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Sample records for mobile facility gan

  1. Mobile Facility

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

    govSitesMobile Facility AMF Information Science Architecture Baseline Instruments AMF1 AMF2 AMF3 MAOS AMF Fact Sheet Images Contacts AMF Deployments McMurdo Station, Antarctica, 2015-2016 Pearl Harbor, Hawaii, to San Francisco, California, 2015 Hyytiälä, Finland, 2014 Manacapuru, Brazil, 2014 Oliktok Point, Alaska, 2013 Los Angeles, California, to Honolulu, Hawaii, 2012 Cape Cod, Massachusetts, 2012 Gan Island, Maldives, 2011 Ganges Valley, India, 2011 Steamboat Springs, Colorado, 2010

  2. ARM Mobile Facilities

    SciTech Connect (OSTI)

    Orr, Brad; Coulter, Rich

    2010-12-13

    This video provides an overview of the ARM Mobile Facilities, two portable climate laboratories that can deploy anywhere in the world for campaigns of at least six months.

  3. ARM Mobile Facilities

    ScienceCinema (OSTI)

    Orr, Brad; Coulter, Rich

    2014-09-15

    This video provides an overview of the ARM Mobile Facilities, two portable climate laboratories that can deploy anywhere in the world for campaigns of at least six months.

  4. ARM - ARM Mobile Facility 1 Article

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

    CenterARM Mobile Facility 1ARM Mobile Facility 1 Article Media Contact Hanna Goss hanna-dot-goss-at-pnnl-dot-gov @armnewsteam Field Notes Blog Topics Field Notes118 AGU 3 AMIE 10 ARM Aerial Facility 2 ARM Mobile Facility 1 7 ARM Mobile Facility 2 47 ARM Mobile Facility 3 1 BAECC 1 BBOP 4 CARES 1 Data Quality Office 2 ENA 2 GOAMAZON 7 HI-SCALE 5 LASIC 3 MAGIC 15 MC3E 17 PECAN 3 SGP 8 STORMVEX 29 TCAP 3 Search News Search Blog News Center All Categories What's this? Social Media Guidance News

  5. ARM Operations and Engineering Procedure Mobile Facility Site...

    Office of Scientific and Technical Information (OSTI)

    ARM Operations and Engineering Procedure Mobile Facility Site Startup Citation Details In-Document Search Title: ARM Operations and Engineering Procedure Mobile Facility Site Startup ...

  6. 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

  7. Deployment of ARM Aerial Facility (AAF) Scanning Mobility Particle...

    Office of Scientific and Technical Information (OSTI)

    Mobility Particle Sizer Field Campaign Report Citation Details In-Document Search Title: Deployment of ARM Aerial Facility (AAF) Scanning Mobility Particle Sizer Field ...

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

    SciTech Connect (OSTI)

    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.

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

    DOE PAGES-Beta [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

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

    SciTech Connect (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.; 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.

  11. ARM Mobile Facility - Design and Schedule for Integration

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

    Mobile Facility - Design and Schedule for Integration K. B. Widener Pacific Northwest ... The design phase for developing the AMF has begun. A design review was held for the AMF in ...

  12. Mobile Facility Records Annual Climate Cycle in Niger, Africa

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

    Mobile Facility Records Annual Climate Cycle in Niger, Africa Because dust can block ... These data are being used by scientists to study the nature of dust storms, how far they ...

  13. ARM - Field Campaign - Application of the ARM Mobile Facility...

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

    the ARM Mobile Facility (AMF) to Study the Aerosol Indirect Effects in China Campaign Links China Website ARM Data Discovery Browse Data Comments? We would love to hear from you ...

  14. Deployment of ARM Aerial Facility (AAF) Scanning Mobility Particle Sizer

    Office of Scientific and Technical Information (OSTI)

    Field Campaign Report (Technical Report) | SciTech Connect Deployment of ARM Aerial Facility (AAF) Scanning Mobility Particle Sizer Field Campaign Report Citation Details In-Document Search Title: Deployment of ARM Aerial Facility (AAF) Scanning Mobility Particle Sizer Field Campaign Report Atmospheric aerosols influence global climate by scattering and absorbing sunlight (direct effects) and by changing the microphysical structure, lifetime, and coverage of clouds (indirect effects). While

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

    SciTech Connect (OSTI)

    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.

  16. ARM Operations and Engineering Procedure Mobile Facility Site Startup

    SciTech Connect (OSTI)

    Voyles, Jimmy W

    2015-05-01

    This procedure exists to define the key milestones, necessary steps, and process rules required to commission and operate an Atmospheric Radiation Measurement (ARM) Mobile Facility (AMF), with a specific focus toward on-time product delivery to the ARM Data Archive. The overall objective is to have the physical infrastructure, networking and communications, and instrument calibration, grooming, and alignment (CG&A) completed with data products available from the ARM Data Archive by the Operational Start Date milestone.

  17. ARM Mobile Facility Surface Meteorology Handbook - October 2008

    SciTech Connect (OSTI)

    MT Ritsche

    2008-10-30

    The ARM Mobile Facility Surface Meteorology station (AMF MET) uses mainly conventional in situ sensors to obtain 1-minute statistics of surface wind speed, wind direction, air temperature, relative humidity, barometric pressure, and rain-rate. Additional sensors may be added to or removed from the base set of sensors depending upon the deployment location, climate regime or programmatic needs. Additionally, sensor types may change depending upon the climate regime of the deployment. These changes/additions are noted in the Deployment Locations and History section.

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

    SciTech Connect (OSTI)

    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

  19. Use of ARM Mobile Facility (AMF) Data to Study Aerosol Indirect Effects in China

    SciTech Connect (OSTI)

    Li, Zhanqing

    2012-12-19

    General goals: 1) Facilitating the deployment of the ARM Mobile Facility (AMF) and Ancillary Facility (AAF) in China in 2008, 2) Processing, retrieving, improving and analyzing observation data from ground-based, air-borne and space-borne instruments; 3) Conducting a series of studies to gain insights into the direct and indirect effects of these aerosols on radiation, clouds, and precipitation using both

  20. Mobile Pit verification system design based on passive special nuclear material verification in weapons storage facilities

    SciTech Connect (OSTI)

    Paul, J. N.; Chin, M. R.; Sjoden, G. E.

    2013-07-01

    A mobile 'drive by' passive radiation detection system to be applied in special nuclear materials (SNM) storage facilities for validation and compliance purposes has been designed through the use of computational modeling and new radiation detection methods. This project was the result of work over a 1 year period to create optimal design specifications to include creation of 3D models using both Monte Carlo and deterministic codes to characterize the gamma and neutron leakage out each surface of SNM-bearing canisters. Results were compared and agreement was demonstrated between both models. Container leakages were then used to determine the expected reaction rates using transport theory in the detectors when placed at varying distances from the can. A 'typical' background signature was incorporated to determine the minimum signatures versus the probability of detection to evaluate moving source protocols with collimation. This established the criteria for verification of source presence and time gating at a given vehicle speed. New methods for the passive detection of SNM were employed and shown to give reliable identification of age and material for highly enriched uranium (HEU) and weapons grade plutonium (WGPu). The finalized 'Mobile Pit Verification System' (MPVS) design demonstrated that a 'drive-by' detection system, collimated and operating at nominally 2 mph, is capable of rapidly verifying each and every weapon pit stored in regularly spaced, shelved storage containers, using completely passive gamma and neutron signatures for HEU and WGPu. This system is ready for real evaluation to demonstrate passive total material accountability in storage facilities. (authors)

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

    SciTech Connect (OSTI)

    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.

  2. Clouds, aerosol, and precipitation in the Marine Boundary Layer: An ARM mobile facility deployment

    DOE PAGES-Beta [OSTI]

    Wood, Robert; Luke, Ed; Wyant, Matthew; Bretherton, Christopher S.; Remillard, Jasmine; Kollias, Pavlos; Fletcher, Jennifer; Stemmler, Jayson; deSzoeke, S.; Yuter, Sandra; et al

    2014-04-27

    The Clouds, Aerosol, and Precipitation in the Marine Boundary Layer (CAP-MBL) deployment at Graciosa Island in the Azores generated a 21-month (April 2009-December 2010) comprehensive dataset documenting clouds, aerosols, and precipitation using the Atmospheric Radiation Measurement Program (ARM) Mobile Facility (AMF). The scientific aim of the deployment is to gain improved understanding of the interactions of clouds, aerosols, and precipitation in the marine boundary layer. Graciosa Island straddles the boundary between the subtropics and midlatitudes in the Northeast Atlantic Ocean and consequently experiences a great diversity of meteorological and cloudiness conditions. Low clouds are the dominant cloud type, with stratocumulusmore » and cumulus occurring regularly. Approximately half of all clouds contained precipitation detectable as radar echoes below the cloud base. Radar and satellite observations show that clouds with tops from 1-11 km contribute more or less equally to surface-measured precipitation at Graciosa. A wide range of aerosol conditions was sampled during the deployment consistent with the diversity of sources as indicated by back-trajectory analysis. Preliminary findings suggest important two-way interactions between aerosols and clouds at Graciosa, with aerosols affecting light precipitation and cloud radiative properties while being controlled in part by precipitation scavenging.The data from Graciosa are being compared with short-range forecasts made with a variety of models. A pilot analysis with two climate and two weather forecast models shows that they reproduce the observed time-varying vertical structure of lower-tropospheric cloud fairly well but the cloud-nucleating aerosol concentrations less well. The Graciosa site has been chosen to be a permanent fixed ARM site that became operational in October 2013.« less

  3. Clouds, Aerosols, and Precipitation in the Marine Boundary Layer: An Arm Mobile Facility Deployment

    SciTech Connect (OSTI)

    Wood, Robert; Wyant, Matthew; Bretherton, Christopher S.; Rémillard, Jasmine; Kollias, Pavlos; Fletcher, Jennifer; Stemmler, Jayson; de Szoeke, Simone; Yuter, Sandra; Miller, Matthew; Mechem, David; Tselioudis, George; Chiu, J. Christine; Mann, Julian A. L.; O’Connor, Ewan J.; Hogan, Robin J.; Dong, Xiquan; Miller, Mark; Ghate, Virendra; Jefferson, Anne; Min, Qilong; Minnis, Patrick; Palikonda, Rabindra; Albrecht, Bruce; Luke, Ed; Hannay, Cecile; Lin, Yanluan

    2015-03-01

    The Clouds, Aerosol, and Precipitation in the Marine Boundary Layer (CAP-MBL) 38 deployment at Graciosa Island in the Azores generated a 21 month (April 2009-December 2010) 39 comprehensive dataset documenting clouds, aerosols and precipitation using the Atmospheric 40 Radiation Measurement (ARM) Mobile Facility (AMF). The scientific aim of the deployment is 41 to gain improved understanding of the interactions of clouds, aerosols and precipitation in the 42 marine boundary layer. 43 Graciosa Island straddles the boundary between the subtropics and midlatitudes in the 44 Northeast Atlantic Ocean, and consequently experiences a great diversity of meteorological and 45 cloudiness conditions. Low clouds are the dominant cloud type, with stratocumulus and cumulus 46 occurring regularly. Approximately half of all clouds contained precipitation detectable as radar 47 echoes below the cloud base. Radar and satellite observations show that clouds with tops from 1-48 11 km contribute more or less equally to surface-measured precipitation at Graciosa. A wide 49 range of aerosol conditions was sampled during the deployment consistent with the diversity of 50 sources as indicated by back trajectory analysis. Preliminary findings suggest important two-way 51 interactions between aerosols and clouds at Graciosa, with aerosols affecting light precipitation 52 and cloud radiative properties while being controlled in part by precipitation scavenging. 53 The data from at Graciosa are being compared with short-range forecasts made a variety 54 of models. A pilot analysis with two climate and two weather forecast models shows that they 55 reproduce the observed time-varying vertical structure of lower-tropospheric cloud fairly well, 56 but the cloud-nucleating aerosol concentrations less well. The Graciosa site has been chosen to 57 be a long-term ARM site that became operational in October 2013.

  4. Clouds, aerosol, and precipitation in the Marine Boundary Layer: An ARM mobile facility deployment

    SciTech Connect (OSTI)

    Wood, Robert; Luke, Ed; Wyant, Matthew; Bretherton, Christopher S.; Remillard, Jasmine; Kollias, Pavlos; Fletcher, Jennifer; Stemmler, Jayson; deSzoeke, S.; Yuter, Sandra; Miller, Matthew; Mechem, David; Tselioudis, George; Chiu, Christine; Mann, Julia; O Connor, Ewan; Hogan, Robin; Dong, Xiquan; Miller, Mark; Ghate, Virendra; Jefferson, Anne; Min, Qilong; Minnis, Patrick; Palinkonda, Rabindra; Albrecht, Bruce; Hannay, Cecile; Lin, Yanluan

    2014-04-27

    The Clouds, Aerosol, and Precipitation in the Marine Boundary Layer (CAP-MBL) deployment at Graciosa Island in the Azores generated a 21-month (April 2009-December 2010) comprehensive dataset documenting clouds, aerosols, and precipitation using the Atmospheric Radiation Measurement Program (ARM) Mobile Facility (AMF). The scientific aim of the deployment is to gain improved understanding of the interactions of clouds, aerosols, and precipitation in the marine boundary layer. Graciosa Island straddles the boundary between the subtropics and midlatitudes in the Northeast Atlantic Ocean and consequently experiences a great diversity of meteorological and cloudiness conditions. Low clouds are the dominant cloud type, with stratocumulus and cumulus occurring regularly. Approximately half of all clouds contained precipitation detectable as radar echoes below the cloud base. Radar and satellite observations show that clouds with tops from 1-11 km contribute more or less equally to surface-measured precipitation at Graciosa. A wide range of aerosol conditions was sampled during the deployment consistent with the diversity of sources as indicated by back-trajectory analysis. Preliminary findings suggest important two-way interactions between aerosols and clouds at Graciosa, with aerosols affecting light precipitation and cloud radiative properties while being controlled in part by precipitation scavenging.The data from Graciosa are being compared with short-range forecasts made with a variety of models. A pilot analysis with two climate and two weather forecast models shows that they reproduce the observed time-varying vertical structure of lower-tropospheric cloud fairly well but the cloud-nucleating aerosol concentrations less well. The Graciosa site has been chosen to be a permanent fixed ARM site that became operational in October 2013.

  5. Facilities

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

    Facilities Facilities World-class facilities provide unique problem-solving opportunities. Unique research facilities support data-driven, agile solutions. Los Alamos National Laboratory has a number of facilities that support work related to sensor technologies and solutions including: Center for Integrated Nanotechnologies Dual-Axis Radiographic Hydrodynamic Test Facility The Explosives Center Lujan Neutron Scattering Center Materials Science Laboratory National High Magnetic Field Laboratory

  6. Facilities

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

    Nuclear Energy Defense Waste Management Programs Advanced Nuclear Energy Nuclear Energy Safety Technologies Facilities Battery Abuse Testing Laboratory Cylindrical Boiling Facility ...

  7. 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 ...

  8. ARM - Facility News Article

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

    of instruments collecting data for the ARM Mobile Facility field campaign at Point Reyes National Seashore. Since March 2005, the ARM Mobile Facility (AMF) has been at Point...

  9. ARM - Facility News Article

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

    a number of other guest instruments at the ARM Mobile Facility deployment site at Point Reyes National Seashore in California. The ARM Mobile Facility's (AMF's) inaugural field...

  10. ARM - Facility News Article

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

    Interferometers Compared for ARM Mobile Facility Deployment in China Bookmark and Share ... Mobile Facility in 2008 for a field campaign to study Aerosol Indirect Effects in China. ...

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

    SciTech Connect (OSTI)

    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.

  12. Facilities

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

    ... It also provides an outstanding controlled environment for Sandia's recent spent nuclear fuel combustion experiments. HPC Facilities CSRIBldghomepg The Computer Science Research ...

  13. Facilities

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

    First Power for SWiFT Turbine Achieved during Recommissioning Facilities, News, Renewable Energy, SWIFT, Wind Energy, Wind News First Power for SWiFT Turbine Achieved during ...

  14. ARM - Facility News Article

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

    December 4, 2010 [Facility News] Request for Proposals Now Open Bookmark and Share The ARM Climate Research Facility is now accepting applications for use of the ARM mobile facilities, aerial facility, and fixed sites. Proposals are welcome from all members of the scientific community for conducting field campaigns and scientific research using the ARM Facility. Facility availability is as follows: ARM Mobile Facility 2 (AMF2) available FY2013 ARM Mobile Facility 1 (AMF1) available March 2015

  15. ARM - Facility News Article

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

    20, 2010 Facility News ARM Mobile Facility Blogs from Steamboat Springs Bookmark and Share This month, team members for the second ARM Mobile Facility (AMF2) are in Steamboat...

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

    SciTech Connect (OSTI)

    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.

  17. 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

  18. ARM - Facility News Article

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

    the SGP site, and will begin in March for the ARM Mobile Facility deployment in Point Reyes, California. Launches for the ARM Climate Research Facility Tropical Western Pacific...

  19. ARM - Facility News Article

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

    January 11, 2007 Facility News ARM Mobile Facility Moves to China in 2008 for Study of ... China generates exceptionally high amounts of aerosol particles whose influence on the ...

  20. ARM - Facility News Article

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

    Data Available from ARM Mobile Facility Deployment in China Bookmark and Share The Study of Aerosol Indirect Effects in China was anchored by the ARM Mobile Facility in Shouxian ...

  1. AMF ARM Mobile FAcility

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

    at http:www.arm.govacrfsubmitproposals.stm. For more information, contact: Mark Miller Mary Jane Bartholomew AMF Site Scientist Assoc. Site Scientist (631) 344-2958 (631)...

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

    DOE PAGES-Beta [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.

  3. Facility Floorplan

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

    facility floorplan Facility Floorplan

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

    SciTech Connect (OSTI)

    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.

  5. Atmospheric Radiation Measurement Climate Research Facility Operations...

    Office of Scientific and Technical Information (OSTI)

    Title: Atmospheric Radiation Measurement Climate Research Facility Operations Quarterly ... Atmospheric Radiation Measurement (ARM) Climate Research Facility fixed and mobile sites ...

  6. Measurement of fenestration net energy performance: Considerations leading to development of a Mobile Window Thermal Test (MoWitt) facility

    SciTech Connect (OSTI)

    Klems, J.H.

    1988-08-01

    The authors present a detailed consideration of the energy flows entering a building space and the effect of random measurement errors on determining fenestration performance. Estimates of error magnitudes are made for a passive test cell; they show that a more accurate test facility is needed for reliable measurements on fenestration systems with thermal resistance 2-10 times that of single glazing or with shading coefficients less than 0.7. A test facility of this type, built at Lawrence Berkeley Laboratory, is described. The effect of random errors in this facility is discussed and computer calculations of its performance are presented. The discussion shows that, for any measurement facility, random errors are most serious in nighttime measurements, and systematic errors are most important in daytime measurements. It is concluded that, for this facility, errors from both sources should be small.

  7. 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

  8. ARM - Facility News Article

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

    about using the ARM in between sessions. Visitors to the booth were interested in learning about the latest ARM Mobile Facility deployment, the ongoing field campaign...

  9. ARM - Facility News Article

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

    From Coastal Clouds to Desert Dust: ARM Mobile Facility Headed to Africa Bookmark and ... international effort to study the effects of Saharan dust and the West African monsoons. ...

  10. ARM - Facility News Article

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

    ARM's two mobile facilities have completed field campaigns in the United States, Africa, Germany, the Azores, India, and the Maldives. They are currently preparing for yearlong...

  11. ARM - Facility News Article

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

    April 30, 2010 Data Announcements, Facility News Tandem Differential Mobility Analyzer (TDMA) Data Available at the ARM Data Archive Bookmark and Share Dry samples are collected...

  12. 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 ...

  13. 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) ...

  14. 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 ...

  15. ARM - Facility News Article

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

    triangles indicate ECMWF stations. New climate datastreams are now available from Point Reyes National Seashore in California, where the first deployment of the ARM Mobile Facility...

  16. ARM - Facility News Article

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

    of ARM Mobile Facility to Occur on California Coast Bookmark and Share Image - Point Reyes Beach Point Reyes National Seashore, on the California coast north of San Francisco,...

  17. ARM - Facility News Article

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

    Mixed-Phase Arctic Cloud Experiment, and the ARM Mobile Facility's deployments at Point Reyes National Seashore and Niamey, Niger, West Africa. ARM researchers, including ARM's...

  18. ARM - Facility News Article

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

    Mapping It Up With Google Bookmark and Share "Thumbtacks" help ARM website users identify where the ARM sites are, including the ARM Mobile Facility deployments. The online ARM...

  19. ARM - Facility News Article

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

    Begins Marine Cloud Study in the Azores Bookmark and Share Located next to the airport on Graciosa Island, the ARM Mobile Facility's comprehensive and sophisticated...

  20. ARM - Facility News Article

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

    Antarctica is the highest, driest, coldest, and windiest continent. It contains 90% of the ... which manages ARM mobile facilities and Eastern North Atlantic site in the Azores

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

    SciTech Connect (OSTI)

    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.

  2. ARM - Facility News Article

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

    March 22, 2007 Facility News GEWEX News Features Dust Data from ARM Mobile Facility ... The AMF recorded a major dust storm that passed through the area in March, and combined ...

  3. ARM - Facility News Article

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

    April 30, 2008 Facility News ARM Outreach Materials Chosen for Earth Day Display in Washington DC Bookmark and Share Posters for the ARM Mobile Facility and ARM Education and...

  4. ARM - Facility News Archive

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

    Archive Media Contact Hanna Goss hanna-dot-goss-at-pnnl-dot-gov @armnewsteam Field Notes Blog Topics Field Notes118 AGU 3 AMIE 10 ARM Aerial Facility 2 ARM Mobile Facility 1 7 ARM Mobile Facility 2 47 ARM Mobile Facility 3 1 BAECC 1 BBOP 4 CARES 1 Data Quality Office 2 ENA 2 GOAMAZON 7 HI-SCALE 5 LASIC 3 MAGIC 15 MC3E 17 PECAN 3 SGP 8 STORMVEX 29 TCAP 3 Search News Search Blog News Center All Categories What's this? Social Media Guidance News Center All Categories Features and Releases Facility

  5. ARM - Facility News

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

    News Media Contact Hanna Goss hanna-dot-goss-at-pnnl-dot-gov @armnewsteam Field Notes Blog Topics Field Notes118 AGU 3 AMIE 10 ARM Aerial Facility 2 ARM Mobile Facility 1 7 ARM Mobile Facility 2 47 ARM Mobile Facility 3 1 BAECC 1 BBOP 4 CARES 1 Data Quality Office 2 ENA 2 GOAMAZON 7 HI-SCALE 5 LASIC 3 MAGIC 15 MC3E 17 PECAN 3 SGP 8 STORMVEX 29 TCAP 3 Search News Search Blog News Center All Categories What's this? Social Media Guidance News Center All Categories Features and Releases Facility

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

    SciTech Connect (OSTI)

    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.

  7. GaN: Defect and Device Issues

    SciTech Connect (OSTI)

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

    1998-11-09

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

  8. GaN Initiative for Grid Applications (GIGA)

    SciTech Connect (OSTI)

    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

  9. ARM - Facility News Article

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

    22, 2011 [Facility News] Request for Proposals Now Open Bookmark and Share The ARM Climate Research Facility is now accepting applications for use of an ARM mobile facility (AMF), the ARM aerial facility (AAF), and fixed sites. Proposals are welcome from all members of the scientific community for conducting field campaigns and scientific research using the ARM Facility, with availability as follows: AMF2 available December 2013 AMF1 available March 2015 AAF available between June and October

  10. ARM - Facility News Article

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

    8, 2012 [Data Announcements, Facility News] New Data from Greenland for Arctic Climate Research Bookmark and Share Instruments for ICECAPS operate on top and inside of the Mobile Science Facility at Summit Station in Greenland. Instruments for ICECAPS operate on top and inside of the Mobile Science Facility at Summit Station in Greenland. In 2010, researchers installed a powerful suite of climate and weather instruments at Greenland's frozen research outpost, Summit Station, for a long-term

  11. 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...

  12. Integrating AlGaN/GaN high electron mobility transistor with Si: A comparative study of integration schemes

    SciTech Connect (OSTI)

    Mohan, Nagaboopathy; Raghavan, Srinivasan; Manikant,; Soman, Rohith

    2015-10-07

    AlGaN/GaN high electron mobility transistor stacks deposited on a single growth platform are used to compare the most common transition, AlN to GaN, schemes used for integrating GaN with Si. The efficiency of these transitions based on linearly graded, step graded, interlayer, and superlattice schemes on dislocation density reduction, stress management, surface roughness, and eventually mobility of the 2D-gas are evaluated. In a 500 nm GaN probe layer deposited, all of these transitions result in total transmission electron microscopy measured dislocations densities of 1 to 3 × 10{sup 9}/cm{sup 2} and <1 nm surface roughness. The 2-D electron gas channels formed at an AlGaN-1 nm AlN/GaN interface deposited on this GaN probe layer all have mobilities of 1600–1900 cm{sup 2}/V s at a carrier concentration of 0.7–0.9 × 10{sup 13}/cm{sup 2}. Compressive stress and changes in composition in GaN rich regions of the AlN-GaN transition are the most effective at reducing dislocation density. Amongst all the transitions studied the step graded transition is the one that helps to implement this feature of GaN integration in the simplest and most consistent manner.

  13. Windows and Building Envelope Facilities

    Energy.gov [DOE]

    LBNL’s has three facilities specifically dedicated to windows: the Optical Properties Laboratory, the Infrared Thermography Laboratory, and the Mobile Window Thermal Test Facility (MoWiTT). These...

  14. ARM - Facility News Article

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

    July 18, 2016 [Facility News] Next Round of Deadlines for Small Campaigns Coming Up Bookmark and Share The next deadline to propose for smaller field campaigns will be August 22. Small campaigns do not require a full deployment of ARM Facility equipment, like an ARM mobile or aerial facility. They require just an instrument or two, or are in conjunction with a larger facility operation. Costing less than $25,000, these campaigns give researchers access to ARM's equipment to perform focused,

  15. 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...

  16. ARM - Facility News Article

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

    Dust Using Data from Africa Bookmark and Share In 2006, the ARM Mobile Facility joined the AMMA project to obtain data for scientists to study the impact that airborne Saharan dust ...

  17. ARM - Facility News Article

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

    Preparations Underway for 2007 ARM Mobile Facility Deployment in Germany Bookmark and Share In the Black Forest region of Germany, the COPS field campaign will cover an area of ...

  18. ARM - Facility News Article

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

    the ARM Mobile Facility. ARM participated in the Student Exploration of Research in the Earth and Space Sciences (EXPRESS) program held on the last day of the 2005 AGU Fall...

  19. ARM - Facility News Article

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

    Mobile Facility Anchors Multi-site Aerosol Study in China Bookmark and Share The AMF ... data collection at four different sites for the Aerosol Indirect Effects Study in China. ...

  20. ARM - Facility News Article

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

    test period, plans are to deploy the new technology to both ARM Mobile Facilities and the Tropical Western Pacific sites in Darwin, Australia, and Manus Island, Papua New Guinea. ...

  1. ARM - Facility News Article

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

    and Share In January 2006, the ARM Mobile Facility (AMF) begins a year-long field campaign in Africa as part of a multi-year international experiment called the African...

  2. ARM - Facility News Article

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

    4, 2012 [Facility News] New Organization to Optimize ARM Radar Data Bookmark and Share Every ARM fixed and mobile site now includes both scanning (left) and zenith-pointing (right) cloud radars. The fixed sites also include scanning precipitation radars. Every ARM fixed and mobile site now includes both scanning (left) and zenith-pointing (right) cloud radars. The fixed sites also include scanning precipitation radars. In the past few years, the ARM Facility added 19 new scanning cloud and

  3. ARM - Facility News Article

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

    ARM's New Radar Operating Paradigm Aims to Maximize Performance Bookmark and Share Maintaining the pulse of the radar network is vital to research A Scanning ARM Cloud Radar is deployed with the ARM Mobile Facility on Antarctica for the ARM West Antarctic Radiation Experiment campaign. A Scanning ARM Cloud Radar is deployed with the ARM Mobile Facility on Antarctica for the ARM West Antarctic Radiation Experiment campaign. Radars have been getting a lot of attention at ARM in the last few

  4. High Voltage GaN Schottky Rectifiers

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    Zhang, Yu; Sun, Qian; Han, Jung

    2015-12-08

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

  6. Highly transparent ammonothermal bulk GaN substrates

    SciTech Connect (OSTI)

    Jiang, WK; Ehrentraut, D; Downey, BC; Kamber, DS; Pakalapati, RT; Do Yoo, H; D'Evelyn, MP

    2014-10-01

    A novel apparatus has been employed to grow ammonothermal (0001) gallium nitride (GaN) with diameters up to 2 in The crystals have been characterized by x-ray diffraction rocking-curve (XRC) analysis, optical and scanning electron microscopy (SEM), cathodoluminescence (CL), and optical spectroscopy. High crystallinity GaN with FWHM values about 20-50 arcsec and dislocation densities below 1 x 10(5) cm(-2) have been obtained. High optical transmission was achieved with an optical absorption coefficient below 1 cm(-1) at a wavelength of 450 nm. (C) 2014 Elsevier B.V. All rights reserved.

  7. Ferromagnetism in undoped One-dimensional GaN Nanowires

    SciTech Connect (OSTI)

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

    2014-05-15

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

  8. 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. ...

  9. Properties of H, O and C in GaN

    SciTech Connect (OSTI)

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

    1996-04-01

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

  10. Refractive index of erbium doped GaN thin films

    SciTech Connect (OSTI)

    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.

  11. Testing the effectiveness of mobile home weatherization measures in a controlled environment: The SERI CMFERT (Collaborative Manufactured Buildings Facility for Energy Research and Training) Project

    SciTech Connect (OSTI)

    Judkoff, R.D.; Hancock, C.E.; Franconi, E.

    1990-03-01

    For several years the Solar Energy Research Institute has been testing the effectiveness of mobile home weatherization measures, with the support of the US DOE Office of State and Local Assistance Programs Weatherization Assistance Program, the DOE Office of Buildings and Community Systems, the seven states within the federal Weatherization Region 7, the Colorado Division of Housing, and the DOE Denver Support Office. During the winter of 1988--89, several weatherization measures were thermally tested on three mobile homes under controlled conditions inside a large environmental enclosure. The effects of each weatherization measure on conduction losses, infiltration losses, and combined furnace and duct-delivered heat efficiency were monitored. The retrofit options included air sealing, duct repair, furnace tune-up, interior storm panels, floor insulation, and roof insulation. The study demonstrated that cost-effective heating energy savings of about 20% to 50% are possible if weatherization techniques adapted to the special construction details in mobile homes are applied. 24 refs., 18 figs., 9 tabs.

  12. Atmospheric Radiation Measurement Climate Research Facility ...

    Office of Scientific and Technical Information (OSTI)

    ARM Aerial Vehicles Program. * Successful deployment of the ARM Mobile Facility in Germany, including hosting nearly a dozen guest instruments and drawing almost 5000 visitors ...

  13. Structural defects in GaN revealed by Transmission Electron Microscopy

    DOE PAGES-Beta [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.

  14. Structural defects in GaN revealed by Transmission Electron Microscopy

    SciTech Connect (OSTI)

    Liliental-Weber, Zuzanna

    2014-04-18

    This paper reviews the various types of structural defects observed by Transmission Electron Microscopy in GaN heteroepitaxial layers grown on foreign substrates and homoepitaxial layers grown on bulk GaN substrates. The structural perfection of these layers is compared to the platelet self-standing crystals grown by High Nitrogen Pressure Solution. Defects in undoped and Mg doped GaN are discussed. Some models explaining the formation of inversion domains in heavily Mg doped layers that are possible defects responsible for the difficulties of p-doping in GaN are also reviewed.

  15. Dislocation core structures in Si-doped GaN

    SciTech Connect (OSTI)

    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. Laser Facilities

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

    Laser Facilities Current Schedule of Experiments Operation Schedule Janus Titan Europa COMET Facility Floorplan

  17. ARM - Facility News Article

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

    June 15, 2010 [Facility News] Up, Up, and Away-Automated Balloon Launcher Headed to North Slope Bookmark and Share The balloon-borne sounding system (BBSS) operates at ARM's three fixed sites and the ARM Mobile Facility. Sondes, launched into the air, provide information about the atmosphere's temperature, moisture, pressure, and wind speed. Performing regular balloon launches can be difficult, even dangerous, in the arctic climates of the North Slope of Alaska (NSA). But a new instrument system

  18. Nuclear Facilities Production Facilities

    National Nuclear Security Administration (NNSA)

    Facilities Production Facilities Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. Sand 2011-4582P. ENERGY U.S. DEPARTMENT OF Gamma Irradiation Facility (GIF) The GIF provides test cells for the irradiation of experiments with high-intensity gamma ray sources. The main features

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

    SciTech Connect (OSTI)

    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.

  20. Intelligent mobile security systems

    SciTech Connect (OSTI)

    Allen, M.S. )

    1991-01-01

    This paper reports that mobile security systems are becoming increasingly important to military (Army, Air Force) and non-military (Drug Enforcement Agency, Border Patrol) organizations as the level and sophistication of terrorist activity increases. Frequently, organizations are required to deploy at remote sites on little notice. To ensure protection of life and equipment, security systems are sometimes required. Often, the personnel deployed on these missions are not adequately trained in the selection, installation, and operation of today's complex security equipment. The Intelligent Mobile Security System (IMSS) concept, as being developed by Sandia National Laboratories (SNL), allows untrained, non-technical personnel to configure, deploy, operate, and troubleshoot temporary/mobile physical security system. The IMSS may be used at nuclear facilities.

  1. ARM - SGP Extended Facility

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

    Extended Facility SGP Related Links Virtual Tour Facilities and Instruments Central Facility Boundary Facility Extended Facility Intermediate Facility Radiometric Calibration...

  2. ARM - SGP Intermediate Facility

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

    Intermediate Facility SGP Related Links Virtual Tour Facilities and Instruments Central Facility Boundary Facility Extended Facility Intermediate Facility Radiometric Calibration...

  3. ARM - SGP Central Facility

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

    Central Facility SGP Related Links Virtual Tour Facilities and Instruments Central Facility Boundary Facility Extended Facility Intermediate Facility Radiometric Calibration...

  4. Data Management Facility Operations Plan

    SciTech Connect (OSTI)

    Keck, Nicole N

    2014-06-30

    The Data Management Facility (DMF) is the data center that houses several critical Atmospheric Radiation Measurement (ARM) Climate Research Facility services, including first-level data processing for the ARM Mobile Facilities (AMFs), Eastern North Atlantic (ENA), North Slope of Alaska (NSA), Southern Great Plains (SGP), and Tropical Western Pacific (TWP) sites, as well as Value-Added Product (VAP) processing, development systems, and other network services.

  5. Sandia Energy - Patent Awarded for the Fuel Cell Mobile Light

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

    Patent Awarded for the Fuel Cell Mobile Light Home Energy CRF Facilities Partnership News Energy Efficiency News & Events Systems Engineering Center for Infrastructure Research and...

  6. Huntington Resource Recovery Facility Biomass Facility | Open...

    Open Energy Information (Open El) [EERE & EIA]

    Resource Recovery Facility Biomass Facility Jump to: navigation, search Name Huntington Resource Recovery Facility Biomass Facility Facility Huntington Resource Recovery Facility...

  7. Wheelabrator Sherman Energy Facility Biomass Facility | Open...

    Open Energy Information (Open El) [EERE & EIA]

    Sherman Energy Facility Biomass Facility Jump to: navigation, search Name Wheelabrator Sherman Energy Facility Biomass Facility Facility Wheelabrator Sherman Energy Facility Sector...

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

    DOE Patents [OSTI]

    Zhang, Yu; Sun, Qian; Han, Jung

    2015-12-08

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

  9. 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...

  10. Ashton Extended Facility

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

    Ashton Extended Facility Map

  11. Byron Extended Facility

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

    Byron Extended Facility Map

  12. 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 ...

  13. 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 ...

  14. User Facilities

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

    User Facilities User Facilities User facility agreements allow Los Alamos partners and other entities to conduct research at our unique facilities. In 2011, LANL hosted more than 1,200 users at CINT, LANSCE, and NHMFL. Users came from across the DOE complex, from international academia, and from industrial companies from 45 states across the U.S. Unique world-class user facilities foster rich research opportunities Through its technology transfer efforts, LANL can implement user facility

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

    SciTech Connect (OSTI)

    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.

  16. 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:

  17. User Facilities

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

    Collaboration User Facilities collaborationassetsimagesicon-collaboration.jpg User Facilities A new research frontier awaits Our door is open and we thrive on mutually...

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

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    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.

  20. Intrinsic polarization control in rectangular GaN nanowire lasers

    DOE PAGES-Beta [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

  1. Size dictated thermal conductivity of GaN

    DOE PAGES-Beta [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

  2. ARM - Facility News Article

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

    10, 2010 [Facility News] Supporting Science at Summit Station, Greenland Bookmark and Share This month, an ARM micropulse lidar and ceilometer began collecting data from Summit Station in Greenland as part of the ICECAPS field campaign that runs through October 2014. Scientist Matthew Shupe joined colleagues on location to install the ICECAPS mobile laboratory, documenting their progress through his field blog. Great job, Matt! Visit the campaign website for more information

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

    SciTech Connect (OSTI)

    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.

  4. Facility Representatives

    Directives, Delegations, and Requirements [Office of Management (MA)]

    2011-03-01

    This standard, DOE-STD-1063, Facility Representatives, defines the duties, responsibilities and qualifications for Department of Energy (DOE) Facility Representatives, based on facility hazard classification; risks to workers, the public, and the environment; and the operational activity level. This standard provides the guidance necessary to ensure that DOE’s hazardous nuclear and non-nuclear facilities have sufficient staffing of technically qualified facility representatives (FRs) to provide day-to-day oversight of contractor operations.

  5. Evaluation of AlGaN/GaN high electron mobility transistors grown on ZrTi buffer layers with sapphire substrates

    DOE PAGES-Beta [OSTI]

    Ren, Fan; Pearton, Stephen J.; Ahn, Shihyun; Lin, Yi -Hsuan; Machuca, Francisco; Weiss, Robert; Welsh, Alex; McCartney, Martha R.; Smith, David J.; Kravchenko, Ivan I.

    2016-09-21

    Here, AlGaN/GaN high electron mobility transistors (HEMTs) have been grown on sapphire substrates, using ZrTi buffer layers to provide in-plane lattice-matching to hexagonal GaN. X-ray diffraction (XRD) as well as cross-section transmission electron microscopy (TEM) were used to assess the quality of the HEMT structure. The XRD 2θ scans showed full-width-at-half-maximum values of 0.16°, 0.07°, and 0.08° for ZrTi alloy, GaN buffer layer, and the entire HEMT structure, respectively. TEM studies of the GaN buffer layer and the AlN/ZrTi/AlN stack showed the importance of growing thin AlN buffer layers on the ZrTi layer prior to growth of the GaN buffermore » layer. The density of threading dislocations in the GaN channel layer of the HEMT structure was estimated to be in the 108 cm–2 range. The HEMT device exhibited a saturation drain current density of 820 mA/mm, and the channel of the fabricated HEMTs could be well modulated. A cutoff frequency (fT) of 8.9 GHz and a maximum frequency of oscillation (fmax) of 17.3 GHz were achieved for HEMTs with gate dimensions of 1 × 200 μm.« less

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

    SciTech Connect (OSTI)

    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

  7. ORISE: Facilities

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

    ORISE Facilities Unique laboratories and training centers among the assets managed on behalf of the U.S. Department of Energy The Oak Ridge Institute for Science and Education (ORISE) is home to a number of on- and off-site facilities that support the U.S. Department of Energy's (DOE) science education and research mission. From on-site medical laboratories to radiation emergency medicine training facilities, ORISE facilities are helping to address national needs in the following areas:

  8. Facility Safety

    Directives, Delegations, and Requirements [Office of Management (MA)]

    1996-10-24

    Establishes facility safety requirements related to: nuclear safety design, criticality safety, fire protection and natural phenomena hazards mitigation.

  9. Facility Safety

    Directives, Delegations, and Requirements [Office of Management (MA)]

    1995-11-16

    Establishes facility safety requirements related to: nuclear safety design, criticality safety, fire protection and natural phenomena hazards mitigation.

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

    SciTech Connect (OSTI)

    Kuppulingam, B. Singh, Shubra Baskar, K.

    2014-04-24

    Hexagonal Gallium Nitride (GaN) and Aluminum Gallium Nitride (AlGaN) nanoparticles were synthesized by sol-gel method using Ethylene Diamine Tetra Acetic acid (EDTA) complex route. Powder X-ray diffraction (PXRD) analysis confirms the hexagonal wurtzite structure of GaN and Al{sub 0.25}Ga{sub 0.75}N nanoparticles. Surface morphology and elemental analysis were carried out by Scanning Electron Microscope (SEM) and Energy Dispersive X-ray spectroscopy (EDX). The room temperature Photoluminescence (PL) study shows the near band edge emission for GaN at 3.35 eV and at 3.59 eV for AlGaN nanoparticles. The Aluminum (Al) composition of 20% has been obtained from PL emission around 345 nm.

  11. MOBILITY AGREEMENT

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

    MOBILITY AGREEMENT I hereby acknowledge that, as a condition of my employment as a Criminal Investigator with the Department of Energy, Office of Inspector General, I may be required to relocate to an OIG office in another geographic location based on the needs of the organization. I understand that my failure to accept such a directed reassignment could be a basis for my separation from the service. _______________________________ Signature Date

  12. Wheelabrator Millbury Facility Biomass Facility | Open Energy...

    Open Energy Information (Open El) [EERE & EIA]

    Facility Facility Wheelabrator Millbury Facility Sector Biomass Facility Type Municipal Solid Waste Location Worcester County, Massachusetts Coordinates 42.4096528, -71.8571331...

  13. Facility Representatives

    Energy Savers

    Program Manager Office of the Departmental Representative to the Defense Nuclear Facilities Safety Board (DOE DR-1) DOE Headquarters, Forrestal Building 1000 Independence ...

  14. Beamlines & Facilities

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

    Imaging Group: Beamlines The X-ray Micrscopy and Imaging Group operates several beamlines and facilities. The bending magnet beamline (2-BM) entertaines 2 general user programs in...

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

    SciTech Connect (OSTI)

    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.

  16. Facility Safety

    Directives, Delegations, and Requirements [Office of Management (MA)]

    2005-12-22

    This Order establishes facility and programmatic safety requirements for Department of Energy facilities, which includes nuclear and explosives safety design criteria, fire protection, criticality safety, natural phenomena hazards mitigation, and the System Engineer Program. Cancels DOE O 420.1A. DOE O 420.1B Chg 1 issued 4-19-10.

  17. Facility Representatives

    Directives, Delegations, and Requirements [Office of Management (MA)]

    2006-04-06

    REPLACED BY DOE-STD-1063 | SUPERSEDING DOE-STD-1063-2000 (MARCH 2000) The purpose of the DOE Facility Representative Program is to ensure that competent DOE staff personnel are assigned to oversee the day-to-day contractor operations at DOE’s hazardous nuclear and non-nuclear facilities.

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

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    Vladimir Dmitriev

    2007-06-30

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

  20. Mobile workstation for decontamination and decommissioning operations

    SciTech Connect (OSTI)

    Whittaker, W.L.; Osborn, J.F.; Thompson, B.R.

    1993-10-01

    This project is an interdisciplinary effort to develop effective mobile worksystems for decontamination and decommissioning (D&D) of facilities within the DOE Nuclear Weapons Complex. These mobile worksystems will be configured to operate within the environmental and logistical constraints of such facilities and to perform a number of work tasks. Our program is designed to produce a mobile worksystem with capabilities and features that are matched to the particular needs of D&D work by evolving the design through a series of technological developments, performance tests and evaluations. The project has three phases. In this the first phase, an existing teleoperated worksystem, the Remote Work Vehicle (developed for use in the Three Mile Island Unit 2 Reactor Building basement), was enhanced for telerobotic performance of several D&D operations. Its ability to perform these operations was then assessed through a series of tests in a mockup facility that contained generic structures and equipment similar to those that D&D work machines will encounter in DOE facilities. Building upon the knowledge gained through those tests and evaluations, a next generation mobile worksystem, the RWV II, and a more advanced controller will be designed, integrated and tested in the second phase, which is scheduled for completion in January 1995. The third phase of the project will involve testing of the RWV II in the real DOE facility.

  1. Facility Safety

    Directives, Delegations, and Requirements [Office of Management (MA)]

    2012-12-04

    The Order establishes facility and programmatic safety requirements for DOE and NNSA for nuclear safety design criteria, fire protection, criticality safety, natural phenomena hazards (NPH) mitigation, and System Engineer Program. This Page Change is limited in scope to changes necessary to invoke DOE-STD-1104, Review and Approval of Nuclear Facility Safety Basis and Safety Design Basis Document, and revised DOE-STD-3009-2014, Preparation of Nonreactor Nuclear Facility Documented Safety Analysis as required methods. DOE O 420.1C Chg 1, dated 2-27-15, supersedes DOE O 420.1C.

  2. Gas Utilization Facility Biomass Facility | Open Energy Information

    Open Energy Information (Open El) [EERE & EIA]

    Gas Utilization Facility Biomass Facility Jump to: navigation, search Name Gas Utilization Facility Biomass Facility Facility Gas Utilization Facility Sector Biomass Facility Type...

  3. Total Energy Facilities Biomass Facility | Open Energy Information

    Open Energy Information (Open El) [EERE & EIA]

    Energy Facilities Biomass Facility Jump to: navigation, search Name Total Energy Facilities Biomass Facility Facility Total Energy Facilities Sector Biomass Facility Type...

  4. Facility Safety

    Directives, Delegations, and Requirements [Office of Management (MA)]

    2002-05-20

    To establish facility safety requirements for the Department of Energy, including National Nuclear Security Administration. Cancels DOE O 420.1. Canceled by DOE O 420.1B.

  5. Facility Safety

    Directives, Delegations, and Requirements [Office of Management (MA)]

    2005-12-22

    The order establishes facility and programmatic safety requirements for nuclear and explosives safety design criteria, fire protection, criticality safety, natural phenomena hazards (NPH) mitigation, and the System Engineer Program.Chg 1 incorporates the use of DOE-STD-1189-2008, Integration of Safety into the Design Process, mandatory for Hazard Category 1, 2 and 3 nuclear facilities. Cancels DOE O 420.1A.

  6. Facility Safety

    Directives, Delegations, and Requirements [Office of Management (MA)]

    2013-06-21

    DOE-STD-1104 contains the Department's method and criteria for reviewing and approving nuclear facility's documented safety analysis (DSA). This review and approval formally document the basis for DOE, concluding that a facility can be operated safely in a manner that adequately protects workers, the public, and the environment. Therefore, it is appropriate to formally require implementation of the review methodology and criteria contained in DOE-STD-1104.

  7. Facility Safety

    Directives, Delegations, and Requirements [Office of Management (MA)]

    2000-11-20

    The objective of this Order is to establish facility safety requirements related to: nuclear safety design, criticality safety, fire protection and natural phenomena hazards mitigation. The Order has Change 1 dated 11-16-95, Change 2 dated 10-24-96, and the latest Change 3 dated 11-22-00 incorporated. The latest change satisfies a commitment made to the Defense Nuclear Facilities Safety Board (DNFSB) in response to DNFSB recommendation 97-2, Criticality Safety.

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

    SciTech Connect (OSTI)

    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.

  9. Group-III nitride based high electron mobility transistor (HEMT) with barrier/spacer layer

    DOE Patents [OSTI]

    Chavarkar, Prashant; Smorchkova, Ioulia P.; Keller, Stacia; Mishra, Umesh; Walukiewicz, Wladyslaw; Wu, Yifeng

    2005-02-01

    A Group III nitride based high electron mobility transistors (HEMT) is disclosed that provides improved high frequency performance. One embodiment of the HEMT comprises a GaN buffer layer, with an Al.sub.y Ga.sub.1-y N (y=1 or y 1) layer on the GaN buffer layer. An Al.sub.x Ga.sub.1-x N (0.ltoreq.x.ltoreq.0.5) barrier layer on to the Al.sub.y Ga.sub.1-y N layer, opposite the GaN buffer layer, Al.sub.y Ga.sub.1-y N layer having a higher Al concentration than that of the Al.sub.x Ga.sub.1-x N barrier layer. A preferred Al.sub.y Ga.sub.1-y N layer has y=1 or y.about.1 and a preferred Al.sub.x Ga.sub.1-x N barrier layer has 0.ltoreq.x.ltoreq.0.5. A 2DEG forms at the interface between the GaN buffer layer and the Al.sub.y Ga.sub.1-y N layer. Respective source, drain and gate contacts are formed on the Al.sub.x Ga.sub.1-x N barrier layer. The HEMT can also comprising a substrate adjacent to the buffer layer, opposite the Al.sub.y Ga.sub.1-y N layer and a nucleation layer between the Al.sub.x Ga.sub.1-x N buffer layer and the substrate.

  10. Working with SRNL - Our Facilities - Glovebox Facilities

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

    SRNL Our Facilities - Glovebox Facilities Govebox Facilities are sealed, protectively-lined compartments with attached gloves, allowing workers to safely handle dangerous materials...

  11. Cooperating mobile robots

    DOE Patents [OSTI]

    Harrington, John J.; Eskridge, Steven E.; Hurtado, John E.; Byrne, Raymond H.

    2004-02-03

    A miniature mobile robot provides a relatively inexpensive mobile robot. A mobile robot for searching an area provides a way for multiple mobile robots in cooperating teams. A robotic system with a team of mobile robots communicating information among each other provides a way to locate a source in cooperation. A mobile robot with a sensor, a communication system, and a processor, provides a way to execute a strategy for searching an area.

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

    SciTech Connect (OSTI)

    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. SLAC Accelerator Test Facilities

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

    FACET & TF Careers & Education Archived FACET User Facility Quick Launch About FACET & Test Facilities Expand About FACET & Test Facilities FACET & Test Facilities User Portal...

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

    SciTech Connect (OSTI)

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

    2015-05-04

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

  15. Atmospheric Radiation Measurement Radiative Atmospheric Divergence using ARM Mobile

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

    Radiative Atmospheric Divergence using ARM Mobile Facility, GERB, and AMMA Stations (RADAGAST) Beginning in January 2006, the ARM Mobile Facility (AMF) began supporting RADAGAST to provide the first well-sampled direct esti- mates of the energy balance across the atmosphere. The experiment is part of an ongoing international study of the West African monsoon system and Saharan dust storms. Stationed outside the Niger Meteo- rological Office at the Niamey International Airport, the AMF is located

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

    SciTech Connect (OSTI)

    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.

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

    DOE PAGES-Beta [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

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

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (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.

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

    DOE PAGES-Beta [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.

  1. Surfactant assisted growth of MgO films on GaN

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    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

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

    SciTech Connect (OSTI)

    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.

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

    DOE Patents [OSTI]

    Armitage, Robert D.; Weber, Eicke R.

    2005-08-16

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

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

    SciTech Connect (OSTI)

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

    2015-06-29

    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.

  6. Facility Safety

    Directives, Delegations, and Requirements [Office of Management (MA)]

    1995-10-13

    Establishes facility safety requirements related to: nuclear safety design, criticality safety, fire protection and natural phenomena hazards mitigation. Cancels DOE 5480.7A, DOE 5480.24, DOE 5480.28 and Division 13 of DOE 6430.1A. Canceled by DOE O 420.1A.

  7. Facility Safety

    Directives, Delegations, and Requirements [Office of Management (MA)]

    2012-12-04

    The Order establishes facility and programmatic safety requirements for DOE and NNSA for nuclear safety design criteria, fire protection, criticality safety, natural phenomena hazards (NPH) mitigation, and System Engineer Program. Cancels DOE O 420.1B, DOE G 420.1-2 and DOE G 420.1-3.

  8. Metro Methane Recovery Facility Biomass Facility | Open Energy...

    Open Energy Information (Open El) [EERE & EIA]

    Methane Recovery Facility Biomass Facility Jump to: navigation, search Name Metro Methane Recovery Facility Biomass Facility Facility Metro Methane Recovery Facility Sector Biomass...

  9. Vertical GaN power diodes with a bilayer edge termination

    SciTech Connect (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; 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.

  10. Vertical GaN power diodes with a bilayer edge termination

    DOE PAGES-Beta [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

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

    SciTech Connect (OSTI)

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

    2012-09-01

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

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

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    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. MobileMatch App

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

    MobileMatch VolunteerMatch Mobile App MobileMatch is a mobile extension (app) to LANL's VolunteerMatch site that allows volunteers to search, sign up and track hours. Contact Giving Campaigns & Volunteering Debbi Wersonick Community Relations & Partnerships (505) 667-7870 Email Engage anytime, anywhere with this easy and intuitive tool! Using MobileMatch app is easy mobilematch-app Now LANL volunteers can search, sign up and track hours right on their mobile device. Get on the Volunteer

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

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    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.

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

    DOE PAGES-Beta [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

  20. Research Facilities | NREL

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

    Research Facilities Our state-of-the-art facilities are available to industry entrepreneurs, engineers, scientists, and universities for researching and developing their energy technologies. Our researchers and technicians who operate these labs and facilities are ready to work with you and share their expertise. Alphabetical Listings Laboratories Test and User Facilities Popular Facilities Energy Systems Integration Facility Integrated Biorefinery Research Facility Process Development

  1. ARM - Guest Instrument Facility

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

    PlainsGuest Instrument Facility SGP Related Links Virtual Tour Facilities and Instruments Central Facility Boundary Facility Extended Facility Intermediate Facility Radiometric Calibration Facility Geographic Information ES&H Guidance Statement Operations Science Field Campaigns Visiting the Site Summer Training SGP Fact Sheet Images Information for Guest Scientists Contacts Guest Instrument Facility ARM's Guest Instrument Facility at the SGP site near Lamont, Oklahoma. ARM's Guest

  2. NREL: Research Facilities - Webmaster

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

    Your name: Your email address: Your message: Send Message Printable Version Research Facilities Home Laboratories Test & User Facilities Laboratories & Facilities by Technology...

  3. Facilities | Bioenergy | NREL

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

    Facilities At NREL's state-of-the-art bioenergy research facilities, researchers design ... facility to develop, test, evaluate, and demonstrate bioenergy processes and technologies. ...

  4. Tandem mobile robot system

    DOE Patents [OSTI]

    Buttz, James H.; Shirey, David L.; Hayward, David R.

    2003-01-01

    A robotic vehicle system for terrain navigation mobility provides a way to climb stairs, cross crevices, and navigate across difficult terrain by coupling two or more mobile robots with a coupling device and controlling the robots cooperatively in tandem.

  5. Ion mobility sensor system

    DOE Patents [OSTI]

    Xu, Jun; Watson, David B.; Whitten, William B.

    2013-01-22

    An ion mobility sensor system including an ion mobility spectrometer and a differential mobility spectrometer coupled to the ion mobility spectrometer. The ion mobility spectrometer has a first chamber having first end and a second end extending along a first direction, and a first electrode system that generates a constant electric field parallel to the first direction. The differential mobility spectrometer includes a second chamber having a third end and a fourth end configured such that a fluid may flow in a second direction from the third end to the fourth end, and a second electrode system that generates an asymmetric electric field within an interior of the second chamber. Additionally, the ion mobility spectrometer and the differential mobility spectrometer form an interface region. Also, the first end and the third end are positioned facing one another so that the constant electric field enters the third end and overlaps the fluid flowing in the second direction.

  6. Research Facility,

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

    Delivering the Data As a general condition for use of the ARM Climate Research Facility, users are required to include their data in the ARM Data Archive. All data acquired must be of sufficient quality to be useful and must be documented such that users will be able to clearly understand the meaning and organization of the data. Final, quality-assured data sets are stored in the Data Archive and are freely accessible to the general scientific community. Upon conclusion of the field campaign,

  7. Support - Facilities - Radiation Effects Facility / Cyclotron...

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

    During experiments at the Radiation Effects Facility users are assisted by the experienced ... shops are available to the users of the Radiation Effects Facility for design, ...

  8. Radiation Effects Facility - Facilities - Cyclotron Institute

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

    Radiation Effects Facility Typical DUT(device under test) set-up at the end of the Radiation Effects beamline. The Radiation Effects Facility is available for commercial, ...

  9. Harrisburg Facility Biomass Facility | Open Energy Information

    Open Energy Information (Open El) [EERE & EIA]

    2006 Database Retrieved from "http:en.openei.orgwindex.php?titleHarrisburgFacilityBiomassFacility&oldid397545" Feedback Contact needs updating Image needs updating...

  10. Brookhaven Facility Biomass Facility | Open Energy Information

    Open Energy Information (Open El) [EERE & EIA]

    2006 Database Retrieved from "http:en.openei.orgwindex.php?titleBrookhavenFacilityBiomassFacility&oldid397235" Feedback Contact needs updating Image needs updating...

  11. Energy Systems Integration Facility (ESIF): Facility Stewardship...

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

    Energy Systems Integration Facility (ESIF) Facility Stewardship Plan Revision 2.0 ... laboratory of the U.S. Department of Energy Office of Energy Efficiency & Renewable ...

  12. Mobile Technology Management

    Directives, Delegations, and Requirements [Office of Management (MA)]

    2014-05-15

    The order establishes requirements, assigns responsibilities, and provides guidance for federal mobile technology management and employee use of both government furnished and personally-owned mobile devices within DOE and NNSA. Establishes requirements for use of User Agreements to govern mobile devices used for official duties. Does not cancel other directives.

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

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    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.

  15. Kent County Waste to Energy Facility Biomass Facility | Open...

    Open Energy Information (Open El) [EERE & EIA]

    County Waste to Energy Facility Biomass Facility Jump to: navigation, search Name Kent County Waste to Energy Facility Biomass Facility Facility Kent County Waste to Energy...

  16. Stockton Regional Water Control Facility Biomass Facility | Open...

    Open Energy Information (Open El) [EERE & EIA]

    Stockton Regional Water Control Facility Biomass Facility Jump to: navigation, search Name Stockton Regional Water Control Facility Biomass Facility Facility Stockton Regional...

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

    SciTech Connect (OSTI)

    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.

  18. Ion mobility sensor

    DOE Patents [OSTI]

    Koo, Jackson C.; Yu, Conrad M.

    2005-08-23

    An ion mobility sensor which can detect both ion and molecules simultaneously. Thus, one can measure the relative arrival times between various ions and molecules. Different ions have different mobility in air, and the ion sensor enables measurement of ion mobility, from which one can identify the various ions and molecules. The ion mobility sensor which utilizes a pair of glow discharge devices may be designed for coupling with an existing gas chromatograph, where various gas molecules are already separated, but numbers of each kind of molecules are relatively small, and in such cases a conventional ion mobility sensor cannot be utilized.

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

    SciTech Connect (OSTI)

    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.

  20. Energize Mobile | Open Energy Information

    Open Energy Information (Open El) [EERE & EIA]

    Web Application Link: www.tendrilinc.comenergy-providersapplicationenergize Cost: Free Energize Mobile Screenshot References: Tendril1 Logo: Energize Mobile This...

  1. Impact of the GaN nanowire polarity on energy harvesting

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    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.

  4. Excitation mechanisms of Er optical centers in GaN epilayers

    SciTech Connect (OSTI)

    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.

  5. Surfactant assisted growth of MgO films on GaN

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    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

  9. Mobile Ice Nucleus Spectrometer

    SciTech Connect (OSTI)

    Kulkarni, Gourihar R.; Kok, G. L.

    2012-05-07

    This first year report presents results from a computational fluid dynamics (CFD) study to assess the flow and temperature profiles within the mobile ice nucleus spectrometer.

  10. Mobile Technology Management

    Directives, Delegations, and Requirements [Office of Management (MA)]

    2013-11-21

    The directive will ensure that federal organizations and employees within the Department can use mobile technology to support mission requirements in a safe and secure manner.

  11. Heavy Mobile Equipment Mechanic

    Energy.gov [DOE]

    Join the Bonneville Power Administration (BPA) for a challenging and rewarding career, while working, living, and playing in the Pacific Northwest. The Heavy Mobile Equipment Mechanic (HMEM)...

  12. Sandia National Laboratories: Facilities

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

    Facilities Bioscience Computing and Information Science Electromagnetics Facilities Electromagnetic Environments Simulator (EMES) Mode Stirred Chamber Lightning Facility Electrostatic Discharge (ESD) Laboratory Other Facilities and Capabilities Programs & Capabilities Partnership Opportunities EM News & Reports Contact Information Engineering Science Geoscience Materials Science Nanodevices and Microsystems Radiation Effects and High Energy Density Science Research Facilities

  13. CMI Unique Facility: Ferromagnetic Materials Characterization Facility |

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

    Critical Materials Institute Ferromagnetic Materials Characterization Facility The Ferromagnetic Materials Characterization Facility is one of more than a dozen unique facilities developed by the Critical Materials Institute, an Energy Innovation Hub of the U.S. Department of Energy. CMI ferromagnetic materials characterization facility at The Ames Laboratory. In the search for substitute materials to replace rare earths in permanent magnets, whenever promising materials are identified,

  14. ARM - Facility News Article

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

    April 7, 2011 Facility News Review Panel States ARM Facility "Without Peer" Bookmark and ... The latest ARM Facility review was conducted in mid-February by a six-member review panel ...

  15. McKay Bay Facility Biomass Facility | Open Energy Information

    Open Energy Information (Open El) [EERE & EIA]

    Biomass Facility Facility McKay Bay Facility Sector Biomass Facility Type Municipal Solid Waste Location Hillsborough County, Florida Coordinates 27.9903597, -82.3017728...

  16. National User Facilities

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

    National User Facilities Our Vision National User Facilities Research Areas In Focus Global Solutions ⇒ Navigate Section Our Vision National User Facilities Research Areas In Focus Global Solutions Berkeley Lab's User Facilities-Engines of Discovery Berkeley Lab's User Facilities provide state-of-the-art resources for scientists across the nation and around the world. About 10,000 researchers a year use these facilities, representing nearly one third of the total for all Department of Energy

  17. ARM - Facility News Article

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

    30, 2009 Facility News ARM Aerial Facility Leads International Discussions on Aircraft Research Bookmark and Share Five research aircraft participated in the VAMOS...

  18. ARM - Facility News Article

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

    (BERAC) published findings and recommendations from their assessment of the effectiveness of ARM Climate Research Facility as a national scientific user facility. Based on...

  19. Facilities | Photovoltaic Research | NREL

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

    the facilities below in their research and development to provide foundational support for the photovoltaic (PV) industry and PV users. Photo of the Solar Research Energy Facility. ...

  20. Facilities, Partnerships, and Resources

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

    Nuclear Energy Defense Waste Management Programs Advanced Nuclear Energy Nuclear Energy Safety Technologies Facilities Battery Abuse Testing Laboratory Cylindrical Boiling Facility ...

  1. ARM - Facility News Article

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

    13, 2014 Facility News Characterizing Ice Nuclei Over Southern Great Plains Bookmark and Share Placed on the upper platform of the SGP Guest Instrument Facility, this filter...

  2. ARM Climate Research Facility

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

    3 ARM Climate Research Facility Quarterly Ingest Status Report A Koontz C Sivaraman ... DOESC-ARM-14-003 ARM Climate Research Facility Quarterly Ingest Report First Quarter: ...

  3. ARM Climate Research Facility

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

    8 ARM Climate Research Facility Quarterly Ingest Status Report A Koontz C Sivaraman ... DOESC-ARM-14-028 ARM Climate Research Facility Quarterly Ingest Report Fourth Quarter: ...

  4. ARM Climate Research Facility

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

    3 ARM Climate Research Facility Quarterly Ingest Status Report A Koontz C Sivaraman ... DOESC-ARM-15-003 ARM Climate Research Facility Quarterly Ingest Report First Quarter: ...

  5. ARM Climate Research Facility

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

    DOESC-ARM-15-020 ARM Climate Research Facility Quarterly Ingest Report Second Quarter: ... maintained by the Atmospheric Radiation Measurement (ARM) Climate Research Facility. ...

  6. ARM Climate Research Facility

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

    ARM Climate Research Facility Quarterly Ingest Status Report A Koontz C Sivaraman April ... DOESC-ARM-14-014 ARM Climate Research Facility Quarterly Ingest Report Second Quarter: ...

  7. Facilities | Argonne National Laboratory

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

    Additionally, the 4 Tesla Magnet Facility reuses hospital MRI magnets to provide benchmarking for new muon experiments that will be performed at Fermilab. 4 Tesla Magnet Facility ...

  8. Facilities | Argonne National Laboratory

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

    Research Facility Distributed Energy Research Center Engine Research Facility Heat Transfer Laboratory Tribology Laboratory Transportation Beamline at the Advanced Photon Source...

  9. NREL: Biomass Research - Facilities

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

    Facilities At NREL's state-of-the-art biomass research facilities, researchers design and optimize processes to convert renewable biomass feedstocks into transportation fuels and...

  10. ARM - NSA Barrow Facility

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

    Barrow Facility NSA Related Links Facilities and Instruments Barrow Atqasuk Oliktok Point (AMF3) ES&H Guidance Statement Operations Science Field Campaigns Visiting the Site NSA...

  11. ARM - Facility News Article

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

    November 9, 2012 Facility News Unmanned Aircraft Test Flights Completed at Oliktok Point ... for the ARM Facility to evaluate various unmanned aerial systems (UAS) in the frigid ...

  12. ARM - Facility News Article

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

    May 15, 2008 Facility News National User Facility Organization Meets to Discuss Progress and Ideas Bookmark and Share In late April, the ARM Technical Director attended an annual...

  13. ARM - Facility News Article

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

    March 15, 2010 Facility News Closing in on Aircraft Campaign in California Bookmark and ... and Radiative Effects Study (CARES) in California, the ARM Aerial Facility is putting the ...

  14. ARM - Facility News Article

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

    February 28, 2006 Facility News Network of Infrared Thermometers Nearly Complete at SGP Bookmark and Share Red dots indicate extended facilities at SGP with the new IRTs ...

  15. ARM - Facility News Article

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

    15, 2005 Facility News Aging, Overworked Computer Network at SGP Gets Overhauled Bookmark and Share This aerial map of instruments deployed at the SGP Central Facility provides...

  16. ARM - Facility News Article

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

    to our new ARM News Center. The RSS feed will alert readers to the latest ARM science and ARM Climate Research Facility news, events, feature stories, facility updates,...

  17. ARM - Facility News Article

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

    facility use by total visitor days and facility to track actual visitors and active user research computer accounts. Historical data show an apparent relationship between the...

  18. Mobile Climate Monitoring Facility to Sample Skies in Africa...

    Energy Savers

    ... from satellite instrumentation sponsored by the European Union, will provide the first well-sampled, direct measurements of the solar and thermal radiation across the atmosphere. ...

  19. ARM - SGP Radiometric Calibration Facility

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

    Radiometric Calibration Facility SGP Related Links Virtual Tour Facilities and Instruments Central Facility Boundary Facility Extended Facility Intermediate Facility Radiometric Calibration Facility Geographic Information ES&H Guidance Statement Operations Science Field Campaigns Visiting the Site Summer Training SGP Fact Sheet Images Information for Guest Scientists Contacts SGP Radiometric Calibration Facility The Radiometric Calibration Facility (RCF) provides shortwave radiometer

  20. Guide to research facilities

    SciTech Connect (OSTI)

    Not Available

    1993-06-01

    This Guide provides information on facilities at US Department of Energy (DOE) and other government laboratories that focus on research and development of energy efficiency and renewable energy technologies. These laboratories have opened these facilities to outside users within the scientific community to encourage cooperation between the laboratories and the private sector. The Guide features two types of facilities: designated user facilities and other research facilities. Designated user facilities are one-of-a-kind DOE facilities that are staffed by personnel with unparalleled expertise and that contain sophisticated equipment. Other research facilities are facilities at DOE and other government laboratories that provide sophisticated equipment, testing areas, or processes that may not be available at private facilities. Each facility listing includes the name and phone number of someone you can call for more information.

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

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    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.

  8. Facilities | Argonne National Laboratory

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

    Facilities Argonne's Chemical Sciences and Engineering (CSE) division maintains a number of state-of-the-art facilities for advanced chemistry research. These facilities are dedicated to two main purposes: the analysis and creation of next-generation battery materials, and the analysis and generation of advanced catalysts for electrochemistry. More information on the full suite of CSE facilities can be found below. Advanced Electron Paramagnetic Resonance (EPR) Facility The Solar Energy

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

    SciTech Connect (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.; 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.

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

    SciTech Connect (OSTI)

    2012-02-13

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

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

    DOE Patents [OSTI]

    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.

  12. Calibration Facilities | Department of Energy

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

    Calibration Facilities Calibration Facilities Calibration Facilities Calibration Facilities Calibration Facilities Calibration Facilities DOE supports the development, standardization, and maintenance of calibration facilities for environmental radiation sensors. Radiation standards at the facilities are primarily used to calibrate portable surface gamma-ray survey meters and borehole logging instruments used for uranium and other mineral exploration and remedial action measurements. Standards

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

    SciTech Connect (OSTI)

    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.

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

    DOE PAGES-Beta [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

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

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (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 order of magnitude increase in band-edge to yellow luminescence intensity ratio, as measured by cathodoluminescence, indicating improved microstructural and optical properties.

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

    SciTech Connect (OSTI)

    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.

  18. CRAD, Facility Safety- Nuclear Facility Safety Basis

    Office of Energy Efficiency and Renewable Energy (EERE)

    A section of Appendix C to DOE G 226.1-2 "Federal Line Management Oversight of Department of Energy Nuclear Facilities." Consists of Criteria Review and Approach Documents (CRADs) that can be used for assessment of a contractor's Nuclear Facility Safety Basis.

  19. CRAD, Facility Safety- Nuclear Facility Design

    Office of Energy Efficiency and Renewable Energy (EERE)

    A section of Appendix C to DOE G 226.1-2 "Federal Line Management Oversight of Department of Energy Nuclear Facilities." Consists of Criteria Review and Approach Documents (CRADs) that can be used for assessment of a contractor's Nuclear Facility Design.

  20. ORPS Facility Registration Form

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

    ORPS FACILITY REGISTRATION FORM Submit completed form to: U.S. Department of Energy AU User Support EMAIL: ORPSsupport@hq.doe.gov PHONE: 800-473-4375 FAX: 301-903-9823 Note:  Only one facility per form  Type or print all entries 1. TYPE OF CHANGE  Add a Facility (Complete Section 1.A, then go to Section 2)  Change a Facility (Complete Section 1.B, then go to Section)  Delete a Facility (Complete Section 1.C, then go to Section 2) A. Add a New Facility Use this section if you are

  1. Canyon Facilities - Hanford Site

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

    About Us Projects & Facilities Canyon Facilities About Us About Hanford Cleanup Hanford History Hanford Site Wide Programs Contact Us 100 Area 118-K-1 Burial Ground 200 Area 222-S Laboratory 242-A Evaporator 300 Area 324 Building 325 Building 400 Area/Fast Flux Test Facility 618-10 and 618-11 Burial Grounds 700 Area B Plant B Reactor C Reactor Canister Storage Building and Interim Storage Area Canyon Facilities Cold Test Facility D and DR Reactors Effluent Treatment Facility Environmental

  2. Electron density and currents of AlN/GaN high electron mobility transistors with thin GaN/AlN buffer layer

    SciTech Connect (OSTI)

    Bairamis, A.; Zervos, Ch.; Georgakilas, A.; Adikimenakis, A.; Kostopoulos, A.; Kayambaki, M.; Tsagaraki, K.; Konstantinidis, G.

    2014-09-15

    AlN/GaN high electron mobility transistor (HEMT) structures with thin GaN/AlN buffer layer have been analyzed theoretically and experimentally, and the effects of the AlN barrier and GaN buffer layer thicknesses on two-dimensional electron gas (2DEG) density and transport properties have been evaluated. HEMT structures consisting of [300?nm GaN/ 200?nm AlN] buffer layer on sapphire were grown by plasma-assisted molecular beam epitaxy and exhibited a remarkable agreement with the theoretical calculations, suggesting a negligible influence of the crystalline defects that increase near the heteroepitaxial interface. The 2DEG density varied from 6.8??10{sup 12} to 2.1 10{sup 13} cm{sup ?2} as the AlN barrier thickness increased from 2.2 to 4.5?nm, while a 4.5?nm AlN barrier would result to 3.1??10{sup 13} cm{sup ?2} on a GaN buffer layer. The 3.0?nm AlN barrier structure exhibited the highest 2DEG mobility of 900?cm{sup 2}/Vs for a density of 1.3??10{sup 13} cm{sup ?2}. The results were also confirmed by the performance of 1??m gate-length transistors. The scaling of AlN barrier thickness from 1.5?nm to 4.5?nm could modify the drain-source saturation current, for zero gate-source voltage, from zero (normally off condition) to 0.63?A/mm. The maximum drain-source current was 1.1?A/mm for AlN barrier thickness of 3.0?nm and 3.7?nm, and the maximum extrinsic transconductance was 320 mS/mm for 3.0?nm AlN barrier.

  3. Technology Transitions Facilities Database

    Energy.gov [DOE]

    The types of R&D facilities at the DOE Laboratories available to the public typically fall into three broad classes depending on the mode of access: Designated User Facilities, Shared R&D...

  4. Jupiter Laser Facility

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

    Jupiter Laser Facility The commissioning of the Titan Petawatt-Class laser to LLNL's Jupiter Laser Facility (JLF) has provided a unique platform for the use of petawatt (PW)-class ...

  5. ARM Climate Research Facility

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

    9 ARM Climate Research Facility Quarterly Value-Added Product Report C Sivaraman April ... DOESC-ARM-14-009 ARM Climate Research Facility Quarterly Value-Added Product Report First ...

  6. ARM Climate Research Facility

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

    2 ARM Climate Research Facility Quarterly Value-Added Product Report C Sivaraman January ... DOESC-ARM-14-002 ARM Climate Research Facility Quarterly Value-Added Product Report First ...

  7. ARM Climate Research Facility

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

    3 ARM Climate Research Facility Quarterly Value-Added Product Report Chitra Sivaraman ... DOESC-ARM-11-023 ARM Climate Research Facility Quarterly Value-Added Product Report ...

  8. ARM Climate Research Facility

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

    3 ARM Climate Research Facility Quarterly Ingest Status Report A Koontz C Sivaraman July ... DOESC-ARM-14-023 ARM Climate Research Facility Quarterly Ingest Report Third Quarter: ...

  9. ARM Climate Research Facility

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

    0 ARM Climate Research Facility Quarterly Value-Added Product Report C Sivaraman July 2014 ... DOESC-ARM-14-020 ARM Climate Research Facility Quarterly Value-Added Product Report Third ...

  10. ARM Climate Research Facility

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

    2 ARM Climate Research Facility Quarterly Value-Added Product Report C Sivaraman February ... DOESC-ARM-12-002 ARM Climate Research Facility Quarterly Value-Added Product Report First ...

  11. ARM Climate Research Facility

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

    1 ARM Climate Research Facility Quarterly Value-Added Product Report Chitra Sivaraman ... DOESC-ARM-11-021 ARM Climate Research Facility Quarterly Value-Added Product Report Third ...

  12. ARM - Facility News Article

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

    facility use by total visitor days-broken down by institution type, gender, race, citizenship, visitor role, visit purpose, and facility-for actual visitors and for active user...

  13. ARM - Facility News Article

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

    Farewell to Dan Nelson, SGP Facilities Manager Bookmark and Share Dan Nelson Dan Nelson Dan Nelson, long-time facilities manager at the ARM Southern Great Plains site, is heading...

  14. Facilities | Jefferson Lab

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

    JLab Buildings Facilities Management & Logistics is responsible for performing or specifying performance of all Jefferson Lab facility maintenance. A D D I T I O N A L L I N K S:...

  15. WIPP Nuclear Facilities Transparency

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

    Nuclear Facilities Transparency Resources Transparency Home Purpose of Transparency Stakeholders Transparency Implementation Transparency Risks Transparency Technologies Other ...

  16. ARM - Facility News Article

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

    in atmospheric and terrestrial ecosystem research participated in the workshop, ... Chemical and Biological Measurements Ecosystem Aerial Facility Measurements BER staff ...

  17. Argonne Leadership Computing Facility

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

    ARGONNE LEADERSHIP COMPUTING FACILITY The 10-petaflops Mira supercomputer The Argonne Leadership Computing Facility (ALCF), a U.S. Department of Energy (DOE) Office of Science User Facility, provides its user community with computing time and staff support to pursue significant breakthroughs in science and engineering. The ALCF is one of two DOE leadership computing facilities in the nation dedicated to open science. www.alcf.anl.gov ENABLING SCIENCE With hundreds of thousands of processors

  18. Expertise & Facilities

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

    Expertise & Facilities Expertise & Facilities Our full spectrum of end-to-end integrated capabilities in explosives make Los Alamos the ideal place to develop, characterize, and test all types of explosives and explosives threat scenarios. v Award-winning scientists, state-of-the-art facilities LACED is built upon Los Alamos' unparalleled explosives detection capabilities derived from the expertise of award-winning scientists and state-of-the-art facilities. LACED is made up of 57

  19. NEAC Facilities Subcommittee Report

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

    Facilities Subcommittee Report Presentation to the NEAC Committee 12/11/2015 John I. Sackett Facilities Subcommittee Members * John Ahearne * Dana Christensen * Tom Cochran * Mike Corradini * Dave Hill * Hussein Khalil * Andy Klein * Paul Murray * John Sackett, chair Subcommittee Objectives * The objective of our deliberations has been to help DOE-NE develop a means to identify, prioritize and make available those facilities important to Nuclear Energy Research and Development. - All facilities

  20. WIPP - Public Reading Facilities

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

    Public Reading Facilities/Electronic Reading Facilities The Freedom of Information Act (FOIA) and Electronic FOIA (E-FOIA) require that various specific types of records, as well as various other records, be maintained in public reading facilities. Before you submit a FOIA request, we recommend you contact or visit the appropriate public reading facility to determine if the records you are seeking have already been released. The U.S. Department of Energy (DOE), as well as other related DOE

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

    SciTech Connect (OSTI)

    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.

  2. Correlation ion mobility spectroscopy

    DOE Patents [OSTI]

    Pfeifer, Kent B.; Rohde, Steven B.

    2008-08-26

    Correlation ion mobility spectrometry (CIMS) uses gating modulation and correlation signal processing to improve IMS instrument performance. Closely spaced ion peaks can be resolved by adding discriminating codes to the gate and matched filtering for the received ion current signal, thereby improving sensitivity and resolution of an ion mobility spectrometer. CIMS can be used to improve the signal-to-noise ratio even for transient chemical samples. CIMS is especially advantageous for small geometry IMS drift tubes that can otherwise have poor resolution due to their small size.

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

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    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.

  5. Listing of Defense Nuclear Facilities

    Energy Savers

    Listing of Defense Nuclear Facilities The facilities listed below are considered DOE defense nuclear facilities for purposes of Section 3161. Kansas City Plant Pinellas Plant Mound ...

  6. Wheelabrator Westchester Biomass Facility | Open Energy Information

    Open Energy Information (Open El) [EERE & EIA]

    Westchester Biomass Facility Jump to: navigation, search Name Wheelabrator Westchester Biomass Facility Facility Wheelabrator Westchester Sector Biomass Facility Type Municipal...

  7. Hydrodynamic Testing Facilities Database | Open Energy Information

    Open Energy Information (Open El) [EERE & EIA]

    Hydrodynamic Testing Facilities Database (Redirected from Hydrodynamic Testing Facilities) Jump to: navigation, search Facility Operators By viewing Hydrodynamic Testing Facilities...

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

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    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.

  10. Yellow luminescence and related deep states in undoped GaN

    SciTech Connect (OSTI)

    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}

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

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    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.

  13. Benefits of Using Mobile Transformers and Mobile Substations for Rapidly

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

    Restoring Electrical Service: a Report to the United States Congress Pursuant to Section 1816 of the Energy Policy Act of 2005 (August 2006) | Department of Energy Using Mobile Transformers and Mobile Substations for Rapidly Restoring Electrical Service: a Report to the United States Congress Pursuant to Section 1816 of the Energy Policy Act of 2005 (August 2006) Benefits of Using Mobile Transformers and Mobile Substations for Rapidly Restoring Electrical Service: a Report to the United

  14. Mobile lighting apparatus

    DOE Patents [OSTI]

    Roe, George Michael; Klebanoff, Leonard Elliott; Rea, Gerald W; Drake, Robert A; Johnson, Terry A; Wingert, Steven John; Damberger, Thomas A; Skradski, Thomas J; Radley, Christopher James; Oros, James M; Schuttinger, Paul G; Grupp, David J; Prey, Stephen Carl

    2013-05-14

    A mobile lighting apparatus includes a portable frame such as a moveable trailer or skid having a light tower thereon. The light tower is moveable from a stowed position to a deployed position. A hydrogen-powered fuel cell is located on the portable frame to provide electrical power to an array of the energy efficient lights located on the light tower.

  15. Mobil lube dewaxing technologies

    SciTech Connect (OSTI)

    Baker, C.L.; McGuiness, M.P.

    1995-09-01

    Currently, the lube refining industry is in a period of transition, with both hydroprocessing and catalytic dewaxing gathering momentum as replacements for solvent extraction and solvent dewaxing. In addition, lube product quality requirements have been increasing, both in the US and abroad. Mobil has developed a broad array of dewaxing catalytic technologies which can serve refiners throughout the stages of this transition. In the future, lube feedstocks which vary in source and wax content will become increasingly important, requiring an optimized system for highest performance. The Mobil Lube Dewaxing (MLDW) process is the work-horse of the catalytic dewaxing technologies, being a robust, low cost technology suitable for both solvent extracted and hydrocracked feeds. The Mobil Selective Dewaxing (MSDW) process has been recently introduced in response to the growth of hydroprocessing. MSDW requires either severely hydrotreated or hydrocracked feeds and provides improved lube yields and VI. For refiners with hydrocrackers and solvent dewaxing units, Mobil Wax Isomerization (MWI) technology can make higher VI base stocks to meet the growing demand for very high quality lube products. A review of these three technologies is presented in this paper.

  16. The DOE ARM Aerial Facility

    SciTech Connect (OSTI)

    Schmid, Beat; Tomlinson, Jason M.; Hubbe, John M.; Comstock, Jennifer M.; Mei, Fan; Chand, Duli; Pekour, Mikhail S.; Kluzek, Celine D.; Andrews, Elisabeth; Biraud, S.; McFarquhar, Greg

    2014-05-01

    The Department of Energy Atmospheric Radiation Measurement (ARM) Program is a climate research user facility operating stationary ground sites that provide long-term measurements of climate relevant properties, mobile ground- and ship-based facilities to conduct shorter field campaigns (6-12 months), and the ARM Aerial Facility (AAF). The airborne observations acquired by the AAF enhance the surface-based ARM measurements by providing high-resolution in-situ measurements for process understanding, retrieval-algorithm development, and model evaluation that are not possible using ground- or satellite-based techniques. Several ARM aerial efforts were consolidated into the AAF in 2006. With the exception of a small aircraft used for routine measurements of aerosols and carbon cycle gases, AAF at the time had no dedicated aircraft and only a small number of instruments at its disposal. In this "virtual hangar" mode, AAF successfully carried out several missions contracting with organizations and investigators who provided their research aircraft and instrumentation. In 2009, AAF started managing operations of the Battelle-owned Gulfstream I (G-1) large twin-turboprop research aircraft. Furthermore, the American Recovery and Reinvestment Act of 2009 provided funding for the procurement of over twenty new instruments to be used aboard the G-1 and other AAF virtual-hangar aircraft. AAF now executes missions in the virtual- and real-hangar mode producing freely available datasets for studying aerosol, cloud, and radiative processes in the atmosphere. AAF is also engaged in the maturation and testing of newly developed airborne sensors to help foster the next generation of airborne instruments.

  17. Working with SRNL - Our Facilities- Rapid Fabrication Facility

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

    Rapid Fabrication Facility Working with SRNL Our Facilities - Rapid Fabrication Facility At SRNL's Rapid Fabrication Facility, low-cost prototypes are produced, as well as parts and complete working models

  18. Mobility Agreement for Criminal Investigators | Department of...

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

    Mobility Agreement for Criminal Investigators Mobility Agreement for Criminal Investigators PDF icon Mobility Agreement More Documents & Publications Semiannual Report to Congress: ...

  19. Mobility platform coupling device and method for coupling mobility platforms

    DOE Patents [OSTI]

    Shirey, David L.; Hayward, David R.; Buttz, James H.

    2002-01-01

    A coupling device for connecting a first mobility platform to a second mobility platform in tandem. An example mobility platform is a robot. The coupling device has a loose link mode for normal steering conditions and a locking position, tight link mode for navigation across difficult terrain and across obstacles, for traversing chasms, and for navigating with a reduced footprint in tight steering conditions.

  20. Department of Energy Facilities | Department of Energy

    Energy Savers

    Department of Energy Facilities Department of Energy Facilities Department of Energy Facilities View All Maps Addthis...

  1. Department of Energy Facilities | Department of Energy

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

    Department of Energy Facilities Department of Energy Facilities Department of Energy Facilities

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

    SciTech Connect (OSTI)

    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%.

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

    SciTech Connect (OSTI)

    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.

  4. Mobile Robotics Activities in DOE Laboratories

    SciTech Connect (OSTI)

    Ron Lujan; Jerry Harbour; John T. Feddema; Sharon Bailey; Jacob Barhen; David Reister

    2005-03-01

    This paper will briefly outline major activities in Department of Energy (DOE) Laboratories focused on mobile platforms, both Unmanned Ground Vehicles (UGV’s) as well as Unmanned Air Vehicles (UAV’s). The activities will be discussed in the context of the science and technology construct used by the DOE Technology Roadmap for Robotics and Intelligent Machines (RIM)1 published in 1998; namely, Perception, Reasoning, Action, and Integration. The activities to be discussed span from research and development to deployment in field operations. The activities support customers in other agencies. The discussion of "perception" will include hyperspectral sensors, complex patterns discrimination, multisensor fusion and advances in LADAR technologies, including real-world perception. "Reasoning" activities to be covered include cooperative controls, distributed systems, ad-hoc networks, platform-centric intelligence, and adaptable communications. The paper will discuss "action" activities such as advanced mobility and various air and ground platforms. In the RIM construct, "integration" includes the Human-Machine Integration. Accordingly the paper will discuss adjustable autonomy and the collaboration of operator(s) with distributed UGV’s and UAV’s. Integration also refers to the applications of these technologies into systems to perform operations such as perimeter surveillance, large-area monitoring and reconnaissance. Unique facilities and test beds for advanced mobile systems will be described. Given that this paper is an overview, rather than delve into specific detail in these activities, other more exhaustive references and sources will be cited extensively.

  5. Integrated Disposal Facility - Hanford Site

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

    Area 324 Building 325 Building 400 AreaFast Flux Test Facility 618-10 and 618-11 ... Facilities Cold Test Facility D and DR Reactors Effluent Treatment Facility ...

  6. Long range hopping mobility platform.

    SciTech Connect (OSTI)

    Spletzer, Barry Louis; Fischer, Gary John

    2003-03-01

    Sandia National Laboratories has developed a mesoscale hopping mobility platform (Hopper) to overcome the longstanding problems of mobility and power in small scale unmanned vehicles. The system provides mobility in situations such as negotiating tall obstacles and rough terrain that are prohibitive for other small ground base vehicles. The Defense Advanced Research Projects Administration (DARPA) provided the funding for the hopper project.

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

    SciTech Connect (OSTI)

    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.

  8. Kammerer Solar Power Facility | Open Energy Information

    Open Energy Information (Open El) [EERE & EIA]

    Power Facility Facility Kammerer Solar Power Facility Sector Solar Facility Type Photovoltaics Facility Status In Service Developer Recurrent Energy Energy Purchaser Sacramento...

  9. Spearville Wind Energy Facility | Open Energy Information

    Open Energy Information (Open El) [EERE & EIA]

    Wind Energy Facility Jump to: navigation, search Name Spearville Wind Energy Facility Facility Spearville Wind Energy Facility Sector Wind energy Facility Type Commercial Scale...

  10. Baseline Wind Energy Facility | Open Energy Information

    Open Energy Information (Open El) [EERE & EIA]

    Wind Energy Facility Jump to: navigation, search Name Baseline Wind Energy Facility Facility Baseline Wind Energy Facility Sector Wind energy Facility Type Commercial Scale Wind...

  11. Ainsworth Wind Energy Facility | Open Energy Information

    Open Energy Information (Open El) [EERE & EIA]

    Ainsworth Wind Energy Facility Jump to: navigation, search Name Ainsworth Wind Energy Facility Facility Ainsworth Wind Energy Facility Sector Wind energy Facility Type Commercial...

  12. Searsburg Wind Energy Facility | Open Energy Information

    Open Energy Information (Open El) [EERE & EIA]

    Searsburg Wind Energy Facility Jump to: navigation, search Name Searsburg Wind Energy Facility Facility Searsburg Wind Energy Facility Sector Wind energy Facility Type Commercial...

  13. Argonne Wakefield Accelerator Facility | Argonne National Laboratory

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

    Facilities 4 Tesla Magnet Facility Argonne Wakefield Accelerator Facility Argonne Wakefield Accelerator Facility Argonne Wakefield Accelerator Facility In order to achieve the high ...

  14. Mobile Biomass Pelletizing System

    SciTech Connect (OSTI)

    Thomas Mason

    2009-04-16

    This grant project examines multiple aspects of the pelletizing process to determine the feasibility of pelletizing biomass using a mobile form factor system. These aspects are: the automatic adjustment of the die height in a rotary-style pellet mill, the construction of the die head to allow the use of ceramic materials for extreme wear, integrating a heat exchanger network into the entire process from drying to cooling, the use of superheated steam for adjusting the moisture content to optimum, the economics of using diesel power to operate the system; a break-even analysis of estimated fixed operating costs vs. tons per hour capacity. Initial development work has created a viable mechanical model. The overall analysis of this model suggests that pelletizing can be economically done using a mobile platform.

  15. ARM - Facility News Article

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

    A-OK in Oklahoma: SGP Reconfiguration is Right on Track Bookmark and Share ARM staff meet milestones in completing instrument upgrades A new extended facility site (39) was installed, including 3-channel microwave radiometer. A new extended facility site (39) was installed, including 3-channel microwave radiometer. As part of the next-generation ARM Facility initiative set forth in the 2014 Decadal Vision, the Southern Great Plains (SGP) site in Oklahoma has been undergoing a reconfiguration to

  16. ARM - Facility News Article

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

    July 10, 2007 [Facility News] Jim Mather Selected as New ARM Technical Director Bookmark and Share Congratulations to Dr. Jim Mather, who will take the position of Technical Director of the ARM Climate Research Facility effective August 1, 2007. The Technical Director is responsible and accountable for the successful overall management of the user facility and works with the other ARM managers to this end. Jim's leadership will be critical for the successful development and evolution of the

  17. ARM - Facility News Article

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

    9, 2014 [Facility News] Workshops Begin for ARM Megasites Bookmark and Share While the mission of the ARM Climate Research Facility has not changed, it is undergoing a reconfiguration to better support the linking of ARM measurements with process-oriented models. The facility reconfiguration, presented at the recent Atmospheric System Research meeting, will involve three main components: Augmenting measurements at the ARM Southern Great Plains site and the two sites on the North Slope of Alaska,

  18. Manufacturing Demonstration Facility

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

    Manufacturing Demonstration Facility Bill Peter Director, Manufacturing Demonstration Facility Oak Ridge National Laboratory Advanced Manufacturing Office Peer Review June 14-15, 2016 This presentation does not contain any proprietary, confidential, or otherwise restricted information. Today, ORNL is a leading science and energy laboratory The Manufacturing Demonstration Facility at Oak Ridge National Laboratory * R&D in materials, systems, and computational applications to develop broad of

  19. ARM - Facility News Article

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

    October 17, 2016 [Facility News] Data Developers Meeting Helps Align ARM Staff with Facility Goals Bookmark and Share Sessions indicate the ARM reconfiguration is on track, but there is more work ahead Giving an overview of accomplishments, user feedback, and goals is ARM Technical Director Jim Mather. Giving an overview of accomplishments, user feedback, and goals is ARM Technical Director Jim Mather. During the last week of September, about 55 ARM Climate Research Facility staff members

  20. NREL: Transportation Research - Facilities

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

    Facilities NREL conducts vehicles and fuels research in laboratories and test sites on its 327-acre main campus in Golden, Colorado, and at specialized facilities within the region. Industry, government, and university partners benefit from access to NREL equipment and facilities tailored to analyze a broad spectrum of energy-efficient vehicle and fuel technologies and innovations. NREL engineers and researchers work closely with a wide variety of partners to research and develop advanced

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

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    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.

  3. NETL CT Imaging Facility

    SciTech Connect (OSTI)

    2013-09-04

    NETL's CT Scanner laboratory is equipped with three CT scanners and a mobile core logging unit that work together to provide characteristic geologic and geophysical information at different scales, non-destructively.

  4. NETL CT Imaging Facility

    ScienceCinema (OSTI)

    None

    2014-05-21

    NETL's CT Scanner laboratory is equipped with three CT scanners and a mobile core logging unit that work together to provide characteristic geologic and geophysical information at different scales, non-destructively.

  5. Monsanto MOUND FACILITY

    Office of Legacy Management (LM)

    Monsanto . MOUND FACILITY Operated for the United States Department of Energy March 26, 1981 Dr. William E. Mott, Director Environmental and Safety Engineering Division U. S. ...

  6. ARM - Facility News Article

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

    New Backup Software Improves Processing, Reliability at Data Management Facility Bookmark ... In May, significant progress was made on upgrades to the data backup software in the DMF. ...

  7. ARM - Facility News Article

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

    , 2011 Facility News Snazzy New Spectroradiometers Sport Same Body, Different Mind Bookmark and Share Connor Flynn, a scientist at Pacific Northwest National Laboratory and the...

  8. ARM - Facility News Article

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

    ARM Aerial Facility's Lofty Goal: Collect Crucial Arctic Climate Change Data with Unmanned Aerial Systems Bookmark and Share ARM bolsters aerial data collection capabilities with ...

  9. ARM - Facility News Article

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

    9, 2009 Facility News Climate Change Prediction Program Funding Opportunity Announced Bookmark and Share The U.S. Department of Energy's Office of Science is now accepting ...

  10. ARM - Facility News Article

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

    5, 2008 Facility News Talk About Climate Change: Radiometer Moves from Arctic to South America Bookmark and Share Dockside in Charleston, South Carolina, the newly installed GVRP ...

  11. Existing Facilities Rebate Program

    Energy.gov [DOE]

    The NYSERDA Existing Facilities program merges the former Peak Load Reduction and Enhanced Commercial and Industrial Performance programs. The new program offers a broad array of different...

  12. ARM - Facility News Article

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

    25, 2011 Education, Facility News Remote Schools Welcome Much-Needed Resources Bookmark and Share Students at the Children's Academy Centre in Lorengau gather as Jacklyn Soko,...

  13. ARM - Facility News Article

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

    Due to their remote locations, many of these field facilities still rely on dialup Internet connections and are susceptible to frequent power outages. After uncovering a minor but ...

  14. ARM - Facility News Article

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

    Instrument States Database Up and Running Bookmark and Share At the three ARM Climate Research Facility locales (Southern Great Plains, Tropical Western Pacific, and North Slope of...

  15. Wind Manufacturing Facilities

    Energy.gov [DOE]

    America's wind energy industry supports a growing domestic industrial base. Check out this map to find manufacturing facilities in your state. Last updated December 2013.

  16. ARM - Facility News Article

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

    October 15, 2004 Facility News Data Quality Application Gives Data Browsers a New View Bookmark and Share Plot Browser, now available through the Data Quality Health and Status...

  17. Carbon Fiber Technology Facility

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

    occupancy * Equipment installation complete * Start-up testing and commissioning * 35 million DOE investment under ARRA * 42,000 sf facility with 390-ft. long processing line. ...

  18. ARM - Facility News Article

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

    subcomponents. The ARM Climate Research Facility maintains research sites around the globe, each with a suite of instruments that must be maintained and calibrated to ensure the...

  19. ARM - Facility News Article

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

    and Share As a national user facility, ARM is accessible to scientists around the globe for interdisciplinary research related to earth systems. In a continuing effort to...

  20. ARM - Facility News Article

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

    October 31, 2008 Facility News Breakthrough User Interface Delivers Statistical Views of Data Bookmark and Share With its "drill-down" preview feature, the Statistical Browser is...

  1. ARM - Facility News Article

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

    2, 2015 Facility News, Publications LASSO Implementation Strategy Report Available Bookmark and Share "Data cubes" that combine observations, model output, and metrics will be...

  2. ARM - Facility News Article

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

    Records Set Again; New Process Enhances Reporting of User Facility Statistics Bookmark and Share The 2006 year-end ARM statistics included a spatial distribution of global (shown...

  3. ARM - Facility News Article

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

    June 27, 2007 Data Announcements, Facility News Data from the NOAA Climate Reference Network for Barrow, AK, and Stillwater, OK, are Available Through the External Data Center...

  4. ARM - Facility News Article

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

    17, 2013 Facility News Data Sharing for Climate Research with India Now Official Bookmark and Share Aerosol instruments operate at the IISc Challakere campus, located about 150...

  5. Programs & User Facilities

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

    Fusion Energy Sciences Magnetic Fusion Experiments Plasma Surface Interactions - SciDAC ... Detector Collaboration at RHIC Ultra-Cold Neutron Facility Workforce Development for ...

  6. NERSC Central Login Facility

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

    Login Facility Please login below with your NIM username and password to access pages with personalized information and NERSC user-only content. Username: Password: Login Need to...

  7. ARM - Facility News Article

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

    Dr. Jian Wang, Brookhaven National Laboratory The ARM Science Board serves as an independent review body for the ARM Facility to maintain excellence and integrity in the review ...

  8. ARM - Facility News Article

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

    September 30, 2008 Facility News Education and Outreach Activities in the Tropics Get a Tune-up Bookmark and Share Leonard Jonli (right), Assistant Administrator for Education on...

  9. ARM - Facility News Article

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

    User Facilities in Spotlight at Inaugural Office of Science Graduate Fellows Conference Bookmark and Share Office of Science director Dr. William Brinkman delivers his ...

  10. ARM - Facility News Article

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

    Facility (AMF) is being packed up and shipped from Richland, Washington, to the Point Reyes National Seashore north of San Francisco, California. There, it will be reassembled in...

  11. ARM - Facility News Article

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

    Facility (AMF), an identical CCN instrument was deployed in 2005 during the AMF field campaign at Point Reyes, California, and is currently operating at Niamey, Niger, West Africa...

  12. ARM - Facility News Article

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

    October 16, 2007 Facility News ARM Education and Outreach Program Awarded Funding by National Science Foundation Bookmark and Share Andrea Maestas, ARM Education and Outreach...

  13. Light-Source Facilities

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

    ... Facilities, Denmark ISI-800 - Institute of Metal Physics, Ukraine Kharkov Institute of Physics and Technology, Ukraine KSRS - Kurchatov Synchrotron Radiation Source, Russian ...

  14. ARM - Facility News Article

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

    October 13, 2014 Education, Facility News ARM Educational Outreach Celebrates Earth Science Week 2014 Bookmark and Share This week, Professor Polar Bear and the Climate Kids are...

  15. ARM - Facility News Article

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

    0, 2014 Education, Facility News ARM's Educational Outreach Recognized Bookmark and Share Resources selected by the Climate Literacy and Energy Awareness Network (CLEAN) must...

  16. ARM - Facility News Article

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

    14, 2012 Education, Facility News ARM Education Receives Seal of Approval Bookmark and Share Resources selected by the Climate Literacy and Energy Awareness Network (CLEAN) must...

  17. ARM - Facility News Article

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

    Early Career Research Program Bookmark and Share Pierre Gentine, Columbia University in New York Pierre Gentine, Columbia University in New York Two ARM Facility users and...

  18. ARM - Facility News Article

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

    in a first person view, using curiosity as their guide. Vivid Learning Systems' Nick Bauer takes stills on top of the Radiometric Calibration Facility. Vivid Learning Systems'...

  19. ARM - Facility News Article

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

    Research Facility's North Slope of Alaska (NSA) locale was completed the weekend of April ... observations during arctic winters at the NSA and other high latitude research sites. ...

  20. ARM - Facility News Article

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

    ARM Climate Research Facility Lends Support to Military Flare Tests Bookmark and Share Prior to the flare tests, SGP personnel informed local landowners and fire departments about ...

  1. ARM - Facility News Article

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

    Military Facilities, Restricted Airspace Okayed to Support Arctic Cloud Experiment Bookmark and Share As shown in this aerial photo of Oliktok Point, Alaska, the USAF Long Range ...

  2. Cell Prototyping Facility

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

    Cell Prototyping Facility - Sandia Energy Energy Search Icon Sandia Home Locations Contact ... Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power ...

  3. ARM - Facility News Article

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

    15 and 21 will remain intact, along with the Central Facility (C1) near Lamont. Instrumentation at the remaining sites will be consolidated into the new, smaller footprint....

  4. ARM - Facility News Article

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

    September 30, 2004 Facility News New Instrumentation on Proteus Aircraft Tested Bookmark and Share This fall, the ARM-Unmanned Aerospace Vehicle Program-specifically, the Proteus ...

  5. ARM - Facility News Article

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

    21, 2014 Facility News DOE Early Career Research Awardee to Study Water Cycle Bookmark and Share Mike Pritchard Mike Pritchard Recently announced by the DOE Office of Science...

  6. ARM - Facility News Article

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

    January 21, 2008 Facility News ARM Kicks Off 88th American Meteorological Society Annual Meeting at WeatherFest Bookmark and Share Jim Mather, ARM Technical Director,...

  7. ARM - Facility News Article

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

    December 31, 2008 Facility News Arctic Field Campaign Data and Instrument Performance Reviewed at Workshop Bookmark and Share Both wings of the Canadian National Research...

  8. ARM - Facility News Article

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

    More Server Power Improves Performance at the ARM Data Management Facility Bookmark and Share Recently, several new Sun servers joined the production system at the ARM Data ...

  9. ARM - Facility News Article

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

    For continuity, the website still features the familiar faces of Professor Polar Bear, Teacher Turtle, and PI Prairie Dog (each representing an ARM Climate Research Facility site), ...

  10. ARM - Facility News Article

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

    This report reflects the ARM Facility's contributions to climate model improvements and leadership in providing advanced scientific capabilities for understanding atmospheric...

  11. ARM - Facility News Article

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

    October 16, 2007 Facility News The Southern Great Plains Site Welcomes Keith Richardson Bookmark and Share Keith Richardson was hired as a Computer Network Manager at the SGP...

  12. ARM - Facility News Article

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

    October 6, 2010 Facility News Call for Abstracts for Aquatic Sciences Meeting in 2011 Bookmark and Share The next biennial American Society for Limnology and Oceanography (ASLO)...

  13. ARM - Facility News Article

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

    15, 2007 Facility News Commercial Infrared Sky Imagers Compared Bookmark and Share Three of the four instruments used in the sky imager intercomparison are visible in this photo...

  14. ARM - Facility News Article

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

    ARM Climate Research Facility Communication Products Garner Awards in Competition Bookmark ... Chapter of the Society for Technical Communication, qualifying it for the international ...

  15. ARM - Facility News Article

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

    Numerous other instruments are situated nearby. In September 2004, the ARM Climate Research Facility Operations staff installed a new 2-channel Narrow Field of View (NFOV)...

  16. ARM - Facility News Article

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

    ER-AERI Bookmark and Share Thanks to quick actions on the part of numerous ARM Climate Research Facility operations staff, an Extended Range Atmospheric Emitted Radiance...

  17. ARM - Facility News Article

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

    News New Ceilometer Evaluated at Southern Great Plains Site Bookmark and Share Dan Nelson, SGP facilities manager, inspects the new ceilometer during its evaluation period on...

  18. ARM - Facility News Article

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

    Realizing the increasing importance of new methods of science communication, the ARM Facility began efforts last year to expand its multimedia outreach. To begin this process, ...

  19. NSA Atqasuk Facility

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

    Inactive NSA Related Links Virtual Tour Facilities and Instruments Barrow Atqasuk Oliktok Point (AMF3) ES&H Guidance Statement Operations Science Field Campaigns Visiting the Site NSA Fact Sheet Images Information for Guest Scientists Contacts NSA Atqasuk Facility-Inactive Location: 70° 28' 19.11" N, 157° 24' 28.99" W Altitude: 20 meters The Atqasuk facility, which was part of the larger ARM Climate Research Facility (ARM) North Slope of Alaska site, was installed the summer of

  20. NSA Barrow Facility

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

    Barrow Facility NSA Related Links Virtual Tour Facilities and Instruments Barrow Atqasuk Oliktok Point (AMF3) ES&H Guidance Statement Operations Science Field Campaigns Visiting the Site NSA Fact Sheet Images Information for Guest Scientists Contacts NSA Barrow Facility Location: 71° 19' 23.73" N, 156° 36' 56.70" W Altitude: 8 meters The Barrow facility was dedicated in July 1997 and chosen because the Arctic is particularly sensitive to climate changes. Barrow is located at the

  1. ARM - Facility News Article

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

    March 15, 2005 Facility News Japanese Collaborators Take A Long Look at Lightning Bookmark and Share Mounted on tripods, numerous interferometer antennas are secured to the roof...

  2. ARM - Facility News Article

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

    Facility Darwin site. Photo courtesy of NASA Goddard Space Flight Center. Science collaborators at the Australian Bureau of Meteorology (BOM) and the Australian Commonwealth...

  3. Facility Survey & Transfer

    Energy.gov [DOE]

    As DOE facilities become excess, many that are radioactively and/or chemically contaminated will become candidate for transfer to DOE-EM for deactivation and decommissioning.

  4. ARM - Facility News Article

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

    Show Relationship Between Sea Ice and Precipitation Over Land Bookmark and Share Walter Brower, Barrow site facilities manager for ARM, cleans the sampling surface in...

  5. Facilities | Department of Energy

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

    and virtual tools and enable demonstration in targeted technical areas of manufacturing. ... Oak Ridge Manufacturing Demonstration Facility (MDF) Work at the Oak Ridge MDF focuses on ...

  6. Lighting Test Facilities

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

    Lighting-Test-Facilities Sign In About | Careers | Contact | Investors | bpa.gov Search Policy & Reporting Expand Policy & Reporting EE Sectors Expand EE Sectors Technology &...

  7. ARM - Facility News Article

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

    30, 2007 Facility News High-Speed Internet Deflects Information Overload Bookmark and Share Covering approximately 143,000 square kilometers in Oklahoma and Kansas, instruments...

  8. ARM - Facility News Article

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

    20, 2008 Facility News ARM Scientists Lead International Radiation Symposium in Brazil Bookmark and Share The ARM Science Team showed up in force at the 2008 International...

  9. Environmental Technology Verification of Mobile Sources Control...

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

    Environmental Technology Verification of Mobile Sources Control Technologies Environmental Technology Verification of Mobile Sources Control Technologies 2005 Diesel Engine...

  10. Progress Update: Creating Mobile Emission Reduction Credits ...

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

    Update: Creating Mobile Emission Reduction Credits Progress Update: Creating Mobile Emission Reduction Credits 2004 Diesel Engine Emissions Reduction (DEER) Conference ...

  11. Securing mobile code.

    SciTech Connect (OSTI)

    Link, Hamilton E.; Schroeppel, Richard Crabtree; Neumann, William Douglas; Campbell, Philip LaRoche; Beaver, Cheryl Lynn; Pierson, Lyndon George; Anderson, William Erik

    2004-10-01

    If software is designed so that the software can issue functions that will move that software from one computing platform to another, then the software is said to be 'mobile'. There are two general areas of security problems associated with mobile code. The 'secure host' problem involves protecting the host from malicious mobile code. The 'secure mobile code' problem, on the other hand, involves protecting the code from malicious hosts. This report focuses on the latter problem. We have found three distinct camps of opinions regarding how to secure mobile code. There are those who believe special distributed hardware is necessary, those who believe special distributed software is necessary, and those who believe neither is necessary. We examine all three camps, with a focus on the third. In the distributed software camp we examine some commonly proposed techniques including Java, D'Agents and Flask. For the specialized hardware camp, we propose a cryptographic technique for 'tamper-proofing' code over a large portion of the software/hardware life cycle by careful modification of current architectures. This method culminates by decrypting/authenticating each instruction within a physically protected CPU, thereby protecting against subversion by malicious code. Our main focus is on the camp that believes that neither specialized software nor hardware is necessary. We concentrate on methods of code obfuscation to render an entire program or a data segment on which a program depends incomprehensible. The hope is to prevent or at least slow down reverse engineering efforts and to prevent goal-oriented attacks on the software and execution. The field of obfuscation is still in a state of development with the central problem being the lack of a basis for evaluating the protection schemes. We give a brief introduction to some of the main ideas in the field, followed by an in depth analysis of a technique called 'white-boxing'. We put forth some new attacks and improvements

  12. Mobile worksystems for decontamination and dismantlement

    SciTech Connect (OSTI)

    Osborn, J.; Bares, L.C.; Thompson, B.R.

    1995-10-01

    Many DOE nuclear facilities have aged beyond their useful lifetimes. They need to be decommissioned in order to be safe for human presence in the short term, to eventually recover valuable materials they contain, and ultimately to be transitioned to alternative uses or green field conditions. Decontamination and dismantlement are broad classes of activities that will enable these changes to occur. Most of these facilities - uranium enrichment plants, weapons assembly plants, research and production reactors, and fuel recycling facilities - are dormant, though periodic inspection, surveillance and maintenance activities within them are on-going. DOE estimates that there are over 5000 buildings that require deactivation to reduce the costs of performing such work with manual labor. In the long term, 1200 buildings will be decommissioned, and millions of metric tons of metal and concrete will have to be recycled or disposed of. The magnitude of the problem calls for new approaches that are far more cost effective than currently available techniques. This paper describes a mobile workstation termed ROSIE, which provides remote work capabilities for D&D activities.

  13. Emergency Facilities and Equipment

    Directives, Delegations, and Requirements [Office of Management (MA)]

    1997-08-21

    This volume clarifies requirements of DOE O 151.1 to ensure that emergency facilities and equipment are considered as part of emergency management program and that activities conducted at these emergency facilities are fully integrated. Canceled by DOE G 151.1-4.

  14. Kauai Test Facility

    SciTech Connect (OSTI)

    Hay, R.G.

    1982-01-01

    The Kauai Test Facility (KTF) is a Department of Energy rocket launch facility operated by Sandia National Laboratories. Originally it was constructed in support of the high altitude atmospheric nuclear test phase of operation Dominic in the early 1960's. Later, the facility went through extensive improvement and modernization to become an integral part of the Safeguard C readiness to resume nuclear testing program. Since its inception and build up, in the decade of the sixties and the subsequent upgrades of the seventies, range test activities have shifted from full scale test to emphasis on research and development of materials and components, and to making high altitude scientific measurements. Primarily, the facility is intended to be utilized in support of development programs at the DOE weapons laboratories, however, other organizations may make use of the facility on a non-interface basis. The physical components at KTF and their operation are described.

  15. Facility deactivation and demolition

    SciTech Connect (OSTI)

    Cormier, S.L.; Adamowski, S.J.

    1994-12-31

    Today an improperly closed facility can be a liability to its owner, both financially and environmentally. A facility deactivation program must be planned and implemented to decrease liabilities, minimize operating costs, seek to reuse or sell processes or equipment, and ultimately aid in the sale and/or reuse of the facility and property whether or not the building(s) are demolished. These programs should be characterized within the deactivation plan incorporating the following major categories: Utility Usage; Environmental Decontamination; Ongoing Facility Management; Property Management/Real Estate Issues. This paper will outline the many facets of the facility deactivation and demolition programs implemented across the country for clients in the chemical, automotive, transportation, electronic, pharmaceutical, power, natural gas and petroleum industries. Specific emphasis will be placed on sampling and analysis plans, specification preparation, equipment and technologies utilized, ``how clean is clean`` discussions and regulatory guidelines applicable to these issues.

  16. Mobile worksystems for decontamination and decommissioning operations. Final report

    SciTech Connect (OSTI)

    1997-02-01

    This project is an interdisciplinary effort to develop effective mobile worksystems for decontamination and decommissioning (D&D) of facilities within the DOE Nuclear Weapons Complex. These mobile worksystems will be configured to operate within the environmental and logistical constraints of such facilities and to perform a number of work tasks. Our program is designed to produce a mobile worksystem with capabilities and features that are matched to the particular needs of D&D work by evolving the design through a series of technological developments, performance tests and evaluations. The Phase I effort was based on a robot called the Remote Work Vehicle (RWV) that was previously developed by CMU for use in D&D operations at the Three Mile Island Unit 2 Reactor Building basement. During Phase I of this program, the RWV was rehabilitated and upgraded with contemporary control and user interface technologies and used as a testbed for remote D&D operations. We established a close working relationship with the DOE Robotics Technology Development Program (RTDP). In the second phase, we designed and developed a next generation mobile worksystem, called Rosie, and a semi-automatic task space scene analysis system, called Artisan, using guidance from RTDP. Both systems are designed to work with and complement other RTDP D&D technologies to execute selective equipment removal scenarios in which some part of an apparatus is extricated while minimally disturbing the surrounding objects. RTDP has identified selective equipment removal as a timely D&D mission, one that is particularly relevant during the de-activation and de-inventory stages of facility transitioning as a means to reduce the costs and risks associated with subsequent surveillance and monitoring. In the third phase, we tested and demonstrated core capabilities of Rosie and Artisan; we also implemented modifications and enhancements that improve their relevance to DOE`s facility transitioning mission.

  17. Center for Transportation Research: The Road to Mobility Innovation Starts

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

    Here | Argonne National Laboratory Center for Transportation Research: The Road to Mobility Innovation Starts Here Not since the invention of the automobile has the future of transportation held such potential. The Center for Transportation Research at Argonne National Laboratory is blazing the way forward, leading on advanced transportation research and development and contributing expertise, tools and facilities for innovation. PDF icon center_for_transportation_research

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

    DOE PAGES-Beta [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

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

    SciTech Connect (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 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.

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

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    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}.

  2. P-doping-free III-nitride high electron mobility light-emitting diodes and transistors

    SciTech Connect (OSTI)

    Li, Baikui; Tang, Xi; Chen, Kevin J.; Wang, Jiannong

    2014-07-21

    We report that a simple metal-AlGaN/GaN Schottky diode is capable of producing GaN band-edge ultraviolet emission at 3.4?eV at a small forward bias larger than ?2?V at room temperature. Based on the surface states distribution of AlGaN, a mature impact-ionization-induced Fermi-level de-pinning model is proposed to explain the underlying mechanism of the electroluminescence (EL) process. By experimenting with different Schottky metals, Ni/Au and Pt/Au, we demonstrated that this EL phenomenon is a universal property of metal-AlGaN/GaN Schottky diodes. Since this light-emitting Schottky diode shares the same active structure and fabrication processes as the AlGaN/GaN high electron mobility transistors, straight-forward and seamless integration of photonic and electronic functional devices has been demonstrated on doping-free III-nitride heterostructures. Using a semitransparent Schottky drain electrode, an AlGaN/GaN high electron mobility light-emitting transistor is demonstrated.

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

    SciTech Connect (OSTI)

    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.

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

    SciTech Connect (OSTI)

    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.

  5. ARM - SGP Geographic Information By Facility

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

    Geographic Information By Facility SGP Related Links Virtual Tour Facilities and Instruments Central Facility Boundary Facility Extended Facility Intermediate Facility Radiometric Calibration Facility Geographic Information ES&H Guidance Statement Operations Science Field Campaigns Visiting the Site Summer Training SGP Fact Sheet Images Information for Guest Scientists Contacts SGP Geographic Information By Facility Note: BF = Boundary Facility, EF = Extended Facility, and IF = Intermediate

  6. STAR Facility Tritium Accountancy

    SciTech Connect (OSTI)

    R. J. Pawelko; J. P. Sharpe; B. J. Denny

    2007-09-01

    The Safety and Tritium Applied Research (STAR) facility has been established to provide a laboratory infrastructure for the fusion community to study tritium science associated with the development of safe fusion energy and other technologies. STAR is a radiological facility with an administrative total tritium inventory limit of 1.5g (14,429 Ci) [1]. Research studies with moderate tritium quantities and various radionuclides are performed in STAR. Successful operation of the STAR facility requires the ability to receive, inventory, store, dispense tritium to experiments, and to dispose of tritiated waste while accurately monitoring the tritium inventory in the facility. This paper describes tritium accountancy in the STAR facility. A primary accountancy instrument is the tritium Storage and Assay System (SAS): a system designed to receive, assay, store, and dispense tritium to experiments. Presented are the methods used to calibrate and operate the SAS. Accountancy processes utilizing the Tritium Cleanup System (TCS), and the Stack Tritium Monitoring System (STMS) are also discussed. Also presented are the equations used to quantify the amount of tritium being received into the facility, transferred to experiments, and removed from the facility. Finally, the STAR tritium accountability database is discussed.

  7. STAR facility tritium accountancy

    SciTech Connect (OSTI)

    Pawelko, R. J.; Sharpe, J. P.; Denny, B. J.

    2008-07-15

    The Safety and Tritium Applied Research (STAR) facility has been established to provide a laboratory infrastructure for the fusion community to study tritium science associated with the development of safe fusion energy and other technologies. STAR is a radiological facility with an administrative total tritium inventory limit of 1.5 g (14,429 Ci) [1]. Research studies with moderate tritium quantities and various radionuclides are performed in STAR. Successful operation of the STAR facility requires the ability to receive, inventory, store, dispense tritium to experiments, and to dispose of tritiated waste while accurately monitoring the tritium inventory in the facility. This paper describes tritium accountancy in the STAR facility. A primary accountancy instrument is the tritium Storage and Assay System (SAS): a system designed to receive, assay, store, and dispense tritium to experiments. Presented are the methods used to calibrate and operate the SAS. Accountancy processes utilizing the Tritium Cleanup System (TCS), and the Stack Tritium Monitoring System (STMS) are also discussed. Also presented are the equations used to quantify the amount of tritium being received into the facility, transferred to experiments, and removed from the facility. Finally, the STAR tritium accountability database is discussed. (authors)

  8. Nuclear Facilities | Department of Energy

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

    Nuclear Facilities Nuclear Facilities Nuclear Facilities Locator Map Numerical map data points indicate two or more nuclear facilities in the same geographic location. Nuclear Facilities List: Argonne National Laboratory East Tennessee Technology Park Hanford Idaho Site Los Alamos National Laboratory Lawrence Livermore National Laboratory Nevada National Security Site New Brunswick Laboratory Oak Ridge National Laboratory cont. Paducah Pantex Pacific Northwest National Laboratory Portsmouth

  9. ARM - Facility News Article

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

    May 5, 2011 [Facility News] New Aircraft Probes in Action Again Bookmark and Share In March, ARM Aerial Facility scientist Jason Tomlinson met with colleagues at the University of North Dakota to assist in the integration of the probes onto the Citation aircraft and to provide training on the operation of the UHSAS-A (back) and HVPS-3 (front) instruments. In March, ARM Aerial Facility scientist Jason Tomlinson met with colleagues at the University of North Dakota to assist in the integration of

  10. Metal-smelting facility

    SciTech Connect (OSTI)

    Kellogg, D.R.; Mack, J.E.; Thompson, W.T.; Williams, L.C.

    1982-01-01

    Currently there are 90,000 tons of contaminated ferrous and nonferrous scrap metal stored in aboveground scrap yards at the Department of Energy's Uranium Enrichment Facilities in Tennessee, Kentucky, and Ohio. This scrap is primarily contaminated with 100 to 500 ppM uranium at an average enrichment of 1 to 1.5% /sup 235/U. A study was performed that evaluated smelting of the ORGDP metal in a reference facility located at Oak Ridge. The study defined the process systems and baseline requirements, evaluated alternatives to smelting, and provided capital and operating costs for the reference facility. A review of the results and recommendations of this study are presented.

  11. Facility Data Policy

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

    Facility Data Policy About ESnet Our Mission The Network ESnet History Governance & Policies ESnet Policy Board ESCC Acceptable Use Policy Data Privacy Policy Facility Data Policy Career Opportunities ESnet Staff & Org Chart Contact Us Contact Us Technical Assistance: 1 800-33-ESnet (Inside US) 1 800-333-7638 (Inside US) 1 510-486-7600 (Globally) 1 510-486-7607 (Globally) Report Network Problems: trouble@es.net Provide Web Site Feedback: info@es.net Facility Data Policy ESnet Data

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

    DOE PAGES-Beta [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

  13. NREL: Research Facilities Home Page

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

    NREL Research Facilities Here you'll find information about the National Renewable Energy Laboratory's R&D facility and laboratory capabilities. These state-of-the-art facilities...

  14. ARM - Facility News Article

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

    The T-1 telephone lines at the four SGP boundary facilities were replaced with satellite ... greatly reduced the demand for dedicated, high-capacity T-1 data transmission lines. ...

  15. ARM - Facility News Article

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

    5, 2009 Facility News Turning a New Page with Facebook; Are You a Fan? Bookmark and Share Keep up with the ARM Climate Research Facilty via Facebook Keep up with the ARM Climate...

  16. ARM - Facility News Article

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

    held this year in Seattle from January 24-28, scientists are presenting dozens of oral and poster sessions describing their research using data from the user facility. Here...

  17. Summary - WTP Pretreatment Facility

    Office of Environmental Management (EM)

    DOE is Immob site's t facilitie purpos techno Facility to be i The as CTEs, Readin * C * C * W * Tr * U * Pu * W * H * Pl The as require The Ele Site: H roject: W Report Date: M ...

  18. ARM - Facility News Article

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

    September 30, 2009 Facility News Climate Change Lesson Plan Selected for MyHealthySchool.com Bookmark and Share A lesson plan about climate change in the Arctic was selected by ...

  19. ARM Climate Research Facility

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

    World's premier ground-based observations facility advancing climate change research Feature A-OK in Oklahoma: SGP Reconfiguration is Right on Track A-OK in Oklahoma: SGP ...

  20. B Plant facility description

    SciTech Connect (OSTI)

    Chalk, S.E.

    1996-10-04

    Buildings 225B, 272B, 282B, 282BA, and 294B were removed from the B Plant facility description. Minor corrections were made for tank sizes and hazardous and toxic inventories.

  1. NETL - Fuel Reforming Facilities

    ScienceCinema (OSTI)

    None

    2016-07-12

    Research using NETL's Fuel Reforming Facilities explores catalytic issues inherent in fossil-energy related applications, including catalyst synthesis and characterization, reaction kinetics, catalyst activity and selectivity, catalyst deactivation, and stability.

  2. ARM - Facility News Article

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

    March 31, 2008 Facility News Interagency Land Use Agreement Signed for North Slope of Alaska Bookmark and Share As scientific neighbors on Alaska's North Slope, the ARM site at...

  3. ARM - Facility News Article

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

    November 8, 2008 Facility News See ARM Data in a New Light Bookmark and Share Two new visualization tools are now available from the ARM Data Archive to help you plot and package...

  4. ARM - Facility News Article

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

    group photo near the ARM millimeter wave cloud radar at the SGP Central Facility. Mike Jensen, principle investigator for the campaign, is second from left. Photo courtesy of Brad...

  5. ARM - Facility News Article

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

    An eleven member Science Board, chaired by Dr. Chris Duffy, Penn State University, has been selected to serve as an independent review body for the ARM Climate Research Facility ...

  6. ARM - Facility News Article

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

    31, 2010 Facility News Instruments on Mt. Pico to Supplement Measurements from Graciosa Island Bookmark and Share At an elevation of about 2225 meters-usually above the marine...

  7. ARM - Facility News Article

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

    the meeting. Visitors from as far away as Tibet, Korea, and Tasmania visited the ARM booth. Most visitors were interested in learning about the scope of the user facility, the...

  8. ARM - Facility News Article

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

    30, 2006 Facility News Precipitation Sensor on Duty at North Slope of Alaska Bookmark and Share The precipitation sensor was installed about 5 feet above the surface on the...

  9. ARM - Facility News Article

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

    Water Vapor Network at SGP Site Goes Offline Bookmark and Share Each of the 24 solar-powered GPS stations streamed data via a wireless network to the SGP Central Facility for data ...

  10. ARM - Facility News Article

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

    to look at the science programs currently in place in Barrow, and to tour a proposed hospital site and the new Barrow Global Climate Change Research Facility currently under...

  11. ARM - Facility News Article

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

    2, 2006 Facility News New NSA Site Manager Named; Science Liaison Joins the Team Bookmark and Share Dr. Mark Ivey to be NSA Site Manager beginning October 1. As of October 1, Dr. ...

  12. ARM - Facility News Article

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

    May 11, 2012 Education, Facility News Fairbanks Middle Schoolers Enjoy Field Trip to Barrow Bookmark and Share Watershed School's bundled-up 8th grade class and their chaperones...

  13. ARM - Facility News Article

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

    March 31, 2007 Facility News Radiometers Operate in Low Water Vapor Conditions in Barrow, Alaska Bookmark and Share A researcher checks the GVR antennae on a cold, crisp day at...

  14. Photovoltaic Research Facilities

    Office of Energy Efficiency and Renewable Energy (EERE)

    The U.S. Department of Energy (DOE) funds photovoltaic (PV) research and development (R&D) at its national laboratory facilities located throughout the country. To encourage further innovation,...

  15. ARM - Facility News Article

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

    August 31, 2009 Facility News North Slope Operations Get a Big Lift Bookmark and Share Operations capabilities at the ARM site in Barrow now include a telehandler that can...

  16. ARM - Facility News Article

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

    February 29, 2008 Facility News Radar Focus Group Zeroes in on Data Quality Bookmark and Share On the roof of the radar instrument shelter at the ARM Southern Great Plains site,...

  17. NETL - Fuel Reforming Facilities

    SciTech Connect (OSTI)

    2013-06-12

    Research using NETL's Fuel Reforming Facilities explores catalytic issues inherent in fossil-energy related applications, including catalyst synthesis and characterization, reaction kinetics, catalyst activity and selectivity, catalyst deactivation, and stability.

  18. ARM - Facility News Article

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

    May 8, 2008 Facility News Cover Combines Images from Arctic Field Campaign Bookmark and Share Cover of the latest report from the U.S. Interagency Arctic Research Policy ...

  19. ARM - Facility News Article

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

    April 15, 2008 Facility News CLASIC Discussed at Workshop in Oklahoma Bookmark and Share ... Studies at the University of Oklahoma hosted a workshop on March 26-27 for ...

  20. ARM - Facility News Article

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

    July 8, 2014 Facility News Studying the Sky-Day and Night Bookmark and Share The Infrared Sky Imager (IRSI) may replace the Total Sky Imager (TSI) for measuring cloud fraction at...

  1. ARM - Facility News Article

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

    30, 2009 Facility News Smart Filter Clears the Way for Speedy Data Transfer Bookmark and Share These data plots illustrate the results of the smart filter in reducing the volume...

  2. ARM - Facility News Article

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

    2, 2014 Facility News First MAGIC Workshop Discusses Future of Marine Clouds Bookmark and Share MAGIC route with June-July-August average low-level cloud cover, GPCI transect,...

  3. ARM - Facility News Article

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

    August 19, 2015 Facility News New ASR Program Manager Selected Bookmark and Share Dr. Shaima Nasiri, ASR Program Manager, U.S. Department of Energy Dr. Shaima Nasiri, ASR Program...

  4. Facility Modernization Report

    SciTech Connect (OSTI)

    Robinson, D; Ackley, R

    2007-05-10

    Modern and technologically up-to-date facilities and systems infrastructure are necessary to accommodate today's research environment. In response, Lawrence Livermore National Laboratory (LLNL) has a continuing commitment to develop and apply effective management models and processes to maintain, modernize, and upgrade its facilities to meet the science and technology mission. The Facility Modernization Pilot Study identifies major subsystems of facilities that are either technically or functionally obsolete, lack adequate capacity and/or capability, or need to be modernized or upgraded to sustain current operations and program mission. This study highlights areas that need improvement, system interdependencies, and how these systems/subsystems operate and function as a total productive unit. Although buildings are 'grandfathered' in and are not required to meet current codes unless there are major upgrades, this study also evaluates compliance with 'current' building, electrical, and other codes. This study also provides an evaluation of the condition and overall general appearance of the structure.

  5. ARM - Facility News Article

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

    1, 2015 Facility News Submit Your AGU Presentation to ARM and ASR Bookmark and Share Submit your AGU presentations or posters by November 2 and we'll help get people to your...

  6. Projects & Facilities - Hanford Site

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

    300 Area 324 Building 325 Building 400 AreaFast Flux Test Facility 618-10 and 618-11 Burial Grounds 700 Area B Plant B Reactor C Reactor Canister Storage Building Canyon ...

  7. ARM - Facility News Article

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

    December 28, 2010 Facility News First Data from Darwin Raman Lidar Bookmark and Share Since 1996, the ARM Southern Great Plains site has maintained one of the few operational...

  8. ARM - Facility News Article

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

    15, 2009 Facility News Internet Upgrade Speeds Data Transfer from Tropics Bookmark and Share http:images.arm.govarmimagesMMCR0MMCR.mpgView this video to see how the...

  9. ARM - Facility News Article

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

    October 6, 2010 Facility News New Raman Lidar En Route to Australia Bookmark and Share Since 1996, the ARM Southern Great Plains site has maintained one of the few operational...

  10. ARM - Facility News Article

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

    file storage needs of the ARM Data Management Facility (DMF) and ARM Engineering computers, a Network Appliance (NetApp) file server with 2.68 terabytes, or 2.95 trillion...

  11. ARM - Facility News Article

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

    8, 2010 Facility News TWP Site Scientist Selected for Journal's Editorial Board Bookmark and Share Dr. Long was recently selected as a member of the editorial board of The Open...

  12. ARM - Facility News Article

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

    13, 2006 Facility News Dr. Steve Ghan Appointed to Journal of Geophysical Research Editorial Board Bookmark and Share Dr. Steve Ghan was recently appointed as an editor for the...

  13. ARM - Facility News Article

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

    to show Bamzai, her husband, and daughter around the site. From the warmth of the crew cab pickup, they toured the Central Facility, which is the heart of the SGP site, not to...

  14. ARM - Facility News Article

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

    October 15, 2007 Facility News Kelle Smith Replaces Jan Gunter as ExtraView Administrator Bookmark and Share Kelle Smith assumed the duties of ExtraView administrator after Jan ...

  15. ARM - Facility News Article

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

    6, 2015 [Facility News] Calling All Data Archive Users Bookmark and Share DataArchive You will need to update your ARM data profile as soon as possible as part of new government reporting requirements. Researchers access data collected through the routine operations and scientific field experiments of the ARM Facility through the ARM Data Archive. An updated registration form requests information about the scientific project for which you are using ARM data. This information is a new requirement

  16. ARM - Facility News Article

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

    10, 2016 [Facility News, Publications] ACME/ARM/ASR, or AAA, Workshop Report Available on DOE Website Bookmark and Share CESD_Report_2016_ACME.indd While the U.S. Department of Energy's (DOE's) Atmospheric Radiation Measurement (ARM) Climate Research Facility and Atmospheric System Research (ASR) and Earth System Modeling (ESM) programs have made considerable contributions to the understanding of the atmospheric component of Earth's climate system and to development and evaluation of global

  17. ARM - Facility News Article

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

    June 20, 2016 [Facility News] Small ARM Campaigns Do Big Science, and You Could Too Bookmark and Share Next round of deadlines for small campaigns coming up; five recently approved campaigns span from Ascension Island to Mount Bachelor Not every science campaign requires a full deployment of ARM Climate Research Facility equipment; important work can be done with just an instrument or two, or in conjunction with a larger operation. These projects fall under the category of ARM's small campaigns.

  18. ARM - Facility News Article

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

    May 15, 2006 [Facility News] New Micropulse Lidars to Replace Old Ones; Deployments Begin at SGP Bookmark and Share A representative from Sigma Space Corporation demonstrates the operation of the new micropulse lidar to ARM instrument mentors and site operations technicians. On May 3, the first of seven new and upgraded micropulse lidars (MPLs) was deployed at the ARM Southern Great Plains (SGP) site's Central Facility. These seven identical systems (including one spare) will replace the

  19. ARM - Facility News Article

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

    26, 2010 [Facility News] ARM Science Board Welcomes New Members Bookmark and Share Several new members have joined the ARM Science Board. This eleven-member board is an independent body that reviews proposals for use of the ARM Climate Research Facility. The board is preparing to review the recently received proposals for the FY2012 campaigns and will be meeting in August. Thanks to the following outgoing Science Board members for their service. Dr. Dave Bader, Lawrence Livermore National

  20. ARGONNE LEADERSHIP COMPUTING FACILITY

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

    SCIENCE ARGONNE LEADERSHIP COMPUTING FACILITY On the cover Collapse of spherical cloud with 50,000 bubbles. The generation of microjets directed toward the cloud center causes the formation of cap-like bubble shapes. Image credit: Computational Science and Engineering Laboratory, ETH Zürich, Switzerland ARGONNE LEADERSHIP COMPUTING FACILITY 2016 SCIENCE HIGHLIGHTS 2016 ALCF SCIENCE HIGHLIGHTS 1 TABLE OF CONTENTS 4 About ALCF 5 Science Director's Message 6 Allocation and Application Programs

  1. Programs & User Facilities

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

    Science Programs » Office of Science » Programs & User Facilities Programs & User Facilities Enabling remarkable discoveries, tools that transform our understanding of energy and matter and advance national, economic, and energy security Advanced Scientific Computing Research Applied Mathematics Co-Design Centers Exascale Co-design Center for Materials in Extreme Environments (ExMatEx) Center for Exascale Simulation of Advanced Reactors (CESAR) Center for Exascale Simulation of

  2. ARM - Facility News Article

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

    September 19, 2016 [Facility News] Upcoming Election for ARM User Executive Committee Bookmark and Share Pavlos Kollias, ARM User Executive Committee member (right) Pavlos Kollias, ARM User Executive Committee member (right) Make a Difference: Get Involved Nominations are underway for the ARM Facility's User Executive committee (UEC). The UEC is made up of scientific users of ARM data. Members are selected according to popular vote by the users according to science areas. This year, in addition

  3. Mound facility physical characterization

    SciTech Connect (OSTI)

    Tonne, W.R.; Alexander, B.M.; Cage, M.R.; Hase, E.H.; Schmidt, M.J.; Schneider, J.E.; Slusher, W.; Todd, J.E.

    1993-12-01

    The purpose of this report is to provide a baseline physical characterization of Mound`s facilities as of September 1993. The baseline characterizations are to be used in the development of long-term future use strategy development for the Mound site. This document describes the current missions and alternative future use scenarios for each building. Current mission descriptions cover facility capabilities, physical resources required to support operations, current safety envelope and current status of facilities. Future use scenarios identify potential alternative future uses, facility modifications required for likely use, facility modifications of other uses, changes to safety envelope for the likely use, cleanup criteria for each future use scenario, and disposition of surplus equipment. This Introductory Chapter includes an Executive Summary that contains narrative on the Functional Unit Material Condition, Current Facility Status, Listing of Buildings, Space Plans, Summary of Maintenance Program and Repair Backlog, Environmental Restoration, and Decontamination and Decommissioning Programs. Under Section B, Site Description, is a brief listing of the Site PS Development, as well as Current Utility Sources. Section C contains Site Assumptions. A Maintenance Program Overview, as well as Current Deficiencies, is contained within the Maintenance Program Chapter.

  4. ORP Projects & Facilities - Hanford Site

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

    Facilities Office of River Protection About ORP ORP Projects & Facilities Tank Farms Waste Treatment & Immobilization Plant 222-S Laboratory 242-A Evaporator Newsroom Contracts &...

  5. Facilities | Photosynthetic Antenna Research Center

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

    Facilities Facilities PARC has three laboratories located in Brauer Hall on the Danforth Campus at Washington University in St. Louis. These labs are available to all PARC members...

  6. National Solar Thermal Test Facility

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

    Nuclear Energy Defense Waste Management Programs Advanced Nuclear Energy Nuclear Energy Safety Technologies Facilities Battery Abuse Testing Laboratory Cylindrical Boiling Facility ...

  7. Defense Nuclear Facility Safety Board

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

    8, 2014 Defense Nuclear Facility Safety Board Defense Nuclear Facility Safety Board (DNSFB) Vice Chairwoman Jesse Roberson visited and toured the WIPP site this week. While ...

  8. Mixed Oxide Fuel Fabrication Facility

    National Nuclear Security Administration (NNSA)

    0%2A en Mixed Oxide (MOX) Fuel Fabrication Facility http:nnsa.energy.govfieldofficessavannah-river-field-officemixed-oxide-mox-fuel-fabrication-facility

  9. Beryllium Facilities & Areas - Hanford Site

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

    Controlled Facilities that have been Demolished Outdoor Areas where Beryllium Contamination has been Identified Hanford Projects and Facilities - Descriptions Former Hanford...

  10. Facility Disposition Safety Strategy RM

    Energy.gov [DOE]

    The Facility Disposition Safety Strategy (FDSS) Review Module is a tool that assists DOE federal project review teams in evaluating the adequacy of the facility documentation, preparations or...

  11. National Solar Thermal Test Facility

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

    SunShot Grand Challenge: Regional Test Centers National Solar Thermal Test Facility HomeTag:National Solar Thermal Test Facility Permalink Air Force Research Laboratory Testing ...

  12. Radiological Training for Tritium Facilities

    Energy Savers

    Change Notice No. 2 May 2007 DOE HANDBOOK RADIOLOGICAL TRAINING FOR TRITIUM FACILITIES ... Change Notice 2. Radiological Safety Training for Tritium Facilities ...

  13. National Solar Thermal Test Facility

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

    SunShot Grand Challenge: Regional Test Centers National Solar Thermal Test Facility HomeTag:National Solar Thermal Test Facility Illuminated receiver on top of tower Permalink ...

  14. National Solar Thermal Test Facility

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

    Stationary PowerEnergy Conversion EfficiencySolar EnergyConcentrating Solar Power (CSP)National Solar Thermal Test Facility National Solar Thermal Test Facility admin ...

  15. Facilities | Energy Systems Integration | NREL

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

    Photo of the Hydrogen Infrastructure Testing and Research Facility building, with fuel cell charging stations and vehicles Hydrogen Infrastructure Testing and Research Facility A ...

  16. 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...

  17. 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...

  18. 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 (OSTI)

    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.

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  7. DOE Designated User Facilities | Department of Energy

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

    Designated User Facilities DOE Designated User Facilities DOE Designated User Facilities Sept 30 2015 More Documents & Publications Microsoft Word - DesignatedUserFacilitiesApri...

  8. Ultrafast Laser Facility | Photosynthetic Antenna Research Center

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

    Ultrafast Laser Facility Ultrafast Laser Facility Click for an Overview of the Ultrafast Laser Facility The PARC Ultrafast Laser Facility, under the direction of Associate Director ...

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