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Sample records for germany gan m1

  1. M 1 Partners | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Partners Jump to: navigation, search Name: M-1 Partners Place: New York Product: M-1 Partners is a joint venture between Peter Marshall and Robert Ott with the objective of...

  2. Perseus (Germany) | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Perseus (Germany) Jump to: navigation, search Logo: Perseus (Germany) Name: Perseus (Germany) Address: Schumannstrasse 4 Place: Munich, Germany Zip: D-81679 Product: Private equity...

  3. Immosolar Germany | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Germany Jump to: navigation, search Logo: Immosolar Germany Name: Immosolar Germany Address: Valentinskamp 24 Place: Hamburg, Germany Sector: Solar Product: Solar energy systems...

  4. ARM - AMIE Gan Island - Data Plots

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Gan Related Links amie.png 34h AMIE Home cindy.png 50h CINDY2011 dynamo.png 34h DYNAMO ARM Data Discovery Browse Data Outreach News & Press Blog Backgrounder (PDF, 1.2MB) Education Flyer (PDF, 2.0MB) Images ARM flickr site Official AMIE Logo AMIE Gear Experiment Planning Steering Committee AMIE-MANUS Proposal Abstract AMIE-GAN Proposal Abstract Meetings Cloud Life Cycle Working Group Deployment Operations Science Plan - TWP Manus Site (PDF, 2.1 MB) Science Plan - Gan Island Site (PDF, 2.0

  5. ARM - News from the Gan Island Deployment

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    News from the Gan Island Deployment Related Links amie.png 34h AMIE Home cindy.png 50h CINDY2011 dynamo.png 34h DYNAMO ARM Data Discovery Browse Data Outreach News & Press Blog Backgrounder (PDF, 1.2MB) Education Flyer (PDF, 2.0MB) Images ARM flickr site Official AMIE Logo AMIE Gear Experiment Planning Steering Committee AMIE-MANUS Proposal Abstract AMIE-GAN Proposal Abstract Meetings Cloud Life Cycle Working Group Deployment Operations Science Plan - TWP Manus Site (PDF, 2.1 MB) Science

  6. GE Wind Energy Germany | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Energy Germany Jump to: navigation, search Name: GE Wind Energy Germany Place: Salzbergen, Germany Zip: 48499 Sector: Wind energy Product: Germany-based, division of GE Wind Energy...

  7. Enex Power Germany | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Power Germany Jump to: navigation, search Name: Enex Power Germany Place: Geretsried, Germany Sector: Geothermal energy Product: Germany-based subsidiary of Enex Power, developing...

  8. Observation of 690 MV m^-1 Electron Accelerating Gradient with...

    Office of Scientific and Technical Information (OSTI)

    Observation of 690 MV m-1 Electron Accelerating Gradient with a Laser-Driven Dielectric Microstructure Citation Details In-Document Search Title: Observation of 690 MV m-1...

  9. Greenpeace Energy Germany | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Greenpeace Energy Germany Jump to: navigation, search Name: Greenpeace Energy Germany Place: Hamburg, Germany Zip: 29357 Product: German sustainable energy provider Coordinates:...

  10. GaN: Defect and Device Issues

    SciTech Connect

    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.

  11. Germany: Energy Resources | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    276,000,000 Barrels (bbl) 54 2010 CIA World Factbook Energy Maps featuring Germany PV Solar Resource: U.S., Germany and Spain PV Solar Resource - US, Spain and Germany Germany...

  12. ARM - Field Campaign - AMIE-Gan Ancillary Disdrometer

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    would love to hear from you Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : AMIE-Gan Ancillary Disdrometer 2012.01.01 - 2012.02.10 Lead Scientist : Mariko Oue...

  13. Germany knows mining

    SciTech Connect

    2006-11-15

    Whether it is the nuance of precision or robust rock breaking strength, German suppliers have the expertise. Germany has about 120 companies in the mining equipment industry, employing some 16,000 people. The article describes some recent developments of the following companies: DBT, Liebherr, Atlas Copco, BASF, Boart Longyear, Eickhoff, IBS, Maschinenfabrik Glueckauf, Komatsu, TAKRA, Terex O & R, Thyssen Krupp Foerdertechnik and Wirtgen. 7 photos.

  14. AMIE Gan Island Ancillary Disdrometer Field Campaign Report (Program

    Office of Scientific and Technical Information (OSTI)

    Document) | SciTech Connect AMIE Gan Island Ancillary Disdrometer Field Campaign Report Citation Details In-Document Search Title: AMIE Gan Island Ancillary Disdrometer Field Campaign Report As part of the U.S. Department of Energy (DOE)'s Atmospheric Radiation Measurement Climate Research Facility (ARM) Madden-Julian Oscillation (MJO) Investigation Experiment (AMIE), in January 2012 a disdrometer observation took place with the second ARM Mobile Facility (AMF2), the Scanning ARM Cloud Radar

  15. ARM - VAP Product - visstpx08m1rv4minnis

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    8m1rv4minnis Documentation visst : XDC documentation Data Management Facility Plots (Quick Looks) ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send VAP Output : VISSTPX08M1RV4MINNIS VISST-derived pixel-level products from satellite MTSAT, version 4 Active Dates 2008.05.01 - 2008.12.31 Originating VAP Process Minnis Cloud Products Using Visst Algorithm : VISST Measurements The measurements below provided by this

  16. ARM MJO Investigation Experiment on Gan Island (AMIE-Gan) Science Plan

    SciTech Connect

    Long, CL; Del Genio, A; Deng, M; Fu, X; Gustafson, W; Houze, R; Jakob, C; Jensen, M; Johnson, R; Liu, X; Luke, E; May, P; McFarlane, S; Minnis, P; Schumacher, C; Vogelmann, A; Wang, Y; Webster, P; Xie, S; Zhang, C

    2011-04-11

    The overarching campaign, which includes the ARM Mobile Facility 2 (AMF2) deployment in conjunction with the Dynamics of the Madden-Julian Oscillation (DYNAMO) and the Cooperative Indian Ocean experiment on intraseasonal variability in the Year 2011 (CINDY2011) campaigns, is designed to test several current hypotheses regarding the mechanisms responsible for Madden-Julian Oscillation (MJO) initiation and propagation in the Indian Ocean area. The synergy between the proposed AMF2 deployment with DYNAMO/CINDY2011, and the corresponding funded experiment on Manus, combine for an overarching ARM MJO Investigation Experiment (AMIE) with two components: AMF2 on Gan Island in the Indian Ocean (AMIE-Gan), where the MJO initiates and starts its eastward propagation; and the ARM Manus site (AMIE-Manus), which is in the general area where the MJO usually starts to weaken in climate models. AMIE-Gan will provide measurements of particular interest to Atmospheric System Research (ASR) researchers relevant to improving the representation of MJO initiation in climate models. The framework of DYNAMO/CINDY2011 includes two proposed island-based sites and two ship-based locations forming a square pattern with sonde profiles and scanning precipitation and cloud radars at both island and ship sites. These data will be used to produce a Variational Analysis data set coinciding with the one produced for AMIE-Manus. The synergy between AMIE-Manus and AMIE-Gan will allow studies of the initiation, propagation, and evolution of the convective cloud population within the framework of the MJO. As with AMIE-Manus, AMIE-Gan/DYNAMO also includes a significant modeling component geared toward improving the representation of MJO initiation and propagation in climate and forecast models. This campaign involves the deployment of the second, marine-capable, AMF; all of the included measurement systems; and especially the scanning and vertically pointing radars. The campaign will include sonde

  17. 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...

  18. ARM - VAP Product - visstpx04m1rv3minnis

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    rv3minnis Documentation visst : XDC documentation Data Management Facility Plots (Quick Looks) ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send VAP Output : VISSTPX04M1RV3MINNIS VISST-derived pixel-level products from satellite MTSAT, version 3 Active Dates 2007.10.01 - 2007.12.31

  19. ARM - VAP Product - visstpx04m1rv4minnis

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    rv4minnis Documentation visst : XDC documentation Data Management Facility Plots (Quick Looks) ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send VAP Output : VISSTPX04M1RV4MINNIS VISST-derived pixel-level products from satellite MTSAT, version 4 Active Dates 2008.01.01 - 2008.04.30

  20. High Voltage GaN Schottky Rectifiers

    SciTech Connect

    CAO,X.A.; CHO,H.; CHU,S.N.G.; CHUO,C.-C.; CHYI,J.-I.; DANG,G.T.; HAN,JUNG; LEE,C.-M.; PEARTON,S.J.; REN,F.; WILSON,R.G.; ZHANG,A.P.

    1999-10-25

    Mesa and planar GaN Schottky diode rectifiers with reverse breakdown voltages (V{sub RB}) up to 550V and >2000V, respectively, have been fabricated. The on-state resistance, R{sub ON}, was 6m{Omega}{center_dot} cm{sup 2} and 0.8{Omega}cm{sup 2}, respectively, producing figure-of-merit values for (V{sub RB}){sup 2}/R{sub ON} in the range 5-48 MW{center_dot}cm{sup -2}. At low biases the reverse leakage current was proportional to the size of the rectifying contact perimeter, while at high biases the current was proportional to the area of this contact. These results suggest that at low reverse biases, the leakage is dominated by the surface component, while at higher biases the bulk component dominates. On-state voltages were 3.5V for the 550V diodes and {ge}15 for the 2kV diodes. Reverse recovery times were <0.2{micro}sec for devices switched from a forward current density of {approx}500A{center_dot}cm{sup -2} to a reverse bias of 100V.

  1. ARM - VAP Product - visstpx04m1rv1minnis

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    rv1minnis Documentation visst : XDC documentation Data Management Facility Plots (Quick Looks) ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send VAP Output : VISSTPX04M1RV1MINNIS VISST-derived pixel-level products from satellite MTSAT, version 1 Active Dates 2006.01.01 - 2006.02.28 Originating VAP Process Minnis Cloud Products Using Visst Algorithm : VISST Measurements The measurements below provided by this product

  2. Conductivity based on selective etch for GaN devices and applications thereof

    SciTech Connect

    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.

  3. Berlin, Germany: Energy Resources | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    in Berlin, Germany Ecologic Institute German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety Registered Energy Companies in Berlin, Germany 8KU...

  4. Germany Geothermal Region | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Germany Geothermal Region Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Germany Geothermal Region Details Areas (1) Power Plants (0) Projects (0) Techniques (0)...

  5. Highly transparent ammonothermal bulk GaN substrates

    SciTech Connect

    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.

  6. Ferromagnetism in undoped One-dimensional GaN Nanowires

    SciTech Connect

    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.

  7. Properties of H, O and C in GaN

    SciTech Connect

    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.

  8. Refractive index of erbium doped GaN thin films

    SciTech Connect

    Alajlouni, S.; Sun, Z. Y.; Li, J.; Lin, J. Y.; Jiang, H. X.; Zavada, J. M.

    2014-08-25

    GaN is an excellent host for erbium (Er) to provide optical emission in the technologically important as well as eye-safe 1540 nm wavelength window. Er doped GaN (GaN:Er) epilayers were synthesized on c-plane sapphire substrates using metal organic chemical vapor deposition. By employing a pulsed growth scheme, the crystalline quality of GaN:Er epilayers was significantly improved over those obtained by conventional growth method of continuous flow of reaction precursors. X-ray diffraction rocking curve linewidths of less than 300 arc sec were achieved for the GaN (0002) diffraction peak, which is comparable to the typical results of undoped high quality GaN epilayers and represents a major improvement over previously reported results for GaN:Er. Spectroscopic ellipsometry was used to determine the refractive index of the GaN:Er epilayers in the 1540 nm wavelength window and a linear dependence on Er concentration was found. The observed refractive index increase with Er incorporation and the improved crystalline quality of the GaN:Er epilayers indicate that low loss GaN:Er optical waveguiding structures are feasible.

  9. Structural defects in GaN revealed by Transmission Electron Microscopy

    DOE PAGES [OSTI]

    Liliental-Weber, Zuzanna

    2014-09-08

    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. Lastly, 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.

  10. Structural defects in GaN revealed by Transmission Electron Microscopy

    SciTech Connect

    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.

  11. Etelligence (Smart Grid Project) (Cuxhaven, Germany) | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    (Cuxhaven, Germany) Jump to: navigation, search Project Name Etelligence Country Germany Headquarters Location Cuxhaven, Germany Coordinates 53.861702, 8.694068 Loading map......

  12. EEnergy Project "MeRegio" (Smart Grid Project) (Freiamt, Germany...

    OpenEI (Open Energy Information) [EERE & EIA]

    Freiamt, Germany) Jump to: navigation, search Project Name EEnergy Project "MeRegio" Country Germany Headquarters Location Freiamt, Germany Coordinates 48.170155, 7.906666...

  13. EEnergy Project "MeRegio" (Smart Grid Project) (Ettenheim, Germany...

    OpenEI (Open Energy Information) [EERE & EIA]

    Ettenheim, Germany) Jump to: navigation, search Project Name EEnergy Project "MeRegio" Country Germany Headquarters Location Ettenheim, Germany Coordinates 48.252537, 7.813286...

  14. Westport Germany GmbH | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Jump to: navigation, search Name: Westport Germany GmbH Place: Germany Sector: Hydro, Hydrogen Product: Germany-based, regional office of Westport Innovations that develops and...

  15. Dislocation core structures in Si-doped GaN

    SciTech Connect

    Rhode, S. L. Fu, W. Y.; Sahonta, S.-L.; Kappers, M. J.; Humphreys, C. J.; Horton, M. K.; Pennycook, T. J.; Dusane, R. O.; Moram, M. A.

    2015-12-14

    Aberration-corrected scanning transmission electron microscopy was used to investigate the core structures of threading dislocations in plan-view geometry of GaN films with a range of Si-doping levels and dislocation densities ranging between (5 ± 1) × 10{sup 8} and (10 ± 1) × 10{sup 9} cm{sup −2}. All a-type (edge) dislocation core structures in all samples formed 5/7-atom ring core structures, whereas all (a + c)-type (mixed) dislocations formed either double 5/6-atom, dissociated 7/4/8/4/9-atom, or dissociated 7/4/8/4/8/4/9-atom core structures. This shows that Si-doping does not affect threading dislocation core structures in GaN. However, electron beam damage at 300 keV produces 4-atom ring structures for (a + c)-type cores in Si-doped GaN.

  16. Preparation and characterization of one-dimensional GaN nanorods with Tb intermediate layer

    SciTech Connect

    Shi, Feng; Xue, Chengshan

    2012-12-15

    Graphical abstract: Display Omitted Highlights: ► GaN nanorods have been prepared on Si substrates by magnetron sputtering. ► GaN nanorods are single crystal with hexagonal wurtzite structure. ► GaN nanorods are high-quality crystalline after ammoniating at 950 °C for 15 min. ► Ammoniating temperatures and times affect the growth of GaN nanorods significantly. -- Abstract: GaN nanorods have been successfully prepared on Si(1 1 1) substrates by magnetron sputtering through ammoniating Ga{sub 2}O{sub 3}/Tb thin films. X-ray diffraction (XRD), X-ray photoelectron spectroscope (XPS), FT-IR spectrophotometer, scanning electron microscope (SEM), high-resolution transmission electron microscope (HRTEM), and photoluminescence (PL) spectroscopy were used to characterize the microstructures, morphologies compositions and optical properties of the GaN samples. The results demonstrate that the nanorods are single crystal GaN with hexagonal wurtzite structure and high-quality crystalline after ammoniating at 950 °C for 15 min, which have the size of 100–150 nm in diameter. Ammoniating temperatures and times affect the growth of GaN nanorods significantly. The growth procedure mainly follows the Tb catalyst-assisted VLS mechanism.

  17. Germany

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power ...

  18. Bonn, Germany: Energy Resources | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Bonn, Germany: Energy Resources Jump to: navigation, search Equivalent URI DBpedia GeoNames ID 2946447 Coordinates 50.7327045, 7.0963113 Show Map Loading map......

  19. Cologne, Germany: Energy Resources | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Cologne, Germany: Energy Resources Jump to: navigation, search Equivalent URI DBpedia GeoNames ID 2886242 Coordinates 50.93333, 6.95 Show Map Loading map......

  20. Wilhelmshaven, Germany: Energy Resources | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Wilhelmshaven, Germany: Energy Resources Jump to: navigation, search Equivalent URI DBpedia GeoNames ID 2808720 Coordinates 53.517063, 8.119749 Show Map Loading map......

  1. Arnstadt, Germany: Energy Resources | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Arnstadt, Germany: Energy Resources Jump to: navigation, search Equivalent URI DBpedia GeoNames ID 2955439 Coordinates 50.83333, 10.95 Show Map Loading map......

  2. Hannover, Germany: Energy Resources | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Hannover, Germany: Energy Resources Jump to: navigation, search Equivalent URI DBpedia GeoNames ID 2910831 Coordinates 52.37052, 9.73322 Show Map Loading map......

  3. 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.

    DOEpatents

    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. Dislocation confinement in the growth of Na flux GaN on metalorganic...

    Office of Scientific and Technical Information (OSTI)

    Dislocation confinement in the growth of Na flux GaN on metalorganic chemical vapor deposition-GaN Citation Details In-Document Search Title: Dislocation confinement in the growth ...

  5. Growth and Band Offsets of Epitaxial Lanthanide Oxides on GaN...

    Office of Scientific and Technical Information (OSTI)

    M.T.T., 60 (6) (2012) 3 Jon Ihlefeld, Sandia National Laboratories Electronic Materials ... Undoped GaN Undoped AlGaN Doped AlGaN 2D Electron Gas Enhancement Mode (nominally ...

  6. Evolution of deep centers in GaN grown by hydride vapor phaseepitaxy

    SciTech Connect

    Fang, Z.-Q.; Look, D.C.; Jasinski, J.; Benamara, M.; Liliental-Weber, Z.; Molnar, R.J.

    2001-04-18

    Deep centers and dislocation densities in undoped n GaN, grown by hydride vapor phase epitaxy (HVPE), were characterized as a function of the layer thickness by deep level transient spectroscopy and transmission electron microscopy, respectively. As the layer thickness decreases, the variety and concentration of deep centers increase, in conjunction with the increase of dislocation density. Based on comparison with electron irradiation induced centers, some dominant centers in HVPE GaN are identified as possible point defects.

  7. Continuous and Dynamic Lasing Tuning of Single GaN Nanowires with

    Office of Scientific and Technical Information (OSTI)

    sub-nanometer resolution using Hydrostatic Pressure. (Conference) | SciTech Connect Continuous and Dynamic Lasing Tuning of Single GaN Nanowires with sub-nanometer resolution using Hydrostatic Pressure. Citation Details In-Document Search Title: Continuous and Dynamic Lasing Tuning of Single GaN Nanowires with sub-nanometer resolution using Hydrostatic Pressure. Abstract not provided. Authors: Liu, Sheng ; Brener, Igal ; Wang, George T. ; Li, Changyi ; Brueck, Steven R. J. Publication Date:

  8. Low temperature thin film transistors with hollow cathode plasma-assisted atomic layer deposition based GaN channels

    SciTech Connect

    Bolat, S. E-mail: aokyay@ee.bilkent.edu.tr; Tekcan, B.; Ozgit-Akgun, C.; Biyikli, N.; Okyay, A. K. E-mail: aokyay@ee.bilkent.edu.tr

    2014-06-16

    We report GaN thin film transistors (TFT) with a thermal budget below 250?C. GaN thin films are grown at 200?C by hollow cathode plasma-assisted atomic layer deposition (HCPA-ALD). HCPA-ALD-based GaN thin films are found to have a polycrystalline wurtzite structure with an average crystallite size of 9.3?nm. TFTs with bottom gate configuration are fabricated with HCPA-ALD grown GaN channel layers. Fabricated TFTs exhibit n-type field effect characteristics. N-channel GaN TFTs demonstrated on-to-off ratios (I{sub ON}/I{sub OFF}) of 10{sup 3} and sub-threshold swing of 3.3?V/decade. The entire TFT device fabrication process temperature is below 250?C, which is the lowest process temperature reported for GaN based transistors, so far.

  9. Hybrid device based on GaN nanoneedles and MEH-PPV/PEDOT:PSS polymer

    SciTech Connect

    Shin, Min Jeong; Gwon, Dong-Oh; Lee, Chan-Mi; Lee, Gang Seok; Jeon, In-Jun; Ahn, Hyung Soo; Yi, Sam Nyung; Ha, Dong Han

    2015-08-15

    Highlights: • A hybrid device was demonstrated by using MEH-PPV, PEDOT:PSS, and GaN nanoneedles. • I–V curve of the hybrid device showed its rectification behaviour, similar to a diode. • EL peak originated by the different potential barriers at MEH-PPV and GaN interface. - Abstract: A hybrid device that combines the properties of organic and inorganic semiconductors was fabricated and studied. It incorporated poly[2-methoxy-5-(2-ethylhexyloxy)- 1,4-phenylenevinylene] (MEH-PPV) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as organic polymers and GaN nanoneedles as an inorganic semiconductor. Layers of the two polymers were spin coated on to the GaN nanoneedles. The one peak in the electroluminescence spectrum originated from the MEH-PPV layer owing to the different potential barriers of electrons and holes at its interface with the GaN nanoneedles. However, the photoluminescence spectrum showed peaks due to both GaN nanoneedles and MEH-PPV. Such hybrid structures, suitably developed, might be able to improve the efficiency of optoelectronic devices.

  10. Intrinsic polarization control in rectangular GaN nanowire lasers

    DOE PAGES [OSTI]

    Li, Changyi; Liu, Sheng; Luk, Ting S.; Figiel, Jeffrey J.; Brener, Igal; Brueck, S. R. J.; Wang, George T.

    2016-02-01

    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

  11. Size dictated thermal conductivity of GaN

    DOE PAGES [OSTI]

    Thomas Edwin Beechem; McDonald, Anthony E.; Fuller, Elliot James; Talin, Albert Alec; Rost, Christina M.; Maria, Jon -Paul; Gaskins, John T.; Hopkins, Patrick E.; Allerman, Andrew A.

    2016-04-01

    The thermal conductivity on n- and p-type doped gallium nitride (GaN) epilayers having thickness of 3-4 μm was investigated using time domain thermoreflectance (TDTR). Despite possessing carrier concentrations ranging across 3 decades (1015 – 1018 cm–3), n-type layers exhibit a nearly constant thermal conductivity of 180 W/mK. The thermal conductivity of p-type epilayers, in contrast, reduces from 160 to 110 W/mK with increased doping. These trends–and their overall reduction relative to bulk–are explained leveraging established scattering models where it is shown that size effects play a primary role in limiting thermal conductivity for layers even tens of microns thick. GaNmore » device layers, even of pristine quality, will therefore exhibit thermal conductivities less than the bulk value of 240 W/mK owing to their finite thickness.« less

  12. EWIS European wind integration study (Smart Grid Project) (Germany...

    OpenEI (Open Energy Information) [EERE & EIA]

    Germany) Jump to: navigation, search Project Name EWIS European wind integration study Country Germany Coordinates 51.165691, 10.451526 Loading map... "minzoom":false,"mapping...

  13. High active nitrogen flux growth of GaN by plasma assisted molecular beam epitaxy

    SciTech Connect

    McSkimming, Brian M. Speck, James S.; Chaix, Catherine

    2015-09-15

    In the present study, the authors report on a modified Riber radio frequency (RF) nitrogen plasma source that provides active nitrogen fluxes more than 30 times higher than those commonly used for plasma assisted molecular beam epitaxy (PAMBE) growth of gallium nitride (GaN) and thus a significantly higher growth rate than has been previously reported. GaN films were grown using N{sub 2} gas flow rates between 5 and 25 sccm while varying the plasma source's RF forward power from 200 to 600 W. The highest growth rate, and therefore the highest active nitrogen flux, achieved was ∼7.6 μm/h. For optimized growth conditions, the surfaces displayed a clear step-terrace structure with an average RMS roughness (3 × 3 μm) on the order of 1 nm. Secondary ion mass spectroscopy impurity analysis demonstrates oxygen and hydrogen incorporation of 1 × 10{sup 16} and ∼5 × 10{sup 17}, respectively. In addition, the authors have achieved PAMBE growth of GaN at a substrate temperature more than 150 °C greater than our standard Ga rich GaN growth regime and ∼100 °C greater than any previously reported PAMBE growth of GaN. This growth temperature corresponds to GaN decomposition in vacuum of more than 20 nm/min; a regime previously unattainable with conventional nitrogen plasma sources. Arrhenius analysis of the decomposition rate shows that samples with a flux ratio below stoichiometry have an activation energy greater than decomposition of GaN in vacuum while samples grown at or above stoichiometry have decreased activation energy. The activation energy of decomposition for GaN in vacuum was previously determined to be ∼3.1 eV. For a Ga/N flux ratio of ∼1.5, this activation energy was found to be ∼2.8 eV, while for a Ga/N flux ratio of ∼0.5, it was found to be ∼7.9 eV.

  14. Towards Revised Step IV MICE Optics in the Absence of M1 SSD

    SciTech Connect

    Bayes, R.; Berg, J. S.; Blackmore, V.; Hunt, C.; Liu, A.; Pasternak, J.; Rogers, C. T.

    2015-10-01

    During magnet commissioning in September 2015, the leads on coil M1 of the downstream spectrometer solenoid failed. The coil will not be operational for MICE Step IV. Revised optics settings for the Step IV data taking are reviewed.

  15. GaN Initiative for Grid Applications (GIGA)

    SciTech Connect

    Turner, George

    2015-07-03

    For nearly 4 ½ 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 μm, 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

  16. Hamburg, Germany: Energy Resources | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Hamburg, Germany: Energy Resources Jump to: navigation, search Equivalent URI DBpedia GeoNames ID 2911298 Coordinates 53.55, 10 Show Map Loading map... "minzoom":false,"mappin...

  17. Munich, Germany: Energy Resources | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Energy Companies in Munich, Germany ACTANOL Service Ltd Allianz Climate Solutions ACS GmbH Amann GmbH BMW BayWa Group Centrosolar Group AG FutureCamp GmBH Mepsolar AG aka...

  18. Nanostructural engineering of nitride nucleation layers for GaN substrate dislocation reduction.

    SciTech Connect

    Koleske, Daniel David; Lee, Stephen Roger; Lemp, Thomas Kerr; Coltrin, Michael Elliott; Cross, Karen Charlene; Thaler, Gerald

    2009-07-01

    With no lattice matched substrate available, sapphire continues as the substrate of choice for GaN growth, because of its reasonable cost and the extensive prior experience using it as a substrate for GaN. Surprisingly, the high dislocation density does not appear to limit UV and blue LED light intensity. However, dislocations may limit green LED light intensity and LED lifetime, especially as LEDs are pushed to higher current density for high end solid state lighting sources. To improve the performance for these higher current density LEDs, simple growth-enabled reductions in dislocation density would be highly prized. GaN nucleation layers (NLs) are not commonly thought of as an application of nano-structural engineering; yet, these layers evolve during the growth process to produce self-assembled, nanometer-scale structures. Continued growth on these nuclei ultimately leads to a fully coalesced film, and we show in this research program that their initial density is correlated to the GaN dislocation density. In this 18 month program, we developed MOCVD growth methods to reduce GaN dislocation densities on sapphire from 5 x 10{sup 8} cm{sup -2} using our standard delay recovery growth technique to 1 x 10{sup 8} cm{sup -2} using an ultra-low nucleation density technique. For this research, we firmly established a correlation between the GaN nucleation thickness, the resulting nucleation density after annealing, and dislocation density of full GaN films grown on these nucleation layers. We developed methods to reduce the nuclei density while still maintaining the ability to fully coalesce the GaN films. Ways were sought to improve the GaN nuclei orientation by improving the sapphire surface smoothness by annealing prior to the NL growth. Methods to eliminate the formation of additional nuclei once the majority of GaN nuclei were developed using a silicon nitride treatment prior to the deposition of the nucleation layer. Nucleation layer thickness was determined

  19. Mission hazard assessment for STARS Mission 1 (M1) in the Marshall Islands area

    SciTech Connect

    Outka, D.E.; LaFarge, R.A.

    1993-07-01

    A mission hazard assessment has been performed for the Strategic Target System Mission 1 (known as STARS M1) for hazards due to potential debris impact in the Marshall Islands area. The work was performed at Sandia National Laboratories as a result of discussion with Kwajalein Missile Range (KMR) safety officers. The STARS M1 rocket will be launched from the Kauai Test Facility (KTF), Hawaii, and deliver two payloads to within the viewing range of sensors located on the Kwajalein Atoll. The purpose of this work has been to estimate upper bounds for expected casualty rates and impact probability or the Marshall Islands areas which adjoin the STARS M1 instantaneous impact point (IIP) trace. This report documents the methodology and results of the analysis.

  20. E1 and M1 γ-strength functions in 144Nd

    DOE PAGES [OSTI]

    Voinov, A. V.; Grimes, S. M.

    2015-12-14

    Both E1 and M1 γ-strength functions below the neutron separation energy were analyzed based on experimental data from 143Nd(n,γ)144Nd and 143Nd(n,γα)140Ce reactions. It is confirmed that the commonly adopted E1 model based on the temperature dependence of the width of the giant dipole resonance works well. The popular M1 strength function due to the spin-flip magnetic resonance located near the neutron binding energy is not capable of reproducing experimental data. As a result, the low-energy enhancement of the M1 strength or the energy-independent model of Weisskopf, both leading to the low-energy strength sizable to E1 one, fit experimental data best.

  1. Synthesis, morphology and optical properties of GaN and AlGaN semiconductor nanostructures

    SciTech Connect

    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.

  2. Provisions for containment venting in Germany

    SciTech Connect

    Wilhelm, J.G.

    1997-08-01

    In this short paper an overlook is given of the systems developed in Germany for filtered containment venting and their implementation in nuclear power plants. More information on the development can be found in the Proceedings of the DOE/NRC Aircleaning Conferences. In Germany, 28.8 % of the electric energy is produced by 19 nuclear power reactors. No new power reactor is expected to be built at least within the next ten years, but France and Germany cooperate in the development of a future European Power Reactor (ERP). This reactor type will be fitted with a core catcher and passive cooling in order to avoid serious consequences of a hypothetical core meltdown accident so that provisions for containment venting are not required. 3 refs., 6 figs., 1 tab.

  3. Electrical and optical properties of carbon-doped GaN grown by MBE on MOCVD GaN templates using a CCl4 dopant source

    SciTech Connect

    Armitage, Rob; Yang, Qing; Feick, Henning; Park, Yeonjoon; Weber, Eicke R.

    2002-04-15

    Carbon-doped GaN was grown by plasma-assisted molecular-beam epitaxy using carbon tetrachloride vapor as the dopant source. For moderate doping mainly acceptors were formed, yielding semi-insulating GaN. However at higher concentrations p-type conductivity was not observed, and heavily doped films (>5 x 10{sup 20} cm{sup -3}) were actually n-type rather than semi-insulating. Photoluminescence measurements showed two broad luminescence bands centered at 2.2 and 2.9 eV. The intensity of both bands increased with carbon content, but the 2.2 eV band dominated in n-type samples. Intense, narrow ({approx}6 meV) donor-bound exciton peaks were observed in the semi-insulating samples.

  4. EDeMa (Smart Grid Project) (Krefeld, Germany) | Open Energy Informatio...

    OpenEI (Open Energy Information) [EERE & EIA]

    (Krefeld, Germany) Jump to: navigation, search Project Name EDeMa Country Germany Headquarters Location Krefeld, Germany Coordinates 50.652943, 6.339111 Loading map......

  5. New probe of M1 and E1 strengths in GDR regions

    SciTech Connect

    Hayakawa, T. [Japan Atomic Energy Agency and National Astronomical Observatory in Japan (Japan); Ogata, K. [RCNP, Osaka University (Japan); Miyamoto, S.; Mochizuki, T.; Horikawa, K.; Amano, S. [University of Hyogo (Japan); Imazaki, K.; Li, D.; Izawa, Y. [Institute for Laser Technology (Japan); Chiba, S. [Tokyo Institute of Technology (Japan)

    2014-05-02

    The M1 strengths (or level density of 1{sup +} states) are of importance for estimation of interaction strengths between neutrinos and nuclei for the study of the supernova neutrino-process. In 1957, Agodi predicted theoretically angular distribution of neutrons emitted from states excited via dipole transitions with linearly polarized gamma-ray beam at the polar angle of ?=90 should be followed by a simple function, a + b cos(2?), where ?, is azimuthal angel. However, this theoretical prediction has not been verified over the wide mass region except for light nuclei as deuteron. We have measured neutron angular distributions with (polarized gamma, n) reactions on Au, Nal, and Cu. We have verified the Agodi's prediction for the first time over the wide mass region. This suggests that (polarized gamma, n) reactions may be useful tools to study M1 strengths in giant resonance regions.

  6. u.s. DEPARIMENT OF ENERGY EERE PROJECT M~'1AGEMENT CENTER

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    DEPARIMENT OF ENERGY EERE PROJECT M~'1AGEMENT CENTER NEPA Dl!IERMINATION RECIPIENT :long Island Power Authority PROJECT TITLE: Long Island 50 MW Solar Initiative Page 1 of2 STATE: NY Funding Opportunity Announcement Number Procurement lostrument Number NEPA Control Number CID Number OE* EEOOO3169 GF0-0003169-001 GOO Based on my review ofthe information conceming the proposed actlon,.5 NEPA Compliance Officer (authorized under DOE Order 451.1A), I have made the following determination: ex, EA,

  7. Tunnel-injection GaN quantum dot ultraviolet light-emitting diodes

    SciTech Connect

    Verma, Jai; Kandaswamy, Prem Kumar; Protasenko, Vladimir; Verma, Amit; Grace Xing, Huili; Jena, Debdeep

    2013-01-28

    We demonstrate a GaN quantum dot ultraviolet light-emitting diode that uses tunnel injection of carriers through AlN barriers into the active region. The quantum dot heterostructure is grown by molecular beam epitaxy on AlN templates. The large lattice mismatch between GaN and AlN favors the formation of GaN quantum dots in the Stranski-Krastanov growth mode. Carrier injection by tunneling can mitigate losses incurred in hot-carrier injection in light emitting heterostructures. To achieve tunnel injection, relatively low composition AlGaN is used for n- and p-type layers to simultaneously take advantage of effective band alignment and efficient doping. The small height of the quantum dots results in short-wavelength emission and are simultaneously an effective tool to fight the reduction of oscillator strength from quantum-confined Stark effect due to polarization fields. The strong quantum confinement results in room-temperature electroluminescence peaks at 261 and 340 nm, well above the 365 nm bandgap of bulk GaN. The demonstration opens the doorway to exploit many varied features of quantum dot physics to realize high-efficiency short-wavelength light sources.

  8. Surface Termination of M1 Phase and Rational Design of Propane Ammoxidation Catalysts

    SciTech Connect

    Guliants, Vadim

    2015-02-16

    This final report describes major accomplishments in this research project which has demonstrated that the M1 phase is the only crystalline phase required for propane ammoxidation to acrylonitrile and that a surface monolayer terminating the ab planes of the M1 phase is responsible for their activity and selectivity in this reaction. Fundamental studies of the topmost surface chemistry and mechanism of propane ammoxidation over the Mo-V-(Te,Sb)-(Nb,Ta)-O M1 and M2 phases resulted in the development of quantitative understanding of the surface molecular structure – reactivity relationships for this unique catalytic system. These oxides possess unique catalytic properties among mixed metal oxides, because they selectively catalyze three alkane transformation reactions, namely propane ammoxidation to acrylonitrile, propane oxidation to acrylic acid and ethane oxidative dehydrogenation, all of considerable economic significance. Therefore, the larger goal of this research was to expand this catalysis to other alkanes of commercial interest, and more broadly, demonstrate successful approaches to rational design of improved catalysts that can be applied to other selective (amm)oxidation processes.

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

    SciTech Connect

    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

  10. EM Gains Insight from Germany on Salt-Based Repositories | Department...

    Energy.gov [DOE] (indexed site)

    Participants in the workshops in Germany toured Asse II, one of Germanys two ... Participants in the workshops in Germany toured Asse II, one of Germany's two salt-based ...

  11. Microstructures of GaN and In{sub x}Ga{sub 1-x}N films grown by MOCVD on free-standing GaN templates

    SciTech Connect

    Jasinski, J.; Liliental-Weber, Z.; Huang, D.; Reshchikov, M.A.; Yun, F.; Morkoc, H.; Sone, C.; Park, S.S.; Lee, K.Y.

    2002-04-30

    We summarize structural properties of thick HVPE GaN templates from the point of view of their application as substrates for growth of nitride layers. This is followed by the results of optical and structural studies, mostly transmission electron microscopy, of nitride layers grown by MOCVD on top of the HVPE substrates. The results indicate high structural quality of these layers with a low density of threading dislocations (in the range of 10{sup 6} cm{sup -2}). Convergent beam electron diffraction studies showed that the MOCVD GaN films have Ga-polarity, the same polarity as the HVPE GaN substrates. Structural studies of an InGaN layer grown on top of the MOCVD GaN film showed the presence of two layers, which differed in lattice parameter and composition. The upper layer, on the top of the structure had a c-lattice parameter about 2% larger than that of GaN and contained 10.3 {+-} 0.8% of In. Values measured for the thinner, intermediate layer adjacent to the GaN layer were about 2 .5 times lower.

  12. Influence of growth temperature and temperature ramps on deep level defect incorporation in m-plane GaN

    SciTech Connect

    Armstrong, A. M.; Kelchner, K.; Nakamura, S.; DenBaars, S. P.; Materials Department, University of California, Santa Barbara, California 93106 ; Speck, J. S.

    2013-12-02

    The dependence of deep level defect incorporation in m-plane GaN films grown by metal-organic chemical vapor deposition on bulk m-plane GaN substrates as a function of growth temperature (T{sub g}) and T{sub g} ramping method was investigated using deep level optical spectroscopy. Understanding the influence of T{sub g} on GaN deep level incorporation is important for InGaN/GaN multi-quantum well (MQW) light emitting diodes (LEDs) and laser diodes (LDs) because GaN quantum barrier (QB) layers are grown much colder than thin film GaN to accommodate InGaN QW growth. Deep level spectra of low T{sub g} (800?C) GaN films grown under QB conditions were compared to deep level spectra of high T{sub g} (1150?C) GaN. Reducing T{sub g}, increased the defect density significantly (>50) through introduction of emergent deep level defects at 2.09?eV and 2.9?eV below the conduction band minimum. However, optimizing growth conditions during the temperature ramp when transitioning from high to low T{sub g} substantially reduced the density of these emergent deep levels by approximately 40%. The results suggest that it is important to consider the potential for non-radiative recombination in QBs of LED or LD active regions, and tailoring the transition from high T{sub g} GaN growth to active layer growth can mitigate such non-radiative channels.

  13. Localized tip enhanced Raman spectroscopic study of impurity incorporated single GaN nanowire in the sub-diffraction limit

    SciTech Connect

    Patsha, Avinash E-mail: dhara@igcar.gov.in; Dhara, Sandip; Tyagi, A. K.

    2015-09-21

    The localized effect of impurities in single GaN nanowires in the sub-diffraction limit is reported using the study of lattice vibrational modes in the evanescent field of Au nanoparticle assisted tip enhanced Raman spectroscopy (TERS). GaN nanowires with the O impurity and the Mg dopants were grown by the chemical vapor deposition technique in the catalyst assisted vapor-liquid-solid process. Symmetry allowed Raman modes of wurtzite GaN are observed for undoped and doped nanowires. Unusually very strong intensity of the non-zone center zone boundary mode is observed for the TERS studies of both the undoped and the Mg doped GaN single nanowires. Surface optical mode of A{sub 1} symmetry is also observed for both the undoped and the Mg doped GaN samples. A strong coupling of longitudinal optical (LO) phonons with free electrons, however, is reported only in the O rich single nanowires with the asymmetric A{sub 1}(LO) mode. Study of the local vibration mode shows the presence of Mg as dopant in the single GaN nanowires.

  14. Energy R and D in Germany

    SciTech Connect

    Runci, PJ

    1999-11-01

    Germany's total national (i.e., combined public and private sector) funding for R&D stood at $42 billion in 1997. The private sector accounted for nearly 62% ($24 billion) of the total, while the public sector accounted for approximately 38%. Since the late 1970s, when the public and private sectors each funded roughly half of Germany's R&D, the private sector has steadily assumed a larger and larger role as the dominant supporter of R&D activity, while overall government funding has remained essentially flat for much of the past two decades. In addition to declining relative to private R&D expenditures, public R&D expenditures in Germany declined by 4% in real terms between 1991 and 1997, to approximately $15 billion. The reduction in R&D investments in the public sector can be attributed in large part to the financial challenges associated with German reunification and related shifts in social priorities including efforts to address high unemployment and to rebuild basic infrastructure in the eastern states. R&D expenditures have also declined as a percentage of the total public budget, from a peak of 3.4% in 1985 to 2.7% in 1996. Energy R&D has been the hardest hit of all major socioeconomic areas of R&D expenditure funded by the German government. Between 1981 and 1997, public energy R&D fell from approximately $1.6 billion to $400 million--a 75% real decline. The $850 million reduction in Germany's fission R&D budget (which constituted two-thirds of government R&D investment in 1985) explains some 90% of the funding decline. Negative public perceptions regarding the safety and environmental impacts of nuclear energy have reduced nuclear power's viability as a long-term energy option for Germany. Discussions of a complete nuclear phaseout are now under way. At the same time, the German government has slashed its investments in fossil energy R&D by more than 90%. While energy efficiency and renewable energy technologies have fared relatively well in comparison

  15. Performance and breakdown characteristics of irradiated vertical power GaN P-i-N diodes

    DOE PAGES [OSTI]

    King, M. P.; Armstrong, A. M.; Dickerson, J. R.; Vizkelethy, G.; Fleming, R. M.; Campbell, J.; Wampler, W. R.; Kizilyalli, I. C.; Bour, D. P.; Aktas, O.; et al

    2015-10-29

    Electrical performance and defect characterization of vertical GaN P-i-N diodes before and after irradiation with 2.5 MeV protons and neutrons is investigated. Devices exhibit increase in specific on-resistance following irradiation with protons and neutrons, indicating displacement damage introduces defects into the p-GaN and n- drift regions of the device that impact on-state device performance. The breakdown voltage of these devices, initially above 1700 V, is observed to decrease only slightly for particle fluence <; 1013 cm-2. Furthermore, the unipolar figure of merit for power devices indicates that while the on-resistance and breakdown voltage degrade with irradiation, vertical GaN P-i-Ns remainmore » superior to the performance of the best available, unirradiated silicon devices and on-par with unirradiated modern SiC-based power devices.« less

  16. Anisotropy of two-photon absorption and free-carrier effect in nonpolar GaN

    SciTech Connect

    Fang, Yu; Zhou, Feng; Yang, Junyi; Wu, Xingzhi; Xiao, Zhengguo; Li, Zhongguo; Song, Yinglin

    2015-03-30

    We reported a systematic study about the anisotropic optical nonlinearities in bulk m-plane and a-plane GaN crystals by Z-scan and pump-probe with phase object methods under picosecond at 532 nm. The two-photon absorption coefficient, which was measured as a function of polarization angle, exhibited oscillation curves with a period of π/2, indicating a highly polarized optical third-order nonlinearity in both nonpolar GaN samples. Furthermore, free-carrier absorption revealed stronger hole-related absorption for E⊥c than for E//c probe polarization. In contrast, free-carrier refraction was found almost isotropic due to electron-related refraction in the isotropic conduction bands.

  17. High voltage and high current density vertical GaN power diodes

    SciTech Connect

    Fischer, A. J.; Dickerson, J. R.; Armstrong, A. M.; Moseley, M. W.; Crawford, M. H.; King, M. P.; Allerman, A. A.; Kaplar, R. J.; van Heukelom, M. S.; Wierer, J. J.

    2016-01-01

    We report on the realization of a GaN high voltage vertical p-n diode operating at > 3.9 kV breakdown with a specific on-resistance < 0.9 mΩ.cm2. Diodes achieved a forward current of 1 A for on-wafer, DC measurements, corresponding to a current density > 1.4 kA/cm2. An effective critical electric field of 3.9 MV/cm was estimated for the devices from analysis of the forward and reverse current-voltage characteristics. Furthermore this suggests that the fundamental limit to the GaN critical electric field is significantly greater than previously believed.

  18. High voltage and high current density vertical GaN power diodes

    DOE PAGES [OSTI]

    Fischer, A. J.; Dickerson, J. R.; Armstrong, A. M.; Moseley, M. W.; Crawford, M. H.; King, M. P.; Allerman, A. A.; Kaplar, R. J.; van Heukelom, M. S.; Wierer, J. J.

    2016-01-01

    We report on the realization of a GaN high voltage vertical p-n diode operating at > 3.9 kV breakdown with a specific on-resistance < 0.9 mΩ.cm2. Diodes achieved a forward current of 1 A for on-wafer, DC measurements, corresponding to a current density > 1.4 kA/cm2. An effective critical electric field of 3.9 MV/cm was estimated for the devices from analysis of the forward and reverse current-voltage characteristics. Furthermore this suggests that the fundamental limit to the GaN critical electric field is significantly greater than previously believed.

  19. Surfactant assisted growth of MgO films on GaN

    SciTech Connect

    Paisley, E. A.; Shelton, T. C.; Collazo, R.; Sitar, Z.; Maria, J.-P.; Christen, H. M.; Biegalski, M. D.; Mita, S.

    2012-08-27

    Thin epitaxial films of <111> oriented MgO on [0001]-oriented GaN were grown by molecular beam epitaxy and pulsed laser deposition using the assistance of a vapor phase surfactant. In both cases, surfactant incorporation enabled layer-by-layer growth and a smooth terminal surface by stabilizing the {l_brace}111{r_brace} rocksalt facet. Metal-insulator-semiconductor capacitor structures were fabricated on n-type GaN. A comparison of leakage current density for conventional and surfactant-assisted growth reveals a nearly 100 Multiplication-Sign reduction in leakage current density for the surfactant-assisted samples. These data verify numerous predictions regarding the role of H-termination in regulating the habit of rocksalt crystals.

  20. Catalyst and its diameter dependent growth kinetics of CVD grown GaN nanowires

    SciTech Connect

    Samanta, Chandan [Department of Physics, Indian Institute of Technology Kanpur (India)] [Department of Physics, Indian Institute of Technology Kanpur (India); Chander, D. Sathish [Department of Physics, Indian Institute of Technology Kanpur (India) [Department of Physics, Indian Institute of Technology Kanpur (India); Department of Mechanical Engineering, Indian Institute of Technology Kanpur (India); Ramkumar, J. [Department of Mechanical Engineering, Indian Institute of Technology Kanpur (India)] [Department of Mechanical Engineering, Indian Institute of Technology Kanpur (India); Dhamodaran, S., E-mail: kdams2003@gmail.com [Department of Physics, Indian Institute of Technology Kanpur (India)

    2012-04-15

    Graphical abstract: GaN nanowires with controlled diameter and aspect ratio has been grown using a simple CVD technique. The growth kinetics of CVD grown nanowires investigated in detail for different catalysts and their diameters. A critical diameter important to distinguish the growth regimes has been discussed in detail. The results are important which demonstrates the growth of diameter and aspect ratio controlled GaN nanowires and also understand their growth kinetics. Highlights: Black-Right-Pointing-Pointer Controlled diameter and aspect ratio of GaN nanowires achieved in simple CVD reactor. Black-Right-Pointing-Pointer Nanowire growth kinetics for different catalyst and its diameters were understood. Black-Right-Pointing-Pointer Adatoms vapor pressure inside reactor plays a crucial role in growth kinetics. Black-Right-Pointing-Pointer Diffusion along nanowire sidewalls dominate for gold and nickel catalysts. Black-Right-Pointing-Pointer Gibbs-Thomson effect dominates for palladium catalyst. -- Abstract: GaN nanowires were grown using chemical vapor deposition with controlled aspect ratio. The catalyst and catalyst-diameter dependent growth kinetics is investigated in detail. We first discuss gold catalyst diameter dependent growth kinetics and subsequently compare with nickel and palladium catalyst. For different diameters of gold catalyst there was hardly any variation in the length of the nanowires but for other catalysts with different diameter a strong length variation of the nanowires was observed. We calculated the critical diameter dependence on adatoms pressure inside the reactor and inside the catalytic particle. This gives an increasing trend in critical diameter as per the order gold, nickel and palladium for the current set of experimental conditions. Based on the critical diameter, with gold and nickel catalyst the nanowire growth was understood to be governed by limited surface diffusion of adatoms and by Gibbs-Thomson effect for the palladium

  1. Structure and electronic properties of mixed (a + c) dislocation cores in GaN

    SciTech Connect

    Horton, M. K.; Rhode, S. L.; Moram, M. A.

    2014-08-14

    Classical atomistic models and atomic-resolution scanning transmission electron microscopy studies of GaN films reveal that mixed (a + c)-type dislocations have multiple different core structures, including a dissociated structure consisting of a planar fault on one of the (12{sup ¯}10) planes terminated by two different partial dislocations. Density functional theory calculations show that all cores introduce localized states into the band gap, which affects device performance.

  2. Hafnium nitride buffer layers for growth of GaN on silicon

    DOEpatents

    Armitage, Robert D.; Weber, Eicke R.

    2005-08-16

    Gallium nitride is grown by plasma-assisted molecular-beam epitaxy on (111) and (001) silicon substrates using hafnium nitride buffer layers. Wurtzite GaN epitaxial layers are obtained on both the (111) and (001) HfN/Si surfaces, with crack-free thickness up to 1.2 {character pullout}m. However, growth on the (001) surface results in nearly stress-free films, suggesting that much thicker crack-free layers could be obtained.

  3. Space-and-time-resolved spectroscopy of single GaN nanowires

    SciTech Connect

    Upadhya, Prashanth C.; Martinez, Julio A.; Li, Qiming; Wang, George T.; Swartzentruber, Brian S.; Taylor, Antoinette J.; Prasankumar, Rohit P.

    2015-06-29

    Gallium nitride nanowires have garnered much attention in recent years due to their attractive optical and electrical properties. An understanding of carrier transport, relaxation, and recombination in these quasi-one-dimensional nanosystems is therefore important in optimizing them for various applications. Here, we present ultrafast optical microscopic measurements on single GaN nanowires. Our experiments, performed while varying the light polarization, excitation fluence, and position, give insight into the mechanisms governing carrier dynamics in these nanosystems.

  4. Vertical GaN power diodes with a bilayer edge termination

    SciTech Connect

    Dickerson, Jeramy R.; Allerman, Andrew A.; Bryant, Benjamin N.; Fischer, Arthur J.; King, Michael P.; Moseley, Michael W.; Armstrong, Andrew M.; Kaplar, Robert J.; Kizilyalli, Isik C.; Aktas, Ozgur; Wierer, Jr., Jonathan J.

    2015-12-07

    Vertical GaN power diodes with a bilayer edge termination (ET) are demonstrated. The GaN p-n junction is formed on a low threading dislocation defect density (104 - 105 cm-2) GaN substrate, and has a 15-μm-thick n-type drift layer with a free carrier concentration of 5 × 1015 cm-3. The ET structure is formed by N implantation into the p+-GaN epilayer just outside the p-type contact to create compensating defects. The implant defect profile may be approximated by a bilayer structure consisting of a fully compensated layer near the surface, followed by a 90% compensated (p) layer near the n-type drift region. These devices exhibit avalanche breakdown as high as 2.6 kV at room temperature. In addition simulations show that the ET created by implantation is an effective way to laterally distribute the electric field over a large area. This increases the voltage at which impact ionization occurs and leads to the observed higher breakdown voltages.

  5. Vertical GaN power diodes with a bilayer edge termination

    DOE PAGES [OSTI]

    Dickerson, Jeramy R.; Allerman, Andrew A.; Bryant, Benjamin N.; Fischer, Arthur J.; King, Michael P.; Moseley, Michael W.; Armstrong, Andrew M.; Kaplar, Robert J.; Kizilyalli, Isik C.; Aktas, Ozgur; et al

    2015-12-07

    Vertical GaN power diodes with a bilayer edge termination (ET) are demonstrated. The GaN p-n junction is formed on a low threading dislocation defect density (104 - 105 cm-2) GaN substrate, and has a 15-μm-thick n-type drift layer with a free carrier concentration of 5 × 1015 cm-3. The ET structure is formed by N implantation into the p+-GaN epilayer just outside the p-type contact to create compensating defects. The implant defect profile may be approximated by a bilayer structure consisting of a fully compensated layer near the surface, followed by a 90% compensated (p) layer near the n-type driftmore » region. These devices exhibit avalanche breakdown as high as 2.6 kV at room temperature. In addition simulations show that the ET created by implantation is an effective way to laterally distribute the electric field over a large area. This increases the voltage at which impact ionization occurs and leads to the observed higher breakdown voltages.« less

  6. Formation of manganese {delta}-doped atomic layer in wurtzite GaN

    SciTech Connect

    Shi Meng; Chinchore, Abhijit; Wang Kangkang; Mandru, Andrada-Oana; Liu Yinghao; Smith, Arthur R.

    2012-09-01

    We describe the formation of a {delta}-doped manganese layer embedded within c-plane wurtzite gallium nitride using a special molecular beam epitaxy growth process. Manganese is first deposited on the gallium-poor GaN (0001) surface, forming a {radical}(3) Multiplication-Sign {radical}(3)-R30 Degree-Sign reconstructed phase. This well-defined surface reconstruction is then nitrided using plasma nitridation, and gallium nitride is overgrown. The manganese content of the {radical}(3) Multiplication-Sign {radical}(3)-R30 Degree-Sign phase, namely one Mn per each {radical}(3) Multiplication-Sign {radical}(3)-R30 Degree-Sign unit cell, implies that the MnGaN alloy layer has a Mn concentration of up to 33%. The structure and chemical content of the surface are monitored beginning from the initial growth stage up through the overgrowth of 20 additional monolayers (MLs) of GaN. An exponential-like drop-off of the Mn signal with increasing GaN monolayers, as measured by Auger electron spectroscopy, indicates that the highly concentrated Mn layer remains at the {delta}-doped interface. A model of the resultant {delta}-doped structure is formulated based on the experimental data, and implications for possible spintronic applications are discussed.

  7. Theoretical and experimental study of dynamics of photoexcited carriers in GaN

    SciTech Connect

    Shishehchi, Sara; Bellotti, Enrico; Rudin, Sergey; Garrett, Gregory A.; Wraback, Michael

    2013-12-21

    We present a theoretical and experimental study of the sub-picosecond dynamics of photo-excited carriers in GaN. In the theoretical model, interaction with an external ultrafast laser pulse is treated coherently and to account for the scattering mechanisms and dephasing processes, a generalized Monte-Carlo simulation is used. The scattering mechanisms included are carrier interactions with polar optical phonons and acoustic phonons, and carrier-carrier Coulomb interactions. We study the effect of different scattering mechanisms on the carrier densities. In the case that the excitation energy satisfies the threshold for polar optical scattering, phonon contribution is the dominant process in relaxing the system, otherwise, carrier-carrier mechanism is dominant. Furthermore, we present the temperature and pulse power dependent normalized luminescence intensity. The results are presented over a range of temperatures, electric field, and excitation energy of the laser pulse. For comparison, we also report the experimental time-resolved photoluminescence studies on GaN samples. There is a good agreement between the simulation and experiment in normalized luminescence intensity results. Therefore, we show that we can explain the dynamics of the photo-excited carriers in GaN by including only carrier-carrier and carrier-phonon interactions and a relatively simple two-band electronic structure model.

  8. Analysis of the carbon-related 'blue' luminescence in GaN

    SciTech Connect

    Armitage, R.; Yang, Q.; Weber, E.R.

    2004-09-24

    The properties of a broad 2.86 eV photoluminescence band in carbon-doped GaN were studied as a function of C-doping level, temperature, and excitation density. The results are consistent with a C{sub Ga}-C{sub N} deep donor-deep acceptor recombination mechanism as proposed by Seager et al. For GaN:C grown by molecular-beam epitaxy (MBE) the 2.86 eV band is observed in Si co-doped layers exhibiting high n-type conductivity as well as in semi-insulating material. For low excitation density (4 W/cm{sup 2}) the 2.86 eV band intensity decreases as a function of cw-laser exposure time over a period of many minutes. The transient behavior is consistent with a model based on carrier diffusion and charge trapping-induced Coulomb barriers. The temperature dependence of the blue luminescence below 150 K was different for carbon-contaminated GaN grown by metalorganic vapor phase epitaxy (MOVPE) compared to C-doped MBE GaN.

  9. Low-energy electro- and photo-emission spectroscopy of GaN materials and devices

    SciTech Connect

    Piccardo, Marco; Weisbuch, Claude; Iveland, Justin; Nakamura, Shuji; Speck, James S.; Martinelli, Lucio Peretti, Jacques; Choi, Joo Won

    2015-03-21

    In hot-electron semiconductor devices, carrier transport extends over a wide range of conduction states, which often includes multiple satellite valleys. Electrical measurements can hardly give access to the transport processes over such a wide range without resorting to models and simulations. An alternative experimental approach however exists which is based on low-energy electron spectroscopy and provides, in a number of cases, very direct and selective information on hot-electron transport mechanisms. Recent results obtained in GaN crystals and devices by electron emission spectroscopy are discussed. Using near-band-gap photoemission, the energy position of the first satellite valley in wurtzite GaN is directly determined. By electro-emission spectroscopy, we show that the measurement of the electron spectrum emitted from a GaN p-n junction and InGaN/GaN light-emitting diodes (LEDs) under electrical injection of carriers provides a direct observation of transport processes in these devices. In particular, at high injected current density, high-energy features appear in the electro-emission spectrum of the LEDs showing that Auger electrons are being generated in the active region. These measurements allow us identifying the microscopic mechanism responsible for droop which represents a major hurdle for widespread adoption of solid-state lighting.

  10. Search for 14.4 keV solar axions from M1 transition of Fe-57...

    Office of Scientific and Technical Information (OSTI)

    Search for 14.4 keV solar axions from M1 transition of Fe-57 with CUORE crystals Citation Details In-Document Search Title: Search for 14.4 keV solar axions from M1 transition of...

  11. Discovery of low-lying E1 and M1 strengths in {sup 232}Th

    SciTech Connect

    Adekola, A. S.; Hammond, S. L.; Hill, A.; Karwowski, H. J.; Angell, C. T.; Howell, C. R.; Kwan, E.; Kelley, J. H.

    2011-03-15

    Properties of low-energy dipole states in {sup 232}Th have been investigated with the nuclear resonance fluorescence technique. The present work used monoenergetic {gamma}-ray beams at energies of 2-4 MeV from the high-intensity {gamma}-ray source at Triangle Universities Nuclear Laboratory. Over 40 transitions corresponding to deexcitation to the ground state and first excited state were observed for the first time. Excitation energies, integrated cross sections, decay widths, branching ratios, and transition strengths for those states in {sup 232}Th were determined and compared with quasiparticle random-phase-approximation calculations. A large number of E1 transitions were observed for the first time in actinide nuclei with summed strength of 3.28(69)x10{sup -3} e{sup 2} fm{sup 2}. The observed summed M1 strength of 4.26(63){mu}{sub N}{sup 2} is in good agreement with the other actinides and with the systematics of the scissors mode in deformed rare-earth nuclei.

  12. 2015 Wind Turbine Blade Manufacture Conference-Dusseldorf, Germany

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Wind Turbine Blade Manufacture Conference-Dusseldorf, Germany - Sandia Energy Energy ... Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power ...

  13. MHK Projects/Munich Germany SHP | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Munich Germany SHP < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP"...

  14. MHK Projects/Rosenheim Germany SHP | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Rosenheim Germany SHP < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","type":"ROADM...

  15. Spectroscopic and magnetic properties of Mn doped GaN epitaxial films grown by plasma assisted molecular beam epitaxy

    SciTech Connect

    Vidyasagar, R.; Lin, Y.-T.; Tu, L.-W.

    2012-12-15

    Graphical abstract: We report here that micro-Raman scattering spectrum for Mn doped GaN thin film has displayed a new peak manifested at 578 cm{sup −1}, by which it is attributed to interior LVM originated by the incorporation of Mn ions in place of Ga sites. Mn doped GaN thin film also showed the typical negative magnetoresistance up to ∼50 K, revealing that the film showed magnetic ordering of spins below 50 K. Display Omitted Highlights: ► GaN and Mn doped GaN single phase wurtzite structures grown by PAMBE. ► The phase purity of the epilayers investigated by HRXRD, HRSEM and EDX. ► The red shift in near band edge emission has been observed using micro-PL. ► A new peak related LVM at 578 cm{sup −1} in micro-Raman scattering measurements confirmed Mn doped into GaN. ► Negative-magnetoresistance investigations have showed that the film has T{sub c} < 50 K. -- Abstract: Spectroscopic and magnetic properties of Mn doped GaN, and GaN epitaxial films have been investigated by employing micro-photoluminescence, micro-Raman, and temperature dependent magneto-resistance measurements. The HR-XRD profiles have shown that the epitaxial films are in hexagonal wurtzite structures. Morphology and composition of the films have been examined by field emission scanning electron microscopy, and energy-dispersive X-ray analysis. Micro-photoluminescence spectrum displayed a dominant near band edge emission at 362 nm, which is assigned to near band edge transition within the hexagonal structure of GaN. Raman scattering profiles showed a new vibrational mode at 578 cm{sup −1}, which is attributed to the vacancy-related local vibrational mode of Mn occupying the Ga site. Temperature dependent negative magnetoresistance measurements provide a direct evidence of magnetic ordering below 50 K for the Mn doped GaN thin film.

  16. Origins of low energy-transfer efficiency between patterned GaN quantum well and CdSe quantum dots

    SciTech Connect

    Xu, Xingsheng

    2015-03-02

    For hybrid light emitting devices (LEDs) consisting of GaN quantum wells and colloidal quantum dots, it is necessary to explore the physical mechanisms causing decreases in the quantum efficiencies and the energy transfer efficiency between a GaN quantum well and CdSe quantum dots. This study investigated the electro-luminescence for a hybrid LED consisting of colloidal quantum dots and a GaN quantum well patterned with photonic crystals. It was found that both the quantum efficiency of colloidal quantum dots on a GaN quantum well and the energy transfer efficiency between the patterned GaN quantum well and the colloidal quantum dots decreased with increases in the driving voltage or the driving time. Under high driving voltages, the decreases in the quantum efficiency of the colloidal quantum dots and the energy transfer efficiency can be attributed to Auger recombination, while those decreases under long driving time are due to photo-bleaching and Auger recombination.

  17. Multicycle rapid thermal annealing optimization of Mg-implanted GaN: Evolution of surface, optical, and structural properties

    SciTech Connect

    Greenlee, Jordan D.; Feigelson, Boris N.; Anderson, Travis J.; Hite, Jennifer K.; Mastro, Michael A.; Eddy, Charles R.; Hobart, Karl D.; Kub, Francis J.; Tadjer, Marko J.

    2014-08-14

    The first step of a multi-cycle rapid thermal annealing process was systematically studied. The surface, structure, and optical properties of Mg implanted GaN thin films annealed at temperatures ranging from 900 to 1200?C were investigated by Raman spectroscopy, photoluminescence, UV-visible spectroscopy, atomic force microscopy, and Nomarski microscopy. The GaN thin films are capped with two layers of in-situ metal organic chemical vapor deposition -grown AlN and annealed in 24 bar of N{sub 2} overpressure to avoid GaN decomposition. The crystal quality of the GaN improves with increasing annealing temperature as confirmed by UV-visible spectroscopy and the full widths at half maximums of the E{sub 2} and A{sub 1} (LO) Raman modes. The crystal quality of films annealed above 1100?C exceeds the quality of the as-grown films. At 1200?C, Mg is optically activated, which is determined by photoluminescence measurements. However, at 1200?C, the GaN begins to decompose as evidenced by pit formation on the surface of the samples. Therefore, it was determined that the optimal temperature for the first step in a multi-cycle rapid thermal anneal process should be conducted at 1150?C due to crystal quality and surface morphology considerations.

  18. Utilization of native oxygen in Eu(RE)-doped GaN for enabling device compatibility in optoelectronic applications

    DOE PAGES [OSTI]

    Mitchell, Brandon; Timmerman, D.; Poplawsky, Jonathan D.; Zhu, W.; Lee, D.; Wakamatsu, R.; Takatsu, J.; Matsuda, M.; Guo, Wei; Lorenz, K.; et al

    2016-01-04

    The detrimental influence of oxygen on the performance and reliability of V/III nitride based devices is well known. However, the influence of oxygen on the nature of the incorporation of other co-dopants, such as rare earth ions, has been largely overlooked in GaN. Here, we report the first comprehensive study of the critical role that oxygen has on Eu in GaN, as well as atomic scale observation of diffusion and local concentration of both atoms in the crystal lattice. We find that oxygen plays an integral role in the location, stability, and local defect structure around the Eu ions thatmore » were doped into the GaN host. Although the availability of oxygen is essential for these properties, it renders the material incompatible with GaN-based devices. However, the utilization of the normally occurring oxygen in GaN is promoted through structural manipulation, reducing its concentration by 2 orders of magnitude, while maintaining both the material quality and the favorable optical properties of the Eu ions. Furthermore, these findings open the way for full integration of RE dopants for optoelectronic functionalities in the existing GaN platform.« less

  19. Status of wind energy in Germany

    SciTech Connect

    Gerdes, G.; Molly, J.P.; Rehfeldt, K.

    1996-12-31

    By the end of 1995 in total 3655 wind turbines (WT`s) were installed in Germany with a total capacity of 1,136 MW. In the year 1995 alone the WT installations grew by 1,070 units with 505 MW. About 40% of the 1995 installations were sold to inland states of Germany with their lower wind speed potential. This fast development occurred in parallel to continuously reduced local state and federal subsidies. The further development is based mainly on the guaranteed reimbursement due to the Electricity Feed Law. But since some time the electricity utilities fight back on all legal and political levels to get cancelled the unloved Electricity Feed Law and since two years the building construction law with the foreseen privilege for WT`s is discussed without any result. All these difficulties affect investors and credit giving banks in such a negative way, that the further annual increase in wind power installation for 1996 could be 10 to 20% less than in 1995. Many of the new commercial Megawatt WT`s have pitch control and variable rotor speed which cause better electrical power quality and lower life time loads. From statistical evaluations on technical data of WT`s a good overview of the further development is derived. 8 refs., 10 figs.

  20. Ab initio study on noncompensated CrO codoping of GaN for enhanced solar energy conversion

    SciTech Connect

    Pan, Hui; Gu, Baohua; Eres, Gyula; Zhang, Zhenyu

    2010-03-01

    We describe a novel photocatalyst obtained by codoping GaN with CrO, according to a new "noncompensated" codoping concept based on first-principles calculations. The approach enables controllable narrowing of the GaN band gap with significantly enhanced carrier mobility and photocatalytic activity in the visible light region and thus offers immense potential for application in solar energy conversion, water splitting, and a variety of solar-assisted photocatalysis. Our calculations indicate that the formation energy for the cation doping is greatly reduced by noncompensated codoping with an anion. Although Cr doping alone can split the band gap with the formation of an intermediate band, the mobility is low due to carrier trapping by the localized states. The first-principles calculations also demonstrate that CrO codoping of GaN shifts the Fermi level into the conduction band resulting in high carrier density and mobility.

  1. Dispersion and absorption of longitudinal electro-kinetic wave in ion-implanted GaN semiconductor plasmas

    SciTech Connect

    Soni, Dilip; Sharma, Giriraj; Saxena, Ajay; Jadhav, Akhilesh

    2015-07-31

    An analytical study on propagation characteristics of longitudinal electro-kinetic (LEK) waves is presented. Based on multi-fluid model of plasma, we have derived a dispersion relation for LEK waves in colloid laden GaN semiconductor plasmas. It is assumed that ions are implanted to form colloids in the GaN sample. The colloids are continuously bombarded by the plasma particles and stick on them, but they acquire a net negative charge due to relatively higher mobility of electrons. It is found from the dispersion relation that the presence of charged colloids not only modifies the existing modes but also supports new novel modes of LEKWs. It is hoped that the study would enhance understanding on dispersion and absorption of LEKWs and help in singling out the appropriate configurations in which GaN crystal would be better suited for fabrication of microwave devices.

  2. Properties of radio-frequency-sputter-deposited GaN films in a nitrogen/hydrogen mixed gas

    SciTech Connect

    Miyazaki, Takayuki; Takada, Kouhei; Adachi, Sadao; Ohtsuka, Kohji

    2005-05-01

    GaN films have been deposited by reactive sputtering in nitrogen gas at pressures from 0.08 to 2.70 Pa with and without the addition of hydrogen gas. X-ray diffraction (XRD), Fourier transform infrared (FTIR), optical absorption, and photoluminescence (PL) spectroscopy have been used to characterize the sputter-deposited GaN films. The XRD pattern reveals that the GaN films deposited in nitrogen gas at pressures lower than 0.53 Pa are polycrystals with the (0001) texture ({alpha}-GaN), while those deposited at or above 1.07 Pa display mixed crystalline orientations or an amorphous-like nature. The GaN:H films deposited in nitrogen/hydrogen mixed gas, on the other hand, show an amorphous or amorphous-like nature. The FTIR spectra indicate that the GaN:H films show peaks arising from hydrogen-related bonds at {approx}1000 and {approx}3200 cm{sup -1}, in addition to the GaN absorption band at {approx}555 cm{sup -1}. The optical absorption spectra at 300 K indicate the fundamental absorption edges at {approx}3.38 and {approx}3.7 eV for the highly oriented {alpha}-GaN and amorphous GaN:H films, respectively. PL emission has been observed from sputter-deposited {alpha}-GaN films at temperatures below 100 K. The GaN:H films also show strong band-edge and donor-acceptor pair emissions. The PL emission in the GaN:H film may arise from crystalline GaN particles embedded in the amorphous GaN matrix.

  3. Fundamental Bulk/Surface Structure Photoactivity Relationships of Supported (Rh2-yCryO3)/GaN Photocatalysts

    SciTech Connect

    Phivilay, Somphonh; Roberts, Charles; Puretzky, Alexander A; Domen, Kazunari Domen; Wachs, Israel

    2013-01-01

    ABSTRACT. The supported (Rh2-yCryO3)/GaN photocatalyst was examined as a model nitride photocatalyst system to assist in the development of fundamental structure photoactivity relationships for UV activated water splitting. Surface characterization of the outermost surface layers by High Sensitivity-LEIS and High Resolution-XPS revealed for the first time that the GaN support consists of a GaOx outermost surface layer and a thin film of GaOxNy in the surface region. HR-XPS also demonstrates that the supported (Rh2-yCryO3) mixed oxide nanoparticles (NPs) exclusively consist of Cr+3 and Rh+3 cations and are surface enriched for the supported (Rh2-yCryO3)/GaN photocatalyst. Bulk analysis by Raman and UV-vis spectroscopy show that the bulk molecular and electronic structures, respectively, of the GaN support are not perturbed by the deposition of the (Rh2-yCryO3) mixed oxide NPs. The function of the GaN bulk lattice is to generate photoexcited electrons/holes, with the electrons harnessed by the surface Rh+3 sites for evolution of H2 and the holes trapped at the Ga oxide/oxynitride surface sites for splitting of water and evolving O2. These new structure-photoactivity relationships for supported (Rh2-yCryO3)/GaN also extend to the best performing visible light activated supported (Rh2-yCryO3)/(Ga1-xZnx)(N1-xOx) photocatalyst.

  4. Electroreflectance study of the effect of {gamma} radiation on the optical properties of epitaxial GaN films

    SciTech Connect

    Belyaev, A. E.; Klyui, N. I. Konakova, R. V.; Lukyanov, A. N.; Danilchenko, B. A.; Sveshnikov, J. N.; Klyui, A. N.

    2012-03-15

    Experimental data on the electroreflectance spectra of {gamma}-irradiated epitaxial GaN films on sapphire are reported. The irradiation doses are 10{sup 5}-2 Multiplication-Sign 10{sup 6} rad. The theoretical electroreflectance spectra calculated on the basis of a model of three types of transitions are in agreement with experimental data with reasonable accuracy. The energies and broadenings of the transitions derived in the context of the model give grounds to infer that, in the GaN films, there are internal stresses dependent on the {gamma}-irradiation dose.

  5. Nanoscale size dependence parameters on lattice thermal conductivity of Wurtzite GaN nanowires

    SciTech Connect

    Mamand, S.M.; Omar, M.S.; Muhammad, A.J.

    2012-05-15

    Graphical abstract: Temperature dependence of calculated lattice thermal conductivity of Wurtzite GaN nanowires. Highlights: Black-Right-Pointing-Pointer A modified Callaway model is used to calculate lattice thermal conductivity of Wurtzite GaN nanowires. Black-Right-Pointing-Pointer A direct method is used to calculate phonon group velocity for these nanowires. Black-Right-Pointing-Pointer 3-Gruneisen parameter, surface roughness, and dislocations are successfully investigated. Black-Right-Pointing-Pointer Dislocation densities are decreases with the decrease of wires diameter. -- Abstract: A detailed calculation of lattice thermal conductivity of freestanding Wurtzite GaN nanowires with diameter ranging from 97 to 160 nm in the temperature range 2-300 K, was performed using a modified Callaway model. Both longitudinal and transverse modes are taken into account explicitly in the model. A method is used to calculate the Debye and phonon group velocities for different nanowire diameters from their related melting points. Effect of Gruneisen parameter, surface roughness, and dislocations as structure dependent parameters are successfully used to correlate the calculated values of lattice thermal conductivity to that of the experimentally measured curves. It was observed that Gruneisen parameter will decrease with decreasing nanowire diameters. Scattering of phonons is assumed to be by nanowire boundaries, imperfections, dislocations, electrons, and other phonons via both normal and Umklapp processes. Phonon confinement and size effects as well as the role of dislocation in limiting thermal conductivity are investigated. At high temperatures and for dislocation densities greater than 10{sup 14} m{sup -2} the lattice thermal conductivity would be limited by dislocation density, but for dislocation densities less than 10{sup 14} m{sup -2}, lattice thermal conductivity would be independent of that.

  6. Impact of the GaN nanowire polarity on energy harvesting

    SciTech Connect

    Gogneau, Noelle Galopin, Elisabeth; Guilet, Stephane; Travers, Laurent; Harmand, Jean-Christophe; Chrétien, Pascal; Houzé, Frédéric

    2014-05-26

    We investigate the piezoelectric generation properties of GaN nanowires (NWs) by atomic force microscopy equipped with a Resiscope module for electrical measurements. By correlating the topography profile of the NWs with the recorded voltage peaks generated by these nanostructures in response to their deformation, we demonstrate the influence of their polarity on the rectifying behavior of the Schottky diode formed between the NWs and the electrode of measurement. These results establish that the piezo-generation mechanism crucially depends on the structural characteristics of the NWs.

  7. Mechanism of the GaN LED efficiency falloff with increasing current

    SciTech Connect

    Bochkareva, N. I.; Voronenkov, V. V.; Gorbunov, R. I.; Zubrilov, A. S.; Lelikov, Y. S.; Latyshev, F. E.; Rebane, Y. T.; Tsyuk, A. I.; Shreter, Y. G.

    2010-06-15

    The quantum efficiency of GaN LED structures has been studied at various temperatures and biases. It was found that an efficiency falloff is observed with increasing current density and, simultaneously, the tunnel component of the current through the LED grows and the quasi-Fermi levels reach the mobility edge in the InGaN active layer. It is shown that the internal quantum efficiency falloff with increasing current density is due to the carrier leakage from the quantum well as a result of tunnel transitions from its band-tail states to local defect-related energy levels within the energy gaps of the barrier layers.

  8. Enhanced UV detection by non-polar epitaxial GaN films

    SciTech Connect

    Mukundan, Shruti; Chandan, Greeshma; Mohan, Lokesh; Krupanidhi, S. B.; Roul, Basanta; Shetty, Arjun

    2015-12-15

    Nonpolar a-GaN (11-20) epilayers were grown on r-plane (1-102) sapphire substrates using plasma assisted molecular beam epitaxy. High resolution x-ray diffractometer confirmed the orientation of the grown film. Effect of the Ga/N ratio on the morphology and strain of a-GaN epilayers was compared and the best condition was obtained for the nitrogen flow of 1 sccm. Atomic force microscopy was used to analyze the surface morphology while the strain in the film was quantitatively measured using Raman spectroscopy and qualitatively analyzed by reciprocal space mapping technique. UV photo response of a-GaN film was measured after fabricating a metal-semiconductor-metal structure over the film with gold metal. The external quantum efficiency of the photodetectors fabricated in the (0002) polar and (11-20) nonpolar growth directions were compared in terms of responsivity and nonpolar GaN showed the best sensitivity at the cost of comparatively slow response time.

  9. The effect of N-polar GaN domains as Ohmic contacts

    SciTech Connect

    Xie, J.; Mita, S.; Collazo, R.; Rice, A.; Tweedie, J.; Sitar, Z.

    2010-09-20

    Transfer line method measurements revealed that if the Ohmic contact regions were replaced by N-polar GaN, the contact resistance could be reduced from 0.71 {Omega} mm (or {rho}{sub c}=4x10{sup -6} {Omega} cm{sup 2}) to 0.24 {Omega} mm for a {approx}200 nm thick Si-doped GaN layer. The reduction in contact resistance was largely due to the {approx}10{sup 19} cm{sup -3} free carriers in N-polar source/drain regions as measured by Hall effect. Secondary ion mass spectroscopy confirmed that oxygen doping in the N-polar region was more than three orders of magnitude greater than that in the Ga-polar region that was explained by the large difference in the adsorption energy for oxygen ({approx}1.3 eV/atom) between the N- and Ga-polar surfaces during the metalorganic chemical vapor deposition.

  10. Excitation mechanisms of Er optical centers in GaN epilayers

    SciTech Connect

    George, D. K.; Hawkins, M. D.; McLaren, M.; Vinh, N. Q.; Jiang, H. X.; Lin, J. Y.; Zavada, J. M.

    2015-10-26

    We report direct evidence of two mechanisms responsible for the excitation of optically active Er{sup 3+} ions in GaN epilayers grown by metal-organic chemical vapor deposition. These mechanisms, resonant excitation via the higher-lying inner 4f shell transitions and band-to-band excitation of the semiconductor host, lead to narrow emission lines from isolated and the defect-related Er optical centers. However, these centers have different photoluminescence spectra, local defect environments, decay dynamics, and excitation cross sections. The photoluminescence at 1.54 μm from the isolated Er optical center which can be excited by either mechanism has the same decay dynamics, but possesses a much higher excitation cross-section under band-to-band excitation. In contrast, the photoluminescence at 1.54 μm from the defect-related Er optical center can only be observed through band-to-band excitation but has the largest excitation cross-section. These results explain the difficulty in achieving gain in Er doped GaN and indicate approaches for realization of optical amplification, and possibly lasing, at room temperature.

  11. Surfactant assisted growth of MgO films on GaN

    SciTech Connect

    Paisley, Elisibeth A.; Shelton, T C; Mita, S; Gaddy, Brian E.; Irving, D L; Christen, Hans M; Sitar, Z; Biegalski, Michael D; Maria, Jon Paul

    2012-01-01

    Thin epitaxial films of <111> oriented MgO on [0001]-oriented GaN were grown by molecular beam epitaxy (MBE) and pulsed laser deposition (PLD) using the assistance of a vapor phase surfactant. In both cases, surfactant incorporation enabled layer-by-layer growth and a smooth terminal surface due to stabilizing the {111} rocksalt facet. MBE growth of MgO in water terminates after several monolayers, and is attributed to saturation of surface active sites needed to facilitate the Mg oxidation reaction. MgO films prepared by PLD grow continuously, this occurs due to the presence of excited oxidizing species in the laser plasma eliminate the need for catalytic surface sites. Metal-insulator-semiconductor capacitor structures were fabricated on n-type GaN. A comparison of leakage current density for conventional and surfactant-assisted growth reveals a nearly two order of magnitude reduction in leakage current density for the smoother surfactant-assisted samples. Collectively, these data verify numerous predictions and calculations regarding the role of H-termination in regulating the habit of MgO crystals.

  12. Direct spontaneous growth and interfacial structural properties of inclined GaN nanopillars on r-plane sapphire

    SciTech Connect

    Adikimenakis, A.; Aretouli, K. E.; Tsagaraki, K.; Androulidaki, M.; Georgakilas, A.; Lotsari, A.; Dimitrakopulos, G. P. Kehagias, Th.; Komninou, Ph.

    2015-06-28

    The spontaneous growth of GaN nanopillars (NPs) by direct plasma-assisted molecular beam epitaxy on nitridated r-plane sapphire substrates has been studied. The emanation of metal-polarity NPs from inside an a-plane nonpolar GaN film was found to depend on both the substrate nitridation and the growth conditions. The density of NPs increased with increasing the duration of the nitridation process and the power applied on the radio-frequency plasma source, as well as the III/V flux ratio, while variation of the first two parameters enhanced the roughness of the substrate's surface. Transmission electron microscopy (TEM) techniques were employed to reveal the structural characteristics of the NPs and their nucleation mechanism from steps on the sapphire surface and/or interfacial semipolar GaN nanocrystals. Lattice strain measurements showed a possible Al enrichment of the first 5–6 monolayers of the NPs. By combining cross-sectional and plan-view TEM observations, the three-dimensional model of the NPs was constructed. The orientation relationship and interfacial accommodation between the NPs and the nonpolar a-plane GaN film were also elucidated. The NPs exhibited strong and narrow excitonic emission, suggesting an excellent structural quality.

  13. Growth modes of InN(000-1) on GaN buffer layers on sapphire

    SciTech Connect

    Liu, Bing; Kitajima, Takeshi; Chen, Dongxue; Leone, Stephen R.

    2005-01-24

    In this work, using atomic force microscopy and scanning tunneling microscopy, we study the surface morphologies of epitaxial InN films grown by plasma-assisted molecular beam epitaxy with intervening GaN buffer layers on sapphire substrates. On smooth GaN buffer layers, nucleation and evolution of three-dimensional InN islands at various coverages and growth temperatures are investigated. The shapes of the InN islands are observed to be predominantly mesa-like with large flat (000-1) tops, which suggests a possible role of indium as a surfactant. Rough GaN buffer layers composed of dense small GaN islands are found to significantly improve uniform InN wetting of the substrates, on which atomically smooth InN films are obtained that show the characteristics of step-flow growth. Scanning tunneling microscopy imaging reveals the defect-mediated surface morphology of smooth InN films, including surface terminations of screw dislocations and a high density of shallow surface pits with depths less than 0.3 nm. The mechanisms of the three-dimensional island size and shape evolution and formation of defects on smooth surfaces are considered.

  14. Impact of defects on the electrical transport, optical properties and failure mechanisms of GaN nanowires.

    SciTech Connect

    Armstrong, Andrew M.; Aubry, Sylvie; Shaner, Eric Arthur; Siegal, Michael P.; Li, Qiming; Jones, Reese E.; Westover, Tyler; Wang, George T.; Zhou, Xiao Wang; Talin, Albert Alec; Bogart, Katherine Huderle Andersen; Harris, C. Thomas; Huang, Jian Yu

    2010-09-01

    We present the results of a three year LDRD project that focused on understanding the impact of defects on the electrical, optical and thermal properties of GaN-based nanowires (NWs). We describe the development and application of a host of experimental techniques to quantify and understand the physics of defects and thermal transport in GaN NWs. We also present the development of analytical models and computational studies of thermal conductivity in GaN NWs. Finally, we present an atomistic model for GaN NW electrical breakdown supported with experimental evidence. GaN-based nanowires are attractive for applications requiring compact, high-current density devices such as ultraviolet laser arrays. Understanding GaN nanowire failure at high-current density is crucial to developing nanowire (NW) devices. Nanowire device failure is likely more complex than thin film due to the prominence of surface effects and enhanced interaction among point defects. Understanding the impact of surfaces and point defects on nanowire thermal and electrical transport is the first step toward rational control and mitigation of device failure mechanisms. However, investigating defects in GaN NWs is extremely challenging because conventional defect spectroscopy techniques are unsuitable for wide-bandgap nanostructures. To understand NW breakdown, the influence of pre-existing and emergent defects during high current stress on NW properties will be investigated. Acute sensitivity of NW thermal conductivity to point-defect density is expected due to the lack of threading dislocation (TD) gettering sites, and enhanced phonon-surface scattering further inhibits thermal transport. Excess defect creation during Joule heating could further degrade thermal conductivity, producing a viscous cycle culminating in catastrophic breakdown. To investigate these issues, a unique combination of electron microscopy, scanning luminescence and photoconductivity implemented at the nanoscale will be used in

  15. Tellurium n-type doping of highly mismatched amorphous GaN1-xAsx alloys in plasma-assisted molecular beam epitaxy

    DOE PAGES [OSTI]

    Novikov, S. V.; Ting, M.; Yu, K. M.; Sarney, W. L.; Martin, R. W.; Svensson, S. P.; Walukiewicz, W.; Foxon, C. T.

    2014-10-01

    In this paper we report our study on n-type Te doping of amorphous GaN1-xAsx layers grown by plasma-assisted molecular beam epitaxy. We have used a low temperature PbTe source as a source of tellurium. Reproducible and uniform tellurium incorporation in amorphous GaN1-xAsx layers has been successfully achieved with a maximum Te concentration of 9×10²⁰ cm⁻³. Tellurium incorporation resulted in n-doping of GaN1-xAsx layers with Hall carrier concentrations up to 3×10¹⁹ cm⁻³ and mobilities of ~1 cm²/V s. The optimal growth temperature window for efficient Te doping of the amorphous GaN1-xAsx layers has been determined.

  16. Effects of GaN interlayer on the transport properties of lattice-matched AlInN/AlN/GaN heterostructures

    SciTech Connect

    Wu, F.; Gao, K. H. Li, Z. Q.; Lin, T.; Zhou, W. Z.

    2015-04-21

    We study the effects of GaN interlayer on the transport properties of two-dimensional electron gases confined in lattice-matched AlInN/AlN/GaN heterostructures. It is found that the Hall mobility is evidently enhanced when an additional ultrathin GaN interlayer is introduced between AlInN and AlN layers. The enhancement of the Hall mobility is especially remarkable at low temperature. The high Hall mobility results in a low sheet resistance of 23 Ω/◻ at 2 K. Meanwhile, Shubnikov-de Haas oscillations (SdH) are also remarkably enhanced due to the existence of GaN interlayer. The enhancement of the SdH oscillations is related to the larger quantum mobility μ{sub q} owing to the suppression of the interface roughness, alloy disorder, and ionized impurity scatterings by the GaN interlayer.

  17. Highly c-axis oriented GaN films grown on free-standing diamond substrates for high-power devices

    SciTech Connect

    Zhang, D. [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China) [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Ministry of Education, Dalian University of Technology, Dalian 116024 (China); Bian, J.M., E-mail: jmbian@dlut.edu.cn [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Qin, F.W.; Wang, J.; Pan, L. [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China) [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Ministry of Education, Dalian University of Technology, Dalian 116024 (China); Zhao, J.M. [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)] [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Zhao, Y.; Bai, Y.Z. [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China) [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Ministry of Education, Dalian University of Technology, Dalian 116024 (China); Du, G.T. [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)] [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

    2011-10-15

    Highlights: {yields} GaN films are deposited on diamond substrates by ECR-PEMOCVD. {yields} Influence of deposition temperature on the properties of samples is investigated. {yields} Properties of GaN films are dependent on the deposition temperature. -- Abstract: GaN films with highly c-axis preferred orientation are deposited on free-standing thick diamond films by low temperature electron cyclotron resonance plasma enhanced metal organic chemical vapor deposition (ECR-PEMOCVD). The TMGa and N{sub 2} are applied as precursors of Ga and N, respectively. The quality of as-grown GaN films are systematically investigated as a function of deposition temperature by means of X-ray diffraction (XRD) analysis, Hall Effect measurement (HL), room temperature photoluminescence (PL) and atomic force microscopy (AFM). The results show that the dense and uniformed GaN films with highly c-axis preferred orientation are successfully achieved on free-standing diamond substrates under optimized deposition temperature of 400 {sup o}C, and the room temperature PL spectra of the optimized GaN film show a intense ultraviolet near band edge emission and a weak yellow luminescence. The obtained GaN/diamond structure has great potential for the development of high-power semiconductor devices due to its excellent heat dissipation nature.

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

    SciTech Connect

    Nandi, R. Mohan, S. Major, S. S.; Srinivasa, R. S.

    2014-04-24

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

  19. The possibly important role played by Ga{sub 2}O{sub 3} during the activation of GaN photocathode

    SciTech Connect

    Fu, Xiaoqian E-mail: 214808748@qq.com; Wang, Honggang; Zhang, Junju; Li, Zhiming; Cui, Shiyao; Zhang, Lejuan

    2015-08-14

    Three different chemical solutions are used to remove the possible contamination on GaN surface, while Ga{sub 2}O{sub 3} is still found at the surface. After thermal annealing at 710 °C in the ultrahigh vacuum (UHV) chamber and activated with Cs/O, all the GaN samples are successfully activated to the effective negative electron affinity (NEA) photocathodes. Among all samples, the GaN sample with the highest content of Ga{sub 2}O{sub 3} after chemical cleaning obtains the highest quantum efficiency. By analyzing the property of Ga{sub 2}O{sub 3}, the surface processing results, and electron affinity variations during Cs and Cs/O{sub 2} deposition on GaN of other groups, it is suggested that before the adsorption of Cs, Ga{sub 2}O{sub 3} is not completely removed from GaN surface in our samples, which will combine with Cs and lead to a large decrease in electron affinity. Furthermore, the effective NEA is formed for GaN photocathode, along with the surface downward band bending. Based on this assumption, a new dipole model Ga{sub 2}O{sub 3}-Cs is suggested, and the experimental effects are explained and discussed.

  20. Demonstration of forward inter-band tunneling in GaN by polarization engineering

    SciTech Connect

    Krishnamoorthy, Sriram; Park, Pil Sung; Rajan, Siddharth

    2011-12-05

    We report on the design, fabrication, and characterization of GaN interband tunnel junction showing forward tunneling characteristics. We have achieved very high forward tunneling currents (153 mA/cm{sup 2} at 10 mV, and 17.7 A/cm{sup 2} peak current) in polarization-engineered GaN/InGaN/GaN heterojunction diodes grown by plasma assisted molecular beam epitaxy. We also report the observation of repeatable negative differential resistance in interband III-Nitride tunnel junctions, with peak-valley current ratio of 4 at room temperature. The forward current density achieved in this work meets the typical current drive requirements of a multi-junction solar cell.

  1. Influence of the adatom diffusion on selective growth of GaN nanowire regular arrays

    SciTech Connect

    Gotschke, T.; Schumann, T.; Limbach, F.; Calarco, R.; Stoica, T.

    2011-03-07

    Molecular beam epitaxy (MBE) on patterned Si/AlN/Si(111) substrates was used to obtain regular arrays of uniform-size GaN nanowires (NWs). The silicon top layer has been patterned with e-beam lithography, resulting in uniform arrays of holes with different diameters (d{sub h}) and periods (P). While the NW length is almost insensitive to the array parameters, the diameter increases significantly with d{sub h} and P till it saturates at P values higher than 800 nm. A diffusion induced model was used to explain the experimental results with an effective diffusion length of the adatoms on the Si, estimated to be about 400 nm.

  2. Monolithic single GaN nanowire laser with photonic crystal microcavity on silicon

    SciTech Connect

    Heo, Junseok; Guo Wei; Bhattacharya, Pallab

    2011-01-10

    Optically pumped lasing at room temperature in a silicon based monolithic single GaN nanowire with a two-dimensional photonic crystal microcavity is demonstrated. Catalyst-free nanowires with low density ({approx}10{sup 8} cm{sup -2}) are grown on Si by plasma-assisted molecular beam epitaxy. High resolution transmission electron microscopy images reveal that the nanowires are of wurtzite structure and they have no observable defects. A single nanowire laser fabricated on Si is characterized by a lasing transition at {lambda}=371.3 nm with a linewidth of 0.55 nm. The threshold is observed at a pump power density of {approx}120 kW/cm{sup 2} and the spontaneous emission factor {beta} is estimated to be 0.08.

  3. Resonant energy transfer between Eu luminescent sites and their local geometry in GaN

    SciTech Connect

    Timmerman, Dolf; Wakamatsu, Ryuta; Tanaka, Kazuteru; Lee, Dong-gun; Koizumi, Atsushi; Fujiwara, Yasufumi

    2015-10-12

    Eu-doped GaN is a solid state material with promising features for quantum manipulation. In this study, we investigate the population dynamics of Eu in ions in this system by resonant excitation. From differences in the emission related to transitions between the {sup 5}D{sub 0} and {sup 7}F{sub 2} manifold in the Eu ions, we can distinguish different luminescence sites and observe that a resonant energy transfer takes place between two of these sites which are in proximity of each other. The time constants related to this energy transfer are on the order of 100 μs. By using different substrates, the energy transfer efficiency could be strongly altered, and it is demonstrated that the coupling between ions has an out-of-plane character. Based on these results, a microscopic model of this combined center is presented.

  4. Performance and breakdown characteristics of irradiated vertical power GaN P-i-N diodes

    SciTech Connect

    King, M. P.; Armstrong, A. M.; Dickerson, J. R.; Vizkelethy, G.; Fleming, R. M.; Campbell, J.; Wampler, W. R.; Kizilyalli, I. C.; Bour, D. P.; Aktas, O.; Nie, H.; Disney, D.; Wierer, Jr., J.; Allerman, A. A.; Moseley, M. W.; Kaplar, R. J.

    2015-10-29

    Electrical performance and defect characterization of vertical GaN P-i-N diodes before and after irradiation with 2.5 MeV protons and neutrons is investigated. Devices exhibit increase in specific on-resistance following irradiation with protons and neutrons, indicating displacement damage introduces defects into the p-GaN and n- drift regions of the device that impact on-state device performance. The breakdown voltage of these devices, initially above 1700 V, is observed to decrease only slightly for particle fluence <; 1013 cm-2. Furthermore, the unipolar figure of merit for power devices indicates that while the on-resistance and breakdown voltage degrade with irradiation, vertical GaN P-i-Ns remain superior to the performance of the best available, unirradiated silicon devices and on-par with unirradiated modern SiC-based power devices.

  5. Efficient Switches for Solar Power Conversion: Four Quadrant GaN Switch Enabled Three Phase Grid-Tied Microinverters

    SciTech Connect

    2012-02-13

    Solar ADEPT Project: Transphorm is developing power switches for new types of inverters that improve the efficiency and reliability of converting energy from solar panels into useable electricity for the grid. Transistors act as fast switches and control the electrical energy that flows in an electrical circuit. Turning a transistor off opens the circuit and stops the flow of electrical current; turning it on closes the circuit and allows electrical current to flow. In this way a transistor can be used to convert DC from a solar panel into AC for use in a home. Transphorm’s transistors will enable a single semiconductor device to switch electrical currents at high-voltage in both directions—making the inverter more compact and reliable. Transphorm is using Gallium Nitride (GaN) as a semiconductor material in its transistors instead of silicon, which is used in most conventional transistors, because GaN transistors have lower losses at higher voltages and switching frequencies.

  6. Method of growing GaN films with a low density of structural defects using an interlayer

    DOEpatents

    Bourret-Courchesne, Edith D.

    2003-01-01

    A dramatic reduction of the dislocation density in GaN was obtained by insertion of a single thin interlayer grown at an intermediate temperature (IT-IL) after the growth of an initial grown at high temperature. A description of the growth process is presented with characterization results aimed at understanding the mechanisms of reduction in dislocation density. A large percentage of the threading dislocations present in the first GaN epilayer are found to bend near the interlayer and do not propagate into the top layer which grows at higher temperature in a lateral growth mode. TEM studies show that the mechanisms of dislocation reduction are similar to those described for the epitaxial lateral overgrowth process, however a notable difference is the absence of coalescence boundaries.

  7. Propagation of electro-kinetic waves in magnetized GaN semiconductor with nano-sized ion colloids

    SciTech Connect

    Saxena, Ajay; Sharma, Giriraj; Jat, K. L.; Rishi, M. P.

    2015-07-31

    Based on hydrodynamic model of multi-component plasma, an analytical study on propagation of longitudinal electro-kinetic (LEK) waves in wurtzite and zincblende structures of GaN is carried out. Nano-sized ion colloids (NICs) are embedded in the sample by the technique of ion-implantation. The implanted NICs are considered massive by an order as compared to the host lattice points and do not participate in Based LEK perturbations. Though, the NICs are continuously bombarded by the electrons as well as the holes yet, the former acquires a net negative charge owing to relatively higher mobility of electrons and consequently results into depletion of electron density in the medium. It i s found that the presence of charged NICs significantly modifies the dispersion and amplification characteristics of LEK waves in magnetized GaN semiconductor plasma and their role becomes increasingly effective as the fraction of charge on them increases.

  8. The E2/M1 mixing ratio in the excitation of the {Delta} from polarized photo-reactions

    SciTech Connect

    The LEGS Collaboration

    1993-12-01

    In constituent quark models, a tensor interaction, mixing quark spins with their relative motion, is introduced to reproduce the observed baryon spectrum. This has a consequence completely analogous to the nuclear tensor force between the n and p in deuterium. A D state component is mixed into what would otherwise be a purely S-wave object. The D-wave component breaks spherical symmetry, resulting in a non-vanishing matrix element for the nucleon and a static quadrupole moment and deformation for its first excited state, the {Delta} resonance, at {approximately}325 MeV. The magnitude and sign of this D-state component are quite sensitive to the internal structure of the proton and have been of great interest in recent years. The intrinsic deformation of the spin 1/2 nucleon cannot be observed directly; it must be inferred from transition amplitudes such as N {yields} {Delta}. In a spherical bag model, the {Delta} is viewed as a pure quark-spin-flip transition proceeding only through M1 excitation. If there are D-state admixtures in the ground state of the nucleon and/or {Delta}, quadrupole excitation, in addition to spin-flip M1, is also allowed. The problem is to evaluate the relative magnitude of this E2 excitation in the presence of the dominant M1 transition. A variety of models predict this mixing ratio to be quite small, anywhere from {minus}0.9% to {minus}6%, so that a high degree of precision is demanded of experiment.

  9. Elimination of surface band bending on N-polar InN with thin GaN capping

    SciTech Connect

    Kuzmík, J. Haščík, Š.; Kučera, M.; Kúdela, R.; Dobročka, E.; Adikimenakis, A.; Mičušík, M.; Gregor, M.; Plecenik, A.; Georgakilas, A.

    2015-11-09

    0.5–1 μm thick InN (0001) films grown by molecular-beam epitaxy with N- or In-polarity are investigated for the presence of native oxide, surface energy band bending, and effects introduced by 2 to 4 monolayers of GaN capping. Ex situ angle-resolved x-ray photo-electron spectroscopy is used to construct near-surface (GaN)/InN energy profiles, which is combined with deconvolution of In3d signal to trace the presence of InN native oxide for different types of polarity and capping. Downwards surface energy band bending was observed on bare samples with native oxide, regardless of the polarity. It was found that the In-polar InN surface is most readily oxidized, however, with only slightly less band bending if compared with the N-polar sample. On the other hand, InN surface oxidation was effectively mitigated by GaN capping. Still, as confirmed by ultra-violet photo-electron spectroscopy and by energy band diagram calculations, thin GaN cap layer may provide negative piezoelectric polarization charge at the GaN/InN hetero-interface of the N-polar sample, in addition to the passivation effect. These effects raised the band diagram up by about 0.65 eV, reaching a flat-band profile.

  10. GaN nanowires with pentagon shape cross-section by ammonia-source molecular beam epitaxy

    DOE PAGES [OSTI]

    Lin, Yong; Leung, Benjamin; Li, Qiming; Figiel, Jeffrey J.; Wang, George T.

    2015-07-14

    In this study, ammonia-based molecular beam epitaxy (NH3-MBE) was used to grow catalyst-assisted GaN nanowires on (11¯02) r-plane sapphire substrates. Dislocation free [112¯0] oriented nanowires are formed with pentagon shape cross-section, instead of the usual triangular shape facet configuration. Specifically, the cross-section is the result of the additional two nonpolar {101¯0} side facets, which appear due to a decrease in relative growth rate of the {101¯0} facets to the {101¯1} and {101¯1} facets under the growth regime in NH3-MBE. Compared to GaN nanowires grown by Ni-catalyzed metal–organic chemical vapor deposition, the NH3-MBE grown GaN nanowires show more than an ordermore » of magnitude increase in band-edge to yellow luminescence intensity ratio, as measured by cathodoluminescence, indicating improved microstructural and optical properties.« less

  11. Transistors for Electric Motor Drives: High-Performance GaN HEMT Modules for Agile Power Electronics

    SciTech Connect

    2010-09-01

    ADEPT Project: Transphorm is developing transistors with gallium nitride (GaN) semiconductors that could be used to make cost-effective, high-performance power converters for a variety of applications, including electric motor drives which transmit power to a motor. A transistor acts like a switch, controlling the electrical energy that flows around an electrical circuit. Most transistors today use low-cost silicon semiconductors to conduct electrical energy, but silicon transistors don’t operate efficiently at high speeds and voltage levels. Transphorm is using GaN as a semiconductor material in its transistors because GaN performs better at higher voltages and frequencies, and it is more energy efficient than straight silicon. However, Transphorm is using inexpensive silicon as a base to help keep costs low. The company is also packaging its transistors with other electrical components that can operate quickly and efficiently at high power levels—increasing the overall efficiency of both the transistor and the entire motor drive.

  12. GaN nanowires with pentagon shape cross-section by ammonia-source molecular beam epitaxy

    SciTech Connect

    Lin, Yong; Leung, Benjamin; Li, Qiming; Figiel, Jeffrey J.; Wang, George T.

    2015-07-14

    In this study, ammonia-based molecular beam epitaxy (NH3-MBE) was used to grow catalyst-assisted GaN nanowires on (11¯02) r-plane sapphire substrates. Dislocation free [112¯0] oriented nanowires are formed with pentagon shape cross-section, instead of the usual triangular shape facet configuration. Specifically, the cross-section is the result of the additional two nonpolar {101¯0} side facets, which appear due to a decrease in relative growth rate of the {101¯0} facets to the {101¯1} and {101¯1} facets under the growth regime in NH3-MBE. Compared to GaN nanowires grown by Ni-catalyzed metal–organic chemical vapor deposition, the NH3-MBE grown GaN nanowires show more than an order of magnitude increase in band-edge to yellow luminescence intensity ratio, as measured by cathodoluminescence, indicating improved microstructural and optical properties.

  13. Electronic and optical device applications of hollow cathode plasma assisted atomic layer deposition based GaN thin films

    SciTech Connect

    Bolat, Sami Tekcan, Burak; Ozgit-Akgun, Cagla; Biyikli, Necmi; Okyay, Ali Kemal

    2015-01-15

    Electronic and optoelectronic devices, namely, thin film transistors (TFTs) and metalsemiconductormetal (MSM) photodetectors, based on GaN films grown by hollow cathode plasma-assisted atomic layer deposition (PA-ALD) are demonstrated. Resistivity of GaN thin films and metal-GaN contact resistance are investigated as a function of annealing temperature. Effect of the plasma gas and postmetallization annealing on the performances of the TFTs as well as the effect of the annealing on the performance of MSM photodetectors are studied. Dark current to voltage and responsivity behavior of MSM devices are investigated as well. TFTs with the N{sub 2}/H{sub 2} PA-ALD based GaN channels are observed to have improved stability and transfer characteristics with respect to NH{sub 3} PA-ALD based transistors. Dark current of the MSM photodetectors is suppressed strongly after high-temperature annealing in N{sub 2}:H{sub 2} ambient.

  14. Innovative energy technologies and climate policy in Germany

    SciTech Connect

    Schumacher, Katja; Sands, Ronald D.

    2006-12-01

    Due to the size and structure of its economy, Germany is one of the largest carbon emitters in the European Union. However, Germany is facing a major renewal and restructuring process in electricity generation. Within the next two decades, up to 50% of current electricity generation capacity may retire because of end-of-plant lifetime and the nuclear phase-out pact of 1998. Substantial opportunities therefore exist for deployment of advanced electricity generating technologies in both a projected baseline and in alternative carbon policy scenarios. We simulate the potential role of coal integrated gasification combined cycle (IGCC), natural gas combined cycle (NGCC), carbon dioxide capture and storage (CCS), and wind power within a computable general equilibrium of Germany from the present through 2050. These advanced technologies and their role within a future German electricity system are the focus of this paper. We model the response of greenhouse gas emissions in Germany to various technology and carbon policy assumptions over the next few decades. In our baseline scenario, all of the advanced technologies except CCS provide substantial contributions to electricity generation. We also calculate the carbon price where each fossil technology, combined with CCS, becomes competitive. Constant carbon price experiments are used to characterize the model response to a carbon policy. This provides an estimate of the cost of meeting an emissions target, and the share of emissions reductions available from the electricity generation sector.

  15. The biomethanation of waste material; An example in Germany

    SciTech Connect

    Shin, K.C. )

    1991-01-01

    This paper reports that digester gas (biogas) can be generated from anaerobic decomposition of organic waste substances. In the municipal sewage treatment plants in Germany most of the gas production is used for heating and electric power generation. The major portion of solid waste shall be returned to the economical circuit as biogas, compost and recyclable materials.

  16. Recycling process for recovery of gallium from GaN an e-waste of LED industry through ball milling, annealing and leaching

    SciTech Connect

    Swain, Basudev Mishra, Chinmayee; Kang, Leeseung; Park, Kyung-Soo Lee, Chan Gi; Hong, Hyun Seon

    2015-04-15

    Waste dust generated during manufacturing of LED contains significant amounts of gallium and indium, needs suitable treatment and can be an important resource for recovery. The LED industry waste dust contains primarily gallium as GaN. Leaching followed by purification technology is the green and clean technology. To develop treatment and recycling technology of these GaN bearing e-waste, leaching is the primary stage. In our current investigation possible process for treatment and quantitative leaching of gallium and indium from the GaN bearing e-waste or waste of LED industry dust has been developed. To recycle the waste and quantitative leaching of gallium, two different process flow sheets have been proposed. In one, process first the GaN of the waste the LED industry dust was leached at the optimum condition. Subsequently, the leach residue was mixed with Na{sub 2}CO{sub 3}, ball milled followed by annealing, again leached to recover gallium. In the second process, the waste LED industry dust was mixed with Na{sub 2}CO{sub 3}, after ball milling and annealing, followed acidic leaching. Without pretreatment, the gallium leaching was only 4.91 w/w % using 4 M HCl, 100 °C and pulp density of 20 g/L. After mechano-chemical processing, both these processes achieved 73.68 w/w % of gallium leaching at their optimum condition. The developed process can treat and recycle any e-waste containing GaN through ball milling, annealing and leaching. - Highlights: • Simplest process for treatment of GaN an LED industry waste developed. • The process developed recovers gallium from waste LED waste dust. • Thermal analysis and phase properties of GaN to Ga{sub 2}O{sub 3} and GaN to NaGaO{sub 2} revealed. • Solid-state chemistry involved in this process reported. • Quantitative leaching of the GaN was achieved.

  17. Why Are Resiential PV Prices in Germany So Much Lower Than in...

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Why Are Resiential PV Prices in Germany So Much Lower Than in the United States? Why Are Resiential PV Prices in Germany So Much Lower Than in the United States? The U.S. ...

  18. Characterization of GaN nanowires grown on PSi, PZnO and PGaN on Si (111) substrates by thermal evaporation

    SciTech Connect

    Shekari, Leila; Hassan, Haslan Abu; Thahab, Sabah M.; Hassan, Zainuriah

    2012-06-20

    In this research, we used an easy and inexpensive method to synthesize highly crystalline GaN nanowires (NWs); on different substrates such as porous silicon (PSi), porous zinc oxide (PZnO) and porous gallium nitride (PGaN) on Si (111) wafer by thermal evaporation using commercial GaN powder without any catalyst. Micro structural studies by scanning electron microscopy and transmission electron microscope measurements reveal the role of different substrates in the morphology, nucleation and alignment of the GaN nanowires. The degree of alignment of the synthesized nanowires does not depend on the lattice mismatch between wires and their substrates. Further structural and optical characterizations were performed using high resolution X-ray diffraction and energy-dispersive X-ray spectroscopy. Results indicate that the nanowires are of single-crystal hexagonal GaN. The quality and density of grown GaN nanowires for different substrates are highly dependent on the lattice mismatch between the nanowires and their substrates and also on the size of the porosity of the substrates. Nanowires grown on PGaN have the best quality and highest density as compared to nanowires on other substrates. By using three kinds of porous substrates, we are able to study the increase in the alignment and density of the nanowires.

  19. Carrier and photon dynamics in a topological insulator Bi{sub 2}Te{sub 3}/GaN type II staggered heterostructure

    SciTech Connect

    Chaturvedi, P.; Chouksey, S.; Banerjee, D.; Ganguly, S.; Saha, D.

    2015-11-09

    We have demonstrated a type-II band-aligned heterostructure between pulsed laser deposited topological insulator bismuth telluride and metal organic-chemical-vapour deposited GaN on a sapphire substrate. The heterostructure shows a large valence band-offset of 3.27 eV as determined from x-ray photoelectron spectroscopy, which is close to the bandgap of GaN (3.4 eV). Further investigation using x-ray diffraction, Raman spectroscopy, and energy-dispersive x-ray spectrum reveals the stoichiometric and material properties of bismuth telluride on GaN. Steady state photon emission from GaN is found to be modulated by the charge transfer process due to diffusion across the junction. The time constant involved with the charge transfer process is found to be 0.6 ns by transient absorption spectroscopy. The heterostructure can be used for designing devices with different functionalities and improving the performance of the existing devices on GaN.

  20. Thermoelectric Activities of European Community within Framework Programme 7 and additional activities in Germany

    Office of Energy Efficiency and Renewable Energy (EERE)

    Provides survey of basic and applied thermoelectric activities in Germany within the European Community Programme and in Fraunhofer IPM

  1. Radiation-induced defects in GaN bulk grown by halide vapor phase epitaxy

    SciTech Connect

    Duc, Tran Thien; Pozina, Galia; Son, Nguyen Tien; Janzén, Erik; Hemmingsson, Carl; Ohshima, Takeshi

    2014-09-08

    Defects induced by electron irradiation in thick free-standing GaN layers grown by halide vapor phase epitaxy were studied by deep level transient spectroscopy. In as-grown materials, six electron traps, labeled D2 (E{sub C}–0.24 eV), D3 (E{sub C}–0.60 eV), D4 (E{sub C}–0.69 eV), D5 (E{sub C}–0.96 eV), D7 (E{sub C}–1.19 eV), and D8, were observed. After 2 MeV electron irradiation at a fluence of 1 × 10{sup 14 }cm{sup −2}, three deep electron traps, labeled D1 (E{sub C}–0.12 eV), D5I (E{sub C}–0.89 eV), and D6 (E{sub C}–1.14 eV), were detected. The trap D1 has previously been reported and considered as being related to the nitrogen vacancy. From the annealing behavior and a high introduction rate, the D5I and D6 centers are suggested to be related to primary intrinsic defects.

  2. Electrochemical removal of hydrogen atoms in Mg-doped GaN epitaxial layers

    SciTech Connect

    Lee, June Key E-mail: hskim7@jbnu.ac.kr; Hyeon, Gil Yong; Tawfik, Wael Z.; Choi, Hee Seok; Ryu, Sang-Wan; Jeong, Tak; Jung, Eunjin; Kim, Hyunsoo E-mail: hskim7@jbnu.ac.kr

    2015-05-14

    Hydrogen atoms inside of an Mg-doped GaN epitaxial layer were effectively removed by the electrochemical potentiostatic activation (EPA) method. The role of hydrogen was investigated in terms of the device performance of light-emitting diodes (LEDs). The effect of the main process parameters for EPA such as solution type, voltage, and time was studied and optimized for application to LED fabrication. In optimized conditions, the light output of 385-nm LEDs was improved by about 26% at 30 mA, which was caused by the reduction of the hydrogen concentration by ∼35%. Further removal of hydrogen seems to be involved in the breaking of Ga-H bonds that passivate the nitrogen vacancies. An EPA process with high voltage breaks not only Mg-H bonds that generate hole carriers but also Ga-H bonds that generate electron carriers, thus causing compensation that impedes the practical increase of hole concentration, regardless of the drastic removal of hydrogen atoms. A decrease in hydrogen concentration affects the current-voltage characteristics, reducing the reverse current by about one order and altering the forward current behavior in the low voltage region.

  3. Yellow luminescence and related deep states in undoped GaN

    SciTech Connect

    Calleja, E.; Sanchez, F.J.; Basak, D.; Sanchez-Garcia, M.A.; Munoz, E.; Izpura, I.; Calle, F.; Tijero, J.M.; Sanchez-Rojas, J.L.; Beaumont, B.; Lorenzini, P.; Gibart, P.

    1997-02-01

    Photocapacitance spectra in undoped, metal-organic vapor-phase-epitaxy-grown GaN layers, in a range of photon energies from 0.6 to 3.5 eV, reveal two main persistent features: a broad increase of the capacitance from 2.0 to 2.5 eV, and a steep {ital decrease} at 1 eV, only observed after a previous light exposure to photon energies above 2.5 eV. A deep trap (E{sub v}+1 eV) that captures photoelectrons from the valence band, after being emptied with photons above 2.5 eV, is proposed as the origin of these features. Optical-current deep-level transient spectroscopy results also show the presence of a trap at 0.94 eV {ital above} the valence band, {ital only} detected after light excitation with photon energies above 2.5 eV. A correlation is found between the {open_quotes}yellow band{close_quotes} luminescence intensity at 2.2 eV and the amplitude of the photocapacitance decrease at 1 eV, pointing to a deep trap at 1 eV {ital above} the valence band as the recombination path for the yellow band. The detection of the yellow band with below-the-gap photoluminescence excitation supports the proposed model. {copyright} {ital 1997} {ital The American Physical Society}

  4. TEM studies of laterally overgrown GaN layers grown on non-polarsubstrates

    SciTech Connect

    Liliental-Weber, Z.; Ni, X.; Morkoc, H.

    2006-01-05

    Transmission electron microscopy (TEM) was used to study pendeo-epitaxial GaN layers grown on polar and non-polar 4H SiC substrates. The structural quality of the overgrown layers was evaluated using a number of TEM methods. Growth of pendeo-epitaxial layers on polar substrates leads to better structural quality of the overgrown areas, however edge-on dislocations are found at the meeting fronts of two wings. Some misorientation between the 'seed' area and wing area was detected by Convergent Beam Electron Diffraction. Growth of pendeo-epitaxial layers on non-polar substrates is more difficult. Two wings on the opposite site of the seed area grow in two different polar directions with different growth rates. Most dislocations in a wing grown with Ga polarity are 10 times wider than wings grown with N-polarity making coalescence of these layers difficult. Most dislocations in a wing grown with Ga polarity bend in a direction parallel to the substrate, but some of them also propagate to the sample surface. Stacking faults formed on the c-plane and prismatic plane occasionally were found. Some misorientation between the wings and seed was detected using Large Angle Convergent Beam Diffraction.

  5. Enhanced stability of Eu in GaN nanoparticles: Effects of Si co-doping

    SciTech Connect

    Kaur, Prabhsharan; Sekhon, S. S.; Zavada, J. M.; Kumar, Vijay

    2015-06-14

    Ab initio calculations on Eu doped (GaN){sub n} (n = 12, 13, and 32) nanoparticles show that Eu doping in nanoparticles is favorable compared with bulk GaN as a large fraction of atoms lie on the surface where strain can be released compared with bulk where often Eu doping is associated with a N vacancy. Co-doping of Si further facilitates Eu doping as strain from an oversized Eu atom and an undersized Si atom is compensated. These results along with low symmetry sites in nanoparticles make them attractive for developing strongly luminescent nanomaterials. The atomic and electronic structures are discussed using generalized gradient approximation (GGA) for the exchange-correlation energy as well as GGA + U formalism. In all cases of Eu (Eu + Si) doping, the magnetic moments are localized on the Eu site with a large value of 6μ{sub B} (7μ{sub B}). Our results suggest that co-doping can be a very useful way to achieve rare-earth doping in different hosts for optoelectronic materials.

  6. High-power blue laser diodes with indium tin oxide cladding on semipolar (202{sup }1{sup }) GaN substrates

    SciTech Connect

    Pourhashemi, A. Farrell, R. M.; Cohen, D. A.; Speck, J. S.; DenBaars, S. P.; Nakamura, S.

    2015-03-16

    We demonstrate a high power blue laser diode (LD) using indium tin oxide as a cladding layer on semipolar oriented GaN. These devices show peak output powers and external quantum efficiencies comparable to state-of-the-art commercial c-plane devices. Ridge waveguide LDs were fabricated on (202{sup }1{sup }) oriented GaN substrates using InGaN waveguiding layers and GaN cladding layers. At a lasing wavelength of 451?nm at room temperature, an output power of 2.52?W and an external quantum efficiency of 39% were measured from a single facet under a pulsed injection current of 2.34?A. The measured differential quantum efficiency was 50%.

  7. Performance enhancement of GaN metalsemiconductormetal ultraviolet photodetectors by insertion of ultrathin interfacial HfO{sub 2} layer

    SciTech Connect

    Kumar, Manoj E-mail: aokyay@ee.bilkent.edu.tr; Tekcan, Burak; Okyay, Ali Kemal E-mail: aokyay@ee.bilkent.edu.tr

    2015-03-15

    The authors demonstrate improved device performance of GaN metalsemiconductormetal ultraviolet (UV) photodetectors (PDs) by ultrathin HfO{sub 2} (UT-HfO{sub 2}) layer on GaN. The UT-HfO{sub 2} interfacial layer is grown by atomic layer deposition. The dark current of the PDs with UT-HfO{sub 2} is significantly reduced by more than two orders of magnitude compared to those without HfO{sub 2} insertion. The photoresponsivity at 360?nm is as high as 1.42 A/W biased at 5 V. An excellent improvement in the performance of the devices is ascribed to allowed electron injection through UT-HfO{sub 2} on GaN interface under UV illumination, resulting in the photocurrent gain with fast response time.

  8. Highly mismatched crystalline and amorphous GaN(1-x)As(x) alloys in the whole composition range

    SciTech Connect

    Yu, K. M.; Novikov, S. V.; Broesler, R.; Demchenko, I. N.; Denlinger, J. D.; Liliental-Weber, Z.; Luckert, F.; Martin, R. W.; Walukiewicz, W.; Foxon, C. T.

    2009-08-29

    Alloying is a commonly accepted method to tailor properties of semiconductor materials for specific applications. Only a limited number of semiconductor alloys can be easily synthesized in the full composition range. Such alloys are, in general, formed of component elements that are well matched in terms of ionicity, atom size, and electronegativity. In contrast there is a broad class of potential semiconductor alloys formed of component materials with distinctly different properties. In most instances these mismatched alloys are immiscible under standard growth conditions. Here we report on the properties of GaN1-xAsx, a highly mismatched, immiscible alloy system that was successfully synthesized in the whole composition range using a nonequilibrium low temperature molecular beam epitaxy technique. The alloys are amorphous in the composition range of 0.17GaN to ~;;0.8 eV at x~;;0.85. The reduction in the band gap can be attributed primarily to the downward movement of the conduction band for alloys with x>0.2, and to the upward movement of the valence band for alloys with x<0.2. The unique features of the band structure offer an opportunity of using GaN1-xAsx alloys for various types of solar power conversion devices.

  9. Better Catalysts through Microscopy: Nanometer Scale M1/M2 Intergrown Heterostructure in Mo-V-M Complex Oxides

    DOE PAGES [OSTI]

    He, Qian; Woo, Jungwon; Belianinov, Alex; Guliants, Vadim V.; Borisevich, Albina Y

    2015-01-01

    In recent decades, catalysis research has transformed from the predominantly empirical field to one where it is possible to control the catalytic properties via characterization and modification of the atomic-scale active centers. Many phenomena in catalysis, such as synergistic effect, however, transcend the atomic scale and also require the knowledge and control of the mesoscale structure of the specimen to harness. In this paper, we use our discovery of atomic-scale epitaxial interfaces in molybdenum vanadium based complex oxide catalysts systems (i.e., MoVMO, M = Ta, Te, Sb, Nb, etc.) to achieve control of the mesoscale structure of this complex mixturemore » of very different active phases. We can now achieve true epitaxial intergrowth between the catalytically critical M1 and M2 phases in the system that are hypothesized to have synergistic interactions, and demonstrate that the resulting catalyst has improved selectivity in the initial studies. Finally, we highlight the crucial role atomic scale characterization and mesoscale structure control play in uncovering the complex underpinnings of the synergistic effect in catalysis.« less

  10. Better Catalysts through Microscopy: Nanometer Scale M1/M2 Intergrown Heterostructure in Mo-V-M Complex Oxides

    SciTech Connect

    He, Qian [ORNL; Woo, Jungwon [University of Cincinnati; Belianinov, Alex [ORNL; Guliants, Vadim V. [University of Cincinnati; Borisevich, Albina Y [ORNL

    2015-01-01

    In recent decades, catalysis research has transformed from the predominantly empirical field to one where it is possible to control the catalytic properties via characterization and modification of the atomic-scale active centers. Many phenomena in catalysis, such as synergistic effect, however, transcend the atomic scale and also require the knowledge and control of the mesoscale structure of the specimen to harness. In this paper, we use our discovery of atomic-scale epitaxial interfaces in molybdenum vanadium based complex oxide catalysts systems (i.e., MoVMO, M = Ta, Te, Sb, Nb, etc.) to achieve control of the mesoscale structure of this complex mixture of very different active phases. We can now achieve true epitaxial intergrowth between the catalytically critical M1 and M2 phases in the system that are hypothesized to have synergistic interactions, and demonstrate that the resulting catalyst has improved selectivity in the initial studies. Finally, we highlight the crucial role atomic scale characterization and mesoscale structure control play in uncovering the complex underpinnings of the synergistic effect in catalysis.

  11. Results from power quality measurements in Germany - An overview

    SciTech Connect

    Gerdes, G.J.; Santjer, F.

    1996-12-31

    Grid interferences caused by wind turbines (WT) are getting a severe problem in Germany with the fast increasing number of installed turbines. The wind energy capacity was doubled annually in the past three years. The actual situation and the plannings for the next years will lead to a situation, where high wind energy penetration will exercise a big influence on the power and voltage quality of local utility networks. Measurements performed in Germany according to a national guideline show a big variety in power quality performance of WT`s, which does affect the requirements for grid connection and thus the economical situation of wind energy projects to a large extent. The results from more than 25 power quality measurements will be discussed in this paper. 5 refs., 5 figs., 1 tab.

  12. Ultraviolet light-emitting diodes grown by plasma-assisted molecular beam epitaxy on semipolar GaN (2021) substrates

    SciTech Connect

    Sawicka, M.; Grzanka, S.; Skierbiszewski, C.; Turski, H.; Muziol, G.; Krysko, M.; Grzanka, E.; Sochacki, T.; Siekacz, M.; Kucharski, R.

    2013-03-18

    Multi-quantum well (MQW) structures and light emitting diodes (LEDs) were grown on semipolar (2021) and polar (0001) GaN substrates by plasma-assisted molecular beam epitaxy. The In incorporation efficiency was found to be significantly lower for the semipolar plane as compared to the polar one. The semipolar MQWs exhibit a smooth surface morphology, abrupt interfaces, and a high photoluminescence intensity. The electroluminescence of semipolar (2021) and polar (0001) LEDs fabricated in the same growth run peaks at 387 and 462 nm, respectively. Semipolar LEDs with additional (Al,Ga)N cladding layers exhibit a higher optical output power but simultaneously a higher turn-on voltage.

  13. X-ray absorption and reflection as probes of the GaN conduction bands: Theory and experiments

    SciTech Connect

    Lambrecht, W.R.L.; Rashkeev, S.N.; Segall, B.

    1997-04-01

    X-ray absorption measurements are a well-known probe of the unoccupied states in a material. The same information can be obtained by using glancing angle X-ray reflectivity. In spite of several existing band structure calculations of the group III nitrides and previous optical studies in UV range, a direct probe of their conduction band densities of states is of interest. The authors performed a joint experimental and theoretical investigation using both of these experimental techniques for wurtzite GaN.

  14. Diagonalization of transfer matrix of supersymmetry U{sub q}(sl-caret(M+1|N+1)) chain with a boundary

    SciTech Connect

    Kojima, Takeo

    2013-04-15

    We study the supersymmetry U{sub q}(sl-caret(M+1|N+1)) analogue of the supersymmetric t-J model with a boundary. Our approach is based on the algebraic analysis method of solvable lattice models. We diagonalize the commuting transfer matrix by using the bosonizations of the vertex operators associated with the quantum affine supersymmetry U{sub q}(sl-caret(M+1|N+1)).

  15. Strong geometrical effects in submillimeter selective area growth and light extraction of GaN light emitting diodes on sapphire

    DOE PAGES [OSTI]

    Tanaka, Atsunori; Chen, Renjie; Jungjohann, Katherine L.; Dayeh, Shadi A.

    2015-11-27

    Advanced semiconductor devices often utilize structural and geometrical effects to tailor their characteristics and improve their performance. Our detailed understanding of such geometrical effects in the epitaxial selective area growth of GaN on sapphire substrates is reported here, and we utilize them to enhance light extraction from GaN light emitting diodes. Systematic size and spacing effects were performed side-by-side on a single 2” sapphire substrate to minimize experimental sampling errors for a set of 144 pattern arrays with circular mask opening windows in SiO2. We show that the mask opening diameter leads to as much as 4 times increase inmore » the thickness of the grown layers for 20 μm spacings and that spacing effects can lead to as much as 3 times increase in thickness for a 350 μm dot diameter. We also observed that the facet evolution in comparison with extracted Ga adatom diffusion lengths directly influences the vertical and lateral overgrowth rates and can be controlled with pattern geometry. Lastly, such control over the facet development led to 2.5 times stronger electroluminescence characteristics from well-faceted GaN/InGaN multiple quantum well LEDs compared to non-faceted structures.« less

  16. Strong geometrical effects in submillimeter selective area growth and light extraction of GaN light emitting diodes on sapphire

    SciTech Connect

    Tanaka, Atsunori; Chen, Renjie; Jungjohann, Katherine L.; Dayeh, Shadi A.

    2015-11-27

    Advanced semiconductor devices often utilize structural and geometrical effects to tailor their characteristics and improve their performance. Our detailed understanding of such geometrical effects in the epitaxial selective area growth of GaN on sapphire substrates is reported here, and we utilize them to enhance light extraction from GaN light emitting diodes. Systematic size and spacing effects were performed side-by-side on a single 2” sapphire substrate to minimize experimental sampling errors for a set of 144 pattern arrays with circular mask opening windows in SiO2. We show that the mask opening diameter leads to as much as 4 times increase in the thickness of the grown layers for 20 μm spacings and that spacing effects can lead to as much as 3 times increase in thickness for a 350 μm dot diameter. We also observed that the facet evolution in comparison with extracted Ga adatom diffusion lengths directly influences the vertical and lateral overgrowth rates and can be controlled with pattern geometry. Lastly, such control over the facet development led to 2.5 times stronger electroluminescence characteristics from well-faceted GaN/InGaN multiple quantum well LEDs compared to non-faceted structures.

  17. Ar{sup +}-irradiation-induced damage in hydride vapor-phase epitaxy GaN films

    SciTech Connect

    Nakano, Yoshitaka Ogawa, Daisuke; Nakamura, Keiji; Kawakami, Retsuo; Niibe, Masahito

    2015-07-15

    The authors have investigated the electrical characteristics of hydride vapor-phase epitaxy GaN films exposed to Ar{sup +} irradiation, employing Schottky barrier diodes. The Ar{sup +} irradiation tends to largely increase the effective carrier concentration in the near surface region of GaN up to ∼25 nm, due to the generation of donor-type N vacancy defects, compared to the original value before the irradiation. More interestingly, acceptor-type deep-level defects are found to be formed at ∼2.1, ∼2.9, and ∼3.2 eV below the conduction band in the subsequently deeper region, in which Ga vacancies introduced by the Ar{sup +} irradiation are considered to be in-diffused and immediately combined with hydrogen. These N vacancies and hydrogenated Ga vacancies formed are dominantly responsible for changing the depth profiles of the effective carrier concentration via the carrier generation, the carrier trapping, and/or carrier compensation.

  18. Effect of Fe-doping on nonlinear optical responses and carrier trapping dynamics in GaN single crystals

    SciTech Connect

    Fang, Yu; Yang, Junyi; Yang, Yong; Zhou, Feng; Wu, Xingzhi; Xiao, Zhengguo; Song, Yinglin

    2015-08-03

    We presented a quantitative study on the Fe-doping concentration dependence of optical nonlinearities and ultrafast carrier dynamics in Fe-doped GaN (GaN:Fe) single crystals using picosecond Z-scan and femtosecond pump-probe with phase object techniques under two-photon excitation. In contrast to the two-photon absorption that was found to be independent on the Fe-doping, the nonlinear refraction decreased with the Fe concentration due to the fast carrier trapping effect of Fe{sup 3+}/Fe{sup 2+} deep acceptors, which simultaneously acted as an efficient non-radiative recombination channels for excess carriers. Remarkably, compared to that of Si-doped GaN bulk crystal, the free-carrier refraction effect in GaN:Fe crystals was found to be enhanced considerably since Fe-doping and the effective carrier lifetime (∼10 ps) could be tuned over three orders of magnitude at high Fe-doping level of 1 × 10{sup 19 }cm{sup −3}.

  19. Study of the effects of GaN buffer layer quality on the dc characteristics of AlGaN/GaN high electron mobility transistors

    DOE PAGES [OSTI]

    Ahn, Shihyun; Zhu, Weidi; Dong, Chen; Le, Lingcong; Hwang, Ya-Hsi; Kim, Byung-Jae; Ren, Fan; Pearton, Stephen J.; Lind, Aaron G.; Jones, Kevin S.; et al

    2015-04-21

    Here we studied the effect of buffer layer quality on dc characteristics of AlGaN/GaN high electron mobility (HEMTs). AlGaN/GaN HEMT structures with 2 and 5 μm GaN buffer layers on sapphire substrates from two different vendors with the same Al concentration of AlGaN were used. The defect densities of HEMT structures with 2 and 5 μm GaN buffer layer were 7 × 109 and 5 × 108 cm₋2, respectively, as measured by transmission electron microscopy. There was little difference in drain saturation current or in transfer characteristics in HEMTs on these two types of buffer. However, there was no dispersionmore » observed on the nonpassivated HEMTs with 5 μm GaN buffer layer for gate-lag pulsed measurement at 100 kHz, which was in sharp contrast to the 71% drain current reduction for the HEMT with 2 μm GaN buffer layer.« less

  20. Study of the effects of GaN buffer layer quality on the dc characteristics of AlGaN/GaN high electron mobility transistors

    SciTech Connect

    Ahn, Shihyun; Zhu, Weidi; Dong, Chen; Le, Lingcong; Hwang, Ya-Hsi; Kim, Byung-Jae; Ren, Fan; Pearton, Stephen J.; Lind, Aaron G.; Jones, Kevin S.; Kravchenko, I. I.; Zhang, Ming-Lan

    2015-04-21

    Here we studied the effect of buffer layer quality on dc characteristics of AlGaN/GaN high electron mobility (HEMTs). AlGaN/GaN HEMT structures with 2 and 5 μm GaN buffer layers on sapphire substrates from two different vendors with the same Al concentration of AlGaN were used. The defect densities of HEMT structures with 2 and 5 μm GaN buffer layer were 7 × 109 and 5 × 108 cm₋2, respectively, as measured by transmission electron microscopy. There was little difference in drain saturation current or in transfer characteristics in HEMTs on these two types of buffer. However, there was no dispersion observed on the nonpassivated HEMTs with 5 μm GaN buffer layer for gate-lag pulsed measurement at 100 kHz, which was in sharp contrast to the 71% drain current reduction for the HEMT with 2 μm GaN buffer layer.

  1. Increased p-type conductivity through use of an indium surfactant in the growth of Mg-doped GaN

    SciTech Connect

    Kyle, Erin C. H. Kaun, Stephen W.; Young, Erin C.; Speck, James S.

    2015-06-01

    We have examined the effect of an indium surfactant on the growth of p-type GaN by ammonia-based molecular beam epitaxy. p-type GaN was grown at temperatures ranging from 700 to 780 °C with and without an indium surfactant. The Mg concentration in all films in this study was 4.5–6 × 10{sup 19} cm{sup −3} as measured by secondary ion mass spectroscopy. All p-type GaN films grown with an indium surfactant had higher p-type conductivities and higher hole concentrations than similar films grown without an indium surfactant. The lowest p-type GaN room temperature resistivity was 0.59 Ω-cm, and the highest room temperature carrier concentration was 1.6 × 10{sup 18} cm{sup −3}. Fits of the temperature-dependent carrier concentration data showed a one to two order of magnitude lower unintentional compensating defect concentration in samples grown with the indium surfactant. Samples grown at higher temperature had a lower active acceptor concentration. Improvements in band-edge luminescence were seen by cathodoluminescence for samples grown with the indium surfactant, confirming the trends seen in the Hall data.

  2. Effect of AlN buffer layer properties on the morphology and polarity of GaN nanowires grown by molecular beam epitaxy

    SciTech Connect

    Brubaker, Matt D.; Rourke, Devin M.; Sanford, Norman A.; Bertness, Kris A.; Bright, Victor M.

    2011-09-01

    Low-temperature AlN buffer layers grown via plasma-assisted molecular beam epitaxy on Si (111) were found to significantly affect the subsequent growth morphology of GaN nanowires. The AlN buffer layers exhibited nanowire-like columnar protrusions, with their size, shape, and tilt determined by the AlN V/III flux ratio. GaN nanowires were frequently observed to adopt the structural characteristics of the underlying AlN columns, including the size and the degree of tilt. Piezoresponse force microscopy and polarity-sensitive etching indicate that the AlN films and the protruding columns have a mixed crystallographic polarity. Convergent beam electron diffraction indicates that GaN nanowires are Ga-polar, suggesting that Al-polar columns are nanowire nucleation sites for Ga-polar nanowires. GaN nanowires of low density could be grown on AlN buffers that were predominantly N-polar with isolated Al-polar columns, indicating a high growth rate for Ga-polar nanowires and suppressed growth of N-polar nanowires under typical growth conditions. AlN buffer layers grown under slightly N-rich conditions (V/III flux ratio = 1.0 to 1.3) were found to provide a favorable growth surface for low-density, coalescence-free nanowires.

  3. ALD TiO2-Al2O3 Stack: An Improved Gate Dielectrics on Ga-polar GaN MOSCAPs

    DOE PAGES [OSTI]

    Wei, Daming; Edgar, James H.; Briggs, Dayrl P.; Srijanto, Bernadeta R.; Retterer, Scott T.; Meyer, III, Harry M.

    2014-10-15

    This research focuses on the benefits and properties of TiO2-Al2O3 nano-stack thin films deposited on Ga2O3/GaN by plasma-assisted atomic layer deposition (PA-ALD) for gate dielectric development. This combination of materials achieved a high dielectric constant, a low leakage current, and a low interface trap density. Correlations were sought between the films’ structure, composition, and electrical properties. The gate dielectrics were approximately 15 nm thick and contained 5.1 nm TiO2, 7.1 nm Al2O3 and 2 nm Ga2O3 as determined by spectroscopic ellipsometry. The interface carbon concentration, as measured by x-ray photoelectron spectroscopy (XPS) depth profile, was negligible for GaN pretreated bymore » thermal oxidation in O2 for 30 minutes at 850°C. The RMS roughness slightly increased after thermal oxidation and remained the same after ALD of the nano-stack, as determined by atomic force microscopy. The dielectric constant of TiO2-Al2O3 on Ga2O3/GaN was increased to 12.5 compared to that of pure Al2O3 (8~9) on GaN. In addition, the nano-stack's capacitance-voltage (C-V) hysteresis was small, with a total trap density of 8.74 × 1011 cm-2. The gate leakage current density (J=2.81× 10-8 A/cm2) was low at +1 V gate bias. These results demonstrate the promising potential of plasma ALD deposited TiO2/Al2O3 for serving as the gate oxide on Ga2O3/GaN based MOS devices.« less

  4. Temperature-dependent Raman and ultraviolet photoelectron spectroscopy studies on phase transition behavior of VO{sub 2} films with M1 and M2 phases

    SciTech Connect

    Okimura, Kunio Hanis Azhan, Nurul; Hajiri, Tetsuya; Kimura, Shin-ichi; Zaghrioui, Mustapha; Sakai, Joe

    2014-04-21

    Structural and electronic phase transitions behavior of two polycrystalline VO{sub 2} films, one with pure M1 phase and the other with pure M2 phase at room temperature, were investigated by temperature-controlled Raman spectroscopy and ultraviolet photoelectron spectroscopy (UPS). We observed characteristic transient dynamics in which the Raman modes at 195 cm{sup −1} (V-V vibration) and 616 cm{sup −1} (V-O vibration) showed remarkable hardening along the temperature in M1 phase film, indicating the rearrangements of V-V pairs and VO{sub 6} octahedra. It was also shown that the M1 Raman mode frequency approached those of invariant M2 peaks before entering rutile phase. In UPS spectra with high energy resolution of 0.03 eV for the M2 phase film, narrower V{sub 3d} band was observed together with smaller gap compared to those of M1 phase film, supporting the nature of Mott insulator of M2 phase even in the polycrystalline film. Cooperative behavior of lattice rearrangements and electronic phase transition was suggested for M1 phase film.

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

    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...

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

    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...

  7. Role of an ultra-thin AlN/GaN superlattice interlayer on the strain engineering of GaN films grown on Si(110) and Si(111) substrates by plasma-assisted molecular beam epitaxy

    SciTech Connect

    Shen, X. Q.; Takahashi, T.; Matsuhata, H.; Ide, T.; Shimizu, M.; Rong, X.; Chen, G.; Wang, X. Q.; Shen, B.

    2013-12-02

    We investigate the role of an ultra-thin AlN/GaN superlattice interlayer (SL-IL) on the strain engineering of the GaN films grown on Si(110) and Si(111) substrates by plasma-assisted molecular beam epitaxy. It is found that micro-cracks limitted only at the SL-IL position are naturally generated. These micro-cracks play an important role in relaxing the tensile strain caused by the difference of the coefficient of thermal expansion between GaN and Si and keeping the residual strain in the crack-free GaN epilayers resulted from the SL-IL during the growth. The mechanism understanding of the strain modulation by the SL-IL in the GaN epilayers grown on Si substrates makes it possible to design new heterostructures of III-nitrides for optic and electronic device applications.

  8. Climate protection in Germany`s bilateral development co-operation with the People`s Republic of China

    SciTech Connect

    Schneider, A.

    1996-12-31

    For globally sustainable development to be achieved, three concerns are central: productive economic growth, social justice and ecological sustainability. Development co-operation supports the realisation of these three goals in partner countries by helping to alleviate poverty, promote economic growth through private-sector development and protect vital natural resources. The aim of globally sustainable development can only be achieved if industrial countries too implement necessary reforms and structural adjustments at every level. Co-operation efforts with partners must therefore be complemented by coherent policies at home. This is a matter of credibility, but also of developmental far-sightedness. Internal reforms in the industrial countries secure financial leeway for their providing foreign assistance in the longer term. Environmental and resource protection as a focal point of Germany`s development co-operation with the PRC aims to preserve vital natural resources, shape economic development in their partner countries in an ecologically sound manner and put China in a position to participate in global endeavours to protect the environment. Climate protection measures figure prominently in this area. This is justified given China`s share of global CO{sub 2} emissions and the potential for energy-saving measures and measures to increase power intensity. This potential is derived primarily from the possibility of using energy-efficient technologies, increasing the relatively low energy prices and making use of renewable sources of energy.

  9. Formation of GaN quantum dots by molecular beam epitaxy using NH{sub 3} as nitrogen source

    SciTech Connect

    Damilano, B. Brault, J.; Massies, J.

    2015-07-14

    Self-assembled GaN quantum dots (QDs) in Al{sub x}Ga{sub 1−x}N (0.3 ≤ x ≤ 1) were grown on c-plane sapphire and Si (111) substrates by molecular beam epitaxy using ammonia as nitrogen source. The QD formation temperature was varied from 650 °C to 800 °C. Surprisingly, the density and size of QDs formed in this temperature range are very similar. This has been explained by considering together experimental results obtained from reflection high-energy electron diffraction, atomic force microscopy, and photoluminescence to discuss the interplay between thermodynamics and kinetics in the QD formation mechanisms. Finally, possible ways to better control the QD optical properties are proposed.

  10. Phase-field simulations of GaN growth by selective area epitaxy from complex mask geometries

    SciTech Connect

    Aagesen, Larry K.; Thornton, Katsuyo; Coltrin, Michael E.; Han, Jung

    2015-05-21

    Three-dimensional phase-field simulations of GaN growth by selective area epitaxy were performed. The model includes a crystallographic-orientation-dependent deposition rate and arbitrarily complex mask geometries. The orientation-dependent deposition rate can be determined from experimental measurements of the relative growth rates of low-index crystallographic facets. Growth on various complex mask geometries was simulated on both c-plane and a-plane template layers. Agreement was observed between simulations and experiment, including complex phenomena occurring at the intersections between facets. The sources of the discrepancies between simulated and experimental morphologies were also investigated. The model provides a route to optimize masks and processing conditions during materials synthesis for solar cells, light-emitting diodes, and other electronic and opto-electronic applications.

  11. Phase-field simulations of GaN growth by selective area epitaxy on complex mask geometries

    DOE PAGES [OSTI]

    Aagesen, Larry K.; Coltrin, Michael Elliott; Han, Jung; Thornton, Katsuyo

    2015-05-15

    Three-dimensional phase-field simulations of GaN growth by selective area epitaxy were performed. Furthermore, this model includes a crystallographic-orientation-dependent deposition rate and arbitrarily complex mask geometries. The orientation-dependent deposition rate can be determined from experimental measurements of the relative growth rates of low-index crystallographic facets. Growth on various complex mask geometries was simulated on both c-plane and a-plane template layers. Agreement was observed between simulations and experiment, including complex phenomena occurring at the intersections between facets. The sources of the discrepancies between simulated and experimental morphologies were also investigated. We found that the model provides a route to optimize masks andmore » processing conditions during materials synthesis for solar cells, light-emitting diodes, and other electronic and opto-electronic applications.« less

  12. Phase-field simulations of GaN growth by selective area epitaxy on complex mask geometries

    SciTech Connect

    Aagesen, Larry K.; Coltrin, Michael Elliott; Han, Jung; Thornton, Katsuyo

    2015-05-15

    Three-dimensional phase-field simulations of GaN growth by selective area epitaxy were performed. Furthermore, this model includes a crystallographic-orientation-dependent deposition rate and arbitrarily complex mask geometries. The orientation-dependent deposition rate can be determined from experimental measurements of the relative growth rates of low-index crystallographic facets. Growth on various complex mask geometries was simulated on both c-plane and a-plane template layers. Agreement was observed between simulations and experiment, including complex phenomena occurring at the intersections between facets. The sources of the discrepancies between simulated and experimental morphologies were also investigated. We found that the model provides a route to optimize masks and processing conditions during materials synthesis for solar cells, light-emitting diodes, and other electronic and opto-electronic applications.

  13. Polarity characterization by anomalous x-ray dispersion of ZnO films and GaN lateral polar structures

    SciTech Connect

    Shelton, Christopher T.; Sachet, Edward; Paisley, Elizabeth A.; Hoffmann, Marc P.; Rajan, Joseph; Collazo, Ramn; Sitar, Zlatko; Maria, Jon-Paul

    2014-01-28

    We demonstrate the use of anomalous x-ray scattering of constituent cations at their absorption edge, in a conventional Bragg-Brentano diffractometer, to measure absolutely and quantitatively the polar orientation and polarity fraction of unipolar and mixed polar wurtzitic crystals. In one set of experiments, the gradual transition between c+ and c? polarity of epitaxial ZnO films on sapphire as a function of MgO buffer layer thickness is monitored quantitatively, while in a second experiment, we map the polarity of a lateral polar homojunction in GaN. The dispersion measurements are compared with piezoforce microscopy images, and we demonstrate how x-ray dispersion and scanning probe methods can provide complementary information that can discriminate between polarity fractions at a material surface and polarity fractions averaged over the film bulk.

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

    SciTech Connect

    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.

  15. Carbon doped GaN buffer layer using propane for high electron mobility transistor applications: Growth and device results

    SciTech Connect

    Li, X.; Nilsson, D.; Danielsson, Ö.; Pedersen, H.; Janzén, E.; Forsberg, U.; Bergsten, J.; Rorsman, N.

    2015-12-28

    The creation of a semi insulating (SI) buffer layer in AlGaN/GaN High Electron Mobility Transistor (HEMT) devices is crucial for preventing a current path beneath the two-dimensional electron gas (2DEG). In this investigation, we evaluate the use of a gaseous carbon gas precursor, propane, for creating a SI GaN buffer layer in a HEMT structure. The carbon doped profile, using propane gas, is a two stepped profile with a high carbon doping (1.5 × 10{sup 18 }cm{sup −3}) epitaxial layer closest to the substrate and a lower doped layer (3 × 10{sup 16 }cm{sup −3}) closest to the 2DEG channel. Secondary Ion Mass Spectrometry measurement shows a uniform incorporation versus depth, and no memory effect from carbon doping can be seen. The high carbon doping (1.5 × 10{sup 18 }cm{sup −3}) does not influence the surface morphology, and a roughness root-mean-square value of 0.43 nm is obtained from Atomic Force Microscopy. High resolution X-ray diffraction measurements show very sharp peaks and no structural degradation can be seen related to the heavy carbon doped layer. HEMTs are fabricated and show an extremely low drain induced barrier lowering value of 0.1 mV/V, demonstrating an excellent buffer isolation. The carbon doped GaN buffer layer using propane gas is compared to samples using carbon from the trimethylgallium molecule, showing equally low leakage currents, demonstrating the capability of growing highly resistive buffer layers using a gaseous carbon source.

  16. East Germany struggles to clean its air and water

    SciTech Connect

    Cherfas, J.

    1990-04-20

    East Germans are working hard on a strategy to improve their polluted environment. Industrial plants are largely responsible for this pollution. A shroud of haze veils the suburbs of East Berlin. Far to the south the giant power plants around Leipzig pour more dust and sulfur dioxide into the air than in any other country in Europe. More than 90% of the country's electricity comes from brown coal, accompanied by prodigious quantities of dust and sulfur dioxide: almost 6 million tones of sulfur dioxide and more than 2 million tones of dust in 1988. East Germany enjoys some of the cheapest energy in the world, and the world's third highest energy consumption per capita, behind the United States, and Canada. Naturally, is also suffers air quality and health problems. The country is trying to cut down on consumption and clean up on generation. Actually, water quality is the number one priority, which unlike air is in very short supply.

  17. Germany, garbage, and the green dot: Challenging the throwaway society

    SciTech Connect

    Fishbein, B.K.

    1994-09-01

    For US policymakers and citizens who are grappling with the question of how to handle this country's mounting municipal garbage and commercial wastes, this report offers a revolutionary approach taken by Germany to promote both recycling and source reduction. The sweeping new German legislation is stimulating industry efforts to reduce packaging and product waste by requiring that the businesses producing packages and products be financially responsible for taking back their used materials and recycling, reusing or disposing of them. This report describes what Germans have done in solid waste policies, the difficulties they are confronting and the impact on wastes to date. It discusses the environmental problems that the US and other industrialized countries face, identifies practical solutions: programs and policies that work to conserve our valuable air, land, water and natural resources and enable us to live and do business less wastefully.

  18. Large Scale Wind and Solar Integration in Germany

    SciTech Connect

    Ernst, Bernhard; Schreirer, Uwe; Berster, Frank; Pease, John; Scholz, Cristian; Erbring, Hans-Peter; Schlunke, Stephan; Makarov, Yuri V.

    2010-02-28

    This report provides key information concerning the German experience with integrating of 25 gigawatts of wind and 7 gigawatts of solar power capacity and mitigating its impacts on the electric power system. The report has been prepared based on information provided by the Amprion GmbH and 50Hertz Transmission GmbH managers and engineers to the Bonneville Power Administration (BPA) and Pacific Northwest National Laboratory representatives during their visit to Germany in October 2009. The trip and this report have been sponsored by the BPA Technology Innovation office. Learning from the German experience could help the Bonneville Power Administration engineers to compare and evaluate potential new solutions for managing higher penetrations of wind energy resources in their control area. A broader dissemination of this experience will benefit wind and solar resource integration efforts in the United States.

  19. Proposals in for Czech firms; cooperation likely with eastern Germany

    SciTech Connect

    Alperowicz, N.

    1993-02-10

    Two Western groups - Shell and a consortium made up of Agip, Conoco, and Total - have offered to buy the refining operations of Chemopetrol Litvinov and Kaucuk Kralupy, both in the Czech republic. Meanwhile, Amoco, Neste, and PCD are looking at the possibility of acquiring some of the plastics plants at Litvinov. Amoco is interested in the polypropylene operations, Neste in polyethylene, and PCD in both. The two Czech firms are included in the second wave of privatization, which will begin in midyear. So far, there have been no offers for the 80,000-m.t./year polystyrene and 60,000-m.t./year styrene butadiene rubber operations belonging to Kralupy, although Atochem representatives recently visited the plants. Litvinov is carrying out revamping operations at its core unit, a 12-year-old, 450,000-m.t./year ethylene plant. The plant, currently running at 400,000 m.t./year, supplies downstream plants, Neratovice, and sells on the export markets. An existing ethylene pipeline between Litvinov and Bohlen in eastern Germany, which used to supply an average 100,000 m.t./year of ethylene to Bohen in exchange for naphtha, is virtually unused. One proposal involves reactivating this exchange to secure ethylene feedstock for plants in eastern Germany. According to some sources, a preliminary decision has been made to shut down the 100,000-m.t./year ethylene plant at Leuna and possibly to expand the Bohlen cracker by 100,000 m.t./year, to 400,000 m.t./year by the late 1990s.

  20. Zero lattice mismatch and twin-free single crystalline ScN buffer layers for GaN growth on silicon

    SciTech Connect

    Lupina, L.; Zoellner, M. H.; Dietrich, B.; Capellini, G.; Niermann, T.; Lehmann, M.; Thapa, S. B.; Haeberlen, M.; Storck, P.; Schroeder, T.

    2015-11-16

    We report the growth of thin ScN layers deposited by plasma-assisted molecular beam epitaxy on Sc{sub 2}O{sub 3}/Y{sub 2}O{sub 3}/Si(111) substrates. Using x-ray diffraction, Raman spectroscopy, and transmission electron microscopy, we find that ScN films grown at 600 °C are single crystalline, twin-free with rock-salt crystal structure, and exhibit a direct optical band gap of 2.2 eV. A high degree of crystalline perfection and a very good lattice matching between ScN and GaN (misfit < 0.1%) makes the ScN/Sc{sub 2}O{sub 3}/Y{sub 2}O{sub 3} buffer system a very promising template for the growth of high quality GaN layers on silicon.

  1. Temperature dependent dielectric function and the E{sub 0} critical points of hexagonal GaN from 30 to 690 K

    SciTech Connect

    Kim, Tae Jung Hwang, Soon Yong; Byun, Jun Seok; Barange, Nilesh S.; Park, Han Gyeol; Dong Kim, Young

    2014-02-15

    The complex dielectric function ? and the E{sub 0} excitonic and band-edge critical-point structures of hexagonal GaN are reported for temperatures from 30 to 690 K and energies from 0.74 to 6.42 eV, obtained by rotating-compensator spectroscopic ellipsometry on a 1.9 ?m thick GaN film deposited on a c-plane (0001) sapphire substrate by molecular beam epitaxy. Direct inversion and B-splines in a multilayer-structure calculation were used to extract the optical properties of the film from the measured pseudodielectric function ???. At low temperature sharp E{sub 0} excitonic and critical-point interband transitions are separately observed. Their temperature dependences were determined by fitting the data to the empirical Varshni relation and the phenomenological expression that contains the Bose-Einstein statistical factor.

  2. Structural anisotropic properties of a-plane GaN epilayers grown on r-plane sapphire by molecular beam epitaxy

    SciTech Connect

    Lotsari, A.; Kehagias, Th.; Katsikini, M.; Arvanitidis, J.; Ves, S.; Komninou, Ph.; Dimitrakopulos, G. P.; Tsiakatouras, G.; Tsagaraki, K.; Georgakilas, A.; Christofilos, D.

    2014-06-07

    Heteroepitaxial non-polar III-Nitride layers may exhibit extensive anisotropy in the surface morphology and the epilayer microstructure along distinct in-plane directions. The structural anisotropy, evidenced by the M-shape dependence of the (112{sup }0) x-ray rocking curve widths on the beam azimuth angle, was studied by combining transmission electron microscopy observations, Raman spectroscopy, high resolution x-ray diffraction, and atomic force microscopy in a-plane GaN epilayers grown on r-plane sapphire substrates by plasma-assisted molecular beam epitaxy (PAMBE). The structural anisotropic behavior was attributed quantitatively to the high dislocation densities, particularly the Frank-Shockley partial dislocations that delimit the I{sub 1} intrinsic basal stacking faults, and to the concomitant plastic strain relaxation. On the other hand, isotropic samples exhibited lower dislocation densities and a biaxial residual stress state. For PAMBE growth, the anisotropy was correlated to N-rich (or Ga-poor) conditions on the surface during growth, that result in formation of asymmetric a-plane GaN grains elongated along the c-axis. Such conditions enhance the anisotropy of gallium diffusion on the surface and reduce the GaN nucleation rate.

  3. Valorization of GaN based metal-organic chemical vapor deposition dust a semiconductor power device industry waste through mechanochemical oxidation and leaching: A sustainable green process

    SciTech Connect

    Swain, Basudev; Mishra, Chinmayee; Lee, Chan Gi; Park, Kyung-Soo; Lee, Kun-Jae

    2015-07-15

    Dust generated during metal organic vapor deposition (MOCVD) process of GaN based semiconductor power device industry contains significant amounts of gallium and indium. These semiconductor power device industry wastes contain gallium as GaN and Ga{sub 0.97}N{sub 0.9}O{sub 0.09} is a concern for the environment which can add value through recycling. In the present study, this waste is recycled through mechanochemical oxidation and leaching. For quantitative recovery of gallium, two different mechanochemical oxidation leaching process flow sheets are proposed. In one process, first the Ga{sub 0.97}N{sub 0.9}O{sub 0.09} of the MOCVD dust is leached at the optimum condition. Subsequently, the leach residue is mechanochemically treated, followed by oxidative annealing and finally re-leached. In the second process, the MOCVD waste dust is mechanochemically treated, followed by oxidative annealing and finally leached. Both of these treatment processes are competitive with each other, appropriate for gallium leaching and treatment of the waste MOCVD dust. Without mechanochemical oxidation, 40.11 and 1.86 w/w% of gallium and Indium are leached using 4 M HCl, 100 °C and pulp density of 100 kg/m{sup 3,} respectively. After mechanochemical oxidation, both these processes achieved 90 w/w% of gallium and 1.86 w/w% of indium leaching at their optimum condition. - Highlights: • Waste MOCVD dust is treated through mechanochemical leaching. • GaN is hardly leached, and converted to NaGaO{sub 2} through ball milling and annealing. • Process for gallium recovery from waste MOCVD dust has been developed. • Thermal analysis and phase properties of GaN to Ga{sub 2}O{sub 3} and GaN to NaGaO{sub 2} is revealed. • Solid-state chemistry involved in this process is reported.

  4. A complex investigation of building sandstones from Saxony (Germany)

    SciTech Connect

    Goetze, Jens Siedel, Heiner

    2007-11-15

    The present paper provides a methodology for the investigation and characterization of building sandstones. This analytical scheme was designed for distinguishing mature arenites, which in general show very similar properties and are difficult to distinguish. This is shown for Cretaceous sandstones from various occurrences in Saxony (Germany), which have been used for centuries as building materials. The procedure is mainly based on the combination of macroscopic rock description, thin section polarizing microscopy (phase composition, texture, grain-size distribution) and cathodoluminescence (CL) microscopy (quartz types, feldspar and kaolinite content) coupled with image analysis, scanning electron microscopy (accessories, pore cement, diagenetic grain surface features), and analysis of pore space data. Sometimes, additional data from X-ray diffraction or chemical analyses (major and trace elements) can be used. Especially in the case of quartz rich arenites, CL is a powerful tool for provenance analysis. The detailed analysis of sandstone material in most cases allows us to assign historically used building material to a specific sandstone occurrence. These results are important for both interpreting the weathering behaviour of the building material and the conservation, reconstruction and stone replacement of historical monuments.

  5. Why Are Resiential PV Prices in Germany So Much Lower Than in the United States?

    Energy.gov [DOE]

    The U.S. Department of Energy (DOE) SunShot Initiative, in conjunction with the Lawrence Berkeley National Laboratory (LBNL) discusses the installed price of residential PV being significantly lower in Germany than in the United States.

  6. Microsoft Word - MOU Between DOE and Germany 9-15-11.doc

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    FOR IMMEDIATE RELEASE DOE Hosts German Energy Official, Signs MOU to Share WIPP Information CARLSBAD, N.M., September 15, 2011 - A high-ranking energy official from Germany formalized a partnership between her country and the United States during a recent visit to the Waste Isolation Pilot Plant (WIPP). Dr. Dorothee Műhl, Deputy Director General Manager of Germany's Federal Ministry of Economics and Technology (BMWi), and other German officials visited WIPP, the U.S. Department of Energy's

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

    SciTech Connect

    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} Ω 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} Ω 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.

  8. Measurement of the hot electron mean free path and the momentum relaxation rate in GaN

    SciTech Connect

    Suntrup, Donald J.; Gupta, Geetak; Li, Haoran; Keller, Stacia; Mishra, Umesh K.

    2014-12-29

    We present a method for measuring the mean free path and extracting the momentum relaxation time of hot electrons in GaN using the hot electron transistor (HET). In this device, electrons are injected over a high energy emitter barrier into the base where they experience quasi-ballistic transport well above the conduction band edge. After traversing the base, high energy electrons either surmount the base-collector barrier and become collector current or reflect off the barrier and become base current. We fabricate HETs with various base thicknesses and measure the common emitter transfer ratio (α) for each device. The mean free path is extracted by fitting α to a decaying exponential as a function of base width and the relaxation time is computed using a suitable injection velocity. For devices with an injection energy of ∼1 eV, we measure a hot electron mean free path of 14 nm and calculate a momentum relaxation time of 16 fs. These values are in agreement with theoretical calculations where longitudinal optical phonon scattering is the dominant momentum relaxation mechanism.

  9. Design, fabrication, and performance analysis of GaN vertical electron transistors with a buried p/n junction

    SciTech Connect

    Yeluri, Ramya Lu, Jing; Keller, Stacia; Mishra, Umesh K.; Hurni, Christophe A.; Browne, David A.; Speck, James S.; Chowdhury, Srabanti

    2015-05-04

    The Current Aperture Vertical Electron Transistor (CAVET) combines the high conductivity of the two dimensional electron gas channel at the AlGaN/GaN heterojunction with better field distribution offered by a vertical design. In this work, CAVETs with buried, conductive p-GaN layers as the current blocking layer are reported. The p-GaN layer was regrown by metalorganic chemical vapor deposition and the subsequent channel regrowth was done by ammonia molecular beam epitaxy to maintain the p-GaN conductivity. Transistors with high ON current (10.9?kA/cm{sup 2}) and low ON-resistance (0.4 m? cm{sup 2}) are demonstrated. Non-planar selective area regrowth is identified as the limiting factor to transistor breakdown, using planar and non-planar n/p/n structures. Planar n/p/n structures recorded an estimated electric field of 3.1 MV/cm, while non-planar structures showed a much lower breakdown voltage. Lowering the p-GaN regrowth temperature improved breakdown in the non-planar n/p/n structure. Combining high breakdown voltage with high current will enable GaN vertical transistors with high power densities.

  10. Final decision document for the interim response action at the M-1 Settling Basins, Rocky Mountain Arsenal, Version 4. 0. Final report

    SciTech Connect

    Not Available

    1990-03-01

    The objective of the interim response action at the M-1 settling basins is to mitigate the threat of release of contaminants from the basins which are a direct source of as contamination to the ground water. The proposed IRA consists of (1) construction of a 360 degree subsurface barrier and (2) treatment of the wastes with in-situ vitrification. This decision document provides summaries of: (1) alternative technologies considered; (2) significant events leading to the initiation of the IRA; (3) the IRA project; and (4) applicable or relevant and appropriate requirements, standards, criteria, and limitations (ARAR's) associated with the program.

  11. Psychological effects of sustained operations in a simulated NBC (nuclear, biological or chemical) environment on M1 tank crews. Technical report, May-June 1985

    SciTech Connect

    Munro, I.; Rauch, T.M.; Banderet, L.E.; Lussier, A.R.; Tharion, W.J.

    1987-07-03

    Forty-eight M1 crewmen were tested in a temperate climate under conditions simulating 72-hour operations in an area contaminated with chemical agents. Over 50% of the crewman voluntarily withdrew from the test, and maximum unit endurance did not exceed 32 hours. Two problems were found to be related to endurance failure. Soldiers who withdrew reported more intense symptoms associated with respiratory distress than did those who remained in the test. In addition, soldiers who withdrew experienced greater cognitive difficulties. Near-term countermeasures, assessed in some test iterations, showed no significant endurance-extending effects. Alternative solutions based on the identified problems were proposed.

  12. Safety Analysis Report for Packaging (SARP): Model AL-M1 nuclear packaging (DOE C of C No. USA/9507/BLF)

    SciTech Connect

    Coleman, H.L.; Whitney, M.A.; Williams, M.A.; Alexander, B.M.; Shapiro, A.

    1987-11-24

    This Safety Analysis Report for Packaging (SARP) satisfies the request of the US Department of Energy for a formal safety analysis of the shipping container identified as USA/9507/BLF, also called AL-M1, configuration 5. This report makes available to all potential users the technical information and the limits pertinent to the construction and use of the shipping containers. It includes discussions of structural integrity, thermal resistance, radiation shielding and radiological safety, nuclear criticality safety, and quality control. A complete physical and technical description of the package is presented. The package consists of an inner container centered within an insulated steel drum. The configuration-5 package contains tritiated water held on sorbent material. There are two other AL-M1 packages, designated configurations 1 and 3. These use the same insulated outer drum, but licensing of these containers will not be addressed in this SARP. Design and development considerations, the tests and evaluations required to prove the ability of the container to withstand normal transportation conditions, and the sequence of four hypothetical accident conditions (free drop, puncture, thermal, and water immersion) are discussed. Tables, graphs, dimensional sketches, photographs, technical references, loading and shipping procedures, Monsanto Research Corporation-Mound experience in using the containers, and a copy of the DOE/OSD/ALO Certificate of Compliance are included.

  13. 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

    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.

  14. Effects of substrate temperature, substrate orientation, and energetic atomic collisions on the structure of GaN films grown by reactive sputtering

    SciTech Connect

    Schiaber, Ziani S.; Lisboa-Filho, Paulo N.; Silva, Jos H. D. da; Leite, Douglas M. G.; Bortoleto, Jos R. R.

    2013-11-14

    The combined effects of substrate temperature, substrate orientation, and energetic particle impingement on the structure of GaN films grown by reactive radio-frequency magnetron sputtering are investigated. Monte-Carlo based simulations are employed to analyze the energies of the species generated in the plasma and colliding with the growing surface. Polycrystalline films grown at temperatures ranging from 500 to 1000 C clearly showed a dependence of orientation texture and surface morphology on substrate orientation (c- and a-plane sapphire) in which the (0001) GaN planes were parallel to the substrate surface. A large increase in interplanar spacing associated with the increase in both a- and c-parameters of the hexagonal lattice and a redshift of the optical bandgap were observed at substrate temperatures higher than 600 C. The results showed that the tensile stresses produced during the film's growth in high-temperature deposition ranges were much larger than the expected compressive stresses caused by the difference in the thermal expansion coefficients of the film and substrate in the cool-down process after the film growth. The best films were deposited at 500 C, 30 W and 600 C, 45 W, which corresponds to conditions where the out diffusion from the film is low. Under these conditions the benefits of the temperature increase because of the decrease in defect density are greater than the problems caused by the strongly strained lattice that occurr at higher temperatures. The results are useful to the analysis of the growth conditions of GaN films by reactive sputtering.

  15. Photo-induced water oxidation at the aqueous GaN (1010) interface: Deprotonation kinetics of the first proton-coupled electron-transfer step

    SciTech Connect

    Ertem, Mehmed Z.; Kharche, Neerav; Batista, Victor S.; Hybertsen, Mark S.; Tully, John C.; Muckerman, James T.

    2015-03-12

    Photoeclectrochemical water splitting plays a key role in a promising path to the carbon-neutral generation of solar fuels. Wurzite GaN and its alloys (e.g., GaN/ZnO and InGaN) are demonstrated photocatalysts for water oxidation, and they can drive the overall water splitting reaction when coupled with co-catalysts for proton reduction. In the present work, we investigate the water oxidation mechanism on the prototypical GaN (1010) surface using a combined ab initio molecular dynamics and molecular cluster model approach taking into account the role of water dissociation and hydrogen bonding within the first solvation shell of the hydroxylated surface. The investigation of free-energy changes for the four proton-coupled electron-transfer (PCET) steps of the water oxidation mechanism shows that the first PCET step for the conversion of Ga-OH to Ga-O?? requires the highest energy input. We further examine the sequential PCETs, with the proton transfer (PT) following the electron transfer (ET), and find that photo-generated holes localize on surface NH sites is thermodynamically more favorable than OH sites. However, proton transfer from OH sites with subsequent localization of holes on oxygen atoms is kinetically favored owing to hydrogen bonding interactions at the GaN (1010)water interface. We find that the deprotonation of surface OH sites is the limiting factor for the generation of reactive oxyl radical ion intermediates and consequently for water oxidation.

  16. Photo-induced water oxidation at the aqueous GaN (101¯0) interface: Deprotonation kinetics of the first proton-coupled electron-transfer step

    DOE PAGES [OSTI]

    Ertem, Mehmed Z.; Kharche, Neerav; Batista, Victor S.; Hybertsen, Mark S.; Tully, John C.; Muckerman, James T.

    2015-03-12

    Photoeclectrochemical water splitting plays a key role in a promising path to the carbon-neutral generation of solar fuels. Wurzite GaN and its alloys (e.g., GaN/ZnO and InGaN) are demonstrated photocatalysts for water oxidation, and they can drive the overall water splitting reaction when coupled with co-catalysts for proton reduction. In the present work, we investigate the water oxidation mechanism on the prototypical GaN (101¯0) surface using a combined ab initio molecular dynamics and molecular cluster model approach taking into account the role of water dissociation and hydrogen bonding within the first solvation shell of the hydroxylated surface. The investigation ofmore » free-energy changes for the four proton-coupled electron-transfer (PCET) steps of the water oxidation mechanism shows that the first PCET step for the conversion of –Ga-OH to –Ga-O˙⁻ requires the highest energy input. We further examine the sequential PCETs, with the proton transfer (PT) following the electron transfer (ET), and find that photo-generated holes localize on surface –NH sites is thermodynamically more favorable than –OH sites. However, proton transfer from –OH sites with subsequent localization of holes on oxygen atoms is kinetically favored owing to hydrogen bonding interactions at the GaN (101¯0)–water interface. We find that the deprotonation of surface –OH sites is the limiting factor for the generation of reactive oxyl radical ion intermediates and consequently for water oxidation.« less

  17. Mismatch relaxation by stacking fault formation of AlN islands in AlGaN/GaN structures on m-plane GaN substrates

    SciTech Connect

    Smalc-Koziorowska, Julita; Sawicka, Marta; Skierbiszewski, Czeslaw; Grzegory, Izabella

    2011-08-08

    We study the mismatch relaxation of 2-5 nm thin elongated AlN islands formed during growth of AlGaN on bulk m-plane GaN by molecular beam epitaxy. The relaxation of these m-plane AlN layers is anisotropic and occurs through the introduction of stacking faults in [0001] planes during island coalescence, while no relaxation is observed along the perpendicular [1120] direction. This anisotropy in the mismatch relaxation and the formation of stacking faults in the AlN islands are explained by the growth mode of the AlN platelets and their coalescence along the [0001] direction.

  18. Propane ammoxidation over the Mo-V-Te-Nb-O M1 phase: Reactivity of surface cations in hydrogen abstraction steps

    SciTech Connect

    Muthukumar, Kaliappan; Yu, Junjun; Xu, Ye; Guliants, Vadim V.

    2011-01-01

    Density functional theory calculations (GGA-PBE) have been performed to investigate the adsorption of C3 (propane, isopropyl, propene, and allyl) and H species on the proposed active center present in the surface ab planes of the bulk Mo-V-Te-Nb-O M1 phase in order to better understand the roles of the different surface cations in propane ammoxidation. Modified cluster models were employed to isolate the closely spaced V=O and Te=O from each other and to vary the oxidation state of the V cation. While propane and propene adsorb with nearly zero adsorption energy, the isopropyl and allyl radicals bind strongly to V=O and Te=O with adsorption energies, {Delta}E, being {le} -1.75 eV, but appreciably more weakly on other sites, such as Mo=O, bridging oxygen (Mo-O-V and Mo-O-Mo), and empty metal apical sites ({Delta}E > -1 eV). Atomic H binds more strongly to Te = O ({Delta}E {le} -3 eV) than to all the other sites, including V = O ({Delta}E = -2.59 eV). The reduction of surface oxo groups by dissociated H and their removal as water are thermodynamically favorable except when both H atoms are bonded to the same Te=O. Consistent with the strong binding of H, Te=O is markedly more active at abstracting the methylene H from propane (E{sub a} {le} 1.01 eV) than V = O (E{sub a} = 1.70 eV on V{sup 5+} = O and 2.13 eV on V{sup 4+} = O). The higher-than-observed activity and the loose binding of Te = O moieties to the mixed metal oxide lattice of M1 raise the question of whether active Te = O groups are in fact present in the surface ab planes of the M1 phase under propane ammoxidation conditions.

  19. Thermal stability of deep level defects induced by high energy proton irradiation in n-type GaN

    SciTech Connect

    Zhang, Z.; Farzana, E.; Sun, W. Y.; Arehart, A. R.; Ringel, S. A.; Chen, J.; Zhang, E. X.; Fleetwood, D. M.; Schrimpf, R. D.; McSkimming, B.; Kyle, E. C. H.; Speck, J. S.

    2015-10-21

    The impact of annealing of proton irradiation-induced defects in n-type GaN devices has been systematically investigated using deep level transient and optical spectroscopies. Moderate temperature annealing (>200–250 °C) causes significant reduction in the concentration of nearly all irradiation-induced traps. While the decreased concentration of previously identified N and Ga vacancy related levels at E{sub C} − 0.13 eV, 0.16 eV, and 2.50 eV generally followed a first-order reaction model with activation energies matching theoretical values for N{sub I} and V{sub Ga} diffusion, irradiation-induced traps at E{sub C} − 0.72 eV, 1.25 eV, and 3.28 eV all decrease in concentration in a gradual manner, suggesting a more complex reduction mechanism. Slight increases in concentration are observed for the N-vacancy related levels at E{sub C} − 0.20 eV and 0.25 eV, which may be due to the reconfiguration of other N-vacancy related defects. Finally, the observed reduction in concentrations of the states at E{sub C} − 1.25 and E{sub C} − 3.28 eV as a function of annealing temperature closely tracks the detailed recovery behavior of the background carrier concentration as a function of annealing temperature. As a result, it is suggested that these two levels are likely to be responsible for the underlying carrier compensation effect that causes the observation of carrier removal in proton-irradiated n-GaN.

  20. Upbend and M1 scissors mode in neutron-rich nuclei - consequences for r-process $$(n,\\gamma )$$ reaction rates

    DOE PAGES [OSTI]

    Larsen, A. C.; Goriely, S.; Bernstein, L. A.; Bleuel, D. L.; Bracco, A.; Brown, B. A.; Camera, F.; Eriksen, T. K.; Frauendorf, S.; Giacoppo, F.; et al

    2015-01-01

    An enhanced probability for low-energy γ-emission (upbend, Eγ < 3 MeV) at high excitation energies has been observed for several light and medium-mass nuclei close to the valley of stability. Also the M1 scissors mode seen in deformed nuclei increases the γ-decay probability for low-energy γ-rays (Eγ ≈ 2–3 MeV). These phenomena, if present in neutron-rich nuclei, have the potential to increase radiative neutron-capture rates relevant for the r-process. Furthermore, the experimental and theoretical status of the upbend is discussed, and preliminary calculations of (n,γ) reaction rates for neutron-rich, mid-mass nuclei including the scissors mode are shown.

  1. The influenza fingerprints: NS1 and M1 proteins contribute to specific host cell ultrastructure signatures upon infection by different influenza A viruses

    SciTech Connect

    Terrier, Olivier; Moules, Vincent; Carron, Coralie; Cartet, Gaeelle; Frobert, Emilie; Yver, Matthieu; Traversier, Aurelien; Wolff, Thorsten; Naffakh, Nadia; and others

    2012-10-10

    Influenza A are nuclear replicating viruses which hijack host machineries in order to achieve optimal infection. Numerous functional virus-host interactions have now been characterized, but little information has been gathered concerning their link to the virally induced remodeling of the host cellular architecture. In this study, we infected cells with several human and avian influenza viruses and we have analyzed their ultrastructural modifications by using electron and confocal microscopy. We discovered that infections lead to a major and systematic disruption of nucleoli and the formation of a large number of diverse viral structures showing specificity that depended on the subtype origin and genomic composition of viruses. We identified NS1 and M1 proteins as the main actors in the remodeling of the host ultra-structure and our results suggest that each influenza A virus strain could be associated with a specific cellular fingerprint, possibly correlated to the functional properties of their viral components.

  2. STEM HAADF Image Simulation of the Orthorhombic M1 Phase in the Mo-V-Nb-Te-O Propane Oxidation Catalyst

    SciTech Connect

    D Blom; X Li; S Mitra; T Vogt; D Buttrey

    2011-12-31

    A full frozen phonon multislice simulation of high angle annular dark field scanning transmission electron microscopy (HAADF STEM) images from the M1 phase of the Mo-V-Nb-Te-O propane oxidation catalyst has been performed by using the latest structural model obtained using the Rietveld method. Simulated contrast results are compared with experimental HAADF images. Good agreement is observed at ring sites, however significant thickness dependence is noticed at the linking sites. The remaining discrepancies between the model based on Rietveld refinement and image simulations indicate that the sampling of a small volume element in HAADF STEM and averaging elemental contributions of a disordered site in a crystal slab by using the virtual crystal approximation might be problematic, especially if there is preferential Mo/V ordering near the (001) surface.

  3. Search for 14.4-KeV Solar Axions Emitted in the M1-Transition of Fe-57 Nuclei with CAST

    SciTech Connect

    Andriamonje, S.; Aune, S.; Autiero, D.; Barth, K.; Belov, A.; Beltran, B.; Brauninger, H.; Carmona, J.M.; Cebrian, S.; Collar, J.I.; Dafni, T.; Davenport, M.; Di Lella, L.; Eleftheriadis, C.; Englhauser, J.; Fanourakis, G.; Ferrer-Ribas, E.; Fischer, H.; Franz, J.; Friedrich, P.; Geralis, T.; /Democritos Nucl. Res. Ctr. /DAPNIA, Saclay /Moscow, INR /Zaragoza U. /British Columbia U. /Freiburg U. /Darmstadt, Tech. Hochsch. /DAPNIA, Saclay /Zaragoza U. /Frankfurt U. /Boskovic Inst., Zagreb /Freiburg U. /Munich, Max Planck Inst. /Boskovic Inst., Zagreb /Democritos Nucl. Res. Ctr. /Darmstadt, Tech. Hochsch. /Garching, Max Planck Inst., MPE /Boskovic Inst., Zagreb /CERN /Aristotle U., Thessaloniki /Boskovic Inst., Zagreb /Munich, Max Planck Inst. /Zaragoza U. /Chicago U., EFI /Chicago U., KICP /Stanford U., Phys. Dept. /SLAC /Zaragoza U. /CERN /DAPNIA, Saclay /CERN /Munich, Max Planck Inst. /Darmstadt, Tech. Hochsch. /Zaragoza U. /Aristotle U., Thessaloniki /Patras U. /Brookhaven /CERN /Munich, Max Planck Inst. /CERN /Chicago U., EFI /Chicago U., KICP /Zaragoza U. /Freiburg U. /CERN /CERN /Patras U.

    2011-12-02

    We have searched for 14.4 keV solar axions or more general axion-like particles (ALPs), that may be emitted in the M1 nuclear transition of 57Fe, by using the axion-to-photon conversion in the CERN Axion Solar Telescope (CAST) with evacuated magnet bores (Phase I). From the absence of excess of the monoenergetic X-rays when the magnet was pointing to the Sun, we set model-independent constraints on the coupling constants of pseudoscalar particles that couple to two photons and to a nucleon g{sub ay}|-1.19g{sub aN}{sup 0}+g{sub aN}{sup 3}| < 1.36 x 10{sup -16} GeV{sup -1} for ma < 0.03 eV at the 95% confidence level.

  4. Trap states in enhancement-mode double heterostructures AlGaN/GaN high electron mobility transistors with different GaN channel layer thicknesses

    SciTech Connect

    He, Yunlong; Wang, Chong Li, Xiangdong; Zhao, Shenglei; Mi, Minhan; Pei, Jiuqing; Zhang, Jincheng; Hao, Yue; Li, Peixian; Ma, Xiaohua

    2015-08-10

    This is the report on trap states in enhancement-mode AlGaN/GaN/AlGaN double heterostructures high electron mobility transistors by fluorine plasma treatment with different GaN channel layer thicknesses. Compared with the thick GaN channel layer sample, the thin one has smaller 2DEG concentration, lower electron mobility, lower saturation current, and lower peak transconductance, but it has a higher threshold voltage of 1.2 V. Deep level transient spectroscopy measurements are used to obtain the accurate capture cross section of trap states. By frequency dependent capacitance and conductance measurements, the trap state density of (1.98–2.56) × 10{sup 12 }cm{sup −2} eV{sup −1} is located at E{sub T} in a range of (0.37–0.44) eV in the thin sample, while the trap state density of (2.3–2.92) × 10{sup 12 }cm{sup −2} eV{sup −1} is located at E{sub T} in a range of (0.33–0.38) eV in the thick one. It indicates that the trap states in the thin sample are deeper than those in the thick one.

  5. (11-22) semipolar InGaN emitters from green to amber on overgrown GaN on micro-rod templates

    SciTech Connect

    Bai, J. Xu, B.; Guzman, F. G.; Xing, K.; Gong, Y.; Hou, Y.; Wang, T.

    2015-12-28

    We demonstrate semipolar InGaN single-quantum-well light emitting diodes (LEDs) in the green, yellow-green, yellow and amber spectral region. The LEDs are grown on our overgrown semipolar (11-22) GaN on micro-rod array templates, which are fabricated on (11-22) GaN grown on m-plane sapphire. Electroluminescence measurements on the (11-22) green LED show a reduced blue-shift in the emission wavelength with increasing driving current, compared to a reference commercial c-plane LED. The blue-shifts for the yellow-green and yellow LEDs are also significantly reduced. All these suggest an effective suppression in quantum confined Stark effect in our (11-22) LEDs. On-wafer measurements yield a linear increase in the light output with the current, and external quantum efficiency demonstrates a significant improvement in the efficiency-droop compared to a commercial c-plane LED. Electro-luminescence polarization measurements show a polarization ratio of about 25% in our semipolar LEDs.

  6. Brine migration test for Asse Mine, Federal Republic of Germany: final test plan

    SciTech Connect

    Not Available

    1983-07-01

    The United States and the Federal Republic of Germany (FRG) will conduct a brine migration test in the Asse Salt Mine in the FRG as part of the US/FRG Cooperative Radioactive Waste Management Agreement. Two sets of two tests each will be conducted to study both liquid inclusion migration and vapor migration in the two salt types chosen for the experiments: (1) pure salt, for its characteristics similar to the salt that might occur in potential US repositories, and (2) transitional salt, for its similarity to the salt that might occur in potential repositories in Germany.

  7. Comparing Germany's and California's Interconnection Processes for PV Systems (White Paper)

    SciTech Connect

    Tweedie, A.; Doris, E.

    2011-07-01

    Establishing interconnection to the grid is a recognized barrier to the deployment of distributed energy generation. This report compares interconnection processes for photovoltaic projects in California and Germany. This report summarizes the steps of the interconnection process for developers and utilities, the average length of time utilities take to process applications, and paperwork required of project developers. Based on a review of the available literature, this report finds that while the interconnection procedures and timelines are similar in California and Germany, differences in the legal and regulatory frameworks are substantial.

  8. Better Catalysts through Microscopy: Mesoscale M1/M2 Intergrowth in Molybdenum–Vanadium Based Complex Oxide Catalysts for Propane Ammoxidation

    SciTech Connect

    He, Qian; Woo, Jungwon; Belianinov, Alexei; Guliants, Vadim V.; Borisevich, Albina Y.

    2015-03-06

    Catalysis research has transformed from the predominantly empirical field to one where it is possible to control the catalytic properties via characterization and modification of the atomic-scale active centers. Many phenomena in catalysis, such as synergistic effect, however, transcend the atomic scale and also require the knowledge and control of the mesoscale structure of the specimen to harness. Our paper, we use our discovery of atomic-scale epitaxial interfaces in molybdenum vanadium based complex oxide catalysts systems (i.e., MoVMO, M = Ta, Te, Sb, Nb, etc.) to achieve control of the mesoscale structure of this complex mixture of very different active phases. We can now achieve true epitaxial intergrowth between the catalytically critical M1 and M2 phases in the system that are hypothesized to have synergistic interactions, and demonstrate that the resulting catalyst has improved selectivity in the initial studies. Finally, we highlight the crucial role atomic scale characterization and mesoscale structure control play in uncovering the complex underpinnings of the synergistic effect in catalysis.

  9. Better Catalysts through Microscopy: Mesoscale M1/M2 Intergrowth in Molybdenum–Vanadium Based Complex Oxide Catalysts for Propane Ammoxidation

    DOE PAGES [OSTI]

    He, Qian; Woo, Jungwon; Belianinov, Alexei; Guliants, Vadim V.; Borisevich, Albina Y.

    2015-03-06

    Catalysis research has transformed from the predominantly empirical field to one where it is possible to control the catalytic properties via characterization and modification of the atomic-scale active centers. Many phenomena in catalysis, such as synergistic effect, however, transcend the atomic scale and also require the knowledge and control of the mesoscale structure of the specimen to harness. Our paper, we use our discovery of atomic-scale epitaxial interfaces in molybdenum vanadium based complex oxide catalysts systems (i.e., MoVMO, M = Ta, Te, Sb, Nb, etc.) to achieve control of the mesoscale structure of this complex mixture of very different activemore » phases. We can now achieve true epitaxial intergrowth between the catalytically critical M1 and M2 phases in the system that are hypothesized to have synergistic interactions, and demonstrate that the resulting catalyst has improved selectivity in the initial studies. Finally, we highlight the crucial role atomic scale characterization and mesoscale structure control play in uncovering the complex underpinnings of the synergistic effect in catalysis.« less

  10. Adsorption of propane, isopropyl, and hydrogen on cluster models of the M1 phase of Mo-V-Te-Nb-O mixed metal oxide catalyst

    SciTech Connect

    Govindasamy, Agalya; Muthukumar, Kaliappan; Yu, Junjun; Xu, Ye; Guliants, Vadim V.

    2010-01-01

    The Mo-V-Te-Nb-O mixed metal oxide catalyst possessing the M1 phase structure is uniquely capable of directly converting propane into acrylonitrile. However, the mechanism of this complex eight-electron transformation, which includes a series of oxidative H-abstraction and N-insertion steps, remains poorly understood. We have conducted a density functional theory study of cluster models of the proposed active and selective site for propane ammoxidation, including the adsorption of propane, isopropyl (CH{sub 3}CHCH{sub 3}), and H which are involved in the first step of this transformation, that is, the methylene C-H bond scission in propane, on these active site models. Among the surface oxygen species, the telluryl oxo (Te=O) is found to be the most nucleophilic. Whereas the adsorption of propane is weak regardless of the MO{sub x} species involved, isopropyl and H adsorption exhibits strong preference in the order of Te=O > V=O > bridging oxygens > empty Mo apical site, suggesting the importance of TeO{sub x} species for H abstraction. The adsorption energies of isopropyl and H and consequently the reaction energy of the initial dehydrogenation of propane are strongly dependent on the number of ab planes included in the cluster, which points to the need to employ multilayer cluster models to correctly capture the energetics of surface chemistry on this mixed metal oxide catalyst.

  11. DOE Signs Notice to Prepare Environmental Assessment on Proposed Project with Germany

    Office of Energy Efficiency and Renewable Energy (EERE)

    WASHINGTON, D.C. – The Energy Department recently signed a notice of intent to prepare an environmental assessment to analyze the potential environmental impacts from a proposed project to accept used nuclear fuel from the Federal Republic of Germany at DOE’s Savannah River Site (SRS) for processing and disposition.

  12. Proceedings of Workshop on Uranium Production Environmental Restoration: An exchange between the United States and Germany

    SciTech Connect

    Not Available

    1993-12-31

    Scientists, engineers, elected officials, and industry regulators from the United, States and Germany met in Albuquerque, New Mexico, August 16--20, 1993, in the first joint international workshop to discuss uranium tailings remediation. Entitled ``Workshop on Uranium Production Environmental Restoration: An Exchange between the US and Germany,`` the meeting was hosted by the US Department of Energy`s (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. The goal of the workshop was to further understanding and communication on the uranium tailings cleanup projects in the US and Germany. Many communities around the world are faced with an environmental legacy -- enormous quantities of hazardous and low-level radioactive materials from the production of uranium used for energy and nuclear weapons. In 1978, the US Congress passed the Uranium Mill Tailings Radiation Control Act. Title I of the law established a program to assess the tailings at inactive uranium processing sites and provide a means for joint federal and state funding of the cleanup efforts at sites where all or substantially all of the uranium was produced for sale to a federal agency. The UMTRA Project is responsible for the cleanup of 24 sites in 10 states. Germany is facing nearly identical uranium cleanup problems and has established a cleanup project. At the workshop, participants had an opportunity to interact with a broad cross section of the environmental restoration and waste disposal community, discuss common concerns and problems, and develop a broader understanding of the issues. Abstracts are catalogued individually for the data base.

  13. Implementing the Espoo Convention in transboundary EIA between Germany and Poland

    SciTech Connect

    Albrecht, Eike

    2008-08-15

    Poland and Germany have a long common border which leads to the necessity to cooperate and consult each other in the case of large-scale projects or infrastructure measures likely to cause negative transboundary effects on the environment. There are already binding provisions for transboundary EIA. In the area of the UN Economic Commission for Europe (UNECE), transboundary EIA is intended to be legally binding for the Member States by the Espoo Convention which was ratified by Germany 8.8.2002 and by Poland 12.6.1997. Due to corresponding directives, the same is applicable in the context of the European Union. In German legislation, this issue is regulated by Art. 8 of the Federal EIA Act in regard to transboundary participation of administration and by Art. 9a in respect of transboundary public participation. However, these EIA regulations on transboundary participation do not surpass a certain detail level, as they have to be applied between Germany and all neighbouring states. Therefore both countries decided to agree on more detailed provisions in particular regarding procedural questions. During the 12th German-Polish Environmental Council, Germany and Poland reached an agreement on 11.4.2006 in Neuhardenberg/Brandenburg an agreement upon the implementation of the Espoo Convention, the so called Neuhardenberg Agreement. This article assesses the agreement under consideration of already existing law and discusses major improvements and problems.

  14. Donor impurity states and related terahertz range nonlinear optical response in GaN cylindrical quantum wires: Effects of external electric and magnetic fields

    SciTech Connect

    Correa, J. D.; Mora-Ramos, M. E.; Duque, C. A.

    2014-06-07

    We report a study on the optical absorption coefficient associated to hydrogenic impurity interstate transitions in zinc-blende GaN quantum wires of cylindrical shape taking into account the effects of externally applied static electric and magnetic fields. The electron states emerge within the effective mass approximation, via the exact diagonalization of the donor-impurity Hamiltonian with parabolic confinement and external field effects. The nonlinear optical absorption is calculated using a recently derived expression for the dielectric susceptibility, obtained via a nonperturbative solution of the density-matrix Bloch equation. Our results show that this treatment eliminates not only the intensity-dependent bleaching effect but also the change in sign of the nonlinear contribution due to the combined effect of asymmetric impurity location and the applied electric field.

  15. Influence of stress on optical transitions in GaN nanorods containing a single InGaN/GaN quantum disk

    SciTech Connect

    Zhuang, Y. D.; Shields, P. A.; Allsopp, D. W. E.; Bruckbauer, J.; Edwards, P. R.; Martin, R. W.

    2014-11-07

    Cathodoluminescence (CL) hyperspectral imaging has been performed on GaN nanorods containing a single InGaN quantum disk (SQD) with controlled variations in excitation conditions. Two different nanorod diameters (200 and 280 nm) have been considered. Systematic changes in the CL spectra from the SQD were observed as the accelerating voltage of the electron beam and its position of incidence are varied. It is shown that the dominant optical transition in the SQD varies across the nanorod as a result of interplay between the contributions of the deformation potential and the quantum-confined Stark effect to the transition energy as consequence of radial variation in the pseudomorphic strain.

  16. Panel 1, Towards Sustainable Energy Systems: The Role of Large-Scale Hydrogen Storage in Germany

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Hanno Butsch | Head of International Cooperation NOW GmbH National Organization Hydrogen and Fuel Cell Technology Towards sustainable energy systems - The role of large scale hydrogen storage in Germany May 14th, 2014 | Sacramento Political background for the transition to renewable energies 2 * Climate protection: Global responsibility for the next generation. * Energy security: More independency from fossil fuels. * Securing the economy: Creating new markets and jobs through innovations. Three

  17. An Analysis of Residential PV System Price Differences between the United States and Germany

    Office of Energy Efficiency and Renewable Energy (EERE)

    Residential photovoltaic (PV) systems were twice as expensive in the United States as in Germany (median of $5.29/W vs. $2.59/W) in 2012. This price discrepancy stems primarily from differences in non-hardware or "soft" costs between the two countries, which can only be explained in part by differences in cumulative market size and associated learning. A survey of German PV installers was deployed to collect rough data on PV soft costs in Germany to compare to results of a similar survey of U.S. PV installers. Non-module hardware costs and all analyzed soft costs are lower in Germany, especially for customer acquisition, installation labor, and profit/overhead costs, but also for expenses related to permitting, interconnection, and inspection procedures. Additional costs occur in the United States due to state and local sales taxes, smaller average system sizes, and longer project development times. To reduce the identified additional costs of residential PV systems, the United States could introduce policies that enable a robust and lasting market while minimizing market fragmentation.

  18. Thermoelectric properties of the 3C, 2H, 4H, and 6H polytypes of the wide-band-gap semiconductors SiC, GaN, and ZnO

    SciTech Connect

    Huang, Zheng; Lü, Tie-Yu; Wang, Hui-Qiong; Zheng, Jin-Cheng

    2015-09-15

    We have investigated the thermoelectric properties of the 3C, 2H, 4H, and 6H polytypes of the wide-band-gap(n-type) semiconductors SiC, GaN, and ZnO based on first-principles calculations and Boltzmann transport theory. Our results show that the thermoelectric performance increases from 3C to 6H, 4H, and 2H structures with an increase of hexagonality for SiC. However, for GaN and ZnO, their power factors show a very weak dependence on the polytype. Detailed analysis of the thermoelectric properties with respect to temperature and carrier concentration of 4H-SiC, 2H-GaN, and 2H-ZnO shows that the figure of merit of these three compounds increases with temperature, indicating the promising potential applications of these thermoelectric materials at high temperature. The significant difference of the polytype-dependent thermoelectric properties among SiC, GaN, and ZnO might be related to the competition between covalency and ionicity in these semiconductors. Our calculations may provide a new way to enhance the thermoelectric properties of wide-band-gap semiconductors through atomic structure design, especially hexagonality design for SiC.

  19. The U.S. Army`s environmental compliance assessment in Germany, a case study

    SciTech Connect

    Schlessman, D.C.

    1995-12-01

    The U.S. Army, Europe (USAREUR) in 1995 is initiating the Army-wide program of assessing environmental compliance at each of its installations. The first assessment was done in Germany in January and is the basis of this study. These assessments are the conerstone of USAREUR`s compliance standards: air emissions, drinking and waste water standards, environmental noise, radon, asbestos, underground storage tanks, hazardous material and petroleum management, and pesticides. Also covered are areas of waste management to include solid, hazardous, and medical wastes and special requirements for handling and disposal of polychlorinated bi- & terphenyls. In addition policy and other science areas are checked. These include environmental program management, environmental effects analysis, endangered species and natural resource protection, and historical and cultural resource preservation. The ECAS`s breadth of medias assessed gives a comprehensive look at the environmental posture of an installation. One of the two manuals used in each assessment is based on the Department of Defense (DOD) environmental final governing standards (FGS). Each overseas country that has a substantial DOD long-term presence has a FGS. The FGS is developed by a DOD appointed executive agent. He compared the DOD baseline of environmental standards (based on U.S. law and DOD policy) and the HN`s environmental standards. From this comparison the standard that is most protective of human health and the environment is selected as the FGS. In Germany, the FGS, and thus the ECAS manual are substantially based on the German standards. This is due tot he well developed environmental standards found in Germany. This study provides the first look at the USAREUR ECAS process and the major changes required in a USAREUR community`s environmental compliance posture to meet the German FGS. The January Anbach ECAS is the first time a community in USAREUR was assessed using the fully operational ECAS.

  20. Three-dimensional spectrum mapping of bright emission centers: Investigating the brightness-limiting process in Eu-doped GaN red light emitting diodes

    SciTech Connect

    Ishii, Masashi; Koizumi, Atsushi; Fujiwara, Yasufumi

    2015-08-24

    A pulse-driven emission-spectroscopy mapping technique is used to investigate the bright emission centers in Eu-doped GaN (GaN:Eu) red light emitting diodes (LED). The LEDs are operated in pulse-driven mode, and the emission spectra are acquired for a range of pulse frequencies. This ensemble of emission spectral data yields a three-dimensional mapping that allows the origin of emission lines to be identified by visual inspection. The identification was achieved even for a weak {sup 5}D{sub 0} → {sup 7}F{sub 3} transition in conventional photoluminescence measurements. A peculiar split is observed in the {sup 5}D{sub 0} → {sup 7}F{sub 3} transition for the bright emission center referred to as OMVPE 8. Despite the unique transition at this emission center, the emission efficiencies for the {sup 5}D{sub 0} → {sup 7}F{sub 3} and {sup 5}D{sub 0} → {sup 7}F{sub 2} transitions were identical. This finding indicates that the excitation of the emission centers, rather than the radiative transitions, is the limiting process that determines the GaN:Eu red LED brightness.

  1. Relaxation and critical strain for maximum In incorporation in AlInGaN on GaN grown by metal organic vapour phase epitaxy

    SciTech Connect

    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.

  2. Greenhouse gas mitigation in a carbon constrained world - the role of CCS in Germany

    SciTech Connect

    Schumacher, Katja; Sands, Ronald D.

    2009-01-05

    In a carbon constrained world, at least four classes of greenhouse gas mitigation options are available: energy efficiency, switching to low or carbon-free energy sources, introduction of carbon dioxide capture and storage along with electric generating technologies, and reductions in emissions of non-CO2 greenhouse gases. The contribution of each option to overall greenhouse gas mitigation varies by cost, scale, and timing. In particular, carbon dioxide capture and storage (CCS) promises to allow for low-emissions fossil-fuel based power generation. This is particularly relevant for Germany, where electricity generation is largely coal-based and, at the same time, ambitious climate targets are in place. Our objective is to provide a balanced analysis of the various classes of greenhouse gas mitigation options with a particular focus on CCS for Germany. We simulate the potential role of advanced fossil fuel based electricity generating technologies with CCS (IGCC, NGCC) as well the potential for retrofit with CCS for existing and currently built fossil plants from the present through 2050. We employ a computable general equilibrium (CGE) economic model as a core model and integrating tool.

  3. Brine migration test report: Asse Salt Mine, Federal Republic of Germany: Technical report

    SciTech Connect

    Coyle, A.J.; Eckert, J.; Kalia, H.

    1987-01-01

    This report presents a summary of Brine Migration Tests which were undertaken at the Asse mine of the Federal Republic of Germany (FRG) under a bilateral US/FRG agreement. This experiment simulates a nuclear waste repository at the 800-m (2624-ft) level of the Asse salt mine in the Federal Republic of Germany. This report describes the Asse salt mine, the test equipment, and the pretest properties of the salt in the mine and in the vicinity of the test area. Also included are selected test data (for the first 28 months of operation) on the following: brine migration rates, thermomechaical behavior of the salt (including room closure, stress reading, and thermal profiles), borehole gas pressures, and borehole gas analyses. In addition to field data, laboratory analyses of pretest salt properties are included in this report. The operational phase of these experiments was completed on October 4, 1985, with the commencement of cooldown and the start of posttest activities. 7 refs., 68 figs., 48 tabs.

  4. Research on long term safety of nuclear waste disposal at the research center Karlsruhe, Germany

    SciTech Connect

    Gompper, Klaus; Bosbach, Dirk; Denecke, Melissa A.; Geckeis, Horst; Kienzler, Bernhard; Klenze, Reinhardt

    2007-07-01

    In Germany the safe disposal of radioactive waste is in the responsibility of the federal government. The R and D performed in the Institute for Nuclear Waste Disposal (INE) at the Research Center Karlsruhe contributes to the German provident research in the field of long-term safety for final disposal of high level heat producing nuclear wastes. INE's research is focused on the actinide elements and long lived fission products since these dominate the radiotoxicity over a long time. The research strategy synergistically combines fundamental science of aquatic radionuclide chemistry with applied investigations of real systems (waste form, host rock, aquifer), studied on laboratory scale and in underground laboratories. Because Germany has not yet selected a site for a high-level waste repository, all host rock formations under discussion in the international community (salt, hard rock, clay/tone) are investigated. Emphasis in long-term safety R and D at INE is on the development of actinide speciation methods and techniques in the trace concentration range. (authors)

  5. M1 Energy | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    either solely or in partnership. Their project scope is focused on small to medium-sized oil, gas and electricity projects. Coordinates: 41.88415, -87.632409 Show Map Loading...

  6. Perspectives of Future R and D on HLW Disposal in Germany

    SciTech Connect

    Steininger, W.J. [Forschungszentrum Karlsruhe GmbH, Project Management Agency Forschungszentrum Karlsruhe (PTKA-WTE), Eggenstein-Leopoldshafen (Germany)

    2008-07-01

    The 5. Energy Research Program of the Federal Government 'Innovation and New Technology' is the general framework for R and D activities in radioactive waste disposal. The Ministry of Economics and Technology (BMWi), the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) and the Ministry of Education and Research (BMBF) apply the Research Program concerning their respective responsibilities and competences. With regard to the Government's obligation to provide repositories for HLW (spent fuel and vitrified HAW) radioactive waste basic and applied R and D is needed in order to make adequate knowledge available to implementers, decision makers and stakeholders in general. Non-site specific R and D projects are funded by BMWi on the basis of its Research Concept. In the first stage (1998 -2001) most R and D issues were focused on R and D activities related to HLW disposal in rock salt. By that time the R and D program had to be revised and some prioritization was demanded due to changes in politics. In the current version (2001 -2006) emphasize was put on non-saline rocks. The current Research Concept of BMWi is presently subjected to a sort of revision, evaluation, and discussion, inter alia, by experts from several German research institutions. This activity is of special importance against the background of streamlining and focusing the research activities to future demands, priorities and perspectives with regard to the salt concept and the option of disposing of HLW in argillaceous media. Because the status of knowledge on disposal in rock salt is well advanced, it is necessary to take stock of the current state-of-the-art. In this framework some key projects are being currently carried out. The results may contribute to future decisions to be made in Germany with respect to HLW disposal. The first project deals with the development of an advanced safety concept for a HLW waste repository in rock salt. The second project (also

  7. Current and anticipated uses of thermal-hydraulic codes in Germany

    SciTech Connect

    Teschendorff, V.; Sommer, F.; Depisch, F.

    1997-07-01

    In Germany, one third of the electrical power is generated by nuclear plants. ATHLET and S-RELAP5 are successfully applied for safety analyses of the existing PWR and BWR reactors and possible future reactors, e.g. EPR. Continuous development and assessment of thermal-hydraulic codes are necessary in order to meet present and future needs of licensing organizations, utilities, and vendors. Desired improvements include thermal-hydraulic models, multi-dimensional simulation, computational speed, interfaces to coupled codes, and code architecture. Real-time capability will be essential for application in full-scope simulators. Comprehensive code validation and quantification of uncertainties are prerequisites for future best-estimate analyses.

  8. Regulatory Control of Sealed Sources in Germany including Regulations Regarding Spent and Disused Sources - 13176

    SciTech Connect

    Dollan, Ralph; Haeusler, Uwe; Czarwinski, Renate

    2013-07-01

    Effective regulatory control is essential to ensure the safe and secure use of radioactive material and the appropriate management of radioactive waste. To ensure a sustainable control of high radioactive sources, the European Commission published the Council Directive 2003/122/EURATOM on the control of high-activity sealed radioactive sources and orphan sources, which had to be transferred into national legislation by all member states of the European Union. Major requirement of the Directive is a system to ensure traceability of high-activity sealed sources from 'cradle to grave' as well as the provision to take back disused sources by the supplier or manufacturer. With the Act on high-activity sealed radioactive sources Germany implemented the requirements of the Directive 2003/122/EURATOM and established a national registry of high-activity sealed sources in 2006. Currently, about 27.000 high-activity sealed sources are recorded in this national registry. (authors)

  9. Assessing climate impacts of planning policies-An estimation for the urban region of Leipzig (Germany)

    SciTech Connect

    Schwarz, Nina Bauer, Annette Haase, Dagmar

    2011-03-15

    Local climate regulation by urban green areas is an important urban ecosystem service, as it reduces the extent of the urban heat island and therefore enhances quality of life. Local and regional planning policies can control land use changes in an urban region, which in turn alter local climate regulation. Thus, this paper describes a method for estimating the impacts of current land uses as well as local and regional planning policies on local climate regulation, using evapotranspiration and land surface emissivity as indicators. This method can be used by practitioners to evaluate their policies. An application of this method is demonstrated for the case study Leipzig (Germany). Results for six selected planning policies in Leipzig indicate their distinct impacts on climate regulation and especially the role of their spatial extent. The proposed method was found to easily produce a qualitative assessment of impacts of planning policies on climate regulation.

  10. Occupational obstructive airway diseases in Germany: Frequency and causes in an international comparison

    SciTech Connect

    Latza, U.; Baur, X.

    2005-08-01

    Occupational inhalative exposures contribute to a significant proportion of obstructive airway diseases (OAD), namely chronic obstructive pulmonary disease (COPD) and asthma. The number of occupational OAD in the German industrial sector for the year 2003 are presented. Other analyses of surveillance data were retrieved from Medline. Most confirmed reports of OAD are cases of sensitizer induced occupational asthma (625 confirmed cases) followed by COPD in coal miners (414 cases), irritant induced occupational asthma (156 cases), and isocyanate asthma (54 cases). Main causes of occupational asthma in Germany comprise flour/flour constituents (35.9%), food/feed dust (9.0%), and isocyanates (6.5%). Flour and grain dust is a frequent cause of occupational asthma in most European countries and South Africa. Isocyanates are still a problem worldwide. Although wide differences in the estimated incidences between countries exist due to deficits in the coverage of occupational OAD, the high numbers necessitate improvement of preventive measures.

  11. U.S. Department of Energy, National Energy Technology Laboratory Solid-State Lighting Core Technologies Light Emitting Diodes on Semipolar Bulk GaN Substrate with IQE > 80% at 150 A/cm2 and 100 0C

    SciTech Connect

    Chakraborty, Arpan; David, Aurelien; Grundmann, Michael; Tyagi, Anurag; Craven, Michael; Hurni, Christophe; Cich, Michael

    2015-03-31

    GaN is a crucial material for light-emitting diodes (LEDs) emitting in the violet-to-green range. Despite its good performance, it still suffers from significant technical limitations. In particular, the efficiency of GaN-based LEDs decreases at high current (“current droop”) and high temperature (“temperature droop”). This is problematic in some lighting applications, where a high-power operation is required. This program studied the use of particular substrates to improve the efficiency of GaN-based LEDs: bulk semipolar (SP) GaN substrates. These substrates possess a very high material quality, and physical properties which are distinctly different from legacy substrates currently used in the LED industry. The program focused on the development of accurate metrology to quantify the performance of GaN-based LEDs, and on improvement to LED quality and design on SP substrates. Through a thorough optimization process, we demonstrated violet LEDs with very high internal quantum efficiency, exceeding 85% at high temperature and high current. We also investigated longer-wavelength blue emitters, but found that the limited strain budget was a key limitation.

  12. Disposing of High-Level Radioactive Waste in Germany - A Note from the Licensing Authority - 12530

    SciTech Connect

    Pick, Thomas Stefan; Bluth, Joachim; Lauenstein, Christof; Markhoefer, Joerg

    2012-07-01

    Following the national German consensus on the termination of utilisation of nuclear energy in the summer of 2011, the Federal and Laender Governments have declared their intention to work together on a national consensus on the disposal of radioactive waste as well. Projected in the early 1970's the Federal Government had started exploring the possibility to establish a repository for HLW at the Gorleben site in 1977. However, there is still no repository available in Germany today. The delay results mainly from the national conflict over the suitability of the designated Gorleben site, considerably disrupting German society along the crevice that runs between supporters and opponents of nuclear energy. The Gorleben salt dome is situated in Lower Saxony, the German state that also hosts the infamous Asse mine repository for LLW and ILW and the Konrad repository project designated to receive LLW and ILW as well. With the fourth German project, the Morsleben L/ILW repository only 20 km away across the state border, the state of Lower Saxony carries the main load for the disposal of radioactive waste in Germany. After more than 25 years of exploration and a 10 year moratorium the Gorleben project has now reached a cross-road. Current plans for setting up a new site selection procedure in Germany call for the selection and exploration of up to four alternative sites, depending only on suitable geology. In the meantime the discussion is still open on whether the Gorleben project should be terminated in order to pacify the societal conflict or being kept in the selection process on account of its promising geology. The Lower Saxony Ministry for Environment and Climate Protection proposes to follow a twelve-step-program for finding the appropriate site, including the Gorleben site in the process. With its long history of exploration the site is the benchmark that alternative sites will have to compare with. Following the national consensus of 2011 on the termination of

  13. Comparison of Biological Effectiveness of Carbon-Ion Beams in Japan and Germany

    SciTech Connect

    Uzawa, Akiko; Ando, Koichi Koike, Sachiko; Furusawa, Yoshiya; Matsumoto, Yoshitaka; Takai, Nobuhiko; Hirayama, Ryoichi; Watanabe, Masahiko; Scholz, Michael; Elsaesser, Thilo; Peschke, Peter

    2009-04-01

    Purpose: To compare the biological effectiveness of 290 MeV/amu carbon-ion beams in Chiba, Japan and in Darmstadt, Germany, given that different methods for beam delivery are used for each. Methods and Materials: Murine small intestine and human salivary gland tumor (HSG) cells exponentially growing in vitro were irradiated with 6-cm width of spread-out Bragg peaks (SOBPs) adjusted to achieve nearly identical beam depth-dose profiles at the Heavy-Ion Medical Accelerator in Chiba, and the SchwerIonen Synchrotron in Darmstadt. Cell kill efficiencies of carbon ions were measured by colony formation for HSG cells and jejunum crypts survival in mice. Cobalt-60 {gamma} rays were used as the reference radiation. Isoeffective doses at given survivals were used for relative biological effectiveness (RBE) calculations and interinstitutional comparisons. Results: Isoeffective D{sub 10} doses (mean {+-} standard deviation) of HSG cells ranged from 2.37 {+-} 0.14 Gy to 3.47 {+-} 0.19 Gy for Chiba and from 2.31 {+-} 0.11 Gy to 3.66 {+-} 0.17 Gy for Darmstadt. Isoeffective D{sub 10} doses of gut crypts after single doses ranged from 8.25 {+-} 0.17 Gy to 10.32 {+-} 0.14 Gy for Chiba and from 8.27 {+-} 0.10 Gy to 10.27 {+-} 0.27 Gy for Darmstadt, whereas isoeffective D{sub 30} doses after three fractionated doses were 9.89 {+-} 0.17 Gy through 13.70 {+-} 0.54 Gy and 10.14 {+-} 0.20 Gy through 13.30 {+-} 0.41 Gy for Chiba and Darmstadt, respectively. Overall difference of RBE between the two facilities was 0-5% or 3-7% for gut crypt survival or HSG cell kill, respectively. Conclusion: The carbon-ion beams at the National Institute of Radiological Sciences in Chiba, Japan and the Gesellschaft fuer Schwerionenforschung in Darmstadt, Germany are biologically identical after single and daily fractionated irradiation.

  14. Poole-Frenkel effect on electrical characterization of Al-doped ZnO films deposited on p-type GaN

    SciTech Connect

    Huang, Bohr-Ran; Liao, Chung-Chi; Ke, Wen-Cheng Chang, Yuan-Ching; Huang, Hao-Ping; Chen, Nai-Chuan

    2014-03-21

    This paper presents the electrical properties of Al-doped ZnO (AZO) films directly grown on two types of p-type GaN thin films. The low-pressure p-GaN thin films (LP-p-GaN) exhibited structural properties of high-density edge-type threading dislocations (TDs) and compensated defects (i.e., nitrogen vacancy). Compared with high-pressure p-GaN thin films (HP-p-GaN), X-ray photoemission spectroscopy of Ga 3d core levels indicated that the surface Fermi-level shifted toward the higher binding-energy side by approximately 0.7 eV. The high-density edge-type TDs and compensated defects enabled surface Fermi-level shifting above the intrinsic Fermi-level, causing the surface of LP-p-GaN thin films to invert to n-type semiconductor. A highly nonlinear increase in leakage current regarding reverse-bias voltage was observed for AZO/LP-p-GaN. The theoretical fits for the reverse-bias voltage region indicated that the field-assisted thermal ionization of carriers from defect associated traps, which is known as the Poole-Frenkel effect, dominated the I-V behavior of AZO/LP-p-GaN. The fitting result estimated the trap energy level at 0.62 eV below the conduction band edge. In addition, the optical band gap increased from 3.50 eV for as-deposited AZO films to 3.62 eV for 300 °C annealed AZO films because of the increased carrier concentration. The increasing Fermi-level of the 300 °C annealed AZO films enabled the carrier transport to move across the interface into the LP-p-GaN thin films without any thermal activated energy. Thus, the Ohmic behavior of AZO contact can be achieved directly on the low-pressure p-GaN films at room temperature.

  15. Strategic environmental assessment (SEA) for wind energy planning: Lessons from the United Kingdom and Germany

    SciTech Connect

    Phylip-Jones, J. Fischer, T.B.

    2015-01-15

    This paper reports on SEA applied in the wind energy sector in the UK and Germany. Based on a review of 18 SEAs, it is found that the quality of SEA documentation is variable, with over a third of them being deemed unsatisfactory. Furthermore, SEA processes are conducted to varying degrees of effectiveness, with scoping a strength but impact prediction and mitigation weaknesses. Generally speaking, the influence of SEA on German wind energy plan making was found to be low and the influence of SEA on UK plans deemed to be moderate. The German plans had a low influence mainly because of a perceived high environmental performance of the underlying plans in the first instance. Substantive outcomes of SEA are not always clear and the influence of SEA on decision making is said to be limited in many cases. Finally, a lack of effective tiering between SEA and project level EIA is also observed. In addition, our findings echo some of the weaknesses of SEA practice found in previous studies of SEA effectiveness, including poor impact prediction and significance sections and a lack of detailed monitoring programmes for post plan implementation.

  16. Underground geologic evaluation of the Grossschloppen vein-uranium deposit, West Germany

    SciTech Connect

    Moore, S.C.; Erickson, A.J.; Kolb, S.G.; Maclean, C.J.

    1983-10-01

    The Grossschloppen vein-uranium deposit, Bavaria, West Germany, was examined utilizing underground workings during 1980-82 by Esso Er/ZETA/ GMbH, an affiliate of Exxon Minerals Company (EMC). Geologic evaluation entailed dense drilling of a portion of the deposit from workings constructed specifically for the program. Discovered in 1977, the deposit was initially explored by surface diamond drillholes which allowed definition of a 30-60 m wide vein system discontinuously mineralized along a 1000 m strike length and to at least a 450 m depth. The underground program was conceived as a cost effective procedure to answer questions on vein correlation, grade continuity and variability. A 1200 m decline allowed access for detailed sampling of approximately 10% of the known area of mineralization. Fanned drillholes, logged by gamma probe, were spaced to provide intersections of veins at 10 to 20 m intervals. Six cross cuts also penetrate the pitchblende and uranophane mineralization which occurs in 0.1 to 2.5 m thick quartz veins. Detailed cross-sections and level plans were constructed for resource estimates of the intensively studied portion of the vein system. The program resulted in the discovery of local, high grade areas and an average grade in the evaluated area nearly double that expected from surface drilling.

  17. Multi-criteria assessment of socio-environmental aspects in shrinking cities. Experiences from eastern Germany

    SciTech Connect

    Schetke, Sophie Haase, Dagmar

    2008-10-15

    Demographic change and economic decline produce modified urban land use pattern and densities. Compared to the beginning of the 90s after the German reunification, nowadays massive housing and commercial vacancies followed by demolition and perforation come to pass in many cities of the former GDR. In consequence, a considerable surplus of urban brownfields has been created. Furthermore, the decline in the urban fabric affects social infrastructure and urban greenery of local neighbourhoods. Here, urban planning enters into 'uncharted territory' since it needs to assess the socio-environmental impact of shrinkage. In order to carry out such an evaluation quantitatively, a multi-criteria assessment scheme (MCA) was developed and applied. Firstly, we identified infrastructure and land use changes related to vacancy and demolition. Secondly, demolition scenarios for the coming 20 years were applied in order to give an idea for a long-term monitoring approach at the local district level. A multi-criteria indicator matrix quantifies the socio-environmental impact on both urban greenery and residents. Using it, we set demolition scenarios against urban 'quality of life' targets. Empirical evidence comes from Leipzig, in eastern Germany, a representative case study for urban shrinkage processes. The results show that shrinkage implies socio-environmental changes of residential livelihoods, however, does not simply increase or decrease the overall urban quality of life. The integrated assessment of all indicators identifies environmental and social opportunities, as well as the challenges a shrinking city is faced with.

  18. The evolution of the break preclusion concept for nuclear power plants in Germany

    SciTech Connect

    Schulz, H.

    1997-04-01

    In the updating of the Guidelines for PWR`s of the {open_quotes}Reaktor-Sicherheitskommission{close_quotes} (RSK) in 1981 the requirements on the design have been changed with respect to the postulated leaks and breaks in the primary pressure boundary. The major change was a revision in the requirements for pipe whip protection. As a logical consequence of the {open_quotes}concept of basic safety{close_quotes} a guillotine type break or any other break type resulting in a large opening is not postulated any longer for the calculation of reaction and jet forces. As an upper limit for a leak an area of 0, 1 A (A = open cross section of the pipe) is postulated. This decision was based on a general assessment of the present PWR system design in Germany. Since then a number of piping systems have been requalified in the older nuclear power plants to comply with the break preclusion concept. Also a number of extensions of the concept have been developed to cover also leak-assumptions for branch pipes. Furthermore due considerations have been given to other aspects which could contribute to a leak development in the primary circuit, like vessel penetrations, manhole covers, flanges, etc. Now the break preclusion concept originally applied to the main piping has been developed into an integrated concept for the whole pressure boundary within the containment and will be applied also in the periodic safety review of present nuclear power plants.

  19. Sedimentology and diagenesis of the Zechstein Ca2 carbonate, Late Permian, northwest Germany

    SciTech Connect

    Strohmenger, C.; Rockenbauch, K. ); Love, K.M.; Mitchell, J.C. )

    1993-09-01

    Carbonates of the second Zechstein cycle, the Stassfurt Carbonate (Ca2), constitute north Germany's most prolific carbonate gas play. The underlying Werra Anhydrite (A1) of the first Zechstein cycle and the overlying Basal Anhydrite (A2) of the second Zechstein cycle enclosed the reservoir. An erosional sequence boundary present at the top of the A1 sulfate platform separates the A1 from the overlying Ca2 carbonate platform. Ca2 thickness ranges from 30 to 80 m on the platform, 40 to 250 m on the slope, and 10 to 40 m in the basin. Following flooding of the underlying A1 sulfate platform (Ca2 maximum flooding), Ca2 shallow-water carbonates prograded basinward. Platform, upper slope, middle slope, and lower slope facies are recognized and are subdivided into 27 subfacies. Systematic trends in facies distribution are apparent on depositional dip-oriented well log cross sections. Trends in vertical succession of subfacies types, along with the good correlation between Ca2 facies and A1 thickness, enable mapping of the updip and downdip limits of the facies. Diagenesis is important in determining Ca2 reservoir quality. Reservoir rock is typically fair to good where it is dolomite. Early calcitization (dedolomitization) of the Ca2 yields poor to non-reservoir rocks. Although calcitization in general increases basinward, lateral prediction of mineralogy within individual Ca2 facies is difficult. A multivariate statistical investigation has been initiated to determine parameters, which are important in predicting trends in calcite distribution.

  20. Relation between facies, diagenesis, and reservoir quality of Rotliegende reservoirs in north Germany

    SciTech Connect

    David, F.; Gast, R.; Kraft, T. (BEB Erdgas Erdol GmbH, Hannover (Germany))

    1993-09-01

    In north Germany, the majority of Rotliegende gas fields is confined to an approximately 50 km-wide east-west-orientated belt, which is situated on the gently north-dipping flank of the southern Permian basin. Approximately 400 billion m[sup 3] of natural gas has been found in Rotliegende reservoir sandstones with average porosities of depths ranging from 3500 to 5000 m. Rotliegende deposition was controlled by the Autunian paleo-relief, and arid climate and cyclic transgressions of the desert lake. In general, wadis and large dunefields occur in the hinterland, sebkhas with small isolate dunes and shorelines define the coastal area, and a desert lake occurs to the north. The sandstones deposited in large dunefields contain only minor amounts of illite, anhydrite, and calcite and form good reservoirs. In contrast, the small dunes formed in the sebkha areas were affected by fluctuations of the desert lake groundwaters, causing the infiltration of detrital clay and precipitation of gypsum and calcite. These cements were transformed to illite, anhydrite, and calcite-II during later diagenesis, leading to a significant reduction of the reservoir quality. The best reservoirs occur in the shoreline sandstones because porosity and permeability were preserved by early magnesium-chlorite diagenesis. Since facies controls diagenesis and consequently reservoir quality, mapping of facies also indicates the distribution of reservoir and nonreservoir rocks. This information is used to identify play area and to interpret and calibrate three-dimensional seismic data.

  1. Predicting reservoir facies distribution using high resolution forward stratigraphic modeling (upper Permian Zechstein 2 carbonate, North Germany)

    SciTech Connect

    Leyrer, K.; Strohmenger, C.; Rockenbauch, K.

    1995-08-01

    To improve the prediction of facies within the Upper Permian Zechstein 2 Carbonate (Ca2), high resolution forward stratigraphic modeling was performed. The results show differences in the sedimentary history of various parts of the Southern Permian Basin, permitting a better prediction of reservoir facies distribution. The Zechstein 2 Carbonate contains North Germany`s largest hydrocarbon accumulation. The reservoir overlies the anhydrites of the first Zechstein cycle (Werra Anhydrite, or A1) and is sealed by the anhydrites of the second Zechstein cycle (Basal Anhydrite, or A2). The Ca2 can be subdivided into platform, upper slope, middle slope, lower slope, and basina1 facies with a total of 26 subfacies types. It comprises the transgressive and highstand systems tract, of the third Zechstein sequence (ZS3) and the lowstand systems tract of the fourth Zechstein sequence (ZS4). Furthermore the Ca2 can be subdivided into seven parasequences indicating high-order fluctuations. Although the Ca2 in both Northwest and Northeast Germany share this geological framework, many differences concerning reservoir distribution exist between the two areas. A general stratigraphic, simulation program (PHIL{sup TM} 1.5) was used for two-dimensional modeling of the Ca2 throughout North Germany. Using well data along with published data and modifying the sedimentation-governing factors, it was possible to simulate the current sequence stratigraphic and facies model. Sedimentation during Ca2-time can be characterized as a highly complex system; thus, only slight variations of the input data result in vastly different facies and stratigraphic patterns. This sensitivity offers the possibility to test depositional models and to estimate the relative influences of the sediment-controlling parameters during Ca2-time in different paleotopographic settings.

  2. Wind Technology, Cost, and Performance Trends in Denmark, Germany, Ireland, Norway, the European Union, and the United States: 2007 - 2012; NREL (National Renewable Energy Laboratory)

    SciTech Connect

    Hand, Maureen

    2015-06-15

    This presentation provides a summary of IEA Wind Task 26 report on Wind Technology, Cost, and Performance Trends in Denmark, Germany, Ireland, Norway, the European Union, and the United States: 2007-2012

  3. Heavy-metal contamination on training ranges at the Grafenwoehr Training Area, Germany

    SciTech Connect

    Zellmer, S.D.; Schneider, J.F.

    1993-05-01

    Large quantities of lead and other heavy metals are deposited in the environment of weapons ranges during training exercises. This study was conducted to determine the type, degree, and extent of heavy-metal contamination on selected handgun, rifle, and hand-grenade ranges at Grafenwoehr Training Area, Germany. Soil, vegetation, and surface-water samples were collected and analyzed using the inductively-coupled plasma atomic-emission spectroscopy (ICP-AES) method and the toxic characterization leaching procedure (TCLP). The ICP-AES results show that above-normal levels of lead and copper are in the surface soil at the handgun range, high concentrations of lead and copper are in the berm and soil surface at the rifle range, and elevated levels of cadmium and above-normal concentrations of arsenic, copper, and zinc are present in the surface soil at the hand-grenade range. The TCLP results show that surface soils can be considered hazardous waste because of lead content at the rifle range and because of cadmium concentration at the hand-grenade range. Vegetation at the handgun and rifle ranges has above-normal concentrations of lead. At the hand-grenade range, both vegetation and surface water have high levels of cadmium. A hand-held X-ray fluorescence (XRF) spectrum analyzer was used to measure lead concentrations in soils in a field test of the method. Comparison of XRF readings with ICP-AES results for lead indicate that the accuracy and precision of the hand-held XRF unit must improve before the unit can be used as more than a screening tool. Results of this study show that heavy-metal contamination at all three ranges is limited to the surface soil; heavy metals are not being leached into the soil profile or transported into adjacent areas.

  4. Disposal of LLW and ILW in Germany - Characterisation and Documentation of Waste Packages with Respect to the Change of Requirements

    SciTech Connect

    Bandt, G.; Spicher, G.; Steyer, St.; Brennecke, P.

    2008-07-01

    Since the 1998 termination of LLW and ILW emplacement in the Morsleben repository (ERAM), Germany, the treatment, conditioning and documentation of radioactive waste products and packages have been continued on the basis of the waste acceptance requirements as of 1995, prepared for the Konrad repository near Salzgitter in Lower Saxony, Germany. The resulting waste products and packages are stored in interim storage facilities. Due to the Konrad license issued in 2002 the waste acceptance requirements have to be completed by additional requirements imposed by the licensing authority, e. g. for the declaration of chemical waste package constituents. Therefore, documentation of waste products and packages which are checked by independent experts and are in parts approved by the responsible authority (Office for Radiation Protection, BfS) up to now will have to be checked again for fulfilling the final waste acceptance requirements prior to disposal. In order to simplify these additional checks, databases are used to ensure an easy access to all known facts about the waste packages. A short balance of the existing waste products and packages which are already checked and partly approved by BfS as well as an overview on the established databases ensuring a fast access to the known facts about the conditioning processes is presented. (authors)

  5. HLW Return from France to Germany - 15 Years of Experience in Public Acceptance and Technical Aspects - 12149

    SciTech Connect

    Graf, Wilhelm

    2012-07-01

    Since in 1984 the national reprocessing concept was abandoned the reprocessing abroad was the only existing disposal route until 1994. With the amendment of the Atomic Energy Act in 2001 spent fuel management changed completely since from 1 June 2005 any delivery of spent fuel to reprocessing plants was prohibited and the direct disposal of spent fuel became mandatory. Until 2005 the total amount of spent fuel to be reprocessed abroad added up to 6080 t HM, 5309 t HM thereof in France. The waste generated from reprocessing - alternatively an equivalent amount of radioactive material - has to be returned to the country of origin according to the commercial contracts signed between the German utilities and COGEMA, now AREVA NC, in France and BNFL, now INS in UK. In addition the German and the French government exchanged notes with the obligation of both sides to enable and support the return of reprocessing residues or equivalents to Germany. The return of high active vitrified waste from La Hague to the interim storage facility at Gorleben was demanding from the technical view i. e. the cask design and the transport. Unfortunately the Gorleben area served as a target for nuclear opponents from the first transport in 1996 to the latest one in 2011. The protection against sabotage of the railway lines and mass protests needed highly improved security measures. In France and Germany special working forces and projects have been set up to cope with this extraordinary situation. A complex transport organization was established to involve all parties in line with the German and French requirements during transport. The last transport of vitrified residues from France has been completed successfully so far thus confirming the efficiency of the applied measures. Over 15 years there was and still is worldwide no comparable situation it is still unique. Summing up, the exceptional project handling challenge that resulted from the continuous anti-nuclear civil disobedience in

  6. Zeeman spectroscopy of the internal transition {sup 4}T{sub 1} to {sup 6}A{sub 1} of Fe{sup 3+} ions in wurtzite GaN

    SciTech Connect

    Neuschl, B. Gödecke, M. L.; Thonke, K.; Feneberg, M.

    2015-12-07

    Internal transitions of Fe{sup 3+} ions in wurtzite gallium nitride were analyzed by means of photoluminescence, Zeeman, and transmission spectroscopy in order to investigate the fine structure. Magnetic fields up to 14 T were applied perpendicular or parallel to the crystal c-axis, causing a characteristic splitting pattern of the luminescence related to the transition from the {sup 4}T{sub 1} excited state to the {sup 6}A{sub 1} ground state of Fe{sup 3+}. The complete Hamiltonian matrix is constructed taking into account the crystal field in cubic and trigonal symmetry, spin-orbit interaction, and the influence of external magnetic fields. Numerical solution yields the exact energy level scheme of the excited state {sup 4}G of Fe{sup 3+} ions in GaN, which partly revises assumptions based on a qualitative treatment considering group theory only and invoking the influence of a Jahn-Teller effect. The coincidence of the calculated energy levels with the experimental data verifies the derived fine structure of the 3d metal ion.

  7. Atmospheric Radiation Measurement (ARM) Data from Black Forest Germany for the Convective and Orographically Induced Precipitation Study (COPS)

    DOE Data Explorer

    The primary goal of the ARM Program is to improve the treatment of cloud and radiation physics in global climate models in order to improve the climate simulation capabilities of these models. ARM maintains four major, permanent sites for data collection and deploys the ARM Mobile Facility (AMF) to other sites as determined. In 2007 the AMF operated in the Black Forest region of Germany as part of the Convective and Orographically Induced Precipitation Study (COPS). Scientists studied rainfall resulting from atmospheric uplift (convection) in mountainous terrain, otherwise known as orographic precipitation. This was part of a six -year duration of the German Quantitative Precipitation Forecasting (QPF) Program. COPS was endorsed as a Research and Development Project by the World Weather Research Program. This program was established by the World Meteorological Organization to develop improved and cost-effective forecasting techniques, with an emphasis on high-impact weather. A large collection of data plots based on data streams from specific instruments used at Black Forest are available via a link from ARM's Black Forest site information page. Users will be requested to create a password, but the plots and the data files in the ARM Archive are free for viewing and downloading.

  8. Feasibility/treatability studies for removal of heavy metals from training range soils at the Grafenwoehr Training Area, Germany

    SciTech Connect

    Peters, R.W.

    1995-05-01

    A feasibility/treatability study was performed to investigate the leaching potential of heavy metals (particularly lead) from soils at the Grafenw6hr Training Area (GTA) in Germany. The study included an evaluation of the effectiveness of chelant extraction to remediate the heavy-metal-contarninated soils. Batch shaker tests indicated that ethylenediaminetetraacetic acid (EDTA) (0.01M) was more effective than citric acid (0.01M) at removing cadmium, copper, lead, and zinc. EDTA and citric acid were equally effective in mobilizing chromium and barium from the soil. The batch shaker technique with chelant extraction offers promise as a remediation technique for heavy-metal-contaninated soil at the GTA. Columnar flooding tests conducted as part of the study revealed that deionized water was the least effective leaching solution for mobilization of the heavy metals; the maximum solubilization obtained was 3.72% for cadmium. EDTA (0.05M) achieved the greatest removal of lead (average removal of 17.6%). The difficulty of extraction using deionized water indicates that all of the heavy metals are very tightly bound to the soil; therefore, they are very stable in the GTA soils and do not pose a serious threat to the groundwater system. Columnar flooding probably does not represent a viable remediation technique for in-situ cleanup of heavy-metal-contaminated soils at the GTA.

  9. Environmental effects of fog oil and CS usage at the Combat Maneuver Training Center, Hohenfels, Germany. [2-chlorophenylmethylene

    SciTech Connect

    Brubaker, K.L.; Rosenblatt, D.H.; Snyder, C.T.

    1992-03-01

    In response to environmental concerns at the Combat Maneuver Training Center (CMTC), Hohenfels, Germany, the US Army 7th Army Training Command commissioned a scientific study by Argonne National Laboratory to investigate specific issues. The study involved three parts: (1) a field study to determine if fog oil and CS (a compound named after its discoverers, B.B. Carson and R.W. Stoughton) were accumulating in the CMTC environment, (2) a screening of selected soil samples for the presence of US Environmental Protection Agency priority pollutants, and (3) a literature review of the health effects of fog oil and CS, as well as a review of training practices at CMTC. No fog oil or fog oil degradation products were detected in any soil, sediment, or vegetation sample collected at CMTC. Trace quantities of one or more priority pollutants were tentatively detected in three of eight soil and sediment samples. However, the priority pollutant concentrations are so low that they pose no environmental or health hazards. No evidence of widespread or significant contamination in the training areas was found. Crucial data needed to fully evaluate both acute and chronic health effects of civilian exposures to CS at CMTC are not available. On the basis of the available literature, long-ten-n health effects in the civilian population near CMTC that could result from the use of fog oil and CS during training activities are believed to be negligible.

  10. EA-1977: Acceptance and Disposition of Used Nuclear Fuel Containing U.S.-Origin Highly Enriched Uranium from the Federal Republic of Germany

    Energy.gov [DOE]

    This environmental assessment (EA) will evaluate the potential environmental impacts of a DOE proposal to accept used nuclear fuel from the Federal Republic of Germany at DOEs Savannah River Site (SRS) for processing and disposition. This used nuclear fuel is composed of kernels containing thorium and U.S.-origin highly enriched uranium (HEU) embedded in small graphite spheres that were irradiated in nuclear reactors used for research and development purposes.

  11. 2013-02-26 11.00 Why Are Residential PV Prices in Germany So Much Lower Than in the United States_

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Why Are Residential PV Prices in Germany So Much Lower Than in the United States? Transcript February 26, 2013 Speakers: Galen Barbose, Lawrence Berkeley National Laboratory Joachim Seel, Lawrence Berkeley National Laboratory Courtney Kendall, U.S. Department of Energy Solar Technologies Office [Courtney Kendall - Slide 1]: Good afternoon. My name is Courtney Kendall from the U.S. Department of Energy Solar Technologies Office and I'd like to welcome you to today's webinar titled, "Why Are

  12. EA-1977: Acceptance and Disposition of Spent Nuclear Fuel Containing U.S.-Origin Highly Enriched Uranium from the Federal Republic of Germany

    Energy.gov [DOE]

    This environmental assessment (EA) will evaluate the potential environmental impacts of a DOE proposal to accept spent nuclear fuel from the Federal Republic of Germany at DOE’s Savannah River Site (SRS) for processing and disposition. This spent nuclear fuel is composed of kernels containing thorium and U.S.-origin highly enriched uranium (HEU) embedded in small graphite spheres that were irradiated in nuclear reactors used for research and development purposes.

  13. Made in Germany

    SciTech Connect

    2005-09-01

    This supplement was prepared in collaboration with the Association of German Mining Machine Manufacturers within VDMA to give an overview of German manufacturers' contribution to the coal industry. It has 18 short papers and a VDMA vendor matrix and directory. Papers include details of MAN Takraf's surface mining equipment, hydraulic shovels and excavators from Komatsu, Liebherr and Terex O & K, Siemens motors and electric control technology in trucks, shovels etc., new technology from DBT, IBS and Wirth, and low emission engines and drives from Deutz and DaimlerCrysler. 2 figs.

  14. Best of Germany 2008

    SciTech Connect

    Casteel, K.

    2008-07-01

    This supplement discusses German mining equipment and technology under the following sections: mining experience and machinery export; underground mining technology; surface mining technology; materials handling technology; coal and minerals processing technology; power technology; and automation, specialized components and materials. Manufacturers of the different equipment and their contact details are given. 4 figs.

  15. Best of Germany 2007

    SciTech Connect

    2007-08-15

    This supplement, sponsored by the German Engineering Federation, VDMA, includes a seven page article on the German mining industry, a two-page article on occupational health and safety; a three-page article on collaboration, consulting and finance in the German mining industry; and a 27 page article on German mining technology and its mining. A buyers guide gives details of German companies selling equipment for the mining industry.

  16. IEA Wind Task 26. Wind Technology, Cost, and Performance Trends in Denmark, Germany, Ireland, Norway, the European Union, and the United States: 2007–2012

    SciTech Connect

    Vitina, Aisma; Lüers, Silke; Wallasch, Anna-Kathrin; Berkhout, Volker; Duffy, Aidan; Cleary, Brendan; Husabø, Lief I.; Weir, David E.; Lacal-Arántegui, Roberto; Hand, Maureen; Lantz, Eric; Belyeu, Kathy; Wiser, Ryan H; Bolinger, Mark; Hoen, Ben

    2015-06-01

    The International Energy Agency Implementing Agreement for cooperation in Research, Development, and Deployment of Wind Energy Systems (IEA Wind) Task 26—The Cost of Wind Energy represents an international collaboration dedicated to exploring past, present and future cost of wind energy. This report provides an overview of recent trends in wind plant technology, cost, and performance in those countries that are currently represented by participating organizations in IEA Wind Task 26: Denmark, Germany, Ireland, Norway, and the United States as well as the European Union.

  17. Evaluation of the utilities energy monitoring and control system installed at the US Army, Europe, Pirmasens and 97th Base Support Battalion, Germany

    SciTech Connect

    Broders, M.A.; McConnell, B.W.

    1992-01-01

    Authorized under an interagency agreements between the US Department of Energy and the US Army, evaluation of the utilities energy monitoring and control system (UEMCSs) operating at selected US Army installations in Heidelberg, Goeppingen, Pirmasens, and Baumholder, Germany, is nearing completion. This report specifically presents the results of the evaluation of the UEMCS installed at USAREUR, 21st Theater Army Area Command (TAACOM), Pirmasens and 97th Base Support Battalion, which is operated by the Directorate of Engineering and Housing (DEH) Utilities Division. The Oak Ridge National Laboratory (ORNL) was selected by Headquarters, USAREUR, Facilities Engineering Division, Utilities and Energy Branch in Heidelberg to evaluated the overall effectiveness and energy efficiency of UEMCSs at four US Army installations in Germany. The third of these systems to be evaluated, which is the scope of this report, is the UEMCS installed at Pirmasens. This evaluation relies upon existing data and information and does not involve introducing metering and instrumentation for the purpose of measuring installation energy use. The primary purpose of this evaluation is to take an in-depth look at the overall performance and effectiveness of the UEMCS installed at Pirmasens to see if it is achieving its operational objectives by resulting in energy and cost savings.

  18. AMIE Gan Island Ancillary Disdrometer Field Campaign...

    Office of Scientific and Technical Information (OSTI)

    Ancillary Disdrometer Field Campaign Report M Oue April 2016 CLIMATE RESEARCH FACILITY DISCLAIMER This report was prepared as an account of work sponsored by the U.S. Government. ...

  19. CLIMATE CHANGE FUEL CELL PROGRAM 200 kW - PC25C FUEL CELL POWER PLANT FOR THE ST.-AGNES-HOSPITAL, BOCHOLT, GERMANY

    SciTech Connect

    Dipl.-Ing. Knut Stahl

    2002-01-31

    Since the beginning of the Year 2001, the Saint-Agnes-Hospital in Bocholt, Germany, operates a phosphoric acid fuel cell (PAFC) to provide the base load of electrical power as well as heat in Winter and air conditioning in Summer. The project was made possible by federal funding from the U.S. Department of Energy as well as by a strategic alliance with the local utility company, the Bocholter Energie- und Wasserversorgung GmbH (BEW), and with the gas supplier of BEW, the Thyssengas GmbH. The fuel cell power plant is combined with an absorption chiller. It is highly efficient and has an excellent power to heat ratio. The operation during the first Year went smoothly and nearly free of trouble.

  20. IEA Wind Task 26. Wind Technology, Cost and Performance Trends in Denmark, Germany, Ireland, Norway, the European Union, and the United States. 2007 - 2012

    SciTech Connect

    Vitina, Aisma; Luers, Silke; Wallasch, Anna-Kathrin; Berkhout, Volker; Duffy, Aidan; Cleary, Brendan; Husabo, Leif I.; Weir, David E.; Lacal-Arantegui, Roberto; Hand, M. Maureen; Lantz, Eric; Belyeu, Kathy; Wiser, Ryan; Bolinger, Mark; Hoen, Ben

    2015-06-12

    This report builds from a similar previous analysis (Schwabe et al., 2011) exploring the differences in cost of wind energy in 2008 among countries participating in IEA Wind Task 26 at that time. The levelized cost of energy (LCOE) is a widely recognized metric for understanding how technology, capital investment, operations, and financing impact the life-cycle cost of building and operating a wind plant. Schwabe et al. (2011) apply a spreadsheet-based cash flow model developed by the Energy Research Centre of the Netherlands (ECN) to estimate LCOE. This model is a detailed, discounted cash flow model used to represent the various cost structures in each of the participating countries from the perspective of a financial investor in a domestic wind energy project. This model is used for the present analysis as well, and comparisons are made for those countries who contributed to both reports, Denmark, Germany, and the United States.

  1. Energies and E1, M1, E2, and M2 transition rates for states of the 2s{sup 2}2p{sup 3}, 2s2p{sup 4}, and 2p{sup 5} configurations in nitrogen-like ions between F III and Kr XXX

    SciTech Connect

    Rynkun, P.; Jönsson, P.; Gaigalas, G.; Froese Fischer, C.

    2014-03-15

    Based on relativistic wavefunctions from multiconfiguration Dirac–Hartree–Fock and configuration interaction calculations, E1, M1, E2, and M2 transition rates, weighted oscillator strengths, and lifetimes are evaluated for the states of the (1s{sup 2})2s{sup 2}2p{sup 3},2s2p{sup 4}, and 2p{sup 5} configurations in all nitrogen-like ions between F III and Kr XXX. The wavefunction expansions include valence, core–valence, and core–core correlation effects through single–double multireference expansions to increasing sets of active orbitals. The computed energies agree very well with experimental values, with differences of only 300–600 cm{sup −1} for the majority of the levels and ions in the sequence. Computed transitions rates are in close agreement with available data from MCHF-BP calculations by Tachiev and Froese Fischer [G.I. Tachiev, C. Froese Fischer, A and A 385 (2002) 716].

  2. AMF Deployment, Black Forest, Germany

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    ... This program was established by the World Meteorological Organization to develop improved and cost-effective forecasting techniques, with an emphasis on high-impact weather. As one ...

  3. CHS M | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    CHS M Jump to: navigation, search Name: CHS & M Place: Germany Product: A local investment cooperative in Bosseborn, Germany. References: CHS & M1 This article is a stub. You can...

  4. ARM - Datastreams - twrcam3m

    Office of Scientific and Technical Information (OSTI)

    Atqasuk AK retired ARM Mobile Facility FKB M1 Browse Data Browse Plots Black Forest, Germany retired GRW M1 Browse Data Browse Plots Graciosa Island, Azores, Portugal retired NIM...

  5. Energy conservation and electricity sector liberalization: Case-studies on the development of cogeneration, wind energy and demand-side management in the Netherlands, Denmark, Germany and the United Kingdom

    SciTech Connect

    Slingerland, S.

    1998-07-01

    In this paper, the development of cogeneration, wind energy and demand-side management in the Netherlands, Denmark, Germany and the United Kingdom are compared. It is discussed to what extent these developments are determined by the liberalization process. Three key liberalization variables are identified: unbundling, privatization and introduction of competition. The analysis suggests that unbundling prior to introduction of full competition in generation is particularly successful in stimulating industrial cogeneration; simultaneous introduction of competition and unbundling mainly stimulates non-cogeneration gas-based capacity; and introduction of competition in itself is likely to impede the development of district-heating cogeneration. Furthermore, it is argued that development of wind energy and demand-side management are primarily dependent on the kind of support system set up by policy makers rather than on the liberalization process. Negative impacts of introduction of competition on integrated resource planning and commercial energy services could nevertheless be expected.

  6. Crystal structures of the M1 and M4 muscarinic acetylcholine...

    Office of Scientific and Technical Information (OSTI)

    Authors: Thal, David M. ; Sun, Bingfa ; Feng, Dan ; Nawaratne, Vindhya ; Leach, Katie ; Felder, Christian C. ; Bures, Mark G. ; Evans, David A. ; Weis, William I. ; Bachhawat, ...

  7. Better Catalysts through Microscopy: Nanometer Scale M1/M2 Intergrown...

    Office of Scientific and Technical Information (OSTI)

    In recent decades, catalysis research has transformed from the predominantly empirical ... Many phenomena in catalysis, such as synergistic effect, however, transcend the atomic ...

  8. C:\\MYDOCS\\FBSS-M~1\\HATTIE\\LAYOUT94.TXT

    Energy Information Administration (EIA) (indexed site)

    3. B4G Percent public order and safety PORDP5 52- 54 MISS3CH. 3. B4H Percent out-patient health care HCOUTP5 56- 58 MISS3CH. 3. B4I Percent industrial INDUSP5 60- 62 MISS3CH....

  9. SECTION M EVALUATION FACTORS FOR AWARD TABLE OF CONTENTS M-1...

    National Nuclear Security Administration (NNSA)

    the policies and procedures in Federal Acquisition Regulation (FAR) Part 15 and Department of Energy Acquisition Regulation (DEAR) Part 915. The Government will evaluate ...

  10. SECTION M EVALUATION FACTORS FOR AWARD TABLE OF CONTENTS M-1...

    National Nuclear Security Administration (NNSA)

    the policies and procedures in Federal Acquisition Regulation (FAR) Part 15 and Department of Energy Acquisition Regulation (DEAR) Part 915. A Source Evaluation Board (SEB) will ...

  11. Microsoft Word - Sandia-VT M-1 Summary Report_FINAL.docx

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    ... with an international reputation for ... Jeffords Center for research and policy; the Vermont Advanced Computing Center; ... the results as a journal article to be ...

  12. ARM - Field Campaign - ARM MJO Investigation Experiment on Gan...

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    was designed to test several current hypotheses regarding the mechanisms responsible for MJO (Madden-Julian Oscillation) initiation and propagation in the Indian Ocean area. ...

  13. AMIE Gan Island Ancillary Disdrometer Field Campaign Report ...

    Office of Scientific and Technical Information (OSTI)

    SMART-R C-band radar, and the National Center for Atmospheric Research (NCAR) dual ... Comparing the disdrometer data with 2DVD data, the raindrop size distribution data will be ...

  14. Lu Gan | Center for Bio-Inspired Solar Fuel Production

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Principal Investigators Postdoctoral Fellows Center researchers Graduate Students Undergraduate Students All Bisfuel Center Personnel Barun Das Bhupesh Goyal Jackson Megiatto Lu...

  15. Visit of the Federal President of Germany

    ScienceCinema

    None

    2011-04-25

    Le D.G. H.Schopper a le plaisir de souhaiter la bienvenue au président de la République fédérale allemande, Richard von Weizsäcker (président féderale de 1984-1994). C'est la première visite d'un président allemand dans l'histoire du Cern.

  16. GE Global Research Europe in Munich, Germany

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Smart Ways to Build Smart Things direct write2square The GE Store for Technology is Open for Business be an engineer Women Engineers Urge Young Girl to Pursue Engineering

  17. MOU_DOE_US_Germany.pdf

    Office of Environmental Management (EM)

    MOJAVE MOJAVE DOE-LPO_Project-Posters_CSP_Mojave.pdf (500.73 KB) More Documents & Publications SOLANA TITLE XVII PROGRAM OVERVIEW (October 2016) GENESIS

    MOJAVE MOJAVE MOJAVE MOJAVE MOJAVE MOJAVE MOJAVE MOJAVE MOJAVE MOJAVE MOJAVE MOJAVE MOJAVE MOJAVE MOJAVE PROJECT SUMMARY In September 2011, the Department of Energy issued a $1.2 billion loan guarantee to finance Mojave, a 250-MW parabolic trough concentrating solar power (CSP) plant on previously disturbed agricultural land near Barstow,

  18. Search for 14.4 keV solar axions from M1 transition of Fe-57...

    Office of Scientific and Technical Information (OSTI)

    K. M. ; Huang, H. Z. ; Kadel, R. ; Kazkaz, K. ; Keppel, G. ; Kogler, L. ; Kolomensky, Yu. G. ; Lenz, D. ; Li, Y. L. ; Ligi, C. ; Liu, X. ; Ma, Y. G. ; Maiano, C. ; Maino, M. ;...

  19. Space-and-Time Resolved Spectroscopy of Single GaN Nanowires

    SciTech Connect

    Upadhya, Prashanth C.; Martinez, Julio A.; Li, Qiming; Wang, George T.; Swartzentruber, Brian S.; Taylor, Antoinette J.; Prasankumar, Rohit P.

    2015-07-01

    Gallium nitridenanowires have garnered much attention in recent years due to their attractive optical and electrical properties. An understanding of carrier transport, relaxation, and recombination in these quasi-one-dimensional nanosystems is therefore important in optimizing them for various applications. We present ultrafast optical microscopic measurements on single GaNnanowires. Furthermore, our experiments, performed while varying the light polarization,excitation fluence, and position, give insight into the mechanisms governing carrier dynamics in these nanosystems.

  20. Negative differential resistance in GaN tunneling hot electron transistors

    SciTech Connect

    Yang, Zhichao; Nath, Digbijoy; Rajan, Siddharth

    2014-11-17

    Room temperature negative differential resistance is demonstrated in a unipolar GaN-based tunneling hot electron transistor. Such a device employs tunnel-injected electrons to vary the electron energy and change the fraction of reflected electrons, and shows repeatable negative differential resistance with a peak to valley current ratio of 7.2. The device was stable when biased in the negative resistance regime and tunable by changing collector bias. Good repeatability and double-sweep characteristics at room temperature show the potential of such device for high frequency oscillators based on quasi-ballistic transport.

  1. LEDs on Semipolar Bulk GaN Substrate with IQE > 80% at 150 A...

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    ... program are disseminated to a broader audience at the annual DOE Solid State Lighting R&D Workshops. Communications: Results from this program have been presented in the ...

  2. Growth and Band Offsets of Epitaxial Lanthanide Oxides on GaN...

    Office of Scientific and Technical Information (OSTI)

    Close Cite: Bibtex Format Close 0 pages in this document matching the terms "" Search For Terms: Enter terms in the toolbar above to search the full text of this document for ...

  3. Functional Mn–Mg{sub k} cation complexes in GaN featured by Raman spectroscopy

    SciTech Connect

    Devillers, T. Bonanni, A.; Leite, D. M. G.; Dias da Silva, J. H.

    2013-11-18

    The evolution of the optical branch in the Raman spectra of (Ga,Mn)N:Mg epitaxial layers as a function of the Mn and Mg concentrations, reveals the interplay between the two dopants. We demonstrate that the various Mn-Mg-induced vibrational modes can be understood in the picture of functional Mn–Mg{sub k} complexes formed when substitutional Mn cations are bound to k substitutional Mg through nitrogen atoms, the number of ligands k being driven by the ratio between the Mg and the Mn concentrations.

  4. S3TEC - Thermal Engineering of GaN Semiconductor Devices | Solid...

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    will be presented where the temperature of the devices was measured using Raman Spectroscopy while the mechanical deformation was measured by Scanning Joule Expansion Microscopy. ...

  5. Ultra-short channel GaN high electron mobility transistor-like...

    Office of Scientific and Technical Information (OSTI)

    based on the velocity-field dependence of two-dimensional electron gas (2-DEG) channel accounting for the ballistic electron acceleration and the inter-valley transfer. In...

  6. P-type doping of GaN (Thesis/Dissertation) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Authors: Wong, R.K. Publication Date: 2000-04-10 OSTI Identifier: 764386 Report Number(s): LBNL--45553 R&D Project: 513310; TRN: US0100055 DOE Contract Number: AC03-76SF00098 ...

  7. Hydride vapor phase GaN films with reduced density of residual electrons and deep traps

    SciTech Connect

    Polyakov, A. Y.; Smirnov, N. B.; Govorkov, A. V.; Yugova, T. G.; Cox, H.; Helava, H.; Makarov, Yu.; Usikov, A. S.

    2014-05-14

    Electrical properties and deep electron and hole traps spectra are compared for undoped n-GaN films grown by hydride vapor phase epitaxy (HVPE) in the regular process (standard HVPE samples) and in HVPE process optimized for decreasing the concentration of residual donor impurities (improved HVPE samples). It is shown that the residual donor density can be reduced by optimization from ?10{sup 17}?cm{sup ?3} to (25)??10{sup 14}?cm{sup ?3}. The density of deep hole traps and deep electron traps decreases with decreased donor density, so that the concentration of deep hole traps in the improved samples is reduced to ?5??10{sup 13}?cm{sup ?3} versus 2.9??10{sup 16}?cm{sup ?3} in the standard samples, with a similar decrease in the electron traps concentration.

  8. Electronic and structural characteristics of zinc-blende wurtzite biphasic homostructure GaN nanowires

    DOE PAGES [OSTI]

    Jacobs, Benjamin W.; Ayres, Virginia M.; Petkov, Mihail P.; Halpern, Joshua B.; He, Maoqi; Baczewski, Andrew D.; McElroy, Kaylee; Crimp, Martin A.; Zhang, Jiaming; Shaw, Harry C.

    2007-04-07

    Here, we report a new biphasic crystalline wurtzite/zinc-blende homostructure in gallium nitride nanowires. Cathodoluminescence was used to quantitatively measure the wurtzite and zinc-blende band gaps. High-resolution transmission electron microscopy was used to identify distinct wurtzite and zinc-blende crystalline phases within single nanowires through the use of selected area electron diffraction, electron dispersive spectroscopy, electron energy loss spectroscopy, and fast Fourier transform techniques. A mechanism for growth is identified.

  9. Highly aligned vertical GaN nanowires using submonolayer metal catalysts

    DOEpatents

    Wang, George T.; Li, Qiming; Creighton, J. Randall

    2010-06-29

    A method for forming vertically oriented, crystallographically aligned nanowires (nanocolumns) using monolayer or submonolayer quantities of metal atoms to form uniformly sized metal islands that serve as catalysts for MOCVD growth of Group III nitride nanowires.

  10. Space-and-time resolved spectroscopy of single GaN nanowires

    DOE PAGES [OSTI]

    Upadhya, Prashanth C.; Martinez, Julio A.; Li, Qiming; Wang, George T.; Swartzentruber, Brian S.; Taylor, Antoinette J.; Prasankumar, Rohit P.

    2015-06-30

    Gallium nitridenanowires have garnered much attention in recent years due to their attractive optical and electrical properties. An understanding of carrier transport, relaxation, and recombination in these quasi-one-dimensional nanosystems is therefore important in optimizing them for various applications. We present ultrafast optical microscopic measurements on single GaNnanowires. Furthermore, our experiments, performed while varying the light polarization,excitation fluence, and position, give insight into the mechanisms governing carrier dynamics in these nanosystems.

  11. "Note: All Others includes Czech Republic, Germany, Hong Kong...

    Energy Information Administration (EIA) (indexed site)

    . Photovoltaic module import shipments by country, 2015" "(peak kilowatts)" ... Source: U.S. Energy Information Administration, Form EIA-63B, 'Annual Photovoltaic Cell...

  12. Germany reconsiders European CO{sub 2}/energy tax

    SciTech Connect

    Wiesmann, G.

    1994-09-28

    The proposal to introduce a European CO{sub 2}/energy tax is still being considered. The ultimate goal of reducing emissions by the year 2000 will not be realized unless current policy includes an integrated package of laws and reforms. Most likely, transport users and domestic consumers - not industry - would be the target of such taxation.

  13. DECOMMISSIONING OF NUCLEAR FACILITIES IN GERMANY - STATUS AT BMBF SITES

    SciTech Connect

    Papp, R.; Komorowski, K.

    2002-02-25

    In a period of approximately 40 years prior to 1994, the German Federal Government had spent about {approx} 15 billion to promote nuclear technology. These funds were earmarked for R&D projects as well as demonstration facilities which took up operation between 1960 and 1980. These BMBF (Federal Ministry for Research) facilities were mainly located at the sites of the federal research centers at Juelich and Karlsruhe (the research reactors AVR, FR2, FRJ-1, KNK, and MZFR, the pilot reprocessing plant WAK) but included also the pilot plants SNR-300 and THTR-300 for fast breeder and high-temperature gas-cooled reactor development, respectively, and finally the salt mine Asse which had been used for waste emplacement prior to conversion into an underground research laboratory. In the meantime, almost all of these facilities were shut down and are now in a state of decommissioning and dismantling. This is mainly due to the facts that R&D needs are satisfied or do not exist any more and that, secondly, the lack of political consensus led to the cancellation of advanced nuclear technology.

  14. EUDEEP (Smart Grid Project) (Germany) | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    technical and nontechnical barriers that prevent a massive deployment of distributed energy resources (DER) in Europe. In partnership with manufacturers, research organizations,...

  15. Decontamination of hot cells K-1, K-3, M-1, M-3, and A-1, M-Wing, Building 200: Project final report Argonne National Laboratory-East

    SciTech Connect

    Cheever, C.L.; Rose, R.W.

    1996-09-01

    The purpose of this project was to remove radioactively contaminated materials and equipment from the hot cells, to decontaminate the hot cells, and to dispose of the radioactive waste. The goal was to reduce stack releases of Rn-220 and to place the hot cells in an emptied, decontaminated condition with less than 10 {micro}Sv/h (1 mrem/h) general radiation background. The following actions were needed: organize and mobilize a decontamination team; prepare decontamination plans and procedures; perform safety analyses to ensure protection of the workers, public, and environment; remotely size-reduce, package, and remove radioactive materials and equipment for waste disposal; remotely decontaminate surfaces to reduce hot cell radiation background levels to allow personnel entries using supplied air and full protective suits; disassemble and package the remaining radioactive materials and equipment using hands-on techniques; decontaminate hot cell surfaces to remove loose radioactive contaminants and to attain a less than 10 {micro}Sv/h (1 mrem/h) general background level; document and dispose of the radioactive and mixed waste; and conduct a final radiological survey.

  16. Investigation of LaxSr1-xCoyM1-yO3-d (M = Mn Fe) perovskite materials as thermochemical energy storage media.

    DOE PAGES [OSTI]

    Babiniec, Sean Michael; Ambrosini, Andrea; Coker, Eric Nicholas; Miller, James E.

    2015-06-23

    Materials in the LaxSr1–xCoyMn1–yO3–δ (LSCM) and LaxSr1–xCoyFe1–yO3–δ (LSCF) families are candidates for high-temperature thermochemical energy storage due to their facility for cyclic endothermic reduction and exothermic oxidation. A set of 16 LSCM and 21 LSCF compositions were synthesized by a modified Pechini method and characterized by powder X-ray diffraction and thermogravimetric analysis. All materials were found to be various symmetries of the perovskite phase. LSCM was indexed as tetragonal, cubic, rhombohedral, or orthorhombic as a function of increased lanthanum content. For LSCF, compositions containing low lanthanum content were indexed as cubic while materials with high lanthanum content were indexed asmore » rhombohedral. An initial screening of redox activity was completed by thermogravimetric analysis for each composition. The top three compositions with the greatest recoverable redox capacity for each family were further characterized in equilibrium thermogravimetric experiments over a range of temperatures and oxygen partial pressures. As a result, these equilibrium experiments allowed the extraction of thermodynamic parameters for LSCM and LSCF compositions operated in thermochemical energy storage conditions.« less

  17. Investigation of LaxSr1-xCoyM1-yO3-δ (M = Mn Fe) perovskite materials as thermochemical energy storage media

    DOE PAGES [OSTI]

    Babiniec, Sean Michael; Coker, Eric Nicholas; Miller, James E.; Ambrosini, Andrea

    2015-06-23

    Materials in the LaxSr1–xCoyMn1–yO3–δ (LSCM) and LaxSr1–xCoyFe1–yO3–δ (LSCF) families are candidates for high-temperature thermochemical energy storage due to their facility for cyclic endothermic reduction and exothermic oxidation. A set of 16 LSCM and 21 LSCF compositions were synthesized by a modified Pechini method and characterized by powder X-ray diffraction and thermogravimetric analysis. All materials were found to be various symmetries of the perovskite phase. LSCM was indexed as tetragonal, cubic, rhombohedral, or orthorhombic as a function of increased lanthanum content. For LSCF, compositions containing low lanthanum content were indexed as cubic while materials with high lanthanum content were indexed asmore » rhombohedral. An initial screening of redox activity was completed by thermogravimetric analysis for each composition. The top three compositions with the greatest recoverable redox capacity for each family were further characterized in equilibrium thermogravimetric experiments over a range of temperatures and oxygen partial pressures. As a result, these equilibrium experiments allowed the extraction of thermodynamic parameters for LSCM and LSCF compositions operated in thermochemical energy storage conditions.« less

  18. The effect of cigarette smoke and arsenic exposure on urothelial carcinoma risk is modified by glutathione S-transferase M1 gene null genotype

    SciTech Connect

    Chung, Chi-Jung [Department of Health Risk Management, College of Public Health, China Medical University, Taichung, Taiwan (China) [Department of Health Risk Management, College of Public Health, China Medical University, Taichung, Taiwan (China); Department of Medical Research, China Medical University Hospital, Taichung, Taiwan (China); Huang, Chao-Yuan; Pu, Yeong-Shiau [Department of Urology, National Taiwan University Hospital, Taipei, Taiwan (China)] [Department of Urology, National Taiwan University Hospital, Taipei, Taiwan (China); Shiue, Horng-Sheng [Department of Chinese Medicine, Chang Gung Memorial Hospital, Taipei, Taiwan (China)] [Department of Chinese Medicine, Chang Gung Memorial Hospital, Taipei, Taiwan (China); Su, Chien-Tien [Department of Family Medicine, Taipei Medical University Hospital, Taipei, Taiwan (China)] [Department of Family Medicine, Taipei Medical University Hospital, Taipei, Taiwan (China); Hsueh, Yu-Mei, E-mail: ymhsueh@tmu.edu.tw [Department of Public Health, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China) [Department of Public Health, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China)

    2013-01-15

    Inter-individual variation in the metabolism of xenobiotics, caused by factors such as cigarette smoking or inorganic arsenic exposure, is hypothesized to be a susceptibility factor for urothelial carcinoma (UC). Therefore, our study aimed to evaluate the role of geneenvironment interaction in the carcinogenesis of UC. A hospital-based casecontrol study was conducted. Urinary arsenic profiles were measured using high-performance liquid chromatographyhydride generator-atomic absorption spectrometry. Genotyping was performed using a polymerase chain reaction-restriction fragment length polymorphism technique. Information about cigarette smoking exposure was acquired from a lifestyle questionnaire. Multivariate logistic regression was applied to estimate the UC risk associated with certain risk factors. We found that UC patients had higher urinary levels of total arsenic, higher percentages of inorganic arsenic (InAs%) and monomethylarsonic acid (MMA%) and lower percentages of dimethylarsinic acid (DMA%) compared to controls. Subjects carrying the GSTM1 null genotype had significantly increased UC risk. However, no association was observed between gene polymorphisms of CYP1A1, EPHX1, SULT1A1 and GSTT1 and UC risk after adjustment for age and sex. Significant geneenvironment interactions among urinary arsenic profile, cigarette smoking, and GSTM1 wild/null polymorphism and UC risk were observed after adjustment for potential risk factors. Overall, geneenvironment interactions simultaneously played an important role in UC carcinogenesis. In the future, large-scale studies should be conducted using tag-SNPs of xenobiotic-metabolism-related enzymes for gene determination. -- Highlights: ? Subjects with GSTM1 null genotype had significantly increased UC risk. ? UC patients had poor arsenic metabolic ability compared to controls. ? GSTM1 null genotype may modify arsenic related UC risk.

  19. Cutoff walls and cap for lime and M-1 settling basins, Rocky Mountain Arsenal, Colorado. Part 1: Final design analysis. Final report

    SciTech Connect

    1990-10-01

    This document consists of 2 parts, final design analysis and specifications. The purpose of the project was to develop a design for the Interim Response Actions (IRA) at the Lime and M-l Settling Basins at Rocky Mountain Arsenal (RMA), Commerce City, Colorado. The purpose of the IRA at the Lime and M-l Settling Basins is to mitigate the threat of release from the Basins on an interim basis, pending determination of the final remedy in the Onpost Record of Decision (ROD). The IRA for the M-l Basins also includes treatment of the waste materials in the basins with in-situ vitrification (ISV), which is being designed by contract with Woodward-Clyde Consultants.

  20. The Doral Group Ltd | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Group Ltd Jump to: navigation, search Name: The Doral Group Ltd. Place: Ramat Gan, Israel Product: Ramat Gan-based investment, development and holding company. References: The...

  1. Direct transparent electrode patterning on layered GaN substrate by screen printing of indium tin oxide nanoparticle ink for Eu-doped GaN red light-emitting diode

    SciTech Connect

    Kashiwagi, Y. Yamamoto, M.; Saitoh, M.; Takahashi, M.; Ohno, T.; Nakamoto, M.; Koizumi, A.; Fujiwara, Y.; Takemura, Y.; Murahashi, K.; Ohtsuka, K.; Furuta, S.

    2014-12-01

    Transparent electrodes were formed on Eu-doped GaN-based red-light-emitting diode (GaN:Eu LED) substrates by the screen printing of indium tin oxide nanoparticle (ITO np) inks as a wet process. The ITO nps with a mean diameter of 25?nm were synthesized by the controlled thermolysis of a mixture of indium complexes and tin complexes. After the direct screen printing of ITO np inks on GaN:Eu LED substrates and sintering at 850?C for 10?min under atmospheric conditions, the resistivity of the ITO film was 5.2?m??cm. The fabricated LED up to 3?mm square surface emitted red light when the on-voltage was exceeded.

  2. Phase-Field Simulations of GaN Growth by Selective Area Epitaxy on Complex Mask Geometries

    SciTech Connect

    Aagesen, Larry K.; Coltrin, Michael Elliott; Han, Jung; Thornton, Katsuyo

    2015-05-15

    Three-dimensional phase-field simulations of GaNgrowth by selective area epitaxy were performed. Furthermore, this model includes a crystallographic-orientation-dependent deposition rate and arbitrarily complex mask geometries. The orientation-dependent deposition rate can be determined from experimental measurements of the relative growth rates of low-index crystallographic facets. Growth on various complex mask geometries was simulated on both c-plane and a-plane template layers. Agreement was observed between simulations and experiment, including complex phenomena occurring at the intersections between facets. The sources of the discrepancies between simulated and experimental morphologies were also investigated. We found that the model provides a route to optimize masks and processing conditions during materials synthesis for solar cells, light-emitting diodes, and other electronic and opto-electronic applications.

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

    SciTech Connect

    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.

  4. Combined Retrieval, Microphysical Retrievals and Heating Rates

    DOE Data Explorer

    Feng, Zhe

    2013-02-22

    Microphysical retrievals and heating rates from the AMIE/Gan deployment using the PNNL Combined Retrieval.

  5. Combined Retrieval, Microphysical Retrievals and Heating Rates

    DOE Data Explorer

    Feng, Zhe

    Microphysical retrievals and heating rates from the AMIE/Gan deployment using the PNNL Combined Retrieval.

  6. “Nodal Gap” induced by the incommensurate diagonal spin density modulation in underdoped high- Tc superconductors

    SciTech Connect

    Zhou, Tao; Gao, Yi; Zhu, Jian -Xin

    2015-03-07

    Recently it was revealed that the whole Fermi surface is fully gapped for several families of underdoped cuprates. The existence of the finite energy gap along the d-wave nodal lines (nodal gap) contrasts the common understanding of the d-wave pairing symmetry, which challenges the present theories for the high-Tcsuperconductors. Here we propose that the incommensurate diagonal spin-density-wave order can account for the above experimental observation. The Fermi surface and the local density of states are also studied. Our results are in good agreement with many important experiments in high-Tcsuperconductors.

  7. Lambda network having 2.sup.m-1 nodes in each of m stages with each node coupled to four other nodes for bidirectional routing of data packets between nodes

    DOEpatents

    Napolitano, Jr., Leonard M.

    1995-01-01

    The Lambda network is a single stage, packet-switched interprocessor communication network for a distributed memory, parallel processor computer. Its design arises from the desired network characteristics of minimizing mean and maximum packet transfer time, local routing, expandability, deadlock avoidance, and fault tolerance. The network is based on fixed degree nodes and has mean and maximum packet transfer distances where n is the number of processors. The routing method is detailed, as are methods for expandability, deadlock avoidance, and fault tolerance.

  8. Cytotoxicity of settling particulate matter and sediments of the Neckar River (Germany) during a winter flood

    SciTech Connect

    Hollert, H.; Duerr, M.; Erdinger, L.; Braunbeck, T.

    2000-03-01

    To investigate the cytotoxic and genotoxic potentials of settling particulate matter (SPM) carried by the Neckar River, a well-studied model for a lock-regulated river in central Europe, during a flood, acute cytotoxicity was investigated using the fibroblast-like fish cell line RTG-2 with the neutral red retention, the succinic acid dehydrogenase (MTT), and the lactatedehydrogenase (LDH) release assays as well as microscopic inspection as endpoints. Genotoxicity of water, pore water, sediments, and SPM were assessed using the Ames test. Different extraction methods (Soxhlet extraction with solvents of variable polarity as well as a fluid/fluid extraction according to pH) in addition to a supplementation of biotests with 59 fractions from the liver of {beta}-naphthoflavone/phenobarbital-induced rats allowed a further characterization of the biological damage. Both sediments and SPM extracts caused cytotoxic effects in RTG-2 cells. Cytotoxicity was found to increase significantly with polarity of extracting solvents. Following extraction according to pH, cytotoxicity could be attributed mainly to neutral substances, whereas the slightly acid and basic fractions already showed little or no cytotoxicity. Samples taken during the period of flood rise showed the highest cytotoxic activities. Cytotoxicity was significantly enhanced by the addition of S9 preparations. In contrast, no genotoxic activity was found in native surface waters, pore waters, and SPM.

  9. Release and disposal of materials during decommissioning of Siemens MOX fuel fabrication plant at Hanau, Germany

    SciTech Connect

    Koenig, Werner; Baumann, Roland

    2007-07-01

    In September 2006, decommissioning and dismantling of the Siemens MOX Fuel Fabrication Plant in Hanau were completed. The process equipment and the fabrication buildings were completely decommissioned and dismantled. The other buildings were emptied in whole or in part, although they were not demolished. Overall, the decommissioning process produced approximately 8500 Mg of radioactive waste (including inactive matrix material); clearance measurements were also performed for approximately 5400 Mg of material covering a wide range of types. All the equipment in which nuclear fuels had been handled was disposed of as radioactive waste. The radioactive waste was conditioned on the basis of the requirements specified for the projected German final disposal site 'Schachtanlage Konrad'. During the pre-conditioning, familiar processes such as incineration, compacting and melting were used. It has been shown that on account of consistently applied activity containment (barrier concept) during operation and dismantling, there has been no significant unexpected contamination of the plant. Therefore almost all the materials that were not a priori destined for radioactive waste were released without restriction on the basis of the applicable legal regulations (chap. 29 of the Radiation Protection Ordinance), along with the buildings and the plant site. (authors)

  10. DISMANTLING OF THE UPPER RPV COMPONENTS OF THE KARLSRUHE MULTI-PURPOSE RESEARCH REACTOR (MZFR), GERMANY

    SciTech Connect

    Prechtl, E.; Suessdorf, W.

    2003-02-27

    The Multi-purpose Research Reactor was a pressurized-water reactor cooled and moderated with heavy water. It was built from 1961 to 1966 and went critical for the first time on 29 September 1965. After nineteen years of successful operation, the reactor was de-activated on 3 May 1984. The reactor had a thermal output of 200 MW and an electrical output of 50 MW. The MZFR not only served to supply electrical power, but also as a test bed for: - research into various materials for reactor building (e. g. zirkaloy), - the manufacturing and operating industry to gain experience in erection and operation, - training scientific and technical reactor staff, and - power supply (first nuclear combined-heat-and-power system, 1979-1984). The experience gained in operating the MZFR was very helpful for the development and operation of power reactors. At first, safe containment and enclosure of the plant was planned, but then it was decided to dismantle the plant completely, step by step, in view o f the clear advantages of this approach. The decommissioning concept for the complete elimination of the plant down to a green-field site provides for eight steps. A separate decommissioning license is required for each step. As part of the dismantling, about 72,000 Mg [metric tons] of concrete and 7,200 Mg of metal (400 Mg RPV) must be removed. About 700 Mg of concrete (500 Mg biological shield) and 1300 Mg of metal must be classified as radioactive waste.

  11. The legal status of UF{sub 6}-cylinder testing and licensing in Germany (and Europe)

    SciTech Connect

    Wieser, K.E.; Tietze, A.

    1991-12-31

    New German and European transport regulations for road and rail transport of UF{sub 6}-cylinders are presented, in particular those provisions which have direct impact on the majority of cylinders used in shipments touching ADR and RID member states. First experiences and difficulties in it`s application are highlighted taking into account experiences of a for running German regulation. A summary of research efforts on the behaviour of cylinders in fire environments concludes the paper.

  12. Foreign Travel Report - West Germany and Belgium - September 9 - September 13, 1985

    SciTech Connect

    Bickford, D.F.

    2001-05-17

    This report discusses visitation of the PAMELA plant which provided an opportunity to observe the operation and design of this European waste solidification facility. The aim of the workshop was to exchange expertise relative to the safe vitrification of HLLW in order to determine which areas were technologically solved and which areas required further study.

  13. Lidar for remote sensing; Proceedings of the Meeting, Berlin, Germany, June 24-26, 1992

    SciTech Connect

    Becherer, R.J.; Werner, C.

    1992-01-01

    The present volume on lidar for remote sensing discusses lidar system techniques for remote sensing of atmospheric pollution, airborne and surface-based lidar for environmental sensing of water and oceans, Doppler lidar for wind sensing and related measurement, aerosol measurements using lidar, ozone, water vapor, temperature, and density sensing with lidar systems, and new lidar technology systems and concepts. Attention is given to remote sensing of air pollution over large European cities by lidar, differential absorption lidar monitoring of atmospheric atomic mercury, an experimental evaluation of an airborne depth-sounding lidar, and remote sensing of the sea by tunable multichannel lidar. Topics addressed include recent developments in lidar techniques to measure the wind in the middle atmosphere, recent stratospheric aerosol measurements with a combined Raman elastic-backscatter lidar, the development of an eye-safe IR aerosol lidar, and temperature measurement by rotational Raman lidar.

  14. Diagenesis and fluid evolution of deeply buried Permian (Rotliegende) gas reservoirs, Northwest Germany

    SciTech Connect

    Gaupp, R. ); Matter, A.; Ramseyer, K.; Platt, J. ); Walzebuck, J. )

    1993-07-01

    Depositional environment and tectonic setting were important in the diagenesis and evolution of reservoir properties in the Rotliegende sequence of the North German Basin. Facies belts paralleling the edge of a central saline lake controlled the distribution of early and shallow burial cements. Lake shoreline sands with radial chlorite cement show the best reservoir properties in the study area. Juxtaposition of Rotliegende deposits against either Carboniferous Coal Measures or Late Permian (Zechstein) evaporites by faulting resulted in cross-formational fluid exchange. The introduction of fluids from Carboniferous Coal Measures into Rotliegende reservoirs produced intense clay cementation, significantly reducing rock permeabilities. Influx of Zechstein fluids favored precipitation of late carbonate and anhydrite cements. Cross-formational and fault-related fluid flow was enhanced during periods of fault activity. 50 refs., 15 figs., 1 tab.

  15. Visible-light absorption and large band-gap bowing of GaN1-xSbx from first principles

    DOE PAGES [OSTI]

    Sheetz, R. Michael; Richter, Ernst; Andriotis, Antonis N.; Lisenkov, Sergey; Pendyala, Chandrashekhar; Sunkara, Mahendra K.; Menon, Madhu

    2011-08-01

    Applicability of the Ga(Sbx)N1-x alloys for practical realization of photoelectrochemical water splitting is investigated using first-principles density functional theory incorporating the local density approximation and generalized gradient approximation plus the Hubbard U parameter formalism. Our calculations reveal that a relatively small concentration of Sb impurities is sufficient to achieve a significant narrowing of the band gap, enabling absorption of visible light. Theoretical results predict that Ga(Sbx)N1-x alloys with 2-eV band gaps straddle the potential window at moderate to low pH values, thus indicating that dilute Ga(Sbx)N1-x alloys could be potential candidates for splitting water under visible light irradiation.

  16. Reliability of AlGaN/GaN high electron mobility transistors on low dislocation density bulk GaN substrate: Implications of surface step edges

    SciTech Connect

    Killat, N. E-mail: Martin.Kuball@bristol.ac.uk; Montes Bajo, M.; Kuball, M. E-mail: Martin.Kuball@bristol.ac.uk; Paskova, T.; Materials Science and Engineering Department, North Carolina State University, Raleigh, North Carolina 27695 ; Evans, K. R.; Leach, J.; Electrical and Computer Engineering Department, Virginia Commonwealth University, Richmond, Virginia 23284 ; Li, X.; Özgür, Ü.; Morkoç, H.; Chabak, K. D.; Crespo, A.; Gillespie, J. K.; Fitch, R.; Kossler, M.; Walker, D. E.; Trejo, M.; Via, G. D.; Blevins, J. D.

    2013-11-04

    To enable gaining insight into degradation mechanisms of AlGaN/GaN high electron mobility transistors, devices grown on a low-dislocation-density bulk-GaN substrate were studied. Gate leakage current and electroluminescence (EL) monitoring revealed a progressive appearance of EL spots during off-state stress which signify the generation of gate current leakage paths. Atomic force microscopy evidenced the formation of semiconductor surface pits at the failure location, which corresponds to the interaction region of the gate contact edge and the edges of surface steps.

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

    SciTech Connect

    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.

  18. ARM - Data Announcements Article

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    the Madden-Julian Oscillation (DYNAMO) and the ARM Madden-Julian Oscillation MJO Investigation Experiment AMIE on Gan Island, or AMIE-Gan field campaign. Due to the lack of a...

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

    Energy.gov [DOE]

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

  20. Solar IT | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    IT Jump to: navigation, search Name: Solar IT Place: Ramat-Gan, Israel Product: Ramat-Gan-based supplier and assemblier of PV-based systems for domestic and industrial use....

  1. News Item

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Switchable Control of Nanowire Growth SEM images of GaN nanowire arrays illustrating their growth orientations with respect to the GaN crystal structure Scientific Achievement A team of multidisciplinary researchers at the Berkeley Lab's Molecular Foundry used catalyst composition to control the crystallographic growth of GaN nanowires Significance and Impact Manipulating GaN nanostructures offers the ability to custom design bulk material properties in unique ways, potentially leading to new

  2. Comparison of the incentives used to stimulate energy production in Japan, France, West Germany, and the United States

    SciTech Connect

    Cole, R.J.; Sommers, P.; Eschbach, C.; Sheppard, W.J.; Lenerz, D.E.; Huelshoff, M.; Marcus, A.A.

    1981-09-01

    This volume represents the culmination of a five-year research effort examining the incentives used to stimulate energy production in four countries, and the incentives used to stimulate energy consumption in one country. Following the theoretical approach developed for studying US energy incentives, the researchers in each country classified incentives into the following six categories: (1) Taxation, including exemption from or reduction of existing taxes; (2) Disbursements, in which the national government distributes money without requiring anything in return; (3) Requirements, including demands made by the government, backed by civil or criminal sanctions; (4) Traditional Services, including those almost always provided exclusively by a governmental entity; (5) Nontraditional Services, including those sometimes performed by non-governmental entities, as well as governmental entities (e.g., research and development); and (6) Market Activities, including government involvement in the market under conditions similar to those faced by non-governmental producers or consumers. A complete list of research reports prepared in the Federal Incentives series is provided in the Appendix.

  3. Prediction and development of Zechstein 2 carbonate reservoirs in the West-Emsland area, upper Permian, northwest Germany

    SciTech Connect

    Werner, D.; Strohmenger, C.

    1995-08-01

    The integration of facies, well log, and seismic data within a sequence stratigraphic framework of the Basal Zechstein led to a 3-D model of the reservoir facies distribution. The model improved the reconstruction of the depositional history with respect to preexisting topography, eustatic sea-level changes, and structural setting. The subdivision of the Zechstein 2 carbonate (Ca2) into 25 subfacies types, based on detailed core descriptions, enables the localization of depositional environments (supra-, inter-, and shallow subtidal for the platform facies; upper, middle, lower slope and basin for the deeper-marine facies). The Ca2 represents a complete 3rd-order sequence Vertical subfacies successions and their specific gamma-ray and sonic-log responses allow the identification of systems tracts and shallowing upward parasequences within the Ca2. The lateral extent of porous zones has been mapped by integrating parasequence sets and petrophysical data in chronostratigraphic well-log correlations. Thickness relationships among the Ca2, the underlying Werra Anhydite (A1), and the overlying Basal Anhydrite (A2) and the Staffurt Salt (Na2) serve as an additional prediction tool of Ca2-facies distribution due to abrupt thickness changes of these lithologic units in a predominant prograding platform-to-basin-architecture. Dolomitic Ca2 facies were deposited as late-highstand and lowstand-wedge shoal and bar complexes at the end of Ca2 time, and lie between the A1- and the A2-platform margins. 3-D seismic interpretations coincide with the high-resolution correlations. delineate the limiting margins, and additionally detect syndepositional tectonics, which caused anomalies in Ca2 thickness and facies distribution. High seismic amplitudes at the base of the Ca2 and low impedance indicate good reservoir quality. However, variations in Ca2 thickness, lithology (grade of anhydritization) and pore content, render the interpretations of attribute anomalies difficult.

  4. Zechstein 2 carbonate reservoir prediction and development in the West-Emsland area, upper Permian, Northwest Germany - an integrated approach

    SciTech Connect

    Werner, D.; Strohmenger, C.

    1995-08-01

    The Zechstein 2 Carbonate (Ca2) comprises a complete 3rd-order sequence, which is subdivided into seven parasequences recognized by subfacies successions in cores and combined gamma-ray and sonic-log responses. Besides higher-order sea-level changes and synsedimentary structuring, the paleotopography built by the underlying Wena-Anhydrite (A1) controlled the deposition of the Ca2. The Al-platform was extensively karstified during a third-order sea-level lowstand at the end of A1 time and during the early transgressive phase of the Ca2-basin and slope deposition. The Ca2 maximum flooding corresponds to the inundation of the A1-platform and the filling of the A1-karst cavities. Four shallowing-upward parasquences represent the Ca2-highstand systems tract on the platform. They are defined by flooding surfaces in cores and by an abrupt increase in sonic velocity. High energy, shallow subtidal facies at the base of each parasequence pass gradually upward into tidal flat facies and, at the top of the 5th (and the 6th) Ca2-parasequence(s), even into supratidal sabkha facies. A lowstand wedge, which prograded over thick upper and middle slope facies at the end of Ca2 time, expands the reservoir basinward. Correlating these potential pay zones in cores and well logs finally led to a 3-D model of the reservoir architecture. Thickness relationships among the A1, the Ca2, and the overlying Basal Anhydrite (A2) and the StaBfurt Salt (Na2), emphasized by abrupt thickness changes of these lithologic units in a predominant prograding geometry, help to predict top-Ca2 facies belts. The dramatic thickness changes occur at the A1- and the A2-platform margins, limiting the most prospective reservoir zone. 3-D seismic interpretations delineate these margins and support the reservoir characterization by seismic attribute analysis.

  5. Quantitative comparison between PGNAA measurements and MCNP calculations in view of the characterization of radioactive wastes in Germany and France

    SciTech Connect

    Mauerhofer, E.; Havenith, A.; Kettler, J.; Carasco, C.; Payan, E.; Ma, J. L.; Perot, B.

    2013-04-19

    The Forschungszentrum Juelich GmbH (FZJ), together with the Aachen University Rheinisch-Westfaelische Technische Hochschule (RWTH) and the French Alternative Energies and Atomic Energy Commission (CEA Cadarache) are involved in a cooperation aiming at characterizing toxic and reactive elements in radioactive waste packages by means of Prompt Gamma Neutron Activation Analysis (PGNAA). The French and German waste management agencies have indeed defined acceptability limits concerning these elements in view of their projected geological repositories. A first measurement campaign was performed in the new Prompt Gamma Neutron Activation Analysis (PGNAA) facility called MEDINA, at FZJ, to assess the capture gamma-ray signatures of some elements of interest in large samples up to waste drums with a volume of 200 liter. MEDINA is the acronym for Multi Element Detection based on Instrumental Neutron Activation. This paper presents MCNP calculations of the MEDINA facility and quantitative comparison between measurement and simulation. Passive gamma-ray spectra acquired with a high purity germanium detector and calibration sources are used to qualify the numerical model of the crystal. Active PGNAA spectra of a sodium chloride sample measured with MEDINA then allow for qualifying the global numerical model of the measurement cell. Chlorine indeed constitutes a usual reference with reliable capture gamma-ray production data. The goal is to characterize the entire simulation protocol (geometrical model, nuclear data, and postprocessing tools) which will be used for current measurement interpretation, extrapolation of the performances to other types of waste packages or other applications, as well as for the study of future PGNAA facilities.

  6. New Design for an HLW Repository (for Spent Fuel and Waste from Reprocessing) in a Salt Formation in Germany - 12213

    SciTech Connect

    Bollingerfehr, Wilhelm; Filbert, Wolfgang; Lerch, Christian; Mueller-Hoeppe, Nina; Charlier, Frank

    2012-07-01

    In autumn 2010, after a 10-year moratorium, exploration was resumed in Gorleben, the potential site for a German HLW repository. At the same time, the Federal Government launched a two-year preliminary safety analysis to assess whether the salt dome at Gorleben is suitable to host all heat-generating radioactive waste generated by German NPPs based on the waste amounts expected at that time. The revised Atomic Energy Act of June 2011 now stipulates a gradual phase-out of nuclear energy production by 2022, which is 13 years earlier than expected in 2010. A repository design was developed which took into account an updated set of data on the amounts and types of expected heat-generating waste, the documented results of the exploration of the Gorleben salt dome, and the new 'Safety Requirements Governing the Final Disposal of Heat-Generating Radioactive Waste' of 30 September, 2010. The latter has a strong influence on the conceptual designs as it requires that retrievability of all waste containers is possible within the repository lifetime. One design considered that all waste containers will be disposed of in horizontal drifts of a geologic repository, while the other design considered that all waste containers will be disposed of in deep vertical boreholes. For both options (emplacement in drifts/emplacement in vertical boreholes), the respective design includes a selection of waste containers, the layout of drifts, respectively lined boreholes, a description of emplacement fields, and backfilling and sealing measures. The design results were described and displayed and the differences between the two main concepts were elaborated and discussed. For the first time in both repository designs the requirement was implemented to retrieve waste canisters during the operational phase. The measures to fulfill this requirement and eventually the consequences were highlighted. It was pointed out that there arises the need to keep transport- and storage casks in adequate numbers and interim storage facilities available until the repository is closed. (authors)

  7. WIPP, Carlsbad Host Department of State Conference | Department...

    Energy.gov [DOE] (indexed site)

    ... salt taken from the Morsleben mine in Germany. WIPP Shares Expertise with Salt Club Members Participants in the workshops in Germany toured Asse II, one of Germany's two ...

  8. WIPP Attracts International Interest | Department of Energy

    Office of Environmental Management (EM)

    ... salt taken from the Morsleben mine in Germany. WIPP Shares Expertise with Salt Club Members Participants in the workshops in Germany toured Asse II, one of Germany's two ...

  9. EEnergy Project "MeRegio" (Smart Grid Project) (Baden-Wrttemberg...

    OpenEI (Open Energy Information) [EERE & EIA]

    Baden-Wrttemberg, Germany) Jump to: navigation, search Project Name EEnergy Project "MeRegio" Country Germany Headquarters Location Baden-Wrttemberg, Germany Coordinates...

  10. Center for Energy Nanoscience at USC

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    LED Nanowire LEDs GaN based light emitting diodes (LEDs) are a key technology for high brightness LEDs. Although already successful commercially, fundamental physical and device...

  11. Beamline 10.3.1

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Trace-element analysis with high spatial resolution (e.g., silicon solar cells, GaN, atmospheric particulates, environmental soil samples, and biological samples) Scientific...

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

    Energy.gov [DOE]

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

  13. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    ... Office of Nonproliferation and National Security (NN) (United States) USDOE Office of ... GaN electrodes for electrolysis, water splitting, or photosynthetic process applications. ...

  14. Sandia Energy - Solid-State Lighting

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Energy Efficiency Permalink Gallery Assessment of deep level defects in m-plane GaN grown by metalorganic chemical vapor deposition Energy Efficiency, News, News & Events,...

  15. Beamline 10.3.1

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    depending on configuration. Sample environment Air and vacuum Scientific applications Trace-element analysis with high spatial resolution (e.g., silicon solar cells, GaN,...

  16. Shikun Binui Arison Group | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Ramat Gan, Israel Zip: 55215 Product: String representation "Shikun & Binui ... gy and ecology." is too long. References: Shikun & Binui Arison Group1 This article is a stub. You...

  17. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Xiao Mei ; Du, Zehui ; Schuh, Christopher A. ; Tamura, Nobumichi ; Gan, Chee Lip April 2016 , Elsevier Prev Next Switch to Detail View for this search SOLR Query Details

  18. Main Title 32pt

    Energy.gov [DOE] (indexed site)

    ... methods * Develop initial fluid dynamics schemes * Deposit GaN on a seed crystal * Improve crystal quality * Optimize growth rate 2- P. G. Rickert et al. ...

  19. ARM - ARM MJO Investigation Experiment (AMIE)

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    ARM MJO Investigation Experiment (AMIE) ARM field campaigns on Gan Island, Maldives, and Manus Island, Papua New Guinea, will contribute significantly to concurrent national and ...

  20. Field Mapping At Raft River Geothermal Area (1993) | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    extension over broad areas of the northern Basin and Range. References Dumitru, T.; Miller, E.; Savage, C.; Gans, P.; Brown, R. (1 April 1993) Fission track evidence for...

  1. Fission track evidence for widespread early to Middle miocene...

    OpenEI (Open Energy Information) [EERE & EIA]

    major extension over broad areas of the northern Basin and Range. Authors Dumitru, T.; Miller, E.; Savage, C.; Gans, P.; Brown and R. Published Geological Society of America,...

  2. Field Mapping At Northern Basin and Range Geothermal Region ...

    OpenEI (Open Energy Information) [EERE & EIA]

    extension over broad areas of the northern Basin and Range. References Dumitru, T.; Miller, E.; Savage, C.; Gans, P.; Brown, R. (1 April 1993) Fission track evidence for...

  3. Beamline 10.3.1

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    resolution (e.g., silicon solar cells, GaN, atmospheric particulates, environmental soil samples, and biological samples) Scientific disciplines Environmental science,...

  4. Summer 2010 Internship Projects | Center for Energy Efficient...

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    The Power of Heat: Utilizing Thermoelectric Power Generation to Cool Computer ... Sztein Shuji Nakamura CCS Physics Thermoelectric Properties of GaN and InGaN Based ...

  5. Housing and Construction Holding Company | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Housing and Construction Holding Company Jump to: navigation, search Name: Housing and Construction Holding Company Place: Ramat-Gan, Israel Zip: 52215 Product: Israel-based...

  6. Measurement of mean inner potential and inelastic mean free path...

    Office of Scientific and Technical Information (OSTI)

    Authors: Gan, Zhaofeng ; Ahn, Seungho ; Yu, Hongbin ; Smith, David J. ; McCartney, Martha R. Publication Date: 2015-10-01 OSTI Identifier: 1238990 GrantContract Number: ...

  7. Growth process for gallium nitride porous nanorods

    DOEpatents

    Wildeson, Isaac Harshman; Sands, Timothy David

    2015-03-24

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

  8. Search for: All records | DOE PAGES

    Office of Scientific and Technical Information (OSTI)

    and shape memory behavior of titania and yttria co-doped zirconia Zeng, Xiao Mei ; Du, Zehui ; Schuh, Christopher A. ; Tamura, Nobumichi ; Gan, Chee Lip April 2016 , Elsevier

  9. ASU EFRC - Postdoctoral fellows

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Postdoctoral fellows Barun Das Postdoctoral Fellow Bhupesh Goyal Postdoctoral fellow Jackson Megiatto Postdoctoral Fellow Lu Gan Postdoctoral fellow Matthieu Koepf Postdoctoral...

  10. Publications, 2013 | MIT-Harvard Center for Excitonics

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    ... "External Quantum Efficiency Above 100% in a Singlet-Exciton-Fission-Based Organic Photovoltaic Cell," Science 340, 334 (2013); DOI: 10.1126science.1232994. Gan, Xuetao; ...

  11. Resonant energy transfer between Eu luminescent sites and their...

    Office of Scientific and Technical Information (OSTI)

    Resonant energy transfer between Eu luminescent sites and their local geometry in GaN Citation Details In-Document Search Title: Resonant energy transfer between Eu luminescent ...

  12. Intrinsic Semiconductor | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

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

  13. Cree Inc | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

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

  14. Change in equilibrium position of misfit dislocations at the...

    Office of Scientific and Technical Information (OSTI)

    Our results highlight a direct correlation between threading-dislocation density in GaN ... Department of Materials Science and Engineering and Research Institute of Advanced ...

  15. KOH based selective wet chemical etching of AlN, AlxGa1-xN, and GaN crystals: A way towards substrate removal in deep ultraviolet-light emitting diode

    SciTech Connect

    Guo, W; Kirste, R; Bryan, I; Bryan, Z; Hussey, L; Reddy, P; Tweedie, J; Collazo, R; Sitar, Z

    2015-02-23

    A controllable and smooth potassium hydroxide-based wet etching technique was developed for the AlGaN system. High selectivity between AlN and AlxGa1-xN (up to 12 x) was found to be critical in achieving effective substrate thinning or removal for AlGaN-based deep ultraviolet light emitting diodes, thus increasing light extraction efficiency. The mechanism of high selectivity of AlGaN as a function of Al composition can be explained as related to the formation and dissolution of oxide/hydroxide on top of N-polar surface. Cross-sectional transmission electron microscopic analysis served as ultimate proof that these hillocks were not related to underlying threading dislocations. (C) 2015 AIP Publishing LLC.

  16. Vehicle Technologies Office Merit Review 2016: Advanced Low-Cost SiC and GaN Wide Bandgap Inverters for Under-the-Hood Electric Vehicle Traction Drives

    Office of Energy Efficiency and Renewable Energy (EERE)

    Presentation given by Wolfspeed at the 2016 DOE Vehicle Technologies Office and Hydrogen and Fuel Cells Program Annual Merit Review and Peer Evaluation Meeting about Electric Drive Systems

  17. Proceedings of the fifth annual NEA-seabed working group meeting...

    Office of Scientific and Technical Information (OSTI)

    European Communities, the Federal Republic of Germany, France, Japan, Netherlands, ... COMMUNITIES; FEDERAL REPUBLIC OF GERMANY; FRANCE; GOVERNMENT POLICIES; JAPAN; ...

  18. Dirkshof Erneuerbare Energien | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    to: navigation, search Name: Dirkshof Erneuerbare Energien Place: Reuenkge, Germany Zip: 25821 Product: Reuenkge, Germany based project developer. Coordinates:...

  19. Ultra-thin ohmic contacts for p-type nitride light emitting devices

    DOEpatents

    Raffetto, Mark; Bharathan, Jayesh; Haberern, Kevin; Bergmann, Michael; Emerson, David; Ibbetson, James; Li, Ting

    2014-06-24

    A flip-chip semiconductor based Light Emitting Device (LED) can include an n-type semiconductor substrate and an n-type GaN epi-layer on the substrate. A p-type GaN epi-layer can be on the n-type GaN epi-layer and a metal ohmic contact p-electrode can be on the p-type GaN epi-layer, where the metal ohmic contact p-electrode can have an average thickness less than about 25 .ANG.. A reflector can be on the metal ohmic contact p-electrode and a metal stack can be on the reflector. An n-electrode can be on the substrate opposite the n-type GaN epi-layer and a bonding pad can be on the n-electrode.

  20. Review of using gallium nitride for ionizing radiation detection

    SciTech Connect

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

    2015-09-15

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

  1. EM International Program Action Table

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Design and Operations N. Buschman, EM-22 Germany Albuquerque & Carlsbad, NM Continue ... and Research (BMBF) G. DeLeon, EM-22 Germany Cologne, Germany Follow-up meeting from ...

  2. Defect-engineered GaN:Mg nanowire arrays for overall water splitting under violet light

    SciTech Connect

    Kibria, M. G.; Chowdhury, F. A.; Zhao, S.; Mi, Z.; Trudeau, M. L.; Guo, H.

    2015-03-16

    We report that by engineering the intra-gap defect related energy states in GaN nanowire arrays using Mg dopants, efficient and stable overall neutral water splitting can be achieved under violet light. Overall neutral water splitting on Rh/Cr{sub 2}O{sub 3} co-catalyst decorated Mg doped GaN nanowires is demonstrated with intra-gap excitation up to 450?nm. Through optimized Mg doping, the absorbed photon conversion efficiency of GaN nanowires reaches ?43% at 375450?nm, providing a viable approach to extend the solar absorption of oxide and non-oxide photocatalysts.

  3. SHE 2015

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Confirmed Participants D. Ackermann, GSI, Germany G. Adamian, BLTP JINR, Russia A. Afanasjev, Mississippi State University, USA N. Aksenov, FLNR JINR, Russia H. Backe, University of Mainz, Germany M. Barbui, TAMU, USA W. Barth, GSI, Germany W. Bassichis, TAMU, USA M. Block, GSI, Germany R. Boll, ORNL, USA N. Brewer, ORNL, USA G. Chubarian, TAMU, USA S. Dmitriev, FLNR JINR, Russia C. Duellman, University of Mainz, Germany K. Eberhardt, University of Mainz, Germany R. Eichler, PSI, Switzerland J.

  4. EUROSOL GmbH | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Germany Zip: 67065 Product: Germany-based engineering contractor and wholesaler of photovoltaic products, such as modules and additional components for PV systems. Coordinates:...

  5. Ingenta | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Germany Zip: D- 82319 Product: Germany-based clean energy developer with a photovoltaic power focus, preparing sustainable investments for institutional investors....

  6. SITIZN Group Holding AG | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    SITIZN Group Holding AG Jump to: navigation, search Name: SITIZN Group Holding AG Place: Riederich, Germany Zip: 72585 Sector: Solar Product: Germany-based solar technology and...

  7. Habdank PV Montagesysteme GmbH Co KG Habdank PV Mounting Systems...

    OpenEI (Open Energy Information) [EERE & EIA]

    Germany Zip: 73037 Product: Germany-based manufacturer of mounting systems for PV installations. References: Habdank PV-Montagesysteme GmbH & Co KG Habdank PV Mounting...

  8. Voith Hydro Ocean Current Technologies | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Ocean Current Technologies Jump to: navigation, search Name: Voith Hydro Ocean Current Technologies Place: Germany Sector: Hydro Product: Germany-based JV between Voith Hydro and...

  9. Arkona Windpark Entwicklungs GmbH | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Place: Stralsund, Mecklenburg-Western Pomerania, Germany Zip: 18439 Sector: Wind energy Product: Offshore wind project developer in Northern Germany. Coordinates:...

  10. Reversible inactivation of CO dehydrogenase with thiol compounds...

    Office of Scientific and Technical Information (OSTI)

    Department of Microbiology, University of Bayreuth, 95440 Bayreuth (Germany) Department of Chemistry, University of Paderborn, 33098 Paderborn (Germany) Institute of Biochemistry ...

  11. EEnergy Project "MeRegio" (Smart Grid Project) | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    Jump to: navigation, search Project Name EEnergy Project "MeRegio" Country Germany Headquarters Location Gppingen, Germany Coordinates 48.703159, 9.653999 Loading map......

  12. Mini Berlin powered by Vattenfall (Smart Grid Project) | Open...

    OpenEI (Open Energy Information) [EERE & EIA]

    Jump to: navigation, search Project Name Mini Berlin powered by Vattenfall Country Germany Headquarters Location Berlin, Germany Coordinates 52.523403, 13.4114 Loading...

  13. WindStrom Innovative Energiesysteme GmbH | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    to: navigation, search Name: WindStrom Innovative Energiesysteme GmbH Place: Edemissen, Germany Zip: 31234 Sector: Wind energy Product: Germany-based wind project developer and...

  14. Pilotprojekt Markisches Viertel (Smart Grid Project) | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    Project) Jump to: navigation, search Project Name Pilotprojekt Markisches Viertel Country Germany Headquarters Location Berlin, Germany Coordinates 52.523403, 13.4114 Loading...

  15. DOE Announces Rescheduled Webinar on the Office of Energy Efficiency...

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    a follow up to the previous June 2013 workshop in Berlin, Germany. Participants included experts from Germany, Japan, the United States, Scandinavia, and the European Commission. ...

  16. PROKON Nord Energiesysteme GmbH | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    GmbH Place: Leer, Lower Saxony, Germany Zip: 26789 Sector: Biomass, Wind energy Product: Germany-based developer of wind and biomass energy power plants. Coordinates:...

  17. Schoenfeldt Kutzeer MDP GmbH | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Schoenfeldt & Kutzeer (MDP) GmbH Place: Drohndorf, Germany Zip: D-06456 Sector: Wind energy Product: Germany-based, specialist in planning, project development and wind-powered...

  18. Vensys Energy AG formerly Vensys Energiesysteme GmbH | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    Vensys Energiesysteme GmbH ) Place: Saarbrcken, Germany Zip: 66115 Sector: Wind energy Product: Wind turbine manufacturer based in Germany. References: Vensys Energy...

  19. Jackie Chen to give keynote address at ISC High performance conference...

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    at ISC High performance conference in Germany - Sandia Energy Energy Search Icon Sandia ... Jackie Chen to give keynote address at ISC High performance conference in Germany Home...

  20. WUFI Basement Module

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    University of Minnesota Subcontractor Fraunhofer IBP, Germany CRADA Partner Target Market... of the WUFI code exist only at Oak Ridge National Laboratory and Fraunhofer IBP, Germany. ...

  1. ARM - Facility News Article

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Collaborations in Atmospheric Science and Observations Discussed in Germany Bookmark and ... In early June, ARM personnel visited the University of Cologne in Germany at the ...

  2. Fact #643: October 4, 2010 Four Cylinder Engine Installations...

    Energy.gov [DOE] (indexed site)

    Germany, Italy, and the United Kingdom from 1999 to 2009. The total amount includes the following countries: Austria, Belgium, Denmark, Eire, Finland, France, Germany, ...

  3. ARM - Facility News Article

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    ARM Mobile Facility Completes Field Campaign in Germany Bookmark and Share Researchers ... and causing flooding in portions of Germany. (Image source: DW-WORLD.DE) Operations ...

  4. Fact #878: June 22, 2015 Plug-in Vehicle Penetration in Selected...

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Austria and Germany data do not include PHEVs, but only BEVs. Austria, Canada, France, and Germany include only passenger cars. Fact 878 Dataset Supporting Information Number of ...

  5. Biography J. Birkholzer

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    University of Technology in Germany in 1994. He joined LBNL in 1994 as geological scientist, left for a management position in his native Germany in 1999, and eventually ...

  6. Biography W. Bollingerfehr

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Department at DBE Technology GmbH, in Peine, Germany. After finishing the Technical University of Hannover in Germany as a civil engineer in 1985 he gained extensive ...

  7. PowerPoint Presentation

    Energy.gov [DOE] (indexed site)

    ... subtitle style www.energy.govEM 8 Germany Ministry of Economics and Technology ... Validation Nuclear Material Disposition Germany Salt Defense Disposal Investigation ...

  8. Selvan Demir | Center for Gas SeparationsRelevant to Clean Energy...

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Phone: 510-643-3832 PhD in Chemistry, University of Cologne, Germany Diplom in Chemistry, University of Cologne, Germany EFRC Research Porous aromatic frameworks (PAFs) combine ...

  9. International Stationary Fuel Cell Demonstration

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    * Plug Power (US)Plug Power (Netherlands) * PEMEAS E-TEK USPEMEAS (Germany) * Vaillant (Germany) * Domel (Slovenia) * Bulgarian Academy of Sciences (Bulgaria) * Gaia ...

  10. ARM - Facility News Article

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Journal Special Issue Includes Mobile Facility Data from Germany Bookmark and Share The ARM Mobile Facility operated in Heselbach, Germany, as part of the COPS surface network. The ...

  11. ARM - Facility News Article

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Microwave Radiometers Put to the Test in Germany Bookmark and Share A 2-channel microwave ... ARM Mobile Facility site in Heselbach, Germany, in 2007. Microwave radiometers (MWRs) ...

  12. Microsoft Word - WIPPInternationalApproach

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    This summer, three graduate students from the Technical University at Clausthal in Germany ... at WIPP will be able to study in Germany. "CBFO has an organization called the ...

  13. main.dvi

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Universit at T ubingen, D-72076 T ubingen, Germany 2 Sektion Physik der Universit at M unchen, D-85748 Garching, Germany Received: date Revised version: date Abstract. ...

  14. ARM - Facility News Article

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    ARM Kiosk Joins International Science Exhibit in Germany Bookmark and Share Outdoor pavilions on the Isle of Mainau in Germany feature energy-related science and technology ...

  15. ARM - Facility News Article

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    AMF Instrument Suite in Germany Bookmark and Share The 1290 MHz wind profiler (foreground) joins the eddy correlation system (background) for the 9-month deployment in Germany. ...

  16. ARM - Data Announcements Article

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    June 30, 2008 Data Announcements Black Forest, Germany, WACR-ARSCL Evaluation Products ... for the ARM Mobile Facility deployment in Heselbach, Germany (3292007 - 122008). ...

  17. ARM - Data Announcements Article

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Forest, Germany deployment. Cloud-screened AOD at five wavelengths (top) and Angstrom exponent (bottom) over a three-month time period at the Black Forest, Germany deployment. ...

  18. Fact #644: October 11, 2010 Share of Diesel Vehicle Sales Decline...

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Germany and Italy have experienced the greatest declines in diesel vehicle sales, though ... western Europe for the countries France, Germany, Italy, and the United Kingdom from 1999 ...

  19. Johanna Huck | Center for Gas SeparationsRelevant to Clean Energy...

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Phone: 510-408-8884 MSc in Chemistry, Technical University Munich, Germany BSc in Chemistry, Technical University Munich, Germany EFRC Research Carbon Capture and Sequestration ...

  20. €18.5 Million in New Research Program Funding Announced, GE...

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    and collaboration models at its European Global Research Center near Munich, Germany. ... Collaborative arrangements exist with some of the leading universities in Germany and ...

  1. ARM - Data Announcements Article

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    VAP for 1192007 at Black Forest, Germany: (top) Brightness temperatures measured ... An example plot from the MWRRET VAP for 1192007 at Black Forest, Germany: (top) ...

  2. 1

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    U.S., German, Russian collaboration conducts first experiments in Germany LOS ALAMOS, ... Schwerionenforschung GmbH (Helmholtz Centre for Heavy Ion Research) in Darmstadt, Germany. ...

  3. International Partnership for Geothermal Technology - 2012 Peer...

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Snake River Geothermal Drilling Project GermanyEU Toward the Understanding of Induced Seismicity in Enhanced Geothermal Systems GermanyEU Toward the Understanding of Induced ...

  4. ARM - Facility News Article

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Data from Field Campaign in Black Forest, Germany, are Red Hot Bookmark and Share During COPS, the ARM Mobile Facility operated in Heselbach, Germany, obtaining measurements ...

  5. Untitled

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    for Solid State Physics Karlsruhe, Germany Entropy Landscape of Materials with ... physics in Gnngen, Germany and obtained his PhD 1976 from the University of Cologne. ...

  6. German Wind Energy Association | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    German Wind Energy Association Place: Osnabrck, Germany Zip: 49074 Sector: Wind energy Product: Assocation for the promotion of wind energy in Germany. References: German Wind...

  7. Concentrator Optics | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Concentrator Optics Jump to: navigation, search Name: Concentrator Optics Place: Marburg, Germany Zip: 35037 Product: A Germany-based company engaged in the design and production...

  8. Nastro Environmental Technology GmbH | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Nastro Environmental Technology GmbH Jump to: navigation, search Name: Nastro Environmental Technology GmbH Place: Meppen, Germany Zip: 49716 Product: Germany-based PV system...

  9. Ralos Group | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Ralos Group Jump to: navigation, search Name: Ralos Group Place: Michelstadt, Germany Zip: D-64720 Sector: Solar Product: Germany-based solar project developer that specialises in...

  10. Ferrostaal eSolar JV | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Ferrostaal eSolar JV Jump to: navigation, search Name: Ferrostaal & eSolar JV Place: Germany Sector: Solar Product: Germany-based solar thermal electricity generation joint...

  11. Gemballa Electronics GmbH | Open Energy Information

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    GmbH Jump to: navigation, search Name: Gemballa Electronics GmbH Place: Kaltenkirchen, Germany Zip: 24586 Product: Germany-based produces semiconductor and silicon components. The...

  12. Corntec GmbH | Open Energy Information

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    GmbH Jump to: navigation, search Name: Corntec GmbH Place: Twist, Lower Saxony, Germany Zip: 49767 Product: Investor in biogas projects in Germany. References: Corntec...

  13. Bernried Erdwarme AG | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Bernried Erdwarme AG Jump to: navigation, search Name: Bernried Erdwarme AG Place: Germany Sector: Geothermal energy Product: Germany-based geothermal development company....

  14. VWind AG | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    VWind AG Jump to: navigation, search Name: VWind AG Place: Germany Sector: Wind energy Product: Germany-based offshore wind installation company. References: VWind AG1 This...

  15. Energy Alliance | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Alliance Jump to: navigation, search Name: Energy Alliance Place: Freiburg, Germany Zip: 79110 Sector: Solar Product: Germany-based, research group at the Fraunhofer Institute for...

  16. Wiesenhof | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Wiesenhof Jump to: navigation, search Name: Wiesenhof Place: Germany Product: Germany-based PHW Group company, is local poultry company. References: Wiesenhof1 This article is a...

  17. AFTER A Framework for electrical power sysTems vulnerability...

    OpenEI (Open Energy Information) [EERE & EIA]

    Germany) Jump to: navigation, search Project Name AFTER A Framework for electrical power sysTems vulnerability identification, dEfense and Restoration Country Germany Coordinates...

  18. Interstrom AG | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    AG Jump to: navigation, search Name: Interstrom AG Place: Bayreuth, Bavaria, Germany Zip: 95448 Sector: Solar Product: Germany-based electricity provider. The firm is...

  19. SolarHybrid AG | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    SolarHybrid AG Jump to: navigation, search Name: SolarHybrid AG Place: Germany Sector: Solar Product: Germany-based solar thermal hybrid product manufacturer References:...

  20. Chorus Systems | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Chorus Systems Jump to: navigation, search Name: Chorus Systems Place: Sankt Augustin, Germany Zip: D-53757 Product: Plans and realises PV installations in Germany. References:...

  1. Geothermeon | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    navigation, search Name: Geothermeon Place: Landau i.d. Pfalz, Rhineland-Palatinate, Germany Zip: 76829 Sector: Geothermal energy Product: Germany-based geothermal project...

  2. Solare AG | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    AG Jump to: navigation, search Name: Solare AG Place: Cologne, North Rhine-Westphalia, Germany Zip: 50678 Sector: Solar Product: Germany-based equipment manufacturer and developer...

  3. BIOGRAPHICAL SKETCH

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    (865) 241-5470 balken@ornl.gov Publication Education Technical University Darmstadt, Germany Materials Science Diploma, 2003 Technical University Darmstadt, Germany Materials...

  4. SVAROS Ventures | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Ventures Jump to: navigation, search Name: SVAROS Ventures Place: Munich, Bavaria, Germany Product: Germany-based VCgrowth capital investor in clean technology and technology...

  5. AE Photonics | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Photonics Jump to: navigation, search Name: AE Photonics Place: Germany Product: Germany-based PV system and component supplier References: AE Photonics1 This article is a stub....

  6. RWE Innogy | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Innogy Jump to: navigation, search Name: RWE Innogy Place: Essen, Germany Zip: 45141 Sector: Renewable Energy Product: Germany-based subsidiary of RWE responsible for RWE's...

  7. Vento Ludens | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Ludens Jump to: navigation, search Name: Vento Ludens Place: Jettingen-Scheppach, Germany Zip: 89343 Sector: Wind energy Product: Vento Ludens is a Germany based wind project...

  8. Landwind GmbH | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    GmbH Jump to: navigation, search Name: Landwind GmbH Place: Gevensleben, Lower Saxony, Germany Zip: 38384 Product: Small project developer, focused in Lower Saxony, Germany....

  9. WK Windkraft Kontor | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Kontor Jump to: navigation, search Name: WK Windkraft-Kontor Place: Grebenstein, Germany Zip: D-34393 Sector: Wind energy Product: Germany-based wind energy project...

  10. Sunselex | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Sunselex Jump to: navigation, search Name: Sunselex Place: Munchen, Bavaria, Germany Zip: D-81829 Sector: Solar Product: Germany based provider in the area of assembly and...

  11. HAASE Energietechnik Group | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Group Jump to: navigation, search Name: HAASE Energietechnik Group Place: Neumuenster, Germany Zip: D-24531 Product: Germany-based, environmental engineering and plant construction...

  12. Nordex | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    search Logo: Nordex Name: Nordex Address: Langenhorner Chaussee 600 22419 Hamburg Germany Place: Hamburg, Germany Sector: Wind energy Product: Wind Turbines Year Founded: 1992...

  13. Offshore Wind Technologie GmbH OWT | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Jump to: navigation, search Name: Offshore Wind Technologie GmbH (OWT) Place: Leer, Germany Zip: 26789 Sector: Wind energy Product: Germany-based wind project developer....

  14. Formaro GmbH | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Jump to: navigation, search Name: Formaro GmbH Place: Netphen, North Rhine-Westphalia, Germany Zip: 57250 Sector: Renewable Energy, Solar Product: Germany-based renewable energy...

  15. Hansatronic GmbH | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    search Name: Hansatronic GmbH Place: Villingen-Schwenningen, Baden-Wrttemberg, Germany Zip: 78052 Product: Germany-based manufacturer of PV connectors and junction boxes....

  16. Enovos Group | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Enovos Group Jump to: navigation, search Name: Enovos Group Place: Germany Sector: Solar Product: Germany-based utility. The utility has interests in solar energy. References:...

  17. European Business School | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Jump to: navigation, search Name: European Business School Place: Oestrich-Winkel, Germany Zip: D-65375 Sector: Efficiency Product: An Germany-based business school focusing on...

  18. Compel Electronics GmbH | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Electronics GmbH Jump to: navigation, search Name: Compel Electronics GmbH Place: Germany Product: Germany-based manufacturer of electronic cables and interconnections. The...

  19. Desertec Foundation | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Foundation Jump to: navigation, search Name: Desertec Foundation Place: Munchen, Germany Zip: 80802 Product: String representation "Germany-based D ... ial Initiative." is...

  20. Freund | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Freund Jump to: navigation, search Name: Freund Place: Germany Sector: Wind energy Product: Freund owns three wind turbines in Neu Zauche, Germany. References: Freund1 This...

  1. In Trust AG | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Trust AG Jump to: navigation, search Name: in-Trust AG Place: Regensburg, Bavaria, Germany Zip: 93047 Product: Germany-based investment company focused mainly on investing in...

  2. EBITSCHenergietechnik | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    EBITSCHenergietechnik Jump to: navigation, search Name: EBITSCHenergietechnik Place: Germany Sector: Renewable Energy Product: Germany-based firm that offers tailor-made economic...

  3. Altus AG | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Altus AG Jump to: navigation, search Name: Altus AG Place: Germany Sector: Renewable Energy Product: Germany-based renewable energy project developer. References: Altus AG1 This...

  4. MaxxContact | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Jump to: navigation, search Name: MaxxContact Place: Wolfen, Saxony-Anhalt, Germany Zip: 6766 Product: Germany-based cable and wire company. The firm also produces...

  5. Jura Energija | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Energija Jump to: navigation, search Name: Jura Energija Place: Germany Sector: Wind energy Product: German company active in developing wind farms in Germany, Croatia and Greece....

  6. Jacob GmbH Elektrotechnische Fabrik | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Jump to: navigation, search Name: Jacob GmbH Elektrotechnische Fabrik Place: Kernen, Germany Zip: 71394 Product: Germany-based manufacturer of cable glands. The firm also...

  7. Stadtwerke Mainz AG | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Mainz AG Jump to: navigation, search Name: Stadtwerke Mainz AG Place: Mainz, Germany Zip: 55118 Product: Utility in Mainz, Germany. References: Stadtwerke Mainz AG1 This article...

  8. Hochtief | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Hochtief Jump to: navigation, search Name: Hochtief Place: Essen, Germany Zip: 45128 Product: A global construction group based in Germany. Coordinates: 51.451805, 7.010625...

  9. BASF Linde Group JV | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Linde Group JV Jump to: navigation, search Name: BASF & Linde Group JV Place: Germany Sector: Carbon Product: Germany-based carbon capture projects joint venture. References: BASF...

  10. Phoenix Contact Gmbh | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Jump to: navigation, search Name: Phoenix Contact Gmbh Place: Blomberg, Lower Saxony, Germany Zip: 32825 Product: Germany-based firm in electrical connection, interface and...

  11. Edinastur | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Edinastur Jump to: navigation, search Name: Edinastur Place: Germany Sector: Wind energy Product: Wind Farm developer in Germany. References: Edinastur1 This article is a stub....

  12. BIOHAUS PV Handels GmbH | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    GmbH Jump to: navigation, search Name: BIOHAUS PV Handels GmbH Place: Paderborn, Germany Zip: 33100 Product: Distributor of Isofoton PV products in Germany. Coordinates:...

  13. SolarWorld AG | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    SolarWorld AG Jump to: navigation, search Name: SolarWorld AG Place: Bonn, Germany Zip: 53113 Product: Vertically integrated PV manufacturer, with factories in Freiberg, Germany...

  14. Enbion | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Enbion Jump to: navigation, search Name: Enbion Place: Germany Sector: Solar Product: Germany-based biogas and solar project developer. References: Enbion1 This article is a...

  15. RWE Solutions | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    RWE Solutions Place: Neu-Isenburg, Germany Zip: 63263 Sector: Solar Product: Germany-based, subsidiary of RWE AG plans, builds and manages energy infrastructure for utilities...

  16. Solea AG | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    AG Jump to: navigation, search Name: Solea AG Place: Plattling, Germany Zip: 94447 Product: A Germany PV project developer and building contractor, who also manufactures its own...

  17. Geysir Europe | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Geysir Europe Jump to: navigation, search Name: Geysir Europe Place: Germany Sector: Geothermal energy Product: Germany-based European subsidiary of Geysir Green Energy focusing on...

  18. ADAPT Elektronik GmbH | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    GmbH Jump to: navigation, search Name: ADAPT Elektronik GmbH Place: Grobheubach, Germany Zip: 63920 Sector: Solar Product: Germany-based manufacturer of electronic connector...

  19. Colexon Energy | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Energy Jump to: navigation, search Name: Colexon Energy Place: Hamburg, Hamburg, Germany Zip: 20354 Sector: Solar, Wind energy Product: Germany-based PV system integrator and solar...

  20. AMB Apparate Maschinenbau GmbH | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Jump to: navigation, search Name: AMB Apparate + Maschinenbau GmbH Place: Langweid, Germany Zip: 86462 Sector: Solar Product: Germany-based firm that offers automation...

  1. Energy Technology Centre | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Centre Jump to: navigation, search Name: Energy Technology Centre Place: Nuremberg, Germany Zip: 90443 Sector: Solar Product: Germany-based incubator and research housing facility,...

  2. Verbio | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Verbio Jump to: navigation, search Name: Verbio Place: Zrbig, Saxony-Anhalt, Germany Zip: 6780 Product: Germany-based producer and marketer of biodiesel and bioethanol....

  3. Schoeller Renewables | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Schoeller Renewables Jump to: navigation, search Name: Schoeller Renewables Place: Germany Sector: Solar, Wind energy Product: Germany-based subsidiary of Schoeller Industries that...

  4. EDeMa (Smart Grid Project) | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Jump to: navigation, search Project Name EDeMa Country Germany Headquarters Location Mlheim, Germany Coordinates 51.427074, 6.886492 Loading map... "minzoom":false,"mapping...

  5. Envisolar | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Envisolar Jump to: navigation, search Name: Envisolar Place: Saxony-Anhalt, Germany Zip: D-82230 Weling Sector: Solar Product: Germany-based resource forecasting consultant,...

  6. Etelligence (Smart Grid Project) | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    (Smart Grid Project) Jump to: navigation, search Project Name Etelligence Country Germany Headquarters Location Oldenburg, Germany Coordinates 53.136719, 8.216536 Loading...

  7. ENRO Energie | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Energie Jump to: navigation, search Name: ENRO Energie Place: Essen, Germany Zip: 45128 Sector: Geothermal energy Product: Germany-based company engaged in the design and...

  8. Maka Windkraft GmbH | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Windkraft GmbH Jump to: navigation, search Name: Maka Windkraft GmbH Place: 33034, Germany Sector: Wind energy Product: Wind farm developer in Germany References: Maka...

  9. WALTER Konzept | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    WALTER Konzept Jump to: navigation, search Name: WALTER Konzept Place: Ellwangen, Germany Zip: 73479 Sector: Solar Product: Germany-based project management and architecture firm....

  10. Fisia Babcock Environment GmbH | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Germany Zip: D-51643 Product: Germany-based engineering and construction firm of plants for thermal waste treatment and fuel gas cleaning plants. References: Fisia Babcock...

  11. Green GECCO | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    GECCO Jump to: navigation, search Name: Green GECCO Place: Germany Sector: Renewable Energy Product: Germany-based joint venture to develop renewable energy projects. References:...

  12. European Business Council for Sustainable Energy e5 | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    Council for Sustainable Energy e5 Jump to: navigation, search Name: European Business Council for Sustainable Energy (e5) Place: Karben, Germany Product: Germany-based, initiative...

  13. ACI ecotec GmbH | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Thuringia, Germany Zip: 78658 Product: Germany-based PV equipment design and manufacturing company. Coordinates: 51.007519, 11.626786 Show Map Loading map......

  14. Centrotherm SiTec GmbH | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Germany Product: Germany-based subsidiary of Centrotherm. The unit provides turnkey manufacturing equipment for polysilicon factory. References: Centrotherm SiTec GmbH1 This...

  15. Eon Masdar Integrated Carbon | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Eon Masdar Integrated Carbon Jump to: navigation, search Name: Eon Masdar Integrated Carbon Place: Germany Sector: Carbon Product: Germany-based carbon emission projects developer....

  16. Buschel Connecting Systems GmbH BCS | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    (BCS) Place: Jungingen, Baden-Wrttemberg, Germany Zip: 72417 Product: Germany-based firm developing, producing and selling electrical plug connecting systems. The firm also...

  17. CH2 Contorhaus Hansestadt Hamburg | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Germany Zip: 20457 Sector: Solar Product: Germany-based firm that sets up closed-end funds for investor-capital market products and projects, including solar. Coordinates:...

  18. PV Strom | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Place: Kirchheim, Germany Zip: 74366 Sector: Biomass, Hydro, Renewable Energy, Solar, Wind energy Product: Germany-based renewable energy project developer, focused mainly on...

  19. GATE Global Alternative Energy Holding AG | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Energy Holding AG Place: Wrzburg, Bavaria, Germany Zip: 97080 Product: Germany-based biodiesel producer. References: GATE Global Alternative Energy Holding AG1 This article...

  20. Pegasus Energietechnik AG | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    AG Place: Mhldorf am Inn, Germany Zip: 84453 Sector: Renewable Energy Product: Germany-based renewable energy developer assisting with projects in Europe. References:...

  1. European Energy Exchange AG EEX | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Energy Exchange AG EEX Jump to: navigation, search Name: European Energy Exchange AG (EEX) Place: Leipzig, Germany Zip: D-04109 Product: Germany's energy exchange, which aims to...

  2. Absolute radiant power measurement for the Au M lines of laser...

    Office of Scientific and Technical Information (OSTI)

    (Germany) Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin (Germany) Publication Date: 2014-01-15 OSTI Identifier: 22251206 Resource Type: Journal...

  3. Clean Urban Transport for Europe CUTE | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Transport for Europe CUTE Jump to: navigation, search Name: Clean Urban Transport for Europe (CUTE) Place: Ulm, Germany Zip: 89077 Product: Germany-based, European Union project...

  4. Union zur F rderung von Oel und Proteinpflanzen Ufop | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    zur F rderung von Oel und Proteinpflanzen Ufop Jump to: navigation, search Name: Union zur Frderung von Oel- und Proteinpflanzen (Ufop) Place: Germany Product: Germany-based...

  5. GEE Energy GmbH Co KG | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Place: Hamburg, Germany Zip: 20459 Sector: Biomass Product: Biomass trader delivering wood pellets, wood and bark briquettes to Germany, Scandinavia, Austria, Italy and...

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

    Energy.gov [DOE]

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

  7. Jackson Megiatto | Center for Bio-Inspired Solar Fuel Production

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Barun Das Bhupesh Goyal Jackson Megiatto Lu Gan Matthieu Koepf Matthieu Walther Sandip Shinde Sudhanshu Sharma Jackson Megiatto Postdoctoral Fellow Subtask 4 project: "Design and Synthesis of Artificial Reaction Centers for Artificial Photoelectrochemical Devices"

  8. Infrastructure Security EXCEPTIONAL SERVICE IN THE NATIONAL INTEREST

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    GaN for LED Lighting Displays and High Power Electronics The LED market is one of the fastest growing worldwide, driven by demand for clean solid state lighting, LED displays, and ...

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

    DOE PAGES [OSTI]

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

    2016-04-13

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

  10. A High Temperature-Tolerant and Radiation-Resistant In-Core Neutron Sensor for Advanced Reactors. Final report

    SciTech Connect

    Cao, Lei; Miller, Don

    2015-01-23

    The objectives of this project are to develop a small and reliable gallium nitride (GaN) neutron sensor that is capable of withstanding high neutron fluence and high temperature, isolating gamma background, and operating in a wide dynamic range. The first objective will be the understanding of the fundamental materials properties and electronic response of a GaN semiconductor materials and device in an environment of high temperature and intense neutron field. To achieve such goal, an in-situ study of electronic properties of GaN device such as I-V, leakage current, and charge collection efficiency (CCE) in high temperature using an external neutron beam will be designed and implemented. We will also perform in-core irradiation of GaN up to the highest yet fast neutron fluence and an off-line performance evaluation.

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

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

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

  12. Search for: All records | DOE PAGES

    Office of Scientific and Technical Information (OSTI)

    Gan, Chee Lip (1) Schuh, Christopher A. (1) Tamura, Nobumichi (1) Zeng, Xiao Mei (1) Save Results Excel (limit 2000) CSV (limit 5000) XML (limit 5000) Have feedback or suggestions ...

  13. ARM - Data Announcements Article

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    October 8, 2014 Data Announcements Large-Scale Forcing Data for AMIE-GAN Updated Bookmark and Share Analysis domain for Revelle, with diameters of 300 km. The red star denotes ...

  14. ARM - Data Announcements Article

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    August 19, 2013 Data Announcements Large-Scale Forcing Data for AMIE-Gan Available for Evaluation Bookmark and Share Large-scale forcing data from the SMART-R precipitation radar ...

  15. Opportunities for Wide Bandgap Semiconductor Power Electronics...

    Energy.gov [DOE] (indexed site)

    Semiconductor Power Electronics for Hydrogen and Fuel Cell Applications" held on October 21, 2014. ... Vehicle Technologies Office Merit Review 2016: Advanced Low-Cost SiC and GaN Wide ...

  16. Soraa Is Optimizing the Use of Non-Polar and Semi-Polar Substrates...

    Energy Saver

    on low defect density native GaN substrate instead of the conventional approach of growing heteroepitaxially (i.e., on substrates such as sapphire, silicon carbide, or silicon). ...

  17. 2016 Project Portfolio: Solid-State Lighting

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    ... Throughput, High Precision Hot Testing Tool for HBLED ... 25 Improved Light Extraction from GaN LEDs (Phase I) ... of Droop Mechanism in GaN-Based Light Emitting Diodes ...

  18. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    ... Filter Results Filter by Subject materials science (5) crystal growth (3) indium arsenides ... Corresponding full PIN structures have been realized by growing a p-type GaN layer on the ...

  19. fgr3372.tmp

    Office of Scientific and Technical Information (OSTI)

    ... of Science, Office of Basic Energy Science, Division of Materials Sciences of the ... GaN, a wide direct bandgap semiconductor, and its alloys with AIN and InN, have realized, ...

  20. Webinar October 21: Opportunities for Wide Bandgap Semiconductor...

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    from the development of next-generation power electronics based on wide bandgap (WBG) semiconductor materials such as SiC and GaN. Examples include the development of reliable,...