was found. The latter along with the cluster suppression is discussed with respect to defects in the ZnO host matrix, since the crystalline quality of the substrates was lowered due to the preparation as observed by x-ray diffraction.

Arenholz, Elke; Zhou, S.; Potzger, K.; Talut, G.; Reuther, H.; Kuepper, K.; Grenzer, J.; Xu, Q.; Mucklich, A.; Helm, M.; Fassbender, J.; Arenholz, E.

2008-03-12T23:59:59.000Z

235

Search for double beta decay of Zinc and Tungsten with the help of low-background ZnWO4 crystal scintillators  

E-Print Network (OSTI)

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.

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

236

Formation behavior of Be{sub x}Zn{sub 1-x}O alloys grown by plasma-assisted molecular beam epitaxy  

SciTech Connect

We report the phase formation behavior of Be{sub x}Zn{sub 1-x}O alloys grown by plasma-assisted molecular beam epitaxy. We find the alloy with low- and high-Be contents could be obtained by alloying BeO into ZnO films. X-ray diffraction measurements shows the c lattice constant value shrinks, and room temperature absorption shows the energy band-gap widens after Be incorporated. However, the alloy with intermediate Be composition are unstable and segregated into low- and high-Be contents BeZnO alloys. We demonstrate the phase segregation of Be{sub x}Zn{sub 1-x}O alloys with intermediate Be composition resulted from large internal strain induced by large lattice mismatch between BeO and ZnO.

Chen, Mingming; Zhu, Yuan; Su, Longxing; Zhang, Quanlin; Chen, Anqi; Ji, Xu; Xiang, Rong; Gui, Xuchun; Wu, Tianzhun [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China)] [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Pan, Bicai [Department of Physics and Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China)] [Department of Physics and Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Tang, Zikang [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China) [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)

2013-05-20T23:59:59.000Z

237

Experimental and theoretical study of the energy loss of C and O in Zn  

SciTech Connect

We present a combined experimental-theoretical study of the energy loss of C and O ions in Zn in the energy range 50-1000 keV/amu. This contribution has a double purpose, experimental and theoretical. On the experimental side, we present stopping power measurements that fill a gap in the literature for these projectile-target combinations and cover an extended energy range, including the stopping maximum. On the theoretical side, we make a quantitative test on the applicability of various theoretical approaches to calculate the energy loss of heavy swift ions in solids. The description is performed using different models for valence and inner-shell electrons: a nonperturbative scattering calculation based on the transport cross section formalism to describe the Zn valence electron contribution, and two different models for the inner-shell contribution: the shellwise local plasma approximation (SLPA) and the convolution approximation for swift particles (CasP). The experimental results indicate that C is the limit for the applicability of the SLPA approach, which previously was successfully applied to projectiles from H to B. We find that this model clearly overestimates the stopping data for O ions. The origin of these discrepancies is related to the perturbative approximation involved in the SLPA. This shortcoming has been solved by using the nonperturbative CasP results to describe the inner-shell contribution, which yields a very good agreement with the experiments for both C and O ions.

Cantero, E. D.; Lantschner, G. H.; Arista, N. R. [Centro Atomico Bariloche and Instituto Balseiro, Comision Nacional de Energia Atomica, 8400 San Carlos de Bariloche (Argentina); Montanari, C. C.; Miraglia, J. E. [Instituto de Astronomia y Fisica del Espacio (CONICET-UBA), Buenos Aires (Argentina); Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires (Argentina); Behar, M.; Fadanelli, R. C. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Avenida Bento Goncalves 9500, Porto Alegre-RS (Brazil)

2011-07-15T23:59:59.000Z

238

Performances of a large mass ZnSe bolometer to search for rare events  

E-Print Network (OSTI)

Scintillating bolometers of ZnSe are the baseline choice of the LUCIFER experiment, whose aim is to observe the neutrinoless double beta decay of 82Se. The independent read-out of the heat and scintillation signals allows to identify and reject alpha particle interactions, the dominant background source for bolometric detectors. In this paper we report the performances of a ZnSe crystal operated within the LUCIFER R&D. We measured the scintillation yield, the energy resolution and the background in the energy region where the signal from neutrinoless double beta decay of 82Se is expected with an exposure of 9.4 kg x days. With a newly developed analysis algorithm we improved the rejection of alpha events, and we estimated the increase in energy resolution obtained by the combination of the heat and light signals. For the first time we measured the light emitted by nuclear recoils, and found it to be compatible with zero. We conclude that the discrimination of nuclear recoils from beta/gamma interactions in the WIMPs energy region is possible, but low-noise light detectors are needed.

J. W. Beeman; F. Bellini; L. Cardani; N. Casali; I. Dafinei; S. Di Domizio; F. Ferroni; L. Gironi; A. Giuliani; S. Nagorny; F. Orio; L. Pattavina; G. Pessina; G. Piperno; S. Pirro; E. Previtali; C. Rusconi; C. Tomei; M. Vignati

2013-03-17T23:59:59.000Z

239

SeZnSb alloy and its nano tubes, graphene composites properties  

Science Conference Proceedings (OSTI)

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.

Singh, Abhay Kumar [Department of Physics, Indian Institute of Physics, Bangalore-560012 (India)

2013-04-15T23:59:59.000Z

240

Effect of neodymium doping on structure, electrical and optical properties of nanocrystalline ZnO  

SciTech Connect

In this paper, we report effect of Nd doping on structure, electrical and optical properties of nanocrystalline ZnO prepared through a modified ceramic route. The X-ray diffraction and transmission electron microscopy studies reveal that annealed samples are single phase, pure nanocrystalline ZnO. The optical band gap for different compositions, estimated from ultraviolet-visible spectroscopy study, shows a little increasing tendency while doped with Nd for the samples annealed at lower temperature. The dc electrical conductivity of the samples decreases with the increase in Nd concentration. The ac electrical measurements prove the hopping conduction as the dominant mechanism. The results are being explained on the basis of band structural change due to Nd doping in the host lattice and by Correlated Barrier Hopping model. - Highlights: Black-Right-Pointing-Pointer Particle size increases when it is doped (from XRD). Black-Right-Pointing-Pointer XRD peak shifted to lower angle when doped. Black-Right-Pointing-Pointer The dc conductivity decreases with the increase of Nd dopant concentrations. Black-Right-Pointing-Pointer The temperature dependent ac conductivity follows the universal power law.

Roy, B.; Chakrabarty, S. [Department of Physics, University of Burdwan, Burdwan-713 104 (India); Mondal, O., E-mail: oindrila.rng@gmail.com [Department of Physics, University of Burdwan, Burdwan-713 104 (India); Pal, M., E-mail: m_pal@cmeri.res.in [CSIR-Central Mechanical Engineering Research Institute, Durgapur-713 209 (India); Dutta, A., E-mail: dutta_abhigyan@yahoo.co.in [Department of Physics, University of Burdwan, Burdwan-713 104 (India)

2012-08-15T23:59:59.000Z

Note: This page contains sample records for the topic "zn zurn ot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Raman spectroscopic study of carbon nanotubes prepared using Fe/ZnO-palm olein-chemical vapour deposition  

Science Conference Proceedings (OSTI)

Multiwalled carbon nanotubes (MWCNTs) were synthesized using Fe/ZnO catalyst by a dual-furnace thermal chemical vapor deposition (CVD) method at 800-1000°C using nitrogen gas with a constant flow rate of 150 sccm/min as a gas carrier. Palm olein ...

Syazwan Afif Mohd Zobir; Suriani Abu Bakar; Saifollah Abdullah; Zulkarnain Zainal; Siti Halimah Sarijo; Mohamad Rusop

2012-01-01T23:59:59.000Z

242

Preparation, characterization of the Ta-doped ZnO nanoparticles and their photocatalytic activity under visible-light illumination  

SciTech Connect

This paper describes a novel catalyst of the Ta-doped ZnO nanocrystals prepared by a modified polymerizable complex method using the water-soluble tantalum precursor as the sources of Ta. The catalysts were characterized by means of various analytical techniques as a function of Ta content (x=0-4 mol%) systematically. A remarkable advantage of the results was confirmed that dopant Ta enhanced the visible-light absorption of ZnO and the low-solubility tantalum doping could restrain the growth of crystal and minish the particle size. The relationship between the physicochemical property and the photocatalytic performance was discussed, and it was found that the photocatalytic activity in the photochemical degradation of methylene blue under visible-light irradiation (lambda>=420 nm) was dependent on the contents of the dopant, which could affect the particle size, concentration of surface hydroxyl groups and active hydrogen-related defect sites, and the visible-light absorption. The highest photocatalytic activity was obtained for the 1.0 mol% Ta-doped ZnO sample. - Graphical abstract: The addition of the tantalum into ZnO prepared by a modified polymerizable complex method not only restrains the growth of crystal, minish the particle size, but also changes the nanocrystal morphology.

Kong Jizhou [National Laboratory of Solid State Microstructures, Materials Science and Engineering Department, Nanjing University, Nanjing 210093 (China); Li Aidong, E-mail: adli@nju.edu.c [National Laboratory of Solid State Microstructures, Materials Science and Engineering Department, Nanjing University, Nanjing 210093 (China); Zhai Haifa; Gong Youpin; Li Hui; Wu Di [National Laboratory of Solid State Microstructures, Materials Science and Engineering Department, Nanjing University, Nanjing 210093 (China)

2009-08-15T23:59:59.000Z

243

Laser irradiation effects on the CdTe/ZnTe quantum dot structure studied by Raman and AFM spectroscopy  

SciTech Connect

Micro-Raman spectroscopy has been applied to investigate the impact of laser irradiation on semiconducting CdTe/ZnTe quantum dots (QDs) structures. A reference sample (without dots) was also studied for comparison. Both samples were grown by molecular beam epitaxy technique on the p-type GaAs substrate. The Raman spectra have been recorded for different time of a laser exposure and for various laser powers. The spectra for both samples exhibit peak related to the localized longitudinal (LO) ZnTe phonon of a wavenumber equal to 210 cm{sup -1}. For the QD sample, a broad band corresponding to the LO CdTe phonon related to the QD-layer appears at a wavenumber of 160 cm{sup -1}. With increasing time of a laser beam exposure and laser power, the spectra get dominated by tellurium-related peaks appearing at wavenumbers around 120 cm{sup -1} and 140 cm{sup -1}. Simultaneously, the ZnTe surface undergoes rising damage, with the formation of Te aggregates at the pinhole edge as reveal atomic force microscopy observations. Local temperature of irradiated region has been estimated from the anti-Stokes/Stokes ratio of the Te modes intensity and it was found to be close or exceeding ZnTe melting point. Thus, the laser damage can be explained by the ablation process.

Zielony, E.; Placzek-Popko, E.; Henrykowski, A.; Gumienny, Z.; Kamyczek, P.; Jacak, J. [Institute of Physics, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland); Nowakowski, P.; Karczewski, G. [Institute of Physics, Polish Academy of Sciences, al. Lotnikow 32/46, 02-668 Warsaw (Poland)

2012-09-15T23:59:59.000Z

244

Particle size effect on TL emission of ZnS nanoparticles and determination of its kinetic parameters  

Science Conference Proceedings (OSTI)

Nanoparticles have large surface area, and most of the ions are lying on its surface. Could these surface ions be contributed in thermoluminescence emission or enhanced nonradiative transition? In view of this, we have prepared small sizes of ZnS nanoparticles ...

L. Robindro Singh; S. Dorendrajit Singh

2012-01-01T23:59:59.000Z

245

Measuring charge trap occupation and energy level in CdSe/ZnS quantum dots using a scanning tunneling microscope  

E-Print Network (OSTI)

We use a scanning tunneling microscope to probe single-electron charging phenomena in individual CdSe/ZnS (core/shell) quantum dots (QDs) at room temperature. The QDs are deposited on top of a bare Au thin film and form a ...

Bulovic, Vladimir

246

Formation of ZnTe:Cu/Ti Contacts at High Temperature for CdS/CdTe Devices: Preprint  

DOE Green Energy (OSTI)

We study the performance of CdS/CdTe thin-film devices contacted with ZnTe:Cu/Ti of various thickness at a higher-than-optimum temperature of {approx}360 C. At this temperature, optimum device performance requires the same thickness of ZnTe:Cu as for similar contacts formed at a lower temperature of 320 C. C-V analysis indicates that a ZnTe:Cu layer thickness of {approx}< 0.5 mu m does not yield the degree of CdTe net acceptor concentration necessary to reduce space charge width to its optimum value for n-p device operation. The thickest ZnTe:Cu layer investigated (1 mu m) yields the highest CdTe net acceptor concentration, lowest value of Jo, and highest Voc. However, performance is limited for this device by poor fill factor. We suggest poor fill factor is due to Cu-related acceptors compensating donors in CdS.

Gessert, T. A.; Asher, S.; Johnston, S.; Duda, A.; Young, M. R.; Moriarty, T.

2006-05-01T23:59:59.000Z

247

Factors Affecting the Hydrogen Environment Assisted Cracking Resistance of an Al-Zn-Mg-(Cu) Alloy  

DOE Green Energy (OSTI)

It is well established that Al-Zn-Mg-(Cu) aluminum alloys are susceptible to hydrogen environment assisted cracking (HEAC) when exposed to aqueous environments. In Al-Zn-Mg-Cu alloys, overaged tempers are commonly used to increase HEAC resistance at the expense of strength. Overaging has little benefit in low copper alloys. However, the mechanism or mechanisms by which overaging imparts HEAC resistance is poorly understood. The present research investigated hydrogen uptake, diffusion, and crack growth rate in 90% relative humidity (RH) air for both a commercial copper bearing Al-Zn-Mg-Cu alloy (AA 7050) and a low copper variant of this alloy in order to better understand the factors which affect HEAC resistance. Experimental methods used to evaluate hydrogen concentrations local to a surface and near a crack tip include nuclear reaction analysis (NRA), focused ion beam, secondary ion mass spectroscopy (FIB/SIMS) and thermal desorption spectroscopy (TDS). When freshly bared coupons of AA 7050 are exposed to 90 C, 90% RH air, hydrogen ingress follows inverse-logarithmic-type kinetics and is equivalent for underaged (HEAC susceptible) and overaged (HEAC resistant) tempers. However, when the native oxide is allowed to form (24 hrs in 25 C, 40% RH lab air) prior to exposure to 90 C, 90% RH air, underaged alloy shows significantly greater hydrogen ingress than the overaged alloy. Humid air is a very aggressive environment producing local ({approx}1{micro}m) hydrogen concentrations in excess of 10,000 wt. ppm at 90 C. In the copper bearing alloy, overaging also effects the apparent diffusivity of hydrogen. As AA 7050 is aged from underaged {yields} peak aged {yields} overaged, the activation energy for hydrogen diffusion increases and the apparent diffusivity for hydrogen decreases, In the low copper alloy, overaging has little effect on hydrogen diffusion. Comparison of the apparent activation energies for hydrogen diffusion and for K independent (stage II) crack growth rate in 90% RH air between 25 and 90 C indicates that hydrogen transport kinetics are responsible for the decreased crack growth rate of overaged AA 7050 relative to the peak aged temper.

G.A. Young; J.R. Scully

2001-09-12T23:59:59.000Z

248

EXCITATION AND DETERIORATION OF THE LUMINESCENCE OF CaWO$sub 4$ AND ZnS(Ag) BY IONS  

SciTech Connect

The luminescence response of ZnS(Ag) and CaWO/sub 4/ to ion bombardment and the deterioration of luminescence under prolonnged irradiation was determined as a function of ion energy E, ion mass M/sub 1/ and beam density I. The variation of light output with ion energy is of the form J2 = C x (E E/sub o/)/ sub n/ with n = 2 (ZnS(Ag)) or lower values (CaWO/sub 4/). The luminescence response to ions of various mass was found to decrease generally with growing mass, but to be nearly constant to ions of middle atomic weinght (ZnS(Ag)). The luminescence efficiency, caused by ions of energy greater than 5 kev, is indfpfndent of beam density within the whole range studied (maximum 3 x 10/sup -// sup 3/ A cm/sup -//sup 3/), but it diminishes in the case E = 5 kfv for values of 1 above 6 x 10/sup -//sup 9/ A cm/sup -//sup 2/ The deterioration efffet grows, except in the case of He/sup +/ ions, the lightest ions used. with ion energy. It also increases by substituting Ne/sup +/ for He/sup +/ ions, but remains nearly independent of mass (CaWO/sub 4/) or diminishes with growinng ion-mass (ZnS(Ang)), if the ions are heavier than Ne/sup +/ ions. Increasing beam density leads to a reduced deterioratioa of ZnS(Ang) luminescence, yet has no influence on that of CaWO/sub 4/. (auth)

Doll, G.

1961-01-01T23:59:59.000Z

249

Transparent conducting impurity-doped ZnO thin films prepared using oxide targets sintered by millimeter-wave heating  

Science Conference Proceedings (OSTI)

The preparation of transparent conducting impurity-doped ZnO thin films by both pulsed laser deposition (PLD) and magnetron sputtering deposition (MSD) using impurity-doped ZnO targets sintered with a newly developed energy saving millimeter-wave (28 GHz) heating technique is described. Al-doped ZnO (AZO) and V-co-doped AZO (AZO:V) targets were prepared by sintering with various impurity contents for 30 min at a temperature of approximately 1250 degree sign C in an air or Ar gas atmosphere using the millimeter-wave heating technique. The resulting resistivity and its thickness dependence obtainable in thin films prepared by PLD using millimeter-wave-sintered AZO targets were comparable to those obtained in thin films prepared by PLD using conventional furnace-sintered AZO targets; a low resistivity on the order of 3x10{sup -4} {Omega} cm was obtained in AZO thin films prepared with an Al content [Al/(Al+Zn) atomic ratio] of 3.2 at. % and a thickness of 100 nm. In addition, the resulting resistivity and its spatial distribution on the substrate surface obtainable in thin films prepared by rf-MSD using a millimeter-wave-sintered AZO target were almost the same as those obtained in thin films prepared by rf-MSD using a conventional powder AZO target. Thin films prepared by PLD using millimeter-wave-sintered AZO:V targets exhibited an improved resistivity stability in a high humidity environment. Thin films deposited with a thickness of approximately 100 nm using an AZO:V target codoped with an Al content of 4 at. % and a V content [V/(V+Zn) atomic ratio] of 0.2 at. % were sufficiently stable when long-term tested in air at 90% relative humidity and 60 degree sign C.

Minami, Tadatsugu; Okada, Kenji; Miyata, Toshihiro; Nomoto, Juni-chi; Hara, Youhei; Abe, Hiroshi [Optoelectronic Device System R and D Center, Kanazawa Institute of Technology, 7-1 Ohgigaoka, Nonoichi, Ishikawa 921-8501 (Japan); Fuji Dempa Kogyo Co. Ltd., 26 Kasuminosato, Ami, Inashiki, Ibaragi 300-0315 (Japan)

2009-07-15T23:59:59.000Z

250

Co-assembly of Zn(SPh){sub 2} and organic linkers into helical and zig-zag polymer chains  

SciTech Connect

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.

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

251

The Effect of Zn Addition on the Oxidation State of Cobalt in Co/ZrO2 Catalysts  

Science Conference Proceedings (OSTI)

The effect of Zn promotion on the activity and selectivity of Co/ZrO{sub 2} catalysts for ethanol steam reforming was investigated. The catalysts were synthesized by incipient wetness impregnation and characterized using BET measurements, temperature programmed reduction, X-ray diffraction, transmission electron microscopy, and X-ray electron spectroscopy. Compared to Co/ZrO{sub 2} catalyst, a higher ethanol conversion and a lower CH{sub 4} selectivity were observed for the Co/ZrO{sub 2} catalyst promoted with Zn. It was found that addition of Zn inhibits the oxidation of metallic cobalt (Co{sup 0}) particles, which results in a higher ratio of Co{sup 0}/Co{sup 2+} present in the Zn promoted Co/ZrO{sub 2} catalyst. These results suggest that metallic cobalt (Co{sup 0}) is responsible for ethanol conversion via ethanol dehydrogenation whereas Co{sup 2+} plays a role in the CH{sub 4} formation. For both catalysts, the experimental results show that CH4 is mainly produced via CO and/or CO{sub 2} methanation. TPR measurements, on the other hand, show Zn addition inhibits the reduction of Co{sup 2+} and Co{sup 3+}, which would mislead the conclusion that oxidized Co is required to reduce the CH{sub 4} formation. Therefore, TPR may not be appropriate to correlate the degree of metal reducibility (in this case Co{sup 0}) with the catalyst activity for reactions such as ethanol steam reforming where oxidizing conditions exist.

Lebarbier, Vanessa MC; Karim, Ayman M.; Engelhard, Mark H.; Wu, Yu; Xu, Bo-Qing; Petersen, Eric J.; Datye, Abhaya K.; Wang, Yong

2011-09-01T23:59:59.000Z

252

Zn-Doped RuO2 Electrocatalyts for Selective Oxygen Evolution: Relationship Between Local Structure and Electrocatalytic Behavior in Chloride Containing Media  

SciTech Connect

Nanocrystalline electrocatalytically active materials of chemical composition Ru{sub 1-x}Zn{sub x}O{sub 2} (0 < x < 0.3) were synthesized by freeze-drying technique. The diffraction patterns of the prepared samples corresponded to single-phase rutile type oxides.Local structure of the Ru{sub 1-x}Zn{sub x}O{sub 2} based on refinement of Ru K and Zn K edge EXAFS functions shows clustering of the Zn ions in the blocks with ilmenite structure intergrowing with Ru-rich rutile blocks. Ru{sub 1-x}Zn{sub x}O{sub 2} oxides are selective catalysts for anodic oxygen evolution. The selectivity toward oxygen evolution in the presence of chlorides is affected by the actual Zn content and can be ascribed to structural hindrance of the formation of the surface peroxo group based active sites for chlorine evolution. The selectivity toward oxygen evolution in presence of chlorides is accompanied by the drop of the total activity, which gets more pronounced with increasing Zn content.

V Petrykin; K Macounova; J Franc; O Shlyakhtin; M Klementova; S Mukerjee; p Krtil

2011-12-31T23:59:59.000Z

253

Zn-impurity effects on quasiparticle scattering in La2-xSrxCuO4 studied by angle-resolved photoemission spectroscopy  

SciTech Connect

Angle-resolved photoemission measurements were performed on Zn-doped La{sub 2-x}Sr{sub x}CuO{sub 4} to investigate the effects of Zn impurities on the low-energy electronic structure. The Zn-impurity-induced increase in the quasiparticle width in momentum distribution curves (MDCs) is approximately isotropic on the entire Fermi surface and energy independent near the Fermi level (EF). The increase in the MDC width is consistent with the increase in the residual resistivity due to the Zn impurities if we assume the carrier number to be 1-x for x=0.17 and the Zn impurity to be a potential scatterer close to the unitarity limit. For x=0.03, the residual resistivity is found to be higher than that expected from the MDC width, and the effects of antiferromagnetic fluctuations induced around the Zn impurities are discussed. The leading edges of the spectra near ({pi},0) for x=0.17 are shifted toward higher energies relative to E{sub F} with Zn substitution, indicating a reduction in the superconducting gap.

Yoshida, T.

2010-02-24T23:59:59.000Z

254

Cation dopant distributions in nanostructures of transition-metal doped ZnO:Monte Carlo simulations  

SciTech Connect

The path from trace doping to solid solution formation involves an intermediate regime in which the doping level is a few to several atomic percent. In this regime, dopant-dopant interactions, which are driven by the spatial arrangement of dopants, are critical factors in determining the resulting properties. Conventional wisdom counts on simple probabilistic methods for predicting dopant distributions. Here, we use Monte Carlo simulations to show that widely used, straightforward statistical models, such as that of Behringer1, are accurate only in the limit of infinitesimally small surface–to-volume ratio. For epitaxial films and nanoparticles, where much of the current interest resides, dopant distributions depend strongly on the surface-to-volume ratio. We present empirical expressions that accurately predict dopant bonding configurations as a function of film or particle size, shape and dopant concentration for doped ZnO, a material of particular interest in semiconductor spintronics.

Droubay, Timothy; Kaspar, Tiffany C.; Kaspar, Bryce P.; Chambers, Scott A.

2009-02-01T23:59:59.000Z

255

Magnetic motion capture system using LC resonant magnetic marker composed of Ni-Zn ferrite core  

SciTech Connect

We have proposed a magnetic motion capture system using an LC resonant magnetic marker. The proposed system is composed of an exciting coil, an LC marker, and a 5x5-matrix search coil array (25 search coils). The LC marker is small and has a minimal circuit with no battery and can be driven wirelessly by the action of electromagnetic induction. It consists of a Ni-Zn ferrite core (3 mm{phi}x10 mm) with a wound coil and a chip capacitor, forming an LC series circuit with a resonant frequency of 186 kHz. The relative position accuracy of the system is less than 1 mm within the area of 100 mm{sup 3} up to 150 mm from the search coil array. Compared with dc magnetic systems, the proposed system is applicable for precision motion capture in optically isolated spaces without magnetic shielding because the system is not greatly influenced by earth field noise.

Hashi, S.; Toyoda, M.; Ohya, M.; Okazaki, Y.; Yabukami, S.; Ishiyama, K.; Arai, K. I. [Department of Materials Science and Technology, Gifu University, 1-1 Yanagido, Gifu 501-1193 (Japan); Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)

2006-04-15T23:59:59.000Z

256

Analytical model for event reconstruction in coplanar grid CdZnTe detectors  

E-Print Network (OSTI)

Coplanar-grid (CPG) particle detectors were designed for materials such as CdZnTe (CZT) in which charge carriers of only one sign have acceptable transport properties. The presence of two independent anode signals allows for a reconstruction of deposited energy based on the difference between the two signals, and a reconstruction of the interaction depth based on the ratio of the amplitudes of the sum and difference of the signals. Energy resolution is greatly improved by modifying the difference signal with an empirically determined weighting factor to correct for the effects of electron trapping. In this paper is introduced a modified interaction depth reconstruction formula which corrects for electron trapping utilizing the same weighting factor used for energy reconstruction. The improvement of this depth reconstruction over simpler formulas is demonstrated. Further corrections due to the contribution of hole transport to the signals are discussed.

Matthew Fritts; Jürgen Durst; Thomas Göpfert; Thomas Wester; Kai Zuber

2012-11-28T23:59:59.000Z

257

Analytical model for event reconstruction in coplanar grid CdZnTe detectors  

E-Print Network (OSTI)

Coplanar-grid (CPG) particle detectors were designed for materials such as CdZnTe (CZT) in which charge carriers of only one sign have acceptable transport properties. The presence of two independent anode signals allows for a reconstruction of deposited energy based on the difference between the two signals, and a reconstruction of the interaction depth based on the ratio of the amplitudes of the sum and difference of the signals. Energy resolution is greatly improved by modifying the difference signal with an empirically determined weighting factor to correct for the effects of electron trapping. In this paper is introduced a modified interaction depth reconstruction formula which corrects for electron trapping utilizing the same weighting factor used for energy reconstruction. The improvement of this depth reconstruction over simpler formulas is demonstrated. Further corrections due to the contribution of hole transport to the signals are discussed.

Fritts, Matthew; Göpfert, Thomas; Wester, Thomas; Zuber, Kai

2012-01-01T23:59:59.000Z

258

Low-lying structure of neutron-rich Zn and Ga isotopes  

Science Conference Proceedings (OSTI)

Low-lying states of even-even Zn and odd-mass Ga nuclei with neutron numbers between 42 and 50 have been calculated within the framework of the SDG-pair approximation of the nuclear shell model. We employ a monopole and quadrupole pairing plus quadrupole-quadrupole interaction with optimized parameters, which are assumed to be constants for nuclei with the same proton number or neutron number. We calculate low-lying level schemes, electric quadrupole and magnetic dipole moments, and E2 and M1 transition rates. Reasonable agreement is achieved between the calculated results and experimental data. Dominant configurations in the ground states of odd-mass Ga nuclei are discussed in terms of pair correlations. The weak-coupling picture for some states of odd-mass Ga nuclei is studied.

Jiang, H. [School of Arts and Sciences, Shanghai Maritime University, Shanghai 200135 (China); Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Fu, G. J.; Arima, A. [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Zhao, Y. M. [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 730000 (China); CCAST, World Laboratory, P.O. Box 8730, Beijing 100080 (China)

2011-09-15T23:59:59.000Z

259

Co-Evaporated Cu2ZnSnSe4 Films and Devices  

DOE Green Energy (OSTI)

The use of vacuum co-evaporation to produce Cu2ZnSnSe4 photovoltaic devices with 9.15% total-area efficiency is described. These new results suggest that the early success of the atmospheric techniques for kesterite photovoltaics may be related to the ease with which one can control film composition and volatile phases, rather than a fundamental benefit of atmospheric conditions for film properties. The co-evaporation growth recipe is documented, as is the motivation for various features of the recipe. Characteristics of the resulting kesterite films and devices are shown in scanning electron micrographs, including photoluminescence, current-voltage, and quantum efficiency. Current-voltage curves demonstrate low series resistance without the light-dark cross-over seen in many devices in the literature. Band gap indicated by quantum efficiency and photoluminescence is roughly consistent with that expected from first principles calculation.

Repins, I.; Beall, C.; Vora, N.; DeHart, C.; Kuciauskas, D.; Dippo, P.; To, B.; Mann, J.; Hsu, W. C.; Goodrich, A.; Noufi, R.

2012-06-01T23:59:59.000Z

260

Characterization of detector grade CdZnTe material from Redlen Technologies  

Science Conference Proceedings (OSTI)

CdZnTe (or CZT) crystals can be used in a variety of detector-type applications. This large band gap material shows great promise for use as a gamma radiation spectrometer. Historically, the performance of CZT has typically been adversely affected by point defects, structural and compositional heterogeneities within the crystals, such as twinning, pipes, grain boundaries (polycrystallinity) and secondary phases (SP). The synthesis of CZT material has improved greatly with the primary performance limitation being attributed to mainly SP. In this presentation, we describe the extensive characterization of detector grade material that has been treated with post growth annealing to remove the SPs. Some of the analytical methods used in this study included polarized, cross polarized and transmission IR imaging, I-V curves measurements, synchrotron X-ray topography and electron microscopy.

Duff, Martine C.; Burger, Arnold; Groza, Michael; Buliga, Vladimir; Bradley, John P.; Dai, Zurong R.; Teslich, Nick; Black, David R.; Awadalla, Salah A.; Mackenzie, Jason; Chen, Henry (Redlen); (SRNL); (LLNL); (NIST); (Fisk U)

2008-10-24T23:59:59.000Z

Note: This page contains sample records for the topic "zn zurn ot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Effect of Extended Defects in Planar and Pixelated CdZnTe Detectors  

Science Conference Proceedings (OSTI)

We evaluated a spectroscopy-grade 15 x 15 x 7 mm{sup 3} CdZnTe (CZT) crystal with a high {mu}{tau}-product, > 10{sup -2} cm{sup 2}/V, but impaired by microscopic extended defects, such as walls of dislocations, low-angle and sub-grain boundaries, and Te inclusions. First, we evaluated a planar detector fabricated from this crystal using a Microscale X-ray Detector Mapping (MXDM) technique. Then, we fabricated from the same crystal a pixel detector to study local non-uniformities of the electric field. The measured X-ray response maps confirmed the presence of non-uniformities in the charge transport, and they showed that the global- and local-distortions of the internal E-field correlated to the extended defects and space-charge buildup on the side surfaces.

C Camarda; K Andreini; A Bolotnikov; Y Cui; A Hossain; R Gul; K Kim; L Marchini; L Xu; et al.

2011-12-31T23:59:59.000Z

262

Correlations Between Crystal Defects and Performance of CdZnTe Detectors  

Science Conference Proceedings (OSTI)

Poor crystallinity remains a major problem affecting the availability and cost of CdZnTe (CZT) detectors. Point defects are responsible for small gradual charge loss and correlated with the electron clouds' drift times, which allows electronic correction of the output signals to achieve high spectral-resolution even with large-volume CZT detectors. In contrast, extended defects causes significant charge losses, which typically are uncorrelated, and, thus, result in much greater fluctuations of the output signals that cannot be corrected. Although extended defects do not affect all the interaction events, their fraction rapidly increases with the crystal's thickness and volume. In this paper, we summarize our recent results from testing CZT material and detectors that emphasize the particular roles of two types of extended defects, and their contributions to the device's overall performance.

A Bolotnikov; S Babalola; G Camarda; Y Cui; R Gul; S Egarievwe; P Fochuk; M Fuerstnau; J Horace; et al.

2011-12-31T23:59:59.000Z

263

Performance Characteristics of Frisch-Ring CdZnTe Detectors  

Science Conference Proceedings (OSTI)

The performance characteristics of Frisch-ring CdZnTe (CZT) detectors are described and compared with other types of CZT devices. The Frisch-ring detector is a bar-shaped CZT crystal with a geometrical aspect ratio of /spl sim/1:2. The side surfaces of the detector are coated with an insulating layer followed by a metal layer deposited directly upon the insulator. The simple design operates as a single-carrier device. Despite the simplicity of this approach, its performance depends on many factors that are still not fully understood. We describe results of testing several detectors fabricated from CZT material produced by different vendors and compare the results with numerical simulations of these devices.

Bolotnikov,A.; Camarda, G.; Carini, G.; Fiederle, M.; Li, L.; McGregor, D.; McNeil, W.; Wright, G.; James, R.

2006-01-01T23:59:59.000Z

264

Projectile fragmentation of radioactive beams of {sup 68}Ni, {sup 69}Cu, and {sup 72}Zn  

Science Conference Proceedings (OSTI)

The fragment production cross sections of secondary neutron-rich beams of {sup 68}Ni, {sup 69}Cu, and {sup 72}Zn isotopes at energies of about 95A MeV have been measured. We compare the measured cross sections to EPAX, an empirical parametrization of fragmentation cross sections. A reasonable agreement of the experimental data and EPAX predictions suggests that an EPAX parametrization used for stable beams seems to be valid for unstable neutron-rich ion beams. EPAX tends to overestimate the yields of neutron-rich isotopes. This problem is amplified when neutron-rich radioactive beams are employed, leading to overly optimistic estimates of the production of neutron-rich isotopes.

Lukyanov, S.; Lobastov, S. P.; Tarasov, O. B. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, RU-141980 Dubna, Moscow region (Russian Federation); Mocko, M. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States); Andronenko, L.; Andronenko, M. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); PNPI, Gatchina, Leningrad district RU-188300 (Russian Federation); Bazin, D.; Gade, A. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Famiano, M. A. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Department of Physics, Western Michigan University, Kalamazoo, Michigan 49008 (United States); Lynch, W. G.; Rogers, A. M.; Tsang, M. B.; Zegers, R. G. T. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States); Verde, G. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); INFN, Sezione di Catania, 64 Via Santa Sofia, I-95123 Catania (Italy); Wallace, M. S. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2009-07-15T23:59:59.000Z

265

Synthesis and characterization of nano ZnO rods via microwave assisted chemical precipitation method  

Science Conference Proceedings (OSTI)

A microwave assisted chemical precipitation method has been employed for the synthesis of nano zinc oxide rods by reacting zinc nitrate and potassium hydroxide. The amount of potassium hydroxide was adjusted for three different pHs to achieve ZnO nano rods with varying aspect ratio. The mechanism of growth of nano rods is explained briefly. The average crystallite size of the as synthesized samples was analyzed by means of powder XRD pattern and estimated to vary from 25.6 nm to 43.1 nm. The existence of rods was confirmed using scanning electron microscopy (SEM). The samples were also analyzed using FT-IR. The optical properties of the samples were also studied by means of UV-visible spectra and Room Temperature Photo Luminescence studies. The band gap of the samples was determined from the DRS spectrum. A strong near band emission peaks due to surface defects are observed in the PL spectrum. - Graphical abstract: At the solution pH of 11 and 9, tetrapod-like and flower-like ZnO nano rods were formed along with separated rods respectively due to the formation of activated nuclei of different sizes. Highlights: Black-Right-Pointing-Pointer Increase in alkalinity of the precursor solution results in longer rods. Black-Right-Pointing-Pointer Beyond a saturation limit, the excess of added OH{sup -} ions inhibited the growth of rods. Black-Right-Pointing-Pointer Keeping all parameters the same, the alkalinity can only modify the aspect ratio of the rods and not their morphology.

Uma Sangari, N., E-mail: umasangariselvakumar@gmail.com [Department of Chemistry, S.F.R. College for Women, Sivakasi 626123 (India); Chitra Devi, S. [Department of Chemistry, S.F.R. College for Women, Sivakasi 626123 (India)

2013-01-15T23:59:59.000Z

266

TiO2 Nanotubes with a ZnO Thin Energy Barrier for Improved Current Efficiency of CdSe Quantum-Dot-Sensitized Solar Cells  

Science Conference Proceedings (OSTI)

This paper reports the formation of a thin ZnO energy barrier between a CdSe quantum dot (Q dots) sensitizer and TiO{sub 2} nanotubes (TONTs) for improved current efficiency of Q dot-sensitized solar cells. The formation of a ZnO barrier between TONTs and the Q dot sensitizer increased the short-circuit current under illumination and also reduced the dark current in a dark environment. The power conversion efficiency of Q dot-sensitized TONT solar cells increased by 25.9% in the presence of the ZnO thin layer due to improved charge-collecting efficiency and reduced recombination.

Lee, W.; Kang, S. H.; Kim, J. Y.; Kolekar, G. B.; Sung, Y. E.; Han, S. H.

2009-01-01T23:59:59.000Z

267

Novel ways of depositing ZnTe films by a solution growth technique. Final subcontract report, 1 January 1990--1 January 1992  

DOE Green Energy (OSTI)

An electrochemical process has been successfully developed for the reproducible deposition of ZnTe and copper-doped ZnTe films suitable as transparent ohmic contacts for CdS/CdTe solar cells. The development of this method and optimization of key processing steps in the fabrication of CdS/CdTe/ZnTe:Cu devices has allowed IEC to achieve cell performance results of FF>70% and {eta} {approximately}10%. Preliminary efforts have indicated that the deposition methods investigated are potentially feasible for the formation of other II-VI compounds for use in polycrystalline thin film solar devices and should be the focus of future work.

Birkmire, R.W.; McCandless, B.E.; Yokimcus, T.A.; Mondal, A. [Delaware Univ., Newark, DE (United States). Inst. of Energy Conversion

1992-10-01T23:59:59.000Z

268

The Hybridization of CdSe/ZnS Quantum Dot on InGaN Light-Emitting Diodes for Color Conversion  

Science Conference Proceedings (OSTI)

We have demonstrated the fabrication and characterization of hybrid CdSe/ZnS quantum dot (QD)-InGaN blue LEDs. The chemically synthesized red light (lambda = 623 nm) QD solutions with different concentrations were dropped onto the blue InGaN LEDs with ... Keywords: CdSe/ZnS quantum dots, CdSe/ZnS quantum dots (QDs), InGaN quantum well and hybrid LEDs, InGaN quantum well and hybrid light-emitting diodes

Ying-Chih Chen; Chun-Yuan Huang; Yan-Kuin Su; Wen-Liang Li; Chia-Hsien Yeh; Yu-Cheng Lin

2008-07-01T23:59:59.000Z

269

Tetrahedral-Network Organo-Zincophosphates: Syntheses and Structures of (N(2)C(6)H(14)).Zn(HPO(4))(2).H(2)O, H(3)N(CH(2))(3)NH(3).Zn(2)(HPO(4))(3) and (N(2)C(6)H(14)).Zn(3)(HPO(4))(4)  

SciTech Connect

The solution-mediated syntheses and single crystal structures of (N2C6H14Zn(HPO4)2·H2O (I), H3N(CH2)3NH3·Zn2(HPO4)3 (II), and (N2C6H14Zn3(HPO4)4 (III) are described. These phases contain vertex-sharing Zn04 and HP04 tetrahedra, accompanied by doubly- protonated organic cations. Despite their formal chemical relationship, as members of the series of t·Znn(HP04)n+1 (t= template, n = 1-3), these phases adopt fimdamentally different crystal structures, as one-dimensional, two-dimensional, and three-dimensional Zn04/HP04 networks, for I, II, and III respectively. Similarities and differences to some other zinc phosphates are briefly discussed. Crystal data: (N2C6H14Zn(HP04)2·H20, Mr = 389.54, monoclinic, space group P21/n (No. 14), a = 9.864 (4) Å, b = 8.679 (4) Å, c = 15.780 (3) Å, ? = 106.86 (2)°, V= 1294.2 (8) Å3, Z = 4, R(F) = 4.58%, RW(F) = 5.28% [1055 reflections with I >3?(I)]. H3N(CH2)3NH3·Zn2(HP04)3, Mr = 494.84, monoclinic, space group P21/c (No. 14), a= 8.593 (2)Å, b= 9.602 (2)Å, c= 17.001 (3)Å, ?= 93.571 (8)°, V = 1400.0 (5) Å3, Z = 4, R(F) = 4.09%, RW(F) = 4.81% [2794 reflections with I > 3? (I)]. (N2C6H14Zn3(HP04)4, Mr= 694.25, monoclinic, space group P21/n (No. 14), a = 9.535 (2) Å, b = 23.246 (4)Å, c= 9.587 (2)Å, ?= 117.74 (2)°, V= 1880.8 (8) Å3, Z = 4, R(F) = 3.23%, RW(F) = 3.89% [4255 reflections with 1> 3?(I)].

Chavez, Alejandra V.; Hannooman, Lakshitha; Harrison, William T.A.; Nenoff, Tina M.

1999-05-07T23:59:59.000Z

270

Surface Science Opportunities in the Electronic Structure of ZnO (A Perspective on the Article, "Quantitative Analysis of Surface Donors in ZnO", by D.C. Look)  

SciTech Connect

ZnO is a wide-gap oxide semiconductor of considerable current interest for electronics, optoelectronics, and, possibly, semiconductor spintronics. Through selective electronic doping, ZnO can be a transparent conducting oxide [1], a UV light emitter [2,3], and, when alloyed with a few to several atomic percent of Co, Mn or other transition metals with unpaired d electrons, is squarely at the center of controversy in the field of high-Tc ferromagnetic semiconductors [4]. Despite this range of interests, fundamental aspects of electronic doping in ZnO remain poorly understood. For instance, theoretical calculations suggest that H at either interstitial or substitutional sites is responsible for the persistent n-type conductivity that frustrates efforts to achieve p-type behavior, an essential requirement for the fabrication of pn light emitting diodes and hole-mediated ferromagnetic coupling of Mn dopants [5,6]. Yet, experimental studies do not in general align with this prediction. Another interesting aspect of n-type conduction in ZnO is the appearance of a near-surface conducting channel that appears to be present in bulk crystals [7,8]. Although it has been a few years since the original observation of this phenomenon was described, detailed understanding is lacking. In this paper, David Look presents a transport study aimed at gaining insight into the phenomenon of near-surface conductivity in bulk ZnO. All samples investigated were unintentionally n-type, as is typical. The measured Hall data were interpreted using a two-layer conduction model based on standard charge balance equations. Look fit the temperature dependence of the electron mobility and carrier concentration and extracted the thicknesses of the surface conducting layer, which dominates at lower temperatures, for bulk crystals synthesized by different methods and marketed by different companies. By making reasonable assumptions about the surface acceptor density, the lower limit of the surface conducting layer thickness was extracted from the transport data. From a surface science perspective, two aspects of the investigation are of particular interest: (i) the donor concentration was enhanced by annealing in forming gas, which is 5% H2, and, (ii) despite relatively weak variation in the sheet carrier concentration, the surface conducting layer thickness (dsurf) varied from as large as 28 nm to as small as 1.5 nm, depending on the method of preparation and supplier. The ongoing exploration of this phenomenon begs for the kind of experiments that practitioners of surface, interface and thin-film science can readily conduct. In bulk crystals, is H doping really the cause? Answering this question represents a major challenge because the donor concentration is in the 1017-1018 cm-3 range. Determining the donor identity in this concentration range is a major experimental hurdle. How does dsurf depend on crystallographic orientation? How does the phenomenon depend on the extent of band bending? Does persistent photoconductivity come into play? Can the effect be modified by band bending modification via surface photovoltage effects? All of the above questions pertain to epitaxial films as well, but other questions also arise. How do the film thickness and strain state affect dsurf? Can the surface conduction effect be enhanced by judicious design and growth of quantum well structures made from ZnO, MgxZn1-xO, and/or CdxZn1-xO? Answering these and other questions that arise will expand our understanding of this fascinating and potentially important material, as well as pave the way for device applications.

Chambers, Scott A.

2007-12-01T23:59:59.000Z

271

HYDROGENATION AND CRACKING OF COAL RELATED FUSED-RING STRUCTURES USING ZnCl2 AND AlCl3 CATALYSTS  

E-Print Network (OSTI)

of Molten Salt Catalysts, Ph.D. Thesis, Department ofUSING ZnC1 2 AND AlC1 3 CATALYSTS Sadie S. Salim (Ph.D.With Metal Halide Catalysts Coal Structure Literature Review

Salim, Sadie S.

2013-01-01T23:59:59.000Z

272

DOI: 10.1002/ejic.200701306 Facile Gram-Scale Growth of Single-Crystalline Nanotetrapod-Assembled ZnO  

E-Print Network (OSTI)

combustion and catalyst-free method, pure single-crystalline nanotetrapod-assembled bulk nano-ZnO was grown, Duke University, Durham, North Carolina 27708, USA [d] U.S. Army Aviation & Missile Research

Liu, Jie

273

Properties of In-Doped ZnO Films Grown by Metalorganic Chemical Vapor Deposition on GaN(0001) Templates  

E-Print Network (OSTI)

TCO is amor- phous indium tin oxide (ITO), most commonlythe properties of indium-doped zinc oxide layers grown byoxide, doping, n-type, MOCVD, metalorganic chemical vapor deposition, ZnO: In, indium

Ben-Yaacov, Tammy; Ive, Tommy; Walle, Chris G.; Mishra, Umesh K.; Speck, James S.; Denbaars, Steven P.

2010-01-01T23:59:59.000Z

274

Effect of Heating, Ion-Beam Milling, and ZnTe:Cu Deposition on the Spectroscopic Cathodoluminescence of Polycrystalline CdTe: Preprint  

DOE Green Energy (OSTI)

Presented at the 2001 NCPV Program Review Meeting: Cathodoluminescence used to study evolution of electro-optical properties of back surface of CdS/CdTe during initial steps of fabricating NREL ZnTe:Cu contact.

Gessert, T. A.; Romero, M. J.; Asher, S. E.

2001-10-01T23:59:59.000Z

275

Optical Properties of Zn(O,S) Thin Films Deposited by RF Sputtering, Atomic Layer Deposition, and Chemical Bath Deposition: Preprint  

DOE Green Energy (OSTI)

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.

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

276

Assessment of Hydrogen Solubility in the CaO-SiO2-FeOt Based ...  

Science Conference Proceedings (OSTI)

A Sintering Ore Blending Optimization Model Based on 'Iron Increase and Silicon ... on the Al2O3 Extraction Rate during Acid Leaching Process of Coal Fly Ash.

277

http://hq.na.gov/default.aspx?L=ITEM&ITEM=17500&CA=30&OT=101...  

NLE Websites -- All DOE Office Websites (Extended Search)

Advanced Simulation & Computing (ASC) Defense Nuclear Nonproliferation (NA-20) Nuclear Cities Initiative (NCI) DOE Sites DOE Callup Directory Energy.Gov Simulation in...

278

FACTS Operator Training Simulator (FACTS-OTS), Version 1.21  

Science Conference Proceedings (OSTI)

This software emulates the operation of FACTS controllers in a large power system with specialization to NYPA’s Convertible Static Compensator at the Marcy substation. The software is developed to implement a multi-functional FACTS Controller Operator Training Simulator. The Simulator uses GENESIS to display the CSC screens used by the CSC manufacturer and MATLAB to perform the dispatch computation and display station one-line diagrams similar to those used in the NYPA control center. Inputs from NYPA en...

2009-04-07T23:59:59.000Z

279

OT1: Detectors III CCDs1 March 2010 1 Optical/IR Observational Astronomy  

E-Print Network (OSTI)

rendering and smearing of images ­ Mitigate by employing "fat zero", i.e. pre-flashing to fill up those

Peletier, Reynier

280

The Fate of MAb targeted Cd125mTe/ZnS nanoparaticles in vivo  

Science Conference Proceedings (OSTI)

Nanoparticles (NP) have potential as carriers for drugs and radioisotopes. Quantitative measures of NP biodistribution in vivo are needed to determine the effectiveness of these carriers. We have used a model system of radiolabeled quantum dots to document the competition between efficient vascular targeting and interaction of the NP with the reticuloendothelial (RE) system. We have prepared (125m)Te-labeled CdTe NP that are capped with ZnS. Te-125m has a half-life and decay characteristics very similar to those for (125)I. The synthesized particles are stable in aqueous solution and are derivatized with mercaptoacetic acid and then conjugated with specific antibody. To evaluate specific targeting, we used the monoclonal antibody MAb 201B that binds to murine thrombomodulin expressed in the lumen of lung blood vessels. The MAb-targeted NP were tested for targeting performance in vivo using single-photon emission computed tomography (SPECT)/computed tomography (CT) imaging, tissue autoradiography and standard organ biodistribution techniques. Biodistribution was also determined in mice that had been depleted of phagocytic cells by use of clodronate-loaded liposomes. Cd(125m)Te/ZnS NP coupled with MAb 201B retained radioisotope and antibody activity and accumulated in lung (>400% injected dose [ID]/g) within 1 h of intravenous injection. Control antibody-coupled NP did not accumulate in lung (<10% ID/g) but accumulated in liver and spleen. Images from microSPECT/CT and autoradiography studies of the targeted NP document this specific uptake and demonstrate uniform distribution in lung with minor accumulation in liver and spleen. Within a few hours, a large fraction of lung-targeted NP redistributed to spleen and liver or was excreted. We hypothesized that NP attract phagocytic cells that engulfed and removed them from circulation. This was confirmed by comparing biodistribution of targeted NP in normal mice versus those depleted of phagocytic cells. In mice treated with clodronate liposomes, accumulation of NP in liver was reduced by fivefold, while accumulation in lung at 1 h was enhanced by approximately 50%. By 24 h, loss of the targeted NP from lung was inhibited by several-fold, while accumulation in liver and spleen remained constant. Thus, the treated mice had a much larger accumulation and retention of the NP at the target site and a decrease in dose to other organs except spleen. Nanoparticles composed of CdTe, labeled with (125m)Te and capped with ZnS, can be targeted with MAb to sites in the lumen of lung vasculature. In clodronate-treated mice, which have a temporary depletion of phagocytic cells, accumulation in liver was reduced dramatically, whereas that in spleen was not. The targeting to lung was several-fold more efficient in clodronate-treated mice due to larger initial accumulation and better retention of the MAb-targeted NP at that site. This model system indicates that targeting of NP preparations is a competition between the effectiveness of the targeting agent and the natural tendency for RE uptake of the particles. Temporary inhibition of the RE system may enhance the usefulness of NP for drug and radioisotope delivery.

Kennel, Steve J [ORNL; Woodward, Jonathan [ORNL; Rondinone, Adam Justin [ORNL; Wall, Jonathan [ORNL; Mirzadeh, Saed [ORNL

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "zn zurn ot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
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281

Molecular beam epitaxy growth of PbSe on Si (211) using a ZnTe buffer layer  

Science Conference Proceedings (OSTI)

The authors report the results of successful growth of single crystalline PbSe on Si (211) substrates with ZnTe as a buffer layer by molecular beam epitaxy. Single crystalline PbSe with (511) orientation was achieved on ZnTe/Si (211), as evidenced by RHEED patterns indicative of 2 dimensional (2D) growth, x ray diffraction rocking curves with a full width at half maximum as low as 153 arc sec and mobility as large as 1.1x10{sup 4}cm{sup 2}V{sup -1}s{sup -1} at 77 K. Cross hatch patterns were found on the PbSe(511) surface in Nomarski filtered microscope images suggesting the presence of a surface thermal strain relaxation mechanism, which was confirmed by Fourier transformed high resolution transmission electron microscope images.

Wang, X. J.; Chang, Y.; Hou, Y. B.; Becker, C. R.; Kodama, R.; Aqariden, F.; Sivananthan, S. [Microphysics Laboratory, Physics Department, University of Illinois at Chicago, Illinois 60607 (United States); Microphysics Laboratory, Physics Department, University of Illinois at Chicago, Illinois 60607 and Physics Department and Quantum Functional Semiconductor Research Center, Dongguk University 3-26, Seoul 100-715 (Korea, Republic of); Microphysics Laboratory, Physics Department, University of Illinois at Chicago, Illinois 60607 (United States); EPIR Technologies, Bolingbrook, Illinois 60440 (United States); Microphysics Laboratory, Physics Department, University of Illinois at Chicago, Illinois 60607 and EPIR Technologies, Bolingbrook, Illinois 60440 (United States)

2011-09-15T23:59:59.000Z

282

Methanol Synthesis over Cu/ZnO/Al2O3: The Active Site in Industrial Catalysis  

DOE Green Energy (OSTI)

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.

Behrens, Malte

2012-03-28T23:59:59.000Z

283

Hydrogen incorporation induced metal-semiconductor transition in ZnO:H thin films sputtered at room temperature  

Science Conference Proceedings (OSTI)

The room temperature deposited ZnO:H thin films having high conductivity of 500 Ohm-Sign {sup -1} cm{sup -1} and carrier concentration reaching 1.23 Multiplication-Sign 10{sup 20} cm{sup -3} were reactively sputter deposited on glass substrates in the presence of O{sub 2} and 5% H{sub 2} in Ar. A metal-semiconductor transition at 165 K is induced by the increasing hydrogen incorporation in the films. Hydrogen forms shallow donor complex with activation energy of {approx}10-20 meV at oxygen vacancies (V{sub O}) leading to increase in carrier concentration. Hydrogen also passivates V{sub O} and V{sub Zn} causing {approx}4 times enhancement of mobility to 25.4 cm{sup 2}/V s. These films have potential for use in transparent flexible electronics.

Singh, Anil; Chaudhary, Sujeet; Pandya, D. K. [Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016 (India)] [Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016 (India)

2013-04-29T23:59:59.000Z

284

Polarization-Induced Charge Distribution at Homogeneous Zincblende/Wurtzite Heterostructural Junctions in ZnSe Nanobelts  

DOE Green Energy (OSTI)

Homogeneous heterostructural wurtzite (WZ)/zincblende (ZB) junctions are successfully fabricated in ZnSe nanobelts. Polarity continuity across the ZB/WZ interface is demonstrated. The saw-tooth-like potential profile induced by spontaneous polarization across the WZ/ZB/WZ interfaces is identified directly at the nanoscale. The polarization-induced charge distribution across the homogeneous heterostructural interfaces is proposed as a viable alternative approach towards charge tailoring in semiconductor nanostructures.

Li, L.; Jin, L.; Wang, J.; Smith, D. J.; Yin, W. J.; Yan, Y.; Sang, H.; Choy, W. C. H.; McCartney, M. R.

2012-03-08T23:59:59.000Z

285

Band alignment of InGaZnO{sub 4}/Si interface by hard x-ray photoelectron spectroscopy  

SciTech Connect

Although amorphous InGaZnO{sub 4} has intensively been studied for a semiconductor channel material of thin-film transistors in next-generation flat-panel displays, its electronic structure parameters have not been reported. In this work, the electron affinities ({chi}) and the ionization potentials (I{sub p}) of crystalline and amorphous InGaZnO{sub 4} (c-IGZO and a-IGZO) were measured using bulk-sensitive hard x-ray photoelectron spectroscopy. First, the {chi} and I{sub p} values of c-IGZO and a-IGZO thin films were estimated by aligning the Zn 2p{sub 3/2} core level energies to a literature value for ZnO, which provided {chi} = 3.90 eV and I{sub p} = 7.58 eV for c-IGZO and 4.31 eV and 7.41 eV for a-IGZO. It was also confirmed that the escape depth of the photoelectrons excited by the photon energy of 5950.2 eV is 3.3 nm for a-IGZO and large enough for directly measuring the interface electronic structure using a-IGZO/c-Si heterojunctions. It provided the valence band offset of {approx}2.3 eV, which agrees well with the above data. The present results substantiate that the a-IGZO/c-Si interface follows well the Schottky-Mott rule.

Lee, Kyeongmi; Kamiya, Toshio [Materials and Structures Laboratory, Tokyo Institute of Technology, Mailbox R3-1, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Nomura, Kenji [Frontier Research Center, Tokyo Institute of Technology, Mailbox S2-13, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Yanagi, Hiroshi [Interdisciplinary Graduate School of Medical and Engineering Material Science and Technology, University of Yamanashi, 4-4-37 Takeda, Kofu, Yamanashi 400-8510 (Japan); Ikenaga, Eiji; Sugiyama, Takeharu [Japan Synchrotron Radiation Research Institute, SPring-8, Hyogo 679-5198 (Japan); Kobayashi, Keisuke [National Institute for Materials Science, SPring-8, Hyogo 679-5148 (Japan); Hosono, Hideo [Materials and Structures Laboratory, Tokyo Institute of Technology, Mailbox R3-1, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Frontier Research Center, Tokyo Institute of Technology, Mailbox S2-13, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan)

2012-08-01T23:59:59.000Z

286

Epitaxial Growth and Properties of Cobalt-doped ZnO on ?-Al?O? Single-Crystal Substrates  

SciTech Connect

Co-doped ZnO (CoxZn?-xO) is of potential interest for spintronics due to the prediction of room-temperature ferromagnetism. We have grown epitaxial CoxZn?-xO films on Al?O?(012) substrates by metalorganic chemical vapor deposition using a liquid precursor delivery system. High concentrations of Co (x < 0.35) can be uniformly incorporated into the film without phase segregation. Co is found to be in the ?² oxidation state, independent of x. This material can be grown n type by the deliberate incorporation of oxygen vacancies, but not by inclusion of ~1 at. % Al. Semiconducting films remain ferromagnetic up to 350 K. In contrast films without oxygen vacancies are insulating and nonmagnetic, suggesting that exchange interaction is mediated by itinerant carriers. The saturation and remanent magnetization on a per Co basis was very small (< 0.1 ?B/Co), even in the best films. The dependence of saturation magnetization, as measured by optical magnetic circular dichroism, on magnetic field and temperature, agrees with the theoretical Brillouin function, demonstrating that the majority of the Co(II) ions behave as magnetically isolated S = 3/2 spins.

Tuan, Allan C.; Bryan, John D.; Pakhomov, Alexandre; Shutthanandan, V.; Thevuthasan, Suntharampillai; McCready, David E.; Gaspar, Dan J.; Engelhard, Mark H.; Rogers, J. W.; Krishnan, Kannan M.; Gamelin, Daniel R.; Chambers, Scott A.

2004-08-30T23:59:59.000Z

287

Ga-doped ZnO grown by pulsed laser deposition in H2: the roles of Ga and H  

DOE Green Energy (OSTI)

Highly conductive thin films of ZnO doped with Ga were grown by pulsed-laser deposition (PLD) with 10 mTorr of H2 in the growth chamber. Compared with a more conventional method of producing conductive films of ZnO, i.e., growth in O2 followed by annealing in forming gas (5% H2 in Ar), the H2 method requires no post-growth anneal and also produces higher carrier concentrations and lower resistivities with better depth uniformity. As an example, a 65-nm-thick sample had a room-temperature mobility of 32 cm2/V-s, a concentration of 6.8 x 1020 cm-3, and a resistivity of 2.9 x 10^-4 ohm-cm. From a scattering model, the donor and acceptor concentrations were calculated as 8.9 x 1020 and 2.1 x 10^20 cm-3, respectively, as compared to the Ga and H concentrations of 11 x 10^20 and 1 x 10^20 cm-3. Thus, H does not play a significant role as a donor in this type of ZnO

Look, David; Droubay, Timothy; McCloy, John S.; Zhu, Zihua; Chambers, Scott A.

2011-01-11T23:59:59.000Z

288

On the Sn loss from thin films of the material system Cu-Zn-Sn-S in high vacuum  

Science Conference Proceedings (OSTI)

In this paper the Sn loss from thin films of the material system Cu-Zn-Sn-S and the subsystems Cu-Sn-S and Sn-S in high vacuum is investigated. A combination of in situ x-ray diffractometry and x-ray fluorescence (XRF) at a synchrotron light source allowed identifying phases, which tend to decompose and evaporate a Sn-containing compound. On the basis of the XRF results a quantification of the Sn loss from the films during annealing experiments is presented. It can be shown that the evaporation rate from the different phases decreases according to the order SnS{yields}Cu{sub 2}SnS{sub 3}{yields}Cu{sub 4}SnS{sub 4}{yields}Cu{sub 2}ZnSnS{sub 4}. The phase SnS is assigned as the evaporating compound. The influence of an additional inert gas component on the Sn loss and on the formation of Cu{sub 2}ZnSnS{sub 4} thin films is discussed.

Weber, A.; Mainz, R.; Schock, H. W. [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Glienicker Str. 100, D-14109 Berlin (Germany)

2010-01-15T23:59:59.000Z

289

Electronic band structures and photovoltaic properties of MWO{sub 4} (M=Zn, Mg, Ca, Sr) compounds  

Science Conference Proceedings (OSTI)

Divalent metal tungstates, MWO{sub 4}, with wolframite (M=Zn and Mg) and scheelite (M=Ca and Sr) structures were prepared using a conventional solid state reaction method. Their electronic band structures were investigated by a combination of electronic band structure calculations and electrochemical measurements. From these investigations, it was found that the band structures (i.e. band positions and band gaps) of the divalent metal tungstates were significantly influenced by their crystal structural environments, such as the W-O bond length. Their photovoltaic properties were evaluated by applying to the working electrodes for dye-sensitized solar cells. The dye-sensitized solar cells employing the wolframite-structured metal tungstates (ZnWO{sub 4} and MgWO{sub 4}) exhibited better performance than those using the scheelite-structured metal tungstates (CaWO{sub 4} and SrWO{sub 4}), which was attributed to their enhanced electron transfer resulting from their appropriate band positions. - Graphical abstract: The electronic band structures of divalent metal tungstates are described from the combination of experimental results and theoretical calculations, and their electronic structure-dependent photovoltaic performances are also studied. Highlights: > MWO{sub 4} compounds with wolframite (M=Zn and Mg) and scheelite structure (M=Ca and Sr) were prepared. > Their electronic band structures were investigated by the calculations and the measurements. > Their photovoltaic properties were determined by the crystal and electronic structures.

Kim, Dong Wook, E-mail: dong0414@snu.ac.kr [Department of Materials Science and Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Research Institute of Advanced Materials (RIAM), Seoul National University, Seoul 151-744 (Korea, Republic of); Cho, In-Sun [Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Shin, Seong Sik [Department of Materials Science and Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Lee, Sangwook [Department of Materials Science and Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Research Institute of Advanced Materials (RIAM), Seoul National University, Seoul 151-744 (Korea, Republic of); Noh, Tae Hoon; Kim, Dong Hoe [Department of Materials Science and Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Jung, Hyun Suk [School of Advanced Materials Engineering, Kookmin University, Seoul 136-702 (Korea, Republic of); Hong, Kug Sun, E-mail: kshongss@plaza.snu.ac.kr [Department of Materials Science and Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Research Institute of Advanced Materials (RIAM), Seoul National University, Seoul 151-744 (Korea, Republic of)

2011-08-15T23:59:59.000Z

290

ZnO:Al Doping Level and Hydrogen Growth Ambient Effects on CIGS Solar Cell Performance: Preprint  

DOE Green Energy (OSTI)

Cu(In,Ga)Se2 (CIGS) photovoltaic (PV) cells require a highly conducting and transparent electrode for optimum device performance. ZnO:Al films grown from targets containing 2.0 wt.% Al2O3 are commonly used for this purpose. Maximum carrier mobilities of these films grown at room temperature are ~20-25 cm2V-1s-1. Therefore, relatively high carrier concentrations are required to achieve the desired conductivity, which leads to free carrier absorption in the near infrared (IR). Lightly doped films (0.05 - 0.2 wt.% Al2O3), which show less IR absorption, reach mobility values greater than 50 cm2V-1s-1 when deposited in H2 partial pressure. We incorporate these lightly doped ZnO:Al layers into CIGS PV cells produced at the National Renewable Energy Laboratory (NREL). Preliminary results show quantum efficiency values of these cells rival those of a past world-record cell produced at NREL that used 2.0 wt.% Al-doped ZnO films. The highest cell efficiency obtained in this trial was 18.1%.

Duenow, J. N.; Gessert, T. A.; Wood, D. M.; Egaas, B.; Noufi, R.; Coutts,T. J.

2008-05-01T23:59:59.000Z

291

Band or Polaron: The Hole Conduction Mechanism in the p-Type Spinel Rh 2ZnO4  

DOE Green Energy (OSTI)

Given the emerging role of oxide spinels as hole conductors, we discuss in this article the traditional vs. new methodologies of determining the type of conduction mechanism at play - localized polaronic vs. band-like transport. Applying (i) traditional small polaron analysis to our in-situ high temperature four-point conductivity and thermopower measurements, we previously found an activated mobility, which is indicative of the small polaron mechanism. However, (ii) employing the recent developments in correcting density functional methodologies for hole localization, we predict that the self-trapped hole is unstable and that Rh{sub 2}ZnO{sub 4} is instead a band conductor with a large effective mass. The hole mobility measured by high-field room temperature Hall effect also suggests band rather than polaron conduction. The apparent contradiction between the conclusion of the traditional procedure (i) and first-principles theory (ii) is resolved by taking into account in the previous transport analysis the temperature dependence of the effective density of states, which leads to the result that the mobility is actually temperature-independent in Rh{sub 2}ZnO{sub 4}. Our case study on Rh{sub 2}ZnO{sub 4} illustrates the range of experimental and theoretical approaches at hand to determine whether the transport mechanism of a semiconductor is band or small polaron conduction.

Nagaraja, A. R.; Perry, N. H.; Mason, T. O.; Tang, Y.; Grayson, M.; Paudel, T. R.; Lany, S.; Zunger, A.

2012-01-01T23:59:59.000Z

292

Fission decay of N = Z nuclei at high angular momentum: $^{60}$Zn  

E-Print Network (OSTI)

Using a unique two-arm detector system for heavy ions (the BRS, binary reaction spectrometer) coincident fission events have been measured from the decay of $^{60}$Zn compound nuclei formed at 88MeV excitation energy in the reactions with $^{36}$Ar beams on a $^{24}$Mg target at $E_{lab}(^{36}$Ar) = 195 MeV. The detectors consisted of two large area position sensitive (x,y) gas telescopes with Bragg-ionization chambers. From the binary coincidences in the two detectors inclusive and exclusive cross sections for fission channels with differing losses of charge were obtained. Narrow out-of-plane correlations corresponding to coplanar decay are observed for two fragments emitted in binary events, and in the data for ternary decay with missing charges from 4 up to 8. After subtraction of broad components these narrow correlations are interpreted as a ternary fission process at high angular momentum through an elongated shape. The lighter mass in the neck region consists dominantly of two or three-particles. Differential cross sections for the different mass splits for binary and ternary fission are presented. The relative yields of the binary and ternary events are explained using the statistical model based on the extended Hauser-Feshbach formalism for compound nucleus decay. The ternary fission process can be described by the decay of hyper-deformed states with angular momentum around 45-52 $hbar$.

W. Von Oertzen; V. Zherebchevsky; B. Gebauer; C. Schulz; S. Thummerer; D. Kamanin; G. Royer; T. Wilpert

2008-11-03T23:59:59.000Z

293

Effects of Bulk and Surface Conductivity on the Performance of CdZnTe Pixel Detectors  

E-Print Network (OSTI)

We studied the effects of bulk and surface conductivity on the performance of high-resistivity CdZnTe (CZT) pixel detectors with Pt contacts. We emphasize the difference in mechanisms of the bulk and surface conductivity as indicated by their different temperature behaviors. In addition, the existence of a thin (10-100 A) oxide layer on the surface of CZT, formed during the fabrication process, affects both bulk and surface leakage currents. We demonstrate that the measured I-V dependencies of bulk current can be explained by considering the CZT detector as a metal-semiconductor-metal system with two back-to-back Schottky-barrier contacts. The high surface leakage current is apparently due to the presence of a low-resistivity surface layer that has characteristics which differ considerably from those of the bulk material. This surface layer has a profound effect on the charge collection efficiency in detectors with multi-contact geometry; some fraction of the electric field lines originated on the cathode int...

Bolotnikov, A E; Cook, W R; Harrison, F A; Kuvvetli, I; Schindler, S; Bolotnikov, Aleksey E.; Cook, Walter R.; Harrison, Fiona A.; Kuvvetli, Irfan; Schindler, Stephen M.

2001-01-01T23:59:59.000Z

294

Mineralogy and Geochemistry of Pb, Zn and Ag Mine Tailings Originating From Carbonate-Rich Deposits  

E-Print Network (OSTI)

Mining for silver, lead, zinc, and copper in Zimapan, Hidalgo State, Mexico has been ongoing since 1576. Unsecured tailings heaps and associated acid mine drainage have presented problems related to soil quality, water quality, and dust emission control in the Zimapan area. Objectives of the study of the mine tailings are (1) to determine mineralogy of the tailings in order to identify acid-producing minerals and heavy metals at risk for release in acidic conditions, and (2) to quantify carbonate minerals and (3) to determine heavy metal content that may be released by the products of sulfide mineral weathering. Representative mine tailings have been sampled from a site located north of Zimapan. Mineralogical characterization has been conducted with X-ray diffraction (XRD), and scanning and transmission electron microscopes (SEM and TEM). Total carbonates have been determined the Chittick procedure. X-Ray Fluorescence (XRF) has been utilized to determine total elemental composition. XRD and SEM analyses have confirmed the presence of pyrite and arsenopyrite indicating a potential for acid mine drainage. Calcite has been confirmed to have a significant presence in the unweathered samples by XRD and the Chittick procedure, with some samples containing an average of 19.4% calcite. NAA and XRF have revealed significant concentrations of toxic elements such as As, Pb and Zn in both the oxidized and unoxidized samples.

McClure, Roberta 1981-

2012-12-01T23:59:59.000Z

295

Charge transport properties in CdZnTe detectors grown by the vertical Bridgman technique  

Science Conference Proceedings (OSTI)

Presently, a great amount of effort is being devoted to the development of CdTe and CdZnTe (CZT) detectors for a large variety of applications such as medical, industrial, and space research. We present the spectroscopic properties of some CZT crystals grown by the standard vertical Bridgman method and by the boron oxide encapsulated vertical Bridgman method, which has been recently implemented at IMEM-CNR (Parma, Italy). In this technique, the crystal is grown in an open quartz crucible fully encapsulated by a thin layer of liquid boron oxide. This method prevents contact between the crystal and the crucible, thereby allowing larger single grains with a lower dislocation density to be obtained. Several mono-electrode detectors were realized, with each having two planar gold contacts. The samples are characterized by an active area of about 7 mm x 7 mm and thicknesses ranging from 1 to 2 mm. The charge transport properties of the detectors have been studied by mobility-lifetime ({mu} x {tau}) product measurements, carried out at the European Synchrotron Radiation Facility (Grenoble, France) in the planar transverse field configuration, where the impinging beam direction is orthogonal to the collecting electric field. We have performed several fine scans between the electrodes with a beam spot of 10 {mu}m x 10 {mu}m at various energies from 60 to 400 keV. In this work, we present the test results in terms of the ({mu} x {tau}) product of both charge carriers.

Auricchio, N.; Caroli, E. [INAF/IASF-Bologna, Bologna, 40129 (Italy); Marchini, L.; Zappettini, A. [IMEM-CNR, Parma, 43100 (Italy); Abbene, L. [DIFI, University of Palermo, Palermo, 90128 (Italy); Honkimaki, V. [European Synchrotron Radiation Facility, Grenoble, 38000 (France)

2011-12-15T23:59:59.000Z

296

Optimization of a parallel hole collimator/CdZnTe gamma-camera architecture for scintimammography  

Science Conference Proceedings (OSTI)

Purpose: Small field-of-view CdZnTe (CZT) gamma cameras are increasingly studied for breast lesion detection to complement mammography or ultrasonographic findings. However, in classical collimation configurations, they remain limited by the trade-off between spatial resolution and sensitivity. The HiSens architecture was proposed to overcome these limitations. Using an accurate 3D localization of the interactions inside the detector, this architecture leads to a gain in sensitivity without loss in spatial resolution. In this article, the relevance of the HiSens architecture for planar scintimammography is studied. Methods: A detective quantum efficiency (DQE) computation method is developed and used to optimize the dimensioning of a parallel hole collimator dedicated to scintimammography. Based on the DQE curves, the impact of the collimator-to-detector distance is studied. Two algorithms are proposed to combine data acquired with different collimator-to-detector distances. Results: It is shown that CZT detector virtual pixelization increases system sensitivity by 3.3 while preserving a standard LEHR spatial resolution. The introduction of a gap between the CZT detector and the collimator is useful to modulate the DQE curve shape. The combination of data acquired using different gaps in the image formation process leads to enhanced restoration of the frequency content of the images, resulting in image contrast and spatial resolution improvements. Conclusions: Acquisition duration or injected activity could be markedly reduced if the HiSens architecture with an appropriate collimator-detector gap were used.

Robert, Charlotte; Montemont, Guillaume; Rebuffel, Veronique; Verger, Loieck; Buvat, Irene [CEA-LETI-MINATEC, F38054 Grenoble (France); IMNC-UMR 8165 CNRS, Universites Paris 7 et 11, Batiment 440, 91406 Orsay (France)

2011-04-15T23:59:59.000Z

297

X-ray Topography to Characterize Surface Damage on CdZnTe Crystals  

Science Conference Proceedings (OSTI)

Synthetic CdZnTe or 'CZT' crystals can be used for room temperature detection of {gamma}-radiation. Structural/morphological heterogeneities within CZT, such as twinning, secondary phases (often referred to as inclusions or precipitates), and poly-crystallinity can affect detector performance. As part of a broader study using synchrotron radiation techniques to correlate detector performance to microstructure, x-ray topography (XRT) has been used to characterize CZT crystals. We have found that CZT crystals almost always have a variety of residual surface damage, which interferes with our ability to observe the underlying microstructure for purposes of crystal quality evaluation. Specific structures are identifiable as resulting from fabrication processes and from handling and shipping of sample crystals. Etching was found to remove this damage; however, our studies have shown that the radiation detector performance of the etched surfaces was inferior to the as-polished surface due to higher surface currents which result in more peak tailing and less energy resolution. We have not fully investigated the effects of the various types of inducible damage on radiation detector performance. (authors)

Black, David; Woicik, Joseph [NIST, Gaithersburg, Maryland (United States); Duff, Martine C.; Hunter, Douglas B. [SRNL, Aiken, South Carolina (United States); Burger, Arnold; Groza, Michael [Fisk University, Nashville, Tennessee (United States)

2008-07-01T23:59:59.000Z

298

Effects of Te inclusions on the performance of CdZnTe radiation detectors  

Science Conference Proceedings (OSTI)

Te inclusions existing at high concentrations in CdZnTe (CZT) material can degrade the performance of CZT detectors. These microscopic defects trap the free electrons generated by incident radiation, so entailing significant fluctuations in the total collected charge and thereby strongly affecting the energy resolution of thick (long-drift) detectors. Such effects were demonstrated in thin planar detectors, and, in many cases, they proved to be the dominant cause of the low performance of thick detectors, wherein the fluctuations in the charge losses accumulate along the charge's drift path. We continued studying this effect using different tools and techniques. We employed a dedicated beamline recently established at BNL's National Synchrotron Light Source for characterizing semiconductor radiation detectors, along with an IR transmission microscope system, the combination of which allowed us to correlate the concentration of defects with the devices performances. We present here our new results from testing over 50 CZT samples grown by different techniques. Our goals are to establish tolerable limits on the size and concentrations of these detrimental Te inclusions in CZT material, and to provide feedback to crystal growers to reduce their numbers in the material.

Bolotnikov,A.E.; Abdul-Jabber, N. M.; Babalola, O. S.; Camarda, G. S.; Cui, Y.; Hossain, A. M.; Jackson, E. M.; Jackson, H. C.; James, J. A.; Kohman, K. T.; Luryi, A. L.; James, R. B.

2008-10-19T23:59:59.000Z

299

X-ray Topography to Characterize Surface Damage on CdZnTe Crystals  

Science Conference Proceedings (OSTI)

Synthetic CdZnTe or 'CZT' crystals can be used for room temperature detection of {gamma}-radiation. Structural/morphological heterogeneities within CZT, such as twinning, secondary phases (often referred to as inclusions or precipitates), and poly-crystallinity can affect detector performance. As part of a broader study using synchrotron radiation techniques to correlate detector performance to microstructure, x-ray topography (XRT) has been used to characterize CZT crystals. We have found that CZT crystals almost always have a variety of residual surface damage, which interferes with our ability to observe the underlying microstructure for purposes of crystal quality evaluation. Specific structures are identifiable as resulting from fabrication processes and from handling and shipping of sample crystals. Etching was found to remove this damage; however, our studies have shown that the radiation detector performance of the etched surfaces was inferior to the as-polished surface due to higher surface currents which result in more peak tailing and less energy resolution. We have not fully investigated the effects of the various types of inducible damage on radiation detector performance.

Black, David; Woicik, Joseph; Duff, Martine C.; Hunter, Douglas B.; Burger, Arnold; Groza, Michael (SRNL); (SBU); (NIST); (Fisk U)

2008-12-05T23:59:59.000Z

300

Two Homologous Intermetallic Phases in the Na-Au-Zn System with Sodium Bound in Unusual Paired Sites within 1D Tunnels  

SciTech Connect

The Na-Au-Zn system contains the two intermetallic phases Na(0.97(4))Au(2)Zn(4)(I) and Na(0.72(4))Au(2)Zn(2)(II) that are commensurately and incommensurately modulated derivatives of K(0.37)Cd(2), respectively. Compound I crystallizes in tetragonal space group P4/mbm (No. 127), a = 7.986(1) Å, c = 7.971(1) Å, Z = 4, as a 1 × 1 × 3 superstructure derivative of K(0.37)Cd(2)(I4/mcm). Compound II is a weakly incommensurate derivative of K(0.37)Cd(2) with a modulation vector q = 0.189(1) along c. Its structure was solved in superspace group P4/mbm(00g)00ss, a = 7.8799(6) Å, c = 2.7326(4) Å, Z = 2, as well as its average structure in P4/mbm with the same lattice parameters.. The Au-Zn networks in both consist of layers of gold or zinc squares that are condensed antiprismatically along c ([Au(4/2)Zn(4)Zn(4)Au(4/2)] for I and [Au(4/2)Zn(4)Au(4/2)] for II) to define fairly uniform tunnels. The long-range cation dispositions in the tunnels are all clearly and rationally defined by electron density (Fourier) mapping. These show only close, somewhat diffuse, pairs of opposed, ?50% occupied Na sites that are centered on (I)(shown) or between (II) the gold squares. Tight-binding electronic structure calculations via linear muffin-tin-orbital (LMTO) methods, assuming random occupancy of ? ?100% of nonpaired Na sites, again show that the major Hamilton bonding populations in both compounds arise from the polar heteroatomic Au-Zn interactions. Clear Na-Au (and lesser Na-Zn) bonding is also evident in the COHP functions. These two compounds are the only stable ternary phases in the (Cs,Rb,K,Na)-Au-Zn systems, emphasizing the special bonding and packing requirements in these sodium structures

Samal, Saroj L.; Lin, Qisheng; Corbett, John D.

2012-08-20T23:59:59.000Z

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301

Structure Determination of Two Modulated g-Brass Structures in the Zn-Pd System through a (3+1)-Dimensional Space Description  

Science Conference Proceedings (OSTI)

The structure determination of two composite compounds in the Zn-Pd system with close relationships to the cubic g-brass structure Zn11-dPd2+d is reported. Their structures have been solved from single crystal X-ray diffraction data within a (3 + 1)-dimensional [(3 + 1)D] formalism. Zn75.7(7)Pd24.3 and Zn78.8(7)Pd21.2 crystallize with orthorhombic symmetry, super space group Xmmm(00g)0s0 X=[(1/2,1/2,0,0);(0,1/2,1/2,1/2); (1/2,0,1/2,1/2)], with the following lattice parameters, respectively: as = 12.929(3) , bs = 9.112(4) , cs = 2.5631(7) , q = 8/13 c* and Vs = 302.1(3) A3 and as = 12.909(3) , bs = 9.115(3) , cs = 2.6052(6) , q = 11/18 c* and Vs = 306.4(2) A3. Their structures may be considered as commensurate because they can be refined in the conventional 3D space groups (Cmcm and Cmce, respectively) using super cells, but they also refined within the (3 + 1)D formalism to residual factors R = 3.22% for 139 parameters and 1184 independent reflections for Zn75.7(7)Pd24.3 and R = 3.46% for 197 parameters and 1804 independent reflections for Zn78.8(7)Pd21.2. The use of the (3 + 1)D formalism improves the results of the refinement and leads to a better understanding of the complexity of the atomic arrangement through the various modulations (occupation waves and displacive waves). Our refinements emphasize a unique Pd/Zn occupation modulation at the center of the icosahedra which is correlated with the distortion of the sites.

Gourdon, Olivier [ORNL; Izaola, Zunbeltz [Hahn-Meitner Institut, Berlin, Germany; Elcoro, Luis [University of Pais Vasco; Petricek, Vaclav [Institute of Physics, Czech Republic; Miller, Gordon J. [Iowa State University

2009-01-01T23:59:59.000Z

302

Solvothermal synthesis of Zn{sub 2}GeO{sub 4}:Mn{sup 2+} nanophosphor in water/diethylene glycol system  

SciTech Connect

The influence of aging of the suspension containing the amorphous precusors on structural, compositional and photoluminescent properties is studied to understand the mechanism on the formation of Zn{sub 2}GeO{sub 4}:Mn{sup 2+} nanoparticles during the solvothermal reaction in the water/diethylene glycol mixed solvent. Aging at 200 Degree-Sign C for 20 min forms the crystalline Zn{sub 2}GeO{sub 4} nanorods and then they grow up to {approx} 50 nm in mean length after aging for 240 min. Their interplanar spacing of (410) increases with increasing the aging time. The photoluminescence intensity corresponding to the d-d transition of Mn{sup 2+} increases with increasing the aging time up to 120 min, and then decreases after aging for 240 min. The photoluminescence lifetime decreases with increasing the aging time, indicating the locally concentrated Mn{sup 2+} ions. These results reveal that Mn{sup 2+} ions gradually replace Zn{sup 2+} ions near surface through repeating dissolusion and precipitation processes during prolonged aging after the complete crystallization of Zn{sub 2}GeO{sub 4}. - Graphical abstract: TEM images of Zn{sub 2}GeO{sub 4}:Mn{sup 2+} nanoparticles aged at 200 Degree-Sign C for different aging times in the mixed solvent of water and diethylene glycol. Highlights: Black-Right-Pointing-Pointer Mechanism on formation of Zn{sub 2}GeO{sub 4}:Mn{sup 2+} nanophosphor under solvothermal condition. Black-Right-Pointing-Pointer Zn{sub 2}GeO{sub 4} nanorods crystallize via amorphous precursors. Black-Right-Pointing-Pointer Gradual substitution of Mn{sup 2+} during prolonged aging. Black-Right-Pointing-Pointer Such an inhomogeneous Mn{sup 2+} doping process results in concentration quenching.

Takeshita, Satoru; Honda, Joji [Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); Isobe, Tetsuhiko, E-mail: isobe@applc.keio.ac.jp [Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); Sawayama, Tomohiro; Niikura, Seiji [SINLOIHI Company, Limited, 2-19-12 Dai, Kamakura 247-8550 (Japan)

2012-05-15T23:59:59.000Z

303

Synthesis and characterization of 5-fluorocytosine intercalated Zn-Al layered double hydroxide  

Science Conference Proceedings (OSTI)

In this paper, the intercalation of 5-fluorocytosine (5-FC) into a layered inorganic host, Zn-Al layered double hydroxide (LDH), has been carried out using coprecipitation method to obtain 5-FC/LDH nanohybrids. The intercalated amount (A{sub In}) of 5-FC into the LDH is remarkably dependent on the molar ratio (R{sub F/M}) of 5-FC to metal ions and the pH of coprecipitation system. The morphology of 5-FC molecules in 5-FC/LDH nanohybrids is dependent on the A{sub In}. It is interestingly found that the morphology of the nanohybrid particles may be changed with the increase of R{sub F/M} from hexagonal plate particles to threadlike particles. The in vitro drug release from the nanohybrids is remarkably lower than that from the corresponding physical mixture and pristine 5-FC at either pH 4.8 or pH 7.5. In addition, the release rate of 5-FC from the nanohybrid at pH 7.5 is remarkably lower than that at pH 4.8, this is due to a possible difference in the release mechanism. The obtained results show these drug-inorganic nanohybrids can be used as a potential drug delivery system. - Graphical abstract: The 5-fluorocytosine (5-FC) has been intercalated into layered double hydroxide using coprecipitation method. The morphology of 5-FC molecules in obtained nanohybrids was dependent on the intercalated amount of 5-FC. The in vitro drug release from the nanohybrids was remarkably lower than that from the corresponding physical mixture, which shows these drug-inorganic nanohybrids can be used as a potential drug delivery system.

Liu Chunxia [Key Laboratory for Colloid and Interface Chemistry of Education Ministry, Shandong University, Jinan 250100 (China); Hou Wanguo [Key Laboratory for Colloid and Interface Chemistry of Education Ministry, Shandong University, Jinan 250100 (China); College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China)], E-mail: wghou@sdu.edu.cn; Li Lifang [College of Chemistry and Material Science, Shandong Agriculture University, Taian 271018 (China); Li Yan; Liu Shaojie [Key Laboratory for Colloid and Interface Chemistry of Education Ministry, Shandong University, Jinan 250100 (China)

2008-08-15T23:59:59.000Z

304

Rapid microwave hydrothermal synthesis of ZnGa{sub 2}O{sub 4} with high photocatalytic activity toward aromatic compounds in air and dyes in liquid water  

Science Conference Proceedings (OSTI)

ZnGa{sub 2}O{sub 4} was synthesized from Ga(NO{sub 3}){sub 3} and ZnCl{sub 2} via a rapid and facile microwave-assisted hydrothermal method. The photocatalytic properties of the as-prepared ZnGa{sub 2}O{sub 4} were evaluated by the degradation of pollutants in air and aqueous solution under ultraviolet (UV) light illumination. The results demonstrated that ZnGa{sub 2}O{sub 4} had exhibited efficient photocatalytic activities higher than that of commercial P25 (Degussa Co.) in the degradation of benzene, toluene, and ethylbenzene, respectively. In the liquid phase degradation of dyes (methyl orange, Rhodamine B, and methylene blue), ZnGa{sub 2}O{sub 4} has also exhibited remarkable activities higher than that of P25. After 32 min of UV light irradiation, the decomposition ratio of methyl orange (10 ppm, 150 mL) over ZnGa{sub 2}O{sub 4} (0.06 g) was up to 99%. The TOC tests revealed that the mineralization ratio of MO (10 ppm, 150 mL) was 88.1% after 90 min of reaction. A possible mechanism of the photocatalysis over ZnGa{sub 2}O{sub 4} was also proposed. - Graphical abstract: In the degradation of RhB under UV light irradiation, ZnGa{sub 2}O{sub 4} had exhibited efficient photo-activity, and after only 24 min of irradiation the decomposition ratio was up to 99.8%. Highlights: Black-Right-Pointing-Pointer A rapid and facile M-H method to synthesize ZnGa{sub 2}O{sub 4} photocatalyst. Black-Right-Pointing-Pointer The photocatalyst exhibits high activity toward benzene and dyes. Black-Right-Pointing-Pointer The catalyst possesses more surface hydroxyl sites than TiO{sub 2} (P25). Black-Right-Pointing-Pointer Deep oxidation of different aromatic compounds and dyes over catalyst.

Sun Meng [School of Resources and Environment, University of Jinan, Jinan 250022 (China); Research Institute of Photocatalysis, State Key Laboratory Breeding Base of Photocatalysis, Fuzhou University, Fuzhou 350002 (China); Li Danzhen, E-mail: dzli@fzu.edu.cn [Research Institute of Photocatalysis, State Key Laboratory Breeding Base of Photocatalysis, Fuzhou University, Fuzhou 350002 (China); Zhang Wenjuan; Chen Zhixin; Huang Hanjie; Li Wenjuan; He Yunhui; Fu Xianzhi [Research Institute of Photocatalysis, State Key Laboratory Breeding Base of Photocatalysis, Fuzhou University, Fuzhou 350002 (China)

2012-06-15T23:59:59.000Z

305

Nitrogen [N]-incorporated ZnO piezoelectric thin films and their application for ultra-small film bulk acoustic wave resonator device fabrication  

Science Conference Proceedings (OSTI)

Nitrogen [N]-incorporated ZnO films with columnar grains of a preferred c-axis orientation were deposited on p-Si (100) wafers, using an RF magnetron sputter deposition technique. For the N incorporation into the ZnO films, an N{sub 2}O gas was used as a doping source and also various process conditions such as N{sub 2}O gas fraction and RF power were applied. Besides, some of the ZnO films were treated with the post annealing process. And then, the micro-structural characteristics of the N-incorporated ZnO films were investigated by a scanning electron microscope, an X-ray diffractometer, and an atomic force microscope techniques. Finally, employing the N-incorporated ZnO films, the solidly mounted resonator-type film bulk acoustic wave resonator devices were fabricated and their resonance characteristics were extracted. As a result, an excellent return loss (S{sub 11}) of- 63 dB was observed at{approx} 0.6 GHz, better than ever reported.

Lee, Eunju; Zhang Ruirui; Yoon, Giwan [Department of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 373-1 Guseong-dong, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of)

2011-10-01T23:59:59.000Z

306

Investigation of polycrystalline thin-film CuInSe{sub 2} solar cells based on ZnSe windows. Annual subcontract report, 15 Febraury 1992--14 February 1993  

DOE Green Energy (OSTI)

Investigations of ZnSe/CIS solar cells are being carried out in an effort to improve the efficiencies CIS cells and to determine if ZnSe is a viable alternative to CdS as a window material. MOCVD growth of ZnSe is accomplished in a SPIRE 500XT reactor housed in the Electronic Materials Laboratory at WSU Tri-Cities by reacting a zinc adduct with H{sub 2}Se. Conductive n-type ZnSe is grown by using iodine as a dopant. Ethyliodide was mixed with helium and installed on one of the gas lines to the system. ZnSe films have been grown on CIS substrates at 200{degrees}C to 250{degrees}C. ZnO is also being deposited by MOCVD by reacting tetrahydrofuran (THF) with a zinc adduct. ZnSe/CIS heterojunctions have been studied by growing n-ZnSe films onto 2 cm x 2 cm CIS substrates diced from materials supplied by Siemens and then depositing an array of aluminum circular areas 2.8.mm in diameter on top of the ZnSe to serve as contacts. Al films are deposited with a thickness of 80 to l00 {angstrom}so that light can pass through the film, thus allowing the illuminated characteristics of the ZnSe/CIS junction to be tested. Accounting for the 20 to 25 % transmittance through the Al film into the ZnSe/CIS structure, current devices have estimated, active-area AM1.5 efficiencies of 14 %. Open circuit voltages > 500 mV are often attained.

Olsen, L C [Washington State Univ. at Tri-Cities, Richland, WA (United States)

1994-05-01T23:59:59.000Z

307

Phase transformations in the Zn-Al eutectoid alloy after quenching from the high temperature triclinic beta phase  

Science Conference Proceedings (OSTI)

Ribbons of the Zn-Al eutectoid alloy obtained by melt-spinning, were heat treated at 350 deg. C during 30 min in a free atmosphere furnace, and then quenched in liquid nitrogen. The temperature correspond to {beta} phase zone, which has a triclinic crystalline structure [1, 2]. Some evidence, obtained by X-ray diffraction, show that the structures present in the just quenched material are both close-packed hexagonal ({eta}-phase) and rhombohedral (R-phase). X-ray diffractograms taken in the same ribbons after annealed 500 h at room temperature, show that the R phase its transform to {alpha} and {eta} phases.

Sandoval-Jimenez, A., E-mail: asandovalj@correo.unam.mx [Instituto Nacional de Investigaciones Nucleares, Dpto. de Aceleradores, Carretera Mexico-Toluca S/N, La Marquesa, Ocoyoacac, Mexico, C.P. 52750, ESIME, Unidad Culhuacan, Dpto. Ing. Mecanica, IPN (Mexico); Negrete, J. [Instituto de Metalurgia, Universidad Autonoma de San Luis Potosi, SLP 78210 (Mexico); Torres-Villasenor, G. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Apdo. Postal 70-360, Mexico D.F. 04510 (Mexico)

2010-11-15T23:59:59.000Z

308

Conversion of the trace elements Zn, Cd, and Pb in the combustion of near-Moscow coals  

SciTech Connect

A model for the conversion of trace elements in the combustion of near-Moscow coals based on a complex approach combining the capabilities of geochemistry, chemical thermodynamics, phase analysis, and chemical kinetics is proposed. The conversion of the trace elements Zn, Cd, and Pb as the constituents of near-Moscow coal in the flow of coal combustion products along the line of the P-59 boiler at the Ryazanskaya Thermal Power Plant was calculated. Experimental data were used in the development of the model and in calculations.

E.V. Samuilov; L.N. Lebedeva; L.S. Pokrovskaya; M.V. Faminskaya [OAO Power Engineering Institute, Moscow (Russia)

2008-10-15T23:59:59.000Z

309

Self-assembled formation and transformation of In/CdZnTe(110) nano-rings into camel-humps  

Science Conference Proceedings (OSTI)

We used in situ scanning tunneling microscopy to monitor in real time the formation of nano-rings at the molecular beam epitaxially grown In/CdZnTe(110) surface, and Auger electron spectroscopy to explore the corresponding compositional changes. In-diffusion of In and segregation of Cd to the surface in course of annealing lead to a formation of elliptically distorted nano-rings, elongated along the fast [110] diffusion direction. Exacerbated diffusion anisotropy in the liquid state, at temperatures above the melting point of In, further distorts the nano-rings into a camel-hump shape.

Cohen-Taguri, G. [School of Mechanical Engineering and Materials and Nanotechnologies Program, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978 (Israel); Ruzin, A. [School of Electrical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978 (Israel); Goldfarb, I. [School of Mechanical Engineering and Materials and Nanotechnologies Program, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978 (Israel); Research Center for Nanoscience and Nanotechnology, Tel Aviv University, Tel Aviv 69978 (Israel)

2012-05-21T23:59:59.000Z

310

Surface Enhanced Raman Spectroscopy of Pyridine on CdSe/ZnBeSe Quantum Dots Grown by MBE  

SciTech Connect

Using Surface Enhanced Raman Spectroscopy (SERS), we observed Raman enhancements (104-105) for pyridine molecules adsorbed on a II-VI semiconductor CdSe/ZnBeSe sample of uncapped self-assembled quantum dots produced by molecular beam epitaxy. When a monolayer of pyridine is adsorbed on these structures, excitation at 488 nm produces intense Raman spectra a very large enhancement of the a1, b1 and b2 modes. This indicates the presence of charge-transfer as a contributor to the enhacement.

Livingstone, Richard [City College of New York, New York, NY (United States)

2010-08-06T23:59:59.000Z

311

Formation of core/shell-like ZnSe1?xTex nanocrystals due to equilibrium surface segregation  

Science Conference Proceedings (OSTI)

We report results of equilibrium surface segregation in ZnSe{sub 1?x}Te{sub x} nanocrystals based on a computational analysis of coupled compositional, structural, and volume relaxation of the nanocrystals that employs Monte Carlo and conjugate-gradient methods according to a first-principles-parameterized description of interatomic interactions. We have determined the equilibrium concentration distribution as a function of nanocrystal size and composition for nanocrystal morphologies that include faceted equilibrium crystal shapes. The results identify the nanoparticle size and composition ranges that allow for self-assembly of core/shell-like nanocrystal structures characterized by a Te-deficient core and a Te-rich shell.

Pandey, Sumeet C.; Mountziaris, T. J.; Venkataraman, Dhandapani; Maroudas, Dimitris

2010-01-01T23:59:59.000Z

312

Detector Performance of Ammonium-Sulfide-Passivated CdZnTe and CdMnTe Materials  

Science Conference Proceedings (OSTI)

Dark currents, including those in the surface and bulk, are the leading source of electronic noise in X-ray and gamma detectors, and are responsible for degrading a detector's energy resolution. The detector material itself determines the bulk leakage current; however, the surface leakage current is controllable by depositing appropriate passivation layers. In previous research, we demonstrated the effectiveness of surface passivation in CZT (CdZnTe) and CMT (CdMnTe) materials using ammonium sulfide and ammonium fluoride. In this research, we measured the effect of such passivation on the surface states of these materials, and on the performances of detectors made from them.

Kim, K.H.; Bolotnikov, A.E.; Camarda, G.S.; Marchini, L.; Yang, G.; Hossain, A.; Cui, Y.; Xu, L.; and James, R.B.

2010-08-01T23:59:59.000Z

313

Carrier dynamics and activation energy of CdTe quantum dots in a Cd{sub x}Zn{sub 1-x}Te quantum well  

SciTech Connect

We investigate the optical properties of CdTe quantum dots (QDs) in a Cd{sub 0.3}Zn{sub 0.7}Te quantum well (QW) grown on GaAs (100) substrates. Carrier dynamics of CdTe/ZnTe QDs and quantum dots-in-a-well (DWELL) structure is studied using time-resolved photoluminescence (PL) measurements, which show the longer exciton lifetime of the DWELL structure. The activation energy of the electrons confined in the DWELL structure, as obtained from the temperature-dependent PL spectra, was also higher than that of electrons confined in the CdTe/ZnTe QDs. This behavior is attributed to the better capture of carriers into QDs within the surrounding QW.

Han, W. I.; Lee, J. H.; Yu, J. S.; Choi, J. C. [Department of Physics, Yonsei University, Wonju 220-710 (Korea, Republic of); Lee, H. S. [Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of)

2011-12-05T23:59:59.000Z

314

Development of ZnTe:Cu Contacts for CdTe Solar Cells: Cooperative Research and Development Final Report, CRADA Number CRD-08-320  

DOE Green Energy (OSTI)

The main focus of the work at NREL was on the development of Cu-doped ZnTe contacts to CdTe solar cells in the substrate configuration. The work performed under the CRADA utilized the substrate device structure used at NREL previously. All fabrication was performed at NREL. We worked on the development of Cu-doped ZnTe as well as variety of other contacts such as Sb-doped ZnTe, CuxTe, and MoSe2. We were able to optimize the contacts to improve device parameters. The improvement was obtained primarily through increasing the open-circuit voltage, to values as high as 760 mV, leading to device efficiencies of 7%.

Dhere, R.

2012-04-01T23:59:59.000Z

315

Ne{sup +} ion sputtering effect on amorphous Ga-In-Zn-O thin-film surface investigated by high-resolution XPS  

Science Conference Proceedings (OSTI)

The effect of Ne{sup +} ion sputtering on amorphous Ga-In-Zn-O (a-GIZO) thin films was investigated by using surface-sensitive, synchrotron-radiation-based, high-resolution X-ray photoelectron spectroscopy (XPS). a-GIZO thin films having different compositions (Ga{sub 2}O{sub 3}:In{sub 2}O{sub 3}:ZnO = 1:1:1, 2:2:1, 3:2:1, 4:2:1) were investigated. It was found out that the amounts of the In and Zn contents relative to that of Ga decreased noticeably after sufficient sputtering, and that there occurred a subgap state above the valence band maximum and metallic states at the In 3d and 4d core levels as well as at the Fermi edge.

Kang, Se-Jun; Lee, Mi Ji [Department of Physics, POSTECH, Pohang 790-784 (Korea, Republic of); Baik, Jae Yoon; Kim, Hyeong-Do; Thakur, Anup [Pohang Accelerator Laboratory, POSTECH, Pohang 790-784 (Korea, Republic of); Shin, Hyun-Joon [Department of Physics, POSTECH, Pohang 790-784 (Korea, Republic of); Pohang Accelerator Laboratory, POSTECH, Pohang 790-784 (Korea, Republic of); Chung, JaeGwan; Lee, Eunha; Lee, Jaecheol; Lee, JaeHak [A E Group, Samsung Advanced Institute of Technology, Yongin-si 440-712 (Korea, Republic of)

2011-12-23T23:59:59.000Z

316

Measurement of the valence band-offset in a PbSe/ZnO heterojunction by x-ray photoelectron spectroscopy  

SciTech Connect

A heterojunction of PbSe/ZnO has been grown by molecular beam epitaxy. X-ray photoelectron spectroscopy was used to directly measure the valence-band offset (VBO) of the heterojunction. The VBO, {Delta}E{sub V}, was determined as 2.51 {+-} 0.05 eV using the Pb 4p{sup 3/2} and Zn 2p{sup 3/2} core levels as a reference. The conduction-band offset, {Delta}E{sub C}, was, therefore, determined to be 0.59 {+-} 0.05 eV based on the above {Delta}E{sub V} value. This analysis indicates that the PbSe/ZnO heterojunction forms a type I (Straddling Gap) heterostructure.

Li Lin; Qiu Jijun; Weng Binbin; Yuan Zijian; Shi Zhisheng [School of Electrical and Computer Engineering, University of Oklahoma, Norman, Oklahoma 73019 (United States); Li Xiaomin; Gan Xiaoyan [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Sellers, Ian R. [Deparment of Physics, University of Oklahoma, Norman, Oklahoma 73019 (United States)

2012-12-24T23:59:59.000Z

317

Some Considerations On Photocurrent Characteristics Of Poly(alkylthiophene) And Photovoltaic Characteristics Of Poly(alkylthiophene)/ZnO Based Hybrid Solar Cells  

Science Conference Proceedings (OSTI)

Photocurrent characteristics of poly(alkylthiophene) has been investigated in ITO/poly(alkylthiophene)/Au structure by performing the V-I measurement at various light illumination intensity. The dependence of photocurrent on light intensity was clearly observed in reverse bias condition. The photocurrent characteristics obey a power law dependence on light intensity, which may be related with the electric field dependent charge carrier generation and transport. Photovoltaic characteristics has been investigated in ITO/Al-doped ZnO/poly(alkylthiophene)/Ag structure. The observed photovoltaic characteristics show the function of this ZnO layer as the acceptor layer. However, the V-I curve indicates unusual behavior indicating Ohmic-like characteristic, which is discussed by considering the nano-morphology and the conductivity properties of the ZnO layer.

Hidayat, Rahmat; Aprilia, Annisa; Bahar, Herman [Magnetic and Photonic Research Division, Jalan Ganesa 10, Bandung 40132 (Indonesia); Prijamboedi, Bambang [Inorganic and Physical Chemistry Research Division, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Jalan Ganesa 10, Bandung 40132 (Indonesia)

2010-12-23T23:59:59.000Z

318

COMPACT CdZnTe-BASED GAMMA CAMERA FOR PROSTATE CANCER IMAGING  

SciTech Connect

In this paper, we discuss the design of a compact gamma camera for high-resolution prostate cancer imaging using Cadmium Zinc Telluride (CdZnTe or CZT) radiation detectors. Prostate cancer is a common disease in men. Nowadays, a blood test measuring the level of prostate specific antigen (PSA) is widely used for screening for the disease in males over 50, followed by (ultrasound) imaging-guided biopsy. However, PSA tests have a high false-positive rate and ultrasound-guided biopsy has a high likelihood of missing small cancerous tissues. Commercial methods of nuclear medical imaging, e.g. PET and SPECT, can functionally image the organs, and potentially find cancer tissues at early stages, but their applications in diagnosing prostate cancer has been limited by the smallness of the prostate gland and the long working distance between the organ and the detectors comprising these imaging systems. CZT is a semiconductor material with wide band-gap and relatively high electron mobility, and thus can operate at room temperature without additional cooling. CZT detectors are photon-electron direct-conversion devices, thus offering high energy-resolution in detecting gamma rays, enabling energy-resolved imaging, and reducing the background of Compton-scattering events. In addition, CZT material has high stopping power for gamma rays; for medical imaging, a few-mm-thick CZT material provides adequate detection efficiency for many SPECT radiotracers. Because of these advantages, CZT detectors are becoming popular for several SPECT medical-imaging applications. Most recently, we designed a compact gamma camera using CZT detectors coupled to an application-specific-integrated-circuit (ASIC). This camera functions as a trans-rectal probe to image the prostate gland from a distance of only 1-5 cm, thus offering higher detection efficiency and higher spatial resolution. Hence, it potentially can detect prostate cancers at their early stages. The performance tests of this camera have been completed. The results show better than 6-mm resolution at a distance of 1 cm. Details of the test results are discussed in this paper.

CUI, Y.; LALL, T.; TSUI, B.; YU, J.; MAHLER, G.; BOLOTNIKOV, A.; VASKA, P.; DeGERONIMO, G.; O' CONNOR, P.; MEINKEN, G.; JOYAL, J.; BARRETT, J.; CAMARDA, G.; HOSSAIN, A.; KIM, K.H.; YANG, G.; POMPER, M.; CHO, S.; WEISMAN, K.; SEO, Y.; BABICH, J.; LaFRANCE, N.; AND JAMES, R.B.

2011-10-23T23:59:59.000Z

319

Strong room-temperature ferromagnetism of high-quality lightly Mn-doped ZnO grown by molecular beam epitaxy  

Science Conference Proceedings (OSTI)

Strong room-temperature ferromagnetism is demonstrated in single crystalline Mn-doped ZnO grown by molecular beam epitaxy. With a low Mn concentration of 2 Multiplication-Sign 10{sup 19} cm{sup -3}, Mn-doped ZnO films exhibited room-temperature ferromagnetism with a coercivity field larger than 200 Oe, a large saturation moment of 6 {mu}{sub B}/ion, and a large residue moment that is {approx}70% of the saturation magnetization. Isolated ions with long range carrier mediated spin-spin coupling may be responsible for the intrinsic ferromagnetism.

Zuo Zheng; Zhou Huimei; Olmedo, Mario J.; Kong Jieying; Liu Jianlin [Quantum Structures Laboratory, Department of Electrical Engineering, University of California - Riverside, Riverside, California 92521 (United States); Beyermann, Ward P. [Department of Physics and Astronomy, University of California - Riverside, Riverside, California 92521 (United States); Zheng Jianguo [Laboratory for Electron and X-ray Instrumentation, California Institute for Telecommunications and Information Technology, University of California - Irvine, Irvine, California 92697 (United States); Xin Yan [NHMFL, Florida State University, 1800 E. Paul Dirac Dr., Tallahassee, Florida 32310-3706 (United States)

2012-09-01T23:59:59.000Z

320

Biodistribution of radioactive Cd125mTe/ZnS nanoparticles targeted with antibody to murine lung endothelium.  

Science Conference Proceedings (OSTI)

Radioactive cadmium telluride/zinc sulfide (Cd{sup 125m}Te/ZnS) nanoparticles were targeted to mouse lung with antibody to mouse lung endothelium and quantified using radiological histology in order to test the in vivo targeting efficacy of a nanoparticle-antibody (NP-mAb) system. The nanoparticles were linked to either a monoclonal antibody to mouse lung thrombomodulin (mAb 201B) or a control antibody (mAb 33), and injected into groups of 6-week-old Balb/C female mice. Animals were sacrificed at 1, 4, 24, 72 and 144 h post-injection, and biodistribution in major organs was determined. Full body microSPECT/CT imaging was performed on a pair of mice (experimental and control) providing visual confirmation of the biodistribution. The Cd{sup 125m}Te/ZnS NPs conjugated to mAb 201B principally target the lungs while the nanoparticles coupled to mAb 33 accumulate in the liver and spleen. These data provide, for the first time, a quantitative measurement of the in vivo targeting efficacy of an inorganic nanoparticle-mAb system.

Woodward, Jonathan [ORNL; Kennel, Steve J [ORNL; Mirzadeh, Saed [ORNL; Dai, Sheng [ORNL; Rondinone, Adam Justin [ORNL

2007-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "zn zurn ot" from the National Library of EnergyBeta (NLEBeta).
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321

Comparison of CdTe and CdZnTe Detectors for Field Determination of Uranium Isotopic Enrichments  

DOE Green Energy (OSTI)

A performance comparison of a CdTe and a CdZnTe detector when exposed to uranium samples of various isotopic enrichments has been performed. These high-resolution detectors can assist in the rapid determination of uranium isotopic content of illicit material. Spectra were recorded from these room temperature semiconductor detectors with a portable multi-channel analyzer, both in the laboratory and in a field environment. Both detectors were operated below ambient temperature using the vendor supplied thermoelectric coolers. Both detectors had nominally the same active volume (18 mm3 for the CdZnTe and 25 mm3 for the CdTe detector) and resolution. Spectra of samples of known isotopic content were recorded at fixed geometries. An evaluation of potential signature g rays for the detection of enriched uranium was completed. Operational advantages and disadvantages of each detector are discussed. There is a need to improve the detection sensitivity during the interdiction of special nuclear materials (SNM) for increased homeland protection. It is essential to provide additional tools to first responders and law enforcement personnel for assessing nuclear and radiological threats.

Hofstetter, KJ

2004-01-23T23:59:59.000Z

322

Effect of AZO substrates on self-seeded electrochemical growth of vertically aligned ZnO nanorod arrays and their optical properties  

Science Conference Proceedings (OSTI)

We present a single step and an electrochemical synthesis of vertically aligned ZnO nanorod (NR) arrays, directly on transparent aluminium-doped zinc oxide (AZO) electrodes. The NRs grow from mild, aqueous-based solution at low temperature, with no need ...

A. Pei?; T. Dimopoulos; R. Resel; S. Abermann; M. Postl; E. J. W. List; H. Brückl

2012-01-01T23:59:59.000Z

323

Four-body continuum-discretized coupled-channels calculations: Application to {sup 6}He+{sup 64}Zn at 13.6 MeV  

Science Conference Proceedings (OSTI)

The recently developed four-body continuum-discretized coupled-channels (CDCC) method, making use of the binning procedure, is applied to the reaction {sup 6}He+{sup 64}Zn at 13.6 MeV (around the Coulomb barrier). Excellent agreement with available elastic data is found.

Rodriguez-Gallardo, M. [IEM, CSIC, Serrano 123, 28006 Madrid (Spain); Depto. FAMN, Universidad de Sevilla, Apdo. 1065, Sevilla (Spain); Arias, J. M.; Moro, A. M. [Depto. FAMN, Universidad de Sevilla, Apdo. 1065, Sevilla (Spain); Gomez-Camacho, J. [Depto. FAMN, Universidad de Sevilla, Apdo. 1065, Sevilla (Spain); CNA, Av. Thomas A. Edison 7, 41092 Sevilla (Spain); Thompson, I. J. [LLNL, PO Box 808, Livermore, CA 94551 (United States); Tostevin, J. A. [Department of Physics, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)

2010-04-26T23:59:59.000Z

324

A Novel Combustion Synthesis Preparation of CuO/ZnO/ZrO2/Pd for Oxidative Hydrogen Production from Methanol  

E-Print Network (OSTI)

A Novel Combustion Synthesis Preparation of CuO/ZnO/ZrO2/Pd for Oxidative Hydrogen Production from pre- pared via three combustion synthesis routes including volume combustion, impregnated substrate combustion, and so-called second wave impregnation combustion methods. These catalysts were characterized via

Mukasyan, Alexander

325

Epitaxial growth on silicon and characterization of MnF{sub 2} and ZnF{sub 2} layers with metastable orthorhombic structure  

SciTech Connect

The growth of MnF{sub 2} and ZnF{sub 2} layers on Si(001) and Si(111) substrates was studied by molecular-beam epitaxy. Calcium fluoride buffer layers with (001) (110), and (111) orientations were used to prevent chemical interaction of MnF{sub 2} and ZnF{sub 2} molecules with the Si substrate. The analysis of x-ray and reflection high-energy electron-diffraction (RHEED) patterns showed that MnF{sub 2} layers grow on all of these planes in the orthorhombic {alpha}-PbO{sub 2}-type crystal phase observed earlier only at high pressures and temperatures. Atomic force microscopy revealed a strong dependence of the surface morphology on the buffer orientation and growth temperature. The best-ordered MnF{sub 2} growth occurred at 500 deg. C on a CaF{sub 2} (110) buffer layer. The diffraction analysis enabled us to find the epitaxial relations at the MnF{sub 2}/CaF{sub 2} interface. A careful analysis of the RHEED patterns of the films grown on CaF{sub 2}(001) showed a similarity in the structure and growth modes between MnF{sub 2} and ZnF{sub 2} layers, with ZnF{sub 2} tending to form multiphase layers. These findings are in agreement with the x-ray diffraction measurements.

Kaveev, A.K.; Anisimov, O.V.; Banshchikov, A.G.; Kartenko, N.F.; Ulin, V.P.; Sokolov, N.S. [Ioffe Physico-Technical Institute Russian Academy of Sciences, St. Petersburg 194021 (Russian Federation)

2005-07-01T23:59:59.000Z

326

Effects of Cu Diffusion from ZnTe:Cu/Ti Contacts on Carrier Lifetime of CdS/CdTe Thin Film Solar Cells: Preprint  

DOE Green Energy (OSTI)

We study the performance of CdS/CdTe thin film PV devices processed with a ZnTe:Cu/Ti contact to investigate how carrier lifetime in the CdTe layer is affected by Cu diffusion from the contact.

Gessert, T. A.; Metzger, W. K.; Asher, S. E.; Young, M. R.; Johnston, S.; Dhere, R. G.; Duda, A.

2008-05-01T23:59:59.000Z

327

Energy Transfer Dynamics and Dopant Luminescence in Mn-Doped CdS/ZnS Core/Shell Nanocrystals  

E-Print Network (OSTI)

Mn-doped II-VI semiconductor nanocrystals exhibit bright dopant photoluminescence that has potential usefulness for light emitting devices, temperature sensing, and biological imaging. The bright luminescence comes from the 4T1?6A1 transition of the Mn2+ d electrons after the exciton-dopant energy transfer, which reroutes the exciton relaxation through trapping processes. The driving force of the energy transfer is the strong exchange coupling between the exciton and Mn2+ due to the confinement of exciton in the nanocrystal. The exciton-Mn spatial overlap affecting the exchange coupling strength is an important parameter that varies the energy transfer rate and the quantum yield of Mn luminescence. In this dissertation, this correlation is studied in radial doping location-controlled Mn-doped CdS/ZnS nanocrystals. Energy transfer rate was found decreasing when increasing the doping radius in the nanocrystals at the same core size and shell thickness and when increasing the size of the nanocrystals at a fixed doping radius. In addition to the exciton-Mn energy transfer discussed above, two consecutive exciton-Mn energy transfers can also occur if multiple excitons are generated before the relaxation of Mn (lifetime ~10^-4 - 10^-2 s). The consecutive exciton-Mn energy transfer can further excite the Mn2+ d electrons high in conduction band and results in the quenching of Mn luminescence. The highly excited electrons show higher photocatalytic efficiency than the electrons in undoped nanocrystals. Finally, the effect of local lattice strain on the local vibrational frequency and local thermal expansion was observed via the temperature-dependent Mn luminescence spectral linewidth and peak position in Mn-doped CdS/ZnS nanocrystals. The local lattice strain on the Mn2+ ions is varied using the large core/shell lattice mismatch (~7%) that creates a gradient of lattice strain at various radial locations. When doping the Mn2+ closer to the core/shell interface, the stronger lattice strain softens the vibrational frequency coupled to the 4T1?6A1 transition of Mn2+ (Mn luminescence) by ~50%. In addition, the lattice strain also increases the anharmonicity, resulting in larger local thermal expansion observed from the nearly an order larger thermal shift of the Mn luminescence compared to the Mn-doped ZnS nanocrystals without the core/shell lattice mismatch.

Chen, Hsiang-Yun

2012-12-01T23:59:59.000Z

328

Catalytic activity of a series of Zn(II) phenoxides for the copolymerization of epoxides and carbon dioxide  

Science Conference Proceedings (OSTI)

A series of zinc phenoxides of the general formula (2,6-R{sub 2}C{sub 6}H{sub 3}O){sub 2}Zn(base){sub 2} [R = Ph, {sup t}Bu, {sup i}Pr, base = Et{sub 2}O, THF, or propylene carbonate] and (2,4,6-Me{sub 3}C{sub 6}H{sub 2}O){sub 2}Zn(pyridine){sub 2} have been synthesized and characterized in the solid state by X-ray crystallography. All complexes crystallized as four-coordinate monomers with highly distorted tetrahedral geometry about the zinc center. The angles between the two sterically encumbering phenoxide ligands were found to be significantly more obtuse than the corresponding angles between the two smaller neutral base ligands, having average values of 140{degree} and 95{degree}, respectively. In a noninteracting solvent such as benzene or methylene chloride at ambient temperature, the ancillary base ligands are extensively dissociated from the zinc center, with the degree of dissociation being dependent on the base as well as the substituents on the phenolate ligands. That is, stronger ligand binding was found in zinc centers containing electron-donating tert-butyl substituents as opposed to electron-withdrawing phenyl substituents. In all instances, the order of ligand binding was pyridine > THF > epoxides. These bis(phenoxide) derivatives of zinc were shown to be very effective catalysts for the copolymerization of cyclohexene oxide and CO{sub 2} in the absence of strongly coordinating solvents, to afford high-molecular-weight polycarbonate (M{sub w} ranging from 45 x 10{sup 3} to 173 x 10{sup 3} Da) with low levels of polyether linkages. However, under similar conditions, these zinc complexes only coupled propylene oxide and CO{sub 2} to produce cyclic propylene carbonate. Nevertheless, these bis(phenoxide) derivatives of zinc were competent at terpolymerization of cyclohexene oxide/propylene oxide/CO{sub 2} with little cyclic propylene carbonate formation at low propylene oxide loadings. While CO{sub 2} showed no reactivity with the sterically encumbered zinc bis(phenoxides), e.g., (2,6-di-tert-butylphenoxide){sub 2}Zn(pyridine){sub 2} to provide the corresponding aryl carbonate zinc derivative. At the same time, both sterically hindered and sterically nonhindered phenoxide derivatives of zinc served to ring-open epoxide, i.e., were effective catalysts for the homopolymerization of epoxide to polyethers. The relevance of these reactivity patterns to the initiation step of the copolymerization process involving these monomeric zinc complexes is discussed.

Darensbourg, D.J.; Holtcamp, M.W.; Struck, G.E.; Zimmer, M.S.; Niezgoda, S.A.; Rainey, P.; Robertson, J.B.; Draper, J.D.; Reibenspies, J.H.

1999-01-13T23:59:59.000Z

329

Evolution of local structures in polycrystalline Zn1?xMgxO (0<=x<=0.15) studied by Raman spectroscopy and synchrotron x-ray pair-distribution-function analysis  

SciTech Connect

The local structures of Zn{sub 1-x}Mg{sub x}O alloys have been studied by Raman spectroscopy and by synchrotron x-ray pair-distribution-function (PDF) analysis. Within the solid solution range (0 {le} x {le} 0.15) of Zn{sub 1-x}Mg{sub x}O, the wurtzite framework is maintained with Mg homogeneously distributed throughout the wurtzite lattice. The E{sub 2}{sup high} Raman line of Zn{sub 1-x}Mg{sub x}O displays systematic changes in response to the evolution of the crystal lattice upon the Mg substitution. The redshift and broadening of the E{sub 2}{sup high} mode are explained by the expansion of hexagonal ab dimensions and compositional disorder of Zn/Mg, respectively. Synchrotron x-ray PDF analyses of Zn{sub 1-x}Mg{sub x}O reveal that the Mg atoms have a slightly reduced wurtzite parameter u and more regular tetrahedral bond distances than the Zn atoms. For both Zn and Mg, the internal tetrahedral geometries are independent of the alloy composition.

Kim, Young-Il; Page, Katharine; Limarga, Andi M.; Clarke, David R.; Seshadri, Ram (UCSB)

2008-09-18T23:59:59.000Z

330

Photoluminescence associated with basal stacking faults in c-plane ZnO epitaxial film grown by atomic layer deposition  

Science Conference Proceedings (OSTI)

Basal plane stacking faults (BSFs) with density of {approx}1 x 10{sup 6} cm{sup -1} are identified as the dominant defect in the annealed ZnO thin films grown on c-plane sapphire by atomic layer deposition. The dominant peak centered at 3.321 eV in low-temperature photoluminescence measurements is attributed to the emission from the BSFs. The emission mechanism is considered to be the confined indirect excitons in the region of quantum-well-like structure formed by the BSFs. The observed energy shift of 19 meV with respect to the BSF-bounded exciton at low temperature may be caused by the localization effect associated with the coupling between BSF quantum wells.

Yang, S.; Kuo, C. C.; Hsieh, W. F. [Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Liu, W.-R. [Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan (China); Lin, B. H. [Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan (China); Hsu, H.-C. [Institute of Electro-Optical Science and Engineering and Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 70101, Taiwan (China); Hsu, C.-H. [Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan (China); Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan (China)

2012-03-05T23:59:59.000Z

331

High quality ZnO:Al transparent conducting oxide films synthesized by pulsed filtered cathodic arc deposition  

Science Conference Proceedings (OSTI)

Aluminum-doped zinc oxide, ZnO:Al or AZO, is a well-known n-type transparent conducting oxide with great potential in a number of applications currently dominated by indium tin oxide (ITO). In this study, the optical and electrical properties of AZO thin films deposited on glass and silicon by pulsed filtered cathodic arc deposition are systematically studied. In contrast to magnetron sputtering, this technique does not produce energetic negative ions, and therefore ion damage can be minimized. The quality of the AZO films strongly depends on the growth temperature while only marginal improvements are obtained with post-deposition annealing. The best films, grown at a temperature of about 200?C, have resistivities in the low to mid 10-4 Omega cm range with a transmittance better than 85percent in the visible part of the spectrum. It is remarkable that relatively good films of small thickness (60 nm) can be fabricated using this method.

Anders, Andre; Lim, Sunnie H.N.; Yu, Kin Man; Andersson, Joakim; Rosen, Johanna; McFarland, Mike; Brown, Jeff

2009-04-24T23:59:59.000Z

332

Origins of the Doping Asymmetry in Oxides: Hole Doping in NiO versus Electron Doping in ZnO  

Science Conference Proceedings (OSTI)

The doping response of the prototypical transparent oxides NiO (p-type), ZnO (n-type), and MgO (insulating) is caused by spontaneous formation of compensating centers, leading to Fermi-level pinning at critical Fermi energies. We study the doping principles in these oxides by first-principles calculations of carrier-producing or -compensating defects and of the natural band offsets, and identify the dopability trends with the ionization potentials and electron affinities of the oxides. We find that the room-temperature free-hole density of cation-deficient NiO is limited by a too large ionization energy of the Ni vacancy, but it can be strongly increased by extrinsic dopants with shallower acceptor levels.

Lany, S.; Osorio-Guillen, J.; Zunger, A.

2007-01-01T23:59:59.000Z

333

Exciton photoluminescence and energy in a percolation cluster of ZnSe quantum dots as a fractal object  

SciTech Connect

The results of studies of samples containing ZnSe quantum dots with a density corresponding to or considerably higher than the exciton percolation threshold, at which quantum dots form conglomerates, are reported. Excitonic emission from a percolation cluster of bound quantum dots as a fractal object is observed for the first time. Analysis of the structure of the photoluminescence spectra shows that the spectra are determined by the contribution of exciton states that belong to different structural elements of the percolation cluster, specifically, to the skeleton (backbone), dangling (dead) ends, and internal hollow spaces. A qualitative model is proposed to interpret the dependence of the exciton energy in these structural elements on the concentration of quantum dots in the material.

Bondar, N. V., E-mail: jbond@iop.kiev.ua; Brodyn, M. S. [National Academy of Sciences of Ukraine, Institute of Physics (Ukraine)

2012-05-15T23:59:59.000Z

334

Epitaxial growth and photochemical annealing of graded CdS/ZnS shells on colloidal CdSe nanorods  

SciTech Connect

We report the preparation and structural characterization of core/shell CdSe/CdS/ZnS nanorods. A graded shell of larger band gap is grown around CdSe rods using trioctylphosphine oxide as a surfactant. Interfacial segregation is used to preferentially deposit CdS near the core, providing relaxation of the strain at the core/shell interface. The reported synthesis allows for variation of the shell thickness between one and six monolayers, on core nanorods ranging from aspect ratios of 2:1 to 10:1. After an irreversible photochemical annealing process, the core/shell nanorods have increased quantum efficiencies and are stable in air under visible or UV excitation. In addition to their robust optical properties, these samples provide an opportunity for the study of the evolution of epitaxial strain as the shape of the core varies from nearly spherical to nearly cylindrical.

Manna, Liberato; Scher, Erik C.; Li, Liang-shi; Alivisatos, A. Paul

2002-02-14T23:59:59.000Z

335

Origin of instability by positive bias stress in amorphous Si-In-Zn-O thin film transistor  

Science Conference Proceedings (OSTI)

The origin of instability under positive bias stress (PBS) in amorphous Si-In-Zn-O (SIZO) thin film transistor (TFT) with different Si concentration has been investigated by x-ray photoelectron spectroscopy (XPS) and density of states (DOSs) analysis. It is found that stability of SIZO-TFT with 3 wt. % Si under PBS became more deteriorated than that of 1 wt. % Si incorporated SIZO-TFT due to the increased oxygen related trap distributed in energy range from conduction band to {approx}0.3 eV below the conduction band. The origin of instability under PBS was discussed in terms of oxygen related trap derived from DOSs and XPS analysis.

Hyung Kim, Do [Department of Semiconductor Engineering, Cheongju University, Cheongju, Chungbuk 360-764 (Korea, Republic of); Department of Physics, University of Dongguk, Seoul 100-715 (Korea, Republic of); Youn Yoo, Dong [Future Convergence Research Division, Korea Institute of Science and Technology, Seoul 130-012 (Korea, Republic of); Kwang Jung, Hyun; Hwan Kim, Dae [School of Electrical Engineering, Kookmin University, Seoul 136-702 (Korea, Republic of); Yeol Lee, Sang [Department of Semiconductor Engineering, Cheongju University, Cheongju, Chungbuk 360-764 (Korea, Republic of)

2011-10-24T23:59:59.000Z

336

Investigation of Charge Transport Properties of CdZnTe Detectors with Synchrotron X-ray Radiation  

Science Conference Proceedings (OSTI)

Various internal defects, such as Te inclusions, twin boundaries, dislocation, etc., are prevalent in as-grown CdZnTe (CZT) crystals, which affect the charge transport properties of CZT crystals and, therefore, worsen the performance of CZT detectors. In order to develop high quality CZT detectors, it is imperative to clarify the effects of internal defects on the charge transport properties of CZT. Simple flood illumination with nuclear radiation source cannot reveal the nature of highly localized defects in CZT. Therefore, at Brookhaven's National Synchrotron Light Source (NSLS), we have developed a unique testing system for micro-scale defect investigation of CZT, which employs an X-ray beam collimated with the spatial resolution as small as 3 x 3 {micro}m{sup 2}, a microscopic size comparable to the scale of common defects in CZT. This powerful tool enables us to investigate the effect of internal defects on charge transport properties of CZT in detail.

Yang,G.; Bolotnikov, A.E.; Camarda, G.S.; Cui, Y.; Hossain, A.; James, R.B.

2008-10-19T23:59:59.000Z

337

An effect of the networks of the subgrain boundaries on spectral responses of thick CdZnTe detectors  

Science Conference Proceedings (OSTI)

CdZnTe (CZT) crystals used for nuclear-radiation detectors often contain high concentrations of subgrain boundaries and networks of poligonized dislocations that can significantly degrade the performance of semiconductor devices. These defects exist in all commercial CZT materials, regardless of their growth techniques and their vendor. We describe our new results from examining such detectors using IR transmission microscopy and white X-ray beam diffraction topography. We emphasize the roles on the devices performances of networks of subgrain boundaries with low dislocation densities, such as poligonized dislocations and mosaic structures. Specifically, we evaluated their effects on the gamma-ray responses of thick, >10 mm, CZT detectors. Our findings set the lower limit on the energy resolution of CZT detectors containing dense networks of subgrain boundaries, and walls of dislocations.

Bolotnikov, A.; Butcher, J.; Camarda, G.; Cui, Y.; Egarievwe, S.; Fochuk, P.; Gul,R.; Hamade, M.; Hossain, A.; Kim, K.; Kopach,O.; Petryk, M.; Raghothamachar, B.; Yang, G.; and James, R.B.

2011-08-12T23:59:59.000Z

338

Energy band alignment of InGaZnO{sub 4}/Si heterojunction determined by x-ray photoelectron spectroscopy  

SciTech Connect

X-ray photoelectron spectroscopy was utilized to determine the valence band offset ({Delta}E{sub V}) of the InGaZnO{sub 4} (IGZO)/Si heterojunction. The IGZO films were grown on Si (100) using radio frequency magnetron sputtering. A value of {Delta}E{sub V} = 2.53 eV was obtained by using In 3d{sub 5/2}, Ga 2p{sub 3/2} core energy levels as references. Taking into consideration the experimental band gap of 3.20 eV of the IGZO, this would result in a conduction band offset {Delta}E{sub C} = 0.45 eV in this heterostructure.

Xie Zhangyi; Lu Hongliang; Xu Saisheng; Geng Yang; Sun Qingqing; Ding Shijin; Zhang, David Wei [State Key Laboratory of ASIC and System, Department of Microelectronics, Fudan University, Shanghai 200433 (China)

2012-12-17T23:59:59.000Z

339

Effect of aging on the fatigue crack growth kinetics of an Al-Zn-Mg-Cu alloy in two directions  

Science Conference Proceedings (OSTI)

There have been investigations discussing the effect of aging condition, and thereby the microstructure, on the fatigue crack growth characteristics of precipitation hardening alloys. Lindigkeit et al.., testing an Al-Zn-Mg-Cu alloy of composition corresponding to the commercial alloy 7075 concluded that the crack propagation resistance of underaged microstructures with shearable precipitates is significantly higher than overaged samples of same strength containing non-shearable particles. They reported that this behavior cannot be explained on the basis of slip reversibility alone. A similar conclusion is drawn by Zaiken and Ritchie from investigations on the effect of microstructure on the fatigue crack growth rate of an 7150 aluminum alloy, which is a somewhat high-purity version of the alloy 7050, with lower Fe and Si contents. It is also interesting that aging conditions showing high resistance to fatigue crack growth at low [Delta]K regimes, do not necessarily retain their superiority at medium and high stress intensity ranges.

Alpay, S.P.; Guerbuez, R. (Middle East Technical Univ., Ankara (Turkey). Dept. of Metallurgical Engineering)

1994-02-15T23:59:59.000Z

340

Formation of ZnTe:Cu/Ti Contacts at High Temperature for CdS/CdTe Devices (Presentation)  

DOE Green Energy (OSTI)

The conclusions of this report are that Cu diffusion from a ZnTe:Cu contact causes good and bad things. The good (Cu in CdS < low 10{sup 18} cm{sup -3})--increase in CdTe N{sub A}-N{sub D} that leads to V{sub oc} and FF improvement. The bad (Cu in CdS > low 10{sup 18} cm{sup -3})--(1) possibly decreased of shunt resistance (?); (2) depletion width in CdTe can become too narrow for optimum current collection at J{sub MPP}; (3) donor reduction in CdS (significant FF loss in LIV); and (4) excessive Cu diffusion into CdS readily observed by red-light bias QE.

Gessert, T. A.; Asher, S.; Johnston, S.; Duda, A.; Young, M. R.; Moriarty, T.

2006-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "zn zurn ot" from the National Library of EnergyBeta (NLEBeta).
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341

Simulation, Modeling, and Crystal Growth of Cd0.9Zn0.1Te for Nuclear Spectrometers  

Science Conference Proceedings (OSTI)

High-quality, large (10 cm long and 2.5 cm diameter), nuclear spectrometer grade Cd{sub 0.9}Zn{sub 0.1}Te (CZT) single crystals have been grown by a controlled vertical Bridgman technique using in-house zone refined precursor materials (Cd, Zn, and Te). A state-of-the-art computer model, multizone adaptive scheme for transport and phase-change processes (MASTRAP), is used to model heat and mass transfer in the Bridgman growth system and to predict the stress distribution in the as-grown CZT crystal and optimize the thermal profile. The model accounts for heat transfer in the multiphase system, convection in the melt, and interface dynamics. The grown semi-insulating (SI) CZT crystals have demonstrated promising results for high-resolution room-temperature radiation detectors due to their high dark resistivity ({rho} {approx} 2.8 x 10{sup 11} {Theta} cm), good charge-transport properties, electron and hole mobility-life-time product, {mu}{tau}{sub e} {approx} (2-5) x 10{sup -3} and {mu}{tau}{sub h} {approx} (3-5) x 10{sup -5} respectively, and low cost of production. Spectroscopic ellipsometry and optical transmission measurements were carried out on the grown CZT crystals using two-modulator generalized ellipsometry (2-MGE). The refractive index n and extinction coefficient k were determined by mathematically eliminating the {approx}3-nm surface roughness layer. Nuclear detection measurements on the single-element CZT detectors with {sup 241}Am and {sup 137}Cs clearly detected 59.6 and 662 keV energies with energy resolution (FWHM) of 2.4 keV (4.0%) and 9.2 keV (1.4%), respectively.

Mandal, Krishna [EIC Laboratories, Inc.; Kang, Sung Hoon [EIC Laboratories, Inc.; Choi, Michael [EIC Laboratories, Inc.; Bello, Job [EIC Laboratories, Inc.; Zheng, Lili [State University of New York, Stony Brook; Zhang, Hui [State University of New York, Stony Brook; Groza, Michael [Fisk University, Nashville, TN; Roy, Utpal N. [Fisk University, Nashville, TN; Burger, Arnold [Fisk University, Nashville, TN; Jellison Jr, Gerald Earle [ORNL; Holcomb, David Eugene [ORNL; Wright, Gomez W [ORNL; Williams, Joseph A [ORNL

2006-01-01T23:59:59.000Z

342

Aggregation Kinetics of Metal Chalcogenide Nanocrystals: Generation of Transparent CdSe(ZnS) Core(Shell) Gels  

Science Conference Proceedings (OSTI)

Transparent CdSe (ZnS) core (shell) sol–gel materials have potential uses in optoelectronic applications such as light-emitting diodes (LEDs) due to their strong luminescence properties and the potential for charge transport through the prewired nanocrystal (NC) network of the gel. However, typical syntheses of metal chalcogenide gels yield materials with poor transparency. In this work, the mechanism and kinetics of aggregation of two sizes of CdSe (ZnS) core (shell) NCs, initiated by removal of surface thiolate ligands using tetranitromethane (TNM) as an oxidant, were studied by means of time-resolved dynamic light scattering (TRDLS); the characteristics of the resultant gels were probed by optical absorption, transmission electron microscopy (TEM), and small-angle X-ray scattering (SAXS). At low concentrations of NCs (ca. 4 × 10{sup –7} M), the smaller, green-emitting NCs aggregate faster than the larger, orange-emitting NCs, for a specific oxidant concentration. The kinetics of aggregation have a significant impact on the macroscopic properties (i.e., transparency) of the resultant gels, with the transparency of the gels decreasing with the increase of oxidant concentration due the formation of larger clusters at the gel point and a shift away from a reaction-limited cluster-aggregation (RLCA) mechanism. This is further confirmed by analyses of the gel structures by SAXS and TEM. Likewise, the larger orange-emitting particles also produce larger aggregates at the gel point, leading to lower transparency. The ability to control the transparency of chalcogenide gels will enable their properties to be tuned in order to address application-specific needs in optoelectronics.

Korala, Lasantha; Brock, Stephanie

2012-01-01T23:59:59.000Z

343

X-ray spectroscopic study of the charge state and local orderingof room-temperature ferromagnetic Mn oped ZnO  

Science Conference Proceedings (OSTI)

The charge state and local ordering of Mn doped into a pulsed laser deposited single-phase thin film of ZnO are investigated by using X-ray absorption spectroscopy at the O K-, Mn K- and L-edges, and X-ray emission spectroscopy at the O K- and Mn L-edge. This film is found to be ferromagnetic at room temperature. EXAFS measurement shows that Mn{sup 2+} replaces Zn site in tetrahedral symmetry, and there is no evidence for either metallic Mn or MnO in the film. Upon Mn doping, the top of O 2p valence band extends into the bandgap indicating additional charge carries being created.

Guo, J.-H.; Gupta, Amita; Sharma, Parmanand; Rao, K.V.; Marcus,M.A.; Dong, C.L.; Guillen, J.M.O.; Butorin, S.M.; Mattesini, M.; Glans,P.A.; Smith, K.E.; Chang, C.L.; Ahuja, R.

2007-08-07T23:59:59.000Z

344

Calculations of Branching Ratios for Radiative-Capture, One-Proton, and Two-Neutron Channels in the Fusion Reaction $^{209}$Bi+$^{70}$Zn  

E-Print Network (OSTI)

We discuss the possibility of the non-one-neutron emission channels in the cold fusion reaction $^{70}$Zn + $^{209}$Bi to produce the element Z=113. For this purpose, we calculate the evaporation-residue cross sections of one-proton, radiative-capture, and two-neutron emissions relative to the one-neutron emission in the reaction $^{70}$Zn + $^{209}$Bi. To estimate the upper bounds of those quantities, we vary model parameters in the calculations, such as the level-density parameter and the height of the fission barrier. We conclude that the highest possibility is for the 2n reaction channel, and its upper bounds are 2.4$%$ and at most less than 7.9% with unrealistic parameter values, under the actual experimental conditions of [J. Phys. Soc. Jpn. {\\bf 73} (2004) 2593].

Takatoshi Ichikawa; Akira Iwamoto

2010-12-20T23:59:59.000Z

345

Calculations of Branching Ratios for Radiative-Capture, One-Proton, and Two-Neutron Channels in the Fusion Reaction $^{209}$Bi+$^{70}$Zn  

E-Print Network (OSTI)

We discuss the possibility of the non-one-neutron emission channels in the cold fusion reaction $^{70}$Zn + $^{209}$Bi to produce the element Z=113. For this purpose, we calculate the evaporation-residue cross sections of one-proton, radiative-capture, and two-neutron emissions relative to the one-neutron emission in the reaction $^{70}$Zn + $^{209}$Bi. To estimate the upper bounds of those quantities, we vary model parameters in the calculations, such as the level-density parameter and the height of the fission barrier. We conclude that the highest possibility is for the 2n reaction channel, and its upper bounds are 2.4$%$ and at most less than 7.9% with unrealistic parameter values, under the actual experimental conditions of [J. Phys. Soc. Jpn. {\\bf 73} (2004) 2593].

Ichikawa, Takatoshi; 10.1143/JPSJ.79.074201

2010-01-01T23:59:59.000Z

346

Impact of solid-phase crystallization of amorphous silicon on the chemical structure of the buried Si/ZnO thin film solar cell interface  

DOE Green Energy (OSTI)

The chemical interface structure between phosphorus-doped hydrogenated amorphous silicon and aluminum-doped zinc oxide thin films is investigated with soft x-ray emission spectroscopy (XES) before and after solid-phase crystallization (SPC) at 600C. In addition to the expected SPC-induced phase transition from amorphous to polycrystalline silicon, our XES data indicates a pronounced chemical interaction at the buried Si/ZnO interface. In particular, we find an SPC-enhanced formation of Si-O bonds and the accumulation of Zn in close proximity to the interface. For an assumed closed and homogeneous SiO2 interlayer, an effective thickness of (5+2)nm after SPC could be estimated.

Bar, M.; Wimmer, M.; Wilks, R. G.; Roczen, M.; Gerlach, D.; Ruske, F.; Lips, K.; Rech, B.; Weinhardt, L.; Blum, M.; Pookpanratana, S.; Krause, S.; Zhang, Y.; Heske, C.; Yang, W.; Denlinger, J. D.

2010-04-30T23:59:59.000Z

347

(Y0.5In0.5)Ba(Co,Zn)4O7 cathodes with superior high-temperature phase stability for solid oxide fuel cells  

Science Conference Proceedings (OSTI)

(Y0.5In0.5)BaCo4-xZnxO7 (1.0 x 2.0) oxides crystallizing in a trigonal P31c structure have been synthesized and explored as cathode materials for solid oxide fuel cells (SOFC). At a given Zn content, the (Y0.5In0.5)BaCo4-xZnxO7 sample with 50 % Y and 50 % In exhibits much improved phase stability at intermediate temperatures (600 - 800 oC) compared to the samples with 100 % Y or In. However, the substitution of Zn for Co in (Y0.5In0.5)Ba(Co4-xZnx)O7 (1.0 x 2.0) decreases the amount of oxygen loss on heating, total electrical conductivity, and cathode performance in SOFC while providing good long-term phase stability at high temperatures. Among the various chemical compositions investigated in the (Y0.5In0.5)Ba(Co4-xZnx)O7 system, the (Y0.5In0.5)BaCo3ZnO7 sample offers a combination of good electrochemical performance and low thermal expansion coefficient (TEC) while maintaining superior phase stability at 600 800 oC for 100 h. Fuel cell performances of the (Y0.5In0.5)Ba(Co3Zn)O7 + Ce0.8Gd0.2O1.9 (GDC) (50 : 50 wt. %) composite cathodes collected with anode-supported single cell reveal a maximum power density value of 521 mW cm-2 at 700 oC.

Young Nam, Kim [University of Texas, Austin; Kim, Jung-Hyun [ORNL; Paranthaman, Mariappan Parans [ORNL; Manthiram, Arumugam [University of Texas, Austin; Huq, Ashfia [ORNL

2012-01-01T23:59:59.000Z

348

Influence of delay step conditions between quenching and aging on the precipitation mechanisms in the alloy AlZnMg AA7028 aging process  

Science Conference Proceedings (OSTI)

Among precipitation-hardened alloys, the Al-Zn-Mg system includes the aluminium alloys with higher-strength. The relatively high solubility of Zn and Mg in aluminium makes it possible to produce a high density of precipitates, which results in a higher strength increase. AlZnMg low copper or copper free alloys have the advantage of being easily weldable and, moreover, they harden significantly at room temperature with respect to other weldable aluminium alloys. Due to the remarkable degree of natural aging achieved by AA7000 alloys, the time interval at room temperature between quenching and the beginning of the artificial aging treatment is a variable that must be taken into account. This work was undertaken to evaluate the influence of cooling kinetics at quenching on alloy mechanical characteristics in artificial aging at several temperatures T{sub 2}. The effect of variables that define delays after quenching, basically time t{sub 1} and temperature T{sub 1} was also analyzed. Likewise, this work studies microstructural evolution of material exposed to aging treatments, resulting from the combination of the above mentioned variables.

Calatayud, A. [Univ. de Castilla-La Mancha, Albacete (Spain). Ciencia de los Materiales] [Univ. de Castilla-La Mancha, Albacete (Spain). Ciencia de los Materiales; Ferrer, C.; Amigo, V.; Salvador, M.D. [Univ. Politecnica de Valencia (Spain). Ingenieria Mecanica y de los Materiales] [Univ. Politecnica de Valencia (Spain). Ingenieria Mecanica y de los Materiales

1997-03-15T23:59:59.000Z

349

Zn13(CrxAl1-x)27 (x = 0.34-0.37): a new intermetallic phase containing icosahedra as building units  

SciTech Connect

The title compounds Zn{sub 13}(Cr{sub x}Al{sub 1-x}){sub 27} (x = 0.34-0.37) were obtained by melting the pure elements at 923 K, and followed by a heat treatment at 723 K in a tantalum container. According to single crystal structural analysis, the title compounds crystallize in the rhombohedral system, adopting a new structure type (R-3m, a = 7.5971(8), c = 36.816(6), for crystal I). Single crystal X-ray structural analysis reveals a statistical mixing of Cr/Al in their crystallographic positions. Single crystal and powder X-ray diffraction as well as energy dispersive X-ray analyses suggested the title phase to have a narrow homogeneity range. The substructure of Zn{sub 13}(Cr{sub x}Al{sub 1-x}){sub 27} shows close resemblance with the Mn{sub 3}Al{sub 10} structure type. A bonding analysis, through crystal orbital Hamiltonian populations (COHPs), of 'Cr{sub 9}Al{sub 18}Zn{sub 13}' as a representative composition indicated that both homo- and heteronuclear interactions are important for the stability of this new phase.

Thimmaiah, Srinivasa; Han, Mi-Kyung; Miller, Gordon J.

2011-03-13T23:59:59.000Z

350

Point Defects in Pb-, Bi-, and In-Doped CdZnTe Detectors:Deep-Level Transient Spectroscopy (DLTS) Measurements  

SciTech Connect

We studied, by current deep-level transient spectroscopy (I-DLTS), point defects induced in CdZnTe detectors by three dopants: Pb, Bi, and In. Pb-doped CdZnTe detectors have a new acceptor trap at around 0.48 eV. The absence of a V{sub Cd} trap suggests that all Cd vacancies are compensated by Pb interstitials after they form a deep-acceptor complex [[Pb{sub Cd}]{sup +}-V{sub Cd}{sup 2-}]{sup -}. Bi-doped CdZnTe detectors had two distinct traps: a shallow trap at around 36 meV and a deep donor trap at around 0.82 eV. In detectors doped with In, we noted three well-known traps: two acceptor levels at around 0.18 eV (A-centers) and 0.31 eV (V{sub Cd}), and a deep trap at around 1.1 eV.

Bolotnikov A.; GUL, R.; KEETER, K.; RODRIGUEZ, R.; BOLOTNIKOV, A.E.; HOSSAIN, A.; CAMARDA, G.S.; KIM, K.H.; YANG, Y.; CUI, Y.; CARCELEN, V.; FRANC, J.; LI, Z.; JAMES, R.B.

2012-02-29T23:59:59.000Z

351

CdSe/ZnS quantum dots based electrochemical immunoassay for the detection of phosphorylated bovine serum albumin  

SciTech Connect

A CdSe/ZnS quantum dot (QD) based electrochemical immunoassay of phosphorylated bovine serum albumin as a protein biomarker is presented. The QDs were used as labels and were conjugated with the secondary anti-phosphoserine antibody in a heterogeneous sandwich immunoassay. First, the primary BSA antibody was immobilized on polystyrene microwells, followed by the addition of BSA-OP. After that, the QD-labeled anti-phosphoserine antibody was added into microwells for immunorecognition. Finally, the bound QD was dissolved in an acid-dissolution step and was detected by electrochemical stripping analysis. The measured current responses were proportional to the concentration of BSA-OP. Under optimal conditions, the voltammetric response was linear over the range of 0.5 - 500 ng mL-1 of BSA-OP, with a detection limit of 0.5 ng mL-1 at a deposition potential of -1.2 V for 120 s. It also shows good reproducibility with a relative standard deviation of 8.6% of six times determination of 25 ng mL-1 of BSA-OP. This QD-based electrochemical immunoassay offers great promise for simple and cost-effective analysis of protein biomarkers.

Pinwattana, Kulwadee; Wang, Jun; Lin, Chiann Tso; Wu, Hong; Du, Dan; Lin, Yuehe; Chailapakul, Orawon

2010-11-15T23:59:59.000Z

352

CdTe and Cd0.9Zn0.1Te Crystal Growth and Characterization for Nuclear Spectrometers  

Science Conference Proceedings (OSTI)

Large volume single crystals of CdTe and Cd0.9Zn0.1Te (CZT) have been grown by a controlled vertical Bridgman technique using in-house zone refined precursors and characterized through structural, electrical, optical, and spectroscopic methods. The grown crystals (diameter greater than or equal to 2.5 cm and length >10 cm) have shown promising characteristics for high-resolution room temperature solid-state radiation detectors due to their high resistivity (~1010 -cm for CdTe, and >1011 -cm for CZT) and good charge transport properties [ e ~ (2-5)x10-3 cm2/V]. The fabricated detectors in planar single element and Frisch collar configurations have shown very low leakage currents and high count rates for various sources, including Am-241, and Cs-137. The grown crystals have been further characterized by X-ray diffraction (XRD), infrared spectroscopy (IR), and transmission two-modulator generalized ellipsometry (2-MGE). Details of the CdTe and CZT characterization results, detector fabrication steps, and testing with radiation sources are presented. The CdTe and CZT crystals have shown high prospects for low power rating solid-state nuclear spectrometers and medical imaging devices.

Mandal, Krishna [EIC Laboratories, Inc.; Kang, Sung Hoon [EIC Laboratories, Inc.; Choi, Michael [EIC Laboratories, Inc.; Wright, Gomez W [ORNL; Jellison Jr, Gerald Earle [ORNL

2006-01-01T23:59:59.000Z

353

The Structural Transition Behavior of CdSe/ZnS Core/shell Quantum Dots under High Pressure  

Science Conference Proceedings (OSTI)

The structural phase transition of CdSe/ZnS core/shell quantum dots (QDs) has been studied by in situ angle-dispersive X-ray diffraction under high pressure up to 53.6?GPa. The CdSe core transforms from wurtzite to rock-salt structure near 6.3?GPa and then to Cmcm or distorted Cmcm structure probably occurs at 45.1?GPa which has not been observed in CdSe nanomaterials before. The critical pressure from wurtzite to rock-salt and the bulk modulus of rock-salt phase are much higher than those for bulky and uncapped nanoparticle CdSe. The released sample can be kept in rock-salt phase for a certain time, verified by photoluminescence (PL) spectra, quite different from the reversible transition for pure CdSe. A reasonable interpretation of the experimental phenomena is given by comparing the bulk modulus of the core and shell and studying the stress sate of the core after decompression. Our study suggests that capping a hard shell is an effective approach to quench the high pressure phase of nanomaterial with a reversible phase transition.

Z Li; L Wang; B Liu; J Wang; B Liu; Q Li; B Zou; T Cui; Y Meng; H Mao

2011-12-31T23:59:59.000Z

354

Phase identification and control of thin films deposited by co-evaporation of elemental Cu, Zn, Sn, and Se  

Science Conference Proceedings (OSTI)

Kesterite thin films [(i.e., Cu{sub 2}ZnSn(S,Se){sub 4} and related alloys] have been the subject of recent interest for use as an absorber layer for thin film photovoltaics due to their high absorption coefficient (>10{sup 4} cm{sup -1}), their similarity to successful chalcopyrites (like CuInxGa{sub 1-x}Se{sub 2}) in structure, and their earth-abundance. The process window for growing a single-phase kesterite film is narrow. In this work, we have documented, for our 9.15%-efficient kesterite co-evaporation process, (1) how appearance of certain undesirable phases are controlled via choice of processing conditions, (2) several techniques for identification of phases in these films with resolution adequate to discern changes that are important to device performance, and (3) reference measurements for those performing such phase identification. Data from x-ray diffraction, x-ray fluorescence, Raman scattering, scanning electron microscopy, energy dispersive spectroscopy, and current-voltage characterization are presented.

Vora, Nirav; Blackburn, Jeffrey; Repins, Ingrid; Beall, Carolyn; To, Bobby; Pankow, Joel; Teeter, Glenn; Young, Matthew; Noufi, Rommel [National Renewable Energy Laboratory, 1617 Cole Blvd., MS 3219, Golden, Colorado 80401 (United States)

2012-09-15T23:59:59.000Z

355

Phase Identification and Control of Thin Films Deposited by Co-Evaporation of Elemental Cu, Zn, Sn, and Se  

Science Conference Proceedings (OSTI)

Kesterite thin films (i.e., Cu{sub 2}ZnSn(S,Se){sub 4} and related alloys) have been the subject of recent interest for use as an absorber layer for thin film photovoltaics due to their high absorption coefficient (> 10{sup 4} cm{sup -1}), their similarity to successful chalcopyrites (like CuInxGa{sub 1-x}Se{sub 2}) in structure, and their earth-abundance. The process window for growing a single-phase kesterite film is narrow. In this work, we have documented, for our 9.15%-efficient kesterite co-evaporation process, (1) how appearance of certain undesirable phases are controlled via choice of processing conditions, (2) several techniques for identification of phases in these films with resolution adequate to discern changes that are important to device performance, and (3) reference measurements for those performing such phase identification. Data from x-ray diffraction, x-ray fluorescence, Raman scattering, scanning electron microscopy, energy dispersive spectroscopy, and current-voltage characterization are presented.

Vora, N.; Blackburn, J.; Repins, I.; Beall, C.; To, B.; Pankow, J.; Teeter, G.; Young, M.; Noufi, R.

2012-09-01T23:59:59.000Z

356

Ingrain and grain boundary scattering effects on electron mobility of transparent conducting polycrystalline Ga-doped ZnO films  

Science Conference Proceedings (OSTI)

Transparent conducting polycrystalline Ga-doped ZnO (GZO) films with different thicknesses were deposited on glass substrates at a substrate temperature of 200 deg. C by ion-plating deposition with direct current arc-discharge. The dependences of crystal structure, electrical, and optical properties of the GZO films on thickness have been systematically studied. Optical response due to free electrons of the GZO films was characterized in the photon energy range from 0.73 to 3.8 eV by spectroscopic ellipsometry (SE). The free electron response was expressed by the simple Drude model combined with the Tauc-Lorentz model. From the SE analysis and the results of Hall measurements, electron effective mass, m{sup *}, and optical mobility, {mu}{sub opt}, of the GZO films were determined, based on the assumptions that the films are homogeneous and optically isotropic. By comparing the {mu}{sub opt} and Hall mobility, {mu}{sub Hall}, an indication on the effect of ingrain and grain boundary scattering limiting the electron mobility has been obtained. Moreover, the variation in scattering mechanism causing thickness dependence of {mu}{sub Hall} was correlated with the development of polycrystalline grain structure.

Yamada, Takahiro; Makino, Hisao; Yamamoto, Naoki; Yamamoto, Tetsuya [Materials Design Center, Research Institute, Kochi University of Technology, 185 Miyanokuchi, Tosayamada-cho, Kami-shi, Kochi 782-8502 (Japan)

2010-06-15T23:59:59.000Z

357

The influence of substrate temperature on the structural and optical properties of ZnS thin films  

SciTech Connect

Thin films of ZnS were deposited on soda lime glass substrates by a modified close-space sublimation technique. The change in optical and structural properties of the films deposited at various substrate temperatures (150-450 Degree-Sign C) was investigated. X-ray diffraction spectra showed that films were polycrystalline in nature having cubic structure oriented only along (111) plan. The crystallinity of films increased with the substrate temperature up to 250 Degree-Sign C. However, crystallinity decreased with further increase of substrate temperature and films became amorphous at 450 Degree-Sign C. The atomic force microscopy data revealed that the films become more uniform and dense with the increase of substrate temperature. Optical properties of the films were determined from the transmittance data using Swanepoel model. It was observed that the energy band gap is increased from 3.52 to 3.65 eV and refractive index of the films are decreased with the increase of substrate temperature. Moreover, considerable improvement in blue response of the films was noticed with increasing substrate temperature.

Ashraf, M.; Akhtar, S. M. J.; Ali, Z. [Optics Laboratories (Pakistan); Qayyum, A., E-mail: qayyum@pinstech.org.pk [Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Physics Division (Pakistan)

2011-05-15T23:59:59.000Z

358

Deep levels in a-plane, high Mg-content Mg{sub x}Zn{sub 1-x}O epitaxial layers grown by molecular beam epitaxy  

Science Conference Proceedings (OSTI)

Deep level defects in n-type unintentionally doped a-plane Mg{sub x}Zn{sub 1-x}O, grown by molecular beam epitaxy on r-plane sapphire were fully characterized using deep level optical spectroscopy (DLOS) and related methods. Four compositions of Mg{sub x}Zn{sub 1-x}O were examined with x = 0.31, 0.44, 0.52, and 0.56 together with a control ZnO sample. DLOS measurements revealed the presence of five deep levels in each Mg-containing sample, having energy levels of E{sub c} - 1.4 eV, 2.1 eV, 2.6 V, and E{sub v} + 0.3 eV and 0.6 eV. For all Mg compositions, the activation energies of the first three states were constant with respect to the conduction band edge, whereas the latter two revealed constant activation energies with respect to the valence band edge. In contrast to the ternary materials, only three levels, at E{sub c} - 2.1 eV, E{sub v} + 0.3 eV, and 0.6 eV, were observed for the ZnO control sample in this systematically grown series of samples. Substantially higher concentrations of the deep levels at E{sub v} + 0.3 eV and E{sub c} - 2.1 eV were observed in ZnO compared to the Mg alloyed samples. Moreover, there is a general invariance of trap concentration of the E{sub v} + 0.3 eV and 0.6 eV levels on Mg content, while at least and order of magnitude dependency of the E{sub c} - 1.4 eV and E{sub c} - 2.6 eV levels in Mg alloyed samples.

Guer, Emre [Department of Physics, Faculty of Science, Atatuerk University, Erzurum 25240 (Turkey); 205 Dreese Laboratory, Department of Electrical and Computer Engineering, The Ohio State University, 2015 Neil Avenue, Columbus, Ohio 43210-1272 (United States); Tabares, G.; Hierro, A. [Dpto. Ingenieria Electronica and ISOM, Universidad Politecnica de Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain); Arehart, A.; Ringel, S. A. [205 Dreese Laboratory, Department of Electrical and Computer Engineering, Ohio State University, 2015 Neil Avenue, Columbus, Ohio 43210-1272 (United States); Chauveau, J. M. [CRHEA-CNRS, 06560 Valbonne (France); University of Nice Sophia Antipolis, ParcValrose, 06102 Nice Cedex 2 (France)

2012-12-15T23:59:59.000Z

359

PR B_WY_C BM HILIGHT POWELL KIT TY WELL D RAW SC OT T MIKES D  

U.S. Energy Information Administration (EIA) Indexed Site

Gas Reserve Class Gas Reserve Class No 2001 gas reserves 0.1 - 10 MMCF 10.1 - 100 MMCF 100.1 - 1,000 MMCF 1,000.1 - 10,000 MMCF 10,000.1 - 100,000 MMCF > 100,000 MMCF Basin Outline CO Index Map For 2 Powder River Basin Panels WY MT SD NE ND Powder River Basin 1 2 NE Total Total Total Number Liquid Gas BOE of Reserves Reserves Reserves Fields (Mbbl) (MMcf) (Mbbl) Powder River 543 193,456 2,398,604 593,223 Basin 2001 Reserve Summary for All Powder River Basin Fields PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM The mapped oil and gas field boundary outlines were created by the Reserves and Production Division, Office of Oil and Gas,

360

Free Rud. Re,>.(ot?im.\\.. Vol. 15. No. 5, pp. 285-296 Reprints available directly from the publisher  

E-Print Network (OSTI)

of hydroquinone in bone marrow. the target organ of benzene-induced myelotoxicity. KEY WORDS: Benzene202,Hydrogen peroxide; HO', Hydroxyl radical; HQ, Hydro- quinone; HRP. Horseradish peroxidase; HX to phenol. Cytochrome P-450 has also been shown to hydroxylate phenol".I2 to hydroquinone (HQ) and catechol

California at Berkeley, University of

Note: This page contains sample records for the topic "zn zurn ot" from the National Library of EnergyBeta (NLEBeta).
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We encourage you to perform a real-time search of NLEBeta
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361

XRY*?m***x? :H8?JÆ ±???lâSEC o%t DAT??âÉFQ?D ...  

Science Conference Proceedings (OSTI)

XRY*?m***x? :H8?JÆ ±???lâSEC?o%t DAT??âÉFQ?D?????*qX* BMÄ*>(H***P*?*?** ?_ ¬? U ·½? ?W? Ç*?»? ? ß? } ? ?* } ƒ p ...

2008-05-13T23:59:59.000Z

362

PR B_WY_C BM HILIGHT POWELL KIT TY WELL D RAW SC OT T MIKES D  

U.S. Energy Information Administration (EIA) Indexed Site

Liquids Reserve Class Liquids Reserve Class No 2001 liquids reserves 0.1 - 10 Mbbl 10.1 - 100 Mbbl 100.1 - 1,000 Mbbl 1,000.1 - 10,000 Mbbl 10,000.1 - 100,000 Mbbl Basin Outline CO Index Map For 2 Powder River Basin Panels WY MT SD NE ND Powder River Basin 1 2 NE Total Total Total Number Liquid Gas BOE of Reserves Reserves Reserves Fields (Mbbl) (MMcf) (Mbbl) Powder River 543 193,456 2,398,604 593,223 Basin 2001 Reserve Summary for All Powder River Basin Fields PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM The mapped oil and gas field boundary outlines were created by the Reserves and Production Division, Office of Oil and Gas, Energy Information Administration pursuant to studies required by

363

PR B_WY_C BM HILIGHT POWELL KIT TY WELL D RAW SC OT T MIKES D  

U.S. Energy Information Administration (EIA) Indexed Site

BOE Reserve Class BOE Reserve Class No 2001 reserves 0.1 - 10 MBOE 10.1 - 100 MBOE 100.1 - 1,000 MBOE 1,000.1 - 10,000 MBOE 10,000.1 - 100,000 MBOE > 100,000 MBOE Basin Outline CO Index Map For 2 Powder River Basin Panels WY MT SD NE ND Powder River Basin 1 2 NE Total Total Total Number Liquid Gas BOE of Reserves Reserves Reserves Fields (Mbbl) (MMcf) (Mbbl) Powder River 543 193,456 2,398,604 593,223 Basin 2001 Reserve Summary for All Powder River Basin Fields PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM PR B_WY_C BM The mapped oil and gas field boundary outlines were created by the Reserves and Production Division, Office of Oil and Gas,

364

Nanoscale Measurements of the Surface Photovoltage in Cu(In,Ga)Se2, Cu2ZnSn4, and Cu2ZnSnSe4 Thin Films: The Role of the Surface Electronics on the Efficiency of Solar Cells: Preprint  

DOE Green Energy (OSTI)

We report on recent advances in the development of nanoscale measurements of the surface photovoltage (SPV) based on scanning tunneling microscopy (STM) and its application to the kesterites Cu2ZnSnS4 (CZTS) and Cu2ZnSnSe4 (CZTSe). One critical aspect of the electronic structure of Cu(In,Ga)Se2 (CIGS) that has yet to be determined in their related kesterite compounds is the character of the surface electronics. In CIGS, spontaneous deviations in the stoichiometry of the surface cause a depletion (or even a type inversion) region that reinforces the CIGS homojunction. First-principle calculations predict that this inversion region will be more difficult to form in CZTS. In this contribution, the characteristics of the surface space charge region for both CIGS and CZTS(e) are investigated by STM. The implications of the results of these measurements on the future development of CZTS solar cells will be discussed.

Du, H.; Romero, M. J.; Repins, I.; Teeter, G.; Noufi, R.; Al-Jassim, M. M.

2011-07-01T23:59:59.000Z

365

Electronic and Optical Properties of Spinel TCOs: Cd2SnO4, Zn2SnO4, and CdIn2O4  

DOE Green Energy (OSTI)

Using the band-structure method, we have studied the electronic and optical properties of the transparent conducting oxides SnZn2O4, SnCd2O4, and CdIn2O4. We analyzed the atomic and orbital characters of the band edge states and explained the general trends observed in the fundamental band gap, the optical band gap, the energy difference between the first and the second conduction bands, and the electron effective mass. General rules for designing more efficient transparent conducting oxides are proposed.

Wei, S. H.; Segev, D.

2005-01-01T23:59:59.000Z

366

Electrical Characterization of Cu Composition Effects in CdS/CdTe Thin-Film Solar Cells with a ZnTe:Cu Back Contact: Preprint  

DOE Green Energy (OSTI)

We study the effects of Cu composition on the CdTe/ZnTe:Cu back contact and the bulk CdTe. For the back contact, its potential barrier decreases with Cu concentration while its saturation current density increases. For the bulk CdTe, the hole density increases with Cu concentration. We identify a Cu-related deep level at {approx}0.55 eV whose concentration is significant when the Cu concentration is high. The device performance, which initially increases with Cu concentration then decreases, reflects the interplay between the positive influences and negative influences (increasing deep levels in CdTe) of Cu.

Li, J. V.; Duenow, J. N.; Kuciauskas, D.; Kanevce, A.; Dhere, R. G.; Young, M. R.; Levi, D. H.

2012-07-01T23:59:59.000Z

367

SiO{sub 2} nanospheres with tailorable interiors by directly controlling Zn{sup 2+} and NH{sub 3}.H{sub 2}O species in an emulsion process  

Science Conference Proceedings (OSTI)

SiO{sub 2} nanospheres with tailorable interiors were synthesized by a facile one-spot microemulsion process using TEOS as silica source, wherein cyclohexane including triton X-100 and n-octanol as oil phase and Zn{sup 2+} or NH{sub 3}.H{sub 2}O aqueous solution as dispersive phase, respectively. The products were characterized by Scanning Electron Microscopy, Transmission Electron Microscopy and X-ray Powder Diffraction. It was suggested that the as-synthesized silica nanospheres possessed grape-stone-like porous or single hollow interior, and also found that the ammonia dosage and aging time played key roles in controlling the size and structure of silica nanospheres. Furthermore, the comparative results confirmed that in-situ zinc species [ZnO/Zn(OH){sub 2}] acted as the temporary templates to construct grape-stone-like interior, and a simultaneously competing etching process occurred owing to the soluble Zn(NH{sub 3}){sub 4}{sup 2+} complex formation while the additional excessive ammonia was introduced. With the aging time being extended, the in-situ nanocrystals tended to grow into bigger ones by Ostwald Ripening, producing single hollow interior. - Graphical Abstract: Formation process of SiO{sub 2} nanospheres with porous and single hollow interior. Highlights: > ZnO/Zn(OH){sub 2} nanocrystals as the temporary templates shape the interior structures of SiO{sub 2} nanospheres. > Fabrication of porous and single hollow interiors needs no additional processes such as roasting or dissolving. > Tailorable interiors can be easily obtained through adjusting the aging time of temporary templates.

Liao Yuchao [State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Wu Xiaofeng [State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Wang Zhen [State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Chen Yunfa, E-mail: yfchen@home.ipe.ac.cn [State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China)

2011-07-15T23:59:59.000Z

368

Radiation dose reduction using a CdZnTe-based computed tomography system: Comparison to flat-panel detectors  

Science Conference Proceedings (OSTI)

Purpose: Although x-ray projection mammography has been very effective in early detection of breast cancer, its utility is reduced in the detection of small lesions that are occult or in dense breasts. One drawback is that the inherent superposition of parenchymal structures makes visualization of small lesions difficult. Breast computed tomography using flat-panel detectors has been developed to address this limitation by producing three-dimensional data while at the same time providing more comfort to the patients by eliminating breast compression. Flat panels are charge integrating detectors and therefore lack energy resolution capability. Recent advances in solid state semiconductor x-ray detector materials and associated electronics allow the investigation of x-ray imaging systems that use a photon counting and energy discriminating detector, which is the subject of this article. Methods: A small field-of-view computed tomography (CT) system that uses CdZnTe (CZT) photon counting detector was compared to one that uses a flat-panel detector for different imaging tasks in breast imaging. The benefits afforded by the CZT detector in the energy weighting modes were investigated. Two types of energy weighting methods were studied: Projection based and image based. Simulation and phantom studies were performed with a 2.5 cm polymethyl methacrylate (PMMA) cylinder filled with iodine and calcium contrast objects. Simulation was also performed on a 10 cm breast specimen. Results: The contrast-to-noise ratio improvements as compared to flat-panel detectors were 1.30 and 1.28 (projection based) and 1.35 and 1.25 (image based) for iodine over PMMA and hydroxylapatite over PMMA, respectively. Corresponding simulation values were 1.81 and 1.48 (projection based) and 1.85 and 1.48 (image based). Dose reductions using the CZT detector were 52.05% and 49.45% for iodine and hydroxyapatite imaging, respectively. Image-based weighting was also found to have the least beam hardening effect. Conclusions: The results showed that a CT system using an energy resolving detector reduces the dose to the patient while maintaining image quality for various breast imaging tasks.

Le, Huy Q.; Ducote, Justin L.; Molloi, Sabee [Department of Radiological Sciences, University of California, Irvine, California 92697 (United States)

2010-03-15T23:59:59.000Z

369

A Large-scale Relativistic Configuration-interaction Approach: Application to the 4s2 - 4s4p Transition Energies and E1 Rates for Zn-like Ions  

SciTech Connect

Relativistic configuration-interaction calculations of the 4s4p excitation energies and 4s{sup 2} - 4s4p E1 transitions for Zn-like ions from Z = 30 to 92 are shown. B-spline basis functions are used for these large-scale calculations. QED corrections to the excitation energies are also calculated. Results are in good agreement with other theories and with experiment, and demonstrate the utility of this method for high-precision atomic structure calculations not just for few-electron systems but also for large atomic systems such as Zn-like ions along the entire isoelectronic sequence.

Chen, M H; Cheng, K T

2009-08-28T23:59:59.000Z

370

Thickness Effect of Al-Doped ZnO Window Layer on Damp-Heat Stability of CuInGaSe2 Solar Cells  

DOE Green Energy (OSTI)

We investigated the damp heat (DH) stability of CuInGaSe{sub 2} (CIGS) solar cells as a function of thickness of the Al-doped ZnO (AZO) window layer from the 'standard' 0.12 {micro}m to a modest 0.50 {micro}m over an underlying 0.10-{micro}m intrinsic ZnO buffer layer. The CIGS cells were prepared with external electrical contact using fine Au wire to the tiny 'standard' Ni/Al (0.05 {micro}m/3 {micro}m) metal grid contact pads. Bare cell coupons and sample sets encapsulated in a specially designed, Al-frame test structure with an opening for moisture ingress control using a TPT backsheet were exposed to DH at 85 C and 85% relative humidity, and characterized by current-voltage (I-V), quantum efficiency (QE), and (electrochemical) impedance spectroscopy (ECIS). The results show that bare cells exhibited rapid degradation within 50-100 h, accompanied by film wrinkling and delamination and corrosion of Mo and AlNi grid, regardless of AZO thickness. In contrast, the encapsulated cells did not show film wrinkling, delamination, and Mo corrosion after 168 h DH exposure; but the trend of efficiency degradation rate showed a weak correlation to the AZO thickness.

Pern, F. J.; Mansfield, L.; DeHart, C.; Glick, S. H.; Yan, F.; Noufi, R.

2011-01-01T23:59:59.000Z

371

Cycle-life improvement of Zn/NiOOH cells by the addition of Ca(OH) sub 2 to the zinc electrode  

DOE Green Energy (OSTI)

The addition of Ca(OH){sub 2} to the zinc electrode of Zn/NiOOH cells was investigated in order to determine its effect on reducing the rate of Zinc redistribution. Cells containing 0, 10, 25, and 40 mol% Ca(OH){sub 2} in the zinc electrode were constructed and tested. Ca(OH){sub 2} was found to form a calcium zincate complex with the zincate-supersaturated KOH solution created during the discharge half-cycle. As Ca(OH){sub 2} is insoluble in the electrolyte, the formation of this complex (containing two Zn atoms to one Ca) significantly reduces the Zinc redistribution rate. Electrodes with only 10% Ca(OH){sub 2} were found to contain insufficient Ca(OH){sub 2} to complex with enough Zinc to make a dramatic improvement on cycle life. The 25%-Ca(OH){sub 2} electrodes, however, were found to retain their capacity beyond 150 deep discharge cycles, with indication that further Zinc redistribution would occur very slowly. The Zinc utilization of the Ca-containing electrodes showed dramatic improvement over the Ca-free zinc electrodes. 23 refs., 49 figs., 7 tabs.

Jain, R.; McLarnon, F.R.; Cairns, E.J.

1989-08-01T23:59:59.000Z

372

Low-temperature photoluminescence of detector grade Cd{sub 1{minus}{ital x}}Zn{sub {ital x}}Te crystal treated by different chemical etchants  

SciTech Connect

Low-temperature photoluminescence (PL) spectra of detector grade Cd{sub 1{minus}{ital x}}Zn{sub {ital x}}Te ({ital x}=0.1) have been measured to obtain information about shallow level defect concentration introduced during mechanical polishing and chemical etching processes. We present here a comparative PL study of Cd{sub 0.9}Zn{sub 0.1}Te crystals treated by different chemical solutions used for nuclear detector surface treatment. The results show that the 5{percent} Br{endash}MeOH+2{percent}Br{endash}20{percent} lactic acid in ethylene glycol treatment combines the advantages of bromine and lactic acid for chemical etching and results in the best surface condition, as evidenced by the largest {ital I}({ital D}{sup 0},{ital X})/{ital I}{sub def} intensity ratio and the narrowest full width at half-maximum of the main peak ({ital D}{sup 0},{ital X}). Changes in the surface morphology were also analyzed by atomic force microscopy and correlated with the PL results. Current{endash}voltage ({ital I}{endash}{ital V}) curves and the room-temperature {sup 55}Fe spectral response of the sample etched by the best treatment are also presented and discussed. {copyright} {ital 1996 American Institute of Physics.}

Chen, H.; Tong, J.; Hu, Z.; Shi, D.T.; Wu, G.H.; Chen, K.; George, M.A.; Collins, W.E.; Burger, A. [Center for Photonic Materials and Devices, Department of Physics, Fisk University, Nashville, Tennessee 37208 (United States); James, R.B. [Advanced Electronics Manufacturing Technologies Department, Sandia National Laboratories, Livermore, California 94550 (United States); Stahle, C.M. [NASA/Goddard Space Flight Center/OSC, Greenbelt, Maryland 20771 (United States); Bartlett, L.M. [NASA/Goddard Space Flight Center/NRC, Greenbelt, Maryland 20771 (United States)

1996-09-01T23:59:59.000Z

373

Spectral Optical Properties of Cu2ZnSnS4 Thin Film Between 0.73 and 6.5 eV  

Science Conference Proceedings (OSTI)

A polycrystalline Cu{sub 2}ZnSnS{sub 4} thin film was deposited on fused quartz by co-evaporation. The selected thickness was {approx}100 nm to avoid artifacts in its optical properties caused by thicker as-grown films. The composition and phase of the film were checked with x-ray fluorescence, Raman shift spectroscopy, scanning transmission electron microscopy, and energy dispersive x-ray spectroscopy. An improved spectroscopic ellipsometry methodology with two-side measurement geometries was applied to extract the complex dielectric function {var_epsilon} = {var_epsilon}{sub 1} + i{var_epsilon}{sub 2} of the Cu{sub 2}ZnSnS{sub 4} thin film between 0.73 and 6.5 eV. Five critical points were observed, at 1.32 (fundamental band gap), 2.92, 3.92, 4.96, and 5.62 eV, respectively. The {var_epsilon} spectra are in reasonable agreement with those from theoretical calculations.

Li, J.; Du, H.; Yarbrough, J.; Norman, A.; Jones, K.; Teeter, G.; Terry, F. L.; Levi, D.

2012-03-12T23:59:59.000Z

374

Thickness Effect of Al-Doped ZnO Window Layer on Damp Heat Stability of CuInGaSe2 Solar Cells: Preprint  

DOE Green Energy (OSTI)

We investigated the damp heat (DH) stability of CuInGaSe2 (CIGS) solar cells as a function of thickness of the Al-doped ZnO (AZO) window layer from the 'standard' 0.12 ?m to a modest 0.50 ?m over an underlying 0.10-?m intrinsic ZnO buffer layer. The CIGS cells were prepared with external electrical contact using fine Au wire to the tiny 'standard' Ni/Al (0.05 ?m/3 ?m) metal grid contact pads. Bare cell coupons and sample sets encapsulated in a specially designed, Al-frame test structure with an opening for moisture ingress control using a TPT backsheet were exposed to DH at 85oC and 85% relative humidity, and characterized by current-voltage (I-V), quantum efficiency (QE), and (electrochemical) impedance spectroscopy (ECIS). The results show that bare cells exhibited rapid degradation within 50-100 h, accompanied by film wrinkling and delamination and corrosion of Mo and AlNi grid, regardless of AZO thickness. In contrast, the encapsulated cells did not show film wrinkling, delamination, and Mo corrosion after 168 h DH exposure; but the trend of efficiency degradation rate showed a weak correlation to the AZO thickness.

Pern, F. J.; Mansfield, L.; DeHart, C.; Glick, S. H.; Yan, F.; Noufi, R.

2011-07-01T23:59:59.000Z

375

The interaction of 193-nm excimer laser radiation with single-crystal zinc oxide: The generation of atomic Zn line emission at laser fluences below breakdown  

SciTech Connect

The production of gas phase atomic and ionic line spectra accompanying the high laser fluence irradiation of solid surfaces is well known and is most often due to the production and interaction of high densities of atoms, ions, and electrons generated from laser-induced breakdown. The resulting plasma expands and moves rapidly away from the irradiated spot and is accompanied by intense emission of light. This type of plume is well studied and is frequently exploited in the technique of chemical analysis known as laser induced breakdown spectroscopy. Here, we describe a similar but weaker emission of light generated in vacuum by the laser irradiation of single crystal ZnO at fluences well below breakdown; this emission consists entirely of optical line emission from excited atomic Zn. We compare the properties of the resulting laser-generated gas-phase light emission (above and below breakdown) and describe a mechanism for the production of the low-fluence optical emission resulting from a fortuitous choice of material and laser wavelength.

Kahn, E. H. [Washington State University, Pullman; Langford, S. C. [Washington State University, Pullman; Dickinson, J. T. [Washington State University, Pullman; Boatner, Lynn A [ORNL

2013-01-01T23:59:59.000Z

376

Biochemical Characterization of the Mycobacterium tuberculosis Ni(II) Sensor NmtR and Streptococcus pneumoniae Zn(II) Sensor AdcR  

E-Print Network (OSTI)

NmtR and AdcR belong to two structural and functional classes of transcriptional metalloregulators. The present study shows that AdcR is a novel Zn(II) dependent repressor and the first ever metalloregulator of the MarR family. In contrast, NmtR is a repressor that is inactivated by Ni(II) binding. NmtR is a member of the extensively characterized ArsR/SmtB family. Two Ni(II) ions bind to the NmtR dimer in an octahedral coordination complex with stepwise binding affinities of KNi1 = 1.2 (±0.1) x 10¹? and KNi2 = 0.7 (±0.4) x 10¹? M?¹ (pH 7.0). A glutamine scanning mutagenesis approach reveals that Asp 91, His 93, His 104 and His 107 in the [alpha]5 helix and His 3 at the extreme N-terminal contribute to KNi. In contrast residues from the C-terminal tail (H109, D114 and H116), previously implicated in NmtR binding, are characterized by near wild-type KMe and allosteric coupling free energies. However, deletion of most of the C-terminal tail to create ?111 NmtR reduce Ni(II) binding stoichiometry to one per dimer and greatly reduced Ni(II) responsiveness. H3Q and ?111 NmtR also show important perturbations in the rank order of metal responsiveness, with both different from wild-type NmtR. The use of both presumably unstructured N- and C- terminal extensions is a unique property relative to other members of the ArsR/SmtB family previously characterized and provides a distinct metal specificities profile. AdcR binds two regulatory Zn(II) ions per dimer in an unusual five coordinate geometry as determined by X-ray and electronic absorption spectroscopy. Functional characterization of single residue substitution mutants identified His 108 and His 112 in [alpha]5 helix and His 42 in [alpha]2 helix, as residues essential for allosteric activation of DNA operator binding by AdcR as revealed by fluorescence anisotropy experiments. The stability constant for the regulatory site, KZn, is sensitive to pH and range from ~10¹? M?¹ at pH 6.0 to ~10¹? M?¹ at pH 8.0. Zn(II) binds to an additional one to two pairs of ancillary sites per dimer depending on the pH. A novel feature not shared by other Zn(II) regulators is an apparent reduced metal specificity, since non-cognate metals Mn(II) and Co(II) activate AdcR to the same extent than Zn(II) does. However, each non-cognate metal binds with very low affinity (

Reyes Caballero, Hermes

2011-08-01T23:59:59.000Z

377

Kogan-ZN  

NLE Websites -- All DOE Office Websites (Extended Search)

Drop Effective Radius for Drizzling Drop Effective Radius for Drizzling Marine Stratus in Global Circulation Models Z. N. Kogan and Y. L. Kogan Cooperative Institute for Mesoscale Meteorological Studies University of Oklahoma Norman, Oklahoma Introduction The cloud drop effective radius, R e , is one of the most important parameters in calculations of cloud radiative properties. Numerous formulations of the effective radius have been developed for use in numerical models (see, e.g., review in Gultepe et al. 1996); however, to the best of our knowledge, they all were designed for non-drizzling clouds. The objective of this paper is to derive a parameterization of R e for precipitating boundary layer clouds. The R e parameterization is necessarily a function of cloud prognostic variables used in a specific numerical model. To this regard, we note that the majority of

378

The effect of doping on global lattice properties of magnetite Fe{sub 3-x}Me{sub x}O{sub 4} (Me=Zn, Ti and Al)  

Science Conference Proceedings (OSTI)

X-ray powder diffraction was measured in Fe{sub 3-x}Me{sub x}O{sub 4} (Me=Zn, Ti, Al; x<0.065), in T range 70-300 K to see the effect of different doping on global lattice properties. The experimental results have shown that some lattice properties (e.g., the cell volume) are dopand specific. This can be attributed to the difference in preferential sites occupation by dopants. As confirmed by EXAFS, Zn enters tetrahedral, while Ti octahedral lattice sites, differently affecting crucial octahedral iron positions in the spinel lattice. However, despite this fact, it was found that T dependence of both monoclinic angle and lattice parameters is universal for studied samples above and below the Verwey transition temperature T{sub V}. So, not the iron atoms in octahedral positions individually, but interactions between them are responsible for the Verwey transition character change with doping. - Graphical abstract: A low temperature magnetite cell volume vs. dopants content. Apparently, Zn, Ti and Al atoms have different effect on the global lattice properties at individual temperatures. However, the Verwey transition reacts to dopants in a similar manner, despite the different way the octahedral iron positions are affected. Highlights: Black-Right-Pointing-Pointer We measure powder diffraction and EXAFS on Fe{sub 3-x}Me{sub x}O{sub 4}, Me=Zn, Ti, Al (x<0.065), in T range 70-300 K. Black-Right-Pointing-Pointer XRD: atom-type independent changes of lattice parameters with T. Black-Right-Pointing-Pointer EXAFS: Zn replaces Fe on tetrahedral positions, Ti on octahedral positions. Black-Right-Pointing-Pointer Thus, some secondary interactions between ordering orbitals, not the primary one driving the Verwey transition, control the transition order.

Kakol, Z. [AGH - University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30-059 Krakow (Poland); Owoc, D. [University of Agriculture, Department of Forest Work Mechanization, al. Mickiewicza 21, 31-120 Krakow (Poland); Przewoznik, J.; Sikora, M.; Kapusta, C. [AGH - University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30-059 Krakow (Poland); Zajac, D. [HASYLAB at DESY, Notkestrasse 85, Hamburg (Germany); Kozlowski, A., E-mail: kozlow@agh.edu.pl [AGH - University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30-059 Krakow (Poland); Sabol, J.E. [Chemical Consultant, Racine WI (United States); Honig, J.M. [Dept. of Chemistry, Purdue University, West Lafayette, IN (United States)

2012-08-15T23:59:59.000Z

379

Post-spinel transformations and equation of state in ZnGa[subscript 2]O[subscript 4]: Determination at high pressure by in situ x-ray diffraction  

Science Conference Proceedings (OSTI)

Room-temperature angle-dispersive x-ray diffraction measurements on spinel ZnGa{sub 2}O{sub 4} up to 56 GPa show evidence of two structural phase transformations. At 31.2 GPa, ZnGa{sub 2}O{sub 4} undergoes a transition from the cubic spinel structure to a tetragonal spinel structure similar to that of ZnMn{sub 2}O{sub 4}. At 55 GPa, a second transition to the orthorhombic marokite structure (CaMn{sub 2}O{sub 4}-type) takes place. The equation of state of cubic spinel ZnGa{sub 2}O{sub 4} is determined: V{sub 0} = 580.1(9) {angstrom}{sup 3}, B{sub 0} = 233(8) GPa, B'{sub 0} = 8.3(4), and B''{sub 0} = -0.1145 GPa{sup -1} (implied value); showing that ZnGa{sub 2}O{sub 4} is one of the less compressible spinels studied to date. For the tetragonal structure an equation of state is also determined: V{sub 0} = 287.8(9) {angstrom}{sup 3}, B{sub 0} = 257(11) GPa, B'{sub 0} = 7.5(6), and B''{sub 0} = -0.0764 GPa{sup -1} (implied value). The reported structural sequence coincides with that found in NiMn{sub 2}O{sub 4} and MgMn{sub 2}O{sub 4}.

Errandonea, D.; Kumar, Ravhi S.; Manjón, F.J.; Ursaki, V.V.; Rusu, E.V.; (UNLV); (Acad.Sci.-Moldova); (Valencia)

2009-01-15T23:59:59.000Z

380

Static magnetic response of clusters in Co_{0.2}Zn_{0.8}Fe_{1.95}Ho_{0.05}O_{4} spinel oxide  

E-Print Network (OSTI)

Earlier investigation of Co_{0.2}Zn_{0.8}Fe_{1.95}Ho_{0.05}O_{4} spinel has shown the existence of "super-ferromagnetic " clusters containing Fe^{3+} and Ho^{3+} ions along with small size clusters of Fe^{3+} ions (Bhowmik et al, J. Magn. Magn. Mater. {247}, 83 (2002)). Here, We report the static magnetic response of these clusters. The experimental data suggests some interesting magnetic features, such as, enhancement of magnetization; re-entrant magnetic transitions with paramagnetic to ferromagnetic state below 225 K and ferromagnetic to spin glass state below 120 K; appearance of field induced ferromagnetism. We also observe an unusual maximum in the thermoremanent magnetization (TRM) vs temperature data. Our measurements suggest that this unusuality in TRM is related to the blocking of "super-ferromagnetic" clusters ,out of the ferromagnetic state, along their local anisotropy axis.

R. N. Bhowmik; R. Ranganathan; R. Nagarajan

2003-06-25T23:59:59.000Z

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381

Cu/sub x/S-(Cd,Zn)S photovoltaic solar energy converters. Quarterly report No. 2, July--September 1977  

DOE Green Energy (OSTI)

Reproducible growth of uncracked, >10 ..mu..m thick films of (Cd,Zn)S has been accomplished on the As(antis 111) face of GaAs substrates and on substrates tilted approximately 14/sup 0/ off of (antis 111). Modifications to the hot wall deposition apparatus have been made to eliminate the trace impurities which had been sometimes found at the perimeter of the films. Techniques for transmission electron microscope specimen preparation have been developed. The initial TEM results have yielded evidence supporting the earlier proposed mechanism of Ga-face film cracking by an interfacial layer of GaS. The spectral response portion of the new device measurement apparatus is operational. The elastic tunneling calculations have been found to agree with experimental results reported by other workers for I-V characteristics of illuminated cells.

Peterson, T. M.; Chin, B. L.; Seshan, K.; Washburn, J.

1977-11-01T23:59:59.000Z

382

Thermal analysis, spectral characterization and refractive index studies of lithium doped PbO-ZnO-B{sub 2}O{sub 3} glass  

SciTech Connect

Lithium containing lead zinc borate glasseshave been prepared by melt quenching technique. X-ray diffraction reveals the amorphous nature of the glass. Differential scanning calorimeter (DSC) study was carried out in the temperature range RT to 600 deg. C temperature and found glass transition temperature of these glasses decreases with increase in inter substitution of Pb and Zn lithium content. PZB glasses are stable, IR spectra of these glasses show characteristics band originating from borate groups namely [BO{sub 3}] [BO{sub 4}]and B-O-B stretching vibrations respectively, and found that structure is not affected with effect of lithium content. Refractive index of these glasses are in the range of 1.47 with increasing lithium content refractive index decreases indicating decrease in scattering of light.

Rajaramakrishna, R.; Lakshmikantha, R.; Anavekar, R. V. [Department of Physics, Bangalore University, Jnanabarthi campus, Bangalore - 560056 (India); Department of Physics, K.L.E.Society's S. N. College, Bangalore - 560 010 (India); Department of Physics, Bangalore University, Jnanabarthi campus, Bangalore - 560056 (India)

2012-06-05T23:59:59.000Z

383

Synchrotron radiation based cross-sectional scanning photoelectron microscopy and spectroscopy of n-ZnO:Al/p-GaN:Mg heterojunction  

Science Conference Proceedings (OSTI)

Al-doped ZnO (AZO) deposited by radio frequency co-sputtering is formed on epitaxial Mg-doped GaN template at room temperature to achieve n-AZO/p-GaN heterojunction. Alignment of AZO and GaN bands is investigated using synchrotron radiation based cross-sectional scanning photoelectron microscopy and spectroscopy on the nonpolar side-facet of a vertically c-axis aligned heterostructure. It shows type-II band configuration with valence band offset of 1.63 {+-} 0.1 eV and conduction band offset of 1.61 {+-} 0.1 eV, respectively. Rectification behavior is clearly observed, with a ratio of forward-to-reverse current up to six orders of magnitude when the bias is applied across the p-n junction.

Lee, Kai-Hsuan; Chen, Chia-Hao [Nano Science Group, National Synchrotron Radiation Research Center, Hsin-Ann Rd. 101, 30076 Hsinchu, Taiwan (China)] [Nano Science Group, National Synchrotron Radiation Research Center, Hsin-Ann Rd. 101, 30076 Hsinchu, Taiwan (China); Chang, Ping-Chuan [Department of Electro-Optical Engineering, Kun Shan University, Dawan Rd. 949, 71003 Tainan, Taiwan (China)] [Department of Electro-Optical Engineering, Kun Shan University, Dawan Rd. 949, 71003 Tainan, Taiwan (China); Chen, Tse-Pu; Chang, Sheng-Po; Chang, Shoou-Jinn [Institute of Microelectronics and Department of Electrical Engineering, Center for Micro/Nano Science and Technology, Advanced Optoelectronic Technology Center, National Cheng Kung University, University Rd. 1, 70101 Tainan, Taiwan (China)] [Institute of Microelectronics and Department of Electrical Engineering, Center for Micro/Nano Science and Technology, Advanced Optoelectronic Technology Center, National Cheng Kung University, University Rd. 1, 70101 Tainan, Taiwan (China); Shiu, Hung-Wei; Chang, Lo-Yueh [Nano Science Group, National Synchrotron Radiation Research Center, Hsin-Ann Rd. 101, 30076 Hsinchu, Taiwan (China) [Nano Science Group, National Synchrotron Radiation Research Center, Hsin-Ann Rd. 101, 30076 Hsinchu, Taiwan (China); Department of Physics, National Tsing Hua University, Kuang-Fu Rd. 101, 30013 Hsinchu, Taiwan (China)

2013-02-18T23:59:59.000Z

384

Fabrication and characterization of GaSb based thermophotovoltaic cells using Zn diffusion from a doped spin-on glass source  

DOE Green Energy (OSTI)

The GaInSb material system is attractive for application in thermophotovoltaic (TPV) cells since its band gap can be tuned to match the radiation of the emitter. At present, most of the TPV cells are fabricated using epitaxial layers and hence are expensive. To reduce the cost, Zn diffusion using elemental vapors in a semi-closed diffusion system is being pursued by several laboratories. In this paper, the authors present studies carried out on Zn diffusion into n-type (Te-doped) GaSb substrates in an open tube diffusion furnace. The dopant precursor was a 2,000 {angstrom} thick, zinc doped spin-on glass. The diffusion was carried out at temperatures ranging from 550 to 600 C, for times from 1 to 10 hours. The diffused layers were characterized by Hall measurements using step-and-repeat etching by anodic oxidation, secondary ion mass spectrometry (SIMS) measurements and TPV device fabrication. For diffusion carried out at 600 C, the junction depth was 0.3 {micro}m, and the hole concentration near the surface was 5 {times} 10{sup 19}/cm{sup 3}. The external quantum efficiency, measured without any anti-reflection coating, of the TPV cells fabricated using mesa-etching had a maximum value of 38%. Masked diffusion was also carried out by opening windows in a Si{sub 3}N{sub 4} coated, GaSb wafer. TPV cells fabricated on these structures had similar quantum efficiency, but lower dark current.

Dakshinamurthy, S.; Shetty, S.; Bhat, I.; Hitchcock, C.; Gutmann, R. [Rensselaer Polytechnic Inst., Troy, NY (United States); Charache, G.; Freeman, M. [Lockheed Martin Corp., Schenectady, NY (United States)

1998-06-01T23:59:59.000Z

385

Percolation and excitonic luminescence in SiO{sub 2}/ZnO two-phase structures with a high density of quantum dots randomly distributed over a spherical surface  

Science Conference Proceedings (OSTI)

The results of studies of structures formed of silica (SiO{sub 2}) nanospheres and ZnO quantum dots randomly distributed over the nanosphere surface to cover an {approx}0.45 fraction of the surface area are given. Because of the large surface energy of the spheres, the quantum dots formed on their surface are shaped as disks, wherein charge carriers are influenced by the quantum-confinement effect despite the large disk radii. The disk height is calculated by the effective mass method. The height is found to be comparable with the diameter of excitons in bulk ZnO. Analysis of the optical spectra shows that, at the above-indicated surface area covered with quantum dots, excitons in the array of quantum dots are above the percolation level. The use of some concepts of the percolation theory and knowledge of the topological arrangement of the samples make it possible to obtain quantitative parameters that describe this phenomenon.

Bondar, N. V., E-mail: jbond@iop.kiev.ua [National Academy of Sciences of Ukraine, Institute of Physics (Ukraine)

2011-04-15T23:59:59.000Z

386

Effect of pH treatment on K-shell x-ray intensity ratios and K-shell x-ray-production cross sections in ZnCo alloys  

Science Conference Proceedings (OSTI)

In this study, empirical and semiempirical K-shell fluorescence yields ({omega}{sub K}) and K{beta}/K{alpha} intensity ratios from the available experimental data for elements with 23{241}Am annular radioactive source. K x rays emitted by samples were counted by an Ultra-LEGe detector with a resolution of 150 eV at 5.9 keV. The effect of pH values on alloy compositions and the effect of alloying on the fluorescence parameters of Co and Zn were investigated. The x-ray fluorescence parameters of Co and Zn in the alloying system indicate significant differences with respect to the pure metals. These differences are attributed to the reorganization of valence shell electrons and/or charge transfer phenomena.

Kup Aylikci, N.; Aylikci, V.; Tirasoglu, E.; Cengiz, E. [Department of Physics, Faculty of Sciences, Karadeniz Technical University, TR-61080 Trabzon (Turkey); Kahoul, A. [Bordj-Bou-Arreridj University Center, Institute of Science and Technology, 34000 (Algeria); Physics Department, Laboratory LESIMS, Ferhat Abbas University, Faculty of Science, 19000 Setif (Algeria); Karahan, I. H. [Department of Physics, Faculty of Arts and Sciences, Mustafa Kemal University, TR-31040 Hatay (Turkey)

2011-10-15T23:59:59.000Z

387

Chemical stability and dielectric properties of RO-La{sub 2}O{sub 3}-B{sub 2}O{sub 3} (R = Ca, Mg, Zn)-based ceramics  

SciTech Connect

New lanthanum borate (La{sub 2}O{sub 3}-B{sub 2}O{sub 3}) glasses modified with divalent oxides, such as CaO, MgO and ZnO were investigated as potential low temperature dielectrics by understanding compositional dependence of dielectric properties and chemical leaching resistance. Firing behavior, such as densification and crystallization, depended strongly on the glass composition and is found to influence the resultant dielectric performance. Specifically, the dielectric composition of 20ZnO-20La{sub 2}O{sub 3}-60B{sub 2}O{sub 3} glass with 40 wt% Al{sub 2}O{sub 3} as a filler showed distinct enhancements of dielectric properties, i.e., k {approx} 8.3 and Q {approx} 1091 at the resonant frequency of 17.1 GHz, as a result of 850 deg. C firing. The result was believed related to earlier densification and unexpected evolvements of ZnAl{sub 2}O{sub 4} and La(BO{sub 2}){sub 3} phases during firing. The Mg-containing glass sample was most stable in strong acid solutions and did not show any significant changes in microstructure even after 300 min exposure. The Ca-containing glass sample was not regarded as a promising candidate for low temperature dielectrics from the observed low quality factor and weak chemical durability.

Jo, Yeon Hwa [Department of Materials Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Kang, Min Soo; Chung, Kyung Won [DAION Co., Ltd., Incheon 405-846 (Korea, Republic of); Cho, Yong Soo [Department of Materials Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of)], E-mail: yongscho@yonsei.ac.kr

2008-02-05T23:59:59.000Z

388

Regulation of motility, the cell cycle, and magnetosome formation in Magnetospirillum magneticum AMB-1  

E-Print Network (OSTI)

r epair enzyme hypot het ical pr ot ein Nif Q pr ot ein f erhypot het ical pr ot ein Nif X pr ot ein nit r ogenasexU-like pr ot ein put at ive nif Z pr ot ein hypot het ical

Greene, Shannon Elizabeth

2012-01-01T23:59:59.000Z

389

Probing the electrostatic potential of charged dislocations in n-GaN and n-ZnO epilayers by transmission electron holography  

SciTech Connect

Epitaxial layers frequently contain a high density of threading dislocations, which may exceed values of 10{sup 9} cm{sup -2} for ZnO and GaN. To study the electrical activity of single dislocations off-axis electron holography in a transmission electron microscope was applied. The electrostatic potential in the vicinity of charged dislocations was determined from the reconstructed phase of the electron wave, which also provides access to the charge density at the dislocation. On the basis of the electrostatic potential for a screened line charge given by Read [Philos. Mag. 45, 775 (1954)] a refined model is proposed in which a charge density with a finite spatial distribution at the dislocation core is assumed. Comparing the measured and theoretically expected potential, charge densities between 5x10{sup 19} cm{sup -3} and 5x10{sup 20} cm{sup -3} in cylinders with radii up to 5 nm around the dislocation lines were found. An important aspect of our work is the analysis of dislocations in cross-section transmission electron microscopy samples where the dislocation lines are oriented perpendicular to the electron beam. The advantages and drawbacks of the cross-section geometry are discussed. Electrostatic potentials due to piezoelectric charges in the dislocation strain field are considered and found to be insignificant with respect to dislocation charges.

Mueller, E.; Gerthsen, D.; Brueckner, P.; Scholz, F.; Gruber, Th.; Waag, A. [Laboratorium fuer Elektronenmikroskopie, Universitaet Karlsruhe (Thailand) 76128 Karlsruhe (Germany); Abteilung Optoelektronik, Universitaet Ulm, D-89069 Ulm (Germany); Abteilung Halbleiterphysik, Universitaet Ulm, D-89069 Ulm (Germany); Institut fuer Halbleitertechnik, Universitaet Braunschweig, D-38106 Braunschweig (Germany)

2006-06-15T23:59:59.000Z

390

Photophysical Studies of Ru(II)tris(2,2;#8242;-bipyridine) Confined within a Zn(II)?Trimesic Acid Polyhedral Metal?Organic Framework  

Science Conference Proceedings (OSTI)

The ability to confine photoactive catalysts within metal-organic framework (MOF) materials affords the opportunity to expand the functional diversity of these materials into solar based applications. Here, the confinement of Ru(II)tris(2,2'-bipyridine) (RuBpy) by a MOF material derived from Zn(II) ions and trimesic acid (hereafter, USF2) is examined. Although the encapsulated RuBpy could not be crystallographically resolved within the MOF framework, the photophysical properties of the complex are characteristic of confinement including extended triplet metal-to-ligand ({sup 3}MLCT) lifetime ({tau}{sub ethanol} = 614 ns and {tau}{sub USF2} = 1.2 {micro}s at 25 C) and a slight hypsochromic shift in the steady-state emission spectrum relative to RuBpy in ethanol. The extended lifetime is attributed to a deactivation of a nonradiative {sup 3}dd that is antibonding with respect to the Ru(II)-bipyridine due to a confined molecular environment. These results represent one of the first examples of RuBpy encapsulation and photophysical characterization within a polyhedral MOF material.

Larsen, Randy W.; Wojtas, Lukasz (USF)

2012-10-25T23:59:59.000Z

391

Effect of (Bi, La)(Fe, Zn)O{sub 3} thickness on the microstructure and multiferroic properties of BiFeO{sub 3} thin films  

Science Conference Proceedings (OSTI)

The effect of Bi{sub 0.90}La{sub 0.10}Fe{sub 0.90}Zn{sub 0.10}O{sub 3} (BLFZO) thicknesses on the microstructure and multiferroic properties of BiFeO{sub 3} (BFO) thin films was investigated, and all bilayered thin films were grown on Pt-coated silicon substrates without any buffer layers by a radio frequency sputtering. A (110) orientation is dominant in all the bilayers, and two grain growth modes are identified in these bilayers by using an atomic force microscope, where different grain growth modes significantly affect their leakage behavior. The dielectric constant ({epsilon}{sub r}) of bilayers gradually increases, and magnetic properties were deteriorated with the addition of BLFZO with a higher {epsilon}{sub r} and a weaker magnetic behavior. An enhanced ferroelectric behavior of 2P{sub r} {approx} 116.2 {mu}C/cm{sup 2} and 2E{sub c} {approx} 524 kV/cm could be observed in the BFO/BLFZO bilayered thin film with 80 nm BLFZO layer owing to a higher orientation degree of (110) and an interface coupling together with a lower leakage current density. As a result, electrical properties of BFO could be tailored by modifying the thicknesses of BLFZO.

Wu Jiagang; Xiao Dingquan; Zhu Jianguo [Department of Materials Science, Sichuan University, Chengdu 610064 (China)

2012-11-01T23:59:59.000Z

392

Room temperature metathetic synthesis and characterization of {alpha}-hopeite, Zn{sub 3}(PO{sub 4}){sub 2}.4H{sub 2}O  

SciTech Connect

The synthesis of crystalline zinc phosphates ({alpha}-hopeite phase) through the metathetic pathway has been investigated. The reaction has been carried out by room-temperature grinding. High lattice energy of the by-product NaCl has driven the reaction in the forward direction, and as a result, stable phosphate phases have been synthesized. Reaction of a different phosphorus source (like Na{sub 3}PO{sub 4}, Na{sub 2}HPO{sub 4}, NaH{sub 2}PO{sub 4}, and K{sub 2}HPO{sub 4}) with ZnCl{sub 2} has been attempted. The structural, vibrational, thermal, optical, and chemical properties of synthesized powders are determined by powder X-ray diffraction (XRD), scanning electron microscope (SEM), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and diffused reflectance spectra (DR) in the UV-vis range. The direct band gap of the title compound was determined to be 3.6 {+-} 0.2 eV.

Parhi, Purnendu [Department of Mechanical Engineering, Colorado State University, Fort Collins, CO 80523 (United States); Manivannan, V. [Department of Mechanical Engineering, Colorado State University, Fort Collins, CO 80523 (United States)], E-mail: mani@engr.colostate.edu; Kohli, Sandeep; McCurdy, Patrick [Department of Chemistry, Colorado State University, Fort Collins, CO 80523 (United States)

2008-07-01T23:59:59.000Z

393

Drift time variations in CdZnTe detectors measured with alpha-particles: Their correlation with the detector’s responses  

Science Conference Proceedings (OSTI)

Homogeneity of properties related to material crystallinity is a critical parameter for achieving high-performance CdZnTe (CZT) radiation detectors. Unfortunately, this requirement is not always satisfied in today's commercial CZT material due to high concentrations of extended defects, in particular subgrain boundaries, which are believed to be part of the causes hampering the energy resolution and efficiency of CZT detectors. In the past, the effects of subgrain boundaries have been studied in Si, Ge and other semiconductors. It was demonstrated that subgrain boundaries tend to accumulate secondary phases and impurities causing inhomogeneous distributions of trapping centers. It was also demonstrated that subgrain boundaries result in local perturbations of the electric field, which affect the carrier transport and other properties of semiconductor devices. The subgrain boundaries in CZT material likely behave in a similar way, which makes them responsible for variations in the electron drift time and carrier trapping in CZT detectors. In this work, we employed the transient current technique to measure variations in the electron drift time and related the variations to the device performances and subgrain boundaries, whose presence in the crystals were confirmed with white beam X-ray diffraction topography and infrared transmission microscopy.

Bolotnikov A. E.; Butcher, J.; Hamade, M.; Petryk, M.; Bolotnikov, A.; Camarda, G.; Cui, Y.; Hossain, A.; Kim, K.; Yang, G.; and James, R.

2012-05-14T23:59:59.000Z

394

Deposition of stress free c-axis oriented LiNbO{sub 3} thin film grown on (002) ZnO coated Si substrate  

Science Conference Proceedings (OSTI)

C-axis oriented lithium niobate thin films have been deposited on Si substrate using RF sputtering technique. A thin buffer layer of c-axis (002) oriented ZnO on Si substrate has been used as a nucleating layer to promote the growth of (006) oriented LiNbO{sub 3} film. The processing gas composition and pressure are found to be very critical in obtaining stress free LiNbO{sub 3} film having desired (006) orientation. The LiNbO{sub 3} films deposited under unique combination of sputtering pressure (10 mTorr) and argon percentage (80%) in reactive gas (Ar + O{sub 2}) composition become almost stress free having lattice parameter (1.3867 A) close to the bulk value. The observed variation in the structural properties and optical phonon modes observed by Raman spectroscopic studies of the oriented LiNbO{sub 3} thin film with stress has been correlated with growth kinetics.

Shandilya, Swati; Gupta, Vinay [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Tomar, Monika [Miranda House, University of Delhi, Delhi 110007 (India)

2012-05-15T23:59:59.000Z

395

In situ X-ray absorption fine structure studies of a manganese dioxide electrode in a rechargeable MnO{sub 2}/Zn alkaline battery environment  

DOE Green Energy (OSTI)

Electronic and structural aspects of a MnO{sub 2} electrode in a rechargeable MnO{sub 2}/Zn battery environment have been investigated by in situ Mn K-edge X-ray absorption fine structure (XAFS). The relative amplitudes of the three major Fourier transform shells of the EXAFS (extended XAFS) function of the rechargeable MnO{sub 2} electrode in the undischarged state were found to be similar to those found for ramsdellite, a MnO{sub 2} polymorph with substantial corner-sharing linkages among the basic MnO{sub 6} octahedral units. The analyses of the background-subtracted pre-edge peaks and absorption edge regions for the nominally 1-e{sup {minus}} discharged electrode were consistent with Mn{sup 3+} as being the predominant constituent species, rather than a mixture of Mn{sup 4+} and Mn{sup 2+} sites. Furthermore, careful inspection of both the XANES (X-ray absorption near edge structure) and EXAFS indicated that the full recharge of MnO, which had been previously discharged either by a 1- or 2-equivalent corner-sharing linkages compared to the original undischarged MnO{sub 2}.

Mo, Y.; Hu, Y.; Bae, I.T.; Miller, B.; Scherson, D.A. [Case Western Reserve Univ., Cleveland, OH (United States). Dept. of Chemistry; Antonio, M.R. [Argonne National Lab., IL (United States). Chemistry Div.

1996-12-31T23:59:59.000Z

396

The Effects of Test Temperature, Temper, and Alloyed Copper on the Hydrogen-Controlled Crack Growth Rate of an Al-Zn-Mg-(Cu) Alloy  

DOE Green Energy (OSTI)

The hydrogen embrittlement controlled stage II crack growth rate of AA 7050 (6.09 wt.% Zn, 2.14 wt% Mg, 2.19 wt.% Cu) was investigated as a function of temper and alloyed copper level in a humid air environment at various temperatures. Three tempers representing the underaged, peak aged, and overaged conditions were tested in 90% relative humidity (RH) air at temperatures between 25 and 90 C. At all test temperatures, an increased degree of aging (from underaged to overaged) produced slower stage II crack growth rates. The stage II crack growth rate of each alloy and temper displayed Arrhenius-type temperature dependence with activation energies between 58 and 99 kJ/mol. For both the normal copper and low copper alloys, the fracture path was predominantly intergranular at all test temperatures (25-90 C) in each temper investigated. Comparison of the stage II crack growth rates for normal (2.19 wt.%) and low (0.06 wt.%) copper alloys in the peak aged and overaged tempers showed the beneficial effect of copper additions on stage II crack growth rate in humid air. In the 2.19 wt.% copper alloy, the significant decrease ({approx} 10 times at 25 C) in stage II crack growth rate upon overaging is attributed to an increase in the apparent activation energy for crack growth. IN the 0.06 wt.% copper alloy, overaging did not increase the activation energy for crack growth but did lower the pre-exponential factor, {nu}{sub 0}, resulting in a modest ({approx} 2.5 times at 25 C) decrease in crack growth rate. These results indicate that alloyed copper and thermal aging affect the kinetic factors that govern stage II crack growth rate. Overaged, copper bearing alloys are not intrinsically immune to hydrogen environment assisted cracking but are more resistant due to an increased apparent activation energy for stage II crack growth.

G.A. Young, Jr.; J.R. Scully

2000-09-17T23:59:59.000Z

397

Application of Extruded Dielectric Cable Model in the Dynamic Thermal Circuit Rating (DTCR) System for San Diego Gas & Electric's Ot ay Mesa Power Loop Project  

Science Conference Proceedings (OSTI)

Due to limited incentives for new construction, utilities around the world are undergoing a major transformation that is redefining the use of existing power equipment in the electric transmission network. Under these circumstances, utilities are forced to find new ways to increase power flow through the existing transmission corridors with minimal investments. This report addresses the application of the Electric Power Research Institute's (EPRI's) Dynamic Thermal Circuit Rating (DTCR) program to San Di...

2010-02-02T23:59:59.000Z

398

Study of structure-function relationships in proteins: Techniques and applications ot cytochrome c: Final report January 15, 1988--January 14, 1989  

SciTech Connect

During the initial period of this work we explored the differential geometry results which had been used to explain the structure-function relationships in the set of yeast iso-1-cytochrome c mutants studied under the initial contract. In addition we continued the development of techniques which would permit the structural characterization and comparison of proteins in a very efficient manner. We have expanded the studies based on the characterization of the structural preferences of various residues in a sample of twenty six globular proteins. It has been demonstrated that the overall structural preferences and the amino acid specific preferences seen in the analysis carried out at the five alpha carbon level can not be explained by the results of the analysis carried out at the four alpha carbon level. Thus the structural preferences seen must be described by considering groups of five or more residues. We do no yet have enough data to extend the analysis to the six alpha carbon unit level. We have also verified that the yeast/tuna structural analogy which we used before was justified, and have performed a conformational energy minimization of the reduced yeast cytochrome c crystal data in order to have a baseline for the study of mutant proteins. 6 refs.

Goldstein, D.A.; Rackovsky, S.R.

1989-08-01T23:59:59.000Z

399

Description of Represented Work for Selected Job Families OVERVIEW The following descriptions provide a summary of Operational & Technical (O&T) or Professional work that is  

E-Print Network (OSTI)

. Troubleshoots/monitors scheduling criteria and researches missing or delayed jobs. Updated July 2008 #12

Alvarez-Cohen, Lisa

400

J. world tlaticrrl. Soc, l4;513*623 (1983) POND CULTURE OT S'TRIPED BASS X WIIITE BASS HYBRIDS  

E-Print Network (OSTI)

of age at densities similar to those usec in culturc of channel catfish {rcta]urus Functatus}. rn view

Hamza, Iqbal

Note: This page contains sample records for the topic "zn zurn ot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Bright three-band white light generated from CdSe/ZnSe quantum dot-assisted Sr{sub 3}SiO{sub 5}:Ce{sup 3+},Li{sup +}-based white light-emitting diode with high color rendering index  

SciTech Connect

In this study, bright three-band white light was generated from the CdSe/ZnSe quantum dot (QD)-assisted Sr{sub 3}SiO{sub 5}:Ce{sup 3+},Li{sup +}-based white light-emitting diode (WLED). The CdSe/ZnSe core/shell structure was confirmed by energy dispersive x-ray spectroscopy and x-ray photoelectron spectroscopy. The CdSe/ZnSe QDs showed high quantum efficiency (79%) and contributed to the high luminous efficiency ({eta}{sub L}) of the fabricated WLED. The WLED showed bright natural white with excellent color rendering property ({eta}{sub L}=26.8 lm/W, color temperature=6140 K, and color rendering index=85) and high stability against the increase in forward bias currents from 20 to 70 mA.

Jang, Ho Seong; Kwon, Byoung-Hwa; Jeon, Duk Young [Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, 373-1, Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Yang, Heesun [Department of Materials Science and Engineering, Hongik University, 72-1, Sangsu-dong, Mapo-gu, Seoul 121-791 (Korea, Republic of)

2009-10-19T23:59:59.000Z

402

Th-Zn (Thorium - Zinc)  

Science Conference Proceedings (OSTI)

...Th (Thorium) Binary Alloy Phase Diagrams, Alloy Phase Diagrams, Vol 3, ASM Handbook, ASM International,

403

J6, ZnO/ZnTeO/ZnTe Heterojunctions for Intermediate State Solar ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, 2010 Electronic Materials Conference. Symposium, TMS 2010 Electronic Materials Conference. Presentation Title, J6 ...

404

Optical properties of a-plane (Al, Ga)N/GaN multiple quantum wells grown on strain engineered Zn{sub 1-x}Mg{sub x}O layers by molecular beam epitaxy  

Science Conference Proceedings (OSTI)

Nonpolar (1120) Al{sub 0.2}Ga{sub 0.8}N/GaN multiple quantum wells (MQWs) have been grown by molecular beam epitaxy on (1120) Zn{sub 0.74}Mg{sub 0.26}O templates on r-plane sapphire substrates. The quantum wells exhibit well-resolved photoluminescence peaks in the ultra-violet region, and no sign of quantum confined Stark effect is observed in the complete multiple quantum well series. The results agree well with flat band quantum well calculations. Furthermore, we show that the MQW structures are strongly polarized along the [0001] direction. The origin of the polarization is discussed in terms of the strain anisotropy dependence of the exciton optical oscillator strengths.

Xia, Y.; Vinter, B.; Chauveau, J.-M. [CRHEA-CNRS, Rue Bernard Gregory, 06560 Valbonne (France); University of Nice Sophia-Antipolis, 06103 Nice (France); Brault, J.; Nemoz, M.; Teisseire, M.; Leroux, M. [CRHEA-CNRS, Rue Bernard Gregory, 06560 Valbonne (France)

2011-12-26T23:59:59.000Z

405

Functional properties of BaTiO{sub 3}-Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} magnetoelectric ceramics prepared from powders with core-shell structure  

Science Conference Proceedings (OSTI)

In the present work, diphasic ceramic composites with core-shell nanostructures formed by Ni{sub 0.50}Zn{sub 0.50}Fe{sub 2}O{sub 4} core and BaTiO{sub 3} shell were investigated. Their properties were compared with those of composites prepared by coprecipitation. The core-shell structure was confirmed by microstructural powder analysis. Homogeneous microstructures with a good phase mixing and percolated dielectric phase by the magnetic one were obtained from coprecipitated powders. Less homogeneous microstructures resulted in ceramics produced from the powder prepared by core-shell method, with isolated small ferrite grains besides large ferrite aggregates embedded into the BaTiO{sub 3} matrix. Both the ferroelectric and magnetic phases preserve their basic properties in bulk composite form. However, important differences in the dielectric relaxation and conduction mechanisms were found as result of the microstructural difference. Extrinsic contributions play important roles in modifying the electric properties in both ceramics, causing space charge effect, Maxwell-Wagner relaxations and hopping conductivity, mainly due to the ferrite low resistivity phase. The conductivity and dielectric modulus spectra analysis allowed to identify different polaron contributions associated with the microstructural differences. It results that by using the core-shell method, improved dielectric properties and limited hopping contributions can be realized.

Curecheriu, L. P.; Mitoseriu, L.; Postolache, P. [Department of Physics, Al. I. Cuza University, Bv. Carol I, no. 11, Iasi 700506 (Romania); Buscaglia, M. T.; Buscaglia, V. [Institute for Energetics and Interphases, CNR, Via de Marini no. 6, Genoa I-16149 (Italy); Ianculescu, A. [Department of Oxide Materials Science and Engineering, Polytechnics University, 1-7 Gh. Polizu, P.O. Box 12-134, Bucharest 011061 (Romania); Nanni, P. [Institute for Energetics and Interphases, CNR, Via de Marini no. 6, Genoa I-16149 (Italy); Department of Chemistry and Process Engineering, University of Genoa, P-le Kennedy no. 1, Genoa (Italy)

2010-05-15T23:59:59.000Z

406

Five new Zn(II) and Cd(II) coordination polymers constructed by 3,5-bis-oxyacetate-benzoic acid: Syntheses, crystal structures, network topologies and luminescent properties  

Science Conference Proceedings (OSTI)

Five Zn(II) and Cd(II) coordination polymers, [Zn{sub 2}(BOABA)(bpp)(OH)]{center_dot}0.5H{sub 2}O (1), [Cd{sub 3}(BOABA){sub 2}(bpp){sub 2}(H{sub 2}O){sub 6}]{center_dot}2H{sub 2}O (2), [Cd{sub 3}(BOABA){sub 2}(2,2 Prime -bipy){sub 3}(H{sub 2}O){sub 4}]{center_dot}5.5H{sub 2}O (3), [CdNa(BOABA)(H{sub 2}O)]{sub 2}{center_dot}H{sub 2}O (4) and [Cd{sub 2}(BOABA)(bimb)Cl(H{sub 2}O){sub 2}]{center_dot}H{sub 2}O (5) (H{sub 3}BOABA=3,5-bis-oxyacetate-benzoic acid, bpp=1,3-bi(4-pyridyl)propane, 2,2 Prime -bipy=2,2 Prime -bipyridine, bimb=1,4-bis(imidazol-1 Prime -yl)butane), have been solvothermally synthesized and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra and TG analyses. 1 is an uninodal 4-connected 2D square grid network based on binuclear zinc clusters. 2 is 2D wavelike layer structure and further linked by hydrogen bonds into the final 3D (5,6,6)-connected topology network. 3 is 3-connected 2D topology network and the 2,2 Prime -bipy ligands decorate in two different types. 4 is a (4,8)-connected 2D topology network with heterocaryotic {l_brace}Cd{sub 2}Na{sub 2}{r_brace} clusters and BOABA{sup 3-} ligands. 5 can be rationalized as a (3,10)-connected 3D topology network with tetranuclear {l_brace}Cd{sub 4}Cl{sub 2}{r_brace} clusters and BOABA{sup 3-} ligands. Meanwhile, photoluminescence studies revealed that these five coordination polymers display strong fluorescent emission bands in the solid state at room temperature. - Graphical abstract: Five new d{sup 10} metal(II) coordination polymers based on H{sub 3}BOABA ligand were obtained and characterized. They display different topological structures and luminescent properties. Highlights: Black-Right-Pointing-Pointer Five d{sup 10} metal(II) polymers based on 3,5-bis-oxyacetate-benzoic acid were obtained. Black-Right-Pointing-Pointer The polymers were structurally characterized by single-crystal X-ray diffraction. Black-Right-Pointing-Pointer Polymers 1-5 display different topological structures. Black-Right-Pointing-Pointer They show strong fluorescent emission bands in the solid state.

Jiang Xianrong; Yuan Hongyan [Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua, Zhejiang 321004 (China); Feng Yunlong, E-mail: sky37@zjnu.edu.cn [Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua, Zhejiang 321004 (China)

2012-07-15T23:59:59.000Z

407

Polarized IR and Raman spectra of Ca{sub 2}MgSi{sub 2}O{sub 7}, Ca{sub 2}ZnSi{sub 2}O{sub 7} and Sr{sub 2}MgSi{sub 2}O{sub 7} single crystals: Temperature-dependent studies of commensurate to incommensurate and incommensurate to normal phase transitions  

Science Conference Proceedings (OSTI)

IR and Raman spectra of Ca{sub 2}MgSi{sub 2}O{sub 7}, Ca{sub 2}ZnSi{sub 2}O{sub 7} and Sr{sub 2}MgSi{sub 2}O{sub 7} oriented single crystals and powders have been measured. The temperature dependence of phonons has been established in the 4-650 K range. Discussion of the results has been performed on the basis of factor group approach for the tetragonal P4-bar 2{sub 1}m (D{sub 2d}{sup 3}) space group with Z=2. The assignment of the bands observed to the internal and external modes has been made on their polarization behaviour, phonon energy calculations and literature data. The evidences of the LO-TO splitting and commensurate (C) to incommensurate (IC) as well as incommensurate (IC) to normal (N) phase transitions have been found. As a representative example, the results obtained for the spontaneous Raman scattering have also been used in the discussion of the stimulated Raman spectra of Ca{sub 2}ZnSi{sub 2}O{sub 7}. - Graphical abstract: Raman and IR spectra of Ca{sub 2}MgSi{sub 2}O{sub 7}, Ca{sub 2}ZnSi{sub 2}O{sub 7}, Sr{sub 2}MgSi{sub 2}O{sub 7} have been measured. The temperature dependence of phonons has been established in the 4-650 K range. The evidences of the LO-TO splitting and commensurate (C) to incommensurate (IC) as well as incommensurate (IC) to normal (N) phase transitions have been found. Highlights: Black-Right-Pointing-Pointer Polarized IR and Raman spectra of pyrosilicates single crystals have been studied. Black-Right-Pointing-Pointer Temperature dependence of the phonon bands and LO-TO splitting have been analysed. Black-Right-Pointing-Pointer Commensurate to incommensurate and to normal phase have been evidenced in the spectra. Black-Right-Pointing-Pointer Phonon calculations have been used in assignment of the normal modes. Black-Right-Pointing-Pointer Stimulated Raman spectra of Ca{sub 2}ZnSi{sub 2}O{sub 7} crystal have been measured and analysed.

Hanuza, J. [Institute of Low Temperatures and Structure Research, Polish Academy of Sciences, ul. Okolna 2, Wroclaw (Poland); Department of Bioorganic Chemistry, Institute of Chemistry and Food Technology, Wroclaw University of Economics, 118/120 Komandorska str., Wroclaw (Poland); Ptak, M., E-mail: m.ptak@int.pan.wroc.pl [Institute of Low Temperatures and Structure Research, Polish Academy of Sciences, ul. Okolna 2, Wroclaw (Poland); Maczka, M.; Hermanowicz, K. [Institute of Low Temperatures and Structure Research, Polish Academy of Sciences, ul. Okolna 2, Wroclaw (Poland); Lorenc, J. [Department of Bioorganic Chemistry, Institute of Chemistry and Food Technology, Wroclaw University of Economics, 118/120 Komandorska str., Wroclaw (Poland); Kaminskii, A.A. [Institute of Crystallography, Russian Academy of Sciences, Moscow (Russian Federation)

2012-07-15T23:59:59.000Z

408

Al-Cu-Li-Mg-Zn  

Science Conference Proceedings (OSTI)

High Strength Aluminum Brazing Sheets for Condenser Fins of Automotive Heat ... for the Phase Formation in a Wide Range of Commercial Aluminum Alloys.

409

ZnO Nanowires Grown on ZnO Thin Film Deposited by Atomic Layer ...  

Science Conference Proceedings (OSTI)

In this work the atomic layer deposition (ALD) technique was used to deposit the seeding ... 3D Multiwall Carbon Nanotubes (MWCNTs) for Li-Ion Battery Anode.

410

Nanoparticulate PdZn as a Novel Catalyst for ZnO Nanowire Growth  

E-Print Network (OSTI)

the European Commission (NOE EXCELL NMP3-CT-2005-515703, Volker Engels) and the Nokia Research Centre Cambridge, UK, through the NRC/Cambridge University Framework Research Agreement Project on Large Area Sensing Surfaces (Aron Rachamim, Sieglinde Pfaendler...

2010-03-14T23:59:59.000Z

411

Synthesis of ZnO Microtubes by a Simple Wet Process Using Zn ...  

Science Conference Proceedings (OSTI)

Production of Apatites and Calcium Phosphate from Fish By-Products · Remediation of Semiconductor Waste Using an Iron Sorbant Prepared via a Low  ...

412

The Dielectric Properties and Phase Transitions of [Pb(Zn{sub 1/3}Nb{sub 2/3})O{sub 3}]{sub 0.905} (PbTiO{sub 3}){sub 0.095}: Influence of Pressure  

Science Conference Proceedings (OSTI)

Studies of the influences of temperature, hydrostatic pressure, dc biasing field and frequency on the dielectric constant ({epsilon}{prime}) and loss (tan {delta}) of single crystal [pb (Zn{sub 1/3}Nb{sub 2/3})O{sub 3}]{sub 0.905} (PbTiO{sub 3}){sub 0.095}, or PZN-9.5PT for short, have provided a detailed view of the ferroelectric (FE) response and phase transitions of this technologically important material. While at 1 bar, the crystal exhibits on cooling a cubic-to-tetragonal FE transition followed by a second transition to a rhombohedral phase, pressure induces a FE-to-relaxer crossover, the relaxer phase becoming the ground state at pressures {ge}5 kbar. Analogy with earlier results suggests that this crossover is a common feature of compositionally-disordered soft mode ferroelectrics and can be understood in terms of a decrease in the correlation length among polar domains with increasing pressure. Application of a dc biasing electric field at 1 bar strengthens FE correlations, and can at high pressure re-stabilize the FE response. The pressure-temperature-electric field phase diagram was established. In the absence of dc bias the tetragonal phase vanishes at high pressure, the crystal exhibiting classic relaxor behavior. The dynamics of dipolar motion and the strong deviation from Curie-Weiss behavior of the susceptibility in the high temperature cubic phase are discussed.

SAMARA,GEORGE A.; VENTURINI,EUGENE L.; SCHMIDT,V. HUGO

2000-08-01T23:59:59.000Z

413

DOE-HDBK-1141-2001; Radiological Assessor Training, Overheads...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

maintained and calibrated * Reviewed for appropriateness: - Types, levels, and energies of radiation - Environmental conditions * Routinely tested for operability OT...

414

Diffusion Couple Investigation of the Mg-Zn System  

Science Conference Proceedings (OSTI)

Relevant interdiffusion coefficients were calculated for the phases present by ... This study was sponsored by the US Department of Energy, Office of Energy ... Applications: First Year Results from the GREEN METALLURGY EU Project ... K- 38: Production of Mg-Ni Alloy by Consumable Cathode Molten Salt Electrolysis.

415

DEVELOPMENT OF HIGH STRENGTH AND DUCTILITY Mg-Nd-Zn ...  

Science Conference Proceedings (OSTI)

Jul 20, 2012 ... If the price of this product displays as $0.00 for your customer category, you may download it for free. You must, however, add it to your cart and ...

416

Novel Properties of Zn Coating Deposited by Electro-Plasma ...  

Science Conference Proceedings (OSTI)

Abstract Scope, State of the art Electro-plasma technology (EPT) was ... was characterized by Electron Microscopy, Energy Dispersive Spectroscopy, X-ray ...

417

Synthesis and Characterization of Co-ZnO Composite  

Science Conference Proceedings (OSTI)

Overview of Microstructural Models Applied to Hot Rolling Mill for Long ... Study of Composite Materials Application for Horizontal Axis Wind Turbine Blades.

418

Rechargeable Zn-MnO sub 2 alkaline batteries  

SciTech Connect

In this paper progress in the development of rechargeable alkaline zinc-manganese dioxide cells is described. The advantages and limitations of the system are evaluated. Laboratory tests run on commercial primary alkaline cells as well as model simulations of a bipolar MnO{sub 2} electrode show that the rechargeable alkaline battery may be able to compete with lead-acid, nickel-cadmium, and secondary lithium cells for low- to moderate-rate applications. However, because of this poor performance at high rates and low temperatures, the alkaline MnO{sub 2} battery is not suitable for present automotive starting applications.

Wruck, W.J.; Reichman, B.; Bullock, K.R.; Kao, W.H. (Corporate Applied Research, Johnson Controls, Inc., Milwaukee, WI (US))

1991-12-01T23:59:59.000Z

419

Study on Directional Solidification Microstructures of Mg-Zn-Gd ...  

Science Conference Proceedings (OSTI)

K2: Microstructural Development of Plutonium Alloys via Cooling Curve Analysis · K3: Preparation of High Purity Tellurium by Zone Refining Process.

420

CdZnTe Detectors Development in the NNS Department  

E-Print Network (OSTI)

. Hossain, K. Kim, G. Yang, and R. James Nonproliferation and National Security Department Brookhaven

Homes, Christopher C.

Note: This page contains sample records for the topic "zn zurn ot" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Influence of Zn Additions on Age Hardening Response and ...  

Science Conference Proceedings (OSTI)

... on Age Hardening Response and Microstructure of Mg-0.3at.%Ca Alloys. Author(s), Keiichiro Oh-ishi, Chamini L Mendis, Ryuichi Watanabe, Kazuhiro Hono.

422

069 Zinc Oxide (ZnO) and Bandgap Engineering for ...  

Science Conference Proceedings (OSTI)

005 Calcium Phosphates for Drug Carrier: Adsorption and Release Kinetics of Drugs ... 058 Properties Optimization of Refractory Mineral Resources in China.

423

025 Structural Analysis and Characterization of Zn-Substituted Nano ...  

Science Conference Proceedings (OSTI)

005 Calcium Phosphates for Drug Carrier: Adsorption and Release Kinetics of Drugs ... 058 Properties Optimization of Refractory Mineral Resources in China.

424

Reduced Graphene Sheets Decorated with ZnO Flowers by ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, 2013 TMS Annual Meeting & Exhibition. Symposium , 2013 Functional Nanomaterials: Synthesis, Properties and Applications.

425

Ultrafine ZnO Nanoparticles Synthesized by Ultraviolet ...  

Science Conference Proceedings (OSTI)

Author(s), Jyh Ming Wu, Hsin-Hsien Yeh, Hong-Ching Lin. On-Site ... Water molecular was found to be acted as key compoments during the formation process.

426

One-Dimensional ZnO Nanostructures for Photonic and ...  

Science Conference Proceedings (OSTI)

Approaching Multimaterial 3D Nanostructured Gas Phase Nanoxerographic Printers · Carbon Nanotube Coatings Laser Power and Energy Measurements.

427

Behavior analysis of Ag in Ag-Sn-Zn alloy  

Science Conference Proceedings (OSTI)

Commissioning of a Second Cobalt Recovery Furnace at Nchanga Smelter .... Study of Dielectric Properties and Drying Characteristics on Zinc Alloy Power from ...

428

Corrosion Resistance of Metals in Molten Zn Alloys - Programmaster ...  

Science Conference Proceedings (OSTI)

Oxidation Studies of HVAS-sprayed Nanostructured Coatings at Elevated Temperature · Oxide Based Thermal Sprayed Coatings for Metal Dusting Applications.

429

Bioavailability of Cd, Zn and Se in two marine fish.  

E-Print Network (OSTI)

??xxi, 210 leaves : ill. ; 30 cm HKUST Call Number: Thesis BIOL 2007 Zhang It is valuable to study the bioavailability of trace metal… (more)

Zhang, Li

2007-01-01T23:59:59.000Z

430

ZnO Nanorods as Antireflective Coatings for Single Crystalline ...  

Science Conference Proceedings (OSTI)

Graphene Coating-enabled Surface Plasmon Coupled Emission and Optical Diode ... Synthesis of Monolithic Iron Incorporated Silica Aerogels by Ambient ...

431

In-place arithmetic for polynomials over Zn ... - CECM  

E-Print Network (OSTI)

In order to do this most efficiently, one chooses the primes. Pl,...,Pn to be the biggest primes .... of magnitude at most (n - 1) 2. When R is Zp[x]/(a) where a is a  ...

432

Ultrafast Laser Induced Structures in ZnSe  

Science Conference Proceedings (OSTI)

High Thermal Energy Storage Density LiNO3-KNO3-NaNO2-KNO2 Quaternary Molten Salt System for Parabolic Trough Concentrating Solar Power Generation.

433

Microstructures and Properties Modulation for ZnO Thin Films  

Science Conference Proceedings (OSTI)

A giant magnetic moment of 6.1 uB/Co and a high Curie temperature of 790 K are observed ... I5: Giant Magnetoresistance of CoNi/Cu Multilayered Nanowires ...

434

Deformation Behavior of Mg-Al-Zn Alloy Single Crystals  

Science Conference Proceedings (OSTI)

Synthesis and Characterization of Plasma Polymerized Thin Films Deposited from Benzene and Hexamethyldisiloxane Using (PECVD) Method · Synthesis and ...

435

characterization of precipitation in mg-zn-ce-(ca) alloys  

Science Conference Proceedings (OSTI)

Jul 20, 2012 ... TMS: The Minerals, Metals and Materials Society Home ... The addition of rare earth elements to magnesium alloys has been noted to improve ...

436

Photoluminescence and polarized photodetection of single ZnO nanowires  

E-Print Network (OSTI)

and Materials Science & Department of Electrical Engineeringof Electrical Engineering and Computer Science,University of

2004-01-01T23:59:59.000Z

437

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

E-Print Network (OSTI)

pH (CaCl 2 ) GLO LUC2 BAS Limestone Dolomite Limestone TOC (Five soils (GLO, TAL, BAS, LAUS, SIS) had developed frommaterial >2 mm of SIS, LAUS and BAS, white (WP) and reddish-

Jacquat, Olivier

2009-01-01T23:59:59.000Z

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