National Library of Energy BETA

Sample records for bulk gallium nitride

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

    Broader source: Energy.gov [DOE]

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

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

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

    diodes (LEDs) on low-defect bulk gallium nitride (GaN) substrates. Peak internal quantum efficiency (IQE) values of greater than 80% are achieved over a wide wavelength range...

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

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

    High-Quality, Low- Cost Bulk Gallium Nitride Substrates Electrochemical Solution Growth: A Scalable Semiconductor Manufacturing Process The ever-growing demand in the past decade for more energy effcient solid-state lighting and electrical power conversion is leading to a higher demand for wide bandgap semiconductor-based devices, such as gallium nitride (GaN), over traditional silicon (Si)-based devices. High cost and limited availability, how- ever, have hindered the adoption of GaN substrates

  4. High-Quality, Low-Cost Bulk Gallium Nitride Substrates | Department of

    Office of Environmental Management (EM)

    Energy High-Quality, Low-Cost Bulk Gallium Nitride Substrates High-Quality, Low-Cost Bulk Gallium Nitride Substrates MEMC Electronic Materials, Inc. - St. Peters, MO Efficient manufacturing of gallium nitride (GaN) could reduce the cost of and improve the output for light-emitting diodes, solid-state lighting, laser displays, and other power electronics. Use of GaN-a semi-conductor material-holds the potential to reduce lighting energy use by 75%, electric drive motor energy use for consumer

  5. High Quality, Low Cost Bulk Gallium Nitride Substrates Grown by the Electrochemical Solution Growth Method

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

    Seacrist, Senior Fellow - Emerging Technologies R&D, SunEdison Semiconductor (formerly MEMC) U.S. DOE Advanced Manufacturing Office Program Review Meeting Washington, D.C. May 28-29, 2015 This presentation does not contain any proprietary, confidential, or otherwise restricted information. Project Objective  Develop electrochemical solution growth (ESG) of gallium nitride (GaN) into a technology capable of producing large area bulk GaN substrates  Bulk GaN enables homoepitaxial growth

  6. Gallium nitride nanotube lasers

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

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

    2015-01-01

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

  7. 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.

  8. P-type gallium nitride

    DOE Patents [OSTI]

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

    1997-08-12

    Several methods have been found to make p-type gallium nitride. P-type gallium nitride has long been sought for electronic devices. N-type gallium nitride is readily available. Discovery of p-type gallium nitride and the methods for making it will enable its use in ultraviolet and blue light-emitting diodes and lasers. pGaN will further enable blue photocathode elements to be made. Molecular beam epitaxy on substrates held at the proper temperatures, assisted by a nitrogen beam of the proper energy produced several types of p-type GaN with hole concentrations of about 5{times}10{sup 11} /cm{sup 3} and hole mobilities of about 500 cm{sup 2} /V-sec, measured at 250 K. P-type GaN can be formed of unintentionally-doped material or can be doped with magnesium by diffusion, ion implantation, or co-evaporation. When applicable, the nitrogen can be substituted with other group III elements such as Al. 9 figs.

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

    Broader source: Energy.gov [DOE]

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

  10. 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.

  11. 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.

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

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

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

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

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

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

  14. Smooth cubic commensurate oxides on gallium nitride

    SciTech Connect (OSTI)

    Paisley, Elizabeth A.; Gaddy, Benjamin E.; LeBeau, James M.; Shelton, Christopher T.; Losego, Mark D.; Mita, Seiji; Collazo, Ramn; Sitar, Zlatko; Irving, Douglas L.; Maria, Jon-Paul; Biegalski, Michael D.; Christen, Hans M.

    2014-02-14

    Smooth, commensurate alloys of ?111?-oriented Mg{sub 0.52}Ca{sub 0.48}O (MCO) thin films are demonstrated on Ga-polar, c+ [0001]-oriented GaN by surfactant-assisted molecular beam epitaxy and pulsed laser deposition. These are unique examples of coherent cubic oxide|nitride interfaces with structural and morphological perfection. Metal-insulator-semiconductor capacitor structures were fabricated on n-type GaN. A comparison of leakage current density for conventional and surfactant-assisted growth reveals a nearly 100 reduction in leakage current density for the surfactant-assisted samples. HAADF-STEM images of the MCO|GaN interface show commensurate alignment of atomic planes with minimal defects due to lattice mismatch. STEM and DFT calculations show that GaN c/2 steps create incoherent boundaries in MCO over layers which manifest as two in-plane rotations and determine consequently the density of structural defects in otherwise coherent MCO. This new understanding of interfacial steps between HCP and FCC crystals identifies the steps needed to create globally defect-free heterostructures.

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

    SciTech Connect (OSTI)

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

    2012-07-27

    Highlights: Black-Right-Pointing-Pointer Gallium nitride based sensors show promising characteristics to monitor cellular parameters. Black-Right-Pointing-Pointer Cell growth experiments reveal excellent biocompatibiltiy of the host GaN material. Black-Right-Pointing-Pointer We present a biofunctionality assay using ionizing radiation. Black-Right-Pointing-Pointer DNA repair is utilized to evaluate material induced alterations in the cellular behavior. Black-Right-Pointing-Pointer GaN shows no bio-functional influence on the cellular environment. -- Abstract: There is an increasing interest in the integration of hybrid bio-semiconductor systems for the non-invasive evaluation of physiological parameters. High quality gallium nitride and its alloys show promising characteristics to monitor cellular parameters. Nevertheless, such applications not only request appropriate sensing capabilities but also the biocompatibility and especially the biofunctionality of materials. Here we show extensive biocompatibility studies of gallium nitride and, for the first time, a biofunctionality assay using ionizing radiation. Analytical sensor devices are used in medical settings, as well as for cell- and tissue engineering. Within these fields, semiconductor devices have increasingly been applied for online biosensing on a cellular and tissue level. Integration of advanced materials such as gallium nitride into these systems has the potential to increase the range of applicability for a multitude of test devices and greatly enhance sensitivity and functionality. However, for such applications it is necessary to optimize cell-surface interactions and to verify the biocompatibility of the semiconductor. In this work, we present studies of mouse fibroblast cell activity grown on gallium nitride surfaces after applying external noxa. Cell-semiconductor hybrids were irradiated with X-rays at air kerma doses up to 250 mGy and the DNA repair dynamics, cell proliferation, and cell growth dynamics of adherent cells were compared to control samples. The impact of ionizing radiation on DNA, along with the associated cellular repair mechanisms, is well characterized and serves as a reference tool for evaluation of substrate effects. The results indicate that gallium nitride does not require specific surface treatments to ensure biocompatibility and suggest that cell signaling is not affected by micro-environmental alterations arising from gallium nitride-cell interactions. The observation that gallium nitride provides no bio-functional influence on the cellular environment confirms that this material is well suited for future biosensing applications without the need for additional chemical surface modification.

  16. 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.

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

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

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

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

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

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

  19. Process for growing epitaxial gallium nitride and composite wafers

    DOE Patents [OSTI]

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

    2003-05-13

    A novel growth procedure to grow epitaxial Group III metal nitride thin films on lattice-mismatched substrates is proposed. Demonstrated are the quality improvement of epitaxial GaN layers using a pure metallic Ga buffer layer on c-plane sapphire substrate. X-ray rocking curve results indicate that the layers had excellent structural properties. The electron Hall mobility increases to an outstandingly high value of .mu.>400 cm.sup.2 /Vs for an electron background concentration of 4.times.10.sup.17 cm.sup.-3.

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

    SciTech Connect (OSTI)

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

    2014-06-30

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

  1. Method of synthesizing bulk transition metal carbide, nitride and phosphide catalysts

    DOE Patents [OSTI]

    Choi, Jae Soon; Armstrong, Beth L; Schwartz, Viviane

    2015-04-21

    A method for synthesizing catalyst beads of bulk transmission metal carbides, nitrides and phosphides is provided. The method includes providing an aqueous suspension of transition metal oxide particles in a gel forming base, dropping the suspension into an aqueous solution to form a gel bead matrix, heating the bead to remove the binder, and carburizing, nitriding or phosphiding the bead to form a transition metal carbide, nitride, or phosphide catalyst bead. The method can be tuned for control of porosity, mechanical strength, and dopant content of the beads. The produced catalyst beads are catalytically active, mechanically robust, and suitable for packed-bed reactor applications. The produced catalyst beads are suitable for biomass conversion, petrochemistry, petroleum refining, electrocatalysis, and other applications.

  2. Silicon surface and bulk defect passivation by low temperature PECVD oxides and nitrides

    SciTech Connect (OSTI)

    Chen, Z.; Rohatgi, A.; Ruby, D.

    1995-01-01

    The effectiveness of PECVD passivation of surface and bulk defects in Si, as well as phosphorous diffused emitters, Is investigated and quantified. Significant hydrogen incorporation coupled with high positive charge density in the PECVD SiN layer is found to play an important role in bulk and surface passivation. It is shown that photo-assisted anneal in a forming gas ambient after PECVD depositions significantly improves the passivation of emitter and bulk defects. PECVD passivation of phosphorous doped emitters and boron doped bare Si surfaces is found to be a strong function of doping concentration. Surface recombination velocity of less than 200 cm/s for 0.2 Ohm-cm and less than 1 cm/s for high resistivity substrates ({approximately} Ohm-cm) were achieved. PECVD passivation improved bulk lifetime in the range of 30% to 70% in multicrystalline Si materials. However, the degree of the passivation was found to be highly material specific. Depending upon the passivation scheme, emitter saturation current density (J{sub oe}) can be reduced by a factor of 3 to 9. Finally, the stability of PECVD oxide/nitride passivation under prolonged UV exposure is established.

  3. 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.

  4. Superconducting structure with layers of niobium nitride and aluminum nitride

    DOE Patents [OSTI]

    Murduck, J.M.; Lepetre, Y.J.; Schuller, I.K.; Ketterson, J.B.

    1989-07-04

    A superconducting structure is formed by depositing alternate layers of aluminum nitride and niobium nitride on a substrate. Deposition methods include dc magnetron reactive sputtering, rf magnetron reactive sputtering, thin-film diffusion, chemical vapor deposition, and ion-beam deposition. Structures have been built with layers of niobium nitride and aluminum nitride having thicknesses in a range of 20 to 350 Angstroms. Best results have been achieved with films of niobium nitride deposited to a thickness of approximately 70 Angstroms and aluminum nitride deposited to a thickness of approximately 20 Angstroms. Such films of niobium nitride separated by a single layer of aluminum nitride are useful in forming Josephson junctions. Structures of 30 or more alternating layers of niobium nitride and aluminum nitride are useful when deposited on fixed substrates or flexible strips to form bulk superconductors for carrying electric current. They are also adaptable as voltage-controlled microwave energy sources. 8 figs.

  5. Superconducting structure with layers of niobium nitride and aluminum nitride

    DOE Patents [OSTI]

    Murduck, James M. (Lisle, IL); Lepetre, Yves J. (Lauris, FR); Schuller, Ivan K. (Woodridge, IL); Ketterson, John B. (Evanston, IL)

    1989-01-01

    A superconducting structure is formed by depositing alternate layers of aluminum nitride and niobium nitride on a substrate. Deposition methods include dc magnetron reactive sputtering, rf magnetron reactive sputtering, thin-film diffusion, chemical vapor deposition, and ion-beam deposition. Structures have been built with layers of niobium nitride and aluminum nitride having thicknesses in a range of 20 to 350 Angstroms. Best results have been achieved with films of niobium nitride deposited to a thickness of approximately 70 Angstroms and aluminum nitride deposited to a thickness of approximately 20 Angstroms. Such films of niobium nitride separated by a single layer of aluminum nitride are useful in forming Josephson junctions. Structures of 30 or more alternating layers of niobium nitride and aluminum nitride are useful when deposited on fixed substrates or flexible strips to form bulk superconductors for carrying electric current. They are also adaptable as voltage-controlled microwave energy sources.

  6. Growth process for gallium nitride porous nanorods

    DOE Patents [OSTI]

    Wildeson, Isaac Harshman; Sands, Timothy David

    2015-03-24

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

  7. 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.

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

    DOE Patents [OSTI]

    Kisielowski, Christian K. (Peidmont, CA); Rubin, Michael (Berkeley, CA)

    2000-01-01

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

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

    DOE Patents [OSTI]

    Kisielowski, Christian K. (Piedmont, CA); Rubin, Michael (Berkeley, CA)

    2002-01-01

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

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

    DOE Patents [OSTI]

    Armitage, Robert D.; Weber, Eicke R.

    2005-08-16

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

  11. Preparing titanium nitride powder

    DOE Patents [OSTI]

    Bamberger, Carlos E. (Oak Ridge, TN)

    1989-01-01

    A process for making titanium nitride powder by reaction of titanium phosphates with sodium cyanide.

  12. The Hardest Superconducting Metal Nitride

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

    Wang, Shanmin; Antonio, Daniel; Yu, Xiaohui; Zhang, Jianzhong; Cornelius, Andrew L.; He, Duanwei; Zhao, Yusheng

    2015-09-03

    Transition–metal (TM) nitrides are a class of compounds with a wide range of properties and applications. Hard superconducting nitrides are of particular interest for electronic applications under working conditions such as coating and high stress (e.g., electromechanical systems). However, most of the known TM nitrides crystallize in the rock–salt structure, a structure that is unfavorable to resist shear strain, and they exhibit relatively low indentation hardness, typically in the range of 10–20 GPa. Here, we report high–pressure synthesis of hexagonal δ–MoN and cubic γ–MoN through an ion–exchange reaction at 3.5 GPa. The final products are in the bulk form withmore » crystallite sizes of 50 – 80 μm. Based on indentation testing on single crystals, hexagonal δ–MoN exhibits excellent hardness of ~30 GPa, which is 30% higher than cubic γ–MoN (~23 GPa) and is so far the hardest among the known metal nitrides. The hardness enhancement in hexagonal phase is attributed to extended covalently bonded Mo–N network than that in cubic phase. The measured superconducting transition temperatures for δ–MoN and cubic γ–MoN are 13.8 and 5.5 K, respectively, in good agreement with previous measurements.« less

  13. The Hardest Superconducting Metal Nitride

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

    Wang, Shanmin; Antonio, Daniel; Yu, Xiaohui; Zhang, Jianzhong; Cornelius, Andrew L.; He, Duanwei; Zhao, Yusheng

    2015-09-03

    Transitionmetal (TM) nitrides are a class of compounds with a wide range of properties and applications. Hard superconducting nitrides are of particular interest for electronic applications under working conditions such as coating and high stress (e.g., electromechanical systems). However, most of the known TM nitrides crystallize in the rocksalt structure, a structure that is unfavorable to resist shear strain, and they exhibit relatively low indentation hardness, typically in the range of 1020 GPa. Here, we report highpressure synthesis of hexagonal ?MoN and cubic ?MoN through an ionexchange reaction at 3.5 GPa. The final products are in the bulk form withmorecrystallite sizes of 50 80 ?m. Based on indentation testing on single crystals, hexagonal ?MoN exhibits excellent hardness of ~30 GPa, which is 30% higher than cubic ?MoN (~23 GPa) and is so far the hardest among the known metal nitrides. The hardness enhancement in hexagonal phase is attributed to extended covalently bonded MoN network than that in cubic phase. The measured superconducting transition temperatures for ?MoN and cubic ?MoN are 13.8 and 5.5 K, respectively, in good agreement with previous measurements.less

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  19. Nitrided Metallic Bipolar Plates

    Broader source: Energy.gov [DOE]

    This presentation, which focuses on nitrided metallic bipolar plates, was given by M. P. Brady of ORNL at a February 2007 meeting on new fuel cell projects.

  20. Methods of forming boron nitride

    DOE Patents [OSTI]

    Trowbridge, Tammy L; Wertsching, Alan K; Pinhero, Patrick J; Crandall, David L

    2015-03-03

    A method of forming a boron nitride. The method comprises contacting a metal article with a monomeric boron-nitrogen compound and converting the monomeric boron-nitrogen compound to a boron nitride. The boron nitride is formed on the same or a different metal article. The monomeric boron-nitrogen compound is borazine, cycloborazane, trimethylcycloborazane, polyborazylene, B-vinylborazine, poly(B-vinylborazine), or combinations thereof. The monomeric boron-nitrogen compound is polymerized to form the boron nitride by exposure to a temperature greater than approximately 100.degree. C. The boron nitride is amorphous boron nitride, hexagonal boron nitride, rhombohedral boron nitride, turbostratic boron nitride, wurzite boron nitride, combinations thereof, or boron nitride and carbon. A method of conditioning a ballistic weapon and a metal article coated with the monomeric boron-nitrogen compound are also disclosed.

  1. Copper Indium Gallium Diselenide | Department of Energy

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

    Copper Indium Gallium Diselenide Copper Indium Gallium Diselenide Graphic showing the five layers of a CIGS PV cell: glass (or metal foil or plastics), Mo, CIGS, CdS, and transparent conductive oxide. DOE supports innovative research focused on overcoming the current technological and commercial barreirs for copper indium gallium diselenide [Cu(InxGa1-x)Se2], or CIGS, solar cells. A list of current projects, summary of the benefits, and discussion on the production and manufacturing of this

  2. Boron nitride nanotubes

    DOE Patents [OSTI]

    Smith, Michael W. (Newport News, VA); Jordan, Kevin (Newport News, VA); Park, Cheol (Yorktown, VA)

    2012-06-06

    Boron nitride nanotubes are prepared by a process which includes: (a) creating a source of boron vapor; (b) mixing the boron vapor with nitrogen gas so that a mixture of boron vapor and nitrogen gas is present at a nucleation site, which is a surface, the nitrogen gas being provided at a pressure elevated above atmospheric, e.g., from greater than about 2 atmospheres up to about 250 atmospheres; and (c) harvesting boron nitride nanotubes, which are formed at the nucleation site.

  3. Highly transparent ammonothermal bulk GaN substrates

    SciTech Connect (OSTI)

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

    2014-10-01

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

  4. Facile synthesis of efficient photocatalytic tantalum nitride nanoparticles

    SciTech Connect (OSTI)

    Wang, Zheng; Wang, Jiangting; Hou, Jungang; Huang, Kai; Jiao, Shuqiang; Zhu, Hongmin

    2012-11-15

    Graphical abstract: Tantalum nitride nanoparticles as a visible-light-driven photocatalyst prepared by a novel homogeneously chemical reduction of tantalum pentachloride using sodium in liquid ammonia and the morphologies, visible-light photocatalytic properties and stability of tantalum nitride nanoparticles were investigated. Highlights: ? Tantalum nitride nanoparticles have been prepared by a homogeneously chemical reduction. ? The crystal structure of tantalum nitride was determined by Rietveld refinement and XRD patterns. ? The Tantalum nitride nanoparticle size was in the range of 2050 nm. ? Much high photocatalytic activities of Ta{sub 3}N{sub 5} nanoparticles were obtained under visible-light irradiation. -- Abstract: Tantalum nitride nanoparticles, as visible-light photocatalysts were synthesized by a two-step homogeneously chemical reduction without any polymers and templates. The well-crystallized Ta{sub 3}N{sub 5} nanoparticles with a range of 2050 nm in size have been characterized by a number of techniques, such as XRD, XPS, SEM, TEM, BET and UVVis spectrum. Most importantly, the Ta{sub 3}N{sub 5} nanoparticles with good stability exhibited higher photooxidation activities in the water splitting and degradation of methylene blue under visible light irradiation than bulk Ta{sub 3}N{sub 5} particles and commercial P25 TiO{sub 2}, demonstrating that Ta{sub 3}N{sub 5} nanoparticle is a promising candidate as a visible-light photocatalyst.

  5. Generator for gallium-68 and compositions obtained therefrom

    DOE Patents [OSTI]

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

    1981-01-01

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

  6. 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.

  7. High-Efficiency Nitride-Based Photonic Crystal Light Sources

    Broader source: Energy.gov [DOE]

    The University of California Santa Barbara (UCSB) is maximizing the efficiency of a white LED by enhancing the external quantum efficiency using photonic crystals to extract light that would normally be confined in a conventional structure. Ultimate efficiency can only be achieved by looking at the internal structure of light. To do this, UCSB is focusing on maximizing the light extraction efficiency and total light output from light engines driven by Gallium Nitride (GaN)-based LEDs. The challenge is to engineer large overlap (interaction) between modes and photonic crystals. The project is focused on achieving high extraction efficiency in LEDs, controlled directionality of emitted light, integrated design of vertical device structure, and nanoscale patterning of lateral structure.

  8. Superplastic forging nitride ceramics

    DOE Patents [OSTI]

    Panda, Prakash C. (Ithaca, NY); Seydel, Edgar R. (Ithaca, NY); Raj, Rishi (Ithaca, NY)

    1988-03-22

    The invention relates to producing relatively flaw free silicon nitride ceramic shapes requiring little or no machining by superplastic forging This invention herein was made in part under Department of Energy Grant DE-AC01-84ER80167, creating certain rights in the United States Government. The invention was also made in part under New York State Science and Technology Grant SB1R 1985-10.

  9. III-Nitride Nanowires

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

    III-Nitride Nanowires - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Fuel Cycle Defense Waste Management Programs Advanced

  10. Electrochemical nitridation of metal surfaces

    DOE Patents [OSTI]

    Wang, Heli; Turner, John A.

    2015-06-30

    Electrochemical nitridation of metals and the produced metals are disclosed. An exemplary method of electrochemical nitridation of metals comprises providing an electrochemical solution at low temperature. The method also comprises providing a three-electrode potentiostat system. The method also comprises stabilizing the three-electrode potentiostat system at open circuit potential. The method also comprises applying a cathodic potential to a metal.

  11. Silicon nitride ceramic comprising samaria and ytterbia

    DOE Patents [OSTI]

    Yeckley, Russell L. (Oakham, MA)

    1996-01-01

    This invention relates to a sintered silicon nitride ceramic comprising samaria and ytterbia for enhanced toughness.

  12. Functionalized boron nitride nanotubes

    DOE Patents [OSTI]

    Sainsbury, Toby; Ikuno, Takashi; Zettl, Alexander K

    2014-04-22

    A plasma treatment has been used to modify the surface of BNNTs. In one example, the surface of the BNNT has been modified using ammonia plasma to include amine functional groups. Amine functionalization allows BNNTs to be soluble in chloroform, which had not been possible previously. Further functionalization of amine-functionalized BNNTs with thiol-terminated organic molecules has also been demonstrated. Gold nanoparticles have been self-assembled at the surface of both amine- and thiol-functionalized boron nitride Nanotubes (BNNTs) in solution. This approach constitutes a basis for the preparation of highly functionalized BNNTs and for their utilization as nanoscale templates for assembly and integration with other nanoscale materials.

  13. Synthesis and characterization of actinide nitrides

    SciTech Connect (OSTI)

    Jaques, Brian; Butt, Darryl P.; Marx, Brian M.; Hamdy, A.S.; Osterberg, Daniel; Balfour, Gordon

    2007-07-01

    A carbothermic reduction of the metal oxides in a hydrogen/nitrogen mixed gas stream prior to nitriding in a nitrogen gas stream was used to synthesize uranium nitride at 1500 deg. C, cerium nitride at 1400 deg. C, and dysprosium nitride at 1500 deg. C. Cerium nitride and dysprosium nitride were also synthesized via hydriding and nitriding the metal shavings at 900 deg. C and 1500 deg. C, respectively. Also, a novel ball-milling synthesis route was used to produce cerium nitride and dysprosium nitride from the metal shavings at room temperature. Dysprosium nitride was also produced by reacting the metal shavings in a high purity nitrogen gas stream at 1300 deg. C. All materials were characterized by phase analysis via X-ray diffraction. Only the high purity materials were further analyzed via chemical analysis to characterize the trace oxygen concentration. (authors)

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

    SciTech Connect (OSTI)

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

    2014-12-07

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

  15. Cordierite silicon nitride filters

    SciTech Connect (OSTI)

    Sawyer, J.; Buchan, B. ); Duiven, R.; Berger, M. ); Cleveland, J.; Ferri, J. )

    1992-02-01

    The objective of this project was to develop a silicon nitride based crossflow filter. This report summarizes the findings and results of the project. The project was phased with Phase I consisting of filter material development and crossflow filter design. Phase II involved filter manufacturing, filter testing under simulated conditions and reporting the results. In Phase I, Cordierite Silicon Nitride (CSN) was developed and tested for permeability and strength. Target values for each of these parameters were established early in the program. The values were met by the material development effort in Phase I. The crossflow filter design effort proceeded by developing a macroscopic design based on required surface area and estimated stresses. Then the thermal and pressure stresses were estimated using finite element analysis. In Phase II of this program, the filter manufacturing technique was developed, and the manufactured filters were tested. The technique developed involved press-bonding extruded tiles to form a filter, producing a monolithic filter after sintering. Filters manufactured using this technique were tested at Acurex and at the Westinghouse Science and Technology Center. The filters did not delaminate during testing and operated and high collection efficiency and good cleanability. Further development in areas of sintering and filter design is recommended.

  16. Hard carbon nitride and method for preparing same

    DOE Patents [OSTI]

    Haller, Eugene E. (Berkeley, CA); Cohen, Marvin L. (Berkeley, CA); Hansen, William L. (Walnut Creek, CA)

    1992-01-01

    Novel crystalline .alpha. (silicon nitride-like)-carbon nitride and .beta. (silicon nitride-like)-carbon nitride are formed by sputtering carbon in the presence of a nitrogen atmosphere onto a single crystal germanium or silicon, respectively, substrate.

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

    DOE Patents [OSTI]

    Smither, Robert K. (Hinsdale, IL); Knapp, Gordon S. (Cupertino, CA); Westbrook, Edwin M. (Chicago, IL); Forster, George A. (Westmont, IL)

    1990-01-01

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

  18. Superplastic forging nitride ceramics

    DOE Patents [OSTI]

    Panda, P.C.; Seydel, E.R.; Raj, R.

    1988-03-22

    A process is disclosed for preparing silicon nitride ceramic parts which are relatively flaw free and which need little or no machining, said process comprising the steps of: (a) preparing a starting powder by wet or dry mixing ingredients comprising by weight from about 70% to about 99% silicon nitride, from about 1% to about 30% of liquid phase forming additive and from 1% to about 7% free silicon; (b) cold pressing to obtain a preform of green density ranging from about 30% to about 75% of theoretical density; (c) sintering at atmospheric pressure in a nitrogen atmosphere at a temperature ranging from about 1,400 C to about 2,200 C to obtain a density which ranges from about 50% to about 100% of theoretical density and which is higher than said preform green density, and (d) press forging workpiece resulting from step (c) by isothermally uniaxially pressing said workpiece in an open die without initial contact between said workpiece and die wall perpendicular to the direction of pressing and so that pressed workpiece does not contact die wall perpendicular to the direction of pressing, to substantially final shape in a nitrogen atmosphere utilizing a temperature within the range of from about 1,400 C to essentially 1,750 C and strain rate within the range of about 10[sup [minus]7] to about 10[sup [minus]1] seconds[sup [minus]1], the temperature and strain rate being such that surface cracks do not occur, said pressing being carried out to obtain a shear deformation greater than 30% whereby superplastic forging is effected.

  19. Sandia Energy - III-Nitride Nanowires

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

    III-Nitride NanowiresTara Camacho-Lopez2015-03-25T21:58:18+00:00 III-Nitride Nanowires: Novel Emitters for Lighting Speaker: George Wang, EFRC Thrust Leader Date: September 14,...

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

    SciTech Connect (OSTI)

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

    1986-01-01

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

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

    SciTech Connect (OSTI)

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

    2009-07-15

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

  2. Rotary bulk solids divider

    DOE Patents [OSTI]

    Maronde, Carl P. (McMurray, PA); Killmeyer, Jr., Richard P. (Pittsburgh, PA)

    1992-01-01

    An apparatus for the disbursement of a bulk solid sample comprising, a gravity hopper having a top open end and a bottom discharge end, a feeder positioned beneath the gravity hopper so as to receive a bulk solid sample flowing from the bottom discharge end, and a conveyor receiving the bulk solid sample from the feeder and rotating on an axis that allows the bulk solid sample to disperse the sample to a collection station.

  3. Process for making transition metal nitride whiskers

    DOE Patents [OSTI]

    Bamberger, Carlos E. (Oak Ridge, TN)

    1989-01-01

    A process for making metal nitrides, particularly titanium nitride whiskers, using a cyanide salt as a reducing agent for a metal compound in the presence of an alkali metal oxide. Sodium cyanide, various titanates and titanium oxide mixed with sodium oxide react to provide titanium nitride whiskers that can be used as reinforcement to ceramic composites.

  4. Process for making transition metal nitride whiskers

    DOE Patents [OSTI]

    Bamberger, C.E.

    1988-04-12

    A process for making metal nitrides, particularly titanium nitride whiskers, using a cyanide salt as a reducing agent for a metal compound in the presence of an alkali metal oxide. Sodium cyanide, various titanates and titanium oxide mixed with sodium oxide react to provide titanium nitride whiskers that can be used as reinforcement to ceramic composites. 1 fig., 1 tab.

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

    DOE Patents [OSTI]

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

    1981-01-01

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

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

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

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

  7. Cavity optomechanics in gallium phosphide microdisks

    SciTech Connect (OSTI)

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

    2014-04-07

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

  8. Inhalation developmental toxicology studies: Gallium arsenide in mice and rats

    SciTech Connect (OSTI)

    Mast, T.J.; Greenspan, B.J.; Dill, J.A.; Stoney, K.H.; Evanoff, J.J.; Rommereim, R.L.

    1990-12-01

    Gallium arsenide is a crystalline compound used extensively in the semiconductor industry. Workers preparing solar cells and gallium arsenide ingots and wafers are potentially at risk from the inhalation of gallium arsenide dust. The potential for gallium arsenide to cause developmental toxicity was assessed in Sprague- Dawley rats and CD-1 (Swiss) mice exposed to 0, 10, 37, or 75 mg/m{sup 3} gallium arsenide, 6 h/day, 7 days/week. Each of the four treatment groups consisted of 10 virgin females (for comparison), and {approx}30 positively mated rats or {approx}24 positively mated mice. Mice were exposed on 4--17 days of gestation (dg), and rats on 4--19 dg. The day of plug or sperm detection was designated as 0 dg. Body weights were obtained throughout the study period, and uterine and fetal body weights were obtained at sacrifice (rats, 20 dg; mice, 18 dg). Implants were enumerated and their status recorded. Live fetuses were sexed and examined for gross, visceral, skeletal, and soft-tissue craniofacial defects. Gallium and arsenic concentrations were determined in the maternal blood and uterine contents of the rats (3/group) at 7, 14, and 20 dg. 37 refs., 11 figs., 30 tabs.

  9. Preparation of bulk superhard B-C-N nanocomposite compact

    DOE Patents [OSTI]

    Zhao, Yusheng; He, Duanwei

    2011-05-10

    Bulk, superhard, B--C--N nanocomposite compacts were prepared by ball milling a mixture of graphite and hexagonal boron nitride, encapsulating the ball-milled mixture at a pressure in a range of from about 15 GPa to about 25 GPa, and sintering the pressurized encapsulated ball-milled mixture at a temperature in a range of from about 1800-2500 K. The product bulk, superhard, nanocomposite compacts were well sintered compacts with nanocrystalline grains of at least one high-pressure phase of B--C--N surrounded by amorphous diamond-like carbon grain boundaries. The bulk compacts had a measured Vicker's hardness in a range of from about 41 GPa to about 68 GPa.

  10. Hanford ETR Bulk Vitrification System - Demonstration Bulk Vitrification

    Energy Savers [EERE]

    System (DBVS) Review Report | Department of Energy Hanford ETR Bulk Vitrification System - Demonstration Bulk Vitrification System (DBVS) Review Report Hanford ETR Bulk Vitrification System - Demonstration Bulk Vitrification System (DBVS) Review Report Full Document and Summary Versions are available for download PDF icon Hanford ETR Bulk Vitrification System - Demonstration Bulk Vitrification System (DBVS) Review Report PDF icon Summary - Demonstration Bulk Vitrification System (DBVS) for

  11. Memristor using a transition metal nitride insulator (Patent...

    Office of Scientific and Technical Information (OSTI)

    Patent: Memristor using a transition metal nitride insulator Citation Details In-Document Search Title: Memristor using a transition metal nitride insulator You are accessing a...

  12. Design and Implementation of Silicon Nitride Valves for Heavy...

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

    Implementation of Silicon Nitride Valves for Heavy Duty Diesel Engines Design and Implementation of Silicon Nitride Valves for Heavy Duty Diesel Engines Poster presentation at the...

  13. Epitaxial ternary nitride thin films prepared by a chemical solution...

    Office of Scientific and Technical Information (OSTI)

    Epitaxial ternary nitride thin films prepared by a chemical solution method Citation Details In-Document Search Title: Epitaxial ternary nitride thin films prepared by a chemical...

  14. Boron nitride ablation studies in arc jet facilities (Conference...

    Office of Scientific and Technical Information (OSTI)

    Boron nitride ablation studies in arc jet facilities Citation Details In-Document Search Title: Boron nitride ablation studies in arc jet facilities You are accessing a document...

  15. CX-010873: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

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

  16. Nanostructure, Chemistry and Crystallography of Iron Nitride...

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

    Nanostructure, Chemistry and Crystallography of Iron Nitride Magnetic Materials by Ultra-High-Resolution Electron Microscopy and Related Methods Nanostructure, Chemistry and ...

  17. Silicon nitride having a high tensile strength

    DOE Patents [OSTI]

    Pujari, Vimal K. (Northboro, MA); Tracey, Dennis M. (Medfield, MA); Foley, Michael R. (Oxford, MA); Paille, Norman I. (Oxford, MA); Pelletier, Paul J. (Sutton, MA); Sales, Lenny C. (Grafton, MA); Willkens, Craig A. (Worcester, MA); Yeckley, Russell L. (Latrobe, PA)

    1998-01-01

    A ceramic body comprising at least about 80 w/o silicon nitride and having a mean tensile strength of at least about 800 MPa.

  18. High density hexagonal boron nitride prepared by hot isostatic pressing in refractory metal containers

    DOE Patents [OSTI]

    Hoenig, Clarence L. (Livermore, CA)

    1992-01-01

    Boron nitride powder with less than or equal to the oxygen content of starting powder (down to 0.5% or less) is hot isostatically pressed in a refractory metal container to produce hexagonal boron nitride with a bulk density greater than 2.0 g/cc. The refractory metal container is formed of tantalum, niobium, tungsten, molybdenum or alloys thereof in the form of a canister or alternatively plasma sprayed or chemical vapor deposited onto a powder compact. Hot isostatic pressing at 1800.degree. C. and 30 KSI (206.8 MPa) argon pressure for four hours produces a bulk density of 2.21 g/cc. Complex shapes can be made.

  19. Large area bulk superconductors

    DOE Patents [OSTI]

    Miller, Dean J. (Darien, IL); Field, Michael B. (Jersey City, NJ)

    2002-01-01

    A bulk superconductor having a thickness of not less than about 100 microns is carried by a polycrystalline textured substrate having misorientation angles at the surface thereof not greater than about 15.degree.; the bulk superconductor may have a thickness of not less than about 100 microns and a surface area of not less than about 50 cm.sup.2. The textured substrate may have a thickness not less than about 10 microns and misorientation angles at the surface thereof not greater than about 15.degree.. Also disclosed is a process of manufacturing the bulk superconductor and the polycrystalline biaxially textured substrate material.

  20. Bulk superhard B-C-N nanocomposite compact and method for preparing thereof

    DOE Patents [OSTI]

    Zhao, Yusheng; He, Duanwei

    2004-07-06

    Bulk, superhard, B-C-N nanocomposite compact and method for preparing thereof. The bulk, superhard, nanocomposite compact is a well-sintered compact and includes nanocrystalline grains of at least one high-pressure phase of B-C-N surrounded by amorphous diamond-like carbon grain boundaries. The bulk compact has a Vicker's hardness of about 41-68 GPa. It is prepared by ball milling a mixture of graphite and hexagonal boron nitride, encapsulating the ball-milled mixture, and sintering the encapsulated ball-milled mixture at a pressure of about 5-25 GPa and at a temperature of about 1000-2500 K.

  1. Fiber Bulk Gaseous Carriers

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

    Don Baldwin, Director of Product Development FIBER BULK GASEOUS CARRIERS 26 February 2014, NREL, Golden, CO * Lightweight composite cylinders for the storage and transportation of gas under pressure ̵ Compressed natural gas ̵ Compressed hydrogen gas * Vehicle fuel cylinders ̵ Passenger cars ̵ Buses and ̵ Heavy-duty vehicles * Transport and storage cylinders ̵ Bulk hauling trailers and modules ̵ Ground storage systems HEXAGON COMPOSITES HIGH PRESSURE PRODUCTS * Figures with

  2. Gallium based low-interaction anions

    DOE Patents [OSTI]

    King, Wayne A. (Santa Fe, NM); Kubas, Gregory J. (Santa Fe, NM)

    2000-01-01

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

  3. Multifunctional bulk plasma source based on discharge with electron injection

    SciTech Connect (OSTI)

    Klimov, A. S.; Medovnik, A. V.; Tyunkov, A. V.; Savkin, K. P.; Shandrikov, M. V.; Vizir, A. V.

    2013-01-15

    A bulk plasma source, based on a high-current dc glow discharge with electron injection, is described. Electron injection and some special design features of the plasma arc emitter provide a plasma source with very long periods between maintenance down-times and a long overall lifetime. The source uses a sectioned sputter-electrode array with six individual sputter targets, each of which can be independently biased. This discharge assembly configuration provides multifunctional operation, including plasma generation from different gases (argon, nitrogen, oxygen, acetylene) and deposition of composite metal nitride and oxide coatings.

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

    DOE Patents [OSTI]

    Hogan, Stephen J. (Golden, CO)

    1986-01-01

    Disclosed is an improved process for manufacturing gallium arsenide semiconductor devices having as its components an n-type gallium arsenide substrate layer and a p-type gallium arsenide diffused layer. The improved process comprises forming a pure silver ohmic contact to both the diffused layer and the substrate layer, wherein the n-type layer comprises a substantially low doping carrier concentration.

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

    DOE Patents [OSTI]

    Hogan, S.J.

    1983-03-13

    Disclosed is an improved process for manufacturing gallium arsenide semiconductor devices having as its components a n-type gallium arsenide substrate layer and a p-type gallium arsenide diffused layer. The improved process comprises forming a pure silver ohmic contact to both the diffuse layer and the substrate layer wherein the n-type layer comprises a substantially low doping carrier concentration.

  6. Method of preparation of uranium nitride

    DOE Patents [OSTI]

    Kiplinger, Jaqueline Loetsch; Thomson, Robert Kenneth James

    2013-07-09

    Method for producing terminal uranium nitride complexes comprising providing a suitable starting material comprising uranium; oxidizing the starting material with a suitable oxidant to produce one or more uranium(IV)-azide complexes; and, sufficiently irradiating the uranium(IV)-azide complexes to produce the terminal uranium nitride complexes.

  7. Molten-Salt-Based Growth of Group III Nitrides

    DOE Patents [OSTI]

    Waldrip, Karen E. (Albuquerque, NM); Tsao, Jeffrey Y. (Albuquerque, NM); Kerley, Thomas M. (Albuquerque, NM)

    2008-10-14

    A method for growing Group III nitride materials using a molten halide salt as a solvent to solubilize the Group-III ions and nitride ions that react to form the Group III nitride material. The concentration of at least one of the nitride ion or Group III cation is determined by electrochemical generation of the ions.

  8. Hard carbon nitride and method for preparing same

    DOE Patents [OSTI]

    Haller, E.E.; Cohen, M.L.; Hansen, W.L.

    1992-05-05

    Novel crystalline [alpha](silicon nitride-like)-carbon nitride and [beta](silicon nitride-like)-carbon nitride are formed by sputtering carbon in the presence of a nitrogen atmosphere onto a single crystal germanium or silicon, respectively, substrate. 1 figure.

  9. Boron nitride ablation studies in arc jet facilities (Conference...

    Office of Scientific and Technical Information (OSTI)

    NITRIDES; NITROGEN COMPOUNDS; OPENINGS; PNICTIDES; SPACE VEHICLES 360205* -- Ceramics, Cermets, & Refractories-- Corrosion & Erosion; 320201 -- Energy Conservation,...

  10. First results from the Soviet-American Gallium Experiment

    SciTech Connect (OSTI)

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

    1990-01-01

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

  11. Photodetectors using III-V nitrides

    DOE Patents [OSTI]

    Moustakas, Theodore D.; Misra, Mira

    1997-01-01

    A photodetector using a III-V nitride and having predetermined electrical properties is disclosed. The photodetector includes a substrate with interdigitated electrodes formed on its surface. The substrate has a sapphire base layer, a buffer layer formed from a III-V nitride and a single crystal III-V nitride film. The three layers are formed by electron cyclotron resonance microwave plasma-assisted molecular beam epitaxy (ECR-assisted MBE). Use of the ECR-assisted MBE process allows control and predetermination of the electrical properties of the photodetector.

  12. Photodetectors using III-V nitrides

    DOE Patents [OSTI]

    Moustakas, T.D.; Misra, M.

    1997-10-14

    A photodetector using a III-V nitride and having predetermined electrical properties is disclosed. The photodetector includes a substrate with interdigitated electrodes formed on its surface. The substrate has a sapphire base layer, a buffer layer formed from a III-V nitride and a single crystal III-V nitride film. The three layers are formed by electron cyclotron resonance microwave plasma-assisted molecular beam epitaxy (ECR-assisted MBE). Use of the ECR-assisted MBE process allows control and predetermination of the electrical properties of the photodetector. 24 figs.

  13. Design of Integrated III-Nitride/Non-III-Nitride Tandem Photovoltaic Devices

    SciTech Connect (OSTI)

    Toledo, N. G.; Friedman, D.J.; Farrell, R. M.; Perl, E. E.; Lin, C. T.; Bowers, J. E.; Speck, J. S.; Mishra, U. K.

    2012-03-01

    The integration of III-nitride and non-III-nitride materials for tandem solar cell applications can improve the efficiency of the photovoltaic device due to the added power contributed by the III-nitride top cell to that of high-efficiency multi-junction non-III-nitride solar cells if the device components are properly designed and optimized. The proposed tandem solar cell is comprised of a III-nitride top cell bonded to a non-III-nitride, series-constrained, multi-junction subcell. The top cell is electrically isolated, but optically coupled to the underlying subcell. The use of a III-nitride top cell is potentially beneficial when the top junction of a stand-alone non-III-nitride subcell generates more photocurrent than the limiting current of the non-III-nitride subcell. Light producing this excess current can either be redirected to the III-nitride top cell through high energy photon absorption, redirected to the lower junctions through layer thickness optimization, or a combination of both, resulting in improved total efficiency. When the non-III-nitride cell's top junction is the limiting junction, the minimum power conversion efficiency that the III-nitride top cell must contribute should compensate for the spectrum filtered from the multi-junction subcell for this design to be useful. As the III-nitride absorption edge wavelength, {lambda}{sub N}, increases, the performance of the multi-junction subcell decreases due to spectral filtering. In the most common spectra of interest (AM1.5G, AM1.5 D, and AM0), the technology to grow InGaN cells with {lambda}{sub N}<520 nm is found to be sufficient for III-nitride top cell applications. The external quantum efficiency performance, however, of state-of-the-art InGaN solar cells still needs to be improved. The effects of surface/interface reflections are also presented. The management of these reflection issues determines the feasibility of the integrated III-nitride/non-III-nitride design to improve overall cell efficiency.

  14. Silicon nitride having a high tensile strength

    DOE Patents [OSTI]

    Pujari, V.K.; Tracey, D.M.; Foley, M.R.; Paille, N.I.; Pelletier, P.J.; Sales, L.C.; Willkens, C.A.; Yeckley, R.L.

    1998-06-02

    A ceramic body is disclosed comprising at least about 80 w/o silicon nitride and having a mean tensile strength of at least about 800 MPa. 4 figs.

  15. Method of nitriding refractory metal articles

    DOE Patents [OSTI]

    Tiegs, T.N.; Holcombe, C.E.; Dykes, N.L.; Omatete, O.O.; Young, A.C.

    1994-03-15

    A method of nitriding a refractory-nitride forming metal or metalloid articles and composite articles. A consolidated metal or metalloid article or composite is placed inside a microwave oven and nitrogen containing gas is introduced into the microwave oven. The metal or metalloid article or composite is heated to a temperature sufficient to react the metal or metalloid with the nitrogen by applying a microwave energy within the microwave oven. The metal or metalloid article or composite is maintained at that temperature for a period of time sufficient to convert the article of metal or metalloid or composite to an article or composite of refractory nitride. In addition, a method of applying a coating, such as a coating of an oxide, a carbide, or a carbo-nitride, to an article of metal or metalloid by microwave heating.

  16. Method of nitriding refractory metal articles

    DOE Patents [OSTI]

    Tiegs, Terry N. (Lenoir City, TN); Holcombe, Cressie E. (Knoxville, TN); Dykes, Norman L. (Oak Ridge, TN); Omatete, Ogbemi O. (Lagos, NG); Young, Albert C. (Flushing, NY)

    1994-01-01

    A method of nitriding a refractory-nitride forming metal or metalloid articles and composite articles. A consolidated metal or metalloid article or composite is placed inside a microwave oven and nitrogen containing gas is introduced into the microwave oven. The metal or metalloid article or composite is heated to a temperature sufficient to react the metal or metalloid with the nitrogen by applying a microwave energy within the microwave oven. The metal or metalloid article or composite is maintained at that temperature for a period of time sufficient to convert the article of metal or metalloid or composite to an article or composite of refractory nitride. In addition, a method of applying a coating, such as a coating of an oxide, a carbide, or a carbo-nitride, to an article of metal or metalloid by microwave heating.

  17. Low temperature route to uranium nitride

    DOE Patents [OSTI]

    Burrell, Anthony K. (Los Alamos, NM); Sattelberger, Alfred P. (Darien, IL); Yeamans, Charles (Berkeley, CA); Hartmann, Thomas (Idaho Falls, ID); Silva, G. W. Chinthaka (Las Vegas, NV); Cerefice, Gary (Henderson, NV); Czerwinski, Kenneth R. (Henderson, NV)

    2009-09-01

    A method of preparing an actinide nitride fuel for nuclear reactors is provided. The method comprises the steps of a) providing at least one actinide oxide and optionally zirconium oxide; b) mixing the oxide with a source of hydrogen fluoride for a period of time and at a temperature sufficient to convert the oxide to a fluoride salt; c) heating the fluoride salt to remove water; d) heating the fluoride salt in a nitrogen atmosphere for a period of time and at a temperature sufficient to convert the fluorides to nitrides; and e) heating the nitrides under vacuum and/or inert atmosphere for a period of time sufficient to convert the nitrides to mononitrides.

  18. Nitrided Metallic Bipolar Plates | Department of Energy

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

    on Oct. 25, 2006. PDF icon 4ornl.pdf More Documents & Publications Nitrided Metallic Bipolar Plates Mass Production Cost Estimation for Direct H2 PEM Fuel Cell Systems for...

  19. Self- and zinc diffusion in gallium antimonide

    SciTech Connect (OSTI)

    Nicols, Samuel Piers

    2002-03-26

    The technological age has in large part been driven by the applications of semiconductors, and most notably by silicon. Our lives have been thoroughly changed by devices using the broad range of semiconductor technology developed over the past forty years. Much of the technological development has its foundation in research carried out on the different semiconductors whose properties can be exploited to make transistors, lasers, and many other devices. While the technological focus has largely been on silicon, many other semiconductor systems have applications in industry and offer formidable academic challenges. Diffusion studies belong to the most basic studies in semiconductors, important from both an application as well as research standpoint. Diffusion processes govern the junctions formed for device applications. As the device dimensions are decreased and the dopant concentrations increased, keeping pace with Moore's Law, a deeper understanding of diffusion is necessary to establish and maintain the sharp dopant profiles engineered for optimal device performance. From an academic viewpoint, diffusion in semiconductors allows for the study of point defects. Very few techniques exist which allow for the extraction of as much information of their properties. This study focuses on diffusion in the semiconductor gallium antimonide (GaSb). As will become clear, this compound semiconductor proves to be a powerful one for investigating both self- and foreign atom diffusion. While the results have direct applications for work on GaSb devices, the results should also be taken in the broader context of III-V semiconductors. Results here can be compared and contrasted to results in systems such as GaAs and even GaN, indicating trends within this common group of semiconductors. The results also have direct importance for ternary and quaternary semiconductor systems used in devices such as high speed InP/GaAsSb/InP double heterojunction bipolar transistors (DHBT) [Dvorak, (2001)]. Many of the findings which will be reported here were previously published in three journal articles. Hartmut Bracht was the lead author on two articles on self-diffusion studies in GaSb [Bracht, (2001), (2000)], while this report's author was the lead author on Zn diffusion results [Nicols, (2001)]. Much of the information contained herein can be found in those articles, but a more detailed treatment is presented here.

  20. Band anticrossing in dilute nitrides

    SciTech Connect (OSTI)

    Shan, W.; Yu, K.M.; Walukiewicz, W.; Wu, J.; Ager III, J.W.; Haller, E.E.

    2003-12-23

    Alloying III-V compounds with small amounts of nitrogen leads to dramatic reduction of the fundamental band-gap energy in the resulting dilute nitride alloys. The effect originates from an anti-crossing interaction between the extended conduction-band states and localized N states. The interaction splits the conduction band into two nonparabolic subbands. The downward shift of the lower conduction subband edge is responsible for the N-induced reduction of the fundamental band-gap energy. The changes in the conduction band structure result in significant increase in electron effective mass and decrease in the electron mobility, and lead to a large enhance of the maximum doping level in GaInNAs doped with group VI donors. In addition, a striking asymmetry in the electrical activation of group IV and group VI donors can be attributed to mutual passivation process through formation of the nearest neighbor group-IV donor nitrogen pairs.

  1. The Nitrogen-Nitride Anode.

    SciTech Connect (OSTI)

    Delnick, Frank M.

    2014-10-01

    Nitrogen gas N 2 can be reduced to nitride N -3 in molten LiCl-KCl eutectic salt electrolyte. However, the direct oxidation of N -3 back to N 2 is kinetically slow and only occurs at high overvoltage. The overvoltage for N -3 oxidation can be eliminated by coordinating the N -3 with BN to form the dinitridoborate (BN 2 -3 ) anion which forms a 1-D conjugated linear inorganic polymer with -Li-N-B-N- repeating units. This polymer precipitates out of solution as Li 3 BN 2 which becomes a metallic conductor upon delithiation. Li 3 BN 2 is oxidized to Li + + N 2 + BN at about the N 2 /N -3 redox potential with very little overvoltage. In this report we evaluate the N 2 /N -3 redox couple as a battery anode for energy storage.

  2. Vibronic fine structure in high-resolution x-ray absorption spectra from ion-bombarded boron nitride nanotubes

    SciTech Connect (OSTI)

    Petravic, Mladen; Peter, Robert; Varasanec, Marijana; Li Luhua; Chen Ying; Cowie, Bruce C. C.

    2013-05-15

    The authors have applied high-resolution near-edge x-ray absorption fine structure measurements around the nitrogen K-edge to study the effects of ion-bombardment on near-surface properties of boron nitride nanotubes. A notable difference has been observed between surface sensitive partial electron yield (PEY) and bulk sensitive total electron yield (TEY) fine-structure measurements. The authors assign the PEY fine structure to the coupling of excited molecular vibrational modes to electronic transitions in NO molecules trapped just below the surface. Oxidation resistance of the boron nitride nanotubes is significantly reduced by low energy ion bombardment, as broken B-N bonds are replaced by N-O bonds involving oxygen present in the surface region. In contrast to the PEY spectra, the bulk sensitive TEY measurements on as-grown samples do not exhibit any fine structure while the ion-bombarded samples show a clear vibronic signature of molecular nitrogen.

  3. Method of manufacture of atomically thin boron nitride

    DOE Patents [OSTI]

    Zettl, Alexander K

    2013-08-06

    The present invention provides a method of fabricating at least one single layer hexagonal boron nitride (h-BN). In an exemplary embodiment, the method includes (1) suspending at least one multilayer boron nitride across a gap of a support structure and (2) performing a reactive ion etch upon the multilayer boron nitride to produce the single layer hexagonal boron nitride suspended across the gap of the support structure. The present invention also provides a method of fabricating single layer hexagonal boron nitride. In an exemplary embodiment, the method includes (1) providing multilayer boron nitride suspended across a gap of a support structure and (2) performing a reactive ion etch upon the multilayer boron nitride to produce the single layer hexagonal boron nitride suspended across the gap of the support structure.

  4. Local residual stress monitoring of aluminum nitride MEMS using...

    Office of Scientific and Technical Information (OSTI)

    Language: English Subject: 42 ENGINEERING aluminum nitride; microelectromechanical systems; Piezoelectric transducers; Raman scattering; stress measurement Word Cloud More Like ...

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

    Office of Scientific and Technical Information (OSTI)

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

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

    DOE Patents [OSTI]

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

    1998-08-08

    High quality thin films of copper-indium-gallium-diselenide useful in the production of solar cells are prepared by electrodepositing at least one of the constituent metals onto a glass/Mo substrate, followed by physical vapor deposition of copper and selenium or indium and selenium to adjust the final stoichiometry of the thin film to approximately Cu(In,Ga)Se.sub.2. Using an AC voltage of 1-100 KHz in combination with a DC voltage for electrodeposition improves the morphology and growth rate of the deposited thin film. An electrodeposition solution comprising at least in part an organic solvent may be used in conjunction with an increased cathodic potential to increase the gallium content of the electrodeposited thin film.

  7. Explosive bulk charge

    DOE Patents [OSTI]

    Miller, Jacob Lee

    2015-04-21

    An explosive bulk charge, including: a first contact surface configured to be selectively disposed substantially adjacent to a structure or material; a second end surface configured to selectively receive a detonator; and a curvilinear side surface joining the first contact surface and the second end surface. The first contact surface, the second end surface, and the curvilinear side surface form a bi-truncated hemispherical structure. The first contact surface, the second end surface, and the curvilinear side surface are formed from an explosive material. Optionally, the first contact surface and the second end surface each have a substantially circular shape. Optionally, the first contact surface and the second end surface consist of planar structures that are aligned substantially parallel or slightly tilted with respect to one another. The curvilinear side surface has one of a smooth curved geometry, an elliptical geometry, and a parabolic geometry.

  8. Creating bulk nanocrystalline metal.

    SciTech Connect (OSTI)

    Fredenburg, D. Anthony; Saldana, Christopher J.; Gill, David D.; Hall, Aaron Christopher; Roemer, Timothy John; Vogler, Tracy John; Yang, Pin

    2008-10-01

    Nanocrystalline and nanostructured materials offer unique microstructure-dependent properties that are superior to coarse-grained materials. These materials have been shown to have very high hardness, strength, and wear resistance. However, most current methods of producing nanostructured materials in weapons-relevant materials create powdered metal that must be consolidated into bulk form to be useful. Conventional consolidation methods are not appropriate due to the need to maintain the nanocrystalline structure. This research investigated new ways of creating nanocrystalline material, new methods of consolidating nanocrystalline material, and an analysis of these different methods of creation and consolidation to evaluate their applicability to mesoscale weapons applications where part features are often under 100 {micro}m wide and the material's microstructure must be very small to give homogeneous properties across the feature.

  9. Silicon nitride ceramic having high fatigue life and high toughness

    DOE Patents [OSTI]

    Yeckley, Russell L. (Oakham, MA)

    1996-01-01

    A sintered silicon nitride ceramic comprising between about 0.6 mol % and about 3.2 mol % rare earth as rare earth oxide, and between about 85 w/o and about 95 w/o beta silicon nitride grains, wherein at least about 20% of the beta silicon nitride grains have a thickness of greater than about 1 micron.

  10. 03.01.16 RH Nickel-Gallium - JCAP

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

    Research Introduction Why Solar Fuels? Goals & Objectives Thrusts Thrust 1 Thrust 2 Thrust 3 Thrust 4 Library Publications Research Highlights Videos Resources User Facilities Expert Team Benchmarking Database Device Simulation Tool XPS Spectral Database CO2 electrochemical reduction catalyzed by bimetallic materials at low overpotential Torelli, D. A., Francis, S.A. et al. Nickel-Gallium-Catalyzed Electrochemical Reduction of CO2 to Highly Reduced Products at Low Overpotentials. ACS

  11. The influence of random indium alloy fluctuations in indium gallium nitride quantum wells on the device behavior

    SciTech Connect (OSTI)

    Yang, Tsung-Jui; Wu, Yuh-Renn; Shivaraman, Ravi; Speck, James S.

    2014-09-21

    In this paper, we describe the influence of the intrinsic indium fluctuation in the InGaN quantum wells on the carrier transport, efficiency droop, and emission spectrum in GaN-based light emitting diodes (LEDs). Both real and randomly generated indium fluctuations were used in 3D simulations and compared to quantum wells with a uniform indium distribution. We found that without further hypothesis the simulations of electrical and optical properties in LEDs such as carrier transport, radiative and Auger recombination, and efficiency droop are greatly improved by considering natural nanoscale indium fluctuations.

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

    SciTech Connect (OSTI)

    STEVE SEDLOCK

    2012-04-04

    The design of power amplifiers in any semi-conductor process is not a trivia exercise and it is often encountered that the simulated solution is qualitatively different than the results obtained. Phenomena such as oscillation occurring either in-band or out of band and sometimes at subharmonic intervals, continuous spectrum noticed in some frequency bands, often referred to as chaos, and jumps and hysteresis effects can all be encountered and render a design useless. All of these problems might have been identified through a more rigorous approach to stability analysis. Designing for stability is probably the one area of amplifier design that receives the least amount of attention but incurs the most catastrophic of effects if it is not performed properly. Other parameters such as gain, power output, frequency response and even matching may suitable mitigation paths. But the lack of stability in an amplifier has no mitigating path. In addition to of loss of the design completely there are the increased production cycle costs, costs involved with investigating and resolving the problem and the costs involved with schedule slips or delays resulting from it. The Linville or Rollett stability criteria that many microwave engineers follow and rely exclusively on is not sufficient by itself to ensure a stable and robust design. It will be shown that the universal belief that unconditional stability is obtained through an analysis of the scattering matrix S to determine if 1 and |{Delta}{sub S}| < 1 is only part of the procedure and other tools must be used to validate the criteria. The research shown contributes to the state of the art by developing a more thorough stability design technique for designing amplifiers of any class, whether that be current mode or switch mode, than is currently undertaken with the goal of obtaining first pass design success.

  13. Anisotropic Hexagonal Boron Nitride Nanomaterials - Synthesis and Applications

    SciTech Connect (OSTI)

    Han,W.Q.

    2008-08-01

    Boron nitride (BN) is a synthetic binary compound located between III and V group elements in the Periodic Table. However, its properties, in terms of polymorphism and mechanical characteristics, are rather close to those of carbon compared with other III-V compounds, such as gallium nitride. BN crystallizes into a layered or a tetrahedrally linked structure, like those of graphite and diamond, respectively, depending on the conditions of its preparation, especially the pressure applied. Such correspondence between BN and carbon readily can be understood from their isoelectronic structures [1, 2]. On the other hand, in contrast to graphite, layered BN is transparent and is an insulator. This material has attracted great interest because, similar to carbon, it exists in various polymorphic forms exhibiting very different properties; however, these forms do not correspond strictly to those of carbon. Crystallographically, BN is classified into four polymorphic forms: Hexagonal BN (h-BN) (Figure 1(b)); rhombohedral BN (r-BN); cubic BN (c-BN); and wurtzite BN (w-BN). BN does not occur in nature. In 1842, Balmain [3] obtained BN as a reaction product between molten boric oxide and potassium cyanide under atmospheric pressure. Thereafter, many methods for its synthesis were reported. h-BN and r-BN are formed under ambient pressure. c-BN is synthesized from h-BN under high pressure at high temperature while w-BN is prepared from h-BN under high pressure at room temperature [1]. Each BN layer consists of stacks of hexagonal plate-like units of boron and nitrogen atoms linked by SP{sup 2} hybridized orbits and held together mainly by Van der Waals force (Fig 1(b)). The hexagonal polymorph has two-layered repeating units: AA'AA'... that differ from those in graphite: ABAB... (Figure 1(a)). Within the layers of h-BN there is coincidence between the same phases of the hexagons, although the boron atoms and nitrogen atoms are alternatively located along the c-axis. The rhombohedral system consists of three-layered units: ABCABC..., whose honeycomb layers are arranged in a shifted phase, like as those of graphite. Reflecting its weak interlayer bond, the h-BN can be cleaved easily along its layers, and hence, is widely used as a lubricant material. The material is stable up to a high temperature of 2300 C before decomposition sets in [2] does not fuse a nitrogen atmosphere of 1 atm, and thus, is applicable as a refractory material. Besides having such properties, similar to those of graphite, the material is transparent, and acts as a good electric insulator, especially at high temperatures (10{sup 6} {Omega}m at 1000 C) [1]. c-BN and w-BN are tetrahedrally linked BN. The former has a cubic sphalerite-type structure, and the latter has a hexagonal wurtzite-type structure. c-BN is the second hardest known material (the hardest is diamond), the so-called white diamond. It is used mainly for grinding and cutting industrial ferrous materials because it does not react with molten iron, nickel, and related alloys at high temperatures whereas diamond does [1]. It displays the second highest thermal conductivity (6-9 W/cm.deg) after diamond. This chapter focuses principally upon information about h-BN nanomaterials, mainly BN nanotubes (BNNTs), porous BN, mono- and few-layer-BN sheets. There are good reviews book chapters about c-BN in [1, 4-6].

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

    DOE Patents [OSTI]

    Marks, Tobin J.; Chen, You-Xian

    2000-01-01

    Salts of (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium are described. The (polyfluoroaryl)fluoroanions have the formula [ER'R"R'"F].sup..crclbar. wherein E is aluminum, gallium, or indium, wherein F is fluorine, and wherein R', R", and R'" is each a fluorinated phenyl, fluorinated biphenyl, or fluorinated polycyclic group.

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

    SciTech Connect (OSTI)

    Lenihan, K.L.

    1987-03-01

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

  16. Bulk Data Mover

    Energy Science and Technology Software Center (OSTI)

    2011-01-03

    Bulk Data Mover (BDM) is a high-level data transfer management tool. BDM handles the issue of large variance in file sizes and a big portion of small files by managing the file transfers with optimized transfer queue and concurrency management algorithms. For example, climate simulation data sets are characterized by large volume of files with extreme variance in file sizes. The BDN achieves high performance using a variety of techniques, including multi-thraded concurrent transfer connections,more » data channel caching, load balancing over multiple transfer servers, and storage i/o pre-fetching. Logging information from the BDM is collected and analyzed to study the effectiveness of the transfer management algorithms. The BDM can accept a request composed of multiple files or an entire directory. The request also contains the target site and directory where the replicated files will reside. If a directory is provided at the source, then the BDM will replicate the structure of the source directory at the target site. The BDM is capable of transferring multiple files concurrently as well as using parallel TCP streams. The optimal level of concurrency or parallel streams depends on the bandwidth capacity of the storage systems at both ends of the transfer as well as achievable bandwidth of the wide-area network. Hardware req.-PC, MAC, Multi-platform & Workstation; Software req.: Compile/version-Java 1.50_x or ablove; Type of files: source code, executable modules, installation instructions other, user guide; URL: http://sdm.lbl.gov/bdm/« less

  17. Photodetectors using III-V nitrides

    DOE Patents [OSTI]

    Moustakas, T.D.

    1998-12-08

    A bandpass photodetector using a III-V nitride and having predetermined electrical properties is disclosed. The bandpass photodetector detects electromagnetic radiation between a lower transition wavelength and an upper transition wavelength. That detector comprises two low pass photodetectors. The response of the two low pass photodetectors is subtracted to yield a response signal. 24 figs.

  18. Photodetectors using III-V nitrides

    DOE Patents [OSTI]

    Moustakas, Theodore D.

    1998-01-01

    A bandpass photodetector using a III-V nitride and having predetermined electrical properties. The bandpass photodetector detects electromagnetic radiation between a lower transition wavelength and an upper transition wavelength. That detector comprises two low pass photodetectors. The response of the two low pass photodetectors is subtracted to yield a response signal.

  19. Boron nitride solid state neutron detector

    DOE Patents [OSTI]

    Doty, F. Patrick

    2004-04-27

    The present invention describes an apparatus useful for detecting neutrons, and particularly for detecting thermal neutrons, while remaining insensitive to gamma radiation. Neutrons are detected by direct measurement of current pulses produced by an interaction of the neutrons with hexagonal pyrolytic boron nitride.

  20. Titanium nitride electrodes for thermoelectric generators

    DOE Patents [OSTI]

    Novak, Robert F. (Farmington Hills, MI); Schmatz, Duane J. (Dearborn Heights, MI); Hunt, Thomas K. (Ann Arbor, MI)

    1987-12-22

    The invention is directed to a composite article suitable for use in thermoelectric generators. The article comprises a thin film of titanium nitride as an electrode deposited onto solid electrolyte. The invention is also directed to the method of making same.

  1. Intrinsic ferromagnetism in hexagonal boron nitride nanosheets

    SciTech Connect (OSTI)

    Si, M. S.; Gao, Daqiang E-mail: xueds@lzu.edu.cn; Yang, Dezheng; Peng, Yong; Zhang, Z. Y.; Xue, Desheng E-mail: xueds@lzu.edu.cn; Liu, Yushen; Deng, Xiaohui; Zhang, G. P.

    2014-05-28

    Understanding the mechanism of ferromagnetism in hexagonal boron nitride nanosheets, which possess only s and p electrons in comparison with normal ferromagnets based on localized d or f electrons, is a current challenge. In this work, we report an experimental finding that the ferromagnetic coupling is an intrinsic property of hexagonal boron nitride nanosheets, which has never been reported before. Moreover, we further confirm it from ab initio calculations. We show that the measured ferromagnetism should be attributed to the localized π states at edges, where the electron-electron interaction plays the role in this ferromagnetic ordering. More importantly, we demonstrate such edge-induced ferromagnetism causes a high Curie temperature well above room temperature. Our systematical work, including experimental measurements and theoretical confirmation, proves that such unusual room temperature ferromagnetism in hexagonal boron nitride nanosheets is edge-dependent, similar to widely reported graphene-based materials. It is believed that this work will open new perspectives for hexagonal boron nitride spintronic devices.

  2. Silicon nitride having a high tensile strength

    DOE Patents [OSTI]

    Pujari, Vimal K. (Northboro, MA); Tracey, Dennis M. (Medfield, MA); Foley, Michael R. (Oxford, MA); Paille, Norman I. (Oxford, MA); Pelletier, Paul J. (Millbury, MA); Sales, Lenny C. (Grafton, MA); Willkens, Craig A. (Sterling, MA); Yeckley, Russell L. (Oakham, MA)

    1996-01-01

    A silicon nitride ceramic comprising: a) inclusions no greater than 25 microns in length, b) agglomerates no greater than 20 microns in diameter, and c) a surface finish of less than about 8 microinches, said ceramic having a four-point flexural strength of at least about 900 MPa.

  3. Silicon nitride having a high tensile strength

    DOE Patents [OSTI]

    Pujari, V.K.; Tracey, D.M.; Foley, M.R.; Paille, N.I.; Pelletier, P.J.; Sales, L.C.; Willkens, C.A.; Yeckley, R.L.

    1996-11-05

    A silicon nitride ceramic is disclosed comprising: (a) inclusions no greater than 25 microns in length, (b) agglomerates no greater than 20 microns in diameter, and (c) a surface finish of less than about 8 microinches, said ceramic having a four-point flexural strength of at least about 900 MPa. 4 figs.

  4. Fabrication and characterization of hexagonal boron nitride powder by spray drying and calcining-nitriding technology

    SciTech Connect (OSTI)

    Shi Xiaoliang Wang Sheng; Yang Hua; Duan Xinglong; Dong Xuebin

    2008-09-15

    Hexagonal boron nitride (hBN) powder was fabricated prepared by the spray drying and calcining-nitriding technology. The effects of nitrided temperature on the phases, morphology and particle size distribution of hBN powder, were investigated. The synthesized powders were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), Fourier transformed infrared spectrum, ultraviolet-visible (UV-vis) spectrum and photoluminescence (PL) spectrum. UV-vis spectrum revealed that the product had one obvious band gap (4.7 eV) and PL spectrum showed that it had a visible emission at 457 nm ({lambda}{sub ex}=230 nm). FESEM image indicated that the particle size of the synthesized hBN was mainly in the range of 0.5-1.5 {mu}m in diameter, and 50-150 nm in thickness. The high-energy ball-milling process following 900 deg. C calcining process was very helpful to obtain fully crystallized hBN at lower temperature. - Graphical abstract: hBN powder was fabricated prepared by spray drying and calcining-nitriding technology. The results indicated that spray drying and calcining-nitriding technology assisted with high-energy ball-milling process following calcined process was a hopeful way to manufacture hBN powder with high crystallinity in industrial scale.

  5. Synthesis and characterization of nitrides of iridium and palladiums

    SciTech Connect (OSTI)

    Crowhurst, Jonathan C.; Goncharov, Alexander F.; Sadigh, B.; Zaug, J.M.; Aberg, D.; Meng, Yue; Prakapenka, Vitali B.

    2008-08-14

    We describe the synthesis of nitrides of iridium and palladium using the laser-heated diamond anvil cell. We have used the in situ techniques of x-ray powder diffraction and Raman scattering to characterize these compounds and have compared our experimental findings where possible to the results of first-principles theoretical calculations. We suggest that palladium nitride is isostructural with pyrite, while iridium nitride has a monoclinic symmetry and is isostructural with baddeleyite.

  6. Low-loss binder for hot pressing boron nitride

    DOE Patents [OSTI]

    Maya, Leon (Oak Ridge, TN)

    1991-01-01

    Borazine derivatives used as low-loss binders and precursors for making ceramic boron nitride structures. The derivative forms the same composition as the boron nitride starting material, thereby filling the voids with the same boron nitride material upon forming and hot pressing. The derivatives have a further advantage of being low in carbon thus resulting in less volatile byproduct that can result in bubble formation during pressing.

  7. Method for locating metallic nitride inclusions in metallic alloy ingots

    DOE Patents [OSTI]

    White, Jack C. (Albany, OR); Traut, Davis E. (Corvallis, OR); Oden, Laurance L. (Albany, OR); Schmitt, Roman A. (Corvallis, OR)

    1992-01-01

    A method of determining the location and history of metallic nitride and/or oxynitride inclusions in metallic melts. The method includes the steps of labeling metallic nitride and/or oxynitride inclusions by making a coreduced metallic-hafnium sponge from a mixture of hafnium chloride and the chloride of a metal, reducing the mixed chlorides with magnesium, nitriding the hafnium-labeled metallic-hafnium sponge, and seeding the sponge to be melted with hafnium-labeled nitride inclusions. The ingots are neutron activated and the hafnium is located by radiometric means. Hafnium possesses exactly the proper metallurgical and radiochemical properties for this use.

  8. Metal/semiconductor phase transition in chromium nitride(001...

    Office of Scientific and Technical Information (OSTI)

    Metalsemiconductor phase transition in chromium nitride(001) grown by rf-plasma-assisted molecular-beam epitaxy Citation Details In-Document Search Title: Metalsemiconductor...

  9. Synthesis and characterisation of hexagonal molybdenum nitrides (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect Synthesis and characterisation of hexagonal molybdenum nitrides Citation Details In-Document Search Title: Synthesis and characterisation of hexagonal molybdenum nitrides Four hexagonal molybdenum nitrides-three modifications of {delta}-MoN and Mo{sub 5}N{sub 6}-were prepared by the plasma-enhanced chemical vapour deposition (PECVD) method and ammonolysis of MoCl{sub 5} and MoS{sub 2}. The nitrides were structurally characterised by X-ray diffraction,

  10. Recent Device Developments with Advanced Bulk Thermoelectric...

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

    Device Developments with Advanced Bulk Thermoelectric Materials at RTI Recent Device Developments with Advanced Bulk Thermoelectric Materials at RTI Reviews work in engineered ...

  11. RAPID/BulkTransmission | Open Energy Information

    Open Energy Info (EERE)

    regulatory processes and requirements by searching our regulatory flowchart library. Learn more about bulk transmission. BulkTransCoverage.png Regulations and permitting...

  12. Nanostructured High Temperature Bulk Thermoelectric Energy Conversion...

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

    High Temperature Bulk Thermoelectric Energy Conversion for Efficient Waste Heat Recovery Nanostructured High Temperature Bulk Thermoelectric Energy Conversion for Efficient Waste ...

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

    SciTech Connect (OSTI)

    Wampler, William R.; Modine, Normand A.

    2015-08-01

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

  14. Nitriding of super alloys for enhancing physical properties

    DOE Patents [OSTI]

    Purohit, A.

    1984-06-25

    The invention teaches the improvement of certain super alloys by exposing the alloy to an atmosphere of elemental nitrogen at elevated temperatures in excess of 750/sup 0/C but less than 1150/sup 0/C for an extended duration, viz., by nitriding the surface of the alloy, to establish barrier nitrides of the order of 25 to 100 micrometers thickness. These barrier

  15. Process for making boron nitride using sodium cyanide and boron

    DOE Patents [OSTI]

    Bamberger, Carlos E. (Oak Ridge, TN)

    1990-01-01

    This a very simple process for making boron nitride by mixing sodium cyanide and boron phosphate and heating the mixture in an inert atmosphere until a reaction takes place. The product is a white powder of boron nitride that can be used in applications that require compounds that are stable at high temperatures and that exhibit high electrical resistance.

  16. Molybdenum enhanced low-temperature deposition of crystalline silicon nitride

    DOE Patents [OSTI]

    Lowden, Richard A. (Powell, TN)

    1994-01-01

    A process for chemical vapor deposition of crystalline silicon nitride which comprises the steps of: introducing a mixture of a silicon source, a molybdenum source, a nitrogen source, and a hydrogen source into a vessel containing a suitable substrate; and thermally decomposing the mixture to deposit onto the substrate a coating comprising crystalline silicon nitride containing a dispersion of molybdenum silicide.

  17. Process for producing ceramic nitrides anc carbonitrides and their precursors

    DOE Patents [OSTI]

    Brown, G.M.; Maya, L.

    1987-02-25

    A process for preparing ceramic nitrides and carbon nitrides in the form of very pure, fine particulate powder. Appropriate precursors is prepared by reaching a transition metal alkylamide with ammonia to produce a mixture of metal amide and metal imide in the form of an easily pyrolyzable precipitate.

  18. Magnesium doping of boron nitride nanotubes

    DOE Patents [OSTI]

    Legg, Robert; Jordan, Kevin

    2015-06-16

    A method to fabricate boron nitride nanotubes incorporating magnesium diboride in their structure. In a first embodiment, magnesium wire is introduced into a reaction feed bundle during a BNNT fabrication process. In a second embodiment, magnesium in powder form is mixed into a nitrogen gas flow during the BNNT fabrication process. MgB.sub.2 yarn may be used for superconducting applications and, in that capacity, has considerably less susceptibility to stress and has considerably better thermal conductivity than these conventional materials when compared to both conventional low and high temperature superconducting materials.

  19. Stability analysis of zigzag boron nitride nanoribbons

    SciTech Connect (OSTI)

    Rai, Hari Mohan Late, Ravikiran; Saxena, Shailendra K.; Kumar, Rajesh; Sagdeo, Pankaj R.; Jaiswal, Neeraj K.; Srivastava, Pankaj

    2015-05-15

    We have explored the structural stability of bare and hydrogenated zigzag boron nitride nanoribbons (ZBNNRs). In order to investigate the structural stability, we calculate the cohesive energy for bare, one-edge and both edges H-terminated ZBNNRs with different widths. It is found that the ZBNNRs with width Nz=8 are energetically more favorable than the lower-width counterparts (Nz<8). Bare ZBNNRs have been found energetically most stable as compared to the edge terminated ribbons. Our analysis reveals that the structural stability is a function of ribbon-width and it is not affected significantly by the type of edge-passivation (one-edge or both-edges)

  20. Nanowire-templated lateral epitaxial growth of non-polar group III nitrides

    DOE Patents [OSTI]

    Wang, George T. (Albuquerque, NM); Li, Qiming (Albuquerque, NM); Creighton, J. Randall (Albuquerque, NM)

    2010-03-02

    A method for growing high quality, nonpolar Group III nitrides using lateral growth from Group III nitride nanowires. The method of nanowire-templated lateral epitaxial growth (NTLEG) employs crystallographically aligned, substantially vertical Group III nitride nanowire arrays grown by metal-catalyzed metal-organic chemical vapor deposition (MOCVD) as templates for the lateral growth and coalescence of virtually crack-free Group III nitride films. This method requires no patterning or separate nitride growth step.

  1. Hard and low friction nitride coatings and methods for forming the same

    DOE Patents [OSTI]

    Erdemir, Ali (Naperville, IL); Urgen, Mustafa (Istanbul, TR); Cakir, Ali Fuat (Istanbul, TR); Eryilmaz, Osman Levent (Bolingbrook, IL); Kazmanli, Kursat (Istanbul, TR); Keles, Ozgul (Istanbul, TR)

    2007-05-01

    An improved coating material possessing super-hard and low friction properties and a method for forming the same. The improved coating material includes the use of a noble metal or soft metal homogeneously distributed within a hard nitride material. The addition of small amounts of such metals into nitrides such as molybdenum nitride, titanium nitride, and chromium nitride results in as much as increasing of the hardness of the material as well as decreasing the friction coefficient and increasing the oxidation resistance.

  2. Cordierite silicon nitride filters. Final report

    SciTech Connect (OSTI)

    Sawyer, J.; Buchan, B.; Duiven, R.; Berger, M.; Cleveland, J.; Ferri, J.

    1992-02-01

    The objective of this project was to develop a silicon nitride based crossflow filter. This report summarizes the findings and results of the project. The project was phased with Phase I consisting of filter material development and crossflow filter design. Phase II involved filter manufacturing, filter testing under simulated conditions and reporting the results. In Phase I, Cordierite Silicon Nitride (CSN) was developed and tested for permeability and strength. Target values for each of these parameters were established early in the program. The values were met by the material development effort in Phase I. The crossflow filter design effort proceeded by developing a macroscopic design based on required surface area and estimated stresses. Then the thermal and pressure stresses were estimated using finite element analysis. In Phase II of this program, the filter manufacturing technique was developed, and the manufactured filters were tested. The technique developed involved press-bonding extruded tiles to form a filter, producing a monolithic filter after sintering. Filters manufactured using this technique were tested at Acurex and at the Westinghouse Science and Technology Center. The filters did not delaminate during testing and operated and high collection efficiency and good cleanability. Further development in areas of sintering and filter design is recommended.

  3. Silicon nitride protective coatings for silvered glass mirrors

    DOE Patents [OSTI]

    Tracy, C.E.; Benson, D.K.

    1984-07-20

    A protective diffusion barrier for metalized mirror structures is provided by a layer or coating of silicon nitride which is a very dense, transparent, dielectric material that is impervious to water, alkali, and other impurities and corrosive substances that typically attack the metal layers of mirrors and cause degradation of the mirrors' reflectivity. The silicon nitride layer can be deposited on the substrate prior to metal deposition thereon to stabilize the metal/substrate interface, and it can be deposited over the metal to encapsulate it and protect the metal from corrosion or other degradation. Mirrors coated with silicon nitride according to this invention can also be used as front surface mirrors.

  4. Conductive and robust nitride buffer layers on biaxially textured substrates

    DOE Patents [OSTI]

    Sankar, Sambasivan; Goyal, Amit; Barnett, Scott A.; Kim, Ilwon; Kroeger, Donald M.

    2004-08-31

    The present invention relates to epitaxial, electrically conducting and mechanically robust, cubic nitride buffer layers deposited epitaxially on biaxially textured substrates such as metal and alloys. The invention comprises of a biaxially textured substrate with epitaxial layers of nitrides. The invention also discloses a method to form such epitaxial layers using a high rate deposition method as well as without the use of forming gases. The invention further comprises epitaxial layers of oxides on the biaxially textured nitride layers. In some embodiments the article further comprises electromagnetic devices which may be super conducting properties.

  5. Nitriding of super alloys for enhancing physical properties

    DOE Patents [OSTI]

    Purohit, Ankur (Lisle, IL)

    1986-01-01

    The invention teaches the improvement of certain super alloys by exposing the alloy to an atmosphere of elemental nitrogen at elevated temperatures in excess of 750.degree. C. but less than 1150.degree. C. for an extended duration, viz., by nitriding the surface of the alloy, to establish barrier nitrides of the order of 25-100 micrometers thickness. These barrier nitrides appear to shield the available oxidizing metallic species of the alloy for up to a sixfold improved resistance against oxidation and also appear to impede egress of surface dislocations for increased fatigue and creep strengths.

  6. High efficiency III-nitride light-emitting diodes

    DOE Patents [OSTI]

    Crawford, Mary; Koleske, Daniel; Cho, Jaehee; Zhu, Di; Noemaun, Ahmed; Schubert, Martin F; Schubert, E. Fred

    2013-05-28

    Tailored doping of barrier layers enables balancing of the radiative recombination among the multiple-quantum-wells in III-Nitride light-emitting diodes. This tailored doping enables more symmetric carrier transport and uniform carrier distribution which help to reduce electron leakage and thus reduce the efficiency droop in high-power III-Nitride LEDs. Mitigation of the efficiency droop in III-Nitride LEDs may enable the pervasive market penetration of solid-state-lighting technologies in high-power lighting and illumination.

  7. Conductive and robust nitride buffer layers on biaxially textured substrates

    DOE Patents [OSTI]

    Sankar, Sambasivan [Chicago, IL; Goyal, Amit [Knoxville, TN; Barnett, Scott A [Evanston, IL; Kim, Ilwon [Skokie, IL; Kroeger, Donald M [Knoxville, TN

    2009-03-31

    The present invention relates to epitaxial, electrically conducting and mechanically robust, cubic nitride buffer layers deposited epitaxially on biaxially textured substrates such as metals and alloys. The invention comprises of a biaxially textured substrate with epitaxial layers of nitrides. The invention also discloses a method to form such epitaxial layers using a high rate deposition method as well as without the use of forming gases. The invention further comprises epitaxial layers of oxides on the biaxially textured nitride layer. In some embodiments the article further comprises electromagnetic devices which may have superconducting properties.

  8. Silicon nitride protective coatings for silvered glass mirrors

    DOE Patents [OSTI]

    Tracy, C. Edwin (Golden, CO); Benson, David K. (Golden, CO)

    1988-01-01

    A protective diffusion barrier for metalized mirror structures is provided by a layer or coating of silicon nitride which is a very dense, transparent, dielectric material that is impervious to water, alkali, and other impurities and corrosive substances that typically attack the metal layers of mirrors and cause degradation of the mirrors' reflectivity. The silicon nitride layer can be deposited on the substrate before metal deposition to stabilize the metal/substrate interface, and it can be deposited over the metal to encapsulate it and protect the metal from corrosion or other degradation. Mirrors coated with silicon nitride according to this invention can also be used as front surface mirrors.

  9. Iron-Nitride Alloy Magnets: Transformation Enabled Nitride Magnets Absent Rare Earths (TEN Mare)

    SciTech Connect (OSTI)

    2012-01-01

    REACT Project: Case Western is developing a highly magnetic iron-nitride alloy to use in the magnets that power electric motors found in EVs and renewable power generators. This would reduce the overall price of the motor by eliminating the expensive imported rare earth minerals typically found in todays best commercial magnets. The iron-nitride powder is sourced from abundant and inexpensive materials found in the U.S. The ultimate goal of this project is to demonstrate this new magnet system, which contains no rare earths, in a prototype electric motor. This could significantly reduce the amount of greenhouse gases emitted in the U.S. each year by encouraging the use of clean alternatives to oil and coal.

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

    DOE Patents [OSTI]

    Marks, Tobin J. (Evanston, IL); Chen, You-Xian (Midland, MI)

    2001-01-01

    The (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium are novel weakly coordinating anions which are highly fluorinated. (Polyfluoroaryl)fluoroanions of one such type contain at least one ring substituent other than fluorine. These (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium have greater solubility in organic solvents, or have a coordinative ability essentially equal to or less than that of the corresponding (polyfluoroaryl)fluoroanion of aluminum, gallium, or indium in which the substituent is replaced by fluorine. Another type of new (polyfluoroaryl)fluoroanion of aluminum, gallium, and indium have 1-3 perfluorinated fused ring groups and 2-0 perfluorophenyl groups. When used as a cocatalyst in the formation of novel catalytic complexes with d- or f-block metal compounds having at least one leaving group such as a methyl group, these anions, because of their weak coordination to the metal center, do not interfere in the ethylene polymerization process, while affecting the propylene process favorably, if highly isotactic polypropylene is desired. Thus, the (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium of this invention are useful in various polymerization processes such as are described.

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

    DOE Patents [OSTI]

    Marks, Tobin J. (Evanston, IL); Chen, You-Xian (Midland, MI)

    2002-01-01

    The (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium are novel weakly coordinating anions which are highly fluorinated. (Polyfluoroaryl)fluoroanions of one such type contain at least one ring substituent other than fluorine. These (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium have greater solubility in organic solvents, or have a coordinative ability essentially equal to or less than that of the corresponding (polyfluoroaryl)fluoroanion of aluminum, gallium, or indium in which the substituent is replaced by fluorine. Another type of new (polyfluoroaryl)fluoroanion of aluminum, gallium, and indium have 1-3 perfluorinated fused ring groups and 2-0 perfluorophenyl groups. When used as a cocatalyst in the formation of novel catalytic complexes with d- or f-block metal compounds having at least one leaving group such as a methyl group, these anions, because of their weak coordination to the metal center, do not interfere in the ethylene polymerization process, while affecting the propylene process favorably, if highly isotactic polypropylene is desired. Thus, the (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium of this invention are useful in various polymerization processes such as are described.

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

    SciTech Connect (OSTI)

    Kohlmann, H.

    2010-02-15

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

  13. Spin-phonon coupling in scandium doped gallium ferrite

    SciTech Connect (OSTI)

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

    2015-03-28

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

  14. Process for manufacture of semipermeable silicon nitride membranes

    DOE Patents [OSTI]

    Galambos, Paul Charles; Shul, Randy J.; Willison, Christi Gober

    2003-12-09

    A new class of semipermeable membranes, and techniques for their fabrication, have been developed. These membranes, formed by appropriate etching of a deposited silicon nitride layer, are robust, easily manufacturable, and compatible with a wide range of silicon micromachining techniques.

  15. Process for preparing titanium nitride powder

    DOE Patents [OSTI]

    Bamberger, C.E.

    1988-06-17

    A process for making titanium nitride powder by reaction of titanium phosphates with sodium cyanide. The process of this invention may comprise mixing one or more phosphates of Ti with a cyanide salt in the absence of oxygen and heating to a temperature sufficient to cause reaction to occur. In the preferred embodiment the ratio of cyanide salt to Ti should be at least 2 which results in the major Ti-containing product being TiN rather than sodium titanium phosphate byproducts. The process is an improvement over prior processes since the byproducts are water soluble salts of sodium which can easily be removed from the preferred TiN product by washing. 2 tabs.

  16. Apparatus for silicon nitride precursor solids recovery

    DOE Patents [OSTI]

    Crosbie, Gary M. (Dearborn, MI); Predmesky, Ronald L. (Livonia, MI); Nicholson, John M. (Wayne, MI)

    1995-04-04

    Method and apparatus are provided for collecting reaction product solids entrained in a gaseous outflow from a reaction situs, wherein the gaseous outflow includes a condensable vapor. A condensate is formed of the condensable vapor on static mixer surfaces within a static mixer heat exchanger. The entrained reaction product solids are captured in the condensate which can be collected for further processing, such as return to the reaction situs. In production of silicon imide, optionally integrated into a production process for making silicon nitride caramic, wherein reactant feed gas comprising silicon halide and substantially inert carrier gas is reacted with liquid ammonia in a reaction vessel, silicon imide reaction product solids entrained in a gaseous outflow comprising residual carrier gas and vaporized ammonia can be captured by forming a condensate of the ammonia vapor on static mixer surfaces of a static mixer heat exchanger.

  17. Method for silicon nitride precursor solids recovery

    DOE Patents [OSTI]

    Crosbie, Gary M. (Dearborn, MI); Predmesky, Ronald L. (Livonia, MI); Nicholson, John M. (Wayne, MI)

    1992-12-15

    Method and apparatus are provided for collecting reaction product solids entrained in a gaseous outflow from a reaction situs, wherein the gaseous outflow includes a condensable vapor. A condensate is formed of the condensable vapor on static mixer surfaces within a static mixer heat exchanger. The entrained reaction product solids are captured in the condensate which can be collected for further processing, such as return to the reaction situs. In production of silicon imide, optionally integrated into a production process for making silicon nitride caramic, wherein reactant feed gas comprising silicon halide and substantially inert carrier gas is reacted with liquid ammonia in a reaction vessel, silicon imide reaction product solids entrained in a gaseous outflow comprising residual carrier gas and vaporized ammonia can be captured by forming a condensate of the ammonia vapor on static mixer surfaces of a static mixer heat exchanger.

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

    SciTech Connect (OSTI)

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

    2013-12-15

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

  19. Apparatus for the production of boron nitride nanotubes

    SciTech Connect (OSTI)

    Smith, Michael W; Jordan, Kevin

    2014-06-17

    An apparatus for the large scale production of boron nitride nanotubes comprising; a pressure chamber containing; a continuously fed boron containing target; a source of thermal energy preferably a focused laser beam; a cooled condenser; a source of pressurized nitrogen gas; and a mechanism for extracting boron nitride nanotubes that are condensed on or in the area of the cooled condenser from the pressure chamber.

  20. Molybdenum enhanced low-temperature deposition of crystalline silicon nitride

    DOE Patents [OSTI]

    Lowden, R.A.

    1994-04-05

    A process for chemical vapor deposition of crystalline silicon nitride is described which comprises the steps of: introducing a mixture of a silicon source, a molybdenum source, a nitrogen source, and a hydrogen source into a vessel containing a suitable substrate; and thermally decomposing the mixture to deposit onto the substrate a coating comprising crystalline silicon nitride containing a dispersion of molybdenum silicide. 5 figures.

  1. Nanostructure, Chemistry and Crystallography of Iron Nitride Magnetic

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

    Materials by Ultra-High-Resolution Electron Microscopy and Related Methods | Department of Energy Nanostructure, Chemistry and Crystallography of Iron Nitride Magnetic Materials by Ultra-High-Resolution Electron Microscopy and Related Methods Nanostructure, Chemistry and Crystallography of Iron Nitride Magnetic Materials by Ultra-High-Resolution Electron Microscopy and Related Methods 2011 DOE Hydrogen and Fuel Cells Program, and Vehicle Technologies Program Annual Merit Review and Peer

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

    SciTech Connect (OSTI)

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

    2015-05-15

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

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

    SciTech Connect (OSTI)

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

    2014-02-01

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

  4. Thermoelectric Bulk Materials from the Explosive Consolidation...

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

    Thermoelectric Bulk Materials from the Explosive Consolidation of Nanopowders Describes technique of explosively consolidating nanopowders to yield fully dense, consolidated, ...

  5. Spherical boron nitride particles and method for preparing them

    DOE Patents [OSTI]

    Phillips, Jonathan; Gleiman, Seth S.; Chen, Chun-Ku

    2003-11-25

    Spherical and polyhedral particles of boron nitride and method of preparing them. Spherical and polyhedral particles of boron nitride are produced from precursor particles of hexagonal phase boron nitride suspended in an aerosol gas. The aerosol is directed to a microwave plasma torch. The torch generates plasma at atmospheric pressure that includes nitrogen atoms. The presence of nitrogen atoms is critical in allowing boron nitride to melt at atmospheric pressure while avoiding or at least minimizing decomposition. The plasma includes a plasma hot zone, which is a portion of the plasma that has a temperature sufficiently high to melt hexagonal phase boron nitride. In the hot zone, the precursor particles melt to form molten particles that acquire spherical and polyhedral shapes. These molten particles exit the hot zone, cool, and solidify to form solid particles of boron nitride with spherical and polyhedral shapes. The molten particles can also collide and join to form larger molten particles that lead to larger spherical and polyhedral particles.

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

    SciTech Connect (OSTI)

    Morris, R.N.

    1998-08-01

    This report summarizes the results of the Gallium-Clad interactions Phase 3 and 4 tasks. Both tasks were to involve examining the out-of-pile stability of residual gallium in short fuel rods with an imposed thermal gradient. The thermal environment was to be created by an electrical heater in the center of the fuel rod and coolant flow on the rod outer cladding. Both tasks were canceled due to difficulties with fuel pellet fabrication, delays in the preparation of the test apparatus, and changes in the Fissile Materials Disposition program budget.

  7. RAPID/BulkTransmission/Air Quality | Open Energy Information

    Open Energy Info (EERE)

    BulkTransmissionAir Quality < RAPID | BulkTransmission Jump to: navigation, search RAPID Regulatory and Permitting Information Desktop Toolkit BETA About Bulk Transmission...

  8. Silicon nitride/silicon carbide composite densified materials prepared using composite powders

    DOE Patents [OSTI]

    Dunmead, S.D.; Weimer, A.W.; Carroll, D.F.; Eisman, G.A.; Cochran, G.A.; Susnitzky, D.W.; Beaman, D.R.; Nilsen, K.J.

    1997-07-01

    Prepare silicon nitride-silicon carbide composite powders by carbothermal reduction of crystalline silica powder, carbon powder and, optionally, crystalline silicon nitride powder. The crystalline silicon carbide portion of the composite powders has a mean number diameter less than about 700 nanometers and contains nitrogen. The composite powders may be used to prepare sintered ceramic bodies and self-reinforced silicon nitride ceramic bodies.

  9. RAPID/Bulk Transmission | Open Energy Information

    Open Energy Info (EERE)

    Page Edit History RAPIDBulk Transmission < RAPID(Redirected from RAPIDOverviewBulkTransmission) Redirect page Jump to: navigation, search REDIRECT RAPIDBulkTransmission...

  10. CX-000845: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

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

  11. Active Control of Nitride Plasmonic Dispersion in the Far Infrared.

    SciTech Connect (OSTI)

    Shaner, Eric A.; Dyer, Gregory Conrad; Seng, William Francis; Bethke, Donald Thomas; Grine, Albert Dario,; Baca, Albert G.; Allerman, Andrew A.

    2014-11-01

    We investigate plasmonic structures in nitride-based materials for far-infrared (IR) applications. The two dimensional electron gas (2DEG) in the GaN/AlGaN material system, much like metal- dielectric structures, is a patternable plasmonic medium. However, it also permits for direct tunability via an applied voltage. While there have been proof-of-principle demonstrations of plasma excitations in nitride 2DEGs, exploration of the potential of this material system has thus far been limited. We recently demonstrated coherent phenomena such as the formation of plasmonic crystals, strong coupling of tunable crystal defects to a plasmonic crystal, and electromagnetically induced transparency in GaAs/AlGaAs 2DEGs at sub-THz frequencies. In this project, we explore whether these effects can be realized in nitride 2DEG materials above 1 THz and at temperatures exceeding 77 K.

  12. Cooled silicon nitride stationary turbine vane risk reduction. Final report

    SciTech Connect (OSTI)

    Holowczak, John

    1999-12-31

    The purpose of this program was to reduce the technical risk factors for demonstration of air cooled silicon nitride turbine vanes. The effort involved vane prototype fabrication efforts at two U.S. based gas turbine grade silicon nitride component manufacturers. The efficacy of the cooling system was analyzed via a thermal time/temperature flow test technique previously at UTRC. By having multiple vendors work on parts fabrication, the chance of program success increased for producing these challenging components. The majority of the effort under this contract focused on developing methods for, and producing, the complex thin walled silicon nitride vanes. Components developed under this program will undergo engine environment testing within N00014-96-2-0014.

  13. Structural studies of magnesium nitride fluorides by powder neutron diffraction

    SciTech Connect (OSTI)

    Brogan, Michael A.; Hughes, Robert W.; Smith, Ronald I.; Gregory, Duncan H.

    2012-01-15

    Samples of ternary nitride fluorides, Mg{sub 3}NF{sub 3} and Mg{sub 2}NF have been prepared by solid state reaction of Mg{sub 3}N{sub 2} and MgF{sub 2} at 1323-1423 K and investigated by powder X-ray and powder neutron diffraction techniques. Mg{sub 3}NF{sub 3} is cubic (space group: Pm3m) and has a structure related to rock-salt MgO, but with one cation site vacant. Mg{sub 2}NF is tetragonal (space group: I4{sub 1}/amd) and has an anti-LiFeO{sub 2} related structure. Both compounds are essentially ionic and form structures in which nitride and fluoride anions are crystallographically ordered. The nitride fluorides show temperature independent paramagnetic behaviour between 5 and 300 K. - Graphical abstract: Definitive structures of the ternary magnesium nitride fluorides Mg{sub 3}NF{sub 3} and the lower temperature polymorph of Mg{sub 2}NF have been determined from powder neutron diffraction data. The nitride halides are essentially ionic and exhibit weak temperature independent paramagnetic behaviour. Highlights: Black-Right-Pointing-Pointer Definitive structures of Mg{sub 3}NF{sub 3} and Mg{sub 2}NF were determined by neutron diffraction. Black-Right-Pointing-Pointer Nitride and fluoride anions are crystallographically ordered in both structures. Black-Right-Pointing-Pointer Both compounds exhibit weak, temperature independent paramagnetic behaviour. Black-Right-Pointing-Pointer The compounds are essentially ionic with ionicity increasing with F{sup -} content.

  14. First-principles study on the interaction of nitrogen atom with ?uranium: From surface adsorption to bulk diffusion

    SciTech Connect (OSTI)

    Su, Qiulei; Deng, Huiqiu E-mail: hqdeng@gmail.com; Xiao, Shifang; Li, Xiaofan; Hu, Wangyu; Ao, Bingyun; Chen, Piheng

    2014-04-28

    Experimental studies of nitriding on uranium surfaces show that the modified layers provide considerable protection against air corrosion. The bimodal distribution of nitrogen is affected by both its implantation and diffusion, and the diffusion of nitrogen during implantation is also governed by vacancy trapping. In the present paper, nitrogen adsorption, absorption, diffusion, and vacancy trapping on the surface of and in the bulk of ?uranium are studied with a first-principles density functional theory approach and the climbing image nudged elastic band method. The calculated results indicate that, regardless of the nitrogen coverage, a nitrogen atom prefers to reside at the hollow1 site and octahedral (Oct) site on and below the surface, respectively. The lowest energy barriers for on-surface and penetration diffusion occur at a coverage of 1/2 monolayer. A nitrogen atom prefers to occupy the Oct site in bulk ?uranium. High energy barriers are observed during the diffusion between neighboring Oct sites. A vacancy can capture its nearby interstitial nitrogen atom with a low energy barrier, providing a significant attractive nitrogen-vacancy interaction at the trapping center site. This study provides a reference for understanding the nitriding process on uranium surfaces.

  15. Synthesis of uranium nitride and uranium carbide powder by carbothermic reduction

    SciTech Connect (OSTI)

    Dunwoody, J.T.; Stanek, C.R.; McClellan, K.J.; Voit, S.L.; Volz, H.M.; Hickman, R.R.

    2007-07-01

    Uranium nitride and uranium carbide are being considered as high burnup fuels in next generation nuclear reactors and accelerated driven systems for the transmutation of nuclear waste. The same characteristics that make nitrides and carbides candidates for these applications (i.e. favorable thermal properties, mutual solubility of nitrides, etc.), also make these compositions candidate fuels for space nuclear reactors. In this paper, we discuss the synthesis and characterization of depleted uranium nitride and carbide for a space nuclear reactor program. Importantly, this project emphasized that to synthesize high quality uranium nitride and carbide, it is necessary to understand the exact stoichiometry of the oxide feedstock. (authors)

  16. Process for synthesizing titanium carbide, titanium nitride and titanium carbonitride

    DOE Patents [OSTI]

    Koc, Rasit (Lakewood, CO); Glatzmaier, Gregory C. (Boulder, CO)

    1995-01-01

    A process for synthesizing titanium carbide, titanium nitride or titanium carbonitride. The process comprises placing particles of titanium, a titanium salt or titanium dioxide within a vessel and providing a carbon-containing atmosphere within the vessel. The vessel is heated to a pyrolysis temperature sufficient to pyrolyze the carbon to thereby coat the particles with a carbon coating. Thereafter, the carbon-coated particles are heated in an inert atmosphere to produce titanium carbide, or in a nitrogen atmosphere to produce titanium nitride or titanium carbonitride, with the heating being of a temperature and time sufficient to produce a substantially complete solid solution.

  17. Process for synthesizing titanium carbide, titanium nitride and titanium carbonitride

    DOE Patents [OSTI]

    Koc, R.; Glatzmaier, G.C.

    1995-05-23

    A process is disclosed for synthesizing titanium carbide, titanium nitride or titanium carbonitride. The process comprises placing particles of titanium, a titanium salt or titanium dioxide within a vessel and providing a carbon-containing atmosphere within the vessel. The vessel is heated to a pyrolysis temperature sufficient to pyrolyze the carbon to thereby coat the particles with a carbon coating. Thereafter, the carbon-coated particles are heated in an inert atmosphere to produce titanium carbide, or in a nitrogen atmosphere to produce titanium nitride or titanium carbonitride, with the heating being of a temperature and time sufficient to produce a substantially complete solid solution.

  18. Synthesis and Optimization of the Sintering Kinetics of Actinide Nitrides

    SciTech Connect (OSTI)

    Drryl P. Butt; Brian Jaques

    2009-03-31

    Research conducted for this NERI project has advanced the understanding and feasibility of nitride nuclear fuel processing. In order to perform this research, necessary laboratory infrastructure was developed; including basic facilities and experimental equipment. Notable accomplishments from this project include: the synthesis of uranium, dysprosium, and cerium nitrides using a novel, low-cost mechanical method at room temperature; the synthesis of phase pure UN, DyN, and CeN using thermal methods; and the sintering of UN and (Ux, Dy1-x)N (0.7 ≤ X ≤ 1) pellets from phase pure powder that was synthesized in the Advanced Materials Laboratory at Boise State University.

  19. Communication: Water on hexagonal boron nitride from diffusion Monte Carlo

    SciTech Connect (OSTI)

    Al-Hamdani, Yasmine S.; Ma, Ming; Michaelides, Angelos; Alf, Dario; Lilienfeld, O. Anatole von

    2015-05-14

    Despite a recent flurry of experimental and simulation studies, an accurate estimate of the interaction strength of water molecules with hexagonal boron nitride is lacking. Here, we report quantum Monte Carlo results for the adsorption of a water monomer on a periodic hexagonal boron nitride sheet, which yield a water monomer interaction energy of ?84 5 meV. We use the results to evaluate the performance of several widely used density functional theory (DFT) exchange correlation functionals and find that they all deviate substantially. Differences in interaction energies between different adsorption sites are however better reproduced by DFT.

  20. Process for producing wurtzitic or cubic boron nitride

    DOE Patents [OSTI]

    Holt, J.B.; Kingman, D.D.; Bianchini, G.M.

    1992-04-28

    Disclosed is a process for producing wurtzitic or cubic boron nitride comprising the steps of: [A] preparing an intimate mixture of powdered boron oxide, a powdered metal selected from the group consisting of magnesium or aluminum, and a powdered metal azide; [B] igniting the mixture and bringing it to a temperature at which self-sustaining combustion occurs; [C] shocking the mixture at the end of the combustion thereof with a high pressure wave, thereby forming as a reaction product, wurtzitic or cubic boron nitride and occluded metal oxide; and, optionally [D] removing the occluded metal oxide from the reaction product. Also disclosed are reaction products made by the process described.

  1. Process for producing amorphous and crystalline silicon nitride

    DOE Patents [OSTI]

    Morgan, P.E.D.; Pugar, E.A.

    1985-11-12

    A process for producing amorphous or crystalline silicon nitride is disclosed which comprises reacting silicon disulfide ammonia gas at elevated temperature. In a preferred embodiment silicon disulfide in the form of whiskers'' or needles is heated at temperature ranging from about 900 C to about 1,200 C to produce silicon nitride which retains the whisker or needle morphological characteristics of the silicon disulfide. Silicon carbide, e.g. in the form of whiskers, also can be prepared by reacting substituted ammonia, e.g. methylamine, or a hydrocarbon containing active hydrogen-containing groups, such as ethylene, with silicon disulfide, at elevated temperature, e.g. 900 C. 6 figs.

  2. 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.

  3. Continuous Fiber Ceramic Composite (CFCC) Program: Gaseous Nitridation

    SciTech Connect (OSTI)

    R. Suplinskas G. DiBona; W. Grant

    2001-10-29

    Textron has developed a mature process for the fabrication of continuous fiber ceramic composite (CFCC) tubes for application in the aluminum processing and casting industry. The major milestones in this project are System Composition; Matrix Formulation; Preform Fabrication; Nitridation; Material Characterization; Component Evaluation

  4. Methods for improved growth of group III nitride buffer layers

    DOE Patents [OSTI]

    Melnik, Yurity; Chen, Lu; Kojiri, Hidehiro

    2014-07-15

    Methods are disclosed for growing high crystal quality group III-nitride epitaxial layers with advanced multiple buffer layer techniques. In an embodiment, a method includes forming group III-nitride buffer layers that contain aluminum on suitable substrate in a processing chamber of a hydride vapor phase epitaxy processing system. A hydrogen halide or halogen gas is flowing into the growth zone during deposition of buffer layers to suppress homogeneous particle formation. Some combinations of low temperature buffers that contain aluminum (e.g., AlN, AlGaN) and high temperature buffers that contain aluminum (e.g., AlN, AlGaN) may be used to improve crystal quality and morphology of subsequently grown group III-nitride epitaxial layers. The buffer may be deposited on the substrate, or on the surface of another buffer. The additional buffer layers may be added as interlayers in group III-nitride layers (e.g., GaN, AlGaN, AlN).

  5. Lattice matched crystalline substrates for cubic nitride semiconductor growth

    DOE Patents [OSTI]

    Norman, Andrew G; Ptak, Aaron J; McMahon, William E

    2015-02-24

    Disclosed embodiments include methods of fabricating a semiconductor layer or device and devices fabricated thereby. The methods include, but are not limited to, providing a substrate having a cubic crystalline surface with a known lattice parameter and growing a cubic crystalline group III-nitride alloy layer on the cubic crystalline substrate by coincident site lattice matched epitaxy. The cubic crystalline group III-nitride alloy may be prepared to have a lattice parameter (a') that is related to the lattice parameter of the substrate (a). The group III-nitride alloy may be a cubic crystalline In.sub.xGa.sub.yAl.sub.1-x-yN alloy. The lattice parameter of the In.sub.xGa.sub.yAl.sub.1-x-yN or other group III-nitride alloy may be related to the substrate lattice parameter by (a')= 2(a) or (a')=(a)/ 2. The semiconductor alloy may be prepared to have a selected band gap.

  6. Process for producing ceramic nitrides and carbonitrides and their precursors

    DOE Patents [OSTI]

    Brown, Gilbert M. (Knoxville, TN); Maya, Leon (Oak Ridge, TN)

    1988-01-01

    A process for preparing ceramic nitrides and carbonitrides in the form of very pure, fine particulate powder. Appropriate precursor is prepared by reacting a transition metal alkylamide with ammonia to produce a mixture of metal amide and metal imide in the form of an easily pyrolyzable precipitate.

  7. bulk power system | OpenEI Community

    Open Energy Info (EERE)

    Dc(266) Contributor 31 October, 2014 - 10:58 What do you know about the grid? black out brown out bulk power system electricity grid future grid grid history security Smart Grid...

  8. RAPID/BulkTransmission/Transmission Siting & Interconnection...

    Open Energy Info (EERE)

    federal review). Bulk Transmission Transmission Siting & Interconnection in New Mexico New Mexico Statutes (N.M.S.) 62-9-1, 62-9-3(B), and 62-9-3.2 No Location Permit may be...

  9. Layered insulator hexagonal boron nitride for surface passivation in quantum dot solar cell

    SciTech Connect (OSTI)

    Shanmugam, Mariyappan; Jain, Nikhil; Jacobs-Gedrim, Robin; Yu, Bin; Xu, Yang

    2013-12-09

    Single crystalline, two dimensional (2D) layered insulator hexagonal boron nitride (h-BN), is demonstrated as an emerging material candidate for surface passivation on mesoporous TiO{sub 2}. Cadmium selenide (CdSe) quantum dot based bulk heterojunction (BHJ) solar cell employed h-BN passivated TiO{sub 2} as an electron acceptor exhibits photoconversion efficiency ?46% more than BHJ employed unpassivated TiO{sub 2}. Dominant interfacial recombination pathways such as electron capture by TiO{sub 2} surface states and recombination with hole at valence band of CdSe are efficiently controlled by h-BN enabled surface passivation, leading to improved photovoltaic performance. Highly crystalline, confirmed by transmission electron microscopy, dangling bond-free 2D layered h-BN with self-terminated atomic planes, achieved by chemical exfoliation, enables efficient passivation on TiO{sub 2}, allowing electronic transport at TiO{sub 2}/h-BN/CdSe interface with much lower recombination rate compared to an unpassivated TiO{sub 2}/CdSe interface.

  10. Progress of nitride fuel cycle research for transmutation of minor actinides

    SciTech Connect (OSTI)

    Arai, Yasuo; Akabori, Mitsuo; Minato, Kazuo

    2007-07-01

    Recent progress of nitride fuel cycle research for transmutation of MA is summarized. Preparation of MA-bearing nitride pellets, such as (Np,Am)N, (Am,Pu)N and (Np,Pu,Am,Cm)N, was carried out. Irradiation behavior of U-free nitride fuel was investigated by the irradiation test of (Pu,Zr)N and PuN+TiN fuels, in which ZrN and TiN were added as a possible diluent material. Further, pyrochemical process of spent nitride fuel was developed by electrorefining in a molten chloride salt and subsequent re-nitridation of actinides in liquid Cd cathode electro-deposits. Nitride fuel cycle for transmutation of MA has been demonstrated in a laboratory scale by the experimental study with MA and Pu. (authors)

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

    DOE Patents [OSTI]

    Marks, Tobin J. (Evanston, IL); Chen, You-Xian (Midland, MI)

    2001-01-01

    The (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium are novel weakly coordinating anions which are are highly fluorinated. (Polyfluoroaryl)fluoroanions of one such type contain at least one ring substituent other than fluorine. These (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium have greater solubility in organic solvents, or have a coordinative ability essentially equal to or less than that of the corresponding (polyfluoroaryl)fluoroanion of aluminum, gallium, or indium in which the substituent is replaced by fluorine. Another type of new (polyfluoroaryl)fluoroanion of aluminum, gallium, and indium have 1-3 perfluorinated fused ring groups and 2-0 perfluorophenyl groups. When used as a cocatalyst in the formation of novel catalytic complexes with d- or f-block metal compounds having at least one leaving group such as a methyl group, these anions, because of their weak coordination to the metal center, do not interefere in the ethylene polymerization process, while affecting the the propylene process favorably, if highly isotactic polypropylene is desired. Thus, the (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium of this invention are useful in various polymerization processes such as are described.

  12. Hetero-junctions of Boron Nitride and Carbon Nanotubes: Synthesis and

    Office of Scientific and Technical Information (OSTI)

    Characterization (Technical Report) | SciTech Connect Hetero-junctions of Boron Nitride and Carbon Nanotubes: Synthesis and Characterization Citation Details In-Document Search Title: Hetero-junctions of Boron Nitride and Carbon Nanotubes: Synthesis and Characterization Hetero-junctions of boron nitride nanotubes (BNNTs) and carbon nanotubes (CNTs) are expected to have appealing new properties that are not available from pure BNNTs and CNTs. Theoretical studies indicate that BNNT/CNT

  13. Lasers Used to Make First Boron-Nitride Nanotube Yarn | Jefferson Lab

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

    Lasers Used to Make First Boron-Nitride Nanotube Yarn Visualization of helium-4 and beryllium nuclei. A yarn spun of boron-nitride nanotubes suspends a quarter. NEWPORT NEWS, VA, Dec. 2 -Researchers have used lasers to create the first practical macroscopic yarns from boron nitride fibers, opening the door for an array of applications, from radiation-shielded spacecraft to stronger body armor, according to a just-published study. Researchers at NASA's Langley Research Center, the Department of

  14. Method and apparatus for use of III-nitride wide bandgap semiconductors in optical communications

    DOE Patents [OSTI]

    Hui, Rongqing (Lenexa, KS); Jiang,Hong-Xing (Manhattan, KS); Lin, Jing-Yu (Manhattan, KS)

    2008-03-18

    The present disclosure relates to the use of III-nitride wide bandgap semiconductor materials for optical communications. In one embodiment, an optical device includes an optical waveguide device fabricated using a III-nitride semiconductor material. The III-nitride semiconductor material provides for an electrically controllable refractive index. The optical waveguide device provides for high speed optical communications in an infrared wavelength region. In one embodiment, an optical amplifier is provided using optical coatings at the facet ends of a waveguide formed of erbium-doped III-nitride semiconductor materials.

  15. Boron-Nitride (BN) Nanotubes (BNNT) at TJNAF| U.S. DOE Office...

    Office of Science (SC) Website

    Boron-Nitride (BN) Nanotubes (BNNT) at TJNAF Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Applications of Nuclear Science Applications ...

  16. The phase diagram and hardness of carbon nitrides

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

    Dong, Huafeng; Oganov, Artem R.; Zhu, Qiang; Qian, Guang-Rui

    2015-05-06

    Novel superhard materials, especially those with superior thermal and chemical stability, are needed to replace diamond. Carbon nitrides (C-N), which are likely to possess these characteristics and have even been expected to be harder than diamond, are excellent candidates. Here we report three new superhard and thermodynamically stable carbon nitride phases. Based on a systematic evolutionary structure searches, we report a complete phase diagram of the C-N system at 0–300 GPa and analyze the hardest metastable structures. Surprisingly, we find that at zero pressure, the earlier proposed graphitic-C3N4 structure (P6-bar m2) is dynamically unstable, and we find the lowest-energy structuremore » based on s-triazine unit and s-heptazine unit.« less

  17. The phase diagram and hardness of carbon nitrides

    SciTech Connect (OSTI)

    Dong, Huafeng; Oganov, Artem R.; Zhu, Qiang; Zhu, Qiang; Qian, Guang-Rui

    2015-05-06

    Novel superhard materials, especially those with superior thermal and chemical stability, are needed to replace diamond. Carbon nitrides (C-N), which are likely to possess these characteristics and have even been expected to be harder than diamond, are excellent candidates. Here we report three new superhard and thermodynamically stable carbon nitride phases. Based on a systematic evolutionary structure searches, we report a complete phase diagram of the C-N system at 0–300 GPa and analyze the hardest metastable structures. Surprisingly, we find that at zero pressure, the earlier proposed graphitic-C3N4 structure (P6-bar m2) is dynamically unstable, and we find the lowest-energy structure based on s-triazine unit and s-heptazine unit.

  18. Use of silicon in liquid sintered silicon nitrides and sialons

    DOE Patents [OSTI]

    Raj, Rishi (Ithaca, NY); Baik, Sunggi (Ithaca, NY)

    1984-12-11

    This invention relates to the production of improved high density nitrogen based ceramics by liquid-phase densification of silicon nitride or a compound of silicon-nitrogen-oxygen-metal, e.g. a sialon. In the process and compositions of the invention minor amounts of finely divided silicon are employed together with the conventional liquid phase producing additives to enhance the densification of the resultant ceramic.

  19. Use of silicon in liquid sintered silicon nitrides and sialons

    DOE Patents [OSTI]

    Raj, R.; Baik, S.

    1984-12-11

    This invention relates to the production of improved high density nitrogen based ceramics by liquid-phase densification of silicon nitride or a compound of silicon-nitrogen-oxygen-metal, e.g. a sialon. In the process and compositions of the invention minor amounts of finely divided silicon are employed together with the conventional liquid phase producing additives to enhance the densification of the resultant ceramic. 4 figs.

  20. Electrically Integrated Graphene on Silicon Nitride Liquid Flow Cells for

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

    High Resolution TEM - Energy Innovation Portal Energy Storage Energy Storage Advanced Materials Advanced Materials Find More Like This Return to Search Electrically Integrated Graphene on Silicon Nitride Liquid Flow Cells for High Resolution TEM Lawrence Berkeley National Laboratory Contact LBL About This Technology Technology Marketing Summary A Berkeley Lab research team led by Paul Alivisatos and Alex Zettl has developed liquid flow cells providing unprecedented resolution and contrast in

  1. RAPID/BulkTransmission/Land Use | Open Energy Information

    Open Energy Info (EERE)

    RAPIDBulkTransmissionLand Use < RAPID | BulkTransmission Jump to: navigation, search RAPID Regulatory and Permitting Information Desktop Toolkit BETA About Bulk Transmission...

  2. RAPID/BulkTransmission/Exploration | Open Energy Information

    Open Energy Info (EERE)

    search RAPID Regulatory and Permitting Information Desktop Toolkit BETA About Bulk Transmission Geothermal Hydropower Solar Tools Contribute Contact Us RAPID Bulk Transmission ...

  3. High Heat Flux Thermoelectric Module Using Standard Bulk Material...

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

    Heat Flux Thermoelectric Module Using Standard Bulk Material High Heat Flux Thermoelectric Module Using Standard Bulk Material Presents high heat flux thermoelectric module design...

  4. RAPID/BulkTransmission/Power Plant | Open Energy Information

    Open Energy Info (EERE)

    RAPIDBulkTransmissionPower Plant < RAPID | BulkTransmission Jump to: navigation, search RAPID Regulatory and Permitting Information Desktop Toolkit BETA About Bulk...

  5. CMI Unique Facility: Bulk Combinatoric Materials Synthesis Facility...

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

    Bulk Combinatoric Materials Synthesis Facility The Bulk Combinatoric Materials Synthesis Facility is one of half a dozen unique facilities developed by the Critical Materials...

  6. RAPID/BulkTransmission/General Construction | Open Energy Information

    Open Energy Info (EERE)

    RAPIDBulkTransmissionGeneral Construction < RAPID | BulkTransmission Jump to: navigation, search RAPID Regulatory and Permitting Information Desktop Toolkit BETA About Bulk...

  7. Overview of Fraunhofer IPM Activities in High Temperature Bulk...

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

    Fraunhofer IPM Activities in High Temperature Bulk Materials and Device Development Overview of Fraunhofer IPM Activities in High Temperature Bulk Materials and Device Development ...

  8. Nanostructured High-Temperature Bulk Thermoelectric Energy Conversion...

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

    High-Temperature Bulk Thermoelectric Energy Conversion for Efficient Automotive Waste Heat Recovery Nanostructured High-Temperature Bulk Thermoelectric Energy Conversion for ...

  9. RAPID/Overview/BulkTransmission/Siting/Colorado | Open Energy...

    Open Energy Info (EERE)

    Colorado < RAPID | Overview | BulkTransmission | Siting(Redirected from RAPIDAtlasBulkTransmissionSitingColorado) Redirect page Jump to: navigation, search REDIRECT...

  10. RAPID/BulkTransmission/Water Use | Open Energy Information

    Open Energy Info (EERE)

    RAPIDBulkTransmissionWater Use < RAPID | BulkTransmission Jump to: navigation, search RAPID Regulatory and Permitting Information Desktop Toolkit BETA About Bulk Transmission...

  11. Regulatory Roadmap Workshop for Federal Bulk Transmission Regulations...

    Open Energy Info (EERE)

    for bulk transmission. Date: Tuesday, 29 July, 2014 - 09:30 - 15:30 Location: NREL Education Center Auditorium Golden, Colorado Groups: Federal Bulk Transmission Regulatory...

  12. Linux Kernel Co-Scheduling For Bulk Synchronous Parallel Applications...

    Office of Scientific and Technical Information (OSTI)

    Linux Kernel Co-Scheduling For Bulk Synchronous Parallel Applications Citation Details In-Document Search Title: Linux Kernel Co-Scheduling For Bulk Synchronous Parallel ...

  13. Micro benchtop optics by bulk silicon micromachining

    DOE Patents [OSTI]

    Lee, Abraham P. (Walnut Creek, CA); Pocha, Michael D. (Livermore, CA); McConaghy, Charles F. (Livermore, CA); Deri, Robert J. (Pleasanton, CA)

    2000-01-01

    Micromachining of bulk silicon utilizing the parallel etching characteristics of bulk silicon and integrating the parallel etch planes of silicon with silicon wafer bonding and impurity doping, enables the fabrication of on-chip optics with in situ aligned etched grooves for optical fibers, micro-lenses, photodiodes, and laser diodes. Other optical components that can be microfabricated and integrated include semi-transparent beam splitters, micro-optical scanners, pinholes, optical gratings, micro-optical filters, etc. Micromachining of bulk silicon utilizing the parallel etching characteristics thereof can be utilized to develop miniaturization of bio-instrumentation such as wavelength monitoring by fluorescence spectrometers, and other miniaturized optical systems such as Fabry-Perot interferometry for filtering of wavelengths, tunable cavity lasers, micro-holography modules, and wavelength splitters for optical communication systems.

  14. Nitridation under ammonia of high surface area vanadium aerogels

    SciTech Connect (OSTI)

    Merdrignac-Conanec, Odile [Laboratoire Verres et Ceramiques, UMR CNRS 6512, Institut de Chimie de Rennes, Universite de Rennes 1, Campus de Beaulieu, F-35042 Rennes Cedex (France)]. E-mail: odile.merdrignac@univ-rennes1.fr; El Badraoui, Khadija [Laboratoire Verres et Ceramiques, UMR CNRS 6512, Institut de Chimie de Rennes, Universite de Rennes 1, Campus de Beaulieu, F-35042 Rennes Cedex (France); L'Haridon, Paul [Laboratoire Verres et Ceramiques, UMR CNRS 6512, Institut de Chimie de Rennes, Universite de Rennes 1, Campus de Beaulieu, F-35042 Rennes Cedex (France)

    2005-01-15

    Vanadium pentoxide gels have been obtained from decavanadic acid prepared by ion exchange on a resin from ammonium metavanadate solution. The progressive removal of water by solvent exchange in supercritical conditions led to the formation of high surface area V{sub 2}O{sub 5}, 1.6H{sub 2}O aerogels. Heat treatment under ammonia has been performed on these aerogels in the 450-900 deg. C temperature range. The oxide precursors and oxynitrides have been characterized by XRD, SEM, TGA, BET. Nitridation leads to divided oxynitride powders in which the fibrous structure of the aerogel is maintained. The use of both very low heating rates and high surface area aerogel precursors allows a higher rate and a lower threshold of nitridation than those reported in previous works. By adjusting the nitridation temperature, it has been possible to prepare oxynitrides with various nitrogen enrichment and vanadium valency states. Whatever the V(O,N) composition, the oxidation of the oxynitrides in air starts between 250 and 300 deg. C. This determines their potential use as chemical gas sensors at a maximum working temperature of 250 deg. C.

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

    SciTech Connect (OSTI)

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

    2013-12-15

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

  16. One step process for producing dense aluminum nitride and composites thereof

    DOE Patents [OSTI]

    Holt, J. Birch (San Jose, CA); Kingman, Donald D. (Danville, CA); Bianchini, Gregory M. (Livermore, CA)

    1989-01-01

    A one step combustion process for the synthesis of dense aluminum nitride compositions is disclosed. The process comprises igniting pure aluminum powder in a nitrogen atmosphere at a pressure of about 1000 atmospheres or higher. The process enables the production of aluminum nitride bodies to be formed directly in a mold of any desired shape.

  17. One step process for producing dense aluminum nitride and composites thereof

    DOE Patents [OSTI]

    Holt, J.B.; Kingman, D.D.; Bianchini, G.M.

    1989-10-31

    A one step combustion process for the synthesis of dense aluminum nitride compositions is disclosed. The process comprises igniting pure aluminum powder in a nitrogen atmosphere at a pressure of about 1,000 atmospheres or higher. The process enables the production of aluminum nitride bodies to be formed directly in a mold of any desired shape.

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

    DOE Patents [OSTI]

    Raffetto, Mark (Raleigh, NC); Bharathan, Jayesh (Cary, NC); Haberern, Kevin (Cary, NC); Bergmann, Michael (Chapel Hill, NC); Emerson, David (Chapel Hill, NC); Ibbetson, James (Santa Barbara, CA); Li, Ting (Ventura, CA)

    2012-01-03

    A semiconductor based Light Emitting Device (LED) can include a p-type nitride layer and a metal ohmic contact, on the p-type nitride layer. The metal ohmic contact can have an average thickness of less than about 25 .ANG. and a specific contact resistivity less than about 10.sup.-3 ohm-cm.sup.2.

  19. Analytical and Experimental Evaluation of Joining Silicon Carbide to Silicon Carbide and Silicon Nitride to Silicon Nitride for Advanced Heat Engine Applications Phase II

    SciTech Connect (OSTI)

    Sundberg, G.J.

    1994-01-01

    Techniques were developed to produce reliable silicon nitride to silicon nitride (NCX-5101) curved joins which were used to manufacture spin test specimens as a proof of concept to simulate parts such as a simple rotor. Specimens were machined from the curved joins to measure the following properties of the join interlayer: tensile strength, shear strength, 22 C flexure strength and 1370 C flexure strength. In parallel, extensive silicon nitride tensile creep evaluation of planar butt joins provided a sufficient data base to develop models with accurate predictive capability for different geometries. Analytical models applied satisfactorily to the silicon nitride joins were Norton's Law for creep strain, a modified Norton's Law internal variable model and the Monkman-Grant relationship for failure modeling. The Theta Projection method was less successful. Attempts were also made to develop planar butt joins of siliconized silicon carbide (NT230).

  20. Ensuring a Reliable Bulk Electric System | Department of Energy

    Office of Environmental Management (EM)

    Ensuring a Reliable Bulk Electric System Ensuring a Reliable Bulk Electric System PowerPoint presentation to the Electricity Advisory Committee by David Nevitus, Senior Vice President at the North American Electric Reliability Corporation (NERC) on the reliability of the bulk power system. PDF icon Ensuring a Reliable Bulk Electric System More Documents & Publications North American Electric Reliability Corporation (NERC): Ensuring a Reliable Bulk Electric System Cooling Tower Report,

  1. Nitrided iron catalysts for the Fischer-Tropsch synthesis in the eighties

    SciTech Connect (OSTI)

    Anderson, R.B.

    1980-01-01

    Nitrided iron catalysts are active and durable and have an unusal selectivity. They do not produce significant amounts of wax, which should be advantageous in situations where gasoline is the desired product. The low yield of wax permits operation of nitrided iron in fluidized fixed-bed or entrained reactors at 230 to 255/sup 0/C. Conventional reduced iron catalysts in these reactors must be operated at about 325/sup 0/C to prevent formation of higher hydrocarbon that leads to agglomeration of the fluidized particles. At 325/sup 0/C carbon deposition and other processes leading to catalyst deterioration proceed rapidly. The yields of methane and ethane from nitrided iron are larger than desired for most purposes. Possibly promoters may be found to improve the selectivity of nitrided iron catalysts. The Bureau of Mines did not conduct a systematic catalyst development program on iron nitrides. (DP) 5 fgures, 6 tables.

  2. Iron-based alloy and nitridation treatment for PEM fuel cell bipolar plates

    DOE Patents [OSTI]

    Brady, Michael P. (Oak Ridge, TN) [Oak Ridge, TN; Yang, Bing (Oak Ridge, TN) [Oak Ridge, TN; Maziasz, Philip J. (Oak Ridge, TN) [Oak Ridge, TN

    2010-11-09

    A corrosion resistant electrically conductive component that can be used as a bipolar plate in a PEM fuel cell application is composed of an alloy substrate which has 10-30 wt. % Cr, 0.5 to 7 wt. % V, and base metal being Fe, and a continuous surface layer of chromium nitride and vanadium nitride essentially free of base metal. A oxide layer of chromium vanadium oxide can be disposed between the alloy substrate and the continuous surface nitride layer. A method to prepare the corrosion resistant electrically conductive component involves a two-step nitridization sequence by exposing the alloy to a oxygen containing gas at an elevated temperature, and subsequently exposing the alloy to an oxygen free nitrogen containing gas at an elevated temperature to yield a component where a continuous chromium nitride layer free of iron has formed at the surface.

  3. Dynamics of formation of photoresponse in a detector structure made of gallium arsenide

    SciTech Connect (OSTI)

    Ayzenshtat, G. I., E-mail: ayzen@mail.tomsknet.ru; Lelekov, M. A.; Tolbanov, O. P. [Tomsk State University (Russian Federation)

    2008-04-15

    The influence of capture effects on the characteristics of detectors of the ionizing radiation based on semi-insulating gallium arsenide is considered. Generation of nonequilibrium electrons and holes along the entire thickness of the active region was performed under illumination with an infrared light-emitting diode with a wavelength of 0.9 {mu}m. In this case, the situation emerging in the device structure under the effect of X-ray radiation or a high-energy electron beam was simulated. It is shown that the variation in the shape of the output signal with time in this case is caused by variation in the electric field profile due to the capture of holes at deep centers in gallium arsenide. An absolutely different distribution of the electric field emerges in the structure under irradiation of a semitransparent cathode of the structure with a red light-emitting diode, emission of which penetrates into the active region for mere 1 {mu}m. In this case, the transformation of the electric field is caused by the capture of electrons. Under the prolonged effect of such radiation, a space-charge-limited current mode emerges in the device.

  4. Microfabricated bulk wave acoustic bandgap device

    DOE Patents [OSTI]

    Olsson, Roy H.; El-Kady, Ihab F.; McCormick, Frederick; Fleming, James G.; Fleming, Carol

    2010-06-08

    A microfabricated bulk wave acoustic bandgap device comprises a periodic two-dimensional array of scatterers embedded within the matrix material membrane, wherein the scatterer material has a density and/or elastic constant that is different than the matrix material and wherein the periodicity of the array causes destructive interference of the acoustic wave within an acoustic bandgap. The membrane can be suspended above a substrate by an air or vacuum gap to provide acoustic isolation from the substrate. The device can be fabricated using microelectromechanical systems (MEMS) technologies. Such microfabricated bulk wave phononic bandgap devices are useful for acoustic isolation in the ultrasonic, VHF, or UHF regime (i.e., frequencies of order 1 MHz to 10 GHz and higher, and lattice constants of order 100 .mu.m or less).

  5. Microfabricated bulk wave acoustic bandgap device

    DOE Patents [OSTI]

    Olsson, Roy H. (Albuquerque, NM); El-Kady, Ihab F. (Albuquerque, NM); McCormick, Frederick (Albuquerque, NM); Fleming, James G. (Albuquerque, NM); Fleming, legal representative, Carol (Albuquerque, NM)

    2010-11-23

    A microfabricated bulk wave acoustic bandgap device comprises a periodic two-dimensional array of scatterers embedded within the matrix material membrane, wherein the scatterer material has a density and/or elastic constant that is different than the matrix material and wherein the periodicity of the array causes destructive interference of the acoustic wave within an acoustic bandgap. The membrane can be suspended above a substrate by an air or vacuum gap to provide acoustic isolation from the substrate. The device can be fabricated using microelectromechanical systems (MEMS) technologies. Such microfabricated bulk wave phononic bandgap devices are useful for acoustic isolation in the ultrasonic, VHF, or UHF regime (i.e., frequencies of order 1 MHz to 10 GHz and higher, and lattice constants of order 100 .mu.m or less).

  6. Modeling direct interband tunneling. I. Bulk semiconductors

    SciTech Connect (OSTI)

    Pan, Andrew; Chui, Chi On

    2014-08-07

    Interband tunneling is frequently studied using the semiclassical Kane model, despite uncertainty about its validity. Revisiting the physical basis of this formula, we find that it neglects coupling to other bands and underestimates transverse tunneling. As a result, significant errors can arise at low and high fields for small and large gap materials, respectively. We derive a simple multiband tunneling model to correct these defects analytically without arbitrary parameters. Through extensive comparison with band structure and quantum transport calculations for bulk InGaAs, InAs, and InSb, we probe the accuracy of the Kane and multiband formulas and establish the superiority of the latter. We also show that the nonlocal average electric field should be used when applying either of these models to nonuniform potentials. Our findings are important for efficient analysis and simulation of bulk semiconductor devices involving tunneling.

  7. DEMONSTRATION BULK VITRIFICATION SYSTEM (DBVS) EXTERNAL REVIEW

    SciTech Connect (OSTI)

    HONEYMAN, J.O.

    2007-02-08

    The Hanford mission to retrieve and immobilize 53 million gallons of radioactive waste from 177 underground storage tanks will be accomplished using a combination of processing by the waste treatment plant currently under construction, and a supplemental treatment that would process low-activity waste. Under consideration for this treatment is bulk vitrification, a versatile joule-heated melter technology which could be deployed in the tank farms. The Department proposes to demonstrate this technology under a Research, Development and Demonstration (RD and D) permit issued by the Washington State Department of Ecology using both non-radioactive simulant and blends of actual tank waste. From the demonstration program, data would be obtained on cost and technical performance to enable a decision on the potential use of bulk vitrification as the supplemental treatment technology for Hanford. An independent review by sixteen subject matter experts was conducted to assure that the technical basis of the demonstration facility design would be adequate to meet the objectives of the Demonstration Bulk Vitrification System (DBVS) program. This review explored all aspects of the program, including flowsheet chemistry, project risk, vitrification, equipment design and nuclear safety, and was carried out at a time when issues can be identified and corrected. This paper describes the mission need, review approach, technical recommendations and follow-on activities for the DBVS program.

  8. Hydrogen isotope separation utilizing bulk getters

    DOE Patents [OSTI]

    Knize, Randall J. (Los Angeles, CA); Cecchi, Joseph L. (Lawrenceville, NJ)

    1990-01-01

    Tritium and deuterium are separated from a gaseous mixture thereof, derived from a nuclear fusion reactor or some other source, by providing a casing with a bulk getter therein for absorbing the gaseous mixture to produce an initial loading of the getter, partially desorbing the getter to produce a desorbed mixture which is tritium-enriched, pumping the desorbed mixture into a separate container, the remaining gaseous loading in the getter being deuterium-enriched, desorbing the getter to a substantially greater extent to produce a deuterium-enriched gaseous mixture, and removing the deuterium-enriched mixture into another container. The bulk getter may comprise a zirconium-aluminum alloy, or a zirconium-vanadium-iron alloy. The partial desorption may reduce the loading by approximately fifty percent. The basic procedure may be extended to produce a multistage isotope separator, including at least one additional bulk getter into which the tritium-enriched mixture is absorbed. The second getter is then partially desorbed to produce a desorbed mixture which is further tritium-enriched. The last-mentioned mixture is then removed from the container for the second getter, which is then desorbed to a substantially greater extent to produce a desorbed mixture which is deuterium-enriched. The last-mentioned mixture is then removed so that the cycle can be continued and repeated. The method of isotope separation is also applicable to other hydrogen isotopes, in that the method can be employed for separating either deuterium or tritium from normal hydrogen.

  9. Hydrogen isotope separation utilizing bulk getters

    DOE Patents [OSTI]

    Knize, Randall J. (Los Angeles, CA); Cecchi, Joseph L. (Lawrenceville, NJ)

    1991-01-01

    Tritium and deuterium are separated from a gaseous mixture thereof, derived from a nuclear fusion reactor or some other source, by providing a casing with a bulk getter therein for absorbing the gaseous mixture to produce an initial loading of the getter, partially desorbing the getter to produce a desorbed mixture which is tritium-enriched, pumping the desorbed mixture into a separate container, the remaining gaseous loading in the getter being deuterium-enriched, desorbing the getter to a substantially greater extent to produce a deuterium-enriched gaseous mixture, and removing the deuterium-enriched mixture into another container. The bulk getter may comprise a zirconium-aluminum alloy, or a zirconium-vanadium-iron alloy. The partial desorption may reduce the loading by approximately fifty percent. The basic procedure may be extended to produce a multistage isotope separator, including at least one additional bulk getter into which the tritium-enriched mixture is absorbed. The second getter is then partially desorbed to produce a desorbed mixture which is further tritium-enriched. The last-mentioned mixture is then removed from the container for the second getter, which is then desorbed to a substantially greater extent to produce a desorbed mixture which is deuterium-enriched. The last-mentioned mixture is then removed so that the cycle can be continued and repeated. The method of isotope separation is also applicable to other hydrogen isotopes, in that the method can be employed for separating either deuterium or tritium from normal hydrogen.

  10. Hydrogen isotope separation utilizing bulk getters

    DOE Patents [OSTI]

    Knize, R.J.; Cecchi, J.L.

    1991-08-20

    Tritium and deuterium are separated from a gaseous mixture thereof, derived from a nuclear fusion reactor or some other source, by providing a casing with a bulk getter therein for absorbing the gaseous mixture to produce an initial loading of the getter, partially desorbing the getter to produce a desorbed mixture which is tritium-enriched, pumping the desorbed mixture into a separate container, the remaining gaseous loading in the getter being deuterium-enriched, desorbing the getter to a substantially greater extent to produce a deuterium-enriched gaseous mixture, and removing the deuterium-enriched mixture into another container. The bulk getter may comprise a zirconium-aluminum alloy, or a zirconium-vanadium-iron alloy. The partial desorption may reduce the loading by approximately fifty percent. The basic procedure may be extended to produce a multistage isotope separator, including at least one additional bulk getter into which the tritium-enriched mixture is absorbed. The second getter is then partially desorbed to produce a desorbed mixture which is further tritium-enriched. The last-mentioned mixture is then removed from the container for the second getter, which is then desorbed to a substantially greater extent to produce a desorbed mixture which is deuterium-enriched. The last-mentioned mixture is then removed so that the cycle can be continued and repeated. The method of isotope separation is also applicable to other hydrogen isotopes, in that the method can be employed for separating either deuterium or tritium from normal hydrogen. 4 figures.

  11. Method of nitriding niobium to form a superconducting surface

    DOE Patents [OSTI]

    Kelley, Michael J.; Klopf, John Michael; Singaravelu, Senthilaraja

    2014-08-19

    A method of forming a delta niobium nitride .delta.-NbN layer on the surface of a niobium object including cleaning the surface of the niobium object; providing a treatment chamber; placing the niobium object in the treatment chamber; evacuating the chamber; passing pure nitrogen into the treatment chamber; focusing a laser spot on the niobium object; delivering laser fluences at the laser spot until the surface of the niobium object reaches above its boiling temperature; and rastering the laser spot over the surface of the niobium object.

  12. Boron nitride nanosheets as oxygen-atom corrosion protective coatings

    SciTech Connect (OSTI)

    Yi, Min; Shen, Zhigang; Zhao, Xiaohu; Liang, Shuaishuai; Liu, Lei

    2014-04-07

    The research of two-dimensional nanomaterials for anticorrosion applications is just recently burgeoning. Herein, we demonstrate the boron nitride nanosheets (BNNSs) coatings for protecting polymer from oxygen-atom corrosion. High-quality BNNSs, which are produced by an effective fluid dynamics method with multiple exfoliation mechanisms, can be assembled into coatings with controlled thickness by vacuum filtration. After exposed in atom oxygen, the naked polymer is severely corroded with remarkable mass loss, while the BNNSs-coated polymer remains intact. Barrier and bonding effects of the BNNSs are responsible for the coating's protective performance. These preliminary yet reproducible results pave a way for resisting oxygen-atom corrosion.

  13. Preparation of superhydrophobic nanodiamond and cubic boron nitride films

    SciTech Connect (OSTI)

    Zhou, Y. B.; Liu, W. M.; Wang, P. F.; Yang, Y.; Ye, Q.; He, B.; Pan, X. J.; Zhang, W. J.; Bello, I.; Lee, S. T.; Zou, Y. S.

    2010-09-27

    Superhydrophobic surfaces were achieved on the hardest and the second hardest materials, diamond and cubic boron nitride (cBN) films. Various surface nanostructures of nanocrystalline diamond (ND) and cBN films were constructed by carrying out bias-assisted reactive ion etching in hydrogen/argon plasmas; and it is shown that surface nanostructuring may enhance dramatically the hydrophobicity of ND and cBN films. Together with surface fluorination, superhydrophobic ND and cBN surfaces with a contact angle greater than 150 deg. and a sliding angle smaller than 10 deg. were demonstrated. The origin of hydrophobicity enhancement is discussed based on the Cassie model.

  14. Field emission characteristics from graphene on hexagonal boron nitride

    SciTech Connect (OSTI)

    Yamada, Takatoshi, E-mail: takatoshi-yamada@aist.go.jp [National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565 (Japan); Masuzawa, Tomoaki; Ebisudani, Taishi; Okano, Ken [International Christian University, 3-10-2 Osawa, Mitaka, Tokyo 181-8585 (Japan); Taniguchi, Takashi [National Institute for Material Science (NIMS), 1-1-1 Namiki, Tsukuba 305-0044 (Japan)

    2014-06-02

    An attempt has been made to utilize uniquely high electron mobility of graphene on hexagonal boron nitride (h-BN) to electron emitter. The field emission property of graphene/h-BN/Si structure has shown enhanced threshold voltage and emission current, both of which are key to develop novel vacuum nanoelectronics devices. The field emission property was discussed along with the electronic structure of graphene investigated by Fowler-Nordheim plot and ultraviolet photoelectron spectroscopy. The result suggested that transferring graphene on h-BN modified its work function, which changed field emission mechanism. Our report opens up a possibility of graphene-based vacuum nanoelectronics devices with tuned work function.

  15. Metal Nitride Catalysts to Enhance Hydrogen Evolution Reactions - Energy

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

    Innovation Portal Solar Photovoltaic Solar Photovoltaic Hydrogen and Fuel Cell Hydrogen and Fuel Cell Find More Like This Return to Search Metal Nitride Catalysts to Enhance Hydrogen Evolution Reactions Brookhaven National Laboratory Contact BNL About This Technology TEM image of catalyst ink comprised of Co<sub>0.6</sub>Mo<sub>1.4</sub>N<sub>2</sub> dispersed on carbon black TEM image of catalyst ink comprised of Co0.6Mo1.4N2 dispersed on carbon black

  16. Morphological development and oxidation mechanisms of aluminum nitride whiskers

    SciTech Connect (OSTI)

    Hou Xinmei; Yue Changsheng; Kumar Singh, Ankit; Zhang Mei; Chou Kuochih

    2010-04-15

    Hexagonal aluminum nitride (AlN) whiskers have been synthesized at 1873 K under a flowing nitrogen atmosphere. The synthesized whiskers are long straight filaments with diameters between 1 and 5 {mu}m and length in the cm range. In order to investigate its 'oxidation resistance', a series of experiments have been performed. The oxidation behavior was quite different in the experimental temperature range assigned, which can be attributed to the kinetic factor and the morphological development during oxidation process. It was chemical controlled at lower temperature while both chemical reaction and diffusion controlled at medium temperature. Further accelerating of temperature to 1473 K, AlN whiskers was peeled into smaller parts, which increased the oxidation rate and hence showed powder-like oxidation behavior. Our new kinetic theory has been applied to study the oxidation behavior of AlN whiskers. The comparison of the experimental data with the theoretical ones validates the applicability of the new model. - Hexagonal aluminum nitride (AlN) whiskers have been synthesized at 1873 K under a flowing nitrogen atmosphere. The synthesized whiskers are long straight filaments with diameters between 1 and 5 {mu}m and length in the cm range.

  17. Transport properties of ultrathin black phosphorus on hexagonal boron nitride

    SciTech Connect (OSTI)

    Doganov, Rostislav A.; zyilmaz, Barbaros; Koenig, Steven P.; Yeo, Yuting; Watanabe, Kenji; Taniguchi, Takashi

    2015-02-23

    Ultrathin black phosphorus, or phosphorene, is a two-dimensional material that allows both high carrier mobility and large on/off ratios. Similar to other atomic crystals, like graphene or layered transition metal dichalcogenides, the transport behavior of few-layer black phosphorus is expected to be affected by the underlying substrate. The properties of black phosphorus have so far been studied on the widely utilized SiO{sub 2} substrate. Here, we characterize few-layer black phosphorus field effect transistors on hexagonal boron nitridean atomically smooth and charge trap-free substrate. We measure the temperature dependence of the field effect mobility for both holes and electrons and explain the observed behavior in terms of charged impurity limited transport. We find that in-situ vacuum annealing at 400?K removes the p-doping of few-layer black phosphorus on both boron nitride and SiO{sub 2} substrates and reduces the hysteresis at room temperature.

  18. Improving the bulk data transfer experience

    SciTech Connect (OSTI)

    Guok, Chin; Guok, Chin; Lee, Jason R.; Berket, Karlo

    2008-05-07

    Scientific computations and collaborations increasingly rely on the network to provide high-speed data transfer, dissemination of results, access to instruments, support for computational steering, etc. The Energy Sciences Network is establishing a science data network to provide user driven bandwidth allocation. In a shared network environment, some reservations may not be granted due to the lack of available bandwidth on any single path. In many cases, the available bandwidth across multiple paths would be sufficient to grant the reservation. In this paper we investigate how to utilize the available bandwidth across multiple paths in the case of bulk data transfer.

  19. Towards bulk based preconditioning for quantum dotcomputations

    SciTech Connect (OSTI)

    Dongarra, Jack; Langou, Julien; Tomov, Stanimire; Channing,Andrew; Marques, Osni; Vomel, Christof; Wang, Lin-Wang

    2006-05-25

    This article describes how to accelerate the convergence of Preconditioned Conjugate Gradient (PCG) type eigensolvers for the computation of several states around the band gap of colloidal quantum dots. Our new approach uses the Hamiltonian from the bulk materials constituent for the quantum dot to design an efficient preconditioner for the folded spectrum PCG method. The technique described shows promising results when applied to CdSe quantum dot model problems. We show a decrease in the number of iteration steps by at least a factor of 4 compared to the previously used diagonal preconditioner.

  20. Tunneling characteristics in chemical vapor deposited graphenehexagonal boron nitridegraphene junctions

    SciTech Connect (OSTI)

    Roy, T.; Hesabi, Z. R.; Joiner, C. A.; Vogel, E. M. [School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive, Atlanta, Georgia 30332 (United States); Liu, L.; Gu, G. [Department of Electrical Engineering and Computer Science, University of Tennessee, 1520 Middle Drive, Knoxville, Tennessee 37996 (United States); Barrera, S. de la; Feenstra, R. M. [Department of Physics, Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, Pennsylvania 15213 (United States); Chakrabarti, B. [School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive, Atlanta, Georgia 30332 (United States); Department of Materials Science and Engineering, University of Texas at Dallas, 800 West Campbell Rd., Richardson, Texas 75080 (United States)

    2014-03-24

    Large area chemical vapor deposited graphene and hexagonal boron nitride was used to fabricate graphenehexagonal boron nitridegraphene symmetric field effect transistors. Gate control of the tunneling characteristics is observed similar to previously reported results for exfoliated graphenehexagonal boron nitridegraphene devices. Density-of-states features are observed in the tunneling characteristics of the devices, although without large resonant peaks that would arise from lateral momentum conservation. The lack of distinct resonant behavior is attributed to disorder in the devices, and a possible source of the disorder is discussed.

  1. The influence of molecular orientation on organic bulk heterojunction...

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

    on organic bulk heterojunction solar cells The influence of molecular orientation on organic bulk heterojunction solar cells Print Monday, 28 April 2014 09:03 Work done on ALS...

  2. Boundary Entropy Can Increase Under Bulk RG Flow (Journal Article...

    Office of Scientific and Technical Information (OSTI)

    Boundary Entropy Can Increase Under Bulk RG Flow Citation Details In-Document Search Title: Boundary Entropy Can Increase Under Bulk RG Flow You are accessing a document from...

  3. Analysis of gallium arsenide deposition in a horizontal chemical vapor deposition reactor using massively parallel computations

    SciTech Connect (OSTI)

    Salinger, A.G.; Shadid, J.N.; Hutchinson, S.A.

    1998-01-01

    A numerical analysis of the deposition of gallium from trimethylgallium (TMG) and arsine in a horizontal CVD reactor with tilted susceptor and a three inch diameter rotating substrate is performed. The three-dimensional model includes complete coupling between fluid mechanics, heat transfer, and species transport, and is solved using an unstructured finite element discretization on a massively parallel computer. The effects of three operating parameters (the disk rotation rate, inlet TMG fraction, and inlet velocity) and two design parameters (the tilt angle of the reactor base and the reactor width) on the growth rate and uniformity are presented. The nonlinear dependence of the growth rate uniformity on the key operating parameters is discussed in detail. Efficient and robust algorithms for massively parallel reacting flow simulations, as incorporated into our analysis code MPSalsa, make detailed analysis of this complicated system feasible.

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

    SciTech Connect (OSTI)

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

    2014-06-09

    The origin of the deep subgap states in amorphous indium gallium zinc oxide (a-IGZO), whether intrinsic to the amorphous structure or not, has serious implications for the development of p-type transparent amorphous oxide semiconductors. We report that the deep subgap feature in a-IGZO originates from local variations in the oxygen coordination and not from oxygen vacancies. This is shown by the positive correlation between oxygen composition and subgap intensity as observed with X-ray photoelectron spectroscopy. We also demonstrate that the subgap feature is not intrinsic to the amorphous phase because the deep subgap feature can be removed by low-temperature annealing in a reducing environment. Atomistic calculations of a-IGZO reveal that the subgap state originates from certain oxygen environments associated with the disorder. Specifically, the subgap states originate from oxygen environments with a lower coordination number and/or a larger metal-oxygen separation.

  5. Outdoor Performance of a Thin-Film Gallium-Arsenide Photovoltaic Module

    SciTech Connect (OSTI)

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

    2013-06-01

    We deployed a 855 cm2 thin-film, single-junction gallium arsenide (GaAs) photovoltaic (PV) module outdoors. Due to its fundamentally different cell technology compared to silicon (Si), the module responds differently to outdoor conditions. On average during the test, the GaAs module produced more power when its temperature was higher. We show that its maximum-power temperature coefficient, while actually negative, is several times smaller in magnitude than that of a Si module used for comparison. The positive correlation of power with temperature in GaAs is due to temperature-correlated changes in the incident spectrum. We show that a simple correction based on precipitable water vapor (PWV) brings the photocurrent temperature coefficient into agreement with that measured by other methods and predicted by theory. The low operating temperature and small temperature coefficient of GaAs give it an energy production advantage in warm weather.

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

    SciTech Connect (OSTI)

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

    2014-03-05

    Gallium arsenide (GaAs) nanowires were grown vertically on GaAs(111)B substrate by gold-assisted using metal-organic chemical vapour deposition. Field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and conductivity atomic force microscopy (CAFM) analysis were carried out to investigate the effects of V/III ratio on structural properties and current-voltage changes in the wires. Results show that GaAs NWs grow preferably in the wurtzite crystal structure than zinc blende crystal structure with increasing V/III ratio. Additionally, CAFM studies have revealed that zincblende nanowires indicate ohmic characteristic compared to oscillation current occurred for wurtzite structures. The GaAs NWs with high quality structures are needed in solar cells technology for trapping energy that directly converts of sunlight into electricity with maximum capacity.

  7. Achieving large linear elasticity and high strength in bulk nanocompsite

    Office of Scientific and Technical Information (OSTI)

    via synergistic effect (Journal Article) | DOE PAGES DOE PAGES Search Results Accepted Manuscript: Achieving large linear elasticity and high strength in bulk nanocompsite via synergistic effect Title: Achieving large linear elasticity and high strength in bulk nanocompsite via synergistic effect Elastic strain in bulk metallic materials is usually limited to only a fraction of 1%. Developing bulk metallic materials showing large linear elasticity and high strength has proven to be

  8. Substantial bulk photovoltaic effect enhancement via nanolayering

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

    Wang, Fenggong; Young, Steve M.; Zheng, Fan; Grinberg, Ilya; Rappe, Andrew M.

    2016-01-21

    Spontaneous polarization and inversion symmetry breaking in ferroelectric materials lead to their use as photovoltaic devices. However, further advancement of their applications are hindered by the paucity of ways of reducing bandgaps and enhancing photocurrent. By unravelling the correlation between ferroelectric materials’ responses to solar irradiation and their local structure and electric polarization landscapes, here we show from first principles that substantial bulk photovoltaic effect enhancement can be achieved by nanolayering PbTiO3 with nickel ions and oxygen vacancies ((PbNiO2)x(PbTiO3)1–x). The enhancement of the total photocurrent for different spacings between the Ni-containing layers can be as high as 43 times duemore » to a smaller bandgap and photocurrent direction alignment for all absorption energies. This is due to the electrostatic effect that arises from nanolayering. Lastly, this opens up the possibility for control of the bulk photovoltaic effect in ferroelectric materials by nanoscale engineering of their structure and composition.« less

  9. Commercialization of Bulk Thermoelectric Materials for Power Generation |

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

    Department of Energy Commercialization of Bulk Thermoelectric Materials for Power Generation Commercialization of Bulk Thermoelectric Materials for Power Generation Critical aspects of technology commercialization of preproduction high performance thermoelectric materials available for device developers, data analysis, and future plans are discussed PDF icon kossakovski.pdf More Documents & Publications Commercialization of Bulk Thermoelectric Materials for Power Generation Fact #897:

  10. Correlation Between Structure and Thermoelectric Properties of Bulk High

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

    Performance Materials for Energy Conversion | Department of Energy Correlation Between Structure and Thermoelectric Properties of Bulk High Performance Materials for Energy Conversion Correlation Between Structure and Thermoelectric Properties of Bulk High Performance Materials for Energy Conversion Rapid solidified precursor converted into crystalline bulks under pressure produced thermoelectric materials of nano-sized grains with strongly coupled grain boundaries, achieving reduced lattice

  11. Method of nitriding, carburizing, or oxidizing refractory metal articles using microwaves

    DOE Patents [OSTI]

    Holcombe, Cressie E. (Knoxville, TN); Dykes, Norman L. (Oak Ridge, TN); Tiegs, Terry N. (Lenoir City, TN)

    1992-01-01

    A method of nitriding an article of refractory-nitride-forming metal or metalloids. A consolidated metal or metalloid article is placed inside a microwave oven and nitrogen containing gas is introduced into the microwave oven. The metal or metalloid article is heated to a temperature sufficient to react the metal or metalloid with the nitrogen by applying a microwave energy within the microwave oven. The metal or metalloid article is maintained at that temperature for a period of time sufficient to convert the article of metal or metalloid to an article of refractory nitride. in addition, a method of applying a coating, such as a coating of an oxide, a carbide, or a carbo-nitride, to an article of metal or metalloid by microwave heating.

  12. Method of nitriding, carburizing, or oxidizing refractory metal articles using microwaves

    DOE Patents [OSTI]

    Holcombe, C.E.; Dykes, N.L.; Tiegs, T.N.

    1992-10-13

    A method of nitriding an article of refractory-nitride-forming metal or metalloids. A consolidated metal or metalloid article is placed inside a microwave oven and nitrogen containing gas is introduced into the microwave oven. The metal or metalloid article is heated to a temperature sufficient to react the metal or metalloid with the nitrogen by applying a microwave energy within the microwave oven. The metal or metalloid article is maintained at that temperature for a period of time sufficient to convert the article of metal or metalloid to an article of refractory nitride. in addition, a method of applying a coating, such as a coating of an oxide, a carbide, or a carbo-nitride, to an article of metal or metalloid by microwave heating.

  13. Sandia Energy - III-Nitride core-shell nanowire arrayed solar...

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

    for other III-nitride devices such as light-emitting diodes (LEDs). Abstract: A solar cell based on a hybrid nanowire-film architecture consisting of a vertically aligned...

  14. Aluminum nitride transitional layer for reducing dislocation density and cracking of AIGan epitaxial films

    DOE Patents [OSTI]

    Allerman, Andrew A. (Tijeras, NM); Crawford, Mary H. (Albuquerque, NM); Koleske, Daniel D. (Albuquerque, NM); Lee, Stephen R. (Albuquerque, NM)

    2011-03-29

    A denticulated Group III nitride structure that is useful for growing Al.sub.xGa.sub.1-xN to greater thicknesses without cracking and with a greatly reduced threading dislocation (TD) density.

  15. Method of enhancing the wettability of boron nitride for use as an electrochemical cell separator

    DOE Patents [OSTI]

    McCoy, L.R.

    1981-01-23

    A felt or other fabric of boron nitride suitable for use as an interelectrode separator within an electrochemical cell is wetted with a solution containing a thermally decomposable organic salt of an alkaline earth metal. An aqueous solution of magnesium acetate is the preferred solution for this purpose. After wetting the boron nitride, the solution is dried by heating at a sufficiently low temperature to prevent rapid boiling and the creation of voids within the separator. The dried material is then calcined at an elevated temperature in excess of 400/sup 0/C to provide a coating of an oxide of magnesium on the surface of the boron nitride fibers. A fabric or felt of boron nitride treated in this manner is easily wetted by molten electrolytic salts, such as the alkali metal halides or alkaline earth metal halides, that are used in high temperature, secondary electrochemical cells.

  16. Method of enhancing the wettability of boron nitride for use as an electrochemical cell separator

    DOE Patents [OSTI]

    McCoy, Lowell R. (Woodland Hills, CA)

    1982-01-01

    A felt or other fabric of boron nitride suitable for use as an interelecte separator within an electrochemical cell is wetted with a solution containing a thermally decomposable organic salt of an alkaline earth metal. An aqueous solution of magnesium acetate is the preferred solution for this purpose. After wetting the boron nitride, the solution is dried by heating at a sufficiently low temperature to prevent rapid boiling and the creation of voids within the separator. The dried material is then calcined at an elevated temperature in excess of 400.degree. C. to provide a coating of an oxide of magnesium on the surface of the boron nitride fibers. A fabric or felt of boron nitride treated in this manner is easily wetted by molten electrolytic salts, such as the alkali metal halides or alkaline earth metal halides, that are used in high temperature, secondary electrochemical cells.

  17. Precursors in the preparation of transition metal nitrides and transition metal carbonitrides and their reaction intermediates

    DOE Patents [OSTI]

    Maya, Leon (Oak Ridge, TN)

    1991-01-01

    A process for making ammonolytic precursors to nitride and carbonitride ceramics. Extreme reaction conditions are not required and the precursor is a powder-like substance that produces ceramics of improved purity and morphology upon pyrolysis.

  18. Process for preparing transition metal nitrides and transition metal carbonitrides and their reaction intermediates

    DOE Patents [OSTI]

    Maya, Leon (Oak Ridge, TN)

    1988-05-24

    A process for making ammonolytic precursors to nitride and carbonitride ceramics. Extreme reaction conditions are not required and the precursor is a powder-like substance that produces ceramics of improved purity and morphology upon pyrolysis.

  19. The electron beam hole drilling of silicon nitride thin films

    SciTech Connect (OSTI)

    Howitt, D. G.; Chen, S. J.; Gierhart, B. C.; Smith, R. L.; Collins, S. D.

    2008-01-15

    The mechanism by which an intense electron beam can produce holes in thin films of silicon nitride has been investigated using a combination of in situ electron energy loss spectrometry and electron microscopy imaging. A brief review of electron beam interactions that lead to material loss in different materials is also presented. The loss of nitrogen and silicon decreases with decreasing beam energy and although still observable at a beam energy of 150 keV ceases completely at 120 keV. The linear behavior of the loss rate coupled with the energy dependency indicates that the process is primarily one of direct displacement, involving the sputtering of atoms from the back surface of the specimen with the rate controlling mechanism being the loss of nitrogen.

  20. Spectroscopic ellipsometry characterization of thin-film silicon nitride

    SciTech Connect (OSTI)

    Jellison, G.E. Jr.; Modine, F.A.; Doshi, P.; Rohatgi, A.

    1997-05-01

    We have measured and analyzed the optical characteristics of a series of silicon nitride thin films prepared by plasma-enhanced chemical vapor deposition on silicon substrates for photovoltaic applications. Spectroscopic ellipsometry measurements were made by using a two-channel spectroscopic polarization modulator ellipsometer that measures N, S, and C data simultaneously. The data were fit to a model consisting of air / roughness / SiN / crystalline silicon. The roughness was modeled using the Bruggeman effective medium approximation, assuming 50% SiN, 50% voids. The optical functions of the SiN film were parameterized using a model by Jellison and Modine. All the {Chi}{sup 2} are near 1, demonstrating that this model works extremely well for all SiN films. The measured dielectric functions were used to make optimized SiN antireflection coatings for crystalline silicon solar cells.

  1. DEVELOPMENT OF TITANIUM NITRIDE COATING FOR SNS RING VACUUM CHAMBERS.

    SciTech Connect (OSTI)

    HE,P.; HSEUH,H.C.; MAPES,M.; TODD,R.; WEISS,D.

    2001-06-18

    The inner surface of the ring vacuum chambers of the US Spallation Neutron Source (SNS) will be coated with {approximately}100 nm of Titanium Nitride (TiN). This is to minimize the secondary electron yield (SEY) from the chamber wall, and thus avoid the so-called e-p instability caused by electron multipacting as observed in a few high-intensity proton storage rings. Both DC sputtering and DC-magnetron sputtering were conducted in a test chamber of relevant geometry to SNS ring vacuum chambers. Auger Electron Spectroscopy (AES) and Rutherford Back Scattering (RBS) were used to analyze the coatings for thickness, stoichiometry and impurity. Excellent results were obtained with magnetron sputtering. The development of the parameters for the coating process and the surface analysis results are presented.

  2. Methods for improved growth of group III nitride semiconductor compounds

    DOE Patents [OSTI]

    Melnik, Yuriy; Chen, Lu; Kojiri, Hidehiro

    2015-03-17

    Methods are disclosed for growing group III-nitride semiconductor compounds with advanced buffer layer technique. In an embodiment, a method includes providing a suitable substrate in a processing chamber of a hydride vapor phase epitaxy processing system. The method includes forming an AlN buffer layer by flowing an ammonia gas into a growth zone of the processing chamber, flowing an aluminum halide containing precursor to the growth zone and at the same time flowing additional hydrogen halide or halogen gas into the growth zone of the processing chamber. The additional hydrogen halide or halogen gas that is flowed into the growth zone during buffer layer deposition suppresses homogeneous AlN particle formation. The hydrogen halide or halogen gas may continue flowing for a time period while the flow of the aluminum halide containing precursor is turned off.

  3. Impurity-induced disorder in III-nitride materials and devices

    DOE Patents [OSTI]

    Wierer, Jr., Jonathan J; Allerman, Andrew A

    2014-11-25

    A method for impurity-induced disordering in III-nitride materials comprises growing a III-nitride heterostructure at a growth temperature and doping the heterostructure layers with a dopant during or after the growth of the heterostructure and post-growth annealing of the heterostructure. The post-growth annealing temperature can be sufficiently high to induce disorder of the heterostructure layer interfaces.

  4. Design of defect spins in piezoelectric aluminum nitride for solid-state

    Office of Scientific and Technical Information (OSTI)

    hybrid quantum technologies (Journal Article) | SciTech Connect Design of defect spins in piezoelectric aluminum nitride for solid-state hybrid quantum technologies Citation Details In-Document Search Title: Design of defect spins in piezoelectric aluminum nitride for solid-state hybrid quantum technologies Spin defects in wide-band gap semiconductors are promising systems for the realization of quantum bits, or qubits, in solid-state environments. To date, defect qubits have only been

  5. Advanced surface plasma nitriding for development of corrosion resistant and accident tolerant fuel cladding

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

    surface plasma nitriding for development of corrosion resistant and accident tolerant fuel cladding PI: Lin Shao, Texas A&M University Collaborators: Don A. Lucca - Oklahoma State University, Michael P. Short - Massachusetts Institute of Technology, Frank Garner - Texas A&M University Program: Nuclear Energy Enabling Technologies Presented by Elizabeth Castanon, Ph.D candidate in Nuclear Eng., Texas A&M University This project aims to develop a new plasma nitriding technique which is

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

    DOE Patents [OSTI]

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

    1999-02-16

    A photovoltaic cell exhibiting an overall conversion efficiency of 13.6% is prepared from a copper-indium-gallium-diselenide precursor thin film. The film is fabricated by first simultaneously electrodepositing copper, indium, gallium, and selenium onto a glass/molybdenum substrate (12/14). The electrodeposition voltage is a high frequency AC voltage superimposed upon a DC voltage to improve the morphology and growth rate of the film. The electrodeposition is followed by physical vapor deposition to adjust the final stoichiometry of the thin film to approximately Cu(In.sub.1-n Ga.sub.x)Se.sub.2, with the ratio of Ga/(In+Ga) being approximately 0.39.

  7. Bulk amorphous steels based on Fe alloys

    DOE Patents [OSTI]

    Lu, ZhaoPing; Liu, Chain T.

    2006-05-30

    A bulk amorphous alloy has the approximate composition: Fe.sub.(100-a-b-c-d-e)Y.sub.aMn.sub.bT.sub.cM.sub.dX.sub.e wherein: T includes at least one of the group consisting of: Ni, Cu, Cr and Co; M includes at least one of the group consisting of W, Mo, Nb, Ta, Al and Ti; X includes at least one of the group consisting of Co, Ni and Cr; a is an atomic percentage, and a<5; b is an atomic percentage, and b.ltoreq.25; c is an atomic percentage, and c.ltoreq.25; d is an atomic percentage, and d.ltoreq.25; and e is an atomic percentage, and 5.ltoreq.e.ltoreq.30.

  8. Organic hybrid planar-nanocrystalline bulk heterojunctions

    DOE Patents [OSTI]

    Forrest, Stephen R.; Yang, Fan

    2013-04-09

    A photosensitive optoelectronic device having an improved hybrid planar bulk heterojunction includes a plurality of photoconductive materials disposed between the anode and the cathode. The photoconductive materials include a first continuous layer of donor material and a second continuous layer of acceptor material. A first network of donor material or materials extends from the first continuous layer toward the second continuous layer, providing continuous pathways for conduction of holes to the first continuous layer. A second network of acceptor material or materials extends from the second continuous layer toward the first continuous layer, providing continuous pathways for conduction of electrons to the second continuous layer. The first network and the second network are interlaced with each other. At least one other photoconductive material is interspersed between the interlaced networks. This other photoconductive material or materials has an absorption spectra different from the donor and acceptor materials.

  9. DEPLOYMENT OF THE BULK TRITIUM SHIPPING PACKAGE

    SciTech Connect (OSTI)

    Blanton, P.

    2013-10-10

    A new Bulk Tritium Shipping Package (BTSP) was designed by the Savannah River National Laboratory to be a replacement for a package that has been used to ship tritium in a variety of content configurations and forms since the early 1970s. The BTSP was certified by the National Nuclear Safety Administration in 2011 for shipments of up to 150 grams of Tritium. Thirty packages were procured and are being delivered to various DOE sites for operational use. This paper summarizes the design features of the BTSP, as well as associated engineered material improvements. Fabrication challenges encountered during production are discussed as well as fielding requirements. Current approved tritium content forms (gas and tritium hydrides), are reviewed, as well as, a new content, tritium contaminated water on molecular sieves. Issues associated with gas generation will also be discussed.

  10. Rotary adsorbers for continuous bulk separations

    DOE Patents [OSTI]

    Baker, Frederick S. (Oak Ridge, TN)

    2011-11-08

    A rotary adsorber for continuous bulk separations is disclosed. The rotary adsorber includes an adsorption zone in fluid communication with an influent adsorption fluid stream, and a desorption zone in fluid communication with a desorption fluid stream. The fluid streams may be gas streams or liquid streams. The rotary adsorber includes one or more adsorption blocks including adsorbent structure(s). The adsorbent structure adsorbs the target species that is to be separated from the influent fluid stream. The apparatus includes a rotary wheel for moving each adsorption block through the adsorption zone and the desorption zone. A desorption circuit passes an electrical current through the adsorbent structure in the desorption zone to desorb the species from the adsorbent structure. The adsorbent structure may include porous activated carbon fibers aligned with their longitudinal axis essentially parallel to the flow direction of the desorption fluid stream. The adsorbent structure may be an inherently electrically-conductive honeycomb structure.

  11. Organic hybrid planar-nanocrystalline bulk heterojunctions

    DOE Patents [OSTI]

    Forrest, Stephen R. (Ann Arbor, MI); Yang, Fan (Piscataway, NJ)

    2011-03-01

    A photosensitive optoelectronic device having an improved hybrid planar bulk heterojunction includes a plurality of photoconductive materials disposed between the anode and the cathode. The photoconductive materials include a first continuous layer of donor material and a second continuous layer of acceptor material. A first network of donor material or materials extends from the first continuous layer toward the second continuous layer, providing continuous pathways for conduction of holes to the first continuous layer. A second network of acceptor material or materials extends from the second continuous layer toward the first continuous layer, providing continuous pathways for conduction of electrons to the second continuous layer. The first network and the second network are interlaced with each other. At least one other photoconductive material is interspersed between the interlaced networks. This other photoconductive material or materials has an absorption spectra different from the donor and acceptor materials.

  12. DEVELOPMENT OF THE BULK TRITIUM SHIPPING PACKAGING

    SciTech Connect (OSTI)

    Blanton, P.; Eberl, K.

    2008-09-14

    A new radioactive shipping packaging for transporting bulk quantities of tritium, the Bulk Tritium Shipping Package (BTSP), has been designed for the Department of Energy (DOE) as a replacement for a package designed in the early 1970s. This paper summarizes significant design features and describes how the design satisfies the regulatory safety requirements of the Code of Federal Regulations and the International Atomic Energy Agency. The BTSP design incorporates many improvements over its predecessor by implementing improved testing, handling, and maintenance capabilities, while improving manufacturability and incorporating new engineered materials. This paper also discusses the results from testing of the BTSP to 10 CFR 71 Normal Conditions of Transport and Hypothetical Accident Condition events. The programmatic need of the Department of Energy (DOE) to ship bulk quantities of tritium has been satisfied since the late 1970s by the UC-609 shipping package. The current Certificate of Conformance for the UC-609, USA/9932/B(U) (DOE), will expire in late 2011. Since the UC-609 was not designed to meet current regulatory requirements, it will not be recertified and thereby necessitates a replacement Type B shipping package for continued DOE tritium shipments in the future. A replacement tritium packaging called the Bulk Tritium Shipping Package (BTSP) is currently being designed and tested by Savannah River National Laboratory (SRNL). The BTSP consists of two primary assemblies, an outer Drum Assembly and an inner Containment Vessel Assembly (CV), both designed to mitigate damage and to protect the tritium contents from leaking during the regulatory Hypothetical Accident Condition (HAC) events and during Normal Conditions of Transport (NCT). During transport, the CV rests on a silicone pad within the Drum Liner and is covered with a thermal insulating disk within the insulated Drum Assembly. The BTSP packaging weighs approximately 500 lbs without contents and is 50-1/2 inches high by 24-1/2 inches in outside diameter. With contents the gross weight of the BTSP is 650 lbs. The BTSP is designed for the safe shipment of 150 grams of tritium in a solid or gaseous state. To comply with the federal regulations that govern Type B shipping packages, the BTSP is designed so that it will not lose tritium at a rate greater than the limits stated in 10CFR 71.51 of 10{sup -6} A2 per hour for the 'Normal Conditions of Transport' (NCT) and an A2 in 1 week under 'Hypothetical Accident Conditions' (HAC). Additionally, since the BTSP design incorporates a valve as part of the tritium containment boundary, secondary containment features are incorporated in the CV Lid to protect against gas leakage past the valve as required by 10CFR71.43(e). This secondary containment boundary is designed to provide the same level of containment as the primary containment boundary when subjected to the HAC and NCT criteria.

  13. Consolidation of cubic and hexagonal boron nitride composites

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

    Du Frane, W. L.; Cervantes, O.; Ellsworth, G. F.; Kuntz, J. D.

    2015-12-08

    When we Consolidate cubic boron nitride (cBN) it typically requires either a matrix of metal bearing materials that are undesirable for certain applications, or very high pressures within the cBN phase stability field that are prohibitive to manufacturing size and cost. We present new methodology for consolidating high stiffness cBN composites within a hexagonal boron nitride (hBN) matrix (15–25 vol%) with the aid of a binder phase (0–6 vol%) at moderate pressures (0.5–1.0 GPa) and temperatures (900–1300 °C). The composites are demonstrated to be highly tailorable with a range of compositions and resulting physical/mechanical properties. Ultrasonic measurements indicate that inmore » some cases these composites have elastic mechanical properties that exceed those of the highest strength steel alloys. Moreover, two methods were identified to prevent phase transformation of the metastable cBN phase into hBN during consolidation: 1. removal of hydrocarbons, and 2. increased cBN particle size. Lithium tetraborate worked better as a binder than boron oxide, aiding consolidation without enhancing cBN to hBN phase transformation kinetics. These powder mixtures consolidated within error of their full theoretical mass densities at 1 GPa, and had only slightly lower densities at 0.5 GPa. This shows potential for consolidation of these composites into larger parts, in a variety of shapes, at even lower pressures using more conventional manufacturing methods, such as hot-pressing.« less

  14. Use of additives to improve microstructures and fracture resistance of silicon nitride ceramics

    DOE Patents [OSTI]

    Becher, Paul F. (Oak Ridge, TN); Lin, Hua-Tay (Oak Ridge, TN)

    2011-06-28

    A high-strength, fracture-resistant silicon nitride ceramic material that includes about 5 to about 75 wt-% of elongated reinforcing grains of beta-silicon nitride, about 20 to about 95 wt-% of fine grains of beta-silicon nitride, wherein the fine grains have a major axis of less than about 1 micron; and about 1 to about 15 wt-% of an amorphous intergranular phase comprising Si, N, O, a rare earth element and a secondary densification element. The elongated reinforcing grains have an aspect ratio of 2:1 or greater and a major axis measuring about 1 micron or greater. The elongated reinforcing grains are essentially isotropically oriented within the ceramic microstructure. The silicon nitride ceramic exhibits a room temperature flexure strength of 1,000 MPa or greater and a fracture toughness of 9 MPa-m.sup.(1/2) or greater. The silicon nitride ceramic exhibits a peak strength of 800 MPa or greater at 1200 degrees C. Also included are methods of making silicon nitride ceramic materials which exhibit the described high flexure strength and fracture-resistant values.

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

    SciTech Connect (OSTI)

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

    2013-01-01

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

  16. Thermodynamic properties of bulk and confined water

    SciTech Connect (OSTI)

    Mallamace, Francesco; Corsaro, Carmelo; Mallamace, Domenico; Vasi, Sebastiano; Vasi, Cirino; Stanley, H. Eugene

    2014-11-14

    The thermodynamic response functions of water display anomalous behaviors. We study these anomalous behaviors in bulk and confined water. We use nuclear magnetic resonance (NMR) to examine the configurational specific heat and the transport parameters in both the thermal stable and the metastable supercooled phases. The data we obtain suggest that there is a behavior common to both phases: that the dynamics of water exhibit two singular temperatures belonging to the supercooled and the stable phase, respectively. One is the dynamic fragile-to-strong crossover temperature (T{sub L} ? 225K). The second, T{sup *} ? 315 5K, is a special locus of the isothermal compressibility K{sub T}(T, P) and the thermal expansion coefficient ?{sub P}(T, P) in the PT plane. In the case of water confined inside a protein, we observe that these two temperatures mark, respectively, the onset of protein flexibility from its low temperature glass state (T{sub L}) and the onset of the unfolding process (T{sup *})

  17. Excitonic exchange splitting in bulk semiconductors

    SciTech Connect (OSTI)

    Fu, H.; Wang, L.; Zunger, A.

    1999-02-01

    We present an approach to calculate the excitonic fine-structure splittings due to electron-hole short-range exchange interactions using the local-density approximation pseudopotential method, and apply it to bulk semiconductors CdSe, InP, GaAs, and InAs. Comparing with previous theoretical results, the current calculated splittings agree well with experiments. Furthermore, we provide an approximate relationship between the short-range exchange splitting and the exciton Bohr radius, which can be used to estimate the exchange splitting for other materials. The current calculation indicates that a commonly used formula for exchange splitting in quantum dot is not valid. Finally, we find a very large pressure dependence of the exchange splitting: a factor of 4.5 increase as the lattice constant changes by 3.5{percent}. This increase is mainly due to the decrease of the Bohr radius via the change of electron effective mass. {copyright} {ital 1999} {ital The American Physical Society}

  18. Determination of Bulk Dimensional Variation in Castings

    SciTech Connect (OSTI)

    Dr. James F. Cuttino Dr. Edward P. Morse

    2005-04-14

    The purpose of this work is to improve the efficiency of green sand foundries so that they may continue to compete as the most cost-effective method of fabrication while meeting tightening constraints on near-net shape manufacturing. In order to achieve this objective, the study is divided into two major components. The first component concentrated on identifying which processes control surface finish on the castings and which provide potential reductions in variations. The second component identified metrological methods that effectively discern between the geometry of bulk material versus surface finish in order to more accurately determine the quality of a part. The research resulted in the determination of an empirical relationship relating pouring parameters to dimensional variation, with an R2 value of greater than 0.79. A significant difference in variations obtained from vertical vs. horizontal molding machines was also noticed. When analyzed separately, however, the resulting empirical relationships for horizontal and vertical machines had reduced R2 values, probably due to the reduced data sets. Significant parameters when considering vertical and horizontal molding machines together included surface roughness, pattern type, iron type, pouring rate, copper content, amount of Western Bentonite, and permeability.

  19. High Heat Flux Thermoelectric Module Using Standard Bulk Material |

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

    Department of Energy Heat Flux Thermoelectric Module Using Standard Bulk Material High Heat Flux Thermoelectric Module Using Standard Bulk Material Presents high heat flux thermoelectric module design for cooling using a novel V-shaped shunt configuration with bulk TE elements achieving high area packing fractions PDF icon crane.pdf More Documents & Publications Potential of Thermoelectrics forOccupant Comfort and Fuel Efficiency Gains in Vehicle Applications Development of a 100-Watt

  20. Design of Bulk Nanocomposites as High Efficiency Thermoelectric Materials |

    Office of Science (SC) Website

    U.S. DOE Office of Science (SC) Design of Bulk Nanocomposites as High Efficiency Thermoelectric Materials Energy Frontier Research Centers (EFRCs) EFRCs Home Centers Research Science Highlights Highlight Archives News & Events Publications History Contact BES Home 04.27.12 Design of Bulk Nanocomposites as High Efficiency Thermoelectric Materials Print Text Size: A A A FeedbackShare Page Scientific Achievement A newly synthesized bulk thermoelectric material that contains nanocrystals

  1. Recent Device Developments with Advanced Bulk Thermoelectric Materials at

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

    RTI | Department of Energy Device Developments with Advanced Bulk Thermoelectric Materials at RTI Recent Device Developments with Advanced Bulk Thermoelectric Materials at RTI Reviews work in engineered thin-film nanoscale thermoelectric materials and nano-bulk materials with high ZT undertaken by RTI in collaboration with its research partners PDF icon venkatasubramanian.pdf More Documents & Publications Nano-structures Thermoelectric Materals - Part 1 Nano-structures Thermoelectric

  2. ARM - Campaign Instrument - ec-convair580-bulk

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

    govInstrumentsec-convair580-bulk Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign Instrument : Environment Canada Convair 580 Bulk Parameters (EC-CONVAIR580-BULK) Instrument Categories Aerosols, Airborne Observations, Cloud Properties Campaigns Indirect and Semi-Direct Aerosol Campaign (ISDAC) [ Download Data ] North Slope Alaska, 2008.04.01 - 2008.04.30 Primary Measurements Taken The following measurements are those considered

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

    DOE Patents [OSTI]

    Han, Jung; Figiel, Jeffrey J.

    2002-01-01

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

  4. Influence of hydrogen effusion from hydrogenated silicon nitride layers on the regeneration of boron-oxygen related defects in crystalline silicon

    SciTech Connect (OSTI)

    Wilking, S. Ebert, S.; Herguth, A.; Hahn, G.

    2013-11-21

    The degradation effect boron doped and oxygen-rich crystalline silicon materials suffer from under illumination can be neutralized in hydrogenated silicon by the application of a regeneration process consisting of a combination of slightly elevated temperature and carrier injection. In this paper, the influence of variations in short high temperature steps on the kinetics of the regeneration process is investigated. It is found that hotter and longer firing steps allowing an effective hydrogenation from a hydrogen-rich silicon nitride passivation layer result in an acceleration of the regeneration process. Additionally, a fast cool down from high temperature to around 550?C seems to be crucial for a fast regeneration process. It is suggested that high cooling rates suppress hydrogen effusion from the silicon bulk in a temperature range where the hydrogenated passivation layer cannot release hydrogen in considerable amounts. Thus, the hydrogen content of the silicon bulk after the complete high temperature step can be increased resulting in a faster regeneration process. Hence, the data presented here back up the theory that the regeneration process might be a hydrogen passivation of boron-oxygen related defects.

  5. Investigation of Interfacial and Bulk Dissociation of HBr, HCl...

    Office of Scientific and Technical Information (OSTI)

    Investigation of Interfacial and Bulk Dissociation of HBr, HCl, and HNO3 Using Density Functional Theory-Based Molecular Dynamics Simulations Citation Details In-Document Search...

  6. RAPID/BulkTransmission/Land Access | Open Energy Information

    Open Energy Info (EERE)

    RAPIDBulkTransmissionLand Access < RAPID | BulkTransmission(Redirected from RAPIDBulkTransmissionLeasing) Jump to: navigation, search RAPID Regulatory and Permitting...

  7. Economic manufacturing of bulk metallic glass compositions by microalloying

    DOE Patents [OSTI]

    Liu, Chain T.

    2003-05-13

    A method of making a bulk metallic glass composition includes the steps of:a. providing a starting material suitable for making a bulk metallic glass composition, for example, BAM-11; b. adding at least one impurity-mitigating dopant, for example, Pb, Si, B, Sn, P, to the starting material to form a doped starting material; and c. converting the doped starting material to a bulk metallic glass composition so that the impurity-mitigating dopant reacts with impurities in the starting material to neutralize deleterious effects of the impurities on the formation of the bulk metallic glass composition.

  8. RAPID/BulkTransmission/Site Considerations | Open Energy Information

    Open Energy Info (EERE)

    and comparison for Bulk Transmission Site Considerations across various states. To learn more detailed information about Site Considerations in a state, click on the...

  9. Strategies for High Thermoelectric zT in Bulk Materials

    Broader source: Energy.gov [DOE]

    Zintl principle in chemistry, complex electronic band structures, and incorporation of nanometer sized particles were used to explore, optimize and improve bulk thermoelectric materials

  10. Category:Bulk Transmission Regulatory Roadmap Sections | Open...

    Open Energy Info (EERE)

    Login | Sign Up Search Category Edit History Category:Bulk Transmission Regulatory Roadmap Sections Jump to: navigation, search GRR-logo.png Looking for the RAPIDRoadmap?...

  11. RAPID/BulkTransmission/Federal | Open Energy Information

    Open Energy Info (EERE)

    Permitting Information Desktop Toolkit BETA About Bulk Transmission Geothermal Hydropower Solar Tools Contribute Contact Us Regulatory Information Overviews Search for other...

  12. RAPID/BulkTransmission/Environment | Open Energy Information

    Open Energy Info (EERE)

    Policy Act (HEPA) Hawaii Department of Health Office of Environmental Quality Control Bulk Transmission Environment in Idaho Varies by local municipality Varies by...

  13. RAPID/BulkTransmission/Colorado | Open Energy Information

    Open Energy Info (EERE)

    the Regional Entity responsible for coordinating and promoting Bulk Electric System reliability in the Western Interconnection, including in Colorado. In addition, WECC provides...

  14. RAPID/BulkTransmission/Idaho | Open Energy Information

    Open Energy Info (EERE)

    the Regional Entity responsible for coordinating and promoting Bulk Electric System reliability in the Western Interconnection, including in Idaho. In addition, WECC provides an...

  15. RAPID/BulkTransmission/Washington | Open Energy Information

    Open Energy Info (EERE)

    the Regional Entity responsible for coordinating and promoting Bulk Electric System reliability in the Western Interconnection, including in Washington. In addition, WECC provides...

  16. RAPID/BulkTransmission/Nevada | Open Energy Information

    Open Energy Info (EERE)

    the Regional Entity responsible for coordinating and promoting Bulk Electric System reliability in the Western Interconnection, including in Nevada. WECC also provides an...

  17. RAPID/BulkTransmission/Arizona | Open Energy Information

    Open Energy Info (EERE)

    the Regional Entity responsible for coordinating and promoting Bulk Electric System reliability in the Western Interconnection, including Arizona. WECC also provides an...

  18. RAPID/BulkTransmission/Oregon | Open Energy Information

    Open Energy Info (EERE)

    the Regional Entity responsible for coordinating and promoting Bulk Electric System reliability in the Western Interconnection, including Oregon. WECC also provides an environment...

  19. The Best of Both Worlds: Bulk Diamond Properties Realized at...

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

    a level of crystallographic and electronic ordering in purified HPHT nanodiamonds that matches fundamental properties of bulk diamond to the nanoscale while retaining its...

  20. Federal Bulk Transmission Regulatory Roadmapping | OpenEI Community

    Open Energy Info (EERE)

    Federal Bulk Transmission Regulatory Roadmapping Home > Features > Groups Content Group Activity By term Q & A Feeds Content type Blog entry Discussion Document Event Poll...

  1. RAPID/BulkTransmission/Hawaii | Open Energy Information

    Open Energy Info (EERE)

    information about BulkTransmission in Hawaii. Use the Edit with form button to editupdate. Planning Organizations not provided Hawaii Owners not provided Current Projects not...

  2. RAPID/BulkTransmission/Alaska | Open Energy Information

    Open Energy Info (EERE)

    information about BulkTransmission in Alaska. Use the Edit with form button to editupdate. Planning Organizations not provided Alaska Owners not provided Current Projects not...

  3. RAPID/BulkTransmission/Texas | Open Energy Information

    Open Energy Info (EERE)

    information about BulkTransmission in Texas. Use the Edit with form button to editupdate. Planning Organizations not provided Texas Owners not provided Current Projects not...

  4. Lithium Ion Solvation and Diffusion in Bulk Organic Electrolytes...

    Office of Scientific and Technical Information (OSTI)

    Lithium Ion Solvation and Diffusion in Bulk Organic Electrolytes from First Principles and Classical Reactive Molecular Dynamics Citation Details In-Document Search Title: Lithium...

  5. Lithium Ion Solvation and Diffusion in Bulk Organic Electrolytes...

    Office of Scientific and Technical Information (OSTI)

    Conference: Lithium Ion Solvation and Diffusion in Bulk Organic Electrolytes from First Principles Molecular Dynamics Citation Details In-Document Search Title: Lithium Ion...

  6. Boundary Entropy Can Increase Under Bulk RG Flow (Journal Article...

    Office of Scientific and Technical Information (OSTI)

    The boundary entropy log(g) can therefore increase during appropriate bulk flows. This is demonstrated explicitly in flows between minimal models. We discuss the applications of ...

  7. RAPID/BulkTransmission/About | Open Energy Information

    Open Energy Info (EERE)

    Current Topics in Bulk Transmission West-Wide Energy Corridor Programmatic Environmental Impact Statement The West-Wide Energy Corridor Programmatic Environmental Impact Statement...

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

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

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

    2015-01-01

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

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

    SciTech Connect (OSTI)

    Wampler, William R.; Myers, Samuel M.

    2014-02-01

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

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

    SciTech Connect (OSTI)

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

    2015-01-01

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

  11. Bulk Vitrification Castable Refractory Block Protection Study

    SciTech Connect (OSTI)

    Hrma, Pavel R.; Bagaasen, Larry M.; Beck, Andrew E.; Brouns, Thomas M.; Caldwell, Dustin D.; Elliott, Michael L.; Matyas, Josef; Minister, Kevin BC; Schweiger, Michael J.; Strachan, Denis M.; Tinsley, Bronnie P.; Hollenberg, Glenn W.

    2005-05-01

    Bulk vitrification (BV) was selected for a pilot-scale test and demonstration facility for supplemental treatment to accelerate the cleanup of low-activity waste (LAW) at the Hanford U.S. DOE Site. During engineering-scale (ES) tests, a small fraction of radioactive Tc (and Re, its nonradioactive surrogate) were transferred out of the LAW glass feed and molten LAW glass, and deposited on the surface and within the pores of the castable refractory block (CRB). Laboratory experiments were undertaken to understand the mechanisms of the transport Tc/Re into the CRB during vitrification and to evaluate various means of CRB protection against the deposition of leachable Tc/Re. The tests used Re as a chemical surrogate for Tc. The tests with the baseline CRB showed that the molten LAW penetrates into CRB pores before it converts to glass, leaving deposits of sulfates and chlorides when the nitrate components decompose. Na2O from the LAW reacts with the CRB to create a durable glass phase that may contain Tc/Re. Limited data from a single CRB sample taken from an ES experiment indicate that, while a fraction of Tc/Re is present in the CRB in a readily leachable form, most of the Tc/Re deposited in the refractory is retained in the form of a durable glass phase. In addition, the molten salts from the LAW, mainly sulfates, chlorides, and nitrates, begin to evaporate from BV feeds at temperatures below 800 C and condense on solid surfaces at temperatures below 530 C. Three approaches aimed at reducing or preventing the deposition of soluble Tc/Re within the CRB were proposed: metal lining, sealing the CRB surface with a glaze, and lining the CRB with ceramic tiles. Metal liners were deemed unsuitable because evaluations showed that they can cause unacceptable distortions of the electric field in the BV system. Sodium silicate and a low-alkali borosilicate glaze were selected for testing. The glazes slowed down molten salt condensate penetration, but did little to reduce the penetration of molten salt. Out of several refractory tile candidates, only greystone and fused-cast alumina-zirconia-silica (AZS) refractory remained intact and well bonded to the CRB after firing to 1000 C. The deformation of the refractory-tile composite was avoided by prefiring the greystone tile to 800 C. Condensed vapors did not penetrate the tiles, but Re salts condensed on their surface. Refractory corrosion tests indicated that a 0.25-inch-thick greystone tile would not corrode during a BV melt. Tiles can reduce both vapor penetration and molten salt penetration, but vapor deposition above the melt line will occur even on tiles. The Tc/Re transport scenario was outlined as follows. At temperatures below 700 C, molten ionic salt (MIS) that includes all the Tc/Re penetrates, by capillarity, from the feed into the CRB open porosity. At approximately 750 C, the MIS decomposes through the loss of NOx, leaving mainly sulfate and chloride salts. The Na2O formed in the decomposition of the nitrates reacts with insoluble grains in the feed and with the aluminosilicates in the CRB to form more viscous liquids that reduce further liquid penetration into the CRB. At 800 to 1000 C, a continuous glass phase traps the remains of the MIS in the form of inclusions in the bulk glass melt. At 1000 to 1200 C, the salt inclusions in the glass slowly dissolve but also rise to the surface. The Tc/Re salts also evaporate from the free surface of the glass melt that is rapidly renewed by convective currents. The vapors condense on cooler surfaces in the upper portion of the CRB, the box lid, and the off-gas system.

  12. Silicon bulk micromachined hybrid dimensional artifact.

    SciTech Connect (OSTI)

    Claudet, Andre A.; Tran, Hy D.; Bauer, Todd Marks; Shilling, Katherine Meghan; Oliver, Andrew David

    2010-03-01

    A mesoscale dimensional artifact based on silicon bulk micromachining fabrication has been developed and manufactured with the intention of evaluating the artifact both on a high precision coordinate measuring machine (CMM) and video-probe based measuring systems. This hybrid artifact has features that can be located by both a touch probe and a video probe system with a k=2 uncertainty of 0.4 {micro}m, more than twice as good as a glass reference artifact. We also present evidence that this uncertainty could be lowered to as little as 50 nm (k=2). While video-probe based systems are commonly used to inspect mesoscale mechanical components, a video-probe system's certified accuracy is generally much worse than its repeatability. To solve this problem, an artifact has been developed which can be calibrated using a commercially available high-accuracy tactile system and then be used to calibrate typical production vision-based measurement systems. This allows for error mapping to a higher degree of accuracy than is possible with a glass reference artifact. Details of the designed features and manufacturing process of the hybrid dimensional artifact are given and a comparison of the designed features to the measured features of the manufactured artifact is presented and discussed. Measurement results from vision and touch probe systems are compared and evaluated to determine the capability of the manufactured artifact to serve as a calibration tool for video-probe systems. An uncertainty analysis for calibration of the artifact using a CMM is presented.

  13. Process for producing silicon nitride based articles of high fracture toughness and strength

    DOE Patents [OSTI]

    Huckabee, M.; Buljan, S.T.; Neil, J.T.

    1991-09-10

    A process for producing a silicon nitride-based article of improved fracture toughness and strength is disclosed. The process involves densifying to at least 98% of theoretical density a mixture including (a) a bimodal silicon nitride powder blend consisting essentially of about 10-30% by weight of a first silicon nitride powder of an average particle size of about 0.2 [mu]m and a surface area of about 8-12 m[sup 2]/g, and about 70-90% by weight of a second silicon nitride powder of an average particle size of about 0.4-0.6 [mu]m and a surface area of about 2-4 m[sup 2]/g, (b) about 10-50 percent by volume, based on the volume of the densified article, of refractory whiskers or fibers having an aspect ratio of about 3-150 and having an equivalent diameter selected to produce in the densified article an equivalent diameter ratio of the whiskers or fibers to grains of silicon nitride of greater than 1.0, and (c) an effective amount of a suitable oxide densification aid. Optionally, the mixture may be blended with a binder and injection molded to form a green body, which then may be densified by, for example, hot isostatic pressing.

  14. Process for producing silicon nitride based articles of high fracture toughness and strength

    DOE Patents [OSTI]

    Huckabee, Marvin (Marlboro, MA); Buljan, Sergej-Tomislav (Acton, MA); Neil, Jeffrey T. (Acton, MA)

    1991-01-01

    A process for producing a silicon nitride-based article of improved fracture toughness and strength. The process involves densifying to at least 98% of theoretical density a mixture including (a) a bimodal silicon nitride powder blend consisting essentially of about 10-30% by weight of a first silicon nitride powder of an average particle size of about 0.2 .mu.m and a surface area of about 8-12 m.sup.2 /g, and about 70-90% by weight of a second silicon nitride powder of an average particle size of about 0.4-0.6 .mu.m and a surface area of about 2-4 m.sup.2 /g, (b) about 10-50 percent by volume, based on the volume of the densified article, of refractory whiskers or fibers having an aspect ratio of about 3-150 and having an equivalent diameter selected to produce in the densified article an equivalent diameter ratio of the whiskers or fibers to grains of silicon nitride of greater than 1.0, and (c) an effective amount of a suitable oxide densification aid. Optionally, the mixture may be blended with a binder and injection molded to form a green body, which then may be densified by, for example, hot isostatic pressing.

  15. Thermal transport across graphene and single layer hexagonal boron nitride

    SciTech Connect (OSTI)

    Zhang, Jingchao E-mail: yyue@whu.edu.cn; Hong, Yang; Yue, Yanan E-mail: yyue@whu.edu.cn

    2015-04-07

    As the dimensions of nanocircuits and nanoelectronics shrink, thermal energies are being generated in more confined spaces, making it extremely important and urgent to explore for efficient heat dissipation pathways. In this work, the phonon energy transport across graphene and hexagonal boron-nitride (h-BN) interface is studied using classic molecular dynamics simulations. Effects of temperature, interatomic bond strength, heat flux direction, and functionalization on interfacial thermal transport are investigated. It is found out that by hydrogenating graphene in the hybrid structure, the interfacial thermal resistance (R) between graphene and h-BN can be reduced by 76.3%, indicating an effective approach to manipulate the interfacial thermal transport. Improved in-plane/out-of-plane phonon couplings and broadened phonon channels are observed in the hydrogenated graphene system by analyzing its phonon power spectra. The reported R results monotonically decrease with temperature and interatomic bond strengths. No thermal rectification phenomenon is observed in this interfacial thermal transport. Results reported in this work give the fundamental knowledge on graphene and h-BN thermal transport and provide rational guidelines for next generation thermal interface material designs.

  16. Mechanical deformations of boron nitride nanotubes in crossed junctions

    SciTech Connect (OSTI)

    Zhao, Yadong; Chen, Xiaoming; Ke, Changhong; Park, Cheol; Fay, Catharine C.; Stupkiewicz, Stanislaw

    2014-04-28

    We present a study of the mechanical deformations of boron nitride nanotubes (BNNTs) in crossed junctions. The structure and deformation of the crossed tubes in the junction are characterized by using atomic force microscopy. Our results show that the total tube heights are reduced by 20%33% at the crossed junctions formed by double-walled BNNTs with outer diameters in the range of 2.214.67?nm. The measured tube height reduction is found to be in a nearly linear relationship with the summation of the outer diameters of the two tubes forming the junction. The contact force between the two tubes in the junction is estimated based on contact mechanics theories and found to be within the range of 4.27.6 nN. The Young's modulus of BNNTs and their binding strengths with the substrate are quantified, based on the deformation profile of the upper tube in the junction, and are found to be 1.07??0.11 TPa and 0.180.29 nJ/m, respectively. Finally, we perform finite element simulations on the mechanical deformations of the crossed BNNT junctions. The numerical simulation results are consistent with both the experimental measurements and the analytical analysis. The results reported in this paper contribute to a better understanding of the structural and mechanical properties of BNNTs and to the pursuit of their applications.

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

    SciTech Connect (OSTI)

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

    2014-10-23

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

  18. Bulk Hauling Equipment for CHG | Department of Energy

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

    Bulk Hauling Equipment for CHG Bulk Hauling Equipment for CHG This presentation by Don Baldwin of Hexagon Composites was given at the DOE Hydrogen Compression, Storage, and Dispensing Workshop in March 2013. PDF icon csd_workshop_8_baldwin.pdf More Documents & Publications Tank Manufacturing, Testing, Deployment and Field Performance Hydrogen Delivery Roadmap US DRIVE Hydrogen Delivery Technical Team Roadmap

  19. Carbon nanotubes grown on bulk materials and methods for fabrication

    DOE Patents [OSTI]

    Menchhofer, Paul A. (Clinton, TN); Montgomery, Frederick C. (Oak Ridge, TN); Baker, Frederick S. (Oak Ridge, TN)

    2011-11-08

    Disclosed are structures formed as bulk support media having carbon nanotubes formed therewith. The bulk support media may comprise fibers or particles and the fibers or particles may be formed from such materials as quartz, carbon, or activated carbon. Metal catalyst species are formed adjacent the surfaces of the bulk support material, and carbon nanotubes are grown adjacent the surfaces of the metal catalyst species. Methods employ metal salt solutions that may comprise iron salts such as iron chloride, aluminum salts such as aluminum chloride, or nickel salts such as nickel chloride. Carbon nanotubes may be separated from the carbon-based bulk support media and the metal catalyst species by using concentrated acids to oxidize the carbon-based bulk support media and the metal catalyst species.

  20. Synthesis of fine-grained .alpha.-silicon nitride by a combustion process

    DOE Patents [OSTI]

    Holt, J. Birch (San Jose, CA); Kingman, Donald D. (Danville, CA); Bianchini, Gregory M. (Livermore, CA)

    1990-01-01

    A combustion synthesis process for the preparation of .alpha.-silicon nitride and composites thereof is disclosed. Preparation of the .alpha.-silicon nitride comprises the steps of dry mixing silicon powder with an alkali metal azide, such as sodium azide, cold-pressing the mixture into any desired shape, or loading the mixture into a fused, quartz crucible, loading the crucible into a combustion chamber, pressurizing the chamber with nitrogen and igniting the mixture using an igniter pellet. The method for the preparation of the composites comprises dry mixing silicon powder (Si) or SiO.sub.2, with a metal or metal oxide, adding a small amount of an alkali metal azide such as sodium azide, introducing the mixture into a suitable combustion chamber, pressurizing the combustion chamber with nitrogen, igniting the mixture within the combustion chamber, and isolating the .alpha.-silicon nitride formed as a reaction product.

  1. The different adsorption mechanism of methane molecule onto a boron nitride and a graphene flakes

    SciTech Connect (OSTI)

    Seyed-Talebi, Seyedeh Mozhgan; Neek-Amal, M.

    2014-10-21

    Graphene and single layer hexagonal boron-nitride are two newly discovered 2D materials with wonderful physical properties. Using density functional theory, we study the adsorption mechanism of a methane molecule over a hexagonal flake of single layer hexagonal boron-nitride (h-BN) and compare the results with those of graphene. We found that independent of the used functional in our ab-initio calculations, the adsorption energy in the h-BN flake is larger than that for graphene. Despite of the adsorption energy profile of methane over a graphene flake, we show that there is a long range behavior beyond minimum energy in the adsorption energy of methane over h-BN flake. This result reveals the higher sensitivity of h-BN sheet to the adsorption of a typical closed shell molecule with respect to graphene. The latter gives insight in the recent experiments of graphene over hexagonal boron nitride.

  2. Structural modifications due to interface chemistry at metal-nitride interfaces

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

    Yadav, S. K.; Shao, S.; Wang, J.; Liu, X. -Y.

    2015-11-27

    Based on accurate first principles density functional theory (DFT) calculations, an unusual phenomenon of interfacial structural modifications, due to the interface chemistry influence is identified at two metal-nitride interfaces with strong metal-nitrogen affinity, Al/TiN {111} and Al/VN {111} interfaces. It is shown that at such interfaces, a faulted stacking structure is energetically preferred on the Al side of the interface. And both intrinsic and extrinsic stacking fault energies in the vicinity Al layers are negligibly small. However, such phenomenon does not occur in Pt/TiN and Pt/VN interfaces because of the weak Pt-N affinity. As a result, corresponding to structural energiesmore » of metal-nitride interfaces, the linear elasticity analysis predicts characteristics of interfacial misfit dislocations at metal-nitride interfaces.« less

  3. Influence of slurry flocculation on the character and compaction of spray-dried silicon nitride granules

    SciTech Connect (OSTI)

    Takahashi, Hideo; Shinohara, Nobuhiro; Okumiya, Masataro; Uematsu, Keizo; JunIchiro, Tsubaki; Iwamoto, Yuji; Kamiya, Hidehiro

    1995-04-01

    The effect of slurry flocculation on the characteristics of silicon nitride granules prepared by the spray drying process is investigated. The flocculation state of an aqueous silicon nitride slurry is controlled by adding nitric acid and evaluated as a function of pH. Dense and hard silicon nitride granules result from a well-dispersed slurry having a high pH (e.g., 10.8). These hard granules retain their shape in green compacts and form detrimental defects. Lowering the pH of the slurry to a certain value (e.g., pH 7.9) results in slurry flocculation. Granules prepared from this flocculated slurry have low density and low diametral compression strength and contribute to the elimination large pores in green compacts.

  4. Nitrided iron catalysts for the Fischer-Tropsch synthesis in the eighties

    SciTech Connect (OSTI)

    Anderson, R.B.

    1980-01-01

    A survey covers the preparation and structure of nitrided iron catalysts and their activity, selectivity, and stability for the reaction of synthesis gas in comparison with iron catalysts pretreated by various other methods, as measured in laboratory reactors; a comparison of product distributions obtained in fluidized-bed, slurry, and oil-circulation fixed bed pilot plants with nitrided catalysts and by the Kellogg entrained catalyst process SASOL, which uses a reduced iron catalyst; and possible methods for refining the Fischer-Tropsch products from nitrided iron catalysts for producing gasoline, including bauxite treatment, the Mobil process for converting oxygenates to high-octane gasoline and C/sub 3/-C/sub 4/ olefins, and an alkylation-polymerization process for converting the C/sub 3/-C/sub 4/ fraction to high-octane blending stocks.

  5. Effect of hydrogen passivation on charge storage in silicon quantum dots embedded in silicon nitride film

    SciTech Connect (OSTI)

    Cho, Chang-Hee; Kim, Baek-Hyun; Kim, Tae-Wook; Park, Seong-Ju; Park, Nae-Man; Sung, Gun-Yong

    2005-04-04

    The effect of hydrogen passivation on the charge storage characteristics of two types of silicon nitride films containing silicon quantum dots (Si QDs) grown by SiH{sub 4}+N{sub 2} and SiH{sub 4}+NH{sub 3} plasma was investigated. The transmission electron microscope analysis and the capacitance-voltage measurement showed that the silicon nitride film grown by SiH{sub 4}+NH{sub 3} plasma has a lower interface trap density and a higher density of Si QDs compared to that grown by SiH{sub 4}+N{sub 2} plasma. It was also found that the charge retention characteristics in the Si QDs were greatly enhanced in the samples grown by means of SiH{sub 4}+NH{sub 3} plasma, due to the hydrogen passivation of the defects in the silicon nitride films by NH{sub 3} during the growth of the Si QDs.

  6. Si Passivation and Chemical Vapor Deposition of Silicon Nitride: Final Technical Report, March 18, 2007

    SciTech Connect (OSTI)

    Atwater, H. A.

    2007-11-01

    This report investigated chemical and physical methods for Si surface passivation for application in crystalline Si and thin Si film photovoltaic devices. Overall, our efforts during the project were focused in three areas: i) synthesis of silicon nitride thin films with high hydrogen content by hot-wire chemical vapor deposition; ii) investigation of the role of hydrogen passivation of defects in crystalline Si and Si solar cells by out diffusion from hydrogenated silicon nitride films; iii) investigation of the growth kinetics and passivation of hydrogenated polycrystalline. Silicon nitride films were grown by hot-wire chemical vapor deposition and film properties have been characterized as a function of SiH4/NH3 flow ratio. It was demonstrated that hot-wire chemical vapor deposition leads to growth of SiNx films with controllable stoichiometry and hydrogen.

  7. Structural modifications due to interface chemistry at metal-nitride interfaces

    SciTech Connect (OSTI)

    Yadav, S. K.; Shao, S.; Wang, J.; Liu, X. -Y.

    2015-11-27

    Based on accurate first principles density functional theory (DFT) calculations, an unusual phenomenon of interfacial structural modifications, due to the interface chemistry influence is identified at two metal-nitride interfaces with strong metal-nitrogen affinity, Al/TiN {111} and Al/VN {111} interfaces. It is shown that at such interfaces, a faulted stacking structure is energetically preferred on the Al side of the interface. And both intrinsic and extrinsic stacking fault energies in the vicinity Al layers are negligibly small. However, such phenomenon does not occur in Pt/TiN and Pt/VN interfaces because of the weak Pt-N affinity. As a result, corresponding to structural energies of metal-nitride interfaces, the linear elasticity analysis predicts characteristics of interfacial misfit dislocations at metal-nitride interfaces.

  8. Thermal conductivity of nitride films of Ti, Cr, and W deposited by reactive magnetron sputtering

    SciTech Connect (OSTI)

    Jagannadham, Kasichainula

    2015-05-15

    Nitride films of Ti, Cr, and W were deposited using reactive magnetron sputtering from metal targets in argon and nitrogen plasma. TiN films with (200) orientation were achieved on silicon (100) at the substrate temperature of 500 and 600?C. The films were polycrystalline at lower temperature. An amorphous interface layer was observed between the TiN film and Si wafer deposited at 600?C. TiN film deposited at 600?C showed the nitrogen to Ti ratio to be near unity, but films deposited at lower temperature were nitrogen deficient. CrN film with (200) orientation and good stoichiometry was achieved at 600?C on Si(111) wafer but the film deposited at 500?C showed cubic CrN and hexagonal Cr{sub 2}N phases with smaller grain size and amorphous back ground in the x-ray diffraction pattern. An amorphous interface layer was not observed in the cubic CrN film on Si(111) deposited at 600?C. Nitride film of tungsten deposited at 600?C on Si(100) wafer was nitrogen deficient, contained both cubic W{sub 2}N and hexagonal WN phases with smaller grain size. Nitride films of tungsten deposited at 500?C were nonstoichiometric and contained cubic W{sub 2}N and unreacted W phases. There was no amorphous phase formed along the interface for the tungsten nitride film deposited at 600?C on the Si wafer. Thermal conductivity and interface thermal conductance of all the nitride films of Ti, Cr, and W were determined by transient thermoreflectance technique. The thermal conductivity of the films as function of deposition temperature, microstructure, nitrogen stoichiometry and amorphous interaction layer at the interface was determined. Tungsten nitride film containing both cubic and hexagonal phases was found to exhibit much higher thermal conductivity and interface thermal conductance. The amorphous interface layer was found to reduce effective thermal conductivity of TiN and CrN films.

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

    SciTech Connect (OSTI)

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

    1982-06-01

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

  10. Efficient boron nitride nanotube formation via combined laser-gas flow levitation

    DOE Patents [OSTI]

    Whitney, R. Roy; Jordan, Kevin; Smith, Michael

    2014-03-18

    A process for producing boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula B.sub.xC.sub.yN.sub.z. The process utilizes a combination of laser light and nitrogen gas flow to support a boron ball target during heating of the boron ball target and production of a boron vapor plume which reacts with nitrogen or nitrogen and carbon to produce boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula B.sub.xC.sub.yN.sub.z.

  11. Hands-On Session 6: Monolayer Boron Nitride BerkeleyGW Workshop

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

    Hands-On Session 6: Monolayer Boron Nitride BerkeleyGW Workshop 11/23/2013 Diana Qiu Goals: 1. Demonstrate a GW-BSE calculation for a 2D semiconductor 2. Look at the behavior of ε -1 00 (q) for a system with a truncated Coulomb interaction 3. Learn how to use BerkeleyGW's visualization tools to look at the exciton wave function Instructions: Please copy the example directory into your scratch directory >> cp -rP /project/projectdirs/m1694/BGW-2013/6-boron_nitride $SCRATCH/ 1-MF ● Please

  12. Alternative Liquid Fuel Effects on Cooled Silicon Nitride Marine Gas Turbine Airfoils

    SciTech Connect (OSTI)

    Holowczak, J.

    2002-03-01

    With prior support from the Office of Naval Research, DARPA, and U.S. Department of Energy, United Technologies is developing and engine environment testing what we believe to be the first internally cooled silicon nitride ceramic turbine vane in the United States. The vanes are being developed for the FT8, an aeroderivative stationary/marine gas turbine. The current effort resulted in further manufacturing and development and prototyping by two U.S. based gas turbine grade silicon nitride component manufacturers, preliminary development of both alumina, and YTRIA based environmental barrier coatings (EBC's) and testing or ceramic vanes with an EBC coating.

  13. Half metallic ferromagnetism in alkali metal nitrides MN (M = Rb, Cs): A first principles study

    SciTech Connect (OSTI)

    Murugan, A. Rajeswarapalanichamy, R. Santhosh, M. Sudhapriyanga, G.; Kanagaprabha, S.

    2014-04-24

    The structural, electronic and elastic properties of two alkali metal nitrides (MN: M= Rb, Cs) are investigated by the first principles calculations based on density functional theory using the Vienna ab-initio simulation package. At ambient pressure the two nitrides are stable in ferromagnetic state with CsCl structure. The calculated lattice parameters are in good agreement with the available results. The electronic structure reveals that these materials are half metallic in nature. A pressure-induced structural phase transition from CsCl to ZB phase is observed in RbN and CsN.

  14. Improved porous mixture of molybdenum nitride and tantalum oxide as a charge storage material

    SciTech Connect (OSTI)

    Deng, C.Z.; Pynenburg, R.A.J.; Tsai, K.C.

    1998-04-01

    High surface area {gamma}-molybdenum nitride has shown promise as a charge storage material. The addition of amorphous tantalum oxide to the molybdenum nitride system not only improves the film cohesion tremendously, but also widens the voltage stability window from 0.8 to 1.1 V. This occurs without adversely effecting the capacitance. Ultracapacitors, also called supercapacitors or electrochemical capacitors, are high power storage devices which have found application in products as diverse as cardiac pacemakers, cellular phones, electric vehicles, and air bags.

  15. Cycling Endurance of SONOS Non-Volatile Memory Stacks Prepared with Nitrided SiO(2)/Si(100) Intefaces

    SciTech Connect (OSTI)

    Habermehl, S.; Nasby, R.D.; Rightley, M.J.

    1999-01-11

    The effects of nitrided SiO{sub 2}/Si(100) interfaces upon cycling endurance in silicon-oxide-nitride-oxide-silicon (SONOS) non-volatile memory transistors are investigated. Analysis of MOSFET sub-threshold characteristics indicate cycling degradation to be a manifestation of interface state (D{sub it}) generation at the tunnel oxide/silicon interface. After 10{sup 6} write/erase cycles, SONOS film stacks prepared with nitrided tunnel oxides exhibit enhanced cycling endurance with {Delta}D{sub it}=3x10{sup 12} V{sup -1}cm{sup -2}, compared to {Delta}D{sub it}=2x10{sup 13} V{sup -l}cm{sup -2} for non-nitrided tunnel oxides. Additionally, if the capping oxide is formed by steam oxidation, rather than by deposition, SONOS stacks prepared with non-nitrided tunnel oxides exhibit endurance characteristics similar to stacks with nitrided tunnel oxides. From this observation it is concluded that latent nitridation of the tunnel oxidehilicon interface occurs during steam oxide cap formation.

  16. Bulk viscosity of anisotropically expanding hot QCD plasma

    SciTech Connect (OSTI)

    Chandra, Vinod

    2011-11-01

    The bulk viscosity, {zeta} and its ratio with the shear viscosity, {zeta}/{eta} have been studied in an anisotropically expanding pure glue plasma in the presence of turbulent color fields. It has been shown that the anisotropy in the momentum distribution function of gluons, which has been determined from a linearized transport equation eventually leads to the bulk viscosity. For the isotropic (equilibrium) state, a recently proposed quasiparticle model of pure SU(3) lattice QCD equation of state has been employed where the interactions are encoded in the effective fugacity. It has been argued that the interactions present in the equation of state, significantly contribute to the bulk viscosity. Its ratio with the shear viscosity is significant even at 1.5T{sub c}. Thus, one needs to take in account the effects of the bulk viscosity while studying the hydrodynamic expansion of quark-gluon plasma in the Relativistic Heavy Ion Collider and the Large Hadron Collider.

  17. ,"Finished Motor Gasoline Refinery, Bulk Terminal, and Natural...

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

    ,,"(202) 586-8800",,,"1252016 6:37:20 PM" "Back to Contents","Data 1: Finished Motor Gasoline Refinery, Bulk Terminal, and Natural Gas Plant Stocks" "Sourcekey","MGFSXUS1"...

  18. Bulk Energy Storage Webinar Rescheduled for February 9, 2012...

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

    webinar, Lessons from Iowa: The Economic, Market, and Organizational Issues in Making Bulk Energy Storage Work, on Thursday, February 9, 2012 at 1 p.m. ET. Presenters include Dr. ...

  19. The influence of molecular orientation on organic bulk heterojunction solar

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

    cells The influence of molecular orientation on organic bulk heterojunction solar cells The influence of molecular orientation on organic bulk heterojunction solar cells Print Monday, 28 April 2014 09:03 Work done on ALS Beamlines 11.0.1.2, 7.3.3, and 5.3.2.2. reveals that preferential orientation of polymer chains with respect to the fullerene domain leads to a high photovoltaic performance. Featured on the cover of Nature Photonics 8. Article link

  20. Intrinsic carrier multiplication efficiency in bulk Si crystals evaluated

    Office of Scientific and Technical Information (OSTI)

    by optical-pump/terahertz-probe spectroscopy (Journal Article) | SciTech Connect Intrinsic carrier multiplication efficiency in bulk Si crystals evaluated by optical-pump/terahertz-probe spectroscopy Citation Details In-Document Search Title: Intrinsic carrier multiplication efficiency in bulk Si crystals evaluated by optical-pump/terahertz-probe spectroscopy We estimated the carrier multiplication efficiency in the most common solar-cell material, Si, by using optical-pump/terahertz-probe

  1. Linux Kernel Co-Scheduling For Bulk Synchronous Parallel Applications

    Office of Scientific and Technical Information (OSTI)

    (Conference) | SciTech Connect Linux Kernel Co-Scheduling For Bulk Synchronous Parallel Applications Citation Details In-Document Search Title: Linux Kernel Co-Scheduling For Bulk Synchronous Parallel Applications This paper describes a kernel scheduling algorithm that is based on co-scheduling principles and that is intended for parallel applications running on 1000 cores or more where inter-node scalability is key. Experimental results for a Linux implementation on a Cray XT5 machine are

  2. Linux Kernel Co-Scheduling and Bulk Synchronous Parallelism (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect Linux Kernel Co-Scheduling and Bulk Synchronous Parallelism Citation Details In-Document Search Title: Linux Kernel Co-Scheduling and Bulk Synchronous Parallelism This paper describes a kernel scheduling algorithm that is based on coscheduling principles and that is intended for parallel applications running on 1000 cores or more. Experimental results for a Linux implementation on a Cray XT5 machine are presented. The results indicate that Linux is a suitable

  3. Overview of Fraunhofer IPM Activities in High Temperature Bulk Materials

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

    and Device Development | Department of Energy Fraunhofer IPM Activities in High Temperature Bulk Materials and Device Development Overview of Fraunhofer IPM Activities in High Temperature Bulk Materials and Device Development Presentation given at the 2011 Thermoelectrics Applications Workshop including an overview about Fraunhofer IPM, new funding situation in Germany, high temperature material and modules, energy-autarkic sensors, and thermoelectric metrology. PDF icon konig.pdf More

  4. Compositional ordering and stability in nanostructured, bulk thermoelectric alloys.

    SciTech Connect (OSTI)

    Hekmaty, Michelle A.; Faleev, S.; Medlin, Douglas L.; Leonard, F.; Lensch-Falk, J.; Sharma, Peter Anand; Sugar, J. D.

    2009-09-01

    Thermoelectric materials have many applications in the conversion of thermal energy to electrical power and in solid-state cooling. One route to improving thermoelectric energy conversion efficiency in bulk material is to embed nanoscale inclusions. This report summarize key results from a recently completed LDRD project exploring the science underpinning the formation and stability of nanostructures in bulk thermoelectric and the quantitative relationships between such structures and thermoelectric properties.

  5. Enhancing covalent mechanochemistry in bulk polymers using electrospun ABA

    Office of Scientific and Technical Information (OSTI)

    triblock copolymers (Journal Article) | SciTech Connect Enhancing covalent mechanochemistry in bulk polymers using electrospun ABA triblock copolymers Citation Details In-Document Search Title: Enhancing covalent mechanochemistry in bulk polymers using electrospun ABA triblock copolymers Authors: Black Ramirez, A.L. ; Schmitt, A.K. ; Mahanthappa, M.K. ; Craig, S.L. [1] ; Duke) [2] + Show Author Affiliations (UW) ( Publication Date: 2016-01-20 OSTI Identifier: 1235465 Resource Type: Journal

  6. Bulk Electronic Structure of Quasicrystals (Journal Article) | DOE PAGES

    Office of Scientific and Technical Information (OSTI)

    Bulk Electronic Structure of Quasicrystals « Prev Next » Title: Bulk Electronic Structure of Quasicrystals Authors: Nayak, J. ; Maniraj, M. ; Rai, Abhishek ; Singh, Sanjay ; Rajput, Parasmani ; Gloskovskii, A. ; Zegenhagen, J. ; Schlagel, D. L. ; Lograsso, T. A. ; Horn, K. ; Barman, S. R. Publication Date: 2012-11-20 OSTI Identifier: 1101813 Type: Publisher's Accepted Manuscript Journal Name: Physical Review Letters Additional Journal Information: Journal Volume: 109; Journal Issue: 21;

  7. Bulk Electronic Structure of Quasicrystals (Journal Article) | SciTech

    Office of Scientific and Technical Information (OSTI)

    Connect Bulk Electronic Structure of Quasicrystals Citation Details In-Document Search Title: Bulk Electronic Structure of Quasicrystals Authors: Nayak, J. ; Maniraj, M. ; Rai, Abhishek ; Singh, Sanjay ; Rajput, Parasmani ; Gloskovskii, A. ; Zegenhagen, J. ; Schlagel, D. L. ; Lograsso, T. A. ; Horn, K. ; Barman, S. R. Publication Date: 2012-11-20 OSTI Identifier: 1101813 Type: Publisher's Accepted Manuscript Journal Name: Physical Review Letters Additional Journal Information: Journal

  8. Nanostructured High Temperature Bulk Thermoelectric Energy Conversion for

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

    Efficient Waste Heat Recovery | Department of Energy High Temperature Bulk Thermoelectric Energy Conversion for Efficient Waste Heat Recovery Nanostructured High Temperature Bulk Thermoelectric Energy Conversion for Efficient Waste Heat Recovery Proposed two-stage TEG system with half-heusler as the first stage, and Bi2Te3 as the low temperature stage expected to show a 5% fuel efficiency improvement in vehicle platform under US06 drive cycle PDF icon caylor.pdf More Documents &

  9. Nanostructured High-Temperature Bulk Thermoelectric Energy Conversion for

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

    Efficient Automotive Waste Heat Recovery | Department of Energy High-Temperature Bulk Thermoelectric Energy Conversion for Efficient Automotive Waste Heat Recovery Nanostructured High-Temperature Bulk Thermoelectric Energy Conversion for Efficient Automotive Waste Heat Recovery 2012 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting PDF icon ace082_caylor_2012_o.pdf More Documents & Publications Nanostructured High

  10. Reliability of Transport Properties for Bulk Thermoelectrics | Department

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

    of Energy of Transport Properties for Bulk Thermoelectrics Reliability of Transport Properties for Bulk Thermoelectrics Presents international round-robin study to ensure quality of transport data and figure of merit of thermoelectric materials PDF icon deer12_wang_2.pdf More Documents & Publications International Round-Robin on Transport Properties of Bismuth Telluride Thermoelectric Mechanical Reliability Standardization of Transport Properties Measurements: Internal Energy Agency

  11. Development of a Wet Logistics System for Bulk Corn Stover

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

    1000: Development of a Wet Logistics System for Bulk Corn Stover March 25, 2015 Lynn M. Wendt, William A. Smith, Austin Murphy, and Ian J. Bonner Idaho National Laboratory This presentation does not contain any proprietary, confidential, or otherwise restricted information Technology Area Review: Feedstock Supply and Logistics 2 | Bioenergy Technologies Office Overall Project Goal Project Objective * Design a high-moisture, bulk feedstock logistics system that - Reduces the risk of catastrophic

  12. THRESHOLD RADIOACTIVITY FOR BULK FOOD SAMPLES BY GAMMA SPECTROSCOPY

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect THRESHOLD RADIOACTIVITY FOR BULK FOOD SAMPLES BY GAMMA SPECTROSCOPY Citation Details In-Document Search Title: THRESHOLD RADIOACTIVITY FOR BULK FOOD SAMPLES BY GAMMA SPECTROSCOPY Authors: Yakabe, H.M. ; Neilson, H. Publication Date: 1965-02-01 OSTI Identifier: 4654936 Resource Type: Journal Article Resource Relation: Journal Name: J. Assoc. Offic. Agr. Chemists; Journal Volume: Vol: 48; Other Information: Orig. Receipt Date: 31-DEC-65 Research Org: Div. of

  13. Thermoelectric Bulk Materials from the Explosive Consolidation of

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

    Nanopowders | Department of Energy Bulk Materials from the Explosive Consolidation of Nanopowders Thermoelectric Bulk Materials from the Explosive Consolidation of Nanopowders Describes technique of explosively consolidating nanopowders to yield fully dense, consolidated, nanostructured thermoelectric material PDF icon nemir.pdf More Documents & Publications The Bottom-Up Approach forThermoelectric Nanocomposites, plusƒ Enhancing the Figure-of-Merit in Half-Heuslers for Vehicle Waste

  14. Formation of copper-indium-selenide and/or copper-indium-gallium-selenide films from indium selenide and copper selenide precursors

    DOE Patents [OSTI]

    Curtis, Calvin J.; Miedaner, Alexander; Van Hest, Maikel; Ginley, David S.; Nekuda, Jennifer A.

    2011-11-15

    Liquid-based indium selenide and copper selenide precursors, including copper-organoselenides, particulate copper selenide suspensions, copper selenide ethylene diamine in liquid solvent, nanoparticulate indium selenide suspensions, and indium selenide ethylene diamine coordination compounds in solvent, are used to form crystalline copper-indium-selenide, and/or copper indium gallium selenide films (66) on substrates (52).

  15. Waste Form Qualification Compliance Strategy for Bulk Vitrification

    SciTech Connect (OSTI)

    Bagaasen, Larry M.; Westsik, Joseph H.; Brouns, Thomas M.

    2005-01-03

    The Bulk Vitrification System is being pursued to assist in immobilizing the low-activity tank waste from the 53 million gallons of radioactive waste in the 177 underground storage tanks on the Hanford Site. To demonstrate the effectiveness of the bulk vitrification process, a research and development facility known as the Demonstration Bulk Vitrification System (DBVS) is being built to demonstrate the technology. Specific performance requirements for the final packaged bulk vitrification waste form have been identified. In addition to the specific product-performance requirements, performance targets/goals have been identified that are necessary to qualify the waste form but do not lend themselves to specifications that are easily verified through short-term testing. Collectively, these form the product requirements for the DBVS. This waste-form qualification (WFQ) strategy document outlines the general strategies for achieving and demonstrating compliance with the BVS product requirements. The specific objectives of the WFQ activities are discussed, the bulk vitrification process and product control strategy is outlined, and the test strategy to meet the WFQ objectives is described. The DBVS product performance targets/goals and strategies to address those targets/goals are described. The DBVS product-performance requirements are compared to the Waste Treatment and Immobilization Plant immobilized low-activity waste product specifications. The strategies for demonstrating compliance with the bulk vitrification product requirements are presented.

  16. Silicon-doped boron nitride coated fibers in silicon melt infiltrated composites

    DOE Patents [OSTI]

    Corman, Gregory Scot (Ballston Lake, NY); Luthra, Krishan Lal (Schenectady, NY)

    1999-01-01

    A fiber-reinforced silicon--silicon carbide matrix composite having improved oxidation resistance at high temperatures in dry or water-containing environments is produced. The invention also provides a method for protecting the reinforcing fibers in the silicon--silicon carbide matrix composites by coating the fibers with a silicon-doped boron nitride coating.

  17. Silicon-doped boron nitride coated fibers in silicon melt infiltrated composites

    DOE Patents [OSTI]

    Corman, Gregory Scot (Ballston Lake, NY); Luthra, Krishan Lal (Schenectady, NY)

    2002-01-01

    A fiber-reinforced silicon-silicon carbide matrix composite having improved oxidation resistance at high temperatures in dry or water-containing environments is produced. The invention also provides a method for protecting the reinforcing fibers in the silicon-silicon carbide matrix composites by coating the fibers with a silicon-doped boron nitride coating.

  18. Method of chemical vapor deposition of boron nitride using polymeric cyanoborane

    DOE Patents [OSTI]

    Maya, Leon (Oak Ridge, TN)

    1994-01-01

    Polymeric cyanoborane is volatilized, decomposed by thermal or microwave plasma energy, and deposited on a substrate as an amorphous film containing boron, nitrogen and carbon. Residual carbon present in the film is removed by ammonia treatment at an increased temperature, producing an adherent, essentially stoichiometric boron nitride film.

  19. Organic additive systems for spray-drying and dry pressing silicon nitride

    SciTech Connect (OSTI)

    Walker, W.J. Jr.; Reed, J.S.

    1996-06-01

    Silicon nitride granules for dry pressing were prepared by spray-drying slurries containing polyethylene glycol as the primary binder combined with other organic additives. Differences in slurry viscosity, granule character, pressing behavior and green strength were found to depend on the choice of deflocculant.

  20. Method of chemical vapor deposition of boron nitride using polymeric cyanoborane

    DOE Patents [OSTI]

    Maya, L.

    1994-06-14

    Polymeric cyanoborane is volatilized, decomposed by thermal or microwave plasma energy, and deposited on a substrate as an amorphous film containing boron, nitrogen and carbon. Residual carbon present in the film is removed by ammonia treatment at an increased temperature, producing an adherent, essentially stoichiometric boron nitride film. 11 figs.

  1. Preparation of carbon nanoparticles and carbon nitride from high nitrogen compound

    DOE Patents [OSTI]

    Huynh, My Hang V. (Los Alamos, NM); Hiskey, Michael A. (Los Alamos, NM)

    2009-09-01

    The high-nitrogen compound 3,6-di(azido)-1,2,4,5-tetrazine (DiAT) was synthesized by a relatively simple method and used as a precursor for the preparation of carbon nanospheres and nanopolygons, and nitrogen-rich carbon nitrides.

  2. Aluminum nitride transitional layer for reducing dislocation density and cracking of AlGaN epitaxial films

    DOE Patents [OSTI]

    Allerman, Andrew A.; Crawford, Mary H.; Lee, Stephen R.

    2013-01-08

    A denticulated Group III nitride structure that is useful for growing Al.sub.xGa.sub.1-xN to greater thicknesses without cracking and with a greatly reduced threading dislocation (TD) density.

  3. Solar Cells: Spin-Cast Bulk Heterojunction Solar Cells: A Dynamical...

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

    Solar Cells: Spin-Cast Bulk Heterojunction Solar Cells: A Dynamical Investigation Solar Cells: Spin-Cast Bulk Heterojunction Solar Cells: A Dynamical Investigation Print Wednesday,...

  4. 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.

  5. Palladium diffusion into bulk copper via the (100) surface.

    SciTech Connect (OSTI)

    Bussmann, Ezra; Pohl, Karsten; Sun, Jiebing; Kellogg, Gary Lee

    2009-01-01

    Using low-energy electron microscopy, we measure the diffusion of Pd into bulk Cu at the Cu(100) surface. Interdiffusion is tracked by measuring the dissolution of the Cu(100)-c(2 x 2)-Pd surface alloy during annealing (T > 240 C). The activation barrier for Pd diffusion from the surface alloy into the bulk is determined to be (1.8 {+-} 0.6) eV. During annealing, we observe the growth of a new layer of Cu near step edges. Under this new Cu layer, dilute Pd remaining near the surface develops a layered structure similar to the Cu{sub 3}Pd L 1{sub 2} bulk alloy phase.

  6. Properties of Bulk Sintered Silver As a Function of Porosity

    SciTech Connect (OSTI)

    Wereszczak, Andrew A; Vuono, Daniel J; Wang, Hsin; Ferber, Mattison K; Liang, Zhenxian

    2012-06-01

    This report summarizes a study where various properties of bulk-sintered silver were investigated over a range of porosity. This work was conducted within the National Transportation Research Center's Power Device Packaging project that is part of the DOE Vehicle Technologies Advanced Power Electronics and Electric Motors Program. Sintered silver, as an interconnect material in power electronics, inherently has porosity in its produced structure because of the way it is made. Therefore, interest existed in this study to examine if that porosity affected electrical properties, thermal properties, and mechanical properties because any dependencies could affect the intended function (e.g., thermal transfer, mechanical stress relief, etc.) or reliability of that interconnect layer and alter how its performance is modeled. Disks of bulk-sintered silver were fabricated using different starting silver pastes and different sintering conditions to promote different amounts of porosity. Test coupons were harvested out of the disks to measure electrical resistivity and electrical conductivity, thermal conductivity, coefficient of thermal expansion, elastic modulus, Poisson's ratio, and yield stress. The authors fully recognize that the microstructure of processed bulk silver coupons may indeed not be identical to the microstructure produced in thin (20-50 microns) layers of sintered silver. However, measuring these same properties with such a thin actual structure is very difficult, requires very specialized specimen preparation and unique testing instrumentation, is expensive, and has experimental shortfalls of its own, so the authors concluded that the herein measured responses using processed bulk sintered silver coupons would be sufficient to determine acceptable values of those properties. Almost all the investigated properties of bulk sintered silver changed with porosity content within a range of 3-38% porosity. Electrical resistivity, electrical conductivity, thermal conductivity, elastic modulus, Poisson's ratio, and yield stress all depended on the porosity content in bulk-sintered silver. The only investigated property that was independent of porosity in that range was coefficient of thermal expansion.

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

    SciTech Connect (OSTI)

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

    2013-11-11

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

  8. An experiment to test the viability of a gallium-arsenide cathode in a SRF electron gun

    SciTech Connect (OSTI)

    Kewisch,J.; Ben-Zvi, I.; Rao, T.; Burrill, A.; Pate, D.; Wu, Q.; Todd, R.; Wang, E.; Bluem, H.; Holmes, D.; Schultheiss, T.

    2009-05-04

    Strained gallium arsenide cathodes are used in electron guns for the production of polarized electrons. In order to have a sufficient quantum efficiency lifetime of the cathode the vacuum in the gun must be 10{sup -11} Torr or better, so that the cathode is not destroyed by ion back bombardment or through contamination with residual gases. All successful polarized guns are DC guns, because such vacuum levels can not be obtained in normal conducting RF guns. A superconductive RF gun may provide a sufficient vacuum level due to cryo-pumping of the cavity walls. We report on the progress of our experiment to test such a gun with normal GaAs-Cs crystals.

  9. On-Site and Bulk Hydrogen Storage | Department of Energy

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

    Delivery » On-Site and Bulk Hydrogen Storage On-Site and Bulk Hydrogen Storage On-site hydrogen storage is used at central hydrogen production facilities, transport terminals, and end-use locations. Storage options today include insulated liquid tanks and gaseous storage tanks. The four types of common high pressure gaseous storage vessels are shown in the table. Type I All-metal cylinder Type II Load-bearing metal liner hoop wrapped with resin-impregnated continuous filament Type III

  10. High quality boron carbon nitride/ZnO-nanorods p-n heterojunctions based on magnetron sputtered boron carbon nitride films

    SciTech Connect (OSTI)

    Qian, J. C.; Jha, S. K. E-mail: apwjzh@cityu.edu.hk; Wang, B. Q.; Jelenkovi?, E. V.; Bello, I.; Klemberg-Sapieha, J. E.; Martinu, L.; Zhang, W. J. E-mail: apwjzh@cityu.edu.hk

    2014-11-10

    Boron carbon nitride (BCN) films were synthesized on Si (100) and fused silica substrates by radio-frequency magnetron sputtering from a B{sub 4}C target in an Ar/N{sub 2} gas mixture. The BCN films were amorphous, and they exhibited an optical band gap of ?1.0?eV and p-type conductivity. The BCN films were over-coated with ZnO nanorod arrays using hydrothermal synthesis to form BCN/ZnO-nanorods p-n heterojunctions, exhibiting a rectification ratio of 1500 at bias voltages of 5?V.

  11. High-Yield Synthesis of Stoichiometric Boron Nitride Nanostructures

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

    Nocua, José E.; Piazza, Fabrice; Weiner, Brad R.; Morell, Gerardo

    2009-01-01

    Boron nimore » tride (BN) nanostructures are structural analogues of carbon nanostructures but have completely different bonding character and structural defects. They are chemically inert, electrically insulating, and potentially important in mechanical applications that include the strengthening of light structural materials. These applications require the reliable production of bulk amounts of pure BN nanostructures in order to be able to reinforce large quantities of structural materials, hence the need for the development of high-yield synthesis methods of pure BN nanostructures. Using borazine ( B 3 N 3 H 6 ) as chemical precursor and the hot-filament chemical vapor deposition (HFCVD) technique, pure BN nanostructures with cross-sectional sizes ranging between 20 and 50 nm were obtained, including nanoparticles and nanofibers. Their crystalline structure was characterized by (XRD), their morphology and nanostructure was examined by (SEM) and (TEM), while their chemical composition was studied by (EDS), (FTIR), (EELS), and (XPS). Taken altogether, the results indicate that all the material obtained is stoichiometric nanostructured BN with hexagonal and rhombohedral crystalline structure.« less

  12. Ultra-sensitive Hall sensors based on graphene encapsulated in hexagonal boron nitride

    SciTech Connect (OSTI)

    Dauber, Jan; Stampfer, Christoph; Sagade, Abhay A.; Neumaier, Daniel; Oellers, Martin; Watanabe, Kenji; Taniguchi, Takashi

    2015-05-11

    The encapsulation of graphene in hexagonal boron nitride provides graphene on substrate with excellent material quality. Here, we present the fabrication and characterization of Hall sensor elements based on graphene boron nitride heterostructures, where we gain from high mobility and low charge carrier density at room temperature. We show a detailed device characterization including Hall effect measurements under vacuum and ambient conditions. We achieve a current- and voltage-related sensitivity of up to 5700?V/AT and 3?V/VT, respectively, outpacing state-of-the-art silicon and III/V Hall sensor devices. Finally, we extract a magnetic resolution limited by low frequency electric noise of less than 50 nT/?(Hz) making our graphene sensors highly interesting for industrial applications.

  13. Slip casting and green body evaluation of 6% yttria, 2% alumina silicon nitride. Final report

    SciTech Connect (OSTI)

    Quinn, J.

    1991-12-01

    The superior high temperature properties of silicon nitride are well known. It has good strength, excellent high temperature strength, oxidation resistance, and is resistant to thermal shock. These properties make silicon nitride a good choice for many structural ceramics. Additionally, its high thermal conductivity and low dielectric constant make it a possible candidate for electronic substrates. Knowledge in the areas of characterization, machining, and proper firing parameters is growing and crucial to the production of modern ceramics. Such knowledge also makes it increasingly evident that a poor initial green body cannot result in a good final product. Many fabrication problems can be traced back to the processes such as casting and green body preparation and attention is being concentrated in these areas.

  14. Influence of granule character and compaction on the mechanical properties of sintered silicon nitride

    SciTech Connect (OSTI)

    Takahashi, Hideo; Shinohara, Nobuhiro; Uematsu, Keizo; JunIchiro, Tsubaki

    1996-04-01

    The influence of granule character and compaction on the mechanical properties of sintered silicon nitride was studied as a function of the pH of the spray-dry slurry. The character and the compaction behavior of the spray-dried silicon nitride granules considerably affect the mechanical properties of the sintered body. Dense and hard granules resulting from a well-dispersed slurry retained their shape in green compacts and caused numerous pore defects in sintered body. Decreasing the slurry pH to a certain value (e.g., 7.9) caused slurry flocculation and reduced the granule density as well as the diametral compression strength of the granules. Sintered bodies fabricated with these weak granules contained fewer defects and showed remarkable strength increase.

  15. Sandia Energy - Sandia Demonstrated First-Time, Single-Mode Lasing...

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

    Demonstrated First-Time, Single-Mode Lasing in Gallium-Nitride Nanowire Lasers Home Energy Solid-State Lighting Facilities CINT News Energy Efficiency News & Events Research &...

  16. Intrinsic Semiconductor | Open Energy Information

    Open Energy Info (EERE)

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

  17. Cree Inc | Open Energy Information

    Open Energy Info (EERE)

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

  18. Energy Storage Systems 2010 Update Conference Presentations ...

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

    Gallium Nitride Substrates - Karen Waldrip, SNL.pdf More Documents & Publications Energy Storage & Power Electronics 2008 Peer Review - Power Electronics (PE) Systems ...

  19. Synthesis of bulk superhard semiconducting B-C material

    SciTech Connect (OSTI)

    Solozhenko, Vladimir L.; Dubrovinskaia, Natalia A.; Dubrovinsky, Leonid S.

    2004-08-30

    A bulk composite superhard material was synthesized from graphitelike BC{sub 3} at 20 GPa and 2300 K using a multianvil press. The material consists of intergrown boron carbide B{sub 4}C and B-doped diamond with 1.8 at.%B. The material exhibits semiconducting behavior and extreme hardness comparable with that of single-crystal diamond.

  20. Permanent magnet with MgB{sub 2} bulk superconductor

    SciTech Connect (OSTI)

    Yamamoto, Akiyasu, E-mail: yamamoto@appchem.t.u-tokyo.ac.jp [The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656 (Japan); JST-PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Ishihara, Atsushi; Tomita, Masaru [Railway Technical Research Institute, 2-8-38 Hikari, Kokubunji, Tokyo 185-8540 (Japan); Kishio, Kohji [The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656 (Japan)

    2014-07-21

    Superconductors with persistent zero-resistance currents serve as permanent magnets for high-field applications requiring a strong and stable magnetic field, such as magnetic resonance imaging. The recent global helium shortage has quickened research into high-temperature superconductors (HTSs)materials that can be used without conventional liquid-helium cooling to 4.2?K. Herein, we demonstrate that 40-K-class metallic HTS magnesium diboride (MgB{sub 2}) makes an excellent permanent bulk magnet, maintaining 3?T at 20?K for 1 week with an extremely high stability (<0.1 ppm/h). The magnetic field trapped in this magnet is uniformly distributed, as for single-crystalline neodymium-iron-boron. Magnetic hysteresis loop of the MgB{sub 2} permanent bulk magnet was determined. Because MgB{sub 2} is a simple-binary-line compound that does not contain rare-earth metals, polycrystalline bulk material can be industrially fabricated at low cost and with high yield to serve as strong magnets that are compatible with conventional compact cryocoolers, making MgB{sub 2} bulks promising for the next generation of Tesla-class permanent-magnet applications.

  1. Use of free silicon in liquid phase sintering of silicon nitrides and sialons

    DOE Patents [OSTI]

    Raj, Rishi (Ithaca, NY); Baik, Sunggi (Ithaca, NY)

    1985-11-12

    This invention relates to the production of improved high density nitrogen based ceramics by liquid-phase densification of silicon nitride or a compound of silicon-nitrogen-oxygen-metal, e.g. a sialon. In the process and compositions of the invention minor amounts of finely divided silicon are employed together with the conventional liquid phase producing additives to enhance the densification of the resultant ceramic.

  2. Integrated rig for the production of boron nitride nanotubes via the pressurized vapor-condenser method

    DOE Patents [OSTI]

    Smith, Michael W; Jordan, Kevin C

    2014-03-25

    An integrated production apparatus for production of boron nitride nanotubes via the pressure vapor-condenser method. The apparatus comprises: a pressurized reaction chamber containing a continuously fed boron containing target having a boron target tip, a source of pressurized nitrogen and a moving belt condenser apparatus; a hutch chamber proximate the pressurized reaction chamber containing a target feed system and a laser beam and optics.

  3. Use of free silicon in liquid phase sintering of silicon nitrides and sialons

    DOE Patents [OSTI]

    Raj, R.; Baik, S.

    1985-11-12

    This invention relates to the production of improved high density nitrogen based ceramics by liquid-phase densification of silicon nitride or a compound of silicon-nitrogen-oxygen-metal, e.g. a sialon. In the process and compositions of the invention minor amounts of finely divided silicon are employed together with the conventional liquid phase producing additives to enhance the densification of the resultant ceramic. 4 figs.

  4. 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.

  5. Boron-Nitride (BN) Nanotubes (BNNT) at TJNAF| U.S. DOE Office of Science

    Office of Science (SC) Website

    (SC) Boron-Nitride (BN) Nanotubes (BNNT) at TJNAF Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Applications of Nuclear Science Applications of Nuclear Science Archives Small Business Innovation / Technology Transfer Funding Opportunities Nuclear Science Advisory Committee (NSAC) Community Resources Contact Information Nuclear Physics U.S. Department of Energy SC-26/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301)

  6. A COMPREHENSIVE TECHNICAL REVIEW OF THE DEMONSTRATION BULK VITRIFICATION SYSTEM

    SciTech Connect (OSTI)

    SCHAUS, P.S.

    2006-09-29

    In May 2006, CH2M Hill Hanford Group, Inc. chartered an Expert Review Panel (ERP) to review the current status of the Demonstration Bulk Vitrification System (DBVS). It is the consensus of the ERP that bulk vitrification is a technology that requires further development and evaluation to determine its potential for meeting the Hanford waste stabilization mission. No fatal flaws (issues that would jeopardize the overall DBVS mission that cannot be mitigated) were found, given the current state of the project. However, a number of technical issues were found that could significantly affect the project's ability to meet its overall mission as stated in the project ''Justification of Mission Need'' document, if not satisfactorily resolved. The ERP recognizes that the project has changed from an accelerated schedule demonstration project to a formally chartered project that must be in full compliance with DOE 413.3 requirements. The perspective of the ERP presented herein, is measured against the formally chartered project as stated in the approved Justification of Mission Need document. A justification of Mission Need document was approved in July 2006 which defined the objectives for the DBVS Project. In this document, DOE concluded that bulk vitrification is a viable technology that requires additional development to determine its potential applicability to treatment of a portion of the Hanford low activity waste. The DBVS mission need statement now includes the following primary objectives: (1) process approximately 190,000 gallons of Tank S-109 waste into fifty 100 metric ton boxes of vitrified product; (2) store and dispose of these boxes at Hanford's Integrated Disposal Facility (IDF); (3) evaluate the waste form characteristics; (4) gather pilot plant operability data, and (5) develop the overall life cycle system performance of bulk vitrification and produce a comparison of the bulk vitrification process to building a second LAW Immobilization facility or other supplemental treatment alternatives as provided in M-62-08.

  7. MOCVD synthesis of group III-nitride heterostructure nanowires for solid-state lighting.

    SciTech Connect (OSTI)

    Wang, George T.; Creighton, James Randall; Talin, Albert Alec

    2006-11-01

    Solid-state lighting (SSL) technologies, based on semiconductor light emitting devices, have the potential to reduce worldwide electricity consumption by more than 10%, which could significantly reduce U.S. dependence on imported energy and improve energy security. The III-nitride (AlGaInN) materials system forms the foundation for white SSL and could cover a wide spectral range from the deep UV to the infrared. For this LDRD program, we have investigated the synthesis of single-crystalline III-nitride nanowires and heterostructure nanowires, which may possess unique optoelectronic properties. These novel structures could ultimately lead to the development of novel and highly efficient SSL nanodevice applications. GaN and III-nitride core-shell heterostructure nanowires were successfully synthesized by metal organic chemical vapor deposition (MOCVD) on two-inch wafer substrates. The effect of process conditions on nanowire growth was investigated, and characterization of the structural, optical, and electrical properties of the nanowires was also performed.

  8. Non-Destructive Spent Fuel Characterization with Semi-Conducting Gallium Arsinde Neutron Imaging Arrays

    SciTech Connect (OSTI)

    Douglas S. McGregor; Holly K. Gersch; Jeffrey D. Sanders; John C. Lee; Mark D. Hammig; Michael R. Hartman; Yong Hong Yang; Raymond T. Klann; Brian Van Der Elzen; John T. Lindsay; Philip A. Simpson

    2002-01-30

    High resistivity bulk grown GaAs has been used to produce thermal neutron imaging devices for use in neutron radiography and characterizing burnup in spent fuel. The basic scheme utilizes a portable Sb/Be source for monoenergetic (24 keV) neutron radiation source coupled to an Fe filter with a radiation hard B-coated pixellated GaAs detector array as the primary neutron detector. The coated neutron detectors have been tested for efficiency and radiation hardness in order to determine their fitness for the harsh environments imposed by spent fuel. Theoretical and experimental results are presented, showing detector radiation hardness, expected detection efficiency and the spatial resolution from such a scheme. A variety of advanced neutron detector designs have been explored, with experimental results achieving 13% thermal neutron detection efficiency while projecting the possibility of over 30% thermal neutron detection efficiency.

  9. GaN-Ready Aluminum Nitride Substrates for Cost-Effective, Very Low Dislocation Density III-Nitride LED's

    SciTech Connect (OSTI)

    Sandra Schujman; Leo Schowalter

    2010-10-15

    The objective of this project was to develop and then demonstrate the efficacy of a costeffective approach for a low defect density substrate on which AlInGaN LEDs can be fabricated. The efficacy of this GaN-ready substrate would then be tested by growing high efficiency, long lifetime InxGa1-xN blue LEDs. The approach used to meet the project objectives was to start with low dislocation density AlN single-crystal substrates and grow graded AlxGa1-xN layers on top. Pseudomorphic AlxGa1-xN epitaxial layers grown on bulk AlN substrates were used to fabricate light emitting diodes and demonstrate better device performance as a result of the low defect density in these layers when benched marked against state-of-the-art LEDs fabricated on sapphire substrates. The pseudomorphic LEDs showed excellent output powers compared to similar wavelength devices grown on sapphire substrates, with lifetimes exceeding 10,000 hours (which was the longest time that could reliably be estimated). In addition, high internal quantum efficiencies were demonstrated at high driving current densities even though the external quantum efficiencies were low due to poor photon extraction. Unfortunately, these pseudomorphic LEDs require high Al content so they emit in the ultraviolet. Sapphire based LEDs typically have threading dislocation densities (TDD) > 108 cm-2 while the pseudomorphic LEDs have TDD ? 105 cm-2. The resulting TDD, when grading the AlxGa1-xN layer all the way to pure GaN to produce a GaN-ready substrate, has varied between the mid 108 down to the 106 cm-2. These inconsistencies are not well understood. Finally, an approach to improve the LED structures on AlN substrates for light extraction efficiency was developed by thinning and roughening the substrate.

  10. Analysis of 1w Bulk Laser Damage in KDP

    SciTech Connect (OSTI)

    Cross, D A; Carr, C W

    2011-04-11

    The influence of laser parameters on laser-induced damage in the bulk of KDP is difficult to determine because the damage manifests as discrete sites a few microns in diameter distributed throughout a relatively large volume of material. Here, they present a method to directly measure the size and location of many thousands of such sites and correlate them to the laser conditions which produced them. This technique is used to characterize the effects of pulse duration on damage initiated by 1053 nm light in the bulk of KDP crystals. They find that the density of damage sites produced by 1053 nm light is less sensitive to pulse duration than was previously reported for 526 nm and 351 nm light. In addition, the effect of pulse duration on the size of the damage sites produced appears insensitive to wavelength.

  11. Method of fabricating an optoelectronic device having a bulk heterojunction

    DOE Patents [OSTI]

    Shtein, Max (Ann Arbor, MI); Yang, Fan (Princeton, NJ); Forrest, Stephen R. (Princeton, NJ)

    2008-10-14

    A method of fabricating an optoelectronic device comprises: depositing a first layer having protrusions over a first electrode, in which the first layer comprises a first organic small molecule material; depositing a second layer on the first layer such that the second layer is in physical contact with the first layer; in which the smallest lateral dimension of the protrusions are between 1 to 5 times the exciton diffusion length of the first organic small molecule material; and depositing a second electrode over the second layer to form the optoelectronic device. A method of fabricating an organic optoelectronic device having a bulk heterojunction is also provided and comprises: depositing a first layer with protrusions over an electrode by organic vapor phase deposition; depositing a second layer on the first layer where the interface of the first and second layers forms a bulk heterojunction; and depositing another electrode over the second layer.

  12. Power mixture and green body for producing silicon nitride base articles of high fracture toughness and strength

    DOE Patents [OSTI]

    Huckabee, M.L.; Buljan, S.T.; Neil, J.T.

    1991-09-17

    A powder mixture and a green body for producing a silicon nitride-based article of improved fracture toughness and strength are disclosed. The powder mixture includes (a) a bimodal silicon nitride powder blend consisting essentially of about 10-30% by weight of a first silicon nitride powder of an average particle size of about 0.2 [mu]m and a surface area of about 8-12m[sup 2]g, and about 70-90% by weight of a second silicon nitride powder of an average particle size of about 0.4-0.6 [mu]m and a surface area of about 2-4 m[sup 2]/g, (b) about 10-50 percent by volume, based on the volume of the densified article, of refractory whiskers or fibers having an aspect ratio of about 3-150 and having an equivalent diameter selected to produce in the densified article an equivalent diameter ratio of the whiskers or fibers to grains of silicon nitride of greater than 1.0, and (c) an effective amount of a suitable oxide densification aid. The green body is formed from the powder mixture, an effective amount of a suitable oxide densification aid, and an effective amount of a suitable organic binder. No Drawings

  13. Dynamics of dendritic polymers in the bulk and under confinement

    SciTech Connect (OSTI)

    Chrissopoulou, K.; Fotiadou, S.; Androulaki, K.; Anastasiadis, S. H.; Tanis, I.; Karatasos, K.; Prevosto, D.; Labardi, M.; Frick, B.

    2014-05-15

    The structure and dynamics of a hyperbranched polyesteramide (Hybrane S 1200) polymer and its nanocomposites with natural montmorillonite (Na{sup +}-MMT) are investigated by XRD, DSC, QENS, DS and Molecular Dynamics (MD) simulation. In bulk, the energy-resolved elastically scattered intensity from the polymer exhibits two relaxation steps, one attributed to sub-T{sub g} motions and one observed at temperatures above the glass transition, T{sub g}. The QENS spectra measured over the complete temperature range are consistent with the elastic measurements and can be correlated to the results emerging from the detailed description afforded by the atomistic simulations, which predict the existence of three relaxation processes. Moreover, dielectric spectroscopy shows the sub- T{sub g} beta process as well as the segmental relaxation. For the nanocomposites, XRD reveals an intercalated structure for all hybrids with distinct interlayer distances due to polymer chains residing within the galleries of the Na{sup +}-MMT. The polymer chains confined within the galleries show similarities in the behavior with that of the polymer in the bulk for temperatures below the bulk polymer T{sub g}, whereas they exhibit frozen dynamics under confinement at temperatures higher than that.

  14. Process for the production of hydrogen and carbonyl sulfide from hydrogen sulfide and carbon monoxide using a metal boride, nitride, carbide and/or silicide catalyst

    SciTech Connect (OSTI)

    McGuiggan, M.F.; Kuch, P.L.

    1984-05-08

    Hydrogen and carbonyl sulfide are produced by a process comprising contacting gaseous hydrogen sulfide with gaseous carbon monoxide in the presence of a metal boride, carbide, nitride and/or silicide catalyst, such as titanium carbide, vanadium boride, manganese nitride or molybdenum silicide.

  15. The development of a porous silicon nitride crossflow filter; Final report, September 1988--September 1992

    SciTech Connect (OSTI)

    1992-09-01

    This report summarizes the work performed in developing a permeable form of silicon nitride for application to ceramic crossflow filters for use in advanced coal-fired electric power plants. The program was sponsored by the Department of Energy Morgantown Energy Technology Center and consisted of a design analysis and material development phase and a filter manufacture and demonstration phase. The crossflow filter design and operating requirements were defined. A filter design meeting the requirements was developed and thermal and stress analyses were performed. Material development efforts focused initially on reaction-bonded silicon nitride material. This approach was not successful, and the materials effort was refocused on the development of a permeable form of sintered silicon nitride (SSN). This effort was successful. The SSN material was used for the second phase of the program, filter manufacture and evaluation. Four half-scale SAN filter modules were fabricated. Three of the modules were qualified for filter performance tests. Tests were performed on two of the three qualified modules in the High-Temperature, High-Pressure facility at the Westinghouse Science and Technology Center. The first module failed on test when it expanded into the clamping device, causing dust leakage through the filter. The second module performed well for a cumulative 150-hr test. It displayed excellent filtration capability during the test. The blowback pulse cleaning was highly effective, and the module apparently withstood the stresses induced by the periodic pulse cleaning. Testing of the module resumed, and when the flow of combustion gas through the filter was doubled, cracks developed and the test was concluded.

  16. Strength and fatigue of NT551 silicon nitride and NT551 diesel exhaust valves

    SciTech Connect (OSTI)

    Andrews, M.J.; Werezczak, A.A.; Kirkland, T.P.; Breder, K.

    2000-02-01

    The content of this report is excerpted from Mark Andrew's Ph.D. Thesis (Andrews, 1999), which was funded by a DOE/OTT High Temperature Materials Laboratory Graduate Fellowship. It involves the characterization of NT551 and valves fabricated with it. The motivations behind using silicon nitride (Si{sub 3}N{sub 4}) as an exhaust valve for a diesel engine are presented in this section. There are several economic factors that have encouraged the design and implementation of ceramic components for internal combustion (IC) engines. The reasons for selecting the diesel engine valve for this are also presented.

  17. Recent progress in the morphology of bulk heterojunction photovoltaics

    SciTech Connect (OSTI)

    Brady, Michael A.; Su, Gregory M.; Chabinyc, Michael L.

    2011-10-06

    A review of current research in the characterization of the morphology of semiconducting polymer:fullerene bulk heterojunctions (BHJs) is presented. BHJs are complex blends of polymers and fullerenes with nanostructures that are highly dependent on materials, processing conditions, and post-treatments to films. Recent work on the study of the morphology of BHJs is surveyed. Emphasis is placed on emerging work on BHJs of poly(3-hexylthiophene), P3HT, and [6,6]-phenyl-C61-butyric acid methyl ester, PCBM, along with BHJs of donoracceptor polymers that have high power conversion efficiency.

  18. Radiative cooling of bulk silicon by incoherent light pump

    SciTech Connect (OSTI)

    Malyutenko, V. K. Bogatyrenko, V. V.; Malyutenko, O. Yu.

    2013-12-23

    In contrast to radiative cooling by light up conversion caused exclusively by a low-entropy laser pump and employing thermally assisted fluorescence/luminescence as a power out, we demonstrate light down conversion cooling by incoherent pumps, 0.470.94??m light emitting diodes, and employing thermal emission (TE) as a power out. We demonstrate ?3.5?K bulk cooling of Si at 450?K because overall energy of multiple below bandgap TE photons exceeds the energy of a single above bandgap pump photon. We show that using large entropy TE as power out helps avoid careful tuning of an incoherent pump wavelength and cool indirect-bandgap semiconductors.

  19. Neutron interaction and their transport with bulk materials

    SciTech Connect (OSTI)

    Rani, Esther Kalpana; Radhika, K.

    2015-05-15

    In the current paper an attempt was made to study and provide fundamental information about neutron interactions that are important to nuclear material measurements. The application of this study is explained about macroscopic interactions with bulk compound materials through a program in DEV C++ language which is done by enabling interaction of neutrons in nature. The output of the entire process depends upon the random number (i.e., incident neutron number), thickness of the material and mean free path as input parameters. Further the current study emphasizes on the usage of materials in shielding.

  20. Comment on ""bulk-plasmon contribution to the work function of...

    Office of Scientific and Technical Information (OSTI)

    Comment on ""bulk-plasmon contribution to the work function of metals Citation Details In-Document Search Title: Comment on ""bulk-plasmon contribution to the work function of...

  1. Development of a Bulk-Format System to Harvest, Handle, Store...

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

    a Bulk-Format System to Harvest, Handle, Store, and Deliver High-Tonnage generaprojectabstract1.pdf More Documents & Publications Development of a Bulk-Format System to Harvest,...

  2. File:08COaBulkTransmissionSitingProcess.pdf | Open Energy Information

    Open Energy Info (EERE)

    8COaBulkTransmissionSitingProcess.pdf Jump to: navigation, search File File history File usage Metadata File:08COaBulkTransmissionSitingProcess.pdf Size of this preview: 463 599...

  3. Strategies for High Thermoelectric zT in Bulk Materials | Department of

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

    Energy High Thermoelectric zT in Bulk Materials Strategies for High Thermoelectric zT in Bulk Materials Zintl principle in chemistry, complex electronic band structures, and incorporation of nanometer sized particles were used to explore, optimize and improve bulk thermoelectric materials PDF icon snyder.pdf More Documents & Publications Strategies for High Thermoelectric zT in Bulk Materials Glass-like thermal conductivity in high efficiency thermoelectric materials Thermoelectric

  4. Powder metallurgy processing and deformation characteristics of bulk multimodal nickel

    SciTech Connect (OSTI)

    Farbaniec, L.; Dirras, G.; Krawczynska, A.; Mompiou, F.; Couque, H.; Naimi, F.; Bernard, F.; Tingaud, D.

    2014-08-15

    Spark plasma sintering was used to process bulk nickel samples from a blend of three powder types. The resulting multimodal microstructure was made of coarse (average size ? 135 ?m) spherical microcrystalline entities (the core) surrounded by a fine-grained matrix (average grain size ? 1.5 ?m) or a thick rim (the shell) distinguishable from the matrix. Tensile tests revealed yield strength of ? 470 MPa that was accompanied by limited ductility (? 2.8% plastic strain). Microstructure observation after testing showed debonding at interfaces between the matrix and the coarse entities, but in many instances, shallow dimples within the rim were observed indicating local ductile events in the shell. Dislocation emission and annihilation at grain boundaries and twinning at crack tip were the main deformation mechanisms taking place within the fine-grained matrix as revealed by in-situ transmission electron microscopy. Estimation of the stress from loop's curvature and dislocation pile-up indicates that dislocation emission from grain boundaries and grain boundary overcoming largely contributes to the flow stress. - Highlights: Bulk multi-modal Ni was processed by SPS from a powder blend. Ultrafine-grained matrix or rim observed around spherical microcrystalline entities Yield strength (470 MPa) and ductility (2.8% plastic strain) were measured. Debonding was found at the matrix/microcrystalline entity interfaces. In-situ TEM showed twinning, dislocation emission and annihilation at grain boundaries.

  5. Method of fabricating an optoelectronic device having a bulk heterojunction

    DOE Patents [OSTI]

    Shtein, Max (Princeton, NJ); Yang, Fan (Princeton, NJ); Forrest, Stephen R. (Princeton, NJ)

    2008-09-02

    A method of fabricating an organic optoelectronic device having a bulk heterojunction comprises the steps of: depositing a first layer over a first electrode by organic vapor phase deposition, wherein the first layer comprises a first organic small molecule material; depositing a second layer on the first layer such that the second layer is in physical contact with the first layer, wherein the interface of the second layer on the first layer forms a bulk heterojunction; and depositing a second electrode over the second layer to form the optoelectronic device. In another embodiment, a first layer having protrusions is deposited over the first electrode, wherein the first layer comprises a first organic small molecule material. For example, when the first layer is an electron donor layer, the first electrode is an anode, the second layer is an electron acceptor layer, and the second electrode is a cathode. As a further example, when the first layer is an electron acceptor layer, the first electrode is a cathode, the second layer is an electron donor layer, and the second electrode is an anode.

  6. Growth and magnetic property of antiperovskite manganese nitride films doped with Cu by molecular beam epitaxy

    SciTech Connect (OSTI)

    Yu, Fengmei; Ren, Lizhu; Meng, Meng; Wang, Yunjia; Yang, Mei; Wu, Shuxiang; Li, Shuwei

    2014-04-07

    Manganese nitrides thin films on MgO (100) substrates with and without Cu-doping have been fabricated by plasma assisted molecular beam epitaxy. Antiperovskite compounds Mn{sub 3.6}Cu{sub 0.4}N have been grown in the case of Cu-doping, and the pure Mn{sub 3}N{sub 2} single crystal has been obtained without Cu-doping. The Mn{sub 3.6}Cu{sub 0.4}N exhibits ferrimagnetism, and the magnetization of Mn{sub 3.6}Cu{sub 0.4}N increases upon the temperature decreasing from 300 K to 5 K, similar to Mn{sub 4}N. The exchange bias (EB) effects emerge in the Mn{sub 3.6}Cu{sub 0.4}N films. The EB behavior is originated from the interfaces between ferrimagnetic Mn{sub 3.6}Cu{sub 0.4}N and antiferromagnetic metal Mn, which is verified to be formed by the data of x-ray photoelectron spectroscopy. The present results not only provide a strategy for producing functional antiperovskite manganese nitrides, but also shed promising light on fabricating the exchange bias part of spintronic devices.

  7. Electron trap level of hydrogen incorporated nitrogen vacancies in silicon nitride

    SciTech Connect (OSTI)

    Sonoda, Ken'ichiro Tsukuda, Eiji; Tanizawa, Motoaki; Yamaguchi, Yasuo

    2015-03-14

    Hydrogen incorporation into nitrogen vacancies in silicon nitride and its effects on electron trap level are analyzed using simulation based on density functional theory with temperature- and pressure-dependent hydrogen chemical potential. If the silicon dangling bonds around a nitrogen vacancy are well separated each other, hydrogen incorporation is energetically stable up to 900?C, which is in agreement with the experimentally observed desorption temperature. On the other hand, if the dangling bonds strongly interact, the incorporation is energetically unfavorable even at room temperature because of steric hindrance. An electron trap level caused by a nitrogen vacancy becomes shallow by the hydrogen incorporation. An electron is trapped in a deep level created by a silicon dangling bond before hydrogen incorporation, whereas it is trapped in a shallow level created by an anti-bonding state of a silicon-silicon bond after hydrogen incorporation. The simulation results qualitatively explain the experiment, in which reduced hydrogen content in silicon nitride shows superior charge retention characteristics.

  8. Power mixture and green body for producing silicon nitride base & articles of high fracture toughness and strength

    DOE Patents [OSTI]

    Huckabee, Marvin L. (Marlboro, MA); Buljan, Sergej-Tomislav (Acton, MA); Neil, Jeffrey T. (Acton, MA)

    1991-01-01

    A powder mixture and a green body for producing a silicon nitride-based article of improved fracture toughness and strength. The powder mixture includes 9a) a bimodal silicon nitride powder blend consisting essentially of about 10-30% by weight of a first silicon mitride powder of an average particle size of about 0.2 .mu.m and a surface area of about 8-12m.sup.2 g, and about 70-90% by weight of a second silicon nitride powder of an average particle size of about 0.4-0.6 .mu.m and a surface area of about 2-4 m.sup.2 /g, (b) about 10-50 percent by volume, based on the volume of the densified article, of refractory whiskers or fibers having an aspect ratio of about 3-150 and having an equivalent diameter selected to produce in the densified articel an equivalent diameter ratio of the whiskers or fibers to grains of silicon nitride of greater than 1.0, and (c) an effective amount of a suitable oxide densification aid. The green body is formed from the powder mixture, an effective amount of a suitable oxide densification aid, and an effective amount of a suitable organic binder.

  9. CX-010895: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

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

  10. Corrosion of Metal Inclusions In Bulk Vitrification Waste Packages

    SciTech Connect (OSTI)

    Bacon, Diana H.; Pierce, Eric M.; Wellman, Dawn M.; Strachan, Denis M.; Josephson, Gary B.

    2006-07-31

    The primary purpose of the work reported here is to analyze the potential effect of the release of technetium (Tc) from metal inclusions in bulk vitrification waste packages once they are placed in the Integrated Disposal Facility (IDF). As part of the strategy for immobilizing waste from the underground tanks at Hanford, selected wastes will be immobilized using bulk vitrification. During analyses of the glass produced in engineering-scale tests, metal inclusions were found in the glass product. This report contains the results from experiments designed to quantify the corrosion rates of metal inclusions found in the glass product from AMEC Test ES-32B and simulations designed to compare the rate of Tc release from the metal inclusions to the release of Tc from glass produced with the bulk vitrification process. In the simulations, the Tc in the metal inclusions was assumed to be released congruently during metal corrosion as soluble TcO4-. The experimental results and modeling calculations show that the metal corrosion rate will, under all conceivable conditions at the IDF, be dominated by the presence of the passivating layer and corrosion products on the metal particles. As a result, the release of Tc from the metal particles at the surfaces of fractures in the glass releases at a rate similar to the Tc present as a soluble salt. The release of the remaining Tc in the metal is controlled by the dissolution of the glass matrix. To summarize, the release of 99Tc from the BV glass within precipitated Fe is directly proportional to the diameter of the Fe particles and to the amount of precipitated Fe. However, the main contribution to the Tc release from the iron particles is over the same time period as the release of the soluble Tc salt. For the base case used in this study (0.48 mass% of 0.5 mm diameter metal particles homogeneously distributed in the BV glass), the release of 99Tc from the metal is approximately the same as the release from 0.3 mass% soluble Tc salt in the castable refractory block and it is released over the same time period as the salt. Therefore, to limit the impact of precipitated Fe on the release of 99Tc, both the amount of precipitated Fe in the BV glass and the diameter of these particles should be minimized.

  11. EIA Open Data - Bulk - U.S. Energy Information Administration (EIA)

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

    Bulk download facility The bulk download facility provides the entire contents of each major API data set in a single ZIP file. A small JSON formatted manifest file lists the bulk files and the update date of each file. The manifest is generally updated daily and can be downloaded from http://api.eia.gov/bulk/manifest.txt. The manifest contains information about the bulk files, including all required common core attributes: identifier data_set last_updated modified category_id title description

  12. Coherent rho 0 photoproduction in bulk matter at high energies

    SciTech Connect (OSTI)

    Couderc, Elsa; Klein, Spencer

    2009-01-09

    The momentum transfer {Delta}k required for a photon to scatter from a target and emerge as a {rho}{sup 0} decreases as the photon energy k rises. For k > 3 x 10{sup 14} eV, {Delta}k is small enough that the interaction cannot be localized to a single nucleus. At still higher energies, photons may coherently scatter elastically from bulk matter and emerge as a {rho}{sup 0}, in a manner akin to kaon regeneration. Constructive interference from the different nuclei coherently raises the cross section and the interaction probability rises linearly with energy. At energies above 10{sup 23} eV, coherent conversion is the dominant process; photons interact predominantly as {rho}{sup 0}. We compute the coherent scattering probabilities in slabs of lead, water and rock, and discuss the implications of the increased hadronic interaction probabilities for photons on ultra-high energy shower development.

  13. Interaction of graphene quantum dots with bulk semiconductor surfaces

    SciTech Connect (OSTI)

    Mohapatra, P. K.; Singh, B. P.; Kushavah, Dushyant; Mohapatra, J.

    2015-05-15

    Highly luminescent graphene quantum dots (GQDs) are synthesized through thermolysis of glucose. The average lateral size of the synthesized GQDs is found to be ?5 nm. The occurrence of D and G band at 1345 and 1580 cm{sup ?1} in Raman spectrum confirms the presence of graphene layers. GQDs are mostly consisting of 3 to 4 graphene layers as confirmed from the AFM measurements. Photoluminescence (PL) measurement shows a distinct broadening of the spectrum when GQDs are on the semiconducting bulk surface compared to GQDs in water. The time resolved PL measurement shows a significant shortening in PL lifetime due to the substrate interaction on GQDs compared to the GQDs in solution phase.

  14. FINITE ELEMENT ANALYSIS OF BULK TRITIUM SHIPPING PACKAGE

    SciTech Connect (OSTI)

    Jordan, J.

    2010-06-02

    The Bulk Tritium Shipping Package was designed by Savannah River National Laboratory. This package will be used to transport tritium. As part of the requirements for certification, the package must be shown to meet the scenarios of the Hypothetical Accident Conditions (HAC) defined in Code of Federal Regulations Title 10 Part 71 (10CFR71). The conditions include a sequential 30-foot drop event, 30-foot dynamic crush event, and a 40-inch puncture event. Finite Element analyses were performed to support and expand upon prototype testing. Cases similar to the tests were evaluated. Additional temperatures and orientations were also examined to determine their impact on the results. The peak stress on the package was shown to be acceptable. In addition, the strain on the outer drum as well as the inner containment boundary was shown to be acceptable. In conjunction with the prototype tests, the package was shown to meet its confinement requirements.

  15. Methods of synthesizing hydroxyapatite powders and bulk materials

    DOE Patents [OSTI]

    Luo, P.

    1999-01-12

    Methods are provided for producing non-porous controlled morphology hydroxyapatite granules of less than 8 {micro}m by a spray-drying process. Solid or hollow spheres or doughnuts can be formed by controlling the volume fraction and viscosity of the slurry as well as the spray-drying conditions. Methods of providing for homogeneous cellular structure hydroxyapatite granules are also provided. Pores or channels or varying size and number can be formed by varying the temperature at which a hydroxyapatite slurry formed in basic, saturated ammonium hydroxide is spray-dried. Methods of providing non-porous controlled morphology hydroxyapatite granules in ammonium hydroxide are also provided. The hydroxyapatite granules and bulk materials formed by these methods are also provided. 26 figs.

  16. Methods of synthesizing hydroxyapatite powders and bulk materials

    DOE Patents [OSTI]

    Luo, Ping (2843A Forest Ave., Berkeley, CA 94705)

    1999-01-12

    Methods are provided for producing non-porous controlled morphology hydroxyapatite granules of less than 8 .mu.m by a spray-drying process. Solid or hollow spheres or doughnuts can be formed by controlling the volume fraction and viscosity of the slurry as well as the spray-drying conditions. Methods of providing for homogenous cellular structure hydroxyapatite granules are also provided. Pores or channels or varying size and number can be formed by varying the temperature at which a hydroxyapatite slurry formed in basic, saturated ammonium hydroxide is spray-dried. Methods of providing non-porous controlled morphology hydroxyapatite granules in ammonium hydroxide are also provided. The hydroxyapatite granules and bulk materials formed by these methods are also provided.

  17. FY07 LDRD Final Report Synthesis under High Pressure and Temperature of New Metal Nitrides

    SciTech Connect (OSTI)

    Crowhurst, J C; Sadigh, B; Aberg, D; Zaug, J M; Goncharov, A F

    2008-09-23

    The original aim of this LDRD was to determine with unprecedented precision the melting curve of iron to geophysically relevant pressures. In the course of developing much of the technology and techniques required to obtain this information we have encountered and studied novel chemical reactions some of whose products are stable or metastable under ambient conditions. Specifically we have synthesized nitrides of the platinum group metals including platinum, iridium, and palladium. We have also carried out in depth first principles theoretical investigations into the nature of these materials. We believed that the scientific impact of continuing this work would be greater than that of the original goals of this project. Indeed the work has led to a number of high profile publications with additional publications in preparation. While nitrides of the transition metals are generally of tremendous technological importance, those of the noble metals in particular have enjoyed much experimental and theoretical attention in the very short time since they were first synthesized. The field was and clearly remains open for further study. While the scientific motivation for this research is different from that originally proposed, many of the associated methods in which we have now gained experience are similar or identical. These include use of the diamond anvil cell combined with technologies to generate high temperatures, the in-situ technique of Raman scattering using our purpose-built, state-of-the-art system, analytical techniques for determining the composition of recovered samples such as x-ray photoelectron spectroscopy, and finally synchrotron-based techniques such as x-ray diffraction for structural and equation of state determinations. Close interactions between theorists and experimentalists has and will continue to allow our group to rapidly and reliably interpret complicated results on the structure and dynamics of these compounds and also additional novel materials. Although the purely scientific dividends of this project have been substantial, there remains the possibility of a technological application--now that nitrides with likely desirable properties have been shown to exist, large-scale synthesis techniques can be considered.

  18. Analysis of Nitrogen Incorporation in Group III-Nitride-Arsenide Materials Using a Magnetic Sector Secondary-Ion Mass Spectrometry (SIMS) Instrument: Preprint

    SciTech Connect (OSTI)

    Reedy, R. C.; Geisz, J. F.; Kurtz, S. R.; Adams, R. O.; Perkins, C. L.

    2001-10-01

    Presented at the 2001 NCPV Program Review Meeting: Group III-nitride-arsenide materials were studied by SIMS, XRD, and Profiler to determine small amounts of nitrogen that can lower the alloys bandgap significantly.

  19. Steel bonded dense silicon nitride compositions and method for their fabrication

    DOE Patents [OSTI]

    Landingham, R.L.; Shell, T.E.

    1985-05-20

    A two-stage bonding technique for bonding high density silicon nitride and other ceramic materials to stainless steel and other hard metals, and multilayered ceramic-metal composites prepared by the technique are disclosed. The technique involves initially slurry coating a surface of the ceramic material at about 1500/sup 0/C in a vacuum with a refractory material and the stainless steel is then pressure bonded to the metallic coated surface by brazing it with nickel-copper-silver or nickel-copper-manganese alloys at a temperature in the range of about 850/sup 0/ to 950/sup 0/C in a vacuum. The two-stage bonding technique minimizes the temperature-expansion mismatch between the dissimilar materials.

  20. A cohesive law for interfaces in graphene/hexagonal boron nitride heterostructure

    SciTech Connect (OSTI)

    Zhang, Chenxi; Lou, Jun; Song, Jizhou

    2014-04-14

    Graphene/hexagonal boron nitride (h-BN) heterostructure has showed great potential to improve the performance of graphene device. We have established the cohesive law for interfaces between graphene and monolayer or multi-layer h-BN based on the van der Waals force. The cohesive energy and cohesive strength are given in terms of area density of atoms on corresponding layers, number of layers, and parameters in the van der Waals force. It is found that the cohesive law in the graphene/multi-layer h-BN is dominated by the three h-BN layers which are closest to the graphene. The approximate solution is also obtained to simplify the expression of cohesive law. These results are very useful to study the deformation of graphene/h-BN heterostructure, which may have significant impacts on the performance and reliability of the graphene devices especially in the areas of emerging applications such as stretchable electronics.

  1. The interaction between hexagonal boron nitride and water from first principles

    SciTech Connect (OSTI)

    Wu, Yanbin; Aluru, Narayana R.; Wagner, Lucas K.

    2015-06-21

    The use of hexagonal boron nitride (h-BN) in microfluidic and nanofluidic applications requires a fundamental understanding of the interaction between water and the h-BN surface. A crucial component of the interaction is the binding energy, which is sensitive to the treatment of electron correlation. In this work, we use state of the art quantum Monte Carlo and quantum chemistry techniques to compute the binding energy. Compared to high-level many-body theory, we found that the second-order Mller-Plesset perturbation theory captures the interaction accurately and can thus be used to develop force field parameters between h-BN and water for use in atomic scale simulations. On the contrary, density functional theory with standard dispersion corrections tends to overestimate the binding energy by approximately 75%.

  2. Porous Vycor membranes modified by chemical vapor deposition of boron nitride for gas separation

    SciTech Connect (OSTI)

    Levy, R.A.; Ravindranath, C.; Krasnoperov, L.N.; Opyrchal, J.; Ramos, E.S.

    1997-01-01

    This study focuses on the characterization of porous Vycor membranes modified by chemical vapor deposition of boron nitride (B-N-C-H) for gas separation. The B-N-C-H films were deposited on mesoporous Vycor tubes using triethylamine borane complex and ammonia as precursors. The effects of deposition temperature and reactant flow geometry on permselectivity of membranes with respect to various permeant gases were investigated. High selectivities (up to 50,000) were achieved between small molecules (He, H{sub 2}) and large molecules (N{sub 2}, Ar, C{sub 6}H{sub 5}CH{sub 3}). The measured activation energies for the He and H{sub 2} permeability are 9.5 kcal/mol and 12 kcal/mol, respectively. The membranes synthesized at lower temperatures and lower ammonia flow rates showed good mechanical and chemical stability.

  3. Dilute group III-V nitride intermediate band solar cells with contact blocking layers

    DOE Patents [OSTI]

    Walukiewicz, Wladyslaw; Yu, Kin Man

    2015-02-24

    An intermediate band solar cell (IBSC) is provided including a p-n junction based on dilute III-V nitride materials and a pair of contact blocking layers positioned on opposite surfaces of the p-n junction for electrically isolating the intermediate band of the p-n junction by blocking the charge transport in the intermediate band without affecting the electron and hole collection efficiency of the p-n junction, thereby increasing open circuit voltage (V.sub.OC) of the IBSC and increasing the photocurrent by utilizing the intermediate band to absorb photons with energy below the band gap of the absorber layers of the IBSC. Hence, the overall power conversion efficiency of a IBSC will be much higher than an conventional single junction solar cell. The p-n junction absorber layers of the IBSC may further have compositionally graded nitrogen concentrations to provide an electric field for more efficient charge collection.

  4. Dilute Group III-V nitride intermediate band solar cells with contact blocking layers

    DOE Patents [OSTI]

    Walukiewicz, Wladyslaw; Yu, Kin Man

    2012-07-31

    An intermediate band solar cell (IBSC) is provided including a p-n junction based on dilute III-V nitride materials and a pair of contact blocking layers positioned on opposite surfaces of the p-n junction for electrically isolating the intermediate band of the p-n junction by blocking the charge transport in the intermediate band without affecting the electron and hole collection efficiency of the p-n junction, thereby increasing open circuit voltage (V.sub.OC) of the IBSC and increasing the photocurrent by utilizing the intermediate band to absorb photons with energy below the band gap of the absorber layers of the IBSC. Hence, the overall power conversion efficiency of a IBSC will be much higher than an conventional single junction solar cell. The p-n junction absorber layers of the IBSC may further have compositionally graded nitrogen concentrations to provide an electric field for more efficient charge collection.

  5. Functionalization of cubic boron nitride films with rhodamine B and their fluorescent properties

    SciTech Connect (OSTI)

    Liu, W. M.; Zhang, H. Y.; Wang, P. F.; Ye, Q.; Yang, Y.; He, B.; Bello, I.; Lee, S. T.; Zhang, W. J.

    2011-08-08

    Fluorophore-functionalized cubic boron nitride (cBN) films grown by chemical vapor deposition were achieved by immobilizing rhodamine B isothiocyanate onto their surfaces. To perform the immobilization, the cBN substrates were modified with amino groups by photochemical reaction between hydrogen-terminated cBN surfaces and allylamine. The surface analysis of hydrogen-terminated cBN films surfaces and after functionalization with x-ray photoelectron spectroscopy verified that rhodamine B was indeed attached to the cBN surfaces with covalent bonding. The rhodamine B-functionalized cBN surfaces showed significant variation in fluorescent spectra and confocal imaging upon the treatment in acidic or basic solutions.

  6. Novel Electronic and Magnetic Properties of Graphene Nanoflakes in a Boron Nitride Layer

    SciTech Connect (OSTI)

    Zhou, Yungang; Wang, Zhiguo; Yang, Ping; Gao, Fei

    2012-04-05

    Novel electronic and magnetic properties of various-sized graphene nanoflakes (GNFs) embedded in a boron nitride (BN) layer are studied using ab initio methods. The feasibility of synthesizing hybrid GNF-BN structure, a desirable quantum dot structure, is explored. In this structure, photoexcited electrons and holes occupy the same spatial region - the GNF region - which offers an effective way to generate a GNF-based light-emitting device and adjust its emitted optical properties by controlling the size and array of GNF in the BN layer. Based on the important magnetism properties of embedded GNF, we propose a specific configuration to obtain a large spin. Together with the high stability of spin alignment, the proposed configuration can be exploited for spintronic devices.

  7. Thermal interface conductance across a graphene/hexagonal boron nitride heterojunction

    SciTech Connect (OSTI)

    Chen, Chun-Chung; Li, Zhen; Cronin, Stephen B. [Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089 (United States); Shi, Li [Department of Mechanical Engineering and Texas Materials Institute, University of Texas at Austin, Austin, Texas 78712 (United States)

    2014-02-24

    We measure thermal transport across a graphene/hexagonal boron nitride (h-BN) interface by electrically heating the graphene and measuring the temperature difference between the graphene and BN using Raman spectroscopy. Because the temperature of the graphene and BN are measured optically, this approach enables nanometer resolution in the cross-plane direction. A temperature drop of 60?K can be achieved across this junction at high electrical powers (14 mW). Based on the temperature difference and the applied power data, we determine the thermal interface conductance of this junction to be 7.4??10{sup 6}?Wm{sup ?2}K{sup ?1}, which is below the 10{sup 7}10{sup 8}?Wm{sup ?2}K{sup ?1} values previously reported for graphene/SiO{sub 2} interface.

  8. Graphene on boron-nitride: Moir pattern in the van der Waals energy

    SciTech Connect (OSTI)

    Neek-Amal, M. [Department of Physics, University of Antwerpen, Groenenborgerlaan 171, B-2020 Antwerpen (Belgium); Department of Physics, Shahid Rajaee University, Lavizan, Tehran 16788 (Iran, Islamic Republic of); Peeters, F. M. [Department of Physics, University of Antwerpen, Groenenborgerlaan 171, B-2020 Antwerpen (Belgium)

    2014-01-27

    The spatial dependence of the van der Waals (vdW) energy between graphene and hexagonal boron-nitride (h-BN) is investigated using atomistic simulations. The van der Waals energy between graphene and h-BN shows a hexagonal superlattice structure identical to the observed Moir pattern in the local density of states, which depends on the lattice mismatch and misorientation angle between graphene and h-BN. Our results provide atomistic features of the weak van der Waals interaction between graphene and BN which are in agreement with experiment and provide an analytical expression for the size of the spatial variation of the weak van der Waals interaction. We also found that the A-B-lattice symmetry of graphene is broken along the armchair direction.

  9. Polarization doping and the efficiency of III-nitride optoelectronic devices

    SciTech Connect (OSTI)

    Kivisaari, Pyry; Oksanen, Jani; Tulkki, Jukka

    2013-11-18

    The intrinsic polarization is generally considered a nuisance in III-nitride devices, but recent studies have shown that it can be used to enhance p- and n-type conductivity and even to replace impurity doping. We show by numerical simulations that polarization-doped light-emitting diode (LED) structures have a significant performance advantage over conventional impurity-doped LED structures. Our results indicate that polarization doping decreases electric fields inside the active region and potential barriers in the depletion region, as well as the magnitude of the quantum-confined Stark effect. The simulations also predict at least an order of magnitude increase in the current density corresponding to the maximum efficiency (i.e., smaller droop) as compared to impurity-doped structures. The obtained high doping concentrations could also enable, e.g., fabrication of III-N resonant tunneling diodes and improved ohmic contacts.

  10. The synthesis and structure of new transition metal lithium calcium nitride compounds

    SciTech Connect (OSTI)

    Hunting, Janet L.; Szymanski, Marta M.; Kowalsick, Amanda L.; Downie, Craig M.; DiSalvo, Francis J.

    2013-01-15

    Three new nitrides, Li{sub 3}Ca{sub 2}V{sub 0.79}Nb{sub 0.21}N{sub 4}, Li{sub 2}Ca{sub 2.67}Nb{sub 0.33}N{sub 3} and Li{sub 12}Ca{sub 9}W{sub 5}N{sub 20}, were synthesized in sealed niobium tubes using lithium nitride as a flux at temperatures ranging from 800 Degree-Sign C to 1050 Degree-Sign C. In all of these compounds, the transition metals are coordinated tetrahedrally by nitrogen; these tetrahedra are isolated from each other. Bullet Li{sub 3}Ca{sub 2}V{sub 0.79}Nb{sub 0.21}N{sub 4}, space group P2{sub 1}/m (no. 11), cell parameters a=5.7669(8) A, b=6.9123(9) A, c=6.0116(12) A, {beta}=90.727(9) Degree-Sign , Z=2, has a shared vanadium/niobium tetrahedral position which shares vertices with the tetrahedrally-coordinated lithium position. Bullet Li{sub 2}Ca{sub 2.67}Nb{sub 0.33}N{sub 3}, space group Req /o(3, Macron )m (no. 166), cell parameters a=3.6311(2) A, c=29.459(3) A, Z=3, contains a disordered tetrahedral calcium/niobium position, an octahedral calcium position and a triangularly coordinated lithium position. Bullet Li{sub 12}Ca{sub 9}W{sub 5}N{sub 20}, space group C2/c (no. 15), cell parameters a=27.7347(19) A, b=8.6652(6) A, c=10.7685(7) A, {beta}=110.314(2) Degree-Sign , Z=4, contains three crystallographically different tungsten positions as well as one disordered lithium position. - Graphical abstract: Crystal structure of Li{sub 3}Ca{sub 2}V{sub 0.79}Nb{sub 0.21}N{sub 4} depicting the chains of edge-sharing LiN{sub 4} (light hatching) and (V/Nb)N{sub 4} (dark hatching) tetrahedra viewed approximately along the [100] direction. Calcium atoms are shown as open circles and nitrogen atoms are colored black. Highlights: Black-Right-Pointing-Pointer Three new lithium calcium nitrides are synthesized. Black-Right-Pointing-Pointer Lithium nitride flux used in synthesis. Black-Right-Pointing-Pointer Structures contain isolated tetrahedrally coordinated transition metals. Black-Right-Pointing-Pointer Li{sub 12}Ca{sub 9}W{sub 5}N{sub 20} contains three crystallographically different W positions.

  11. Optical Strong Coupling between near-Infrared Metamaterials and Intersubband Transitions in III-Nitride Heterostructures

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

    Benz, Alexander; Campione, Salvatore; Moseley, Michael W.; Wierer, Jonathan J.; Allerman, Andrew A.; Wendt, Joel R.; Brener, Igal

    2014-08-25

    We present the design, realization, and characterization of optical strong light–matter coupling between intersubband transitions within a semiconductor heterostructures and planar metamaterials in the near-infrared spectral range. The strong light–matter coupling entity consists of a III-nitride intersubband superlattice heterostructure, providing a two-level system with a transition energy of ~0.8 eV (λ ~1.55 μm) and a planar “dogbone” metamaterial structure. Furthermore, as the bare metamaterial resonance frequency is varied across the intersubband resonance, a clear anticrossing behavior is observed in the frequency domain. We found that this strongly coupled entity could enable the realization of electrically tunable optical filters, a newmore » class of efficient nonlinear optical materials, or intersubband-based light-emitting diodes.« less

  12. Steel bonded dense silicon nitride compositions and method for their fabrication

    DOE Patents [OSTI]

    Landingham, Richard L. (Livermore, CA); Shell, Thomas E. (Tracy, CA)

    1987-01-01

    A two-stage bonding technique for bonding high density silicon nitride and other ceramic materials to stainless steel and other hard metals, and multilayered ceramic-metal composites prepared by the technique are disclosed. The technique involves initially slurry coating a surface of the ceramic material at about 1500.degree. C. in a vacuum with a refractory material and the stainless steel is then pressure bonded to the metallic coated surface by brazing it with nickel-copper-silver or nickel-copper-manganese alloys at a temperature in the range of about 850.degree. to 950.degree. C. in a vacuum. The two-stage bonding technique minimizes the temperature-expansion mismatch between the dissimilar materials.

  13. Local residual stress monitoring of aluminum nitride MEMS using UV micro-Raman spectroscopy

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

    Choi, Sukwon; Griffin, Benjamin A.

    2016-01-06

    Localized stress variation in aluminum nitride (AlN) sputtered on patterned metallization has been monitored through the use of UV micro-Raman spectroscopy. This technique utilizing 325 nm laser excitation allows detection of the AlN E2(high) phonon mode in the presence of metal electrodes beneath the AlN layer with a high spatial resolution of less than 400 nm. The AlN film stress shifted 400 MPa from regions where AlN was deposited over a bottom metal electrode versus silicon dioxide. Thus, across wafer stress variations were also investigated showing that wafer level stress metrology, for example using wafer curvature measurements, introduces large uncertaintiesmore » for predicting the impact of AlN residual stress on the device performance.« less

  14. Contact-induced spin polarization of monolayer hexagonal boron nitride on Ni(111)

    SciTech Connect (OSTI)

    Ohtomo, Manabu; Entani, Shiro; Matsumoto, Yoshihiro; Naramoto, Hiroshi; Sakai, Seiji; Yamauchi, Yasushi; Kuzubov, Alex A.; Eliseeva, Natalya S.; Avramov, Pavel V.

    2014-02-03

    Hexagonal boron nitride (h-BN) is a promising barrier material for graphene spintronics. In this Letter, spin-polarized metastable de-excitation spectroscopy (SPMDS) is employed to study the spin-dependent electronic structure of monolayer h-BN/Ni(111). The extreme surface sensitivity of SPMDS enables us to elucidate a partial filling of the in-gap states of h-BN without any superposition of Ni 3d signals. The in-gap states are shown to have a considerable spin polarization parallel to the majority spin of Ni. The positive spin polarization is attributed to the π-d hybridization and the effective spin transfer to the nitrogen atoms at the h-BN/Ni(111) interface.

  15. Vacancies in fully hydrogenated boron nitride layer: implications for functional nanodevices

    SciTech Connect (OSTI)

    Zhou, Yungang; Wang, Zhiguo; Nie, JL; Yang, Ping; Sun, Xin; Khaleel, Mohammad A.; Zu, Xiaotao; Gao, Fei

    2012-03-01

    Using density functional theory, a series of calculations of structural and electronic properties of hydrogen vacancies in a fully hydrogenated boron nitride (fH-BN) layer were conducted. By dehydrogenating the fH-BN structure, B-terminated vacancies can be created which induce complete spin polarization around the Fermi level, irrespective of the vacancy size. On the contrary, the fH-BN structure with N-terminated vacancies can be a small-gap semiconductor, a typical spin gapless semiconductor, or a metal depending on the vacancy size. Utilizing such vacancy-induced band gap and magnetism changes, possible applications in spintronics are proposed, and a special fH-BN based quantum dot device is designed.

  16. Spintronics with graphene-hexagonal boron nitride van der Waals heterostructures

    SciTech Connect (OSTI)

    Kamalakar, M. Venkata Dankert, André; Bergsten, Johan; Ive, Tommy; Dash, Saroj P.

    2014-11-24

    Hexagonal boron nitride (h-BN) is a large bandgap insulating isomorph of graphene, ideal for atomically thin tunnel barrier applications. In this letter, we demonstrate large area chemical vapor deposited (CVD) h-BN as a promising spin tunnel barrier in graphene spin transport devices. In such structures, the ferromagnetic tunnel contacts with h-BN barrier are found to show robust tunneling characteristics over a large scale with resistances in the favorable range for efficient spin injection into graphene. The non-local spin transport and precession experiments reveal spin lifetime ≈500 ps and spin diffusion length ≈1.6 μm in graphene with tunnel spin polarization ≈11% at 100 K. The electrical and spin transport measurements at different injection bias current and gate voltages confirm tunnel spin injection through h-BN barrier. These results open up possibilities for implementation of large area CVD h-BN in spintronic technologies.

  17. Silicon nitride swirl lower-chamber for high power turbocharged diesel engines

    SciTech Connect (OSTI)

    Kamiya, S.; Murachi, M.; Kawamoto, H.; Kato, S.; Kawakami, S.; Suzuki, Y.

    1985-01-01

    This paper describes application of sintered silicon nitride to the swirl lower-chamber in order to improve performance of turbocharged diesel engines. Various stress analyses by finite element method and stress measurements have been applied to determine the design specifications for the component, which compromise brittleness of ceramic materials. Material development was conducted to evaluate strength, fracture toughness, and thermal properties for the sintered bodies. Ceramic injection molding has been employed to fabricate components with large quantities. In the present work. Quality assurance for the components can be made by reliability evaluation methods as well as non-destructive and stress loading inspections. It is found that the engine performance with ceramic component has been increased in the power out put of 9ps as compared to that of conventional engines.

  18. Pt monolayer shell on nitrided alloy core — A path to highly stable oxygen reduction catalyst

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

    Hu, Jue; Kuttiyiel, Kurian A.; Sasaki, Kotaro; Su, Dong; Yang, Tae -Hyun; Park, Gu -Gon; Zhang, Chengxu; Chen, Guangyu; Adzic, Radoslav R.

    2015-07-22

    The inadequate activity and stability of Pt as a cathode catalyst under the severe operation conditions are the critical problems facing the application of the proton exchange membrane fuel cell (PEMFC). Here we report on a novel route to synthesize highly active and stable oxygen reduction catalysts by depositing Pt monolayer on a nitrided alloy core. The prepared PtMLPdNiN/C catalyst retains 89% of the initial electrochemical surface area after 50,000 cycles between potentials 0.6 and 1.0 V. By correlating electron energy-loss spectroscopy and X-ray absorption spectroscopy analyses with electrochemical measurements, we found that the significant improvement of stability of themore » PtMLPdNiN/C catalyst is caused by nitrogen doping while reducing the total precious metal loading.« less

  19. Pt monolayer shell on nitrided alloy core A path to highly stable oxygen reduction catalyst

    SciTech Connect (OSTI)

    Hu, Jue; Kuttiyiel, Kurian A.; Sasaki, Kotaro; Su, Dong; Yang, Tae -Hyun; Park, Gu -Gon; Zhang, Chengxu; Chen, Guangyu; Adzic, Radoslav R.

    2015-07-22

    The inadequate activity and stability of Pt as a cathode catalyst under the severe operation conditions are the critical problems facing the application of the proton exchange membrane fuel cell (PEMFC). Here we report on a novel route to synthesize highly active and stable oxygen reduction catalysts by depositing Pt monolayer on a nitrided alloy core. The prepared PtMLPdNiN/C catalyst retains 89% of the initial electrochemical surface area after 50,000 cycles between potentials 0.6 and 1.0 V. By correlating electron energy-loss spectroscopy and X-ray absorption spectroscopy analyses with electrochemical measurements, we found that the significant improvement of stability of the PtMLPdNiN/C catalyst is caused by nitrogen doping while reducing the total precious metal loading.

  20. Transient fission-gas behavior in uranium nitride fuel under proposed space applications. Doctoral thesis

    SciTech Connect (OSTI)

    Deforest, D.L.

    1991-12-01

    In order to investigate whether fission gas swelling and release would be significant factors in a space based nuclear reactor operating under the Strategic Defense Initiative (SDI) program, the finite element program REDSTONE (Routine For Evaluating Dynamic Swelling in Transient Operational Nuclear Environments) was developed to model the 1-D, spherical geometry diffusion equations describing transient fission gas behavior in a single uranium nitride fuel grain. The equations characterized individual bubbles, rather than bubble groupings. This limits calculations to those scenarios where low temperatures, low burnups, or both were present. Instabilities in the bubble radii calculations forced the implementation of additional constraints limiting the bubble sizes to minimum and maximum (equilibrium) radii. The validity of REDSTONE calculations were checked against analytical solutions for internal consistency and against experimental studies for agreement with swelling and release results.

  1. The cost of silicon nitride powder: What must it be to compete?

    SciTech Connect (OSTI)

    Das, S.; Curlee, T.R.

    1992-02-01

    The ability of advanced ceramic components to compete with similar metallic parts will depend in part on current and future efforts to reduce the cost of ceramic parts. This paper examines the potential reductions in part cost that could result from the development of less expensive advanced ceramic powders. The analysis focuses specifically on two silicon nitride engine components -- roller followers and turbocharger rotors. The results of the process-cost models developed for this work suggest that reductions in the cost of advanced silicon nitride powder from its current level of about $20 per pound to about $5 per pound will not in itself be sufficient to lower the cost of ceramic parts below the current cost of similar metallic components. This work also examines if combinations of lower-cost powders and further improvements in other key technical parameters to which costs are most sensitive could push the cost of ceramics below the cost of metallics. Although these sensitivity analyses are reflective of technical improvements that are very optimistic, the resulting part costs are estimated to remain higher than similar metallic parts. Our findings call into question the widely-held notion that the cost of ceramic components must not exceed the cost of similar metallic parts if ceramics are to be competitive. Economic viability will ultimately be decided not on the basis of which part is less costly, but on an assessment of the marginal costs and benefits provided by ceramics and metallics. This analysis does not consider the benefits side of the equation. Our findings on the cost side of the equation suggest that the competitiveness of advanced ceramics will ultimately be decided by our ability to evaluate and communicate the higher benefits that advanced ceramic parts may offer.

  2. The cost of silicon nitride powder: What must it be to compete

    SciTech Connect (OSTI)

    Das, S.; Curlee, T.R.

    1992-02-01

    The ability of advanced ceramic components to compete with similar metallic parts will depend in part on current and future efforts to reduce the cost of ceramic parts. This paper examines the potential reductions in part cost that could result from the development of less expensive advanced ceramic powders. The analysis focuses specifically on two silicon nitride engine components -- roller followers and turbocharger rotors. The results of the process-cost models developed for this work suggest that reductions in the cost of advanced silicon nitride powder from its current level of about $20 per pound to about $5 per pound will not in itself be sufficient to lower the cost of ceramic parts below the current cost of similar metallic components. This work also examines if combinations of lower-cost powders and further improvements in other key technical parameters to which costs are most sensitive could push the cost of ceramics below the cost of metallics. Although these sensitivity analyses are reflective of technical improvements that are very optimistic, the resulting part costs are estimated to remain higher than similar metallic parts. Our findings call into question the widely-held notion that the cost of ceramic components must not exceed the cost of similar metallic parts if ceramics are to be competitive. Economic viability will ultimately be decided not on the basis of which part is less costly, but on an assessment of the marginal costs and benefits provided by ceramics and metallics. This analysis does not consider the benefits side of the equation. Our findings on the cost side of the equation suggest that the competitiveness of advanced ceramics will ultimately be decided by our ability to evaluate and communicate the higher benefits that advanced ceramic parts may offer.

  3. Low-temperature CVD of iron, cobalt, and nickel nitride thin films from bis[di(tert-butyl)amido]metal(II) precursors and ammonia

    SciTech Connect (OSTI)

    Cloud, Andrew N.; Abelson, John R., E-mail: abelson@illinois.edu [Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, 201 Materials Science and Engineering Building, 1304 W. Green St., Urbana, Illinois 61801 (United States); Davis, Luke M.; Girolami, Gregory S., E-mail: girolami@scs.illinois.edu [School of Chemical Sciences, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, Illinois 61801 (United States)

    2014-03-15

    Thin films of late transition metal nitrides (where the metal is iron, cobalt, or nickel) are grown by low-pressure metalorganic chemical vapor deposition from bis[di(tert-butyl)amido]metal(II) precursors and ammonia. These metal nitrides are known to have useful mechanical and magnetic properties, but there are few thin film growth techniques to produce them based on a single precursor family. The authors report the deposition of metal nitride thin films below 300?C from three recently synthesized M[N(t-Bu){sub 2}]{sub 2} precursors, where M?=?Fe, Co, and Ni, with growth onset as low as room temperature. Metal-rich phases are obtained with constant nitrogen content from growth onset to 200?C over a range of feedstock partial pressures. Carbon contamination in the films is minimal for iron and cobalt nitride, but similar to the nitrogen concentration for nickel nitride. X-ray photoelectron spectroscopy indicates that the incorporated nitrogen is present as metal nitride, even for films grown at the reaction onset temperature. Deposition rates of up to 18?nm/min are observed. The film morphologies, growth rates, and compositions are consistent with a gas-phase transamination reaction that produces precursor species with high sticking coefficients and low surface mobilities.

  4. Pre-Oxidized and Nitrided Stainless Steel Foil for Proton Exchange Membrane Fuel Cell Bipolar Plates: Part 1 Corrosion, Interfacial Contact Resistance, and Surface Structure

    SciTech Connect (OSTI)

    Brady, Michael P; Wang, Heli; Turner, John; Meyer III, Harry M; More, Karren Leslie; Tortorelli, Peter F; McCarthy, Brian D

    2010-01-01

    Thermal (gas) nitridation of stainless steels can yield low interfacial contact resistance (ICR), electrically-conductive and corrosion-resistant nitride containing surfaces (Cr2N, CrN, TiN, V2N, VN, etc) of interest for fuel cells, batteries, and sensors. This paper presents the results of scale up studies to determine the feasibility of extending the nitridation approach to thin 0.1 mm stainless steel alloy foils for proton exchange membrane fuel cell (PEMFC) bipolar plates. A major emphasis was placed on selection of alloy foil composition and nitidation conditions potentially capable of meeting the stringent cost goals for automotive PEMFC applications. Developmental Fe-20Cr-4V alloy and type 2205 stainless steel foils were treated by pre-oxidation and nitridation to form low-ICR, corrosion-resistant surfaces. Promising behavior was observed under simulated aggressive anode- and cathode- side bipolar plate conditions for both materials. Variation in ICR values were observed for treated 2205 foil, with lower (better) values generally observed for the treated Fe-20Cr-4V. This behavior was linked to the nature of the pre-oxidized and nitrided surface structure, which contained through surface layer thickness V-nitride particles in the case of Fe-20Cr-4V but near continuous chromia in the case of 2205 stainless steel. The implications of these findings for stamped bipolar plate foils are discussed.

  5. Tuned critical avalanche scaling in bulk metallic glasses

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

    Antonaglia, James; Xie, Xie; Schwarz, Gregory; Wraith, Matthew; Qiao, Junwei; Zhang, Yong; Liaw, Peter K.; Uhl, Jonathan T.; Dahmen, Karin A.

    2014-03-17

    In this study, ingots of the bulk metallic glass (BMG), Zr64.13Cu15.75Ni10.12Al10 in atomic percent (at. %), are compressed at slow strain rates. The deformation behavior is characterized by discrete, jerky stress-drop bursts (serrations). Here we present a quantitative theory for the serration behavior of BMGs, which is a critical issue for the understanding of the deformation characteristics of BMGs. The mean-field interaction model predicts the scaling behavior of the distribution, D(S), of avalanche sizes, S, in the experiments. D(S) follows a power law multiplied by an exponentially-decaying scaling function. The size of the largest observed avalanche depends on experimental tuning-parameters,more » such as either imposed strain rate or stress. Similar to crystalline materials, the plasticity of BMGs reflects tuned criticality showing remarkable quantitative agreement with the slip statistics of slowly-compressed nanocrystals. The results imply that material-evaluation methods based on slip statistics apply to both crystalline and BMG materials.« less

  6. International Round-Robin Testing of Bulk Thermoelectrics

    SciTech Connect (OSTI)

    Wang, Hsin; Porter, Wallace D; Bottner, Harold; Konig, Jan; Chen, Lidong; Bai, Shengqiang; Tritt, Terry M.; Mayolett, Alex; Smith, Charlene; Harris, Fred; Sharp, Jeff; Lo, Jason; Keinke, Holger; Kiss, Laszlo I.

    2011-11-01

    Two international round-robin studies were conducted on transport properties measurements of bulk thermoelectric materials. The study discovered current measurement problems. In order to get ZT of a material four separate transport measurements must be taken. The round-robin study showed that among the four properties Seebeck coefficient is the one can be measured consistently. Electrical resistivity has +4-9% scatter. Thermal diffusivity has similar +5-10% scatter. The reliability of the above three properties can be improved by standardizing test procedures and enforcing system calibrations. The worst problem was found in specific heat measurements using DSC. The probability of making measurement error is great due to the fact three separate runs must be taken to determine Cp and the baseline shift is always an issue for commercial DSC. It is suggest the Dulong Petit limit be always used as a guide line for Cp. Procedures have been developed to eliminate operator and system errors. The IEA-AMT annex is developing standard procedures for transport properties testing.

  7. Magnetic and magnetocaloric properties of bulk dysprosium chromite

    SciTech Connect (OSTI)

    McDannald, A.; Institute of Material Science, University of Connecticut, Storrs, Connecticut 06269 ; Kuna, L.; Jain, M.; Department of Physics, University of Connecticut, Storrs, Connecticut 06269

    2013-09-21

    In this work, a polycrystalline bulk DyCrO{sub 3} sample was prepared by a solution route and the structural and magnetic properties were investigated. The phase purity and ionic valence state of the DyCrO{sub 3} sample were determined by x-ray diffraction/Raman spectroscopy and x-ray photoelectron spectroscopy, respectively. The AC and DC magnetization measurements revealed the onset of antiferromagnetic order at 146 K with an effective moment of 8.88 μ{sub B}. Isothermal magnetization measurements of this material are presented for the first time, showing a peak in the coercive field at 80 K that is explained by the competition between the paramagnetic Dy{sup 3+} and Cr{sup 3+} sublattices. DyCrO{sub 3} was found to display a large magnetocaloric effect (8.4 J/kg K) and relative cooling power (217 J/kg) at 4 T applied field, which renders DyCrO{sub 3} useful for magnetic refrigeration between 5 K and 30 K.

  8. A new class of high ZT doped bulk nanothermoelectrics through bottom-up

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

    synthesis | Department of Energy new class of high ZT doped bulk nanothermoelectrics through bottom-up synthesis A new class of high ZT doped bulk nanothermoelectrics through bottom-up synthesis Reports on synthesis of large quantities of p- and n-type nanocrystals then sintered into bulk samples with high power factors and low thermal conductivity through impurity doping and nanostructuring PDF icon ramanath.pdf More Documents & Publications Nano-structures Thermoelectric Materals -

  9. Bulk Fuel Procurement Process & Alternative Drop-in Fuel | Department of

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

    Energy Bulk Fuel Procurement Process & Alternative Drop-in Fuel Bulk Fuel Procurement Process & Alternative Drop-in Fuel Jeanne Binder, DLA Energy, presentation on Bulk Fuel Procurement Process & Alternative Drop-in Fuel at the Advanced Biofuels Industry Roundtable. PDF icon 7_binder_roundtable.pdf More Documents & Publications DLA Energy: Your Supplemental Energy Contracting Venue Advanced Drop-In Biofuels Initiative Agenda FUPWG Spring 2015 Agenda and Presentations

  10. Unpaired Majorana modes in Josephson-Junction Arrays with gapless bulk excitations

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

    Pino, M.; Tsvelik, A.; Ioffe, L. B.

    2015-11-06

    In this study, the search for Majorana bound states in solid-state physics has been limited to materials that display a gap in their bulk spectrum. We show that such unpaired states appear in certain quasi-one-dimensional Josephson-junction arrays with gapless bulk excitations. The bulk modes mediate a coupling between Majorana bound states via the Ruderman-Kittel-Yosida-Kasuya mechanism. As a consequence, the lowest energy doublet acquires a finite energy difference. For a realistic set of parameters this energy splitting remains much smaller than the energy of the bulk eigenstates even for short chains of length L~10.

  11. The Role of Surface Chemistry and Bulk Properties on the Cycling...

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

    The Role of Surface Chemistry and Bulk Properties on the Cycling and Rate Capability of Lithium Positive Electrode Materials The Role of Surface Chemistry on the Cycling and ...

  12. Raman vibrational spectra of bulk to monolayer Re S 2 with lower...

    Office of Scientific and Technical Information (OSTI)

    Title: Raman vibrational spectra of bulk to monolayer Re S 2 with lower symmetry Authors: Feng, Yanqing ; Zhou, Wei ; Wang, Yaojia ; Zhou, Jian ; Liu, Erfu ; Fu, Yajun ; Ni, ...

  13. The impact of gas bulk rotation on the Ly? line

    SciTech Connect (OSTI)

    Garavito-Camargo, Juan N.; Forero-Romero, Jaime E.; Dijkstra, Mark E-mail: je.forero@uniandes.edu.co

    2014-11-10

    We present results of radiative transfer calculations to measure the impact of gas bulk rotation on the morphology of the Ly? emission line in distant galaxies. We model a galaxy as a sphere with an homogeneous mixture of dust and hydrogen at a constant temperature. These spheres undergo solid-body rotation with maximum velocities in the range 0-300 km s{sup 1} and neutral hydrogen optical depths in the range ?{sub H} = 10{sup 5}-10{sup 7}. We consider two types of source distributions in the sphere: central and homogeneous. Our main result is that rotation introduces a dependence of the line morphology with viewing angle and rotational velocity. Observations with a line of sight parallel to the rotation axis yield line morphologies similar to the static case. For lines of sight perpendicular to the rotation axis, both the intensity at the line center and the line width increase with rotational velocity. Along the same line of sight, the line becomes single peaked at rotational velocities close to half the line width in the static case. Notably, we find that rotation does not induce any spatial anisotropy in the integrated line flux, the escape fraction or the average number of scatterings. This is because Lyman scattering through a rotating solid-body proceeds identically to the static case. The only difference is the Doppler shift from the different regions in the sphere that move with respect to the observer. This allows us to derive an analytic approximation for the viewing-angle dependence of the emerging spectrum, as a function of rotational velocity.

  14. Novel Approaches to High-Efficiency III-V Nitride Heterostructure Emitters for Next-Generation Lighting Applications

    SciTech Connect (OSTI)

    Russell D. Dupuis

    2004-09-30

    We report research activities and technical progress on the development of high-efficiency long wavelength ({lambda} {approx} 540nm) green light emitting diodes which covers the first year of the three-year program ''Novel approaches to high-efficiency III-V nitride heterostructure emitters for next-generation lighting applications''. The first year activities were focused on the installation, set-up, and use of advanced equipment for the metalorganic chemical vapor deposition growth of III-nitride films and the characterization of these materials (Task 1) and the design, fabrication, testing of nitride LEDs (Task 4). As a progress highlight, we obtained improved quality of {approx} 2 {micro}m-thick GaN layers (as measured by the full width at half maximum of the asymmetric (102) X-ray diffraction peak of less than 350 arc-s) and higher p-GaN:Mg doping level (free hole carrier higher than 1E18 cm{sup -3}). Also in this year, we have developed the growth of InGaN/GaN active layers for long-wavelength green light emitting diodes, specifically, for emission at {lambda} {approx} 540nm. The effect of the Column III precursor (for Ga) and the post-growth thermal annealing effect were also studied. Our LED device fabrication process was developed and initially optimized, especially for low-resistance ohmic contacts for p-GaN:Mg layers, and blue-green light emitting diode structures were processed and characterized.

  15. Process for producing high purity silicon nitride by the direct reaction between elemental silicon and nitrogen-hydrogen liquid reactants

    DOE Patents [OSTI]

    Pugar, E.A.; Morgan, P.E.D.

    1987-09-15

    A process is disclosed for producing, at a low temperature, a high purity reaction product consisting essentially of silicon, nitrogen, and hydrogen which can then be heated to produce a high purity alpha silicon nitride. The process comprises: reacting together a particulate elemental high purity silicon with a high purity nitrogen-hydrogen reactant in its liquid state (such as ammonia or hydrazine) having the formula: N/sub n/H/sub (n+m)/ wherein: n = 1--4 and m = 2 when the nitrogen-hydrogen reactant is straight chain, and 0 when the nitrogen-hydrogen reactant is cyclic. High purity silicon nitride can be formed from this intermediate product by heating the intermediate product at a temperature of from about 1200--1700/degree/C for a period from about 15 minutes up to about 2 hours to form a high purity alpha silicon nitride product. The discovery of the existence of a soluble Si/endash/N/endash/H intermediate enables chemical pathways to be explored previously unavailable in conventional solid-state approaches to silicon-nitrogen ceramics

  16. Process for producing high purity silicon nitride by the direct reaction between elemental silicon and nitrogen-hydrogen liquid reactants

    DOE Patents [OSTI]

    Pugar, Eloise A.; Morgan, Peter E. D.

    1990-01-01

    A process is disclosed for producing, at a low temperature, a high purity reaction product consisting essentially of silicon, nitrogen, and hydrogen which can then be heated to produce a high purity alpha silicon nitride. The process comprises: reacting together a particulate elemental high purity silicon with a high purity nitrogen-hydrogen reactant in its liquid state (such as ammonia or hydrazine) having the formula: N.sub.n H.sub.(n+m) wherein: n=1-4 and m=2 when the nitrogen-hydrogen reactant is straight chain, and 0 when the nitrogen-hydrogen reactant is cyclic. High purity silicon nitride can be formed from this intermediate product by heating the intermediate product at a temperature of from about 1200.degree.-1700.degree. C. for a period from about 15 minutes up to about 2 hours to form a high purity alpha silicon nitride product. The discovery of the existence of a soluble Si-N-H intermediate enables chemical pathways to be explored previously unavailable in conventional solid state approaches to silicon-nitrogen ceramics.

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

    SciTech Connect (OSTI)

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

    2014-01-20

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

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

    SciTech Connect (OSTI)

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

    2014-12-28

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

  19. Bulk Nanostructured FCC Steels With Enhanced Radiation Tolerance

    SciTech Connect (OSTI)

    Zhang, Xinghang; Hartwig, K. Ted; Allen, Todd; Yang, Yong

    2012-10-27

    The objective of this project is to increase radiation tolerance in austenitic steels through optimization of grain size and grain boundary (GB) characteristics. The focus will be on nanocrystalline austenitic Fe-Cr-Ni alloys with an fcc crystal structure. The long-term goal is to design and develop bulk nanostructured austenitic steels with enhanced void swelling resistance and substantial ductility, and to enhance their creep resistance at elevated temperatures via GB engineering. The combination of grain refinement and grain boundary engineering approaches allows us to tailor the material strength, ductility, and resistance to swelling by 1) changing the sink strength for point defects, 2) by increasing the nucleation barriers for bubble formation at GBs, and 3) by changing the precipitate distributions at boundaries. Compared to ferritic/martensitic steels, austenitic stainless steels (SS) possess good creep and fatigue resistance at elevated temperatures, and better toughness at low temperature. However, a major disadvantage of austenitic SS is that they are vulnerable to significant void swelling in nuclear reactors, especially at the temperatures and doses anticipated in the Advanced Burner Reactor. The lack of resistance to void swelling in austenitic alloys led to the switch to ferritic/martensitic steels as the preferred material for the fast reactor cladding application. Recently a type of austenitic stainless steel, HT-UPS, was developed at ORNL, and is expected to show enhanced void swelling resistance through the trapping of point defects at nanometersized carbides. Reducing the grain size and increasing the fraction of low energy grain boundaries should reduce the available radiation-produced point defects (due to the increased sink area of the grain boundaries), should make bubble nucleation at the boundaries less likely (by reducing the fraction of high-energy boundaries), and improve the strength and ductility under radiation by producing a higher density of nanometer sized carbides on the boundaries. This project will focus on void swelling but advances in processing of austenitic steels are likely to also improve the radiation response of the mechanical properties.

  20. Bulk and surface controlled diffusion of fission gas atoms

    SciTech Connect (OSTI)

    Andersson, Anders D.

    2012-08-09

    Fission gas retention and release impact nuclear fuel performance by, e.g., causing fuel swelling leading to mechanical interaction with the clad, increasing the plenum pressure and reducing the gap thermal conductivity. All of these processes are important to understand in order to optimize operating conditions of nuclear reactors and to simulate accident scenarios. Most fission gases have low solubility in the fuel matrix, which is especially pronounced for large fission gas atoms such as Xe and Kr, and as a result there is a significant driving force for segregation of gas atoms to extended defects such as grain boundaries or dislocations and subsequently for nucleation of gas bubbles at these sinks. Several empirical or semi-empirical models have been developed for fission gas release in nuclear fuels, e.g. [1-6]. One of the most commonly used models in fuel performance codes was published by Massih and Forsberg [3,4,6]. This model is similar to the early Booth model [1] in that it applies an equivalent sphere to separate bulk UO{sub 2} from grain boundaries represented by the sphere circumference. Compared to the Booth model, it also captures trapping at grain boundaries, fission gas resolution and it describes release from the boundary by applying timedependent boundary conditions to the circumference. In this work we focus on the step where fission gas atoms diffuse from the grain interior to the grain boundaries. The original Massih-Forsberg model describes this process by applying an effective diffusivity divided into three temperature regimes. In this report we present results from density functional theory calculations (DFT) that are relevant for the high (D{sub 3}) and intermediate (D{sub 2}) temperature diffusivities of fission gases. The results are validated by making a quantitative comparison to Turnbull's [8-10] and Matzke's data [12]. For the intrinsic or high temperature regime we report activation energies for both Xe and Kr diffusion in UO{sub 2{+-}x}, which compare favorably to available experiments. This is an extension of previous work [13]. In particular, it applies improved chemistry models for the UO{sub 2{+-}x} nonstoichiometry and its impact on the fission gas activation energies. The derivation of these models follows the approach that used in our recent study of uranium vacancy diffusion in UO{sub 2} [14]. Also, based on the calculated DFT data we analyze vacancy enhanced diffusion mechanisms in the intermediate temperature regime. In addition to vacancy enhanced diffusion we investigate species transport on the (111) UO{sub 2} surface. This is motivated by the formation of small voids partially filled with fission gas atoms (bubbles) in UO{sub 2} under irradiation, for which surface diffusion could be the rate-limiting transport step. Diffusion of such bubbles constitutes an alternative mechanism for mass transport in these materials.

  1. Methods for and products of processing nanostructure nitride, carbonitride and oxycarbonitride electrode power materials by utilizing sol gel technology for supercapacitor applications

    DOE Patents [OSTI]

    Huang, Yuhong (West Hills, CA); Wei, Oiang (West Hills, CA); Chu, Chung-tse (Chatsworth, CA); Zheng, Haixing (Oak Park, CA)

    2001-01-01

    Metal nitride, carbonitride, and oxycarbonitride powder with high surface area (up to 150 m.sup.2 /g) is prepared by using sol-gel process. The metal organic precursor, alkoxides or amides, is synthesized firstly. The metal organic precursor is modified by using unhydrolyzable organic ligands or templates. A wet gel is formed then by hydrolysis and condensation process. The solvent in the wet gel is then be removed supercritically to form porous amorphous hydroxide. This porous hydroxide materials is sintered to 725.degree. C. under the ammonia flow and porous nitride powder is formed. The other way to obtain high surface area nitride, carbonitride, and oxycarbonitride powder is to pyrolyze polymerized templated metal amides aerogel in an inert atmosphere. The electrochemical capacitors are prepared by using sol-gel prepared nitride, carbonitride, and oxycarbonitride powder. Two methods are used to assemble the capacitors. Electrode is formed either by pressing the mixture of nitride powder and binder to a foil, or by depositing electrode coating onto metal current collector. The binder or coating is converted into a continuous network of electrode material after thermal treatment to provide enhanced energy and power density. Liquid electrolyte is soaked into porous electrode. The electrochemical capacitor assembly further has a porous separator layer between two electrodes/electrolyte and forming a unit cell.

  2. Antifuse with a single silicon-rich silicon nitride insulating layer

    DOE Patents [OSTI]

    Habermehl, Scott D.; Apodaca, Roger T.

    2013-01-22

    An antifuse is disclosed which has an electrically-insulating region sandwiched between two electrodes. The electrically-insulating region has a single layer of a non-hydrogenated silicon-rich (i.e. non-stoichiometric) silicon nitride SiN.sub.X with a nitrogen content X which is generally in the range of 0

  3. Preparation and properties of hexagonal boron nitride fibers used as high temperature membrane filter

    SciTech Connect (OSTI)

    Hou, Xinmei Yu, Ziyou; Li, Yang; Chou, Kuo-Chih

    2014-01-01

    Graphical abstract: - Highlights: • h-BN fibers were successfully fabricated using H{sub 3}BO{sub 3} and C{sub 3}H{sub 6}N{sub 6} as raw materials. • The obtained BN fibers were polycrystalline and uniform in morphology. • It exhibited good oxidation resistance and low thermal expansion coefficient. - Abstract: Hexagonal boron nitride fibers were synthesized via polymeric precursor method using boric acid (H{sub 3}BO{sub 3}) and melamine (C{sub 3}H{sub 6}N{sub 6}) as raw materials. The precursor fibers were synthesized by water bath and BN fibers were prepared from the precursor at 1873 K for 3 h in flowing nitrogen atmosphere. The crystalline phase and microstructures of BN fibers were examined by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy and high resolution electron microscopy. The results showed that h-BN fibers with uniform morphology were successfully fabricated. The well-synthesized BN fibers were polycrystalline with 0.4–1.5 μm in diameter and 200–500 μm in length. The as-prepared samples exhibited good oxidation resistance and low thermal expansion coefficient at high temperature.

  4. Interlayer coupling enhancement in graphene/hexagonal boron nitride heterostructures by intercalated defects or vacancies

    SciTech Connect (OSTI)

    Park, Sohee [Department of Materials Science and Engineering, Seoul National University, Seoul 151-747 (Korea, Republic of)] [Department of Materials Science and Engineering, Seoul National University, Seoul 151-747 (Korea, Republic of); Park, Changwon [Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)] [Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Kim, Gunn, E-mail: gunnkim@sejong.ac.kr [Department of Physics and Graphene Research Institute, Sejong University, Seoul 143-747 (Korea, Republic of)] [Department of Physics and Graphene Research Institute, Sejong University, Seoul 143-747 (Korea, Republic of)

    2014-04-07

    Hexagonal boron nitride (hBN), a remarkable material with a two-dimensional atomic crystal structure, has the potential to fabricate heterostructures with unusual properties. We perform first-principles calculations to determine whether intercalated metal atoms and vacancies can mediate interfacial coupling and influence the structural and electronic properties of the graphene/hBN heterostructure. Metal impurity atoms (Li, K, Cr, Mn, Co, and Cu), acting as extrinsic defects between the graphene and hBN sheets, produce n-doped graphene. We also consider intrinsic vacancy defects and find that a boron monovacancy in hBN acts as a magnetic dopant for graphene, whereas a nitrogen monovacancy in hBN serves as a nonmagnetic dopant for graphene. In contrast, the smallest triangular vacancy defects in hBN are unlikely to result in significant changes in the electronic transport of graphene. Our findings reveal that a hBN layer with some vacancies or metal impurities enhances the interlayer coupling in the graphene/hBN heterostructure with respect to charge doping and electron scattering.

  5. Resistive switching phenomena of tungsten nitride thin films with excellent CMOS compatibility

    SciTech Connect (OSTI)

    Hong, Seok Man; Kim, Hee-Dong; An, Ho-Myoung; Kim, Tae Geun

    2013-12-15

    Graphical abstract: - Highlights: The resistive switching characteristics of WN{sub x} thin films. Excellent CMOS compatibility WN{sub x} films as a resistive switching material. Resistive switching mechanism revealed trap-controlled space charge limited conduction. Good endurance and retention properties over 10{sup 5} cycles, and 10{sup 5} s, respectively - Abstract: We report the resistive switching (RS) characteristics of tungsten nitride (WN{sub x}) thin films with excellent complementary metal-oxide-semiconductor (CMOS) compatibility. A Ti/WN{sub x}/Pt memory cell clearly shows bipolar RS behaviors at a low voltage of approximately 2.2 V. The dominant conduction mechanisms at low and high resistance states were verified by Ohmic behavior and trap-controlled space-charge-limited conduction, respectively. A conducting filament model by a redox reaction explains the RS behavior in WN{sub x} films. We also demonstrate the memory characteristics during pulse operation, including a high endurance over >10{sup 5} cycles and a long retention time of >10{sup 5} s.

  6. Carbide/nitride grain refined rare earth-iron-boron permanent magnet and method of making

    DOE Patents [OSTI]

    McCallum, R.W.; Branagan, D.J.

    1996-01-23

    A method of making a permanent magnet is disclosed wherein (1) a melt is formed having a base alloy composition comprising RE, Fe and/or Co, and B (where RE is one or more rare earth elements) and (2) TR (where TR is a transition metal selected from at least one of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, and Al) and at least one of C and N are provided in the base alloy composition melt in substantially stoichiometric amounts to form a thermodynamically stable compound (e.g. TR carbide, nitride or carbonitride). The melt is rapidly solidified in a manner to form particulates having a substantially amorphous (metallic glass) structure and a dispersion of primary TRC, TRN and/or TRC/N precipitates. The amorphous particulates are heated above the crystallization temperature of the base alloy composition to nucleate and grow a hard magnetic phase to an optimum grain size and to form secondary TRC, TRN and/or TRC/N precipitates dispersed at grain boundaries. The crystallized particulates are consolidated at an elevated temperature to form a shape. During elevated temperature consolidation, the primary and secondary precipitates act to pin the grain boundaries and minimize deleterious grain growth that is harmful to magnetic properties. 33 figs.

  7. Carbide/nitride grain refined rare earth-iron-boron permanent magnet and method of making

    DOE Patents [OSTI]

    McCallum, R. William (Ames, IA); Branagan, Daniel J. (Ames, IA)

    1996-01-23

    A method of making a permanent magnet wherein 1) a melt is formed having a base alloy composition comprising RE, Fe and/or Co, and B (where RE is one or more rare earth elements) and 2) TR (where TR is a transition metal selected from at least one of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, and Al) and at least one of C and N are provided in the base alloy composition melt in substantially stoichiometric amounts to form a thermodynamically stable compound (e.g. TR carbide, nitride or carbonitride). The melt is rapidly solidified in a manner to form particulates having a substantially amorphous (metallic glass) structure and a dispersion of primary TRC, TRN and/or TRC/N precipitates. The amorphous particulates are heated above the crystallization temperature of the base alloy composition to nucleate and grow a hard magnetic phase to an optimum grain size and to form secondary TRC, TRN and/or TRC/N precipitates dispersed at grain boundaries. The crystallized particulates are consolidated at an elevated temperature to form a shape. During elevated temperature consolidation, the primary and secondary precipitates act to pin the grain boundaries and minimize deleterious grain growth that is harmful to magnetic properties.

  8. Nitride based quantum well light-emitting devices having improved current injection efficiency

    DOE Patents [OSTI]

    Tansu, Nelson; Zhao, Hongping; Liu, Guangyu; Arif, Ronald

    2014-12-09

    A III-nitride based device provides improved current injection efficiency by reducing thermionic carrier escape at high current density. The device includes a quantum well active layer and a pair of multi-layer barrier layers arranged symmetrically about the active layer. Each multi-layer barrier layer includes an inner layer abutting the active layer; and an outer layer abutting the inner layer. The inner barrier layer has a bandgap greater than that of the outer barrier layer. Both the inner and the outer barrier layer have bandgaps greater than that of the active layer. InGaN may be employed in the active layer, AlInN, AlInGaN or AlGaN may be employed in the inner barrier layer, and GaN may be employed in the outer barrier layer. Preferably, the inner layer is thin relative to the other layers. In one embodiment the inner barrier and active layers are 15 .ANG. and 24 .ANG. thick, respectively.

  9. Direct growth of nanocrystalline hexagonal boron nitride films on dielectric substrates

    SciTech Connect (OSTI)

    Tay, Roland Yingjie; Tsang, Siu Hon; Loeblein, Manuela; Chow, Wai Leong; Loh, Guan Chee; Toh, Joo Wah; Ang, Soon Loong; Teo, Edwin Hang Tong

    2015-03-09

    Atomically thin hexagonal-boron nitride (h-BN) films are primarily synthesized through chemical vapor deposition (CVD) on various catalytic transition metal substrates. In this work, a single-step metal-catalyst-free approach to obtain few- to multi-layer nanocrystalline h-BN (NCBN) directly on amorphous SiO{sub 2}/Si and quartz substrates is demonstrated. The as-grown thin films are continuous and smooth with no observable pinholes or wrinkles across the entire deposited substrate as inspected using optical and atomic force microscopy. The starting layers of NCBN orient itself parallel to the substrate, initiating the growth of the textured thin film. Formation of NCBN is due to the random and uncontrolled nucleation of h-BN on the dielectric substrate surface with no epitaxial relation, unlike on metal surfaces. The crystallite size is ?25?nm as determined by Raman spectroscopy. Transmission electron microscopy shows that the NCBN formed sheets of multi-stacked layers with controllable thickness from ?2 to 25?nm. The absence of transfer process in this technique avoids any additional degradation, such as wrinkles, tears or folding and residues on the film which are detrimental to device performance. This work provides a wider perspective of CVD-grown h-BN and presents a viable route towards large-scale manufacturing of h-BN substrates and for coating applications.

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

    SciTech Connect (OSTI)

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

    2014-07-21

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

  11. Radius stabilization and dark matter with a bulk Higgs in warped extra dimension

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

    Ahmed, A.; Grzadkowski, B.; Gunion, J. F.; Jiang, Y.

    2015-01-01

    In this study, we employ an SU(2) bulk Higgs doublet as the stabilization field in the Randall–Sundrum model with appropriate bulk and brane-localized potentials. The gauge hierarchy problem can be solved for an exponentially IR-localized Higgs background field with mild values of fundamental parameters of the 5D theory. We consider an IR–UV–IR background geometry with the 5D SM fields in the bulk such that all the fields have even and odd towers of KK-modes. The zero-mode 4D effective theory contains all the SM fields plus a stable scalar, which serves as a dark matter candidate.

  12. Electronic properties of III-nitride semiconductors: A first-principles investigation using the Tran-Blaha modified Becke-Johnson potential

    SciTech Connect (OSTI)

    Araujo, Rafael B. Almeida, J. S. de Ferreira da Silva, A.

    2013-11-14

    In this work, we use density functional theory to investigate the influence of semilocal exchange and correlation effects on the electronic properties of III-nitride semiconductors considering zinc-blende and wurtzite crystal structures. We find that the inclusion of such effects through the use of the Tran-Blaha modified Becke-Johnson potential yields an excellent description of the electronic structures of these materials giving energy band gaps which are systematically larger than the ones obtained with standard functionals such as the generalized gradient approximation. The discrepancy between the experimental and theoretical band gaps is then significantly reduced with semilocal exchange and correlation effects. However, the effective masses are overestimated in the zinc-blende nitrides, but no systematic trend is found in the wurtzite compounds. New results for energy band gaps and effective masses of zinc-blende and wurtzite indium nitrides are presented.

  13. All bulk and boundary unitary cubic curvature theories in three dimensions

    SciTech Connect (OSTI)

    Guellue, Ibrahim; Sisman, Tahsin Cagri; Tekin, Bayram

    2011-01-15

    We construct all the bulk and boundary unitary cubic curvature parity invariant gravity theories in three dimensions in (anti)-de Sitter spaces. For bulk unitarity, our construction is based on the principle that the free theory of the cubic curvature theory reduces to one of the three known unitary theories which are the cosmological Einstein-Hilbert theory, the quadratic theory of the scalar curvature, or the new massive gravity (NMG). Bulk and boundary unitarity in NMG is in conflict; therefore, cubic theories that are unitary both in the bulk and on the boundary have free theories that reduce to the other two alternatives. We also study the unitarity of the Born-Infeld extensions of NMG to all orders in curvature.

  14. Bulk glass formation in the Pd{endash}Ni{endash}P system

    SciTech Connect (OSTI)

    He, Y.; Schwarz, R.B.; Archuleta, J.I. [Center for Materials Science, MS K-765, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Center for Materials Science, MS K-765, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    1996-09-01

    Bulk amorphous Pd{endash}Ni{endash}P rods with diameters ranging from 10 to 25 mm were prepared by a fluxing technique over a wide composition range. For most bulk glassy alloys studied, the difference between the glass transition temperature and the crystallization temperature, {ital T}{sub {ital x}}{minus}{ital T}{sub {ital g}}, is larger than 90 K. Of all the alloy compositions examined, Pd{sub 40}Ni{sub 40}P{sub 20} has the highest glass formability, and 300-g bulk amorphous cylinders, 25 mm in diameter and 50 mm in length, were easily and repeatedly formed. This size, however, is not an upper limit. The elastic properties of these bulk amorphous alloys were determined by a resonant ultrasound spectroscopy technique.

  15. The effect of confinement on the crystalline microstructure of polymer: fullerene bulk heterojunctions

    SciTech Connect (OSTI)

    Ashraf, A.; Dissanayake, D. M. N. M.; Eisaman, M. D.

    2015-07-01

    We investigate the effect of confinement on the coherence length and the crystalline microstructure of the polymer component of polymer: fullerene bulk heterojunction thin films using grazing incidence wide angle x-ray scattering. We find that the polymer crystallite size decreases and the alignment of the molecules along the surface normal increases, as the thin-film thickness is reduced from 920nm to < 20nm and approaches the thin-film confinement regime. Furthermore, we find that the polymer crystallite size near the surface (air interface) is lower than the crystallite size in the bulk or the bottom (substrate interface) of bulk heterojunction films thicker than the confinement regime. Variation in polymer crystallite size can cause changes in charge carrier mobility and recombination rates, which in turn affect the performance of bulk heterojunction thin film devices such as photovoltaics and photodetectors

  16. Correlation Between Structure and Thermoelectric Properties of Bulk High Performance Materials for Energy Conversion

    Broader source: Energy.gov [DOE]

    Rapid solidified precursor converted into crystalline bulks under pressure produced thermoelectric materials of nano-sized grains with strongly coupled grain boundaries, achieving reduced lattice thermal conductivity and increased power factor

  17. The Role of Surface Chemistry and Bulk Properties on the Cycling...

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

    More Documents & Publications The Role of Surface Chemistry and Bulk Properties on the ... Energy Storage R&D The Role of Surface Chemistry on the Cycling and Rate Capability of ...

  18. Residential Bulk-Fed Wood-Pellet Central Boilers and Furnace Rebate Program

    Broader source: Energy.gov [DOE]

    The New Hampshire Public Utilities Commission (PUC) is offering rebates of 30% of the installed cost of qualifying new residential bulk-fed, wood-pellet central heating boilers or furnaces. The...

  19. The effect of confinement on the crystalline microstructure of polymer: fullerene bulk heterojunctions

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

    Ashraf, A.; Dissanayake, D. M. N. M.; Eisaman, M. D.

    2015-07-01

    We investigate the effect of confinement on the coherence length and the crystalline microstructure of the polymer component of polymer: fullerene bulk heterojunction thin films using grazing incidence wide angle x-ray scattering. We find that the polymer crystallite size decreases and the alignment of the molecules along the surface normal increases, as the thin-film thickness is reduced from 920nm to < 20nm and approaches the thin-film confinement regime. Furthermore, we find that the polymer crystallite size near the surface (air interface) is lower than the crystallite size in the bulk or the bottom (substrate interface) of bulk heterojunction films thickermore » than the confinement regime. Variation in polymer crystallite size can cause changes in charge carrier mobility and recombination rates, which in turn affect the performance of bulk heterojunction thin film devices such as photovoltaics and photodetectors« less

  20. In-situ study of crystallization kinetics in ternary bulk metallic glass

    Office of Scientific and Technical Information (OSTI)

    alloys with different glass forming abilities (Journal Article) | DOE PAGES In-situ study of crystallization kinetics in ternary bulk metallic glass alloys with different glass forming abilities « Prev Next » Title: In-situ study of crystallization kinetics in ternary bulk metallic glass alloys with different glass forming abilities Authors: Lan, Si [1] ; Wei, Xiaoya [1] ; Zhou, Jie [2] ; Lu, Zhaoping [2] ; Wu, Xuelian [1] ; Feygenson, Mikhail [3] ; Neuefeind, Jörg [3] ; Wang, Xun-Li [1]

  1. Lithium Ion Solvation and Diffusion in Bulk Organic Electrolytes from First

    Office of Scientific and Technical Information (OSTI)

    Principles Molecular Dynamics (Conference) | SciTech Connect Lithium Ion Solvation and Diffusion in Bulk Organic Electrolytes from First Principles Molecular Dynamics Citation Details In-Document Search Title: Lithium Ion Solvation and Diffusion in Bulk Organic Electrolytes from First Principles Molecular Dynamics Authors: Ong, M T ; Lordi, V ; Draeger, E W ; Pask, J E Publication Date: 2014-11-05 OSTI Identifier: 1178391 Report Number(s): LLNL-PROC-663811 DOE Contract Number:

  2. Lithium Ion Solvation and Diffusion in Bulk Organic Electrolytes from First

    Office of Scientific and Technical Information (OSTI)

    Principles and Classical Reactive Molecular Dynamics (Journal Article) | SciTech Connect Journal Article: Lithium Ion Solvation and Diffusion in Bulk Organic Electrolytes from First Principles and Classical Reactive Molecular Dynamics Citation Details In-Document Search Title: Lithium Ion Solvation and Diffusion in Bulk Organic Electrolytes from First Principles and Classical Reactive Molecular Dynamics Authors: Ong, M T ; Verners, O ; Draeger, E W ; van Duin, A ; Lordi, V ; Pask, J E

  3. Lithium Ion Solvation and Diffusion in Bulk Organic Electrolytes from First

    Office of Scientific and Technical Information (OSTI)

    Principles and Classical Reactive Molecular Dynamics (Journal Article) | SciTech Connect Journal Article: Lithium Ion Solvation and Diffusion in Bulk Organic Electrolytes from First Principles and Classical Reactive Molecular Dynamics Citation Details In-Document Search Title: Lithium Ion Solvation and Diffusion in Bulk Organic Electrolytes from First Principles and Classical Reactive Molecular Dynamics × You are accessing a document from the Department of Energy's (DOE) SciTech Connect.

  4. Surface magnetism of Gd(0001): Evidence of ferromagnetic coupling to bulk

    SciTech Connect (OSTI)

    Mulhollan, G.A.; Garrison, K.; Erskine, J.L. )

    1992-11-30

    Previous polarized electron experiments and recent {ital ab} {ital initio} calculations suggest that the surface layer magnetic moments of Gd(0001) are antiferromagnetically coupled to the bulk magnetic moments. Spin-polarized photoemission data are presented which show that the spin polarization of the magnetic surface state and the surface 4{ital f} states of Gd(0001) are coupled ferromagnetically to the bulk magnetic moment.

  5. The Role of Additive in Diketopyrrolopyrrole-based Small Molecular Bulk

    Office of Scientific and Technical Information (OSTI)

    Heterojunction Solar Cells (Journal Article) | SciTech Connect Journal Article: The Role of Additive in Diketopyrrolopyrrole-based Small Molecular Bulk Heterojunction Solar Cells Citation Details In-Document Search Title: The Role of Additive in Diketopyrrolopyrrole-based Small Molecular Bulk Heterojunction Solar Cells Authors: Wang, Hongyu ; Liu, Feng ; Bu, Laju ; Gao, Jun ; Wang, Cheng ; Wei, Wei ; Russell, Thomas P. Publication Date: 2013-08-29 OSTI Identifier: 1160446 DOE Contract

  6. Thermal Conductivity Measurements of Bulk Thermoelectric Materials (Prop. 2004-067)

    SciTech Connect (OSTI)

    Wang, Hsin; Porter, Wallace D; Sharp, J

    2006-01-01

    Thermal conductivity is an important material property of the bulk thermoelectrics. To improve ZT a reduced thermal conductivity is always desired. However, there is no standard material for thermoelectrics and the test results, even on the same material, often show significant scatter. The scatter in thermal conductivity made reported ZT values uncertain and sometime unrepeatable. One of the reasons for the uncertainty is due to the microstructure differences resulting from sintering, heat treatment and other processing parameters. They selected commonly used bulk thermoelectric materials and conducted thermal conductivity measurements using the laser flash diffusivity and differential scanning calorimeter (DSC) systems. Thermal conductivity was measured as a function of temperature of temperature from room temperature to 500 K and back to room temperature. The effect of thermal cycling on the bulk thermoelectric was studied. Comnbined with measurements on electrical resistivity and Seebeck coefficient, they show the use of a ZT map in selecting thermoelectrics. The commercial bulk material showed very good consistency and reliability compared to other bulk materials. The goal is to develop a thermal transport properties database for the bulk thermoelectrics and make the information available to the research community and industry.

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

    DOE Patents [OSTI]

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

    2005-02-01

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

  8. Precipitation of aluminum nitride in a high strength maraging steel with low nitrogen content

    SciTech Connect (OSTI)

    Jeanmaire, G.; Dehmas, M.; Redjamia, A.; Puech, S.; Fribourg, G.

    2014-12-15

    In the present work, aluminum nitride (AlN) precipitation was investigated in a X23NiCoCrMoAl13-6-3 maraging steel with low nitrogen content (wt.% N = 5.5 ppm). A reliable and robust automatic method by scanning electron microscopy observations coupled with energy dispersive X-ray spectroscopy was developed for the quantification of AlN precipitates. The first stage was to identify the solvus temperature and to develop a heat treatment able to dissolve the AlN precipitates. The experimental determination of equilibrium conditions and solvus temperature show good agreement with ThermoCalc simulation. Then, from this AlN-free state, the cooling rate, isothermal holding time and temperature were the subject of an intensive investigation in the austenite region of this maraging steel. In spite of the high temperatures used during heat treatments, the growth kinetic of the largest AlN precipitates (> 1 ?m) is slow. The cooling rate has a major effect on the size and the number density of AlN due to a higher driving force for nucleation at low temperatures. At last, quenching prior to isothermal annealing at high temperatures leads to fine and dense AlN precipitation, resulting from the martensite to austenite transformation. Experimental results will be discussed and compared with kinetic data obtained with the mobility database MobFe2 implemented in Dictra software. - Highlights: Slow dissolution kinetic of AlN precipitates due to both their large size and small chemical driving force Significant effects of cooling rate prior isothermal heat treatment, holding time and temperature on AlN precipitation Size of AlN precipitates can be reduced by quenching prior isothermal holding. Fine precipitation of AlN related to the ? ? ? transformation.

  9. Thermal oxidation of polycrystalline and single crystalline aluminum nitride wafers (Prop 2003-054)

    SciTech Connect (OSTI)

    Speakman, Scott A; Gu, Z; Edgar, J H; Blom, Douglas Allen; Perrin, J; Chaudhuri, J

    2006-10-01

    Two types of aluminum nitride (AlN) samples were oxidized in flowing oxygen between 900 C and 1150 C for up to 6 h - highly (0001) textured polycrystalline AlN wafers and low defect density AlN single crystals. The N-face consistently oxidized at a faster rate than the Al-face. At 900 C and 1000 C after 6 h, the oxide was 15% thicker on the N-face than on the Al-face of polycrystalline AlN. At 1100 C and 1150 C, the oxide was only 5% thicker on the N-face, as the rate-limiting step changed from kinetically-controlled to diffusion-controlled with the oxide thickness. A linear parabolic model was established for the thermal oxidation of polycrystalline AlN on both the Al- and N-face. Transmission electron microscopy (TEM) confirmed the formation of a thicker crystalline oxide film on the N-face than on the Al-face, and established the crystallographic relationship between the oxide film and substrate. The oxidation of high-quality AlN single crystals resulted in a more uniform colored oxide layer compared to polycrystalline AlN. The aluminum oxide layer was crystalline with a rough AlN/oxide interface. The orientation relationship between AlN and Al{sub 2}O{sub 3} was (0001) AlN//(10{bar 1}0) Al{sub 2}O{sub 3} and (1{bar 1}00) AlN//(01{bar 1}2) Al{sub 2}O{sub 3}.

  10. Electrolysis of uranium nitride containing fission product elements (Mo, Pd, Nd) in a molten LiCl-KCl eutectic

    SciTech Connect (OSTI)

    Satoh, Takumi; Iwai, Takashi; Arai, Yasuo

    2007-07-01

    The electrolysis of burnup-simulated uranium nitride, UN, containing representative solid fission product elements (Mo, Pd, Nd) was investigated in the molten LiCl-KCl eutectic salt with 0.54 wt% UCl{sub 3} from the view point of application of pyrochemical reprocessing to nitride fuel cycle. It was found from cyclic voltammetry and anodic polarization curve measurement that anodic dissolution of UN began at about -0.75 V vs. Ag/AgCl reference electrode in all samples. After the electrolysis at the constant anodic potential of -0.65 {approx} -0.60 V vs. Ag/AgCl, most of UN was dissolved into LiCl- KCl as UCl{sub 3} at the anode, and U was recovered in the liquid Cd cathode in all samples. Further, Nd was dissolved into LiCl-KCl as NdCl{sub 3}, while Mo and Pd were not dissolved but remained at the anode. (authors)

  11. Preliminary design study of small long life boiling water reactor (BWR) with tight lattice thorium nitride fuel

    SciTech Connect (OSTI)

    Trianti, Nuri E-mail: szaki@fi.itba.c.id; Su'ud, Zaki E-mail: szaki@fi.itba.c.id; Arif, Idam E-mail: szaki@fi.itba.c.id; Riyana, EkaSapta

    2014-09-30

    Neutronic performance of small long-life boiling water reactors (BWR) with thorium nitride based fuel has been performed. A recent study conducted on BWR in tight lattice environments (with a lower moderator percentage) produces small power reactor which has some specifications, i.e. 10 years operation time, power density of 19.1 watt/cc and maximum excess reactivity of about 4%. This excess reactivity value is smaller than standard reactivity of conventional BWR. The use of hexagonal geometry on the fuel cell of BWR provides a substantial effect on the criticality of the reactor to obtain a longer operating time. Supported by a tight concept lattice where the volume fraction of the fuel is greater than the moderator and fuel, Thorium Nitride give good results for fuel cell design on small long life BWR. The excess reactivity of the reactor can be reduced with the addition of gadolinium as burnable poisons. Therefore the hexagonal tight lattice fuel cell design of small long life BWR that has a criticality more than 20 years of operating time has been obtained.

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

    SciTech Connect (OSTI)

    Flynn, Kristen

    2015-08-18

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

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

    SciTech Connect (OSTI)

    Flynn, Kristen

    2015-08-19

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

  14. Evaluation of bulk paint worker exposure to solvents at household hazardous waste collection events

    SciTech Connect (OSTI)

    Cameron, M.

    1995-09-01

    In fiscal year 93/94, over 250 governmental agencies were involved in the collection of household hazardous wastes in the State of California. During that time, over 3,237,000 lbs. of oil based paint were collected in 9,640 drums. Most of this was in lab pack drums, which can only hold up to 20 one gallon cans. Cost for disposal of such drums is approximately $1000. In contrast, during the same year, 1,228,000 lbs. of flammable liquid were collected in 2,098 drums in bulk form. Incineration of bulked flammable liquids is approximately $135 per drum. Clearly, it is most cost effective to bulk flammable liquids at household hazardous waste events. Currently, this is the procedure used at most Temporary Household Hazardous Waste Collection Facilities (THHWCFs). THHWCFs are regulated by the Department of Toxic Substances Control (DTSC) under the new Permit-by Rule Regulations. These regulations specify certain requirements regarding traffic flow, emergency response notifications and prevention of exposure to the public. The regulations require that THHWCF operators bulk wastes only when the public is not present. [22 CCR, section 67450.4 (e) (2) (A)].Santa Clara County Environmental Health Department sponsors local THHWCF`s and does it`s own bulking. In order to save time and money, a variance from the regulation was requested and an employee monitoring program was initiated to determine actual exposure to workers. Results are presented.

  15. Dual mechanical behaviour of hydrogen in stressed silicon nitride thin films

    SciTech Connect (OSTI)

    Volpi, F. Braccini, M.; Pasturel, A.; Devos, A.; Raymond, G.; Morin, P.

    2014-07-28

    In the present article, we report a study on the mechanical behaviour displayed by hydrogen atoms and pores in silicon nitride (SiN) films. A simple three-phase model is proposed to relate the physical properties (stiffness, film stress, mass density, etc.) of hydrogenated nanoporous SiN thin films to the volume fractions of hydrogen and pores. This model is then applied to experimental data extracted from films deposited by plasma enhanced chemical vapour deposition, where hydrogen content, stress, and mass densities range widely from 11% to 30%, ?2.8 to 1.5?GPa, and 2.0 to 2.8?g/cm{sup 3}, respectively. Starting from the conventional plotting of film's Young's modulus against film porosity, we first propose to correct the conventional calculation of porosity volume fraction with the hydrogen content, thus taking into account both hydrogen mass and concentration. The weight of this hydrogen-correction is found to evolve linearly with hydrogen concentration in tensile films (in accordance with a simple mass correction of the film density calculation), but a clear discontinuity is observed toward compressive stresses. Then, the effective volume occupied by hydrogen atoms is calculated taking account of the bond type (N-H or Si-H bonds), thus allowing a precise extraction of the hydrogen volume fraction. These calculations applied to tensile films show that both volume fractions of hydrogen and porosity are similar in magnitude and randomly distributed against Young's modulus. However, the expected linear dependence of the Young's modulus is clearly observed when both volume fractions are added. Finally, we show that the stiffer behaviour of compressive films cannot be only explained on the basis of this (hydrogen?+?porosity) volume fraction. Indeed this stiffness difference relies on a dual mechanical behaviour displayed by hydrogen atoms against the film stress state: while they participate to the stiffness in compressive films, hydrogen atoms mainly behave like pores in tensile films where they do not participate to the film stiffness.

  16. Linking structure to fragility in bulk metallic glass-forming liquids

    SciTech Connect (OSTI)

    Wei, Shuai E-mail: m.stolpe@mx.uni-saarland.de; Stolpe, Moritz E-mail: m.stolpe@mx.uni-saarland.de; Gross, Oliver; Gallino, Isabella; Hembree, William; Busch, Ralf; Evenson, Zach; Bednarcik, Jozef; Kruzic, Jamie J.

    2015-05-04

    Using in-situ synchrotron X-ray scattering, we show that the structural evolution of various bulk metallic glass-forming liquids can be quantitatively connected to their viscosity behavior in the supercooled liquid near T{sub g}. The structural signature of fragility is identified as the temperature dependence of local dilatation on distinct key atomic length scales. A more fragile behavior results from a more pronounced thermally induced dilatation of the structure on a length scale of about 3 to 4 atomic diameters, coupled with shallower temperature dependence of structural changes in the nearest neighbor environment. These findings shed light on the structural origin of viscous slowdown during undercooling of bulk metallic glass-forming liquids and demonstrate the promise of predicting the properties of bulk metallic glasses from the atomic scale structure.

  17. Bulk single crystal ternary substrates for a thermophotovoltaic energy conversion system

    DOE Patents [OSTI]

    Charache, G.W.; Baldasaro, P.F.; Nichols, G.J.

    1998-06-23

    A thermophotovoltaic energy conversion device and a method for making the device are disclosed. The device includes a substrate formed from a bulk single crystal material having a bandgap (E{sub g}) of 0.4 eV < E{sub g} < 0.7 eV and an emitter fabricated on the substrate formed from one of a p-type or an n-type material. Another thermophotovoltaic energy conversion device includes a host substrate formed from a bulk single crystal material and lattice-matched ternary or quaternary III-V semiconductor active layers. 12 figs.

  18. Solar Cells: Spin-Cast Bulk Heterojunction Solar Cells: A Dynamical

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

    Investigation Solar Cells: Spin-Cast Bulk Heterojunction Solar Cells: A Dynamical Investigation Solar Cells: Spin-Cast Bulk Heterojunction Solar Cells: A Dynamical Investigation Print Wednesday, 03 April 2013 13:32 Spin-coating is extensively used in the lab-based manufacturing of organic solar cells, including most of the record-setting cells. Aram Amassian and co-workers report in this study the first direct observation of photoactive layer formation as it occurs during spin-coating. The

  19. Bulk single crystal ternary substrates for a thermophotovoltaic energy conversion system

    DOE Patents [OSTI]

    Charache, Greg W. (Clifton Park, NY); Baldasaro, Paul F. (Clifton Park, NY); Nichols, Greg J. (Burnt Hills, NY)

    1998-01-01

    A thermophotovoltaic energy conversion device and a method for making the device. The device includes a substrate formed from a bulk single crystal material having a bandgap (E.sub.g) of 0.4 eVbulk single crystal material and lattice-matched ternary or quaternary III-V semiconductor active layers.

  20. Role of phase instabilities in the early response of bulk fused silica

    Office of Scientific and Technical Information (OSTI)

    during laser-induced breakdown (Journal Article) | SciTech Connect Role of phase instabilities in the early response of bulk fused silica during laser-induced breakdown Citation Details In-Document Search Title: Role of phase instabilities in the early response of bulk fused silica during laser-induced breakdown Authors: DeMange, P. ; Negres, R. A. ; Raman, R. N. ; Colvin, J. D. ; Demos, S. G. Publication Date: 2011-08-17 OSTI Identifier: 1100571 Type: Publisher's Accepted Manuscript Journal