Sample records for gallium selenium cigs

  1. Electrical Bias as an Alternate Method for Reproducible Measurement of Copper Indium Gallium Diselenide (CIGS) Photovoltaic Modules: Preprint

    SciTech Connect (OSTI)

    Deline, C.; Stokes, A.; Silverman, T. J.; Rummel, S.; Jordan, D.; Kurtz, S.

    2012-08-01T23:59:59.000Z

    Light-to-dark metastable changes in thin-film photovoltaic (PV) modules can introduce uncertainty when measuring module performance on indoor flash testing equipment. This study describes a method to stabilize module performance through forward-bias current injection rather than light exposure. Measurements of five pairs of thin-film copper indium gallium diselenide (CIGS) PV modules indicate that forward-bias exposure maintained the PV modules at a stable condition (within 1%) while the unbiased modules degraded in performance by up to 12%. It was additionally found that modules exposed to forward bias exhibited stable performance within about 3% of their long-term outdoor exposed performance. This carrier-injection method provides a way to reduce uncertainty arising from fast transients in thin-film module performance between the time a module is removed from light exposure and when it is measured indoors, effectively simulating continuous light exposure by injecting minority carriers that behave much as photocarriers do. This investigation also provides insight into the initial light-induced transients of thin-film modules upon outdoor deployment.

  2. Long-Term Performance Data and Analysis of CIS/CIGS Modules Deployed Outdoors

    SciTech Connect (OSTI)

    del Cueto, J.A.; Rummel, S.; Kroposki, B.; Anderberg, A.

    2008-11-01T23:59:59.000Z

    The long-term performance data of copper indium diselenide (CIS) and gallium-alloyed CIS (CIGS) photovoltaic (PV) modules are investigated to assess the reliability of this technology.

  3. Long-Term Performance Data and Analysis of CIS/CIGS Modules Deployed Outdoors (Presentation)

    SciTech Connect (OSTI)

    del Cueto, J. A.; Kroposki, B.; Rummel, S.; Anderberg, A.

    2008-08-10T23:59:59.000Z

    The long-term performance data of copper indium diselenide (CIS) and gallium-alloyed CIS (CIGS) photovoltaic (PV) modules are investigated to assess the reliability of this technology.

  4. NREL scientists develop robust, high-performance IZO transparent contact for CIGS solar cells.

    E-Print Network [OSTI]

    NREL scientists develop robust, high-performance IZO transparent contact for CIGS solar cells indium gallium diselenide (CIGS) solar cell is zinc oxide (ZnO). The problem is that unprotected Zn is a lifetime-limiting problem that is currently addressed solely through encapsulation. Fundamentally improving

  5. Comparative alternative materials assessment to screen toxicity hazards in the life cycle of CIGS thin film photovoltaics

    E-Print Network [OSTI]

    Eisenberg, DA; Yu, M; Lam, CW; Ogunseitan, OA; Schoenung, JM

    2013-01-01T23:59:59.000Z

    Ga)(S,Se) 2 based thin ?lm photovoltaics: present status andcycle of CIGS thin ?lm photovoltaics Daniel A. Eisenberg a ,selenium–sul?de Thin ?lm photovoltaics Life cycle thinking a

  6. Preparation of CIGS-based solar cells using a buffered electrodeposition bath

    DOE Patents [OSTI]

    Bhattacharya, Raghu Nath (Littleton, CO)

    2007-11-20T23:59:59.000Z

    A photovoltaic cell exhibiting an overall conversion efficiency of at least 9.0% is prepared from a copper-indium-gallium-diselenide thin film. The thin film is prepared by simultaneously electroplating copper, indium, gallium, and selenium onto a substrate using a buffered electro-deposition bath. The electrodeposition is followed by adding indium to adjust the final stoichiometry of the thin film.

  7. Diffusion of indium and gallium in Cu(In,Ga)Se2 thin film solar cells

    E-Print Network [OSTI]

    Rockett, Angus

    conversion efficiency of solar cells made from this material [1]. One of the special qualities of the CIGS improve the solar cell performance. In many of the different CIGS fabrication techniques, an in depthDiffusion of indium and gallium in Cu(In,Ga)Se2 thin film solar cells O. Lundberga,*, J. Lua , A

  8. Process Development for CIGS Based Thin Film Photovoltaics Modules, Phase II Technical Report

    SciTech Connect (OSTI)

    Britt, J.; Wiedeman, S.; Albright, S.

    2000-11-09T23:59:59.000Z

    As a technology partner with NREL, Global Solar Energy (GSE) has initiated an extensive and systematic plan to accelerate the commercialization of thin-film photovoltaics (PV) based on copper indium gallium diselenide (CIGS). The distinguishing feature of the GSE manufacturing process is the exclusive use of lightweight, flexible substrates. GSE has developed the technology to fabricate CIGS photovoltaics on both stainless-steel and polymer substrates. CIGS deposited on flexible substrates can be fabricated into either flexible or rigid modules. Low-cost, rigid PV panels for remote power, bulk/utility, telecommunication, and rooftop applications have been produced by affixing the flexible substrate to an inexpensive rigid panel by lamination or adhesive. Stainless-steel-based PV modules are fabricated by a novel interconnect method that avoids the use of wires or foils and soldered connections. In the case of polymer-based PV modules, the continuous roll is not sectioned into individual panels until the module buss and power leads are attached. Roll-to-roll vacuum deposition has several advantages that translate directly to reduced capital costs, greater productivity, improved yield, greater reliability, lower maintenance, and a larger volume of PV material. In combination with roll-to-roll processing, GSE has developed evaporation deposition operations that enable low-cost and high-efficiency CIGS modules. The CIGS deposition process relies heavily on effusion source technology developed at GSE, and solving numerous problems was an integral part of the source development effort. Cell interconnection for thin-film CIGS modules on a polyimide substrate presents a considerable challenge.

  9. Effects of Metastabilities on CIGS Photovoltaic Modules

    Broader source: Energy.gov [DOE]

    This poster describes a SunShot Initiative solar project led by a team from Nexcis Photovoltaic Technology entitled "Effects of Metastabilities on CIGS Photovoltaic Modules." The team studied the driving force of the mechanisms which governs the different observed phases during storage, light exposition and annealing. The aim of this study is to obtain a better understanding of this phenomenon and hence a better evaluation of its impact on solar panel reliability.

  10. Stress Induced Degradation Modes in CIGS Mini-Modules: Preprint

    SciTech Connect (OSTI)

    Kempe, M. D.; Terwilliger, K. M.; Tarrant, D.

    2008-05-01T23:59:59.000Z

    This study demonstrates that the method of encapsulation can affect the long-term stability of CIGS modules, principally through interactions with the ZnO.

  11. Preparation Of Copper Indium Gallium Diselenide Films For Solar Cells

    DOE Patents [OSTI]

    Bhattacharya, Raghu N. (Littleton, CO); Contreras, Miguel A. (Golden, CO); Keane, James (Lakewood, CO); Tennant, Andrew L. (Denver, CO), Tuttle, John R. (Denver, CO); Ramanathan, Kannan (Lakewood, CO); Noufi, Rommel (Golden, CO)

    1998-08-08T23:59:59.000Z

    High quality thin films of copper-indium-gallium-diselenide useful in the production of solar cells are prepared by electrodepositing at least one of the constituent metals onto a glass/Mo substrate, followed by physical vapor deposition of copper and selenium or indium and selenium to adjust the final stoichiometry of the thin film to approximately Cu(In,Ga)Se.sub.2. Using an AC voltage of 1-100 KHz in combination with a DC voltage for electrodeposition improves the morphology and growth rate of the deposited thin film. An electrodeposition solution comprising at least in part an organic solvent may be used in conjunction with an increased cathodic potential to increase the gallium content of the electrodeposited thin film.

  12. CIGS Material and Device Stability: A Processing Perspective (Presentation)

    SciTech Connect (OSTI)

    Ramanathan, K.

    2012-03-01T23:59:59.000Z

    This is a general overview of CIGS material and device fundamentals. In the first part, the basic features of high efficiency CIGS absorbers and devices are described. In the second part, some examples of previous collaboration with Shell Solar CIGSS graded absorbers and devices are shown to illustrate how process information was used to correct deviations and improve the performance and stability.

  13. Commercialization of High Efficiency Low Cost CIGS Technology Based on Electroplating: Final Technical Progress Report, 28 September 2007 - 30 June 2009

    SciTech Connect (OSTI)

    Basol, B.

    2010-08-01T23:59:59.000Z

    This report describes SoloPower's work as a Photovoltaic Technology Incubator awardee within the U.S. Department of Energy's Solar Energy Technologies Program. The term of this subcontract with the National Renewable Energy Laboratory was two years. The project focused on SoloPower's electrodeposition-based copper indium gallium (di)selenide (CIGS) technology. Under this subcontract, SoloPower improved the quality of its flexible metal substrates, increased the size of its solar cells from 0.5 cm2 to 120 cm2, increased the small-area cell efficiencies from near 11% to near 14%, demonstrated large-area cells, and developed a module manufacturing process.

  14. Method of junction formation for CIGS photovoltaic devices

    DOE Patents [OSTI]

    Delahoy, Alan E. (Rocky Hill, NJ)

    2010-01-26T23:59:59.000Z

    Sulfur is used to improve the performance of CIGS devices prepared by the evaporation of a single source ZIS type compound to form a buffer layer on the CIGS. The sulfur may be evaporated, or contained in the ZIS type material, or both. Vacuum evaporation apparatus of many types useful in the practice of the invention are known in the art. Other methods of delivery, such as sputtering, or application of a thiourea solution, may be substituted for evaporation.

  15. Method of junction formation for CIGS photovoltaic devices

    DOE Patents [OSTI]

    Delahoy, Alan E.

    2006-03-28T23:59:59.000Z

    Sulfur is used to improve the performance of CIGS devices prepared by the evaporation of a single source ZIS type compound to form a buffer layer on the CIGS. The sulfur may be evaporated, or contained in the ZIS type material, or both. Vacuum evaporation apparatus of many types useful in the practice of the invention are known in the art. Other methods of delivery, such as sputtering, or application of a thiourea solution, may be substituted for evaporation.

  16. Comparative alternative materials assessment to screen toxicity hazards in the life cycle of CIGS thin film photovoltaics

    E-Print Network [OSTI]

    Eisenberg, DA; Yu, M; Lam, CW; Ogunseitan, OA; Schoenung, JM

    2013-01-01T23:59:59.000Z

    aspects of ?exible CIGS solar cells and modules, Sol. Energycell technologies [2,3]. CIGS solar cells are comprised oflayers are used in CIGS solar cells, as illustrated in Table

  17. Manufacturing-Friendly Advance Seen in CIGS Solar Cell Processing (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2011-05-01T23:59:59.000Z

    Scientists developed a robust, high-performance amorphous InZnO transparent contact for CIGS solar cells.

  18. CIGS Solar Cell on Flexible Stainless Steel Substrate Fabricated by Sputtering Method: Simulation and Experimental Results

    E-Print Network [OSTI]

    Kanicki, Jerzy

    CIGS Solar Cell on Flexible Stainless Steel Substrate Fabricated by Sputtering Method: Simulation-electronic properties of the Cu(InGa)Se2(CIGS) solar cell fabricated by sputtering method on stainless steel substrate are consistent with each other. 1. Introduction Flexible Cu In Ga Se (CIGS) solar cells are very attractive

  19. Numerical Modeling of CIGS Solar Cells: Definition of the Baseline and

    E-Print Network [OSTI]

    Sites, James R.

    Thesis Numerical Modeling of CIGS Solar Cells: Definition of the Baseline and Explanation our supervision by Markus Gloeckler entitled "Numerical Modeling of CIGS Solar Cells: Definition. A three-layer structure, simulating a Cu(InGa)Se2 (CIGS) heterojunction solar cell, was set up using

  20. DISSERTATION THE EFFECT OF TRAPPING DEFECTS ON CIGS SOLAR-CELL

    E-Print Network [OSTI]

    Sites, James R.

    DISSERTATION THE EFFECT OF TRAPPING DEFECTS ON CIGS SOLAR-CELL PERFORMANCE Submitted by Pamela K ENTITLED THE EFFECT OF TRAPPING DEFECTS ON CIGS SOLAR-CELL PERFORMANCE BE ACCEPTED AS FULFILLING IN PART RE OF DISSERTATION THE EFFECT OF TRAPPING DEFECTS ON CIGS SOLAR-CELL PERFORMANCE The relationship between basic solar-cell

  1. Measuring sheet resistance of CIGS solar cell's window layer by spatially resolved electroluminescence imaging

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1/12 Measuring sheet resistance of CIGS solar cell's window layer by spatially resolved model to simulate the behavior of CIGS solar cells based on the spread sheet resistance effect on the determination of the window layer sheet resistance in CIGS solar cells, but our approach could be transferred

  2. Synthesis, characterization, and exciton dynamics of II-VI semiconducting nanomaterials and ab-initio studies for applications in explosives sensing

    E-Print Network [OSTI]

    Cooper, Jason Kyle

    2013-01-01T23:59:59.000Z

    gallium diselenide (CIGS) solar cells were studied. TheCIGS (copper indium gallium diselenide) thin film solar cells

  3. NREL Produces Highly Efficient, Wide-Bandgap, Thin-Film Solar Cells (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2012-09-01T23:59:59.000Z

    Researchers at the National Renewable Energy Laboratory (NREL) are finding new ways to manufacture thin-film solar cells made from copper, indium, gallium, and selenium - called CIGS cells - that are different than conventional CIGS solar cells. Their use of high-temperature glass, designed by SCHOTT AG, allows higher fabrication temperatures, opening the door to new CIGS solar cells employing light-absorbing materials with wide 'bandgaps.'

  4. Characterization and Analysis of CIGS and CdTE Solar Cells: December 2004 - July 2008

    SciTech Connect (OSTI)

    Sites, J. R.

    2009-01-01T23:59:59.000Z

    The work reported here embodies a device-physics approach based on careful measurement and interpretation of data from CIGS and CdTe solar cells.

  5. Comparative alternative materials assessment to screen toxicity hazards in the life cycle of CIGS thin film photovoltaics

    E-Print Network [OSTI]

    Eisenberg, DA; Yu, M; Lam, CW; Ogunseitan, OA; Schoenung, JM

    2013-01-01T23:59:59.000Z

    3 is the solar panel with the lowest-hazard CIGS solar cellde (CIGS) solar cells (found within solar panels) of greatersolar cell material compositions found within solar panels.

  6. NUMERICAL MODELING OF CIGS AND CdTe SOLAR CELLS: SETTING THE BASELINE

    E-Print Network [OSTI]

    Sites, James R.

    NUMERICAL MODELING OF CIGS AND CdTe SOLAR CELLS: SETTING THE BASELINE M. Gloeckler, A important complications that are often found in experimental CIGS and CdTe solar cells. 1. INTRODUCTION Numerical modeling of polycrystalline thin-film solar cells is an important strategy to test the viability

  7. CIG The Role of the Academic Mentor Page 1 Academic Mentoring Program

    E-Print Network [OSTI]

    Kaessmann, Henrik

    CIG ­ The Role of the Academic Mentor Page 1 Academic Mentoring Program The Role of an Academic Mentor The Center for Integrative Genomics (CIG) at the University of Lausanne (UNIL) offers an academic mentoring program to its PhD students. The academic mentoring program is one arm of a two-tier mentoring

  8. TOWARDS CIGS SOLAR CELLS WITH REDUCED FILM THICKNESS: A STUDY OF OPTICAL PROPERTIES AND OF PHOTONIC STRUCTURES FOR LIGHT TRAPPING

    E-Print Network [OSTI]

    TOWARDS CIGS SOLAR CELLS WITH REDUCED FILM THICKNESS: A STUDY OF OPTICAL PROPERTIES AND OF PHOTONIC ABSTRACT: In view of large-scale exploitation of CuIn1-xGaxSe2 (CIGS) solar cells for photovoltaic energy. In this work we perform a full study of optical properties of CIGS solar cells grown by a hybrid sputtering

  9. DISTORTIONS TO CURRENT-VOLTAGE CURVES OF CIGS CELLS WITH SPUTTERED Zn(O,S) BUFFER LAYERS

    E-Print Network [OSTI]

    Sites, James R.

    alternative to CdS for (CIGS) thin-film solar cells' buffer layer. It has a higher band gap and thus allows to current- voltage (J-V) curves of sputtered-Zn(O,S)/CIGS solar cells. A straightforward photodiode model partner in the CIGS team, and Russell for showing me the solar cells characterization, and John, Jen

  10. Explanation of Light/Dark Superposition Failure in CIGS Solar Cells Markus Gloeckler, Caroline R. Jenkins, and James R. Sites

    E-Print Network [OSTI]

    Sites, James R.

    Explanation of Light/Dark Superposition Failure in CIGS Solar Cells Markus Gloeckler, Caroline R ABSTRACT CIGS solar cells in many cases show a failure of light/dark superposition of their current feature in CuIn1-xGaxSe2 (CIGS) solar cells is the lack of superposition between light and dark current

  11. Electrospun Gallium Nitride Nanofibers

    SciTech Connect (OSTI)

    Melendez, Anamaris; Morales, Kristle; Ramos, Idalia [University of Puerto Rico at Humacao, Humacao (Puerto Rico); Campo, Eva [Centre Nacional de Microelectronica, Barcelona (Spain); Santiago, Jorge J. [University of Pennsylvania, Philadelphia (United States)

    2009-04-19T23:59:59.000Z

    The high thermal conductivity and wide bandgap of gallium nitride (GaN) are desirable characteristics in optoelectronics and sensing applications. In comparison to thin films and powders, in the nanofiber morphology the sensitivity of GaN is expected to increase as the exposed area (proportional to the length) increases. In this work we present electrospinning as a novel technique in the fabrication of GaN nanofibers. Electrospinning, invented in the 1930s, is a simple, inexpensive, and rapid technique to produce microscopically long ultrafine fibers. GaN nanofibers are produced using gallium nitrate and dimethyl-acetamide as precursors. After electrospinning, thermal decomposition under an inert atmosphere is used to pyrolyze the polymer. To complete the preparation, the nanofibers are sintered in a tube furnace under a NH{sub 3} flow. Both scanning electron microscopy and profilometry show that the process produces continuous and uniform fibers with diameters ranging from 20 to a few hundred nanometers, and lengths of up to a few centimeters. X-ray diffraction (XRD) analysis shows the development of GaN nanofibers with hexagonal wurtzite structure. Future work includes additional characterization using transmission electron microscopy and XRD to understand the role of precursors and nitridation in nanofiber synthesis, and the use of single nanofibers for the construction of optical and gas sensing devices.

  12. Gallium Safety in the Laboratory

    SciTech Connect (OSTI)

    Cadwallader, L.C.

    2003-05-07T23:59:59.000Z

    A university laboratory experiment for the US Department of Energy magnetic fusion research program required a simulant for liquid lithium. The simulant choices were narrowed to liquid gallium and galinstan (Ga-In-Sn) alloy. Safety information on liquid gallium and galinstan were compiled, and the choice was made to use galinstan. A laboratory safety walkthrough was performed in the fall of 2002 to support the galinstan experiment. The experiment has been operating successfully since early 2002.

  13. Potential effects of gallium on cladding materials

    SciTech Connect (OSTI)

    Wilson, D.F.; Beahm, E.C.; Besmann, T.M.; DeVan, J.H.; DiStefano, J.R.; Gat, U.; Greene, S.R.; Rittenhouse, P.L.; Worley, B.A.

    1997-10-01T23:59:59.000Z

    This paper identifies and examines issues concerning the incorporation of gallium in weapons derived plutonium in light water reactor (LWR) MOX fuels. Particular attention is given to the more likely effects of the gallium on the behavior of the cladding material. The chemistry of weapons grade (WG) MOX, including possible consequences of gallium within plutonium agglomerates, was assessed. Based on the calculated oxidation potentials of MOX fuel, the effect that gallium may have on reactions involving fission products and possible impact on cladding performance were postulated. Gallium transport mechanisms are discussed. With an understanding of oxidation potentials and assumptions of mechanisms for gallium transport, possible effects of gallium on corrosion of cladding were evaluated. Potential and unresolved issues and suggested research and development (R and D) required to provide missing information are presented.

  14. Cost and Reliability Improvement for CIGS-Based PV on Flexible Substrate, Phase II: 26 September 2007 - 25 September 2008

    SciTech Connect (OSTI)

    Wiedeman, S.

    2009-03-01T23:59:59.000Z

    Global Solar's CIGS manufacturing cost has decreased by increased automation, higher materials utilization, and greater capacity with higher rates in all tools.

  15. Analysis of Alternate Methods to Obtain Stabilized Power Performance of CdTe and CIGS PV Modules (Presentation)

    SciTech Connect (OSTI)

    del Cueto, J. A.; Deline, C. A.; Rummel, S.

    2011-02-01T23:59:59.000Z

    This presentation outlines an analysis of alternate methods to obtain stabilized power performance of CdTe and CIGS PV modules.

  16. Production of selenium-72 and arsenic-72

    DOE Patents [OSTI]

    Phillips, D.R.

    1993-04-20T23:59:59.000Z

    Methods are described for producing selenium-72, separating it from its daughter isotope arsenic-72, and generating multiple portions of a solution containing arsenic-72 from a reusable parent substance comprised of selenium-72.

  17. H I ASYMMETRIES IN THE ISOLATED GALAXY CIG 292

    SciTech Connect (OSTI)

    Portas, Antonio; Scott, Tom C.; Verdes-Montenegro, Lourdes; Sulentic, Jack; Sengupta, Chandreyee [Instituto de Astrofisica de Andalucia (CSIC), Glorieta de AstronomIa s/n, 18008 Granada (Spain); Brinks, Elias; Heesen, Volker [Centre for Astrophysics, University of Hertfordshire, Hatfield, Herts AL10 9AB (United Kingdom); Bosma, Albert; Athanassoula, E. [Laboratoire d'Astrophysique de Marseille (LAM), UMR6110, CNRS/Universite de Provence/CNRS, Technopole de Marseille Etoile, 38 rue Frederic Joliot Curie, 13388 Marseille CEDEX 13 (France); Espada, Daniel [National Astronomical Observatory of Japan (NAOJ), 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Verley, Simon [Departamento de Fisica Teorica y del Cosmos, Facultad de Ciencias, Universidad de Granada (Spain); Yun, Min [Department of Astronomy, University of Massachusetts, 710 North Pleasant Street, Amherst, MA 01003 (United States)

    2011-09-20T23:59:59.000Z

    We present Expanded Very Large Array (EVLA) D-array observations of the 21 cm line of neutral hydrogen (H I) of CIG 292, an isolated SA(s)b galaxy at a distance of {approx}24.3 Mpc. From previous H I single dish observations the galaxy was known to have a mildly asymmetric H I profile (A {sub flux} = 1.23 {+-} 0.3). Our EVLA observations show there is {approx}12% more H I projected south of the optical center (approaching velocities) than in the north (receding velocities), despite the H I extending {approx}16% further to the north than the south. The H I projected within the optical disk must have been perturbed within the H I relaxation time ({approx}10{sup 8} yr) which implies that this cannot have been caused by any of the three nearest companions, as their distance ({approx}0.5 Mpc) is too large. Neither H I-rich companions nor tidal tails were found within our field of view and velocity range covered. Our kinematical data suggest that the inner part harbors an oval distortion whereas the outer regions show signs of a modest warp. The mild asymmetry in the H I global profile thus actually masks stronger asymmetries in the two-dimensional distributions of gas and star-forming regions in this galaxy. Since the galaxy is isolated, this must predominantly be due to processes related to its formation and secular evolution.

  18. P-type gallium nitride

    DOE Patents [OSTI]

    Rubin, Michael (Berkeley, CA); Newman, Nathan (Montara, CA); Fu, Tracy (Berkeley, CA); Ross, Jennifer (Pleasanton, CA); Chan, James (Berkeley, CA)

    1997-01-01T23:59:59.000Z

    Several methods have been found to make p-type gallium nitride. P-type gallium nitride has long been sought for electronic devices. N-type gallium nitride is readily available. Discovery of p-type gallium nitride and the methods for making it will enable its use in ultraviolet and blue light-emitting diodes and lasers. pGaN will further enable blue photocathode elements to be made. Molecular beam epitaxy on substrates held at the proper temperatures, assisted by a nitrogen beam of the proper energy produced several types of p-type GaN with hole concentrations of about 5.times.10.sup.11 /cm.sup.3 and hole mobilities of about 500 cm.sup.2 /V-sec, measured at 250.degree. K. P-type GaN can be formed of unintentionally-doped material or can be doped with magnesium by diffusion, ion implantation, or co-evaporation. When applicable, the nitrogen can be substituted with other group III elements such as Al.

  19. P-type gallium nitride

    DOE Patents [OSTI]

    Rubin, M.; Newman, N.; Fu, T.; Ross, J.; Chan, J.

    1997-08-12T23:59:59.000Z

    Several methods have been found to make p-type gallium nitride. P-type gallium nitride has long been sought for electronic devices. N-type gallium nitride is readily available. Discovery of p-type gallium nitride and the methods for making it will enable its use in ultraviolet and blue light-emitting diodes and lasers. pGaN will further enable blue photocathode elements to be made. Molecular beam epitaxy on substrates held at the proper temperatures, assisted by a nitrogen beam of the proper energy produced several types of p-type GaN with hole concentrations of about 5{times}10{sup 11} /cm{sup 3} and hole mobilities of about 500 cm{sup 2} /V-sec, measured at 250 K. P-type GaN can be formed of unintentionally-doped material or can be doped with magnesium by diffusion, ion implantation, or co-evaporation. When applicable, the nitrogen can be substituted with other group III elements such as Al. 9 figs.

  20. Investigation of Some Transparent Metal Oxides as Damp Heat Protective Coating for CIGS Solar Cells: Preprint

    SciTech Connect (OSTI)

    Pern, F. J.; Yan, F.; Zaaunbrecher, B.; To, B.; Perkins, J.; Noufi, R.

    2012-10-01T23:59:59.000Z

    We investigated the protective effectiveness of some transparent metal oxides (TMO) on CIGS solar cell coupons against damp heat (DH) exposure at 85oC and 85% relative humidity (RH). Sputter-deposited bilayer ZnO (BZO) with up to 0.5-um Al-doped ZnO (AZO) layer and 0.2-um bilayer InZnO were used as 'inherent' part of device structure on CdS/CIGS/Mo/SLG. Sputter-deposited 0.2-um ZnSnO and atomic layer deposited (ALD) 0.1-um Al2O3 were used as overcoat on typical BZO/CdS/CIGS/Mo/SLG solar cells. The results were all negative -- all TMO-coated CIGS cells exhibited substantial degradation in DH. Combining the optical photographs, PL and EL imaging, SEM surface micro-morphology, coupled with XRD, I-V and QE measurements, the causes of the device degradations are attributed to hydrolytic corrosion, flaking, micro-cracking, and delamination induced by the DH moisture. Mechanical stress and decrease in crystallinity (grain size effect) could be additional degrading factors for thicker AZO grown on CdS/CIGS.

  1. Local environment and composition of magnesium gallium layered...

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

    environment and composition of magnesium gallium layered double hydroxides determined from solid-state 1H and 71Ga NMR Local environment and composition of magnesium gallium...

  2. Preparation of copper-indium-gallium-diselenide precursor films by electrodeposition for fabricating high efficiency solar cells

    DOE Patents [OSTI]

    Bhattacharya, Raghu N. (Littleton, CO); Hasoon, Falah S. (Arvada, CO); Wiesner, Holm (Golden, CO); Keane, James (Lakewood, CO); Noufi, Rommel (Golden, CO); Ramanathan, Kannan (Golden, CO)

    1999-02-16T23:59:59.000Z

    A photovoltaic cell exhibiting an overall conversion efficiency of 13.6% is prepared from a copper-indium-gallium-diselenide precursor thin film. The film is fabricated by first simultaneously electrodepositing copper, indium, gallium, and selenium onto a glass/molybdenum substrate (12/14). The electrodeposition voltage is a high frequency AC voltage superimposed upon a DC voltage to improve the morphology and growth rate of the film. The electrodeposition is followed by physical vapor deposition to adjust the final stoichiometry of the thin film to approximately Cu(In.sub.1-n Ga.sub.x)Se.sub.2, with the ratio of Ga/(In+Ga) being approximately 0.39.

  3. Chemical factors influencing selenium atomization

    E-Print Network [OSTI]

    Buren, Mary Sue

    1980-01-01T23:59:59.000Z

    Atomization. (August 1980) Mary Sue Buren, B, S. , Angelo State University Chairman of Advisory Comm1ttee: Dr. Thomas M. Vickrey Selenium in an acid1c matrix was analyzed using graphite furnace atom1c absorption with Zeeman-effect background correct1on.... Nickel(II} and lanthanum( III) were introduced as matrix modifiers to determine their effect on interferences 1n selenium atom1zation. In add1tion to matr1x mod1ficat1on, surface coating the graphite furnace with z1rconium and tantalum salts was also...

  4. Selenium speciation in ground water

    SciTech Connect (OSTI)

    Atalay, A.

    1990-07-10T23:59:59.000Z

    Selenium toxicity diseases in animals may occur when the intake exceeds 4 mg/kg and selenium deficiency symptoms may occur when dietary intake is less than 0.04 mg/kg. Since the selenium dietary requirement is very close to toxic concentration, it is important to understand the distribution of selenium in the environment. Selenium occurs in four oxidation states (-II, 0, +IV, and +VI) as selenide, elemental selenium, selenite and selenate. Selenate is reported as more soluble and less adsorbed than selenite. Selenate is more easily leached from soils and is the most available form for plants. Increased mobility of Se into the environment via anthropogenic activities, and the potential oxidation-reduction behavior of the element have made it imperative to study the aquatic chemistry of Se. For this purpose, Se species are divided into two different categories: dissolved Se (in material that passes through filters with 0.45 u openings) and particulate Se (in material of particle size > 0.45 mm) typically suspended sediment and other suspended solids. Element and colloidal phase, not truly dissolved, but passing through the filter is deemed to consist of selenium (-2,0). In dissolved state selenium may exist in three of its four oxidation states; Se(-II), Se(+IV), and Se(+VI). Particulate Se may exist in the same oxidation states as dissolved Se and can be found in different phases of the particulate matter. In sediments, Se may be within the organic material, iron and manganese oxides, carbonates or other mineral phases. The actual chemical forms of Se may be adsorbed to or coprecipitated with these phases (primarily selenite, SeO{sub 3}{sup 2{minus}}) and selenate, SeO{sub 4}{sup 2{minus}}. Selenide, Se(-II), can be covalently bound in the organic portion of a sediment. In addition, Se may be found in anoxic sediments as insoluble metal selenide precipitates, an insoluble elemental Se or as ferroselite (FeSe{sub 2}) and Se containing pyrite.

  5. Chemical factors influencing selenium atomization 

    E-Print Network [OSTI]

    Buren, Mary Sue

    1980-01-01T23:59:59.000Z

    Atomization. (August 1980) Mary Sue Buren, B, S. , Angelo State University Chairman of Advisory Comm1ttee: Dr. Thomas M. Vickrey Selenium in an acid1c matrix was analyzed using graphite furnace atom1c absorption with Zeeman-effect background correct1on.... Nickel(II} and lanthanum( III) were introduced as matrix modifiers to determine their effect on interferences 1n selenium atom1zation. In add1tion to matr1x mod1ficat1on, surface coating the graphite furnace with z1rconium and tantalum salts was also...

  6. In-depth analysis of CIGS film for solar cells, structural and optical characterization

    E-Print Network [OSTI]

    Slobodskyy, A; ~Ulyanenkova, T; ~Doyle, S; Powalla, M; ~Baumbach, T; ~Lemmer, U

    2010-01-01T23:59:59.000Z

    Space-resolved X-ray diffraction measurements performed on gradient-etched CuIn$_{1-x}$Ga$_x$Se$_2$ (CIGS) solar cells provide information about stress and texture depth profiles in the absorber layer. An important parameter for CIGS layer growth dynamics, the absorber thickness-dependent stress in the molybdenum back contact is analyzed. Texturing of grains and quality of the polycrystalline absorber layer are correlated with the intentional composition gradients (band gap grading). Band gap gradient is determined by space-resolved photoluminescence measurements and correlated with composition and strain profiles.

  7. CX-002541: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    Emerging Renewables Industries: Copper, Indium, Gallium, Selenium (CIGS) Linear Source Thermal DepositionCX(s) Applied: B2.2, B5.1Date: 05/19/2010Location(s): St. Paul, MinnesotaOffice(s): Energy Efficiency and Renewable Energy, Golden Field Office

  8. Kinetic determination of selenium in biological material

    SciTech Connect (OSTI)

    Efremenko, O.A.; Krasnyuk, I.I.; Kudrin, A.N.; Rudenko, B.A.

    1986-05-10T23:59:59.000Z

    A very promising method for selenium determination is a kinetic analytical procedure that combines the simplicity and availability of physical instrumentation with a low analyte detection limit. This paper reports a modification of the method to enable the determination of selenium in rat blood and involves decomposing the sample with a mixture of nitric and perchloric acids, separation of the selenium (IV) from other decomposition products, and quantitatively determining selenium by the described kinetic method using the indicator reaction of iron (II) edetate oxidation by sodium nitrate.

  9. Aquatic chemistry of selenium: evidence of biomethylation

    SciTech Connect (OSTI)

    Cooke, T.D.; Bruland, K.W.

    1987-12-01T23:59:59.000Z

    The chemical species of dissolved selenium were examined in surface waters from three sites in the San Joaquin and Imperial Valleys of California. Six dissolved selenium species were identified: the inorganic species selenate and selenite; nonvolatile organic selenides, including seleno amino acids and a dimethylselenonium ion; and the volatile methylated forms dimethyl selenide and dimethyl diselenide. The occurrences of methylated selenium species in the aquatic environment has important implications regarding the biogeochemical behavior of selenium in natural aqueous systems. Laboratory studies indicate that the nonvolatile dimethylselenonium ion can be transformed into volatile dimethyl selenide at neutral pH, providing a pathway for the in situ production of dimethyl selenide in natural waters. Geochemical flux calculations indicate that outgassing of dimethyl selenide may be an important removal mechanism for dissolved selenium from aqueous systems. 22 references, 7 figures, 1 table.

  10. Recovery of gallium from aluminum industry residues

    SciTech Connect (OSTI)

    Carvalho, M.S.; Neto, K.C.M.; Nobrega, A.W.; Medeiros, J.A.

    2000-01-01T23:59:59.000Z

    A procedure is proposed to recover gallium from flue dust aluminum residues produced in plants by using solid-phase extraction with a commercial polyether-type polyurethane foam (PUF). Gallium can be separated from high concentrations of aluminum, iron, nickel, titanium, vanadium, copper, zinc, sulfate, fluoride, and chloride by extraction with PUF from 3 M sulfuric acid and 3 M sodium chloride concentration medium with at least a 92% efficiency. Gallium backextraction was fast and quantitative with ethanol solution. In all recovery steps commercial-grade reagents could be used, including tap water. The recovered gallium was precipitated with sodium hydroxide solution, purified by dissolution and precipitation, calcinated, and the final oxide was 98.6% pure.

  11. Developing Market Opportunities for Flexible Rooftop Applications of PV Using Flexible CIGS Technology: Market Considerations

    SciTech Connect (OSTI)

    Sabnani, L.; Skumanich, A.; Ryabova, E.; Noufi, R.

    2011-01-01T23:59:59.000Z

    There has been a recent upsurge in developments for building-integrated phototovoltaics (BiPV) roof top materials based on CIGS. Several new companies have increased their presence and are looking to bring products to market for this application in 2011. For roof-top application, there are significant key requirements beyond just having good conversion efficiency. Other attributes include lightweight, as well as moisture-proof, and fully functionally reliable. The companies bringing these new BIPV/BAPV products need to ensure functionality with a rigorous series of tests, and have an extensive set of 'torture' tests to validate the capability. There is a convergence of form, aesthetics, and physics to ensure that the CIGS BiPV deliver on their promises. This article will cover the developments in this segment of the BiPV market and delve into the specific tests and measurements needed to characterize the products. The potential market sizes are evaluated and the technical considerations developed.

  12. Predicted roles of defects on band offsets and energetics at CIGS (Cu(In,Ga)Se2/CdS) solar cell interfaces and implications for improving performance

    E-Print Network [OSTI]

    Goddard III, William A.

    Predicted roles of defects on band offsets and energetics at CIGS (Cu(In,Ga)Se2/CdS) solar cell (2014) Predicted roles of defects on band offsets and energetics at CIGS (Cu(In,Ga)Se2/CdS) solar cell of CIGS (Cu(In,Ga)Se2) based solar cells (20.8% efficiency) makes them promising candidate photovoltaic

  13. (Data in kilograms of gallium content unless otherwise noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 2009. One company in Utah

    E-Print Network [OSTI]

    58 GALLIUM (Data in kilograms of gallium content unless otherwise noted) Domestic Production 98% of domestic gallium consumption. About 67% of the gallium consumed was used in integrated and Use: No domestic primary gallium recovery was reported in 2009. One company in Utah recovered

  14. Au-free Ohmic Contacts to Gallium Nitride and Graphene 

    E-Print Network [OSTI]

    Ravikirthi, Pradhyumna

    2014-08-10T23:59:59.000Z

    This work deals with Au-free contact metallization schemes for gallium nitride (GaN) and graphene semiconductors. Graphene and gallium nitride are promising materials that can potentially be integrated together in the near future for high frequency...

  15. Au-free Ohmic Contacts to Gallium Nitride and Graphene

    E-Print Network [OSTI]

    Ravikirthi, Pradhyumna

    2014-08-10T23:59:59.000Z

    This work deals with Au-free contact metallization schemes for gallium nitride (GaN) and graphene semiconductors. Graphene and gallium nitride are promising materials that can potentially be integrated together in the near future for high frequency...

  16. Effect of Gallium Nitride Template Layer Strain on the Growth...

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

    Gallium Nitride Template Layer Strain on the Growth of InxGa1-xNGaN Multiple Quantum Well Light Emitting Diodes. Effect of Gallium Nitride Template Layer Strain on the Growth of...

  17. Production of selenium-72 and arsenic-72

    DOE Patents [OSTI]

    Phillips, D.R.

    1994-12-06T23:59:59.000Z

    Methods and apparatus are described for producing selenium-72, separating it from its daughter isotope arsenic-72, and generating multiple portions of a solution containing arsenic-72 from a reusable parent substance comprised of selenium-72. The invention provides apparatus which can be located at a site where arsenic-72 is used, for purposes such as PET imaging, to produce arsenic-72 as needed, since the half-life of arsenic-72 is very short. 2 figures.

  18. Production of selenium-72 and arsenic-72

    DOE Patents [OSTI]

    Phillips, Dennis R. (Los Alamos, NM)

    1994-01-01T23:59:59.000Z

    Methods and apparatus for producing selenium-72, separating it from its daughter isotope arsenic-72, and generating multiple portions of a solution containing arsenic-72 from a reusable parent substance comprised of selenium-72. The invention provides apparatus which can be located at a site where arsenic-72 is used, for purposes such as PET imaging, to produce arsenic-72 as needed, since the half-life of arsenic-72 is very short.

  19. Production of selenium-72 and arsenic-72

    DOE Patents [OSTI]

    Phillips, Dennis R. (Los Alamos, NM)

    1995-01-01T23:59:59.000Z

    Methods and apparatus for producing selenium-72, separating it from its daughter isotope arsenic-72, and generating multiple portions of a solution containing arsenic-72 from a reusable parent substance comprised of selenium-72. The invention provides apparatus which can be located at a site where arsenic-72 is used, for purposes such as PET imaging, to produce arsenic-72 as needed, since the half-life of arsenic-72 is very short.

  20. Thin film solar cells by selenization sulfurization using diethyl selenium as a selenium precursor

    DOE Patents [OSTI]

    Dhere, Neelkanth G.; Kadam, Ankur A.

    2009-12-15T23:59:59.000Z

    A method of forming a CIGSS absorber layer includes the steps of providing a metal precursor, and selenizing the metal precursor using diethyl selenium to form a selenized metal precursor layer (CIGSS absorber layer). A high efficiency solar cell includes a CIGSS absorber layer formed by a process including selenizing a metal precursor using diethyl selenium to form the CIGSS absorber layer.

  1. Synthesis and characterization of visible emission from rare-earth doped aluminum nitride, gallium nitride and gallium aluminum nitride powders and thin films

    E-Print Network [OSTI]

    Tao, Jonathan Huai-Tse

    2010-01-01T23:59:59.000Z

    Gallium Nitride Doped With Europium," J. Appl. Phys. , 95Electroluminescence of Europium-doped Gallium Oxide ThinLuminescence Properties of Europium– terbium Double

  2. Thin Film CIGS and CdTe Photovoltaic Technologies: Commercialization, Critical Issues, and Applications; Preprint

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron Spin Transition in theTheoreticalEnergy InnovationThin Film CIGS and

  3. ZnMgO by APCVD Enabling High-Performance Mid-bandgap CIGS on Polyimide Modules: October 2009--October 2010

    SciTech Connect (OSTI)

    Woods, L.

    2011-04-01T23:59:59.000Z

    This Pre-Incubator project was designed to increase the 'real world' CIGS based photovoltaic module performance and decrease the Levelized Cost of Energy (LCOE) of systems utilizing those modules compared to our traditional CIGS based photovoltaic modules. This was enabled by a) increasing the CIGS bandgap and b) developing better matched device finishing layers to the mid-bandgap CIGS based photovoltaics; including window and buffer layers (and eventually the TCO). Incremental progress in the novel device performance was demonstrated throughout the program, and ultimately achieved performance results that exceeded the milestones ahead of schedule. Metal-oxide buffer layer devices with mid-bandgap CIGS alloys on polyimide substrates were produced with efficiencies of over 12%. Corresponding mid-bandgap devices with CdS buffers produced over 13% efficient devices. Furthermore, no obvious degradation in the device performance has been observed to date, after proper storage ambient of the different types of unencapsulated devices were identified.

  4. Gallium nitride junction field-effect transistor

    DOE Patents [OSTI]

    Zolper, John C. (Albuquerque, NM); Shul, Randy J. (Albuquerque, NM)

    1999-01-01T23:59:59.000Z

    An all-ion implanted gallium-nitride (GaN) junction field-effect transistor (JFET) and method of making the same. Also disclosed are various ion implants, both n- and p-type, together with or without phosphorous co-implantation, in selected III-V semiconductor materials.

  5. Pulmonary gallium-67 uptake in amiodarone pneumonitis

    SciTech Connect (OSTI)

    van Rooij, W.J.; van der Meer, S.C.; van Royen, E.A.; van Zandwijk, N.; Darmanata, J.I.

    1984-02-01T23:59:59.000Z

    Three patients are presented suffering from interstitial pneumonitis caused by amiodarone. Pulmonary Ga-67 uptake occurred in all three. There appeared to be a discrepancy between the scintigraphic and radiographic findings in two patients. Gallium-67 lung scintigraphy may offer an early, sensitive indicator for amiodarone pneumonitis.

  6. Gallium nitride junction field-effect transistor

    DOE Patents [OSTI]

    Zolper, J.C.; Shul, R.J.

    1999-02-02T23:59:59.000Z

    An ion implanted gallium-nitride (GaN) junction field-effect transistor (JFET) and method of making the same are disclosed. Also disclosed are various ion implants, both n- and p-type, together with or without phosphorus co-implantation, in selected III-V semiconductor materials. 19 figs.

  7. Swiss Federal Laboratories for Materials Science and Technology Advances in Thin Film PV: CIGS & CdTe

    E-Print Network [OSTI]

    Canet, Léonie

    and Photovoltaics Thin film solar cells based on compound semiconductor absorbers: CIGS and CdTe High efficiency and Photovoltaics Swiss Federal Laboratories for Material Science and Technology Key issues in high efficiency CIGSTe Laboratory for Thin Films and Photovoltaics Empa- Swiss Federal Laboratories for Material Science

  8. (Data in kilograms of gallium content unless otherwise noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 2005. One company in Utah

    E-Print Network [OSTI]

    66 GALLIUM (Data in kilograms of gallium content unless otherwise noted) Domestic Production, [(703) 648-7719, dkramer@usgs.gov, fax: (703) 648-7975] #12;67 GALLIUM Consolidation of companies and Use: No domestic primary gallium recovery was reported in 2005. One company in Utah recovered

  9. (Data in kilograms of gallium content, unless otherwise noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 1998. Two companies in

    E-Print Network [OSTI]

    66 GALLIUM (Data in kilograms of gallium content, unless otherwise noted) Domestic Production A. Kramer [(703) 648-7719, dkramer@usgs.gov, fax: (703) 648-7722] #12;67 GALLIUM Events, Trends and Use: No domestic primary gallium recovery was reported in 1998. Two companies in Oklahoma and Utah

  10. CIGS P1, P2, P3 Scribing Processes using a Pulse Programmable Industrial Fiber Laser: Preprint

    SciTech Connect (OSTI)

    Rekow, M.; Murison, R.; Panarello, T.; Dunsky, C.; Dinkel, C.; Nikumb, S.; Pern, F. J.; Mansfield, L.

    2010-10-01T23:59:59.000Z

    We describe a novel set of laser processes for the CIGS P1, P2 and P3 scribing steps, the development of which has been enabled by a unique pulse-programmable fiber laser. We find that the unique pulse control properties of this 1064 nm wavelength laser have significant effects on the material removal dynamics of the various film layers in the CIGS material system. In the case of the P2 and P3 processes, the shaped pulses create new laser/material interaction effects that permit the material to be cleanly and precisely removed with zero Heat Affected Zone (HAZ) at the edges of the scribe. The new P2 and P3 processes we describe demonstrate the first use of infrared nanosecond laser pulses that eliminate the HAZ and the consequent localized compositional changes in the CIGS absorber material that result in poor shunt resistance. SEM micrographs and EDX compositional scans are presented. For the P1 scribe, we process the bi-layer molybdenum from the film side as well as through the glass substrate. Microscopic inspection and compositional analysis of the scribe lines are not sufficient to determine electrical and optical performance in working PV modules. Therefore, to demonstrate the applicability of the infrared pulse-programmable laser to all three scribing processes for thin-film CIGS, we fabricate small-size multiple-cell monolithically interconnected mini-modules in partnership with the National Renewable Energy Laboratory (Golden, Colorado). A total of four mini-modules are produced, two utilizing all laser scribing, and two with the P2 and P3 steps mechanically scribed (by a third party) for reference. Mini-module performance data measured at NREL is presented, and we also discuss the commercialization potential of the new single-laser CIGS scribing process. Finally we present a phenomenological model to describe this physics underlying this novel ablation process.

  11. Selenium speciation in ground water. Quarterly report

    SciTech Connect (OSTI)

    Atalay, A.

    1990-07-10T23:59:59.000Z

    Selenium toxicity diseases in animals may occur when the intake exceeds 4 mg/kg and selenium deficiency symptoms may occur when dietary intake is less than 0.04 mg/kg. Since the selenium dietary requirement is very close to toxic concentration, it is important to understand the distribution of selenium in the environment. Selenium occurs in four oxidation states (-II, 0, +IV, and +VI) as selenide, elemental selenium, selenite and selenate. Selenate is reported as more soluble and less adsorbed than selenite. Selenate is more easily leached from soils and is the most available form for plants. Increased mobility of Se into the environment via anthropogenic activities, and the potential oxidation-reduction behavior of the element have made it imperative to study the aquatic chemistry of Se. For this purpose, Se species are divided into two different categories: dissolved Se (in material that passes through filters with 0.45 u openings) and particulate Se (in material of particle size > 0.45 mm) typically suspended sediment and other suspended solids. Element and colloidal phase, not truly dissolved, but passing through the filter is deemed to consist of selenium (-2,0). In dissolved state selenium may exist in three of its four oxidation states; Se(-II), Se(+IV), and Se(+VI). Particulate Se may exist in the same oxidation states as dissolved Se and can be found in different phases of the particulate matter. In sediments, Se may be within the organic material, iron and manganese oxides, carbonates or other mineral phases. The actual chemical forms of Se may be adsorbed to or coprecipitated with these phases (primarily selenite, SeO{sub 3}{sup 2{minus}}) and selenate, SeO{sub 4}{sup 2{minus}}. Selenide, Se(-II), can be covalently bound in the organic portion of a sediment. In addition, Se may be found in anoxic sediments as insoluble metal selenide precipitates, an insoluble elemental Se or as ferroselite (FeSe{sub 2}) and Se containing pyrite.

  12. Interactions of zircaloy cladding with gallium -- 1997 status

    SciTech Connect (OSTI)

    Wilson, D.F.; DiStefano, J.R.; King, J.F.; Manneschmidt, E.T.; Strizak, J.P.

    1997-11-01T23:59:59.000Z

    A four phase program has been implemented to evaluate the effect of gallium in mixed oxide (MOX) fuel derived from weapons grade (WG) plutonium on Zircaloy cladding performance. The objective is to demonstrate that low levels of gallium will not compromise the performance of the MOX fuel system in LWR. This graded, four phase experimental program will evaluate the performance of prototypic Zircaloy cladding materials against: (1) liquid gallium (Phase 1), (2) various concentrations of Ga{sub 2}O{sub 3} (Phase 2), (3) centrally heated surrogate fuel pellets with expected levels of gallium (Phase 3), and (4) centrally heated prototypic MOX fuel pellets (Phase 4). This status report describes the results of an initial series of tests for phases 1 and 2. Three types of tests are being performed: (1) corrosion, (2) liquid metal embrittlement (LME), and (3) corrosion mechanical. These tests are designed to determine the corrosion mechanisms, thresholds for temperature and concentration of gallium that may delineate behavioral regimes, and changes in mechanical properties of Zircaloy. Initial results have generally been favorable for the use of WG-MOX fuel. The MOX fuel cladding, Zircaloy, does react with gallium to form intermetallic compounds at {ge} 300 C; however, this reaction is limited by the mass of gallium and is therefore not expected to be significant with a low level (in parts per million) of gallium in the MOX fuel. While continued migration of gallium into the initially formed intermetallic compound results in large stresses that can lead to distortion, this is also highly unlikely because of the low mass of gallium or gallium oxide present and expected clad temperatures below 400 C. Furthermore, no evidence for grain boundary penetration by gallium has been observed.

  13. Light-Emitting Diodes on Semipolar Bulk Gallium Nitride Substrate...

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

    semipolar light-emitting diodes (LEDs) on low-defect bulk gallium nitride (GaN) substrates. Peak internal quantum efficiency (IQE) values of greater than 80% are...

  14. Photonuclear Reaction Cross Sections for Gallium Isotopes

    E-Print Network [OSTI]

    Serkan Akkoyun; Tuncay Bayram

    2014-09-08T23:59:59.000Z

    The photon induced reactions which are named as photonuclear reactions have a great importance in many field of nuclear, radiation physics and related fields. Since we have planned to perform photonuclear reaction on gallium target with bremmstrahlung photons from clinical linear accelerator in the future, the cross-sections of neutron (photo-neutron ({\\gamma},xn)) and proton (photo-proton ({\\gamma},xn)) productions after photon activation have been calculated by using TALYS 1.2 computer code in this study. The target nucleus has been considered gallium which has two stable isotopes, 69Ga and 71Ga. According to the results, we have seen that the calculations are in harmony in the limited literature values. Furthermore, the pre-equilibrium and compound process contributions to the total cross-section have been investigated.

  15. Gallium nanoparticles grow where light is

    E-Print Network [OSTI]

    K. F. MacDonald; W. S. Brocklesby; V. I. Emelyanov; V. A. Fedotov; S. Pochon; K. J. Ross; G. Stevens; N. I. Zheludev

    2001-05-15T23:59:59.000Z

    The study of metallic nanoparticles has a long tradition in linear and nonlinear optics [1], with current emphasis on the ultrafast dynamics, size, shape and collective effects in their optical response [2-6]. Nanoparticles also represent the ultimate confined geometry:high surface-to-volume ratios lead to local field enhancements and a range of dramatic modifications of the material's properties and phase diagram [7-9]. Confined gallium has become a subject of special interest as the light-induced structural phase transition recently observed in gallium films [10, 11] has allowed for the demonstration of all-optical switching devices that operate at low laser power [12]. Spontaneous self-assembly has been the main approach to the preparation of nanoparticles (for a review see 13). Here we report that light can dramatically influence the nanoparticle self-assembly process: illumination of a substrate exposed to a beam of gallium atoms results in the formation of nanoparticles with a relatively narrow size distribution. Very low light intensities, below the threshold for thermally-induced evaporation, exert considerable control over nanoparticle formation through non-thermal atomic desorption induced by electronic excitation.

  16. Selenium in Oklahoma ground water and soil

    SciTech Connect (OSTI)

    Atalay, A.; Vir Maggon, D.

    1991-03-30T23:59:59.000Z

    Selenium with a consumption of 2 liters per day (5). The objectives of this study are: (1) to determine the concentrations of Se in Oklahoma ground water and soil samples. (2) to map the geographical distribution of Se species in Oklahoma. (3) to relate groundwater depth, pH and geology with concentration of Se.

  17. GALLIUM--2001 29.1 By Deborah A. Kramer

    E-Print Network [OSTI]

    the largest application for gallium, with optoelectronic devices [mostly laser diodes and light near the town of McDermitt in Humboldt County, NV. The company began initial drilling in October and announced preliminary results in November. According to the drilling results, gallium concentrations over

  18. Selenium Poisoning of Wildlife and Western Agriculture: Cause and Effect

    SciTech Connect (OSTI)

    Korte, N.E.

    2000-02-01T23:59:59.000Z

    This project examined the hypothesis that selenium contamination is not the principal cause of the decline of endemic fish species in the Upper Colorado Basin. Activities employed to test this hypothesis included a reconnaissance of locations altered by recent road construction, a re-interpretation of available literature regarding selenium toxicity, and the interpretation of unpublished data obtained from the Upper Colorado Basin Fish Recovery Program. The project demonstrates that most of the evidence implicating selenium is circumstantial.

  19. Delta-phase manganese gallium on gallium nitride: a magnetically tunable spintronic system

    E-Print Network [OSTI]

    with Mn:Ga ratio between 1:1 to 1.5:1 is grown on wurtzite gallium nitride and scandium nitride substrates. Results suggest that for growth on wurtzite GaN, Ga-polar surface promotes quicker interface formation epitaxially on top of wide band-gap Ga-polar wurtzite GaN(0001), with controllable magnetism by adjusting

  20. Stability of CIGS Solar Cells and Component Materials Evaluated by a Step-Stress Accelerated Degradation Test Method: Preprint

    SciTech Connect (OSTI)

    Pern, F. J.; Noufi, R.

    2012-10-01T23:59:59.000Z

    A step-stress accelerated degradation testing (SSADT) method was employed for the first time to evaluate the stability of CuInGaSe2 (CIGS) solar cells and device component materials in four Al-framed test structures encapsulated with an edge sealant and three kinds of backsheet or moisture barrier film for moisture ingress control. The SSADT exposure used a 15oC and then a 15% relative humidity (RH) increment step, beginning from 40oC/40%RH (T/RH = 40/40) to 85oC/70%RH (85/70) as of the moment. The voluminous data acquired and processed as of total DH = 3956 h with 85/70 = 704 h produced the following results. The best CIGS solar cells in sample Set-1 with a moisture-permeable TPT backsheet showed essentially identical I-V degradation trend regardless of the Al-doped ZnO (AZO) layer thickness ranging from standard 0.12 ?m to 0.50 ?m on the cells. No clear 'stepwise' feature in the I-V parameter degradation curves corresponding to the SSADT T/RH/time profile was observed. Irregularity in I-V performance degradation pattern was observed with some cells showing early degradation at low T/RH < 55/55 and some showing large Voc, FF, and efficiency degradation due to increased series Rs (ohm-cm2) at T/RH ? 70/70. Results of (electrochemical) impedance spectroscopy (ECIS) analysis indicate degradation of the CIGS solar cells corresponded to increased series resistance Rs (ohm) and degraded parallel (minority carrier diffusion/recombination) resistance Rp, capacitance C, overall time constant Rp*C, and 'capacitor quality' factor (CPE-P), which were related to the cells? p-n junction properties. Heating at 85/70 appeared to benefit the CIGS solar cells as indicated by the largely recovered CPE-P factor. Device component materials, Mo on soda lime glass (Mo/SLG), bilayer ZnO (BZO), AlNi grid contact, and CdS/CIGS/Mo/SLG in test structures with TPT showed notable to significant degradation at T/RH ? 70/70. At T/RH = 85/70, substantial blistering of BZO layers on CIGS cell pieces was observed that was not seen on BZO/glass, and a CdS/CIGS sample displayed a small darkening and then flaking feature. Additionally, standard AlNi grid contact was less stable than thin Ni grid contact at T/RH ? 70/70. The edge sealant and moisture-blocking films were effective to block moisture ingress, as evidenced by the good stability of most CIGS solar cells and device components at T/RH = 85/70 for 704 h, and by preservation of the initial blue color on the RH indicator strips. The SSADT experiment is ongoing to be completed at T/RH = 85/85.

  1. amorphous selenium detectors: Topics by E-print Network

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

    The atomic processes leading to calcite growth are still debated. The presence Montes-Hernandez, German 65 Selenium and Lung Cancer: A Quantitative Analysis of Heterogeneity in the...

  2. Compatibility of ITER candidate structural materials with static gallium

    SciTech Connect (OSTI)

    Luebbers, P.R.; Michaud, W.F.; Chopra, O.K.

    1993-12-01T23:59:59.000Z

    Tests were conducted on the compatibility of gallium with candidate structural materials for the International Thermonuclear Experimental Reactor, e.g., Type 316 SS, Inconel 625, and Nb-5 Mo-1 Zr alloy, as well as Armco iron, Nickel 270, and pure chromium. Type 316 stainless steel is least resistant to corrosion in static gallium and Nb-5 Mo-1 Zr alloy is most resistant. At 400{degrees}C, corrosion rates are {approx}4.0, 0.5, and 0.03 mm/yr for type 316 SS, Inconel 625, and Nb-5 Mo- 1 Zr alloy, respectively. The pure metals react rapidly with gallium. In contrast to findings in earlier studies, pure iron shows greater corrosion than nickel. The corrosion rates at 400{degrees}C are {ge}88 and 18 mm/yr, respectively, for Armco iron and Nickel 270. The results indicate that at temperatures up to 400{degrees}C, corrosion occurs primarily by dissolution and is accompanied by formation of metal/gallium intermetallic compounds. The solubility data for pure metals and oxygen in gallium are reviewed. The physical, chemical, and radioactive properties of gallium are also presented. The supply and availability of gallium, as well as price predictions through the year 2020, are summarized.

  3. (Data in kilograms of gallium content, unless otherwise noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 1996. Two companies in

    E-Print Network [OSTI]

    on world production of primary gallium were unavailable because data on the output of the few producers62 GALLIUM (Data in kilograms of gallium content, unless otherwise noted) Domestic Production in optoelectronic devices, which include light-emitting diodes (LED's), laser diodes, photodetectors, and solar

  4. Ionic liquid-induced synthesis of selenium nanoparticles

    SciTech Connect (OSTI)

    Langi, Bhushan [Changu Kana Thakur Research Centre, New Panvel 410 206 (India)] [Changu Kana Thakur Research Centre, New Panvel 410 206 (India); Shah, Chetan; Singh, Krishankant [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)] [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Chaskar, Atul, E-mail: achaskar@rediffmail.com [Changu Kana Thakur Research Centre, New Panvel 410 206 (India)] [Changu Kana Thakur Research Centre, New Panvel 410 206 (India); Kumar, Manmohan; Bajaj, Parma N. [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)] [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

    2010-06-15T23:59:59.000Z

    A simple wet chemical method has been used to synthesize selenium nanoparticles by the reaction of ionic liquid with sodium selenosulphate, a selenium precursor, in the presence of polyvinyl alcohol stabilizer, in aqueous medium. The method is capable of producing spherical selenium nanoparticles in the size range of 76-150 nm under ambient conditions. This is a first report on the production of nano-selenium assisted by an ionic liquid. The synthesized nanoparticles can be separated easily from the aqueous sol by a high-speed centrifuge machine, and can be re-dispersed in an aqueous medium. The synthesized selenium nanoparticles have been characterized by X-ray diffraction, energy dispersive X-ray analysis, differential scanning calorimetry and transmission electron microscopy techniques.

  5. Reversible expansion of gallium-stabilized (delta)-plutonium

    SciTech Connect (OSTI)

    Wolfer, W G; Oudot, B; Baclet, N

    2006-02-27T23:59:59.000Z

    It is shown that the transient expansion of plutonium-gallium alloys observed both in the lattice parameter as well as in the dimension of a sample held at ambient temperature can be explained by assuming incipient precipitation of Pu{sub 3}Ga. However, this ordered {zeta}-phase is also subject to radiation-induced disordering. As a result, the gallium-stabilized {delta}-phase, being metastable at ambient temperature, is driven towards thermodynamic equilibrium by radiation-enhanced diffusion of gallium and at the same time reverted back to its metastable state by radiation-induced disordering. A steady state is reached in which only a modest fraction of the gallium present is arranged in ordered {zeta}-phase regions.

  6. arsenide gallium nitride: Topics by E-print Network

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

    Lundberga,*, J. Lua , A Abstract The diffusion of indium and gallium in polycrystalline thin film Cu(In,Ga)Se2 layers has been with a larger number of vacancies, that facilitates...

  7. PROPERTIES OF Cd and Zn PARTIAL ELECTROLYTE TREATED CIGS SOLAR CELLS K. Ramanathan, F.S. Hasoon, S. Smith, A. Mascarenhas, H. Al-Thani, J. Alleman, H.S. Ullal and J. Keane

    E-Print Network [OSTI]

    Sites, James R.

    PROPERTIES OF Cd and Zn PARTIAL ELECTROLYTE TREATED CIGS SOLAR CELLS K. Ramanathan, F.S. Hasoon, SS/CIGS interface has been treated as a "non- interacting," or abrupt junction. There are a few reports [3 changes such as those mentioned above have not been adequately treated in further analysis of the junction

  8. Inhalation developmental toxicology studies: Gallium arsenide in mice and rats

    SciTech Connect (OSTI)

    Mast, T.J.; Greenspan, B.J.; Dill, J.A.; Stoney, K.H.; Evanoff, J.J.; Rommereim, R.L.

    1990-12-01T23:59:59.000Z

    Gallium arsenide is a crystalline compound used extensively in the semiconductor industry. Workers preparing solar cells and gallium arsenide ingots and wafers are potentially at risk from the inhalation of gallium arsenide dust. The potential for gallium arsenide to cause developmental toxicity was assessed in Sprague- Dawley rats and CD-1 (Swiss) mice exposed to 0, 10, 37, or 75 mg/m{sup 3} gallium arsenide, 6 h/day, 7 days/week. Each of the four treatment groups consisted of 10 virgin females (for comparison), and {approx}30 positively mated rats or {approx}24 positively mated mice. Mice were exposed on 4--17 days of gestation (dg), and rats on 4--19 dg. The day of plug or sperm detection was designated as 0 dg. Body weights were obtained throughout the study period, and uterine and fetal body weights were obtained at sacrifice (rats, 20 dg; mice, 18 dg). Implants were enumerated and their status recorded. Live fetuses were sexed and examined for gross, visceral, skeletal, and soft-tissue craniofacial defects. Gallium and arsenic concentrations were determined in the maternal blood and uterine contents of the rats (3/group) at 7, 14, and 20 dg. 37 refs., 11 figs., 30 tabs.

  9. Examination of Na-Doped Mo Sputtering for CIGS Devices: Cooperative Research and Development Final Report, CRADA Number CRD-10-375

    SciTech Connect (OSTI)

    Repins, I.

    2012-01-01T23:59:59.000Z

    This work has investigated the use of Na doped Mo (MONA) sputtering targets for use in preparing CIGS devices. The Mo:Na material is doped to about 3% Na by weight, implying that a 40 nm layer on top of the standard Mo contact contains sufficient Na to dope a 2.5 ..mu..m CIGS film. The ability to control Na doping independent of both CIGS processing conditions and adhesion is an important gain for industry and research. Manufacturers gain a route to increased manufacturability and performance, while NREL researchers gain a tightened performance distribution of devices and increased process flexibility. Our immediate partner in this work, the Climax Molybdenum Technology Center, gains validation of their product.

  10. 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim5742 www.advmat.de

    E-Print Network [OSTI]

    -generation photo- voltaics, such as copper indium gallium selenide (CIGS)[5,6] and copper zinc tin sulfide (CZTS

  11. Selenium Speciation and Management in Wet FGD Systems

    SciTech Connect (OSTI)

    Searcy, K; Richardson, M; Blythe, G; Wallschlaeger, D; Chu, P; Dene, C

    2012-02-29T23:59:59.000Z

    This report discusses results from bench- and pilot-scale simulation tests conducted to determine the factors that impact selenium speciation and phase partitioning in wet FGD systems. The selenium chemistry in wet FGD systems is highly complex and not completely understood, thus extrapolation and scale-up of these results may be uncertain. Control of operating parameters and application of scrubber additives have successfully demonstrated the avoidance or decrease of selenite oxidation at the bench and pilot scale. Ongoing efforts to improve sample handling methods for selenium speciation measurements are also discussed. Bench-scale scrubber tests explored the impacts of oxidation air rate, trace metals, scrubber additives, and natural limestone on selenium speciation in synthetic and field-generated full-scale FGD liquors. The presence and concentration of redox-active chemical species as well as the oxidation air rate contribute to the oxidation-reduction potential (ORP) conditions in FGD scrubbers. Selenite oxidation to the undesirable selenate form increases with increasing ORP conditions, and decreases with decreasing ORP conditions. Solid-phase manganese [Mn(IV)] appeared to be the significant metal impacting the oxidation of selenite to selenate. Scrubber additives were tested for their ability to inhibit selenite oxidation. Although dibasic acid and other scrubber additives showed promise in early clear liquor (sodium based and without calcium solids) bench-scale tests, these additives did not show strong inhibition of selenite oxidation in tests with higher manganese concentrations and with slurries from full-scale wet FGD systems. In bench-tests with field liquors, addition of ferric chloride at a 250:1 iron-to-selenium mass ratio sorbed all incoming selenite to the solid phase, although addition of ferric salts had no impact on native selenate that already existed in the field slurry liquor sample. As ORP increases, selenite may oxidize to selenate more rapidly than it sorbs to ferric solids. Though it was not possible to demonstrate a decrease in selenium concentrations to levels below the project�¢����s target of 50 ���µg/L during pilot testing, some trends observed in bench-scale testing were evident at the pilot scale. Specifically, reducing oxidation air rate and ORP tends to either retain selenium as selenite in the liquor or shift selenium phase partitioning to the solid phase. Oxidation air flow rate control may be one option for managing selenium behavior in FGD scrubbers. Units that cycle load widely may find it more difficult to impact ORP conditions with oxidation air flow rate control alone. Because decreasing oxidation air rates to the reaction tank showed that all �¢����new�¢��� selenium reported to the solids, the addition of ferric chloride to the pilot scrubber could not show further improvements in selenium behavior. Ferric chloride addition did shift mercury to the slurry solids, specifically to the fine particles. Several competing pathways may govern the reporting of selenium to the slurry solids: co-precipitation with gypsum into the bulk solids and sorption or co-precipitation with iron into the fine particles. Simultaneous measurement of selenium and mercury behavior suggests a holistic management strategy is best to optimize the fate of both of these elements in FGD waters. Work conducted under this project evaluated sample handling and analytical methods for selenium speciation in FGD waters. Three analytical techniques and several preservation methods were employed. Measurements of selenium speciation over time indicated that for accurate selenium speciation, it is best to conduct measurements on unpreserved, filtered samples as soon after sampling as possible. The capital and operating costs for two selenium management strategies were considered: ferric chloride addition and oxidation air flow rate control. For ferric chloride addition, as migh

  12. Application of ultrasound in solvent extraction of nickel and gallium

    SciTech Connect (OSTI)

    Pesic, B.

    1996-07-01T23:59:59.000Z

    The effects of ultrasound on the rate of solvent extraction of nickel with Lix 65N and Lix 70, and gallium with Kelex 100 were investigated. These solvent extraction systems are noted by their sluggish nature. Low frequency (20 kHz) ultrasound increased the rates of extraction of nickel by factors of four to seven. The ultrasound had no effect on the final chemical equilibrium. Gallium extraction rates were enhanced with the use of ultrasound by as much as a factor of 15. Again, the ultrasound had no effect on extraction equilibrium. For both nickel and gallium, the enhanced rates were attributed to increased interfacial surface area associated with ultrasonically induced cavitation and microdroplet formation. The stability of the microdroplets permitted intermittent application of ultrasound with corresponding decreases in ultrasonic energy requirements. The lowest energy consumption was observed with short (0.25 to 5 s) bursts of high power (41 to 61 W) ultrasonic inputs. The study also provided insight into the factors that affect the complex extraction of gallium from sodium aluminate solutions. The rate controlling step was found to be the dehydration of the gallate ion, Ga(OH)4, and the first complex formation between gallium and Kelex 100. Sodium was found to enhance the extraction rate up to a point, beyond which increased concentration was detrimental. Increasing aluminum concentration was found to slow extraction rates. Modifiers and diluents were shown to markedly affect extraction rates even without ultrasound. Ketone modifiers, particularly 2-undecanone, when used with Kermac 470B or Escaid 200 diluents enhanced extraction rates of gallium to the point that the use of ultrasound provided no additional benefits. The positive effects of ketone modifiers for the solvent extraction of gallium had not been previously reported.

  13. STAR FORMATION IN THE EXTENDED GASEOUS DISK OF THE ISOLATED GALAXY CIG 96

    SciTech Connect (OSTI)

    Espada, D.; Sabater, J.; Verdes-Montenegro, L.; Sulentic, J. [Instituto de Astrofisica de AndalucIa, CSIC, Apdo. 3004, 18080 Granada (Spain); Munoz-Mateos, J. C.; Gil de Paz, A. [Departamento de Astrofisica y CC. de la Atmosfera, Universidad Complutense de Madrid, Avda. de la Complutense, s/n, E-28040 Madrid (Spain); Boissier, S.; Athanassoula, E.; Bosma, A. [Laboratoire d'Astrophysique de Marseille, OAMP, Universite Aix-Marseille and CNRS UMR 6110, 38 rue Frederic Joliot-Curie, 13388 Marseille Cedex 13 (France); Verley, S. [Dept. de Fisica Teorica y del Cosmos, Universidad de Granada, Granada (Spain); Leon, S. [Joint ALMA Observatory/ESO, Av. Alonso de Cordova 3107, Vitacura, Santiago (Chile); Yun, M., E-mail: daniel.espada@nao.ac.jp, E-mail: despada@cfa.harvard.edu [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States)

    2011-07-20T23:59:59.000Z

    We study the Kennicutt-Schmidt star formation law and efficiency in the gaseous disk of the isolated galaxy CIG 96 (NGC 864), with special emphasis on its unusually large atomic gas (H I) disk (r{sub Hmathsci}/r{sub 25} = 3.5, r{sub 25} = 1.'85). We present deep Galaxy Evolution Explorer near- and far-UV observations, used as a recent star formation tracer, and we compare them with new, high-resolution (16''or 1.6 kpc) Very Large Array H I observations. The UV and H I maps show good spatial correlation outside the inner 1', where the H I phase dominates over H{sub 2}. Star-forming regions in the extended gaseous disk are mainly located along the enhanced H I emission within two (relatively) symmetric, giant gaseous spiral arm-like features, which emulate an H I pseudo-ring at r {approx_equal} 3'. Inside this structure, two smaller gaseous spiral arms extend from the northeast and southwest of the optical disk and connect to the previously mentioned H I pseudo-ring. Interestingly, we find that the (atomic) Kennicutt-Schmidt power-law index systematically decreases with radius, from N {approx_equal} 3.0 {+-} 0.3 in the inner disk (0.'8-1.'7) to N = 1.6 {+-} 0.5 in the outskirts of the gaseous disk (3.'3-4.'2). Although the star formation efficiency (SFE), the star formation rate per unit of gas, decreases with radius where the H I component dominates as is common in galaxies, we find that there is a break of the correlation at r = 1.5r{sub 25}. At radii 1.5r{sub 25} < r < 3.5r{sub 25}, mostly within the H I pseudo-ring structure, regions exist whose SFE remains nearly constant, SFE {approx_equal} 10{sup -11} yr{sup -1}. We discuss possible mechanisms that might be triggering the star formation in the outskirts of this galaxy, and we suggest that the constant SFE for such large radii (r > 2r{sub 25}) and at such low surface densities might be a common characteristic in extended UV disk galaxies.

  14. Process for forming pure silver ohmic contacts to N- and P-type gallium arsenide materials

    DOE Patents [OSTI]

    Hogan, S.J.

    1983-03-13T23:59:59.000Z

    Disclosed is an improved process for manufacturing gallium arsenide semiconductor devices having as its components a n-type gallium arsenide substrate layer and a p-type gallium arsenide diffused layer. The improved process comprises forming a pure silver ohmic contact to both the diffuse layer and the substrate layer wherein the n-type layer comprises a substantially low doping carrier concentration.

  15. Selenium transformation in coal mine spoils: Its environmental impact assessment

    SciTech Connect (OSTI)

    Harness, J.; Atalay, A.; Koll, K.J.; Zhang, H.; Maggon, D.

    1991-12-31T23:59:59.000Z

    The objective of this program was to conduct an environmental impact assessment study for selenium from coal mine spoils. The use of in-situ lysimetry to predict selenium speciation, transformation, and mobility under natural conditions was evaluated. The scope of the study was to construct and test field-scale lysimeter and laboratory mini-column to assess mobility and speciation of selenium in coal mine overburden and soil systems; to conduct soil and groundwater sampling throughout the state of Oklahoma for an overall environmental impact assessment of selenium; and to conduct an in-depth literature review on the solubility, speciation, mobility, and toxicity of selenium from various sources. Groundwater and surface soil samples were also collected from each county in Oklahoma. Data collected from the lysimeter study indicated that selenium in the overburden of the abandoned mine site was mainly found in the selenite form. The amount of selenite found was too low and immobile to be of concern to the environment. The spoil had equilibrated long enough (over 50 years) that most of the soluble forms of selenium have already been lost. Examination of the overburden indicated the presence of pyrite crystals that precipitated over time. The laboratory mini-column study indicated that selenite is quite immobile and remained on the overburden material even after leaching with dilute acid. Data from groundwater samples indicated that based on the current permissible level for selenium in groundwater (0.01 mg Se/L), Oklahoma groundwater is widely contaminated with the element. However, according to the new regulation (0.05 mg Se/L), which is to be promulgated in 1992, only 9 of the 77 counties in the state exceed the limit.

  16. Trajectory-Oriented and Fault-Tolerant-Based Intelligent Process Control for Flexible CIGS PV Module Manufacturing; Final Technical Report, 13 May 2002--30 May 2005

    SciTech Connect (OSTI)

    Simpson, L.; Britt, J.; Birkmire, R.; Vincent, T.

    2005-10-01T23:59:59.000Z

    ITN Energy Systems, Inc., and Global Solar Energy, Inc., assisted by NREL's PV Manufacturing R&D program, have continued to advance CIGS production technology by developing trajectory-oriented predictive/control models, fault-tolerance control, control platform development, in-situ sensors, and process improvements. Modeling activities included developing physics-based and empirical models for CIGS and sputter-deposition processing, implementing model-based control, and applying predictive models to the construction of new evaporation sources and for control. Model-based control is enabled by implementing reduced or empirical models into a control platform. Reliability improvement activities include implementing preventive maintenance schedules; detecting failed sensors/equipment and reconfiguring to tinue processing; and systematic development of fault prevention and reconfiguration strategies for the full range of CIGS PV production deposition processes. In-situ sensor development activities have resulted in improved control and indicated the potential for enhanced process status monitoring and control of the deposition processes. Substantial process improvements have been made, including significant improvement in CIGS uniformity, thickness control, efficiency, yield, and throughput. In large measure, these gains have been driven by process optimization, which in turn have been enabled by control and reliability improvements due to this PV Manufacturing R&D program.

  17. Interaction of a Liquid Gallium Jet with ISTTOK Edge Plasmas

    SciTech Connect (OSTI)

    Gomes, R. B.; Fernandes, H.; Silva, C.; Pereira, T.; Figueiredo, J.; Carvalho, B.; Soares, A.; Duarte, P.; Varandas, C. [Associacao EURATOM/IST, Centro de Fusao Nuclear, Av. Rovisco Pais, 1049-001 Lisboa, Porugal (Portugal); Sarakovskis, A.; Lielausis, O.; Klyukin, A.; Platacis, E.; Tale, I. [Association EURATOM/University of Latvia, Institute of Solid State Physics, 8 Kengaraga Str., LV-1063 Riga (Latvia)

    2008-04-07T23:59:59.000Z

    The use of liquid metals as plasma facing components in tokamaks has recently experienced a renewed interest stimulated by their advantages in the development of a fusion reactor. Liquid metals have been proposed to solve problems related to the erosion and neutronic activation of solid walls submitted to high power loads allowing an efficient heat exhaust from fusion devices. Presently the most promising candidate materials are lithium and gallium. However, lithium has a short liquid state range when compared, for example, with gallium that has essentially better thermal properties and lower vapor pressure. To explore further these properties, ISTTOK tokamak is being used to test the interaction of a free flying, fully formed liquid gallium jet with the plasma. The interacting, 2.3 mm diameter, jet is generated by hydrostatic pressure and has a 2.5 m/s flow velocity. The liquid metal injector has been build to allow the positioning of the jet inside the tokamak chamber, within a 13 mm range. This paper presents the first obtained experimental results concerning the liquid gallium jet-plasma interaction. A stable jet has been obtained, which was not noticeably affected by the magnetic field transients. ISTTOK has been successfully operated with the gallium jet without degradation of the discharge or a significant plasma contamination by liquid metal. This observation is supported by spectroscopic measurements showing that gallium radiation is limited to the region around the jet. Furthermore, the power deposited on the jet has been evaluated at different radial locations and the surface temperature increase estimated.

  18. Effect Threshold for Selenium Toxicity in Juvenile Splittail, Pogonichthys macrolepidotus A

    E-Print Network [OSTI]

    Rigby, Mark C.; Deng, Xin; Grieb, Thomas M.; Teh, Swee J.; Hung, Silas S.

    2010-01-01T23:59:59.000Z

    total maximum daily load (TMDL) for selenium is under development (San Francisco Bay Regional Water Quality Control

  19. Speciation of selenium in stream insects using X-ray absorption spectroscopy

    SciTech Connect (OSTI)

    Ruwandi Andrahennadi; Mark Wayland; Ingrid J. Pickering [University of Saskatchewan, Saskatoon, SK (Canada). Department of Geological Sciences

    2007-11-15T23:59:59.000Z

    Selenium contamination in the environment is a widespread problem affecting insects and other wildlife. Insects occupy a critical middle link and aid in trophic transfer of selenium in many terrestrial and freshwater food chains, but the mechanisms of selenium uptake through the food chain are poorly understood. In particular, biotransformation of selenium by insects into different chemical forms will greatly influence how toxic or benign the selenium is to that organism or to its predators. We have used X-ray absorption spectroscopy (XAS) to identify the chemical form of selenium in insects inhabiting selenium contaminated streams near Hinton, Alberta (Canada). Selenium K near-edge spectra indicate a variability of selenium speciation among the insects that included mayflies (Ephemeroptera), stoneflies (Plecoptera), caddisflies (Trichoptera), and craneflies (Diptera). Higher percentages of inorganic selenium were observed in primary consumers, detritivores, and filter feeders than in predatory insects. Among the organic forms of selenium, organic selenides constituted a major fraction in most organisms. A species modeled as trimethylselenonium was observed during the pupal stage of caddisflies. These results provide insights into how the insects cope with their toxic cargo, including how the selenium is biotransformed into less toxic forms and how it can be eliminated from the insects. More broadly, this study demonstrates the strengths of XAS to probe the effects of heavy elements at trace levels in insects from the field.

  20. Hydrological and geochemical investigations of selenium behavior at Kesterson Reservoir

    SciTech Connect (OSTI)

    Benson, S.M.; Tokunaga, T.K.; Zawislanski, P.; Yee, A.W.; Daggett, J.S.; Oldfather, J.M.; Tsao, L.; Johannis, P.W.

    1990-10-01T23:59:59.000Z

    From 1985 to the present we have studied the behavior of selenium in various habitats and environments at Kesterson reservoir, shifting emphasis as remedial actions altered the physical setting. Investigations have evaluated the efficacy of several remedial alternatives, from innovative techniques relying on the complex geochemical behavior of selenium alternatives, from innovative techniques relying on the complex geochemical behavior of selenium in aquatic environments to conventional excavation schemes. Results of these studies supported two cost-effective remedial measures; drain water deliveries were terminated in 1986 and, in 1988, 1 million cubic yards of soil were imported and used to fill the low lying areas of the former Kesterson Reservoir. To date, these two actions appear to have eliminated the aquatic habitat that caused waterfowl death and deformity at Kesterson from the early 1980's to 1987. Biological, surface water and groundwater monitoring data collected by the USBR indicate that Kesterson is now a much safer environment than in past years when drainage water containing 300{mu}g/l of selenium was delivered to the Reservoir. The continued presence of a large inventory of selenium within the upper portions of unfilled areas of Kesterson Reservoir and immediately below the fill material requires that a continued awareness of the status of this inventory be maintained and improved upon. 83 refs., 130 figs., 19 tabs.

  1. Pair distribution function study on compression of liquid gallium

    SciTech Connect (OSTI)

    Luo, Shengnian [Los Alamos National Laboratory; Yu, Tony [SUNY-SB; Chen, Jiuhua [SUNY-SB; Ehm, Lars [SUNY-SB; Guo, Quanzhong [SUNY-SB; Parise, John [SUNY-SB

    2008-01-01T23:59:59.000Z

    Integrating a hydrothermal diamond anvil cell (HDAC) and focused high energy x-ray beam from the superconductor wiggler X17 beamline at the National Synchrotron Light Source (NSLS) at the Brookhaven National Laboratory (BNL), we have successfully collected high quality total x-ray scattering data of liquid gallium. The experiments were conducted at a pressure range from 0.1GPa up to 2GPa at ambient temperature. For the first time, pair distribution functions (PDF) for liquid gallium at high pressure were derived up to 10 {angstrom}. Liquid gallium structure has been studied by x-ray absorption (Di Cicco & Filipponi, 1993; Wei et al., 2000; Comez et al., 2001), x-ray diffraction studies (Waseda & Suzuki, 1972), and molecular dynamics simulation (Tsay, 1993; Hui et al., 2002). These previous reports have focused on the 1st nearest neighbor structure, which tells us little about the atomic arrangement outside the first shell in non- crystalline materials. This study focuses on the structure of liquid gallium and the atomic structure change due to compression. The PDF results show that the observed atomic distance of the first nearest neighbor at 2.78 {angstrom} (first G(r) peak and its shoulder at the higher Q position) is consistent with previous studies by x-ray absorption (2.76 {angstrom}, Comez et al., 2001). We have also observed that the first nearest neighbor peak position did not change with pressure increasing, while the farther peaks positions in the intermediate distance range decreased with pressure increasing. This leads to a conclusion of the possible existence of 'locally rigid units' in the liquid. With the addition of reverse Monte Carlo modeling, we have observed that the coordination number in the local rigit unit increases with pressure. The bulk modulus of liquid gallium derived from the volume compression curve at ambient temperature (300K) is 12.1(6) GPa.

  2. Self- and zinc diffusion in gallium antimonide

    SciTech Connect (OSTI)

    Nicols, Samuel Piers

    2002-03-26T23:59:59.000Z

    The technological age has in large part been driven by the applications of semiconductors, and most notably by silicon. Our lives have been thoroughly changed by devices using the broad range of semiconductor technology developed over the past forty years. Much of the technological development has its foundation in research carried out on the different semiconductors whose properties can be exploited to make transistors, lasers, and many other devices. While the technological focus has largely been on silicon, many other semiconductor systems have applications in industry and offer formidable academic challenges. Diffusion studies belong to the most basic studies in semiconductors, important from both an application as well as research standpoint. Diffusion processes govern the junctions formed for device applications. As the device dimensions are decreased and the dopant concentrations increased, keeping pace with Moore's Law, a deeper understanding of diffusion is necessary to establish and maintain the sharp dopant profiles engineered for optimal device performance. From an academic viewpoint, diffusion in semiconductors allows for the study of point defects. Very few techniques exist which allow for the extraction of as much information of their properties. This study focuses on diffusion in the semiconductor gallium antimonide (GaSb). As will become clear, this compound semiconductor proves to be a powerful one for investigating both self- and foreign atom diffusion. While the results have direct applications for work on GaSb devices, the results should also be taken in the broader context of III-V semiconductors. Results here can be compared and contrasted to results in systems such as GaAs and even GaN, indicating trends within this common group of semiconductors. The results also have direct importance for ternary and quaternary semiconductor systems used in devices such as high speed InP/GaAsSb/InP double heterojunction bipolar transistors (DHBT) [Dvorak, (2001)]. Many of the findings which will be reported here were previously published in three journal articles. Hartmut Bracht was the lead author on two articles on self-diffusion studies in GaSb [Bracht, (2001), (2000)], while this report's author was the lead author on Zn diffusion results [Nicols, (2001)]. Much of the information contained herein can be found in those articles, but a more detailed treatment is presented here.

  3. (Data in kilograms of gallium content, unless noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 1995. Two companies in

    E-Print Network [OSTI]

    : No domestic primary gallium recovery was reported in 1995. Two companies in Oklahoma and Utah recovered devices, which include light-emitting diodes (LED's), laser diodes, photodetectors, and solar cells contract to a consortium of private companies to develop gallium nitride technology. Blue LED's are useful

  4. (Data in kilograms of gallium content, unless otherwise noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 2002. Two companies in

    E-Print Network [OSTI]

    and Use: No domestic primary gallium recovery was reported in 2002. Two companies in Oklahoma and Utah diodes, photodetectors, and solar cells. Integrated circuits represented 65% of gallium demand forecasts of market growth, several companies were consolidating, reducing, or eliminating their Ga

  5. E-Print Network 3.0 - arsenide- gallium instrument Sample Search...

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

    Materials Science 5 Formation of etch pits during carbon doping of gallium arsenide with carbon tetrachloride by metalorganic vapor-phase epitaxy Summary: Formation of etch pits...

  6. Nanosecond dynamics of a gallium mirror's light-induced reflectivity change

    E-Print Network [OSTI]

    V. Albanis; S. Dhanjal; V. I. Emelyanov; V. A. Fedotov; K. F. MacDonald; P. Petropoulos; D. J. Richardson; N. I. Zheludev

    2000-10-05T23:59:59.000Z

    Transient pump-probe optical reflectivity measurements of the nano/microsecond dynamics of a fully reversible, light-induced, surface-assisted metallization of gallium interfaced with silica are reported. The metallization leads to a considerable increase in the interface's reflectivity when solid a-gallium is on the verge of melting. The reflectivity change was found to be a cumulative effect that grows with light intensity and pulse duration. The reflectivity relaxes back to that of alpha-gallium when the excitation is withdrawn in a time that increases critically at gallium's melting point. The effect is attributed to a non-thermal light-induced structural phase transition.

  7. Exploration of Novel Reaction Pathway for Formation of Copper Indium Gallium Diselenide: Cooperative Research and Development Final Report, CRADA Number CRD-03-121

    SciTech Connect (OSTI)

    van Hest, M.

    2014-11-01T23:59:59.000Z

    The investigation will explore a potentially low-cost method of forming CIGS for use in solar cells. Investigators from HelioVolt will work in NREL laboratories to modify and apply our tools in fabrication of the CIGS layer. Investigators from NREL will assist in preparing substrates and in compleing solar cells composed of these CIGS layers to evaluate the effectiveness of the HelioVolt processes.

  8. JV Task 96 - Phase 2 - Investigating the Importance of the Mercury-Selenium Interaction

    SciTech Connect (OSTI)

    Nicholas Ralston; Laura Raymond

    2008-03-01T23:59:59.000Z

    In order to improve the understanding of the mercury issue, it is vital to study mercury's effects on selenium physiology. While mercury present in the environment or food sources may pose health risks, the protective effects of selenium have not been adequately considered in establishing regulatory policy. Numerous studies report that vulnerability to mercury toxicity is inversely proportional to selenium status or level. However, selenium status has not been considered in the development of the reference dosage levels for mercury exposure. Experimental animals fed low-selenium diets are far more vulnerable to mercury toxicity than animals fed normal selenium, and animals fed selenium-rich diets are even more resistant. Selenium-dependent enzymes in brain and endocrine tissues can be impaired by excessive mercury exposure, apparently because mercury has an extremely high binding affinity for selenium. When selenium becomes bound to mercury, it is unable to participate in the metabolic cycling of selenoprotein synthesis. Because of mercury-dependent impairments of selenoprotein synthesis, various antioxidant and regulatory functions in brain biochemistry are compromised. This report details a 2-year multiclient-funded research program designed to examine the interactions between mercury and selenium in animal models. The studies explored the effects of dietary intakes of toxic amounts of methylmercury and the protective effects of the normal dietary range of selenium in counteracting mercury toxicity. This study finds that the amounts of selenium present in ocean fish are sufficient to protect against far larger quantities of methylmercury than those present in typical seafoods. Toxic effects of methylmercury exposure were not directly proportional to mercury concentrations in blood, brain, or any other tissues. Instead, mercury toxicity was proportional to molar ratios of mercury relative to selenium. In order to accurately assess risk associated with methylmercury or mercury exposures, mercury-selenium ratios appear to be far more accurate and effective in identifying risk and protecting human and environmental health. This study also finds that methylmercury toxicity can be effectively treated by dietary selenium, preventing the death and progressive disabilities that otherwise occur in methylmercury-treated subjects. Remarkably, the positive response to selenium therapy was essentially equivalent regardless of whether or not toxic amounts of methylmercury were still administered. The findings of the Physiologically Oriented Integration of Nutrients and Toxins (POINT) models of the effects of mercury and selenium developed in this project are consistent with the hypothesis that mercury toxicity arises because of mercury-dependent inhibition of selenium availability in brain and endocrine tissues. This appears to occur through synergistic effects of mercury-dependent inhibition of selenium transport to these tissues and selective sequestration of the selenium present in the tissues. Compromised transport of selenium to the brain and endocrine tissues would be particularly hazardous to the developing fetus because the rapidly growing tissues of the child have no selenium reserves. Therefore, maternal consumption of foods with high mercury-selenium ratios is hazardous. In summation, methylmercury exposure is unlikely to cause harm in populations that eat selenium-rich diets but may cause harm among populations that consume certain foods that have methylmercury present in excess of selenium.

  9. Original article Effects of selenium and vitamin E

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    significativement (P mine E (58-83 %). L'âge aux and maintenance of preg- nancy and the regulation of hormone metabolism through the anterior lobe of the pituitary in vitamin E and/or selenium-supplemented ewes. How- ever, no report is available on the sparing effect

  10. Indium-Gallium Segregation in CuIn$_{x}$Ga$_{1-x}$Se$_2$: An ab initio based Monte Carlo Study

    E-Print Network [OSTI]

    Ludwig, Christian D R; Felser, Claudia; Schilling, Tanja; Windeln, Johannes; Kratzer, Peter

    2010-01-01T23:59:59.000Z

    Thin-film solar cells with CuIn$_x$Ga$_{1-x}$Se$_2$ (CIGS) absorber are still far below their efficiency limit, although lab cells reach already 19.9%. One important aspect is the homogeneity of the alloy. Large-scale simulations combining Monte Carlo and density functional calculations show that two phases coexist in thermal equilibrium below room temperature. Only at higher temperatures, CIGS becomes more and more a homogeneous alloy. A larger degree of inhomogeneity for Ga-rich CIGS persists over a wide temperature range, which may contribute to the low observed efficiency of Ga-rich CIGS solar cells.

  11. Cost and Reliability Improvement for CIGS-Based PV on Flexible Substrate: May 24, 2006 -- July 31, 2010

    SciTech Connect (OSTI)

    Wiedeman, S.

    2011-05-01T23:59:59.000Z

    Global Solar Energy rapidly advances the cost and performance of commercial thin-film CIGS products using roll-to-roll processing on steel foil substrate in compact, low cost deposition equipment, with in-situ sensors for real-time intelligent process control. Substantial increases in power module efficiency, which now exceed 13%, are evident at GSE factories in two countries with a combined capacity greater than 75 MW. During 2009 the average efficiency of cell strings (3780 cm2) was increased from 7% to over 11%, with champion results exceeding 13% Continued testing of module reliability in rigid product has reaffirmed extended life expectancy for standard glass product, and has qualified additional lower-cost methods and materials. Expected lifetime for PV in flexible packages continues to increase as failure mechanisms are elucidated, and resolved by better methods and materials. Cost reduction has been achieved through better materials utilization, enhanced vendor and material qualification and selection. The largest cost gains have come as a result of higher cell conversion efficiency and yields, higher processing rates, greater automation and improved control in all process steps. These improvements are integral to this thin film PV partnership program, and all realized with the 'Gen2' manufacturing plants, processes and equipment.

  12. Synthesis and microstructure of gallium phosphide nanowires W. S. Shi, Y. F. Zheng, N. Wang,a)

    E-Print Network [OSTI]

    Zheng, Yufeng

    Synthesis and microstructure of gallium phosphide nanowires W. S. Shi, Y. F. Zheng, N. Wang,a) C. S May 2001 Gallium phosphide GaP nanowires of 22 nm in diameter and hundreds micrometers in length were synthesized by laser ablation of a powder mixture of GaP and gallium oxide (Ga2O3 . The morphology

  13. IEEE JOURNAL OF PHOTOVOLTAICS, VOL. 2, NO. 2, APRIL 2012 123 Gallium Arsenide Solar Cell Absorption

    E-Print Network [OSTI]

    Grandidier, Jonathan

    IEEE JOURNAL OF PHOTOVOLTAICS, VOL. 2, NO. 2, APRIL 2012 123 Gallium Arsenide Solar Cell Absorption--Gallium arsenide, nanospheres, photovoltaic systems, whispering gallery modes (WGMs). I. INTRODUCTION THE route as the active layer is thinned [2]. Thin-film photovoltaics offer the possibility to significantly reduce

  14. Two-photon photovoltaic effect in gallium arsenide Jeff Chiles,1

    E-Print Network [OSTI]

    Fathpour, Sasan

    Two-photon photovoltaic effect in gallium arsenide Jichi Ma,1 Jeff Chiles,1 Yagya D. Sharma,2 214669); published September 4, 2014 The two-photon photovoltaic effect is demonstrated in gallium; (230.0250) Optoelectronics; (040.5350) Photovoltaic; (130.4310) Nonlinear. http://dx.doi.org/10.1364/OL

  15. Synthesis and use of (polyfluoroaryl)fluoroanions of aluminum, gallium and indium

    DOE Patents [OSTI]

    Marks, Tobin J. (Evanston, IL); Chen, You-Xian (Midland, MI)

    2000-01-01T23:59:59.000Z

    Salts of (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium are described. The (polyfluoroaryl)fluoroanions have the formula [ER'R"R'"F].sup..crclbar. wherein E is aluminum, gallium, or indium, wherein F is fluorine, and wherein R', R", and R'" is each a fluorinated phenyl, fluorinated biphenyl, or fluorinated polycyclic group.

  16. Gallium/aluminum nanocomposite material for nonlinear optics and nonlinear plasmonics

    E-Print Network [OSTI]

    Zheludev, Nikolay

    Gallium/aluminum nanocomposite material for nonlinear optics and nonlinear plasmonics A. V penetration of gallium into an aluminum film. These composite films form mirrorlike interfaces with silica optics and active plasmonics. The material is a polycrystalline aluminum film on a silica sub- strate

  17. Selenium Partitioning and Food-Chain Transfer at the Salton Sea

    E-Print Network [OSTI]

    Tobin, Jennifer Marie

    2011-01-01T23:59:59.000Z

    entirely by agricultural wastewater from the Imperial,selenium in the agricultural wastewater (Frankenberger andof freshwater or agricultural wastewater that the SCH ponds

  18. E-Print Network 3.0 - amorphous selenium flat Sample Search Results

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

    on a-Se direct conversion detector Summary: ). The digital detector consists of a flat panel using the amorphous selenium technology (ANRAD Corporation... : the most promising are...

  19. EA-1686: Department of Energy Loan Guarantee to SoloPower Inc. for the Electrodeposition-based Copper indium gallium selenide (CIGS) Solar Technology Manufacturing Facility near San Jose, California

    Broader source: Energy.gov [DOE]

    EA cancelled due to a change in project scope; DOE prepared a categorical exclusion determination (8/15/11).

  20. Spectroscopy of vanadium (III) doped gallium lanthanum sulphide chalcogenide glass

    E-Print Network [OSTI]

    Hughes, M; Rutt, H; Hewak, D

    2014-01-01T23:59:59.000Z

    Vanadium doped gallium lanthanum sulphide glass (V:GLS) displays three absorption bands at 580, 730 and 1155 nm identified by photoluminescence excitation measurements. Broad photoluminescence, with a full width half maximum (FWHM) of 500 nm, is observed peaking at 1500 nm when exciting at 514, 808 and 1064 nm. The fluorescence lifetime and quantum efficiency at 300 K were measured to be 33.4 us and 4 % respectively. From the available spectroscopic data we propose the vanadium ions valence to be 3+ and be in tetrahedral coordination The results indicate potential for development of a laser or optical amplifier based on V:GLS.

  1. Fabrication of a gated gallium arsenide heterostructure resonant tunneling diode

    E-Print Network [OSTI]

    Kinard, William Brian

    1989-01-01T23:59:59.000Z

    , . ' 'CONTACT PAD' PLANAR I ZED POLYAM I DE RECTIFYI CONTACT N DBHS Pig. 2. f'utavvay vieiv of a gated gallium arsenide heterostructure resonant tunneling diode 1018 graded from 10 18 io" 10? (lightly doped) units=cm 8 ?graded from 10 to 18...FABRICATION OF A GATED GALLIL". tl ARSEXIDE HETEROSTRL CTL RF. RESONANT TF'XXELI'XG DIODE A Thesis bt ttrILLIAAI BRIA'. s KI'iARD Subnut ted to the Office of Graduate Studies of Texas AE;M Eniverstty tn partial fulfillment of the requirements...

  2. XXX TJ1100-03 April 24, 2004 20:29 Exploring the Selenium Phytoremediation Potential

    E-Print Network [OSTI]

    XXX TJ1100-03 April 24, 2004 20:29 Exploring the Selenium Phytoremediation Potential of Transgenic and E. A. H. Pilon-Smits1 QUERY SHEET Q1: Au: Please provide location of Dept. 0 #12;XXX TJ1100-03 April WORDS: selenium, Indian mustard, Brassica juncea, phytoremediation. #12;XXX TJ1100-03 April 24, 2004 20

  3. Selenium and Lung Cancer: A Quantitative Analysis of Heterogeneity in the Current

    E-Print Network [OSTI]

    California at Berkeley, University of

    Selenium and Lung Cancer: A Quantitative Analysis of Heterogeneity in the Current Epidemiological on sele- nium and lung cancer and identify sources of heterogeneity among studies. When all studies were.30). Overall, these results suggest that selenium may have some protective effect against lung cancer

  4. Layer-By-Layer Self-Assembly of CIGS Nanoparticles and Polymers for All-Solution Processable Low-Cost, High-Efficiency Solar Cells

    E-Print Network [OSTI]

    Zhou, Yaoqi

    -Cost, High-Efficiency Solar Cells Tung Ho1 , Robert Vittoe3 , Namratha Kakumanu2 , Sudhir Shrestha2-Purdue University Indianapolis (IUPUI), Indianapolis, IN 46202 Thin film solar cells made from copper indium gallium thereby affecting solar cell efficiency. This research aims to study various polymer materials to replace

  5. Analysis of Sulfur And Selenium Assimilation in 'Astragalus' Plants With Varying Capacities to Accumulate Selenium

    SciTech Connect (OSTI)

    Sors, T.G.; Ellis, D.R.; Na, G.Nam.; Lahner, B.; Lee, S.; Leustek, T.; Pickering, I.J.; Salt, D.E.; /Purdue U. /Rutgers U., Piscataway /Saskatchewan U.

    2007-08-08T23:59:59.000Z

    Several Astragalus species have the ability to hyperaccumulate selenium (Se) when growing in their native habitat. Given that the biochemical properties of Se parallel those of sulfur (S), we examined the activity of key S assimilatory enzymes ATP sulfurylase (ATPS), APS reductase (APR), and serine acetyltransferase (SAT), as well as selenocysteine methyltransferase (SMT), in eight Astragalus species with varying abilities to accumulate Se. Se hyperaccumulation was found to positively correlate with shoot accumulation of S-methylcysteine (MeCys) and Se-methylselenocysteine (MeSeCys), in addition to the level of SMT enzymatic activity. However, no correlation was observed between Se hyperaccumulation and ATPS, APR, and SAT activities in shoot tissue. Transgenic Arabidopsis thaliana overexpressing both ATPS and APR had a significant enhancement of selenate reduction as a proportion of total Se, whereas SAT overexpression resulted in only a slight increase in selenate reduction to organic forms. In general, total Se accumulation in shoots was lower in the transgenic plants overexpressing ATPS, PaAPR, and SAT. Root growth was adversely affected by selenate treatment in both ATPS and SAT overexpressors and less so in the PaAPR transgenic plants. Such observations support our conclusions that ATPS and APR are major contributors of selenate reduction in planta. However, Se hyperaccumulation in Astragalus is not driven by an overall increase in the capacity of these enzymes, but rather by either an increased Se flux through the S assimilatory pathway, generated by the biosynthesis of the sink metabolites MeCys or MeSeCys, or through an as yet unidentified Se assimilation pathway.

  6. Gallium phosphide high-temperature bipolar junction transistor

    SciTech Connect (OSTI)

    Zipperian, T.E.; Dawson, L.R.; Caffin, R.J.

    1981-03-01T23:59:59.000Z

    Preliminary results are reported on the development of a high-temperature (> 350/sup 0/C) gallium phosphide bipolar junction transistor (BJT) for goethermal and other energy applications. This four-layer p/sup +/n/sup -/pp/sup +/ structure was fromed by liquid phase epitaxy using a supercooling technique to insure uniform nucleation of the thin layers. Magnesium was used as the p-type dopant to avoid excessive out-diffusion into the lightly doped base. By appropriate choice of electrodes, the device may also be driven as an n-channel junction field-effect transistor. The gallium phosphide BJT is observed to have a common-emitter current gain peaking in the range of 6 to 10 (for temperatures from 20/sup 0/C to 400/sup 0/C) and a room-temperature, punchthrough-limited, collector-emitter breakdown voltage of approximately -6V. Other parameters of interest include an f/sub/ = 400 KHz (at 20/sup 0/C) and a collector base leakage current = 200 ..mu..A (at 350/sup 0/C).

  7. Gallium nitride microcavities formed by photoenhanced wet oxidation

    SciTech Connect (OSTI)

    Peng, L.-H.; Lu, C.-Y.; Wu, W.-H.; Wang, S.-L. [Department of Electrical Engineering and Institute of Electro-Optical Engineering, National Taiwan University, Taipei, Taiwan (China)

    2005-10-17T23:59:59.000Z

    We report the formation of gallium nitride (GaN) microcavities by manipulating a photoenhanced oxidation rate difference between the polar and nonpolar crystallographic planes of GaN. When immersed in a buffered acetic (CH{sub 3}COOH) electrolyte of pH{approx}6.2 at room temperature, it is shown that the photo-oxidation can proceed at a rate that is one order of magnitude slower on the nonpolar plane of {l_brace}1100{r_brace}{sub GaN} than on the polar plane of {l_brace}0001{r_brace}{sub GaN} due to the reduced surface field action. Gallium nitride microcavities bounded by optically smooth {l_brace}1100{r_brace} and {l_brace}1103{r_brace} facets can thus be preferentially formed on the c-plane sapphire substrate after dissolving the oxide layer. The optical properties of these GaN hexagonal cavities reveal characteristic peaks of whispering gallery modes in resonance with the GaN band edge emission spectrum. A typical cavity Q factor of 10{sup 3} is observed in these GaN microcavities due to a reduced optical scattering loss in the wet chemical reaction process.

  8. Specific interaction of fluoride ions with aluminum and gallium solvates in an ethylene glycol solutions

    SciTech Connect (OSTI)

    Petrosyants, S.P.; Tsabel', E.R.; Buslaev, Yu.A.

    1986-01-01T23:59:59.000Z

    The interaction of aluminum chloride and gallium chloride with KF in ethylene glycol solutions with F:M/sup 3 +/ mole ratios approximately equal to 2 includes a step involving the formation of fluorine-containing species, in which the fluoride ions are held in the outer sphere of ethylene glycol solvates of aluminum and gallium. Complexes based on hexacoordinate solvates predominate in the solutions of aluminum, while in the case of gallium, in contrast to aluminum, the coexistence of tetra- and hexacoordinate complexes is characteristic. The configurational equilibrium in the solutions of gallium is one of the causes of the structurization of the solutions, i.e., polymerization due to the formation of H bonds between the fluoride ions and the coordinated ethylene glycol molecules.

  9. Luminescence dynamics and waveguide applications of europium doped gallium nitride powder

    E-Print Network [OSTI]

    Lipson, Michal

    Luminescence dynamics and waveguide applications of europium doped gallium nitride powder Carl B, bismuth shot, and europium ingot in an ammonia ambient to initially obtain chunks of the desired material

  10. Selenium inhibits the phytotoxicity of mercury in garlic (Allium sativum)

    SciTech Connect (OSTI)

    Zhao, Jiating [CAS Key Laboratory of Nuclear Analytical Techniques, Key Lab for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)] [CAS Key Laboratory of Nuclear Analytical Techniques, Key Lab for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Gao, Yuxi, E-mail: gaoyx@ihep.ac.cn [CAS Key Laboratory of Nuclear Analytical Techniques, Key Lab for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)] [CAS Key Laboratory of Nuclear Analytical Techniques, Key Lab for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Li, Yu-Feng; Hu, Yi; Peng, Xiaomin [CAS Key Laboratory of Nuclear Analytical Techniques, Key Lab for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)] [CAS Key Laboratory of Nuclear Analytical Techniques, Key Lab for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Dong, Yuanxing [Department of Physics, Xinzhou Teachers University, Xinzhou 034000 (China)] [Department of Physics, Xinzhou Teachers University, Xinzhou 034000 (China); Li, Bai; Chen, Chunying [CAS Key Laboratory of Nuclear Analytical Techniques, Key Lab for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)] [CAS Key Laboratory of Nuclear Analytical Techniques, Key Lab for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Chai, Zhifang, E-mail: chaizf@ihep.ac.cn [CAS Key Laboratory of Nuclear Analytical Techniques, Key Lab for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)] [CAS Key Laboratory of Nuclear Analytical Techniques, Key Lab for Biomedical Effects of Nanomaterial and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

    2013-08-15T23:59:59.000Z

    To investigate the influence of selenium on mercury phytotoxicity, the levels of selenium and mercury were analyzed with inductively coupled plasma-mass spectrometry (ICP-MS) in garlic tissues upon exposure to different dosages of inorganic mercury (Hg{sup 2+}) and selenite (SeO{sub 3}{sup 2?}) or selenate (SeO{sub 4}{sup 2?}). The distributions of selenium and mercury were examined with micro-synchrotron radiation X-ray fluorescence (?-SRXRF), and the mercury speciation was investigated with micro-X-ray absorption near edge structure (?-XANES). The results show that Se at higher exposure levels (>1 mg/L of SeO{sub 3}{sup 2?} or SeO{sub 4}{sup 2?}) would significantly inhibit the absorption and transportation of Hg when Hg{sup 2+} levels are higher than 1 mg/L in culture media. SeO{sub 3}{sup 2?} and SeO{sub 4}{sup 2?} were found to be equally effective in reducing Hg accumulation in garlic. The inhibition of Hg uptake by Se correlates well with the influence of Se on Hg phytotoxicity as indicated by the growth inhibition factor. Elemental imaging using ?-SRXRF also shows that Se could inhibit the accumulation and translocation of Hg in garlic. ?-XANES analysis shows that Hg is mainly present in the forms of Hg–S bonding as Hg(GSH){sub 2} and Hg(Met){sub 2}. Se exposure elicited decrease of Hg–S bonding in the form of Hg(GSH){sub 2}, together with Se-mediated alteration of Hg absorption, transportation and accumulation, may account for attenuated Hg phytotoxicity by Se in garlic. -- Highlights: ? Hg phytotoxicity can be mitigated by Se supplement in garlic growth. ? Se can inhibit the accumulation and transportation of Hg in garlic tissues. ? Localization and speciation of Hg in garlic can be modified by Se.

  11. First Results of the Testing of the Liquid Gallium Jet Limiter Concept for ISTTOK

    SciTech Connect (OSTI)

    Gomes, R. B.; Fernandes, H.; Silva, C.; Borba, D.; Carvalho, B.; Varandas, C. [Associacao EURATOM/IST, Centro de FuSao Nuclear, Av. Rovisco Pais, 1049-001 Lisbon (Portugal); Lielausis, O.; Klyukin, A.; Platacis, E.; Mikelsons, A.; Platnieks, I. [Association EURATOM/University of Latvia, Institute of Physics, 32 Miera Str., Salaspils, LV-2169 (Latvia)

    2006-12-04T23:59:59.000Z

    The use of liquid metals as plasma facing components in tokamaks has recently experienced a renewed interest stimulated by their advantages to the development of a fusion reactor. Liquid metals have been proposed to solve problems related to the erosion and neutronic activation of solid walls submitted to high power loads allowing an efficient heat exhaustion from fusion devices. Presently the most promising materials are Lithium and Gallium. ISTTOK, a small size tokamak, will be used to test the behavior of a liquid Gallium jet in the vacuum chamber and its influence on the plasma. This paper presents a description of the conceived setup as well as experimental results. The liquid Gallium jet is generated by hydrostatic pressure and injected in a radial position close to a moveable stainless steel limiter. Both the jet and the limiter positions are variable allowing for a controlled exposure of the liquid Gallium to the edge plasma. The main components of the Gallium loop are a MHD pump, the liquid metal injector and a filtering system. The MHD pump is of the induction type, based on rotating permanent magnets. The injector is build from a stainless steel pipe ended by a shaping nozzle. A setup has been developed to introduce oxide-free Gallium inside the loop's main supply tank. Raw liquid metal is placed inside a chamber heated and degassed under high vacuum while clean Gallium is extracted from the main body of the liquefied metal. Prior to installation on the tokamak, the experimental rig has been implemented using a Pyrex tube as test chamber to investigate the stability of the Gallium jet and its break-up length for several nozzle sizes. Results are presented in this paper. This rig was also useful to assess the behavior of the overall implemented apparatus.

  12. Riley oxidation: A forgotten name reaction for synthesis of selenium nanoparticles

    SciTech Connect (OSTI)

    Shah, Chetan P.; Dwivedi, Charu; Singh, Krishan K. [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)] [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Kumar, Manmohan, E-mail: manmoku@barc.gov.in [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)] [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Bajaj, Parma N. [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)] [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

    2010-09-15T23:59:59.000Z

    A simple wet chemical method, involving reaction of acetone with selenium dioxide, has been developed, to synthesize polyvinyl alcohol-stabilized selenium nanoparticles. The method is capable of producing nanoparticles in the size range of about 100-300 nm, under ambient conditions. The synthesized nanoparticles can be separated easily from the aqueous sols by a high-speed centrifuge, and can be re-dispersed in aqueous medium by a sonicator. The effect of concentrations of selenium dioxide, acetone and PVA on the size of the selenium nanoparticles has been studied. The size of the selenium nanoparticles has been found to increase with increase in the reaction time as well as the concentration of selenium dioxide, while it decreases with increase in the concentration of the stabilizer, PVA. The synthesized selenium nanoparticles have been characterized by UV-visible optical absorption spectroscopy, X-ray diffraction, energy dispersive X-ray analysis, differential scanning calorimetry, atomic force microscopy, scanning electron microscopy and transmission electron microscopy techniques.

  13. High-Temperature Decomposition of Brřnsted Acid Sites in Gallium-Substituted Zeolites

    SciTech Connect (OSTI)

    K Al-majnouni; N Hould; W Lonergan; D Vlachos; R Lobo

    2011-12-31T23:59:59.000Z

    The dehydroxylation of Broensted acid sites (BAS) in Ga-substituted zeolites was investigated at temperatures up to 850 C using X-ray absorption spectroscopy (XAS), Fourier transform infrared spectroscopy (FTIR), and mass spectrometry-temperature programmed desorption (MS-TPD). X-ray absorption near-edge spectroscopy (XANES) revealed that the majority of gallium has tetrahedral coordination even after complete dehydroxylation. The interatomic gallium-oxygen distance and gallium coordination number determined by extended X-ray absorption fine structure (EXAFS) are consistent with gallium in tetrahedral coordination at low T (< 550 C). Upon heating Ga-Beta and Ga-ZSM5 to 850 C, analysis of the EXAFS showed that 70 and 80% of the gallium was still in tetrahedral coordination. The remainder of the gallium was found to be in octahedral coordination. No trigonal Ga atoms were observed. FTIR measurements carried out at similar temperatures show that the intensity of the OH vibration due to BAS has been eliminated. MS-TPD revealed that hydrogen in addition to water evolved from the samples during dehydroxylation. This shows that dehydrogenation in addition to dehydration is a mechanism that contributes to BAS decomposition. Dehydrogenation was further confirmed by exposing the sample to hydrogen to regenerate some of the BAS as monitored by FTIR and MS-TPD.

  14. Study of liquid gallium at high pressure using synchrotron x-ray

    SciTech Connect (OSTI)

    Yu, Tony; Guo Quanzhong; Parise, John [Department of Geosciences, Mineral Physics Institute, Stony Brook University, Stony Brook, New York 11794-2100 (United States); Chen Jiuhua [Department of Geosciences, Mineral Physics Institute, Stony Brook University, Stony Brook, New York 11794-2100 (United States); Department of Mechanical and Materials Engineering, Center for the Study of Matters at Extreme Conditions, Florida International University, Miami, Florida 33199 (United States); Ehm, Lars [Department of Geosciences, Mineral Physics Institute, Stony Brook University, Stony Brook, New York 11794-2100 (United States); National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States); Huang Shu [Department of Mechanical and Materials Engineering, Center for the Study of Matters at Extreme Conditions, Florida International University, Miami, Florida 33199 (United States); Luo Shengnian [Physics Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2012-06-01T23:59:59.000Z

    Liquid gallium has been studied at high pressure up to 2 GPa and ambient temperature in a diamond anvil cell using high energy synchrotron x-ray beam. The total x-ray scattering data of liquid gallium were collected up to Q = 12 A{sup -1} and analyzed using pair distribution functions (PDF). The results indicate that the first nearest neighbor peak and second nearest neighbor (shoulder) peak of PDF in liquid gallium does not change with pressure, whereas the higher order (i.e., third and fourth) nearest neighbor peaks shift towards shorter distance with increasing pressure. Reverse Monte Carlo modeling based on the observed data shows that the coordination number in the liquid gallium increases with pressure from 10.5 at 0.3 GPa to 11.6 at 2 GPa. An atomic arrangement similar to the crystalline phase of Ga(II) with coordination number of 12 is proposed for the locally dense-packed rigid unit in liquid gallium. The volume compression data derived from the structure modeling yield a bulk modulus of 12.1(6) GPa for liquid gallium.

  15. Study of Magnetohydrodynamic Surface Waves on Liquid Gallium

    SciTech Connect (OSTI)

    Hantao Ji; William Fox; David Pace; H.L. Rappaport

    2004-05-13T23:59:59.000Z

    Magnetohydrodynamic (MHD) surface waves on liquid gallium are studied theoretically and experimentally in the small magnetic Reynolds number limit. A linear dispersion relation is derived when a horizontal magnetic field and a horizontal electric current is imposed. No wave damping is found in the shallow liquid limit while waves always damp in the deep liquid limit with a magnetic field parallel to the propagation direction. When the magnetic field is weak, waves are weakly damped and the real part of the dispersion is unaffected, while in the opposite limit waves are strongly damped with shortened wavelengths. In a table-top experiment, planar MHD surface waves on liquid gallium are studied in detail in the regime of weak magnetic field and deep liquid. A non-invasive diagnostic accurately measures surface waves at multiple locations by reflecting an array of lasers off the surface onto a screen, which is recorded by an Intensified-CCD camera. The measured dispersion relation is consistent with the linear theory with a reduced surface tension likely due to surface oxidation. In excellent agreement with linear theory, it is observed that surface waves are damped only when a horizontal magnetic field is imposed parallel to the propagation direction. No damping is observed under a perpendicular magnetic field. The existence of strong wave damping even without magnetic field suggests the importance of the surface oxide layer. Implications to the liquid metal wall concept in fusion reactors, especially on the wave damping and a Rayleigh-Taylor instability when the Lorentz force is used to support liquid metal layer against gravity, are discussed.

  16. Hydrological and geochemical investigations of selenium behavior at Kesterson Reservoir

    SciTech Connect (OSTI)

    Zawislanski, P.T.; Tokunaga, T.K.; Benson, S.M. [Lawrence Berkeley Lab., CA (United States). Earth Sciences Div.] [and others

    1995-05-01T23:59:59.000Z

    This report describes research relevant to selenium specification, fractionation, physical redistribution, reduction and oxidation, and spatial distribution as related to Kesterson Reservoir. The work was carried out by scientists and engineers from the Earth Sciences Division of the Lawrence Berkeley Laboratory over a two year period from October 1992 to September 1994. Much of the focus of these efforts was on the effects of two above-average rainfall years (1991/1992 and 1992/1993). These events marked a departure from the previous six years of drought conditions, under which oxidation of Se in the soil profile led to a marked increase in soluble Se. Evidence from the last two years show that much of the re-oxidized Se was once more reduced due to increased soil moisture content. Also, in areas of high hydraulic conductivity, major vertical displacement of selenium and other solutes due to rainfall infiltration was observed. Such observations underscore the dependence of the future of Se speciation and distribution on environmental conditions.

  17. Design and Synthesis of Plasmonic Core/Shell Nanorods for Light Trapping in Organic Photo-Voltaics, Non-Linear Optics and Photo-Thermal Tumor Therapy

    E-Print Network [OSTI]

    Jankovic, Vladan

    2013-01-01T23:59:59.000Z

    solar cells, developed in the 1980s and based on amorphous or polycrystalline silicon (Si), copper indium gallium (di)selenide (CIGS), and

  18. By Deborah A. Kramer No primary gallium was produced in the United States in consumption were adjusted to reflect full industry coverage.

    E-Print Network [OSTI]

    that it would reopen its 50-ton-per-year gallium recovery facility in Pinjarra, Western Australia, in 1996

  19. Field-Measured Oxidation Rates of Biologically Reduced Selenium in Sludge

    E-Print Network [OSTI]

    Benson, Sally M.; Daggett, John; Zawislansi, Peter

    1999-01-01T23:59:59.000Z

    Reduced Selenium in Sludge Sally M. Benson, John Daggett andCalifornia 94720 U.S.A. Sludge generated during surface-Finding safe and economical sludge disposal methods requires

  20. The distribution of selenium and other trace elements in Texas waters and soils

    E-Print Network [OSTI]

    Jiang, Desheng

    1999-01-01T23:59:59.000Z

    Instrumental and chemical conditions for selenium analysis. . . . . . . . . . . . . . . . . . . 35 . . . 40 10 Summary of method detection limits (MDL), SRM recoveries, spike recoveries, RPD between duplicates and samples in the ICP analysis for 22...

  1. (Data in kilograms of gallium content, unless otherwise noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 1997. Two companies in

    E-Print Network [OSTI]

    and Use: No domestic primary gallium recovery was reported in 1997. Two companies in Oklahoma and Utah in optoelectronic devices, which include light-emitting diodes (LED's), laser diodes, photodetectors, and solar-than-expected increase in demand. The company planned to operate its refineries in France and Germany using stockpiled

  2. (Data in kilograms of gallium content, unless otherwise noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 1999. Two companies in

    E-Print Network [OSTI]

    and Use: No domestic primary gallium recovery was reported in 1999. Two companies in Oklahoma and Utah in optoelectronic devices, which include light-emitting diodes (LED's), laser diodes, photodetectors, and solar in July. The additional facility was expected to double the company's refinery capacity to 100

  3. Potential for selenium migration at a lignite power plant solid waste disposal facility

    E-Print Network [OSTI]

    Hall, Steven Douglas

    1986-01-01T23:59:59.000Z

    . All groundwater that recharges on the disposal site is slightly saline and flows east, probably discharging into the Gibbons Creek Reservoir. Selenium, arsenic, boron, iron, manganese, and sulfate in the lignite waste effluent exceed either EPA... ( 1975) drinking water standards or EPA (1973) recommended livestock water standards. Since the natural groundwater contains higher concentrations of selenium, iron, manganese, and sulfate than the waste effluent, only arsenic and boron should...

  4. Selenium transformation in coal mine spoils: Its environmental impact assessment. Final report

    SciTech Connect (OSTI)

    Harness, J.; Atalay, A.; Koll, K.J.; Zhang, H.; Maggon, D.

    1991-12-31T23:59:59.000Z

    The objective of this program was to conduct an environmental impact assessment study for selenium from coal mine spoils. The use of in-situ lysimetry to predict selenium speciation, transformation, and mobility under natural conditions was evaluated. The scope of the study was to construct and test field-scale lysimeter and laboratory mini-column to assess mobility and speciation of selenium in coal mine overburden and soil systems; to conduct soil and groundwater sampling throughout the state of Oklahoma for an overall environmental impact assessment of selenium; and to conduct an in-depth literature review on the solubility, speciation, mobility, and toxicity of selenium from various sources. Groundwater and surface soil samples were also collected from each county in Oklahoma. Data collected from the lysimeter study indicated that selenium in the overburden of the abandoned mine site was mainly found in the selenite form. The amount of selenite found was too low and immobile to be of concern to the environment. The spoil had equilibrated long enough (over 50 years) that most of the soluble forms of selenium have already been lost. Examination of the overburden indicated the presence of pyrite crystals that precipitated over time. The laboratory mini-column study indicated that selenite is quite immobile and remained on the overburden material even after leaching with dilute acid. Data from groundwater samples indicated that based on the current permissible level for selenium in groundwater (0.01 mg Se/L), Oklahoma groundwater is widely contaminated with the element. However, according to the new regulation (0.05 mg Se/L), which is to be promulgated in 1992, only 9 of the 77 counties in the state exceed the limit.

  5. (Polyfluoroaryl) fluoroanions of aluminum, gallium, and indium of enhanced utility, uses thereof, and products based thereon

    DOE Patents [OSTI]

    Marks, Tobin J. (Evanston, IL); Chen, You-Xian (Midland, MI)

    2002-01-01T23:59:59.000Z

    The (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium are novel weakly coordinating anions which are highly fluorinated. (Polyfluoroaryl)fluoroanions of one such type contain at least one ring substituent other than fluorine. These (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium have greater solubility in organic solvents, or have a coordinative ability essentially equal to or less than that of the corresponding (polyfluoroaryl)fluoroanion of aluminum, gallium, or indium in which the substituent is replaced by fluorine. Another type of new (polyfluoroaryl)fluoroanion of aluminum, gallium, and indium have 1-3 perfluorinated fused ring groups and 2-0 perfluorophenyl groups. When used as a cocatalyst in the formation of novel catalytic complexes with d- or f-block metal compounds having at least one leaving group such as a methyl group, these anions, because of their weak coordination to the metal center, do not interfere in the ethylene polymerization process, while affecting the propylene process favorably, if highly isotactic polypropylene is desired. Thus, the (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium of this invention are useful in various polymerization processes such as are described.

  6. (Polyfluoroaryl) fluoroanions of aluminum, gallium, and indium of enhanced utility, uses thereof, and products based thereon

    DOE Patents [OSTI]

    Marks, Tobin J. (Evanston, IL); Chen, You-Xian (Midland, MI)

    2001-01-01T23:59:59.000Z

    The (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium are novel weakly coordinating anions which are highly fluorinated. (Polyfluoroaryl)fluoroanions of one such type contain at least one ring substituent other than fluorine. These (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium have greater solubility in organic solvents, or have a coordinative ability essentially equal to or less than that of the corresponding (polyfluoroaryl)fluoroanion of aluminum, gallium, or indium in which the substituent is replaced by fluorine. Another type of new (polyfluoroaryl)fluoroanion of aluminum, gallium, and indium have 1-3 perfluorinated fused ring groups and 2-0 perfluorophenyl groups. When used as a cocatalyst in the formation of novel catalytic complexes with d- or f-block metal compounds having at least one leaving group such as a methyl group, these anions, because of their weak coordination to the metal center, do not interfere in the ethylene polymerization process, while affecting the propylene process favorably, if highly isotactic polypropylene is desired. Thus, the (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium of this invention are useful in various polymerization processes such as are described.

  7. The design, construction, and testing of a nuclear fuel rod thermal simulation system to study gallium/Zircaloy interactions

    E-Print Network [OSTI]

    Allison, Christopher Curtis

    1999-01-01T23:59:59.000Z

    The presence of gallium in weapons grade plutonium has raised many questions concerning its use in light water reactor (LWR) fuel rods. The biggest concern is that the gallium will migrate down the thermal gradient in the fuel rod and deposit...

  8. 2011 Minerals Yearbook U.S. Department of the Interior

    E-Print Network [OSTI]

    Cs) and optoelectronic devices [laser diodes, light-emitting diodes (lEDs), photodetectors, and solar cells]. Gallium solar energy systems by about 75%, and thereby allow copper-indium-gallium diselenide (CiGS) solar

  9. Some effects of selenium on the growth and survival of larval stages of the american oyster, Crassostrea virginica

    E-Print Network [OSTI]

    Smith, Wendy S

    1979-01-01T23:59:59.000Z

    -seleniferous areas, selenium 1s present in detectable amounts: in Oregon, Had?-:i- markos and Bonhorst (1961) reported a selenium content of . 317 ppm in eggs and . 034 ppm in milk, with sim1lar figures being reported for products from other areas. In b1rds... that selenium is accumu!ated to re'latively h1gh levels in marine biota (Robertson et al. , 1972; Sandholm et al. , 1973), Recent reports indicate that . 1-. 5 pg/1 of selenium may be considered a representative range for polluted vdaters (Fowler...

  10. Electron backscatter diffraction of plutonium-gallium alloys

    SciTech Connect (OSTI)

    Boehlert, C. J. (Carl J.); Zocco, T. G. (Thomas G.); Schulze, R. K. (Roland K.); Mitchell, J. N. (Jeremy N.); Pereyra, R. A. (Ramiro A.)

    2002-01-01T23:59:59.000Z

    At Los Alamos National Laboratory a recent experimental technique has been developed to characterize reactive metals, including plutonium arid cerium, using electron backscatter diffraction (EBSD). Microstructural characterization of plutonium and its alloys by EBSD had been previously elusive primarily because of the extreme toxicity and rapid surface oxidation rate associated with plutonium metal. The experimental techniques, which included ion-sputtering the metal surface using a scanning auger microprobe (SAM) followed by vacuum transfer of the sample from the SAM to the scanning electron microscope (SEM), used to obtain electron backscatter diffraction Kikuchi patterns (EBSPs) and orientation maps for plutonium-gallium alloys are described and the initial microstructural observations based on the analysis are discussed. Combining the SEM and EBSD observations, the phase transformation behavior between the {delta} and {var_epsilon} structures was explained. This demonstrated sample preparation and characterization technique is expected to be a powerful means to further understand phase transformation behavior, orientation relationships, and texlure in the complicated plutonium alloy systems.

  11. Crystal chemistry and self-lubricating properties of monochalcogenides gallium selenide and tin selenide

    SciTech Connect (OSTI)

    Erdemir, A.

    1993-02-01T23:59:59.000Z

    This paper describes the fundamentals of the crystal chemistry and self-lubricating mechanisms of two monochalcogenides; tin selenide and gallium selenide. Specifically, it enumerates their inter-atomic array and bond structure in crystalline states, and correlates this fundamental knowledge with their self-lubricating capacity. Friction tests assessing the self-lubricating performance of gallium and tin selenides were carried out on a pin-on-disk machine. Specifically, large crystalline pieces of gallium selenide and tin selenide were cut and cleaved into flat squares and subsequently rubbed against the sapphire balls. In another case, the fine powders (particle size {approx} 50--100 {mu}m) of gallium selenide and tin selenide were manually fed into the sliding interfaces of 440C pins and 440C disks. For the specific test conditions explored, it was found that the friction coefficients of the sapphire/gallium selenide and sapphire/tin selenide pairs were {approx} 0.23 and {approx} 0.35, respectively. The friction coefficients of 440C pin/440C disk test pairs with gallium selenide and tin selenide powders were on the orders of {approx} 0.22 and {approx} 0.38, respectively. For comparison, a number of parallel friction tests were performed with MoS{sub 2} powders and compacts and the results of these tests were also reported. The friction data together with the crystal-chemical knowledge and the electron microscopic evidence supported the conclusion that the lubricity and self-lubricating mechanisms of these solids are closely related to their crystal chemistry and the nature of interlayer bonding.

  12. Results of the Gallium-Clad Phase 3 and Phase 4 tasks (canceled prior to completion)

    SciTech Connect (OSTI)

    Morris, R.N.

    1998-08-01T23:59:59.000Z

    This report summarizes the results of the Gallium-Clad interactions Phase 3 and 4 tasks. Both tasks were to involve examining the out-of-pile stability of residual gallium in short fuel rods with an imposed thermal gradient. The thermal environment was to be created by an electrical heater in the center of the fuel rod and coolant flow on the rod outer cladding. Both tasks were canceled due to difficulties with fuel pellet fabrication, delays in the preparation of the test apparatus, and changes in the Fissile Materials Disposition program budget.

  13. Percolation of gallium dominates the electrical resistance of focused ion beam deposited metals

    SciTech Connect (OSTI)

    Faraby, H. [Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093 (United States); DiBattista, M. [Qualcomm Technologies Incorporated, San Diego, California 92121 (United States); Bandaru, P. R., E-mail: pbandaru@ucsd.edu [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California 92093 (United States)

    2014-04-28T23:59:59.000Z

    Metal deposition through focused ion beam (FIB) based systems is thought to result in material composed of the primary metal from the metallo-organic precursor in addition to carbon, oxygen, and gallium. We determined, through electrical resistance and chemical composition measurements on a wide range of FIB deposited platinum and tungsten lines, that the gallium ion (Ga{sup +}) concentration in the metal lines plays the dominant role in controlling the electrical resistivity. Effective medium theory, based on McLachlan's formalisms, was used to describe the relationship between the Ga{sup +} concentration and the corresponding resistivity.

  14. In vitro bio-functionality of gallium nitride sensors for radiation biophysics

    SciTech Connect (OSTI)

    Hofstetter, Markus [Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, D-85764 Neuherberg (Germany)] [Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, D-85764 Neuherberg (Germany); Howgate, John [Walter Schottky Institut, Technische Universitaet Muenchen, Am Coulombwall 3, D-85748 Garching (Germany)] [Walter Schottky Institut, Technische Universitaet Muenchen, Am Coulombwall 3, D-85748 Garching (Germany); Schmid, Martin [Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, D-85764 Neuherberg (Germany)] [Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, D-85764 Neuherberg (Germany); Schoell, Sebastian; Sachsenhauser, Matthias [Walter Schottky Institut, Technische Universitaet Muenchen, Am Coulombwall 3, D-85748 Garching (Germany)] [Walter Schottky Institut, Technische Universitaet Muenchen, Am Coulombwall 3, D-85748 Garching (Germany); Adiguezel, Denis [Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, D-85764 Neuherberg (Germany)] [Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, D-85764 Neuherberg (Germany); Stutzmann, Martin; Sharp, Ian D. [Walter Schottky Institut, Technische Universitaet Muenchen, Am Coulombwall 3, D-85748 Garching (Germany)] [Walter Schottky Institut, Technische Universitaet Muenchen, Am Coulombwall 3, D-85748 Garching (Germany); Thalhammer, Stefan, E-mail: stefan.thalhammer@helmholtz-muenchen.de [Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, D-85764 Neuherberg (Germany)] [Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, D-85764 Neuherberg (Germany)

    2012-07-27T23:59:59.000Z

    Highlights: Black-Right-Pointing-Pointer Gallium nitride based sensors show promising characteristics to monitor cellular parameters. Black-Right-Pointing-Pointer Cell growth experiments reveal excellent biocompatibiltiy of the host GaN material. Black-Right-Pointing-Pointer We present a biofunctionality assay using ionizing radiation. Black-Right-Pointing-Pointer DNA repair is utilized to evaluate material induced alterations in the cellular behavior. Black-Right-Pointing-Pointer GaN shows no bio-functional influence on the cellular environment. -- Abstract: There is an increasing interest in the integration of hybrid bio-semiconductor systems for the non-invasive evaluation of physiological parameters. High quality gallium nitride and its alloys show promising characteristics to monitor cellular parameters. Nevertheless, such applications not only request appropriate sensing capabilities but also the biocompatibility and especially the biofunctionality of materials. Here we show extensive biocompatibility studies of gallium nitride and, for the first time, a biofunctionality assay using ionizing radiation. Analytical sensor devices are used in medical settings, as well as for cell- and tissue engineering. Within these fields, semiconductor devices have increasingly been applied for online biosensing on a cellular and tissue level. Integration of advanced materials such as gallium nitride into these systems has the potential to increase the range of applicability for a multitude of test devices and greatly enhance sensitivity and functionality. However, for such applications it is necessary to optimize cell-surface interactions and to verify the biocompatibility of the semiconductor. In this work, we present studies of mouse fibroblast cell activity grown on gallium nitride surfaces after applying external noxa. Cell-semiconductor hybrids were irradiated with X-rays at air kerma doses up to 250 mGy and the DNA repair dynamics, cell proliferation, and cell growth dynamics of adherent cells were compared to control samples. The impact of ionizing radiation on DNA, along with the associated cellular repair mechanisms, is well characterized and serves as a reference tool for evaluation of substrate effects. The results indicate that gallium nitride does not require specific surface treatments to ensure biocompatibility and suggest that cell signaling is not affected by micro-environmental alterations arising from gallium nitride-cell interactions. The observation that gallium nitride provides no bio-functional influence on the cellular environment confirms that this material is well suited for future biosensing applications without the need for additional chemical surface modification.

  15. THE EFFECT OF ORGANIC SELENIUM SUPPLEMENTATION AND DIETARY ENERGY MANIPULATION ON MARES AND THEIR FOALS: SELENIUM CONCENTRATIONS, GLUTATHIONE PEROXIDASE ACTIVITY, FOALING PARAMETERS AND FOAL PHYSICAL CHARACTERISTICS

    E-Print Network [OSTI]

    Karren, Brady

    2010-01-16T23:59:59.000Z

    Quarter Horse mares (n=28, 465-612 kg BW, 6-19 yrs of age) were used to investigate the effect of organic selenium (Se) supplementation (Selenosource, Diamond V Mills, Inc. Cedar Rapids, IA (SeM)) and DE manipulation on plasma, muscle, and colostrum...

  16. Millimeter wave ferromagnetic resonance in gallium-substituted ?-iron oxide

    SciTech Connect (OSTI)

    Chao, Liu, E-mail: liu.chao@tufts.edu; Afsar, Mohammed N. [Department of Electrical and Computer Engineering, Tufts University, Medford, Massachusetts 02155 (United States); Ohkoshi, Shin-ichi [Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2014-05-07T23:59:59.000Z

    In millimeter wave frequency range, hexagonal ferrites with high uniaxial anisotropic magnetic fields are used as absorbers. These ferrites include M-type barium ferrite (BaFe{sub 12}O{sub 19}) and strontium ferrite (SrFe{sub 12}O{sub 19}), which have natural ferromagnetic resonant frequency range from 40 GHz to 60?GHz. However, the higher frequency range lacks suitable materials that support the higher frequency ferromagnetic resonance. A new series of gallium-substituted ?-iron oxides (?-Ga{sub x}Fe{sub 2?x}O{sub 3}) are synthesized which have ferromagnetic resonant frequencies appearing over the frequency range 30 GHz–150 GHz. The ?-Ga{sub x}Fe{sub 2?x}O{sub 3} is synthesized by the combination of reverse micelle and sol-gel techniques or the sol-gel method only. The particle sizes are observed to be smaller than 100 nm. In this paper, the free space magneto-optical approach has been employed to study these newly developed ?-Ga{sub x}Fe{sub 2?x}O{sub 3} particles in millimeter waves. This technique enables to obtain precise transmission spectra to determine the dielectric and magnetic properties of both isotropic and anisotropic ferrites in the millimeter wave frequency range from a single set of direct measurements. The transmittance and absorbance spectra of ?-Ga{sub x}Fe{sub 2?x}O{sub 3} are shown in this paper. Strong ferromagnetic resonances at different frequencies determined by the x parameter are found.

  17. Gallium-cladding compatibility testing plan: Phase 3 -- Test plan for centrally heated surrogate rodlet test. Revision 2

    SciTech Connect (OSTI)

    Morris, R.N.; Baldwin, C.A.; Wilson, D.F.

    1998-07-01T23:59:59.000Z

    The Fissile Materials Disposition Program (FMDP) is investigating the use of weapons grade plutonium in mixed oxide (MOX) fuel for light-water reactors (LWR). Commercial MOX fuel has been successfully used in overseas reactors for many years; however, weapons derived fuel may differ from the previous commercial fuels because of small amounts of gallium impurities. A concern presently exists that the gallium may migrate out of the fuel, react with and weaken the clad, and thereby promote loss of fuel pin integrity. Phases 1 and 2 of the gallium task are presently underway to investigate the types of reactions that occur between gallium and clad materials. This is a Level-2 document as defined in the Fissile Materials Disposition Program Light-Water Reactor Mixed-Oxide Fuel Irradiation Test Project Plan. This Plan summarizes the projected Phase 3 Gallium-Cladding compatibility heating test and the follow-on post test examination (PTE). This work will be performed using centrally-heated surrogate pellets, to avoid unnecessary complexities and costs associated with working with plutonium and an irradiation environment. Two sets of rodlets containing pellets prepared by two different methods will be heated. Both sets will have an initial bulk gallium content of approximately 10 ppm. The major emphasis of the PTE task will be to examine the material interactions, particularly indications of gallium transport from the pellets to the clad.

  18. Development and modeling of iron-gallium alloys Rick Allen Kellogg

    E-Print Network [OSTI]

    Flatau, Alison B.

    Development and modeling of iron-gallium alloys by Rick Allen Kellogg A dissertation submitted APPENDIX C: POISSON'S RATIOS OF Fe-Al ALLOYS 154 REFERENCES 155 #12;iv ACKNOWLEDGEMENTS Many people deserve University and the Department of Aerospace Engineering and Engineering Mechanics for providing academic

  19. May 20, 2010 Growing gallium arsenide in thick multilayer stacks could make a big

    E-Print Network [OSTI]

    Rogers, John A.

    of photovoltaics and optoelectronic devices such as near-infrared (NIR) imagers looks set to become significantly material systems such as gallium nitride and indium phosphide (Nature 465 329). "We can generate compound of substrates, including glass and plastic. In photovoltaics, we expect the cost reductions to be significant

  20. Optical, electrical, and solar energy-conversion properties of gallium arsenide nanowire-array

    E-Print Network [OSTI]

    Zhou, Chongwu

    Optical, electrical, and solar energy-conversion properties of gallium arsenide nanowire, and will aid in the design and optimization of nanowire-based systems for solar energy-conversion applications, and the photoelectrochemical energy-conversion properties of GaAs nanowire arrays were evaluated in contact with one

  1. ELECTRON MICROPROBE AND PHOTOLUMINESCENCE ANALYSIS OF EUROPIUM-DOPED GALLIUM NITRIDE LIGHT EMITTERS

    E-Print Network [OSTI]

    Strathclyde, University of

    ELECTRON MICROPROBE AND PHOTOLUMINESCENCE ANALYSIS OF EUROPIUM-DOPED GALLIUM NITRIDE LIGHT EMITTERSN-on-sapphire epilayers implanted with Europium ions, producing characteristic red emission lines between 540 and 680 nm with energies largely independent of the host material. For example, doping with europium, erbium and thulium

  2. Preconceptual design for separation of plutonium and gallium by ion exchange

    SciTech Connect (OSTI)

    DeMuth, S.F.

    1997-09-30T23:59:59.000Z

    The disposition of plutonium from decommissioned nuclear weapons, by incorporation into commercial UO{sub 2}-based nuclear reactor fuel, is a viable means to reduce the potential for theft of excess plutonium. This fuel, which would be a combination of plutonium oxide and uranium oxide, is referred to as a mixed oxide (MOX). Following power generation in commercial reactors with this fuel, the remaining plutonium would become mixed with highly radioactive fission products in a spent fuel assembly. The radioactivity, complex chemical composition, and large size of this spent fuel assembly, would make theft difficult with elaborate chemical processing required for plutonium recovery. In fabricating the MOX fuel, it is important to maintain current commercial fuel purity specifications. While impurities from the weapons plutonium may or may not have a detrimental affect on the fuel fabrication or fuel/cladding performance, certifying the effect as insignificant could be more costly than purification. Two primary concerns have been raised with regard to the gallium impurity: (1) gallium vaporization during fuel sintering may adversely affect the MOX fuel fabrication process, and (2) gallium vaporization during reactor operation may adversely affect the fuel cladding performance. Consequently, processes for the separation of plutonium from gallium are currently being developed and/or designed. In particular, two separation processes are being considered: (1) a developmental, potentially lower cost and lower waste, thermal vaporization process following PuO{sub 2} powder preparation, and (2) an off-the-shelf, potentially higher cost and higher waste, aqueous-based ion exchange (IX) process. While it is planned to use the thermal vaporization process should its development prove successful, IX has been recommended as a backup process. This report presents a preconceptual design with material balances for separation of plutonium from gallium by IX.

  3. Selenium(IV) and (VI) sorption by soils surrounding fly ash management facilities

    SciTech Connect (OSTI)

    Hyun, S.; Burns, P.E.; Murarka, I.; Lee, L.S. [Purdue University, West Lafayette, IN (United States)

    2006-11-15T23:59:59.000Z

    Leachate derived from unlined coal ash disposal facilities is one of the most significant anthropogenic sources of selenium to the environment. To establish a practical framework for predicting transport of selenium in ash leachate, sorption of Se(IV) and Se(VI) from 1 mM CaSO{sub 4} was measured for 18 soils obtained down-gradient from three ash landfill sites and evaluated with respect to several soil properties. Furthermore, soil attenuation from lab-generated ash leachate and the effect of Ca{sup 2+} and SO{sub 4}{sup 2-} concentrations as well as pH on both Se(IV) and Se(VI) was quantified for a subset of soils. For both Se(IV) and Se(VI), pH combined with either percentage clay or dithionite-citrate-bicarbonate (DCB)-extractable Fe described {gt} 80% of the differences in sorption across all soils, yielding an easy approach for making initial predictions regarding site-specific selenium transport to sensitive water bodies. Se(IV) consistently exhibited an order of magnitude greater sorption than Se(VI). Selenium sorption was highest at lower pH values, with Se(IV) sorption decreasing at pH values above 6, whereas Se(VI) decreased over the entire pH range (2.5-10). Using these pH adsorption envelopes, the likely effect of ash leachate-induced changes in soil pore water pH with time on selenium attenuation by down gradient soils can be predicted. Selenium sorption increased with increasing Ca{sup 2+} concentrations while SO{sub 4}2- suppressed sorption well above enhancements by Ca{sup 2+}. Soil attenuation of selenium from ash leachates agreed well with sorption measured from 1 mM CaSO{sub 4}, indicating that 1 mM CaSO{sub 4} is a reasonable synthetic leachate for assessing selenium behavior at ash landfill sites.

  4. Selenium Biotransformations in an Engineered Aquatic Ecosystem for Bioremediation of Agricultural Wastewater via Brine Shrimp

    E-Print Network [OSTI]

    Selenium Biotransformations in an Engineered Aquatic Ecosystem for Bioremediation of Agricultural Wastewater via Brine Shrimp Production Radomir Schmidt,, Prapakorn Tantoyotai, Sirine C. Fakra, Matthew A, Saskatchewan S7N 5E2, Canada United States Department of Agriculture, Agricultural Research Service, SJVASC

  5. Speciation and Attenuation of Arsenic and Selenium at Coal Combustion By-Product Management Facilities

    SciTech Connect (OSTI)

    K. Ladwig

    2005-12-31T23:59:59.000Z

    The overall objective of this project was to evaluate the impact of key constituents captured from power plant air streams (principally arsenic and selenium) on the disposal and utilization of coal combustion products (CCPs). Specific objectives of the project were: (1) to develop a comprehensive database of field leachate concentrations at a wide range of CCP management sites, including speciation of arsenic and selenium, and low-detection limit analyses for mercury; (2) to perform detailed evaluations of the release and attenuation of arsenic species at three CCP sites; and (3) to perform detailed evaluations of the release and attenuation of selenium species at three CCP sites. Each of these objectives was accomplished using a combination of field sampling and laboratory analysis and experimentation. All of the methods used and results obtained are contained in this report. For ease of use, the report is subdivided into three parts. Volume 1 contains methods and results for the field leachate characterization. Volume 2 contains methods and results for arsenic adsorption. Volume 3 contains methods and results for selenium adsorption.

  6. Selenium in Oklahoma ground water and soil. Quarterly report No. 6

    SciTech Connect (OSTI)

    Atalay, A.; Vir Maggon, D.

    1991-03-30T23:59:59.000Z

    Selenium with a consumption of 2 liters per day (5). The objectives of this study are: (1) to determine the concentrations of Se in Oklahoma ground water and soil samples. (2) to map the geographical distribution of Se species in Oklahoma. (3) to relate groundwater depth, pH and geology with concentration of Se.

  7. Selenium Accumulation, Distribution, and Speciation in Spineless Prickly Pear Cactus: A Drought-and

    E-Print Network [OSTI]

    Selenium Accumulation, Distribution, and Speciation in Spineless Prickly Pear Cactus: A Drought.H. Pilon-Smits, and John L. Freeman2 Agricultural Research Service, United States Department of Agriculture published report of these detrimental effects, which have also occurred in other Se-rich areas (Ohlendorf et

  8. ORIGINAL PAPER Liver and kidney concentrations of selenium in wild boars

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ORIGINAL PAPER Liver and kidney concentrations of selenium in wild boars (Sus scrofa) from in wild boars from the northwest part of Poland, depending on season of the year, age, sex, and body weight. Altogether, samples of livers and kidneys from 172 wild boars that were shot in 2005­2008 were

  9. Exploring the structural basis for selenium/mercury antagonism in Allium fistulosum

    SciTech Connect (OSTI)

    McNear, Jr., David H.; Afton, Scott E.; Caruso, Joseph A. (UCIN); (Kentucky)

    2012-12-10T23:59:59.000Z

    While continuing efforts are devoted to studying the mutually protective effect of mercury and selenium in mammals, few studies have investigated the mercury-selenium antagonism in plants. In this study, we report the metabolic fate of mercury and selenium in Allium fistulosum (green onion) after supplementation with sodium selenite and mercuric chloride. Analysis of homogenized root extracts via capillary reversed phase chromatography coupled with inductively coupled plasma mass spectrometry (capRPLC-ICP-MS) suggests the formation of a mercury-selenium containing compound. Micro-focused synchrotron X-ray fluorescence mapping of freshly excised roots show Hg sequestered on the root surface and outlining individual root cells, while Se is more evenly distributed throughout the root. There are also discrete Hg-only, Se-only regions and an overall strong correlation between Hg and Se throughout the root. Analysis of the X-ray absorption near edge structure (XANES) spectra show a 'background' of methylselenocysteine within the root with discrete spots of SeO{sub 3}{sup 2-}, Se{sup 0} and solid HgSe on the root surface. Mercury outlining individual root cells is possibly binding to sulfhydryl groups or plasma membrane or cell wall proteins, and in some places reacting with reduced selenium in the rhizosphere to form a mercury(II) selenide species. Together with the formation of the root-bound mercury(II) selenide species, we also report on the formation of cinnabar (HgS) and Hg{sup 0} in the rhizosphere. The results presented herein shed light on the intricate chemical and biological processes occurring within the rhizosphere that influence Hg and Se bioavailability and will be instrumental in predicting the fate and assisting in the remediation of these metals in the environment and informing whether or not fruit and vegetable food selection from aerial plant compartments or roots from plants grown in Hg contaminated soils, are safe for consumption.

  10. Osteomyelitis and infarction in sickle cell hemoglobinopathies: differentiation by combined technetium and gallium scintigraphy

    SciTech Connect (OSTI)

    Amundsen, T.R.; Siegel, M.J.; Siegel, B.A.

    1984-12-01T23:59:59.000Z

    Clinical records and scintigrams were reviewed of 18 patients with sickle cell hemoglobinophaties who had undergone combined technetium and gallium scintigraphy during 22 separate episodes of suspected osseous infection. The combined scintigrams were correctly interpreted as indicating osteomyelitis in four studies. Of 18 studies in patients with infarction, the combined scintigrams were correctly interpreted in 16 and showed either no local accumulation of Ga-67 or less accumulation than that of Tc-99m MDP at symptomatic sites. In the other two studies, the scintigrams were falsely interpreted as indicating osteomyelitis and showed congruent, increased accumulation of both Tc-99, MDP and Ga-67. This pattern must be considered indeterminate. Overall, the results indicate that the combination of technetium and gallium scintigraphy is an effective means to distinguish osteomyelitis from infarction in patients with sickle cell hemoglobinopathies.

  11. Fast neutron scattering on Gallium target at 14.8 MeV

    E-Print Network [OSTI]

    R. Han; R. Wada; Z. Chen; Y. Nie; X. Liu; S. Zhang; P. Ren; B. Jia; G. Tian; F. Luo; W. Lin; J. Liu; F. Shi; M. Huang; X. Ruan; J. Ren; Z. Zhou; H. Huang; J. Bao; K. Zhang; B. Hu

    2014-11-03T23:59:59.000Z

    Benchmarking of evaluated nuclear data libraries was performed for $\\sim 14.8$ MeV neutrons on Gallium targets. The experiments were performed at China Institute of Atomic Energy(CIAE). Solid samples of natural Gallium (3.2 cm and 6.4 cm thick) were bombarded by $\\sim 14.8$ MeV neutrons and leakage neutron energy spectra were measured at 60$^{\\circ}$ and 120$^{\\circ}$. The measured spectra are rather well reproduced by MCNP-4C simulations with the CENDL-3.1, ENDF/B-VII and JENDL-4.0 evaluated nuclear data libraries, except for the inelastic contributions around $E_{n} = 10-13$ MeV. All three libraries significantly underestimate the inelastic contributions. The inelastic contributions are further studied, using the Talys simulation code and the experimental spectra are reproduced reasonably well in the whole energy range by the Talys calculation, including the inelastic contributions.

  12. Distinctive Signature of Indium Gallium Nitride Quantum Dot Lasing in Microdisks Cavities

    E-Print Network [OSTI]

    Woolf, Alexander; Aharanovich, Igor; Zhu, Tongtong; Niu, Nan; Wang, Danqing; Oliver, Rachel A; Hu, Evelyn L

    2014-01-01T23:59:59.000Z

    Low threshold lasers realized within compact, high quality optical cavities enable a variety of nanophotonics applications. Gallium nitride (GaN) materials containing indium gallium nitride (InGaN) quantum dots and quantum wells offer an outstanding platform to study light matter interactions and realize practical devices such as efficient light emitting diodes and nanolasers. Despite progress in the growth and characterization of InGaN quantum dots, their advantages as the gain medium in low threshold lasers have not been clearly demonstrated. This work seeks to better understand the reasons for these limitations by focusing on the simpler, limited-mode microdisk cavities, and by carrying out comparisons of lasing dynamics in those cavities using varying gain media including InGaN quantum wells, fragmented quantum wells, and a combination of fragmented quantum wells with quantum dots. For each gain medium, we utilize the distinctive, high quality (Q~5500) modes of the cavities, and the change in the highest ...

  13. Fast neutron scattering on Gallium target at 14.8 MeV

    E-Print Network [OSTI]

    Han, R; Chen, Z; Nie, Y; Liu, X; Zhang, S; Ren, P; Jia, B; Tian, G; Luo, F; Lin, W; Liu, J; Shi, F; Huang, M; Ruan, X; Ren, J; Zhou, Z; Huang, H; Bao, J; Zhang, K; Hu, B

    2014-01-01T23:59:59.000Z

    Benchmarking of evaluated nuclear data libraries was performed for $\\sim 14.8$ MeV neutrons on Gallium targets. The experiments were performed at China Institute of Atomic Energy(CIAE). Solid samples of natural Gallium (3.2 cm and 6.4 cm thick) were bombarded by $\\sim 14.8$ MeV neutrons and leakage neutron energy spectra were measured at 60$^{\\circ}$ and 120$^{\\circ}$. The measured spectra are rather well reproduced by MCNP-4C simulations with the CENDL-3.1, ENDF/B-VII and JENDL-4.0 evaluated nuclear data libraries, except for the inelastic contributions around $E_{n} = 10-13$ MeV. All three libraries significantly underestimate the inelastic contributions. The inelastic contributions are further studied, using the Talys simulation code and the experimental spectra are reproduced reasonably well in the whole energy range by the Talys calculation, including the inelastic contributions.

  14. Interaction of hydrogen with gallium vacancies in wurtzite GaN

    SciTech Connect (OSTI)

    Wright, A. F.

    2001-08-01T23:59:59.000Z

    First-principles techniques are used to investigate the interaction of hydrogen with gallium vacancies in wurtzite GaN. The calculations reveal that hydrogen can either compensate a vacancy by donating an electron to a vacancy acceptor level, or passivate the vacancy by forming a hydrogen-vacancy complex. A gallium vacancy can bind up to four hydrogen atoms, and hydrogen removal energies are computed as a function of the number of hydrogen atoms. Removal energies are found to depend strongly on Fermi level and complexes containing more than two hydrogen atoms are predicted to be unstable in n-type GaN. Hydrogen vibration frequencies are computed and compared with previously reported infrared absorption measurements for hydrogen-implanted GaN.

  15. Growth of epitaxial iron nitride ultrathin film on zinc-blende gallium nitride

    SciTech Connect (OSTI)

    Pak, J.; Lin, W.; Wang, K.; Chinchore, A.; Shi, M.; Ingram, D. C.; Smith, A. R.; Sun, K.; Lucy, J. M.; Hauser, A. J.; Yang, F. Y. [Department of Physics and Astronomy, Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, Ohio 45701 (United States); Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); Department of Physics, The Ohio State University, 191 Woodruff Avenue, Columbus, Ohio 43210 (United States)

    2010-07-15T23:59:59.000Z

    The authors report the growth of iron nitride on zinc-blende gallium nitride using molecular beam epitaxy. First, zinc-blende GaN is grown on a magnesium oxide substrate having (001) orientation; second, an ultrathin layer of FeN is grown on top of the GaN layer. In situ reflection high-energy electron diffraction is used to monitor the surface during growth, and a well-defined epitaxial relationship is observed. Cross-sectional transmission electron microscopy is used to reveal the epitaxial continuity at the gallium nitride-iron nitride interface. Surface morphology of the iron nitride, similar to yet different from that of the GaN substrate, can be described as plateau valley. The FeN chemical stoichiometry is probed using both bulk and surface sensitive methods, and the magnetic properties of the sample are revealed.

  16. Origin of color centers in the flux-grown europium gallium garnet

    SciTech Connect (OSTI)

    Aleksandrovsky, A. S.; Arkhipkin, V. G.; Bezmaternykh, L. N.; Gudim, I. A.; Krylov, A. S. [L. V. Kirensky Institute of Physics, Akademgorodok, Krasnoyarsk 660036, Russia and Siberian Federal University, Krasnoyarsk 660079 (Russian Federation); Vagizov, F. [Department of Physics, Texas A and M University, College Station, Texas 77840 (United States)

    2008-04-15T23:59:59.000Z

    Europium gallium garnet (EuGG) single crystals were grown from fluxes with various contents. Optical absorption spectra of EuGG grown from a flux containing calcium show an additional band in the ultraviolet and blue regions of the spectra as compared to the case of a calcium-free flux. Moessbauer spectra of the samples grown from the fluxes with different additives show no signs of other valence states of the europium ions except for 3+. However, they indicate changes in the crystal field due to the entrance of additive ions. The nature of the additional absorption must be the same as that for calcium-doped gadolinium gallium garnet, i.e., anion vacancies. Moessbauer isotope shifts and quadrupole splitting for EuGG are determined.

  17. Surface reconstructions of cubic gallium nitride ,,001... grown by radio frequency nitrogen plasma molecular beam epitaxy

    E-Print Network [OSTI]

    observed on c-GaN 001 , depending on the growth condi- tions and the substrate. For growth of c-GaN on Ga-rich-grown GaN 001 on MgO 001 substrate. We have deduced that these variant reconstructions are com- posed of Ga; published online 27 October 2006 Cubic GaN has been grown under gallium Ga -rich growth conditions using

  18. Gallium suboxide vapor attack on chromium, cobalt, molybdenum, tungsten and their alloys at 1200 [degrees] C

    SciTech Connect (OSTI)

    Kolman, D. G. (David G.); Taylor, T. N. (Thomas N.); Park, Y. (Youngsoo); Stan, M. (Marius); Butt, D. P. (Darryl P.); Maggiore, C. J. (Carl J.); Tesmer, Joseph R.; Havrilla, G. J. (George J.)

    2004-01-01T23:59:59.000Z

    Our prior work elucidated the failure mechanism of furnace materi als (304 SS, 316 SS, and Hastelloy C-276) exposed to gallium suboxide (Ga{sub 2}O) and/or gallium oxide (Ga{sub 2}O{sub 3}) during plutonium - gallium compound processing. Failure was hypothesized to result from concurrent alloy oxidation/Ga compound reduction followed by Ga uptake. The aim of the current work is to screen candidate replacement materials. Alloys Haynes 25 (49 Co - 20 Cr - 15 W - 10 Ni - 3 Fe - 2 Mn - 0.4 Si, wt%), 52 Mo - 48 Re (wt%), 62 W - 38 Cu (wt%), and commercially pure Cr, Co, Mo, W, and alumina were examined. Preliminary assessments of commercially pure W and Mo - Re suggest that these materials may be suitable for furnace construction. Thermodynamics calculations indicating that materials containing Al, Cr, Mn, Si, and V would be susceptible to oxidation in the presence of Ga{sub 2}O were validated by experimental results. In contrast to that reported previously, an alternate reaction mechanism for Ga uptake, which does not require concurrent alloy oxidation, controls Ga uptake for certain materials. A correlation between Ga solubility and uptake was noted.

  19. Preparation of gallium nitride surfaces for atomic layer deposition of aluminum oxide

    SciTech Connect (OSTI)

    Kerr, A. J. [Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093 (United States); Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093 (United States); Chagarov, E.; Kaufman-Osborn, T.; Kummel, A. C., E-mail: akummel@ucsd.edu [Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093 (United States); Gu, S.; Wu, J.; Asbeck, P. M. [Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093 (United States); Madisetti, S.; Oktyabrsky, S. [Department of Nanoscale Science and Engineering, University at Albany–State University of New York, Albany, New York 12222 (United States)

    2014-09-14T23:59:59.000Z

    A combined wet and dry cleaning process for GaN(0001) has been investigated with XPS and DFT-MD modeling to determine the molecular-level mechanisms for cleaning and the subsequent nucleation of gate oxide atomic layer deposition (ALD). In situ XPS studies show that for the wet sulfur treatment on GaN(0001), sulfur desorbs at room temperature in vacuum prior to gate oxide deposition. Angle resolved depth profiling XPS post-ALD deposition shows that the a-Al{sub 2}O{sub 3} gate oxide bonds directly to the GaN substrate leaving both the gallium surface atoms and the oxide interfacial atoms with XPS chemical shifts consistent with bulk-like charge. These results are in agreement with DFT calculations that predict the oxide/GaN(0001) interface will have bulk-like charges and a low density of band gap states. This passivation is consistent with the oxide restoring the surface gallium atoms to tetrahedral bonding by eliminating the gallium empty dangling bonds on bulk terminated GaN(0001)

  20. Selenium nutrition of Morone hybrids including dietary requirements, bioavailability, toxicity and effects on immune responses and disease resistance

    E-Print Network [OSTI]

    Jaramillo, Francisco , Jr

    2006-08-16T23:59:59.000Z

    enhance immunocompetence and disease resistance of HSB. In the first experiment, purified and practical diets were supplemented with ?-glucan and selenium in a factorial arrangement and fed to juvenile HSB for 6 wk followed by a S. iniae challenge...

  1. Gallium-67 complexes as radioactive markers to assess gastric and colonic transit

    SciTech Connect (OSTI)

    Bellen, J.C.; Chatterton, B.E.; Penglis, S.; Tsopelas, C. [Royal Adelaide Hospital (Australia)

    1995-03-01T23:59:59.000Z

    Constipation and gastroparesis are gastrointestinal tract disorders that can be assessed by using radioactive markers in conjunction with scintigraphic techniques. Indium-111-DTPA is the radiopharmaceutical of choice for treating colonic transit in constipated patients, but it is an expensive product and its availability has been unreliable. Indium-113m-DTPA was the tracer used in our study to determine the liquid gastric emptying rate in dual-isotope solid-liquid emptying studies, however, cessation of the {sup 113}Sn/{sup 113m}In generator production makes it unavailable. Thus, development of alternative tracers to {sup 111}In-DTPA and {sup 113m}In-DTPA was essential. Gallium-67-citrate and {sup 67}Ga-EDTA were compared to {sup 111}In-DTPA to assess their efficacy for exclusive retention in the GI tract. These markers were orally administered into rats and their three-day cumulative fecal excretion, urine excretion and carcass retention were measured. An in vitro gastric emptying model was used to determine liquid phase partitioning of {sup 113m}In-DTPA, {sup 67}Ga-citrate and {sup 67}Ga-EDTA at 37{degrees}. Gallium-67-citrate was predominantly excreted in the feces (97.2% {+-} 0.2%) after three days, with negligible urine excretion (0.1% {+-} 0.0%) and carcass retention (0.6% {+-} 0.2%). These results are analogous to those obtained for {sup 111}In-DTPA for fecal excretion (96.7% {+-} 2.6%), urine excretion (0.6% {+-} 0.0%) and retention in the carcass (0.2% {+-} 0.0%). Gallium-67-EDTA showed similar partitioning in the liquid phase of the gastric emptying model compared with {sup 113m}In-DTPA. Gallium-67-citrate is an economical and readily available alternative to {sup 111}In-DTPA as a colonic transit radiopharmaceutical. Gallium-67-EDTA is also an alternative to {sup 113m}In-DTPA for assessing liquid-phase emptying in a dual-isotope solid/liquid gastric emptying study. 17 refs., 3 figs., 2 tabs.

  2. (Polyfluoroaryl)fluoroanions of aluminum, gallium, and indium of enhanced utility, uses thereof, and products based thereon

    DOE Patents [OSTI]

    Marks, Tobin J. (Evanston, IL); Chen, You-Xian (Midland, MI)

    2001-01-01T23:59:59.000Z

    The (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium are novel weakly coordinating anions which are are highly fluorinated. (Polyfluoroaryl)fluoroanions of one such type contain at least one ring substituent other than fluorine. These (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium have greater solubility in organic solvents, or have a coordinative ability essentially equal to or less than that of the corresponding (polyfluoroaryl)fluoroanion of aluminum, gallium, or indium in which the substituent is replaced by fluorine. Another type of new (polyfluoroaryl)fluoroanion of aluminum, gallium, and indium have 1-3 perfluorinated fused ring groups and 2-0 perfluorophenyl groups. When used as a cocatalyst in the formation of novel catalytic complexes with d- or f-block metal compounds having at least one leaving group such as a methyl group, these anions, because of their weak coordination to the metal center, do not interefere in the ethylene polymerization process, while affecting the the propylene process favorably, if highly isotactic polypropylene is desired. Thus, the (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium of this invention are useful in various polymerization processes such as are described.

  3. NanoSIMS analysis of arsenic and selenium in cereal grain

    SciTech Connect (OSTI)

    Moore, Katie L.; Schröder, Markus; Lombi, Enzo; Zhao, Fang-Jie; McGrath, Steve P.; Hawkesford, Malcolm J.; Shewry, Peter R.; Grovenor, Chris R.M. (Rothamsted); (UCopenhagen); (Oxford)

    2012-09-05T23:59:59.000Z

    Cereals are an important source of selenium (Se) to humans and many people have inadequate intakes of this essential trace element. Conversely, arsenic (As) is toxic and may accumulate in rice grain at levels that pose a health risk. Knowledge of the localization of selenium and arsenic within the cereal grain will aid understanding of their deposition patterns and the impact of processes such as milling. High-resolution secondary ion mass spectrometry (NanoSIMS) was used to determine the localization of Se in wheat (Triticum aestivum) and As in rice (Oryza sativa). Combined synchrotron X-ray fluorescence (S-XRF) and NanoSIMS analysis utilized the strengths of both techniques. Selenium was concentrated in the protein surrounding the starch granules in the starchy endosperm cells and more homogeneously distributed in the aleurone cells but with Se-rich hotspots. Arsenic was concentrated in the subaleurone endosperm cells in association with the protein matrix rather than in the aleurone cells. NanoSIMS indicated that the high intensity of As identified in the S-XRF image was localized in micron-sized hotspots near the ovular vascular trace and nucellar projection. This is the first study showing subcellular localization in grain samples containing parts per million concentrations of Se and As. There is good quantitative agreement between NanoSIMS and S-XRF.

  4. Selenium And Arsenic Speciation in Fly Ash From Full-Scale Coal-Burning Utility Plants

    SciTech Connect (OSTI)

    Huggins, F.E.; Senior, C.L.; Chu, P.; Ladwig, K.; Huffman, G.P.; /Kentucky U. /Reaction Engin. Int. /Elect. Power Res. Inst., Palo Alto

    2007-07-09T23:59:59.000Z

    X-ray absorption fine structure spectroscopy has been used to determine directly the oxidation states and speciation of selenium and arsenic in 10 fly ash samples collected from full-scale utility plants. Such information is needed to assess the health risk posed by these elements in fly ash and to understand their behavior during combustion and in fly ash disposal options, such as sequestration in tailings ponds. Selenium is found predominantly as Se(IV) in selenite (SeO{sub 3}{sup 2-}) species, whereas arsenic is found predominantly as As(V) in arsenate (AsO{sub 4}{sup 3-}) species. Two distinct types of selenite and arsenate spectra were observed depending upon whether the fly ash was derived from eastern U.S. bituminous (Fe-rich) coals or from western subbituminous or lignite (Ca-rich) coals. Similar spectral details were observed for both arsenic and selenium in the two different types of fly ash, suggesting that the post-combustion behavior and capture of both of these elements are likely controlled by the same dominant element or phase in each type of fly ash.

  5. The selenium-75-homocholic acid taurine test reevaluated: combined measurement of fecal selenium-75 activity and 3 alpha-hydroxy bile acids in 211 patients

    SciTech Connect (OSTI)

    van Tilburg, A.J.; de Rooij, F.W.; van den Berg, J.W.; Kooij, P.P.; van Blankenstein, M. (Department of Internal Medicine II, University Hospital Dijkzigt, Rotterdam (Netherlands))

    1991-06-01T23:59:59.000Z

    The recommended reference values for the selenium-75-homocholic acid taurine (75SeHCAT) test, used in the analysis of chronic diarrhea, were evaluated in 211 patients by comparing simultaneous measurements of 3 alpha-hydroxy bile acids and 75Se activity in daily collected stools. An initial evaluation in 11 patients showed that the fecal collection method, which allows inspection and additional analysis of stools, was equivalent to the abdominal retention method. Selenium-75-HCAT whole-body retention half-life (WBR50) was greater than 2.8 days in less than 10% of the patients with bile acid malabsorption and less than 1.7 days in less than 10% of the normals. We recommend that a 75SeHCAT WBR50 less than 1.7 days is abnormal, a WBR50 greater than 2.8 days is normal, and a WBR50 in the range 1.7-2.8 days is equivocal, which was the case in 48% (94/195) of the patients in this study.

  6. Fabrication of optoelectronic microwave linear and ring resonators on a gallium arsenide substrate

    E-Print Network [OSTI]

    Yeh, Chun-Liang

    1993-01-01T23:59:59.000Z

    for the degree of MASTER OF SCIENCE August 1993 Major Subject: Electrical Engineering FABRICATION OF OPTOELECTRONIC MICROWAVE LINEAR AND RING RESONATORS ON A GALLIUM ARSENIDE SUBSTRATE A Thesis by CHUN-LIANG YEH Approved as to style and content by: Mark... and the first modes at 4. 87, 4. 89, 4. 91 GHz have been designed, simulated, and fabricated on a GaAs substrate. A microstrip ring resonator with 3/4 pm coupling gaps and the first mode at 3. 456 GHz also has been fabricated on GaAs. A reliable high yield...

  7. Process development for the fabrication of monolithic optoelectronic resonators on gallium arsenide substrates

    E-Print Network [OSTI]

    Fairchild, Brock Wilson

    1990-01-01T23:59:59.000Z

    with fairly good adhension prop- erties with gallium arsenide and gold. A layer of nickel was deposited on top of the AuGe to reduce the GaAs/AuGe interfacial strain that causes the AuGe to peal during plating. Good adhesion can be formed with GaAs when Au.... 57 LIST OF FIGURES FIGURE Page Typical ring resonator with coupled feed lines. Width/height ratio of photoresist in the gap region. Process steps for the fabrication of resonating structures. (a). Deposition of AuGe and nickel. (b). Spin...

  8. Bulk measurement of copper and sodium content in CuIn(0.7)Ga(0.3)Se(2) (CIGS) solar cells with nanosecond pulse length laser induced breakdown spectroscopy (LIBS)

    E-Print Network [OSTI]

    Kowalczyk, Jeremy M D; DeAngelis, Alexander; Kaneshiro, Jess; Mallory, Stewart A; Chang, Yuancheng; Gaillard, Nicolas

    2013-01-01T23:59:59.000Z

    In this work, we show that laser induced breakdown spectroscopy (LIBS) with a nanosecond pulse laser can be used to measure the copper and sodium content of CuIn(0.7)Ga(0.3)Se(2) (CIGS) thin film solar cells on molybdenum. This method has four significant advantages over methods currently being employed: the method is inexpensive, measurements can be taken in times on the order of one second, without high vacuum, and at distances up to 5 meters or more. The final two points allow for in-line monitoring of device fabrication in laboratory or industrial environments. Specifically, we report a linear relationship between the copper and sodium spectral lines from LIBS and the atomic fraction of copper and sodium measured via secondary ion mass spectroscopy (SIMS), discuss the ablation process of this material with a nanosecond pulse laser compared to shorter pulse duration lasers, and examine the depth resolution of nanosecond pulse LIBS.

  9. Dynamics of formation of photoresponse in a detector structure made of gallium arsenide

    SciTech Connect (OSTI)

    Ayzenshtat, G. I., E-mail: ayzen@mail.tomsknet.ru; Lelekov, M. A.; Tolbanov, O. P. [Tomsk State University (Russian Federation)

    2008-04-15T23:59:59.000Z

    The influence of capture effects on the characteristics of detectors of the ionizing radiation based on semi-insulating gallium arsenide is considered. Generation of nonequilibrium electrons and holes along the entire thickness of the active region was performed under illumination with an infrared light-emitting diode with a wavelength of 0.9 {mu}m. In this case, the situation emerging in the device structure under the effect of X-ray radiation or a high-energy electron beam was simulated. It is shown that the variation in the shape of the output signal with time in this case is caused by variation in the electric field profile due to the capture of holes at deep centers in gallium arsenide. An absolutely different distribution of the electric field emerges in the structure under irradiation of a semitransparent cathode of the structure with a red light-emitting diode, emission of which penetrates into the active region for mere 1 {mu}m. In this case, the transformation of the electric field is caused by the capture of electrons. Under the prolonged effect of such radiation, a space-charge-limited current mode emerges in the device.

  10. Anionic Gallium-Based Metal;#8722;Organic Framework and Its Sorption and Ion-Exchange Properties

    SciTech Connect (OSTI)

    Banerjee, Debasis; Kim, Sun Jin; Wu, Haohan; Xu, Wenqian; Borkowski, Lauren A.; Li, Jing; Parise, John B. (Kwangju); (Rutgers); (SBU)

    2012-04-30T23:59:59.000Z

    A gallium-based metal-organic framework Ga{sub 6}(C{sub 9}H{sub 3}O{sub 6}){sub 8} {center_dot} (C{sub 2}H{sub 8}N){sub 6}(C{sub 3}H{sub 7}NO){sub 3}(H{sub 2}O){sub 26} [1, Ga{sub 6}(1,3,5-BTC){sub 8} {center_dot} 6DMA {center_dot} 3DMF {center_dot} 26H{sub 2}O], GaMOF-1; BTC = benzenetricarboxylate/trimesic acid and DMA = dimethylamine, with space group I{bar 4}3d, a = 19.611(1) {angstrom}, and V = 7953.4(6) {angstrom}{sup 3}, was synthesized using solvothermal techniques and characterized by synchrotron-based X-ray microcrystal diffraction. Compound 1 contains isolated gallium tetrahedra connected by the organic linker (BTC) forming a 3,4-connected anionic porous network. Disordered positively charged ions and solvent molecules are present in the pore, compensating for the negative charge of the framework. These positively charged molecules could be exchanged with alkali-metal ions, as is evident by an ICP-MS study. The H{sub 2} storage capacity of the parent framework is moderate with a H{sub 2} storage capacity of {approx}0.5 wt % at 77 K and 1 atm.

  11. An assessment of the validity of cerium oxide as a surrogate for plutonium oxide gallium removal studies

    SciTech Connect (OSTI)

    Kolman, D.G.; Park, Y.; Stan, M.; Hanrahan, R.J. Jr.; Butt, D.P.

    1999-03-01T23:59:59.000Z

    Methods for purifying plutonium metal have long been established. These methods use acid solutions to dissolve and concentrate the metal. However, these methods can produce significant mixed waste, that is, waste containing both radioactive and chemical hazards. The volume of waste produced from the aqueous purification of thousands of weapons would be expensive to treat and dispose. Therefore, a dry method of purification is highly desirable. Recently, a dry gallium removal research program commenced. Based on initial calculations, it appeared that a particular form of gallium (gallium suboxide, Ga{sub 2}O) could be evaporated from plutonium oxide in the presence of a reducing agent, such as small amounts of hydrogen dry gas within an inert environment. Initial tests using ceria-based material (as a surrogate for PuO{sub 2}) showed that thermally-induced gallium removal (TIGR) from small samples (on the order of one gram) was indeed viable. Because of the expense and difficulty of optimizing TIGR from plutonium dioxide, TIGR optimization tests using ceria have continued. This document details the relationship between the ceria surrogate tests and those conducted using plutonia.

  12. Tripodal aminophenolate ligand complexes of aluminum(III), gallium(III), and indium(III) in water

    SciTech Connect (OSTI)

    Caravan, P.; Orvig, C. [Univ. of British Columbia, Vancouver (Canada)] [Univ. of British Columbia, Vancouver (Canada)

    1997-01-15T23:59:59.000Z

    This article focuses on the development of radiopharmaceuticals using new chelators of gallium and indium. The radionuclide kinetics and demetalation kinetics are of great consideration. This work explored the effects of ligand backbone variations on the selectivity of multidentate aminophenolate ligands among the trivalent metal ions Al(III), Ga(III) and In(III) in water. 54 refs., 16 figs., 3 tabs.

  13. Formation of etch pits during carbon doping of gallium arsenide with carbon tetrachloride by metalorganic vapor-phase epitaxy

    E-Print Network [OSTI]

    Li, Lian

    Formation of etch pits during carbon doping of gallium arsenide with carbon tetrachloride to examine the effects of carbon tetrachloride concentration and temperature on the morphology of carbon with increasing carbon tetrachloride concentration. Step bunching and pinning was observed at a IV/III ratio

  14. Simulation assisted design of a gallium phosphide np photovoltaic junction Charles R. Allen, Jong-Hyeok Jeon , Jerry M. Woodall

    E-Print Network [OSTI]

    Woodall, Jerry M.

    University, 1205 W State Street, West Lafayette, IN, USA a r t i c l e i n f o Article history: Received 27 February 2010 Keywords: Gallium phosphide Solar cell Multi-junction CPV Simulation a b s t r a c with measurements of the dark and light response. The light current was measured under an illumination of air mass

  15. Organometallic vapor-phase homoepitaxy of gallium arsenide assisted by a downstream hydrogen afterglow plasma in the growth region

    E-Print Network [OSTI]

    Collins, George J.

    Organometallic vapor-phase homoepitaxy of gallium arsenide assisted by a downstream hydrogen 1991; accepted for publication 3 April 1992) hz situ generated arsenic hydrides are reacted downstream with trimethylgallium (TMGa), both in the presence of and in the absence of a downstream hydrogen afterglow plasma. The

  16. Scanning Tunneling Microscopy and Surface Simulation of Zinc-Blende GaN(001) Intrinsic 4 Reconstruction: Linear Gallium Tetramers?

    E-Print Network [OSTI]

    Reconstruction: Linear Gallium Tetramers? Hamad A. AL-Brithen, Rong Yang, Muhammad B. Haider, Costel Constantin and occupied states, in agreement with surface simulations based on the 4 1 linear tetramer model the existence of linear Ga tetramers. DOI: PACS numbers: 68.35.Bs, 68.37.Ef, 73.20.At Based on both fundamental

  17. Some effects of selenium on the growth and survival of larval stages of the american oyster, Crassostrea virginica 

    E-Print Network [OSTI]

    Smith, Wendy S

    1979-01-01T23:59:59.000Z

    State University Chairman of Advisory Committee: Dr. J . M. Neff Acute Oioa say on early life stages of C assostre ~vi i ica indicate that selenium was toxic at all concentrations tested. Toxic effects are most significant at 10 ppm, particularly...) of the experiment. Some toxicity however, was apparent. In continuous exposures, selenium proved to be highly toxic, with effects compounded over time. Survival in 10 ppm was less than 1! after 48 hours and decreased to . 14K after 72 hours. In all...

  18. Methods for the speciation and determination of arsenic and selenium in coal combustion products

    SciTech Connect (OSTI)

    Schabron, J.F.; Hart, B.K.; Niss, N.D.; Brown, T.H.

    1991-11-01T23:59:59.000Z

    Methods of sample preparation for the determination of total selenium, and selenite, selenate, arsenite, and arsenate in coal fly ash materials were evaluated. The measurement methods use atomic spectroscopy for the determination of total concentrations and ion chromatography (IC) for the determination of individual ionic species. Sample preparation procedures which minimize the loss or alteration of the species of interest was explored and defined. The utility of the sample preparation methods can be sample dependent, so caution is advised in their use. IC conditions were established for the determination in extract solutions of selenite, selenate, arsenite, and arsenate with minimal interference from common anions.

  19. Lemly, A.D. 1995. A Protocol for Aquatic Hazard Assessment of Selenium. Ecotoxicology and Environmental Safety, Vol. 32, No. 280B288 Lemly, A.D. 1996. Assessing the Toxic Threat of Selenium to Fish and Aquatic Birds. Environmental Monitoring and Assessmen

    E-Print Network [OSTI]

    References Lemly, A.D. 1995. A Protocol for Aquatic Hazard Assessment of Selenium and Environmental Defense. The Project is subject to a Waste Discharge Requirement that strictly limits the load and the overall hazard of selenium to the ecosystem continued to be high according to Lemly's index (Lemly 1995

  20. In situ analyses on negative ions in the indium-gallium-zinc oxide sputtering process

    SciTech Connect (OSTI)

    Jia, Junjun; Torigoshi, Yoshifumi; Shigesato, Yuzo [Graduate School of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo, Sagamihara, Kanagawa 252-5258 (Japan)

    2013-07-01T23:59:59.000Z

    The origin of negative ions in the dc magnetron sputtering process using a ceramic indium-gallium-zinc oxide target has been investigated by in situ analyses. The observed negative ions are mainly O{sup -} with energies corresponding to the target voltage, which originates from the target and barely from the reactive gas (O{sub 2}). Dissociation of ZnO{sup -}, GaO{sup -}, ZnO{sub 2}{sup -}, and GaO{sub 2}{sup -} radicals also contributes to the total negative ion flux. Furthermore, we find that some sputtering parameters, such as the type of sputtering gas (Ar or Kr), sputtering power, total gas pressure, and magnetic field strength at the target surface, can be used to control the energy distribution of the O{sup -} ion flux.

  1. Origin of deep subgap states in amorphous indium gallium zinc oxide: Chemically disordered coordination of oxygen

    SciTech Connect (OSTI)

    Sallis, S.; Williams, D. S. [Materials Science and Engineering, Binghamton University, Binghamton, New York 13902 (United States); Butler, K. T.; Walsh, A. [Center for Sustainable Technologies and Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom); Quackenbush, N. F. [Department of Physics, Applied Physics, and Astronomy, Binghamton University, Binghamton, New York 13902 (United States); Junda, M.; Podraza, N. J. [Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606 (United States); Fischer, D. A.; Woicik, J. C. [Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); White, B. E.; Piper, L. F. J., E-mail: lpiper@binghamton.edu [Department of Physics, Applied Physics, and Astronomy, Binghamton University, Binghamton, New York 13902 (United States); Materials Science and Engineering, Binghamton University, Binghamton, New York 13902 (United States)

    2014-06-09T23:59:59.000Z

    The origin of the deep subgap states in amorphous indium gallium zinc oxide (a-IGZO), whether intrinsic to the amorphous structure or not, has serious implications for the development of p-type transparent amorphous oxide semiconductors. We report that the deep subgap feature in a-IGZO originates from local variations in the oxygen coordination and not from oxygen vacancies. This is shown by the positive correlation between oxygen composition and subgap intensity as observed with X-ray photoelectron spectroscopy. We also demonstrate that the subgap feature is not intrinsic to the amorphous phase because the deep subgap feature can be removed by low-temperature annealing in a reducing environment. Atomistic calculations of a-IGZO reveal that the subgap state originates from certain oxygen environments associated with the disorder. Specifically, the subgap states originate from oxygen environments with a lower coordination number and/or a larger metal-oxygen separation.

  2. Structure and electrical characterization of gallium arsenide nanowires with different V/III ratio growth parameters

    SciTech Connect (OSTI)

    Muhammad, R.; Ahamad, R. [Sustainability Research Alliance, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Ibrahim, Z.; Othaman, Z. [Physic Department, Faculty of Science, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia)

    2014-03-05T23:59:59.000Z

    Gallium arsenide (GaAs) nanowires were grown vertically on GaAs(111)B substrate by gold-assisted using metal-organic chemical vapour deposition. Field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and conductivity atomic force microscopy (CAFM) analysis were carried out to investigate the effects of V/III ratio on structural properties and current-voltage changes in the wires. Results show that GaAs NWs grow preferably in the wurtzite crystal structure than zinc blende crystal structure with increasing V/III ratio. Additionally, CAFM studies have revealed that zincblende nanowires indicate ohmic characteristic compared to oscillation current occurred for wurtzite structures. The GaAs NWs with high quality structures are needed in solar cells technology for trapping energy that directly converts of sunlight into electricity with maximum capacity.

  3. Outdoor Performance of a Thin-Film Gallium-Arsenide Photovoltaic Module

    SciTech Connect (OSTI)

    Silverman, T. J.; Deceglie, M. G.; Marion, B.; Cowley, S.; Kayes, B.; Kurtz, S.

    2013-06-01T23:59:59.000Z

    We deployed a 855 cm2 thin-film, single-junction gallium arsenide (GaAs) photovoltaic (PV) module outdoors. Due to its fundamentally different cell technology compared to silicon (Si), the module responds differently to outdoor conditions. On average during the test, the GaAs module produced more power when its temperature was higher. We show that its maximum-power temperature coefficient, while actually negative, is several times smaller in magnitude than that of a Si module used for comparison. The positive correlation of power with temperature in GaAs is due to temperature-correlated changes in the incident spectrum. We show that a simple correction based on precipitable water vapor (PWV) brings the photocurrent temperature coefficient into agreement with that measured by other methods and predicted by theory. The low operating temperature and small temperature coefficient of GaAs give it an energy production advantage in warm weather.

  4. Analysis of gallium arsenide deposition in a horizontal chemical vapor deposition reactor using massively parallel computations

    SciTech Connect (OSTI)

    Salinger, A.G.; Shadid, J.N.; Hutchinson, S.A. [and others

    1998-01-01T23:59:59.000Z

    A numerical analysis of the deposition of gallium from trimethylgallium (TMG) and arsine in a horizontal CVD reactor with tilted susceptor and a three inch diameter rotating substrate is performed. The three-dimensional model includes complete coupling between fluid mechanics, heat transfer, and species transport, and is solved using an unstructured finite element discretization on a massively parallel computer. The effects of three operating parameters (the disk rotation rate, inlet TMG fraction, and inlet velocity) and two design parameters (the tilt angle of the reactor base and the reactor width) on the growth rate and uniformity are presented. The nonlinear dependence of the growth rate uniformity on the key operating parameters is discussed in detail. Efficient and robust algorithms for massively parallel reacting flow simulations, as incorporated into our analysis code MPSalsa, make detailed analysis of this complicated system feasible.

  5. Selenium Bioaccumulation in Stocked Fish as an Indicator of Fishery Potential in Pit Lakes on Reclaimed Coal Mines

    E-Print Network [OSTI]

    Hontela, Alice

    on Reclaimed Coal Mines in Alberta, Canada L. L. Miller · J. B. Rasmussen · V. P. Palace · G. Sterling · A to selenium (Se) and other metals and metalloids in pit lakes formed by open pit coal mining in Tertiary (thermal coal) and in Cretaceous (metallurgical coal) bedrock. Juvenile hatchery rainbow trout

  6. A Prospective Study of Blood Selenium Levels and the Risk of Arsenic-2 related Premalignant Skin Lesions3

    E-Print Network [OSTI]

    van Geen, Alexander

    1 1 A Prospective Study of Blood Selenium Levels and the Risk of Arsenic-2 related Premalignant-related premalignant skin lesions and prediagnostic blood Se levels in 30357 cases of skin lesions newly-diagnosed from in the Health Effects59 of As Longitudinal Study with available baseline blood and urine samples collected in60

  7. A field-shaping multi-well avalanche detector for direct conversion amorphous selenium

    SciTech Connect (OSTI)

    Goldan, A. H.; Zhao, W. [Department of Radiology, School of Medicine, SUNY at Stony Brook, Stony Brook, New York 11794 (United States)

    2013-01-15T23:59:59.000Z

    Purpose: A practical detector structure is proposed to achieve stable avalanche multiplication gain in direct-conversion amorphous selenium radiation detectors. Methods: The detector structure is referred to as a field-shaping multi-well avalanche detector. Stable avalanche multiplication gain is achieved by eliminating field hot spots using high-density avalanche wells with insulated walls and field-shaping inside each well. Results: The authors demonstrate the impact of high-density insulated wells and field-shaping to eliminate the formation of both field hot spots in the avalanche region and high fields at the metal-semiconductor interface. Results show a semi-Gaussian field distribution inside each well using the field-shaping electrodes, and the electric field at the metal-semiconductor interface can be one order-of-magnitude lower than the peak value where avalanche occurs. Conclusions: This is the first attempt to design a practical direct-conversion amorphous selenium detector with avalanche gain.

  8. Barrier Coatings for Thin Film Solar Cells: Final Subcontract Report, September 1, 2002 -- January 30, 2008

    SciTech Connect (OSTI)

    Olsen, L. C.

    2010-03-01T23:59:59.000Z

    This program has involved investigations of the stability of CdTe and copper-indium-gallium-diselenide (CIGS) solar cells under damp heat conditions and effects of barrier coatings.

  9. Journal of Crystal Growth 310 (2008) 29872994 Reaction kinetics of CuGaSe2 formation from

    E-Print Network [OSTI]

    Anderson, Timothy J.

    2008-01-01T23:59:59.000Z

    of polycrystalline thin-film Cu(InxGa1Ŕx)Se2 (CIGS) solar cells achieved over the past several decades appears. Copper gallium diselenide; B3. Solar cells 1. Introduction The continuous improvement in the efficiency for the top cell in a CIGS tandem structure [2­4], given its suitable band gap energy (1.68 eV), process

  10. Structural and electronic properties of -In2X3 (X=O, S, Se, Te) using ab initio calculations

    E-Print Network [OSTI]

    Khare, Sanjay V.

    by NREL [1]. CdS is one of the important layers in fabricating CIGS solar cells but poses ecological and environmentally friendly copper­indium­gallium­selenide solar cells and molecules. Here we have studied been investigated. © 2011 Elsevier B.V. All rights reserved. Introduction Cu­In­Ga­S (CIGS) based solar

  11. (Data in metric tons unless otherwise noted) Domestic Production and Use: Indium was not recovered from ores in the United States in 2007. Indium-containing

    E-Print Network [OSTI]

    were exported to Canada for processing. Two companies, one in New York and the other in Rhode Island gallium diselenide (CIGS) solar cells require approximately 50 metric tons of indium to produce 1 gigawatt of solar power. Research was underway to develop a low-cost manufacturing process for flexible CIGS solar

  12. Selenium fractionation and cycling in the intertidal zone of the Carquinez Strait. Annual report, October 1, 1995--December 31,1996

    SciTech Connect (OSTI)

    Zawislanski, P.T.; McGrath, A.E.; Benson, S.M. [and others

    1997-10-01T23:59:59.000Z

    Selenium geochemistry in tidal wetlands is a topic of continuing study at Lawrence Berkeley National Laboratory. The program of studies described in this report was initiated in the fall of 1994 in response to concerns about elevated Se concentrations in waters, sediments, and biota in the Carquinez Strait. Processes by which selenium is introduced and potentially released from the sediment system have been the focus of research in 1996.

  13. Elastic properties of sulphur and selenium doped ternary PbTe alloys by first principles

    SciTech Connect (OSTI)

    Bali, Ashoka, E-mail: rcmallik@physics.iisc.ernet.in; Chetty, Raju, E-mail: rcmallik@physics.iisc.ernet.in; Mallik, Ramesh Chandra, E-mail: rcmallik@physics.iisc.ernet.in [Thermoelectric Materials and Devices Laboratory, Department of Physics, Indian Institute of Science, Bangalore-560012 (India)

    2014-04-24T23:59:59.000Z

    Lead telluride (PbTe) is an established thermoelectric material which can be alloyed with sulphur and selenium to further enhance the thermoelectric properties. Here, a first principles study of ternary alloys PbS{sub x}Te{sub (1?x)} and PbSe{sub x}Te{sub (1?x)} (0?x?1) based on the Virtual Crystal Approximation (VCA) is presented for different ratios of the isoelectronic atoms in each series. Equilibrium lattice parameters and elastic constants have been calculated and compared with the reported data. Anisotropy parameter calculated from the stiffness constants showed a slight improvement in anisotropy of elastic properties of the alloys over undoped PbTe. Furthermore, the alloys satisfied the predicted stability criteria from the elastic constants, showing stable structures, which agreed with the previously reported experimental results.

  14. High-pressure behavior of amorphous selenium from ultrasonic measurements and Raman spectroscopy

    SciTech Connect (OSTI)

    He, Z.; Liu, X. R.; Hong, S. M., E-mail: hpswjtu@gmail.com, E-mail: smhong@home.swjtu.edu.cn [Laboratory of High Pressure Physics, Southwest Jiaotong University, Key Laboratory of Advanced Technologies of Materials, Ministry of Education of China, Chengdu 610031 (China); Wang, Z. G. [National Key Laboratory for Shock Wave and Detonation Physics Research, Institute of Fluid Physics, Chinese Academy of Engineering Physics, Mianyang 621900 (China); Zhu, H. Y. [State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012 (China); Peng, J. P. [School of Physical Science and Technology, Southwest Jiaotong University, Chengdu 610031 (China)

    2014-07-07T23:59:59.000Z

    The high-pressure behavior of melt-quenched amorphous selenium (a-Se) has been investigated via ultrasonic measurements and Raman scattering at room temperature. The ultrasonic measurements were conducted on a-Se in a multi-anvil apparatus with two different sample assemblies at pressures of up to 4.5 and 4.8?GPa. We discovered that similar kinks occur in the slopes of the pressure dependence characteristics of the travel time and the sound velocity in both shear and longitudinal waves in the 2.0–2.5?GPa range. These kinks are independent of the sample assemblies, indicating an intrinsic transformation of the a-Se. Additionally, we deduced the pressure-volume relationship of a-Se from the sound velocity characteristics using the Birch–Murnaghan equation of state, and the results agreed well with those of previous reports. In situ high-pressure Raman scattering measurements of a-Se were conducted in a diamond anvil cell with an 830?nm excitation line up to a pressure of 4.3?GPa. We found that the characteristic band of a-Se at ?250?cm{sup ?1} experienced a smooth shift to a lower frequency with pressure, but a sharp slope change in the band intensity versus pressure occurred near 2.5?GPa. The results of X-ray diffraction and differential scanning calorimetry measurements indicate that the samples remain in their amorphous states after decompression. Thus, we proposed that the abnormal compression behavior of a-Se in the 2.0–2.5?GPa range can be attributed to pressure-induced local atomic reconfiguration, implying an amorphous-amorphous transition of the elementary selenium.

  15. Speciation of Selenium, Arsenic, and Zinc in Class C Fly Ash

    SciTech Connect (OSTI)

    Luo, Yun; Giammar, Daniel E.; Huhmann, Brittany L.; Catalano, Jeffrey G. (WU)

    2011-11-17T23:59:59.000Z

    A major environmental concern associated with coal fly ash is the mobilization of trace elements that may contaminate water. To better evaluate proper use of fly ash, determine appropriate disposal methods, and monitor postdisposal conditions, it is important to understand the speciation of trace elements in fly ash and their possible environmental impact. The speciation of selenium, arsenic, and zinc was determined in five representative Class C fly ash samples from combustion of sub-bituminous Powder River Basin coal using synchrotron-based X-ray absorption spectroscopy to provide an improved understanding of the mechanisms of trace element association with the fly ash. Selenium in all fly ash samples occurs predominantly as Se(IV), with the exception of one sample, in which there was a minor amount of Se(0). Se(0) is likely associated with the high content of unburned coal in the sample. Arsenic exists in the fly ash as a single phase most consistent with calcium pyroarsenate. In contrast, zinc occurs as two distinct species in the silicate glass matrix of the fly ash. This work demonstrates that residual carbon in fly ash may reduce potential Se mobility in the environment by retaining it as less soluble elemental Se instead of Se(IV). Further, this work suggests that As and Zn in Class C fly ash will display substantially different release and mobilization behaviors in aquatic environments. While As release will primarily depend upon the dissolution and hydrolysis of calcium pyroarsenate, Zn release will be controlled by the dissolution of alkaline aluminosilicate glass in the ash.

  16. Investigation on properties of ultrafast switching in a bulk gallium arsenide avalanche semiconductor switch

    SciTech Connect (OSTI)

    Hu, Long, E-mail: hulong-1226@126.com [Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi'an Jiaotong University, Xi'an 710049 (China); Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an 710024 (China); Su, Jiancang; Ding, Zhenjie; Hao, Qingsong; Yuan, Xuelin [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an 710024 (China)

    2014-03-07T23:59:59.000Z

    Properties of ultrafast switching in a bulk gallium arsenide (GaAs) avalanche semiconductor switch based on semi-insulating wafer, triggered by an optical pulse, were analyzed using physics-based numerical simulations. It has been demonstrated that when a voltage with amplitude of 5.2?kV is applied, after an exciting optical pulse with energy of 1??J arrival, the structure with thickness of 650??m reaches a high conductivity state within 110 ps. Carriers are created due to photons absorption, and electrons and holes drift to anode and cathode terminals, respectively. Static ionizing domains appear both at anode and cathode terminals, and create impact-generated carriers which contribute to the formation of electron-hole plasma along entire channel. When the electric field in plasma region increases above the critical value (?4?kV/cm) at which the electrons drift velocity peaks, a domain comes into being. An increase in carrier concentration due to avalanche multiplication in the domains reduces the domain width and results in the formation of an additional domain as soon as the field outside the domains increases above ?4?kV/cm. The formation and evolution of multiple powerfully avalanching domains observed in the simulations are the physical reasons of ultrafast switching. The switch exhibits delayed breakdown with the characteristics affected by biased electric field, current density, and optical pulse energy. The dependence of threshold energy of the exciting optical pulse on the biased electric field is discussed.

  17. Electronic passivation of silicon surfaces by thin films of atomic layer deposited gallium oxide

    SciTech Connect (OSTI)

    Allen, T. G., E-mail: thomas.allen@anu.edu.au; Cuevas, A. [Research School of Engineering, Australian National University, Canberra 0200 (Australia)

    2014-07-21T23:59:59.000Z

    This paper proposes the application of gallium oxide (Ga{sub 2}O{sub 3}) thin films to crystalline silicon solar cells. Effective passivation of n- and p-type crystalline silicon surfaces has been achieved by the application of very thin Ga{sub 2}O{sub 3} films prepared by atomic layer deposition using trimethylgallium (TMGa) and ozone (O{sub 3}) as the reactants. Surface recombination velocities as low as 6.1?cm/s have been recorded with films less than 4.5?nm thick. A range of deposition parameters has been explored, with growth rates of approximately 0.2?Ĺ/cycle providing optimum passivation. The thermal activation energy for passivation of the Si-Ga{sub 2}O{sub 3} interface has been found to be approximately 0.5?eV. Depassivation of the interface was observed for prolonged annealing at increased temperatures. The activation energy for depassivation was measured to be 1.9?eV.

  18. Gallium ion implantation greatly reduces thermal conductivity and enhances electronic one of ZnO nanowires

    SciTech Connect (OSTI)

    Xia, Minggang, E-mail: xiamg@mail.xjtu.edu.cn [Laboratory of Nanostructure and its Physics Properties, Department of Optical Information Science and Technology, Department of Applied Physics, and MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter, School of Science, Xi'an Jiaotong University, 710049 China (China); Department of Physics and Centre for Computational Science and Engineering, National University of Singapore, Singapore 117542 (Singapore); Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore); Cheng, Zhaofang; Han, Jinyun; Zhang, Shengli [Laboratory of Nanostructure and its Physics Properties, Department of Optical Information Science and Technology, Department of Applied Physics, and MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter, School of Science, Xi'an Jiaotong University, 710049 China (China); Zheng, Minrui [Department of Physics and Centre for Computational Science and Engineering, National University of Singapore, Singapore 117542 (Singapore); Sow, Chorng-Haur [Department of Physics and Centre for Computational Science and Engineering, National University of Singapore, Singapore 117542 (Singapore); National University of Singapore Nanoscience and Nanotechnology Initiative, National University of Singapore, Singapore 117542 (Singapore); Thong, John T. L. [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore); Li, Baowen [Department of Physics and Centre for Computational Science and Engineering, National University of Singapore, Singapore 117542 (Singapore); National University of Singapore Nanoscience and Nanotechnology Initiative, National University of Singapore, Singapore 117542 (Singapore); Center for Phononics and Thermal Energy Science, School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China)

    2014-05-15T23:59:59.000Z

    The electrical and thermal conductivities are measured for individual zinc oxide (ZnO) nanowires with and without gallium ion (Ga{sup +}) implantation at room temperature. Our results show that Ga{sup +} implantation enhances electrical conductivity by one order of magnitude from 1.01 × 10{sup 3} ?{sup ?1}m{sup ?1} to 1.46 × 10{sup 4} ?{sup ?1}m{sup ?1} and reduces its thermal conductivity by one order of magnitude from 12.7 Wm{sup ?1}K{sup ?1} to 1.22 Wm{sup ?1}K{sup ?1} for ZnO nanowires of 100 nm in diameter. The measured thermal conductivities are in good agreement with those in theoretical simulation. The increase of electrical conductivity origins in electron donor doping by Ga{sup +} implantation and the decrease of thermal conductivity is due to the longitudinal and transverse acoustic phonons scattering by Ga{sup +} point scattering. For pristine ZnO nanowires, the thermal conductivity decreases only two times when its diameter reduces from 100 nm to 46 nm. Therefore, Ga{sup +}-implantation may be a more effective method than diameter reduction in improving thermoelectric performance.

  19. Crystal structure and electron microprobe analyses of a lanthanum lutetium gallium garnet

    SciTech Connect (OSTI)

    Parise, J.B.; Harlow, R.L.; Shannon, R.D. (Central Research and Development Department, E. I. DuPont De Nemours and Co., Experimental Station, Wilmington, Delaware 19880-0228 (United States)); Kwei, G.H. (LANSCE, MS-H805, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)); Allik, T.H. (Science Applications International Corporation, 1710 Goodridge Dr., P.O. Box 1303, McLean, Virginia 22102 (United States)); Armstrong, J.T. (Department of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125 (United States))

    1992-09-15T23:59:59.000Z

    Single-crystal electron microprobe analysis of a lanthanum lutetium gallium garnet has resulted in a composition of La{sub 2.37}Nd{sub 0.07}Pb{sub 0.01}Lu{sub 2.54}Cr{sub 0.01} Ga{sub 3.00}O{sub 12}. This composition gives better agreement between observed and calculated total dielectric polarizabilities than previously reported compositions (La{sub 2.26--2.32}Nd{sub 0.04}Lu{sub 2.57--2.63}Ga{sub 3.07}O{sub 12} by x-ray fluorescence and La{sub 2.655}Nd{sub 0.027}Lu{sub 2.656}Ga{sub 2.655}O{sub 12} by inductively coupled plasma analyses), and does not imply the crystal-chemically improbable presence of Lu{sup 3+} in the tetrahedral site. X-ray and neutron crystal-structure analyses have confirmed that little or no Lu resides in this site.

  20. Optical waveguiding properties into porous gallium nitride structures investigated by prism coupling technique

    SciTech Connect (OSTI)

    Alshehri, Bandar; Dogheche, Elhadj, E-mail: elhadj.dogheche@univ-valenciennes.fr [Institute Electronics, Microelectronics and Nanotechnology (IEMN CNRS), University of Valenciennes, Villeneuve d'Ascq (France); Lee, Seung-Min; Kang, Jin-Ho; Ryu, Sang-Wan, E-mail: sangwan@chonnam.ac.kr [Department of Physics, Chonnam National University, Gwangju 500-757 (Korea, Republic of); Gong, Su-Hyun; Cho, Yong-Hoon [Department of Physics and KI for the NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701 (Korea, Republic of)

    2014-08-04T23:59:59.000Z

    In order to modulate the refractive index and the birefringence of Gallium Nitride (GaN), we have developed a chemical etching method to perform porous structures. The aim of this research is to demonstrate that optical properties of GaN can be tuned by controlling the pores density. GaN films are prepared on sapphire by metal organic chemical vapor deposition and the microstructure is characterized by transmission electron microscopy, and scanning electron microscope analysis. Optical waveguide experiment is demonstrated here to determine the key properties as the ordinary (n{sub 0}) and extraordinary (n{sub e}) refractive indices of etched structures. We report here the dispersion of refractive index for porous GaN and compare it to the bulk material. We observe that the refractive index decreases when the porous density p is increased: results obtained at 0.975??m have shown that the ordinary index n{sub 0} is 2.293 for a bulk layer and n{sub 0} is 2.285 for a pores density of 20%. This value corresponds to GaN layer with a pore size of 30?nm and inter-distance of 100?nm. The control of the refractive index into GaN is therefore fundamental for the design of active and passive optical devices.

  1. Optimal composition of europium gallium oxide thin films for device applications

    SciTech Connect (OSTI)

    Wellenius, P.; Muth, J. F. [Department of Electrical and Computer Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Smith, E. R. [Kratos Defense and Security Solutions, Inc., 5030 Bradford Drive, Huntsville, Alabama 35805 (United States); LeBoeuf, S. M. [Valencell, Inc., 920 Main Campus Drive, Raleigh, North Carolina 27615 (United States); Everitt, H. O. [Army Aviation and Missile RD and E Center, Redstone Arsenal, Alabama 35898 (United States) and Department of Physics, Duke University, Durham, North Carolina 27708 (United States)

    2010-05-15T23:59:59.000Z

    Europium gallium oxide (Eu{sub x}Ga{sub 1-x}){sub 2}O{sub 3} thin films were deposited on sapphire substrates by pulsed laser deposition with varying Eu content from x=2.4 to 20 mol %. The optical and physical effects of high europium concentration on these thin films were studied using photoluminescence (PL) spectroscopy, x-ray diffraction (XRD), and Rutherford backscattering spectrometry. PL spectra demonstrate that emission due to the {sup 5}D{sub 0} to {sup 7}F{sub J} transitions in Eu{sup 3+} grows linearly with Eu content up to 10 mol %. Time-resolved PL indicates decay parameters remain similar for films with up to 10 mol % Eu. At 20 mol %, however, PL intensity decreases substantially and PL decay accelerates, indicative of parasitic energy transfer processes. XRD shows films to be polycrystalline and beta-phase for low Eu compositions. Increasing Eu content beyond 5 mol % does not continue to modify the film structure and thus, changes in PL spectra and decay cannot be attributed to structural changes in the host. These data indicate the optimal doping for optoelectronic devices based on (Eu{sub x}Ga{sub 1-x}){sub 2}O{sub 3} thin films is between 5 and 10 mol %.

  2. Selenium Accumulation, Distribution, and Speciation in Spineless Prickly Pear Cactus: A Drought- and Salt-Tolerant, Selenium-Enriched Nutraceutical Fruit Crop for Biofortified Foods

    SciTech Connect (OSTI)

    Banuelos, Gary S.; Fakra, Sirine C.; Walse, Spencer S.; Marcus, Matthew A.; Yang, Soo In; Pickering, Ingrid J.; Pilon-Smits, Elizabeth A.H.; Freeman, John L.

    2011-07-01T23:59:59.000Z

    The organ-specific accumulation, spatial distribution, and chemical speciation of selenium (Se) were previously unknown for any species of cactus. We investigated Se in Opuntia ficus-indica using inductively coupled plasma mass spectrometry, microfocused x-ray fluorescence elemental and chemical mapping ({micro}XRF), Se K-edge x-ray absorption near-edge structure (XANES) spectroscopy, and liquid chromatography-mass spectrometry (LC-MS). {micro}XRF showed Se concentrated inside small conic, vestigial leaves (cladode tips), the cladode vasculature, and the seed embryos. Se K-edge XANES demonstrated that approximately 96% of total Se in cladode, fruit juice, fruit pulp, and seed is carbon-Se-carbon (C-Se-C). Micro and bulk XANES analysis showed that cladode tips contained both selenate and C-Se-C forms. Inductively coupled plasma mass spectrometry quantification of Se in high-performance liquid chromatography fractions followed by LC-MS structural identification showed selenocystathionine-to-selenomethionine (SeMet) ratios of 75:25, 71:29, and 32:68, respectively in cladode, fruit, and seed. Enzymatic digestions and subsequent analysis confirmed that Se was mainly present in a 'free' nonproteinaceous form inside cladode and fruit, while in the seed, Se was incorporated into proteins associated with lipids. {micro}XRF chemical mapping illuminated the specific location of Se reduction and assimilation from selenate accumulated in the cladode tips into the two LC-MS-identified C-Se-C forms before they were transported into the cladode mesophyll. We conclude that Opuntia is a secondary Se-accumulating plant whose fruit and cladode contain mostly free selenocystathionine and SeMet, while seeds contain mainly SeMet in protein. When eaten, the organic Se forms in Opuntia fruit, cladode, and seed may improve health, increase Se mineral nutrition, and help prevent multiple human cancers.

  3. Shear strain mediated magneto-electric effects in composites of piezoelectric lanthanum gallium silicate or tantalate and ferromagnetic alloys

    SciTech Connect (OSTI)

    Sreenivasulu, G.; Piskulich, E.; Srinivasan, G., E-mail: srinivas@oakland.edu [Physics Department, Oakland University, Rochester, Michigan 48409 (United States); Qu, P.; Qu, Hongwei [Electrical and Computer Engineering, Oakland University, Rochester, Michigan 48309 (United States); Petrov, V. M. [Institute of Electronic Information Systems, Novgorod State University, Veliky Novgorod (Russian Federation); Fetisov, Y. K. [Moscow State Technical University of Radio Engineering, Electronics and Automation, Moscow 19454 (Russian Federation); Nosov, A. P. [Institute of Metal Physics, Ural Division of Russian Academy of Sciences, 18 S. Kovalevskaya St, Ekaterinburg 620990 (Russian Federation)

    2014-07-21T23:59:59.000Z

    Shear strain mediated magneto-electric (ME) coupling is studied in composites of piezoelectric Y-cut lanthanum gallium silicate (LGS) or tantalate (LGT) and ferromagnetic Fe-Co-V alloys. It is shown that extensional strain does not result in ME effects in these layered composites. Under shear strain generated by an ac and dc bias magnetic fields along the length and width of the sample, respectively, strong ME coupling is measured at low-frequencies and at mechanical resonance. A model is discussed for the ME effects. These composites of Y-cut piezoelectrics and ferromagnetic alloys are of importance for shear strain based magnetic field sensors.

  4. A numerical simulation study of gallium-phosphide/silicon heterojunction passivated emitter and rear solar cells

    SciTech Connect (OSTI)

    Wagner, Hannes [Department of Solar Energy, Institute Solid-State Physics, Leibniz University of Hannover, Appelstr. 2, 30167 Hannover (Germany); ARC Photovoltaics Centre of Excellence, University of New South Wales (UNSW), Sydney, NSW 2052 (Australia); Ohrdes, Tobias [Institute for Solar Energy Research Hamelin (ISFH), 31860 Emmerthal (Germany); Dastgheib-Shirazi, Amir [Div. Photovoltaics, Department of Physics, University of Konstanz, 78457 Konstanz (Germany); Puthen-Veettil, Binesh; König, Dirk [ARC Photovoltaics Centre of Excellence, University of New South Wales (UNSW), Sydney, NSW 2052 (Australia); Altermatt, Pietro P. [Department of Solar Energy, Institute Solid-State Physics, Leibniz University of Hannover, Appelstr. 2, 30167 Hannover (Germany)

    2014-01-28T23:59:59.000Z

    The performance of passivated emitter and rear (PERC) solar cells made of p-type Si wafers is often limited by recombination in the phosphorus-doped emitter. To overcome this limitation, a realistic PERC solar cell is simulated, whereby the conventional phosphorus-doped emitter is replaced by a thin, crystalline gallium phosphide (GaP) layer. The resulting GaP/Si PERC cell is compared to Si PERC cells, which have (i) a standard POCl{sub 3} diffused emitter, (ii) a solid-state diffused emitter, or (iii) a high efficiency ion-implanted emitter. The maximum efficiencies for these realistic PERC cells are between 20.5% and 21.2% for the phosphorus-doped emitters (i)–(iii), and up to 21.6% for the GaP emitter. The major advantage of this GaP hetero-emitter is a significantly reduced recombination loss, resulting in a higher V{sub oc}. This is so because the high valence band offset between GaP and Si acts as a nearly ideal minority carrier blocker. This effect is comparable to amorphous Si. However, the GaP layer can be contacted with metal fingers like crystalline Si, so no conductive oxide is necessary. Compared to the conventional PERC structure, the GaP/Si PERC cell requires a lower Si base doping density, which reduces the impact of the boron-oxygen complexes. Despite the lower base doping, fewer rear local contacts are necessary. This is so because the GaP emitter shows reduced recombination, leading to a higher minority electron density in the base and, in turn, to a higher base conductivity.

  5. Real-time x-ray studies of gallium nitride nanodot formation by droplet heteroepitaxy

    SciTech Connect (OSTI)

    Wang Yiyi; Oezcan, Ahmet S.; Sanborn, Christopher; Ludwig, Karl F.; Bhattacharyya, Anirban; Chandrasekaran, Ramya; Moustakas, Theodore D.; Zhou Lin; Smith, David J. [Physics Department, Boston University, Boston, Massachusetts 02215 (United States); Department of Electrical and Computer Engineering, Boston University, Boston, Massachusetts 02215 (United States); Department of Physics, Arizona State University, Tempe, Arizona 85287, USA and School of Materials, Arizona State University, Tempe, Arizona 85287 (United States)

    2007-10-01T23:59:59.000Z

    Self-organized gallium nitride nanodots have been fabricated using droplet heteroepitaxy on c-plane sapphire by plasma-assisted molecular beam epitaxy at different substrate temperatures and Ga fluxes. Nanoscale Ga droplets were initially formed on the sapphire substrate at high temperatures by Ga deposition from an effusion cell in an ultrahigh vacuum growth chamber. Subsequently, the droplets were converted into GaN nanodots using a nitrogen plasma source. The process was monitored and controlled using real-time grazing-incidence small-angle x-ray scattering. The samples were examined postgrowth by in situ grazing incidence x-ray diffraction and reflection high-energy electron diffraction, which confirmed the epitaxial relationship between the GaN nanodots and the sapphire surface. X-ray diffraction indicated that the wurtzite phase was dominant at higher substrate temperature (710 deg. C), but a mixture of wurtzite and zinc blende phases was present at a substrate temperature of 620 deg. C. Ex situ atomic force microscopy and transmission electron microscopy analyses showed that the dot size distribution was bimodal. A thin GaN continuous layer of {approx} three monolayers thick was observed by transmission electron microscopy on the sample grown at a substrate temperature of 620 deg. C, but no such layer was observed for the substrate temperature of 710 deg. C. This suggests that there is little mobility of Ga atoms in contact with the sapphire substrate at the lower temperature so that they cannot easily diffuse to nearby droplets and instead form a thin layer covering the surface.

  6. Real-Time X-ray Studies of Gallium Nitride Nanodot Formation by Droplet Heteroepitaxy

    SciTech Connect (OSTI)

    Wang,Y.; Ozcan, A.; Sanborn, C.; Ludwig, K.; Bhattacharyya, A.; Chandrasekaran, R.; Moustakas, T.; Zhou, L.; Smith, D.

    2007-01-01T23:59:59.000Z

    Self-organized gallium nitride nanodots have been fabricated using droplet heteroepitaxy on c-plane sapphire by plasma-assisted molecular beam epitaxy at different substrate temperatures and Ga fluxes. Nanoscale Ga droplets were initially formed on the sapphire substrate at high temperatures by Ga deposition from an effusion cell in an ultrahigh vacuum growth chamber. Subsequently, the droplets were converted into GaN nanodots using a nitrogen plasma source. The process was monitored and controlled using real-time grazing-incidence small-angle x-ray scattering. The samples were examined postgrowth by in situ grazing incidence x-ray diffraction and reflection high-energy electron diffraction, which confirmed the epitaxial relationship between the GaN nanodots and the sapphire surface. X-ray diffraction indicated that the wurtzite phase was dominant at higher substrate temperature (710? C), but a mixture of wurtzite and zinc blende phases was present at a substrate temperature of 620? C. Ex situ atomic force microscopy and transmission electron microscopy analyses showed that the dot size distribution was bimodal. A thin GaN continuous layer of ? three monolayers thick was observed by transmission electron microscopy on the sample grown at a substrate temperature of 620? C, but no such layer was observed for the substrate temperature of 710? C. This suggests that there is little mobility of Ga atoms in contact with the sapphire substrate at the lower temperature so that they cannot easily diffuse to nearby droplets and instead form a thin layer covering the surface.

  7. Recycling of cadmium and selenium from photovoltaic modules and manufacturing wastes. A workshop report

    SciTech Connect (OSTI)

    Moskowitz, P.D.; Zweibel, K. [eds.

    1992-10-01T23:59:59.000Z

    Since the development of the first silicon based photovoltaic cell in the 1950`s, large advances have been made in photovoltaic material and processing options. At present there is growing interest in the commercial potential of cadmium telluride (CdTe) and copper indium diselenide (CIS) photovoltaic modules. As the commercial potential of these technologies becomes more apparent, interest in the environmental, health and safety issues associated with their production, use and disposal has also increased because of the continuing regulatory focus on cadmium and selenium. In future, recycling of spent or broken CdTe and CIS modules and manufacturing wastes may be needed for environmental, economic or political reasons. To assist industry to identify recycling options early in the commercialization process, a Workshop was convened. At this Workshop, representatives from the photovoltaic, electric utility, and nonferrous metals industries met to explore technical and institutional options for the recycling of spent CdTe and CIS modules and manufacturing wastes. This report summarizes the results of the Workshop. This report includes: (1) A discussion of the Resource Conservation and Recovery Act regulations and their potential implications to the photovoltaic industry; (2) an assessment of the needs of the photovoltaic industry from the perspective of module manufacturers and consumers; (3) an overview of recycling technologies now employed by other industries for similar types of materials; and, (4) a list of recommendation.

  8. First direct evidence of selenium deficiency in endangered Patagonian huemel deer (Hippocamelus bisulcus)

    SciTech Connect (OSTI)

    Werner T Flueck; Jo Anne M. Smith-Flueck; Bruce J Mincher; Lenny H E Winkel

    2015-01-01T23:59:59.000Z

    The prevalence of osteopathology in 57% in the endangered adult Patagonian huemul deer 31 (Hippocamelus bisulcus), malformed antler development, and general lack of recovery were 32 previously suggested to possibly be related to mineral imbalances like selenium (Se) deficiency, 33 and not to stem from fluorosis. From recent bone analyses of these diseased huemul, fluoride 34 levels averaged 58 ppm (SE=10.7), thus eliminating fluorosis as a causal factor for the 35 osteopathology reported in huemul. In contrast, when analyzing high-elevation sites commonly 36 used by extant populations, we found soils deficient in Se. Ashes from recent volcanism also 37 were very low in Se. As Se-responsive diseases in livestock have been documented in Chile, we 38 reclassified recently published Se levels in huemul and determined that 73% were deficient and 39 18% marginal. Together with these several lines of indirect evidence, we conclude that Se 40 deficiency plays a role in the lack of recovery of huemul populations.

  9. Recycling of cadmium and selenium from photovoltaic modules and manufacturing wastes

    SciTech Connect (OSTI)

    Moskowitz, P.D.; Zweibel, K. (eds.)

    1992-01-01T23:59:59.000Z

    Since the development of the first silicon based photovoltaic cell in the 1950's, large advances have been made in photovoltaic material and processing options. At present there is growing interest in the commercial potential of cadmium telluride (CdTe) and copper indium diselenide (CIS) photovoltaic modules. As the commercial potential of these technologies becomes more apparent, interest in the environmental, health and safety issues associated with their production, use and disposal has also increased because of the continuing regulatory focus on cadmium and selenium. In future, recycling of spent or broken CdTe and CIS modules and manufacturing wastes may be needed for environmental, economic or political reasons. To assist industry to identify recycling options early in the commercialization process, a Workshop was convened. At this Workshop, representatives from the photovoltaic, electric utility, and nonferrous metals industries met to explore technical and institutional options for the recycling of spent CdTe and CIS modules and manufacturing wastes. This report summarizes the results of the Workshop. This report includes: (1) A discussion of the Resource Conservation and Recovery Act regulations and their potential implications to the photovoltaic industry; (2) an assessment of the needs of the photovoltaic industry from the perspective of module manufacturers and consumers; (3) an overview of recycling technologies now employed by other industries for similar types of materials; and, (4) a list of recommendation.

  10. Synthesis of Germanium-Gallium-Tellurium (Ge-Ga-Te) ceramics by ball-milling and sintering Mathieu Hubert, Elena Petracovschi, Xiang-Hua Zhang and Laurent Calvez*

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Synthesis of Germanium-Gallium-Tellurium (Ge-Ga-Te) ceramics by ball-milling and sintering Mathieu, France *laurent.calvez@univ-rennes1.fr Tel: (33) 2 23 23 67 13 Fax: (33) 2 23 23 56 11 Abstract, the semiconductor behavior of CdTe is exploited for the production of solar panels [1, 2], the rapid and reversible

  11. The reaction of carbon tetrachloride with gallium arsenide ,,001... L. Li., S, Gan, B.-K. Han, H. Qi, and R. F. Hicksa)

    E-Print Network [OSTI]

    Li, Lian

    The reaction of carbon tetrachloride with gallium arsenide ,,001... L. Li., S, Gan, B.-K. Han, H, California 90095 Received 26 June 1997; accepted for publication 30 December 1997 Carbon tetrachloride of steps during the vapor-phase epitaxial growth of III­V compound semiconductors.3,4 Carbon tetrachloride

  12. Formation of copper-indium-selenide and/or copper-indium-gallium-selenide films from indium selenide and copper selenide precursors

    DOE Patents [OSTI]

    Curtis, Calvin J. (Lakewood, CO); Miedaner, Alexander (Boulder, CO); Van Hest, Maikel (Lakewood, CO); Ginley, David S. (Evergreen, CO); Nekuda, Jennifer A. (Lakewood, CO)

    2011-11-15T23:59:59.000Z

    Liquid-based indium selenide and copper selenide precursors, including copper-organoselenides, particulate copper selenide suspensions, copper selenide ethylene diamine in liquid solvent, nanoparticulate indium selenide suspensions, and indium selenide ethylene diamine coordination compounds in solvent, are used to form crystalline copper-indium-selenide, and/or copper indium gallium selenide films (66) on substrates (52).

  13. Atomic layer structure of manganese atoms on wurtzite gallium nitride Abhijit Chinchore, Kangkang Wang, Wenzhi Lin, Jeongihm Pak, and Arthur R. Smitha

    E-Print Network [OSTI]

    Atomic layer structure of manganese atoms on wurtzite gallium nitride ,,0001Ż... Abhijit Chinchore on wurtzite GaN 0001Ż . The surface is monitored using reflection high energy electron diffraction, which to grow with an abrupt interface and well- defined epitaxial orientation on top of wurtzite w -GaN. Re

  14. Measurement of the solar neutrino capture rate with gallium metal, part III

    SciTech Connect (OSTI)

    Elliott, Steven Ray [Los Alamos National Laboratory

    2008-01-01T23:59:59.000Z

    The Russian-American experiment SAGE began to measure the solar neutrino capture rate with a target of gallium metal in December 1989. Measurements have continued with only a few brief interruptions since that time. In this article we present the experimental improvements in SAGE since its last published data summary in December 2001. Assuming the solar neutrino production rate was constant during the period of data collection, combined analysis of 168 extractions through December 2007 gives a capture rate of solar neutrinos with energy more than 233 keY of 65.4{sup +3.1}{sub 3.0} (stat) {sup +2.6}{sub -2.8} (syst) SNU. The weighted average of the results of all three Ga solar neUlrino experiments, SAGE, Gallex, and GNO, is now 66.1 {+-} 3.1 SNU, where statistical and systematic uncertainties have been combined in quadrature. During the recent period of data collection a new test of SAGE was made with a reactor-produced {sup 37}Ar neutrino source. The ratio of observed to calculated rates in this experiment, combined with the measured rates in the three prior {sup 51}Cr neutrino-source experiments with Ga, is 0.88 {+-} 0.05. A probable explanation for this low result is that the cross section for neutrino capture by the two lowest-lying excited states in {sup 71}Ge has been overestimated. If we assume these cross sections are zero, then the standard solar model including neutrino oscillations predicts a total capture rate in Ga in the range of 63--67 SNU with an uncertainly of about 5%, in good agreement with experiment. We derive the current value of the pp neutrino flux produced in the Sun to be {phi}{sup {circle_dot}}{sub pp} = (6.1 {+-} 0.8) x 10{sup 10}/(cm{sup 2} s), which agrees well with the flux predicted by the standard solar model. Finally, we make several tests and show that the data are consistent with the assumption that the solar neutrino production rate is constant in time.

  15. Effect of Sulfate on Selenium Uptake And Chemical Speciation in Convolvulus Arvensis L

    SciTech Connect (OSTI)

    Cruz-Jimenez, G.; Peralta-Video, J.R.; Rosa, G.de la; Meitzner, G.; Parson, J.G.; Gardea-Torresdey, J.L.

    2007-08-08T23:59:59.000Z

    Hydroponic experiments were performed to study several aspects of Se uptake by C. arvensis plants. Ten day old seedlings were exposed for eight days to different combinations of selenate (SeO{sub 4}{sup 2-}), sulfate (SO{sub 4}{sup 2-}), and selenite (SeO{sub 3}{sup 2-}). The results showed that in C. arvensis, SO{sub 4}{sup 2-} had a negative effect (P < 0.05) on SeO{sub 4}{sup 2-} uptake. However, a positive interaction produced a significant increase in SO{sub 4}{sup 2-} uptake when SeO{sub 4}{sup 2-} was at high concentration in the media. X-ray absorption spectroscopy studies showed that C. arvensis plants converted more than 70% of the supplied SeO{sub 3}{sup 2-} into organoselenium compounds. However, only approximately 50% of the supplied SeO{sub 4}{sup 2-} was converted into organoselenium species while the residual 50% remained in the inorganic form. Analysis using LC-XANES fittings confirmed that the S metabolic pathway was affected by the presence of Se. The main Se compounds that resembled those Se species identified in C. arvensis were Se-cystine, Se-cysteine, SeO{sub 3}{sup 2-}, and SeO{sub 4}{sup 2-}, whereas for S the main compounds were cysteine, cystine, oxidized glutathione, reduced glutathione, and SO{sub 4}{sup 2-}. The results of these studies indicated that C. arvensis could be considered as a possible option for the restoration of soil moderately contaminated with selenium even in the presence of sulfate.

  16. Digital radiography using amorphous selenium: Photoconductively activated switch (PAS) readout system

    SciTech Connect (OSTI)

    Reznik, Nikita; Komljenovic, Philip T.; Germann, Stephen; Rowlands, John A. [Imaging Research, Sunnybrook Health Sciences Centre, Department of Medical Biophysics, University of Toronto, 2075 Bayview Avenue, Toronto, Ontario, M4N 3M5 (Canada)

    2008-03-15T23:59:59.000Z

    A new amorphous selenium (a-Se) digital radiography detector is introduced. The proposed detector generates a charge image in the a-Se layer in a conventional manner, which is stored on electrode pixels at the surface of the a-Se layer. A novel method, called photoconductively activated switch (PAS), is used to read out the latent x-ray charge image. The PAS readout method uses lateral photoconduction at the a-Se surface which is a revolutionary modification of the bulk photoinduced discharge (PID) methods. The PAS method addresses and eliminates the fundamental weaknesses of the PID methods--long readout times and high readout noise--while maintaining the structural simplicity and high resolution for which PID optical readout systems are noted. The photoconduction properties of the a-Se surface were investigated and the geometrical design for the electrode pixels for a PAS radiography system was determined. This design was implemented in a single pixel PAS evaluation system. The results show that the PAS x-ray induced output charge signal was reproducible and depended linearly on the x-ray exposure in the diagnostic exposure range. Furthermore, the readout was reasonably rapid (10 ms for pixel discharge). The proposed detector allows readout of half a pixel row at a time (odd pixels followed by even pixels), thus permitting the readout of a complete image in 30 s for a 40 cmx40 cm detector with the potential of reducing that time by using greater readout light intensity. This demonstrates that a-Se based x-ray detectors using photoconductively activated switches could form a basis for a practical integrated digital radiography system.

  17. Methods of making copper selenium precursor compositions with a targeted copper selenide content and precursor compositions and thin films resulting therefrom

    DOE Patents [OSTI]

    Curtis, Calvin J. (Lakewood, CO); Miedaner, Alexander (Boulder, CO); van Hest, Marinus Franciscus Antonius Maria (Lakewood, CO); Ginley, David S. (Evergreen, CO); Leisch, Jennifer (Denver, CO); Taylor, Matthew (West Simsbury, CT); Stanbery, Billy J. (Austin, TX)

    2011-09-20T23:59:59.000Z

    Precursor compositions containing copper and selenium suitable for deposition on a substrate to form thin films suitable for semi-conductor applications. Methods of forming the precursor compositions using primary amine solvents and methods of forming the thin films wherein the selection of temperature and duration of heating controls the formation of a targeted species of copper selenide.

  18. Changes in Selenium, Copper, Cadmium, and Zinc Concentrations in Mullet (Mugil cephalus) from the Southern Basin of Lake Macquarie, Australia, in

    E-Print Network [OSTI]

    Canberra, University of

    attributed to power gener- ation activities and the production of selenium-contaminated fly ash. Two coal not been established but are believed to be partly from the activities of the coal-fired power station the Southern Basin of Lake Macquarie, Australia, in Response to Alteration of Coal-Fired Power Station Fly Ash

  19. Estimation of Loads of Mercury, Selenium, PCBs, PAHs, PBDEs, Dioxins, and1 Organochlorine Pesticides from the Sacramento-San Joaquin River Delta to San2

    E-Print Network [OSTI]

    1 Estimation of Loads of Mercury, Selenium, PCBs, PAHs, PBDEs, Dioxins, and1 Organochlorine concentrations from the Sacramento- San Joaquin River watershed were9 determined in water samples during flood 1.6 and 6.1%, respectively. Also monitored were PAHs, PBDEs (two years of19 data), and dioxins

  20. High-performance amorphous gallium indium zinc oxide thin-film transistors through N{sub 2}O plasma passivation

    SciTech Connect (OSTI)

    Park, Jaechul; Kim, Sangwook; Kim, Changjung; Kim, Sunil; Song, Ihun; Yin, Huaxiang; Kim, Kyoung-Kok; Lee, Sunghoon; Hong, Kiha; Park, Youngsoo [Semiconductor Device Laboratory, Samsung Advanced Institute of Technology, Yongin-Si, Gyeonggi-Do 449-712 (Korea, Republic of); Lee, Jaecheol; Jung, Jaekwan; Lee, Eunha [Analytical Engineering Center, Samsung Advanced Institute of Technology, Yongin-Si, Gyeonggi-Do 449-712 (Korea, Republic of); Kwon, Kee-Won [Department of Semiconductor Systems Engineering, Sungkyunkwan University, Suwon-Si, Gyeonggi-Do 440-746 (Korea, Republic of)

    2008-08-04T23:59:59.000Z

    Amorphous-gallium-indium-zinc-oxide (a-GIZO) thin filmtransistors (TFTs) are fabricated without annealing, using processes and equipment for conventional a-Si:H TFTs. It has been very difficult to obtain sound TFT characteristics, because the a-GIZO active layer becomes conductive after dry etching the Mo source/drain electrode and depositing the a-SiO{sub 2} passivation layer. To prevent such damages, N{sub 2}O plasma is applied to the back surface of the a-GIZO channel layer before a-SiO{sub 2} deposition. N{sub 2}O plasma-treated a-GIZO TFTs exhibit excellent electrical properties: a field effect mobility of 37 cm{sup 2}/V s, a threshold voltage of 0.1 V, a subthreshold swing of 0.25 V/decade, and an I{sub on/off} ratio of 7.

  1. Compact, Interactive Electric Vehicle Charger: Gallium-Nitride Switch Technology for Bi-directional Battery-to-Grid Charger Applications

    SciTech Connect (OSTI)

    None

    2010-10-01T23:59:59.000Z

    ADEPT Project: HRL Laboratories is using gallium nitride (GaN) semiconductors to create battery chargers for electric vehicles (EVs) that are more compact and efficient than traditional EV chargers. Reducing the size and weight of the battery charger is important because it would help improve the overall performance of the EV. GaN semiconductors process electricity faster than the silicon semiconductors used in most conventional EV battery chargers. These high-speed semiconductors can be paired with lighter-weight electrical circuit components, which helps decrease the overall weight of the EV battery charger. HRL Laboratories is combining the performance advantages of GaN semiconductors with an innovative, interactive battery-to-grid energy distribution design. This design would support 2-way power flow, enabling EV battery chargers to not only draw energy from the power grid, but also store and feed energy back into it.

  2. An experiment to test the viability of a gallium-arsenide cathode in a SRF electron gun

    SciTech Connect (OSTI)

    Kewisch,J.; Ben-Zvi, I.; Rao, T.; Burrill, A.; Pate, D.; Wu, Q.; Todd, R.; Wang, E.; Bluem, H.; Holmes, D.; Schultheiss, T.

    2009-05-04T23:59:59.000Z

    Strained gallium arsenide cathodes are used in electron guns for the production of polarized electrons. In order to have a sufficient quantum efficiency lifetime of the cathode the vacuum in the gun must be 10{sup -11} Torr or better, so that the cathode is not destroyed by ion back bombardment or through contamination with residual gases. All successful polarized guns are DC guns, because such vacuum levels can not be obtained in normal conducting RF guns. A superconductive RF gun may provide a sufficient vacuum level due to cryo-pumping of the cavity walls. We report on the progress of our experiment to test such a gun with normal GaAs-Cs crystals.

  3. Low-temperature growth of gallium nitride films by inductively coupled-plasma-enhanced reactive magnetron sputtering

    SciTech Connect (OSTI)

    Ni, Chih-Jui; Chau-Nan Hong, Franklin, E-mail: hong@mail.ncku.edu.tw [Department of Chemical Engineering, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China)

    2014-05-15T23:59:59.000Z

    Gallium nitride (GaN) films were grown on sapphire substrate by reactive magnetron sputtering. Inductively coupled-plasma (ICP) source was installed between the substrate holder and the sputtering target to increase the plasma density and the degree of ionization of nitrogen gas. Liquid Ga and Ar/N{sub 2} were used as the sputtering target and sputtering gases, respectively. X-ray diffraction measurements confirmed that the authors could grow high quality GaN crystallites at 500?°C. However, the crystalline GaN (0002) peak remained even by lowering the growth temperature down to 300?°C. The N:Ga ratio of the film grown at 500?°C was almost 1:1, and the nitrogen composition became higher toward the 1:1 N:Ga ratio with increasing the growth temperature. The high degree of ionization induced by ICP source was essential to the growth of high crystalline quality GaN films.

  4. integrative www.unil.ch/cig

    E-Print Network [OSTI]

    Kaessmann, Henrik

    on plant growth and development 12 Paul Franken Genetics and energetics of sleep homeostasis and circadian the acquisition of new technologies or the development of new research and educational activities or services

  5. Gas source molecular beam epitaxy of scandium nitride on silicon carbide and gallium nitride surfaces

    SciTech Connect (OSTI)

    King, Sean W., E-mail: sean.king@intel.com; Davis, Robert F. [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Nemanich, Robert J. [Department of Physics, North Carolina State University, Raleigh, North Carolina 27695 (United States)

    2014-11-01T23:59:59.000Z

    Scandium nitride (ScN) is a group IIIB transition metal nitride semiconductor with numerous potential applications in electronic and optoelectronic devices due to close lattice matching with gallium nitride (GaN). However, prior investigations of ScN have focused primarily on heteroepitaxial growth on substrates with a high lattice mismatch of 7%–20%. In this study, the authors have investigated ammonia (NH{sub 3}) gas source molecular beam epitaxy (NH{sub 3}-GSMBE) of ScN on more closely lattice matched silicon carbide (SiC) and GaN surfaces (<3% mismatch). Based on a thermodynamic analysis of the ScN phase stability window, NH{sub 3}-GSMBE conditions of 10{sup ?5}–10{sup ?4} Torr NH{sub 3} and 800–1050?°C where selected for initial investigation. In-situ x-ray photoelectron spectroscopy (XPS) and ex-situ Rutherford backscattering measurements showed all ScN films grown using these conditions were stoichiometric. For ScN growth on 3C-SiC (111)-(?3?×??3)R30° carbon rich surfaces, the observed attenuation of the XPS Si 2p and C 1s substrate core levels with increasing ScN thickness indicated growth initiated in a layer-by-layer fashion. This was consistent with scanning electron microscopy (SEM) images of 100–200?nm thick films that revealed featureless surfaces. In contrast, ScN films grown on 3C-SiC (111)-(3?×?3) and 3C-SiC (100)-(3?×?2) silicon rich surfaces were found to exhibit extremely rough surfaces in SEM. ScN films grown on both 3C-SiC (111)-(?3?×??3)R30° and 2H-GaN (0001)-(1?×?1) epilayer surfaces exhibited hexagonal (1?×?1) low energy electron diffraction patterns indicative of (111) oriented ScN. X-ray diffraction ?-2? rocking curve scans for these same films showed a large full width half maximum of 0.29° (1047?arc sec) consistent with transmission electron microscopy images that revealed the films to be poly-crystalline with columnar grains oriented at ?15° to the [0001] direction of the 6H-SiC (0001) substrate. In-situ reflection electron energy loss spectroscopy measurements determined the band-gap for the NH{sub 3}-GSMBE ScN films to be 1.5?±?0.3 eV, and thermal probe measurements indicated all ScN films to be n-type. The four point probe sheet resistance of the ScN films was observed to increase with decreasing growth temperature and decreased with unintentional oxygen incorporation. Hg probe capacitance–voltage measurements indicated N{sub D}-N{sub A} decreased with decreasing growth temperature from 10{sup 19} to 10{sup 20}/cm{sup 3} for the lowest resistivity films to ?5?×?10{sup 16}/cm{sup 3} for the highest resistivity films. In-situ ultraviolet photoelectron spectroscopy measurements additionally showed the valence band maximum moving from 1.4 to 0.8 eV below the Fermi level with decreasing growth temperature consistent with the increased resistivity and reduction in carrier concentration. These results suggest that additional reductions in ScN carrier concentrations can be achieved via continued optimization of ScN growth conditions and selection of substrate orientation and surface termination.

  6. Selenium fractionation and cycling in the intertidal zone of the Carquinez Strait. Quarterly progress report, October 1995--December 1995

    SciTech Connect (OSTI)

    Zawislanski, P.T.; McGrath, A.E.; Benson, S.M. [and others

    1996-01-01T23:59:59.000Z

    This quarterly report describes the research on selenium (Se) cycling in the marshes and mudflats of the Carquinez Strait between October 1, 1995 and December 31, 1995. Chapter 2 contains descriptions of field activities and laboratory work related to chemical characterization of sediments and soils. Eh and pH data are presented. Chapter 3 contains a summary of work in progress on the extraction of various Se species from sediment/soil samples, and efforts in measuring suspended sediment Se. Chapter 4 describes advances made in the analysis of parts-per-trillion level Se, using a lanthanum hydroxide co-precipitation method, and the determination of matrix effects. Chapter 5 is an update on stable Se isotope research and Se purification techniques. The reader is referred to the 1995 Annual Report for details on the project design, site selection, and methodology.

  7. Selenium fractionation and cycling in the intertidal zone of the Carquinez Strait. Quarterly progress report, January 1996--March 1996

    SciTech Connect (OSTI)

    Zawislanski, P.T.; Benson, S.M.; Brownfield, A.A. [and others

    1996-04-01T23:59:59.000Z

    This quarterly report describes research on selenium (Se) cycling in the marshes and mudflats of the Carquinez Strait between January 1, 1996 and March 31, 1996. Chapter 2 contains descriptions of results of extractions and analyses of sediment cores from the intertidal zone of the Martinez and Benicia field sites, including some x-ray spectroscopy data related to the characterization of the sediment Eh-pH regime. Chapter 3 contains a summary of work in progress on the extraction of various Se species from sediment/soil samples, and efforts in measuring suspended sediment Se. Chapter 4 is an update on stable Se isotope research and Se purification techniques. Chapter 5 describes the rationale, design, and preliminary results of a plant-Se study. Chapter 6 presents the design of a recently initiated sediment dynamics study. The leader is referred to the 1995 Annual Report for details on the project design, site selection, and methodology.

  8. Selenium fractionation and cycling in the intertidal zone of Carquinez Strait. Quarterly progress report, April 1996--June 1996

    SciTech Connect (OSTI)

    Zawislanski, P.T.; Benson, S.M.; Brownfield, A.A.; Chau, S. [and others

    1996-07-01T23:59:59.000Z

    This quarterly report describes research on selenium (Se) cycling in the marshes and mudflats of the Carquinez Strait between 4/1/96 and 6/30/96. Chapter 2 contains descriptions of results of extractions and analyses of sediment cores from the intertidal zone of the Martinez and Benicia field sites, including Se fractionation data from Martinez Regional Park. Chapter 3 contains a summary of work in progress on the extraction of various Se species from sediment/soil samples, and efforts in measuring suspended sediment Se. Chapter 4 is an update on stable Se isotope research and Se purification techniques. Chapter 5 describes the recent developments in low-level Se analytical methods. Chapter 6 presents preliminary sedimentation rate data from the Martinez field site. Exciting new developments in x-ray spectroscopy of clams are presented in Chapter 7. The reader is referred to the 1995 Annual Report for details on the project design, site selection, and methodology.

  9. Information technology and innovative drainage management practices for selenium load reduction from irrigated agriculture to provide stakeholder assurances and meet contaminant mass loading policy objectives

    SciTech Connect (OSTI)

    Quinn, N.W.T.

    2009-10-15T23:59:59.000Z

    Many perceive the implementation of environmental regulatory policy, especially concerning non-point source pollution from irrigated agriculture, as being less efficient in the United States than in many other countries. This is partly a result of the stakeholder involvement process but is also a reflection of the inability to make effective use of Environmental Decision Support Systems (EDSS) to facilitate technical information exchange with stakeholders and to provide a forum for innovative ideas for controlling non-point source pollutant loading. This paper describes one of the success stories where a standardized Environmental Protection Agency (EPA) methodology was modified to better suit regulation of a trace element in agricultural subsurface drainage and information technology was developed to help guide stakeholders, provide assurances to the public and encourage innovation while improving compliance with State water quality objectives. The geographic focus of the paper is the western San Joaquin Valley where, in 1985, evapoconcentration of selenium in agricultural subsurface drainage water, diverted into large ponds within a federal wildlife refuge, caused teratogenecity in waterfowl embryos and in other sensitive wildlife species. The fallout from this environmental disaster was a concerted attempt by State and Federal water agencies to regulate non-point source loads of the trace element selenium. The complexity of selenium hydrogeochemistry, the difficulty and expense of selenium concentration monitoring and political discord between agricultural and environmental interests created challenges to the regulation process. Innovative policy and institutional constructs, supported by environmental monitoring and the web-based data management and dissemination systems, provided essential decision support, created opportunities for adaptive management and ultimately contributed to project success. The paper provides a retrospective on the contentious planning process and offers suggestions as to how the technical and institutional issues could have been resolved faster through early adoption of some of the core principles of sound EDSS design.

  10. Selenium fractionation and cycling in the intertidal zone of the Carquinez Strait. Draft annual report, October 1, 1994--September 30, 1995

    SciTech Connect (OSTI)

    Zawislanski, P.T.; McGrath, A.E.; Benson, S.M.; Mountford, H.S. [and others

    1995-11-01T23:59:59.000Z

    Research aimed at gaining a better understanding of selenium cycling in marshes and mudflats of the Carquinez Strait is being performed by scientists from Lawrence Berkeley National Laboratory and collaborators from the University of California at Davis. This work was initiated in the Fall of 1994 and is scheduled to continue through the Fall of 1996. This report summarizes the results of the effort to date.

  11. CO{sub 2} laser-based dispersion interferometer utilizing orientation-patterned gallium arsenide for plasma density measurements

    SciTech Connect (OSTI)

    Bamford, D. J.; Cummings, E. A.; Panasenko, D. [Physical Sciences Inc., 6652 Owens Drive, Pleasanton, California 94588 (United States)] [Physical Sciences Inc., 6652 Owens Drive, Pleasanton, California 94588 (United States); Fenner, D. B.; Hensley, J. M. [Physical Sciences Inc., 20 New England Business Center, Andover, Massachusetts 01810 (United States)] [Physical Sciences Inc., 20 New England Business Center, Andover, Massachusetts 01810 (United States); Boivin, R. L.; Carlstrom, T. N.; Van Zeeland, M. A. [General Atomics, P.O. Box 85608, San Diego, California 92186 (United States)] [General Atomics, P.O. Box 85608, San Diego, California 92186 (United States)

    2013-09-15T23:59:59.000Z

    A dispersion interferometer based on the second-harmonic generation of a carbon dioxide laser in orientation-patterned gallium arsenide has been developed for measuring electron density in plasmas. The interferometer includes two nonlinear optical crystals placed on opposite sides of the plasma. This instrument has been used to measure electron line densities in a pulsed radio-frequency generated argon plasma. A simple phase-extraction technique based on combining measurements from two successive pulses of the plasma has been used. The noise-equivalent line density was measured to be 1.7 × 10{sup 17} m{sup ?2} in a detection bandwidth of 950 kHz. One of the orientation-patterned crystals produced 13 mW of peak power at the second-harmonic wavelength from a carbon dioxide laser with 13 W of peak power. Two crystals arranged sequentially produced 58 mW of peak power at the second-harmonic wavelength from a carbon dioxide laser with 37 W of peak power.

  12. Photon self-induced spin-to-orbital conversion in a terbium-gallium-garnet crystal at high laser power

    SciTech Connect (OSTI)

    Mosca, S.; De Rosa, R.; Milano, L. [Dipartimento di Scienze Fisiche, Universita di Napoli 'Federico II', Complesso Universitario di Monte S. Angelo, 80126 Napoli (Italy); INFN Sezione di Napoli, Complesso Universitario di Monte S. Angelo, 80126 Napoli (Italy); Canuel, B.; Genin, E. [EGO, European Gravitational Observatory, Via E. Amaldi, 56021 S. Stefano a Macerata, Cascina (Italy); Karimi, E. [Dipartimento di Scienze Fisiche, Universita di Napoli 'Federico II', Complesso Universitario di Monte S. Angelo, 80126 Napoli (Italy); Piccirillo, B.; Santamato, E. [Dipartimento di Scienze Fisiche, Universita di Napoli 'Federico II', Complesso Universitario di Monte S. Angelo, 80126 Napoli (Italy); CNISM-Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, Napoli (Italy); Marrucci, L. [Dipartimento di Scienze Fisiche, Universita di Napoli 'Federico II', Complesso Universitario di Monte S. Angelo, 80126 Napoli (Italy); CNR-INFM Coherentia, Complesso Universitario di Monte S. Angelo, 80126 Napoli (Italy)

    2010-10-15T23:59:59.000Z

    In this paper, we present experimental evidence of a third-order nonlinear optical process, self-induced spin-to-orbital conversion (SISTOC) of the photon angular momentum. This effect is the physical mechanism at the origin of the depolarization of very intense laser beams propagating in isotropic materials. The SISTOC process, like self-focusing, is triggered by laser heating leading to a radial temperature gradient in the medium. In this work we tested the occurrence of SISTOC in a terbium-gallium-garnet rod for an impinging laser power of about 100 W. To study the SISTOC process we used different techniques: polarization analysis, interferometry, and tomography of the photon orbital angular momentum. Our results confirm, in particular, that the apparent depolarization of the beam is due to the occurrence of maximal entanglement between the spin and orbital angular momentum of the photons undergoing the SISTOC process. This explanation of the true nature of the depolarization mechanism could be of some help in finding novel methods to reduce or to compensate for this usually unwanted depolarization effect in all cases where very high laser power and good beam quality are required.

  13. Saddle-like deformation in a dielectric elastomer actuator embedded with liquid-phase gallium-indium electrodes

    SciTech Connect (OSTI)

    Wissman, J., E-mail: jwissman@andrew.cmu.edu [Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Finkenauer, L. [Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Deseri, L. [DICAM, Department of Mechanical, Civil and Environmental Engineering, University of Trento, via Mesiano 77 38123 Trento (Italy); TMHRI-Department of Nanomedicine, The Methodist Hospital Research Institute, 6565 Fannin St., MS B-490 Houston, Texas 77030 (United States); Mechanics, Materials and Computing Center, CEE and ME-CIT, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Majidi, C. [Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Robotics Institute and Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)

    2014-10-14T23:59:59.000Z

    We introduce a dielectric elastomer actuator (DEA) composed of liquid-phase Gallium-Indium (GaIn) alloy electrodes embedded between layers of poly(dimethylsiloxane) (PDMS) and examine its mechanics using a specialized elastic shell theory. Residual stresses in the dielectric and sealing layers of PDMS cause the DEA to deform into a saddle-like geometry (Gaussian curvature K<0). Applying voltage ? to the liquid metal electrodes induces electrostatic pressure (Maxwell stress) on the dielectric and relieves some of the residual stress. This reduces the longitudinal bending curvature and corresponding angle of deflection ?. Treating the elastomer as an incompressible, isotropic, NeoHookean solid, we develop a theory based on the principle of minimum potential energy to predict the principal curvatures as a function of ?. Based on this theory, we predict a dependency of ? on ? that is in strong agreement with experimental measurements performed on a GaIn-PDMS composite. By accurately modeling electromechanical coupling in a soft-matter DEA, this theory can inform improvements in design and fabrication.

  14. A first-principles study of the electronic structure of Iron-Selenium; Implications for electron-phonon superconductivity

    E-Print Network [OSTI]

    Koufos, Alexander P; Mehl, Michael J

    2013-01-01T23:59:59.000Z

    We have performed density functional theory (DFT) calculations using the linearized augmented plane wave method (LAPW) with the local density approximation (LDA) functional to study the electronic structure of the iron-based superconductor Iron-Selenium (FeSe). In our study, we have performed a comprehensive set of calculations involving structural, atomic, and spin configurations. All calculations were executed using the tetragonal lead-oxide or P4/nmm structure, with various volumes, c/a ratios and internal parameters. Furthermore, we investigated the spin polarization using the LDA functional to assess ferromagnetism in this material. The paramagnetic LDA calculations find the equilibrium configuration of FeSe in the P4/nmm structure to have a volume of 472.5au$^3$ with a c/a ratio of 1.50 and internal parameter of 0.255, with the ferromagnetic having comparable results to the paramagnetic case. In addition, we calculated total energies for FeSe using a pseudopotential method, and found comparable results ...

  15. Hydrological and geochemical investigations of selenium behavior at Kesterson Reservoir. Progress report, October 1, 1994--September 30, 1996

    SciTech Connect (OSTI)

    Zawislanski, P.; Tokunaga, T.; Benson, S.M. [and others

    1997-10-01T23:59:59.000Z

    This report describes research relevant to selenium (Se) speciation, fractionation, physical redistribution, reduction and oxidation, and spatial distribution as related to Kesterson Reservoir. The work was carried out by scientists and engineers from the Earth Sciences Division of the Lawrence Berkeley Laboratory over a two year period from October 1994 to September 1996. Much of the focus of this research was on long-term, Reservoir-wide changes in Se concentrations and distribution; estimation and prediction of the physical extent ephemeral pools; and the quantification and prediction of Se levels in ephemeral pools waters and underlying sediments. Chapter 2 contains descriptions of field monitoring of soil processes. In Section 2.1, elevated Se concentrations observed in groundwater in the northern part of Pond 9 are investigated. The past removal of the original surface soil in the northern Pond 9 area resulted in the enhancement of Se transport into the shallow groundwater in this area. Removal of the most organic-rich surface soil horizon left the remaining profile with a lower capacity to generate and sustain reducing conditions needed to immobilize Se. Furthermore, removal of the lower permeability surface soil left the remaining profile more hydraulically conductive since sands are encountered at fairly shallow depths. These conditions result in Se remaining oxidized down to the 2.00 m depth throughout the year.

  16. Low-temperature synthesis of gallium nitride thin films using electron cyclotron resonance plasma assisted pulsed laser deposition from a GaAs target

    SciTech Connect (OSTI)

    Sun, J.; Wu, A.M.; Xu, N.; Ying, Z.F.; Shen, X.K.; Dong, Z.B.; Wu, J.D.; Shi, L.Q. [State Key Laboratory for Advanced Photonic Materials and Devices, Department of Optical Science and Engineering, Fudan University, Shanghai 200433 (China); Institute of Modern Physics, Fudan University, Shanghai 200433 (China)

    2005-11-15T23:59:59.000Z

    Using reactive pulsed laser deposition assisted by electron cyclotron resonance (ECR) plasma, we have synthesized GaN thin films from a polycrystalline GaAs target at low temperatures. This was achieved by ablating the GaAs target in the reactive environment of a nitrogen plasma generated from ECR microwave discharge in pure nitrogen gas and depositing the films with concurrent bombardment by the low-energy nitrogen plasma stream. High-energy ion backscattering spectroscopy analysis shows that the synthesized films are gallium rich. Characterizations by x-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy confirm the presence of GaN bonds in the films. The recorded absorption spectrum also reveals GaN stretching mode characteristic of the hexagonal GaN phase. The synthesized GaN films are transparent in the visible region and have a band gap of 3.38 eV. Optical emission from the plume during film deposition reveals that the plume created by pulsed laser ablation of the GaAs target consists mainly of monoatomic atoms and ions of gallium and arsenic. Mechanisms responsible for the formation of GaN molecules and the growth of GaN films are also discussed.

  17. Rare-earth metal gallium silicides via the gallium self-flux method. Synthesis, crystal structures, and magnetic properties of RE(Ga1–xSix)? (RE=Y, La–Nd, Sm, Gd–Yb, Lu)

    SciTech Connect (OSTI)

    Darone, Gregory M.; Hmiel, Benjamin; Zhang, Jiliang [Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716 (United States); Saha, Shanta; Kirshenbaum, Kevin; Greene, Richard; Paglione, Johnpierre [Department of Physics, University of Maryland, College Park, Maryland 20742 (United States); Bobev, Svilen, E-mail: bobev@udel.edu [Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716 (United States)

    2013-05-01T23:59:59.000Z

    Fifteen ternary rare-earth metal gallium silicides have been synthesized using molten Ga as a molten flux. They have been structurally characterized by single-crystal and powder X-ray diffraction to form with three different structures—the early to mid-late rare-earth metals RE=La–Nd, Sm, Gd–Ho, Yb and Y form compounds with empirical formulae RE(GaxSi1–x)? (0.38?x?0.63), which crystallize with the tetragonal ?-ThSi? structure type (space group I4?/amd, No. 141; Pearson symbol tI12). The compounds of the late rare-earth crystallize with the orthorhombic ?-GdSi? structure type (space group Imma, No. 74; Pearson symbol oI12), with refined empirical formula REGaxSi2–x–y (RE=Ho, Er, Tm; 0.33?x?0.40, 0.10?y?0.18). LuGa?.?????Si?.????? crystallizes with the orthorhombic YbMn?.??Si?.?? structure type (space group Cmcm, No. 63; Pearson symbol oC24). Structural trends are reviewed and analyzed; the magnetic susceptibilities of the grown single-crystals are presented. - Graphical abstract: This article details the exploration of the RE–Ga–Si ternary system with the aim to systematically investigate the structural “boundaries” between the ?-ThSi? and ?-GdSi?-type structures, and studies of the magnetic properties of the newly synthesized single-crystalline materials. Highlights: • Light rare-earth gallium silicides crystallize in ?-ThSi? structure type. • Heavy rare-earth gallium silicides crystallize in ?-GdSi? structure type. • LuGaSi crystallizes in a defect variant of the YbMn?.??Si?.?? structure type.

  18. Alumina nanoparticle/polymer nanocomposite dielectric for flexible amorphous indium-gallium-zinc oxide thin film transistors on plastic substrate with superior stability

    SciTech Connect (OSTI)

    Lai, Hsin-Cheng [Department of Electrical Engineering, National Chung Hsing University, Taichung 40227, Taiwan (China); Pei, Zingway, E-mail: zingway@dragon.nchu.edu.tw [Department of Electrical Engineering, National Chung Hsing University, Taichung 40227, Taiwan (China); Graduate Institute of Optoelectronic Engineering, National Chung Hsing University, Taichung 40227, Taiwan (China); Center of Nanoscience and Nanotechnology, National Chung Hsing University, Taichung 40227, Taiwan (China); Jian, Jyun-Ruri; Tzeng, Bo-Jie [Graduate Institute of Optoelectronic Engineering, National Chung Hsing University, Taichung 40227, Taiwan (China)

    2014-07-21T23:59:59.000Z

    In this study, the Al{sub 2}O{sub 3} nanoparticles were incorporated into polymer as a nono-composite dielectric for used in a flexible amorphous Indium-Gallium-Zinc Oxide (a-IGZO) thin-film transistor (TFT) on a polyethylene naphthalate substrate by solution process. The process temperature was well below 100?°C. The a-IGZO TFT exhibit a mobility of 5.13?cm{sup 2}/V s on the flexible substrate. After bending at a radius of 4?mm (strain?=?1.56%) for more than 100 times, the performance of this a-IGZO TFT was nearly unchanged. In addition, the electrical characteristics are less altered after positive gate bias stress at 10?V for 1500?s. Thus, this technology is suitable for use in flexible displays.

  19. John Tyler McGoffin 830 Mathews St. jtmcgoffin@gmail.com Fort Collins, CO 80521

    E-Print Network [OSTI]

    Sites, James R.

    and Characterization of Thin Film photovoltaic devices including Current Density Voltage (JV), Quantum Efficiency (QETe) and Copper Indium Gallium diSelenide (CIGS) thin film photovoltaic devices using Close Space Sublimation (CSS approachable and easy to talk to #12;Employment: Founder January 2014 - Present Photovoltaic Imaging Systems

  20. 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1wileyonlinelibrary.com COMMUNICATION

    E-Print Network [OSTI]

    .88% Efficient Tin Sulfide Solar Cells using Congruent Thermal Evaporation Vera Steinmann,* R. Jaramillo, Katy reported PCE for TE SnS solar cells is 1.6%, with a small device area of 0.01 cm2.[10] The cur- rent Sn-per-year (GW/yr) levels,[1] while PV cells based on copper (indium, gallium) (diselenide, disulfide) (CIGS

  1. Effects of Series Resistance and Inductance on Solar Cell Admittance Measurements(a)

    E-Print Network [OSTI]

    Scofield, John H.

    on a variety of 0.43 cm2 area, copper indium gallium diselenide (CIGS) polycrystalline thin film solar cellsEffects of Series Resistance and Inductance on Solar Cell Admittance Measurements(a) John H Energy Materials and Solar Cells on April 17, 1994) Admittance measurements have been performed

  2. When you think of the film industry, what comes to mind? Entertainment. In this issue you will discover how films not only bring us the latest adventures but also are being sculptured at

    E-Print Network [OSTI]

    Demirel, Melik C.

    rooftop market. Solyndra uses a copper-indium-gallium-diselenide (CIGS) absorber layer in its solar cell to create revolutionary optics, semiconductors, medical devices, and solar cells. Spring 2009 In This Issue information, visit: www.jbg3.net Alumni Spotlight Phil Kraus (B.S. '93) is the director of technology at solar-cell

  3. COMMUNICATION www.MaterialsViews.com

    E-Print Network [OSTI]

    A, Weinheim (1 of 7) 1301916wileyonlinelibrary.com Improved Cu2O-Based Solar Cells Using Atomic Layer cell materials including copper indium gallium selenide (CIGS).[16] In the past, chemical treatments in enhancements of solar cell performance.[5,7,18] However, even if the surface treatments remove the CuO layer

  4. Sputtered Molybdenum Bilayer Back Contact for Copper Indium Diselenide-Based Polycrystalline Thin-Film Solar Cells

    E-Print Network [OSTI]

    Scofield, John H.

    of the CIS or CIGS solar cell structure (not to scale). In these investigations, however, the metal layers-Film Solar Cells John H. Scofield1, A. Duda, and D. Albin National Renewable Energy Laboratory, 1617 Cole-of-the-art polycrystalline copper indium gallium diselenide solar cells with good results. Thin Solid Films, 260 (1), pp. 26

  5. Progress Toward a Stabilization and Preconditioning Protocol for Polycrystalline Thin-Film Photovoltaic Modules

    SciTech Connect (OSTI)

    del Cueto, J. A.; Deline, C. A.; Rummel, S. R.; Anderberg, A.

    2010-08-01T23:59:59.000Z

    Cadmium telluride (CdTe) and copper indium gallium diselenide (CIGS) thin-film photovoltaic (PV) modules can exhibit substantial variation in measured performance depending on prior exposure history. This study examines the metastable performance changes in these PV modules with the goal of establishing standard preconditioning or stabilization exposure procedures to mitigate measured variations prior to current-voltage (IV) measurements.

  6. 2010 Minerals Yearbook U.S. Department of the Interior

    E-Print Network [OSTI]

    in 2010. A number of smaller companies produced specialty indium alloys and other indium products (t) of indium. The company has owned the property since 2005 (Lithic Resources Ltd., 2010). Indium and sputtering takes place. Indium can also be recovered from copper-indium-gallium- diselenide (CIGS) solar

  7. Gallium interactions with Zircaloy

    E-Print Network [OSTI]

    West, Michael Keith

    1998-01-01T23:59:59.000Z

    -nitride insulated cylinder wrapped with a tantalum oven wire and provides for evaporation of solid source materials. For an appropriate combination of gas pressure, filament current, and anode voltage, a plasma is formed in the hollow cathode region of the source... of the goniometer motor above 100 'C. In addition, braided copper straps were wrapped around the goniometer motors and connected to the cold plates in the target chamber. Zirc-4 Target Heater Wire Current = 2. 5 A To Current Integrator Inner Cup Bias = -200...

  8. Gallium interactions with Zircaloy 

    E-Print Network [OSTI]

    West, Michael Keith

    1998-01-01T23:59:59.000Z

    with Rutherford backscattering and SIMS techniques. Results indicate that the Zirc-4 is little affected up to a fluency of [] Ga ions/[]. After implantation of [] Ga ions/[], sub-grain features on the order of 2 gm were observed which may be due to intermetallic...

  9. Indium and gallium oxynitrides prepared in the presence of Zn{sup 2+} by ammonolysis of the oxide precursors obtained via the citrate route

    SciTech Connect (OSTI)

    Miyaake, Azumi; Masubuchi, Yuji; Takeda, Takashi [Graduate School of Engineering, Hokkaido University, N13W8, Kita-ku, Sapporo 060-8628 (Japan)] [Graduate School of Engineering, Hokkaido University, N13W8, Kita-ku, Sapporo 060-8628 (Japan); Kikkawa, Shinichi, E-mail: kikkawa@eng.hokudai.ac.jp [Graduate School of Engineering, Hokkaido University, N13W8, Kita-ku, Sapporo 060-8628 (Japan)] [Graduate School of Engineering, Hokkaido University, N13W8, Kita-ku, Sapporo 060-8628 (Japan)

    2010-04-15T23:59:59.000Z

    Ammonia nitridation of indium and gallium oxide precursors obtained through a soft solution route led to their oxynitrides [In{sub 0.97}{open_square}{sub 0.03}][N{sub 0.92}O{sub 0.08}] at 660 {sup o}C and [Ga{sub 0.89}{open_square}{sub 0.11}][N{sub 0.66}O{sub 0.34}] at 850 {sup o}C, respectively, where {open_square} refers to a In or Ga vacancy. Cation vacancies in their wurtzite-type lattice were eliminated in similar preparations with the co-presence of Zn{sup 2+} by forming complete solid solutions of (InN){sub 1-x}(ZnO){sub x} and (GaN){sub 1-y}(ZnO){sub y}. The optical absorption edge shape was found to be relatively steep at the solid solution limits of x {approx} 0.23 and y {approx} 0.33 compared to the case without zinc.

  10. Relationship between selenium body burdens and tissue concentrations in fish exposed to coal ash at the Tennessee Valley Authority Kingston spill site

    SciTech Connect (OSTI)

    Mathews, Teresa J [ORNL; Fortner, Allison M [ORNL; Jett, Robert T [ORNL; Peterson, Mark J [ORNL; Carriker, Neil [Tennessee Valley Authority (TVA); Morris, Jesse G [ORNL; Gable, Jennifer [Environmental Standards, Inc.

    2014-01-01T23:59:59.000Z

    In December 2008, 4.1 million m3 of coal ash were released into the Emory and Clinch Rivers by the Tennessee Valley Authority (TVA) Kingston Fossil Plant. Coal ash contains several contaminants, including the bioaccumulative metalloid selenium (Se). Because Se is predominantly accumulated in aquatic organisms through dietary, rather than aqueous exposure, tissue-based toxicity thresholds for Se are currently being considered. The proposed threshold concentrations range between 4-9 g/g Se (dry wt.) in whole body fish, with a proposed fillet threshold of 11.8 g/g. In the present study we examined the spatial and temporal trends in Se bioaccumulation and examined the relationship between the Se content in fillets and in whole bodies of fish collected around the Kingston spill site to determine whether Se bioaccumulation was a significant concern at the ash spill site. While Se concentrations in fish (whole bodies and fillets) were elevated at sampling locations affected by the Kingston ash spill relative to reference locations, concentrations do not appear to be above risk thresholds and have not been increasing over the five year period since the spill. Our results are not only relevant to guiding the human health and ecological risk assessments at the Kingston ash spill site, but because of current national discussions on appropriate guidelines for Se in fish as well for the disposal of coal combustion wastes, our results are also relevant to the general understanding of Se bioaccumulation in contaminated water bodies.

  11. Measurement of the solar neutrino capture rate with gallium metal. III. Results for the 2002-2007 data-taking period

    SciTech Connect (OSTI)

    Abdurashitov, J. N.; Gavrin, V. N.; Gorbachev, V. V.; Gurkina, P. P.; Ibragimova, T. V.; Kalikhov, A. V.; Khairnasov, N. G.; Knodel, T. V.; Mirmov, I. N.; Shikhin, A. A.; Veretenkin, E. P.; Yants, V. E.; Zatsepin, G. T.; Bowles, T. J.; Elliott, S. R.; Teasdale, W. A.; Nico, J. S.; Cleveland, B. T.; Wilkerson, J. F. [Institute for Nuclear Research, Russian Academy of Sciences, RU-117312 Moscow (Russian Federation); Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); National Institute of Standards and Technology, Stop 8461, Gaithersburg, Maryland 20899 (United States); University of Washington, Seattle, Washington 98195 (United States)

    2009-07-15T23:59:59.000Z

    The Russian-American experiment SAGE began to measure the solar neutrino capture rate with a target of gallium metal in December 1989. Measurements have continued with only a few brief interruptions since that time. In this article we present the experimental improvements in SAGE since its last published data summary in December 2001. Assuming the solar neutrino production rate was constant during the period of data collection, combined analysis of 168 extractions through December 2007 gives a capture rate of solar neutrinos with energy more than 233 keV of 65.4{sub -3.0}{sup +3.1} (stat) {sub -2.8}{sup +2.6} (syst) SNU. The weighted average of the results of all three Ga solar neutrino experiments, SAGE, Gallex, and GNO, is now 66.1{+-}3.1 SNU, where statistical and systematic uncertainties have been combined in quadrature. During the recent period of data collection a new test of SAGE was made with a reactor-produced {sup 37}Ar neutrino source. The ratio of observed to calculated rates in this experiment, combined with the measured rates in the three prior {sup 51}Cr neutrino-source experiments with Ga, is 0.87{+-}0.05. A probable explanation for this low result is that the cross section for neutrino capture by the two lowest-lying excited states in {sup 71}Ge has been overestimated. If we assume these cross sections are zero, then the standard solar model including neutrino oscillations predicts a total capture rate in Ga in the range of 63 SNU to 66 SNU with an uncertainty of about 4%, in good agreement with experiment. We derive the current value of the neutrino flux produced in the Sun by the proton-proton fusion reaction to be {phi}{sub pp}{sup {center_dot}}=(6.0{+-}0.8)x10{sup 10}/(cm{sup 2} s), which agrees well with the pp flux predicted by the standard solar model. Finally, we make several tests and show that the data are consistent with the assumption that the solar neutrino production rate is constant in time.

  12. Measurement of the solar neutrino capture rate with gallium metal. III: Results for the 2002--2007 data-taking period

    E-Print Network [OSTI]

    SAGE Collaboration; J. N. Abdurashitov; V. N. Gavrin; V. V. Gorbachev; P. P. Gurkina; T. V. Ibragimova; A. V. Kalikhov; N. G. Khairnasov; T. V. Knodel; I. N. Mirmov; A. A. Shikhin; E. P. Veretenkin; V. E. Yants; G. T. Zatsepin; T. J. Bowles; S. R. Elliott; W. A. Teasdale; J. S. Nico; B. T. Cleveland; J. F. Wilkerson

    2009-08-10T23:59:59.000Z

    The Russian-American experiment SAGE began to measure the solar neutrino capture rate with a target of gallium metal in Dec. 1989. Measurements have continued with only a few brief interruptions since that time. We give here the experimental improvements in SAGE since its last published data summary in Dec. 2001. Assuming the solar neutrino production rate was constant during the period of data collection, combined analysis of 168 extractions through Dec. 2007 gives a capture rate of solar neutrinos with energy more than 233 keV of 65.4 (+3.1)(-3.0) (stat) (+2.6)(-2.8) (syst) SNU. The weighted average of the results of all three Ga solar neutrino experiments, SAGE, Gallex, and GNO, is now 66.1 +/- 3.1 SNU, where statistical and systematic uncertainties have been combined in quadrature. During the recent period of data collection a new test of SAGE was made with a reactor-produced 37Ar neutrino source. The ratio of observed to calculated rates in this experiment, combined with the measured rates in the three prior 51Cr neutrino-source experiments with Ga, is 0.87 +/- 0.05. A probable explanation for this low result is that the cross section for neutrino capture by the two lowest-lying excited states in 71Ge has been overestimated. If we assume these cross sections are zero, then the standard solar model including neutrino oscillations predicts a total capture rate in Ga in the range of 63-66 SNU with an uncertainty of about 4%, in good agreement with experiment. We derive the current value of the neutrino flux produced in the Sun by the proton-proton fusion reaction to be (6.0 +/- 0.8) x 10^(10)/(cm^2 s), which agrees well with the pp flux predicted by the standard solar model. Finally, we show that the data are consistent with the assumption that the solar neutrino production rate is constant in time.

  13. SOLAR SEMINAR SERIES S P R I N G 2 0 1 3 P H O T O V O L T A I C S E M I N A R S E R I E S

    E-Print Network [OSTI]

    Ginzel, Matthew

    challenge for the success of copper indium gallium selenide (CIGS) photovoltaic cells. Co-evaporation yieldsSOLAR SEMINAR SERIES S P R I N G 2 0 1 3 P H O T O V O L T A I C S E M I N A R S E R I E S BILLY J spanning more than 30 years in the solar industry. He is an expert in the business and science

  14. CuIn1-xGaxS2 thin film solar cells with ZnxCd1-xS as heterojunction partner Bhaskar Kumar

    E-Print Network [OSTI]

    Sites, James R.

    80523 ABSTRACT Copper indium gallium sulfide, CuIn1-xGaxS2 (CIGS2) solar cells prepared with chemicalCuIn1-xGaxS2 thin film solar cells with ZnxCd1-xS as heterojunction partner Bhaskar Kumar 1 , Parag/heterojunction partner/ ZnO/Cr/Ag contact fingers solar cells of area ~0.44 cm 2 were fabricated at FSEC

  15. Formation of selenide, sulfide or mixed selenide-sulfide films on metal or metal coated substrates

    DOE Patents [OSTI]

    Eser, Erten; Fields, Shannon

    2012-05-01T23:59:59.000Z

    A process and composition for preventing cracking in composite structures comprising a metal coated substrate and a selenide, sulfide or mixed selenide sulfide film. Specifically, cracking is prevented in the coating of molybdenum coated substrates upon which a copper, indium-gallium diselenide (CIGS) film is deposited. Cracking is inhibited by adding a Se passivating amount of oxygen to the Mo and limiting the amount of Se deposited on the Mo coating.

  16. Modeling and simulation of CuIn{sub 1?x}Ga{sub x}Se{sub 2} based thin film solar cell

    SciTech Connect (OSTI)

    Kumari, S., E-mail: sarita.kumari132@gmail.com; Verma, A. S. [Department of Physics, Banasthali University, Rajasthan-304022 (India); Singh, P.; Gautam, R. [Department of Electronics and Communication, Krishna Institute of Engg. and Tech., Ghaziabad-201206 (India)

    2014-04-24T23:59:59.000Z

    In this work, CIGS (Copper Indium Gallium Diselenide) based solar cell structure has been simulated. We have been calculated short circuit current, open circuit voltage and efficiency of the cell. The thickness of the absorption layer is varied from 400 to 3000 nm, keeping the thickness of other layers unchanged. The effect of absorption layer thickness over cell performance has been analyzed and found that the efficiency increases upto 22% until the thickness of the absorption layer reaches around 2000 nm.

  17. Sandia National Laboratories: gallium nitride

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

    and Systems Dept.) recently published the article "Band offsets of La2O3 on (0001) GaN grown by reactive molecular-beam epitaxy" in Applied Physics Letters outlining research...

  18. VOLUME 76, NUMBER 8 P H Y S I C A L R E V I E W L E T T E R S 19 FEBRUARY 1996 Large Local-Field Corrections in Optical Rotatory Power of Quartz and Selenium

    E-Print Network [OSTI]

    Wilkins, John

    local fields are needed despite the vector character of light. A self-energy-corrected local-density for linearly polarized light. This phenomenon is described by the optical rotatory power r v nL 2 nR 2c, where-Field Corrections in Optical Rotatory Power of Quartz and Selenium Lars Jönsson,1 Zachary H. Levine,1,2 and John W

  19. Improvement of bias-stability in amorphous-indium-gallium-zinc-oxide thin-film transistors by using solution-processed Y{sub 2}O{sub 3} passivation

    SciTech Connect (OSTI)

    An, Sungjin; Mativenga, Mallory; Kim, Youngoo; Jang, Jin, E-mail: jjang@khu.ac.kr [Advanced Display Research Center, Department of Information Display, Kyung Hee University, Dongdaemun-gu, Seoul 130-701 (Korea, Republic of)

    2014-08-04T23:59:59.000Z

    We demonstrate back channel improvement of back-channel-etch amorphous-indium-gallium-zinc-oxide (a-IGZO) thin-film transistors by using solution-processed yttrium oxide (Y{sub 2}O{sub 3}) passivation. Two different solvents, which are acetonitrile (35%)?+?ethylene glycol (65%), solvent A and deionized water, solvent B are investigated for the spin-on process of the Y{sub 2}O{sub 3} passivation—performed after patterning source/drain (S/D) Mo electrodes by a conventional HNO{sub 3}-based wet-etch process. Both solvents yield devices with good performance but those passivated by using solvent B exhibit better light and bias stability. Presence of yttrium at the a-IGZO back interface, where it occupies metal vacancy sites, is confirmed by X-ray photoelectron spectroscopy. The passivation effect of yttrium is more significant when solvent A is used because of the existence of more metal vacancies, given that the alcohol (65% ethylene glycol) in solvent A may dissolve the metal oxide (a-IGZO) through the formation of alkoxides and water.

  20. Metal articles having ultrafine particles dispersed therein

    SciTech Connect (OSTI)

    Alexander, G.B.; Nadkarni, R.A.

    1992-07-28T23:59:59.000Z

    This patent describes a metal article of manufacture. It comprises: a metal selected from the group consisting of copper, silver, gold, lead, tin, nickel, zinc, cobalt, antimony, bismuth, iron, cadmium, chromium, germanium, gallium, selenium, tellurium, mercury, tungsten arsenic, manganese, iridium, indium, ruthenium, rhenium, rhodium, molybdenum, palladium, osmium and platinum; and a plurality of ultrafine particles.

  1. Influence of different sulfur to selenium ratios on the structural and electronic properties of Cu(In,Ga)(S,Se){sub 2} thin films and solar cells formed by the stacked elemental layer process

    SciTech Connect (OSTI)

    Mueller, B. J., E-mail: bjm.mueller@web.de [Robert Bosch GmbH, Corporate Research and Advance Engineering, Advanced Functional Materials and Microsystems, D-70839 Gerlingen (Germany); Institute of Micro- and Nanomaterials, University of Ulm, D-89081 Ulm (Germany); Zimmermann, C.; Haug, V., E-mail: veronika.haug@de.bosch.com; Koehler, T.; Zweigart, S. [Robert Bosch GmbH, Corporate Research and Advance Engineering, Advanced Functional Materials and Microsystems, D-70839 Gerlingen (Germany); Hergert, F. [Bosch Solar CISTech GmbH, D-14772 Brandenburg (Germany); Herr, U., E-mail: ulrich.herr@uni-ulm.de [Institute of Micro- and Nanomaterials, University of Ulm, D-89081 Ulm (Germany)

    2014-11-07T23:59:59.000Z

    In this study, we investigate the effect of different elemental selenium to elemental sulfur ratios on the chalcopyrite phase formation in Cu(In,Ga)(S,Se){sub 2} thin films. The films are formed by the stacked elemental layer process. The structural and electronic properties of the thin films and solar cells are analyzed by means of scanning electron microscopy, glow discharge optical emission spectrometry, X-ray diffraction, X-ray fluorescence, Raman spectroscopy, spectral photoluminescence as well as current-voltage, and quantum efficiency measurements. The influence of different S/(S+Se) ratios on the anion incorporation and on the Ga/In distribution is investigated. We find a homogenous sulfur concentration profile inside the film from the top surface to the bottom. External quantum efficiency measurements show that the band edge of the solar cell device is shifted to shorter wavelength, which enhances the open-circuit voltages. The relative increase of the open-circuit voltage with S/(S+Se) ratio is lower than expected from the band gap energy trend, which is attributed to the presence of S-induced defects. We also observe a linear decrease of the short-circuit current density with increasing S/(S+Se) ratio which can be explained by a reduced absorption. Above a critical S/(S+Se) ratio of around 0.61, the fill factor drops drastically, which is accompanied by a strong series resistance increase which may be attributed to changes in the back contact or p-n junction properties.

  2. Direct measurements of band gap grading in polycrystalline CIGS solar cells

    E-Print Network [OSTI]

    Heinrich, M P; Zhang, Y; Kiowski, O; Powalla, M; Lemmer, U; Slobodskyy, A

    2010-01-01T23:59:59.000Z

    We present direct measurements of depth-resolved band gap variations of CuIn(1-x)Ga(x)Se2 thin-film solar cell absorbers. A new measurement technique combining parallel measurements of local thin-film interference and spectral photoluminescence was developed for this purpose. We find sample-dependent correlation parameters between measured band gap depth and composition profiles, and emphasize the importance of direct measurements. These results bring a quantitative insight into the electronic properties of the solar cells and open a new way to analyze parameters that determine the efficiency of solar cells.

  3. Post-Deposition Treatment Boosts CIGS Solar Cell Performance (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2014-08-01T23:59:59.000Z

    NREL's use of potassium fluoride process improves the open-circuit voltage and conversion efficiency.

  4. Direct measurements of band gap grading in polycrystalline CIGS solar cells

    E-Print Network [OSTI]

    M. P. Heinrich; Z-H. Zhang; Y. Zhang; O. Kiowski; M. Powalla; U. Lemmer; A. Slobodskyy

    2010-09-20T23:59:59.000Z

    We present direct measurements of depth-resolved band gap variations of CuIn(1-x)Ga(x)Se2 thin-film solar cell absorbers. A new measurement technique combining parallel measurements of local thin-film interference and spectral photoluminescence was developed for this purpose. We find sample-dependent correlation parameters between measured band gap depth and composition profiles, and emphasize the importance of direct measurements. These results bring a quantitative insight into the electronic properties of the solar cells and open a new way to analyze parameters that determine the efficiency of solar cells.

  5. CIGS Thin-Film Solar Cell Research at NREL: FY04 Results and Accomplishments

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItem Not Found Item Not Found The itemAIR57451 Clean Energy Technologies A

  6. NREL: Awards and Honors - Lightweight, Flexible, Thin-Film CIGS PV Modules

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Saleshttp://www.fnal.gov/directorate/nalcal/nalcal02_07_05_files/nalcal.gifNREL NREL Refines MethodLightweight, Flexible, Thin-Film

  7. Statistical Methods for Enhanced Metrology in Semiconductor/Photovoltaic Manufacturing

    E-Print Network [OSTI]

    Zeng, Dekong

    2012-01-01T23:59:59.000Z

    VACUUM PROCESSING OF CIGS SOLAR CELLS ON FLEXIBLE POLYMERICcell………………………… Figure 2.5 CIGS based solar cell fabricationcells. Figure 2.5 CIGS based solar cell fabrication flow [

  8. The Effects of Non-Uniform Electronic Properties on Thin Film Photovoltaics

    E-Print Network [OSTI]

    Brown, Gregory Ferguson

    2011-01-01T23:59:59.000Z

    material   systems.   CIGS  solar  cells  grown  at  the  the  depth  of  the  CIGS  solar  cells  improve  carrier  length  in  CIGS  solar  cells  has  no  correlation  with  

  9. Self- and zinc diffusion in gallium antimonide

    E-Print Network [OSTI]

    Nicols, Samuel Piers

    2002-01-01T23:59:59.000Z

    5, 265 (1957). S. Glasstone, K . Laidler, H . Eyring, Thequantity D . Henry Eyring [Glasstone, Eyring (1941)] was the

  10. Superconductive silicon nanowires using gallium beam lithography.

    SciTech Connect (OSTI)

    Henry, Michael David; Jarecki, Robert Leo,

    2014-01-01T23:59:59.000Z

    This work was an early career LDRD investigating the idea of using a focused ion beam (FIB) to implant Ga into silicon to create embedded nanowires and/or fully suspended nanowires. The embedded Ga nanowires demonstrated electrical resistivity of 5 m-cm, conductivity down to 4 K, and acts as an Ohmic silicon contact. The suspended nanowires achieved dimensions down to 20 nm x 30 nm x 10 m with large sensitivity to pressure. These structures then performed well as Pirani gauges. Sputtered niobium was also developed in this research for use as a superconductive coating on the nanowire. Oxidation characteristics of Nb were detailed and a technique to place the Nb under tensile stress resulted in the Nb resisting bulk atmospheric oxidation for up to years.

  11. Electronic properties of gallium nitride nanowires

    E-Print Network [OSTI]

    Yoon, Joonah

    2008-01-01T23:59:59.000Z

    This thesis presents a systematic study of the electrical transport in GaN nanowires. Particularly, the effect of the surrounding dielectric on the conductivity of GaN nanowires is experimentally shown for the first time. ...

  12. Efficient wireless charging with gallium nitride FETs

    E-Print Network [OSTI]

    Yeh, Theresa (Theresa I.)

    2014-01-01T23:59:59.000Z

    Though wireless charging is more convenient than traditional wired charging methods, it is currently less efficient. This not only wastes power but can also result in a longer charging time. Improving the efficiency of ...

  13. Interactions of gallium with zircaloy cladding

    E-Print Network [OSTI]

    Mitchell, Lee Josey

    1999-01-01T23:59:59.000Z

    like to thank Dr. Ron R. Hart, my advisor, for his help and direction through out the project. I would like to acknowledge J. Shipp for his help during the RBS analysis. I would also like to thank Dr. R. Guillemette for his help with the Electron... CHAPTER I INTRODUCTION The accepted options for the disposition of weapons-grade plutonium (WGPu) are immobilization or conversion to a mixed-oxide (MOX) reactor fuel. There are two benefits of conversion, one, the plutonium can't be converted back...

  14. Smooth cubic commensurate oxides on gallium nitride

    SciTech Connect (OSTI)

    Paisley, Elizabeth A.; Gaddy, Benjamin E.; LeBeau, James M.; Shelton, Christopher T.; Losego, Mark D.; Mita, Seiji; Collazo, Ramón; Sitar, Zlatko; Irving, Douglas L.; Maria, Jon-Paul, E-mail: jpmaria@ncsu.edu [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Biegalski, Michael D.; Christen, Hans M. [Center for Nanophase Materials Science, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2014-02-14T23:59:59.000Z

    Smooth, commensurate alloys of ?111?-oriented Mg{sub 0.52}Ca{sub 0.48}O (MCO) thin films are demonstrated on Ga-polar, c+ [0001]-oriented GaN by surfactant-assisted molecular beam epitaxy and pulsed laser deposition. These are unique examples of coherent cubic oxide|nitride interfaces with structural and morphological perfection. Metal-insulator-semiconductor capacitor structures were fabricated on n-type GaN. A comparison of leakage current density for conventional and surfactant-assisted growth reveals a nearly 100× reduction in leakage current density for the surfactant-assisted samples. HAADF-STEM images of the MCO|GaN interface show commensurate alignment of atomic planes with minimal defects due to lattice mismatch. STEM and DFT calculations show that GaN c/2 steps create incoherent boundaries in MCO over layers which manifest as two in-plane rotations and determine consequently the density of structural defects in otherwise coherent MCO. This new understanding of interfacial steps between HCP and FCC crystals identifies the steps needed to create globally defect-free heterostructures.

  15. Development of gallium nitride power transistors

    E-Print Network [OSTI]

    Piedra, Daniel, M. Eng. Massachusetts Institute of Technology

    2011-01-01T23:59:59.000Z

    GaN-based high-voltage transistors have outstanding properties for the development of ultra-high efficiency and compact power electronics. This thesis describes a new process technology for the fabrication of GaN power ...

  16. Copper Indium Gallium Diselenide | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't Your Destiny: Theof"Wave theJuly 30, 2013Department of Energy CoordinatingPhotovoltaics

  17. Syntheses, crystal structures and optical properties of the first strontium selenium(IV) and tellurium(IV) oxychlorides: Sr{sub 3}(SeO{sub 3})(Se{sub 2}O{sub 5})Cl{sub 2} and Sr{sub 4}(Te{sub 3}O{sub 8})Cl{sub 4}

    SciTech Connect (OSTI)

    Jiang Hailong [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Mao Jianggao [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China)], E-mail: mjg@fjirsm.ac.cn

    2008-02-15T23:59:59.000Z

    Two new quaternary strontium selenium(IV) and tellurium(IV) oxychlorides, namely, Sr{sub 3}(SeO{sub 3})(Se{sub 2}O{sub 5})Cl{sub 2} and Sr{sub 4}(Te{sub 3}O{sub 8})Cl{sub 4}, have been prepared by solid-state reaction. Sr{sub 3}(SeO{sub 3})(Se{sub 2}O{sub 5})Cl{sub 2} features a three-dimensional (3D) network structure constructed from strontium(II) interconnected by Cl{sup -}, SeO{sub 3}{sup 2-} as well as Se{sub 2}O{sub 5}{sup 2-} anions. The structure of Sr{sub 4}(Te{sub 3}O{sub 8})Cl{sub 4} features a 3D network in which the strontium tellurium oxide slabs are interconnected by bridging Cl{sup -} anions. The diffuse reflectance spectrum measurements and results of the electronic band structure calculations indicate that both compounds are wide band-gap semiconductors. - Graphical abstract: Solid-state reactions of SrO, SrCl{sub 2}, and SeO{sub 2} or TeO{sub 2} in different molar ratios and under different temperatures lead to two new strontium selenium(IV) or tellurium(IV) oxychlorides with two different types of structures, namely, Sr{sub 3}(SeO{sub 3})(Se{sub 2}O{sub 5})Cl{sub 2} and Sr{sub 4}(Te{sub 3}O{sub 8})Cl{sub 4}. Both compounds are wide band-gap semiconductors based on the diffuse reflectance spectra and the electronic band structures.

  18. Preparation of cuxinygazsen (X=0-2, Y=0-2, Z=0-2, N=0-3) precursor films by electrodeposition for fabricating high efficiency solar cells

    DOE Patents [OSTI]

    Bhattacharya, Raghu N. (Littleton, CO); Contreras, Miguel A. (Golden, CO); Keane, James (Lakewood, CO); Tennant, Andrew L. (Denver, CO); Tuttle, John R. (Denver, CO); Ramanathan, Kannan (Lakewood, CO); Noufi, Rommel (Golden, CO)

    1998-03-24T23:59:59.000Z

    High quality thin films of copper-indium-gallium-diselenide useful in the production of solar cells are prepared by electrodepositing at least one of the constituent metals onto a glass/Mo substrate, followed by physical vapor deposition of copper and selenium or indium and selenium to adjust the final stoichiometry of the thin film to approximately Cu(In,Ga)Se.sub.2. Using an AC voltage of 1-100 KHz in combination with a DC voltage for electrodeposition improves the morphology and growth rate of the deposited thin film. An electrodeposition solution comprising at least in part an organic solvent may be used in conjunction with an increased cathodic potential to increase the gallium content of the electrodeposited thin film.

  19. Selenium containing molecules from Astragalus racemosus

    E-Print Network [OSTI]

    Price, Jeanine Ekelund

    1976-01-01T23:59:59.000Z

    ) Ether (reagent grade), ammonium formate (99. 6X purity), hydrochloric acid (technical grade), oxalic acid, sucrose and glucose were purchased from the Fisher Scientific Company. (2) Formic acid (90?) and aniline were purchased from Matheson Coleman... by diluting 70 ml of the concentrated acid to 210 ml. (6) Reagent A, used to color the sugar spots on the paper chromatograms, was prepared by dissolving 2. 52 g of oxalic acid in 100 ml of ethanol and mixing 1. 86 ml of aniline in 100 ml of ethanol...

  20. 269Maher: Selenium in macroalgae Botanica Marina

    E-Print Network [OSTI]

    Canberra, University of

    specimenswere washed with distilled water to re- movesaltsand smallinvertebrates.After homogeni- zation usinga blender, subsampleswere freezedried and ground to passa 200 11mseive. Sampleswere thenstored in air for macroal- gae (Fries 1982) while biochemical fractionation of two microalgae (Wrench 1978) and a macroalga

  1. What You Need to Know about Selenium

    E-Print Network [OSTI]

    Hopkins, William A.

    is a common by-product of several core economic activities: coal- fired generation of electricity; refining of crude oil; mining of coal, phosphate, copper, and uranium~ and irrigated agriculture. Because these industries are likely to continue and grow into the foreseeable future, the potential for large- scale

  2. Emerging Opportunities in Management of Selenium

    E-Print Network [OSTI]

    will growintheyearsaheadwiththeexploitationofcoalandsimilar fossil fuels, irrigation in semiarid regions, and mining of phosphate ore (9). Finally, Se and redistribution in a water body determine the concentrations that result from mass inputs. Speciation affects

  3. Three approaches to economical photovoltaics: conformal Cu2S, organic luminescent films, and PbSe nanocrystal superlattices

    E-Print Network [OSTI]

    Carbone, Ian Anthony

    2013-01-01T23:59:59.000Z

    oxygen and water. Conventional CIGS solar cells must also bereal possibility. CIGS solar cells suffer similar parasitic

  4. Comparative alternative materials assessment to screen toxicity hazards in the life cycle of CIGS thin film photovoltaics

    E-Print Network [OSTI]

    Eisenberg, DA; Yu, M; Lam, CW; Ogunseitan, OA; Schoenung, JM

    2013-01-01T23:59:59.000Z

    nickel alloy Titanium Polyimide Flexible polymers Notes:hazard substrate material is: polyimide. The only metal backdioxide Molybdenum Polyimide Notes: This is a subset of all

  5. High Efficiency CdTe and CIGS Thin Film Solar Cells: Highlights of the Technologies Challenges (Presentation)

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItem Not Found Item Not Found The itemAIR57451DOE/SC0002390dVandHEATINGDOBEH -0454

  6. Structural Integration of Silicon Solar Cells and Lithium-ion Batteries Using Printed Electronics

    E-Print Network [OSTI]

    Kang, Jin Sung

    2012-01-01T23:59:59.000Z

    better mechanical durability. CIGS solar cell has about 20%5]. However, CIGS solar cells degrade with humidity andSelenide (CIGS)[3] and organic polymer[4] solar cells are

  7. Laser Induced Breakdown Spectroscopy and Applications Toward Thin Film Analysis

    E-Print Network [OSTI]

    Owens, Travis Nathan

    2011-01-01T23:59:59.000Z

    of CIGS solar cells . Conclusions . . . . . . . . . . . . .roll-to-roll printed CIGS solar cell on aluminum substrateDepth profiling of CIGS solar cell using a nanosecond Nd:YAG

  8. Femtosecond laser processing of photovoltaic and transparent materials

    E-Print Network [OSTI]

    Ahn, Sanghoon

    2013-01-01T23:59:59.000Z

    of   'ink   based'   CIGS   solar   cells/modules.    Ink-­?based'   CIGS   solar   cells   on   lightweight  Figure 4-2. Ink-based CIGS solar cell, cross section by

  9. Creating CZTS Thin Films Via Stacked Metallic CVD and Sulfurization

    E-Print Network [OSTI]

    Bielecki, Anthony

    2013-01-01T23:59:59.000Z

    film solar cells. CIGS solar cell efficiencies have beenCIGS, making it a favorable choice for thin-film solar cells.thin film solar cell [3]. However, use of CIGS has a number

  10. Molecular solution processing of metal chalcogenide thin film solar cells

    E-Print Network [OSTI]

    Yang, Wenbing

    2013-01-01T23:59:59.000Z

    3-6,3-7] Chalcopyrite CIGS solar cells, without introducingperformance CISS and CIGS solar cells with efficiencies uptellurium might impede CIGS/CdTe solar cells from reaching

  11. Selective Chemistry of Metal Oxide Atomic Layer Deposition on Si Based Substrate Surfaces

    E-Print Network [OSTI]

    Guo, Lei

    2015-01-01T23:59:59.000Z

    of the solar cells. In CIGS solar cells, the buffer layers,encapsulation of CIGS and OPV solar cells[24, 25], barrierof flexible CIGS and OPV solar cells, robust, transparent

  12. Fully Solution-Processed Copper Chalcopyrite Thin Film Solar Cells: Materials Chemistry, Processing, and Device Physics

    E-Print Network [OSTI]

    Chung, Choong-Heui

    2012-01-01T23:59:59.000Z

    cm 2 ) efficiency CIGS solar cells taken from reference [and 20.3% efficiency CIGS solar cells [6] through the use ofcm 2 ) efficiency CIGS solar cells taken from reference [6].

  13. FTIR and FT-PL Spectroscopic Analysis of TPV Materials and Devices

    SciTech Connect (OSTI)

    Webb, J. D.; Gedvilas, L. M.; Olson, M. R.; Wu, X.; Duda, A.; Wanlass, M. W.; Jones, K. M.

    1998-10-28T23:59:59.000Z

    Impurities in cadmium sulfide (CdS) films are a concern in the fabrication of copper (indium, gallium) diselenide (CIGS) and cadmium telluride (CdTe) photovoltaic devices. Devices incorporating chemical-bath-deposited (CBD) CdS are comparable in quality to devices incorporating purer CdS films grown using vacuum deposition techniques, despite the higher impurity concentrations typically observed in the CBD CdS films. In this paper, we summarize and review the results of Fourier transform infrared (FTIR), Auger, electron microprobe, and X-ray photoelectron spectroscopic (XPS) analyses of the impurities in CBD CdS films. We show that these impurities differ as a function of substrate type and film deposition conditions. We also show that some of these impurities exist as 102 micron-scale precipitates.

  14. Morphology Control of Layer-Structured Gallium Selenide Nanowires

    E-Print Network [OSTI]

    Cui, Yi

    for stable photocathodes and battery electrodes. We report the controlled synthesis and characterization cells3 and solid-state batteries.4 Their one-dimensional nanowire (NW) structures may afford better

  15. Electronic Transport Characteristics of Gallium Nitride Nanowire-based Nanocircuits

    E-Print Network [OSTI]

    Ayres, Virginia

    . The measurements indicate a working field effect transistor utilizing a global back gate configuration. Very high and drain contacts were patterned using electron beam lithography, with Ti/Au used for the conducting source and drain material. The backside of the wafer was stripped of silicon dioxide using hydrofluoric acid and Ti

  16. Neutron irradiation effects on metal-gallium nitride contacts

    SciTech Connect (OSTI)

    Katz, Evan J.; Lin, Chung-Han; Zhang, Zhichun [Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Qiu, Jie; Cao, Lei [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Mishra, Umesh K. [Departments of Electrical and Computer Engineering and Materials Science and Engineering University of California, Santa Barbara, California 93106 (United States); Brillson, Leonard J., E-mail: brillson.1@osu.edu [Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Department of Physics and Center for Materials Research, The Ohio State University, Columbus, Ohio 43210 (United States)

    2014-03-28T23:59:59.000Z

    We have measured the effect of fast and thermal neutrons on GaN Schottky barriers and ohmic contacts using current–voltage and transmission line method electrical techniques, optical, atomic force and scanning electron microscopy morphological techniques, and X-ray photoemission spectroscopy chemical techniques. These studies reveal a 10{sup 15}?n/cm{sup 2} neutron threshold for Schottky barrier ideality factor increases, a 10{sup 15}?n/cm{sup 2} fast plus thermal neutron threshold for ohmic contact sheet and contact resistance increases, and 10{sup 16}?n/cm{sup 2} neutron fluence threshold for major device degradation identified with thermally driven diffusion of Ga and N into the metal contacts and surface phase changes. These results demonstrate the need for protecting metal-GaN contacts in device applications subject to neutron radiation.

  17. Neutron irradiation effects on gallium nitride-based Schottky diodes

    SciTech Connect (OSTI)

    Lin, Chung-Han; Katz, Evan J.; Zhang, Zhichun [Department of Electrical and Computer Engineering, The Ohio State University, Columbus Ohio 43210 (United States)] [Department of Electrical and Computer Engineering, The Ohio State University, Columbus Ohio 43210 (United States); Qiu, Jie; Cao, Lei [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, Ohio 43210 (United States)] [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Mishra, Umesh K. [Departments of Electrical and Computer Engineering and Materials Science and Engineering, University of California, Santa Barbara, California 93106 (United States)] [Departments of Electrical and Computer Engineering and Materials Science and Engineering, University of California, Santa Barbara, California 93106 (United States); Brillson, Leonard J. [Department of Electrical and Computer Engineering, The Ohio State University, Columbus Ohio 43210 (United States) [Department of Electrical and Computer Engineering, The Ohio State University, Columbus Ohio 43210 (United States); Department of Physics and Center for Materials Research, The Ohio State University, Columbus, Ohio 43210 (United States)

    2013-10-14T23:59:59.000Z

    Depth-resolved cathodoluminescence spectroscopy (DRCLS), time-resolved surface photovoltage spectroscopy, X-ray photoemission spectroscopy (XPS), and current-voltage measurements together show that fast versus thermal neutrons differ strongly in their electronic and morphological effects on metal-GaN Schottky diodes. Fast and thermal neutrons introduce GaN displacement damage and native point defects, while thermal neutrons also drive metallurgical reactions at metal/GaN interfaces. Defect densities exhibit a threshold neutron fluence below which thermal neutrons preferentially heal versus create new native point defects. Scanning XPS and DRCLS reveal strong fluence- and metal-dependent electronic and chemical changes near the free surface and metal interfaces that impact diode properties.

  18. Superconductivity in gallium-substituted Ba8Si46 clathrates

    E-Print Network [OSTI]

    Li, Yang; Zhang, Ruihong; Liu, Yang; Chen, Ning; Luo, Z. P.; Ma, Xingqiao; Cao, Guohui; Feng, Z. S.; Hu, Chia-Ren; Ross, Joseph H., Jr.

    2007-01-01T23:59:59.000Z

    superconductor, with an onset at T-C approximate to 3.3 K. For x=10 and higher, no superconductivity was observed down to T=1.8 K. This represents a strong suppression of superconductivity with increasing Ga content, compared to Ba8Si46 with T-C approximate to 8...

  19. Production of gallium-66, a positron emitting nuclide for radioimmunotherapy

    SciTech Connect (OSTI)

    Mirzadeh, S. (Oak Ridge National Lab., TN (United States)); Chu, Y.Y. (Brookhaven National Lab., Upton, NY (United States))

    1991-01-01T23:59:59.000Z

    Excitation functions for production of {sup 66}Ga via {alpha}-induced nuclear reactions on enriched {sup 66}Zn and {sup 64}Zn have been measured with E{sub {alpha}}{le}27.3 MeV and E{sub {alpha}}{le}43.7 MeV employing the stack-thin target technique. In addition, the induced activity of {sup 67} Ga in the same sets of targets allowed an evaluation of the excitation functions of the corresponding nuclear reactions.

  20. Production of gallium-66, positron emitting nuclide for radioimmumotherapy

    SciTech Connect (OSTI)

    Mirzadeh, S. (Oak Ridge National Lab., TN (USA)); Chu, Yung Yee (Brookhaven National Lab., Upton, NY (USA))

    1991-01-01T23:59:59.000Z

    Excitation functions for production of {sup 66}Ga via {alpha}-induced nuclear reactions on enriched {sup 66}Zn have been measured with E{sub {alpha}}{le}27.3 MeV and E{sub {alpha}}{le}43.7 MeV employing the stack-thin target technique. In addition, the induced activity of {sup 67}Ga in the same sets of targets allowed an evaluation of the excitation functions of the corresponding nuclear reactions. 17 refs., 2 figs., 2 tabs.

  1. Production of gallium-66, a positron emitting nuclide for radioimmunotherapy

    SciTech Connect (OSTI)

    Mirzadeh, S. [Oak Ridge National Lab., TN (United States); Chu, Y.Y. [Brookhaven National Lab., Upton, NY (United States)

    1991-12-31T23:59:59.000Z

    Excitation functions for production of {sup 66}Ga via {alpha}-induced nuclear reactions on enriched {sup 66}Zn and {sup 64}Zn have been measured with E{sub {alpha}}{le}27.3 MeV and E{sub {alpha}}{le}43.7 MeV employing the stack-thin target technique. In addition, the induced activity of {sup 67} Ga in the same sets of targets allowed an evaluation of the excitation functions of the corresponding nuclear reactions.

  2. Advanced Epi Tools for Gallium Nitride Light Emitting Diode Devices

    SciTech Connect (OSTI)

    Patibandla, Nag; Agrawal, Vivek

    2012-12-01T23:59:59.000Z

    Over the course of this program, Applied Materials, Inc., with generous support from the United States Department of Energy, developed a world-class three chamber III-Nitride epi cluster tool for low-cost, high volume GaN growth for the solid state lighting industry. One of the major achievements of the program was to design, build, and demonstrate the world’s largest wafer capacity HVPE chamber suitable for repeatable high volume III-Nitride template and device manufacturing. Applied Materials’ experience in developing deposition chambers for the silicon chip industry over many decades resulted in many orders of magnitude reductions in the price of transistors. That experience and understanding was used in developing this GaN epi deposition tool. The multi-chamber approach, which continues to be unique in the ability of the each chamber to deposit a section of the full device structure, unlike other cluster tools, allows for extreme flexibility in the manufacturing process. This robust architecture is suitable for not just the LED industry, but GaN power devices as well, both horizontal and vertical designs. The new HVPE technology developed allows GaN to be grown at a rate unheard of with MOCVD, up to 20x the typical MOCVD rates of 3{micro}m per hour, with bulk crystal quality better than the highest-quality commercial GaN films grown by MOCVD at a much cheaper overall cost. This is a unique development as the HVPE process has been known for decades, but never successfully commercially developed for high volume manufacturing. This research shows the potential of the first commercial-grade HVPE chamber, an elusive goal for III-V researchers and those wanting to capitalize on the promise of HVPE. Additionally, in the course of this program, Applied Materials built two MOCVD chambers, in addition to the HVPE chamber, and a robot that moves wafers between them. The MOCVD chambers demonstrated industry-leading wavelength yield for GaN based LED wafers and industry-leading uptime enabled in part by a novel in-situ cleaning process developed in this program.

  3. Superconductivity in gallium-substituted Ba8Si46 clathrates 

    E-Print Network [OSTI]

    Li, Yang; Zhang, Ruihong; Liu, Yang; Chen, Ning; Luo, Z. P.; Ma, Xingqiao; Cao, Guohui; Feng, Z. S.; Hu, Chia-Ren; Ross, Joseph H., Jr.

    2007-01-01T23:59:59.000Z

    superconductor, with an onset at T-C approximate to 3.3 K. For x=10 and higher, no superconductivity was observed down to T=1.8 K. This represents a strong suppression of superconductivity with increasing Ga content, compared to Ba8Si46 with T-C approximate to 8...

  4. Rutherford backscattering analysis of gallium implanted 316 stainless steel 

    E-Print Network [OSTI]

    Ortensi, Javier

    2000-01-01T23:59:59.000Z

    Ion implantation of Ga ions into 316 stainless steel was performed at fluences ranging from 8x10ą? to 10ą? ions/cm˛. The depth profile of Ga in the steel was analyzed via Rutherford Backscattering and ToFSIMS. The surface effects were...

  5. Strongly localized excitons in gallium nitride C. Wetzel,a)

    E-Print Network [OSTI]

    Wetzel, Christian M.

    report on strong excitonic luminescence in wurtzite GaN at 3.309 and 3.365 eV T 6 K . These lines lie and characterization of excitonic luminescence transitions in wurtzite GaN about 150 meV below the fundamental elec transitions at 3.309 and 3.365 eV. Wurtzite GaN epilayers were grown by a high tempera- ture vapor phase

  6. GALLIUM--1997 29.1 By Deborah A. Kramer

    E-Print Network [OSTI]

    players. They also are used in short-range fiber optic communications systems, satellite communicationsAs is manufactured into optoelectronic devices (LED's, laser diodes, photodetectors, and solar cells) and integrated energy to a coherent light output. Laser diodes, also called semiconductor lasers or injection laser

  7. Monolithic series-connected gallium arsenide converter development

    SciTech Connect (OSTI)

    Spitzer, M.B.; McClelland, R.W.; Dingle, B.D.; Dingle, J.E.; Hill, D.S. (Kopin Corp., Taunton, MA (United States)); Rose, B.H. (Sandia National Labs., Albuquerque, NM (United States))

    1991-01-01T23:59:59.000Z

    We report the development of monolithic GaAs photovoltaic devices intended to convert light generated by a laser or other bright source to electricity. The converters described here can provide higher operating voltage than is possible using a single-junction converter, owing to use of a monolithic circuit that forms a planar series-connected string of single-junction sub-cells. This planar monolithic circuit is arranged to deliver the desired voltage and current during operation at the maximum power point. The paper describes two-, six-, and twelve-junction converters intended for illumination by a laser diode with a wavelength of 0.8 {mu}m. Design and characterization data are presented for optical power in the range of 100 mW to 1 W. The best conversion efficiency exceeds 50%. 9 refs., 4 figs., 2 tabs.

  8. Fabrication of a gated gallium arsenide heterostructure resonant tunneling diode 

    E-Print Network [OSTI]

    Kinard, William Brian

    1989-01-01T23:59:59.000Z

    ) William Brian Kinard, B. S, Texas A&M University Chair of Advisory Committee: Mark H. Weichold The objective of this research was to design and fabricate a device capable of electrically contrulhng current through a vertical resonant tunneling diode.... Addi- tionally, this modulation of current must not aB'ect the normal cperation of the resonant tunneling diode such as shifting resonant bias. Device arrays of various sizes were successfully 1'abricated for the first time utilizing unique...

  9. Rutherford backscattering analysis of gallium implanted 316 stainless steel

    E-Print Network [OSTI]

    Ortensi, Javier

    2000-01-01T23:59:59.000Z

    % was attained at 300 [] and deeper. The possible enhanced diffusion of Ga was observed, but not necessarily through the grain boundaries. Although there was no indication of compound formation, significant pitting was observed at high fluences. Repassivation...

  10. Gallium Nitride Integrated Gas/Temperature Sensors for

    E-Print Network [OSTI]

    precision and accuracy · Field test for reliability and lifetime · 1) Sensor Needs and Requirements://www.ott.doe.gov/pdfs/sensor_needs.pdf #12;4 Approach GaN based devices and circuits are an attractive option for high temperature electronic) and hydrogen (30-70%) 80% Complete 2- Determine confounding effects due to multiple components 80% Complete 3

  11. High Quality, Low Cost Bulk Gallium Nitride Substrates Grown...

    Energy Savers [EERE]

    silicon Widespread adoption of efficient load architectures enabled by GaN-based power electronics and lighting can lead to a 25% reduction in world energy consumption ...

  12. Formation mechanisms of spatially-directed zincblende gallium nitride nanocrystals

    SciTech Connect (OSTI)

    Wood, A. W. [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States); Collino, R. R. [Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); Cardozo, B. L. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); Naab, F. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States); Wang, Y. Q. [Materials Science and Technology Division, Los Alamos National Lab, Los Alamos, New Mexico 87545 (United States); Goldman, R. S. [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States); Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States)

    2011-12-15T23:59:59.000Z

    We report on the spatially selective formation of GaN nanocrystals embedded in GaAs. Broad-area N{sup +} implantation followed by rapid thermal annealing leads to the formation of nanocrystals at the depth of maximum ion damage. With additional irradiation using a Ga{sup +} focused ion beam, selective lateral positioning of the nanocrystals within the GaAs matrix is observed in isolated regions of increased vacancy concentration. Following rapid thermal annealing, the formation of zincblende GaN is observed in the regions of highest vacancy concentration. The nucleation of zincblende nanocrystals over the wurtzite phase of bulk GaN is consistent with the predictions of a thermodynamic model for the nanoscale size-dependence of GaN nucleation.

  13. abdominal gallium-67 citrate: Topics by E-print Network

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

    species (bigeye, Thunnus obesus; yellowfin, T. albacares; and skipjack, Katsuwonus pelamis) Environmental Sciences and Ecology Websites Summary: : 26 October 2004 Key words:...

  14. aluminium gallium indium: Topics by E-print Network

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

    on which all indium abundance studies are based, both for the quiet-sun and the sunspot umbra spectrum, employing standard atmosphere models and accounting for hyperfine structure...

  15. aluminum gallium indium: Topics by E-print Network

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

    on which all indium abundance studies are based, both for the quiet-sun and the sunspot umbra spectrum, employing standard atmosphere models and accounting for hyperfine structure...

  16. amorphous indium gallium: Topics by E-print Network

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

    on which all indium abundance studies are based, both for the quiet-sun and the sunspot umbra spectrum, employing standard atmosphere models and accounting for hyperfine structure...

  17. Gallium Arsenide (GaAs) EDWARD D. PALIK

    E-Print Network [OSTI]

    Pulfrey, David L.

    constants of pure (semi-insulating) GaAs are derived from a number of papers including the far-infrared at. [4]; the near-IR work of Pikhtin and Yas'kov [5]; the calorim- etry work of Christensen et al. [6 reflection work of Philipp and Ehrenreich [9]; and the synchrotron transmission work of Cardona et al. [10

  18. Broadband electrooptic modulators based on gallium arsenide materials

    E-Print Network [OSTI]

    Shamir, Orit A

    2012-01-01T23:59:59.000Z

    Optical Arbitrary Waveform Generation (OAWG) combines frequency combs and frequency-by- frequency pulse shapers to synthesize optical waveforms. The OAWG technique has a wide variety of applications, ranging from high ...

  19. Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide...

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

    Structural vacancies are a source of numerous interesting structural, electronic, and optical properties, and materials scientists often rely them as an important building...

  20. Self-aligned submicron gate length gallium arsenide MESFET 

    E-Print Network [OSTI]

    Huang, Hsien-Ching

    1987-01-01T23:59:59.000Z

    38 21. Proximity cap annealing . 22. Temperature profile of post implant anneal 46 47 23. 24. 25. 26. 27. 28. 29. 30. "Pits" or holes in GaAs post implant anneal without sacrificial cap Silicon monoxide source (bafile box) used.... 16(b)). The bottom resist layer is then further etched in the oxygen plasma to produce undercutting for the desire gate structure. The amount of undercut is determined by the desired length of the gate and is the width of the remaining resist...

  1. Process for growing epitaxial gallium nitride and composite wafers

    DOE Patents [OSTI]

    Weber, Eicke R.; Subramanya, Sudhir G.; Kim, Yihwan; Kruger, Joachim

    2003-05-13T23:59:59.000Z

    A novel growth procedure to grow epitaxial Group III metal nitride thin films on lattice-mismatched substrates is proposed. Demonstrated are the quality improvement of epitaxial GaN layers using a pure metallic Ga buffer layer on c-plane sapphire substrate. X-ray rocking curve results indicate that the layers had excellent structural properties. The electron Hall mobility increases to an outstandingly high value of .mu.>400 cm.sup.2 /Vs for an electron background concentration of 4.times.10.sup.17 cm.sup.-3.

  2. Growth and structure of sputtered gallium nitride films

    SciTech Connect (OSTI)

    Yadav, Brajesh S.; Major, S. S.; Srinivasa, R. S. [Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076 (India); Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai 400076 (India)

    2007-10-01T23:59:59.000Z

    GaN films have been deposited by radio frequency sputtering of a GaAs target with pure nitrogen. The growth, composition, and structure of the films deposited on quartz substrates have been studied by x-ray diffraction, transmission electron microscopy, and Raman spectroscopy. Films deposited below 300 deg. C are amorphous and As rich. Above 300 deg. C, polycrystalline, hexagonal GaN is formed, along with As rich amorphous phase, which reduces with increasing substrate temperature. At a substrate temperature of 700 deg. C, GaN films, practically free of amorphous phase, and As (<0.5 at. %) are formed. The preferred orientation depends strongly on the substrate temperature and is controlled by surface diffusion of adatoms during growth stage. Below 500 deg. C, the surface diffusion between planes dominates and results in the (1011) preferred orientation. Above 500 deg. C, the surface diffusion between grains takes over and results in (0002) preferred orientation.

  3. Electrochemical Solution Growth: Gallium Nitride Crystal Growth - Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField Campaign:INEAWater Use

  4. Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron SpinPrincetonUsing Maps to Predict4Vacancy announcements Alumni

  5. Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron SpinPrincetonUsing Maps to Predict4Vacancy announcements

  6. Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron SpinPrincetonUsing Maps to Predict4Vacancy announcementsVacancy-Induced

  7. Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron SpinPrincetonUsing Maps to Predict4Vacancy

  8. Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron SpinPrincetonUsing Maps to Predict4VacancyVacancy-Induced Nanoscale Wire

  9. Light-Emitting Diodes on Semipolar Bulk Gallium Nitride Substrate |

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page onYouTube YouTube Note: Since the.pdfBreaking ofOil & Gas »ofMarketing | Department ofEnergy Nuclear

  10. Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del SolStrengthening aTurbulenceUtilize Available Resources Print AsVacancy-Induced

  11. High-Quality, Low-Cost Bulk Gallium Nitride Substrates

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't YourTransport(Fact Sheet), GeothermalGridHYDROGEND D e e p p a a r rRancho Cordoba,High-Quality,

  12. Flexible Ultra Moisture Barrier Film for Thin-Film Photovoltaic Applications

    SciTech Connect (OSTI)

    David M. Dean

    2012-10-30T23:59:59.000Z

    Flexible Thin-film photovoltaic (TFPV) is a low cost alternative to incumbent c-Si PV products as it requires less volume of costly semiconductor materials and it can potentially reduce installation cost. Among the TFPV options, copper indium gallium diselenide (CIGS) has the highest efficiency and is believed to be one of the most attractive candidates to achieve PV cost reduction. However, CIGS cells are very moisture sensitive and require module water vapor transmission rate (WVTR) of less than 1x10-4 gram of water per square meter per day (g-H2O/m2/day). Successful development and commercialization of flexible transparent ultra moisture barrier film is the key to enable flexible CIGS TFPV products, and thus enable ultimate PV cost reduction. At DuPont, we have demonstrated at lab scale that we can successfully make polymer-based flexible transparent ultra moisture barrier film by depositing alumina on polymer films using atomic layer deposition (ALD) technology. The layer by layer ALD approach results in uniform and amorphous structure which effectively reduces pinhole density of the inorganic coating on the polymer, and thus allow the fabrication of flexible barrier film with WVTR of 10-5 g-H2O/m2/day. Currently ALD is a time-consuming process suitable only for high-value, relatively small substrates. To successfully commercialize the ALD-on-plastic technology for the PV industry, there is the need to scale up this technology and improve throughput. The goal of this contract work was to build a prototype demonstrating that the ALD technology could be scaled-up for commercial use. Unfortunately, the prototype failed to produce an ultra-barrier film by the close of the project.

  13. Spectroscopic evidence for a surface layer in CuInSe2 : Cu deficiency

    E-Print Network [OSTI]

    Han, Sung-Ho; Hasoon, Falah S.; Hermann, Allen M.; Levi, Dean H.

    2007-01-01T23:59:59.000Z

    labora- tory thin-?lm PX-CIGS solar cells has surpassed 19%.?CIGS? is used as the absorber layer for high ef?ciency photovoltaic solar cells.

  14. Hydrological and Geochemical Investigations of Selenium Behavior at Kesterson Reservoir

    E-Print Network [OSTI]

    Zawislanski, P.T.

    2010-01-01T23:59:59.000Z

    Ecological Characterization of Kesterson Reservoir. AnnualEcological Characterization of Kesterson Reservoir. Annual

  15. Hydrological and Geochemical Investigations of Selenium Behavior at Kesterson Reservoir

    E-Print Network [OSTI]

    Zawislanski, P.T.

    2010-01-01T23:59:59.000Z

    Cambridge. Cutter, G.A. , and K.W. Bruland. 1984. The marinesediments (Cutter and Bruland, 1984; Weres et al. , 1989a).

  16. Development of a small selenium barrier layer photovoltaic cell 

    E-Print Network [OSTI]

    Pruett, George Richard

    1954-01-01T23:59:59.000Z

    +lkt Rfl&t4 ~ + ~ ~ ~ s ~ s ~ o ~ ~ ~ I ~ ~ I PO4NNQ QLffOWOO 1ORWQO j1388$44@4El ~ ~ ~ o ~ o ~ RI04INRRRli 7OSIIS QXQ4%~ ~ 8 0 I ~ ~ ~ ~ 4 0 The ~oct af this Qaeestiguticu uus te develop a uotbcd by shish a osaXX selsakuu barbar Xsyer photovoltaic... cell night be undo sith a high degree uf reprccbccibility, This prost uus chosen because u ssoXX ooll could nct bo obtained frsn o~tuX firnoo snd these fiona guard the secrete of tho prcchetkoa of the photovoltaic ceXX very null Photovoltaic oa...

  17. amorphous selenium studied: Topics by E-print Network

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

    the potential energy landscape explored during a compression-decompression cycle for the SPCE (extended simple point charge) model of water. During the cycle, the system changes...

  18. Using Cytochrome c3 To Make Selenium A. Abdelouas,

    E-Print Network [OSTI]

    Shelnutt, John A.

    ´mica Fina e Biotecnologia, Departamento de Qui´mica, Faculdade de Cie^ncias e Tecnologia, Universidade Nova- tional Laboratories. | Departamento de Qui´mica, Faculdade de Cie^ncias e Tecnologia, Universidade Nova

  19. Selenium an Essential Micronutrient. Max Irsik DVM, MAB

    E-Print Network [OSTI]

    Watson, Craig A.

    of agricultural drainage water with sewage sludge or industrial activities such as fly ash from coal plants, oil with muscle lesions observed in lambs and calves at birth. This congenital type of white muscle disease may

  20. acute selenium toxicosis: Topics by E-print Network

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

    in rats Environmental Sciences and Ecology Websites Summary: Andrew J. Dalrymple and Bennett C. Calef, Jr. Department of Psychology McMaster University Hamilton, Ontario, Canada...

  1. Development of a small selenium barrier layer photovoltaic cell

    E-Print Network [OSTI]

    Pruett, George Richard

    1954-01-01T23:59:59.000Z

    +lkt Rfl&t4 ~ + ~ ~ ~ s ~ s ~ o ~ ~ ~ I ~ ~ I PO4NNQ QLffOWOO 1ORWQO j1388$44@4El ~ ~ ~ o ~ o ~ RI04INRRRli 7OSIIS QXQ4%~ ~ 8 0 I ~ ~ ~ ~ 4 0 The ~oct af this Qaeestiguticu uus te develop a uotbcd by shish a osaXX selsakuu barbar Xsyer photovoltaic... cell night be undo sith a high degree uf reprccbccibility, This prost uus chosen because u ssoXX ooll could nct bo obtained frsn o~tuX firnoo snd these fiona guard the secrete of tho prcchetkoa of the photovoltaic ceXX very null Photovoltaic oa...

  2. Hydrological and Geochemical Investigations of Selenium Behavior at Kesterson Reservoir

    E-Print Network [OSTI]

    Zawislanski, P.T.

    2010-01-01T23:59:59.000Z

    Gas-phase porosities varied between individual aggregates from 0.00 to 0.40, and were maintained relatively constant

  3. Hydrological and Geochemical Investigations of Selenium Behavior at Kesterson Reservoir

    E-Print Network [OSTI]

    Zawislanski, P.T.

    2010-01-01T23:59:59.000Z

    of Kesterson Reservoir, and supplements data provided in1991). The Reservoir-wide sampling data has been reviewed toinventory at Kesterson Reservoir. The data presented herein

  4. Near-surface electronic defects and morphology of CuIn1xGaxSe2 Y. M. Strzhemechnya)

    E-Print Network [OSTI]

    Rockett, Angus

    CIGS is a leading candidate for high-efficiency solar cells, yet the defects and electronic structure to the near-band-edge peak. Polycrystalline CdS/CIGS/Mo/glass and CIGS/Mo/glass solar-cell layers were also to measure the local band and defect properties of epitaxial CIGS films having 002 , 220 / 204 , or 112

  5. Curriculum Vitae 2011Present Ph.D. in Physics, Colorado State University, Fort Collins.

    E-Print Network [OSTI]

    Sites, James R.

    -PACE CIGS program, mainly focus on the device characterization and simulation of CIGS solar cells with Zn of CIGS solar cells with sputtered Zn(O,S) buffer layers (in progress) July 2013 Summer Intern, DOE-V Distortion of CIGS Solar Cells with Sputtered Zn(O,S) Buffer Layers Department of Physics, 1875 Campus

  6. Post-Deposition Treatment Boosts CIGS Solar Cell Performance (Fact Sheet), NREL Highlights in Research & Development, NREL (National Renewable Energy Laboratory)

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)IntegratedSpeeding accessPeptoidLabPhysicsPits |RegulationsPortableDOENREL's use

  7. (Data in kilograms of gallium content unless otherwise noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 2011. One company in Utah

    E-Print Network [OSTI]

    % was used in research and development, specialty alloys, and other applications. Optoelectronic devices were used in areas such as aerospace, consumer goods, industrial equipment, medical equipment

  8. (Data in kilograms of gallium content, unless otherwise noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 2001. Two companies in

    E-Print Network [OSTI]

    , specialty alloys, and other applications. Optoelectronic devices were used in areas such as consumer goods, medical equipment, industrial components, telecommunications, and aerospace applications. Integrated

  9. (Data in kilograms of gallium content, unless otherwise noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 2000. Two companies in

    E-Print Network [OSTI]

    and development, specialty alloys, and other applications. Optoelectronic devices were used in areas such as consumer goods, medical equipment, industrial components, telecommunications, and aerospace applications

  10. (Data in kilograms of gallium content, unless otherwise noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 2003. One company in

    E-Print Network [OSTI]

    , specialty alloys, and other applications. Optoelectronic devices were used in areas such as aerospace

  11. (Data in kilograms of gallium content unless otherwise noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 2006. One company in Utah

    E-Print Network [OSTI]

    , specialty alloys, and other applications. Optoelectronic devices were used in areas such as aerospace

  12. (Data in kilograms of gallium content unless otherwise noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 2010. One company in Utah

    E-Print Network [OSTI]

    and development, specialty alloys, and other applications. Optoelectronic devices were used in areas such as aerospace, consumer goods, industrial equipment, medical equipment, and telecommunications. ICs were used

  13. (Data in kilograms of gallium content unless otherwise noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 2007. One company in Utah

    E-Print Network [OSTI]

    and development, specialty alloys, and other applications. Optoelectronic devices were used in areas such as aerospace, consumer goods, industrial equipment, medical equipment, and telecommunications. ICs were used

  14. (Data in kilograms of gallium content unless otherwise noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 2004. One company in Utah

    E-Print Network [OSTI]

    % was used in research and development, specialty alloys, and other applications. Optoelectronic devices were used in areas such as aerospace, consumer goods, industrial equipment, medical equipment

  15. (Data in kilograms of gallium content unless otherwise noted) Domestic Production and Use: No domestic primary gallium recovery was reported in 2008. One company in Utah

    E-Print Network [OSTI]

    and development, specialty alloys, and other applications. Optoelectronic devices were used in areas such as aerospace, consumer goods, industrial equipment, medical equipment, and telecommunications. ICs were used

  16. Synthesis and characterization of visible emission from rare-earth doped aluminum nitride, gallium nitride and gallium aluminum nitride powders and thin films

    E-Print Network [OSTI]

    Tao, Jonathan Huai-Tse

    2010-01-01T23:59:59.000Z

    Converted White-Light-Emitting Diodes," Jap. J. Appl.doped III-N Light-Emitting Diodes," Appl. Phys. Lett. , 84 (in Packaging High Power Light Emitting Diode Arrays," Appl.

  17. Synthesis and characterization of visible emission from rare-earth doped aluminum nitride, gallium nitride and gallium aluminum nitride powders and thin films

    E-Print Network [OSTI]

    Tao, Jonathan Huai-Tse

    2010-01-01T23:59:59.000Z

    High-Color-Rendering LED Lamps Using Oxyfluoride andHigh-pressure mercury lamp LED Luxeon white 5 W LED Cree LRpressure mercury lamps; some Cree LEDs have even comparable

  18. Synthesis and characterization of visible emission from rare-earth doped aluminum nitride, gallium nitride and gallium aluminum nitride powders and thin films

    E-Print Network [OSTI]

    Tao, Jonathan Huai-Tse

    2010-01-01T23:59:59.000Z

    from GaN:Tb 3+ Powders and Thin Films Deposited by MOVPE andHirata, "Eu 3+ Activated GaN Thin Films Grown on Sapphire byTb 3+ in GaN Powders and Thin Films," ECS Trans. , J. Laski,

  19. Synthesis and characterization of visible emission from rare-earth doped aluminum nitride, gallium nitride and gallium aluminum nitride powders and thin films

    E-Print Network [OSTI]

    Tao, Jonathan Huai-Tse

    2010-01-01T23:59:59.000Z

    Growth of Single Crystal GaN Substrate using Hydride VaporZnO Nanowire on a p-GaN Substrate," J. Phys. Chem. C , 114Grown on GaN Nanocrystalline Powder Substrate," J. Cryst.

  20. LIFE CYCLE INVENTORY ANALYSIS IN THE PRODUCTION OF METALS USED IN PHOTOVOLTAICS.

    SciTech Connect (OSTI)

    FTHENAKIS,V.M.; KIM, H.C.; WANG, W.

    2007-03-30T23:59:59.000Z

    Material flows and emissions in all the stages of production of zinc, copper, aluminum, cadmium, indium, germanium, gallium, selenium, tellurium, and molybdenum were investigated. These metals are used selectively in the manufacture of solar cells, and emission and energy factors in their production are used in the Life Cycle Analysis (LCA) of photovoltaics. Significant changes have occurred in the production and associated emissions for these metals over the last 10 years, which are not described in the LCA databases. Furthermore, emission and energy factors for several of the by-products of the base metal production were lacking. This report aims in updating the life-cycle inventories associated with the production of the base metals (Zn, Cu, Al, Mo) and in defining the emission and energy allocations for the minor metals (Cd, In, Ge, Se, Te and Ga) used in photovoltaics.

  1. Epitaxial growth of Cu,,In,Ga...Se2 on GaAs,,110... and A. Rockett

    E-Print Network [OSTI]

    Rockett, Angus

    . INTRODUCTION The Cu(In, Ga)Se2 CIGS absorber layer in a recent record-efficiency CIGS solar cell1 has a 220.13 Commercially supplied ``epi-ready'' liquid- encapsulated Czo

  2. Selenium Accumulation, Distribution, and Speciation in Spineless Prickly Pear Cactus: A Drought- and Salt-Tolerant, Selenium-Enriched Nutraceutical Fruit Crop for Biofortified Foods

    E-Print Network [OSTI]

    Banuelos, Gary S.

    2012-01-01T23:59:59.000Z

    plants, in secondary accumulator plants, and in traceto that of secondary Se-accumulator plant species. Hence,found in second- ary accumulator Brassicaceae species grown

  3. Proc. of the 24th IEEE Photovoltaic Specialists Conference (IEEE, New York, 1995), pp. 164-167. SODIUM DIFFUSION, SELENIZATION, AND MICROSTRUCTURAL EFFECTS

    E-Print Network [OSTI]

    Scofield, John H.

    to our usual solar cell processing stages, including the high-temperature deposition of CIS and CIGS by the "best" polycrystalline thin film copper indium diselenide (CIGS) based small-area solar cells has risen their implications for CIS and CIGS solar cell fabrication. AS-DEPOSITED FILMS Sample Fabrication Films were sputter

  4. Presented at the 13th ICTMC, Oct 14 18, 2002

    E-Print Network [OSTI]

    Sites, James R.

    Abstract Solar cells have been fabricated with partial electrolyte treatments of CuInGaSe2 (CIGS) thin film efficient CIGS solar cells are fabricated in this manner, there are a few problems associated with the Cd by the completion of the solar cells with a ZnO layer. 2. Experimental Techniques CIGS thin films were grown at NREL

  5. In situ investigation of the selenization kinetics of CuGa precursors using time-resolved high-temperature X-ray diffraction

    E-Print Network [OSTI]

    Anderson, Timothy J.

    (CIGS) is a proven absorber material for high efficiency thin film solar cells with reported conversion- solar cell is the tandem cell structure that uses the high efficiency In-rich CIGS device as the bottom cell in a CIGS tandem solar cell structure [2­4]. Recently, a record-efficiency of 10.23% for a surface

  6. Determination of the minority carrier diffusion length in compositionally graded Cu,,In,Ga...Se2 solar cells using electron beam induced

    E-Print Network [OSTI]

    Wu, Junqiao

    .1063/1.3291046 Cu In,Ga Se2 CIGS solar cells have achieved efficien- cies above 19% using a compositionally graded,S 2 films.7­9 However, the best CIGS solar cells have a compo- sitionally graded profile.10 The graded in compositionally graded CIGS solar cells. Energy dependent EBIC measurements were collected in the planar

  7. Effect of Ga content on defect states in CuIn1xGaxSe2 photovoltaic devices

    E-Print Network [OSTI]

    Rockett, Angus

    gaps for single junction solar cells expected to be around 1.4 eV.2 This corresponds to a Ga fraction x gap of CuIn1 xGaxSe2 CIGS . This technique is sensitive to opti- cal absorption in the active layer CIGS. Photovoltaic devices based on thin polycrystalline CIGS absorbers have achieved record lab

  8. Toward microscale Cu,,In,Ga...Se2 solar cells for efficient conversion and optimized material usage: Theoretical evaluation

    E-Print Network [OSTI]

    Boyer, Edmond

    develop a model to predict the performances of microscale Cu In,Ga Se2 CIGS solar cells under concentrated limiting factor for concentration on CIGS solar cells. This model can be used to extract the value associated with the operation of microscale CIGS solar cells are studied. The optimum concentration ratio

  9. COMPARISON OF TRAP STATES BETWEEN CIGSS/CdS/ZnO AND Cd PE CIGSS/ZnO CELLS P.K. Johnson, A.O. Pudov, J.R. Sites

    E-Print Network [OSTI]

    Sites, James R.

    (CIGS) thin films were treated in Cd solutions (Cd PE treatment) yielded solar cells with efficiencies surface can produce a cell comparable to the best CdS/CIGS cells. We extend this work to include CIGSS Defects - 3 1. INTRODUCTION Polycrystalline CIGS thin film photovoltaic cells are known for their high

  10. This content has been downloaded from IOPscience. Please scroll down to see the full text. Download details

    E-Print Network [OSTI]

    Napp, Nils

    absorbers. In this study, the effects of a graded bandgap profile on the cell performance of a CIGS solar The Japan Society of Applied Physics 1. Introduction Cu(In,Ga)Se2 (CIGS) solar cells have demonstrated a high conversion efficiency of over 20%.1) Also, the CIGS solar cells have many advantages

  11. Int'l PVSEC -121 Technical Digest of the International PVSEC-14, Bangkok, Thailand, 2004

    E-Print Network [OSTI]

    Romeo, Alessandro

    Properties of CIGS solar cells developed with evaporated II-VI buffer layers A. Romeo, R. Gysel, S. Buzzi, D in Voc and FF are measured. 1. Introduction High efficiency CIGS solar cells have been obtained. We present a comparison of the CIGS based solar cells made with CBD, PVD-CdS and PVD-Zn-based buffer

  12. Simulation of Polycrystalline Cu(In,Ga)Se2 Solar Cells in Two Dimensions Markus Gloeckler, Wyatt K. Metzger1

    E-Print Network [OSTI]

    Sites, James R.

    10%­12% [2]. This work uses numerical simulations to predict the changes to CIGS solar-cell an electrostatic potential, which has been reported in the literature for CIGS solar cells [3­5]. A valence that a plausible reason behind highly efficient thin-film CIGS solar cells ( > 17%) is an inherent valence

  13. Silicon Oxynitride Thin Film Barriers for PV Packaging (Poster)

    SciTech Connect (OSTI)

    del Cueto, J. A.; Glick, S. H.; Terwilliger, K. M.; Jorgensen, G. J.; Pankow, J. W.; Keyes, B. M.; Gedvilas, L. M.; Pern, F. J.

    2006-10-03T23:59:59.000Z

    Dielectric, adhesion-promoting, moisture barriers comprised of silicon oxynitride thin film materials (SiOxNy with various material stoichiometric compositions x,y) were applied to: 1) bare and pre-coated soda-lime silicate glass (coated with transparent conductive oxide SnO2:F and/or aluminum), and polymer substrates (polyethylene terephthalate, PET, or polyethylene napthalate, PEN); plus 2) pre- deposited photovoltaic (PV) cells and mini-modules consisting of amorphous silicon (a-Si) and copper indium gallium diselenide (CIGS) thin-film PV technologies. We used plasma enhanced chemical vapor deposition (PECVD) process with dilute silane, nitrogen, and nitrous oxide/oxygen gas mixtures in a low-power (< or = 10 milliW per cm2) RF discharge at ~ 0.2 Torr pressure, and low substrate temperatures < or = 100(degrees)C, over deposition areas ~ 1000 cm2. Barrier properties of the resulting PV cells and coated-glass packaging structures were studied with subsequent stressing in damp-heat exposure at 85(degrees)C/85% RH. Preliminary results on PV cells and coated glass indicate the palpable benefits of the barriers in mitigating moisture intrusion and degradation of the underlying structures using SiOxNy coatings with thicknesses in the range of 100-200 nm.

  14. Gallium surface diffusion on GaAs (001) surfaces measured by crystallization dynamics of Ga droplets

    SciTech Connect (OSTI)

    Bietti, Sergio, E-mail: sergio.bietti@mater.unimib.it; Somaschini, Claudio; Esposito, Luca; Sanguinetti, Stefano [L–NESS and Dipartimento di Scienza dei Materiali, Universitŕ di Milano Bicocca, Via Cozzi 55, I–20125 Milano (Italy); Fedorov, Alexey [L–NESS and CNR–IFN, via Anzani 42, I-22100 Como (Italy)

    2014-09-21T23:59:59.000Z

    We present accurate measurements of Ga cation surface diffusion on GaAs surfaces. The measurement method relies on atomic force microscopy measurement of the morphology of nano–disks that evolve, under group V supply, from nanoscale group III droplets, earlier deposited on the substrate surface. The dependence of the radius of such nano-droplets on crystallization conditions gives direct access to Ga diffusion length. We found an activation energy for Ga on GaAs(001) diffusion E{sub A}=1.31±0.15 eV, a diffusivity prefactor of D{sub 0}?=?0.53(×2.1±1) cm{sup 2} s{sup ?1} that we compare with the values present in literature. The obtained results permit to better understand the fundamental physics governing the motion of group III ad–atoms on III–V crystal surfaces and the fabrication of designable nanostructures.

  15. Fabrication of an optically driven 10 GHz ring resonator on a gallium arsenide substrate

    E-Print Network [OSTI]

    McGregor, Douglas Scott

    1989-01-01T23:59:59.000Z

    /D converters, optical detectors, dc to rf converters, and millimeter-wave or microwave generators. Photoconductors can be easily integrated with microelectronic devices as well as microwave circuits. Recently, an optically excited photoconductive switch... is the barrier height and y, is the electron affinity for the semiconductor. Current flow at a metal-semiconductor barrier is due mainly to majority carriers. The four major current transport methods are thermionic emission over the barrier, quantum...

  16. Synthesis, characterization, and biotemplated assembly of indium nitride and indium gallium nitride nanoparticles

    E-Print Network [OSTI]

    Hsieh, Jennifer Chia-Jen

    2010-01-01T23:59:59.000Z

    A low-temperature, ambient pressure solution synthesis of colloidal InN nanoparticles is presented. This synthesis utilizes a previously dismissed precursor and results in individual, non-aggregated nanoparticles with ...

  17. Non-Destructive Spent Fuel Characterization with Semi-Conducting Gallium Arsinde Neutron Imaging Arrays

    SciTech Connect (OSTI)

    Douglas S. McGregor; Holly K. Gersch; Jeffrey D. Sanders; John C. Lee; Mark D. Hammig; Michael R. Hartman; Yong Hong Yang; Raymond T. Klann; Brian Van Der Elzen; John T. Lindsay; Philip A. Simpson

    2002-01-30T23:59:59.000Z

    High resistivity bulk grown GaAs has been used to produce thermal neutron imaging devices for use in neutron radiography and characterizing burnup in spent fuel. The basic scheme utilizes a portable Sb/Be source for monoenergetic (24 keV) neutron radiation source coupled to an Fe filter with a radiation hard B-coated pixellated GaAs detector array as the primary neutron detector. The coated neutron detectors have been tested for efficiency and radiation hardness in order to determine their fitness for the harsh environments imposed by spent fuel. Theoretical and experimental results are presented, showing detector radiation hardness, expected detection efficiency and the spatial resolution from such a scheme. A variety of advanced neutron detector designs have been explored, with experimental results achieving 13% thermal neutron detection efficiency while projecting the possibility of over 30% thermal neutron detection efficiency.

  18. Radiolabeled porphyrin versus gallium-67 citrate for the detection of human melanoma in athymic mice

    SciTech Connect (OSTI)

    Maric, N.; Chan, S. Ming; Hoffer, P.B.; Duray, P.

    1987-01-01T23:59:59.000Z

    We performed the biodistribution and imaging studies of /sup 111/In and /sup 67/Ga labeled tetra(4-N-methylpyridyl) porphine, (T4NMPYP), and compared it to that of /sup 67/Ga citrate in athymic mice bearing a human melanoma xenograft. The biodistribution results of both /sup 111/In and /sup 67/Ga labeled T4NMPYP (3, 6, 24, and 48 hours) were similar but differed from that of /sup 67/Ga citrate (48 hours). The optimum tumor uptake of both radiolabeled porphyrins was at 6 hours postinjection and was lower than the tumor uptake of /sup 67/Ga citrate at 48 hours postinjection. Kidney was the only organ showing higher uptake of radiolabeled porphyrin compared to that of /sup 67/Ga citrate. The imaging studies performed with /sup 111/In T4NMPYP and /sup 67/Ga citrate correspond to the biodistribution results. Osteomyelitis present in one mouse showed good localization of /sup 111/In T4NMPYP. 15 refs., 3 figs., 5 tabs.

  19. Electrical properties of atomic layer deposited aluminum oxide on gallium nitride

    SciTech Connect (OSTI)

    Esposto, Michele; Krishnamoorthy, Sriram; Nath, Digbijoy N.; Bajaj, Sanyam; Hung, Ting-Hsiang; Rajan, Siddharth

    2011-09-26T23:59:59.000Z

    We report on our investigation of the electrical properties of metal/Al{sub 2}O{sub 3}/GaN metal-insulator-semiconductor capacitors. We determined the conduction band offset and interface charge density of the alumina/GaN interface by analyzing the capacitance-voltage characteristics of atomic layer deposited Al{sub 2}O{sub 3} films on GaN substrates. The conduction band offset at the Al{sub 2}O{sub 3}/GaN interface was calculated to be 2.13 eV, in agreement with theoretical predications. A non-zero field of 0.93 MV/cm in the oxide under flat-band conditions in the GaN was inferred, which we attribute to a fixed net positive charge density of magnitude 4.60 x 10{sup 12 }cm{sup -2} at the Al{sub 2}O{sub 3}/GaN interface. We provide hypotheses to explain the origin of this charge by analyzing the energy band line-up.

  20. Sparse gallium arsenide to silicon metal waferbonding for heterogeneous monolithic microwave integrated circuits

    E-Print Network [OSTI]

    Bickford, Justin Robert

    2008-01-01T23:59:59.000Z

    is limited by the cold-wall chamber design and the porousrepeatability. The cold-wall chamber design also limits the

  1. Commercialization of gallium nitride nanorod arrays on silicon for solid-state lighting

    E-Print Network [OSTI]

    Wee, Qixun

    2008-01-01T23:59:59.000Z

    One important component in energy usage is lighting, which is currently dominated by incandescent and fluorescent lamps. However, due to potentially higher efficiencies and thus higher energy savings, solid-state lighting ...

  2. The equilibrium state of hydrogen in gallium nitride: Theory and experiment

    SciTech Connect (OSTI)

    MYERS JR.,SAMUEL M.; WRIGHT,ALAN F.; PETERSEN,GARY A.; SEAGER,CARLETON H.; WAMPLER,WILLIAM R.; CRAWFORD,MARY H.; HAN,JUNG

    2000-04-17T23:59:59.000Z

    Formation energies and vibrational frequencies for H in wurtzite GaN were calculated from density functional theory and used to predict equilibrium state occupancies and solid solubilities for p-type, intrinsic, and n-type material. The solubility of deuterium (D) was measured at 600--800 C as a function of D{sub 2} pressure and doping and compared with theory. Agreement was obtained by reducing the H formation energies 0.2 eV from ab-initio theoretical values. The predicted stretch-mode frequency for H bound to the Mg acceptor lies 5% above an observed infrared absorption attributed to this complex. It is concluded that currently recognized H states and physical processes account for the equilibrium behavior of H examined in this work.

  3. Diffusion, Uptake and Release of Hydrogen in p-type Gallium Nitride: Theory and Experiment

    SciTech Connect (OSTI)

    MYERS JR.,SAMUEL M.; WRIGHT,ALAN F.; PETERSEN,GARY A.; WAMPLER,WILLIAM R.; SEAGER,CARLETON H.; CRAWFORD,MARY H.; HAN,JUNG

    2000-06-27T23:59:59.000Z

    The diffusion, uptake, and release of H in p-type GaN are modeled employing state energies from density-function theory and compared with measurements of deuterium uptake and release using nuclear-reaction analysis. Good semiquantitative agreement is found when account is taken of a surface permeation barrier.

  4. Sparse gallium arsenide to silicon metal waferbonding for heterogeneous monolithic microwave integrated circuits

    E-Print Network [OSTI]

    Bickford, Justin Robert

    2008-01-01T23:59:59.000Z

    and Applications, edited by T. M. Tritt, ( Kluwer Academic /and Applications, edited by T. M. Tritt, ( Kluwer Academic /and Applications, edited by T. M. Tritt, ( Kluwer Academic /

  5. SAGE: Solar Neutrino Data from SAGE, the Russian-American Gallium Solar Neutrino Experiment

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    SAGE Collaboration

    SAGE is a solar neutrino experiment based on the reaction 71Ga + n goes to 71Ge + e-. The 71Ge atoms are chemically extracted from a 50-metric ton target of Ga metal and concentrated in a sample of germane gas mixed with xenon. The atoms are then individually counted by observing their decay back to 71Ga in a small proportional counter. The distinguishing feature of the experiment is its ability to detect the low-energy neutrinos from proton-proton fusion. These neutrinos, which are made in the primary reaction that provides the Sun's energy, are the major component of the solar neutrino flux and have not been observed in any other way. To shield the experiment from cosmic rays, it is located deep underground in a specially built facility at the Baksan Neutrino Observatory in the northern Caucasus mountains of Russia. Nearly 100 measurements of the solar neutrino flux have been made during 1990-2000, and their combined result is a neutrino capture rate that is well below the prediction of the Standard Solar Model. The significant suppression of the solar neutrino flux that SAGE and other solar neutrino experiments have observed gives a strong indication for the existence of neutrino oscillations. [copied from the SAGE homepage at http://ewi.npl.washington.edu/SAGE/SAGE.html

  6. Synthesis and optical properties of CsC1-doped gallium-sodium-sulfide glasses

    SciTech Connect (OSTI)

    Hehlen, Markus P [Los Alamos National Laboratory; Bennett, Bryan L [Los Alamos National Laboratory; Williams, Darrick J [Los Alamos National Laboratory; Muenchausen, Ross E [Los Alamos National Laboratory; Castro, Alonso [Los Alamos National Laboratory; Tornga, Stephanie C [Los Alamos National Laboratory

    2009-01-01T23:59:59.000Z

    Ga{sub 2}S{sub 3}-Na{sub 2}S (GNS) glasses doped with CsCl were synthesized in open crucibles under inert atmosphere. The evaporative loss of CsCl during glass melting was measured by energy dispersive X-ray spectroscopy and corrected for by biasing the CsCl concentration in the mixture of starting materials to obtain glasses with accurately controlled stoichiometry. Glass transition temperatures, refractive index dispersions, and band edge energies were measured for four GNS:CsCl glasses, and the respective values were found to significantly improve over earlier studies that did not mitigate CsCl evaporative losses. The refractive index dispersion measurements indicate that the Cs{sup +} and Cl{sup -} radii are 16% larger in GNS:CsCl glass than in bulk crystalline CsCl. The band edge energy increases from 2.97 eV in GNS glass to 3.32 eV in GNS glass doped with 20 mol% CsCl as a result of introducing Cl{sup -} ions having a large optical electronegativity. The large bandgap of 3.32 eV and the low (450 cm{sup -1}) phonon energy make GNS:20%CsCl an attractive host material for rare-earth ions with radiative transitions in the near ultra-violet, visible, and near-infrared spectral regions.

  7. The marine geochemistry of dissolved gallium: A comparison with dissolved aluminum

    SciTech Connect (OSTI)

    Orians, K.J.; Bruland, K.W. (Univ. of California, Santa Cruz (USA))

    1988-12-01T23:59:59.000Z

    Dissolved Ga concentrations in the pacific Ocean range from 2 to 30 picomolar: they are low in surface waters (2-12 pM), with a subsurface maximum at 150-300 m (6-17 pM), a mid-depth minimum from 500 to 1,000 m (4-10 pM) and increasing values with depth to a maximum in the bottom waters (12-30 pM). The highest concentrations are in the central gyre, with lower values toward the north and east where productivity and particle scavenging increase. Dissolved Ga concentrations in the surface waters of the northwest Atlantic are nearly an order of magnitude higher than in the central North pacific, with higher values in the Gulf Stream than in the continental slope boundary region. The vertical distributions and horizontal transects indicate three sources of dissolved Ga to the oceans. The surface distribution reflects an eolian source with no net fluvial input to the open ocean; the subsurface maximum (a feature not seen for North Pacific dissolved Al) is attributed to vertical exchange processes; the source for the deep waters of the North Pacific is from a sediment surface remineralization process or a pore water flux. Scavenging removal throughout the water column is evident in the vertical profiles for both dissolved Ga and Al, with intensified removal in the boundary regions where productivity and particle scavenging are at a maximum. Residence times of dissolved Ga in surface waters are nearly an order of magnitude longer than the corresponding values for Al.

  8. Sparse gallium arsenide to silicon metal waferbonding for heterogeneous monolithic microwave integrated circuits

    E-Print Network [OSTI]

    Bickford, Justin Robert

    2008-01-01T23:59:59.000Z

    process: after sample pair wax wetting. .. 311 Figureprocess: after PMGI and wax dissolution and composite1. Picture of an example wax wetting two microscope slide

  9. Tungsten-incorporation induced red-shift in the bandgap of gallium oxide thin films

    SciTech Connect (OSTI)

    Rubio, E. J.; Ramana, C. V. [Department of Mechanical Engineering, University of Texas at El Paso, El Paso, Texas 79968 (United States)] [Department of Mechanical Engineering, University of Texas at El Paso, El Paso, Texas 79968 (United States)

    2013-05-13T23:59:59.000Z

    Tungsten (W) incorporated Ga{sub 2}O{sub 3} films were produced by co-sputter deposition. W-concentration was varied by the applied sputtering-power. The structure and optical properties of W-incorporated Ga{sub 2}O{sub 3} films were evaluated using X-ray diffraction, scanning electron microscopy, and spectrophotometric measurements. No secondary phase formation was observed in W-incorporated Ga{sub 2}O{sub 3} films. W-induced effects were significant on the structure and optical properties of Ga{sub 2}O{sub 3} films. The bandgap of Ga{sub 2}O{sub 3} films without W-incorporation was {approx}5 eV. Red-shift in the bandgap was noted with increasing W-concentration indicating the electronic structure changes in W-Ga{sub 2}O{sub 3} films. A functional relationship between W-concentration and optical property is discussed.

  10. Sparse gallium arsenide to silicon metal waferbonding for heterogeneous monolithic microwave integrated circuits

    E-Print Network [OSTI]

    Bickford, Justin Robert

    2008-01-01T23:59:59.000Z

    4240 OUTPUT 708;"B12X" ! turns TEG-1 bubbler off 4250 OUTPUT708;"B8X" ! turns TEG-2,3 bubbler off 4260 OUTPUT 708;"OUTPUT 709;"B11X" ! turns TEG-1 out off OUTPUT 709;"B7X" !

  11. The determination of titanium, germanium and gallium by charged particle activation analysis

    E-Print Network [OSTI]

    Novak, Leo Robert

    1975-01-01T23:59:59.000Z

    . 3 hz 0. 559 3. 008 -13. 540 5. 143 2. 859 -11. 529 9. 0 x 10 5 1. 10 x 10 5 9. 31 x 10 5 1. 35 x 10 5 1. 17 x 10 5 70 69 Ge (p, pn) Ge 74 11 se(p, o) As 76 72 Se(p, an) As -11. 529 ' 0. 545 10. 245 a) dps per NA for 1 minute.... 85 x 10 74 Se(d, nn) As 71 1. 680 Ge(6, 2n) As 72 26. 0 hr . 834 7. 367 2. 86 x 10 746 (0 ) 72A 6. 718 "Ge(d. n) ' As Ge (d, 2n) As 17. 76 d . 596 6. 176 - 5. 570 2. 72 x 10 As(d, dn) As -10. 248 a) dps per VA for 1 minute irradietions, natural...

  12. The Hall mobility measurement of Liquid Phase Epitaxy grown aluminum gallium arsenide

    E-Print Network [OSTI]

    Choi, Young-Shig

    1986-01-01T23:59:59.000Z

    -type AJGaAs mobility as a function of doping concentration with temperature as a, parameter. . 51 CHAPTER I INTRODUCTION AI?Ga& ?As (x is the mole fraction of Al) has been employed to fabricate discrete Light Emitting Diodes (LED) and Laser Diodes... grown l&y 1. PE are the lasers and light, -emitting diodes, 2, 31. 10 One limitation of the LPE technique is the difficulty of growing layers that differ in lattice constant by more than lv/& from the substrate. Lattice mismatch, occuring whenever...

  13. Electrical properties of TiN on gallium nitride grown using different deposition conditions and annealing

    SciTech Connect (OSTI)

    Li, Liuan; Kishi, Akinori; Shiraishi, Takayuki; Jiang, Ying; Wang, Qingpeng; Ao, Jin-Ping, E-mail: jpao@ee.tokushima-u.ac.jp [Institute of Technology and Science, The University of Tokushima, Tokushima 770-8506 (Japan)

    2014-03-15T23:59:59.000Z

    This study evaluates the thermal stability of different refractory metal nitrides used as Schottky electrodes on GaN. The results demonstrate that TiN, MoSiN, and MoN possess good rectification and adhesion strength, with barrier heights of 0.56, 0.54, and 0.36?eV, respectively. After thermal treatment at 850?°C for 1?min, the TiN and MoN electrodes still exhibit rectifying characteristics, while the MoSiN degrades to an ohmic-like contact. For further study, several TiN films are deposited using different N{sub 2}/Ar reactive/inert sputtering gas ratios, thereby varying the nitrogen content present in the sputtering gas. Ohmic-like contact is observed with the pure Ti contact film, and Schottky characteristics are observed with the samples possessing nitrogen in the film. The average Schottky barrier height is about 0.5?eV and remains virtually constant with varying nitrogen deposition content. After examining Raman spectra and x-ray photoelectron spectroscopy results, the increase in the film resistivity after thermal treatment is attributed to oxidation and/or nitridation. Films deposited with a medium (40% and 60%) nitrogen content show the best film quality and thermal stability.

  14. Gallium-68 Bioorthogonal Tetrazine Polymers for the Multistep Labeling of Cancer Biomarkers /

    E-Print Network [OSTI]

    Nichols, Brandon Edward

    2013-01-01T23:59:59.000Z

    68 somatostatin receptor PET/CT: is it time to replace (111)mapping of the prostate using PET/CT fusion imaging and Ga-

  15. Nanoheteroepitaxy of gallium arsenide on strain-compliant silicon-germanium nanowires

    SciTech Connect (OSTI)

    Chin, Hock-Chun; Gong, Xiao; Yeo, Yee-Chia [Department of Electrical and Computer Engineering, National University of Singapore (NUS), Singapore 117576 (Singapore); Ng, Tien Khee; Loke, Wan Khai; Wicaksono, Satrio; Yoon, Soon Fatt [School of Electrical and Electronic Engineering, Nanyang Technological University (NTU), Nanyang Avenue, Singapore 639798 (Singapore); Wong, Choun Pei; Shen, Zexiang [Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University (NTU), Singapore 637371 (Singapore)

    2010-07-15T23:59:59.000Z

    Heterogeneous integration of high-quality GaAs on Si-based substrates using a selective migration-enhanced epitaxy (MEE) of GaAs on strain-compliant SiGe nanowires was demonstrated for the first time. The physics of compliance in nanoscale heterostructures was captured and studied using finite-element simulation. It is shown that nanostructures can provide additional substrate compliance for strain relief and therefore contribute to the formation of defect-free GaAs on SiGe. Extensive characterization using scanning electron microscopy and cross-sectional transmission electron microscopy was performed to illustrate the successful growth of GaAs on SiGe nanowire. Raman and Auger electron spectroscopy measurements further confirmed the quality of the GaAs grown and the high growth selectivity of the MEE process.

  16. Sparse gallium arsenide to silicon metal waferbonding for heterogeneous monolithic microwave integrated circuits

    E-Print Network [OSTI]

    Bickford, Justin Robert

    2008-01-01T23:59:59.000Z

    lasers utilizing an InGaP etch-stop layer,” Semiconductor1992). Cirtic acid GaAs from InGaP: D. Arslan, A. Dehé, and1999). Hydrochloric acid InGaP from GaAs: J. R. Lothian, J.

  17. amorphous indium-gallium-zinc oxide: Topics by E-print Network

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

    Summary: alloy of composition correspond- ing to the metallic components of the superconduct- ing oxides respectivement. Abstract. - Previous quenching experiments on 2212...

  18. Radiation-Hardened Gallium Nitride Detector and Arrays for Fusion Diagnostics

    SciTech Connect (OSTI)

    Sun, K. X., and MacNeil, L.

    2011-09-08T23:59:59.000Z

    This poster reports testing to confirm that GaN devices exhibit the extreme radiation hardness needed for use at the NIF, functioning properly after 1x10{sup 12} protons/cm{sup 2} proton irradiation in one year.

  19. X-ray photoelectron spectroscopy of gallium nitride films grown by radical-beam gettering epitaxy

    SciTech Connect (OSTI)

    Rogozin, I. V. [Berdyansk State Pedagogical University (Ukraine)], E-mail: rogozin@bdpu.org; Kotlyarevsky, M. B. [Academy of Management and Information Technology (Ukraine)

    2007-05-15T23:59:59.000Z

    Thin GaN films were grown on GaAs(111) substrates by radical-beam gettering epitaxy. The structural quality of the films was studied by high-resolution x-ray diffraction. The chemical composition of the GaAs surface and GaN film was studied by x-ray photoelectron spectroscopy. It is shown that Ga-N and As-N bonds are formed on the GaAs surface at initial growth stages at low temperatures. The state of the film-substrate interface was studied. It was found that prolonged annealing of GaN films in nitrogen radicals shifts the composition to nitrogen excess.

  20. Fabrication of optoelectronic microwave linear and ring resonators on a gallium arsenide substrate 

    E-Print Network [OSTI]

    Yeh, Chun-Liang

    1993-01-01T23:59:59.000Z

    the frequency ~, = urn' +amoco) have been observed. In the third part of the optical tests, the degenerate parametric amplification of an optical signal RF modulated at the first mode of the resonator with a microwave pumping LO at second mode... for the ring resonator. 77 46 Mixing Test Setup. 79 47 The sum signal IF, for the linear resonator with 10 prn coupling gap. The RF signal is at 4. 875 GHz and the I, O signal is at 4. 750 GHz, where the IF, signal (users = ans + uiqo) is detected at 9. 624...

  1. Gallium Arsenide-Based Readout Electronics Thomas J. Cunningham and Eric R. Fossum

    E-Print Network [OSTI]

    Fossum, Eric R.

    susceptible to radiation and hot carrier damage than are MaS-based structures. This should result in increased;among these has been the construction of optical emitters such as LEDs and lasers, since efficient

  2. Gallium arsenide-based ternary compounds and multi-band-gap solar cell research

    SciTech Connect (OSTI)

    Vernon, S. (Spire Corp., Bedford, MA (United States))

    1993-02-01T23:59:59.000Z

    Aim of this contract is the achievement of a high-efficiency, low-cost solar cell. The basic approach to the problem is centered upon the heteroepitaxial growth of a III-V compound material onto a single-crystal silicon wafer. The growth technique employed is metalorganic chemical vapor deposition. The silicon wafer may serve as a mechanical substrate and ohmic contact for a single-junction device, or may contain a p-n junction of its own and form the bottom cell of a two junction tandem solar cell structure. The III-V material for the single-junction case is GaAs and for the two-junction case is either GaAlAs or GaAsP, either material having the proper composition to yield a band gap of approximately 1.7 eV. Results achieved in this contract include the following: (1) a 17.6% efficient GaAs-on-Si solar cell; (2) an 18.5% efficient GaAs-on-Si concentrator solar cell at 400 suns; (3) a 24.8% efficient GaAs-on-GaAs solar cell; (4) a 28.7% efficient GaAs-on-GaAs concentrator solar cell at 200 suns; (5) measurement of the effects of dislocation density and emitter doping on GaAs cells; and (6) improvements in the growth process to achieve reproducible thin AlGaAs window layers with low recombination velocities and environmental stability.

  3. Sparse gallium arsenide to silicon metal waferbonding for heterogeneous monolithic microwave integrated circuits

    E-Print Network [OSTI]

    Bickford, Justin Robert

    2008-01-01T23:59:59.000Z

    affect the Ni heater photolithography step, but with properstep impulse current is driven through a monolithic heater

  4. High Quality, Low Cost Bulk Gallium Nitride Substrates Grown by the Electrochemical Solution Growth Method

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742Energy ChinaofSchaefer To:Department of EnergySeacrist, Senior Fellow - Emerging Technologies

  5. High-Quality, Low-Cost Bulk Gallium Nitride Substrates | Department of

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742Energy ChinaofSchaefer To:Department of EnergySeacrist, SeniorVolume 6 Building

  6. Sandia Energy - BES Web Highlight: Single-mode gallium nitride nanowire

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's PossibleRadiation Protection245C Unlimited ReleaseWelcome ton6Andy

  7. Gallium Safety in the Laboratory INEEL/CON-03-00078

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItem Not Found Item Not Found The itemAIR57451DOE/SC0002390dV DOE/m/10412 - 6 PROGWM:This

  8. The oxidative addition of simple selenium molecules to an unsaturated iridium (I) compound 

    E-Print Network [OSTI]

    Hsieh, Mel-Lin Mary

    1970-01-01T23:59:59.000Z

    . It was used without further purification. Triphenylphosphine, practical grade, was purchased from 11 the Metal and Thermit Corp. and was used following recrystallisa- tion from hot 95? alcohol. Aluminum, U. S. P. powder, was purchased from...

  9. Higher whole-blood selenium is associated with improved immune responses in footrot-affected sheep

    E-Print Network [OSTI]

    2011-01-01T23:59:59.000Z

    R: Footrot Eradication in Western Australia Published by theof Agriculture Western Australia, Scott Print; 2003. 7.FR in flocks in Western Australia [6], this protocol is

  10. Enhanced luminescence in Er3+ -doped chalcogenide glass-ceramics based on selenium

    E-Print Network [OSTI]

    Boyer, Edmond

    *laurent.calvez@univ-rennes1.fr Tel: (33) 2 23 23 67 13 Fax: (33) 2 23 23 56 11 b Arizona Materials. These materials are promising candidates for the production of new laser sources in the mid-infrared region of chalcogenide glasses presents two major advantages for the production of laser materials operating

  11. Selenium hyperaccumulation offers protection from cell disruptor herbivores Colin F. Quinn1,#

    E-Print Network [OSTI]

    author Author email addresses: CFQ: cquinn@lamar.colostate.edu JLF: jlfreema@lamar.colostate.edu RJBR: epsmits@lamar.colostate.edu #12;2 ABSTRACT Background Hyperaccumulation, the rare capacity of certain

  12. Selenium Accumulation in Brassicaceae Plant Species and its Biotransfer to Insect Pollinators

    E-Print Network [OSTI]

    Hladun, Kristen

    2012-01-01T23:59:59.000Z

    a cost to accumulating Se in secondary accumulator plants.In secondary accumulator plants, selenate can be reduced toelements found in non-accumulator plants (Brown and Shrift

  13. Novel fabrication and enhanced photosensitivity of selenium filament arrays by optical-fiber thermal drawing

    E-Print Network [OSTI]

    Deng, D. S.

    We report break-up of cylindrical shell into well-ordered filament arrays by optical-fiber thermal drawing. Enhanced photosensitivity of centimeter-long crystalline-Se nano-filaments is observed and the mechanism is ...

  14. Selenium Hyperaccumulator Plants Stanleya pinnata and Astragalus bisulcatus Are Colonized by Se-Resistant, Se-

    E-Print Network [OSTI]

    .pone.0050516 Editor: Martin Heil, Centro de Investigacio´n y de Estudios Avanzados, Mexico Received May 16 #IOS-0817748 to EAHP. The Advanced Light Source is supported by the Office of Science, Basic Energy

  15. Selenium Accumulation in Brassicaceae Plant Species and its Biotransfer to Insect Pollinators

    E-Print Network [OSTI]

    Hladun, Kristen

    2012-01-01T23:59:59.000Z

    an important strategy for land reclamation (Pilon-Smits anda potential strategy for land reclamation (Pilon-Smits and

  16. Selenium Accumulation in Brassicaceae Plant Species and its Biotransfer to Insect Pollinators

    E-Print Network [OSTI]

    Hladun, Kristen

    2012-01-01T23:59:59.000Z

    ecology in radish (Raphanus sativus L. )…………………………………….95et al. 2011) and Raphanus sativus L. (radish) (Hladun,in enriched radish (Raphanus sativus): A potential dietary

  17. Molecular Mechanisms of Selenium Tolerance and Hyperaccumulation in Stanleya pinnata1[W][OA

    E-Print Network [OSTI]

    scans mainly detected a carbon-Se-carbon compound (presumably selenocystathionine) in addition to some. pinnata. The species also showed different leaf Se sequestration patterns: while S. albescens showed-regulating sulfur/Se assimilation followed by methylation of selenocysteine and the targeted sequestration

  18. Micro-spectroscopic investigation of selenium-bearing minerals from the Western US Phosphate Resource Area

    E-Print Network [OSTI]

    , and are not con- sidered to be mobile or bioavailable.6 Selenite (SeO3 2 ) and selenate (SeO4 2 ) are more soluble

  19. Sorption of Arsenic, Mercury, Selenium onto Nanostructured Adsorbent Media and Stabilization via Surface Reactions

    E-Print Network [OSTI]

    Han, Dong Suk

    2011-02-22T23:59:59.000Z

    as pH increased. In addition, a surface complexation model (SCM) based on the diffuse layer model (DLM) was used to predict arsenic adsorption envelopes by NTAs under various environmental conditions. The SCM for As(III, V) adsorption by NTAs...

  20. Effects of selenium hyperaccumulation on plantplant interactions: evidence for elemental allelopathy?

    E-Print Network [OSTI]

    of S by Se in proteins (Stadtman, 1990). Bioavailable Se in soil occurs primarily in the form of selenate (Se concentrations of > 10 mg kg)1 (Zhu et al., 2009). Despite their apparent lack of a physio- logical requirement

  1. amorphous selenium flat-panel: Topics by E-print Network

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

    and organic Heikenfeld, Jason 12 Asymmetric electrical properties of fork a-Si:H thin-film transistor and its application to flat panel displays Mathematics Websites Summary:...

  2. Selenium Partitioning and Food-Chain Transfer at the Salton Sea

    E-Print Network [OSTI]

    Tobin, Jennifer Marie

    2011-01-01T23:59:59.000Z

    into labeled Nalgene plastic bottles filled with deionized (and stored in plastic bottles or branches containingacid- washed Nalgene plastic bottles. Vertical zooplankton

  3. Selenium Accumulation in Brassicaceae Plant Species and its Biotransfer to Insect Pollinators

    E-Print Network [OSTI]

    Hladun, Kristen

    2012-01-01T23:59:59.000Z

    farm drainage systems such as constructed solar andon- farm drainage management systems such as solar or

  4. Removal of Selenium from Wastewater using ZVI and Hybrid ZVI/Iron Oxide Process

    E-Print Network [OSTI]

    Yang, Zhen

    2012-12-20T23:59:59.000Z

    . The hZVI system process is a novel chemical treatment that has shown valuable potential for removing several heavy metals from wastewater. This study concluded that at bench scale, the removal efficiency of SeCN- in the wastewater is over 99% with 2...

  5. Removal of Selenium from Wastewater using ZVI and Hybrid ZVI/Iron Oxide Process 

    E-Print Network [OSTI]

    Yang, Zhen

    2012-12-20T23:59:59.000Z

    .-W., Chiu, P.-C (1998). "Nitrate reduction by metallic iron." Water Res. 32: 8. 22. Huang, Y. H., Zhang, T.C (2005). "Effects of dissolved oxygen on formation of corrosion products and concomitant oxygen and nitrate reduction in zero-valent iron systems... Chromatographer ICP-MS Inductively Coupled Plasma Mass Spectroscopy mM Millimole Na Sodium Na2CO3 Sodium Carbonate NaHCO3 Sodium Bicarbonate NH4+ Ammonium Ion NO3- Nitrate Ion NaCl Sodium chloride NaNO3...

  6. Sorption of Arsenic, Mercury, Selenium onto Nanostructured Adsorbent Media and Stabilization via Surface Reactions 

    E-Print Network [OSTI]

    Han, Dong Suk

    2011-02-22T23:59:59.000Z

    as pH increased. In addition, a surface complexation model (SCM) based on the diffuse layer model (DLM) was used to predict arsenic adsorption envelopes by NTAs under various environmental conditions. The SCM for As(III, V) adsorption by NTAs...

  7. Growing the Tool Box for Medical Imaging: The Selenium-72/Arsenic-72

    Office of Science (SC) Website

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurTheBrookhaven NationalRegionalsResearch »FundingGlenn Seaborg Trail

  8. Final Technical Report: Hawaii Hydrogen Center for Development and Deployment of Distributed Energy Systems

    SciTech Connect (OSTI)

    Rocheleau, Richard E.

    2008-09-30T23:59:59.000Z

    Hydrogen power park experiments in Hawai‘i produced real-world data on the performance of commercialized electrochemical components and power systems integrating renewable and hydrogen technologies. By analyzing the different losses associated with the various equipment items involved, this work identifies the different improvements necessary to increase the viability of these technologies for commercial deployment. The stand-alone power system installed at Kahua Ranch on the Big Island of Hawaii required the development of the necessary tools to connect, manage and monitor such a system. It also helped the electrolyzer supplier to adapt its unit to the stand-alone power system application. Hydrogen fuel purity assessments conducted at the Hawai‘i Natural Energy Institute (HNEI) fuel cell test facility yielded additional knowledge regarding fuel cell performance degradation due to exposure to several different fuel contaminants. In addition, a novel fitting strategy was developed to permit accurate separation of the degradation of fuel cell performance due to fuel impurities from other losses. A specific standard MEA and a standard flow field were selected for use in future small-scale fuel cell experiments. Renewable hydrogen production research was conducted using photoelectrochemical (PEC) devices, hydrogen production from biomass, and biohydrogen analysis. PEC device activities explored novel configurations of ‘traditional’ photovoltaic materials for application in high-efficiency photoelectrolysis for solar hydrogen production. The model systems investigated involved combinations of copper-indium-gallium-diselenide (CIGS) and hydrogenated amorphous silicon (a-Si:H). A key result of this work was the establishment of a robust “three-stage” fabrication process at HNEI for high-efficiency CIGS thin film solar cells. The other key accomplishment was the development of models, designs and prototypes of novel ‘four-terminal’ devices integrating high-efficiency CIGS and a-Si:H with operating features compatible with high-efficiency photoelectrochemical (PEC) water-splitting. The objective of one activity under the hydrogen production from biomass task was to conduct parametric testing of the Pearson gasifier and to determine the effects of gasifier operating conditions on the gas yields and quality. The hydrogen yield from this gasifier was evaluated in a parametric test series over a range of residence times from 0.8 to 2.2 seconds. H2 concentrations as high as 55% (volume) were measured in the product gas at the longer residence times and this corresponds to a hydrogen yield of 90 kg per tonne of bagasse without gas upgrading. The objective of another activity was to develop hot gas clean-up capabilities for the HNEI gasifier test facility to support hydrogen-from-biomass research. The product gas stream at the outlet of the hot gas filter was characterized for concentrations of permanent gas species and contaminants. Biomass feedstock processing activity included a preliminary investigation into methods for processing sugar cane trash at the Puunene Sugar Factory on the island of Maui, Hawaii. The objective of the investigation was to explore treatment methods that would enable the successful use of cane trash as fuel for the production of hydrogen via gasification. Analyses were completed for the technical and economic feasibility of producing biofuel from photosynthetic marine microbes on a commercial scale. Results included estimates for total costs, energy efficiency, and return on investment. The biohydrogen team undertook a comprehensive review of the field and came to what is considered a realistic conclusion. To summarize, continued research is recommended in the fundamentals of the science related to genetic engineering and specific topics to cover knowledge gaps. In the meantime, the team also advocates continued development of related processes which can be linked to pollution control and other real world applications. The extra revenues hydrogen can provide to these multi-product systems can

  9. IEEE Spectrum: Thin-Film Trick Makes Gallium Arsenide Devices Cheap http://spectrum.ieee.org/semiconductors/materials/thinfilm-trick-makes-gallium-arsenide-devices-cheap[5/22/2010 1:39:13 PM

    E-Print Network [OSTI]

    Rogers, John A.

    to build devices--including solar cells and infrared cameras--using highly efficient but notoriously pricey's energy into electricity, while silicon cells max out at about 20 percent efficiency. The problem Electronics for Smart Grid Technologies &... Available... Reducing Physical Verification Cycle Times Available

  10. Chemistry Controls Material's Nanostructure | The Ames Laboratory

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

    and selenium will form selectively into shapes that look like either tadpoles or drumsticks depending on the relative reactivity of the selenium and sulfur precursors. The more...

  11. Atomic layer deposition of Zn(O,S) thin films with tunable electrical properties by oxygen annealing

    E-Print Network [OSTI]

    CIGS-based solar cells use CdS,1,2 a toxic material, as an n-type buffer layer between the p-type CIGS(O,S) buffer layers in CIGS-based solar cells, much research has also been motivated to replace the expensive) is one of the most reliable materials used in thin-film solar cells, but currently the most efficient

  12. Presented at the 29th IEEE PVSC, May 20 -24, 2002 2P3.15 : Page 1 of 4

    E-Print Network [OSTI]

    Sites, James R.

    CuInxGa1-xSe2/CdS/ZnO (CIGS) solar cells have been shown to be reliable in the field, relatively low the high efficiency CIGS cells. However, brief treatment is also given to the devices fabricated previously OF CIGS(S)/BUFFER LAYERS FORMED BY THE Cd- PARTIAL ELECTROLYTE PROCESS P.K. Johnson 1 , A.O. Pudov 1 , J

  13. The radiation bio-effects of gallum-72 on leukemic cells via a gallium-transferrin complex

    E-Print Network [OSTI]

    Forbes, Christen Douglas

    1999-01-01T23:59:59.000Z

    Improved methods for treatment of leukemia would be advantageous for patients and the medical community. This thesis reports results of a study of the cytotoxicity of radiolabeled transferrin in cultured leukemic cells. K-562 cells, from...

  14. DESIGN AND ANALYSIS OF AN INTEGRATED PULSE MODULATED S-BAND POWER AMPLIFIER IN GALLIUM NITRIDE PROCESS

    SciTech Connect (OSTI)

    STEVE SEDLOCK

    2012-04-04T23:59:59.000Z

    The design of power amplifiers in any semi-conductor process is not a trivia exercise and it is often encountered that the simulated solution is qualitatively different than the results obtained. Phenomena such as oscillation occurring either in-band or out of band and sometimes at subharmonic intervals, continuous spectrum noticed in some frequency bands, often referred to as chaos, and jumps and hysteresis effects can all be encountered and render a design useless. All of these problems might have been identified through a more rigorous approach to stability analysis. Designing for stability is probably the one area of amplifier design that receives the least amount of attention but incurs the most catastrophic of effects if it is not performed properly. Other parameters such as gain, power output, frequency response and even matching may suitable mitigation paths. But the lack of stability in an amplifier has no mitigating path. In addition to of loss of the design completely there are the increased production cycle costs, costs involved with investigating and resolving the problem and the costs involved with schedule slips or delays resulting from it. The Linville or Rollett stability criteria that many microwave engineers follow and rely exclusively on is not sufficient by itself to ensure a stable and robust design. It will be shown that the universal belief that unconditional stability is obtained through an analysis of the scattering matrix S to determine if 1 and |{Delta}{sub S}| < 1 is only part of the procedure and other tools must be used to validate the criteria. The research shown contributes to the state of the art by developing a more thorough stability design technique for designing amplifiers of any class, whether that be current mode or switch mode, than is currently undertaken with the goal of obtaining first pass design success.

  15. Reflectance-difference spectroscopy of mixed arsenic-rich phases of gallium arsenide ,,001... M. J. Begarney,1

    E-Print Network [OSTI]

    Li, Lian

    rough quali- tative agreement with the experimental data. Based on more recent, first, University of California, Los Angeles, California 90095 2 Department of Physics and Laboratory for Surface closely match the RDS data, discrepancies in the energies and mag- nitudes of spectral features remain

  16. The design, construction, and testing of a nuclear fuel rod thermal simulation system to study gallium/Zircaloy interactions 

    E-Print Network [OSTI]

    Allison, Christopher Curtis

    1999-01-01T23:59:59.000Z

    ) fuel rods. The system uses electrically heated simulated fuel rods inside of a large, natural convection heat exchanger that uses lead-bismuth eutectic (LBE) (45 fluid. The simulated rods consist of small diameter...

  17. Thin films of gallium arsenide on low-cost substrates. Final technical report, July 5, 1976-December 5, 1978

    SciTech Connect (OSTI)

    Ruth, R.P.; Dapkus, P.D.; Dupuis, R.D.; Johnson, R.E.; Moudy, L.A.; Yang, J.J.; Yingling, R.D.

    1980-03-01T23:59:59.000Z

    The MO-CVD technique was applied to the growth of thin films of GaAs and GaAl As on inexpensive polycrystalline or amorphous substrate materials (primarily glasses and metals) for use in fabrication of large-area low-cost photovoltaic device structures. Trimethylgallium, arsine, and trimethylaluminum are mixed in appropriate concentrations at room temperature in the gaseous state and pyrolyzed at the substrate, which is heated in a vertical reactor chamber to temperatures of 700 to 750/sup 0/C, to produce the desired film composition and properties. Studies of the properties of grain boundaries in polycrystalline GaAs films by the use of transport measurements as a function of temperature indicated that the grain boundary regions are depleted of majority carriers by a large density of neutral traps at the grain boundary interface, causing a barrier to majority carrier flow in the material. Schottky-barrier solar cells of approx. 3 percent efficiency (simulated AM0 illumination, no AR coating) were demonstrated on thin-film polycrystalline GaAs n/n/sup +/ structures on Mo sheet, Mo film/glass, and graphite substrates. Substantial enhancement of average grain size in polycrystalline MO-CVD GaAs films on Mo sheet was obtained by the addition of HCl to the growth atmosphere during deposition. Extensive investigation of polycrystalline thin-film p-n junctions indicated that the forward voltage of such devices is apparently limited to 0.5 to 0.6V. A laboratory-type deposition apparatus for the formation of TiO/sub 2/ antireflection (AR) coatings by pyrolysis of titanium isopropoxide was assembled and tested. Detailed analyses were made of the materials and labor costs involved in the laboratory-scale fabrication of MO-CVD thin-film GaAs solar cells. Details are presented. (WHK)

  18. The overexpression of NADPH-producing enzymes counters the oxidative stress evoked by gallium, an iron mimetic

    E-Print Network [OSTI]

    Appanna, Vasu

    ), an iron (Fe) mimetic promoted an oxidative environment and elicited an antioxidative response shown to result in unregu- lated ROS production (Huang 2003). For instance, the amyloid b-peptide

  19. Electrical and Optical Properties of Transparent Conducting Homologous Compounds in the IndiumGalliumZinc Oxide System

    E-Print Network [OSTI]

    Poeppelmeier, Kenneth R.

    , smart windows, and solar cells. Tin-doped indium oxide (ITO) is the commercial TCO of choice. ITO thin TRANSPARENT conducting oxides (TCOs) are used in a wide variety of applications, such as flat-panel displays, and lower cost are desired for use in demanding ap- plications such as next-generation flat-panel displays

  20. Velocity distribution function of sputtered gallium atoms during inductively coupled argon plasma treatment of a GaAs surface

    SciTech Connect (OSTI)

    Despiau-Pujo, Emilie; Chabert, Pascal; Ramos, Raphaeel; Cunge, Gilles; Sadeghi, Nader [Laboratoire de Physique des Plasmas, Ecole Polytechnique, 91128 Palaiseau (France); Laboratoire des Technologies de la Microelectronique, CNRS, 38054 Grenoble (France)

    2009-03-15T23:59:59.000Z

    A GaN laser diode at 403.3 nm is used to measure the velocity distribution function (vdf) of Ga atoms sputtered from a radio-frequency biased GaAs substrate in a low pressure inductively coupled plasma (ICP) argon discharge. To investigate both perpendicular (V{sub z} normal to wafer) and longitudinal (V{sub x} parallel to wafer) velocity components, laser induced fluorescence (LIF) measurements are performed in the z direction and atomic absorption spectroscopy (AAS) in the x direction. The longitudinal vdf of Ga sputtered atoms is very close to a Lorentzian function with V{sub x} comprised between 0 and 7500 m s{sup -1}, while the perpendicular velocities V{sub z} can reach 10 000 m s{sup -1}. Experimental results are compared to molecular dynamics (MD) simulations of Ar{sup +} ion sputtering of GaAs under 200 eV bombardment. MD predictions and experiments are in fairly good agreement, which confirms the existence of products sputtered from the surface with kinetic energies larger than 10 eV. In etching processes dominated by physical bombardment, these energetic atoms could alter passivation layers on sidewalls and be responsible for defects observed in nanodevices. The best fit of the Doppler-broadened LIF and AAS profiles with the vdfs predicted by sputtering theory allows one to estimate the surface binding energy of Ga atoms in GaAs, E{sub b}, to be around 3 eV.

  1. Precursors for formation of copper selenide, indium selenide, copper indium diselenide, and/or copper indium gallium diselenide films

    DOE Patents [OSTI]

    Curtis, Calvin J; Miedaner, Alexander; Van Hest, Maikel; Ginley, David S

    2014-11-04T23:59:59.000Z

    Liquid-based precursors for formation of Copper Selenide, Indium Selenide, Copper Indium Diselenide, and/or copper Indium Galium Diselenide include copper-organoselenides, particulate copper selenide suspensions, copper selenide ethylene diamine in liquid solvent, nanoparticulate indium selenide suspensions, and indium selenide ethylene diamine coordination compounds in solvent. These liquid-based precursors can be deposited in liquid form onto substrates and treated by rapid thermal processing to form crystalline copper selenide and indium selenide films.

  2. The influence of random indium alloy fluctuations in indium gallium nitride quantum wells on the device behavior

    SciTech Connect (OSTI)

    Yang, Tsung-Jui; Wu, Yuh-Renn, E-mail: yrwu@ntu.edu.tw [Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Shivaraman, Ravi; Speck, James S. [Department of Materials, University of California, Santa Barbara, California 93106 (United States)

    2014-09-21T23:59:59.000Z

    In this paper, we describe the influence of the intrinsic indium fluctuation in the InGaN quantum wells on the carrier transport, efficiency droop, and emission spectrum in GaN-based light emitting diodes (LEDs). Both real and randomly generated indium fluctuations were used in 3D simulations and compared to quantum wells with a uniform indium distribution. We found that without further hypothesis the simulations of electrical and optical properties in LEDs such as carrier transport, radiative and Auger recombination, and efficiency droop are greatly improved by considering natural nanoscale indium fluctuations.

  3. THSE DE DOCTORAT Spcialit Physique

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    -thin GaAs and CIGS solar cells soutenue le 18 Décembre 2013 Composition du jury : M. PELOUARD Jean-Luc LPN

  4. Novel Materials Development for Polycrystalline Thin-Film Solar Cells: Final Subcontract Report, 26 July 2004--15 June 2008

    SciTech Connect (OSTI)

    Keszler, D. A.; Wager, J. F.

    2008-11-01T23:59:59.000Z

    Focus on player interfacial assessment using Schottky barrier and heterojunction theory, and analysis of p-windows for CIGS and CdTe cells.

  5. Synthesis and Characterization of Earth Abundant and Nontoxic Metal Chalcogenides Produced via Aerosol Spray Pyrolysis for Photovoltaic Applications

    E-Print Network [OSTI]

    Davis, Patrick John

    2013-01-01T23:59:59.000Z

    and Characterization of Earth Abundant and Nontoxic Metaland Characterization of Earth Abundant and Nontoxic Metalalternatives to CIGS with all earth abundant and non-toxic

  6. amiga project quantification: Topics by E-print Network

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

    of the isolation of 950 CIG galaxies CERN Preprints Summary: The role of the environment on galaxy evolution is still not fully understood. In order to quantify and...

  7. Synthesis and Characterization of Earth Abundant and Nontoxic Metal Chalcogenides Produced via Aerosol Spray Pyrolysis for Photovoltaic Applications

    E-Print Network [OSTI]

    Davis, Patrick John

    2013-01-01T23:59:59.000Z

    Renewable Energy Laboratory. CIGS PV Technology: Challenges, Opportunities, and Potential.renewable energy has a lot of room for growth, and solar energy has an even greater potential.

  8. additional cu layer: Topics by E-print Network

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

    PX-CIGS used in photovoltaicphotovoltaic solar cells. The ef?ciency of labora- tory thin-?photovoltaic device. Spectroscopic ellipsometry measurements of polycrystalline...

  9. PHYSICAL REVIEW B 90, 115209 (2014) Computational search for direct band gap silicon crystals

    E-Print Network [OSTI]

    Lee, Jooyoung

    2014-01-01T23:59:59.000Z

    of microns thick, while solar cells made from direct band gap materials (such as CdTe, CIGS, or CZTS) can

  10. Microsoft Word - FY 2003 Annual Report Rev10 02_10_04.doc

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

    formulation, which has been under development at Sandia since 1997. Efficient Photovoltaic Solar Cells Becoming Widely Deployed CIGS (Cu(In,Ga)Se 2 ) is a...

  11. Ecosystem-scale Selenium Model for the San Francisco Bay-Delta Regional Ecosystem Restoration Implementation Plan

    E-Print Network [OSTI]

    Presser, Theresa S.; Luoma, Samuel N.

    2013-01-01T23:59:59.000Z

    Rivers: implications for ecosystem restoration: Final reportto CALFED. Ecosystem Restoration Program Agreement No.support tools to guide ecosystem restoration planning and

  12. Chemical modeling of arsenic(III, V) and selenium(IV, VI) adsorption by soils surrounding ash disposal facilities

    SciTech Connect (OSTI)

    Goldberg, S.; Hyun, S.; Lee, L.S. [USDA, Riverside, CA (United States). US Salinity Laboratory

    2008-11-15T23:59:59.000Z

    Leachate derived from coal ash disposal facilities is a potential anthropogenic source of As and Se to the environment. To establish a practical framework for predicting attenuation and transport of As and Se in ash leachates, the adsorption of As(III), As(V), Se(IV), and Se(VI) had been characterized in prior studies for 18 soils obtained downgradient from ash landfill sites and representing a wide range of soil properties. The constant capacitance model was applied for the first time to describe As(III), As(V), Se(IV), and Se(VI) adsorption on soils as a function of equilibrium solution As(III), As(V), Se(IV), and Se(VI) concentrations. Prior applications of the model had been restricted to describing Se(IV) and As(V) adsorption by soils as a function of solution pH. The constant capacitance model was applied for the first time to describe As(III) and Se(VI) adsorption by soils. The model was able to describe adsorption of these ions on all soils as a function of solution ion concentration by optimizing only one adjustable parameter, the anion surface complexation constant. This chemical model represents an advancement over adsorption isotherm equation approaches that contain two empirical adjustable parameters. Incorporation of these anion surface complexation constants obtained with the constant capacitance model into chemical speciation transport models will allow simulation of soil solution anion concentrations under diverse environmental and agricultural conditions.

  13. Cross-sectional transmission electron microscopy study of femtosecond laser-irradiated selenium-doped 'black' silicon

    E-Print Network [OSTI]

    Reading, Arthur H. (Arthur Henry)

    2009-01-01T23:59:59.000Z

    'Black silicon' refers to silicon that has been treated in a laser-ablation process to incorporate large amounts of chalcogen dopants. The material has been found to have greatly increased absorbance of visible and infared ...

  14. Solid-to-solid phase transformations of nanostructured selenium-tin thin films induced by thermal annealing in oxygen atmosphere

    SciTech Connect (OSTI)

    Serra, A. [Physics Applied to Material Science interdepartmental Laboratory (PAMS-Lab) - Dipartimento di Beni Culturali - Universitŕ del Salento - Lecce (Italy); Rossi, M. [Dipartimento Scienze di Base ed Applicate all'Ingegneria, and CNIS - Sapienza Universitŕ di Roma, Roma (Italy); Buccolieri, A.; Manno, D. [Physics Applied to Material Science interdepartmental Laboratory (PAMS-Lab) - Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali - Universitŕ del Salento - Lecce (Italy)

    2014-06-19T23:59:59.000Z

    The structural and morphological evolution of nanostructured thin films obtained from thermal evaporation of polycrystalline Sn-Se starting charge as a function of the subsequent annealing temperature in an oxygen flow has been analysed. High-resolution transmission electron microscopy, small area electron diffraction, digital image processing, x-ray diffraction and Raman spectroscopy have been employed in order to investigate the structure and the morphology of the obtained films. The results evidenced, in the temperature range from RT to 500°C, the transition of the material from a homogeneous mixture of SnSe and SnSe{sub 2} nanocrystals, towards a homogeneous mixture of SnO{sub 2} and SeO{sub 2} nanocrystals, with an intermediate stage in which only SnSe{sub 2} nanocrystals are present.

  15. Ecosystem-scale Selenium Model for the San Francisco Bay-Delta Regional Ecosystem Restoration Implementation Plan

    E-Print Network [OSTI]

    Presser, Theresa S.; Luoma, Samuel N.

    2013-01-01T23:59:59.000Z

    79 p + 9 appendices. Cutter GA. Bruland KW. 1984. The marinerisks are likely (Cutter and Bruland 1984); hence, there are

  16. 1970. Analysis of arsenic and selenium in marine raw materials. J. Sci. Food Agric. 21:242-247.

    E-Print Network [OSTI]

    were collected in the intake canal ofthe Carolina Power and Light Company generating plant in the Cape .Fear Rivel' estuary west of buoy 19 on 11 October 1977. Bottom type was silty-sand at depth of 4 m

  17. Selenium Fractionation and Cycling in the Intertidal Zone of the Carquinez Strait - October 1995 to December 1995

    E-Print Network [OSTI]

    Zawislanski, P.T.

    2010-01-01T23:59:59.000Z

    of the mechanism by which refinery Se enters the food web isIt is also not clear how refinery effluent Se, released asThe analysis of a Shell Refinery effluent sample reported in

  18. Ecosystem-scale Selenium Model for the San Francisco Bay-Delta Regional Ecosystem Restoration Implementation Plan

    E-Print Network [OSTI]

    Presser, Theresa S.; Luoma, Samuel N.

    2013-01-01T23:59:59.000Z

    both agricultural and oil refinery sources of Se (SFBRWQCBSe • hydrodynamics • oil refinery effluent • North Bay •1) internal inputs of oil refinery wastewaters from pro-

  19. Selenium Fractionation and Cycling in the Intertidal Zone of the Carquinez Strait - October 1995 to December 1995

    E-Print Network [OSTI]

    Zawislanski, P.T.

    2010-01-01T23:59:59.000Z

    wet, almost flowing mudflat sediments and root- dominatedthe largest expanse of mudflat possible. In the laboratory,sediments on the surface of mudflat region are resuspended,

  20. On the Mass Eigenstate Composition of the 8B Neutrinos from the Sun

    E-Print Network [OSTI]

    A. Kopylov; V. Petukhov

    2007-04-19T23:59:59.000Z

    The present data of gallium experiments provide indirectly the only experimental limit on the fraction of $\

  1. Occupational Medicine Implications of Engineered Nanoscale Particulate Matter

    E-Print Network [OSTI]

    Kelly, Richard J.

    2008-01-01T23:59:59.000Z

    Titanium Ytterbium Zirconium Animony Boron Carbon Cobalt Erbium Gallium Hafnium Iridium Lead Magnesium Neodymium Nitrogen

  2. STEM CELLS AND DEVELOPMENT Volume 18, Number 2, 2009

    E-Print Network [OSTI]

    Athanasiou, Kyriacos

    , selenium, and bovine serum albumin (BSA)], dexamethasone, ascorbic acid, and pyruvate [7­10]. Using

  3. Method for the chemical separation of GE-68 from its daughter Ga-68

    DOE Patents [OSTI]

    Fitzsimmons, Jonathan M.; Atcher, Robert W.

    2010-06-01T23:59:59.000Z

    The present invention is directed to a generator apparatus for separating a daughter gallium-68 radioisotope substantially free of impurities from a parent gernanium-68 radioisotope, including a first resin-containing column containing parent gernanium-68 radioisotope and daughter gallium-68 radioisotope, a source of first eluent connected to said first resin-containing column for separating daughter gallium-68 radioisotope from the first resin-containing column, said first eluent including citrate whereby the separated gallium is in the form of gallium citrate, a mixing space connected to said first resin-containing column for admixing a source of hydrochloric acid with said separated gallium citrate whereby gallium citrate is converted to gallium tetrachloride, a second resin-containing column for retention of gallium-68 tetrachloride, and, a source of second eluent connected to said second resin-containing column for eluting the daughter gallium-68 radioisotope from said second resin-containing column.

  4. Lessons from IT Ecosystems Michael Kster

    E-Print Network [OSTI]

    Zachmann, Gabriel

    -Transport-Systems Smart-Energy-Systems etc. Smart Airport as a smaller instance of a Smart City Michael Köster · CIG, TU and interact massively. IT Ecosystem: analogue to biological ecosystems based on the balance between and continuously evolving IT Ecosystems requires deep understanding of this balance. Michael Köster · CIG, TU

  5. Optimization of chemical bath deposited CdS thin films using nitrilotriacetic acid as a complexing agent

    E-Print Network [OSTI]

    Chow, Lee

    thin film solar cells based on CdTe or CIGS [1,2]. CdS has also been used in other applications. The highest efficiencies reported for both CdTe and CIGS solar cells were obtained when chemical bath is known to greatly enhance the performance of CdS windows used in the above mentioned solar cells

  6. RealReal heterojunctionsheterojunctions Schottky barrier current

    E-Print Network [OSTI]

    Pulfrey, David L.

    -EFFICIENCY CDTE AND CIGS THIN-FILM SOLAR CELLS: HIGHLIGHTS AND CHALLENGES. National Renewable Energy Laboratory1 RealReal heterojunctionsheterojunctions LECTURE 9 · Schottky barrier current · CdS/CIGS · Energy is the forward-bias current? #12;33 HeterostructureHeterostructure, thin film, cells: a lower, thin film, cells

  7. Subscriber access provided by UNIV TORONTO Chemistry of Materials is published by the American Chemical Society. 1155

    E-Print Network [OSTI]

    of solar cells, is sought. An attractive alternative is the synthesis of nontoxic CuInS2, CuInSe2, and Cu(InGa)Se2 (CIGS). Polycrystalline CIGS films offer an alternative solar energy conversion material-generation solar cells having >30% AM1.5 power conversion efficiencies can be achieved by stacking semiconductors

  8. Z .Thin Solid Films 372 2000 212 217 Z .Na in selenized Cu In,Ga Se on Na-containing and Na-free2

    E-Print Network [OSTI]

    Rockett, Angus

    of the substrate glass on standard Z . Z .production Cu In Ga Se CIGS -based solar cells fabricated by selenization; Selenides2 1. Introduction Z .Production of large quantities of Cu In Ga Se1yx x 2 Z . Z .CIGS -based solar solar cell performance. Impurities, both U Corresponding author. Tel.: q1-217-333-0417; fax: q1

  9. Crystal and electronic band structure of Cu2ZnSnX4 ,,X=S and Se... photovoltaic absorbers: First-principles insights

    E-Print Network [OSTI]

    Gong, Xingao

    components, and the band gap is usually not optimal for high efficiency CIGS solar cells. Currently, designing and synthesizing novel, high-efficiency, and low cost solar cell absorbers to replace CIGS has.1063/1.3074499 An ideal thin-film solar cell absorber material should have a direct band gap around 1.3­1.5 e

  10. Published on Web Date: January 18, 2011 r 2011 American Chemical Society 212 DOI: 10.1021/jz101565j |J. Phys. Chem. Lett. 2011, 2, 212217

    E-Print Network [OSTI]

    Goddard III, William A.

    compound of the promising CIGS Cu(InxGa1-x)Se2 solar devices, that LDA and GGA obtain gaps of 0.0-0.01 e in these studies was to study the properties of the Cu(InxGa1-x)Se2 (CIGS) class ofsolar cells, pioneered by NREL

  11. Thermodynamics, Entropy, Information and the Efficiency of Solar Cells

    E-Print Network [OSTI]

    Abrams, Zeev R.

    2012-01-01T23:59:59.000Z

    CIGS, so the addition of the dc layer would not alter the material choice for a solar cell.solar cell, the use of GaAs has recently become feasible due to scalable manufacturing techniques, and compound materials such as CIGS (

  12. Characterization of Damp-Heat Degradation of CuInGaSe2 Solar Cell Components and Devices by (Electrochemical) Impedance Spectroscopy: Preprint

    SciTech Connect (OSTI)

    Pern, F. J. J.; Noufi, R.

    2011-09-01T23:59:59.000Z

    This work evaluated the capability of (electrochemical) impedance spectroscopy (IS, or ECIS as used here) to monitor damp heat (DH) stability of contact materials, CuInGaSe2 (CIGS) solar cell components, and devices. Cell characteristics and its variation of the CIGS devices were also examined by the ECIS.

  13. Photovoltaic Materials

    SciTech Connect (OSTI)

    Duty, C.; Angelini, J.; Armstrong, B.; Bennett, C.; Evans, B.; Jellison, G. E.; Joshi, P.; List, F.; Paranthaman, P.; Parish, C.; Wereszczak, A.

    2012-10-15T23:59:59.000Z

    The goal of the current project was to help make the US solar industry a world leader in the manufacture of thin film photovoltaics. The overall approach was to leverage ORNL’s unique characterization and processing technologies to gain a better understanding of the fundamental challenges for solar cell processing and apply that knowledge to targeted projects with industry members. ORNL has the capabilities in place and the expertise required to understand how basic material properties including defects, impurities, and grain boundaries affect the solar cell performance. ORNL also has unique processing capabilities to optimize the manufacturing process for fabrication of high efficiency and low cost solar cells. ORNL recently established the Center for Advanced Thin-film Systems (CATS), which contains a suite of optical and electrical characterization equipment specifically focused on solar cell research. Under this project, ORNL made these facilities available to industrial partners who were interested in pursuing collaborative research toward the improvement of their product or manufacturing process. Four specific projects were pursued with industrial partners: Global Solar Energy is a solar industry leader in full scale production manufacturing highly-efficient Copper Indium Gallium diSelenide (CIGS) thin film solar material, cells and products. ORNL worked with GSE to develop a scalable, non-vacuum, solution technique to deposit amorphous or nanocrystalline conducting barrier layers on untextured stainless steel substrates for fabricating high efficiency flexible CIGS PV. Ferro Corporation’s Electronic, Color and Glass Materials (“ECGM”) business unit is currently the world’s largest supplier of metallic contact materials in the crystalline solar cell marketplace. Ferro’s ECGM business unit has been the world's leading supplier of thick film metal pastes to the crystalline silicon PV industry for more than 30 years, and has had operational cells and modules in the field for 25 years. Under this project, Ferro leveraged world leading analytical capabilities at ORNL to characterize the paste-to-silicon interface microstructure and develop high efficiency next generation contact pastes. Ampulse Corporation is developing a revolutionary crystalline-silicon (c-Si) thin-film solar photovoltaic (PV) technology. Utilizing uniquely-textured substrates and buffer materials from the Oak Ridge National Laboratory (ORNL), and breakthroughs in Hot-Wire Chemical Vapor Deposition (HW-CVD) techniques in epitaxial silicon developed at the National Renewable Energy Laboratory (NREL), Ampulse is creating a solar technology that is tunable in silicon thickness, and hence in efficiency and economics, to meet the specific requirements of multiple solar PV applications. This project focused on the development of a high rate deposition process to deposit Si, Ge, and Si1-xGex films as an alternate to hot-wire CVD. Mossey Creek Solar is a start-up company with great expertise in the solar field. The primary interest is to create and preserve jobs in the solar sector by developing high-yield, low-cost, high-efficiency solar cells using MSC-patented and -proprietary technologies. The specific goal of this project was to produce large grain formation in thin, net-shape-thickness mc-Si wafers processed with high-purity silicon powder and ORNL's plasma arc lamp melting without introducing impurities that compromise absorption coefficient and carrier lifetime. As part of this project, ORNL also added specific pieces of equipment to enhance our ability to provide unique insight for the solar industry. These capabilities include a moisture barrier measurement system, a combined physical vapor deposition and sputtering system dedicated to cadmium-containing deposits, adeep level transient spectroscopy system useful for identifying defects, an integrating sphere photoluminescence system, and a high-speed ink jet printing system. These tools were combined with others to study the effect of defects on the performance of crystalline silicon and

  14. Effects of gallium doping on properties of a-plane ZnO films on r-plane sapphire substrates by plasma-assisted molecular beam epitaxy

    SciTech Connect (OSTI)

    Han, Seok Kyu; Lee, Hyo Sung; Lim, Dong Seok; Hong, Soon-Ku; Yoon, Nara; Oh, Dong-Cheol; Ahn, Byung Jun; Song, Jung-Hoon; Yao, Takafumi [Department of Advanced Materials Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Graduate School of Green Energy Technology, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Department of Advanced Materials Engineering, Chungnam National University, Daejeon 305-764, Republic of Korea and Graduate School of Green Energy Technology, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Center for Optoelectronic Materials and Devices, Department of Defense Science and Technology, Hoseo University, Cheonan 330-713 (Korea, Republic of); Department of Physics, Kongju National University, Gongju 314-701 (Korea, Republic of); Center for Interdisciplinary Research, Tohoku University, Sendai 980-8587 (Japan)

    2011-05-15T23:59:59.000Z

    The authors report on the structural, optical, and electrical properties of Ga-doped a-plane (1120) ZnO films grown by plasma-assisted molecular beam epitaxy. Ga doping level was controlled by changing the Ga cell temperatures from 350 to 470 deg. C with an interval of 30 deg. C. With up to Ga cell temperatures of 440 deg. C, single crystalline Ga-doped a-plane ZnO films were grown; however, the sample with a Ga cell temperature of 470 deg. C showed polycrystalline features. The typical striated surface morphology normally observed from undoped ZnO films disappeared with Ga doping. ZnO films doped with Ga cell temperatures up to 440 deg. C did not show a significant change in full width at half maximum (FWHM) values of (1120) x-ray rocking curves by doping. The smallest FWHM values were 0.433 deg. ({phi}=90 deg.) and 0.522 deg. ({phi}=0 deg. ) for the sample with a Ga cell temperature of 350 deg. C. The polycrystalline ZnO film with excessive Ga doping at the Ga cell temperature of 470 deg. C showed significantly increased FWHM values. Hall measurements at room temperature (RT) revealed that electron concentration began to be saturated at the Ga cell temperature of 440 deg. C and electron mobility was drastically reduced at the Ga cell temperature of 470 deg. C. The carrier concentration of Ga-doped ZnO films were controlled from 7.2x10{sup 18} to 3.6x10{sup 20} cm{sup -3}. Anisotropic electrical properties (carrier concentration and Hall mobility) were observed in measurements by the van der Pauw method depending on the direction (c- or m-direction) for the undoped sample but not observed for the doped samples. RT photoluminescence (PL) spectra from the Ga-doped single crystalline ZnO films showed dominant near band edge (NBE) emissions with negligibly deep level emission. The NBE intensity in PL spectra increases with Ga doping.

  15. Formation of Porous Layers by Electrochemical Etching of Germanium and Gallium Arsenide for Cleave Engineered Layer Transfer (CELT) Application in High Efficiency Multi-Junction Solar Cells

    E-Print Network [OSTI]

    Fong, David Michael

    2012-01-01T23:59:59.000Z

    photovoltaic devices with a world record efficiency ofhigh efficiencies as compared to traditional photovoltaic

  16. Gallium Lighting, LLC, Accepts Inaugural Position on the Industry Advisory Board of UC-Light Center to Help Bring Wireless Data

    E-Print Network [OSTI]

    -Light Center to Help Bring Wireless Data Communications Capabilities to LED Lights Fayetteville, GA ­ February for their Energy Star rated products and produce some of the most energy efficient, environmentally friendly on the Industry Advisory Board for the Center for Ubiquitous Communication by Light (UC-Light Center) based

  17. Inversion by metalorganic chemical vapor deposition from N- to Ga-polar gallium nitride and its application to multiple quantum well light-emitting diodes

    SciTech Connect (OSTI)

    Hosalli, A. M.; Van Den Broeck, D. M.; Bedair, S. M. [Department of Electrical and Computer Engineering, NCSU, Raleigh, North Carolina 27695 (United States)] [Department of Electrical and Computer Engineering, NCSU, Raleigh, North Carolina 27695 (United States); Bharrat, D.; El-Masry, N. A. [Department of Material Science and Engineering, NCSU, Raleigh, North Carolina 27695 (United States)] [Department of Material Science and Engineering, NCSU, Raleigh, North Carolina 27695 (United States)

    2013-12-02T23:59:59.000Z

    We demonstrate a metalorganic chemical vapor deposition growth approach for inverting N-polar to Ga-polar GaN by using a thin inversion layer grown with high Mg flux. The introduction of this inversion layer allowed us to grow p-GaN films on N-polar GaN thin film. We have studied the dependence of hole concentration, surface morphology, and degree of polarity inversion for the inverted Ga-polar surface on the thickness of the inversion layer. We then use this approach to grow a light emitting diode structure which has the MQW active region grown on the advantageous N-polar surface and the p-layer grown on the inverted Ga-polar surface.

  18. J. Phys.: Condens. Matter 9 (1997) 95179525. Printed in the UK PII: S0953-8984(97)82806-8 An interatomic potential study of the properties of gallium

    E-Print Network [OSTI]

    Pandey, Ravi

    1997-01-01T23:59:59.000Z

    energies of intrinsic point defects reveal that vacancies are the dominant native defects in GaN. Lastly Gale Department of Physics, Michigan Technological University, Houghton, MI 49931, USA Department of Chemistry, Imperial College of Science, Technology and Medicine, South Kensington, London SW7 2AY, UK

  19. Preparation of silicon substrates for gallium-arsenide solar cells by electron-beam-pulse processing. Annual technical report, March 15, 1980-March 15, 1981

    SciTech Connect (OSTI)

    Tobin, S.P.

    1981-05-01T23:59:59.000Z

    In the past year a process has been developed for creating high-quality epitaxial layers of germanium on silicon substrates using rapid heating and cooling with a pulsed electron beam. This single-crystal germanium coating is the key to the production of high efficiency GaAs solar cells on low-cost silicon substrates in an economical manner. Thin (less than or equal to 1 ..mu..m) layers of Ge have been deposited on Si wafers by chemical vapor deposition (CVD) in single-crystal form or by vacuum evaporation in amorphous or polycrystalline form. The CVD films have given the best results, with good crystallinity and electrical properties as deposited. A persistent problem with surface roughness in the as-deposited films has been overcome by pulsed electron beam melting of the near-surface region in time periods on the order of a microsecond. The brief molten period smooths the surface features without compromising the crystallinity, electrical properties, or interfacial abruptness of the Ge film. These layers are of a quality suitable for further evaluation by GaAs growth and cell processing in the next phase of the program. Pulsed electron beam processing also serves a vital function for the evaporated Ge films, which are melted by the beam and recrystallized on the Si substrates, epitaxial single crystal Ge layers result from amorphous or polycrystalline starting films. To date results have not been as satisfactory as for CVD films; contamination from several sources has been identified as a problem. Many of these sources have been eliminated, so that a decision on the intrinsic limitations of the evaporated film approach should be made in the near future.

  20. Gallium as a Possible Target Material for a Muon Collider or Neutrino Factory X. Ding, D. Cline, UCLA, Los Angeles, CA 90095, USA

    E-Print Network [OSTI]

    McDonald, Kirk

    .J. Weggel, Particle Beam Lasers, Inc., Northridge, CA 91324, USA V.B. Graves, ORNL, Oak Ridge, TN 37830, USA the peak for nickel), Liquid state at relatively low temperature (melting point = 29.8 C) , Potential plane at z = 50 m. For this analysis we select all pions and muons with 40