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Sample records for gan airport gan

  1. K.K. Gan 1 Summary of Irradiation Activity

    E-Print Network [OSTI]

    Gan, K. K.

    K.K. Gan 1 Summary of Irradiation Activity September 22, 2010 K.K. Gan The Ohio State University with 300 MeV pions in August VCSEL/PIN Irradiation #12;K.K. Gan TWEPP2010 3 array VCSEL driver Chips Irradiation #12;K.K. Gan TWEPP2010 4 Infinicor SX+: participating institution: SMU

  2. GaN based nanorods for solid state lighting

    SciTech Connect (OSTI)

    Li Shunfeng; Waag, Andreas [Institute of Semiconductor Technology, Braunschweig University of Technology, 38106 Braunschweig (Germany)

    2012-04-01

    In recent years, GaN nanorods are emerging as a very promising novel route toward devices for nano-optoelectronics and nano-photonics. In particular, core-shell light emitting devices are thought to be a breakthrough development in solid state lighting, nanorod based LEDs have many potential advantages as compared to their 2 D thin film counterparts. In this paper, we review the recent developments of GaN nanorod growth, characterization, and related device applications based on GaN nanorods. The initial work on GaN nanorod growth focused on catalyst-assisted and catalyst-free statistical growth. The growth condition and growth mechanisms were extensively investigated and discussed. Doping of GaN nanorods, especially p-doping, was found to significantly influence the morphology of GaN nanorods. The large surface of 3 D GaN nanorods induces new optical and electrical properties, which normally can be neglected in layered structures. Recently, more controlled selective area growth of GaN nanorods was realized using patterned substrates both by metalorganic chemical vapor deposition (MOCVD) and by molecular beam epitaxy (MBE). Advanced structures, for example, photonic crystals and DBRs are meanwhile integrated in GaN nanorod structures. Based on the work of growth and characterization of GaN nanorods, GaN nanoLEDs were reported by several groups with different growth and processing methods. Core/shell nanoLED structures were also demonstrated, which could be potentially useful for future high efficient LED structures. In this paper, we will discuss recent developments in GaN nanorod technology, focusing on the potential advantages, but also discussing problems and open questions, which may impose obstacles during the future development of a GaN nanorod based LED technology.

  3. K.K. Gan Transmission Bandwidth 1 Results on Bandwidth Measurement

    E-Print Network [OSTI]

    Gan, K. K.

    K.K. Gan Transmission Bandwidth 1 Results on Bandwidth Measurement April 16, 2008 K.K, Gan The Ohio State University #12;K.K. Gan Transmission Bandwidth 2 Outline Transmission on micro-cables Transmission on TRT micro-cables Transmission on TRT HV micro-coaxs Summary #12;K.K. Gan Transmission

  4. 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.

  5. 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 launches at a rate of eight per day for the duration of the deployment. The increased sonde launches for the entire period matches that of the AMIE-Manus campaign and makes possible a far more robust Variational Analysis forcing data set product for the entire campaign, and thus better capabilities for modeling studies and synergistic research using the data from both AMIE sites.

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

    DOE Patents [OSTI]

    Zhang, Yu; Sun, Qian; Han, Jung

    2015-12-08

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

  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. 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.

  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. Luminescence properties of defects in GaN

    SciTech Connect (OSTI)

    Reshchikov, Michael A.; Morkoc, Hadis [Department of Electrical Engineering and Physics Department, Virginia Commonwealth University, Richmond, Virginia 23284 (United States)

    2005-03-15

    Gallium nitride (GaN) and its allied binaries InN and AIN as well as their ternary compounds have gained an unprecedented attention due to their wide-ranging applications encompassing green, blue, violet, and ultraviolet (UV) emitters and detectors (in photon ranges inaccessible by other semiconductors) and high-power amplifiers. However, even the best of the three binaries, GaN, contains many structural and point defects caused to a large extent by lattice and stacking mismatch with substrates. These defects notably affect the electrical and optical properties of the host material and can seriously degrade the performance and reliability of devices made based on these nitride semiconductors. Even though GaN broke the long-standing paradigm that high density of dislocations precludes acceptable device performance, point defects have taken the center stage as they exacerbate efforts to increase the efficiency of emitters, increase laser operation lifetime, and lead to anomalies in electronic devices. The point defects include native isolated defects (vacancies, interstitial, and antisites), intentional or unintentional impurities, as well as complexes involving different combinations of the isolated defects. Further improvements in device performance and longevity hinge on an in-depth understanding of point defects and their reduction. In this review a comprehensive and critical analysis of point defects in GaN, particularly their manifestation in luminescence, is presented. In addition to a comprehensive analysis of native point defects, the signatures of intentionally and unintentionally introduced impurities are addressed. The review discusses in detail the characteristics and the origin of the major luminescence bands including the ultraviolet, blue, green, yellow, and red bands in undoped GaN. The effects of important group-II impurities, such as Zn and Mg on the photoluminescence of GaN, are treated in detail. Similarly, but to a lesser extent, the effects of other impurities, such as C, Si, H, O, Be, Mn, Cd, etc., on the luminescence properties of GaN are also reviewed. Further, atypical luminescence lines which are tentatively attributed to the surface and structural defects are discussed. The effect of surfaces and surface preparation, particularly wet and dry etching, exposure to UV light in vacuum or controlled gas ambient, annealing, and ion implantation on the characteristics of the defect-related emissions is described.

  11. 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.

  12. Metal contacts on ZnSe and GaN

    SciTech Connect (OSTI)

    Duxstad, K J [Univ. of California, Berkeley, CA (United States). Materials Science and Mineral Engineering

    1997-05-01

    Recently, considerable interest has been focused on the development of blue light emitting materials and devices. The focus has been on GaN and ZnSe, direct band gap semiconductors with bands gaps of 3.4 and 2.6 eV, respectively. To have efficient, reliable devices it is necessary to have thermally and electrically stable Ohmic contacts. This requires knowledge of the metal-semiconductor reaction behavior. To date few studies have investigated this behavior. Much information has accumulated over the years on the behavior of metals on Si and GaAs. This thesis provides new knowledge for the more ionic wide band gap semiconductors. The initial reaction temperatures, first phases formed, and phase stability of Pt, Pd, and Ni on both semiconductors were investigated. The reactions of these metals on ZnSe and GaN are discussed in detail and correlated with predicted behavior. In addition, comparisons are made between these highly ionic semiconductors and Si and GaAs. The trends observed here should also be applicable to other II-VI and III-Nitride semiconductor systems, while the information on phase formation and stability should be useful in the development of contacts for ZnSe and GaN devices.

  13. K.K. Gan 1 Building New Opto-boards by 2012?

    E-Print Network [OSTI]

    Gan, K. K.

    K.K. Gan 1 Building New Opto-boards by 2012? August 3, 2010 K.K. Gan The Ohio State University #12 to fabricate prototype BeO boards by vendor 2 weeks for passive components mounting 2 weeks to fabricate/test new boards 8 weeks to fabricate production BeO boards by vendor 2 weeks for passive components

  14. Inversion of wurtzite GaN(0001) by exposure to V. Ramachandran and R. M. Feenstra

    E-Print Network [OSTI]

    Feenstra, Randall

    in the growth rate of GaN on different crystallographic planes [8], pointing to a surfactant effect of Mg on Ga in these films and the carrier concentration was therefore very low [1,2]; dopant activa- tion can be achieved of Mg at GaN growth temperatures is an issue and dopant in- corporation may be rather inefficient [5

  15. 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.

  16. Chromatin Ionic Atmosphere Analyzed by a Mesoscale Electrostatic Hin Hark Gan

    E-Print Network [OSTI]

    Schlick, Tamar

    Chromatin Ionic Atmosphere Analyzed by a Mesoscale Electrostatic Approach Hin Hark Gan and Tamar an electrostatic model to handle multivalent ions and compute the ionic distribution around a mesoscale chromatin

  17. Millimeter-wave GaN high electron mobility transistors and their integration with silicon electronics

    E-Print Network [OSTI]

    Chung, Jinwook W. (Jinwook Will)

    2011-01-01

    In spite of the great progress in performance achieved during the last few years, GaN high electron mobility transistors (HEMTs) still have several important issues to be solved for millimeter-wave (30 ~ 300 GHz) applications. ...

  18. Porous GaN nanowires synthesized using thermal chemical vapor deposition

    E-Print Network [OSTI]

    Kim, Bongsoo

    nanotube-confined reaction [4], arc discharge [5], laser ablation [6], sublimation [7], pyrolysis [8O3)/ carbons with NH3 produced the large-quantity porous GaN nanowires on the iron (Fe)/nickel (Ni

  19. Light extraction in individual GaN nanowires on Si for LEDs

    E-Print Network [OSTI]

    Zhou, Xiang

    GaN-based nanowires hold great promise for solid state lighting applications because of their waveguiding properties and the ability to grow nonpolar GaN nanowire-based heterostructures, which could lead to increased light ...

  20. 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.

  1. 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 ?m, overcoming significant challenges in lattice mismatch and thermal expansion differences between Si and GaN in the actual epitaxial growth process. Such thick epilayers are crucial for high voltage operation of lateral geometry devices such as Schottky barrier (SB) diodes and high electron mobility transistors (HEMTs). New “Normally-Off” device architectures were demonstrated – for safe operation of power electronics circuits. The trade-offs between lateral and vertical devices were explored, with the conclusion that lateral devices are superior for fundamental thermal reasons, as well as for the demonstration of future generations of monolithic power circuits. As part of the materials and device investigations breakdown mechanisms in GaN-on-Si structures were fully characterized and effective electric field engineering was recognized as critical for achieving even higher voltage operation. Improved device contact technology was demonstrated, including the first gold-free metallizations (to enable processing in CMOS foundries) while maintaining low specific contact resistance needed for high-power operation and 5-order-of magnitude improvement in device leakage currents (essential for high power operation). In addition, initial GaN-on-Si epitaxial growth was performed on 8”/200 mm Si starting substrates.

  2. 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 using optical reflectance and the nucleation density was determined using atomic force microscopy (AFM) and Nomarski microscopy. Dislocation density was measured using X-ray diffraction and AFM after coating the surface with silicon nitride to delineate all dislocation types. The program milestone of producing GaN films with dislocation densities of 1 x 10{sup 8} cm{sup -2} was met by silicon nitride treatment of annealed sapphire followed by the multiple deposition of a low density of GaN nuclei followed by high temperature GaN growth. Details of this growth process and the underlying science are presented in this final report along with problems encountered in this research and recommendations for future work.

  3. Scanning Kelvin probe microscopy of surface electronic structure in GaN grown by hydride vapor phase epitaxy

    E-Print Network [OSTI]

    Yu, Edward T.

    Scanning Kelvin probe microscopy of surface electronic structure in GaN grown by hydride vapor Engineering and Program in Materials Science and Engineering, University of California at San Diego, La Jolla microscopy is used to image surface potential variations in GaN 0001 grown by hydride vapor phase epitaxy

  4. Thermal stability of amorphous GaN1-xAsx alloys A. X. Levander,1,2

    E-Print Network [OSTI]

    Wu, Junqiao

    Thermal stability of amorphous GaN1-xAsx alloys A. X. Levander,1,2 Z. Liliental-Weber,1 R. Broesler-MBE method.10 Theoretical work has pre- dicted that amorphous GaN could be a technologically useful technological potential, es- pecially in solar energy conversion devices. In this letter we investigate

  5. First-principles studies of beryllium doping of GaN Chris G. Van de Walle* and Sukit Limpijumnong

    E-Print Network [OSTI]

    First-principles studies of beryllium doping of GaN Chris G. Van de Walle* and Sukit Limpijumnong Received 12 October 2000; published 8 June 2001 The structural and electronic properties of beryllium acceptors, and between hydrogen and substitutional beryllium. The results for wurtzite GaN are compared

  6. Thermoelectric effects in wurtzite GaN and AlxGa1-xN alloys and Alexander A. Balandin

    E-Print Network [OSTI]

    Thermoelectric effects in wurtzite GaN and AlxGa1-xN alloys Weili Liua and Alexander A. Balandin have investigated theoretically the thermoelectric effects in wurtzite GaN crystals and AlxGa1-xN-based alloys may have some potential as thermoelectric materials at high temperature. It was found

  7. Optimising GaN (1122) hetero-epitaxial templates grown on (1010) sapphire

    E-Print Network [OSTI]

    Pristovsek, Markus; Frentrup, Martin; Han, Yisong; Humphreys, Colin J.

    2015-01-01

    N (112¯2) hetero-epitaxial templates grown on (101¯0) sapphire process was monitored with a two wavelength Laytec EpiTT reflectometer. Two different approaches have been used for the initial GaN buffer. One is a nucleation of GaN islands which were... annealed and overgrown. This approach is described in [2]. The other approach is AlN nucle- ation, which is performed at 5 kPa reactor pressure with a total flow of 21.7 litres/minute. First the re- actor is heated to 1060?C under hydrogen flow and 150 Pa...

  8. Ge doped GaN with controllable high carrier concentration for plasmonic applications

    SciTech Connect (OSTI)

    Kirste, Ronny; Hoffmann, Marc P.; Sachet, Edward; Bobea, Milena; Bryan, Zachary; Bryan, Isaac; Maria, Jon-Paul; Collazo, Ramón; Sitar, Zlatko [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695-7919 (United States)] [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695-7919 (United States); Nenstiel, Christian; Hoffmann, Axel [Institut f?r Festkörperphsyik, TU-Berlin, Hardenbergstrasse 36, 10623 Berlin (Germany)] [Institut f?r Festkörperphsyik, TU-Berlin, Hardenbergstrasse 36, 10623 Berlin (Germany)

    2013-12-09

    Controllable Ge doping in GaN is demonstrated for carrier concentrations of up to 2.4?×?10{sup 20} cm{sup ?3}. Low temperature luminescence spectra from the highly doped samples reveal band gap renormalization and band filling (Burstein-Moss shift) in addition to a sharp transition. Infrared ellipsometry spectra demonstrate the existence of electron plasma with an energy around 3500?cm{sup ?1} and a surface plasma with an energy around 2000?cm{sup ?1}. These findings open possibilities for the application of highly doped GaN for plasmonic devices.

  9. Learning Deep Sigmoid Belief Networks with Data Augmentation Zhe Gan Ricardo Henao David Carlson Lawrence Carin

    E-Print Network [OSTI]

    Carin, Lawrence

    Learning Deep Sigmoid Belief Networks with Data Augmentation Zhe Gan Ricardo Henao David Carlson Abstract Deep directed generative models are devel- oped. The multi-layered model is designed by stacking available datasets: MNIST, Caltech 101 Silhouettes and OCR letters. 1 Introduction The Deep Belief Network

  10. FOURIER COEFFICIENTS OF MODULAR FORMS ON G2 WEE TECK GAN, BENEDICT GROSS AND GORDAN SAVIN

    E-Print Network [OSTI]

    Gan, Wee Teck

    FOURIER COEFFICIENTS OF MODULAR FORMS ON G2 WEE TECK GAN, BENEDICT GROSS AND GORDAN SAVIN Abstract. We develop a theory of Fourier coefficients for modular forms on the split ex- ceptional group G2 on the group SL2(Z) is the wealth of information carried by the Fourier coefficients an(f), for n 0

  11. Atomic-scale studies on the growth of palladium and titanium on GaN(0001)

    E-Print Network [OSTI]

    Castell, Martin

    Atomic-scale studies on the growth of palladium and titanium on GaN(0001) C. No¨renberg a,b,*, M nitride; Palladium; Titanium; Alloys; Epitaxy; Metal­semiconductor interfaces; Nanostructures; Scanning;Here, we have focused on atomic-scale studies of the ini- tial growth stages of palladium and titanium

  12. Importance of strain for green emitters based on (In, Ga)N films of

    E-Print Network [OSTI]

    Ghosh, Sandip

    , adding more In to lower the energy gap of the active layer for obtaining green-light emissionImportance of strain for green emitters based on (In, Ga)N films of non-polar orientation Sandip for obtaining green-light emitting diodes (LED) and lasers in the wavelength range between 520 and 550 nm

  13. 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.

  14. Lattice Protein Folding With Two and Four-Body Statistical Hin Hark Gan,1

    E-Print Network [OSTI]

    Schlick, Tamar

    Lattice Protein Folding With Two and Four-Body Statistical Potentials Hin Hark Gan,1 Alexander/sequence compatibility of proteins,5,6 homology modeling,7 and protein folding simulations.8 ­10 Currently, most structures. Multibody potentials may help improve our understanding of the cooperativity of protein folding

  15. High-Efficiency X-Band MMIC GaN Power Amplifiers Operating as Rectifiers

    E-Print Network [OSTI]

    Popovic, Zoya

    High-Efficiency X-Band MMIC GaN Power Amplifiers Operating as Rectifiers Michael Litchfield, Scott two 10 x 100j.Lm power combined devices. The MMICs exhibit 67% and 56% power added efficiency at VDD a RF-to-DC efficiency of 64%. The output powers of the two MMIC PAs are around 3.2W. In rectifier mode

  16. Design and Experimental Characterization of an Erbium Doped GaN Waveguide

    E-Print Network [OSTI]

    Wang, Qian

    2012-05-31

    ABSTRACT The goal of this research was to develop an optical amplifier based on Erbium doped GaN waveguides, which can be used in the next-generation of planar integrated optic circuits. This thesis started from the basic concepts of fiber optic...

  17. Integrated Circuit Implementation for a GaN HFETs Driver Circuit

    E-Print Network [OSTI]

    Bakos, Jason D.

    @engr.sc.edu Abstract- The paper presents the design of an integrated circuit (IC) for a 10MHz low power-loss driver exploit the advantages of GaN devices, such as superior switching speed and operation in high-power the authors focus on the design of the IC and present preliminary results and considerations. The driver

  18. Room temperature hydrogen detection using Pd-coated GaN nanowires Wantae Lim,1

    E-Print Network [OSTI]

    Ural, Ant

    Room temperature hydrogen detection using Pd-coated GaN nanowires Wantae Lim,1 J. S. Wright,1 B. P vapor deposition were employed as gas sensors for detection of hydrogen at concentrations from 200­1500 ppm in N2 at 300 K. Palladium coating of the wires improved the sensitivity by a factor of up to 11

  19. Geomagnetic observatory GAN Jakub Velimsky K. Chandra Shakar Rao Lars W. Pedersen Ahmed Muslim

    E-Print Network [OSTI]

    Cerveny, Vlastislav

    ´imsk´y et al. (ETH,UK,DTU,NGRI,GMO) Geomagnetic observatory GAN 27.4.2011/KG MFF UK 1 / 16 #12;Participating, Univ. Stuttgart) John Riddick (BGS, retired) Vel´imsk´y et al. (ETH,UK,DTU,NGRI,GMO) Geomagnetic Measurements and Observatory Practice, 1996) Vel´imsk´y et al. (ETH,UK,DTU,NGRI,GMO) Geomagnetic observatory

  20. Excitation cross section of erbium-doped GaN waveguides under 980?nm optical pumping

    E-Print Network [OSTI]

    Hui, Rongqing; Xie, R.; Feng, I.-W.; Sun, Z. Y.; Lin, J. Y.; Jiang, H. X.

    2014-08-04

    Excitation cross section of erbium-doped GaN waveguides is measured to be approximately 2.2×10?21cm2 at 980?nm pumping wavelength. This cross section value is found relatively insensitive to the crystalline quality of ...

  1. High Efficiency m-plane LEDs on Low Defect Density Bulk GaN Substrates

    SciTech Connect (OSTI)

    David, Aurelien

    2012-10-15

    Solid-state lighting is a key technology for reduction of energy consumption in the US and worldwide. In principle, by replacing standard incandescent bulbs and other light sources with sources based on light-emitting diodes (LEDs), ultimate energy efficiency can be achieved. The efficiency of LEDs has improved tremendously over the past two decades, however further progress is required for solid- state lighting to reach its full potential. The ability of an LED at converting electricity to light is quantified by its internal quantum efficiency (IQE). The material of choice for visible LEDs is Gallium Nitride (GaN), which is at the basis of blue-emitting LEDs. A key factor limiting the performance of GaN LEDs is the so-called efficiency droop, whereby the IQE of the LED decreases significantly at high current density. Despite decades of research, efficiency droop remains a major issue. Since high-current operation is necessary for practical lighting applications, reducing droop is a major challenge for the scientific community and the LED industry. Our approach to solving the droop issue is the use of newly available low-defect-density bulk GaN non-polar substrates. In contrast to the standard foreign substrates (sapphire, silicon carbide, silicon) used in the industry, we have employed native bulk GaN substrates with very low defect density, thus ensuring exquisite material quality and high IQE. Whereas all commercial LEDs are grown along the c-plane crystal direction of GaN, we have used m-plane non-polar substrates; these drastically modify the physical properties of the LED and enable a reduction of droop. With this approach, we have demonstrated very high IQE performance and low droop. Our results focused on violet and blue LEDs. For these, we have demonstrated very high peak IQEs and current droops of 6% and 10% respectively (up to a high current density of 200A.cm-2). All these results were obtained under electrical operation. These high IQE and low droop values are in line with the program’s milestones. They demonstrate that bulk non-polar GaN substrates represent a disruptive technology for LED performance. Application of this technology to real-world products is feasible, provided that the cost of GaN substrates is compatible with the market’s requirement.

  2. Synchrotron radiation x-ray topography and defect selective etching analysis of threading dislocations in GaN

    SciTech Connect (OSTI)

    Sintonen, Sakari, E-mail: sakari.sintonen@aalto.fi; Suihkonen, Sami; Jussila, Henri; Tuomi, Turkka O.; Lipsanen, Harri [Department of Micro- and Nanosciences, Aalto University School of Electrical Engineering, 02150 Espoo (Finland); Rudzi?ski, Mariusz [Epitaxy Department, Institute of Electronic Materials Technology, 01-919 Warsaw (Poland); Knetzger, Michael; Meissner, Elke [Fraunhofer Institute for Integrated Systems and Device Technology, 91058 Erlangen (Germany); Danilewsky, Andreas [Kristallographie Institut für Geo- und Umweltnaturwissenschaften, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg (Germany)

    2014-08-28

    The crystal quality of bulk GaN crystals is continuously improving due to advances in GaN growth techniques. Defect characterization of the GaN substrates by conventional methods is impeded by the very low dislocation density and a large scale defect analysis method is needed. White beam synchrotron radiation x-ray topography (SR-XRT) is a rapid and non-destructive technique for dislocation analysis on a large scale. In this study, the defect structure of an ammonothermal c-plane GaN substrate was recorded using SR-XRT and the image contrast caused by the dislocation induced microstrain was simulated. The simulations and experimental observations agree excellently and the SR-XRT image contrasts of mixed and screw dislocations were determined. Apart from a few exceptions, defect selective etching measurements were shown to correspond one to one with the SR-XRT results.

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

    E-Print Network [OSTI]

    Yu, K. M.

    2010-01-01

    Highly Mismatched Crystalline and Amorphous GaN 1-x As xrange of 0.17crystalline outside this region.is long enough to form crystalline lattices with uniform

  4. Band alignment between GaN and ZrO{sub 2} formed by atomic layer deposition

    SciTech Connect (OSTI)

    Ye, Gang; Wang, Hong, E-mail: ewanghong@ntu.edu.sg; Arulkumaran, Subramaniam; Ng, Geok Ing; Li, Yang; Ang, Kian Siong [Novitas, Nanoelectronics Center of Excellence, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Liu, Zhi Hong [Singapore-MIT Alliance for Research and Technology, 1 CREATE Way, Singapore 138602 (Singapore)

    2014-07-14

    The band alignment between Ga-face GaN and atomic-layer-deposited ZrO{sub 2} was investigated using X-ray photoelectron spectroscopy (XPS). The dependence of Ga 3d and Zr 3d core-level positions on the take-off angles indicated upward band bending at GaN surface and potential gradient in ZrO{sub 2} layer. Based on angle-resolved XPS measurements combined with numerical calculations, valence band discontinuity ?E{sub V} of 1?±?0.2?eV and conduction band discontinuity ?E{sub C} of 1.2?±?0.2?eV at ZrO{sub 2}/GaN interface were determined by taking GaN surface band bending and potential gradient in ZrO{sub 2} layer into account.

  5. 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.

  6. Photoluminescence study of the 1.047 eV emission in GaN K. Pressela)

    E-Print Network [OSTI]

    Nabben, Reinhard

    GaN/ AlGaN blue green light emitting diode, which has a much higher quantum efficiency than the SiC blue light emitting diode, became possible.2 Presently the wide bandgap semi- conductor GaN is intensively. Especially the 1.19 eV is very intense. Thus one can think of developing a light emitting diode in the near

  7. Low gap amorphous GaN1-xAsx alloys grown on glass substrate K. M. Yu,1,a

    E-Print Network [OSTI]

    Wu, Junqiao

    absorption coefficient of 105 cm-1 for the amorphous GaN1-xAsx films suggests that relatively thin films-rich GaN1-xAsx Refs. 6­8 and dilute Te-rich ZnOxTe1-x.9 Recently, we overcame the miscibility gap of GaAs fit to the solar spectrum offering the opportunity to design high efficiency multijunction solar cells

  8. 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.

  9. Influence of oxygen in architecting large scale nonpolar GaN nanowires

    E-Print Network [OSTI]

    Patsha, Avinash; Pandian, Ramanathaswamy; Dhara, S

    2015-01-01

    Manipulation of surface architecture of semiconducting nanowires with a control in surface polarity is one of the important objectives for nanowire based electronic and optoelectronic devices for commercialization. We report the growth of exceptionally high structural and optical quality nonpolar GaN nanowires with controlled and uniform surface morphology and size distribution, for large scale production. The role of O contamination (~1-10^5 ppm) in the surface architecture of these nanowires is investigated with the possible mechanism involved. Nonpolar GaN nanowires grown in O rich condition show the inhomogeneous surface morphologies and sizes (50 - 150 nm) while nanowires are having precise sizes of 40(5) nm and uniform surface morphology, for the samples grown in O reduced condition. Relative O contents are estimated using electron energy loss spectroscopy studies. Size-selective growth of uniform nanowires is also demonstrated, in the O reduced condition, using different catalyst sizes. Photoluminescen...

  10. 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 catalyst.

  11. K.K. Gan B Layer Workshop 1 Opto-Link Upgrade

    E-Print Network [OSTI]

    Gan, K. K.

    -Link Working Group/common projects #12;K.K. Gan B Layer Workshop 3 Need New Opto-Link for B Layer? opto current pixel opto-link architecture to take advantage of R&D effort and production experience #12;K: 14 x 1015 1-MeV neq/cm2 2.7 x 1015 p/cm2 or 71 Mrad for 24 GeV protons above estimates include 50

  12. GAnGS: Gather, Authenticate 'n Group Securely Chia-Hsin Owen Chen

    E-Print Network [OSTI]

    Xu, Wenyuan

    in a scalable, secure, and easy to use fashion. In this paper, we propose GAnGS, a protocol for the se- cure Factors This research was supported in part by the iCAST project under grant NSC96-3114-P-001-002-Y from or any of its agencies. Permission to make digital or hard copies of all or part of this work

  13. Optimization of ion-atomic beam source for deposition of GaN ultrathin films

    SciTech Connect (OSTI)

    Mach, Jind?ich, E-mail: mach@fme.vutbr.cz; Kolíbal, Miroslav; Zlámal, Jakub; Voborny, Stanislav; Bartošík, Miroslav; Šikola, Tomáš [Institute of Physical Engineering, Brno University of Technology, Technická 2, 616 69 Brno (Czech Republic); CEITEC BUT, Brno University of Technology, Technická 10, 61669 Brno (Czech Republic); Šamo?il, Tomáš [Institute of Physical Engineering, Brno University of Technology, Technická 2, 616 69 Brno (Czech Republic)

    2014-08-15

    We describe the optimization and application of an ion-atomic beam source for ion-beam-assisted deposition of ultrathin films in ultrahigh vacuum. The device combines an effusion cell and electron-impact ion beam source to produce ultra-low energy (20–200 eV) ion beams and thermal atomic beams simultaneously. The source was equipped with a focusing system of electrostatic electrodes increasing the maximum nitrogen ion current density in the beam of a diameter of ?15 mm by one order of magnitude (j ? 1000 nA/cm{sup 2}). Hence, a successful growth of GaN ultrathin films on Si(111) 7 × 7 substrate surfaces at reasonable times and temperatures significantly lower (RT, 300?°C) than in conventional metalorganic chemical vapor deposition technologies (?1000?°C) was achieved. The chemical composition of these films was characterized in situ by X-ray Photoelectron Spectroscopy and morphology ex situ using Scanning Electron Microscopy. It has been shown that the morphology of GaN layers strongly depends on the relative Ga-N bond concentration in the layers.

  14. 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.

  15. 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.

  16. Time-resolved photoluminescence studies of free and donor-bound exciton in GaN grown by hydride vapor phase epitaxy

    E-Print Network [OSTI]

    Time-resolved photoluminescence studies of free and donor-bound exciton in GaN grown by hydride and Electrical and Computer Engineering and Photonics Center, Boston University, Boston, Massachusetts, 02215 R in unintentionally doped GaN grown by hydride vapor phase epitaxy. Low temperature (4 K), time-integrated PL spectra

  17. Observation of standing waves at steps on the GaN,,0001... pseudo-,,11... surface by scanning tunneling spectroscopy at room temperature

    E-Print Network [OSTI]

    Li, Lian

    Observation of standing waves at steps on the GaN,,0001... pseudo-,,1Ã1... surface by scanning August 2006; published online 25 September 2006 Standing waves formed at steps of the GaN 0001 pseudo- 1, reflected elec- tron waves emerge to interfere with incoming waves to pro- duce standing waves, thus

  18. Selective area growth and characterization of GaN nanocolumns, with and without an InGaN insertion, on semi-polar (11–22) GaN templates

    SciTech Connect (OSTI)

    Bengoechea-Encabo, A.; Albert, S.; Barbagini, F.; Sanchez-Garcia, M. A.; Calleja, E. [ISOM and Departamento de Ingenieria Electronica, ETSI Telecomunicacion, Universidad Politecnica de Madrid, Ciudad Universitaria s/n 28040 Madrid (Spain)] [ISOM and Departamento de Ingenieria Electronica, ETSI Telecomunicacion, Universidad Politecnica de Madrid, Ciudad Universitaria s/n 28040 Madrid (Spain); Zuñiga-Perez, J.; Mierry, P. de [CRHEA-CNRS, 06560 Valbonne (France)] [CRHEA-CNRS, 06560 Valbonne (France); Trampert, A. [Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin (Germany)] [Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin (Germany)

    2013-12-09

    The aim of this work is the selective area growth (SAG) of GaN nanocolumns, with and without an InGaN insertion, by molecular beam epitaxyon semi-polar (11–22) GaN templates. The high density of stacking faults present in the template is strongly reduced after SAG. A dominant sharp photoluminescence emission at 3.473 eV points to high quality strain-free material. When embedding an InGaN insertion into the ordered GaN nanostructures, very homogeneous optical properties are observed, with two emissions originating from different regions of each nanostructure, most likely related to different In contents on different crystallographic planes.

  19. 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.

  20. The impact of nanoperforation on persistent photoconductivity and optical quenching effects in suspended GaN nanomembranes

    SciTech Connect (OSTI)

    Volciuc, Olesea, E-mail: olesea.volciuc@gmail.com [Institute of Solid State Physics, University of Bremen, Bremen 28334 (Germany) [Institute of Solid State Physics, University of Bremen, Bremen 28334 (Germany); National Center for Materials Study and Testing, Technical University of Moldova, Chisinau 2004 (Moldova, Republic of); Braniste, Tudor [National Center for Materials Study and Testing, Technical University of Moldova, Chisinau 2004 (Moldova, Republic of)] [National Center for Materials Study and Testing, Technical University of Moldova, Chisinau 2004 (Moldova, Republic of); Tiginyanu, Ion, E-mail: tiginyanu@asm.md [National Center for Materials Study and Testing, Technical University of Moldova, Chisinau 2004 (Moldova, Republic of) [National Center for Materials Study and Testing, Technical University of Moldova, Chisinau 2004 (Moldova, Republic of); Institute of Electronic Engineering and Nanotechnologies, Academy of Sciences of Moldova, Chisinau 2028 (Moldova, Republic of); Stevens-Kalceff, Marion A. [School of Physics, University of New South Wales, Sydney NSW 2052 (Australia)] [School of Physics, University of New South Wales, Sydney NSW 2052 (Australia); Ebeling, Jakob; Aschenbrenner, Timo; Hommel, Detlef; Gutowski, Jürgen [Institute of Solid State Physics, University of Bremen, Bremen 28334 (Germany)] [Institute of Solid State Physics, University of Bremen, Bremen 28334 (Germany); Ursaki, Veaceslav [Institute of Applied Physics, Academy of Sciences of Moldova, Chisinau 2028 (Moldova, Republic of)] [Institute of Applied Physics, Academy of Sciences of Moldova, Chisinau 2028 (Moldova, Republic of)

    2013-12-09

    We report on fabrication of suspended ?15?nm thick GaN membranes nanoperforated in an ordered fashion using direct writing of negative charges by focused ion beam and subsequent photoelectrochemical etching of GaN epilayers. Both continuous and nanoperforated membranes exhibit persistent photoconductivity (PPC), which can be optically quenched under excitation by 546?nm radiation. Optical quenching of PPC occurs also under relatively intense intrinsic excitation of nanoperforated membranes by 355?nm radiation at T?

  1. US Department of Energy (DOE)/Gosatomnadzor (GAN) of Russia project at the Petersburg Nuclear Physics Institute (PNPI)

    SciTech Connect (OSTI)

    Baranov, I.A.; Konoplev, K.A. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Hauser, G.C. [Sandia National Lab., Albuquerque, NM (United States)] [and others

    1997-08-01

    This paper presents a summary of work accomplished within the scope of the DOE-Gosatomnadzor (GAN) Agreement to reduce vulnerability to theft of direct-use nuclear materials in Russia. The DOE-GAN agreement concerns the Russian Academy of Science B.P. Konstantinov Petersburg Nuclear Physics Institute (PNPI), located 45 kilometers from St. Petersburg. The PNPI operates facilities to research basic nuclear physics. Current world conditions require particular attention to the issue of Material Protection, Control, and Accounting (MPC&A) of nuclear materials. The long-term plan to increase security at the facility is outlined, including training, physical protection upgrades, and material control and accountability. 4 figs.

  2. Nucleation of single GaN nanorods with diameters smaller than 35 nm by molecular beam epitaxy

    SciTech Connect (OSTI)

    Chen, Yen-Ting [Institute of Atomic and Molecular Sciences, Academia Sinica, 10617 Taipei, Taiwan (China) [Institute of Atomic and Molecular Sciences, Academia Sinica, 10617 Taipei, Taiwan (China); Department of Physics, Chemistry and Biology (IFM), Linköping University, S-58183 Linköping (Sweden); Araki, Tsutomu [Department of Electrical and Electronic Engineering, Ritsumeikan University, 525-8577 Shiga (Japan)] [Department of Electrical and Electronic Engineering, Ritsumeikan University, 525-8577 Shiga (Japan); Palisaitis, Justinas; Persson, Per O. Å.; Olof Holtz, Per; Birch, Jens [Department of Physics, Chemistry and Biology (IFM), Linköping University, S-58183 Linköping (Sweden)] [Department of Physics, Chemistry and Biology (IFM), Linköping University, S-58183 Linköping (Sweden); Chen, Li-Chyong [Center for Condensed Matter Sciences, National Taiwan University, 10617 Taipei, Taiwan (China)] [Center for Condensed Matter Sciences, National Taiwan University, 10617 Taipei, Taiwan (China); Chen, Kuei-Hsien [Institute of Atomic and Molecular Sciences, Academia Sinica, 10617 Taipei, Taiwan (China) [Institute of Atomic and Molecular Sciences, Academia Sinica, 10617 Taipei, Taiwan (China); Center for Condensed Matter Sciences, National Taiwan University, 10617 Taipei, Taiwan (China); Nanishi, Yasushi [Global Innovation Research Organization, Ritsumeikan University, 525-8577 Shiga (Japan)] [Global Innovation Research Organization, Ritsumeikan University, 525-8577 Shiga (Japan)

    2013-11-11

    Nucleation mechanism of catalyst-free GaN nanorod grown on Si(111) is investigated by the fabrication of uniform and narrow (<35 nm) nanorods without a pre-defined mask by molecular beam epitaxy. Direct evidences show that the nucleation of GaN nanorods stems from the sidewall of the underlying islands down to the Si(111) substrate, different from commonly reported ones on top of the island directly. Accordingly, the growth and density control of the nanorods is exploited by a “narrow-pass” approach that only narrow nanorod can be grown. The optimal size of surrounding non-nucleation area around single nanorod is estimated as 88 nm.

  3. High temperature electron spin dynamics in bulk cubic GaN: Nanosecond spin lifetimes far above room-temperature

    SciTech Connect (OSTI)

    Buß, J. H.; Schaefer, A.; Hägele, D.; Rudolph, J. [Arbeitsgruppe Spektroskopie der kondensierten Materie, Ruhr-Universität Bochum, Universitätsstraße 150, D-44780 Bochum (Germany); Schupp, T.; As, D. J. [Department of Physics, University of Paderborn, Warburger Str. 100, D-33095 Paderborn (Germany)

    2014-11-03

    The electron spin dynamics in n-doped bulk cubic GaN is investigated for very high temperatures from 293?K up to 500?K by time-resolved Kerr-rotation spectroscopy. We find extraordinarily long spin lifetimes exceeding 1?ns at 500?K. The temperature dependence of the spin relaxation time is in qualitative agreement with predictions of Dyakonov-Perel theory, while the absolute experimental times are an order of magnitude shorter than predicted. Possible reasons for this discrepancy are discussed, including the role of phase mixtures of hexagonal and cubic GaN as well as the impact of localized carriers.

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

    SciTech Connect (OSTI)

    Mamand, S.M., E-mail: soran.mamand@univsul.net [Department of Physics, College of Science, University of Sulaimani, Sulaimanyah, Iraqi Kurdistan (Iraq); Omar, M.S. [Department of Physics, College of Science, University of Salahaddin, Arbil, Iraqi Kurdistan (Iraq)] [Department of Physics, College of Science, University of Salahaddin, Arbil, Iraqi Kurdistan (Iraq); Muhammad, A.J. [Department of Physics, College of Science, University of Kirkuk, Kirkuk (Iraq)] [Department of Physics, College of Science, University of Kirkuk, Kirkuk (Iraq)

    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.

  5. Evaluation of GaN substrates grown in supercritical basic ammonia

    SciTech Connect (OSTI)

    Saito, Makoto; Yamada, Hisashi; Iso, Kenji; Sato, Hitoshi; Hirasawa, Hirohiko; Kamber, Derrick S.; Hashimoto, Tadao; Baars, Steven P. den; Speck, James S.; Nakamura, Shuji [Materials Department, University of California, Santa Barbara, California 93106 (United States)

    2009-02-02

    GaN crystals grown by the basic ammonothermal method were investigated for their use as substrates for device regrowth. X-ray diffraction analysis indicated that the substrates contained multiple grains while secondary ion mass spectroscopy (SIMS) revealed a high concentration of hydrogen, oxygen, and sodium. Despite these drawbacks, the emission from the light emitting diode structures grown by metal organic chemical vapor deposition on both the c-plane and m-plane epitaxial wafers was demonstrated. The SIMS depth profiles showed that the diffusion of the alkali metal from the substrate into the epitaxial film was small, especially in the m-direction.

  6. p-type GaN grown by phase shift epitaxy

    SciTech Connect (OSTI)

    Zhong, M.; Steckl, A. J., E-mail: a.steckl@uc.edu [Department of Electrical Engineering and Computing Systems, University of Cincinnati, Cincinnati, Ohio 45221-0030 (United States); Roberts, J. [Nitronex Corporation, Raleigh, North Carolina 27606 (United States)] [Nitronex Corporation, Raleigh, North Carolina 27606 (United States); Kong, W.; Brown, A. S. [Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708 (United States)] [Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708 (United States)

    2014-01-06

    Phase shift epitaxy (PSE) is a periodic growth scheme, which desynchronizes host material growth process from dopant incorporation, allowing independent optimization. p-type doping of GaN with Mg by PSE is accomplished with molecular beam epitaxy by periodic shutter action (in order to iterate between Ga- and N-rich surface conditions) and by adjusting time delays between dopant and Ga shutters. Optimum PSE growth was obtained by turning on the Mg flux in the N-rich condition. This suppresses Mg self-compensation at high Mg concentration and produces fairly high hole concentrations (2.4?×?10{sup 18}?cm{sup ?3})

  7. Lattice location of implanted $^{147}$Nd and $^{147*}$Pm in GaN using emission channeling

    E-Print Network [OSTI]

    De Vries, B; Vantomme, A; Correia, J G

    2003-01-01

    The lattice location of $^{147}$Nd and $^{147^{*}}$Pm in thin-film, single-crystalline hexagonal GaN was studied by means of the emission channeling technique. The angular emission yields of $\\beta^{-}$-particles and conversion electrons emitted by the radioactive isotopes $^{147}$Nd and $^{147^{*}}$Pm were measured using a position-sensitive detector following 60 keV room temperature implantation at a dose of 1 $\\times 10^{13}$ cm$^{-2}$ and annealing at 900°C. The emission patterns around the [0001], [1102], [1101], and [2113] crystal axes give direct evidence that the majority (70%) of Nd and Pm atoms occupy substitutional Ga sites.

  8. 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.

  9. Stimulated Emission from As-grown GaN Hexagons by Selective Area Growth Hydride Vapor Phase Epitaxy

    E-Print Network [OSTI]

    Stimulated Emission from As-grown GaN Hexagons by Selective Area Growth Hydride Vapor Phase Epitaxy Engineering and the Photonics Center, Boston University, 8 Saint Mary's St., Boston, MA 02215-2421, USA R hydride vapor phase epitaxy. We found the threshold for bulk stimulated emission to be 3.4 MW cm2

  10. 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 concert with sophisticated molecular-dynamics calculations of surface and defect-mediated NW thermal transport. This proposal seeks to elucidate long standing material science questions for GaN while addressing issues critical to realizing reliable GaN NW devices.

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

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

    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 9×10²? cm?³. Tellurium incorporation resulted in n-doping of GaN1-xAsx layers with Hall carrier concentrations up to 3×10¹? 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

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

    DOE Patents [OSTI]

    Bourret-Courchesne, Edith D. (Richmond, CA)

    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.

  17. 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.

  18. X-Band MMIC GaN Power Amplifiers Designed for High-Efficiency Supply-Modulated Transmitters

    E-Print Network [OSTI]

    Popovic, Zoya

    MMICs that utilize 0.15 µm GaN on SiC process technology are presented. Under continuous wave operating. Process Technology and Model The MMICs were fabricated in a 0.15 µm gate length process with an Al are Imax=1.15 A/mm, gm,max=380 mS/mm, and 3.5 V pinch-off at Vds=10 V. Device breakdown voltage exceeds 50

  19. 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 metal–semiconductor–metal (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.

  20. Influence of post-deposition annealing on interfacial properties between GaN and ZrO{sub 2} grown by atomic layer deposition

    SciTech Connect (OSTI)

    Ye, Gang; Wang, Hong, E-mail: ewanghong@ntu.edu.sg; Arulkumaran, Subramaniam; Ng, Geok Ing; Li, Yang; Ang, Kian Siong [Novitas, Nanoelectronics Center of Excellence, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Geok Ng, Serene Lay; Ji, Rong [Data Storage Institute, Agency for Science Technology and Research (A-STAR), 5 Engineering Drive 1, 117608 (Singapore); Liu, Zhi Hong [Singapore-MIT Alliance for Research and Technology, 1 CREATE Way, Singapore 138602 (Singapore)

    2014-10-13

    Influence of post-deposition annealing on interfacial properties related to the formation/annihilation of interfacial GaO{sub x} layer of ZrO{sub 2} grown by atomic layer deposition (ALD) on GaN is studied. ZrO{sub 2} films were annealed in N{sub 2} atmospheres in temperature range of 300?°C to 700?°C and analyzed by X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy. It has been found that Ga-O bond to Ga-N bond area ratio decreases in the samples annealed at temperatures lower than 500?°C, which could be attributed to the thinning of GaO{sub x} layer associated with low surface defect states due to “clean up” effect of ALD-ZrO{sub 2} on GaN. However, further increase in annealing temperature results in deterioration of interface quality, which is evidenced by increase in Ga-O bond to Ga-N bond area ratio and the reduction of Ga-N binding energy.

  1. 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 [Nano-Optoelectronics Research and Technology Laboratory School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Materials Engineering Department, College of Engineering, University of Kufa, Najaf (Iraq); Nano-Optoelectronics Research and Technology Laboratory School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia)

    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.

  2. Low resistance ohmic contacts on wide band-gap GaN M. E. Lin, Z. Ma, F. Y. Huang, Z. F. Fan, L. H. Allen, and H. MorkoG

    E-Print Network [OSTI]

    Allen, Leslie H.

    -beam evaporation onto the GaN substrate, and then thermally annealed in a temperature range from 500 to 900 "C as high temperature/high power electrical devices, there still remains much more work to be done on GaN epilayers, Foresi et aL6 used Al and Au contacts with 575 "C anneal cycle. However, the specific

  3. Modeling of electronic transport in GaN n-i-p junctions Laboratoire de Physique du Solide, Facults Universitaires Notre-Dame de la Paix, Rue de Bruxelles 61,

    E-Print Network [OSTI]

    Mayer, Alexandre

    Modeling of electronic transport in GaN n-i-p junctions A. Mayera) Laboratoire de Physique du) We propose a model and an algorithm for computing the transport properties of GaN n-i-p devices as cold cathodes2,3 or thermoelectric coolers.4­8 For applications as electronic emitters, the idea

  4. 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.

  5. Performance enhancement of GaN metal–semiconductor–metal 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 metal–semiconductor–metal 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.

  6. 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.

  7. Current crowding in GaInN / GaN LEDs grown on insulating substrates X. Guo, E. F. Schubert and J. Jahns

    E-Print Network [OSTI]

    Jahns, Jürgen

    Current crowding in GaInN / GaN LEDs grown on insulating substrates X. Guo, E. F. Schubert and J. Jahns Current crowding in mesa-structure GaInN/GaN light-emitting diodes (LEDs) grown on insulating and a saturation of the optical output power at high injection currents. It is shown that the optical power

  8. Formation of manganese -doped atomic layer in wurtzite GaN Meng Shi, Abhijit Chinchore, Kangkang Wang, Andrada-Oana Mandru, Yinghao Liu et al.

    E-Print Network [OSTI]

    is formulated based on the experimental data, and implications for possible spintronic applications The importance of spintronics in general was emphati- cally described by Wolf et al.,1 while the possibility to fabri- cate room-temperature spintronic devices based on GaN was proposed by Dietl et al.2 The idea

  9. Open-core screw dislocations in GaN epilayers observed by scanning force microscopy and high-resolution transmission electron microscopy

    E-Print Network [OSTI]

    Rohrer, Gregory S.

    -resolution transmission electron microscopy W. Qian, G. S. Rohrer, and M. Skowronski Department of Materials Science. K. Gaskill Laboratory for Advanced Material Synthesis, Naval Research Laboratory, Washington, DC of organometallic vapor phase epitaxy grown -GaN films using high-resolution transmission electron microscopy

  10. High linearity GaN HEMT power amplifier with pre-linearization gate diode Shouxuan Xie, Vamsi Paidi, Sten Heikman, Alessandro Chini,

    E-Print Network [OSTI]

    Long, Stephen I.

    GaN/GaN HEMT technology. In order to obtain high linearity, a pre-linearization gate diode is added. Introduction. Our previously described single-ended Class B power amplifier design using GaN HEMT technology is biased at exactly the pinch off point (Class B configuration) [1]. In order to further improve

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

    Broader source: Energy.gov [DOE]

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

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

    Broader source: Energy.gov [DOE]

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

  13. Novel ethylenediamine-gallium phosphate containing 6-fold coordinated gallium atoms with unusual four equatorial Ga–N bonds

    SciTech Connect (OSTI)

    Torre-Fernández, Laura [Departamentos de Química Física y Analítica y Química Orgánica e Inorgánica, Universidad de Oviedo-CINN, 33006 Oviedo (Spain); Espina, Aránzazu; Khainakov, Sergei A.; Amghouz, Zakariae [Servicios Científico Técnicos, Universidad de Oviedo, 33006 Oviedo (Spain); García, José R. [Departamentos de Química Física y Analítica y Química Orgánica e Inorgánica, Universidad de Oviedo-CINN, 33006 Oviedo (Spain); García-Granda, Santiago, E-mail: sgg@uniovi.es [Departamentos de Química Física y Analítica y Química Orgánica e Inorgánica, Universidad de Oviedo-CINN, 33006 Oviedo (Spain)

    2014-07-01

    A novel ethylenediamine-gallium phosphate, formulated as Ga(H{sub 2}NCH{sub 2}CH{sub 2}NH{sub 2}){sub 2}PO{sub 4}·2H{sub 2}O, was synthesized under hydrothermal conditions. The crystal structure, including hydrogen positions, was determined using single-crystal X-ray diffraction data (monoclinic, a=9.4886(3) Å, b=6.0374(2) Å, c=10.2874(3) Å, and ?=104.226(3)°, space group Pc) and the bulk was characterized by chemical (Ga–P–C–H–N) and thermal analysis (TG–MS and DSC), including activation energy data of its thermo-oxidative degradation, powder X-ray diffraction (PXRD), solid-state nuclear magnetic resonance (SS-NMR) measurements, and transmission electron microscopy (TEM, SAED/NBD, and STEM BF-EDX). The crystal structure is built up of infinite zig-zag chains running along the c-axis, formed by vertex-shared (PO{sub 4}) and (GaO{sub 2}N{sub 4}) polyhedra. The new compound is characterized by unusual four equatorial Ga–N bonds coming from two nonequivalent ethylenediamine molecules and exhibits strong blue emission at 430 nm (?{sub ex}=350 nm) in the solid state at room temperature. - Graphical abstract: Single crystals of a new ethylenediamine-gallium phosphate, Ga(H{sub 2}NCH{sub 2}CH{sub 2}NH{sub 2}){sub 2}PO{sub 4}·2H{sub 2}O, were obtained and the structural features presented. This structure is one of the scarce examples of GaPO with Ga–N bonds reported. - Highlights: • A novel ethylenediamine-gallium phosphate was hydrothermally synthesized. • The new compound is characterized by unusual four equatorial Ga–N bonds. • Void-volume analysis shows cages and channels with sizes ideally suited to accommodate small molecules. • The new compound exhibits strong blue emission.

  14. spe438-20 page 1 Garrison, N.J., Busby, C.J., Gans, P.B., Putirka, K., and Wagner, D.L., 2008, A mantle plume beneath California? The mid-Miocene Lovejoy flood basalt, northern

    E-Print Network [OSTI]

    Busby, Cathy

    spe438-20 page 1 1 Garrison, N.J., Busby, C.J., Gans, P.B., Putirka, K., and Wagner, D.L., 2008-Miocene Lovejoy flood basalt, northern California Noah J. Garrison Cathy J. Busby Phillip B. Gans Department basalt. #12;2 Garrison et al. spe438-20 page 2 INTRODUCTION Mid-Miocene volcanism in the northern Sierra

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

    SciTech Connect (OSTI)

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

    2012-10-01

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

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

    SciTech Connect (OSTI)

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

    2014-01-28

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

  17. Mg doping of GaN grown by plasma-assisted molecular beam epitaxy under nitrogen-rich conditions

    SciTech Connect (OSTI)

    Zhang Meng; Bhattacharya, Pallab; Guo Wei; Banerjee, Animesh [Department of Electrical Engineering and Computer Science, Solid-State Electronics Laboratory, University of Michigan, Ann Arbor, Michigan 48109-2122 (United States)

    2010-03-29

    Acceptor doping of GaN with Mg during plasma-assisted molecular beam epitaxy, under N-rich conditions and a relatively high growth temperature of 740 deg. C, was investigated. The p-doping level steadily increases with increasing Mg flux. The highest doping level achieved, determined from Hall measurements, is 2.1x10{sup 18} cm{sup -3}. The corresponding doping efficiency and hole mobility are approx4.9% and 3.7 cm{sup 2}/V s at room temperature. Cross-sectional transmission electron microscopy and photoluminescence measurements confirm good crystalline and optical quality of the Mg-doped layers. An InGaN/GaN quantum dot light emitting diode (lambda{sub peak}=529 nm) with p-GaN contact layers grown under N-rich condition exhibits a low series resistance of 9.8 OMEGA.

  18. Structural properties of free-standing 50 mm diameter GaN waferswith (101_0) orientation grown on LiAlO2

    SciTech Connect (OSTI)

    Jasinski, Jacek; Liliental-Weber, Zuzanna; Maruska, Herbert-Paul; Chai, Bruce H.; Hill, David W.; Chou, Mitch M.C.; Gallagher, John J.; Brown, Stephen

    2005-09-27

    (10{und 1}0) GaN wafers grown on (100) face of {gamma}-LiAlO{sub 2} were studied using transmission electron microscopy. Despite good lattice matching in this heteroepitaxial system, high densities of planar structural defects in the form of stacking faults on the basal plane and networks of boundaries located on prism planes inclined to the layer/substrate interface were present in these GaN layers. In addition, significant numbers of threading dislocations were observed. High-resolution electron microscopy indicates that stacking faults present on the basal plane in these layers are of low-energy intrinsic I1type. This is consistent with diffraction contrast experiments.

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

    SciTech Connect (OSTI)

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

    2014-02-15

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

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

    SciTech Connect (OSTI)

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

    2014-06-07

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

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

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

    Ertem, Mehmed Z. [Brookhaven National Lab. (BNL), Upton, NY (United States); Yale Univ., New Haven, CT (United States); Kharche, Neerav [Brookhaven National Lab. (BNL), Upton, NY (United States); Batista, Victor S. [Yale Univ., New Haven, CT (United States); Hybertsen, Mark S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Tully, John C. [Yale Univ., New Haven, CT (United States); Muckerman, James T. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-04-03

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

  2. Comparative study of GaN mesa etch characteristics in Cl{sub 2} based inductively coupled plasma with Ar and BCl{sub 3} as additive gases

    SciTech Connect (OSTI)

    Rawal, Dipendra Singh, E-mail: dsrawal15@gmail.com; Arora, Henika; Sehgal, Bhupender Kumar; Muralidharan, Rangarajan [Solid State Physics Laboratory, Lucknow Road, Timarpur, Delhi-110054 (India)

    2014-05-15

    GaN thin film etching is investigated and compared for mesa formation in inductively coupled plasma (ICP) of Cl{sub 2} with Ar and BCl{sub 3} gas additives using photoresist mask. Etch characteristics are studied as a function of ICP process parameters, viz., ICP power, radio frequency (RF) power, and chamber pressure at fixed total flow rate. The etch rate at each ICP/RF power is 0.1–0.2??m/min higher for Cl{sub 2}/Ar mixture mainly due to higher Cl dissociation efficiency of Ar additive that readily provides Cl ion/radical for reaction in comparison to Cl{sub 2}/BCl{sub 3} mixture. Cl{sub 2}/Ar mixture also leads to better photoresist mask selectivity. The etch-induced roughness is investigated using atomic force microscopy. Cl{sub 2}/Ar etching has resulted in lower root-mean-square roughness of GaN etched surface in comparison to Cl{sub 2}/BCl{sub 3} etching due to increased Ar ion energy and flux with ICP/RF power that enhances the sputter removal of etch product. The GaN surface damage after etching is also evaluated using room temperature photoluminescence and found to be increasing with ICP/RF power for both the etch chemistries with higher degree of damage in Cl{sub 2}/BCl{sub 3} etching under same condition.

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

    SciTech Connect (OSTI)

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

    2014-12-29

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

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

    SciTech Connect (OSTI)

    Krishnamoorthy, Sriram, E-mail: krishnamoorthy.13@osu.edu, E-mail: rajan@ece.osu.edu; Akyol, Fatih [Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Rajan, Siddharth, E-mail: krishnamoorthy.13@osu.edu, E-mail: rajan@ece.osu.edu [Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43210 (United States)

    2014-10-06

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

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

    SciTech Connect (OSTI)

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

    2013-11-14

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

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

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

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

    2015-03-12

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

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

    SciTech Connect (OSTI)

    Zhuang, Y. D.; Shields, P. A.; Allsopp, D. W. E., E-mail: d.allsopp@bath.ac.uk [Department of Electronic and Electrical Engineering, University of Bath, Bath BA2 7AY (United Kingdom); Bruckbauer, J.; Edwards, P. R.; Martin, R. W. [Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

    2014-11-07

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

  8. Evaluation of growth methods for the heteroepitaxy of non-polar (11-20) GaN on sapphire by MOVPE

    E-Print Network [OSTI]

    Oehler, F.; Sutherland, D.; Zhu, T.; Emery, R.; Badcock, T. J.; Kappers, M. J.; Humphreys, C. J.; Dawson, P.; Oliver, R. A.

    2014-09-16

    interlayer. Keywords: A3 Metalorganic vapor phase epitaxy, B1 Nitrides, A1 Defects, A1 Characterization 1. Introduction Hexagonal gallium nitride (GaN) presents two stable growth directions inclined at 90? angle to the c-direction. Respectively named a... is kept constant at 20 standard litres per minute (SLM) by bal- ancing the flow rates of the carrier gas and NH3. Unless otherwise specified, the total reactor pressure is 100 Torr and H2 is used as the carrier gas. The growth temperatures quoted...

  9. Photoconduction efficiencies and dynamics in GaN nanowires grown by chemical vapor deposition and molecular beam epitaxy: A comparison study

    SciTech Connect (OSTI)

    Chen, R. S. [Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Tsai, H. Y. [Graduate Institute of Electro-Optical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Huang, Y. S. [Graduate Institute of Electro-Optical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Department of Electronic Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Chen, Y. T. [Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan (China); Chen, L. C. [Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan (China); Chen, K. H. [Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan (China); Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan (China)

    2012-09-10

    The normalized gains, which determines the intrinsic photoconduction (PC) efficiencies, have been defined and compared for the gallium nitride (GaN) nanowires (NWs) grown by chemical vapor deposition (CVD) and molecular beam epitaxy (MBE). By excluding the contributions of experimental parameters and under the same light intensity, the CVD-grown GaN NWs exhibit the normalized gain which is near two orders of magnitude higher than that of the MBE-ones. The temperature-dependent time-resolved photocurrent measurement further indicates that the higher photoconduction efficiency in the CVD-GaN NWs is originated from the longer carrier lifetime induced by the higher barrier height ({phi}{sub B} = 160 {+-} 30 mV) of surface band bending. In addition, the experimentally estimated barrier height at 20 {+-} 2 mV for the MBE-GaN NWs, which is much lower than the theoretical value, is inferred to be resulted from the lower density of charged surface states on the non-polar side walls.

  10. Surface energy calculations from Zinc blende (111)/(-1-1-1) to Wurtzite (0001)/(000-1):a study of ZnO and GaN

    E-Print Network [OSTI]

    Zhang, Jingzhao; Tse, Kinfai; Deng, Bei; Xu, Hu; Zhu, Junyi

    2015-01-01

    The accurate absolute surface energies of (0001)/(000-1) surfaces of wurtzite structures are crucial in determining the thin film growth mode of important energy materials. However, the surface energies still remain to be solved due to the intrinsic difficulty of calculating dangling bond energy of asymmetrically bonded surface atoms. In this study, we used a pseudo-hydrogen passivation method to estimate the dangling bond energy and calculate the polar surfaces of ZnO and GaN. The calculations were based on the pseudo chemical potentials obtained from a set of tetrahedral clusters or simple pseudo-molecules, using density functional theory approaches. And the surface energies of (0001)/(000-1) surfaces of wurtzite ZnO and GaN we obtained showed relatively high self-consistencies. A wedge structure calculation with a new bottom surface passivation scheme of group I and group VII elements was also proposed and performed to show converged absolute surface energy of wurtzite ZnO polar surfaces, and the result we...

  11. Total current collapse in High-Voltage GaN MIS-HEMTs induced by Zener trapping D. Jin, J. Joh*, S. Krishnan*, N. Tipirneni*, S. Pendharkar* and J. A. del Alamo

    E-Print Network [OSTI]

    del Alamo, Jesús A.

    observed after OFF-state stress at high voltage. We attribute this to high-field tunneling-induced electron/detrapping dynamics have been extracted. All of our experimental results are consistent with electron trapping insideTotal current collapse in High-Voltage GaN MIS-HEMTs induced by Zener trapping D. Jin, J. Joh*, S

  12. Depth dependence of defect density and stress in GaN grown on SiC Department of Electrical and Computer Engineering, University of Delaware, 140 Evans Hall, Newark,

    E-Print Network [OSTI]

    Holtz, Mark

    of Electrical and Computer Engineering, University of Delaware, 140 Evans Hall, Newark, Delaware 19716 H. Temkin Department of Electrical Engineering, Texas Tech University, Lubbock, Texas 79409 I. Ahmad and M. Holtz 2 107 /cm2 in GaN layer grown by hydride vapor phase epitaxy HVPE on SiC 0001 .16 Despite a number

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

    SciTech Connect (OSTI)

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

    2014-06-07

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

  14. Deep acceptors trapped at threading edge dislocations in GaN J. Elsner 1;2 , R. Jones 1 , M. Haugk 2 , Th. Frauenheim 2 , M.I. Heggie 3 , S.

    E-Print Network [OSTI]

    Jones, Robert

    Deep acceptors trapped at threading edge dislocations in GaN J. Elsner 1;2 , R. Jones 1 , M. Haugk--fold coordinated in a bridge position. V Ga --O N is found to be a deep double accecptor, V Ga --(O N ) 2 is a deep defects are responsible for a deep acceptor level associated with the mid­gap yellow luminescence band. Ga

  15. 10 Gb/s Radiation-Hard VCSEL Array Driver K.K. Gan, P. Buchholz, S. Heidbrink, H. Kagan, R. Kass, J. Moore, D.S. Smith, M. Vogt, M. Ziolkowski

    E-Print Network [OSTI]

    Gan, K. K.

    to enhance the radiation-hardness. Each ASIC contains eight low voltage differential signal (LVDS) receivers10 Gb/s Radiation-Hard VCSEL Array Driver K.K. Gan, P. Buchholz, S. Heidbrink, H. Kagan, R. Kass, JV protons to a dose of 0.92x1015 1-MeV neq/cm2 and remain operational. For the 10 Gb/s VCSEL array driver

  16. * email: nidhi@ece.ucsb.edu phone: +1-805-893-3812 ext 202 Ultra-low contact resistance for Self-aligned HEMT structures on N-polar GaN by MBE

    E-Print Network [OSTI]

    Rodwell, Mark J. W.

    * email: nidhi@ece.ucsb.edu phone: +1-805-893-3812 ext 202 Ultra-low contact resistance for SelfN) are regrown to achieve ultra-low Ohmic contact resistance. All MBE regrowths were done on MOCVD GaN templates of InN. To summarize, ultra-low Ohmic contact resistance of 60 -µm was obtained for a self-aligned devi

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

    SciTech Connect (OSTI)

    Reuters, Benjamin; Finken, M.; Wille, A.; Kalisch, H.; Vescan, A.; Hollaender, B.; Heuken, M.

    2012-11-01

    Quaternary AlInGaN layers were grown on conventional GaN buffer layers on sapphire by metal organic vapour phase epitaxy at different surface temperatures and different reactor pressures with constant precursor flow conditions. A wide range in compositions within 30-62% Al, 5-29% In, and 23-53% Ga was covered, which leads to different strain states from high tensile to high compressive. From high-resolution x-ray diffraction and Rutherford backscattering spectrometry, we determined the compositions, strain states, and crystal quality of the AlInGaN layers. Atomic force microscopy measurements were performed to characterize the surface morphology. A critical strain value for maximum In incorporation near the AlInGaN/GaN interface is presented. For compressively strained layers, In incorporation is limited at the interface as residual strain cannot exceed an empirical critical value of about 1.1%. Relaxation occurs at about 15 nm thickness accompanied by strong In pulling. Tensile strained layers can be grown pseudomorphically up to 70 nm at a strain state of 0.96%. A model for relaxation in compressively strained AlInGaN with virtual discrete sub-layers, which illustrates the gradually changing lattice constant during stress reduction is presented.

  18. ARM - News from the Gan Island Deployment

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Comments?govInstrumentsnoaacrnBarrow, Alaska OutreachCalendar NSA Related Links FacilitiesNewsMedia

  19. Scalable Deep Poisson Factor Analysis for Topic Modeling Zhe Gan ZHE.GAN@DUKE.EDU

    E-Print Network [OSTI]

    Carin, Lawrence

    Dirichlet process (nHDP) (Paisley et al., 2015). The nCRP is limited because it re- quires that each

  20. GaN nanowires show more 3D piezoelectricity than bulk GaN

    E-Print Network [OSTI]

    Espinosa, Horacio D.

    director cds murder nudity soundtrack BBC movie releases footage worth documentary film Blu-rays Blu-ray Ga

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

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach HomeA Better Anode Design to Improve4AJ01) (See22, 2012III ARM Data Discovery Browse

  2. ARM - Field Campaign - ARM MJO Investigation Experiment on Gan Island

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach HomeA Better Anode Design to Improve4AJ01) (See22, 2012III ARM Data DiscoveryIV

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

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformationJesse BergkampCentermillion to localPartnership will aidLSMCELower crude

  4. Airline Passengers' Satisfaction with Airports 

    E-Print Network [OSTI]

    Kim, Hyun Joo

    2012-02-14

    Airports are places where people have the potential to experience either satisfaction or frustration, and marketing and tourism scholars have argued that customer satisfaction is one of the primary goals of airports. However, few studies have...

  5. Congestion delays at hub airports

    E-Print Network [OSTI]

    St. George, Martin J.

    1986-01-01

    A deterministic model was developed to study the effects of inefficient scheduling on flight delays at hub airports. The model bases the delay calculation on published schedule data and on user-defined airport capacities. ...

  6. Philadelphia International Airport Apron Lighting: LED System...

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

    Philadelphia International Airport Apron Lighting: LED System Performance in a Trial Installation Philadelphia International Airport Apron Lighting: LED System Performance in a...

  7. Emergence of secondary airports and dynamics of regional airport systems in the United States

    E-Print Network [OSTI]

    Bonnefoy, Philippe A

    2005-01-01

    With the growing demand for air transportation and limited capacity at major airports, there is a need to increase the capacity of airport systems at the metropolitan area level. The increased use of secondary airports has ...

  8. The impact of airline-airport relations on airport management decisions

    E-Print Network [OSTI]

    Cohen, Dayl Arlene

    1985-01-01

    Airlines, in the past, have had an important influence on airport operations through privileges granted them by the airport lease agreements. Airport administrators and sponsoring agencies have agreed to grant these ...

  9. Denver International Airport Photovoltaic System

    Broader source: Energy.gov [DOE]

    The Denver International Airport (DIA) features a 2-megawatt (MW) photovoltaic (PV) system. DIA also hosts to a second 1.6-MW system. Denver is a Solar America City.

  10. Airport Express Tsuen Wan Line

    E-Print Network [OSTI]

    Edward Rd East Lai King Mei Foo Nam Cheong Prince Edward Mongkok Yau Ma Tei Tsim Sha Tsui East International Airport Tsing Yi Ngau Tau Kok Clear Water Bay Road Chek Lap Kok Lung Cheung Rd Prince

  11. Implementing Solar Technologies at Airports

    SciTech Connect (OSTI)

    Kandt, A.; Romero, R.

    2014-07-01

    Federal agencies, such as the Department of Defense and Department of Homeland Security, as well as numerous private entities are actively pursuing the installation of solar technologies to help reduce fossil fuel energy use and associated emissions, meet sustainability goals, and create more robust or reliable operations. One potential approach identified for siting solar technologies is the installation of solar energy technologies at airports and airfields, which present a significant opportunity for hosting solar technologies due to large amounts of open land. This report focuses largely on the Federal Aviation Administration's (FAA's) policies toward siting solar technologies at airports.

  12. Airports and Bicycles: what are the obstacles and incentives for operators 1 to improve bicycle access?

    E-Print Network [OSTI]

    Orrick, Phyllis; Frick, Karen Trapenberg

    2013-01-01

    Bicycle Route to Seattle-Tacoma International Airport andRoute Options to Seattle-Tacoma International Airport.International Airport, Seattle-Tacoma International Airport,

  13. ST. LOUIS AIRPORT/ HAZELWOOD INTERIM

    E-Print Network [OSTI]

    processed at the downtown site from 1942 to 1957 under contracts to the Manhattan Engineering District (MED) and later the Atomic Energy Commission (AEC). The transfer of process residues from downtown to sites nearST. LOUIS AIRPORT/ HAZELWOOD INTERIM STORAGE/FUTURA COATINGS CO. MISSOURI EPA ID# MOD980633176 SITE

  14. Improving public transportation to Boston Logan International Airport

    E-Print Network [OSTI]

    Cao, Siyuan, M. Eng. Massachusetts Institute of Technology

    2013-01-01

    Boston Logan International Airport is the largest airport in New England and the 1 9 th busiest airport in the United States, serving 29.3 million passengers (arrivals and departures) in 2012. There are approximately 36,900 ...

  15. Tackling uncertainty in airport design : a real options approach

    E-Print Network [OSTI]

    Chambers, Richard-Duane

    2007-01-01

    The airport industry is changing. Once understood as stand-alone public infrastructures, many modern airports now operate within privatized multi-airport systems and contend with previously unknown competitive pressures. ...

  16. Siting Solar Photovoltaics at Airports: Preprint

    SciTech Connect (OSTI)

    Kandt, A.; Romero, R.

    2014-06-01

    Airports present a significant opportunity for hosting solar technologies due to their open land; based on a 2010 Federal Aviation Administration study, the US Department of Agriculture, and the US Fish and Wildlife Service, there's potential for 116,704 MW of solar photovoltaics (PV) on idle lands at US airports. PV has a low profile and likely low to no impact on flight operations. This paper outlines guidance for implementing solar technologies at airports and airfields, focusing largely on the Federal Aviation Administration's policies. The paper also details best practices for siting solar at airports, provides information on the Solar Glare Hazard Analysis Tool, and highlights a case study example where solar has been installed at an airport.

  17. Multi-modal Transportation > Highway Transportation > Trucking > Railroad transportation > Public transit > Rural transportation > Rural transit > Freight pipeline transportation > Airport planning and development > Airport maintenance > Bicycle and pedes

    E-Print Network [OSTI]

    and development > Airport maintenance > Bicycle and pedestrian > Ports and waterways >>> Transportation operat and development > Airport maintenance > Bicycle and pedestrian > Ports and waterways >>> Transportation operations pipeline transportation > Airport planning and development > Airport maintenance > Bicycle and pedestrian

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

    SciTech Connect (OSTI)

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

    2014-05-14

    Electrical properties and deep electron and hole traps spectra are compared for undoped n-GaN films grown by hydride vapor phase epitaxy (HVPE) in the regular process (standard HVPE samples) and in HVPE process optimized for decreasing the concentration of residual donor impurities (improved HVPE samples). It is shown that the residual donor density can be reduced by optimization from ?10{sup 17}?cm{sup ?3} to (2–5)?×?10{sup 14}?cm{sup ?3}. The density of deep hole traps and deep electron traps decreases with decreased donor density, so that the concentration of deep hole traps in the improved samples is reduced to ?5?×?10{sup 13}?cm{sup ?3} versus 2.9?×?10{sup 16}?cm{sup ?3} in the standard samples, with a similar decrease in the electron traps concentration.

  19. Negative differential resistance in GaN tunneling hot electron transistors

    SciTech Connect (OSTI)

    Yang, Zhichao; Nath, Digbijoy; Rajan, Siddharth

    2014-11-17

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

  20. Actions as Special Cases Selim T. Erdo gan and Vladimir Lifschitz

    E-Print Network [OSTI]

    Lifschitz, Vladimir

    representation: the design of action description languages and the development of libraries of reusable, general conjecture that a library of standard descriptions for a number of ``basic'' actions can facilitate writing how such a library, writ­ ten in the action language C+, can be used. When using an instance

  1. Optimal Decentralized Protocol for Electric Vehicle Charging Lingwen Gan Ufuk Topcu Steven Low

    E-Print Network [OSTI]

    Low, Steven H.

    is to shift the load due to electric vehicles to fill the overnight electricity demand valley. In each demand is minimized, and the aggregated demand profile is as "flat" as it can possibly be. The proposed energy efficiency, reducing greenhouse gas emissions, and relieving reliance on foreign oil

  2. K.K. Gan 1 Plan for Truelight VCSEL Lifetime Study

    E-Print Network [OSTI]

    Gan, K. K.

    twisted pairs 160 Mb/s data signal in 28 AWG twisted pairs current Type-0 cables use up to 1.4 m calorimeter also die LHCb out straw tracker has ~1% failure (ULM (Philips)) mishandled arrays somehow? thermal stress because array is mounted on FR-4? mechanical stress from optical epoxy covering VCSEL

  3. Materials Data on GaN (SG:225) by Materials Project

    SciTech Connect (OSTI)

    Kristin Persson

    2014-11-02

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  4. Dynamic ON-resistance in high voltage GaN field-effect-transistors

    E-Print Network [OSTI]

    Jin, Donghyun

    2014-01-01

    Recently, the development of energy efficient electrical power management systems has received considerable interest due to its potential to realize significant energy savings for the world. With current Si-based power ...

  5. Min-max Transfer Capability: A New Concept D. Gan X. Luo D. V. Bourcier

    E-Print Network [OSTI]

    a DC load flow setting. A generalization of the algorithm to problems using an AC load flow is briefly, Optimization, Transfer Capability Introduction The notion of the transfer capability of a transmission interface is often used by operators for monitoring transmission system security. Traditionally, the maximum

  6. Deeply-scaled GaN high electron mobility transistors for RF applications

    E-Print Network [OSTI]

    Lee, Dong Seup

    2014-01-01

    Due to the unique combination of large critical breakdown field and high electron velocity, GaN-based high electron mobility transistors (HEMTs) have great potential for next generation high power RF amplifiers. The ...

  7. GaN Nanowire Arrays for High-Output Nanogenerators Chi-Te Huang,,

    E-Print Network [OSTI]

    Wang, Zhong L.

    Although our current energy relies on fossil fuels, searching for nanoenabled sustain- able green energy to be utilized for piezoelectric energy generation with a performance probably better than that of ZnO NWs. Introduction Energy is the fundamental deciding factor for the sustainable development of human civilization.1

  8. Free Carrier Absorption due to Dislocation Scattering in GaN Quantum Wells

    SciTech Connect (OSTI)

    Vaidya, R. G. [Department of Physics, Karnatak University, Dharwad, Karnataka (India); Department of Physics, Tumkur University, Tumkur, Karnataka, 572102 (India); Sankeshwar, N. S.; Mulimani, B. G. [Department of Physics, Karnatak University, Dharwad, Karnataka (India)

    2011-10-20

    Free carrier absorption (FCA) is studied in quantum well structures assuming electrons to be scattered by dislocations via strain field. Expression for FCA coefficient, {alpha} is obtained assuming radiation field to be polarized along the plane of quantum well. Numerical results of {alpha}, as function of photon frequency, {Omega} and well width, d are presented. Calculations show, FCA to decrease with increase in {Omega} with a kink observed at {Omega} = 7.79x10{sup 13} s{sup -1} indicating onset of inter subband transitions. {alpha} is found to be proportional to d{sup -3} and to increase with increase in dislocation density.

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

    SciTech Connect (OSTI)

    Devillers, T. Bonanni, A.; Leite, D. M. G.; Department of Physics, São Paulo State University, Bauru–SP ; Dias da Silva, J. H.

    2013-11-18

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

  10. LiNbO3 thin film growth on (0001)-GaN Peter J. Hansen

    E-Print Network [OSTI]

    York, Robert A.

    generation (SHG) or surface acoustic wave (SAW) filters. The utilization of the polar nature of LiNbO3 has, 1-11-2 Osaki, Shinagawa-ku, Tokyo 141-0032, Japan Yuan Wu Materials Department, University for application in future generation microwave power devices4­6 The extremely high charge density at the Al

  11. 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...

  12. Wirelessly Lockpicking a Smart Card Reader Flavio D. Garcia, Gerhard de Koning Gans, and Roel Verdult

    E-Print Network [OSTI]

    Verdult, Roel

    against iClass Elite (a.k.a., iClass High Security). In order to recover a secret card key, the first system if you are willing to pay a higher price. The iClass Elite Program (a.k.a., High Security) uses

  13. A conductivity-based selective etching for next generation GaN devices

    E-Print Network [OSTI]

    Cao, Hui

    -of-concept demonstrations of photonic and microelectromechanical system (MEMS) device struc- tures facilitated by this new Keywords III­V semiconductors, conductivity, electrochemical etching, microelectromechanical devices the feasibility of novel optical and microelectromechanical system devices. The electrochemical etching exhibited

  14. K.K. Gan Siena02 1 The Ohio State University

    E-Print Network [OSTI]

    Gan, K. K.

    input signal into single-ended signal appropriate to drive VCSEL diode l Output (bright) current: 0 Rise & fall times: 1 ns nominal (80 MHz signals) l Duty cycle: (50 +/- 4)% l "On" voltage of VCSEL: up signal: 40-600 mA l Extract: 40 MHz clock l Duty cycle: (50 +/- 4)% l Total timing error:

  15. Modeling Airline Frequency Competition for Airport Congestion Mitigation

    E-Print Network [OSTI]

    Vaze, Vikrant

    Demand often exceeds capacity at congested airports. Airline frequency competition is partially responsible for the growing demand for airport resources. We propose a game-theoretic model for airline frequency competition ...

  16. Value of Options in Airport Expansion - Example of AICM

    E-Print Network [OSTI]

    Morgado, Frederico

    Investments decisions for airport capacity expansion are usually taken, either when demand exceeds the current capacity and the airport is working under congestion, or when current demand is expected to overcome current ...

  17. Analysis of aircraft surface motion at Boston Logan International Airport

    E-Print Network [OSTI]

    Alhanatis, Robert Elias

    The purpose of this thesis is to examine the nature of aircraft surface motion on the airport surface during normal operations. Twelve hours of radar data, gathered by MIT Lincoln Laboratories from Logan airport in Boston, ...

  18. Of airports and architecture : exercises in public form

    E-Print Network [OSTI]

    Fouad, Daniel James

    2006-01-01

    Airports as an architectural and urban typology typically lack physical and spatial integration with their urban context. Contrary to the city, airports have evolved into semi-autonomous spaces and products of political ...

  19. Airport quotas and peak hour pricing : theory and practice

    E-Print Network [OSTI]

    Odoni, Amedeo R.

    1976-01-01

    This report examines the leading theoretical studies not only of airport peak-hour pricing but also of the congestion costs associated with airport delays and presents a consistent formulation of both. The report also ...

  20. Moriarty Municipal Airport (0E0) Pavement Condition and Analysis

    E-Print Network [OSTI]

    Cal, Mark P.

    Airport Development Administrator New Mexico Aviation Division P.O. Box 9830 Albuquerque, NM 87119 tel .................................................................................................................Skid Resistance 13 ....................................................3. Airport Maintenance Completed Assuming No Maintenance 14 ...............Table 5. Predicted Pavement Conditions (PCI) Assuming

  1. Las Cruces International Airport (LRU) Pavement Condition and Analysis

    E-Print Network [OSTI]

    Cal, Mark P.

    , AICP Airport Development Administrator New Mexico Aviation Division P.O. Box 9830 Albuquerque, NM 87119 ........................................................................................................3. Airport Maintenance 14 .......................................4. Predicted Pavement Conditions Assuming No Maintenance 14 ...............Table 4. Predicted Pavement Conditions (PCI) Assuming

  2. Guidelines to improve airport preparedness against chemical and biological terrorism.

    SciTech Connect (OSTI)

    Edwards, Donna M.; Price, Phillip N. (Lawrence Berkeley National Laboratory, Berkeley, CA); Gordon, Susanna P.; Gadgil, Ashok (Lawrence Berkeley National Laboratory, Berkeley, CA)

    2005-05-01

    Guidelines to Improve Airport Preparedness Against Chemical and Biological Terrorism is a 100-page document that makes concrete recommendations on improving security and assessing vulnerable areas and helps its readers understand the nature of chemical and biological attacks. The report has been turned over to Airports Council International (ACI) and the American Association of Airport Executives (AAAE), two organizations that together represent the interests of thousands of airport personnel and facilities in the U.S. and around the world.

  3. Noise Load Management at Amsterdam Airport Schiphol

    E-Print Network [OSTI]

    Boucherie, Richard J.

    Noise Load Management at Amsterdam Airport Schiphol T.R. Meerburg , R.J. Boucherie , M.J.A.L. van objective is to guarantee safety, efficiency, and protection of the environment, that includes noise load contributes to the noise load at these points. If the cumulative load in an aviation year at an enforce- ment

  4. Airport ATC Communications: Procedures and Phraseology

    E-Print Network [OSTI]

    -four cleared for takeoff · Beech eight-delta-mike, after departure, turn left, and proceed direct to the Boiler runway 24 · ... takeoff from runway 10, turn left after takeoff, and fly direct to the BOILER VOR (pick, cleared to Chicago O'Hare Airport, via direct Boiler, victor-seven Chicago Heights, direct 6. King Air

  5. Evolution and Development of Multi-Airport Systems: A Worldwide Perspective

    E-Print Network [OSTI]

    . This dynamic was driven by the entry of low-cost carriers seizing the opportunity of using existing airport, multi-airport systems have generally evolved through the construction of new high capacity airports, due

  6. EECBG Success Story: New San Antonio Airport Terminal Generating...

    Office of Environmental Management (EM)

    away and the team knew that a solar photovoltaic (PV) system at the airport would offer a highly visible location to showcase renewable energy technologies, help the city...

  7. Vertical Protection Levels for a Local Airport Monitor for WAAS

    E-Print Network [OSTI]

    Stanford University

    they provide acceptable availability, even for a VAL of 10 m. INTRODUCTION The Local Airport Monitor (LAMVertical Protection Levels for a Local Airport Monitor for WAAS Jason Rife, Sam Pullen, Todd Walter development costs for the Local Area Augmentation System (LAAS) have motivated the investigation

  8. FAA Airport Categories Website | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTIONRobertsdale, AlabamaETEC GmbH JumpEllenville,PowerEvaporative CoolersExosunOpenExtremelyFAA Airport

  9. Building Airport Systems for the Next Generation Dealing with the uncertainties of airport development will require new strategies.

    E-Print Network [OSTI]

    Building Airport Systems for the Next Generation Dealing with the uncertainties of airport and passenger buildings, and most travelers know from experience the frequency of aircraft delays, missed skilled and smart people doing their best to make things better, why aren't we getting reasonable results

  10. Decentralized aircraft landing scheduling at single runway non-controlled airports 

    E-Print Network [OSTI]

    Ding, Yuanyuan

    2009-05-15

    to enhance the transportation capabilities of the small airports in the U.S.A., and distribute the high volume of air traffic at the hub airports to those small airports, which are mostly non-controlled airports. Currently, two major focus areas of research...

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

    E-Print Network [OSTI]

    Yu, K. M.

    2010-01-01

    acceptable solar response and efficiency and sufficient5,6] and high efficiency hybrid solar cells [7,8]. Into design high efficiency multijunction solar cells [37,38

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

    SciTech Connect (OSTI)

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

    2013-12-09

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

  13. Magnetic and structural properties of Mn-implanted GaN N. Theodoropoulou and A. F. Hebard

    E-Print Network [OSTI]

    Hebard, Arthur F.

    process- ing, and storage and in photonics. It has been demonstrated in a number of semiconductors, and S. J. Peartona) Department of Materials Science and Engineering, University of Florida, Gainesville hole concentration of 2 1017 cm 3 . Mn ions were implanted at an energy of 250 keV and doses from 1015

  14. Design, characterization, and modeling of GaN based HFETs for millimeter wave and microwave power amplifier applications

    E-Print Network [OSTI]

    Conway, Adam M.

    2006-01-01

    for Microwave and Millimeter-Wave Power Applications,” IEDM.power microwave and millimeter wave power amplifiers. Whilemicrowave and millimeter- wave power amplifier applications.

  15. Doping of GaN12xAsx with high As content A. X. Levander,1,2

    E-Print Network [OSTI]

    Wu, Junqiao

    ,5 Alloying of a-Si has led to multi-junction solar cells with somewhat higher efficiencies, but it also

  16. GaN1-xBix: Extremely mismatched semiconductor alloys A. X. Levander,1,2

    E-Print Network [OSTI]

    Wu, Junqiao

    .1063/1.3499753 Semiconductor alloying is a common method for tailor- ing material properties for specific applicationsGaN1-xBix: Extremely mismatched semiconductor alloys A. X. Levander,1,2 K. M. Yu,1,a S. V. Novikov,3 A. Tseng,1,2 C. T. Foxon,3 O. D. Dubon,1,2 J. Wu,1,2 and W. Walukiewicz1 1 Materials Sciences

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

    E-Print Network [OSTI]

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

  18. "Just to orient us," Dr. Eric Steig be-gan, "Arctic means bear. It is the place

    E-Print Network [OSTI]

    Hart, Gus

    packed the auditorium to capacity to hear Steig discuss his re- search on climate change and Steig, raising waves across the scien- tific community. He is the director of the Quaternary Research Center is ocean and the other is land. The Arctic is covered in sea ice." Data measuring levels of Arctic sea ice

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

    E-Print Network [OSTI]

    Yu, K. M.

    2010-01-01

    makes the fabrication of multijunction cells simple and costhigh efficiency multijunction solar cells [37,38] using a

  20. Simulations of High Linearity and High Efficiency of Class B Power Amplifiers in GaN HEMT Technology

    E-Print Network [OSTI]

    Rodwell, Mark J. W.

    Technology Vamsi Paidi, Shouxuan Xie, Robert Coffie, Umesh K Mishra, Stephen Long, M J W Rodwell Department intermodulation product (IMD3) performance when biased close to the pinch-off voltage. I. Introduction

  1. Transfer passenger needs at airports : human factors in terminal design

    E-Print Network [OSTI]

    Brillembourg, Marie-Claire

    1982-01-01

    This thesis analyzes the needs of particular users of airport: transfer passengers. The object of this work has been to produce a set of design guidelines for terminals. these guidelines are framed upon a user-need survey ...

  2. Hydrogen Production and Dispensing Facility Opens at W. Va. Airport

    Broader source: Energy.gov [DOE]

    A hydrogen production and dispensing station constructed and operated with support from the Office of Fossil Energy's National Energy Technology Laboratory was officially opened Monday at the Yeager Airport in Charleston, W.Va.

  3. A survey of approaches to the airport slot allocation problem

    E-Print Network [OSTI]

    Cohen, Dayl Arlene

    1985-01-01

    Introduction: The allocation of slots at congested major commercial airports is one of the most difficult problems facing the aviation community today. The stakes involved are very large and the controversy generated by ...

  4. New MagViz Airport Liquid Analysis System Undergoes Testing

    ScienceCinema (OSTI)

    None

    2010-01-08

    LOS ALAMOS, New Mexico, December 16, 2008?An innovative application of a technology first used for medical imaging may enhance airport security if Los Alamos National Laboratory scientists are successful. Los Alamos technologists have adapted Magnetic Res

  5. DOE - Office of Legacy Management -- St Louis Airport Site Vicinity...

    Office of Legacy Management (LM)

    been removed from most of the properties and placed in temporary storage at the Hazelwood Interim Storage Site, also known as the Latty Avenue site. The St. Louis Airport Vicinity...

  6. Belen Alexander Municipal Airport (E80) Pavement Condition and Analysis

    E-Print Network [OSTI]

    Cal, Mark P.

    . Lucero, AICP Airport Development Administrator New Mexico Aviation Division P.O. Box 9830 Albuquerque, NM Assuming No Maintenance 13 ..........Table 4. Predicted Pavement Conditions (PCI) Assuming no Maintenance ..............................................................6. Maintenance and Rehabilitation (M&R) Schedule 20

  7. Raton Municipal Airport (RTN) Pavement Condition and Analysis

    E-Print Network [OSTI]

    Cal, Mark P.

    Airport Development Administrator New Mexico Aviation Division P.O. Box 9830 Albuquerque, NM 87119 tel No Maintenance 14 ...............Table 4. Predicted Pavement Conditions (PCI) Assuming no Maintenance After 2007 .......................................................6. Maintenance and Rehabilitation (M&R) Sche

  8. Clayton Municipal Airport (CAO) Pavement Condition and Analysis

    E-Print Network [OSTI]

    Cal, Mark P.

    Airport Development Administrator New Mexico Aviation Division P.O. Box 9830 Albuquerque, NM 87119 tel No Maintenance 13 .....................Table 4. Predicted Pavement Conditions (PCI) Assuming no Maintenance 14 for Runway 12-30 (2010) 20 .......................................................6. Maintenance

  9. Silver City Grant County Airport (SVC) Pavement Condition and Analysis

    E-Print Network [OSTI]

    Cal, Mark P.

    , AICP Airport Development Administrator New Mexico Aviation Division P.O. Box 9830 Albuquerque, NM 87119 No Maintenance 13 ...............Table 4. Predicted Pavement Conditions (PCI) Assuming no Maintenance After 2010 .......................................................6. Maintenance and Rehabilitation (M&R) Schedule 21

  10. Deming Municipal Airport (DMN) Pavement Condition and Analysis

    E-Print Network [OSTI]

    Cal, Mark P.

    Airport Development Administrator New Mexico Aviation Division P.O. Box 9830 Albuquerque, NM 87119 tel No Maintenance 16 2 #12;...............Table 4. Predicted Pavement Conditions (PCI) Assuming no Maintenance After

  11. Sierra Blanca Ruidoso Airport (SRR) Pavement Condition and Analysis

    E-Print Network [OSTI]

    Cal, Mark P.

    , AICP Airport Development Administrator New Mexico Aviation Division P.O. Box 9830 Albuquerque, NM 87119 No Maintenance 13 .................................Table 4. Predicted Pavement Conditions (PCI) Assuming no Maintenance 14 ..........................................Figure 7. Sierra Blanca Ruidoso (SRR) Predicted PCI

  12. Robust decision-support tools for airport surface traffic

    E-Print Network [OSTI]

    Carr, Francis R. (Francis Russell), 1976-

    2004-01-01

    Forecasts of departure demand are one of the driving inputs to tactical decision-support tools (DSTs) for airport surface traffic. While there are well-known results on average- or worst-case forecast uncertainty, it is ...

  13. Robust Decision-Support Tools for Airport Surface Traffic

    E-Print Network [OSTI]

    Carr, Francis R.

    Forecasts of departure demand are one of the driving inputs to tactical decision-support tools (DSTs) for airport surface traffic. While there are well-known results on average- or worst-case forecast uncertainty, it is ...

  14. Roswell International Air Center Airport (ROW) Pavement Condition and Analysis

    E-Print Network [OSTI]

    Cal, Mark P.

    Roswell International Air Center Airport (ROW) Pavement Condition and Analysis Submitted to: Jane M ................................................1. Conditions at Roswell International Air Center (ROW) 4 .................................Figure 1. Geographic Location of Roswell International Air Center (ROW) 4 ..............................Table 1

  15. Mitigating airport congestion : market mechanisms and airline response models

    E-Print Network [OSTI]

    Harsha, Pavithra

    2009-01-01

    Efficient allocation of scarce resources in networks is an important problem worldwide. In this thesis, we focus on resource allocation problems in a network of congested airports. The increasing demand for access to the ...

  16. Airport: Fly into either (SJC) San Jose International Airport (12.2 miles from CHM) or (SFO) San

    E-Print Network [OSTI]

    Geller, Michael R.

    Airport: Fly into either (SJC) San Jose International Airport (12.2 miles from CHM) or (SFO) San.9 miles from CHM) hotel@gardencourt.com Rev: 2/12 San Jose Fairmont Hotel San Jose 170 S. Market Street San Jose, CA 95113 Tel: 408-998-1900 | Fax: 408-287-1648 | Toll free: 866-540-4493 (12.6 miles from

  17. Estimation and tactical allocation of airport capacity in the presence of uncertainty

    E-Print Network [OSTI]

    Ramanujam, Varun

    2012-01-01

    Major airports in the United States and around the world have seen an increase in congestion-related delays over the past few years. Because airport congestion is caused by an imbalance between available capacity and demand, ...

  18. Evaluation of strategies for reducing taxi-out emissions at airports

    E-Print Network [OSTI]

    Deonandan, Indira

    Aircraft taxiing on the surface contribute significantly to the fuel burn and emissions at airports. This paper is aimed at estimating the baseline fuel burn and emissions from taxi-out processes at airports, evaluating ...

  19. Unaffordable fare : the cost of public transportation for low-income commuters working at three airports

    E-Print Network [OSTI]

    Nadeau, Carey Anne

    2015-01-01

    For airport employers, making sure the many low-income people they employ as baggage handlers and retail salespeople, amongst others, can get to work ensures the continued efficient operations of the airport and the ...

  20. A Decision Support Tool for the Pushback Rate Control of Airport Departures

    E-Print Network [OSTI]

    Sandberg, Melanie J.

    Airport surface congestion control has the potential to mitigate the increase in taxi times and fuel burn at major airports. One possible class of congestion control strategies predicts the departure throughput, and ...

  1. Combined Retrieval, Microphysical Retrievals and Heating Rates

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Feng, Zhe

    2013-02-22

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

  2. Combined Retrieval, Microphysical Retrievals and Heating Rates

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Feng, Zhe

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

  3. Determination of two-dimensional electron and hole gas carriers in AlGaN/GaN/AlN heterostructures grown by Metal

    E-Print Network [OSTI]

    Ozbay, Ekmel

    between GaN and a sapphire substrate, the dislocation scattering mechanism and the electron spillover

  4. Double Eagle II Airport (AEG) Pavement Condition and Analysis

    E-Print Network [OSTI]

    Cal, Mark P.

    .........................................................7. Maintenance and Rehabilitation (M&R) Options 21 ...............Table 9. Current NMDOT-Aviation Airport Development Administrator New Mexico Aviation Division P.O. Box 9830 Albuquerque, NM 87119 tel No Maintenance 11 .....................Table 4. Predicted Pavement Conditions (PCI) Assuming no Maintenance 12

  5. Integrating repositories with fuel cycles: The airport authority model

    SciTech Connect (OSTI)

    Forsberg, C. [Massachusetts Inst. of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139-4307 (United States)

    2012-07-01

    The organization of the fuel cycle is a legacy of World War II and the cold war. Fuel cycle facilities were developed and deployed without consideration of the waste management implications. This led to the fuel cycle model of a geological repository site with a single owner, a single function (disposal), and no other facilities on site. Recent studies indicate large economic, safety, repository performance, nonproliferation, and institutional incentives to collocate and integrate all back-end facilities. Site functions could include geological disposal of spent nuclear fuel (SNF) with the option for future retrievability, disposal of other wastes, reprocessing with fuel fabrication, radioisotope production, other facilities that generate significant radioactive wastes, SNF inspection (navy and commercial), and related services such as SNF safeguards equipment testing and training. This implies a site with multiple facilities with different owners sharing some facilities and using common facilities - the repository and SNF receiving. This requires a different repository site institutional structure. We propose development of repository site authorities modeled after airport authorities. Airport authorities manage airports with government-owned runways, collocated or shared public and private airline terminals, commercial and federal military facilities, aircraft maintenance bases, and related operations - all enabled and benefiting the high-value runway asset and access to it via taxi ways. With a repository site authority the high value asset is the repository. The SNF and HLW receiving and storage facilities (equivalent to the airport terminal) serve the repository, any future reprocessing plants, and others with needs for access to SNF and other wastes. Non-public special-built roadways and on-site rail lines (equivalent to taxi ways) connect facilities. Airport authorities are typically chartered by state governments and managed by commissions with members appointed by the state governor, county governments, and city governments. This structure (1) enables state and local governments to work together to maximize job and tax benefits to local communities and the state, (2) provides a mechanism to address local concerns such as airport noise, and (3) creates an institutional structure with large incentives to maximize the value of the common asset, the runway. A repository site authority would have a similar structure and be the local interface to any national waste management authority. (authors)

  6. Airport Modern: The Space between International Departures and Arrivals in Modern Korean National Imaginings

    E-Print Network [OSTI]

    Kim, Alice S.

    2013-01-01

    of National(ist) Journeys: Transcontinental Railroads, theAirport Modern: Transcontinental Railways to Transpacificreplaced colonial-era transcontinental railways in the

  7. Review of EU airport energy interests and priorities with respect to ICT, energy efficiency and enhanced building operation 

    E-Print Network [OSTI]

    Costa, A.; Blanes, L. M.; Donnelly, C.; Keane, M. M.

    2012-01-01

    This paper gives an overview on EU airport energy interests and priorities with respect to ICT, energy efficiency and enhanced building operation. To achieve this objective the paper begins with an overview on airports role on energy consumption...

  8. The Integrated Airport: Building a Successful NextGen Testbed

    ScienceCinema (OSTI)

    Frederick-Recascino, Christina [Embry-Riddle Aeronautical University, Daytona Beach, Florida, United States]; Sweigard, Doug [Lockheed Martin Corporation]; Lester, Wade [ERAU

    2010-01-08

    This presentation will describe a unique public-private partnership - the Integrated Airport - that was created to engage in research and testing related to NextGen Technology deployment.  NextGen refers to the program that will be initiated to modernize the US National Airspace.  As with any major, multi-decade initiative, such as NextGen, integration of work efforts by multiple partners in the modernization is critical for success.  This talk will focus on the development of the consortium, how the consortium plans for NextGen initiatives, the series of technology demonstrations we have produced and plans for the future of NextGen testing and implementation. 

  9. Comprehensive Energy Management and CC® at DFW Airport 

    E-Print Network [OSTI]

    Kramer, L.

    2011-01-01

    Rent-A-Car Center 130,000 2004, 2010 Administration Building 81,000 2007 Terminal D 2,000,000 2008-2009 Energy Plaza (CUP) 41,000 tons of capacity 2008-2009 Terminal E 460,000 2010 North Business Center 52,000 2010 Energy Plaza (HVAC) 125,000 2010... International Airport Continuous Commissioning? International Conference for Enhanced Building Operations New York Marriott at the Brooklyn Bridge New York, NY Larry Kramer, P.E., LC, CEM October 20, 2011 Continuous Commissioning? of DFW International...

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

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O O D S TA I NLoans The Oregon DepartmentAtlanta Airport

  11. Alternative Fuels Data Center: Propane Powers Airport Shuttles in New

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O O D S TA IMarylandOrleans Propane Powers Airport Shuttles

  12. Airport Drive, Missouri: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIX ECoop IncIowaWisconsin: Energy ResourcesAir Quality Jump to:Airforce Wind FarmAirport

  13. Mitigating Runoff Contamination Due to DeIcing and Anti-Icing Operations at T.F.Green Airport

    E-Print Network [OSTI]

    Rhode Island, University of

    for the management of the wastewater that is generated. This responsibility is typically outlined in the airport's discharge permit. In Rhode Island, T.F. Green is the primary of six state airports supervised by the Rhode a solution or solutions to RIAC for TF Green Airport by investigating and analyzing different treatments

  14. Los Alamos Shows Airport Security Technology at Work

    ScienceCinema (OSTI)

    Espy, Michelle; Schultz, Larry; Hunter, James

    2014-06-24

    Los Alamos scientists have advanced a Magnetic Resonance Imaging (MRI) technology that may provide a breakthrough for screening liquids at airport security. They've added low-power X-ray data to the mix, and as a result have unlocked a new detection technology. Funded in part by the Department of Homeland Security's Science and Technology Directorate, the new system is named MagRay. The goal is to quickly and accurately distinguish between liquids that visually appear identical. For example, what appears to be a bottle of white wine could potentially be nitromethane, a liquid that could be used to make an explosive. Both are clear liquids, one would be perfectly safe on a commercial aircraft, the other would be strictly prohibited. How to tell them apart quickly without error at an airport security area is the focus of Michelle Espy, Larry Schultz and their team. In this video, Espy and the MagRay team explain how the new technology works, how they've developed an easy operator interface, and what the next steps might be in transitioning this technology to the private sector.

  15. A major cogeneration system goes in at JFK International Airport. Low-visibility privatization in a high-impact environment

    SciTech Connect (OSTI)

    Leibler, J.; Luxton, R.; Ostberg, P.

    1998-04-01

    This article describes the first major privatization effort to be completed at John F. Kennedy International Airport. The airport owner and operator, the Port Authority of New York and New Jersey, decided to seek private sector involvement in a capital-intensive project to expand and upgrade the airport`s heating and air conditioning facilities and construct a new cogeneration plant. Kennedy International Airport Cogeneration (KIAC) Partners, a partnership between Gas Energy Incorporated of New York and Community Energy Alternatives of New Jersey, was selected to develop an energy center to supply electricity and hot and chilled water to meet the airport`s growing energy demand. Construction of a 110 MW cogeneration plant, 7,000 tons of chilled water equipment, and 30,000 feet of hot water delivery piping started immediately. JFK Airport`s critical international position called for this substantial project to be developed almost invisibly; no interruption in heating and air conditioning service and no interference in the airport`s active operations could be tolerated. Commercial operation was achieved in February 1995.

  16. PHYSICAL REVIEW B 83, 165407 (2011) Two-dimensional Mn structure on the GaN growth surface and evidence for room-temperature

    E-Print Network [OSTI]

    2011-01-01

    Nanotecnolog´ia, Universidad Nacional Aut´onoma de M´exico, Apartado Postal 14, Ensenada Baja California

  17. 90.6% efficient 11MHz 22W LED driver using GaN FETs and burst-mode controller with 0.96 power factor

    E-Print Network [OSTI]

    Chandrakasan, Anantha P.

    With the advent of reliable, high brightness and high efficacy LEDs, the lighting industry is expected to see a significant growth in the near future. However, for LEDs to completely replace the traditional incandescent ...

  18. A Web-Based Platform for Experimental Investigation of Electric Power Auctions Ray D. Zimmerman Robert J. Thomas Deqiang Gan Carlos Murillo-Snchez

    E-Print Network [OSTI]

    electric power markets. The unit commitment problem remains untouched in experimental testing except1 A Web-Based Platform for Experimental Investigation of Electric Power Auctions Ray D. Zimmerman@ee.cornell.edu cem14@cornell.edu School of Electrical Engineering, Cornell University, Ithaca, NY 14853 Abstract

  19. IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS, VOL. 15, NO. 7, JULY 2005 463 A GaN Differential Oscillator With Improved

    E-Print Network [OSTI]

    York, Robert A.

    reported for devices [1], as well as for MMIC amplifiers [2]. A larger voltage across the tank of an os to connect directly to a differential input, such as a balanced mixer in an integrated circuit system per- formance. A design with a fixed tank and without a tail cur- rent source was chosen to help

  20. 3.3 PUBLICATIONS Gan, Z.,W. Wong and J. J. Liou, Semiconductor Process Reliability in Practice, McGraw-Hill,

    E-Print Network [OSTI]

    Pattanaik, Sumanta N.

    . Kutkut, Z.J. Shen and I. Batarseh, "Distributed Battery Micro-storage Systems Design and Operation power- of-two coefficients," Signal Processing, Vol. 92, No. 12, 2012, pp. 2866-2873. 3. Cheng, H. T., S, "Vehicle to Grid Services, Potentials, and Applications," Energies, Vol.5. 2012, pp. 4076-4090. 6. Faiz, J

  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: Nicole.Killat@bristol.ac.uk, E-mail: Martin.Kuball@bristol.ac.uk; Montes Bajo, M.; Kuball, M., E-mail: Nicole.Killat@bristol.ac.uk, E-mail: Martin.Kuball@bristol.ac.uk [Center for Device Thermography and Reliability (CDTR), H.H. Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Paskova, T. [Kyma Technologies, Inc., Raleigh, North Carolina 27617 (United States) [Kyma Technologies, Inc., Raleigh, North Carolina 27617 (United States); Materials Science and Engineering Department, North Carolina State University, Raleigh, North Carolina 27695 (United States); Evans, K. R. [Kyma Technologies, Inc., Raleigh, North Carolina 27617 (United States)] [Kyma Technologies, Inc., Raleigh, North Carolina 27617 (United States); Leach, J. [Kyma Technologies, Inc., Raleigh, North Carolina 27617 (United States) [Kyma Technologies, Inc., Raleigh, North Carolina 27617 (United States); Electrical and Computer Engineering Department, Virginia Commonwealth University, Richmond, Virginia 23284 (United States); Li, X.; Özgür, Ü.; Morkoç, H. [Electrical and Computer Engineering Department, Virginia Commonwealth University, Richmond, Virginia 23284 (United States)] [Electrical and Computer Engineering Department, Virginia Commonwealth University, Richmond, Virginia 23284 (United States); Chabak, K. D.; Crespo, A.; Gillespie, J. K.; Fitch, R.; Kossler, M.; Walker, D. E.; Trejo, M.; Via, G. D.; Blevins, J. D. [Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio 45433 (United States)] [Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio 45433 (United States)

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

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

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

    2011-08-01

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

  3. Journal of Crystal Growth 310 (2008) 23202325 Self-assembled InGaN quantum dots on GaN emitting at 520 nm grown

    E-Print Network [OSTI]

    Gilchrist, James F.

    2008-01-01

    -based blue­green­red LEDs will result in energy-efficient and low-cost approach for the white-light LEDs as the active media for light-emitting diodes (LEDs) and semiconductor laser diodes for green emission. r 2008-emitting diodes (LEDs) to excite the yellow-green and red phosphors, thus resulting in broadband visible white

  4. Importance of excitonic effects and the question of internal electric fields in stacking faults and crystal phase quantum discs: The model-case of GaN

    E-Print Network [OSTI]

    Corfdir, Pierre; Lefebvre, Pierre

    2012-01-01

    are the electron and hole on-axis positions and the in-plane relative coordinate of the exciton, respectively. We assume that the dielectric constant e¼ 9.5e0 is the same in the ZB and WZ layers of the structure.17 me¼ 0.2m018 and mh are the electron and hole... ). 21C. Stampfl and C. G. Van de Walle, Phys. Rev. B 57, R15052 (1998). 22A. Bellabchara, P. Lefebvre, P. Christol, and H. Mathieu, Phys. Rev. B 50, 11840 (1994). 23F. Bernardini, V. Fiorentini, and D. Vanderbilt, Phys. Rev. B 56, R10024 (1997). 24J...

  5. Temperature-Dependence of Exciton Radiative Recombination in (Al,Ga)N/GaN Quantum Wells Grown on a-Plane GaN Substrates

    E-Print Network [OSTI]

    Corfdir, Pierre; Dussaigne, Amélie; Teisseyre, Henryk; Suski, Tadeusz; Grzegory, Izabella; Lefebvre, Pierre; Giraud, Etienne; Shahmohammadi, Mehran; Phillips, Richard; Ganière, Jean-Daniel; Grandjean, Nicolas; Deveaud, Benoît

    -Daniel Ganiere1, Nicolas Grandjean1, and Beno?ˆt Deveaud1 1Institute of Condensed Matter Physics, Ecole Polytechnique Fe´de´rale de Lausanne, 1015 Lausanne, Switzerland 2Cavendish Laboratory, University of Cambridge, CB3 0HE Cambridge, United Kingdom 3Institute... of High Pressure Physics, Polish Academy of Sciences, 01-142 Warsaw, Poland 4Institute of Physics, Polish Academy of Sciences, 02-668 Warsaw, Poland 5CNRS, Laboratoire Charles Coulomb, UMR5221, 34095 Montpellier, France E-mail: pmc53@cam.ac.uk Received...

  6. A COMPUTATIONAL ANALYSIS OF THE OPTIMAL POWER FLOW PROBLEM Baha Alzalg, Catalina Anghel, Wenying Gan, Qing Huang, Mustazee Rahman, Alex Shum

    E-Print Network [OSTI]

    under these contingencies was exemplified by the blackout in the North American power grid during 2003. The reason for the blackout was a failure of only a handful of contingencies in the network [8

  7. LEDs on Semipolar Bulk GaN Substrate with IQE > 80% at 150 A/cm2 and 100ËšC

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious RankADVANCED MANUFACTURING OFFICE INDUSTRIALU.S. DepartmentJeanKeyLANL SustainableRoadway Lighting

  8. Estimation of the economic relationship of an airport to the regional economy : a critical analysis

    E-Print Network [OSTI]

    Fortune, Stephen James

    1981-01-01

    In the past decade many major U.S. airports have encountered extensive opposition to plans for future growth and expansion from environmentalists and community groups who cite the noise and air pollution created and the ...

  9. Airport surface traffic optimization and simulation in the presence of uncertainties

    E-Print Network [OSTI]

    Lee, Hanbong

    2014-01-01

    Surface traffic congestion causes significant taxi delays and long queues for takeoffs at busy airports, increasing operational and environmental costs. These impacts may be mitigated by optimizing runway and taxiway ...

  10. Market-Based Alternatives for Managing Congestion at New York's LaGuardia Airport

    E-Print Network [OSTI]

    representatives and other members of the air transportation community. The first simulation placed participants been used at some airports, such as London Heathrow and Paris Charles de Gaulle, since the early 1970s

  11. Estimating current and future benefits of airport surface congestion management techniques

    E-Print Network [OSTI]

    Nakahara, Alex (Alex Hiroo)

    2012-01-01

    Air traffic is expected to continue to grow in the future and improved methods for dealing with the increased demand on the system need to be designed and implemented. One method for reducing surface congestion at airports ...

  12. Energy, Shading and Daylighting Analysis for the Austin Bergstrom International Airport Terminal 

    E-Print Network [OSTI]

    Holder, L. M. III; Holder, L. M. IV

    2002-01-01

    Our firm was under contract with the City of Austin, Texas to perform energy analysis and analysis of the daylighting potential within the New Austin Bergstrom International Airport Terminal. Design of the Passenger Terminal Facility for the New...

  13. Improved Approach to Lidar Airport Obstruction Surveying Using Full-Waveform Data

    E-Print Network [OSTI]

    Nowak, Robert

    . Parrish1 and Robert D. Nowak2 ABSTRACT Over the past decade, the National Oceanic and Atmospheric, or building that penetrates an airport's obstruction identification surfaces (OIS) (FAA 1996; FAA 2008

  14. A Study on the Effects of Unwanted Air Infiltration on Thermal Comfort at an Airport Terminal 

    E-Print Network [OSTI]

    Lander, B.; Wei, G.; Claridge, D.; Caeiro, J.

    2009-01-01

    the comfort levels that people have become accustomed to in public buildings. Airport terminal buildings, such as the one in this study, built before the current energy awareness that is prevalent today have many problems associated with air infiltration...

  15. DOE to Build Hydrogen Fuel Test Facility at West Virginia Airport

    Broader source: Energy.gov [DOE]

    The Office of Fossil Energy's National Energy Technology Laboratory today announced plans to construct and operate a hydrogen fuel production plant and vehicle fueling station at the Yeager Airport in Charleston, W.Va.

  16. Electronic properties of gallium nitride nanowires

    E-Print Network [OSTI]

    Yoon, Joonah

    2008-01-01

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

  17. Science Highlights 2005

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

    5 Photo: Gan Molecules Defect-Driven Magnetism in Mn-doped GaN DECEMBER 12, 2005 Semiconductors doped with magnetic elements are candidates as room-temperature magnetic...

  18. Public Funding of Airport Incentives: The Efficacy of the Small Community Air Service Development Grant (SCASDG) Program

    E-Print Network [OSTI]

    Wittman, Michael D.

    2014-01-08

    As U.S. airlines began to restrict available domestic capacity at smaller airports in 2008 as a result of higher

  19. October 30, 2013 Status of Opto-Board Production

    E-Print Network [OSTI]

    Gan, K. K.

    Pixel Week 1 October 30, 2013 K.K. Gan Status of Opto-Board Production K.K. Gan, R + 16 data links #12;Pixel Week 3 Production Status K.K. Gan nSQP B opto-boards production completed passed reception test at CERN IBL opto-boards production completed passed

  20. Uranium characterization at the St. Louis Airport Site

    SciTech Connect (OSTI)

    Schilk, A.J.; Hubbard, C.W.; Bowyer, T.W. [Pacific Northwest Lab., Richland, WA (United States); Reiman, R.T. [Technical Measurement Co., Boulder, CO (United States)

    1995-05-01

    In support of the Department of Energy/Office of Technology Development`s Expedited Site Characterization (ESC) project (coordinated by Ames Laboratory), the Pacific Northwest Laboratory demonstrated two complementary technologies at the St. Louis Airport (SLAP) site that have been designed and optimized for the rapid, in situ quantification of radionuclide contamination in surface soils. The sensors are optimized for the detection of high-energy beta particles or gamma rays emitted from the decay of specific radionuclides of interest. These technologies were demonstrated by measuring the beta and gamma fluxes at several locations within the SLAP site. Measurements were converted to average contamination levels, using detector calibrations performed with spiked samples (beta) or sealed sources (gamma). Additionally, subsurface activity levels were derived from discrete soil samples (provided by the ESC field crew) via gamma-ray spectrometry in a controlled laboratory setting. Since the beta and gamma sensor technologies are intrinsically sensitive to different types of radiation and activity distributions (i.e., surface and shallow subsurface, respectively), the data obtained from the two detectors provide complementary information about the distribution of the contamination. The results reported here suggest that a number of locations within the SLAP site have elevated levels of {sup 211}U, and the differences between the beta and gamma activities indicate that the contamination is largely located near the surface of the soil.

  1. ADEPT SCIENTIFIC ENDNOTE LANDESLIZENZ VEREINBARUNG Dies ist eine Vereinbarung zwischen Thomson ResearchSoft mit Hauptsitz in 2141 Palomar Airport Road, Suite 350,

    E-Print Network [OSTI]

    Ott, Albrecht

    ResearchSoft mit Hauptsitz in 2141 Palomar Airport Road, Suite 350, Carlsbad, CA 92009, USA vertreten durch

  2. Paper No. 11.05 1 A Half Century of Tapered-Pile Usage at the John F. Kennedy International Airport

    E-Print Network [OSTI]

    Horvath, John S.

    Paper No. 11.05 1 A Half Century of Tapered-Pile Usage at the John F. Kennedy International Airport. Kennedy International Airport (JFKIA) in New York City began in the late 1940s. Timber piles were used the well-known John F. Kennedy International Airport (JFKIA, originally named New York International

  3. Cost Benefit Analysis Modeling Tool for Electric vs. ICE Airport Ground Support Equipment – Development and Results

    SciTech Connect (OSTI)

    James Francfort; Kevin Morrow; Dimitri Hochard

    2007-02-01

    This report documents efforts to develop a computer tool for modeling the economic payback for comparative airport ground support equipment (GSE) that are propelled by either electric motors or gasoline and diesel engines. The types of GSE modeled are pushback tractors, baggage tractors, and belt loaders. The GSE modeling tool includes an emissions module that estimates the amount of tailpipe emissions saved by replacing internal combustion engine GSE with electric GSE. This report contains modeling assumptions, methodology, a user’s manual, and modeling results. The model was developed based on the operations of two airlines at four United States airports.

  4. STRATEGIC PLANNING FOR AIRPORT CAPACITY: An Appreciation of Australia's Process for Sydney1

    E-Print Network [OSTI]

    1 STRATEGIC PLANNING FOR AIRPORT CAPACITY: An Appreciation of Australia's Process for Sydney1 demonstrating by example the advantages of strategic planning as compared to traditional master planning. Strategic planning recognises that there is massive uncertainty in long-term forecasts, and consequently

  5. A Portable Low-Cost High Density Sensor Network for Air Quality at London Heathrow Airport

    E-Print Network [OSTI]

    Jackson, Sophie

    species: CO, NO, O3, SO2, NO2 (electrochemical (EC) at 2 s) CO2 and total VOCs (optical at 10 s). · Size stations outside LHR (all CO2, sizeA Portable Low-Cost High Density Sensor Network for Air Quality at London Heathrow Airport Olalekan

  6. Problem Statement: Airports need to achieve carbon neutral growth operating an enterprise

    E-Print Network [OSTI]

    for Rental Cars and Commercial Vehicles Convert Rental Cars from Gas to Hybrid 50% Rental Fleet to Hybrid 0. Alternatively Fueled Airport Access Taxis (e.g. Hybrids or Electric vehicles) Inhibiting Factors to Carbon annually) 0.63 17,400 Alternatively Fueled Taxis Convert Taxi Fleet to Hybrid [Control through MWAA

  7. Implementation of alternative bio-based fuels in aviation: The Clean Airports Program

    SciTech Connect (OSTI)

    Shauck, M.E.; Zanin, M.G.

    1997-12-31

    The Renewable Aviation Fuels Development Center at Baylor University in Waco, Texas, was designated, in March 1996, by the US Department of Energy (US DOE) as the national coordinator of the Clean Airports Program. This program, a spin-off of the Clean Cities Program, was initiated to increase the use of alternative fuels in aviation. There are two major fuels used in aviation today, the current piston engine aviation gasoline, and the current turbine engine fuel. The environmental impact of each of these fuels is significant. Aviation Gasoline (100LL), currently used in the General Aviation piston engine fleet, contributes 100% of the emissions containing lead in the USA today. In the case of the turbine engine fuel (Jet fuel), there are two major environmental impacts to be considered: the local, in the vicinity of the airports, and the global impact on climate change. The Clean Airports Program was established to promote the use of clean burning fuels in order to achieve and maintain clean air at and in the vicinities of airports through the use of alternative fuel-powered air and ground transportation vehicles.

  8. PREDICTION OF FOG EPISODES AT THE AIRPORT OF MADRID-BARAJAS USING DIFFERENT MODELING APPROACHES

    E-Print Network [OSTI]

    Politècnica de Catalunya, Universitat

    PREDICTION OF FOG EPISODES AT THE AIRPORT OF MADRID-BARAJAS USING DIFFERENT MODELING APPROACHES Meteorología (INM) has been investigating for some time the phenomena related to the formation of fog episodes between the development of fog and the establishment of katabatic flows in the region, generally under

  9. HumanWildlife Conflicts 2(2):240247, Fall 2008 Mammalian hazards at small airports in

    E-Print Network [OSTI]

    fence maintenance is vital for effective wildlife- strike management at small airports. Key words,000 hours of aircraft downtime each year and cost the civil aviation industry >$556 million annually (Cleary the inception of aviation 100 years ago (Sodhi 2002). Unfortunately, the probability of wildlife strikes

  10. Detection Probability Modeling for Airport Wind-Shear August 28, 2008

    E-Print Network [OSTI]

    Cho, John Y. N.

    Detection Probability Modeling for Airport Wind-Shear Sensors August 28, 2008 John Y. N. Cho Robert An objective wind-shear detection probability estimation model is developed for radar, lidar, and sensor combinations. The model includes effects of system sensitivity, site-specific wind-shear, clutter, and terrain

  11. Directions to the University of Connecticut Storrs Campus From Bradley International Airport

    E-Print Network [OSTI]

    Olshevsky, Vadim

    Directions to the University of Connecticut ­ Storrs Campus From Bradley International Airport on Connecticut Route 195 about 6 miles to the University. (You will come to the intersection of Rt. 195 and Rt of the exit ramp. Travel south on Connecticut Route 195 about 6 miles to the University. (You will come

  12. A Phase I Cultural Resources Survey of the Easterwood Airport Project in Central Brazos County, Texas 

    E-Print Network [OSTI]

    Moore, William

    2015-06-30

    An archaeological survey of 4.2 acre tract at Easterwood Airport in the city limits of College Station, Texas (central Brazos County) was conducted on May 10, 2002 by Brazos Valley Research Associates of Bryan, Texas. The Texas A&M University...

  13. Why some airport-rail links get built and others do not : the role of institutions, equity and financing

    E-Print Network [OSTI]

    Nickel, Julia, S.M. Massachusetts Institute of Technology

    2011-01-01

    The thesis seeks to provide an understanding of reasons for different outcomes of airport ground access projects. Five in-depth case studies (Hongkong, Tokyo-Narita, London- Heathrow, Chicago- O'Hare and Paris-Charles de ...

  14. A comparison of aircraft trajectory-based and aggregate queue-based control of airport taxi processes

    E-Print Network [OSTI]

    Lee, Hanbong

    There is significant potential to decrease fuel burn, emissions, and delays of aircraft at airports by optimizing surface operations. A simple surface traffic optimization approach is to hold aircraft back at the gates ...

  15. Using a Constant Volume Displacement Ventilation System to Create a Micro Climate in a Large Airport Terminal in Bangkok 

    E-Print Network [OSTI]

    Simmonds, P.; Gaw, W.

    1996-01-01

    In order to conserve energy and create a comfortable climate for both passengers and workers at a new large international airport in Thailand, a design concept was created where only the first 2m above the occupied zone is conditioned...

  16. Estimating Traveler Populations at Airport and Cruise Terminals for Population Distribution and Dynamics

    SciTech Connect (OSTI)

    Jochem, Warren C; Sims, Kelly M; Bright, Eddie A; Urban, Marie L; Rose, Amy N; Coleman, Phil R; Bhaduri, Budhendra L

    2013-01-01

    In recent years, uses of high-resolution population distribution databases are increasing steadily for environmental, socioeconomic, public health, and disaster-related research and operations. With the development of daytime population distribution, temporal resolution of such databases has been improved. However, the lack of incorporation of transitional population, namely business and leisure travelers, leaves a significant population unaccounted for within the critical infrastructure networks, such as at transportation hubs. This paper presents two general methodologies for estimating passenger populations in airport and cruise port terminals at a high temporal resolution which can be incorporated into existing population distribution models. The methodologies are geographically scalable and are based on, and demonstrate how, two different transportation hubs with disparate temporal population dynamics can be modeled utilizing publicly available databases including novel data sources of flight activity from the Internet which are updated in near-real time. The airport population estimation model shows great potential for rapid implementation for a large collection of airports on a national scale, and the results suggest reasonable accuracy in the estimated passenger traffic. By incorporating population dynamics at high temporal resolutions into population distribution models, we hope to improve the estimates of populations exposed to or at risk to disasters, thereby improving emergency planning and response, and leading to more informed policy decisions.

  17. EA-2000: Proposed Land Transfer to Develop a General Aviation Airport at the East Tennessee Technology Park Heritage Center, Oak Ridge, Tennessee

    Broader source: Energy.gov [DOE]

    DOE is preparing an EA to assess potential environmental impacts of the proposed land transfer to the Metropolitan Knoxville Airport Authority for the development of a general aviation airport at the East Tennessee Technology Park Heritage Center, in Oak Ridge, Tennessee.

  18. DFW Airport 

    E-Print Network [OSTI]

    Dennis, J. R.

    2011-01-01

    ? Rents ~2 million cars per year ? Total electric ? 7.7 million kWh annually 10 Continuous Commissioning? - Consolidated Rent-A-Car Center CC? Assessment/Implementation ? Excessive outside air ? Duct static pressure too high ? Economizer cycle... at t H o u rs (K W H ) RAC Electric Consumption Over $767,000 in Total Savings 18% reduction in annual average kWh 11 Continuous Commissioning? - Consolidated Rent-A-Car Center Results of CC Project 12 Continuous Commissioning...

  19. Center for Energy Nanoscience at USC

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

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

  20. Bandgap Engineering of 1-Dimensional Nitride and Oxynitride Materials for Solar Water Splitting

    E-Print Network [OSTI]

    Hahn, Christopher

    2012-01-01

    Hydrogen Generation from Water Using Solar Energy.E. A. ; Lewis, N. S. Solar Water Splitting Cells. Chem RevWafer-Level Photocatalytic Water Splitting on Gan Nanowire

  1. Demonstration of a semipolar (10(1)over-bar(3)over-bar) InGaN/GaN green light emitting diode

    E-Print Network [OSTI]

    2005-01-01

    InGaN / GaN green light emitting diode R. Sharma, a? P. M.green ??525 nm? light emitting diode ?LED?. The fabricated

  2. Growth process for gallium nitride porous nanorods

    DOE Patents [OSTI]

    Wildeson, Isaac Harshman; Sands, Timothy David

    2015-03-24

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

  3. The Effect of the Thermal Boundary Resistance on Self-Heating of AlGaN/GaN HFETs

    E-Print Network [OSTI]

    sound velocity in GaN. The cut off wave vector is given by where NA is the Avogadro number, is the mass

  4. Scanned probe characterization of semiconductor nanostructures

    E-Print Network [OSTI]

    Law, James Jeremy MacDonald

    2009-01-01

    termination of these basal plane stacking faults is a partialtermination of threading edge dislocations. This signifies that dislocations in a–plane GaN may, unlike partial

  5. INSTITUTE OF PHYSICS PUBLISHING SEMICONDUCTOR SCIENCE AND TECHNOLOGY Semicond. Sci. Technol. 17 (2002) 476479 PII: S0268-1242(02)31655-9

    E-Print Network [OSTI]

    Pala, Nezih

    2002-01-01

    to the traps in GaN or AlGaN layers. At high channel concentrations, the electron spillover from the 2D

  6. Converge-Cast: On the Capacity and Delay Xinbing Wang1,2, Luoyi Fu1, Xiaohua Tian1, Yuanzhe Bei1, Qiuyu Peng1, Xiaoying Gan1, Hui Yu1, Jing Liu1

    E-Print Network [OSTI]

    Wang, Xinbing

    1 Converge-Cast: On the Capacity and Delay Tradeoffs Xinbing Wang1,2, Luoyi Fu1, Xiaohua Tian1 define an ad hoc network where multiple sources transmit packets to one destination as Converge-Cast) for both strategies. Index Terms--ConvergeCast, Capacity, Delay 1 INTRODUCTION Converge-cast network

  7. Analysis of leakage current mechanisms in Schottky contacts to GaN and Al0.25Ga0.75N/GaN grown by molecular-beam epitaxy

    E-Print Network [OSTI]

    Yu, Edward T.

    that the key carrier transport process is emission of electrons from a trap state near the metal independent of temperature, indicating that conduction is dominated by tunneling transport. At higher current in n-type Schottky contacts remains an outstanding challenge in the development of electronic

  8. High-density Er-implanted GaN optical memory devices Boon K. Lee, Robert Chih-Jen Chi, David Liang-Chiun Chao, Ji Cheng, Irving Yeong-Ning Chry,

    E-Print Network [OSTI]

    Cincinnati, University of

    . The integrated upconversion emission power was measured to be 40 pW when pumped by a 840-nm laser at 265 m, volumetric storage methods increase storage capacity by stacking data three dimension- ally. Based on optical larger than the existing optical disk technologies. First proposed in 1960, volumetric optical data

  9. Acetic Acid (H3COOH): GaAs; Pb; Ti Hydrochloric Acid (HCl): Al; Cr; Cu; Fe2O3; Ga; GaAs; GaN; In; Fe; Pb; Ni; NiO, Ni2O3; Sn;

    E-Print Network [OSTI]

    Garmestani, Hamid

    ferrocyanide (s) KMnO4 : potassium permanganate (s) FeCl3 : ferric chloride (s) NH4SO5 : ammonium persulfate (s

  10. Excitonic parameters of GaN studied by time-of-flight spectroscopy T. V. Shubina, A. A. Toropov, G. Pozina, J. P. Bergman, M. M. Glazov et al.

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    thermite reactions J. Appl. Phys. 106, 083306 (2009) Additional information on Appl. Phys. Lett. Journal

  11. Cubic GaN formation in MnGaN multilayer films grown on 6H-SiC,,0001... Y. Cui, V. K. Lazorov, M. M. Goetz, H. Liu, D. P. Robertson, M. Gajdardziska-Josifovska,

    E-Print Network [OSTI]

    Li, Lian

    improved film quality possibly due to the surfactant effect of Mn. Based on the one-dimensional Ising model attention due to their applications in blue lasers, light- emitting diodes, and high-temperature electronics-III concentration can be controlled precisely. How- ever, limits exist as to how much one can vary the alloy

  12. Letter Report: Yucca Mountain Environmental Monitoring Systems Initiative - Air Quality Scoping Study for Tonopah Airport, Nye County, Nevada

    SciTech Connect (OSTI)

    J. Engelbrecht; I. Kavouras; D Campbell; S. Campbell; S. Kohl, D. Shafer

    2008-08-01

    The Desert Research Institute (DRI) is performing a scoping study as part of the U.S. Department of Energy's Yucca Mountain Environmental Monitoring Systems Initiative (EMSI). The main objective is to obtain baseline air quality information for Yucca Mountain and an area surrounding the Nevada Test Site (NTS). Air quality and meteorological monitoring and sampling equipment housed in a mobile trailer (shelter) is collecting data at eight sites outside the NTS, including Ash Meadows National Wildlife Refuge (NWR), Tonopah Airport, Beatty, Rachel, Caliente, Pahranagat NWR, Crater Flat, and the Tonopah Airport, and at four sites on the NTS (Engelbrecht et al., 2007a-d). The trailer is stationed at any one site for approximately eight weeks at a time. This letter report provides a summary of air quality and meteorological data, on completion of the site's sampling program.

  13. Letter Report Yucca Mountain Environmental Monitoring Systems Initiative - Air Quality Scoping Study for Tonopah Airport, Nye County, Nevada

    SciTech Connect (OSTI)

    J. Engelbrecht; I. Kavouras; D. Campbell; S. Campbell; S. Kohl; D. Shafer

    2009-04-02

    The Desert Research Institute (DRI) is performing a scoping study as part of the U.S. Department of Energy's Yucca Mountain Environmental Monitoring Systems Initiative (EMSI). The main objective is to obtain baseline air quality information for Yucca Mountain and an area surrounding the Nevada Test Site (NTS). Air quality and meteorological monitoring and sampling equipment housed in a mobile trailer (shelter) is collecting data at eight sites outside the NTS, including Ash Meadows National Wildlife Refuge (NWR), Tonopah Airport, Beatty, Rachel, Caliente, Pahranagat NWR, Crater Flat, and the Tonopah Airport, and at four sites on the NTS (Engelbrecht et al., 2007a-d). The trailer is stationed at any one site for approximately eight weeks at a time. This letter report provides a summary of air quality and meteorological data, on completion of the site's sampling program.

  14. Electric Ground Support Equipment Advanced Battery Technology Demonstration Project at the Ontario Airport

    SciTech Connect (OSTI)

    Tyler Gray; Jeremy Diez; Jeffrey Wishart; James Francfort

    2013-07-01

    The intent of the electric Ground Support Equipment (eGSE) demonstration is to evaluate the day-to-day vehicle performance of electric baggage tractors using two advanced battery technologies to demonstrate possible replacements for the flooded lead-acid (FLA) batteries utilized throughout the industry. These advanced battery technologies have the potential to resolve barriers to the widespread adoption of eGSE deployment. Validation testing had not previously been performed within fleet operations to determine if the performance of current advanced batteries is sufficient to withstand the duty cycle of electric baggage tractors. This report summarizes the work performed and data accumulated during this demonstration in an effort to validate the capabilities of advanced battery technologies. This report summarizes the work performed and data accumulated during this demonstration in an effort to validate the capabilities of advanced battery technologies. The demonstration project also grew the relationship with Southwest Airlines (SWA), our demonstration partner at Ontario International Airport (ONT), located in Ontario, California. The results of this study have encouraged a proposal for a future demonstration project with SWA.

  15. Article Tools Printer-friendly

    E-Print Network [OSTI]

    Espinosa, Horacio D.

    Piezoelectricity in 3D"). Gallium nitride (GaN) is among the most technologically relevant semiconducting materials. "We thought these nanowires should show piezoelectricity in 3D, and aimed at obtaining all that individual GaN nanowires as small as 60 nanometers show piezoelectric behavior in 3D up to six times

  16. Myers et al. Page 1 Use of High Temperature Hydrogen Annealing to

    E-Print Network [OSTI]

    Myers, Tom

    , Department of Chemical Engineering West Virginia University, Morgantown, WV 26506 J. Alam, Electrical Eng growth of GaN and AlN as well as with thick, "free-standing" layers grown by hydride vapor phase epitaxy in this study were Ga-polar GaN layers grown on (0001) sapphire grown at TDI, Inc. using hydride vapor phase

  17. 438 OPTICS LETTERS / Vol. 26, No. 7 / April 1, 2001 Electric-field-induced second-harmonic generation

    E-Print Network [OSTI]

    -harmonic generation is used to detect electric fields in a GaN UV Schottky photodiode and in a GaN light. The photocurrent generated by this technique is found to be less than 100 pA when the fundamental and second can permit SH generation through a third-order process called electric-field-induced second

  18. Home | Login | Register Now [Jan 12,2012] Search Advanced Search

    E-Print Network [OSTI]

    Espinosa, Horacio D.

    Home | Login | Register Now [Jan 12,2012] Search Advanced Search News Products Technical Articles-Asia. Power/Alternative Energy GaN nanowires show more 3D piezoelectricity than bulk GaN Keywords: Ga, good for Asia A primer on wireless sensor network 'Shadow state' ups solar cell efficiency High

  19. Pyrolysis approach to the synthesis of gallium nitride nanorods Wei-Qiang Han and Alex Zettla)

    E-Print Network [OSTI]

    Zettl, Alex

    Pyrolysis approach to the synthesis of gallium nitride nanorods Wei-Qiang Han and Alex Zettla for publication 26 October 2001 Herein we describe a pyrolysis route to the synthesis of gallium nitride GaN nanorods. GaN nanorods have been grown by the pyrolysis of gallium dimethylamide and ferrocene under

  20. SiC rapid thermal carbonization of the (111)Si semiconductor-on-insulator structure and subsequent metalorganic chemical vapor deposition

    E-Print Network [OSTI]

    Cincinnati, University of

    vapor deposition with mixtures of propane and H2 at atmospheric pressure. Carbonization temperatures metalorganic chemical vapor deposition of GaN A. J. Steckla) and J. Devrajan University of Cincinnati . Metalorganic chemical vapor deposition growth of GaN on the 111 SiC SOI was carried out with trimethylgallium

  1. High efficiency single Ag nanowire/p-GaN substrate Schottky junction-based ultraviolet light emitting diodes

    E-Print Network [OSTI]

    Wu, Y.; Hasan, T.; Li, X.; Xu, P.; Wang, Y.; Shen, X.; Liu, X.; Yang, Q.

    2015-02-05

    for the removal of the native oxide layer on the GaN substrate to form the Schottky junction. First, the GaN substrate is ultrasonically degreased using acetone, ethanol, and deionized (DI) water for 5 min each. The substrate is then treated with a buffered...

  2. RESEARCH NEWS FEBRUARY 2007 | VOLUME 2 | NUMBER 1 9

    E-Print Network [OSTI]

    Rogers, John A.

    to epitaxial methods. In the process, nanoscale semiconductor components such as GaN, GaAs, or Si nanowires- area solar cells. D. Jason Palmer A three-layer stack of GaN high-electron mobility transistors, Si metal oxide semiconductor field-effect transistors, and SWNT thin-film transistors on a flexible

  3. Cr-Ga-N materials for negative electrodes in Li rechargeable batteries : structure, synthesis and electrochemical performance

    E-Print Network [OSTI]

    Kim, Miso

    2007-01-01

    Electrochemical performances of two ternary compounds (Cr2GaN and Cr3GaN) in the Cr-Ga-N system as possible future anode materials for lithium rechargeable batteries were studied. Motivation for this study was dealt in ...

  4. [15] H. Kind, J. M. Bonard, L. Forro, K. Kern, K. Hernadi, L. O. Nilsson, L. Schlaplach, Langmuir 2000, 16, 6877.

    E-Print Network [OSTI]

    Zettl, Alex

    scientists to develop a range of potential applications.[1] Meanwhile, one- and two-dimensional GaN and its, poor purity, and poor reproducibility. In the production of GaN±carbon composite nanotubes, the number furnace, under flowing methane and at 900 C for 15 min. The GaN nano- rods, previously light yellow

  5. All Stem Cell Publications by CIRM-CSULB Interns Anderson AJ, Haus DL, Hooshmand MJ, Perez H, Sontag CJ, Cummings BJ. 2011. Achieving

    E-Print Network [OSTI]

    Manley, Steven L.

    , Wang X, Xu F, Gu Y, Xu X, Tang J, Zhou H, Zhang X, Gan X, Van Ness G, Ma X, Fu X, Meng Z, Zhang W, Wang YD, Van Ness C, Yu D, Xu R, Van Ness C, Gan Y, Zhou H, Tang J, Lou G, Wang Y, Wu J, Yen Y, #12

  6. Nov. 5, 2003 1Soon Cho_AVS 50th International Symposium (Baltimore) RealReal--Time InTime In--Situ Chemical Sensing inSitu Chemical Sensing in

    E-Print Network [OSTI]

    Rubloff, Gary W.

    detection and classification ­ Semi-quantitative sensing for process understanding · In-situ chemical) ­ Multi-use: compatible with fault detection and process learning · Apply to GaN MOCVD for advanced Composer acoustic sensor GaN MOCVD PROCESS CHAMBER EMF MOCVD System Inficon Transpector mass spectrometer

  7. Opto Working Group Meeting March 21, 2014

    E-Print Network [OSTI]

    Gan, K. K.

    Summary of failures after burn-in/thermal cycles Summary K.K. Gan #12;K.K. Gan Opto Working Group Implemented several improvements based on experience gained from production of 1st generation opto cold solder is a major cause of opto-link failures opto-boards built by OSU have ~0.1% broken

  8. Ultra-thin ohmic contacts for p-type nitride light emitting devices

    SciTech Connect (OSTI)

    Raffetto, Mark; Bharathan, Jayesh; Haberern, Kevin; Bergmann, Michael; Emerson, David; Ibbetson, James; Li, Ting

    2014-06-24

    A flip-chip semiconductor based Light Emitting Device (LED) can include an n-type semiconductor substrate and an n-type GaN epi-layer on the substrate. A p-type GaN epi-layer can be on the n-type GaN epi-layer and a metal ohmic contact p-electrode can be on the p-type GaN epi-layer, where the metal ohmic contact p-electrode can have an average thickness less than about 25 .ANG.. A reflector can be on the metal ohmic contact p-electrode and a metal stack can be on the reflector. An n-electrode can be on the substrate opposite the n-type GaN epi-layer and a bonding pad can be on the n-electrode.

  9. Microsoft PowerPoint - To NETL Albany Site from Eugene, Oregon Airport Directions.ppt [Compatibility Mode]

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on darkMicroorganismsnowReport ARM28 MarchEugene, Oregon Airport 1.

  10. Microsoft PowerPoint - To NETL Albany Site from Portland, Oregon Airport (PDX) Directions.ppt [Compatibility Mode]

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on darkMicroorganismsnowReport ARM28 MarchEugene, Oregon Airport

  11. Tell President Obama About Coal River Mountain Coal River Mountain and the Heathrow Airport runway remind me how important it is to

    E-Print Network [OSTI]

    Hansen, James E.

    Tell President Obama About Coal River Mountain Coal River Mountain and the Heathrow Airport runway remind me how important it is to keep our eye on the ball. Coal River Mountain is the site of an absurdity. I learned about Coal River Mountain from students at Virginia Tech last fall. They were concerned

  12. Travel and Accommodations: Students will make their own travel arrangement and should plan flights to arrive on May 9th and leave on June 3rd.Students can take a taxi to the 92nd St. Y from the airport.The closest airport in LaGuardia.We will live and mee

    E-Print Network [OSTI]

    Bordenstein, Seth

    to arrive on May 9th and leave on June 3rd.Students can take a taxi to the 92nd St. Y from the airport for an optional fee. a contemporary art blitz - May 9th thru June 3rd, 2011 Course Description: This course week. Program Dates: May 9th ­ June 3rd 2011 Daily schedule to be announced. Contact: diane

  13. Public health assessment for St. Louis Airport, Hazelwood Interim Storage/Futura Coatings Company, St. Louis, St. Louis County, Missouri, Region 7. Cerclis No. MOD980633176. Preliminary report

    SciTech Connect (OSTI)

    Not Available

    1994-01-20

    The St. Louis Airport/Hazelwood Iterim Storage/Futura Coatings Company, a National Priorities List site, is in St. Louis County, Missouri. From 1946 to 1973, the site was used to store radioactive materials resulting from uranium processing. High levels of uranium, thorium, radium, and radon were detected in soil, groundwater, and air. The site is still being used to store radioactive materials. The Agency for Toxic Substances and Disease Registry considers the St. Louis Airport site to be an indeterminate public health hazard. Although there are emissions of radon and the presence of thorium in on-site air and off-site soils and the emission of radiation resulting from the presence of these materials is not currently considered a health hazard. At present conditions, the concentration of radon off-site is indistinguishable from background levels. However, in the past, these contaminants may have been present at levels of health concern.

  14. Geochemical information for sites contaminated with low-level radioactive wastes: II. St. Louis Airport Storage Site

    SciTech Connect (OSTI)

    Seeley, F.G.; Kelmers, A.D.

    1985-01-01

    The St. Louis Airport Storage Site (SLASS) became radioactively contaminated as a result of wastes that were being stored from operations to recover uranium from pitchblende ores in the 1940s and 1950s. The US Department of Energy is considering various remedial action options for the SLASS under the Formerly Utilized Site Remedial Action Program (FUSRAP). This report describes the results of geochemical investigations, carried out to support the FUSRAP activities and to aid in quantifying various remedial action options. Soil and groundwater samples from the site were characterized, and sorption ratios for uranium and radium and apparent concentration limit values for uranium were measured in soil/groundwater systems by batch contact methodology. The uranium and radium concentrations in soil samples were significantly above background near the old contaminated surface horizon (now at the 0.3/sup -/ to 0.9/sup -/m depth); the maximum values were 1566 ..mu..g/g and 101 pCi/g, respectively. Below about the 6/sup -/m depth, the concentrations appeared to be typical of those naturally present in soils of this area (3.8 +- 1.2 ..mu..g/g and 3.1 +- 0.6 pCi/g). Uranium sorption ratios showed stratigraphic trends but were generally moderate to high (100 to 1000 L/kg). The sorption isotherm suggested an apparent uranium concentration limit of about 200 mg/L. This relatively high solubility can probably be correlated with the carbonate content of the soil/groundwater systems. The lower sorption ratio values obtained from the sorption isotherm may have resulted from changes in the experimental procedure or the groundwater used. The SLASS appears to exhibit generally favorable behavior for the retardation of uranium solubilized from waste in the site. Parametric tests were conducted to estimate the sensitivity of uranium sorption and solubility to the pH and carbonate content of the system.

  15. Low-cost interference lithography

    E-Print Network [OSTI]

    Fucetola, Corey P.

    The authors report demonstration of a low-cost ( ? 1000 USD) interference lithography system based on a Lloyd’s mirror interferometer that is capable of ? 300?nm pitch patterning. The components include only a 405?nm GaN ...

  16. Discovery of Fungal Cell Wall Components Using Evolutionary and Functional Genomics

    E-Print Network [OSTI]

    Sain, Divya

    2013-01-01

    Reviews 23(1–2): 1-8. Duo-Chuan, L. (2006). "Review ofexpression in bacteria." Yi Chuan 33( 10): 1029-38. Figure 1Wiwat et al. 2004; Duo-Chuan 2006; Gan, Yang et al. 2007).

  17. Light extraction enhanced white light-emitting diodes with multi-layered phosphor configuration

    E-Print Network [OSTI]

    You, Jiun Pyng; Tran, Nguyen T.; Shi, Frank G.

    2010-01-01

    efficiency of GaN-Based power LEDs,” IEEE Photon. Technol.include GaN based blue power LED chips made by Bridgeluxthe more emission power of LEDs is lost as the phosphor

  18. Baccus, S.A., and Meister, M. (2002). Neuron 36, this issue, 909919. Benardete, E.A., and Kaplan, E. (1999). Vis. Neurosci. 16, 355368.

    E-Print Network [OSTI]

    Sur, Mriganka

    2002-01-01

    , photoreceptor layer; OPL, outer plexiform layer; INL, inner nuclear layer; IPL, inner plexiform layer; GCL, gan, hyperpolarizing might be Since the first reports of optical mapping of orientation advantageous for preserving

  19. PHYSIKALISCHES KOLLOQUIUM Wintersemester 2014/15

    E-Print Network [OSTI]

    Gerwert, Klaus

    prepared the semiconductor GaN which yielded with Indium-content (InxGa1-xN) bright blue light emitting diodes (LEDs) in the early 1990s, they triggered a fundamental transformation of lighting technology. Red

  20. Pedro Waloschek as Life-Savers

    E-Print Network [OSTI]

    ................................. 17 3 Richard Gans and Heinz Schmellenmeier's `Rheotron' ................... 31 4 Ernst Schiebold's `X-Ray-Guns'............................ 63 5 Rolf Wideroe's `Ray-Transformer'........................ 93 6 The End of the `X-Ray-Guns

  1. 2DEG electrodes for piezoelectric transduction of AlGaN/GaN MEMS resonators

    E-Print Network [OSTI]

    Weinstein, Dana

    A 2D electron gas (2DEG) interdigitated transducer (IDT) in Gallium Nitride (GaN) resonators is introduced and demonstrated. This metal-free transduction does not suffer from the loss mechanisms associated with more commonly ...

  2. High Voltage GaN-on-Si Field-Effect Transistors for Switching Applications

    E-Print Network [OSTI]

    Chen, Xu

    2015-01-01

    efficient GaN HEMT boost converter with 300-W output power29 Figure 3.13. Half-bridge boost converterin a half-bridge boost converter circuit shown in figure

  3. IEEE TRANSACTIONS ON POWER SYSTEMS, VOL. 15, NO. 2, MAY 2000 535 Stability-Constrained Optimal Power Flow

    E-Print Network [OSTI]

    IEEE TRANSACTIONS ON POWER SYSTEMS, VOL. 15, NO. 2, MAY 2000 535 Stability-Constrained Optimal Power Flow Deqiang Gan, Member, IEEE, Robert J. Thomas, Fellow, IEEE, and Ray D. Zimmerman, Member, IEEE

  4. Si-CMOS-Like Integration of AlGaN/GaN Dielectric-Gated High-Electron-Mobility Transistors 

    E-Print Network [OSTI]

    Johnson, Derek Wade

    2014-07-31

    production is projected to consume ~100,000 wafers per year by 2015 (Yole Development, “Power GaN – 2012 Edition”), this manufacturing breakthrough represents potential savings of ~$17 million per year....

  5. Center for Energy Nanoscience at USC

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

    LEDs. image Hz field profile for a photonic crystal micro-cavity. Large polarization and piezoelectric fields present in InGaN GaN material structures present in typical...

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

    Broader source: Energy.gov [DOE]

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

  7. Stimulated emission in GaN-based laser diodes far below the threshold region

    E-Print Network [OSTI]

    2014-01-01

    forward current of light-emitting diodes,” J. Appl. Phys.superluminescent light-emitting diodes based on GaN,” Appl.superluminescent light emitting diode structures,” J. Appl.

  8. IIl-nitride nanowires and heterostructures : growth and optical properties on nanoscale

    E-Print Network [OSTI]

    Zhou, Xiang, Ph. D. Massachusetts Institute of Technology

    2014-01-01

    Gallium nitride (GaN) and indium gallium nitride (InGaN) nanowires promise potential for further improving the electricity-to-light energy conversion efficiencies in light emitting diodes due to strain relaxation, reduced ...

  9. Wide band-gap nanowires for light emitting diodes

    E-Print Network [OSTI]

    Chesin, Jordan (Jordan Paul)

    2015-01-01

    Wide band-gap nanowires composed of GaN and ZnO are promising materials for unique designs and potential efficiency improvement of light emitting diodes (LEDs) for solid state lighting. The large surface-to-volume ratio ...

  10. EERE PowerPoint 97-2004 Template: Green Version

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

    tensors in fractured reservoirs using MEQ data. Proc. 49th US Symposium on Rock Mechanics and Geomechanics. San Francisco. June 29-July 1. 2. Gan, Q., Elsworth, D. (2015) A...

  11. HIGHLAND AVE OVERHILL ST

    E-Print Network [OSTI]

    Mohaghegh, Shahab

    COLORADOAVE W PARK AVE NORTH ST GANS AVE HOLLAND AVE NEWTON AVE SPRUCEST WILLEY ST 33H 23 25 59 39 34 4 4 27 Locations Emergency Phones N West Virginia University CAMPUS MAP #12;

  12. HIGHLAND AVE OVERHILL ST

    E-Print Network [OSTI]

    Mohaghegh, Shahab

    COLORADOAVE W PARK AVE NORTH ST GANS AVE HOLLAND AVE NEWTON AVE SPRUCEST WILLEY ST 33H 23 25 59 39 34 4 4 27 Locations Emergency Phones N West Virginia University CAMPUS MAP #12;P UNIVERSITY AVE UNIVERSITY AVE

  13. UNIVERSITY AVE UNIVERSITY AVE

    E-Print Network [OSTI]

    Mohaghegh, Shahab

    COLORADOAVE W PARK AVE NORTH ST GANS AVE HOLLAND AVE KOONTZ AVE RAWLEYLN TAKOMAST BALDWIN STKREPPS AVE WARREN Accessible Entrance Motorcycle Parking Locations Emergency Phones N MORGANTOWN Animal Sciences Farm Animal

  14. PNNL-SA-84872

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

    Research Society, Pittsburgh, PA. Matlack, K.S., H. Gan, M. Chaudhuri, W.K. Kot, W. Gong, T. Bardakci, I.L. Pegg, and I. Joseph. 2008. Melt Rate Enhancement for High Aluminum...

  15. Device-level thermal analysis of GaN-based electronics

    E-Print Network [OSTI]

    Bagnall, Kevin Robert

    2013-01-01

    Gallium nitride (GaN)-based microelectronics are one of the most exciting semiconductor technologies for high power density and high frequency electronics. The excellent electrical properties of GaN and its related alloys ...

  16. Characterization of Novel Semiconductor Alloys for Band Gap Engineering

    E-Print Network [OSTI]

    Broesler, Robert Joseph

    2010-01-01

    of Semiconductors: Physics and Materials Properties. 1999,in Properties of Advanced Semiconductor Materials GaN, AlN,Semiconductor Alloys: InAlN, ZnSeO and GaNAs 2 Materials Properties

  17. Negotiating with Bounded Rational Agents in Environments with Incomplete Information Using an

    E-Print Network [OSTI]

    Kraus, Sarit

    Department of Computer Science, Bar-Ilan University, Ramat-Gan, Israel 52900. bDepartment of Government and Politics issues over which mil- lions of lives are at stake, such as interstate disputes [25] and nuclear

  18. Introduction Research on eclogite-facies provinces during the last

    E-Print Network [OSTI]

    Andersen, Torgeir Bjørge

    al. 1991, Roberts 2003, Tucker et al. 2004, Hacker & Gans 2005). A number of publications have & Dewey 1998, Labrousse et al. 2002, Hacker et al. 2003, Brueckner & van Roermund 2004, Walsh & Hacker

  19. Crustal exhumation of the Western Gneiss Region UHP terrane, Ar thermochronology and fault-slip analysis

    E-Print Network [OSTI]

    Hacker, Bradley R.

    and fault-slip analysis Emily O. Walsh a,b, , Bradley R. Hacker a , Phillip B. Gans a , Martin S. Wong a the crust (Walsh and Hacker, 2004). Exhumation of continental crust from mantle depths has often been

  20. Development of a Residential Integrated Ventilation Controller

    E-Print Network [OSTI]

    Walker, Iain

    2013-01-01

    B. , and Gan, G. 1998 “Heat Recovery with Low Pressure LossSherman, M.H. 2003. “Heat Recovery in Building Envelopes. ”1998. “Field Survey of Heat Recovery Ventilation Systems. ”

  1. Adenovector GAD65 gene delivery into the rat trigeminal ganglion produces orofacial analgesia

    E-Print Network [OSTI]

    2009-01-01

    from the fact that direct injection into the ganglion makescolleagues [3] showed that direct injection of a GABA A Pagesite of action. Direct gan- glion injection of CGP46381, a

  2. Temporal Difference Based Actor Critic Learning -Convergence and Neural Implementation

    E-Print Network [OSTI]

    Meir, Ron

    Castro1 , Dmitry Volkinshtein1 and Ron Meir1 Department of Electrical Engineering1 and Biomedical recorded the activities of neurons while animals perform learning tasks [20], and used imag- ing techniques interpretation of the basal gan

  3. RealReal--Time AdvancedTime Advanced Process Control forProcess Control for

    E-Print Network [OSTI]

    Rubloff, Gary W.

    enables prediction of crystal quality Significance GaN HEMT technology requires precise control of Al to 35% AlN) High: breakdown suffers Low: 2DEG diminished Thickness (~20 to 25 nm) Thick: pinch

  4. IBL General Meeting 1 June 18, 2010

    E-Print Network [OSTI]

    Gan, K. K.

    Recovery Time vs Dosage K.K. Gan Fit power vs time during annealing to exponential function recovery instead of FR4 for heat removal need to understand the current VCSEL problem to see to see

  5. Friday, March 12, 2010 "The Age of Stupid"

    E-Print Network [OSTI]

    Nightingale, Peter

    ENVIRONMENTALISTS! Revision history (Rochester/South Florida/Westerly, Rhode Island) #12;Drilling Off- heat lost had need had get E his no more his more belch, ba- Bush, A, Rea- shore in ma who we gan to y Drill- B 7 5 bon rack le S Ron- ing more oil, D o we his no more his in ma who we gan to heat lost had

  6. A 3-10 GHZLCR-matched Power Amplifier using Flip-Chip Mounted AlGaN/GaN HEMTs

    E-Print Network [OSTI]

    York, Robert A.

    amplifier using GaN- HEMTs-on-Sapphire. I INTRODUCTION GaN HEMTs have enormous potential for realizing high-power Traveling Wave Power Amplifier circuit (TWPA)[1][2] for realization of wideband power amplifiersWE4A-5 A 3-10 GHZLCR-matched Power Amplifier using Flip-Chip Mounted AlGaN/GaN HEMTs Jane J

  7. 2012/12/27 2 2012/12/27 3

    E-Print Network [OSTI]

    Hung, Shih-Hao

    HBTSolar cell Thick film MOCVD MMIC Lasers (strained QW, dilute nitride, QD) Solar cell III-V on Si Sb-based III-V Rectifier HBT, HEMT, Solar cells III-V on Si III-V on Si Solar cellSolar cell GaN LED, LD, power, lighting (AlGaInP, GaN) Communication (LD and detectors) Photovoltaic: Solar cells Design-house Epi

  8. Journal of Light Emitting Diodes Vol 2 N0 1, April 2010 1 Abstract--In metal organic vapor phase epitaxy we developed

    E-Print Network [OSTI]

    Wetzel, Christian M.

    Journal of Light Emitting Diodes Vol 2 N0 1, April 2010 1 Abstract-- In metal organic vapor phase epitaxy we developed GaInN/GaN quantum well material suitable for 500 ­ 580 nm light emitting diodes at longer wavelengths. Index Terms-- a-plane GaN, GaInN, Green light emitting diode, m-plane GaN I

  9. Abbreviated epitaxial growth mode (AGM) method for reducing cost and improving quality of LEDs and lasers

    DOE Patents [OSTI]

    Tansu, Nelson; Chan, Helen M; Vinci, Richard P; Ee, Yik-Khoon; Biser, Jeffrey

    2013-09-24

    The use of an abbreviated GaN growth mode on nano-patterned AGOG sapphire substrates, which utilizes a process of using 15 nm low temperature GaN buffer and bypassing etch-back and recovery processes during epitaxy, enables the growth of high-quality GaN template on nano-patterned AGOG sapphire. The GaN template grown on nano-patterned AGOG sapphire by employing abbreviated growth mode has two orders of magnitude lower threading dislocation density than that of conventional GaN template grown on planar sapphire. The use of abbreviated growth mode also leads to significant reduction in cost of the epitaxy. The growths and characteristics of InGaN quantum wells (QWs) light emitting diodes (LEDs) on both templates were compared. The InGaN QWs LEDs grown on the nano-patterned AGOG sapphire demonstrated at least a 24% enhancement of output power enhancement over that of LEDs grown on conventional GaN templates.

  10. BATON ROUGE METRO AIRPORT

    E-Print Network [OSTI]

    Harms, Kyle E.

    STATE ID AND SURRENDER CERTIFICATE TO CASHIER ALONG WITH PARKING TICKET WHEN EXITING FROM LOT. PARKING WITH PARKING TICKET WHEN EXITING FROM LOT. PARKING SERVICES PROVIDED BY STANDARD PARKING, INC. 225-355-2978 Use STATE ID AND SURRENDER CERTIFICATE TO CASHIER ALONG WITH PARKING TICKET WHEN EXITING FROM LOT. PARKING

  11. Easterwood Airport - 15 

    E-Print Network [OSTI]

    Unknown

    2009-01-01

    175 200 225 250 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2 Mean (mm) De p t h ( c m) Fig. 16. Mean grain size graph for core 4B 26 Fig. 17. Stratigraphic transect profile #1. % Sand Mean Size 27 In transect #1 in the north... 125 150 175 200 225 250 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 Mean (mm) Dep t h (cm) 25 26 Core: TXD-1D Particle Size Distribution 0.1 1 10 100 1000 Particle...

  12. La Guardia Airport Background

    E-Print Network [OSTI]

    , which was grandfathered in -- so most transcontinental and international flights use the area's other

  13. A. Kusiak, C.A. Caldarone, M.D. Kelleher, F.S. Lamb, T.J. Persoon, Y. Gan, and A. Burns, Mining Temporal Data Sets: Hypoplastic Left Heart Syndrome Case Study, in B.V. Dasarathy (Ed.), Proceedings of the SPIE Conference on Data

    E-Print Network [OSTI]

    Kusiak, Andrew

    of Cardiothorcic Surgery and ***Pediatrics University of Iowa Hospital and Clinics The University of Iowa Iowa City. An experienced team of physicians, nurses, and therapists is required to successfully manage the infant. However for the simultaneous collection of 73 physiologic, laboratory, and nurse-assessed variables. Data records were created

  14. Annual Review of BPA-Funded Projects in Natural and Artificial Propagation of Salmonids, March 27-29, 1985, Holiday Inn Airport, Portland, Oregon.

    SciTech Connect (OSTI)

    United States. Bonneville Power Administration.

    1985-04-01

    The Fish and Wildlife Division of Bonneville Power Administration (BPA) hosted a meeting for contractors to present the results of fiscal year 1984 research conducted to implement the Northwest Power Planning Council's Fish and Wildlife Program. The meeting focused on those projects specifically related to natural and artificial propagation of salmonids. The presentations were held at the Holiday Inn Airport in Portland, Oregon, on March 27-29, 1985. This document contains abstracts of the presentations from that meeting. Section 1 contains abstracts on artificial propagation, fish health, and downstream migration, and Section 2 contains abstracts on natural propagation and habitat improvement. The abstracts are indexed by BPA Project Number and by Fish and Wildlife Program Measure. The registered attendees at the meeting are listed alphabetically in Appendix A and by affiliation in Appendix B.

  15. Structural and optical properties of InGaN–GaN nanowire heterostructures grown by molecular beam epitaxy

    SciTech Connect (OSTI)

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

    2011-01-01

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

  16. Electrical properties of atomic layer deposited aluminum oxide on gallium nitride

    SciTech Connect (OSTI)

    Esposto, Michele; Krishnamoorthy, Sriram; Nath, Digbijoy N.; Bajaj, Sanyam; Hung, Ting-Hsiang; Rajan, Siddharth

    2011-09-26

    We report on our investigation of the electrical properties of metal/Al{sub 2}O{sub 3}/GaN metal-insulator-semiconductor capacitors. We determined the conduction band offset and interface charge density of the alumina/GaN interface by analyzing the capacitance-voltage characteristics of atomic layer deposited Al{sub 2}O{sub 3} films on GaN substrates. The conduction band offset at the Al{sub 2}O{sub 3}/GaN interface was calculated to be 2.13 eV, in agreement with theoretical predications. A non-zero field of 0.93 MV/cm in the oxide under flat-band conditions in the GaN was inferred, which we attribute to a fixed net positive charge density of magnitude 4.60 x 10{sup 12 }cm{sup -2} at the Al{sub 2}O{sub 3}/GaN interface. We provide hypotheses to explain the origin of this charge by analyzing the energy band line-up.

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

    SciTech Connect (OSTI)

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

    1988-06-01

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

  18. Self-annihilation of inversion domains by high energy defects in III-Nitrides

    SciTech Connect (OSTI)

    Koukoula, T.; Kioseoglou, J. Kehagias, Th.; Komninou, Ph.; Ajagunna, A. O.; Georgakilas, A.

    2014-04-07

    Low-defect density InN films were grown on Si(111) by molecular beam epitaxy over an ?1??m thick GaN/AlN buffer/nucleation layer. Electron microscopy observations revealed the presence of inverse polarity domains propagating across the GaN layer and terminating at the sharp GaN/InN (0001{sup ¯}) interface, whereas no inversion domains were detected in InN. The systematic annihilation of GaN inversion domains at the GaN/InN interface is explained in terms of indium incorporation on the Ga-terminated inversion domains forming a metal bonded In-Ga bilayer, a structural instability known as the basal inversion domain boundary, during the initial stages of InN growth on GaN.

  19. Airports of the Future: The Development of Airport Systems

    E-Print Network [OSTI]

    and scope. This is the model for most successful manufacturers and service providers, such as Walmart

  20. Airport sustainability encompasses a wide variety of airport management and

    E-Print Network [OSTI]

    Minnesota, University of

    is to consider renewable energies. Solar photovoltaic (PV), which uses panels to absorb solar energy, is prob- ably the most commonly implemented type of renewable energy. Solar PV panels can be ground a cold winter climate, the efficiency of solar PV is high in Minnesota because of its many sunny days

  1. Hong Kong InternationalHong Kong International AirportAirport

    E-Print Network [OSTI]

    Prevedouros, Panos D.

    recyclingrecycling Mechanized food waste compostersMechanized food waste compostersMechanized food waste compostersMechanized food waste composters which reduce waste volume by up towhich reduce waste volume by up to 90

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

    E-Print Network [OSTI]

    Ravikirthi, Pradhyumna

    2014-08-10

    -sputtered contact. 20 3. AU-FREE SCHEME FOR GALLIUM NITRIDE 3.1. Survey of Au-free contacts in literature and scope for improvement For n-type GaN, it was observed that aluminium and gold form poor ohmic contacts (resistances in the order of 10-3 ?/cm2...] used Ti/Al and found better results for ohmic resistance compared to GaN[17]. However, Ti/Al contacts lost its stability at high temperatures due to formation of aluminium lumps on the surface, increasing its roughness and resistance. Fan et al [20...

  3. Screening of the quantum-confined Stark effect in AlN/GaN nanowire superlattices by germanium doping

    SciTech Connect (OSTI)

    Hille, P. Müßener, J.; Becker, P.; Teubert, J.; Schörmann, J.; Eickhoff, M.; Mata, M. de la; Rosemann, N.; Chatterjee, S.; Magén, C.; Arbiol, J.; Institucio Catalana de Recerca i Estudis Avançats , 08010 Barcelona, CAT

    2014-03-10

    We report on electrostatic screening of polarization-induced internal electric fields in AlN/GaN nanowire heterostructures with germanium-doped GaN nanodiscs embedded between AlN barriers. The incorporation of germanium at concentrations above 10{sup 20}?cm{sup –3} shifts the photoluminescence emission energy of GaN nanodiscs to higher energies accompanied by a decrease of the photoluminescence decay time. At the same time, the thickness-dependent shift in emission energy is significantly reduced. In spite of the high donor concentration, a degradation of the photoluminescence properties is not observed.

  4. Printed assemblies of ultrathin, microscale inorganic light emitting diodes for deformable and semitransparent displays

    DOE Patents [OSTI]

    Rogers, John A; Nuzzo, Ralph; Kim, Hoon-sik; Brueckner, Eric; Park, Sang Il; Kim, Rak Hwan

    2014-10-21

    Described herein are printable structures and methods for making, assembling and arranging electronic devices. A number of the methods described herein are useful for assembling electronic devices where one or more device components are embedded in a polymer which is patterned during the embedding process with trenches for electrical interconnects between device components. Some methods described herein are useful for assembling electronic devices by printing methods, such as by dry transfer contact printing methods. Also described herein are GaN light emitting diodes and methods for making and arranging GaN light emitting diodes, for example for display or lighting systems.

  5. Intermixing and chemical structure at the interface between n-GaN and V-based contacts

    SciTech Connect (OSTI)

    Pookpanratana, S.; France, R.; Bar, M.; Weinhardt, L.; Fuchs, O.; Blum, M.; Yang, W.; Denlinger, J. D.; Moustakas, T. D.; Heske, C.

    2008-06-30

    The interface between n-type GaN and V-based contacts was characterized by soft x-ray spectroscopy. We have investigated the chemical interface structure before and after a rapid thermal annealing (RTA) step, which is crucial for the formation of an Ohmic contact. X-ray photoelectron and x-ray excited Auger electron spectra suggestthat RTA induces an accumulation of metallic Ga at the surface. Using x-ray emission spectroscopy, we find that the probed nitrogen atoms are in a VN-like environment, indicating that vanadium interacts with nitrogen atoms from the GaN to form VN.

  6. Electron mobility enhancement in AlN/GaN/AlN heterostructures with InGaN nanogrooves

    E-Print Network [OSTI]

    it was discovered by Davydov et al.1 and con- firmed by independent studies2,3 that its band gap is small, EG InN =0 The conduction band offset at GaN/AlN interface was estimated as EQW=0.7 EG AlN -EG GaN =1918 meV. The nanoN/GaN/AlN QW. The depth of the nanogroove is calculated as E0=0.8 EG GaN -EG InxGa1-xN . The band gap of InxGa1

  7. Vascular flora and vegetation of granite outcrops in the Central Mineral Region of Texas 

    E-Print Network [OSTI]

    Walters, Terrence Wesley

    1980-01-01

    Me nard ~ Llano F edencasb rg ~ LGJL 1L McCULLOCH i SAN SABA ( W LAMPASASy J gan Saba 8rady ~ r- ?. ? ? ? ? -Q Lamoasas ~ MENARD BURNETT L /+MASON LLANO I / Cc' Mason ~ Burner / / / ~ Jnncnon . BLANCO / / Johnson Crry LESPIE... Maga d ~ I KIMBLE p L r rc McCULLQCi. l MASAN SABA l LAMPASASX &7& gan Saba grasp ~ C c kampasas ) BURNETT . ) I LLANO r ~ Masoa glar a ~ ~ 1 ~ garnet ~ EB ATQ / ~ 84 /' ~ ieh ~ /U4cllaa BLANCO f /c J / 1 ede cksba 8 ~ dahhsaa 8...

  8. A publication of the Airport Technical Assistance Program of the Center for Transportation Studies at the University of Minnesota Winter 2014 Vol. 14, No. 1 For more on the Fall Forum, including video highlights, see www.AirTAP.umn.edu.

    E-Print Network [OSTI]

    Amin, S. Massoud

    at the University of Minnesota Winter 2014 Vol. 14, No. 1 Briefings For more on the Fall Forum, including video department. That full-time staff is augmented with 28 heavy equipment operators in the winter who work got a look at how the airport handles the snow and ice that's part of a typical Minnesota winter

  9. built by airport authority for

    E-Print Network [OSTI]

    Ladkin, Peter B.

    on landing 3.1.1.3.1.1.3 low weight on each main gear wheel 3.1.1.3.1.1.1.3 condition of RWY surface 3 between consequences of design and behaviour expected by pilots 3.1.1.3.2.2 braking systems' logical design 3.1.1.3.2 speed brakes and thrust reverser deployment delayed 3.1.1.3 braking delayed 3

  10. Issues associated with the metalorganic chemical vapor deposition of ScGaN and YGaN alloys.

    SciTech Connect (OSTI)

    Koleske, Daniel David; Knapp, James Arthur; Lee, Stephen Roger; Crawford, Mary Hagerott; Creighton, James Randall; Cross, Karen Charlene; Thaler, Gerald

    2009-07-01

    The most energy efficient solid state white light source will likely be a combination of individually efficient red, green, and blue LED. For any multi-color approach to be successful the efficiency of deep green LEDs must be significantly improved. While traditional approaches to improve InGaN materials have yielded incremental success, we proposed a novel approach using group IIIA and IIIB nitride semiconductors to produce efficient green and high wavelength LEDs. To obtain longer wavelength LEDs in the nitrides, we attempted to combine scandium (Sc) and yttrium (Y) with gallium (Ga) to produce ScGaN and YGaN for the quantum well (QW) active regions. Based on linear extrapolation of the proposed bandgaps of ScN (2.15 eV), YN (0.8 eV) and GaN (3.4 eV), we expected that LEDs could be fabricated from the UV (410 nm) to the IR (1600 nm), and therefore cover all visible wavelengths. The growth of these novel alloys potentially provided several advantages over the more traditional InGaN QW regions including: higher growth temperatures more compatible with GaN growth, closer lattice matching to GaN, and reduced phase separation than is commonly observed in InGaN growth. One drawback to using ScGaN and YGaN films as the active regions in LEDs is that little research has been conducted on their growth, specifically, are there metalorganic precursors that are suitable for growth, are the bandgaps direct or indirect, can the materials be grown directly on GaN with a minimal defect formation, as well as other issues related to growth. The major impediment to the growth of ScGaN and YGaN alloys was the low volatility of metalorganic precursors. Despite this impediment some progress was made in incorporation of Sc and Y into GaN which is detailed in this report. Primarily, we were able to incorporate up to 5 x 10{sup 18} cm{sup -3} Y atoms into a GaN film, which are far below the alloy concentrations needed to evaluate the YGaN optical properties. After a no-cost extension was granted on this program, an additional more 'liquid-like' Sc precursor was evaluated and the nitridation of Sc metals on GaN were investigated. Using the Sc precursor, dopant level quantities of Sc were incorporated into GaN, thereby concluding the growth of ScGaN and YGaN films. Our remaining time during the no-cost extension was focused on pulsed laser deposition of Sc metal films on GaN, followed by nitridation in the MOCVD reactor to form ScN. Finally, GaN films were deposited on the ScN thin films in order to study possible GaN dislocation reduction.

  11. Influence of external electric field on piezotronic effect in ZnO nanowires

    E-Print Network [OSTI]

    Wang, Zhong L.

    Wurtzite and zinc blende structured materials, such as ZnO, ZnS, GaN, CdS, and CdSe, have significant], piezopotential gated transistors [5, 6], LEDs [7], solar cells [8], photodetectors [9], and temperature sensors

  12. Effect of passivation on stress relaxation in electroplated copper films

    E-Print Network [OSTI]

    Huang, Rui

    Effect of passivation on stress relaxation in electroplated copper films Dongwen Gan and Paul S. Ho of interfacial mass transport by measuring stress relaxation in electroplated Cu films with four different cap examined.3,4 In particular, Hu et al.3 demonstrated a significant improvement in the EM lifetime by coating

  13. Isothermal stress relaxation in electroplated Cu films. I. Mass transport measurements

    E-Print Network [OSTI]

    Huang, Rui

    Isothermal stress relaxation in electroplated Cu films. I. Mass transport measurements Dongwen Gan-boundary mass transport measured from isothermal stress relaxation in electroplated Cu thin films. Thermal stresses in electroplated Cu films with and without passivation, subjected to thermal cycling

  14. 1066 IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, VOL. 15, NO. 4, JULY/AUGUST 2009 Metalorganic Vapor Phase Epitaxy of III-Nitride

    E-Print Network [OSTI]

    Gilchrist, James F.

    substrate exhibited a 24% improvement in output power as compared to LEDs on GaN templates grown using the conventional method. The increase in output power of the LEDs is attributed to improved internal quantum-emitting diode (LED) de- vices grown on patterned sapphire and planar substrates were compared. The nanopatterned

  15. Lattice site location of impurities in group III nitrides using emission channeling

    E-Print Network [OSTI]

    De Vries, Bart; Wahl, Ulrich

    The group III nitrides comprise the semiconducting materials InN, GaN, AlN and their ternary alloys. During the last decade, GaN has attracted widespread attention due to its large band gap and hardness. These properties, combined with the fact that its band gap can be adjusted by alloying it with InN and AlN, make GaN a suitable material for the fabrication of optical components that operate in the blue to ultraviolet region of the electromagnetic spectrum, and for microwave and high-power applications. Indeed, during the last couple of years, GaN-based blue and violet light-emitting devices (LEDs) and laser diodes have been realized and commercialized: the violet laser diodes will even be the keystone to the next generation of optical data storage standards, Blu-ray and HD-DVD. \\\\ \\\\ A key aspect in device production is the incorporation of dopants that can alter the electronic, magnetic or optical properties of the host material. For example, Si is often used to generate n-type GaN, while Mg is the most fr...

  16. Improving hole injection efficiency by manipulating the hole transport mechanism through

    E-Print Network [OSTI]

    Demir, Hilmi Volkan

    -emitting diodes (LEDs) for elec- tron overflow suppression. However, a typical EBL also reduces the hole injection to be the key to enhancing the hole injection efficiency. InGaN/ GaN LEDs with the proposed p-type AlGaN/GaN/AlGaN EBL have demonstrated substantially higher optical output power and external quantum efficiency

  17. Orogenic movement mechanism for the formation of symmetrical relief features in copper nitride thin films

    E-Print Network [OSTI]

    Zexian, Cao

    Orogenic movement mechanism for the formation of symmetrical relief features in copper nitride thin heterogeneity, etc. In preparing thin films of the thermally unstable copper nitride Cu3N, growth proceeds-gap semiconduc- tors such as SiC and GaN that are expected to operate at temperatures over 300 °C demand both

  18. Introduction The first organ-like instrument was

    E-Print Network [OSTI]

    Zhigilei, Leonid V.

    .g., electrification of the mechanical parts), new materials, and the demand for colossal orchestral or- gans's Eastman School of Music and will be inaugurated in Christ Church, Rochester, in 2008. The demand to- gether on the reconstruction of historical copper alloys--namely, brass--which dif- fer

  19. SCIENCE CHINA Technological Sciences

    E-Print Network [OSTI]

    Wang, Zhong L.

    University, Lanzhou 730000, China; 3 School of Material Science and Engineering, Georgia Institute on the piezoelectric semiconductor materials, such as ZnO, ZnS, CdS and GaN. With the usage of these piezoelectric.37 eV and large free-exciton binding energy of 60 meV at room temperature. Furthermore, splendid one

  20. Retinal Anatomy and Physiology Vision begins at the retina, where light is converted into

    E-Print Network [OSTI]

    Duong, Timothy Q.

    plexiform layer (IPL), and the gan- glion cell layer (GCL). The signals are transmitted to the fiber nerve is mainly localized in the GCL, but projects capillaries into the INL, IPL, and OPL.1,4,5 The choroidal the retinal pigment epithelium.1,4,5 The thickness of the choroid is reported to be 25­45 m in rats.6

  1. CHEN ET AL. VOL. XXX ' NO. XX ' 000000 ' XXXX www.acsnano.org

    E-Print Network [OSTI]

    Wang, Zhong L.

    lumens, higher efficiency, and lower power consumption than traditional lighting mod- ules density around 12.5 mW/m2 . The images of lighted GaN NWs LEDs and corresponding electroluminescence (EL an output power density of nearly 12.5 mW/m2 . Luminous LED modules based on n-GaN nanowires/p-GaN substrate

  2. 3190 IEEE TRANSACTIONS ON ELECTRON DEVICES, VOL. 60, NO. 10, OCTOBER 2013 Methodology for the Study of Dynamic

    E-Print Network [OSTI]

    del Alamo, Jesús A.

    event is characterized by a fast release of trapped charge through a temperature-independent tunneling-resistance, FET, GaN, high electron-mobility transistor (HEMT), transient, trapping. I. INTRODUCTION IN THE last3190 IEEE TRANSACTIONS ON ELECTRON DEVICES, VOL. 60, NO. 10, OCTOBER 2013 Methodology for the Study

  3. 333978-1-4577-1597-6/12/$26.00 2012 IEEE Proceedings of the 2012 24th International Symposium on Power Semiconductor Devices and ICs

    E-Print Network [OSTI]

    del Alamo, Jesús A.

    to the GaN channel. These traps release their electrons through a tunneling process and are most likely span of 11 decades. In OFF to ON time transients, we observe a fast release of trapped electrons through a temperature-independent tunneling process. We attribute this to border traps at the Al

  4. 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim p s scurrent topics in solid state physics

    E-Print Network [OSTI]

    Anderson, Timothy J.

    , Young Seok Kim, Olga Kryliouk* , and Tim Anderson Department of Chemical Engineering, University successfully reported; GaN NR growth by typical hydride vapor phase epitaxy (HVPE) [15], InN NR growth by hydride metal organic vapor phase epitaxy (H-MOVPE) from our efforts [9, 16], and AlN NR growth

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

    E-Print Network [OSTI]

    Lipson, Michal

    of obtaining a powder form of RE doped GaN involve a combustion reaction15 or an ammonolysis of freeze onto the Si substrate, obtained using a HeCd laser 325 nm . A pulsed N2 laser 337.1 nm with 4 ns pulse

  6. 46 SCIENTIFIC AMERICAN MARCH 2005 AGRICULTURAL TERRACES have been constructed

    E-Print Network [OSTI]

    ancestors' farming practices kicked off global warming thousands of years before we started burning coal as well. With the advent of coal- burning factories and power plants, industrial societies be- gan, current temperatures in northern parts of North America and Europe would be cool- er by three to four

  7. Dense colloidal fluids form denser amorphous sediments

    E-Print Network [OSTI]

    Schofield, Andrew B.

    for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 52900, Israel; and c School of Physics, by simple analytical centrifugation experiments, the density of colloidal fluids with the nature sedimentation in a centrifuge is sufficiently rapid to avoid crystalli- zation, demonstrate that the density

  8. A Study of the Nidana: An Underrated Canonical Text of the Mulasarvastivada-vinaya

    E-Print Network [OSTI]

    Kishino, Ryoji

    2013-01-01

    iti / sa t¯abhih. saha anek¯ani vars. a ¯ n.i ratim anubh¯an.i s.as.t.ivars.a´sat¯ani ca / a ¯ d¯?ptam a ¯ yasam .yatr¯adhik¯ara-janit¯ani var¯a n ? gan¯an¯am . rejur mukh¯

  9. Journal of Crystal Growth 298 (2007) 272275 Dislocation analysis in homoepitaxial GaInN/GaN light emitting

    E-Print Network [OSTI]

    Wetzel, Christian M.

    2007-01-01

    of GaInN/GaN-based light emitting diodes (LED) on quasi-bulk GaN with an atomically flat polished were much improved. The optical output power of the light emitting diode increased by more than one. Cathodoluminescence; A1. Threading dislocation density; A2. Homoepitaxial growth; B1. GaInN; B3. Light emitting diode

  10. High efficiency light emitting diode with anisotropically etched GaN-sapphire interface

    E-Print Network [OSTI]

    High efficiency light emitting diode with anisotropically etched GaN- sapphire interface M. H. Lo and optimization of a light-emitting diode projection micro-stereolithography three-dimensional manufacturingGaN micro-light emitting diodes Appl. Phys. Lett. 101, 231110 (2012) A bright cadmium-free, hybrid organic

  11. Friday-December 14, 2012 12:00 to 1:00 p.m.

    E-Print Network [OSTI]

    Devoret, Michel H.

    solar cells, high-speed and high-power transistors, and light-emitting diodes. In this talk, a different, the MOCVD growth of GaN is extended by the use of selective area growth, where the area of crystal growthHz opto-electromechanical resonator made out of high-stress SiN by modulating its spring constant at twice

  12. You are here: Home / News / 3D view of 1D nanostructures More services

    E-Print Network [OSTI]

    Espinosa, Horacio D.

    create tool to put the lid on solar power fluctuations Variability law for solar panels News 3D view of 1You are here: Home / News / 3D view of 1D nanostructures Share More services Related Links of nanogenerators based on GaN nanowires, for powering of self-powered nanodevices. This story is reprinted from

  13. Measurements of B?Ds(+)X decays

    E-Print Network [OSTI]

    Baringer, Philip S.

    1996-05-01

    at Albany, Albany, New York 12222 G. Crawford, R. Fulton, D. Fujino, K. K. Gan, K. Honscheid, H. Kagan, R. Kass, J. Lee, M. Sung, C. White, A. Wolf, and M. M. Zoeller Ohio State University, Columbus, Ohio 43210530556-2821/96/53~9!/4734~13!/$10.00 4734 © 1996...

  14. The relaxation of sheared magnetic fields --a contracting process Haisheng Ji1,2

    E-Print Network [OSTI]

    , and Haimin Wang2 1. Purple Mountain Observatory, 2 Beijing Xi Lu, Nanjing, 210008, China, jihs@pmo.ac.cn 2. Big Bear Solar Observatory, New Jersey Institute of Technology, 40386 North Shore Lane, Big Bear City by Ji et al. (2006) at GanYu Solar Station of Purple Mountain Observatory may provide a clue leading

  15. Published in IET Control Theory and Applications Received on 17th September 2010

    E-Print Network [OSTI]

    Qu, Zhihua

    photovoltaic generators in distribution networks H. Xin1 Z. Lu1 Z. Qu2 D. Gan1 D. Qi1 1 College of Electrical control strategy was provided to regulate the active and reactive power outputs of multiple photovoltaic amount of photovoltaics (PVs) integrated into the modern distribution networks due to their clean

  16. PHYSICAL REVIEW B 86, 075468 (2012) Atomic-resolution imaging of the polar (0001) surface of LiNbO3

    E-Print Network [OSTI]

    Kühnle, Angelika

    2012-01-01

    versatile materials for optical and acoustic applications due to its unusual piezoelectric, pyroelectric polarization may lead to very interesting applications, e.g., chemical sensing based on adsorption for the epitaxial growth of GaN.8 In contrast to traditional applications of LN, which mainly rely on its bulk

  17. Piezotronic Effect on ZnO Nanowire Film Based Temperature Sensor Limin Zhang,,

    E-Print Network [OSTI]

    Wang, Zhong L.

    potential in novel applications by conjunction of piezoelectric effect and semiconductor proper- ties.1-structured piezoelectric semiconductors, such as ZnO, GaN, and InN, have been of particular interest owing to their unique a piezoelectric potential across the crystal under strain. Piezoelectric-polarization- induced piezopotential

  18. Influence of pressure on photoluminescence and electroluminescence in GaN/InGaN/AlGaN quantum wells

    E-Print Network [OSTI]

    Weinstein, Benard.A.

    recently that the temperature shifts of the photo- and electroluminescence EL peak energies in Nichia greenV/GPa for the green and blue diodes, respectively. The observed pressure coefficients are much lower than those characteristic of the energy gap in GaN ( 40 meV/GPa) or the energy gap in InN ( 33 meV/GPa). This kind

  19. HYDROGEN LOCAL VIBRATIONAL MODES IN COMPOUND SEMICONDUCTORS

    E-Print Network [OSTI]

    McCluskey, Matthew

    HYDROGEN LOCAL VIBRATIONAL MODES IN COMPOUND SEMICONDUCTORS M.D. MCCLUSKEY* University) spectroscopy of hydrogen and deuterium in GaP, AlSb, ZnSe, and GaN has provided important information about the structures of dopant- hydrogen complexes and their interaction with the host lattice. In GaN:Mg, for example

  20. FAST COMPRESSIVE SAMPLING WITH STRUCTURALLY RANDOM MATRICES Thong T. Do

    E-Print Network [OSTI]

    FAST COMPRESSIVE SAMPLING WITH STRUCTURALLY RANDOM MATRICES Thong T. Do , Trac D. Tran and Lu Gan of fast and efficient com- pressive sampling based on the new concept of structurally random matrices low complexity and fast computation based on block processing and linear filtering. (iv

  1. Comparative study of field-dependent carrier dynamics and emission kinetics of InGaN/GaN light-emitting diodes grown on (11 2 2) semipolar versus (0001) polar

    E-Print Network [OSTI]

    Demir, Hilmi Volkan

    Articles you may be interested in Ultraviolet light-emitting diodes grown by plasma-assisted molecular beam light-emitting diodes prepared on ( 11 2 ¯ 2 ) -plane GaN J. Appl. Phys. 100, 113109 (2006); 10.1063/1.2382667 Demonstration of a semipolar ( 10 1 ¯ 3 ¯ ) In Ga N Ga N green light emitting diode Appl. Phys. Lett. 87, 231110

  2. Gallium nitride junction field-effect transistor

    DOE Patents [OSTI]

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

    1999-02-02

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

  3. Gallium nitride junction field-effect transistor

    DOE Patents [OSTI]

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

    1999-01-01

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

  4. Spontaneous emission in GaN/InGaN photonic crystal nanopillars

    E-Print Network [OSTI]

    Boyer, Edmond

    . Sigalas, "InGaN/GaN quantum-well heterostructure light-emitting diodes employing photonic crystal, "III-nitride blue and ultraviolet photonic crystal light emitting diodes," Appl. Phys. Lett. 84, 466, and H. Benisty, "Photonic-crystal GaN light-emitting diodes with tailored guided modes distribution

  5. Continuous nanoparticle generation and assembly by atmospheric pressure arc discharge

    E-Print Network [OSTI]

    Jacobs, Heiko O.

    to the manufacture of low cost printable electronics, optoelectronics, and solar cells with higher per- formance than eliminate this requirement providing a larger selection of materials including Si, Ge, GaN, and GaAs, and deposition of thin films and nanomaterials.3 Typically, a dis- tinction is made between low and atmospheric

  6. IOP PUBLISHING JOURNAL OF PHYSICS D: APPLIED PHYSICS J. Phys. D: Appl. Phys. 42 (2009) 145113 (9pp) doi:10.1088/0022-3727/42/14/145113

    E-Print Network [OSTI]

    Melnik, Roderick

    2009-01-01

    including light emitters [6­8], elements of solar cells [9], transparent conductive layers or buffer thin in electronics and optoelectronics. III­V semiconductor nano- structures, in particular GaN- and GaAs films [10] and CdTe, CdSe and CdS nanowires (NWs) based infra-red detection [11, 12]. Advances in growth

  7. Computer Physics Communications 174 (2006) 521529 www.elsevier.com/locate/cpc

    E-Print Network [OSTI]

    Rapaport, Dennis C.

    2006-01-01

    ,b a Department of Physics, Bar-Ilan University, Ramat-Gan 52900, Israel 1 b Center for Engineering Science factors are the principal contributors to this trend. The first is the growth in raw processing speed due). 1 Permanent address. little effort on the part of the software designers, whereas oth- ers require

  8. 2892 IEEE TRANSACTIONS ON POWER SYSTEMS, VOL. 29, NO. 6, NOVEMBER 2014 Optimal Power Flow in Direct Current Networks

    E-Print Network [OSTI]

    Wierman, Adam

    .g., photovoltaic panels, wind turbines, electric vehicles, electronic appliances, and fuel cells, are easier2892 IEEE TRANSACTIONS ON POWER SYSTEMS, VOL. 29, NO. 6, NOVEMBER 2014 Optimal Power Flow in Direct Current Networks Lingwen Gan and Steven H. Low, Fellow, IEEE Abstract--The optimal power flow (OPF

  9. Transphorm Takes Energy Efficiency to a New Level

    Broader source: Energy.gov [DOE]

    Transphorm, a startup partially funded by ARPA-E, develops Gallium nitride (GaN) semiconductors that could be used to make cost-effective, high-performance power converters for electric motor drives and components of solar panels and electric vehicles.

  10. Parametric Trade Study for Supersonic Bi-Directional Flying Wing

    E-Print Network [OSTI]

    Zha, Gecheng

    Parametric Trade Study for Supersonic Bi-Directional Flying Wing Jiaye Gan , Alexis Lefebvre for supersonic bi-directional flying wing(SBiDir-FW). The mission requirements for this su- personic plane on the airplane surface in order to mitigate sonic boom and improve aerodynamic efficiency. The trade study has

  11. An Integrated Symbolic and Neural Network Architecture for Machine Learning in the Domain of Nuclear Engineering

    E-Print Network [OSTI]

    Siegelmann , Hava T

    Fuel Management in Nuclear Power Plants The core of a nuclear reactor can be schematized as a grid of Nuclear Engineering Ephraim Nissan Hava Siegelmann Alex Galperin Mathematics Industrial Engineering Nuclear Engineering Bar-Ilan University Technion Ben-Gurion University Ramat-Gan, Israel Haifa, Israel

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

    E-Print Network [OSTI]

    This surface forms the starting point for Mn deposition. The Mn atomic layer was prepared by depositing MnAtomic layer structure of manganese atoms on wurtzite gallium nitride ,,0001¯... Abhijit Chinchore stage of growth. Certainly, a thin well-ordered layer of Mn atoms on GaN could be of great interest

  13. Measurements of transverse energy distributions in Au plus Au collisions at root s(NN)=200 GeV 

    E-Print Network [OSTI]

    Adams, J.; Aggarwal, MM; Ahammed, Z.; Amonett, J.; Anderson, BD; Arkhipkin, D.; Averichev, GS; Bai, Y.; Balewski, J.; Barannikova, O.; Barnby, LS; Baudot, J.; Bekele, S.; Belaga, VV; Bellwied, R.; Berger, J.; Bezverkhny, BI; Bharadwaj, S.; Bhatia, VS; Bichsel, H.; Billmeier, A.; Bland, LC; Blyth, CO; Bonner, BE; Botje, M.; Boucham, A.; Brandin, A.; Bravar, A.; Bystersky, M.; Cadman, RV; Cai, XZ; Caines, H.; Sanchez, MCD; Carroll, J.; Castillo, J.; Cebra, D.; Chajecki, Z.; Chaloupka, P.; Chattopdhyay, S.; Chen, HF; Chen, Y.; Cheng, J.; Cherney, M.; Chikanian, A.; Christie, W.; Coffin, JP; Cormier, TM; Cramer, JG; Crawford, HJ; Das, D.; Das, S.; De Moura, MM; Derevschikov, AA; Didenko, L.; Dietel, T.; Dong, WJ; Dong, X.; Draper, JE; Du, F.; Dubey, AK; Dunin, VB; Dunlop, JC; Mazumdar, MRD; Eckardt, V.; Edwards, WR; Efimov, LG; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Fachini, P.; Faivre, J.; Fatemi, R.; Fedorisin, J.; Filimonov, K.; Filip, P.; Finch, E.; Fine, V.; Fisyak, Y.; Foley, KJ; Fomenko, K.; Fu, J.; Gagliardi, Carl A.; Gans, J.; Ganti, MS; Gaudichet, L.; Geurts, F.; Ghazikhanian, V.; Ghosh, P.; Gonzalez, JE; Grachov, O.; Grebenyuk, O.; Grosnick, D.; Guertin, SM; Guo, Y.; Gupta, A.; Gutierrez, TD; Hallman, TJ; Hamed, A.; Hardtke, D.; Harris, JW; Heinz, M.; Henry, TW; Hepplemann, S.; Hippolyte, B.; Hirsch, A.; Hiort, E.; Hoffmann, GW; Huang, HZ; Huang, SL; Hughes, EW; Humanic, TJ; Igo, G.; Ishihara, A.; Jacobs, P.; Jacobs, WW; Janik, M.; Jiang, H.; Jones, PG; Judd, EG; Kabana, S.; Kang, K.; Kaplan, M.; Keane, D.; Khodyrev, VY; Kiryluk, J.; Kisiel, A.; Kislov, EM; Klay, J.; Klein, SR; Klyachko, A.; Koetke, DD; Kollegger, T.; Kopytine, M.; Kotchenda, L.; Kramer, M.; Kravtsov, P.; Kravtsov, VI; Krueger, K.; Kuhn, C.; Kulikov, AI; Kumar, A.; Kunz, CL; Kutuev, RK; Kuznetsov, AA; Lamont, MAC; Landgraf, JM; Lange, S.; Lane, F.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lehocka, S.; LeVine, MJ; Li, C.; Li, Q.; Li, Y.; Lindenbaum, SJ; Lisa, MA; Liu, F.; Liu, L.; Liu, QJ; Liu, Z.; Ljubicic, T.; Llope, WJ; Long, H.; Longacre, RS; Lopez-Noriega, M.; Love, WA; Lu, Y.; Ludlam, T.; Lynn, D.; Ma, GL; Ma, JG; Ma, YG; Magestro, D.; Mahajan, S.; Mahapatra, DP; Majka, R.; Mangotra, LK; Manweiler, R.; Margetis, S.; Markert, C.; Martin, L.; Marx, JN; Matis, HS; Matulenko, YA; McClain, CJ; McShane, TS; Meissner, F.; Melnick, Y.; Meschanin, A.; Miller, ML; Milosevich, Z.; Minaev, NG; Mironov, C.; Mischke, A.; Mishra, D.; Mitchell, J.; Mohanty, B.; Molnar, L.; Moore, CF; Mora-Corral, MJ; Morozov, DA; Morozov, V.; Munhoz, MG; Nandi, BK; Nayak, TK; Nelson, JM; Netrakanti, PK; Nikitin, VA; Nogach, LV; Norman, B.; Nurushev, SB; Odyniec, G.; Ogawa, A.; Okorokov, V.; Oldenburg, M.; Olson, D.; Pal, SK; Panebratsev, Y.; Panitkin, SY; Pavlinov, AI; Pawlak, T.; Peitzmann, T.; Perevoztchikov, V.; Perkins, C.; Peryt, W.; Petrov, VA; Phatak, SC; Picha, R.; Planinic, M.; Pluta, J.; Porile, N.; Porter, J.; Poskanzer, AM; Potekhin, M.; Potrebenikova, E.; Potukuchi, BVKS; Prindle, D.; Pruneau, C.; Putschke, J.; Rai, G.; Rakness, G.; Raniwala, R.; Raniwala, S.; Ravel, O.; Ray, RL; Razin, SV; Reichhold, D.; Reid, JG; Renault, G.; Retiere, F.; Ridiger, A.; Ritter, HG; Roberts, JB; Rogachevskiy, OV; Romero, JL; Rose, A.; Roy, C.; Ruan, L.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Savin, I.; Sazhin, PS; Schambach, J.; Scharenberg, RP; Schmitz, N.; Schroeder, LS; Schweda, K.; Seger, J.; Seyboth, P.; Shahaliev, E.; Shao, M.; Shao, W.; Sharma, M.; Shen, WQ; Shestermanov, KE; Shimanskiy, SS; Simon, F.; Singaraju, RN; Skoro, G.; Smirnov, N.; Snellings, R.; Sood, G.; Sorensen, P.; Sowinski, J.; Speltz, J.; Spinka, H. M.; Srivastava, B.; Stadnik, A.; Stanislaus, TDS; Stock, R.; Stolpovsky, A.; Strikhanov, M.; Stringfellow, B.; Suaide, AAP; Sugarbaker, E.; Suire, C.; Sumbera, M.; Surrow, B.; Symons, TJM; de Toledo, AS; Szarwas, P.; Tai, A.; Takahashi, J.; Tang, AH; Tarnowsky, T.; Thein, D.; Thomas, JH; Timoshenko, S.; Tokarev, M.; Trainor, TA; Trentalange, S.; Tribble, Robert E.; Tsai, O.; Ulery, J.; Ullrich, T.; Underwood, DG; Urkinbaev, A.; Van Buren, G.; van Leeuwen, M.; Vander Molen, AM; Varma, R.; Vasilevski, IM; Vasiliev, AN; Vernet, R.; Vigdor, SE; Viyogi, VP; Vokal, S.; Voloshin, SA; Vznuzdaev, M.; Waggoner, B.; Wang, F.; Wang, G.; Wang, G.; Wang, XL; Wang, Y.; Wang, Y.; Wang, ZM; Ward, H.; Watson, JW; Webb, JC; Wells, R.; Westfall, GD; Wetzler, A.; Whitten, C.; Wieman, H.; Wissink, SW; Witt, R.; Wood, J.; Wu, J.; Xu, N.; Xu, Z.; Xu, ZZ; Yamamoto, E.; Yepes, P.; Yurevich, VI; Zanevsky, YV; Zhang, H.; Zhang, WM; Zhang, ZP; Zolnierezuk, PA; Zoulkarneev, R.; Zoulkarneeva, Y.; Zubarev, AN.

    2004-01-01

    . Foley,4 K. Fomenko,12 J. Fu,41 C. A. Gagliardi,39 J. Gans,48 M. S. Ganti,43 L. Gaudichet,38 F. Geurts,34 V. Ghazikhanian,8 P. Ghosh,43 J. E. Gonzalez,8 O. Grachov,46 O. Grebenyuk,27 D. Grosnick,42 S. M. Guertin,8 Y. Guo,46 A. Gupta,19 T. D. Gutierrez,7...

  14. Formation of single crystalline ZnO nanotubes without catalysts and templates

    E-Print Network [OSTI]

    Geohegan, David B.

    nanotubes. GaN,1 silica,2 ZnO,3,4 and TiO2 Ref. 5 nanotubes have been synthesized by using multistep#12;Formation of single crystalline ZnO nanotubes without catalysts and templates Samuel L. Mensah January 2007; published online 13 March 2007 Oxide and nitride nanotubes have gained attention

  15. VOLUME 80, NUMBER 21 P H Y S I C A L R E V I E W L E T T E R S 25 MAY 1998 Femtosecond Four-Wave Mixing Experiments on GaAs Quantum Wells

    E-Print Network [OSTI]

    Hohng, Sung Chul

    Materialwissenschaften, Phillips-Universtät Marburg, 35032 Marburg, Germany D. H. Woo, E. K. Kim, and S. H. Kim Korea when v2 is completely below the exciton energies, with no spectral overlap with the absorption profile further extended the usage of FWM into wide band gap materials such as ZnSe [4] and GaN [5]. Most

  16. Planning Organization & Logistics Deputy Director General

    E-Print Network [OSTI]

    Adin, Ron

    " Planning Organization & Logistics Deputy Director General Tel: 03 531 8553 : Fax: 03 535 4925 : P-O.Logistics@mail.biu.ac.il Bar-Ilan University, Ramat Gan 52900, Israel · www.6. , . , . #12; " Planning Organization & Logistics Deputy Director General Tel: 03 531 8553 : Fax: 03 535

  17. Multicolor, High Efficiency, Nanotextured LEDs

    SciTech Connect (OSTI)

    Jung Han; Arto Nurmikko

    2011-09-30

    We report on research results in this project which synergize advanced material science approaches with fundamental optical physics concepts pertaining to light-matter interaction, with the goal of solving seminal problems for the development of very high performance light emitting diodes (LEDs) in the blue and green for Solid State Lighting applications. Accomplishments in the duration of the contract period include (i) heteroepitaxy of nitrogen-polar LEDs on sapphire, (ii) heteroepitaxy of semipolar (11{bar 2}2) green LEDs on sapphire, (iii) synthesis of quantum-dot loaded nanoporous GaN that emits white light without phosphor conversion, (iv) demonstration of the highest quality semipolar (11{bar 2}2) GaN on sapphire using orientation-controlled epitaxy, (v) synthesis of nanoscale GaN and InGaN medium, and (vi) development of a novel liftoff process for manufacturing GaN thin-film vertical LEDs. The body of results is presented in this report shows how a solid foundation has been laid, with several noticeable accomplishments, for innovative research, consistent with the stated milestones.

  18. Thermochronology of the Talkeetna intraoceanic arc of Alaska: Ar/Ar, UTh/He, SmNd, and LuHf dating

    E-Print Network [OSTI]

    B. R. Hacker,1 Peter B. Kelemen,2 Matthew Rioux,1,3 Michael O. McWilliams,4 Philip B. Gans,1 Peter W with simple construction histories. Citation: Hacker, B. R., P. B. Kelemen, M. Rioux, M. O. McWilliams, P. B

  19. Ar Constraints on the tectonic history and architecture of the ultrahigh-pressure Sulu orogen

    E-Print Network [OSTI]

    Hacker, Bradley R.

    orogen B. R. HACKER,1 S. R. WALLIS,2 M. O. MCWILLIAMS3 AND P. B. GANS1 1 Department of Earth Science, University of California, Santa Barbara, 93106-9630 CA, USA (hacker@geol.ucsb.edu) 2 Department of Earth-documented peak metamorphism of 650­850 °C and 4 GPa (sum- mary in Hacker, 2006) shows that this terrane

  20. The Cenozoic Tectonic History of the Calabrian Orogen, Southern Italy

    E-Print Network [OSTI]

    Shimabukuro, David Haruo

    2011-01-01

    doi:10.1029/2003GC000681. Hacker, B.R. , and Gnos, E. , TheMemoir 164, p. 301-311. Hacker, B.R. , Abers, G.A. , and187- Brocker, M. , Bieling, D. , Hacker, B. , and Gans, P. ,

  1. Robust Combiners for Software Hardening Amir Herzberg and Haya Shulman

    E-Print Network [OSTI]

    International Association for Cryptologic Research (IACR)

    Robust Combiners for Software Hardening Amir Herzberg and Haya Shulman Bar-Ilan University Department of Computer Science Ramat-Gan, 52900, Israel Abstract. All practical software hardening schemes S provided either X or Y satisfy S. We present the rst robust combiners for software hardening, specically

  2. Neurobiology of Disease Spatial and Temporal Properties of Tic-Related Neuronal

    E-Print Network [OSTI]

    Bar-Gad, Izhar

    Neurobiology of Disease Spatial and Temporal Properties of Tic-Related Neuronal Activity of Life Sciences, Bar- Ilan University, Ramat-Gan 52900, Israel Motor tics are involuntary brief muscle the pathophysiology of tics is still largely unknown, multiple lines of evidence suggest the involvement

  3. Emission and absorption cross-sections of an Er:GaN waveguide prepared with metal organic chemical vapor deposition

    E-Print Network [OSTI]

    Wang, Q.; Dahal, R.; Feng, I. W.; Lin, J. Y.; Jiang, H. X.; Hui, Rongqing

    2011-01-01

    We repost the characterization of emission and absorption cross-sections in an erbium-doped GaN waveguide prepared by metal organic chemical vapor deposition. The emission cross-section was obtained with the Füchtbauer–Ladenburg equation based...

  4. Efficiency Optimization for a Power Factor Correction (PFC) Rectifier with Gallium Nitride

    E-Print Network [OSTI]

    Paderborn, Universität

    and utilized to identify the best design by numeric optimization of switching frequency, number of turns) and to increase the power density. Despite of the comparable low switching losses of GaN transistors circuit that achieves negative voltage at switch-off with a unipolar power supply is described in Section

  5. Tunnel MOS Heterostructure Field Effect Transistor for RF Switching Applications 

    E-Print Network [OSTI]

    Rezanezhad Gatabi, Iman

    2013-06-06

    GaN RF switches are widely used in today’s communication systems. With digital communications getting more and more popular nowadays, the need for improving the performance of involved RF switches is inevitable. Designing low ON-state resistance Ga...

  6. Impact of Chemical States on the Effective Work Function of Metal Gate and High-kappa Dielectric Materials on Novel Heterostructures 

    E-Print Network [OSTI]

    Coan, Mary

    2012-10-19

    and the interface between GaN and Al2O3, HfO2 and GaON. The investigation of the effect of a heterojunction on the effective work function in a metal/high-? gate stack found that when a Ge/Si heterostructure on silicon is lightly doped and sufficiently thin...

  7. Real-Time Deferrable Load Control: Handling the Uncertainties of Renewable Generation

    E-Print Network [OSTI]

    Low, Steven H.

    -time so as to ease the incorporation of renewable energy into the grid, and so are recognized as priority deferrable loads in order to compensate for the random fluctuations of renewable energy. However, realizingReal-Time Deferrable Load Control: Handling the Uncertainties of Renewable Generation Lingwen Gan

  8. Real-Time Deferrable Load Control: Handling the Uncertainties of Renewable Generation

    E-Print Network [OSTI]

    Low, Steven H.

    Real-Time Deferrable Load Control: Handling the Uncertainties of Renewable Generation Lingwen Gan to handle the un- certainties of renewable generation. It is expected that a large number of deferrable for the random fluctuations in renewable generation. Work on deferrable load control falls into two categories

  9. Real-Time Deferrable Load Control: Handling the Uncertainties of Renewable Generation

    E-Print Network [OSTI]

    Low, Steven H.

    of renewable energy into the grid, and so are recognized as priority areas for the future smart grid by both for the random fluctuations of renewable energy. However, realizing the potential of deferrable loads re- quiresReal-Time Deferrable Load Control: Handling the Uncertainties of Renewable Generation Lingwen Gan

  10. InsideIllinoisSept. 18, 2008 Vol. 28, No. 6

    E-Print Network [OSTI]

    Bashir, Rashid

    to better their times on the campus track. Other days, the competitors hit the streets, building speed of a crash-test dummy in the department's wind tunnel. Some of the students be- gan working on the project the frontal area of the chair small, or for the racers to tuck their heads." Bleakney said some racers have

  11. J. Phys. A: Math. Gen., Vol. 10, No. 4, 1977. Printed in Great Britain. @ 1977 Numerical studies of collapsing polymers

    E-Print Network [OSTI]

    Rapaport, Dennis C.

    of collapsing polymers D C Rapaport Department of Physics, Bar-Ilan University, Ramat-Gan, Israel Received 8 November 1976 Abstract. The behaviour of a polymer dissolved in a poor solvent is studied using the self-interacting self-avoiding walk model. The properties of short polymers are generated by exact enumeration methods

  12. Molecular Cell 23, 112, July 7, 2006 2006 Elsevier Inc. DOI 10.1016/j.molcel.2006.06.008 ReviewDivergence from a Dedicated

    E-Print Network [OSTI]

    Divergence from a Dedicated Cellular Suicide Mechanism: Exploring the Evolution of Cell Death Junying Yuan1, * 1 in the nematode C. ele- gans is controlled by a simple and dedicated genetic program. This genetic program. elegans cell death gene products continue to regulate apopto- sis, they are no longer dedicated regulators

  13. Optical characteristics of nanocrystalline Al{sub x}Ga{sub 1?x}N thin films deposited by hollow cathode plasma-assisted atomic layer deposition

    SciTech Connect (OSTI)

    Goldenberg, Eda; Ozgit-Akgun, Cagla; Biyikli, Necmi; Kemal Okyay, Ali

    2014-05-15

    Gallium nitride (GaN), aluminum nitride (AlN), and Al{sub x}Ga{sub 1?x}N films have been deposited by hollow cathode plasma-assisted atomic layer deposition at 200?°C on c-plane sapphire and Si substrates. The dependence of film structure, absorption edge, and refractive index on postdeposition annealing were examined by x-ray diffraction, spectrophotometry, and spectroscopic ellipsometry measurements, respectively. Well-adhered, uniform, and polycrystalline wurtzite (hexagonal) GaN, AlN, and Al{sub x}Ga{sub 1?x}N films were prepared at low deposition temperature. As revealed by the x-ray diffraction analyses, crystallite sizes of the films were between 11.7 and 25.2?nm. The crystallite size of as-deposited GaN film increased from 11.7 to 12.1 and 14.4?nm when the annealing duration increased from 30?min to 2?h (800?°C). For all films, the average optical transmission was ?85% in the visible (VIS) and near infrared spectrum. The refractive indices of AlN and Al{sub x}Ga{sub 1?x}N were lower compared to GaN thin films. The refractive index of as-deposited films decreased from 2.33 to 2.02 (??=?550?nm) with the increased Al content x (0???x???1), while the extinction coefficients (k) were approximately zero in the VIS spectrum (>400?nm). Postdeposition annealing at 900?°C for 2?h considerably lowered the refractive index value of GaN films (2.33–1.92), indicating a significant phase change. The optical bandgap of as-deposited GaN film was found to be 3.95?eV, and it decreased to 3.90?eV for films annealed at 800?°C for 30?min and 2?h. On the other hand, this value increased to 4.1?eV for GaN films annealed at 900?°C for 2?h. This might be caused by Ga{sub 2}O{sub 3} formation and following phase change. The optical bandgap value of as-deposited Al{sub x}Ga{sub 1?x}N films decreased from 5.75 to 5.25?eV when the x values decreased from 1 to 0.68. Furthermore, postdeposition annealing did not affect the bandgap of Al-rich films.

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

    SciTech Connect (OSTI)

    Patibandla, Nag; Agrawal, Vivek

    2012-12-01

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

  15. By airplane: The bus shuttle 'Airport

    E-Print Network [OSTI]

    at the upper left. * The naldoCard is a prepaid card for use in the buses of the naldo network, including

  16. Massachusetts state airport system plan forecasts.

    E-Print Network [OSTI]

    Mathaisel, Dennis F. X.

    This report is a first step toward updating the forecasts contained in the 1973 Massachusetts State System Plan. It begins with a presentation of the forecasting techniques currently available; it surveys and appraises the ...

  17. PITTSBURGH AIRPORT MARRIOTT HOTEL FLOOR PLAN

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

    10:45 - 12:00 p.m Intermediate Temperature Electrogenerative Cells for Flexible Cogeneration of Power and Liquid Fuel Greg Tao, Materials & Systems Research, Inc. Liquid Fuels...

  18. AirportRoad State St. (SR 26)

    E-Print Network [OSTI]

    Pittendrigh, Barry

    24 21 22 Residence facilities To SIML HOVD Purdue M all PGU TEL CARY MOLL IAF MACK LAMB STDM STEW PMU

  19. COMPARING THE VANCOUVER INTERNATIONAL AIRPORT AUTHORITY'S

    E-Print Network [OSTI]

    prescribed authorities to conduct environmental impact assessments (EIAs) of projects carried out on federal environmental management. The International Association for Impact Assessment's (IAIA) Principles for EIA Best if the proposed CEAA regulations come into force. Keywords: Environmental impact assessment; best practice

  20. Airports - Local Information - Radiation Effects Facility / Cyclotron

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O O D S TA I N P A T T E R N AManagedInstitute / Texas A&M

  1. Beijing Capital International Airport | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIX E LISTStar Energy LLC Jump to:Greece:Bajo en Carbono,BeWind PowerBeemerBeiyi

  2. Microsoft Word - Airport_EA_Final.doc

    National Nuclear Security Administration (NNSA)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield Municipal GasAdministration Medal01 Sandia NationalSecurityNuclearH-canyon |I6 Page515 Final

  3. Airports & Lodging | Savannah River Ecology Laboratory

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory of raregovAboutRecovery Act RecoveryTechnologiesAffiliates JCESR has

  4. Impact of electron irradiation on electron holographic potentiometry

    SciTech Connect (OSTI)

    Park, J. B.; Niermann, T.; Lehmann, M. [Technische Universität Berlin, Institut für Optik und Atomare Physik, Straße des 17. Juni 135, 10623 Berlin (Germany); Berger, D. [Technische Universität Berlin, Zentraleinrichtung für Elektronenmikroskopie, Strae des 17. Juni 135, 10623 Berlin (Germany); Knauer, A.; Weyers, M. [Ferdinand-Braun-Institut, Leibnitz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12489 Berlin (Germany); Koslow, I.; Kneissl, M. [Ferdinand-Braun-Institut, Leibnitz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12489 Berlin (Germany); Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstr. 36, 10623 Berlin (Germany)

    2014-09-01

    While electron holography in the transmission electron microscope offers the possibility to measure maps of the electrostatic potential of semiconductors down to nanometer dimensions, these measurements are known to underestimate the absolute value of the potential, especially in GaN. We have varied the dose rates of electron irradiation over several orders of magnitude and observed strong variations of the holographically detected voltages. Overall, the results indicate that the electron beam generates electrical currents within the specimens primarily by the photovoltaic effect and due to secondary electron emission. These currents have to be considered for a quantitative interpretation of electron holographic measurements, as their negligence contributes to large parts in the observed discrepancy between the measured and expected potential values in GaN.

  5. Search for 14.4 keV solar axions emitted in the M1-transition of 57Fe nuclei with CAST

    E-Print Network [OSTI]

    CAST Collaboration; S. Andriamonje; S. Aune; D. Autiero; K. Barth; A. Belov; B. Beltrán; H. Bräuninger; J. M. Carmona; S. Cebrián; J. I. Collar; T. Dafni; M. Davenport; L. Di Lella; C. Eleftheriadis; J. Englhauser; G. Fanourakis; E. Ferrer-Ribas; H. Fischer; J. Franz; P. Friedrich; T. Geralis; I. Giomataris; S. Gninenko; H. Gómez; M. Hasinoff; F. H. Heinsius; D. H. H. Hoffmann; I. G. Irastorza; J. Jacoby; K. Jakov?i?; D. Kang; K. Königsmann; R. Kotthaus; M. Kr?mar; K. Kousouris; M. Kuster; B. Laki?; C. Lasseur; A. Liolios; A. Ljubi?i?; G. Lutz; G. Luzón; D. Miller; J. Morales; A. Ortiz; T. Papaevangelou; A. Placci; G. Raffelt; H. Riege; A. Rodríguez; J. Ruz; I. Savvidis; Y. Semertzidis; P. Serpico; L. Stewart; J. Vieira; J. Villar; J. Vogel; L. Walckiers; K. Zioutas

    2009-12-04

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

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

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

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

    2009-01-01

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

  7. Inversion by metalorganic chemical vapor deposition from N- to Ga-polar gallium nitride and its application to multiple quantum well light-emitting diodes

    SciTech Connect (OSTI)

    Hosalli, A. M.; Van Den Broeck, D. M.; Bedair, S. M. [Department of Electrical and Computer Engineering, NCSU, Raleigh, North Carolina 27695 (United States)] [Department of Electrical and Computer Engineering, NCSU, Raleigh, North Carolina 27695 (United States); Bharrat, D.; El-Masry, N. A. [Department of Material Science and Engineering, NCSU, Raleigh, North Carolina 27695 (United States)] [Department of Material Science and Engineering, NCSU, Raleigh, North Carolina 27695 (United States)

    2013-12-02

    We demonstrate a metalorganic chemical vapor deposition growth approach for inverting N-polar to Ga-polar GaN by using a thin inversion layer grown with high Mg flux. The introduction of this inversion layer allowed us to grow p-GaN films on N-polar GaN thin film. We have studied the dependence of hole concentration, surface morphology, and degree of polarity inversion for the inverted Ga-polar surface on the thickness of the inversion layer. We then use this approach to grow a light emitting diode structure which has the MQW active region grown on the advantageous N-polar surface and the p-layer grown on the inverted Ga-polar surface.

  8. Neutron detection using boron gallium nitride semiconductor material

    SciTech Connect (OSTI)

    Atsumi, Katsuhiro [Department of Electrical and Electronic Engineering, Graduate School of Engineering, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8561 (Japan); Inoue, Yoku; Nakano, Takayuki, E-mail: ttnakan@ipc.shizuoka.ac.jp [Department of Electrical and Materials Science, Graduate School of Engineering, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8561 (Japan); Mimura, Hidenori; Aoki, Toru [Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8011 (Japan)

    2014-03-01

    In this study, we developed a new neutron-detection device using a boron gallium nitride (BGaN) semiconductor in which the B atom acts as a neutron converter. BGaN and gallium nitride (GaN) samples were grown by metal organic vapor phase epitaxy, and their radiation detection properties were evaluated. GaN exhibited good sensitivity to ?-rays but poor sensitivity to ?-rays. Moreover, we confirmed that electrons were generated in the depletion layer under neutron irradiation. This resulted in a neutron-detection signal after ?-rays were generated by the capture of neutrons by the B atoms. These results prove that BGaN is useful as a neutron-detecting semiconductor material.

  9. Hybrid Pd/Fe{sub 3}O{sub 4} nanowires: Fabrication, characterization, optical properties and application as magnetically reusable catalyst for the synthesis of N-monosubstituted ureas under ligand-free conditions

    SciTech Connect (OSTI)

    Nasrollahzadeh, Mahmoud; Azarian, Abbas; Ehsani, Ali; Sajadi, S.Mohammad; Babaei, Ferydon

    2014-07-01

    Highlights: • Preparation of Pd/Fe{sub 3}O{sub 4} nanowires as magnetically reusable catalysts. • The optical properties of the catalyst were studied using Gans theory. • N-arylation of benzylurea and in situ hydrogenolysis of 1-benzyl-3-arylureas. - Abstract: This paper reports the synthesis and use of Pd/Fe{sub 3}O{sub 4} nanowires, as magnetically separable catalysts for ligand-free amidation coupling reactions of aryl halides with benzylurea under microwave irradiation. Then, the in situ hydrogenolysis of the products was performed to afford the N-monosubstituted ureas from good to excellent yields. This method has the advantages of high yields, simple methodology and easy work up. The catalyst can be recovered by using a magnet and reused several times without significant loss of its catalytic activity. The catalyst was characterized using the powder XRD, SEM, EDS and UV–vis spectroscopy. Experimental absorbance spectra was compared with results from the Gans theory.

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

    SciTech Connect (OSTI)

    Ian Ferguson; Chris Summers

    2009-12-31

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

  11. Dysprosium doped cadmium oxide: A gateway material for mid-infrared plasmonics

    E-Print Network [OSTI]

    Curtarolo, Stefano

    Carolina 27695, USA Supplementary information Figure 1. Transport data for CdO:Dy grown on MgO (111 Figure 2. Transport data for CdO:Dy grown on GaN (002) substrates summarizing carrier conc. (cm-3 ) and carrier mobility () as a function of [Dy]. Figure 3. Transport data for CdO:Dy grown on Al2O3 (006

  12. Amber light-emitting diode comprising a group III-nitride nanowire active region

    DOE Patents [OSTI]

    Wang, George T.; Li, Qiming; Wierer, Jr., Jonathan J.; Koleske, Daniel

    2014-07-22

    A temperature stable (color and efficiency) III-nitride based amber (585 nm) light-emitting diode is based on a novel hybrid nanowire-planar structure. The arrays of GaN nanowires enable radial InGaN/GaN quantum well LED structures with high indium content and high material quality. The high efficiency and temperature stable direct yellow and red phosphor-free emitters enable high efficiency white LEDs based on the RGYB color-mixing approach.

  13. Structural and optical properties of InGaN–GaN nanowire heterostructures grown by molecular beam epitaxy

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

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

    2011-01-01

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

  14. Downloaded 07 Feb 2012 to 128.180.65.141. Redistribution subject to AIP license or copyright; see http://jap.aip.org/about/rights_and_permissions Improvement in spontaneous emission rates for InGaN quantum

    E-Print Network [OSTI]

    Gilchrist, James F.

    ) The spontaneous emission characteristics of green- and red-emitting InGaN quantum wells (QWs) on ternary In compared with those of InGaN QWs on GaN templates. For green- and red-emitting InGaN QWs on In0.15Ga0.85N with enhanced spontaneous emission rates, as well as reduced compressive strain, applicable for green- and red

  15. 2570 IEEE TRANSACTIONS ON ELECTRON DEVICES, VOL. 50, NO. 12, DECEMBER 2003 [1] J. K. Ho, C. S. Jong, C. C. Chiu, C. N. Huang, K. K. Shih, L. C. Chen,

    E-Print Network [OSTI]

    Hornsey, Richard

    light emitting diodes," IEEE J. Quantum. Electron., vol. 38, pp. 446­450, May 2002. [3] Y. L. Li, E. F-operation voltage of InGaN/ GaN light-emitting diodes by using a Mg-doped Al Ga N/GaN superlattice," IEEE Electron. Hirata, "Room-temperature operation at 333 nm of Al Ga N/ Al Ga N quantum-well light-emitting diodes

  16. Studies on the metabolism of juvenile hormone in the adult male Hyalophora cecropia (L.) (Lepidoptera, Saturniidae) 

    E-Print Network [OSTI]

    Shirk, Paul David

    1975-01-01

    extent exchange of the methyl ester group with the S-methyl group of methionine. ACKNCWLEDGEMENTS This work was supported by Grant No. BMS7201892-A03 from the National Science Foundation to Dr. H. Roller and Dr . K. H. Dahm. I wish to thank... INTRODUCTION. MATERIALS AND METHODS. Animals Chemicals. Radi o chemi ca l s 1'nj ection of Animals. 2'he Surgical Removal of Berold 's Ongan. . . . . Or gan Cul tuz'e Extz'action 1. . . . . . , . . . . . . . . . . . . . . . . . . . . , . Ez tvacti on...

  17. [5] J. C. Vartuli, K. D. Schmitt, C. T. Kresge, W. J. Roth, M. E. Leonowicz, S. B. McCullen, S. D. Hellring, J. S. Beck, J. L. Schlenker, D. H. Olson,

    E-Print Network [OSTI]

    Zhou, Chongwu

    widely used in solar cells and organic light-emitting diodes.[13±14] More importantly, In2O3 films have Ge,[1] ZnO,[2] Si,[4±5] GaN,[9] and GaAs,[10] which were then employed to construct such exciting ablation of an indium-containing target. While catalysts made of a thin gold film produced In2O3 nanowire

  18. Strain versus Dislocation Model for Understanding the Heteroepitaxial Growth of Jian Shi and Xudong Wang*

    E-Print Network [OSTI]

    Wang, Xudong

    light-emitting diodes,1,2 solid state lasers,3,4 transistors,5­8 transducers,6,9,10 solar cells,11 configuration would poten- tially offer higher performance comparing to conventional 2D thin film devices.17 on GaAs or InGaAs substrates,19 GaN NWs on SiC substrates,20 and so on. How to grow uniform, well

  19. ZnO Nanotubes Grown at Low Temperature Using Ga as Catalysts and Their Enhanced Photocatalytic Activities

    E-Print Network [OSTI]

    Wang, Zhong L.

    substantial reports on tubular nanostructures of various materials including GaN,12 MoS2,13 TiO2,14 SiO2,15 AlZnO Nanotubes Grown at Low Temperature Using Ga as Catalysts and Their Enhanced PhotocatalyticVed: April 8, 2009 We report the synthesis of ZnO nanotubes grown via the Ga-catalyzed vapor transport method

  20. Smooth cubic commensurate oxides on gallium nitride

    SciTech Connect (OSTI)

    Paisley, Elizabeth A.; Gaddy, Benjamin E.; LeBeau, James M.; Shelton, Christopher T.; Losego, Mark D.; Mita, Seiji; Collazo, Ramón; Sitar, Zlatko; Irving, Douglas L.; Maria, Jon-Paul; Biegalski, Michael D.; Christen, Hans M.

    2014-02-14

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

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

    SciTech Connect (OSTI)

    Chowdhury, S; Mishra, UK

    2013-10-01

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

  2. Strain relaxation of thick (11–22) semipolar InGaN layer for long wavelength nitride-based device

    SciTech Connect (OSTI)

    Kim, Jaehwan; Min, Daehong; Jang, Jongjin; Lee, Kyuseung; Chae, Sooryong; Nam, Okhyun, E-mail: ohnam@kpu.ac.kr [Advanced Photonics Research Center/LED Technology Center, Department of Nano-Optical Engineering, Korea Polytechnic University, 237, Sangidaehak-ro, Siheung-si, Gyeonggi-do 429-793 (Korea, Republic of)

    2014-10-28

    In this study, the properties of thick stress-relaxed (11–22) semipolar InGaN layers were investigated. Owing to the inclination of growth orientation, misfit dislocations (MDs) occurred at the heterointerface when the strain state of the (11–22) semipolar InGaN layers reached the critical point. We found that unlike InGaN layers based on polar and nonpolar growth orientations, the surface morphologies of the stress-relaxed (11–22) semipolar InGaN layers did not differ from each other and were similar to the morphology of the underlying GaN layer. In addition, misfit strain across the whole InGaN layer was gradually relaxed by MD formation at the heterointerface. To minimize the effect of surface roughness and defects in GaN layers on the InGaN layer, we conducted further investigation on a thick (11–22) semipolar InGaN layer grown on an epitaxial lateral overgrown GaN template. We found that the lateral indium composition across the whole stress-relaxed InGaN layer was almost uniform. Therefore, thick stress-relaxed (11–22) semipolar InGaN layers are suitable candidates for use as underlying layers in long-wavelength devices, as they can be used to control strain accumulation in the heterostructure active region without additional influence of surface roughness.

  3. 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.

  4. Continuous Commissioning® of the Dallas/Fort Worth International Airport 

    E-Print Network [OSTI]

    Yazdani, B.; Schroeder, F.; Kramer, L.; Baltazar, J. C.; Turner, W. D.; Wei, G.; Deng, S.; Henson, R.; Dennis, J. R.; T., R.

    2008-01-01

    savings from the CC work. The savings are approximately $60,000 (?40,000) for nine months. Projected 12-month savings are $80,000 (?53,000), representing a savings of approximately $1 per square foot per year (?6.2/m 2 per year). There are still... load causes this building to ?peak? at night. The savings from the CC process are in excess of 18% of the total building energy consumption, including lighting. The dollar savings amounted to about $0.80 per ft2 or ?5.50 per m2). DFW...

  5. Energy Management Practices at Dalls/Fort Worth International Airport 

    E-Print Network [OSTI]

    Dennis, J. R.

    2013-01-01

    ? Energy & Utilities Services Business Unit ? Energy Management Section ? Energy Manager ? Energy Engineer ? Energy Analyst ? Designer (CADD and GIS Support) ? Electrical Supervisor (27 employees) ? SEAMS Scheduler Energy Management Mission..., October 9, 2013 Supply-Side Management (cont.) ? Environmental Stewardship ? Electricity ? Onsite Renewable ? Wind ? Economically, geographically and operationally not practical ? Solar ? Economically not practical unless heavily subsidized...

  6. Federal Aviation Administration's Airport Capital Improvement Program Development Process

    E-Print Network [OSTI]

    Tener, Scott D.

    2009-12-18

    annual itinerant operations by critical aircraft, crosswind runway needed for 95% wind coverage, parallel taxiways needed for runway sight distance, instrument approach procedure, eliminate runway back taxi, waiting list, etc. • Cost Estimate... annual itinerant operations by critical aircraft, crosswind runway needed for 95% wind coverage, parallel taxiways needed for runway sight distance, instrument approach procedure, eliminate runway back taxi, waiting list, etc. • Cost Estimate...

  7. Crowne Plaza Suites MSP Airport - Mall of America

    Office of Environmental Management (EM)

    * Kevin Leuer, Minnesota Homeland Security and Emergency Management * Andrew Doyle, Baltimore Fire Department * Viktoria Mitlyng, U.S. Nuclear Regulatory Commission THURSDAY, MAY...

  8. Crowne Plaza Suites MSP Airport - Mall of America

    Office of Environmental Management (EM)

    * Kevin Leuer, Minnesota Homeland Security and Emergency Management * Andrew Doyle, Baltimore Fire Department * Viktoria Mitlyng, U.S. Nuclear Regulatory Commission Thursday, May...

  9. New airport liquid analysis system undergoes testing at Albuquerque...

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

    Security, the MagViz system is a new, ultra-low-field MRI approach first designed for brain imaging, but with a unique variation. Given a container of something that shouldn't be...

  10. Low-altitude atmospheric turbulence around an airport 

    E-Print Network [OSTI]

    Cass, Stanley Dale

    1972-01-01

    speed and the average wind speed computed over an entire run (approximately 1 hr). iv Profiles of wind speed were approximately logarithmic, but profiles of turbulent energy showed a large increase in the wake of large obstructions. Spectra of wind... from u 30-sec averages 56 57 28 Spectra of accelerometer and wind data for same period 59 LIST OF SYMBOLS Symbol Definition Exchange coefficient for momentum Height Time Kinetic energy Average kinetic energy of turbulence u' + v'2 + w' (' 2...

  11. Innovative Design Concept for the New Bangkok International Airport, NBIA 

    E-Print Network [OSTI]

    Kessling, W.; Holst, S.; Schuler, M.

    2004-01-01

    using photovoltaic modules covering a surface area of 55,000 m² for the immediate generation of electric power in combination with an electrically powered compression chiller system was compared to other concepts under the aspect of economy. Fig. 17... that the concept will work even if flight schedules are drastically changed. The building has a maximum cooling demand of 44 MW, where a third is covered by radiant floor cooling, fresh air conditioning and return air cooling respectively. With pre...

  12. Microsoft PowerPoint - Morgantown Muncipal Airport to NETL Morgantown...

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

    stop turn RIGHT onto COLLINS FERRY RD. 6. Proceed 0.5 miles through traffic light. On RIGHT- Arrive US DEPARTMENT OF ENERGY. 3610 Collins Ferry RD. Morgantown, WV 26505....

  13. Alternative Fuels Data Center: Airport Shuttles Run on Propane

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O O D S TA I NLoans The Oregon Department of EnergyASTMAirport

  14. Alternative Fuels Data Center: Colorado Airport Relies on Natural Gas

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O O D S TA I NLoans TheCountyCities MakeFueling Stations

  15. Alternative Fuels Data Center: Dallas Airport Operates With Alternative

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O O D S TA I NLoans TheCountyCitiesDriving FutureFuels

  16. DOE - Office of Legacy Management -- Milwaukee Airport - WI 04

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield Municipal Gas &SCE-SessionsSouth Dakota Edgemont,Manufacturing - OHSelling Corp - CTMillMilwaukee

  17. DOE - Office of Legacy Management -- St Louis Airport - MO 01

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield Municipal Gas &SCE-SessionsSouth DakotaRobbins and Myers Co - OH 51SavannahMillKSAirport - MO 01

  18. DOE - Office of Legacy Management -- St Louis Airport Site Vicinity

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield Municipal Gas &SCE-SessionsSouth DakotaRobbins and Myers Co - OH 51SavannahMillKSAirport - MO

  19. Advance in bottle scanning could enhance airport security and benefit

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room News Publications Traditional Knowledge KiosksAboutHelp & Reference Users AdvAnced

  20. 01-04519B_OR_Knox_AirportMap.ai

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory ofDidDevelopmentataboutScalable Framework forProtocolsChattanooga (I-75)

  1. Tonopah Airport Solar Power Plant | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION JEnvironmental Jump to:EA EISTJThin Film Solar TechnologiesCFR 1201Energy JumpToltecTongue

  2. New San Antonio Airport Terminal Generating Clean Power | Department of

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirleyEnergyTher i nAand DOEDepartmentNew Jersey is homeAdvanced Stages ofat Hanford Site

  3. Airport Road Addition, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIX ECoop IncIowaWisconsin: Energy ResourcesAir Quality Jump to:Airforce Wind

  4. Airport Road, Wyoming: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIX ECoop IncIowaWisconsin: Energy ResourcesAir Quality Jump to:Airforce WindRoad, Wyoming:

  5. Prescott Airport Solar Plant Solar Power Plant | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIXsourceII JumpQuarterly SmartDB-2, BluePoulsen Hybrid,Areas- CovePrescience

  6. LEDs Ready for Takeoff at Louisiana Airport | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious RankADVANCED MANUFACTURING OFFICE INDUSTRIALU.S. DepartmentJeanKeyLANL SustainableRoadway Lighting LEDLEDLEDs

  7. EECBG Success Story: LEDs Ready for Takeoff at Louisiana Airport |

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:FinancingPetroleum Based|Department of EnergyDepartment ofDepartment of Energy LEDs Ready

  8. EECBG Success Story: New San Antonio Airport Terminal Generating Clean

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:FinancingPetroleum Based|Department of EnergyDepartment ofDepartmentDepartment ofDepartment

  9. Philadelphia International Airport Apron Lighting: LED System Performance

    Energy Savers [EERE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousMathematicsEnergyInterested PartiesBuilding energy codesPhiladelhia Gas Works (PGW) Doe Furnace RuleDatain

  10. NNSA, Romania Launch Radiation Detection System at International Airport

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformationJessework usesof EnergyY-12 National SecurityDevelopment Flight Testnear

  11. New airport liquid analysis system undergoes testing at Albuquerque

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformationJessework usesofPublications64 2.251 2.211New SpeciesNewNational

  12. III-nitride quantum cascade detector grown by metal organic chemical vapor deposition

    SciTech Connect (OSTI)

    Song, Yu, E-mail: yusong@princeton.edu; Huang, Tzu-Yung; Badami, Pranav; Gmachl, Claire [Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08540 (United States); Bhat, Rajaram; Zah, Chung-En [Corning Incorporated, Corning, New York 14831 (United States)

    2014-11-03

    Quantum cascade (QC) detectors in the GaN/Al{sub x}Ga{sub 1?x}N material system grown by metal organic chemical vapor deposition are designed, fabricated, and characterized. Only two material compositions, i.e., GaN as wells and Al{sub 0.5}Ga{sub 0.5}N as barriers are used in the active layers. The QC detectors operates around 4??m, with a peak responsivity of up to ?100??A/W and a detectivity of up to 10{sup 8} Jones at the background limited infrared performance temperature around 140?K.

  13. Structure and strain-relaxation effects of defects in InxGa1-xN epilayers

    E-Print Network [OSTI]

    Rhode, S. L.; Fu, W. Y.; Moram, M. A.; Massabuau, F. C.-P.; Kappers, M. J.; McAleese, C.; Oehler, F.; Humphreys, C. J.; Dusane, R. O.; Sahonta, S.-L.

    2014-09-10

    , Mumbai, 400076, India *sr583@cam.ac.uk a) S. L. Rhode and W. Y. Fu contributed equally to this work. Abstract The formation of trench-defects is observed in 160 nm-thick InxGa1-xN epilayers with x ? 0.20, grown on GaN on (0001) sapphire substrates... -resolution X-ray diffraction was performed in a Philips X’ Pert diffractometer using Cu K?1 radiation with a double-bounce Ge (220) asymmetric monochromator and a double- bounce analyser. Reciprocal space maps (RSMs) were recorded for the symmetric 0006...

  14. Atom probe tomography characterisation of a laser diode structure grown by molecular beam epitaxy

    E-Print Network [OSTI]

    Bennett, Samantha; Smeeton, Tim; Saxey, David; Smith, George; Hooper, Stewart; Heffernan, Jonathan; Humphreys, Colin; Oliver, Rachel

    2012-03-06

    ) and laser diodes (LDs) fabricated from gallium nitride (GaN) and the InxGa1-xN and AlyGa1-yN alloys are used in diverse technologies including lighting, televisions, mobile phones, optical storage systems and entertainment centers. The mass- market impact... silicon was used as the n-type dopant and bis-(cyclopentadienyl) magnesium (Cp2Mg) was used as the magnesium source for the p-type doping. All of the layers below the In0.18Ga0.82N QW were grown using ammonia as the source of nitrogen, the ammonia...

  15. Two-dimensional electron gas in monolayer InN quantum wells

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

    Pan, Wei; Dimakis, Emmanouil; Wang, George T.; Moustakas, Theodore D.; Tsui, Daniel C.

    2014-11-24

    We report in this letter experimental results that confirm the two-dimensional nature of the electron systems in monolayer InN quantum wells embedded in GaN barriers. The electron density and mobility of the two-dimensional electron system (2DES) in these InN quantum wells are 5×1015 cm-2 and 420 cm2 /Vs, respectively. Moreover, the diagonal resistance of the 2DES shows virtually no temperature dependence in a wide temperature range, indicating the topological nature of the 2DES.

  16. Increased pump acceptance bandwidth in spontaneous parametric downconversion process using Bragg reflection waveguides

    E-Print Network [OSTI]

    K. Thyagarajan; R. Das; O. Alibart; M. de Micheli; D. B. Ostrowsky; S. Tanzilli

    2009-04-11

    In this paper we show that by suitably tailoring the dispersion characteristics of a Bragg reflection waveguide (BRW) mode, it is possible to achieve efficient photon pair generation over a large pump bandwidth while maintaining narrow signal bandwidth. The structure proposed consists of a high index core BRW with a periodically poled GaN core and periodically stratified cladding made up of alternate layers of $Al_{0.02}Ga_{0.98}N$ and $Al_{0.45}Ga_{0.55}N$. Such photon-pair generators should find applications in realizing compact and stable sources for quantum information processing.

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

    SciTech Connect (OSTI)

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

    2014-12-15

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

  18. Observations of Rabi oscillations in a non-polar InGaN quantum dot

    E-Print Network [OSTI]

    Reid, Benjamin P. L.; Kocher, Claudius; Zhu, Tongtong; Oehler, Fabrice; Emery, Robert; Chan, Christopher C. S.; Oliver, Rachel A.; Taylor, Robert A.

    2014-07-03

    . A pattern of such apertures was sufficient to enable optical isolation of single quantum dots. The samples were mounted in a continuous helium flow cryostat (Janis ST-500) with a feedback loop temperature controller (Lakeshore 331) enabling cooling... to sustain excitonic emission at high temperatures, evidenced by single photon emission at 200K from InGaN [8] and at 300K from GaN quantum dots [9]. Demonstration of coherent control of quantum dot qubit states in the III-nitride system has been hampered...

  19. Wetlands protection acts: a closer look 

    E-Print Network [OSTI]

    Linton, Margaret Temple

    1983-01-01

    of project. Recommended: Delaware (C), and Oregon (C). Required: New Jersey (C, D), and Pennsylvania (C, D). Im act of Su ort1n Structures Only Delaware specifically requests that any impact of support1ng structures or other support facilities associated... or impact the project/activity will have on the sur- rounding or local areas. Recommended: Mich1gan, Maryland, M1ssissippi, Delaware, South Required: Carolina, Virgin1a, and New York. Pennsylvania. Proximit to Other Waterwa s Under this criter1on...

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

    SciTech Connect (OSTI)

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

    2012-07-09

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

  1. Subjects: Trematoda and Trematode Diseases, Part 6: Supergenera And Genera N-Q 

    E-Print Network [OSTI]

    Doss, Mildred A.; Roach, Katharine F.; Breen, Virginia L.

    1967-01-01

    .;Hadlow, W.J. ; & Hughes,L.E., 1954a,336(patho- genicity of Neorickettsia helmintheca). --Price, E. W., 1929j,866-867;1929a,290 (syn.:Distomulum oregonensis). ?Senger, ?.?. ; & Neiland, ?. A. , 1955a, 638(Mus- tela vison;Oregon). - -Shaw, J. N. ;Simms, B....;Higginbotham, J. W.; & Clary, J. W., 1941a, 38;1942a, 123(Natrix sipedon;Michi- gan). --Skrjabin, K. I. ; & Antipin, D. N. , 1957a,558,fig. 169. NATRIODERINAE Yamaguti, S. , 1958a, 434. NAVICULARIA Mendheim, ?. , 1943a, 175, 207-210,. 259 (Echinostomatidae...

  2. Graphene/GaN diodes for ultraviolet and visible photodetectors

    SciTech Connect (OSTI)

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

    2014-08-18

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

  3. Nanoscale Josephson Devices

    E-Print Network [OSTI]

    Bell, Chris

    , ferromagnetically (aligned ferromagnetic layers) FIB Focused Ion Beam GL Ginzburg-Landau GPIB General Purpose Interface Bus GMR Giant Magnetoresistance HTS High Temperature Superconductor I Insulator LED Light Emitting Diode LTS Low Temperature Superconductor MR... . The fabrication of intrinsic Josephson junctions in the high temperature superconductor Tl2Ba2CaCu2O8 will then be discussed, as well as Nb/MoSi2/Nb junctions, superconducting quantum interference devices, and finally GaN light emitting diodes. The work on Tl2Ba2...

  4. How much better are InGaN/GaN nanodisks than quantum wells—Oscillator strength enhancement and changes in optical properties

    SciTech Connect (OSTI)

    Zhang, Lei; Hill, Tyler A.; Deng, Hui E-mail: peicheng@umich.edu; Lee, Leung-Kway; Teng, Chu-Hsiang; Ku, Pei-Cheng E-mail: peicheng@umich.edu

    2014-02-03

    We show over 100-fold enhancement of the exciton oscillator strength as the diameter of an InGaN nanodisk in a GaN nanopillar is reduced from a few micrometers to less than 40?nm, corresponding to the quantum dot limit. The enhancement results from significant strain relaxation in nanodisks less than 100?nm in diameter. Meanwhile, the radiative decay rate is only improved by 10 folds due to strong reduction of the local density of photon states in small nanodisks. Further increase in the radiative decay rate can be achieved by engineering the local density of photon states, such as adding a dielectric coating.

  5. Rapid precipitation in an Al0.5CrFeCoNiCu high entropy alloy

    E-Print Network [OSTI]

    Jones, N. G.; Christofidou, K. A.; Stone, H. J.

    2015-02-03

    , sluggish. 9 Acknowledgements: The authors would like to acknowledge support from the EPSRC / Rolls-Royce Strategic Partnership under EP/H500375/1, EP/M005607/1 (NGJ & HJS) and EP/H022309/1 (KAC). References: 1. J. Yeh, S. Chen, S. Lin, J. Gan, T... and Wear Resistance for Thermal Spray Coating', Advanced Engineering Materials, 2004, 6(12), 74-78. 11. Y. Chen, T. Duval, U. Hung, J. Yeh, and H. Shih: 'Microstructure and electrochemical properties of high entropy alloys - a comparison with type-304...

  6. Epitaxial growth of aligned AlGalnN nanowires by metal-organic chemical vapor deposition

    DOE Patents [OSTI]

    Han, Jung (Woodbridge, CT); Su, Jie (New Haven, CT)

    2008-08-05

    Highly ordered and aligned epitaxy of III-Nitride nanowires is demonstrated in this work. <1010> M-axis is identified as a preferential nanowire growth direction through a detailed study of GaN/AlN trunk/branch nanostructures by transmission electron microscopy. Crystallographic selectivity can be used to achieve spatial and orientational control of nanowire growth. Vertically aligned (Al)GaN nanowires are prepared on M-plane AlN substrates. Horizontally ordered nanowires, extending from the M-plane sidewalls of GaN hexagonal mesas or islands demonstrate new opportunities for self-aligned nanowire devices, interconnects, and networks.

  7. Fresnel filtering in lasing emission from scarred modes of wave-chaotic optical resonators

    E-Print Network [OSTI]

    N. B. Rex; H. E. Tureci; H. G. L. Schwefel; R. K. Chang; A. Douglas Stone

    2001-07-25

    We study lasing emission from asymmetric resonant cavity (ARC) GaN micro-lasers. By comparing far-field intensity patterns with images of the micro-laser we find that the lasing modes are concentrated on three-bounce unstable periodic ray orbits, i.e. the modes are scarred. The high-intensity emission directions of these scarred modes are completely different from those predicted by applying Snell's law to the ray orbit. This effect is due to the process of ``Fresnel filtering'' which occurs when a beam of finite angular spread is incident at the critical angle for total internal reflection.

  8. Ya, Ya/Yes, Ye: A Play Concerning an Encounter Between Vietnamese Culture and Western Medicine 

    E-Print Network [OSTI]

    Nguyen, Kim T

    2013-02-22

    the coffee table): What happened? Did you spill coffee on yourself? (hands paper towels to Grandfather) Grandfather (speaking in llietnamese, but translation is seen overhead): Khong. Ong di den quan An de mua chut cafe, va 0 d6 c6 vAi churn kho khan... linh no tihn gan va dut tach cafe cga ong. No co tach cafe roi rto len ong. Sau do, no bo 30 di voi du a ban cua no. ("He was talking, but I couldn't understand what he was saying. Suddenly, he reached over and grabbed my cup of coffee. The boy...

  9. Cubic nitride templates

    DOE Patents [OSTI]

    Burrell, Anthony K; McCleskey, Thomas Mark; Jia, Quanxi; Mueller, Alexander H; Luo, Hongmei

    2013-04-30

    A polymer-assisted deposition process for deposition of epitaxial cubic metal nitride films and the like is presented. The process includes solutions of one or more metal precursor and soluble polymers having binding properties for the one or more metal precursor. After a coating operation, the resultant coating is heated at high temperatures under a suitable atmosphere to yield metal nitride films and the like. Such films can be used as templates for the development of high quality cubic GaN based electronic devices.

  10. Structural and Optical Investigations of GaN-Si Interface for a Heterojunction Solar Cell

    SciTech Connect (OSTI)

    Williams, Joshua J.; Jeffries, April M.; Bertoni, Mariana I.; Williamson, Todd L.; Bowden, Stuart G.; Honsberg, Christiana B.

    2014-06-08

    In recent years the development of heterojunction silicon based solar cells has gained much attention, lea largely by the efforts of Panasonic’s HIT cell. The success of the HIT cell prompts the scientific exploration of other thin film layers, besides the industrially accepted amorphous silicon. In this paper we report upon the use of gallium nitride, grown by MBE at “low temperatures” (~200°C), on silicon wafers as one possible candidate for making a heterojunction solar cell; the first approximation of band alignments between GaN and Si; and the material quality as determined by X-ray diffraction.

  11. Towards Fully Integrated High Temperature Wireless Sensors Using GaN-based HEMT Devices

    SciTech Connect (OSTI)

    Kuruganti, Phani Teja [ORNL; Islam, Syed K [ORNL; Huque, Mohammad A [ORNL

    2008-01-01

    Wireless sensors which are capable of working at extreme environments can significantly improve the efficiency and performance of industrial processes by facilitating better control systems. GaN, a widely researched wide bandgap material, has the potential to be used both as a sensing material and to fabricate control electronics, making it a prime candidate for high temperature integrated wireless sensor fabrication. In this paper we are presenting an experimental study on AlGaN/GaN HEMT's performance at higher temperature (up to 300 C). From test results, DC and microwave parameters at different temperatures were extracted.

  12. Report on the 2014 Major Airports Survey by Andrew McCrindell and Alicia Tuppack, Major Airport Services

    E-Print Network [OSTI]

    Greenslade, Diana

    common concerns with untimely forecasts: insufficient fuel, lack of alternate option, safety compromised operators such as the Royal Flying Doctor Service (RFDS), and general aviation operators including outside of the 5nm TAF area. Only 24% of respondents used the Bureau aviation knowledge centre. Accuracy

  13. Tunnel-injection quantum dot deep-ultraviolet light-emitting diodes with polarization-induced doping in III-nitride heterostructures

    SciTech Connect (OSTI)

    Verma, Jai Islam, S. M.; Protasenko, Vladimir; Kumar Kandaswamy, Prem; Xing, Huili; Jena, Debdeep

    2014-01-13

    Efficient semiconductor optical emitters in the deep-ultraviolet spectral window are encountering some of the most deep rooted problems of semiconductor physics. In III-Nitride heterostructures, obtaining short-wavelength photon emission requires the use of wide bandgap high Al composition AlGaN active regions. High conductivity electron (n-) and hole (p-) injection layers of even higher bandgaps are necessary for electrical carrier injection. This approach requires the activation of very deep dopants in very wide bandgap semiconductors, which is a difficult task. In this work, an approach is proposed and experimentally demonstrated to counter the challenges. The active region of the heterostructure light emitting diode uses ultrasmall epitaxially grown GaN quantum dots. Remarkably, the optical emission energy from GaN is pushed from 365?nm (3.4?eV, the bulk bandgap) to below 240?nm (>5.2?eV) because of extreme quantum confinement in the dots. This is possible because of the peculiar bandstructure and band alignments in the GaN/AlN system. This active region design crucially enables two further innovations for efficient carrier injection: Tunnel injection of carriers and polarization-induced p-type doping. The combination of these three advances results in major boosts in electroluminescence in deep-ultraviolet light emitting diodes and lays the groundwork for electrically pumped short-wavelength lasers.

  14. Remarkably reduced efficiency droop by using staircase thin InGaN quantum barriers in InGaN based blue light emitting diodes

    SciTech Connect (OSTI)

    Zhou, Kun; Ikeda, Masao, E-mail: mikeda2013@sinano.ac.cn, E-mail: jpliu2010@sinano.ac.cn; Liu, Jianping, E-mail: mikeda2013@sinano.ac.cn, E-mail: jpliu2010@sinano.ac.cn; Zhang, Shuming; Li, Deyao; Zhang, Liqun; Yang, Hui [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou (China); Key Laboratory of Nanodevices and Applications, Chinese Academy of Sciences, Suzhou (China); Cai, Jin; Wang, Hui; Wang, H. B. [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou (China); Key Laboratory of Nanodevices and Applications, Chinese Academy of Sciences, Suzhou (China); Suzhou Nanojoin Photonics Co., Ltd., Suzhou (China)

    2014-10-27

    The efficiency droop of InGaN/GaN(InGaN) multiple quantum well (MQW) light emitting diodes (LEDs) with thin quantum barriers (QB) is studied. With thin GaN QB (3?nm–6?nm thickness), the efficiency droop is not improved, which indicates that hole transport cannot be significantly enhanced by the thin GaN QBs. On the contrary, the efficiency droop was remarkably reduced by using a InGaN staircase QB (InGaN SC-QB) MQWs structure where InGaN SC-QBs lower the transport energy barrier of holes. The efficiency droop ratio was as low as 3.3% up to 200?A/cm{sup 2} for the InGaN SC-QB LED. By using monitoring QW with longer wavelength we observe a much uniform carrier distribution in the InGaN SC-QB LEDs, which reveals the mechanism of improvement in the efficiency droop.

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

    SciTech Connect (OSTI)

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

    2013-06-15

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

  16. Sacrificial template method of fabricating a nanotube

    DOE Patents [OSTI]

    Yang, Peidong (Berkeley, CA); He, Rongrui (Berkeley, CA); Goldberger, Joshua (Berkeley, CA); Fan, Rong (El Cerrito, CA); Wu, Yi-Ying (Albany, CA); Li, Deyu (Albany, CA); Majumdar, Arun (Orinda, CA)

    2007-05-01

    Methods of fabricating uniform nanotubes are described in which nanotubes were synthesized as sheaths over nanowire templates, such as using a chemical vapor deposition process. For example, single-crystalline zinc oxide (ZnO) nanowires are utilized as templates over which gallium nitride (GaN) is epitaxially grown. The ZnO templates are then removed, such as by thermal reduction and evaporation. The completed single-crystalline GaN nanotubes preferably have inner diameters ranging from 30 nm to 200 nm, and wall thicknesses between 5 and 50 nm. Transmission electron microscopy studies show that the resultant nanotubes are single-crystalline with a wurtzite structure, and are oriented along the <001> direction. The present invention exemplifies single-crystalline nanotubes of materials with a non-layered crystal structure. Similar "epitaxial-casting" approaches could be used to produce arrays and single-crystalline nanotubes of other solid materials and semiconductors. Furthermore, the fabrication of multi-sheath nanotubes are described as well as nanotubes having multiple longitudinal segments.

  17. Combined TPRx, in situ GISAXS and GIXAS studies of model semiconductor-supported platinum catalysts in the hydrogenation of ethane.

    SciTech Connect (OSTI)

    Wyrzgol, S. A.; Schafer, S.; Lee, S.; Lee, B.; Di Vece, M.; Li, X.; Seifert, S.; Winans, R. E.; Stutzmann, M.; Lercher, J. A.; Vajda, S.; Technische Univ. Munchen; Yale Univ.

    2010-01-01

    The preparation, characterization and catalytic reactivity of a GaN supported Pt catalyst in the hydrogenation of ethene are presented in this feature article, highlighting the use of in situ characterization of the material properties during sample handling and catalysis by combining temperature programmed reaction with in situ grazing incidence small-angle X-ray scattering and X-ray absorption spectroscopy. The catalysts are found to be sintering resistant at elevated temperatures as well as during reduction and hydrogenation reactions. In contrast to Pt particles of approximately 7 nm diameter, smaller particles of 1.8 nm in size are found to dynamically adapt their shape and oxidation state to the changes in the reaction environment. These smaller Pt particles also showed an initial deactivation in ethene hydrogenation, which is paralleled by the change in the particle shape. The subtle temperature-dependent X-ray absorbance of the 1.8 nm sized Pt particles indicates that subtle variations in the electronic structure induced by the state of reduction by electron tunnelling over the Schottky barrier between the Pt particles and the GaN support can be monitored.

  18. Depth-resolved confocal micro-Raman spectroscopy for characterizing GaN-based light emitting diode structures

    SciTech Connect (OSTI)

    Chen, Wei-Liang; Lee, Yu-Yang; Chang, Yu-Ming, E-mail: ymchang@ntu.edu.tw [Center for Condensed Matter Sciences, National Taiwan University, 10617 Taipei, Taiwan (China)] [Center for Condensed Matter Sciences, National Taiwan University, 10617 Taipei, Taiwan (China); Chang, Chiao-Yun; Huang, Huei-Min; Lu, Tien-Chang [Department of Photonics, National Chiao Tung University, 30010 Hsinchu, Taiwan (China)] [Department of Photonics, National Chiao Tung University, 30010 Hsinchu, Taiwan (China)

    2013-11-15

    In this work, we demonstrate that depth-resolved confocal micro-Raman spectroscopy can be used to characterize the active layer of GaN-based LEDs. By taking the depth compression effect due to refraction index mismatch into account, the axial profiles of Raman peak intensities from the GaN capping layer toward the sapphire substrate can correctly match the LED structural dimension and allow the identification of unique Raman feature originated from the 0.3 ?m thick active layer of the studied LED. The strain variation in different sample depths can also be quantified by measuring the Raman shift of GaN A{sub 1}(LO) and E{sub 2}(high) phonon peaks. The capability of identifying the phonon structure of buried LED active layer and depth-resolving the strain distribution of LED structure makes this technique a potential optical and remote tool for in operando investigation of the electronic and structural properties of nitride-based LEDs.

  19. P-type gallium nitride

    DOE Patents [OSTI]

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

    1997-01-01

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

  20. Comparative study of polar and semipolar (112?2) InGaN layers grown by metalorganic vapour phase epitaxy

    SciTech Connect (OSTI)

    Dinh, Duc V. E-mail: peter.parbrook@tyndall.ie; Zubialevich, V. Z.; Oehler, F.; Kappers, M. J.; Humphreys, C. J.; Alam, S. N.; Parbrook, P. J. E-mail: peter.parbrook@tyndall.ie; Caliebe, M.; Scholtz, F.

    2014-10-21

    InGaN layers were grown simultaneously on (112?2) GaN and (0001) GaN templates by metalorganic vapour phase epitaxy. At higher growth temperature (?750°C), the indium content (<15%) of the (112?2) and (0001) InGaN layers was similar. However, for temperatures less than 750°C, the indium content of the (112?2) InGaN layers (15%–26%) were generally lower than those with (0001) orientation (15%–32%). The compositional deviation was attributed to the different strain relaxations between the (112?2) and (0001) InGaN layers. Room temperature photoluminescence measurements of the (112?2) InGaN layers showed an emission wavelength that shifts gradually from 380 nm to 580 nm with decreasing growth temperature (or increasing indium composition). The peak emission wavelength of the (112?2) InGaN layers with an indium content of more than 10% blue-shifted a constant value of ?(50–60) nm when using higher excitation power densities. This blue-shift was attributed to band filling effects in the layers.