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Sample records for technology atlanta ga

  1. Secretary Moniz's Keynote at the Sam Nunn Policy Forum in Atlanta, GA --

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

    As Delivered | Department of Energy Keynote at the Sam Nunn Policy Forum in Atlanta, GA -- As Delivered Secretary Moniz's Keynote at the Sam Nunn Policy Forum in Atlanta, GA -- As Delivered April 16, 2014 - 11:35am Addthis Dr. Ernest Moniz Dr. Ernest Moniz Secretary of Energy Well, thank you. Professor Bankoff, Provost Bras, I'll also acknowledge the Bank of America support of this symposium and also my monthly support of the Bank of America which is quite considerable with those credit

  2. Building Efficiency Technologies by Tomorrow's Engineers and...

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

    Heat Exchangers, AL - Advanced Renewable Energy - Emrgy Hydro - Atlanta, GA - Fox Theater - Atlanta, GA - Atlanta BeltLine - Atlanta, GA - Ford - Atlanta, GA - SawHorse - ...

  3. Remarks by Federal Blue Ribbon Commission J. David Jameson Atlanta, GA

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

    Federal Blue Ribbon Commission J. David Jameson Atlanta, GA October 18, 2011 Good Morning. I am David Jameson. I am President and CEO of the Greater Aiken, South Carolina, Chamber of Commerce. I am here today in my capacity as current Chairman of the SRS Community Reuse Organization. The SRSCRO is a non-profit regional group supporting economic diversification and job creation in a five-county in Georgia and South Carolina near the Department of Energy's Savannah River Site. We are unique among

  4. DeKalb County/Metropolitan Atlanta Alternative Fuel and Advanced Technology

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

    Vehicle Project | Department of Energy 2 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting PDF icon arravt060_ti_francis_2012_o.pdf More Documents & Publications DeKalb County/Metropolitan Atlanta Alternative Fuel and Advanced Technology Vehicle Project DeKalb County/Metropolitan Atlanta Alternative Fuel and Advanced Technology Vehicle Project Puget Sound Clean Cities Petroleum Reduction Project

  5. DeKalb County/Metropolitan Atlanta Alternative Fuel and Advanced Technology

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

    Vehicle Project | Department of Energy 1 DOE Hydrogen and Fuel Cells Program, and Vehicle Technologies Program Annual Merit Review and Peer Evaluation PDF icon arravt060_ti_francis_2011_p.pdf More Documents & Publications DeKalb County/Metropolitan Atlanta Alternative Fuel and Advanced Technology Vehicle Project DeKalb County/Metropolitan Atlanta Alternative Fuel and Advanced Technology Vehicle Project Clean Cities 2009 Petroleum Displacement Awards

  6. DeKalb County/Metropolitan Atlanta Alternative Fuel and Advanced Technology

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

    Vehicle Project | Department of Energy 0 DOE Vehicle Technologies and Hydrogen Programs Annual Merit Review and Peer Evaluation Meeting, June 7-11, 2010 -- Washington D.C. PDF icon tiarravt060_francis_2010_p.pdf More Documents & Publications DeKalb County/Metropolitan Atlanta Alternative Fuel and Advanced Technology Vehicle Project DeKalb County/Metropolitan Atlanta Alternative Fuel and Advanced Technology Vehicle Project Clean Cities Recovery Act: Vehicle & Infrastructure Deployment

  7. USD E'16 ATLANTA

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

    USD E'16 ATLANTA 2016 REGISTER NOW! 15th Annual DOE Small Business Forum & Expo MAY 23 - 25, 2016 Atlanta Marriott Marquis 265 Peachtree Center Avenue Atlanta, GA 30303 Government per diem $135.00/night (+taxes/fees) Register Now for USDOE16! smallbusinessconference.energy.gov CLICK HERE TO REGISTER

  8. EECBG Success Story: Atlanta Suburb Greases the Path to Savings...

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

    Atlanta Suburb Greases the Path to Savings with Biodiesel EECBG Success Story: Atlanta ... of the City of Savannah, GA. EECBG Success Story: In Savannah, Georgia, Even the ...

  9. Advancing Residential Retrofits in Atlanta

    SciTech Connect (OSTI)

    Jackson, Roderick K; Kim, Eyu-Jin; Roberts, Sydney; Stephenson, Robert

    2012-07-01

    This report will summarize the home energy improvements performed in the Atlanta, GA area. In total, nine homes were retrofitted with eight of the homes having predicted source energy savings of approximately 30% or greater based on simulated energy consumption.

  10. Building America Technology Solutions for New and Existing Homes: Ground

    Energy Savers [EERE]

    Source Heat Pump Research, TaC Studios Residence, Atlanta, Georigia (Fact Sheet), | Department of Energy Ground Source Heat Pump Research, TaC Studios Residence, Atlanta, Georigia (Fact Sheet), Building America Technology Solutions for New and Existing Homes: Ground Source Heat Pump Research, TaC Studios Residence, Atlanta, Georigia (Fact Sheet), This case study describes the construction of a new test home in Atlanta, GA, that demonstrates current best practices for the mixed-humid climate,

  11. 2009 National Electric Transmission Congestion Study- Atlanta Workshop

    Broader source: Energy.gov [DOE]

    On July 29, 2008, DOE hosted a regional pre-study workshop in Atlanta, GA to receive input and suggestions concerning the 2009 National Electric Transmission Congestion Study. The agenda and full...

  12. WNRC diverting to Atlanta FRC | Department of Energy

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

    PDF icon NOTICE - NARA Diversion Prgm re WNRC Transfers Routed to FRC-Atlanta, GA.pdf More Documents & Publications Denver FRC diverting to Kingsridge FRC (Dayton, OH) POINT OF CONTACT RESPONSIBILITIES FOR RECORDS MANAGEMENT Records Management POC Responsibilities

  13. Atlanta Chemical Engineering LLC | Open Energy Information

    Open Energy Info (EERE)

    Atlanta Chemical Engineering LLC Jump to: navigation, search Logo: Atlanta Chemical Engineering LLC Name: Atlanta Chemical Engineering LLC Place: Marietta, Georgia Country: United...

  14. Making Connections for Atlanta Students

    Broader source: Energy.gov [DOE]

    The Atlanta Students in Energy and Climate Forum, held in April 2013, brought together entrepreneurs, and professors to share experiences and motivations in their pursuit of environmental stewardship.

  15. Atlanta, Georgia: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    Solarity Sustainable World Capital TCE Energy Corporation Waspa Wheego Electric Cars Energy Incentives for Atlanta, Georgia City of Atlanta - Sustainable Home Initiative in...

  16. Meeting Materials: Consent-Based Siting Public Meeting in Atlanta (April

    Energy Savers [EERE]

    11, 2016) | Department of Energy Meeting Materials: Consent-Based Siting Public Meeting in Atlanta (April 11, 2016) Meeting Materials: Consent-Based Siting Public Meeting in Atlanta (April 11, 2016) The Department will host a public meeting on consent-based siting on April 11th in Atlanta at the Georgia Institute of Technology Conference Center. The meeting will include a presentation by John Kotek, Acting Assistant Secretary for Nuclear Energy at the Department of Energy; a speaker panel

  17. Atlanta TEC Meeting -- Tribal Group Summary 3-6-07

    Office of Environmental Management (EM)

    Atlanta, GA - January 31, 2007 Session Chaired by: Jay Jones (DOE, Office of Civilian Radioactive Waste Management, OCRWM) Regular Members in Attendance: Kenny Anderson (Las Vegas Paiute Tribe), Richard Arnold (Las Vegas Indian Center/Pahrump Paiute Tribe), Tony Boyd (Pueblo of Acoma), Rob Burnside (Confederated Tribes of the Umatilla Indian Reservation, CTUIR), Floyd Chaney (Mohegan Tribe), Sandra Covi (Union Pacific Railroad), Martha Crosland (DOE/Office of General Counsel, GC), Kristen Ellis

  18. DeKalb County/Metropolitan Atlanta Alternative Fuel and Advanced...

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

    60tifrancis2012o.pdf More Documents & Publications DeKalb CountyMetropolitan Atlanta Alternative Fuel and Advanced Technology Vehicle Project DeKalb CountyMetropolitan...

  19. DeKalb County/Metropolitan Atlanta Alternative Fuel and Advanced...

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

    vt060francis2010p.pdf More Documents & Publications DeKalb CountyMetropolitan Atlanta Alternative Fuel and Advanced Technology Vehicle Project DeKalb CountyMetropolitan...

  20. DeKalb County/Metropolitan Atlanta Alternative Fuel and Advanced...

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

    60tifrancis2011p.pdf More Documents & Publications DeKalb CountyMetropolitan Atlanta Alternative Fuel and Advanced Technology Vehicle Project DeKalb CountyMetropolitan...

  1. Progress toward technology transition of GaInP{sub 2}/GaAs/Ge multijunction solar cells

    SciTech Connect (OSTI)

    Keener, D.N.; Marvin, D.C.; Brinker, D.J.; Curtis, H.B.; Price, P.M.

    1997-12-31

    The objective of the joint WL/PL/NASA Multijunction Solar Cell Manufacturing Technology (ManTech) Program is to scale up high efficiency GaInP{sub 2}/GaAs/Ge multijunction solar cells to production size, quantity, and yield while limiting the production cost/Watt ($/W) to 15% over GaAs cells. Progress made by the program contractors, Spectrolab and TECSTAR, include, respectively, best cell efficiencies of 25.76% and 24.7% and establishment of 24.2% and 23.8% lot average efficiency baseline designs. The paper also presents side-by-side testing results collected by Phillips Laboratory and NASA Lewis on Phase 1 deliverable cells, which shows compliance with program objectives. Cell performance, pre- and post-radiation, and temperature coefficient results on initial production GaInP{sub 2}/GaAs/Ge solar cells will be presented.

  2. Energy Department Announces Progress, Next Steps on Improving the Reliability of the Nation’s Electric Grid with Synchrophasor Technology

    Broader source: Energy.gov [DOE]

    On March 22, 2016, as the first-ever International Synchrophasor Symposium continues in Atlanta, GA, the Department of Energy’s (DOE) Office of Electricity Delivery and Energy Reliability (OE) released a new report chronicling American efforts to deploy this technology as well as two new funding opportunities to further advance the technology.

  3. Alternative Fuels Data Center: Atlanta Airport Converts Shuttles to CNG

    Alternative Fuels and Advanced Vehicles Data Center [Office of Energy Efficiency and Renewable Energy (EERE)]

    Atlanta Airport Converts Shuttles to CNG to someone by E-mail Share Alternative Fuels Data Center: Atlanta Airport Converts Shuttles to CNG on Facebook Tweet about Alternative Fuels Data Center: Atlanta Airport Converts Shuttles to CNG on Twitter Bookmark Alternative Fuels Data Center: Atlanta Airport Converts Shuttles to CNG on Google Bookmark Alternative Fuels Data Center: Atlanta Airport Converts Shuttles to CNG on Delicious Rank Alternative Fuels Data Center: Atlanta Airport Converts

  4. Low-cost, high-efficiency solar cells utilizing GaAs-on-Si technology

    SciTech Connect (OSTI)

    Vernon, S.M. )

    1993-04-01

    This report describes work to develop technology to deposit GaAs on Si using a nucleation layer of atomic-layer-epitaxy-grown GaAs or AlAs on Si. This ensures two-dimensional nucleation and should lead to fewer defects in the final GaAs layer. As an alternative, we also developed technology for depositing GaAs on sawtooth-patterned Si. Preliminary studies showed that this material can have a very low defect density, [approximately] 1 [times] 10[sup 5] cm[sup [minus]5], as opposed to our conventionally grown GaAs on SL which has a typical defect density of over 1 [times]10[sup 7] cm[sup [minus]2]. Using these two now methods of GaAs-on-Si material growth, we made solar cells that are expected to show higher efficiencies than those of previous cells.

  5. Quaternary InGaAsSb Thermophotovoltaic Diode Technology

    SciTech Connect (OSTI)

    M Dashiell; J Beausang; H Ehsani; G Nichols; D DePoy; L Danielson; P Talamo; K Rahner; E Brown; S Burger; P Fourspring; W Topper; P Baldasaro; C Wang; R Huang; M Connors; G Turner; Z Shellenbarger; G Taylor; Jizhong Li; R Martinelli; D Donetski; S Anikeev; G Belenky; S Luryl

    2005-01-26

    Thermophotovoltaic (TPV) diodes fabricated from InGaAsSb alloys lattice-matched to GaSb substrates are grown by Metal Organic Vapor Phase Epitaxy (MOVPE). 0.53eV InGaAsSb TPV diodes utilizing front-surface spectral control filters have been tested in a vacuum cavity and a TPV thermal-to-electric conversion efficiency ({eta}{sub TPV}) and a power density (PD) of {eta}{sub TPV} = 19% and PD=0.58 W/cm{sup 2} were measured for T{sub radiator} = 950 C and T{sub diode} = 27 C. Recombination coefficients deduced from minority carrier measurements and the theory reviewed in this article predict a practical limit to the maximum achievable conversion efficiency and power density for 0.53eV InGaAsSb TPV. The limits for the above operating temperatures are projected to be {eta}{sub TPV} = 26% and PD = 0.75 W/cm{sup 2}. These limits are extended to {eta}{sub TPV} = 30% and PD = 0.85W/cm{sup 2} if the diode active region is bounded by a reflective back surface to enable photon recycling and a two-pass optical path length. The internal quantum efficiency of the InGaAsSb TPV diode is close to the theoretically predicted limits, with the exception of short wavelength absorption in GaSb contact layers. Experiments show that the open circuit voltage of the 0.53eV InGaAsSb TPV diodes is not strongly dependent on the device architectures studied in this work where both N/P and P/N double heterostructure diodes have been grown with various acceptor and donor doping levels, having GaSb and AlGaAsSb confinement, and also partial back surface reflectors. Lattice matched InGaAsSb TPV diodes were fabricated with bandgaps ranging from 0.6 to 0.5eV without significant degradation of the open circuit voltage factor, quantum efficiency, or fill factor as the composition approached the miscibility gap. The key diode performance parameter which is limiting efficiency and power density below the theoretical limits in InGaAsSb TPV devices is the open circuit voltage. The open circuit voltages of state-of-the-art 0.53eV InGaAsSb TPV diode are {approx}10% lower than the predicted semi-empirical limit to open circuit voltage for a device having absorbing substrate; the voltages are {approx}17% below that for an Auger-limited device having back surface reflector and two-pass optical design.

  6. Southface Energy Institute: Advanced Commercial Buildings Initiative |

    Energy Savers [EERE]

    Department of Energy Southface Energy Institute: Advanced Commercial Buildings Initiative Southface Energy Institute: Advanced Commercial Buildings Initiative Southface Energy Institute: Advanced Commercial Buildings Initiative Lead Performer: Southface Energy Institute - Atlanta, GA Partners: - City of Atlanta - Atlanta, GA - Georgia Institute of Technology - Atlanta, GA - Kendeda Fund - Atlanta, GA - Oak Ridge National Laboratory - Oak Ridge, TN - Acuity Brands Lighting - Atlanta, GA -

  7. Archive Reference Buildings by Climate Zone: 3A Atlanta, Georgia...

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

    Archive Reference Buildings by Climate Zone: 3A Atlanta, Georgia Archive Reference Buildings by Climate Zone: 3A Atlanta, Georgia Here you will find past versions of the reference ...

  8. Workplace Charging Challenge Partner: City of Atlanta | Department of

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

    Energy Atlanta Workplace Charging Challenge Partner: City of Atlanta Workplace Charging Challenge Partner: City of Atlanta The City of Atlanta's provision of workplace charging builds upon a larger strategy to improve transportation in the region and provide sustainable transportation options. The first component focuses on increasing the adoption of alternative transportation methods including walking, biking, public transportation, car-sharing, and alternative workplace strategies such as

  9. Clark Atlanta Universities (CAU) Energy Related Research Capabilities |

    Office of Environmental Management (EM)

    Department of Energy Clark Atlanta Universities (CAU) Energy Related Research Capabilities Clark Atlanta Universities (CAU) Energy Related Research Capabilities How energy related research has helped Clark Atlanta University. PDF icon Clark Atlanta Universities (CAU) Energy Related Research Capabilities More Documents & Publications 2008-2009 Winter Fuels Outlook Conference Ronald Reagan Building and International Trade Center HYDROGEN AND FUEL CELL EDUCATION AT CALIFORNIA STATE

  10. Autonomous Correction of Sensor Data Applied to Building Technologies...

    Office of Scientific and Technical Information (OSTI)

    DOE Contract Number: DE-AC05-00OR22725 Resource Type: Conference Resource Relation: Conference: Energy Informatics 2012, Atlanta, GA, USA, 20121006, 20121006 Research Org: Oak ...

  11. Empower Energy Technology | Open Energy Information

    Open Energy Info (EERE)

    Empower Energy Technology Jump to: navigation, search Logo: Empower Energy Technology Name: Empower Energy Technology Address: 245 N. Highland Avenue, Suite 230.162 Place: Atlanta,...

  12. City of Atlanta Video (Text Version) | Department of Energy

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

    Atlanta Video (Text Version) City of Atlanta Video (Text Version) Aaron Bastian: According to the U.S. EPA, Atlanta is one of the top ten cities in the country for green buildings. It is a city that is walk and bike friendly, and now Atlanta is second in the country for the sale of electric vehicles. Atlanta has seen tremendous adoption of plug-in electric vehicles amongst her residents, but to truly meet driver demand, chargers must be both accessible and available at major destinations such as

  13. Building America Case Study: Ground Source Heat Pump Research, TaC Studios Residence, Atlanta, Georigia (Fact Sheet), Technology Solutions for New and Existing Homes, Energy Efficiency & Renewable Energy (EERE)

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

    Ground Source Heat Pump Research, TaC Studios Residence Atlanta, Georgia PROJECT INFORMATION Construction: New Home Type: Single-family Builder: TaC Studios, tacstudios.com Size: 3,570 ft 2 Price Range: about $750,000 Date completed: 2011 Climate zone: Mixed-humid PERFORMANCE DATA HERS index: 66 Builder standard practice = 75 Case study house 3,570 ft 2 Projected annual energy cost savings: $493 Incremental cost of energy efficiency measures: $51,036 Incremental annual mortgage: $1,449 Annual

  14. Clark Atlanta Universities (CAU) Energy Related Research Capabilities...

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

    PDF icon Clark Atlanta Universities (CAU) Energy Related Research Capabilities More ... CALIFORNIA STATE UNIVERSITY, LOS ANGELES GATE Center for Automotive Fuel Cell Systems at ...

  15. Direct wafer bonding technology for large-scale InGaAs-on-insulator transistors

    SciTech Connect (OSTI)

    Kim, SangHyeon E-mail: sh-kim@kist.re.kr; Ikku, Yuki; Takenaka, Mitsuru; Takagi, Shinichi; Yokoyama, Masafumi; Nakane, Ryosho; Li, Jian; Kao, Yung-Chung

    2014-07-28

    Heterogeneous integration of III-V devices on Si wafers have been explored for realizing high device performance as well as merging electrical and photonic applications on the Si platform. Existing methodologies have unavoidable drawbacks such as inferior device quality or high cost in comparison with the current Si-based technology. In this paper, we present InGaAs-on-insulator (-OI) fabrication from an InGaAs layer grown on a Si donor wafer with a III-V buffer layer instead of growth on a InP donor wafer. This technology allows us to yield large wafer size scalability of III-V-OI layers up to the Si wafer size of 300?mm with a high film quality and low cost. The high film quality has been confirmed by Raman and photoluminescence spectra. In addition, the fabricated InGaAs-OI transistors exhibit the high electron mobility of 1700?cm{sup 2}/V s and uniform distribution of the leakage current, indicating high layer quality with low defect density.

  16. Building Efficiency Technologies by Tomorrow’s Engineers and Researchers (BETTER) Capstone

    Broader source: Energy.gov [DOE]

    Lead Performer: Georgia Institute of TechnologyAtlanta, GAPartners:  -   Alphabet Energy – Hayward, CA  -   Alabama Heat Exchangers, AL  -   Advanced Renewable Energy  -   Emrgy Hydro – Atlanta,...

  17. Meeting Materials: Consent-Based Siting Public Meeting in Atlanta...

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

    The Department will host a public meeting on consent-based siting on April 11th in Atlanta ... in turn serve as a framework for working with potential host communities in the future. ...

  18. Eleventh ARM Science Team Meeting Proceedings, Atlanta, Georgia...

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

    2001). 1 Eleventh ARM Science Team Meeting Proceedings, Atlanta, Georgia, March 19-23, 2001 From 1997 to 2001, ground-based remote sensing of thick clouds was performed at...

  19. Microsoft Word - Final TEC Notes Atlanta 07.doc

    Office of Environmental Management (EM)

    TRANSPORTATION EXTERNAL COORDINATION WORKING GROUP MEETING January 31-February 1, 2007 Atlanta, Georgia Welcome and Meeting Overview The U.S. Department of Energy (DOE), Transportation External Coordination Working Group (TEC) held its 27th meeting on January 31-February 1, 2007, in Atlanta, Georgia. One hundred thirteen participants, representing national, State, Tribal, and local government; industry; professional organizations; and other interested parties, met to address a variety of issues

  20. 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.

  1. Building America Technology Solutions for New and Existing Homes...

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

    Building America Technology Solutions for New and Existing Homes: Ground Source Heat Pump Research, TaC Studios Residence, Atlanta, Georigia (Fact Sheet), This case study describes ...

  2. Low-cost, high-efficiency solar cells utilizing GaAs-on-Si technology. Annual subcontract report, 1 August 1991--31 July 1992

    SciTech Connect (OSTI)

    Vernon, S.M.

    1993-04-01

    This report describes work to develop technology to deposit GaAs on Si using a nucleation layer of atomic-layer-epitaxy-grown GaAs or AlAs on Si. This ensures two-dimensional nucleation and should lead to fewer defects in the final GaAs layer. As an alternative, we also developed technology for depositing GaAs on sawtooth-patterned Si. Preliminary studies showed that this material can have a very low defect density, {approximately} 1 {times} 10{sup 5} cm{sup {minus}5}, as opposed to our conventionally grown GaAs on SL which has a typical defect density of over 1 {times}10{sup 7} cm{sup {minus}2}. Using these two now methods of GaAs-on-Si material growth, we made solar cells that are expected to show higher efficiencies than those of previous cells.

  3. Better Buildings Challenge, Atlanta Nears Halfway Mark in Meeting Citywide Goal of 20% Energy Savings

    Broader source: Energy.gov [DOE]

    The Energy Department yesterday recognized Atlanta for its progress and leadership in meeting a citywide goal to improve the energy performance of its buildings by 20% by 2020.

  4. Monolithically interconnected GaAs solar cells: A new interconnection technology for high voltage solar cell output

    SciTech Connect (OSTI)

    Dinetta, L.C.; Hannon, M.H.

    1995-10-01

    Photovoltaic linear concentrator arrays can benefit from high performance solar cell technologies being developed at AstroPower. Specifically, these are the integration of thin GaAs solar cell and epitaxial lateral overgrowth technologies with the application of monolithically interconnected solar cell (MISC) techniques. This MISC array has several advantages which make it ideal for space concentrator systems. These are high system voltage, reliable low cost monolithically formed interconnections, design flexibility, costs that are independent of array voltage, and low power loss from shorts, opens, and impact damage. This concentrator solar cell will incorporate the benefits of light trapping by growing the device active layers over a low-cost, simple, PECVD deposited silicon/silicon dioxide Bragg reflector. The high voltage-low current output results in minimal 12R losses while properly designing the device allows for minimal shading and resistance losses. It is possible to obtain open circuit voltages as high as 67 volts/cm of solar cell length with existing technology. The projected power density for the high performance device is 5 kW/m for an AMO efficiency of 26% at 1 5X. Concentrator solar cell arrays are necessary to meet the power requirements of specific mission platforms and can supply high voltage power for electric propulsion systems. It is anticipated that the high efficiency, GaAs monolithically interconnected linear concentrator solar cell array will enjoy widespread application for space based solar power needs. Additional applications include remote man-portable or ultra-light unmanned air vehicle (UAV) power supplies where high power per area, high radiation hardness and a high bus voltage or low bus current are important. The monolithic approach has a number of inherent advantages, including reduced cost per interconnect and increased reliability of array connections. There is also a high potential for a large number of consumer products.

  5. Registration Open for National Environmental Justice Advisory Council (NEJAC) Public Meeting, September 11-12, 2013, Atlanta, Georgia

    Broader source: Energy.gov [DOE]

    Registration Open for National Environmental Justice Advisory Council (NEJAC) Public Meeting, September 11-12, 2013, Atlanta, Georgia.

  6. Building America Case Study: Ground Source Heat Pump Research, TaC Studios Residence, Atlanta, Georigia (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2014-09-01

    As part of the NAHB Research Center Industry Partnership, Southface partnered with TaC Studios, an Atlanta based architecture firm specializing in residential and light commercial design, on the construction of a new test home in Atlanta, GA in the mixed-humid climate. This home serves as a residence and home office for the firm's owners, as well as a demonstration of their design approach to potential and current clients. Southface believes the home demonstrates current best practices for the mixed-humid climate, including a building envelope featuring advanced air sealing details and low density spray foam insulation, glazing that exceeds ENERGY STAR requirements, and a high performance heating and cooling system. Construction quality and execution was a high priority for TaC Studios and was ensured by a third party review process. Post construction testing showed that the project met stated goals for envelope performance, an air infiltration rate of 2.15 ACH50. The homeowner's wished to further validate whole house energy savings through the project's involvement with Building America and this long-term monitoring effort. As a Building America test home, this home was evaluated to detail whole house energy use, end use loads, and the efficiency and operation of the ground source heat pump and associated systems. Given that the home includes many non-typical end use loads including a home office, pool, landscape water feature, and other luxury features not accounted for in Building America modeling tools, these end uses were separately monitored to determine their impact on overall energy consumption.

  7. EECBG Success Story: Atlanta Suburb Greases the Path to Savings with

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

    Biodiesel | Department of Energy Atlanta Suburb Greases the Path to Savings with Biodiesel EECBG Success Story: Atlanta Suburb Greases the Path to Savings with Biodiesel December 7, 2011 - 3:33pm Addthis Downtown Smyrna, Georgia, a town that's poised to see big savings thanks to their investment in biodiesel. | Photo by Ken Cook Downtown Smyrna, Georgia, a town that's poised to see big savings thanks to their investment in biodiesel. | Photo by Ken Cook Downtown Smyrna, Georgia is using

  8. DOE ZERH Case Study: Heirloom Design Build, Euclid Avenue, Atlanta, GA

    SciTech Connect (OSTI)

    none,

    2015-09-01

    Case study of a DOE 2015 Housing Innovation Award winning custom home in the mixed-humid climate that got a HERS 50 without PV, with 2x6 16” on center walls with R-19 ocsf; basement with R-28 ccsf, R-5 rigid foam under slab; sealed attic with R-28 ocsf under roof deck; 22.8 SEER; 12.5 HSPF heat pump.

  9. Vehicle Technologies Office Merit Review 2015: Advanced Low-Cost SiC and GaN Wide Bandgap Inverters for Under-the-Hood Electric Vehicle Traction Drives

    Broader source: Energy.gov [DOE]

    Presentation given by APEI Inc. at 2015 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about advanced low-cost SiC and GaN wide...

  10. Vehicle Technologies Office Merit Review 2014: Advanced Low-Cost SiC and GaN Wide Bandgap Inverters for Under-the-Hood Electric Vehicle Traction Drives

    Broader source: Energy.gov [DOE]

    Presentation given by APEI Inc. at 2014 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about Advanced low-cost SIC and GaN wide...

  11. Summary of Needs and Opportunities from the 2011 Residential Energy Efficiency Stakeholders Meeting: Atlanta, Georgia -- March 16-18, 2011

    SciTech Connect (OSTI)

    Not Available

    2011-05-01

    This summary report outlines needs and issues for increasing energy efficiency of new and existing U.S homes, as identified at the U.S Department of Energy Building America program Spring 2011 stakeholder meeting in Atlanta, Georgia.

  12. NETL F 451.1/1-1, Categorical Exclusion Designation Form

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

    163 Praxair, Inc. Tonawanda, WV Georgia Institute of Technology, 505 10th Street, NW, Atlanta, GA 30332 FESCCAESD Kenneth David Lyons Improving Energy Efficiency of Air...

  13. SANDIA REPORT

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

    Matthew J. Reno, Abraham Ellis, Jeff Smith, and Roger Dugan Prepared by Sandia ... of Technology Atlanta, GA, 30332 Jeff Smith and Roger Dugan Electric Power Research ...

  14. Technology Solutions Case Study: Ground Source Heat Pump Research, TaC Studios Residence, Atlanta, Georigia

    SciTech Connect (OSTI)

    2014-09-01

    This case study describes the construction of a new test home that demonstrates current best practices for the mixed-humid climate, including a high performance ground source heat pump for heating and cooling, a building envelope featuring advanced air sealing details and low-density spray foam insulation, and glazing that exceeds ENERGY STAR requirements.

  15. Atlanta Survey

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

    Number of Fleets . . . . . . . . . . . . . . . 3,589 2,569 651 369 SIC Codes Ag.For.Fish. . . . . . . . . . . . . . . . . 140 65 31 Q Mining . . . . . . . . . . . . . . . . . ....

  16. Characterization of heavy masses of two-dimensional conduction subband in InGaAs/InAlAs MQW structures by pulsed cyclotron resonance technology

    SciTech Connect (OSTI)

    Kotera, N.; Tanaka, K. [Kyushu Inst. of Technology, Iizuka, Fukuoka (Japan); Arimoto, H.; Miura, N. [Univ. of Tokyo, Roppongi, Tokyo (Japan). Inst. of Solid State Physics; Jones, E.D. [Sandia National Labs., Albuquerque, NM (United States); Mishima, T. [Hitachi Ltd., Kokubunji, Tokyo (Japan). Central Research Lab.; Washima, M. [Hitachi Cable, Ltd., Tsukuba, Ibaraki (Japan). Advanced Research Center

    1998-05-01

    Conduction-band effective masses in a direction parallel to the quantum well plane were investigated in n-type-modulation-doped InGaAs/InAlAs multiquantum well system. Thicknesses of well and barrier were 5 and 10 nm. Three highly-doped specimens having about 1 {times} 10{sup 12} cm{sup {minus}2} per one quantum well were prepared by MBE. Double-crystal X-ray diffraction was used to check the crystal quality. Heavy electron effective masses, almost 50% bigger than the band edge mass of 0.041m{sub 0}, were measured by far-infrared and infrared cyclotron resonances under pulse high magnetic fields up to 100 T. Nonparabolicity of this subband was less than 12% by comparing the two cyclotron resonances. Observed two-dimensional subband structure was quite different from conduction-band effective mass in a direction perpendicular to the same quantum well and from GaAs/GaAlAs quantum well system.

  17. Summary of Needs and Opportunities from the 2011 Residential Energy Efficiency Stakeholders Meeting: Atlanta, Georgia -- March 16-18, 2011

    Energy Savers [EERE]

    Needs and Opportunities from the 2011 Residential Energy Efficiency Stakeholders Meeting Atlanta, Georgia - March 16-18, 2011 May 2011 ii NOTICE This report was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information,

  18. Making it pay in Athens, GA

    SciTech Connect (OSTI)

    Malloy, M.G.

    1997-04-01

    The materials recovery facility (MRF) in Athens, GA, is a well-fed recycling facility. But, if the local government has its way, it will be even better fed in the near future. The Athens-Clarke County (ACC) regional municipality in which the facility resides has a put-or-pay contract with the plant`s owner/operator, under which the more it feeds the MRF, the more money it receives in return, through the sale of recycled end products. The ACC Solid Waste Department uses a volume-based waste collection system that encourages residents to recycle--the more they recycle, the less trash they have to put out, and the less they pay each month. The Athens facility, which will be a featured site tour at next month`s WasteExpo `97 in nearby Atlanta, had its ground-breaking two years ago, in April 1995. ACC is responsible for delivering material--or seeing that recyclables are delivered--to the MRF, which is owned and operated by Resource Recovery Systems (RRS, Centerbrook, Conn.). Over the past year, ACC has stepped up various incentives for businesses to recycle and send their recyclables to the facility, including instituting pilot programs for commercial interests that offer them versions of volume-based collection similar to that done by residents.

  19. Technolog

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

    Research in Science and Technolog y Sandia pushes frontiers of knowledge to meet the nation's needs, today and tomorrow Sandia National Laboratories' fundamental science and technology research leads to greater understanding of how and why things work and is intrinsic to technological advances. Basic research that challenges scientific assumptions enables the nation to push scientific boundaries. Innovations and breakthroughs produced at Sandia allow it to tackle critical issues, from

  20. Fuel Cell Technologies Office Newsletter: July 2015 | Department of Energy

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

    5 Fuel Cell Technologies Office Newsletter: July 2015 The July 2015 issue of the Fuel Cell Technologies Office (FCTO) newsletter includes stories in these categories: In the News Webinars and Workshops Studies, Reports, and Publications National Laboratory and Principal Investigator Achievements In the News Clean Energy Manufacturing Initiative Southeast Regional Summit Held July 9 in Atlanta The Energy Department hosted the Clean Energy Manufacturing Initiative (CEMI) Southeast Regional Summit

  1. Urban airshed modeling of air quality impacts of alternative transportation fuel use in Los Angeles and Atlanta

    SciTech Connect (OSTI)

    NONE

    1997-12-01

    The main objective of NREL in supporting this study is to determine the relative air quality impact of the use of compressed natural gas (CNG) as an alternative transportation fuel when compared to low Reid vapor pressure (RVP) gasoline and reformulated gasoline (RFG). A table lists the criteria, air toxic, and greenhouse gas pollutants for which emissions were estimated for the alternative fuel scenarios. Air quality impacts were then estimated by performing photochemical modeling of the alternative fuel scenarios using the Urban Airshed Model Version 6.21 and the Carbon Bond Mechanism Version IV (CBM-IV) (Geary et al., 1988) Using this model, the authors examined the formation and transport of ozone under alternative fuel strategies for motor vehicle transportation sources for the year 2007. Photochemical modeling was performed for modeling domains in Los Angeles, California, and Atlanta, Georgia.

  2. DOE Zero Energy Ready Home Case Study: Heirloom Design Build...

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

    Heirloom Design Build, Euclid Avenue, Atlanta, GA DOE Zero Energy Ready Home Case Study: Heirloom Design Build, Euclid Avenue, Atlanta, GA Case study of a DOE 2015 Housing ...

  3. GaN: Defect and Device Issues

    SciTech Connect (OSTI)

    Pearton, S.J.; Ren, F.; Shul, R.J.; Zolper, J.C.

    1998-11-09

    The role of extended and point defects, and key impurities such as C, O and H, on the electrical and optical properties of GaN is reviewed. Recent progress in the development of high reliability contacts, thermal processing, dry and wet etching techniques, implantation doping and isolation and gate insulator technology is detailed. Finally, the performance of GaN-based electronic and photonic devices such as field effect transistors, UV detectors, laser diodes and light-emitting diodes is covered, along with the influence of process-induced or grown-in defects and impurities on the device physics.

  4. Lateral and Vertical Transistors Using the AlGaN/GaN Heterostructure

    SciTech Connect (OSTI)

    Chowdhury, S; Mishra, UK

    2013-10-01

    Power conversion losses are endemic in all areas of electricity consumption, including motion control, lighting, air conditioning, and information technology. Si, the workhorse of the industry, has reached its material limits. Increasingly, the lateral AlGaN/GaN HEMT based on gallium nitride (GaN-on-Si) is becoming the device of choice for medium power electronics as it enables high-power conversion efficiency and reduced form factor at attractive pricing for wide market penetration. The reduced form factor enabled by high-efficiency operation at high frequency further enables significant system price reduction because of savings in bulky extensive passive elements and heat sink costs. The high-power market, however, still remains unaddressed by lateral GaN devices. The current and voltage demand for high power conversion application makes the chip area in a lateral topology so large that it becomes more difficult to manufacture. Vertical GaN devices would play a big role alongside of silicon carbide (SiC) to address the high power conversion needs. In this paper, the development, performance, and status of lateral and vertical GaN devices are discussed.

  5. Development & Industrialization of InGaN/GaN LEDs on Patterned Sapphire Substrates for Low Cost Emitter Architecture

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

    Flemish, Lumileds joe.flemish@philips.com Development & Industrialization of InGaN/GaN LEDs on Patterned Sapphire Substrates for Low Cost Emitter Architecture 2015 Building Technologies Office Peer Review 2 Project Summary Timeline: Start date: August 1, 2013 Planned end date: July 31, 2015 Key Milestones: 1. Repeatable demonstration of PSS emitter performance within 1.5% of the TFFC counterpart; - met January 2014 2. Demonstration of PSS emitter performance exceeding TFFC counterpart by 2%:

  6. Ultra High p-doping Material Research for GaN Based Light Emitters

    SciTech Connect (OSTI)

    Vladimir Dmitriev

    2007-06-30

    The main goal of the Project is to investigate doping mechanisms in p-type GaN and AlGaN and controllably fabricate ultra high doped p-GaN materials and epitaxial structures. Highly doped p-type GaN-based materials with low electrical resistivity and abrupt doping profiles are of great importance for efficient light emitters for solid state lighting (SSL) applications. Cost-effective hydride vapor phase epitaxial (HVPE) technology was proposed to investigate and develop p-GaN materials for SSL. High p-type doping is required to improve (i) carrier injection efficiency in light emitting p-n junctions that will result in increasing of light emitting efficiency, (ii) current spreading in light emitting structures that will improve external quantum efficiency, and (iii) parameters of Ohmic contacts to reduce operating voltage and tolerate higher forward currents needed for the high output power operation of light emitters. Highly doped p-type GaN layers and AlGaN/GaN heterostructures with low electrical resistivity will lead to novel device and contact metallization designs for high-power high efficiency GaN-based light emitters. Overall, highly doped p-GaN is a key element to develop light emitting devices for the DOE SSL program. The project was focused on material research for highly doped p-type GaN materials and device structures for applications in high performance light emitters for general illumination P-GaN and p-AlGaN layers and multi-layer structures were grown by HVPE and investigated in terms of surface morphology and structure, doping concentrations and profiles, optical, electrical, and structural properties. Tasks of the project were successfully accomplished. Highly doped GaN materials with p-type conductivity were fabricated. As-grown GaN layers had concentration N{sub a}-N{sub d} as high as 3 x 10{sup 19} cm{sup -3}. Mechanisms of doping were investigated and results of material studies were reported at several International conferences providing better understanding of p-type GaN formation for Solid State Lighting community. Grown p-type GaN layers were used as substrates for blue and green InGaN-based LEDs made by HVPE technology at TDI. These results proved proposed technical approach and facilitate fabrication of highly conductive p-GaN materials by low-cost HVPE technology for solid state lighting applications. TDI has started the commercialization of p-GaN epitaxial materials.

  7. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    IL (United States) Atlanta Regional Office, Atlanta, GA (United States) Atmospheric System Research Bartlesville Project Office, OK (United States) Battelle Memorial...

  8. Funds Awarded to Historically Black Colleges and Universities...

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

    ... Clark Atlanta University (Atlanta, Ga.) - Engineering Accessible Adsorption Sites in Metal Organic Frameworks for CO2 Capture. Metal organic frameworks (MOFs) are a newer class of ...

  9. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Photon Source, Argonne, IL (United States) Atlanta Regional Office, Atlanta, GA (United States) Atmospheric System Research Bartlesville Project Office, OK (United...

  10. Investigation of the GaN-on-GaAs interface for vertical power device applications

    SciTech Connect (OSTI)

    Mreke, Janina Uren, Michael J.; Kuball, Martin; Novikov, Sergei V.; Foxon, C. Thomas; Hosseini Vajargah, Shahrzad; Wallis, David J.; Humphreys, Colin J.; Haigh, Sarah J.; Al-Khalidi, Abdullah; Wasige, Edward; Thayne, Iain

    2014-07-07

    GaN layers were grown onto (111) GaAs by molecular beam epitaxy. Minimal band offset between the conduction bands for GaN and GaAs materials has been suggested in the literature raising the possibility of using GaN-on-GaAs for vertical power device applications. I-V and C-V measurements of the GaN/GaAs heterostructures however yielded a rectifying junction, even when both sides of the junction were heavily doped with an n-type dopant. Transmission electron microscopy analysis further confirmed the challenge in creating a GaN/GaAs Ohmic interface by showing a large density of dislocations in the GaN layer and suggesting roughening of the GaN/GaAs interface due to etching of the GaAs by the nitrogen plasma, diffusion of nitrogen or melting of Ga into the GaAs substrate.

  11. TJ Solar Cell (GaInP/GaAs/Ge Ultrahigh-Efficiency Solar Cells

    SciTech Connect (OSTI)

    Friedman, Daniel

    2002-04-17

    This talk will discuss recent developments in III-V multijunction photovoltaic technology which have led to the highest-efficiency solar cells ever demonstrated. The relationship between the materials science of III-V semiconductors and the achievement of record solar cell efficiencies will be emphasized. For instance, epitaxially-grown GAInP has been found to form a spontaneously-ordered GaP/InP (111) superlattice. This ordering affects the band gap of the material, which in turn affects the design of solar cells which incorporate GaInP. For the next generation of ultrahigh-efficiency III-V solar cells, we need a new semiconductor which is lattice-matched to GaAs, has a band gap of 1 eV, and has long minority-carrier diffusion lengths. Out of a number of candidate materials, the recently-discovered alloy GaInNAs appears to have the greatest promise. This material satisfies the first two criteria, but has to date shown very low diffusion lengths, a problem which is our current focus in the development of these next-generation cells.

  12. GA SNC Solar | Open Energy Information

    Open Energy Info (EERE)

    GA-SNC Solar Place: Nevada Sector: Solar Product: Nevada-based PV project developer and joint venture of GA-Solar North America and Sierra Nevada Corp. References: GA-SNC...

  13. Low Cost Production of InGaN for Next-Generation Photovoltaic Devices

    SciTech Connect (OSTI)

    Nick M. Sbrockey, Shangzhu Sun, Gary S. Tompa,

    2012-07-09

    The goal of this project is to develop a low-cost and low-energy technology for production of photovoltaic devices based on InGaN materials. This project builds on the ongoing development by Structured Materials Industries (SMI), of novel thin film deposition technology for Group III-Nitride materials, which is capable of depositing Group-III nitride materials at significantly lower costs and significantly lower energy usage compared to conventional deposition techniques. During this project, SMI demonstrated deposition of GaN and InGaN films using metalorganic sources, and demonstrated compatibility of the process with standard substrate materials and hardware components.

  14. GaInNAs laser gain

    SciTech Connect (OSTI)

    CHOW,WENG W.; JONES,ERIC D.; MODINE,NORMAND A.; KURTZ,STEVEN R.; ALLERMAN,ANDREW A.

    2000-05-23

    The optical gain spectra for GaInNAs/GaAs quantum wells are computed using a microscopic laser theory. From these spectra, the peak gain and carrier radiative decay rate as functions of carrier density are determined. These dependences allow the study of the lasing threshold current density of GaInNAs/GaAs quantum well structures.

  15. General Atomics (GA) | Princeton Plasma Physics Lab

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

    General Atomics (GA) Subscribe to RSS - General Atomics (GA) General Atomics Image: General Atomics (GA) The Scorpion's Strategy: "Catch and Subdue" Read more about The Scorpion's Strategy: "Catch and Subdue" Frozen Bullets Tame Unruly Edge Plasmas in Fusion Experiment Read more about Frozen Bullets Tame Unruly Edge Plasmas in Fusion Experiment General Atomics (GA) Fusion News: A New Spin on Understanding Plasma Confinement Read more about General Atomics (GA) Fusion News: A

  16. Second annual clean coal technology conference: Proceedings. Volume 1

    SciTech Connect (OSTI)

    Not Available

    1993-09-09

    The Second Annual Clean Coal Technology Conference was held at Atlanta, Georgia, September 7--9, 1993. The Conference, cosponsored by the US Department of Energy (USDOE) and the Southern States Energy Board (SSEB), seeks to examine the status and role of the Clean Coal Technology Demonstration Program (CCTDP) and its projects. The Program is reviewed within the larger context of environmental needs, sustained economic growth, world markets, user performance requirements and supplier commercialization activities. This will be accomplished through in-depth review and discussion of factors affecting domestic and international markets for clean coal technology, the environmental considerations in commercial deployment, the current status of projects, and the timing and effectiveness of transfer of data from these projects to potential users, suppliers, financing entities, regulators, the interested environmental community and the public. Individual papers have been entered separately.

  17. GaAs, AlGaAs and InGaP Tunnel Junctions for Multi-Junction Solar Cells Under Concentration: Resistance Study

    SciTech Connect (OSTI)

    Wheeldon, Jeffrey F.; Valdivia, Christopher E.; Walker, Alex; Kolhatkar, Gitanja; Hall, Trevor J.; Hinzer, Karin; Masson, Denis; Riel, Bruno; Fafard, Simon; Jaouad, Abdelatif; Turala, Artur; Ares, Richard; Aimez, Vincent

    2010-10-14

    The following four TJ designs, AlGaAs/AlGaAs, GaAs/GaAs, AlGaAs/InGaP and AlGaAs/GaAs are studied to determine minimum doping concentration to achieve a resistance of <10{sup -4} {omega}{center_dot}cm{sup 2} and a peak tunneling current suitable for MJ solar cells up to 1500-suns concentration (operating current of 21 A/cm{sup 2}). Experimentally calibrated numerical models are used to determine how the resistance changes as a function of doping concentration. The AlGaAs/GaAs TJ design is determined to require the least doping concentration to achieve the specified resistance and peak tunneling current, followed by the GaAs/GaAs, and AlGaAs/AlGaAs TJ designs. The AlGaAs/InGaP TJ design can only achieve resistances >5x10{sup -4} {omega}cm{sup 2}.

  18. Upcoming Clean Energy Manufacturing Initiative (CEMI) Southeast Regional

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

    Summit on July 9 in Atlanta, GA | Department of Energy Upcoming Clean Energy Manufacturing Initiative (CEMI) Southeast Regional Summit on July 9 in Atlanta, GA Upcoming Clean Energy Manufacturing Initiative (CEMI) Southeast Regional Summit on July 9 in Atlanta, GA June 25, 2015 - 8:19am Addthis On July 9, the U.S. Department of Energy will be holding the Clean Energy Manufacturing Initiative (CEMI) Southeast Regional Summit at the Renaissance Atlanta Midtown Hotel in Atlanta, Georgia. The

  19. Vehicle Technologies Office Merit Review 2015: 88 Kilowatt Automotive...

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

    Technologies Office Merit Review 2015: Advanced Low-Cost SiC and GaN Wide Bandgap Inverters for Under-the-Hood Electric Vehicle Traction Drives Vehicle Technologies Office...

  20. Intense terahertz emission from molecular beam epitaxy-grown GaAs/GaSb(001)

    SciTech Connect (OSTI)

    Sadia, Cyril P.; Laganapan, Aleena Maria; Agatha Tumanguil, Mae; Estacio, Elmer; Somintac, Armando; Salvador, Arnel; Que, Christopher T.; Yamamoto, Kohji; Tani, Masahiko

    2012-12-15

    Intense terahertz (THz) electromagnetic wave emission was observed in undoped GaAs thin films deposited on (100) n-GaSb substrates via molecular beam epitaxy. GaAs/n-GaSb heterostructures were found to be viable THz sources having signal amplitude 75% that of bulk p-InAs. The GaAs films were grown by interruption method during the growth initiation and using various metamorphic buffer layers. Reciprocal space maps revealed that the GaAs epilayers are tensile relaxed. Defects at the i-GaAs/n-GaSb interface were confirmed by scanning electron microscope images. Band calculations were performed to infer the depletion region and electric field at the i-GaAs/n-GaSb and the air-GaAs interfaces. However, the resulting band calculations were found to be insufficient to explain the THz emission. The enhanced THz emission is currently attributed to a piezoelectric field induced by incoherent strain and defects.

  1. New GaInP/GaAs/GaInAs, Triple-Bandgap, Tandem Solar Cell for High-Efficiency Terrestrial Concentrator Systems

    SciTech Connect (OSTI)

    Kurtz, S.; Wanlass, M.; Kramer, C.; Young, M.; Geisz, J.; Ward, S.; Duda, A.; Moriarty, T.; Carapella, J.; Ahrenkiel, P.; Emery. K.; Jones, K.; Romero, M.; Kibbler, A.; Olson, J.; Friedman, D.; McMahon, W.; Ptak, A.

    2005-11-01

    GaInP/GaAs/GaInAs three-junction cells are grown in an inverted configuration on GaAs, allowing high quality growth of the lattice matched GaInP and GaAs layers before a grade is used for the 1-eV GaInAs layer. Using this approach an efficiency of 37.9% was demonstrated.

  2. InGaAsN/GaAs heterojunction for multi-junction solar cells

    DOE Patents [OSTI]

    Kurtz, Steven R. (Albuquerque, NM); Allerman, Andrew A. (Albuquerque, NM); Klem, John F. (Albuquerque, NM); Jones, Eric D. (Edgewood, NM)

    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 0GaAs layer, with the InGaAsN and GaAs layers being lattice-matched to the substrate. The InGaAsN/GaAs p-n heterojunction can be epitaxially grown by either molecular beam epitaxy (MBE) or metalorganic chemical vapor deposition (MOCVD). The InGaAsN/GaAs p-n heterojunction provides a high open-circuit voltage of up to 0.62 volts and an internal quantum efficiency of >70%.

  3. Graphene induced remote surface scattering in graphene/AlGaN/GaN heterostructures

    SciTech Connect (OSTI)

    Liu, Xiwen; Li, Dan; Wang, Bobo; Liu, Bin; Chen, Famin; Jin, Guangri; Lu, Yanwu

    2014-10-20

    The mobilities of single-layer graphene combined with AlGaN/GaN heterostructures on two-dimensional electron gases in graphene/AlGaN/GaN double heterojunction are calculated. The impact of electron density in single-layer graphene is also studied. Remote surface roughness (RSR) and remote interfacial charge (RIC) scatterings are introduced into this heterostructure. The mobilities limited by RSR and RIC are an order of magnitude higher than that of interface roughness and misfit dislocation. This study contributes to designing structures for generation of higher electron mobility in graphene/AlGaN/GaN double heterojunction.

  4. Magnetism and transport properties of epitaxial Fe-Ga thin films on GaAs(001)

    SciTech Connect (OSTI)

    Duong Anh Tuan; Shin, Yooleemi; Cho, Sunglae; Dang Duc Dung; Vo Thanh Son

    2012-04-01

    Epitaxial Fe-Ga thin films in disordered bcc {alpha}-Fe crystal structure (A2) have been grown on GaAs(001) by molecular beam epitaxy. The saturated magnetization (M{sub S}) decreased from 1371 to 1105 kA/m with increasing Ga concentration from 10.5 to 24.3 % at room temperature. The lattice parameter increased with the increase in Ga content because of the larger atomic radius of Ga atom than that of Fe. The increase in carrier density with Ga content caused in lower resistivity.

  5. Georgia and Arkansas Residential Energy Code Field Studies | Department of

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

    Energy Georgia and Arkansas Residential Energy Code Field Studies Georgia and Arkansas Residential Energy Code Field Studies Lead Performer: Southeast Energy Efficiency Alliance - Atlanta, GA Partners: - Advanced Energy - Raleigh, NC - Arkansas Economic Development Commission, Energy Office - Little Rock, AR - Georgia Department of Community Affairs - Atlanta, GA - Georgia Environmental Finance Authority - Atlanta, GA - Southface - Atlanta, GA DOE Total Funding: $1,399,999 Cost Share:

  6. Implementing Equipment Based Obligations Presentation

    National Nuclear Security Administration (NNSA)

    Implementation Workshop January 13, 2 Obligations Accounting Implementation Workshop January 13, 2004 004 Crowne Crowne Plaza Plaza Ravinia Ravinia Atlanta, GA Atlanta, GA page page 1 1 Implementation of Equipment Based Obligations Mark Laidlow Dominion January 13, 2004 Obligations Accounting Implementation Workshop January 13, 2 Obligations Accounting Implementation Workshop January 13, 2004 004 Crowne Crowne Plaza Plaza Ravinia Ravinia Atlanta, GA Atlanta, GA page page 2 2 Background

  7. Band Structure of Strain-Balanced GaAsBi/GaAsN Super-lattices on GaAs

    SciTech Connect (OSTI)

    Hwang, J.; Phillips, J. D.

    2011-05-31

    GaAs alloys with dilute content of Bi and N provide a large reduction in band-gap energy with increasing alloy composition. GaAsBi/GaAsN heterojunctions have a type-II band alignment, where superlattices based on these materials offer a wide range for designing effective band-gap energy by varying superlattice period and alloy composition. The miniband structure and effective band gap for strain-balanced GaAsBi/GaAsN superlattices with effective lattice match to GaAs are calculated for alloy compositions up to 5% Bi and N using the kp method. The effective band gap for these superlattices is found to vary between 0.89 and 1.32 eV for period thickness ranging from 10 to 100 . The joint density of states and optical absorption of a 40/40 GaAs0.96Bi0.04/GaAs0.98N0.02 superlattice are reported demonstrating a ground-state transition at 1.005 eV and first excited transition at 1.074 eV. The joint density of states is similar in magnitude to GaAs, while the optical absorption is approximately one order of magnitude lower due to the spatially indirect optical transition in the type-II structure. The GaAsBi/GaAsN system may provide a new material system with lattice match to GaAs in a spectral range of high importance for optoelectronic devices including solar cells, photodetectors, and light emitters.

  8. GaN Initiative for Grid Applications (GIGA)

    SciTech Connect (OSTI)

    Turner, George

    2015-07-03

    For nearly 4 years, MIT Lincoln Laboratory (MIT/LL) led a very successful, DoE-funded team effort to develop GaN-on-Si materials and devices, targeting high-voltage (>1 kV), high-power, cost-effective electronics for grid applications. This effort, called the GaN Initiative for Grid Applications (GIGA) program, was initially made up of MIT/LL, the MIT campus group of Prof. Tomas Palacios (MIT), and the industrial partner M/A Com Technology Solutions (MTS). Later in the program a 4th team member was added (IQE MA) to provide commercial-scale GaN-on-Si epitaxial materials. A basic premise of the GIGA program was that power electronics, for ubiquitous utilization -even for grid applications - should be closer in cost structure to more conventional Si-based power electronics. For a number of reasons, more established GaN-on-SiC or even SiC-based power electronics are not likely to reach theses cost structures, even in higher manufacturing volumes. An additional premise of the GIGA program was that the technical focus would be on materials and devices suitable for operating at voltages > 1 kV, even though there is also significant commercial interest in developing lower voltage (< 1 kV), cost effective GaN-on-Si devices for higher volume applications, like consumer products. Remarkable technical progress was made during the course of this program. Advances in materials included the growth of high-quality, crack-free epitaxial GaN layers on large-diameter Si substrates with thicknesses up to ~5 ?m, overcoming significant challenges in lattice mismatch and thermal expansion differences between Si and GaN in the actual epitaxial growth process. Such thick epilayers are crucial for high voltage operation of lateral geometry devices such as Schottky barrier (SB) diodes and high electron mobility transistors (HEMTs). New Normally-Off device architectures were demonstrated for safe operation of power electronics circuits. The trade-offs between lateral and vertical devices were explored, with the conclusion that lateral devices are superior for fundamental thermal reasons, as well as for the demonstration of future generations of monolithic power circuits. As part of the materials and device investigations breakdown mechanisms in GaN-on-Si structures were fully characterized and effective electric field engineering was recognized as critical for achieving even higher voltage operation. Improved device contact technology was demonstrated, including the first gold-free metallizations (to enable processing in CMOS foundries) while maintaining low specific contact resistance needed for high-power operation and 5-order-of magnitude improvement in device leakage currents (essential for high power operation). In addition, initial GaN-on-Si epitaxial growth was performed on 8/200 mm Si starting substrates.

  9. AlGaAsSb/GaSb Distributed Bragg Reflectors Grown by Organometallic Vapor Phase Epitaxy

    SciTech Connect (OSTI)

    C.A. Wang; C.J. Vineis; D.R. Calawa

    2002-02-13

    The first AlGaAsSb/GaSb quarter-wave distributed Bragg reflectors grown by metallic vapor phase epitaxy are reported. The peak reflectance is 96% for a 10-period structure.

  10. US SoAtl GA Site Consumption

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

    GA Site Consumption million Btu $0 $500 $1,000 $1,500 $2,000 $2,500 US SoAtl GA Expenditures dollars ALL ENERGY average per household (excl. transportation) 0 4,000 8,000 12,000 16,000 US SoAtl GA Site Consumption kilowatthours $0 $300 $600 $900 $1,200 $1,500 $1,800 US SoAtl GA Expenditures dollars ELECTRICITY ONLY average per household * Site energy consumption (89.5 million Btu) and energy expenditures per household ($2,067) in Georgia are similar to the U.S. household averages. * Per

  11. Influence of Barrier Design on Current Collapse in High Voltage AlGaN/GaN

    Office of Scientific and Technical Information (OSTI)

    HEMTs. (Conference) | SciTech Connect Influence of Barrier Design on Current Collapse in High Voltage AlGaN/GaN HEMTs. Citation Details In-Document Search Title: Influence of Barrier Design on Current Collapse in High Voltage AlGaN/GaN HEMTs. Abstract not provided. Authors: Biedermann, Laura Butler ; Kaplar, Robert James ; Marinella, Matthew ; Zavadil, Kevin Robert ; Atcitty, Stanley ; Sun, Min ; Palacios, Tomas Publication Date: 2012-10-01 OSTI Identifier: 1111316 Report Number(s):

  12. Influence of Barrier Design on Current Collapse in High Voltage AlGaN/GaN

    Office of Scientific and Technical Information (OSTI)

    HEMTs. (Conference) | SciTech Connect Conference: Influence of Barrier Design on Current Collapse in High Voltage AlGaN/GaN HEMTs. Citation Details In-Document Search Title: Influence of Barrier Design on Current Collapse in High Voltage AlGaN/GaN HEMTs. Abstract not provided. Authors: DasGupta, Sandeepan ; Biedermann, Laura Butler ; Kaplar, Robert ; Marinella, Matthew ; Zavadil, Kevin Robert ; Atcitty, Stanley ; Sun, Min ; Palacios, Tomas Publication Date: 2013-02-01 OSTI Identifier:

  13. GaInP/GaAs/GaInAs Monolithic Tandem Cells for High-Performance Solar Concentrators

    SciTech Connect (OSTI)

    Wanlass, M. W.; Ahrenkiel, S. P.; Albin, D. S.; Carapella, J. J.; Duda, A.; Emery, K.; Geisz, J. F.; Jones, K.; Kurtz, S.; Moriarty, T.; Romero, M. J.

    2005-08-01

    We present a new approach for ultra-high-performance tandem solar cells that involves inverted epitaxial growth and ultra-thin device processing. The additional degree of freedom afforded by the inverted design allows the monolithic integration of high-, and medium-bandgap, lattice-matched (LM) subcell materials with lower-bandgap, lattice-mismatched (LMM) materials in a tandem structure through the use of transparent compositionally graded layers. The current work concerns an inverted, series-connected, triple-bandgap, GaInP (LM, 1.87 eV)/GaAs (LM, 1.42 eV)/GaInAs (LMM, {approx}1 eV) device structure grown on a GaAs substrate. Ultra-thin tandem devices are fabricated by mounting the epiwafers to pre-metallized Si wafer handles and selectively removing the parent GaAs substrate. The resulting handle-mounted, ultra-thin tandem cells have a number of important advantages, including improved performance and potential reclamation/reuse of the parent substrate for epitaxial growth. Additionally, realistic performance modeling calculations suggest that terrestrial concentrator efficiencies in the range of 40-45% are possible with this new tandem cell approach. A laboratory-scale (0.24 cm2), prototype GaInP/GaAs/GaInAs tandem cell with a terrestrial concentrator efficiency of 37.9% at a low concentration ratio (10.1 suns) is described, which surpasses the previous world efficiency record of 37.3%.

  14. Ground-state energy trends in single and multilayered coupled InAs/GaAs quantum dots capped with InGaAs layers: Effects of InGaAs layer thickness and annealing temperature

    SciTech Connect (OSTI)

    Shah, S.; Ghosh, K.; Jejurikar, S.; Mishra, A.; Chakrabarti, S.

    2013-08-01

    Graphical abstract: - Highlights: Investigation of ground state energy in single and multi-layered InAs/GaAs QD. Strain reducing layer (InGaAs) prevents the formation of non-radiative. Strain reducing layer (InGaAs) is responsible for high activation energy. Significant deviation from the Varshni model, E(T) = E ? ?T{sup 2}/T + ?. - Abstract: Vertically coupled, multilayered InAs/GaAs quantum dots (QDs) covered with thin InGaAs strain-reducing layers (SRLs) are in demand for various technological applications. We investigated low temperature photoluminescence of single and multilayered structures in which the SRL thickness was varied. The SRL layer was responsible for high activation energies. Deviation of experimental data from the Varshni (1967) model, E(T) = E ? ? T{sup 2}/T + ?, suggests that the InAs-layered QDs have properties different from those in bulk material. Anomalous ground-state peak linewidths (FWHM), especially for annealed multilayer structures, were observed. A ground-state peak blue-shift with a broadened linewidth was also observed. Loss of intensity was detected in samples annealed at 800 C. Presence of SRLs prevents formation of non-radiative centers under high temperature annealing. The results indicate the potential importance of such structures in optoelectronic applications.

  15. Metal-interconnection-free integration of InGaN/GaN light emitting diodes with AlGaN/GaN high electron mobility transistors

    SciTech Connect (OSTI)

    Liu, Chao; Cai, Yuefei; Liu, Zhaojun; Ma, Jun; Lau, Kei May

    2015-05-04

    We report a metal-interconnection-free integration scheme for InGaN/GaN light emitting diodes (LEDs) and AlGaN/GaN high electron mobility transistors (HEMTs) by combining selective epi removal (SER) and selective epitaxial growth (SEG) techniques. SER of HEMT epi was carried out first to expose the bottom unintentionally doped GaN buffer and the sidewall GaN channel. A LED structure was regrown in the SER region with the bottom n-type GaN layer (n-electrode of the LED) connected to the HEMTs laterally, enabling monolithic integration of the HEMTs and LEDs (HEMT-LED) without metal-interconnection. In addition to saving substrate real estate, minimal interface resistance between the regrown n-type GaN and the HEMT channel is a significant improvement over metal-interconnection. Furthermore, excellent off-state leakage characteristics of the driving transistor can also be guaranteed in such an integration scheme.

  16. A hole modulator for InGaN/GaN light-emitting diodes

    SciTech Connect (OSTI)

    Zhang, Zi-Hui; Kyaw, Zabu; Liu, Wei; Ji, Yun; Wang, Liancheng; Tan, Swee Tiam; Sun, Xiao Wei E-mail: VOLKAN@stanfordalumni.org; Demir, Hilmi Volkan E-mail: VOLKAN@stanfordalumni.org

    2015-02-09

    The low p-type doping efficiency of the p-GaN layer has severely limited the performance of InGaN/GaN light-emitting diodes (LEDs) due to the ineffective hole injection into the InGaN/GaN multiple quantum well (MQW) active region. The essence of improving the hole injection efficiency is to increase the hole concentration in the p-GaN layer. Therefore, in this work, we have proposed a hole modulator and studied it both theoretically and experimentally. In the hole modulator, the holes in a remote p-type doped layer are depleted by the built-in electric field and stored in the p-GaN layer. By this means, the overall hole concentration in the p-GaN layer can be enhanced. Furthermore, the hole modulator is adopted in the InGaN/GaN LEDs, which reduces the effective valance band barrier height for the p-type electron blocking layer from ?332?meV to ?294?meV at 80?A/cm{sup 2} and demonstrates an improved optical performance, thanks to the increased hole concentration in the p-GaN layer and thus the improved hole injection into the MQWs.

  17. AlGaN/GaN heterostructure prepared on a Si (110) substrate via pulsed sputtering

    SciTech Connect (OSTI)

    Watanabe, T.; Ohta, J.; Kondo, T.; Ohashi, M.; Ueno, K.; Kobayashi, A.; Fujioka, H.

    2014-05-05

    GaN films were grown on Si (110) substrates using a low-temperature growth technique based on pulsed sputtering. Reduction of the growth temperature suppressed the strain in the GaN films, leading to an increase in the critical thickness for crack formation. In addition, an AlGaN/GaN heterostructure with a flat heterointerface was prepared using this technique. Furthermore, the existence of a two dimensional electron gas at the heterointerface with a mobility of 1360 cm{sup 2}/Vs and a sheet carrier density of 1.3??10{sup 13}?cm{sup ?2} was confirmed. Finally, the use of the AlGaN/GaN heterostructure in a high electron mobility transistor was demonstrated. These results indicate that low-temperature growth via pulsed sputtering is quite promising for the fabrication of GaN-based electronic devices.

  18. Smart Manufacturing Institute Industry Day Workshop

    Broader source: Energy.gov [DOE]

    AMO hosted an Industry Day workshop to explain the concept, vision, and technology needs associated with support for a Clean Energy Manufacturing Innovation Institute on Smart Manufacturing. The workshop was held on February 25, 2015 at the Georgia Tech Hotel & Conference Center in Atlanta, GA.

  19. Vehicle Technologies Office Merit Review 2015: High-Efficiency...

    Office of Environmental Management (EM)

    On-Board Charger for PEVs Vehicle Technologies Office Merit Review 2015: High-Efficiency High-Density GaN-Based 6.6kW Bidirectional On-Board Charger for PEVs...

  20. Vehicle Technologies Office: Technologies

    Broader source: Energy.gov [DOE]

    To support DOE's goal to provide clean and secure energy, the Vehicle Technologies Office (VTO) invests in research and development that:

  1. Atlanta Central UESC Pilot Project

    Energy Savers [EERE]

    Upgrade - VFD on Pumps 30,151 14 0 0 3,874 0 Heating System Upgrade - Replace Electric Boiler & Pumps 175,063 192 (6,087) 0 36,272 1,667 DDC Controls & Optimization 9,435 15...

  2. Structural and optical properties of InGaNGaN nanowire heterostructures grown by molecular beam epitaxy

    SciTech Connect (OSTI)

    Limbach, F.; Gotschke, T.; Stoica, T.; Calarco, R.; Sutter, E.; Ciston, J.; Cusco, R.; Artus, L.; Kremling, S.; Ho?fling, S.; Worschech, L.; Gru?tzmacher, D.

    2011-01-01

    InGaN/GaN nanowire (NW) heterostructures grown by plasma assisted molecular beam epitaxy were studied in comparison to their GaN and InGaN counterparts. The InGaN/GaN heterostructure NWs are composed of a GaN NW, a thin InGaN shell, and a multifaceted InGaN cap wrapping the top part of the GaN NW. High-resolution transmission electron microscopy (HRTEM) images taken from different parts of a InGaN/GaN NW show a wurtzite structure of the GaN core and the epitaxial InGaN shell around it, while additional crystallographic domains are observed whithin the InGaN cap region. Large changes in the lattice parameter along the wire, from pure GaN to higher In concentration demonstrate the successful growth of a complex InGaN/GaN NW heterostructure. Photoluminescence (PL) spectra of these heterostructure NW ensembles show rather broad and intense emission peak at 2.1 eV. However, ?-PL spectra measured on single NWs reveal a reduced broadening of the visible luminescence. The analysis of the longitudinal optical phonon Raman peak position and its shape reveal a variation in the In content between 20% and 30%, in agreement with the values estimated by PL and HRTEM investigations. The reported studies are important for understanding of the growth and properties of NW heterostructures suitable for applications in optoelectronics and photovoltaics.

  3. 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.

  4. 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.

  5. Highly uniform, multi-stacked InGaAs/GaAs quantum dots embedded in a GaAs nanowire

    SciTech Connect (OSTI)

    Tatebayashi, J. Ota, Y.; Ishida, S.; Nishioka, M.; Iwamoto, S.; Arakawa, Y.

    2014-09-08

    We demonstrate a highly uniform, dense stack of In{sub 0.22}Ga{sub 0.78}As/GaAs quantum dot (QD) structures in a single GaAs nanowire (NW). The size (and hence emission energy) of individual QD is tuned by careful control of the growth conditions based on a diffusion model of morphological evolution of NWs and optical characterization. By carefully tailoring the emission energies of individual QD, dot-to-dot inhomogeneous broadening of QD stacks in a single NW can be as narrow as 9.3?meV. This method provides huge advantages over traditional QD stack using a strain-induced Stranski-Krastanow growth scheme. We show that it is possible to fabricate up to 200 uniform QDs in single GaAs NWs using this growth technique without degradation of the photoluminescence intensity.

  6. Improved InGaN LED System Efficacy and Cost via Droop Reduction |

    Energy Savers [EERE]

    Department of Energy Improved InGaN LED System Efficacy and Cost via Droop Reduction Improved InGaN LED System Efficacy and Cost via Droop Reduction Lead Performer: Lumileds, LLC - San Jose, CA DOE Total Funding: $1,495,990 Cost Share: $374,000 Project Term: 9/1/2015 - 8/31/2017 Funding Opportunity: DOE Announces Selections for SSL Core Technology Research (Round 10), Product Development (Round 10), and U.S. Manufacturing (Round 6) Funding Opportunities Project Objective The overall

  7. 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.

  8. High-performance InGaP/GaAs pnp {delta}-doped heterojunction bipolar transistor

    SciTech Connect (OSTI)

    Tsai, J.-H. Chiu, S.-Y.; Lour, W.-S.; Guo, D.-F.

    2009-07-15

    In this article, a novel InGaP/GaAs pnp {delta}-doped heterojunction bipolar transistor is first demonstrated. Though the valence band discontinuity at InGaP/GaAs heterojunction is relatively large, the addition of a {delta}-doped sheet between two spacer layers at the emitter-base (E-B) junction effectively eliminates the potential spike and increases the confined barrier for electrons, simultaneously. Experimentally, a high current gain of 25 and a relatively low E-B offset voltage of 60 mV are achieved. The offset voltage is much smaller than the conventional InGaP/GaAs pnp HBT. The proposed device could be used for linear amplifiers and low-power complementary integrated circuit applications.

  9. Simplified 2DEG carrier concentration model for composite barrier AlGaN/GaN HEMT

    SciTech Connect (OSTI)

    Das, Palash Biswas, Dhrubes

    2014-04-24

    The self consistent solution of Schrodinger and Poisson equations is used along with the total charge depletion model and applied with a novel approach of composite AlGaN barrier based HEMT heterostructure. The solution leaded to a completely new analytical model for Fermi energy level vs. 2DEG carrier concentration. This was eventually used to demonstrate a new analytical model for the temperature dependent 2DEG carrier concentration in AlGaN/GaN HEMT.

  10. Princeton Plasma Physics Lab - General Atomics (GA)

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

    general-atomics-ga General Atomics en The Scorpion's Strategy: "Catch and Subdue" http:www.pppl.govnode1132

  11. GaTe semiconductor for radiation detection

    DOE Patents [OSTI]

    Payne, Stephen A.; Burger, Arnold; Mandal, Krishna C.

    2009-06-23

    GaTe semiconductor is used as a room-temperature radiation detector. GaTe has useful properties for radiation detectors: ideal bandgap, favorable mobilities, low melting point (no evaporation), non-hygroscopic nature, and availability of high-purity starting materials. The detector can be used, e.g., for detection of illicit nuclear weapons and radiological dispersed devices at ports of entry, in cities, and off shore and for determination of medical isotopes present in a patient.

  12. Accelerated aging of GaAs concentrator solar cells

    SciTech Connect (OSTI)

    Gregory, P.E.

    1982-04-01

    An accelerated aging study of AlGaAs/GaAs solar cells has been completed. The purpose of the study was to identify the possible degradation mechanisms of AlGaAs/GaAs solar cells in terrestrial applications. Thermal storage tests and accelerated AlGaAs corrosion studies were performed to provide an experimental basis for a statistical analysis of the estimated lifetime. Results of this study suggest that a properly designed and fabricated AlGaAs/GaAs solar cell can be mechanically rugged and environmentally stable with projected lifetimes exceeding 100 years.

  13. Epitaxial Growth of GaN-based LEDs on Simple Sacrificial Substrates

    SciTech Connect (OSTI)

    Ian Ferguson; Chris Summers

    2009-12-31

    The objective of this project is to produce alternative substrate technologies for GaN-based LEDs by developing an ALD interlayer of Al{sub 2}O{sub 3} on sacrificial substrates such as ZnO and Si. A sacrificial substrate is used for device growth that can easily be removed using a wet chemical etchant leaving only the thin GaN epi-layer. After substrate removal, the GaN LED chip can then be mounted in several different ways to a metal heat sink/reflector and light extraction techniques can then be applied to the chip and compared for performance. Success in this work will lead to high efficiency LED devices with a simple low cost fabrication method and high product yield as stated by DOE goals for its solid state lighting portfolio.

  14. InGaN/GaN tunnel junctions for hole injection in GaN light emitting diodes

    SciTech Connect (OSTI)

    Krishnamoorthy, Sriram E-mail: rajan@ece.osu.edu; Akyol, Fatih; Rajan, Siddharth E-mail: rajan@ece.osu.edu

    2014-10-06

    InGaN/GaN tunnel junction contacts were grown using plasma assisted molecular beam epitaxy (MBE) on top of a metal-organic chemical vapor deposition (MOCVD)-grown InGaN/GaN blue (450?nm) light emitting diode. A voltage drop of 5.3?V at 100?mA, forward resistance of 2 10{sup ?2} ? cm{sup 2}, and a higher light output power compared to the reference light emitting diodes (LED) with semi-transparent p-contacts were measured in the tunnel junction LED (TJLED). A forward resistance of 5??10{sup ?4} ? cm{sup 2} was measured in a GaN PN junction with the identical tunnel junction contact as the TJLED, grown completely by MBE. The depletion region due to the impurities at the regrowth interface between the MBE tunnel junction and the MOCVD-grown LED was hence found to limit the forward resistance measured in the TJLED.

  15. Lattice-matched epitaxial GaInAsSb/GaSb thermophotovoltaic devices

    SciTech Connect (OSTI)

    Wang, C.A.; Choi, H.K.; Turner, G.W.; Spears, D.L.; Manfra, M.J.; Charache, G.W.

    1997-05-01

    The materials development of Ga{sub 1{minus}x}In{sub x}As{sub y}Sb{sub 1{minus}y} alloys for lattice-matched thermophotovoltaic (TPV) devices is reported. Epilayers with cutoff wavelength 2--2.4 {micro}m at room temperature and lattice-matched to GaSb substrates were grown by both low-pressure organometallic vapor phase epitaxy and molecular beam epitaxy. These layers exhibit high optical and structural quality. For demonstrating lattice-matched thermophotovoltaic devices, p- and n-type doping studies were performed. Several TPV device structures were investigated, with variations in the base/emitter thicknesses and the incorporation of a high bandgap GaSb or AlGaAsSb window layer. Significant improvement in the external quantum efficiency is observed for devices with an AlGaAsSb window layer compared to those without one.

  16. Green cubic GaInN/GaN light-emitting diode on microstructured silicon (100)

    SciTech Connect (OSTI)

    Stark, Christoph J. M.; Detchprohm, Theeradetch; Wetzel, Christian, E-mail: wetzel@ieee.org [Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States) [Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Future Chips Constellation, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180 (United States); Lee, S. C.; Brueck, S. R. J. [Department of Electrical and Computer Engineering and Center for High Technology Materials, University of New Mexico, 1313 Goddard SE, Albuquerque, New Mexico 87106 (United States)] [Department of Electrical and Computer Engineering and Center for High Technology Materials, University of New Mexico, 1313 Goddard SE, Albuquerque, New Mexico 87106 (United States); Jiang, Y.-B. [Department of Earth and Planetary Science, University of New Mexico, Albuquerque, New Mexico 87131 (United States)] [Department of Earth and Planetary Science, University of New Mexico, Albuquerque, New Mexico 87131 (United States)

    2013-12-02

    GaInN/GaN light-emitting diodes free of piezoelectric polarization were prepared on standard electronic-grade Si(100) substrates. Micro-stripes of GaN and GaInN/GaN quantum wells in the cubic crystal structure were grown on intersecting (111) planes of microscale V-grooved Si in metal-organic vapor phase epitaxy, covering over 50% of the wafer surface area. Crystal phases were identified in electron back-scattering diffraction. A cross-sectional analysis reveals a cubic structure virtually free of line defects. Electroluminescence over 20 to 100??A is found fixed at 487?nm (peak), 516?nm (dominant). Such structures therefore should allow higher efficiency, wavelength-stable light emitters throughout the visible spectrum.

  17. Microsoft Word - EOD final final report.doc

    Office of Scientific and Technical Information (OSTI)

    High Selectivity Oxygen Delignification Recipient: Institute of Paper Science and Technology Georgia Institute of Technology 500 10 th St., NW, Atlanta, GA 30332 Award Number: DE-FC07-00ID13870 Subcontractors: Lucian A. Lucia, North Carolina State University/ Georia Institute of Technology Office: 919-515-7707 ; Email : lucian_lucia@ncsu.edu Hasan Jameel, North Carolina State University College of Forest Resources Raleigh, NC 27695-8005 Office #: 919-515-7739 Email: h_jameel@ncsu.edu Contact:

  18. Enhanced thermoelectric transport in modulation-doped GaN/AlGaN core/shell nanowires

    SciTech Connect (OSTI)

    Song, Erdong; Li, Qiming; Swartzentruber, Brian; Pan, Wei; Wang, George T.; Martinez, Julio A.

    2015-11-25

    The thermoelectric properties of unintentionally n-doped core GaN/AlGaN core/shell N-face nanowires are reported. We found that the temperature dependence of the electrical conductivity is consistent with thermally activated carriers with two distinctive donor energies. The Seebeck coefficient of GaN/AlGaN nanowires is more than twice as large as that for the GaN nanowires alone. However, an outer layer of GaN deposited onto the GaN/AlGaN core/shell nanowires decreases the Seebeck coefficient at room temperature, while the temperature dependence of the electrical conductivity remains the same. We attribute these observations to the formation of an electron gas channel within the heavily-doped GaN core of the GaN/AlGaN nanowires. The room-temperature thermoelectric power factor for the GaN/AlGaN nanowires can be four times higher than the GaN nanowires. As a result, selective doping in bandgap engineered core/shell nanowires is proposed for enhancing the thermoelectric power.

  19. Enhanced thermoelectric transport in modulation-doped GaN/AlGaN core/shell nanowires

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

    Song, Erdong; Li, Qiming; Swartzentruber, Brian; Pan, Wei; Wang, George T.; Martinez, Julio A.

    2015-11-25

    The thermoelectric properties of unintentionally n-doped core GaN/AlGaN core/shell N-face nanowires are reported. We found that the temperature dependence of the electrical conductivity is consistent with thermally activated carriers with two distinctive donor energies. The Seebeck coefficient of GaN/AlGaN nanowires is more than twice as large as that for the GaN nanowires alone. However, an outer layer of GaN deposited onto the GaN/AlGaN core/shell nanowires decreases the Seebeck coefficient at room temperature, while the temperature dependence of the electrical conductivity remains the same. We attribute these observations to the formation of an electron gas channel within the heavily-doped GaN coremore » of the GaN/AlGaN nanowires. The room-temperature thermoelectric power factor for the GaN/AlGaN nanowires can be four times higher than the GaN nanowires. As a result, selective doping in bandgap engineered core/shell nanowires is proposed for enhancing the thermoelectric power.« less

  20. Semi-automated lab-on-a-chip for dispensing GA-68 radiotracers

    SciTech Connect (OSTI)

    Weinberg, Irving

    2014-03-12

    We solved a technical problem that is hindering American progress in molecular medicine, and restricting US citizens from receiving optimal diagnostic care. Specifically, the project deals with a mother/daughter generator of positron-emitting radiotracers (Ge-68/Ga-68). These generator systems are approved in Europe but cannot be used in the USA, because of safety issues related to possible breakthrough of long-lived Ge-68 (mother) atoms. Europeans have demonstrated abilities of Ga-68-labeled radiotracers to image cancer foci with high sensitivity and specificity, and to use such methods to effectively plan therapy.The USA Food and Drug Administration (FDA) and Nuclear Regulatory Commission (NRC) have taken the position that every patient administration of Ga-68 should be preceded by an assay demonstrated that Ge-68 breakthrough is within acceptable limits. Breakthrough of parent elements is a sensitive subject at the FDA, as evidenced by the recent recall of Rb-82 generators due to inadvertent administrations of Sr-82. Commercially, there is no acceptable rapid method for assaying breakthrough of Ge-68 prior to each human administration. The gamma emissions of daughter Ga-68 have higher energies than the parent Ge-68, so that the shielding assays typically employed for Mo-99/Tc-99m generators cannot be applied to Ga-68 generators. The half-life of Ga-68 is 68 minutes, so that the standard 10-half-life delay (used to assess breakthrough in Sr-82/Rb-82 generators) cannot be applied to Ga-68 generators. As a result of the aforementioned regulatory requirements, Ga-68 generators are sold in the USA for animal use only.The American clinical communitys inability to utilize Ga-68 generators impairs abilities to treat patients domestically, and puts the USA at a disadvantage in developing exportable products. The proposed DOE project aimed to take advantage of recent technological advances developed for lab-on-a-chip (LOC) applications. Based on our experiences constructing such devices, the proposed microfluidics-based approach could provide cost-effective validation of breakthrough compliance in minutes.

  1. GA-AL-SC | Department of Energy

    Energy Savers [EERE]

    GA-AL-SC GA-AL-SC October 1, 2012 ALA-1-N Wholesale Power Rate Schedule Area: PowerSouth Energy Cooperative System: Georgia-Alabama-South Carolina October 1, 2012 Duke-1-E Wholesale Power Rate Schedule Area: Duke On-System System: Georgia-Alabama-South Carolina October 1, 2012 Duke-2-E Wholesale Power Rate Schedule Area: Central System: Georgia-Alabama-South Carolina October 1, 2012 Duke-3-E Wholesale Power Rate Schedule Area: None System: Georgia-Alabama-South Carolina October 1, 2012 Duke-4-E

  2. GaAs photoconductive semiconductor switch

    DOE Patents [OSTI]

    Loubriel, Guillermo M. (Sandia Park, NM); Baca, Albert G. (Albuquerque, NM); Zutavern, Fred J. (Albuquerque, NM)

    1998-01-01

    A high gain, optically triggered, photoconductive semiconductor switch (PCSS) implemented in GaAs as a reverse-biased pin structure with a passivation layer above the intrinsic GaAs substrate in the gap between the two electrodes of the device. The reverse-biased configuration in combination with the addition of the passivation layer greatly reduces surface current leakage that has been a problem for prior PCSS devices and enables employment of the much less expensive and more reliable DC charging systems instead of the pulsed charging systems that needed to be used with prior PCSS devices.

  3. Structural and optical properties of InGaN--GaN nanowire heterostructures grown by molecular beam epitaxy

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

    Limbach, F.; Gotschke, T.; Stoica, T.; Calarco, R.; Sutter, E.; Ciston, J.; Cusco, R.; Artus, L.; Kremling, S.; Hofling, S.; et al

    2011-01-01

    InGaN/GaN nanowire (NW) heterostructures grown by plasma assisted molecular beam epitaxy were studied in comparison to their GaN and InGaN counterparts. The InGaN/GaN heterostructure NWs are composed of a GaN NW, a thin InGaN shell, and a multifaceted InGaN cap wrapping the top part of the GaN NW. High-resolution transmission electron microscopy (HRTEM) images taken from different parts of a InGaN/GaN NW show a wurtzite structure of the GaN core and the epitaxial InGaN shell around it, while additional crystallographic domains are observed whithin the InGaN cap region. Large changes in the lattice parameter along the wire, from pure GaNmore » to higher In concentration demonstrate the successful growth of a complex InGaN/GaN NW heterostructure. Photoluminescence (PL) spectra of these heterostructure NW ensembles show rather broad and intense emission peak at 2.1 eV. However, μ-PL spectra measured on single NWs reveal a reduced broadening of the visible luminescence. The analysis of the longitudinal optical phonon Raman peak position and its shape reveal a variation in the In content between 20% and 30%, in agreement with the values estimated by PL and HRTEM investigations. The reported studies are important for understanding of the growth and properties of NW heterostructures suitable for applications in optoelectronics and photovoltaics.« less

  4. Structural and optical properties of InGaNGaN nanowire heterostructures grown by molecular beam epitaxy

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

    Limbach, F.; Gotschke, T.; Stoica, T.; Calarco, R.; Sutter, E.; Ciston, J.; Cusco, R.; Artus, L.; Kremling, S.; Ho?fling, S.; et al

    2011-01-01

    InGaN/GaN nanowire (NW) heterostructures grown by plasma assisted molecular beam epitaxy were studied in comparison to their GaN and InGaN counterparts. The InGaN/GaN heterostructure NWs are composed of a GaN NW, a thin InGaN shell, and a multifaceted InGaN cap wrapping the top part of the GaN NW. High-resolution transmission electron microscopy (HRTEM) images taken from different parts of a InGaN/GaN NW show a wurtzite structure of the GaN core and the epitaxial InGaN shell around it, while additional crystallographic domains are observed whithin the InGaN cap region. Large changes in the lattice parameter along the wire, from pure GaNmoreto higher In concentration demonstrate the successful growth of a complex InGaN/GaN NW heterostructure. Photoluminescence (PL) spectra of these heterostructure NW ensembles show rather broad and intense emission peak at 2.1 eV. However, ?-PL spectra measured on single NWs reveal a reduced broadening of the visible luminescence. The analysis of the longitudinal optical phonon Raman peak position and its shape reveal a variation in the In content between 20% and 30%, in agreement with the values estimated by PL and HRTEM investigations. The reported studies are important for understanding of the growth and properties of NW heterostructures suitable for applications in optoelectronics and photovoltaics.less

  5. NREL: Technology Transfer - NREL Awarded $4.9 Million for Small...

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

    Awarded 4.9 Million for Small Business Voucher Pilot July 9, 2015 During the July 8 Clean Energy Manufacturing Initiative's Southeast Regional Summit in Atlanta, Georgia, the...

  6. Investigation of surface-plasmon coupled red light emitting InGaN/GaN multi-quantum well with Ag nanostructures coated on GaN surface

    SciTech Connect (OSTI)

    Li, Yi; Liu, Bin E-mail: rzhang@nju.edu.cn; Zhang, Rong E-mail: rzhang@nju.edu.cn; Xie, Zili; Zhuang, Zhe; Dai, JiangPing; Tao, Tao; Zhi, Ting; Zhang, Guogang; Chen, Peng; Ren, Fangfang; Zhao, Hong; Zheng, Youdou

    2015-04-21

    Surface-plasmon (SP) coupled red light emitting InGaN/GaN multiple quantum well (MQW) structure is fabricated and investigated. The centre wavelength of 5-period InGaN/GaN MQW structure is about 620?nm. The intensity of photoluminescence (PL) for InGaN QW with naked Ag nano-structures (NS) is only slightly increased due to the oxidation of Ag NS as compared to that for the InGaN QW. However, InGaN QW with Ag NS/SiO{sub 2} structure can evidently enhance the emission efficiency due to the elimination of surface oxide layer of Ag NS. With increasing the laser excitation power, the PL intensity is enhanced by 25%53% as compared to that for the SiO{sub 2} coating InGaN QW. The steady-state electric field distribution obtained by the three-dimensional finite-difference time-domain method is different for both structures. The proportion of the field distributed in the Ag NS for the GaN/Ag NS/SiO{sub 2} structure is smaller as compared to that for the GaN/naked Ag NS structure. As a result, the energy loss of localized SP modes for the GaN/naked Ag NS structure will be larger due to the absorption of Ag layer.

  7. Strain-compensated (Ga,In)N/(Al,Ga)N/GaN multiple quantum wells for improved yellow/amber light emission

    SciTech Connect (OSTI)

    Lekhal, K.; Damilano, B. De Mierry, P.; Venngus, P.; Ngo, H. T.; Rosales, D.; Gil, B.; Hussain, S.

    2015-04-06

    Yellow/amber (570600?nm) emitting In{sub x}Ga{sub 1?x}N/Al{sub y}Ga{sub 1?y}N/GaN multiple quantum wells (QWs) have been grown by metal organic chemical vapor deposition on GaN-on- sapphire templates. When the (Al,Ga)N thickness of the barrier increases, the room temperature photoluminescence is red-shifted while its yield increases. This is attributed to an increase of the QW internal electric field and an improvement of the material quality due to the compensation of the compressive strain of the In{sub x}Ga{sub 1?x}N QWs by the Al{sub y}Ga{sub 1?y}N layers, respectively.

  8. Optical spectroscopy of quantum confined states in GaAs/AlGaAs quantum well tubes

    SciTech Connect (OSTI)

    Shi, Teng; Fickenscher, Melodie; Smith, Leigh; Jackson, Howard; Yarrison-Rice, Jan; Gao, Qiang; Tan, Hoe; Jagadish, Chennupati; Etheridge, Joanne; Wong, Bryan M.

    2013-12-04

    We have investigated the quantum confinement of electronic states in GaAs/Al{sub x}Ga{sub 1?x}As nanowire heterostructures which contain radial GaAs quantum wells of either 4nm or 8nm. Photoluminescence and photoluminescence excitation spectroscopy are performed on single nanowires. We observed emission and excitation of electron and hole confined states. Numerical calculations of the quantum confined states using the detailed structural information on the quantum well tubes show excellent agreement with these optical results.

  9. InGaAs/GaAs quantum dot interdiffiusion induced by cap layer overgrowth

    SciTech Connect (OSTI)

    Jasinski, J.; Babinski, A.; Czeczott, M.; Bozek, R.

    2000-06-28

    The effect of thermal treatment during and after growth of InGaAs/GaAs quantum dot (QD) structures was studied. Transmission electron microscopy and atomic force microscopy confirmed the presence of interacting QDs, as was expected from analysis of temperature dependence of QD photoluminescence (PL) peak. The results indicate that the effect of post-growth annealing can be similar to the effect of elevated temperature of capping layer growth. Both, these thermal treatments can lead to a similar In and Ga interdiffiusion resulting in a similar blue-shift of QD PL peak.

  10. Fuels Technologies

    Office of Environmental Management (EM)

    Fuels Technologies Program Mission To develop more energy efficient and environmentally friendly highway transportation technologies that enable America to use less petroleum. --EERE Strategic Plan, October 2002-- Kevin Stork, Team Leader Fuel Technologies & Technology Deployment Vehicle Technologies Program Energy Efficiency and Renewable Energy U.S. Department of Energy DEER 2008 August 6, 2008 Presentation Outline n Fuel Technologies Research Goals Fuels as enablers for advanced engine

  11. On strongly GA-convex functions and stochastic processes

    SciTech Connect (OSTI)

    Bekar, Nurgl Okur; Akdemir, Hande Gnay; ??can, ?mdat

    2014-08-20

    In this study, we introduce strongly GA-convex functions and stochastic processes. We provide related well-known Kuhn type results and Hermite-Hadamard type inequality for strongly GA-convex functions and stochastic processes.

  12. High-field quasi-ballistic transport in AlGaN/GaN heterostructures

    SciTech Connect (OSTI)

    Danilchenko, B. A.; Tripachko, N. A.; Belyaev, A. E.; Vitusevich, S. A. Hardtdegen, H.; Lth, H.

    2014-02-17

    Mechanisms of electron transport formation in 2D conducting channels of AlGaN/GaN heterostructures in extremely high electric fields at 4.2?K have been studied. Devices with a narrow constriction for the current flow demonstrate high-speed electron transport with an electron velocity of 6.8??10{sup 7}?cm/s. Such a velocity is more than two times higher than values reported for conventional semiconductors and about 15% smaller than the limit value predicted for GaN. Superior velocity is attained in the channel with considerable carrier reduction. The effect is related to a carrier runaway phenomenon. The results are in good agreement with theoretical predictions for GaN-based materials.

  13. Exploration Technologies - Technology Needs Assessment

    SciTech Connect (OSTI)

    Greene, Amanda I.; Thorsteinsson, Hildigunnur; Reinhardt, Tim; Solomon, Samantha; James, Mallory

    2011-06-01

    This assessment is a critical component of ongoing technology roadmapping efforts, and will be used to guide the Geothermal Technology Program's research and development.

  14. InGaAs/GaAs (110) quantum dot formation via step meandering

    SciTech Connect (OSTI)

    Diez-Merino, Laura; Tejedor, Paloma

    2011-07-01

    InGaAs (110) semiconductor quantum dots (QDs) offer very promising prospects as a material base for a new generation of high-speed spintronic devices, such as single electron transistors for quantum computing. However, the spontaneous formation of InGaAs QDs is prevented by two-dimensional (2D) layer-by-layer growth on singular GaAs (110) substrates. In this work we have studied, by using atomic force microscopy and photoluminescence spectroscopy (PL), the growth of InGaAs/GaAs QDs on GaAs (110) stepped substrates by molecular beam epitaxy (MBE), and the modification of the adatom incorporation kinetics to surface steps in the presence of chemisorbed atomic hydrogen. The as-grown QDs exhibit lateral dimensions below 100 nm and emission peaks in the 1.35-1.37 eV range. It has been found that a step meandering instability derived from the preferential attachment of In adatoms to [110]-step edges relative to [11n]-type steps plays a key role in the destabilization of 2D growth that leads to 3D mound formation on both conventional and H-terminated vicinal substrates. In the latter case, the driving force for 3D growth via step meandering is enhanced by H-induced upward mass transport in addition to the lower energy cost associated with island formation on H-terminated substrates, which results in a high density array of InGaAs/GaAs dots selectively nucleated on the terrace apices with reduced lateral dimensions and improved PL efficiency relative to those of conventional MBE-grown samples.

  15. AlGaAs/GaAs photovoltaic converters for high power narrowband radiation

    SciTech Connect (OSTI)

    Khvostikov, Vladimir; Kalyuzhnyy, Nikolay; Mintairov, Sergey; Potapovich, Nataliia; Shvarts, Maxim; Sorokina, Svetlana; Andreev, Viacheslav; Luque, Antonio

    2014-09-26

    AlGaAs/GaAs-based laser power PV converters intended for operation with high-power (up to 100 W/cm{sup 2}) radiation were fabricated by LPE and MOCVD techniques. Monochromatic (? = 809 nm) conversion efficiency up to 60% was measured at cells with back surface field and low (x = 0.2) Al concentration 'window'. Modules with a voltage of 4 V and the efficiency of 56% were designed and fabricated.

  16. GaNPAs Solar Cells Lattice-Matched To GaP: Preprint

    SciTech Connect (OSTI)

    Geisz, J. F.; Friedman, D. J.; Kurtz, S.

    2002-05-01

    This conference paper describes the III-V semiconductors grown on silicon substrates are very attractive for lower-cost, high-efficiency multijunction solar cells, but lattice-mismatched alloys that result in high dislocation densities have been unable to achieve satisfactory performance. GaNxP1-x-yAsy is a direct-gap III-V alloy that can be grown lattice-matched to Si when y= 4.7x - 0.1. We propose the use of lattice-matched GaNPAs on silicon for high-efficiency multijunction solar cells. We have grown GaNxP1-x-yAsy on GaP (with a similar lattice constant to silicon) by metal-organic chemical vapor phase epitaxy with direct band-gaps in the range of 1.5 to 2.0 eV. We demonstrate the performance of single-junction GaNxP1-x-yAsy solar cells grown on GaP substrates and discuss the prospects for the development of monolithic high-efficiency multijunction solar cells based on silicon substrates.

  17. NREL: Technology Transfer - Technology Partnership Agreements

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

    Ombuds. Printable Version Technology Transfer Home About Technology Transfer Technology Partnership Agreements Agreements for Commercializing Technology CRADAs Work for...

  18. High Impact Technology Catalyst: Technology Deployment Strategies...

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

    Catalyst: Technology Deployment Strategies High Impact Technology Catalyst: Technology Deployment Strategies The Energy Department released the High Impact Technology Catalyst: ...

  19. Room-temperature mid-infrared "M"-type GaAsSb/InGaAs quantum...

    Office of Scientific and Technical Information (OSTI)

    Room-temperature mid-infrared "M"-type GaAsSbInGaAs quantum well lasers on InP substrate Citation Details In-Document Search Title: Room-temperature mid-infrared "M"-type GaAsSb...

  20. Lattice-Mismatched GaAs/InGaAs Two-Junction Solar Cells by Direct Wafer Bonding

    SciTech Connect (OSTI)

    Tanabe, K.; Aiken, D. J.; Wanlass, M. W.; Morral, A. F.; Atwater, H. A.

    2006-01-01

    Direct bonded interconnect between subcells of a lattice-mismatched III-V compound multijunction cell would enable dislocation-free active regions by confining the defect network needed for lattice mismatch accommodation to tunnel junction interfaces, while metamorphic growth inevitably results in less design flexibility and lower material quality than is desirable. The first direct-bond interconnected multijunction solar cell, a two-terminal monolithic GaAs/InGaAs two-junction solar cell, is reported and demonstrates viability of direct wafer bonding for solar cell applications. The tandem cell open-circuit voltage was approximately the sum of the subcell open-circuit voltages. This achievement shows direct bonding enables us to construct lattice-mismatched III-V multijunction solar cells and is extensible to an ultrahigh efficiency InGaP/GaAs/InGaAsP/InGaAs four-junction cell by bonding a GaAs-based lattice-matched InGaP/GaAs subcell and an InP-based lattice-matched InGaAsP/InGaAs subcell. The interfacial resistance experimentally obtained for bonded GaAs/InP smaller than 0.10 Ohm-cm{sup 2} would result in a negligible decrease in overall cell efficiency of {approx}0.02%, under 1-sun illumination.

  1. Properties of (Ga,Mn)As codoped with Li

    SciTech Connect (OSTI)

    Miyakozawa, Shohei; Chen, Lin; Matsukura, Fumihiro; Ohno, Hideo

    2014-06-02

    We grow Li codoped (Ga,Mn)As layers with nominal Mn composition up to 0.15 by molecular beam epitaxy. The layers before and after annealing are characterized by x-ray diffraction, transport, magnetization, and ferromagnetic resonance measurements. The codoping with Li reduces the lattice constant and electrical resistivity of (Ga,Mn)As after annealing. We find that (Ga,Mn)As:Li takes similar Curie temperature to that of (Ga,Mn)As, but with pronounced magnetic moments and in-plane magnetic anisotropy, indicating that the Li codoping has nontrivial effects on the magnetic properties of (Ga,Mn)As.

  2. Vehicle Technologies Office - Materials Technologies

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

    Vehicle Technologies Office Materials Technologies Ed Owens Jerry Gibbs Will Joost eere.energy.gov 2 | Vehicle Technologies Program Materials Technologies Materials Technologies $36.9 M Lightweight Materials $28.0 M Values are FY14 enacted Propulsion Materials $8.9 M Properties and Manufacturing Multi-Material Enabling Modeling & Computational Mat. Sci. Engine Materials, Cast Al & Fe High Temp Alloys Exhaust Sys. Materials, Low T Catalysts Lightweight Propulsion FY13 Enacted $27.5 M

  3. Three-junction solar cells comprised of a thin-film GaInP/GaAs tandem cell mechanically stacked on a Si cell

    SciTech Connect (OSTI)

    Yazawa, Y.; Tamura, K.; Watahiki, S.; Kitatani, T.; Ohtsuka, H.; Warabisako, T.

    1997-12-31

    Three-junction tandem solar cells were fabricated by mechanical stacking of a thin-film GaInP/GaAs monolithic tandem cell and a Si cell. The epitaxial lift-off (ELO) technique was used for the thinning of GaInP/GaAs tandem cells. Both spectral responses of the GaInP top cell and the GaAs middle cell in the thin-film GaInP/GaAs monolithic tandem cell were conserved. The Si cell performance has been improved by reducing the absorption loss in the GaAs substrate.

  4. Reactive codoping of GaAlInP compound semiconductors

    DOE Patents [OSTI]

    Hanna, Mark Cooper (Boulder, CO); Reedy, Robert (Golden, CO)

    2008-02-12

    A GaAlInP compound semiconductor and a method of producing a GaAlInP compound semiconductor are provided. The apparatus and method comprises a GaAs crystal substrate in a metal organic vapor deposition reactor. Al, Ga, In vapors are prepared by thermally decomposing organometallic compounds. P vapors are prepared by thermally decomposing phospine gas, group II vapors are prepared by thermally decomposing an organometallic group IIA or IIB compound. Group VIB vapors are prepared by thermally decomposing a gaseous compound of group VIB. The Al, Ga, In, P, group II, and group VIB vapors grow a GaAlInP crystal doped with group IIA or IIB and group VIB elements on the substrate wherein the group IIA or IIB and a group VIB vapors produced a codoped GaAlInP compound semiconductor with a group IIA or IIB element serving as a p-type dopant having low group II atomic diffusion.

  5. Chemical beam epitaxy growth of AlGaAs/GaAs tunnel junctions using trimethyl aluminium for multijunction solar cells

    SciTech Connect (OSTI)

    Paquette, B.; DeVita, M.; Turala, A.; Kolhatkar, G.; Boucherif, A.; Jaouad, A.; Aimez, V.; Ars, R.; Wilkins, M.; Wheeldon, J. F.; Walker, A. W.; Hinzer, K.; Fafard, S.

    2013-09-27

    AlGaAs/GaAs tunnel junctions for use in high concentration multijunction solar cells were designed and grown by chemical beam epitaxy (CBE) using trimethyl aluminium (TMA) as the p-dopant source for the AlGaAs active layer. Controlled hole concentration up to 4?10{sup 20} cm{sup ?3} was achieved through variation in growth parameters. Fabricated tunnel junctions have a peak tunneling current up to 6140 A/cm{sup 2}. These are suitable for high concentration use and outperform GaAs/GaAs tunnel junctions.

  6. Available Technologies

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

    application. Search Our Technologies submit Advanced Materials Advanced Materials Biotechnology Biotechnology Chemistry Chemistry Energy Energy High Performance Computing:...

  7. Licensing Technology

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

    Licensing Technology Licensing Technology The primary function of Los Alamos Licensing Program is to move Los Alamos technology to the marketplace for the benefit of the U.S. economy. Our intellectual property may be licensed for commercial use, research applications, and U.S. government use. Contact thumbnail of Marcus Lucero Head of Licensing Marcus Lucero Richard P. Feynman Center for Innovation (505) 665-6569 Email Although Los Alamos's primary mission is national security, our technologies

  8. Technology Opportunities

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

    Intellectual Property » Technology Opportunities Technology Opportunities We deliver innovation through an integrated portfolio of R&D work across our key national security sponsoring agencies, enhanced by the ideas developed through our strategic internal investments. Contact Business Development Team Richard P. Feynman Center for Innovation (505) 665-9090 Email Periodically, the Laboratory notifies the public of technologies and capabilities that may be of interest. These technologies may

  9. Technology Partnering

    Energy Savers [EERE]

    on Technology Transfer and Related Technology Partnering Activities at the National Laboratories and Other Facilities Fiscal Years 2009-2013 Report to Congress May 2015 United States Department of Energy Washington, DC 20585 Message from the Secretary The Report on Technology Transfer and Related Partnering Activities at the National Laboratories and Other Facilities for Fiscal Year 2009-2013 is prepared in accordance with the requirements of the Technology Transfer and Commercialization Act of

  10. Electron tunneling spectroscopy study of electrically active traps in AlGaN/GaN high electron mobility transistors

    SciTech Connect (OSTI)

    Yang, Jie Cui, Sharon; Ma, T. P.; Hung, Ting-Hsiang; Nath, Digbijoy; Krishnamoorthy, Sriram; Rajan, Siddharth

    2013-11-25

    We investigate the energy levels of electron traps in AlGaN/GaN high electron mobility transistors by the use of electron tunneling spectroscopy. Detailed analysis of a typical spectrum, obtained in a wide gate bias range and with both bias polarities, suggests the existence of electron traps both in the bulk of AlGaN and at the AlGaN/GaN interface. The energy levels of the electron traps have been determined to lie within a 0.5?eV band below the conduction band minimum of AlGaN, and there is strong evidence suggesting that these traps contribute to Frenkel-Poole conduction through the AlGaN barrier.

  11. 0.7-eV GaInAs Junction for a GaInP/GaAs/GaInAs(1eV)/GaInAs(0.7eV) Four-Junction Solar Cell

    SciTech Connect (OSTI)

    Friedman, D. J.; Geisz, J. F.; Norman, A. G.; Wanlass, M. W.; Kurtz, S. R.

    2006-01-01

    We discuss recent developments in III-V multijunction solar cells, focusing on adding a fourth junction to the Ga{sub 0.5}In{sub 0.5} P/GaAs/Ga{sub 0.75}In{sub 0.25}As inverted three-junction cell. This cell, grown inverted on GaAs so that the lattice-mismatched Ga{sub 0.75}In{sub 0.25}As third junction is the last one grown, has demonstrated 38% efficiency, and 40% is likely in the near future. To achieve still further gains, a lower-bandgap Ga{sub x}In{sub 1-x}As fourth junction could be added to the three-junction structure for a four-junction cell whose efficiency could exceed 45% under concentration. Here, we present the initial development of the Ga{sub x}In{sub 1-x}As fourth junction. Junctions of various bandgaps ranging from 0.88 to 0.73 eV were grown, in order to study the effect of the different amounts of lattice mismatch. At a bandgap of 0.88 eV, junctions were obtained with very encouraging {approx}80% quantum efficiency, 57% fill factor, and 0.36 eV open-circuit voltage. The device performance degrades with decreasing bandgap (i.e., increasing lattice mismatch). We model the four-junction device efficiency vs. fourth junction bandgap to show that an 0.7-eV fourth-junction bandgap, while optimal if it could be achieved in practice, is not necessary; an 0.9-eV bandgap would still permit significant gains in multijunction cell efficiency while being easier to achieve than the lower-bandgap junction.

  12. Energy Technologies

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

    Technologies Our Vision National User Facilities Research Areas In Focus Global Solutions ⇒ Navigate Section Our Vision National User Facilities Research Areas In Focus Global Solutions Energy Technologies Area (ETA) Building Technology & Urban Systems Energy Analysis & Environmental Impacts Energy Storage & Distributed Resources

  13. Technology Assessment

    Energy Savers [EERE]

    - FOR OFFICIAL USE ONLY - DRAFT 1 Advanced Composites Materials and their Manufacture 1 Technology Assessment 2 Contents 3 1. Introduction to the Technology/System ................................................................................................ 2 4 2. Technology Potential and Assessment .................................................................................................. 4 5 2.1 The Potential for Advanced Composites for Clean Energy Application Areas

  14. Vehicle Technologies Office Merit Review 2015: High-Efficiency High-Density

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

    GaN-Based 6.6kW Bidirectional On-Board Charger for PEVs | Department of Energy High-Efficiency High-Density GaN-Based 6.6kW Bidirectional On-Board Charger for PEVs Vehicle Technologies Office Merit Review 2015: High-Efficiency High-Density GaN-Based 6.6kW Bidirectional On-Board Charger for PEVs Presentation given by Delta Products Corporation at 2015 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about high-efficiency

  15. Analysis of defects in GaAsN grown by chemical beam epitaxy on high index GaAs substrates

    SciTech Connect (OSTI)

    Bouzazi, Boussairi; Kojima, Nobuaki; Ohshita, Yoshio; Yamaguchi, Masafumi

    2013-09-27

    The lattice defects in GaAsN grown by chemical beam epitaxy on GaAs 311B and GaAs 10A toward [110] were characterized and discussed by using deep level transient spectroscopy (DLTS) and on the basis of temperature dependence of the junction capacitances (C{sub J}). In one hand, GaAsN films grown on GaAs 311B and GaAs 10A showed n-type and p-type conductivities, respectively although the similar and simultaneous growth conditions. This result is indeed in contrast to the common known effect of N concentration on the type of conductivity, since the surface 311B showed a significant improvement in the incorporation of N. Furthermore, the temperature dependence of C{sub J} has shown that GaAs 311B limits the formation of N-H defects. In the other hand, the energy states in the forbidden gap of GaAsN were obtained. Six electron traps, E1 to E6, were observed in the DLTS spectrum of GaAsN grown on GaAs 311B, with apparent activation energies of 0.02, 0.14, 0.16, 0.33, 0.48, and 0.74 eV below the bottom edge of the conduction band, respectively. In addition, four hole traps, H1 to H4, were observed in the DLTS spectrum of GaAsN grown on GaAs 10A, with energy depths of 0.13, 0.20, 0.39, and 0.52 eV above the valence band maximum of the alloy, respectively. Hence, the surface morphology of the GaAs substrate was found to play a key factor role in clarifying the electrical properties of GaAsN grown by CBE.

  16. Photocapacitance study of type-II GaSb/GaAs quantum ring solar cells

    SciTech Connect (OSTI)

    Wagener, M. C.; Botha, J. R.; Carrington, P. J.; Krier, A.

    2014-01-07

    In this study, the density of states associated with the localization of holes in GaSb/GaAs quantum rings are determined by the energy selective charging of the quantum ring distribution. The authors show, using conventional photocapacitance measurements, that the excess charge accumulated within the type-II nanostructures increases with increasing excitation energies for photon energies above 0.9?eV. Optical excitation between the localized hole states and the conduction band is therefore not limited to the ?(k?=?0) point, with pseudo-monochromatic light charging all states lying within the photon energy selected. The energy distribution of the quantum ring states could consequently be accurately related from the excitation dependence of the integrated photocapacitance. The resulting band of localized hole states is shown to be well described by a narrow distribution centered 407?meV above the GaAs valence band maximum.

  17. Efficiency enhancement of InGaN/GaN solar cells with nanostructures

    SciTech Connect (OSTI)

    Bai, J.; Yang, C. C.; Athanasiou, M.; Wang, T.

    2014-02-03

    We demonstrate InGaN/GaN multi-quantum-well solar cells with nanostructures operating at a wavelength of 520?nm. Nanostructures with a periodic nanorod or nanohole array are fabricated by means of modified nanosphere lithography. Under 1 sun air-mass 1.5 global spectrum illumination, a fill factor of 50 and an open circuit voltage of 1.9?V are achieved in spite of very high indium content in InGaN alloys usually causing degradation of crystal quality. Both the nanorod array and the nanohole array significantly improve the performance of solar cells, while a larger enhancement is observed for the nanohole array, where the conversion efficiency is enhanced by 51%.

  18. A InGaN/GaN quantum dot green ({lambda}=524 nm) laser

    SciTech Connect (OSTI)

    Zhang Meng; Banerjee, Animesh; Lee, Chi-Sen; Hinckley, John M.; Bhattacharya, Pallab

    2011-05-30

    The characteristics of self-organized InGaN/GaN quantum dot lasers are reported. The laser heterostructures were grown on c-plane GaN substrates by plasma-assisted molecular beam epitaxy and the laser facets were formed by focused ion beam etching with gallium. Emission above threshold is characterized by a peak at 524 nm (green) and linewidth of 0.7 nm. The lowest measured threshold current density is 1.2 kA/cm{sup 2} at 278 K. The slope and wall plug efficiencies are 0.74 W/A and {approx}1.1%, respectively, at 1.3 kA/cm{sup 2}. The value of T{sub 0}=233 K in the temperature range of 260-300 K.

  19. Graphene in ohmic contact for both n-GaN and p-GaN

    SciTech Connect (OSTI)

    Zhong, Haijian; Liu, Zhenghui; Shi, Lin; Xu, Gengzhao; Fan, Yingmin; Huang, Zengli; Wang, Jianfeng; Ren, Guoqiang; Xu, Ke

    2014-05-26

    The wrinkles of single layer graphene contacted with either n-GaN or p-GaN were found both forming ohmic contacts investigated by conductive atomic force microscopy. The local IV results show that some of the graphene wrinkles act as high-conductive channels and exhibiting ohmic behaviors compared with the flat regions with Schottky characteristics. We have studied the effects of the graphene wrinkles using density-functional-theory calculations. It is found that the standing and folded wrinkles with zigzag or armchair directions have a tendency to decrease or increase the local work function, respectively, pushing the local Fermi level towards n- or p-type GaN and thus improving the transport properties. These results can benefit recent topical researches and applications for graphene as electrode material integrated in various semiconductor devices.

  20. Photoluminescence studies of individual and few GaSb/GaAs quantum rings

    SciTech Connect (OSTI)

    Young, M. P.; Woodhead, C. S.; Roberts, J.; Noori, Y. J.; Noble, M. T.; Krier, A.; Hayne, M.; Young, R. J.; Smakman, E. P.; Koenraad, P. M.

    2014-11-15

    We present optical studies of individual and few GaSb quantum rings embedded in a GaAs matrix. Contrary to expectation for type-II confinement, we measure rich spectra containing sharp lines. These lines originate from excitonic recombination and are observed to have resolution-limited full-width at half maximum of 200 ?eV. The detail provided by these measurements allows the characteristic type-II blueshift, observed with increasing excitation power, to be studied at the level of individual nanostructures. These findings are in agreement with hole-charging being the origin of the observed blueshift.

  1. Application of the ASME code in the design of the GA-4 and GA-9 casks

    SciTech Connect (OSTI)

    Mings, W.J. ); Koploy, M.A. )

    1992-01-01

    General Atomics (GA) is developing two spent fuel shipping casks for transport by legal weight truck (LWT). The casks are designed to the loading, environmental conditions and safety requirements defined in Title 10 of the Code of Federal Regulations, Part 71 (10CFR71). To ensure that all components of the cask meet the 10CFR71 rules, GA established structural design criteria for each component based on NRC Regulatory Guides and the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code). This paper discusses the criteria used for different cask components, how they were applied and the conservatism and safety margins built into the criteria and assumption.

  2. Application of the ASME code in the design of the GA-4 and GA-9 casks

    SciTech Connect (OSTI)

    Mings, W.J.; Koploy, M.A.

    1992-08-01

    General Atomics (GA) is developing two spent fuel shipping casks for transport by legal weight truck (LWT). The casks are designed to the loading, environmental conditions and safety requirements defined in Title 10 of the Code of Federal Regulations, Part 71 (10CFR71). To ensure that all components of the cask meet the 10CFR71 rules, GA established structural design criteria for each component based on NRC Regulatory Guides and the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code). This paper discusses the criteria used for different cask components, how they were applied and the conservatism and safety margins built into the criteria and assumption.

  3. Temperature dependency of the emission properties from positioned In(Ga)As/GaAs quantum dots

    SciTech Connect (OSTI)

    Braun, T.; Schneider, C.; Maier, S.; Forchel, A.; Hfling, S.; Kamp, M.; Igusa, R.; Iwamoto, S.; Arakawa, Y.

    2014-09-15

    In this letter we study the influence of temperature and excitation power on the emission linewidth from site-controlled InGaAs/GaAs quantum dots grown on nanoholes defined by electron beam lithography and wet chemical etching. We identify thermal electron activation as well as direct exciton loss as the dominant intensity quenching channels. Additionally, we carefully analyze the effects of optical and acoustic phonons as well as close-by defects on the emission linewidth by means of temperature and power dependent micro-photoluminescence on single quantum dots with large pitches.

  4. Origins of ion irradiation-induced Ga nanoparticle motion on GaAs surfaces

    SciTech Connect (OSTI)

    Kang, M.; Wu, J. H.; Chen, H. Y.; Thornton, K.; Goldman, R. S. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States)] [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States); Sofferman, D. L. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States) [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States); Department of Physics, Adelphi University, Garden City, New York 11530-0701 (United States); Beskin, I. [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1040 (United States)] [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1040 (United States)

    2013-08-12

    We have examined the origins of ion irradiation-induced nanoparticle (NP) motion. Focused-ion-beam irradiation of GaAs surfaces induces random walks of Ga NPs, which are biased in the direction opposite to that of ion beam scanning. Although the instantaneous NP velocities are constant, the NP drift velocities are dependent on the off-normal irradiation angle, likely due to a difference in surface non-stoichiometry induced by the irradiation angle dependence of the sputtering yield. It is hypothesized that the random walks are initiated by ion irradiation-induced thermal fluctuations, with biasing driven by anisotropic mass transport.

  5. Simulation of quantum dots size and spacing effect for intermediate band solar cell application based on InAs quantum dots arrangement in GaAs

    SciTech Connect (OSTI)

    Hendra, P. I. B. Rahayu, F. Darma, Y.

    2014-03-24

    Intermediate band solar cell (IBSC) has become a promising technology in increasing solar cell efficiency. In this work we compare absorption coefficient profile between InAs quantum dots with GaAs bulk. We calculate the efficiency of GaAs bulk and GaAs doped with 2, 5, and 10 nm InAs quantum dot. Effective distances in quantum dot arrangement based on electron tunneling consideration were also calculated. We presented a simple calculation method with low computing power demand. Results showed that arrangement of quantum dot InAs in GaAs can increase solar cell efficiency from 23.9 % initially up to 60.4%. The effective distance between two quantum dots was found 2 nm in order to give adequate distance to prevent electron tunneling and wave functions overlap.

  6. Foreign Obligations Implementation Status Presentation

    National Nuclear Security Administration (NNSA)

    January 13, 2004 Crowne Plaza Ravinia Atlanta, January 13, 2004 Crowne Plaza Ravinia Atlanta, Georgia Georgia Obligations Accounting Implementation Workshop Obligations Accounting Implementation Workshop Foreign Obligations Implementation Status Brian G. Horn U.S. Nuclear Regulatory Commission January 13, 2004 Obligations Accounting Implementation Workshop January 13, 2 Obligations Accounting Implementation Workshop January 13, 2004 Crowne Plaza Ravinia Atlanta, GA 004 Crowne Plaza Ravinia

  7. Technology '90

    SciTech Connect (OSTI)

    Not Available

    1991-01-01

    The US Department of Energy (DOE) laboratories have a long history of excellence in performing research and development in a number of areas, including the basic sciences, applied-energy technology, and weapons-related technology. Although technology transfer has always been an element of DOE and laboratory activities, it has received increasing emphasis in recent years as US industrial competitiveness has eroded and efforts have increased to better utilize the research and development resources the laboratories provide. This document, Technology '90, is the latest in a series that is intended to communicate some of the many opportunities available for US industry and universities to work with the DOE and its laboratories in the vital activity of improving technology transfer to meet national needs. Technology '90 is divided into three sections: Overview, Technologies, and Laboratories. The Overview section describes the activities and accomplishments of the DOE research and development program offices. The Technologies section provides descriptions of new technologies developed at the DOE laboratories. The Laboratories section presents information on the missions, programs, and facilities of each laboratory, along with a name and telephone number of a technology transfer contact for additional information. Separate papers were prepared for appropriate sections of this report.

  8. Distributed bragg reflector using AIGaN/GaN

    DOE Patents [OSTI]

    Waldrip, Karen E.; Lee, Stephen R.; Han, Jung

    2004-08-10

    A supported distributed Bragg reflector or superlattice structure formed from a substrate, a nucleation layer deposited on the substrate, and an interlayer deposited on the nucleation layer, followed by deposition of (Al,Ga,B)N layers or multiple pairs of (Al,Ga,B)N/(Al,Ga,B)N layers, where the interlayer is a material selected from AlN, Al.sub.x Ga.sub.1-x N, and AlBN with a thickness of approximately 20 to 1000 angstroms. The interlayer functions to reduce or eliminate the initial tensile growth stress, thereby reducing cracking in the structure. Multiple interlayers utilized in an AlGaN/GaN DBR structure can eliminate cracking and produce a structure with a reflectivity value greater than 0.99.

  9. High-Efficiency GaInP/GaAs Tandem Solar Cells

    SciTech Connect (OSTI)

    Bertness, K. A.; Friedman, D. J.; Kurtz, S. R.; Kibbler, A. E.; Cramer, C.; Olson, J. M.

    1996-09-01

    GaInP/GaAs tandem solar cells have achieved efficiencies between 25.7-30.2%, depending on illumination conditions. The efficiencies are the highest confirmed two-terminal values measured for any solar cell within each standard illumination category. The monolithic, series-connected design of the tandem cells allows them to be substituted for silicon or gallium arsenide cells in photovoltaic panel systems with minimal design changes. The advantages of using GaInP/GaAs tandem solar cells in space and terrestrial applications are discussed primarily in terms of the reduction in balance-of-system costs that accrues when using a higher efficiency cell. The new efficiency values represent a significant improvement over previous efficiencies for this materials system, and we identify grid design, back interface passivation, and top interface passivation as the three key factors leading to this improvement. In producing the high-efficiency cells, we have addressed nondestructive diagnostics and materials growth reproducibility as well as peak cell performance.

  10. High-efficiency GaInP/GaAs tandem solar cells

    SciTech Connect (OSTI)

    Bertness, K.A.; Friedman, D.J.; Kurtz, S.R.; Kibbler, A.E.; Kramer, C.; Olson, J.M.

    1994-12-01

    GaInP/GaAs tandem solar cells have achieved new record efficiencies, specifically 25.7% under air-mass 0 (AM0) illumination, 29.5% under AM 1.5 global (AM1.5G) illumination, and 30.2% at 140-180x concentration under AM 1.5 direct (AM1.5D) illumination. These values are the highest two-terminal efficiencies achieved by any solar cell under these illumination conditions. The monolithic, series-connected design of the tandem cells allows them to be substituted for silicon or gallium arsenide cells in photovoltaic panel systems with minimal design changes. The advantages of using GaInP/GaAs tandem solar cells in space and terrestrial applications are discussed primarily in terms of the reduction in balance-of-system costs that accrues when using a higher efficiency cell. The new efficiency values represent a significant improvement over previous efficiencies for this materials system, and we identify grid design, back interface passivation, and top interface passivation as the three key factors leading to this improvement. In producing the high-efficiency cells, we have addressed nondestructive diagnostics and materials growth reproducibility as well as peak cell performance. 31 refs.

  11. Localized corrosion of GaAs surfaces and formation of porous GaAs

    SciTech Connect (OSTI)

    Schmuki, P.; Vitus, C.M.; Isaacs, H.S.; Fraser, J.; Graham, M.J.

    1995-12-01

    The present work deals with pitting corrosion of p- and n-type GaAs (100). Pit growth can be electrochemically initiated on both conduction types in chloride-containing solutions and leads after extended periods of time to the formation of a porous GaAs structure. In the case of p-type material, localized corrosion is only observed if a passivating film is present on the surface, otherwise -- e.g. in acidic solutions -- the material suffers from a uniform attack (electropolishing) which is independent of the anion present. In contrast, pitting corrosion of n-type material can be triggered independent of the presence of an oxide film. This is explained in terms of the different current limiting factor for the differently doped materials (oxide film in the case of the p- and a space charge layer in the case of the n-GaAs). The porous structure was characterized by SEM, EDX and AES, and consists mainly of GaAs. From scratch experiments it is clear that the pit initiation process is strongly influenced by surface defects. For n-type material, AFM investigations show that light induced roughening of the order of several hundred nm occurs under non-passivating conditions. This nm- scale roughening however does not affect the pitting process.

  12. Multijunction GaInP/GaInAs/Ge solar cells with Bragg reflectors

    SciTech Connect (OSTI)

    Emelyanov, V. M. Kalyuzhniy, N. A.; Mintairov, S. A.; Shvarts, M. Z.; Lantratov, V. M.

    2010-12-15

    Effect of subcell parameters on the efficiency of GaInP/Ga(In)As/Ge tandem solar cells irradiated with 1-MeV electrons at fluences of up to 3 x 10{sup 15} cm{sup -2} has been theoretically studied. The optimal thicknesses of GaInP and GaInAs subcells, which provide the best photocurrent matching at various irradiation doses in solar cells with and without built-in Bragg reflectors, were determined. The dependences of the photoconverter efficiency on the fluence of 1-MeV electrons and on the time of residence in the geostationary orbit were calculated for structures optimized to the beginning and end of their service lives. It is shown that the optimization of the subcell heterostructures for a rated irradiation dose and the introduction of Bragg reflectors into the structure provide a 5% overall increase in efficiency for solar cells operating in the orbit compared with unoptimized cells having no Bragg reflector.

  13. AlGaAs/InGaAlP tunnel junctions for multijunction solar cells

    SciTech Connect (OSTI)

    SHARPS,P.R.; LI,N.Y.; HILLS,J.S.; HOU,H.; CHANG,PING-CHIH; BACA,ALBERT G.

    2000-05-16

    Optimization of GaInP{sub 2}/GaAs dual and GaInP{sub 2}/GaAs/Ge triple junction cells, and development of future generation monolithic multi-junction cells will involve the development of suitable high bandgap tunnel junctions. There are three criteria that a tunnel junction must meet. First, the resistance of the junction must be kept low enough so that the series resistance of the overall device is not increased. For AMO, 1 sun operation, the tunnel junction resistance should be below 5 x 10{sup {minus}2} {Omega}-cm. Secondly, the peak current density for the tunnel junction must also be larger than the J{sub sc} of the cell so that the tunnel junction I-V curve does not have a deleterious effect on the I-V curve of the multi-junction device. Finally, the tunnel junction must be optically transparent, i.e., there must be a minimum of optical absorption of photons that will be collected by the underlying subcells. The paper reports the investigation of four high bandgap tunnel junctions grown by metal-organic chemical vapor deposition.

  14. Photoluminescence from GaAs nanodisks fabricated by using combination...

    Office of Scientific and Technical Information (OSTI)

    GaAs nanodisks fabricated by using combination of neutral beam etching and atomic hydrogen-assisted molecular beam epitaxy regrowth Citation Details In-Document Search Title:...

  15. Inverse spin Hall effect in Pt/(Ga,Mn)As

    SciTech Connect (OSTI)

    Nakayama, H.; Chen, L.; Chang, H. W.; Ohno, H.; Matsukura, F.

    2015-06-01

    We investigate dc voltages under ferromagnetic resonance in a Pt/(Ga,Mn)As bilayer structure. A part of the observed dc voltage is shown to originate from the inverse spin Hall effect. The sign of the inverse spin Hall voltage is the same as that in Py/Pt bilayer structure, even though the stacking order of ferromagnetic and nonmagnetic layers is opposite to each other. The spin mixing conductance at the Pt/(Ga,Mn)As interface is determined to be of the order of 10{sup 19 }m{sup −2}, which is about ten times greater than that of (Ga,Mn)As/p-GaAs.

  16. Huazhong Science Technology University Yongtai Science Technology...

    Open Energy Info (EERE)

    Huazhong Science Technology University Yongtai Science Technology Co Ltd Jump to: navigation, search Name: Huazhong Science & Technology University Yongtai Science & Technology Co...

  17. Deep level centers and their role in photoconductivity transients of InGaAs/GaAs quantum dot chains

    SciTech Connect (OSTI)

    Kondratenko, S. V. Vakulenko, O. V.; Mazur, Yu. I. Dorogan, V. G.; Marega, E.; Benamara, M.; Ware, M. E.; Salamo, G. J.

    2014-11-21

    The in-plane photoconductivity and photoluminescence are investigated in quantum dot-chain InGaAs/GaAs heterostructures. Different photoconductivity transients resulting from spectrally selecting photoexcitation of InGaAs QDs, GaAs spacers, or EL2 centers were observed. Persistent photoconductivity was observed at 80?K after excitation of electron-hole pairs due to interband transitions in both the InGaAs QDs and the GaAs matrix. Giant optically induced quenching of in-plane conductivity driven by recharging of EL2 centers is observed in the spectral range from 0.83?eV to 1.0?eV. Conductivity loss under photoexcitation is discussed in terms of carrier localization by analogy with carrier distribution in disordered media.

  18. Deep level defects in n-type GaAsBi and GaAs grown at low temperatures

    SciTech Connect (OSTI)

    Mooney, P. M.; Watkins, K. P.; Jiang, Zenan; Basile, A. F.; Lewis, R. B.; Bahrami-Yekta, V.; Masnadi-Shirazi, M.; Beaton, D. A.; Tiedje, T.

    2013-04-07

    Deep level defects in n-type GaAs{sub 1-x}Bi{sub x} having 0 < x < 0.012 and GaAs grown by molecular beam epitaxy (MBE) at substrate temperatures between 300 and 400 Degree-Sign C have been investigated by Deep Level Capacitance Spectroscopy. Incorporating Bi suppresses the formation of an electron trap with activation energy 0.40 eV, thus reducing the total trap concentration in dilute GaAsBi layers by more than a factor of 20 compared to GaAs grown under the same conditions. We find that the dominant traps in dilute GaAsBi layers are defect complexes involving As{sub Ga}, as expected for MBE growth at these temperatures.

  19. Au impact on GaAs epitaxial growth on GaAs (111){sub B} substrates in molecular beam epitaxy

    SciTech Connect (OSTI)

    Liao, Zhi-Ming; Chen, Zhi-Gang; Xu, Hong-Yi; Guo, Ya-Nan; Sun, Wen; Zhang, Zhi; Yang, Lei; Lu, Zhen-Yu; Chen, Ping-Ping; Lu, Wei; Zou, Jin; Centre for Microscopy and Microanalysis, The University of Queensland, St. Lucia, Queensland 4072

    2013-02-11

    GaAs growth behaviour under the presence of Au nanoparticles on GaAs {l_brace}111{r_brace}{sub B} substrate is investigated using electron microscopy. It has been found that, during annealing, enhanced Ga surface diffusion towards Au nanoparticles leads to the GaAs epitaxial growth into {l_brace}113{r_brace}{sub B} faceted triangular pyramids under Au nanoparticles, governed by the thermodynamic growth, while during conventional GaAs growth, growth kinetics dominates, resulting in the flatted triangular pyramids at high temperature and the epitaxial nanowires growth at relatively low temperature. This study provides an insight of Au nanoparticle impact on GaAs growth, which is critical for understanding the formation mechanisms of semiconductor nanowires.

  20. Room-temperature mid-infrared "M"-type GaAsSb/InGaAs quantum well

    Office of Scientific and Technical Information (OSTI)

    lasers on InP substrate (Journal Article) | SciTech Connect Room-temperature mid-infrared "M"-type GaAsSb/InGaAs quantum well lasers on InP substrate Citation Details In-Document Search Title: Room-temperature mid-infrared "M"-type GaAsSb/InGaAs quantum well lasers on InP substrate We have demonstrated experimentally the InP-based "M"-type GaAsSb/InGaAs quantum-well (QW) laser lasing at 2.41 μm at room temperature by optical pumping. The threshold power density

  1. An inverted AlGaAs/GaAs patterned-Ge tunnel junction cascade concentrator solar cell

    SciTech Connect (OSTI)

    Venkatasubramanian, R. )

    1993-01-01

    This report describes work to develop inverted-grown Al[sub 0.34]Ga[sub 0.66]As/GaAs cascades. Several significant developments are reported on as follows: (1) The AM1.5 1-sun total-area efficiency of the top Al[sub 0.34]Ga[sub 0.66]As cell for the cascade was improved from 11.3% to 13.2% (NREL measurement [total-area]). (2) The cycled'' organometallic vapor phase epitaxy growth (OMVPE) was studied in detail utilizing a combination of characterization techniques including Hall-data, photoluminescence, and secondary ion mass spectroscopy. (3) A technique called eutectic-metal-bonding (EMB) was developed by strain-free mounting of thin GaAs-AlGaAs films (based on lattice-matched growth on Ge substrates and selective plasma etching of Ge substrates) onto Si carrier substrates. Minority-carrier lifetime in an EMB GaAs double-heterostructure was measured as high as 103 nsec, the highest lifetime report for a freestanding GaAs thin film. (4) A thin-film, inverted-grown GaAs cell with a 1-sun AM1.5 active-area efficiency of 20.3% was obtained. This cell was eutectic-metal-bonded onto Si. (5) A thin-film inverted-grown, Al[sub 0.34]Ga[sub 0.66]As/GaAs cascade with AM1.5 efficiency of 19.9% and 21% at 1-sun and 7-suns, respectively, was obtained. This represents an important milestone in the development of an AlGaAs/GaAs cascade by OMVPE utilizing a tunnel interconnect and demonstrates a proof-of-concept for the inverted-growth approach.

  2. NREL: Technology Deployment - Technology Acceleration

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

    Technology Acceleration NREL offers technology-specific assistance to federal and private industry to help address market barriers to sustainable energy technologies. Learn more about NREL's work in the following areas: Biopower and Waste-to-Energy Biopower and Waste-to-Energy Buildings Buildings Fuels, Vehicles, & Transportation Fuels, Vehicles, and Transportation Microgrid Design Microgrid Design Solar Solar Wind Wind Contact Us For more information on NREL's market transformation work,

  3. Thermally activated technologies: Technology Roadmap

    SciTech Connect (OSTI)

    None, None

    2003-05-01

    The purpose of this Technology Roadmap is to outline a set of actions for government and industry to develop thermally activated technologies for converting Americas wasted heat resources into a reservoir of pollution-free energy for electric power, heating, cooling, refrigeration, and humidity control. Fuel flexibility is important. The actions also cover thermally activated technologies that use fossil fuels, biomass, and ultimately hydrogen, along with waste heat.

  4. Technology Assessment

    Energy Savers [EERE]

    Roll to Roll (R2R) Processing 1 Technology Assessment 2 3 Contents 4 1. Introduction to the Technology/System ............................................................................................... 2 5 1.1. Introduction to R2R Processing..................................................................................................... 2 6 1.2. R2R Processing Mechanisms ......................................................................................................... 3 7 2.

  5. DC characteristics of OMVPE-grown N-p-n InGaP/InGaAsN DHBTs

    SciTech Connect (OSTI)

    Li, N.Y.; Chang, P.C.; Baca, A.G.; Xie, X.M.; Sharps, P.R.; Hou, H.Q.

    2000-01-04

    The authors demonstrate, for the first time, a functional N-p-n heterojunction bipolar transistor using a novel material, InGaAsN, with a bandgap energy of 1.2eV as the p-type base layer. A 300{angstrom}-thick In{sub x}Ga{sub 1-x}As graded layer was introduced to reduce the conduction band offset at the p-type InGaAsN base and n-type GaAs collector junction. For an emitter size of 500 {mu}m{sup 2}, a peak current gain of 5.3 has been achieved.

  6. SR0005

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

    Program (EMSP) National Workshop in Atlanta, GA on April 24-27 at the Westin Peachtree Plaza. Hosted by DOE's Office of Environmental Management, Office of Science, Idaho...

  7. app_d

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

    31 DOE/EIS-0287 Idaho HLW & FD EIS Document 23, Department of Health & Human Services (Kenneth W. Holt), Atlanta, GA Page 10 of 21 Document 23, Department of Health & Human Services (Kenneth W. Holt), Atlanta, GA Page 11 of 21 - New Information - DOE/EIS-0287 D-32 Appendix D Document 23, Department of Health & Human Services (Kenneth W. Holt), Atlanta, GA Page 12 of 21 Document 23, Department of Health & Human Services (Kenneth W. Holt), Atlanta, GA Page 13 of 21 - New

  8. A high-resolution imaging X-ray crystal spectrometer for intense...

    Office of Scientific and Technical Information (OSTI)

    Conference Resource Relation: Conference: Presented at: 20th Topical Conference on High-Temperature Plasma Diagnostics Conference, Atlanta, GA, United States, Jun 01 - Jun 05, 2014...

  9. System for Calibrating the Energy-Dependent Response of an Elliptical...

    Office of Scientific and Technical Information (OSTI)

    Topical Conference on High Temperature Plasma Diagnostics, Atlanta, GA, United States, Jun 01 - Jun 05, 2014 Research Org: Lawrence Livermore National Laboratory (LLNL),...

  10. Development of a TIM-based, flexible, broadband two-crystal spectromet...

    Office of Scientific and Technical Information (OSTI)

    Presented at: High Temperature Plasma Diagnostics, Atlanta, GA, United States, Jun 01 - Jun 05, 2014 Research Org: Lawrence Livermore National Laboratory (LLNL),...

  11. Coarse-grained Energy Modeling of Rollback/Recovery Mechanisms...

    Office of Scientific and Technical Information (OSTI)

    Resource Type: Conference Resource Relation: Conference: Fault Tolerance for HPC at eXtreme Scale (FTXS) Workshop held June 23-24, 2014 in Atlanta, GA.; Related...

  12. QER- Comment of Stephen Arthur 1

    Broader source: Energy.gov [DOE]

    Good morning, I simply was curious if the Atlanta, GA meeting on Business/Economic Development was still on schedule and going to take place?

  13. 2015 University Turbine Systems Research Workshop

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

    University Turbine Systems Research Workshop November 3-5, 2015 Accommodations Georgian Terrace Hotel 659 Peachtree Street, NE Atlanta, GA 30308 The Georgian Terrace Hotel will be...

  14. Benchmarking & Transparency Policy and Program Impact Evaluation...

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

    ... Therefore, more advanced- and generally more expensive -evaluation methods are included in ... Montgomery County, MD; San Francisco; Cambridge, MA; Chicago; Portland, OR; Atlanta, GA; ...

  15. Industrial Feedstock Flexibility Workshop Results

    SciTech Connect (OSTI)

    Ozokwelu, Dickson; Margolis, Nancy; Justiniano, Mauricio; Monfort, Joe; Brueske, Sabine; Sabouni, Ridah

    2009-08-01

    This report (PDF 649 KB) summarizes the results of the 2009 Industrial Feedstock Flexibility Workshop, which took place in Atlanta, GA on August 19-20, 2009.

  16. Search for: All records | SciTech Connect

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

    Atlanta, GA (United States) Atmospheric System Research Bartlesville Project Office, OK (United States) Battelle Memorial Institute (United States) Bechtel Hanford Inc. (BHI),...

  17. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Regional Office, Atlanta, GA (United States) Atmospheric System Research Bartlesville Project Office, OK (United States) Battelle Memorial Institute (United States) Bechtel...

  18. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Atlanta, GA (United States) Atmospheric System Research Bartlesville Project Office, OK ... We consider the R-axion which has relatively heavy mass in order to complement our ...

  19. Microfabricated Optical Compressive Load Sensors (Conference...

    Office of Scientific and Technical Information (OSTI)

    W-7405-ENG-48 Resource Type: Conference Resource Relation: Conference: Presented at: IEEE Sensors 2007, Atlanta, GA, United States, Oct 28 - Oct 31, 2007 Research Org: Lawrence...

  20. About Us - SRSCRO

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

    GA and Aiken, SC and is less than three hours drive from Atlanta, Charlotte, the Blue Ridge Mountains and the Atlantic Ocean beaches of Savannah, Charleston, Myrtle Beach...

  1. Microfabricated Optical Compressive Load Sensors (Conference...

    Office of Scientific and Technical Information (OSTI)

    DOE Contract Number: W-7405-ENG-48 Resource Type: Conference Resource Relation: Conference: Presented at: IEEE Sensors 2007, Atlanta, GA, United States, Oct 28 - Oct 31, 2007 ...

  2. A new pre-processing method for scanning X-ray microdiffraction...

    Office of Scientific and Technical Information (OSTI)

    Resource Type: Conference Resource Relation: Conference: 2015 IEEE Biomedical Circuits and Systems Conference (BioCAS);Oct. 22-24, 205;Atlanta, GA Publisher: 2015 IEEE Biomedical ...

  3. Near-infrared electroluminescence and photo detection in InGaAs p-i-n microdisks grown by selective area growth on silicon

    SciTech Connect (OSTI)

    Kjellman, Jon yvind; Sugiyama, Masakazu; Nakano, Yoshiaki

    2014-06-16

    Microselective-area growth of p-i-n InGaAs disks on (111) silicon by metalorganic chemical vapor deposition is a promising technology for III/V-on-Si integration. As a proof-of-concept, room-temperature electroluminescence is reported from ensembles of p-i-n InGaAs-on-Si micro-disks. The observed spectrum shows peak luminescence at 1.78??m with a local maxima at 1.65??m. The disks are also shown to generate a measurable photo current when illuminated by infrared light with less energy than the silicon bandgap energy. This makes these InGaAs-on-Si disks a promising technology for monolithic integration of light sources and detectors with silicon photonics and complementary metal-oxide-semiconductor electronics for optical communication, sensing, and imaging.

  4. A monolithic white LED with an active region based on InGaN QWs separated by short-period InGaN/GaN superlattices

    SciTech Connect (OSTI)

    Tsatsulnikov, A. F. Lundin, W. V.; Sakharov, A. V.; Zavarin, E. E.; Usov, S. O.; Nikolaev, A. E.; Kryzhanovskaya, N. V.; Synitsin, M. A.; Sizov, V. S.; Zakgeim, A. L.; Mizerov, M. N.

    2010-06-15

    A new approach to development of effective monolithic white-light emitters is described based on using a short-period InGaN/GaN superlattice as a barrier layer in the active region of LED structures between InGaN quantum wells emitting in the blue and yellow-green spectral ranges. The optical properties of structures of this kind have been studied, and it is demonstrated that the use of such a superlattice makes it possible to obtain effective emission from the active region.

  5. DOE Zero Energy Ready Home Case Study: Imery Group, Proud Green Home, Serenbe GA

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

    Home Serenbe, GA DOE ZERO ENERGY READY HOME CASE STUDY DOE Zero Energy Ready Home builders are in the top 1% of builders in the country meeting the extraordinary levels of excellence and quality specified by the U.S. Department of Energy. Every DOE Zero Energy Ready Home starts with ENERGY STAR for Homes Version 3 for an energy-efficient home built on a solid foundation of building science research. Then, even more advanced technologies are designed in for a home that goes above and beyond

  6. DOE Zero Ready Home Case Study: The Imery Group, Proud Green Home, Serenbe, GA

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

    Home Serenbe, GA DOE ZERO ENERGY READY HOME(tm) The U.S. Department of Energy invites home builders across the country to meet the extraordinary levels of excellence and quality specified in DOE's Zero Energy Ready Home program (formerly known as Challenge Home). Every DOE Zero Energy Ready Home starts with ENERGY STAR Certified Homes Version 3.0 for an energy-efficient home built on a solid foundation of building science research. Advanced technologies are designed in to give you superior

  7. Long-wavelength shift and enhanced room temperature photoluminescence efficiency in GaAsSb/InGaAs/GaAs-based heterostructures emitting in the spectral range of 1.01.2??m due to increased charge carrier's localization

    SciTech Connect (OSTI)

    Kryzhkov, D. I. Yablonsky, A. N.; Morozov, S. V.; Aleshkin, V. Ya.; Krasilnik, Z. F.; Zvonkov, B. N.; Vikhrova, O. V.

    2014-11-28

    In this work, a study of the photoluminescence (PL) temperature dependence in quantum well GaAs/GaAsSb and double quantum well InGaAs/GaAsSb/GaAs heterostructures grown by metalorganic chemical vapor deposition with different parameters of GaAsSb and InGaAs layers has been performed. It has been demonstrated that in double quantum well InGaAs/GaAsSb/GaAs heterostructures, a significant shift of the PL peak to a longer-wavelength region (up to 1.2??m) and a considerable reduction in the PL thermal quenching in comparison with GaAs/GaAsSb structures can be obtained due to better localization of charge carriers in the double quantum well. For InGaAs/GaAsSb/GaAs heterostructures, an additional channel of radiative recombination with participation of the excited energy states in the quantum well, competing with the main ground-state radiative transition, has been revealed.

  8. High-Efficiency Non-Polar GaN-Based LEDs

    SciTech Connect (OSTI)

    Paul Fini

    2010-11-30

    Inlustra Technologies with subcontractor U.C. Santa Barbara conducted a project with the principle goal of demonstrating high internal quantum efficiency blue (430 nm) and green (540nm) light emitting diodes (LEDs) on low-defect density non-polar GaN wafers. Inlustra pursued the fabrication of smooth thick a-plane and m-plane GaN films, as well as defect reduction techniques such as lateral epitaxial overgrowth (LEO) to uniformly lower dislocation density in these films. Limited free-standing wafers were produced as well. By the end of the reporting period, Inlustra had met its milestone of dislocation reduction to < 5 x 10{sup 6} cm{sup -2}. Stacking faults were still present in appreciable density ({approx} 1 x 10{sup 5} cm{sup -1}), but were not the primary focus of defect reduction since there have been no published studies establishing their detrimental effects on LED performance. Inlustra's LEO progress built a solid foundation upon which further commercial development of GaN substrates will occur. UCSB encountered multiple delays in its LED growth and fabrication efforts due to unavoidable facilities outages imposed by ongoing construction in an area adjacent to the metalorganic chemical vapor deposition (MOCVD) laboratory. This, combined with the large amount of ab initio optimization required for the MOCVD system used during the project, resulted in unsatisfactory LED progress. Although numerous blue-green photoluminescence results were obtained, only a few LED structures exhibited electroluminescence at appreciable levels. UCSB also conducting extensive modeling (led by Prof. Van de Walle) on the problem of non-radiative Auger recombination in GaN-based LED structures, which has been posited to contribute to LED efficiency 'droop' at elevated current density. Unlike previous modeling efforts, UCSB's approach was truly a first-principles ab initio methodology. Building on solid numerical foundations, the Auger recombination rates of In{sub x}Ga{sub 1-x}N alloys were calculated from first-principles density-functional and many-body-perturbation theory. The differing mechanisms of inter- and intra-band recombination were found to affect different parts of the emission spectrum. In the blue to green spectral region and at room temperature the Auger coefficient was calculated to be as large as 2 x 10{sup -30} cm{sup 6} s{sup -1}; in the infrared it is even larger. These results indicated that Auger recombination may be responsible for the loss of quantum efficiency that affects InGaN-based light emitters, whether on non-polar or polar crystal planes.

  9. Technology Commercialization Showcase 2008 Vehicle Technologies Program

    SciTech Connect (OSTI)

    Davis, Patrick B.

    2009-06-19

    Presentation illustrating various technology commercialization opportunities and unexploited investment gaps for the Vehicle Technologies Program.

  10. Photoeffects in WO{sub 3}/GaAs electrode

    SciTech Connect (OSTI)

    Yoon, K.H.; Lee, J.W.; Cho, Y.S.; Kang, D.H.

    1996-12-01

    Photoeffects of a {ital p}-type GaAs coated with WO{sub 3} thin film have been investigated as a function of film thickness and photoresponse transients of the WO{sub 3}/GaAs electrode were studied. Also, these results were compared to those for a single {ital p}-type GaAs electrode. The photocurrent of the WO{sub 3}/GaAs electrode depended on the film thickness of the WO{sub 3}, showing an optimum photon efficiency for specimens of 800 A thickness. This is due to the existence of an effective interface state within the band gap which reduces trapping of carriers and facilitates carrier movement. For an 800-A-thick WO{sub 3} thin film deposited {ital p}-GaAs photoelectrode, the photogenerated electrons were found to move to an electrolyte at a higher positive onset potential compared with that of single {ital p}-type GaAs, which was confirmed as a result of transient behavior. {ital I}{endash}{ital V} and {ital C}{endash}{ital V} characteristics of the WO{sub 3}/GaAs electrode were also compared with those of a single {ital p}-type GaAs electrode. {copyright} {ital 1996 American Institute of Physics.}

  11. A Computational Study of the Aerodynamics and Aeroacoustics of a Flatback Airfoil Using Hybrid RANS-LES

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

    Computational Study of the Aerodynamics and Aeroacoustics of a Flatback Airfoil Using Hybrid RANS-LES Christopher Stone ∗ Computational Science & Engineering, Athens, GA, 30606, USA Matthew Barone † Sandia National Laboratories, Albuquerque, NM, 87185-1124, USA C. Eric Lynch ‡ and Marilyn J. Smith § Georgia Institute of Technology, Atlanta, Georgia, 30332-0150, USA This work compares the aerodynamic and aeroacoustic predictions for flatback air- foil geometries obtained by applying

  12. Paper Title (use style: paper title)

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

    Interconnection Risk Analysis through Distribution System Impact Signatures and Feeder Zones Matthew J. Reno, Kyle Coogan, Santiago Grijalva School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta, GA, USA Robert J. Broderick, Jimmy E. Quiroz Photovoltaics and Distributed Grid Integration Sandia National Laboratories Albuquerque, NM, USA Abstract- High penetrations of PV on the distribution system can impact the operation of the grid and may require interconnection

  13. AWEA WINDPOWER 2012 Conference and Exhibition; Scientific Track Paper

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

    AWEA WINDPOWER 2012 Conference and Exhibition; Scientific Track Paper Atlanta, GA; June 3-6, 2012 Challenges and Opportunities in Large Offshore Rotor Development: Sandia 100-meter Blade Research D. Todd Griffith, 1 Brian R. Resor, 2 and Thomas D. Ashwill 3 Sandia National Laboratories, Albuquerque, New Mexico 87185 Sandia National Laboratories' (SNL) Wind & Water Power Technologies Department, as part of its ongoing R&D efforts, creates and evaluates innovative large blade concepts for

  14. Workshop 2: Advanced HVAC&R Research Effort

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

    ASHRAE Headquarters, Atlanta, GA 10:00AM - 3:00PM December 8, 2015 DOE Building Technologies Office: Advanced HVAC&R Research Effort Workshop on Technical Focus and Structure 1 ©2015 Navigant Consulting, Inc. Confidential and proprietary. Do not distribute or copy. Welcome » Introductions and Logistics Navigant, on behalf of the United States Department of Energy, welcomes you to this workshop on an Advanced HVAC&R Research Effort Introductions and Logistics * Timing * Restrooms *

  15. Race to Zero 2015 Analysis Excellence Award Presentations | Department of

    Energy Savers [EERE]

    Energy Analysis Excellence Award Presentations Race to Zero 2015 Analysis Excellence Award Presentations View the presentations for the 2015 Race to Zero Student Design Competition Analysis Excellence Award winners. HouZe GT - The Zeroes Georgia Institute of Technology, Atlanta, GA The Corner House - [DAS]Haus Ryerson University, Toronto, Ontario, Canada The Serrano House - Negawatt Team University of California, Berkeley, Berkeley, CA The TownHauZ - Invent the Future Virginia Tech,

  16. DOE Recognizes Green Power Network Leaders | Department of Energy

    Office of Environmental Management (EM)

    Recognizes Green Power Network Leaders DOE Recognizes Green Power Network Leaders September 14, 2009 - 12:00am Addthis ATLANTA, GA - U.S. Department of Energy Secretary Steven Chu today recognized five leading organizations for advancing the development and use of green energy. The five organizations are being recognized for their exceptional achievements in supporting increased market deployment of renewable energy technologies through green power programs. These organizations underscore the

  17. Growth of GaN@InGaN Core-Shell and Au-GaN Hybrid Nanostructures for Energy Applications

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

    Kuykendall, Tevye; Aloni, Shaul; Jen-La Plante, Ilan; Mokari, Taleb

    2009-01-01

    We demonstrated a method to control the bandgap energy of GaN nanowires by forming GaN@InGaN core-shell hybrid structures using metal organic chemical vapor deposition (MOCVD). Furthermore, we show the growth of Au nanoparticles on the surface of GaN nanowires in solution at room temperature. The work shown here is a first step toward engineering properties that are crucial for the rational design and synthesis of a new class of photocatalytic materials. The hybrid structures were characterized by various techniques, including photoluminescence (PL), energy dispersive x-ray spectroscopy (EDS), transmission and scanning electron microscopy (TEM and SEM), and x-ray diffraction (XRD).

  18. Elastic properties of Pu metal and Pu-Ga alloys

    SciTech Connect (OSTI)

    Soderlind, P; Landa, A; Klepeis, J E; Suzuki, Y; Migliori, A

    2010-01-05

    We present elastic properties, theoretical and experimental, of Pu metal and Pu-Ga ({delta}) alloys together with ab initio equilibrium equation-of-state for these systems. For the theoretical treatment we employ density-functional theory in conjunction with spin-orbit coupling and orbital polarization for the metal and coherent-potential approximation for the alloys. Pu and Pu-Ga alloys are also investigated experimentally using resonant ultrasound spectroscopy. We show that orbital correlations become more important proceeding from {alpha} {yields} {beta} {yields} {gamma} plutonium, thus suggesting increasing f-electron correlation (localization). For the {delta}-Pu-Ga alloys we find a softening with larger Ga content, i.e., atomic volume, bulk modulus, and elastic constants, suggest a weakened chemical bonding with addition of Ga. Our measurements confirm qualitatively the theory but uncertainties remain when comparing the model with experiments.

  19. General Atomics (GA) Fusion News: A New Spin on Understanding Plasma

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

    Confinement | Princeton Plasma Physics Lab General Atomics (GA) Fusion News: A New Spin on Understanding Plasma Confinement American Fusion News Category: General Atomics (GA) Link: General Atomics (GA) Fusion News: A New Spin on Understanding Plasma Confinement

  20. Room temperature spin transport in undoped (110) GaAs/AlGaAs quantum wells

    SciTech Connect (OSTI)

    Yokota, Nobuhide Aoshima, Yohei; Ikeda, Kazuhiro; Kawaguchi, Hitoshi

    2014-02-17

    We are reporting on our first observation of a micrometer-order electron spin transport in a (110) GaAs/AlGaAs multiple quantum well (QW) at room temperature using a space- and time-resolved Kerr rotation technique. A 37-μm transport was observed within an electron spin lifetime of 1.2 ns at room temperature when using an in-plane electric field of 1.75 kV/cm. The spatio-temporal profiles of electron spins were well reproduced by the spin drift-diffusion equations coupled with the Poisson equation, supporting the validity of the measurement. The results suggest that (110) QWs are useful as a spin transport layer for semiconductor spintronic devices operating at room temperature.

  1. Sidewall passivation for InGaN/GaN nanopillar light emitting diodes

    SciTech Connect (OSTI)

    Choi, Won Hyuck; Abraham, Michael; Yu, Shih-Ying [Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); You, Guanjun; Liu, Jie; Wang, Li; Xu, Jian, E-mail: jianxu@engr.psu.edu [Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Mohney, Suzanne E., E-mail: mohney@ems.psu.edu [Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

    2014-07-07

    We studied the effect of sidewall passivation on InGaN/GaN multiquantum well-based nanopillar light emitting diode (LED) performance. In this research, the effects of varying etch rate, KOH treatment, and sulfur passivation were studied for reducing nanopillar sidewall damage and improving device efficiency. Nanopillars prepared under optimal etching conditions showed higher photoluminescence intensity compared with starting planar epilayers. Furthermore, nanopillar LEDs with and without sulfur passivation were compared through electrical and optical characterization. Suppressed leakage current under reverse bias and four times higher electroluminescence (EL) intensity were observed for passivated nanopillar LEDs compared with unpassivated nanopillar LEDs. The suppressed leakage current and EL intensity enhancement reflect the reduction of non-radiative recombination at the nanopillar sidewalls. In addition, the effect of sulfur passivation was found to be very stable, and further insight into its mechanism was gained through transmission electron microscopy.

  2. Evaluation of the two-photon absorption characteristics of GaSb/GaAs quantum rings

    SciTech Connect (OSTI)

    Wagener, M. C.; Botha, J. R.; Carrington, P. J.; Krier, A.

    2014-07-28

    The optical parameters describing the sub-bandgap response of GaSb/GaAs quantum rings solar cells have been obtained from photocurrent measurements using a modulated pseudo-monochromatic light source in combination with a second, continuous photo-filling source. By controlling the charge state of the quantum rings, the photoemission cross-sections describing the two-photon sub-bandgap transitions could be determined independently. Temperature dependent photo-response measurements also revealed that the barrier for thermal hole emission from the quantum rings is significantly below the quantum ring localisation energy. The temperature dependence of the sub-bandgap photo-response of the solar cell is also described in terms of the photo- and thermal-emission characteristics of the quantum rings.

  3. Large linear magnetoresistance in a GaAs/AlGaAs heterostructure

    SciTech Connect (OSTI)

    Aamir, Mohammed Ali, E-mail: aamir@physics.iisc.ernet.in; Goswami, Srijit, E-mail: aamir@physics.iisc.ernet.in; Ghosh, Arindam [Department of Physics, Indian Institute of Science, Bangalore 560 012 (India); Baenninger, Matthias; Farrer, Ian; Ritchie, David A. [Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Tripathi, Vikram [Department of Theoretical Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India); Pepper, Michael [Department of Electrical and Electronic Engineering, University College, London WC1E 7JE (United Kingdom)

    2013-12-04

    We report non-saturating linear magnetoresistance (MR) in a two-dimensional electron system (2DES) at a GaAs/AlGaAs heterointerface in the strongly insulating regime. We achieve this by driving the gate voltage below the pinch-off point of the device and operating it in the non-equilibrium regime with high source-drain bias. Remarkably, the magnitude of MR is as large as 500% per Tesla with respect to resistance at zero magnetic field, thus dwarfing most non-magnetic materials which exhibit this linearity. Its primary advantage over most other materials is that both linearity and the enormous magnitude are retained over a broad temperature range (0.3 K to 10 K), thus making it an attractive candidate for cryogenic sensor applications.

  4. Tag: technology

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

    Tags

    technology<...

  5. Technology Validation

    Broader source: Energy.gov [DOE]

    To reduce solar technology risks, DOE and its partners evaluate the performance and reliability of novel photovoltaic (PV) hardware and systems through laboratory and field testing. The focus of...

  6. Optical properties of multi-stacked InGaAs/GaNAs quantum dot solar cell fabricated on GaAs (311)B substrate

    SciTech Connect (OSTI)

    Shoji, Yasushi; Akimoto, Katsuhiro; Okada, Yoshitaka

    2012-09-15

    Quantum dot solar cells (QDSCs) comprised of 10 stacked pairs of strain-compensated InGaAs/GaNAs QD structure have been fabricated by atomic hydrogen-assisted molecular beam epitaxy. A homogeneous and high-density QD array structure with improved in-plane ordering and total density of {approx}10{sup 12} cm{sup -2} has been achieved on GaAs (311)B grown at 460 Degree-Sign C after stacking. The external quantum efficiency (EQE) of InGaAs/GaNAs QDSC increases in the longer wavelength range due to additive contribution from QD layers inserted in the intrinsic region. The short-circuit current density measured for QDSC is 17.2 mA/cm{sup 2} compared to 14.8 mA/cm{sup 2} of GaAs reference cell. Further, an increase in EQE due to photocurrent production by 2-step photon absorption has been observed at room temperature though it is still small at around 0.1%.

  7. Transport properties of InGaAs/GaAs Heterostructures with {delta}-doped quantum wells

    SciTech Connect (OSTI)

    Baidus, N. V.; Vainberg, V. V.; Zvonkov, B. N.; Pylypchuk, A. S. Poroshin, V. N.; Sarbey, O. G.

    2012-05-15

    The lateral transport of electrons in single- and double-well pseudomorphic GaAs/n-InGaAs/GaAs heterostructures with quantum wells 50-100 meV deep and impurity {delta}-layers in the wells, with concentrations in the range 10{sup 11} < N{sub s} < 10{sup 12} cm{sup -2}, has been investigated. Single-well structures with a doped well at the center exhibit a nonmonotonic temperature dependence of the Hall coefficient and an increase in low-temperature electron mobility with an increase in the impurity concentration. The results obtained indicate that the impurity-band electron states play an important role in the conductivity of these structures. Involvement of the impurity band also allows to explain adequately the characteristics of the conductivity of double-well structures; in contrast to single-well structures, band bending caused by asymmetric doping is of great importance. The numerical calculations of conductivity within the model under consideration confirm these suggestions.

  8. Germanium subcells for multijunction GaInP/GaInAs/Ge solar cells

    SciTech Connect (OSTI)

    Kalyuzhnyy, N. A.; Gudovskikh, A. S.; Evstropov, V. V.; Lantratov, V. M.; Mintairov, S. A.; Timoshina, N. Kh.; Shvarts, M. Z.; Andreev, V. M.

    2010-11-15

    Photovoltaic converters based on n-GaInP/n-p-Ge heterostructures grown by the OMVPE under different conditions of formation of the p-n junction are studied. The heterostructures are intended for use as narrow-gap subcells of the GaInP/GaInAs/Ge three-junction solar cells. It is shown that, in Ge p-tn junctions, along with the diffusion mechanism, the tunneling mechanism of the current flow exists; therefore, the two-diode electrical equivalent circuit of the Ge p-n junction is used. The diode parameters are determined for both mechanisms from the analysis of both dark and 'light' current-voltage dependences. It is shown that the elimination of the component of the tunneling current allows one to increase the efficiency of the Ge subcell by {approx}1% with conversion of nonconcentrated solar radiation. The influence of the tunneling current on the efficiency of the Ge-based devices can be in practice reduced to zero at photogenerated current density of {approx}1.5 A/cm{sup 2} due to the use of the concentrated solar radiation.

  9. Structural and emission properties of InGaAs/GaAs quantum dots emitting at 1.3??m

    SciTech Connect (OSTI)

    Goldmann, Elias Jahnke, Frank; Paul, Matthias; Kettler, Jan; Jetter, Michael; Michler, Peter; Krause, Florian F.; Mller, Knut; Mehrtens, Thorsten; Rosenauer, Andreas

    2014-10-13

    A combined experimental and theoretical study of InGaAs/GaAs quantum dots (QDs) emitting at 1.3??m under the influence of a strain-reducing InGaAs quantum well is presented. We demonstrate a red shift of 2040?nm observed in photoluminescence spectra due to the quantum well. The InGaAs/GaAs QDs grown by metal organic vapor phase epitaxy show a bimodal height distribution (1?nm and 5?nm) and indium concentrations up to 90%. The emission properties are explained with combined tight-binding and configuration-interaction calculations of the emission wavelengths in conjunction with high-resolution scanning transmission electron microscopy investigations of QD geometry and indium concentrations in the QDs, which directly enter the calculations. QD geometries and concentration gradients representative for the ensemble are identified.

  10. Technology Roadmap Analysis 2013: Assessing Automotive Technology...

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

    Roadmap Analysis 2013: Assessing Automotive Technology R&D Relevant to DOE Power Electronics Cost Targets Technology Roadmap Analysis 2013: Assessing Automotive Technology R&D ...

  11. National Energy Technology Laboratory Technology Marketing Summaries...

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

    National Energy Technology Laboratory Technology Marketing Summaries Here you'll find marketing summaries for technologies available for licensing from the National Energy...

  12. Design of a GaAs/Ge solar array for unmanned aerial vehicles

    SciTech Connect (OSTI)

    Scheiman, D.A.; Colozza, A.J.; Brinker, D.J.; Bents, D.J.

    1994-12-31

    Unmanned Aerial Vehicles (UAV) are being proposed for many applications including surveillance, mapping and atmospheric studies. These applications require a lightweight, low speed, medium to long duration airplane. Due to the weight, speed, and altitude constraints imposed on such aircraft, solar array generated electric power is a viable alternative to air-breathing engines. Development of such aircraft is currently being funded under the Environmental Research Aircraft and Sensor Technology (ERAST) program. NASA Lewis Research Center (LeRC) is currently building a Solar Electric Airplane to demonstrate UAV technology. This aircraft utilizes high efficiency Applied Solar Energy Corporation (ASEC) GaAs/Ge space solar cells. The cells have been provided by the Air Force through the ManTech Office. Expected completion of the plane is early 1995, with the airplane currently undergoing flight testing using battery power.

  13. Design of a GaAs/Ge solar array for unmanned aerial vehicles

    SciTech Connect (OSTI)

    Scheiman, D.A.; Brinker, D.J.; Bents, D.J.; Colozza, A.J.

    1995-03-01

    Unmanned Aerial Vehicles (UAV) are being proposed for many applications including surveillance, mapping and atmospheric studies. These applications require a lightweight, low speed, medium to long duration airplane. Due to the weight, speed, and altitude constraints imposed on such aircraft, solar array generated electric power is a viable alternative to air-breathing engines. Development of such aircraft is currently being funded under the Environmental Research Aircraft and Sensor Technology (ERAST) program. NASA Lewis Research Center (LeRC) is currently building a Solar Electric Airplane to demonstrate UAV technology. This aircraft utilizes high efficiency Applied Solar Energy Corporation (ASEC) GaAs/Ge space solar cells. The cells have been provided by the Air Force through the ManTech Office. Expected completion of the plane is early 1995, with the airplane currently undergoing flight testing using battery power.

  14. 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.

  15. Characterization of Zns-GaP Naon-composites

    SciTech Connect (OSTI)

    Todd, V.

    1993-12-09

    It proved possible to produce consistent, high-quality nanocrystalline ZnS powders with grain sizes as small as 8 nm. These powders are nano-porous and are readily impregnated with GaP precursor, although inconsistently. Both crystal structure and small grain size of the ZnS can be maintained through the use of GaP. Heat treatment of the impregnated powders results in a ZnS-GaP composite structure where the grain sizes of the phases are on the order of 10--20 nm. Conventional powder processing should be able to produce optically dense ceramic compacts with improved mechanical properties and suitable IR transmission.

  16. Outdoor Testing of GaInP2/GaAs Tandem Cells with Top Cell Thickness Varied

    SciTech Connect (OSTI)

    McMahon, W. E.; Emergy, K. E.; Friedman, D. J.; Ottoson, L.; Young, M. S.; Ward, J. S.; Kramer, C. M.; Duda, A.; Kurtz, S.

    2005-08-01

    In this study, we measure the performance of GaInP2/GaAs tandem cells under direct beam sunlight outdoors in order to quantify their sensitivity to both spectral variation and GaInP2 top-cell thickness. A set of cells with five different top-cell thicknesses was mounted on a two-axis tracker with the incident sunlight collimated to exclude all except the direct beam. Current-voltage (I-V) curves were taken throughout the course of several days, along with measurements of the direct solar spectrum. Our two major conclusions are: (1) GaInP2/GaAs tandem cells designed for either the ASTM G-173 direct (G-173D) spectrum or the "air mass 1.5 global" (AM1.5G) spectrum perform the best, and (2) cells can be characterized indoors and modeled using outdoor spectra with the same result. These results are equally valid for GaInP2/GaAs/Ge triple-junction cells.

  17. Local Structures and Interface Morphology of InGaAsN Thin Films Grown on GaAs

    SciTech Connect (OSTI)

    Allerman, A.A.; Chen, J.G.; Geisz, J.F.; Huang, S.; Hulbert, S.L.; Jones, E.D.; Kao, Y.H.; Kurtz, S.; Kurtz, S.R.; Olson, J.M.; Soo, Y.L.

    1999-02-23

    The compound semiconductor system InGaAsN exhibits many intriguing properties which are particularly useful for the development of innovative high efficiency thin film solar cells and long wavelength lasers. The bandgap in these semiconductors can be varied by controlling the content of N and In and the thin films can yet be lattice-matched to GaAs. In the present work, x-ray absorption fine structure (XAFS) and grazing incidence x-ray scattering (GIXS) techniques have been employed to probe the local environment surrounding both N and In atoms as well as the interface morphology of InGaAsN thin films epitaxially grown on GaAs. The soft x-ray XAFS results around nitrogen K-edge reveal that N is in the sp{sup 3} hybridized bonding configuration in InGaAsN and GaAsN, suggesting that N impurities most likely substitute for As sites in these two compounds. The results of In K-edge XAFS suggest a possible trend of a slightly larger coordination number of As nearest neighbors around In atoms in InGaAsN samples with a narrower bandgap whereas the In-As interatomic distance remains practically the same as in InAs within the experimental uncertainties. These results combined suggest that N-substitution of the As sites plays an important role of bandgap-narrowing while in the meantime counteracting the compressive strain caused by In-doping. Grazing incidence x-ray scattering (GIXS) experiments verify that InGaAsN thin films can indeed form very smooth interfaces with GaAs yielding an average interfacial roughness of 5-20{angstrom}.

  18. Manufacturing technologies

    SciTech Connect (OSTI)

    1995-09-01

    The Manufacturing Technologies Center is an integral part of Sandia National Laboratories, a multiprogram engineering and science laboratory, operated for the Department of Energy (DOE) with major facilities at Albuquerque, New Mexico, and Livermore, California. Our Center is at the core of Sandia`s Advanced Manufacturing effort which spans the entire product realization process.

  19. Plasma technology

    SciTech Connect (OSTI)

    Herlitz, H.G.

    1986-11-01

    This paper describes the uses of plasma technology for the thermal destruction of hazardous wastes such as PCBs, dioxins, hydrocarbons, military chemicals and biological materials; for metals recovery from steel making dusts. One advantage of the process is that destruction of wastes can be carried out on site. Systems in several countries use the excess thermal energy for district heating.

  20. (Environmental technology)

    SciTech Connect (OSTI)

    Boston, H.L.

    1990-10-12

    The traveler participated in a conference on environmental technology in Paris, sponsored by the US Embassy-Paris, US Environmental Protection Agency (EPA), the French Environmental Ministry, and others. The traveler sat on a panel for environmental aspects of energy technology and made a presentation on the potential contributions of Oak Ridge National Laboratory (ORNL) to a planned French-American Environmental Technologies Institute in Chattanooga, Tennessee, and Evry, France. This institute would provide opportunities for international cooperation on environmental issues and technology transfer related to environmental protection, monitoring, and restoration at US Department of Energy (DOE) facilities. The traveler also attended the Fourth International Conference on Environmental Contamination in Barcelona. Conference topics included environmental chemistry, land disposal of wastes, treatment of toxic wastes, micropollutants, trace organics, artificial radionuclides in the environment, and the use biomonitoring and biosystems for environmental assessment. The traveler presented a paper on The Fate of Radionuclides in Sewage Sludge Applied to Land.'' Those findings corresponded well with results from studies addressing the fate of fallout radionuclides from the Chernobyl nuclear accident. There was an exchange of new information on a number of topics of interest to DOE waste management and environmental restoration needs.

  1. Electrical spin injection using GaCrN in a GaN based spin light emitting diode

    SciTech Connect (OSTI)

    Banerjee, D.; Ganguly, S.; Saha, D.; Adari, R.; Sankaranarayan, S.; Kumar, A.; Aldhaheri, R. W.; Hussain, M. A.; Balamesh, A. S.

    2013-12-09

    We have demonstrated electrical spin-injection from GaCrN dilute magnetic semiconductor (DMS) in a GaN-based spin light emitting diode (spin-LED). The remanent in-plane magnetization of the thin-film semiconducting ferromagnet has been used for introducing the spin polarized electrons into the non-magnetic InGaN quantum well. The output circular polarization obtained from the spin-LED closely follows the normalized in-plane magnetization curve of the DMS. A saturation circular polarization of ?2.5% is obtained at 200?K.

  2. Effects of light illumination on electron velocity of AlGaN/GaN heterostructures under high electric field

    SciTech Connect (OSTI)

    Guo, Lei; Yang, Xuelin Cheng, Jianpeng; Sang, Ling; Xu, Fujun; Tang, Ning; Feng, Zhihong; Lv, Yuanjie; Wang, Xinqiang; Shen, B.; Ge, Weikun

    2014-12-15

    We have investigated the variation of electron velocity in AlGaN/GaN heterostructures depending on illuminating light intensity and wavelength. It is shown that the electron velocity at high electric field increases under above-band light illumination. This electron velocity enhancement is found to be related to the photo-generated cold holes which interact with hot electrons and thus accelerate the energy relaxation at high electric field. The results suggest an alternative way to improve the electron energy relaxation rate and hence the electron velocity in GaN based heterostructures.

  3. Microscopic, electrical and optical studies on InGaN/GaN quantum wells based LED devices

    SciTech Connect (OSTI)

    Mutta, Geeta Rani; Venturi, Giulia; Castaldini, Antonio; Cavallini, Anna

    2014-02-21

    We report here on the micro structural, electronic and optical properties of a GaN-based InGaN/GaN MQW LED grown by the MOVPE method. The present study shows that the threading dislocations present in these LED structures are terminated as V pits at the surface and have an impact on the electrical and optical activity of these devices. It has been pointed that these dislocations were of edge, screw and mixed types. EBIC maps suggest that the electrically active defects are screw and mixed dislocations and behave as nonradiative recombinant centres.

  4. High-power InGaAs/GaAs quantum-well laser with enhanced broad spectrum of stimulated emission

    SciTech Connect (OSTI)

    Wang, Huolei; Yu, Hongyan; Zhou, Xuliang; Kan, Qiang; Yuan, Lijun; Wang, Wei; Pan, Jiaoqing; Chen, Weixi; Ding, Ying

    2014-10-06

    We report the demonstration of an InGaAs/GaAs quantum well (QW) broadband stimulated emission laser with a structure that integrated a GaAs tunnel junction with two QW active regions. The laser exhibits ultrabroad lasing spectral coverage of ?51?nm at a center wavelength of 1060?nm with a total emission power of 790 mW, corresponding to a high average spectral power density of 15.5 mW/nm, under pulsed current conditions. Compared to traditional lasers, this laser with an asymmetric separate-confinement heterostructure shows broader lasing bandwidth and higher spectral power density.

  5. Atlanta, Georgia: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    Global Energy Holdings Group formerly Xethanol Corporation Navajo Wind Energy Plum Combustion Radiance Solar Servidyne SilvaGas Corporation FERCO Enterprises Inc Solar Systems...

  6. Atlanta Community Leaders' Institute Conference | Department...

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

    economic development; housing; and health disparities and health issues, especially the combined effects of diabetes, hypertension, and obesity known as metabolic syndrome. Dr. ...

  7. Evaporation-based Ge/.sup.68 Ga Separation

    DOE Patents [OSTI]

    Mirzadeh, Saed (Albuquerque, NM); Whipple, Richard E. (Los Alamos, NM); Grant, Patrick M. (Los Alamos, NM); O'Brien, Jr., Harold A. (Los Alamos, NM)

    1981-01-01

    Micro concentrations of .sup.68 Ga in secular equilibrium with .sup.68 Ge in strong aqueous HCl solution may readily be separated in ionic form from the .sup.68 Ge for biomedical use by evaporating the solution to dryness and then leaching the .sup.68 Ga from the container walls with dilute aqueous solutions of HCl or NaCl. The chloro-germanide produced during the evaporation may be quantitatively recovered to be used again as a source of .sup.68 Ga. If the solution is distilled to remove any oxidizing agents which may be present as impurities, the separation factor may easily exceed 10.sup.5. The separation is easily completed and the .sup.68 Ga made available in ionic form in 30 minutes or less.

  8. Linear and nonlinear optical properties of GaAs/Al{sub x}Ga{sub 1?x}As/GaAs/Al{sub y}Ga{sub 1?y}As multi-shell spherical quantum dot

    SciTech Connect (OSTI)

    Emre Kavruk, Ahmet E-mail: aekavruk@gmail.com; Koc, Fatih; Sahin, Mehmet E-mail: mehsahin@gmail.com

    2013-11-14

    In this work, the optical properties of GaAs/Al{sub x}Ga{sub 1?x}As/GaAs/Al{sub y}Ga{sub 1?y}As multi-shell quantum dot heterostructure have been studied as a function of Al doping concentrations for cases with and without a hydrogenic donor atom. It has been observed that the absorption coefficient strength and/or resonant absorption wavelength can be adjusted by changing the Al content of inner-barrier and/or outer-barrier regions. Besides, it has been shown that the donor atom has an important effect on the control of the electronic and optical properties of the structure. The results have been presented as a function of the Al contents of the inner-barrier x and outer-barrier y regions and probable physical reasons have been discussed.

  9. Vehicle Technologies Office: Graduate Automotive Technology Education

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

    (GATE) | Department of Energy Education & Workforce Development » Vehicle Technologies Office: Graduate Automotive Technology Education (GATE) Vehicle Technologies Office: Graduate Automotive Technology Education (GATE) DOE established the Graduate Automotive Technology Education (GATE) Centers of Excellence to provide future generations of engineers and scientists with knowledge and skills in advanced automotive technologies. By funding curriculum development and expansion as well as

  10. 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.

  11. Quaternary AlInGaN/InGaN quantum well on vicinal c-plane substrate for high emission intensity of green wavelengths

    SciTech Connect (OSTI)

    Park, Seoung-Hwan; Pak, Y. Eugene; Park, Chang Young; Mishra, Dhaneshwar; Yoo, Seung-Hyun; Cho, Yong-Hee Shim, Mun-Bo; Kim, Sungjin

    2015-05-14

    Electronic and optical properties of non-trivial semipolar AlInGaN/InGaN quantum well (QW) structures are investigated by using the multiband effective-mass theory and non-Markovian optical model. On vicinal c-plane GaN substrate miscut by a small angle (??GaN/InGaN system is shown to have ?3 times larger spontaneous emission peak intensity than the conventional InGaN/GaN system at green wavelength. It is attributed to much larger optical matrix element of the quaternary AlInGaN/InGaN system, derived from the reduction of internal electric field induced by polarizations. This effect exceeds the performance-degrading factor of smaller quasi-Fermi-level separation for the quaternary AlInGaN/InGaN system than that for the conventional InGaN/GaN system. Results indicate that the use of quaternary III-nitride QWs on vicinal substrates may be beneficial in improving the performance of optical devices emitting green light.

  12. CX-002603: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    DeKalb County/Metro Atlanta Alternative Fuel ProjectCX(s) Applied: A1, A9Date: 12/10/2009Location(s): Atlanta, GeorgiaOffice(s): Energy Efficiency and Renewable Energy, National Energy Technology Laboratory

  13. CX-000340: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    DeKalb County/Metro Atlanta Alternative Fuel ProjectCX(s) Applied: A1, A9Date: 12/10/2009Location(s): Atlanta, GeorgiaOffice(s): Energy Efficiency and Renewable Energy, National Energy Technology Laboratory

  14. A new InGaP/GaAs tunneling heterostructure-emitter bipolar transistor (T-HEBT)

    SciTech Connect (OSTI)

    Tsai, Jung-Hui; Lee, Ching-Sung; Lour, Wen-Shiung; Ma, Yung-Chun; Ye, Sheng-Shiun

    2011-05-15

    Excellent characteristics of an InGaP/GaAs tunneling heterostructure-emitter bipolar transistor (T-HEBT) are first demonstrated. The insertion of a thin n-GaAs emitter layer between tynneling confinement and base layers effectivelty eliminates the potential spike at base-emitter junction and reduces the collector-emitter offset voltage, while the thin InGaP tunneling confinement layer is employed to reduce the transporting time across emitter region for electrons and maintain the good confinement effect for holes. Experimentally, the studied T-HEBN exhibits a maximum current gain of 285, a relatively low offset voltage of 40 mW, and a current-gain cutoff frequency of 26.4 GHz.

  15. Technology disrupted

    SciTech Connect (OSTI)

    Papatheodorou, Y.

    2007-02-15

    Three years ago, the author presented a report on power generation technologies which in summary said 'no technology available today has the potential of becoming transformational or disruptive in the next five to ten years'. In 2006 the company completed another strategic view research report covering the electric power, oil, gas and unconventional energy industries and manufacturing industry. This article summarises the strategic view findings and then revisits some of the scenarios presented in 2003. The cost per megawatt-hour of the alternatives is given for plants ordered in 2005 and then in 2025. The issue of greenhouse gas regulation is dealt with through carbon sequestration and carbon allowances or an equivalent carbon tax. Results reveal substantial variability through nuclear power, hydro, wind, geothermal and biomass remain competitive through every scenario. Greenhouse gas scenario analysis shows coal still be viable, albeit less competitive against nuclear and renewable technologies. A carbon tax or allowance at $24 per metric ton has the same effect on IGCC cost as a sequestration mandate. However, the latter would hurt gas plants much more than a tax or allowance. Sequestering CO{sub 2} from a gas plant is almost as costly per megawatt-hour as for coal. 5 refs., 5 figs., 5 tabs.

  16. Composition and Interface Analysis of InGaN/GaN Multiquantum...

    Office of Scientific and Technical Information (OSTI)

    Resource Type: Journal Article Resource Relation: Journal Name: Journal of Vacuum Science and Technology B--Microelectronics and Nanometer Structures, 32(5):Article No....

  17. CX-001791: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    Dekalb County/Metropolitan Atlanta Alternative Fuel and Advanced Technology Vehicle Project (Atlanta)CX(s) Applied: A1, A7Date: 04/21/2010Location(s): Atlanta, GeorgiaOffice(s): Energy Efficiency and Renewable Energy, National Energy Technology Laboratory

  18. The first principle study of Ni{sub 2}ScGa and Ni{sub 2}TiGa

    SciTech Connect (OSTI)

    zduran, Mustafa; Turgut, Kemal; Arikan, Nihat; ?yigr, Ahmet; Candan, Abdullah

    2014-10-06

    We computed the electronic structure, elastic moduli, vibrational properties, and Ni{sub 2}TiGa and Ni{sub 2}ScGa alloys in the cubic L2{sub 1} structure. The obtained equilibrium lattice constants of these alloys are in good agreement with available data. In cubic systems, there are three independent elastic constants, namely C{sub 11}, C{sub 12} and C{sub 44}. We calculated elastic constants in L2{sub 1} structure for Ni{sub 2}TiGa and Ni{sub 2}ScGa using the energy-strain method. The electronic band structure, total and partial density of states for these alloys were investigated within density functional theory using the plane-wave pseudopotential method implemented in Quantum-Espresso program package. From band structure, total and projected density of states, we observed metallic characters of these compounds. The electronic calculation indicate that the predominant contributions of the density of states at Fermi level come from the Ni 3d states and Sc 3d states for Ni{sub 2}TiGa, Ni 3d states and Sc 3d states for Ni{sub 2}ScGa. The computed density of states at Fermi energy are 2.22 states/eV Cell for Ni{sub 2}TiGa, 0.76 states/eV Cell for Ni{sub 2}ScGa. The vibrational properties were obtained using a linear response in the framework at the density functional perturbation theory. For the alloys, the results show that the L2{sub 1} phase is unstable since the phonon calculations have imagine modes.

  19. Building Technologies Office Overview

    SciTech Connect (OSTI)

    2013-04-01

    Building Technologies Office Overview Presentation for the 2013 Building Technologies Office's Program Peer Review

  20. Effects of high-temperature AIN buffer on the microstructure of AlGaN/GaN HEMTs

    SciTech Connect (OSTI)

    Coerekci, S.; Oeztuerk, M. K.; Yu, Hongbo; Cakmak, M.; Oezcelik, S.; Oezbay, E.

    2013-06-15

    Effects on AlGaN/GaN high-electron-mobility transistor structure of a high-temperature AlN buffer on sapphire substrate have been studied by high-resolution x-ray diffraction and atomic force microscopy techniques. The buffer improves the microstructural quality of GaN epilayer and reduces approximately one order of magnitude the edge-type threading dislocation density. As expected, the buffer also leads an atomically flat surface with a low root-mean-square of 0.25 nm and a step termination density in the range of 10{sup 8} cm{sup -2}. Due to the high-temperature buffer layer, no change on the strain character of the GaN and AlGaN epitaxial layers has been observed. Both epilayers exhibit compressive strain in parallel to the growth direction and tensile strain in perpendicular to the growth direction. However, an high-temperature AlN buffer layer on sapphire substrate in the HEMT structure reduces the tensile stress in the AlGaN layer.

  1. p-doping-free InGaN/GaN light-emitting diode driven by three-dimensional hole gas

    SciTech Connect (OSTI)

    Zhang, Zi-Hui; Tiam Tan, Swee; Kyaw, Zabu; Liu, Wei; Ji, Yun; Ju, Zhengang; Zhang, Xueliang [LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore) [LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore); LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Physical and Mathematical Sciences, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore); Wei Sun, Xiao, E-mail: EXWSUN@ntu.edu.sg [LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore); LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Physical and Mathematical Sciences, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore); Department of Electronics and Electrical Engineering, South University of Science and Technology of China, Shenzhen, Guangdong 518055 (China); Volkan Demir, Hilmi, E-mail: VOLKAN@stanfordalumni.org [LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore); LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Physical and Mathematical Sciences, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore); Department of Electrical and Electronics, UNAM-Institute of Material Science and Nanotechnology, Bilkent University, Ankara TR-06800 (Turkey); Department of Physics, UNAM-Institute of Material Science and Nanotechnology, Bilkent University, Ankara TR-06800 (Turkey)

    2013-12-23

    Here, GaN/Al{sub x}Ga{sub 1-x}N heterostructures with a graded AlN composition, completely lacking external p-doping, are designed and grown using metal-organic-chemical-vapour deposition (MOCVD) system to realize three-dimensional hole gas (3DHG). The existence of the 3DHG is confirmed by capacitance-voltage measurements. Based on this design, a p-doping-free InGaN/GaN light-emitting diode (LED) driven by the 3DHG is proposed and grown using MOCVD. The electroluminescence, which is attributed to the radiative recombination of injected electrons and holes in InGaN/GaN quantum wells, is observed from the fabricated p-doping-free devices. These results suggest that the 3DHG can be an alternative hole source for InGaN/GaN LEDs besides common Mg dopants.

  2. Intermixing of InGaAs/GaAs Quantum Well Using Multiple Cycles Annealing Cu-doped SiO2

    SciTech Connect (OSTI)

    Hongpinyo, V; Ding, Y H; Dimas, C E; Wang, Y; Ooi, B S; Qiu, W; Goddard, L L; Behymer, E M; Cole, G D; Bond, T C

    2008-06-11

    The authors investigate the effect of intermixing in InGaAs/GaAs quantum well structure using Cu-doped SiO{sub 2}. The incorporation of Cu into the silica film yields larger bandgap shift than typical impurity-free vacancy diffusion (IFVD) method at a lower activation temperature. We also observe enhancement of the photoluminescence (PL) signal from the intermixed InGaAs/GaAs quantum well structure after being cycle-annealed at 850 C.

  3. Radiation damage of GaAs thin-film solar cells on Si substrates

    SciTech Connect (OSTI)

    Itoh, Y.; Yamaguchi, M.; Nishioka, T.; Yamamoto, A.

    1987-01-15

    1-MeV electron irradiation damages in GaAs thin-film solar cells on Si substrates are examined for the first time. Damage constant for minority-carrier diffusion length in GaAs heteroepitaxial films on Si substrates is found to be the same as that in GaAs homoepitaxial films on GaAs substrates. This agreement suggests that GaAs/Si has the same defect introduction rate with radiation as GaAs/GaAs. The degradation of GaAs solar cells on Si with electron irradiation is less than that of GaAs solar cells on GaAs, because in the present, GaAs films on Si substrates have lower minority-carrier diffusion length compared to GaAs films on GaAs and these films are insensitive to radiation. The p/sup +/-p/sup +/-n AlGaAs-GaAs heteroface solar cell with junction depth of about 0.3 ..mu..m is concluded to be useful for a high-efficiency and radiation-resistant solar cell fabricated on a Si substrate.

  4. 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

  5. Theory of the electronic structure of dilute bismide and bismide-nitride alloys of GaAs: Tight-binding and k.p models

    SciTech Connect (OSTI)

    Usman, Muhammad; Broderick, Christopher A.; O'Reilly, Eoin P.

    2013-12-04

    The addition of dilute concentrations of bismuth (Bi) into GaAs to form GaBi{sub x}As{sub 1?x} alloys results in a large reduction of the band gap energy (E{sub g}) accompanied by a significant increase of the spin-orbit-splitting energy (?{sub SO}), leading to an E{sub g} < ?{sub SO} regime for x ? 10% which is technologically relevant for the design of highly efficient photonic devices. The quaternary alloy GaBi{sub x}N{sub y}As{sub 1?x?y} offers further flexibility for band gap tuning, because both nitrogen and bismuth can independently induce band gap reduction. This work reports sp{sup 3}s* tight binding and 14-band k?p models for the study of the electronic structure of GaBi{sub x}As{sub 1?x} and GaBi{sub x}N{sub y}As{sub 1?x?y} alloys. Our results are in good agreement with the available experimental data.

  6. Technology Name

    Energy Savers [EERE]

    Tech Fact Sheet Site Project & Identifier Tech Stage: Development DE-EM0000598 D&D KM-IT For the deployment of Information Technology for D&D knowledge management Page 1 of 2 Florida International University Florida D&D Knowledge Management Information Tool Challenge Deactivation and decommissioning (D&D) work is a high priority across the DOE Complex. The D&D community associated with the various DOE sites has gained extensive knowledge and experience over the years. To

  7. Technology Name

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

    Tech Fact Sheet Site Project & Identifier Tech Stage: Development DE-EM0000598 D&D KM-IT For the deployment of Information Technology for D&D knowledge management Page 1 of 2 Florida International University Florida D&D Knowledge Management Information Tool Challenge Deactivation and decommissioning (D&D) work is a high priority across the DOE Complex. The D&D community associated with the various DOE sites has gained extensive knowledge and experience over the years. To

  8. TECHNOLOGY TRANSFER

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

    404-NOV. 1, 2000 TECHNOLOGY TRANSFER COMMERCIALIZATION ACT OF 2000 VerDate 11-MAY-2000 04:52 Nov 16, 2000 Jkt 089139 PO 00000 Frm 00001 Fmt 6579 Sfmt 6579 E:\PUBLAW\PUBL404.106 APPS27 PsN: PUBL404 114 STAT. 1742 PUBLIC LAW 106-404-NOV. 1, 2000 Public Law 106-404 106th Congress An Act To improve the ability of Federal agencies to license federally owned inventions. Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled, SECTION 1. SHORT

  9. Laser Gain and Threshold Properties in Compressive-Strained and Lattice-Matched GaInNAs/GaAs Quantum Wells

    SciTech Connect (OSTI)

    Chow, W.W.; Jones, E.D.; Modine, N.A.; Allerman, A.A.; Kurtz, S.R.

    1999-08-04

    The optical gain spectra for compressive-strained and lattice-matched GaInNAs/GaAs quantum wells are computed using a microscopic laser theory. From these spectra, the peak gain and carrier radiative decay rate as functions of carrier density are determined. These dependences allow the study of lasing threshold current density for different GAInNAs/GaAs laser structures.

  10. Radiation resistance of GaAs-GaAlAs vertical cavity surface emitting lasers

    SciTech Connect (OSTI)

    Jabbour, J.; Zazoui, M.; Sun, G.C.; Bourgoin, J.C.; Gilard, O.

    2005-02-15

    The variations of the optical and electrical characteristics of a vertical cavity surface emitting laser based on GaAs quantum wells have been monitored versus irradiation with 1 MeV electrons. The results are understood by the introduction of nonradiative recombination centers in the wells whose characteristics, capture cross section for minority carriers times their introduction rate, can be determined. A similar study performed for proton irradiation shows that the results can be explained in the same way when the introduction rate of the defects is replaced by the proton energy loss into atomic collisions. These results allow us to deduce the equivalence between electron and proton irradiations: A flux of 1 proton cm{sup -2} which loses an energy E{sub nl} (eV) into atomic collisions is equivalent to a fluence of about 9x10{sup -2} E{sub nl} cm{sup -2}, 1 MeV electrons.

  11. Ultraviolet GaN photodetectors on Si via oxide buffer heterostructures with integrated short period oxide-based distributed Bragg reflectors and leakage suppressing metal-oxide-semiconductor contacts

    SciTech Connect (OSTI)

    Szyszka, A. E-mail: adam.szyszka@pwr.wroc.pl; Haeberlen, M.; Storck, P.; Thapa, S. B.; Schroeder, T.

    2014-08-28

    Based on a novel double step oxide buffer heterostructure approach for GaN integration on Si, we present an optimized Metal-Semiconductor-Metal (MSM)-based Ultraviolet (UV) GaN photodetector system with integrated short-period (oxide/Si) Distributed Bragg Reflector (DBR) and leakage suppressing Metal-Oxide-Semiconductor (MOS) electrode contacts. In terms of structural properties, it is demonstrated by in-situ reflection high energy electron diffraction and transmission electron microscopy-energy dispersive x-ray studies that the DBR heterostructure layers grow with high thickness homogeneity and sharp interface structures sufficient for UV applications; only minor Si diffusion into the Y{sub 2}O{sub 3} films is detected under the applied thermal growth budget. As revealed by comparative high resolution x-ray diffraction studies on GaN/oxide buffer/Si systems with and without DBR systems, the final GaN layer structure quality is not significantly influenced by the growth of the integrated DBR heterostructure. In terms of optoelectronic properties, it is demonstrated thatwith respect to the basic GaN/oxide/Si system without DBRthe insertion of (a) the DBR heterostructures and (b) dark current suppressing MOS contacts enhances the photoresponsivity below the GaN band-gap related UV cut-off energy by almost up to two orders of magnitude. Given the in-situ oxide passivation capability of grown GaN surfaces and the one order of magnitude lower number of superlattice layers in case of higher refractive index contrast (oxide/Si) systems with respect to classical III-N DBR superlattices, virtual GaN substrates on Si via functional oxide buffer systems are thus a promising robust approach for future GaN-based UV detector technologies.

  12. NATIONAL ENERGY TECHNOLOGY LABORATORY Technology Transfer

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

    NETL Issues Licenses for its Arc Position Sensing Technology Success Story The U.S. Department of Energy's National Energy Technology Laboratory (NETL) has issued two licenses involving its Arc Position Sensing (APS) technology to KW Associates LLC , an Oregon-based company founded by the technology's inventors. APS technology is a patented, award- winning measurement technology developed for the specialty metals industry to identify arc distribution conditions during arc melting. The unique

  13. NREL: Technology Transfer - Technologies Available for Licensing

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

    Technologies Available for Licensing Photo of NREL scientist in the NREL Hydrogen Lab. NREL's scientists and engineers develop award-winning technologies available for licensing. NREL scientists and engineers produce breakthrough and award-winning renewable energy and energy efficiency technologies that are available for licensing. We have many licensing opportunities for NREL-developed technologies, including our featured LED technologies. To see all our technologies available for licensing,

  14. Distributed Energy Technology Characterization (Desiccant Technologies),

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

    January 2004 | Department of Energy Characterization (Desiccant Technologies), January 2004 Distributed Energy Technology Characterization (Desiccant Technologies), January 2004 The purpose of this report is to characterize desiccant technology and applications, and to show how these technologies can be designed to utilize the available thermal energy from a combined heat and power (CHP) system. This technology characterization is intended to provide decision-makers and system developers

  15. High Impact Technology Catalyst: Technology Deployment Strategies |

    Energy Savers [EERE]

    Department of Energy Catalyst: Technology Deployment Strategies High Impact Technology Catalyst: Technology Deployment Strategies The Energy Department released the High Impact Technology Catalyst: Technology Deployment Strategies to serve as an overview of the HIT Catalyst program activities, including a summary of the selection process undertaken to identify, evaluate and prioritize the current HITs, descriptions of the technologies and markets for each HIT, and plans for deployment. PDF

  16. NETL Technologies Recognized for Technology Development, Transfer |

    Office of Environmental Management (EM)

    Department of Energy Recognized for Technology Development, Transfer NETL Technologies Recognized for Technology Development, Transfer October 25, 2013 - 1:31pm Addthis Did you know? The Federal Laboratory Consortium for Technology Transfer is the nationwide network of federal laboratories that provides the forum to develop strategies and opportunities for linking laboratory mission technologies and expertise with the marketplace. In consonance with the Federal Technology Transfer Act of

  17. Nano-scale luminescence characterization of individual InGaN/GaN quantum wells stacked in a microcavity using scanning transmission electron microscope cathodoluminescence

    SciTech Connect (OSTI)

    Schmidt, Gordon Mller, Marcus; Veit, Peter; Bertram, Frank; Christen, Jrgen; Glauser, Marlene; Carlin, Jean-Franois; Cosendey, Gatien; Butt, Raphal; Grandjean, Nicolas

    2014-07-21

    Using cathodoluminescence spectroscopy directly performed in a scanning transmission electron microscope at liquid helium temperatures, the optical and structural properties of a 62 InGaN/GaN multiple quantum well embedded in an AlInN/GaN based microcavity are investigated at the nanometer scale. We are able to spatially resolve a spectral redshift between the individual quantum wells towards the surface. Cathodoluminescence spectral linescans allow directly visualizing the critical layer thickness in the quantum well stack resulting in the onset of plastic relaxation of the strained InGaN/GaN system.

  18. Antaki, G.A. 22 NUCLEAR REACTOR TECHNOLOGY; 99 MATHEMATICS, COMPUTERS...

    Office of Scientific and Technical Information (OSTI)

    PIPES; DYNAMIC LOADS; ANALYTIC FUNCTIONS; ANALYTICAL SOLUTION; STRESSES; REGULATIONS; SEISMIC EFFECTS; STRESS ANALYSIS; EPRI; STANDARDS The paper addresses several analytical...

  19. Vehicle Technologies Office: 2009 Advanced Vehicle Technology...

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

    Vehicle Technology Analysis and Evaluation Activities and Heavy Vehicle Systems Optimization Program Annual Progress Report Vehicle Technologies Office: 2009 Advanced Vehicle ...

  20. Vehicle Technologies Office: 2008 Advanced Vehicle Technology...

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

    Vehicle Technology Analysis and Evaluation Activities and Heavy Vehicle Systems Optimization Program Annual Progress Report Vehicle Technologies Office: 2008 Advanced Vehicle ...

  1. Distributed Energy Technology Characterization (Desiccant Technologies...

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

    applications, and to show how these technologies can be designed to utilize the available thermal energy from a combined heat and power (CHP) system. This technology...

  2. Nuclear Science & Technology

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

    Nuclear Science & Technology Nuclear Science & Technology1354608000000Nuclear Science & TechnologySome of these resources are LANL-only and will require Remote Access. No...

  3. Alloy inhomogeneity and carrier localization in AlGaN sections and AlGaN/AlN nanodisks in nanowires with 240350?nm emission

    SciTech Connect (OSTI)

    Himwas, C.; Hertog, M. den; Dang, Le Si; Songmuang, R.; Monroy, E.

    2014-12-15

    We present structural and optical studies of AlGaN sections and AlGaN/AlN nanodisks (NDs) in nanowires grown by plasma-assisted molecular beam epitaxy. The Al-Ga intermixing at Al(Ga)N/GaN interfaces and the chemical inhomogeneity in AlGaN NDs evidenced by scanning transmission electron microscopy are attributed to the strain relaxation process. This interpretation is supported by the three-dimensional strain distribution calculated by minimizing the elastic energy in the structure. The alloy inhomogeneity increases with the Al content, leading to enhanced carrier localization signatures in the luminescence characteristics, i.e., red shift of the emission, s-shaped temperature dependence, and linewidth broadening. Despite these effects, the emission energy of AlGaN/AlN NDs can be tuned in the 240350?nm range with internal quantum efficiencies around 30%.

  4. Polycrystalline MBE-grown GaAs for solar cells

    SciTech Connect (OSTI)

    Friedman, D.J.; Kurtz, S.R.; Kibbler, A.E.; Al-Jassim, M.; Jones, K.; Keyes, B.; Matson, R.

    1997-02-01

    This paper will discuss initial studies of thin-film GaAs grown by molecular-beam epitaxy for use in developing a thin-film GaAs solar cell. Photocurrent and photoluminescence intensity are related to the material morphology as a function of growth conditions. Growth temperature and V/III ratio have a dramatic effect on the photocurrent. However, it seems likely that even after optimizing such growth parameters, it will be necessary to provide substrates that can provide templates to enhance grain size from the start of thin-film growth. {copyright} {ital 1997 American Institute of Physics.}

  5. Polycrystalline MBE-grown GaAs for solar cells

    SciTech Connect (OSTI)

    Friedman, D. J.; Kurtz, Sarah R.; Kibbler, A. E.; Al-Jassim, M.; Jones, K.; Keyes, B.; Matson, R.

    1997-02-15

    This paper will discuss initial studies of thin-film GaAs grown by molecular-beam epitaxy for use in developing a thin-film GaAs solar cell. Photocurrent and photoluminescence intensity are related to the material morphology as a function of growth conditions. Growth temperature and V/III ratio have a dramatic effect on the photocurrent. However, it seems likely that even after optimizing such growth parameters, it will be necessary to provide substrates that can provide templates to enhance grain size from the start of thin-film growth.

  6. Graphene/GaN diodes for ultraviolet and visible photodetectors

    SciTech Connect (OSTI)

    Lin, Fang; Chen, Shao-Wen; Meng, Jie; Tse, Geoffrey; Fu, Xue-Wen; Xu, Fu-Jun [State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing 100871 (China); Shen, Bo; Liao, Zhi-Min, E-mail: liaozm@pku.edu.cn, E-mail: yudp@pku.edu.cn; Yu, Da-Peng, E-mail: liaozm@pku.edu.cn, E-mail: yudp@pku.edu.cn [State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing 100871 (China); Collaborative Innovation Center of Quantum Matter, Beijing (China)

    2014-08-18

    The Schottky diodes based on graphene/GaN interface are fabricated and demonstrated for the dual-wavelength photodetection of ultraviolet (UV) and green lights. The physical mechanisms of the photoelectric response of the diodes with different light wavelengths are different. For UV illumination, the photo-generated carriers lower the Schottky barrier and increase the photocurrent. For green light illumination, as the photon energy is smaller than the bandgap of GaN, the hot electrons excited in graphene via internal photoemission are responsible for the photoelectric response. Using graphene as a transparent electrode, the diodes show a ?mS photoresponse, providing an alternative route toward multi-wavelength photodetectors.

  7. 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.

  8. Electronic contribution to friction on GaAs

    SciTech Connect (OSTI)

    Applied Science and Technology Graduate Group, UC Berkeley; Dept. of Materials Sciences and Engineering, UC Berkeley; Salmeron, Miquel; Qi, Yabing; Park, J.Y.; Hendriksen, B.L.M.; Ogletree, D.F.; Salmeron, Miquel

    2008-04-15

    The electronic contribution to friction at semiconductor surfaces was investigated by using a Pt-coated tip with 50nm radius in an atomic force microscope sliding against an n-type GaAs(100) substrate. The GaAs surface was covered by an approximately 1 nm thick oxide layer. Charge accumulation or depletion was induced by the application of forward or reverse bias voltages. We observed a substantial increase in friction force in accumulation (forward bias) with respect to depletion (reverse bias). We propose a model based on the force exerted by the trapped charges that quantitatively explains the experimental observations of excess friction.

  9. GA Hot Cell D&D Closeout Report

    Office of Legacy Management (LM)

    GENERAL ATOMICS HOT CELL FACILITY DECONTAMINATION & DECOMMISSIONING PROJECT FINAL PROJECT CLOSEOUT REPORT prepared for GA HOT CELL D&D PROJECT CONTRACT NUMBERS DE-AC03-84SF11962 and DE-AC03-95SF20798 PBS VL-GA-0012 Approvals Prepared by: James Davis, III Date Project Manager, Oakland Environmental Programs Office Reviewed by: John Lee Date Deputy, Oakland Environmental Programs Office Approved by: Laurence McEwen Date Acting Director, Oakland Environmental Programs Office General Atomics

  10. 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.

  11. Strong enhancement of terahertz emission from GaAs in InAs/GaAs quantum dot structures

    SciTech Connect (OSTI)

    Estacio, Elmer; Pham, Minh Hong; Takatori, Satoru; Cadatal-Raduban, Marilou; Nakazato, Tomoharu; Shimizu, Toshihiko; Sarukura, Nobuhiko; Somintac, Armando; Defensor, Michael; Awitan, Fritz Christian B.; Jaculbia, Rafael B.; Salvador, Arnel; Garcia, Alipio

    2009-06-08

    We report on the intense terahertz emission from InAs/GaAs quantum dot (QD) structures grown by molecular beam epitaxy. Results reveal that the QD sample emission was as high as 70% of that of a p-type InAs wafer, the most intense semiconductor emitter to date. Excitation wavelength studies showed that the emission was due to absorption in strained undoped GaAs, and corresponds to a two order-of-magnitude enhancement. Moreover, it was found that multilayer QDs emit more strongly compared with a single layer QD sample. At present, we ascribe the intense radiation to huge strain fields at the InAs/GaAs interface.

  12. Fabrication and Characterization of a Single Hole Transistor in p-type GaAs/AlGaAs Heterostructures

    SciTech Connect (OSTI)

    Tracy, Lisa A; Reno, John L.; Hargett, Terry W.

    2015-09-01

    Most spin qubit research to date has focused on manipulating single electron spins in quantum dots. However, hole spins are predicted to have some advantages over electron spins, such as reduced coupling to host semiconductor nuclear spins and the ability to control hole spins electrically using the large spin-orbit interaction. Building on recent advances in fabricating high-mobility 2D hole systems in GaAs/AlGaAs heterostructures at Sandia, we fabricate and characterize single hole transistors in GaAs. We demonstrate p-type double quantum dot devices with few-hole occupation, which could be used to study the physics of individual hole spins and control over coupling between hole spins, looking towards eventual applications in quantum computing. Intentionally left blank

  13. Characteristics of InGaP/InGaAs pseudomorphic high electron mobility transistors with triple delta-doped sheets

    SciTech Connect (OSTI)

    Chu, Kuei-Yi; Chiang, Meng-Hsueh Cheng, Shiou-Ying; Liu, Wen-Chau

    2012-02-15

    Fundamental and insightful characteristics of InGaP/InGaAs double channel pseudomorphic high electron mobility transistors (DCPHEMTs) with graded and uniform triple {delta}-doped sheets are coomprehensively studied and demonstrated. To gain physical insight, band diagrams, carrier densities, and direct current characteristics of devices are compared and investigated based on the 2D semiconductor simulator, Atlas. Due to uniform carrier distribution and high electron density in the double InGaAs channel, the DCPHEMT with graded triple {delta}-doped sheets exhibits better transport properties, higher and linear transconductance, and better drain current capability as compared with the uniformly triple {delta}-doped counterpart. The DCPHEMT with graded triple {delta}-doped structure is fabricated and tested, and the experimental data are found to be in good agreement with simulated results.

  14. Terahertz intersubband absorption in non-polar m-plane AlGaN/GaN quantum wells

    SciTech Connect (OSTI)

    Edmunds, C.; Malis, O.; Shao, J.; Shirazi-HD, M.; Manfra, M. J.

    2014-07-14

    We demonstrate THz intersubband absorption (15.626.1?meV) in m-plane AlGaN/GaN quantum wells. We find a trend of decreasing peak energy with increasing quantum well width, in agreement with theoretical expectations. However, a blue-shift of the transition energy of up to 14?meV was observed relative to the calculated values. This blue-shift is shown to decrease with decreasing charge density and is, therefore, attributed to many-body effects. Furthermore, a??40% reduction in the linewidth (from roughly 8 to 5?meV) was obtained by reducing the total sheet density and inserting undoped AlGaN layers that separate the wavefunctions from the ionized impurities in the barriers.

  15. High-performance broadband optical coatings on InGaN/GaN solar cells for multijunction device integration

    SciTech Connect (OSTI)

    Young, N. G. Farrell, R. M.; Iza, M.; Speck, J. S.; Perl, E. E.; Keller, S.; Bowers, J. E.; Nakamura, S.; DenBaars, S. P.

    2014-04-21

    We demonstrate InGaN/GaN multiple quantum well solar cells grown by metalorganic chemical vapor deposition on a bulk (0001) substrate with high-performance broadband optical coatings to improve light absorption. A front-side anti-reflective coating and a back-side dichroic mirror were designed to minimize front surface reflections across a broad spectral range and maximize rear surface reflections only in the spectral range absorbed by the InGaN, making the cells suitable for multijunction solar cell integration. Application of optical coatings increased the peak external quantum efficiency by 56% (relative) and conversion efficiency by 37.5% (relative) under 1 sun AM0 equivalent illumination.

  16. Airports & Lodging | Savannah River Ecology Laboratory

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

    Airports and Lodging AIRPORTS Augusta, GA Augusta Regional Airport (Bush Field) - closest commercial airport; Delta and U.S. Express. Daniel Field - private planes, rentals, or chartered flights. Columbia, SC Columbia Metropolitan Airport - all major carriers; 1.5-2h drive to SREL. Atlanta, GA Hartsfield Airport - all major carriers; 2.5-3 hour drive from Atlanta, GA, to Aiken, SC. LODGING No lodging is available at SREL. However, hotels and motels are available in Aiken, SC, and Augusta, GA.

  17. Current transient spectroscopy for trapping analysis on Au-free AlGaN/GaN Schottky barrier diode

    SciTech Connect (OSTI)

    Hu, J. Groeseneken, G.; Stoffels, S.; Lenci, S.; Venegas, R.; Decoutere, S.; Bakeroot, B.

    2015-02-23

    This paper presents a combined technique of high voltage off-state stress and current transient measurements to investigate the trapping/de-trapping characteristics of Au-free AlGaN/GaN Schottky barrier diodes. The device features a symmetric three-terminal structure with a central anode contact surrounded by two separate cathodes. Under the diode off-state stress conditions, the two separate cathodes were electrically shorted. The de-trapping dynamics was studied by monitoring the recovery of the two-dimensional electron gas (2DEG) current at different temperatures by applying 0.5?V at cathode 2 while grounding cathode 1. During the recovery, the anode contact acts as a sensor of changes in diode leakage current. This leakage variation was found to be mainly due to the barrier height variation. With this method, the energy level and capture cross section of different traps in the AlGaN/GaN Schottky barrier diode can be extracted. Furthermore, the physical location of different trapping phenomena is indicated by studying the variation of the diode leakage current during the recovery. We have identified two distinct trapping mechanisms: (i) electron trapping at the AlGaN surface in the vicinity of the Schottky contact which results in the leakage reduction (barrier height ?{sub B} increase) together with R{sub ON} degradation; (ii) the electron trapping in the GaN channel layer which partially depletes the 2DEG. The physical origin of the two different traps is discussed in the text.

  18. InGaAs/GaAsP strain balanced multi-quantum wires grown on misoriented GaAs substrates for high efficiency solar cells

    SciTech Connect (OSTI)

    Alonso-lvarez, D.; Thomas, T.; Fhrer, M.; Hylton, N. P.; Ekins-Daukes, N. J.; Lackner, D.; Philipps, S. P.; Bett, A. W.; Sodabanlu, H.; Fujii, H.; Watanabe, K.; Sugiyama, M.; Nasi, L.; Campanini, M.

    2014-08-25

    Quantum wires (QWRs) form naturally when growing strain balanced InGaAs/GaAsP multi-quantum wells (MQW) on GaAs [100] 6 misoriented substrates under the usual growth conditions. The presence of wires instead of wells could have several unexpected consequences for the performance of the MQW solar cells, both positive and negative, that need to be assessed to achieve high conversion efficiencies. In this letter, we study QWR properties from the point of view of their performance as solar cells by means of transmission electron microscopy, time resolved photoluminescence and external quantum efficiency (EQE) using polarised light. We find that these QWRs have longer lifetimes than nominally identical QWs grown on exact [100] GaAs substrates, of up to 1??s, at any level of illumination. We attribute this effect to an asymmetric carrier escape from the nanostructures leading to a strong 1D-photo-charging, keeping electrons confined along the wire and holes in the barriers. In principle, these extended lifetimes could be exploited to enhance carrier collection and reduce dark current losses. Light absorption by these QWRs is 1.6 times weaker than QWs, as revealed by EQE measurements, which emphasises the need for more layers of nanostructures or the use light trapping techniques. Contrary to what we expected, QWR show very low absorption anisotropy, only 3.5%, which was the main drawback a priori of this nanostructure. We attribute this to a reduced lateral confinement inside the wires. These results encourage further study and optimization of QWRs for high efficiency solar cells.

  19. Defect-Reduction Mechanism for Improving Radiative Efficiency in InGaN/GaN Light-Emitting Diodes using InGaN Underlayers

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

    Armstrong, Andrew M.; Bryant, Benjamin N.; Crawford, Mary H.; Koleske, Daniel D.; Lee, Stephen R.; Wierer, Jr., Jonathan J.

    2015-04-01

    The influence of a dilute InxGa1-xN (x~0.03) underlayer (UL) grown below a single In0.16Ga0.84N quantum well (SQW), within a light-emitting diode(LED), on the radiative efficiency and deep level defect properties was studied using differential carrier lifetime (DCL) measurements and deep level optical spectroscopy (DLOS). DCL measurements found that inclusion of the UL significantly improved LED radiative efficiency. At low current densities, the non-radiative recombination rate of the LED with an UL was found to be 3.9 times lower than theLED without an UL, while the radiative recombination rates were nearly identical. This, then, suggests that the improved radiative efficiency resultedmore » from reduced non-radiative defect concentration within the SQW. DLOS measurement found the same type of defects in the InGaN SQWs with and without ULs. However, lighted capacitance-voltage measurements of the LEDs revealed a 3.4 times reduction in a SQW-related near-mid-gap defect state for the LED with an UL. Furthermore, quantitative agreement in the reduction of both the non-radiative recombination rate (3.9×) and deep level density (3.4×) upon insertion of an UL corroborates deep level defect reduction as the mechanism for improved LED efficiency.« less

  20. Reduced Cu(InGa)Se2 Thickness in Solar Cells Using a Superstrate Configuration

    SciTech Connect (OSTI)

    Shafarman, William N.

    2015-03-30

    This project by the Institute of Energy Conversion (IEC) and the Department of Electrical and Computer Engineering at the University of Delaware sought to develop the technology and underlying science to enable reduced cost of Cu(InGa)Se2 manufacturing by reducing the thickness of the Cu(InGa)Se2 absorber layer by half compared to typical production. The approach to achieve this was to use the superstrate cell configuration in which light is incident on the cell through the glass. This structure facilitates optical enhancement approaches needed to achieve high efficiency with Cu(InGa)Se2 thicknesses less than 1 m. The primary objective was to demonstrate a Cu(InGa)Se2 cell with absorber thickness 0.5 - 0.7 m and 17% efficiency, along with a quantitative loss analysis to define a pathway to 20% efficiency. Additional objectives were the development of stable TCO and buffer layers or contact layers to withstand the Cu(InGa)Se2 deposition temperature and of advanced optical enhancement methods. The underlying fundamental science needed to effectively transition these outcomes to large scale was addressed by extensive materials and device characterization and by development of comprehensive optical models. Two different superstrate configurations have been investigated. A frontwall cell is illuminated through the glass to the primary front junction of the device. This configuration has been used for previous efforts on superstrate Cu(InGa)Se2 but performance has been limited by interdiffusion or reaction with CdS or other buffer layers. In this project, several approaches to overcome these limitations were explored using CdS, ZnO and ZnSe buffer layers. In each case, mechanisms that limit device performance were identified using detailed characterization of the materials and junctions. Due to the junction formation difficulties, efforts were concentrated on a new backwall configuration in which light is incident through the substrate into the back of the absorber layer. The primary junction is then formed after Cu(InGa)Se2 deposition. This allows the potential benefits of superstrate cells for optical enhancement while maintaining processing advantages of the substrate configuration and avoiding the harmful effects of high temperature deposition on p-n junction formation. Backwall devices have outperformed substrate cells at absorber thicknesses of 0.1-0.5 m through enhanced JSC due to easy incorporation of a Ag reflector and, with light incident on the absorber, the elimination of parasitic absorption in the CdS buffer. An efficiency of 9.7% has been achieved for a backwall Cu(InGa)Se2 device with absorber thickness ~0.4 ?m. A critical achievement that enabled implementation of the backwall cell was the development of a transparent back contact using MoO3 or WO3. Processes for controlled deposition of each material by reactive rf sputtering from metal targets were developed. These contacts have wide bandgaps making them well-suited for application as contacts for backwall devices as well as potential use in bifacial cells and as the top cell of tandem CuInSe2-based devices. Optical enhancement will be critical for further improvements. Wet chemical texturing of ZnO films has been developed for a simple, low cost light-trapping scheme for backwall superstrate devices to enhance long wavelength quantum efficiency. An aqueous oxalic acid etch was developed and found to strongly texture sputtered ZnO with high haze ? 0.9 observed across the whole spectrum. And finally, advanced optical models have been developed to assist the characterization and optimization of Cu(InGa)Se2 cells with thin absorbers

  1. Vehicle Technologies Office Propulsion Materials Technologies

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

    Vehicle Technologies Office Propulsion Materials Technologies Jerry Gibbs eere.energy.gov 2 | Vehicle Technologies Program Materials Technologies Materials Technologies $35.6 M Lightweight Materials $28.5 M Values are FY15 enacted Propulsion Materials $7.1 M Properties and Manufacturing Multi-Material Enabling Modeling & Computational Mat. Sci. Engine Materials, Cast Al & Fe High Temp Alloys Exhaust Sys. Materials, Low T Catalysts Lightweight Propulsion FY13 Enacted $27.5 M $11.9 M FY14

  2. Properties of H, O and C in GaN

    SciTech Connect (OSTI)

    Pearton, S.J.; Abernathy, C.R.; Lee, J.W.

    1996-04-01

    The electrical properties of the light ion impurities H, O and C in GaN have been examined in both as-grown and implanted material. H is found to efficiently passivate acceptors such as Mg, Ca and C. Reactivation occurs at {ge} 450 C and is enhanced by minority carrier injection. The hydrogen does not leave the GaN crystal until > 800 C, and its diffusivity is relatively high ({approximately} 10{sup {minus}11} cm{sup 2}/s) even at low temperatures (< 200 C) during injection by wet etching, boiling in water or plasma exposure. Oxygen shows a low donor activation efficiency when implanted into GaN, with an ionization level of 30--40 meV. It is essentially immobile up to 1,100 C. Carbon can produce low p-type levels (3 {times} 10{sup 17} cm{sup {minus}3}) in GaN during MOMBE, although there is some evidence it may also create n-type conduction in other nitrides.

  3. Multiscale twin hierarchy in NiMnGa shape memory alloys with...

    Office of Scientific and Technical Information (OSTI)

    Multiscale twin hierarchy in NiMnGa shape memory alloys with Fe and Cu Citation Details In-Document Search Title: Multiscale twin hierarchy in NiMnGa shape memory alloys with Fe ...

  4. Surface Chemistry of GaP(001) and InP(001) in Contact with Water...

    Office of Scientific and Technical Information (OSTI)

    Surface Chemistry of GaP(001) and InP(001) in Contact with Water Citation Details In-Document Search Title: Surface Chemistry of GaP(001) and InP(001) in Contact with Water You...

  5. ScGaN alloy growth by molecular beam epitaxy: Evidence for a...

    Office of Scientific and Technical Information (OSTI)

    ScGaN alloy growth by molecular beam epitaxy: Evidence for a metastable layered hexagonal phase Citation Details In-Document Search Title: ScGaN alloy growth by molecular beam...

  6. Improved InGaN LED System Efficacy and Cost via Droop Reduction...

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

    Improved InGaN LED System Efficacy and Cost via Droop Reduction Improved InGaN LED System Efficacy and Cost via Droop Reduction Lead Performer: Lumileds, LLC - San Jose, CA DOE ...

  7. Ge doped GaN with controllable high carrier concentration for...

    Office of Scientific and Technical Information (OSTI)

    Ge doped GaN with controllable high carrier concentration for plasmonic applications Citation Details In-Document Search Title: Ge doped GaN with controllable high carrier...

  8. Bismuth-induced phase control of GaAs nanowires grown by molecular...

    Office of Scientific and Technical Information (OSTI)

    Bismuth-induced phase control of GaAs nanowires grown by molecular beam epitaxy Citation Details In-Document Search Title: Bismuth-induced phase control of GaAs nanowires grown by ...

  9. Testing a GaAs cathode in SRF gun

    SciTech Connect (OSTI)

    Wang, E.; Kewisch, J.; Ben-Zvi, I.; Burrill, A.; Rao, T.; Wu, Q.; Holmes, D.

    2011-03-28

    RF electron guns with a strained superlattice GaAs cathode are expected to generate polarized electron beams of higher brightness and lower emittance than do DC guns, due to their higher field gradient at the cathode's surface and lower cathode temperature. We plan to install a bulk GaAs:Cs in a SRF gun to evaluate the performance of both the gun and the cathode in this environment. The status of this project is: In our 1.3 GHz 1/2 cell SRF gun, the vacuum can be maintained at nearly 10{sup -12} Torr because of cryo-pumping at 2K. With conventional activation of bulk GaAs, we obtained a QE of 10% at 532 nm, with lifetime of more than 3 days in the preparation chamber and have shown that it can survive in transport from the preparation chamber to the gun. The beam line has been assembled and we are exploring the best conditions for baking the cathode under vacuum. We report here the progress of our test of the GaAs cathode in the SRF gun. Future particle accelerators, such as eRHIC and the ILC require high-brightness, high-current polarized electrons. Strained superlattice GaAs:Cs has been shown to be an efficient cathode for producing polarized electrons. Activation of GaAs with Cs,O(F) lowers the electron affinity and makes it energetically possible for all the electrons, excited into the conduction band that drift or diffuse to the emission surface, to escape into the vacuum. Presently, all operating polarized electron sources, such as the CEBAF, are DC guns. In these devices, the excellent ultra-high vacuum extends the lifetime of the cathode. However, the low field gradient on the photocathode's emission surface of the DC guns limits the beam quality. The higher accelerating gradients, possible in the RF guns, generate a far better beam. Until recently, most RF guns operated at room temperature, limiting the vacuum to {approx}10{sup -9} Torr. This destroys the GaAs's NEA surface. The SRF guns combine the excellent vacuum conditions of DC guns and the high accelerating gradient of the RF guns, potentially offering a long lived cathode with very low emittance. Testing this concept requires preparation of the cathode, transportation to the SRF gun and evaluation of the performance of the cathode and the gun at cryogenic temperatures. In our work at BNL, we successfully activated the bulk GaAs in the preparation chamber. The highest quantum efficient was 10% at 532 nm that fell to 0.5% after 100 hours. We explored three different ways to activate the GaAs. We verified that the GaAs photocathode remains stable for 30 hours in a 10{sup -11} Torr vacuum. Passing the photocathode through the low 10{sup -9} Torr transfer section in several seconds caused the QE to drop to 0.8%. The photocathode with 0.8% QE can be tested for the SRF gun. The gun and beam pipe were prepared and assembled. After baking at 200 C baking, the vacuum of the gun and beam pipe can sustain a low 10{sup -11} Torr at room temperature. The final test to extract electrons from the gun is ongoing. In this paper, we discuss our progress with this SRF gun and the results of the photocathode in preparation chamber and in magnet transfer line.

  10. EIS-0476: Vogtle Electric Generating Plant in Burke County, GA | Department

    Office of Environmental Management (EM)

    of Energy 6: Vogtle Electric Generating Plant in Burke County, GA EIS-0476: Vogtle Electric Generating Plant in Burke County, GA February 8, 2012 EIS-0476: Final Environmental Impact Statement Department of Energy Loan Guarantees for Proposed Units 3 and 4 at the Vogtle Electric Generating Plant, Burke County, GA February 25, 2014 EIS-0476: Record of Decision Department of Energy Loan Guarantees for Proposed Units 3 and 4 at the Vogtle Electric Generating Plant, Burke County, GA

  11. Quaternary InGaAsSb Thermophotovoltaic Diodes

    SciTech Connect (OSTI)

    MW Dashiell; JF Beausang; H Ehsani; GJ Nichols; DM Depoy; LR Danielson; P Talamo; KD Rahner; EJ Brown; SR Burger; PM Foruspring; WF Topper; PF Baldasaro; CA Wang; R Huang; M Connors; G Turner; Z Shellenbarger; G Taylor; J Li; R Martinelli; D Donetski; S Anikeev; G Belenky; S Luryi

    2006-03-09

    In{sub x}Ga{sub 1-x}As{sub y}Sb{sub 1-y} thermophotovoltaic (TPV) diodes were grown lattice-matched to GaSb substrates by Metal Organic Vapor Phase Epitaxy (MOVPE) in the bandgap range of E{sub G} = 0.5 to 0.6eV. InGaAsSb TPV diodes, utilizing front-surface spectral control filters, are measured with thermal-to-electric conversion efficiency and power density of {eta}{sub TPV} = 19.7% and PD =0.58 W/cm{sup 2} respectively for a radiator temperature of T{sub radiator} = 950 C, diode temperature of T{sub diode} = 27 C, and diode bandgap of E{sub G} = 0.53eV. Practical limits to TPV energy conversion efficiency are established using measured recombination coefficients and optical properties of front surface spectral control filters, which for 0.53eV InGaAsSb TPV energy conversion is {eta}{sub TPV} = 28% and PD = 0.85W/cm{sup 2} at the above operating temperatures. The most severe performance limits are imposed by (1) diode open-circuit voltage (VOC) limits due to intrinsic Auger recombination and (2) parasitic photon absorption in the inactive regions of the module. Experimentally, the diode V{sub OC} is 15% below the practical limit imposed by intrinsic Auger recombination processes. Analysis of InGaAsSb diode electrical performance vs. diode architecture indicate that the V{sub OC} and thus efficiency is limited by extrinsic recombination processes such as through bulk defects.

  12. On the redox origin of surface trapping in AlGaN/GaN high electron mobility transistors

    SciTech Connect (OSTI)

    Gao, Feng; Chen, Di; Tuller, Harry L.; Thompson, Carl V.; Palacios, Toms

    2014-03-28

    Water-related redox couples in ambient air are identified as an important source of the surface trapping states, dynamic on-resistance, and drain current collapse in AlGaN/GaN high electron mobility transistors (HEMTs). Through in-situ X-ray photoelectron spectroscopy (XPS), direct signature of the water-related specieshydroxyl groups (OH) was found at the AlGaN surface at room temperature. It was also found that these species, as well as the current collapse, can be thermally removed above 200?C in vacuum conditions. An electron trapping mechanism based on the H{sub 2}O/H{sub 2} and H{sub 2}O/O{sub 2} redox couples is proposed to explain the 0.5?eV energy level commonly attributed to the surface trapping states. Finally, the role of silicon nitride passivation in successfully removing current collapse in these devices is explained by blocking the water molecules away from the AlGaN surface.

  13. Plasmonic terahertz detectors based on a high-electron mobility GaAs/AlGaAs heterostructure

    SciTech Connect (OSTI)

    Bia?ek, M. Witowski, A. M.; Grynberg, M.; ?usakowski, J.; Orlita, M.; Potemski, M.; Czapkiewicz, M.; Umansky, V.

    2014-06-07

    In order to characterize magnetic field (B) tunable THz plasmonic detectors, spectroscopy experiments were carried out at liquid helium temperatures and high magnetic fields on devices fabricated on a high electron mobility GaAs/AlGaAs heterostructure. The samples were either gated (the gate of a meander shape) or ungated. Spectra of a photovoltage generated by THz radiation were obtained as a function of B at a fixed THz excitation from a THz laser or as a function of THz photon frequency at a fixed B with a Fourier spectrometer. In the first type of measurements, the wave vector of magnetoplasmons excited was defined by geometrical features of samples. It was also found that the magnetoplasmon spectrum depended on the gate geometry which gives an additional parameter to control plasma excitations in THz detectors. Fourier spectra showed a strong dependence of the magnetoplasmon resonance amplitude on the conduction-band electron filling factor which was explained within a model of the electron gas heating with THz radiation. The study allows to define both the advantages and limitations of plasmonic devices based on high-mobility GaAs/AlGaAs heterostructures for THz detection at low temperatures and high magnetic fields.

  14. High 400?C operation temperature blue spectrum concentration solar junction in GaInN/GaN

    SciTech Connect (OSTI)

    Zhao, Liang; Detchprohm, Theeradetch; Wetzel, Christian

    2014-12-15

    Transparent wide gap junctions suitable as high temperature, high flux topping cells have been achieved in GaInN/GaN by metal-organic vapor phase epitaxy. In structures of 25 quantum wells (QWs) under AM1.5G illumination, an open circuit voltage of 2.1?V is achieved. Of the photons absorbed in the limited spectral range of <450?nm, 64.2% are converted to electrons collected at the contacts under zero bias. At a fill factor of 45%, they account for a power conversion efficiency of38.6%. Under concentration, the maximum output power density per sun increases from 0.49?mW/cm{sup 2} to 0.51?mW/cm{sup 2} at 40?suns and then falls 0.42?mW/cm{sup 2} at 150?suns. Under external heating, a maximum of 0.59?mW/cm{sup 2} is reached at 250?C. Even at 400?C, the device is fully operational and exceeds room temperature performance. A defect analysis suggests that significantly higher fill factors and extension into longer wavelength ranges are possible with further development. The results prove GaInN/GaN QW solar junctions a viable and rugged topping cell for concentrator photovoltaics with minimal cooling requirements. By capturing the short range spectrum, they reduce the thermal load to any conventional cells stacked behind.

  15. Ultrasensitive detection of Hg{sup 2+} using oligonucleotide-functionalized AlGaN/GaN high electron mobility transistor

    SciTech Connect (OSTI)

    Cheng, Junjie; Li, Jiadong; Miao, Bin; Wu, Dongmin; Wang, Jine; Pei, Renjun; Wu, Zhengyan

    2014-08-25

    An oligonucleotide-functionalized ion sensitive AlGaN/GaN high electron mobility transistor (HEMT) was fabricated to detect trace amounts of Hg{sup 2+}. The advantages of ion sensitive AlGaN/GaN HEMT and highly specific binding interaction between Hg{sup 2+} and thymines were combined. The current response of this Hg{sup 2+} ultrasensitive transistor was characterized. The current increased due to the accumulation of Hg{sup 2+} ions on the surface by the highly specific thymine-Hg{sup 2+}-thymine recognition. The dynamic linear range for Hg{sup 2+} detection has been determined in the concentrations from 10{sup ?14} to 10{sup ?8} M and a detection limit below 10{sup ?14} M level was estimated, which is the best result of AlGaN/GaN HEMT biosensors for Hg{sup 2+} detection till now.

  16. An inverted AlGaAs/GaAs patterned-Ge tunnel junction cascade concentrator solar cell. Final subcontract report, 1 January 1991--31 August 1992

    SciTech Connect (OSTI)

    Venkatasubramanian, R.

    1993-01-01

    This report describes work to develop inverted-grown Al{sub 0.34}Ga{sub 0.66}As/GaAs cascades. Several significant developments are reported on as follows: (1) The AM1.5 1-sun total-area efficiency of the top Al{sub 0.34}Ga{sub 0.66}As cell for the cascade was improved from 11.3% to 13.2% (NREL measurement [total-area]). (2) The ``cycled`` organometallic vapor phase epitaxy growth (OMVPE) was studied in detail utilizing a combination of characterization techniques including Hall-data, photoluminescence, and secondary ion mass spectroscopy. (3) A technique called eutectic-metal-bonding (EMB) was developed by strain-free mounting of thin GaAs-AlGaAs films (based on lattice-matched growth on Ge substrates and selective plasma etching of Ge substrates) onto Si carrier substrates. Minority-carrier lifetime in an EMB GaAs double-heterostructure was measured as high as 103 nsec, the highest lifetime report for a freestanding GaAs thin film. (4) A thin-film, inverted-grown GaAs cell with a 1-sun AM1.5 active-area efficiency of 20.3% was obtained. This cell was eutectic-metal-bonded onto Si. (5) A thin-film inverted-grown, Al{sub 0.34}Ga{sub 0.66}As/GaAs cascade with AM1.5 efficiency of 19.9% and 21% at 1-sun and 7-suns, respectively, was obtained. This represents an important milestone in the development of an AlGaAs/GaAs cascade by OMVPE utilizing a tunnel interconnect and demonstrates a proof-of-concept for the inverted-growth approach.

  17. Innovative Technologies for Bioenergy Technologies Incubator...

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

    00PM EDT Online The Innovative Technologies for Bioenergy Technologies Incubator 2 FOA Informational Webinar will be held Wednesday, September 2, 1:00 p.m.-2:00 p.m. ET. Standard...

  18. Geothermal Technologies Office - Webmaster | Department of Energy

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

    Technologies Office - Webmaster Geothermal Technologies Office - Webmaster

  19. Absorption enhancement through Fabry-Prot resonant modes in a 430?nm thick InGaAs/GaAsP multiple quantum wells solar cell

    SciTech Connect (OSTI)

    Behaghel, B.; Tamaki, R.; Watanabe, K.; Sodabanlu, H.; Vandamme, N.; Dupuis, C.; Bardou, N.; Cattoni, A.; Okada, Y.; Sugiyama, M.; Collin, S.; Guillemoles, J.-F.

    2015-02-23

    We study light management in a 430?nm-thick GaAs p-i-n single junction solar cell with 10 pairs of InGaAs/GaAsP multiple quantum wells (MQWs). The epitaxial layer transfer on a gold mirror improves light absorption and increases the external quantum efficiency below GaAs bandgap by a factor of four through the excitation of Fabry-Perot resonances. We show a good agreement with optical simulation and achieve around 10% conversion efficiency. We demonstrate numerically that this promising result can be further improved by anti-reflection layers. This study paves the way to very thin MQWs solar cells.

  20. Plasma technology directory

    SciTech Connect (OSTI)

    Ward, P.P.; Dybwad, G.L.

    1995-03-01

    The Plasma Technology Directory has two main goals: (1) promote, coordinate, and share plasma technology experience and equipment within the Department of Energy; and (2) facilitate technology transfer to the commercial sector where appropriate. Personnel are averaged first by Laboratory and next by technology area. The technology areas are accelerators, cleaning and etching deposition, diagnostics, and modeling.

  1. Nanoscale selective area growth of thick, dense, uniform, In-rich, InGaN

    Office of Scientific and Technical Information (OSTI)

    nanostructure arrays on GaN/sapphire template (Journal Article) | SciTech Connect Nanoscale selective area growth of thick, dense, uniform, In-rich, InGaN nanostructure arrays on GaN/sapphire template Citation Details In-Document Search Title: Nanoscale selective area growth of thick, dense, uniform, In-rich, InGaN nanostructure arrays on GaN/sapphire template Authors: Sundaram, S. [1] ; Puybaret, R. [2] ; El Gmili, Y. [1] ; Li, X. [2] ; Bonanno, P. L. [1] ; Pantzas, K. [3] Search SciTech

  2. ESR Detection of optical dynamic nuclear polarization in GaAs/Al{sub

    Office of Scientific and Technical Information (OSTI)

    x}Ga{sub 1-x}As quantum wells at unity filling factor in the quantum Hall effect (Journal Article) | SciTech Connect ESR Detection of optical dynamic nuclear polarization in GaAs/Al{sub x}Ga{sub 1-x}As quantum wells at unity filling factor in the quantum Hall effect Citation Details In-Document Search Title: ESR Detection of optical dynamic nuclear polarization in GaAs/Al{sub x}Ga{sub 1-x}As quantum wells at unity filling factor in the quantum Hall effect This paper presents a study of the

  3. 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.

  4. 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.

  5. Characterization and device performance of (AgCu)(InGa)Se2 absorber layers

    SciTech Connect (OSTI)

    Hanket, Gregory; Boyle, Jonathan H.; Shafarman, William N.

    2009-06-08

    The study of (AgCu)(InGa)Se2 absorber layers is of interest in that Ag-chalcopyrites exhibit both wider bandgaps and lower melting points than their Cu counterparts. (AgCu)(InGa)Se2 absorber layers were deposited over the composition range 0 < Ag/(Ag+Cu) < 1 and 0.3 < Ga/(In+Ga) < 1.0 using a variety of elemental co-evaporation processes. Films were found to be singlephase over the entire composition range, in contrast to prior studies. Devices with Ga content 0.3 < Ga/(In+Ga) <0.5 tolerated Ag incorporation up to Ag/(Ag+Cu) = 0.5 without appreciable performance loss. Ag-containing films with Ga/(In+Ga) = 0.8 showed improved device characteristics over Cu-only control samples, in particular a 30-40% increase in short-circuit current. An absorber layer with composition Ag/(Ag+Cu) = 0.75 and Ga/(In+Ga) = 0.8 yielded a device with VOC = 890 mV, JSC = 20.5mA/cm2, fill factor = 71.3%, and ? = 13.0%.

  6. Efficiency calculations of thin-film GaAs solar cells on Si substrates

    SciTech Connect (OSTI)

    Yamaguchi, M.; Amano, C.

    1985-11-01

    Dislocation effect upon the efficiency of single-crystal thin-film AlGaAs-GaAs heteroface solar cells on Si substrates is analyzed. Solar-cell properties are calculated based on a simple model; in the model, dislocations act as recombination centers to reduce the minority-carrier diffusion length in each layer and increase the space-charge layer recombination current. Numerical analysis is also carried out to optimize thin-film AlGaAs-GaAs heteroface solar-cell structures. The fabrication of thin-film AlGaAs-GaAs heteroface solar cells with a practical efficiency larger than 18% on Si substrates appears possible if the dislocation density in the thin-film GaAs layer is less than 10/sup 6/ cm/sup -2/.

  7. Optical and quantum efficiency analysis of (Ag,Cu)(In,Ga)Se2 absorber layers

    SciTech Connect (OSTI)

    Boyle, Jonathan; Hanket, Gregory; Shafarman, William

    2009-06-09

    (Ag,Cu)(In,Ga)Se2 thin films have been deposited by elemental co-evaporation over a wide range of compositions and their optical properties characterized by transmission and reflection measurements and by relative shift analysis of quantum efficiency device measurements. The optical bandgaps were determined by performing linear fits of (?h?)2 vs. h?, and the quantum efficiency bandgaps were determined by relative shift analysis of device curves with fixed Ga/(In+Ga) composition, but varying Ag/(Cu+Ag) composition. The determined experimental optical bandgap ranges of the Ga/(In+Ga) = 0.31, 0.52, and 0.82 groups, with Ag/(Cu+Ag) ranging from 0 to 1, were 1.19-1.45 eV, 1.32-1.56 eV, and 1.52-1.76 eV, respectively. The optical bowing parameter of the different Ga/(In+Ga) groups was also determined.

  8. Average Structure Evolution of ?-phase Pu-Ga Alloys

    SciTech Connect (OSTI)

    Smith, Alice Iulia; Page, Katharine L.; Gourdon, Olivier; Siewenie, Joan E.; Richmond, Scott; Saleh, Tarik A.; Ramos, Michael; Schwartz, Daniel S.

    2015-03-30

    [Full Text] Plutonium metal is a highly unusual element, exhibiting six allotropes at ambient pressure, from room temperature to its melting point. Many phases of plutonium metal are unstable with temperature, pressure, chemical additions, and time. This strongly affects structure and properties, and becomes of high importance, particularly when considering effects on structural integrity over long time periods. The fcc ?-phase deserves additional attention, not only in the context of understanding the electronic structure of Pu, but also as one of the few high-symmetry actinide phases that can be stabilized down to ambient pressure and room temperature by alloying it with trivalent elements. We will present results on recent work on aging of Pu-2at.%Ga and Pu-7at.%Ga alloys

  9. Method of plasma etching Ga-based compound semiconductors

    DOE Patents [OSTI]

    Qiu, Weibin; Goddard, Lynford L.

    2012-12-25

    A method of plasma etching Ga-based compound semiconductors includes providing a process chamber and a source electrode adjacent to the process chamber. The process chamber contains a sample comprising a Ga-based compound semiconductor. The sample is in contact with a platen which is electrically connected to a first power supply, and the source electrode is electrically connected to a second power supply. The method includes flowing SiCl.sub.4 gas into the chamber, flowing Ar gas into the chamber, and flowing H.sub.2 gas into the chamber. RF power is supplied independently to the source electrode and the platen. A plasma is generated based on the gases in the process chamber, and regions of a surface of the sample adjacent to one or more masked portions of the surface are etched to create a substantially smooth etched surface including features having substantially vertical walls beneath the masked portions.

  10. Method of plasma etching GA-based compound semiconductors

    DOE Patents [OSTI]

    Qiu, Weibin; Goddard, Lynford L.

    2013-01-01

    A method of plasma etching Ga-based compound semiconductors includes providing a process chamber and a source electrode adjacent thereto. The chamber contains a Ga-based compound semiconductor sample in contact with a platen which is electrically connected to a first power supply, and the source electrode is electrically connected to a second power supply. SiCl.sub.4 and Ar gases are flowed into the chamber. RF power is supplied to the platen at a first power level, and RF power is supplied to the source electrode. A plasma is generated. Then, RF power is supplied to the platen at a second power level lower than the first power level and no greater than about 30 W. Regions of a surface of the sample adjacent to one or more masked portions of the surface are etched at a rate of no more than about 25 nm/min to create a substantially smooth etched surface.

  11. Formation and properties of porous GaAs

    SciTech Connect (OSTI)

    Schmuki, P.; Lockwood, D.J.; Fraser, J.W.; Graham, M.J.; Isaacs, H.S.

    1996-06-01

    Porous structures on n-type GaAs (100) can be grown electrochemically in chloride-containing solutions. Crystallographic etching of the sample is a precursor stage of the attack. Polarization curves reveal the existanece of a critical onset potential for por formation (PFP). PFP is strongly dependent on the doping level of the sample and presence of surface defects. Good agreement between PFP and breakdown voltage of the space charge layer is found. Surface analysis by EDX, AES, and XPS show that the porous structure consists mainly of GaAs and that anion uptake in the structure can only observed after attackhas been initiated. Photoluminescence measurements reveal (under certain conditions) visible light emission from the porous structure.

  12. Forest products technologies

    SciTech Connect (OSTI)

    None, None

    2006-07-18

    Report highlights DOE Industrial Technology Program co-funded R&D resulting in commercial energy-efficient technologies and emerging technologies helping the forest products industry save energy.

  13. The transputer based GA. SP data acquisition system

    SciTech Connect (OSTI)

    Colombo, D.; Avano, B.; DePoli, M.; Maron, G. ); Negro, A.; Parlati, G. )

    1992-04-01

    In this paper, the new data acquisition for the GA.SP detector is presented. It is a distributed system based on a network of 40 T800 and T222 transputers linked to a VME system used for histogram storage. A 100 MBit/s FDDI ring connects the system to UNIX workstations used for the experiment control, histogram display and second level data analysis.

  14. Building Technologies Office Overview

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

    Roland Risser Director, Building Technologies Office Building Technologies Office Energy Efficiency Starts Here. 2 Building Technologies Office Integrated Approach: Improving Building Performance Research & Development Developing High Impact Technologies Standards & Codes Locking in the Savings Market Stimulation Accelerating Tech-to- Market 3 Building Technologies Office Goal: Reduce building energy use by 50% (compared to a 2010 baseline) 4 Building Technologies Office Working to

  15. SOLAR '97 CONFERENCE: MANUSCRIPT PREPARATION INSTRUCTIONS

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

    MODELING DISTRIBUTION SYSTEM IMPACTS OF SOLAR VARIABILIY AND INTERCONNECTION LOCATION Matthew J. Reno Sandia National Laboratories Georgia Institute of Technology P.O. Box 5800 MS 1033 Albuquerque, NM 87185 e-mail: matthew.reno@gatech.edu Abraham Ellis and Jimmy Quiroz Sandia National Laboratories P.O. Box 5800 MS 1033 Albuquerque, NM 87185 email: aellis@sandia.gov; jequiro@sandia.gov Santiago Grijalva Georgia Institute of Technology 777 Atlantic Drive NW, VL E284 Atlanta, GA 30332 e-mail:

  16. Ga lithography in sputtered niobium for superconductive micro and nanowires

    SciTech Connect (OSTI)

    Henry, M. David; Wolfley, Steve; Monson, Todd; Lewis, Rupert

    2014-08-18

    This work demonstrates the use of focused ion beam (FIB) implanted Ga as a lithographic mask for plasma etching of Nb films. Using a highly collimated Ga beam of a FIB, Nb is implanted 12?nm deep with a 14?nm thick Ga layer providing etch selectivity better than 15:1 with fluorine based etch chemistry. Implanted square test patterns, both 10??m by 10??m and 100??m by 100??m, demonstrate that doses above than 7.5??10{sup 15?}cm{sup ?2} at 30?kV provide adequate mask protection for a 205?nm thick, sputtered Nb film. The resolution of this dry lithographic technique is demonstrated by fabrication of nanowires 75?nm wide by 10??m long connected to 50??m wide contact pads. The residual resistance ratio of patterned Nb films was 3. The superconducting transition temperature (T{sub c})?=?7.7?K was measured using a magnetic properties measurement system. This nanoscale, dry lithographic technique was extended to sputtered TiN and Ta here and could be used on other fluorine etched superconductors such as NbN, NbSi, and NbTi.

  17. TECHNOLOGY READINESS ASSESSMENT

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

    DOENETL-20151710 U.S. Department of Energy 2014 TECHNOLOGY READINESS ASSESSMENT-CLEAN COAL RESEARCH PROGRAM 2 2014 TECHNOLOGY READINESS ASSESSMENT-CLEAN COAL RESEARCH PROGRAM ...

  18. Geothermal Technologies Office: Publications

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

    Geothermal Technologies Office Details Bookmark & Share View Related Welcome to the Energy Department's Geothermal Technologies Office Publication and Product Library. Here...

  19. Technology Selection Process

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

    technologies, including Technical Advisory Groups and the Energy Efficiency Technology Roadmap. Technical Advisory Groups E3T engages stakeholders of electric power industries in...

  20. Hydropower Program Technology Overview

    SciTech Connect (OSTI)

    Not Available

    2001-10-01

    New fact sheets for the DOE Office of Power Technologies (OPT) that provide technology overviews, description of DOE programs, and market potential for each OPT program area.

  1. Green Purchasing & Green Technology

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

    Purchasing & Technology Goals 6 & 7: Green Purchasing & Green Technology Our goal is to purchase and use environmentally sustainable products whenever possible and to implement...

  2. Promising Technologies List

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

    about promising new and underutilized energy-saving technologies available for Federal and commercial building sector deployment. To identify promising technologies,...

  3. NREL: Technology Transfer - Contacts

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

    you may have about NREL's technology transfer opportunities. Partnering with NREL Anne Miller, 303-384-7353 Licensing NREL Technologies Eric Payne, 303-275-3166 Printable Version...

  4. Science and Technology Day

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

    Science and Technology Day Science and Technology Day February 24, 2015 Tuesday, Feb. 24 Berkeley Lab Building 50 Auditorium Attendance is open to anyone. Remote streaming is...

  5. Science & Technology - 2015

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

    technology Science & Technology - 2015 October HAPLS Completes Phase 1 Energy-Ramping Campaign Shaping NIF's Beams for Direct-Drive Experiments September A Pioneering Betatron...

  6. Vehicle Technologies Office: News

    Broader source: Energy.gov [DOE]

    EERE intends to issue, on behalf of its Fuel Cell Technologies Office, a Funding Opportunity Announcement (FOA) entitled "Fuel Cell Technologies Incubator: Innovations in Fuel Cell and Hydrogen...

  7. TECHNOLOGY READINESS ASSESSMENT

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

    Pathway for readying the next generation of affordable clean energy technology -Carbon ... developed to be applicable to nuclear-fuel- waste technology, provides a ...

  8. Compositionally graded relaxed AlGaN buffers on semipolar GaN for mid-ultraviolet emission

    SciTech Connect (OSTI)

    Young, Erin C.; Wu Feng; Haeger, Daniel A.; Nakamura, Shuji; Denbaars, Steven P.; Cohen, Daniel A.; Speck, James S.; Romanov, Alexey E.

    2012-10-01

    In this Letter, we report on the growth and properties of relaxed, compositionally graded Al{sub x}Ga{sub 1-x}N buffer layers on freestanding semipolar (2021) GaN substrates. Continuous and step compositional grades with Al concentrations up to x = 0.61 have been achieved, with emission wavelengths in the mid-ultraviolet region as low as 265 nm. Coherency stresses were relaxed progressively throughout the grades by misfit dislocation generation via primary (basal) slip and secondary (non-basal) slip systems. Threading dislocation densities in the final layers of the grades were less than 10{sup 6}/cm{sup 2} as confirmed by plan-view transmission electron microscopy and cathodoluminescence studies.

  9. Study of the one dimensional electron gas arrays confined by steps in vicinal GaN/AlGaN heterointerfaces

    SciTech Connect (OSTI)

    Li, Huijie E-mail: sh-yyang@semi.ac.cn; Zhao, Guijuan; Liu, Guipeng; Wei, Hongyuan; Jiao, Chunmei; Yang, Shaoyan E-mail: sh-yyang@semi.ac.cn; Wang, Lianshan; Zhu, Qinsheng

    2014-05-21

    One dimensional electron gas (1DEG) arrays in vicinal GaN/AlGaN heterostructures have been studied. The steps at the interface would lead to the lateral barriers and limit the electron movement perpendicular to such steps. Through a self-consistent Schrdinger-Poisson approach, the electron energy levels and wave functions were calculated. It was found that when the total electron density was increased, the lateral barriers were lowered due to the screening effects by the electrons, and the electron gas became more two-dimension like. The calculated 1DEG densities were compared to the experimental values and good agreements were found. Moreover, we found that a higher doping density is more beneficial to form 1-D like electron gas arrays.

  10. Electron heating due to microwave photoexcitation in the high mobility GaAs/AlGaAs two dimensional electron system

    SciTech Connect (OSTI)

    Ramanayaka, A. N.; Mani, R. G.; Wegscheider, W.

    2013-12-04

    We extract the electron temperature in the microwave photo-excited high mobility GaAs/AlGaAs two dimensional electron system (2DES) by studying the influence of microwave radiation on the amplitude of Shubnikov-de Haas oscillations (SdHOs) in a regime where the cyclotron frequency, ?{sub c}, and the microwave angular frequency, ?, satisfy 2? ? ?{sub c} ? 3.5? The results indicate that increasing the incident microwave power has a weak effect on the amplitude of the SdHOs and therefore the electron temperature, in comparison to the influence of modest temperature changes on the dark-specimen SdH effect. The results indicate negligible electron heating under modest microwave photo-excitation, in good agreement with theoretical predictions.

  11. Origin of radiative recombination and manifestations of localization effects in GaAs/GaNAs core/shell nanowires

    SciTech Connect (OSTI)

    Chen, S. L.; Filippov, S.; Chen, W. M.; Buyanova, I. A.; Ishikawa, Fumitaro

    2014-12-22

    Radiative carrier recombination processes in GaAs/GaNAs core/shell nanowires grown by molecular beam epitaxy on a Si substrate are systematically investigated by employing micro-photoluminescence (?-PL) and ?-PL excitation (?-PLE) measurements complemented by time-resolved PL spectroscopy. At low temperatures, alloy disorder is found to cause localization of photo-excited carriers leading to predominance of optical transitions from localized excitons (LE). Some of the local fluctuations in N composition are suggested to lead to strongly localized three-dimensional confining potential equivalent to that for quantum dots, based on the observation of sharp and discrete PL lines within the LE contour. The localization effects are found to have minor influence on PL spectra at room temperature due to thermal activation of the localized excitons to extended states. Under these conditions, photo-excited carrier lifetime is found to be governed by non-radiative recombination via surface states which is somewhat suppressed upon N incorporation.

  12. Comparative investigation of InGaP/GaAs pseudomorphic field-effect transistors with triple doped-channel profiles

    SciTech Connect (OSTI)

    Tsai, Jung-Hui; Guo, Der-Feng; Lour, Wen-Shiung

    2011-09-15

    In this article, the comparison of DC performance on InGaP/GaAs pseudomorphic field-effect transistors with tripe doped-channel profiles is demonstrated. As compared to the uniform and high-medium-low doped-channel devices, the low-medium-high doped-channel device exhibits the broadest gate voltage swing and the best device linearity because more twodimensional electron gases are formed in the heaviest doped channel to enhance the magnitude of negative threshold voltage. Experimentally, the transconductance within 50% of its maximum value for gate voltage swing is 4.62 V in the low-medium-high doped-channel device, which is greater than 3.58 (3.30) V in the uniform (high-medium-low) doped-channel device.

  13. 1.9 kV AlGaN/GaN Lateral Schottky Barrier Diodes on Silicon

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

    Zhu, Mingda; Song, Bo; Qi, Meng; Hu, Zongyang; Nomoto, Kazuki; Yan, Xiaodong; Cao, Yu; Johnson, Wayne; Kohn, Erhard; Jena, Debdeep; et al

    2015-02-16

    In this letter, we present AlGaN/GaN lateral Schottky barrier diodes on silicon with recessed anodes and dual field plates. A low specific on-resistance RON,SP (5.12 mΩ · cm2), a low turn-on voltage (<0.7 V) and a high reverse breakdown voltage BV (>1.9 kV), were simultaneously achieved in devices with a 25 μm anode/cathode separation, resulting in a power figure-of-merit (FOM) BV2/RON,SP of 727 MW·cm2. The record high breakdown voltage of 1.9 kV is attributed to the dual field plate structure.

  14. Passivation of deep level states caused by misfit dislocations in InGaAs on patterned GaAs

    SciTech Connect (OSTI)

    Matragrano, M.J.; Watson, G.P.; Ast, D.G. ); Anderson, T.J.; Pathangey, B. )

    1993-03-22

    Deep level transient spectroscopy (DLTS) and cathodoluminescence (CL) were used to study the hydrogen passivation of misfit dislocations in In[sub 0.06]Ga[sub 0.94]As/GaAs heterostructures. The CL observations indicate that hydrogen plasma exposure passivates most, but not all, of the dark line defects existing in the specimen prior to hydrogenation. The concentration of deep level defect states that cannot be passivated is below the detection limit of the DLTS instrument (approximately 4[times]10[sup 12] cm[sup [minus]3]). We find the passivation is stable after anneals at temperatures as high as 600 [degree]C, indicating that hydrogen passivation of misfit dislocations is at least as stable as that of the isolated point defect studied previously with DLTS [W. C. Dautremont-Smith, J. C. Nabity, V. Swaminathan, M. Stavola, J. Chevalier, C. W. Tu, and S. J. Pearton, Appl. Phys. Lett. [bold 49] 1098 (1986)].

  15. Terrestrial Concentrator PV Modules Based on GaInP/GaAs/Ge TJ Cells and Minilens Panels

    SciTech Connect (OSTI)

    Rumyantsev, V. D.; Sadchikov, N. A.; Chalov, A. E.; Ionova, E. A.; Friedman, D. J.; Glenn, G.

    2006-01-01

    This paper is a description of research activity in the field of cost-effective modules realizing the concept of very high solar concentration with small-aperture area Fresnel lenses and multijunction III-V cells. Structural simplicity and 'all-glass' design are the guiding principles of the corresponding development. The advanced concentrator modules are made with silicone Fresnel lens panels (from 8 up to 144 lenses, each lens is 4 times 4 cm{sup 2} in aperture area) with composite structure. GaInP/GaAs/Ge triple-junction cells with average efficiencies of 31.1 and 34.7% at 1000 suns were used for the modules. Conversion efficiency as high as 26.3% has been measured indoors in a test module using a newly developed large-area solar simulator.

  16. Technology Readiness Assessment (TRA)/Technology Maturation Plan...

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

    Technology Readiness Assessment (TRA)Technology Maturation Plan (TMP) Process Guide Technology Readiness Assessment (TRA)Technology Maturation Plan (TMP) Process Guide This...

  17. DOE Vehicle Technologies Program 2009 Merit Review Report - Technology...

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

    Technology Integration and Education DOE Vehicle Technologies Program 2009 Merit Review Report - Technology Integration and Education Merit review of DOE Vehicle Technologies...

  18. Blue Spark Technologies formerly Thin Battery Technologies Inc...

    Open Energy Info (EERE)

    Spark Technologies formerly Thin Battery Technologies Inc Jump to: navigation, search Name: Blue Spark Technologies (formerly Thin Battery Technologies Inc.) Place: Westlake, Ohio...

  19. Sun Materials Technology aka Shanyang Technology | Open Energy...

    Open Energy Info (EERE)

    Technology aka Shanyang Technology Jump to: navigation, search Name: Sun Materials Technology (aka Shanyang Technology) Place: Yilan County, Taiwan Product: A US-Taiwan JV company...

  20. GT Solar Technologies formerly GT Equipment Technologies | Open...

    Open Energy Info (EERE)

    Technologies formerly GT Equipment Technologies Jump to: navigation, search Name: GT Solar Technologies (formerly GT Equipment Technologies) Place: Merrimack, New Hampshire...

  1. Quantum Fuel Systems Technologies Worldwide Inc Quantum Technologies...

    Open Energy Info (EERE)

    Fuel Systems Technologies Worldwide Inc Quantum Technologies Jump to: navigation, search Name: Quantum Fuel Systems Technologies Worldwide Inc (Quantum Technologies) Place: Irvine,...

  2. Demonstration of isotype GaN/AlN/GaN heterobarrier diodes by NH{sub 3}-molecular beam epitaxy

    SciTech Connect (OSTI)

    Fireman, Micha N.; Browne, David A.; Mazumder, Baishakhi; Speck, James S.; Mishra, Umesh K.

    2015-05-18

    The results of vertical transport through nitride heterobarrier structures grown by ammonia molecular beam epitaxy are presented. Structures are designed with binary layers to avoid the effects of random alloy fluctuations in ternary nitride barriers. The unintentional incorporation of Ga in the AlN growth is investigated by atom probe tomography and is shown to be strongly dependent on both the NH{sub 3} flowrate and substrate temperature growth parameters. Once nominally pure AlN layer growth conditions are achieved, structures consisting of unintentionally doped (UID) GaN spacer layers adjacent to a nominally pure AlN are grown between two layers of n+ GaN, from which isotype diodes are fabricated. Varying the design parameters of AlN layer thickness, UID spacer layer thickness, and threading dislocation density show marked effects on the vertical transport characteristics of these structures. The lack of significant temperature dependence, coupled with Fowler-Nordheim and/or Milliken-Lauritsen analysis, point to a prevalently tunneling field emission mechanism through the AlN barrier. Once flatband conditions in the UID layer are achieved, electrons leave the barrier with significant energy. This transport mechanism is of great interest for applications in hot electron structures.

  3. Microstructure of V-based ohmic contacts to AlGaN/GaN heterostructures at a reduced annealing temperature

    SciTech Connect (OSTI)

    Schmid, A. Schroeter, Ch.; Otto, R.; Heitmann, J.; Schuster, M.; Klemm, V.; Rafaja, D.

    2015-02-02

    Ohmic contacts with V/Al/Ni/Au and V/Ni/Au metalization schemes were deposited on AlGaN/GaN heterostructures. The dependence of the specific contact resistance on the annealing conditions and the V:Al thickness ratio was shown. For an optimized electrode stack, a low specific contact resistance of 8.9??10{sup ?6} ? cm{sup 2} was achieved at an annealing temperature of 650?C. Compared to the conventional Ti/Al/Ni/Au contact, this is a reduction of 150?K. The microstructure and contact formation at the AlGaN/metal interface were investigated by transmission electron microscopy including high-resolution micrographs and energy dispersive X-ray analysis. It was shown that for low-resistive contacts, the resistivity of the metalization has to be taken into account. The V:Al thickness ratio has an impact on the formation of different intermetallic phases and thus is crucial for establishing ohmic contacts at reduced annealing temperatures.

  4. NREL: Technology Transfer - Commercialization Programs

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

    303-275-3051. Printable Version Technology Transfer Home About Technology Transfer Technology Partnership Agreements Licensing Agreements Nondisclosure Agreements...

  5. Selective area epitaxy of monolithic white-light InGaN/GaN quantum well microstripes with dual color emission

    SciTech Connect (OSTI)

    Li, Yuejing; Tong, Yuying; Yang, Guofeng Yao, Chujun; Sun, Rui; Cai, Lesheng; Xu, Guiting; Wang, Jin; Zhang, Qing; Ye, Xuanchao; Wu, Mengting; Wen, Zhiqin

    2015-09-15

    Monolithic color synthesis is demonstrated using InGaN/GaN multiple quantum wells (QWs) grown on GaN microstripes formed by selective area epitaxy on SiO{sub 2} mask patterns. The striped microfacet structure is composed of (0001) and (11-22) planes, attributed to favorable surface polarity and surface energy. InGaN/GaN QWs on different microfacets contain spatially inhomogeneous compositions owing to the diffusion of adatoms among the facets. This unique property allows the microfacet QWs to emit blue light from the (11-22) plane and yellow light from the top (0001) plane, the mixing of which leads to the perception of white light emission.

  6. Temporally and spatially resolved photoluminescence investigation of (112{sup }2) semi-polar InGaN/GaN multiple quantum wells grown on nanorod templates

    SciTech Connect (OSTI)

    Liu, B.; Smith, R.; Athanasiou, M.; Yu, X.; Bai, J.; Wang, T.

    2014-12-29

    By means of time-resolved photoluminescence (PL) and confocal PL measurements, temporally and spatially resolved optical properties have been investigated on a number of In{sub x}Ga{sub 1?x}N/GaN multiple-quantum-well (MQW) structures with a wide range of indium content alloys from 13% to 35% on (112{sup }2) semi-polar GaN with high crystal quality, obtained through overgrowth on nanorod templates. With increasing indium content, the radiative recombination lifetime initially increases as expected, but decreases if the indium content further increases to 35%, corresponding to emission in the green spectral region. The reduced radiative recombination lifetime leads to enhanced optical performance for the high indium content MQWs as a result of strong exciton localization, which is different from the behaviour of c-plane InGaN/GaN MQWs, where quantum confined Stark effect plays a dominating role in emission process.

  7. H irradiation effects on the GaAs-like Raman modes in GaAs{sub 1-x}N{sub x}/GaAs{sub 1-x}N{sub x}:H planar heterostructures

    SciTech Connect (OSTI)

    Giulotto, E. Geddo, M.; Patrini, M.; Guizzetti, G.; Felici, M.; Capizzi, M.; Polimeni, A.; Martelli, F.; Rubini, S.

    2014-12-28

    The GaAs-like longitudinal optical phonon frequency in two hydrogenated GaAs{sub 1-x}N{sub x}/GaAs{sub 1-x}N{sub x}:H microwire heterostructureswith similar N concentration, but different H dose and implantation conditionshas been investigated by micro-Raman mapping. In the case of GaAs{sub 0.991}N{sub 0.009} wires embedded in barriers where GaAs-like properties are recovered through H irradiation, the phonon frequency in the barriers undergoes a blue shift with respect to the wires. In GaAs{sub 0.992}N{sub 0.008} wires embedded in less hydrogenated barriers, the phonon frequency exhibits an opposite behavior (red shift). Strain, disorder, phonon localization effects induced by H-irradiation on the GaAs-like phonon frequency are discussed and related to different types of N-H complexes formed in the hydrogenated barriers. It is shown that the red (blue) character of the frequency shift is related to the dominant N-2H (N-3H) type of complexes. Moreover, for specific experimental conditions, an all-optical determination of the uniaxial strain field is obtained. This may improve the design of recently presented devices that exploit the correlation between uniaxial stress and the degree of polarization of photoluminescence.

  8. Hydrogen delivery technology roadmap

    SciTech Connect (OSTI)

    None, None

    2005-11-15

    Document describing plan for research into and development of hydrogen delivery technology for transportation applications.

  9. Crosscutting Technology Research FAQs

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

    Crosscutting Technology Research FAQs faq-header-big.jpg CROSSCUTTING - BASICS Q: What is the Crosscutting Technology Research Program? A: The Crosscutting Technology Research Program focuses on enabling technologies that foster transformational developments across multiple disciplines to support energy system platforms in power system design, construction, and operation for highly efficient operation and superior environmental performance. By bridging the gap between fundamental research and

  10. Innovative Process Technologies

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

    Innovative Process Technologies Fact Sheets Research Team Members Key Contacts Innovative Process Technologies Innovative Process Technologies is concerned with the development of innovative costeffective technologies that promote efficiency, environmental performance, availability of advanced energy systems, and the development of computational tools that shorten development timelines of advanced energy systems. NETL, working with members of the NETL-Regional University Alliance (NETL-RUA),

  11. Tracers and Exploration Technologies

    Broader source: Energy.gov [DOE]

    Below are the project presentations and respective peer review results for Tracers and Exploration Technologies.

  12. NATIONAL ENERGY TECHNOLOGY LABORATORY Technology Transfer Novel...

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

    Novel PlatinumChromium Alloy for the Manufacture of Improved Coronary Stents Success Story NETL Technology Transfer Group techtransfer@netl.doe.gov Contact Partners A coronary...

  13. Vehicle Technologies Office: 2014 Electric Drive Technologies...

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

    Past year's reports are listed on the Annual Progress Reports page. PDF icon FY14EDTAnnualReport.pdf More Documents & Publications Vehicle Technologies Office: 2013 Advanced ...

  14. NATIONAL ENERGY TECHNOLOGY LABORATORY Technology Transfer NETL...

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

    Sorbent Technologies Licensed for Use in Biomass-to- Biofuel Conversion Process with ... as part of its spinout MG Fuels' integrated biomass-to-biofuel conversion process. ...

  15. Energy Technology Division Energy Technology Division Energy...

    Office of Scientific and Technical Information (OSTI)

    constitute or imply its endorsement, recommendation, or favoring by the United States ... sensor. 4. Technology, or the basic physical phenomena that the sensor uses to do its job. ...

  16. Reliable wet-chemical cleaning of natively oxidized high-efficiency Cu(In,Ga)Se{sub 2} thin-film solar cell absorbers

    SciTech Connect (OSTI)

    Lehmann, Jascha; Lehmann, Sebastian; Lauermann, Iver; Rissom, Thorsten; Kaufmann, Christian A.; Lux-Steiner, Martha Ch.; Br, Marcus; Sadewasser, Sascha

    2014-12-21

    Currently, Cu-containing chalcopyrite-based solar cells provide the highest conversion efficiencies among all thin-film photovoltaic (PV) technologies. They have reached efficiency values above 20%, the same performance level as multi-crystalline silicon-wafer technology that dominates the commercial PV market. Chalcopyrite thin-film heterostructures consist of a layer stack with a variety of interfaces between different materials. It is the chalcopyrite/buffer region (forming the p-n junction), which is of crucial importance and therefore frequently investigated using surface and interface science tools, such as photoelectron spectroscopy and scanning probe microscopy. To ensure comparability and validity of the results, a general preparation guide for realistic surfaces of polycrystalline chalcopyrite thin films is highly desirable. We present results on wet-chemical cleaning procedures of polycrystalline Cu(In{sub 1-x}Ga{sub x})Se{sub 2} thin films with an average x?=?[Ga]/([In]?+?[Ga])?=?0.29, which were exposed to ambient conditions for different times. The hence natively oxidized sample surfaces were etched in KCN- or NH{sub 3}-based aqueous solutions. By x-ray photoelectron spectroscopy, we find that the KCN treatment results in a chemical surface structure which is apart from a slight change in surface composition identical to a pristine as-received sample surface. Additionally, we discover a different oxidation behavior of In and Ga, in agreement with thermodynamic reference data, and we find indications for the segregation and removal of copper selenide surface phases from the polycrystalline material.

  17. Materials Science and Technology

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

    MST Materials Science and Technology Providing world-leading, innovative, and agile materials science and technology solutions for national security missions. MST is metallurgy. The Materials Science and Technology Division provides scientific and technical leadership in materials science and technology for Los Alamos National Laboratory. READ MORE MST is engineered materials. The Materials Science and Technology Division provides scientific and technical leadership in materials science and

  18. Emerging Technologies Program

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

    Emerging Technologies Program Pat Phelan Program Manager patrick.phelan@ee.doe.gov (202)287-1906 April 2, 2013 Building Technologies Office Program Peer Review 2 | Building Technologies Office eere.energy.gov How ET Fits into BTO Research & Development * Develop technology roadmaps * Prioritize opportunities * Solicit and select innovative technology solutions * Collaborate with researchers * Solve technical barriers and test innovations to prove effectiveness * Measure and validate energy

  19. TECHNOLOGY TRANSFER COORDINATORS

    Broader source: Energy.gov [DOE]

    Mark Hartney, Director of the Office of Strategic Planning, SLAC, discussed technology transfer at SLAC. Bob Hwang, Director, Transportation Energy Center, Combustion Research Facility, SNL presented on technology transfer at SNL. Elsie Quaite-Randall, Chief Technology Transfer Officer, Innovation and Partnerships Office, LBNL, presented on technology transfer at LBNL. Richard A. Rankin, Director, Industrial Partnerships Office and Economic Development Office (Interim), LLNL, presented on technology transfer at LLNL.

  20. Comparison of single junction AlGaInP and GaInP solar cells grown by molecular beam epitaxy

    SciTech Connect (OSTI)

    Masuda, T; Tomasulo, S; Lang, JR; Lee, ML

    2015-03-07

    We have investigated similar to 2.0 eV (AlxGa1-x)(0.51)In0.49P and similar to 1.9 eV Ga0.51In0.49P single junction solar cells grown on both on-axis and misoriented GaAs substrates by molecular beam epitaxy (MBE). Although lattice-matched (AlxGa1-x)(0.51)In0.49P solar cells are highly attractive for space and concentrator photovoltaics, there have been few reports on the MBE growth of such cells. In this work, we demonstrate open circuit voltages (V-oc) ranging from 1.29 to 1.30 V for Ga0.51In0.49P cells, and 1.35-1.37 V for (AlxGa1-x)(0.51)In0.49P cells. Growth on misoriented substrates enabled the bandgap-voltage offset (W-oc = E-g/q - V-oc) of Ga0.51In0.49P cells to decrease from similar to 575 mV to similar to 565 mV, while that of (AlxGa1-x)(0.51)In0.49P cells remained nearly constant at 620 mV. The constant Woc as a function of substrate offcut for (AlxGa1-x)(0.51)In0.49P implies greater losses from non-radiative recombination compared with the Ga0.51In0.49P devices. In addition to larger Woc values, the (AlxGa1-x)(0.51)In0.49P cells exhibited significantly lower internal quantum efficiency (IQE) values than Ga0.51In0.49P cells due to recombination at the emitter/window layer interface. A thin emitter design is experimentally shown to be highly effective in improving IQE, particularly at short wavelengths. Our work shows that with further optimization of both cell structure and growth conditions, MBE-grown (AlxGa1-x)(0.51)In0.49P will be a promising wide-bandgap candidate material for high-efficiency, lattice-matched multi-junction solar cells. (C) 2015 AIP Publishing LLC.

  1. 2010 DOE EERE Vehicle Technologies Program Merit Review … Technology

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

    Integration | Department of Energy … Technology Integration 2010 DOE EERE Vehicle Technologies Program Merit Review … Technology Integration Technology integration merit review results PDF icon 2010_amr_08.pdf More Documents & Publications 2012 Annual Merit Review Results Report - Technology Integration 2011 Annual Merit Review Results Report - Technology Integration DOE Vehicle Technologies Program 2009 Merit Review Report - Technology Integration and Education

  2. Quantum effects in electron beam pumped GaAs

    SciTech Connect (OSTI)

    Yahia, M. E.; National Institute of Laser Enhanced Sciences , Cairo University ; Azzouz, I. M.; Moslem, W. M.

    2013-08-19

    Propagation of waves in nano-sized GaAs semiconductor induced by electron beam are investigated. A dispersion relation is derived by using quantum hydrodynamics equations including the electrons and holes quantum recoil effects, exchange-correlation potentials, and degenerate pressures. It is found that the propagating modes are instable and strongly depend on the electron beam parameters, as well as the quantum recoil effects and degenerate pressures. The instability region shrinks with the increase of the semiconductor number density. The instability arises because of the energetic electron beam produces electron-hole pairs, which do not keep in phase with the electrostatic potential arising from the pair plasma.

  3. 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.

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

    DOE Patents [OSTI]

    Dew-Hughes, David (Bellport, NY)

    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.

  5. Structure, transport and thermal properties of UCoGa

    SciTech Connect (OSTI)

    Purwanto, A.; Robinson, R.A.; Prokes, K.

    1994-04-01

    By means of neutron powder diffraction, we find that UCoGa crystallizes in the hexagonal ZrNiAl structure and orders ferromagnetically at low temperatures with magnetic moments stacked along the c axis. The magnetic-ordering temperature is reflected in anomalies in the temperature dependencies of the electrical resistivity and the specific heat at Tc = 47 K. Furthermore, the strong anisotropy in the electrical resistivity for i {parallel} c and i {perpendicular} c indicates a significant contribution of the magnetic anisotropy to the electrical resistivity.

  6. " Best Practices Scorecard (c) GA Tech Research Corp.

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

    Best Practices Scorecard (c) GA Tech Research Corp. (c) Texas Industries of the Future" "Instructions for Using the Best Practice Scorecard Calculator" "This calculator was developed for use with the Superior Energy Performance's Best Practice Scorecard, revision 9, dated December 5, 2012." "How to use this calculator:" "1. On the Summary tab, press the hide or unhide buttons to show desired detail." "2. Click on the category links in the

  7. SHARED TECHNOLOGY TRANSFER PROGRAM

    SciTech Connect (OSTI)

    GRIFFIN, JOHN M. HAUT, RICHARD C.

    2008-03-07

    The program established a collaborative process with domestic industries for the purpose of sharing Navy-developed technology. Private sector businesses were educated so as to increase their awareness of the vast amount of technologies that are available, with an initial focus on technology applications that are related to the Hydrogen, Fuel Cells and Infrastructure Technologies (Hydrogen) Program of the U.S. Department of Energy. Specifically, the project worked to increase industry awareness of the vast technology resources available to them that have been developed with taxpayer funding. NAVSEA-Carderock and the Houston Advanced Research Center teamed with Nicholls State University to catalog NAVSEA-Carderock unclassified technologies, rated the level of readiness of the technologies and established a web based catalog of the technologies. In particular, the catalog contains technology descriptions, including testing summaries and overviews of related presentations.

  8. Unoccupied electronic structure of Ni2MnGa ferromagnetic shape memory alloy

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Unoccupied electronic structure of Ni2MnGa ferromagnetic shape memory alloy Citation Details In-Document Search This content will become publicly available on August 20, 2016 Title: Unoccupied electronic structure of Ni2MnGa ferromagnetic shape memory alloy Momentum resolved inverse photoemission spectroscopy measurements show that the dispersion of the unoccupied bands of Ni2MnGa is significant in the austenite phase. Furthermore, in the martensite phase,

  9. Enhanced magnetic hysteresis in Ni-Mn-Ga single crystal and its influence

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

    on magnetic shape memory effect (Journal Article) | SciTech Connect Enhanced magnetic hysteresis in Ni-Mn-Ga single crystal and its influence on magnetic shape memory effect Citation Details In-Document Search Title: Enhanced magnetic hysteresis in Ni-Mn-Ga single crystal and its influence on magnetic shape memory effect Enhanced magnetic hysteresis due to boron doping in combination with magnetic shape memory effect in Ni-Mn-Ga single crystal results in new interesting functionality of

  10. Enhanced photocatalytic performance of Ga{sup 3+}-doped ZnO

    SciTech Connect (OSTI)

    Zhong, Jun Bo; Li, Jian Zhang; Zeng, Jun; He, Xi Yang; Hu, Wei; Shen, Yue Cheng

    2012-11-15

    Graphical abstract: In general, the strong SPS response corresponds to the high separation rate of photoinduced charge carriers on the basis of the SPS principle. The photovoltage of Ga{sup 3+}-doped ZnO is higher than that of ZnO, thus it can be confirmed that the Ga{sup 3+}-doped ZnO has a higher charge separation rate than the ZnO sample. Among these samples, 1%Ga has highest charge separation rate. Display Omitted Highlights: ? Ga{sup 3+} has been employed to dope ZnO photocatalyst. ? Ga{sup 3+} increases the BET surface area and changes the morphology of ZnO. ? The photoinduced charge separation rate has been enhanced. ? The photocatalytic activity has been greatly promoted. -- Abstract: ZnO and Ga{sup 3+}-doped ZnO with different molar ratio of Ga/Zn (1%, 2% and 3%) were prepared by a parallel flow precipitation method. The photocatalysts prepared were characterized by BET surface area, X-ray diffraction (XRD), UV/vis diffuse reflectance spectroscopy (DRS), scanning electron microscope (SEM) and surface photovoltage spectroscopy (SPS), respectively. The results show that doping Ga{sup 3+} into ZnO increases the BET surface area. The XRD spectra of the photocatalysts calcined at 573 K show only the characteristic peaks of wurtzite-type. Ga{sup 3+}-doped ZnO absorbs much more light than ZnO in the visible light region. Doping Ga{sup 3+} into ZnO greatly changes the morphology of ZnO and enhances the photoinduced charge separation rate. The photocatalytic activity of ZnO and Ga{sup 3+}-doped ZnO for decolorization of methyl orange (MO) solution was evaluated, of all the photocatalysts prepared, the Ga{sup 3+}-doped ZnO with 1% possesses the best photocatalytic activity and the possible reason was discussed.

  11. app_d

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

    26 Appendix D Document 23, Department of Health & Human Services (Kenneth W. Holt), Atlanta, GA Page 1 of 21 - New Information - Document 22, Char Roth, Ketchum, ID Page 1 of 1 D-27 DOE/EIS-0287 Idaho HLW & FD EIS Document 23, Department of Health & Human Services (Kenneth W. Holt), Atlanta, GA Page 2 of 21 Document 23, Department of Health & Human Services (Kenneth W. Holt), Atlanta, GA Page 3 of 21 - New Information - DOE/EIS-0287 D-28 Appendix D Document 23, Department of

  12. DOE Zero Energy Ready Home Case Study: Heirloom Design Build, Euclid

    Energy Savers [EERE]

    Avenue, Atlanta, GA | Department of Energy Heirloom Design Build, Euclid Avenue, Atlanta, GA DOE Zero Energy Ready Home Case Study: Heirloom Design Build, Euclid Avenue, Atlanta, GA Case study of a DOE 2015 Housing Innovation Award winning custom home in the mixed-humid climate that got a HERS 50 without PV, with 2x6 16" on center walls with R-19 ocsf; basement with R-28 ccsf, R-5 rigid foam under slab; sealed attic with R-28 ocsf under roof deck; 22.8 SEER; 12.5 HSPF heat pump. PDF

  13. Relaxation and critical strain for maximum In incorporation in AlInGaN on GaN grown by metal organic vapour phase epitaxy

    SciTech Connect (OSTI)

    Reuters, Benjamin; Finken, M.; Wille, A.; Kalisch, H.; Vescan, A.; Hollaender, B.; Heuken, M.

    2012-11-01

    Quaternary AlInGaN layers were grown on conventional GaN buffer layers on sapphire by metal organic vapour phase epitaxy at different surface temperatures and different reactor pressures with constant precursor flow conditions. A wide range in compositions within 30-62% Al, 5-29% In, and 23-53% Ga was covered, which leads to different strain states from high tensile to high compressive. From high-resolution x-ray diffraction and Rutherford backscattering spectrometry, we determined the compositions, strain states, and crystal quality of the AlInGaN layers. Atomic force microscopy measurements were performed to characterize the surface morphology. A critical strain value for maximum In incorporation near the AlInGaN/GaN interface is presented. For compressively strained layers, In incorporation is limited at the interface as residual strain cannot exceed an empirical critical value of about 1.1%. Relaxation occurs at about 15 nm thickness accompanied by strong In pulling. Tensile strained layers can be grown pseudomorphically up to 70 nm at a strain state of 0.96%. A model for relaxation in compressively strained AlInGaN with virtual discrete sub-layers, which illustrates the gradually changing lattice constant during stress reduction is presented.

  14. Electron and hole gas in modulation-doped GaAs/Al{sub 1-x}Ga{sub x}As radial heterojunctions

    SciTech Connect (OSTI)

    Bertoni, Andrea; Royo, Miquel; Mahawish, Farah; Goldoni, Guido

    2011-11-15

    We perform self-consistent Schroedinger-Poisson calculations with exchange and correlation corrections to determine the electron and hole gas in a radial heterojunction formed in a GaAs/AlGaAs core-multi-shell nanowire, which is either n- or p-doped. We show that the electron and hole gases can be tuned to different localizations and symmetries inside the core as a function of the doping density/gate potential. Contrary to planar heterojunctions, conduction electrons do not form a uniform 2D electron gas (2DEG) localized at the GaAs/AlGaAs interface, but rather show a transition between an isotropic, cylindrical distribution deep in the GaAs core (low doping) and a set of six tunnel-coupled quasi-1D channels at the edges of the interface (high doping). Holes, on the other hand, are much more localized at the GaAs/AlGaAs interface. At low doping, they present an additional localization pattern with six separated 2DEGs strips. The field generated by a back-gate may easily deform the electron or hole gas, breaking the sixfold symmetry. Single 2DEGs at one interface or multiple quasi-1D channels are shown to form as a function of voltage intensity, polarity, and carrier type.

  15. Analysis of the GaInP/GaAs/1-eV/Ge Cell and Related Structures for Terrestrial Concentrator Application: Preprint

    SciTech Connect (OSTI)

    Friedman, D. J.; Kurtz, S. R.; Geisz, J. F.

    2002-05-01

    This conference paper describes the analysis of the potential of GaInP/GaAs/1-eV/Ge four-junction solar cell to improve on the efficiency of the state-of-the-art GaInP/GaAs/Ge benchmark. We emphasize three factors: (1) The newly proposed terrestrial concentrator spectrum has a lower ratio of red to blue light than does the old AM1.5 direct standard spectrum. (2) Standard two-layer antireflection coatings do not provide near-zero reflectance over the full spectral range of interest for these devices. (3) GaInNAs junctions used to date for the 1-eV junction have quantum efficiencies less than {approx}75%. These factors all limit the device current, adversely affecting the four-junction efficiency. We discuss strategies for ameliorating this problem, including going to alternate structures such as a GaInP/GaAs/0.9-eV three-junction device.

  16. Enhanced conversion efficiency in wide-bandgap GaNP solar cells

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

    Sukrittanon, Supanee; Liu, Ren; Ro, Yun Goo; Pan, Janet L.; Jungjohann, Katherine Leigh; Tu, Charles W.; Dayeh, Shadi A.

    2015-10-12

    In this study, we demonstrate –2.05 eV dilute nitride GaNP solar cells on GaP substrates for potential use as the top junction in dual-junction integrated cells on Si. By adding a small amount of N into indirect-bandgap GaP, GaNP has several extremely important attributes: a direct-bandgap that is also tunable, and easily attained lattice-match with Si. Our best GaNP solar cell ([N] –1.8%, Eg –2.05 eV) achieves an efficiency of 7.9%, even in the absence of a window layer. This GaNP solar cell's efficiency is 3× higher than the most efficient GaP solar cell to date and higher than othermore » solar cells with similar direct bandgap (InGaP, GaAsP). Through a systematic study of the structural, electrical, and optical properties of the device, efficient broadband optical absorption and enhanced solar cell performance are demonstrated.« less

  17. Vacancy defects in as-grown and neutron irradiated GaP studied by positrons

    SciTech Connect (OSTI)

    Dlubek, G.; Bruemmer, O.; Polity, A.

    1986-08-18

    Positron lifetime and Doppler-broadening measurements have been used to study vacancy defects in n-italic-type GaP. Vacancies in the P sublattice with a concentration of some 10/sup 17/ cm/sup -3/ were observed in as-grwon GaP. The vacancies disappear during annealing at 500--800 /sup 0/C. In neutron-irradiated GaP positrons are trapped by Ga vacancies which anneal out in two stages situated at 300--550 /sup 0/C and 550--700 /sup 0/C.

  18. Structural defects in GaN revealed by Transmission Electron Microscopy

    SciTech Connect (OSTI)

    Liliental-Weber, Zuzanna

    2014-04-18

    This paper reviews the various types of structural defects observed by Transmission Electron Microscopy in GaN heteroepitaxial layers grown on foreign substrates and homoepitaxial layers grown on bulk GaN substrates. The structural perfection of these layers is compared to the platelet self-standing crystals grown by High Nitrogen Pressure Solution. Defects in undoped and Mg doped GaN are discussed. Some models explaining the formation of inversion domains in heavily Mg doped layers that are possible defects responsible for the difficulties of p-doping in GaN are also reviewed.

  19. Relaxation of compressively strained AlGaN by inclined threading

    Office of Scientific and Technical Information (OSTI)

    dislocations. (Journal Article) | SciTech Connect Journal Article: Relaxation of compressively strained AlGaN by inclined threading dislocations. Citation Details In-Document Search Title: Relaxation of compressively strained AlGaN by inclined threading dislocations. Transmission electron microscopy and x-ray diffraction were used to assess the microstructure and strain of Al{sub x}Ga{sub 1?x}N(x = 0.61-0.64) layers grown on AlN. The compressively-strained AlGaN is partially relaxed by

  20. Enhanced magnetic hysteresis in Ni-Mn-Ga single crystal and its...

    Office of Scientific and Technical Information (OSTI)

    shape memory effect Citation Details In-Document Search Title: Enhanced magnetic hysteresis in Ni-Mn-Ga single crystal and its influence on magnetic shape memory effect ...

  1. Electronic structure of Co-Ni-Ga Heusler alloys studied by resonant

    Office of Scientific and Technical Information (OSTI)

    photoemission (Journal Article) | SciTech Connect Electronic structure of Co-Ni-Ga Heusler alloys studied by resonant photoemission Citation Details In-Document Search Title: Electronic structure of Co-Ni-Ga Heusler alloys studied by resonant photoemission The electronic structures of Co{sub 2.01}Ni{sub 1.05}Ga{sub 0.94} and Co{sub 1.76}Ni{sub 1.46}Ga{sub 0.78} Heusler alloys have been investigated by resonant photoemission spectroscopy across the 3p-3d transition of Co and Ni. For the Ni

  2. Antimonide-Based Long-Wavelength Lasers on GaAs Substrates

    SciTech Connect (OSTI)

    KLEM,JOHN F.; Blum, O.

    2000-08-17

    We have investigated the use of GaAsSb in edge-emitting laser active regions, in order to obtain lasing near 1.3 {micro}m. Single quantum well GaAsSb devices display electroluminescence at wavelengths as long as 1.34 {micro}m, but substantial blueshifts occur under high injection conditions. GaAsSb single quantum well edge emitters have been obtained which lase at 1.275 {micro}m with a room-temperature threshold current density as low as 535 A/cm{sup 2}. Modification of the basic GaAsSb/GaAs structure with the addition of InGaAs layers results in a strongly type-II band alignment which can be used to further extend the emission wavelength of these devices. Using GaAsSb/InGaAs active regions, lasers emitting at 1.17 {micro}m have been obtained with room-temperature threshold current densities of 120 A/cm{sup 2}, and devices operating at 1.29 {micro}m have displayed thresholds as low as 375 A/cm{sup 2}. Characteristic temperatures for devices employing various GaAsSb-based active regions have been measured to be 60-73 K.

  3. Enhanced conversion efficiency in wide-bandgap GaNP solar cells

    SciTech Connect (OSTI)

    Sukrittanon, Supanee; Liu, Ren; Ro, Yun Goo; Pan, Janet L.; Jungjohann, Katherine Leigh; Tu, Charles W.; Dayeh, Shadi A.

    2015-10-12

    In this study, we demonstrate –2.05 eV dilute nitride GaNP solar cells on GaP substrates for potential use as the top junction in dual-junction integrated cells on Si. By adding a small amount of N into indirect-bandgap GaP, GaNP has several extremely important attributes: a direct-bandgap that is also tunable, and easily attained lattice-match with Si. Our best GaNP solar cell ([N] –1.8%, Eg –2.05 eV) achieves an efficiency of 7.9%, even in the absence of a window layer. This GaNP solar cell's efficiency is 3× higher than the most efficient GaP solar cell to date and higher than other solar cells with similar direct bandgap (InGaP, GaAsP). Through a systematic study of the structural, electrical, and optical properties of the device, efficient broadband optical absorption and enhanced solar cell performance are demonstrated.

  4. Interface Reactions and Electrical Characteristics of Au/GaSb Contacts

    SciTech Connect (OSTI)

    H. Ehsani; R.J. Gutmann; G.W. Charache

    2000-07-07

    The reaction of Au with GaSb occurs at a relatively low temperature (100 C). Upon annealing, a AuSb{sub 2} compound and several Au-Ga phases are produced. Phase transitions occur toward higher Ga concentration with increasing annealing temperatures. Furthermore, the depth of the contact also increases with increased annealing temperature. They found that the AuSb{sub 2} compound forms on the GaSb surface, with the compound crystal partially ordered with respect to the substrate. The transition of Schottky- to ohmic-contact behavior in Au/n-type GaSb occurs simultaneously with the formation of the AuGa compound at about a 250 C annealing temperature. This ohmic contact forms without the segregation of dopants at the metallic compound/GaSb interface. Therefore it is postulated that transition from Schottky- to ohmic-contact behavior is obtained through a series of tunneling transitions of electrons through defects in the depletion region in the Au/n-type GaSb contacts. Contact resistivities of 6-7 x 10{sup -6} {Omega}-cm{sup 2} were obtained with the annealing temperature between 300 and 350 C for 30 seconds. In Au/p-type GaSb contacts, the resistivity was independent of the annealing temperature. This suggested that the carrier transport in p-type contact dominated by thermionic emission.

  5. High-temperature luminescence in an n-GaSb/n-InGaAsSb/p-AlGaAsSb light-emitting heterostructure with a high potential barrier

    SciTech Connect (OSTI)

    Petukhov, A. A., E-mail: andrey-rus29@rambler.ru; Zhurtanov, B. E.; Kalinina, K. V.; Stoyanov, N. D.; Salikhov, H. M.; Mikhailova, M. P.; Yakovlev, Yu. P. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)] [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)

    2013-09-15

    The electroluminescent properties of an n-GaSb/n-InGaAsSb/p-AlGaAsSb heterostructure with a high potential barrier in the conduction band (large conduction-band offset) at the n-GaSb/n-InGaAsSb type-II heterointerface ({Delta}E{sub c} = 0.79 eV) are studied. Two bands with peaks at 0.28 and 0.64 eV at 300 K, associated with radiative recombination in n-InGaAsSb and n-GaSb, respectively, are observed in the electroluminescence (EL) spectrum. In the entire temperature range under study, T = 290-480 K, additional electron-hole pairs are formed in the n-InGaAsSb active region by impact ionization with hot electrons heated as a result of the conduction-band offset. These pairs contribute to radiative recombination, which leads to a nonlinear increase in the EL intensity and output optical power with increasing pump current. A superlinear increase in the emission power of the long-wavelength band is observed upon heating in the temperature range T = 290-345 K, and a linear increase is observed at T > 345 K. This work for the first time reports an increase in the emission power of a light-emitting diode structure with increasing temperature. It is shown that this rise is caused by a decrease in the threshold energy of the impact ionization due to narrowing of the band gap of the active region.

  6. InGaAsN Solar Cells with 1.0eV Bandgap, Lattice Matched to GaAs

    SciTech Connect (OSTI)

    Allerman, A.A.; Banas, J.J.; Gee, J.M.; Hammons, B.E.; Jones, E.D.; Kurtz, S.R.

    1998-11-24

    The design, growth by metal-organic chemical vapor deposition, and processing of an In{sub 0.07}Ga{sub 0.93}As{sub 0.98}N{sub 0.02} solar Al, with 1.0 ev bandgap, lattice matched to GaAs is described. The hole diffusion length in annealed, n-type InGaAsN is 0.6-0.8 pm, and solar cell internal quantum efficiencies > 70% arc obwined. Optical studies indicate that defects or impurities, from InGAsN doping and nitrogen incorporation, limit solar cell performance.

  7. A comparison of the structure and localized magnetism in Ce{sub 2}PdGa{sub 12} with the heavy fermion CePdGa{sub 6}

    SciTech Connect (OSTI)

    Macaluso, Robin T. [Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803 (United States); Millican, Jasmine N. [Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803 (United States); Nakatsuji, Satoru [Department of Physics, Kyoto University, Kyoto, Japan 606-8502 (Japan); Lee, Han-Oh [Department of Physics, University of California, Davis, CA 95616 (United States); Carter, B. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Moreno, Nelson O. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Fisk, Zachary [Department of Physics, University of California, Davis, CA 95616 (United States); Chan, Julia Y. [Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803 (United States)]. E-mail: jchan@lsu.edu

    2005-11-15

    Single crystals of Ce{sub 2}PdGa{sub 12} have been synthesized in Ga flux and characterized by X-ray diffraction. This compound crystallizes in the tetragonal P4/nbm space group, Z=2 with lattice parameters of a=6.1040(2)A and c=15.5490(6)A. It shows strongly anisotropic magnetism and orders antiferromagnetically at T{sub N}{approx}11K. A field-induced metamagnetic transition to the ferromagnetic state is observed below T{sub N}. Structure-property relationships with the related heavy-fermion antiferromagnet CePdGa{sub 6} are discussed.

  8. Origin of InGaN/GaN light-emitting diode efficiency improvements using tunnel-junction-cascaded active regions

    SciTech Connect (OSTI)

    Piprek, Joachim

    2014-02-03

    This Letter investigates the efficiency enhancement achieved by tunnel junction insertion into the InGaN/GaN multi-quantum well (MQW) active region of blue light emitting diodes (LEDs). The peak quantum efficiency of such LED exceeds 100%, but the maximum wall-plug efficiency (WPE) hardly changes. However, due to the increased bias, the WPE peaks at much higher input power, i.e., the WPE droop is significantly delayed, and the output power is strongly enhanced. The main physical reason for this improvement lies in the non-uniform vertical carrier distribution typically observed within InGaN MQWs.

  9. InGaP/GaAs Inverted Dual Junction Solar Cells For CPV Applications Using Metal-Backed Epitaxial Lift-Off

    SciTech Connect (OSTI)

    Bauhuis, Gerard J.; Mulder, Peter; Haverkamp, Erik J.; Schermer, John J.; Nash, Lee J.; Fulgoni, Dominic J. F.; Ballard, Ian M.; Duggan, Geoffrey

    2010-10-14

    The epitaxial lift-off (ELO) technique has been combined with inverted III-V PV cell epitaxial growth with the aim of employing thin film PV cells in HCPV systems. In a stepwise approach to the realization of an inverted triple junction on a MELO platform we have first grown a GaAs single junction PV cell to establish the basic layer release process and cell processing steps followed by the growth, fabrication and test of an inverted InGaP/GaAs dual junction structure.

  10. SSL TECHNOLOGY DEVELOPMENT WORKSHOP

    Broader source: Energy.gov [DOE]

    Rapid advances in SSL technology make it easy to forget that this technology is still at a relatively early stage of development, and much of its potential remains untapped. The 10th annual DOE SSL...

  11. Technology Readiness Assessment Guide

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    2011-09-15

    The Guide assists individuals and teams involved in conducting Technology Readiness Assessments (TRAs) and developing Technology Maturation Plans (TMPs) for the DOE capital asset projects subject to DOE O 413.3B. Supersedes DOE G 413.3-4.

  12. Technology Deployment Case Studies

    Broader source: Energy.gov [DOE]

    Find technology deployment case studies below. Click on each individual project link to see the full case study. You can also view a map of technology deployment case studies.

  13. Tag: technology transfer

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

    17all en CNS, UT chemical sensing technology wins R&D 100 Award http:www.y12.doe.govnewspress-releasescns-ut-chemical-sensing-technology-wins-rd-100-award

  14. Open Government Technology Summit

    Broader source: Energy.gov [DOE]

    On January 25, 2012, the OCIO hosted the Open Government Technology Summit in Forrestal Auditorium.  Five speakers including Deputy U.S. Chief Technology Officer Chris Vein, DOE Director of New...

  15. Thermal influence on charge carrier transport in solar cells based on GaAs PN junctions

    SciTech Connect (OSTI)

    Osses-Mrquez, Juan; Caldern-Muoz, Williams R.

    2014-10-21

    The electron and hole one-dimensional transport in a solar cell based on a Gallium Arsenide (GaAs) PN junction and its dependency with electron and lattice temperatures are studied here. Electrons and heat transport are treated on an equal footing, and a cell operating at high temperatures using concentrators is considered. The equations of a two-temperature hydrodynamic model are written in terms of asymptotic expansions for the dependent variables with the electron Reynolds number as a perturbation parameter. The dependency of the electron and hole densities through the junction with the temperature is analyzed solving the steady-state model at low Reynolds numbers. Lattice temperature distribution throughout the device is obtained considering the change of kinetic energy of electrons due to interactions with the lattice and heat absorbed from sunlight. In terms of performance, higher values of power output are obtained with low lattice temperature and hot energy carriers. This modeling contributes to improve the design of heat exchange devices and thermal management strategies in photovoltaic technologies.

  16. Fuel Cell Technologies Overview

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

    7/21/2015 eere.energy.gov Fuel Cell Technologies Overview States Energy Advisory Board (STEAB) Washington, DC Dr. Sunita Satyapal U.S. Department of Energy Fuel Cell Technologies Program Program Manager 3/14/2012 Outline * Introduction - Technology and Market Overview * DOE Program Overview - Mission & Structure - R&D Progress - Demonstration & Deployments * State Activities - Examples of potential opportunities 2 | Fuel Cell Technologies Program Source: US DOE 7/21/2015

  17. Technology Partnership Agreements | NREL

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

    Technology Partnership Agreements Looking for Funding? We do not fund any projects under a technology partnership agreement. The partner provides the necessary resources and, in most cases, covers our costs of providing technical services. NREL does provide funding opportunities through competitively placed contracts. See procurement. There are a variety of ways to partner with NREL using technology partnership agreements. See a summary of our Fiscal Year 2015 technology partnership agreements.

  18. Geothermal Energy & Drilling Technology

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

    Energy & Drilling Technology - Sandia Energy Energy Search Icon Sandia Home Locations ... Atmospheric Radiation Measurement Climate Reasearch Facility Geomechanics and Drilling ...

  19. TECHNOLOGY READINESS ASSESSMENT

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

    DECEMBER 2012 Pathway for readying the next generation of affordable clean energy technology -Carbon Capture, Utilization, and Storage (CCUS) 2012 TECHNOLOGY READINESS ASSESSMENT -OVERVIEW 2 2012 TECHNOLOGY READINESS ASSESSMENT-OVERVIEW 2012 TECHNOLOGY READINESS ASSESSMENT-OVERVIEW 3 DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any

  20. Robert Jilek: Pellion Technologies

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

    Robert Jilek: Pellion Technologies Alumni Link: Opportunities, News and Resources for Former Employees Latest Issue:September 2015 all issues All Issues » submit Robert Jilek: Pellion Technologies Senior research scientist at eastern energy storage startup September 3, 2014 Robert Jilek Robert Jilek Contact Linda Anderman Email Robert Jilek Jilek is currently with Pellion Technologies Bob Jilek is currently spending part of his time in a management role at Pellion Technologies in the Cambridge

  1. NREL: Geothermal Technologies - Capabilities

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

    ... studies, regional sedimentary basin exploration, prospect generation, reservoir ... Technologies Office in assessment and evaluation of research and development projects. ...

  2. Membrane Technology Workshop

    Broader source: Energy.gov [DOE]

    Presentation by Charles Page (Air Products & Chemicals, Inc.) for the Membrane Technology Workshop held July 24, 2012

  3. Consumer Vehicle Technology Data

    Broader source: Energy.gov [DOE]

    2013 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting

  4. Technology Integration Overview

    Broader source: Energy.gov [DOE]

    2013 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting

  5. California Institute of Technology

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

    Sunday, July 29, 2012 California Institute of Technology Hameetman Auditorium at the Cahill Center 8:30 AM - 5:00 PM Speakers include: o Harry Atwater, Director, LMI-EFRC and Resnick Institute, California Institute of Technology o Ivan Celanovic, Principal Research Scientist, Massachusetts Institute of Technology o Geoffrey Kinsey, Director, Photovoltaic Technologies, Fraunhofer Center for Sustainable Energy o Sarah Kurtz, Principal Scientist, National Renewable Energy Laboratory o Minh Le,

  6. First National Technology Center

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

    National Technology First National Technology Center Center Dennis Hughes FMA, RPA, P.E. Lead Property Manager, First National Buildings, Inc. 2 First National Technology First National Technology Center Center First National of Nebraska, Inc. - $12 Billion Assets - 5,400 employees - 6.6 million customers in 50 states - 60 banking locations Nebraska, Colorado, Kansas, South Dakota,Texas, Illinois - Largest in house merchant processor in United States Top ten VISA® and MasterCard® processor Top

  7. Fuel Cell Technologies Overview

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

    States Energy Advisory Board (STEAB) Washington, DC Dr. Sunita Satyapal U.S. Department of Energy Fuel Cell Technologies Program Program Manager 3/14/2012 2 | Fuel Cell Technologies Program Source: US DOE 3/19/2013 eere.energy.gov * Introduction - Technology and Market Overview * DOE Program Overview - Mission & Structure - R&D Progress - Demonstration & Deployments * State Activities - Examples of potential opportunities Outline 3 | Fuel Cell Technologies Program Source: US DOE

  8. Benchmarking of Competitive Technologies

    Broader source: Energy.gov [DOE]

    2012 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting

  9. Bioenergy Technologies Office

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

    2015 BETO Project Peer Review - Conversion Area Overview Bryna Guriel, Technology Manager Conversion R&D March 23 rd 2015 2 | Bioenergy Technologies Office eere.energy.gov Introduction to Conversion R&D 3 | Bioenergy Technologies Office eere.energy.gov * The strategic goal of the conversion program is to develop commercially viable technologies for converting feedstocks via biological and chemical routes energy-dense, fungible, finished liquid fuels, such as renewable gasoline, jet, and

  10. Building Technologies Office Overview

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

    Technologies Office Roland Risser Director, Building Technologies Office National Energy Consumption 40% 60% Reducing consumption or improving performance calls for cutting-edge energy-efficient solutions Aiming High for 2030 Double U.S. energy productivity Lower building energy use by 50% Annual energy use by 20 quads 1 billion metric tons CO 2 $200 billion for America's homes and buildings Delivering Energy-Efficient Solutions Co Emerging Technologies High-impact building technologies ~Five

  11. Building Technologies Office Overview

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

    Roland Risser Director, Building Technologies Office Building Technologies Office Overview Our Homes and Buildings Use 40% of Our Nation's Energy and 75% of Electricity Energy Use Electricity Use Residential Transportation 21 quads 27 quads Commercial 18 quads Industrial 31 quads U.S. Energy Bill for Buildings: $410 billion per year 2 Building Technologies Office (BTO) Ecosystem Emerging Technologies Building Codes Appliance Standards Residential Buildings Integration Commercial Buildings

  12. Carbon Fiber Technology Facility

    Broader source: Energy.gov [DOE]

    2012 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting

  13. Carbon Fiber Technology Facility

    Broader source: Energy.gov [DOE]

    2013 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting

  14. Technology Performance Exchange

    SciTech Connect (OSTI)

    2015-09-01

    To address the need for accessible, high-quality data, the Department of Energy has developed the Technology Performance Exchange (TPEx). TPEx enables technology suppliers, third-party testing laboratories, and other entities to share product performance data. These data are automatically transformed into a format that technology evaluators can easily use in their energy modeling assessments to inform procurement decisions.

  15. High Impact Technology Hub

    Broader source: Energy.gov [DOE]

    The High Impact Technology Hub is a one stop shop for information associated with technology demonstrations in occupied, operational buildings. Resources posted to Hub should accelerate the selection and evaluation of technology demonstration projects and enable transparency into DOEs market stimulation and tech to market activities.

  16. Vehicle Technologies Office

    Broader source: Energy.gov [DOE]

    The Vehicle Technologies Office is developing more energy efficient and environmentally friendly highway transportation technologies that will enable America to use less petroleum. The long-term aim is to develop "leap frog" technologies that will provide Americans with greater freedom of mobility and energy security, while lowering costs and reducing impacts on the environment.

  17. Extremely scaled high-k/In?.??Ga?.??As gate stacks with low leakage and low interface trap densities

    SciTech Connect (OSTI)

    Chobpattana, Varistha; Mikheev, Evgeny; Zhang, Jack Y.; Mates, Thomas E.; Stemmer, Susanne

    2014-09-28

    Highly scaled gate dielectric stacks with low leakage and low interface trap densities are required for complementary metal-oxide-semiconductor technology with III-V semiconductor channels. Here, we show that a novel pre-deposition technique, consisting of alternating cycles of nitrogen plasma and tetrakis(dimethylamino)titanium, allows for HfO? and ZrO? gate stacks with extremely high accumulation capacitance densities of more than 5 ?F/cm? at 1 MHz, low leakage current, low frequency dispersion, and low midgap interface trap densities (10cm?eV?range). Using x-ray photoelectron spectroscopy, we show that the interface contains TiO? and small quantities of In?O?, but no detectable Ga- or As-oxides, or As-As bonding. The results allow for insights into the microscopic mechanisms that control leakage and frequency dispersion in high-k/III-V gate stacks.

  18. NREL: Technology Transfer - Agreements for Commercializing Technology

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

    Agreements for Commercializing Technology NREL uses Agreements for Commercializing Technology (ACT) when a partner seeks highly specialized or technical services to complete a project. An ACT agreement also authorizes participating contractor-operated DOE laboratories, such as NREL, to partner with businesses using more flexible terms that are aligned with industry practice. Read more about how this partnership tool increases flexibility. The agreement type used depends on the business, and the

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

    SciTech Connect (OSTI)

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

    2011-01-11

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

  20. Explanations of the unusual photoluminescence observed in annealed InGaN/GaN multi quantum well

    SciTech Connect (OSTI)

    Biswas, Dipankar Bera, Partha Pratim Mistry, Apu

    2015-05-15

    During growth and fabrication of devices, InGaN/GaN QWs undergo several thermal cyclings which causes redistribution of the elements, particularly In in the QW structures. This causes significant changes in the optical properties of the QWs. The thermal cyclings are often accompanied by alloy clustering and phase separation. So in order to have a deep knowledge of how the nano structures behave with thermal cyclings the process is simulated through successive annealing at high temperatures which are accompanied by photoluminescence (PL) measurements to obtain the optical properties at each stage. III-V nanostructures, in most usual cases, on annealing lead to a monotonic blue shift of the PL peak energy and goes into saturation. Recently there were reports in which the PL peak initially had a red shift which was followed by an increase in energy, a blue shift i.e. the PL peak goes through an inflexion. These unusual observations have been explained in this paper through quantum mechanical models and computations, which remained unexplained.

  1. A novel theoretical model for broadband blue InGaN/GaN superluminescent light emitting diodes

    SciTech Connect (OSTI)

    Moslehi Milani, N.; Mohadesi, V.; Asgari, A.

    2015-02-07

    A broadband superluminescent light emitting diode with In{sub 0.2}Ga{sub 0.8}N/GaN multiple quantum wells (MQWs) active region is investigated. The investigation is based on a theoretical model which includes the calculation of electronic states of the structure, rate equations, and the spectral radiation power. Two rate equations corresponding to MQW active region and separate confinement heterostructures layer are solved self-consistently with no-k selection wavelength dependent gain and quasi-Fermi level functions. Our results show that the superluminescence started in a current of ?120?mA (?7.5?kA/Cm{sup 2}) at 300?K. The range of peak emission wavelengths for different currents is 423426?nm and the emission bandwidth is ?5?nm in the superluminescence regime. A maximum light output power of 7.59 mW is obtained at 600?mA and the peak modal gain as a function of current indicates logarithmic behavior. Also, the comparison of our calculated results with published experimental data is shown to be in good agreement.

  2. Sulfuric acid and hydrogen peroxide surface passivation effects on AlGaN/GaN high electron mobility transistors

    SciTech Connect (OSTI)

    Zaidi, Z. H. Lee, K. B.; Qian, H.; Jiang, S.; Houston, P. A.; Guiney, I.; Wallis, D. J.; Humphreys, C. J.

    2014-12-28

    In this work, we have compared SiN{sub x} passivation, hydrogen peroxide, and sulfuric acid treatment on AlGaN/GaN HEMTs surface after full device fabrication on Si substrate. Both the chemical treatments resulted in the suppression of device pinch-off gate leakage current below 1??A/mm, which is much lower than that for SiN{sub x} passivation. The greatest suppression over the range of devices is observed with the sulfuric acid treatment. The device on/off current ratio is improved (from 10{sup 4}10{sup 5} to 10{sup 7}) and a reduction in the device sub-threshold (S.S.) slope (from ?215 to 90?mV/decade) is achieved. The sulfuric acid is believed to work by oxidizing the surface which has a strong passivating effect on the gate leakage current. The interface trap charge density (D{sub it}) is reduced (from 4.86 to 0.90??10{sup 12?}cm{sup ?2} eV{sup ?1}), calculated from the change in the device S.S. The gate surface leakage current mechanism is explained by combined Mott hopping conduction and Poole Frenkel models for both untreated and sulfuric acid treated devices. Combining the sulfuric acid treatment underneath the gate with the SiN{sub x} passivation after full device fabrication results in the reduction of D{sub it} and improves the surface related current collapse.

  3. The use of short-period InGaN/GaN superlattices in blue-region light-emitting diodes

    SciTech Connect (OSTI)

    Sizov, V. S., E-mail: vsizov@mail.ioffe.ru; Tsatsulnikov, A. F.; Sakharov, A. V.; Lundin, W. V.; Zavarin, E. E.; Cherkashin, N. A. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); Hytch, M. J. [National Center for Scientific Research (CNRS), Center for Material Elaboration and Structural Studies (CEMES) (France); Nikolaev, A. E. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); Mintairov, A. M.; He Yan; Merz, J. L. [University of Notre Dame, EE Department (United States)

    2010-07-15

    Optical and light-emitting diode structures with an active InGaN region containing short-period InGaN/GaN superlattices are studied. It is shown that short-period superlattices are thin two-dimensional layers with a relatively low In content that contain inclusions with a high In content 1-3 nm thick. Inclusions manifest themselves from the point of view of optical properties as a nonuniform array of quantum dots involved in a residual quantum well. The use of short-period superlattices in light-emitting diode structures allows one to decrease the concentration of nonradiative centers, as well as to increase the injection of carriers in the active region due to an increase in the effective height of the AlGaN barrier, which in general leads to an increase in the quantum efficiency of light-emitting diodes.

  4. X ray photoelectron analysis of oxide-semiconductor interface after breakdown in Al{sub 2}O{sub 3}/InGaAs stacks

    SciTech Connect (OSTI)

    Shekhter, P.; Palumbo, F.; Cohen Weinfeld, K.; Eizenberg, M.

    2014-09-08

    In this work, the post-breakdown characteristics of metal gate/Al{sub 2}O{sub 3}/InGaAs structures were studied using surface analysis by x ray photoelectron spectroscopy. The results show that for dielectric breakdown under positive bias, localized filaments consisting of oxidized substrate atoms (In, Ga and As) were formed, while following breakdown under negative bias, a decrease of oxidized substrate atoms was observed. Such differences in the microstructure at the oxide-semiconductor interface after breakdown for positive and negative voltages are explained by atomic diffusion of the contact atoms into the gate dielectric in the region of the breakdown spot by the current induced electro-migration effect. These findings show a major difference between Al{sub 2}O{sub 3}/InGaAs and SiO{sub 2}/Si interfaces, opening the way to a better understanding of the breakdown characteristics of III-V complementary-metal-oxide-semiconductor technology.

  5. Atomistic modeling and HAADF investigations of misfit and threading dislocations in GaSb/GaAs hetero-structures for applications in high electron mobility transistors

    SciTech Connect (OSTI)

    Ruterana, Pierre Wang, Yi Chen, Jun Chauvat, Marie-Pierre; El Kazzi, S.; Deplanque, L.; Wallart, X.

    2014-10-06

    A detailed investigation on the misfit and threading dislocations at GaSb/GaAs interface has been carried out using molecular dynamics simulation and quantitative electron microscopy techniques. The sources and propagation of misfit dislocations have been elucidated. The nature and formation mechanisms of the misfit dislocations as well as the role of Sb on the stability of the Lomer configuration have been explained.

  6. NNMI Industry Day: Smart Manufacturing AMO Overview

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

    1 | Energy Efficiency and Renewable Energy eere.energy.gov Mark Johnson Director Advanced Manufacturing Office www.manufacturing.energy.gov NNMI Industry Day: Smart Manufacturing AMO Overview February 25, 2015 Atlanta, GA Status Quo: Products invented here, and made elsewhere 2 Significance of U.S. Manufacturing 12% of U.S. GDP, 12 million U.S. jobs, 60% of U.S. Exports U.S. Trade Balance of Advanced Technology Swung to historic deficit, lost 1/3 rd of workforce 3 Clean Energy: Nexus of

  7. Spin-Torque

    Office of Scientific and Technical Information (OSTI)

    Spin-Torque in Systems with Inhomogeneous Magnetization Grant No. DE-FG02-04ER46170 Final Technical Report for 9/1/2004 - 8/31/2009 Andrew Zangwill School of Physics, Georgia Institute of Technology, Atlanta, GA 30332-0430 (Dated: April 22, 2013) I. OVERVIEW The work performed under this grant focused on the phenomenon of spin-transfer torque. This is a quantum mechanical effect whereby the angular momentum of conduction electrons is transferred to the magnetization of ferromagnetic structures.

  8. Geoplasma LLC | Open Energy Information

    Open Energy Info (EERE)

    LLC Place: Atlanta, Georgia Zip: 30363 Product: Geoplasma is developing plasma gasification technology. Coordinates: 33.748315, -84.391109 Show Map Loading map......

  9. Energy Department Invests $600,000 in University-Industry Partnerships...

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

    funding, develop partnerships with industry, and improve manufacturing education. ... Georgia Institute of Technology (Atlanta, Georgia): Georgia Tech will support 20 student ...

  10. Plum Combustion | Open Energy Information

    Open Energy Info (EERE)

    Plum Combustion Place: Atlanta, Georgia Product: Combustion technology, which reduces NOx-emissions. Coordinates: 33.748315, -84.391109 Show Map Loading map......

  11. Downstream Savings: From Water Efficiency to Energy Savings

    Broader source: Energy.gov [DOE]

    Presenters: Sean West, United Technologies Corporation; Jean Pullen, Southface (representing the City of Atlanta); Lindsay Wilkinson, InterContinental Hotels Group

  12. Vehicle Technologies Office Merit Review 2014: Carbon Fiber Technology...

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

    Carbon Fiber Technology Facility Vehicle Technologies Office Merit Review 2014: Carbon Fiber Technology Facility Presentation given by Oak Ridge National Laboratory at 2014 DOE ...

  13. Vehicle Technologies Office: 2010 Fuel Technologies R&D Annual...

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

    Vehicle Technologies Office: 2010 Fuel Technologies R&D Annual Progress Report The Fuels Technologies subprogram supports fuels and lubricants research and development (R&D)...

  14. 2010 DOE EERE Vehicle Technologies Program Merit Review ? Technology...

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

    Integration 2011 Annual Merit Review Results Report - Technology Integration DOE Vehicle Technologies Program 2009 Merit Review Report - Technology Integration and Education...

  15. Vehicle Technologies Office Merit Review 2015: Advanced Technology...

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

    Advanced Technology Vehicle Lab Benchmarking (L1&L2) Vehicle Technologies Office Merit Review 2015: Advanced Technology Vehicle Lab Benchmarking (L1&L2) Presentation given by Argonne ...

  16. Vehicle Technologies Office Merit Review 2014: Advanced Technology...

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

    Advanced Technology Vehicle Lab Benchmarking - Level 1 Vehicle Technologies Office Merit Review 2014: Advanced Technology Vehicle Lab Benchmarking - Level 1 Presentation given by ...

  17. In-situ surface composition measurements of CuGaSe{sub 2} thin films

    SciTech Connect (OSTI)

    Fons, P.; Yamada, A.; Niki, S.; Oyanagi, H.

    1998-12-31

    Two CuGaSe{sub 2} films were grown by molecular beam epitaxy onto GaAs (001) substrates with varying Cu/Ga flux ratios under Se overpressure conditions. Growth was interrupted at predetermined times and the surface composition was measured using Auger electron spectroscopy after which growth was continued. After growth, the film composition was analyzed using voltage dependent electron microprobe spectroscopy. Film structure and morphology were also analyzed using x-ray diffraction and atomic force microscopy. The film with a Cu/Ga ratio larger than unity showed evidence of surface segregation of a second Cu-rich phase with a Cu/Se composition ratio slightly greater than unity. A second CuGaSe{sub 2} film with a Cu/Ga ratio of less than unity showed no change in surface composition with time and was also consistent with bulk composition measurements. Diffraction measurements indicated a high concentration of twins as well as the presence of domains with mixed c and a axes in the Ga-rich film. The Cu-rich films by contrast were single domain and had a narrower mosaics. High sensitivity scans along the [001] reciprocal axis did not exhibit any new peaks not attributable to either the substrate or the CuGaSe{sub 2} thin film.

  18. Development of a Low Cost Insulated Foil Substrate for Cu(InGaSe)2 Photovoltaics

    SciTech Connect (OSTI)

    ERTEN ESER

    2012-01-22

    The project validated the use of stainless steel flexible substrate coated with silicone-based resin dielectric, developed by Dow Corning Corporation, for Cu(InGa)Se2 based photovoltaics. The projects driving force was the high performance of Cu(InGa)Se2 based photovoltaics coupled with potential cost reduction that could be achieved with dielectric coated SS web substrate.

  19. Deep-level transient spectroscopy of InAs/GaAs quantum dot superlattices

    SciTech Connect (OSTI)

    Sobolev, M. M.; Nevedomskii, V. N.; Zolotareva, R. V.; Vasil'ev, A. P.; Ustinov, V. M.

    2014-02-21

    Deep level transient spectroscopy (DLTS) has been applied to study the carrier emission from states of a 10-layer system of tunnel-coupled vertically correlated quantum dots (VCQDs) in p-n InAs/GaAs heterostructures with different widths of GaAs spacers under varied reverse bias (U{sub r}) and filling voltage pulse U{sub f}.

  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. Variation of lattice constant and cluster formation in GaAsBi

    SciTech Connect (OSTI)

    Puustinen, J.; Schramm, A.; Guina, M.; Wu, M.; Luna, E.; Laukkanen, P.; Laitinen, M.; Sajavaara, T.

    2013-12-28

    We investigate the structural properties of GaAsBi layers grown by molecular beam epitaxy on GaAs at substrate temperatures between 220315 C. Irrespective of the growth temperature, the structures exhibited similar Bi compositions, and good overall crystal quality as deduced from X-Ray diffraction measurements. After thermal annealing at temperatures as low as 500 C, the GaAsBi layers grown at the lowest temperatures exhibited a significant reduction of the lattice constant. The lattice variation was significantly larger for Bi-containing samples than for Bi-free low-temperature GaAs samples grown as a reference. Rutherford backscattering spectrometry gave no evidence of Bi diffusing out of the layer during annealing. However, dark-field and Z-contrast transmission electron microscopy analyses revealed the formation of GaAsBi clusters with a Bi content higher than in the surrounding matrix, as well as the presence of metallic As clusters. The apparent reduction of the lattice constant can be explained by a two-fold process: the diffusion of the excess As incorporated within As{sub Ga} antisites to As clusters, and the reduction of the Bi content in the GaAs matrix due to diffusion of Bi to GaAsBi clusters. Diffusion of both As and Bi are believed to be assisted by the native point defects, which are present in the low-temperature as-grown material.

  2. InGaN-based thin film solar cells: Epitaxy, structural design, and photovoltaic properties

    SciTech Connect (OSTI)

    Sang, Liwen; Liao, Meiyong; Koide, Yasuo; Sumiya, Masatomo

    2015-03-14

    In{sub x}Ga{sub 1?x}N, with the tunable direct bandgaps from ultraviolet to near infrared region, offers a promising candidate for the high-efficiency next-generation thin-film photovoltaic applications. Although the adoption of thick InGaN film as the active region is desirable to obtain efficient light absorption and carrier collection compared to InGaN/GaN quantum wells structure, the understanding on the effect from structural design is still unclear due to the poor-quality InGaN films with thickness and difficulty of p-type doping. In this paper, we comprehensively investigate the effects from film epitaxy, doping, and device structural design on the performances of the InGaN-based solar cells. The high-quality InGaN thick film is obtained on AlN/sapphire template, and p-In{sub 0.08}Ga{sub 0.92}N is achieved with a high hole concentration of more than 10{sup 18?}cm{sup ?3}. The dependence of the photovoltaic performances on different structures, such as active regions and p-type regions is analyzed with respect to the carrier transport mechanism in the dark and under illumination. The strategy of improving the p-i interface by using a super-thin AlN interlayer is provided, which successfully enhances the performance of the solar cells.

  3. Effect of the band structure of InGaN/GaN quantum well on the surface plasmon enhanced light-emitting diodes

    SciTech Connect (OSTI)

    Li, Yi; Zhang, Rong E-mail: bliu@nju.edu.cn; Liu, Bin E-mail: bliu@nju.edu.cn; Xie, Zili; Zhang, Guogang; Tao, Tao; Zhuang, Zhe; Zhi, Ting; Zheng, Youdou

    2014-07-07

    The spontaneous emission (SE) of InGaN/GaN quantum well (QW) structure with silver(Ag) coated on the n-GaN layer has been investigated by using six-by-six K-P method taking into account the electron-hole band structures, the photon density of states of surface plasmon polariton (SPP), and the evanescent fields of SPP. The SE into SPP mode can be remarkably enhanced due to the increase of electron-hole pairs near the Ag by modulating the InGaN/GaN QW structure or increasing the carrier injection. However, the ratio between the total SE rates into SPP mode and free space will approach to saturation or slightly decrease for the optimized structures with various distances between Ag film and QW layer at a high injection carrier density. Furthermore, the Ga-face QW structure has a higher SE rate than the N-face QW structure due to the overlap region of electron-hole pairs nearer to the Ag film.

  4. Performance of single-junction and dual-junction InGaP/GaAs solar cells under low concentration ratios

    SciTech Connect (OSTI)

    Khan, Aurangzeb; Yamaguchi, Masafumi; Takamoto, Tatsuya

    2004-10-11

    A study of the performance of single-junction InGaP/GaAs and dual-junction InGaP/GaAs tandem cells under low concentration ratios (up to 15 suns), before and after 1 MeV electron irradiation is presented. Analysis of the tunnel junction parameters under different concentrated light illuminations reveals that the peak current (J{sub P}) and valley current (J{sub V}) densities should be greater than the short-circuit current density (J{sub sc}) for better performance. The tunnel junction behavior against light intensity improved after irradiation. This led to the suggestion that the peak current density (J{sub P}) and valley current density (J{sub V}) of the tunnel junction were enhanced after irradiation or the peak current was shifted to higher concentration. The recovery of the radiation damage under concentrated light illumination conditions suggests that the performance of the InGaP/GaAs tandem solar cell can be enhanced even under low concentration ratios.

  5. Polycrystalline GaAs solar cells on low-cost Silicon-Film{trademark} substrates

    SciTech Connect (OSTI)

    Mauk, M.G.; Feyock, B.W.; Hall, R.B.; Cavanaugh, K.D.; Cotter, J.E.

    1997-12-31

    The authors assess the potential of a low-cost, large-area Silicon-Film{trademark} sheet as a substrate for thin-film polycrystalline GaAs solar cells. Silicon-Film is a relatively inexpensive material on which large-grain (>2 mm) polycrystalline GaAs films can be formed. The GaAs epitaxial layers are grown by a simple close-spaced vapor transport (CSVT) technique using water vapor as a transport agent. A recrystallized Ge{sub 1{minus}x}Si{sub x} buffer layer between the GaAs epilayer and Silicon-Film substrate can facilitate growth of the GaAs. Selective epitaxy on patterned, oxide-masked substrates is effective in reducing thermal stress effects.

  6. MOCVD growth of GaAs solar cells on silicon substrates

    SciTech Connect (OSTI)

    Vernon, S.M.; Haven, V.E.; Geoffroy, L.M.; Sanfacon, M.M.; Mastrovito, A.L. )

    1992-12-01

    This paper reports advances in the development of solar cells made from GaAs-on-Si structures prepared by metalorganic chemical vapor deposition (MOCVD). The use of concentrator cells, operating at [similar to]200 suns, has led to the efficiency achievements of 21.3% (AM1.5D) for a GaAs-on-Si solar cell, and 27.6 (AM1.5D) for a homoepitaxial GaAs cell. The development of epitaxial multilayer dielectric mirrors (Bragg reflectors), as back-surface reflectors in thin-film GaAs cells, on both Si and GaAs substrates, is shown to lead to modest efficiency increases, over that of conventional designs.

  7. Doping of GaN{sub 1-x}As{sub x} with high As content

    SciTech Connect (OSTI)

    Levander, A.X.; Novikov, S.V.; Liliental-Weber, Z.; dos Reis, R.; Dubon, O.D.; Wu, J.; Foxon, C.T.; Yu, K.M.; Walukiewicz, W.

    2011-09-22

    Recent work has shown that GaN{sub 1-x}As{sub x} can be grown across the entire composition range by low temperature molecular beam epitaxy with intermediate compositions being amorphous, but control of the electrical properties through doping is critical for functionalizing this material. Here we report the bipolar doping of GaN{sub 1-x}As{sub x} with high As content to conductivities above 4 S/cm at room temperature using Mg or Te. The carrier type was confirmed by thermopower measurements. Doping requires an increase in Ga flux during growth resulting in a mixed phase material of polycrystalline GaAs:N embedded in amorphous GaN{sub 1-x}As{sub x}.

  8. Numerical analysis for high-efficiency GaAs solar cells fabricated on Si substrates

    SciTech Connect (OSTI)

    Yamaguchi, M.; Amano, C.; Itoh, Y.

    1989-07-15

    This paper describes some recent developments in GaAs thin-film solar cells fabricated on Si substrates by metalorganic chemical vapor deposition and numerically analyzes them.GaAs solar cells with efficiency of more than 18% are successfully fabricated on Si substrates by reducing the dislocation density. Photovoltaic properties of GaAs/Si cells are analyzed by considering the effect of nonuniform dislocation distribution on recombination properties of GaAs thin films on Si substrates. Numerical analysis shows that the effect of majority-carrier trapping must be considered. High efficiency GaAs solar cells with total-area efficiency of over 20% on Si substrates can be realized if dislocation density can be reduced to less than 5/times/10/sup 5/ cm/sup /minus/2/.

  9. Enhanced photoelectrochemical responses of ZnO films through Ga and N codoping

    SciTech Connect (OSTI)

    Ahn, Kwang-Soon; Yan, Yanfa; Shet, Sudhakar; Deutsch, Todd; Turner, John; Al-Jassim, Mowafak

    2007-12-03

    We report on the crystallinity and photoelectrochemical (PEC) response of ZnO thin films codoped by Ga and N. The ZnO:(Ga,N) thin films were deposited by cosputtering at room temperature and followed by postannealing at 500 deg. C in air for 2 h. We found that ZnO:(Ga,N) thin films exhibited significantly enhanced crystallinity compared to ZnO doped solely with N at the same growth conditions. Furthermore, ZnO:(Ga,N) thin films exhibited enhanced N incorporation over ZnO doped solely with N at high temperatures. As a result, ZnO:(Ga,N) thin films achieved dramatically improved PEC response, compared to ZnO thin films doped solely with N at any conditions. Our results suggest a general way to improve PEC response for wide-band-gap oxides.

  10. Electron Traps Detected in p-type GaAsN Using Deep Level Transient Spectroscopy

    SciTech Connect (OSTI)

    Johnston, S.; Kurtz, S.; Friedman, D.; Ptak, A.; Ahrenkiel, R.; Crandall, R.

    2005-01-01

    The GaAsN alloy can have a band gap as small as 1.0 eV when the nitrogen composition is about 2%. Indium can also be added to the alloy to increase lattice matching to GaAs and Ge. These properties are advantageous for developing a highly-efficient, multi-junction solar cell. However, poor GaAsN cell properties, such as low open-circuit voltage, have led to inadequate performance. Deep-level transient spectroscopy of p-type GaAsN has identified an electron trap having an activation energy near 0.2 eV and a trap density of at least 1016 cm-3. This trap level appears with the addition of small amounts of nitrogen to GaAs, which also corresponds to an increased drop in open-circuit voltage.

  11. Intrinsic polarization control in rectangular GaN nanowire lasers

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

    Li, Changyi; Liu, Sheng; Luk, Ting S.; Figiel, Jeffrey J.; Brener, Igal; Brueck, S. R. J.; Wang, George T.

    2016-02-10

    In this study, we demonstrate intrinsic, linearly polarized lasing from single GaN nanowires using cross-sectional shape control. A two-step top-down fabrication approach was employed to create straight nanowires with controllable rectangular cross-sections. A clear lasing threshold of 444kW/cm2 and a narrow spectral line width of 0.16 nm were observed under optical pumping at room temperature, indicating the onset of lasing. The polarization was along the short dimension (y-direction) of the nanowire due to the higher transverse confinement factors for y-polarized transverse modes resulting from the rectangular nanowire cross-section. The results show that cross-sectioned shape control can enable inherent control overmore » the polarization of nanowire lasers without additional environment requirements, such as placement onto lossy substrates.« less

  12. Ferromagnetic (Ga,Mn)As nanostructures for spintronic applications

    SciTech Connect (OSTI)

    Wosinski, Tadeusz; Andrearczyk, Tomasz; Figielski, Tadeusz; Makosa, Andrzej; Wrobel, Jerzy; Sadowski, Janusz

    2013-12-04

    Magneto-resistive, cross-like nanostructures have been designed and fabricated by electron-beam lithography patterning and chemical etching from thin epitaxial layers of the ferromagnetic semiconductor (Ga,Mn)As. The nanostructures, composed of two perpendicular nanostripes crossing in the middle of their length, represent four-terminal devices, in which an electric current can be driven through any of the two nanostripes. In these devices, a novel magneto-resistive memory effect, related to a rearrangement of magnetic domain walls in the central part of the device, has been demonstrated. It consists in that the zero-field resistance of a nanostripe depends on the direction of previously applied magnetic field. The nanostructures can thus work as two-state devices providing basic elements of nonvolatile memory cells.

  13. Surface modification of multilayer graphene using Ga ion irradiation

    SciTech Connect (OSTI)

    Wang, Quan; Shao, Ying; Ge, Daohan; Ren, Naifei; Yang, Qizhi

    2015-04-28

    The effect of Ga ion irradiation intensity on the surface of multilayer graphene was examined. Using Raman spectroscopy, we determined that the irradiation caused defects in the crystal structure of graphene. The density of defects increased with the increase in dwell times. Furthermore, the strain induced by the irradiation changed the crystallite size and the distance between defects. These defects had the effect of doping the multilayer graphene and increasing its work function. The increase in work function was determined using contact potential difference measurements. The surface morphology of the multilayer graphene changed following irradiation as determined by atomic force microscopy. Additionally, the adhesion between the atomic force microscopy tip and sample increased further indicating that the irradiation had caused surface modification, important for devices that incorporate graphene.

  14. Minerals Technologies | Open Energy Information

    Open Energy Info (EERE)

    Technologies Jump to: navigation, search Name: Minerals Technologies Place: Bethlehem, PA Website: www.mineralstechnologies.com References: Minerals Technologies1 Information...

  15. High Impact Technology Hub- Results

    Broader source: Energy.gov [DOE]

    Highlights, outcomes and activities to support the adoption of High Impact Technologies. Technology Highlights preview early results from current technology demonstrations. Case Studies overview...

  16. Gerar Technology | Open Energy Information

    Open Energy Info (EERE)

    Gerar Technology Jump to: navigation, search Name: Gerar Technology Place: Rio de Janeiro, Brazil Product: Developer of new technology for production of biodiesel from vegetable...

  17. EKB Technology | Open Energy Information

    Open Energy Info (EERE)

    EKB Technology Jump to: navigation, search Name: EKB Technology Place: Oxfordshire, United Kingdom Product: Developer of a new bioprocessing technology. Coordinates: 51.813938,...

  18. Rubicon Technology | Open Energy Information

    Open Energy Info (EERE)

    Rubicon Technology Jump to: navigation, search Name: Rubicon Technology Place: Franklin Park, Illinois Zip: 60131 Product: Rubicon Technology makes a sapphire substrates for use in...

  19. Shorepower Technologies | Open Energy Information

    Open Energy Info (EERE)

    Shorepower Technologies Jump to: navigation, search Logo: Shorepower Technologies Name: Shorepower Technologies Address: 2351 NW York St. Place: Portland, Oregon Zip: 97210 Region:...

  20. Briza Technologies | Open Energy Information

    Open Energy Info (EERE)

    Briza Technologies Jump to: navigation, search Name: Briza Technologies Place: Hillsborough, New Jersey Zip: 8844 Sector: Wind energy Product: Developing wind turbine technology....

  1. PCN Technology | Open Energy Information

    Open Energy Info (EERE)

    PCN Technology Jump to: navigation, search Name: PCN Technology Place: San Diego, California Zip: CA 92127 Product: California-based smart grid technology developer. References:...

  2. High Impact Technology HQ- Results

    Broader source: Energy.gov [DOE]

    Highlights, outcomes and activities to support the adoption of High Impact TechnologiesTechnology Highlights preview early results from current technology demonstrations.  Case Studies overview...

  3. Topanga Technologies | Open Energy Information

    Open Energy Info (EERE)

    Technologies Place: Canoga Park, California Zip: 91303 Product: Stealth-mode high-intensity discharge (HID) lighting technology developer. References: Topanga Technologies1...

  4. Konarka Technologies | Open Energy Information

    Open Energy Info (EERE)

    Technologies Jump to: navigation, search Name: Konarka Technologies Place: Lowell, MA Website: www.konarkatechnologies.com References: Konarka Technologies1 Information About...

  5. InGaAs monolithic interconnected modules (MIM)

    SciTech Connect (OSTI)

    Fatemi, N.S.; Jenkins, P.P.; Weizer, V.G.; Hoffman, R.W. Jr.; Wilt, D.M.; Scheiman, D.; Brinker, D.; Murray, C.S.; Riley, D.

    1997-12-31

    A monolithic interconnected module (MIM) structure has been developed for thermophotovoltaic (TPV) applications. The MIM device consists of many individual InGaAs cells series-connected on a single semi-insulating (S.I.) InP substrate. An infrared (IR) back surface reflector (BSR), placed on the rear surface of the substrate, returns the unused portion of the TPV radiator output spectrum back to the emitter for recycling, thereby providing for high system efficiencies. Also, the use of a BSR obviates the need to use a separate filtering element. As a result, MIMs are exposed to the entire emitter output, thereby maximizing output power density. MIMs with an active area of 1 x 1-cm were comprised of 15 cells monolithically connected in series. Both lattice-matched and lattice-mismatched InGaAs/InP devices were produced, with bandgaps of 0.74 and 0.55 eV, respectively. The 0.74-eV modules demonstrated an open-circuit voltage (Voc) of 6.158 V and a fill factor of 74.2% at a short-circuit current (Jsc) of 842 mA/cm{sup 2}, under flashlamp testing. The 0.55-eV modules demonstrated a Voc of 4.849 V and a fill factor of 57.8% at a Jsc of 3.87 A/cm{sup 2}. IR reflectance measurements (i.e., {lambda} > 2 {micro}m) of these devices indicated a reflectivity of {ge} 83%. Latest electrical and optical performance results for the MIMs will be presented.

  6. Technology transfer 1994

    SciTech Connect (OSTI)

    Not Available

    1994-01-01

    This document, Technology Transfer 94, is intended to communicate that there are many opportunities available to US industry and academic institutions to work with DOE and its laboratories and facilities in the vital activity of improving technology transfer to meet national needs. It has seven major sections: Introduction, Technology Transfer Activities, Access to Laboratories and Facilities, Laboratories and Facilities, DOE Office, Technologies, and an Index. Technology Transfer Activities highlights DOE`s recent developments in technology transfer and describes plans for the future. Access to Laboratories and Facilities describes the many avenues for cooperative interaction between DOE laboratories or facilities and industry, academia, and other government agencies. Laboratories and Facilities profiles the DOE laboratories and facilities involved in technology transfer and presents information on their missions, programs, expertise, facilities, and equipment, along with data on whom to contact for additional information on technology transfer. DOE Offices summarizes the major research and development programs within DOE. It also contains information on how to access DOE scientific and technical information. Technologies provides descriptions of some of the new technologies developed at DOE laboratories and facilities.

  7. Development of an IR-transparent, inverted-grown, thin-film, Al[sub 0. 34]Ga[sub 0. 66]As/GaAs cascade solar cell

    SciTech Connect (OSTI)

    Venkatasubramanian, R.; Timmons, M.L.; Sharps, P.R.; Colpitts, T.S.; Hills, J.S.; Hancock, J.; Hutchby, J.A. )

    1992-12-01

    Inverted growth and the development of associated cell processing, are likely to offer a significant degree of freedom for improving the performance of many III-V multijunction cascades and open new avenues for advanced multijunction concepts. This is especially true for the development of high-efficiency Al[sub 0.37]Ga[sub 0.63]As/GaAs cascades where the high growth temperatures required for the AlGaAs top cell growth can cause the deterioration of the tunnel junction interconnect. In the approach of inverted-grown AlGaAs/GaAs cascade cells, the AlGaAs top cell is grown first at 780 [degree]C and the GaAs tunnel junction and bottom cell are grown at 675 [degree]C. After the inverted growth, the AlGaAs/GaAs cascade structure is selectively removed from the parent substrate. The feasibility of inverted growth is demonstrated by a fully-processed, inverted-grown, thin film GaAs cell with a 1-sun AM1.5 efficiency of 20.3%. Also, an inverted-grown, thin-film, Al[sub 0.34]Ga[sub 0.66]As/GaAs cascade with AM1.5 efficiencies of 19.9% and 21% at 1-sun and 7-suns, respectively, has been obtained.

  8. Proceedings of the 12th Space Photovoltaic Research and Technology Conference (SPRAT 12)

    SciTech Connect (OSTI)

    1993-05-01

    The Twelfth Space Photovoltaic Research and Technology conference was held at the NASA Lewis Research Center from 20 to 22 Oct. 1992. The papers and workshops presented in this volume report substantial progress in a variety of areas in space photovoltaics. Topics covered include: high efficiency GaAs and InP solar cells, GaAs/Ge cells as commercial items, flexible amorphous and thin film solar cells (in the early stages of pilot production), high efficiency multiple bandgap cells, laser power converters, solar cell and array technology, heteroepitaxial cells, betavoltaic energy conversion, and space radiation effects in InP cells. Space flight data on a variety of cells were also presented. Separate abstracts have been prepared for articles from this report.

  9. Effects of phase transformation on the microstructures and magnetostriction of Fe-Ga and Fe-Ga-Zn ferromagnetic shape memory alloys

    SciTech Connect (OSTI)

    Lin, Yin-Chih Lin, Chien-Feng

    2015-05-07

    The phase transformation and magnetostriction of bulk Fe{sub 73}Ga{sub 27} and Fe{sub 73}Ga{sub 18}Zn{sub 9} (at.?%) ferromagnetic shape memory alloys (FSMs) were investigated by transmission electron microscopy (TEM), x-ray diffraction (XRD), and a magnetostrictive-meter setup. For the Fe{sub 73}Ga{sub 27} FSM alloy solution treated at 1100?C for 4?h and quenched in ice brine, the antiphase boundary segments of the D0{sub 3} domain were observed in the A2 (disordered) matrix, and the Fe{sub 73}Ga{sub 27} FSM alloy had an optimal magnetostriction (?{sub ?}{sup s?}=?71??10{sup ?6} and ?{sub ?}{sup s?}=??31??10{sup ?6}). In Fe{sub 73}Ga{sub 27} FSM alloy as-quenched, aged at 700?C for 24?h, and furnace cooled, D0{sub 3} nanoclusters underwent phase transformation to an intermediate tetragonal phase (i.e., L1{sub 0}-like martensite) via Bain distortion, and finally L1{sub 2} (Fe{sub 3}Ga) structures precipitated, as observed by TEM and XRD. The L1{sub 0}-like martensite and L1{sub 2} phases in the aged Fe{sub 73}Ga{sub 27} FSM alloy drastically decreased the magnetostriction from positive to negative (?{sub ?}{sup s?}=??20??10{sup ?6} and ?{sub ?}{sup s?}=??8??10{sup ?6}). However, in Fe{sub 73}Ga{sub 18}Zn{sub 9} FSM alloy as-quenched and aged, the phase transformation of D0{sub 3} to an intermediate tetragonal martensite phase and precipitation of L1{sub 2} structures were not found. The results indicate that the aged Fe{sub 73}Ga{sub 18}Zn{sub 9} FSM alloy maintained stable magnetostriction (?{sub ?}{sup s?}=?36??10{sup ?6} and ?{sub ?}{sup s?}=??31??10{sup ?6}). Adding Zn can improve the ferromagnetic shape memory effect of aged Fe{sub 73}Ga{sub 18}Zn{sub 9} alloy, which may be useful in application of the alloy in high temperature environments.

  10. Exploration Technologies Technology Needs Assessment | Department of Energy

    Office of Environmental Management (EM)

    Technologies Technology Needs Assessment Exploration Technologies Technology Needs Assessment The Exploration Technologies Needs Assessment is a critical component of ongoing technology roadmapping efforts, and will be used to guide the program's research and development. PDF icon iet_needs_assessment_06-2011.pdf More Documents & Publications Draft Innovative Exploration Technologies Needs Assessment Geothermal Technologies Program Annual Peer Review Presentation By Doug Hollett Hydrothermal

  11. Geothermal innovative technologies catalog

    SciTech Connect (OSTI)

    Kenkeremath, D.

    1988-09-01

    The technology items in this report were selected on the basis of technological readiness and applicability to current technology transfer thrusts. The items include technologies that are considered to be within 2 to 3 years of being transferred. While the catalog does not profess to be entirely complete, it does represent an initial attempt at archiving innovative geothermal technologies with ample room for additions as they occur. The catalog itself is divided into five major functional areas: Exploration; Drilling, Well Completion, and Reservoir Production; Materials and Brine Chemistry; Direct Use; and Economics. Within these major divisions are sub-categories identifying specific types of technological advances: Hardware; Software; Data Base; Process/Procedure; Test Facility; and Handbook.

  12. Building Technologies Office: Emerging Technologies Windows and Building Envelope

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

    Bahman Habibzadeh, PhD Technology Development Manger Building Technologies Office Emerging Technologies Windows and Building Envelope 2 Emerging Technologies (ET)  Develop cost-effective, high-impact building technologies: Lighting, HVAC, Windows & Envelope, Sensors & Controls, Appliances & Equipment Commercial Buildings Integration (CBI) Residential Buildings Integration (RBI)  Partner with private sector to demonstrate technologies and solutions  Demonstrate market

  13. Summary - Caustic Recovery Technology

    Office of Environmental Management (EM)

    Caustic Recovery Technology ETR Report Date: July 2007 ETR-7 United States Department of Energy Office of Environmental Management (DOE-EM) External Technical Review of Caustic Recovery Technology Why DOE-EM Did This Review The Department of Energy (DOE) Environmental Management Office (EM-21) has been developing caustic recovery technology for application to the Hanford Waste Treatment Plant (WTP) to reduce the amount of Low Activity Waste (LAW) vitrified. Recycle of sodium hydroxide with an

  14. Technology Transfer - JCAP

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

    PAZ0004_v2.jpg Technology Transfer Who We Are JCAP Mission JCAP At A Glance Fact Sheets Organizational Chart Recent Science Technology Transfer Awards & Honors Senior Management Scientific Leadership Researchers Governance & Advisory Boards Operations & Administration Who we are Overview JCAP Mission JCAP At A Glance Fact Sheets Organizational Chart Our Achievements Recent Science Technology Transfer Awards & Honors Our People Senior Management Scientific Leadership Researchers

  15. TECHNOLOGY READINESS ASSESSMENT

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

    ASSESSMENT JANUARY 2015 -A CHECKPOINT ALONG A CHALLENGING JOURNEY DOE/NETL-2015/1710 U.S. Department of Energy 2014 TECHNOLOGY READINESS ASSESSMENT-CLEAN COAL RESEARCH PROGRAM 2 2014 TECHNOLOGY READINESS ASSESSMENT-CLEAN COAL RESEARCH PROGRAM Office of Fossil Energy | National Energy Technology Laboratory DISCLAIMER 3 DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor

  16. Arc Position Sensing Technology

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

    Arc Position Sensing Technology Award Winning Technology Flaws in specialty metals used in aerospace and other advanced applications are often caused by solidification problems that arise during the melting and refining process. A common problem is arc constriction during melting. Previously, these conditions could not be identified during furnace operations, requiring ingot manufacturers to perform extensive testing on all ingots. The Arc Position Sensing (APS) technology, developed by NETL's

  17. Technology and energy supply

    Gasoline and Diesel Fuel Update (EIA)

    Donald L. Paul Executive Director, USC Energy Institute and William M. Keck Chair of Energy Resources 06 April 2010 EIA and SAIS 2010 Energy Conference Energy and the Economy Technology and Energy Transformation Science and Technology + Economics and Business + Society and Environment + Policy and Government Scale, time, and complexity 3 Existing supply and demand infrastructure New resources, infrastructures, and paradigms Multiple generations of technology History, the present, and the future

  18. Digital Sensor Technology

    SciTech Connect (OSTI)

    Ted Quinn; Jerry Mauck; Richard Bockhorst; Ken Thomas

    2013-07-01

    The nuclear industry has been slow to incorporate digital sensor technology into nuclear plant designs due to concerns with digital qualification issues. However, the benefits of digital sensor technology for nuclear plant instrumentation are substantial in terms of accuracy, reliability, availability, and maintainability. This report demonstrates these benefits in direct comparisons of digital and analog sensor applications. It also addresses the qualification issues that must be addressed in the application of digital sensor technology.

  19. Information Sciences and Technology

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

    Information Sciences and Technology Information Sciences and Technology National security depends on science and technology. The United States relies on Los Alamos National Laboratory for the best of both. No place on Earth pursues a broader array of world-class scientific endeavors. Contact thumbnail of Business Development Executive Steve Stringer Business Development Executive Richard P. Feynman Center for Innovation (505) 660-2177 Email Los Alamos leverages advances in theory, algorithms,

  20. NREL: Technology Transfer - Ombuds

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

    Technology Transfer Ombuds NREL's Technology Transfer Ombuds offers an informal process to help resolve issues and concerns regarding the laboratory's technology partnership, patent, and licensing activities. As a designated neutral party, our ombuds provides confidential, resolution-focused services. Through the ombuds process, we encourage collaborative techniques such as mediation to facilitate the speedy and low-cost resolution of complaints and disputes, when appropriate. The NREL Ombuds