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Note: This page contains sample records for the topic "bulk gallium nitride" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
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We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

P-type gallium nitride  

DOE Patents [OSTI]

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.

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

1997-08-12T23:59:59.000Z

2

P-type gallium nitride  

DOE Patents [OSTI]

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.

Rubin, Michael (Berkeley, CA); Newman, Nathan (Montara, CA); Fu, Tracy (Berkeley, CA); Ross, Jennifer (Pleasanton, CA); Chan, James (Berkeley, CA)

1997-01-01T23:59:59.000Z

3

Au-free Ohmic Contacts to Gallium Nitride and Graphene  

E-Print Network [OSTI]

This work deals with Au-free contact metallization schemes for gallium nitride (GaN) and graphene semiconductors. Graphene and gallium nitride are promising materials that can potentially be integrated together in the near future for high frequency...

Ravikirthi, Pradhyumna

2014-08-10T23:59:59.000Z

4

Characterizing organometallic-vapor-phase-epitaxy-grown indium gallium nitride islands on gallium nitride for light emitting diode applications.  

E-Print Network [OSTI]

??The indium-gallium-nitride on gallium-nitride (InGaN/GaN) materials system is a promising candidate for providing a high intensity, high efficiency solution to the yet unsolved problem of… (more)

Anderson, Kathy Perkins Jenkins

2011-01-01T23:59:59.000Z

5

Gallium nitride junction field-effect transistor  

DOE Patents [OSTI]

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.

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

1999-01-01T23:59:59.000Z

6

Synthesis and characterization of visible emission from rare-earth doped aluminum nitride, gallium nitride and gallium aluminum nitride powders and thin films  

E-Print Network [OSTI]

of the Nitrides of Aluminum and Gallium," J. Electrochem.1) 24 (1962). G. Long and L. M. Foster, "Aluminum Nitride, aRefractory for Aluminum to 2000°C," J. Am. Ceram. Soc. ,

Tao, Jonathan Huai-Tse

2010-01-01T23:59:59.000Z

7

Neutron detection using boron gallium nitride semiconductor material  

SciTech Connect (OSTI)

In this study, we developed a new neutron-detection device using a boron gallium nitride (BGaN) semiconductor in which the B atom acts as a neutron converter. BGaN and gallium nitride (GaN) samples were grown by metal organic vapor phase epitaxy, and their radiation detection properties were evaluated. GaN exhibited good sensitivity to ?-rays but poor sensitivity to ?-rays. Moreover, we confirmed that electrons were generated in the depletion layer under neutron irradiation. This resulted in a neutron-detection signal after ?-rays were generated by the capture of neutrons by the B atoms. These results prove that BGaN is useful as a neutron-detecting semiconductor material.

Atsumi, Katsuhiro [Department of Electrical and Electronic Engineering, Graduate School of Engineering, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8561 (Japan); Inoue, Yoku; Nakano, Takayuki, E-mail: ttnakan@ipc.shizuoka.ac.jp [Department of Electrical and Materials Science, Graduate School of Engineering, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8561 (Japan); Mimura, Hidenori; Aoki, Toru [Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8011 (Japan)

2014-03-01T23:59:59.000Z

8

arsenide gallium nitride: Topics by E-print Network  

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

Lundberga,*, J. Lua , A Abstract The diffusion of indium and gallium in polycrystalline thin film Cu(In,Ga)Se2 layers has been with a larger number of vacancies, that facilitates...

9

Advanced Epi Tools for Gallium Nitride Light Emitting Diode Devices  

SciTech Connect (OSTI)

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.

Patibandla, Nag; Agrawal, Vivek

2012-12-01T23:59:59.000Z

10

Distinctive Signature of Indium Gallium Nitride Quantum Dot Lasing in Microdisks Cavities  

E-Print Network [OSTI]

Low threshold lasers realized within compact, high quality optical cavities enable a variety of nanophotonics applications. Gallium nitride (GaN) materials containing indium gallium nitride (InGaN) quantum dots and quantum wells offer an outstanding platform to study light matter interactions and realize practical devices such as efficient light emitting diodes and nanolasers. Despite progress in the growth and characterization of InGaN quantum dots, their advantages as the gain medium in low threshold lasers have not been clearly demonstrated. This work seeks to better understand the reasons for these limitations by focusing on the simpler, limited-mode microdisk cavities, and by carrying out comparisons of lasing dynamics in those cavities using varying gain media including InGaN quantum wells, fragmented quantum wells, and a combination of fragmented quantum wells with quantum dots. For each gain medium, we utilize the distinctive, high quality (Q~5500) modes of the cavities, and the change in the highest ...

Woolf, Alexander; Aharanovich, Igor; Zhu, Tongtong; Niu, Nan; Wang, Danqing; Oliver, Rachel A; Hu, Evelyn L

2014-01-01T23:59:59.000Z

11

High-Quality, Low-Cost Bulk Gallium Nitride Substrates  

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

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12

Light-Emitting Diodes on Semipolar Bulk Gallium Nitride Substrate |  

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

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13

Formation mechanisms of spatially-directed zincblende gallium nitride nanocrystals  

SciTech Connect (OSTI)

We report on the spatially selective formation of GaN nanocrystals embedded in GaAs. Broad-area N{sup +} implantation followed by rapid thermal annealing leads to the formation of nanocrystals at the depth of maximum ion damage. With additional irradiation using a Ga{sup +} focused ion beam, selective lateral positioning of the nanocrystals within the GaAs matrix is observed in isolated regions of increased vacancy concentration. Following rapid thermal annealing, the formation of zincblende GaN is observed in the regions of highest vacancy concentration. The nucleation of zincblende nanocrystals over the wurtzite phase of bulk GaN is consistent with the predictions of a thermodynamic model for the nanoscale size-dependence of GaN nucleation.

Wood, A. W. [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States); Collino, R. R. [Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); Cardozo, B. L. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); Naab, F. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States); Wang, Y. Q. [Materials Science and Technology Division, Los Alamos National Lab, Los Alamos, New Mexico 87545 (United States); Goldman, R. S. [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States); Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2011-12-15T23:59:59.000Z

14

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

SciTech Connect (OSTI)

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.

Imtiaz, Atif [Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, Colorado 80305 (United States); Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, Colorado 80309 (United States); Wallis, Thomas M.; Brubaker, Matt D.; Blanchard, Paul T.; Bertness, Kris A.; Sanford, Norman A.; Kabos, Pavel, E-mail: kabos@boulder.nist.gov [Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, Colorado 80305 (United States); Weber, Joel C. [Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, Colorado 80305 (United States); Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309 (United States); Coakley, Kevin J. [Information Technology Laboratory, National Institute of Standards and Technology, Boulder, Colorado 80305 (United States)

2014-06-30T23:59:59.000Z

15

More Efficient Power Conversion for EVs: Gallium-Nitride Advanced Power Semiconductor and Packaging  

SciTech Connect (OSTI)

Broad Funding Opportunity Announcement Project: Delphi is developing power converters that are smaller and more energy efficient, reliable, and cost-effective than current power converters. Power converters rely on power transistors which act like a very precisely controlled on-off switch, controlling the electrical energy flowing through an electrical circuit. Most power transistors today use silicon (Si) semiconductors. However, Delphi is using semiconductors made with a thin layer of gallium-nitride (GaN) applied on top of the more conventional Si material. The GaN layer increases the energy efficiency of the power transistor and also enables the transistor to operate at much higher temperatures, voltages, and power-density levels compared to its Si counterpart. Delphi is packaging these high-performance GaN semiconductors with advanced electrical connections and a cooling system that extracts waste heat from both sides of the device to further increase the device’s efficiency and allow more electrical current to flow through it. When combined with other electronic components on a circuit board, Delphi’s GaN power transistor package will help improve the overall performance and cost-effectiveness of HEVs and EVs.

None

2010-02-01T23:59:59.000Z

16

Radiation tolerance of piezoelectric bulk single-crystal aluminum nitride  

SciTech Connect (OSTI)

For practical use in harsh radiation environments, we pose selection criteria for piezoelectric materials for nondestructive evaluation (NDE) and material characterization. Using these criteria, piezoelectric aluminum nitride is shown to be an excellent candidate. The results of tests on an aluminumnitride-based transducer operating in a nuclear reactor are also presented. We demonstrate the tolerance of single-crystal piezoelectric aluminum nitride after fast and thermal neutron fluences of 1.85 × 1018 neutron/cm2 and 5.8 × 1018 neutron/cm2, respectively, and a gamma dose of 26.8 MGy. The radiation hardness of AlN is most evident from the unaltered piezoelectric coefficient d33, which measured 5.5 pC/N after a fast and thermal neutron exposure in a nuclear reactor core for over 120 MWh, in agreement with the published literature value. The results offer potential for improving reactor safety and furthering the understanding of radiation effects on materials by enabling structural health monitoring and NDE in spite of the high levels of radiation and high temperatures, which are known to destroy typical commercial ultrasonic transducers.

David A. Parks; Bernhard R. Tittmann

2014-07-01T23:59:59.000Z

17

Investigation on properties of ultrafast switching in a bulk gallium arsenide avalanche semiconductor switch  

SciTech Connect (OSTI)

Properties of ultrafast switching in a bulk gallium arsenide (GaAs) avalanche semiconductor switch based on semi-insulating wafer, triggered by an optical pulse, were analyzed using physics-based numerical simulations. It has been demonstrated that when a voltage with amplitude of 5.2?kV is applied, after an exciting optical pulse with energy of 1??J arrival, the structure with thickness of 650??m reaches a high conductivity state within 110 ps. Carriers are created due to photons absorption, and electrons and holes drift to anode and cathode terminals, respectively. Static ionizing domains appear both at anode and cathode terminals, and create impact-generated carriers which contribute to the formation of electron-hole plasma along entire channel. When the electric field in plasma region increases above the critical value (?4?kV/cm) at which the electrons drift velocity peaks, a domain comes into being. An increase in carrier concentration due to avalanche multiplication in the domains reduces the domain width and results in the formation of an additional domain as soon as the field outside the domains increases above ?4?kV/cm. The formation and evolution of multiple powerfully avalanching domains observed in the simulations are the physical reasons of ultrafast switching. The switch exhibits delayed breakdown with the characteristics affected by biased electric field, current density, and optical pulse energy. The dependence of threshold energy of the exciting optical pulse on the biased electric field is discussed.

Hu, Long, E-mail: hulong-1226@126.com [Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi'an Jiaotong University, Xi'an 710049 (China); Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an 710024 (China); Su, Jiancang; Ding, Zhenjie; Hao, Qingsong; Yuan, Xuelin [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an 710024 (China)

2014-03-07T23:59:59.000Z

18

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

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

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19

Heat treatment of bulk gallium arsenide using a phosphosilicate glass cap  

SciTech Connect (OSTI)

n-type bulk GaAs crystals, capped with chemically vapor-deposited phosphosilicate glass, were heat treated at temperatures in the range of 600 to 950 /sup 0/C. Measurements on Schottky diodes and solar cells fabricated on the heat-treated material, after removal of a damaged surface layer, show an increase in free-carrier concentration, in minority-carrier-diffusion length, and in solar-cell short-circuit current. The observed changes are attributed to a removal of lifetime-reducing acceptorlike impurities, defects, or their complexes.

Mathur, G.; Wheaton, M.L.; Borrego, J.M.; Ghandhi, S.K.

1985-05-15T23:59:59.000Z

20

E-Print Network 3.0 - adaptive nitride-based coatings Sample...  

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

DELAUSANNE Summary: AND ELECTRONICS PROF. N. GRANDJEAN 33 III-NITRIDE BASED OPTOELECTRONIC DEVICES 34 GALLIUM NITRIDE-BASED 2D... FOR DIVERSE APPLICATIONS 84 HOLE ARRAY...

Note: This page contains sample records for the topic "bulk gallium nitride" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

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

E-Print Network [OSTI]

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

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

2014-01-01T23:59:59.000Z

22

Sandia National Laboratories: gallium nitride  

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

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23

Superconducting structure with layers of niobium nitride and aluminum nitride  

DOE Patents [OSTI]

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.

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

1989-01-01T23:59:59.000Z

24

Superconducting structure with layers of niobium nitride and aluminum nitride  

DOE Patents [OSTI]

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.

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

1989-07-04T23:59:59.000Z

25

Electronic properties of gallium nitride nanowires  

E-Print Network [OSTI]

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

Yoon, Joonah

2008-01-01T23:59:59.000Z

26

Copper Indium Gallium Diselenide  

Broader source: Energy.gov [DOE]

DOE-sponsored research on copper indium gallium diselenide [Cu(InxGa1-x)Se2], or CIGS, solar cells focuses on developing better film qualities, and thus, higher efficiencies. A list of current...

27

Group III-nitride thin films grown using MBE and bismuth  

DOE Patents [OSTI]

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.

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

2000-01-01T23:59:59.000Z

28

Group III-nitride thin films grown using MBE and bismuth  

DOE Patents [OSTI]

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.

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

2002-01-01T23:59:59.000Z

29

Nitrided Metallic Bipolar Plates  

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

nitrided surface treatment. In this approach, an electrically-conductive and corrosion-resistant chromium-nitride surface layer is formed on the bipolar plate component by...

30

Gallium interactions with Zircaloy  

E-Print Network [OSTI]

of weapons-grade plutonium (WGPu) in the United States is the conversion of weapons-grade plutonium into mixed-oxide (MOX) reactor fuel. MOX fuel fabricated in this way must be compatible with currently used nuclear fuel components. Since US WGPu contains... that gallium may have on zircaloy cladding during reactor operation. As a result of the reprocessing of spent fuel used in European nuclear programs, many studies have been conducted on the production and behavior of MOX fuel in traditional reactors [5...

West, Michael Keith

2012-06-07T23:59:59.000Z

31

Neutron irradiation effects on metal-gallium nitride contacts  

SciTech Connect (OSTI)

We have measured the effect of fast and thermal neutrons on GaN Schottky barriers and ohmic contacts using current–voltage and transmission line method electrical techniques, optical, atomic force and scanning electron microscopy morphological techniques, and X-ray photoemission spectroscopy chemical techniques. These studies reveal a 10{sup 15}?n/cm{sup 2} neutron threshold for Schottky barrier ideality factor increases, a 10{sup 15}?n/cm{sup 2} fast plus thermal neutron threshold for ohmic contact sheet and contact resistance increases, and 10{sup 16}?n/cm{sup 2} neutron fluence threshold for major device degradation identified with thermally driven diffusion of Ga and N into the metal contacts and surface phase changes. These results demonstrate the need for protecting metal-GaN contacts in device applications subject to neutron radiation.

Katz, Evan J.; Lin, Chung-Han; Zhang, Zhichun [Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Qiu, Jie; Cao, Lei [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Mishra, Umesh K. [Departments of Electrical and Computer Engineering and Materials Science and Engineering University of California, Santa Barbara, California 93106 (United States); Brillson, Leonard J., E-mail: brillson.1@osu.edu [Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Department of Physics and Center for Materials Research, The Ohio State University, Columbus, Ohio 43210 (United States)

2014-03-28T23:59:59.000Z

32

Neutron irradiation effects on gallium nitride-based Schottky diodes  

SciTech Connect (OSTI)

Depth-resolved cathodoluminescence spectroscopy (DRCLS), time-resolved surface photovoltage spectroscopy, X-ray photoemission spectroscopy (XPS), and current-voltage measurements together show that fast versus thermal neutrons differ strongly in their electronic and morphological effects on metal-GaN Schottky diodes. Fast and thermal neutrons introduce GaN displacement damage and native point defects, while thermal neutrons also drive metallurgical reactions at metal/GaN interfaces. Defect densities exhibit a threshold neutron fluence below which thermal neutrons preferentially heal versus create new native point defects. Scanning XPS and DRCLS reveal strong fluence- and metal-dependent electronic and chemical changes near the free surface and metal interfaces that impact diode properties.

Lin, Chung-Han; Katz, Evan J.; Zhang, Zhichun [Department of Electrical and Computer Engineering, The Ohio State University, Columbus Ohio 43210 (United States)] [Department of Electrical and Computer Engineering, The Ohio State University, Columbus Ohio 43210 (United States); Qiu, Jie; Cao, Lei [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, Ohio 43210 (United States)] [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Mishra, Umesh K. [Departments of Electrical and Computer Engineering and Materials Science and Engineering, University of California, Santa Barbara, California 93106 (United States)] [Departments of Electrical and Computer Engineering and Materials Science and Engineering, University of California, Santa Barbara, California 93106 (United States); Brillson, Leonard J. [Department of Electrical and Computer Engineering, The Ohio State University, Columbus Ohio 43210 (United States) [Department of Electrical and Computer Engineering, The Ohio State University, Columbus Ohio 43210 (United States); Department of Physics and Center for Materials Research, The Ohio State University, Columbus, Ohio 43210 (United States)

2013-10-14T23:59:59.000Z

33

Electrochemical Solution Growth: Gallium Nitride Crystal Growth - Energy  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsing Zirconia Nanoparticles as Selective Sorbents . | EMSL forInnovation

34

Gallium Safety in the Laboratory  

SciTech Connect (OSTI)

A university laboratory experiment for the US Department of Energy magnetic fusion research program required a simulant for liquid lithium. The simulant choices were narrowed to liquid gallium and galinstan (Ga-In-Sn) alloy. Safety information on liquid gallium and galinstan were compiled, and the choice was made to use galinstan. A laboratory safety walkthrough was performed in the fall of 2002 to support the galinstan experiment. The experiment has been operating successfully since early 2002.

Lee C. Cadwallader

2003-06-01T23:59:59.000Z

35

Gallium Safety in the Laboratory  

SciTech Connect (OSTI)

A university laboratory experiment for the US Department of Energy magnetic fusion research program required a simulant for liquid lithium. The simulant choices were narrowed to liquid gallium and galinstan (Ga-In-Sn) alloy. Safety information on liquid gallium and galinstan were compiled, and the choice was made to use galinstan. A laboratory safety walkthrough was performed in the fall of 2002 to support the galinstan experiment. The experiment has been operating successfully since early 2002.

Cadwallader, L.C.

2003-05-07T23:59:59.000Z

36

Corrosion behavior of mesoporous transition metal nitrides  

SciTech Connect (OSTI)

Transition metal nitrides (TMN) have many desirable characteristics such as high hardness and good thermal stability under reducing conditions. This work reports an initial survey of the chemical stability of mesoporous TMNs (TM=Nb, V, Cr and Ti) in water at 80 °C at neutral, acidic and alkaline pH. The mesoporous TMNs had specific surface areas of 25–60 m{sup 2}/g with average pore sizes ranging from 10 to 50 nm. The high surface areas of these materials enhance the rate of corrosion per unit mass over that of a bulk material, making detection of corrosion much easier. The products were characterized by Rietveld refinement of powder X-ray diffraction (PXRD) patterns and by scanning electron microscopy (SEM). Several nitrides have corrosion rates that are, within error, not distinguishable from zero (±1 Å/day). Of the nitrides examined, CrN appears to be the most corrosion resistant under acidic conditions. None of the nitrides studied are corrosion resistant under alkaline conditions. - Graphical abstract: Corrosion behavior of mesoporous transition metal nitrides (TM=Nb, V, Cr and Ti) in acidic and alkaline solutions at 80 °C for 2 weeks. Display Omitted - highlights: • Corrosion rates of mesoporous transition metal nitrides in aqueous solution is reported. • The mesoporous TMNs had surface areas of 25–60 m{sup 2}/g. • CrN is the most corrosion resistant under the conditions studied.

Yang, Minghui, E-mail: m.yang@cornell.edu [Department of Chemistry, Cornell University, Ithaca 14853-1301, NY (United States); Allen, Amy J.; Nguyen, Minh T. [Department of Chemistry, Cornell University, Ithaca 14853-1301, NY (United States); Ralston, Walter T. [College of Chemistry, University of California, Berkeley 94720-1460, CA (United States); MacLeod, Michelle J. [Department of Chemistry, Massachusetts Institute of Technology, Cambridge 02139-4307, MA (United States); DiSalvo, Francis J., E-mail: fjd3@cornell.edu [Department of Chemistry, Cornell University, Ithaca 14853-1301, NY (United States)

2013-09-15T23:59:59.000Z

37

Nitride fuel performance  

E-Print Network [OSTI]

The purpose of this work was to assess the potential of nitride fuels in the current context of the nuclear industry. Nitride fuels systems have indeed been for the past decade the subject of new interest from the international community...

Reynaud, Sylvie Marie Aurel?ie

2002-01-01T23:59:59.000Z

38

Pair distribution function study on compression of liquid gallium  

SciTech Connect (OSTI)

Integrating a hydrothermal diamond anvil cell (HDAC) and focused high energy x-ray beam from the superconductor wiggler X17 beamline at the National Synchrotron Light Source (NSLS) at the Brookhaven National Laboratory (BNL), we have successfully collected high quality total x-ray scattering data of liquid gallium. The experiments were conducted at a pressure range from 0.1GPa up to 2GPa at ambient temperature. For the first time, pair distribution functions (PDF) for liquid gallium at high pressure were derived up to 10 {angstrom}. Liquid gallium structure has been studied by x-ray absorption (Di Cicco & Filipponi, 1993; Wei et al., 2000; Comez et al., 2001), x-ray diffraction studies (Waseda & Suzuki, 1972), and molecular dynamics simulation (Tsay, 1993; Hui et al., 2002). These previous reports have focused on the 1st nearest neighbor structure, which tells us little about the atomic arrangement outside the first shell in non- crystalline materials. This study focuses on the structure of liquid gallium and the atomic structure change due to compression. The PDF results show that the observed atomic distance of the first nearest neighbor at 2.78 {angstrom} (first G(r) peak and its shoulder at the higher Q position) is consistent with previous studies by x-ray absorption (2.76 {angstrom}, Comez et al., 2001). We have also observed that the first nearest neighbor peak position did not change with pressure increasing, while the farther peaks positions in the intermediate distance range decreased with pressure increasing. This leads to a conclusion of the possible existence of 'locally rigid units' in the liquid. With the addition of reverse Monte Carlo modeling, we have observed that the coordination number in the local rigit unit increases with pressure. The bulk modulus of liquid gallium derived from the volume compression curve at ambient temperature (300K) is 12.1(6) GPa.

Luo, Shengnian [Los Alamos National Laboratory; Yu, Tony [SUNY-SB; Chen, Jiuhua [SUNY-SB; Ehm, Lars [SUNY-SB; Guo, Quanzhong [SUNY-SB; Parise, John [SUNY-SB

2008-01-01T23:59:59.000Z

39

Study of liquid gallium at high pressure using synchrotron x-ray  

SciTech Connect (OSTI)

Liquid gallium has been studied at high pressure up to 2 GPa and ambient temperature in a diamond anvil cell using high energy synchrotron x-ray beam. The total x-ray scattering data of liquid gallium were collected up to Q = 12 A{sup -1} and analyzed using pair distribution functions (PDF). The results indicate that the first nearest neighbor peak and second nearest neighbor (shoulder) peak of PDF in liquid gallium does not change with pressure, whereas the higher order (i.e., third and fourth) nearest neighbor peaks shift towards shorter distance with increasing pressure. Reverse Monte Carlo modeling based on the observed data shows that the coordination number in the liquid gallium increases with pressure from 10.5 at 0.3 GPa to 11.6 at 2 GPa. An atomic arrangement similar to the crystalline phase of Ga(II) with coordination number of 12 is proposed for the locally dense-packed rigid unit in liquid gallium. The volume compression data derived from the structure modeling yield a bulk modulus of 12.1(6) GPa for liquid gallium.

Yu, Tony; Guo Quanzhong; Parise, John [Department of Geosciences, Mineral Physics Institute, Stony Brook University, Stony Brook, New York 11794-2100 (United States); Chen Jiuhua [Department of Geosciences, Mineral Physics Institute, Stony Brook University, Stony Brook, New York 11794-2100 (United States); Department of Mechanical and Materials Engineering, Center for the Study of Matters at Extreme Conditions, Florida International University, Miami, Florida 33199 (United States); Ehm, Lars [Department of Geosciences, Mineral Physics Institute, Stony Brook University, Stony Brook, New York 11794-2100 (United States); National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States); Huang Shu [Department of Mechanical and Materials Engineering, Center for the Study of Matters at Extreme Conditions, Florida International University, Miami, Florida 33199 (United States); Luo Shengnian [Physics Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2012-06-01T23:59:59.000Z

40

Potential effects of gallium on cladding materials  

SciTech Connect (OSTI)

This paper identifies and examines issues concerning the incorporation of gallium in weapons derived plutonium in light water reactor (LWR) MOX fuels. Particular attention is given to the more likely effects of the gallium on the behavior of the cladding material. The chemistry of weapons grade (WG) MOX, including possible consequences of gallium within plutonium agglomerates, was assessed. Based on the calculated oxidation potentials of MOX fuel, the effect that gallium may have on reactions involving fission products and possible impact on cladding performance were postulated. Gallium transport mechanisms are discussed. With an understanding of oxidation potentials and assumptions of mechanisms for gallium transport, possible effects of gallium on corrosion of cladding were evaluated. Potential and unresolved issues and suggested research and development (R and D) required to provide missing information are presented.

Wilson, D.F.; Beahm, E.C.; Besmann, T.M.; DeVan, J.H.; DiStefano, J.R.; Gat, U.; Greene, S.R.; Rittenhouse, P.L.; Worley, B.A.

1997-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "bulk gallium nitride" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Synthesis, characterization, and biotemplated assembly of indium nitride and indium gallium nitride nanoparticles  

E-Print Network [OSTI]

A low-temperature, ambient pressure solution synthesis of colloidal InN nanoparticles is presented. This synthesis utilizes a previously dismissed precursor and results in individual, non-aggregated nanoparticles with ...

Hsieh, Jennifer Chia-Jen

2010-01-01T23:59:59.000Z

42

Energy Storage Systems 2010 Update Conference Presentations ...  

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

- Bulk Gallium Nitride Substrates - Karen Waldrip, SNL.pdf More Documents & Publications Energy Storage & Power Electronics 2008 Peer Review - Power Electronics (PE) Systems...

43

Local environment and composition of magnesium gallium layered...  

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

Local environment and composition of magnesium gallium layered double hydroxides determined from solid-state 1H and 71Ga NMR Local environment and composition of magnesium gallium...

44

Synthesis and characterization of visible emission from rare-earth doped aluminum nitride, gallium nitride and gallium aluminum nitride powders and thin films  

E-Print Network [OSTI]

74 (19) 2821 (1999). F. H. Spedding, Rare-earth Elements, inby the use of rare- earth elements as color emitters inpowders activated with rare-earth elements Eu 3+ , Tb 3+ ,

Tao, Jonathan Huai-Tse

2010-01-01T23:59:59.000Z

45

Synthesis and characterization of visible emission from rare-earth doped aluminum nitride, gallium nitride and gallium aluminum nitride powders and thin films  

E-Print Network [OSTI]

residential lighting using incandescent lights [2], as shownenergy used for the incandescent lamp is wasted as infraredlight source to replace incandescent lighting [1]. Figure

Tao, Jonathan Huai-Tse

2010-01-01T23:59:59.000Z

46

Synthesis, Crystal Structure, and Elastic Properties of Novel Tungsten Nitrides  

SciTech Connect (OSTI)

Among transition metal nitrides, tungsten nitrides possess unique and/or superior chemical, mechanical, and thermal properties. Preparation of these nitrides, however, is challenging because the incorporation of nitrogen into tungsten lattice is thermodynamically unfavorable at atmospheric pressure. To date, most materials in the W-N system are in the form of thin films produced by nonequilibrium processes and are often poorly crystallized, which severely limits their use in diverse technological applications. Here we report synthesis of tungsten nitrides through new approaches involving solid-state ion exchange and nitrogen degassing under pressure. We unveil a number of novel nitrides including hexagonal and rhombohedral W{sub 2}N{sub 3}. The final products are phase-pure and well-crystallized in bulk forms. For hexagonal W{sub 2}N{sub 3}, hexagonal WN, and cubic W3N4, they exhibit elastic properties rivaling or even exceeding cubic-BN. All four nitrides are prepared at a moderate pressure of 5 GPa, the lowest among high-pressure synthesis of transition metal nitrides, making it practically feasible for massive and industrial-scale production.

Wang, Shanmin; Yu, Xiaohui; Lin, Zhijun; Zhang, Ruifeng; He, Duanwei; Qin, Jiaqian; Zhu, Jinlong; Han, Jiantao; Wang, Lin; Mao, Ho-kwang; Zhang, Jianzhong; Zhao, Yusheng (UNLV); (Ehime U); (CIW); (Sichuan U.); (LANL)

2012-12-13T23:59:59.000Z

47

Boron nitride nanotubes  

DOE Patents [OSTI]

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.

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

2012-06-06T23:59:59.000Z

48

Recovery of gallium from aluminum industry residues  

SciTech Connect (OSTI)

A procedure is proposed to recover gallium from flue dust aluminum residues produced in plants by using solid-phase extraction with a commercial polyether-type polyurethane foam (PUF). Gallium can be separated from high concentrations of aluminum, iron, nickel, titanium, vanadium, copper, zinc, sulfate, fluoride, and chloride by extraction with PUF from 3 M sulfuric acid and 3 M sodium chloride concentration medium with at least a 92% efficiency. Gallium backextraction was fast and quantitative with ethanol solution. In all recovery steps commercial-grade reagents could be used, including tap water. The recovered gallium was precipitated with sodium hydroxide solution, purified by dissolution and precipitation, calcinated, and the final oxide was 98.6% pure.

Carvalho, M.S.; Neto, K.C.M.; Nobrega, A.W.; Medeiros, J.A.

2000-01-01T23:59:59.000Z

49

Nitrided Metallic Bipolar Plates  

SciTech Connect (OSTI)

The objectives are: (1) Develop and optimize stainless steel alloys amenable to formation of a protective Cr-nitride surface by gas nitridation, at a sufficiently low cost to meet DOE targets and with sufficient ductility to permit manufacture by stamping. (2) Demonstrate capability of nitridation to yield high-quality stainless steel bipolar plates from thin stamped alloy foils (no significant stamped foil warping or embrittlement). (3) Demonstrate single-cell fuel cell performance of stamped and nitrided alloy foils equivalent to that of machined graphite plates of the same flow-field design ({approx}750-1,000 h, cyclic conditions, to include quantification of metal ion contamination of the membrane electrode assembly [MEA] and contact resistance increase attributable to the bipolar plates). (4) Demonstrate potential for adoption in automotive fuel cell stacks. Thin stamped metallic bipolar plates offer the potential for (1) significantly lower cost than currently-used machined graphite bipolar plates, (2) reduced weight/volume, and (3) better performance and amenability to high volume manufacture than developmental polymer/carbon fiber and graphite composite bipolar plates. However, most metals exhibit inadequate corrosion resistance in proton exchange membrane fuel cell (PEMFC) environments. This behavior leads to high electrical resistance due to the formation of surface oxides and/or contamination of the MEA by metallic ions, both of which can significantly degrade fuel cell performance. Metal nitrides offer electrical conductivities up to an order of magnitude greater than that of graphite and are highly corrosion resistant. Unfortunately, most conventional coating methods (for metal nitrides) are too expensive for PEMFC stack commercialization or tend to leave pinhole defects, which result in accelerated local corrosion and unacceptable performance.

Brady, Michael P [ORNL; Tortorelli, Peter F [ORNL; Pihl, Josh A [ORNL; Toops, Todd J [ORNL; More, Karren Leslie [ORNL; Meyer III, Harry M [ORNL; Vitek, John Michael [ORNL; Wang, Heli [National Renewable Energy Laboratory (NREL); Turner, John [National Renewable Energy Laboratory (NREL); Wilson, Mahlon [Los Alamos National Laboratory (LANL); Garzon, Fernando [Los Alamos National Laboratory (LANL); Rockward, Tommy [Los Alamos National Laboratory (LANL); Connors, Dan [GenCell Corp; Rakowski, Jim [Allegheny Ludlum; Gervasio, Don [Arizona State University

2008-01-01T23:59:59.000Z

50

Cubic nitride templates  

DOE Patents [OSTI]

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.

Burrell, Anthony K; McCleskey, Thomas Mark; Jia, Quanxi; Mueller, Alexander H; Luo, Hongmei

2013-04-30T23:59:59.000Z

51

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

SciTech Connect (OSTI)

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

David, Aurelien

2012-10-15T23:59:59.000Z

52

GALLIUM--2000 30.1 By Deborah A. Kramer  

E-Print Network [OSTI]

the largest application for gallium, with optoelectronic devices [mostly laser diodes and light-use application for gallium, with 63% of total consumption. Optoelectronic devices accounted for 32% of domestic% of the gallium consumed in the United States was in the form of GaAs. GaAs was manufactured into optoelectronic

53

GALLIUM--1998 29.1 By Deborah A. Kramer  

E-Print Network [OSTI]

's) were the largest application for gallium, with optoelectronic devices [mostly laser diodes and light-use application for gallium, with 52% of total consumption. Optoelectronic devices accounted for 45% of domestic% of the gallium consumed in the United States was in the form of GaAs. GaAs was manufactured into optoelectronic

54

GALLIUM--1999 29.1 By Deborah A. Kramer  

E-Print Network [OSTI]

circuits (IC's) were the largest application for gallium, with optoelectronic devices [mostly laser diodes-use application for gallium, with 52% of total consumption. Optoelectronic devices accounted for 42% of domestic% of the gallium consumed in the United States was in the form of GaAs. GaAs was manufactured into optoelectronic

55

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.

56

Superplastic forging nitride ceramics  

DOE Patents [OSTI]

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.

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

1988-03-22T23:59:59.000Z

57

Characterization of nitrided silicon-silicon dioxide interfaces  

SciTech Connect (OSTI)

A newly-developed technique for the simultaneous characterization of the oxide-silicon interface properties and of bulk impurities was used for a systematic study of the nitridation process of thin oxides. This technique is based upon surface recombination velocity measurements, and does not require the formation of a capacitor structure, so it is very suitable for the characterization of as-grown interfaces. Oxides grown both in dry and in wet environments were considered, and nitridation processes in N{sub 2}O and in NO were compared to N{sub 2} annealing processes. The effect of nitridation temperature and duration were also studied, and RTO/RTN processes were compared to conventional furnace nitridation processes. Surface recombination velocity was correlated with nitrogen concentration at the oxide-silicon interface obtained by Secondary Ion Mass Spectroscopy (SIMS) measurements. Surface recombination velocity (hence surface state density) decreases with increasing nitrogen pile-up at the oxide-silicon interface, indicating that in nitrided interfaces surface state density is limited by nitridation. NO treatments are much more effective than N{sub 2}O treatments in the formation of nitrogen-rich interface layer and, as a consequence, in surface state reduction. Surface state density was measured in fully processed wafers before and after constant current stress. After a complete device process surface states are annealed out by hydrogen passivation, however they are reactivated by the electrical stress, and surface state results after stress were compared with data of surface recombination velocity in as-processed wafers.

Polignano, M.L.; Alessandri, M.; Brazzelli, D. [and others

2000-07-01T23:59:59.000Z

58

Silicon nitride ceramic comprising samaria and ytterbia  

DOE Patents [OSTI]

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

Yeckley, Russell L. (Oakham, MA)

1996-01-01T23:59:59.000Z

59

Process for preparing a densified beta-phase silicon nitride material having at least one densification aid, and the material resulting therefrom  

SciTech Connect (OSTI)

A process is described for preparing an alpha-phase silicon nitride material and thereafter sintering to a densified beta-phase silicon nitride material, comprising: (a) comminuting a slurry including a mixture of (i) silicon-containing powder, (ii) water, and (iii) at least one densification aid to aid in later densifying of the silicon nitride material, said comminuting being performed to form fresh, non-oxidized surfaces on the silicon powder and to allow substantial chemical reaction between the silicon and the water, said comminuting being performed to form fresh, non-oxidized surfaces on the silicon powder and to allow substantial chemical reaction between the silicon and the water, yielding a mass; (b) nitriding the mass by exposure to a sufficient amount of a nitriding gas including at least nitrogen at a sufficient temperature for a sufficient length of time to form a mass of substantially alpha-phase silicon nitride; and (c) sintering the resultant silicon nitride mass at a sintering holding temperature of from about 1,450 C to about 2,100 C for a sufficient length of time to convert the silicon nitride from a predominantly alpha-phase material to a predominantly densified beta phase silicon nitride material exhibiting a decrease in bulk volume of the silicon nitride due to the densification.

Edler, J.P.; Lisowsky, B.

1993-05-25T23:59:59.000Z

60

Functionalized boron nitride nanotubes  

DOE Patents [OSTI]

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.

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

2014-04-22T23:59:59.000Z

Note: This page contains sample records for the topic "bulk gallium nitride" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

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

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

(nanowires) in the compound gallium selenide. In short, ordered lines of structural vacancies in the material stimulate the growth of "one-dimensional" structures less than 1...

62

Study of nitrogen-rich titanium and zirconium nitride films  

SciTech Connect (OSTI)

Thin titanium nitride (TiN) and zirconium nitride (ZrN) films containing excess nitrogen up to 59 and 63 at. % N, respectively, were deposited on austenitic stainless-steel substrates by reactive triode ion plating at about 823 K. The film structure and surface chemistry were studied using x-ray diffraction, scanning Auger spectroscopy, and electron energy-loss spectroscopy (EELS). In TiN films only the face-centered-cubic mononitride phase was detected. The lattice parameter of the stoichiometric TiN film was larger than the corresponding bulk value and it increased with increasing nitrogen content. The lattice parameter of overstoichiometric ZrN films showed abnormal behavior when calculated from different diffracting planes. This behavior together with the EELS and other measurements indicate that a dielectric Zr/sub 3/N/sub 4/ phase was formed at overstoichiometric compositions.

Ristolainen, E.O.; Molarius, J.M.; Korhonen, A.S.; Lindroos, V.K.

1987-07-01T23:59:59.000Z

63

Photonuclear Reaction Cross Sections for Gallium Isotopes  

E-Print Network [OSTI]

The photon induced reactions which are named as photonuclear reactions have a great importance in many field of nuclear, radiation physics and related fields. Since we have planned to perform photonuclear reaction on gallium target with bremmstrahlung photons from clinical linear accelerator in the future, the cross-sections of neutron (photo-neutron ({\\gamma},xn)) and proton (photo-proton ({\\gamma},xn)) productions after photon activation have been calculated by using TALYS 1.2 computer code in this study. The target nucleus has been considered gallium which has two stable isotopes, 69Ga and 71Ga. According to the results, we have seen that the calculations are in harmony in the limited literature values. Furthermore, the pre-equilibrium and compound process contributions to the total cross-section have been investigated.

Serkan Akkoyun; Tuncay Bayram

2014-09-08T23:59:59.000Z

64

Optical Constants ofOptical Constants of Uranium Nitride Thin FilmsUranium Nitride Thin Films  

E-Print Network [OSTI]

Optical Constants ofOptical Constants of Uranium Nitride Thin FilmsUranium Nitride Thin FilmsDelta--Beta Scatter Plot at 220 eVBeta Scatter Plot at 220 eV #12;Why Uranium Nitride?Why Uranium Nitride? UraniumUranium, uranium,Bombard target, uranium, with argon ionswith argon ions Uranium atoms leaveUranium atoms leave

Hart, Gus

65

Standard Reference Material 1751: Gallium Melting-Point Standard  

E-Print Network [OSTI]

Standard Reference Material 1751: Gallium Melting-Point Standard Gregory F. Strouse NIST Special Publication 260-157 #12;#12;NIST Special Publication 260-157 XXXX Standard Reference Material 1751: Gallium Melting-Point Standard Gregory F. Strouse Chemical Science and Technology Laboratory Process Measurements

66

Rotary bulk solids divider  

DOE Patents [OSTI]

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.

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

1992-01-01T23:59:59.000Z

67

Thermal conductivity of ultra-thin chemical vapor deposited hexagonal boron nitride films  

SciTech Connect (OSTI)

Thermal conductivity of freestanding 10?nm and 20?nm thick chemical vapor deposited hexagonal boron nitride films was measured using both steady state and transient techniques. The measured value for both thicknesses, about 100?±?10?W m{sup ?1} K{sup ?1}, is lower than the bulk basal plane value (390?W m{sup ?1} K{sup ?1}) due to the imperfections in the specimen microstructure. Impressively, this value is still 100 times higher than conventional dielectrics. Considering scalability and ease of integration, hexagonal boron nitride grown over large area is an excellent candidate for thermal management in two dimensional materials-based nanoelectronics.

Alam, M. T.; Haque, M. A., E-mail: mah37@psu.edu [Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Bresnehan, M. S.; Robinson, J. A. [Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA and The Center for Two-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)] [Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA and The Center for Two-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

2014-01-06T23:59:59.000Z

68

TiN surface dynamics: role of surface and bulk mass transport processes  

E-Print Network [OSTI]

TiN surface dynamics: role of surface and bulk mass transport processes J. Bareñoa , S. Kodambakab, USA Abstract. Transition-metal nitrides, such as TiN, have a wide variety of applications as hard/decay kinetics of two- and three-dimensional TiN(111) islands and the effect of surface-terminated dislocations

Khare, Sanjay V.

69

Radiation-Hardened Gallium Nitride Detector and Arrays for Fusion Diagnostics  

SciTech Connect (OSTI)

This poster reports testing to confirm that GaN devices exhibit the extreme radiation hardness needed for use at the NIF, functioning properly after 1x10{sup 12} protons/cm{sup 2} proton irradiation in one year.

Sun, K. X., and MacNeil, L.

2011-09-08T23:59:59.000Z

70

The equilibrium state of hydrogen in gallium nitride: Theory and experiment  

SciTech Connect (OSTI)

Formation energies and vibrational frequencies for H in wurtzite GaN were calculated from density functional theory and used to predict equilibrium state occupancies and solid solubilities for p-type, intrinsic, and n-type material. The solubility of deuterium (D) was measured at 600--800 C as a function of D{sub 2} pressure and doping and compared with theory. Agreement was obtained by reducing the H formation energies 0.2 eV from ab-initio theoretical values. The predicted stretch-mode frequency for H bound to the Mg acceptor lies 5% above an observed infrared absorption attributed to this complex. It is concluded that currently recognized H states and physical processes account for the equilibrium behavior of H examined in this work.

MYERS JR.,SAMUEL M.; WRIGHT,ALAN F.; PETERSEN,GARY A.; SEAGER,CARLETON H.; WAMPLER,WILLIAM R.; CRAWFORD,MARY H.; HAN,JUNG

2000-04-17T23:59:59.000Z

71

Diffusion, Uptake and Release of Hydrogen in p-type Gallium Nitride: Theory and Experiment  

SciTech Connect (OSTI)

The diffusion, uptake, and release of H in p-type GaN are modeled employing state energies from density-function theory and compared with measurements of deuterium uptake and release using nuclear-reaction analysis. Good semiquantitative agreement is found when account is taken of a surface permeation barrier.

MYERS JR.,SAMUEL M.; WRIGHT,ALAN F.; PETERSEN,GARY A.; WAMPLER,WILLIAM R.; SEAGER,CARLETON H.; CRAWFORD,MARY H.; HAN,JUNG

2000-06-27T23:59:59.000Z

72

Growth Kinetics and Doping of Gallium Nitride Grown by rf-Plasma Assisted Molecular Beam Epitaxy  

E-Print Network [OSTI]

Thomas H. Myers, Ph.D., Chair Larry E. Halliburton, Ph.D. Nancy C. Giles, Ph.D. Charter D. Stinespring Giles, Dr. Charter Stinespring, Dr. Larry Halliburton, and Dr. Mohindar Seehra. In addition, I would

Myers, Tom

73

Commercialization of gallium nitride nanorod arrays on silicon for solid-state lighting  

E-Print Network [OSTI]

One important component in energy usage is lighting, which is currently dominated by incandescent and fluorescent lamps. However, due to potentially higher efficiencies and thus higher energy savings, solid-state lighting ...

Wee, Qixun

2008-01-01T23:59:59.000Z

74

Effect of Gallium Nitride Template Layer Strain on the Growth of  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed NewcatalystNeutronEnvironmentZIRKLE FRUITYear 1MATERIALSTiO2(110).

75

Silicon nitride/silicon carbide composite powders  

DOE Patents [OSTI]

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.

Dunmead, Stephen D. (Midland, MI); Weimer, Alan W. (Midland, MI); Carroll, Daniel F. (Midland, MI); Eisman, Glenn A. (Midland, MI); Cochran, Gene A. (Midland, MI); Susnitzky, David W. (Midland, MI); Beaman, Donald R. (Midland, MI); Nilsen, Kevin J. (Midland, MI)

1996-06-11T23:59:59.000Z

76

(Data in kilograms of gallium content unless otherwise noted) Domestic Production and Use: No domestic primary (crude, unrefined) gallium was recovered in 2013. Globally,  

E-Print Network [OSTI]

% of the gallium consumed was used in integrated circuits (ICs). Optoelectronic devices, which include laser diodes of the remaining gallium consumption. Optoelectronic devices were used in aerospace applications, consumer goods

77

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

78

Cavity optomechanics in gallium phosphide microdisks  

SciTech Connect (OSTI)

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.

Mitchell, Matthew; Barclay, Paul E., E-mail: pbarclay@ucalgary.ca [Institute for Quantum Science and Technology, University of Calgary, Calgary, Alberta T2N 1N4 (Canada); National Institute for Nanotechnology, 11421 Saskatchewan Dr. NW, Edmonton, Alberta T6G 2M9 (Canada); Hryciw, Aaron C. [National Institute for Nanotechnology, 11421 Saskatchewan Dr. NW, Edmonton, Alberta T6G 2M9 (Canada)

2014-04-07T23:59:59.000Z

79

Large area bulk superconductors  

DOE Patents [OSTI]

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.

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

2002-01-01T23:59:59.000Z

80

amorphous carbon nitride: Topics by E-print Network  

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

Si-rich nitride Er:SRN materials have 3 Carbon Nitride and Conjugated Polymer Composite Materials. Open Access Theses and Dissertations Summary: ??The semiconductor and...

Note: This page contains sample records for the topic "bulk gallium nitride" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Vacancies in fully hydrogenated boron nitride layer: implications...  

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

Vacancies in fully hydrogenated boron nitride layer: implications for functional nanodevices. Vacancies in fully hydrogenated boron nitride layer: implications for functional...

82

Silicon nitride having a high tensile strength  

DOE Patents [OSTI]

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

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)

1998-01-01T23:59:59.000Z

83

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...

84

Application of ultrasound in solvent extraction of nickel and gallium  

SciTech Connect (OSTI)

The effects of ultrasound on the rate of solvent extraction of nickel with Lix 65N and Lix 70, and gallium with Kelex 100 were investigated. These solvent extraction systems are noted by their sluggish nature. Low frequency (20 kHz) ultrasound increased the rates of extraction of nickel by factors of four to seven. The ultrasound had no effect on the final chemical equilibrium. Gallium extraction rates were enhanced with the use of ultrasound by as much as a factor of 15. Again, the ultrasound had no effect on extraction equilibrium. For both nickel and gallium, the enhanced rates were attributed to increased interfacial surface area associated with ultrasonically induced cavitation and microdroplet formation. The stability of the microdroplets permitted intermittent application of ultrasound with corresponding decreases in ultrasonic energy requirements. The lowest energy consumption was observed with short (0.25 to 5 s) bursts of high power (41 to 61 W) ultrasonic inputs. The study also provided insight into the factors that affect the complex extraction of gallium from sodium aluminate solutions. The rate controlling step was found to be the dehydration of the gallate ion, Ga(OH)4, and the first complex formation between gallium and Kelex 100. Sodium was found to enhance the extraction rate up to a point, beyond which increased concentration was detrimental. Increasing aluminum concentration was found to slow extraction rates. Modifiers and diluents were shown to markedly affect extraction rates even without ultrasound. Ketone modifiers, particularly 2-undecanone, when used with Kermac 470B or Escaid 200 diluents enhanced extraction rates of gallium to the point that the use of ultrasound provided no additional benefits. The positive effects of ketone modifiers for the solvent extraction of gallium had not been previously reported.

Pesic, B.

1996-07-01T23:59:59.000Z

85

Gallium based low-interaction anions  

DOE Patents [OSTI]

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.

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

2000-01-01T23:59:59.000Z

86

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

DOE Patents [OSTI]

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.

Hogan, S.J.

1983-03-13T23:59:59.000Z

87

Method of preparation of uranium nitride  

DOE Patents [OSTI]

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.

Kiplinger, Jaqueline Loetsch; Thomson, Robert Kenneth James

2013-07-09T23:59:59.000Z

88

Molten-Salt-Based Growth of Group III Nitrides  

DOE Patents [OSTI]

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.

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

2008-10-14T23:59:59.000Z

89

Bulk Hydrogen Strategic Directions for  

E-Print Network [OSTI]

Bulk Hydrogen Storage Strategic Directions for Hydrogen Delivery Workshop May 7-8, 2003 Crystal City, Virginia #12;Breakout Session - Bulk Hydrogen Storage Main Themes/Caveats Bulk Storage = Anything storage is an economic solution to address supply/demand imbalance #12;Breakout Session - Bulk Hydrogen

90

Aluminum Nitride Micro-Channels Grown via Metal Organic Vapor Phase Epitaxy for MEMs Applications  

SciTech Connect (OSTI)

Aluminum nitride (AlN) is a promising material for a number of applications due to its temperature and chemical stability. Furthermore, AlN maintains its piezoelectric properties at higher temperatures than more commonly used materials, such as Lead Zirconate Titanate (PZT) [1, 2], making AlN attractive for high temperature micro and nanoelectromechanical (MEMs and NEMs) applications including, but not limited to, high temperature sensors and actuators, micro-channels for fuel cell applications, and micromechanical resonators. This work presents a novel AlN micro-channel fabrication technique using Metal Organic Vapor Phase Epitaxy (MOVPE). AlN easily nucleates on dielectric surfaces due to the large sticking coefficient and short diffusion length of the aluminum species resulting in a high quality polycrystalline growth on typical mask materials, such as silicon dioxide and silicon nitride [3,4]. The fabrication process introduced involves partially masking a substrate with a silicon dioxide striped pattern and then growing AlN via MOVPE simultaneously on the dielectric mask and exposed substrate. A buffered oxide etch is then used to remove the underlying silicon dioxide and leave a free standing AlN micro-channel. The width of the channel has been varied from 5 ìm to 110 ìm and the height of the air gap from 130 nm to 800 nm indicating the stability of the structure. Furthermore, this versatile process has been performed on (111) silicon, c-plane sapphire, and gallium nitride epilayers on sapphire substrates. Reflection High Energy Electron Diffraction (RHEED), Atomic Force Microscopy (AFM), and Raman measurements have been taken on channels grown on each substrate and indicate that the substrate is influencing the growth of the AlN micro-channels on the SiO2 sacrificial layer.

Rodak, L.E.; Kuchibhatla, S.; Famouri, P.; Ting, L.; Korakakis, D.

2008-01-01T23:59:59.000Z

91

Compressibilities and phonon spectra of high-hardness transition metal-nitride materials  

SciTech Connect (OSTI)

We report compressibilities measured by synchrotron X-ray diffraction and phonon spectra from Raman scattering at high pressure in the diamond anvil cell (DAC) for cubic transition metal nitrides TiN{sub 1-x}, {gamma}-Mo{sub 2}N and VN{sub x}. The high-hardness metal nitride compounds have large values of the bulk modulus. B1-structured nitrides normally have no allowed first-order Raman spectra. However, they exhibit broad bands that reflect the vibrational density of states g({omega}) associated with breakdown of q=0 selection rules because of the presence of N{sup 3-} vacancies on anion sites. Peaks in g({omega}) at low frequency are identified with the longitudinal and transverse acoustic (TA) branches. The maximum in the TA band is correlated with the superconducting transition temperature in these materials (T{sub c}). In situ Raman scattering measurements in the DAC thus permit predictions of the T{sub c} variation with pressure for cubic nitrides and isostructural carbide materials.

Shebanova, O.; Soignard, E.; Mcmillan, P.F. (ASU); (UCL)

2010-01-20T23:59:59.000Z

92

Interaction of a Liquid Gallium Jet with ISTTOK Edge Plasmas  

SciTech Connect (OSTI)

The use of liquid metals as plasma facing components in tokamaks has recently experienced a renewed interest stimulated by their advantages in the development of a fusion reactor. Liquid metals have been proposed to solve problems related to the erosion and neutronic activation of solid walls submitted to high power loads allowing an efficient heat exhaust from fusion devices. Presently the most promising candidate materials are lithium and gallium. However, lithium has a short liquid state range when compared, for example, with gallium that has essentially better thermal properties and lower vapor pressure. To explore further these properties, ISTTOK tokamak is being used to test the interaction of a free flying, fully formed liquid gallium jet with the plasma. The interacting, 2.3 mm diameter, jet is generated by hydrostatic pressure and has a 2.5 m/s flow velocity. The liquid metal injector has been build to allow the positioning of the jet inside the tokamak chamber, within a 13 mm range. This paper presents the first obtained experimental results concerning the liquid gallium jet-plasma interaction. A stable jet has been obtained, which was not noticeably affected by the magnetic field transients. ISTTOK has been successfully operated with the gallium jet without degradation of the discharge or a significant plasma contamination by liquid metal. This observation is supported by spectroscopic measurements showing that gallium radiation is limited to the region around the jet. Furthermore, the power deposited on the jet has been evaluated at different radial locations and the surface temperature increase estimated.

Gomes, R. B.; Fernandes, H.; Silva, C.; Pereira, T.; Figueiredo, J.; Carvalho, B.; Soares, A.; Duarte, P.; Varandas, C. [Associacao EURATOM/IST, Centro de Fusao Nuclear, Av. Rovisco Pais, 1049-001 Lisboa, Porugal (Portugal); Sarakovskis, A.; Lielausis, O.; Klyukin, A.; Platacis, E.; Tale, I. [Association EURATOM/University of Latvia, Institute of Solid State Physics, 8 Kengaraga Str., LV-1063 Riga (Latvia)

2008-04-07T23:59:59.000Z

93

Synthesis of transition metal nitride by nitridation of metastable oxide precursor  

SciTech Connect (OSTI)

Metastable transition metal oxides were used as precursors to synthesize transition metal nitrides at low temperature. Amorphous MoO{sub 2} was prepared by reduction of (NH{sub 4}){sub 6}Mo{sub 7}O{sub 24} solution with hydrazine. As-synthesized amorphous MoO{sub 2} was transformed into fcc {gamma}-Mo{sub 2}N at 400 Degree-Sign C and then into hexagonal {delta}-MoN by further increasing the temperature to 600 Degree-Sign C under a NH{sub 3} flow. The nitridation temperature employed here is much lower than that employed in nitridation of crystalline materials, and the amorphous materials underwent a unique nitridation process. Besides this, the bimetallic nitride Ni{sub 2}Mo{sub 3}N was also synthesized by nitridating amorphous bimetallic precursor. These results suggested that the nitridation of amorphous precursor possessed potential to be a general method for synthesizing many interstitial metallic compounds, such as nitrides and carbides at low temperature. - graphical abstract: Amorphous oxide was used as new precursor to prepare nitride at low temperature. Pure {gamma}-Mo{sub 2}N and {delta}-MoN were obtained at 400 Degree-Sign C and at 600 Degree-Sign C, respectively. Highlights: Black-Right-Pointing-Pointer We bring out a new method to synthesize transition metal nitrides at low temperature. Black-Right-Pointing-Pointer Both mono- and bimetallic molybdenum nitrides were synthesized at a mild condition. Black-Right-Pointing-Pointer The formation of two different molybdenum nitrides {gamma}-Mo{sub 2}N and {delta}-MoN can be controlled from the same metastable precursor. Black-Right-Pointing-Pointer The nitridation temperature was much lower than that reported from crystalline precursors. Black-Right-Pointing-Pointer The metastable precursor had different reaction process in comparison with crystalline precursor.

Wang, Huamin; Wu, Zijie; Kong, Jing [Key Laboratory of Advanced Energy Materials Chemistry (MOE), College of Chemistry, Nankai University, Tianjin 300071 (China)] [Key Laboratory of Advanced Energy Materials Chemistry (MOE), College of Chemistry, Nankai University, Tianjin 300071 (China); Wang, Zhiqiang, E-mail: zqwang@mail.nankai.edu.cn [Key Laboratory of Advanced Energy Materials Chemistry (MOE), College of Chemistry, Nankai University, Tianjin 300071 (China) [Key Laboratory of Advanced Energy Materials Chemistry (MOE), College of Chemistry, Nankai University, Tianjin 300071 (China); Tianjin Key Laboratory of Water Environment and Resources, Tianjin Normal University, No. 393 Binshui Road, Xiqing Dist., Tianjin 300387 (China); Zhang, Minghui, E-mail: zhangmh@nankai.edu.cn [Key Laboratory of Advanced Energy Materials Chemistry (MOE), College of Chemistry, Nankai University, Tianjin 300071 (China)] [Key Laboratory of Advanced Energy Materials Chemistry (MOE), College of Chemistry, Nankai University, Tianjin 300071 (China)

2012-10-15T23:59:59.000Z

94

GALLIUM--1997 29.1 By Deborah A. Kramer  

E-Print Network [OSTI]

As is manufactured into optoelectronic devices (LED's, laser diodes, photodetectors, and solar cells) and integrated consumption. Optoelectronic devices accounted for 44% of domestic consumption, and the remaining 7% was used by imports, primarily high-purity gallium from France and low-purity material from Russia. Optoelectronic

95

Bulk Power Transmission Study  

E-Print Network [OSTI]

BULK POWER TRANSMISSION STUDY TOMMY JOH~ P. E. Manager of Resource Recovery Waste Management of North America, Inc. Houston, Texas Texans now have a choice. We can become more efficient and maintain our standard of living, or we can... continue business as usual and watch our standard of living erode from competition from other regions. In the past, except for improving reliability, there was no need for a strong transmission system. When Texas generation was primarily gas fueled...

John, T.

96

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

SciTech Connect (OSTI)

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.

Petravic, Mladen; Peter, Robert; Varasanec, Marijana [Department of Physics and Center for Micro and Nano Sciences and Technologies, University of Rijeka, 51000 Rijeka (Croatia); Li Luhua; Chen Ying [Institute for Technology Research and Innovation, Deakin University, Geelong Waurn Ponds Campus, 3217 (Australia); Cowie, Bruce C. C. [Australian Synchrotron, Clayton VIC 3168 (Australia)

2013-05-15T23:59:59.000Z

97

Self- and zinc diffusion in gallium antimonide  

SciTech Connect (OSTI)

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.

Nicols, Samuel Piers

2002-03-26T23:59:59.000Z

98

Sputtering of tin and gallium-tin clusters  

SciTech Connect (OSTI)

Tin and gallium-tin clusters have been produced by 4 keV Ar{sup +} ion bombardment of polycrystalline tin and the gallium-tin eutectic alloy and analyzed by time-of-flight mass spectrometry. The sputtered neutral species were photoionized with 193 nm (6.4 eV) excimer laser light. Neutral tin clusters containing up to 10 atoms and mixed gallium-tin clusters Ga{sub (n-m)}Sn{sub m} with n {<=} 4 for the neutrals and N {<=} 3 for the sputtered ionic species have been detected. Laser power density dependent intensity measurements, relative yields, and kinetic energy distributions have been measured. The abundance distributions of the mixed clusters have been found to be nonstatistical due to significant differences in the ionization efficiencies for clusters with equal nuclearity but different number of tin atoms. The results indicate that Ga{sub 2}Sn and Ga{sub 3}Sn like the all-gallium clusters have ionization potentials below 6.4 eV. In the case of Sn{sub 5}, Sn{sub 6}, GaSn and Ga{sub (n-m)}Sn{sub m} clusters with n=2 to 4 and m>1, the authors detect species that have sufficient internal energy to be one photon ionized despite ionization potentials that are higher 6.4 eV. The tin atom signal that is detected can be attributed to photofragmentation of dimers for both sputtering from polycrystalline tin and from the gallium-tin eutectic alloy.

Lill, T.; Calaway, W.F.; Ma, Z.; Pellin, M.J.

1994-08-01T23:59:59.000Z

99

Method of nitriding refractory metal articles  

DOE Patents [OSTI]

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.

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)

1994-01-01T23:59:59.000Z

100

Method of nitriding refractory metal articles  

DOE Patents [OSTI]

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.

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

1994-03-15T23:59:59.000Z

Note: This page contains sample records for the topic "bulk gallium nitride" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Low temperature route to uranium nitride  

DOE Patents [OSTI]

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.

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)

2009-09-01T23:59:59.000Z

102

The Nitrogen-Nitride Anode.  

SciTech Connect (OSTI)

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.

Delnick, Frank M.

2014-10-01T23:59:59.000Z

103

Surface reactivity and oxygen migration in amorphous indium-gallium-zinc oxide films annealed in humid atmosphere  

SciTech Connect (OSTI)

An isotope tracer study, i.e., {sup 18}O/{sup 16}O exchange using {sup 18}O{sub 2} and H{sub 2}{sup 18}O, was performed to determine how post-deposition annealing (PDA) affected surface reactivity and oxygen diffusivity of amorphous indium–gallium–zinc oxide (a-IGZO) films. The oxygen tracer diffusivity was very high in the bulk even at low temperatures, e.g., 200?°C, regardless of PDA and exchange conditions. In contrast, the isotope exchange rate, dominated by surface reactivity, was much lower for {sup 18}O{sub 2} than for H{sub 2}{sup 18}O. PDA in a humid atmosphere at 400?°C further suppressed the reactivity of O{sub 2} at the a-IGZO film surface, which is attributable to –OH-terminated surface formation.

Watanabe, Ken, E-mail: Watanabe.Ken@nims.go.jp [International Center for Young Scientists (ICYS-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044 (Japan)] [International Center for Young Scientists (ICYS-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044 (Japan); Lee, Dong-Hee [Optical and Electronic Materials Unit, NIMS, 1-1 Namiki, Tsukuba 305-0044 (Japan) [Optical and Electronic Materials Unit, NIMS, 1-1 Namiki, Tsukuba 305-0044 (Japan); Materials and Structures Laboratory (MSL), Tokyo Institute of Technology, Mailbox R3-4, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan); Sakaguchi, Isao; Haneda, Hajime [Optical and Electronic Materials Unit, NIMS, 1-1 Namiki, Tsukuba 305-0044 (Japan)] [Optical and Electronic Materials Unit, NIMS, 1-1 Namiki, Tsukuba 305-0044 (Japan); Nomura, Kenji [Frontier Research Center, Tokyo Institute of Technology, Mailbox S2-13, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan)] [Frontier Research Center, Tokyo Institute of Technology, Mailbox S2-13, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan); Kamiya, Toshio [Materials and Structures Laboratory (MSL), Tokyo Institute of Technology, Mailbox R3-4, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan) [Materials and Structures Laboratory (MSL), Tokyo Institute of Technology, Mailbox R3-4, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan); Materials Research Center for Element Strategy (MCES), Mailbox S2-13, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan); Hosono, Hideo [Materials and Structures Laboratory (MSL), Tokyo Institute of Technology, Mailbox R3-4, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan) [Materials and Structures Laboratory (MSL), Tokyo Institute of Technology, Mailbox R3-4, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan); Frontier Research Center, Tokyo Institute of Technology, Mailbox S2-13, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan); Materials Research Center for Element Strategy (MCES), Mailbox S2-13, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan); Ohashi, Naoki, E-mail: Ohashi.Naoki@nims.go.jp [Optical and Electronic Materials Unit, NIMS, 1-1 Namiki, Tsukuba 305-0044 (Japan) [Optical and Electronic Materials Unit, NIMS, 1-1 Namiki, Tsukuba 305-0044 (Japan); Materials Research Center for Element Strategy (MCES), Mailbox S2-13, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-0026 (Japan)

2013-11-11T23:59:59.000Z

104

European Photovoltaic Solar Energy Conference, Valencia, Spain, 6-10 September 2010, 2DO.1.6 BULK LIFETIME ENHANCEMENT BY FIRING STEPS  

E-Print Network [OSTI]

25th European Photovoltaic Solar Energy Conference, Valencia, Spain, 6-10 September 2010, 2DO.1.6 1 to getter metallic impurities and firing of silicon nitride (SiN) to induce hydrogen passivation. We analyse impurities and hydrogen bulk passivation, respectively. Additionally, the fired SiN layers have to ensure

105

Superconductive silicon nanowires using gallium beam lithography.  

SciTech Connect (OSTI)

This work was an early career LDRD investigating the idea of using a focused ion beam (FIB) to implant Ga into silicon to create embedded nanowires and/or fully suspended nanowires. The embedded Ga nanowires demonstrated electrical resistivity of 5 m-cm, conductivity down to 4 K, and acts as an Ohmic silicon contact. The suspended nanowires achieved dimensions down to 20 nm x 30 nm x 10 m with large sensitivity to pressure. These structures then performed well as Pirani gauges. Sputtered niobium was also developed in this research for use as a superconductive coating on the nanowire. Oxidation characteristics of Nb were detailed and a technique to place the Nb under tensile stress resulted in the Nb resisting bulk atmospheric oxidation for up to years.

Henry, Michael David; Jarecki, Robert Leo,

2014-01-01T23:59:59.000Z

106

Method of manufacture of atomically thin boron nitride  

DOE Patents [OSTI]

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.

Zettl, Alexander K

2013-08-06T23:59:59.000Z

107

E-Print Network 3.0 - arsenide- gallium instrument Sample Search...  

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

Summary: of gallium arsenide, a semiconductor, which is used in advanced optoelectronics, lasers, microwave circuits... , and solar cells. To determine material...

108

E-Print Network 3.0 - aluminum gallium indium Sample Search Results  

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

Physics, Portland State University Collection: Physics 2 Alternative Energy Technologies Solar Power Summary: CIGS - Copper - Indium - Gallium - diSelenide Cd-Te -- Cadmium...

109

Preparation Of Copper Indium Gallium Diselenide Films For Solar Cells  

DOE Patents [OSTI]

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.

Bhattacharya, Raghu N. (Littleton, CO); Contreras, Miguel A. (Golden, CO); Keane, James (Lakewood, CO); Tennant, Andrew L. (Denver, CO), Tuttle, John R. (Denver, CO); Ramanathan, Kannan (Lakewood, CO); Noufi, Rommel (Golden, CO)

1998-08-08T23:59:59.000Z

110

Creating bulk nanocrystalline metal.  

SciTech Connect (OSTI)

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.

Fredenburg, D. Anthony (Georgia Institute of Technology, Atlanta, GA); Saldana, Christopher J. (Purdue University, West Lafayette, IN); Gill, David D.; Hall, Aaron Christopher; Roemer, Timothy John (Ktech Corporation, Albuquerque, NM); Vogler, Tracy John; Yang, Pin

2008-10-01T23:59:59.000Z

111

Silicon nitride ceramic having high fatigue life and high toughness  

DOE Patents [OSTI]

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.

Yeckley, Russell L. (Oakham, MA)

1996-01-01T23:59:59.000Z

112

Evaluation of silicon-nitride ceramic valves.  

SciTech Connect (OSTI)

Silicon-nitride ceramic valves can improve the performance of both light- and heavy-duty automotive engines because of the superior material properties of silicon nitrides over current metal alloys. However, ceramics are brittle materials that may introduce uncertainties in the reliability and durability of ceramic valves. As a result, the lifetime of ceramic valves are difficult to predict theoretically due to wide variations in the type and distribution of microstructural flaws in the material. Nondestructive evaluation (NDE) methods are therefore required to assess the quality and reliability of these valves. Because ceramic materials are optically translucent and the strength-limiting flaws are normally located near the valve surface, a laser-scatter method can be used for NDE evaluation of ceramic valves. This paper reviews the progress in the development of this NDE method and its application to inspect silicon-nitride ceramic valves at various stages of manufacturing and bench and engine tests.

Sun, J. G.; Zhang, J. M.; Andrews, M. J.; Tretheway, J. S.; Phillips, N. S .L.; Jensen, J. A.; Nuclear Engineering Division; Univ. of Texas; Caterpillar, Inc.

2008-01-01T23:59:59.000Z

113

Comparative band alignment of plasma-enhanced atomic layer deposited high-k dielectrics on gallium nitride  

SciTech Connect (OSTI)

Al{sub 2}O{sub 3} films, HfO{sub 2} films, and HfO{sub 2}/Al{sub 2}O{sub 3} stacked structures were deposited on n-type, Ga-face, GaN wafers using plasma-enhanced atomic layer deposition (PEALD). The wafers were first treated with a wet-chemical clean to remove organics and an in-situ combined H{sub 2}/N{sub 2} plasma at 650 Degree-Sign C to remove residual carbon contamination, resulting in a clean, oxygen-terminated surface. This cleaning process produced slightly upward band bending of 0.1 eV. Additional 650 Degree-Sign C annealing after plasma cleaning increased the upward band bending by 0.2 eV. After the initial clean, high-k oxide films were deposited using oxygen PEALD at 140 Degree-Sign C. The valence band and conduction band offsets (VBOs and CBOs) of the Al{sub 2}O{sub 3}/GaN and HfO{sub 2}/GaN structures were deduced from in-situ x-ray and ultraviolet photoemission spectroscopy (XPS and UPS). The valence band offsets were determined to be 1.8 and 1.4 eV, while the deduced conduction band offsets were 1.3 and 1.0 eV, respectively. These values are compared with the theoretical calculations based on the electron affinity model and charge neutrality level model. Moreover, subsequent annealing had little effect on these offsets; however, the GaN band bending did change depending on the annealing and processing. An Al{sub 2}O{sub 3} layer was investigated as an interfacial passivation layer (IPL), which, as results suggest, may lead to improved stability, performance, and reliability of HfO{sub 2}/IPL/GaN structures. The VBOs were {approx}0.1 and 1.3 eV, while the deduced CBOs were 0.6 and 1.1 eV for HfO{sub 2} with respect to Al{sub 2}O{sub 3} and GaN, respectively.

Yang Jialing; Eller, Brianna S.; Zhu Chiyu; England, Chris; Nemanich, Robert J. [Department of Physics, Arizona State University, Tempe, Arizona 85287-1504 (United States)

2012-09-01T23:59:59.000Z

114

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

SciTech Connect (OSTI)

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.

STEVE SEDLOCK

2012-04-04T23:59:59.000Z

115

GALLIUM NITRIDE INTEGRATED GAS/TEMPERATURE SENSORS FOR FUEL CELL SYSTEM MONITORING FOR HYDROGEN AND CARBON MONOXIDE  

E-Print Network [OSTI]

on field effect devices using catalytic metal gates on silicon carbide substrates has been reviewed (Spetz-10%) of transition metals such as copper, silver, and chromium (Feinstein et al 1997 and Pyke 1993). High temperature. Introduction Gas sensing and analysis based on gas adsorption on a catalytic metal surface has been extensively

116

Physics based analytical modelling of Gallium Nitride(GaN) MESFET considering different ion implantation energy with high temperature annealing.  

E-Print Network [OSTI]

??A physics based analytical model of ion implanted GaN MESFET has been presented considering high temperature annealing effects. Choosing appropriate activation energy of impurity atoms,… (more)

Raghavan, Vinay

2015-01-01T23:59:59.000Z

117

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

SciTech Connect (OSTI)

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.

Yang, Tsung-Jui; Wu, Yuh-Renn, E-mail: yrwu@ntu.edu.tw [Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Shivaraman, Ravi; Speck, James S. [Department of Materials, University of California, Santa Barbara, California 93106 (United States)

2014-09-21T23:59:59.000Z

118

Nitride Fuel Development at the INL  

SciTech Connect (OSTI)

A new method for fabricating nitride-based fuels for nuclear applications is under development at the Idaho National Laboratory (INL). A primary objective of this research is the development of a process that could be operated as an automated or semi-automated technique reducing costs, worker doses, and eventually improving the final product form. To achieve these goals the fabrication process utilizes a new cryo-forming technique to produce microspheres formed from sub-micron oxide powder to improve material handling issues, yield rapid kinetics for conversion to nitrides, and reduced material impurity levels within the nitride compounds. The microspheres are converted to a nitride form within a high temperature particle fluidizing bed using a carbothermic process that utilizes a hydrocarbon – hydrogen - nitrogen gas mixture. A new monitor and control system using differential pressure changes in the fluidizing gas allows for real-time monitoring and control of the spouted bed reactor during conversion. This monitor and control system can provide real-time data that is used to control the gas flow rates, temperatures, and gas composition to optimize the fluidization of the particle bed. The small size (0.5 µm) of the oxide powders in the microspheres dramatically increases the kinetics of the conversion process yielding reduced process times and temperatures. Initial studies using surrogate ZrO2 powder have yielded conversion efficiencies of 90 -95 % nitride formation with only small levels of oxide and carbide contaminants present. Further studies are being conducted to determine optimal gas mixture ratios, process time, and temperature range for providing complete conversion to a nitride form.

W.E. Windes

2007-06-01T23:59:59.000Z

119

Diffusion of indium and gallium in Cu(In,Ga)Se2 thin film solar cells  

E-Print Network [OSTI]

Diffusion of indium and gallium in Cu(In,Ga)Se2 thin film solar cells O. Lundberga,*, J. Lua , A. Rockettb , M. Edoffa , L. Stolta a A°ngstro¨m Solar Center, Uppsala University, P.O. Box 534, SE-751 21 Abstract The diffusion of indium and gallium in polycrystalline thin film Cu(In,Ga)Se2 layers has been

Rockett, Angus

120

Two-photon photovoltaic effect in gallium arsenide Jeff Chiles,1  

E-Print Network [OSTI]

Two-photon photovoltaic effect in gallium arsenide Jichi Ma,1 Jeff Chiles,1 Yagya D. Sharma,2 214669); published September 4, 2014 The two-photon photovoltaic effect is demonstrated in gallium; (230.0250) Optoelectronics; (040.5350) Photovoltaic; (130.4310) Nonlinear. http://dx.doi.org/10.1364/OL

Fathpour, Sasan

Note: This page contains sample records for the topic "bulk gallium nitride" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Gallium/aluminum nanocomposite material for nonlinear optics and nonlinear plasmonics  

E-Print Network [OSTI]

Gallium/aluminum nanocomposite material for nonlinear optics and nonlinear plasmonics A. V penetration of gallium into an aluminum film. These composite films form mirrorlike interfaces with silica optics and active plasmonics. The material is a polycrystalline aluminum film on a silica sub- strate

Zheludev, Nikolay

122

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

DOE Patents [OSTI]

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.

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

2000-01-01T23:59:59.000Z

123

IEEE JOURNAL OF PHOTOVOLTAICS, VOL. 2, NO. 2, APRIL 2012 123 Gallium Arsenide Solar Cell Absorption  

E-Print Network [OSTI]

IEEE JOURNAL OF PHOTOVOLTAICS, VOL. 2, NO. 2, APRIL 2012 123 Gallium Arsenide Solar Cell Absorption--Gallium arsenide, nanospheres, photovoltaic systems, whispering gallery modes (WGMs). I. INTRODUCTION THE route as the active layer is thinned [2]. Thin-film photovoltaics offer the possibility to significantly reduce

Grandidier, Jonathan

124

Hort-Range Wetting at Liquid Gallium-Bismuth Alloy Surfaces: X-ray Measurements and Square-Gradient Theory  

SciTech Connect (OSTI)

We present an x-ray reflectivity study of wetting at the free surface of the binary liquid metal alloy gallium-bismuth (Ga-Bi) in the region where the bulk phase separates into Bi-rich and Ga-rich liquid phases. The measurements reveal the evolution of the microscopic structure of the wetting films of the Bi-rich, low-surface-tension phase along several paths in the bulk phase diagram. The wetting of the Ga-rich bulk's surface by a Bi-rich wetting film, the thickness of which is limited by gravity to only 50 Angstroms, creates a Ga-rich/Bi-rich liquid/liquid interface close enough to the free surface to allow its detailed study by x rays. The structure of the interface is determined with Angstromsngstrem resolution, which allows the application of a mean-field square gradient model extended by the inclusion of capillary waves as the dominant thermal fluctuations. The sole free parameter of the gradient model, the influence parameter K, that characterizes the influence of concentration gradients on the interfacial excess energy, is determined from our measurements. This, in turn, allows a calculation of the liquid/liquid interfacial tension, and a separation of the intrinsic and capillary wave contributions to the interfacial structure. In spite of expected deviations from MF behavior, based on the upper critical dimensionality (Du = 3 ) of the bulk, we find that the capillary wave excitations only marginally affect the short-range complete wetting behavior. A critical wetting transition that is sensitive to thermal fluctuations appears to be absent in this binary liquid-metal alloy.

Huber, P.; Shpyrko, O; Pershan, P; Ocko, B; DiMasi, E; Deutsch, M

2009-01-01T23:59:59.000Z

125

Anisotropic Hexagonal Boron Nitride Nanomaterials - Synthesis and Applications  

SciTech Connect (OSTI)

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].

Han,W.Q.

2008-08-01T23:59:59.000Z

126

High-Efficiency Nitride-Based Solid-State Lighting  

SciTech Connect (OSTI)

In this final technical progress report we summarize research accomplished during Department of Energy contract DE-FC26-01NT41203, entitled ''High-Efficiency Nitride-Based Solid-State Lighting''. Two teams, from the University of California at Santa Barbara (Principle Investigator: Dr. Shuji Nakamura) and the Lighting Research Center at Rensselaer Polytechnic Institute (led by Dr. N. Narendran), pursued the goals of this contract from thin film growth, characterization, and packaging/luminaire design standpoints. The UCSB team initially pursued the development of blue gallium nitride (GaN)-based vertical-cavity surface-emitting lasers, as well as ultraviolet GaN-based light emitting diodes (LEDs). In Year 2, the emphasis shifted to resonant-cavity light emitting diodes, also known as micro-cavity LEDs when extremely thin device cavities are fabricated. These devices have very directional emission and higher light extraction efficiency than conventional LEDs. Via the optimization of thin-film growth and refinement of device processing, we decreased the total cavity thickness to less than 1 {micro}m, such that micro-cavity effects were clearly observed and a light extraction efficiency of over 10% was reached. We also began the development of photonic crystals for increased light extraction, in particular for so-called ''guided modes'' which would otherwise propagate laterally in the device and be re-absorbed. Finally, we pursued the growth of smooth, high-quality nonpolar a-plane and m-plane GaN films, as well as blue light emitting diodes on these novel films. Initial nonpolar LEDs showed the expected behavior of negligible peak wavelength shift with increasing drive current. M-plane LEDs in particular show promise, as unpackaged devices had unsaturated optical output power of {approx} 3 mW at 200 mA drive current. The LRC's tasks were aimed at developing the subcomponents necessary for packaging UCSB's light emitting diodes, and packaging them to produce a white light fixture. During the third and final year of the project, the LRC team investigated alternate packaging methods for the white LED device to achieve at least 25 percent more luminous efficacy than traditional white LEDs; conducted optical ray-tracing analyses and human factors studies to determine the best form factor for the white light source under development, in terms of high luminous efficacy and greater acceptance by subjects; and developed a new die encapsulant using silicone-epoxy resins that showed less yellowing and slower degradation. At the conclusion of this project, the LRC demonstrated a new packaging method, called scattered photon extraction (SPE), that produced an average luminous flux and corresponding average efficacy of 90.7 lm and 36.3 lm/W, respectively, compared with 56.5 lm and 22.6 lm/W for a similar commercial white LED package. At low currents, the SPE package emitted white light with an efficacy of over 80 lm/W and had chromaticity values very close to the blackbody locus. The SPE package showed an overall improvement of 61% for this particular comparison, exceeding the LRC's third-year goal of 25% improvement.

Paul T. Fini; Shuji Nakamura

2005-07-30T23:59:59.000Z

127

Titanium nitride electrodes for thermoelectric generators  

DOE Patents [OSTI]

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.

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

1987-12-22T23:59:59.000Z

128

Silicon nitride having a high tensile strength  

DOE Patents [OSTI]

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.

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)

1996-01-01T23:59:59.000Z

129

Photodetectors using III-V nitrides  

DOE Patents [OSTI]

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.

Moustakas, Theodore D. (Dover, MA)

1998-01-01T23:59:59.000Z

130

Nitride-bonded silicon carbide composite filter  

SciTech Connect (OSTI)

The objective of this program is to develop and demonstrate an advanced hot gas filter, using ceramic component technology, with enhanced durability to provide increased resistance to thermal fatigue and crack propagation. The material is silicon carbide fiber reinforced nitride bonded silicon carbide.

Thomson, B.N.; DiPietro, S.G.

1995-12-01T23:59:59.000Z

131

Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear SecurityTensile Strain Switched Ferromagnetism inS-4500II FieldVacancy-Induced Nanoscale Wire Structure in Gallium

132

Gallium phosphide high-temperature bipolar junction transistor  

SciTech Connect (OSTI)

Preliminary results are reported on the development of a high-temperature (> 350/sup 0/C) gallium phosphide bipolar junction transistor (BJT) for goethermal and other energy applications. This four-layer p/sup +/n/sup -/pp/sup +/ structure was fromed by liquid phase epitaxy using a supercooling technique to insure uniform nucleation of the thin layers. Magnesium was used as the p-type dopant to avoid excessive out-diffusion into the lightly doped base. By appropriate choice of electrodes, the device may also be driven as an n-channel junction field-effect transistor. The gallium phosphide BJT is observed to have a common-emitter current gain peaking in the range of 6 to 10 (for temperatures from 20/sup 0/C to 400/sup 0/C) and a room-temperature, punchthrough-limited, collector-emitter breakdown voltage of approximately -6V. Other parameters of interest include an f/sub/ = 400 KHz (at 20/sup 0/C) and a collector base leakage current = 200 ..mu..A (at 350/sup 0/C).

Zipperian, T.E.; Dawson, L.R.; Caffin, R.J.

1981-03-01T23:59:59.000Z

133

Thermoelectric Bulk Materials from the Explosive Consolidation...  

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

Bulk Materials from the Explosive Consolidation of Nanopowders Thermoelectric Bulk Materials from the Explosive Consolidation of Nanopowders Describes technique of explosively...

134

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...

135

aluminium nitrides: Topics by E-print Network  

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

(more) Mutombo, Faustin Kalenda 2012-01-01 22 Carbon Nitride and Conjugated Polymer Composite Materials. Open Access Theses and Dissertations Summary: ??The semiconductor and...

136

americium nitrides: Topics by E-print Network  

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

heterostructure Zhang, Hongtao 2006-01-01 19 Carbon Nitride and Conjugated Polymer Composite Materials. Open Access Theses and Dissertations Summary: ??The semiconductor and...

137

aligned carbon nitride: Topics by E-print Network  

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

22 23 24 25 Next Page Last Page Topic Index 1 Carbon Nitride and Conjugated Polymer Composite Materials. Open Access Theses and Dissertations Summary: ??The semiconductor and...

138

III-Nitride Nanowires: Emerging Materials for Lighting and Energy...  

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

building blocks in LEDs, lasers, sensors, photovoltaics, and high power and high speed electronics. Compared to planar films, III-nitride nanowires have several potential...

139

Method for locating metallic nitride inclusions in metallic alloy ingots  

DOE Patents [OSTI]

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.

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

1992-01-01T23:59:59.000Z

140

Specific interaction of fluoride ions with aluminum and gallium solvates in an ethylene glycol solutions  

SciTech Connect (OSTI)

The interaction of aluminum chloride and gallium chloride with KF in ethylene glycol solutions with F:M/sup 3 +/ mole ratios approximately equal to 2 includes a step involving the formation of fluorine-containing species, in which the fluoride ions are held in the outer sphere of ethylene glycol solvates of aluminum and gallium. Complexes based on hexacoordinate solvates predominate in the solutions of aluminum, while in the case of gallium, in contrast to aluminum, the coexistence of tetra- and hexacoordinate complexes is characteristic. The configurational equilibrium in the solutions of gallium is one of the causes of the structurization of the solutions, i.e., polymerization due to the formation of H bonds between the fluoride ions and the coordinated ethylene glycol molecules.

Petrosyants, S.P.; Tsabel', E.R.; Buslaev, Yu.A.

1986-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "bulk gallium nitride" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

GALLIUM--2002 29.1 References that include a section mark () are found in the Internet  

E-Print Network [OSTI]

consumed in the United States was in the form of GaAs. GaAs was manufactured into optoelectronic devices application for gallium, with 46% of total consumption. Optoelectronic devices accounted for 42% of domestic

142

Fabrication of optoelectronic microwave linear and ring resonators on a gallium arsenide substrate  

E-Print Network [OSTI]

FABRICATION OF OPTOELECTRONIC MICROWAVE LINEAR AND RING RESONATORS ON A GALLIUM ARSENIDE SUBSTRATE A Thesis by CHUN-LIANG YEH Submitted to the Office of Graduate Studies of Texas ASM University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE August 1993 Major Subject: Electrical Engineering FABRICATION OF OPTOELECTRONIC MICROWAVE LINEAR AND RING RESONATORS ON A GALLIUM ARSENIDE SUBSTRATE A Thesis by CHUN-LIANG YEH Approved as to style and content by: Mark...

Yeh, Chun-Liang

1993-01-01T23:59:59.000Z

143

First Results of the Testing of the Liquid Gallium Jet Limiter Concept for ISTTOK  

SciTech Connect (OSTI)

The use of liquid metals as plasma facing components in tokamaks has recently experienced a renewed interest stimulated by their advantages to the development of a fusion reactor. Liquid metals have been proposed to solve problems related to the erosion and neutronic activation of solid walls submitted to high power loads allowing an efficient heat exhaustion from fusion devices. Presently the most promising materials are Lithium and Gallium. ISTTOK, a small size tokamak, will be used to test the behavior of a liquid Gallium jet in the vacuum chamber and its influence on the plasma. This paper presents a description of the conceived setup as well as experimental results. The liquid Gallium jet is generated by hydrostatic pressure and injected in a radial position close to a moveable stainless steel limiter. Both the jet and the limiter positions are variable allowing for a controlled exposure of the liquid Gallium to the edge plasma. The main components of the Gallium loop are a MHD pump, the liquid metal injector and a filtering system. The MHD pump is of the induction type, based on rotating permanent magnets. The injector is build from a stainless steel pipe ended by a shaping nozzle. A setup has been developed to introduce oxide-free Gallium inside the loop's main supply tank. Raw liquid metal is placed inside a chamber heated and degassed under high vacuum while clean Gallium is extracted from the main body of the liquefied metal. Prior to installation on the tokamak, the experimental rig has been implemented using a Pyrex tube as test chamber to investigate the stability of the Gallium jet and its break-up length for several nozzle sizes. Results are presented in this paper. This rig was also useful to assess the behavior of the overall implemented apparatus.

Gomes, R. B.; Fernandes, H.; Silva, C.; Borba, D.; Carvalho, B.; Varandas, C. [Associacao EURATOM/IST, Centro de FuSao Nuclear, Av. Rovisco Pais, 1049-001 Lisbon (Portugal); Lielausis, O.; Klyukin, A.; Platacis, E.; Mikelsons, A.; Platnieks, I. [Association EURATOM/University of Latvia, Institute of Physics, 32 Miera Str., Salaspils, LV-2169 (Latvia)

2006-12-04T23:59:59.000Z

144

Study of Magnetohydrodynamic Surface Waves on Liquid Gallium  

SciTech Connect (OSTI)

Magnetohydrodynamic (MHD) surface waves on liquid gallium are studied theoretically and experimentally in the small magnetic Reynolds number limit. A linear dispersion relation is derived when a horizontal magnetic field and a horizontal electric current is imposed. No wave damping is found in the shallow liquid limit while waves always damp in the deep liquid limit with a magnetic field parallel to the propagation direction. When the magnetic field is weak, waves are weakly damped and the real part of the dispersion is unaffected, while in the opposite limit waves are strongly damped with shortened wavelengths. In a table-top experiment, planar MHD surface waves on liquid gallium are studied in detail in the regime of weak magnetic field and deep liquid. A non-invasive diagnostic accurately measures surface waves at multiple locations by reflecting an array of lasers off the surface onto a screen, which is recorded by an Intensified-CCD camera. The measured dispersion relation is consistent with the linear theory with a reduced surface tension likely due to surface oxidation. In excellent agreement with linear theory, it is observed that surface waves are damped only when a horizontal magnetic field is imposed parallel to the propagation direction. No damping is observed under a perpendicular magnetic field. The existence of strong wave damping even without magnetic field suggests the importance of the surface oxide layer. Implications to the liquid metal wall concept in fusion reactors, especially on the wave damping and a Rayleigh-Taylor instability when the Lorentz force is used to support liquid metal layer against gravity, are discussed.

Hantao Ji; William Fox; David Pace; H.L. Rappaport

2004-05-13T23:59:59.000Z

145

High-Temperature Decomposition of Brønsted Acid Sites in Gallium-Substituted Zeolites  

SciTech Connect (OSTI)

The dehydroxylation of Broensted acid sites (BAS) in Ga-substituted zeolites was investigated at temperatures up to 850 C using X-ray absorption spectroscopy (XAS), Fourier transform infrared spectroscopy (FTIR), and mass spectrometry-temperature programmed desorption (MS-TPD). X-ray absorption near-edge spectroscopy (XANES) revealed that the majority of gallium has tetrahedral coordination even after complete dehydroxylation. The interatomic gallium-oxygen distance and gallium coordination number determined by extended X-ray absorption fine structure (EXAFS) are consistent with gallium in tetrahedral coordination at low T (< 550 C). Upon heating Ga-Beta and Ga-ZSM5 to 850 C, analysis of the EXAFS showed that 70 and 80% of the gallium was still in tetrahedral coordination. The remainder of the gallium was found to be in octahedral coordination. No trigonal Ga atoms were observed. FTIR measurements carried out at similar temperatures show that the intensity of the OH vibration due to BAS has been eliminated. MS-TPD revealed that hydrogen in addition to water evolved from the samples during dehydroxylation. This shows that dehydrogenation in addition to dehydration is a mechanism that contributes to BAS decomposition. Dehydrogenation was further confirmed by exposing the sample to hydrogen to regenerate some of the BAS as monitored by FTIR and MS-TPD.

K Al-majnouni; N Hould; W Lonergan; D Vlachos; R Lobo

2011-12-31T23:59:59.000Z

146

Method for producing silicon nitride/silicon carbide composite  

DOE Patents [OSTI]

Silicon carbide/silicon nitride composites are prepared by carbothermal reduction of crystalline silica powder, carbon powder and optionally crsytalline silicon nitride powder. The crystalline silicon carbide portion of the composite has a mean number diameter less than about 700 nanometers and contains nitrogen.

Dunmead, Stephen D. (Midland, MI); Weimer, Alan W. (Midland, MI); Carroll, Daniel F. (Midland, MI); Eisman, Glenn A. (Midland, MI); Cochran, Gene A. (Midland, MI); Susnitzky, David W. (Midland, MI); Beaman, Donald R. (Midland, MI); Nilsen, Kevin J. (Midland, MI)

1996-07-23T23:59:59.000Z

147

Process for making boron nitride using sodium cyanide and boron  

DOE Patents [OSTI]

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.

Bamberger, Carlos E. (Oak Ridge, TN)

1990-01-01T23:59:59.000Z

148

Atomic Layer Deposition of Insulating Hafnium and Zirconium Nitrides  

E-Print Network [OSTI]

author. E-mail: gordon@chemistry.harvard.edu. (1) Toth, L. E. Transition Metal Carbides and Nitrides homoleptic tetrakis(dialkylamido)- metal(IV) complexes and ammonia at low substrate temperatures (150-250 °C). The precursor vapors were alternately pulsed into a heated reactor, yielding 1.15-1.20 � of metal nitride film

149

Oxidation Protection of Uranium Nitride Fuel using Liquid Phase Sintering  

SciTech Connect (OSTI)

Two methods are proposed to increase the oxidation resistance of uranium nitride (UN) nuclear fuel. These paths are: (1) Addition of USi{sub x} (e.g. U3Si2) to UN nitride powder, followed by liquid phase sintering, and (2) 'alloying' UN nitride with various compounds (followed by densification via Spark Plasma Sintering or Liquid Phase Sintering) that will greatly increase oxidation resistance. The advantages (high thermal conductivity, very high melting point, and high density) of nitride fuel have long been recognized. The sodium cooled BR-10 reactor in Russia operated for 18 years on uranium nitride fuel (UN was used as the driver fuel for two core loads). However, the potential advantages (large power up-grade, increased cycle lengths, possible high burn-ups) as a Light Water Reactor (LWR) fuel are offset by uranium nitride's extremely low oxidation resistance (UN powders oxidize in air and UN pellets decompose in hot water). Innovative research is proposed to solve this problem and thereby provide an accident tolerant LWR fuel that would resist water leaks and high temperature steam oxidation/spalling during an accident. It is proposed that we investigate two methods to increase the oxidation resistance of UN: (1) Addition of USi{sub x} (e.g. U{sub 3}Si{sub 2}) to UN nitride powder, followed by liquid phase sintering, and (2) 'alloying' UN nitride with compounds (followed by densification via Spark Plasma Sintering) that will greatly increase oxidation resistance.

Dr. Paul A. Lessing

2012-03-01T23:59:59.000Z

150

JOURNAL OF MATERIALS SCIENCE 40 (2005) 2101 2103 LETTERS Pressureless sintering of silicon nitride/boron nitride  

E-Print Network [OSTI]

, West Lafayette, Indiana 47907-2044, USA Silicon nitride (Si3N4) and boron nitride (BN) are ma- terials2O3 (Alcoa A- 16SG, 0.4 µm in diameter) and 4 wt% Y2O3 (Alfa Aesar REacton, 10 µm in diameter

Trice, Rodney W.

151

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

DOE Patents [OSTI]

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.

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

2010-03-02T23:59:59.000Z

152

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

DOE Patents [OSTI]

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.

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)

2007-05-01T23:59:59.000Z

153

By Deborah A. Kramer No gallium production was reported in the McDonnell Douglas Corp. reportedly will world producers were Australia, Germany, and  

E-Print Network [OSTI]

facility in optoelectronic devices [light-emitting diodes France from stockpiled crude gallium produced, and in 1994. Although the total quantity of gallium used in optoelectronic devices increased, its percentage

154

Control of interface fracture in silicon nitride ceramics: influence of different rare earth elements  

SciTech Connect (OSTI)

The toughness of self-reinforced silicon nitride ceramics is improved by enhancing crack deflection and crack bridging mechanisms. Both mechanisms rely on the interfacial debonding process between the elongated {Beta}-Si{sub 3}N{sub 4} grains and the intergranular amorphous phases. The various sintering additives used for densification may influence the interfacial debonding process by modifying the thermal and mechanical properties of the intergranular glasses, which will result in different residual thermal expansion mismatch stresses; and the atomic bonding structure across the {Beta}-Si{sub 3}N{sub 4} glass interface. Earlier studies indicated that self-reinforced silicon nitrides sintered with different rare earth additives and/or different Y{sub 2}O{sub 3}:AI{sub 2}0{sub 3} ratios could exhibit different fracture behavior that varied from intergranular to transgranular fracture. No studies have been conducted to investigate the influence of sintering additives on the interfacial fracture in silicon nitride ceramics. Because of the complexity of the material system and the extremely small scale, it is difficult to conduct quantitative analyses on the chemistry and stress states of the intergranular glass phases and to relate the results to the bulk properties. The influence of different sintering additives on the interfacial fracture behavior is assessed using model systems in which {Beta}-Si{sub 3}N{sub 4}whiskers are embedded in SIAIRE (RE: rare-earth) oxynitride glasses. By systematically varying the glass composition, the role of various rare-earth additives on interfacial fracture has been examined. Specifically, four different additives were investigated: Al{sub 2}0{sub 3}, Y{sub 2}0{sub 3}, La{sub 2}O{sub 3}, and Yb{sub 2}O{sub 3}. In addition, applying the results from the model systems, the R- curve behavior of self-reinforced silicon nitride ceramics sintered with different Y{sub 2}0{sub 3}:AI{sub 2}0{sub 3} ratios was characterized.

Sun, E.Y.; Becher, P.F.; Waters, S.B.; Hsueh, Chun-Hway; Plucknett, K.P. [Oak Ridge National Lab., TN (United States); Hoffmann, M.J. [Karlsruhe Univ. (T.H.) (Germany). Inst. fuer Keramik im Maschinenbau

1996-10-01T23:59:59.000Z

155

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

DOE Patents [OSTI]

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.

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

2002-01-01T23:59:59.000Z

156

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

DOE Patents [OSTI]

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.

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

2001-01-01T23:59:59.000Z

157

High efficiency III-nitride light-emitting diodes  

DOE Patents [OSTI]

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.

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

2013-05-28T23:59:59.000Z

158

Silicon nitride protective coatings for silvered glass mirrors  

DOE Patents [OSTI]

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.

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

1988-01-01T23:59:59.000Z

159

Conductive and robust nitride buffer layers on biaxially textured substrates  

DOE Patents [OSTI]

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.

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

2009-03-31T23:59:59.000Z

160

Silicon nitride protective coatings for silvered glass mirrors  

DOE Patents [OSTI]

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.

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

1984-07-20T23:59:59.000Z

Note: This page contains sample records for the topic "bulk gallium nitride" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Vacancy Hardening and Softening in Transition Metal Carbides and Nitrides  

SciTech Connect (OSTI)

The effects of vacancies on mechanical properties of the transition metal carbides and nitrides are studied using the ab initio pseudopotential approach. Calculated shear elastic stiffness and electronic structures show that the vacancy produces entirely different effects on the mechanical strength of groups IVb nitrides and Vb carbides. It is found that the occupation of shear-unstable metallic dd bonding states changes essentially in an opposite way for the carbides and nitrides in the presence of vacancies, resulting in different responses to shear stress. Our study provides an atomistic understanding of the anomaly in hardness for these substoichiometric materials.

Jhi, Seung-Hoon; Louie, Steven G.; Cohen, Marvin L.; Ihm, Jisoon

2001-04-09T23:59:59.000Z

162

Size dependent optical properties of Si quantum dots in Si-rich nitride/Si{sub 3}N{sub 4} superlattice synthesized by magnetron sputtering  

SciTech Connect (OSTI)

A spectroscopic ellipsometry compatible approach is reported for the optical study of Si quantum dots (QDs) in Si-rich nitride/silicon nitride (SRN/Si{sub 3}N{sub 4}) superlattice, which based on Tauc-Lorentz model and Bruggeman effective medium approximation. It is shown that the optical constants and dielectric functions of Si QDs are strongly size dependent. The suppressed imaginary dielectric function of Si QDs exhibits a single broad peak analogous to amorphous Si, which centered between the transition energies E{sub 1} and E{sub 2} of bulk crystalline Si and blue shifted toward E{sub 2} as the QD size reduced. A bandgap expansion observed by the TL model when the size of Si QD reduced is in good agreement with the PL measurement. The bandgap expansion with the reduction of Si QD size is well supported by the first-principles calculations based on quantum confinement.

So, Yong-Heng; Huang, Shujuan; Conibeer, Gavin; Green, Martin A. [ARC Photovoltaics Centre of Excellence, University of New South Wales, Sydney, New South Wales 2052 (Australia); Gentle, Angus [Physics and Advanced Materials, University of Technology Sydney, P. O. Box 123, Broadway, New South Wales 2007 (Australia)

2011-03-15T23:59:59.000Z

163

Electron backscatter diffraction of plutonium-gallium alloys  

SciTech Connect (OSTI)

At Los Alamos National Laboratory a recent experimental technique has been developed to characterize reactive metals, including plutonium arid cerium, using electron backscatter diffraction (EBSD). Microstructural characterization of plutonium and its alloys by EBSD had been previously elusive primarily because of the extreme toxicity and rapid surface oxidation rate associated with plutonium metal. The experimental techniques, which included ion-sputtering the metal surface using a scanning auger microprobe (SAM) followed by vacuum transfer of the sample from the SAM to the scanning electron microscope (SEM), used to obtain electron backscatter diffraction Kikuchi patterns (EBSPs) and orientation maps for plutonium-gallium alloys are described and the initial microstructural observations based on the analysis are discussed. Combining the SEM and EBSD observations, the phase transformation behavior between the {delta} and {var_epsilon} structures was explained. This demonstrated sample preparation and characterization technique is expected to be a powerful means to further understand phase transformation behavior, orientation relationships, and texlure in the complicated plutonium alloy systems.

Boehlert, C. J. (Carl J.); Zocco, T. G. (Thomas G.); Schulze, R. K. (Roland K.); Mitchell, J. N. (Jeremy N.); Pereyra, R. A. (Ramiro A.)

2002-01-01T23:59:59.000Z

164

Hard Magnets I: 2-17, Nitrides, Carbides Frederick Pinkerton, Chairman Structure and magnetic properties of rare-earth iron nitrides, carbides  

E-Print Network [OSTI]

Hard Magnets I: 2-17, Nitrides, Carbides Frederick Pinkerton, Chairman Structure and magnetic properties of rare-earth iron nitrides, carbides and carbonitrides (invited) Z. Altounian, X. Chen, L. X develops for R=Sm upon nitriding/carbiding with an anisotropy field that is almost double the value for Nd

Ryan, Dominic

165

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

SciTech Connect (OSTI)

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 today’s 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.

None

2012-01-01T23:59:59.000Z

166

Change in the current-carrier concentration upon doping PbTe with gallium  

SciTech Connect (OSTI)

Upon doping PbTe with gallium, both high-resistivity samples with intrinsic conductivity and low-resistivity samples with electronic conductivity (n/sub e/ = 10/sup 18/ cm/sup -3/) are produced on the PbTe-GaTe section. A thorough investigation of the dependence of the thermo-emf of Pb/sub 1-x/Ga/sub x/Te on the excess Pb and Te side showed the presence of a wide region with intrinsic conductivity. The experimental data can be explained by the fact that impure gallium in PbTe has negative Hubbard energy and stabilizes the Fermi level almost at the center of the forbidden band. At high gallium concentrations, Ga/sub 2/Te/sub 3/ precipitates at first, and then GaTe precipitates as well. The lead forming in excess transforms Ga/sup 3 +/ to Ga/sup +/, which produces the electronic conductivity in the material.

Bushmarina, G.S.; Gruzinov, B.F.; Drabkin, I.A.; Lev, E.Ya.; Moizhes, B.Ya; Suprun, S.G.

1987-07-01T23:59:59.000Z

167

Single-layer graphene on silicon nitride micromembrane resonators  

E-Print Network [OSTI]

Due to their low mass, high quality factor, and good optical properties, silicon nitride (SiN) micromembrane resonators are widely used in force and mass sensing applications, particularly in optomechanics. The metallization ...

Schmid, Silvan

168

aluminum nitride insulator: Topics by E-print Network  

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

K-r grown by a modified Bridgman tech- nique,r6 Rollins, Andrew M. 27 Low-voltage organic thin film transistors with hydrophobic aluminum nitride film as gate insulator Materials...

169

Molybdenum enhanced low-temperature deposition of crystalline silicon nitride  

DOE Patents [OSTI]

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.

Lowden, R.A.

1994-04-05T23:59:59.000Z

170

Apparatus for the production of boron nitride nanotubes  

SciTech Connect (OSTI)

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.

Smith, Michael W; Jordan, Kevin

2014-06-17T23:59:59.000Z

171

Percolation of gallium dominates the electrical resistance of focused ion beam deposited metals  

SciTech Connect (OSTI)

Metal deposition through focused ion beam (FIB) based systems is thought to result in material composed of the primary metal from the metallo-organic precursor in addition to carbon, oxygen, and gallium. We determined, through electrical resistance and chemical composition measurements on a wide range of FIB deposited platinum and tungsten lines, that the gallium ion (Ga{sup +}) concentration in the metal lines plays the dominant role in controlling the electrical resistivity. Effective medium theory, based on McLachlan's formalisms, was used to describe the relationship between the Ga{sup +} concentration and the corresponding resistivity.

Faraby, H. [Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093 (United States); DiBattista, M. [Qualcomm Technologies Incorporated, San Diego, California 92121 (United States); Bandaru, P. R., E-mail: pbandaru@ucsd.edu [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California 92093 (United States)

2014-04-28T23:59:59.000Z

172

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

SciTech Connect (OSTI)

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.

Morris, R.N.

1998-08-01T23:59:59.000Z

173

Process for preparing titanium nitride powder  

DOE Patents [OSTI]

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.

Bamberger, C.E.

1988-06-17T23:59:59.000Z

174

A boron nitride nanotube peapod thermal rectifier  

SciTech Connect (OSTI)

The precise guidance of heat from one specific location to another is paramount in many industrial and commercial applications, including thermal management and thermoelectric generation. One of the cardinal requirements is a preferential conduction of thermal energy, also known as thermal rectification, in the materials. This study introduces a novel nanomaterial for rectifying heat—the boron nitride nanotube peapod thermal rectifier. Classical non-equilibrium molecular dynamics simulations are performed on this nanomaterial, and interestingly, the strength of the rectification phenomenon is dissimilar at different operating temperatures. This is due to the contingence of the thermal flux on the conductance at the localized region around the scatterer, which varies with temperature. The rectification performance of the peapod rectifier is inherently dependent on its asymmetry. Last but not least, the favourable rectifying direction in the nanomaterial is established.

Loh, G. C., E-mail: jgloh@mtu.edu [Department of Physics, Michigan Technological University, Houghton, Michigan 49931 (United States); Institute of High Performance Computing, 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632 (Singapore); Baillargeat, D. [CNRS-International-NTU-Thales Research Alliance (CINTRA), 50 Nanyang Drive, Singapore 637553 (Singapore)

2014-06-28T23:59:59.000Z

175

Millimeter wave ferromagnetic resonance in gallium-substituted ?-iron oxide  

SciTech Connect (OSTI)

In millimeter wave frequency range, hexagonal ferrites with high uniaxial anisotropic magnetic fields are used as absorbers. These ferrites include M-type barium ferrite (BaFe{sub 12}O{sub 19}) and strontium ferrite (SrFe{sub 12}O{sub 19}), which have natural ferromagnetic resonant frequency range from 40 GHz to 60?GHz. However, the higher frequency range lacks suitable materials that support the higher frequency ferromagnetic resonance. A new series of gallium-substituted ?-iron oxides (?-Ga{sub x}Fe{sub 2?x}O{sub 3}) are synthesized which have ferromagnetic resonant frequencies appearing over the frequency range 30 GHz–150 GHz. The ?-Ga{sub x}Fe{sub 2?x}O{sub 3} is synthesized by the combination of reverse micelle and sol-gel techniques or the sol-gel method only. The particle sizes are observed to be smaller than 100 nm. In this paper, the free space magneto-optical approach has been employed to study these newly developed ?-Ga{sub x}Fe{sub 2?x}O{sub 3} particles in millimeter waves. This technique enables to obtain precise transmission spectra to determine the dielectric and magnetic properties of both isotropic and anisotropic ferrites in the millimeter wave frequency range from a single set of direct measurements. The transmittance and absorbance spectra of ?-Ga{sub x}Fe{sub 2?x}O{sub 3} are shown in this paper. Strong ferromagnetic resonances at different frequencies determined by the x parameter are found.

Chao, Liu, E-mail: liu.chao@tufts.edu; Afsar, Mohammed N. [Department of Electrical and Computer Engineering, Tufts University, Medford, Massachusetts 02155 (United States); Ohkoshi, Shin-ichi [Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

2014-05-07T23:59:59.000Z

176

Protective nitride formation on stainless steel alloys for proton exchange membrane fuel cell bipolar plates  

SciTech Connect (OSTI)

Gas nitridation has shown excellent promise to form dense, electrically conductive and corrosion-resistant Cr-nitride surface layers on Ni-Cr base alloys for use as proton exchange membrane fuel cell (PEMFC) bipolar plates. Due to the high cost of nickel, Fe-base bipolar plate alloys are needed to meet the cost targets for many PEMFC applications. Unfortunately, nitridation of Fe-base stainless steel alloys typically leads to internal Cr-nitride precipitation rather than the desired protective surface nitride layer formation, due to the high permeability of nitrogen in these alloys. This paper reports the finding that it is possible to form a continuous, protective Cr-nitride (CrN and Cr{sub 2}N) surface layer through nitridation of Fe-base stainless steel alloys. The key to form a protective Cr-nitride surface layer was found to be the initial formation of oxide during nitridation, which prevented the internal nitridation typically observed for these alloys, and resulted in external Cr-nitride layer formation. The addition of V to the alloy, which resulted in the initial formation of V{sub 2}O{sub 3}-Cr{sub 2}O{sub 3}, was found to enhance this effect, by making the initially formed oxide more amenable to subsequent nitridation. The Cr-nitride surface layer formed on model V-modified Fe-27Cr alloys exhibited excellent corrosion resistance and low interfacial contact resistance under simulated PEMFC bipolar plate conditions.

Yang, Bing [ORNL; Brady, Michael P [ORNL; Wang, Heli [National Renewable Energy Laboratory (NREL); Turner, John [National Renewable Energy Laboratory (NREL); More, Karren Leslie [ORNL; Young, David J [ORNL; Tortorelli, Peter F [ORNL; Payzant, E Andrew [ORNL; Walker, Larry R [ORNL

2007-01-01T23:59:59.000Z

177

Nanofluidics, from bulk to interfaces  

E-Print Network [OSTI]

Nanofluidics has emerged recently in the footsteps of microfluidics, following the quest of scale reduction inherent to nanotechnologies. By definition, nanofluidics explores transport phenomena of fluids at the nanometer scales. Why is the nanometer scale specific ? What fluid properties are probed at nanometric scales ? In other words, why 'nanofluidics' deserves its own brand name ? In this critical review, we will explore the vast manifold of length scales emerging for the fluid behavior at the nanoscales, as well as the associated mechanisms and corresponding applications. We will in particular explore the interplay between bulk and interface phenomena. The limit of validity of the continuum approaches will be discussed, as well as the numerous surface induced effects occuring at these scales, from hydrodynamic slippage to the various electro-kinetic phenomena originating from the couplings between hydrodynamics and electrostatics. An enlightening analogy between ion transport in nanochannels and transport in doped semi-conductors will be discussed.

Lyderic Bocquet; Elisabeth Charlaix

2009-09-03T23:59:59.000Z

178

Macroscopic Properties of Restacked, Redox-Liquid Exfoliated Graphite and Graphite Mimics Produced in Bulk Quantities  

SciTech Connect (OSTI)

The excellent properties exhibited by monolayer graphene have spurred the development of exfoliation techniques using bulk graphite to produce large quantities of pristine monolayer sheets. Development of simple chemistry to exfoliate and intercalate graphite and graphite mimics in large quantities is required for numerous applications. To determine the macroscopic behavior of restacked, exfoliated bulk materials, a systematic approach is presented using a simple, redox-liquid sonication process along to obtain large quantities of 2D and 3D hexagonally layered graphite, molybdenum disulfi de, and boron nitride, which are subsequently characterized to observe chemical and structural changes. For MoS 2 sonicated with the antioxidant sodium bisulfi te, results from Raman spectroscopy, X-ray diffraction, and electron microscopy indicate the presence of distorted phases from different polymorphs, and apparent nanotube structures in the bulk, restacked powder. Furthermore, using thermograviemtric analysis, the antioxidant enhances the resistance to oxidative degradation of MoS 2 , upon thermal treatment up to 900 C. The addition of the ionic antioxidant decreased dispersion stability in non-polar solvent, suggesting decreased compatibility with non-polar systems. Using simple chemical methods, the ability to generate tailored multidimensional layered materials with unique macroscopic properties is critical for numerous applications, including electrical devices, reinforced polymer composites, lithium ion capacitors, and chemical sensing.

Srivastava, Vikram K [ORNL; Quinlan, Ronald [ORNL; Agapov, Alexander L [ORNL; Dunlap, John R [ORNL; Nelson, Kimberly M [ORNL; Duranty, Edward R [ORNL; Sokolov, Alexei P [ORNL; Bhat, Gajanan [ORNL; Mays, Jimmy [ORNL

2014-01-01T23:59:59.000Z

179

CX-009000: Categorical Exclusion Determination  

Broader source: Energy.gov [DOE]

"High Quality, Low Cost Bulk Gallium Nitride (GaN) Substrates Grown by the Electrochemical Solution Growth Method CX(s) Applied: A9, B3.6 Date: 08/20/2012 Location(s): Missouri Offices(s): Golden Field Office"

180

Adhesion improvement of electroless copper depositions on titanium nitride by low temperature annealing  

E-Print Network [OSTI]

copper depositions onto titanium nitride, a diffusion barrier material. In particular, an effort is made to characterize the adhesion of the electronics copper deposit on titanium nitride and the improvement of the adhesion produced by low temperature...

Eiserer, Rex Anthony

1999-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "bulk gallium nitride" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Synthesis of III-V nitride nanowires with controlled structure, morphology, and composition  

E-Print Network [OSTI]

The III-V nitride materials system offers tunable electronic and optical properties that can be tailored for specific electronic and optoelectronic applications by varying the (In,Ga,Al)N alloy composition. While nitride ...

Crawford, Samuel Curtis

2014-01-01T23:59:59.000Z

182

E-Print Network 3.0 - amorphous tin nitride Sample Search Results  

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

TiN, are extensively used as wear... of transition metal nitrides (TiN, NbN) where reduction of the metal is necessary for the nitride formation... Layer Epitaxy in Deposition...

183

E-Print Network 3.0 - actinide nitrides phosphides Sample Search...  

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

vacancy scattering and Hall constant... ) of 8.4 (i.e. ThCo.6No.4). In transition metal carbides and nitrides, a similar but more pronounced... carbides, nitride and...

184

Comparing directed efficiency of III-nitride nanowire light-emitting diodes  

E-Print Network [OSTI]

III-nitride-based nanowires are a promising platform for solid-state lighting. III-nitride nanowires that act as natural waveguides to enhance directed extraction have previously been shown to be free of extended defects ...

Gradecak, Silvija

185

Feasibility of breeding in hard spectrum boiling water reactors with oxide and nitride fuels  

E-Print Network [OSTI]

This study assesses the neutronic, thermal-hydraulic, and fuel performance aspects of using nitride fuel in place of oxides in Pu-based high conversion light water reactor designs. Using the higher density nitride fuel ...

Feng, Bo, Ph. D. Massachusetts Institute of Technology

2011-01-01T23:59:59.000Z

186

Optical, electrical, and solar energy-conversion properties of gallium arsenide nanowire-array  

E-Print Network [OSTI]

Optical, electrical, and solar energy-conversion properties of gallium arsenide nanowire, and will aid in the design and optimization of nanowire-based systems for solar energy-conversion applications, and the photoelectrochemical energy-conversion properties of GaAs nanowire arrays were evaluated in contact with one

Zhou, Chongwu

187

GALLIUM--2003 28.1 References that include a section mark () are found in the Internet  

E-Print Network [OSTI]

in the United States was in the form of GaAs. GaAs was manufactured into optoelectronic devices (LEDs, laser diodes, photodetectors, and solar cells) and ICs. ICs and optoelectronic devices each accounted for 41) and optoelectronic devices [mostly laser diodes and light- emitting diodes (LEDs)]. Estimated crude gallium

188

Pulsed laser deposition of epitaxial yttrium iron garnet films with low Gilbert damping and bulk-like magnetization  

SciTech Connect (OSTI)

Yttrium iron garnet (YIG, Y {sub 3}Fe{sub 5}O{sub 12}) films have been epitaxially grown on Gadolinium Gallium Garnet (GGG, Gd{sub 3}Ga{sub 5}O{sub 12}) substrates with (100) orientation using pulsed laser deposition. The films were single-phase, epitaxial with the GGG substrate, and the root-mean-square surface roughness varied between 0.14 nm and 0.2 nm. Films with thicknesses ranging from 17 to 200 nm exhibited low coercivity (<2 Oe), near-bulk room temperature saturation moments (?135 emu cm{sup ?3}), in-plane easy axis, and damping parameters as low as 2.2 × 10{sup ?4}. These high quality YIG thin films are useful in the investigation of the origins of novel magnetic phenomena and magnetization dynamics.

Onbasli, M. C., E-mail: onbasli@mit.edu; Kim, D. H.; Ross, C. A. [Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139 (United States); Kehlberger, A. [Institute of Physics, Johannes Gutenberg-University of Mainz, 55099 Mainz (Germany); Graduate School Materials Science in Mainz, Staudinger Weg 9, 55128 Mainz (Germany); Jakob, G.; Kläui, M. [Institute of Physics, Johannes Gutenberg-University of Mainz, 55099 Mainz (Germany); Chumak, A. V.; Hillebrands, B. [Fachbereich Physik and Landesforschungszentrum, OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern (Germany)

2014-10-01T23:59:59.000Z

189

SUBMILLIMETER OPTICAL PROPERTIES OF HEXAGONAL BORON NITRIDE A. J. Gatesman, R. H. Giles and J. Waldman  

E-Print Network [OSTI]

boron nitride was obtained in four grades (A, HP, M, M26) from The Carborundum Co. in Niagara Fall, NY

Massachusetts at Lowell, University of

190

Inorganic Nanocrystal Bulk Heterojunctions - Energy Innovation...  

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

Solar Photovoltaic Solar Photovoltaic Find More Like This Return to Search Inorganic Nanocrystal Bulk Heterojunctions Brookhaven National Laboratory Contact BNL About This...

191

Commercialization of Bulk Thermoelectric Materials for Power...  

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

& Publications Commercialization of Bulk Thermoelectric Materials for Power Generation Hydrogen Embrittlement of Pipeline Steels: Causes and Remediation Distributed Bio-Oil...

192

Hyperon bulk viscosity in strong magnetic fields  

E-Print Network [OSTI]

We study the bulk viscosity of neutron star matter including $\\Lambda$ hyperons in the presence of quantizing magnetic fields. Relaxation time and bulk viscosity due to both the non-leptonic weak process involving $\\Lambda$ hyperons and direct Urca processes are calculated here. In the presence of a strong magnetic field of $10^{17}$ G, the hyperon bulk viscosity coefficient is reduced whereas bulk viscosity coefficients due to direct Urca processes are enhanced compared with their field free cases when many Landau levels are populated by protons, electrons and muons.

Monika Sinha; Debades Bandyopadhyay

2009-06-06T23:59:59.000Z

193

Recent Device Developments with Advanced Bulk Thermoelectric...  

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

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...

194

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

DOE Patents [OSTI]

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.

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

1997-07-01T23:59:59.000Z

195

DETERMINING OPTICAL CONSTANTS OF URANIUM NITRIDE THIN FILMS IN THE EXTREME  

E-Print Network [OSTI]

DETERMINING OPTICAL CONSTANTS OF URANIUM NITRIDE THIN FILMS IN THE EXTREME ULTRAVIOLET (1.6-35 NM deposition and characterization of reactively-sputtered uranium nitride thin films. I also report optical.1 Application 1 1.2 Optical Constants 2 1.3 Project Focus 7 2 Uranium Nitride Thin Films 8 2.1 Sputtering 8 2

Hart, Gus

196

Thermodynamic stability of oxide, nitride, and carbide coating materials in liquid Sn25Li  

E-Print Network [OSTI]

Thermodynamic stability of oxide, nitride, and carbide coating materials in liquid Sn­25Li S of various oxides, carbides, and nitrides in Sn­Li is estimated as a function of lithium composition K most of the studied nitrides, carbides, and some oxides were found to be stable (DrG > 0). However

Ghoniem, Nasr M.

197

Trends in elasticity and electronic structure of transition-metal nitrides and carbides from first principles  

E-Print Network [OSTI]

Trends in elasticity and electronic structure of transition-metal nitrides and carbides from first 2005 The elastic properties of selected transition-metal TM nitrides and carbides in B1 structure the transition-metal nitrides and carbides remain unclear and a challenge for engineering hard materials

Wu, Zhigang

198

Active Control of Nitride Plasmonic Dispersion in the Far Infrared.  

SciTech Connect (OSTI)

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.

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

2014-11-01T23:59:59.000Z

199

Structural studies of magnesium nitride fluorides by powder neutron diffraction  

SciTech Connect (OSTI)

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.

Brogan, Michael A. [School of Chemistry, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Hughes, Robert W. [WestCHEM, School of Chemistry, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Smith, Ronald I. [ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Didcot OX11 0QX (United Kingdom); Gregory, Duncan H., E-mail: Duncan.Gregory@glasgow.ac.uk [WestCHEM, School of Chemistry, University of Glasgow, Glasgow G12 8QQ (United Kingdom)

2012-01-15T23:59:59.000Z

200

Process for synthesizing titanium carbide, titanium nitride and titanium carbonitride  

DOE Patents [OSTI]

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.

Koc, R.; Glatzmaier, G.C.

1995-05-23T23:59:59.000Z

Note: This page contains sample records for the topic "bulk gallium nitride" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Process for synthesizing titanium carbide, titanium nitride and titanium carbonitride  

DOE Patents [OSTI]

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.

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

1995-01-01T23:59:59.000Z

202

Process for producing wurtzitic or cubic boron nitride  

DOE Patents [OSTI]

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.

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

1992-04-28T23:59:59.000Z

203

Process for producing wurtzitic or cubic boron nitride  

DOE Patents [OSTI]

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.

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

1992-01-01T23:59:59.000Z

204

Synthesis and Optimization of the Sintering Kinetics of Actinide Nitrides  

SciTech Connect (OSTI)

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.

Drryl P. Butt; Brian Jaques

2009-03-31T23:59:59.000Z

205

The Bulk Viscosity of a Pion Gas  

E-Print Network [OSTI]

We compute the bulk viscosity of a gas of pions at temperatures below the QCD crossover temperature, for the physical value of pion mass, to lowest order in chiral perturbation theory. Bulk viscosity is controlled by number-changing processes which become exponentially slow at low temperatures when the pions become exponentially dilute, leading to an exponentially large bulk viscosity zeta ~ (F_0^8/m_\\pi^5) exp(2m_\\pi/T), where F_0 = 93 MeV is the pion decay constant.

Egang Lu; Guy D. Moore

2011-01-31T23:59:59.000Z

206

Bulk viscosity of N=2* plasma  

E-Print Network [OSTI]

We use gauge theory/string theory correspondence to study the bulk viscosity of strongly coupled, mass deformed SU(N_c) N=4 supersymmetric Yang-Mills plasma, also known as N=2^* gauge theory. For a wide range of masses we confirm the bulk viscosity bound proposed in arXiv:0708.3459. For a certain choice of masses, the theory undergoes a phase transition with divergent specific heat c_V ~ |1-T_c/T|^(-1/2). We show that, although bulk viscosity rapidly grows as T -> T_c, it remains finite in the vicinity of the critical point.

Alex Buchel; Chris Pagnutti

2009-03-02T23:59:59.000Z

207

Fast neutron scattering on Gallium target at 14.8 MeV  

E-Print Network [OSTI]

Benchmarking of evaluated nuclear data libraries was performed for $\\sim 14.8$ MeV neutrons on Gallium targets. The experiments were performed at China Institute of Atomic Energy(CIAE). Solid samples of natural Gallium (3.2 cm and 6.4 cm thick) were bombarded by $\\sim 14.8$ MeV neutrons and leakage neutron energy spectra were measured at 60$^{\\circ}$ and 120$^{\\circ}$. The measured spectra are rather well reproduced by MCNP-4C simulations with the CENDL-3.1, ENDF/B-VII and JENDL-4.0 evaluated nuclear data libraries, except for the inelastic contributions around $E_{n} = 10-13$ MeV. All three libraries significantly underestimate the inelastic contributions. The inelastic contributions are further studied, using the Talys simulation code and the experimental spectra are reproduced reasonably well in the whole energy range by the Talys calculation, including the inelastic contributions.

R. Han; R. Wada; Z. Chen; Y. Nie; X. Liu; S. Zhang; P. Ren; B. Jia; G. Tian; F. Luo; W. Lin; J. Liu; F. Shi; M. Huang; X. Ruan; J. Ren; Z. Zhou; H. Huang; J. Bao; K. Zhang; B. Hu

2014-11-03T23:59:59.000Z

208

Fast neutron scattering on Gallium target at 14.8 MeV  

E-Print Network [OSTI]

Benchmarking of evaluated nuclear data libraries was performed for $\\sim 14.8$ MeV neutrons on Gallium targets. The experiments were performed at China Institute of Atomic Energy(CIAE). Solid samples of natural Gallium (3.2 cm and 6.4 cm thick) were bombarded by $\\sim 14.8$ MeV neutrons and leakage neutron energy spectra were measured at 60$^{\\circ}$ and 120$^{\\circ}$. The measured spectra are rather well reproduced by MCNP-4C simulations with the CENDL-3.1, ENDF/B-VII and JENDL-4.0 evaluated nuclear data libraries, except for the inelastic contributions around $E_{n} = 10-13$ MeV. All three libraries significantly underestimate the inelastic contributions. The inelastic contributions are further studied, using the Talys simulation code and the experimental spectra are reproduced reasonably well in the whole energy range by the Talys calculation, including the inelastic contributions.

Han, R; Chen, Z; Nie, Y; Liu, X; Zhang, S; Ren, P; Jia, B; Tian, G; Luo, F; Lin, W; Liu, J; Shi, F; Huang, M; Ruan, X; Ren, J; Zhou, Z; Huang, H; Bao, J; Zhang, K; Hu, B

2014-01-01T23:59:59.000Z

209

OXIDE / LPCVD NITRIDE STACKS ON SILICON: THE EFFECTS OF HIGH TEMPERATURE TREATMENTS ON BULK LIFETIME AND ON SURFACE PASSIVATION.  

E-Print Network [OSTI]

phosphorous diffusion (830°C for 30 minutes R[ ~800-1000/[#12; D WKHUPDOO\\ JURZQ R[LGH °C or 1100°C

210

Narrow energy band gap gallium arsenide nitride semi-conductors and an ion-cut-synthesis method for producing the same  

DOE Patents [OSTI]

A method for forming a semi-conductor material is provided that comprises forming a donor substrate constructed of GaAs, providing a receiver substrate, implanting nitrogen into the donor substrate to form an implanted layer comprising GaAs and nitrogen. The implanted layer is bonded to the receiver substrate and annealed to form GaAsN and nitrogen micro-blisters in the implanted layer. The micro-blisters allow the implanted layer to be cleaved from the donor substrate.

Weng, Xiaojun; Goldman, Rachel S.

2006-06-06T23:59:59.000Z

211

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)

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.

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)

2013-12-02T23:59:59.000Z

212

Cubic Lithium Nitride Amy Lazicki1,2  

E-Print Network [OSTI]

Cubic Lithium Nitride to 200 GPa Amy Lazicki1,2 Choong-Shik Yoo1, Warren Pickett2, Richard electrolyte material for lithium-based batteries · possible hydrogen storage material Thrust of this research ­ differences between the XRS and PDOS are indications of the presence of core-hole interactions (excitons

Islam, M. Saif

213

Evaluation and silicon nitride internal combustion engine components  

SciTech Connect (OSTI)

The feasibility of silicon nitride (Si[sub 3]N[sub 4]) use in internal combustion engines was studied by testing three different components for wear resistance and lower reciprocating mass. The information obtained from these preliminary spin rig and engine tests indicates several design changes are necessary to survive high-stress engine applications. The three silicon nitride components tested were valve spring retainers, tappet rollers, and fuel pump push rod ends. Garrett Ceramic Components' gas-pressure sinterable Si[sub 3]N[sub 4] (GS-44) was used to fabricate the above components. Components were final machined from densified blanks that had been green formed by isostatic pressing of GS-44 granules. Spin rig testing of the valve spring retainers indicated that these Si[sub 3]N[sub 4] components could survive at high RPM levels (9,500) when teamed with silicon nitride valves and lower spring tension than standard titanium components. Silicon nitride tappet rollers showed no wear on roller O.D. or I.D. surfaces, steel axles and lifters; however, due to the uncrowned design of these particular rollers the cam lobes indicated wear after spin rig testing. Fuel pump push rod ends were successful at reducing wear on the cam lobe and rod end when tested on spin rigs and in real-world race applications.

Voldrich, W. (Allied-Signal Aerospace Co., Torrance, CA (United States). Garrett Ceramic Components Div.)

1992-04-01T23:59:59.000Z

214

Continuous Fiber Ceramic Composite (CFCC) Program: Gaseous Nitridation  

SciTech Connect (OSTI)

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

R. Suplinskas G. DiBona; W. Grant

2001-10-29T23:59:59.000Z

215

Polyorganosilazane preceramic binder development for reaction bonded silicon nitride composites  

SciTech Connect (OSTI)

This study has examined the use of two commercially available polyorganosilazanes for application as preceramic binders in a composite composed of silicon carbide fibers in a reaction bonded silicon nitride (RBSN) matrix. Ceramic monolithic and composite samples were produced. Density of monolithic and whisker reinforced RBSN samples containing the polysilazane binder was increased. Mercury intrusion porosimetry revealed a significant decrease in the pore sizes of samples containing a polyorganosilazane binder. Electron micrographs of samples containing the preceramic binder looked similar to control samples containing no precursor. Overall, incorporation of the polysilazane into monolithic and whisker reinforced samples resulted in significantly increased density and decreased porosity. Nitriding of the RBSN was slightly retarded by addition of the polysilazane binder. Samples with the preceramic binders contained increased contents of {alpha} versus {beta}-silicon nitride which may be due to interaction of hydrogen evolved from polysilazane pyrolysis with the nitriding process. Initial efforts to produce continuous fiber reinforced composites via this method have not realized the same improvements in density and porosity which have been observed for monolithic and whisker reinforced samples. Further, the addition of perceramic binder resulted in a more brittle fracture morphology as compared to similar composites made without the binder.

Mohr, D.L.; Starr, T.L. [Georgia Tech Research Inst., Atlanta, GA (United States)

1992-11-01T23:59:59.000Z

216

Polyorganosilazane preceramic binder development for reaction bonded silicon nitride composites  

SciTech Connect (OSTI)

This study has examined the use of two commercially available polyorganosilazanes for application as preceramic binders in a composite composed of silicon carbide fibers in a reaction bonded silicon nitride (RBSN) matrix. Ceramic monolithic and composite samples were produced. Density of monolithic and whisker reinforced RBSN samples containing the polysilazane binder was increased. Mercury intrusion porosimetry revealed a significant decrease in the pore sizes of samples containing a polyorganosilazane binder. Electron micrographs of samples containing the preceramic binder looked similar to control samples containing no precursor. Overall, incorporation of the polysilazane into monolithic and whisker reinforced samples resulted in significantly increased density and decreased porosity. Nitriding of the RBSN was slightly retarded by addition of the polysilazane binder. Samples with the preceramic binders contained increased contents of [alpha] versus [beta]-silicon nitride which may be due to interaction of hydrogen evolved from polysilazane pyrolysis with the nitriding process. Initial efforts to produce continuous fiber reinforced composites via this method have not realized the same improvements in density and porosity which have been observed for monolithic and whisker reinforced samples. Further, the addition of perceramic binder resulted in a more brittle fracture morphology as compared to similar composites made without the binder.

Mohr, D.L.; Starr, T.L. (Georgia Tech Research Inst., Atlanta, GA (United States))

1992-11-01T23:59:59.000Z

217

Methods for improved growth of group III nitride buffer layers  

DOE Patents [OSTI]

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).

Melnik, Yurity; Chen, Lu; Kojiri, Hidehiro

2014-07-15T23:59:59.000Z

218

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

SciTech Connect (OSTI)

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.

Shanmugam, Mariyappan; Jain, Nikhil; Jacobs-Gedrim, Robin; Yu, Bin, E-mail: byu@albany.edu [College of Nanoscale Science and Engineering, State University of New York, Albany, New York 12203 (United States)] [College of Nanoscale Science and Engineering, State University of New York, Albany, New York 12203 (United States); Xu, Yang [Institute of Microelectronics and Optoelectronics, Zhejiang University, Hangzhou 310027 (China)] [Institute of Microelectronics and Optoelectronics, Zhejiang University, Hangzhou 310027 (China)

2013-12-09T23:59:59.000Z

219

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...

220

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

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

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...

Note: This page contains sample records for the topic "bulk gallium nitride" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

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...

222

Bulk Hydrogen Storage - Strategic Directions for Hydrogen Delivery...  

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

Bulk Hydrogen Storage - Strategic Directions for Hydrogen Delivery Workshop Bulk Hydrogen Storage - Strategic Directions for Hydrogen Delivery Workshop Targets, barriers and...

223

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

DOE Patents [OSTI]

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.

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

2001-01-01T23:59:59.000Z

224

Gallium Lighting, LLC, Accepts Inaugural Position on the Industry Advisory Board of UC-Light Center to Help Bring Wireless Data  

E-Print Network [OSTI]

Gallium Lighting, LLC, Accepts Inaugural Position on the Industry Advisory Board of UC-Light Center to Help Bring Wireless Data Communications Capabilities to LED Lights Fayetteville, GA ­ February 10, 2011 ­Gallium Lighting, LLC, announced today it has accepted an inaugural position

225

Micro benchtop optics by bulk silicon micromachining  

DOE Patents [OSTI]

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.

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

2000-01-01T23:59:59.000Z

226

E-Print Network 3.0 - aluminum nitride films Sample Search Results  

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

6 CHARGE STABILITY IN LPCVD SILICON NITRIDE FOR SURFACE PASSIVATION OF SILICON SOLAR CELLS Summary: the distribution and stability of negative charge in silicon dioxide ...

227

Synthesis and Functionalization of Carbon and Boron Nitride Nanomaterials and Their Applications  

E-Print Network [OSTI]

Carbon Nitrides for Hydrogen Storage. Adv. Funct. Mater.N compounds for chemical hydrogen storage. Chemical SocietyT. , High-Pressure Hydrogen Storage in Zeolite-Templated

Erickson, Kristopher John

2012-01-01T23:59:59.000Z

228

amorphous carbon-nitride films: Topics by E-print Network  

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

in hard and elastic amorphous carbon nitride films investigated H NMR spectroscopy Materials Science Websites Summary: Received 14 February 2003; published 5 November 2003 The...

229

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

DOE Patents [OSTI]

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.

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

2008-03-18T23:59:59.000Z

230

E-Print Network 3.0 - aluminum nitride ceramics Sample Search...  

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

Emily Parker, Vanni Lughi, Noel C. MacDonald Summary: , biocompatibility, and high fracture toughness. As a piezoelectric ceramic, aluminum nitride is compatible... Aluminum...

231

E-Print Network 3.0 - aluminum nitride thin Sample Search Results  

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

thin Search Powered by Explorit Topic List Advanced Search Sample search results for: aluminum nitride thin Page: << < 1 2 3 4 5 > >> 1 Packaging Design for Lawrence Berkeley...

232

E-Print Network 3.0 - actinide bearing nitride Sample Search...  

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

> >> 41 Electronic structure and pairwise interactions in substoichiometric transition metal carbides and nitrides Summary: ) of transition metals, rare earths and actinides in...

233

E-Print Network 3.0 - aluminum nitride coatings Sample Search...  

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

nitride... was attributed to the formation of a layer of aluminum ... Source: zur Loye, Hans-Conrad - Department of Chemistry and Biochemistry, University of South Carolina...

234

2009 Minerals Yearbook U.S. Department of the Interior  

E-Print Network [OSTI]

As and gallium nitride (GaN) and was used in integrated circuits (ICs) and optoelectronic devices [laser diodes

235

Purification of boron nitride nanotubes via polymer wrapping  

SciTech Connect (OSTI)

Highlights: ? Surface modification of boron nitride nanotubes using polymeric materials. ? Surface-modified BNNT was purified with a simple dilution-centrifugation step. ? Surface-modified BNNT can be directly used for polymer composite fabrication ? Degree of purification was analyzed by Raman spectroscopy. - Abstract: Boron nitride nanotubes (BNNT) synthesized by a ball milling-annealing were surface-modified using three different types of polymeric materials. Those materials were chosen depending on future applications especially in polymer nanocomposite fabrications. We found that the surface-modified BNNT can be purified with a simple dilution-centrifugation step, which would be suitable for large-scale purification. Degree of purification was monitored by means of the center peak position and FWHM of E{sub 2g} mode of BNNT in Raman spectra. As the purification of BNNT develops, the peak position was up-shifted while FWHM of the peak was narrowed.

Choi, Jin-Hyuk [Department of Nano Science and Technology, Sejong University, 98 Gunja, Gwangjin, Seoul 143-747 (Korea, Republic of); Kim, Jaewoo [Nuclear Materials Research Division, Korea Atomic Energy Research Institute, 1045 Daedukdaero, Daejeon 305-353 (Korea, Republic of); WCI Quantum Beam based Radiation Research Center, Korea Atomic Energy Research Institute, 1045 Daedukdaero, Daejeon 305-353 (Korea, Republic of); Seo, Duckbong [Nuclear Materials Research Division, Korea Atomic Energy Research Institute, 1045 Daedukdaero, Daejeon 305-353 (Korea, Republic of); Seo, Young-Soo, E-mail: ysseo@sejong.ac.kr [Department of Nano Science and Technology, Sejong University, 98 Gunja, Gwangjin, Seoul 143-747 (Korea, Republic of)

2013-03-15T23:59:59.000Z

236

Chemical preparation and shock wave compression of carbon nitride precursors  

SciTech Connect (OSTI)

Two synthetic routes have been developed to produce high-molecular-weight organic precursors containing a high weight fraction of nitrogen. One of the precursors is a pyrolysis residue of melamine-formaldehyde resin. The second precursor is the byproduct of an unusual low-temperature combustion reaction of tetrazole and its sodium salt. These precursors have been shock compressed under typical conditions for diamond and wurtzite boron nitride synthesis in an attempt to recover a new ultrahard carbon nitride. The recovered material has been analyzed by X-ray diffraction, FTIR, and Raman microprobe analysis. Diamond is present in the recovered material. This diamond is well ordered relative to diamond shock synthesized from carbonaceous starting materials.

Wixon, M.R. (KMS Fusion, Inc., Ann Arbor, MI (USA))

1990-07-01T23:59:59.000Z

237

Electrically dependent bandgaps in graphene on hexagonal boron nitride  

SciTech Connect (OSTI)

We present first-principles calculations on the bandgap of graphene on a layer of hexagonal boron nitride in three different stacking configurations. Relative stability of the configurations is identified and bandgap tunability is demonstrated through the application of an external, perpendicularly applied electric field. We carefully examine the bandgap's sensitivity to both magnitude of the applied field as well as separation between the graphene and hexagonal boron nitride layers. Features of the band structure are examined and configuration-dependent relationships between the field and bandgap are revealed and elucidated through the atom-projected density of states. These findings suggest the potential for opening and modulating a bandgap in graphene as high as several hundred meV.

Kaplan, D., E-mail: daniel.b.kaplan.civ@mail.mil; Swaminathan, V. [U.S. Army RDECOM-ARDEC, Fuze Precision Armaments and Technology Directorate, Picatinny Arsenal, New Jersey 07806 (United States); Recine, G. [Department of Applied Physics, Polytechnic Institute of New York University, Brooklyn, New York 11201 (United States); Department of Physics and Engineering Physics, Fordham University, Bronx, New York 10458 (United States)

2014-03-31T23:59:59.000Z

238

Development of silicon nitride composites with continuous fiber reinforcement  

SciTech Connect (OSTI)

The composites were fabricated using ultrafine Si powders prepared by attritor milling; the powders exhibits full conversion to Si nitride in < 3 h at {le} 1200 C (these conditions reduce degradation of the fibers compared to conventional). Effects of processing conditions on fiber properties and the use of fiber coatings to improve stability during processing as well as change the fiber-matrix interfacial properties were investigated. A duplex carbon-silicon carbide coating, deposited by CVD, reduced fiber degradation in processing, and it modified the fiber-matrix adhesion. Si nitride matrix composites were fabricated using reaction sintering, forming laminates, filament-wound plates, and tubes. In each case, an attritor milled Si powder slurry is infiltrated into ceramic fiber preforms or tows, which are then assembled to form a 3-D structure for reaction sintering. The resulting composites have properties comparable to chemical vapor infiltration densified composites, with reasonable strengths and graceful composite fracture behavior.

Starr, T.L.; Mohr, D.L.; Lackey, W.J.; Hanigofsky, J.A. [Georgia Inst. of Tech., Atlanta, GA (United States). Georgia Technology Research Inst.

1993-10-01T23:59:59.000Z

239

Ion implantation of silicon nitride ball bearings  

SciTech Connect (OSTI)

Hypothesis for ion implantation effect was that stress concentrations reflected into the bulk due to topography such as polishing imperfections, texture in the race, or transferred material, might be reduced due to surface amorphization. 42 control samples were tested to an intended runout period of 60 h. Six ion implanted balls were tested to an extended period of 150 h. Accelerated testing was done in a V groove so that wear was on two narrow wear tracks. Rutherford backscattering, XRPS, profilometry, optical microscopy, nanoindentation hardness, and white light interferometry were used. The balls were implanted with 150-keV C ions at fluence 1.1x10{sup 17}/cm{sup 2}. The samples had preexisting surface defects (C-cracks), so the failure rate of the control group was unacceptable. None of the ion-implanted samples failed in 150 h of testing. Probability of randomly selecting 6 samples from the control group that would perform this well is about 5%, so there is good probability that ion implantation improved performance. Possible reasons are discussed. Wear tracks, microstructure, and impurity content were studied in possible relation to C-cracks.

Williams, J.M. [Oak Ridge National Lab., TN (United States); Miner, J.R. [United Technologies, Pratt and Whitney, West Palm Beach, FL (United States)

1996-09-01T23:59:59.000Z

240

Charge carrier transport properties in layer structured hexagonal boron nitride  

SciTech Connect (OSTI)

Due to its large in-plane thermal conductivity, high temperature and chemical stability, large energy band gap (~ 6.4 eV), hexagonal boron nitride (hBN) has emerged as an important material for applications in deep ultraviolet photonic devices. Among the members of the III-nitride material system, hBN is the least studied and understood. The study of the electrical transport properties of hBN is of utmost importance with a view to realizing practical device applications. Wafer-scale hBN epilayers have been successfully synthesized by metal organic chemical deposition and their electrical transport properties have been probed by variable temperature Hall effect measurements. The results demonstrate that undoped hBN is a semiconductor exhibiting weak p-type at high temperatures (> 700?°K). The measured acceptor energy level is about 0.68 eV above the valence band. In contrast to the electrical transport properties of traditional III-nitride wide bandgap semiconductors, the temperature dependence of the hole mobility in hBN can be described by the form of ? ? (T/T{sub 0}){sup ??} with ? = 3.02, satisfying the two-dimensional (2D) carrier transport limit dominated by the polar optical phonon scattering. This behavior is a direct consequence of the fact that hBN is a layer structured material. The optical phonon energy deduced from the temperature dependence of the hole mobility is ?? = 192 meV (or 1546 cm{sup -1}), which is consistent with values previously obtained using other techniques. The present results extend our understanding of the charge carrier transport properties beyond the traditional III-nitride semiconductors.

Doan, T. C.; Li, J.; Lin, J. Y.; Jiang, H. X., E-mail: hx.jiang@ttu.edu [Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, Texas 79409 (United States)

2014-10-15T23:59:59.000Z

Note: This page contains sample records for the topic "bulk gallium nitride" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Decision Models for Bulk Energy Transportation Networks  

E-Print Network [OSTI]

-mouth generation at Powder River Basin · How much impact would 25% wind penetration have on price ? 2 What is modeled · spatial & temporal · energy flows · nodal prices (fuel & elec) · SO2, allowance price1 Decision Models for Bulk Energy Transportation Networks Electrical Engineering Professor Jim Mc

Tesfatsion, Leigh

242

INVESTIGATION OF BULK POWER ERCOT (Texas)  

E-Print Network [OSTI]

. . . . . . . . . . . . . . . . . . . . . . . . 4-4 D. The New Wholesale Market and the Move Toward Retail Choice . . . . . . . . . . 4-6 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13 1. The Short-Term Energy Market . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4INVESTIGATION OF BULK POWER MARKETS ERCOT (Texas) November 1, 2000 The analyses and conclusions

Laughlin, Robert B.

243

Nitridation under ammonia of high surface area vanadium aerogels  

SciTech Connect (OSTI)

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.

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)

2005-01-15T23:59:59.000Z

244

Dual operation characteristics of resistance random access memory in indium-gallium-zinc-oxide thin film transistors  

SciTech Connect (OSTI)

In this study, indium-gallium-zinc-oxide thin film transistors can be operated either as transistors or resistance random access memory devices. Before the forming process, current-voltage curve transfer characteristics are observed, and resistance switching characteristics are measured after a forming process. These resistance switching characteristics exhibit two behaviors, and are dominated by different mechanisms. The mode 1 resistance switching behavior is due to oxygen vacancies, while mode 2 is dominated by the formation of an oxygen-rich layer. Furthermore, an easy approach is proposed to reduce power consumption when using these resistance random access memory devices with the amorphous indium-gallium-zinc-oxide thin film transistor.

Yang, Jyun-Bao; Chen, Yu-Ting; Chu, Ann-Kuo [Department of Photonics, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Chang, Ting-Chang, E-mail: tcchang@mail.phys.nsysu.edu.tw [Department of Photonics, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Department of Physics, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Advanced Optoelectronics Technology Center, National Cheng Kung University, Taiwan (China); Huang, Jheng-Jie; Chen, Yu-Chun; Tseng, Hsueh-Chih [Department of Physics, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Sze, Simon M. [Department of Physics, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Department of Electronics Engineering, National Chiao Tung University, Hsinchu, Taiwan (China)

2014-04-14T23:59:59.000Z

245

Synthesis of graphene nanoribbons from amyloid templates by gallium vapor-assisted solid-phase graphitization  

SciTech Connect (OSTI)

Single- and double-layer graphene nanoribbons (GNRs) with widths of around 10?nm were synthesized directly onto an insulating substrate by solid-phase graphitization using a gallium vapor catalyst and carbon templates made of amyloid fibrils. Subsequent investigation revealed that the crystallinity, conductivity, and carrier mobility were all improved by increasing the temperature of synthesis. The carrier mobility of the GNR synthesized at 1050?°C was 0.83 cm{sup 2}/V?s, which is lower than that of mechanically exfoliated graphene. This is considered to be most likely due to electron scattering by the defects and edges of the GNRs.

Murakami, Katsuhisa, E-mail: k.murakami@bk.tsukuba.ac.jp; Dong, Tianchen; Kajiwara, Yuya; Takahashi, Teppei; Fujita, Jun-ichi [Institute of Applied Physics, Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Tsukuba Research Center for Interdisciplinary Materials Science, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Hiyama, Takaki; Takai, Eisuke; Ohashi, Gai; Shiraki, Kentaro [Institute of Applied Physics, Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan)

2014-06-16T23:59:59.000Z

246

Surface and Coatings Technology 102 (1998) 9096 Effects of argon irradiation on a plasma-nitrided carbon steel  

E-Print Network [OSTI]

-nitrided carbon steel G. Simon, M.A.Z. Vasconcellos, C.A. dos Santos * Instituto de Fisica -- UFRGS Av. Bento Gonc; accepted 20 October 1997 Abstract We report on the effects of Ar irradiation on a plasma-nitrided steel. Samples of AISI 1010 steel were nitrided in a mixture of H 2 -20% N 2 under a total pressure of 5 mbar

dos Santos, C.A.

247

Excitons in Boron Nitride Nanotubes: Dimensionality Effects Ludger Wirtz,1,2  

E-Print Network [OSTI]

Excitons in Boron Nitride Nanotubes: Dimensionality Effects Ludger Wirtz,1,2 Andrea Marini,3; published 30 March 2006) We show that the optical absorption spectra of boron nitride (BN) nanotubes are dominated by strongly bound excitons. Our first-principles calculations indicate that the binding energy

Marini, Andrea

248

MOVPE growth of semipolar III-nitride semiconductors on CVD graphene Priti Gupta n  

E-Print Network [OSTI]

MOVPE growth of semipolar III-nitride semiconductors on CVD graphene Priti Gupta n , A.A. Rahman pressure metalorganic vapor phase epitaxy B1. Graphene B1. Nitrides B2. Semiconducting III­V materials a b on graphene grown by chemical vapour deposition. GaN, AlGaN alloys, and InN layers are grown using an Al

Deshmukh, Mandar M.

249

The effect of surface mechanical attrition treatment on low temperature plasma nitriding of an austenitic stainless  

E-Print Network [OSTI]

of an austenitic stainless steel M. Chemkhi1 , D. Retraint1,* , A. Roos1 , C. Garnier1 , L. Waltz2 , C. Demangel3) followed by plasma nitriding on the mechanical properties of a medical grade austenitic stainless steel, nanocrystalline materials, plasma nitriding, austenitic steels 1. Introduction Austenitic stainless steel AISI 316

Boyer, Edmond

250

Microwave Nitridation of Sintered Reaction Bonded Silicon Parts for Natural Gas Fueled Diesel Engines  

SciTech Connect (OSTI)

This cooperative project was a joint development program between Eaton Corporation and Lockheed Martin Energy Research (LMER). Cooperative work was of benefit to both parties. ORNL was able to assess up-scale of the microwave nitridation process using a more intricate-shaped part designed for application in advanced diesel engines. Eaton Corporation mined access to microwave facilities and expertise for the nitridation of SRBSN materials. The broad objective of the CRADA established with Eaton Corporation and ORNL was to develop cost-effective silicon nitride ceramics compared to the current materials available. The following conclusions can be made from the work performed under the CRADA: (1) Demonstrated that the binder burnout step can be incorporated into the SRBSN processing in the microwave furnace. (2) Scale-up of the microwave nitridation process using Eaton Corporation parts showed that the nitridation weight gains were essentially identical to those obtained by conventional heating. (3) Combined nitridation and sintering processes using silicon nitride beads as packing powders results in degradation of the mechanical properties. (4) Gelcasting of silicon nitride materials using Eaton Si mixtures was demonstrated.

Edler, J.; Kiggans, J.O.; Suman, A.W.; Tiegs, T.N.

1999-01-01T23:59:59.000Z

251

Alternated high-and low-pressure nitriding of austenitic stainless steel: Mechanisms and results  

E-Print Network [OSTI]

Alternated high- and low-pressure nitriding of austenitic stainless steel: Mechanisms and results G a gas mixture of (N2 /H2):(50/50) in pressure, was applied to stainless-steel AISI 304. In the first or plasma nitriding of metal parts, in par- ticular those made of steel and cast iron, is extensively ap

252

Tunneling characteristics in chemical vapor deposited graphene hexagonal boron nitride graphene junctions  

E-Print Network [OSTI]

1 Tunneling characteristics in chemical vapor deposited graphene ­ hexagonal boron nitride ­ graphene junctions T. Roy1 , L. Liu2 , S. de la Barrera,3 B. Chakrabarti1,4 , Z. R. Hesabi1 , C. A. Joiner1 Abstract: Large area chemical vapor deposited graphene and hexagonal boron nitride was used to fabricate

Feenstra, Randall

253

One step process for producing dense aluminum nitride and composites thereof  

DOE Patents [OSTI]

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.

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

1989-01-01T23:59:59.000Z

254

Thermo-chemical Modelling of Uranium-free Nitride Fuels Mikael JOLKKONEN1;;y  

E-Print Network [OSTI]

and accepted December 22, 2003) A production process for americium-bearing, uranium-free nitride fuels environments was also estimated. We show that sintering of nitride compounds containing americium should be performed under nitrogen atmosphere in order to the avoid the excessive losses of americium reported from

Haviland, David

255

carbides. The multiphase/polytypic region can be expected to occur also in the nitrides because  

E-Print Network [OSTI]

in valence electron concentration where sev- eral phases of the 3d, 4d, and 5d transition metal carbides have, Transition Metal Carbides and Nitrides (Academic Press, New York, 1971). 6. C. Maerky, M.-O. Guillou, J. L is predicted to be substantially enhanced over that of traditional transition metal car- bide/nitride coatings

Shen, Guoyin

256

Single-Crystalline Mesoporous Molybdenum Nitride Nanowires with Improved Electrochemical Properties  

E-Print Network [OSTI]

process. I. Introduction TRANSITION -metal oxides, carbides, sulfides, and nitrides are extensively, and catalytic properties.1­4 Among the transition-metal com- pounds, transition-metal nitrides are regarded using transition-metal complex materials.16 However, the transi- tion-metal complex materials are lower

Cao, Guozhong

257

Hard superconducting nitrides Xiao-Jia Chen*, Viktor V. Struzhkin*, Zhigang Wu*, Maddury Somayazulu  

E-Print Network [OSTI]

(4). The refractory characteristics of these transition- metal nitrides and carbides have been, and hardness of selected superconducting transition-metal nitrides reveals inter- esting correlations among transition temperature (Tc) near 4 K when doped with boron (3). However, the transition-metal compounds

Wu, Zhigang

258

Large-scale well aligned carbon nitride nanotube films: Low temperature growth and electron field emission  

E-Print Network [OSTI]

Large-scale well aligned carbon nitride nanotube films: Low temperature growth and electron field emission Dingyong Zhong, Shuang Liu, Guangyu Zhang, and E. G. Wanga) State Key Laboratory for Surface Received 2 January 2001; accepted for publication 13 March 2001 Large-scale well aligned carbon nitride

Zhang, Guangyu

259

Anionic Gallium-Based Metal;#8722;Organic Framework and Its Sorption and Ion-Exchange Properties  

SciTech Connect (OSTI)

A gallium-based metal-organic framework Ga{sub 6}(C{sub 9}H{sub 3}O{sub 6}){sub 8} {center_dot} (C{sub 2}H{sub 8}N){sub 6}(C{sub 3}H{sub 7}NO){sub 3}(H{sub 2}O){sub 26} [1, Ga{sub 6}(1,3,5-BTC){sub 8} {center_dot} 6DMA {center_dot} 3DMF {center_dot} 26H{sub 2}O], GaMOF-1; BTC = benzenetricarboxylate/trimesic acid and DMA = dimethylamine, with space group I{bar 4}3d, a = 19.611(1) {angstrom}, and V = 7953.4(6) {angstrom}{sup 3}, was synthesized using solvothermal techniques and characterized by synchrotron-based X-ray microcrystal diffraction. Compound 1 contains isolated gallium tetrahedra connected by the organic linker (BTC) forming a 3,4-connected anionic porous network. Disordered positively charged ions and solvent molecules are present in the pore, compensating for the negative charge of the framework. These positively charged molecules could be exchanged with alkali-metal ions, as is evident by an ICP-MS study. The H{sub 2} storage capacity of the parent framework is moderate with a H{sub 2} storage capacity of {approx}0.5 wt % at 77 K and 1 atm.

Banerjee, Debasis; Kim, Sun Jin; Wu, Haohan; Xu, Wenqian; Borkowski, Lauren A.; Li, Jing; Parise, John B. (Kwangju); (Rutgers); (SBU)

2012-04-30T23:59:59.000Z

260

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

SciTech Connect (OSTI)

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.

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

2008-04-15T23:59:59.000Z

Note: This page contains sample records for the topic "bulk gallium nitride" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

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

DOE Patents [OSTI]

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.

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

2010-11-09T23:59:59.000Z

262

Microfabricated bulk wave acoustic bandgap device  

DOE Patents [OSTI]

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).

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

2010-06-08T23:59:59.000Z

263

Microfabricated bulk wave acoustic bandgap device  

DOE Patents [OSTI]

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).

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)

2010-11-23T23:59:59.000Z

264

A Bulk Parameterization of Giant CCN  

E-Print Network [OSTI]

), growth by condensation, and growth by coalescence (Beard and Ochs 1993). The long time scale required for conden- sational growth of droplets large enough for collection efficiencies to become significant has been a subject of ongoing investigation.... Bulk microphysical parameterizations traditionally partition the total liquid water into two categories, cloud and rainwater, based on a threshold radius of 20–25 #2;m. The most important effect of GCCN is through their impact on precipitation...

Mechem, David B.; Kogan, Yefim L.

2008-07-01T23:59:59.000Z

265

Simulation assisted design of a gallium phosphide np photovoltaic junction Charles R. Allen, Jong-Hyeok Jeon , Jerry M. Woodall  

E-Print Network [OSTI]

University, 1205 W State Street, West Lafayette, IN, USA a r t i c l e i n f o Article history: Received 27 February 2010 Keywords: Gallium phosphide Solar cell Multi-junction CPV Simulation a b s t r a c with measurements of the dark and light response. The light current was measured under an illumination of air mass

Woodall, Jerry M.

266

Formation of etch pits during carbon doping of gallium arsenide with carbon tetrachloride by metalorganic vapor-phase epitaxy  

E-Print Network [OSTI]

Formation of etch pits during carbon doping of gallium arsenide with carbon tetrachloride to examine the effects of carbon tetrachloride concentration and temperature on the morphology of carbon with increasing carbon tetrachloride concentration. Step bunching and pinning was observed at a IV/III ratio

Li, Lian

267

Hydrogen isotope separation utilizing bulk getters  

DOE Patents [OSTI]

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.

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

1991-01-01T23:59:59.000Z

268

Hydrogen isotope separation utilizing bulk getters  

DOE Patents [OSTI]

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.

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

1990-01-01T23:59:59.000Z

269

Hydrogen isotope separation utilizing bulk getters  

DOE Patents [OSTI]

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.

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

1991-08-20T23:59:59.000Z

270

Formation of Nickel Silicide from Direct-liquid-injection Chemical-vapor-deposited Nickel Nitride Films  

SciTech Connect (OSTI)

Smooth, continuous, and highly conformal nickel nitride (NiN{sub x}) films were deposited by direct liquid injection (DLI)-chemical vapor deposition (CVD) using a solution of bis(N,N{prime}-di-tert-butylacetamidinato)nickel(II) in tetrahydronaphthalene as the nickel (Ni) source and ammonia (NH{sub 3}) as the coreactant gas. The DLI-CVD NiNx films grown on HF-last (100) silicon and on highly doped polysilicon substrates served as the intermediate for subsequent conversion into nickel silicide (NiSi), which is a key material for source, drain, and gate contacts in microelectronic devices. Rapid thermal annealing in the forming gas of DLI-CVD NiNx films formed continuous NiSi films at temperatures above 400 C. The resistivity of the NiSi films was 15{mu}{Omega} cm, close to the value for bulk crystals. The NiSi films have remarkably smooth and sharp interfaces with underlying Si substrates, thereby producing contacts for transistors with a higher drive current and a lower junction leakage. Resistivity and synchrotron X-ray diffraction in real-time during annealing of NiNx films showed the formation of a NiSi film at about 440 C, which is morphologically stable up to about 650 C. These NiSi films could find applications in future nanoscale complementary metal oxide semiconductor devices or three-dimensional metal-oxide-semiconductor devices such as Fin-type field effect transistors for the 22 nm technology node and beyond.

Li, Z.; Gordon, R; Li, H; Shenai, D; Lavoie, C

2010-01-01T23:59:59.000Z

271

Synthesis of silicon nitride particles in pulsed Rf plasmas  

SciTech Connect (OSTI)

Silicon nitride (hydrogenated) particles are synthesized using a pulsed 13.56 Mhz glow discharge. The plasma is modulated with a square-wave on/off cycle of varying period to study the growth kinetics. In situ laser light scattering and ex situ particle analysis are used to study the nucleation and growth. For SiH{sub 4}/Ar and SiH{sub 4}/NH{sub 3} plasmas, an initial very rapid growth phase is followed by slower growth, approaching the rate of thin film deposition on adjacent flat surfaces. The average particle size can be controlled in the 10-100 nm range by adjusting the plasma-on time. The size dispersion of the particles is large and is consistent with a process of continuous nucleation during the plasma-on period. The large polydispersity is also reported for silicon particles from silane and differs from that reported in other laboratories. The silicon nitride particle morphology is compared to that of silicon and silicon carbide particles generated by the same technique. Whereas Si particles appear as rough clusters of smaller subunits, the SiC particles are smooth spheres, and the Si{sub 3}N{sub 4} particles are smooth but non-spherical. Post-plasma oxidation kinetics of the particles are studied with FTIR and are consistent with a hydrolysis mechanism proposed in earlier work with continuous plasmas. Heat treatment of the powder in an ammonia atmosphere results in the elimination of hydrogen, rendering the silicon nitride resistant to atmospheric oxidation.

Buss, R.J.; Babu, S.V.

1995-11-01T23:59:59.000Z

272

Nanostructured High-Temperature Bulk Thermoelectric Energy Conversion...  

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

More Documents & Publications Nanostructured High-Temperature Bulk Thermoelectric Energy Conversion for Efficient Automotive Waste Heat Recovery Vehicle Technologies Office...

273

Boron nitride nanosheets as oxygen-atom corrosion protective coatings  

SciTech Connect (OSTI)

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.

Yi, Min [Beijing Key Laboratory for Powder Technology Research and Development, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Plasma Laboratory, Ministry-of-Education Key Laboratory of Fluid Mechanics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Shen, Zhigang, E-mail: shenzhg@buaa.edu.cn [Beijing Key Laboratory for Powder Technology Research and Development, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Plasma Laboratory, Ministry-of-Education Key Laboratory of Fluid Mechanics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); School of Material Science and Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Zhao, Xiaohu [Plasma Laboratory, Ministry-of-Education Key Laboratory of Fluid Mechanics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Liang, Shuaishuai [Beijing Key Laboratory for Powder Technology Research and Development, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Liu, Lei [Beijing Key Laboratory for Powder Technology Research and Development, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); School of Material Science and Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China)

2014-04-07T23:59:59.000Z

274

Excellent oxidation endurance of boron nitride nanotube field electron emitters  

SciTech Connect (OSTI)

Boron nitride nanotubes (BNNTs) are considered as a promising cold electron emission material owing to their negative electron affinity. BNNT field emitters show excellent oxidation endurance after high temperature thermal annealing of 600?°C in air ambient. There is no damage to the BNNTs after thermal annealing at a temperature of 600?°C and also no degradation of field emission properties. The thermally annealed BNNTs exhibit a high maximum emission current density of 8.39?mA/cm{sup 2} and show very robust emission stability. The BNNTs can be a promising emitter material for field emission devices under harsh oxygen environments.

Song, Yenan [Department of Micro/Nano Systems, Korea University, Seoul 136-713 (Korea, Republic of); Sun, Yuning; Hoon Shin, Dong; Nam Yun, Ki [School of Electrical Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Song, Yoon-Ho [Nano Electron-Source Creative Research Center, Creative and Challenging Research Division, ETRI, Daejeon 305-700 (Korea, Republic of); Milne, William I. [Electrical Engineering Division, Engineering Department, Cambridge University, Cambridge CB3 0FA (United Kingdom); Jin Lee, Cheol, E-mail: cjlee@korea.ac.kr [Department of Micro/Nano Systems, Korea University, Seoul 136-713 (Korea, Republic of); School of Electrical Engineering, Korea University, Seoul 136-713 (Korea, Republic of)

2014-04-21T23:59:59.000Z

275

Method of nitriding niobium to form a superconducting surface  

DOE Patents [OSTI]

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.

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

2014-08-19T23:59:59.000Z

276

Aluminum nitride nanophotonic circuits operating at ultraviolet wavelengths  

SciTech Connect (OSTI)

Aluminum nitride (AlN) has recently emerged as a promising material for integrated photonics due to a large bandgap and attractive optical properties. Exploiting the wideband transparency, we demonstrate waveguiding in AlN-on-Insulator circuits from near-infrared to ultraviolet wavelengths using nanophotonic components with dimensions down to 40?nm. By measuring the propagation loss over a wide spectral range, we conclude that both scattering and absorption of AlN-intrinsic defects contribute to strong attenuation at short wavelengths, thus providing guidelines for future improvements in thin-film deposition and circuit fabrication.

Stegmaier, M.; Ebert, J.; Pernice, W. H. P., E-mail: wolfram.pernice@kit.edu [Institute of Nanotechnology, Karlsruhe Institute of Technology, 76133 Karlsruhe (Germany); Meckbach, J. M.; Ilin, K.; Siegel, M. [Institute of Micro- und Nanoelectronic Systems, Karlsruhe Institute of Technology, 76187 Karlsruhe (Germany)

2014-03-03T23:59:59.000Z

277

Field emission characteristics from graphene on hexagonal boron nitride  

SciTech Connect (OSTI)

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.

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)

2014-06-02T23:59:59.000Z

278

The Economic Case for Bulk Energy Storage in Transmission Systems  

E-Print Network [OSTI]

The Economic Case for Bulk Energy Storage in Transmission Systems with High Percentages to Engineer the Future Electric Energy System #12;#12;The Economic Case for Bulk Energy Storage Economic Case for Bulk Energy Storage in Transmission Sys- tems with High Percentages of Renewable

279

Towards bulk based preconditioning for quantum dotcomputations  

SciTech Connect (OSTI)

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.

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

2006-05-25T23:59:59.000Z

280

Role of bulk energy in nuclear multifragmentation  

SciTech Connect (OSTI)

Because of thermal expansion and residual interactions, hot nuclear fragments produced in multifragmentation reactions may have nucleon density lower than the equilibrium density of cold nuclei. In terms of a liquid-drop model this effect can be taken into account by reducing the bulk energy of fragments. We study the influence of this change on fragment yields and isotope distributions within the framework of the statistical multifragmentation model. Similarities and differences with previously discussed modifications of symmetry and surface energies of nuclei are analyzed.

Buyukcizmeci, N.; Ogul, R. [Department of Physics, University of Selcuk, 42079 Konya (Turkey); Botvina, A. S. [Institute for Nuclear Research, Russian Academy of Sciences, RU-117312 Moscow (Russian Federation); Frankfurt Institute for Advanced Studies, J. W. Goethe University, D-60438 Frankfurt am Main (Germany); Mishustin, I. N. [Frankfurt Institute for Advanced Studies, J. W. Goethe University, D-60438 Frankfurt am Main (Germany); Kurchatov Institute, Russian Research Center, RU-123182 Moscow (Russian Federation)

2008-03-15T23:59:59.000Z

Note: This page contains sample records for the topic "bulk gallium nitride" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Active neutron multiplicity counting of bulk uranium  

SciTech Connect (OSTI)

This paper describes a new nondestructive assay technique being developed to assay bulk uranium containing kilogram quantities of {sup 235}U. The new technique uses neutron multiplicity analysis of data collected with a coincidence counter outfitted with AmLi neutron sources. We have calculated the expected neutron multiplicity count rate and assay precision for this technique and will report on its expected performance as a function of detector design characteristics, {sup 235 }U sample mass, AmLi source strength, and source-to-sample coupling. 11 refs., 2 figs., 2 tabs.

Ensslin, N.; Krick, M.S.; Langner, D.G.; Miller, M.C.

1991-01-01T23:59:59.000Z

282

Local environment and composition of magnesium gallium layered double hydroxides determined from solid-state 1H and 71Ga NMR spectroscopy  

SciTech Connect (OSTI)

Ordering of gallium(III) in a series of magnesium gallium layered double hydroxides (LDH’s), [Mg1-xGax(OH)2(NO3)x yH2O], was determined using solid-state 1H and 71Ga NMR spectroscopy. Depletion of Ga in these LDH’s is demonstrated to be the result of soluble [Ga(OH)4]-complexes formed during synthesis.

Petersen, Line B.; Lipton, Andrew S.; Zorin, Vadim; Nielsen, Ulla Gro

2014-11-01T23:59:59.000Z

283

Nitride and Oxynitride Based Phosphors for Solid State Lighting  

SciTech Connect (OSTI)

The objective of the project is to advance the technology of the Lightscape Materials Inc. (Lightscape) proprietary nitride and oxynitride phosphors for solid state lighting (SSL) from the current level of maturity of applied research to advanced engineering development. This objective will be accomplished by optimizing the novel nitride and oxynitride phosphors, whose formulations are listed in Table 1, and establishing cost-effective preparation processes for the phosphors. The target performances of the phosphors are: • High luminescence efficiency: Quantum Yield = 90%. • Superior thermal stability of luminescence: Thermal Quenching Loss <10% at 150 °C. • Superior environmental stability: Luminescence Maintenance >90% after 5,000 hours at 85 °C and 85% relative humidity. • Scattering loss <10%. • Cost-effective preparation processes. The resulting phosphor materials and their preparation processes are anticipated to be a drop-in component for product development paths undertaken by LED lamp makers in the SSL industry. Upon program completion, Lightscape will target market insertion that enables high efficacy, high color rendering index (CRI), high thermal stability and long lifetime LED-based lighting products for general illumination that realizes substantial energy savings.

Tian, Yongchi

2011-10-15T23:59:59.000Z

284

High upper critical field in disordered niobium nitride superconductor  

SciTech Connect (OSTI)

Superconducting Niobium Nitride thin films have been deposited on glass, aluminum nitride buffered glass, and oxidized silicon substrates by reactive DC magnetron sputtering at ambient substrate temperatures. The crystal structure of these thin films has been determined to be cubic fcc B1 structure by Glancing Incidence X-Ray Diffraction analysis. The superconducting transition temperatures of the thin films were measured to be greater than 11.6?K with a maximum of 13.4?K. The negative temperature coefficient of resistance observed in these thin films indicates the presence of disorder. Magneto-resistance measurements have been carried out on these thin films patterned into standard four probe geometry upto a maximum magnetic field of 12?T for two films and upto 15?T for the other two films. The dependence of transition temperature on the applied field is analyzed to estimate the upper critical field. The upper critical field for most of the films was estimated to exceed 35?T, while one of the most disordered films had an estimated upper critical field greater than 70?T.

Baskaran, R., E-mail: baskaran@igcar.gov.in; Thanikai Arasu, A. V.; Amaladass, E. P.; Janawadkar, M. P. [Materials Science Group, IGCAR, Kalpakkam-603102 (India)

2014-10-28T23:59:59.000Z

285

Catalytic and physicochemical properties of aluminoplatinum catalysts modified with indium and gallium  

SciTech Connect (OSTI)

Aluminoplatinum catalysts (APC) are widely used in transformations of hydrocarbons, particularly in reforming of gasoline fractions and dehydrogenation of higher normal paraffins. Promotion of APC with indium and gallium increases their activity and stability in the dehydrogenation of paraffins. Introduction of group III elements in APC inhibits coke formation during dehydrogenation and prevents blocking of the surface of the Pt. The change in the catalytic properties of APC modified with In is due to the partial transfer of the electron density from Pt to In. Both APC with In and Ga additives and monometallic catalysts were studied in the present article by the methods of IR spectroscopy and adsorption. In addition to traditional transmission IR spectroscopy, IR spectroscopy in diffusely scattered light was used, which permits conducting both spectral and adsorption measurements on the same samples.

Zaitsev, A.V.; Tyupaev, A.P.; Borovkov, V.Yu.; Timofeeva, E.A.; Isatulyants, G.V.; Kazanskii, B.B.

1986-10-10T23:59:59.000Z

286

The status of the solar neutrino problem and the Russian-American gallium experiment (SAGE)  

SciTech Connect (OSTI)

Perhaps the most outstanding discrepancy between prediction and measurements in current particle physics comes from the solar neutrino problem, in which a large deficit of high-energy solar neutrinos is observed. Many Nonstandard Solar Models have been invoked to try to reduce the predicted flux, but all have run into problems in trying to reproduce other measured parameters (e.g., the luminosity) of the Sun. Other explanations involving new physics such as neutrino decay and neutrino oscillations, etc. have also been proffered. Again, most of these explanations have been ruled out by either laboratory or astrophysical measurements. It appears that perhaps the most likely particle physics solution is that of matter enhanced neutrino oscillation, the Mikheyev-Smirnov-Wolfenstein (MSW) oscillations. Two new radiochemical gallium experiments, which have a low enough threshold to be sensitive to the dominant flux of low-energy p-p neutrinos, now also report a deficit and also favor a particle physics solution.

Bowles, T.J.

1994-04-01T23:59:59.000Z

287

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

SciTech Connect (OSTI)

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.

Sallis, S.; Williams, D. S. [Materials Science and Engineering, Binghamton University, Binghamton, New York 13902 (United States); Butler, K. T.; Walsh, A. [Center for Sustainable Technologies and Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom); Quackenbush, N. F. [Department of Physics, Applied Physics, and Astronomy, Binghamton University, Binghamton, New York 13902 (United States); Junda, M.; Podraza, N. J. [Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606 (United States); Fischer, D. A.; Woicik, J. C. [Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); White, B. E.; Piper, L. F. J., E-mail: lpiper@binghamton.edu [Department of Physics, Applied Physics, and Astronomy, Binghamton University, Binghamton, New York 13902 (United States); Materials Science and Engineering, Binghamton University, Binghamton, New York 13902 (United States)

2014-06-09T23:59:59.000Z

288

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

SciTech Connect (OSTI)

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.

Muhammad, R.; Ahamad, R. [Sustainability Research Alliance, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Ibrahim, Z.; Othaman, Z. [Physic Department, Faculty of Science, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia)

2014-03-05T23:59:59.000Z

289

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

SciTech Connect (OSTI)

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.

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

2013-06-01T23:59:59.000Z

290

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

SciTech Connect (OSTI)

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.

Salinger, A.G.; Shadid, J.N.; Hutchinson, S.A. [and others

1998-01-01T23:59:59.000Z

291

Tunneling characteristics in chemical vapor deposited graphene–hexagonal boron nitride–graphene junctions  

SciTech Connect (OSTI)

Large area chemical vapor deposited graphene and hexagonal boron nitride was used to fabricate graphene–hexagonal boron nitride–graphene symmetric field effect transistors. Gate control of the tunneling characteristics is observed similar to previously reported results for exfoliated graphene–hexagonal boron nitride–graphene 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.

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)

2014-03-24T23:59:59.000Z

292

Optoelectronic Properties in Monolayers of Hybridized Graphene and Hexagonal Boron Nitride  

E-Print Network [OSTI]

We explain the nature of the electronic energy gap and optical absorption spectrum of carbon–boron-nitride (CBN) monolayers using density functional theory, GW and Bethe-Salpeter calculations. The band structure and the ...

Bernardi, Marco

293

E-Print Network 3.0 - argon nitrides Sample Search Results  

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

I?MAYR Sti+ng Institutfur Werkstofiechnik... ,Badgasteiner Str: 3, 2800Bremen 33, Germany Abstract Aluminium nitride (AlN) is a ve interestin ceramic because... the use %of...

294

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

DOE Patents [OSTI]

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.

Maya, Leon (Oak Ridge, TN)

1988-05-24T23:59:59.000Z

295

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

DOE Patents [OSTI]

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.

Maya, Leon (Oak Ridge, TN)

1991-01-01T23:59:59.000Z

296

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

DOE Patents [OSTI]

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.

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

1992-10-13T23:59:59.000Z

297

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

DOE Patents [OSTI]

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.

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

1992-01-01T23:59:59.000Z

298

Electronic structure analyses and activation studies of a dinitrogen-derived terminal nitride of molybdenum  

E-Print Network [OSTI]

Chapter 1: Complexes obtained by electrophilic attack on a dinitrogen-derived terminal molybdenum nitride: Electronic structure analysis by solid state CP/MAS ¹?N NMR in combination ... Chapter 2. Carbene chemistry in the ...

Sceats, Emma Louise, 1978-

2004-01-01T23:59:59.000Z

299

Photon-induced tunneling in graphene-boron nitride-graphene heterostructures  

E-Print Network [OSTI]

Graphene is a material that has generated much interest due to its many unique electronic and optical properties. In this work, we present optoelectronic measurements performed on ultrathin graphene-boron nitride-graphene ...

Nair, Nityan

2013-01-01T23:59:59.000Z

300

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

DOE Patents [OSTI]

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.

McCoy, Lowell R. (Woodland Hills, CA)

1982-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "bulk gallium nitride" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

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

DOE Patents [OSTI]

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.

McCoy, L.R.

1981-01-23T23:59:59.000Z

302

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

DOE Patents [OSTI]

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.

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

2011-03-29T23:59:59.000Z

303

Organic hybrid planar-nanocrystalline bulk heterojunctions  

DOE Patents [OSTI]

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.

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

2011-03-01T23:59:59.000Z

304

Organic hybrid planar-nanocrystalline bulk heterojunctions  

DOE Patents [OSTI]

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.

Forrest, Stephen R.; Yang, Fan

2013-04-09T23:59:59.000Z

305

DEVELOPMENT OF THE BULK TRITIUM SHIPPING PACKAGING  

SciTech Connect (OSTI)

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.

Blanton, P.; Eberl, K.

2008-09-14T23:59:59.000Z

306

DEPLOYMENT OF THE BULK TRITIUM SHIPPING PACKAGE  

SciTech Connect (OSTI)

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.

Blanton, P.

2013-10-10T23:59:59.000Z

307

Rotary adsorbers for continuous bulk separations  

DOE Patents [OSTI]

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.

Baker, Frederick S. (Oak Ridge, TN)

2011-11-08T23:59:59.000Z

308

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

DOE Patents [OSTI]

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.

Bhattacharya, Raghu N. (Littleton, CO); Hasoon, Falah S. (Arvada, CO); Wiesner, Holm (Golden, CO); Keane, James (Lakewood, CO); Noufi, Rommel (Golden, CO); Ramanathan, Kannan (Golden, CO)

1999-02-16T23:59:59.000Z

309

Impurity-induced disorder in III-nitride materials and devices  

DOE Patents [OSTI]

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.

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

2014-11-25T23:59:59.000Z

310

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

DOE Patents [OSTI]

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.

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

2011-06-28T23:59:59.000Z

311

High temperature mechanical performance of a hot isostatically pressed silicon nitride  

SciTech Connect (OSTI)

Silicon nitride ceramics are an attractive material of choice for designers and manufacturers of advanced gas turbine engine components for many reasons. These materials typically have potentially high temperatures of usefulness (up to 1400{degrees}C), are chemically inert, have a relatively low specific gravity (important for inertial effects), and are good thermal conductors (i.e., resistant to thermal shock). In order for manufacturers to take advantage of these inherent properties of silicon nitride, the high-temperature mechanical performance of the material must first be characterized. The mechanical response of silicon nitride to static, dynamic, and cyclic conditions at elevated temperatures, along with reliable and representative data, is critical information that gas turbine engine designers and manufacturers require for the confident insertion of silicon nitride components into gas turbine engines. This final report describes the high-temperature mechanical characterization and analyses that were conducted on a candidate structural silicon nitride ceramic. The high-temperature strength, static fatigue (creep rupture), and dynamic and cyclic fatigue performance were characterized. The efforts put forth were part of Work Breakdown Structure Subelement 3.2.1, {open_quotes}Rotor Data Base Generation.{close_quotes} PY6 is comparable to other hot isostatically pressed (HIPed) silicon nitrides currently being considered for advanced gas turbine engine applications.

Wereszczak, A.A.; Ferber, M.K.; Jenkins, M.G.; Lin, C.K.J. [and others] [and others

1996-01-01T23:59:59.000Z

312

Single-layer graphene on silicon nitride micromembrane resonators  

SciTech Connect (OSTI)

Due to their low mass, high quality factor, and good optical properties, silicon nitride (SiN) micromembrane resonators are widely used in force and mass sensing applications, particularly in optomechanics. The metallization of such membranes would enable an electronic integration with the prospect for exciting new devices, such as optoelectromechanical transducers. Here, we add a single-layer graphene on SiN micromembranes and compare electromechanical coupling and mechanical properties to bare dielectric membranes and to membranes metallized with an aluminium layer. The electrostatic coupling of graphene covered membranes is found to be equal to a perfectly conductive membrane, without significantly adding mass, decreasing the superior mechanical quality factor or affecting the optical properties of pure SiN micromembranes. The concept of graphene-SiN resonators allows a broad range of new experiments both in applied physics and fundamental basic research, e.g., for the mechanical, electrical, or optical characterization of graphene.

Schmid, Silvan; Guillermo Villanueva, Luis; Amato, Bartolo; Boisen, Anja [Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech, Building 345 East, 2800 Kongens Lyngby (Denmark); Bagci, Tolga; Zeuthen, Emil; Sørensen, Anders S.; Usami, Koji; Polzik, Eugene S. [QUANTOP, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen (Denmark); Taylor, Jacob M. [Joint Quantum Institute/NIST, College Park, Maryland 20899 (United States); Herring, Patrick K.; Cassidy, Maja C. [School of Engineering and Applied Science, Harvard University, Cambridge, Massachusetts 02138 (United States); Marcus, Charles M. [Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen (Denmark); Cheol Shin, Yong; Kong, Jing [Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2014-02-07T23:59:59.000Z

313

Role of defects in III-nitride based electronics  

SciTech Connect (OSTI)

The LDRD entitled ``Role of Defects in III-Nitride Based Devices'' is aimed to place Sandia National Laboratory at the forefront of the field of GaN materials and devices by establishing a scientific foundation in areas such as material growth, defect characterization/modeling, and processing (metalization and etching) chemistry. In this SAND report the authors summarize their studies such as (1) the MOCVD growth and doping of GaN and AlGaN, (2) the characterization and modeling of hydrogen in GaN, including its bonding, diffusion, and activation behaviors, (3) the calculation of energetic of various defects including planar stacking faults, threading dislocations, and point defects in GaN, and (4) dry etching (plasma etching) of GaN (n- and p-types) and AlGaN. The result of the first AlGaN/GaN heterojunction bipolar transistor is also presented.

HAN,JUNG; MYERS JR.,SAMUEL M.; FOLLSTAEDT,DAVID M.; WRIGHT,ALAN F.; CRAWFORD,MARY H.; LEE,STEPHEN R.; SEAGER,CARLETON H.; SHUL,RANDY J.; BACA,ALBERT G.

2000-01-01T23:59:59.000Z

314

Silver delafossite nitride, AgTaN{sub 2}?  

SciTech Connect (OSTI)

A new silver nitride, AgTaN{sub 2}, was synthesized from NaTaN{sub 2} by a cation-exchange reaction, using a AgNO{sub 3}-NH{sub 4}NO{sub 3} flux at 175 {sup o}C. Its crystal structure type is delafossite (R3-bar m) with hexagonal lattice parameters of a=3.141(3) A, c=18.81(2) A, in which silver is linearly coordinated to nitrogen. Energy dispersive X-ray analysis and combustion nitrogen/oxygen analysis gave a composition with atomic ratios of Ag:Ta:N:O as 1.0:1.2(1):2.1(1):0.77(4), which is somewhat Ta rich and indicates some oxide formation. The X-ray photoelectron spectroscopy analysis showed a Ta- and O-rich surface and transmission electron microscope observation exhibited aggregates of ca. 4-5 nm-sized particles on the surface, which are probably related to the composition deviation from a AgTaN{sub 2}. The lattice parameters of stoichiometric AgTaN{sub 2} calculated by density functional theory agree with the experimental ones, but the possibility of some oxygen incorporation and/or silver deficiency is not precluded. -- Graphical abstract: A delafossite silver nitride, AgTaN{sub 2}, was synthesized from NaTaN{sub 2} by a cation-exchange reaction using a AgNO{sub 3}-NH{sub 4}NO{sub 3} flux. It contains N-Ag-N linear bonding. Display Omitted

Miura, Akira [Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen (Germany); Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853 (United States); Lowe, Michael; Leonard, Brian M.; Subban, Chinmayee V. [Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853 (United States); Masubuchi, Yuji; Kikkawa, Shinichi [Graduate School of Engineering, Hokkaido University, N13W8, Kita-ku Sapporo 060-8628 (Japan); Dronskowski, Richard [Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen (Germany); Hennig, Richard G. [Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853 (United States); Abruna, Hector D. [Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853 (United States); DiSalvo, Francis J., E-mail: fjd3@cornell.ed [Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853 (United States)

2011-01-15T23:59:59.000Z

315

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

316

New nano structure approaches for bulk thermoelectric materials  

E-Print Network [OSTI]

in bulk thermoelectric materials", M. Mater. Res. Soc.Thermoelectricity", Materials Reserach Society Symposium,Johnson, D. C. , Eds. Materials Research Society: Boston,

Kim, Jeonghoon

2010-01-01T23:59:59.000Z

317

Regulatory Roadmap Workshop for Federal Bulk Transmission Regulations...  

Open Energy Info (EERE)

Regulatory Roadmapping Pgower's picture Submitted by Pgower(45) Member 7 August, 2014 - 13:19 One-day workshop to review regulatory roadmaps for bulk transmission. Date:...

318

Bulk Hydrogen Storage - Strategic Directions for Hydrogen Delivery...  

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

Breakout Session - Bulk Hydrogen Storage RD&D Needs Top 6 Categories: Advanced Concepts Advanced Materials Codes & Standards Studies & Analyses Tools & Techniques Demonstration &...

319

Optimization Online - Real-Time Dispatchability of Bulk Power ...  

E-Print Network [OSTI]

Mar 16, 2015 ... Real-Time Dispatchability of Bulk Power Systems with Volatile Renewable Generations. Wei Wei (wei-wei04 ***at*** mails.tsinghua.edu.cn)

Wei Wei

2015-03-16T23:59:59.000Z

320

Biofuels production from hydrotreating of vegetable oil using supported noble metals, and transition metal carbide and nitride.  

E-Print Network [OSTI]

?? The focus of this research is to prepare non-sulfided hydrotreating catalysts, supported noble metal and transition metal carbide/ nitride, and evaluate their hydrocracking activities… (more)

Wang, Huali

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "bulk gallium nitride" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Material Profile Influences in Bulk-Heterojunctions  

SciTech Connect (OSTI)

he morphology in mixed bulk-heterojunction films are compared using three different quantitative measurement techniques. We compare the vertical composition changes using high-angle annular dark-field scanning transmission electron microscopy with electron tomography and neutron and x-ray reflectometry. The three measurement techniques yield qualita-tively comparable vertical concentration measurements. The presence of a metal cathode during thermal annealing is observed to alter the fullerene concentration throughout the thickness of the film for all measurements. However, the abso-lute vertical concentration of fullerene is quantitatively different for the three measurements. The origin of the quantitative measurement differences is discussed. The authors thank Luna Innovations, Inc. for donating the endohedral fullerenes used in this study and Plextronics for the P3HT. They are gratefully thank the National Science Foundation Energy for Sustainability Program, Award No. 0933435. This work benefited from the use of the Lujan Neutron Scattering Center at Los Alamos Neutron Science Center funded by the DOE Office of Basic Energy Sciences and Los Alamos National Laboratory under DOE Contract DE-AC52-06NA25396. This research was also supported in part by Laboratory Directed Research & Development program at PNNL. The Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy under contract DE-AC05-76RL01830.

Roehling, John D.; Rochester, Christopher W.; Ro, Hyun W.; Wang, Peng; Majewski, Jaroslaw; Batenburg, Kees J.; Arslan, Ilke; Delongchamp, Dean M.; Moule, Adam J.

2014-10-01T23:59:59.000Z

322

Improving Bulk Microphysics Parameterizations in Simulations of Aerosol Effects  

SciTech Connect (OSTI)

To improve the microphysical parameterizations for simulations of the aerosol indirect effect (AIE) in regional and global climate models, a double-moment bulk microphysical scheme presently implemented in the Weather Research and Forecasting (WRF) model is modified and the results are compared against atmospheric observations and simulations produced by a spectral bin microphysical scheme (SBM). Rather than using prescribed aerosols as in the original bulk scheme (Bulk-OR), a prognostic doublemoment aerosol representation is introduced to predict both the aerosol number concentration and mass mixing ratio (Bulk-2M). The impacts of the parameterizations of diffusional growth and autoconversion and the selection of the embryonic raindrop radius on the performance of the bulk microphysical scheme are also evaluated. Sensitivity modeling experiments are performed for two distinct cloud regimes, maritime warm stratocumulus clouds (SC) over southeast Pacific Ocean from the VOCALS project and continental deep convective clouds (DCC) in the southeast of China from the Department of Energy/ARM Mobile Facility (DOE/AMF) - China field campaign. The results from Bulk-2M exhibit a much better agreement in the cloud number concentration and effective droplet radius in both the SC and DCC cases with those from SBM and field measurements than those from Bulk-OR. In the SC case particularly, Bulk-2M reproduces the observed drizzle precipitation, which is largely inhibited in Bulk-OR. Bulk-2M predicts enhanced precipitation and invigorated convection with increased aerosol loading in the DCC case, consistent with the SBM simulation, while Bulk-OR predicts the opposite behaviors. Sensitivity experiments using four different types of autoconversion schemes reveal that the autoconversion parameterization is crucial in determining the raindrop number, mass concentration, and drizzle formation for warm 2 stratocumulus clouds. An embryonic raindrop size of 40 ?m is determined as a more realistic setting in the autoconversion parameterization. The saturation adjustment employed in calculating condensation/evaporation in the bulk scheme is identified as the main factor responsible for the large discrepancies in predicting cloud water in the SC case, suggesting that an explicit calculation of diffusion growth with predicted supersaturation is necessary for further improvements of the bulk microphysics scheme. Lastly, a larger rain evaporation rate below cloud is found in the bulk scheme in comparison to the SBM simulation, which could contribute to a lower surface precipitation in the bulk scheme.

Wang, Yuan; Fan, Jiwen; Zhang, Renyi; Leung, Lai-Yung R.; Franklin, Charmaine N.

2013-06-05T23:59:59.000Z

323

Applicability of carbon and boron nitride nanotubes as biosensors: Effect of biomolecular adsorption on the transport properties of carbon and boron  

E-Print Network [OSTI]

Applicability of carbon and boron nitride nanotubes as biosensors: Effect of biomolecular;Applicability of carbon and boron nitride nanotubes as biosensors: Effect of biomolecular adsorption University, Houghton, Michigan 49931, USA 2 US Army Research Laboratory, Weapons and Materials Research

Pandey, Ravi

324

Role of Cavitation in Bulk Ultrasound Ablation: A Histologic Study  

E-Print Network [OSTI]

Role of Cavitation in Bulk Ultrasound Ablation: A Histologic Study Chandra Priya Karunakaran, Mark of Cincinnati, Cincinnati, Ohio Abstract. The role of cavitation in bulk ultrasound ablation has been evaluated-ablate probe at 31 W/cm2 for 20 minutes under normal and elevated ambient pressures. A 1 MHz passive cavitation

Mast, T. Douglas

325

Crystal structure and electron microprobe analyses of a lanthanum lutetium gallium garnet  

SciTech Connect (OSTI)

Single-crystal electron microprobe analysis of a lanthanum lutetium gallium garnet has resulted in a composition of La{sub 2.37}Nd{sub 0.07}Pb{sub 0.01}Lu{sub 2.54}Cr{sub 0.01} Ga{sub 3.00}O{sub 12}. This composition gives better agreement between observed and calculated total dielectric polarizabilities than previously reported compositions (La{sub 2.26--2.32}Nd{sub 0.04}Lu{sub 2.57--2.63}Ga{sub 3.07}O{sub 12} by x-ray fluorescence and La{sub 2.655}Nd{sub 0.027}Lu{sub 2.656}Ga{sub 2.655}O{sub 12} by inductively coupled plasma analyses), and does not imply the crystal-chemically improbable presence of Lu{sup 3+} in the tetrahedral site. X-ray and neutron crystal-structure analyses have confirmed that little or no Lu resides in this site.

Parise, J.B.; Harlow, R.L.; Shannon, R.D. (Central Research and Development Department, E. I. DuPont De Nemours and Co., Experimental Station, Wilmington, Delaware 19880-0228 (United States)); Kwei, G.H. (LANSCE, MS-H805, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)); Allik, T.H. (Science Applications International Corporation, 1710 Goodridge Dr., P.O. Box 1303, McLean, Virginia 22102 (United States)); Armstrong, J.T. (Department of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125 (United States))

1992-09-15T23:59:59.000Z

326

Electronic passivation of silicon surfaces by thin films of atomic layer deposited gallium oxide  

SciTech Connect (OSTI)

This paper proposes the application of gallium oxide (Ga{sub 2}O{sub 3}) thin films to crystalline silicon solar cells. Effective passivation of n- and p-type crystalline silicon surfaces has been achieved by the application of very thin Ga{sub 2}O{sub 3} films prepared by atomic layer deposition using trimethylgallium (TMGa) and ozone (O{sub 3}) as the reactants. Surface recombination velocities as low as 6.1?cm/s have been recorded with films less than 4.5?nm thick. A range of deposition parameters has been explored, with growth rates of approximately 0.2?Å/cycle providing optimum passivation. The thermal activation energy for passivation of the Si-Ga{sub 2}O{sub 3} interface has been found to be approximately 0.5?eV. Depassivation of the interface was observed for prolonged annealing at increased temperatures. The activation energy for depassivation was measured to be 1.9?eV.

Allen, T. G., E-mail: thomas.allen@anu.edu.au; Cuevas, A. [Research School of Engineering, Australian National University, Canberra 0200 (Australia)

2014-07-21T23:59:59.000Z

327

Carbon nanotubes grown on bulk materials and methods for fabrication  

DOE Patents [OSTI]

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.

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

2011-11-08T23:59:59.000Z

328

Bulk Vitrification Castable Refractory Block Protection Study  

SciTech Connect (OSTI)

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.

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.

2005-05-01T23:59:59.000Z

329

Silicon bulk micromachined hybrid dimensional artifact.  

SciTech Connect (OSTI)

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.

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

2010-03-01T23:59:59.000Z

330

Running heading: Bulk density of a clayey subsoil Increase in the bulk density of a Grey Clay subsoil by  

E-Print Network [OSTI]

1 Running heading: Bulk density of a clayey subsoil Increase in the bulk density of a Grey Clay of the prisms were coated by material similar in composition to the topsoil and separated from as the profile dries over summer leading to widening of cracks between prismatic peds, (2) infilling of cracks

Boyer, Edmond

331

Reaction injection molding of silicon nitride ceramics having crystallized grain boundary phases  

SciTech Connect (OSTI)

A reaction injection molding process is described for preparing a sintered, silicon nitride-containing ceramic article comprising; (1) injecting into a heated mold a fluid, nondilatant mixture comprising (a) at least 40% by volume of a powder mixture of (i) from about 20 wt.% to about 98 wt.% silicon nitride, (ii) from about 0.5 wt.% to about 20 wt.% of a silicate glass-forming sintering aid, and (iii) from about 0.001 wt.% to about 80 wt.% of a high metal content transition metal silicide or a transition metal or metal compound that forms a high metal content silicide with silicon nitride under the conditions defined in steps (2) or (3), and (b) a curable silicon nitride precursor binder that is a liquid below its curing temperature, to cure the binder and produce a hardened molded article, (2) heating the hardened mol suitable atmosphere to a temperature sufficient to convert the cured binder to a silicon nitride-containing ceramic, and (3) sintering the article by (i) heating at a temperature of 1,300 to 1,800 C until a silicate glass forms, and (ii) further heating at a temperature of 1,300 to 1,800 C under a vacuum until oxygen is removed from the silicate glass and the glass crystallizes.

Lukacs, A. III; Matsumoto, R.L.K.

1993-08-31T23:59:59.000Z

332

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

DOE Patents [OSTI]

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.

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

1991-01-01T23:59:59.000Z

333

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

DOE Patents [OSTI]

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.

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

1991-09-10T23:59:59.000Z

334

Abstract--Titanium nitride (TiN) has been investigated as a material for MEMS hotplate heaters operating at high  

E-Print Network [OSTI]

TiN Bond pad TiN Figure 1. Schematic cross section of the hotplate. Titanium Nitride for MEMSAbstract--Titanium nitride (TiN) has been investigated as a material for MEMS hotplate heaters boundaries start to diffuse above one- third of the melting point. As a result, residual stresses relax [3

Technische Universiteit Delft

335

Radial elasticity of multi-walled boron nitride nanotubes  

SciTech Connect (OSTI)

We investigated the radial mechanical properties of multi-walled boron nitride nanotubes (MW-BNNTs) using atomic force microscopy. The employed MW-BNNTs were synthesized using pressurized vapor/condenser (PVC) methods and were dispersed in aqueous solution using ultrasonication methods with the aid of ionic surfactants. Our nanomechanical measurements reveal the elastic deformational behaviors of individual BNNTs with two to four tube walls in their transverse directions. Their effective radial elastic moduli were obtained through interpreting their measured radial deformation profiles using Hertzian contact mechanics models. Our results capture the dependences of the effective radial moduli of MW-BNNTs on both the tube outer diameter and the number of tube layers. The effective radial moduli of double-walled BNNTs are found to be several-fold higher than those of single-walled BNNTs within the same diameter range. Our work contributes directly to a complete understanding of the fundamental structural and mechanical properties of BNNTs and the pursuits of their novel structural and electronics applications.

Michael W. Smith, Cheol Park, Meng Zheng, Changhong Ke ,In-Tae Bae, Kevin Jordan

2012-02-01T23:59:59.000Z

336

Mechanical deformations of boron nitride nanotubes in crossed junctions  

SciTech Connect (OSTI)

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 2.21–4.67?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 4.2–7.6 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 0.18–0.29 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.

Zhao, Yadong; Chen, Xiaoming; Ke, Changhong, E-mail: cke@binghamton.edu [Department of Mechanical Engineering, State University of New York at Binghamton, Binghamton, New York 13902 (United States); Park, Cheol [NASA Langley Research Center, Hampton, Virginia 23681 (United States); Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia 22904 (United States); Fay, Catharine C. [NASA Langley Research Center, Hampton, Virginia 23681 (United States); Stupkiewicz, Stanislaw [Institute of Fundamental Technological Research, Warsaw (Poland)

2014-04-28T23:59:59.000Z

337

HIGH-EFFICIENCY NITRIDE-BASED SOLID-STATE LIGHTING  

SciTech Connect (OSTI)

In this semiannual report we summarize the progress obtained in the first six months with the support of DoE contract No.DE-FC26-01NT41203, entitled ''High-Efficiency Nitride-Based Solid-State Lighting''. The two teams, from the University of California at Santa Barbara (Principle Investigator: Dr. Shuji Nakamura) and Rensselaer Polytechnic Institute (led by Dr. N. Narendran), are pursuing the goals of this contract from thin film growth, characterization, and packaging standpoints. The UCSB team has made significant progress in the development of GaN vertical cavity surface-emitting lasers (VCSELs) as well as light-emitting diodes (LEDs) with AlGaN active regions emitting in the ultraviolet (UV). The Rensselaer team has developed target specifications for some of the key parameters for the proposed solid-state lighting system, including a luminous flux requirement matrix for various lighting applications, optimal spectral power distributions, and the performance characteristics of currently available commercial LEDs for eventual comparisons to the devices developed in the scope of this project.

Dr. Paul T. Fini; Prof. Shuji Nakamura

2002-04-30T23:59:59.000Z

338

HIGH-EFFICIENCY NITRIDE-BASED SOLID-STATE LIGHTING  

SciTech Connect (OSTI)

In this annual report we summarize the progress obtained in the first year with the support of DoE contract No.DE-FC26-01NT41203, entitled ''High-Efficiency Nitride-Based Solid-State Lighting''. The two teams, from the University of California at Santa Barbara (Principle Investigator: Dr. Shuji Nakamura) and Rensselaer Polytechnic Institute (led by Dr. N. Narendran), are pursuing the goals of this contract from thin film growth, characterization, and packaging standpoints. The UCSB team has made significant progress in the development of GaN vertical cavity surface-emitting lasers (VCSELs) as well as light-emitting diodes (LEDs) with AlGaN active regions emitting in the ultraviolet (UV). The Rensselaer team has developed target specifications for some of the key parameters for the proposed solid-state lighting system, including a luminous flux requirement matrix for various lighting applications, optimal spectral power distributions, and the performance characteristics of currently available commercial LEDs for eventual comparisons to the devices developed in the scope of this project.

Dr. Paul T. Fini; Prof. Shuji Nakamura

2002-09-01T23:59:59.000Z

339

SUMMARY ON TITANIUM NITRIDE COATING OF SNS RING VACUUM CHAMBERS.  

SciTech Connect (OSTI)

The inner surfaces of the 248 m Spallation Neutron Source (SNS) accumulator ring vacuum chambers are coated with {approx}100nm of titanium nitride (TiN) to reduce the secondary electron yield (SEY) of the chamber walls. There are approximately 135 chambers and kicker modules, some up to 5m in length and 36cm in diameter, coated with TiN. The coating is deposited by means of reactive DC magnetron sputtering -using a - cylindrical cathode with internal permanent magnets. This cathode configuration generates a deposition-rate sufficient to meet the required production schedule and produces stoichiometric films with good adhesion, low SEY and acceptable outgassing. Moreover, the cathode magnet configuration allows for simple changes in length and has been adapted to coat the wide variety of chambers and components contained within the arcs, injection, extraction, collimation and RF straight sections. Chamber types and quantities as well as the cathode configurations are presented herein. The unique coating requirements of the injection kicker ceramic chambers and the extraction kicker ferrite surface will be emphasized. A brief summary of the salient coating properties is given including the interdependence of SEY as a function of surface roughness and its effect on outgassing.

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

2005-05-16T23:59:59.000Z

340

Neutrino mass, bulk majoron and neutrinoless double beta decay  

E-Print Network [OSTI]

A new economical model for neutrino masses is proposed in the context of brane bulk scenarios for particle physics, where global B-L symmetry of the standard model is broken spontaneously by a gauge singlet Higgs field in the bulk. This leads to a bulk majoron whose KK excitations may make it visible if neutrinoless double beta decay if the string scale is close to a TeV. It also leads to neutron-anti-neutron oscillation process with transition times which can be in the range accessible to proposed experiments.

R. N. Mohapatra; A. Perez-Lorenzana; C. A. de S. Pires

2000-08-15T23:59:59.000Z

Note: This page contains sample records for the topic "bulk gallium nitride" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Brane-Bulk energy exchange and agegraphic dark energy  

E-Print Network [OSTI]

We consider the agegraphic models of dark energy in a braneworld scenario with brane-bulk energy exchange. We assume that the adiabatic equation for the dark matter is satisfied while it is violated for the agegraphic dark energy due to the energy exchange between the brane and the bulk. Our study shows that with the brane-bulk interaction, the equation of state parameter of agegraphic dark energy on the brane, $w_D$, can have a transition from normal state where $w_D >-1 $ to the phantom regime where $w_D energy always satisfies $w^{\\mathrm{eff}}_D\\geq-1$.

Ahmad Sheykhi

2010-02-06T23:59:59.000Z

342

Shear strain mediated magneto-electric effects in composites of piezoelectric lanthanum gallium silicate or tantalate and ferromagnetic alloys  

SciTech Connect (OSTI)

Shear strain mediated magneto-electric (ME) coupling is studied in composites of piezoelectric Y-cut lanthanum gallium silicate (LGS) or tantalate (LGT) and ferromagnetic Fe-Co-V alloys. It is shown that extensional strain does not result in ME effects in these layered composites. Under shear strain generated by an ac and dc bias magnetic fields along the length and width of the sample, respectively, strong ME coupling is measured at low-frequencies and at mechanical resonance. A model is discussed for the ME effects. These composites of Y-cut piezoelectrics and ferromagnetic alloys are of importance for shear strain based magnetic field sensors.

Sreenivasulu, G.; Piskulich, E.; Srinivasan, G., E-mail: srinivas@oakland.edu [Physics Department, Oakland University, Rochester, Michigan 48409 (United States); Qu, P.; Qu, Hongwei [Electrical and Computer Engineering, Oakland University, Rochester, Michigan 48309 (United States); Petrov, V. M. [Institute of Electronic Information Systems, Novgorod State University, Veliky Novgorod (Russian Federation); Fetisov, Y. K. [Moscow State Technical University of Radio Engineering, Electronics and Automation, Moscow 19454 (Russian Federation); Nosov, A. P. [Institute of Metal Physics, Ural Division of Russian Academy of Sciences, 18 S. Kovalevskaya St, Ekaterinburg 620990 (Russian Federation)

2014-07-21T23:59:59.000Z

343

The internal-nitriding behavior of Co-Fe-Al alloys  

SciTech Connect (OSTI)

Co-10Fe, Co-20Fe, and Co-40Fe alloys containing 3 at.% Al were internally nitrided in NH{sub 3}/H{sub 2} mixtures over the range 700--1000 C. The kinetics of thickening of the internal-reaction zone followed the parabolic rate law, suggesting that solid-state diffusion was rate controlling. Nitrogen permeabilities were obtained for each alloy. AlN was the only nitride to form for all materials and at all temperatures. At high temperature, the nitride precipitates formed hexagonal plates near the surface, the precipitates becoming more blocky near the reaction front. Precipitate size increased with increasing depth in the alloy and increasing temperature, because of competition between nucleation and growth processes. Increasing iron content increased the reaction kinetics due to increased nitrogen solubility with increasing iron content.

Chen, I.C. [Raytheon Systems Co., El Segundo, CA (United States). Sensors and Electronics Systems] [Raytheon Systems Co., El Segundo, CA (United States). Sensors and Electronics Systems; Douglass, D.L. [Univ. of Arizona, Tucson, AZ (United States). Arizona Materials Labs.] [Univ. of Arizona, Tucson, AZ (United States). Arizona Materials Labs.

1999-10-01T23:59:59.000Z

344

Formation of Protective Nitride Surfaces for PEM Fuel Cell Metallic Bipolar Plates  

SciTech Connect (OSTI)

Selective gas nitridation of model Ni-base alloys was used to form dense, electrically-conductive and corrosion-resistant nitride surface layers, including TiN, VN, CrN, Cr2N, as well as a complex NiNbVN phase. Evaluation for use as a protective surface for metallic bipolar plates in proton exchange membrane fuel cells (PEMFC) indicated that CrN/Cr2N base surfaces hold promise to meet Department of Energy (DOE) performance goals for automotive applications. The thermally grown CrN/Cr2N surface formed on model Ni-Cr base alloys exhibited good stability and low electrical resistance in single-cell fuel cell testing under simulated drive-cycle conditions. Recent results indicate that similar protective Cr-nitride surfaces can be formed on less expensive Fe-Cr base alloys potentially capable of meeting DOE cost goals.

Brady, Michael P [ORNL; Yang, Bing [ORNL; Wang, Heli [National Renewable Energy Laboratory (NREL); Turner, John [National Renewable Energy Laboratory (NREL); More, Karren Leslie [ORNL; Wilson, Mahlon [Los Alamos National Laboratory (LANL); Garzon, Fernando [Los Alamos National Laboratory (LANL)

2006-01-01T23:59:59.000Z

345

Thermodynamic stability and unusual strength of ultra-incompressible rhenium nitrides  

SciTech Connect (OSTI)

We report on a comprehensive study of thermodynamic and mechanical properties as well as a bond-deformation mechanism on ultra-incompressible Re{sub 2} N and Re{sub 3} N. The introduction of nitrogen into the rhenium lattice leads to thermodynamic instability in Re{sub 2} N at ambient conditions and enhanced incompressibility and strength for both rhenium nitrides. Rhenium nitrides, however, show substantially lower ideal shear strength than hard ReB{sub 2} and superhard c -BN, suggesting that they cannot be intrinsically superhard. An intriguing soft “ionic bond mediated plastic deformation” mechanism is revealed to underline the physical origin of their unusual mechanical strength. These results suggest a need to reformulate the design concept of intrinsically superhard transition-metal nitrides, borides, and carbides.

Zhang, R. F.; Lin, Zhijun; Mao, Ho-kwang; Zhao, Yusheng

2011-01-01T23:59:59.000Z

346

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

SciTech Connect (OSTI)

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.

Seyed-Talebi, Seyedeh Mozhgan [Shahid Chamran University, Golestan boulevard, Ahvaz, Khouzestan (Iran, Islamic Republic of); Neek-Amal, M., E-mail: neekamal@srttu.edu [Shahid Rajaee Teacher Training University, Lavizan, Tehran (Iran, Islamic Republic of)

2014-10-21T23:59:59.000Z

347

Electron/phonon coupling in group-IV transition-metal and rare-earth nitrides  

SciTech Connect (OSTI)

Transport electron/phonon coupling parameters and Eliashberg spectral functions ?{sub tr}{sup 2}F(??) are determined for group-IV transition-metal (TM) nitrides TiN, ZrN, and HfN, and the rare-earth (RE) nitride CeN using an inversion procedure based upon temperature-dependent (4 < T < 300 K) resistivity measurements of high-crystalline-quality stoichiometric epitaxial films grown on MgO(001) by magnetically-unbalanced reactive magnetron sputtering. Transport electron/phonon coupling parameters ?{sub tr} vary from 1.11 for ZrN to 0.82 for HfN, 0.73 for TiN, and 0.44 for CeN. The small variation in ?{sub tr} among the TM nitrides and the weak coupling in CeN are consistent with measured superconducting transition temperatures 10.4 (ZrN), 9.18 (HfN), 5.35 (TiN), and <4 K for CeN. The Eliashberg spectral function describes the strength and energy spectrum of electron/phonon coupling in conventional superconductors. Spectral peaks in ?{sup 2}F(??), corresponding to regions in energy-space for which electrons couple to acoustic ??{sub ac} and optical ??{sub op} phonon modes, are centered at ??{sub ac} = 33 and ??{sub op} = 57 meV for TiN, 25 and 60 meV for ZrN, 18 and 64 meV for HfN, and 21 and 39 meV for CeN. The acoustic modes soften with increasing cation mass; optical mode energies remain approximately constant for the TM nitrides, but are significantly lower for the RE nitride due to a lower interatomic force constant. Optical/acoustic peak-intensity ratios are 1.15 ± 0.1 for all four nitrides, indicating similar electron/phonon coupling strengths ?{sub tr}(??) for both modes.

Mei, A. B.; Rockett, A. [Departments of Materials Science, Physics, and the Materials Research Laboratory, University of Illinois, 104 South Goodwin, Urbana, Illinois 61801 (United States)] [Departments of Materials Science, Physics, and the Materials Research Laboratory, University of Illinois, 104 South Goodwin, Urbana, Illinois 61801 (United States); Hultman, L. [Thin Film Physics Division, Department of Physics (IFM), Linköping University, SE-58183 Linköping (Sweden)] [Thin Film Physics Division, Department of Physics (IFM), Linköping University, SE-58183 Linköping (Sweden); Petrov, I.; Greene, J. E. [Departments of Materials Science, Physics, and the Materials Research Laboratory, University of Illinois, 104 South Goodwin, Urbana, Illinois 61801 (United States) [Departments of Materials Science, Physics, and the Materials Research Laboratory, University of Illinois, 104 South Goodwin, Urbana, Illinois 61801 (United States); Thin Film Physics Division, Department of Physics (IFM), Linköping University, SE-58183 Linköping (Sweden)

2013-11-21T23:59:59.000Z

348

Effects of surface grinding conditions on the reciprocating friction and wear behavior of silicon nitride  

SciTech Connect (OSTI)

The relationship between two significantly different surface grinding conditions and the reciprocating ball-on-flat friction and wear behavior of a high-quality, structural silicon nitride material (GS-44) was investigated. The slider materials were silicon nitride NBD 200 and 440C stainless steel. Two machining conditions were selected based on extensive machining and flexural strength test data obtained under the auspices of an international, interlaboratory grinding study. The condition categorized as {open_quotes}low strength{close_quote} grinding used a coarse 80 grit wheel and produced low flexure strength due to machining-induced flaws in the surface. The other condition, regarded as {open_quotes}high strength grinding,{close_quotes} utilized a 320 grit wheel and produced a flexural strength nearly 70% greater. Grinding wheel surface speeds were 35 and 47 m/s. Reciprocating sliding tests were conducted following the procedure described in a newly-published ASTM standard (G- 133) for linearly-reciprocating wear. Tests were performed in directions both parallel and perpendicular to the grinding marks (lay) using a 25 N load, 5 Hz reciprocating frequency, 10 mm stroke length, and 100 m of sliding at room temperature. The effects of sliding direction relative to the lay were more pronounced for stainless steel than for silicon nitride sliders. The wear of stainless steel was less than the wear of the silicon nitride slider materials because of the formation of transfer particles which covered the sharp edges of the silicon nitride grinding grooves and reduced abrasive contact. The wear of the GS-44 material was much greater for the silicon nitride sliders than for the stainless steel sliders. The causes for the effects of surface-grinding severity and sliding direction on friction and wear of GS-44 and its counterface materials are explained.

Blau, P.J.; Martin, R.L.; Zanoria, E.S.

1997-12-31T23:59:59.000Z

349

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

SciTech Connect (OSTI)

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.

Deng, C.Z.; Pynenburg, R.A.J.; Tsai, K.C. [Pinnacle Research Inst., Inc., Los Gatos, CA (United States)

1998-04-01T23:59:59.000Z

350

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

DOE Patents [OSTI]

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.

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

2014-03-18T23:59:59.000Z

351

Microstructural characterization of silicon nitride ceramics processed by pressureless sintering, overpressure sintering, and sinter/HIP  

SciTech Connect (OSTI)

Silicon nitride ceramics of the same nominal sialon composition have been sintered under different conditions including atmospheric sintering, overpressure sintering, reaction bonded (nitrided pressureless sinter) and sinter/HIP cycles. The sintered ceramics, which exhibited dramatic differences in fracture toughness, have been characterized by x-ray diffraction, scanning electron microscopy, analytical transmission electron microscopy, and image analysis techniques. Fracture toughness data have been correlated to the microstructural and chemical analysis of the grain boundary phases. The microstructure was the strongest influencing factor on the observed fracture toughness difference. 5 refs., 5 tabs.

Selkregg, K.R. (Oak Ridge National Lab., TN (USA)); More, K.L.; Seshadri, S.G.; McMurtry, C.H. (Carborundum Co., Niagara Falls, NY (USA))

1990-01-01T23:59:59.000Z

352

Structural and economic analysis of capesize bulk carriers  

E-Print Network [OSTI]

Structural failures of bulk carriers continue to account for the loss of many lives every year. Capes are particularly vulnerable to cracking because of their large length, their trade in high density cargos, and the high ...

Hadjiyiannis, Nicholas

2010-01-01T23:59:59.000Z

353

Stresses resulting from compression of bulk cotton lint fibers  

E-Print Network [OSTI]

The modulus of elasticity, Poisson's ratio and shear modulus of bulk cotton lint fibers were determined. The cotton lint was compressed in an MTS machine to a predetermined density, and the resilient forces induced by the cotton lint after being...

Chimbombi, Ezekiel Maswe

1998-01-01T23:59:59.000Z

354

A bulk-flow model of angled injection Lomakin bearings  

E-Print Network [OSTI]

A bulk-flow model for determination of the leakage and dynamic force characteristics of angled injection Lomakin bearings is presented. Zeroth- and first-order equations describe the equilibrium flow for a centered bearing and the perturbed flow...

Soulas, Thomas Antoine Theo

2001-01-01T23:59:59.000Z

355

Incomplete Exciton Harvesting from Fullerenes in Bulk Heterojunction Solar  

E-Print Network [OSTI]

Incomplete Exciton Harvesting from Fullerenes in Bulk Heterojunction Solar Cells George F. Burkhard generation (absorp- tion), exciton harvesting (the process of excitons migrating to the donor materials decay radiatively, so exciton harvesting is usually evaluated by observing photolumines- cence

McGehee, Michael

356

Mechanical Properties of Bulk Metallic Glasses and Composites  

E-Print Network [OSTI]

We have studied the mechanical properties of monolithic bulk metallic glasses and composite in the La based alloys. La???yAl??(Cu, Ni)y (y=24 to 32) alloy systems was used to cast the ...

Lee, M.L.

357

Compositional ordering and stability in nanostructured, bulk thermoelectric alloys.  

SciTech Connect (OSTI)

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.

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

2009-09-01T23:59:59.000Z

358

Costs, Savings and Financing Bulk Tanks on Texas Dairy Farms.  

E-Print Network [OSTI]

\\ BULLETIN 904 MAY 1958 .t(. :a ,s - / cwdh\\@ Costs, Savi~gs;.itd Financing Bulk Tanks on Texas Dairy Farms . ?. I I 1 i I I ! ,:ravings in hauling - 10 cents I \\ \\ 1 \\ savings in hauling - 15 cents -----------____--- 'savings... in hauling - 20 cents Annual production, 1,000 pounds Estimated number of years required for savings from a bulk tank to equal additional costs at different levels of production and savings in hauling costs. TEXAS AGRICULTURAL EXPERIMEN'T STATION R. D...

Moore, Donald S.; Stelly, Randall; Parker, Cecil A.

1958-01-01T23:59:59.000Z

359

RAPID/BulkTransmission/Texas | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia: EnergyPotentialUrbanUtilityScalePVCapacityPulaskiRAPID/BulkTransmission/Texas < RAPID‎ | BulkTransmission

360

RAPID/BulkTransmission/Water Quality | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia: EnergyPotentialUrbanUtilityScalePVCapacityPulaskiRAPID/BulkTransmission/Texas <RAPID/BulkTransmission/Water

Note: This page contains sample records for the topic "bulk gallium nitride" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

RAPID/BulkTransmission/Wyoming | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia: EnergyPotentialUrbanUtilityScalePVCapacityPulaskiRAPID/BulkTransmission/TexasRAPID/BulkTransmission/Wyoming <

362

Finsler geometric perspective on the bulk flow in the universe  

E-Print Network [OSTI]

Astronomical observations showed that there may exist a bulk flow with peculiar velocities in the universe, which contradicts with the (\\Lambda)CDM model. The bulk flow reveals that the observational universe is anisotropic at large scales. In fact, a more reliable observation on the anisotropy of spacetime comes from the CMB power spectra. The WMAP and Planck satellites both show that there is a hemispherical power asymmetry at large-angular scales. In this paper, we propose a "wind" scenario to the bulk flow (or the anisotropy of spacetime). Under the influence of the "wind", the spacetime metric could become a Finsler structure. By resolving the null geodesic equation, we obtain the modified luminosity distance, which has a dipolar form at the leading order. Thus, the "wind" describes well the bulk flow. In addition, we perform a least-(\\chi^2) fit to the data of type Ia supernovae (SNe Ia) in the Union2.1 compilation. The peculiar velocity of the bulk flow has an upper limit (v_{bulk}\\lesssim 4000 \\rm{km/s}), which is compatible with all the existing observational values.

Zhe Chang; Ming-Hua Li; Sai Wang

2013-03-07T23:59:59.000Z

363

Cosmic No Hair for Braneworlds with a Bulk Dilaton Field  

E-Print Network [OSTI]

Braneworld cosmology supported by a bulk scalar field with an exponential potential is developed. A general class of separable backgrounds for both single and two-brane systems is derived, where the bulk metric components are given by products of world-volume and bulk coordinates and the world-volumes represent any anisotropic and inhomogeneous solution to an effective four-dimensional Brans-Dicke theory of gravity. We deduce a cosmic no hair theorem for all ever expanding, spatially homogeneous Bianchi world-volumes and find that the spatially flat and isotropic inflationary scaling solution represents a late-time attractor when the bulk potential is sufficiently flat. The dependence of this result on the separable nature of the bulk metric is investigated by applying the techniques of Hamilton-Jacobi theory to five-dimensional Einstein gravity. We employ the spatial gradient expansion method to determine the asymptotic form of the bulk metric up to third-order in spatial gradients. It is found that the condition for the separable form of the metric to represent the attractor of the system is precisely the same as that for the four-dimensional world-volume to isotropize. We also derive the fourth-order contribution to the Hamilton-Jacobi generating functional. Finally, we conclude by placing our results within the context of the holographic approach to braneworld cosmology.

James E. Lidsey; David Seery

2005-09-22T23:59:59.000Z

364

Desorption and sublimation kinetics for fluorinated aluminum nitride surfaces  

SciTech Connect (OSTI)

The adsorption and desorption of halogen and other gaseous species from surfaces is a key fundamental process for both wet chemical and dry plasma etch and clean processes utilized in nanoelectronic fabrication processes. Therefore, to increase the fundamental understanding of these processes with regard to aluminum nitride (AlN) surfaces, temperature programmed desorption (TPD) and x-ray photoelectron spectroscopy (XPS) have been utilized to investigate the desorption kinetics of water (H{sub 2}O), fluorine (F{sub 2}), hydrogen (H{sub 2}), hydrogen fluoride (HF), and other related species from aluminum nitride thin film surfaces treated with an aqueous solution of buffered hydrogen fluoride (BHF) diluted in methanol (CH{sub 3}OH). Pre-TPD XPS measurements of the CH{sub 3}OH:BHF treated AlN surfaces showed the presence of a variety of Al-F, N-F, Al-O, Al-OH, C-H, and C-O surfaces species in addition to Al-N bonding from the AlN thin film. The primary species observed desorbing from these same surfaces during TPD measurements included H{sub 2}, H{sub 2}O, HF, F{sub 2}, and CH{sub 3}OH with some evidence for nitrogen (N{sub 2}) and ammonia (NH{sub 3}) desorption as well. For H{sub 2}O, two desorption peaks with second order kinetics were observed at 195 and 460?°C with activation energies (E{sub d}) of 51?±?3 and 87?±?5?kJ/mol, respectively. Desorption of HF similarly exhibited second order kinetics with a peak temperature of 475?°C and E{sub d} of 110?±?5?kJ/mol. The TPD spectra for F{sub 2} exhibited two peaks at 485 and 585?°C with second order kinetics and E{sub d} of 62?±?3 and 270?±?10?kJ/mol, respectively. These values are in excellent agreement with previous E{sub d} measurements for desorption of H{sub 2}O from SiO{sub 2} and AlF{sub x} from AlN surfaces, respectively. The F{sub 2} desorption is therefore attributed to fragmentation of AlF{sub x} species in the mass spectrometer ionizer. H{sub 2} desorption exhibited an additional high temperature peak at 910?°C with E{sub d}?=?370?±?10?kJ/mol that is consistent with both the dehydrogenation of surface AlOH species and H{sub 2} assisted sublimation of AlN. Similarly, N{sub 2} exhibited a similar higher temperature desorption peak with E{sub d}?=?535?±?40?kJ/mol that is consistent with the activation energy for direct sublimation of AlN.

King, Sean W., E-mail: sean.king@intel.com; Davis, Robert F. [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Nemanich, Robert J. [Department of Physics, North Carolina State University, Raleigh, North Carolina 27695 (United States)

2014-09-01T23:59:59.000Z

365

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

DOE Patents [OSTI]

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).

Curtis, Calvin J. (Lakewood, CO); Miedaner, Alexander (Boulder, CO); Van Hest, Maikel (Lakewood, CO); Ginley, David S. (Evergreen, CO); Nekuda, Jennifer A. (Lakewood, CO)

2011-11-15T23:59:59.000Z

366

The reaction of carbon tetrachloride with gallium arsenide ,,001... L. Li., S, Gan, B.-K. Han, H. Qi, and R. F. Hicksa)  

E-Print Network [OSTI]

The reaction of carbon tetrachloride with gallium arsenide ,,001... L. Li., S, Gan, B.-K. Han, H, California 90095 Received 26 June 1997; accepted for publication 30 December 1997 Carbon tetrachloride of steps during the vapor-phase epitaxial growth of III­V compound semiconductors.3,4 Carbon tetrachloride

Li, Lian

367

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,...

368

The Role of Surface Chemistry and Bulk Properties on the Cycling...  

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

The Role of Surface Chemistry and Bulk Properties on the Cycling and Rate Capability of Lithium Positive Electrode Materials The Role of Surface Chemistry and Bulk Properties on...

369

Formation of BN and AlBN during nitridation of sapphire using RF plasma sources[Radiofrequency  

SciTech Connect (OSTI)

Evidence is presented that nitrogen plasma sources utilizing a pyrolytic boron nitride liner may be a significant source of B contamination during growth and processing. Auger electron spectroscopy analysis performed during nitridation of sapphire indicate the resulting layers contain a significant amount of BN. The formation of Al{sub 1{minus}x}B{sub x}N would explain the observation of a lattice constant several percent smaller than AlN as measured by reflection high-energy electron diffraction. The presence of cubic inclusions in layers grown on such a surface may be related to the segregation of BN during the nitridation into its cubic phase.

Ptak, A.J.; Ziemer, K.S.; Holbert, L.J.; Stinespring, C.D.; Myers, T.H.

2000-07-01T23:59:59.000Z

370

Method for Improving Mg Doping During Group-III Nitride MOCVD  

DOE Patents [OSTI]

A method for improving Mg doping of Group III-N materials grown by MOCVD preventing condensation in the gas phase or on reactor surfaces of adducts of magnesocene and ammonia by suitably heating reactor surfaces between the location of mixing of the magnesocene and ammonia reactants and the Group III-nitride surface whereon growth is to occur.

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

2008-11-11T23:59:59.000Z

371

Formation of Nickel Silicide from Direct-Liquid-Injection Chemical-Vapor-Deposited Nickel Nitride Films  

E-Print Network [OSTI]

. Published April 28, 2010. Metal silicides such as TiSi2 and CoSi2 have been commonly used as the contactsFormation of Nickel Silicide from Direct-Liquid-Injection Chemical-Vapor-Deposited Nickel Nitride as the intermediate for subsequent conversion into nickel silicide NiSi , which is a key material for source, drain

372

Characterization of multilayer nitride coatings by electron microscopy and modulus mapping  

SciTech Connect (OSTI)

This paper discusses multi-scale characterization of physical vapour deposited multilayer nitride coatings using a combination of electron microscopy and modulus mapping. Multilayer coatings with a triple layer structure based on TiAlN and nanocomposite nitrides with a nano-multilayered architecture were deposited by Cathodic arc deposition and detailed microstructural studies were carried out employing Energy Dispersive Spectroscopy, Electron Backscattered Diffraction, Focused Ion Beam and Cross sectional Transmission Electron Microscopy in order to identify the different phases and to study microstructural features of the various layers formed as a result of the deposition process. Modulus mapping was also performed to study the effect of varying composition on the moduli of the nano-multilayers within the triple layer coating by using a Scanning Probe Microscopy based technique. To the best of our knowledge, this is the first attempt on modulus mapping of cathodic arc deposited nitride multilayer coatings. This work demonstrates the application of Scanning Probe Microscopy based modulus mapping and electron microscopy for the study of coating properties and their relation to composition and microstructure. - Highlights: • Microstructure of a triple layer nitride coating studied at multiple length scales. • Phases identified by EDS, EBSD and SAED (TEM). • Nanolayered, nanocomposite structure of the coating studied using FIB and TEM. • Modulus mapping identified moduli variation even in a nani-multilayer architecture.

Pemmasani, Sai Pramod [International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Balapur P.O., Hyderabad — 500005 India (India); School of Engineering Sciences and Technology, University of Hyderabad, Gachibowli, Hyderabad — 500046 India (India); Rajulapati, Koteswararao V. [School of Engineering Sciences and Technology, University of Hyderabad, Gachibowli, Hyderabad — 500046 India (India); Ramakrishna, M.; Valleti, Krishna [International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Balapur P.O., Hyderabad — 500005 India (India); Gundakaram, Ravi C., E-mail: ravi.gundakaram@arci.res.in [International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Balapur P.O., Hyderabad — 500005 India (India); Joshi, Shrikant V. [International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Balapur P.O., Hyderabad — 500005 India (India)

2013-07-15T23:59:59.000Z

373

Numerical simulation of the heat transfer in amorphous silicon nitride membrane-based microcalorimeters  

E-Print Network [OSTI]

Numerical simulation of the heat transfer in amorphous silicon nitride membrane July 2003 Numerical simulations of the two-dimensional 2D heat flow in a membrane-based microcalorimeter have been performed. The steady-state isotherms and time-dependent heat flow have been calculated

Hellman, Frances

374

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

DOE Patents [OSTI]

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.

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

1999-01-01T23:59:59.000Z

375

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

DOE Patents [OSTI]

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.

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

2002-01-01T23:59:59.000Z

376

Line-source E beam crystallization of Si on silicon nitride layers  

SciTech Connect (OSTI)

The use of a swept line-source electron beam is reported for liquid phase recrystallization of Si films on Si/sub 3/N/sub 4/ layers over Si substrates. For the case of 5000A of Si on 1000A of Si/sub 3/N/sub 4/ layers over Si the growth of Si crystalline regions as large as 0.5 x 5 mm of predominately (100) orientation normal to the film and (010) in the sweep direction has been demonstrated. The nucleation of grain growth for this case occurred at small defects in the nitride layer at the edge of the treated area, growing out as far as 500 ..mu..m over intact nitride. Thicker nitrides (2500A) remained intact at power densities useful for treating the Si film. For this thicker nitride non-seeded growth is demonstrated for single and repetitively melted Si. In all cases the surface morphology of the regrown regions is suggestive of rapid growth along <100> directions.

Knapp, J.A.; Picraux, S.T.; Lee, K.; Gibbons, J.F.; Sedgwick, T.O.; Depp, S.W.

1981-01-01T23:59:59.000Z

377

CHARGE STABILITY IN LPCVD SILICON NITRIDE FOR SURFACE PASSIVATION OF SILICON SOLAR CELLS  

E-Print Network [OSTI]

CHARGE STABILITY IN LPCVD SILICON NITRIDE FOR SURFACE PASSIVATION OF SILICON SOLAR CELLS Yongling Ren, Natalita M Nursam, Da Wang and Klaus J Weber Centre for Sustainable Energy Systems, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 0200, Australia ABSTRACT

378

Disordered graphene and boron nitride in a microwave tight-binding analogue S. Barkhofen,1  

E-Print Network [OSTI]

Disordered graphene and boron nitride in a microwave tight-binding analogue S. Barkhofen,1 M Sophia-Antipolis, 06108 Nice, France (Dated: December 20, 2012) Experiments on hexagonal graphene of the high flexibility of the discs positions, consequences of the disorder introduced in the graphene

Paris-Sud XI, Université de

379

Reversible Intercalation of Hexagonal Boron Nitride with Brnsted Nina I. Kovtyukhova,*,  

E-Print Network [OSTI]

materials.1-3 Intercalation reactions are often used as the first step in exfoliation of lamellar crystals dichalogenides,10,12 and hexagonal boron nitride (h-BN)13-15 can be mechanically exfoliated to form crystalline, several solution-based chem- ical approaches have been studied.10,16-22 Among these, only exfoliation

380

Effect of contact metals on the piezoelectric properties of aluminum nitride thin films  

SciTech Connect (OSTI)

The converse piezoelectric response of aluminum nitride evaluated using standard metal insulator semiconductor structures has been found to exhibit a linear dependence on the work function of the metal used as the top electrode. The apparent d33 of the 150–1100 nm films also depends on the dc bias applied to the samples.

Harman, J.P.; Kabulski, A. (West Virginia U., Morgantown, WV); Pagan, V.R. (West Virginia U., Morgantown, WV); Famouri, K. (West Virginia U., Morgantown, WV); Kasarla, K.R.; Rodak, L.E. (West Virginia U., Morgantown, WV); Hensel, J.P.; Korakakis, D.

2008-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "bulk gallium nitride" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Tuning the optical properties of dilute nitride site controlled quantum dots  

SciTech Connect (OSTI)

We show that deterministic control of the properties of pyramidal site-controlled quantum dots (QD) could be achieved by exposing the QD layer to nitrogen precursor unsymmetrical dimethylhydrazine (UDMHy). The properties that could be tuned include an expected emission reduction in dilute nitride materials, excitonic pattern (biexciton binding energy) and improved carrier confinement potential symmetry (reduced fine-structure splitting)

Juska, G.; Dimastrodonato, V.; Mereni, L. O.; Gocalinska, A.; Pelucchi, E. [Tyndall National Institute, University College Cork, Lee Maltings, Cork (Ireland)

2013-12-04T23:59:59.000Z

382

Characterization of the nitrogen split interstitial defect in wurtzite aluminum nitride using density functional theory  

SciTech Connect (OSTI)

We carried out Heyd-Scuseria-Ernzerhof hybrid density functional theory plane wave supercell calculations in wurtzite aluminum nitride in order to characterize the geometry, formation energies, transition levels, and hyperfine tensors of the nitrogen split interstitial defect. The calculated hyperfine tensors may provide useful fingerprint of this defect for electron paramagnetic resonance measurement.

Szállás, A., E-mail: szallas.attila@wigner.mta.hu [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Szász, K. [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Institute of Physics, Eötvös University, Pázmány Péter sétány 1/A, H-1117 Budapest (Hungary); Trinh, X. T.; Son, N. T.; Janzén, E. [Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping (Sweden); Gali, A., E-mail: gali.adam@wigner.mta.hu [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Department of Atomic Physics, Budapest University of Technology and Economics, Budafoki út 8, H-1111 Budapest (Hungary)

2014-09-21T23:59:59.000Z

383

Evaluation and silicon nitride internal combustion engine components. Final report, Phase I  

SciTech Connect (OSTI)

The feasibility of silicon nitride (Si{sub 3}N{sub 4}) use in internal combustion engines was studied by testing three different components for wear resistance and lower reciprocating mass. The information obtained from these preliminary spin rig and engine tests indicates several design changes are necessary to survive high-stress engine applications. The three silicon nitride components tested were valve spring retainers, tappet rollers, and fuel pump push rod ends. Garrett Ceramic Components` gas-pressure sinterable Si{sub 3}N{sub 4} (GS-44) was used to fabricate the above components. Components were final machined from densified blanks that had been green formed by isostatic pressing of GS-44 granules. Spin rig testing of the valve spring retainers indicated that these Si{sub 3}N{sub 4} components could survive at high RPM levels (9,500) when teamed with silicon nitride valves and lower spring tension than standard titanium components. Silicon nitride tappet rollers showed no wear on roller O.D. or I.D. surfaces, steel axles and lifters; however, due to the uncrowned design of these particular rollers the cam lobes indicated wear after spin rig testing. Fuel pump push rod ends were successful at reducing wear on the cam lobe and rod end when tested on spin rigs and in real-world race applications.

Voldrich, W. [Allied-Signal Aerospace Co., Torrance, CA (United States). Garrett Ceramic Components Div.

1992-04-01T23:59:59.000Z

384

LPCVD SILICON NITRIDE-ON-SILICON SPACER TECHNOLOGY H. W. van Zeijl, L.K. Nanver  

E-Print Network [OSTI]

of obtaining self-aligned sub- lithographic dimensions. In many processes were spacers are applied to separate-etching affects the dimensions of the spacer which could lead to a lack of control over the spacer-related deviceLPCVD SILICON NITRIDE-ON-SILICON SPACER TECHNOLOGY H. W. van Zeijl, L.K. Nanver DIMES Delft

Technische Universiteit Delft

385

Base-contact proximity effects in bipolar transistors with nitride-spacer technology  

E-Print Network [OSTI]

-lithographic dimensions. For example, in the double polysilicon bipolar transistor, spacers are used to separate the baseBase-contact proximity effects in bipolar transistors with nitride-spacer technology Henk van Zeijl-BJT's with spacer separated Al/Si emitter and base contacts are fabricated and characterized. Due to the proximity

Technische Universiteit Delft

386

Electronic structure and pairwise interactions in substoichiometric transition metal carbides and nitrides  

E-Print Network [OSTI]

1001 Electronic structure and pairwise interactions in substoichiometric transition metal carbides observations expéri- mentales. Abstract 2014 In substoichiometric transition metal carbides and nitrides This paper is devoted to the study of the ordering processes in substoichiometric transition metal carbi- des

Paris-Sud XI, Université de

387

ORDER AND DISORDER IN CARBIDES AND NITRIDES Ch. H. DE NOVION and V. MAURICE  

E-Print Network [OSTI]

transition metals, rare earths and actinides react with carbon and nitrogen to form metallic carbides experimental evidence for short and long-range ordering of point defects in metallic transition metal, rareCOMPOUNDS. ORDER AND DISORDER IN CARBIDES AND NITRIDES Ch. H. DE NOVION and V. MAURICE SESI, C

Paris-Sud XI, Université de

388

Effect of swift heavy ion irradiations in polycrystalline aluminum nitride J.C. Nappa,*  

E-Print Network [OSTI]

conductivity, aluminum nitride may be a serious candidate as fuel coating for the Gas Fast Reactor. However.41.Bm, 78.60.Kn, 78.20.Ci 1. Introduction Gas Fast Reactor (GFR) is one of the six new systems is also studied in the framework of fusion reactors, in which this material, thanks to its high electrical

Paris-Sud XI, Université de

389

Graphene field-effect transistors based on boron nitride gate dielectrics Inanc Meric1  

E-Print Network [OSTI]

Graphene field-effect transistors based on boron nitride gate dielectrics Inanc Meric1 , Cory Dean1, 10027 Tel: (212) 854-2529, Fax: (212) 932-9421, Email: shepard@ee.columbia.edu Abstract Graphene field of graphene, as the gate dielectric. The devices ex- hibit mobility values exceeding 10,000 cm2 /V

Shepard, Kenneth

390

Compatibility/Stability Issues in the Use of Nitride Kernels in LWR TRISO Fuel  

SciTech Connect (OSTI)

The stability of the SiC layer in the presence of free nitrogen will be dependent upon the operating temperatures and resulting nitrogen pressures whether it is at High Temperature Gas-Cooled Reactor (HTGR) temperatures of 1000-1400 C (coolant design dependent) or LWR temperatures that range from 500-700 C. Although nitrogen released in fissioning will form fission product nitrides, there will remain an overpressure of nitrogen of some magnitude. The nitrogen can be speculated to transport through the inner pyrolytic carbon layer and contact the SiC layer. The SiC layer may be envisioned to fail due to resulting nitridation at the elevated temperatures. However, it is believed that these issues are particularly avoided in the LWR application. Lower temperatures will result in significantly lower nitrogen pressures. Lower temperatures will also substantially reduce nitrogen diffusion rates through the layers and nitriding kinetics. Kinetics calculations were performed using an expression for nitriding silicon. In order to further address these concerns, experiments were run with surrogate fuel particles under simulated operating conditions to determine the resulting phase formation at 700 and 1400 C.

Armstrong, Beth L [ORNL; Besmann, Theodore M [ORNL

2012-02-01T23:59:59.000Z

391

Spontaneous Spatial Alignment of Polymer Cylindrical Nanodomains on Silicon Nitride Gratings  

E-Print Network [OSTI]

a simple method to align lying-down cylindrical domains of PS-b-PMMA in the trough regions of 555 nm deepSpontaneous Spatial Alignment of Polymer Cylindrical Nanodomains on Silicon Nitride Gratings Deepak to the orientation of the grating lines and essentially spans the width of the grating trough. The proposed mechanism

Sibener, Steven

392

Measurement of the solar neutrino capture rate with gallium metal, part III  

SciTech Connect (OSTI)

The Russian-American experiment SAGE began to measure the solar neutrino capture rate with a target of gallium metal in December 1989. Measurements have continued with only a few brief interruptions since that time. In this article we present the experimental improvements in SAGE since its last published data summary in December 2001. Assuming the solar neutrino production rate was constant during the period of data collection, combined analysis of 168 extractions through December 2007 gives a capture rate of solar neutrinos with energy more than 233 keY of 65.4{sup +3.1}{sub 3.0} (stat) {sup +2.6}{sub -2.8} (syst) SNU. The weighted average of the results of all three Ga solar neUlrino experiments, SAGE, Gallex, and GNO, is now 66.1 {+-} 3.1 SNU, where statistical and systematic uncertainties have been combined in quadrature. During the recent period of data collection a new test of SAGE was made with a reactor-produced {sup 37}Ar neutrino source. The ratio of observed to calculated rates in this experiment, combined with the measured rates in the three prior {sup 51}Cr neutrino-source experiments with Ga, is 0.88 {+-} 0.05. A probable explanation for this low result is that the cross section for neutrino capture by the two lowest-lying excited states in {sup 71}Ge has been overestimated. If we assume these cross sections are zero, then the standard solar model including neutrino oscillations predicts a total capture rate in Ga in the range of 63--67 SNU with an uncertainly of about 5%, in good agreement with experiment. We derive the current value of the pp neutrino flux produced in the Sun to be {phi}{sup {circle_dot}}{sub pp} = (6.1 {+-} 0.8) x 10{sup 10}/(cm{sup 2} s), which agrees well with the flux predicted by the standard solar model. Finally, we make several tests and show that the data are consistent with the assumption that the solar neutrino production rate is constant in time.

Elliott, Steven Ray [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

393

Bulk emission of scalars by a rotating black hole  

E-Print Network [OSTI]

We study in detail the scalar-field Hawking radiation emitted into the bulk by a higher-dimensional, rotating black hole. We numerically compute the angular eigenvalues, and solve the radial equation of motion in order to find transmission factors. The latter are found to be enhanced by the angular momentum of the black hole, and to exhibit the well-known effect of superradiance. The corresponding power spectra for scalar fields show an enhancement with the number of dimensions, as in the non-rotating case. We compute the total mass loss rate of the black hole for a variety of black-hole angular momenta and bulk dimensions, and find that, in all cases, the bulk emission remains significantly smaller than the brane emission. The angular-momentum loss rate is also computed and found to have a smaller value in the bulk than on the brane. We present accurate bulk-to-brane emission ratios for a range of scenarios.

M. Casals; S. R. Dolan; P. Kanti; E. Winstanley

2008-07-17T23:59:59.000Z

394

Additive-assisted synthesis of boride, carbide, and nitride micro/nanocrystals  

SciTech Connect (OSTI)

General and simple methods for the syntheses of borides, carbides and nitrides are highly desirable, since those materials have unique physical properties and promising applications. Here, a series of boride (TiB{sub 2}, ZrB{sub 2}, NbB{sub 2}, CeB{sub 6}, PrB{sub 6}, SmB{sub 6}, EuB{sub 6}, LaB{sub 6}), carbide (SiC, TiC, NbC, WC) and nitride (TiN, BN, AlN, MgSiN{sub 2}, VN) micro/nanocrystals were prepared from related oxides and amorphous boron/active carbon/NaN{sub 3} with the assistance of metallic Na and elemental S. In-situ temperature monitoring showed that the reaction temperature could increase quickly to {approx}850 Degree-Sign C, once the autoclave was heated to 100 Degree-Sign C. Such a rapid temperature increase was attributed to the intense exothermic reaction between Na and S, which assisted the formation of borides, carbides and nitrides. The as-obtained products were characterized by XRD, SEM, TEM, and HRTEM techniques. Results in this report will greatly benefit the future extension of this approach to other compounds. - Graphical abstract: An additive-assisted approach is successfully developed for the syntheses of borides, carbides and nitrides micro/nanocrystals with the assistance of the exothermic reaction between Na and S. Highlights: Black-Right-Pointing-Pointer An additive-assisted synthesis strategy is developed for a number of borides, carbides and nitrides. Black-Right-Pointing-Pointer The reaction mechanism is demonstrated by the case of SiC nanowires. Black-Right-Pointing-Pointer The formation of SiC nanowires is initiated by the exothermic reaction of Na and S.

Chen, Bo [Key Laboratory of Colloid and Interface Chemistry (Shandong University), Ministry of Education, and Department of Chemistry, Shandong University, Jinan 250100 (China)] [Key Laboratory of Colloid and Interface Chemistry (Shandong University), Ministry of Education, and Department of Chemistry, Shandong University, Jinan 250100 (China); Yang, Lishan [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Shandong University), Ministry of Education, and School of Materials Science and Engineering, Shandong University, Jinan 250061 (China)] [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Shandong University), Ministry of Education, and School of Materials Science and Engineering, Shandong University, Jinan 250061 (China); Heng, Hua; Chen, Jingzhong; Zhang, Linfei; Xu, Liqiang [Key Laboratory of Colloid and Interface Chemistry (Shandong University), Ministry of Education, and Department of Chemistry, Shandong University, Jinan 250100 (China)] [Key Laboratory of Colloid and Interface Chemistry (Shandong University), Ministry of Education, and Department of Chemistry, Shandong University, Jinan 250100 (China); Qian, Yitai, E-mail: ytqian@sdu.edu.cn [Key Laboratory of Colloid and Interface Chemistry (Shandong University), Ministry of Education, and Department of Chemistry, Shandong University, Jinan 250100 (China)] [Key Laboratory of Colloid and Interface Chemistry (Shandong University), Ministry of Education, and Department of Chemistry, Shandong University, Jinan 250100 (China); Yang, Jian, E-mail: yangjian@sdu.edu.cn [Key Laboratory of Colloid and Interface Chemistry (Shandong University), Ministry of Education, and Department of Chemistry, Shandong University, Jinan 250100 (China)] [Key Laboratory of Colloid and Interface Chemistry (Shandong University), Ministry of Education, and Department of Chemistry, Shandong University, Jinan 250100 (China)

2012-10-15T23:59:59.000Z

395

Tunnel-injection quantum dot deep-ultraviolet light-emitting diodes with polarization-induced doping in III-nitride heterostructures  

SciTech Connect (OSTI)

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.

Verma, Jai, E-mail: jverma@nd.edu; Islam, S. M.; Protasenko, Vladimir; Kumar Kandaswamy, Prem; Xing, Huili; Jena, Debdeep [Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States)

2014-01-13T23:59:59.000Z

396

Quasiparticle theory of shear and bulk viscosities of hadronic matter  

SciTech Connect (OSTI)

A theoretical framework for the calculation of shear and bulk viscosities of hadronic matter at finite temperature is presented. The framework is based on the quasiparticle picture. It allows for an arbitrary number of hadron species with pointlike interactions, and allows for both elastic and inelastic collisions. Detailed balance is ensured. The particles have temperature-dependent masses arising from mean-field or potential effects, which maintains self-consistency between the equation of state and the transport coefficients. As an example, we calculate the shear and bulk viscosity in the linear {sigma} model. The ratio of shear viscosity to entropy density shows a minimum in the vicinity of a rapid crossover transition, whereas the ratio of bulk viscosity to entropy density shows a maximum.

Chakraborty, P.; Kapusta, J. I. [School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

2011-01-15T23:59:59.000Z

397

In situ chemical sensing in AlGaN/GaN high electron mobility transistor metalorganic chemical vapor deposition process for real-time  

E-Print Network [OSTI]

; accepted 14 June 2005; published 18 July 2005 Gallium nitride and its alloys promise to be key materials.1116/1.1993616 I. INTRODUCTION In recent years, gallium-nitride GaN - and aluminum- gallium-nitride AlGaN -based are grown at high temperatures e.g., up to 1100 °C using large concentrations of H2 carrier and NH3 N source

Rubloff, Gary W.

398

Properties of Bulk Sintered Silver As a Function of Porosity  

SciTech Connect (OSTI)

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.

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

2012-06-01T23:59:59.000Z

399

Bulk-edge correspondence for two-dimensional topological insulators  

E-Print Network [OSTI]

Topological insulators can be characterized alternatively in terms of bulk or edge properties. We prove the equivalence between the two descriptions for two-dimensional solids in the single-particle picture. We give a new formulation of the $\\mathbb{Z}_{2}$-invariant, which allows for a bulk index not relying on a (two-dimensional) Brillouin zone. When available though, that index is shown to agree with known formulations. The method also applies to integer quantum Hall systems. We discuss a further variant of the correspondence, based on scattering theory.

G. M. Graf; M. Porta

2013-03-19T23:59:59.000Z

400

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

DOE Patents [OSTI]

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.

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

2013-01-08T23:59:59.000Z

Note: This page contains sample records for the topic "bulk gallium nitride" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

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

SciTech Connect (OSTI)

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.

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

2009-05-04T23:59:59.000Z

402

E-Print Network 3.0 - arsenide oxides sr2cro3feas Sample Search...  

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

Microstructures of gallium nitride nanowires synthesized by oxide-assisted method W.S. Shi, Y... synthesized using the recently developed oxide-assisted method by laser...

403

2012 Solid-State Lighting Manufacturing R&D Workshop Presentations...  

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

Frank Cerio, Veeco Instruments Advanced Epi Tools for Gallium Nitride Light Emitting Diode Devices Vivek Agrawal, Applied Materials Driving Down HB-LED Costs:...

404

STATEMENT OF CONSIDERATIONS REQUEST BY CREE, INC. FOR AN ADVANCED...  

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

in the design and.manufacture of commercial semiconductor products utilizing silicon carbide and gallium nitride technologies. Cree states it is the owner or licensee to over 500...

405

STATEMENT OF CONSIDERATIONS REQUEST BY CREE, INC. FOR AN ADVANCED...  

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

in the design and manufacture of commercial semiconductor products utilizing silicon carbide and gallium nitride technologies. In addition Cree has more than 300 domestic patents...

406

High Temperature, High Voltage Fully Integrated Gate Driver Circuit  

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

temperature gate drive is being developed for use with future wide band gap (silicon carbide and gallium nitride) switching devices. * Universal drive that is capable of driving...

407

Sandia National Laboratories: Sandia Develops a Synthesis of...  

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

Materials Science, News, News & Events, Office of Science, Research & Capabilities, Solid-State Lighting White light-emitting diodes (LEDs) based on blue indium-gallium-nitride...

408

Diamonds are an Electronic Device's Best Friend | Department...  

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

way to combine diamond films with two other materials important for advanced devices, graphene and gallium nitride. Graphene is a rising star of the materials science world, with...

409

Categorical Exclusion Determination Form  

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

of SubMIC components, including the proprietary PolyStrata micro-coaxial transformer, Gallium Nitride integrated circuits, and Complementary Metal-Oxide Semiconductors,...

410

Characteristics of trap-filled gallium arsenide photoconductive switches used in high gain pulsed power applications  

SciTech Connect (OSTI)

The electrical properties of semi-insulating (SI) Gallium Arsenide (GaAs) have been investigated for some time, particularly for its application as a substrate in microelectronics. Of late this material has found a variety of applications other than as an isolation region between devices, or the substrate of an active device. High resistivity SI GaAs is increasingly being used in charged particle detectors and photoconductive semiconductor switches (PCSS). PCSS made from these materials operating in both the linear and non-linear modes have applications such as firing sets, as drivers for lasers, and in high impedance, low current Q-switches or Pockels cells. In the non-linear mode, it has also been used in a system to generate Ultra-Wideband (UWB) High Power Microwaves (HPM). The choice of GaAs over silicon offers the advantage that its material properties allow for fast, repetitive switching action. Furthermore photoconductive switches have advantages over conventional switches such as improved jitter, better impedance matching, compact size, and in some cases, lower laser energy requirement for switching action. The rise time of the PCSS is an important parameter that affects the maximum energy transferred to the load and it depends, in addition to other parameters, on the bias or the average field across the switch. High field operation has been an important goal in PCSS research. Due to surface flashover or premature material breakdown at higher voltages, most PCSS, especially those used in high power operation, need to operate well below the inherent breakdown voltage of the material. The lifetime or the total number of switching operations before breakdown, is another important switch parameter that needs to be considered for operation at high bias conditions. A lifetime of {approximately} 10{sup 4} shots has been reported for PCSS's used in UWB-HPM generation [5], while it has exceeded 10{sup 8} shots for electro-optic drivers. Much effort is currently being channeled in the study related to improvements of these two parameters high bias operation and lifetime improvement for switches used in pulsed power applications. The contact material and profiles are another important area of study. Although these problems are being pursued through the incorporation of different contact materials and introducing doping near contacts, it is important that the switch properties and the conduction mechanism in these switches be well understood such that the basic nature of the problems can be properly addressed. In this paper the authors report on these two basic issues related to the device operation, i.e., mechanisms for increasing the hold-off characteristics through neutron irradiation, and the analysis of transport processes at varying field conditions in trap dominated SI GaAs in order to identify the breakdown mechanism during device operation. It is expected that this study would result in a better understanding of photoconductive switches, specifically those used in high power operation.

ISLAM,N.E.; SCHAMILOGLU,E.; MAR,ALAN; LOUBRIEL,GUILLERMO M.; ZUTAVERN,FRED J.; JOSHI,R.P.

2000-05-30T23:59:59.000Z

411

Permanent magnet with MgB{sub 2} bulk superconductor  

SciTech Connect (OSTI)

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.

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)

2014-07-21T23:59:59.000Z

412

Security-Constrained Adequacy Evaluation of Bulk Power System Reliability  

E-Print Network [OSTI]

Security-Constrained Adequacy Evaluation of Bulk Power System Reliability Fang Yang, Student Member contingency selection, (b) effects analysis, and (c) reliability index computation. Effects analysis and reliability index computations. The methodology is demonstrated with the IEEE reliability test system. Index

413

Stress tensor and bulk viscosity in relativistic nuclear collisions  

E-Print Network [OSTI]

We discuss the influence of different initial conditions for the stress tensor and the effect of bulk viscosity on the expansion and cooling of the fireball created in relativistic heavy ion collisions. In particular, we explore the evolution...however, it does not significantly increase the entropy produced....

Fries, Rainer J.; Mueller, Berndt; Schaefer, Andreas.

2008-01-01T23:59:59.000Z

414

Development of Bulk Nanocrystalline Cemented Tungsten Carbide for Industrial Applicaitons  

SciTech Connect (OSTI)

This report contains detailed information of the research program entitled "Development of Bulk Nanocrystalline Cemented Tungsten Carbide Materials for Industrial Applications". The report include the processes that were developed for producing nanosized WC/Co composite powders, and an ultrahigh pressure rapid hot consolidation process for sintering of nanosized powders. The mechanical properties of consolidated materials using the nanosized powders are also reported.

Z. Zak Fang, H. Y. Sohn

2009-03-10T23:59:59.000Z

415

MORPHOLOGY DEPENDENT SHORT CIRCUIT CURRENT IN BULK HETEROJUNCTION SOLAR CELL  

E-Print Network [OSTI]

of the coupled exciton/electron/hole flow in the disordered polymer network, but also guarantees to connect kinetics appears complex and final structure is randomly interpenetrating clusters of polymer and fullerene, West Lafayette, Indiana, USA ABSTRACT Polymer based bulk heterostructure (BH) solar cell offers

Alam, Muhammad A.

416

Computing hypersurfaces which minimize surface energy plus bulk energy  

E-Print Network [OSTI]

the energy of an interface surface, where the energy might be just area, or could have a density dependent curvature associated to the energy density ; if 1 so that the surface energy is just area[Page 17] Computing hypersurfaces which minimize surface energy plus bulk energy John M. Sullivan

Sullivan, John M.

417

A COMPREHENSIVE TECHNICAL REVIEW OF THE DEMONSTRATION BULK VITRIFICATION SYSTEM  

SciTech Connect (OSTI)

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.

SCHAUS, P.S.

2006-09-29T23:59:59.000Z

418

Non-Destructive Spent Fuel Characterization with Semi-Conducting Gallium Arsinde Neutron Imaging Arrays  

SciTech Connect (OSTI)

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.

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

2002-01-30T23:59:59.000Z

419

Pulsed-ion-beam nitriding and smoothing of titanium surface in a vacuum  

SciTech Connect (OSTI)

Both nitriding and smoothing of titanium have been achieved under irradiation of intense pulsed ion beam in a vacuum of 2x10{sup -2} Pa. Applying a screening method, we find that medium ion-beam intensity and multi-shot irradiation are effective for the processing, where repetitive surface melting with limited ablation favored Ti nitride formation as well as surface smoothing. The present results demonstrate that ambient gas atoms/molecules can be efficiently incorporated in metal matrices to form compounds under the ion-beam irradiation. The finding is of great significance for extending application scope of the ion-beam technique in materials research and processing, combined with the recent success in introducing ambient gas into the processing chamber.

Zhu, X.P.; Suematsu, Hisayuki; Jiang Weihua; Yatsui, Kiyoshi; Lei, M.K. [Extreme Energy-Density Research Institute, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188 (Japan); Surface Engineering Laboratory, Department of Materials Engineering, Dalian University of Technology, Dalian 116024 (China)

2005-08-29T23:59:59.000Z

420

Phase transformations of nano-sized cubic boron nitride to white graphene and white graphite  

SciTech Connect (OSTI)

We report quantum-mechanical investigations that predict the formation of white graphene and nano-sized white graphite from the first-order phase transformations of nano-sized boron nitride thin-films. The phase transformations from the nano-sized diamond-like structure, when the thickness d?>?1.4?nm, to the energetically more stable nano-sized white graphite involve low activation energies of less than 1.0?eV. On the other hand, the diamond-like structure transforms spontaneously to white graphite when d???1.4?nm. In particular, the two-dimensional structure with single-layer boron nitride, the so-called white graphene, could be formed as a result of such transformation.

Dang, Hongli; Liu, Yingdi; Xue, Wenhua; Anderson, Ryan S.; Sewell, Cody R. [Department of Physics and Engineering Physics, The University of Tulsa, Tulsa, Oklahoma 74104 (United States); Xue, Sha; Crunkleton, Daniel W. [Department of Chemical Engineering, The University of Tulsa, Tulsa, Oklahoma 74104 (United States); Institute of Alternate Energy, The University of Tulsa, Tulsa, Oklahoma 74104 (United States); Shen, Yaogen [Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Kowloon (Hong Kong); Wang, Sanwu, E-mail: sanwu-wang@utulsa.edu [Department of Physics and Engineering Physics, The University of Tulsa, Tulsa, Oklahoma 74104 (United States); Institute of Alternate Energy, The University of Tulsa, Tulsa, Oklahoma 74104 (United States)

2014-03-03T23:59:59.000Z

Note: This page contains sample records for the topic "bulk gallium nitride" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Nondestructive evaluation of silicon-nitride ceramic valves from engine duration test.  

SciTech Connect (OSTI)

In this study, we investigated impact and wear damage in silicon-nitride ceramic valves that were subjected to an engine duration test in a natural-gas engine. A high-speed automated laser-scattering system was developed for the nondestructive evaluation (NDE) of 10 SN235P silicon-nitride valves. The NDE system scans the entire valve surface and generates a two-dimensional scattering image that is used to identify location, size and relative severity of subsurface damage in the valves. NED imaging data were obtained at before and at 100 and 500 hours of the engine duration test. The NDE data were analyzed and compared with surface photomicrographs. Wear damage was found in the impact surface of all valves, expecially for exhaust valves. However, the NDE examination did not detect subsurface damage such as cracks or spalls in these engine-tested valves.

Sun, J. G.; Trethewey, J. S.; Vanderspiegle, N. N.; Jensen, J. A.; Nuclear Engineering Division; Caterpillar, Inc.

2008-01-01T23:59:59.000Z

422

Thermal transport in boron nitride nanotorus—towards a nanoscopic thermal shield  

SciTech Connect (OSTI)

Nanotori, or nanorings, are topological variants of nanotubes and are conceived to have different properties from their tubular form. In this study, the toroidal arrangement of boron nitride is introduced. Using classical molecular dynamics simulations, the thermal behaviour (thermal conductivity and thermal stability) of the boron nitride nanotorus and its relationship with the structural characteristics are investigated. Its circumferential thermal rectification strength displays a linear dependence on the bending coefficient of the nanostructure. Surface kinks are relatively inconsequential on its circumferential mode of conduction, as compared to its axial sense. The circumferential conductivity in the diffusive regime is calculated to be approximately 10?W/m K, while the axial conductivity is more than tenfold of this value. All nanotori with different toroidal characters show excellent thermal stability at extremely high temperatures approaching 3400?K. With consideration to its favourable properties, a thermal shield made up of a parallel row of nanotori is proposed as a nanoscale thermal insulation device.

Loh, G. C., E-mail: jgloh@mtu.edu [Institute of High Performance Computing, 1 Fusionopolis Way, 16-16 Connexis, Singapore 138632 (Singapore); Department of Physics, Michigan Technological University, Houghton, Michigan 49931 (United States); Baillargeat, D. [CNRS-International-NTU-Thales Research Alliance (CINTRA), 50 Nanyang Drive, Singapore 637553 (Singapore)

2013-11-14T23:59:59.000Z

423

Effects of plasma-deposited silicon nitride passivation on the radiation hardness of CMOS integrated circuits  

SciTech Connect (OSTI)

The use of plasma-deposited silicon nitride as a final passivation over metal-gate CMOS integrated circuits degrades the radiation hardness of these devices. The hardness degradation is manifested by increased radiation-induced threshold voltage shifts caused principally by the charging of new interface states and, to a lesser extent, by the trapping of holes created upon exposure to ionizing radiation. The threshold voltage shifts are a strong function of the deposition temperature, and show very little dependence on thickness for films deposited at 300/sup 0/C. There is some correlation between the threshold voltage shifts and the hydrogen content of the PECVD silicon nitride films used as the final passivation layer as a function of deposition temperature. The mechanism by which the hydrogen contained in these films may react with the Si/SiO/sub 2/ interface is not clear at this point.

Clement, J. J.

1980-01-01T23:59:59.000Z

424

Heteroepitaxy of group IV-VI nitrides by atomic layer deposition  

SciTech Connect (OSTI)

Heteroepitaxial growth of selected group IV-VI nitrides on various orientations of sapphire (?-Al{sub 2}O{sub 3}) is demonstrated using atomic layer deposition. High quality, epitaxial films are produced at significantly lower temperatures than required by conventional deposition methods. Characterization of electrical and superconducting properties of epitaxial films reveals a reduced room temperature resistivity and increased residual resistance ratio for films deposited on sapphire compared to polycrystalline samples deposited concurrently on fused quartz substrates.

Klug, Jeffrey A., E-mail: jklug@anl.gov; Groll, Nickolas R.; Pellin, Michael J.; Proslier, Thomas, E-mail: prolier@anl.gov [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)] [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Becker, Nicholas G.; Cao, Chaoyue; Zasadzinski, John F. [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States) [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics, Illinois Institute of Technology, Chicago, Illinois 60616 (United States); Weimer, Matthew S. [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States) [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Chemistry, Illinois Institute of Technology, Chicago, Illinois 60616 (United States)

2013-11-18T23:59:59.000Z

425

Ab initio study of phase transition of boron nitride between zinc-blende and rhombohedral structures  

SciTech Connect (OSTI)

Boron nitride has polymorphs such as zinc-blende (c-BN), wurtzite (w-BN), rhombohedral (r-BN), and graphite-like (h-BN) forms. We simulate the direct conversion of r-BN to c-BN through electronic excitation. In our calculation, the conversion is made possible by increasing the hole concentration to over 0.06/atom. This conversion should be experimentally possible by hole-doping via an electric double layer transistor (EDLT) or capacitor.

Nishida, S.; Funashima, H.; Sato, K.; Katayama-Yoshida, H. [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan)

2013-12-04T23:59:59.000Z

426

Amber light-emitting diode comprising a group III-nitride nanowire active region  

DOE Patents [OSTI]

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.

Wang, George T.; Li, Qiming; Wierer, Jr., Jonathan J.; Koleske, Daniel

2014-07-22T23:59:59.000Z

427

Integrated rig for the production of boron nitride nanotubes via the pressurized vapor-condenser method  

DOE Patents [OSTI]

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.

Smith, Michael W; Jordan, Kevin C

2014-03-25T23:59:59.000Z

428

An electrochemical method suitable for preparing nine metal-nitride powders  

SciTech Connect (OSTI)

We present an electrochemical method that is suitable for the preparation of metal-nitride ceramic materials that is both simple and general. We begin with a single-compartment electrochemical cell containing suitable metal (M) anodes and cathodes (M=Al, Mo, Nb, Ni, Ti, V, W, Zn, or Zr) and a NH{sub 3}/NH{sub 4}X (X=Br or Cl) electrolyte solution. Application of a sufficiently high voltage results in oxidation and dissolution of M to M{sup n+} at the anode and reduction of NH{sub 3} to NH{sub 2}- at the cathode. When M=Al, this results in formation of an insoluble inorganic polymer, which can subsequently be calcined above 600{degrees}C to yield phase-pure AlN. For some of the other metals, a simple ammoniated metal ion is formed at the anode, but calcination of this material also leads to the corresponding metal nitride. The phases and morphologies of the powders depends strongly on the calcining conditions. The important point is that this method is general for the preparation of metal-nitride powders even though the pathway that leads to the powders is metal-dependent. This talk will focus primarily on the preparation of AlN, which is an important packaging material for the electronics industry, and NbN, which is a superconductor (T{sub c}{approximately}17 K) with important technological applications.

Wade, T.; Crooks, R.M. [Texas A& M Univ., College Station, TX (United States)

1995-12-31T23:59:59.000Z

429

Transmission electron microscopy investigation of acicular ferrite precipitation in {gamma}'-Fe{sub 4}N nitride  

SciTech Connect (OSTI)

Acicular-shaped crystals precipitate from {gamma}'-Fe{sub 4}N nitride in an iron-nitrogen alloy and were identified by electron microdiffraction as {alpha}-ferrite. Acicular ferrite develops both the Nishiyama-Wassermann and the Kurdjumov-Sachs orientation relationships with {gamma}'-Fe{sub 4}N nitride. These orientation relationships were discussed in terms of the symmetry theory. The driving force for acicular ferrite formation was related to the increasing nitrogen content of {gamma}'-Fe{sub 4}N, in equilibrium with {alpha}-ferrite, with decreasing temperature. The passage from lamellar to acicular structure in Fe-N system was proposed. - Research Highlights: {yields} Acicular crystals precipitate from pearlitic{gamma}'-Fe{sub 4}N nitride in an iron-nitrogen alloy and were identified by electron microdiffraction as acicular ferrite. {yields} The crystal structure, orientation relationships with the matrix and morphologies of acicular ferrite, were studied by transmission electron microscopy. {yields} The driving force for the formation of acicular ferrite is related to the temperature dependence of nitrogen content of {gamma}'-Fe{sub 4}N, in equilibrium with ferrite. {yields} The passage from the pearlitic structure to the acicular structure in the present iron-nitrogen alloy was proposed.

Xiong, X.C., E-mail: xiaochuan.xiong@sjtu.edu.cn [Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Institut Jean Lamour, UMR 7198 CNRS, Nancy-Universite, UPV-Metz, Ecole des Mines de Nancy, Parc de Saurupt CS 14234, F-54042 Nancy Cedex (France); Redjaimia, A. [Institut Jean Lamour, UMR 7198 CNRS, Nancy-Universite, UPV-Metz, Ecole des Mines de Nancy, Parc de Saurupt CS 14234, F-54042 Nancy Cedex (France); Goune, M. [Institut Jean Lamour, UMR 7198 CNRS, Nancy-Universite, UPV-Metz, Ecole des Mines de Nancy, Parc de Saurupt CS 14234, F-54042 Nancy Cedex (France); ArcelorMittal SA, Voie Romaine, BP 30320, F-57283 Maizieres-les-Metz (France)

2010-11-15T23:59:59.000Z

430

MOCVD synthesis of group III-nitride heterostructure nanowires for solid-state lighting.  

SciTech Connect (OSTI)

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.

Wang, George T.; Creighton, James Randall; Talin, Albert Alec

2006-11-01T23:59:59.000Z

431

Behavior of molybdenum nitrides as materials for electrochemical capacitors: Comparison with ruthenium oxide  

SciTech Connect (OSTI)

Ruthenium oxide (RuO{sub 2}), formed as a thin film on a Ru or Ti metal substrate, exhibits a large specific (cm{sup {minus}2}) and almost constant, electrochemical capacitance over a 1.35 V range in aqueous H{sub 2}SO{sub 4}. This behavior has led to its investigation and use as a material for fabrication of supercapacitor devices. However, its cost has encouraged search for other materials exhibiting similar behavior. Work reported in the present paper evaluates two nitrides of Mo, Mo{sub 2}N and MoN, as substitutes for RuO{sub 2}. It is shown that very similar capacitance behavior to that of RuO{sub 2} films arises, e.g., in cyclic voltammetry and dc charging curves; in the former, almost mirror-image anodic and cathodic current-response profiles, characteristic of a capacitor, arise. However, the nitride materials have a substantially smaller voltage operating range of only some 0.7 V due to electrochemical decomposition above ca. 0.7 V vs. RHE. This limits their usefulness as a substitute for RuO{sub 2}. Of interest is that the nitride films exhibit potential-decay and potential-recovery on open circuit after respective charge and forced discharge. The decay and recovery processes are logarithmic in time, indicating the role of internal faradaic charge redistribution processes.

Liu, T.C.; Pell, W.G.; Conway, B.E. [Univ. of Ottawa, Ontario (Canada). Dept. of Chemistry; Roberson, S.L. [North Carolina State Univ., Raleigh, NC (United States). Dept. of Materials Science and Engineering

1998-06-01T23:59:59.000Z

432

Analytical and experimental evaluation of joining silicon carbide to silicon carbide and silicon nitride to silicon nitride for advanced heat engine applications Phase 2. Final report  

SciTech Connect (OSTI)

The purpose of joining, Phase 2 was to develop joining technologies for HIP`ed Si{sub 3}N{sub 4} with 4wt% Y{sub 2}O{sub 3} (NCX-5101) and for a siliconized SiC (NT230) for various geometries including: butt joins, curved joins and shaft to disk joins. In addition, more extensive mechanical characterization of silicon nitride joins to enhance the predictive capabilities of the analytical/numerical models for structural components in advanced heat engines was provided. Mechanical evaluation were performed by: flexure strength at 22 C and 1,370 C, stress rupture at 1,370 C, high temperature creep, 22 C tensile testing and spin tests. While the silicon nitride joins were produced with sufficient integrity for many applications, the lower join strength would limit its use in the more severe structural applications. Thus, the silicon carbide join quality was deemed unsatisfactory to advance to more complex, curved geometries. The silicon carbide joining methods covered within this contract, although not entirely successful, have emphasized the need to focus future efforts upon ways to obtain a homogeneous, well sintered parent/join interface prior to siliconization. In conclusion, the improved definition of the silicon carbide joining problem obtained by efforts during this contract have provided avenues for future work that could successfully obtain heat engine quality joins.

Sundberg, G.J.; Vartabedian, A.M.; Wade, J.A.; White, C.S. [Norton Co., Northboro, MA (United States). Advanced Ceramics Div.

1994-10-01T23:59:59.000Z

433

Method of fabricating an optoelectronic device having a bulk heterojunction  

DOE Patents [OSTI]

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.

Shtein, Max (Ann Arbor, MI); Yang, Fan (Princeton, NJ); Forrest, Stephen R. (Princeton, NJ)

2008-10-14T23:59:59.000Z

434

Bulk-Brane Interaction and Holographic Dark Energy  

E-Print Network [OSTI]

In this paper we consider the bulk-brane interaction to obtain the equation of state for the holographic energy density in non-flat universe enclosed by the event horizon measured from the sphere of horizon named $L$. We assumes that the cold dark matter energy density on the brane is conserved, but the holographic dark energy density on the brane is not conserved due to brane-bulk energy exchange. Our calculation show, taking $\\Omega_{\\Lambda}=0.73$ for the present time, the lower bound of $w_{\\rm \\Lambda}^{eff}$ is -0.9. This implies that one can not generate phantom-like equation of state from an interacting holographic dark energy model in non-flat universe.

M R Setare

2006-12-14T23:59:59.000Z

435

Gravity-related spontaneous collapse in bulk matter  

E-Print Network [OSTI]

In the DP-model, gravity-related spontaneous wave function collapses suppress undesirable Schr\\"odinger Cat states. We derive the equations of the model for the hydrodynamic-elastic (acoustic) modes in a bulk. Two particular features are discussed: the universal dominance of spontaneous collapses at large wavelengths, and the reduction of spontaneous heating by a slight refinement of the DP-model.

Lajos Diósi

2014-04-26T23:59:59.000Z

436

Comparison of bulk- and surface-micromachined pressure sensors  

SciTech Connect (OSTI)

Two piezoresistive micromachined pressure sensors were compared: a commercially available bulk-micromachined (BM) pressure sensor and an experimental surface-micromachined (SM) pressure sensor. While the SM parts had significantly smaller die sizes, they were outperformed in most areas by the BM parts. This was due primarily to the smaller piezoresistive gauge factor in the polysilicon piezoresistors in the SM parts compared to the single crystal strain gauge used in the BM parts.

Eaton, W.P.; Smith, J.H. [Sandia National Labs., Albuquerque, NM (United States); Monk, D.J.; O`Brien, G.; Miller, T.F. [Motorola, Phoenix, AZ (United States)

1998-08-01T23:59:59.000Z

437

RAPID/BulkTransmission/Alaska | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia: EnergyPotentialUrbanUtilityScalePVCapacityPulaski County, Kentucky:County,Quogue isRAPID/BulkTransmission/Alaska

438

RAPID/BulkTransmission/Hawaii | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia: EnergyPotentialUrbanUtilityScalePVCapacityPulaski County,RAPID/BulkTransmission/Hawaii < RAPID‎ |

439

RAPID/BulkTransmission/Idaho | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia: EnergyPotentialUrbanUtilityScalePVCapacityPulaski County,RAPID/BulkTransmission/Hawaii < RAPID‎

440

RAPID/BulkTransmission/Land Access | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia: EnergyPotentialUrbanUtilityScalePVCapacityPulaski County,RAPID/BulkTransmission/Hawaii < RAPID‎Land Access

Note: This page contains sample records for the topic "bulk gallium nitride" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

RAPID/BulkTransmission/Land Use | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia: EnergyPotentialUrbanUtilityScalePVCapacityPulaski County,RAPID/BulkTransmission/Hawaii < RAPID‎Land

442

RAPID/BulkTransmission/Montana | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia: EnergyPotentialUrbanUtilityScalePVCapacityPulaski County,RAPID/BulkTransmission/Hawaii <

443

RAPID/BulkTransmission/Nevada | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia: EnergyPotentialUrbanUtilityScalePVCapacityPulaski County,RAPID/BulkTransmission/Hawaii <Nevada < RAPID‎

444

RAPID/BulkTransmission/New Mexico | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia: EnergyPotentialUrbanUtilityScalePVCapacityPulaski County,RAPID/BulkTransmission/Hawaii <Nevada <

445

RAPID/BulkTransmission/Oregon | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia: EnergyPotentialUrbanUtilityScalePVCapacityPulaski County,RAPID/BulkTransmission/Hawaii <Nevada

446

RAPID/BulkTransmission/Power Plant | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia: EnergyPotentialUrbanUtilityScalePVCapacityPulaski County,RAPID/BulkTransmission/Hawaii

447

RAPID/BulkTransmission/Transmission Siting & Interconnection | Open Energy  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia: EnergyPotentialUrbanUtilityScalePVCapacityPulaskiRAPID/BulkTransmission/Texas < RAPID‎ |

448

RAPID/BulkTransmission/Utah | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia: EnergyPotentialUrbanUtilityScalePVCapacityPulaskiRAPID/BulkTransmission/Texas < RAPID‎

449

RAPID/BulkTransmission/Washington | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia: EnergyPotentialUrbanUtilityScalePVCapacityPulaskiRAPID/BulkTransmission/Texas <

450

RAPID/BulkTransmission/Water Use | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia: EnergyPotentialUrbanUtilityScalePVCapacityPulaskiRAPID/BulkTransmission/Texas

451

Bulk viscous matter-dominated Universes: asymptotic properties  

SciTech Connect (OSTI)

By means of a combined use of the type Ia supernovae and H(z) data tests, together with the study of the asymptotic properties in the equivalent phase space — through the use of the dynamical systems tools — we demonstrate that the bulk viscous matter-dominated scenario is not a good model to explain the accepted cosmological paradigm, at least, under the parametrization of bulk viscosity considered in this paper. The main objection against such scenarios is the absence of conventional radiation and matter-dominated critical points in the phase space of the model. This entails that radiation and matter dominance are not generic solutions of the cosmological equations, so that these stages can be implemented only by means of unique and very specific initial conditions, i. e., of very unstable particular solutions. Such a behavior is in marked contradiction with the accepted cosmological paradigm which requires of an earlier stage dominated by relativistic species, followed by a period of conventional non-relativistic matter domination, during which the cosmic structure we see was formed. Also, we found that the bulk viscosity is positive just until very late times in the cosmic evolution, around z < 1. For earlier epochs it is negative, been in tension with the local second law of thermodynamics.

Avelino, Arturo [Departamento de Física, Campus León, Universidad de Guanajuato, León, Guanajuato (Mexico); García-Salcedo, Ricardo [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada - Legaria del IPN, México D.F. (Mexico); Gonzalez, Tame [Departamento de Ingeniería Civil, División de Ingeniería, Universidad de Guanajuato, Guanajuato (Mexico); Nucamendi, Ulises [Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio C-3, Ciudad Universitaria, CP. 58040 Morelia, Michoacán (Mexico); Quiros, Israel, E-mail: avelino@fisica.ugto.mx, E-mail: rigarcias@ipn.mx, E-mail: tamegc72@gmail.com, E-mail: ulises@ifm.umich.mx, E-mail: iquiros6403@gmail.com [Departamento de Matemáticas, Centro Universitario de Ciencias Exactas e Ingenierías (CUCEI), Corregidora 500 S.R., Universidad de Guadalajara, 44420 Guadalajara, Jalisco (Mexico)

2013-08-01T23:59:59.000Z

452

Standard practice for bulk sampling of liquid uranium hexafluoride  

E-Print Network [OSTI]

1.1 This practice covers methods for withdrawing representative samples of liquid uranium hexafluoride (UF6) from bulk quantities of the material. Such samples are used for determining compliance with the applicable commercial specification, for example Specification C787 and Specification C996. 1.2 It is assumed that the bulk liquid UF6 being sampled comprises a single quality and quantity of material. This practice does not address any special additional arrangements that might be required for taking proportional or composite samples, or when the sampled bulk material is being added to UF6 residues already in a container (“heels recycle”). 1.3 The number of samples to be taken, their nominal sample weight, and their disposition shall be agreed upon between the parties. 1.4 The scope of this practice does not include provisions for preventing criticality incidents. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of th...

American Society for Testing and Materials. Philadelphia

2001-01-01T23:59:59.000Z

453

Bulk Viscosity and Cavitation in Boost-Invariant Hydrodynamic Expansion  

E-Print Network [OSTI]

We solve second order relativistic hydrodynamics equations for a boost-invariant 1+1-dimensional expanding fluid with an equation of state taken from lattice calculations of the thermodynamics of strongly coupled quark-gluon plasma. We investigate the dependence of the energy density as a function of proper time on the values of the shear viscosity, the bulk viscosity, and second order coefficients, confirming that large changes in the values of the latter have negligible effects. Varying the shear viscosity between zero and a few times s/(4 pi), with s the entropy density, has significant effects, as expected based on other studies. Introducing a nonzero bulk viscosity also has significant effects. In fact, if the bulk viscosity peaks near the crossover temperature Tc to the degree indicated by recent lattice calculations in QCD without quarks, it can make the fluid cavitate -- falling apart into droplets. It is interesting to see a hydrodynamic calculation predicting its own breakdown, via cavitation, at the temperatures where hadronization is thought to occur in ultrarelativistic heavy ion collisions.

Krishna Rajagopal; Nilesh Tripuraneni

2010-02-16T23:59:59.000Z

454

Boron nitride formation on magnesium studied by ab initio calculations S. Riikonen,1 A. S. Foster,1,2 A. V. Krasheninnikov,1,3 and R. M. Nieminen1,*  

E-Print Network [OSTI]

Boron nitride formation on magnesium studied by ab initio calculations S. Riikonen,1 A. S. Foster,1 of the art method for producing boron nitride nanotubes in which magnesium has been speculated to act boron and nitrogen containing molecules. We observe that magnesium promotes boron-nitride BN molecule

Krasheninnikov, Arkady V.

455

Power mixture and green body for producing silicon nitride base articles of high fracture toughness and strength  

DOE Patents [OSTI]

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

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

1991-09-17T23:59:59.000Z

456

Effects of bulk charged impurities on the bulk and surface transport in three-dimensional topological insulators  

SciTech Connect (OSTI)

In the three-dimensional topological insulator (TI), the physics of doped semiconductors exists literally side-by-side with the physics of ultrarelativistic Dirac fermions. This unusual pairing creates a novel playground for studying the interplay between disorder and electronic transport. In this mini-review, we focus on the disorder caused by the three-dimensionally distributed charged impurities that are ubiquitous in TIs, and we outline the effects it has on both the bulk and surface transport in TIs. We present self-consistent theories for Coulomb screening both in the bulk and at the surface, discuss the magnitude of the disorder potential in each case, and present results for the conductivity. In the bulk, where the band gap leads to thermally activated transport, we show how disorder leads to a smaller-than-expected activation energy that gives way to variable-range hopping at low temperatures. We confirm this enhanced conductivity with numerical simulations that also allow us to explore different degrees of impurity compensation. For the surface, where the TI has gapless Dirac modes, we present a theory of disorder and screening of deep impurities, and we calculate the corresponding zero-temperature conductivity. We also comment on the growth of the disorder potential in passing from the surface of the TI into the bulk. Finally, we discuss how the presence of a gap at the Dirac point, introduced by some source of time-reversal symmetry breaking, affects the disorder potential at the surface and the mid-gap density of states.

Skinner, B.; Chen, T.; Shklovskii, B. I., E-mail: shklovsk@physics.spa.umn.edu [University of Minnesota, Fine Theoretical Physics Institute (United States)

2013-09-15T23:59:59.000Z

457

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)

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.

McGuiggan, M.F.; Kuch, P.L.

1984-05-08T23:59:59.000Z

458

Published in 'Silicon Carbide, III-Nitrides and Related Materials', Year: 1998, pp: 829-832 Periodical: Materials Science Forum Vols. 264-268  

E-Print Network [OSTI]

Published in 'Silicon Carbide, III-Nitrides and Related Materials', Year: 1998, pp: 829@scientific.net © 1998 by Trans Tech Publications Ltd., Switzerland, http://www.ttp.net #12;Published in 'Silicon Carbide Publications Ltd., Switzerland, http://www.ttp.net #12;Published in 'Silicon Carbide, III-Nitrides and Related

Steckl, Andrew J.

459

Published in 'Silicon Carbide, III-Nitrides and Related Materials', Year: 1998, pp: 1149-1152 Periodical: Materials Science Forum Vols. 264-268  

E-Print Network [OSTI]

Published in 'Silicon Carbide, III-Nitrides and Related Materials', Year: 1998, pp: 1149@scientific.net © 1998 by Trans Tech Publications Ltd., Switzerland, http://www.ttp.net #12;Published in 'Silicon Carbide Publications Ltd., Switzerland, http://www.ttp.net #12;Published in 'Silicon Carbide, III-Nitrides and Related

Steckl, Andrew J.

460

Aluminum Nitride Thin Films on Titanium for Piezoelectric MEMS Applications Seth Boeshore, Emily Parker, Vanni Lughi, Noel C. MacDonald  

E-Print Network [OSTI]

Aluminum Nitride Thin Films on Titanium for Piezoelectric MEMS Applications Seth Boeshore, Emily Parker, Vanni Lughi, Noel C. MacDonald University of California, Santa Barbara Highly­textured aluminum, biocompatibility, and high fracture toughness. As a piezoelectric ceramic, aluminum nitride is compatible

MacDonald, Noel C.

Note: This page contains sample records for the topic "bulk gallium nitride" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

The near-edge structure in energy-loss spectroscopy: many-electron and magnetic effects in transition metal nitrides and carbides  

E-Print Network [OSTI]

in transition metal nitrides and carbides This article has been downloaded from IOPscience. Please scroll down-loss spectroscopy: many-electron and magnetic effects in transition metal nitrides and carbides A T Paxton, M van energies are systematically overestimated by 4.22 ± 0.44 eV in twelve transition metal carbides

Paxton, Anthony T.

462

GaN-Ready Aluminum Nitride Substrates for Cost-Effective, Very Low Dislocation Density III-Nitride LED's  

SciTech Connect (OSTI)

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.

Sandra Schujman; Leo Schowalter

2010-10-15T23:59:59.000Z

463

Risk-based Maintenance Allocation and Scheduling for Bulk Electric Power Transmission System Equipment  

E-Print Network [OSTI]

most state of the art reliability centered maintenance (RCM) approaches, but it also accounts equipment, maintenance, reliability, risk, security, optimization 1.Introduction Maintenance of bulk1 Risk-based Maintenance Allocation and Scheduling for Bulk Electric Power Transmission System

464

Notes 10. A thermohydrodynamic bulk-flow model for fluid film bearings  

E-Print Network [OSTI]

The complete set of bulk-flow equations for the analysis of turbulent flow fluid film bearings. Importance of thermal effects in process fluid applications. A CFD method for solution of the bulk-flow equations....

San Andres, Luis

2009-01-01T23:59:59.000Z

465

Characterization of Surface and Bulk Nitrates of ?-Al2O3...  

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

Surface and Bulk Nitrates of ?-Al2O3-Supported Alkaline Earth Oxides using Density Functional Theory. Characterization of Surface and Bulk Nitrates of ?-Al2O3-Supported...

466

Analysis and forecast of the capesize bulk carriers shipping market using Artificial Neural Networks  

E-Print Network [OSTI]

Investing in the bulk carrier market constitutes a rather risky investment due to the volatility of the bulk carrier freight rates. In this study it is attempted to uncover the benefits of using Artificial Neural Networks ...

Voudris, Athanasios V

2006-01-01T23:59:59.000Z

467

Corrosion of, and cellular responses to MgZnCa bulk metallic glasses Xuenan Gu a  

E-Print Network [OSTI]

Corrosion of, and cellular responses to Mg­Zn­Ca bulk metallic glasses Xuenan Gu a , Yufeng Zheng a: Magnesium alloy Bulk metallic glass Mechanical property Corrosion Cytotoxicity a b s t r a c t Mg­Zn­Ca bulk, mechanical testing, corrosion and cytotoxicity tests. It was found that the Mg66Zn30Ca4 sample presents

Zheng, Yufeng

468

Identification of Avalanche Precursors by Acoustic Probing in the Bulk of Tilted Granular Layers  

E-Print Network [OSTI]

Identification of Avalanche Precursors by Acoustic Probing in the Bulk of Tilted Granular Layers M simultaneously caracterize precursors on the free surface with an optical method and in the bulk with acoustic to probe rearrangements in the bulk of the granular material. A linear method can also be used provided

Paris-Sud XI, Université de

469

Laboratory Directed Research and Development (LDRD) on Mono-uranium Nitride Fuel Development for SSTAR and Space Applications  

SciTech Connect (OSTI)

The US National Energy Policy of 2001 advocated the development of advanced fuel and fuel cycle technologies that are cleaner, more efficient, less waste-intensive, and more proliferation resistant. The need for advanced fuel development is emphasized in on-going DOE-supported programs, e.g., Global Nuclear Energy Initiative (GNEI), Advanced Fuel Cycle Initiative (AFCI), and GEN-IV Technology Development. The Directorates of Energy & Environment (E&E) and Chemistry & Material Sciences (C&MS) at Lawrence Livermore National Laboratory (LLNL) are interested in advanced fuel research and manufacturing using its multi-disciplinary capability and facilities to support a design concept of a small, secure, transportable, and autonomous reactor (SSTAR). The E&E and C&MS Directorates co-sponsored this Laboratory Directed Research & Development (LDRD) Project on Mono-Uranium Nitride Fuel Development for SSTAR and Space Applications. In fact, three out of the six GEN-IV reactor concepts consider using the nitride-based fuel, as shown in Table 1. SSTAR is a liquid-metal cooled, fast reactor. It uses nitride fuel in a sealed reactor vessel that could be shipped to the user and returned to the supplier having never been opened in its long operating lifetime. This sealed reactor concept envisions no fuel refueling nor on-site storage of spent fuel, and as a result, can greatly enhance proliferation resistance. However, the requirement for a sealed, long-life core imposes great challenges to research and development of the nitride fuel and its cladding. Cladding is an important interface between the fuel and coolant and a barrier to prevent fission gas release during normal and accidental conditions. In fabricating the nitride fuel rods and assemblies, the cladding material should be selected based on its the coolant-side corrosion properties, the chemical/physical interaction with the nitride fuel, as well as their thermal and neutronic properties. The US NASA space reactor, the SP-100 was designed to use mono-uranium nitride fuel. Although the SP-100 reactor was not commissioned, tens of thousand of nitride fuel pellets were manufactured and lots of them, cladded in Nb-1-Zr had been irradiated in fast test reactors (FFTF and EBR-II) with good irradiation results. The Russian Naval submarines also use nitride fuel with stainless steel cladding (HT-9) in Pb-Bi coolant. Although the operating experience of the Russian submarine is not readily available, such combination of fuel, cladding and coolant has been proposed for a commercial-size liquid-metal cooled fast reactor (BREST-300). Uranium mono-nitride fuel is studied in this LDRD Project due to its favorable properties such as its high actinide density and high thermal conductivity. The thermal conductivity of mono-nitride is 10 times higher than that of oxide (23 W/m-K for UN vs. 2.3 W/m-K for UO{sub 2} at 1000 K) and its melting temperature is much higher than that of metal fuel (2630 C for UN vs. 1132 C for U metal). It also has relatively high actinide density, (13.51 gU/cm{sup 3} in UN vs. 9.66 gU/cm{sup 3} in UO{sub 2}) which is essential for a compact reactor core design. The objective of this LDRD Project is to: (1) Establish a manufacturing capability for uranium-based ceramic nuclear fuel, (2) Develop a computational capability to analyze nuclear fuel performance, (3) Develop a modified UN-based fuel that can support a compact long-life reactor core, and (4) Collaborate with the Nuclear Engineering Department of UC Berkeley on nitride fuel reprocessing and disposal in a geologic repository.

Choi, J; Ebbinghaus, B; Meiers, T; Ahn, J

2006-02-09T23:59:59.000Z

470

Role of silicon excess in Er-doped silicon-rich nitride light emitting devices at 1.54??m  

SciTech Connect (OSTI)

Erbium-doped silicon-rich nitride electroluminescent thin-films emitting at 1.54??m have been fabricated and integrated within a metal-oxide-semiconductor structure. By gradually varying the stoichiometry of the silicon nitride, we uncover the role of silicon excess on the optoelectronic properties of devices. While the electrical transport is mainly enabled in all cases by Poole-Frenkel conduction, power efficiency and conductivity are strongly altered by the silicon excess content. Specifically, the increase in silicon excess remarkably enhances the conductivity and decreases the charge trapping; however, it also reduces the power efficiency. The main excitation mechanism of Er{sup 3+} ions embedded in silicon-rich nitrides is discussed. The optimum Si excess that balances power efficiency, conductivity, and charge trapping density is found to be close to 16%.

Ramírez, J. M., E-mail: jmramirez@el.ub.edu; Berencén, Y.; Garrido, B. [MIND-IN2UB, Department Electrònica, Universitat de Barcelona, Martí i Franquès 1, Barcelona 08028 (Spain); Cueff, S. [Institut des Nanotechnologies de Lyon, École Centrale de Lyon, Écully 69134 (France); Labbé, C. [Centre de Recherche sur les Ions, les Matériaux et la Photonique (CIMAP), UMR 6252 CNRS/CEA/Ensicaen/UCBN, Caen 14050 (France)

2014-08-28T23:59:59.000Z

471

Photon self-induced spin-to-orbital conversion in a terbium-gallium-garnet crystal at high laser power  

SciTech Connect (OSTI)

In this paper, we present experimental evidence of a third-order nonlinear optical process, self-induced spin-to-orbital conversion (SISTOC) of the photon angular momentum. This effect is the physical mechanism at the origin of the depolarization of very intense laser beams propagating in isotropic materials. The SISTOC process, like self-focusing, is triggered by laser heating leading to a radial temperature gradient in the medium. In this work we tested the occurrence of SISTOC in a terbium-gallium-garnet rod for an impinging laser power of about 100 W. To study the SISTOC process we used different techniques: polarization analysis, interferometry, and tomography of the photon orbital angular momentum. Our results confirm, in particular, that the apparent depolarization of the beam is due to the occurrence of maximal entanglement between the spin and orbital angular momentum of the photons undergoing the SISTOC process. This explanation of the true nature of the depolarization mechanism could be of some help in finding novel methods to reduce or to compensate for this usually unwanted depolarization effect in all cases where very high laser power and good beam quality are required.

Mosca, S.; De Rosa, R.; Milano, L. [Dipartimento di Scienze Fisiche, Universita di Napoli 'Federico II', Complesso Universitario di Monte S. Angelo, 80126 Napoli (Italy); INFN Sezione di Napoli, Complesso Universitario di Monte S. Angelo, 80126 Napoli (Italy); Canuel, B.; Genin, E. [EGO, European Gravitational Observatory, Via E. Amaldi, 56021 S. Stefano a Macerata, Cascina (Italy); Karimi, E. [Dipartimento di Scienze Fisiche, Universita di Napoli 'Federico II', Complesso Universitario di Monte S. Angelo, 80126 Napoli (Italy); Piccirillo, B.; Santamato, E. [Dipartimento di Scienze Fisiche, Universita di Napoli 'Federico II', Complesso Universitario di Monte S. Angelo, 80126 Napoli (Italy); CNISM-Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, Napoli (Italy); Marrucci, L. [Dipartimento di Scienze Fisiche, Universita di Napoli 'Federico II', Complesso Universitario di Monte S. Angelo, 80126 Napoli (Italy); CNR-INFM Coherentia, Complesso Universitario di Monte S. Angelo, 80126 Napoli (Italy)

2010-10-15T23:59:59.000Z

472

CO{sub 2} laser-based dispersion interferometer utilizing orientation-patterned gallium arsenide for plasma density measurements  

SciTech Connect (OSTI)

A dispersion interferometer based on the second-harmonic generation of a carbon dioxide laser in orientation-patterned gallium arsenide has been developed for measuring electron density in plasmas. The interferometer includes two nonlinear optical crystals placed on opposite sides of the plasma. This instrument has been used to measure electron line densities in a pulsed radio-frequency generated argon plasma. A simple phase-extraction technique based on combining measurements from two successive pulses of the plasma has been used. The noise-equivalent line density was measured to be 1.7 × 10{sup 17} m{sup ?2} in a detection bandwidth of 950 kHz. One of the orientation-patterned crystals produced 13 mW of peak power at the second-harmonic wavelength from a carbon dioxide laser with 13 W of peak power. Two crystals arranged sequentially produced 58 mW of peak power at the second-harmonic wavelength from a carbon dioxide laser with 37 W of peak power.

Bamford, D. J.; Cummings, E. A.; Panasenko, D. [Physical Sciences Inc., 6652 Owens Drive, Pleasanton, California 94588 (United States)] [Physical Sciences Inc., 6652 Owens Drive, Pleasanton, California 94588 (United States); Fenner, D. B.; Hensley, J. M. [Physical Sciences Inc., 20 New England Business Center, Andover, Massachusetts 01810 (United States)] [Physical Sciences Inc., 20 New England Business Center, Andover, Massachusetts 01810 (United States); Boivin, R. L.; Carlstrom, T. N.; Van Zeeland, M. A. [General Atomics, P.O. Box 85608, San Diego, California 92186 (United States)] [General Atomics, P.O. Box 85608, San Diego, California 92186 (United States)

2013-09-15T23:59:59.000Z

473

Electrical Bias as an Alternate Method for Reproducible Measurement of Copper Indium Gallium Diselenide (CIGS) Photovoltaic Modules: Preprint  

SciTech Connect (OSTI)

Light-to-dark metastable changes in thin-film photovoltaic (PV) modules can introduce uncertainty when measuring module performance on indoor flash testing equipment. This study describes a method to stabilize module performance through forward-bias current injection rather than light exposure. Measurements of five pairs of thin-film copper indium gallium diselenide (CIGS) PV modules indicate that forward-bias exposure maintained the PV modules at a stable condition (within 1%) while the unbiased modules degraded in performance by up to 12%. It was additionally found that modules exposed to forward bias exhibited stable performance within about 3% of their long-term outdoor exposed performance. This carrier-injection method provides a way to reduce uncertainty arising from fast transients in thin-film module performance between the time a module is removed from light exposure and when it is measured indoors, effectively simulating continuous light exposure by injecting minority carriers that behave much as photocarriers do. This investigation also provides insight into the initial light-induced transients of thin-film modules upon outdoor deployment.

Deline, C.; Stokes, A.; Silverman, T. J.; Rummel, S.; Jordan, D.; Kurtz, S.

2012-08-01T23:59:59.000Z

474

Saddle-like deformation in a dielectric elastomer actuator embedded with liquid-phase gallium-indium electrodes  

SciTech Connect (OSTI)

We introduce a dielectric elastomer actuator (DEA) composed of liquid-phase Gallium-Indium (GaIn) alloy electrodes embedded between layers of poly(dimethylsiloxane) (PDMS) and examine its mechanics using a specialized elastic shell theory. Residual stresses in the dielectric and sealing layers of PDMS cause the DEA to deform into a saddle-like geometry (Gaussian curvature K<0). Applying voltage ? to the liquid metal electrodes induces electrostatic pressure (Maxwell stress) on the dielectric and relieves some of the residual stress. This reduces the longitudinal bending curvature and corresponding angle of deflection ?. Treating the elastomer as an incompressible, isotropic, NeoHookean solid, we develop a theory based on the principle of minimum potential energy to predict the principal curvatures as a function of ?. Based on this theory, we predict a dependency of ? on ? that is in strong agreement with experimental measurements performed on a GaIn-PDMS composite. By accurately modeling electromechanical coupling in a soft-matter DEA, this theory can inform improvements in design and fabrication.

Wissman, J., E-mail: jwissman@andrew.cmu.edu [Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Finkenauer, L. [Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Deseri, L. [DICAM, Department of Mechanical, Civil and Environmental Engineering, University of Trento, via Mesiano 77 38123 Trento (Italy); TMHRI-Department of Nanomedicine, The Methodist Hospital Research Institute, 6565 Fannin St., MS B-490 Houston, Texas 77030 (United States); Mechanics, Materials and Computing Center, CEE and ME-CIT, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Majidi, C. [Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Robotics Institute and Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)

2014-10-14T23:59:59.000Z

475

Efficient Bulk Data Replication for the Earth System Grid  

SciTech Connect (OSTI)

The Earth System Grid (ESG) community faces the difficult challenge of managing the distribution of massive data sets to thousands of scientists around the world. To move data replicas efficiently, the ESG has developed a data transfer management tool called the Bulk Data Mover (BDM). We describe the performance results of the current system and plans towards extending the techniques developed so far for the up- coming project, in which the ESG will employ advanced networks to move multi-TB datasets with the ulti- mate goal of helping researchers understand climate change and its potential impacts on world ecology and society.

Sim, Alex; Gunter, Dan; Natarajan, Vijaya; Shoshani, Arie; Williams, Dean; Long, Jeff; Hick, Jason; Lee, Jason; Dart, Eli

2010-03-10T23:59:59.000Z

476

Radiative cooling of bulk silicon by incoherent light pump  

SciTech Connect (OSTI)

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, 0.47–0.94??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.

Malyutenko, V. K., E-mail: malyut@isp.kiev.ua; Bogatyrenko, V. V.; Malyutenko, O. Yu. [V. E. Lashkaryov Institute of Semiconductor Physics, 03028 Kiev (Ukraine)] [V. E. Lashkaryov Institute of Semiconductor Physics, 03028 Kiev (Ukraine)

2013-12-23T23:59:59.000Z

477

Bulk Handling of Milk on Texas Dairy Farms.  

E-Print Network [OSTI]

areas dur- tem of handling milk. ing the spring and summer of 1957 on dairy - farms which have converted their operations to Dairymen interviewed in North Texas had tanks ranging from 150 gallons to 1,000 gallons, , the bulk system of producing... and handling milk. while tanks in the Corous Christi area raneDd Texas dairy farmers are operating larger from 200 gallons to 1,000 gallons. The average units, milking more cows, selling more milk and tank in North Texas had a capacity of 400 gal. generally...

Parker, Cecil A.; Stelly, Randall, Moore, Donald S.

1958-01-01T23:59:59.000Z

478

Bulk Energy Storage Webinar Rescheduled for February 9, 2012 | Department  

Office of Environmental Management (EM)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "of Energy Power Systems EngineeringDepartment of4 Federal6Clean Energyof Energy Bulk Energy Storage

479

Bulk Hauling Equipment for CHG | Department of Energy  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-Up fromDepartmentTie Ltd:June 2015 < prevBuilding theINNOVATION &Bulk Hauling

480

Tilting the Primordial Power Spectrum with Bulk Viscosity  

E-Print Network [OSTI]

Within the context of the cold dark matter model, current observations suggest that inflationary models which generate a tilted primordial power spectrum with negligible gravitational waves provide the most promising mechanism for explaining large scale clustering. The general form of the inflationary potential which produces such a spectrum is a hyperbolic function and is interpreted physically as a bulk viscous stress contribution to the energy-momentum of a perfect baryotropic fluid. This is equivalent to expanding the equation of state as a truncated Taylor series. Particle physics models which lead to such a potential are discussed.

James E. Lidsey

1993-12-16T23:59:59.000Z

Note: This page contains sample records for the topic "bulk gallium nitride" from the National Library of EnergyBeta (NLEBeta).
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481

Very long single- and few-walled boron nitride nanotubes via the pressurized vapor/condenser method  

SciTech Connect (OSTI)

Boron nitride nanotubes (BNNTs) are desired for their exceptional mechanical, electronic, thermal, structural, textural, optical, and quantum properties. A new method for producing long, small-diameter, single- and few-walled, boron nitride nanotubes (BNNTs) in macroscopic quantities is reported. The pressurized vapor/condenser (PVC) method produces, without catalysts, highly crystalline, very long, small-diameter, BNNTs. Palm-sized, cotton-like masses of BNNT raw material were grown by this technique and spun directly into centimeters-long yarn. Nanotube lengths were observed to be 100 times that of those grown by the most closely related method. Self-assembly and growth models for these long BNNTs are discussed.

Michael W. Smith, Kevin Jordan, Cheol Park, Jae-Woo Kim, Peter Lillehei, Roy Crooks, Joycelyn Harrison

2009-11-01T23:59:59.000Z