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Sample records for indium nitride inn

  1. Influences of residual oxygen impurities, cubic indium oxide grains and indium oxy-nitride alloy grains in hexagonal InN crystalline films grown on Si(111) substrates by electron cyclotron resonance plasma-assisted molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Yodo, T.; Nakamura, T.; Kouyama, T.; Harada, Y.

    2005-05-01

    We investigated the influences of residual oxygen (O) impurities, cubic indium oxide (-In2O3) grains and indium oxy-nitride (InON) alloy grains in 200 nm-thick hexagonal ()-InN crystalline films grown on Si(111) substrates by electron cyclotron resonance plasma-assisted molecular beam epitaxy. Although -In2O3 grains with wide band-gap energy were formed in In film by N2 annealing, they were not easily formed in N2-annealed InN films. Even if they were not detected in N2-annealed InN films, the as-grown films still contained residual O impurities with concentrations of less than 0.5% ([O]0.5%). Although [O]1% could be estimated by investigating In2O3 grains formed in N2-annealed InN films, [O]0.5% could not be measured by it. However, we found that they can be qualitatively measured by investigating In2O3 grains formed by H2 annealing with higher reactivity with InN and O2, using X-ray diffraction and PL spectroscopy. In this paper, we discuss the formation mechanism of InON alloy grains in InN films.

  2. Growth of gallium nitride and indium nitride nanowires on conductive and flexible carbon cloth substrates.

    PubMed

    Yang, Yi; Ling, Yichuan; Wang, Gongming; Lu, Xihong; Tong, Yexiang; Li, Yat

    2013-03-07

    We report a general strategy for synthesis of gallium nitride (GaN) and indium nitride (InN) nanowires on conductive and flexible carbon cloth substrates. GaN and InN nanowires were prepared via a nanocluster-mediated growth method using a home built chemical vapor deposition (CVD) system with Ga and In metals as group III precursors and ammonia as a group V precursor. Electron microscopy studies reveal that the group III-nitride nanowires are single crystalline wurtzite structures. The morphology, density and growth mechanism of these nanowires are determined by the growth temperature. Importantly, a photoelectrode fabricated by contacting the GaN nanowires through a carbon cloth substrate shows pronounced photoactivity for photoelectrochemical water oxidation. The ability to synthesize group III-nitride nanowires on conductive and flexible substrates should open up new opportunities for nanoscale photonic, electronic and electrochemical devices.

  3. Chemical synthesis of hexagonal indium nitride nanocrystallines at low temperature

    NASA Astrophysics Data System (ADS)

    Wang, Liangbiao; Shen, Qianli; Zhao, Dejian; Lu, Juanjuan; Liu, Weiqiao; Zhang, Junhao; Bao, Keyan; Zhou, Quanfa

    2017-08-01

    In this study, hexagonal indium nitride nanocystallines with high crystallinity have been prepared by the reaction of InCl3·4H2O, sulfur and NaNH2 in an autoclave at 160 °C. The crystal structures and morphologies of the obtained InN sample are characterized by X-ray diffraction and scanning electron microscope. As InCl3·4H2O is substituted by In(NO3)3·4.5H2O, InN nanocrystallines could also be obtained by using the similar method. The photoluminescence spectrum shows that the InN emits a broad peak positioned at 2.3 eV.

  4. High-pressure CVD Growth of InN and Indium-rich Group III-nitride Compound Semiconductors for Novel Mid- and Far-infrared Detectors and Emitters

    DTIC Science & Technology

    2010-02-01

    polarity of Group III-nitride crystals. A higher concentration of indium in InGaN/GaN quantum wells (QW) results in more strain and more polarization36...fluctuation) induced localized states in the InGaN layers play major roles in achieving highly efficient blue and green InGaN multiple quantum wells (MQW...the phase segregation process in dissimilar materials, or  the formation of straight or compositional graded quantum wells . p. 15 Figure 10

  5. Selective-area growth of indium nitride nanowires on gold-patterned Si(100) substrates

    NASA Astrophysics Data System (ADS)

    Liang, C. H.; Chen, L. C.; Hwang, J. S.; Chen, K. H.; Hung, Y. T.; Chen, Y. F.

    2002-07-01

    This letter reports the synthesis of indium nitride (InN) nanowires on gold-patterned silicon substrates in a controlled manner using a method involving thermal evaporation of pure indium. The locations of these InN nanowires were controlled by depositing gold in desired areas on the substrates. Scanning electron microscopy and transmission electron microscopy investigations showed that the InN nanowires are single crystals with diameters ranging from 40 to 80 nm, and lengths up to 5 mum. Energy dispersive x-ray spectrometry showed that the ends of the nanowires are composed primarily of Au, and the rest of the nanowires were InN with no detectable Au incorporations. The Raman spectra showed peaks at 445, 489, and 579 cm-1, which are attributed to the A1(transverse optical), E2, and A1(longitudinal optical) phonon modes of the wurtzite InN structure, respectively. Photoluminescence spectra of the InN nanowires showed a strong broad emission peak at 1.85 eV.

  6. Strategies to indium nitride and gallium nitride nanoparticles: Low-temperature, solution-phase and precursor routes

    NASA Astrophysics Data System (ADS)

    Dingman, Sean Douglas

    I present new strategies to low-temperature solution-phase synthesis of indium and gallium nitride (InN and GaN) ceramic materials. The strategies include: direct conversion of precursor molecules to InN by pyrolysis, solution-phase synthesis of nanostructured InN fibers via molecular precursors and co-reactants, and synthesis of powders through reactions derived from molten-salt chemistry. Indium nitride powders are prepared by pyrolysis of the precursors R 2InN3 (R = t-Bu (1), i-Amyl(2), Et(3), i-Pr( 4)). The precursors are synthesized via azide-alkoxide exchange of R2InOMe with Me3SiN3. The precursors are coordination polymers containing five-coordinate indium centers. Pyrolysis of 1 and 2 under N2 at 400°C yields powders consisting primarily of InN with average crystal sizes of 15--35 nm. 1 yields nanocrystalline InN with average particle sizes of 7 nm at 250°C. 3 and 4 yield primarily In metal from pyrolysis. Refluxing 1 in diisopropylbenzene (203°C) in the presence of primary amines yields InN nanofibers 10--100 nm in length. InN nanofibers of up to 1 mum can be synthesized by treating 1 with 1,1-dimethylhydrazine (DMHy) The DMHy appears to control the fiber length by acting as a secondary source of active nitrogen in order to sustain fiber growth. The resulting fibers are attached to droplets of indium metal implying a solution-liquid-solid growth mechanism. Precursor 4 yields crystalline InN whiskers when reacted with DMHy. Reactions of 4 with reducing agents such as HSnBu3, yield InN nanoparticles with an average crystallite size of 16 nm. Gallium precursors R2GaN3 (R = t-Bu( 5), Me3SiCH2(6) and i-Pr( 7)), synthesized by azide-alkoxide exchange, are found to be inert toward solution decomposition and do not yield GaN. These compounds are molecular dimers and trimers unlike the indium analogs. Compound 6 displays a monomer-dimer equilibrium in benzene solution, but exists as a solid-state trimer. InN powders are also synthesized by reactions of InCl3 and

  7. Growth and morphology of 0.80 eV photoemitting indium nitride nanowires

    SciTech Connect

    Johnson, M.C.; Lee, C.J.; Bourret-Courchesne, E.D.; Konsek, S.L.; Aloni, S.; Han, W.Q.; Zettl, A.

    2004-08-13

    InN nanowires with high efficiency photoluminescence emission at 0.80 eV are reported for the first time. InN nanowires were synthesized via a vapor solid growth mechanism from high purity indium metal and ammonia. The products consist of only hexagonal wurtzite phase InN. Scanning electron microscopy showed wires with diameters of 50-100nm and having fairly smooth morphologies. High-resolution transmission electron microscopy revealed high quality, single crystal InN nanowires which grew in the <0001> direction. The group-III nitrides have become an extremely important technological material over the past decade. They are commonly used in optoelectronic devices, such as high brightness light-emitting diodes (LEDs) and low wavelength laser diodes (LDs), as well as high power/high frequency electronic devices. Recently InN thin films grown by MOCVD and MBE were found to have a bandgap energy in the range of 0.7-0.9 eV, much lower than the value of {approx}1.9 eV found for InN films grown by sputtering. This large decrease in the direct bandgap transition energy and the ability to form ternary (InGaN) and quaternary (AlInGaN) alloys increases the versatility of group-III nitride optoelectronic devices, ranging from the near IR to the UV. Additionally, InN has some promising transport and electronic properties. It has the smallest effective electron mass of all the group-III nitrides which leads to high mobility and high saturation velocity10 and a large drift velocity at room temperature. As a result of these unique properties, there has been a large increase in interest in InN for potential use in optoelectronic devices, such as LDs and high efficiency solar cells, as well as high frequency/high power electronic devices.

  8. Compositional analysis of dilute nitride doped indium antimonide bulk crystal by VDS technique

    SciTech Connect

    Deshpande, Manisha; Maske, Dilip; Choudhari, Rashmi; Gadkari, Dattatray; Arora, Brij Mohan

    2016-05-06

    Dilute nitrides are suitable materials for fabrication of devices in detection of long wavelength infrared region. Dilute nitride doped Indium antimonide bulk crystals were grown using vertical directional solidification technique. The compositional characteristics of the crystals were carried out using EDS. The analysis was simulated and compared with observations using DTSA II software for accuracy. The ingots have uniform composition of Indium and Antimony. The actual nitrogen composition measured using EDS was 0.136% for doped nitrogen composition 0.1% except near conical end where it was 0.1%. The study of bonding between nitrogen, Indium and antimony was carried out using SIMS. The analysis shows strong presence of In-N bonding along with In-Sb bonds which indicates nitrogen has replaced antimony atoms in crystal lattice.

  9. Elastic properties of indium nitrides grown on sapphire substrates determined by nano-indentation: In comparison with other nitrides

    NASA Astrophysics Data System (ADS)

    Yonenaga, Ichiro; Ohkubo, Yasushi; Deura, Momoko; Kutsukake, Kentaro; Tokumoto, Yuki; Ohno, Yutaka; Yoshikawa, Akihiko; Wang, Xin Qiang

    2015-07-01

    The hardness of wurtzite indium nitride (α-InN) films of 0.5 to 4 μm in thickness was measured by the nano-indentation method at room temperature. After investigation of crystalline quality by x-ray diffraction, the hardness and Young's modulus were determined to be 8.8 ± 0.4 and 184 ± 5 GPa, respectively, for the In (0001)- and N ( 000 1 ¯ ) -growth faces of InN films. The bulk and shear moduli were then derived to be 99 ± 3 and 77 ± 2 GPa, respectively. The Poisson's ratio was evaluated to be 0.17 ± 0.03. The results were examined comprehensively in comparison with previously reported data of InN as well as those of other nitrides of aluminum nitride and gallium nitride. The underlying physical process determining the moduli and hardness was examined in terms of atomic bonding and dislocation energy of the nitrides and wurtzite zinc oxide.

  10. Molecular beam epitaxy of InN dots on nitrided sapphire

    SciTech Connect

    Romanyuk, Yaroslav E.; Dengel, Radu-Gabriel; Stebounova, LarissaV.; Leone, Stephen R.

    2007-04-20

    A series of self-assembled InN dots are grown by radio frequency (RF) plasma-assisted molecular beam epitaxy (MBE) directly on nitrided sapphire. Initial nitridation of the sapphire substrates at 900 C results in the formation of a rough AlN surface layer, which acts as a very thin buffer layer and facilitates the nucleation of the InN dots according to the Stranski-Krastanow growth mode, with a wetting layer of {approx}0.9 nm. Atomic force microscopy (AFM) reveals that well-confined InN nanoislands with the greatest height/width at half-height ratio of 0.64 can be grown at 460 C. Lower substrate temperatures result in a reduced aspect ratio due to a lower diffusion rate of the In adatoms, whereas the thermal decomposition of InN truncates the growth at T>500 C. The densities of separated dots vary between 1.0 x 10{sup 10} cm{sup -2} and 2.5 x 10{sup 10} cm{sup -2} depending on the growth time. Optical response of the InN dots under laser excitation is studied with apertureless near-field scanning optical microscopy and photoluminescence spectroscopy, although no photoluminescence is observed from these samples. In view of the desirable implementation of InN nanostructures into photonic devices, the results indicate that nitrided sapphire is a suitable substrate for growing self-assembled InN nanodots.

  11. Gallium Nitride, Indium Nitride, and Heterostructure Development Using The MEAglow Growth System

    NASA Astrophysics Data System (ADS)

    Binsted, Peter W.

    This thesis presents an in depth study of semiconductor development using a new process termed Migration Enhanced Afterglow (MEAglow). The MEAglow growth reactor is housed in the Lakehead University Semiconductor Research Lab. Thin films of gallium nitride and indium nitride are produced as well as heterostructures comprised of these two films and their ternary alloy InGaN. MEAglow is a form of plasma enhanced chemical vapour deposition (PECVD) employing migration enhanced epitaxy (MEE). The heterostructure is being developed for a novel field effect transistor (FET) based on the tunnelling of charge carriers which alter the channel conductivity. The configuration of this unique III-Nitride device should allow the FET to function as normally off in either n-type or p-type operation. Due to the difficulties in growing low temperature GaN, test devices of this abstract design were not previously possible. Further details on the device operation and growth parameters are included. Samples produced by the research reactor were characterised through x-ray diffraction (XRD), ultraviolet-near infrared-visible spectroscopy (UV-Vis-NIR), Auger spectroscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). Film growth is accomplished by an improved form of pulsed delivery Plasma Enhanced Chemical Vapour Deposition (PECVD). The reactor features a scalable hollow cathode type plasma source. Data obtained through characterisation is subjected to theoretical treatment which explains much not previously understood behaviour of the GaN films. Many challenges in III-Nitride film growth have been overcome during this research project. A method of developing structures consisting of InN and GaN within the same system has been proven.

  12. Indium Nitride: A New Material for High Efficiency, Compact, 1550NM Laser-Based Terahertz Sources in Explosives Detection and Concealed Weapons Imaging

    DTIC Science & Technology

    2006-11-01

    INDIUM NITRIDE: A NEW MATERIAL FOR HIGH EFFICIENCY, COMPACT, 1550NM LASER-BASED TERAHERTZ SOURCES IN EXPLOSIVES DETECTION AND CONCEALED WEAPONS...nitride (InN) is identified as a promising terahertz (THz) emitter based on the optical and electronic properties of high quality In- and N-face...significant improvements in THz emitters. 1. INTRODUCTION The terahertz region of the electromagnetic spectrum, lying between microwave frequencies

  13. Role of nitridation on polarity and growth of InN by metal-organic vapor phase epitaxy

    NASA Astrophysics Data System (ADS)

    Dinh, Duc V.; Skuridina, D.; Solopow, S.; Pristovsek, M.; Vogt, P.; Kneissl, M.

    2013-08-01

    We report on metal-organic vapor phase epitaxy (MOVPE) of (0001)InN layers simultaneously grown on a-plane (112¯0) and c-plane (0001) sapphire substrates. The substrates were nitridated at temperatures from 500 °C to 1050 °C prior to the growth of c-plane InN layers. Nitridation determined the polarity, the crystallinity, and the surface morphology of the InN layers. Nitridation temperatures above 800 °C lead to N-polar InN layers, while nitridation temperatures from 700 °C to 750 °C produce mixed-polar InN layers, and nitridation temperatures from 500 °C to 650 °C produce In-polar InN layers. The roughness and crystallinity of the InN layers are correlated with the changes of polarity. The incorporation of nitrogen into the nitridation layers at different nitridation temperatures was measured. A strong N-Al bond signal after nitridation is correlated with N-polarity layers after overgrowth.

  14. Indium Gallium Nitride Multijunction Solar Cell Simulation Using Silvaco Atlas

    DTIC Science & Technology

    2007-06-01

    in production from the mid-1960s until the early 1990s. Their efficiency was close to 15%. The next step consisted of single junction gallium ...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS Approved for public release; distribution is unlimited INDIUM GALLIUM ...TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE Indium Gallium Nitride Multijunction Solar Cell Simulation Using Silvaco Atlas 6

  15. Growth and characterization of indium nitride layers grown by high-pressure chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Alevli, Mustafa

    V for samples of lower electron concentration. The Raman analysis revealed a high-quality crystalline layer with a FWHM for the E2(high) peak around 6.9 cm-1. The results presented in our study suggest that the optimum molar ratio might be below 800, which is due to the efficient cracking of the ammonia precursor at the high reactor pressure and high growth temperature. Index words. Indium Nitride, In-rich group III Nitrides, III-V semiconductors, High-Pressure, Chemical Vapor Deposition, V/III molar ratio.

  16. High-phase-purity zinc-blende InN on r-plane sapphire substrate with controlled nitridation pretreatment

    NASA Astrophysics Data System (ADS)

    Hsiao, Ching-Lien; Liu, Ting-Wei; Wu, Chien-Ting; Hsu, Hsu-Cheng; Hsu, Geng-Ming; Chen, Li-Chyong; Shiao, Wen-Yu; Yang, C. C.; Gällström, Andreas; Holtz, Per-Olof; Chen, Chia-Chun; Chen, Kuei-Hsien

    2008-03-01

    High-phase-purity zinc-blende (zb) InN thin film has been grown by plasma-assisted molecular-beam epitaxy on r-plane sapphire substrate pretreated with nitridation. X-ray diffraction analysis shows that the phase of the InN films changes from wurtzite (w) InN to a mixture of w-InN and zb-InN, to zb-InN with increasing nitridation time. High-resolution transmission electron microscopy reveals an ultrathin crystallized interlayer produced by substrate nitridation, which plays an important role in controlling the InN phase. Photoluminescence emission of zb-InN measured at 20K shows a peak at a very low energy, 0.636eV, and an absorption edge at ˜0.62eV is observed at 2K, which is the lowest bandgap reported to date among the III-nitride semiconductors.

  17. Development of a Computational Chemical Vapor Deposition Model: Applications to Indium Nitride and Dicyanovinylaniline

    NASA Technical Reports Server (NTRS)

    Cardelino, Carlos

    1999-01-01

    A computational chemical vapor deposition (CVD) model is presented, that couples chemical reaction mechanisms with fluid dynamic simulations for vapor deposition experiments. The chemical properties of the systems under investigation are evaluated using quantum, molecular and statistical mechanics models. The fluid dynamic computations are performed using the CFD-ACE program, which can simulate multispecies transport, heat and mass transfer, gas phase chemistry, chemistry of adsorbed species, pulsed reactant flow and variable gravity conditions. Two experimental setups are being studied, in order to fabricate films of: (a) indium nitride (InN) from the gas or surface phase reaction of trimethylindium and ammonia; and (b) 4-(1,1)dicyanovinyl-dimethylaminoaniline (DCVA) by vapor deposition. Modeling of these setups requires knowledge of three groups of properties: thermodynamic properties (heat capacity), transport properties (diffusion, viscosity, and thermal conductivity), and kinetic properties (rate constants for all possible elementary chemical reactions). These properties are evaluated using computational methods whenever experimental data is not available for the species or for the elementary reactions. The chemical vapor deposition model is applied to InN and DCVA. Several possible InN mechanisms are proposed and analyzed. The CVD model simulations of InN show that the deposition rate of InN is more efficient when pulsing chemistry is used under conditions of high pressure and microgravity. An analysis of the chemical properties of DCVA show that DCVA dimers may form under certain conditions of physical vapor transport. CVD simulations of the DCVA system suggest that deposition of the DCVA dimer may play a small role in the film and crystal growth processes.

  18. Development of a Computational Chemical Vapor Deposition Model: Applications to Indium Nitride and Dicyanovinylaniline

    NASA Technical Reports Server (NTRS)

    Cardelino, Carlos

    1999-01-01

    A computational chemical vapor deposition (CVD) model is presented, that couples chemical reaction mechanisms with fluid dynamic simulations for vapor deposition experiments. The chemical properties of the systems under investigation are evaluated using quantum, molecular and statistical mechanics models. The fluid dynamic computations are performed using the CFD-ACE program, which can simulate multispecies transport, heat and mass transfer, gas phase chemistry, chemistry of adsorbed species, pulsed reactant flow and variable gravity conditions. Two experimental setups are being studied, in order to fabricate films of: (a) indium nitride (InN) from the gas or surface phase reaction of trimethylindium and ammonia; and (b) 4-(1,1)dicyanovinyl-dimethylaminoaniline (DCVA) by vapor deposition. Modeling of these setups requires knowledge of three groups of properties: thermodynamic properties (heat capacity), transport properties (diffusion, viscosity, and thermal conductivity), and kinetic properties (rate constants for all possible elementary chemical reactions). These properties are evaluated using computational methods whenever experimental data is not available for the species or for the elementary reactions. The chemical vapor deposition model is applied to InN and DCVA. Several possible InN mechanisms are proposed and analyzed. The CVD model simulations of InN show that the deposition rate of InN is more efficient when pulsing chemistry is used under conditions of high pressure and microgravity. An analysis of the chemical properties of DCVA show that DCVA dimers may form under certain conditions of physical vapor transport. CVD simulations of the DCVA system suggest that deposition of the DCVA dimer may play a small role in the film and crystal growth processes.

  19. Optical properties of InN with stoichoimetry violation and indium clustering

    NASA Astrophysics Data System (ADS)

    Shubina, T. V.; Ivanov, S. V.; Jmerik, V. N.; Glazov, M. M.; Kalvarskii, A. P.; Tkachman, M. G.; Vasson, A.; Leymarie, J.; Kavokin, A.; Amano, H.; Akasaki, I.; Butcher, K. S. A.; Guo, Q.; Monemar, B.; Kop'ev, P. S.

    2005-02-01

    We demonstrate that nonstoichiometry is one of the main reason of strong deviation of the InN optical gap in the 0.7-2 eV range, with N/In < 1 and N/In > 1 corresponding to the lower and higher energies, respectively. The phenomenon is discussed in terms of atomic orbital energies, which are strongly different for indium and nitrogen, therefore both excess atom incorporation and elimination could change the optical gap. We estimate such trends using the approximation of the empirical nearest-neighbor tight binding theory. It is also demonstrated that resonant absorption in In-enriched regions is an additional factor lowering an effective absorption edge.

  20. Development of an Advanced Computational Model for OMCVD of Indium Nitride

    NASA Technical Reports Server (NTRS)

    Cardelino, Carlos A.; Moore, Craig E.; Cardelino, Beatriz H.; Zhou, Ning; Lowry, Sam; Krishnan, Anantha; Frazier, Donald O.; Bachmann, Klaus J.

    1999-01-01

    An advanced computational model is being developed to predict the formation of indium nitride (InN) film from the reaction of trimethylindium (In(CH3)3) with ammonia (NH3). The components are introduced into the reactor in the gas phase within a background of molecular nitrogen (N2). Organometallic chemical vapor deposition occurs on a heated sapphire surface. The model simulates heat and mass transport with gas and surface chemistry under steady state and pulsed conditions. The development and validation of an accurate model for the interactions between the diffusion of gas phase species and surface kinetics is essential to enable the regulation of the process in order to produce a low defect material. The validation of the model will be performed in concert with a NASA-North Carolina State University project.

  1. Development of an Advanced Computational Model for OMCVD of Indium Nitride

    NASA Technical Reports Server (NTRS)

    Cardelino, Carlos A.; Moore, Craig E.; Cardelino, Beatriz H.; Zhou, Ning; Lowry, Sam; Krishnan, Anantha; Frazier, Donald O.; Bachmann, Klaus J.

    1999-01-01

    An advanced computational model is being developed to predict the formation of indium nitride (InN) film from the reaction of trimethylindium (In(CH3)3) with ammonia (NH3). The components are introduced into the reactor in the gas phase within a background of molecular nitrogen (N2). Organometallic chemical vapor deposition occurs on a heated sapphire surface. The model simulates heat and mass transport with gas and surface chemistry under steady state and pulsed conditions. The development and validation of an accurate model for the interactions between the diffusion of gas phase species and surface kinetics is essential to enable the regulation of the process in order to produce a low defect material. The validation of the model will be performed in concert with a NASA-North Carolina State University project.

  2. Effect of polarization field on mean free path of phonons in indium nitride

    SciTech Connect

    Sahoo, Sushant Kumar

    2016-05-06

    The effect of built-in-polarization field on mean free path of acoustic phonons in bulk wurtzite indium nitride (InN) has been theoretically investigated. The elastic constant of the material gets modified due to the existence of polarization field. As a result velocity and Debye frequency of phonons get enhanced. The various scattering rates of phonons are suppressed by the effect of polarization field, which implies an enhanced combined relaxation time. Thus phonons travel freely for a longer distance between two successive scatterings. This would enhance the thermal transport properties of the material when built-in-polarization field taken into account. Hence by the application of electric field the transport properties of such materials can be controlled as and when desired.

  3. Indium Gallium Nitride/Gallium Nitride (InGaN/GaN) Nanorods Superlattice (SL)

    DTIC Science & Technology

    2006-03-10

    barrier escape from localized states and/or to the capture at non-radiative centers inside the InGaN wells. Therefore, extraction efficiency and internal...1 Final Report Principal investigator : Prof. Tae Won Kang Title of proposal : Indium Gallium Nitride/Gallium Nitride ( InGaN /GaN) Nanorods...radiation. One-dimensional nanostructures, such as InGaN /GaN nanorod supperlattice (NRs SL), have attracted much attention because of its potential

  4. Formation of polar InN with surface Fermi level near the valence band maximum by means of ammonia nitridation

    NASA Astrophysics Data System (ADS)

    Dahl, J.; Kuzmin, M.; Adell, J.; Balasubramanian, T.; Laukkanen, P.

    2012-12-01

    Development of InN films for devices is hindered due to metallic In clusters, formed readily during growth, and unintentional n-type conductivity of the nominally undoped films, including surface electron-accumulation layers via the Fermi level pinning into the conduction band. Plasma nitridation eliminates even large In clusters from the surface by changing them to two-dimensional InN [Yamaguchi and Nanishi, Appl. Phys. Expr.10.1143/APEX.2.051001 2, 051001 (2009)]. Here we utilized a similar approach, that is, nitridation of In-covered surfaces with ammonia (NH3) to grow thin, up to 25 nm thick polar InN films on Si(111) and GaN(0001) substrates. By means of scanning tunneling microscopy and spectroscopy, as well as photoelectron spectroscopy, we show that this simple NH3 nitridation provides the hitherto not reported formation of polar InN(000-1) films with the surface Fermi level close to the valence band maximum, as recent calculations [Belabbes , Phys. Rev. B10.1103/PhysRevB.84.205304 84, 205304 (2011)] predict.

  5. Superconductivity of Ca2 InN with a layered structure embedding an anionic indium chain array

    NASA Astrophysics Data System (ADS)

    Jeong, Sehoon; Matsuishi, Satoru; Lee, Kimoon; Toda, Yoshitake; Wng Kim, Sung; Hosono, Hideo

    2014-05-01

    We report the emergence of superconductivity in Ca2InN consisting of a two-dimensional (2D) array of zigzag indium chains embedded between Ca2N layers. A sudden drop of resistivity and a specific heat (Cp) jump attributed to the superconducting transition were observed at 0.6 K. The Sommerfeld coefficient γ = 4.24 mJ mol-1K-2 and Debye temperature ΘD = 322 K were determined from the Cp of the normal conducting state and the superconducting volume fraction was estimated to be ˜80% from the Cp jump, assuming a BCS-type weak coupling. Density functional theory calculations demonstrated that the electronic bands near the Fermi level (EF) are mainly derived from In 5p orbitals with π and σ bonding states and the Fermi surface is composed of cylindrical parts, corresponding to the quasi-2D electronic state of the In-chain array. By integrating the projected density of states of the In-p component up to EF, a valence electron population of ˜1.6 electrons/In was calculated, indicating that partially anionic state of In. The In 3d binding energies observed in Ca2InN by x-ray photoemission spectroscopy were negatively shifted from that in In metal. The superconductivity of Ca2InN is associated with the p-p bonding states of the anionic In layer.

  6. Investigation of optical band gap and optical phonons in indium nitride and indium aluminum nitride films

    NASA Astrophysics Data System (ADS)

    Haddad, Daad Bourhan

    2003-07-01

    We have studied the optical band gap in InN thin films and the optical phonon modes in the ternary alloy thin films, In1-x AlxN (0 ≤ x ≤ 1). The In1-xAl xN films with 0 ≤ x ≤ 1 were grown by Plasma Source Molecular Beam Epitaxy (PSMBE) on sapphire (0001) substrates. The optical properties of InN thin films (˜0.5 mum thick) grown at different substrate temperatures have been measured in order to study the effect of electron degeneracy on the band gap measurement. Hall measurements indicate that the films are n-type with a high carrier concentration (>1020 cm -3). The optical absorption data on these samples show ne dependent band gap edge and a peak corresponding to plasmon due to strong electron degeneracy. By incorporating the influence of electron degeneracy on the optical absorption data, the calculated value of true band gap energy for these films is found to be ˜0.7 eV. This value is much smaller than the earlier reported values (˜1.9 eV) in the literature, but in better agreement with recent band gap measurements on high quality InN films. In addition, the analysis of the optical absorption data of a high quality non-degenerate InN film with ne ˜7 x 1017 cm-3, obtained from Cornell University, results in an observed optical band gap energy ˜0.6 eV. The role of plasmon and LO-phonon damping on the optical measurements of InN films is discussed. The phonon and plasmon damping dramatically modify the spectral features of the optical spectra and destabilize coupled-modes of the system. The phonon damping affects the optical properties in a qualitatively different way than plasmon damping. The low-energy optical transmission region formed in between the coupled-modes in weakly damped situations is investigated. The effect of plasmon and LO-phonon coupling on the analyses of the experimental infrared reflection data of InN films (with different electron densities) is discussed. UV and visible near-resonance enhanced Raman scattering measurements in

  7. The steady-state and transient electron transport within bulk zinc-blende indium nitride: The impact of crystal temperature and doping concentration variations

    SciTech Connect

    Siddiqua, Poppy; O'Leary, Stephen K.

    2016-03-07

    Within the framework of a semi-classical three-valley Monte Carlo electron transport simulation approach, we analyze the steady-state and transient aspects of the electron transport within bulk zinc-blende indium nitride, with a focus on the response to variations in the crystal temperature and the doping concentration. We find that while the electron transport associated with zinc-blende InN is highly sensitive to the crystal temperature, it is not very sensitive to the doping concentration selection. The device consequences of these results are then explored.

  8. Low-threshold indium gallium nitride quantum dot microcavity lasers

    NASA Astrophysics Data System (ADS)

    Woolf, Alexander J.

    Gallium nitride (GaN) microcavities with embedded optical emitters have long been sought after as visible light sources as well as platforms for cavity quantum electrodynamics (cavity QED) experiments. Specifically, materials containing indium gallium nitride (InGaN) quantum dots (QDs) offer an outstanding platform to study light matter interactions and realize practical devices, such as on-chip light emitting diodes and nanolasers. Inherent advantages of nitride-based microcavities include low surface recombination velocities, enhanced room-temperature performance (due to their high exciton binding energy, as high as 67 meV for InGaN QDs), and emission wavelengths in the blue region of the visible spectrum. In spite of these advantages, several challenges must be overcome in order to capitalize on the potential of this material system. Such diffculties include the processing of GaN into high-quality devices due to the chemical inertness of the material, low material quality as a result of strain-induced defects, reduced carrier recombination effciencies due to internal fields, and a lack of characterization of the InGaN QDs themselves due to the diffculty of their growth and therefore lack of development relative to other semiconductor QDs. In this thesis we seek to understand and address such issues by investigating the interaction of light coupled to InGaN QDs via a GaN microcavity resonator. Such coupling led us to the demonstration of the first InGaN QD microcavity laser, whose performance offers insights into the properties and current limitations of the nitride materials and their emitters. This work is organized into three main sections. Part I outlines the key advantages and challenges regarding indium gallium nitride (InGaN) emitters embedded within gallium nitride (GaN) optical microcavities. Previous work is also discussed which establishes context for the work presented here. Part II includes the fundamentals related to laser operation, including the

  9. Exploiting the Negative Polarization Properties of Indium Gallium Nitride (InGaN)/Gallium Nitride (GaN) Heterostructures to Achieve Frequency Doubled Blue-green Lasers with Deep UV (250 nm) Emission (Year 2)

    DTIC Science & Technology

    2011-05-01

    Exploiting the Negative Polarization Properties of Indium Gallium Nitride ( InGaN )/Gallium Nitride (GaN) Heterostructures to Achieve Frequency...Polarization Properties of Indium Gallium Nitride ( InGaN )/Gallium Nitride (GaN) Heterostructures to Achieve Frequency Doubled Blue-green Lasers...Exploiting the Negative Polarization Properties of Indium Gallium Nitride ( InGaN )/Gallium Nitride (GaN) Heterostructures to Achieve Frequency Doubled

  10. Exploiting the Negative Polarization Properties of Indium Gallium Nitride (InGaN)/Gallium Nitride (GaN) Heterostructures to Achieve Frequency Doubled Blue-green Lasers with Deep Ultraviolet (UV) (

    DTIC Science & Technology

    2010-06-01

    Exploiting the Negative Polarization Properties of Indium Gallium Nitride ( InGaN )/Gallium Nitride (GaN) Heterostructures to Achieve Frequency...Exploiting the Negative Polarization Properties of Indium Gallium Nitride ( InGaN )/Gallium Nitride (GaN) Heterostructures to Achieve...TITLE AND SUBTITLE Exploiting the Negative Polarization Properties of Indium Gallium Nitride ( InGaN )/Gallium Nitride (GaN) Heterostructures to Achieve

  11. Development of wide-band gap indium gallium nitride solar cells for high-efficiency photovoltaics

    NASA Astrophysics Data System (ADS)

    Jani, Omkar K.

    Main objective of the present work is to develop wide-band gap InGaN solar cells in the 2.4--2.9 eV range that can be an integral component of photovoltaic devices to achieve efficiencies greater than 50%. The III-nitride semiconductor material system, which consists of InN, GaN, AlN and their alloys, offers a substantial potential in developing ultra-high efficiency photovoltaics mainly due to its wide range of direct-band gap, and other electronic, optical and mechanical properties. However, this novel InGaN material system poses challenges from theoretical, as well as technological standpoints, which are further extended into the performance of InGaN devices. In the present work, these challenges are identified and overcome individually to build basic design blocks, and later, optimized comprehensively to develop high-performance InGaN solar cells. One of the major challenges from the theoretical aspect arises due to unavailability of a suitable modeling program for InGaN solar cells. As spontaneous and piezoelectric polarization can substantially influence transport of carriers in the III-nitrides, these phenomena are studied and incorporated at a source-code level in the PC1D simulation program to accurately model InGaN solar cells. On the technological front, InGaN with indium compositions up to 30% (2.5 eV band gap) are developed for photovoltaic applications by controlling defects and phase separation using metal-organic chemical vapor deposition. InGaN with band gap of 2.5 eV is also successfully doped to achieve acceptor carrier concentration of 1018 cm-3. A robust fabrication scheme for III-nitride solar cells is established to increase reliability and yield; various schemes including interdigitated grid contact and current spreading contacts are developed to yield low-resistance Ohmic contacts for InGaN solar cells. Preliminary solar cells are developed using a standard design to optimize the InGaN material, where the band gap of InGaN is progressively

  12. Investigation of indium gallium nitride facet-dependent nonpolar growth rates and composition for core-shell light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Gîrgel, Ionut; Edwards, Paul R.; Le Boulbar, Emmanuel; Coulon, Pierre-Marie; Sahonta, Suman-Lata; Allsopp, Duncan W. E.; Martin, Robert W.; Humphreys, Colin J.; Shields, Philip A.

    2016-01-01

    Core-shell indium gallium nitride (InGaN)/gallium nitride (GaN) structures are attractive as light emitters due to the large nonpolar surface of rod-like cores with their longitudinal axis aligned along the c-direction. These facets do not suffer from the quantum-confined Stark effect that limits the thickness of quantum wells and efficiency in conventional light-emitting devices. Understanding InGaN growth on these submicron three-dimensional structures is important to optimize optoelectronic device performance. In this work, the influence of reactor parameters was determined and compared. GaN nanorods (NRs) with both {11-20} a-plane and {10-10} m-plane nonpolar facets were prepared to investigate the impact of metalorganic vapor phase epitaxy reactor parameters on the characteristics of a thick (38 to 85 nm) overgrown InGaN shell. The morphology and optical emission properties of the InGaN layers were investigated by scanning electron microscopy, transmission electron microscopy, and cathodoluminescence hyperspectral imaging. The study reveals that reactor pressure has an important impact on the InN mole fraction on the {10-10} m-plane facets, even at a reduced growth rate. The sample grown at 750°C and 100 mbar had an InN mole fraction of 25% on the {10-10} facets of the NRs.

  13. Evaluation of the indium gallium nitride/silicon broken-gap heterojunction and its potential application for solar cells

    NASA Astrophysics Data System (ADS)

    Yao, Yuan

    InGaN (especially In-rich alloy) has been actively studied for decades since the band gap of InN was revised downward from ˜2.0 eV to 0.64 eV. The potential applications for alloys of In-rich InGaN hence became apparent. Despite the promising potential, photovoltaic devices based on InGaN have struggled due to a number of key limitations and fundamental physical problems. Firstly, due to the deep excursion of the InN conduction band at the gamma point, defects in InN are almost universally n-type leading to unintentional degenerate doping. This also leads to the problem of electron accumulation at all surfaces and interfaces of InN. Secondly, p-type doping is problematic, partially due to the degenerate doping effect of defects, but it has also been observed that Mg-doping, while leading to a p-type layer, dramatically reduces the quantum efficiency. This thesis explores an alternative approach using n-type InGaN to form a heterojunction with a p-type Si substrate. One potential benefit to using p-type Si as a substrate material for InGaN is that the valence band of Si possibly lines up with the conduction band of InGaN for a specific mole fraction of indium. Such a band alignment is known as a broken gap heterojunction, an example of which is the interface between InAs and AlxGa 1--xSb. The benefits of this broken-gap junction include a low series resistance, high electron mobility, and mobility only weakly dependent on temperature. These properties enable new approach to photovoltaic devices. The InGaN/Si heterojunctions were fabricated by plasma-assisted molecular beam epitaxy under stoichiometric flux conditions. An ultra-thin SiN interface layer was introduced, by Si nitridation process, to passivate the substrate surface and prevent In-Si and Ga-Si eutectic problems. InGaN films with a variety of indium mole fractions were grown by calibrating the In/Ga flux ratio during the deposition. The chemical composition of as-grown films was characterized by x

  14. The optimum heavy ion beam for the compositional analysis of indium nitride films

    NASA Astrophysics Data System (ADS)

    Shrestha, Santosh K.; Timmers, Heiko

    2006-08-01

    Ideal growth conditions for the III-V semiconductor indium nitride have not been identified. Indium nitride films have been shown to have excess nitrogen and often contain oxygen and carbon. Elastic recoil detection analysis of indium nitride using a 200 MeV 197Au beam is affected by considerable nitrogen depletion. The composition can, however, accurately be determined with a large solid angle gas ionization detector and through application of the bulk molecular recombination model. To avoid nitrogen depletion, in this work projectiles with atomic numbers lower than that of 197Au have been investigated. Whereas a 19F beam cannot effectively be employed, with a 32S beam the precise compositional analysis of indium nitride is possible. In this case nitrogen depletion is insignificant and accuracy is only limited by counting statistics. The use of a 32S beam is also superior to the use of a 109Ag beam. For the latter nitrogen depletion does occur, albeit somewhat reduced when compared with 197Au. A threshold atomic number may exist below which the depletion of nitrogen is absent.

  15. Plasma-assisted molecular beam epitaxy growth and properties of indium-face indium nitride

    NASA Astrophysics Data System (ADS)

    Gallinat, Chad Stephen

    In this work, the PAMBE growth of high-quality InN films was developed. Using the in situ growth analysis tools, RHEED and line-of-site quadrupole mass spectrometry (QMS), the thermal decomposition of both Inand N-face InN was explored to determine attainable growth temperatures and growth rate limitations. Surface structure growth diagrams were constructed for both In- and N-face InN. In-face InN was shown to have only two growth regimes below 500ºC--the In-droplet regime and the N-rich regime. Attempts to grow beyond 500ºC resulted in In-droplet accumulation with no InN growth. Both In- and N-face InN exhibited the smoothest surface morphologies and lowest dislocation densities for films grown with excess In. The dependence of electrical transport properties on growth conditions were studied for In-face InN. An accumulation of electrons with a density of 5.1 x 1013 cm-2 was measured at the sample surface due to occupied surface states above the bulk conduction band minimum. This surface accumulation layer interfered with direct Hall measurements of bulk carriers, but a two-layer Hall model was used to extract bulk electron concentrations and mobilities. Even when accounting for this surface accumulation layer, all of the InN films exhibited a degenerate level of unintentionally doped (UID) n-type bulk conductivity. Films grown at the highest substrate temperatures with excess In had the lowest electron concentration and highest electron mobility. The UID electron concentration was shown to originate from impurity incorporation. A correlation between electron concentration and dislocation density was not observed, but dislocations were shown to limit the electron mobility in the InN films. The control of n-type conductivity in InN was demonstrated using a combination of Si-doping, variable growth temperature, and Mg-doping. The electron concentrations were controlled over a range of three orders of magnitude, with Mg-doped films demonstrating bulk electron

  16. Structural studies in the epitaxial-growth of indium nitride crystals with flower-like structure on a sapphire (112¯0) substrate

    NASA Astrophysics Data System (ADS)

    Wakasugi, Satoshi; Sugiura, Haruka; Shimomura, Masaru; Nakamura, Takato; Takahashi, Naoyuki

    2007-11-01

    Indium nitride crystals with flower-like structure are grown on a-plane sapphire substrate by means of chemical vapor deposition using InCl 3 and NH 3 as starting materials under atmospheric pressure. They have similar shape and size. It was found that a style and petals which constitute flower-like structure were grown homoepitaxially. This was deduced by the results of the reciprocal space mappings. Also, it was suggested that there are the following relationships between the style and petals: the directions [//[ and [//[//[ are parallel and perpendicular to the substrate, respectively. Selective growth of the flower-like InN crystals is explained in terms of the homoepitaxy.

  17. Optical, structural, and transport properties of indium nitride, indium gallium nitride alloys grown by metalorganic chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Khan, Neelam

    InGaN based, blue and green light emitting diodes (LEDs) have been successfully produced over the past decade. But the progress of these LEDs is often limited by the fundamental problems of InGaN such as differences in lattice constants, thermal expansion coefficients and physical properties between InN and GaN. This difficulty could be addressed by studying pure InN and InxGa 1-xN alloys. In this context Ga-rich InxGa1-xN (x ≤ 0.4) epilayers were grown by metal organic chemical vapor deposition (MOCVD). X-ray diffraction (XRD) measurements showed InxGa1-xN films with x= 0.37 had single phase. Phase separation occurred for x ˜ 0.4. To understand the issue of phase separation in Ga-rich InxGa 1-xN, studies on growth of pure InN and In-rich InxGa 1-xN alloys were carried out. InN and In-rich InxGa1-xN (x ˜ 0.97-0.40) epilayers were grown on AlN/Al2O3 templates. A Hall mobility of 1400 cm2/Vs with a carrier concentration of 7x1018cm -3 was observed for InN epilayers grown on AlN templates. Photoluminescence (PL) emission spectra revealed a band to band emission peak at ˜0.75 eV for InN. This peak shifted to 1.15 eV when In content was varied from 1.0 to 0.63 in In-rich InxGa1-xN epilayers. After growth parameter optimization of In-rich InxGa1-xN alloys with (x = 0.97-0.40) were successfully grown without phase separation. Effects of Mg doping on the PL properties of InN epilayers grown on GaN/Al 2O3 templates were investigated. An emission line at ˜ 0.76 eV, which was absent in undoped InN epilayers and was about 60 meV below the band edge emission peak at ˜ 0.82 eV, was observed to be the dominant emission in Mg-doped InN epilayers. PL peak position and the temperature dependent emission intensity corroborated each other and suggested that Mg acceptor level in InN is about 60 meV above the valance band maximum. Strain effects on the emission properties of InGaN/GaN multiple quantum wells (MQWs) were studied using a single blue LED wafer possessing a continuous

  18. Enhancement of polycrystalline silicon solar cells efficiency using indium nitride particles

    NASA Astrophysics Data System (ADS)

    Alkis, Sabri; Imtiaz Chowdhury, Farsad; Alevli, Mustafa; Dietz, Nikolaus; Yalızay, Berna; Aktürk, Selçuk; Nayfeh, Ammar; Kemal Okyay, Ali

    2015-10-01

    In this work, we present a hybrid indium nitride particle/polycrystalline silicon solar cell based on 230 nm size indium nitride particles (InN-Ps) obtained through laser ablation. The solar cell performance measurements indicate that there is an absolute 1.5% increase (Δη) in the overall solar cell efficiency due to the presence of InN-Ps. Within the spectral range 300-1100 nm, improvements of up to 8.26% are observed in the external quantum efficiency (EQE) and increases of up to 8.75% are observed in the internal quantum efficiency (IQE) values of the corresponding solar cell. The enhancement in power performance is due to the down-shifting properties of the InN-Ps. The electrical measurements are supplemented by TEM, Raman, UV/VIS and PL spectroscopy of the InN-Ps.

  19. Plasma deposited silicon nitride for indium phosphide encapsulation

    NASA Technical Reports Server (NTRS)

    Valco, G. J.; Kapoor, V. J.; Biedenbender, M. D.; Williams, W. D.

    1989-01-01

    The composition and the annealing characteristics of plasma-deposited silicon-nitride encapsulating films on the ion-implanted InP substrates were investigated, using two different substrate-cleaning procedures (organic solvents and HF or HIO3 solutions) prior to encapsulation. The effect of plasma deposition of silicon nitride on the InP substrates was assessed through the current-voltage characteristics of Schottky diodes. Results of XPS analyses showed that the cleaning procedure that employed HF solution left less oxygen on the InP surface than the procedure involving HIO3. No chemical interaction between the film and the substrate was observed before or after annealing.

  20. Plasma deposited silicon nitride for indium phosphide encapsulation

    NASA Technical Reports Server (NTRS)

    Valco, G. J.; Kapoor, V. J.; Biedenbender, M. D.; Williams, W. D.

    1989-01-01

    The composition and the annealing characteristics of plasma-deposited silicon-nitride encapsulating films on the ion-implanted InP substrates were investigated, using two different substrate-cleaning procedures (organic solvents and HF or HIO3 solutions) prior to encapsulation. The effect of plasma deposition of silicon nitride on the InP substrates was assessed through the current-voltage characteristics of Schottky diodes. Results of XPS analyses showed that the cleaning procedure that employed HF solution left less oxygen on the InP surface than the procedure involving HIO3. No chemical interaction between the film and the substrate was observed before or after annealing.

  1. InN thin-film transistors fabricated on polymer sheets using pulsed sputtering deposition at room temperature

    NASA Astrophysics Data System (ADS)

    Lye, Khe Shin; Kobayashi, Atsushi; Ueno, Kohei; Ohta, Jitsuo; Fujioka, Hiroshi

    2016-07-01

    Indium nitride (InN) is potentially suitable for the fabrication of high performance thin-film transistors (TFTs) because of its high electron mobility and peak electron velocity. However, InN is usually grown using a high temperature growth process, which is incompatible with large-area and lightweight TFT substrates. In this study, we report on the room temperature growth of InN films on flexible polyimide sheets using pulsed sputtering deposition. In addition, we report on the fabrication of InN-based TFTs on flexible polyimide sheets and the operation of these devices.

  2. InN thin-film transistors fabricated on polymer sheets using pulsed sputtering deposition at room temperature

    SciTech Connect

    Lye, Khe Shin; Kobayashi, Atsushi; Ueno, Kohei; Ohta, Jitsuo; Fujioka, Hiroshi

    2016-07-18

    Indium nitride (InN) is potentially suitable for the fabrication of high performance thin-film transistors (TFTs) because of its high electron mobility and peak electron velocity. However, InN is usually grown using a high temperature growth process, which is incompatible with large-area and lightweight TFT substrates. In this study, we report on the room temperature growth of InN films on flexible polyimide sheets using pulsed sputtering deposition. In addition, we report on the fabrication of InN-based TFTs on flexible polyimide sheets and the operation of these devices.

  3. Effects of substrate nitridation and buffer layer on the crystalline improvements of semi-polar InN(101¯3) crystal on GaAs(110) by MOVPE

    NASA Astrophysics Data System (ADS)

    Cho, H. C.; Togashi, R.; Murakami, H.; Kumagai, Y.; Koukitu, A.

    2013-03-01

    In this report, effects of ammonia nitridation and low temperature InN buffer growth were investigated to improve the crystalline quality of InN(101¯3) grown on GaAs(110) by metalorganic vapor phase epitaxy (MOVPE). InN(101¯3) single crystal including less than 0.1% of differently oriented domains was successfully grown by inserting low temperature InN buffer layer. The full width at half maximum (FWHM) values of InN(101¯3) epitaxial layer were drastically decreased from 89 arcmin to 55 arcmin after processing ammonia nitridation of GaAs(110) substrate surface. Furthermore, the FWHM value was decreased to 38 arcmin by increasing growth time, and the mechanism of dislocation annihilation happened during epitaxial growth was discussed.

  4. Metalorganic chemical vapor deposition of indium nitride and indium gallium nitride thin films and nanostructures for electronic and photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Mangum, Joshua L.

    Single and multi-junction InxGa1-xN solar cell devices were modeled in one dimension using MEDICI device simulation software to assess the potential of InxGa1-xN-based solar cells. Cell efficiencies of 16 and 27.4%, under AM0 illumination were predicted for a single and a 5-junction InxGa1-xN solar cell, respectively. Phase separation of InxGa1-xN alloys is determined to have little to no negative effects on the solar cell efficiency. InxGa1-xN alloys were grown by MOCVD over the entire compositional range (0 ≤ x ≤ 1) and phase separation was analyzed with respect to substrate material and growth temperature. A low deposition temperature of 530°C was used to produce metastable InxGa1-xN/c-Al 2O3 thin films over the entire compositional range, which was demonstrated for the first time by MOCVD. The use of higher deposition temperature and closely lattice matched substrates resulted in phase separated films. Substrates with a larger lattice mismatch (c-Al2O3 ) introduce strain in InxGa1-xN which helps to stabilize the film, however, at the expense of crystalline quality. Growth of InN nanowires by MOCVD was controlled without the use of templates or catalysts by varying the inlet flow pattern, N/In ratio, growth temperature, and substrate material. A VLS growth mechanism is proposed, however, a VS growth mechanism can be achieved at high N/In ratios. SEM and TEM analysis revealed a core-shell nanowire structure with a single crystal InN core and a poly-crystalline In2O3 shell. Nanowire growth occurs along the [0002] direction with diameters and lengths ranging from 100 to 300 nm and 10 to 40 mum, respectively for a 1 hr growth. H-MOCVD growth of InN nano- and microrods occurred on different substrates and the nanorod structure was studied by TEM. The polarity of the substrate directly affected the nanorod tip shape and prismatic stacking faults are suggested as the cause for the flower-like growth habit. Variation of growth parameters, such as temperature, N

  5. Influence of In-N Clusters on Band Gap Energy of Dilute Nitride In x Ga1-x N y As1-y

    NASA Astrophysics Data System (ADS)

    Zhao, Chuan-Zhen; Guo, Heng-Fei; Chen, Li-Ying; Tang, Chun-Xiao; Lu, Ke-Qing

    2016-05-01

    The In-N clusters form in the dilute nitride InxGa1-xNyAs1-y alloys after annealing. It is found that the formation of the In-N clusters not only raises the N levels lying above the conduction band minimum (CBM) of InGaAs, but also raises the N levels below the CBM of InGaAs, leading to the variation of the impurity-host interaction. The blueshift of the band gap energy is relative to the variation of the impurity-host interaction. In order to describe the blueshift of the band gap energy due to the formation of the In-N clusters, a model is developed. It is found that the model can describe the blueshift of the band gap energy well. In addition, it is found the blueshift of the band gap energy due to the atom interdiffusion at the interface can be larger than that due to the formation of the In-N clusters. Supported by the National Natural Science Foundation of China under Grant No. 61504094, Tinjin Research Program of Application Foundation and Advanced Technology under No. 15JCYBJC16300, and Tianjin City High School Science and Technology Fund Planning Project No. 20120609

  6. InN Based Water Condensation Sensors on Glass and Flexible Plastic Substrates

    PubMed Central

    Dumitru, Viorel; Costea, Stefan; Brezeanu, Mihai; Stan, George E.; Besleaga, Cristina; Galca, Aurelian C.; Ionescu, Gabriela; Ionescu, Octavian

    2013-01-01

    In this paper, we report the realization and characterization of a condensation sensor based on indium nitride (InN) layers deposited by magnetron sputtering on glass and flexible plastic substrates, having fast response and using potentially low cost fabrication technology. The InN devices work as open gate thin film sensitive transistors. Condensed water droplets, formed on the open gate region of the sensors, deplete the electron accumulation layer on the surface of InN film, thus decreasing the current of the sensor. The current increases back to its initial value when water droplets evaporate from the exposed InN film surface. The response time is as low as 2 s.

  7. Catalyst-free Indium Nitride Nanostructures Grown by Plasma-Assisted MOCVD

    NASA Astrophysics Data System (ADS)

    Norman, Dever; Hamad, Samir; Seo, Hye-Won

    2010-03-01

    The growth of Indium Nitride nanostructures directly on n-type Si (111) substrate was achieved without ammonia using nitrogen plasma as sole atomic nitrogen contribution. In this study we determine the growth conditions for optimal structural characteristics adjusting plasma generation power, substrate temperature, and III/V ratio. The structures formed nucleation sites directly interspersed on Si substrate without the use of hetero catalysis. SEM observations show that structurally the nanostructures range from narrow and horizontal with a high 1-dimensional consistency in width and length, to vertical and conical. Effects of the growth parameters along with the growth mechanism of nanostructures will be discussed.

  8. Nanoscale optical properties of indium gallium nitride/gallium nitride nanodisk-in-rod heterostructures.

    PubMed

    Zhou, Xiang; Lu, Ming-Yen; Lu, Yu-Jung; Jones, Eric J; Gwo, Shangjr; Gradečak, Silvija

    2015-03-24

    III-nitride based nanorods and nanowires offer great potential for optoelectronic applications such as light emitting diodes or nanolasers. We report nanoscale optical studies of InGaN/GaN nanodisk-in-rod heterostructures to quantify uniformity of light emission on the ensemble level, as well as the emission characteristics from individual InGaN nanodisks. Despite the high overall luminescence efficiency, spectral and intensity inhomogeneities were observed and directly correlated to the compositional variations among nanodisks and to the presence of structural defect, respectively. Observed light quenching is correlated to type I1 stacking faults in InGaN nanodisks, and the mechanisms for stacking fault induced nonradiative recombinations are discussed in the context of band structure around stacking faults and Fermi level pinning at nanorod surfaces. Our results highlight the importance of controlling III-nitride nanostructure growths to further reduce defect formation and ensure compositional homogeneity for optoelectronic devices with high efficiencies and desirable spectrum response.

  9. Epitaxial growth of III-V nitrides and phase separation and ordering in indium gallium nitride alloys

    NASA Astrophysics Data System (ADS)

    Doppalapudi, Dharanipal

    The family of III-V nitrides are wide band-gap semiconductors with a broad range of opto-electronic applications in LEDs, laser diodes, UV detectors as well as high temperature/high frequency devices. Due to the lack of good quality native substrates, GaN is grown on foreign substrates that have a lattice and thermal mismatch with GaN. This results in a material with a high density of defects, which in turn adversely affects the opto-electronic properties of the epilayer. In this study, GaN films were epitaxially grown on various substrates (C-plane sapphire, A-plane sapphire, SiC and ZnO) by molecular beam epitaxy. Additionally, GaN homoepitaxy onto laterally overgrown thick GaN substrates was investigated. It was demonstrated that the polarity of the GaN film plays a major role in determining the properties of the films. The growth parameters were optimized to eliminate inversion domain boundaries, which result in domains of opposite polarity in the GaN lattice. For growth on A-plane sapphire, it was found that substrate nitridation and low temperature buffer deposition are critical in order to obtain good epitaxial growth, in spite of the relatively small mismatch between the film and substrate. A crystallographic model was developed to explain this observation. By optimizing growth parameters, GaN films with excellent structural, transport, optical and device properties were grown. The second part of this research involves growth of ternary alloys and superlattice structures, which are essential in the fabrication of many devices. It was found that the InN-GaN pseudo-binary system is not homogeneous over the entire composition range. Due to the mismatch between the tetrahedral radii of GaN and InN, InGaN alloys exhibited phase separation and long-range atomic ordering. Investigations of InxGa1-xN films grown over a wide range of compositions by XRD and TEM showed that the predominant strain relieving mechanism was phase separation in films with x > 0.2, and

  10. ANALYSIS OF THE WATER-SPLITTING CAPABILITIES OF GALLIUM INDIUM PHOSPHIDE NITRIDE (GaInPN)

    SciTech Connect

    Head, J.; Turner, J.

    2007-01-01

    With increasing demand for oil, the fossil fuels used to power society’s vehicles and homes are becoming harder to obtain, creating pollution problems and posing hazard’s to people’s health. Hydrogen, a clean and effi cient energy carrier, is one alternative to fossil fuels. Certain semiconductors are able to harness the energy of solar photons and direct it into water electrolysis in a process known as photoelectrochemical water-splitting. P-type gallium indium phosphide (p-GaInP2) in tandem with GaAs is a semiconductor system that exhibits water-splitting capabilities with a solar-tohydrogen effi ciency of 12.4%. Although this material is effi cient at producing hydrogen through photoelectrolysis it has been shown to be unstable in solution. By introducing nitrogen into this material, there is great potential for enhanced stability. In this study, gallium indium phosphide nitride Ga1-yInyP1-xNx samples were grown using metal-organic chemical vapor deposition in an atmospheric-pressure vertical reactor. Photocurrent spectroscopy determined these materials to have a direct band gap around 2.0eV. Mott-Schottky analysis indicated p-type behavior with variation in fl atband potentials with varied frequencies and pH’s of solutions. Photocurrent onset and illuminated open circuit potential measurements correlated to fl atband potentials determined from previous studies. Durability analysis suggested improved stability over the GaInP2 system.

  11. Indium

    SciTech Connect

    Carlin, J.F.

    1985-01-01

    Indium occurs as a trace constituent of other metal deposits, principally zinc, but also lead, tin, tungsten, and iron. It is derived as a byproduct usually from residues generating in the refining of zinc, so its supply is therefore dependent upon demand for and, hence, the production of that metal. It is estimated that 90% of the U.S. requirements for indium are accounted for by imports of highly refined indium metal or indium-rich residues and other materials, mainly from France, Italy, Belgium, and the United Kingdom. Dependence on foreign sources is expected to continue. The principal producers of refined indium metal are the United States, Belgium, Japan, France, and Italy. The major uses of indium are in alloys and instruments, and the metal has applications in a variety of other fields. There are potential substitutes for indium in many of its applications. Domestic indium demand was estimated at 700,000 troy ounces in 1983. Based on a contingency analysis of the major end uses for indium, the range of possible domestic demands for primary indium in the year 2000 is forecast to be from 500,000 to 1,100,000 ounces. A probable demand of 900,000 ounces represents an annual growth rate of 1.5%. The range of demand forecasts for the rest of the world is between 1.0 million and 1.9 million ounces, with a probable demand of 1.7 million ounces, which represents an annual growth rate of 1.6%.

  12. Distinctive signature of indium gallium nitride quantum dot lasing in microdisk cavities

    PubMed Central

    Woolf, Alexander; Puchtler, Tim; Aharonovich, Igor; Zhu, Tongtong; Niu, Nan; Wang, Danqing; Oliver, Rachel; Hu, Evelyn L.

    2014-01-01

    Low-threshold lasers realized within compact, high-quality optical cavities enable a variety of nanophotonics applications. Gallium nitride 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 use the distinctive, high-quality (Q∼5,500) modes of the cavities, and the change in the highest-intensity mode as a function of pump power to better understand the dominant radiative processes. The variations of threshold power and lasing wavelength as a function of gain medium help us identify the possible limitations to lower-threshold lasing with quantum dot active medium. In addition, we have identified a distinctive lasing signature for quantum dot materials, which consistently lase at wavelengths shorter than the peak of the room temperature gain emission. These findings not only provide better understanding of lasing in nitride-based quantum dot cavity systems but also shed insight into the more fundamental issues of light−matter coupling in such systems. PMID:25197073

  13. Distinctive signature of indium gallium nitride quantum dot lasing in microdisk cavities.

    PubMed

    Woolf, Alexander; Puchtler, Tim; Aharonovich, Igor; Zhu, Tongtong; Niu, Nan; Wang, Danqing; Oliver, Rachel; Hu, Evelyn L

    2014-09-30

    Low-threshold lasers realized within compact, high-quality optical cavities enable a variety of nanophotonics applications. Gallium nitride 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 use the distinctive, high-quality (Q ∼ 5,500) modes of the cavities, and the change in the highest-intensity mode as a function of pump power to better understand the dominant radiative processes. The variations of threshold power and lasing wavelength as a function of gain medium help us identify the possible limitations to lower-threshold lasing with quantum dot active medium. In addition, we have identified a distinctive lasing signature for quantum dot materials, which consistently lase at wavelengths shorter than the peak of the room temperature gain emission. These findings not only provide better understanding of lasing in nitride-based quantum dot cavity systems but also shed insight into the more fundamental issues of light-matter coupling in such systems.

  14. Large area InN terahertz emitters based on the lateral photo-Dember effect

    SciTech Connect

    Wallauer, Jan Grumber, Christian; Walther, Markus; Polyakov, Vladimir; Iannucci, Robert; Cimalla, Volker; Ambacher, Oliver

    2015-09-14

    Large area terahertz emitters based on the lateral photo-Dember effect in InN (indium nitride) are presented. The formation of lateral photo-Dember currents is induced by laser-illumination through a microstructured metal cover processed onto the InN substrate, causing an asymmetry in the lateral photogenerated charge carrier distribution. Our design uses simple metal structures, which are produced by conventional two-dimensional micro-structuring techniques. Having favoring properties as a photo-Dember material InN is particularly well-suited as a substrate for our emitters. We demonstrate that the emission intensity of the emitters can be significantly influenced by the structure of the metal cover leaving room for improvement by optimizing the masking structures.

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

    SciTech Connect

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

    2014-09-21

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

  16. Indium gallium nitride/gallium nitride vacuum microelectronic cold cathodes: Piezoelectric surface barrier lowering

    NASA Astrophysics Data System (ADS)

    Underwood, Robert Douglas

    Vacuum microelectronic devices are electronic devices fabricated using microelectronic processing and using vacuum as a transport medium. The electron velocity in vacuum can be larger than in solid state, which allows higher frequency operation of vacuum devices compared to solid-state devices. The effectiveness of vacuum microelectronic devices relies on the realization of an efficient source of electrons supplied to the vacuum. Cold cathodes do not rely on thermal energy for the emission of electrons into vacuum. Cold cathodes based on field emission are the most common types of vacuum microelectronic cold cathode because they have a very high efficiency and high current density electron emission. Materials used to fabricate field emitters must have the properties of high electron concentration, low surface reactivity, resistance to sputtering by ions, high thermal conductivity, and a method of fabrication of uniform arrays of field emitters. The III--V nitride semiconductors possess these material properties and uniform arrays of GaN field emitter pyramids have been produced by selective area, self-limited metalorganic chemical vapor deposition. The first GaN field emitter arrays were fabricated and measured. Emission currents as large as 82 muA at 1100 V from 245,000 pyramids have been realized using an external anode, separated by 0.25 mm, to apply voltage bias. The operation voltage was reduced by the development of an integrated anode structure. The anode-cathode separation achievable with the integrated anode was in the range of 0.5--2.4 m. The turn-on voltages of these devices were reduced to the range of 175--435 V. The operation voltage of field emitter cathodes is related to the surface energy barrier, which for n-type semiconductors is the electron affinity. A new method to reduce the effective electron affinity using a piezoelectric dipole in an InGaN/GaN heterostructure has been proposed and tested. The piezoelectric field produced in the strained In

  17. Effect of strain on gallium nitride and gallium indium arsenide nitride growth and doping

    NASA Astrophysics Data System (ADS)

    G. S., Sudhir

    GaN and the related (Al,In)N materials are currently used in manufacturing optoelectronic and electronic devices. However, the efficiency of these devices is limited due to lack of high structural quality and of low resistive p-type GaN. The GaN thin films are under strain during growth due to the large lattice mismatch, thermal expansion difference, and low growth temperature. Developing a better understanding of the effect of strain on the properties of thin films is important in furthering our knowledge of thin film growth affecting the performance of III-nitride based devices. Pulsed laser deposition was used to grow thin films of AlN and GaN on sapphire substrates. It is shown that the structure and surface morphology of layers are controlled by the nitrogen partial pressure during the growth. Through these nitrogen pressure related effects, thin films with microstructure ranging from crystalline to amorphous can be produced. A minimal surface root mean square roughness of 0.7 nm for amorphous AlN is obtained which compares well with the substrate roughness of 0.5 nm. Incorporation of impurities changes the lattice constants of thin films of GaN deposited on basal plane sapphire by molecular beam epitaxy. Both Mg (1017 cm-3) and Zn (3 x 10 20 cm-3) doping were found to expand the c lattice parameter by +0.38 x 10-2 and +0.62 x 10 -2, respectively. Oxygen up to concentrations 9 x 10 21 cm-3 is shown to replace nitrogen in GaN thin films reducing the c parameter only by a small amount. Incorporation of Si leads to a large decrease of the c parameter, which can not be attributed to the different size of Ga and Si. It is suggested that doping alters the film stoichiometry by a predicted Fermi level dependence of defect formation energies and thereby, lattice parameters and stress. A proper buffer layer design is shown to increase the incorporation of Mg by two orders of magnitude Finally, the balance of lattice parameter change caused by dopant and native point

  18. Periodic supply of indium as surfactant for N-polar InN growth by plasma-assisted molecular-beam epitaxy

    NASA Astrophysics Data System (ADS)

    Yao, Yong-Zhao; Sekiguchi, Takashi; Ohgaki, Takeshi; Adachi, Yutaka; Ohashi, Naoki; Okuno, Hanako; Takeguchi, Masaki

    2009-07-01

    We have investigated the self-surfactant effect of In for N-polar InN growth by plasma-assisted molecular-beam epitaxy. We found that InN quality was significantly improved if a thin In coverage (about 1.8 ML) was introduced before InN growth. However, this In coverage was slowly consumed during subsequent InN growth under N-rich condition. Periodically restoring In coverage for thick InN growth was proposed to solve this consumption problem. We suggest that the effect of In surfactant is to terminate the surface N dangling bonds and form an In adlayer, under which an efficient diffusion channel for lateral N adatom transport is created.

  19. Micro and nano-structured green gallium indium nitride/gallium nitride light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Stark, Christoph J. M.

    Light-emitting diodes (LEDs) are commonly designed and studied based on bulk material properties. In this thesis different approaches based on patterns in the nano and micrometer length scale range are used to tackle low efficiency in the green spectral region, which is known as “green gap”. Since light generation and extraction are governed by microscopic processes, it is instructive to study LEDs with lateral mesa sizes scaled to the nanometer range. Besides the well-known case of the quantum size effect along the growth direction, a continuous lateral scaling could reveal the mechanisms behind the purported absence of a green gap in nanowire LEDs and the role of their extraction enhancement. Furthermore the possibility to modulate strain and piezoelectric polarization by post growth patterning is of practical interest, because the internal electric fields in conventional wurtzite GaN LEDs cause performance problems. A possible alternative is cubic phase GaN, which is free of built-in polarization fields. LEDs on cubic GaN could show the link between strong polarization fields and efficiency roll-off at high current densities, also known as droop. An additional problem for all nitride-based LEDs is efficient light extraction. For a planar GaN LED only roughly 8% of the generated light can be extracted. Novel lightextraction structures with extraction-favoring geometry can yield significant increase in light output power. To investigate the effect of scaling the mesa dimension, micro and nano-sized LED arrays of variable structure size were fabricated. The nano-LEDs were patterned by electron beam lithography and dry etching. They contained up to 100 parallel nano-stripe LEDs connected to one common contact area. The mesa width was varied over 1 μm, 200 nm, and 50 nm. These LEDs were characterized electrically and optically, and the peak emission wavelength was found to depend on the lateral structure size. An electroluminescence (EL) wavelength shift of 3 nm

  20. Enhanced light harvesting of nitride-based nanopillars covered with ZnO using indium-tin oxide nanowhiskers

    NASA Astrophysics Data System (ADS)

    Hsu, Lung-Hsing; Lin, Chien-Chung; Lee, Hsin-Ying; Huang, Jhih-Kai; Han, Hau-Vei; Tsai, Yu-Lin; Yu, Peichen; Kuo, Hao-Chung; Lee, Ching-Ting

    2014-01-01

    Nitride-based nanopillars were successfully fabricated by nanoimprint lithography. A nanowhisker of indium-tin oxide (ITO) deposited by on oblique evaporation method was investigated in nitride-based nanopillars and thin ZnO layers grown by atomic layer deposition (ALD). From the results of field-emission scanning electron microscopy (SEM) measurement, it was found that ITO whiskers grew on nitride-based nanopillars covered with ZnO. Moreover, from the results of UV-visible spectrophotometry and bidirectional reflectance distribution function (BRDF) measurements, it was found that this hybrid structure of ITO nanowhiskers above a ZnO medium enhanced the broadband and angle-independent antireflection in the range between 380 and 600 nm. We used the hybrid design of the ITO/ZnO structure to achieve the lowest reflectance value between 3.8 and 10.9% in a quantum well absorption range.

  1. Enhanced efficiency of Schottky-barrier solar cell with periodically nonhomogeneous indium gallium nitride layer

    NASA Astrophysics Data System (ADS)

    Anderson, Tom H.; Mackay, Tom G.; Lakhtakia, Akhlesh

    2017-01-01

    A two-dimensional finite-element model was developed to simulate the optoelectronic performance of a Schottky-barrier solar cell. The heart of this solar cell is a junction between a metal and a layer of n-doped indium gallium nitride (InξGaN) alloy sandwiched between a reflection-reducing front window and a periodically corrugated metallic back reflector. The bandgap of the InξGaN layer was varied periodically in the thickness direction by varying the parameter ξ∈(0,1). First, the frequency-domain Maxwell postulates were solved to determine the spatial profile of photon absorption and, thus, the generation of electron-hole pairs. The AM1.5G solar spectrum was taken to represent the incident solar flux. Next, the drift-diffusion equations were solved for the steady-state electron and hole densities. Numerical results indicate that a corrugated back reflector of a period of 600 nm is optimal for photon absorption when the InξGaN layer is homogeneous. The efficiency of a solar cell with a periodically nonhomogeneous InξGaN layer may be higher by as much as 26.8% compared to the analogous solar cell with a homogeneous InξGaN layer.

  2. Unusual strategies for using indium gallium nitride grown on silicon (111) for solid-state lighting

    PubMed Central

    Kim, Hoon-sik; Brueckner, Eric; Song, Jizhou; Li, Yuhang; Kim, Seok; Lu, Chaofeng; Sulkin, Joshua; Choquette, Kent; Huang, Yonggang; Nuzzo, Ralph G.; Rogers, John A.

    2011-01-01

    Properties that can now be achieved with advanced, blue indium gallium nitride light emitting diodes (LEDs) lead to their potential as replacements for existing infrastructure in general illumination, with important implications for efficient use of energy. Further advances in this technology will benefit from reexamination of the modes for incorporating this materials technology into lighting modules that manage light conversion, extraction, and distribution, in ways that minimize adverse thermal effects associated with operation, with packages that exploit the unique aspects of these light sources. We present here ideas in anisotropic etching, microscale device assembly/integration, and module configuration that address these challenges in unconventional ways. Various device demonstrations provide examples of the capabilities, including thin, flexible lighting “tapes” based on patterned phosphors and large collections of small light emitters on plastic substrates. Quantitative modeling and experimental evaluation of heat flow in such structures illustrates one particular, important aspect of their operation: small, distributed LEDs can be passively cooled simply by direct thermal transport through thin-film metallization used for electrical interconnect, providing an enhanced and scalable means to integrate these devices in modules for white light generation. PMID:21666096

  3. Surface cleaning procedures for thin films of indium gallium nitride grown on sapphire

    NASA Astrophysics Data System (ADS)

    Douglass, K.; Hunt, S.; Teplyakov, A.; Opila, R. L.

    2010-12-01

    Surface preparation procedures for indium gallium nitride (InGaN) thin films were analyzed for their effectiveness for carbon and oxide removal as well as for the resulting surface roughness. Aqua regia (3:1 mixture of concentrated hydrochloric acid and concentrated nitric acid, AR), hydrofluoric acid (HF), hydrochloric acid (HCl), piranha solution (1:1 mixture of sulfuric acid and 30% H 2O 2) and 1:9 ammonium sulfide:tert-butanol were all used along with high temperature anneals to remove surface contamination. X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were utilized to study the extent of surface contamination and surface roughness, respectively. The ammonium sulfide treatment provided the best overall removal of oxygen and carbon. Annealing over 700 °C after a treatment showed an even further improvement in surface contamination removal. The piranha treatment resulted in the lowest residual carbon, while the ammonium sulfide treatment leads to the lowest residual oxygen. AFM data showed that all the treatments decreased the surface roughness (with respect to as-grown specimens) with HCl, HF, (NH 4) 2S and RCA procedures giving the best RMS values (˜0.5-0.8 nm).

  4. Unusual strategies for using indium gallium nitride grown on silicon (111) for solid-state lighting.

    PubMed

    Kim, Hoon-sik; Brueckner, Eric; Song, Jizhou; Li, Yuhang; Kim, Seok; Lu, Chaofeng; Sulkin, Joshua; Choquette, Kent; Huang, Yonggang; Nuzzo, Ralph G; Rogers, John A

    2011-06-21

    Properties that can now be achieved with advanced, blue indium gallium nitride light emitting diodes (LEDs) lead to their potential as replacements for existing infrastructure in general illumination, with important implications for efficient use of energy. Further advances in this technology will benefit from reexamination of the modes for incorporating this materials technology into lighting modules that manage light conversion, extraction, and distribution, in ways that minimize adverse thermal effects associated with operation, with packages that exploit the unique aspects of these light sources. We present here ideas in anisotropic etching, microscale device assembly/integration, and module configuration that address these challenges in unconventional ways. Various device demonstrations provide examples of the capabilities, including thin, flexible lighting "tapes" based on patterned phosphors and large collections of small light emitters on plastic substrates. Quantitative modeling and experimental evaluation of heat flow in such structures illustrates one particular, important aspect of their operation: small, distributed LEDs can be passively cooled simply by direct thermal transport through thin-film metallization used for electrical interconnect, providing an enhanced and scalable means to integrate these devices in modules for white light generation.

  5. MBE Growth of InN/GaN(0001) and Shape Transitions of InN islands

    NASA Astrophysics Data System (ADS)

    Cao, Yongge; Xie, Maohai; Liu, Ying; Ng, Y. F.

    2003-03-01

    Plasma-assisted molecular-beam epitaxial growth of InN on GaN(0001) is investigated. Both layer-by-layer and Stranski-Krastanov (SK) growth modes are observed under different growth windows. Strain relaxation is studied by real-time recording of the in-plane lattice spacing evolutions on RHEED pattern, which suggest a gradual relaxation of the strain in InN film commenced during the first bilayer (BL) deposition and almost completed after 2-4 BLs. For SK growth, 3D islanding initiates after the strain has mostly been relieved, presumably by dislocations. Based on statistical analysis, the shape transitions of 3D islands are firstly observed in the III-nitrides system. The InN islands transform gradually from pyramids to platelets with increasing of In flux. Under In-rich growth condition, the reverse trend of island shape evolution dependence on volume size, compared with Equilibrium Crystal Shape (ECS) theory, is induced by the Indium self-surfactant effects, in which Indium adlayer on the top surface of InN islands will depress the thermodynamic driving force for the vertical growth of 3D islands. Lateral growth of 3D islands is not only the result of kinetic process but also favored by thermodynamics while Indium self-surfactant exist.

  6. Wavelength-multiplexed pumping with 478- and 520-nm indium gallium nitride laser diodes for Ti:sapphire laser.

    PubMed

    Sawada, Ryota; Tanaka, Hiroki; Sugiyama, Naoto; Kannari, Fumihiko

    2017-02-20

    We experimentally reveal the pump-induced loss in a Ti:sapphire laser crystal with 451-nm indium gallium nitride (InGaN) laser diode pumping and show that 478-nm pumping can reduce such loss. The influence of the pump-induced loss at 451-nm pumping is significant even for a crystal that exhibits higher effective figure-of-merit and excellent laser performance at 520-nm pumping. We demonstrate the power scaling of a Ti:sapphire laser by combining 478- and 520-nm InGaN laser diodes and obtain CW output power of 593 mW.

  7. In induced reconstructions of Si(1 1 1) as superlattice matched epitaxial templates for InN growth

    SciTech Connect

    Kuyyalil, Jithesh; Tangi, Malleswararao; Shivaprasad, S.M.

    2013-02-15

    Graphical abstract: Display Omitted Highlights: ► A novel growth method to form InN at low growth temperatures. ► Use of Si reconstruction as a growth template for group III nitrides. ► Band gap variation of InN – Moss–Burstein shift – non-parabolic conduction band for InN. ► Super lattice matching epitaxy of metal induced reconstructions with III–V unit cell. -- Abstract: Indium induced surface reconstructions of Si(1 1 1)-7 × 7 are used as templates to grow high quality InN. We grow InN on Si(1 1 1)-7 × 7, Si(1 1 1)-4 × 1-In and Si(1 1 1)-1 × 1-In reconstructed surfaces and study the quality of the films formed using complementary characterization tools. InN grown on Si(1 1 1)-1 × 1-In reconstruction shows superior film quality with lowest band-edge emission having a narrow full width at half maximum, intense and narrow 0 0 0 2 X-ray diffraction, low surface roughness and carrier concentration an order lower than other samples. We attribute the high quality of the film formed at 300 °C to the integral matching of InN and super lattice dimensions, we also study the reasons for the band gap variation of InN in the literature. Present study demonstrates the proposed Superlattice Matched Epitaxy can be a general approach to grow good quality InN at much lower growth temperature on compatible In induced reconstructions of the Si surface.

  8. Initial exploration of growth of InN by electrochemical solution growth.

    SciTech Connect

    Waldrip, Karen Elizabeth

    2010-02-01

    This report summarizes a brief and unsuccessful attempt to grow indium nitride via the electrochemical solution growth method and a modification thereof. Described in this report is a brief effort using a $50,000 LDRD award to explore the possibilities of applying the Electrochemical Solution Growth (ESG) technique to the growth of indium nitride (InN). The ability to grow bulk InN would be exciting from a scientific perspective, and a commercial incentive lies in the potential of extending the ESG technique to grow homogeneous, bulk alloys of In{sub x}Ga{sub 1-x}N for light emitting diodes (LEDs) operating in the green region of the spectrum. Indium nitride is the most difficult of the III-nitrides to grow due to its very high equilibrium vapor pressure of nitrogen1. It is several orders of magnitude higher than for gallium nitride or aluminum nitride. InN has a bandgap energy of 0.7eV, and achieving its growth in bulk for large area, high quality substrates would permit the fabrication of LEDs operating in the infrared. By alloying with GaN and AlN, the bulk material used as substrates would enable high efficiency emission wavelengths that could be tailored all the way through the deep ultraviolet. In addition, InN has been shown to have very high electronic mobilities (2700 cm{sup 2}/V s), making it a promising material for transistors and even terahertz emitters. Several attempts at synthesizing InN have been made by several groups. It was shown that metallic indium does not interact with unactivated nitrogen even at very high temperatures. Thus sets up an incompatibility between the precursors in all growth methods: a tradeoff between thermally activating the nitrogen-containing precursor and the low decomposition temperature of solid InN. We have been working to develop a novel growth technique that circumvents the difficulties of other bulk growth techniques by precipitating the column III nitrides from a solvent, such as a molten chloride salt, that

  9. Self-Catalyzed Growth of Vertically Aligned InN Nanorods by Metal-Organic Vapor Phase Epitaxy.

    PubMed

    Tessarek, C; Fladischer, S; Dieker, C; Sarau, G; Hoffmann, B; Bashouti, M; Göbelt, M; Heilmann, M; Latzel, M; Butzen, E; Figge, S; Gust, A; Höflich, K; Feichtner, T; Büchele, M; Schwarzburg, K; Spiecker, E; Christiansen, S

    2016-06-08

    Vertically aligned hexagonal InN nanorods were grown mask-free by conventional metal-organic vapor phase epitaxy without any foreign catalyst. The In droplets on top of the nanorods indicate a self-catalytic vapor-liquid-solid growth mode. A systematic study on important growth parameters has been carried out for the optimization of nanorod morphology. The nanorod N-polarity, induced by high temperature nitridation of the sapphire substrate, is necessary to achieve vertical growth. Hydrogen, usually inapplicable during InN growth due to formation of metallic indium, and silane are needed to enhance the aspect ratio and to reduce parasitic deposition beside the nanorods on the sapphire surface. The results reveal many similarities between InN and GaN nanorod growth showing that the process despite the large difference in growth temperature is similar. Transmission electron microscopy, spatially resolved energy-dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy have been performed to analyze the structural properties. Spatially resolved cathodoluminescence investigations are carried out to verify the optical activity of the InN nanorods. The InN nanorods are expected to be the material of choice for high-efficiency hot carrier solar cells.

  10. Adsorption of gas molecules on graphene-like InN monolayer: A first-principle study

    NASA Astrophysics Data System (ADS)

    Sun, Xiang; Yang, Qun; Meng, Ruishen; Tan, Chunjian; Liang, Qiuhua; Jiang, Junke; Ye, Huaiyu; Chen, Xianping

    2017-05-01

    Using first-principles calculation within density functional theory (DFT), we study the gas (CO, NH3, H2S, NO2, NO, SO2) adsorption properties on the surface of single-layer indium nitride (InN). Four different adsorption sites (Bridge, In, N, Hollow) are chosen to explore the most sensitive adsorption site. On the basis of the adsorption energy, band gap and charge transfer, we find that the most energetic favourable site is changeable between In site and N site for different gases. Moreover, our results reveal that InN is sensitive to NH3, SO2, H2S and NO2, by a physisorption or a chemisorption nature. We also perform a perpendicular electric field to the system and find that the applied electric field has a significant effect for the adsorption process. Besides, we also observed the desorption effects on NH3 adsorbed at the hollow site of InN when the electric field applied. In addition, the optical properties of InN monolayer affected by different gases are also discussed. Most of the gas adsorptions will cause the inhibition of light adsorption while the others can reduce the work function or enhance the adsorption ability in visible region. Our theoretical results indicate that monolayer InN is a promising candidate for gas sensing applications.

  11. Chemical nature of silicon nitride-indium phosphide interface and rapid thermal annealing for InP MISFETs

    NASA Technical Reports Server (NTRS)

    Biedenbender, M. D.; Kapoor, V. J.

    1990-01-01

    A rapid thermal annealing (RTA) process in pure N2 or pure H2 was developed for ion-implanted and encapsulated indium phosphide compound semiconductors, and the chemical nature at the silicon nitride-InP interface before and after RTA was examined using XPS. Results obtained from SIMS on the atomic concentration profiles of the implanted silicon in InP before and after RTA are presented, together with electrical characteristics of the annealed implants. Using the RTA process developed, InP metal-insulator semiconductor FETs (MISFETS) were fabricated. The MISFETS prepared had threshold voltages of +1 V, transconductance of 27 mS/mm, peak channel mobility of 1200 sq cm/V per sec, and drain current drift of only 7 percent.

  12. Chemical nature of silicon nitride-indium phosphide interface and rapid thermal annealing for InP MISFETs

    NASA Technical Reports Server (NTRS)

    Biedenbender, M. D.; Kapoor, V. J.

    1990-01-01

    A rapid thermal annealing (RTA) process in pure N2 or pure H2 was developed for ion-implanted and encapsulated indium phosphide compound semiconductors, and the chemical nature at the silicon nitride-InP interface before and after RTA was examined using XPS. Results obtained from SIMS on the atomic concentration profiles of the implanted silicon in InP before and after RTA are presented, together with electrical characteristics of the annealed implants. Using the RTA process developed, InP metal-insulator semiconductor FETs (MISFETS) were fabricated. The MISFETS prepared had threshold voltages of +1 V, transconductance of 27 mS/mm, peak channel mobility of 1200 sq cm/V per sec, and drain current drift of only 7 percent.

  13. First stages of the InP(1 0 0) surfaces nitridation studied by AES, EELS and EPES

    NASA Astrophysics Data System (ADS)

    Petit, M.; Ould-Metidji, Y.; Robert, Ch.; Bideux, L.; Gruzza, B.; Matolin, V.

    2003-05-01

    The nitrides of group III metals: AlN, GaN and InN are very important materials due to their applications for short wavelength opto-electronics (light-emitting diodes and laser diodes). It is essential for the realization of such novel devices to grow high-quality nitride single crystals. In this paper, we report the first stages of the InP(1 0 0) surfaces nitridation in order to grow high-quality nitride films. Indeed, the nitridation process is an important step in the growth of nitrides [J. Vac. Sci. Technol. A 17 (1999) 2194; Phys. Status Solidi A 176 (1999) 595]. Previous works [Synth. Met. 90 (1997) 2233; Appl. Phys. Lett. 63 (1993) 1957] have shown that in situ Ar + ions bombardment is useful on the one hand to clean the surface, and on the other hand to create droplets of metallic indium in well-controlled quantity. Then the indium metallic enrichment of the surface, monitoring by elastic peak electron spectroscopy (EPES) and Auger electron spectroscopy (AES) allows to prepare the III-V semiconductors surfaces to the nitridation step. The nitridated process has been performed with a high voltage plasma discharge cell and has been studied using quantitative Auger electron spectroscopy, elastic peak electron spectroscopy and electron energy loss spectroscopy (EELS), in order to optimize the conditions of InN layers formation.

  14. Electron transport and electron energy distributions within the wurtzite and zinc-blende phases of indium nitride: Response to the application of a constant and uniform electric field

    SciTech Connect

    Siddiqua, Poppy; Hadi, Walid A.; Salhotra, Amith K.; O'Leary, Stephen K.; Shur, Michael S.

    2015-03-28

    Within the framework of an ensemble semi-classical three-valley Monte Carlo electron transport simulation approach, we critically contrast the nature of the electron transport that occurs within the wurtzite and zinc-blende phases of indium nitride in response to the application of a constant and uniform electric field. We use the electron energy distribution and its relationship with the electron transport characteristics in order to pursue this analysis. For the case of zinc-blende indium nitride, only a peak corresponding to the electrons within the lowest energy conduction band valley is observed, this peak being seen to broaden and shift to higher energies in response to increases in the applied electric field strength, negligible amounts of upper energy conduction band valley occupancy being observed. In contrast, for the case of wurtzite indium nitride, in addition to the aforementioned lowest energy conduction band valley peak in the electron energy distribution, and its broadening and shifting to higher energies in response to increases in the applied electric field strength, beyond a certain critical electric field strength, 30 kV/cm for the case of this particular material, upper energy conduction band valley occupancy is observed, this occupancy being further enhanced in response to further increases in the applied electric field strength. Reasons for these results are provided. The potential for device consequences is then commented upon.

  15. Indium gallium nitride-based ultraviolet, blue, and green light-emitting diodes functionalized with shallow periodic hole patterns.

    PubMed

    Jeong, Hyun; Salas-Montiel, Rafael; Lerondel, Gilles; Jeong, Mun Seok

    2017-04-04

    In this study, we investigated the improvement in the light output power of indium gallium nitride (InGaN)-based ultraviolet (UV), blue, and green light-emitting diodes (LEDs) by fabricating shallow periodic hole patterns (PHPs) on the LED surface through laser interference lithography and inductively coupled plasma etching. Noticeably, different enhancements were observed in the light output powers of the UV, blue, and green LEDs with negligible changes in the electrical properties in the light output power versus current and current versus voltage curves. In addition, confocal scanning electroluminescence microscopy is employed to verify the correlation between the enhancement in the light output power of the LEDs with PHPs and carrier localization of InGaN/GaN multiple quantum wells. Light propagation through the PHPs on the UV, blue, and green LEDs is simulated using a three-dimensional finite-difference time-domain method to confirm the experimental results. Finally, we suggest optimal conditions of PHPs for improving the light output power of InGaN LEDs based on the experimental and theoretical results.

  16. Indium gallium nitride-based ultraviolet, blue, and green light-emitting diodes functionalized with shallow periodic hole patterns

    NASA Astrophysics Data System (ADS)

    Jeong, Hyun; Salas-Montiel, Rafael; Lerondel, Gilles; Jeong, Mun Seok

    2017-04-01

    In this study, we investigated the improvement in the light output power of indium gallium nitride (InGaN)-based ultraviolet (UV), blue, and green light-emitting diodes (LEDs) by fabricating shallow periodic hole patterns (PHPs) on the LED surface through laser interference lithography and inductively coupled plasma etching. Noticeably, different enhancements were observed in the light output powers of the UV, blue, and green LEDs with negligible changes in the electrical properties in the light output power versus current and current versus voltage curves. In addition, confocal scanning electroluminescence microscopy is employed to verify the correlation between the enhancement in the light output power of the LEDs with PHPs and carrier localization of InGaN/GaN multiple quantum wells. Light propagation through the PHPs on the UV, blue, and green LEDs is simulated using a three-dimensional finite-difference time-domain method to confirm the experimental results. Finally, we suggest optimal conditions of PHPs for improving the light output power of InGaN LEDs based on the experimental and theoretical results.

  17. Indium gallium nitride-based ultraviolet, blue, and green light-emitting diodes functionalized with shallow periodic hole patterns

    PubMed Central

    Jeong, Hyun; Salas-Montiel, Rafael; Lerondel, Gilles; Jeong, Mun Seok

    2017-01-01

    In this study, we investigated the improvement in the light output power of indium gallium nitride (InGaN)-based ultraviolet (UV), blue, and green light-emitting diodes (LEDs) by fabricating shallow periodic hole patterns (PHPs) on the LED surface through laser interference lithography and inductively coupled plasma etching. Noticeably, different enhancements were observed in the light output powers of the UV, blue, and green LEDs with negligible changes in the electrical properties in the light output power versus current and current versus voltage curves. In addition, confocal scanning electroluminescence microscopy is employed to verify the correlation between the enhancement in the light output power of the LEDs with PHPs and carrier localization of InGaN/GaN multiple quantum wells. Light propagation through the PHPs on the UV, blue, and green LEDs is simulated using a three-dimensional finite-difference time-domain method to confirm the experimental results. Finally, we suggest optimal conditions of PHPs for improving the light output power of InGaN LEDs based on the experimental and theoretical results. PMID:28374856

  18. Synthesis of aluminium indium nitride (AlInN) thin films by stacked elemental layers method

    NASA Astrophysics Data System (ADS)

    Afzal, Naveed; Devarajan, Mutharasu; Ibrahim, Kamarulazizi

    2014-07-01

    AlInN thin films were synthesized on Si substrates by using stacked elemental layers (SEL) technique. Three stacking sequence Al/InN, Al/InN/Al/InN and Al/InN/Al/InN/Al/InN were prepared on Si (1 0 0) substrates by reactive RF sputtering of In target in Ar-N2 and DC sputtering of Al target in Ar atmosphere at room temperature. Annealing of the deposited stacks was carried out at 400 °C for 6 h in a three zone tube furnace. Structural properties of the annealed films were investigated using X-ray diffraction (XRD) whereas the surface analysis of the films was carried out using field emission scanning electron microscope (FESEM) and atomic force microscope (AFM). XRD results show the formation of wurtzite AlInN thin films which become more obvious with increasing the stacked layers. FESEM analysis reveals drops-like polycrystalline films structure with randomly oriented grains whereas the AFM results show a decrease in the surface roughness with increasing stacking sequence. The formation of more prominent AlInN films with increase of stacking layers is attributed to a uniform interaction among the top and bottom Al and InN multilayers as a result of the annealing.

  19. Theoretical Study of Indium Compounds of Interest for Organometallic Chemical Vapor Deposition

    NASA Technical Reports Server (NTRS)

    Cardelino, B. H.; Moore, C. E.; Cardelino, C. A.; Frazier, D. O.; Backmann, K. J.

    2000-01-01

    The structural. electronic and therinochemical properties of indium compounds which are of interest in halide transport and organometallic chemical vapor deposition processes have been studied by ab initio and statistical mechanics methods. The compounds reported include: indium halides and hydrides (InF, InCl, InCl3, InH, InH2, InH3); indium clusters (In2, In3); methylindium, dimethylindium, and their hydrogen derivatives [In(CH3), In(CH3)H, In(CH3)H2, In(CH3)2, In(CH3)2H]; dimethyl-indium dimer [In2(CH3)4], trimethyl-indium [In(CH3)3]; dehydrogenated methyl, dimethyl and trimethylindium [In(CH3)2CH2, In(CH3)CH2, In(CH2)], trimethylindium adducts with ammonia, trimethylamine and hydrazine [(CH3)3In:NH3, (CH3)3In:N(CH3)3, (CH3)3In:N(H2)N(H2)]; dimethylamino-indium and methylimino-indium [In(CH3)2(NH2), In(CH3)(NH)]; indium nitride and indium nitride dimer (InN, In2N2), indium phosphide, arsenide and antimonide ([InP, InAs, InSb). The predicted electronic properties are based on density functional theory calculations; the calculated thermodynamic properties are reported following the format of the JANAF (Joint Army, Navy, NASA, Air Force) Tables. Equilibrium compositions at two temperatures (298 and 1000 K) have been analyzed for groups of competing simultaneous reactions.

  20. Theoretical Study of Indium Compounds of Interest for Organometallic Chemical Vapor Deposition

    NASA Technical Reports Server (NTRS)

    Cardelino, B. H.; Moore, C. E.; Cardelino, C. A.; Frazier, D. O.; Backmann, K. J.

    2000-01-01

    The structural. electronic and therinochemical properties of indium compounds which are of interest in halide transport and organometallic chemical vapor deposition processes have been studied by ab initio and statistical mechanics methods. The compounds reported include: indium halides and hydrides (InF, InCl, InCl3, InH, InH2, InH3); indium clusters (In2, In3); methylindium, dimethylindium, and their hydrogen derivatives [In(CH3), In(CH3)H, In(CH3)H2, In(CH3)2, In(CH3)2H]; dimethyl-indium dimer [In2(CH3)4], trimethyl-indium [In(CH3)3]; dehydrogenated methyl, dimethyl and trimethylindium [In(CH3)2CH2, In(CH3)CH2, In(CH2)], trimethylindium adducts with ammonia, trimethylamine and hydrazine [(CH3)3In:NH3, (CH3)3In:N(CH3)3, (CH3)3In:N(H2)N(H2)]; dimethylamino-indium and methylimino-indium [In(CH3)2(NH2), In(CH3)(NH)]; indium nitride and indium nitride dimer (InN, In2N2), indium phosphide, arsenide and antimonide ([InP, InAs, InSb). The predicted electronic properties are based on density functional theory calculations; the calculated thermodynamic properties are reported following the format of the JANAF (Joint Army, Navy, NASA, Air Force) Tables. Equilibrium compositions at two temperatures (298 and 1000 K) have been analyzed for groups of competing simultaneous reactions.

  1. Metal organic chemical vapor deposition of indium gallium nitride alloys on nanowire substrates

    NASA Astrophysics Data System (ADS)

    Pendyala, Chandrashekhar

    Rising environmental concerns due to our rising population and energy demand along with our excessive dependence on fossil fuels has created an urgent need to find clean, renewable and carbon free source of energy. Photoelectrochemical (PEC) water splitting is a clean and carbon free process where hydrogen is produced from water and sunlight using a semiconductor. To date, no material has been found that meets the stringent requirements of band gap, band edge positions and stability for spontaneous water splitting. It is however possible to use two materials to meet the criteria. In this regard, InGaN alloys with indium rich composition are interesting materials. However, very little is understood about the synthesis of thick (˜200--300 nm), single crystal InGaN layers for PEC applications. Heteroepitaxial growth of InGaN films on planar substrates induces phase segregation due to stress. Here, we proposed to investigate the role of nanowires as strain relaxing substrates to mitigate phase segregation. GaN nanowires with controlled orientation and small diameters were synthesized on various substrates by controlling the temperature and material flux to control the nuclei formation. The mechanism to control the growth mode using equilibrium solubility was validated with the III-Sb system. InGaN layers with controlled composition were synthesized on the GaN nanowires in a custom built MOCVD reactor. The InGaN layers are single crystalline, without any phase segregation. It was observed that only nanowires with diameters < 30 nm led to the observation while nanowires with larger diameters (˜ 100 nm) act as planar substrates resulting in polycrystalline growth. The heteroepitaxial growth was observed to evolve from initial InGaN islands coalescing into single crystalline shell on the GaN nanowires. Morphology of the InGaN shells was observed to depend on the orientation of the GaN nanowire substrates with c-GaN nanowires resulting in hexagonal shell while a

  2. Giant Reduction of InN Surface Electron Accumulation: Compensation of Surface Donors by Mg Dopants

    NASA Astrophysics Data System (ADS)

    Linhart, W. M.; Chai, J.; Morris, R. J. H.; Dowsett, M. G.; McConville, C. F.; Durbin, S. M.; Veal, T. D.

    2012-12-01

    Extreme electron accumulation with sheet density greater than 1013cm-2 is almost universally present at the surface of indium nitride (InN). Here, x-ray photoemission spectroscopy and secondary ion mass spectrometry are used to show that the surface Fermi level decreases as the Mg concentration increases, with the sheet electron density falling to below 108cm-2. Surface space-charge calculations indicate that the lowering of the surface Fermi level increases the density of unoccupied donor-type surface states and that these are largely compensated by Mg acceptors in the near-surface hole depletion region rather than by accumulated electrons. This is a significant step towards the realization of InN-based optoelectronic devices.

  3. Structural and electronic properties of InN epitaxial layer grown on c-plane sapphire by chemical vapor deposition technique

    SciTech Connect

    Barick, Barun Kumar Prasad, Nivedita; Saroj, Rajendra Kumar; Dhar, Subhabrata

    2016-09-15

    Growth of InN epilayers on c-plane sapphire substrate by chemical vapor deposition technique using pure indium metal and ammonia as precursors has been systematically explored. It has been found that [0001] oriented indium nitride epitaxial layers with smooth surface morphology can be grown on c-plane sapphire substrates by optimizing the growth conditions. Bandgap of the film is observed to be Burstein–Moss shifted likely to be due to high background electron concentration. It has been found that the concentration of this unintentional doping decreases with the increase in the growth temperature and the ammonia flux. Epitaxial quality on the other hand deteriorates as the growth temperature increases. Moreover, the morphology of the deposited layer has been found to change from flat top islands to faceted mounds as the flow rate of ammonia increases. This phenomenon is expected to be related to the difference in surface termination character at low and high ammonia flow rates.

  4. 15. LOOKING WEST TOWARD OLD FAITHFUL INN. THE INN'S NAMESAKE, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. LOOKING WEST TOWARD OLD FAITHFUL INN. THE INN'S NAMESAKE, OLD FAITHFUL GEYSER IS AT LEFT. - Old Faithful Inn, 900' northeast of Snowlodge & 1050' west of Old Faithful Lodge, Lake, Teton County, WY

  5. High-pressure lattice dynamics in wurtzite and rocksalt indium nitride investigated by means of Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Ibáñez, J.; Oliva, R.; Manjón, F. J.; Segura, A.; Yamaguchi, T.; Nanishi, Y.; Cuscó, R.; Artús, L.

    2013-09-01

    We present an experimental and theoretical lattice-dynamical study of InN at high hydrostatic pressures. We perform Raman scattering measurements on five InN epilayers, with different residual strain and free electron concentrations. The experimental results are analyzed in terms of ab initio lattice-dynamical calculations on both wurtzite InN (w-InN) and rocksalt InN (rs-InN) as a function of pressure. Experimental and theoretical pressure coefficients of the optical modes in w-InN are compared, and the role of residual strain on the measured pressure coefficients is analyzed. In the case of the LO band, we analyze and discuss its pressure behavior considering the double-resonance mechanism responsible for the selective excitation of LO phonons with large wave vectors in w-InN. The pressure behavior of the L- coupled mode observed in a heavily doped n-type sample allows us to estimate the pressure dependence of the electron effective mass in w-InN. The results thus obtained are in good agreement with k·p theory. The wurtzite-to-rocksalt phase transition on the upstroke cycle and the rocksalt-to-wurtzite backtransition on the downstroke cycle are investigated, and the Raman spectra of both phases are interpreted in terms of DFT lattice-dynamical calculations.

  6. Auger recombination as the dominant recombination process in indium nitride at low temperatures during steady-state photoluminescence

    SciTech Connect

    Seetoh, I. P.; Soh, C. B.; Fitzgerald, E. A.; Chua, S. J.

    2013-03-11

    Auger recombination in InN films grown by metal-organic chemical vapor deposition was studied by steady-state photoluminescence at different laser excitation powers and sample temperatures. It was dominant over radiative recombination and Shockley-Read-Hall recombination at low temperatures, contributing to the sub-linear relationship between the integrated photoluminescence intensity and laser excitation power. Auger recombination rates increased gradually with temperature with an activation energy of 10-17 meV, in good agreement with values from transient photoluminescence reported in literature. As the Auger recombination rates were independent of material quality, they may form an upper limit to the luminous efficiency of InN.

  7. Electronic and thermoelectric properties of InN studied using ab initio density functional theory and Boltzmann transport calculations

    SciTech Connect

    Borges, P. D. E-mail: lscolfaro@txstate.edu; Scolfaro, L. E-mail: lscolfaro@txstate.edu

    2014-12-14

    The thermoelectric properties of indium nitride in the most stable wurtzite phase (w-InN) as a function of electron and hole concentrations and temperature were studied by solving the semiclassical Boltzmann transport equations in conjunction with ab initio electronic structure calculations, within Density Functional Theory. Based on maximally localized Wannier function basis set and the ab initio band energies, results for the Seebeck coefficient are presented and compared with available experimental data for n-type as well as p-type systems. Also, theoretical results for electric conductivity and power factor are presented. Most cases showed good agreement between the calculated properties and experimental data for w-InN unintentionally and p-type doped with magnesium. Our predictions for temperature and concentration dependences of electrical conductivity and power factor revealed a promising use of InN for intermediate and high temperature thermoelectric applications. The rigid band approach and constant scattering time approximation were utilized in the calculations.

  8. Smooth e-beam-deposited tin-doped indium oxide for III-nitride vertical-cavity surface-emitting laser intracavity contacts

    NASA Astrophysics Data System (ADS)

    Leonard, J. T.; Cohen, D. A.; Yonkee, B. P.; Farrell, R. M.; DenBaars, S. P.; Speck, J. S.; Nakamura, S.

    2015-10-01

    We carried out a series of simulations analyzing the dependence of mirror reflectance, threshold current density, and differential efficiency on the scattering loss caused by the roughness of tin-doped indium oxide (ITO) intracavity contacts for 405 nm flip-chip III-nitride vertical-cavity surface-emitting lasers (VCSELs). From these results, we determined that the ITO root-mean-square (RMS) roughness should be <1 nm to minimize scattering losses in VCSELs. Motivated by this requirement, we investigated the surface morphology and optoelectronic properties of electron-beam (e-beam) evaporated ITO films, as a function of substrate temperature and oxygen flow and pressure. The transparency and conductivity were seen to increase with increasing temperature. Decreasing the oxygen flow and pressure resulted in an increase in the transparency and resistivity. Neither the temperature, nor oxygen flow and pressure series on single-layer ITO films resulted in highly transparent and conductive films with <1 nm RMS roughness. To achieve <1 nm RMS roughness with good optoelectronic properties, a multi-layer ITO film was developed, utilizing a two-step temperature scheme. The optimized multi-layer ITO films had an RMS roughness of <1 nm, along with a high transparency (˜90% at 405 nm) and low resistivity (˜2 × 10-4 Ω-cm). This multi-layer ITO e-beam deposition technique is expected to prevent p-GaN plasma damage, typically observed in sputtered ITO films on p-GaN, while simultaneously reducing the threshold current density and increasing the differential efficiency of III-nitride VCSELs.

  9. Effect of nitrogen doping on the structural, optical and electrical properties of indium tin oxide films prepared by magnetron sputtering for gallium nitride light emitting diodes

    NASA Astrophysics Data System (ADS)

    Tian, Lifei; Cheng, Guoan; Wang, Hougong; Wu, Yulong; Zheng, Ruiting; Ding, Peijun

    2017-01-01

    The indium tin oxide (ITO) films are prepared by the direct current magnetron sputtering technology with an ITO target in a mixture of argon and nitrogen gas at room temperature. The blue transmittance at 455 nm rises from 63% to 83% after nitrogen doping. The resistivity of the ITO film reduces from 4.6 × 10-3 (undoped film) to 5.7 × 10-4 Ω cm (N-doped film). The X-ray photoelectron spectroscopy data imply that the binding energy of the In3d5/2 peak is declined 0.05 eV after nitrogen doping. The high resolution transmission electron microscope images show that the nitrogen loss density of the GaN/ITO interface with N-doped ITO film is smaller than that of the GaN/ITO interface with undoped ITO film. The forward turn-on voltage of gallium nitride light emitting diode reduces by 0.5 V after nitrogen doping. The fabrication of the N-doped ITO film is conducive to modify the N component of the interface between GaN and ITO layer.

  10. Fabrication of conducting-filament-embedded indium tin oxide electrodes: application to lateral-type gallium nitride light-emitting diodes.

    PubMed

    Kim, Hee-Dong; Kim, Kyeong Heon; Kim, Su Jin; Kim, Tae Geun

    2015-11-02

    A novel conducting filament (CF)-embedded indium tin oxide (ITO) film is fabricated using an electrical breakdown method. To assess the performance of this layer as an ohmic contact, it is applied to GaN (gallium nitride) light-emitting diodes (LEDs) as a p-type electrode for comparison with typical GaN LEDs using metallic ITO. The operating voltage and output power of the LED with the CF embedded ITO are 3.93 V and 8.49 mW, respectively, at an injection current of 100 mA. This is comparable to the operating voltage and output power of the conventionally fabricated LEDs using metallic ITO (3.93 V and 8.43 mW). Moreover, the CF-ITO LED displays uniform and bright light emission indicating excellent current injection and spreading. These results suggest that the proposed method of forming ohmic contacts is at least as effective as the conventional method.

  11. InN Thin Film Lattice Dynamics by Grazing Incidence Inelastic X-Ray Scattering

    NASA Astrophysics Data System (ADS)

    Serrano, J.; Bosak, A.; Krisch, M.; Manjón, F. J.; Romero, A. H.; Garro, N.; Wang, X.; Yoshikawa, A.; Kuball, M.

    2011-05-01

    Achieving comprehensive information on thin film lattice dynamics so far has eluded well established spectroscopic techniques. We demonstrate here the novel application of grazing incidence inelastic x-ray scattering combined with ab initio calculations to determine the complete elastic stiffness tensor, the acoustic and low-energy optic phonon dispersion relations of thin wurtzite indium nitride films. Indium nitride is an especially relevant example, due to the technological interest for optoelectronic and solar cell applications in combination with other group III nitrides.

  12. Plasma-deposited germanium nitride gate insulators for indium phosphide metal-insulator-semiconductor field-effect transistors

    NASA Technical Reports Server (NTRS)

    Johnson, Gregory A.; Kapoor, Vik J.

    1991-01-01

    Plasma-deposited germanium nitride was investigated for the first time as a possible gate insulator for InP compound semiconductor metal-insulator-semiconductor FET (MISFET) technology. The germanium nitride films were successfully deposited in a capacitively coupled parallel plate reactor at 13.56 MHz operation using GeH4/N2/NH3 and GeH4/N2 mixtures as reactant gases. The former process produced better quality films with enhanced uniformity, increased deposition rates, and increased resistivity. The breakdown field strength of the films was greater than 10 to the 6th V/cm. Auger electron spectroscopy did not indicate significant chemical composition differences between the two processes. For MISFETs with 2-micron channel lengths fabricated on InP, the device transconductance and threshold voltage for the GeH4/N2/NH3 process were 17 mS/mm and -3.6 V, respectively. The drain-source breakdown voltages were greater than 10 V.

  13. Plasma-deposited germanium nitride gate insulators for indium phosphide metal-insulator-semiconductor field-effect transistors

    NASA Technical Reports Server (NTRS)

    Johnson, Gregory A.; Kapoor, Vik J.

    1991-01-01

    Plasma-deposited germanium nitride was investigated for the first time as a possible gate insulator for InP compound semiconductor metal-insulator-semiconductor FET (MISFET) technology. The germanium nitride films were successfully deposited in a capacitively coupled parallel plate reactor at 13.56 MHz operation using GeH4/N2/NH3 and GeH4/N2 mixtures as reactant gases. The former process produced better quality films with enhanced uniformity, increased deposition rates, and increased resistivity. The breakdown field strength of the films was greater than 10 to the 6th V/cm. Auger electron spectroscopy did not indicate significant chemical composition differences between the two processes. For MISFETs with 2-micron channel lengths fabricated on InP, the device transconductance and threshold voltage for the GeH4/N2/NH3 process were 17 mS/mm and -3.6 V, respectively. The drain-source breakdown voltages were greater than 10 V.

  14. InN Quantum Dot Based Infra-Red Photodetectors.

    PubMed

    Shetty, Arjun; Kumar, Mahesh; Roull, Basanta; Vinoy, K J; Krupanidhj, S B

    2016-01-01

    Self-assembled InN quantum dots (QDs) were grown on Si(111) substrate using plasma assisted molecular beam epitaxy (PA-MBE). Single-crystalline wurtzite structure of InN QDs was confirmed by X-ray diffraction. The dot densities were varied by varying the indium flux. Variation of dot density was confirmed by FESEM images. Interdigitated electrodes were fabricated using standard lithog- raphy steps to form metal-semiconductor-metal (MSM) photodetector devices. The devices show strong infrared response. It was found that the samples with higher density of InN QDs showed lower dark current and higher photo current. An explanation was provided for the observations and the experimental results were validated using Silvaco Atlas device simulator.

  15. Experimental and Theoretical Analysis of Strain Engineered Aluminium Nitride on Silicon for High Quality Aluminium(x)Indium(y)Gallium(1-x-y)Nitride Epitaxy

    NASA Astrophysics Data System (ADS)

    Tungare, Mihir

    III-Nitrides on Si are of great technological importance due to the availability of large area, epi ready Si substrates and the ability to heterointegrate with mature silicon micro and nanoelectronics. The major roadblock with realizing this is the large difference in thermal expansion coefficients and lattice constants between the two material systems. A novel technique developed in our research lab shows the potential of simultaneous and substantial reduction in dislocation and crack density in GaN on Si (111). Research undertaken in the current doctoral dissertation, validates the superior GaN quality on Si obtained using our technique and determines the factors responsible for its successful implementation. Detailed study of the stress evolution and dislocation reduction mechanism within overgrown GaN on as-grown and engineered AlN/Si substrates is carried out. Based on the conclusions obtained in this study, a pulsed metal-organic chemical vapor deposition (MOCVD) technique for the growth of AlN on Si (111) is developed to achieve a smoother AlN buffer with larger islands. A 14× reduction in surface pit density for overgrown GaN is attained on these AlN/Si substrates after substrate engineering. Deep green emission at 560 nm from InGaN/GaN MQWs with 10× increase in photoluminescence (PL) intensity is obtained on these templates. Molecular dynamics (MD) is used with an ultimate goal to theoretically understand the stress dilution mechanism and assist in improving the technique experimentally. Plausible models to accurately simulate wurtzite AlN (w-AlN) and AlN on Si (111) are developed. Motion of Si islands on Si (111) bulk substrate is examined to assess the required simulation conditions, their compliance with experimental set-up, and the limitations. Homoepitaxial growth of w-AlN is carried out to simulate epitaxial deposition as a starting point for heteroepitaxy of AlN on Si (111) and also to eventually build the entire complex film stack that closely

  16. High-Resolution Group III Nitride Microdisplays

    DTIC Science & Technology

    2011-12-14

    emissive displays based on gallium nitride micro-size LEDs may be suitable for ultra-portable products such as next- generation handheld projectors...semiconductors. Such devices would benefit from the outstanding physical properties of III- nitrides such as gallium nitride (GaN) and indium gallium ...projected image of a leopard from a green video graphics array indium gallium nitride (InGaN) microdisplay (640 480 pixels, each 12m in size with 15m

  17. Polarity and microstructure in InN thin layers grown by MOVPE

    NASA Astrophysics Data System (ADS)

    Kuwano, N.; Nakahara, Y.; Amano, H.

    2006-06-01

    Microstructures in InN grown on sapphire (0001) and yttria-stabilized zirconia (YSZ) (111) by metal-organic vapor phase epitaxy (MOVPE) were analyzed by means of transmission electron microscopy (TEM) in order to clarify the growth process. Special attention was paid to the selectivity of the crystal polarity of InN. The InN thin films grown on sapphire after nitridation has a flat surface while those grown on YSZ has hillocks on the surface. The crystal polarity was determined by comparing the experimentally observed intensity distribution in convergent beam electron diffraction (CBED) disks with those simulated by the Broch-wave method. It was found that the InN grown on the sapphire has a nitrogen-polarity and the one on YSZ has a mixture of In- and N-polarities. The effect of surface-nitridation of sapphire on the growth process is also discussed

  18. First principles calculations of structural, electronic and optical properties of InN compound

    NASA Astrophysics Data System (ADS)

    Graine, R.; Chemam, R.; Gasmi, F. Z.; Nouri, R.; Meradji, H.; Khenata, R.

    2015-11-01

    We carried out ab initio calculations of structural, electronic and optical properties of Indium nitride (InN) compound in both zinc blende and wurtzite phases, using the full-potential linearized augmented plane wave method (FP-LAPW), within the framework of density functional theory (DFT). For the exchange and correlation potential, local density approximation (LDA) and generalized gradient approximation (GGA) were used. Moreover, the alternative form of GGA proposed by Engel and Vosko (EV-GGA) and modified Becke-Johnson schemes (mBJ) were also applied for band structure calculations. Ground state properties such as lattice parameter, bulk modulus and its pressure derivative are calculated. Results obtained for band structure of these compounds have been compared with experimental results as well as other first principle computations. Our results show good agreement with the available data. The calculated band structure shows a direct band gap Γ → Γ. In the optical properties section, several optical quantities are investigated; in particular we have deduced the interband transitions from the imaginary part of the dielectric function.

  19. Two-dimensional electron gas in monolayer InN quantum wells

    SciTech Connect

    Pan, W. E-mail: e.dimakis@hzdr.de; Wang, G. T.; Dimakis, E. E-mail: e.dimakis@hzdr.de; Moustakas, T. D.; Tsui, D. C.

    2014-11-24

    We report in this letter experimental results that confirm the two-dimensional nature of the electron systems in a superlattice structure of 40 InN quantum wells consisting of one monolayer of InN embedded between 10 nm GaN barriers. The electron density and mobility of the two-dimensional electron system (2DES) in these InN quantum wells are 5 × 10{sup 15 }cm{sup −2} (or 1.25 × 10{sup 14 }cm{sup −2} per InN quantum well, assuming all the quantum wells are connected by diffused indium contacts) and 420 cm{sup 2}/Vs, respectively. Moreover, the diagonal resistance of the 2DES shows virtually no temperature dependence in a wide temperature range, indicating the topological nature of the 2DES.

  20. Growth mechanism and microstructure of low defect density InN (0001) In-face thin films on Si (111) substrates

    SciTech Connect

    Kehagias, Th.; Dimitrakopulos, G. P.; Koukoula, T.; Komninou, Ph.; Ajagunna, A. O.; Georgakilas, A.; Tsagaraki, K.; Adikimenakis, A.

    2013-10-28

    Transmission electron microscopy has been employed to analyze the direct nucleation and growth, by plasma-assisted molecular beam epitaxy, of high quality InN (0001) In-face thin films on (111) Si substrates. Critical steps of the heteroepitaxial growth process are InN nucleation at low substrate temperature under excessively high N-flux conditions and subsequent growth of the main InN epilayer at the optimum conditions, namely, substrate temperature 400–450 °C and In/N flux ratio close to 1. InN nucleation occurs in the form of a very high density of three dimensional (3D) islands, which coalesce very fast into a low surface roughness InN film. The reduced reactivity of Si at low temperature and its fast coverage by InN limit the amount of unintentional Si nitridation by the excessively high nitrogen flux and good bonding/adhesion of the InN film directly on the Si substrate is achieved. The subsequent overgrowth of the main InN epilayer, in a layer-by-layer growth mode that enhances the lateral growth of InN, reduces significantly the crystal mosaicity and the density of threading dislocations is about an order of magnitude less compared to InN films grown using an AlN/GaN intermediate nucleation/buffer layer on Si. The InN films exhibit the In-face polarity and very smooth atomically stepped surfaces.

  1. Accommodation mechanism of InN nanocolumns grown on Si(111) substrates by molecular beam epitaxy

    SciTech Connect

    Grandal, J.; Sanchez-Garcia, M. A.; Calleja, E.; Luna, E.; Trampert, A.

    2007-07-09

    High quality InN nanocolumns have been grown by molecular beam epitaxy on bare and AlN-buffered Si(111) substrates. The accommodation mechanism of the InN nanocolumns to the substrate was studied by transmission electron microscopy. Samples grown on AlN-buffered Si(111) show abrupt interfaces between the nanocolumns and the buffer layer, where an array of periodically spaced misfit dislocations develops. Samples grown on bare Si(111) exhibit a thin Si{sub x}N{sub y} at the InN nanocolumn/substrate interface because of Si nitridation. The Si{sub x}N{sub y} thickness and roughness may affect the nanocolumn relative alignment to the substrate. In all cases, InN nanocolumns grow strain- and defect-free.

  2. Growth of InN nanorods prepared by plasma-assisted molecular beam epitaxy with varying Cr thicknesses

    NASA Astrophysics Data System (ADS)

    Liu, K. W.; Young, S. J.; Chang, S. J.; Hsueh, T. H.; Chen, Y. Z.; Chen, K. J.; Hung, H.; Wang, S. M.; Wu, Y. L.

    2012-05-01

    This study investigates how the thickness of Cr deposited on the Si substrate after the nitridation process influences the AIN buffer layer and the InN nanorods. Atomic force microscopy results reveal that different thicknesses of Cr form varying sizes of CrN nanoislands. The results of scanning electron microscopy and X-ray diffraction show that a Cr deposition thickness of 10 nm results in CrN nanoislands after the nitridation process, improving the quality and density of InN nanorods. A Cr layer that was too thick led to polycrystalline InN growth. The results of transmission electron microscopy indicate a baseball bat-like InN nanorod growth mechanism.

  3. Growth of InN Nanowires with Uniform Diameter on Si(111) Substrates: Competition Between Migration and Desorption of In Atoms.

    PubMed

    Gao, Fangliang; Wen, Lei; Xu, Zhenzhu; Han, Jinglei; Yu, Yuefeng; Zhang, Shuguang; Li, Guoqiang

    2017-04-06

    The effects of the growth parameters on the uniformity and the aspect ratio of InN nanowires grown on Si(111) substrates have been studied systematically, and a modified quasi-equilibrium model is proposed. The growth temperature is of great importance for both the nucleation of the nanowires and the migration of In and N atoms, thus affecting the uniformity of the InN nanowires. In order to improve the uniformity of the InN nanowires, both traditional substrate nitridation and pre-In-droplet deposition have been implemented. It is found that the substrate nitridation is favorable for the nucleation of InN nanowires. However, the initial In atoms adhered to the substrate are insufficient to sustain the uniform growth of the InN nanowires. We have found that the initial In droplet on the substrate is not only advantageous for the nucleation of the InN nanowire, but also favorable for the In atom equilibrium between the initial In droplets and the direct In flux. Therefore, InN nanowires with a uniform aspect ratio and optimal diameter can be achieved. The results reported herein provide meaningful insights to understanding the growth kinetics during the InN nanowires growth, and open up great possibilities of developing high-performance group III-nitride-based devices.

  4. Fabrication of Si/InGaN Heterojunction Solar Cells by RF Sputtering Method: Improved Electrical and Optical Properties of Indium Gallium Nitride (InGaN) Thin Films

    NASA Astrophysics Data System (ADS)

    Jakkala, Pratheesh Kumar

    This dissertation presents a study on the fabrication of Indium Gallium Nitride (InGaN) based heterojunction solar cells using RF magnetron sputtering method. The goal of the study includes improving the electrical, optical and structural properties of InGaN thin films and examining their potential for photovoltaic applications and to reduce the parasitic resistive loses in solar cells. Reactive radio-frequency (RF) magnetron and Direct Current (DC) sputtering are deposition methods for thin films. The characterization techniques include Hall Effect measurement system for electrical properties, UV-Visible Spectroscopy for optical properties, X-Ray Diffraction (XRD) and Energy Dispersive X-Ray Spectroscopy (EDXS) for structural properties and AM 1.5 G irradiance spectrum to measure current-voltage (IV curves) and photovoltaic measurements. Copper Oxide thin films and Beryllium Zinc Oxide thin films are fabricated and their properties are examined for their potential to pair with n-InGaN to form a p-n junction. We conclude Silicon (111) wafer has better electrical properties than RF deposited Copper oxide and BeZnO and used as p-type layer. Aluminum (Al) and Indium Tin Oxide (ITO) are used as back and front metallic contacts respectively. In this study, we present a simple method for optical bandgap tuning of Indium Gallium Nitride (InGaN) thin films by controlling the growth conditions in magnetron RF sputtering. Thin films with different Indium (In) atomic compositions, x = 0.02 to 0.57 are deposited on high temperature aluminosilicate glass and Silicon (111) substrates. Substrate temperature is varied from 35 °C to 450 °C. Total pressure of sputtering gas mixture is kept constant at 12 mTorr but partial pressures of Ar and N2 are varied. Ar partial pressure to total pressure ratio is varied from 0 to 0.75. Optical bandgap values from 1.4 eV to 3.15 eV, absorption coefficient values of ˜ 10 4 /cm to ˜ 7 x 105 /cm and critical film thickness values of 0.04 mum

  5. III-Nitride nanowire optoelectronics

    NASA Astrophysics Data System (ADS)

    Zhao, Songrui; Nguyen, Hieu P. T.; Kibria, Md. G.; Mi, Zetian

    2015-11-01

    Group-III nitride nanowire structures, including GaN, InN, AlN and their alloys, have been intensively studied in the past decade. Unique to this material system is that its energy bandgap can be tuned from the deep ultraviolet (~6.2 eV for AlN) to the near infrared (~0.65 eV for InN). In this article, we provide an overview on the recent progress made in III-nitride nanowire optoelectronic devices, including light emitting diodes, lasers, photodetectors, single photon sources, intraband devices, solar cells, and artificial photosynthesis. The present challenges and future prospects of III-nitride nanowire optoelectronic devices are also discussed.

  6. Stopping Power Of He, C And O In InN

    SciTech Connect

    Barradas, N. P.; Alves, E.; Siketic, Z.; Radovic, I. Bogdanovic

    2011-06-01

    Group III nitrides such as InN, GaN, and their alloys are increasingly important in a host of optoelectronic and electronic devices. The presence of unintentional impurities is one of the factors that can strongly affect the electronic properties of these materials, and thus ion beam analysis techniques can play a fundamental role, in particular heavy ion elastic recoil detection analysis tracing and quantifying these contaminations. However, stopping powers in InN and GaN have not yet been measured, and data analysis relies on using the Bragg rule, which is often inaccurate. We have used a bulk method, previously developed by us and applied successfully to other systems, to determine experimentally the stopping power of several ions in InN. The results of our measurements and bulk method analysis are presented.

  7. BN, AlN, GaN, InN: Charge Neutrality Level, Surface, Interfaces, Doping

    NASA Astrophysics Data System (ADS)

    Brudnyi, V. N.

    2017-04-01

    On the basis of the charge neutrality concept, the analysis is fulfilled of the experimental data on the electron properties of the defective semiconductors after the radiation exposure, the electronic parameters of interfaces, surface work function and efficiency of doping with the impurities of high solubility in the nitrides of the group wz-III-N (BN, AlN, GaN, InN). The numerical evaluations of the charge neutrality levels in these compounds are presented.

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

    NASA Astrophysics Data System (ADS)

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

    2005-03-01

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

  9. Low-temperature self-limiting atomic layer deposition of wurtzite InN on Si(100)

    NASA Astrophysics Data System (ADS)

    Haider, Ali; Kizir, Seda; Biyikli, Necmi

    2016-04-01

    In this work, we report on self-limiting growth of InN thin films at substrate temperatures as low as 200 °C by hollow-cathode plasma-assisted atomic layer deposition (HCPA-ALD). The precursors used in growth experiments were trimethylindium (TMI) and N2 plasma. Process parameters including TMI pulse time, N2 plasma exposure time, purge time, and deposition temperature have been optimized for self-limiting growth of InN with in ALD window. With the increase in exposure time of N2 plasma from 40 s to 100 s at 200 °C, growth rate showed a significant decrease from 1.60 to 0.64 Å/cycle. At 200 °C, growth rate saturated as 0.64 Å/cycle for TMI dose starting from 0.07 s. Structural, optical, and morphological characterization of InN were carried out in detail. X-ray diffraction measurements revealed the hexagonal wurtzite crystalline structure of the grown InN films. Refractive index of the InN film deposited at 200 °C was found to be 2.66 at 650 nm. 48 nm-thick InN films exhibited relatively smooth surfaces with Rms surface roughness values of 0.98 nm, while the film density was extracted as 6.30 g/cm3. X-ray photoelectron spectroscopy (XPS) measurements depicted the peaks of indium, nitrogen, carbon, and oxygen on the film surface and quantitative information revealed that films are nearly stoichiometric with rather low impurity content. In3d and N1s high-resolution scans confirmed the presence of InN with peaks located at 443.5 and 396.8 eV, respectively. Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) further confirmed the polycrystalline structure of InN thin films and elemental mapping revealed uniform distribution of indium and nitrogen along the scanned area of the InN film. Spectral absorption measurements exhibited an optical band edge around 1.9 eV. Our findings demonstrate that HCPA-ALD might be a promising technique to grow crystalline wurtzite InN thin films at low substrate temperatures.

  10. Low-temperature self-limiting atomic layer deposition of wurtzite InN on Si(100)

    SciTech Connect

    Haider, Ali E-mail: biyikli@unam.bilkent.edu.tr; Kizir, Seda; Biyikli, Necmi E-mail: biyikli@unam.bilkent.edu.tr

    2016-04-15

    In this work, we report on self-limiting growth of InN thin films at substrate temperatures as low as 200 °C by hollow-cathode plasma-assisted atomic layer deposition (HCPA-ALD). The precursors used in growth experiments were trimethylindium (TMI) and N{sub 2} plasma. Process parameters including TMI pulse time, N{sub 2} plasma exposure time, purge time, and deposition temperature have been optimized for self-limiting growth of InN with in ALD window. With the increase in exposure time of N{sub 2} plasma from 40 s to 100 s at 200 °C, growth rate showed a significant decrease from 1.60 to 0.64 Å/cycle. At 200 °C, growth rate saturated as 0.64 Å/cycle for TMI dose starting from 0.07 s. Structural, optical, and morphological characterization of InN were carried out in detail. X-ray diffraction measurements revealed the hexagonal wurtzite crystalline structure of the grown InN films. Refractive index of the InN film deposited at 200 °C was found to be 2.66 at 650 nm. 48 nm-thick InN films exhibited relatively smooth surfaces with Rms surface roughness values of 0.98 nm, while the film density was extracted as 6.30 g/cm{sup 3}. X-ray photoelectron spectroscopy (XPS) measurements depicted the peaks of indium, nitrogen, carbon, and oxygen on the film surface and quantitative information revealed that films are nearly stoichiometric with rather low impurity content. In3d and N1s high-resolution scans confirmed the presence of InN with peaks located at 443.5 and 396.8 eV, respectively. Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) further confirmed the polycrystalline structure of InN thin films and elemental mapping revealed uniform distribution of indium and nitrogen along the scanned area of the InN film. Spectral absorption measurements exhibited an optical band edge around 1.9 eV. Our findings demonstrate that HCPA-ALD might be a promising technique to grow crystalline wurtzite InN thin films at low substrate

  11. Colloids in the River Inn

    NASA Astrophysics Data System (ADS)

    Ueckert, Martina; Niessner, Reinhard; Baumann, Thomas

    2015-04-01

    In the light of an increasing number of technical applications using nanoparticles and reports of adverse effects of engineered nanoparticles, research on the occurrence and stability of particles in all compartments has to be intensified. Colloids in river water represent the geologic setting, environmental conditions, and the anthropogenic use in its catchment. The river not only acts as a sink for nanoparticles but also as the source term due to exchange in the hyporheic zone and in bank filtration setups. The concentration, size distribution and elemental composition of particles in the River Inn were studied from the source in the Swiss Alps to the river mouth at Passau from 2008 to 2014. Samples were collected after each tributary from a sub-catchment and filtered on site using a new filtration device for gentle filtration. The elemental composition was determined after acid digestion with ICP/MS. SEM/EDX analysis provided morphological and elemental information for single particles. A complementary chemical analysis of the river water was performed to assess the geochemical stability of individual particles. As presented at EGU 2014, particles in the upper, rural parts mainly reveal changes in the geological setting of the tributary catchments. Not unexpectedly, particles originating from crystalline rocks, were more stable than particles originating from calcareous rocks. Anthropogenic and industrial influences increase in the lower parts. This went together with a change of the size distribution, an increase of the number of organic particles, and a decrease of the microfauna. Interestingly, specific leisure activities in a sub-catchment, like extensive downhill skiing, manifest itself in the particle composition. This general setting was validated in last year's sampling campaigns. An interesting change in on site parameters and hydrochemical composition was seen during all sampling campaigns at an inflow from the valley Kaunertal, Austria. Therefore

  12. Konocti Harbon Inn, Kelseyville, California

    SciTech Connect

    Not Available

    1982-04-01

    Konocti Harbor is a large resort complex, located on the shore of Clear Lake, in Kelseyville, California. A number of buildings on the property, including a 25,000 square foot lodge, 101 motel units and 48 apartment units are heated by the large water-to-water heat pumps, using water from the lake as a heat source. Due to low winter occupancy rates, these machines are run at very low capacity. In addition, a number of buildings are operated on electric resistance and propane backup boilers. This mode of operation results in a relatively high cost compared to the actual heating requirements. Since these systems were originally designed for low temperature water (125/sup 0/F supply 10/sup 0/..delta..t), a low temperature geothermal resource could potentially displace some of the conventional fuel currently used. The potential for geothermal use at the Konocti Harbor Inn is explored.

  13. An investigation into the conversion of In2O3 into InN nanowires

    NASA Astrophysics Data System (ADS)

    Papageorgiou, Polina; Zervos, Matthew; Othonos, Andreas

    2011-12-01

    Straight In2O3 nanowires (NWs) with diameters of 50 nm and lengths ≥2 μm have been grown on Si(001) via the wet oxidation of In at 850°C using Au as a catalyst. These exhibited clear peaks in the X-ray diffraction corresponding to the body centred cubic crystal structure of In2O3 while the photoluminescence (PL) spectrum at 300 K consisted of two broad peaks, centred around 400 and 550 nm. The post-growth nitridation of In2O3 NWs was systematically investigated by varying the nitridation temperature between 500 and 900°C, flow of NH3 and nitridation times between 1 and 6 h. The NWs are eliminated above 600°C while long nitridation times at 500 and 600°C did not result into the efficient conversion of In2O3 to InN. We find that the nitridation of In2O3 is effective by using NH3 and H2 or a two-step temperature nitridation process using just NH3 and slower ramp rates. We discuss the nitridation mechanism and its effect on the PL.

  14. Effect of interfacial lattice mismatch on bulk carrier concentration and band gap of InN

    SciTech Connect

    Kuyyalil, Jithesh; Tangi, Malleswararao; Shivaprasad, S. M.

    2012-10-15

    The issue of ambiguous values of the band gap (0.6 to 2 eV) of InN thin film in literature has been addressed by a careful experiment. We have grown wurtzite InN films by PA-MBE simultaneously on differently modified c-plane sapphire substrates and characterized by complementary structural and chemical probes. Our studies discount Mie resonances caused by metallic In segregation at grain boundaries as the reason for low band gap values ( Almost-Equal-To 0.6 eV) and also the formation of Indium oxides and oxynitrides as the cause for high band gap value ( Almost-Equal-To 2.0 eV). It is observed that polycrystallinity arising from azimuthal miss-orientation of c-oriented wurtzite InN crystals increases the carrier concentration and the band gap values. We have reviewed the band gap, carrier concentration, and effective mass of InN in literature and our own measurements, which show that the Moss-Burstein relation with a non-parabolic conduction band accounts for the observed variation of band gap with carrier concentration.

  15. MBE growth and processing of III/V-nitride semiconductor thin film structures: Growth of gallium indium arsenic nitride and nano-machining with focused ion beam and electron beam

    NASA Astrophysics Data System (ADS)

    Park, Yeonjoon

    The advanced semiconductor material InGaAsN was grown with nitrogen plasma assisted Molecular Beam Epitaxy (MBE). The InGaAsN layers were characterized with High Resolution X-ray Diffraction (HRXDF), Atomic Fore Microscope (AFM), X-ray Photoemission Spectroscopy (XPS) and Photo-Luminescence (PL). The reduction of the band gap energy was observed with the incorporation of nitrogen and the lattice matched condition to the GaAs substrate was achieved with the additional incorporation of indium. A detailed investigation was made for the growth mode changes from planar layer-by-layer growth to 3D faceted growth with a higher concentration of nitrogen. A new X-ray diffraction analysis was developed and applied to the MBE growth on GaAs(111)B, which is one of the facet planes of InGaAsN. As an effort to enhance the processing tools for advanced semiconductor materials, gas assisted Focused Ion Beam (FIB) vertical milling was performed on GaN. The FIB processed area shows an atomically flat surface, which is good enough for the fabrication of Double Bragg Reflector (DBR) mirrors for the Blue GaN Vertical Cavity Surface Emitting Laser (VCSEL) Diodes. An in-situ electron beam system was developed to combine the enhanced lithographic processing capability with the atomic layer growth capability by MBE. The electron beam system has a compensation capability against substrate vibration and thermal drift. In-situ electron beam lithography was performed with the low pressure assisting gas. The advanced processing and characterization methods developed in this thesis will assist the development of superior semiconductor materials for the future.

  16. Defect Doping of InN

    SciTech Connect

    Jones, R.E.; van Genuchten, H.C.M.; Yu, K.M.; Walukiewicz, W.; Li, S.X.; A ger III, J.W.; Liliental-Weber, Z.; Haller, E.E.; Lu, H.; Schaff, W.J.

    2007-07-22

    InN films grown by molecular beam epitaxy have been subjected to 2 MeV He{sup +} irradiation followed by thermal annealing. Theoretical analysis of the electron mobilities shows that thermal annealing removes triply charged donor defects, creating films with electron mobilities approaching those predicted for uncompensated, singly charged donors. Optimum thermal annealing of irradiated InN can be used to produce samples with electron mobilities higher than those of as grown films.

  17. Ab initio study of MOCVD synthesis of InN and GaN

    NASA Astrophysics Data System (ADS)

    Walkosz, Weronika; Zapol, Peter; Highland, Matthew J.; Fuoss, Paul H.; Stephenson, Gregory B.

    2011-03-01

    A detailed understanding of MOCVD growth of group III nitrides is important for improved control over their properties and performance in a wide range of applications. Because of the relative instability of InN, chemically active precursors such as NH3 are typically used to provide the high nitrogen activity needed for growth. Our goal is to understand the mechanism and species involved in active nitrogen formation on the growth surface. Here we present results of density functional theory calculations for the decomposition of NH3 on InN and GaN (0001) surfaces through reaction intermediates such as adsorbed NH2 and NH. The calculated equilibrium surface structures along with the reaction barriers for the dissociation pathways of NH3 on these surfaces are described. Kinetic modeling based on the calculated barriers to determine reaction mechanisms and effective nitrogen activities is discussed. The results will be used to elucidate chemical kinetics on GaN and InN (0001) surfaces under MOCVD growth conditions with the aim to optimize synthesis conditions and precursors for effective growth of metastable nitrides. Work supported by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-06CH11357.

  18. Colloids in the River Inn

    NASA Astrophysics Data System (ADS)

    Ueckert, Martina; Baumann, Thomas

    2014-05-01

    In the light of an increasing number of technical applications using nanoparticles and reports of adverse effects of engineered nanoparticles, research on the occurrence and stability of particles in all compartments has to be intensified. Colloids in river water represent the geologic setting, environmental conditions, and the anthropogenic use in its catchment. The river not only acts as a sink for nanoparticles but also as the source term due to exchange in the hyporheic zone and in bank filtration setups. The concentration, size distribution and elemental composition of particles in the River Inn were studied from the source in the Swiss Alps to the river mouth at Passau. Samples were collected after each tributary from a sub-catchment and filtered on-site. The elemental composition was determined after acid digestion with ICP/MS. SEM/EDX analyses provided morphological and elemental information for single particles. A complementary chemical analysis of the river water was performed to assess the geochemical stability of indvidual particles. Particles in the upper, rural parts mainly reveal changes in the geological setting of the tributary catchments. Not unexpectedly, particles originating from crystalline rocks, were more stable than particles originating from calcareous rocks. Anthropogenic and industrial influences increase in the lower parts. This went together with a change of the size distribution, an increase of the number of organic particles, and a decrease of the microfauna. Interestingly, specific leisure activities in a sub-catchment, like extensive downhill skiing, manifest itself in the particle composition.

  19. Molten salt-based growth of bulk GaN and InN for substrates.

    SciTech Connect

    Waldrip, Karen Elizabeth

    2007-08-01

    An atmospheric pressure approach to growth of bulk group III-nitrides is outlined. Native III-nitride substrates for optoelectronic and high power, high frequency electronics are desirable to enhance performance and reliability of these devices; currently, these materials are available in research quantities only for GaN, and are unavailable in the case of InN. The thermodynamics and kinetics of the reactions associated with traditional crystal growth techniques place these activities on the extreme edges of experimental physics. The novel techniques described herein rely on the production of the nitride precursor (N{sup 3-}) by chemical and/or electrochemical methods in a molten halide salt. This nitride ion is then reacted with group III metals in such a manner as to form the bulk nitride material. The work performed during the period of funding (February 2006-September 2006) focused on establishing that mass transport of GaN occurs in molten LiCl, the construction of a larger diameter electrochemical cell, the design, modification, and installation of a made-to-order glove box (required for handling very hygroscopic LiCl), and the feasibility of using room temperature molten salts to perform nitride chemistry experiments.

  20. The Children's Inn at NIH turns 25 | NIH MedlinePlus the Magazine

    MedlinePlus

    ... of this page please turn JavaScript on. Feature: The Children's Inn The Children's Inn at NIH turns 25 Past Issues / ... home …" for all families! What to Expect at The Children's Inn The Children's Inn enhances opportunities for ...

  1. Investigation of oxygen defects in wurtzite InN by using density functional theory

    NASA Astrophysics Data System (ADS)

    Hattori, Y.; Chubaci, J. F. D.; Matsuoka, M.; Freitas, J. A.; da Silva, A. Ferreira

    2016-12-01

    Density Functional Theory based on ab initio calculations was employed to investigate single and complex defects of oxygen in indium nitride and their influence on the optical properties. Different oxygen contents (x=1.38%, 4.16%, 5.55% and 11.11%) were considered in our study by using PBEsol-GGA and TB-mBJ for the treatment of exchange-correlation energy and potential. It was found that oxygen is energetically favorable to exist mainly as singly charged isolated defect. The results using TB-mBJ approximation predicts a narrowing of the VBM (valence band maximum) and CBM (conduction band minimum) as oxygen content increases. Nevertheless, the larger contribution of the Moss-Burstein effect leads to an effective band-gap increase, yielding absorption edge values larger than that of the intrinsic bulk indium nitride.

  2. Molten Salt-Based Growth of Bulk GaN and InN for Substrates

    SciTech Connect

    Waldrip, Karen Elizabeth; Tsao, Jeffrey Yeenien; Kerley, Thomas M.

    2006-09-01

    An atmospheric pressure approach to growth of bulk group III-nitrides is outlined. Native III-nitride substrates for optoelectronic and high power, high frequency electronics are desirable to enhance performance and reliability of these devices; currently, these materials are available in research quantities only for GaN, and are unavailable in the case of InN. The thermodynamics and kinetics of the reactions associated with traditional crystal growth techniques place these activities on the extreme edges of experimental physics. The technique described herein relies on the production of the nitride precursor (N3-) by chemical and/or electrochemical methods in a molten halide salt. This nitride ion is then reacted with group III metals in such a manner as to form the bulk nitride material. The work performed during the period of funding (July 2004-September 2005) focused on the initial measurement of the solubility of GaN in molten LiCl as a function of temperature, the construction of electrochemical cells, the modification of a commercial glove box (required for handling very hygroscopic LiCl), and on securing intellectual property for the technique.

  3. Novel compound semiconductor devices based on III-V nitrides

    SciTech Connect

    Pearton, S.J.; Abernathy, C.R.; Ren, F.

    1995-10-01

    New developments in dry and wet etching, ohmic contacts and epitaxial growth of Ill-V nitrides are reported. These make possible devices such as microdisk laser structures and GaAs/AlGaAs heterojunction bipolar transistors with improved InN ohmic contacts.

  4. Operational rules for the implementation of INN prescribing.

    PubMed

    Van Bever, Elien; Wirtz, Veronika J; Azermai, Majda; De Loof, Geert; Christiaens, Thierry; Nicolas, Luc; Van Bortel, Luc; Vander Stichele, Robert

    2014-01-01

    The aim is to describe the process, principles and results of the International Nonproprietary Name (INN) prescribing project in Belgium. The purpose of this project was to operationalize electronic INN prescribing for outpatient care in daily medical practice and to develop a factual database which can be used in electronic INN prescribing applications. The operationalization process consisted of three phases: (1) expert consultation, (2) review by regulatory authorities and (3) test phase with stakeholders and end-users. The INN prescribing project resulted into (1) operational rules for electronic INN prescribing and (2) a reference database to be implemented in commercial medical software. The operational rules for electronic INN prescribing define valid INN groups as sets of equivalent medicinal products, described by three elements: the therapeutic moiety (the active part of the therapeutic ingredient) or combination of therapeutic moieties, the strength (with standardized denominators), and the method of administration (with simplified but standardized options). The operational rules also define two categories of exemptions for INN prescribing: INN groups where the first choice of treatment should be continued throughout the therapy period (NO SWITCH) and medicinal product groups not suitable for INN prescribing (NO INN). The reference database is the result of the virtual classification of the Belgian therapeutic arsenal into INN groups, according to the operational rules. Defining the operational rules for INN prescribing for and with different stakeholders was a difficult yet feasible assignment. The INN prescribing project resulted into explicit operational rules and a reference database. The Belgian experience may provide important information for other countries planning to operationalize or refine electronic INN prescribing. It can also be used for a thorough evaluation of the impact of the new concept of INN prescribing on daily practice and on

  5. 2. Contextual view southwest from hillside behind Inn, with corner ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Contextual view southwest from hillside behind Inn, with corner of 'Big Sur Inn' Building (HABS-CA-2611-A) at extreme right, State Highway 1 curving through middle ground. - Deetjen's Big Sur Inn, Hayloft Building, East Side of State Highway 1, Big Sur, Monterey County, CA

  6. 3. View to southeast from hillside behind Inn. Roof of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. View to southeast from hillside behind Inn. Roof of 'Big Sur Inn' Building (HABS-CA-2611-A) at lower center, State Highway 1 bridge across Castro Creek Canyon at upper center. - Deetjen's Big Sur Inn, East Side of State Highway 1, Big Sur, Monterey County, CA

  7. 16. LOOKING WEST AT OLD FAITHFUL INN, MOST OF THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. LOOKING WEST AT OLD FAITHFUL INN, MOST OF THE EAST WING IS VISIBLE TO THE LEFT. THE EAST WING ADDITION WAS BUILT BY THE INN'S ORIGINAL ARCHITECT, ROBERT C. REAMER IN 1913-14. - Old Faithful Inn, 900' northeast of Snowlodge & 1050' west of Old Faithful Lodge, Lake, Teton County, WY

  8. Systematic Study of p-type Doping and Related Defects in III-Nitrides: Pathway toward a Nitride HBT

    DTIC Science & Technology

    2012-11-20

    16 Although beneficial for LEDs, lateral surface segregation of indium is detrimental for nitride solar cells and laser diodes , where recombination...1009 (2007). 44 S. D. Burnham, Improved Understanding and Control of Magnesium-Doped Gallium Nitride by Plasma Assisted Molecular Beam Epitaxy, in...mobility, and strong light absorption.1-3 Together these attributes make III- nitrides suited for light-emitting diodes (LEDs), high electron

  9. Taming transport in InN

    SciTech Connect

    Ager III, Joel W.; Miller, Nate R.

    2011-05-29

    The large electron affinity of InN, close to 6 eV and the largest of any III-V semiconductor, creates a strong driving force for native donor formation, both in the bulk and at surfaces and interfaces. Moreover, all InN surfaces, regardless of crystal orientation or doping, have been observed to have a surface accumulation layer of electrons, which interferes with standard electrical measurements. For these reasons, until recently, it was uncertain whether or not compensation by donor defects would prevent “real” p-type activity (i.e. existence of sufficiently shallow acceptors and mobile holes). A coordinated experimental approach using a combination of electrical (Hall effect) and electrothermal (Seebeck coefficient) measurements will be described that allows definitive evaluation of carrier transport in InN. In Mg-doped InN films, the sensitivity of thermopower to bulk hole conduction, combined with modeling of the parallel conducting layers (surface/bulk/interface), enables quantitative measurement of the free hole concentration and mobility. In undoped (n-type) material, combined Hall and thermopower measurements, along with a considering of the scattering mechanisms, leads to a quantitative understanding of the crucial role of charged line defects in limiting electron transport.

  10. Investigation of (In, Ga)N/GaN Quantum Structure for Nitride Lasers

    DTIC Science & Technology

    2012-02-01

    intended for photonic devices. 15. SUBJECT TERMS gallium nitride , quantum structures, lasers, light-emitting diodes 16. SECURITY CLASSIFICATION...distribution unlimited. 1.0 Executive Summary This is the final report for a project to experimentally and theoretically investigate indium gallium nitride ... gallium nitride ((In,Ga)N/GaN) quantum structures for future applications in light-emitting devices—specifically lasers. The nitride films were grown by

  11. Metalorganic vapor phase epitaxy of InN on GaN using tertiary-butylhydrazine as nitrogen source

    NASA Astrophysics Data System (ADS)

    Kremzow, Raimund; Pristovsek, Markus; Stellmach, Joachim; Savaş, Özgür; Kneissl, Michael

    2010-06-01

    The growth of InN on GaN/sapphire by metalorganic vapor-phase epitaxy (MOVPE) using tertiary-butylhydrazine (tBHy) was studied by varying temperature, V/III-ratio, growth time and carrier gas between nitrogen and hydrogen. The growth was characterized in-situ by spectroscopic ellipsometry and ex-situ by high resolution X-ray diffraction, atomic force microscopy and scanning electron microscopy. In contrast to ammonia, it was predicted that tBHy should allow InN growth for a much wider growth window and low V/III-ratios with growth temperatures below 600C. However, over a wide range of growth parameters only growth of metallic indium droplets was observed.

  12. Nitride light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Mukai, T.; Nagahama, S.; Iwasa, N.; Senoh, M.; Yamada, T.

    2001-08-01

    We review the progress in the field of InGaN-based light-emitting diodes (LEDs) and discuss the issue of threading dislocations and the luminous efficiency. The first candela-class blue LEDs have been developed. An InGaN layer was used to produce these LEDs instead of a GaN active layer. The quantum-well structure InGaN active layer dramatically improved the external quantum efficiency. There are a number of threading dislocations in nitride-based LEDs. InGaN LEDs, however, have quite high external quantum efficiency. With regard to this, it is thought that the fluctuation of the indium mole fraction is strongly related to the high external quantum efficiency. Considering the density of threading dislocations in the nitride-based LEDs, we discuss what can improve the external quantum efficiency of nitride-based LEDs.

  13. Rethinking the INN system for therapeutic antibodies

    PubMed Central

    Pottier, Jérémy; Chastang, Romane; Dumet, Christophe; Watier, Hervé

    2017-01-01

    ABSTRACT In the context of a possible revision of the International Nonproprietary Names (INN) system of recombinant monoclonal antibodies, which is saturated, we propose several avenues of reflection driven by the primary goal of the INN, information of health-care professionals. Clinical considerations argue for an abandon of the substems A (target category) and B (origin category), which lengthen the INN without real added-value. On the contrary, new substems or suffixes are required to alert on the absence/presence of an Fc portion and/or multispecificity, which are essential from a pharmacological point of view. Moreover, we think it necessary to explicitly mention Fc variations since they could influence the pharmacology of these biopharmaceuticals, and hence their efficacy and side-effects. Besides indicating the subclass/isotype in the documents easily accessible to health care professionals, we propose to systematically describe both the natural variations (allotypes) by using the Gm (G marker) system, and the artificial variations by using a Ge (G engineering) system that is discussed here and could apply to all IgG constant domains (tentatively called the Fy portion). PMID:27808597

  14. Mg doped InN and confirmation of free holes in InN

    SciTech Connect

    Wang, K.; Yamaguchi, T.; Miller, N.; Mayer, M. A.; Haller, E. E.; Iwamoto, R.; Araki, T.; Nanishi, Y.; Yu, K. M.; Walukiewicz, W.; Ager, J. W. III

    2011-01-24

    We report a systematic investigation on Mg doped InN epilayers grown by radio-frequency plasma-assisted molecular beam epitaxy. Electrolyte capacitance voltage (ECV) combined with thermopower measurements find p-type conduction over an Mg concentration range. For InN:Mg in this p-type 'window' the Seebeck coefficients dramatically change their signs from negative to positive when the thickness of undoped InN interlayer decreases to zero. This notable sign change of Seebeck coefficient explains the previous inconsistency between ECV and thermopower results and confirms the existence of mobile holes in the InN:Mg. Taking into account the undoped InN interlayer, the hole density and mobility are extracted.

  15. Post-growth thermal oxidation of wurtzite InN thin films into body-center cubic In{sub 2}O{sub 3} for chemical/gas sensing applications

    SciTech Connect

    Liu, H.F.; Yakovlev, N.L.; Chi, D.Z.; Liu, W.

    2014-06-01

    Post-growth thermal oxidations of InN have been studied using high-resolution x-ray diffraction (HRXRD) and secondary ion-mass spectroscopy (SIMS). The InN thin films, having relative high crystal quality, were grown by metal–organic chemical vapor deposition (MOCVD) on c-sapphire substrates using InGaN/GaN buffer layers. HRXRD reveals that oxidation of wurtzite InN into body-center cubic In{sub 2}O{sub 3} occurred at elevated temperatures. A Si{sub 3}N{sub 4} encapsulation improves the crystal quality of In{sub 2}O{sub 3} oxidized by using conventional rapid thermal annealing (RTA) but it results in the presence of undesired metallic indium. Cycle-RTA not only improves the crystal quality but also avoids the byproduct of metallic indium. SIMS depth profile, using contaminate elements as the ‘interface markers,’ provide evidence that the oxidation of InN is dominated by oxygen inward diffusion mechanism. Together with the HRXRD results, we conclude that the crystal quality of the resultant In{sub 2}O{sub 3}/InN heterostructure is mainly controlled by the balance between the speeds of oxygen diffusion and InN thermal dissociation, which can be effectively tuned by cycle-RTA. The obtained In{sub 2}O{sub 3}/InN heterostructures can be fundamental materials for studying high speed chemical/gas sensing devices. - Graphical abstract: Oxidation of h-InN into bcc-In{sub 2}O{sub 3} has been realized at elevated temperatures. A Si{sub 3}N{sub 4} cap improves the crystal quality of In{sub 2}O{sub 3} oxidized by conventional RTA but it results in the presence of undesired metallic indium. Cycle-RTA not only improves the crystal quality but also avoids the byproduct of metallic indium. SIMS depth profiles provide evidence that the oxidation of InN is dominated by oxygen inward diffusion mechanism. The crystal quality of the resultant In{sub 2}O{sub 3}/InN heterostructure is mainly controlled by the balance between the speeds of oxygen diffusion and InN thermal

  16. 1. View north from across State Highway 1 toward Inn. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. View north from across State Highway 1 toward Inn. 'Big Sur Inn' Building (HABS-CA-2611-A) visible at left, 'Hayloft' Building (HABS-CA-2611-B at right center, and 'Antique' Building (HABS-CA-2611-C) and 'Champagne' Building (HABS-CA-2611-D) out of sight behind trees at right. - Deetjen's Big Sur Inn, East Side of State Highway 1, Big Sur, Monterey County, CA

  17. Investigation of gas sensing properties of InN nanoparticles

    SciTech Connect

    Madapu, Kishore K. E-mail: dhara@igcar.gov.in; Prasad, A. K.; Tyagi, A. K.; Dhara, S. E-mail: dhara@igcar.gov.in

    2015-06-24

    InN nanoparticles were grown by chemical vapor deposition technique using In{sub 2}O{sub 3} as precursor material. Raman spectroscopic studies show the presence of the wurtzite phase of as-grown InN. Size of the nanoparticles were in range from quantum dot (<8 nm) to larger sized particles (100 nm). We studied the gas sensing properties of InN nanoparticles with CH{sub 4} gas. Sensors substrates were fabricated with interdigitated Au electrodes. InN nanoparticles show high response towards CH{sub 4} with minimum detectable concentration of 50 ppm at 200 °C.

  18. Enhanced Performance of Dye-Sensitized Solar Cells with Nanostructure InN Compact Layer

    NASA Astrophysics Data System (ADS)

    Chen, Cheng-Chiang; Chen, Lung-Chien; Kuo, Shu-Jung

    2013-05-01

    This study presents a dye-sensitized solar cells (DSSCs) with a nanostructured InN compact layer (InN-CPL). The effect of a nanostructured InN-CPL in a DSSC structure prepared by radio frequency magnetron sputtering was examined. The InN-CPL effectively reduces the back reaction at the interface between the indium tin oxide (ITO) transparent conductive film and the electrolyte in the DSSC. DSSCs fabricated on ITO/InN-CPL/TiO2/D719 exhibited a short-circuit current density (JSC), open-circuit voltage (VOC), and power conversion efficiency (η) of 23.2 mA/cm2, 0.7 V, and 8.9%, respectively.

  19. The Children's Inn at NIH Anniversary Key Messages | NIH MedlinePlus the Magazine

    MedlinePlus

    ... of this page please turn JavaScript on. Feature: The Children's Inn The Children's Inn at NIH Past Issues / Summer 2014 ... Contents Anniversary Key Messages Playground and Park at The Children's Inn at NIH. Photo courtesy of Mahan ...

  20. Growth kinetics and island evolution during double-pulsed molecular beam epitaxy of InN

    SciTech Connect

    Kraus, A.; Hein, C.; Bremers, H.; Rossow, U.; Hangleiter, A.

    2016-06-21

    The kinetic processes of InN growth using alternating source fluxes with sub-monolayer In pulses in plasma-assisted molecular beam epitaxy have been investigated. Growth at various temperatures reveals the existence of two growth regimes. While growth at low temperatures is solely governed by surface diffusion, a combination of decomposition, desorption, and diffusion becomes decisive at growth temperatures of 470 °C and above. At this critical temperature, the surface morphology changes from a grainy structure to a structure made of huge islands. The formation of those islands is attributed to the development of an indium adlayer, which can be observed via reflection high energy electron diffraction monitoring. Based on the growth experiments conducted at temperatures below T{sub Growth} = 470 °C, an activation energy for diffusion of 0.54 ± 0.02 eV has been determined from the decreasing InN island density. A comparison between growth on metalorganic vapor phase epitaxy GaN templates and pseudo bulk GaN indicates that step edges and dislocations are favorable nucleation sites. Based on the results, we developed a growth model, which describes the main mechanisms of the growth.

  1. 21. REAR OF OLD FAITHFUL INN, LOOKING NORTH. SEMICIRCULAR SIDE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. REAR OF OLD FAITHFUL INN, LOOKING NORTH. SEMI-CIRCULAR SIDE DINING ROOM, NOW CALLED THE BEAR PIT WAS ADDED IN 1927. (TAKEN FROM CHERRY-PICKER) - Old Faithful Inn, 900' northeast of Snowlodge & 1050' west of Old Faithful Lodge, Lake, Teton County, WY

  2. Solar Hot Water for Motor Inn--Texas City, Texas

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Final report describes solar domestic-hot-water heater installation at LaQuinta Motor Inn, Texas City, Texas which furnished 63% of total hot-water load of new 98-unit inn. Report presents a description of system, drawings and photographs of collectors, operations and maintenance instructions, manufacturers' specifications for pumps, and an engineer's report on performance.

  3. High-Resolution Group III Nitride Microdisplays

    DTIC Science & Technology

    2011-01-01

    gallium nitride ( InGaN ), the tunable emission wavelength of InGaN , and the ability of the LEDs to be integrated with other functional devices. III...Grayscale projected image of a leopard from a green video graphics array indium gallium nitride ( InGaN ) microdisplay (640 480 pixels, each 12m in size...design and fabrication of an active matrix driver integrated circuit. Finally, it required hybrid integration of the InGaN LED array with the

  4. Angular-dependent Raman study of a- and s-plane InN

    NASA Astrophysics Data System (ADS)

    Filintoglou, K.; Katsikini, M.; Arvanitidis, J.; Christofilos, D.; Lotsari, A.; Dimitrakopulos, G. P.; Vouroutzis, N.; Ajagunna, A. O.; Georgakilas, A.; Zoumakis, N.; Kourouklis, G. A.; Ves, S.

    2015-02-01

    Angular-dependent polarized Raman spectroscopy was utilized to study nonpolar a-plane ( 1 1 ¯ 20 ) and semipolar s-plane ( 10 1 ¯ 1 ) InN epilayers. The intensity dependence of the Raman peaks assigned to the vibrational modes A1(TO), E1(TO), and E2 h on the angle ψ that corresponds to rotation around the growth axis, is very well reproduced by using expressions taking into account the corresponding Raman tensors and the experimental geometry, providing thus a reliable technique towards assessing the sample quality. The s- and a-plane InN epilayers grown on nitridated r-plane sapphire (Al2O3) exhibit good crystalline quality as deduced from the excellent fitting of the experimental angle-dependent peak intensities to the theoretical expressions as well as from the small width of the Raman peaks. On the contrary, in the case of the s-plane epilayer grown on non-nitridated r-plane sapphire, fitting of the angular dependence is much worse and can be modeled only by considering the presence of two structural modifications, rotated so as their c-axes are almost perpendicular to each other. Although the presence of the second variant is verified by transmission electron and atomic force microscopies, angular dependent Raman spectroscopy offers a non-destructive and quick way for its quantification. Rapid thermal annealing of this sample did not affect the angular dependence of the peak intensities. The shift of the E1(TO) and E2 h Raman peaks was used for the estimation of the strain state of the samples.

  5. Angular-dependent Raman study of a- and s-plane InN

    SciTech Connect

    Filintoglou, K.; Katsikini, M. Arvanitidis, J.; Lotsari, A.; Dimitrakopulos, G. P.; Vouroutzis, N.; Ves, S.; Christofilos, D.; Kourouklis, G. A.; Ajagunna, A. O.; Georgakilas, A.; Zoumakis, N.

    2015-02-21

    Angular-dependent polarized Raman spectroscopy was utilized to study nonpolar a-plane (11{sup ¯}20) and semipolar s-plane (101{sup ¯}1) InN epilayers. The intensity dependence of the Raman peaks assigned to the vibrational modes A{sub 1}(TO), E{sub 1}(TO), and E{sub 2}{sup h} on the angle ψ that corresponds to rotation around the growth axis, is very well reproduced by using expressions taking into account the corresponding Raman tensors and the experimental geometry, providing thus a reliable technique towards assessing the sample quality. The s- and a-plane InN epilayers grown on nitridated r-plane sapphire (Al{sub 2}O{sub 3}) exhibit good crystalline quality as deduced from the excellent fitting of the experimental angle-dependent peak intensities to the theoretical expressions as well as from the small width of the Raman peaks. On the contrary, in the case of the s-plane epilayer grown on non-nitridated r-plane sapphire, fitting of the angular dependence is much worse and can be modeled only by considering the presence of two structural modifications, rotated so as their c-axes are almost perpendicular to each other. Although the presence of the second variant is verified by transmission electron and atomic force microscopies, angular dependent Raman spectroscopy offers a non-destructive and quick way for its quantification. Rapid thermal annealing of this sample did not affect the angular dependence of the peak intensities. The shift of the E{sub 1}(TO) and E{sub 2}{sup h} Raman peaks was used for the estimation of the strain state of the samples.

  6. Wet Chemical Etching Survey of III-Nitrides

    SciTech Connect

    Abernathy, C.R.; Cho, H.; Hays, D.C.; MacKenzie, J.D.; Pearton, S.J.; Ren, F.; Shul, R.J.; Vartuli, C.B.; Zolper, J.C.

    1999-02-04

    Wet chemical etching of GaN, InN, AlN, InAlN and InGaN was investigated in various acid and base solutions at temperatures up to 75 C. Only KOH-based solutions were found to etch AlN and InAlN. No etchants were found for the other nitrides, emphasizing their extreme lack of chemical reactivity. The native oxide on most of the nitrides could be removed in potassium tetraborate at 75 C, or HCl/H{sub 2}O at 25 C.

  7. Vertically integrated (Ga, In)N nanostructures for future single photon emitters operating in the telecommunication wavelength range.

    PubMed

    Winden, A; Mikulics, M; Grützmacher, D; Hardtdegen, H

    2013-10-11

    Important technological steps are discussed and realized for future room-temperature operation of III-nitride single photon emitters. First, the growth technology of positioned single pyramidal InN nanostructures capped by Mg-doped GaN is presented. The optimization of their optical characteristics towards narrowband emission in the telecommunication wavelength range is demonstrated. In addition, a device concept and technology was developed so that the nanostructures became singularly addressable. It was found that the nanopyramids emit in the telecommunication wavelength range if their size is chosen appropriately. A p-GaN contacting layer was successfully produced as a cap to the InN pyramids and the top p-contact was achievable using an intrinsically conductive polymer PEDOT:PSS, allowing a 25% increase in light transmittance compared to standard Ni/Au contact technology. Single nanopyramids were successfully integrated into a high-frequency device layout. These decisive technology steps provide a promising route to electrically driven and room-temperature operating InN based single photon emitters in the telecommunication wavelength range.

  8. Local structure of indium oxynitride from x-ray absorption spectroscopy

    SciTech Connect

    T-Thienprasert, J.; Onkaw, D.; Rujirawat, S.; Limpijumnong, S.; Nukeaw, J.; Sungthong, A.; Porntheeraphat, S.; Singkarat, S.

    2008-08-04

    Synchrotron x-ray absorption near edge structures (XANES) measurements of In L{sub 3} edge is used in conjunction with first principles calculations to characterize rf magnetron sputtered indium oxynitride at different O contents. Good agreement between the measured and the independently calculated spectra are obtained. Calculations show that the XANES spectra of this alloy are sensitive to the coordination numbers of the In atoms, i.e., fourfold for indium nitride-like structures and sixfold for indium oxide-like structures, but not to the substitution of nearest neighbor N by O or vice versa.

  9. Indium incorporation into InGaN: The role of the adlayer

    NASA Astrophysics Data System (ADS)

    Rossow, U.; Horenburg, P.; Ketzer, F.; Bremers, H.; Hangleiter, A.

    2017-04-01

    We study the incorporation processes of indium into group-III nitride layers under pulsed and continuous growth conditions by in-situ reflection measurements. We want to clarify which processes limit the incorporation of indium and lead to a degrading layer structure. The data are discussed in the context of the adlayer model proposed by theory [1], which is a liquid-like layer of group-III atoms on the surface. The adlayer is built-up by the incoming flux but the high vapor pressure of indium leads to a high desorption rate and therefore it is apparent in the data only for low growth temperatures. The data suggests that segregated indium on the surface and the environment also contribute to the indium incorporation process likely also via the adlayer.

  10. 17. HIGHWAY 190 ROAD VIEW AT FURNACE CREEK INN. NOTE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. HIGHWAY 190 ROAD VIEW AT FURNACE CREEK INN. NOTE ABANDONED GAS STATION ON LEFT AND ROAD TO BADWATER AT LEFT IN BACKGROUND. LOOKING WSW. - Death Valley National Park Roads, Death Valley Junction, Inyo County, CA

  11. Indium fluoride glass fibers

    NASA Astrophysics Data System (ADS)

    Saad, Mohammed

    2012-03-01

    Fluoride glasses are the only material that transmit light from ultraviolet to mid-infrared and can be drawn into industrial optical fibers. The mechanical and optical properties of new indium fluoride glass fibers have been investigated. Multimode fiber 190 microns, has very high mechanical strength greater than 100 kpsi and optical loss as low as 45 dB/km between 2 and 4 microns. Unlike chalcogenide glass fibers, indium fluoride fiber has a wide transmission window from 0.3 to 5.5 microns without any absorption peak. Indium fluoride glass fibers are the technology of choice for all application requiring transmission up to 5 micron such as infrared contour measure (IRCM) and chemical sensing. Furthermore, Indium fluoride glasses have low phonon energy and can be heavily doped and co-doped whit rare-earth elements. Therefore they are very promising candidates for infrared fiber lasers.

  12. [Indium lung disease].

    PubMed

    Nakano, Makiko; Omae, Kazuyuki

    2014-02-01

    "Indium lung" is a new occupational lung disease. The global demand for indium, the major material used in manufacturing flat-screen display panels, has skyrocketed since the 1990s (Japan comprises 85% of the worldwide demand). The first case was reported in Japan in 2003, followed by seven cases (interstitial pneumonia and emphysema) in Japan. Two pulmonary alveolar proteinosis (PAP) cases in the USA followed in 2011. Indium lung has been described as interstitial pneumonia, pneumothorax, emphysema, and PAP. In 2013, The Japan Ministry of Health, Labor and Welfare issued an "Ordinance on the Prevention of Hazards Due to Specified Chemical Substances" requiring employers to provide regular health checks for employees and measurements of work environment concentrations of respirable indium dust.

  13. Optical properties of InN studied by spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Chunya, Ye; Wei, Lin; Jin, Zhou; Shuping, Li; Li, Chen; Heng, Li; Xiaoxuan, Wu; Songqing, Liu; Junyong, Kang

    2016-10-01

    With recently developed InN epitaxy via a controlling In bilayer, spectroscopic ellipsometry (SE) measurements had been carried out on the grown InN and the measured ellipsometric spectra were fitted with the Delta Psi2 software by using a suitable model and the dispersion rule. The thickness was measured by a scanning electron microscope (SEM). Insight into the film quality of InN and the lattice constant were gained by X-ray diffraction (XRD). By fitting the SE, the thickness of the InN film is consistent with that obtained by SEM cross-sectional thickness measurement. The optical bandgap of InN was put forward to be 1.05 eV, which conforms to the experimental results measured by the absorption spectrum and cathodoluminescence (CL). The refractive index and the extinction coefficient of interest were represented for InN, which is useful to design optoelectronic devices. Project supported by the State Key Development Program for Basic Research of China (No. 2012CB619301), the National High Technology Research and Development Program of China (No. 2014AA032608), the National Natural Science Foundation of China (Nos. 11204254, 11404271), and the Fundamental Research Funds for the Central Universities (Nos. 2012121014, 20720150027).

  14. Indium lung disease.

    PubMed

    Cummings, Kristin J; Nakano, Makiko; Omae, Kazuyuki; Takeuchi, Koichiro; Chonan, Tatsuya; Xiao, Yong-Long; Harley, Russell A; Roggli, Victor L; Hebisawa, Akira; Tallaksen, Robert J; Trapnell, Bruce C; Day, Gregory A; Saito, Rena; Stanton, Marcia L; Suarthana, Eva; Kreiss, Kathleen

    2012-06-01

    Reports of pulmonary fibrosis, emphysema, and, more recently, pulmonary alveolar proteinosis (PAP) in indium workers suggested that workplace exposure to indium compounds caused several different lung diseases. To better understand the pathogenesis and natural history of indium lung disease, a detailed, systematic, multidisciplinary analysis of clinical, histopathologic, radiologic, and epidemiologic data for all reported cases and workplaces was undertaken. Ten men (median age, 35 years) who produced, used, or reclaimed indium compounds were diagnosed with interstitial lung disease 4-13 years after first exposure (n = 7) or PAP 1-2 years after first exposure (n = 3). Common pulmonary histopathologic features in these patients included intraalveolar exudate typical of alveolar proteinosis (n = 9), cholesterol clefts and granulomas (n = 10), and fibrosis (n = 9). Two patients with interstitial lung disease had pneumothoraces. Lung disease progressed following cessation of exposure in most patients and was fatal in two. Radiographic data revealed that two patients with PAP subsequently developed fibrosis and one also developed emphysematous changes. Epidemiologic investigations demonstrated the potential for exposure to respirable particles and an excess of lung abnormalities among coworkers. Occupational exposure to indium compounds was associated with PAP, cholesterol ester crystals and granulomas, pulmonary fibrosis, emphysema, and pneumothoraces. The available evidence suggests exposure to indium compounds causes a novel lung disease that may begin with PAP and progress to include fibrosis and emphysema, and, in some cases, premature death. Prospective studies are needed to better define the natural history and prognosis of this emerging lung disease and identify effective prevention strategies.

  15. Rapid thermal annealing of indium phosphide compound semiconductors

    NASA Technical Reports Server (NTRS)

    Biedenbender, Michael D.; Kapoor, Vik J.; Williams, W. D.

    1987-01-01

    The rapid thermal annealing (RTA) of indium phosphide (InP) substrates using a proximity contact method and silicon nitride encapsulation is investigated. The surface conditions of the InP substrates following cleaning with procedures A and B are analyzed. Procedure A involves using an iodic acid solution to remove work-damage InP surface layers and B is a degasssing process and hydrofluoric acid solution for native oxide removal. AES, XPS, and SIMS data of the proximity contact and silicon nitride encapsulated annealed samples are examined. The data reveal that RTA using proximity contact with silicon wafers does not provide adequate protection; however, the InP sample is successfully annealed when protected by a silicon nitride encapsulant.

  16. Ambient temperature deposition of gallium nitride/gallium oxynitride from a deep eutectic electrolyte, under potential control.

    PubMed

    Sarkar, Sujoy; Sampath, S

    2016-05-11

    A ternary, ionically conducting, deep eutectic solvent based on acetamide, urea and gallium nitrate is reported for the electrodeposition of gallium nitride/gallium indium nitride under ambient conditions; blue and white light emitting photoluminescent deposits are obtained under potential control.

  17. Ultralow wear of gallium nitride

    NASA Astrophysics Data System (ADS)

    Zeng, Guosong; Tan, Chee-Keong; Tansu, Nelson; Krick, Brandon A.

    2016-08-01

    Here, we reveal a remarkable (and surprising) physical property of GaN: it is extremely wear resistant. In fact, we measured the wear rate of GaN is approaching wear rates reported for diamond. Not only does GaN have an ultralow wear rate but also there are quite a few experimental factors that control the magnitude of its wear rate, further contributing to the rich and complex physics of wear of GaN. Here, we discovered several primary controlling factors that will affect the wear rate of III-Nitride materials: crystallographic orientation, sliding environment, and coating composition (GaN, InN and InGaN). Sliding in the ⟨ 1 2 ¯ 10 ⟩ is significantly lower wear than ⟨ 1 1 ¯ 00 ⟩ . Wear increases by 2 orders of magnitude with increasing humidity (from ˜0% to 50% RH). III-Nitride coatings are promising as multifunctional material systems for device design and sliding wear applications.

  18. The INNs and outs of antibody nonproprietary names.

    PubMed

    Jones, Tim D; Carter, Paul J; Plückthun, Andreas; Vásquez, Max; Holgate, Robert G E; Hötzel, Isidro; Popplewell, Andrew G; Parren, Paul W H I; Enzelberger, Markus; Rademaker, Hendrik J; Clark, Michael R; Lowe, David C; Dahiyat, Bassil I; Smith, Victoria; Lambert, John M; Wu, Herren; Reilly, Mary; Haurum, John S; Dübel, Stefan; Huston, James S; Schirrmann, Thomas; Janssen, Richard A J; Steegmaier, Martin; Gross, Jane A; Bradbury, Andrew R M; Burton, Dennis R; Dimitrov, Dimiter S; Chester, Kerry A; Glennie, Martin J; Davies, Julian; Walker, Adam; Martin, Steve; McCafferty, John; Baker, Matthew P

    2016-01-01

    An important step in drug development is the assignment of an International Nonproprietary Name (INN) by the World Health Organization (WHO) that provides healthcare professionals with a unique and universally available designated name to identify each pharmaceutical substance. Monoclonal antibody INNs comprise a -mab suffix preceded by a substem indicating the antibody type, e.g., chimeric (-xi-), humanized (-zu-), or human (-u-). The WHO publishes INN definitions that specify how new monoclonal antibody therapeutics are categorized and adapts the definitions to new technologies. However, rapid progress in antibody technologies has blurred the boundaries between existing antibody categories and created a burgeoning array of new antibody formats. Thus, revising the INN system for antibodies is akin to aiming for a rapidly moving target. The WHO recently revised INN definitions for antibodies now to be based on amino acid sequence identity. These new definitions, however, are critically flawed as they are ambiguous and go against decades of scientific literature. A key concern is the imposition of an arbitrary threshold for identity against human germline antibody variable region sequences. This leads to inconsistent classification of somatically mutated human antibodies, humanized antibodies as well as antibodies derived from semi-synthetic/synthetic libraries and transgenic animals. Such sequence-based classification implies clear functional distinction between categories (e.g., immunogenicity). However, there is no scientific evidence to support this. Dialog between the WHO INN Expert Group and key stakeholders is needed to develop a new INN system for antibodies and to avoid confusion and miscommunication between researchers and clinicians prescribing antibodies.

  19. The INNs and outs of antibody nonproprietary names

    PubMed Central

    Jones, Tim D.; Carter, Paul J.; Plückthun, Andreas; Vásquez, Max; Holgate, Robert G.E.; Hötzel, Isidro; Popplewell, Andrew G.; Parren, Paul W.H.I.; Enzelberger, Markus; Rademaker, Hendrik J.; Clark, Michael R.; Lowe, David C.; Dahiyat, Bassil I.; Smith, Victoria; Lambert, John M.; Wu, Herren; Reilly, Mary; Haurum, John S.; Dübel, Stefan; Huston, James S.; Schirrmann, Thomas; Janssen, Richard A.J.; Steegmaier, Martin; Gross, Jane A.; Bradbury, Andrew R.M.; Burton, Dennis R.; Dimitrov, Dimiter S.; Chester, Kerry A.; Glennie, Martin J.; Davies, Julian; Walker, Adam; Martin, Steve; McCafferty, John; Baker, Matthew P.

    2016-01-01

    An important step in drug development is the assignment of an International Nonproprietary Name (INN) by the World Health Organization (WHO) that provides healthcare professionals with a unique and universally available designated name to identify each pharmaceutical substance. Monoclonal antibody INNs comprise a –mab suffix preceded by a substem indicating the antibody type, e.g., chimeric (-xi-), humanized (-zu-), or human (-u-). The WHO publishes INN definitions that specify how new monoclonal antibody therapeutics are categorized and adapts the definitions to new technologies. However, rapid progress in antibody technologies has blurred the boundaries between existing antibody categories and created a burgeoning array of new antibody formats. Thus, revising the INN system for antibodies is akin to aiming for a rapidly moving target. The WHO recently revised INN definitions for antibodies now to be based on amino acid sequence identity. These new definitions, however, are critically flawed as they are ambiguous and go against decades of scientific literature. A key concern is the imposition of an arbitrary threshold for identity against human germline antibody variable region sequences. This leads to inconsistent classification of somatically mutated human antibodies, humanized antibodies as well as antibodies derived from semi-synthetic/synthetic libraries and transgenic animals. Such sequence-based classification implies clear functional distinction between categories (e.g., immunogenicity). However, there is no scientific evidence to support this. Dialog between the WHO INN Expert Group and key stakeholders is needed to develop a new INN system for antibodies and to avoid confusion and miscommunication between researchers and clinicians prescribing antibodies. PMID:26716992

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

    SciTech Connect

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

    2014-04-07

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

  1. Indium Lung Disease

    PubMed Central

    Nakano, Makiko; Omae, Kazuyuki; Takeuchi, Koichiro; Chonan, Tatsuya; Xiao, Yong-long; Harley, Russell A.; Roggli, Victor L.; Hebisawa, Akira; Tallaksen, Robert J.; Trapnell, Bruce C.; Day, Gregory A.; Saito, Rena; Stanton, Marcia L.; Suarthana, Eva; Kreiss, Kathleen

    2012-01-01

    Background: Reports of pulmonary fibrosis, emphysema, and, more recently, pulmonary alveolar proteinosis (PAP) in indium workers suggested that workplace exposure to indium compounds caused several different lung diseases. Methods: To better understand the pathogenesis and natural history of indium lung disease, a detailed, systematic, multidisciplinary analysis of clinical, histopathologic, radiologic, and epidemiologic data for all reported cases and workplaces was undertaken. Results: Ten men (median age, 35 years) who produced, used, or reclaimed indium compounds were diagnosed with interstitial lung disease 4-13 years after first exposure (n = 7) or PAP 1-2 years after first exposure (n = 3). Common pulmonary histopathologic features in these patients included intraalveolar exudate typical of alveolar proteinosis (n = 9), cholesterol clefts and granulomas (n = 10), and fibrosis (n = 9). Two patients with interstitial lung disease had pneumothoraces. Lung disease progressed following cessation of exposure in most patients and was fatal in two. Radiographic data revealed that two patients with PAP subsequently developed fibrosis and one also developed emphysematous changes. Epidemiologic investigations demonstrated the potential for exposure to respirable particles and an excess of lung abnormalities among coworkers. Conclusions: Occupational exposure to indium compounds was associated with PAP, cholesterol ester crystals and granulomas, pulmonary fibrosis, emphysema, and pneumothoraces. The available evidence suggests exposure to indium compounds causes a novel lung disease that may begin with PAP and progress to include fibrosis and emphysema, and, in some cases, premature death. Prospective studies are needed to better define the natural history and prognosis of this emerging lung disease and identify effective prevention strategies. PMID:22207675

  2. The Children's Inn at NIH - Three Stories | NIH MedlinePlus the Magazine

    MedlinePlus

    ... of this page please turn JavaScript on. Feature: The Children's Inn The Children's Inn at NIH - Three Stories Past Issues / Summer 2014 Table of Contents Kristal Nemeroff—The Patient Kristal Nemeroff, age 2, at the Children's ...

  3. Respirable indium exposures, plasma indium, and respiratory health among indium-tin oxide (ITO) workers.

    PubMed

    Cummings, Kristin J; Virji, M Abbas; Park, Ji Young; Stanton, Marcia L; Edwards, Nicole T; Trapnell, Bruce C; Carey, Brenna; Stefaniak, Aleksandr B; Kreiss, Kathleen

    2016-07-01

    Workers manufacturing indium-tin oxide (ITO) are at risk of elevated indium concentration in blood and indium lung disease, but relationships between respirable indium exposures and biomarkers of exposure and disease are unknown. For 87 (93%) current ITO workers, we determined correlations between respirable and plasma indium and evaluated associations between exposures and health outcomes. Current respirable indium exposure ranged from 0.4 to 108 μg/m(3) and cumulative respirable indium exposure from 0.4 to 923 μg-yr/m(3) . Plasma indium better correlated with cumulative (rs  = 0.77) than current exposure (rs  = 0.54) overall and with tenure ≥1.9 years. Higher cumulative respirable indium exposures were associated with more dyspnea, lower spirometric parameters, and higher serum biomarkers of lung disease (KL-6 and SP-D), with significant effects starting at 22 μg-yr/m(3) , reached by 46% of participants. Plasma indium concentration reflected cumulative respirable indium exposure, which was associated with clinical, functional, and serum biomarkers of lung disease. Am. J. Ind. Med. 59:522-531, 2016. Published 2016. This article is a U.S. Government work and is in the public domain in the USA. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

  4. Respirable Indium Exposures, Plasma Indium, and Respiratory Health Among Indium-Tin Oxide (ITO) Workers

    PubMed Central

    Cummings, Kristin J.; Virji, M. Abbas; Park, Ji Young; Stanton, Marcia L.; Edwards, Nicole T.; Trapnell, Bruce C.; Carey, Brenna; Stefaniak, Aleksandr B.; Kreiss, Kathleen

    2016-01-01

    Background Workers manufacturing indium-tin oxide (ITO) are at risk of elevated indium concentration in blood and indium lung disease, but relationships between respirable indium exposures and biomarkers of exposure and disease are unknown. Methods For 87 (93%) current ITO workers, we determined correlations between respirable and plasma indium and evaluated associations between exposures and health outcomes. Results Current respirable indium exposure ranged from 0.4 to 108 μg/m3 and cumulative respirable indium exposure from 0.4 to 923 μg-yr/m3. Plasma indium better correlated with cumulative (rs = 0.77) than current exposure (rs = 0.54) overall and with tenure ≥1.9 years. Higher cumulative respirable indium exposures were associated with more dyspnea, lower spirometric parameters, and higher serum biomarkers of lung disease (KL-6 and SP-D), with significant effects starting at 22 μg-yr/m3, reached by 46% of participants. Conclusions Plasma indium concentration reflected cumulative respirable indium exposure, which was associated with clinical, functional, and serum biomarkers of lung disease. PMID:27219296

  5. Growth of InN and In rich InGaN by ``High Pressure Chemical Vapor Deposition'' (HPCVD)

    NASA Astrophysics Data System (ADS)

    Buegler, Max; Alevli, Mustafa; Atalay, Ramazan; Durkaya, Goksel; Wang, Jielei; Senevirathna, Indika; Jamil, Muhammad; Ferguson, Ian; Dietz, Nikolaus

    2009-11-01

    We present the growth of III-nitrides under elevated nitrogen pressure to stabilize the growth surface at elevated temperatures. The achievable growth temperatures are significantly higher than in conventional low pressure MOCVD systems. With this the integration of In-rich materials into GaN and GaAlN becomes possible. In addition we present structural and optical properties of thin films grown by HPCVD at a reactor pressure of 15bar and temperatures of 870^oC. The Samples have been analyzed by Raman, optical absorption, IR reflectance and photoluminescence spectroscopy and by XRD. The growth of single phase layers of high crystalline quality has been proven by XRD with InN (0002) Bragg reflex FWHM's of 200arcsec (2θ-φ-scan) and 1600arcsec (rocking curves). These is backed up by Raman spectra with InN E2(high) peak FWHM's of below 10cm-1. Free carrier concentrations in the mid 10^18 cm-3 to low 10^19cm-3 have been calculated from IR reflection spectra. Photoluminescence spectroscopy showed luminescence at 0.77eV.

  6. Solar Hot Water for a Motor Inn -- Las Vegas, Nevada

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Solar hot-water installation at motor inn in Las Vegas, Nevada is described in report containing descriptions of design, philosophy, operation of system and problems and solutions. Provides drawings of solar roof plan, operator's instructions, manufacturers' brochures and copy of acceptance report.

  7. No Vacancy: Inn Provides Revenue Source for Financially Troubled Institute.

    ERIC Educational Resources Information Center

    Bridges, Jerry G.; Brant, Joseph F.

    1994-01-01

    The Peabody Institute of Baltimore (Maryland), the Johns Hopkins University's music school, addressed its financial problems by converting four campus buildings into an inn used to house Elderhostel participants. Annual program revenues cover all costs and yield a financial reserve for the school. (MSE)

  8. Indium Sorption to Iron Oxides

    NASA Astrophysics Data System (ADS)

    White, S. J.; Sacco, S. A.; Hemond, H.; Hussain, F. A.; Runkel, R. L.; Walton-Day, K. E.; Kimball, B. A.; Shine, J. P.

    2014-12-01

    Indium is an increasingly important metal in semiconductors and electronics, and its use is growing rapidly as a semiconductive coating (as indium tin oxide) for liquid crystal displays (LCDs) and flat panel displays. It also has uses in important energy technologies such as light emitting diodes (LEDs) and photovoltaic cells. Despite its rapid increase in use, very little is known about the environmental behavior of indium, and concerns are being raised over the potential health effects of this emerging metal contaminant. One source of indium to the environment is acid mine drainage from the mining of lead, zinc, and copper sulfides. In our previous studies of a stream in Colorado influenced by acid mine drainage from lead and zinc mining activities, indium concentrations were found to be 10,000 times those found in uncontaminated rivers. However, the speciation and mobility of indium could not be reliably modeled because sorption constants to environmental sorbents have not been determined. In this study, we generate sorption constants for indium to ferrihydrite in the laboratory over a range of pHs, sorbent to sorbate ratios, and ionic strengths. Ferrihydrite is one of the most important sorbents in natural systems, and sorption to amorphous iron oxides such as ferrihydrite is thought to be one of the main removal mechanisms of metals from the dissolved phase in aqueous environments. Because of its relatively low solubility, we also find that indium hydroxide precipitation can dominate indium's partitioning at micromolar concentrations of indium. This precipitation may be important in describing indium's behavior in our study stream in Colorado, where modeling sorption to iron-oxides does not explain the complete removal of indium from the dissolved phase when the pH of the system is artificially raised to above 8. This study contributes much-needed data about indium's aqueous behavior, in order to better understand its fate, transport, and impacts in the

  9. Inexpensive Method for Coating the Interior of Silica Growth Ampoules with Pyrolytic Boron Nitride

    NASA Technical Reports Server (NTRS)

    Wang, Jianbin; Regel, Liya L.; Wilcox, William R.

    2003-01-01

    An inexpensive method was developed for coating the interior of silica ampoules with hexagonal boron nitride. An aqueous solution of boric acid was used to coat the ampoule prior to drying in a vacuum at 200 C. This coating was converted to transparent boron nitride by heating in ammonia at 1000 C. Coated ampoules were used to achieve detached solidification of indium antimonide on earth.

  10. Crystalline boron nitride aerogels

    DOEpatents

    Zettl, Alexander K.; Rousseas, Michael; Goldstein, Anna P.; Mickelson, William; Worsley, Marcus A.; Woo, Leta

    2017-04-04

    This disclosure provides methods and materials related to boron nitride aerogels. In one aspect, a material comprises an aerogel comprising boron nitride. The boron nitride has an ordered crystalline structure. The ordered crystalline structure may include atomic layers of hexagonal boron nitride lying on top of one another, with atoms contained in a first layer being superimposed on atoms contained in a second layer.

  11. Precursors for formation of copper selenide, indium selenide, copper indium diselenide, and/or copper indium gallium diselenide films

    DOEpatents

    Curtis, Calvin J; Miedaner, Alexander; Van Hest, Maikel; Ginley, David S

    2014-11-04

    Liquid-based precursors for formation of Copper Selenide, Indium Selenide, Copper Indium Diselenide, and/or copper Indium Galium Diselenide include 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. These liquid-based precursors can be deposited in liquid form onto substrates and treated by rapid thermal processing to form crystalline copper selenide and indium selenide films.

  12. Boron nitride composites

    DOEpatents

    Kuntz, Joshua D.; Ellsworth, German F.; Swenson, Fritz J.; Allen, Patrick G.

    2017-02-21

    According to one embodiment, a composite product includes: a matrix material including hexagonal boron nitride and one or more borate binders; and a plurality of cubic boron nitride particles dispersed in the matrix material. According to another embodiment, a composite product includes: a matrix material including hexagonal boron nitride and amorphous boron nitride; and a plurality of cubic boron nitride particles dispersed in the matrix material.

  13. The anharmonic phonon decay rate in group-III nitrides

    NASA Astrophysics Data System (ADS)

    Srivastava, G. P.

    2009-04-01

    Measured lifetimes of hot phonons in group-III nitrides have been explained theoretically by considering three-phonon anharmonic interaction processes. The basic ingredients of the theory include full phonon dispersion relations obtained from the application of an adiabatic bond charge model and crystal anharmonic potential within the isotropic elastic continuum model. The role of various decay routes, such as Klemens, Ridley, Vallée-Bogani and Barman-Srivastava channels, in determining the lifetimes of the Raman active zone-centre longitudinal optical (LO) modes in BN (zincblende structure) and A1(LO) modes in AlN, GaN and InN (wurtzite structure) has been quantified.

  14. Phonon lifetimes and phonon decay in InN

    NASA Astrophysics Data System (ADS)

    Pomeroy, J. W.; Kuball, M.; Lu, H.; Schaff, W. J.; Wang, X.; Yoshikawa, A.

    2005-05-01

    We report on the Raman analysis of A1(LO) (longitudinal optical) and E2 phonon lifetimes in InN and their temperature dependence from 80 to 700 K. Our experimental results show that among the various possible decay channels, the A1(LO) phonon decays asymmetrically into a high energy and a low energy phonon, whereas the E2 phonon predominantly decays into three phonons. Possible decay channels of the A1(LO) phonon may involve combinations of transverse optical and acoustic phonons. Phonon lifetimes of 1.3 and 4 ps were measured at 80 K for the A1(LO) and the E2 phonons, respectively. This rather long A1(LO) phonon lifetime suggests that hot phonon effects will play a role in InN for carrier relaxation.

  15. High rate dry etching of GaN, AlN and InN in ECR Cl{sub 2}/CH{sub 4}/H{sub 2}/Ar plasmas

    SciTech Connect

    Vartuli, C.B.; Pearton, S.J.; Abernathy, C.R.; Shul, R.J.; Kilcoyne, S.P.; Crawford, M.H.; Howard, A.J.; Parmeter, J.E.

    1995-05-01

    Etch rates for binary nitrides in ECR Cl{sub 2}/CH{sub 4}/H{sub 2}/Ar are reported as a function of temperature, rf-bias, microwave power, pressure and relative gas proportions. GaN etch rates remain relatively constant from 30 to 125{degrees}C and then increase to a maximum of 2340 {angstrom}-min{sup {minus}1} at 170{degrees}C. The AlN etch rate decreases throughout the temperature range studied with a maximum of 960 {angstrom}-min{sup {minus}1} at 30{degrees}C. When CH{sub 4} is removed from the plasma chemistry, the GaN and InN etch rates are slightly lower, with less dramatic changes with temperature. The surface composition of the III-V nitrides remains unchanged over the temperatures studied. The GaN and InN rates increase significantly with rf power, and the fastest rates for all three binaries are obtained at 2 mTorr. Surface morphology is smooth for GaN over a wide range of conditions, whereas InN surfaces are more sensitive to plasma parameters.

  16. Temperature switching of cavity modes in InN microcrystals

    SciTech Connect

    Kazanov, D. R. Kaibyshev, V. H.; Davydov, V. Yu.; Smirnov, A. N.; Jmerik, V. N.; Kuznetsova, N. V.; Kopiev, P. S.; Ivanov, S. V.; Shubina, T. V.

    2015-11-15

    InN optical cavities supporting low-order whispering-gallery modes up to room temperature are formed by molecular-beam epitaxy on patterned substrates. The observed switching of the mode type with increasing temperature is explained in terms of changes in the optical parameters due to a shift of the absorption edge and modification of its shape. Modeling taking into account a variation in the refractive index reproduces the typical distributions of the electromagnetic-field intensity in the cavities.

  17. Mineral of the month: indium

    USGS Publications Warehouse

    George, Micheal W.

    2004-01-01

    Indium was discovered in Germany in 1863. Although it is a lustrous silver-white color, the finders named the new material for the “indigo” spectral lines the mineral created on the spectrograph. Indium ranks 61st in abundance in Earth’s crust and is about three times more abundant than silver or mercury.

  18. Auger Recombination in Indium Gallium Nitride: Experimental Evidence

    NASA Astrophysics Data System (ADS)

    Krames, Michael

    2010-03-01

    Progress in InGaN-based light-emitting diode (LED) technology has resulted in white-light emitters with efficiencies far exceeding those of conventional light sources such as tungsten-filament-based incandescence and mercury-vapor based fluorescence. Indeed, by now efficacies exceeding 150 lumens per Watt for InGaN-based phosphor-converted white LEDs are claimed, which represent a 90% energy savings compared to the conventional incandescent (i.e., ``light bulb'') solution. However, these high performance levels are obtained under conditions of very low forward current-density for the InGaN LED and do not represent true operating conditions (nor cost-effective utilization) for the device. In order to reduce the cost (and thus increase market penetration of) solid-state lighting, more lumens per unit of semiconductor area are required which in practice necessitates higher drive current densities. Unfortunately, at these higher driver current densities, the internal quantum efficiency of InGaN-based LEDs is observed to decrease significantly. In the fall of 2007, researchers at the Advanced Laboratories of Philips Lumileds were the first to propose Auger recombination as the root-cause mechanism in InGaN which was behind this ``efficiency droop'' [1]. They further proposed to circumvent the problem by employing InGaN-based active region designs that maintain low carrier density, and demonstrated an LED device design that reaches a maximum quantum efficiency above 200 A/cm2, compared to ˜1-10 A/cm^2 for typical multiple-quantum-well heterostructures [2]. In this talk we will review the experimental evidence for Auger recombination in InGaN, beginning with the early work from 2007 and then considering additional work from more recent efforts to better understand the details behind this loss mechanism. [4pt] [1] Y. C. Shen, G. O. M"uller, S. Watanabe, N. F. Gardner, A. Munkholm, and M. R. Krames, ``Auger recombination in InGaN measured by photoluminescence'', Appl. Phys. Lett. 91, 141101 (2007). [0pt] [2] N. F. Gardner, G. O. M"uller, Y. C. Shen, G. Chen, S. Watanabe, W. G"otz, and M. R. Krames, ``Blue-emitting InGaN--GaN double-heterostructure light-emitting diodes reaching maximum quantum efficiency above 200 A/cm^2'', Appl. Phys. Lett. 91, 243506 (2007).

  19. Improved characteristics of indium gallium nitride-based laser diodes

    NASA Astrophysics Data System (ADS)

    Hansen, Monica Cecilia

    2001-10-01

    Many applications exist for short wavelength laser diodes (lambda ˜ 400--450 nm), such as optical storage, laser printing, displays, and lighting, as well as medical applications. The operating characteristics and lifetimes of InGaN-based laser diodes need be improved to provide the reliability required for these applications. These improvements require extensive work in the growth and design of the epitaxial layer structure, as well as the device design and fabrication. The epitaxial structure of the laser was investigated to enhance the operating characteristics. Optimization in the epitaxial design and growth conditions of the laser active region, claddings, and p-type layers was performed. The design of the quantum wells (QWs) and QW capping reduced the threshold current density of the laser and doubled the internal efficiency to 35%. The implementation of AlGaN/GaN strained-layer superlattices improved the structural properties of the cladding layers. Optimizing the Mg-doping in the laser reduces the resistivity of the p-type layers and the threshold voltage by 30%, thus reducing the heating of the lasers. The increased hole concentration with a reduced Mg-doping decreases the threshold current and increases the internal efficiency. The device design and fabrication was also addressed. Facet formation improvements were investigated to increase the facet reflectivity. Heat sinking was also investigated to provide heat extraction from the device. The devices were able to operate under a 10% duty cycle when the substrate was thinned and mounted on a copper heat sink, compared to 2% with no heat sinking. The threading dislocation (TD) density in the laser structure has a large impact on the threshold current density of laser diodes. The TDs act as nonradiative recombination centers, which will reduce the internal efficiency of the laser diode. Removing the dislocations by the lateral epitaxial overgrowth (LEO) technique led to extraordinary improvements in device performance and is the enabling step for the demonstration of long-lifetime blue laser diodes. The threshold current density of lasers on LEO GaN was as low as 3.7 kA/cm 2, which is a factor of 2 lower than lasers on conventional GaN. The internal efficiency is increased from 3% to 22% when reducing the dislocation density. The TD distribution also had an impact on the growth mode and resulting surface morphology of laser diodes. Spirals are formed around the terminations of TD with a screw component and the changing in TD density on LEO GaN will drastically impact the spiral size in the laser structures. The growth of laser diodes on SiC was investigated to take advantage of the thermal and conductive properties of the substrate over the typically employed sapphire substrates. Buffer layers need to be optimized to provide a low resistance at the interface and a low threading dislocation density, in order to surpass the performance of lasers on sapphire.

  20. Nanostructures of Indium Gallium Nitride Crystals Grown on Carbon Nanotubes

    PubMed Central

    Park, Ji-Yeon; Man Song, Keun; Min, Yo-Sep; Choi, Chel-Jong; Seok Kim, Yoon; Lee, Sung-Nam

    2015-01-01

    Nanostructure (NS) InGaN crystals were grown on carbon nanotubes (CNTs) using metalorganic chemical vapor deposition. The NS-InGaN crystals, grown on a ~5-μm-long CNT/Si template, were estimated to be ~100–270 nm in size. Transmission electron microscope examinations revealed that single-crystalline InGaN NSs were formed with different crystal facets. The observed green (~500 nm) cathodoluminescence (CL) emission was consistent with the surface image of the NS-InGaN crystallites, indicating excellent optical properties of the InGaN NSs on CNTs. Moreover, the CL spectrum of InGaN NSs showed a broad emission band from 490 to 600 nm. Based on these results, we believe that InGaN NSs grown on CNTs could aid in overcoming the green gap in LED technologies. PMID:26568414

  1. Nanostructures of Indium Gallium Nitride Crystals Grown on Carbon Nanotubes.

    PubMed

    Park, Ji-Yeon; Man Song, Keun; Min, Yo-Sep; Choi, Chel-Jong; Seok Kim, Yoon; Lee, Sung-Nam

    2015-11-16

    Nanostructure (NS) InGaN crystals were grown on carbon nanotubes (CNTs) using metalorganic chemical vapor deposition. The NS-InGaN crystals, grown on a ~5-μm-long CNT/Si template, were estimated to be ~100-270 nm in size. Transmission electron microscope examinations revealed that single-crystalline InGaN NSs were formed with different crystal facets. The observed green (~500 nm) cathodoluminescence (CL) emission was consistent with the surface image of the NS-InGaN crystallites, indicating excellent optical properties of the InGaN NSs on CNTs. Moreover, the CL spectrum of InGaN NSs showed a broad emission band from 490 to 600 nm. Based on these results, we believe that InGaN NSs grown on CNTs could aid in overcoming the green gap in LED technologies.

  2. Recent developments in nitride chemistry

    SciTech Connect

    Niewa, R.; DiSalvo, F.J.

    1998-10-01

    The chemistry of ternary nitrides is reviewed with special focus on developments of the last two years (1996 and 1997). In particular, structures and properties of ternary and higher transition metal nitrides, main group nitrides, subnitrides, and nitride halides are compared, and a section on thermodynamics of ternary nitrides is included. Finally, methods for the preparation of gallium nitride single crystals are summarized.

  3. Estimations of the spontaneous polarization of binary and ternary compounds of group III nitrides

    NASA Astrophysics Data System (ADS)

    Davydov, S. Yu.; Posrednik, O. V.

    2016-04-01

    The dependences of spontaneous polarizations P sp of solid solutions of aluminum, gallium, and indium nitrides on the compositions were estimated using the Harrison bond-orbital method. A simple formula was proposed to estimate P sp using only lengths of the interatomic bonds between the nearest neighbor atoms and the angles between these bonds.

  4. Titanium Nitride Cermets

    DTIC Science & Technology

    1952-07-01

    7696i ’-Brewer, L., et al. Thermodynamic and Physical Properties of Nitrides. Carbides, Sulfides, i1licides, and Phosphides, Chemistry and Metallurgy of...12 Referen eCs 0 . ...................... • • • 14 WADC TR 52-155 iv LIST OF TABLES I Properties of Titanium Nitride Bodies...15 II Properties of Titanium Nitride-Nickel Bodies............16 III Properties of Titanium Nitride Cermets with Nickel,..... 17 Cobalt, and

  5. Lattice polarity detection of InN by circular photogalvanic effect

    SciTech Connect

    Zhang, Q.; Wang, X. Q.; He, X. W.; Yin, C. M.; Xu, F. J.; Shen, B.; Chen, Y. H.; Wang, Z. G.; Ishitani, Y.; Yoshikawa, A.

    2009-07-20

    We report an effective and nondestructive method based on circular photogalvanic effect (CPGE) to detect the lattice polarity of InN. Because of the lattice inversion between In- and N-polar InN, the energy band spin splitting is opposite for InN films with different polarities. Consequently under light irradiation with the same helicity, CPGE photocurrents in In- and N-polar layers will have opposite directions, thus the polarity can be detected. This method is demonstrated by our CPGE measurements in both n- and p-type InN films.

  6. Lattice polarity detection of InN by circular photogalvanic effect

    NASA Astrophysics Data System (ADS)

    Zhang, Q.; Wang, X. Q.; He, X. W.; Yin, C. M.; Xu, F. J.; Shen, B.; Chen, Y. H.; Wang, Z. G.; Ishitani, Y.; Yoshikawa, A.

    2009-07-01

    We report an effective and nondestructive method based on circular photogalvanic effect (CPGE) to detect the lattice polarity of InN. Because of the lattice inversion between In- and N-polar InN, the energy band spin splitting is opposite for InN films with different polarities. Consequently under light irradiation with the same helicity, CPGE photocurrents in In- and N-polar layers will have opposite directions, thus the polarity can be detected. This method is demonstrated by our CPGE measurements in both n- and p-type InN films.

  7. Prediction of rock salt structure of (InN)32 nanoparticles from first principles calculations.

    PubMed

    Kaur, Prabhsharan; Sekhon, S S; Kumar, Vijay

    2013-03-21

    From first principles calculations, we show that (InN)32 nanoparticles favor rock salt structure compared with wurtzite structure in bulk. A phase transition from wurtzite to rock salt structure is known to occur in bulk InN at 12.1 GPa and higher values of pressure for AlN and GaN. However, at the nanoscale we show that this structural transition takes place in (InN)32 without applying pressure. The charge asymmetry value "g" and cation/anion size ratio in InN describe very well this behavior. Similar studies on nanoparticles of AlN and GaN as well as a few other binary compounds such as MgS, AgI, ZnO, and CdSe, however, do not show such a transition. Our results suggest (InN)32 to be a unique candidate as further calculations on a few larger size (InN)n nanoparticles show that a filled cage (two shells) (InN)12@(InN)48 structure of (InN)60 has higher binding energy compared with a rock salt structure of (InN)64 leading to the conclusion that other 3D structures are likely to become favorable over rock salt structure for larger sizes.

  8. Convergence of valence bands for high thermoelectric performance for p-type InN

    NASA Astrophysics Data System (ADS)

    Li, Hai-Zhu; Li, Ruo-Ping; Liu, Jun-Hui; Huang, Ming-Ju

    2015-12-01

    Band engineering to converge the bands to achieve high valley degeneracy is one of effective approaches for designing ideal thermoelectric materials. Convergence of many valleys in the valence band may lead to a high Seebeck coefficient, and induce promising thermoelectric performance of p-type InN. In the current work, we have systematically investigated the electronic structure and thermoelectric performance of wurtzite InN by using the density functional theory combined with semiclassical Boltzmann transport theory. Form the results, it can be found that intrinsic InN has a large Seebeck coefficient (254 μV/K) and the largest value of ZeT is 0.77. The transport properties of p-type InN are better than that of n-type one at the optimum carrier concentration, which mainly due to the large Seebeck coefficient for p-type InN, although the electrical conductivity of n-type InN is larger than that of p-type one. We found that the larger Seebeck coefficient for p-type InN may originate from the large valley degeneracy in the valence band. Moreover, the low minimum lattice thermal conductivity for InN is one key factor to become a good thermoelectric material. Therefore, p-type InN could be a potential material for further applications in the thermoelectric area.

  9. Preparation of uranium nitride

    DOEpatents

    Potter, Ralph A.; Tennery, Victor J.

    1976-01-01

    A process for preparing actinide-nitrides from massive actinide metal which is suitable for sintering into low density fuel shapes by partially hydriding the massive metal and simultaneously dehydriding and nitriding the dehydrided portion. The process is repeated until all of the massive metal is converted to a nitride.

  10. Ordered arrays of bottom-up III-nitride core-shell nanostructures

    NASA Astrophysics Data System (ADS)

    Rishinaramangalam, Ashwin K.; Nami, Mohsen; Bryant, Benjamin N.; Eller, Rhett F.; Shima, Darryl M.; Fairchild, Michael N.; Balakrishnan, Ganesh; Brueck, S. R. J.; Feezell, Daniel F.

    2015-08-01

    The growth of ordered arrays of group III-nitride nanostructures on c-plane gallium nitride (GaN) on sapphire using selective-area metal organic chemical vapor deposition (MOCVD) is presented. The growth of these nanostructures promotes strain relaxation that allows the combination of high indium content active regions with very low dislocation densities and also gives access to nonpolar and semipolar crystallographic orientations of GaN. The influence of the starting template and the growth conditions on the growth rate and morphology is discussed. The growth of indium gallium nitride (InGaN) active region shells on these nanostructures is discussed and the stability of various crystallographic orientations under typical growth conditions is studied. Finally, the effect of the growth conditions on the morphology of pyramidal stripe LEDs is discussed and preliminary results on electrical injection of these LEDs are presented.

  11. Applying the INN model to the MaxClique problem

    SciTech Connect

    Grossman, T.

    1993-09-01

    Max-Clique is the problem of finding the largest clique in a given graph. It is not only NP-hard, but, as recent results suggest, even hard to approximate. Nevertheless it is still very important to develop and test practical algorithms that will find approximate solutions for the maximum clique problem on various graphs stemming from numerous applications. Indeed, many different types of algorithmic approaches are applied to that problem. Several neural networks and related algorithms were applied recently to combinatorial optimization problems in general and to the Max-Clique problem in particular. These neural nets are dynamical system which minimize a cost (or computational ``energy``) function that represents the optimization problem, the Max-Clique in our case. Therefore they all belong to the class of integer programming algorithms surveyed in the Pardalos and Xue review. The work presented here is a development and improvement of a neural network algorithm that was introduced recently. In the previous work, we have considered two Hopfield type neural networks, the INN and the HcN, and their application to the max-clique problem. In this paper, I concentrate on the INN network and present an improved version of the t-A algorithm that was introduced in. The rest of this paper is organized as follows: in section 2, I describe the INN model and how it implements a given graph. In section 3, it is characterized in terms of graph theory. In particular, the stable states of the network are mapped to the maximal cliques of its underling graph. In section 4, I present the t-Annealing algorithm and an improved version of it, the Adaptive t-Annealing. Several experiments done with these algorithms on benchmark graphs are reported in section 5, and the efficiency of the new algorithm is demonstrated. I conclude with a short discussion.

  12. Transmission Electron Microscopy Study of InN Nanorods

    SciTech Connect

    Liliental-Weber, Z.; Li, X.; Kryliouk, Olga; Park, H.J.; Mangum,J.; Anderson, T.

    2006-07-13

    InN nanorods were grown on a, c-, and r-plane of sapphire and also on Si (111) and GaN (0001) by non-catalytic, template-free hydride metal-organic vapor phase epitaxy and studied by transmission electron microscopy, electron energy loss (EELS) and photoluminescence (PL) at room temperature. These nanocrystals have different shapes and different faceting depending on the substrate used and their crystallographic orientation. EELS measurements have confirmed the high purity of these crystals. The observed PL peak was in the range of 0.9-0.95 eV. The strongest PL intensity was observed for the nanocrystals with the larger diameters.

  13. Temperature sensitive photoconductivity observed in InN layers

    NASA Astrophysics Data System (ADS)

    Guo, Lei; Wang, Xinqiang; Feng, Li; Zheng, Xiantong; Chen, Guang; Yang, Xuelin; Xu, Fujun; Tang, Ning; Lu, Liwu; Ge, Weikun; Shen, Bo

    2013-02-01

    Photoconductivity has been systematically studied in unintentionally doped n-type InN film with super-bandgap excitation (1.53 eV) at temperatures varying in the range of 100-300 K. A negative photoconductivity is observed at room temperature, whereas it gradually changes to be positive with decreasing temperature. Transition temperature from negative to positive photoconductivity is found to be greatly related to the residual electron concentration as the higher the electron concentration, the lower the transition temperature. An energy band model including a donor state with large lattice relaxation as well as a recombination center is proposed, which explains the experimental observation well.

  14. International Symposium on the Growth of III-Nitrides (ISGN), May 18-22, 2014, Atlanta GA

    DTIC Science & Technology

    2015-03-31

    U.S. Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 Growth of III-Nitrides, epitaxial growth techniques , ternary and...latest work in the technical areas shown below. ISGN-5 Symposium topics • III-N Bulk growth: AlN, GaN, InN • Epitaxial growth techniques ...Tokuyama Corporation, Japan Yoshinao Kumagai, Tokyo University of Agriculture and Technology, Japan Robert Leute, University of Ulm, Germany Wsevolod

  15. The Little Inn at the Crossroads: A Spiritual Approach to the Design of a Leadership Course.

    ERIC Educational Resources Information Center

    Bento, Regina F.

    2000-01-01

    A course on spiritual dimensions of leadership was designed using the metaphor of an inn at a crossroads. The inn included a virtual library of Web-based texts and studio space for creativity and self-expression. Seven workshops explored the following themes: language of leadership and change, personal leadership qualities, vision and mission,…

  16. Electronic structures and work functions of InN(0001) films

    NASA Astrophysics Data System (ADS)

    Song, Jung-Hwan; Freeman, Arthur J.

    2007-03-01

    InN films have attracted great attention with its recently discovered band gap, 0.7eV, and evidence for p-type doping. We have studied theoretically the electronic structures, surfaces, and work functions of InN films using the highly precise FLAPW method. The passivation with pseudo-hydrogens has also been applied to the surfaces of InN(0001) films for comparison with the electronic structure of the ideal InN(0001) films. We compare the work functions of InN films with other wurtzite materials such as ZnO, GaN, and AlN, which we have also calculated. We discuss the mechanism of the structural transition with layer thickness for the very thin InN(0001) films, for which we have found that the ideal InN(0001) films of the wurtzite structure, up to 4 bilayers, optimize to the graphitic- like structure. We then discuss the relationship between the dipoles and the surfaces (work functions) of the InN(0001) films, and the possibilities of their p-type doping. R.E. Jones, et al, Phys. Rev. Lett, 96, 125505 (2006). Wimmer, Krakauer, Weinert, Freeman, Phys. Rev. B, 24, 864 (1981). K. Shiraishi, J. Phys. Soc. Jpn, 59, 3455 (1990) C. L. Freeman, et al, Phys. Rev. Lett, 96, 066102 (2006)

  17. NIH's "Family Inn" Lets Out-of-Town Youngsters Stay "Home."

    ERIC Educational Resources Information Center

    Somerville, Sylvia

    1993-01-01

    The Children's Inn, on the grounds of the National Institutes for Health (NIH) near Washington, DC, serves as a national model of the value of family-centered homes for pediatric patients and their families. When parents bring their child to NIH from a distant place, they can stay in the inn with their child while the child is receiving treatment.…

  18. Inn1 couples contraction of the actomyosin ring to membrane ingression during cytokinesis in budding yeast.

    PubMed

    Sanchez-Diaz, Alberto; Marchesi, Vanessa; Murray, Stephen; Jones, Richard; Pereira, Gislene; Edmondson, Ricky; Allen, Terry; Labib, Karim

    2008-04-01

    By rapidly depleting each of the essential budding yeast proteins of unknown function, we identified a novel factor that we call Inn1, which associates with the contractile actomyosin ring at the end of mitosis and is needed for cytokinesis. We show that Inn1 has a C2 domain at the amino terminus of the protein that is required for ingression of the plasma membrane, whereas the remainder of the protein recruits Inn1 to the actomyosin ring. The lethal effects of deleting the INN1 gene can be suppressed by artificial fusion of the C2 domain to other components of the actomyosin ring, restoring membrane ingression on contraction of the actomyosin ring. Our data indicate that recruitment of the C2 domain of Inn1 to the contractile actomyosin ring is crucial for ingression of the plasma membrane during cytokinesis in budding yeast.

  19. Direct current magnetron sputtering deposition of InN thin films

    NASA Astrophysics Data System (ADS)

    Cai, Xing-Min; Hao, Yan-Qing; Zhang, Dong-Ping; Fan, Ping

    2009-10-01

    In this paper, InN thin films were deposited on Si (1 0 0) and K9 glass by reactive direct current magnetron sputtering. The target was In metal with the purity of 99.999% and the gases were Ar (99.999%) and N 2 (99.999%). The properties of InN thin films were studied. Scanning electron microscopy (SEM) shows that the film surface is very rough and energy dispersive X-ray spectroscopy (EDX) shows that the film contains In, N and very little O. X-ray diffraction (XRD) and Raman scattering reveal that the film mainly contains hexagonal InN. The four-probe measurement shows that InN film is conductive. The transmission measurement demonstrates that the transmission of InN deposited on K9 glass is as low as 0.5% from 400 nm to 800 nm.

  20. Nitride semiconductors for ultraviolet detection

    NASA Astrophysics Data System (ADS)

    Davis, R. F.; Bremser, M. D.; Gruss, K.; Linthicum, K.; Ferry, B.

    1995-06-01

    Continued development and commercialization of optoelectronic devices, including light emitting diodes and semiconductor lasers produced from 3-5 gallium arsenide-based materials, has also generated interest in the much wider bandgap semiconductor mononitride materials containing aluminum, gallium, and indium. The majority of the studies have been conducted on pure gallium nitride thin films having the wurtzite structure, and this emphasis continues to the present day. The program objectives achieved in this reporting period have been (1) the growth of undoped, high resistivity and n- and p-type doped monocrystalline, GaN thin films on alpha(6H)-SiC(000l) wafers via organometallic vapor phase epitaxy (OMVPE), and their characterization via photoluminescence; (2) the growth and cathodoluminescence characterization of Al(x)Ga(1-x)N alloys and abrupt heterojunctions of these alloys; (3) the development and application of a novel NH3 cracker cell for gas source MBE to reduce film damage; and (4) the reactive ion etching of undoped GaN films via use of Cl-containing compounds.

  1. Indium Gallium Nitride/Gallium Nitride (InGaN/GaN) Nanorods Superlattice (SL)

    DTIC Science & Technology

    2006-03-29

    distinct dislocation network and side wall damage are observed as shown in the upper inset of Fig. 10 which indicates an image of transmission electron...Phys. 76, 304 (1994). [42] W. I. Lee, T. C. Huang, J. Guo, and M. S. Feng, Appl. Phys. Lett. 67, 1721 (1995). [43] D. G. Thomas, J. J. Hopfield , and W

  2. Geothermal heating facilities for Frontier Inn, Susanville, California

    NASA Astrophysics Data System (ADS)

    1982-03-01

    A 38 unit motel composed of six major sections (coffee shop, A frame units, apartments, back units, two story units and office) was built over a number of years and exhibits widely varying types of construction. Space heating is provided by primarily electric resistance equipment with some propane use. Domestic hot water is provided primarily by propane with some electric resistance. The coffee shop uses fuel oil for both space and domestic hot water heating. A geothermal district heating system is being installed. Although the motel site is not located in the area of construction activity, it is expected that the pipeline will be extended. The potential of retrofitting the existing heating facilities at the inn to geothermal is studied.

  3. Indium oxide based fiber optic SPR sensor

    SciTech Connect

    Shukla, Sarika; Sharma, Navneet K.

    2016-05-06

    Surface plasmon resonance based fiber optic sensor using indium oxide layer is presented and theoretically studied. It has been found that with increase in thickness of indium oxide layer beyond 170 nm, the sensitivity of SPR sensor decreases. 170 nm thick indium oxide layer based SPR sensor holds maximum sensitivity.

  4. Indium Foil Serves As Thermally Conductive Gasket

    NASA Technical Reports Server (NTRS)

    Eastman, G. Yale; Dussinger, Peter M.

    1993-01-01

    Indium foil found useful as gasket to increase thermal conductance between bodies clamped together. Deforms to fill imperfections on mating surfaces. Used where maximum temperature in joint less than melting temperature of indium. Because of low melting temperature of indium, most useful in cryogenic applications.

  5. Indium Foil Serves As Thermally Conductive Gasket

    NASA Technical Reports Server (NTRS)

    Eastman, G. Yale; Dussinger, Peter M.

    1993-01-01

    Indium foil found useful as gasket to increase thermal conductance between bodies clamped together. Deforms to fill imperfections on mating surfaces. Used where maximum temperature in joint less than melting temperature of indium. Because of low melting temperature of indium, most useful in cryogenic applications.

  6. Methods of forming boron nitride

    DOEpatents

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

    2015-03-03

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

  7. Indium-Mediated Stereoselective Allylation.

    PubMed

    Kumar, Dinesh; Vemula, Sandeep R; Balasubramanian, Narayanaganesh; Cook, Gregory R

    2016-10-04

    Stereoselective indium-mediated organic reactions have enjoyed tremendous growth in the last 25 years. This is in part due to the insensitivity of allylindium to moisture, affording facile and practical reaction conditions coupled with outstanding functional group tolerance and minimal side reactions. Despite the plethora of articles about allylindium, there is much yet to be discovered and exploited for efficient and sustainable synthesis. In this Account, we describe indium-mediated synthetic methods for the preparation of chiral amines with the aim to present a balance of practical method development, novel asymmetric chemistry, and mechanistic understanding that impact multiple chemical and materials science disciplines. In 2005, we demonstrated the indium-mediated allylation of chiral hydrazones with complete diastereoselectivity (>99:1) and quantitative yields. Further, we revealed the first example of enantioselective indium-mediated allylation of hydrazones using catalytic (R)-3,3'-bis(trifluoromethyl)-BINOL ligands to afford homoallylic amines with high enantioselectivity. The use of enantiopure perfluoroalkylsulfonate BINOLs greatly improved the indium-mediated allylation of N-acylhydrazones with exquisite enantiocontrol (99% yield, 99% ee). This laboratory has also investigated indium-mediated asymmetric intramolecular cyclization in the presence of amino acid additives to deliver biologically relevant chromanes with excellent diastereoselectivity (dr >99:1). The effect of amino acid additives (N-Boc-glycine) was further investigated during the indium-mediated allylation of isatins with allyl bromide to yield homoallylic alcohols in excellent yields in a short time with a wide range of functional group tolerance. Critical mechanistic insight was gained, and evidence suggests that the additive plays two roles: (1) to increase the rate of formation of allylindium from allyl bromide and In(0) and (2) to increase the nucleophilicity of the allylindium

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

    DOEpatents

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

    2011-11-15

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

  9. Indium droplet formation in InGaN thin films with single and double heterojunctions prepared by MOCVD

    PubMed Central

    2014-01-01

    Indium gallium nitride (InGaN) samples with single heterojunction (SH) and double heterojunction (DH) were prepared using metal-organic chemical vapor deposition. SH has a layer of InGaN thin film (thicknesses, 25, 50, 100, and 200 nm) grown on an uGaN film (thickness, 2 μm). The DH samples are distinguished by DH uGaN film (thickness, 120 nm) grown on the InGaN layer. Reciprocal space mapping measurements reveal that the DH samples are fully strained with different thicknesses, whereas the strain in the SH samples are significantly relaxed with the increasing thickness of the InGaN film. Scanning electron microscopy results show that the surface roughness of the sample increases when the sample is relaxed. High-resolution transmission electron microscopy images of the structure of indium droplets in the DH sample indicate that the thickness of the InGaN layer decreases with the density of indium droplets. The formation of these droplets is attributed to the insufficient kinetic energy of indium atom to react with the elements of group V, resulting to aggregation. The gallium atoms in the GaN thin film will not be uniformly replaced by indium atoms; the InGaN thin film has an uneven distribution of indium atoms and the quality of the epitaxial layer is degraded. PMID:25024692

  10. Intrinsic electronic properties of high-quality wurtzite InN

    NASA Astrophysics Data System (ADS)

    Eisele, H.; Schuppang, J.; Schnedler, M.; Duchamp, M.; Nenstiel, C.; Portz, V.; Kure, T.; Bügler, M.; Lenz, A.; Dähne, M.; Hoffmann, A.; Gwo, S.; Choi, S.; Speck, J. S.; Dunin-Borkowski, R. E.; Ebert, Ph.

    2016-12-01

    Recent reports suggested that InN is a highly unusual III-V semiconductor, whose behavior fundamentally differs from that of others. We therefore analyzed its intrinsic electronic properties on the highest available quality InN layers, demonstrating the absence of electron accumulation at the (10 1 ¯0 ) cleavage surface and in the bulk. The bulk electron density is governed solely by dopants. Hence, we conclude that InN acts similarly to the other III-V semiconductors and previously reported intriguing effects are related to low crystallinity, surface decomposition, nonstoichiometry, and/or In adlayers.

  11. Selective-Area Growth of Transferable InN Nanocolumns by Using Anodic Aluminum Oxide Nanotemplates

    NASA Astrophysics Data System (ADS)

    Wang, Xiao; Zhang, Guozhen; Xu, Yang; Wu, Hao; Liu, Chang

    2017-02-01

    InN nanocolumn arrays were grown on c-plane sapphire with and without anodic aluminum oxide (AAO) nanotemplates. The crystalline quality of InN nanocolumns was significantly improved by selective-area growth (SAG) using AAO templates, as verified by X-ray diffraction measurements. Then, InN nanocolumns were transferred onto p-type silicon substrates after etching off the AAO templates. Current-voltage characteristic of the transferred n-InN/p-Si heterojunctions shows on/off ratio as high as 4.65 × 103 at 2 V. This work offers a potential way to grow transferable devices with improving performances.

  12. X-ray diffraction of III-nitrides

    NASA Astrophysics Data System (ADS)

    Moram, M A; Vickers, M E

    2009-03-01

    The III-nitrides include the semiconductors AlN, GaN and InN, which have band gaps spanning the entire UV and visible ranges. Thin films of III-nitrides are used to make UV, violet, blue and green light-emitting diodes and lasers, as well as solar cells, high-electron mobility transistors (HEMTs) and other devices. However, the film growth process gives rise to unusually high strain and high defect densities, which can affect the device performance. X-ray diffraction is a popular, non-destructive technique used to characterize films and device structures, allowing improvements in device efficiencies to be made. It provides information on crystalline lattice parameters (from which strain and composition are determined), misorientation (from which defect types and densities may be deduced), crystallite size and microstrain, wafer bowing, residual stress, alloy ordering, phase separation (if present) along with film thicknesses and superlattice (quantum well) thicknesses, compositions and non-uniformities. These topics are reviewed, along with the basic principles of x-ray diffraction of thin films and areas of special current interest, such as analysis of non-polar, semipolar and cubic III-nitrides. A summary of useful values needed in calculations, including elastic constants and lattice parameters, is also given. Such topics are also likely to be relevant to other highly lattice-mismatched wurtzite-structure materials such as heteroepitaxial ZnO and ZnSe.

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

    DOEpatents

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

    1989-07-04

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

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

    DOEpatents

    Murduck, James M.; Lepetre, Yves J.; Schuller, Ivan K.; Ketterson, John B.

    1989-01-01

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

  15. FOREWORD: The physics of III-V nitrides The physics of III-V nitrides

    NASA Astrophysics Data System (ADS)

    Ridley, B. K.

    2009-04-01

    The evolution of semiconductor physics is driven by the increasing sophistication of the art of crystal growing and fabrication techniques. From Ge at the birth of the transistor, possibly the purest material ever grown, through Si, the work-horse of the crystal revolution, to the III-Vs, whose optical properties opened up a second front, namely, optoelectronics. Crystal growth with monolayer control gave us quantum wells, superlattices, quantum wires and quantum dots, along with the quantum Hall effect and quantized resistance. The potential for high-power devices triggered interest in the III-V nitrides with their large bandgaps. The nitrides mostly crystallize in the hexagonal form, and this has introduced the phenomenon of spontaneous polarization into mainstream semiconductor physics. Its effect manifests itself in huge electric fields in heterostructures like AlGaN/GaN which, in turn, causes the induction of substantial electron populations in the channel of a HFET without the need for doping. High-power microwave transistors have been successfully fabricated, even though there are features associated with spontaneous polarization that still needs clarifying. Another strange effect is the large electron population on the surface of InN. The lack of a suitable substrate for growing GaN has meant that the dislocation density is higher than we would wish, but that situation is expected to steadily improve. Given the current interest in the physics of nitrides, it is natural to come across a special issue devoted to this topic. The difficulty presented by the surface layer in InN in the attempt to measure transport properties is discussed in the paper by King et al. A property that can affect transport is the lifetime of optical phonons and its dependence on electron density. Measurements of phonon lifetime in InN are reported by Tsen and Ferry, and in GaN channels, via the measure of hot-electron fluctuations, by Matulionis. The dependence on electron density is

  16. Indium lung--case reports and epidemiology.

    PubMed

    Omae, Kazuyuki; Nakano, Makiko; Tanaka, Akiyo; Hirata, Miyuki; Hamaguchi, Tsutahiro; Chonan, Tatsuya

    2011-06-01

    The present review is aimed to introduce an new occupational lung disease, Indium Lung. We searched case reports and epidemiological studies concerning indium-related lung diseases and reviewed. Up to March, 2010, 7 cases of interstitial pneumonia in Japanese indium-exposed workers, two cases of pulmonary alveolar proteinosis (PAP) in US indium-exposed workers, one case of PAP in a Chinese indium-exposed worker, and 4 cross-sectional surveys in Japan had been published. All cases and epidemiological studies in Japan indicate that exposure to hardly soluble indium compounds causes interstitial as well as emphysematous lung damages, which we call "Indium Lung". Based on the epidemiological studies, the Japan Society for Occupational Health proposed 3 μg/l of indium in serum as an occupational exposure limit based on biological monitoring to prevent significant increase of KL-6. Long-term follow-up of currently and formerly indium-exposed workers is essential not only to clarify the natural history of indium lung but also to trace the incidence of lung cancer. It is also necessary to elucidate the mechanism of indium lung and difference in clinical manifestations between Japanese and US cases.

  17. Method for preparing actinide nitrides

    DOEpatents

    Bryan, G.H.; Cleveland, J.M.; Heiple, C.R.

    1975-12-01

    Actinide nitrides, and particularly plutonium and uranium nitrides, are prepared by reacting an ammonia solution of an actinide compound with an ammonia solution of a reactant or reductant metal, to form finely divided actinide nitride precipitate which may then be appropriately separated from the solution. The actinide nitride precipitate is particularly suitable for forming nuclear fuels.

  18. Boron doped GaN and InN: Potential candidates for spintronics

    NASA Astrophysics Data System (ADS)

    Fan, S. W.; Huang, X. N.; Yao, K. L.

    2017-02-01

    The full potential linearized augmented plane wave method together with the Tran-Blaha modified Becke-Johnson potential is utilized to investigate the electronic structures and magnetism for boron doped GaN and InN. Calculations show the boron substituting nitrogen (BN defects) could induce the GaN and InN to be half-metallic ferromagnets. The magnetic moments mainly come from the BN defects, and each BN defect would produce the 2.00 μB total magnetic moment. The electronic structures indicate the carriers-mediated double exchange interaction plays a crucial role in forming the ferromagnetism. Positive chemical pair interactions imply the BN defects would form the homogeneous distribution in GaN and InN matrix. Moderate formation energies suggest that GaN and InN with BN defects could be fabricated experimentally.

  19. Ambient pressure, low-temperature synthesis and characterization of colloidal InN nanocrystals

    PubMed Central

    Hsieh, Jennifer C.; Yun, Dong Soo; Hu, Evelyn

    2014-01-01

    Highly soluble, non-aggregated colloidal wurtzite InN nanocrystals were obtained through an ambient pressure, low-temperature method followed by post-synthesis treatment with nitric acid. PMID:25484524

  20. An investigation of electronic and optical properties of InN nanosheet by first principle study

    NASA Astrophysics Data System (ADS)

    Farzan, M.; Elahi, S. M.; Salehi, H.; Abolhassani, M. R.

    2017-07-01

    In this work, we investigated electronic and optical properties of InN nanosheet using density function theory (DFT) implemented in Wien2k code. We calculated the dielectric function, absorption coefficient, optical conductivity, refraction index, extinction index, reflectivity, and energy loss function of the InN nanosheet within GGA (PBE) and Engel-Vosko (E.V) approximation in two directions E||x (electric field parallel to nanosheet) and E||z (electric field perpendicular to nanosheet), we also calculated the band gap energy within GGA (PBE) and E.V approximations. Optical conductivity in directions to x and z shows that InN nanosheet has semiconductor properties. At the end, we calculated electronic and optical properties, and elastic constant of InN Bulk (wurtzite).

  1. Ultra-low threshold gallium nitride photonic crystal nanobeam laser

    SciTech Connect

    Niu, Nan Woolf, Alexander; Wang, Danqing; Hu, Evelyn L.; Zhu, Tongtong; Oliver, Rachel A.; Quan, Qimin

    2015-06-08

    We report exceptionally low thresholds (9.1 μJ/cm{sup 2}) for room temperature lasing at ∼450 nm in optically pumped Gallium Nitride (GaN) nanobeam cavity structures. The nanobeam cavity geometry provides high theoretical Q (>100 000) with small modal volume, leading to a high spontaneous emission factor, β = 0.94. The active layer materials are Indium Gallium Nitride (InGaN) fragmented quantum wells (fQWs), a critical factor in achieving the low thresholds, which are an order-of-magnitude lower than obtainable with continuous QW active layers. We suggest that the extra confinement of photo-generated carriers for fQWs (compared to QWs) is responsible for the excellent performance.

  2. Gallium nitride nanowires by maskless hot phosphoric wet etching

    NASA Astrophysics Data System (ADS)

    Bharrat, D.; Hosalli, A. M.; Van Den Broeck, D. M.; Samberg, J. P.; Bedair, S. M.; El-Masry, N. A.

    2013-08-01

    We demonstrate gallium nitride (GaN) nanowires formation by controlling the selective and anisotropic etching of N-polar GaN in hot phosphoric acid. Nanowires of ˜109/cm,2 total height of ˜400 nm, and diameters of 170-200 nm were obtained. These nanowires have both non-polar {11¯00}/ {112¯0} and semi-polar {1011¯} facets. X-Ray Diffraction characterization shows that screw dislocations are primarily responsible for preferential etching to create nanowires. Indium gallium nitride multi-quantum wells (MQWs) grown on these GaN nanowires showed a blue shift in peak emission wavelength of photoluminescence spectra, and full width at half maximum decreased relative to MQWs grown on planar N-polar GaN, respectively.

  3. Boron nitride - Composition, optical properties, and mechanical behavior

    NASA Technical Reports Server (NTRS)

    Pouch, John J.; Alterovitz, Samuel A.; Miyoshi, Kazuhisa; Warner, Joseph D.

    1987-01-01

    A low energy ion beam deposition technique was used to grow boron nitride films on quartz, germanium, silicon, gallium arsenide, and indium phosphate. The film structure was amorphous with evidence of a hexagonal phase. The peak boron concentration was 82 at. percent. The carbon and oxygen impurities were in the 5 to 8 at. percent range. Boron-nitrogen and boron-boron bonds were revealed by X-ray photoelectron spectroscopy. The index of refraction varied from 1.65 to 1.67 for films deposited on III-V compound semiconductors. The coefficient of friction for boron nitride in sliding contact with diamond was less than 0.1. The substrate was silicon.

  4. Boron nitride: Composition, optical properties and mechanical behavior

    NASA Technical Reports Server (NTRS)

    Pouch, John J.; Alterovitz, Samuel A.; Miyoshi, Kazuhisa; Warner, Joseph D.

    1987-01-01

    A low energy ion beam deposition technique was used to grow boron nitride films on quartz, germanium, silicon, gallium arsenide, and indium phosphate. The film structure was amorphous with evidence of a hexagonal phase. The peak boron concentration was 82 at %. The carbon and oxygen impurities were in the 5 to 8 at % range. Boron-nitrogen and boron-boron bonds were revealed by X-ray photoelectron spectroscopy. The index of refraction varied from 1.65 to 1.67 for films deposited on III-V compound semiconductors. The coefficient of friction for boron nitride in sliding contact with diamond was less than 0.1. The substrate was silicon.

  5. Orthogonal and Non-Orthogonal Tight Binding Parameters for III-V Semiconductors Nitrides

    NASA Astrophysics Data System (ADS)

    Martins, A. S.; Fellows, C. E.

    2016-12-01

    A simulated annealing (SA) approach is employed in the determination of different tight binding (TB) sets of parameters for the nitride semiconductors AlN, GaN and InN, as well their limitations and potentialities are also discussed. Two kinds of atomic basis set are considered: (i) the orthogonal sp 3 s∗ with interaction up to second neighbors and (ii) a spd non-orthogonal set, with the Hamiltonian matrix elements calculated within the Extended Hückel Theory (EHT) prescriptions. For the non-orthogonal method, TB parameters are given for both zincblend and wurtzite crystalline structures.

  6. Raman and optical studies of indium rich In_1-xAl_xN thin films

    NASA Astrophysics Data System (ADS)

    Haddad, D.; Danylyuk, Y. V.; Naik, R.; Auner, G. W.; Naik, V. M.

    2002-03-01

    Indium rich In_1-xAl_xN films with x = 0 -0.2 have been grown by Plasma Source Molecular Beam Epitaxy on Sapphire (0001) substrate at growth temperature in the range of 300 - 500 ^oC. X-ray diffraction measurements show that films are polycrystalline at low growth temperatures with increased c-axis texture at higher temperatures. Raman spectra of InN films show the characteristic wurtzite A_1(LO), A_1(TO) and E2 phonon modes with a significant disorder activated mode broadening . The direct energy bandgap of alloy films were determined using optical (UV-Vis) transmission and reflection measurements. The optical absorption spectra show a stronger plasma absorption confirming the presence of higher carrier concentration in InN films compared to the alloy films. The results of photoluminescence measurements on these films using 2.41 eV excitation energy (> energy bandgap of the samples studied here) will also be presented.

  7. Synthesis and characterization of InP and InN colloidal quantum dots.

    SciTech Connect

    Boyle, Timothy J.; Osinski, Marek; Greenberg, Melisa; Bunge, Scott D.; Chen, Weiliang; Smolyakov, G. A.; Pulford, B. N.; Jiang, Ying-Bing

    2005-04-01

    InP quantum dots (QDs) with zinc blende structure and InN QDs with hexagonal structure were synthesized from appropriate organometallic precursors in a noncoordinating solvent using myristic acid as a ligand. The QDs were characterized by TEM, the associated energy dispersive spectroscopy (EDS), electron diffraction, and steady state UV-VIS optical absorption and photoluminescence spectroscopy. To our best knowledge, this paper reports synthesis of InN colloidal quantum dots for the first time.

  8. Urbach's tail in III-nitrides under an electric field

    NASA Astrophysics Data System (ADS)

    Rodrigues, Clóves G.; Vasconcellos, Áurea R.; Luzzi, Roberto; Freire, V. N.

    2001-08-01

    We consider electron-hole recombination in wide-gap strong-polar semiconductors of the III-nitride family under high electric fields. The calculated low-energy side of the luminescense spectrum displays the so-called Urbach's tail, which is characterized as resulting from the presence of sidebands in the form of replicas of the main band, corresponding to recombination with accompanying emission of one, two, etc., LO phonons. The influence of the nonequilibrium macroscopic state of hot carriers and phonons on the luminescence spectrum is evidenced. Our results for a 45 kV/cm electric field intensity point to 50, 120, and 220 meV Urbach tail widths in, respectively, wurtzite InN, GaN, and AlN.

  9. Ohmic contacts on binary and ternary III-nitrides

    SciTech Connect

    Ren, F.; Pearton, S.J.; Donovan, S.; Abernathy, C.R.; Cole, M.W.

    1996-12-31

    Tungsten based ohmic contacts on GaN, InN, InAlN, and InN/graded-In{sub x}Al{sub 1{minus}x}N/InAlN were investigated. For GaN, annealing at temperatures between 600 and 800 C exhibited specific contact resistance of 10{sup {minus}5} {Omega}-cm{sup 2} and limited elemental diffusion. For the case of In contained material systems, the contacts are stable up to 500 C and show lower contact resistance (in the range of high 10{sup {minus}6} to low 10{sup {minus}7} {Omega}-cm{sup 2}) due to higher doping level in In contained nitrides.

  10. Urbach's tail in III-nitrides under an electric field

    SciTech Connect

    Rodrigues, Cloves G.; Vasconcellos, Aurea R.; Luzzi, Roberto; Freire, V. N.

    2001-08-15

    We consider electron-hole recombination in wide-gap strong-polar semiconductors of the III-nitride family under high electric fields. The calculated low-energy side of the luminescense spectrum displays the so-called Urbach's tail, which is characterized as resulting from the presence of sidebands in the form of replicas of the main band, corresponding to recombination with accompanying emission of one, two, etc., LO phonons. The influence of the nonequilibrium macroscopic state of hot carriers and phonons on the luminescence spectrum is evidenced. Our results for a 45 kV/cm electric field intensity point to 50, 120, and 220 meV Urbach tail widths in, respectively, wurtzite InN, GaN, and AlN. {copyright} 2001 American Institute of Physics.

  11. Growth of very large InN microcrystals by molecular beam epitaxy using epitaxial lateral overgrowth

    SciTech Connect

    Kamimura, J.; Kishino, K.; Kikuchi, A.

    2015-02-28

    Very thick InN (∼40 μm) was grown by molecular beam epitaxy using the epitaxial lateral overgrowth (ELO) technique. In some regions, the ELO of InN was observed as expected, indicating an important step toward fabricating quasi-bulk InN substrates. Interestingly, most parts of the sample consist of large flat-topped microcrystals and well-faceted microstructures. This is likely due to local growth condition variations during ELO, which is supported by an experiment where ELO of InN was performed on a substrate with various stripe mask patterns. TEM characterization of a flat top InN microcrystal revealed few stacking faults and only related threading dislocations. Defect-free small faceted microcrystals were also observed. The thick InN crystals show a narrow photoluminescence spectrum with a peak at 0.679 eV and linewidth of 16.8 meV at 4 K.

  12. First-principles study of optical properties of InN nanosheet

    NASA Astrophysics Data System (ADS)

    Sarmazdeh, Masoud Majidiyan; Mendi, Roohallah Taghavi; Zelati, Amir; Boochani, Arash; Nofeli, Fariba

    2016-05-01

    Based on density functional theory (DFT), some optical properties of InN nanosheet, such as dielectric function, energy loss function, refractive index, reflectivity and absorption coefficient, have been calculated using the modified Becke-Johnson (mBJ) exchange-correlation potential and full potential-linearized augmented plane waves (FP-LAPW) method. The study of dielectric function show that optical properties of InN nanosheet are anisotropic and important energy range in the optical process is between low energies to 20 eV. The results indicate the plasmon energy of InN nanosheet occurs in the lower energy than bulk InN and in addition the plasmon energy in the in-plane direction is different from that perpendicular to the in-plane direction. The obtained optical gaps are 1.2 eV and 3.6 eV in perpendicular and parallel to c-axis, respectively. Study of refractive index and optical reflectivity shows that the superluminal phenomena occur in the several energy ranges for the InN nanosheet and this nanosheet has high transparency in a wide energy range. The results propose that the InN nanosheet is a good candidate for the optical communications applications, optoelectronics devices and transparent coatings.

  13. Synthesis and characterization of InN nanocrystals on glass substrate by plasma assisted reactive evaporation

    NASA Astrophysics Data System (ADS)

    Ganesh, V.; Alizadeh, M.; Shuhaimi, A.; Sundaram, S.; Hakim, K. M.; Goh, B. T.; Rahman, S. A.

    2017-07-01

    InN nanocrystals were grown on glass substrate by plasma assisted reactive evaporation technique and the quality was compared with InN on Si (111) substrate. Single phase InN was confirmed by X-ray diffraction and micro Raman analysis on both the substrates. Agglomerated and Hexagonal faceting nanocrystals observed by field emission scanning electron microscopy. Energy dispersive X-ray analysis shows InN nanocrystals are nearly stochiometric. Photoluminescence reveals a broad emission near bandedge at 2 .04 eV and defect band at 1.07 eV. The Hall measurement on both the substrates reveals high electron carrier concentration. These encouraging results obtained suggested that high quality single crystalline InN can be obtained on glass substrate further optimizing the growth parameters. This novel growth of InN nanocrystals on glass substrate is an important step towards the development of monolithic, high efficiency low-cost InGaN-based renewable energy sources.

  14. Aluminum Nitride Crystal Growth

    DTIC Science & Technology

    1979-12-01

    UOSR-TR- 80 - 04 2 4EL4- G LEYEL ALUMINUM NITRIDE CRYSTAL GROWTH G.A. Slack FINAL REPORT Contract F49620-78-C-0021 DTIC Period Covered ELECTE I...Laboratory personnel worked on the problem of Aluminum Nitride Heat Sink Crystal Growth for the U.S. Air Force Office of Scientific Research under Contract...Number F44620-76-C-0039. From November 1, 1977 to the present we have worked on Aluminum Nitride and Boron Phosphide Crystal Growth under Contract NUmber

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

    DOEpatents

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

    2014-07-22

    A temperature stable (color and efficiency) III-nitride based amber (585 nm) light-emitting diode is based on a novel hybrid nanowire-planar structure. The arrays of GaN nanowires enable radial InGaN/GaN quantum well LED structures with high indium content and high material quality. The high efficiency and temperature stable direct yellow and red phosphor-free emitters enable high efficiency white LEDs based on the RGYB color-mixing approach.

  16. Synthesis of aluminium nitride/boron nitride composite materials

    SciTech Connect

    Xiao, T.D. . Polymer Science Program and Dept. of Chemistry); Gonsalves, K.E. . Polymer Science Program and Dept. of Chemistry Univ. of Connecticut, Storrs, CT . Dept. of Chemistry); Strutt, P.R. . Dept. of Metallurgy)

    1993-04-01

    Aluminum nitride/boron nitride composite was synthesized by using boric acid, urea, and aluminum chloride (or aluminum lactate) as the starting compounds. The starting materials were dissolved in water and mixed homogeneously. Ammonolysis of this aqueous solution resulted in the formation of a precomposite gel, which converted into the aluminum nitride/boron nitride composite on further heat treatment. Characterization of both the precomposite and the composite powders included powder X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. Analysis of the composite revealed that the aluminum nitride phase had a hexagonal structure, and the boron nitride phase a turbostratic structure.

  17. III-Nitride Vertical-Cavity Surface-Emitting Lasers

    NASA Astrophysics Data System (ADS)

    Leonard, John T.

    Vertical-cavity surface-emitting lasers (VCSELs) have a long history of development in GaAs-based and InP-based systems, however III-nitride VCSELs research is still in its infancy. Yet, over the past several years we have made dramatic improvements in the lasing characteristics of these highly complex devices. Specifically, we have reduced the threshold current density from ˜100 kA/cm2 to ˜3 kA/cm2, while simultaneously increasing the output power from ˜10 muW to ˜550 muW. These developments have primarily come about by focusing on the aperture design and intracavity contact design for flip-chip dual dielectric DBR III-nitride VCSELs. We have carried out a number of studies developing an Al ion implanted aperture (IIA) and photoelectrochemically etched aperture (PECA), while simultaneously improving the quality of tin-doped indium oxide (ITO) intracavity contacts, and demonstrating the first III-nitride VCSEL with an n-GaN tunnel junction intracavity contact. Beyond these most notable research fronts, we have analyzed numerous other parameters, including epitaxial growth, flip-chip bonding, substrate removal, and more, bringing further improvement to III-nitride VCSEL performance and yield. This thesis aims to give a comprehensive discussion of the relevant underlying concepts for nonpolar VCSELs, while detailing our specific experimental advances. In Section 1, we give an overview of the applications of VCSELs generally, before describing some of the potential applications for III-nitride VCSELs. This is followed by a summary of the different material systems used to fabricate VCSELs, before going into detail on the basic design principles for developing III-nitride VCSELs. In Section 2, we outline the basic process and geometry for fabricating flip-chip nonpolar VCSELs with different aperture and intracavity contact designs. Finally, in Section 3 and 4, we delve into the experimental results achieved in the last several years, beginning with a discussion on

  18. Gallium nitride optoelectronic devices

    NASA Technical Reports Server (NTRS)

    Chu, T. L.; Chu, S. S.

    1972-01-01

    The growth of bulk gallium nitride crystals was achieved by the ammonolysis of gallium monochloride. Gallium nitride single crystals up to 2.5 x 0.5 cm in size were produced. The crystals are suitable as substrates for the epitaxial growth of gallium nitride. The epitaxial growth of gallium nitride on sapphire substrates with main faces of (0001) and (1T02) orientations was achieved by the ammonolysis of gallium monochloride in a gas flow system. The grown layers had electron concentrations in the range of 1 to 3 x 10 to the 19th power/cu cm and Hall mobilities in the range of 50 to 100 sq cm/v/sec at room temperature.

  19. Boron Nitride Nanotubes

    NASA Technical Reports Server (NTRS)

    Smith, Michael W. (Inventor); Jordan, Kevin (Inventor); Park, Cheol (Inventor)

    2012-01-01

    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.

  20. Boron nitride nanotubes

    DOEpatents

    Smith, Michael W [Newport News, VA; Jordan, Kevin [Newport News, VA; Park, Cheol [Yorktown, VA

    2012-06-06

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

  1. Boron nitride composites

    DOEpatents

    Kuntz, Joshua D.; Ellsworth, German F.; Swenson, Fritz J.; Allen, Patrick G.

    2016-02-16

    According to one embodiment, a composite product includes hexagonal boron nitride (hBN), and a plurality of cubic boron nitride (cBN) particles, wherein the plurality of cBN particles are dispersed in a matrix of the hBN. According to another embodiment, a composite product includes a plurality of cBN particles, and one or more borate-containing binders.

  2. RF-Molecular Beam Epitaxy Growth and Properties of InN and Related Alloys

    NASA Astrophysics Data System (ADS)

    Nanishi, Yasushi; Saito, Yoshiki; Yamaguchi, Tomohiro

    2003-05-01

    The fundamental band gap of InN has been thought to be about 1.9 eV for a long time. Recent developments of metalorganic vapor phase epitaxy (MOVPE) and RF-molecular beam epitaxy (RF-MBE) growth technologies have made it possible to obtain high-quality InN films. A lot of experimental results have been presented very recently, suggesting that the true band-gap energy of InN should be less than 1.0 eV. In this paper, we review the results of the detailed study of RF-MBE growth conditions for obtaining high-quality InN films. The full widths at half maximum (FWHMs) of ω-mode X-ray diffraction (XRD), ω-2θ mode XRD and E2 (high-frequency)-phonon-mode peaks in the Raman scattering spectrum of the grown layer were 236.7 arcsec, 28.9 arcsec and 3.7 cm-1, respectively. The carrier concentration and room temperature electron mobility were 4.9× 1018 cm-3 and 1130 cm2/Vs, respectively. Photoluminescence and optical absorption measurements of these high-quality InN films have clearly demonstrated that the fundamental band gap of InN is about 0.8 eV. Studies on the growth and characterization of InGaN alloys over the entire alloy composition further supported that the fundamental band gap of InN is about 0.8 eV.

  3. The electronic structures of AlN and InN wurtzite nanowires

    NASA Astrophysics Data System (ADS)

    Xiong, Wen; Li, Dong-Xiao

    2017-07-01

    We derive the relations between the analogous seven Luttinger-Kohn parameters and six Rashba-Sheka-Pikus parameters for wurtzite semiconductors, which can be used to investigate the electronic structures of some wurtzite semiconductors such as AlN and InN materials, including their low-dimensional structures. As an example, the electronic structures of AlN and InN nanowires are calculated by using the derived relations and six-band effective-mass k · p theory. Interestingly, it is found that the ground hole state of AlN nanowires is always a pure S state whether the radius R is small (1 nm) or large (6 nm), and the ground hole state only contains | Z > Bloch orbital component. Therefore, AlN nanowires is the ideal low-dimensional material for the production of purely linearly polarized π light, unlike ZnO nanowires, which emits plane-polarized σ light. However, the ground hole state of InN nanowires can be tuned from a pure S state to a mixed P state when the radius R is larger than 2.6 nm, which will make the polarized properties of the lowest optical transition changes from linearly polarized π light to plane-polarized σ light. Meanwhile, the valence band structures of InN nanowires will present strong band-crossings when the radius R increases to 6 nm, and through the detail analysis of possible transitions of InN nanowires at the Γ point, we find some of the neighbor optical transitions are almost degenerate, because the spin-orbit splitting energy of InN material is only 0.001 eV. Therefore, it is concluded that the electronic structures and optical properties of InN nanowires present great differences with that of AlN nanowires.

  4. Relation Between Structural and Optical Properties of InN and InxGa1-xN Thin Films

    DTIC Science & Technology

    2009-01-01

    Keywords: InN InGaN structural and optical properties Abstract: <p>Transmission Electron Microscopy (TEM) and optical measurements obtained from InN and...In1-xGaxNfilms (0 < x < 0.54) grown by Molecular Beam Epitaxy are presented. Energy gaps measured byabsorption, PR, and PL for InN films grown on c...and optical measurements obtained from InN and In1-xGaxN films (0 < x < 0.54) grown by Molecular Beam Epitaxy are presented. Energy gaps measured by

  5. Abnormal Nitride Morphologies upon Nitriding Iron-Based Substrates

    NASA Astrophysics Data System (ADS)

    Meka, Sai Ramudu; Mittemeijer, Eric Jan

    2013-06-01

    Nitriding of iron-based components is a very well-known surface engineering method for bringing about great improvement of the mechanical and chemical properties. An overview is presented of the strikingly different nitride morphologies developing upon nitriding iron-based alloy substrates. Observed abnormal morphologies are the result of intricate interplay of the thermodynamic and kinetic constraints for the nucleation and growth of both alloying element nitride particles in the matrix and iron nitrides at the surface of the substrate. Alloying elements having strong Me-N interaction, such as Cr, V, and Ti, precipitate instantaneously as internal Me-nitrides, thus allowing the subsequent nucleation and growth of "normal" layer-type iron nitride. Alloying elements having weak Me-N interaction, such as Al, Si, and Mo, and simultaneously having low solubility in iron nitride, obstruct/delay the nucleation and growth of iron nitrides at the surface, thus leading to very high nitrogen supersaturation over an extended depth range from the surface. Eventually, the nucleation and growth of "abnormal" plate-type iron nitride occurs across the depth range of high nitrogen supersaturation. On this basis, strategies can be devised for tuned development of specific nitride morphologies at the surface of nitrided components.

  6. Influence of Metallic Indium Concentration on the Properties of Indium Oxide Thin Films

    NASA Astrophysics Data System (ADS)

    Kalkan, N.

    2016-10-01

    Current-voltage characteristics of indium-embedded indium oxide thin films (600-850 Å), with Ag electrodes approximately 1000 Å thick, prepared by reactive evaporation of pure metallic indium in partial air pressure have been studied for substrate temperatures between 50 and 125°C. The optical properties of these films have also been investigated as a function of metallic indium concentration and substrate temperature. I-V characteristics of all the samples are non-ohmic, independent of metallic indium concentration. The conductivity of the films increases but the optical transmission decreases with increasing metallic indium concentration. Metallic indium concentration was found to be an important parameter affecting the film properties. Furthermore, two possible conduction mechanisms are proposed.

  7. Anisotropy of the nitrogen conduction states in the group III nitrides studied by polarized x-ray absorption

    SciTech Connect

    Lawniczak-Jablonska, K. |; Liliental-Weber, Z.; Gullikson, E.M.

    1997-04-01

    Group III nitrides (AlN, GaN, and InN) consist of the semiconductors which appear recently as a basic materials for optoelectronic devices active in the visible/ultraviolet spectrum as well as high-temperature and high-power microelectronic devices. However, understanding of the basic physical properties leading to application is still not satisfactory. One of the reasons consists in unsufficient knowledge of the band structure of the considered semiconductors. Several theoretical studies of III-nitrides band structure have been published but relatively few experimental studies have been carried out, particularly with respect to their conduction band structure. This motivated the authors to examine the conduction band structure projected onto p-states of the nitrogen atoms for AlN, GaN and InN. An additional advantage of their studies is the availability of the studied nitrides in two structures, hexagonal (wurtzite) and cubic (zincblende). This offers an opportunity to gain information about the role of the anisotropy of electronic band states in determining various physical properties.

  8. Process for Patterning Indium for Bump Bonding

    NASA Technical Reports Server (NTRS)

    Denis, Kevin

    2012-01-01

    An innovation was created for the Cosmology Large Angular Scale Surveyor for integration of low-temperature detector chips with a silicon backshort and a silicon photonic choke through flipchip bonding. Indium bumps are typically patterned using liftoff processes, which require thick resist. In some applications, it is necessary to locate the bumps close to high-aspect-ratio structures such as wafer through-holes. In those cases, liftoff processes are challenging, and require complicated and time-consuming spray coating technology if the high-aspect-ratio structures are delineated prior to the indium bump process. Alternatively, processing the indium bumps first is limited by compatibility of the indium with subsequent processing. The present invention allows for locating bumps arbitrarily close to multiple-level high-aspect-ratio structures, and for indium bumps to be formed without liftoff resist. The process uses the poor step coverage of indium deposited on a silicon wafer that has been previously etched to delineate the location of the indium bumps. The silicon pattern can be processed through standard lithography prior to adding the high-aspect-ratio structures. Typically, high-aspectratio structures require a thick resist layer so this layer can easily cover the silicon topography. For multiple levels of topography, the silicon can be easily conformally coated through standard processes. A blanket layer of indium is then deposited onto the full wafer; bump bonding only occurs at the high points of the topography.

  9. Occupational Exposure to Indium of Indium Smelter Workers.

    PubMed

    Ding, Chun Guang; Wang, Huan Qiang; Song, Han Bo; Li, Zhi Hui; Li, Xiao Ping; Ye, Shao Se; Zhang, Fu Gang; Cui, Shi Wei; Yan, Hui Fang; Li, Tao

    2016-05-01

    Case reports of indium-related lung disease in workers have raised public concern to the human toxicity of indium (In) and its compounds. However, studies evaluating the exposure or health of workers in In smelting plants are rare. Therefore, in this study, we focused on four In smelting plants, with the main objective of characterizing In in smelter plants in China and discussing the potential exposure biomarkers of In exposure. We recruited 494 subjectsat four In smelting plants in China. Personal air samples, first morning urine and spot blood samples were collected. In concentrations in samples were analyzed using inductively coupled plasma mass spectrometry. In concentrations in air samples did not exceed the permissible concentration-time weighed average, but the smelter workers had a higher internal exposure to In. Positive correlations were observed between the air In and urine In concentrations, and between the air In and blood In concentrations. This study provides basic data for the following In exposure and health risk assessment. Copyright © 2016 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

  10. Progress and prospects of group-III nitride semiconductors

    NASA Astrophysics Data System (ADS)

    Mohammad, S. N.; Morkoç, H.

    We review recent progress in the group-III nitride and related materials, and electronic and optical devices based on them. Blue and UV (e.g. ultra violet) emitters and detectors, and high temperature/high power electronics which has long been coveted are beginning to be realized either in the laboratory or in the commercial arena, due in part to the breathtaking progress made in the last few years in the art and science of GaN, InN, AlN and their salloys. With brief references to the historical aspect of the relevant developments, this review concerns itself primarily with the current status of wide bandgap gallium nitride and related semiconductors from both the materials and devices points of view. Following a discussion of the structural properties of these materials, their electrical and optical properties are described in detail. The available data on metal contacts, the properties of which are indeed very conducive for the devices mentioned, from the points of view of ohmic contacts and Schottky barriers, are elaborated on. Recent progress on processing issues such as etching are reviewed. The review then embarks on an indash;depth discussion and analysis of field effect transistors, bipolar transistors, light emitting diodes, laser and photo detectors.

  11. EDITORIAL: Non-polar and semipolar nitride semiconductors Non-polar and semipolar nitride semiconductors

    NASA Astrophysics Data System (ADS)

    Han, Jung; Kneissl, Michael

    2012-02-01

    topics including growth and heteroepitaxy, bulk GaN substrates, theory and modelling, optical properties, laser diodes and LEDs as well as transport properties and electronics. Farrell et al review materials and growth issues for high-performance non- and semipolar light-emitting devices, and Scholz provides an overview of heteroepitaxial growth of semipolar GaN. Okada et al review growth mechanisms of non- and semipolar GaN layers on patterned sapphire substrates, and Vennéguès discusses defect reduction methods for heteroepitaxially grown non- and semipolar III-nitride films. Leung et al explain how kinetic Wulff plots can be used to design and control non-polar and semipolar GaN heteroepitaxy, and a contribution by Sawaki et al explores the impurity incorporation in (1-101) GaN grown on Si substrates. In the area of bulk crystal growth Kucharski et al review non- and semipolar GaN substrates by ammonothermal growth, and Chichibu et al discuss the challenges for epitaxial growth of InGaN on free-standing m-plane GaN substrates. Calculation of semipolar orientations for wurtzitic semiconductor heterostructures and their application to nitrides and oxides are reviewed by Bigenwald et al, and Ito et al present an ab initio approach to reconstruction, adsorption, and incorporation on GaN surfaces. Finally, the theoretical description of non-polar and semipolar nitride semiconductor quantum-well structures is presented by Ahn et al. In a discussion of the optical properties, Kisin et al discuss the effect of the quantum well population on the optical characteristics of polar, semipolar and non-polar III-nitride light emitters, and Jönen et al investigate the indium incorporation and optical properties of non- and semipolar GaInN QW structures. Wernicke et al explore the emission wavelength of polar, non-polar, and semipolar InGaN quantum wells and the incorporation of indium. In a contribution by Melo et al, the gain in polar and non-polar/semipolar gallium-nitride

  12. Raman scattering study of anharmonic phonon decay in InN

    NASA Astrophysics Data System (ADS)

    Domènech-Amador, Núria; Cuscó, Ramon; Artús, Luis; Yamaguchi, Tomohiro; Nanishi, Yasushi

    2011-06-01

    We present Raman scattering measurements on wurtzite InN over a temperature range from 80 to 660 K. To investigate all phonon modes of the wurtzite structure, measurements were performed on c and m faces of high-quality InN epilayers. High-resolution measurements of the low-frequency E2 mode reveal a slight anharmonic broadening of such a long-lived phonon due to up-conversion processes and a substantial contribution of background impurity broadening in the determination of its linewidth. An analysis of the anharmonicity and lifetimes of the InN phonons is carried out. Possible decay channels including up-conversion processes and four-phonon processes are discussed on the basis of density functional theory calculations.

  13. Terahertz detectors arrays based on orderly aligned InN nanowires

    PubMed Central

    Chen, Xuechen; Liu, Huiqiang; Li, Qiuguo; Chen, Hao; Peng, Rufang; Chu, Sheng; Cheng, Binbin

    2015-01-01

    Nanostructured terahertz detectors employing a single semiconducting nanowire or graphene sheet have recently generated considerable interest as an alternative to existing THz technologies, for their merit on the ease of fabrication and above-room-temperature operation. However, the lack of alignment in nanostructure device hindered their potential toward practical applications. The present work reports ordered terahertz detectors arrays based on neatly aligned InN nanowires. The InN nanostructures (nanowires and nano-necklaces) were achieved by chemical vapor deposition growth, and then InN nanowires were successfully transferred and aligned into micrometer-sized groups by a “transfer-printing” method. Field effect transistors on aligned nanowires were fabricated and tested for terahertz detection purpose. The detector showed good photoresponse as well as low noise level. Besides, dense arrays of such detectors were also fabricated, which rendered a peak responsivity of 1.1 V/W from 7 detectors connected in series. PMID:26289498

  14. Anomalous magnetism of superconducting Mg-doped InN film

    NASA Astrophysics Data System (ADS)

    Chang, P. H.; Hong, S. Y.; Lin, W. T.; Guo, Y. X.

    2016-02-01

    We report on the Meissner effect of Mg-doped InN film with superconducting transition onset temperature Tc,onset of 5 K. Mg-doped InN is magnetically ordered and exhibits a simultaneous first-order magnetic and electric transition near 50 K. Its behavior is similar to that of iron-based superconductors. A strong correlation is proposed to exist between structural distortion and superconductivity when Mg is doped into InN. The suppression of magnetic ordering close to Tc by doping is further demonstrated by anisotropic magnetoresistance and M-H measurements. The findings suggest that the superconducting mechanism in the system may not be conventional BCS.

  15. Terahertz detectors arrays based on orderly aligned InN nanowires

    NASA Astrophysics Data System (ADS)

    Chen, Xuechen; Liu, Huiqiang; Li, Qiuguo; Chen, Hao; Peng, Rufang; Chu, Sheng; Cheng, Binbin

    2015-08-01

    Nanostructured terahertz detectors employing a single semiconducting nanowire or graphene sheet have recently generated considerable interest as an alternative to existing THz technologies, for their merit on the ease of fabrication and above-room-temperature operation. However, the lack of alignment in nanostructure device hindered their potential toward practical applications. The present work reports ordered terahertz detectors arrays based on neatly aligned InN nanowires. The InN nanostructures (nanowires and nano-necklaces) were achieved by chemical vapor deposition growth, and then InN nanowires were successfully transferred and aligned into micrometer-sized groups by a “transfer-printing” method. Field effect transistors on aligned nanowires were fabricated and tested for terahertz detection purpose. The detector showed good photoresponse as well as low noise level. Besides, dense arrays of such detectors were also fabricated, which rendered a peak responsivity of 1.1 V/W from 7 detectors connected in series.

  16. Surface charge accumulation of InN films grown by molecular-beam epitaxy

    NASA Astrophysics Data System (ADS)

    Lu, Hai; Schaff, William J.; Eastman, Lester F.; Stutz, C. E.

    2003-03-01

    A series of thin InN films down to 10 nm in thickness were prepared by molecular-beam epitaxy on either AlN or GaN buffers under optimized growth conditions. By extrapolating the fitted curve of sheet carrier density versus film thickness to zero film thickness, a strong excess sheet charge was derived, which must come from either the surface or the interface between InN and its buffer layer. Since metal contacts, including Ti, Al, Ni, and a Hg probe, can always form an ohmic contact on InN without any annealing, it is determined that at least part of the excess charge is surface charge, which was also confirmed by capacitance-voltage measurements.

  17. Anomalous surface potential behavior observed in InN by photoassisted Kelvin probe force microscopy

    NASA Astrophysics Data System (ADS)

    Sun, Xiaoxiao; Wei, Jiandong; Wang, Xinqiang; Wang, Ping; Li, Shunfeng; Waag, Andreas; Li, Mo; Zhang, Jian; Ge, Weikun; Shen, Bo

    2017-05-01

    Lattice-polarity dependence of InN surface photovoltage has been identified by an anomalous surface potential behavior observed via photoassisted Kelvin probe force microscopy. Upon above bandgap light illumination in the ambient atmosphere, the surface photovoltage of the In-polar InN shows a pronounced decrease, while that of the N-polar one keeps almost constant. Those different behaviors between N-polar and In-polar surfaces are attributed to a polarity-related surface reactivity, which is found not to be influenced by Mg-doping. These findings provide a simple and non-destructive approach to determine the lattice polarity and allow us to suggest that the In-polar InN, especially that with buried p-type conduction, should be chosen for sensing application.

  18. Selective-Area Growth of Transferable InN Nanocolumns by Using Anodic Aluminum Oxide Nanotemplates.

    PubMed

    Wang, Xiao; Zhang, Guozhen; Xu, Yang; Wu, Hao; Liu, Chang

    2017-12-01

    InN nanocolumn arrays were grown on c-plane sapphire with and without anodic aluminum oxide (AAO) nanotemplates. The crystalline quality of InN nanocolumns was significantly improved by selective-area growth (SAG) using AAO templates, as verified by X-ray diffraction measurements. Then, InN nanocolumns were transferred onto p-type silicon substrates after etching off the AAO templates. Current-voltage characteristic of the transferred n-InN/p-Si heterojunctions shows on/off ratio as high as 4.65 × 10(3) at 2 V. This work offers a potential way to grow transferable devices with improving performances.

  19. Inhomogeneous free-electron distribution in InN nanowires: Photoluminescence excitation experiments

    NASA Astrophysics Data System (ADS)

    Segura-Ruiz, J.; Molina-Sánchez, A.; Garro, N.; García-Cristóbal, A.; Cantarero, A.; Iikawa, F.; Denker, C.; Malindretos, J.; Rizzi, A.

    2010-09-01

    Photoluminescence excitation (PLE) spectra have been measured for a set of self-assembled InN nanowires (NWs) and a high-crystalline quality InN layer grown by molecular-beam epitaxy. The PLE experimental lineshapes have been reproduced by a self-consistent calculation of the absorption in a cylindrical InN NW. The differences in the PLE spectra can be accounted for the inhomogeneous electron distribution within the NWs caused by a bulk donor concentration (ND+) and a two-dimensional density of ionized surface states (Nss+) . For NW radii larger than 30 nm, ND+ and Nss+ modify the absorption edge and the lineshape, respectively, and can be determined from the comparison with the experimental data.

  20. Hydrogen adsorbed at N-polar InN: Significant changes in the surface electronic properties

    NASA Astrophysics Data System (ADS)

    Eisenhardt, A.; Krischok, S.; Himmerlich, M.

    2015-06-01

    The interaction of atomic hydrogen and ammonia with as-grown N-polar InN surfaces is investigated using in situ photoelectron spectroscopy. Changes in the surface electronic properties, including the band alignment and work function, as well as the chemical bonding states of the substrate and adsorbates are characterized. Ammonia molecules are dissociating at the InN surface, resulting in adsorption of hydrogen species. Consequently, the considerable changes of the chemical and electronic properties of the InN surface during ammonia interaction are almost identical to those found for adsorption of atomic hydrogen. In both cases, hydrogen atoms preferentially bond to surface nitrogen atoms, resulting in the disappearance of the nitrogen dangling-bond-related occupied surface state close to the valence band edge at ˜1.6 eV binding energy and the formation of new occupied electron states at the conduction band edge. Furthermore, a decrease in work function during adsorption from 4.7 to 3.7-3.8 eV, as well as an increase in the surface downward band bending by 0.3 eV, confirm that hydrogen is acting as electron donor at InN surfaces and therefore has to be considered as one main reason for the surface electron accumulation observed at N-polar InN samples exposed to ambient conditions, for example as the dissociation product of molecules. The measured formation and occupation of electronic states above the conduction band minimum occur in conjunction with the observed increase in surface electron concentration and underline the relationship between the energy position of occupied electron states and surface band alignment for InN as a small-band-gap semiconductor.

  1. Nitride quantum light sources

    NASA Astrophysics Data System (ADS)

    Zhu, T.; Oliver, R. A.

    2016-02-01

    Prototype nitride quantum light sources, particularly single-photon emitters, have been successfully demonstrated, despite the challenges inherent in this complex materials system. The large band offsets available between different nitride alloys have allowed device operation at easily accessible temperatures. A wide range of approaches has been explored: not only self-assembled quantum dot growth but also lithographic methods for site-controlled nanostructure formation. All these approaches face common challenges, particularly strong background signals which contaminate the single-photon stream and excessive spectral diffusion of the quantum dot emission wavelength. If these challenges can be successfully overcome, then ongoing rapid progress in the conventional III-V semiconductors provides a roadmap for future progress in the nitrides.

  2. Nitrided Metallic Bipolar Plates

    SciTech Connect

    Brady, Michael P; Tortorelli, Peter F; Pihl, Josh A; Toops, Todd J; More, Karren Leslie; Meyer III, Harry M; Vitek, John Michael; Wang, Heli; Turner, John; Wilson, Mahlon; Garzon, Fernando; Rockward, Tommy; Connors, Dan; Rakowski, Jim; Gervasio, Don

    2008-01-01

    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.

  3. Two-dimensional electron gas in monolayer InN quantum wells

    DOE PAGES

    Pan, Wei; Dimakis, Emmanouil; Wang, George T.; ...

    2014-11-24

    We report in this letter experimental results that confirm the two-dimensional nature of the electron systems in monolayer InN quantum wells embedded in GaN barriers. The electron density and mobility of the two-dimensional electron system (2DES) in these InN quantum wells are 5×1015 cm-2 and 420 cm2 /Vs, respectively. Moreover, the diagonal resistance of the 2DES shows virtually no temperature dependence in a wide temperature range, indicating the topological nature of the 2DES.

  4. Two-dimensional electron gas in monolayer InN quantum wells

    SciTech Connect

    Pan, Wei; Dimakis, Emmanouil; Wang, George T.; Moustakas, Theodore D.; Tsui, Daniel C.

    2014-11-24

    We report in this letter experimental results that confirm the two-dimensional nature of the electron systems in monolayer InN quantum wells embedded in GaN barriers. The electron density and mobility of the two-dimensional electron system (2DES) in these InN quantum wells are 5×1015 cm-2 and 420 cm2 /Vs, respectively. Moreover, the diagonal resistance of the 2DES shows virtually no temperature dependence in a wide temperature range, indicating the topological nature of the 2DES.

  5. Sulfur passivation of surface electrons in highly Mg-doped InN

    NASA Astrophysics Data System (ADS)

    Linhart, W. M.; Chai, J.; McConville, C. F.; Durbin, S. M.; Veal, T. D.

    2013-09-01

    Electron accumulation with a sheet density greater than 1013 cm-2 usually occurs at InN surfaces. Here, the effects of treatment with ammonium sulfide ((NH4)2Sx) on the surface electronic properties of highly Mg-doped InN (>4×1018 cm-3) have been investigated with high resolution x-ray photoemission spectroscopy. The valence band photoemission spectra show that the surface Fermi level decreases by approximately 0.08 eV with (NH4)2Sx treatment, resulting in a decrease of the downward band bending and up to a 70% reduction in the surface electron sheet density.

  6. Microstructures of InN film on 4H-SiC (0001) substrate grown by RF-MBE

    NASA Astrophysics Data System (ADS)

    Jantawongrit, P.; Sanorpim, S.; Yaguchi, H.; Orihara, M.; Limsuwan, P.

    2015-08-01

    InN film was grown on 4H-SiC (0001) substrate by RF plasma-assisted molecular beam epitaxy (RF-MBE). Prior to the growth of InN film, an InN buffer layer with a thickness of ∼5.5 nm was grown on the substrate. Surface morphology, microstructure and structural quality of InN film were investigated. Micro-structural defects, such as stacking faults and anti-phase domain in InN film were carefully investigated using transmission electron microscopy (TEM). The results show that a high density of line contrasts, parallel to the growth direction (c-axis), was clearly observed in the grown InN film. Dark field TEM images recorded with diffraction vectors g=11\\bar{2}0 and g = 0002 revealed that such line contrasts evolved from a coalescence of the adjacent misoriented islands during the initial stage of the InN nucleation on the substrate surface. This InN nucleation also led to a generation of anti-phase domains. Project supported by the Thailand Center of Excellence in Physics (ThEP) and the King Mongkut's University of Technology Thonburi under The National Research University Project. One of the authors (S. Sanorpim) was supported by the National Research Council of Thailand (NRCT) and the Thai Government Stimulus Package 2 (TKK2555), under the Project for Establishment of Comprehensive Center for Innovative Food, Health Products and Agriculture.

  7. Study of InN epitaxial films and nanorods grown on GaN template by RF-MOMBE

    PubMed Central

    2012-01-01

    This paper reports on high-quality InN materials prepared on a GaN template using radio-frequency metalorganic molecular beam epitaxy. We also discuss the structural and electro-optical properties of InN nanorods/films. The X-ray diffraction peaks of InN(0002) and InN(0004) were identified from their spectra, indicating that the (0001)-oriented hexagonal InN was epitaxially grown on the GaN template. Scanning electron microscopic images of the surface morphology revealed a two-dimensional growth at a rate of approximately 0.85 μm/h. Cross-sectional transmission electron microscopy images identified a sharp InN/GaN interface and a clear epitaxial orientation relationship of [0001]InN // [0001]GaN and ( 2¯110)InN // ( 2¯110)GaN. The optical properties of wurtzite InN nanorods were determined according to the photoluminescence, revealing a band gap of 0.77 eV. PMID:22908859

  8. CONDENSED MATTER: STRUCTURE, MECHANICAL AND THERMAL PROPERTIES: Tetragonal Distortion of InN Thin Films by RBS/Channeling

    NASA Astrophysics Data System (ADS)

    Ding, Zhi-Bo; Wu, Wei; Wang, Kun; Fa, Tao; Yao, Shu-De

    2009-08-01

    Rutherford backscattering and channeling spectrometry (RBS/C) are used to identify the crystalline quality (χ min = 4.87%) of an InN thin film as a function of depth, and make a non-destructive quantitative analysis of the structure, in order to analyze the tetragonal distortion of the InN thin film at the depth determined.

  9. Cubic nitride templates

    DOEpatents

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

    2013-04-30

    A polymer-assisted deposition process for deposition of epitaxial cubic metal nitride films and the like is presented. The process includes solutions of one or more metal precursor and soluble polymers having binding properties for the one or more metal precursor. After a coating operation, the resultant coating is heated at high temperatures under a suitable atmosphere to yield metal nitride films and the like. Such films can be used as templates for the development of high quality cubic GaN based electronic devices.

  10. Indium Phosphide Window Layers for Indium Gallium Arsenide Solar Cells

    NASA Technical Reports Server (NTRS)

    Jain, Raj K.

    2005-01-01

    Window layers help in reducing the surface recombination at the emitter surface of the solar cells resulting in significant improvement in energy conversion efficiency. Indium gallium arsenide (In(x)Ga(1-x)As) and related materials based solar cells are quite promising for photovoltaic and thermophotovoltaic applications. The flexibility of the change in the bandgap energy and the growth of InGaAs on different substrates make this material very attractive for multi-bandgap energy, multi-junction solar cell approaches. The high efficiency and better radiation performance of the solar cell structures based on InGaAs make them suitable for space power applications. This work investigates the suitability of indium phosphide (InP) window layers for lattice-matched In(0.53)Ga(0.47)As (bandgap energy 0.74 eV) solar cells. We present the first data on the effects of the p-type InP window layer on p-on-n lattice-matched InGaAs solar cells. The modeled quantum efficiency results show a significant improvement in the blue region with the InP window. The bare InGaAs solar cell performance suffers due to high surface recombination velocity (10(exp 7) cm/s). The large band discontinuity at the InP/InGaAs heterojunction offers a great potential barrier to minority carriers. The calculated results demonstrate that the InP window layer effectively passivates the solar cell front surface, hence resulting in reduced surface recombination and therefore, significantly improving the performance of the InGaAs solar cell.

  11. Nitriding of restored crankshafts

    NASA Astrophysics Data System (ADS)

    Ponukalin, V. V.; Aleksandrov, V. N.

    1984-02-01

    The following technology is recommended for restoration of steel crankshafts: facing with an Sv-08 electrode wire under an AN-348A flux with chromium and niobium introduced into the melt in accordance with the method used at automotive-repair plants and subsequent gas nitriding at (570±10)°C for 12 h.

  12. Morphology and composition controlled growth of polar c-axis and nonpolar m-axis well-aligned ternary III-nitride nanotube arrays.

    PubMed

    Li, Huijie; Zhao, Guijuan; Kong, Susu; Han, Dongyue; Wei, Hongyuan; Wang, Lianshan; Chen, Zhen; Yang, Shaoyan

    2015-10-21

    Control over the nanostructure morphology and growth orientation is in high demand for fundamental research and technological applications. Herein we report a general strategy to fabricate polar c-axis and nonpolar m-axis well-aligned III-nitride ternary nanotube arrays with controllable morphologies and compositions. By depositing AlN on the InN nanorod array templates and thermally removing the InN templates, InAlN nanotubes can be obtained. Polar c-axis and nonpolar m-axis nanotubes were formed on the c- and r-plane sapphire substrates, respectively. The nanotubes are single crystalline and highly ordered on the substrates, as revealed by X-ray diffraction, electron microscopy, and selected area electron microscopy characterization. It was found that the In droplets on top of the InN nanorods play a critical role in controlling the morphology of the nanotubes. By keeping or removing the In droplets, the obtained nanotubes exhibited both ends open or only one end open. And by varying the AlN deposition temperature, the In composition in the nanotubes can be changed from 0 to 0.29. The nanotube synthesis method is simple and can be applied to the formation of other III-nitride ternary (InGaN, and AlGaN) or quaternary (InAlGaN) alloy nanotube arrays.

  13. Nitride heterostructure optimization by simulation

    NASA Astrophysics Data System (ADS)

    Rabinovich, O. I.; Legotin, S. A.; Didenko, S. I.

    2017-06-01

    In current paper nanoheterostructure optimization for LED and phototransistor usage is discussed. Special doping into quantum wells and barriers by Indium atoms was investigated. By simulation improved quantum sized active region was detected which increases quantum efficiency and sensitivity upto 10%. Photoluminescence spectral curve and Peak lambda of the InGaN/GaN nanoheterostructure with different Indium concentration across wafer were investigated.

  14. Golf Tournament Drives in a Win for the Children’s Inn | Poster

    Cancer.gov

    By Carolynne Keenan, Contributing Writer On September 23, golfers took to the Clustered Spires golf course in Frederick, Md., for a cause. The R&W Club Frederick hosted its inaugural golf tournament, with proceeds benefiting the National Institutes of Health (NIH) Children’s Inn.

  15. Self-assembled InN micro-mushrooms by upside-down pendeoepitaxy

    NASA Astrophysics Data System (ADS)

    Sarwar, A. T. M. Golam; Yang, Fan; Esser, Bryan D.; Kent, Thomas F.; McComb, David W.; Myers, Roberto C.

    2016-06-01

    Self-assembly of hexagonal InN micro-mushrooms on Si (111) substrates by molecular beam epitaxy is reported. Scanning electron microscopy (SEM) reveals hexagonal mushroom caps with smooth top surfaces and a step-like morphology at the bottom surface. A detailed growth study along with SEM measurements reveals that an upside-down pendeoepitaxy mechanism underlies the formation of these structures. Cryogenic temperature photoluminescence measurements on the InN disks show a dominant band-to-acceptor recombination peak at 0.68 eV. Cross-section annular bright field (ABF-) scanning transmission electron microscopy (STEM) reveals that the growth of these structures occurs along the [ 000 1 bar ] crystallographic orientation (N-face). Plan-view high angle annular dark field (HAADF) STEM in the center of the micro-disks reveals a hexagonal lattice indicative of stacking faults. However, at the outskirt of the micro-disk, surprisingly, a honeycomb lattice is observed in plan view STEM indicating a perfect freestanding Wurtzite InN disk that is free of stacking faults. This result opens a pathway for realizing strain-free, freestanding InN substrates.

  16. Dopants and Defects in InN and InGaN Alloys

    SciTech Connect

    Walukiewicz, W.; Jones, R.E.; Li, S.X.; Yu, K.M.; Ager III, J.W.; Haller, E.E.; Lu, H.; Schaff, W.J.

    2005-04-01

    We have performed systematic studies of the effects of high-energy particle irradiation on the properties of InGaN alloys. In agreement with the amphoteric defect model, irradiation of InN produces donor-like defects. The electron concentration increases with increasing radiation dose and saturates at 4 x 10{sup 20} cm{sup -3} at very high doses. We find that the increase of the electron concentration causes a large blue-shift of the absorption edge, which is well-explained by the Burstein-Moss effect. The maximum electron concentration decreases with increasing Ga fraction in irradiated In{sub 1-x}Ga{sub x}N alloys as the conduction band edge approaches the Fermi level stabilization energy (E{sub FS}). For x > 0.66 the conduction band edge moves above E{sub FS} and the irradiation of n-type films produces acceptor-like defects, resulting in a reduced free electron concentration. An analysis of the concentration dependence of the electron mobility in InN indicates that the dominant defects in irradiated InN are triply-charged donors. Finally, we show that InN films doped with Mg acceptors behave like undoped films above a threshold radiation dose.

  17. Golf Tournament Drives in a Win for the Children’s Inn | Poster

    Cancer.gov

    By Carolynne Keenan, Contributing Writer On September 23, golfers took to the Clustered Spires golf course in Frederick, Md., for a cause. The R&W Club Frederick hosted its inaugural golf tournament, with proceeds benefiting the National Institutes of Health (NIH) Children’s Inn.

  18. Mineral resource of the month: indium

    USGS Publications Warehouse

    Tolcin, Amy C.

    2011-01-01

    Geologically, the occurrence of indium minerals is rare. The element most often occurs as a sulfide inclusion or substitutes in other base-metal minerals, including cassiterite, chalcopyrite, sphalerite and stannite. Indium’s abundance in the crust is estimated to be 0.05 parts per million, which makes it more abundant than silver, but it is so widely disseminated that it does not occur in high enough concentrations to form mineable deposits. Therefore, indium is most often recovered from byproduct residues produced during the refining of lead and zinc. But only about one-quarter of the indium mined worldwide is refined into metal, as many indium-bearing concentrates are sent to refineries that do not have the capability of recovering the metal.

  19. Nanostructural and electronic properties of polytypes in InN nanocolumns

    SciTech Connect

    Kioseoglou, J.; Koukoula, T.; Komninou, Ph.; Kehagias, Th.; Georgakilas, A.; Androulidaki, M.

    2013-08-21

    Transmission electron microscopy techniques and density functional theory calculations were employed to investigate the nanostructural and electronic properties of InN polytypes observed in InN nanocolumns, grown on Si(111) by molecular beam epitaxy. Moiré fringes and alternating hexagonal and cubic lattice stacking sequences along the c-axis, observed among the wurtzite layers, implied the presence of different structures embedded in the basic 2H structure of the nanocolumns. Quantitative electron diffraction analysis and high-resolution image simulations verified the coexistence of the wurtzite structure with the 4H, 6H, and the 3C zinc-blende structural polytypes. Total energies calculations established the 2H wurtzite structure as the most stable polytype. The band gap of all polytypes was found direct with the energies and the band gaps of the 4H (E{sub g} = 0.64 eV) and 6H (E{sub g} = 0.60 eV) structures calculated between the corresponding values of the 2H (E{sub g} = 0.75 eV) and 3C (E{sub g} = 0.49 eV) basic structures. Theoretical and experimental analysis showed that at the initial stages of growth InN nanocolumns were under tensile strain along both the basal plane and growth direction. Structural polytypes were then introduced in the form of embedded inclusions to accommodate the excess tensile strain along the growth direction, allowing the entire process of polymorphism to be the dominant strain relaxation mechanism of InN nanocolumns. Moreover, the lattice and energetic properties and band gap values of InN polytypes showed a linear dependence on hexagonality, while the presence of polytypes led to a characteristic broadening of the photoluminescence emission peak toward lower emission energies.

  20. Study on the synthesis of Indium Tinoxide (ITO) nanomaterial using sol gel process and its potential for CO gas detection

    NASA Astrophysics Data System (ADS)

    Wiranto, Goib; Idayanti, Novrita; Retnaningsih, Lilis

    2016-11-01

    This paper described the synthesis of doped and undoped nanomaterial Indium Tinoxide (ITO) using sol-gel process with the base materials from Indium Nitride (In(NO3)) and Tin Chloride (SnCl4). Doping was done using Palladium Chloride (PdCl), with the molar ratio of 90:10 and 70:30, respectively. Physical characteristics of the nanocrystallites were examined using SEM, EDS, XRD, and FTIR, whereas its resistivity was tested agaist CO gas. The result showed that the ITO powders have a crystal size smaller than 100 nm, with a cubic crystal structure (byxbite type), and having strong molecular bonds for In-O-In and Sn-O-Sn. The response to CO gases showed a decreasing resistivity with increasing CO gas concentration, showing its potential for gas sensor application.

  1. Quantification of indium in steel using PIXE

    NASA Astrophysics Data System (ADS)

    Oliver, A.; Miranda, J.; Rickards, J.; Cheang, J. C.

    1989-04-01

    The quantitative analysis of steel for endodontics tools was carried out using low-energy protons (≤ 700 keV). A computer program for a thick-target analysis which includes enhancement due to secondary fluorescence was used. In this experiment the L-lines of indium are enhanced due to the proximity of other elements' K-lines to the indium absorption edge. The results show that the ionization cross section expression employed to evaluate this magnitude is important.

  2. Pressure-induced decomposition of indium hydroxide.

    PubMed

    Gurlo, Aleksander; Dzivenko, Dmytro; Andrade, Miria; Riedel, Ralf; Lauterbach, Stefan; Kleebe, Hans-Joachim

    2010-09-15

    A static pressure-induced decomposition of indium hydroxide into metallic indium that takes place at ambient temperature is reported. The lattice parameter of c-In(OH)(3) decreased upon compression from 7.977(2) to approximately 7.45 A at 34 GPa, corresponding to a decrease in specific volume of approximately 18%. Fitting the second-order Birch-Murnaghan equation of state to the obtained compression data gave a bulk modulus of 99 +/- 3 GPa for c-In(OH)(3). The c-In(OH)(3) crystals with a size of approximately 100 nm are comminuted upon compression, as indicated by the grain-size reduction reflected in broadening of the diffraction reflections and the appearance of smaller (approximately 5 nm) incoherently oriented domains in TEM. The rapid decompression of compressed c-In(OH)(3) leads to partial decomposition of indium hydroxide into metallic indium, mainly as a result of localized stress gradients caused by relaxation of the highly disordered indium sublattice in indium hydroxide. This partial decomposition of indium hydroxide into metallic indium is irreversible, as confirmed by angle-dispersive X-ray diffraction, transmission electron microscopy imaging, Raman scattering, and FTIR spectroscopy. Recovered c-In(OH)(3) samples become completely black and nontransparent and show typical features of metals, i.e., a falling absorption in the 100-250 cm(-1) region accompanied by a featureless spectrum in the 250-2500 cm(-1) region in the Raman spectrum and Drude-like absorption of free electrons in the region of 4000-8000 cm(-1) in the FTIR spectrum. These features were not observed in the initial c-In(OH)(3), which is a typical white wide-band-gap semiconductor.

  3. Indium Single-Ion Frequency Standard

    NASA Technical Reports Server (NTRS)

    Nagourney, Warren

    2001-01-01

    A single laser-cooled indium ion is a promising candidate for an ultimate resolution optical time or frequency standard. It can be shown that single ions from group IIIA of the periodic table (indium, thallium, etc.) can have extremely small systematic errors. In addition to being free from Doppler, transit-time and collisional shifts, these ions are also quite insensitive to perturbations from ambient magnetic and electric fields (mainly due to the use of a J=0-0 transition for spectroscopy). Of all group IIIA ions, indium seems to be the most practical, since it is heavy enough to have a tolerable intercombination cooling transition rate and (unlike thallium) has transitions which are easily accessible with frequency multiplied continuous-wave lasers. A single indium ion standard has a potential inaccuracy of one part in 10(exp 18) for integration times of 10(exp 6) seconds. We have made substantial progress during the grant period in constructing a frequency standard based upon a single indium ion. At the beginning of the grant period, single indium ions were being successfully trapped, but the lasers and optical systems were inadequate to achieve the desired goal. We have considerably improved the stability of the dye laser used to cool the ions and locked it to a molecular resonance line, making it possible to observe stable cooling-line fluorescence from a single indium ion for reasonable periods of time, as required by the demands of precision spectroscopy. We have substantially improved the single-ion fluorescence signal with significant benefits for the detection efficiency of forbidden transitions using the 'shelving' technique. Finally, we have constructed a compact, efficient UV 'clock' laser and observed 'clock' transitions in single indium ions using this laser system. We will elaborate on these accomplishments.

  4. High temperature surface degradation of III-V nitrides

    SciTech Connect

    Vartuli, C.B.; Pearton, S.J.; Abernathy, C.R.; MacKenzie, J.D.; Lambers, E.S.; Zolper, J.C.

    1996-05-01

    The surface stoichiometry, surface morphology and electrical conductivity of AlN, GaN, InN, InGaN and InAlN was examined at rapid thermal annealing temperatures up to 1,150 C. The sheet resistance of the AlN dropped steadily with annealing, but the surface showed signs of roughening only above 1,000 C. Auger Electronic Spectroscopy (AES) analysis showed little change in the surface stoichiometry even at 1,150 C. GaN root mean square (RMS) surface roughness showed an overall improvement with annealing, but the surface became pitted at 1,000 C, at which point the sheet resistance also dropped by several orders of magnitude, and AES confirmed a loss of N from the surface. The InN surface had roughened considerably even at 650 C, and scanning electron microscopy (SEM) showed significant degradation. In contrast to the binary nitrides the sheet resistance of InAlN was found to increase by {approximately} 10{sup 2} from the as grown value after annealing at 800 C and then remain constant up to 1,000 C, while that of InGaN increased rapidly above 700 C. The RMS roughness increased above 800 C and 700 C respectively for InAlN and InGaN samples. In droplets began to form on the surface at 900 C for InAlN and at 800 C for InGaN, and then evaporate at 1,000 C leaving pits. AES analysis showed a decrease in the N concentration in the top 500 {angstrom} of the sample for annealing {ge} 800 C in both materials.

  5. Analysis of plasma nitrided steels

    NASA Technical Reports Server (NTRS)

    Salik, J.; Ferrante, J.; Honecy, F.; Hoffman, R., Jr.

    1987-01-01

    The analysis of plasma nitrided steels can be divided to two main categories - structural and chemical. Structural analysis can provide information not only on the hardening mechanisms but also on the fundamental processes involved. Chemical analysis can be used to study the kinetics for the nitriding process and its mechanisms. In this paper preliminary results obtained by several techniques of both categories are presented and the applicability of those techniques to the analysis of plasma-nitrided steels is discussed.

  6. Pulsed laser nitriding of uranium

    NASA Astrophysics Data System (ADS)

    Zhang, Yongbin; Meng, Daqiao; Xu, Qinying; Zhang, Youshou

    2010-02-01

    Pulsed laser nitriding offers several advantages such as high nitrogen concentration, low matrix temperature, fast treatment, simple vacuum chamber and precise position control compare to ion implantation, which is favorable for radioactive material passivation. In this work, uranium metal was nitrided using an excimer laser for the first time. The nitrided layers are characterized by X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy. The nitride layer is composed mainly of UN and U 2N 3 and depends on nitriding process. The amount of nitride increases with energy density and pressure. The irradiated area has a wavy structure which increases the roughness, while scratches and asperities caused by sand paper polishing were eliminated. Scan speed has a profound influence on the nitride layer, at low speed U 2N 3 is more likely to form and the nitride layer tends to crack. XPS analysis shows that nitrogen has diffused into interior, while oxygen is only present on the surface. Ambient and humid-hot corrosion tests show the nitrided sample has good anticorrosion property.

  7. Irradiation performance of nitride fuels

    SciTech Connect

    Matthews, R.B.

    1993-01-01

    The properties and advantages of nitride fuels are well documented in the literature. Basically the high thermal conductivity and uranium density of nitride fuels permit high power density, good breeding ratios, low reactivity swings, and large diameter pins compared to oxides. Nitrides are compatible with cladding alloys and liquid metal coolants, thereby reducing fuel/cladding chemical interactions and permitting the use of sodium-bonded pins and the operation of breached pins. Recent analyses done under similar operating conditions show that - compared to metal - fuels mixed nitrides operate at lower temperatures, produce less cladding strain, have greater margins to failure, result in lower transient temperatures, and have lower sodium void reactivity. Uranium nitride fuel pellet fabrication processes were demonstrated during the SP-100 program, and irradiated nitride fuels can be reprocessed by the PUREX process. Irradiation performance data suggest that nitrides have low fission gas release and swelling rates thereby permitting favorable pin designs and long lifetime. The objective of this report is to summarize the available nitride irradiation performance data base and to recommend optimum nitride characteristics for use in advanced liquid metal reactors.

  8. Electrically injected near-infrared light emission from single InN nanowire p-i-n diode

    SciTech Connect

    Le, Binh Huy; Zhao, Songrui; Tran, Nhung Hong; Mi, Zetian

    2014-12-08

    We report on the achievement of electroluminescence emission of single InN p-i-n nanowire devices. InN p-i-n nanowire structures were grown directly on Si substrate by plasma-assisted molecular beam epitaxy and subsequently transferred to foreign substrate for the fabrication of single nanowire light emitting diodes. Electroluminescence emission with a peak energy of 0.71 eV (1.75 μm) was observed at 77 K. The measurement of near-bandgap electroluminescence provides unambiguous evidence for the achievement of p-type conduction of InN.

  9. Superplastic forging nitride ceramics

    DOEpatents

    Panda, Prakash C.; Seydel, Edgar R.; Raj, Rishi

    1988-03-22

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

  10. Boron nitride nanotubes.

    PubMed

    Chopra, N G; Luyken, R J; Cherrey, K; Crespi, V H; Cohen, M L; Louie, S G; Zettl, A

    1995-08-18

    The successful synthesis of pure boron nitride (BN) nanotubes is reported here. Multi-walled tubes with inner diameters on the order of 1 to 3 nanometers and with lengths up to 200 nanometers were produced in a carbon-free plasma discharge between a BN-packed tungsten rod and a cooled copper electrode. Electron energy-loss spectroscopy on individual tubes yielded B:N ratios of approximately 1, which is consistent with theoretical predictions of stable BN tube structures.

  11. Bulk Cubic Gallium Nitride

    DTIC Science & Technology

    1999-02-09

    microcrysta. form at bottom of «he reaction vessel. The objective of the second step is the solvothermal transport of the gallium nitride residing in the...system using pressure pumps can be used to gain precise control of the pressure. High pressure is typically used for the solvothermal transport. The...takes place in the reaction vessel during heating is a solvothermal reaction that is conducted at or above the critical point of the solvent The

  12. Extreme Band Engineering of III-Nitride Nanowire Heterostructures for Electronic and Photonic Application

    NASA Astrophysics Data System (ADS)

    Sarwar, ATM Golam

    Bottom-up nanowires are attractive for realizing semiconductor devices with extreme heterostructures because strain relaxation through the nanowire sidewalls allows the combination of highly lattice mismatched materials without creating dislocations. The resulting nanowires are used to fabricate light-emitting diodes (LEDs), lasers, solar cells, and sensors. The aim of this work is to investigate extreme heterostructures, which are impossible or very hard to realize in conventional planar films, exploiting the strain accommodation property of nanowires and engineer their band structure for novel electronic and photonic applications. To this end, in this thesis, III-Nitride semiconductor nanowires are investigated. In the first part of this work, a complete growth phase diagram of InN nanowires on silicon using plasma assisted molecular beam epitaxy is developed, and structural and optical characteristics are mapped as a function of growth parameters. Next, a novel up-side down pendeoepitaxial growth of InN forming mushroom-like microstructures is demonstrated and detail structural and optical characterizations are performed. Based on this, a method to grow strain-free large area single crystalline InN or thin film is proposed and the growth of InN on patterned GaN is investigated. The optimized growth conditions developed for InN are further used to grow InGaN nanowires graded over the whole composition range. Numerical energy band simulation is performed to better understand the effect of polarization charge on photo-carrier transport in these extremely graded nanowires. A novel photodetector device with negative differential photocurrent is demonstrated using the graded InGaN nanowires. In the second part of this thesis, polarization-induced nanowire light emitting diodes (PINLEDs) are investigated. The electrical and optical properties of the nanowire heterostructure are engineered and optimized for ultraviolet and deep ultraviolet applications. The electrical

  13. Gallium nitride electronics

    NASA Astrophysics Data System (ADS)

    Rajan, Siddharth; Jena, Debdeep

    2013-07-01

    In the past two decades, there has been increasing research and industrial activity in the area of gallium nitride (GaN) electronics, stimulated first by the successful demonstration of GaN LEDs. While the promise of wide band gap semiconductors for power electronics was recognized many years before this by one of the contributors to this issue (J Baliga), the success in the area of LEDs acted as a catalyst. It set the field of GaN electronics in motion, and today the technology is improving the performance of several applications including RF cell phone base stations and military radar. GaN could also play a very important role in reducing worldwide energy consumption by enabling high efficiency compact power converters operating at high voltages and lower frequencies. While GaN electronics is a rapidly evolving area with active research worldwide, this special issue provides an opportunity to capture some of the great advances that have been made in the last 15 years. The issue begins with a section on epitaxy and processing, followed by an overview of high-frequency HEMTs, which have been the most commercially successful application of III-nitride electronics to date. This is followed by review and research articles on power-switching transistors, which are currently of great interest to the III-nitride community. A section of this issue is devoted to the reliability of III-nitride devices, an area that is of increasing significance as the research focus has moved from not just high performance but also production-worthiness and long-term usage of these devices. Finally, a group of papers on new and relatively less studied ideas for III-nitride electronics, such as interband tunneling, heterojunction bipolar transistors, and high-temperature electronics is included. These areas point to new areas of research and technological innovation going beyond the state of the art into the future. We hope that the breadth and quality of articles in this issue will make it

  14. Short period strain balanced gallium arsenide nitride/indium arsenide nitride superlattice lattice matched to indium phosphide for mid-infrared photovoltaics

    NASA Astrophysics Data System (ADS)

    Bhusal, Lekhnath

    Dilute nitrogen-containing III-V-N alloys have been intensively studied for their unusual electronic and optical behavior in the presence of a small amount of nitrogen. Those behaviors can further be manipulated, with a careful consideration of the strain and strain balancing, for example, in the context of a strain-balanced superlattice (SL) based on those alloys. In this work, the k.p approximation and the band anti-crossing model modified for the strain have been used to describe the electronic states of the strained bulk-like GaAs1-xNx and InAs 1-yNy ternaries in the vicinity of the center of the Brillouin zone (Gamma-point). Band-offsets between the conduction and valence bands of GaAs1-xNx and InAs1-yN y have also been evaluated, before implementing them into the SL structure. By minimizing the total mechanical energy of the stack of the alternating layers of GaAs1-xNx and InAs1-yNy in the SL, the ratio of the thicknesses of the epilayers is determined to make the structure lattice-matching on the InP(001), through the strain-balancing. Mini-band energies of the strain-balanced GaAs1-xNx/InAs 1-yNy short-period SL on InP(001) is then investigated using the transfer matrix formalism. This enabled identifying the evolution of the band edge transition energies of the superlattice structure for different nitrogen compositions. Results show the potential of the new proposed design to exceed the existing limits of bulk-like InGaAsN alloys and offer the applications for photon absorption/emission energies in the range of ~0.65-0.35eV at 300K for a typical nitrogen composition of ≤5%. The optical absorption coefficient of such a SL is then estimated under the anisotropic medium approximation, where the optical absorption of the bulk structure is modified according to the anisotropy imposed by the periodic potential in the growth direction. As an application, the developed SL structure is used to investigate the performance of double, triple and quadruple junction thermophotovoltaic devices. Integration of the SL structure, which is lattice matched to InP, in the i region of the p(InGaAs)- i(SL) n(InGaAs) diode allowed the possibility of more than two junction thermophotovoltiac device with the enhanced performance in comparison to the conventional p(InGaAs)n(InGaAs) diode.

  15. 40 CFR 421.190 - Applicability: Description of the secondary indium subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... secondary indium subcategory. 421.190 Section 421.190 Protection of Environment ENVIRONMENTAL PROTECTION... CATEGORY Secondary Indium Subcategory § 421.190 Applicability: Description of the secondary indium... indium at secondary indium facilities processing spent electrolyte solutions and scrap indium metal raw...

  16. 40 CFR 421.190 - Applicability: Description of the secondary indium subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... secondary indium subcategory. 421.190 Section 421.190 Protection of Environment ENVIRONMENTAL PROTECTION... CATEGORY Secondary Indium Subcategory § 421.190 Applicability: Description of the secondary indium... indium at secondary indium facilities processing spent electrolyte solutions and scrap indium metal raw...

  17. 40 CFR 421.190 - Applicability: Description of the secondary indium subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... secondary indium subcategory. 421.190 Section 421.190 Protection of Environment ENVIRONMENTAL PROTECTION... CATEGORY Secondary Indium Subcategory § 421.190 Applicability: Description of the secondary indium... indium at secondary indium facilities processing spent electrolyte solutions and scrap indium metal raw...

  18. 40 CFR 421.190 - Applicability: Description of the secondary indium subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... secondary indium subcategory. 421.190 Section 421.190 Protection of Environment ENVIRONMENTAL PROTECTION... CATEGORY Secondary Indium Subcategory § 421.190 Applicability: Description of the secondary indium... indium at secondary indium facilities processing spent electrolyte solutions and scrap indium metal raw...

  19. 40 CFR 421.190 - Applicability: Description of the secondary indium subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... secondary indium subcategory. 421.190 Section 421.190 Protection of Environment ENVIRONMENTAL PROTECTION... CATEGORY Secondary Indium Subcategory § 421.190 Applicability: Description of the secondary indium... indium at secondary indium facilities processing spent electrolyte solutions and scrap indium metal raw...

  20. R&W Club Frederick Raises $1,500 for The Children’s Inn at Annual Golf Tournament | Poster

    Cancer.gov

    Forty-four government and contractor employees, along with their friends and family members, took to the Maryland National Golf Club course this fall for a cause. The R&W Club Frederick held its third annual golf tournament at the Middletown, Md., golf course on Sept. 14 to raise funds for The Children’s Inn at NIH, which celebrated its 25th anniversary this year. The Inn provides support and a home away from home for seriously ill children and their families receiving treatment at the NIH Clinical Center. Through the tournament, the club raised approximately $1,500 for The Children’s Inn, according to Tanya Ransom, biologist, NCI Center for Cancer Research, and secretary of the R&W Club Frederick. She also coordinated the golf tournament. After the tournament, a silent auction of sports memorabilia and collectibles, sponsored by Great Moments, Frederick, was held, and a portion of the proceeds also went to the Inn.

  1. R&W Club Frederick Raises $1,500 for The Children’s Inn at Annual Golf Tournament | Poster

    Cancer.gov

    Forty-four government and contractor employees, along with their friends and family members, took to the Maryland National Golf Club course this fall for a cause. The R&W Club Frederick held its third annual golf tournament at the Middletown, Md., golf course on Sept. 14 to raise funds for The Children’s Inn at NIH, which celebrated its 25th anniversary this year. The Inn provides support and a home away from home for seriously ill children and their families receiving treatment at the NIH Clinical Center. Through the tournament, the club raised approximately $1,500 for The Children’s Inn, according to Tanya Ransom, biologist, NCI Center for Cancer Research, and secretary of the R&W Club Frederick. She also coordinated the golf tournament. After the tournament, a silent auction of sports memorabilia and collectibles, sponsored by Great Moments, Frederick, was held, and a portion of the proceeds also went to the Inn.

  2. Epitaxial relationship of semipolar s-plane (1101) InN grown on r-plane sapphire

    SciTech Connect

    Dimitrakopulos, G. P.

    2012-07-02

    The heteroepitaxy of semipolar s-plane (1101) InN grown directly on r-plane sapphire by plasma-assisted molecular beam epitaxy is studied using transmission electron microscopy techniques. The epitaxial relationship is determined to be (1101){sub InN} Parallel-To (1102){sub Al{sub 2O{sub 3}}}, [1120]{sub InN} Parallel-To [2021]{sub Al{sub 2O{sub 3}}}, [1102]{sub InN}{approx} Parallel-To [0221]{sub Al{sub 2O{sub 3}}}, which ensures a 0.7% misfit along [1120]{sub InN}. Two orientation variants are identified. Proposed geometrical factors contributing to the high density of basal stacking faults, partial dislocations, and sphalerite cubic pockets include the misfit accommodation and reduction, as well as the accommodation of lattice twist.

  3. Electrochemical nitridation of metal surfaces

    DOEpatents

    Wang, Heli; Turner, John A.

    2015-06-30

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

  4. Platinum nitride with fluorite structure

    SciTech Connect

    Yu, Rong; Zhang, Xiao-Feng

    2005-01-31

    The mechanical stability of platinum nitride has been studied using first-principles calculations. By calculating the single-crystal elastic constants, we show that platinum nitride can be stabilized in the fluorite structure, in which the nitrogen atoms occupy all the tetrahedral interstitial sites of the metal lattice. The stability is attributed to the pseudogap effect from analysis of the electronic structure.

  5. Solar hot water system installed at Days Inn Motel, Dallas, Texas (Valley View)

    SciTech Connect

    1980-09-01

    The solar hot water system installed in the Days Inns of America, Inc., Days Inn Motel (120 rooms), I-35/2276 Valley View Lane, Dallas, Texas is described. The solar system was designed by ILI Incorporated to provide 65 percent of the total domestic hot water (DHW) demand. The Solar Energy Products, model CU-30WW liquid (water) flat plate collector (1000 square feet) system automatically drains into the 1000 gallon steel storage tank when the solar pump is not running. This system is one of eleven systems planned. Heat is transferred from the DHW tanks through a shell and tube heat exchanger. A circulating pump between the DHW tanks and heat exchanger enables solar heated water to help make up standby losses. All pumps are controlled by differential temperature controllers. The operation of this system was begun March 11, 1980. The solar components were partly funded ($15,000 of 30,000 cost) by a Department of Energy grant.

  6. Circular photogalvanic effect at inter-band excitation in InN

    NASA Astrophysics Data System (ADS)

    Zhang, Z.; Zhang, R.; Liu, B.; Xie, Z. L.; Xiu, X. Q.; Han, P.; Lu, H.; Zheng, Y. D.; Chen, Y. H.; Tang, C. G.; Wang, Z. G.

    2008-01-01

    The circular photogalvanic effect (CPGE) is observed in InN at inter-band excitation. The function of the CPGE induced current on laser helicity is experimentally demonstrated and illustrated with the microscopic model. A spin-dependent current obtained in InN is one order larger than in the AlGaN/GaN heterostructures at inter-band excitation. The dependence of CPGE current amplitude on light power and incident angle can be well evaluated with phenomenological theory. This sizeable spin-dependent current not only provides an opportunity to realize spin polarized current at room temperature, but also can be utilized as a reliable tool of spin splitting investigation in semiconductors.

  7. Reconstruction of an inn fire scene using the Fire Dynamics Simulator (FDS) program.

    PubMed

    Chi, Jen-Hao

    2013-01-01

    An inn fire occurring in the middle of the night usually causes a great deal more injuries and deaths. This article examines the case study of an inn fire accident that resulted in the most serious casualties in Taiwan's history. Data based on the official fire investigation report and NFPA921 regulations are used, and the fire scenes are reconstructed using the latest Fire Dynamics Simulator (FDS) program from NIST. The personnel evacuation time and time variants for various fire hazard factors of reconstructive analysis clarify the reason for such a high number of casualties. It reveals that the FDS program has come to play an essential role in fire investigation. The close comparison between simulation result and the actual fire scene also provides fire prevention engineers, a possible utilization of FDS to examine the effects of improved schemes for fire safety of buildings.

  8. Morphology Controlled Fabrication of InN Nanowires on Brass Substrates

    PubMed Central

    Li, Huijie; Zhao, Guijuan; Wang, Lianshan; Chen, Zhen; Yang, Shaoyan

    2016-01-01

    Growth of semiconductor nanowires on cheap metal substrates could pave the way to the large-scale manufacture of low-cost nanowire-based devices. In this work, we demonstrated that high density InN nanowires can be directly grown on brass substrates by metal-organic chemical vapor deposition. It was found that Zn from the brass substrates is the key factor in the formation of nanowires by restricting the lateral growth of InN. The nanowire morphology is highly dependent on the growth temperature. While at a lower growth temperature, the nanowires and the In droplets have large diameters. At the elevated growth temperature, the lateral sizes of the nanowires and the In droplets are much smaller. Moreover, the nanowire diameter can be controlled in situ by varying the temperature in the growth process. This method is very instructive to the diameter-controlled growth of nanowires of other materials. PMID:28335323

  9. Conservation of the Sinclair Inn Museum, and the Painted Room Annapolis Royal, Nova Scotia, Canada

    NASA Astrophysics Data System (ADS)

    Shaftel, A.; Ward, J.

    2017-08-01

    Conservation of the historic 18thC. Sinclair Inn Museum, and of the recently discovered late 18th/early 19thC. unique panoramic wall paintings located in an upstairs room, are co-dependent. This project was carried out with Canadian Conservation Institute (CCI) staff, and Conservator in Private Practice Ann Shaftel. This paper will introduce the Sinclair Inn Museum, outline the CCI murals and building investigations of 2011-15, the mural investigation of 2015-16, which confirmed that the mural extended to all four walls of the function room, now referred to as the Painted Room, and to describe how it has been revealed and conserved to date.

  10. Nitrogen ion beam synthesis of InN in InP(100) at elevated temperature

    SciTech Connect

    Dhara, S.; Magudapathy, P.; Kesavamoorthy, R.; Kalavathi, S.; Sastry, V.S.; Nair, K.G.M.; Hsu, G.M.; Chen, L.C.; Chen, K.H.; Santhakumar, K.; Soga, T.

    2006-06-12

    The InN phase is grown in crystalline InP(100) substrates by 50 keV N{sup +} implantation at an elevated temperature of 400 deg. C followed by annealing at 525 deg. C in N{sub 2} ambient. Crystallographic structural and Raman scattering studies are performed for the characterization of grown phases. Temperature- and power-dependent photoluminescence studies show direct band-to-band transition peak {approx}1.06 eV at temperatures {<=}150 K. Implantations at an elevated temperature with a low ion beam current and subsequent low temperature annealing step are found responsible for the growth of high-quality InN phase.

  11. Thermal Stability of Chelated Indium Activable Tracers

    SciTech Connect

    Chrysikopoulos, Costas; Kruger, Paul

    1986-01-21

    The thermal stability of indium tracer chelated with organic ligands ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA) was measured for reservoir temperatures of 150, 200, and 240 C. Measurements of the soluble indium concentration was made as a function of time by neutron activation analysis. From the data, approximate thermal decomposition rates were estimated. At 150 C, both chelated tracers were stable over the experimental period of 20 days. At 200 C, the InEDTA concentration remained constant for 16 days, after which the thermal decomposition occurred at a measured rate constant of k = 0.09 d{sup -1}. The thermal decomposition of InNTA at 200 C showed a first order reaction with a measured rate constant of k = 0.16 d{sup -1}. At 240 C, both indium chelated tracers showed rapid decomposition with rate constants greater than 1.8 d{sup -1}. The data indicate that for geothermal reservoir with temperatures up to about 200 C, indium chelated tracers can be used effectively for transit times of at least 20 days. These experiments were run without reservoir rock media, and do not account for concomitant loss of indium tracer by adsorption processes.

  12. Indium adhesion provides quantitative measure of surface cleanliness

    NASA Technical Reports Server (NTRS)

    Krieger, G. L.; Wilson, G. J.

    1968-01-01

    Indium tipped probe measures hydrophobic and hydrophilic contaminants on rough and smooth surfaces. The force needed to pull the indium tip, which adheres to a clean surface, away from the surface provides a quantitative measure of cleanliness.

  13. Indium: bringing liquid-crystal displays into focus

    USGS Publications Warehouse

    Mercer, Celestine N.

    2015-07-30

    Compared to more abundant industrial metals such as lead and zinc, information about the behavior and toxicity of indium in the environment is limited. However, many indium compounds have been proven to be toxic to animals.

  14. Indium oxide/n-silicon heterojunction solar cells

    DOEpatents

    Feng, Tom; Ghosh, Amal K.

    1982-12-28

    A high photo-conversion efficiency indium oxide/n-silicon heterojunction solar cell is spray deposited from a solution containing indium trichloride. The solar cell exhibits an Air Mass One solar conversion efficiency in excess of about 10%.

  15. Powder-XRD and (14) N magic angle-spinning solid-state NMR spectroscopy of some metal nitrides.

    PubMed

    Kempgens, Pierre; Britton, Jonathan

    2016-05-01

    Some metal nitrides (TiN, ZrN, InN, GaN, Ca3 N2 , Mg3 N2 , and Ge3 N4 ) have been studied by powder X-ray diffraction (XRD) and (14) N magic angle-spinning (MAS) solid-state NMR spectroscopy. For Ca3 N2 , Mg3 N2 , and Ge3 N4 , no (14) N NMR signal was observed. Low speed (νr  = 2 kHz for TiN, ZrN, and GaN; νr  = 1 kHz for InN) and 'high speed' (νr  = 15 kHz for TiN; νr  = 5 kHz for ZrN; νr  = 10 kHz for InN and GaN) MAS NMR experiments were performed. For TiN, ZrN, InN, and GaN, powder-XRD was used to identify the phases present in each sample. The number of peaks observed for each sample in their (14) N MAS solid-state NMR spectrum matches perfectly well with the number of nitrogen-containing phases identified by powder-XRD. The (14) N MAS solid-state NMR spectra are symmetric and dominated by the quadrupolar interaction. The envelopes of the spinning sidebands manifold are Lorentzian, and it is concluded that there is a distribution of the quadrupolar coupling constants Qcc 's arising from structural defects in the compounds studied.

  16. Epitaxial growth, electrical and optical properties of a-plane InN on r-plane sapphire

    SciTech Connect

    Ajagunna, A. O.; Iliopoulos, E.; Tsiakatouras, G.; Tsagaraki, K.; Androulidaki, M.; Georgakilas, A.

    2010-01-15

    The heteroepitaxy of a-plane (1120) InN films on r-plane (1102) sapphire substrates, by nitrogen radio frequency plasma-assisted molecular beam epitaxy, has been investigated and compared to that of c-plane (0001) InN. The epitaxial growth of a-plane InN proceeded through the nucleation, growth, and coalescence of three-dimensional islands, resulting in surface roughness that increased monotonically with epilayer thickness. The full width at half maximum of (1120) x-ray diffraction rocking curves decreased significantly with increasing InN thickness, characteristic of structural improvement, and it reached the value of 24 arcmin for a 1 {mu}m thick film. Hall-effect measurements exhibited a similar dependence of electron concentration and mobility on thickness for both the a- and c-plane InN films. The analysis of the Hall-effect measurements, by considering the contribution of two conducting layers, indicates a similar accumulation of low mobility electrons with N{sub s}>10{sup 14} cm{sup -2} at the films' surface/interfacial region for both the a- and c-plane InN films. From optical transmittance measurements, the absorption edge of 0.768 eV was determined for the 1 {mu}m a-plane film, consistent with the expected Burstein-Moss effect. Photoluminescence spectra exhibited a lower energy peak at 0.631 eV, suggesting defect-related transitions.

  17. First principles study of effects of vacancies on electronic, magnetic and optical properties of InN nanosheet

    NASA Astrophysics Data System (ADS)

    Farzan, M.; Elahi, S. M.; Abolhassani, M. R.; Salehi, H.

    2017-05-01

    Based on the first principle study within the generalized gradient approximation (GGA) in the density functional theory (DFT) implemented in Wien2k code, the effects of vacancies on electronic, magnetic and optical properties of InN nanosheet were investigated. We found that the vacancies in InN nanosheet induce spin polarized states in the band gap, and VN-defect, VIn-defect and VIn&N-defect induce local magnetic moments of (-0.01)μB , 3.0μB and 2.0μB , respectively. Also, we calculated the dielectric function, refraction index, extinction index, reflectivity, absorption coefficient, optical conductivity and energy loss function of the perfect InN nanosheet and VN-defect, VIn-defect and VIn&N-defect of InN nanosheet for both polarization directions of light, i.e. E||x (electric field parallel to nanosheet) and E||z (electric field perpendicular to nanosheet). Our results show that InN nanosheet is a semiconductor which is dependent on the type of vacancies and that the optical properties of perfect and defective InN nanosheets are anisotropic for both polarization states.

  18. Assessment of workplace air concentrations of indium dust in an indium-recycling plant.

    PubMed

    Miyauchi, Hiroyuki; Minozoe, Aoi; Tanaka, Shigeru; Tanaka, Akiyo; Hirata, Miyuki; Nakaza, Masahiro; Arito, Heihachiro; Eitaki, Yoko; Nakano, Makiko; Omae, Kazuyuki

    2012-01-01

    Suspended indium dust in an indium-recycling plant was quantified, in order to improve the work environment and to reduce workers' exposure to the dust. Assessment of indium dust in the workplace air by multipoint area sampling and personal breathing zone sampling was conducted twice in 2004 and 2008. In 2004, all recycling processes except for purity analysis were classified into control class III according to the 2004 Notification. Two out of 5 workers were exposed to total dust with indium concentrations exceeding the ACGIH's TLV-TWA of 0.1 mg In/m(3). In 2008, the indium-contaminated workplace air was improved by local exhaust ventilation systems installed in some processes, resulting in control class I. According to the 2010 Technical Guideline, however, all the processes were classified into stage II or III, indicating that the first assessment value or Measurement B-based concentrations exceeded the acceptable exposure concentration limit of 0.0003 mg In/m(3) of respirabe dust. Exposure of almost all the workers to indium dust was below the TLV-TWA. The first field survey showed that almost all workplaces were classified into control class III, and that some workers were exposed to dust with indium concentrations exceeding the TLV-TWA. It was found in the second survey that workplace air contamination was improved by the local exhaust ventilation system, but was not reduced sufficiently to a level that meets the new Guideline.

  19. Photoelectrochemical properties of InN nanowire photoelectrodes for solar water splitting

    NASA Astrophysics Data System (ADS)

    Kamimura, J.; Bogdanoff, P.; Ramsteiner, M.; Geelhaar, L.; Riechert, H.

    2016-07-01

    InN nanowires were grown on Si(111) substrates by plasma-assisted molecular beam epitaxy. Raman spectroscopy showed that the nanowires were strain-free and allowed the deduction of a free carrier concentration of 1-2 × 1018 cm-3. This value was confirmed by a Mott-Schottky analysis of electrolyte-based capacitance-voltage measurements. In addition, these measurements directly revealed the existence of a surface accumulation layer in the InN nanowires. In cyclic voltammetry measurements under irradiation from a Xe lamp with about 100 mW cm-2, high photocurrents of about 4 and 11 mA cm-2 were observed at 1.23 and 1.63 V bias potential versus reversible hydrogen electrode, respectively, using H2O2 as a hole scavenger. By comparing the photocurrent with and without H2O2, the main limiting factor in the performance of InN nanowire photoanodes was identified to be the poor catalytic efficiency for water oxidation at the surface, followed by parasitic bulk recombination.

  20. Synthesis and characterization of actinide nitrides

    SciTech Connect

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

    2007-07-01

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

  1. Indium-111 leukocyte scanning and fracture healing

    SciTech Connect

    Mead, L.P.; Scott, A.C.; Bondurant, F.J.; Browner, B.D. )

    1990-01-01

    This study was undertaken to determine the specificity of indium-111 leukocyte scans for osteomyelitis when fractures are present. Midshaft tibial osteotomies were performed in 14 New Zealand white rabbits, seven of which were infected postoperatively with Staphylococcus aureus per Norden's protocol. All 14 rabbits were scanned following injection with 75 microCi of indium 111 at 72 h after osteotomy and at weekly intervals for 4 weeks. Before the rabbits were killed, the fracture sites were cultured to document the presence or absence of infection. The results of all infected osteotomy sites were positive, whereas no positive scans were found in the noninfected osteotomies. We concluded from this study that uncomplicated fracture healing does not result in a positive indium-111 leukocyte scan.

  2. 40 CFR 721.10391 - Copper gallium indium selenide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Copper gallium indium selenide. 721... Substances § 721.10391 Copper gallium indium selenide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as copper gallium indium selenide (PMN P-10...

  3. 40 CFR 721.10391 - Copper gallium indium selenide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Copper gallium indium selenide. 721... Substances § 721.10391 Copper gallium indium selenide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as copper gallium indium selenide (PMN P-10...

  4. 40 CFR 721.10391 - Copper gallium indium selenide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Copper gallium indium selenide. 721... Substances § 721.10391 Copper gallium indium selenide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as copper gallium indium selenide (PMN P-10...

  5. Functionalized boron nitride nanotubes

    DOEpatents

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

    2014-04-22

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

  6. Aluminum nitride grating couplers.

    PubMed

    Ghosh, Siddhartha; Doerr, Christopher R; Piazza, Gianluca

    2012-06-10

    Grating couplers in sputtered aluminum nitride, a piezoelectric material with low loss in the C band, are demonstrated. Gratings and a waveguide micromachined on a silicon wafer with 600 nm minimum feature size were defined in a single lithography step without partial etching. Silicon dioxide (SiO(2)) was used for cladding layers. Peak coupling efficiency of -6.6 dB and a 1 dB bandwidth of 60 nm have been measured. This demonstration of wire waveguides and wideband grating couplers in a material that also has piezoelectric and elasto-optic properties will enable new functions for integrated photonics and optomechanics.

  7. Gallium nitride nanotube lasers

    DOE PAGES

    Li, Changyi; Liu, Sheng; Hurtado, Antonio; ...

    2015-01-01

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

  8. A modern perspective on the history of semiconductor nitride blue light sources

    NASA Astrophysics Data System (ADS)

    Maruska, Herbert Paul; Rhines, Walden Clark

    2015-09-01

    In this paper we shall discuss the development of blue light-emitting (LED) and laser diodes (LD), starting early in the 20th century. Various materials systems were investigated, but in the end, the nitrides of aluminum, gallium and indium proved to be the most effective. Single crystal thin films of GaN first emerged in 1968. Blue light-emitting diodes were first reported in 1971. Devices grown in the 1970s were prepared by the halide transport method, and were never efficient enough for commercial products due to contamination. Devices created by metal-organic vapor-phase epitaxy gave far superior performance. Actual true blue LEDs based on direct band-to-band transitions, free of recombination through deep levels, were finally developed in 1994, leading to a breakthrough in LED performance, as well as nitride based laser diodes in 1996. In 2014, the scientists who achieved these critical results were awarded the Nobel Prize in Physics.

  9. GaN-based light-emitting diodes with graphene/indium tin oxide transparent layer.

    PubMed

    Lai, Wei-Chih; Lin, Chih-Nan; Lai, Yi-Chun; Yu, Peichen; Chi, Gou Chung; Chang, Shoou-Jinn

    2014-03-10

    We have demonstrated a gallium nitride (GaN)-based green light-emitting diode (LED) with graphene/indium tin oxide (ITO) transparent contact. The ohmic characteristic of the p-GaN and graphene/ITO contact could be preformed by annealing at 500 °C for 5 min. The specific contact resistance of p-GaN/graphene/ITO (3.72E-3 Ω·cm²) is one order less than that of p-GaN/ITO. In addition, the 20-mA forward voltage of LEDs with graphene/ITO transparent (3.05 V) is 0.09 V lower than that of ITO LEDs (3.14 V). Besides, We have got an output power enhancement of 11% on LEDs with graphene/ITO transparent contact.

  10. Correct implementation of polarization constants in wurtzite materials and impact on III-nitrides

    DOE PAGES

    Dreyer, Cyrus E.; Janotti, Anderson; Van de Walle, Chris G.; ...

    2016-06-20

    Here, accurate values for polarization discontinuities between pyroelectric materials are critical for understanding and designing the electronic properties of heterostructures. For wurtzite materials, the zincblende structure has been used in the literature as a reference to determine the effective spontaneous polarization constants. We show that, because the zincblende structure has a nonzero formal polarization, this method results in a spurious contribution to the spontaneous polarization differences between materials. In addition, we address the correct choice of "improper" versus "proper" piezoelectric constants. For the technologically important III-nitride materials GaN, AlN, and InN, we determine polarization discontinuities using a consistent reference basedmore » on the layered hexagonal structure and the correct choice of piezoelectric constants, and discuss the results in light of available experimental data.« less

  11. Effects of hole localization on limiting p-type conductivity in oxide and nitride semiconductors

    SciTech Connect

    Lyons, J. L.; Janotti, A.; Van de Walle, C. G.

    2014-01-07

    We examine how hole localization limits the effectiveness of substitutional acceptors in oxide and nitride semiconductors and explain why p-type doping of these materials has proven so difficult. Using hybrid density functional calculations, we find that anion-site substitutional impurities in AlN, GaN, InN, and ZnO lead to atomic-like states that localize on the impurity atom itself. Substitution with cation-site impurities, on the other hand, triggers the formation of polarons that become trapped on nearest-neighbor anions, generally leading to large ionization energies for these acceptors. Unlike shallow effective-mass acceptors, these two types of deep acceptors couple strongly with the lattice, significantly affecting the optical properties and severely limiting prospects for achieving p-type conductivity in these wide-band-gap materials.

  12. Thermodynamic considerations of the vapor phase reactions in III-nitride metal organic vapor phase epitaxy

    NASA Astrophysics Data System (ADS)

    Sekiguchi, Kazuki; Shirakawa, Hiroki; Chokawa, Kenta; Araidai, Masaaki; Kangawa, Yoshihiro; Kakimoto, Koichi; Shiraishi, Kenji

    2017-04-01

    We analyzed the metal organic vapor phase epitaxial growth mechanism of the III-nitride semiconductors GaN, AlN, and InN by first-principles calculations and thermodynamic analyses. In these analyses, we investigated the decomposition processes of the group III source gases X(CH3)3 (X = Ga, Al, In) at finite temperatures and determined whether the (CH3)2GaNH2 adduct can be formed or not. The results of our calculations show that the (CH3)2GaNH2 adduct cannot be formed in the gas phase in GaN metal organic vapor phase epitaxy (MOVPE), whereas, in AlN MOVPE, the formation of the (CH3)2AlNH2 adduct in the gas phase is exclusive. In the case of GaN MOVPE, trimethylgallium (TMG, [Ga(CH3)3]) decomposition into Ga gas on the growth surface with the assistance of H2 carrier gas, instead of the formation of the (CH3)2GaNH2 adduct, occurs almost exclusively. Moreover, in the case of InN MOVPE, the formation of the (CH3)2InNH2 adduct does not occur and it is relatively easy to produce In gas even without H2 in the carrier gas.

  13. The rapid solid-state synthesis of group III and transition metal nitrides at ambient and high pressures

    NASA Astrophysics Data System (ADS)

    Wallace, Charles Henry

    The development and improvement of new and existing technologies requires the synthesis of ultra-pure, crystalline materials. To meet this need, new ways of synthesizing materials with specific properties that are difficult or impossible to produce using traditional methods must be developed. The research presented herein outlines various new techniques that can be effectively used to produce high quality, crystalline materials using a novel time and energy efficient process called solid-state metathesis. This process combines two or more solid, molecular precursors that react exothermically to rapidly produce crystalline refractory ceramic and electronic materials, such as binary and ternary metal carbides, nitrides, phosphides, sulfides and oxides. Several important materials, including graphite, gallium nitride, indium nitride, tantalum nitride, silicon nitride and cubic boron nitride, which had been difficult or impossible to synthesize using standard solid-state metathesis reactions, can now be synthesized using modified metathesis methods. One of the new techniques described in this thesis for the successful synthesis of materials, such as gallium nitride, is the use of high pressures (up to 80,000 atm) before initiating a solid-state reaction. New nitrogen precursors were investigated, such as lithium amide and ammonium chloride, which when combined in the proper ratios, aid in the formation of gallium and indium nitride at ambient pressures. The major focus of this work is on new synthetic techniques that rapidly produce pure, crystalline materials. Since gallium nitride is an important direct wide-bandgap semiconductor of interest for high brightness, blue light-emitting diodes, lasers and flat panel displays, a large majority of the research described has been devoted to developing more efficient methods for synthesizing and purifying high quality products. Also discussed is the importance of controlling the temperature by the addition of less reactive

  14. High Cubic-Phase Purity InN on MgO (001) Using Cubic-Phase GaN as a Buffer Layer

    SciTech Connect

    Sanorpim, S.; Kuntharin, S.; Parinyataramas, J.; Yaguchi, H.; Iwahashi, Y.; Orihara, M.; Hijikata, Y.; Yoshida, S.

    2011-12-23

    High cubic-phase purity InN films were grown on MgO (001) substrates by molecular beam epitaxy with a cubic-phase GaN buffer layer. The cubic phase purity of the InN grown layers has been analyzed by high resolution X-ray diffraction, {mu}-Raman scattering and transmission electron microscopy. It is evidenced that the hexagonal-phase content in the InN overlayer much depends on hexagonal-phase content in the cubic-phase GaN buffer layer and increases with increasing the hexagonal-phase GaN content. From Raman scattering measurements, in addition, the InN layer with lowest hexagonal component (6%), only Raman characteristics of cubic TO{sub InN} and LO{sub InN} modes were observed, indicating a formation of a small amount of stacking faults, which does not affect on vibrational property.

  15. Group III-nitride based hetero and quantum structures

    NASA Astrophysics Data System (ADS)

    Monemar, B.; Pozina, G.

    2000-11-01

    The present paper attempts an overview of a presently very active research field: the III-nitrides and their interesting possibilities for a range of device applications employing heterostructures and low-dimensional quantum structures. The family of materials containing AlN, GaN, InN and the alloys between them span a range of direct bandgaps between 6.2 and 1.9 eV, with very large band offsets in type I heterojunctions, which is very favourable for a number of interesting device concepts. A very important feature of these materials is the dominant influence of strong polarisation fields (spontaneous as well as piezo-electric) on the physical properties of multilayer structures, as well as on devices. Exciton binding energies are large, and excitonic effects are therefore important at room temperature. Many alloy systems, in particular InGaN, have a high miscibility gap, leading to a strong tendency for phase separation and consequently to many novel physical properties which yet have to be explored in detail. Localization effects for carriers and excitons are very important in quantum structures based on these alloys. Devices based on III-N heterostructures cover a wide range, from optical devices (violet lasers, LEDs covering a range from UV to red, white LEDs, photodetectors, UV cameras) to high-frequency power devices, both unipolar transistors (AlGaN/GaN HEMTs) and bipolar HBTs.

  16. Hard carbon nitride and method for preparing same

    DOEpatents

    Haller, Eugene E.; Cohen, Marvin L.; Hansen, William L.

    1992-01-01

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

  17. [Investigation of indium exposure in workers in indium smelting plant].

    PubMed

    Ding, C G; Yan, H F; Wang, H Q; Li, T

    2016-04-20

    To investigate the internal and external exposure levels of indium (In)in workers in an In smelting plant, and to analyze its distribution characteristics. A survey was performed in 63 employed workers with more than one year of experience working in an In smelting plant in 2014. The personal air samples for 31 workers were collected, and the whole blood, serum, and urine samples of all the 63 workers were collected to do the occupational health examination at the same time. In levels in all samples were determined by inductively coupled plasma mass spectrometry. The smelter workers had a higher In exposure level in the air than the office workers (2.26 μg/m(3) vs 0.82 μg/m(3), P>0.05). There was a significant difference in In exposure level in the air between the workers doing different types of jobs (P<0.05). The In exposure levels in the air in the metathesis workers and electrolysis workers were 26.10 μg/m(3) and 20.99 μg/m(3), respectively, which were significantly higher than those in other workers (P<0.05). The smelter workers had significantly higher geometric means of In levels in the whole blood, serum, and urine than the office workers (0.44 μg/L vs 0.09 μg/L, P<0.05; 0.35 μg/L vs 0.09 μg/L, P<0.05; 0.26 μg/L vs 0.12 μg/L, P<0.05). There were significant differences in In levels in the whole blood, serum, and urine between the workers doing different types of jobs (P<0.05). The metathesis workers (13.0 μg/L, 4.02 μg/L, and 2.93 μg/L)and electrolysis workers (5.71 μg/L, 5.14 μg/L, and 4.26 μg/L)had higher In levels in the whole blood, serum, and urine than other workers. The In level in the whole blood was positively correlated with the In levels in the urine and serum (rs=0.601, P<0.05; rs=0.823, P<0.05). The In levels in the whole blood and urine were positively correlated with the In level in the air(rs=0.483, P<0.05; rs=0.428, P<0.05). In the In smelting plant, the In concentrations in the air are lower than the standard value, but the

  18. A biokinetic and dosimetric model for ionic indium in humans

    NASA Astrophysics Data System (ADS)

    Andersson, Martin; Mattsson, Sören; Johansson, Lennart; Leide-Svegborn, Sigrid

    2017-08-01

    This paper reviews biokinetic data for ionic indium, and proposes a biokinetic model for systemic indium in adult humans. The development of parameter values focuses on human data and indium in the form of ionic indium(III), as indium chloride and indium arsenide. The model presented for systemic indium is defined by five different pools: plasma, bone marrow, liver, kidneys and other soft tissues. The model is based on two subsystems: one corresponding to indium bound to transferrin and one where indium is transported back to the plasma, binds to red blood cell transferrin and is then excreted through the kidneys to the urinary bladder. Absorbed doses to several organs and the effective dose are calculated for 111In- and 113mIn-ions. The proposed biokinetic model is compared with previously published biokinetic indium models published by the ICRP. The absorbed doses are calculated using the ICRP/ICRU adult reference phantoms and the effective dose is estimated according to ICRP Publication 103. The effective doses for 111In and 113mIn are 0.25 mSv MBq-1 and 0.013 mSv MBq-1 respectively. The updated biokinetic and dosimetric models presented in this paper take into account human data and new animal data, which represent more detailed and presumably more accurate dosimetric data than that underlying previous models for indium.

  19. Developmental toxicity of indium: embryotoxicity and teratogenicity in experimental animals.

    PubMed

    Nakajima, Mikio; Usami, Makoto; Nakazawa, Ken; Arishima, Kazuyoshi; Yamamoto, Masako

    2008-12-01

    Indium, a precious metal classified in group 13 (IIIB) in the periodic table, has been used increasingly in the semiconductor industry. Because indium is a rare metal, technology for indium recycling from transparent conducting films for liquid crystal displays is desired, and its safety evaluation is becoming increasingly necessary. The developmental toxicity of indium in experimental animals was summarized. The intravenous or oral administration of indium to pregnant animals causes growth inhibition and the death of embryos in hamsters, rats, and mice. The intravenous administration of indium to pregnant animals causes embryonic or fetal malformation, mainly involving digit and tail deformities, in hamsters and rats. The oral administration of indium also induces fetal malformation in rats and rabbits, but requires higher doses. No teratogenicity has been observed in mice. Caudal hypoplasia, probably due to excessive cell loss by increased apoptosis in the tailbud, in the early postimplantation stage was considered to account for indium-induced tail malformation as a possible pathogenetic mechanism. Findings from in vitro experiments indicated that the embryotoxicity of indium could have direct effects on the conceptuses. Toxicokinetic studies showed that the embryonic exposure concentration was more critical than the exposure time regarding the embryotoxicity of indium. It is considered from these findings that the risk of the developmental toxicity of indium in humans is low, unless an accidentally high level of exposure or unknown toxic interaction occurs because of possible human exposure routes and levels (i.e. oral, very low-level exposure).

  20. Proteomic analysis of indium embryotoxicity in cultured postimplantation rat embryos.

    PubMed

    Usami, Makoto; Nakajima, Mikio; Mitsunaga, Katsuyoshi; Miyajima, Atsuko; Sunouchi, Momoko; Doi, Osamu

    2009-12-01

    Indium embryotoxicity was investigated by proteomic analysis with two-dimensional electrophoresis of rat embryos cultured from day 10.5 of gestation for 24h in the presence of 50 microM indium trichloride. In the embryo proper, indium increased quantity of several protein spots including those identified as serum albumin, phosphorylated cofilin 1, phosphorylated destrin and tyrosyl-tRNA synthetase. The increased serum albumin, derived from the culture medium composed of rat serum, may decrease the toxicity of indium. The increase of phosphorylated cofilin 1 might be involved in dysmorphogenicity of indium through perturbation of actin functions. In the yolk sac membrane, indium induced quantitative and qualitative changes in the protein spots. Proteins from appeared spots included stress proteins, and those from decreased or disappeared spots included serum proteins, glycolytic pathway enzymes and cytoskeletal proteins, indicating yolk sac dysfunction. Thus, several candidate proteins that might be involved in indium embryotoxicity were identified.

  1. Relationship between indium exposure and oxidative damage in workers in indium tin oxide production plants.

    PubMed

    Liu, Hung-Hsin; Chen, Chang-Yun; Chen, Gun-Ing; Lee, Lien-Hsiung; Chen, Hsiu-Ling

    2012-05-01

    The study aimed to assess the relationship between indium exposure and surfactant protein and any oxidative damage in indium tin oxide (ITO)-exposed workers. The study was conducted in two typical ITO-manufacturing plants in Taiwan. One hundred and seventy manufacturing workers and 132 administrators were recruited. The geometric mean serum indium (S-In) level in the workers of the manufacturing department was 1.26 μg/l, which was significantly higher than those in the administrative department (0.72 μg/l). The S-In levels of 49 workers were higher than 3 μg/l (49/302, 16.2%), exceeding an occupational exposure limit suggested by the Japan Society for Occupational Health. Significant positive relationships were found between S-In and surfactant protein A (SP-A), and surfactant protein D (SP-D) levels. SP-A and SP-D levels were elevated significantly in the workers with moderately high indium exposure. The present study indicates a significant elevating trend of SP-A and SP-D levels in ITO-manufacturing workers, which are sensitive markers of interstitial lung disease. Though the indium exposure is not directly linked to all indicators of oxidative DNA damage, the ITO-manufacturing workplace is suggested to be related to oxidative DNA damage for the workers in the current study. Therefore, in addition to the indium exposure, there might be other occupational hazards in the ITO workplace to cause oxidative damage.

  2. Sinterless Formation Of Contacts On Indium Phosphide

    NASA Technical Reports Server (NTRS)

    Weizer, Victor G.; Fatemi, Navid S.

    1995-01-01

    Improved technique makes it possible to form low-resistivity {nearly equal to 10(Sup-6) ohm cm(Sup2)} electrical contacts on indium phosphide semiconductor devices without damaging devices. Layer of AgP2 40 Angstrom thick deposited on InP before depositing metal contact. AgP2 interlayer sharply reduces contact resistance, without need for sintering.

  3. Sinterless Formation Of Contacts On Indium Phosphide

    NASA Technical Reports Server (NTRS)

    Weizer, Victor G.; Fatemi, Navid S.

    1995-01-01

    Improved technique makes it possible to form low-resistivity {nearly equal to 10(Sup-6) ohm cm(Sup2)} electrical contacts on indium phosphide semiconductor devices without damaging devices. Layer of AgP2 40 Angstrom thick deposited on InP before depositing metal contact. AgP2 interlayer sharply reduces contact resistance, without need for sintering.

  4. Synthesis of ternary metal nitride nanoparticles using mesoporous carbon nitride as reactive template.

    PubMed

    Fischer, Anna; Müller, Jens Oliver; Antonietti, Markus; Thomas, Arne

    2008-12-23

    Mesoporous graphitic carbon nitride was used as both a nanoreactor and a reactant for the synthesis of ternary metal nitride nanoparticles. By infiltration of a mixture of two metal precursors into mesoporous carbon nitride, the pores act first as a nanoconfinement, generating amorphous mixed oxide nanoparticles. During heating and decomposition, the carbon nitride second acts as reactant or, more precisely, as a nitrogen source, which converts the preformed mixed oxide nanoparticles into the corresponding nitride (reactive templating). Using this approach, ternary metal nitride particles with diameters smaller 10 nm composed of aluminum gallium nitride (Al-Ga-N) and titanium vanadium nitride (Ti-V-N) were synthesized. Due to the confinement effect of the carbon nitride matrix, the composition of the resulting metal nitride can be easily adjusted by changing the concentration of the preceding precursor solution. Thus, ternary metal nitride nanoparticles with continuously adjustable metal composition can be produced.

  5. Physical vapor transport growth of aluminum nitride

    NASA Astrophysics Data System (ADS)

    Letts, Edward Robert

    Conventional III:nitride devices are grown on sapphire or SiC. This heterogeneous growth induces significant performance limiting aspects, such as stress and high dislocation densities for the resultant devices. Physical Vapor Transport (PVT) growth of AlN was investigated to produce free standing crystals suitable for homogenous substrate use. AlN bulk single crystals were grown by spontaneous nucleation on the side wall of a Hot Pressed BN (HPBN) crucible, using both commercial Al metal and AlN powder as source materials in an open system to produce a-plane crystal platelet. The crystals had low (11-20) o rocking curves with full-width at half-maximum values of 17-60 arcsecs, indicative of their high crystalline quality. Furthermore, the addition of 1% indium by weight to the source material was found to significantly influence growth and nucleation site formation. Despite their high quality, the crystals could not be scaled for substrate use because of the limited size and morphology of the crystals. Hot Pressed TaC (HP-TaC) crucibles were fabricated in house by sintering TaC powder in a hot press furnace. The resulting crucibles were stable for several hundred hours at growth temperatures in excess of 2300°C. The resulting AlN growth in the HP-TaC crucibles produced a polycrystalline boule. Grain growth was obtained in a single growth, however further optimization was required to control spontaneous nucleation site formation during the initial stage of a regrowth. Continuous grain growth was achieved by controlling oxygen contaminants which allowed the production of a single grain with a horizontal cross-section 23 mm2 in size. Methods to support seed crystals were developed and seeded growth was attempted to allow the growth of substrates suitable for device growth.

  6. Method for producing refractory nitrides

    DOEpatents

    Quinby, Thomas C.

    1989-01-24

    A process for making fine, uniform metal nitride powders that can be hot pressed or sintered. A metal salt is placed in a solvent with Melamine and warmed until a metal-Melamine compound forms. The solution is cooled and the metal-Melamine precipitate is calcined at a temperature below 700.degree. C. to form the metal nitrides and to avoid formation of the metal oxide.

  7. Boron nitride converted carbon fiber

    SciTech Connect

    Rousseas, Michael; Mickelson, William; Zettl, Alexander K.

    2016-04-05

    This disclosure provides systems, methods, and apparatus related to boron nitride converted carbon fiber. In one aspect, a method may include the operations of providing boron oxide and carbon fiber, heating the boron oxide to melt the boron oxide and heating the carbon fiber, mixing a nitrogen-containing gas with boron oxide vapor from molten boron oxide, and converting at least a portion of the carbon fiber to boron nitride.

  8. Aluminum Nitride Grown by Atomic Layer Epitaxy Characterized with Real-Time Grazing Incidence Small Angle X-ray Scattering

    NASA Astrophysics Data System (ADS)

    Anderson, Virginia; Nepal, Neeraj; Johnson, Scooter; Robinson, Zachary; Demasi, Alexander; Hite, Jennifer; Ludwig, Karl; Eddy, Charles

    Aluminum nitride, gallium nitride, and indium nitride are being considered for many applications, and are currently being used commercially for LEDs. These III-nitride films are conventionally deposited by metalorganic chemical vapor deposition and molecular beam epitaxy. Research into depositing III-nitrides with atomic layer epitaxy (ALE) is underway as it is a fabrication friendly technique for thin films at lower temperatures. AlN deposited with ALE at 500°C have been shown to have good crystallinity, but relatively high carbon and oxygen impurities, and understanding the film deposition mechanism is an ongoing project. Grazing incidence small angle x-ray scattering (GISAXS) is sensitive to surface features, making it useful for real time monitoring of deposition processes. AlN was monitored by GISAXS while being deposited with ALE using trimethylaluminum and hydrogen/nitrogen plasma at the Brookhaven National Synchrotron Light Source and the Cornell High Energy Synchrotron Source. The GISAXS of AlN ALE at nominally 400°C, 450°C, and 500°C was compared to ex situ characterization with XPS and AFM.

  9. Hemocompatibility of titanium nitride.

    PubMed

    Dion, I; Baquey, C; Candelon, B; Monties, J R

    1992-10-01

    The left ventricular assist device is based on the principle of the Maillard-Wenkel rotative pump. The materials which make up the pump must present particular mechanical, tribological, thermal and chemical properties. Titanium nitride (TiN) because of its surface properties and graphite because of its bulk characteristics have been chosen. The present study evaluated the in vitro hemocompatibility of TiN coating deposited by the chemical vapor deposition process. Protein adsorption, platelet retention and hemolysis tests have been carried out. In spite of some disparities, the TiN behavior towards albumin and fibrinogen is interesting, compared with the one of a reference medical grade elastomer. The platelet retention test gives similar results as those achieved with the same elastomer. The hemolysis percentage is near to zero. TiN shows interesting characteristics, as far as mechanical and tribological problems are concerned, and presents very encouraging blood tolerability properties.

  10. Silicon nitride membrane photonics

    NASA Astrophysics Data System (ADS)

    Pernice, W. H. P.; Li, M.; Gallagher, D. F. G.; Tang, H. X.

    2009-11-01

    We propose a concept for realizing large area nanophotonic circuits in a silicon nitride membrane. Light is coupled into the membrane using a novel metallic photonic crystal grating coupler. A coupling loss of 5.5 dB is predicted for TE polarized light at 1550 nm. Waveguiding at telecoms wavelengths is achieved by using low loss photonic crystal defect waveguides. The propagation losses of the photonic crystal waveguides are estimated at 8.6 dB mm-1, comparable to early silicon photonic crystal waveguides. Using the proposed approach, photonic circuits can be fabricated using a single lithography and etching step. Thus the design scheme shows a route to low-cost fabrication.

  11. Nano boron nitride flatland.

    PubMed

    Pakdel, Amir; Bando, Yoshio; Golberg, Dmitri

    2014-02-07

    Recent years have witnessed many breakthroughs in research on two-dimensional (2D) nanomaterials, among which is hexagonal boron nitride (h-BN), a layered material with a regular network of BN hexagons. This review provides an insight into the marvellous nano BN flatland, beginning with a concise introduction to BN and its low-dimensional nanostructures, followed by an overview of the past and current state of research on 2D BN nanostructures. A comprehensive review of the structural characteristics and synthetic routes of BN monolayers, multilayers, nanomeshes, nanowaves, nanoflakes, nanosheets and nanoribbons is presented. In addition, electronic, optical, thermal, mechanical, magnetic, piezoelectric, catalytic, ecological, biological and wetting properties, applications and research perspectives for these novel 2D nanomaterials are discussed.

  12. Magnetic iron nitride nanodendrites

    SciTech Connect

    Cao Minhua . E-mail: caomh043@nenu.edu.cn; Liu Tianfu; Sun Genban; Wu Xinglong; He, Xiaoyan; Hu Changwen

    2005-07-15

    We report the synthesis of Fe{sub 3}N nanodendrites directly by reduction-nitriding of {alpha}-Fe{sub 2}O{sub 3} nanopine dendrites in a mixed stream of H{sub 2}-NH{sub 3}. Fe{sub 3}N basically retains dendritic morphology of the starting material {alpha}-Fe{sub 2}O{sub 3.} It is found that nanorod branches of Fe{sub 3}N dendrites have relatively uniform diameters and are evenly distributed at both sides of the stem with a periodicity of about 50nm. The diameters of the nanorods are about 50nm, and their lengths range from 50 to 1000nm. Fe{sub 3}N nanodendrites show a rapid saturation of magnetization of 104emu/g at 300K, as expected for a magnet.

  13. Superplastic forging nitride ceramics

    DOEpatents

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

    1988-03-22

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

  14. InN nanorods prepared with CrN nanoislands by plasma-assisted molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Liu, Kuang-Wei; Chang, Shoou-Jinn; Young, Sheng-Joue; Hsueh, Tao-Hung; Hung, Hung; Mai, Yu-Chun; Wang, Shih-Ming; Chen, Kuan-Jen; Wu, Ya-Ling; Chen, Yue-Zhang

    2011-07-01

    The authors report the influence of CrN nanoisland inserted on growth of baseball-bat InN nanorods by plasma-assisted molecular beam epitaxy under In-rich conditions. By inserting CrN nanoislands between AlN nucleation layer and the Si (111) substrate, it was found that we could reduce strain form Si by inserting CrN nanoisland, FWHM of the x-ray rocking curve measured from InN nanorods from 3,299 reduced to 2,115 arcsec. It is due to the larger strain from lattice miss-match of the film-like InN structure; however, the strain from lattice miss-match was obvious reduced owing to CrN nanoisland inserted. The TEM images confirmed the CrN structures and In droplets dissociation from InN, by these results, we can speculate the growth mechanism of baseball-bat-like InN nanorods.

  15. Fundamental optical properties of InN grown by epitaxial lateral overgrowth method

    SciTech Connect

    Kametani, Tatsuma; Kamimura, Jumpei; Inose, Yuta; Kunugita, Hideyuki; Kikuchi, Akihiko; Kishino, Katsumi; Ema, Kazuhiro

    2013-12-04

    Optical properties of InN grown by the epitaxial lateral overgrowth (ELO) method have been studied using photoluminescence (PL) and excitation-correlation (EC) measurements. The PL spectrum is analyzed by free-electron recombination band (FERB) model, which shows that the ELO sample has a very low background carrier concentration (n=5.5*10{sup 16}[cm{sup −3]}). EC measurements show that the dependences of the band gap renormalization and Auger effect on the carrier concentrations are similar in spite of the different physical origins.

  16. Infrared analysis of hole properties of Mg-doped p-type InN films

    SciTech Connect

    Fujiwara, Masayuki; Ishitani, Yoshihiro; Wang Xinqiang; Che, Song-Bek; Yoshikawa, Akihiko

    2008-12-08

    Mg-doped InN films grown by plasma-assisted molecular beam epitaxy were characterized by infrared reflectance. Signatures of p-type conductivity in the spectra were obtained in the same doping density range where the existence of net acceptors was found by electrolyte capacitance-voltage measurements. Numerical spectrum analysis, which takes into account the large broadening factor of the normal mode energies of longitudinal optical phonon-plasmon coupling yielded high hole densities in the range of (0.1-1.2)x10{sup 19} cm{sup -3} and optical mobilities in the range of 25-70 cm{sup 2}/V s.

  17. Structural Differences in Mg-doped InN - Indication of Polytypism

    DTIC Science & Technology

    2010-01-01

    accumulation layer over- come by using electrolyte-based capacitance-voltage ( ECV ) measurements [6,7] and a combination of Hall ef- fect, photoluminescence...and ECV analysis [8]. Mg doped InN thin films were confirmed to be p-type. However, there are only few reports on structural properties of this...an increase of Mg concentration above 1.8x1020 cm-3 using ECV measure- ments leads to a change from p-conductivity to n-type. This concentration

  18. Nqrs Data for C10H12Br5Cl2InN2O [C10H10Br5Cl2InN2·H2O] (Subst. No. 1254)

    NASA Astrophysics Data System (ADS)

    Chihara, H.; Nakamura, N.

    This document is part of Subvolume A `Substances Containing Ag … C10H15' of Volume 48 `Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III `Condensed Matter'. It contains an extract of Section `3.2 Data tables' of the Chapter `3 Nuclear quadrupole resonance data' providing the NQRS data for C10H12Br5Cl2InN2O [C10H10Br5Cl2InN2·H2O] (Subst. No. 1254)

  19. Near-infrared InN quantum dots on high-In composition InGaN

    SciTech Connect

    Soto Rodriguez, Paul E. D.; Gomez, Victor J.; Kumar, Praveen; Calleja, Enrique; Noetzel, Richard

    2013-04-01

    We report the growth of InN quantum dots (QDs) on thick InGaN layers with high In composition (>50%) by molecular beam epitaxy. Optimized growth conditions are identified for the InGaN layers at reduced growth temperature and increased active N flux resulting in minimized phase separation and defect generation. The InN QDs grown on top of the optimized InGaN layer exhibit small size, high density, and photoluminescence up to room temperature. The InN/InGaN QDs reveal excellent potential for intermediate band solar cells with the InGaN and InN QD bandgap energies tuned to the best match of absorption to the solar spectrum.

  20. A comparative investigation on sub-micrometer InN and GaN Gunn diodes working at terahertz frequency

    NASA Astrophysics Data System (ADS)

    Yang, Lin'an; Long, Shuang; Guo, Xin; Hao, Yue

    2012-05-01

    We report on a simulation for wurtzite-InN and GaN Gunn diodes with notch-doping and uniform-doping structural transit regions. Results show that 0.3-1.0 μm Gunn diodes with a diode area of 500 μm2 can generate fundamental frequencies of around 0.2-0.8 THz and rf currents of several hundred mA. InN diodes exhibit more stable oscillations, whereas GaN diodes generate higher oscillation frequencies at both dipole-domain mode and accumulation-domain mode due to different negative differential resistance (NDR) characteristics of high-field transport. The sharp NDR region of InN makes it more suitable for short transit region Gunn diode. Higher Irf/Iav and lower bias voltage in InN Gunn diode imply its conversion efficiency significantly higher than GaN diode.

  1. Valence band offset of MgO /InN heterojunction measured by x-ray photoelectron spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhang, P. F.; Liu, X. L.; Zhang, R. Q.; Fan, H. B.; Song, H. P.; Wei, H. Y.; Jiao, C. M.; Yang, S. Y.; Zhu, Q. S.; Wang, Z. G.

    2008-01-01

    MgO may be a promising gate dielectric and surface passivation film for InN based devices and the valence band offset of MgO /InN heterojunction has been measured by x-ray photoelectron spectroscopy. The valence band offset is determined to be 1.59±0.23eV. Given the experimental band gap of 7.83 for the MgO, a type-I heterojunction with a conduction band offset of 5.54±0.23eV is found. The accurate determination of the valence and conduction band offsets is important for use of MgO /InN electronic devices.

  2. Nitride precipitation in salt-bath nitrided interstitial-free steel

    SciTech Connect

    Lee, Tae-Ho; Oh, Chang-Seok; Lee, Min-Ku; Han, Sang-Won

    2010-10-15

    Nitride precipitation and its effect on microstrain in salt-bath nitrided interstitial-free steel were investigated using transmission electron microscopy and neutron diffraction. As the cooling rate after nitriding decreased, two nitrides, {gamma}'-Fe{sub 4}N and {alpha}{sup -}Fe{sub 16}N{sub 2}, were identified in diffusion zone. Combined analyses using Rietveld whole-profile fitting and size-strain analysis revealed that the microstrain in the nitrided specimen increased due to nitrogen supersaturation and then decreased after nitride precipitation, whereas the effective particle size continuously decreased. It was found that microstrain is the dominant factor in peak broadening of the nitrided specimen.

  3. First-principles investigations of III-nitride bulk and surface properties

    NASA Astrophysics Data System (ADS)

    Dreyer, Cyrus Eduard

    The III-nitride semiconductors, including AlN, InN, GaN, and BN have been demonstrated as technologically exciting materials for a wide range of device applications. With band gaps that span the visible range, GaN, InN, and InGaN alloys are used for high efficiency light emitting diodes for general lighting, as well as laser diodes for optical storage. The wide gaps, large band offsets, and polarization fields in AlN, GaN, and AlGaN alloys are promising for high-frequency, high-power transistors with applications in power conversion and radio frequency amplifiers. Despite the plethora of attractive material parameters of the III-nitride materials there are several issues that significantly limit the efficiency of devices and range of possible applications. In this study, we use first-principles electronic structure calculations to explore several of these properties relevant to understanding growth, processing, and device design. Arguably the most detrimental issue in this material system is the lack of widely available, cost-effective substrates for the growth of films and devices. Heteroepitaxy, as well as the lattice mismatch between the layers of different III-nitride alloys in heterostructures, results in residual stresses in films and devices. Such stress will alter the electronic structure of the materials, so it is necessary for device design to be able to quantify these effects. We explore the influence of strain on the effective mass of carriers in GaN and AlN, a parameter that is tied to the conductivity. In addition, films under tensile strain can crack if the strain energy is sufficient. We explore the propensity for AlN, GaN, and AlGaN to crack on different crystallographic planes. There has been significant work done to overcome the issue of residual strains in III-nitride films, both through the growth of bulk crystals for substrates, and the growth of structures such as nanowires that avoid many of the thickness and alloy-content limitations of

  4. Two- and 13-week inhalation toxicities of indium-tin oxide and indium oxide in rats.

    PubMed

    Nagano, Kasuke; Gotoh, Kaoru; Kasai, Tatsuya; Aiso, Shigetoshi; Nishizawa, Tomoshi; Ohnishi, Makoto; Ikawa, Naoki; Eitaki, Yoko; Yamada, Kenichi; Arito, Heihachiro; Fukushima, Shoji

    2011-01-01

    Two- and 13-week inhalation toxicities of indium-tin oxide (ITO) and indium oxide (IO) were characterized for risk assessments of workers exposed to ITO. F344 rats of both sexes were exposed by inhalation to ITO or IO aerosol for 6 h/day, 5 day/wk for 2 wk at 0, 0.1, 1, 10 or 100 mg/m(3) or 13 wk at 0, 0.1 or 1 mg/m(3). An aerosol generator and inhalation exposure system was constructed. Blood and lung contents of indium were elevated in a dose-related manner in the ITO- and IO-exposed rats. ITO and IO particles were deposited in the lung, mediastinal lymph node and nasal-associated lymphoid tissue. Exposures to ITO and IO induced alveolar proteinosis, infiltrations of alveolar macrophages and inflammatory cells and alveolar epithelial hyperplasia in addition to increased lung weight. ITO affected the lung more severely than IO did. Fibrosis of alveolar wall developed and some of these lesions worsened at the end of the 26-week post-exposure period. Persistent pulmonary lesions including alveolar proteinosis and macrophage infiltration occurred after 2- and 13-week inhalation exposures of rats to ITO and IO. Fibrosis of alveolar wall developed later. These lesions occurred after ITO exposure at the same concentration as the current occupational exposure limit in the USA and at blood indium levels below the biological exposure index in Japan for indium.

  5. Indium and indium tin oxide induce endoplasmic reticulum stress and oxidative stress in zebrafish (Danio rerio).

    PubMed

    Brun, Nadja Rebecca; Christen, Verena; Furrer, Gerhard; Fent, Karl

    2014-10-07

    Indium and indium tin oxide (ITO) are extensively used in electronic technologies. They may be introduced into the environment during production, use, and leaching from electronic devices at the end of their life. At present, surprisingly little is known about potential ecotoxicological implications of indium contamination. Here, molecular effects of indium nitrate (In(NO3)3) and ITO nanoparticles were investigated in vitro in zebrafish liver cells (ZFL) cells and in zebrafish embryos and novel insights into their molecular effects are provided. In(NO3)3 led to induction of endoplasmic reticulum (ER) stress response, induction of reactive oxygen species (ROS) and induction of transcripts of pro-apoptotic genes and TNF-α in vitro at a concentration of 247 μg/L. In(NO3)3 induced the ER stress key gene BiP at mRNA and protein level, as well as atf6, which ultimately led to induction of the important pro-apoptotic marker gene chop. The activity of In(NO3)3 on ER stress induction was much stronger than that of ITO, which is explained by differences in soluble free indium ion concentrations. The effect was also stronger in ZFL cells than in zebrafish embryos. Our study provides first evidence of ER stress and oxidative stress induction by In(NO3)3 and ITO indicating a critical toxicological profile that needs further investigation.

  6. Performance of GaN-on-Si-based vertical light-emitting diodes using silicon nitride electrodes with conducting filaments: correlation between filament density and device reliability.

    PubMed

    Kim, Kyeong Heon; Kim, Su Jin; Lee, Tae Ho; Lee, Byeong Ryong; Kim, Tae Geun

    2016-08-08

    Transparent conductive electrodes with good conductivity and optical transmittance are an essential element for highly efficient light-emitting diodes. However, conventional indium tin oxide and its alternative transparent conductive electrodes have some trouble with a trade-off between electrical conductivity and optical transmittance, thus limiting their practical applications. Here, we present silicon nitride transparent conductive electrodes with conducting filaments embedded using the electrical breakdown process and investigate the dependence of the conducting filament density formed in the transparent conductive electrode on the device performance of gallium nitride-based vertical light-emitting diodes. Three gallium nitride-on-silicon-based vertical light-emitting diodes using silicon nitride transparent conductive electrodes with high, medium, and low conducting filament densities were prepared with a reference vertical light-emitting diode using metal electrodes. This was carried to determine the optimal density of the conducting filaments in the proposed silicon nitride transparent conductive electrodes. In comparison, the vertical light-emitting diodes with a medium conducting filament density exhibited the lowest optical loss, direct ohmic behavior, and the best current injection and distribution over the entire n-type gallium nitride surface, leading to highly reliable light-emitting diode performance.

  7. Ion-beam nitriding of steels

    NASA Technical Reports Server (NTRS)

    Salik, J.

    1984-01-01

    The application of the ion beam technique to the nitriding of steels is described. It is indicated that the technique can be successfully applied to nitriding. Some of the structural changes obtained by this technique are similar to those obtained by ion nitriding. The main difference is the absence of the iron nitride diffraction lines. It is found that the dependence of the resultant microhardness on beam voltage for super nitralloy is different from that of 304 stainless steel.

  8. Ion-beam nitriding of steels

    NASA Technical Reports Server (NTRS)

    Salik, J.

    1985-01-01

    The application of the ion beam technique to the nitriding of steels is described. It is indicated that the technique can be successfully applied to nitriding. Some of the structural changes obtained by this technique are similar to those obtained by ion nitriding. The main difference is the absence of the iron nitride diffraction lines. It is found that the dependence of the resultant microhardness on beam voltage for super nitralloy is different from that of 304 stainless steel.

  9. From Amateur Astronomer to Observatory Director: The Curious Case of R. T. A. Innes

    NASA Astrophysics Data System (ADS)

    Orchiston, Wayne

    Robert Innes was one of a select band of amateur astronomers who made the transition to professional ranks towards the end of the nineteenth century. Initially he had a passion for mathematical astronomy, but after settling in Sydney he developed a taste for observational astronomy, specialising in the search for new double stars. He quickly became known for his success in this field and for his publications on solar system perturbations, and with John Tebbutt's patronage managed to secure a clerical position at the Royal Observatory, Cape of Good Hope. Once there he continued to observe in his spare time and to publish, and, with strong support from Sir David Gill, was appointed founding Director of the Transvaal Observatory. By the time he died in 1933, Innes had received an honorary D.Sc. from Leiden University, and had established an international reputation as a positional astronomer. This paper provides an interesting case study of a well-known `amateur-turned-professional', and an example of the ways in which patronage played a key role in nineteenth and early twentieth century Australian and South African astronomy.

  10. Planar n +-in-n silicon pixel sensors for the ATLAS IBL upgrade

    NASA Astrophysics Data System (ADS)

    Goessling, C.; Klingenberg, R.; Muenstermann, D.; Rummler, A.; Troska, G.; Wittig, T.

    2011-09-01

    The ATLAS experiment at the LHC is planning to upgrade its pixel detector by the installation of a 4th pixel layer, the insertable b-layer IBL with a mean sensor radius of only 32 mm from the beam axis. Being very close to the beam, the radiation damage of the IBL sensors might be as high as 5×10 15 n eq cm -2 at their end-of-life. To investigate the radiation hardness and suitability of the current ATLAS pixel sensors for IBL fluences, n +-in-n silicon pixel sensors from the ATLAS Pixel production have been irradiated by reactor neutrons to the IBL design fluence and been tested with pions at the SPS and with electrons from a 90Sr source in the laboratory. The collected charge was found to exceed 10 000 electrons per MIP at 1 kV of bias voltage which is in agreement with data collected with strip sensors. With an expected threshold of 3000-4000 electrons, this result suggests that planar n +-in-n pixel sensors are radiation hard enough to be used as IBL sensor technology.

  11. Sorption of indium (III) onto carbon nanotubes.

    PubMed

    Alguacil, F J; Lopez, F A; Rodriguez, O; Martinez-Ramirez, S; Garcia-Diaz, I

    2016-08-01

    Indium has numerous applications in different industrial sectors and is not an abundant element. Therefore appropriate technology to recover this element from various process wastes is needed. This research reports high adsorption capacity of multiwalled carbon nanotubes (MWCNT) for In(III). The effects of pH, kinetics, isotherms and adsorption mechanism of MWCNT on In(III) adsorption were investigated and discussed in detail. The pH increases improves the adsorption capacity for In(III). The Langmuir adsorption model is the best fit with the experimental data. For the kinetic study, the adsorption onto MWCNT could be fitted to pseudo second-order. The adsorption of indium(III) can be described to a mechanism which consists of a film diffusion controlled process. Metal desorption can be achieved with acidic solutions. Copyright © 2016. Published by Elsevier Inc.

  12. Electronic properties of III-nitride semiconductors: A first-principles investigation using the Tran-Blaha modified Becke-Johnson potential

    SciTech Connect

    Araujo, Rafael B. Almeida, J. S. de Ferreira da Silva, A.

    2013-11-14

    In this work, we use density functional theory to investigate the influence of semilocal exchange and correlation effects on the electronic properties of III-nitride semiconductors considering zinc-blende and wurtzite crystal structures. We find that the inclusion of such effects through the use of the Tran-Blaha modified Becke-Johnson potential yields an excellent description of the electronic structures of these materials giving energy band gaps which are systematically larger than the ones obtained with standard functionals such as the generalized gradient approximation. The discrepancy between the experimental and theoretical band gaps is then significantly reduced with semilocal exchange and correlation effects. However, the effective masses are overestimated in the zinc-blende nitrides, but no systematic trend is found in the wurtzite compounds. New results for energy band gaps and effective masses of zinc-blende and wurtzite indium nitrides are presented.

  13. Growth of wurtzite InN on bulk In{sub 2}O{sub 3}(111) wafers

    SciTech Connect

    Sadofev, Sergey; Cho, Yong Jin; Brandt, Oliver; Ramsteiner, Manfred; Calarco, Raffaella; Riechert, Henning; Erwin, Steven C.; Galazka, Zbigniew; Korytov, Maxym; Albrecht, Martin; Uecker, Reinhard; Fornari, Roberto

    2012-10-22

    A single phase InN epitaxial film is grown on a bulk In{sub 2}O{sub 3}(111) wafer by plasma-assisted molecular beam epitaxy. The InN/In{sub 2}O{sub 3} orientation relationship is found to be (0001) parallel (111) and [1100] parallel [112]. High quality of the layer is confirmed by the small widths of the x-ray rocking curves, the sharp interfaces revealed by transmission electron microscopy, the narrow spectral width of the Raman E{sub 2}{sup h} vibrational mode, and the position of the photoluminescence band close to the fundamental band gap of InN.

  14. Band alignment of InN/6H-SiC heterojunction determined by x-ray photoelectron spectroscopy

    SciTech Connect

    Jing, Qiang; Wu, Guoguang; Zhang, Yuantao; Gao, Fubin; Cai, Xupu; Zhao, Yang; Li, Wancheng Du, Guotong

    2014-08-11

    The valence band offset (VBO) of InN/6H-SiC heterojunction has been directly measured by x-ray photoelectron spectroscopy. The VBO is determined to be −0.10 ± 0.23 eV and the conduction band offset is deduced to be −2.47 ± 0.23 eV, indicating that the heterojunction has a type-II band alignment. The accurate determination of the valence and conduction band offsets is important for applications and analysis of InN/6H-SiC optoelectronic devices.

  15. Morphology and composition controlled growth of polar c-axis and nonpolar m-axis well-aligned ternary III-nitride nanotube arrays

    NASA Astrophysics Data System (ADS)

    Li, Huijie; Zhao, Guijuan; Kong, Susu; Han, Dongyue; Wei, Hongyuan; Wang, Lianshan; Chen, Zhen; Yang, Shaoyan

    2015-10-01

    Control over the nanostructure morphology and growth orientation is in high demand for fundamental research and technological applications. Herein we report a general strategy to fabricate polar c-axis and nonpolar m-axis well-aligned III-nitride ternary nanotube arrays with controllable morphologies and compositions. By depositing AlN on the InN nanorod array templates and thermally removing the InN templates, InAlN nanotubes can be obtained. Polar c-axis and nonpolar m-axis nanotubes were formed on the c- and r-plane sapphire substrates, respectively. The nanotubes are single crystalline and highly ordered on the substrates, as revealed by X-ray diffraction, electron microscopy, and selected area electron microscopy characterization. It was found that the In droplets on top of the InN nanorods play a critical role in controlling the morphology of the nanotubes. By keeping or removing the In droplets, the obtained nanotubes exhibited both ends open or only one end open. And by varying the AlN deposition temperature, the In composition in the nanotubes can be changed from 0 to 0.29. The nanotube synthesis method is simple and can be applied to the formation of other III-nitride ternary (InGaN, and AlGaN) or quaternary (InAlGaN) alloy nanotube arrays.Control over the nanostructure morphology and growth orientation is in high demand for fundamental research and technological applications. Herein we report a general strategy to fabricate polar c-axis and nonpolar m-axis well-aligned III-nitride ternary nanotube arrays with controllable morphologies and compositions. By depositing AlN on the InN nanorod array templates and thermally removing the InN templates, InAlN nanotubes can be obtained. Polar c-axis and nonpolar m-axis nanotubes were formed on the c- and r-plane sapphire substrates, respectively. The nanotubes are single crystalline and highly ordered on the substrates, as revealed by X-ray diffraction, electron microscopy, and selected area electron microscopy

  16. Oxidation state, aggregation, and heterolytic dissociation of allyl indium reagents.

    PubMed

    Koszinowski, Konrad

    2010-05-05

    Solutions of allyl indium reagents formed in the reactions of indium with allyl bromide and allyl iodide, respectively, in N,N-dimethylformamide, tetrahydrofuran, and water were analyzed by a combination of electrospray-ionization mass spectrometry, temperature-dependent (1)H NMR spectroscopy, and electrical conductivity measurements. Additional mass spectrometric experiments probed charge-tagged derivatives of the allyl indium reagents. The results obtained indicate the presence of allyl indium(+3) species, which undergo heterolytic dissociation to yield ions such as InR(2)(solv)(+) and InRX(3)(-) with R = allyl and X = Br and I. The extent of dissociation is greatest for N,N-dimethylformamide, whereas aggregation effects are more pronounced for the less polar tetrahydrofuran. The heterolytic dissociation of the allyl indium reagents supposedly enhances their reactivity by simultaneously providing highly Lewis acidic allyl indium cations and nucleophilic allyl indate anions.

  17. Indium Alloy as Cadmium Brush Plating Replacement

    DTIC Science & Technology

    2010-06-17

    Aged In- Sn Aged Cd In- Sn before Aging Cd before Aging Sn -Zn (12V) before Aging 18 Temperature Cycling Table 6. Temperature Cycling Conditions for Each...selection Key Requirements Candidate Cd Plating Replacement Processing Al Zn Ni Sn Zn-Ni Sn -Ni Sn -Zn Sn -In Meet Environmental Health and Safety (EHS...Corrosion Protection P P F P ? ? P P Whisker Growth (FOR INFO) ? F P F P P ? ? Al = Aluminum; In = Indium; Ni = Nickel; Sn =

  18. Prevention of indium intoxication by ferric dextran

    PubMed Central

    Gabbiani, G.; Selye, H.; Tuchweber, Beatriz

    1962-01-01

    Experiments on the rat indicate that intravenous administration of indium chloride produces severe hepatic necroses with fatal icterus within a few days. These actions can be prevented by the prophylactic administration of ferric dextran. This protective effect of the iron compound must be largely specific since it could not be duplicated by pretreatment with any of a large series of other agents. The possible mechanism of the protective effect is briefly discussed. ImagesFig. 1 PMID:13945982

  19. Indium 111 toxicity in the human lymphocyte

    SciTech Connect

    Silberstein, E.B.; Watson, S.; Mayfield, G.; Kereiakes, J.G.; Bullock, W.

    1985-05-01

    Indium-labeled lymphocytes were examined for response to a variety of mitogens, ability to synthesize immunoglobulins, mitotic index, and presence of chromosome aberrations at a range of exposures from 0.2 to 500 muCi/10(8) cells. Results of all four tests were found to be abnormal when the lymphocytes were labeled with /sup 111/In activities well within those employed for diagnostic testing.

  20. A Dance Class, a Drag King, & the Pedagogical Possibilities of Performative Hip-Hop: An Interview with Carmen Morrison & Alex U. Inn

    ERIC Educational Resources Information Center

    Schönfeldt-Aultman, Scott M.; Morrison, Carmen

    2015-01-01

    Alex U. Inn is the co-founder and one of the two MCs of the hip-hop drag king group, Momma's Boyz. Momma's Boyz celebrated their tenth anniversary in 2014. Carmen Morrison is the offstage name of Alex U. Inn, though "Carmen" now goes by Alex offstage, as well. Within this interview, the names "Carmen" and "Alex" are…

  1. A Dance Class, a Drag King, & the Pedagogical Possibilities of Performative Hip-Hop: An Interview with Carmen Morrison & Alex U. Inn

    ERIC Educational Resources Information Center

    Schönfeldt-Aultman, Scott M.; Morrison, Carmen

    2015-01-01

    Alex U. Inn is the co-founder and one of the two MCs of the hip-hop drag king group, Momma's Boyz. Momma's Boyz celebrated their tenth anniversary in 2014. Carmen Morrison is the offstage name of Alex U. Inn, though "Carmen" now goes by Alex offstage, as well. Within this interview, the names "Carmen" and "Alex" are…

  2. III-nitride ultraviolet emitters produced by molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, Anirban

    In this dissertation, the growth of III-Nitride based ultraviolet (UV) emitters by molecular beam epitaxy has been addressed. These devices can find applications in optical data storage, solid-state lighting, and in biological detection. A significant part of the research involved materials development, as there are several major scientific and technological hurdles that must be overcome in order to produce commercially viable devices. For emission in the wavelength region 330 nm to 350 nm, the devices were designed as electrically-injected light emitting diodes (LEDs). Each layer of this structure was individually optimized to improve the materials properties. To overcome the difficulties in p-type doping, a new growth regime has been explored which led to films with hole concentrations of up to 2 x 10 18/cm3. Multiple quantum wells (MQWs) were grown along polar and non-polar directions to understand the effects of the presence of built-in polarization fields. It was found that these detrimental effects are minimized for ultra thin wells. Use of an Indium flux as a surfactant was found to substantially improve the luminescence properties of bulk Aluminum Gallium Nitride (AlGaN) alloys and MQWs. UV-LEDs grown under these optimized conditions show an optical power output of 0.75 mW at 340 nm and 4.5 mW at 350nm. For emission in the wavelength region below 270 nm, due to the difficulty of doping AlGaN alloys with high Aluminum Nitride (AlN) mole fraction, edge or vertical emitting electron beam-pumped laser structures have been developed. Since it is difficult to cleave III-Nitrides deposited onto C-plane sapphire, edge emitting laser structures using a Graded-Index Separate Confinement Heterostructure (GRINSCH) based geometry have been deposited onto A-plane sapphire using a novel AlN buffer layer. An AlGaN bulk film or a set of AlN/AlGaN MQWs is used as the active region. For use in these devices, the growth of high Al content AlGaN was optimized to reduce the deep

  3. Polarization Effects in Group III-Nitride Materials and Devices

    NASA Astrophysics Data System (ADS)

    Wei, Qiyuan

    Group III-nitride semiconductors have wide application in optoelectronic devices. Spontaneous and piezoelectric polarization effects have been found to be critical for electric and optical properties of group III-nitrides. In this dissertation, firstly, the crystal orientation dependence of the polarization is calculated and in-plane polarization is revealed. The in-plane polarization is sensitive to the lateral characteristic dimension determined by the microstructure. Specific semi-polar plane growth is suggested for reducing quantum-confined Stark effect. The macroscopic electrostatic field from the polarization discontinuity in the heterostructures is discussed, b ased on that, the band diagram of InGaN/GaN quantum well/barrier and AlGaN/GaN heterojunction is obtained from the self-consistent solution of Schrodinger and Poisson equations. New device design such as triangular quantum well with the quenched polarization field is proposed. Electron holography in the transmission electron microscopy is used to examine the electrostatic potential under polarization effects. The measured potential energy profiles of heterostructure are compared with the band simulation, and evidences of two-dimensional hole gas (2DHG) in a wurtzite AlGaN/ AlN/ GaN superlattice, as well as quasi two-dimensional electron gas (2DEG) in a zinc-blende AlGaN/GaN are found. The large polarization discontinuity of AlN/GaN is the main source of the 2DHG of wurtzite nitrides, while the impurity introduced during the growth of AlGaN layer provides the donor states that to a great extent balance the free electrons in zinc-blende nitrides. It is also found that the quasi-2DEG concentration in zinc-blende AlGaN/GaN is about one order of magnitude lower than the wurtzite AlGaN/GaN, due to the absence of polarization. Finally, the InAlN/GaN lattice-matched epitaxy, which ideally has a zero piezoelectric polarization and strong spontaneous polarization, is experimentally studied. The breakdown in

  4. Process for making transition metal nitride whiskers

    DOEpatents

    Bamberger, C.E.

    1988-04-12

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

  5. Process for making transition metal nitride whiskers

    DOEpatents

    Bamberger, Carlos E.

    1989-01-01

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

  6. Silicon nitride/silicon carbide composite powders

    DOEpatents

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

    1996-06-11

    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.

  7. The toxicology of indium tin oxide.

    PubMed

    Bomhard, Ernst M

    2016-07-01

    Indium tin oxide (ITO) is a technologically important semiconductor. An increasing number of cases of severe lung effects (characterized by pulmonary alveolar proteinosis and/or interstitial fibrosis) in ITO-exposed workers warrants a review of the toxicological hazards. Short- and long-term inhalation studies in rats and mice revealed persistent alveolar proteinosis, inflammation and fibrosis in the lungs down to concentrations as low as 0.01mg/m(3). In rats, the incidences of bronchiolo-alveolar adenomas and carcinomas were significantly increased at all concentrations. In mice, ITO was not carcinogenic. A few bronchiolo-alveolar adenomas occurring after repeated intratracheal instillation of ITO to hamsters have to be interpreted as treatment-related. In vitro and in vivo studies on the formation of reactive oxygen species suggest epigenetic effects as cause of the lung tumor development. Repeated intratracheal instillation of ITO to hamsters slightly affected the male sexual organs, which might be interpreted as a secondary effect of the lung damage. Epidemiological and medical surveillance studies, serum/blood indium levels in workers as well as data on the exposure to airborne indium concentrations indicate a need for measures to reduce exposure at ITO workplaces. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Thermoelectric Properties of Indium-Filled Skutterudites

    SciTech Connect

    He, Tao; Chen, Jiazhong; Rosenfeld, H. David; Subramanian, M.A.

    2008-09-18

    Structural, electrical, and thermal transport properties of CoSb{sub 3} partially filled with indium are reported. Polycrystalline samples of In{sub x}Co{sub 4}Sb{sub 12} (0 {le} x {le} 0.3) were prepared by solid-state reaction under a gas mixture of 5% H{sub 2} and 95% Ar. The solubility limit of the indium filling voids in CoSb{sub 3} was found to be close to 0.22. Synchrotron X-ray diffraction refinement of the x = 0.2 sample showed that the indium is located in the classic rattler site and has a substantially larger thermal factor than those of Co and Sb. The electrical resistivity, Seebeck coefficients, and thermal conductivity of the In{sub x}Co{sub 4}Sb{sub 12} samples were measured in the temperature range of 300-600 K. All samples showed metal-like behavior, and the large negative Seebeck coefficients indicated n-type conduction. The thermal conductivity decreased with increasing temperature for all samples. A thermoelectric figure-of-merit (ZT) {ge} 1 (n-type) has been achieved when x {ge} 0.2 in In{sub x}Co{sub 4}Sb{sub 12} at 575 K.

  9. Enhanced memory effect via quantum confinement in 16 nm InN nanoparticles embedded in ZnO charge trapping layer

    SciTech Connect

    El-Atab, Nazek; Nayfeh, Ammar; Cimen, Furkan; Alkis, Sabri; Ortaç, Bülend; Alevli, Mustafa; Dietz, Nikolaus; Okyay, Ali K.

    2014-06-23

    In this work, the fabrication of charge trapping memory cells with laser-synthesized indium-nitride nanoparticles (InN-NPs) embedded in ZnO charge trapping layer is demonstrated. Atomic layer deposited Al{sub 2}O{sub 3} layers are used as tunnel and blocking oxides. The gate contacts are sputtered using a shadow mask which eliminates the need for any lithography steps. High frequency C-V{sub gate} measurements show that a memory effect is observed, due to the charging of the InN-NPs. With a low operating voltage of 4 V, the memory shows a noticeable threshold voltage (V{sub t}) shift of 2 V, which indicates that InN-NPs act as charge trapping centers. Without InN-NPs, the observed memory hysteresis is negligible. At higher programming voltages of 10 V, a memory window of 5 V is achieved and the V{sub t} shift direction indicates that electrons tunnel from channel to charge storage layer.

  10. Efficiency droop in indium gallium nitride light emitters: An introduction to photon quenching processes

    NASA Astrophysics Data System (ADS)

    Sarkissian, Raymond

    This thesis contains work from two separate projects, a study of the efficiency of light emitting diodes, and a tapered-fiber approach to photonic crystal integrated photonics. The first part of this thesis describes an experimental investigation of the quantum efficiency of InGaN-based light emitters. Blue and Green LEDs that utilize InGaN quantum wells for their active medium suffer from a reduction in efficiency with increasing bias. This phenomenon is called efficiency droop. In this thesis experimental evidence for significant quenching of photon population in InGaN is presented and its relevance to the efficiency droop problem in InGaN-based light emitting structures is discussed. An equilibrium rate equation model is set up to demonstrate that radiative efficiency for this loss mechanism not only has a similar dependence on carrier density as Auger recombination process, but it also possesses the right order of magnitude making it difficult to distinguish between the two and possibly leading to errors in interpretation. The impact of photon quenching processes on device performance is emphasized by demonstrating loss of efficiency for spectral regions where there is experimental evidence for photon quenching. We have observed this phenomenon for both c-plane and m-plane light emitting structures. Both structures exhibit droop-like behavior for spectral regions where there is evidence for photon quenching. We have also observed and characterized the dynamical Stark effect for an m-plane light emitter considered in this manuscript. Our results revealed localization centers with a corresponding band-edge energy of 388nm and an excitonic binding energy of 17.81mev. Furthermore, fabrication of a photonic crystal waveguide fiber taper coupler is demonstrated with a peak coupling efficiency of 97 %. All four ports of the device are accessible providing an opportunity for investigation of simultaneous interaction of different light sources inside the photonic crystal cavity. A numerical model is set forth to analyze such devices with an excellent agreement with the experimental data. One important result of that theory is the ability to experimentally extract the phase contribution of optical resonators that employ periodic structures such as photonic crystal cavities. This device has also been used to demonstrate all-optical nonlinear shift and bleaching of cavity resonances via non-degenerate two photon absorption, non-degenerate Kerr mechanism, free carrier absorption, and free carrier plasma effects. As the response time of two photon processes are very fast, about 10 fs, this device can be used in ultrafast low energy all optical switching applications.

  11. Efficiency Improvement of Nitride-Based Solid State Light Emitting Materials -- CRADA Final Report

    SciTech Connect

    Kisielowski, Christian; Weber, Eicke

    2010-05-13

    The development of In{sub x}Ga{sub 1-x} N/GaN thin film growth by Molecular Beam Epitaxy has opened a new route towards energy efficient solid-state lighting. Blue and green LED's became available that can be used to match the whole color spectrum of visible light with the potential to match the eye response curve. Moreover, the efficiency of such devices largely exceeds that of incandescent light sources (tungsten filaments) and even competes favorably with lighting by fluorescent lamps. It is, however, also seen in Figure 1 that it is essential to improve on the luminous performance of green LED's in order to mimic the eye response curve. This lack of sufficiently efficient green LED's relates to particularities of the In{sub x}Ga{sub 1-x}N materials system. This ternary alloy system is polar and large strain is generated during a lattice mismatched thin film growth because of the significantly different lattice parameters between GaN and InN and common substrates such as sapphire. Moreover, it is challenging to incorporate indium into GaN at typical growth temperatures because a miscibility gap exists that can be modified by strain effects. As a result a large parameter space needs exploration to optimize the growth of In{sub x}Ga{sub 1-x}N and to date it is unclear what the detailed physical processes are that affect device efficiencies. In particular, an inhomogeneous distribution indium in GaN modifies the device performance in an unpredictable manner. As a result technology is pushed forward on a trial and error basis in particular in Asian countries such as Japan and Korea, which dominate the market and it is desirable to strengthen the competitiveness of the US industry. This CRADA was initiated to help Lumileds Lighting/USA boosting the performance of their green LED's. The tasks address the distribution of the indium atoms in the active area of their blue and green LED's and its relation to internal and external quantum efficiencies. Procedures to

  12. Growth, Fabrication, and Characterization of Continuous-Wave Aluminum Gallium Nitride -Cladding-Free m-plane Indium Gallium Nitride / Gallium Nitride Laser Diodes

    NASA Astrophysics Data System (ADS)

    Farrell, Robert Michael

    Many applications exist for InGaN/GaN laser diodes (LDs), including high-density optical data storage, laser-based projection displays, high-resolution laser printing, solid-state lighting, medical diagnostics, and chemical sensing. Although device performance continues to improve, current commercially-available InGaN/GaN LDs are still grown on the (0001) c-plane of the wurtzite crystal structure and their performance is nonetheless affected by the presence of polarization-related electric fields. As an alternative to conventional c-plane technologies, growth of InGaN/GaN LDs on nonpolar or semipolar orientations presents a viable approach to reducing or eliminating the issues associated with polarization-related electric fields. Despite these potential advantages, though, the lowest reported threshold current densities for nonpolar and semipolar LDs are still about 2 to 3 times higher than those reported for c-plane LDs. In this thesis, we discuss the growth, fabrication, and characterization of continuous-wave AlGaN-cladding-free (ACF) m-plane LDs with performance that is comparable to the best state-of-the-art c-plane LDs. In the first part of this thesis, the characterization of low-defect-density m-plane thin films and devices grown by metalorganic chemical vapor deposition is presented. The physical origin of the four-sided pyramidal hillocks commonly observed on m-plane thin films is identified and an understanding of these mechanisms is used to explain the impact of carrier gas and substrate misorientation on the morphological, structural, and optical properties of m-plane thin films and devices. In the second part of this thesis, several aspects of the development of a quick, self-aligned LD fabrication process are discussed. These include the implementation of relatively conventional fabrication technologies for routine device processing as well as the development of innovative approaches for improving the accuracy and reproducibility of facet cleaving and ridge waveguide etching processes. Finally, in the third and last part of this thesis, the performance of ACF m-plane LDs with threshold current densities of 1.54 kA/cm2 and peak output powers of 1.6 W is discussed. The transparency carrier density of these devices is estimated to be 4.9 x 10 18 cm-3, which is lower than typical transparency carrier densities reported or even calculated for c-plane GaN-based LDs and comparable to typical transparency carrier densities reported for GaAs- and InP-based LDs.

  13. Strain effect in group-III nitride semiconductors and their alloys

    NASA Astrophysics Data System (ADS)

    Yan, Qimin; Rinke, Patrick; Scheffler, Matthias; van de Walle, Chris

    2009-11-01

    Strain plays a crucial role in group-III nitride semiconductor based devices since it affects the band structure near the valence- and conduction-band edges and thus the optical properties and the device characteristics. However, the deformation potentials that describe the change in band structure under strain have not yet been reliably determined. We present a systematic study of the strain effects in AlN, GaN and InN in the wurtzite phase. We apply density functional theory and hybrid functionals to address the band-gap problem. We observe nonlinearities of transition energies under realistic strain condition that may, in part, explain the appreciable scatter in previous theoretical work on deformation potentials of group-III-nitrides. For the linear regime around the experimental lattice parameters, we present a complete set of deformation potentials. Applying our deformation potentials, we study strain effects in InGaN alloys (including c-, m-, and semi-polar planes) grown on GaN substrates. We make predictions for the transition energies in these systems and their dependence on In composition.

  14. Theoretical Compton profile of diamond, boron nitride and carbon nitride

    NASA Astrophysics Data System (ADS)

    Aguiar, Julio C.; Quevedo, Carlos R.; Gomez, José M.; Di Rocco, Héctor O.

    2017-09-01

    In the present study, we used the generalized gradient approximation method to determine the electron wave functions and theoretical Compton profiles of the following super-hard materials: diamond, boron nitride (h-BN), and carbon nitride in its two known phases: βC3N4 and gC3N4 . In the case of diamond and h-BN, we compared our theoretical results with available experimental data. In addition, we used the Compton profile results to determine cohesive energies and found acceptable agreement with previous experiments.

  15. InP (Indium Phosphide): Into the future

    NASA Technical Reports Server (NTRS)

    Brandhorst, Henry W., Jr.

    1989-01-01

    Major industry is beginning to be devoted to indium phosphide and its potential applications. Key to these applications are high speed and radiation tolerance; however the high cost of indium phosphide may be an inhibitor to progress. The broad applicability of indium phosphide to many devices will be discussed with an emphasis on photovoltaics. Major attention is devoted to radiation tolerance and means of reducing cost of devices. Some of the approaches applicable to solar cells may also be relevant to other devices. The intent is to display the impact of visionary leadership in the field and enable the directions and broad applicability of indium phosphide.

  16. Method to Improve Indium Bump Bonding via Indium Oxide Removal Using a Multi-Step Plasma Process

    NASA Technical Reports Server (NTRS)

    Greer, H. Frank (Inventor); Jones, Todd J. (Inventor); Vasquez, Richard P. (Inventor); Hoenk, Michael E. (Inventor); Dickie, Matthew R. (Inventor); Nikzad, Shouleh (Inventor)

    2012-01-01

    A process for removing indium oxide from indium bumps in a flip-chip structure to reduce contact resistance, by a multi-step plasma treatment. A first plasma treatment of the indium bumps with an argon, methane and hydrogen plasma reduces indium oxide, and a second plasma treatment with an argon and hydrogen plasma removes residual organics. The multi-step plasma process for removing indium oxide from the indium bumps is more effective in reducing the oxide, and yet does not require the use of halogens, does not change the bump morphology, does not attack the bond pad material or under-bump metallization layers, and creates no new mechanisms for open circuits.

  17. Graphene on hexagonal boron nitride

    NASA Astrophysics Data System (ADS)

    Yankowitz, Matthew; Xue, Jiamin; LeRoy, B. J.

    2014-07-01

    The field of graphene research has developed rapidly since its first isolation by mechanical exfoliation in 2004. Due to the relativistic Dirac nature of its charge carriers, graphene is both a promising material for next-generation electronic devices and a convenient low-energy testbed for intrinsically high-energy physical phenomena. Both of these research branches require the facile fabrication of clean graphene devices so as not to obscure its intrinsic physical properties. Hexagonal boron nitride has emerged as a promising substrate for graphene devices as it is insulating, atomically flat and provides a clean charge environment for the graphene. Additionally, the interaction between graphene and boron nitride provides a path for the study of new physical phenomena not present in bare graphene devices. This review focuses on recent advancements in the study of graphene on hexagonal boron nitride devices from the perspective of scanning tunneling microscopy with highlights of some important results from electrical transport measurements.

  18. Nitride tuning of lanthanide chromites.

    PubMed

    Black, Ashley P; Johnston, Hannah E; Oró-Solé, Judith; Bozzo, Bernat; Ritter, Clemens; Frontera, Carlos; Attfield, J Paul; Fuertes, Amparo

    2016-03-21

    LnCrO(3-x)N(x) perovskites with Ln = La, Pr and Nd and nitrogen contents up to x = 0.59 have been synthesised through ammonolysis of LnCrO4 precursors. These new materials represent one of the few examples of chromium oxynitrides. Hole-doping through O(2-)/N(3-) anion substitution suppresses the magnetic transition far less drastically than Ln(3+)/M(2+) (M = Ca, Sr) cation substitutions because of the greater covalency of metal-nitride bonds. Hence, nitride-doping is a more benign method for doping metal oxides without suppressing electronic transitions.

  19. Precipitation of metal nitrides from chloride melts

    SciTech Connect

    Slater, S.A.; Miller, W.E.; Willit, J.L.

    1996-12-31

    Precipitation of actinides, lanthanides, and fission products as nitrides from molten chloride melts is being investigated for use as a final cleanup step in treating radioactive salt wastes generated by electrometallurgical processing of spent nuclear fuel. The radioactive components (eg, fission products) need to be removed to reduce the volume of high-level waste that requires disposal. To extract the fission products from the salt, a nitride precipitation process is being developed. The salt waste is first contacted with a molten metal; after equilibrium is reached, a nitride is added to the metal phase. The insoluble nitrides can be recovered and converted to a borosilicate glass after air oxidation. For a bench-scale experimental setup, a crucible was designed to contact the salt and metal phases. Solubility tests were performed with candidate nitrides and metal nitrides for which there are no solubility data. Experiments were performed to assess feasibility of precipitation of metal nitrides from chloride melts.

  20. Theoretical Study of Material and Device Properties of Group-III Nitrides

    NASA Astrophysics Data System (ADS)

    Yan, Qimin

    Group-III nitride semiconductors, including AlN, GaN, InN, and their alloys, are ideal materials for solid state lighting applications. Current research focuses on improving the efficiency by improvements in materials quality and novel device designs, for instance based on nonpolar and semipolar growth. The motivation for our work is to assist and guide the experimental development of high-performance solid state optoelectronic devices by performing computational studies. Our investigations range from basic structural and electronic properties of nitrides to the effects of device design on efficiency of light emission. In the area of fundamental properties, we performed a systematic study of strain effects on the electronic band structures of the group-III-nitrides (AlN, GaN and InN) using density-functional theory with an advanced hybrid functional as well as using the quasiparticle GW method. We present a complete set of deformation potentials that allows us to predict the band positions of group-III nitrides and their alloys (InGaN and AlGaN) under realistic strain conditions. We then employed the resulting first-principles deformation potentials to predict the effects of strain on transition energies and valence-band structures of c-plane, nonpolar, and semipolar InGaN alloy layers grown on GaN substrates, with particular attention to the role of strain in the polarized light emission. We also investigated the role of native defects in the optical properties of GaN and AlN, again using hybrid density-functional calculations. We established that complexes between Mg and nitrogen vacancies lead to the broad red luminescence that has often been observed in GaN. We find that isolated nitrogen vacancies can give rise to broad emission peaked at 2.18 eV. We show that isolated aluminum vacancies lead to an absorption peak at 3.43 eV and an emission peak at 2.73 eV. We also find that the complexes can give rise to absorption peaked at 3.97 eV and

  1. Generation of ultra-small InN nanocrystals by pulsed laser ablation of suspension in organic solution

    NASA Astrophysics Data System (ADS)

    Kurşungöz, Canan; Uzcengiz Şimşek, Elif; Tuzaklı, Refik; Ortaç, Bülend

    2017-03-01

    Nanostructures of InN have been extensively investigated since nano-size provides a number of advantages allowing applications in nanoscale electronic and optoelectronic devices. It is quite important to obtain pure InN nanocrystals (InN-NCs) to reveal the characteristic features, which gain interest in the literature. Here, we proposed a new approach for the synthesis of ultra-small hexagonal InN-NCs by using suspension of micron-sized InN powder in ethanol with pulsed laser ablation method. The liquid environment, laser energy and ablation time were optimized and a post-synthesis treatment, centrifugation, was performed to achieve InN-NCs with the smallest size. Besides, the micron-sized InN powder suspension, as a starting material, enabled us to obtain InN-NCs having diameters smaller than 5 nm. We also presented a detailed characterization of InN-NCs and demonstrated that the formation mechanism mainly depends on the fragmentation due to laser irradiation of the suspension.

  2. Site-controlled crystalline InN growth from the V-pits of a GaN substrate

    NASA Astrophysics Data System (ADS)

    Kuo, Chien-Ting; Hsu, Lung-Hsing; Lai, Yung-Yu; Cheng, Shan-Yun; Kuo, Hao-Chung; Lin, Chien-Chung; Cheng, Yuh-Jen

    2017-05-01

    A site-controlled crystalline InN growth from the V-pits of a GaN substrate was investigated. The V- pits were fabricated by epitaxial lateral growth of GaN over SiO2 disks patterned on a sapphire substrate. InN crystals were found to preferably grow on the inclined {10-11} crystal planes of the V-pits. A V-pit size of 1 μm or less can provide precise site-controlled InN nucleation at the V-pit bottom, while no InN was grown on the rest of the exposed GaN surfaces. The site-controlled nucleation is attributed to the low surface energy point created by the converging six {10-11} crystal facets at the V-pit bottom. When In source supply is below a certain value, this V-pit bottom is the only location able to aggregate enough active sources to start nucleation, thereby providing site-controlled crystal growth.

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

    SciTech Connect

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

    2015-11-09

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

  4. Boron Nitride Nanoribbons from Exfoliation of Boron Nitride Nanotubes

    NASA Technical Reports Server (NTRS)

    Hung, Ching-Cheh; Hurst, Janet; Santiago, Diana

    2017-01-01

    Two types of boron nitride nanotubes (BNNTs) were exfoliated into boron nitride nanoribbons (BNNR), which were identified using transmission electron microscopy: (1) commercial BNNTs with thin tube walls and small diameters. Tube unzipping was indicated by a large decrease of the sample's surface area and volume for pores less than 2 nm in diameter. (2) BNNTs with large diameters and thick walls synthesized at NASA Glenn Research Center. Here, tube unraveling was indicated by a large increase in external surface area and pore volume. For both, the exfoliation process was similar to the previous reported method to exfoliate commercial hexagonal boron nitride (hBN): Mixtures of BNNT, FeCl3, and NaF (or KF) were sequentially treated in 250 to 350 C nitrogen for intercalation, 500 to 750 C air for exfoliation, and finally HCl for purification. Property changes of the nanosized boron nitride throughout this process were also similar to the previously observed changes of commercial hBN during the exfoliation process: Both crystal structure (x-ray diffraction data) and chemical properties (Fourier-transform infrared spectroscopy data) of the original reactant changed after intercalation and exfoliation, but most (not all) of these changes revert back to those of the reactant once the final, purified products are obtained.

  5. Homogeneous dispersion of gallium nitride nanoparticles in a boron nitride matrix by nitridation with urea.

    PubMed

    Kusunose, Takafumi; Sekino, Tohru; Ando, Yoichi

    2010-07-01

    A Gallium Nitride (GaN) dispersed boron nitride (BN) nanocomposite powder was synthesized by heating a mixture of gallium nitrate, boric acid, and urea in a hydrogen atmosphere. Before heat treatment, crystalline phases of urea, boric acid, and gallium nitrate were recognized, but an amorphous material was produced by heat treatment at 400 degrees C, and then was transformed into GaN and turbostratic BN (t-BN) by further heat treatment at 800 degrees C. TEM obsevations of this composite powder revealed that single nanosized GaN particles were homogeneously dispersed in a BN matrix. Homogeneous dispersion of GaN nanoparticles was thought to be attained by simultaneously nitriding gallium nitrate and boric acid to GaN and BN with urea.

  6. J/{psi} production in indium-indium collisions at SPS energies

    SciTech Connect

    Pillot, P.; Ducroux, L.; Guichard, A.; Tieulent, R.; Arnaldi, R.; Colla, A.; Cortese, P.; Ferretti, A.; Oppedisano, C.; Scomparin, E.; Averbeck, R.; Drees, A.; Banicz, K.; Keil, M.; Castor, J.; Devaux, A.; Force, P.; Manso, F.; Chaurand, B.; Cicalo, C.

    2006-01-12

    The NA60 experiment collected data on dimuon production in indium-indium collisions at 158 GeV/c per incident nucleon, in year 2003, to contribute to the clarification of several questions raised by previous experiments studying high-energy heavy-ion physics at the CERN SPS in search of the quark gluon plasma. Among these previous results stands the observation, by NA50, that the production yield of J/{psi} mesons is suppressed in central Pb-Pb collisions beyond the normal nuclear absorption defined by proton-nucleus data. By comparing the centrality dependence of the suppression pattern between different colliding systems, S-U, Pb-Pb and In-In, we should be able to identify the corresponding scaling variable, and the physics mechanism driving the suppression. In this paper, we will present the ratio of J/{psi} and Drell-Yan production cross-sections in indium-indium collisions, in three centrality bins, and how these values compare to previous measurements. We will also present a study of the transverse momentum distributions of the J/{psi} mesons, in seven centrality bins.

  7. Advanced Computational Modeling of Vapor Deposition in a High-Pressure Reactor

    NASA Technical Reports Server (NTRS)

    Cardelino, Beatriz H.; Moore, Craig E.; McCall, Sonya D.; Cardelino, Carlos A.; Dietz, Nikolaus; Bachmann, Klaus

    2004-01-01

    In search of novel approaches to produce new materials for electro-optic technologies, advances have been achieved in the development of computer models for vapor deposition reactors in space. Numerical simulations are invaluable tools for costly and difficult processes, such as those experiments designed for high pressures and microgravity conditions. Indium nitride is a candidate compound for high-speed laser and photo diodes for optical communication system, as well as for semiconductor lasers operating into the blue and ultraviolet regions. But InN and other nitride compounds exhibit large thermal decomposition at its optimum growth temperature. In addition, epitaxy at lower temperatures and subatmospheric pressures incorporates indium droplets into the InN films. However, surface stabilization data indicate that InN could be grown at 900 K in high nitrogen pressures, and microgravity could provide laminar flow conditions. Numerical models for chemical vapor deposition have been developed, coupling complex chemical kinetics with fluid dynamic properties.

  8. Advanced Computational Modeling of Vapor Deposition in a High-pressure Reactor

    NASA Technical Reports Server (NTRS)

    Cardelino, Beatriz H.; Moore, Craig E.; McCall, Sonya D.; Cardelino, Carlos A.; Dietz, Nikolaus; Bachmann, Klaus

    2004-01-01

    In search of novel approaches to produce new materials for electro-optic technologies, advances have been achieved in the development of computer models for vapor deposition reactors in space. Numerical simulations are invaluable tools for costly and difficult processes, such as those experiments designed for high pressures and microgravity conditions. Indium nitride is a candidate compound for high-speed laser and photo diodes for optical communication system, as well as for semiconductor lasers operating into the blue and ultraviolet regions. But InN and other nitride compounds exhibit large thermal decomposition at its optimum growth temperature. In addition, epitaxy at lower temperatures and subatmospheric pressures incorporates indium droplets into the InN films. However, surface stabilization data indicate that InN could be grown at 900 K in high nitrogen pressures, and microgravity could provide laminar flow conditions. Numerical models for chemical vapor deposition have been developed, coupling complex chemical kinetics with fluid dynamic properties.

  9. Advanced Computational Modeling of Vapor Deposition in a High-Pressure Reactor

    NASA Technical Reports Server (NTRS)

    Cardelino, Beatriz H.; Moore, Craig E.; McCall, Sonya D.; Cardelino, Carlos A.; Dietz, Nikolaus; Bachmann, Klaus

    2004-01-01

    In search of novel approaches to produce new materials for electro-optic technologies, advances have been achieved in the development of computer models for vapor deposition reactors in space. Numerical simulations are invaluable tools for costly and difficult processes, such as those experiments designed for high pressures and microgravity conditions. Indium nitride is a candidate compound for high-speed laser and photo diodes for optical communication system, as well as for semiconductor lasers operating into the blue and ultraviolet regions. But InN and other nitride compounds exhibit large thermal decomposition at its optimum growth temperature. In addition, epitaxy at lower temperatures and subatmospheric pressures incorporates indium droplets into the InN films. However, surface stabilization data indicate that InN could be grown at 900 K in high nitrogen pressures, and microgravity could provide laminar flow conditions. Numerical models for chemical vapor deposition have been developed, coupling complex chemical kinetics with fluid dynamic properties.

  10. Advanced Computational Modeling of Vapor Deposition in a High-pressure Reactor

    NASA Technical Reports Server (NTRS)

    Cardelino, Beatriz H.; Moore, Craig E.; McCall, Sonya D.; Cardelino, Carlos A.; Dietz, Nikolaus; Bachmann, Klaus

    2004-01-01

    In search of novel approaches to produce new materials for electro-optic technologies, advances have been achieved in the development of computer models for vapor deposition reactors in space. Numerical simulations are invaluable tools for costly and difficult processes, such as those experiments designed for high pressures and microgravity conditions. Indium nitride is a candidate compound for high-speed laser and photo diodes for optical communication system, as well as for semiconductor lasers operating into the blue and ultraviolet regions. But InN and other nitride compounds exhibit large thermal decomposition at its optimum growth temperature. In addition, epitaxy at lower temperatures and subatmospheric pressures incorporates indium droplets into the InN films. However, surface stabilization data indicate that InN could be grown at 900 K in high nitrogen pressures, and microgravity could provide laminar flow conditions. Numerical models for chemical vapor deposition have been developed, coupling complex chemical kinetics with fluid dynamic properties.

  11. Tunable surface electron spin splitting with electric double-layer transistors based on InN.

    PubMed

    Yin, Chunming; Yuan, Hongtao; Wang, Xinqiang; Liu, Shitao; Zhang, Shan; Tang, Ning; Xu, Fujun; Chen, Zhuoyu; Shimotani, Hidekazu; Iwasa, Yoshihiro; Chen, Yonghai; Ge, Weikun; Shen, Bo

    2013-05-08

    Electrically manipulating electron spins based on Rashba spin-orbit coupling (SOC) is a key pathway for applications of spintronics and spin-based quantum computation. Two-dimensional electron systems (2DESs) offer a particularly important SOC platform, where spin polarization can be tuned with an electric field perpendicular to the 2DES. Here, by measuring the tunable circular photogalvanic effect (CPGE), we present a room-temperature electric-field-modulated spin splitting of surface electrons on InN epitaxial thin films that is a good candidate to realize spin injection. The surface band bending and resulting CPGE current are successfully modulated by ionic liquid gating within an electric double-layer transistor configuration. The clear gate voltage dependence of CPGE current indicates that the spin splitting of the surface electron accumulation layer is effectively tuned, providing a way to modulate the injected spin polarization in potential spintronic devices.

  12. Electron Accumulation Layers in InN Nanocolumns Studied by Raman Scattering

    SciTech Connect

    Gallardo, E.; Lazic, S.; Calleja, J. M.; Agullo-Rueda, F.; Grandal, J.; Sanchez-Garcia, M. A.; Calleja, E.

    2010-01-04

    Inelastic light scattering measurements on single crystal InN nanocolumns grown by plasma-assisted molecular beam epitaxy on both Si(001) and Si(111) substrates reveal the existence of a surface electron accumulation layer in the lateral non-polar sidewalls of the nanocolumns. Small and reversible electron density variations of this surface layer has been induced by chemical treatments of the nanocolumns, which can be accurately determined from the frequency of the LO phonon-plasmon coupled mode L{sub -}. The L{sub -} to E{sub 1}(LO) phonon intensity ratio dependence on the column diameter and the excitation wavelength is interpreted in terms of the inhomogeneous electron distribution in the nanocolumns volume and the presence of strong elastic light scattering by the nanocolumns. The TO modes fail to obey conventional selection rules, a fact that is also observed in GaN nanocolumns.

  13. Strain Relief Analysis of InN Quantum Dots Grown on GaN

    PubMed Central

    2007-01-01

    We present a study by transmission electron microscopy (TEM) of the strain state of individual InN quantum dots (QDs) grown on GaN substrates. Moiré fringe and high resolution TEM analyses showed that the QDs are almost fully relaxed due to the generation of a 60° misfit dislocation network at the InN/GaN interface. By applying the Geometric Phase Algorithm to plan-view high-resolution micrographs, we show that this network consists of three essentially non-interacting sets of misfit dislocations lying along the directions. Close to the edge of the QD, the dislocations curve to meet the surface and form a network of threading dislocations surrounding the system. PMID:21794190

  14. Solar hot water system installed at Quality Inn, Key West, Florida

    NASA Astrophysics Data System (ADS)

    1980-04-01

    The solar energy hot water system installed in the Quality Inn, Key West, Florida, which consists of four buildings is described. Three buildings are low-rise, two-story buildings containing 100 rooms. The fourth is a four-story building with 48 rooms. The solar system was designed to provide approximately 50 percent of the energy required for the domestic hot water system. The solar system consists of approximately 1400 square feet of flat plate collector, two 500 gallon storage tanks, a circulating pump, and a controller. Operation of the system was begun in April 1978, and has continued to date with only three minor interruptions for pump repair. In the first year of operation, it was determined that the use of the solar facility resulted in forty percent fuel savings.

  15. Solar hot water system installed at Quality Inn, Key West, Florida

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The solar energy hot water system installed in the Quality Inn, Key West, Florida, which consists of four buildings is described. Three buildings are low-rise, two-story buildings containing 100 rooms. The fourth is a four-story building with 48 rooms. The solar system was designed to provide approximately 50 percent of the energy required for the domestic hot water system. The solar system consists of approximately 1400 square feet of flat plate collector, two 500 gallon storage tanks, a circulating pump, and a controller. Operation of the system was begun in April 1978, and has continued to date with only three minor interruptions for pump repair. In the first year of operation, it was determined that the use of the solar facility resulted in forty percent fuel savings.

  16. Solar hot water system installed at Quality Inn, Key West, Florida. Final report

    SciTech Connect

    Not Available

    1980-04-01

    The solar energy hot water system installed in the Quality Inn, Key West, Florida, which consists of four buildings, is described. Three buildings are low-rise, two-story buildings containing 100 rooms. The fourth is a four-story building with 48 rooms. The solar system was designed to provide approximately 50% of the energy required for the domestic hot water system. The solar system consists of approximately 1400 ft/sup 2/ of flat plate collector, two 500 gal storage tanks, a circulating pump, and a controller. Operation of the system was begun in April 1978, and has continued to date with only three minor interruptions for pump repair. In the first year of operation, it was determined that the use of the solar facility resulted in 40% fuel savings.

  17. Temperature dependences of the contact resistivity in ohmic contacts to n{sup +}-InN

    SciTech Connect

    Sachenko, A. V.; Belyaev, A. E.; Boltovets, N. S.; Brunkov, P. N.; Jmerik, V. N.; Ivanov, S. V.; Kapitanchuk, L. M.; Konakova, R. V. Klad’ko, V. P.; Romanets, P. N.; Saja, P. O.; Safryuk, N. V.; Sheremet, V. N.

    2015-04-15

    The temperature dependences of the contact resistivity (ρ{sub c}) of ohmic contacts based on the Au-Ti-Pd-InN system are measured at an InN doping level of 2 × 10{sup 18} cm{sup −3} in the temperature range of 4.2–300 K. At temperatures T > 150 K, linearly increasing dependences ρ{sub c}(T) are obtained. The dependences are explained within the mechanism of thermionic current flow through metal shunts associated with dislocations. Good agreement between theoretical and experimental dependences is achieved assuming that the flowing current is limited by the total resistance of the metal shunts, and the density of conductive dislocations is ∼5 × 10{sup 9} cm{sup −2}. Using the X-ray diffraction method, the density of screw and edge dislocations in the structure under study is measured: their total density exceeds 10{sup 10} cm{sup −2}.

  18. Optical studies of MBE-grown InN nanocolumns: Evidence of surface electron accumulation

    NASA Astrophysics Data System (ADS)

    Segura-Ruiz, J.; Garro, N.; Cantarero, A.; Denker, C.; Malindretos, J.; Rizzi, A.

    2009-03-01

    Vertically self-aligned InN nanocolumns have been investigated by means of scanning electron microscopy, Raman scattering, and photoluminescence spectroscopy. Different nanocolumn morphologies corresponding to different molecular beam epitaxy growth conditions have been studied. Raman spectra revealed strain-free nanocolumns with high crystalline quality for the full set of samples studied. Longitudinal optical modes both uncoupled and coupled to an electron plasma coexist in the Raman spectra pointing to the existence of two distinctive regions in the nanocolumn: a surface layer of degenerated electrons and a nondegenerated inner core. The characteristics of the low-temperature photoluminescence and its dependence on temperature and excitation power can be explained by a model considering localized holes recombining with degenerated electrons close to the nonpolar surface. The differences observed in the optical response of different samples showing similar crystalline quality have been attributed to the variation in the electron accumulation layer with the growth conditions.

  19. Role of indium-111 chloride imaging in osteoid osteoma

    SciTech Connect

    Kumar, R.; Swischuk, L.E.; Schreiber, M.H.

    1986-10-01

    Indium-111 chloride imaging plays an important role in differentiating intracortical osteoid osteoma from chronic cortical abscess. The study also may be useful in the detection of intramedullary osteoid osteoma. Four patients who greatly benefited from indium-111 chloride imaging are presented.

  20. Two-Step Plasma Process for Cleaning Indium Bonding Bumps

    NASA Technical Reports Server (NTRS)

    Greer, Harold F.; Vasquez, Richard P.; Jones, Todd J.; Hoenk, Michael E.; Dickie, Matthew R.; Nikzad, Shouleh

    2009-01-01

    A two-step plasma process has been developed as a means of removing surface oxide layers from indium bumps used in flip-chip hybridization (bump bonding) of integrated circuits. The two-step plasma process makes it possible to remove surface indium oxide, without incurring the adverse effects of the acid etching process.

  1. Comparison of nonpolar III-nitride vertical-cavity surface-emitting lasers with tunnel junction and ITO intracavity contacts

    NASA Astrophysics Data System (ADS)

    Leonard, J. T.; Young, E. C.; Yonkee, B. P.; Cohen, D. A.; Shen, C.; Margalith, T.; Ng, T. K.; DenBaars, S. P.; Ooi, B. S.; Speck, J. S.; Nakamura, S.

    2016-02-01

    We report on the lasing of III-nitride nonpolar, violet, vertical-cavity surface-emitting lasers (VCSELs) with IIInitride tunnel-junction (TJ) intracavity contacts and ion implanted apertures (IIAs). The TJ VCSELs are compared to similar VCSELs with tin-doped indium oxide (ITO) intracavity contacts. Prior to analyzing device results, we consider the relative advantages of III-nitride TJs for blue and green emitting VCSELs. The TJs are shown to be most advantageous for violet and UV VCSELs, operating near or above the absorption edge for ITO, as they significantly reduce the total internal loss in the cavity. However, for longer wavelength III-nitride VCSELs, TJs primarily offer the advantage of improved cavity design flexibility, allowing one to make the p-side thicker using a thick n-type III-nitride TJ intracavity contact. This offers improved lateral current spreading and lower loss, compare to using ITO and p-GaN, respectively. These aspects are particularly important for achieving high-power CW VCSELs, making TJs the ideal intracavity contact for any III-nitride VCSEL. A brief overview of III-nitride TJ growth methods is also given, highlighting the molecular-beam epitaxy (MBE) technique used here. Following this overview, we compare 12 μm aperture diameter, violet emitting, TJ and ITO VCSEL experimental results, which demonstrate the significant improvement in differential efficiency and peak power resulting from the reduced loss in the TJ design. Specifically, the TJ VCSEL shows a peak power of ~550 μW with a threshold current density of ~3.5 kA/cm2, while the ITO VCSELs show peak powers of ~80 μW and threshold current densities of ~7 kA/cm2.

  2. The Hardest Superconducting Metal Nitride.

    PubMed

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

    2015-09-03

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

  3. Structure of boron nitride nanotubes

    NASA Astrophysics Data System (ADS)

    Buranova, Yu. S.; Kulnitskiy, B. A.; Perezhogin, I. A.; Blank, V. D.

    2015-01-01

    The crystallographic structure of boron nitride nanotubes has been investigated. Various defects that may arise during nanotube synthesis are revealed by electron microscopy. Nanotubes with different numbers of walls and different diameters are modeled by molecular dynamics methods. Structural features of single-wall nanotubes are demonstrated. The causes of certain defects in multiwall nanotubes are indicated.

  4. The Hardest Superconducting Metal Nitride

    DOE PAGES

    Wang, Shanmin; Antonio, Daniel; Yu, Xiaohui; ...

    2015-09-03

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

  5. Investigation into nitrided spur gears

    SciTech Connect

    Yilbas, B.S.; Coban, A.; Nickel, J.; Sunar, M.; Sami, M.; Abdul Aleem, B.J.

    1996-12-01

    The cold forging method has been widely used in industry to produce machine parts. In general, gears are produced by shaping or hobbing. One of the shaping techniques is precision forging, which has several advantages over hobbing. In the present study, cold forging of spur gears from Ti-6Al-4V material is introduced. To improve the surface properties of the resulting gears, plasma nitriding was carried out. Nuclear reaction analysis was carried out to obtain the nitrogen concentration, while the micro-PIXE technique was used to determine the elemental distribution in the matrix after forging and nitriding processes. Scanning electron microscopy and x-ray powder diffraction were used to investigate the metallurgical changes and formation of nitride components in the surface region. Microhardness and friction tests were carried out to measure the hardness depth profile and friction coefficient at the surface. Finally, scoring failure tests were conducted to determine the rotational speed at which the gears failed. Three distinct regions were obtained in the nitride region, and at the initial stages of the scoring tests, failure in surface roughness was observed in the vicinity of the tip of the gear tooth. This occurred at a particular rotational speed and work input.

  6. P-type gallium nitride

    DOEpatents

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

    1997-08-12

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

  7. Structure of boron nitride nanotubes

    SciTech Connect

    Buranova, Yu. S. Kulnitskiy, B. A.; Perezhogin, I. A.; Blank, V. D.

    2015-01-15

    The crystallographic structure of boron nitride nanotubes has been investigated. Various defects that may arise during nanotube synthesis are revealed by electron microscopy. Nanotubes with different numbers of walls and different diameters are modeled by molecular dynamics methods. Structural features of single-wall nanotubes are demonstrated. The causes of certain defects in multiwall nanotubes are indicated.

  8. The Hardest Superconducting Metal Nitride

    PubMed Central

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

    2015-01-01

    Transition–metal (TM) nitrides are a class of compounds with a wide range of properties and applications. Hard superconducting nitrides are of particular interest for electronic applications under working conditions such as coating and high stress (e.g., electromechanical systems). However, most of the known TM nitrides crystallize in the rock–salt structure, a structure that is unfavorable to resist shear strain, and they exhibit relatively low indentation hardness, typically in the range of 10–20 GPa. Here, we report high–pressure synthesis of hexagonal δ–MoN and cubic γ–MoN through an ion–exchange reaction at 3.5 GPa. The final products are in the bulk form with crystallite sizes of 50 – 80 μm. Based on indentation testing on single crystals, hexagonal δ–MoN exhibits excellent hardness of ~30 GPa, which is 30% higher than cubic γ–MoN (~23 GPa) and is so far the hardest among the known metal nitrides. The hardness enhancement in hexagonal phase is attributed to extended covalently bonded Mo–N network than that in cubic phase. The measured superconducting transition temperatures for δ–MoN and cubic γ–MoN are 13.8 and 5.5 K, respectively, in good agreement with previous measurements. PMID:26333418

  9. P-type gallium nitride

    SciTech Connect

    Rubin, Michael; Newman, Nathan; Fu, Tracy; Ross, Jennifer; Chan, James

    1997-01-01

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

  10. The Hardest Superconducting Metal Nitride

    SciTech Connect

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

    2015-09-03

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

  11. Investigation into nitrided spur gears

    NASA Astrophysics Data System (ADS)

    Yilbas, B. S.; Coban, A.; Nickel, J.; Sunar, M.; Sami, M.; Aleem, B. J. Abdul

    1996-12-01

    The cold forging method has been widely used in industry to produce machine parts. In general, gears are produced by shaping or hobbing. One of the shaping techniques is precision forging, which has several advantages over hobbing. In the present study, cold forging of spur gears from Ti-6A1-4V material is introduced. To improve the surface properties of the resulting gears, plasma nitriding was carried out. Nuclear reaction analysis was carried out to obtain the nitrogen concentration, while the micro-PIXE technique was used to determine the elemental distribution in the matrix after forging and nitriding processes. Scanning electron microscopy and x-ray powder diffraction were used to investigate the metallurgical changes and formation of nitride components in the surface region. Microhardness and friction tests were carried out to measure the hardness depth profile and friction coefficient at the surface. Finally, scoring failure tests were conducted to determine the rotational speed at which the gears failed. Three distinct regions were obtained in the nitride region, and at the initial stages of the scoring tests, failure in surface roughness was observed in the vicinity of the tip of the gear tooth. This occurred at a particular rotational speed and work input.

  12. Influence of hydrogen input partial pressure on the polarity of InN on GaAs (1 1 1)A grown by metalorganic vapor phase epitaxy

    NASA Astrophysics Data System (ADS)

    Murakami, Hisashi; Eriguchi, Ken-ichi; Torii, Jun-ichi; Cho, Hyun-Chol; Kumagai, Yoshinao; Koukitu, Akinori

    2008-04-01

    Influences of hydrogen input partial pressure in the carrier gas ( F=PHo/(PHo+PNo)) on the crystalline quality and polarities of InN on GaAs (1 1 1)A surfaces were investigated by metalorganic vapor phase epitaxy (MOVPE). It was found that the polarity of the InN was affected by the hydrogen gas in the system regardless of the polarity of GaAs starting substrate. The polarity of InN layer grown with the hydrogen partial pressure of Fo=0.004 was a mixture of In-polarity and N-polarity, while that grown with Fo=0 was In-polarity. Degradation of the crystalline quality of InN grown with Fo=0.004 occurred due to the polarity inversion during the growth. The reason why the polarity of InN was influenced by the hydrogen carrier gas could be explained by the preferential growth of N-polarity InN in the H 2 contained ambient and/or the limiting reaction of InN decomposition.

  13. Role of Inn1 and its interactions with Hof1 and Cyk3 in promoting cleavage furrow and septum formation in S. cerevisiae.

    PubMed

    Nishihama, Ryuichi; Schreiter, Jennifer H; Onishi, Masayuki; Vallen, Elizabeth A; Hanna, Julia; Moravcevic, Katarina; Lippincott, Margaret F; Han, Haesun; Lemmon, Mark A; Pringle, John R; Bi, Erfei

    2009-06-15

    Cytokinesis requires coordination of actomyosin ring (AMR) contraction with rearrangements of the plasma membrane and extracellular matrix. In Saccharomyces cerevisiae, new membrane, the chitin synthase Chs2 (which forms the primary septum [PS]), and the protein Inn1 are all delivered to the division site upon mitotic exit even when the AMR is absent. Inn1 is essential for PS formation but not for Chs2 localization. The Inn1 C-terminal region is necessary for localization, and distinct PXXP motifs in this region mediate functionally important interactions with SH3 domains in the cytokinesis proteins Hof1 (an F-BAR protein) and Cyk3 (whose overexpression can restore PS formation in inn1Delta cells). The Inn1 N terminus resembles C2 domains but does not appear to bind phospholipids; nonetheless, when overexpressed or fused to Hof1, it can provide Inn1 function even in the absence of the AMR. Thus, Inn1 and Cyk3 appear to cooperate in activating Chs2 for PS formation, which allows coordination of AMR contraction with ingression of the cleavage furrow.

  14. Phonon dispersion of indium along [111

    SciTech Connect

    Bakulin, A. S.; Overhauser, A. W.; Kaiser, H.; Werner, S. A.; Fernandez-Baca, J. A.; Smith, H. G.

    2001-02-01

    The phonon spectrum of indium along [111], measured by inelastic neutron scattering, is reported. The two shear modes at the zone-boundary point (1/2, 1/2, 1/2) are split slightly (on account of a 7.5% tetragonal distortion). They have very low frequencies, {approx}0.7 and 1.0 THz, compared to the longitudinal mode, {approx}3.4 THz. These measurements verify the theoretical dispersion predicted by the dynamic pseudopotential theory of phonons for free-electron-like metals.

  15. Rapid solidification of indium: Modeling subcooling

    SciTech Connect

    Le Bot, C. Delaunay, D.

    2008-05-15

    This paper deals with the study of crystallization kinetics. A pure metal - indium - is subjected to different cooling rates by analyzing phenomena with a differential scanning calorimeter. Thanks to the thermal flux obtained by this device and to the temperature determined with a thermocouple inside the metal sample, and according to the modified Avrami theory, the aim was to determine a temperature dependent function K which links thermodynamic properties to a macroscopic model of crystallization kinetics. Experiments highlight the recalescence phenomenon and show that this function has a shape similar to that of the nucleation rate.

  16. Fabrication, structure and mechanical properties of indium nanopillars

    SciTech Connect

    Lee, Gyuhyon; Kim, Ju-Young; Budiman, Arief Suriadi; Tamura, Nobumichi; Kunz, Martin; Chen, Kai; Burek, Michael J.; Greer, Julia R.; Tsui, Ting Y.

    2010-01-01

    Solid and hollow cylindrical indium pillars with nanoscale diameters were prepared using electron beam lithography followed by the electroplating fabrication method. The microstructure of the solid-core indium pillars was characterized by scanning micro-X-ray diffraction, which shows that the indium pillars were annealed at room temperature with very few dislocations remaining in the samples. The mechanical properties of the solid pillars were characterized using a uniaxial microcompression technique, which demonstrated that the engineering yield stress is {approx}9 times greater than bulk and is {approx}1/28 of the indium shear modulus, suggesting that the attained stresses are close to theoretical strength. Microcompression of hollow indium nanopillars showed evidence of brittle fracture. This may suggest that the failure mode for one of the most ductile metals can become brittle when the feature size is sufficiently small.

  17. Subclinical interstitial lung damage in workers exposed to indium compounds

    PubMed Central

    2013-01-01

    Objectives The present study was designed to determine whether there is a relationship between indium compound exposure and interstitial lung damage in workers employed at indium tin oxide manufacturing and reclaiming factories in Korea. Methods In 2012, we conducted a study for the prevention of indium induced lung damage in Korea and identified 78 workers who had serum indium or Krebs von den Lungen-6 (KL-6) levels that were higher than the reference values set in Japan (3 μg/L and 500 U/mL, respectively). Thirty-four of the 78 workers underwent chest high-resolution computed tomography (HRCT), and their data were used for statistical analysis. Results Geometric means (geometric standard deviations) for serum indium, KL-6, and surfactant protein D (SP-D) were 10.9 (6.65) μg/L, 859.0 (1.85) U/mL, and 179.27 (1.81) ng/mL, respectively. HRCT showed intralobular interstitial thickening in 9 workers. A dose–response trend was statistically significant for blood KL-6 levels. All workers who had indium levels ≥50 μg/L had KL-6 levels that exceeded the reference values. However, dose–response trends for blood SP-D levels, KL-6 levels, SP-D levels, and interstitial changes on the HRCT scans were not significantly different. Conclusions Our findings suggest that interstitial lung changes could be present in workers with indium exposure. Further studies are required and health risk information regarding indium exposure should be communicated to workers and employers in industries where indium compounds are used to prevent indium induced lung damage in Korea. PMID:24472147

  18. Fluxless indium and silver-indium bonding processes for photonics and high-temperature electronics

    NASA Astrophysics Data System (ADS)

    So, William Wilson

    A fluxless oxidation-free bonding technology using multilayer composite solders based on indium, or low melting temperature indium. alloys such as Ag-In, In-Sn and Au-In has been developed and studied. This technology eliminates the need of flux and scrubbing motion that are used in conventional soldering processes, and still produces good quality joints. By depositing multilayer composite materials in high vacuum, we eliminate the formation of an oxide layer thus removing the origin of the problem---solder oxidation. To understand the oxidation kinetics in the bonding process, I have modeled the oxidation rate of tin, which follows a parabolic growth law. For completeness of the oxidation model, I incorporated the temperature dependency of Henry's coefficient in the oxidation model. To prevent the solder material from oxidation when exposing to atmosphere, I have developed a technique, which utilizes the in-situ formation of stable intermetallic compound on the outer surface, or a gold layer to protect the bonding materials. The bonding is achieved by means of solid-liquid interdiffusion (SLID) and in-situ compound formation. The first alloy system that I studied is indium-silver. GaAs and silicon dice have been successfully bonded on silicon or glass substrates. The bonding quality is examined by a Scanning Acoustic Microscope (SAM). The results confirm that void-free joints are achieved. Cross-sections of the joint are examined using a Scanning Electron Microscope (SEM) equipped with Energy Dispersive X-ray (EDX) spectroscopy. The results reveal that the joint is composed of AuIn2, AgIn2-intermetallic compound and pure indium. From the Ag-In phase diagram, as indium composition is reduced to 25 wt. %, the solidus temperature jumps from 144 to above 695°C. By modifying the design of the multilayer composite, we developed a 210°C process to produce 700°C joints. All the well-bonded devices, before or after annealing, exceed the shear test force requirement of 2

  19. Highly ordered horizontal indium gallium arsenide/indium phosphide multi-quantum-well in wire structure on (001) silicon substrates

    NASA Astrophysics Data System (ADS)

    Han, Yu; Li, Qiang; Lau, Kei May

    2016-12-01

    We report the characteristics of indium gallium arsenide stacked quantum structures inside planar indium phosphide nanowires grown on exact (001) silicon substrates. The morphological evolution of the indium phosphide ridge buffers inside sub-micron trenches has been studied, and the role of inter-facet diffusion in this process is discussed. Inside a single indium phosphide nanowire, we are able to stack quantum structures including indium gallium arsenide flat quantum wells, quasi-quantum wires, quantum wires, and ridge quantum wells. Room temperature photoluminescence measurements reveal a broadband emission spectrum centered at 1550 nm. Power dependent photoluminescence analysis indicates the presence of quasi-continuum states. This work thus provides insights into the design and growth process control of multiple quantum wells in wire structures for high performance nanowire lasers on a silicon substrate with 1550 nm band emission.

  20. Indium antimonide large-format detector arrays

    NASA Astrophysics Data System (ADS)

    Davis, Mike; Greiner, Mark

    2011-06-01

    Large format infrared imaging sensors are required to achieve simultaneously high resolution and wide field of view image data. Infrared sensors are generally required to be cooled from room temperature to cryogenic temperatures in less than 10 min thousands of times during their lifetime. The challenge is to remove mechanical stress, which is due to different materials with different coefficients of expansion, over a very wide temperature range and at the same time, provide a high sensitivity and high resolution image data. These challenges are met by developing a hybrid where the indium antimonide detector elements (pixels) are unconnected islands that essentially float on a silicon substrate and form a near perfect match to the silicon read-out circuit. Since the pixels are unconnected and isolated from each other, the array is reticulated. This paper shows that the front side illuminated and reticulated element indium antimonide focal plane developed at L-3 Cincinnati Electronics are robust, approach background limited sensitivity limit, and provide the resolution expected of the reticulated pixel array.

  1. Patterning of Indium Tin Oxide Films

    NASA Technical Reports Server (NTRS)

    Immer, Christopher

    2008-01-01

    A relatively rapid, economical process has been devised for patterning a thin film of indium tin oxide (ITO) that has been deposited on a polyester film. ITO is a transparent, electrically conductive substance made from a mixture of indium oxide and tin oxide that is commonly used in touch panels, liquid-crystal and plasma display devices, gas sensors, and solar photovoltaic panels. In a typical application, the ITO film must be patterned to form electrodes, current collectors, and the like. Heretofore it has been common practice to pattern an ITO film by means of either a laser ablation process or a photolithography/etching process. The laser ablation process includes the use of expensive equipment to precisely position and focus a laser. The photolithography/etching process is time-consuming. The present process is a variant of the direct toner process an inexpensive but often highly effective process for patterning conductors for printed circuits. Relative to a conventional photolithography/ etching process, this process is simpler, takes less time, and is less expensive. This process involves equipment that costs less than $500 (at 2005 prices) and enables patterning of an ITO film in a process time of less than about a half hour.

  2. Longitudinal Splitting of Boron Nitride Nanotubes for the Facile Synthesis of High Quality Boron Nitride Nanoribbons

    DTIC Science & Technology

    2011-05-24

    Boron Nitride Nanotubes for the Facile Synthesis of High Quality Boron Nitride Nanoribbons Kris J. Erickson,†,‡,§ Ashley...We report the synthesis of BNNRs through the potassium-intercalation-induced longitudinal splitting of boron nitride nanotubes (BNNTs). This facile...COVERED 00-00-2011 to 00-00-2011 4. TITLE AND SUBTITLE Longitudinal Splitting of Boron Nitride Nanotubes for the Facile Synthesis of High

  3. A reduction nitridation route to boron nitride nanotubes

    NASA Astrophysics Data System (ADS)

    Chen, X.; Wang, X.; Liu, J.; Wang, Z.; Qian, Y.

    2005-10-01

    Multiwalled boron nitride nanotubes were synthesized through a simple reduction nitridation route, in which boron trifluoride etherate ((C2H5)2OBF3) and sodium azide (NaN3) were used as reactants in the presence of Fe-Ni powder at 600 °C for 12 h. The obtained BN nanotubes have an average outer diameter of 60 nm, an average inner diameter of 30 nm, and an average length up to 300 nm. Some nanobamboo structured BN were found coexisting with the BN nanotubes. The experimental results show that the reaction temperature and Fe-Ni powder play important roles in the formation of BN nanotubes. Finally, a possible formation mechanism is also discussed.

  4. Electrical and optical properties of InN with periodic metallic in insertions

    SciTech Connect

    Komissarova, T. A. Shubina, T. V.; Jmerik, V. N.; Ivanov, S. V.; Ryabova, L. I.; Khokhlov, D. R.; Vasson, A.; Leymarie, J.; Araki, T.; Nanishi, Y.

    2009-03-15

    We report on a growth by molecular beam epitaxy of InN:In semiconductor/metal composite structures containing periodically inserted arrays of In clusters formed by intentional deposition of In metal films in a thickness range of 2-48 monolayers. It was found that indium insertions do not change markedly carrier mobility in the composites, that remains in the 1300-1600 cm{sup 2}/(V s) range, while carrier concentration increases with rising In amount. Spectra of thermally detected optical absorption do not exhibit a noticeable Burstein-Moss shift of a principal absorption edge with increasing the carrier concentration, but rather complicated modification of their shapes.

  5. Aluminum Nitride Nanofibers fabricated using Electrospinning and Nitridation

    NASA Astrophysics Data System (ADS)

    Barbosa, Xenia; Campo, Eva; Santiago, Jorge; Ramos, Idalia

    2012-02-01

    Aluminum Nitride (AlN) and other nitride semiconductors are important materials in the fields of optoelectronics and electronics. AlN nanofibers were synthesized using electrospinning and subsequent heating under N2 and NH3 atmospheres. The precursor solution for electrospining contains aluminium nitrate and cellulose acetate. The electrospun nanofibers were heated in N2 to eliminate the polymer and produce Al2O3, and then nitridized at a temperature of 1200 C under NH3 flow. Scanning Electron Microscopy (SEM) observations demonstrate the production of fibers with diameters ranging from a few nanometers to several micrometers. X-Ray Diffraction and UV-VIs analyses show the production of AlN nanofibers with hexagonal wurzite structure and a band gap of approximately approximately 6 eV. Current-Voltage measurements on a single AlN fiber with gold electrodes suggest the formation of a Schottky contact The fabrication method and results from the fibers characterization will be presented.

  6. III-nitride core–shell nanowire arrayed solar cells.

    PubMed

    Wierer, Jonathan J; Li, Qiming; Koleske, Daniel D; Lee, Stephen R; Wang, George T

    2012-05-17

    A solar cell based on a hybrid nanowire–film architecture consisting of a vertically aligned array of InGaN/GaN multi-quantum well core–shell nanowires which are electrically connected by a coalesced p-InGaN canopy layer is demonstrated. This unique hybrid structure allows for standard planar device processing, solving a key challenge with nanowire device integration, while enabling various advantages by the nanowire absorbing region such as higher indium composition InGaN layers by elastic strain relief, more efficient carrier collection in thinner layers, and enhanced light trapping from nano-scale optical index changes. This hybrid structure is fabricated into working solar cells exhibiting photoresponse out to 2.1 eV and short-circuit current densities of ~1 mA cm(-2) under 1 sun AM1.5G. This proof-of-concept nanowire-based device demonstrates a route forward for high-efficiency III-nitride solar cells.

  7. Analysis of plasma-nitrided steels

    NASA Technical Reports Server (NTRS)

    Salik, J.; Ferrante, J.; Honecy, F.; Hoffman, R., Jr.

    1986-01-01

    The analysis of plasma nitrided steels can be divided to two main categories - structural and chemical. Structural analysis can provide information not only on the hardening mechanisms but also on the fundamental processes involved. Chemical analysis can be used to study the kinetics for the nitriding process and its mechanisms. In this paper preliminary results obtained by several techniques of both categories are presented and the applicability of those techniques to the analysis of plasma-nitrided steels is discussed.

  8. Synthesis, Properties, and Applications Of Boron Nitride

    NASA Technical Reports Server (NTRS)

    Pouch, John J.; Alterovitz, Samuel A.

    1993-01-01

    Report describes synthesis, properties, and applications of boron nitride. Especially in thin-film form. Boron nitride films useful as masks in x-ray lithography; as layers for passivation of high-speed microelectronic circuits; insulating films; hard, wear-resistant, protective films for optical components; lubricants; and radiation detectors. Present status of single-crystal growth of boron nitride indicates promising candidate for use in high-temperature semiconductor electronics.

  9. Synthesis, Properties, and Applications Of Boron Nitride

    NASA Technical Reports Server (NTRS)

    Pouch, John J.; Alterovitz, Samuel A.

    1993-01-01

    Report describes synthesis, properties, and applications of boron nitride. Especially in thin-film form. Boron nitride films useful as masks in x-ray lithography; as layers for passivation of high-speed microelectronic circuits; insulating films; hard, wear-resistant, protective films for optical components; lubricants; and radiation detectors. Present status of single-crystal growth of boron nitride indicates promising candidate for use in high-temperature semiconductor electronics.

  10. Deep-UV plasmonics of indium (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Kumamoto, Yasuaki; Saito, Yuika; Taguchi, Atsushi; Honda, Mitsuhiro; Kawata, Satoshi

    2016-09-01

    Deep-UV (DUV) plasmonics can expand the possibilities of DUV-based techniques (i.e. UV lithography, UV spectroscopy, UV imaging, UV disinfection). Here we present that indium is useful for research of DUV plasmonics. According to dielectric function, indium and aluminum are low-loss, DUV plasmonic metals, of which the imaginary parts are far smaller than those of other metals (i.e. rhodium, platinum) in the DUV range. Additionally, the real parts in the whole DUV range are close to but smaller than -2, allowing efficient generation of surface plasmon polaritons on an indium or aluminum nanosphere. In comparison to aluminum, indium provides a distinctive feature for fabricating DUV-resonant substrates. It is highly apt to form a grainy deposition film on a standard, optically transparent substrate (i.e. fused silica). The surface plasmon resonance wavelength becomes promptly tailored by simply varying the deposition thickness of the films, resulting in different grain sizes. Thus, we fabricated indium-coated substrates having different plasmon resonance wavelengths by varying the deposition thicknesses from 10 to 50 nm. DUV resonance Raman scattering of adenine molecules was best enhanced using the 25 nm deposition thickness substrates by the factor of 2. Furthermore, the FDTD calculation simulated the electromagnetic field enhancement over a grainy, indium-coated fused silica substrate. Both results indicate how indium plays an indispensable role in study of DUV plasmonics.

  11. Factors Affecting the Toxicity of the Element Indium

    PubMed Central

    Castronovo, F. P.; Wagner, H. N.

    1971-01-01

    Hydrated indium oxide is 40 times more toxic than ionic indium, when expressed as lethality per quantity of metal injected. Ionic indium is nephrotoxic, causing damage in the proximal portion of the proximal convoluted tubule. In this respect, it resembles the element mercury. At extremely high doses, ionic indium causes focal necrosis in the liver. Hydrated indium oxide causes damage to those organs which contain phagocytic cells which clear the insoluble particles from the blood after i.v. injection. Actual focal necrosis was found in the liver, spleen and bone marrow. Damage was also found in the thymus and lymph nodes. At extremely high doses, damage was observed in the proximal convoluted tubules of the kidney. Hydrated indium oxide caused extensive haemorrhage and marked thrombocytopenia. Fibrin thrombi were observed in the liver. The increase in toxicity of indium resulting from phagocytosis of insoluble oxides by the reticuloendothelial system may represent a general mechanism by which the toxicity of certain heavy metals is increased. ImagesFigs. 7-9Figs. 3-6Fig. 2 PMID:5125268

  12. Synthesis of indium nanoparticles: digestive ripening under mild conditions.

    PubMed

    Cingarapu, Sreeram; Yang, Zhiqiang; Sorensen, Christopher M; Klabunde, Kenneth J

    2011-06-06

    Here we report the synthesis of monodispersed indium nanoparticles by evaporation/condensation of indium shot using the solvated metal atom dispersion (SMAD) technique, followed by digestive ripening in low boiling point (BP 38 °C) methylene chloride and in a high boiling point (BP 110 °C) toluene solvent. The as-prepared SMAD indium nanoparticles are polydispersed with particle size ranging from 25 to 50 nm, but upon digestive ripening (heating of colloidal material at the boiling point of solvent in presence of excess surface active ligands) in methylene chloride, a remarkable reduction of particle size was achieved. In higher boiling solvent (toluene), where the indium nanoparticles at reflux temperature are probably melted, it does not allow the best result, and less monodispersity is achieved. We employed different surface active ligands (amine, phosphine, and mixed ligands) to passivate these indium nanoparticles. The temporal evolution of the surface plasmon of indium nanoparticles was monitored by in situ UV-vis spectroscopy, and particles were characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The merits of this synthesis procedure are the use of bulk indium as starting material, tuning the particle size in low boiling point solvent, particle size adjustment with the choice of ligand, and a possible scale up. © 2011 American Chemical Society

  13. Topotactic synthesis of vanadium nitride solid foams

    SciTech Connect

    Oyama, S.T.; Kapoor, R.; Oyama, H.T.; Hofmann, D.J.; Matijevic, E. )

    1993-06-01

    Vanadium nitride has been synthesized with a surface area of 120 m[sup 2] g[sup [minus]1] by temperature programmed nitridation of a foam-like vanadium oxide (35 m[sup 2] g[sup [minus]1]), precipitated from vanadate solutions. The nitridation reaction was established to be topotactic and pseudomorphous by x-ray powder diffraction and scanning electron microscopy. The crystallographic relationship between the nitride and oxide was [l brace]200[r brace]//[l brace]001[r brace]. The effect of precursor geometry on the product size and shape was investigated by employing vanadium oxide solids of different morphologies.

  14. High-efficiency indium tin oxide/indium phosphide solar cells

    NASA Technical Reports Server (NTRS)

    Li, X.; Wanlass, M. W.; Gessert, T. A.; Emery, K. A.; Coutts, T. J.

    1989-01-01

    Improvements in the performance of indium tin oxide (ITO)/indium phosphide solar cells have been realized by the dc magnetron sputter deposition of n-ITO onto an epitaxial p/p(+) structure grown on commercial p(+) bulk substrates. The highest efficiency cells were achieved when the surface of the epilayer was exposed to an Ar/H2 plasma before depositing the bulk of the ITO in a more typical Ar/O2 plasma. With H2 processing, global efficiencies of 18.9 percent were achieved. It is suggested that the excellent performance of these solar cells results from the optimization of the doping, thickness, transport, and surface properties of the p-type base, as well as from better control over the ITO deposition procedure.

  15. High-efficiency indium tin oxide/indium phosphide solar cells

    NASA Technical Reports Server (NTRS)

    Li, X.; Wanlass, M. W.; Gessert, T. A.; Emery, K. A.; Coutts, T. J.

    1989-01-01

    Improvements in the performance of indium tin oxide (ITO)/indium phosphide solar cells have been realized by the dc magnetron sputter deposition of n-ITO onto an epitaxial p/p(+) structure grown on commercial p(+) bulk substrates. The highest efficiency cells were achieved when the surface of the epilayer was exposed to an Ar/H2 plasma before depositing the bulk of the ITO in a more typical Ar/O2 plasma. With H2 processing, global efficiencies of 18.9 percent were achieved. It is suggested that the excellent performance of these solar cells results from the optimization of the doping, thickness, transport, and surface properties of the p-type base, as well as from better control over the ITO deposition procedure.

  16. Manufacture of sintered silicon nitrides

    NASA Technical Reports Server (NTRS)

    Iwai, T.

    1985-01-01

    Sintered silicon nitrides are manufactured by sintering Si3N powder containing 2 to 15% in wt of a powder mixture composed of nitride powder of lanthanide or Y 100 parts and AIN powder less than 100 parts at 1500 to 1900 deg. temperature under a pressure of less than 200 Kg/sq. cm. The sintered Si3N has high mechanical strength in high temperature. Thus, Si3N4 93.0, Y 5.0 and AlN 2.0% in weight were wet mixed in acetone in N atom, molded and sintered at 1750 deg. and 1000 Kg/sq. cm. to give a sintered body having high hardness.

  17. Structural properties of InN films grown on O-face ZnO(0001) by plasma-assisted molecular beam epitaxy

    SciTech Connect

    Cho, Yong Jin; Brandt, Oliver; Kaganer, Vladimir M.; Ramsteiner, Manfred; Riechert, Henning; Korytov, Maxim; Albrecht, Martin

    2012-04-09

    We study the impact of substrate temperature and layer thickness on the morphological and structural properties of InN films directly grown on O-face ZnO(0001) substrates by plasma-assisted molecular beam epitaxy. With increasing substrate temperature, an interfacial reaction between InN and ZnO takes place that eventually results in the formation of cubic In{sub 2}O{sub 3} and voids. The properties of the InN films, however, are found to be unaffected by this reaction for substrate temperatures less than 550 deg. C. In fact, both the morphological and the structural quality of InN improve with increasing substrate temperature in the range from 350 to 500 deg. C. High quality films with low threading dislocation densities are demonstrated.

  18. Dislocation reduction via selective-area growth of InN accompanied by lateral growth by rf-plasma-assisted molecular-beam epitaxy

    SciTech Connect

    Kamimura, Jumpei; Kishino, Katsumi; Kikuchi, Akihiko

    2010-10-04

    We investigated the selective-area growth (SAG) of InN by rf-plasma-assisted molecular-beam epitaxy using molybdenum (Mo)-mask-patterned sapphire (0001) substrates, which resulted in the formation of regularly arranged N-polar InN microcrystals. Transmission electron microscopy observation confirmed that the laterally grown side areas were nearly dislocation-free, although many threading dislocations (10{sup 9}-10{sup 10} cm{sup -2}) were generated at the InN/sapphire interface and propagated into the center of the InN microcrystals along the crystal c-axis. The laterally grown InN microcrystals exhibited narrow near-IR emission spectra with a peak photon energy of 0.627 eV and a linewidth of 39 meV at room temperature.

  19. Dynamic atomic layer epitaxy of InN on/in +c-GaN matrix: Effect of “In+N” coverage and capping timing by GaN layer on effective InN thickness

    SciTech Connect

    Yoshikawa, Akihiko; Kusakabe, Kazuhide; Hashimoto, Naoki; Hwang, Eun-Sook; Itoi, Takaomi

    2016-01-11

    The growth front in the self-organizing and self-limiting epitaxy of ∼1 monolayer (ML)-thick InN wells on/in +c-GaN matrix by molecular beam epitaxy (MBE) has been studied in detail, with special attention given to the behavior and role of the N atoms. The growth temperatures of interest are above 600 °C, far higher than the typical upper critical temperature of 500 °C in MBE. It was confirmed that 2 ML-thick InN wells can be frozen/inserted in GaN matrix at 620 °C, but it was found that N atoms at the growth front tend to selectively re-evaporate more quickly than In atoms at temperatures higher than 650 °C. As a result, the effective thickness of inserted InN wells in the GaN matrix at 660–670 °C were basically 1 ML or sub-ML, even though they were capped by a GaN barrier at the time of 2 ML “In+N” coverage. Furthermore, it was found that the N atoms located below In atoms in the dynamic atomic layer epitaxy growth front had remarkably weaker bonding to the +c-GaN surface.

  20. Carbothermal synthesis of aluminum nitride

    SciTech Connect

    Silverman, L.D. )

    1988-07-01

    A synthetic route is described for making carbothermally reduced powders from colloidal oxide precursors trapped in a polymer matrix. The entrapping resin, which is formed by polymerization of a monomer dissolved in the colloid, serves both to minimize particle agglomeration during reaction and as the source of carbon for reduction. Following reduction, the remaining carbon matrix is removed by oxidation. This strategy was used to synthesize aluminum nitride powder via trapping of colloidal alumina in poly(furfuryl alcohol) resin.

  1. On the origin of photoluminescence in indium oxide octahedron structures

    SciTech Connect

    Kumar, Mukesh; Singh, V. N.; Mehta, B. R.; Singh, J. P.; Singh, F.; Lakshmi, K. V.

    2008-04-28

    A sixfold decrease in photoluminescence signal intensity at 590 nm with increase in deposition time from 3 to 12 h has been observed in single crystalline indium oxide octahedron structures grown by vapor-phase evaporation method. Electron paramagnetic resonance and energy dispersive x-ray analysis confirm that the concentration of oxygen vacancies increases with deposition time. These results are contrary to the previous reports where oxygen vacancies were shown to be responsible for photoluminescence in indium oxide structures. Our results indicate that indium interstitials and their associated complex defects other than oxygen vacancies are responsible for the photoluminescence in In{sub 2}O{sub 3} microstructures.

  2. Reflectance of metallic indium for solar energy applications

    NASA Technical Reports Server (NTRS)

    Bouquet, F. L.; Hasegawa, T.

    1984-01-01

    An investigation has been conducted in order to compile quantitative data on the reflective properties of metallic indium. The fabricated samples were of sufficiently high quality that differences from similar second-surface silvered mirrors were not apparent to the human eye. Three second-surface mirror samples were prepared by means of vacuum deposition techniques, yielding indium thicknesses of approximately 1000 A. Both hemispherical and specular measurements were made. It is concluded that metallic indium possesses a sufficiently high specular reflectance to be potentially useful in many solar energy applications.

  3. Reflectance of metallic indium for solar energy applications

    NASA Technical Reports Server (NTRS)

    Bouquet, F. L.; Hasegawa, T.

    1984-01-01

    An investigation has been conducted in order to compile quantitative data on the reflective properties of metallic indium. The fabricated samples were of sufficiently high quality that differences from similar second-surface silvered mirrors were not apparent to the human eye. Three second-surface mirror samples were prepared by means of vacuum deposition techniques, yielding indium thicknesses of approximately 1000 A. Both hemispherical and specular measurements were made. It is concluded that metallic indium possesses a sufficiently high specular reflectance to be potentially useful in many solar energy applications.

  4. Kinetic investigation of indium-palladium alloy electrodeposition

    SciTech Connect

    Vinogradov, S.N.; Perelygin, Yu.P.; Efimov, E.A.

    1988-01-01

    The kinetics of alloy deposition of ammonium-citrate electrolyte used to produce alloys with indium content were studied. The electrolytes were composed of palladium, indium, ammonium sulfate, monosodium citrate, ammonium chloride, and saccharin at pH 9.5. Stationary and rotating disk electrodes and a potentiostat were used for the investigation. Spectrophotometry determined the mixed formation of citrate-ammonia palladium complexes. It was found that the considerable depolarization of indium ion discharge into the alloy occurred when saccharin was present in the electrolyte, and its direct electroreduction occurs from hydroxide compounds.

  5. Determination of indium in rocks by substoichiometric radioisotope dilution analysis

    USGS Publications Warehouse

    Greenland, L. Paul; Campbell, E.Y.

    1973-01-01

    Rocks containing 10-140 ng of indium per g are decomposed with hydrofluoric and nitric acids in the presence of 114In. Indium is separated from other constituents by sequential extractions of the bromide, cupferronate, and acetylacetonate, and is then reacted with a substoichiometric amont of EDTA. Excess of indium is removed by acetylacetone extraction and the specific activity of the complexed fraction is determined by counting 114In. Analyses of the U.S.G.S. standard rocks are reported. These show good agreement with previous neutron activation analyses. Repetitive rock analyses indicated an analytical precision of ??4-7%. ?? 1973.

  6. Time-integrated photoluminescence and pump-probe reflection spectroscopy of Si doped InN thin films

    SciTech Connect

    Mohanta, Antaryami; Jang, Der-Jun Wang, Ming-Sung; Tu, L. W.

    2014-01-28

    Temperature and excitation power dependent time-integrated photoluminescence of Si doped InN thin films are investigated. Photoluminescence (PL) spectra at low temperatures are described by single emission peak ensued due to “free-to-bound” recombination; whereas PL spectra at higher temperatures above 150 K are characterized by both “band-to-band” and “free-to-bound” transition. Carrier dynamics of Si doped InN thin films is studied using pump-probe reflection spectroscopy at room temperature. The hot electron cooling process is well described by electron-electron scattering. The dependence of the hot electron cooling rate on total electron density shows sublinear to linear behavior with increase of background electron density. The variation of the carrier recombination lifetime with total electron density implicates the dominance of the defect-related nonradiative recombination channel over other recombination processes.

  7. Role of native defects in nitrogen flux dependent carrier concentration of InN films grown by molecular beam epitaxy

    SciTech Connect

    Tangi, Malleswararao; Kuyyalil, Jithesh; Shivaprasad, S. M.

    2012-10-01

    We address the carrier concentration, strain, and bandgap issue of InN films grown on c-sapphire at different N-flux by molecular beam epitaxy using x-ray diffraction and x-ray photoelectron spectroscopy. We demonstrate that the strain in InN films arises due to point defects like nitrogen interstitials and nitrogen antisites. We report minimal biaxial strain due to relaxed growth morphology and a minimal hydrostatic strain arising due to interstitial nitrogen atoms being partially compensated by nitrogen antisites. We find that the variation in absorption edge can be attributed to defect induced carrier concentration and that nitrogen interstitials and nitrogen antisites act as donors that yield the respective absorption edge and Moss-Burstein shift. Our studies are a step towards the ability to form low carrier concentration strain-relaxed films and to determine the intrinsic band gap value for this technologically important material.

  8. Surface structure and surface kinetics of InN grown by plasma-assisted atomic layer epitaxy: A HREELS study

    SciTech Connect

    Acharya, Ananta R. E-mail: anantaach@gmail.com; Thoms, Brian D.; Nepal, Neeraj; Eddy, Charles R.

    2015-03-15

    The surface bonding configuration and kinetics of hydrogen desorption from InN grown by plasma-assisted atomic layer epitaxy have been investigated. High resolution electron energy loss spectra exhibited loss peaks assigned to a Fuchs–Kliewer surface phonon, N-N and N-H surface species. The surface N-N vibrations are attributed to surface defects. The observation of N-H but no In-H surface species suggested N-terminated InN. Isothermal desorption data were best fit by the first-order desorption kinetics with an activation energy of (0.88 ± 0.06) eV and pre-exponential factor of (1.5 ± 0.5) × 10{sup 5 }s{sup −1}.

  9. Polarity control and transport properties of Mg-doped (0001) InN by plasma-assisted molecular beam epitaxy

    SciTech Connect

    Choi, Soojeong; Wu Feng; Bierwagen, Oliver; Speck, James S.

    2013-05-15

    The authors report on the plasma-assisted molecular beam epitaxy growth and carrier transport of Mg-doped In-face (0001) InN. The 1.2 {mu}m thick InN films were grown on GaN:Fe templates under metal rich conditions with Mg concentration from 1 Multiplication-Sign 10{sup 17}/cm{sup 3} to 3 Multiplication-Sign 10{sup 20}/cm{sup 3}. A morphological transition, associated with the formation of V-shape polarity inversion domains, was observed at Mg concentration over 7 Multiplication-Sign 10{sup 19}/cm{sup 3} by atomic force microscopy and transmission electron microscopy. Seebeck measurements indicated p-type conductivity for Mg-concentrations from 9 Multiplication-Sign 10{sup 17}/cm{sup 3} to 7 Multiplication-Sign 10{sup 19}/cm{sup 3}, i.e., as it exceeded the compensating (unintentional) donor concentration.

  10. Silicon nitride equation of state

    NASA Astrophysics Data System (ADS)

    Brown, Robert C.; Swaminathan, Pazhayannur K.

    2017-01-01

    This report presents the development of a global, multi-phase equation of state (EOS) for the ceramic silicon nitride (Si3N4).1 Structural forms include amorphous silicon nitride normally used as a thin film and three crystalline polymorphs. Crystalline phases include hexagonal α-Si3N4, hexagonal β-Si3N4, and the cubic spinel c-Si3N4. Decomposition at about 1900 °C results in a liquid silicon phase and gas phase products such as molecular nitrogen, atomic nitrogen, and atomic silicon. The silicon nitride EOS was developed using EOSPro which is a new and extended version of the PANDA II code. Both codes are valuable tools and have been used successfully for a variety of material classes. Both PANDA II and EOSPro can generate a tabular EOS that can be used in conjunction with hydrocodes. The paper describes the development efforts for the component solid phases and presents results obtained using the EOSPro phase transition model to investigate the solid-solid phase transitions in relation to the available shock data that have indicated a complex and slow time dependent phase change to the c-Si3N4 phase. Furthermore, the EOSPro mixture model is used to develop a model for the decomposition products; however, the need for a kinetic approach is suggested to combine with the single component solid models to simulate and further investigate the global phase coexistences.

  11. Silicon Nitride Equation of State

    NASA Astrophysics Data System (ADS)

    Swaminathan, Pazhayannur; Brown, Robert

    2015-06-01

    This report presents the development a global, multi-phase equation of state (EOS) for the ceramic silicon nitride (Si3N4) . Structural forms include amorphous silicon nitride normally used as a thin film and three crystalline polymorphs. Crystalline phases include hexagonal α-Si3N4, hexagonalβ-Si3N4, and the cubic spinel c-Si3N4. Decomposition at about 1900 °C results in a liquid silicon phase and gas phase products such as molecular nitrogen, atomic nitrogen, and atomic silicon. The silicon nitride EOS was developed using EOSPro which is a new and extended version of the PANDA II code. Both codes are valuable tools and have been used successfully for a variety of material classes. Both PANDA II and EOSPro can generate a tabular EOS that can be used in conjunction with hydrocodes. The paper describes the development efforts for the component solid phases and presents results obtained using the EOSPro phase transition model to investigate the solid-solid phase transitions in relation to the available shock data. Furthermore, the EOSPro mixture model is used to develop a model for the decomposition products and then combined with the single component solid models to study the global phase diagram. Sponsored by the NASA Goddard Space Flight Center Living With a Star program office.

  12. Tissue distribution of indium after repeated intratracheal instillations of indium-tin oxide into the lungs of hamsters.

    PubMed

    Tanaka, Akiyo; Hirata, Miyuki; Matsumura, Nagisa; Kiyohara, Yutaka

    2015-01-01

    The aim of this study was to analyze the tissue distribution of indium after intratracheally instilling indium-tin oxide (ITO) into the lungs of hamsters. Male Syrian hamsters received an intratracheal dose of 3 mg/kg or 6 mg/kg of ITO particles containing 2.2 mg/kg or 4.5 mg/kg of indium, twice weekly for 8 weeks. In parallel, control hamsters received only an intratracheal dose of distilled water. A subset of hamsters was euthanized periodically throughout the study from 8 up to 78 weeks after the final instillation. The distribution of indium in the lungs, liver, kidneys and spleen, as well as pathological changes in the liver, kidneys, and spleen, was determined. The contents of indium in the lungs in the two ITO groups gradually decreased over the 78-week observation period, with elimination half-lives of approximately 142 weeks for the 3 mg/kg ITO group and 124 weeks for the 6 mg/kg ITO. The indium concentrations in the liver, kidneys, and spleen gradually increased throughout the observation period. Although foci of the lesions were observed histopathologically in the extrapulmonary organs among the two ITO groups, the control group showed similar lesions. The results clearly demonstrate that the clearance of indium from the body is extremely slow after intratracheal instillation in hamsters.

  13. Demonstration of a III-nitride vertical-cavity surface-emitting laser with a III-nitride tunnel junction intracavity contact

    NASA Astrophysics Data System (ADS)

    Leonard, J. T.; Young, E. C.; Yonkee, B. P.; Cohen, D. A.; Margalith, T.; DenBaars, S. P.; Speck, J. S.; Nakamura, S.

    2015-08-01

    We report on a III-nitride vertical-cavity surface-emitting laser (VCSEL) with a III-nitride tunnel junction (TJ) intracavity contact. The violet nonpolar VCSEL employing the TJ is compared to an equivalent VCSEL with a tin-doped indium oxide (ITO) intracavity contact. The TJ VCSEL shows a threshold current density (Jth) of ˜3.5 kA/cm2, compared to the ITO VCSEL Jth of 8 kA/cm2. The differential efficiency of the TJ VCSEL is also observed to be significantly higher than that of the ITO VCSEL, reaching a peak power of ˜550 μW, compared to ˜80 μW for the ITO VCSEL. Both VCSELs display filamentary lasing in the current aperture, which we believe to be predominantly a result of local variations in contact resistance, which may induce local variations in refractive index and free carrier absorption. Beyond the analyses of the lasing characteristics, we discuss the molecular-beam epitaxy (MBE) regrowth of the TJ, as well as its unexpected performance based on band-diagram simulations. Furthermore, we investigate the intrinsic advantages of using a TJ intracavity contact in a VCSEL using a 1D mode profile analysis to approximate the threshold modal gain and general loss contributions in the TJ and ITO VCSEL.

  14. Demonstration of a III-nitride vertical-cavity surface-emitting laser with a III-nitride tunnel junction intracavity contact

    SciTech Connect

    Leonard, J. T. Young, E. C.; Yonkee, B. P.; Cohen, D. A.; Margalith, T.; Speck, J. S.; DenBaars, S. P.; Nakamura, S.

    2015-08-31

    We report on a III-nitride vertical-cavity surface-emitting laser (VCSEL) with a III-nitride tunnel junction (TJ) intracavity contact. The violet nonpolar VCSEL employing the TJ is compared to an equivalent VCSEL with a tin-doped indium oxide (ITO) intracavity contact. The TJ VCSEL shows a threshold current density (J{sub th}) of ∼3.5 kA/cm{sup 2}, compared to the ITO VCSEL J{sub th} of 8 kA/cm{sup 2}. The differential efficiency of the TJ VCSEL is also observed to be significantly higher than that of the ITO VCSEL, reaching a peak power of ∼550 μW, compared to ∼80 μW for the ITO VCSEL. Both VCSELs display filamentary lasing in the current aperture, which we believe to be predominantly a result of local variations in contact resistance, which may induce local variations in refractive index and free carrier absorption. Beyond the analyses of the lasing characteristics, we discuss the molecular-beam epitaxy (MBE) regrowth of the TJ, as well as its unexpected performance based on band-diagram simulations. Furthermore, we investigate the intrinsic advantages of using a TJ intracavity contact in a VCSEL using a 1D mode profile analysis to approximate the threshold modal gain and general loss contributions in the TJ and ITO VCSEL.

  15. R&W Club Frederick Hosts 4th Annual Golf Tournament Benefiting The Children’s Inn at NIH | Poster

    Cancer.gov

    The R&W Club Frederick’s 4th Annual Golf Tournament to benefit the Children’s Inn at NIH teed off on time despite cloudy weather and scattered showers. Employees from NCI at Frederick, the main NIH campus, and Leidos Biomed, along with family and friends, came to enjoy an afternoon at the beautiful Maryland National Golf Club in Middletown and to support a wonderful charity.

  16. R&W Club Frederick Hosts Second Annual Golf Tourney for The Children’s Inn | Poster

    Cancer.gov

    By Carolynne Keenan, Contributing Writer On Sept. 8, more than 40 NCI at Frederick and Leidos Biomedical Research employees, along with family and friends, swapped work clothes for golf gear at Maryland National Golf Club in Middletown. The golfers didn’t just play for fun; they participated in the second annual R&W Club Frederick Golf Tournament to support The Children’s Inn at NIH.

  17. R&W Club Frederick Hosts 4th Annual Golf Tournament Benefiting The Children’s Inn at NIH | Poster

    Cancer.gov

    The R&W Club Frederick’s 4th Annual Golf Tournament to benefit the Children’s Inn at NIH teed off on time despite cloudy weather and scattered showers. Employees from NCI at Frederick, the main NIH campus, and Leidos Biomed, along with family and friends, came to enjoy an afternoon at the beautiful Maryland National Golf Club in Middletown and to support a wonderful charity.

  18. R&W Club Frederick Hosts Second Annual Golf Tourney for The Children’s Inn | Poster

    Cancer.gov

    By Carolynne Keenan, Contributing Writer On Sept. 8, more than 40 NCI at Frederick and Leidos Biomedical Research employees, along with family and friends, swapped work clothes for golf gear at Maryland National Golf Club in Middletown. The golfers didn’t just play for fun; they participated in the second annual R&W Club Frederick Golf Tournament to support The Children’s Inn at NIH.

  19. High quality factor indium oxide mechanical microresonators

    SciTech Connect

    Bartolomé, Javier Cremades, Ana; Piqueras, Javier

    2015-11-09

    The mechanical resonance behavior of as-grown In{sub 2}O{sub 3} microrods has been studied in this work by in-situ scanning electron microscopy (SEM) electrically induced mechanical oscillations. Indium oxide microrods grown by a vapor–solid method are naturally clamped to an aluminum oxide ceramic substrate, showing a high quality factor due to reduced energy losses during mechanical vibrations. Quality factors of more than 10{sup 5} and minimum detectable forces of the order of 10{sup −16} N/Hz{sup 1/2} demonstrate their potential as mechanical microresonators for real applications. Measurements at low-vacuum using the SEM environmental operation mode were performed to study the effect of extrinsic damping on the resonators behavior. The damping coefficient has been determined as a function of pressure.

  20. Negative Magnetoresistance in Amorphous Indium Oxide Wires

    PubMed Central

    Mitra, Sreemanta; Tewari, Girish C; Mahalu, Diana; Shahar, Dan

    2016-01-01

    We study magneto-transport properties of several amorphous Indium oxide nanowires of different widths. The wires show superconducting transition at zero magnetic field, but, there exist a finite resistance at the lowest temperature. The R(T) broadening was explained by available phase slip models. At low field, and far below the superconducting critical temperature, the wires with diameter equal to or less than 100 nm, show negative magnetoresistance (nMR). The magnitude of nMR and the crossover field are found to be dependent on both temperature and the cross-sectional area. We find that this intriguing behavior originates from the interplay between two field dependent contributions. PMID:27876859

  1. Nanoscale guiding and shaping of indium droplets

    NASA Astrophysics Data System (ADS)

    DÄ browski, Maciej; Dai, Yanan; Hocevar, Moïra; Frolov, Sergey; Petek, Hrvoje

    2016-12-01

    We present time-resolved microscopy of motion and shape transformation of liquid indium (In) sessile droplets on InAs(001) surface. For temperatures up to 800 K, the droplets spontaneously move across the crystal undergoing stick-slip motion that is strongly affected by atomic steps and coalescence events. Above a critical temperature of around 800 K, the droplets stop moving and further increase in temperature causes them to change shape progressively from spherical to rectangular. The process of shape transformation is coherent, reversible and associated with temperature dependent wetting of the surface as well as crystalline anisotropy dependent arsenic solvation and evaporation rates. The etched rectangular substrate depressions formed under the droplets, giving them a rectangular shape, reveal unusual rheology with deeper regions at the corners. Our high spatial resolution measurements link the macroscopic behavior of the metallic droplets with the microscopic topography features and can be used for the metallic liquid droplet nano-manipulation.

  2. Negative Magnetoresistance in Amorphous Indium Oxide Wires

    NASA Astrophysics Data System (ADS)

    Mitra, Sreemanta; Tewari, Girish C.; Mahalu, Diana; Shahar, Dan

    2016-11-01

    We study magneto-transport properties of several amorphous Indium oxide nanowires of different widths. The wires show superconducting transition at zero magnetic field, but, there exist a finite resistance at the lowest temperature. The R(T) broadening was explained by available phase slip models. At low field, and far below the superconducting critical temperature, the wires with diameter equal to or less than 100 nm, show negative magnetoresistance (nMR). The magnitude of nMR and the crossover field are found to be dependent on both temperature and the cross-sectional area. We find that this intriguing behavior originates from the interplay between two field dependent contributions.

  3. Doping Profiles for Indium Antimonide Magnetoresistors

    NASA Astrophysics Data System (ADS)

    Partin, D. L.; Heremans, J.; Thrush, C. M.

    1997-03-01

    Indium antimonide is of interest for magnetoresistors in position sensors. These sensors are fabricated as thin film elements in order to increase the device impedance. The InSb is doped n-type to stabilize the electron density against temperature changes. This involves tradeoffs, since ionized donors scatter electrons, reducing their mobility and hence reducing the device sensitivity to a magnetic field. Optimizing the sensitivity involved three steps. The InSb is undoped for the first 10 to 20 percent of the film thickness, forming a buffer from the lattice mismatched substrate. The doping in the middle layer of the film has a doping gradient. Finally, a thin contact layer is more heavily doped to reduce contact resistance.

  4. Growth and Characterization of Single Crystalline InN Grown on GaN by RF Sputtering for Robust Schottky Contacts

    NASA Astrophysics Data System (ADS)

    Harotoonian, Vache; Woodall, Jerry M.

    2016-12-01

    High-quality, single crystal wurtzite InN films were fabricated by radio-frequency magnetron reactive sputtering on GaN templates. The sputtered InN films in this study were about 100 nm thick. Atomic force microscopy analysis revealed the sputtered InN film had root-mean-square surface roughness of about 0.4 nm, which is comparable to the underlying GaN template. Coupled x-ray diffraction (XRD) measurements confirmed the (0001) preferred growth orientation and ω-rocking curve full-width-half-maximum (FWHM) = 0.85° for the symmetrical (0002) diffraction peak. The present InN film has the best crystal quality in terms of narrower FWHM of XRD rocking curve among reported sputtered InN thin films. In-plane and out-of-plane XRD measurements revealed a relaxed film. Room temperature Hall Effect measurements showed mobility of 110 cm2/V.s and electron concentration of 1-2 × 1020/cm3. The feasibility of utilizing a cost effective and productive method of sputtering to form robust Schottky contacts to GaN using InN, an immiscible and metallic-like semiconductor, was explored.

  5. Current transport in W and WSI{sub x} ohmic contacts to InGaN and InN

    SciTech Connect

    Vartuli, C.B.; Pearton, S.J.; Abernathy, C.R.

    1997-10-01

    The temperature dependence of the specific contact resistance of W and WSi{sub 0.44} contacts on n{sup +} In{sub 0.65}Ga{sub 0.35}N and InN was measured in the range -50 {degrees}C to 125 {degrees}C. The results were compared to theoretical values for different conduction mechanisms, to further elucidate the conduction mechanism in these contact schemes for all but as-deposited metal to InN where thermionic emission appears to be the dominant mechanism. The contacts were found to produce low specific resistance ohmic contacts to InGaN at room temperature, e{sup c} {approximately} 10{sup -7} {Omega} {center_dot} cm{sup 2} for W and e{sub c} of 4x 10{sup -7} {Omega} {center_dot} cm{sup 2} for WSi{sub x}. InN metallized with W produced ohmic contacts with e{sub c} {approximately} 10{sup -7} {Omega} {center_dot} cm{sup 2} and e{sub c} {approximately} 10{sup -6} {Omega} {center_dot} cm{sup 2} for WSi{sub x} at room temperature.

  6. Morphology and arrangement of InN nanocolumns deposited by radio-frequency sputtering: Effect of the buffer layer

    NASA Astrophysics Data System (ADS)

    Monteagudo-Lerma, L.; Valdueza-Felip, S.; Núñez-Cascajero, A.; Ruiz, A.; González-Herráez, M.; Monroy, E.; Naranjo, F. B.

    2016-01-01

    We present the structural and optical properties of (0001)-oriented nanocolumnar films of InN deposited on c-sapphire substrates by radio-frequency reactive sputtering. It is observed that the column density and dimensions are highly dependent on the growth parameters of the buffer layer. We investigate four buffer layers consisting of (i) 30 nm of low-growth-rate InN, (ii) 30 nm of AlN deposited on the unbiased substrate (us), (iii) 30 nm of AlN deposited on the reverse-biased substrate (bs), and (iv) a 60-nm-thick bilayer consisting of 30-nm-thick bs-AlN deposited on top of 30-nm-thick us-AlN. Differences in the layer nucleation process due to the buffer layer induce variations of the column density in the range of (2.5-16)×109 cm-2, and of the column diameter in the range of 87-176 nm. Best results in terms of mosaicity are obtained using the bs-AlN buffer layer, which leads to a full width at half-maximum of the InN(0002) rocking curve of 1.2°. A residual compressive strain is still present in the nanocolumns. All samples exhibit room temperature photoluminescence emission at ~1.6 eV, and an apparent optical band gap at ~1.7 eV estimated from linear optical transmittance measurements.

  7. Nitride superluminescent diodes with broadened emission spectrum fabricated using laterally patterned substrate.

    PubMed

    Kafar, A; Stanczyk, S; Sarzynski, M; Grzanka, S; Goss, J; Targowski, G; Nowakowska-Siwinska, A; Suski, T; Perlin, P

    2016-05-02

    We demonstrate InGaN/GaN superluminescent diodes with broadened emission spectra fabricated on surface-shaped bulk GaN (0001) substrates. The patterning changes the local vicinal angle linearly along the device waveguide, which results in an indium incorporation profile in InGaN quantum wells. The structure was investigated by microphotoluminescence mapping, showing a shift of central emission wavelength from 413 nm to 430 nm. Spectral full width at half maximum of processed superluminescent diodes is equal to 6.1 nm, while the reference chips show 3.4 nm. This approach may open the path for using nitride devices in applications requiring broad emission spectrum and high beam quality, such as optical coherence tomography.

  8. Short Wavelength LED Based on III-V Nitride and its Applications

    NASA Astrophysics Data System (ADS)

    Shibata, Naoki; Uemura, Toshiya; Yamaguchi, Hisao; Yasukawa, Takemasa

    The short wavelength LED (“TG Purple”) based on III-V nitride semiconductors is established in addition to blue and green ones. This short wavelength LED is realized by adjusting indium chemical content of the well layer. Light output power of “TG Purple” is high and FWHM (full width at half maximum) is narrow. “TG Purple” is applied to light source of the white LED. Combination of “TG Purple” and various phosphors can generate white light with high luminous intensity and good color rendering. “TG Purple” is also applied to light source of air-purifier. This air-purifier is being offered as standard equipment in luxury automotives and several applications of this system are widely utilized in room air conditioners and refrigerators.

  9. Fabrication of LED based on III-V nitride and its applications

    NASA Astrophysics Data System (ADS)

    Shibata, Naoki; Uemura, Toshiya; Yamaguchi, Hisao; Yasukawa, Takemasa

    2003-11-01

    Short wavelength LED (TG Purple) based on III-V nitride semiconductors is established in addition to blue and green. This short wavelength LED is realized by adjusting the indium chemical content of the well layer. Light output power of TG Purple is high and FWHM is narrow. TG Purple is applied to light sources of white LED. Combination of TG Purple and various phosphors can generate white light with high luminous intensity and good color rendering. TG Purple is also applied to light sources of air-purifiers. Air-purifiers have become standard equipments for luxury-car models. Also, several applications of this system are widely utilized in room air conditioners and refrigerators. (

  10. Gallium Nitride Nanowires and Heterostructures: Toward Color-Tunable and White-Light Sources.

    PubMed

    Kuykendall, Tevye R; Schwartzberg, Adam M; Aloni, Shaul

    2015-10-14

    Gallium-nitride-based light-emitting diodes have enabled the commercialization of efficient solid-state lighting devices. Nonplanar nanomaterial architectures, such as nanowires and nanowire-based heterostructures, have the potential to significantly improve the performance of light-emitting devices through defect reduction, strain relaxation, and increased junction area. In addition, relaxation of internal strain caused by indium incorporation will facilitate pushing the emission wavelength into the red. This could eliminate inefficient phosphor conversion and enable color-tunable emission or white-light emission by combining blue, green, and red sources. Utilizing the waveguiding modes of the individual nanowires will further enhance light emission, and the properties of photonic structures formed by nanowire arrays can be implemented to improve light extraction. Recent advances in synthetic methods leading to better control over GaN and InGaN nanowire synthesis are described along with new concept devices leading to efficient white-light emission.

  11. Electrical transport properties of single undoped and n-type doped InN nanowires.

    PubMed

    Richter, T; Lüth, H; Schäpers, Th; Meijers, R; Jeganathan, K; Estévez Hernández, S; Calarco, R; Marso, M

    2009-10-07

    Electrical transport properties of undoped and n-type doped InN nanowires grown by molecular beam epitaxy were studied by current-voltage and back-gate field-effect transistor measurements. The current-voltage characteristics show ohmic behavior in the temperature range between 4 and 300 K. Down to about 120 K a linear decrease in resistance with temperature is observed. The investigation of a large number of nanowires revealed for undoped as well as doped wires an approximately linear relation between the normalized conductance and diameter for wires with a diameter below 100 nm. This shows that the main conduction takes place in the tubular surface accumulation layer of the wires. In contrast, for doped wires with a diameter larger than 100 nm a quadratic dependence of conduction on the diameter was found, which is attributed to bulk conductance as the main contribution. The successful doping of the wires is confirmed by an enhanced conduction and by the results of the back-gate field-effect transistor measurements.

  12. Hole transport and photoluminescence in Mg-doped InN

    SciTech Connect

    Miller, N.; Ager III, J. W.; Smith III, H. M.; Mayer, M. A.; Yu, K. M.; Haller, E. E.; Walukiewicz, W.; Schaff, W. J.; Gallinat, C.; Koblmuller, G.; Speck, J. S.

    2010-03-24

    Hole conductivity and photoluminescence were studied in Mg-doped InN films grown by molecular beam epitaxy. Because surface electron accumulation interferes with carrier type determination by electrical measurements, the nature of the majority carriers in the bulk of the films was determined using thermopower measurements. Mg concentrations in a"window" from ca. 3 x 1017 to 1 x 1019 cm-3 produce hole-conducting, p-type films as evidenced by a positive Seebeck coecient. This conclusion is supported by electrolyte-based capacitance voltage measurements and by changes in the overall mobility observed by Hall effect, both of which are consistent with a change from surface accumulation on an n-type film to surface inversion on a p-type film. The observed Seebeck coefficients are understood in terms of a parallel conduction model with contributions from surface and bulk regions. In partially compensated films with Mg concentrations below the window region, two peaks are observed in photoluminescence at 672 meV and at 603 meV. They are attributed to band-to-band and band-to-acceptor transitions, respectively, and an acceptor binding energy of ~;;70 meV is deduced. In hole-conducting films with Mg concentrations in the window region, no photoluminescence is observed; this is attributed to electron trapping by deep states which are empty for Fermi levels close to the valence band edge.

  13. Evaluation of testing strategies for the radiation tolerant ATLAS n +-in-n pixel sensor

    NASA Astrophysics Data System (ADS)

    Klaiber-Lodewigs, Jonas M.; Atlas Pixel Collaboration

    2003-10-01

    The development of particle tracker systems for high fluence environments in new high-energy physics experiments raises new challenges for the development, manufacturing and reliable testing of radiation tolerant components. The ATLAS pixel detector for use at the LHC, CERN, is designed to cover an active sensor area of 1.8 m2 with 1.1×10 8 read-out channels usable for a particle fluence up to 10 15 cm-2 ( 1 MeV neutron equivalent) and an ionization dose up to 500 kGy of mainly charged hadron radiation. To cope with such a harsh environment the ATLAS Pixel Collaboration has developed a radiation hard n +-in-n silicon pixel cell design with a standard cell size of 50×400 μm2. Using this design on an oxygenated silicon substrate, sensor production has started in 2001. This contribution describes results gained during the development of testing procedures of the ATLAS pixel sensor and evaluates quality assurance procedures regarding their relevance for detector operation in the ATLAS experiment. The specific set of tests discussed in detail measures sensor depletion, interface generation velocity, p-spray dose and biasing by punch-through mechanism and is designed to give insights into effects of irradiation with ionizing particles.

  14. Lattice dynamics of fct indium and hcp magnesium

    SciTech Connect

    Chen, X.M.; Xuan, Y.; Overhauser, A.W. )

    1991-01-15

    Phonon spectra of fct indium and hcp magnesium are calculated using the dynamic pseudopotential theory developed by Wang and Overhauser. Good agreement with experimental data is achieved with two adjustable pseudopotential parameters.

  15. Indium Ohmic Contacts to n-ZnSe,

    DTIC Science & Technology

    ELECTRIC CONTACTS, ANNEALING, AUGER ELECTRON SPECTROSCOPY , BACKSCATTERING, CHLORINE, DIFFRACTION, ELECTRON SPECTROSCOPY , FUNCTIONS, INDIUM... PHOTOELECTRONS , PURITY, RESISTANCE, TEMPERATURE, TEST AND EVALUATION, X RAY DIFFRACTION, MOLECULAR BEAMS, EPITAXIAL GROWTH, ZINC SELENIDES, DOPING.

  16. Method of manufacturing tin-doped indium oxide nanofibers

    DOEpatents

    Ozcan, Soydan; Naskar, Amit K

    2017-06-06

    A method of making indium tin oxide nanofibers includes the step of mixing indium and tin precursor compounds with a binder polymer to form a nanofiber precursor composition. The nanofiber precursor composition is co-formed with a supporting polymer to form a composite nanofiber having a precursor composition nanofiber completely surrounded by the supporting polymer composition. The supporting polymer composition is removed from the composite nanofiber to expose the precursor composition nanofiber. The precursor composition nanofiber is then heated in the presence of oxygen such as O.sub.2 to form indium tin oxide and to remove the binder polymer to form an indium tin oxide nanofiber. A method of making metal oxide nanofibers is also disclosed.

  17. Electrical studies on cubic boron nitride MIS structures

    NASA Astrophysics Data System (ADS)

    Daniel, Abishai

    A systematic investigation of the electrical properties of Metal-cBN-p-Silicon MIS structures through Capacitance-Voltage and Leakage Current measurements was undertaken. Electrical leakage measurements were performed using an HP4145B Semiconductor Parameter Analyzer and Capacitance-Voltage results were obtained using an LCZ Meter. Poole-Frenkel conduction was observed to be dominant in cBN MIS structures at low electric fields. Trap height values obtained for the films were ˜0.8 eV. Schottky conduction was observed to be the dominant conduction in predominantly cBN MIS structures. The gold-cBN barrier height was obtained to be ˜0.6 eV. For a fraction of MIS structures incorporating indium gate metal, Poole-Frenkel and Schottky conduction was observed. For other contacts evidence was observed of the alloying of indium with cBN resulting in Ohmic-like behavior analogous to the behavior of indium with GaAs. Evidence of the pinning of the Fermi level at the Metal-Insulator interface was obtained from the similarity of the gold-cBN and indium-cBN barrier heights. MIS structures incorporating tBN as the insulating layer exhibited similar conduction behavior to the cBN MIS structures. The gold-tBN barrier height obtained was ˜0.68 eV and the trap height obtained was ˜0.86 eV. A correlation between leakage current and RMS roughness of the surface was observed providing evidence of roughness mediated field enhancement at the metal insulator interface resulting in higher leakage currents. Leakage current of the cBN MIS structures at high electric fields exhibit a similar functional relationship to post Soft Breakdown I-V curves of ultrathin oxides at high electric fields. Hard Breakdown was not observed for our films at fields up to 2 MV/cm. This sets a lower bound for the breakdown field for our BN films. Resistivity values in the range 109 O-cm to 1012 O-cm were obtained for cBN and tBN films. To our knowledge, we obtained the first Capacitance-Voltage results on BN

  18. Ion-beam nitriding of steels

    NASA Technical Reports Server (NTRS)

    Salik, Joshua (Inventor); Hubbell, Theodore E. (Inventor)

    1987-01-01

    A surface of a steel substrate is nitrided without external heating by exposing it to a beam of nitrogen ions under low pressure, a pressure much lower than that employed for ion-nitriding. An ion source is used instead of a glow discharge. Both of these features reduce the introduction of impurities into the substrate surface.

  19. Infrared Plasmonics with Conductive Ternary Nitrides.

    PubMed

    Metaxa, C; Kassavetis, S; Pierson, J F; Gall, D; Patsalas, P

    2017-03-29

    Conductive transition metal nitrides are emerging as promising alternative plasmonic materials that are refractory and CMOS-compatible. In this work, we show that ternary transition metal nitrides of the B1 structure and consisting of a combination of group-IVb transition metal, such as Ti or Zr, and group III (Sc, Y, Al) or group II (Mg, Ca) elements can have tunable plasmonic activity in the infrared range in contrast to Ta-based ternary nitrides, which exhibit plasmonic performance in the visible and UV ranges. We consider the intrinsic quality factors of surface plasmon polariton for the ternary nitrides, and we calculate the dispersion of surface plasmon polariton and the field enhancement at the vicinity of nitride/silica interfaces. Based on these calculations, it is shown that among these nitrides the most promising are TixSc1-xN and TixMg1-xN. In particular, TixSc1-xN can have plasmonic activity in the usual telecom bands at 850, 1300, and 1550 nm. Still, these nitrides exhibit substantial electronic losses mostly due to fine crystalline grains that deteriorate the plasmonic field enhancement. This unequivocally calls for improved growth processes that would enable the fabrication of such ternary nitrides of high crystallinity.

  20. Low loss nitride ceramics for terahertz windows

    NASA Astrophysics Data System (ADS)

    Naftaly, M.; Greenslade, P. J.; Miles, R. E.; Evans, D.

    2009-09-01

    Terahertz frequency transmission measurements on ceramic boron nitride and aluminium nitride are described. The absorption coefficients and refractive indices of these materials show that they have high terahertz transparency, which together with their high melting temperatures and mechanical strength makes them particularly suitable for use as THz windows in high pressure and/or high temperature applications.