National Library of Energy BETA

Sample records for gallium diselenide cigs

  1. Improving the efficiency of copper indium gallium (Di-)selenide (CIGS) solar cells through integration of a moth-eye textured resist with a refractive index similar to aluminum doped zinc oxide

    SciTech Connect (OSTI)

    Burghoorn, M.; Kniknie, B.; Deelen, J. van; Ee, R. van; Xu, M.; Vroon, Z.; Belt, R. van de; Buskens, P. E-mail: buskens@dwi.rwth-aachen.de

    2014-12-15

    Textured transparent conductors are widely used in thin-film silicon solar cells. They lower the reflectivity at interfaces between different layers in the cell and/or cause an increase in the path length of photons in the Si absorber layer, which both result in an increase in the number of absorbed photons and, consequently, an increase in short-circuit current density (J{sub sc}) and cell efficiency. Through optical simulations, we recently obtained strong indications that texturing of the transparent conductor in copper indium gallium (di-)selenide (CIGS) solar cells is also optically advantageous. Here, we experimentally demonstrate that the J{sub sc} and efficiency of CIGS solar cells with an absorber layer thickness (d{sub CIGS}) of 0.85 μm, 1.00 μm and 2.00 μm increase through application of a moth-eye textured resist with a refractive index that is sufficiently similar to AZO (n{sub resist} = 1.792 vs. n{sub AZO} = 1.913 at 633 nm) to avoid large optical losses at the resist-AZO interface. On average, J{sub sc} increases by 7.2%, which matches the average reduction in reflection of 7.0%. The average relative increase in efficiency is slightly lower (6.0%). No trend towards a larger relative increase in J{sub sc} with decreasing d{sub CIGS} was observed. Ergo, the increase in J{sub sc} can be fully explained by the reduction in reflection, and we did not observe any increase in J{sub sc} based on an increased photon path length.

  2. Copper Indium Gallium Diselenide | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    Since its initial development, copper indium diselenide (CuInSe2) thin-film technology has been considered promising for solar cells because of its favorable electronic and optical ...

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

    DOE Patents [OSTI]

    Bhattacharya, Raghu N.; Contreras, Miguel A.; Keane, James; Tennant, Andrew L. , Tuttle, John R.; Ramanathan, Kannan; Noufi, Rommel

    1998-08-08

    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.

  4. Precursors for formation of copper selenide, indium selenide, copper indium diselenide, and/or copper indium gallium diselenide films

    SciTech Connect (OSTI)

    Curtis, Calvin J; Miedaner, Alexander; Van Hest, Maikel; Ginley, David S

    2014-11-04

    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.

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

    DOE Patents [OSTI]

    Bhattacharya, Raghu N.; Hasoon, Falah S.; Wiesner, Holm; Keane, James; Noufi, Rommel; Ramanathan, Kannan

    1999-02-16

    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.

  6. Characterization of Cu(In,Ga)Se2 (CIGS) films with varying gallium ratios

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

    Claypoole, Jesse; Peace, Bernadette; Sun, Neville; Dwyer, Dan; Eisaman, Matthew D.; Haldar, Pradeep; Efstathiadis, Harry

    2015-09-05

    Cu(In1-x,Gax)Se2 (CIGS) absorber layers were deposited on molybdenum (Mo) coated soda-lime glass substrates with varying Ga content (described as Ga/(In+Ga) ratios) with respect to depth. As the responsible mechanisms for the limitation of the performance of the CIGS solar cells with high Ga contents are not well understood, the goal of this work was to investigate different properties of CIGS absorber films with Ga/(In+Ga) ratios varied between 0.29 and 0.41 (as determined by X-ray florescence spectroscopy (XRF)) in order to better understand the role that the Ga content has on film quality. The Ga grading in the CIGS layer hasmore » the effect causing a higher bandgap toward the surface and Mo contact while the band gap in the middle of the CIGS layer is lower. Also, a wider and larger Ga/(In+Ga) grading dip located deeper in the CIGS absorber layers tend to produce larger grains in the regions of the films that have lower Ga/(In+Ga) ratios. It was found that surface roughness decreases from 51.2 nm to 41.0 nm with increasing Ga/(In+Ga) ratios. However, the surface roughness generally decreases if the Ga grading occurs deeper in the absorber layer.« less

  7. Characterization of Cu(In,Ga)Se2 (CIGS) films with varying gallium ratios

    SciTech Connect (OSTI)

    Claypoole, Jesse; Peace, Bernadette; Sun, Neville; Dwyer, Dan; Eisaman, Matthew D.; Haldar, Pradeep; Efstathiadis, Harry

    2015-09-05

    Cu(In1-x,Gax)Se2 (CIGS) absorber layers were deposited on molybdenum (Mo) coated soda-lime glass substrates with varying Ga content (described as Ga/(In+Ga) ratios) with respect to depth. As the responsible mechanisms for the limitation of the performance of the CIGS solar cells with high Ga contents are not well understood, the goal of this work was to investigate different properties of CIGS absorber films with Ga/(In+Ga) ratios varied between 0.29 and 0.41 (as determined by X-ray florescence spectroscopy (XRF)) in order to better understand the role that the Ga content has on film quality. The Ga grading in the CIGS layer has the effect causing a higher bandgap toward the surface and Mo contact while the band gap in the middle of the CIGS layer is lower. Also, a wider and larger Ga/(In+Ga) grading dip located deeper in the CIGS absorber layers tend to produce larger grains in the regions of the films that have lower Ga/(In+Ga) ratios. It was found that surface roughness decreases from 51.2 nm to 41.0 nm with increasing Ga/(In+Ga) ratios. However, the surface roughness generally decreases if the Ga grading occurs deeper in the absorber layer.

  8. 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.

    2010-08-01

    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.

  9. PROJECT PROFILE: Manufacturing and Reliability Science for CIGS...

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

    This project aims to overcome the largest challenges to investor confidence and long product lifetime in copper indium gallium selenide (CIGS): meta-stability, potential-induced ...

  10. 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.

    2014-11-01

    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.

  11. NREL: Process Development and Integration Laboratory - Copper...

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

    Copper Indium Gallium Diselenide Cluster Tool Capabilities The Copper Indium Gallium Diselenide (CIGS) cluster tool in the Process Development and Integration Laboratory offers ...

  12. Semi-transparent perovskite solar cells for tandems with silicon and CIGS

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

    Bailie, Colin D.; Christoforo, M. Greyson; Mailoa, Jonathan P.; Bowring, Andrea R.; Unger, Eva L.; Nguyen, William H.; Burschka, Julian; Pellet, Norman; Lee, Jungwoo Z.; Grätzel, Michael; et al

    2014-12-23

    A promising approach for upgrading the performance of an established low-bandgap solar technology without adding much cost is to deposit a high bandgap polycrystalline semiconductor on top to make a tandem solar cell. We use a transparent silver nanowire electrode on perovskite solar cells to achieve a semi-transparent device. We place the semi-transparent cell in a mechanically-stacked tandem configuration onto copper indium gallium diselenide (CIGS) and low-quality multicrystalline silicon (Si) to achieve solid-state polycrystalline tandem solar cells with a net improvement in efficiency over the bottom cell alone. Furthermore, this work paves the way for integrating perovskites into a low-costmore » and high-efficiency (>25%) tandem cell.« less

  13. Semi-transparent perovskite solar cells for tandems with silicon and CIGS

    SciTech Connect (OSTI)

    Bailie, Colin D.; Christoforo, M. Greyson; Mailoa, Jonathan P.; Bowring, Andrea R.; Unger, Eva L.; Nguyen, William H.; Burschka, Julian; Pellet, Norman; Lee, Jungwoo Z.; Grätzel, Michael; Noufi, Rommel; Buonassisi, Tonio; Salleo, Alberto; McGehee, Michael D.

    2014-12-23

    A promising approach for upgrading the performance of an established low-bandgap solar technology without adding much cost is to deposit a high bandgap polycrystalline semiconductor on top to make a tandem solar cell. We use a transparent silver nanowire electrode on perovskite solar cells to achieve a semi-transparent device. We place the semi-transparent cell in a mechanically-stacked tandem configuration onto copper indium gallium diselenide (CIGS) and low-quality multicrystalline silicon (Si) to achieve solid-state polycrystalline tandem solar cells with a net improvement in efficiency over the bottom cell alone. Furthermore, this work paves the way for integrating perovskites into a low-cost and high-efficiency (>25%) tandem cell.

  14. PROJECT PROFILE: Manufacturing and Reliability Science for CIGS

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

    Photovoltaics | Department of Energy Manufacturing and Reliability Science for CIGS Photovoltaics PROJECT PROFILE: Manufacturing and Reliability Science for CIGS Photovoltaics Funding Opportunity: SuNLaMP SunShot Subprogram: Photovoltaics Location: National Renewable Energy Laboratory, Golden, CO Amount Awarded: $4,000,000 This project aims to overcome the largest challenges to investor confidence and long product lifetime in copper indium gallium selenide (CIGS): meta-stability,

  15. Physics-Based Compact Model for CIGS and CdTe Solar Cells: From Voltage-Dependent Carrier Collection to Light-Enhanced Reverse Breakdown: Preprint

    SciTech Connect (OSTI)

    Sun, Xingshu; Alam, Muhammad Ashraful; Raguse, John; Garris, Rebekah; Deline, Chris; Silverman, Timothy

    2015-10-15

    In this paper, we develop a physics-based compact model for copper indium gallium diselenide (CIGS) and cadmium telluride (CdTe) heterojunction solar cells that attributes the failure of superposition to voltage-dependent carrier collection in the absorber layer, and interprets light-enhanced reverse breakdown as a consequence of tunneling-assisted Poole-Frenkel conduction. The temperature dependence of the model is validated against both simulation and experimental data for the entire range of bias conditions. The model can be used to characterize device parameters, optimize new designs, and most importantly, predict performance and reliability of solar panels including the effects of self-heating and reverse breakdown due to partial-shading degradation.

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

    DOE Patents [OSTI]

    Bhattacharya, Raghu Nath

    2007-11-20

    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.

  17. NREL: Photovoltaics Research - Standards Development

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

    Current standards lack specifics on how to precondition cadmium telluride (CdTe) and copper indium gallium diselenide (CIGS) modules so that when tested for reporting conditions, ...

  18. Solibro AB | Open Energy Information

    Open Energy Info (EERE)

    Sweden Zip: 751 21 Sector: Solar Product: Develops thin film solar cells using copper indium gallium diselenide (CIGS). References: Solibro AB1 This article is a stub....

  19. PROJECT PROFILE: Degradation Assessment of Fielded CIGS Photovoltaic...

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

    Degradation Assessment of Fielded CIGS Photovoltaic Module Technologies PROJECT PROFILE: Degradation Assessment of Fielded CIGS Photovoltaic Module Technologies Funding ...

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

    SciTech Connect (OSTI)

    Olsen, L. C.

    2010-03-01

    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.

  1. Nuvosun Inc | Open Energy Information

    Open Energy Info (EERE)

    Nuvosun Inc Place: Palo Alto, California Zip: 94303-4601 Product: California-based copper indium gallium (di)selenide (CIGS) thin film PV maker. References: Nuvosun Inc1 This...

  2. PROJECT PROFILE: Degradation Assessment of Fielded CIGS Photovoltaic Module

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

    Technologies | Department of Energy Degradation Assessment of Fielded CIGS Photovoltaic Module Technologies PROJECT PROFILE: Degradation Assessment of Fielded CIGS Photovoltaic Module Technologies Funding Opportunity: SuNLaMP SunShot Subprogram: Photovoltaics Location: Sandia National Laboratories, Albuquerque, NM Amount Awarded: $3,000,000 CIGS PV cell technology is a promising candidate to exceed SunShot price targets. However, adoption of CIGS has been hindered by significant

  3. Effects of Metastabilities on CIGS Photovoltaic Modules | Department of

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

    Energy Effects of Metastabilities on CIGS Photovoltaic Modules Effects of Metastabilities on CIGS Photovoltaic Modules 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

  4. Cost and Potential of Monolithic CIGS Photovoltaic Modules (Presentati...

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

    Cost and Potential of Monolithic CIGS Photovoltaic Modules IEEE Photovoltaic Specialists Conference, New Orleans Kelsey A. W. Horowitz and Michael Woodhouse June 17, 2015 NREL...

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

    SciTech Connect (OSTI)

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

    2008-05-01

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

  6. 2016 CIG (Computational Infrastructure for Geodynamics) All Hands...

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

    2016 CIG (Computational Infrastructure for Geodynamics) All Hands Meeting Start Date: Jun 17 2016 (All day) to Jun 24 2016 (All day) Location: UC Davis Event Website: https:...

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

    SciTech Connect (OSTI)

    Ramanathan, K.

    2012-03-01

    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.

  8. Final Report - High throughput CIGS solar cell fabrication via...

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

    High throughput CIGS solar cell fabrication via ultra-thin absorber layer with optical ... Contact Materials for Improved Performance CdTe Solar Cells Download the SunShot ...

  9. NREL: Awards and Honors - Lightweight, Flexible, Thin-Film CIGS...

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

    to them, for example, the CIGS systems: Are lighter, more flexible and portable; Are more efficient and reliable; Have two to three times the power-to-weight ratio; Have more than...

  10. Method of junction formation for CIGS photovoltaic devices

    DOE Patents [OSTI]

    Delahoy, Alan E.

    2010-01-26

    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.

  11. Method of junction formation for CIGS photovoltaic devices

    DOE Patents [OSTI]

    Delahoy, Alan E.

    2006-03-28

    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.

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

    Office of Scientific and Technical Information (OSTI)

    CIGS Thin-Film Solar Cell Research at NREL: FY04 Results and Accomplishments Citation Details In-Document Search Title: CIGS Thin-Film Solar Cell Research at NREL: FY04 Results and ...

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

    SciTech Connect (OSTI)

    Sites, J. R.

    2009-01-01

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

  14. Charge density wave transition in single-layer titanium diselenide

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

    Chen, P.; Chan, Y. -H.; Fang, X. -Y.; Zhang, Y.; Chou, M. Y.; Mo, S. -K.; Hussain, Z.; Fedorov, A. -V.; Chiang, T. -C.

    2015-11-16

    A single molecular layer of titanium diselenide (TiSe2) is a promising material for advanced electronics beyond graphene--a strong focus of current research. Such molecular layers are at the quantum limit of device miniaturization and can show enhanced electronic effects not realizable in thick films. We show that single-layer TiSe2 exhibits a charge density wave (CDW) transition at critical temperature TC=232±5 K, which is higher than the bulk TC=200±5 K. Angle-resolved photoemission spectroscopy measurements reveal a small absolute bandgap at room temperature, which grows wider with decreasing temperature T below TC in conjunction with the emergence of (2 × 2) ordering.more » The results are rationalized in terms of first-principles calculations, symmetry breaking and phonon entropy effects. The behavior of the Bardeen-Cooper-Schrieffer (BCS) gap implies a mean-field CDW order in the single layer and an anisotropic CDW order in the bulk.« less

  15. Charge density wave transition in single-layer titanium diselenide

    SciTech Connect (OSTI)

    Chen, P.; Chan, Y. -H.; Fang, X. -Y.; Zhang, Y.; Chou, M. Y.; Mo, S. -K.; Hussain, Z.; Fedorov, A. -V.; Chiang, T. -C.

    2015-11-16

    A single molecular layer of titanium diselenide (TiSe2) is a promising material for advanced electronics beyond graphene--a strong focus of current research. Such molecular layers are at the quantum limit of device miniaturization and can show enhanced electronic effects not realizable in thick films. We show that single-layer TiSe2 exhibits a charge density wave (CDW) transition at critical temperature TC=232±5 K, which is higher than the bulk TC=200±5 K. Angle-resolved photoemission spectroscopy measurements reveal a small absolute bandgap at room temperature, which grows wider with decreasing temperature T below TC in conjunction with the emergence of (2 × 2) ordering. The results are rationalized in terms of first-principles calculations, symmetry breaking and phonon entropy effects. The behavior of the Bardeen-Cooper-Schrieffer (BCS) gap implies a mean-field CDW order in the single layer and an anisotropic CDW order in the bulk.

  16. Gallium nitride nanotube lasers

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

    Li, Changyi; Liu, Sheng; Hurtado, Antonio; Wright, Jeremy Benjamin; Xu, Huiwen; Luk, Ting Shan; Figiel, Jeffrey J.; Brener, Igal; Brueck, Steven R. J.; Wang, George T.

    2015-01-01

    Lasing is demonstrated from gallium nitride nanotubes fabricated using a two-step top-down technique. By optically pumping, we observed characteristics of lasing: a clear threshold, a narrow spectral, and guided emission from the nanotubes. In addition, annular lasing emission from the GaN nanotube is also observed, indicating that cross-sectional shape control can be employed to manipulate the properties of nanolasers. The nanotube lasers could be of interest for optical nanofluidic applications or application benefitting from a hollow beam shape.

  17. Cost and Potential of Monolithic CIGS Photovoltaic Modules

    SciTech Connect (OSTI)

    Horowitz, Kelsey A.; Woodhouse, Michael

    2015-06-14

    A bottom-up cost analysis of monolithic, glass-glass Cu(In,Ga)(Se,S)2 (CIGS) modules is presented, illuminating current cost drivers for this technology and possible pathways to reduced cost. At 14% module efficiency, for the case of U.S. manufacturing, a manufacturing cost of $0.56/WDC and a minimum sustainable price of $0.72/WDC were calculated. Potential for reduction in manufacturing costs to below $0.40/WDC in the long-term may be possible if module efficiency can be increased without significant increase in $/m2 costs. The levelized cost of energy (LCOE) in Phoenix, AZ under different conditions is assessed and compared to standard c-Si.

  18. Cost and Potential of Monolithic CIGS Photovoltaic Modules

    SciTech Connect (OSTI)

    Horowitz, Kelsey; Woodhouse, Michael

    2015-06-17

    A bottom-up cost analysis of monolithic, glass-glass Cu(In,Ga)(Se,S)2 (CIGS) modules is presented, illuminating current cost drivers for this technology and possible pathways to reduced cost. At 14% module efficiency, for the case of U.S. manufacturing, a manufacturing cost of $0.56/WDC and a minimum sustainable price of $0.72/WDC were calculated. Potential for reduction in manufacturing costs to below $0.40/WDC in the long-term may be possible if module efficiency can be increased without significant increase in $/m2 costs. The levelized cost of energy (LCOE) in Phoenix, AZ under different conditions is assessed and compared to standard c-Si.

  19. Study on the Humidity Susceptibility of Thin-Film CIGS Absorber

    SciTech Connect (OSTI)

    Pern, F. J.; Egaas, B.; To, B.; Jiang, C. S.; Li, J. V.; Glynn, S.; DeHart, C.

    2010-01-01

    The report summarizes the research on the susceptibility of a thermally co-evaporated CuInGaSe2 (CIGS) thin-film absorber to humidity and its consequence on composition, morphology, electrical and electronic properties, and device efficiency.

  20. Flexible CIGS Test and Evaluation: Cooperative Research and Development Final Report, CRADA Number CRD-08-293

    SciTech Connect (OSTI)

    Kempe, M.

    2015-03-01

    NREL will assist 3M in evaluating the application of 3M encapsulant materials on industry-supplied, flexible CIGS minimodules.

  1. Sodium-Doped Molybdenum Targets for Controllable Sodium Incorporation in CIGS Solar Cells

    SciTech Connect (OSTI)

    Mansfield, L. M.; Repins, I. L.; Glynn, S.; Carducci, M. D.; Honecker, D. M.; Pankow, J.l W.; Young, M. R.; DeHart, C.; Sundaramoorthy, R.; Beall, C. L.; To, B.

    2011-01-01

    The efficiency of Cu(In, Ga)Se{sub 2} (CIGS) solar cells is enhanced when Na is incorporated in the CIGS absorber layer. This work examines Na incorporation in CIGS utilizing Na-doped Mo sputtered from targets made with sodium molybdate-doped (MONA) powder. Mo:Na films with varying thicknesses were sputtered onto Mo-coated borosilicate glass (BSG) or stainless steel substrates for CIGS solar cells. By use of this technique, the Na content of CIGS can be varied from near-zero to higher than that obtained from a soda-lime glass (SLG) substrate. Targets and deposition conditions are described. The doped Mo films are analyzed, and the resulting devices are compared to devices fabricated on Mo-coated SLG as well as Mo-coated BSG with NaF. Completed devices utilizing MONA exceeded 15.7% efficiency without anti-reflective coating, which was consistently higher than devices prepared with the NaF precursor. Strategies for minimizing adhesion difficulties are presented.

  2. Sodium-Doped Molybdenum Targets for Controllable Sodium Incorporation in CIGS Solar Cells: Preprint

    SciTech Connect (OSTI)

    Mansfield, L. M.; Repins, I. L.; Glynn, S.; Carducci, M. D.; Honecker, D. M.; Pankow, J.; Young, M.; DeHart, C.; Sundaramoorthy, R.; Beall, C. L.; To, B.

    2011-07-01

    The efficiency of Cu(In,Ga)Se2 (CIGS) solar cells is enhanced when Na is incorporated in the CIGS absorber layer. This work examines Na incorporation in CIGS utilizing Na-doped Mo sputtered from targets made with sodium molybdate-doped (MONA) powder. Mo:Na films with varying thicknesses were sputtered onto Mo-coated borosilicate glass (BSG) or stainless steel substrates for CIGS solar cells. By use of this technique, the Na content of CIGS can be varied from near-zero to higher than that obtained from a soda-lime glass (SLG) substrate. Targets and deposition conditions are described. The doped Mo films are analyzed, and the resulting devices are compared to devices fabricated on Mo-coated SLG as well as Mo-coated BSG with NaF. Completed devices utilizing MONA exceeded 15.7% efficiency without anti-reflective coating, which was consistently higher than devices prepared with the NaF precursor. Strategies for minimizing adhesion difficulties are presented.

  3. 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.

    2012-10-01

    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.

  4. 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.

    1997-10-01

    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.

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

    DOE Patents [OSTI]

    Eser, Erten; Fields, Shannon

    2012-05-01

    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.

  6. Overview and Challenges of Thin Film Solar Electric Technologies

    SciTech Connect (OSTI)

    Ullal, H. S.

    2008-12-01

    In this paper, we report on the significant progress made worldwide by thin-film solar cells, namely, amorphous silicon (a-Si), cadmium telluride (CdTe), and copper indium gallium diselenide (CIGS). Thin-film photovoltaic (PV) technology status is also discussed in detail. In addition, R&D and technology challenges in all three areas are elucidated. The worldwide estimated projection for thin-film PV technology production capacity announcements are estimated at more than 5000 MW by 2010.

  7. P-type gallium nitride

    DOE Patents [OSTI]

    Rubin, Michael; Newman, Nathan; Fu, Tracy; Ross, Jennifer; Chan, James

    1997-01-01

    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.

  8. P-type gallium nitride

    DOE Patents [OSTI]

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

    1997-08-12

    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.

  9. Colloidal CIGS and CZTS nanocrystals: A precursor route to printed photovoltaics

    SciTech Connect (OSTI)

    Akhavan, Vahid A.; Goodfellow, Brian W.; Panthani, Matthew G.; Steinhagen, Chet; Harvey, Taylor B.; Stolle, C. Jackson; Korgel, Brian A.

    2012-05-15

    This review article summarizes our research focused on Cu(In{sub 1-x}Ga{sub x})Se{sub 2} (CIGS) nanocrystals, including their synthesis and implementation as the active light absorbing material in photovoltaic devices (PVs). CIGS PV layers are typically made using a high temperature (>450 Degree-Sign C) process in which Cu, In and Ga are sequentially or co-evaporated and selenized. We have sought to use CIGS nanocrystals synthesized with the desired stoichiometry to deposit PV device layers without high temperature processing. This approach, using spray deposition of the CIGS light absorber layers, without high temperature selenization, has enabled up to 3.1% power conversion efficiency under AM 1.5 solar illumination. Although the device efficiency is too low for commercialization, these devices provide a proof-of-concept that solution-deposited CIGS nanocrystal films can function in PV devices, enabling unconventional device architectures and materials combinations, including the use of flexible, inexpensive and light-weight plastic substrates. - Graphical abstract: The semiconductor light-absorbing layers in photovoltaic devices can be deposited under ambient conditions using nanocrystal inks. Devices can be fabricated on glass or on mechanically flexible plastic substrates. Highlights: Black-Right-Pointing-Pointer CIGS and CZTS nanocrystals are synthesized and formulated into inks. Black-Right-Pointing-Pointer Nanocrystal films are spray deposited and used as light absorbing layers in photovoltaic devices. Black-Right-Pointing-Pointer Photovoltaic devices were constructed from nanowire mats. Black-Right-Pointing-Pointer Photovoltaic device efficiency is limited by electrical transport in the nanocrystal layers.

  10. Unusual Capacitance Emission Transients in CIGS Caused by Large Defect Entropy Changes

    SciTech Connect (OSTI)

    Young, D. L.; Ramanathan, K.; Crandall, R. S.

    2005-02-01

    Capacitance transient data from bias-pulse experiments on CdS/CIGS solar cells show an unusual behavior at high temperatures. Above 350 K, a minority-carrier trap, with a larger activation energy than a majority-carrier trap, emits faster than the lower activation-energy minority trap. A simple enthalpy model for trap emission cannot explain this counterintuitive behavior; but the more complete Gibbs free-energy model that includes entropy can explain it. We show that entropy plays a major role in carrier emission from traps in CIGS.

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

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

    Accomplishments (Conference) | SciTech Connect CIGS Thin-Film Solar Cell Research at NREL: FY04 Results and Accomplishments Citation Details In-Document Search Title: CIGS Thin-Film Solar Cell Research at NREL: FY04 Results and Accomplishments × You are accessing a document from the Department of Energy's (DOE) SciTech Connect. This site is a product of DOE's Office of Scientific and Technical Information (OSTI) and is provided as a public service. Visit OSTI to utilize additional

  12. Waste reduction options for manufacturers of copper indium diselenide photovoltaic cells

    SciTech Connect (OSTI)

    DePhillips, M.P.; Fthenakis, V.M.; Moskowitz, P.D.

    1994-03-01

    This paper identifies general waste reduction concepts and specific waste reduction options to be used in the production of copper indium diselenide (CIS) photovoltaic cells. A general discussion of manufacturing processes used for the production of photovoltaic cells is followed by a description of the US Environmental Protection Agency (EPA) guidelines for waste reduction (i.e., waste minimization through pollution prevention). A more specific discussion of manufacturing CIS cells is accompanied by detailed suggestions regarding waste minimization options for both inputs and outputs for ten stages of this process. Waste reduction from inputs focuses on source reduction and process changes, and reduction from outputs focuses on material reuse and recycling.

  13. Cost and Reliability Improvement for CIGS-Based PV on Flexible Substrate: Annual Technical Report, 24 May 2006 - 25 September 2007

    SciTech Connect (OSTI)

    Weideman, S.

    2008-08-01

    Global Solar Energy has enhanced module reliability, reduced cost and improved performance of its CIGS deposition process, and reduced cost of materials and processes for contacts.

  14. Atomically Thin Heterostructures Based on Single-Layer Tungsten Diselenide and Graphene [Plus Supplemental Information

    SciTech Connect (OSTI)

    Lin, Yu-Chuan; Chang, Chih-Yuan S.; Ghosh, Ram Krishna; Li, Jie; Zhu, Hui; Addou, Rafik; Diaconescu, Bogdan; Ohta, Taisuke; Peng, Xin; Lu, Ning; Kim, Moon J.; Robinson, Jeremy T.; Wallace, Robert M.; Mayer, Theresa S.; Datta, Suman; Li, Lain-Jong; Robinson, Joshua A.

    2014-11-10

    Heterogeneous engineering of two-dimensional layered materials, including metallic graphene and semiconducting transition metal dichalcogenides, presents an exciting opportunity to produce highly tunable electronic and optoelectronic systems. We report the direct growth of highly crystalline, monolayer tungsten diselenide (WSe2) on epitaxial graphene (EG). Raman spectroscopy and photoluminescence confirms high-quality WSe2 monolayers; while transmission electron microscopy shows an atomically sharp interface and low energy electron diffraction confirms near perfect orientation between WSe2 and EG. Vertical transport measurements across the WSe2/EG heterostructure provides evidence that a tunnel barrier exists due to the van der Waals gap, and is supported by density functional theory that predicts a 1.6 eV barrier for transport from WSe2 to graphene.

  15. Atomically Thin Heterostructures Based on Single-Layer Tungsten Diselenide and Graphene [Plus Supplemental Information

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

    Lin, Yu-Chuan; Chang, Chih-Yuan S.; Ghosh, Ram Krishna; Li, Jie; Zhu, Hui; Addou, Rafik; Diaconescu, Bogdan; Ohta, Taisuke; Peng, Xin; Lu, Ning; et al

    2014-11-10

    Heterogeneous engineering of two-dimensional layered materials, including metallic graphene and semiconducting transition metal dichalcogenides, presents an exciting opportunity to produce highly tunable electronic and optoelectronic systems. We report the direct growth of highly crystalline, monolayer tungsten diselenide (WSe2) on epitaxial graphene (EG). Raman spectroscopy and photoluminescence confirms high-quality WSe2 monolayers; while transmission electron microscopy shows an atomically sharp interface and low energy electron diffraction confirms near perfect orientation between WSe2 and EG. Vertical transport measurements across the WSe2/EG heterostructure provides evidence that a tunnel barrier exists due to the van der Waals gap, and is supported by density functional theorymore » that predicts a 1.6 eV barrier for transport from WSe2 to graphene.« less

  16. Gallium arsenide recycle chemistry and metallurgy

    SciTech Connect (OSTI)

    Bartlett, R.W.

    1987-03-23

    Research was successfully conducted on a smelting approach to separate gallium from arsenic using a liquid copper alloy to collect arsenic while oxidizing the gallium into a soda-silica slag. The slag and copper form two immiscible liquid phases. With GaAs in powder form, smelting at 1150 to 1220{degree}C yields 98% of the gallium in the slag and at least 96% of the arsenic in the copper. The gallium concentration in this slag is, relative to other sources, very high, and it can be processed further to obtain crude gallium. The effect of chemical oxidizers on arsenic and gallium distribution between slag and copper was determined. The solidified copper-arsenic alloy is environmentally inert. However, any precious metals present with the electronic scrap will nearly completely collect in the copper. Commercial copper refineries are capable of recovering precious metals from the copper-arsenic alloy, and are equipped to handle large amounts of arsenic when compared with the amount of arsenic used in GaAs devices, even with many fold future expansions.

  17. Generator for gallium-68 and compositions obtained therefrom

    DOE Patents [OSTI]

    Neirinckx, Rudi D. (Medfield, MA); Davis, Michael A. (Westwood, MA)

    1981-01-01

    A generator for obtaining radioactive gallium-68 from germanium-68 bound in a resin containing unsubstituted phenolic hydroxyl groups. The germanium-68 is loaded into the resin from an aqueous solution of the germanium-68. A physiologically acceptable solution of gallium-68 having an activity of 0.1 to 50 millicuries per milliliter of gallium-68 solution is obtained. The solution is obtained from the bound germanium-68 which forms gallium-68 in situ by eluting the column with a hydrochloric acid solution to form an acidic solution of gallium-68. The acidic solution of gallium-68 can be neutralized.

  18. Rapid and Nondestructive Identification of Polytypism and Stacking Sequences in Few-Layer Molybdenum Diselenide by Raman Spectroscopy

    SciTech Connect (OSTI)

    Lu, Xin; Utama, M. Iqbal Bakti; Lin, Junhao; Luo, Xin; Zhao, Yanyuan; Zhang, Jun; Pantelides, Sokrates T.; Zhou, Wu; Quek, Su Ying; Xiong, Qihua

    2015-07-02

    Various combinations of interlayer shear modes emerge in few-layer molybdenum diselenide grown by chemical vapor deposition depending on the stacking configuration of the sample. Raman measurements may also reveal polytypism and stacking faults, as supported by first principles calculations and high-resolution transmission electron microscopy. Thus, Raman spectroscopy is an important tool in probing stacking-dependent properties in few-layer 2D materials.

  19. BES Web Highlight: Single-mode gallium nitride nanowire lasers

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

    Web Highlight: Single-mode gallium nitride nanowire lasers - Sandia Energy Energy Search ... Twitter Google + Vimeo GovDelivery SlideShare BES Web Highlight: Single-mode gallium ...

  20. 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)

    Thin Film CIGS and CdTe Photovoltaic Technologies: Commercialization, Critical Issues, and Applications Preprint H.S. Ullal and B. von Roedern To be presented at the 22nd European Photovoltaic Solar Energy Conference (PVSEC) and Exhibition Milan, Italy September 3-7, 2007 Conference Paper NREL/CP-520-42058 September 2007 NREL is operated by Midwest Research Institute ● Battelle Contract No. DE-AC36-99-GO10337 NOTICE The submitted manuscript has been offered by an employee of the Midwest

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

    SciTech Connect (OSTI)

    Woods, L.

    2011-04-01

    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.

  2. Gallium nitride junction field-effect transistor

    DOE Patents [OSTI]

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

    1999-02-02

    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.

  3. Gallium nitride junction field-effect transistor

    DOE Patents [OSTI]

    Zolper, John C.; Shul, Randy J.

    1999-01-01

    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.

  4. Solar cell with a gallium nitride electrode

    DOE Patents [OSTI]

    Pankove, Jacques I.

    1979-01-01

    A solar cell which comprises a body of silicon having a P-N junction therein with a transparent conducting N-type gallium nitride layer as an ohmic contact on the N-type side of the semiconductor exposed to solar radiation.

  5. 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.

    2010-10-01

    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.

  6. Final Report- High throughput CIGS solar cell fabrication via ultra-thin absorber layer with optical confinement and (Cd, CBD)- free heterojunction partner

    Broader source: Energy.gov [DOE]

    The main objective of this proposal was to use several pathways to reduce the production cost of CIGS PV modules and therefore the levelized cost of energy (LCOE) associated with this technology.

  7. Photovoltaic manufacturing cost and throughput improvements for thin-film CIGS-based modules: Phase 1 technical report, July 1998--July 1999

    SciTech Connect (OSTI)

    Wiedeman, S.; Wendt, R.G.

    2000-03-01

    The primary objectives of the Global Solar Energy (GSE) Photovoltaic Manufacturing Technology (PVMaT) subcontract are directed toward reducing cost and expanding the production rate of thin-film CuInGaSe{sub 2} (CIGS)-based PV modules on flexible substrates. Improvements will be implemented in monolithic integration, CIGS deposition, contact deposition, and in-situ CIGS control and monitoring. In Phase 1, GSE has successfully attacked many of the highest risk aspects of each task. All-laser, selective scribing processes for CIGS have been developed, and many end-of-contract goals for scribing speed have been exceeded in the first year. High-speed ink-jet deposition of insulating material in the scribes now appears to be a viable technique, again exceeding some end-of-contract goals in the first year. Absorber deposition of CIGS was reduced corresponding to throughput speeds of up to 24-in/min, also exceeding an end-of-contract goal. Alternate back-contact materials have been identified that show potential as candidates for replacement of higher-cost molybdenum, and a novel, real-time monitoring technique (parallel-detector spectroscopic ellipsometry) has shown remarkable sensitivity to relevant properties of the CIGS absorber layer for use as a diagnostic tool. Currently, one of the bilayers has been baselined by GSE for flexible CIGS on polymeric substrates. Resultant back-contacts meet sheet-resistance goals and exhibit much less intrinsic stress than Mo. CIGS has been deposited, and resultant devices are comparable in performance to pure Mo back-contacts. Debris in the chamber has been substantially reduced, allowing longer roll-length between system cleaning.

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

    SciTech Connect (OSTI)

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

    2008-05-01

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

  9. High intensity x-ray source using liquid gallium target

    DOE Patents [OSTI]

    Smither, Robert K.; Knapp, Gordon S.; Westbrook, Edwin M.; Forster, George A.

    1990-01-01

    A high intensity x-ray source that uses a flowing stream of liquid gallium as a target with the electron beam impinging directly on the liquid metal.

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

    Broader source: Energy.gov [DOE]

    This project is producing high-efficiency semipolar light-emitting diodes (LEDs) on low-defect bulk gallium nitride (GaN) substrates.

  11. 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.

    2012-10-01

    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 μm to 0.50 μm 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

  12. Systems and methods for solar cells with CIS and CIGS films made by reacting evaporated copper chlorides with selenium

    SciTech Connect (OSTI)

    Albin, David S.; Noufi, Rommel

    2015-06-09

    Systems and methods for solar cells with CIS and CIGS films made by reacting evaporated copper chlorides with selenium are provided. In one embodiment, a method for fabricating a thin film device comprises: providing a semiconductor film comprising indium (In) and selenium (Se) upon a substrate; heating the substrate and the semiconductor film to a desired temperature; and performing a mass transport through vapor transport of a copper chloride vapor and se vapor to the semiconductor film within a reaction chamber.

  13. Recent developments in high-efficiency PV cells

    SciTech Connect (OSTI)

    Deb, S.

    2000-05-22

    Enormous progress has been made in recent years on a number of photovoltaic (PV) materials and devices in terms of conversion efficiencies. Ultrahigh-efficiency (>30{percent}) PV cells have been fabricated from gallium arsenide (GaAs) and its ternary alloys such as gallium indium phosphide (GaInP{sub 2}). The high-efficiency GaAs-based solar cells are being produced on a commercial scale, particularly for space applications. Efficiencies in the range of 18{percent} to 24{percent} have been achieved in traditional silicon-based devices fabricated from both multicrystalline and single-crystal materials. Major advances in efficiency have also been made on various thin-film solar cells based on amorphous silicon (aSi:H), copper gallium indium diselenide (CIGS), and cadmium telluride materials. This paper gives a brief overview of the recent progress in PV cell efficiencies based on these materials and devices.

  14. Laser photochemistry of gallium-containing compounds. [Trimethylgallium

    SciTech Connect (OSTI)

    Baughcum, S.L.; Oldenborg, R.C.

    1986-01-01

    The production of gas-phase gallium atoms in the photolysis of trimethylgallium has been investigated at 193 nm and at other laser wavelengths. Ground state (4 /sup 2/P/sup 0//sub 1/2) and metastable (4 /sup 2/P/sup 0//sub 3/2/) gallium atoms are detected using laser-induced fluorescence techniques. Our results indicate that gallium atoms continue to be produced at long times after the laser pulse. The observed dependence on photolysis laser fluence, trimethylgallium pressure, and buffer gas pressure are consistent with a mechanism in which highly excited gallium methyl radicals undergo unimolecular decomposition to produce gallium atoms. Since this process is observed to happen on the time scale of hundreds of microseconds, these results have important implications for studies of metal deposition and direct laser writing by laser photolysis of organometallic compounds. 31 refs., 5 figs.

  15. Compatibility of ITER candidate structural materials with static gallium

    SciTech Connect (OSTI)

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

    1993-12-01

    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.

  16. High-Efficiency CdTe and CIGS Thin-Film Solar Cells: Highlights and Challenges; Preprint

    SciTech Connect (OSTI)

    Noufi, R.; Zweibel, K.

    2006-05-01

    Thin-film photovoltaic (PV) modules of CdTe and Cu(In,Ga)Se2 (CIGS) have the potential to reach cost-effective PV-generated electricity. These technologies have transitioned from the laboratory to the market place. Pilot production and first-time manufacturing are ramping up to higher capacity and enjoying a flood of venture-capital funding. CIGS solar cells and modules have achieved 19.5% and 13% efficiencies, respectively. Likewise, CdTe cells and modules have reached 16.5% and 10.2% efficiencies, respectively. Even higher efficiencies from the laboratory and from the manufacturing line are only a matter of time. Manufacturing-line yield continues to improve and is surpassing 85%. Long-term stability has been demonstrated for both technologies; however, some failures in the field have also been observed, emphasizing the critical need for understanding degradation mechanisms and packaging options. The long-term potential of the two technologies require R&D emphasis on science and engineering-based challenges to find solutions to achieve targeted cost-effective module performance, and in-field durability. Some of the challenges are common to both, e.g., in-situ process control and diagnostics, thinner absorber, understanding degradation mechanisms, protection from water vapor, and innovation in high-speed processing and module design. Other topics are specific to the technology, such as lower-cost and fast-deposition processes for CIGS, and improved back contact and voltage for CdTe devices.

  17. Interactions of Zircaloy Cladding with Gallium: Final Report

    SciTech Connect (OSTI)

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

    1998-09-01

    The U.S. Department of Energy has established a dual-track approach to the disposition of plutonium arising from the dismantling of nuclear weapons. Both immobilization and reactor-based mixed-oxide (MOX) fuel technologies are being evaluated. The reactor-based MOX fuel option requires assessment of the potential impact of concentrations of gallium (on the order of 1 to 10 ppm), not present in conventional MOX fhel, on cladding material performance. Three previous repmts"3 identified several compatibility issues relating to the presence of gallium in MOX fuel and its possible reaction with fiel cladding. Gallium initially present in weapons-grade (WG) plutonium is largely removed during processing to produce MOX fhel. After blending the plutonium with uranium, only 1 to 10 ppm gallium is expected in the sintered MOX fuel. Gallium present as gallium oxide (G~OJ could be evolved as the suboxide (G~O). Migration of the evolved G~O and diffusion of gallium in the MOX matrix along thermal gradients could lead to locally higher concentrations of G~03. Thus, while an extremely low concentration of gallium in MOX fiel almost ensures a lack of significant interaction of gallium whh Zircaloy fhel cladding, there remains a small probability that corrosion effects will not be negligible. General corrosion in the form of surface alloying resulting from formation of intermetallic compounds between Zircaloy and gallium should be ma& limited and, therefore, superficial because of the expected low ratio of gallium to the surface area or volume of the Zircaloy cladding. Although the expected concentration of gallium is low and there is very limited volubility of gallium in zirconium, especially at temperatures below 700 "C,4 grain boundary penetration and liquid metal embrittlement (LME) are forms of localized corrosion that were also considered. One fuel system darnage mechanism, pellet clad interaction, has led to some failure of the Zircaloy cladding in light-water reactors (LWRS

  18. Cavity optomechanics in gallium phosphide microdisks

    SciTech Connect (OSTI)

    Mitchell, Matthew; Barclay, Paul E.; Hryciw, Aaron C.

    2014-04-07

    We demonstrate gallium phosphide (GaP) microdisk optical cavities with intrinsic quality factors >2.8??10{sup 5} and mode volumes <10(?/n){sup 3}, and study their nonlinear and optomechanical properties. For optical intensities up to 8.0??10{sup 4} intracavity photons, we observe optical loss in the microcavity to decrease with increasing intensity, indicating that saturable absorption sites are present in the GaP material, and that two-photon absorption is not significant. We observe optomechanical coupling between optical modes of the microdisk around 1.5??m and several mechanical resonances, and measure an optical spring effect consistent with a theoretically predicted optomechanical coupling rate g{sub 0}/2??30?kHz for the fundamental mechanical radial breathing mode at 488?MHz.

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

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

    Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers Print Wednesday, 21 December 2005 00:00 Low-dimensional materials have gained much attention not only because of the nonstop march toward miniaturization in the electronics industry but also for the exotic properties that are inherent in their small size. One approach for creating low-dimensional structures is to exploit the nanoscale or atomic-scale features

  20. Generator for ionic gallium-68 based on column chromatography

    DOE Patents [OSTI]

    Neirinckx, Rudi D.; Davis, Michael A.

    1981-01-01

    A physiologically acceptable solution of gallium-68 fluorides, having an activity of 0.1 to 50 millicuries per milliliter of solution is provided. The solution is obtained from a generator comprising germanium-68 hexafluoride bound to a column of an anion exchange resin which forms gallium-68 in situ by eluting the column with an acid solution to form a solution containing .sup.68 Ga-fluorides. The solution then is neutralized prior to administration.

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

    SciTech Connect (OSTI)

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

    2008-05-01

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

  2. 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.; Munoz-Mateos, J. C.; Gil de Paz, A.; Verley, S.; Leon, S.

    2011-07-20

    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.

  3. 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.

    1990-12-01

    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.

  4. Gallium Safety in the Laboratory INEEL/CON-03-00078

    Office of Scientific and Technical Information (OSTI)

    ... 1987, pp. 411-418. 27. F. F. Hahn, R. K. Wolff, and R. F. Henderson, "Gallium Oxide ... Institute, December 1987. 28. R. K. Wolff et al., "Toxicity of Gallium Oxide ...

  5. Gallium based low-interaction anions

    DOE Patents [OSTI]

    King, Wayne A.; Kubas, Gregory J.

    2000-01-01

    The present invention provides: a composition of the formula M.sup.+x (Ga(Y).sub.4.sup.-).sub.x where M is a metal selected from the group consisting of lithium, sodium, potassium, cesium, calcium, strontium, thallium, and silver, x is an integer selected from the group consisting of 1 or 2, each Y is a ligand selected from the group consisting of aryl, alkyl, hydride and halide with the proviso that at least one Y is a ligand selected from the group consisting of aryl, alkyl and halide; a composition of the formula (R).sub.x Q.sup.+ Ga(Y).sub.4.sup.- where Q is selected from the group consisting of carbon, nitrogen, sulfur, phosphorus and oxygen, each R is a ligand selected from the group consisting of alkyl, aryl, and hydrogen, x is an integer selected from the group consisting of 3 and 4 depending upon Q, and each Y is a ligand selected from the group consisting of aryl, alkyl, hydride and halide with the proviso that at least one Y is a ligand selected from the group consisting of aryl, alkyl and halide; an ionic polymerization catalyst composition including an active cationic portion and a gallium based weakly coordinating anion; and bridged anion species of the formula M.sup.+x.sub.y [X(Ga(Y.sub.3).sub.z ].sup.-y.sub.x where M is a metal selected from the group consisting of lithium, sodium, potassium, magnesium, cesium, calcium, strontium, thallium, and silver, x is an integer selected from the group consisting of 1 or 2, X is a bridging group between two gallium atoms, y is an integer selected from the group consisting 1 and 2, z is an integer of at least 2, each Y is a ligand selected from the group consisting of aryl, alkyl, hydride and halide with the proviso that at least one Y is a ligand selected from the group consisting of aryl, alkyl and halide.

  6. Pure silver ohmic contacts to N- and P- type gallium arsenide materials

    DOE Patents [OSTI]

    Hogan, Stephen J.

    1986-01-01

    Disclosed is an improved process for manufacturing gallium arsenide semiconductor devices having as its components an 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 diffused layer and the substrate layer, wherein the n-type layer comprises a substantially low doping carrier concentration.

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

    DOE Patents [OSTI]

    Hogan, S.J.

    1983-03-13

    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.

  8. First results from the Soviet-American Gallium Experiment

    SciTech Connect (OSTI)

    Abazov, A.I.; Abdurashitov, D.N.; Anosov, O.L.; Eroshkina, L.A.; Faizov, E.L.; Gavrin, V.N.; Kalikhov, A.V.; Knodel, T.V.; Knyshenko, I.I.; Kornoukhov, V.N.; Mezentseva, S.A.; Mirmov, I.N.; Ostrinsky, A.I.; Petukhov, V.V.; Pshukov, A.M.; Revzin, N.Y.; Shikhin, A.A.; Timofeyev, P.V.; Veretenkin, E.P.; Vermul, V.M.; Zakharov, Y.; Zatsepin, G.T.; Zhandarov, V.I. . Inst. Yadernykh Issledovanij); Bowl

    1990-01-01

    The Soviet-American Gallium Experiment is the first experiment able to measure the dominant flux of low energy p-p solar neutrinos. Four extractions made during January to May 1990 from 30 tons of gallium have been counted and indicate that the flux is consistent with 0 SNU and is less than 72 SNU (68% CL) and less than 138 SNU (95% CL). This is to be compared with the flux of 132 SNU predicted by the Standard Solar Model. 10 refs., 4 figs., 1 tab.

  9. 03.01.16 RH Nickel-Gallium - JCAP

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

    CO2 electrochemical reduction catalyzed by bimetallic materials at low overpotential Torelli, D. A., Francis, S.A. et al. Nickel-Gallium-Catalyzed Electrochemical Reduction of CO2 to Highly Reduced Products at Low Overpotentials. ACS Catalysis, 6, 2100-2104, DOI: 10.1021/acscatal.5b02888 (2016). Scientific Achievement Electrocatalytic reduction of CO2 to highly reduced C2 (ethylene and ethane) and C1 (methane) products was accomplished on three different phases of nickel-gallium films at low

  10. Compatibility of ITER candidate materials with static gallium

    SciTech Connect (OSTI)

    Luebbers, P.R.; Chopra, O.K.

    1995-09-01

    Corrosion tests have been conducted to determine the compatibility of gallium with candidate structural materials for the International Thermonuclear Experimental Reactor (ITER) first wall/blanket systems, e.g., Type 316 stainless steel (SS), Inconel 625, and Nb-5 Mo-1 Zr. The results indicate that Type 316 SS is least resistant to corrosion in static gallium and Nb-5 Mo-1 Zr alloy is most resistant. At 400 C, corrosion rates for Type 316 SS, Inconel 625, and Nb-5 Mo-1 Zr alloy are {approx} 4.0, 0.5, and 0.03 mm/yr, respectively. Iron, nickel, and chromium react rapidly with gallium. Iron shows greater corrosion than nickel at 400 C ({ge} 88 and 18 mm/yr, respectively). The present study indicates that at temperatures up to 400 C, corrosion occurs primarily by dissolution and is accompanied by formation of metal/gallium intermetallic compounds. The growth of intermetallic compounds may control the overall rate of corrosion.

  11. Evolution of Electronic Properties of (Cu(In,Ga)Se2 (CIGS)-Based Solar Cells During a 3-Stage Growth Process: Preprint

    SciTech Connect (OSTI)

    AbuShama, J. A.; Johnston, S.; Ahrenkiel, R.; Crandall, R.; Young, D.; Noufi, R.

    2003-04-01

    We investigated the electronic properties of ZnO/CdS/CIGS /Mo/SLG polycrystalline thin-film solar cells with compositions ranging from Cu-rich to In(Ga)-rich by deep-level transient spectroscopy (DLTS) and capacitance-voltage (C-V) measurements. This compositional change represents the evolution of the film during growth by the 3-stage process. Two sets (four samples each) of CIGS thin films were prepared with Ga/(In+Ga) ratios of~0.3 (low Ga) and~0.6 (high Ga). The Cu/(In+Ga) ratio ranges from 1.24 (Cu-rich) to 0.88 (In(Ga)-rich). The films were treated with NaCN to remove the Cu2-xSe phase where needed. Key results include: (1) For low-Ga devices, DLTS data show that acceptor-like traps dominate in samples where CIGS grains do not go through the Cu-rich to In(Ga)-rich transition, whereas donor-like traps dominate in In(Ga)-rich samples. Therefore, we see a clear transformation of defects from acceptor-like to donor-like traps. The activation energies of these traps range from 0.12 to 0.63 eV. We also observed that NaCN treatment eliminates a deep minority trap in the In(Ga)-rich devices, (2) For high-Ga devices, only majority-carrier traps were detected. These traps again range from shallow to deep, (3) The carrier concentration around the junction and the density of traps decrease as the CIGS becomes more In(Ga)-rich.

  12. Tolerance of Three-Stage CIGS Deposition to Variations Imposed by Roll-to-Roll Processing: Final Technical Report, May 2003 - September 2005

    SciTech Connect (OSTI)

    Beck, M. E.; Britt, J. S.

    2006-01-01

    Three-stage co-evaporation of CIGS imposes stringent limits on the parameter space if high-efficient devices are to result. Substrate temperatures during the 1st stage (as well as during the 2nd and 3rd stage), Se partial pressure, and amount of Na supplied are critical for good nucleation, proper In-Ga-selenide precursor phase, and diffusion of Cu into the precursor, as well as diffusion of Ga through the film. In addition, the degree of Cu-rich excursion impacts maximum performance and process tolerance. Enveloping the above is the basic time-temperature profile inextricably linked to the metals delivery rates. Although high-efficiency, three-stage deposited CIGS devices on the R&D scale are grown at about 20-45 minutes to thicknesses of 2 to 2.5 m, the latter is not a viable approach for an economic manufacturing process. At Global Solar Energy, Inc., CIGS films are typically grown in about 6 minutes to thicknesses of less than 2 m. At the same time, the emissivity and thermal conductivity of stainless steel is vastly different from that of glass, and the reduced growth time poses restrictions on the substrate temperature ramp rates and diffusion of species (reaction kinetics). Material compatibility in the highly corrosive Se environment places limitations on the substrate heaters; i.e., substrate temperatures. Finally, one key advantage of a RTR deposition approach (compact equipment) restricts post CIGS Se exposure and cool-down rates to be vastly different than those practiced in the laboratory.

  13. Self- and zinc diffusion in gallium antimonide

    SciTech Connect (OSTI)

    Nicols, Samuel Piers

    2002-03-26

    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

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

    SciTech Connect (OSTI)

    Wiedeman, S.

    2011-05-01

    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.

  15. Application of the bounds-analysis approach to arsenic and gallium...

    Office of Scientific and Technical Information (OSTI)

    Details In-Document Search This content will become publicly available on January 23, 2016 Title: Application of the bounds-analysis approach to arsenic and gallium antisite...

  16. Gallium Safety in the Laboratory INEEL/CON-03-00078

    Office of Scientific and Technical Information (OSTI)

    or represents that its use by such third party would not infringe privately owned rights. ... gallium surfaces with oils from human skin, and gloves protect against puncture wounds. ...

  17. HIGH-QUALITY, LOW-COST BULK GALLIUM NITRIDE SUBSTRATES GROWN...

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

    by 60%, and energy for information technology infrastructure power delivery by 20%. High-Quality, Low-Cost Bulk Gallium Nitride Substrates (1009.69 KB) More Documents & ...

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

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

    Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers Print Low-dimensional materials have gained much attention not only because of the nonstop march toward miniaturization in the electronics industry but also for the exotic properties that are inherent in their small size. One approach for creating low-dimensional structures is to exploit the nanoscale or atomic-scale features that exist naturally in the three-dimensional (bulk) form of materials. By this means, a group from the

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

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

    Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers Print Low-dimensional materials have gained much attention not only because of the nonstop march toward miniaturization in the electronics industry but also for the exotic properties that are inherent in their small size. One approach for creating low-dimensional structures is to exploit the nanoscale or atomic-scale features that exist naturally in the three-dimensional (bulk) form of materials. By this means, a group from the

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

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

    Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers Print Low-dimensional materials have gained much attention not only because of the nonstop march toward miniaturization in the electronics industry but also for the exotic properties that are inherent in their small size. One approach for creating low-dimensional structures is to exploit the nanoscale or atomic-scale features that exist naturally in the three-dimensional (bulk) form of materials. By this means, a group from the

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

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

    Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers Print Low-dimensional materials have gained much attention not only because of the nonstop march toward miniaturization in the electronics industry but also for the exotic properties that are inherent in their small size. One approach for creating low-dimensional structures is to exploit the nanoscale or atomic-scale features that exist naturally in the three-dimensional (bulk) form of materials. By this means, a group from the

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

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

    Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers Print Low-dimensional materials have gained much attention not only because of the nonstop march toward miniaturization in the electronics industry but also for the exotic properties that are inherent in their small size. One approach for creating low-dimensional structures is to exploit the nanoscale or atomic-scale features that exist naturally in the three-dimensional (bulk) form of materials. By this means, a group from the

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

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

    Innovation Portal Vehicles and Fuels Vehicles and Fuels Building Energy Efficiency Building Energy Efficiency Find More Like This Return to Search Electrochemical Solution Growth: Gallium Nitride Crystal Growth Sandia National Laboratories Contact SNL About This Technology Publications: PDF Document Publication Market Sheet (886 KB) Technology Marketing SummarySandia National Laboratories has developed a disruptive new crystal growth technology, called Electrochemical Solution Growth (ESG).

  4. 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).

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

    DOE Patents [OSTI]

    Marks, Tobin J.; Chen, You-Xian

    2000-01-01

    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.

  6. Preliminary survey report: control technology for gallium arsenide processing at Morgan Semiconductor Division, Garland, Texas

    SciTech Connect (OSTI)

    Lenihan, K.L.

    1987-03-01

    The report covers a walk through survey made of the Morgan Semiconductor Facility in Garland, Texas, to evaluate control technology for gallium-arsenide dust in the semiconductor industry. Engineering controls included the synthesis of gallium-arsenide outside the crystal pullers to reduce arsenic residues in the pullers, also reducing worker exposure to arsenic during cleaning of the crystal pullers.

  7. Printed Module Interconnects

    SciTech Connect (OSTI)

    Stockert, Talysa R.; Fields, Jeremy D.; Pach, Gregory F.; Mauger, Scott A.; van Hest, Maikel F. A. M.

    2015-06-14

    Monolithic interconnects in photovoltaic modules connect adjacent cells in series, and are typically formed sequentially involving multiple deposition and scribing steps. Interconnect widths of 500 um every 10 mm result in 5% dead area, which does not contribute to power generation in an interconnected solar panel. This work expands on previous work that introduced an alternative interconnection method capable of producing interconnect widths less than 100 um. The interconnect is added to the module in a single step after deposition of the photovoltaic stack, eliminating the need for scribe alignment. This alternative method can be used for all types of thin film photovoltaic modules. Voltage addition with copper-indium-gallium-diselenide (CIGS) solar cells using a 2-scribe printed interconnect approach is demonstrated. Additionally, interconnect widths of 250 um are shown.

  8. Study on natural convection capability of liquid gallium for passive decay heat removal system (PDHRS)

    SciTech Connect (OSTI)

    Kang, S.; Ha, K. S.; Lee, S. W.; Park, S. D.; Kim, S. M.; Seo, H.; Kim, J. H.; Bang, I. C.

    2012-07-01

    The safety issues of the SFRs are important due to the fact that it uses sodium as a nuclear coolant, reacting vigorously with water and air. For that reason, there are efforts to seek for alternative candidates of liquid metal coolants having excellent heat transfer property and to adopt improved safety features to the SFR concepts. This study considers gallium as alternative liquid metal coolant applicable to safety features in terms of chemical activity issue of the sodium and aims to experimentally investigate the natural convection capability of gallium as a feasibility study for the development of gallium-based passive safety features in SFRs. In this paper, the design and construction of the liquid gallium natural convection loop were carried out. The experimental results of heat transfer coefficient of liquid gallium resulting in heat removal {approx}2.53 kW were compared with existing correlations and they were much lower than the correlations. To comparison of the experimental data with computer code analysis, gallium property code was developed for employing MARS-LMR (Korea version of RELAP) based on liquid gallium as working fluid. (authors)

  9. Electron transport in zinc-blende wurtzite biphasic gallium nitride nanowires and GaNFETs

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

    Jacobs, Benjamin W.; Ayres, Virginia M.; Stallcup, Richard E.; Hartman, Alan; Tupta, Mary Ann; Baczewski, Andrew David; Crimp, Martin A.; Halpern, Joshua B.; He, Maoqi; Shaw, Harry C.

    2007-10-19

    Two-point and four-point probe electrical measurements of a biphasic gallium nitride nanowire and current–voltage characteristics of a gallium nitride nanowire based field effect transistor are reported. The biphasic gallium nitride nanowires have a crystalline homostructure consisting of wurtzite and zinc-blende phases that grow simultaneously in the longitudinal direction. There is a sharp transition of one to a few atomic layers between each phase. Here, all measurements showed high current densities. Evidence of single-phase current transport in the biphasic nanowire structure is discussed.

  10. HIGH-QUALITY, LOW-COST BULK GALLIUM NITRIDE SUBSTRATES GROWN...

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

    Efficient manufacturing of gallium nitride (GaN) could reduce the cost of and improve the output for light-emitting diodes, solid-state lighting, laser displays, and other power ...

  11. Temperature dependence of carrier capture by defects in gallium arsenide

    SciTech Connect (OSTI)

    Wampler, William R.; Modine, Normand A.

    2015-08-01

    This report examines the temperature dependence of the capture rate of carriers by defects in gallium arsenide and compares two previously published theoretical treatments of this based on multi phonon emission (MPE). The objective is to reduce uncertainty in atomistic simulations of gain degradation in III-V HBTs from neutron irradiation. A major source of uncertainty in those simulations is poor knowledge of carrier capture rates, whose values can differ by several orders of magnitude between various defect types. Most of this variation is due to different dependence on temperature, which is closely related to the relaxation of the defect structure that occurs as a result of the change in charge state of the defect. The uncertainty in capture rate can therefore be greatly reduced by better knowledge of the defect relaxation.

  12. HelioVolt Corporation | Open Energy Information

    Open Energy Info (EERE)

    search Name: HelioVolt Corporation Place: Austin, Texas Zip: TX 78744 Product: Copper indium gallium selenide (CIGS) thin-film PV module manufacturer based in Austin,...

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

    DOE Patents [OSTI]

    Marks, Tobin J.; Chen, You-Xian

    2002-01-01

    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.

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

    DOE Patents [OSTI]

    Marks, Tobin J.; Chen, You-Xian

    2001-01-01

    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.

  15. Hydrogenation of palladium rich compounds of aluminium, gallium and indium

    SciTech Connect (OSTI)

    Kohlmann, H.

    2010-02-15

    Palladium rich intermetallic compounds of aluminium, gallium and indium have been studied before and after hydrogenation by powder X-ray diffraction and during hydrogenation by in situ thermal analysis (DSC) at hydrogen gas pressures up to 39 MPa and temperatures up to 700 K. Very weak DSC signals and small unit cell increases of below 1% for AlPd{sub 2}, AlPd{sub 3}, GaPd{sub 2}, Ga{sub 5}Pd{sub 13}, In{sub 3}Pd{sub 5}, and InPd{sub 2} suggest negligible hydrogen uptake. In contrast, for both tetragonal modifications of InPd{sub 3} (ZrAl{sub 3} and TiAl{sub 3} type), heating to 523 K at 2 MPa hydrogen pressure leads to a rearrangement of the intermetallic structure to a cubic AuCu{sub 3} type with an increase in unit cell volume per formula unit by 3.6-3.9%. Gravimetric analysis suggests a composition InPd{sub 3}H{sub a}pprox{sub 0.8} for the hydrogenation product. Very similar behaviour is found for the deuteration of InPd{sub 3}. - Graphical abstract: In situ differential scanning calorimetry of the hydrogenation of tetragonal InPd{sub 3} (ZrAl{sub 3} type) at 1.3 MPa hydrogen pressure.

  16. Spin-phonon coupling in scandium doped gallium ferrite

    SciTech Connect (OSTI)

    Chakraborty, Keka R. E-mail: smyusuf@barc.gov.in; Mukadam, M. D.; Basu, S.; Yusuf, S. M. E-mail: smyusuf@barc.gov.in; Paul, Barnita; Roy, Anushree; Grover, Vinita; Tyagi, A. K.

    2015-03-28

    We embarked on a study of Scandium (Sc) doped (onto Ga site) gallium ferrite (GaFeO{sub 3}) and found remarkable magnetic properties. In both doped as well as parent compounds, there were three types of Fe{sup 3+} ions (depending on the symmetry) with the structure conforming to space group Pna2{sub 1} (Sp. Grp. No. 33) below room temperature down to 5?K. We also found that all Fe{sup 3+} ions occupy octahedral sites, and carry high spin moment. For the higher Sc substituted sample (Ga{sub 1?x}Sc{sub x}FeO{sub 3}: x?=?0.3), a canted magnetic ordered state is found. Spin-phonon coupling below Nel temperature was observed in doped compounds. Our results indicated that Sc doping in octahedral site modifies spin-phonon interactions of the parent compound. The spin-phonon coupling strength was estimated for the first time in these Sc substituted compounds.

  17. Optical properties and plasmonic response of silver-gallium nanostructures

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

    Lereu, Aude; Lemarchand, F.; Zerrad, M.; Yazdanpanah, M.; Passian, Ali

    2015-02-12

    Silver and gallium form an alloy Ag2Ga via a room temperature spontaneous self-assembly that exhibits remarkable mechanical and electrical properties [1] suitable for nanoscale measurements [2]. However, whether photon excitation of plasmons in this emerging nanomaterial is retained or not has not been established. Here, we present a thin lm formation of Ag2Ga via a spreading- reactive process of liquid Ga on an Ag lm and a characterization of its dielectric function (E) = 1(E) - i 2(E) in the photon energy range 1.42 eV E <4.2 eV. It is observed that while the plasmon damping increases, near an energymore » of 3.4 eV, the real part of exhibits a crossing with respect to that of Ag. Furthermore, the impact of new plasmon supporting materials [3] is discussed and in order to enable further applications in plasmonics, the possibility of photon excitation of surface plasmons in Ag2Ga is studied.« less

  18. Ohmic contact formation process on low n-type gallium arsenide (GaAs) using indium gallium zinc oxide (IGZO)

    SciTech Connect (OSTI)

    Yang, Seong-Uk; Jung, Woo-Shik; Lee, In-Yeal; Jung, Hyun-Wook; Kim, Gil-Ho; Park, Jin-Hong

    2014-02-01

    Highlights: We propose a method to fabricate non-gold Ohmic contact on low n-type GaAs with IGZO. 0.15 A/cm{sup 2} on-current and 1.5 on/off-current ratio are achieved in the junction. InAs and InGaAs formed by this process decrease an electron barrier height. Traps generated by diffused O atoms also induce a trap-assisted tunneling phenomenon. - Abstract: Here, an excellent non-gold Ohmic contact on low n-type GaAs is demonstrated by using indium gallium zinc oxide and investigating through time of flight-secondary ion mass spectrometry, X-ray photoelectron spectroscopy, transmission electron microscopy, JV measurement, and H [enthalpy], S [entropy], Cp [heat capacity] chemistry simulation. In is diffused through GaAs during annealing and reacts with As, forming InAs and InGaAs phases with lower energy bandgap. As a result, it decreases the electron barrier height, eventually increasing the reverse current. In addition, traps generated by diffused O atoms induce a trap-assisted tunneling phenomenon, increasing generation current and subsequently the reverse current. Therefore, an excellent Ohmic contact with 0.15 A/cm{sup 2} on-current density and 1.5 on/off-current ratio is achieved on n-type GaAs.

  19. The comparison between gallium arsenide and indium gallium arsenide as materials for solar cell performance using Silvaco application

    SciTech Connect (OSTI)

    Zahari, Suhaila Mohd; Norizan, Mohd Natashah; Mohamad, Ili Salwani; Osman, Rozana Aina Maulat; Taking, Sanna

    2015-05-15

    The work presented in this paper is about the development of single and multilayer solar cells using GaAs and InGaAs in AM1.5 condition. The study includes the modeling structure and simulation of the device using Silvaco applications. The performance in term of efficiency of Indium Gallium Arsenide (InGaAs) and GaAs material was studied by modification of the doping concentration and thickness of material in solar cells. The efficiency of the GaAs solar cell was higher than InGaAs solar cell for single layer solar cell. Single layer GaAs achieved an efficiency about 25% compared to InGaAs which is only 2.65% of efficiency. For multilayer which includes both GaAs and InGaAs, the output power, P{sub max} was 8.91nW/cm² with the efficiency only 8.51%. GaAs is one of the best materials to be used in solar cell as a based compared to InGaAs.

  20. Deposition of metallic gallium on re-crystallized ceramic material during focused ion beam milling

    SciTech Connect (OSTI)

    Muoz-Tabares, J.A.; Reyes-Gasga, J.

    2013-12-15

    We report a new kind of artifact observed in the preparation of a TEM sample of zirconia by FIB, which consists in the deposition of metallic gallium nano-dots on the TEM sample surface. High resolution TEM images showed a microstructure of fine equiaxed grains of ? 5 nm, with some of them possessing two particular characteristics: high contrast and well-defined fast Fourier transform. These grains could not be identified as any phase of zirconia but it was possible to identify them as gallium crystals in the zone axis [110]. Based on HRTEM simulations, the possible orientations between zirconia substrate and deposited gallium are discussed in terms of lattice mismatch and oxygen affinity. - Highlights: We show a new type of artifact induced during preparation of TEM samples by FIB. Deposition of Ga occurs due to its high affinity for oxygen. Materials with small grain size (? 5 nm) could promote Ga deposition. Small grain size permits the elastic accommodation of deposited Ga.

  1. Study of the recombination process at crystallite boundaries in CuIn{sub 1-x}Ga{sub x}Se{sub 2} (CIGS) films by microwave photoconductivity

    SciTech Connect (OSTI)

    Bocharov, K. V.; Novikov, G. F.; Hsieh, T. Y.; Gapanovich, M. V.; Jeng, M. J.

    2013-03-15

    The loss kinetics of photogenerated charge carriers in thin polycrystalline chalcopyrite CuIn{sub 1-x}Ga{sub x}Se{sub 2} (CIGS) films has been studied by microwave photoconductivity (at 36 GHz). The films were synthesized using the ampoule method and three variants of physical vapor deposition with subsequent selenization: magnetron sputtering, thermal deposition, and modified thermal deposition with intermetallic precursors. The photoconductivity was excited by 8-ns nitrogen laser pulses with maximum intensity of 4 Multiplication-Sign 10{sup 14} photons/cm per pulse. Measurements were performed in the temperature range 148-293 K. The photoresponse amplitude is found to depend linearly on the sizes of coherent-scattering regions in the film grains, which were calculated from X-ray diffraction data. The photoresponse decay obeys hyperbolic law. The photoresponse half-decay time increases with a decrease in both temperature and light intensity. It is shown that the recombination of free holes with trapped electrons is very efficient near the crystallite boundaries.

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

    SciTech Connect (OSTI)

    Hofstetter, Markus; Howgate, John; Schmid, Martin; Schoell, Sebastian; Sachsenhauser, Matthias; Adiguezel, Denis; Stutzmann, Martin; Sharp, Ian D.; Thalhammer, Stefan

    2012-07-27

    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

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

    SciTech Connect (OSTI)

    Morris, R.N.

    1998-08-01

    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.

  4. Spontaneous and strong multi-layer graphene n-doping on soda-lime glass and its application in graphene-semiconductor junctions

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

    Dissanayake, D. M. N. M.; Ashraf, A.; Dwyer, D.; Kisslinger, K.; Zhang, L.; Pang, Y.; Efstathiadis, H.; Eisaman, M. D.

    2016-02-12

    Scalable and low-cost doping of graphene could improve technologies in a wide range of fields such as microelectronics, optoelectronics, and energy storage. While achieving strong p-doping is relatively straightforward, non-electrostatic approaches to n-dope graphene, such as chemical doping, have yielded electron densities of 9.5 × 1012 e/cm2 or below. Furthermore, chemical doping is susceptible to degradation and can adversely affect intrinsic graphene’s properties. Here we demonstrate strong (1.33 × 1013 e/cm2), robust, and spontaneous graphene n-doping on a soda-lime-glass substrate via surface-transfer doping from Na without any external chemical, high-temperature, or vacuum processes. Remarkably, the n-doping reaches 2.11 × 1013more » e/cm2 when graphene is transferred onto a p-type copper indium gallium diselenide (CIGS) semiconductor that itself has been deposited onto soda-lime-glass, via surface-transfer doping from Na atoms that diffuse to the CIGS surface. Using this effect, we demonstrate an n-graphene/p-semiconductor Schottky junction with ideality factor of 1.21 and strong photo-response. As a result, the ability to achieve strong and persistent graphene n-doping on low-cost, industry-standard materials paves the way toward an entirely new class of graphene-based devices such as photodetectors, photovoltaics, sensors, batteries, and supercapacitors.« less

  5. Flexible Ultra Moisture Barrier Film for Thin-Film Photovoltaic Applications

    SciTech Connect (OSTI)

    David M. Dean

    2012-10-30

    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.

  6. Sandia Demonstrated First-Time, Single-Mode Lasing in Gallium-Nitride

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

    Nanowire Lasers Demonstrated First-Time, Single-Mode Lasing in Gallium-Nitride Nanowire Lasers - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization

  7. Gallium hole traps in irradiated KTiOPO{sub 4}:Ga crystals

    SciTech Connect (OSTI)

    Grachev, V.; Meyer, M.; Malovichko, G.; Hunt, A. W.

    2014-12-07

    Nominally pure and gallium doped single crystals of potassium titanyl phosphate (KTiOPO{sub 4}) have been studied by Electron Paramagnetic Resonance at low temperatures before and after irradiation. Irradiation with 20?MeV electrons performed at room temperature and liquid nitrogen temperature caused an appearance of electrons and holes. Gallium impurities act as hole traps in KTiOPO{sub 4} creating Ga{sup 4+} centers. Two different Ga{sup 4+} centers were observed, Ga1 and Ga2. The Ga1 centers are dominant in Ga-doped samples. For the Ga1 center, a superhyperfine structure with one nucleus with nuclear spin was registered and attributed to the interaction of gallium electrons with a phosphorus nucleus or proton in its surrounding. In both Ga1 and Ga2 centers, Ga{sup 4+} ions substitute for Ti{sup 4+} ions, but with a preference to one of two electrically distinct crystallographic positions (site selective substitution). The Ga doping eliminates one of the shortcomings of KTP crystalsionic conductivity of bulk crystals. However, this does not improve significantly the resistance of the crystals to electron and ?-radiation.

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

    DOE Patents [OSTI]

    Marks, Tobin J.; Chen, You-Xian

    2001-01-01

    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.

  9. Controlled VLS Growth of Indium, Gallium and Tin Oxide Nanowiresvia Chemical Vapor Transport

    SciTech Connect (OSTI)

    Johnson, M.C.; Aloni, S.; McCready, D.E.; Bourret-Courchesne, E.D.

    2006-03-13

    We utilized a vapor-liquid-solid growth technique to synthesize indium oxide, gallium oxide, and tin oxide nanowires using chemical vapor transport with gold nanoparticles as the catalyst. Using identical growth parameters we were able to synthesize single crystal nanowires typically 40-100 nm diameter and more than 10-100 microns long. The products were characterized by means of XRD, SEM and HRTEM. All the wires were grown under the same growth conditions with growth rates inversely proportional to the source metal vapor pressure. Initial experiments show that different transparent oxide nanowires can be grown simultaneously on a single substrate with potential application for multi-component gas sensors.

  10. Modification of the crystal structure of gadolinium gallium garnet by helium ion irradiation

    SciTech Connect (OSTI)

    Ostafiychuk, B. K.; Yaremiy, I. P. Yaremiy, S. I.; Fedoriv, V. D.; Tomyn, U. O.; Umantsiv, M. M.; Fodchuk, I. M.; Kladko, V. P.

    2013-12-15

    The structure of gadolinium gallium garnet (GGG) single crystals before and after implantation by He{sup +} ions has been investigated using high-resolution X-ray diffraction methods and the generalized dynamic theory of X-ray scattering. The main types of growth defects in GGG single crystals and radiation-induced defects in the ion-implanted layer have been determined. It is established that the concentration of dislocation loops in the GGG surface layer modified by ion implantation increases and their radius decreases with an increase in the implantation dose.

  11. 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)

    2008-04-15

    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.

  12. Short-range order and dynamics of atoms in liquid gallium

    SciTech Connect (OSTI)

    Mokshin, A. V. Khusnutdinoff, R. M.; Novikov, A. G.; Blagoveshchenskii, N. M.; Puchkov, A. V.

    2015-11-15

    The features of the microscopic structure, as well as one-particle and collective dynamics of liquid gallium in the temperature range from T = 313 to 1273 K, are studied on the p = 1.0 atm isobar. Detailed analysis of the data on diffraction of neutrons and X-rays, as well as the results of atomic dynamics simulation, lead to some conclusions about the structure. In particular, for preset conditions, gallium is in the equilibrium liquid phase showing no features of any stable local crystalline clusters. The pronounced asymmetry of the principle peak of the static structure factor and the characteristic “shoulder” in its right-hand part appearing at temperatures close to the melting point, which are clearly observed in the diffraction data, are due to the fact that the arrangement of the nearest neighbors of an arbitrary atom in the system is estimated statistically from the range of correlation length values and not by a single value as in the case of simple liquids. Compactly located dimers with a very short bond make a significant contribution to the statistics of nearest neighbors. The temperature dependence of the self-diffusion coefficient calculated from atomic dynamics simulation agrees well with the results obtained from experimental spectra of the incoherent scattering function. Interpolation of the temperature dependence of the self-diffusion coefficient on a logarithmic scale reveals two linear regions with a transition temperature of about 600 K. The spectra of the dynamic structure factor and spectral densities of the local current calculated by simulating the atomic dynamics indicate the existence of acoustic vibrations with longitudinal and transverse polarizations in liquid gallium, which is confirmed by experimental data on inelastic scattering of neutrons and X-rays. It is found that the vibrational density of states is completely reproduced by the generalized Debye model, which makes it possible to decompose the total vibrational motion into

  13. Resonant second harmonic generation in a gallium nitride two-dimensional photonic crystal on silicon

    SciTech Connect (OSTI)

    Zeng, Y.; Roland, I.; Checoury, X.; Han, Z.; El Kurdi, M.; Sauvage, S.; Boucaud, P.; Gayral, B.; Brimont, C.; Guillet, T.; Mexis, M.; Semond, F.

    2015-02-23

    We demonstrate second harmonic generation in a gallium nitride photonic crystal cavity embedded in a two-dimensional free-standing photonic crystal platform on silicon. The photonic crystal nanocavity is optically pumped with a continuous-wave laser at telecom wavelengths in the transparency window of the nitride material. The harmonic generation is evidenced by the spectral range of the emitted signal, the quadratic power dependence vs. input power, and the spectral dependence of second harmonic signal. The harmonic emission pattern is correlated to the harmonic polarization generated by the second-order nonlinear susceptibilities χ{sub zxx}{sup (2)}, χ{sub zyy}{sup (2)} and the electric fields of the fundamental cavity mode.

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

    SciTech Connect (OSTI)

    Sallis, S.; Williams, D. S.; Butler, K. T.; Walsh, A.; Quackenbush, N. F.; Junda, M.; Podraza, N. J.; Fischer, D. A.; Woicik, J. C.; White, B. E.; Piper, L. F. J.

    2014-06-09

    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.

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

    SciTech Connect (OSTI)

    Muhammad, R.; Ahamad, R.; Ibrahim, Z.; Othaman, Z.

    2014-03-05

    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.

  16. 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.

    1998-01-01

    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.

  17. 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.

    2013-06-01

    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.

  18. Imaging the p-n junction in a gallium nitride nanowire with a scanning microwave microscope

    SciTech Connect (OSTI)

    Imtiaz, Atif; Wallis, Thomas M.; Brubaker, Matt D.; Blanchard, Paul T.; Bertness, Kris A.; Sanford, Norman A.; Kabos, Pavel; Weber, Joel C.; Coakley, Kevin J.

    2014-06-30

    We used a broadband, atomic-force-microscope-based, scanning microwave microscope (SMM) to probe the axial dependence of the charge depletion in a p-n junction within a gallium nitride nanowire (NW). SMM enables the visualization of the p-n junction location without the need to make patterned electrical contacts to the NW. Spatially resolved measurements of S{sub 11}{sup ?}, which is the derivative of the RF reflection coefficient S{sub 11} with respect to voltage, varied strongly when probing axially along the NW and across the p-n junction. The axial variation in S{sub 11}{sup ?}? effectively mapped the asymmetric depletion arising from the doping concentrations on either side of the junction. Furthermore, variation of the probe tip voltage altered the apparent extent of features associated with the p-n junction in S{sub 11}{sup ?} images.

  19. 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.

    2006-10-03

    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.

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

    SciTech Connect (OSTI)

    Not Available

    2012-09-01

    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.'

  1. Thin-Film Photovoltaics on Solar House

    Broader source: Energy.gov [DOE]

    In this photograph, people are reflected on Team Germany's window louvers with integrated thin-film copper indium gallium selenide (CIGS) cells during the U.S. Department of Energy Solar Decathlon...

  2. PROJECT PROFILE: University of Illinois-Urbana Champaign (PREDICTS...

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

    how to reduce the instability of materials used for copper indium gallium selenide solar (CIGS) cells or thin film photovoltaics (PV) when they are exposed to water and light. ...

  3. Transport-reaction model for defect and carrier behavior within displacement cascades in gallium arsenide

    SciTech Connect (OSTI)

    Wampler, William R.; Myers, Samuel M.

    2014-02-01

    A model is presented for recombination of charge carriers at displacement damage in gallium arsenide, which includes clustering of the defects in atomic displacement cascades produced by neutron or ion irradiation. The carrier recombination model is based on an atomistic description of capture and emission of carriers by the defects with time evolution resulting from the migration and reaction of the defects. The physics and equations on which the model is based are presented, along with details of the numerical methods used for their solution. The model uses a continuum description of diffusion, field-drift and reaction of carriers and defects within a representative spherically symmetric cluster. The initial radial defect profiles within the cluster were chosen through pair-correlation-function analysis of the spatial distribution of defects obtained from the binary-collision code MARLOWE, using recoil energies for fission neutrons. Charging of the defects can produce high electric fields within the cluster which may influence transport and reaction of carriers and defects, and which may enhance carrier recombination through band-to-trap tunneling. Properties of the defects are discussed and values for their parameters are given, many of which were obtained from density functional theory. The model provides a basis for predicting the transient response of III-V heterojunction bipolar transistors to pulsed neutron irradiation.

  4. Revealing the preferred interlayer orientations and stackings of two-dimensional bilayer gallium selenide crystals

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

    Li, Xufan; Basile Carrasco, Leonardo A.; Yoon, Mina; Ma, Cheng; Puretzky, Alexander A.; Lee, Jaekwang; Idrobo Tapia, Juan Carlos; Chi, Miaofang; Rouleau, Christopher M.; Geohegan, David B.; et al

    2015-01-21

    Characterizing and controlling the interlayer orientations and stacking order of bilayer two-dimensional (2D) crystals and van der Waals (vdW) heterostructure is crucial to optimize their electrical and optoelectronic properties. The four polymorphs of layered gallium selenide (GaSe) that result from different layer stacking provide an ideal platform to study the stacking configurations in bilayer 2D crystals. Here, through a controllable vapor-phase deposition method we selectively grow bilayer GaSe crystals and investigate their two preferred 0° or 60° interlayer rotations. The commensurate stacking configurations (AA' and AB-stacking) in as-grown 2D bilayer GaSe crystals are clearly observed at the atomic scale andmore » the Ga-terminated edge structure are identified for the first time by using atomic-resolution scanning transmission electron microscopy (STEM). Theoretical analysis of the interlayer coupling energetics vs. interlayer rotation angle reveals that the experimentally-observed orientations are energetically preferred among the bilayer GaSe crystal polytypes. Here, the combined experimental and theoretical characterization of the GaSe bilayers afforded by these growth studies provide a pathway to reveal the atomistic relationships in interlayer orientations responsible for the electronic and optical properties of bilayer 2D crystals and vdW heterostructures.« less

  5. Revealing the preferred interlayer orientations and stackings of two-dimensional bilayer gallium selenide crystals

    SciTech Connect (OSTI)

    Li, Xufan; Basile Carrasco, Leonardo A.; Yoon, Mina; Ma, Cheng; Puretzky, Alexander A.; Lee, Jaekwang; Idrobo Tapia, Juan Carlos; Chi, Miaofang; Rouleau, Christopher M.; Geohegan, David B.; Xiao, Kai

    2015-01-21

    Characterizing and controlling the interlayer orientations and stacking order of bilayer two-dimensional (2D) crystals and van der Waals (vdW) heterostructure is crucial to optimize their electrical and optoelectronic properties. The four polymorphs of layered gallium selenide (GaSe) that result from different layer stacking provide an ideal platform to study the stacking configurations in bilayer 2D crystals. Here, through a controllable vapor-phase deposition method we selectively grow bilayer GaSe crystals and investigate their two preferred 0° or 60° interlayer rotations. The commensurate stacking configurations (AA' and AB-stacking) in as-grown 2D bilayer GaSe crystals are clearly observed at the atomic scale and the Ga-terminated edge structure are identified for the first time by using atomic-resolution scanning transmission electron microscopy (STEM). Theoretical analysis of the interlayer coupling energetics vs. interlayer rotation angle reveals that the experimentally-observed orientations are energetically preferred among the bilayer GaSe crystal polytypes. Here, the combined experimental and theoretical characterization of the GaSe bilayers afforded by these growth studies provide a pathway to reveal the atomistic relationships in interlayer orientations responsible for the electronic and optical properties of bilayer 2D crystals and vdW heterostructures.

  6. Revealing the Preferred Interlayer Orientations and Stackings of Two-Dimensional Bilayer Gallium Selenide Crystals

    SciTech Connect (OSTI)

    Li, Xufan; Basile Carrasco, Leonardo A; Yoon, Mina; Ma, Cheng; Puretzky, Alexander A; Lee, Jaekwang; Idrobo Tapia, Juan Carlos; Chi, Miaofang; Rouleau, Christopher M; Geohegan, David B; Xiao, Kai

    2015-01-01

    Characterizing and controlling the interlayer orientations and stacking order of bilayer two-dimensional (2D) crystals and van der Waals (vdW) heterostructure is crucial to optimize their electrical and optoelectronic properties. The four polymorphs of layered gallium selenide (GaSe) that result from different layer stacking provide an ideal platform to study the stacking configurations in bilayer 2D crystals. Here, through a controllable vapor-phase deposition method we selectively grow bilayer GaSe crystals and investigate their two preferred 0 or 60 interlayer rotations. The commensurate stacking configurations (AA and AB-stacking) in as-grown 2D bilayer GaSe crystals are clearly observed at the atomic scale and the Ga-terminated edge structure are identified for the first time by using atomic-resolution scanning transmission electron microscopy (STEM). Theoretical analysis of the interlayer coupling energetics vs. interlayer rotation angle reveals that the experimentally-observed orientations are energetically preferred among the bilayer GaSe crystal polytypes. The combined experimental and theoretical characterization of the GaSe bilayers afforded by these growth studies provide a pathway to reveal the atomistic relationships in interlayer orientations responsible for the electronic and optical properties of bilayer 2D crystals and vdW heterostructures.

  7. Steady State Sputtering Yields and Surface Compositions of Depleted Uranium and Uranium Carbide bombarded by 30 keV Gallium or 16 keV Cesium Ions.

    SciTech Connect (OSTI)

    Siekhaus, W. J.; Teslich, N. E.; Weber, P. K.

    2014-10-23

    Depleted uranium that included carbide inclusions was sputtered with 30-keV gallium ions or 16-kev cesium ions to depths much greater than the ions’ range, i.e. using steady-state sputtering. The recession of both the uranium’s and uranium carbide’s surfaces and the ion corresponding fluences were used to determine the steady-state target sputtering yields of both uranium and uranium carbide, i.e. 6.3 atoms of uranium and 2.4 units of uranium carbide eroded per gallium ion, and 9.9 uranium atoms and 3.65 units of uranium carbide eroded by cesium ions. The steady state surface composition resulting from the simultaneous gallium or cesium implantation and sputter-erosion of uranium and uranium carbide were calculated to be U₈₆Ga₁₄, (UC)₇₀Ga₃₀ and U₈₁Cs₉, (UC)₇₉Cs₂₁, respectively.

  8. 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.; Qu, P.; Qu, Hongwei; Petrov, V. M.; Fetisov, Y. K.; Nosov, A. P.

    2014-07-21

    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.

  9. Gallium and indium imaging agents. 2. Complexes of sulfonated catecholyamide sequestering agents

    SciTech Connect (OSTI)

    Pecoraro, V.L.; Wong, G.B.; Raymond, K.N.

    1982-06-01

    The solution equilibria for the reaction of Ga(III) and In(III) with the hexadentate ligands N, N', N''-tris(2,3-dihydroxy-5-sulfonatobenzoyl)-1,3,5-tris(aminomethyl)benzene (MECAMS) and N, N', N''-tris(2,3-dihydroxy-5-sulfonatobenzoyl)-1,5,10-triazadecane (3,4-LICAMS) and the bidentate catechol N,N-dimethyl-2,3-dihydroxy-5-sulfonatobenzamide (DMBS) have been determined on 0.1 M KNO/sub 3/ at 25/sup 0/C. Both Ga(III) and In(III) are coordinated by three catecholate groups at high pH and have formation constants of the order ..beta../sub 110/ = 10/sup 38/ M/sup -1/. As the acidity of the medium is increased, the metal complexes of the hexadentate sequestering agents undergo protonation reactions. For the determination of the nature of the protonated metal chelates, the stretching frequency of the amide carbonyl has been monitored in D/sub 2/O by Fourier transform infrared spectroscopy (FT IR). These data support a series of two one-proton steps to form a mixed salicylate-catecholate coordination about the metal ion. In the salicylate bonding mode the metal is bound through the ortho phenolic oxygen and the amide cabonyl whereas catecholate coordination is via the adjacent phenols. In contrast, protonation of the M/sup III/(DMBS)/sub 3/ complexes results in dissociation of a catechol moiety to form M/sup III/(DMBS)/sub 2/. The potential use of these compounds as tumor-imaging agents in cancer diagnosis is discussed, with specific attention to the role of the gallium transferrin complex.

  10. 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.; Miedaner, Alexander; Van Hest, Maikel; Ginley, David S.; Nekuda, Jennifer A.

    2011-11-15

    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).

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

    SciTech Connect (OSTI)

    2010-10-01

    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.

  12. Recovery from ultraviolet-induced threshold voltage shift in indium gallium zinc oxide thin film transistors by positive gate bias

    SciTech Connect (OSTI)

    Liu, P.; Chen, T. P.; Li, X. D.; Wong, J. I.; Liu, Z.; Liu, Y.; Leong, K. C.

    2013-11-11

    The effect of short-duration ultraviolet (UV) exposure on the threshold voltage (V{sub th}) of amorphous indium gallium zinc oxide thin film transistors (TFTs) and its recovery characteristics were investigated. The V{sub th} exhibited a significant negative shift after UV exposure. The V{sub th} instability caused by UV illumination is attributed to the positive charge trapping in the dielectric layer and/or at the channel/dielectric interface. The illuminated devices showed a slow recovery in threshold voltage without external bias. However, an instant recovery can be achieved by the application of positive gate pulses, which is due to the elimination of the positive trapped charges as a result of the presence of a large amount of field-induced electrons in the interface region.

  13. 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.

    2009-05-04

    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.

  14. Plasmon resonance and perfect light absorption in subwavelength trench arrays etched in gallium-doped zinc oxide film

    SciTech Connect (OSTI)

    Hendrickson, Joshua R. Leedy, Kevin; Cleary, Justin W.; Vangala, Shivashankar; Nader, Nima; Guo, Junpeng

    2015-11-09

    Near-perfect light absorption in subwavelength trench arrays etched in highly conductive gallium-doped zinc oxide films was experimentally observed in the mid infrared regime. At wavelengths corresponding to the resonant excitation of surface plasmons, up to 99% of impinging light is efficiently trapped and absorbed in the periodic trenches. Scattering cross sectional calculations reveal that each individual trench acts like a vertical split ring resonator with a broad plasmon resonance spectrum. The coupling of these individual plasmon resonators in the grating structure leads to enhanced photon absorption and significant resonant spectral linewidth narrowing. Ellipsometry measurements taken before and after device fabrication result in different permittivity values for the doped zinc oxide material, indicating that localized annealing occurred during the plasma etching process due to surface heating. Simulations, which incorporate a 50 nm annealed region at the zinc oxide surface, are in a good agreement with the experimental results.

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

    SciTech Connect (OSTI)

    Wissman, J.; Finkenauer, L.; Deseri, L.; Majidi, C.

    2014-10-14

    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 Φ 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 ϑ. 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 Φ. Based on this theory, we predict a dependency of ϑ on Φ 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.

  16. Light-trapping and recycling for extraordinary power conversion in ultra-thin gallium-arsenide solar cells

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

    Eyderman, Sergey; John, Sajeev

    2016-06-23

    Here, we demonstrate nearly 30% power conversion efficiency in ultra-thin (~200 nm) gallium arsenide photonic crystal solar cells by numerical solution of the coupled electromagnetic Maxwell and semiconductor drift-diffusion equations. Our architecture enables wave-interference-induced solar light trapping in the wavelength range from 300-865 nm, leading to absorption of almost 90% of incoming sunlight. Our optimized design for 200 nm equivalent bulk thickness of GaAs, is a square-lattice, slanted conical-pore photonic crystal (lattice constant 550 nm, pore diameter 600 nm, and pore depth 290 nm), passivated with AlGaAs, deposited on a silver back-reflector, with ITO upper contact and encapsulated with SiO2.more » Our model includes both radiative and non-radiative recombination of photo-generated charge carriers. When all light from radiative recombination is assumed to escape the structure, a maximum achievable photocurrent density (MAPD) of 27.6 mA/cm2 is obtained from normally incident AM 1.5 sunlight. For a surface non-radiative recombination velocity of 103 cm/s, this corresponds to a solar power conversion efficiency of 28.3%. When all light from radiative recombination is trapped and reabsorbed (complete photon recycling) the power conversion efficiency increases to 29%. If the surface recombination velocity is reduced to 10 cm/sec, photon recycling is much more effective and the power conversion efficiency reaches 30.6%.« less

  17. (Ion beam deposition of epitaxial germanium and gallium arsenide layers): Foreign trip report, June 2, 1989--June 18, 1989

    SciTech Connect (OSTI)

    Haynes, T.E.

    1989-07-05

    The traveler presented an invited paper entitled ''Ion Beam Deposition of Epitaxial Germanium and Gallium Arsenide Layers'' at the Twelfth Symposium on Ion Sources and Ion-Assisted Technology (ISIAT '89) in Tokyo. During informal conversations at this meeting, the traveler was informed about a new Japanese initiative, sponsored by the Ministry of International Trade and Industry and an industrial consortium, to establish an Ion Engineering Research Center, whose purpose will be to provide sophisticated equipment and technology base for exploring and developing new applications of ion beam processing. The traveler also visited five Japanese laboratories involved in research on ion-solid interactions. Developments in ionized cluster beam (ICB) deposition were emphasized at ISIAT '89 and during visits to Kyoto University, where the ICB technique was pioneered, and to Mitsubishi Electric's Itami Works, where commercial ICB systems are now being produced. Discussions at Osaka University concentrated on the application of focused ion beams for maskless patterning of submicron devices and on recent studies of one- dimensional quantum effects in semiconductor wires. At Hitachi Research Laboratory, basic research on thin-film growth was described, as well as progress toward the development of a variable frequency RF quadrupole accelerator for ion implantation. Researchers at JAERI outlined programs in characterization and thin-film deposition of superconductors and in materials science studies using high-energy ion beams.

  18. Effects of low-temperature (120 °C) annealing on the carrier concentration and trap density in amorphous indium gallium zinc oxide thin film transistors

    SciTech Connect (OSTI)

    Kim, Jae-sung; Piao, Mingxing; Jang, Ho-Kyun; Kim, Gyu-Tae; Oh, Byung Su; Joo, Min-Kyu; Ahn, Seung-Eon

    2014-12-28

    We report an investigation of the effects of low-temperature annealing on the electrical properties of amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs). X-ray photoelectron spectroscopy was used to characterize the charge carrier concentration, which is related to the density of oxygen vacancies. The field-effect mobility was found to decrease as a function of the charge carrier concentration, owing to the presence of band-tail states. By employing the transmission line method, we show that the contact resistance did not significantly contribute to the changes in device performance after annealing. In addition, using low-frequency noise analyses, we found that the trap density decreased by a factor of 10 following annealing at 120 °C. The switching operation and on/off ratio of the a-IGZO TFTs improved considerably after low-temperature annealing.

  19. Growth of gallium nitride films via the innovative technique of atomic-layer epitaxy. Annual progress report, 1 June 1987-31 May 1988

    SciTech Connect (OSTI)

    Davis, R.F.; Paisley, M.J.; Sitar, Z.

    1988-06-01

    Gallium nitride (GaN) is a wide-bandgap (3.45 eV at 300K) III-V compound semiconductor. The large direct bandgap and high electron-drift velocity of GaN are important properties in the performance of short-wavelength optical devices and high-power microwave devices. Immediate applications that would be greatly enhanced by the availability of GaN and/or Al/sub x/Ga/sub 1-x/N devices include threat warning systems (based on the ultraviolet (UV) emission from the exhaust plumes of missiles) and radar systems (which require high-power microwave generation). Important future applications for devices produced from these materials include blue and ultraviolet semiconductor lasers, blue-light-emitting diodes (LEDs) and high temperature electronic devices. This report discusses this material.

  20. Results from Coupled Optical and Electrical Sentaurus TCAD Models of a Gallium Phosphide on Silicon Electron Carrier Selective Contact Solar Cell

    SciTech Connect (OSTI)

    Limpert, Steven; Ghosh, Kunal; Wagner, Hannes; Bowden, Stuart; Honsberg, Christiana; Goodnick, Stephen; Bremner, Stephen; Green, Martin

    2014-06-09

    We report results from coupled optical and electrical Sentaurus TCAD models of a gallium phosphide (GaP) on silicon electron carrier selective contact (CSC) solar cell. Detailed analyses of current and voltage performance are presented for devices having substrate thicknesses of 10 μm, 50 μm, 100 μm and 150 μm, and with GaP/Si interfacial quality ranging from very poor to excellent. Ultimate potential performance was investigated using optical absorption profiles consistent with light trapping schemes of random pyramids with attached and detached rear reflector, and planar with an attached rear reflector. Results indicate Auger-limited open-circuit voltages up to 787 mV and efficiencies up to 26.7% may be possible for front-contacted devices.

  1. Realization of write-once-read-many-times memory device with O{sub 2} plasma-treated indium gallium zinc oxide thin film

    SciTech Connect (OSTI)

    Liu, P. Chen, T. P. Li, X. D.; Wong, J. I.; Liu, Z.; Liu, Y.; Leong, K. C.

    2014-01-20

    A write-once-read-many-times (WORM) memory devices based on O{sub 2} plasma-treated indium gallium zinc oxide (IGZO) thin films has been demonstrated. The device has a simple Al/IGZO/Al structure. The device has a normally OFF state with a very high resistance (e.g., the resistance at 2?V is ?10{sup 9} ? for a device with the radius of 50??m) as a result of the O{sub 2} plasma treatment on the IGZO thin films. The device could be switched to an ON state with a low resistance (e.g., the resistance at 2?V is ?10{sup 3} ? for the radius of 50??m) by applying a voltage pulse (e.g., 10?V/1??s). The WORM device has good data-retention and reading-endurance capabilities.

  2. 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

  3. Post-Deposition Treatment Boosts CIGS Solar Cell Performance...

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

    These experiments led to a 16.2%-efficient solar cell fabricated from the CuGa In stacked metal precursor. But the goal was to increase the efficiency and decrease the time ...

  4. A Mechanistic Study of CO2 Reduction at the Interface of a Gallium Phosphide (GaP) Surface using Core-level Spectroscopy - Oral Presentation

    SciTech Connect (OSTI)

    Flynn, Kristen

    2015-08-19

    Carbon dioxide (CO2) emission into the atmosphere has increased tremendously through burning of fossil fuels, forestry, etc.. The increased concentration has made CO2 reductions very attractive though the reaction is considered uphill. Utilizing the sun as a potential energy source, CO2 has the possibility to undergo six electron and four proton transfers to produce methanol, a useable resource. This reaction has been shown to occur selectively in an aqueous pyridinium solution with a gallium phosphide (GaP) electrode. Though this reaction has a high faradaic efficiency, it was unclear as to what role the GaP surface played during the reaction. In this work, we aim to address the fundamental role of GaP during the catalytic conversion, by investigating the interaction between a clean GaP surface with the reactants, products, and intermediates of this reaction using X-ray photoelectron spectroscopy. We have determined a procedure to prepare atomically clean GaP and our initial CO2 adsorption studies have shown that there is evidence of chemisorption and reaction to form carbonate on the clean surface at LN2 temperatures (80K), in contrast to previous theoretical calculations. These findings will enable future studies on CO2 catalysis.

  5. A Mechanistic Study of CO2 Reduction at the Interface of a Gallium Phosphide (GaP) Surface using Core-level Spectroscopy

    SciTech Connect (OSTI)

    Flynn, Kristen

    2015-08-18

    Carbon dioxide (CO2) emission into the atmosphere has increased tremendously through burning of fossil fuels, forestry, etc.. The increased concentration has made CO2 reductions very attractive though the reaction is considered uphill. Utilizing the sun as a potential energy source, CO2 has the possibility to undergo six electron and four proton transfers to produce methanol, a useable resource. This reaction has been shown to occur selectively in an aqueous pyridinium solution with a gallium phosphide (GaP) electrode. Though this reaction has a high faradaic efficiency, it was unclear as to what role the GaP surface played during the reaction. In this work, we aim to address the fundamental role of GaP during the catalytic conversion, by investigating the interaction between a clean GaP surface with the reactants, products, and intermediates of this reaction using X-ray photoelectron spectroscopy. We have determined a procedure to prepare atomically clean GaP and our initial CO2 adsorption studies have shown that there is evidence of chemisorption and reaction to form carbonate on the clean surface at LN2 temperatures (80K), in contrast to previous theoretical calculations. These findings will enable future studies on CO2 catalysis.

  6. NREL: Photovoltaics Research - Testing and Analysis to Advance R&D

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

    Testing and Analysis to Advance R&D Get the Adobe Flash Player to see this video. Text Alternative NREL has capabilities and experts in measurements, characterization, reliability, engineering, scientific computing, and theory to support photovoltaic (PV) research and development (R&D) across a range of conversion technologies and scales. Conversion technologies include the primary areas of silicon, polycrystalline thin films (cadmium telluride [CdTe], copper indium gallium diselenide

  7. Effect of top gate bias on photocurrent and negative bias illumination stress instability in dual gate amorphous indium-gallium-zinc oxide thin-film transistor

    SciTech Connect (OSTI)

    Lee, Eunji; Chowdhury, Md Delwar Hossain; Park, Min Sang; Jang, Jin

    2015-12-07

    We have studied the effect of top gate bias (V{sub TG}) on the generation of photocurrent and the decay of photocurrent for back channel etched inverted staggered dual gate structure amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film-transistors. Upon 5 min of exposure of 365 nm wavelength and 0.7 mW/cm{sup 2} intensity light with negative bottom gate bias, the maximum photocurrent increases from 3.29 to 322 pA with increasing the V{sub TG} from −15 to +15 V. By changing V{sub TG} from negative to positive, the Fermi level (E{sub F}) shifts toward conduction band edge (E{sub C}), which substantially controls the conversion of neutral vacancy to charged one (V{sub O} → V{sub O}{sup +}/V{sub O}{sup 2+} + e{sup −}/2e{sup −}), peroxide (O{sub 2}{sup 2−}) formation or conversion of ionized interstitial (O{sub i}{sup 2−}) to neutral interstitial (O{sub i}), thus electron concentration at conduction band. With increasing the exposure time, more carriers are generated, and thus, maximum photocurrent increases until being saturated. After negative bias illumination stress, the transfer curve shows −2.7 V shift at V{sub TG} = −15 V, which gradually decreases to −0.42 V shift at V{sub TG} = +15 V. It clearly reveals that the position of electron quasi-Fermi level controls the formation of donor defects (V{sub O}{sup +}/V{sub O}{sup 2+}/O{sub 2}{sup 2−}/O{sub i}) and/or hole trapping in the a-IGZO /interfaces.

  8. PROJECT PROFILE: Case Western Reserve University (PVRD-SIPS)

    Broader source: Energy.gov [DOE]

    This project investigates the impact of surface modification of the transparent electrode in thin film copper indium gallium selenide (CIGS) solar cells on improving the reliability. The modification with a molecular surface modifier will limit chemical exposure of the cell to water and acetic acid from the breakdown of ethylene-vinyl-acetate (EVA) encapsulants. The modification is expected to double the lifetime of the cell.

  9. Fundamental Materials Research and Advanced Process Development for Thin-Film CIS-Based Photovoltaics: Final Technical Report, 2 October 2001 - 30 September 2005

    SciTech Connect (OSTI)

    Anderson, T. J.; Li, S. S.; Crisalle, O. D.; Craciun, V.

    2006-09-01

    The objectives for this thin-film copper-indium-diselenide (CIS) solar cell project cover the following areas: Develop and characterize buffer layers for CIS-based solar cell; grow and characterize chemical-bath deposition of Znx Cd1-xS buffer layers grown on CIGS absorbers; study effects of buffer-layer processing on CIGS thin films characterized by the dual-beam optical modulation technique; grow epitaxial CuInSe2 at high temperature; study the defect structure of CGS by photoluminescence spectroscopy; investigate deep-level defects in Cu(In,Ga)Se2 solar cells by deep-level transient spectroscopy; conduct thermodynamic modeling of the isothermal 500 C section of the Cu-In-Se system using a defect model; form alpha-CuInSe2 by rapid thermal processing of a stacked binary compound bilayer; investigate pulsed non-melt laser annealing on the film properties and performance of Cu(In,Ga)Se2 solar cells; and conduct device modeling and simulation of CIGS solar cells.

  10. Longitudinal spin Seebeck effect in Nd{sub 2}BiFe{sub 5−x}Ga{sub x}O{sub 12} prepared on gadolinium gallium garnet (001) by metal organic decomposition method

    SciTech Connect (OSTI)

    Asada, H. Kuwahara, A.; Sakata, N.; Ono, T.; Kishimoto, K.; Koyanagi, T.; Ishibashi, T.; Meguro, A.; Hashinaka, T.

    2015-05-07

    Nd{sub 2}BiFe{sub 5−x}Ga{sub x}O{sub 12} thin films with the Ga composition x = 0, 0.5, and 1.0 are prepared on (001) oriented gadolinium gallium garnet substrates by a metal organic decomposition method. Only (001) peaks are observed in x-ray diffraction patterns for all the films, suggesting that the highly oriented Nd{sub 2}BiFe{sub 5−x}Ga{sub x}O{sub 12} thin films were formed. Increasing Ga composition, the saturation magnetization decreases, and the perpendicular easy axis is enhanced due to the decrease of the shape anisotropy. Longitudinal spin Seebeck effects (LSSEs) in Nd{sub 2}BiFe{sub 5−x}Ga{sub x}O{sub 12} thin films with a Pt layer of 10 nm in thickness were investigated. Magnetic field dependence of the thermoelectric voltage caused by the LSSE in Nd{sub 2}BiFe{sub 5−x}Ga{sub x}O{sub 12} films indicates the hysteresis loop with the small coercivity reflecting the magnetization curve. The decrease of LSSE voltage in Nd{sub 2}BiFe{sub 5−x}Ga{sub x}O{sub 12} is clearly observed with the decrease of Fe composition.

  11. The state of the art of thin-film photovoltaics

    SciTech Connect (OSTI)

    Surek, T.

    1993-10-01

    Thin-film photovoltaic technologies, based on materials such as amorphous or polycrystalline silicon, copper indium diselenide, cadmium telluride, and gallium arsenide, offer the potential for significantly reducing the cost of electricity generated by photovoltaics. The significant progress in the technologies, from the laboratory to the marketplace, is reviewed. The common concerns and questions raised about thin films are addressed. Based on the progress to date and the potential of these technologies, along with continuing investments by the private sector to commercialize the technologies, one can conclude that thin-film PV will provide a competitive alternative for large-scale power generation in the future.

  12. Method of synthesizing and growing copper-indium-diselenide (CuInSe.sub.2) crystals

    DOE Patents [OSTI]

    Ciszek, Theodore F.

    1987-01-01

    A process for preparing CuInSe.sub.2 crystals includes melting a sufficient quantity of B.sub.2 O.sub.3 along with stoichiometric quantities of Cu, In, and Se in a crucible in a high pressure atmosphere of inert gas to encapsulate the CuInSe.sub.2 melt and confine the Se to the crucible. Additional Se in the range of 1.8 to 2.2 percent over the stoichiometric quantity is preferred to make up for small amounts of Se lost in the process. The crystal is grown by inserting a seed crystal through the B.sub.2 O.sub.3 encapsulate into contact with the CuInSe.sub.2 melt and withdrawing the seed upwardly to grow the crystal thereon from the melt.

  13. Method of synthesizing and growing copper-indium-diselenide (CuInSe/sub 2/) crystals

    DOE Patents [OSTI]

    Ciszek, T.F.

    1984-11-29

    A process for preparing CuInSe/sub 2/ crystals includes melting a sufficient quantity of B/sub 2/O/sub 2/ along with stochiometric quantities of Cu, In, and Se in a crucible in a high-pressure atmosphere of inert gas to encapsulate the CuInSe/sub 2/ melt and confine the Se to the crucible. Additional Se in the range of 1.8 to 2.2% over the stochiometric quantity is preferred to make up for small amounts of Se lost in the process. The melt can then be cooled slowly to form the crystal as direct solidification, or the crystal can be grown by inserting a seed crystal through the B/sub 2/O/sub 3/ encapsulate into contact with the CuInSe/sub 2/ melt and withdrawing the seed upwardly to grow the crystal thereon from the melt.

  14. Pressure induced metallization with absence of structural transition in layered molybdenum diselenide

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

    Zhao, Zhao; Zhang, Haijun; Yuan, Hongtao; Wang, Shibing; Lin, Yu; Zeng, Qiaoshi; Xu, Gang; Liu, Zhenxian; Solanki, G. K.; Patel, K. D.; et al

    2015-06-19

    Layered transition-metal dichalcogenides have emerged as exciting material systems with atomically thin geometries and unique electronic properties. Pressure is a powerful tool for continuously tuning their crystal and electronic structures away from the pristine states. Here, we systematically investigated the pressurized behavior of MoSe2 up to ~60 GPa using multiple experimental techniques and ab-initio calculations. MoSe2 evolves from an anisotropic two-dimensional layered network to a three-dimensional structure without a structural transition, which is a complete contrast to MoS2. The role of the chalcogenide anions in stabilizing different layered patterns is underscored by our layer sliding calculations. MoSe2 possesses highly tunablemore » transport properties under pressure, determined by the gradual narrowing of its band-gap followed by metallization. The continuous tuning of its electronic structure and band-gap in the range of visible light to infrared suggest possible energy-variable optoelectronics applications in pressurized transition-metal dichalcogenides.« less

  15. Final Technical Report: Hawaii Hydrogen Center for Development and Deployment of Distributed Energy Systems

    SciTech Connect (OSTI)

    Rocheleau, Richard E.

    2008-09-30

    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

  16. 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.; Contreras, Miguel A.; Keane, James; Tennant, Andrew L.; Tuttle, John R.; Ramanathan, Kannan; Noufi, Rommel

    1998-03-24

    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.

  17. High Efficiency CdTe and CIGS Thin Film Solar Cells: Highlights...

    Office of Scientific and Technical Information (OSTI)

    Sponsoring Org: USDOE Country of Publication: United States Language: English Subject: 14 SOLAR ENERGY; 36 MATERIALS SCIENCE; EFFICIENCY; ENERGY CONVERSION; SOLAR CELLS; THIN FILMS ...

  18. Solid State Theory of Photovoltaic Materials: Nanoscale Grain Boundaries and Doping CIGS

    SciTech Connect (OSTI)

    Zunger, A

    2005-01-01

    We use modern first-principles electronic structure theory to investigate (1) why are grain boundaries in chalcopyrites passive; (2) can chalcopyrites be doped by transition metals, and; (3) can hot electrons and carrier multiplication be efficient in quantum-dot solar cells.

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

    SciTech Connect (OSTI)

    Not Available

    2014-08-01

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

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

    SciTech Connect (OSTI)

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

    2008-08-01

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

  1. PROJECT PROFILE: From Modules to Atoms: Increasing Reliability/Stability of Commercially Relevant Photovoltaic Technologies

    Broader source: Energy.gov [DOE]

    While there are statistical studies and macroscopic descriptions of module-level degradation, there is a lack of understanding of the structural, chemical, and electrical properties at the microscopic scale of how these processes occur and how to reduce or eliminate them. The project will study reliability-related defects in major photovoltaic (PV) technologies that include silicon (Si), cadmium telluride (CdTe), and copper indium gallium selenide (CIGS). Researchers will use imaging and microscopy characterization tools along with multi-physics modeling to derive the causes of power-limiting defects that are responsible for potential-induced degradation in Si, metastability and transient degradations in CdTe, and increased degradation due to reverse-bias breakdown in CIGS.

  2. Gallium composition dependence of crystallographic and thermoelectric properties in polycrystalline type-I Ba{sub 8}Ga{sub x}Si{sub 46-x} (nominal x=14-18) clathrates prepared by combining arc melting and spark plasma sintering methods

    SciTech Connect (OSTI)

    Anno, Hiroaki; JST, CREST, 5 Sanbancho, Chiyoda-ku, Tokyo 102-0075 ; Yamada, Hiroki; Nakabayashi, Takahiro; Hokazono, Masahiro; Shirataki, Ritsuko; JST, CREST, 5 Sanbancho, Chiyoda-ku, Tokyo 102-0075

    2012-09-15

    The gallium composition dependence of crystallographic and thermoelectric properties in polycrystalline n-type Ba{sub 8}Ga{sub x}Si{sub 46-x} (nominal x=14-18) compounds with the type-I clathrate structure is presented. Samples were prepared by combining arc melting and spark plasma sintering methods. Powder x-ray diffraction, Rietveld analysis, scanning electron microscopy, and energy-dispersive x-ray spectroscopy show that the solubility limit of gallium in the type-I clathrate phase is close to x=15, which is slightly higher than that for a single crystal. The carrier concentration at room temperature decreases from 2 Multiplication-Sign 10{sup 21} cm{sup -3} to 4 Multiplication-Sign 10{sup 20} cm{sup -3} as the Ga content x increases. The Seebeck coefficient, the electrical conductivity, and the thermal conductivity vary systematically with the carrier concentration when the Ga content x varies. The effective mass (2.0m{sub 0}), the carrier mobility (10 cm{sup 2} V{sup -1} s{sup -1}), and the lattice thermal conductivity (1.1 W m{sup -1} K{sup -1}) are determined for the Ga content x=14.51. The dimensionless thermoelectric figure of merit ZT is about 0.55 at 900 K for the Ga content x=14.51. The calculation of ZT using the experimentally determined material parameters predicts ZT=0.8 (900 K) at the optimum carrier concentration of about 2 Multiplication-Sign 10{sup 20} cm{sup -3}. - Graphical abstract: The gallium composition dependence of crystallographic and thermoelectric properties is presented on polycrystalline n-type Ba{sub 8}Ga{sub x}Si{sub 46-x} with the type-I clathrate structure prepared by combining arc melting and spark plasma sintering methods. The thermoelectric figure of merit ZT reaches 0.55 at 900 K due to the increase in the Ga content (close to x=15), and a calculation predicts further improvement of ZT at the optimized carrier concentration. Highlights: Black-Right-Pointing-Pointer Crystallographic properties of Ba{sub 8}Ga{sub x}Si{sub 46

  3. Superconductive silicon nanowires using gallium beam lithography.

    SciTech Connect (OSTI)

    Henry, Michael David; Jarecki, Robert Leo,

    2014-01-01

    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.

  4. 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, Ramn; Sitar, Zlatko; Irving, Douglas L.; Maria, Jon-Paul; Biegalski, Michael D.; Christen, Hans M.

    2014-02-14

    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.

  5. Enthalpy of formation of gallium nitride

    SciTech Connect (OSTI)

    Ranade, M.R.; Tessier, F.; Navrotsky, A.; Leppert, V.J.; Risbud, S.H.; DiSalvo, F.J.; Balkas, C.M.

    2000-05-04

    A major discrepancy in the literature concerning the enthalpy of formation of GaN has been resolved using oxidative oxide melt solution calorimetry. Four samples of differing nitrogen contents were measured by dropping them into molten 3Na{sub 2}O{center_dot}4MoO{sub 3} in a calorimeter at 975 K with oxygen gas bubbling through the solvent. The samples were characterized by X-ray diffraction, chemical analysis, transmission electron microscopy, particle size analysis, and BET measurements. The enthalpy of drop solution (kJ/g) varied approximately linearly with nitrogen content. Extrapolated to stoichiometric GaN, the data yield a value of {minus}156.8 {+-} 16.0 kJ/mol for the standard enthalpy of formation from the elements at 298 K. The relatively large error reflects the deviation of individual points from the straight line rather than uncertainties in each set of data for a given sample. This new directly measured enthalpy of formation is in excellent agreement with that obtained from the temperature dependence of the equilibrium pressure of nitrogen over GaN, {minus}157.7 kJ/mol, measured by Madar et al. and Karpinski and Porowski. This value of {minus}156.8 kJ/mol should replace the commonly tabulated value of {minus}110 kJ/mol determined by Hahn and Juza using combustion calorimetry on an uncharacterized sample over 50 years ago.

  6. Growth process for gallium nitride porous nanorods

    DOE Patents [OSTI]

    Wildeson, Isaac Harshman; Sands, Timothy David

    2015-03-24

    A GaN nanorod and formation method. Formation includes providing a substrate having a GaN film, depositing SiN.sub.x on the GaN film, etching a growth opening through the SiN.sub.x and into the GaN film, growing a GaN nanorod through the growth opening, the nanorod having a nanopore running substantially through its centerline. Focused ion beam etching can be used. The growing can be done using organometallic vapor phase epitaxy. The nanopore diameter can be controlled using the growth opening diameter or the growing step duration. The GaN nanorods can be removed from the substrate. The SiN.sub.x layer can be removed after the growing step. A SiO.sub.x template can be formed on the GaN film and the GaN can be grown to cover the SiO.sub.x template before depositing SiN.sub.x on the GaN film. The SiO.sub.x template can be removed after growing the nanorods.

  7. Thermophotovoltaic generators based on gallium antimonide

    SciTech Connect (OSTI)

    Khvostikov, V. P. Sorokina, S. V.; Potapovich, N. S.; Khvostikova, O. A.; Malievskaya, A. V.; Vlasov, A. S.; Shvarts, M. Z.; Timoshina, N. Kh.; Andreev, V. M.

    2010-02-15

    Designs of thermophotovoltaic (TPV) generators with infrared emitters heated by concentrated solar radiation are developed, fabricated, and tested. Emitters made of SiC, W, or Ta of various forms and sizes are studied. To the GaSb-based thermophotovoltaic cells, the efficiency of transformation of thermal radiation of W emitters was 19%. The features of operation of two variants of TPV generators, namely, of cylindrical and conical types, are considered. In a demonstration model of the TPV generator consisting of 12 photocells, the output electric power with conversion of the concentrated solar radiation was P = 3.8 W.

  8. 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.

    2012-10-15

    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

  9. Application of the bounds-analysis approach to arsenic and gallium antisite defects in gallium arsenide

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

    Wright, A. F.; Modine, N. A.

    2015-01-23

    The As antisite in GaAs (AsGa) has been the subject of numerous experimental and theoretical studies. Recent density-functional-theory (DFT) studies report results in good agreement with experimental data for the +2, +1, and 0 charge states of the stable EL2 structure, the 0 charge state of the metastable EL2* structure, and the activation energy to transform from EL2* to EL2 in the 0 charge state. However, these studies did not report results for EL2* in the -1 charge state. In this paper, we report new DFT results for the +2, +1, 0, and -1 charge states of AsGa, obtained usingmore » a semilocal exchange-correlation functional and interpreted using a bounds-analysis approach. In good agreement with experimental data, we find a -1/0 EL2* level 0.06 eV below the conduction-band edge and an activation energy of 0.05 eV to transform from EL2* to EL2 in the -1 charge state. While the Ga antisite in GaAs (GaAs) has not been studied as extensively as AsGa, experimental studies report three charge states (-2, -1, 0) and two levels (-2/-1, -1/0) close to the valence-band edge. Recent DFT studies report the same charge states, but the levels are found to be well-separated from the valence-band edge. To resolve this disagreement, we performed new DFT calculations for GaAs and interpreted them using a bounds analysis. The analysis identified the -1 and 0 charge states as hole states weakly bound to a highly-localized -2 charge state. Moreover, the -2/-1, -1/0 levels were found to be near the valence-band edge, in good agreement with the experimental data.« less

  10. Manufacturing technology development for CuInGaSe sub 2 solar cell modules

    SciTech Connect (OSTI)

    Stanbery, B.J. )

    1991-11-01

    The report describes research performed by Boeing Aerospace and Electronics under the Photovoltaic Manufacturing Technology project. We anticipate that implementing advanced semiconductor device fabrication techniques to the production of large-area CuIn{sub 1-x}Ga{sub x}Se{sub 2} (CIGS)/Cd{sub 1-y}Zn{sub y}S/ZnO monolithically integrated thin-film solar cell modules will enable 15% median efficiencies to be achieved in high-volume manufacturing. We do not believe that CuInSe{sub 2} (CIS) can achieve this efficiency in production without sufficient gallium to significantly increase the band gap, thereby matching it better to the solar spectrum (i.e., x{ge}0.2). Competing techniques for CIS film formation have not been successfully extended to CIGS devices with such high band gaps. The SERI-confirmed intrinsic stability of CIS-based photovoltaics renders them far superior to a-Si:H-based devices, making a 30-year module lifetime feasible. The minimal amounts of cadmium used in the structure we propose, compared to CdTe-based devices, makes them environmentally safer and more acceptable to both consumers and relevant regulatory agencies. Large-area integrated thin-film CIGS modules are the product most likely to supplant silicon modules by the end of this decade and enable the cost improvements which will lead to rapid market expansion.

  11. Photoelectrochemical solar cells based on d-band electrochemistry at transition metal diselenides. Technical progress report, first quarter, year one

    SciTech Connect (OSTI)

    Not Available

    1980-02-01

    Successful growth of WSe/sub 2/ crystals has led to the production of photocells which operate with greater than 5% monochromatic power converson efficiency in I/sup -//I/sub 2/ solution. Scanning light spot maps were used to identify and evaluate inhomogeneities across the surface and to serve as a reference for the edge passivation program which already has helped improve performance significantly. Results are discussed.

  12. This invention relates to methods of generating NP gallium nitride (GaN) across large areas (>1 cm.sup.2) with controlled pore diameters, pore density, and porosity. Also disclosed are methods of generating novel optoelectronic devices based on porous GaN. Additionally a layer transfer scheme to separate and create free-standing crystalline GaN thin layers is disclosed that enables a new device manufacturing paradigm involving substrate recycling. Other disclosed embodiments of this invention relate to fabrication of GaN based nanocrystals and the use of NP GaN electrodes for electrolysis, water splitting, or photosynthetic process applications.

    DOE Patents [OSTI]

    Zhang, Yu; Sun, Qian; Han, Jung

    2015-12-08

    This invention relates to methods of generating NP gallium nitride (GaN) across large areas (>1 cm.sup.2) with controlled pore diameters, pore density, and porosity. Also disclosed are methods of generating novel optoelectronic devices based on porous GaN. Additionally a layer transfer scheme to separate and create free-standing crystalline GaN thin layers is disclosed that enables a new device manufacturing paradigm involving substrate recycling. Other disclosed embodiments of this invention relate to fabrication of GaN based nanocrystals and the use of NP GaN electrodes for electrolysis, water splitting, or photosynthetic process applications.

  13. Absorptivity of semiconductors used in the production of solar cell panels

    SciTech Connect (OSTI)

    Kosyachenko, L. A. Grushko, E. V.; Mikityuk, T. I.

    2012-04-15

    The dependence of the absorptivity of semiconductors on the thickness of the absorbing layer is studied for crystalline silicon (c-Si), amorphous silicon (a-Si), cadmium telluride (CdTe), copper indium diselenide (CuInSe{sub 2}, CIS), and copper gallium diselenide (CuGaSe{sub 2}, CGS). The calculations are performed with consideration for the spectral distribution of AM1.5 standard solar radiation and the absorption coefficients of the materials. It is shown that, in the region of wavelengths {lambda} = {lambda}{sub g} = hc/E{sub g}, almost total absorption of the photons in AM1.5 solar radiation is attained in c-Si at the thickness d = 7-8 mm, in a-Si at d = 30-60 {mu}m, in CdTe at d = 20-30 {mu}m, and in CIS and CGS at d = 3-4 {mu}m. The results differ from previously reported data for these materials (especially for c-Si). In previous publications, the thickness needed for the semiconductor to absorb solar radiation completely was identified with the effective light penetration depth at a certain wavelength in the region of fundamental absorption for the semiconductor.

  14. NREL photovoltaic subcontract reports: Abstracts and document control information, 1 August 1991--31 July 1992

    SciTech Connect (OSTI)

    Not Available

    1992-08-01

    This report contains document control information and abstracts for the National Renewable Energy Laboratory (NREL) subcontracted photovoltaic program publications. It also lists source information on additional publications that describe US Department of Energy (DOE) PV research activities. It is not totally exhaustive, so it lists NREL contacts for requesting further information on the DOE and NREL PV programs. This report covers the period from August 1, 1991, through July 31, 1992. The purpose of continuing this type of publication is to help people keep abreast of specific PV interests, while maintaining a balance on the costs to the PV program. The information in this report is organized under PV technology areas: Amorphous silicon research; polycrystalline thin films (including copper indium diselenide, cadmium telluride, and thin-film silicon); crystalline materials and advanced concepts (including silicon, gallium arsenide, and other group III-V materials); and PV manufacturing technology development (which may include manufacturing information for various types of PV materials).

  15. Processing and Device Oriented Approach to CIGS Module Reliability; SunShot Initiative, U.S. Department of Energy (DOE)

    SciTech Connect (OSTI)

    Ramanathan, K.; Mansfield, L.; Garris, R.; Deline, C.; Silverman, T.

    2015-02-24

    Abstract: A device level understanding of thin film module reliability has been lacking. We propose that device performance and stability issues are strongly coupled and simultaneous attention to both is necessary. Commonly discussed technical issues such as light soaking, metastability, reverse bias breakdown and junction breakdown can be understood by comparing the behaviors of cells made inAbstract: A device level understanding of thin film module reliability has been lacking. We propose that device performance and stability issues are strongly coupled and simultaneous attention to both is necessary. Commonly discussed technical issues such as light soaking, metastability, reverse bias breakdown and junction breakdown can be understood by comparing the behaviors of cells made in the laboratory and industry. It will then be possible to attribute the observed effects in terms of processing and cell design. Process connection to stability studies can help identify root causes and a path for mitigating the degradation.

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

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

    of crystalline GaN growth in ESG Results and Accomplishments HRXRD vs reference SEM surface view 0 20 40 60 80 100 120 140 160 180 200 0 10 20 30 40 50 Deposition rate ...

  17. High-Quality, Low-Cost Bulk Gallium Nitride Substrates

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

    achieving GaN bulk growth without the limitations of tradi- tional crystal growth methods. ... MEMC technology transfer and marketing staff are coordinating with the research team to ...

  18. Fabrication and characterisation of gallium arsenide ambipolar quantum point contacts

    SciTech Connect (OSTI)

    Chen, J. C. H. Klochan, O.; Micolich, A. P.; Hamilton, A. R.; Das Gupta, K.; Sfigakis, F.; Ritchie, D. A.; Trunov, K.; Wieck, A. D.; Reuter, D.

    2015-05-04

    We show that ballistic one-dimensional channels can be formed in an ambipolar device fabricated on a high mobility Al{sub 0.34}Ga{sub 0.66}As/GaAs heterostructure. Both electron and hole quantised conductances can be measured in the same one-dimensional channel. We have used this device to compare directly the subband spacings of the two charge carriers in the same confining potential and used this to compare the electron and hole effective masses.

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

    SciTech Connect (OSTI)

    Patibandla, Nag; Agrawal, Vivek

    2012-12-01

    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.

  20. Size effects in the thermal conductivity of gallium oxide (β...

    Office of Scientific and Technical Information (OSTI)

    via this technique (8.8 3.4 W msup -1 Ksup -1) and large mean free paths compared ... with different metal transducers (Al, Au, and Au with a Ti wettingmore layer), we ...

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

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

    ways to exploit the novel properties that result are frontier areas of today's solid-state physics and materials science. However, before exploring and exploiting comes making....

  2. Convective Turbulence in Liquid Gallium and Sodium | Argonne...

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

    dynamics of the velocity field The figure displays streamlines of the two-dimensional skin friction field which was obtained right at the heated bottom plate of a cylindrical...

  3. Process for growing epitaxial gallium nitride and composite wafers

    DOE Patents [OSTI]

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

    2003-05-13

    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.

  4. Review of using gallium nitride for ionizing radiation detection

    SciTech Connect (OSTI)

    Wang, Jinghui; Mulligan, Padhraic; Cao, Lei R.; Brillson, Leonard

    2015-09-15

    With the largest band gap energy of all commercial semiconductors, GaN has found wide application in the making of optoelectronic devices. It has also been used for photodetection such as solar blind imaging as well as ultraviolet and even X-ray detection. Unsurprisingly, the appreciable advantages of GaN over Si, amorphous silicon (a-Si:H), SiC, amorphous SiC (a-SiC), and GaAs, particularly for its radiation hardness, have drawn prompt attention from the physics, astronomy, and nuclear science and engineering communities alike, where semiconductors have traditionally been used for nuclear particle detection. Several investigations have established the usefulness of GaN for alpha detection, suggesting that when properly doped or coated with neutron sensitive materials, GaN could be turned into a neutron detection device. Work in this area is still early in its development, but GaN-based devices have already been shown to detect alpha particles, ultraviolet light, X-rays, electrons, and neutrons. Furthermore, the nuclear reaction presented by {sup 14}N(n,p){sup 14}C and various other threshold reactions indicates that GaN is intrinsically sensitive to neutrons. This review summarizes the state-of-the-art development of GaN detectors for detecting directly and indirectly ionizing radiation. Particular emphasis is given to GaN's radiation hardness under high-radiation fields.

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

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

    Fabrication of initial 405 nm semipolar LEDs is based on high-IQE structures identified by the experimental data. View the Presentation 2014 BTO Peer Review Presentation - ...

  6. Review of using gallium nitride for ionizing radiation detection...

    Office of Scientific and Technical Information (OSTI)

    Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, Ohio 43210, USA, Department of Radiology, Stanford University, ...

  7. Traps identification in Copper-Indium-Gallium-Sulfur-Selenide...

    Office of Scientific and Technical Information (OSTI)

    Solar Cells Completed with Various Buffer Layers by Deep Level Transient Spectroscopy Current-voltage ... devices cells with high and low efficiencies were studied. ...

  8. Telio Solar Technologies Inc | Open Energy Information

    Open Energy Info (EERE)

    A CIGS start-up recently completed the construction of pilot line for manufacturing CIGS cell measuring 300 millimeters by 300. References: Telio Solar Technologies Inc1 This...

  9. Polycrystalline Thin Film Photovoltaics: Research, Development, and Technologies: Preprint

    SciTech Connect (OSTI)

    Ullal, H. S.; Zweibel, K.; von Roedern, B.

    2002-05-01

    II-VI binary thin-film solar cells based on cadmium telluride (CdTe) and I-III-VI ternary thin-film solar cells based on copper indium diselenide (CIS) and related materials have been the subject of intense research and development in the past few years. Substantial progress has been made thus far in the area of materials research, device fabrication, and technology development, and numerous applications based on CdTe and CIS have been deployed worldwide. World record efficiency of 16.5% has been achieved by NREL scientists for a thin-film CdTe solar cell using a modified device structure. Also, NREL scientists achieved world-record efficiency of 21.1% for a thin-film CIGS solar cell under a 14X concentration and AM1.5 global spectrum. When measured under a AM1.5 direct spectrum, the efficiency increases to 21.5%. Pathways for achieving 25% efficiency for tandem polycrystalline thin-film solar cells are elucidated. R&D issues relating to CdTe and CIS are reported in this paper, such as contact stability and accelerated life testing in CdTe, and effects of moisture ingress in thin-film CIS devices. Substantial technology development is currently under way, with various groups reporting power module efficiencies in the range of 7.0% to 12.1% and power output of 40.0 to 92.5 W. A number of lessons learned during the scale-up activities of the technology development for fabrication of thin-film power modules are discussed. The major global players actively involved in the technology development and commercialization efforts using both rigid and flexible power modules are highlighted.

  10. Photovoltaic manufacturing: Present status, future prospects, and research needs

    SciTech Connect (OSTI)

    Wolden, C.A.; Fthenakis, V.; Kurtin, J.; Baxter, J.; Repins, I.; Shasheen, S.; Torvik, J.; Rocket, A.; Aydil, E.

    2011-03-29

    In May 2010 the United States National Science Foundation sponsored a two-day workshop to review the state-of-the-art and research challenges in photovoltaic (PV) manufacturing. This article summarizes the major conclusions and outcomes from this workshop, which was focused on identifying the science that needs to be done to help accelerate PV manufacturing. A significant portion of the article focuses on assessing the current status of and future opportunities in the major PV manufacturing technologies. These are solar cells based on crystalline silicon (c-Si), thin films of cadmium telluride (CdTe), thin films of copper indium gallium diselenide, and thin films of hydrogenated amorphous and nanocrystalline silicon. Current trends indicate that the cost per watt of c-Si and CdTe solar cells are being reduced to levels beyond the constraints commonly associated with these technologies. With a focus on TW/yr production capacity, the issue of material availability is discussed along with the emerging technologies of dye-sensitized solar cells and organic photovoltaics that are potentially less constrained by elemental abundance. Lastly, recommendations are made for research investment, with an emphasis on those areas that are expected to have cross-cutting impact.

  11. Plasma-Assisted Coevaporation of S and Se for Wide Band Gap Chalcopyrite Photovoltaics: Phase II Annual Report, December 2002--December 2003

    SciTech Connect (OSTI)

    Repins, I.; Wolden, C.

    2004-01-01

    In this work, ITN Energy Systems (ITN) and lower-tier subcontractor Colorado School of Mines (CSM) explore the replacement of the molecular chalcogen precursors during deposition (e.g., Se2 or H2Se) with more reactive chalcogen monomers or radicals (e.g., Se). Molecular species are converted to atomic species in a low-pressure inductively coupled plasma (ICP). Tasks of the proposed program center on development and validation of monatomic chalcogen chemistry, tuning of low-pressure monomer chalcogen sources, and evaluation of plasma-assisted co-evaporation (PACE) for CIGS co-evaporation. Likely advantages of deposition by plasma-enhanced co-evaporation include: (1) Providing potential for lower deposition temperature and/or for better film quality at higher deposition temperature. (2) Providing potential for decreased deposition times. (3) Providing high material utilization efficiency ({approx}90%) that results in less deposition on other parts of the reactor, leading to lower clean up and maintenance costs, as well as longer equipment lifetime. High material utilization efficiency also reduces the total operating pressure, which is beneficial for the design and control of metal co-evaporation. Advantages include minimal metal-vapor beam spread and lower source operating temperatures. (4) Enabling deposition of wide-bandgap copper indium gallium disulfur-selenide (CIGSS) films with controlled stoichiometry. University researchers at CSM are developing and testing the fundamental chemistry and engineering principles. Industrial researchers at ITN are adapting PACE technology to CIGSS co-evaporation and validating PACE process for fabrication of thin-film photovoltaics. In2Se3 films, which are used as precursor layers in high-efficiency CIGS depositions, were used this year as the first test case for examining the advantages of PACE listed above. Gradually, the investigation is being extended to the complete high-efficiency three-stage co-evaporation process.

  12. Microsoft Word - NY17-15 01-50.rtf

    Office of Legacy Management (LM)

    of their employees, nor any of their contractors, subcontractors, or their employees, ... (pCig) above background a,b,c Radium-266 5 pCig, averaged over the first 15 ...

  13. Photovoltaic Cell Material Basics | Department of Energy

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

    Silicon (Si)-including single-crystalline Si, multicrystalline Si, and amorphous Si Polycrystalline Thin Films-including copper indium diselenide (CIS), cadmium telluride (CdTe), ...

  14. Structural and morphological evolution of gallium nitride nanorods grown by chemical beam epitaxy

    SciTech Connect (OSTI)

    Kuo, Shou-Yi; Lai, Fang-I; Chen, Wei-Chun; Hsiao, Chien-Nan; Lin, Woei-Tyng

    2009-07-15

    The morphological and structural evolution is presented for GaN nanorods grown by chemical beam epitaxy on (0001) Al{sub 2}O{sub 3} substrates. Their structural and optical properties are investigated by x-ray diffraction, scanning and transmission electron microscopy, and temperature-dependent photoluminescence measurements. While increasing the growth temperature and the flow rate of radio-frequency nitrogen radical, the three-dimensional growth mode will be enhanced to form one-dimensional nanostructures. The high density of well-aligned nanorods with a diameter of 30-50 nm formed uniformly over the entire sapphire substrate. The x-ray diffraction patterns and transmission electron microscopic images indicate that the self-assembled GaN nanorods are a pure single crystal and preferentially oriented in the c-axis direction. Particularly, the ''S-shape'' behavior with localization of {approx}10 meV observed in the temperature-dependent photoluminescence might be ascribed to the fluctuation in crystallographic defects and composition.

  15. Measurement of piezoelectric constants of lanthanum-gallium tantalate crystal by X-ray diffraction methods

    SciTech Connect (OSTI)

    Blagov, A. E.; Marchenkov, N. V. Pisarevsky, Yu. V.; Prosekov, P. A.; Kovalchuk, M. V.

    2013-01-15

    A method for measuring piezoelectric constants of crystals of intermediate systems by X-ray quasi-multiple-wave diffraction is proposed and implemented. This technique makes it possible to determine the piezoelectric coefficient by measuring variations in the lattice parameter under an external electric field. This method has been approved, its potential is evaluated, and a comparison with high-resolution X-ray diffraction data is performed.

  16. Elastic scattering by hot electrons and apparent lifetime of longitudinal optical phonons in gallium nitride

    SciTech Connect (OSTI)

    Khurgin, Jacob B.; Bajaj, Sanyam; Rajan, Siddharth

    2015-12-28

    Longitudinal optical (LO) phonons in GaN generated in the channel of high electron mobility transistors (HEMT) are shown to undergo nearly elastic scattering via collisions with hot electrons. The net result of these collisions is the diffusion of LO phonons in the Brillouin zone causing reduction of phonon and electron temperatures. This previously unexplored diffusion mechanism explicates how an increase in electron density causes reduction of the apparent lifetime of LO phonons, obtained from the time resolved Raman studies and microwave noise measurements, while the actual decay rate of the LO phonons remains unaffected by the carrier density. Therefore, the saturation velocity in GaN HEMT steadily declines with increased carrier density, in a qualitative agreement with experimental results.

  17. Accelerated Testing of HT-9 with Zirconia Coatings Containing Gallium using Raman Spectroscopy and XPS

    SciTech Connect (OSTI)

    Windisch, Charles F.; Henager, Charles H.; Engelhard, Mark H.; Bennett, Wendy D.

    2009-12-01

    Laser Raman spectroscopy and x-ray photoelectron spectroscopy were used to study the evolution of composition of oxide films in the presence of zirconia coatings on miniature HT-9 alloy specimens subjected to elevated temperature in air. The experiments expanded on previous efforts to develop a quick-screening technique for candidate alloys for cladding materials (HT-9) and actinide-based mixed oxide fuel mixtures (represented by the zirconia coating) by investigating the effect of both coating composition and alloy pretreatment conditions on the high temperature reactions. In particular, the presence of the element Ga (a potential impurity in mixed oxide fuel) in the initial zirconia coating was found to accelerate the rate of oxide growth relative to that of yttria-stabilized zirconia studied previously. In addition, HT-9 samples that were subjected to different thermal pretreatments gave different results. The results suggest that the presence of Ga in a mixed oxide fuel will enhance the corrosion of HT-9 cladding under the conditions of this study, although the extent of enhancement is influenced by thermal pretreatment of the cladding material. The results also demonstrate the need to combine Raman spectroscopy with other techniques, particularly photoelectron spectroscopy, for optimizing composition and/or fabrication conditions of both cladding and oxide fuels for advanced nuclear reactors.

  18. 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

  19. Application of the bounds-analysis approach to arsenic and gallium...

    Office of Scientific and Technical Information (OSTI)

    Date: 2015-01-01 OSTI Identifier: 1235253 Report Number(s): SAND2014-17327J Journal ID: ISSN 1098-0121; PRBMDO; 537237 GrantContract Number: AC04-94AL85000 Type: Accepted...

  20. Lateral damage in graphene carved by high energy focused gallium ion beams

    SciTech Connect (OSTI)

    Liao, Zhongquan; Zhang, Tao; Jordan, Rainer; Gall, Martin; Rosenkranz, Rüdiger; Dianat, Arezoo; Cuniberti, Gianaurelio; and others

    2015-07-06

    Raman mapping is performed to study the lateral damage in supported monolayer graphene carved by 30 keV focused Ga{sup +} beams. The evolution of the lateral damage is tracked based on the profiles of the intensity ratio between the D (1341 cm{sup −1}) and G (1582 cm{sup −1}) peaks (I{sub D}/I{sub G}) of the Raman spectra. The I{sub D}/I{sub G} profile clearly reveals the transition from stage 2 disorder into stage 1 disorder in graphene along the direction away from the carved area. The critical lateral damage distance spans from <1 μm up to more than 30 μm in the experiment, depending on the parameters used for carving the graphene. The wide damage in the lateral direction is attributed to the deleterious tail of unfocused ions in the ion beam probe. The study raises the attention on potential sample damage during direct patterning of graphene nanostructures using the focused ion beam technique. Minimizing the total carving time is recommended to mitigate the lateral damage.

  1. Calculation of infrared plasma reflection spectra of inhomogeneously doped P-type gallium arsenide

    SciTech Connect (OSTI)

    CHEN Wei-xi; LI Guo-hua; NIU Jin-zhen; GUO Chang-zhi

    1982-01-01

    The influence of the surface concentration and concentration profile of free carriers, the layer thickness and free carrier concentration of the homogeneous substrate on the infrared plasma reflection spectra of inhomogeneously doped P-type GaAs layers is analyzed by computer solutions of differential equations for the optical admittance. Computed spectra are reported for four different profiles and several substrate concentrations. Methods for evaluation of the measured reflection spectra and the limitation of this technique are discussed.

  2. Sandia Demonstrated First-Time, Single-Mode Lasing in Gallium...

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

    Transportation Energy Consortiums Engine Combustion Facilities Algae Testbed Battery Abuse ... in George's work is an important step toward all nanowire-laser-based applications. ...

  3. The Russian-American Gallium Experiment (SAGE) Cr Neutrino Source Measurement

    SciTech Connect (OSTI)

    Abdurashitov, J.; Gavrin, V.; Girin, S.; Gorbachev, V.; Ibragimova, T.; Kalikhov, A.; Khairnasov, N.; Knodel, T.; Kornoukhov, V.; Mirmov, I.; Shikhin, A.; Veretenkin, E.; Vermul, V.; Yants, V.; Zatsepin, G.; Bowles, T.; Nico, J.; Teasdale, W.; Wark, D.; Cherry, M.; Karaulov, V.; Levitin, V.; Maev, V.; Nazarenko, P.; Shkolnik, V.; Skorikov, N.; Cleveland, B.; Daily, T.; Davis, R. Jr.; Lande, K.; Lee, C.; Wildenhain, P.; Khomyakov, Y.; Zvonarev, A.; Elliott, S.; Wilkerson, J.

    1996-12-01

    The solar neutrino capture rate measured by SAGE is well below that predicted by solar models. To check the overall experimental efficiency, we exposed 13tonnes of Ga metal to a reactor-produced 517kCi source of {sup 51}Cr. The ratio of the measured production rate to that predicted from the source activity is 0.95{plus_minus}0.11(stat)+0.05/{minus}0.08(syst). This agreement verifies that the experimental efficiency is measured correctly, establishes that there are no unknown systematic errors at the 10{percent} level, and provides considerable evidence for the reliability of the solar neutrino measurement. {copyright} {ital 1996 The American Physical Society.}

  4. Fluorescent lifetime measurements of rare-earth elements in gallium arsenide. Master's thesis

    SciTech Connect (OSTI)

    Topp, D.J.

    1990-12-01

    Lifetime measurements of the excited states of three GaAs semiconductors doped with the rare earth elements Erbium (Er), Praseodymium (Pr), and Thulium (Tm) has been studied using a pulsed nitrogen laser and germanium detector. The measurements were made with an experimental set up with a system response time of 0.34 microseconds. A 330 milliwatt nitrogen laser with a wavelength of 3370 angstroms was used to excite transitions of the rare earth elements.

  5. 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

    2002-01-30

    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.

  6. Electron emitting device and method of making the same

    DOE Patents [OSTI]

    Olsen, Gregory Hammond; Martinelli, Ramon Ubaldo; Ettenberg, Michael

    1977-04-19

    A substrate of single crystalline gallium arsenide has on a surface thereof a layer of single crystalline indium gallium phosphide. A layer of single crystalline gallium arsenide is on the indium gallium phosphide layer and a work function reducing material is on the gallium arsenide layer. The substrate has an opening therethrough exposing a portion of the indium gallium phosphide layer.

  7. Plasma-Assisted Coevaporation of S and Se for Wide Band Gap Chalcopyrite Photovoltaics: Phase I Annual Report; December 2001-December 2002

    SciTech Connect (OSTI)

    Repins, I.; Wolden, C.

    2003-01-01

    In this work, ITN Energy Systems (ITN) and lower-tier subcontractor Colorado School of Mines (CSM) explore the replacement of the molecular chalcogen precursors during deposition (e.g., Se2 or H2Se) with more reactive chalcogen monomers or radicals (e.g., Se). Molecular species will be converted to atomic species in a low-pressure inductively coupled plasma. The non-equilibrium environment created by the plasma will allow control over the S/Se ratio in these films. Tasks of the proposed program center on developing and validating monoatomic chalcogen chemistry, tuning of low-pressure monomer chalcogen sources, and evaluating plasma-assisted coevaporation (PACE) for CIGS coevaporation. Likely advantages of deposition by plasma-enhanced coevaporation include: (a)provides potential for lower deposition temperature and/or for better film quality at higher deposition temperature; (b) provide potential for decreased deposition times; (c) provides high material utilization efficiency ({approx}90%) that results in less deposition on other parts of the reactor, leading to lower clean-up and maintenance costs, as well as longer equipment lifetime; (d) high material utilization efficiency also reduces the total operating pressure, which is beneficial for the design and control of metal coevaporation (advantages include minimal metal-vapor beam spread and lower source operating temperatures); (e) enables deposition of wide-bandgap copper indium gallium sulfur-selenide (CIGSS) films with controlled stoichiometry.

  8. CIBS Solar Cell Development Final Scientific/Technical Report

    SciTech Connect (OSTI)

    Exstrom, Christopher L.; Soukup, Rodney J.; Ianno, Natale J.

    2011-09-28

    Efforts to fabricate and study a new photovoltaic material, copper indium boron diselenide (CuInxB1-xSe2 or CIBS), were undertaken. Attempts to prepare CIBS using sputtering deposition techniques resulted in segregation of boron from the rest of elements in the material. CIBS nanocrystals were prepared from the reaction of elemental Se with CuCl, InCl3, and boric acid in solution, but the product material quickly decomposed upon heating that was required in attempts to convert the nanocrystals into a thin film. The investigation of the reasons for the lack of CIBS material stability led to new structure-property studies of closely-related photovoltaic systems as well as studies of new solar cell materials and processing methods that could enhance the development of next-generation solar technologies. A detailed compositional study of CuIn1-xAlxSe2 (CIAS, a system closely related to CIBS) revealed a non-linear correlation between crystal lattice size and the Al/(In+Al) ratios with dual-phase formation being observed. A new nanocrystal-to-thin-film processing method was developed for the preparation of CuIn1-xGaxSe2 (CIGS) thin films in which colloidal Se particles are sprayed in contact with CuIn1-xGaxS2 nanoparticles and heated in an argon atmosphere with no other Se source in the system. The process is non-vacuum and does not require toxic gases such as Se vapor or H2Se. Expertise gained from these studies was applied to new research in the preparation of thin-film pyrite FeS2, an attractive earth-abundant candidate material for next-generation photovoltaics. Three methods successfully produced pure pyrite FeS2 films: sulfurization of sputtered Fe films, chemical bath deposition, and sulfurization of Fe2O3 sol-gel precursors. The last method produced pinhole-free films that may be viable for device development. Nickel, platinum, and possibly carbon would appear to serve as good ohmic contact materials. While CdS has a reasonable conduction band energy match to

  9. DESIGN AND ANALYSIS OF AN INTEGRATED PULSE MODULATED S-BAND POWER AMPLIFIER IN GALLIUM NITRIDE PROCESS

    SciTech Connect (OSTI)

    STEVE SEDLOCK

    2012-04-04

    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.

  10. Boron, bismuth co-doping of gallium arsenide and other compounds for photonic and heterojunction bipolar transistor devices

    DOE Patents [OSTI]

    Mascarenhas, Angelo

    2015-07-07

    Isoelectronic co-doping of semiconductor compounds and alloys with acceptors and deep donors is sued to decrease bandgap, to increase concentration of the dopant constituents in the resulting alloys, and to increase carrier mobilities lifetimes. For example, Group III-V compounds and alloys, such as GaAs and GaP, are isoelectronically co-doped with, for example, B and Bi, to customize solar cells, and other semiconductor devices. Isoelectronically co-doped Group II-VI compounds and alloys are also included.

  11. HIGH-QUALITY, LOW-COST BULK GALLIUM NITRIDE SUBSTRATES GROWN BY THE ELECTROCHEMICAL SOLUTION GROWTH METHOD

    Broader source: Energy.gov [DOE]

    To develop ESG into a viable bulk growth process for GaN that is more scalable to large-area wafer manufacturing and able to produce cost-effective, high-quality bulk GaN substrates.

  12. Direct synthesis of large area graphene on insulating substrate by gallium vapor-assisted chemical vapor deposition

    SciTech Connect (OSTI)

    Murakami, Katsuhisa Hiyama, Takaki; Kuwajima, Tomoya; Fujita, Jun-ichi; Tanaka, Shunsuke; Hirukawa, Ayaka; Kano, Emi; Takeguchi, Masaki

    2015-03-02

    A single layer of graphene with dimensions of 20?mm??20?mm was grown directly on an insulating substrate by chemical vapor deposition using Ga vapor catalysts. The graphene layer showed highly homogeneous crystal quality over a large area on the insulating substrate. The crystal quality of the graphene was measured by Raman spectroscopy and was found to improve with increasing Ga vapor density on the reaction area. High-resolution transmission electron microscopy observations showed that the synthesized graphene had a perfect atomic-scale crystal structure within its grains, which ranged in size from 50?nm to 200?nm.

  13. 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; Shivaraman, Ravi; Speck, James S.

    2014-09-21

    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.

  14. Atomic Resolution in Situ Imaging of a Double-Bilayer Multistep Growth Mode in Gallium Nitride Nanowires

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

    Gamalski, A. D.; Tersoff, J.; Stach, E. A.

    2016-04-13

    We study the growth of GaN nanowires from liquid Au–Ga catalysts using environmental transmission electron microscopy. GaN wires grow in either (11¯20) or (11¯00) directions, by the addition of {11¯00} double bilayers via step flow with multiple steps. Step-train growth is not typically seen with liquid catalysts, and we suggest that it results from low step mobility related to the unusual double-height step structure. Finally, the results here illustrate the surprising dynamics of catalytic GaN wire growth at the nanoscale and highlight striking differences between the growth of GaN and other III–V semiconductor nanowires.

  15. Role of self-trapped holes in the photoconductive gain of β-gallium oxide Schottky diodes

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

    Armstrong, Andrew M.; Crawford, Mary H.; Jayawardena, Asanka; Ahyi, Ayayi; Dhar, Sarit

    2016-03-10

    Solar-blind photodetection and photoconductive gain > 50 corresponding to a responsivity > 8 A/W was observed for β-Ga2O3 Schottky photodiodes. We investigated the origin of photoconductive gain. Current-voltage characteristics of the diodes did not indicate avalanche breakdown, which excludes carrier multiplication by impact ionization as the source for gain. However, photocapacitance measurements indicated a mechanism for hole localization for above-band gap illumination, suggesting self-trapped hole formation. Comparison of photoconductivity and photocapacitance spectra indicated that self-trapped hole formation coincides with the strong photoconductive gain. We conclude that self-trapped hole formation near the Schottky diode lowers the effective Schottky barrier in reversemore » bias, producing photoconductive gain. Ascribing photoconductive gain to an inherent property like self-trapping of holes can explain the operation of a variety of β-Ga2O3 photodetectors.« less

  16. Solarion AG | Open Energy Information

    Open Energy Info (EERE)

    Germany Zip: 4288 Sector: Solar Product: Focuses on the development, production and marketing of CIGS thin-film solar cells on flexible substrate. References: Solarion AG1 This...

  17. Applied Quantum Technology AQT | Open Energy Information

    Open Energy Info (EERE)

    Quantum Technology AQT Jump to: navigation, search Name: Applied Quantum Technology (AQT) Place: Santa Clara, California Zip: 95054 Product: California-based manufacturer of CIGS...

  18. Honda Soltec Co Ltd | Open Energy Information

    Open Energy Info (EERE)

    Ltd Jump to: navigation, search Name: Honda Soltec Co Ltd Place: Kikuchi-gun, Kumamoto, Japan Sector: Solar Product: Japanese distributor of Honda Engineering's CIGS thin-film...

  19. Two Principles For Clean-Energy Policy | Department of Energy

    Energy Savers [EERE]

    scale advantages, "old" polysilicon technology has been more competitive than a range of newer technologies, including CadTel, CIGS, thin film amorphous Si, CSP, and solar thermal. ...

  20. Optical Method for Automated Real Time Control of Elemental Compositio...

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

    Optical Method for Automated Real Time Control of Elemental Composition, Distribution, and Film Thickness in CIGS Solar Cell Production National Renewable Energy Laboratory Contact ...

  1. GreenStone Technologies LLC | Open Energy Information

    Open Energy Info (EERE)

    Name: GreenStone Technologies LLC Place: Wisconsin Zip: 53719 Product: Developing a copper indium hallium selenide (CIGS) thin-film PV technology, also performs custom contract...

  2. Ascent Solar Technologies Inc | Open Energy Information

    Open Energy Info (EERE)

    Sector: Solar Product: Ascent Solar develops and plans to manufacture CIGS thin-film solar cells and modules for the satellite and high-altitude airship (HAA)...

  3. ScanningTunneling Luminescence of Grain Boundaries in Cu(In,Ga)Se2

    SciTech Connect (OSTI)

    Romero, M. J.; Jiang, C.-S.; Al-Jassim, M. M.; Noufi, R.

    2005-01-01

    At the Laboratory, photon emission in semiconductors has been mapped in the nanoscale using scanning tunneling microscopy (STM). In this Solar Program Review Meeting, we report on the latest results obtained in Cu(In,Ga)Se2 (CIGS) thin films by this adapted STM. Scanning tunneling luminescence (STL) spectroscopy suggests that photons are emitted near the surface of CIGS. STL is excited either by (1) diffusion of tunneling electrons and subsequent recombination with available holes in CIGS or (2) impact ionization by hot electrons. Which process becomes predominant depends on the voltage applied to the STM tip. Photon mapping shows electronically active, extended defects near the surface of CIGS thin films.

  4. PVNext Corporation | Open Energy Information

    Open Energy Info (EERE)

    to: navigation, search Name: PVNext Corporation Place: Taiwan Product: Taiwan-based CIGS thin-film PV module manufacturer. References: PVNext Corporation1 This article is a...

  5. Shandong Sunvim Solar Technology Co Ltd | Open Energy Information

    Open Energy Info (EERE)

    Technology Co Ltd Place: Shandong Province, China Product: Chinese manufacturer of CIGS thin film PV project. References: Shandong Sunvim Solar Technology Co Ltd1 This article...

  6. Unionmet Singapore Limited | Open Energy Information

    Open Energy Info (EERE)

    Place: Singapore Zip: 68805 Product: A manufacturer and recycler of indium - a raw material for CIGS PV and also for most transparent conducting oxides. References: Unionmet...

  7. DayStar Technologies Inc | Open Energy Information

    Open Energy Info (EERE)

    Technologies Inc Jump to: navigation, search Name: DayStar Technologies Inc Place: Santa Clara, California Zip: 95054 Product: US-based manufacturer of CIGS cells and modules....

  8. Miasole Inc | Open Energy Information

    Open Energy Info (EERE)

    Miasole Inc Jump to: navigation, search Name: Miasole Inc Place: Santa Clara, California Zip: 95051 Sector: Solar Product: California-based manufacturer of CIGS thin-film solar...

  9. Nanowin Technology Co Ltd | Open Energy Information

    Open Energy Info (EERE)

    Co Ltd Place: Tainan County, Taiwan Zip: 741 Sector: Solar Product: Taiwan-based CIGS solar cell turnkey solution provider. References: Nanowin Technology Co Ltd1 This...

  10. Photovoltaic Single-Crystalline, Thin-Film Cell Basics

    Broader source: Energy.gov [DOE]

    Single-crystalline thin films are made from gallium arsenide (GaAs), a compound semiconductor that is a mixture of gallium and arsenic.

  11. Flexible, transparent thin film transistors raise hopes for flexible...

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

    of the thin-film transistor, fabricated using single-atom-thick layers of graphene and tungsten diselenide, among other materials. The white scale bar shows 5 microns, which is...

  12. Cadmium-free junction fabrication process for CuInSe.sub.2 thin film solar cells

    DOE Patents [OSTI]

    Ramanathan, Kannan V.; Contreras, Miguel A.; Bhattacharya, Raghu N.; Keane, James; Noufi, Rommel

    1999-01-01

    The present invention provides an economical, simple, dry and controllable semiconductor layer junction forming process to make cadmium free high efficiency photovoltaic cells having a first layer comprised primarily of copper indium diselenide having a thin doped copper indium diselenide n-type region, generated by thermal diffusion with a group II(b) element such as zinc, and a halide, such as chlorine, and a second layer comprised of a conventional zinc oxide bilayer. A photovoltaic device according the present invention includes a first thin film layer of semiconductor material formed primarily from copper indium diselenide. Doping of the copper indium diselenide with zinc chloride is accomplished using either a zinc chloride solution or a solid zinc chloride material. Thermal diffusion of zinc chloride into the copper indium diselenide upper region creates the thin n-type copper indium diselenide surface. A second thin film layer of semiconductor material comprising zinc oxide is then applied in two layers. The first layer comprises a thin layer of high resistivity zinc oxide. The second relatively thick layer of zinc oxide is doped to exhibit low resistivity.

  13. ABBREVIATIONS AND ACRONYMS AEC U.S. Atomic Energy Commission

    Office of Legacy Management (LM)

    ... Sample Location Sample Total Uranium (pCig) Error (pCig) SL-1 M6L101 0.9 0.4 SL-2 ... Limit Result Error Detection Limit SL-1 M6L101 Grab 0.5 0.3 0.2 0.0 0.0 0.2 0.4 ...

  14. 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.

    2011-09-01

    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.

  15. Beyond Silicon: Cutting the Costs of Solar Power

    DOE R&D Accomplishments [OSTI]

    Ahlberg, Liz

    2011-04-15

    New method of fabricating semiconductors from gallium arsenide promises more affordable solar power, improved semiconductor devices.

  16. Final Report for Department of Energy/EERE (for public release)

    SciTech Connect (OSTI)

    Yi Cui

    2012-04-30

    Developing CIGS solar cells calls for the understanding of materials and processing in order to translate the record small efficiency to module and the strategy to produce thin cells for materials and processing saving. This project has exploited nanostructuring of CIG solar cells, including nanowires and nanotextured substrates. We showed that nanowires function as well-defined CIGS-CdS p-n junction for understanding the chemical fluctuation, defect formation interface and grain boundary behaviors and the effect of ion diffusion, which are important but complicated issues for solar cell fabrication. We have also demonstrated effective nanoscale photon management on nanotextured substrate to provide opportunity for thin CIGS solar cells. We also developed the scalable methods for producing such nanotextured substrates. The research output in this project helps advancing the CIGS solar cells and broadly other solar cell technologies in cost reduction per unit power.

  17. Method for the chemical separation of GE-68 from its daughter Ga-68

    DOE Patents [OSTI]

    Fitzsimmons, Jonathan M.; Atcher, Robert W.

    2010-06-01

    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.

  18. Reducing interface recombination for Cu(In,Ga)Se{sub 2} by atomic layer deposited buffer layers

    SciTech Connect (OSTI)

    Hultqvist, Adam; Bent, Stacey F.; Li, Jian V.; Kuciauskas, Darius; Dippo, Patricia; Contreras, Miguel A.; Levi, Dean H.

    2015-07-20

    Partial CuInGaSe{sub 2} (CIGS) solar cell stacks with different atomic layer deposited buffer layers and pretreatments were analyzed by photoluminescence (PL) and capacitance voltage (CV) measurements to investigate the buffer layer/CIGS interface. Atomic layer deposited ZnS, ZnO, and SnO{sub x} buffer layers were compared with chemical bath deposited CdS buffer layers. Band bending, charge density, and interface state density were extracted from the CV measurement using an analysis technique new to CIGS. The surface recombination velocity calculated from the density of interface traps for a ZnS/CIGS stack shows a remarkably low value of 810 cm/s, approaching the range of single crystalline II–VI systems. Both the PL spectra and its lifetime depend on the buffer layer; thus, these measurements are not only sensitive to the absorber but also to the absorber/buffer layer system. Pretreatment of the CIGS prior to the buffer layer deposition plays a significant role on the electrical properties for the same buffer layer/CIGS stack, further illuminating the importance of good interface formation. Finally, ZnS is found to be the best performing buffer layer in this study, especially if the CIGS surface is pretreated with potassium cyanide.

  19. Rare-earth transition-metal gallium chalcogenides RE{sub 3}MGaCh{sub 7} (M=Fe, Co, Ni; Ch=S, Se)

    SciTech Connect (OSTI)

    Rudyk, Brent W.; Stoyko, Stanislav S.; Oliynyk, Anton O.; Mar, Arthur

    2014-02-15

    Six series of quaternary rare-earth transition-metal chalcogenides RE{sub 3}MGaCh{sub 7} (M=Fe, Co, Ni; Ch=S, Se), comprising 33 compounds in total, have been prepared by reactions of the elements at 1050 °C (for the sulphides) or 900 °C (for the selenides). They adopt noncentrosymmetric hexagonal structures (ordered Ce{sub 3}Al{sub 1.67}S{sub 7}-type, space group P6{sub 3}, Z=2) with cell parameters in the ranges of a=9.5–10.2 Å and c=6.0–6.1 Å for the sulphides and a=10.0–10.5 Å and c=6.3–6.4 Å for the selenides as refined from powder X-ray diffraction data. Single-crystal structures were determined for five members of the sulphide series RE{sub 3}FeGaS{sub 7} (RE=La, Pr, Tb) and RE{sub 3}CoGaS{sub 7} (RE=La, Tb). The highly anisotropic crystal structures consist of one-dimensional chains of M-centred face-sharing octahedra and stacks of Ga-centred tetrahedra all pointing in the same direction. Magnetic measurements on the sulphides reveal paramagnetic behaviour in some cases and long-range antiferromagnetic behaviour with low Néel temperatures (15 K or lower) in others. Ga L-edge XANES spectra support the presence of highly cationic Ga tetrahedral centres with a tendency towards more covalent Ga–Ch character on proceeding from the sulphides to the selenides. Band structure calculations on La{sub 3}FeGaS{sub 7} indicate that the electronic structure is dominated by Fe 3d-based states near the Fermi level. - Graphical abstract: The series of chalcogenides RE{sub 3}MGaS{sub 7}, which form for a wide range of rare-earth and transition metals (M=Fe, Co, Ni), adopt highly anisotropic structures containing chains of M-centred octahedra and stacks of Ga-centred tetrahedra. Display Omitted - Highlights: • Six series (comprising 33 compounds) of chalcogenides RE{sub 3}MGaCh{sub 7} were prepared. • They adopt noncentrosymmetric hexagonal structures with high anisotropy. • Most compounds are paramagnetic; some show antiferromagnetic ordering. • Ga L-edge XANES confirms presence of cationic Ga species.

  20. Noncentrosymmetric rare-earth copper gallium chalcogenides RE{sub 3}CuGaCh{sub 7} (RE=La–Nd; Ch=S, Se): An unexpected combination

    SciTech Connect (OSTI)

    Iyer, Abishek K.; Rudyk, Brent W.; Lin, Xinsong; Singh, Harpreet; Sharma, Arzoo Z.; Wiebe, Christopher R.; Mar, Arthur

    2015-09-15

    The quaternary rare-earth chalcogenides RE{sub 3}CuGaS{sub 7} and RE{sub 3}CuGaSe{sub 7} (RE=La–Nd) have been prepared by reactions of the elements at 1050 °C and 900 °C, respectively. They crystallize in the noncentrosymmetric La{sub 3}CuSiS{sub 7}-type structure (hexagonal, space group P6{sub 3}, Z=2) in which the a-parameter is largely controlled by the RE component (a=10.0–10.3 Å for the sulfides and 10.3–10.6 Å for the selenides) whereas the c-parameter is essentially fixed by the choice of Ga and chalcogen atoms within tetrahedral units (c=6.1 Å for the sulfides and 6.4 Å for the selenides). They extend the series RE{sub 3}MGaCh{sub 7}, previously known for divalent metal atoms (M=Mn–Ni), differing in that the Cu atoms in RE{sub 3}CuGaCh{sub 7} occupy trigonal planar sites instead of octahedral sites. Among quaternary chalcogenides RE{sub 3}MM′Ch{sub 7}, the combination of monovalent (M=Cu) and trivalent (M′=Ga) metals is unusual because it appears to violate the condition of charge balance satisfied by most La{sub 3}CuSiS{sub 7}-type compounds. The possibility of divalent Cu atoms was ruled out by bond valence sum analysis, magnetic measurements, and X-ray photoelectron spectroscopy. The electron deficiency in RE{sub 3}CuGaCh{sub 7} is accommodated through S-based holes at the top of the valence band, as shown by band structure calculations on La{sub 3}CuGaS{sub 7}. An optical band gap of about 2.0 eV was found for La{sub 3}CuGaSe{sub 7}. - Graphical abstract: The chalcogenides RE{sub 3}CuGaCh{sub 7} contain monovalent Cu in trigonal planes and trivalent Ga in tetrahedra; they are electron-deficient representatives of La{sub 3}CuSiS{sub 7}-type compounds, which normally satisfy charge balance. - Highlights: • Quaternary chalcogenides RE{sub 3}CuGaCh{sub 7} (RE=La–Nd; Ch=S, Se) were prepared. • Bond valence sums, magnetism, and XPS data give evidence for monovalent Cu. • Crystal structures reveal high anisotropy of Cu displacement. • Electron deficiency is accommodated by S-based holes in valence band.

  1. 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)

    2013-12-02

    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.

  2. Quantum Energy LLC | Open Energy Information

    Open Energy Info (EERE)

    Place: Niwot, Colorado Zip: 80503 Product: Colorado-based company that is allegedly manufacturing CIGS modules and CPV system through a Taiwanese JV in order to use it in their...

  3. Daiyang Metal Co Ltd | Open Energy Information

    Open Energy Info (EERE)

    Seoul, Seoul, Korea (Republic) Zip: 137-040 Sector: Solar Product: Stainless steel manufacturing and CIGS solar cell maker. Coordinates: 37.557121, 126.977379 Show Map Loading...

  4. Eyelit Inc | Open Energy Information

    Open Energy Info (EERE)

    Mississauga, Ontario, Canada Zip: L4Z 3P8 Product: Provides management software for manufacturing lines. Has at least one contract with an undisclosed CIGS PV developer, in August...

  5. LUXE Co Ltd | Open Energy Information

    Open Energy Info (EERE)

    search Name: LUXE Co Ltd Place: Taiwan Product: Engaged in a venture with US Quantum Energy Ltd to build a 5MW CIGS PV factory in Taiwan. References: LUXE Co Ltd1 This...

  6. MMTSAlt

    Office of Legacy Management (LM)

    ... Option A involves the remediation of the uppermost 2,700 feet of Upper Montezuma Creek to 515 pCig Ra-226 and provides no action in the rest of Upper Montezuma Creek. Option B ...

  7. AxunTek Solar Energy | Open Energy Information

    Open Energy Info (EERE)

    AxunTek Solar Energy Jump to: navigation, search Name: AxunTek Solar Energy Place: Taiwan Sector: Solar Product: Taiwan-based CIGS thin film solar cell producer. References:...

  8. GroupSat Solar | Open Energy Information

    Open Energy Info (EERE)

    search Name: GroupSat Solar Place: Suzhou, Jiangsu Province, China Product: CIGS PV cell and module maker based in Suzhou in China's Jiangsu Province. Coordinates: 31.3092,...

  9. Jenn Feng Co Ltd | Open Energy Information

    Open Energy Info (EERE)

    to: navigation, search Name: Jenn Feng Co Ltd Place: Taoyuan, Taiwan Product: CIGS PV module and power tools maker based in Taoyuan, Taiwan Coordinates: 25.001909, 121.304977...

  10. Document

    Broader source: Energy.gov (indexed) [DOE]

    ... CIG avers that the total cost of the proposed facilities for the Raton Basin Area expansion and increased delivery flexibility is 51,784,900 and the cost of the gas quality ...

  11. Veeco Instruments Inc | Open Energy Information

    Open Energy Info (EERE)

    of production equipment mostly for data storage but also for CIGS thin-film solar and LED MOCVD manufacturing equipment. Coordinates: 44.440496, -72.414991 Show Map Loading...

  12. Individual identification of free hole and electron dynamics...

    Office of Scientific and Technical Information (OSTI)

    as an understanding of this behavior is essential for improving the performance of solar cells composed of CIGS thin films. A characteristic double-peak structure due to the...

  13. Individual identification of free hole and electron dynamics in CuIn{sub 1?x}Ga{sub x}Se{sub 2} thin films by simultaneous monitoring of two optical transitions

    SciTech Connect (OSTI)

    Okano, Makoto; Hagiya, Hideki; Sakurai, Takeaki; Akimoto, Katsuhiro; Shibata, Hajime; Niki, Shigeru; Kanemitsu, Yoshihiko

    2015-05-04

    The photocarrier dynamics of CuIn{sub 1?x}Ga{sub x}Se{sub 2} (CIGS) thin films were studied using white-light transient absorption (TA) measurements, as an understanding of this behavior is essential for improving the performance of solar cells composed of CIGS thin films. A characteristic double-peak structure due to the splitting of the valence bands in the CIGS was observed in the TA spectra under near-band-gap resonant excitation. From a comparison of the TA decay dynamics monitored at these two peaks, it was found that the slow-decay components of the electron and hole relaxation are on the nanosecond timescale. This finding is clear evidence of the long lifetimes of free photocarriers in polycrystalline CIGS thin films.

  14. Processing Materials Devices and Diagnostics for Thin Film Photovoltaics: Fundamental and Manufacturability Issues; Final Report, 5 September 2001 - 31 May 2008

    SciTech Connect (OSTI)

    Birkmire, R. W.; Shafarman, W. N.; Eser, E.; Hegedus, S. S.; McCandless, B. E.; Dobson, K. D.; Bowden, S.

    2009-04-01

    The critical issues addressed in this study on CIGS, CdTe, and a-Si modules will provide the science and engineering basis for developing viable commercial processes and improved module performance.

  15. The Five-Step Development Process Step 1: Identify Project Potential

    Energy Savers [EERE]

    ... 6 to 11% 10% to 11% 12% to 14% Single Crystal * Multi-Crystal * Thin Film * Cadmium Telluride * CIGS Solar Assessment: PV is VERY Shade Sensitive Once preliminary site assessment ...

  16. Timothy J. Coutts - Research Fellow Emeritus | NREL

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

    in photovoltaics since 1970. Experience the development of CdSCuxS, ITOInP, CdSCdTe, InP homojunction solar cells for space application, CIGS and CdTe thin film solar cells. ...

  17. Hole Blocking, Electron Transporting and Window Layer for Optimized...

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

    selenide (CuIn(1-x)GaxSe2 or CIGS) based direct bandgap semiconductors are strong candidates for low cost, high-throughput solar energy harvesting thin film photovoltaic devices. ...

  18. Oregon's Solar Advantage

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

    SolaicxMEMC IngotsWafers Sanyo Solar Oregon IngotsWafers y g g Peak Sun Polysilicon SoloPower Thin Film CIGs Solar Supply Chain Incentives Incentives Compan T pe Company Type PV ...

  19. SoloPower Inc | Open Energy Information

    Open Energy Info (EERE)

    SoloPower Inc Jump to: navigation, search Name: SoloPower Inc Place: San Jose, California Zip: 95138 Product: San Jose-based manufacturer of CIGS PV cells and modules. References:...

  20. Reliability Challenges for Solar Energy (Presentation)

    SciTech Connect (OSTI)

    Kurtz, S.

    2009-04-27

    PV industry can benefit from reliability testing experience of microelectronics industry . Si modules perform well in field; CdTe/CIGS must be sealed to moisture; CPV in product development stage.

  1. Reliability Issues for Photovoltaic Modules (Presentation)

    SciTech Connect (OSTI)

    Kurtz, S.

    2009-10-01

    Si modules good in field; new designs need reliability testing. CdTe & CIGS modules sensitive to moisture; carefully seal. CPV in product development stage; benefits from expertise in other industries.

  2. DayStar Technologies | Open Energy Information

    Open Energy Info (EERE)

    Sector: Solar Product: Manufacturer of low-cost, high performance, CIGS thin film photovoltaic products Number of Employees: 51-200 Year Founded: 1997 Phone Number: 408-582-7100...

  3. NREL preprints for the 23rd IEEE Photovoltaic Specialists Conference

    SciTech Connect (OSTI)

    Fitzgerald, M.

    1993-05-01

    Topics covered include various aspects of solar cell fabrication and performance. Aluminium-gallium arsenides, cadmium telluride, amorphous silicon, and copper-indium-gallium selenides are all characterized in their applicability in solar cells.

  4. Sandia/CINT Research on the Cover of Applied Physics Letters

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

    ... of partially processed device, showing titanium-gold (TiAu) gates on gallium-arsenide... of partially processed device, showing titanium-gold (TiAu) gates on gallium-arsenide...

  5. Effects of phase transformation on the microstructures and magnetostri...

    Office of Scientific and Technical Information (OSTI)

    ... Subject: 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; DOMAIN STRUCTURE; FERROMAGNETIC MATERIALS; FERROMAGNETISM; GALLIUM ALLOYS; IRON BASE ALLOYS; ...

  6. Gamma ray measurements with photoconductive detectors using a...

    Office of Scientific and Technical Information (OSTI)

    AND TECHNOLOGY; ARGON; BREMSSTRAHLUNG; DEUTERIUM; DIAMONDS; GALLIUM ARSENIDES; GAMMA DETECTION; GAMMA RADIATION; HYDROGEN; MEV RANGE; NEON; PHOTOCONDUCTORS; PHOTOMULTIPLIERS;...

  7. Band gap narrowing in zinc oxide-based semiconductor thin films...

    Office of Scientific and Technical Information (OSTI)

    ABSORPTION; ALUMINIUM COMPOUNDS; BORON COMPOUNDS; CHARGE CARRIERS; CONCENTRATION RATIO; DENSITY; DOPED MATERIALS; ELECTRONIC STRUCTURE; ENERGY GAP; GALLIUM COMPOUNDS; INDIUM...

  8. "Title","Creator/Author","Publication Date","OSTI Identifier...

    Office of Scientific and Technical Information (OSTI)

    ABSORPTION; ALUMINIUM COMPOUNDS; BORON COMPOUNDS; CHARGE CARRIERS; CONCENTRATION RATIO; DENSITY; DOPED MATERIALS; ELECTRONIC STRUCTURE; ENERGY GAP; GALLIUM COMPOUNDS; INDIUM...

  9. TITLE AUTHORS SUBJECT SUBJECT RELATED DESCRIPTION PUBLISHER AVAILABILI...

    Office of Scientific and Technical Information (OSTI)

    ABSORPTION ALUMINIUM COMPOUNDS BORON COMPOUNDS CHARGE CARRIERS CONCENTRATION RATIO DENSITY DOPED MATERIALS ELECTRONIC STRUCTURE ENERGY GAP GALLIUM COMPOUNDS INDIUM COMPOUNDS...

  10. Progress in thin film solar photovoltaic technologies

    SciTech Connect (OSTI)

    Ullal, H.S.; Zweibel, K.; Mitchell, R.L. )

    1991-01-01

    This paper focuses on the rapid recent advances made by thin film solar cell technologies, namely, amorphous silicon, copper indium diselenide, and cadmium telluride. It also indicates the several advantages of thin films. Various consumer products and power applications using thin film solar cells are also discussed. The increasing interest among the utilities for PV system applications is also elucidated.

  11. Physics of grain boundaries in polycrystalline photovoltaic semiconductors

    SciTech Connect (OSTI)

    Yan, Yanfa Yin, Wan-Jian; Wu, Yelong; Shi, Tingting; Paudel, Naba R.; Li, Chen; Poplawsky, Jonathan; Wang, Zhiwei; Moseley, John; Guthrey, Harvey; Moutinho, Helio; Al-Jassim, Mowafak M.; Pennycook, Stephen J.

    2015-03-21

    Thin-film solar cells based on polycrystalline Cu(In,Ga)Se{sub 2} (CIGS) and CdTe photovoltaic semiconductors have reached remarkable laboratory efficiencies. It is surprising that these thin-film polycrystalline solar cells can reach such high efficiencies despite containing a high density of grain boundaries (GBs), which would seem likely to be nonradiative recombination centers for photo-generated carriers. In this paper, we review our atomistic theoretical understanding of the physics of grain boundaries in CIGS and CdTe absorbers. We show that intrinsic GBs with dislocation cores exhibit deep gap states in both CIGS and CdTe. However, in each solar cell device, the GBs can be chemically modified to improve their photovoltaic properties. In CIGS cells, GBs are found to be Cu-rich and contain O impurities. Density-functional theory calculations reveal that such chemical changes within GBs can remove most of the unwanted gap states. In CdTe cells, GBs are found to contain a high concentration of Cl atoms. Cl atoms donate electrons, creating n-type GBs between p-type CdTe grains, forming local p-n-p junctions along GBs. This leads to enhanced current collections. Therefore, chemical modification of GBs allows for high efficiency polycrystalline CIGS and CdTe thin-film solar cells.

  12. Effect of Na-doped Mo on Selenization Pathways for CuGa/In Metallic Precursors

    SciTech Connect (OSTI)

    Krishnan, Rangarajan; Tong, Gabriel; Kim, Woo Kyoung; Payzant, E Andrew; Adelhelm, Christoph; Franzke, Enrico; Winkler, Jörg; Anderson, Timothy J

    2013-01-01

    Reaction pathways were followed for selenization of CuGa/In precursor structures using in-situ high temperature X-ray diffraction (HTXRD). Precursor films were deposited on Na-free and Na-doped Mo (3 and 5 at %)/Na-free glass. The precursor film was constituted with CuIn, In, Cu9Ga4, Cu3Ga, Cu16In9 and Mo. HTXRD measurements during temperature ramp selenization showed CIS formation occurs first, followed by CGS formation, and then mixing on the group III sub-lattice to form CIGS. CIGS formation was observed to be complete at ~450 C for samples deposited on 5 at % Na-doped Mo substrates. MoSe2 formation was evidenced after the CIGS synthesis reaction was complete. The Ga distribution in the annealed CIGS was determined by Rietveld refinement. Isothermal reaction studies were conducted for CIGS (112) formation in the temperature range 260-320 C to estimate the rate constants.

  13. Structural tuning of residual conductivity in highly mismatched III-V layers

    DOE Patents [OSTI]

    Han, Jung; Figiel, Jeffrey J.

    2002-01-01

    A new process to control the electrical conductivity of gallium nitride layers grown on a sapphire substrate has been developed. This process is based on initially coating the sapphire substrate with a thin layer of aluminum nitride, then depositing the gallium nitride thereon. This process allows one to controllably produce gallium nitride layers with resistivity varying over as much as 10 orders of magnitude, without requiring the introduction and activation of suitable dopants.

  14. The Influence of Lewis Acid/Base Chemistry on the Removal of...

    Office of Scientific and Technical Information (OSTI)

    These results have an important influence on the potential for simple gallium removal in molten salt systems. Authors: Williams, David F. ; Cul, Guillermo D. del 1 ; Toth, Louis ...

  15. Summer 2011 Intern Project- Jonathan Waltman | Center for Energy...

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

    High efficiency solar cells require multiple junctions optimized for different wavelengths, and indium gallium nitride (InGaN) has the potential to further improve the efficiency ...

  16. Assessment of Latent Heat Reservoirs for Thermal Management of...

    Office of Scientific and Technical Information (OSTI)

    During the early portion of the pulse, heating of the diode and its surrounding material ... Subject: 42 ENGINEERING; CAPACITY; FUSION HEAT; GALLIUM; HEAT FLUX; HEAT TRANSFER; ...

  17. Assessment of Latent Heat Reservoirs for Thermal Management of...

    Office of Scientific and Technical Information (OSTI)

    ... During the early portion of the pulse, heating of the diode and its surrounding material ... Subject: 42 ENGINEERING; CAPACITY; FUSION HEAT; GALLIUM; HEAT FLUX; HEAT TRANSFER; ...

  18. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    ... Filter Results Filter by Subject materials science (28) gallium nitrides (22) solar (photovoltaic), solid state lighting, phonons, materials and chemistry by design, optics, ...

  19. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    ... Las Vegas, Nevada (United States) Yucca Mountain Project... structure (1) cystine (1) death (1) design (1) gallium ... solvothermal rate with CuClsub ...

  20. PTIP Ltd | Open Energy Information

    Open Energy Info (EERE)

    Africa Sector: Solar Product: Thin-film Copper-indium-gallium-sulphur-selenide solar cell technology spinout from the University of Johannesburg. References: PTIP Ltd1 This...

  1. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    ... (1) fibrosis (1) gallium 68 (1) historical (1) intercomparison (1) losses (1) lungs (1) management of radioactive wastes, and non-radioactive wastes from nuclear ...

  2. Bilayer Graphene Gets a Bandgap

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

    nanoelectronics. This is a narrower bandgap than common semiconductors like silicon or gallium arsenide, and it could enable new kinds of optoelectronic devices for generating,...

  3. PROJECT PROFILE: From Modules to Atoms: Increasing Reliability...

    Broader source: Energy.gov (indexed) [DOE]

    The project will study reliability-related defects in major photovoltaic (PV) technologies that include silicon (Si), cadmium telluride (CdTe), and copper indium gallium selenide ...

  4. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    points (1) chemical properties (1) chemistry (1) circulation cell (1) compatibility ... The Influence of Lewis AcidBase Chemistry on the Removal of Gallium by Volatility from ...

  5. Spire Semiconductor formerly Bandwidth Semiconductor LLC | Open...

    Open Energy Info (EERE)

    Zip: 3051 Product: Spire-owned US-based manufacturer of gallium-arsenide (GaAs) cells; offers design and manufacturing capabilities of concentrator cells. References: Spire...

  6. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    structure (1) fermi level (1) fluorescence (1) gallium alloys (1) hole mobility ... a device, has an important function in fluorescence-based organic light-emitting diodes ...

  7. The role of screening of the electron-phonon interaction in relaxation of photoexcited electron-hole plasma in semiconductors

    SciTech Connect (OSTI)

    Kumekov, S. E.

    2008-08-15

    The role of screening of the interaction of the electron-hole plasma with optical phonons is analytically evaluated by the example of gallium arsenide.

  8. High Temperature Aqueous Chemistry

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

    transport and formation of ore deposits with strategic importance such as rare earth elements (REE), beryllium, cobalt, gallium, indium, and telluride deposits, etc., which ...

  9. PRiME 2016 (Honolulu, HI) - JCAP

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

    Cells, and Solar Fuels 7 Sunday, 2 October 2016 Electrochemical Carbon Dioxide Reduction to Hydrocarbons with a Nickel-Gallium Thin Film Catalyst at Low ...

  10. Johanna Solar Technology GmbH JST | Open Energy Information

    Open Energy Info (EERE)

    Havel, Brandenburg, Germany Zip: D-14772 Sector: Solar Product: German manufacturer of copper-indium-gallium-sulphide-selenium (CIGSSe) thin-film solar modules. References: Johanna...

  11. Revealing the Preferred Interlayer Orientations and Stackings...

    Office of Scientific and Technical Information (OSTI)

    Revealing the Preferred Interlayer Orientations and Stackings of Two-Dimensional Bilayer Gallium Selenide Crystals Citation Details In-Document Search Title: Revealing the ...

  12. Intrinsic Semiconductor | Open Energy Information

    Open Energy Info (EERE)

    Intrinsic Semiconductor is a privately held emerging growth company focusing on materials and device technologies based on silicon carbide (SiC) and gallium nitride (GaN)...

  13. Cree Inc | Open Energy Information

    Open Energy Info (EERE)

    North Carolina Zip: 27703 Product: Cree develops and manufactures semiconductor materials and devices based on silicon carbide (SiC), gallium nitride (GaN), silicon (Si) and...

  14. JX Crystals Inc | Open Energy Information

    Open Energy Info (EERE)

    Solar Product: JX Crystals designs and manufactures thermophotovoltaic gallium-antimonide cells for solar applications. Coordinates: 47.530095, -122.033799 Show Map Loading...

  15. Optimized Alumina Coagulants for Water Purification - Energy...

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

    purification. By inserting a single gallium atom in the center of an aluminum oxide cluster, the stability and efficacy of the reagent is greatly improved. This stability also...

  16. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    ... (1) copper silicides (1) critical materials strategy (1) energy conservation, consumption, and utilization materials by design (1) fermions (1) gallium base alloys (1) ...

  17. Smooth and vertical facet formation for AlGaN-based deep-UV laser...

    Office of Scientific and Technical Information (OSTI)

    Sponsoring Org: USDOE Country of Publication: United States Language: English Subject: 36 MATERIALS SCIENCE; 42 ENGINEERING; ALUMINIUM NITRIDES; GALLIUM NITRIDES; ETCHING; LASERS; ...

  18. Progress in thin film solar photovoltaic technologies

    SciTech Connect (OSTI)

    Ullal, H.S.; Zweibel, K.

    1989-12-01

    This paper focuses on the rapid recent advances made by thin film solar cell technologies, namely, amorphous silicon, copper indium diselenide, and cadmium telluride. It also indicates the several advantages of thin films. Various consumer products and power applications using thin film solar cells are also discussed. The increasing interest among the utilities for PV system applications is also elucidated. 29 refs., 8 figs., 3 tabs.

  19. ORISE "AK RlDGE lNSTlT"TE FOR SCIENCE AND EDUCATION

    Office of Legacy Management (LM)

    ... IVC kg km m m3 MDC MeV mremyr mradh NaI NBL NIST ORISE ORNL pCig PMC post-RA PRAR SGS ... the New Brunswick Laboratory (NBL), is located in the town of New Brunswick, New Jersey. ...

  20. CX-100353 Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    Generalizable Mechanistic Understanding of Module-level Light-, Heat- and Humidity-Induced Instabilities in CIGS Photovoltaics Award Number: DE-EE0007141 CX(s) Applied: A9, B3.6, B5.16 Solar Energy Technologies Office Date: 09/02/2015 Location(s): IL Office(s): Golden Field Office

  1. Charge-carrier dynamics in polycrystalline thin-film CuIn{sub 1−x}Ga{sub x}Se{sub 2} photovoltaic devices after pulsed laser excitation: Interface and space-charge region analysis

    SciTech Connect (OSTI)

    Kuciauskas, Darius; Li, Jian V.; Kanevce, Ana; Guthrey, Harvey; Contreras, Miguel; Pankow, Joel; Dippo, Pat; Ramanathan, Kannan

    2015-05-14

    We used time-resolved photoluminescence (TRPL) spectroscopy to analyze time-domain and spectral-domain charge-carrier dynamics in CuIn{sub 1−x}Ga{sub x}Se{sub 2} (CIGS) photovoltaic (PV) devices. This new approach allowed detailed characterization for the CIGS/CdS buffer interface and for the space-charge region. We find that dynamics at the interface is dominated by diffusion, where the diffusion rate is several times greater than the thermionic emission or interface recombination rate. In the space-charge region, the electric field of the pn junction has the largest effect on the carrier dynamics. Based on the minority-carrier (electron) drift-rate dependence on the electric field strength, we estimated drift mobility in compensated CuIn{sub 1−x}Ga{sub x}Se{sub 2} (with x ≈ 0.3) as 22 ± 2 cm{sup 2}(Vs){sup −1}. Analysis developed in this study could be applied to evaluate interface and junction properties of PV and other electronic devices. For CIGS PV devices, TRPL spectroscopy could contribute to understanding effects due to absorber compositional grading, which is one of the focus areas in developing record-efficiency CIGS solar cells.

  2. CX-100073: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    2 Meter Linear High Temperature Evaporation Source for High Speed, Large Area CIGS Module Manufacturing Award Number: DE-EE0006811 CX(s) Applied: A9, B3.6 Solar Energy Technologies Date: 09/17/2014 Location(s): California Office(s): Golden Field Office

  3. CX-010895: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    Development and Industrialization of Indium Gallium Nitride/Gallium Nitride (InGaN/GaN) Light Emitting Diodes LEDs on Patterned Sapphire Substrate (PSS) for Low Cost Emitter Architecture CX(s) Applied: B3.6 Date: 06/27/2013 Location(s): California Offices(s): National Energy Technology Laboratory

  4. Electron-Selective TiO2 Contact for Cu(In,Ga)Se2 Solar Cells

    SciTech Connect (OSTI)

    Hsu, Weitse; Sutter-Fella, Carolin M.; Hettick, Mark; Cheng, Lungteng; Chan, Shengwen; Chen, Yunfeng; Zeng, Yuping; Zheng, Maxwell; Wang, Hsin-Ping; Chiang, Chien-Chih; Javey, Ali

    2015-11-03

    The non-toxic and wide bandgap material TiO2 is explored as an n-type buffer layer on p-type Cu(In,Ga)Se2 (CIGS) absorber layer for thin film solar cells. The amorphous TiO2 thin film deposited by atomic layer deposition process at low temperatures shows conformal coverage on the CIGS absorber layer. Solar cells from non-vacuum deposited CIGS absorbers with TiO2 buffer layer result in a high short-circuit current density of 38.9 mA/cm2 as compared to 36.9 mA/cm2 measured in the reference cell with CdS buffer layer, without compromising open-circuit voltage. The significant photocurrent gain, mainly in the UV part of the spectrum, can be attributed to the low parasitic absorption loss in the ultrathin TiO2 layer (~10 nm) with a larger bandgap of 3.4 eV compared to 2.4 eV of the traditionally used CdS. Overall the solar cell conversion efficiency was improved from 9.5% to 9.9% by substituting the CdS by TiO2 on an active cell area of 10.5 mm2. In conclusion, optimized TiO2/CIGS solar cells show excellent long-term stability. The results imply that TiO2 is a promising buffer layer material for CIGS solar cells, avoiding the toxic CdS buffer layer with added performance advantage.

  5. Electron-Selective TiO2 Contact for Cu(In,Ga)Se2 Solar Cells

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

    Hsu, Weitse; Sutter-Fella, Carolin M.; Hettick, Mark; Cheng, Lungteng; Chan, Shengwen; Chen, Yunfeng; Zeng, Yuping; Zheng, Maxwell; Wang, Hsin-Ping; Chiang, Chien-Chih; et al

    2015-11-03

    The non-toxic and wide bandgap material TiO2 is explored as an n-type buffer layer on p-type Cu(In,Ga)Se2 (CIGS) absorber layer for thin film solar cells. The amorphous TiO2 thin film deposited by atomic layer deposition process at low temperatures shows conformal coverage on the CIGS absorber layer. Solar cells from non-vacuum deposited CIGS absorbers with TiO2 buffer layer result in a high short-circuit current density of 38.9 mA/cm2 as compared to 36.9 mA/cm2 measured in the reference cell with CdS buffer layer, without compromising open-circuit voltage. The significant photocurrent gain, mainly in the UV part of the spectrum, can bemore » attributed to the low parasitic absorption loss in the ultrathin TiO2 layer (~10 nm) with a larger bandgap of 3.4 eV compared to 2.4 eV of the traditionally used CdS. Overall the solar cell conversion efficiency was improved from 9.5% to 9.9% by substituting the CdS by TiO2 on an active cell area of 10.5 mm2. In conclusion, optimized TiO2/CIGS solar cells show excellent long-term stability. The results imply that TiO2 is a promising buffer layer material for CIGS solar cells, avoiding the toxic CdS buffer layer with added performance advantage.« less

  6. Method of making V.sub.3 Ga superconductors

    DOE Patents [OSTI]

    Dew-Hughes, David

    1980-01-01

    An improved method for producing a vanadium-gallium superconductor wire having aluminum as a component thereof is disclosed, said wire being encased in a gallium bearing copper sheath. The superconductors disclosed herein may be fabricated under normal atmospheres and room temperatures by forming a tubular shaped billet having a core composed of an alloy of vanadium and aluminum and an outer sheath composed of an alloy of copper, gallium and aluminum. Thereafter the entire billet is swage reduced to form a wire therefrom and heat treated to form a layer of V.sub.3 Ga in the interior of the wire.

  7. PROJECT PROFILE: 2D Materials for Low Cost Epitaxial Growth of Single Sun

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

    Gallium Arsenide (GaAs) Photovoltaics | Department of Energy 2D Materials for Low Cost Epitaxial Growth of Single Sun Gallium Arsenide (GaAs) Photovoltaics PROJECT PROFILE: 2D Materials for Low Cost Epitaxial Growth of Single Sun Gallium Arsenide (GaAs) Photovoltaics Funding Opportunity: SuNLaMP SunShot Subprogram: Photovoltaics Location: National Renewable Energy Laboratory, Golden, CO SunShot Award Amount: $125,000 Low-cost III-V cells will result in a breakthrough in photovoltaic (PV)

  8. 15.4% CuIn1-XGaXSe2-Based Photovoltaic Cells from Solution-Based Precursor Films

    SciTech Connect (OSTI)

    Bhattacharya, R. N.; Batchelor, W.; Contreras, M. A.; Noufi, R. N.; Hiltner, J. F.; Sites, J. R.

    1999-05-25

    We have fabricated 15.4%- and 12.4%-efficient CuIn1-XGaXSe2 (CIGS)-based photovoltaic devices from solution-based electrodeposition (ED) and electroless-deposition (EL) precursors. As-deposited precursors are Cu-rich CIGS. Additional In, Ga, and Se are added to the ED and EL precursor films by physical vapor deposition (PVD) to adjust the final film composition to CuIn1-XGaXSe2. The ED and EL device parameters are compared with those of a recent world record, an 18.8%-efficient PVD device. The tools used for comparison are current voltage, capacitance voltage, and spectral response characteristics.

  9. Investigations into alterntive substrate, absorber, and buffer layer processing for Cu(In,Ga)Se{sub 2}-based solar cells

    SciTech Connect (OSTI)

    Tuttle, J.R.; Berens, T.A.; Keane, J.

    1996-05-01

    High-performance Cu(In,Ga)Se{sub 2}(CIGS)-based solar cells are presently fabricated within a narrow range of processing options. In this contribution, alternative substrate, absorber, and buffer layer processing is considered. Cell performance varies considerably when alternative substrates are employed. These variations are narrowed with the addition of Na via a Na{sub 2}S compound. Sputtered and electrodeposited CIGS precursors and completed absorbers show promise as alternatives to evaporation. A recrystallization process is required to improve their quality. (In,Ga){sub y}Se buffer layers contribute to cell performance above 10. Further improvements in these alternatives will lead to combined cell performance greater than 10% in the near term.

  10. ULTRA BARRIER TOPSHEET (UBT) FOR FLEXIBLE PHOTOVOLTAICS

    SciTech Connect (OSTI)

    Schubert, Charlene

    2013-01-09

    This slideshow presents work intended to: Scale-up the Generation -1 UBT to 1+meter width full-scale manufacturing; Develop a Generation-2 UBT on the pilot line, targeting improved performance, longer lifetime and lower cost; Transfer Generation-2 UBT from the pilot line to the full-scale manufacturing line in 2014; and Validate service life of Generation-1 UBT for the 25+ year lifetime. 3M has scaled up UBT for production at 1.2 meter width. 3M is conducting extensive lifetime studies including: –Evaluation of customer processing and installation conditions; –Indoor accelerated testing of UBT film and full CIGS modules; –Outdoor testing of UBT film and CIGS modules. Results have been used to improve ultra barrier film performance for flex module applications.

  11. SolarTec AG | Open Energy Information

    Open Energy Info (EERE)

    SolarTec AG Place: Munich, Bavaria, Germany Product: Developing a technology it calls Sol*Con- 700x Fresnel concentrators for use with gallium arsenide or germanium cells, also...

  12. Model of Ni-63 battery with realistic PIN structure (Journal...

    Office of Scientific and Technical Information (OSTI)

    RANGE 01-10; GALLIUM NITRIDES; ILLUMINANCE; MONTE CARLO METHOD; NICKEL 63; SCANNING ELECTRON MICROSCOPY Word Cloud More Like This Full Text Journal Articles DOI: 10.10631.4930870

  13. Summer 2010 Intern Project- Ali Al-Heji | Center for Energy Efficient...

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

    Mentor: Robert M. Farrell Faculty Advisor: James S. Speck Department: Materials Indium gallium nitride (InGaN) solar cells show promise for absorbing high-energy photons with ...

  14. A-15 Superconducting composite wires and a method for making

    DOE Patents [OSTI]

    Suenaga, Masaki; Klamut, Carl J.; Luhman, Thomas S.

    1984-01-01

    A method for fabricating superconducting wires wherein a billet of copper containing filaments of niobium or vanadium is rolled to form a strip which is wrapped about a tin-alloy core to form a composite. The alloy is a tin-copper alloy for niobium filaments and a gallium-copper alloy for vanadium filaments. The composite is then drawn down to a desired wire size and heat treated. During the heat treatment process, the tin in the bronze reacts with the niobium to form the superconductor niobium tin. In the case where vanadium is used, the gallium in the gallium bronze reacts with the vanadium to form the superconductor vanadium gallium. This new process eliminates the costly annealing steps, external tin plating and drilling of bronze ingots required in a number of prior art processes.

  15. Wrapping process for fabrication of A-15 superconducting composite wires

    DOE Patents [OSTI]

    Suenaga, M.; Klamut, C.J.; Luhman, T.S.

    1980-08-15

    A method for fabricating superconducting wires wherein a billet of copper containing filaments of niobium or vanadium is rolled to form a strip which is wrapped about a tin-alloy core to form a composite. The alloy is a tin-copper alloy for niobium filaments and a gallium-copper alloy for vanadium filaments. The composite is then drawn down to a desired wire size and heat treated. During the heat treatment process, the tin in the bronze reacts with the niobium to form the superconductor niobium tin. In the case where vanadium is used, the gallium in the gallium bronze reacts with the vanadium to form the superconductor vanadium gallium. This new process eliminates the costly annealing steps, external tin plating and drilling of bronze ingots required in a number of prior art processes.

  16. Taransys Inc | Open Energy Information

    Open Energy Info (EERE)

    Taransys Inc Jump to: navigation, search Name: Taransys Inc. Place: Ottawa, Ontario, Canada Zip: K2K 2E2 Product: The company specialises in gallium nitride technologies, focussing...

  17. CX-010873: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    Ammonothermal Bulk Gallium Nitride Crystal Growth for Energy Efficient Lightning and Power Electronics CX(s) Applied: B3.6 Date: 05/22/2013 Location(s): California Offices(s): Advanced Research Projects Agency-Energy

  18. Applied Materials Develops an Advanced Epitaxial Growth System to Bring Down LED Costs

    Broader source: Energy.gov [DOE]

    With the help of DOE funding, Applied Materials has developed an advanced epitaxial growth system for gallium nitride (GaN) LED devices that decreases operating costs, increases internal quantum efficiency, and improves binning yields.

  19. Understanding Drooping Light Emitting Diodes CEEM | U.S. DOE...

    Office of Science (SC) Website

    Understanding "droop" may result in cheaper, more efficient LEDs; LEDs are more energy ... indium in Indium Gallium Nitride (InGaN) green LEDs caused a decrease in light intensity. ...

  20. CX-004937: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    Transphorm, Inc. -High Performance Gallium Nitride High Electron Mobility Transistor Modules for Agile Power ElectronicsCX(s) Applied: B3.6Date: 08/05/2010Location(s): CaliforniaOffice(s): Advanced Research Projects Agency - Energy

  1. Direct imaging of enhanced current collection on grain boundaries of Cu(In,Ga)Se{sub 2} solar cells

    SciTech Connect (OSTI)

    Kim, JunHo; Kim, SeongYeon; Jiang, Chun-Sheng; Ramanathan, Kannan; Al-Jassim, Mowafak M.

    2014-02-10

    We report on direct imaging of current collection by performing conductive atomic force microscopy (C-AFM) measurement on a complete Cu(In,Ga)Se{sub 2} solar cell. The localized current was imaged by milling away the top conductive layer of the device by repeated C-AFM scans. The result exhibits enhanced photocurrent collection on grain boundaries (GBs) of CIGS films, consistent with the argument for electric-field-assisted carrier collection on the GBs.

  2. CIS photovoltaic technology. Annual technical report, January 12, 1995--January 11, 1996

    SciTech Connect (OSTI)

    Delahoy, A.E.; Britt, J.S.; Gabor, A.M.

    1996-06-01

    EPV`s overall strategy in developing CIGS photovoltaic technology has been to define and construct a flexible set of large area vacuum deposition equipment and to explore CIGS formation recipes that can be implemented on this equipment. This is the inverse of the conventional approach in which manufacturing techniques are sought that can reproduce a high efficiency laboratory scale process over large areas. A feature of this equipment is the use of proprietary linear sources capable of downwards evaporation. Using recipes generated within this program, CIGS cells with efficiencies up to 13.9% were prepared by EPV under a separate CRADA with NREL. Entirely within this program, an aperture area efficiency of 9.6% was achieved for a laminated submodule of area 135.2 cm{sup 2}. Considerable effort has gone into the preparation and characterization of CIGS prepared on substrates measuring 96.5 cm x 44.5 cm, and good compositional uniformity has been achieved along both the short and long directions of the plate. Despite this, the material has not yet achieved the efficiency levels demonstrated in smaller scale equipment, and recipe development is ongoing. As part of a program to eliminate, if possible, the use of CdS, alternative buffer layers such as InSe, In{sub x}S{sub y}, and ZnSe have been explored, and, to gain insight into junction formation, CdSe. Of these compounds, ZnSe has shown the most promise, and further experiments are being conducted to optimize material and device properties.

  3. Western Gas Sands Project status report, 1 February-29 February 1980

    SciTech Connect (OSTI)

    Not Available

    1980-01-01

    This edition of the WGSP Status Report summarizes the progress during February 1980, of the government-sponsored projects directed toward increasing gas production from low-permeability gas sands of the western United States. The National Laboratories and Energy Technology Centers continued research and experiments toward enhanced gas recovery. The field test and demonstration program continued with various projects, including test data collection by the DOE Well Test Facility at CIG's Miller No. 1 site.

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

    DOE Patents [OSTI]

    Bhattacharya, Raghu N.

    2009-11-03

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

  5. Considerations for Solar Energy Technologies to Make Progress Towards Grid Price Parity

    SciTech Connect (OSTI)

    Woodhouse, Michael; Fu, Ran; Chung, Donald; Horowitz, Kelsey; Remo, Timothy; Feldman, David; Margolis, Robert

    2015-11-07

    In this seminar the component costs for solar photovoltaics module and system prices will be highlighted. As a basis for comparison to other renewable and traditional energy options, the metric of focus will be total lifecycle cost-of-energy (LCOE). Several innovations to traditional photovoltaics technologies (including crystalline silicon, CdTe, and CIGS) and developing technologies (including organics and perovskites) that may close the gaps in LCOE will be discussed.

  6. Computational Materials Science | Materials Science | NREL

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

    Computational Materials Science An image of interconnecting, sphere- and square-shaped particles that appears to be floating in space NREL's computational materials science capabilities span many research fields and interests. Electronic, Optical, and Transport Properties of Photovoltaic Materials Material properties and defect physics of Si, CdTe, III-V, CIGS, CZTS, and hybrid perovskite compounds Reconstruction of, and defect formation on, semiconductor surfaces Electronic and transport

  7. January 2013 Most Viewed Documents for Renewable Energy Sources | OSTI, US

    Office of Scientific and Technical Information (OSTI)

    Dept of Energy Office of Scientific and Technical Information January 2013 Most Viewed Documents for Renewable Energy Sources Photovoltaic Materials Duty, C.; Angelini, J.; Armstrong, B.; Bennett, C.; Evans, B.; Jellison, G. E.; Joshi, P.; List, F.; Paranthaman, P.; Parish, C.; Wereszczak, A. High Efficiency CdTe and CIGS Thin Film Solar Cells: Highlights of the Technologies Challenges (Presentation) Noufi, R. Accelerated UV Test Methods for Encapsulants of Photovoltaic Modules

  8. Progress and issues in polycrystalline thin-film PV technologies

    SciTech Connect (OSTI)

    Zweibel, K.; Ullal, H.S.; Roedern, B. von

    1996-05-01

    Substantial progress has occurred in polycrystalline thin-film photovoltaic technologies in the past 18 months. However, the transition to first-time manufacturing is still under way, and technical problems continue. This paper focuses on the promise and the problems of the copper indium diselenide and cadmium telluride technologies, with an emphasis on continued R&D needs for the near-term transition to manufacturing and for next-generation improvements. In addition, it highlights the joint R&D efforts being performed in the U.S. Department of Energy/National Renewable Energy Laboratory Thin-Film Photovoltaic Partnership Program.

  9. Non-H[sub 2]Se, ultra-thin CIS devices. [CuInSe[sub 2

    SciTech Connect (OSTI)

    Delahoy, A.E.; Britt, J.; Kiss, Z. )

    1993-02-01

    This report describes work done during Phase I of a 3-phase, cost- shared contract. Objective of the subcontract is to demonstrate 12% total-area efficiency copper indium diselenide (CIS) solar cells and 50-W CIS modules average at least 8 W/ft[sup 2] in the third year. At the end of Phase I, EPV delivered to NREL a 1.1 cm[sup 2] CIS cell with an active area efficiency of 10.5%. the corresponding total-area efficiency is 7.9%.

  10. Non-H{sub 2}Se, ultra-thin CIS devices. Annual subcontract report, 10 March 1992--9 November 1992

    SciTech Connect (OSTI)

    Delahoy, A.E.; Britt, J.; Kiss, Z.

    1993-02-01

    This report describes work done during Phase I of a 3-phase, cost- shared contract. Objective of the subcontract is to demonstrate 12% total-area efficiency copper indium diselenide (CIS) solar cells and 50-W CIS modules average at least 8 W/ft{sup 2} in the third year. At the end of Phase I, EPV delivered to NREL a 1.1 cm{sup 2} CIS cell with an active area efficiency of 10.5%. the corresponding total-area efficiency is 7.9%.

  11. Radiation resistance of thin-film solar cells for space photovoltaic power

    SciTech Connect (OSTI)

    Woodyard, J.R.; Landis, G.A.

    1991-01-01

    Copper indium diselenide, cadmium telluride, and amorphous silicon alloy solar cells have achieved noteworthy performance and are currently being studied for space power applications. Cadmium sulfide cells had been the subject of much effort but are no longer considered for space applications. A review is presented of what is known about the radiation degradation of thin film solar cells in space. Experimental cadmium telluride and amorphous silicon alloy cells are reviewed. Damage mechanisms and radiation induced defect generation and passivation in the amorphous silicon alloy cell are discussed in detail due to the greater amount of experimental data available.

  12. Metal organic chemical vapor deposition of 111-v compounds on silicon

    DOE Patents [OSTI]

    Vernon, Stanley M.

    1986-01-01

    Expitaxial composite comprising thin films of a Group III-V compound semiconductor such as gallium arsenide (GaAs) or gallium aluminum arsenide (GaAlAs) on single crystal silicon substrates are disclosed. Also disclosed is a process for manufacturing, by chemical deposition from the vapor phase, epitaxial composites as above described, and to semiconductor devices based on such epitaxial composites. The composites have particular utility for use in making light sensitive solid state solar cells.

  13. Photovoltaics Informatics: Harnessing Energy Science via Data-Driven Approaches

    SciTech Connect (OSTI)

    Suh, C.; Munch, K.; Biagioni, D.; Glynn, S.; Scharf, J.; Contreras, M. A.; Perkins, J. D.; Nelson, B. P.; Jones, W. B.

    2011-01-01

    We discuss our current research focus on photovoltaic (PV) informatics, which is dedicated to functionality enhancement of solar materials through data management and data mining-aided, integrated computational materials engineering (ICME) for rapid screening and identification of multi-scale processing/structure/property/performance relationships. Our current PV informatics research ranges from transparent conducting oxides (TCO) to solar absorber materials. As a test bed, we report on examples of our current data management system for PV research and advanced data mining to improve the performance of solar cells such as CuIn{sub x}Ga{sub 1-x}Se{sub 2} (CIGS) aiming at low-cost and high-rate processes. For the PV data management, we show recent developments of a strategy for data modeling, collection and aggregation methods, and construction of data interfaces, which enable proper archiving and data handling for data mining. For scientific data mining, the value of high-dimensional visualizations and non-linear dimensionality reduction is demonstrated to quantitatively assess how process conditions or properties are interconnected in the context of the development of Al-doped ZnO (AZO) thin films as the TCO layers for CIGS devices. Such relationships between processing and property of TCOs lead to optimal process design toward enhanced performance of CIGS cells/devices.

  14. Spectral properties of a novel laser crystal Y3(In,Ga)2Ga3O12:Cr(3+)--translation

    SciTech Connect (OSTI)

    Li, Y.; Tang, H.; Hang, Y.; Chen, S.

    1991-11-19

    Spectral properties of a novel phonon terminated laser crystal Yttrium(3)(Indium, Gallium)(2)Gallium(3)Oxygen(12): Chromium(3+) grown by the flux method are reported for the first time. The results show that the spectral properties of this novel crystal are compatible with those of Gadolinium(3)(Selenium, Gallium)(3)Gallium(3)Oxygen(12): Chromium(3+) and is a potential ambient temperature tunable laser crystal. Gadolinium(3)(Scandium, Gallium)(2)Gallium(3)Oxygen(12): Chromium(3+) (shortened to GSGG:CR3+) is a type of phonon-terminated laser crystal with excellent capabilities. It has a relatively weak crystal field and relatively strong electron-phonon coupling. At room temperatures a strong terminal phonon emission spectrum with a half width of about 100 nm can be observed. At the same time, experimentally at room temperatures, a wide band continuous tunable laser emission has been observed. Since it has been reported, a great deal of attention has been paid to it. However, since Scandium is rare and expensive its applications are limited.

  15. Preliminary materials assessment for the Satellite Power System (SPS)

    SciTech Connect (OSTI)

    Teeter, R.R.; Jamieson, W.M.

    1980-01-01

    Presently, there are two SPS reference design concepts (one using silicon solar cells; the other using gallium arsenide solar cells). A materials assessment of both systems was performed based on the materials lists set forth in the DOE/NASA SPS Reference System Report: Concept Development and Evaluation Program. This listing identified 22 materials (plus miscellaneous and organics) used in the SPS. Tracing the production processes for these 22 materials, a total demand for over 20 different bulk materials (copper, silicon, sulfuric acid, etc.) and nealy 30 raw materials (copper ore, sand, sulfur ore, etc.) was revealed. Assessment of these SPS material requirements produced a number of potential material supply problems. The more serious problems are those associated with the solar cell materials (gallium, gallium arsenide, sapphire, and solar grade silicon), and the graphite fiber required for the satellite structure and space construction facilities. In general, the gallium arsenide SPS option exhibits more serious problems than the silicon option, possibly because gallium arsenide technology is not as well developed as that for silicon. Results are presented and discussed in detail. (WHK)

  16. Group III-nitride thin films grown using MBE and bismuth

    DOE Patents [OSTI]

    Kisielowski, Christian K.; Rubin, Michael

    2002-01-01

    The present invention comprises growing gallium nitride films in the presence of bismuth using MBE at temperatures of about 1000 K or less. The present invention further comprises the gallium nitride films fabricated using the inventive fabrication method. The inventive films may be doped with magnesium or other dopants. The gallium nitride films were grown on sapphire substrates using a hollow anode Constricted Glow Discharge nitrogen plasma source. When bismuth was used as a surfactant, two-dimensional gallium nitride crystal sizes ranging between 10 .mu.m and 20 .mu.m were observed. This is 20 to 40 times larger than crystal sizes observed when GaN films were grown under similar circumstances but without bismuth. It is thought that the observed increase in crystal size is due bismuth inducing an increased surface diffusion coefficient for gallium. The calculated value of 4.7.times.10.sup.-7 cm.sup.2 /sec. reveals a virtual substrate temperature of 1258 K which is 260 degrees higher than the actual one.

  17. Group III-nitride thin films grown using MBE and bismuth

    DOE Patents [OSTI]

    Kisielowski, Christian K.; Rubin, Michael

    2000-01-01

    The present invention comprises growing gallium nitride films in the presence of bismuth using MBE at temperatures of about 1000 K or less. The present invention further comprises the gallium nitride films fabricated using the inventive fabrication method. The inventive films may be doped with magnesium or other dopants. The gallium nitride films were grown on sapphire substrates using a hollow anode Constricted Glow Discharge nitrogen plasma source. When bismuth was used as a surfactant, two-dimensional gallium nitride crystal sizes ranging between 10 .mu.m and 20 .mu.m were observed. This is 20 to 40 times larger than crystal sizes observed when GaN films were grown under similar circumstances but without bismuth. It is thought that the observed increase in crystal size is due bismuth inducing an increased surface diffusion coefficient for gallium. The calculated value of 4.7.times.10.sup.-7 cm.sup.2 /sec. reveals a virtual substrate temperature of 1258 K which is 260 degrees higher than the actual one.

  18. Determination of Grain Boundary Charging in Cu(In,Ga)Se2 Thin Films: Preprint

    SciTech Connect (OSTI)

    Jiang, C. S.; Contreras, M. A.; Repins, I.; Moutinho, H. R.; Noufi, R.; Al-Jassim, M. M.

    2012-06-01

    Surface potential mapping of Cu(In,Ga)Se2 (CIGS) thin films using scanning Kelvin probe force microscopy (SKPFM) aims to understand the minority-carrier recombination at the grain boundaries (GBs) of this polycrystalline material by examining GB charging, which has resulted in a number of publications. However, the reported results are highly inconsistent. In this paper, we report on the potential mapping by measuring wide-bandgap or high-Ga-content films and by using a complementary atomic force microscopy-based electrical technique of scanning capacitance microscopy (SCM). The results demonstrate consistent, positively charged GBs on our high-quality films with minimal surface defects/charges. The potential image taken on a low-quality film with a 1.2-eV bandgap shows significantly degraded potential contrast on the GBs and degraded potential uniformity on grain surfaces, resulting from the surface defects/charges of the low-quality film. In contrast, the potential image on an improved high-quality film with the same wide bandgap shows significantly improved GB potential contrast and surface potential uniformity, indicating that the effect of surface defects is critical when examining GB charging using surface potential data. In addition, we discuss the effect of the SKPFM setup on the validity of potential measurement, to exclude possible artifacts due to improper SKPFM setups. The SKPFM results were corroborated by using SCM measurements on the films with a CdS buffer layer. The SCM image shows clear GB contrast, indicating different electrical impedance on the GB from the grain surface. Further, we found that the GB contrast disappeared when the CdS window layer was deposited after the CIGS film was exposed extensively to ambient, which was caused by the creation of CIGS surface defects by the ambient exposure.

  19. Improved open-circuit voltage in Cu(In,Ga)Se{sub 2} solar cells with high work function transparent electrodes

    SciTech Connect (OSTI)

    Jäger, Timo Romanyuk, Yaroslav E.; Bissig, Benjamin; Pianezzi, Fabian; Nishiwaki, Shiro; Reinhard, Patrick; Steinhauser, Jérôme; Tiwari, Ayodhya N.; Schwenk, Johannes

    2015-06-14

    Hydrogenated indium oxide (IOH) is implemented as transparent front contact in Cu(In,Ga)Se{sub 2} (CIGS) solar cells, leading to an open circuit voltage V{sub OC} enhanced by ∼20 mV as compared to reference devices with ZnO:Al (AZO) electrodes. This effect is reproducible in a wide range of contact sheet resistances corresponding to various IOH thicknesses. We present the detailed electrical characterization of glass/Mo/CIGS/CdS/intrinsic ZnO (i-ZnO)/transparent conductive oxide (TCO) with different IOH/AZO ratios in the front TCO contact in order to identify possible reasons for the enhanced V{sub OC}. Temperature and illumination intensity-dependent current-voltage measurements indicate that the dominant recombination path does not change when AZO is replaced by IOH, and it is mainly limited to recombination in the space charge region and at the junction interface of the solar cell. The main finding is that the introduction of even a 5 nm-thin IOH layer at the i-ZnO/TCO interface already results in a step-like increase in V{sub OC}. Two possible explanations are proposed and verified by one-dimensional simulations using the SCAPS software. First, a higher work function of IOH as compared to AZO is simulated to yield an V{sub OC} increase by 21 mV. Second, a lower defect density in the i-ZnO layer as a result of the reduced sputter damage during milder sputter-deposition of IOH can also add to a maximum enhanced V{sub OC} of 25 mV. Our results demonstrate that the proper choice of the front TCO contact can reduce the parasitic recombination and boost the efficiency of CIGS cells with improved corrosion stability.

  20. Gallium Pnictides of the Alkaline Earth Metals, Synthesized by Means of the Flux Method: Crystal Structures and Properties of CaGa[subscript 2]Pn[subscript 2], SrGa[subscript 2]As[subscript 2], Ba[subscript 2]Ga[subscript 5]As[subscript 5], and Ba[subscript 4]Ga[subscript 5]Pn[subscript 8] (Pn = P or As)

    SciTech Connect (OSTI)

    He, Hua; Stearrett, Ryan; Nowak, Edmund R.; Bobev, Svilen

    2014-05-28

    The focus of this paper is on the structural characterization of the new Zintl phases CaGa{sub 2}P{sub 2}, CaGa{sub 2}As{sub 2}, SrGa{sub 2}As{sub 2}, and Ba{sub 2}Ga{sub 5}As{sub 5}, and the solid solution (Ba{sub 0.85(1)}Sr{sub 0.15}){sub 2}Ga{sub 5}As{sub 5}, all of which were synthesized from molten metal fluxes.CaGa{sub 2}P{sub 2}, CaGa{sub 2}As{sub 2}, and SrGa{sub 2}As{sub 2} have layered structures with polyanionic layers made of ethane-like Ga{sub 2}P6 and Ga{sub 2}As6 motifs fused through common edges; the polyanionic substructure in Ba{sub 2}Ga{sub 5}As{sub 5} consists of condensed Ga{sub 2}As6 units and GaAs{sub 4} tetrahedra. Ba{sub 4}Ga{sub 5}P{sub 8} and Ba{sub 4}Ga{sub 5}As{sub 8}, another pair of new compounds with channel-like 3D structures, were also synthesized from metal fluxes, and their structures were established from single-crystal X-ray and synchrotron powder diffraction. They are based on GaP{sub 4} and GaAs{sub 4} tetrahedra, with parts of their structures being heavily disordered. The electronic structures computed with the linear muffin-tin orbital (LMTO) method are discussed as well, alongside the thermopower and the electrical conductivity, measured on single crystals of Ba{sub 2}Ga{sub 5}As{sub 5} and the solid solution (Ba{sub 0.85(1)}Sr{sub 0.15}){sub 2} Ga{sub 5}As{sub 5}. They demonstrate that such an approach would be an effective way to fine-tune the transport properties.

  1. Metastable Changes to the Temperature Coefficients of Thin-Film Photovoltaic Modules

    SciTech Connect (OSTI)

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

    2014-07-01

    Transient changes in the performance of thin-film modules with light exposure are a well-known and widely reported phenomenon. These changes are often the result of reversible metastabilities rather than irreversible changes. Here we consider how these metastable changes affect the temperature dependence of photovoltaic performance. We find that in CIGS modules exhibiting a metastable increase in performance with light exposure, the light exposure also induces an increase in the magnitude of the temperature coefficient. It is important to understand such changes when characterizing temperature coefficients and when analyzing the outdoor performance of newly installed modules.

  2. Robust Measurement of Thin-Film Photovoltaic Modules Exhibiting Light-Induced Transients: Preprint

    SciTech Connect (OSTI)

    Deceglie, Michael, G.; Silverman, Timothy J.; Marion, Bill; Kurtz, Sarah R.

    2015-09-09

    Light-induced changes to the current-voltage characteristic of thin-film photovoltaic modules (i.e. light-soaking effects) frustrate the repeatable measurement of their operating power. We describe best practices for mitigating, or stabilizing, light-soaking effects for both CdTe and CIGS modules to enable robust, repeatable, and relevant power measurements. We motivate the practices by detailing how modules react to changes in different stabilization methods. We also describe and demonstrate a method for validating alternative stabilization procedures, such as those relying on forward bias in the dark. Reliable measurements of module power are critical for qualification testing, reliability testing, and power rating.

  3. Damp-Heat Induced Degradation of Transparent Conducting Oxides for Thin Film Solar Cells (Presentation)

    SciTech Connect (OSTI)

    Pern, J.; Noufi, R.; Li, X.; DeHart, C.; To, B.

    2008-05-01

    The objectives are: (1) To achieve a high long-term performance reliability for the thin-film CIGS PV modules with more stable materials, device structure designs, and moisture-resistant encapsulation materials and schemes; (2) to evaluate the DH stability of various transparent conducting oxides (TCOs); (3) to identify the degradation mechanisms and quantify degradation rates; (4) to seek chemical and/or physical mitigation methods, and explore new materials. It's important to note that direct exposure to DH represents an extreme condition that a well-encapsulated thin film PV module may never experience.

  4. Ferromagnetism in undoped One-dimensional GaN Nanowires

    SciTech Connect (OSTI)

    Jeganathan, K. E-mail: jagan@physics.bdu.ac.in; Purushothaman, V.; Debnath, R.; Arumugam, S.

    2014-05-15

    We report an intrinsic ferromagnetism in vertical aligned GaN nanowires (NW) fabricated by molecular beam epitaxy without any external catalyst. The magnetization saturates at ?0.75 emu/gm with the applied field of 3000 Oe for the NWs grown under the low-Gallium flux of 2.4 10{sup ?8} mbar. Despite a drop in saturation magnetization, narrow hysteresis loop remains intact regardless of Gallium flux. Magnetization in vertical standing GaN NWs is consistent with the spectral analysis of low-temperature photoluminescence pertaining to Ga-vacancies associated structural defects at the nanoscale.

  5. SOLDERING OF ALUMINUM BASE METALS

    DOE Patents [OSTI]

    Erickson, G.F.

    1958-02-25

    This patent deals with the soldering of aluminum to metals of different types, such as copper, brass, and iron. This is accomplished by heating the aluminum metal to be soldered to slightly above 30 deg C, rubbing a small amount of metallic gallium into the part of the surface to be soldered, whereby an aluminum--gallium alloy forms on the surface, and then heating the aluminum piece to the melting point of lead--tin soft solder, applying lead--tin soft solder to this alloyed surface, and combining the aluminum with the other metal to which it is to be soldered.

  6. Npn double heterostructure bipolar transistor with ingaasn base region

    DOE Patents [OSTI]

    Chang, Ping-Chih; Baca, Albert G.; Li, Nein-Yi; Hou, Hong Q.; Ashby, Carol I. H.

    2004-07-20

    An NPN double heterostructure bipolar transistor (DHBT) is disclosed with a base region comprising a layer of p-type-doped indium gallium arsenide nitride (InGaAsN) sandwiched between n-type-doped collector and emitter regions. The use of InGaAsN for the base region lowers the transistor turn-on voltage, V.sub.on, thereby reducing power dissipation within the device. The NPN transistor, which has applications for forming low-power electronic circuitry, is formed on a gallium arsenide (GaAs) substrate and can be fabricated at commercial GaAs foundries. Methods for fabricating the NPN transistor are also disclosed.

  7. Recent Progress toward Robust Photocathodes

    SciTech Connect (OSTI)

    Mulhollan, G. A.; Bierman, J. C. [Saxet Surface Science, Austin, TX 78744 (United States)

    2009-08-04

    RF photoinjectors for next generation spin-polarized electron accelerators require photo-cathodes capable of surviving RF gun operation. Free electron laser photoinjectors can benefit from more robust visible light excited photoemitters. A negative electron affinity gallium arsenide activation recipe has been found that diminishes its background gas susceptibility without any loss of near bandgap photoyield. The highest degree of immunity to carbon dioxide exposure was achieved with a combination of cesium and lithium. Activated amorphous silicon photocathodes evince advantageous properties for high current photoinjectors including low cost, substrate flexibility, visible light excitation and greatly reduced gas reactivity compared to gallium arsenide.

  8. Simple intrinsic defects in GaAs : numerical supplement.

    SciTech Connect (OSTI)

    Schultz, Peter Andrew

    2012-04-01

    This Report presents numerical tables summarizing properties of intrinsic defects in gallium arsenide, GaAs, as computed by density functional theory. This Report serves as a numerical supplement to the results published in: P.A. Schultz and O.A. von Lilienfeld, 'Simple intrinsic defects in GaAs', Modelling Simul. Mater. Sci Eng., Vol. 17, 084007 (2009), and intended for use as reference tables for a defect physics package in device models. The numerical results for density functional theory calculations of properties of simple intrinsic defects in gallium arsenide are presented.

  9. Low dimensional GaAs/air vertical microcavity lasers

    SciTech Connect (OSTI)

    Gessler, J.; Steinl, T.; Fischer, J.; Hfling, S.; Schneider, C.; Kamp, M.; Mika, A.; S?k, G.; Misiewicz, J.

    2014-02-24

    We report on the fabrication of gallium arsenide (GaAs)/air distributed Bragg reflector microresonators with indium gallium arsenide quantum wells. The structures are studied via momentum resolved photoluminescence spectroscopy which allows us to investigate a pronounced optical mode quantization of the photonic dispersion. We can extract a length parameter from these quantized states whose upper limit can be connected to the lateral physical extension of the microcavity via analytical calculations. Laser emission from our microcavity under optical pumping is observed in power dependent investigations.

  10. All-metallic electrically gated 2H-TaSe{sub 2} thin-film switches and logic circuits

    SciTech Connect (OSTI)

    Renteria, J.; Jiang, C.; Yan, Z.; Samnakay, R.; Goli, P.; Pope, T. R.; Salguero, T. T.; Wickramaratne, D.; Lake, R. K.; Khitun, A. G.; Balandin, A. A.

    2014-01-21

    We report the fabrication and performance of all-metallic three-terminal devices with tantalum diselenide thin-film conducting channels. For this proof-of-concept demonstration, the layers of 2H-TaSe{sub 2} were exfoliated mechanically from single crystals grown by the chemical vapor transport method. Devices with nanometer-scale thicknesses exhibit strongly non-linear current-voltage characteristics, unusual optical response, and electrical gating at room temperature. We have found that the drain-source current in thin-film 2H-TaSe{sub 2}Ti/Au devices reproducibly shows an abrupt transition from a highly resistive to a conductive state, with the threshold tunable via the gate voltage. Such current-voltage characteristics can be used, in principle, for implementing radiation-hard all-metallic logic circuits. These results may open new application space for thin films of van der Waals materials.

  11. Siemens solar CIS photovoltaic module and system performance at the National Renewable Energy Laboratory

    SciTech Connect (OSTI)

    Strand, T.; Kroposki, B.; Hansen, R.; Willett, D.

    1996-05-01

    This paper evaluates the individual module and array performance of Siemens Solar Industries copper indium diselenide (CIS) polycrystalline thin-film technology. This is accomplished by studying module and array performance over time. Preliminary temperature coefficients for maximum power, maximum-power voltage, maximum-power current, open-circuit voltage, short-circuit current, and fill factor are determined at both the module and array level. These coefficients are used to correct module/array performance to 25{degrees}C to evaluate stability. The authors show that CIS exhibits a strong inverse correlation between array power and back-of-module temperature. This is due mainly to the narrow bandgap of the CIS material, which results in a strong inverse correlation between voltage and temperature. They also show that the temperature-corrected module and array performance has been relatively stable over the evaluation interval ({approx}2 years).

  12. Transuranic measurements for in situ vitrification

    SciTech Connect (OSTI)

    Subrahmanyam, V.B.

    1987-05-01

    Radioactivity in soil below the crib 216-Z-12 in 200 West Area of Hanford was characterized. Four collinear wells in East-West direction were drilled for this investigation. Soil samples from different locations of three cores from 18 to 28 feet depths were analyzed. Actinides, /sup 241/Am, /sup 239/Pu, and /sup 237/U and fission products /sup 154/Eu and /sup 137/Cs were detected in a well-defined narrow layer (<2 feet) at the crib bottom. Spatial distribution of activity and moisture content were also investigated. The major component of observed radioactivity was due to transuranium isotopes, with three to four orders of magnitude lower activity from the other nuclides. The maximum detected specific activity of 3000 +- 300 nCig may represent the retention capacity of the soil. The highest activity position varied in depth from 20.5 to 22.6 feet with higher activity occurring at deeper locations away in both directions from the effluent discharge pipe. The full width at half maximum (FWHM) activity was 0.2 foot in the western well and increased gradually to 1.2 feet in the eastern well. The activity layer in the investigated vertical plane could be represented by average values, for specific activity and FWHM, respectively, of 3000 nCig and 0.82 foot. 14 refs., 9 figs.

  13. Density Profiles in Sputtered Molybdenum Thin Films and Their Effects on Sodium Diffusion in Cu(InxGa1-x)Se2 Photovoltaics

    SciTech Connect (OSTI)

    Li, J.; Glynn, S.; Mansfield, L.; Young, M.; Yan, Y.; Contreras, M.; Noufi, R.; Terry Jr., F. L.; Levi, D.

    2011-01-01

    Molybdenum (Mo) thin films were sputtered onto soda lime glass (SLG) substrates. The main variable in the deposition parameters, the argon (Ar) pressure p{sub Ar}, was varied in the range of 6-20 mTorr. Ex situ spectroscopic ellipsometry (SE) was performed to find out that the dielectric functions {var_epsilon} of the Mo films were strongly dependent on p{sub Ar}, indicating a consistent and significant decrease in the Mo film density {rho}{sub Mo} with increasing p{sub Ar}. This trend was confirmed by high-angle-annular-dark-field scanning transmission electron microscopy. {var_epsilon} of Mo was then found to be correlated with secondary ion mass spectroscopy profiles of Sodium (Na) in the Cu(In{sub x}Ga{sub 1-x})Se{sub 2} (CIGS) layer grown on top of Mo/SLG. Therefore, in situ optical diagnostics can be applied for process monitoring and optimization in the deposition of Mo for CIGS solar cells. Such capability is demonstrated with simulated optical transmission and reflectance of variously polarized incident light, using {var_epsilon} deduced from SE.

  14. Properties of Wide-Gap Chalcopyrite Semiconductors for Photovoltaic Applications: Final Report, 8 July 1998 -- 17 October 2001

    SciTech Connect (OSTI)

    Rockett, A.

    2003-07-01

    The objectives of this project were to obtain a fundamental understanding of wide-gap chalcopyrite semiconductors and photovoltaic devices. Information to be gathered included significant new fundamental materials data necessary for accurate modeling of single- and tandem-junction devices, basic materials science of wider-gap chalcopyrite semiconductors to be used in next-generation devices, and practical information on the operation of devices incorporating these materials. Deposition used a hybrid sputtering and evaporation method shown previously to produce high-quality epitaxial layers of Cu(In,Ga)Se2 (CIGS). Materials analysis was also provided to assist members of the National CIS Team, of which, through this contract, we were a member. Solar cells produced from resulting single-crystal epitaxial layers in collaboration with various members of the CIS Team were used to determine the factors limiting performance of the devices based on analysis of the results. Because epitaxial growth allows us to determine the surface orientation of our films specifically by choice of the substrate surface on which the film is grown, a major focus of the project concerned the nature of (110)-oriented CIGS films and the performance of solar cells produced from these films. We begin this summary with a description of the results for growth on (110) GaAs, which formed a basis for much of the work ultimately conducted under the program.

  15. Inkjet Printed Metallizations for Cu(In1-xGax)Se2 Photovoltaic Cells

    SciTech Connect (OSTI)

    Hersh, P. A.; Curtis, C. J.; van Hest, M. F. A. M.; Kreuder, J. J.; Pasquarelli, R.; Miednaer, A.; Ginley, D. S.

    2011-12-01

    This study reports the inkjet printing of Ag front contacts on Aluminum doped Zinc Oxide (AZO)/intrinsic Zinc Oxide (i-ZnO)/CdS/Cu(In{sub 1-x}Ga{sub x})Se{sub 2} (CIGS)/Mo thin film photovoltaic cells. The printed Ag contacts are being developed to replace the currently employed evaporated Ni/Al bi-layer contacts. Inkjet deposition conditions were optimized to reduce line resistivity and reduce contact resistance to the Al:ZnO layer. Ag lines printed at a substrate temperature of 200 C showed a line resistivity of 2.06 {mu}{Omega} {center_dot} cm and a contact resistance to Al:ZnO of 8.2 {+-} 0.2 m{Omega} {center_dot} cm{sup 2} compared to 6.93 {+-} 0.3 m{Omega} {center_dot} cm{sup 2} for thermally evaporated contacts. These deposition conditions were used to deposit front contacts onto high quality CIGS thin film photovoltaic cells. The heating required to print the Ag contacts caused the performance to degrade compared to similar devices with evaporated Ni/Al contacts that were not heated. Devices with inkjet printed contacts showed 11.4% conversion efficiency compared to 14.8% with evaporated contacts. Strategies to minimize heating, which is detrimental for efficiency, during inkjet printing are proposed.

  16. Influence of Damp Heat on the Electrical, Optical, and Morphological Properties of Encapsulated CuInGaSe2 Devices: Preprint

    SciTech Connect (OSTI)

    Sundaramoorthy, R.; Pern, F. J.; Teeter, G.; Li, J. V.; Young, M.; Kuciauskas, D.; Call, N.; Yan, F.; To, B.; Johnston, S.; Noufi, R.; Gessert, T. A.

    2011-08-01

    CuInGaSe2 (CIGS) devices, encapsulated with different backsheets having different water vapor transmission rates (WVTR), were exposed to damp heat (DH) at 85C and 85% relative humidity (RH) and characterized periodically to understand junction degradation induced by moisture ingress. Performance degradation of the devices was primarily driven by an increase in series resistance within first 50 h of exposure, resulting in a decrease in fill factor and, accompanied loss in carrier concentration and widening of depletion width. Surface analysis of the devices after 700-h DH exposure showed the formation of Zn(OH)2 from hydrolysis of the Al-doped ZnO (AZO) window layer by the moisture, which was detrimental to the collection of minority carriers. Minority carrier lifetimes observed for the CIGS devices using time resolved photoluminescence (TRPL) remained relatively long after DH exposure. By etching the DH-exposed devices and re-fabricating with new component layers, the performance of reworked devices improved significantly, further indicating that DH-induced degradation of the AZO layer and/or the CdS buffer was the primary performance-degrading factor.

  17. Thickness Effect of Al-Doped ZnO Window Layer on Damp Heat Stability of CuInGaSe2 Solar Cells: Preprint

    SciTech Connect (OSTI)

    Pern, F. J.; Mansfield, L.; DeHart, C.; Glick, S. H.; Yan, F.; Noufi, R.

    2011-07-01

    We investigated the damp heat (DH) stability of CuInGaSe2 (CIGS) solar cells as a function of thickness of the Al-doped ZnO (AZO) window layer from the 'standard' 0.12 μm to a modest 0.50 μm over an underlying 0.10-μm intrinsic ZnO buffer layer. The CIGS cells were prepared with external electrical contact using fine Au wire to the tiny 'standard' Ni/Al (0.05 μm/3 μm) metal grid contact pads. Bare cell coupons and sample sets encapsulated in a specially designed, Al-frame test structure with an opening for moisture ingress control using a TPT backsheet were exposed to DH at 85oC and 85% relative humidity, and characterized by current-voltage (I-V), quantum efficiency (QE), and (electrochemical) impedance spectroscopy (ECIS). The results show that bare cells exhibited rapid degradation within 50-100 h, accompanied by film wrinkling and delamination and corrosion of Mo and AlNi grid, regardless of AZO thickness. In contrast, the encapsulated cells did not show film wrinkling, delamination, and Mo corrosion after 168 h DH exposure; but the trend of efficiency degradation rate showed a weak correlation to the AZO thickness.

  18. Influence of Damp Heat on the Electrical, Optical, and Morphological Properties of Encapsulated CuInGaSe2 Devices

    SciTech Connect (OSTI)

    Sundaramoorthy, R.; Pern, F. J.; Teeter, G.; Li, Jian V.; Young, M.; Kuciauskas, D.; Call, N.; Yan, F.; To, B.; Johnston, S.; Noufi, R.; Gessert, T. A.

    2011-01-01

    CuInGaSe{sub 2} (CIGS) devices, encapsulated with different backsheets having different water vapor transmission rates (WVTR), were exposed to damp heat (DH) at 85 C and 85% relative humidity (RH) and characterized periodically to understand junction degradation induced by moisture ingress. Performance degradation of the devices was primarily driven by an increase in series resistance within first 50 h of exposure, resulting in a decrease in fill factor and, accompanied loss in carrier concentration and widening of depletion width. Surface analysis of the devices after 700-h DH exposure showed the formation of Zn(OH){sub 2} from hydrolysis of the Al-doped ZnO (AZO) window layer by the moisture, which was detrimental to the collection of minority carriers. Minority carrier lifetimes observed for the CIGS devices using time resolved photoluminescence (TRPL) remained relatively long after DH exposure. By etching the DH-exposed devices and re-fabricating with new component layers, the performance of reworked devices improved significantly, further indicating that DH-induced degradation of the AZO layer and/or the CdS buffer was the primary performance-degrading factor.

  19. Thickness Effect of Al-Doped ZnO Window Layer on Damp-Heat Stability of CuInGaSe2 Solar Cells

    SciTech Connect (OSTI)

    Pern, F. J.; Mansfield, L.; DeHart, C.; Glick, S. H.; Yan, F.; Noufi, R.

    2011-01-01

    We investigated the damp heat (DH) stability of CuInGaSe{sub 2} (CIGS) solar cells as a function of thickness of the Al-doped ZnO (AZO) window layer from the 'standard' 0.12 {micro}m to a modest 0.50 {micro}m over an underlying 0.10-{micro}m intrinsic ZnO buffer layer. The CIGS cells were prepared with external electrical contact using fine Au wire to the tiny 'standard' Ni/Al (0.05 {micro}m/3 {micro}m) metal grid contact pads. Bare cell coupons and sample sets encapsulated in a specially designed, Al-frame test structure with an opening for moisture ingress control using a TPT backsheet were exposed to DH at 85 C and 85% relative humidity, and characterized by current-voltage (I-V), quantum efficiency (QE), and (electrochemical) impedance spectroscopy (ECIS). The results show that bare cells exhibited rapid degradation within 50-100 h, accompanied by film wrinkling and delamination and corrosion of Mo and AlNi grid, regardless of AZO thickness. In contrast, the encapsulated cells did not show film wrinkling, delamination, and Mo corrosion after 168 h DH exposure; but the trend of efficiency degradation rate showed a weak correlation to the AZO thickness.

  20. Activation of small alkanes in Ga-exchanged zeolites: A quantum chemical study of ethane dehydrogenation

    SciTech Connect (OSTI)

    Frash, M.V.; Santen, R.A. van

    2000-03-23

    Quantum chemical calculations on the mechanism of ethane dehydrogenation catalyzed by Ga-exchanged zeolites have been undertaken. Two forms of gallium, adsorbed dihydride gallium ion GaH{sub 2}+Z{sup {minus}} and adsorbed gallyl ion [Ga=O]{sup +}Z{sup {minus}}, were considered. It was found that GaH{sub 2}{sup +}Z{sup {minus}} is the likely active catalyst. On the contrary, [Ga=O]{sup +}Z{sup {minus}} cannot be a working catalyst in nonoxidative conditions, because regeneration of this form is very difficult. Activation of ethane by GaH{sub 2}{sup +}Z{sup {minus}} occurs via an alkyl mechanism and the gallium atom acts as an acceptor of the ethyl group. The carbenium activation of ethane, with gallium abstracting a hydride ion, is much (ca. 51 kcal/mol) more difficult. The catalytic cycle for the alkyl activation consists of three elementary steps: (1) rupture of the ethane C-H bond; (2) formation of dihydrogen from the Bronsted proton and hydrogen bound to Ga; and (3) formation of ethene from the ethyl group bound to Ga. The best estimates (MP2/6--311++G(2df,p)//B3LYP/6--31G*) for the activation energies of these three steps are 36.9, ca. 0, and 57.9 kcal/mol, respectively.

  1. Cantilever Epitaxy Process Wins R&D 100 Award

    Broader source: Energy.gov [DOE]

    Sandia National Laboratories received an R&D 100 Award from R&D Magazine for development of a new process for growing gallium nitride on an etched sapphire substrate. The process, called cantilever epitaxy, promises to make brighter and more efficient green, blue, and white LEDs.

  2. CX-010974: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    Advanced Low-Cost Silicon Carbide (SiC) and Gallium Nitride (GaN) Wide Bandgap Inverters for Under-the-Hood Electric Vehicle Traction... CX(s) Applied: B3.6 Date: 09/16/2013 Location(s): Arkansas Offices(s): National Energy Technology Laboratory

  3. CX-010973: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    Advanced Low-Cost Silicon Carbide (SiC) and Gallium Nitride (GaN) Wide Bandgap Inverters for Under-the-Hood Electric Vehicle Traction... CX(s) Applied: B3.6 Date: 09/16/2013 Location(s): Arkansas Offices(s): National Energy Technology Laboratory

  4. CX-000845: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    25A2445 - Ammonothermal Bulk Gallium Nitride (GaN) Crystal Growth for Energy Efficient LightingCX(s) Applied: B3.6Date: 01/15/2010Location(s): New YorkOffice(s): Advanced Research Projects Agency - Energy

  5. CX-001137: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    Advanced Epi Tools for Gallium Nitride LED (Light Emitting Diode) DevicesCX(s) Applied: B3.6Date: 03/05/2010Location(s): Santa Clara, CaliforniaOffice(s): Energy Efficiency and Renewable Energy, National Energy Technology Laboratory

  6. Method of forming particulate materials for thin-film solar cells

    DOE Patents [OSTI]

    Eberspacher, Chris; Pauls, Karen Lea

    2004-11-23

    A method for preparing particulate materials useful in fabricating thin-film solar cells is disclosed. Particulate materials is prepared by the method include for example materials comprising copper and indium and/or gallium in the form of single-phase, mixed-metal oxide particulates; multi-phase, mixed-metal particulates comprising a metal oxide; and multinary metal particulates.

  7. Investigation on growth and laser properties of GGG:(Nd,Cr) single crystals

    SciTech Connect (OSTI)

    Zhang; Lin; Liu; Liu; Zhu

    1986-04-04

    Investigation on the growth and laser properties of gadolinium gallium garnet crystal doped with neodymium and chromium is reported. As the segregation coefficient of Nd in GGG is less than 1 and that of Cr is greater than 1, a modified Czochralski method for growth is adopted in order to keep the dopants being uniform in the grown crystal.

  8. Aluminum battery alloys

    DOE Patents [OSTI]

    Thompson, D.S.; Scott, D.H.

    1984-09-28

    Aluminum alloys suitable for use as anode structures in electrochemical cells are disclosed. These alloys include iron levels higher than previously felt possible, due to the presence of controlled amounts of manganese, with possible additions of magnesium and controlled amounts of gallium.

  9. Aluminum battery alloys

    DOE Patents [OSTI]

    Thompson, David S.; Scott, Darwin H.

    1985-01-01

    Aluminum alloys suitable for use as anode structures in electrochemical cs are disclosed. These alloys include iron levels higher than previously felt possible, due to the presence of controlled amounts of manganese, with possible additions of magnesium and controlled amounts of gallium.

  10. Research Cell Efficiency Records

    Broader source: Energy.gov [DOE]

    The National Renewable Energy Laboratory maintains a plot of compiled values of highest confirmed conversion efficiencies for research cells, from 1976 to the present, for a range of photovoltaic technologies. This chart highlights cell efficiency results within different families of semiconductors: (1) multijunction cells, (2) single-junction gallium arsenide cells, (3) crystalline silicon cells, (4) thinfilm technologies, and (5) emerging photovoltaics.

  11. CX-011468: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    Advanced Low-Cost Silicon-Carbide (SiC) and Gallium-Nitride (GaN) Wide Bandgap Inverters for Under-the-Hood Electric Vehicle Traction... CX(s) Applied: B3.6 Date: 10/29/2013 Location(s): Michigan Offices(s): National Energy Technology Laboratory

  12. CX-009000: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    "High Quality, Low Cost Bulk Gallium Nitride (GaN) Substrates Grown by the Electrochemical Solution Growth Method CX(s) Applied: A9, B3.6 Date: 08/20/2012 Location(s): Missouri Offices(s): Golden Field Office"

  13. Method for non-invasive detection of ocular melanoma

    DOE Patents [OSTI]

    Lambrecht, R.M.; Packer, S.

    1984-10-30

    An apparatus and method is disclosed for diagnosing ocular cancer that is both non-invasive and accurate. The apparatus comprises two radiation detectors positioned before each of the patient's eyes which will measure the radiation level produced in each eye after the administration of a tumor-localizing radiopharmaceutical such as gallium-67. 2 figs.

  14. Differential radioactivity monitor for non-invasive detection of ocular melanoma

    DOE Patents [OSTI]

    Lambrecht, R.M.; Packer, S.

    1982-09-23

    There is described an apparatus and method for diagnosing ocular cancer that is both non-invasive and accurate which comprises two radiation detectors positioned before each of the patient's eyes which will measure the radiation level produced in each eye after the administration of a tumor-localizing radiopharmaceutical such as gallium-67.

  15. CX-006555: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    Gallium Nitride Electronics for Grid ApplicationsCX(s) Applied: A1, A2, A9, A11, B3.6Date: 08/17/2011Location(s): Lexington, MassachusettsOffice(s): Electricity Delivery and Energy Reliability, National Energy Technology Laboratory

  16. Liquid precursor inks for deposition of In--Se, Ga--Se and In--Ga--Se

    SciTech Connect (OSTI)

    Curtis, Calvin J.; Hersh, Peter A.; Miedaner, Alexander; Habas, Susan; van Hest, Maikel; Ginley, David S.

    2015-08-11

    An ink includes a solution of selenium in ethylene diamine solvent and a solution of at least one metal salt selected from the group consisting of an indium salt or a gallium salt in at least one solvent including an organic amide. The organic amide can include dimethylformamide. The organic amide can include N-methylpyrrolidone.

  17. CX-006556: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    Gallium Nitride Electronics for Grid ApplicationsCX(s) Applied: A1, A2, A9, A11, B3.6Date: 08/17/2011Location(s): Cambridge, MassachusettsOffice(s): Electricity Delivery and Energy Reliability, National Energy Technology Laboratory

  18. Method for non-invasive detection of ocular melanoma

    DOE Patents [OSTI]

    Lambrecht, Richard M.; Packer, Samuel

    1984-01-01

    There is described an apparatus and method for diagnosing ocular cancer that is both non-invasive and accurate which comprises two radiation detectors positioned before each of the patient's eyes which will measure the radiation level produced in each eye after the administration of a tumor-localizing radiopharmaceutical such as gallium-67.

  19. Synthesis and use of (perfluoroaryl) fluoro-aluminate anion

    DOE Patents [OSTI]

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

    2001-01-01

    A trityl perfluorophenyl alumninate such as tris(2,2',2"-nonafluorobiphenyl)-fluoroaluminate (PBA.sup..crclbar.) and its role as a cocatalyst in metallocene-mediated olefin polymerization is disclosed. Gallium and indium analogs are also disclosed, as are analogs with different anyl groups or different numbers of flourine atoms thereon.

  20. Time-resolved photoluminescence of ytterbium in indium phosphide. Master's thesis

    SciTech Connect (OSTI)

    Bumgarner, T.F.

    1988-12-01

    Time-resolved photoluminescence of ytterbium (Yb) implanted in indium phosphide (Inp) was the primary emphasis of this research. The decay lifetimes of the 1002-nm Yb emission were investigated as a function of temperature. Initial attempts were made to investigate as a function of temperature. Initial attempts were made to investigate aluminum gallium arsenide (AlGaAs) implanted with ytterbium.

  1. Sinus histiocytosis with massive lymphadenopathy

    SciTech Connect (OSTI)

    Pastakia, B.; Weiss, S.H.

    1987-11-01

    Gallium uptake corresponding to the extent of the disease in a patient with histologically proven sinus histiocytosis with massive lymphadenopathy (SHML) is reported. Computerized tomography confirmed the presence of bilateral retrobulbar masses, involvement of both lateral recti, erosion of the bony orbital floor with encroachment of tumor into the right maxillary antrum, and retropharyngeal involvement.

  2. Manufacturable CuIn(Ga)Se{sub 2}-based solar cells via development of co-sputtered CuInSe{sub 2} absorber layers

    SciTech Connect (OSTI)

    Dr. Ingrid Eisgruber

    1999-03-20

    Yield and reproducibility remain issues in CuIn(Ga)Se{sub 2} (CIGS) photovoltaic module fabrication. While small-area cells (<1 cm{sup 2}) over 18% efficient have been reported, the best large-area manufactured devices (>1 ft{sup 2}) are 11% efficient with about 60% yield. If improvements in large-area manufacturing can accomplish 15% efficiency and 90% yield, the result is a doubling in throughput leading to a reduction in cost per watt of over 50%. The challenge now facing the photovoltaics industry is to bring the efficiencies of small-area cells and large-area industrial modules closer together and to raise manufacturing yields.

  3. Improving Translation Models for Predicting the Energy Yield of Photovoltaic Power Systems. Cooperative Research and Development Final Report, CRADA Number CRD-13-526

    SciTech Connect (OSTI)

    Emery, Keith

    2015-08-04

    The project under this CRADA will analyze field data of various flat-plate and concentrator module technologies and cell measurements at the laboratory level. The field data will consist of current versus voltage data collected over many years on a latitude tilt test bed for Si, CdTe, amorphous silicon, and CIGS technologies. The concentrator data will be for mirror- and lens-based module designs using multijunction cells. The laboratory data will come from new measurements of cell performance with systematic variation of irradiance, temperature and spectral composition. These measurements will be labor-intensive and the aim will be to cover the widest possible parameter space for as many different PV samples as possible. The data analysis will require software tools to be developed. These tools will be customized for use with the specific NREL datasets and will be unsuitable for commercial release. The tools will be used to evaluate different translation equations against NREL outdoor datasets.

  4. Temperature-Dependent Light-Stabilized States in Thin-Film PV Modules

    SciTech Connect (OSTI)

    Deceglie, Michael G.; Silverman, Timothy J.; Marion, Bill; Kurtz, Sarah R.

    2015-06-14

    Thin-film photovoltaic modules are known to exhibit light-induced transient behavior which interferes with accurate and repeatable measurements of power. Typically power measurements are made after a light exposure in order to target a 'light state' of the module that is representative of outdoor performance. Here we show that the concept of a unique light state is poorly defined for both CIGS and CdTe modules. Instead we find that their metastable state after a light exposure can depend on the temperature of the module during the exposure. We observe changes in power as large as 5.8% for a 20 degrees C difference in light exposure temperature. These results lead us to conclude that for applications in which reproducibility and repeatability are critical, module temperature should be tightly controlled during light exposure.

  5. Temperature-Dependent Light-Stabilized States in Thin-Film PV Modules: Preprint

    SciTech Connect (OSTI)

    Deceglie, Michael G.; Silverman, Timothy J.; Marion, Bill; Kurtz, Sarah R.

    2015-09-17

    Thin-film photovoltaic modules are known to exhibit light-induced transient behavior which interferes with accurate and repeatable measurements of power. Typically power measurements are made after a light exposure in order to target a 'light state' of the module that is representative of outdoor performance. Here we show that the concept of a unique light state is poorly defined for both CIGS and CdTe modules. Instead we find that their metastable state after a light exposure can depend on the temperature of the module during the exposure. We observe changes in power as large as 5.8% for a 20 degrees C difference in light exposure temperature. These results lead us to conclude that for applications in which reproducibility and repeatability are critical, module temperature should be tightly controlled during light exposure.

  6. Thin-Film Reliability Trends Toward Improved Stability: Preprint

    SciTech Connect (OSTI)

    Jordan, D. C.; Kurtz, S. R.

    2011-07-01

    Long-term, stable performance of photovoltaic (PV) modules will be increasingly important to their successful penetration of the power grid. This paper summarizes more than 150 thin-film and more than 1700 silicon PV degradation rates (Rd) quoted in publications for locations worldwide. Partitioning the literature results by technology and date of installation statistical analysis shows an improvement in degradation rate especially for thin-film technologies in the last decade. A CIGS array deployed at NREL for more than 5 years that appears to be stable supports the literature trends. Indoor and outdoor data indicate undetectable change in performance (0.2+/-0.2 %/yr). One module shows signs of slight degradation from what appears to be an initial manufacturing defect, however it has not affected the overall system performance.

  7. Exploring High-Dimensional Data Space: Identifying Optimal Process Conditions in Photovoltaics: Preprint

    SciTech Connect (OSTI)

    Suh, C.; Glynn, S.; Scharf, J.; Contreras, M. A.; Noufi, R.; Jones, W. B.; Biagioni, D.

    2011-07-01

    We demonstrate how advanced exploratory data analysis coupled to data-mining techniques can be used to scrutinize the high-dimensional data space of photovoltaics in the context of thin films of Al-doped ZnO (AZO), which are essential materials as a transparent conducting oxide (TCO) layer in CuInxGa1-xSe2 (CIGS) solar cells. AZO data space, wherein each sample is synthesized from a different process history and assessed with various characterizations, is transformed, reorganized, and visualized in order to extract optimal process conditions. The data-analysis methods used include parallel coordinates, diffusion maps, and hierarchical agglomerative clustering algorithms combined with diffusion map embedding.

  8. Exploring High-Dimensional Data Space: Identifying Optimal Process Conditions in Photovoltaics

    SciTech Connect (OSTI)

    Suh, C.; Biagioni, D.; Glynn, S.; Scharf, J.; Contreras, M. A.; Noufi, R.; Jones, W. B.

    2011-01-01

    We demonstrate how advanced exploratory data analysis coupled to data-mining techniques can be used to scrutinize the high-dimensional data space of photovoltaics in the context of thin films of Al-doped ZnO (AZO), which are essential materials as a transparent conducting oxide (TCO) layer in CuIn{sub x}Ga{sub 1-x}Se{sub 2} (CIGS) solar cells. AZO data space, wherein each sample is synthesized from a different process history and assessed with various characterizations, is transformed, reorganized, and visualized in order to extract optimal process conditions. The data-analysis methods used include parallel coordinates, diffusion maps, and hierarchical agglomerative clustering algorithms combined with diffusion map embedding.

  9. Surface and interfacial reaction study of half cycle atomic layer deposited HfO{sub 2} on chemically treated GaSb surfaces

    SciTech Connect (OSTI)

    Zhernokletov, D. M.; Dong, H.; Brennan, B.; Kim, J.; Yakimov, M.; Tokranov, V.; Oktyabrsky, S.; Wallace, R. M.; Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080

    2013-04-01

    An in situ half-cycle atomic layer deposition/X-ray photoelectron spectroscopy (XPS) study was conducted in order to investigate the evolution of the HfO{sub 2} dielectric interface with GaSb(100) surfaces after sulfur passivation and HCl etching, designed to remove the native oxides. With the first pulses of tetrakis(dimethylamido)hafnium(IV) and water, a decrease in the concentration of antimony oxide states present on the HCl-etched surface is observed, while antimony sulfur states diminished below the XPS detection limit on sulfur passivated surface. An increase in the amount of gallium oxide/sulfide is seen, suggesting oxygen or sulfur transfers from antimony to gallium during antimony oxides/sulfides decomposition.

  10. Interplay of light transmission and catalytic exchange current in photoelectrochemical systems

    SciTech Connect (OSTI)

    Fountaine, Katherine T.; Lewerenz, Hans J.; Atwater, Harry A.

    2014-10-27

    We develop an analytic current-voltage expression for a variable junction photoelectrochemical (PEC) cell and use it to investigate and illustrate the influence of the optical and electrical properties of catalysts on the optoelectronic performance of PEC devices. Specifically, the model enables a simple, yet accurate accounting of nanostructured catalyst optical and electrical properties through incorporation of an optical transmission factor and active catalytic area factor. We demonstrate the utility of this model via the output power characteristics of an exemplary dual tandem solar cell with indium gallium phosphide and indium gallium arsenide absorbers with varying rhodium catalyst nanoparticle loading. The approach highlights the importance of considering interactions between independently optimized components for optimal PEC device design.

  11. Phase stable rare earth garnets

    SciTech Connect (OSTI)

    Kuntz, Joshua D.; Cherepy, Nerine J.; Roberts, Jeffery J.; Payne, Stephen A.

    2013-06-11

    A transparent ceramic according to one embodiment includes a rare earth garnet comprising A.sub.hB.sub.iC.sub.jO.sub.12, where h is 3.+-.10%, i is 2.+-.10%, and j is 3.+-.10%. A includes a rare earth element or a mixture of rare earth elements, B includes at least one of aluminum, gallium and scandium, and C includes at least one of aluminum, gallium and scandium, where A is at a dodecahedral site of the garnet, B is at an octahedral site of the garnet, and C is at a tetrahedral site of the garnet. In one embodiment, the rare earth garment has scintillation properties. A radiation detector in one embodiment includes a transparent ceramic as described above and a photo detector optically coupled to the rare earth garnet.

  12. Multi-spectral optical absorption in substrate-free nanowire arrays

    SciTech Connect (OSTI)

    Zhang, Junpeng; Chia, Andrew; Boulanger, Jonathan; LaPierre, Ray; Dhindsa, Navneet; Khodadad, Iman; Saini, Simarjeet

    2014-09-22

    A method is presented of fabricating gallium arsenide (GaAs) nanowire arrays of controlled diameter and period by reactive ion etching of a GaAs substrate containing an indium gallium arsenide (InGaP) etch stop layer, allowing the precise nanowire length to be controlled. The substrate is subsequently removed by selective etching, using the same InGaP etch stop layer, to create a substrate-free GaAs nanowire array. The optical absorptance of the nanowire array was then directly measured without absorption from a substrate. We directly observe absorptance spectra that can be tuned by the nanowire diameter, as explained with rigorous coupled wave analysis. These results illustrate strong optical absorption suitable for nanowire-based solar cells and multi-spectral absorption for wavelength discriminating photodetectors. The solar-weighted absorptance above the bandgap of GaAs was 94% for a nanowire surface coverage of only 15%.

  13. Synthesis, morphology and optical properties of GaN and AlGaN semiconductor nanostructures

    SciTech Connect (OSTI)

    Kuppulingam, B. Singh, Shubra Baskar, K.

    2014-04-24

    Hexagonal Gallium Nitride (GaN) and Aluminum Gallium Nitride (AlGaN) nanoparticles were synthesized by sol-gel method using Ethylene Diamine Tetra Acetic acid (EDTA) complex route. Powder X-ray diffraction (PXRD) analysis confirms the hexagonal wurtzite structure of GaN and Al{sub 0.25}Ga{sub 0.75}N nanoparticles. Surface morphology and elemental analysis were carried out by Scanning Electron Microscope (SEM) and Energy Dispersive X-ray spectroscopy (EDX). The room temperature Photoluminescence (PL) study shows the near band edge emission for GaN at 3.35 eV and at 3.59 eV for AlGaN nanoparticles. The Aluminum (Al) composition of 20% has been obtained from PL emission around 345 nm.

  14. The interaction between divacancies and shallow dopants in irradiated Ge:Sn

    SciTech Connect (OSTI)

    Khirunenko, L. I.; Pomozov, Yu. V.; Sosnin, M. G.; Abrosimov, N. V.; Riemann, H.

    2014-02-21

    It has been found that upon annealing of irradiated Ge doped with gallium and Sn simultaneously with disappearance of divacancies V{sub 2}{sup 0} the appearance of the new absorption spectrum consisting of sharp lines was observed. The spectrum is identical to the absorption spectrum of gallium. It is shown that the defect, to which the new spectrum corresponds, has hydrogen-like properties. The distances between the lines in the spectrum are in good agreement with those predicted by effective-mass theory. The appearance of Fano resonance in the continuum region in addition to intracenter transitions of the defect was detected. The defect found is identified as SnV{sub 2}{sup 0}Ga. The binding energy for the ground state of the SnV{sub 2}{sup 0}Ga centers has been estimated.

  15. Hydrogenated indium oxide window layers for high-efficiency Cu(In,Ga)Se{sub 2} solar cells

    SciTech Connect (OSTI)

    Jäger, Timo Romanyuk, Yaroslav E.; Nishiwaki, Shiro; Bissig, Benjamin; Pianezzi, Fabian; Fuchs, Peter; Gretener, Christina; Tiwari, Ayodhya N.; Döbeli, Max

    2015-05-28

    High mobility hydrogenated indium oxide is investigated as a transparent contact for thin film Cu(In,Ga)Se{sub 2} (CIGS) solar cells. Hydrogen doping of In{sub 2}O{sub 3} thin films is achieved by injection of H{sub 2}O water vapor or H{sub 2} gas during the sputter process. As-deposited amorphous In{sub 2}O{sub 3}:H films exhibit a high electron mobility of ∼50 cm{sup 2}/Vs at room temperature. A bulk hydrogen concentration of ∼4 at. % was measured for both optimized H{sub 2}O and H{sub 2}-processed films, although the H{sub 2}O-derived film exhibits a doping gradient as detected by elastic recoil detection analysis. Amorphous IOH films are implemented as front contacts in CIGS based solar cells, and their performance is compared with the reference ZnO:Al electrodes. The most significant feature of IOH containing devices is an enhanced open circuit voltage (V{sub OC}) of ∼20 mV regardless of the doping approach, whereas the short circuit current and fill factor remain the same for the H{sub 2}O case or slightly decrease for H{sub 2}. The overall power conversion efficiency is improved from 15.7% to 16.2% by substituting ZnO:Al with IOH (H{sub 2}O) as front contacts. Finally, stability tests of non-encapsulated solar cells in dry air at 80 °C and constant illumination for 500 h demonstrate a higher stability for IOH-containing devices.

  16. Space-and-Time Resolved Spectroscopy of Single GaN Nanowires

    SciTech Connect (OSTI)

    Upadhya, Prashanth C.; Martinez, Julio A.; Li, Qiming; Wang, George T.; Swartzentruber, Brian S.; Taylor, Antoinette J.; Prasankumar, Rohit P.

    2015-07-01

    Gallium nitridenanowires have garnered much attention in recent years due to their attractive optical and electrical properties. An understanding of carrier transport, relaxation, and recombination in these quasi-one-dimensional nanosystems is therefore important in optimizing them for various applications. We present ultrafast optical microscopic measurements on single GaNnanowires. Furthermore, our experiments, performed while varying the light polarization,excitation fluence, and position, give insight into the mechanisms governing carrier dynamics in these nanosystems.

  17. Sandia National Laboratories: Power Electronics

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

    Power Electronics Sensors Power electronics is the application of solid-state electronics for routing, control, and conversion of electrical power. Custom Solutions Wide-Bandgap Wide-bandgap semiconductor materials such as silicon carbide (SiC) and gallium nitride (GaN) have the potential to revolutionize the field of power electronics. Sandia National Laboratories is well-suited to understand both performance and reliability in wide-bandgap power electronics. Understanding Material Properties

  18. Liquid metal cooling of synchrotron optics

    SciTech Connect (OSTI)

    Smither, R.K.

    1992-09-01

    The installation of insertion devices at existing synchrotron facilities around the world has stimulated the development of new ways to cool the optical elements in the associated x-ray beamlines. Argonne has been a leader in the development of liquid metal cooling for high heat load x-ray optics for the next generation of synchrotron facilities. The high thermal conductivity, high volume specific heat, low kinematic viscosity, and large working temperature range make liquid metals a very efficient heat transfer fluid. A wide range of liquid metals were considered in the initial phase of this work. The most promising liquid metal cooling fluid identified to date is liquid gallium, which appears to have all the desired properties and the fewest number of undesired features of the liquid metals examined. Besides the special features of liquid metals that make them good heat transfer fluids, the very low vapor pressure over a large working temperature range make liquid gallium an ideal cooling fluid for use in a high vacuum environment. A leak of the liquid gallium into the high vacuum and even into very high vacuum areas will not result in any detectable vapor pressure and may even improve the vacuum environment as the liquid gallium combines with any water vapor or oxygen present in the system. The practical use of a liquid metal for cooling silicon crystals and other high heat load applications depends on having a convenient and efficient delivery system. The requirements for a typical cooling system for a silicon crystal used in a monochromator are pumping speeds of 2 to 5 gpm (120 cc per sec to 600 cc per sec) at pressures up to 100 psi.

  19. Main Title 32pt

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

    Electroactive Ionic Liquids: A New Approach to Flow Batteries 2. Gallium Nitride Substrates for Power Electronics: Electrochemical Solution Growth Karen Waldrip, PhD Advanced Power Sources R&D Sandia National Labs, Albuquerque, NM knwaldr@sandia.gov Sandia National Laboratories' Programs Electroactive Ionic Liquids: A New Approach To Flow Batteries Date Travis Anderson David Ingersoll Chad Staiger Karen Waldrip Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed

  20. Hafnium nitride buffer layers for growth of GaN on silicon

    DOE Patents [OSTI]

    Armitage, Robert D.; Weber, Eicke R.

    2005-08-16

    Gallium nitride is grown by plasma-assisted molecular-beam epitaxy on (111) and (001) silicon substrates using hafnium nitride buffer layers. Wurtzite GaN epitaxial layers are obtained on both the (111) and (001) HfN/Si surfaces, with crack-free thickness up to 1.2 {character pullout}m. However, growth on the (001) surface results in nearly stress-free films, suggesting that much thicker crack-free layers could be obtained.

  1. PROJECT PROFILE: Mechanically Stacked Hybrid Photovoltaic Tandems |

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

    Department of Energy Mechanically Stacked Hybrid Photovoltaic Tandems PROJECT PROFILE: Mechanically Stacked Hybrid Photovoltaic Tandems Funding Opportunity: SuNLaMP SunShot Subprogram: Photovoltaics Location: National Renewable Energy Laboratory, Golden, CO Amount Awarded: $999,999 Tandem cell architectures present a path toward higher module efficiencies over single junction designs. This project will develop a gallium indium phosphide (GaInP) on silicon mechanically stacked voltage-matched

  2. PROJECT PROFILE: Silicon-Based Tandem Solar Cells | Department of Energy

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

    Silicon-Based Tandem Solar Cells PROJECT PROFILE: Silicon-Based Tandem Solar Cells Funding Opportunity: SuNLaMP SunShot Subprogram: Photovoltaics Location: National Renewable Energy Laboratory, Golden, CO Amount Awarded: $1,500,000 The project will demonstrate bonded gallium indium phosphide (GaInP) on silicon tandem cells, evaluate the advantages and disadvantages of this method of forming higher-efficiency tandem cells, and compare two- and three-terminal device configurations. APPROACH In

  3. Slide 1

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

    High Temperature-tolerant and Radiation-resistant In- core Neutron Sensor for Advanced Reactors Lei R. Cao The Ohio State University Cao.152@osu.edu September 18, 2014 2 Project Overview  Goal and Objectives To develop a small and reliable gallium nitride (GaN) neutron sensor capable of withstanding high neutron fluences and high temperatures, while isolating gamma background. This project will provide an understanding of the fundamental material properties and electronic response of a GaN

  4. Radiopharmaceuticals for imaging the heart

    DOE Patents [OSTI]

    Green, M.A.; Tsang, B.W.

    1994-06-28

    Radiopharmaceuticals for imaging myocardial tissues are prepared by forming lipophilic, cationic complexes of radioactive metal ions with metal chelating ligands comprising the Schiff base adducts of triamines and tetraamines with optionally substituted salicylaldehydes. The lipophilic, cationic, radioactive complexes of the invention exhibit high uptake and retention in myocardial tissues. Preferred gallium-68(III) complexes in accordance with this invention can be used to image the heart using positron emission tomography. 6 figures.

  5. Radiopharmaceuticals for imaging the heart

    DOE Patents [OSTI]

    Green, Mark A.; Tsang, Brenda W.

    1994-01-01

    Radiopharmaceuticals for imaging myocardial tissues are prepared by forming lipophilic, cationic complexes of radioactive metal ions with metal chelating ligands comprising the Schiff base adducts of triamines and tetraamines with optionally substituted salicylaldehydes. The lipophilic, cationic, radioactive complexes of the invention exhibit high uptake and retention in myocardial tissues. Preferred gallium-68(III) complexes in accordance with this invention can be used to image the heart using positron emission tomography.

  6. Solar neutrinos: theory vs experiment

    SciTech Connect (OSTI)

    Haxton, W.C.

    1991-01-01

    I review the standard solar model, the disparities between its predictions and the solar neutrino flux measurements of the Homestake and Kamioka II collaborations, and possible particle physics resolutions of this puzzle. The effects of matter, including density fluctuations and turbulence, on solar neutrino oscillations are reviewed, including possibilities for generating time variations in the solar neutrino flux. Finally, I consider possible outcomes and implications of the SAGE/GALLEX gallium experiments.

  7. Space-and-time resolved spectroscopy of single GaN nanowires

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

    Upadhya, Prashanth C.; Martinez, Julio A.; Li, Qiming; Wang, George T.; Swartzentruber, Brian S.; Taylor, Antoinette J.; Prasankumar, Rohit P.

    2015-06-30

    Gallium nitridenanowires have garnered much attention in recent years due to their attractive optical and electrical properties. An understanding of carrier transport, relaxation, and recombination in these quasi-one-dimensional nanosystems is therefore important in optimizing them for various applications. We present ultrafast optical microscopic measurements on single GaNnanowires. Furthermore, our experiments, performed while varying the light polarization,excitation fluence, and position, give insight into the mechanisms governing carrier dynamics in these nanosystems.

  8. Summer 2011 Intern Project- Eric Ling | Center for Energy Efficient

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

    Materials Eric Ling THERMOELECTRIC PROPERTIES OF DOPED InGaAs Eric Ling Physics and Mathamatics UC Santa Barbara Mentor: Borzoyeh Shojaei Faculty Advisor: Chris Pamlstrom Department: Electrical and Computer Engineering In recent history, thermeoelectrics have shown to be promising materials for energy conversion via wasted heat to electricity. One such material, indium gallium arsenide (InGaAs), may possess a high electrical conductivity term in the thermoelectric figure of merit when doped

  9. Building America Case Study: Mockup Small-Diameter Air Distribution System (Fact Sheet), NREL (National Renewable Energy Laboratory)

    Office of Environmental Management (EM)

    Bright Lights and Even Brighter Ideas Bright Lights and Even Brighter Ideas July 3, 2013 - 2:04pm Addthis Kim Kisslinger, a researcher at Brookhaven Lab's Center for Functional Nanomaterials seen here with a focused-ion beam instrument, reduced the indium gallium nitride (InGaN) samples to a thickness of just 20 nanometers to prepare them for electron microscopy. | Photo courtesy of Brookhaven National Laboratory. Kim Kisslinger, a researcher at Brookhaven Lab's Center for Functional

  10. Phosphors containing boron and metals of Group IIIA and IIIB

    DOE Patents [OSTI]

    Setlur, Anant Achyut; Srivastava, Alok Mani; Comanzo, Holly Ann; Manivannan, Venkatesan

    2006-10-31

    A phosphor comprises: (a) at least a first metal selected from the group consisting of yttrium and elements of lanthanide series other than europium; (b) at least a second metal selected from the group consisting of aluminum, gallium, indium, and scandium; (c) boron; and (d) europium. The phosphor is used in light source that comprises a UV radiation source to convert UV radiation to visible light.

  11. NREL Spurred the Success of Multijunction Solar Cells (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2013-08-01

    Many scientists once believed that high-quality gallium indium phosphide (GaInP) alloys could not be grown for use as semiconductors because the alloys would separate. However, researchers at the National Renewable Energy Laboratory (NREL) thought differently, and they employed GaInP in a material combination that allowed the multijunction cell to flourish. The multijunction cell is now the workhorse that powers satellites and the catalyst for renewed interest in concentrator photovoltaic products.

  12. Colorado School of Mines Researchers Win Patent | Critical Materials

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

    Institute News News releases CMI in the news News archive CMI social media Colorado School of Mines Researchers Win Patent The Coloroado School of Mines 2013 highlights include news that Prof. Corby Anderson along with co-inventors Dr. Paul Miranda of Thompson Creek minerals and Dr. Ed Rosenberg of University of Montana were granted a US patent for styrene based ion exchange resins with oxine functionalized groups. The original work was focused on separating iron and gallium, but the

  13. Electronic and structural characteristics of zinc-blende wurtzite biphasic homostructure GaN nanowires

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

    Jacobs, Benjamin W.; Ayres, Virginia M.; Petkov, Mihail P.; Halpern, Joshua B.; He, Maoqi; Baczewski, Andrew D.; McElroy, Kaylee; Crimp, Martin A.; Zhang, Jiaming; Shaw, Harry C.

    2016-02-01

    Here, we report a new biphasic crystalline wurtzite/zinc-blende homostructure in gallium nitride nanowires. Cathodoluminescence was used to quantitatively measure the wurtzite and zinc-blende band gaps. High-resolution transmission electron microscopy was used to identify distinct wurtzite and zinc-blende crystalline phases within single nanowires through the use of selected area electron diffraction, electron dispersive spectroscopy, electron energy loss spectroscopy, and fast Fourier transform techniques. A mechanism for growth is identified.

  14. Ab initio study of semiconductor atoms impurities in zigzag edge (10,0) carbon nanotubes

    SciTech Connect (OSTI)

    Muttaqien, Fahdzi Suprijadi

    2015-04-16

    The substitutional impurities in zigzag edge (10,0) carbon nanotubes have been studied by using first principles calculations. Silicon (Si), gallium (Ga), and arsenic (As) atom have been chosen as semiconductor based-atom for replacing carbon atoms in CNTs surface. The silicon atom changes the energy gap of pristine zigzag (10,0) CNT, it is 0.19 eV more narrow than that of pristine CNT. Geometrically, the silicon atom creates sp{sup 3} bond with three adjacent carbon atoms, where the tetrahedral form of its sp{sup 3} bond is consisted of free unoccupied state. The silicon atom does not induce magnetism to zigzag CNT. Due to gallium (Ga) and arsenic (As) atom substitution, the zigzag CNT becomes metallic and has magnetic moment of 1?{sub B}. The valance and conduction band are crossed each other, then the energy gap is vanished. The electronic properties of GaAs-doped CNT are dominantly affected by gallium atom and its magnetic properties are dominantly affected by arsenic atom. These results prove that the CNT with desired properties can be obtained with substitutional impurities without any giving structural defect.

  15. High-efficiency solar cell and method for fabrication

    DOE Patents [OSTI]

    Hou, H.Q.; Reinhardt, K.C.

    1999-08-31

    A high-efficiency 3- or 4-junction solar cell is disclosed with a theoretical AM0 energy conversion efficiency of about 40%. The solar cell includes p-n junctions formed from indium gallium arsenide nitride (InGaAsN), gallium arsenide (GaAs) and indium gallium aluminum phosphide (InGaAlP) separated by n-p tunnel junctions. An optional germanium (Ge) p-n junction can be formed in the substrate upon which the other p-n junctions are grown. The bandgap energies for each p-n junction are tailored to provide substantially equal short-circuit currents for each p-n junction, thereby eliminating current bottlenecks and improving the overall energy conversion efficiency of the solar cell. Additionally, the use of an InGaAsN p-n junction overcomes super-bandgap energy losses that are present in conventional multi-junction solar cells. A method is also disclosed for fabricating the high-efficiency 3- or 4-junction solar cell by metal-organic chemical vapor deposition (MOCVD). 4 figs.

  16. High-efficiency solar cell and method for fabrication

    DOE Patents [OSTI]

    Hou, Hong Q.; Reinhardt, Kitt C.

    1999-01-01

    A high-efficiency 3- or 4-junction solar cell is disclosed with a theoretical AM0 energy conversion efficiency of about 40%. The solar cell includes p-n junctions formed from indium gallium arsenide nitride (InGaAsN), gallium arsenide (GaAs) and indium gallium aluminum phosphide (InGaAlP) separated by n-p tunnel junctions. An optional germanium (Ge) p-n junction can be formed in the substrate upon which the other p-n junctions are grown. The bandgap energies for each p-n junction are tailored to provide substantially equal short-circuit currents for each p-n junction, thereby eliminating current bottlenecks and improving the overall energy conversion efficiency of the solar cell. Additionally, the use of an InGaAsN p-n junction overcomes super-bandgap energy losses that are present in conventional multi-junction solar cells. A method is also disclosed for fabricating the high-efficiency 3- or 4-junction solar cell by metal-organic chemical vapor deposition (MOCVD).

  17. Formation of manganese {delta}-doped atomic layer in wurtzite GaN

    SciTech Connect (OSTI)

    Shi Meng; Chinchore, Abhijit; Wang Kangkang; Mandru, Andrada-Oana; Liu Yinghao; Smith, Arthur R.

    2012-09-01

    We describe the formation of a {delta}-doped manganese layer embedded within c-plane wurtzite gallium nitride using a special molecular beam epitaxy growth process. Manganese is first deposited on the gallium-poor GaN (0001) surface, forming a {radical}(3) Multiplication-Sign {radical}(3)-R30 Degree-Sign reconstructed phase. This well-defined surface reconstruction is then nitrided using plasma nitridation, and gallium nitride is overgrown. The manganese content of the {radical}(3) Multiplication-Sign {radical}(3)-R30 Degree-Sign phase, namely one Mn per each {radical}(3) Multiplication-Sign {radical}(3)-R30 Degree-Sign unit cell, implies that the MnGaN alloy layer has a Mn concentration of up to 33%. The structure and chemical content of the surface are monitored beginning from the initial growth stage up through the overgrowth of 20 additional monolayers (MLs) of GaN. An exponential-like drop-off of the Mn signal with increasing GaN monolayers, as measured by Auger electron spectroscopy, indicates that the highly concentrated Mn layer remains at the {delta}-doped interface. A model of the resultant {delta}-doped structure is formulated based on the experimental data, and implications for possible spintronic applications are discussed.

  18. Monolayer PtSe 2 , a New Semiconducting Transition-Metal-Dichalcogenide, Epitaxially Grown by Direct Selenization of Pt

    SciTech Connect (OSTI)

    Wang, Yeliang; Li, Linfei; Yao, Wei; Song, Shiru; Sun, J. T.; Pan, Jinbo; Ren, Xiao; Li, Chen; Okunishi, Eiji; Wang, Yu-Qi; Wang, Eryin; Shao, Yan; Zhang, Y. Y.; Yang, Hai-tao; Schwier, Eike F.; Iwasawa, Hideaki; Shimada, Kenya; Taniguchi, Masaki; Cheng, Zhaohua; Zhou, Shuyun; Du, Shixuan; Pennycook, Stephen J.; Pantelides, Sokrates T.; Gao, Hong-Jun

    2015-05-21

    For single-layer transition-metal dichalcogenides (TMDs) receive significant attention due to their intriguing physical properties for both fundamental research and potential applications in electronics, optoelectronics, spintronics, catalysis, and so on. Here, we demonstrate the epitaxial growth of high-quality single-crystal, monolayer platinum diselenide (PtSe2), a new member of the layered TMDs family, by a single step of direct selenization of a Pt(111) substrate. We found that a combination of atomic-resolution experimental characterizations and first-principle theoretic calculations reveals the atomic structure of the monolayer PtSe2/Pt(111). Angle-resolved photoemission spectroscopy measurements confirm for the first time the semiconducting electronic structure of monolayer PtSe2 (in contrast to its semimetallic bulk counterpart). The photocatalytic activity of monolayer PtSe2 film is evaluated by a methylene-blue photodegradation experiment, demonstrating its practical application as a promising photocatalyst. Moreover, circular polarization calculations predict that monolayer PtSe2 has also potential applications in valleytronics.

  19. Optical properties and defect levels in a surface layer found on CuInSe{sub 2} thin films

    SciTech Connect (OSTI)

    Abulfotuh, F.; Wangensteen, T.; Ahrenkiel, R.; Kazmerski, L.L.

    1996-05-01

    In this paper the authors have used photoluminescence (PL) and wavelength scanning ellipsometry (WSE) to clarify the relationship among the electro-optical properties of copper indium diselenide (CIS) thin films, the type and origin of dominant defect states, and device performance. The PL study has revealed several shallow acceptor and donor levels dominating the semiconductor. PL emission from points at different depths from the surface of the CIS sample has been obtained by changing the angle of incidence of the excitation laser beam. The resulting data were used to determine the dominant defect states as a function of composition gradient at the surface of the chalcopyrite compound. The significance of this type of measurement is that it allowed the detection of a very thin layer with a larger bandgap (1.15-1.26 eV) than the CIS present on the surface of the CIS thin films. The presence of this layer has been correlated by several groups to improvement of the CIS cell performance. An important need that results from detecting this layer on the surface of the CIS semiconductor is the determination of its thickness and optical constants (n, k) as a function of wavelength. The thickness of this surface layer is about 500 {Angstrom}.

  20. Monolayer PtSe 2 , a New Semiconducting Transition-Metal-Dichalcogenide, Epitaxially Grown by Direct Selenization of Pt

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

    Wang, Yeliang; Li, Linfei; Yao, Wei; Song, Shiru; Sun, J. T.; Pan, Jinbo; Ren, Xiao; Li, Chen; Okunishi, Eiji; Wang, Yu-Qi; et al

    2015-05-21

    For single-layer transition-metal dichalcogenides (TMDs) receive significant attention due to their intriguing physical properties for both fundamental research and potential applications in electronics, optoelectronics, spintronics, catalysis, and so on. Here, we demonstrate the epitaxial growth of high-quality single-crystal, monolayer platinum diselenide (PtSe2), a new member of the layered TMDs family, by a single step of direct selenization of a Pt(111) substrate. We found that a combination of atomic-resolution experimental characterizations and first-principle theoretic calculations reveals the atomic structure of the monolayer PtSe2/Pt(111). Angle-resolved photoemission spectroscopy measurements confirm for the first time the semiconducting electronic structure of monolayer PtSe2 (in contrastmore » to its semimetallic bulk counterpart). The photocatalytic activity of monolayer PtSe2 film is evaluated by a methylene-blue photodegradation experiment, demonstrating its practical application as a promising photocatalyst. Moreover, circular polarization calculations predict that monolayer PtSe2 has also potential applications in valleytronics.« less

  1. NREL, CSEM Jointly Set New Efficiency Record with Dual-Junction Solar Cell (Fact Sheet), Highlights in Research & Development, NREL (National Renewable Energy Laboratory)

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

    Scientists set a new world record for converting non-concentrated sunlight into electricity using a dual-junction III-V/Si solar cell. A joint effort between the National Renewable Energy Laboratory (NREL) and the Swiss Center for Electronics and Microtechnology (CSEM) has resulted in a novel tandem solar cell that operates at 29.8% conversion efficiency under 1-sun conditions. The new solar cell technology combines NREL's 1.8-eV gallium indium phosphide (GaInP) technology as a top cell and

  2. NREL: Photovoltaics Research - Thin Film Photovoltaic Partnership Project

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

    Thin Film Photovoltaic Partnership Project NREL's Thin Film Photovoltaic (PV) Partnership Project led R&D on emerging thin-film solar technologies in the United States from 1994 to 2009. The project made many advances in thin-film PV technologies that allowed the United States to attain world leadership in this area of solar technology. Three national R&D teams focused on thin-film semiconductor materials: amorphous silicon (a-Si), cadmium telluride (CdTe), and copper indium gallium

  3. Highly transparent ammonothermal bulk GaN substrates

    SciTech Connect (OSTI)

    Jiang, WK; Ehrentraut, D; Downey, BC; Kamber, DS; Pakalapati, RT; Do Yoo, H; D'Evelyn, MP

    2014-10-01

    A novel apparatus has been employed to grow ammonothermal (0001) gallium nitride (GaN) with diameters up to 2 in The crystals have been characterized by x-ray diffraction rocking-curve (XRC) analysis, optical and scanning electron microscopy (SEM), cathodoluminescence (CL), and optical spectroscopy. High crystallinity GaN with FWHM values about 20-50 arcsec and dislocation densities below 1 x 10(5) cm(-2) have been obtained. High optical transmission was achieved with an optical absorption coefficient below 1 cm(-1) at a wavelength of 450 nm. (C) 2014 Elsevier B.V. All rights reserved.

  4. Production Of High Specific Activity Copper-67

    DOE Patents [OSTI]

    Jamriska, Sr., David J.; Taylor, Wayne A.; Ott, Martin A.; Fowler, Malcolm; Heaton, Richard C.

    2003-10-28

    A process for the selective production and isolation of high specific activity Cu.sup.67 from proton-irradiated enriched Zn.sup.70 target comprises target fabrication, target irradiation with low energy (<25 MeV) protons, chemical separation of the Cu.sup.67 product from the target material and radioactive impurities of gallium, cobalt, iron, and stable aluminum via electrochemical methods or ion exchange using both anion and cation organic ion exchangers, chemical recovery of the enriched Zn.sup.70 target material, and fabrication of new targets for re-irradiation is disclosed.

  5. Production Of High Specific Activity Copper-67

    DOE Patents [OSTI]

    Jamriska, Sr., David J.; Taylor, Wayne A.; Ott, Martin A.; Fowler, Malcolm; Heaton, Richard C.

    2002-12-03

    A process for the selective production and isolation of high specific activity cu.sup.67 from proton-irradiated enriched Zn.sup.70 target comprises target fabrication, target irradiation with low energy (<25 MeV) protons, chemical separation of the Cu.sup.67 product from the target material and radioactive impurities of gallium, cobalt, iron, and stable aluminum via electrochemical methods or ion exchange using both anion and cation organic ion exchangers, chemical recovery of the enriched Zn.sup.70 target material, and fabrication of new targets for re-irradiation is disclosed.

  6. Ferroelectric switching of poly(vinylidene difluoride-trifluoroethylene) in metal-ferroelectric-semiconductor non-volatile memories with an amorphous oxide semiconductor

    SciTech Connect (OSTI)

    Gelinck, G. H.; Breemen, A. J. J. M. van; Cobb, B.

    2015-03-02

    Ferroelectric polarization switching of poly(vinylidene difluoride-trifluoroethylene) is investigated in different thin-film device structures, ranging from simple capacitors to dual-gate thin-film transistors (TFT). Indium gallium zinc oxide, a high mobility amorphous oxide material, is used as semiconductor. We find that the ferroelectric can be polarized in both directions in the metal-ferroelectric-semiconductor (MFS) structure and in the dual-gate TFT under certain biasing conditions, but not in the single-gate thin-film transistors. These results disprove the common belief that MFS structures serve as a good model system for ferroelectric polarization switching in thin-film transistors.

  7. Oxidation of ultrathin GaSe

    SciTech Connect (OSTI)

    Thomas Edwin Beechem; McDonald, Anthony E.; Ohta, Taisuke; Howell, Stephen W.; Kalugin, Nikolai G.; Kowalski, Brian M.; Brumbach, Michael T.; Spataru, Catalin D.; Pask, Jesse A.

    2015-10-26

    Oxidation of exfoliated gallium selenide (GaSe) is investigated through Raman, photoluminescence, Auger, and X-ray photoelectron spectroscopies. Photoluminescence and Raman intensity reductions associated with spectral features of GaSe are shown to coincide with the emergence of signatures emanating from the by-products of the oxidation reaction, namely, Ga2Se3 and amorphous Se. Furthermore, photoinduced oxidation is initiated over a portion of a flake highlighting the potential for laser based patterning of two-dimensional heterostructures via selective oxidation.

  8. Red light-emitting diodes based on InP/GaP quantum dots

    SciTech Connect (OSTI)

    Hatami, F.; Lordi, V.; Harris, J.S.; Kostial, H.; Masselink, W.T.

    2005-05-01

    The growth, fabrication, and device characterization of InP quantum-dot light-emitting diodes based on GaP are described and discussed. The diode structures are grown on gallium phosphide substrates using gas-source molecular-beam epitaxy and the active region of the diode consists of self-assembled InP quantum dots embedded in a GaP matrix. Red electroluminescence originating from direct band-gap emission from the InP quantum dots is observed at low temperatures.With increasing temperature, however, the emission line shifts to the longer wavelength. The emission light is measured to above room temperature.

  9. Improved method of preparing p-i-n junctions in amorphous silicon semiconductors

    DOE Patents [OSTI]

    Madan, A.

    1984-12-10

    A method of preparing p/sup +/-i-n/sup +/ junctions for amorphous silicon semiconductors includes depositing amorphous silicon on a thin layer of trivalent material, such as aluminum, indium, or gallium at a temperature in the range of 200/sup 0/C to 250/sup 0/C. At this temperature, the layer of trivalent material diffuses into the amorphous silicon to form a graded p/sup +/-i junction. A layer of n-type doped material is then deposited onto the intrinsic amorphous silicon layer in a conventional manner to finish forming the p/sup +/-i-n/sup +/ junction.

  10. Fundamental studies of passivity and passivity breakdown. Final report, [September 1993--September 1994

    SciTech Connect (OSTI)

    Macdonald, D.D.; Urquidi-Macdonald, M.

    1994-02-21

    Purpose is to understand the mechanisms for growth and breakdown of passive films on metal and alloy surfaces in aqueous medium; a secondary goal is to devise methods for predicting localized corrosion damage in industrial systems. Tasks currently being studied are: formation of bilayer structures in passive films on metals and alloys; passivity breakdown on solid vs. liquid gallium; roles of alloying elements in passivity breakdown; electrochemical impedance spectroscopy of passive films; electronic structure of passive oxide films; photoelectrochemical impedance spectroscopy of passive films; and kinetics of localized attack.

  11. NREL Scientists Spurred the Success of Multijunction Solar Cells (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2012-09-01

    Before 1984, many scientists believed that high-quality gallium indium phosphide (GaInP) alloys could not be grown for use as semiconductors because the alloys would separate. One researcher at the Solar Energy Research Institute (SERI) thought differently. His name was Jerry Olson, and his innovative thinking changed solar history. Olson identified a material combination that allowed the multijunction cell to flourish. It is now the workhorse that powers satellites and the catalyst for renewed interest in concentrator photovoltaic (CPV) products.

  12. Conductivity based on selective etch for GaN devices and applications thereof

    DOE Patents [OSTI]

    Zhang, Yu; Sun, Qian; Han, Jung

    2015-12-08

    This invention relates to methods of generating NP gallium nitride (GaN) across large areas (>1 cm.sup.2) with controlled pore diameters, pore density, and porosity. Also disclosed are methods of generating novel optoelectronic devices based on porous GaN. Additionally a layer transfer scheme to separate and create free-standing crystalline GaN thin layers is disclosed that enables a new device manufacturing paradigm involving substrate recycling. Other disclosed embodiments of this invention relate to fabrication of GaN based nanocrystals and the use of NP GaN electrodes for electrolysis, water splitting, or photosynthetic process applications.

  13. Oxidation of ultrathin GaSe

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

    Thomas Edwin Beechem; McDonald, Anthony E.; Ohta, Taisuke; Howell, Stephen W.; Kalugin, Nikolai G.; Kowalski, Brian M.; Brumbach, Michael T.; Spataru, Catalin D.; Pask, Jesse A.

    2015-10-26

    Oxidation of exfoliated gallium selenide (GaSe) is investigated through Raman, photoluminescence, Auger, and X-ray photoelectron spectroscopies. Photoluminescence and Raman intensity reductions associated with spectral features of GaSe are shown to coincide with the emergence of signatures emanating from the by-products of the oxidation reaction, namely, Ga2Se3 and amorphous Se. Furthermore, photoinduced oxidation is initiated over a portion of a flake highlighting the potential for laser based patterning of two-dimensional heterostructures via selective oxidation.

  14. Sub-Microsecond Decay Time Phosphors for Pressure Sensitive Paint Applications

    SciTech Connect (OSTI)

    Allison, S.W.

    2001-03-22

    The results suggest that garnet phosphors can be engineered to function thermographically over desired temperature ranges by adjusting gallium content. Substituting gadolinium for the yttrium in the host matrix also has an effect but it is not as large. A silicate phosphor showed the greatest temperature dependence though it could not be excited to fluoresce by a blue LED. All the garnet phosphors could be excited with such a blue source. Two phosphors tested showed an increase in intensity with temperature. Other garnet and silicate materials as mentioned above will be tested in the future. In addition, some perovskite phosphors, such as GdAlO{sub 3}:Ce, will also be investigated.

  15. Solar neutrinos: Theoretical status

    SciTech Connect (OSTI)

    Haxton, W.C.

    1991-01-01

    I review the standard solar model, the disparities between its predictions an the solar neutrino flux measurements of the Homestake and Kamioka 2 collaborations, and possible particle physics resolutions of this puzzle. The effects of matter, including density fluctuations and turbulence, on solar neutrino oscillations are explained by building analogies with more familiar atomic physics phenomena. These and other mechanisms are considered as possible explanations for time variations in the solar neutrino flux. Finally, I consider possible outcomes and implications of the SAGE/GALLEX gallium experiments.

  16. Short-baseline electron neutrino disappearance, tritium beta decay, and neutrinoless double-beta decay

    SciTech Connect (OSTI)

    Giunti, Carlo; Laveder, Marco [INFN, Sezione di Torino, Via P. Giuria 1, I-10125 Torino (Italy); Dipartimento di Fisica G. Galilei, Universita di Padova, and INFN, Sezione di Padova, Via F. Marzolo 8, I-35131 Padova (Italy)

    2010-09-01

    We consider the interpretation of the MiniBooNE low-energy anomaly and the gallium radioactive source experiments anomaly in terms of short-baseline electron neutrino disappearance in the framework of 3+1 four-neutrino mixing schemes. The separate fits of MiniBooNE and gallium data are highly compatible, with close best-fit values of the effective oscillation parameters {Delta}m{sup 2} and sin{sup 2}2{theta}. The combined fit gives {Delta}m{sup 2}(greater-or-similar sign)0.1 eV{sup 2} and 0.11(less-or-similar sign)sin{sup 2}2{theta}(less-or-similar sign)0.48 at 2{sigma}. We consider also the data of the Bugey and Chooz reactor antineutrino oscillation experiments and the limits on the effective electron antineutrino mass in {beta} decay obtained in the Mainz and Troitsk tritium experiments. The fit of the data of these experiments limits the value of sin{sup 2}2{theta} below 0.10 at 2{sigma}. Considering the tension between the neutrino MiniBooNE and gallium data and the antineutrino reactor and tritium data as a statistical fluctuation, we perform a combined fit which gives {Delta}m{sup 2}{approx_equal}2 eV and 0.01(less-or-similar sign)sin{sup 2}2{theta}(less-or-similar sign)0.13 at 2{sigma}. Assuming a hierarchy of masses m{sub 1}, m{sub 2}, m{sub 3}<gallium data and the antineutrino reactor and tritium data with different mixings in the neutrino and antineutrino sectors. We find a 2.6{sigma} indication of a mixing angle asymmetry.

  17. Event Archives | Solid State Solar Thermal Energy Conversion

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

    Event Archives Seminar S3TEC - Thermal Engineering of GaN Semiconductor Devices Friday, Jul 22, 2016 12:00 am 3-270 The development of gallium nitride (GaN) on a variety of substrates from SiC to diamond is under development to create high power RF technologies for advanced communications and power electronic devices. In general, GaN devices can accommodate high operational frequencies, high junction... more Seminar Cross Cutting seminar series: Generation, transport and relaxation of

  18. Journal Cover Stories

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

    Journal Cover Stories Journal Cover Stories Here are papers authored by NERSC users that were featured on the cover of the scientific journal in which they were published. You can sort according to any of the headings below. Sort by: Default | Name | Date (low-high) | Date (high-low) | Source | Category apl 108 14 cover Gallium vacancy complexes as a cause of Shockley-Read-Hall recombination in IIInitride light emitters April 4, 2016 | Author(s): C. E. Dreyer, A. Alkauskas, J. L. Lyons, J. S.

  19. Structural and Optical Investigations of GaN-Si Interface for a Heterojunction Solar Cell

    SciTech Connect (OSTI)

    Williams, Joshua J.; Jeffries, April M.; Bertoni, Mariana I.; Williamson, Todd L.; Bowden, Stuart G.; Honsberg, Christiana B.

    2014-06-08

    In recent years the development of heterojunction silicon based solar cells has gained much attention, lea largely by the efforts of Panasonic’s HIT cell. The success of the HIT cell prompts the scientific exploration of other thin film layers, besides the industrially accepted amorphous silicon. In this paper we report upon the use of gallium nitride, grown by MBE at “low temperatures” (~200°C), on silicon wafers as one possible candidate for making a heterojunction solar cell; the first approximation of band alignments between GaN and Si; and the material quality as determined by X-ray diffraction.

  20. Semiconductor Science and Technology

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

    lighting ReSeaRch & development at Sandia national laboRatoRieS The bridge to a new way of lighting the world ssls.sandia.gov Initiates decades-long investment into compound semiconductor science and technology, eventually establishing its Center for Compound Semiconductor Science and Technology 1 9 7 7 Begins investing in gallium nitride (GaN) materials, physics, and device capabilities 1 9 9 5 Launches its Grand Challenge Laboratory Directed Research and Development Project, "A

  1. Optoelectronic simulation of GaAs solar cells with angularly selective filters

    SciTech Connect (OSTI)

    Kraus, Tobias Hhn, Oliver; Hauser, Hubert; Blsi, Benedikt

    2014-02-07

    We discuss the influence of angularly selective filters on thin film gallium arsenide solar cells. For this reason, the detailed balance model was refined to fit our needs with respect to Auger recombination, reflection, transmission, and realistic absorption. For calculating real systems, an approach was made to include optical effects of angularly selective filters into electron-hole dynamic equations implemented in PC1D, a one dimensional solar cell calculation tool. With this approach, we find a relative V{sub oc} increase of 5% for an idealized 100?nm GaAs cell, including Auger recombination.

  2. Europium-activated phosphors containing oxides of rare-earth and group-IIIB metals and method of making the same

    DOE Patents [OSTI]

    Comanzo, Holly Ann; Setlur, Anant Achyut; Srivastava, Alok Mani

    2006-04-04

    Europium-activated phosphors comprise oxides of at least a rare-earth metal selected from the group consisting of gadolinium, yttrium, lanthanum, and combinations thereof and at least a Group-IIIB metal selected from the group consisting of aluminum, gallium, indium, and combinations thereof. A method for making such phosphors comprises adding at least a halide of at least one of the selected Group-IIIB metals in a starting mixture. The method further comprises firing the starting mixture in an oxygen-containing atmosphere. The phosphors produced by such a method exhibit improved absorption in the UV wavelength range and improved quantum efficiency.

  3. Europium-activated phosphors containing oxides of rare-earth and group-IIIB metals and method of making the same

    DOE Patents [OSTI]

    Comanzo, Holly Ann; Setlur, Anant Achyut; Srivastava, Alok Mani; Manivannan, Venkatesan

    2004-07-13

    Europium-activated phosphors comprise oxides of at least a rare-earth metal selected from the group consisting of gadolinium, yttrium, lanthanum, and combinations thereof and at least a Group-IIIB metal selected from the group consisting of aluminum, gallium, indium, and combinations thereof. A method for making such phosphors comprises adding at least a halide of at least one of the selected Group-IIIB metals in a starting mixture. The method further comprises firing the starting mixture in an oxygen-containing atmosphere. The phosphors produced by such a method exhibit improved absorption in the UV wavelength range and improved quantum efficiency.

  4. Voltage clustering in redox-active ligand complexes: mitigating electronic communication through choice of metal ion

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

    Zarkesh, Ryan A.; Ichimura, Andrew S.; Monson, Todd C.; Tomson, Neil C.; Anstey, Mitchell R.

    2016-02-01

    We used the redox-active bis(imino)acenapthene (BIAN) ligand to synthesize homoleptic aluminum, chromium, and gallium complexes of the general formula (BIAN)3M. The resulting compounds were characterized using X-ray crystallography, NMR, EPR, magnetic susceptibility and cyclic voltammetry measurements and modeled using both DFT and ab initio wavefunction calculations to compare the orbital contributions of main group elements and transition metals in ligand-based redox events. Ultimately, complexes of this type have the potential to improve the energy density and electrolyte stability of grid-scale energy storage technologies, such as redox flow batteries, through thermodynamically-clustered redox events.

  5. FORMING PROTECTIVE FILMS ON METAL

    DOE Patents [OSTI]

    Gurinsky, D.H.; Kammerer, O.F.; Sadofsky, J.; Weeks, J.R.

    1958-12-16

    Methods are described of inhibiting the corrosion of ferrous metal by contact with heavy liquid metals such as bismuth and gallium at temperatures above 500 icient laborato C generally by bringing nltrogen and either the metal zirconium, hafnium, or titanium into reactlve contact with the ferrous metal to form a thin adherent layer of the nitride of the metal and thereafter maintaining a fractional percentage of the metal absorbed in the heavy liquid metal in contact with the ferrous metal container. The general purpose for uslng such high boiling liquid metals in ferrous contalners would be as heat transfer agents in liquid-metal-fueled nuclear reactors.

  6. Effects of high-temperature thermal annealing on the electronic properties of In-Ga-Zn oxide thin films

    SciTech Connect (OSTI)

    Li, Qin; Song, Zhong Xiao; Ma, Fei E-mail: liyhemail@gmail.com; Li, Yan Huai E-mail: liyhemail@gmail.com; Xu, Ke Wei

    2015-03-15

    Indium gallium zinc oxide (IGZO) thin films were deposited by radio-frequency magnetron sputtering at room-temperature. Then, thermal annealing was conducted to improve the structural ordering. X-ray diffraction and high-resolution transmission electron microscopy demonstrated that the as-deposited IGZO thin films were amorphous and crystallization occurred at 800 and 950 °C. As a result of crystallization at high temperature, the carrier concentration and the Hall mobility of IGZO thin films were sharply increased, which could be ascribed to the increased oxygen vacancies and improved structural ordering of the thin films.

  7. Micromagic Clock: Microwave Clock Based on Atoms in an Engineered Optical Lattice

    SciTech Connect (OSTI)

    Beloy, K.; Derevianko, A.; Dzuba, V. A.; Flambaum, V. V.

    2009-03-27

    We propose a new class of atomic microwave clocks based on the hyperfine transitions in the ground state of aluminum or gallium atoms trapped in optical lattices. For such elements magic wavelengths exist at which both levels of the hyperfine doublet are shifted at the same rate by the lattice laser field, canceling its effect on the clock transition. A similar mechanism for the magic wavelengths may work in microwave hyperfine transitions in other atoms which have the fine-structure multiplets in the ground state.

  8. Monolayer semiconductor nanocavity lasers with ultralow thresholds

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

    Wu, Sanfeng; Buckley, Sonia; Schaibley, John R.; Feng, Liefeng; Yan, Jiaqiang; Mandrus, David G.; Hatami, Fariba; Yao, Wang; Vučković, Jelena; Majumdar, Arka; et al

    2015-03-16

    Engineering the electromagnetic environment of a nanoscale light emitter by a photonic cavity can significantly enhance its spontaneous emission rate through cavity quantum electrodynamics in the Purcell regime. This effect can greatly reduce the lasing threshold of the emitter1–5, providing the ultimate low-threshold laser system with small footprint, low power consumption and ultrafast modulation. A state-of-the-art ultra-low threshold nanolaser has been successfully developed though embedding quantum dots into photonic crystal cavity (PhCC)6–8. However, several core challenges impede the practical applications of this architecture, including the random positions and compositional fluctuations of the dots7, extreme difficulty in current injection8, and lackmore » of compatibility with electronic circuits7,8. Here, we report a new strategy to lase, where atomically thin crystalline semiconductor, i.e., a tungsten-diselenide (WSe2) monolayer, is nondestructively and deterministically introduced as a gain medium at the surface of a pre-fabricated PhCC. A new type of continuous-wave nanolaser operating in the visible regime is achieved with an optical pumping threshold as low as 27 nW at 130 K, similar to the value achieved in quantum dot PhCC lasers7. The key to the lasing action lies in the monolayer nature of the gain medium, which confines direct-gap excitons to within 1 nm of the PhCC surface. The surface-gain geometry allows unprecedented accessibilities to multi-functionalize the gain, enabling electrically pumped operation. Our scheme is scalable and compatible with integrated photonics for on-chip optical communication technologies.« less

  9. Processing of CuInSe{sub 2}-based solar cells: Characterization of deposition processes in terms of chemical reaction analyses. Phase 2 Annual Report, 6 May 1996--5 May 1997

    SciTech Connect (OSTI)

    Anderson, T.

    1999-10-20

    This report describes research performed by the University of Florida during Phase 2 of this subcontract. First, to study CIGS, researchers adapted a contactless, nondestructive technique previously developed for measuring photogenerated excess carrier lifetimes in SOI wafers. This dual-beam optical modulation (DBOM) technique was used to investigate the differences between three alternative methods of depositing CdS (conventional chemical-bath deposition [CBD], metal-organic chemical vapor deposition [MOCVD], and sputtering). Second, a critical assessment of the Cu-In-Se thermochemical and phase diagram data using standard CALPHAD procedures is being performed. The outcome of this research will produce useful information on equilibrium vapor compositions (required annealing ambients, Sex fluxes from effusion cells), phase diagrams (conditions for melt-assisted growth), chemical potentials (driving forces for diffusion and chemical reactions), and consistent solution models (extents of solid solutions and extending phase diagrams). Third, an integrated facility to fabricate CIS PV devices was established that includes migration-enhanced epitaxy (MEE) for deposition of CIS, a rapid thermal processing furnace for absorber film formation, sputtering of ZnO, CBD or MOCVD of CdS, metallization, and pattern definition.

  10. Performance Characterization and Remedy of Experimental CuInGaSe2 Mini-Modules: Preprint

    SciTech Connect (OSTI)

    Pern, F. J.; Yan, F.; Mansfield, L.; Glynn, S.; Rekow, M.; Murion, R.

    2011-07-01

    We employed current-voltage (I-V), quantum efficiency (QE), photoluminescence (PL), electroluminescence (EL), lock-in thermography (LIT), and (electrochemical) impedance spectroscopy (ECIS) to complementarily characterize the performance and remedy for two pairs of experimental CuInGaSe2 (CIGS) mini-modules. One pair had the three scribe-lines (P1/P2/P3) done by a single pulse-programmable laser, and the other had the P2/P3 lines by mechanical scribe. Localized QE measurements for each cell strip on all four mini-modules showed non-uniform distributions that correlated well with the presence of performance-degrading strips or spots revealed by PL, EL, and LIT imaging. Performance of the all-laser-scribed mini-modules improved significantly by adding a thicker Al-doped ZnO layer and reworking the P3 line. The efficiency on one of the all-laser-scribed mini-modules increased notably from 7.80% to 8.56% after the performance-degrading spots on the side regions along the cell array were isolated by manual scribes.

  11. Heat load of a P-doped GaAs photocathode in SRF electron gun

    SciTech Connect (OSTI)

    Wang, E.; Ben-Zvi, I.; Kewisch, J.; Burrill, A.; Rao, T.; Wu, Q.; Jain, A.; Gupta, R.; Holmes, D.

    2010-05-23

    Many efforts were made over the last decades to develop a better polarized electron source for the high energy physics. Several laboratories operate DC guns with the Gallium-Arsenide photo-cathode, which yield a highly polarized electron beam. However, the beam's emittance might well be improved using a Superconducting RF electron gun, which delivers beams of higher brightness than DC guns does, because the field gradient at the cathode is higher. SRF guns with metal cathodes and CsTe cathodes have been tested successfully. To produce polarized electrons, a Gallium-Arsenide photo-cathode must be used: an experiment to do so in a superconducting RF gun is under way at BNL. Since the cathode will be normal conducting, the problem about the heat load stemming from the cathode arises. We present our measurements of the electrical resistance of GaAs at cryogenic temperatures, a prediction of the heat load and the verification by measuring the quality factor of the gun with and without cathode.

  12. Preparation of cuxinygazsen precursor films and powders by electroless deposition

    DOE Patents [OSTI]

    Bhattacharya, Raghu N.; Batchelor, Wendi Kay; Wiesner, Holm; Ramanathan, Kannan; Noufi, Rommel

    1999-01-01

    A method for electroless deposition of Cu.sub.x In.sub.y Ga.sub.z Se.sub.n (x=0-2, y=0-2, z=0-2, n=0-3) precursor films and powders onto a metallic substrate comprising: preparing an aqueous bath solution of compounds selected from the group consisting of: I) a copper compound, a selenium compound, an indium compound and gallium compound; II) a copper compound, a selenium compound and an indium compound; III) a selenium compound, and indium compound and a gallium compound; IV) a selenium compound and a indium compound; and V) a copper compound and selenium compound; each compound being present in sufficient quantity to react with each other to produce Cu.sub.x In.sub.y Ga.sub.z Se.sub.n (x=0-2, y=0-2, z=0-2, n=0-3); adjusting the pH of the aqueous bath solution to an acidic value by the addition of a dilute acid; and initiating an electroless reaction with an oxidizing counterelectrode for a sufficient time to cause a deposit of Cu.sub.x In.sub.y Ga.sub.z Se.sub.n (x=0-2, y=0-2, z=0-2, n=0-3) from the aqueous bath solution onto a metallic substrate.

  13. InGaAsN/GaAs heterojunction for multi-junction solar cells

    DOE Patents [OSTI]

    Kurtz, Steven R.; Allerman, Andrew A.; Klem, John F.; Jones, Eric D.

    2001-01-01

    An InGaAsN/GaAs semiconductor p-n heterojunction is disclosed for use in forming a 0.95-1.2 eV bandgap photodetector with application for use in high-efficiency multi-junction solar cells. The InGaAsN/GaAs p-n heterojunction is formed by epitaxially growing on a gallium arsenide (GaAs) or germanium (Ge) substrate an n-type indium gallium arsenide nitride (InGaAsN) layer having a semiconductor alloy composition In.sub.x Ga.sub.1-x As.sub.1-y N.sub.y with 070%.

  14. Numerical simulations of epitaxial growth process in MOVPE reactor as a tool for design of modern semiconductors for high power electronics

    SciTech Connect (OSTI)

    Skibinski, Jakub; Wejrzanowski, Tomasz; Caban, Piotr; Kurzydlowski, Krzysztof J.

    2014-10-06

    In the present study numerical simulations of epitaxial growth of gallium nitride in Metal Organic Vapor Phase Epitaxy reactor AIX-200/4RF-S is addressed. Epitaxial growth means crystal growth that progresses while inheriting the laminar structure and the orientation of substrate crystals. One of the technological problems is to obtain homogeneous growth rate over the main deposit area. Since there are many agents influencing reaction on crystal area such as temperature, pressure, gas flow or reactor geometry, it is difficult to design optimal process. According to the fact that it's impossible to determine experimentally the exact distribution of heat and mass transfer inside the reactor during crystal growth, modeling is the only solution to understand the process precisely. Numerical simulations allow to understand the epitaxial process by calculation of heat and mass transfer distribution during growth of gallium nitride. Including chemical reactions in numerical model allows to calculate the growth rate of the substrate and estimate the optimal process conditions for obtaining the most homogeneous product.

  15. Chemistry and Properties of Complex Intermetallics from Metallic Fluxes

    SciTech Connect (OSTI)

    Kanatzidis, Mercouri G.

    2015-03-28

    This project investigated the reaction chemistry and synthesis of new intermetallic materials with complex compositions and structures using metallic fluxes as solvents. It was found that the metallic fluxes offer several key advantages in facilitating the formation and crystal growth of new materials. The fluxes mostly explored were liquid aluminum, gallium and indium. The main purpose of this project was to exploit the potential of metallic fluxes as high temperature solvent for materials discovery in the broad class of intermetallics. This work opened new paths to compound formation. We discovered many new Si (or Ge)-based compounds with novel structures, bonding and physicochemical properties. We created new insights about the reaction chemistry that is responsible for stabilizing the new materials. We also studied the structural and compositional relationships to understand their properties. We investigated the use of Group-13 metals Al, Ga and In as solvents and have generated a wide variety of new results including several new ternary and quaternary materials with fascinating structures and properties as well as new insights as to how these systems are stabilized in the fluxes. The project focused on reactions of metals from the rare earth element family in combination with transition metals with Si and Ge. For example molten gallium has serves both as a reactive and non-reactive solvent in the preparation and crystallization of intermetallics in the system RE/M/Ga/Ge(Si). Molten indium behaves similarly in that it too is an excellent reaction medium, but it gives compounds that are different from those obtained from gallium. Some of the new phase identified in the aluminide class are complex phases and may be present in many advanced Al-matrix alloys. Such phases play a key role in determining (either beneficially or detrimentally) the mechanical properties of advanced Al-matrix alloys. This project enhanced our basic knowledge of the solid state chemistry

  16. Novel wide band gap materials for highly efficient thin film tandem solar cells

    SciTech Connect (OSTI)

    Brian E. Hardin, Stephen T. Connor, Craig H. Peters

    2012-06-11

    mixture of solution and physical vapor deposition processing, but these films lacked the p-type doping levels that are required to make decent solar cells. Over the course of the project PLANT PV was able to fabricate efficient CIGS solar cells (8.7%) but could not achieve equivalent performance using AIGS. During the nine-month grant PLANT PV set up a variety of thin film characterization tools (e.g. drive-level capacitance profiling) at the Molecular Foundry, a Department of Energy User Facility, that are now available to both industrial and academic researchers via the grant process. PLANT PV was also able to develop the back end processing of thin film solar cells at Lawrence Berkeley National Labs to achieve 8.7% efficient CIGS solar cells. This processing development will be applied to other types of thin film PV cells at the Lawrence Berkeley National Labs. While PLANT PV was able to study AIGS film growth and optoelectronic properties we concluded that AIGS produced using these methods would have a limited efficiency and would not be commercially feasible. PLANT PV did not apply for the Phase II of this grant.

  17. Fracture of solid state laser slabs

    SciTech Connect (OSTI)

    Marion, J.E.

    1986-07-01

    Fracture due to thermal stress limits the power output potential of modern, high average power slab lasers. Here the criteria for slab fracture and the nature of the surface flaws which constitute the strength-controlling defects are reviewed. Specific fracture data for gadolinium scandium gallium garnet and LHG-5 phosphate glass with different surface finishes are evaluated in the context of assigning appropriate slab operating parameters using Wiebull statistics. These examples illustrate both the danger of design using brittle components without adequate fracture testing, and the inadequacy of design methods which use a fixed safety factor, for this class of materials. Further consideration reveals that operation of slab lasers in contact with an aqueous coolant may lead to strength degradation with time. Finally, the evolution of the failure process in which a characteristic midplane crack forms is outlined, and the pertinent parameters for avoiding slab fracture are identified.

  18. Mixed-RKDG Finite Element Methods for the 2-D Hydrodynamic Model for Semiconductor Device Simulation

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

    Chen, Zhangxin; Cockburn, Bernardo; Jerome, Joseph W.; Shu, Chi-Wang

    1995-01-01

    In this paper we introduce a new method for numerically solving the equations of the hydrodynamic model for semiconductor devices in two space dimensions. The method combines a standard mixed finite element method, used to obtain directly an approximation to the electric field, with the so-called Runge-Kutta Discontinuous Galerkin (RKDG) method, originally devised for numerically solving multi-dimensional hyperbolic systems of conservation laws, which is applied here to the convective part of the equations. Numerical simulations showing the performance of the new method are displayed, and the results compared with those obtained by using Essentially Nonoscillatory (ENO) finite difference schemes. Frommore » the perspective of device modeling, these methods are robust, since they are capable of encompassing broad parameter ranges, including those for which shock formation is possible. The simulations presented here are for Gallium Arsenide at room temperature, but we have tested them much more generally with considerable success.« less

  19. Plasma treatment effect on charge carrier concentrations and surface traps in a-InGaZnO thin-film transistors

    SciTech Connect (OSTI)

    Kim, Jae-Sung; Xing Piao, Ming; Jang, Ho-Kyun; Kim, Gyu-Tae; Joo, Min-Kyu; Ahn, Seung-Eon; Choi, Yong-Hee

    2014-03-21

    Various plasma treatment effects such as oxygen (O{sub 2}), nitrogen (N{sub 2}), and argon (Ar) on amorphous indium gallium zinc oxide thin-film transistors (a-IGZO TFTs) are investigated. To study oxygen stoichiometry in a-IGZO TFTs with respect to various plasma environments, X-ray photoelectron spectroscopy was employed. The results showed that oxygen vacancies were reduced by O{sub 2} and N{sub 2} plasmas while they were increased after Ar plasma treatment. Additionally, the effects of plasma treatment on trap distribution in bulk and surface channels were explored by means of low-frequency noise analysis. Details of the mechanisms used for generating and restoring traps on the surface and bulk channel are presented.

  20. Ductile alloy and process for preparing composite superconducting wire

    DOE Patents [OSTI]

    Verhoeven, J.D.; Finnemore, D.K.; Gibson, E.D.; Ostenson, J.E.

    An alloy for the commercial production of ductile superconducting wire is prepared by melting together copper and at least 15 weight percent niobium under non-oxygen-contaminating conditions, and rapidly cooling the melt to form a ductile composite consisting of discrete, randomly distributed and oriented dendritic-shaped particles of niobium in a copper matrix. As the wire is worked, the dendritic particles are realigned parallel to the longitudinal axis and when drawn form a plurality of very fine ductile superconductors in a ductile copper matrix. The drawn wire may be tin coated and wound into magnets or the like before diffusing the tin into the wire to react with the niobium. Impurities such as aluminum or gallium may be added to improve upper critical field characteristics.

  1. Ductile alloy and process for preparing composite superconducting wire

    DOE Patents [OSTI]

    Verhoeven, John D.; Finnemore, Douglas K.; Gibson, Edwin D.; Ostenson, Jerome E.

    1983-03-29

    An alloy for the commercial production of ductile superconducting wire is prepared by melting together copper and at least 15 weight percent niobium under non-oxygen-contaminating conditions, and rapidly cooling the melt to form a ductile composite consisting of discrete, randomly distributed and orientated dendritic-shaped particles of niobium in a copper matrix. As the wire is worked, the dendritric particles are realigned parallel to the longitudinal axis and when drawn form a plurality of very fine ductile superconductors in a ductile copper matrix. The drawn wire may be tin coated and wound into magnets or the like before diffusing the tin into the wire to react with the niobium. Impurities such as aluminum or gallium may be added to improve upper critical field characteristics.

  2. Fundamental and applied studies of helium ingrowth and aging in plutonium

    SciTech Connect (OSTI)

    Stevens, M.F.; Zocco, T.; Albers, R.; Becker, J.D.; Walter, K.; Cort, B.; Paisley, D.; Nastasi, M.

    1998-12-31

    This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The purpose of this project was to develop new capabilities to assess the nucleation and growth of helium-associated defects in aged plutonium metal. This effort involved both fundamental and applied models to assist in predicting the transport and kinetics of helium in the metal lattice as well as ab initio calculations of the disposition of gallium in the fcc plutonium lattice and its resulting effects on phase stability. Experimentally this project aimed to establish experimental capabilities crucial to the prediction of helium effects in metals, such as transmission electron microscopy, thermal helium effusion, and the development of a laser-driven mini-flyer for understanding the role of helium and associated defects on shock response of plutonium surrogates.

  3. Enhanced Thermoelectric Properties of Cu2ZnSnSe4 with Ga-doping

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

    Wei, Kaya; Beauchemin, Laura; Wang, Hsin; Porter, Wallace D.; Martin, Joshua; Nolas, George S.

    2015-08-10

    Gallium doped Cu2ZnSnSe4 quaternary chalcogenides with and without excess Cu were synthesized by elemental reaction and densified using hot pressing in order to investigate their high temperature thermoelectric properties. The resistivity, , and Seebeck coefficient, S, for these materials decrease with increased Ga-doping while both mobility and effective mass increase with Ga doping. The power factor (S2/ρ) therefore increases with Ga-doping. The highest thermoelectric figure of merit (ZT = 0.39 at 700 K) was obtained for the composition that had the lowest thermal conductivity. Our results suggest an approach to achieving optimized thermoelectric properties and are part of the continuingmore » effort to explore different quaternary chalcogenide compositions and structure types, as this class of materials continues to be of interest for thermoelectrics applications.« less

  4. ION PUMP

    DOE Patents [OSTI]

    Milleron, N.

    1961-01-01

    An ion pump and pumping method are given for low vacuum pressures in which gases introduced into a pumping cavity are ionized and thereafter directed and accelerated into a quantity of liquid gettering metal where they are absorbed. In the preferred embodiment the metal is disposed as a liquid pool upon one electrode of a Phillips ion gauge type pump. Means are provided for continuously and remotely withdrawing and degassing the gettering metal. The liquid gettering metal may be heated if desired, although various combinations of gallium, indium, tin, bismuth, and lead, the preferred metals, have very low melting points. A background pressure of evaporated gettering metal may be provided by means of a resistance heated refractory metal wick protruding from the surface of the pcol of gettering metal.

  5. Picosecond x-ray strain rosette reveals direct laser excitation of coherent transverse acoustic phonons

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

    Lee, Sooheyong; Williams, G. Jackson; Campana, Maria I.; Walko, Donald A.; Landahl, Eric C.

    2016-01-11

    Using a strain-rosette, we demonstrate the existence of transverse strain using time-resolved x-ray diffraction from multiple Bragg reflections in laser-excited bulk gallium arsenide. We find that anisotropic strain is responsible for a considerable fraction of the total lattice motion at early times before thermal equilibrium is achieved. Our measurements are described by a new model where the Poisson ratio drives transverse motion, resulting in the creation of shear waves without the need for an indirect process such as mode conversion at an interface. Finally, using the same excitation geometry with the narrow-gap semiconductor indium antimonide, we detected coherent transverse acousticmore » oscillations at frequencies of several GHz.« less

  6. A High Temperature-Tolerant and Radiation-Resistant In-Core Neutron Sensor for Advanced Reactors. Final report

    SciTech Connect (OSTI)

    Cao, Lei; Miller, Don

    2015-01-23

    The objectives of this project are to develop a small and reliable gallium nitride (GaN) neutron sensor that is capable of withstanding high neutron fluence and high temperature, isolating gamma background, and operating in a wide dynamic range. The first objective will be the understanding of the fundamental materials properties and electronic response of a GaN semiconductor materials and device in an environment of high temperature and intense neutron field. To achieve such goal, an in-situ study of electronic properties of GaN device such as I-V, leakage current, and charge collection efficiency (CCE) in high temperature using an external neutron beam will be designed and implemented. We will also perform in-core irradiation of GaN up to the highest yet fast neutron fluence and an off-line performance evaluation.

  7. Solar neutrino experiments: An update

    SciTech Connect (OSTI)

    Hahn, R.L.

    1993-12-31

    The situation in solar neutrino physics has changed drastically in the past few years, so that now there are four neutrino experiments in operation, using different methods to look at different regions of the solar neutrino energy spectrum. These experiments are the radiochemical {sup 37}Cl Homestake detector, the realtime Kamiokande detector, and the different forms of radiochemical {sup 71}Ga detectors used in the GALLEX and SAGE projects. It is noteworthy that all of these experiments report a deficit of observed neutrinos relative to the predictions of standard solar models (although in the case of the gallium detectors, the statistical errors are still relatively large). This paper reviews the basic principles of operation of these neutrino detectors, reports their latest results and discusses some theoretical interpretations. The progress of three realtime neutrino detectors that are currently under construction, SuperKamiok, SNO and Borexino, is also discussed.

  8. I-III-VI.sub.2 based solar cell utilizing the structure CuInGaSe.sub.2 CdZnS/ZnO

    DOE Patents [OSTI]

    Chen, Wen S.; Stewart, John M.

    1992-01-07

    A thin film I-III-VI.sub.2 based solar cell having a first layer of copper indium gallium selenide, a second layer of cadmium zinc sulfide, a double layer of zinc oxide, and a metallization structure comprised of a layer of nickel covered by a layer of aluminum. An optional antireflective coating may be placed on said metallization structure. The cadmium zinc sulfide layer is deposited by means of an aqueous solution growth deposition process and may actually consist of two layers: a low zinc content layer and a high zinc content layer. Photovoltaic efficiencies of 12.5% at Air Mass 1.5 illumination conditions and 10.4% under AMO illumination can be achieved.

  9. LIFE CYCLE INVENTORY ANALYSIS IN THE PRODUCTION OF METALS USED IN PHOTOVOLTAICS.

    SciTech Connect (OSTI)

    FTHENAKIS,V.M.; KIM, H.C.; WANG, W.

    2007-03-30

    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.

  10. Buffer layer between a planar optical concentrator and a solar cell

    SciTech Connect (OSTI)

    Solano, Manuel E.; Barber, Greg D.; Lakhtakia, Akhlesh; Faryad, Muhammad; Monk, Peter B.; Mallouk, Thomas E.

    2015-09-15

    The effect of inserting a buffer layer between a periodically multilayered isotropic dielectric (PMLID) material acting as a planar optical concentrator and a photovoltaic solar cell was theoretically investigated. The substitution of the photovoltaic material by a cheaper dielectric material in a large area of the structure could reduce the fabrication costs without significantly reducing the efficiency of the solar cell. Both crystalline silicon (c-Si) and gallium arsenide (GaAs) were considered as the photovoltaic material. We found that the buffer layer can act as an antireflection coating at the interface of the PMLID and the photovoltaic materials, and the structure increases the spectrally averaged electron-hole pair density by 36% for c-Si and 38% for GaAs compared to the structure without buffer layer. Numerical evidence indicates that the optimal structure is robust with respect to small changes in the grating profile.

  11. High-voltage field effect transistors with wide-bandgap β-Ga{sub 2}O{sub 3} nanomembranes

    SciTech Connect (OSTI)

    Hwang, Wan Sik E-mail: djena@nd.edu; Verma, Amit; Protasenko, Vladimir; Rouvimov, Sergei; Xing, Huili; Seabaugh, Alan; Jena, Debdeep E-mail: djena@nd.edu; Peelaers, Hartwin; Van de Walle, Chris; Haensch, Wilfried; Galazka, Zbigniew; Albrecht, Martin; Fornari, Roberto

    2014-05-19

    Nanoscale semiconductor materials have been extensively investigated as the channel materials of transistors for energy-efficient low-power logic switches to enable scaling to smaller dimensions. On the opposite end of transistor applications is power electronics for which transistors capable of switching very high voltages are necessary. Miniaturization of energy-efficient power switches can enable the integration with various electronic systems and lead to substantial boosts in energy efficiency. Nanotechnology is yet to have an impact in this arena. In this work, it is demonstrated that nanomembranes of the wide-bandgap semiconductor gallium oxide can be used as channels of transistors capable of switching high voltages, and at the same time can be integrated on any platform. The findings mark a step towards using lessons learnt in nanomaterials and nanotechnology to address a challenge that yet remains untouched by the field.

  12. Performance of Cladding on MOX Fuel with Low 240Pu/239Pu Ratio

    SciTech Connect (OSTI)

    McCoy, Kevin; Blanpain, Patrick; Morris, Robert Noel

    2014-01-01

    The U.S. Department of Energy has decided to dispose of a portion of its surplus plutonium by reconstituting it into mixed oxide (MOX) fuel and irradiating it in commercial power reactors. As part of fuel qualification, four lead assemblies were manufactured and irradiated to a maximum fuel rod average burnup of 47.3 MWd/kg heavy metal. This was the world s first commercial irradiation of MOX fuel with a 240Pu/239Pu ratio less than 0.10. Five fuel rods with varying burnups and plutonium contents were selected from one of the assemblies and shipped to Oak Ridge National Laboratory for hot cell examination. This paper discusses the results of those examinations with emphasis on cladding performance. Exams relevant to the cladding included visual and eddy current exams, profilometry, microscopy, hydrogen analysis, gallium analysis, and mechanical testing. There was no discernible effect of the type of MOX fuel on the performance of the cladding.

  13. Constricted glow discharge plasma source

    DOE Patents [OSTI]

    Anders, Andre; Anders, Simone; Dickinson, Michael; Rubin, Michael; Newman, Nathan

    2000-01-01

    A constricted glow discharge chamber and method are disclosed. The polarity and geometry of the constricted glow discharge plasma source is set so that the contamination and energy of the ions discharged from the source are minimized. The several sources can be mounted in parallel and in series to provide a sustained ultra low source of ions in a plasma with contamination below practical detection limits. The source is suitable for applying films of nitrides such as gallium nitride and oxides such as tungsten oxide and for enriching other substances in material surfaces such as oxygen and water vapor, which are difficult process as plasma in any known devices and methods. The source can also be used to assist the deposition of films such as metal films by providing low-energy ions such as argon ions.

  14. VACUUM SEALING MEANS FOR LOW VACUUM PRESSURES

    DOE Patents [OSTI]

    Milleron, N.

    1962-06-12

    S>A vacuum seal is designed in which the surface tension of a thin layer of liquid metal of low vapor pressure cooperates with adjacent surfaces to preclude passages of gases across pressure differentials as low as 10/sup -8/ mm Hg. Mating contiguous surfaces composed of copper, brass, stainless steel, nickel, molybdenum, tungsten, tantalum, glass, quartz, and/or synthetic mica are disposed to provide a maximum tolerance, D, expressed by 2 gamma /P/sub 1/, where gamma is the coefflcient of the surface tension of the metal sealant selected in dynes/cm/sub 2/. Means for heating the surfaces remotely is provided where temperatures drop below about 250 deg C. A sealant consisting of an alloy of gallium, indium, and tin, among other combinations tabulated, is disposed therebetween after treating the surfaces to improve wettability, as by ultrasonic vibrations, the surfaces and sealants being selected according to the anticipated experimental conditions of use. (AEC)

  15. Voltage Regulator Chip: Power Supplies on a Chip

    SciTech Connect (OSTI)

    2010-09-01

    ADEPT Project: CPES at Virginia Tech is finding ways to save real estate on a computer's motherboard that could be used for other critical functions. Every computer processor today contains a voltage regulator that automatically maintains a constant level of electricity entering the device. These regulators contain bulky components and take up about 30% of a computer's motherboard. CPES at Virginia Tech is developing a voltage regulator that uses semiconductors made of gallium nitride on silicon (GaN-on-Si) and high-frequency soft magnetic material. These materials are integrated on a small, 3D chip that can handle the same amount of power as traditional voltage regulators at 1/10 the size and with improved efficiency. The small size also frees up to 90% of the motherboard space occupied by current voltage regulators.

  16. Efficient Switches for Solar Power Conversion: Four Quadrant GaN Switch Enabled Three Phase Grid-Tied Microinverters

    SciTech Connect (OSTI)

    2012-02-13

    Solar ADEPT Project: Transphorm is developing power switches for new types of inverters that improve the efficiency and reliability of converting energy from solar panels into useable electricity for the grid. Transistors act as fast switches and control the electrical energy that flows in an electrical circuit. Turning a transistor off opens the circuit and stops the flow of electrical current; turning it on closes the circuit and allows electrical current to flow. In this way a transistor can be used to convert DC from a solar panel into AC for use in a home. Transphorm’s transistors will enable a single semiconductor device to switch electrical currents at high-voltage in both directions—making the inverter more compact and reliable. Transphorm is using Gallium Nitride (GaN) as a semiconductor material in its transistors instead of silicon, which is used in most conventional transistors, because GaN transistors have lower losses at higher voltages and switching frequencies.

  17. Advanced Power Electronics for LED Drivers: Advanced Technologies for integrated Power Electronics

    SciTech Connect (OSTI)

    2010-09-01

    ADEPT Project: MIT is teaming with Georgia Institute of Technology, Dartmouth College, and the University of Pennsylvania (UPenn) to create more efficient power circuits for energy-efficient light-emitting diodes (LEDs) through advances in 3 related areas. First, the team is using semiconductors made of high-performing gallium nitride grown on a low-cost silicon base (GaN-on-Si). These GaN-on-Si semiconductors conduct electricity more efficiently than traditional silicon semiconductors. Second, the team is developing new magnetic materials and structures to reduce the size and increase the efficiency of an important LED power component, the inductor. This advancement is important because magnetics are the largest and most expensive part of a circuit. Finally, the team is creating an entirely new circuit design to optimize the performance of the new semiconductors and magnetic devices it is using.

  18. Light-induced hysteresis and recovery behaviors in photochemically activated solution-processed metal-oxide thin-film transistors

    SciTech Connect (OSTI)

    Jo, Jeong-Wan; Park, Sung Kyu E-mail: skpark@cau.ac.kr; Kim, Yong-Hoon E-mail: skpark@cau.ac.kr

    2014-07-28

    In this report, photo-induced hysteresis, threshold voltage (V{sub T}) shift, and recovery behaviors in photochemically activated solution-processed indium-gallium-zinc oxide (IGZO) thin-film transistors (TFTs) are investigated. It was observed that a white light illumination caused negative V{sub T} shift along with creation of clockwise hysteresis in electrical characteristics which can be attributed to photo-generated doubly ionized oxygen vacancies at the semiconductor/gate dielectric interface. More importantly, the photochemically activated IGZO TFTs showed much reduced overall V{sub T} shift compared to thermally annealed TFTs. Reduced number of donor-like interface states creation under light illumination and more facile neutralization of ionized oxygen vacancies by electron capture under positive gate potential are claimed to be the origin of the less V{sub T} shift in photochemically activated TFTs.

  19. Flip-chip light emitting diode with resonant optical microcavity

    DOE Patents [OSTI]

    Gee, James M.; Bogart, Katherine H.A.; Fischer, Arthur J.

    2005-11-29

    A flip-chip light emitting diode with enhanced efficiency. The device structure employs a microcavity structure in a flip-chip configuration. The microcavity enhances the light emission in vertical modes, which are readily extracted from the device. Most of the rest of the light is emitted into waveguided lateral modes. Flip-chip configuration is advantageous for light emitting diodes (LEDs) grown on dielectric substrates (e.g., gallium nitride LEDs grown on sapphire substrates) in general due to better thermal dissipation and lower series resistance. Flip-chip configuration is advantageous for microcavity LEDs in particular because (a) one of the reflectors is a high-reflectivity metal ohmic contact that is already part of the flip-chip configuration, and (b) current conduction is only required through a single distributed Bragg reflector. Some of the waveguided lateral modes can also be extracted with angled sidewalls used for the interdigitated contacts in the flip-chip configuration.

  20. Search for exotic short-range interactions using paramagnetic insulators

    SciTech Connect (OSTI)

    Chu, Pinghan; Weisman, E.; Liu, C. -Y.; Long, J. C.

    2015-05-26

    We describe a proposed experimental search for exotic spin-coupled interactions using a solid-state paramagnetic insulator. The experiment is sensitive to the net magnetization induced by the exotic interaction between the unpaired insulator electrons with a dense, nonmagnetic mass in close proximity. An existing experiment has been used to set limits on the electric dipole moment of the electron by probing the magnetization induced in a cryogenic gadolinium gallium garnet sample on application of a strong electric field. With suitable additions, including a movable source mass, this experiment can be used to explore “monopole-dipole” forces on polarized electrons with unique or unprecedented sensitivity. As a result, the solid-state, nonmagnetic construction, combined with the low-noise conditions and extremely sensitive magnetometry available at cryogenic temperatures could lead to a sensitivity over 10 orders of magnitude greater than exiting limits in the range below 1 mm.