Sample records for band gap devices

  1. Thermophotovoltaic conversion using selective infrared line emitters and large band gap photovoltaic devices

    DOE Patents [OSTI]

    Brandhorst, Jr., Henry W. (Auburn, AL); Chen, Zheng (Auburn, AL)

    2000-01-01T23:59:59.000Z

    Efficient thermophotovoltaic conversion can be performed using photovoltaic devices with a band gap in the 0.75-1.4 electron volt range, and selective infrared emitters chosen from among the rare earth oxides which are thermally stimulated to emit infrared radiation whose energy very largely corresponds to the aforementioned band gap. It is possible to use thermovoltaic devices operating at relatively high temperatures, up to about 300.degree. C., without seriously impairing the efficiency of energy conversion.

  2. Voltage-matched, monolithic, multi-band-gap devices

    SciTech Connect (OSTI)

    Wanlass, Mark W.; Mascarenhas, Angelo

    2006-08-22T23:59:59.000Z

    Monolithic, tandem, photonic cells include at least a first semiconductor layer and a second semiconductor layer, wherein each semiconductor layer includes an n-type region, a p-type region, and a given band-gap energy. Formed within each semiconductor layer is a sting of electrically connected photonic sub-cells. By carefully selecting the numbers of photonic sub-cells in the first and second layer photonic sub-cell string(s), and by carefully selecting the manner in which the sub-cells in a first and second layer photonic sub-cell string(s) are electrically connected, each of the first and second layer sub-cell strings may be made to achieve one or more substantially identical electrical characteristics.

  3. Voltage-Matched, Monolithic, Multi-Band-Gap Devices

    DOE Patents [OSTI]

    Wanlass, M. W.; Mascarenhas, A.

    2006-08-22T23:59:59.000Z

    Monolithic, tandem, photonic cells include at least a first semiconductor layer and a second semiconductor layer, wherein each semiconductor layer includes an n-type region, a p-type region, and a given band-gap energy. Formed within each semiconductor layer is a string of electrically connected photonic sub-cells. By carefully selecting the numbers of photonic sub-cells in the first and second layer photonic sub-cell string(s), and by carefully selecting the manner in which the sub-cells in a first and second layer photonic sub-cell string(s) are electrically connected, each of the first and second layer sub-cell strings may be made to achieve one or more substantially identical electrical characteristics.

  4. Photovoltaic devices with low band gap polymers Eva Bundgaarda, Sean Shaheenb, David S. Ginleyb, Frederik C. Krebsa

    E-Print Network [OSTI]

    Photovoltaic devices with low band gap polymers Eva Bundgaarda, Sean Shaheenb, David S. Ginleyb, Colorado, USA Abstract Progress in organic photovoltaic devices has recently resulted in reported temperature, active area of the device and molecular weight of the polymer, on the photovoltaic response

  5. Periodic dielectric structure for production of photonic band gap and devices incorporating the same

    DOE Patents [OSTI]

    Ho, Kai-Ming (Ames, IA); Chan, Che-Ting (Ames, IA); Soukoulis, Costas (Ames, IA)

    1994-08-02T23:59:59.000Z

    A periodic dielectric structure which is capable of producing a photonic band gap and which is capable of practical construction. The periodic structure is formed of a plurality of layers, each layer being formed of a plurality of rods separated by a given spacing. The material of the rods contrasts with the material between the rods to have a refractive index contrast of at least two. The rods in each layer are arranged with their axes parallel and at a given spacing. Adjacent layers are rotated by 90.degree., such that the axes of the rods in any given layer are perpendicular to the axes in its neighbor. Alternating layers (that is, successive layers of rods having their axes parallel such as the first and third layers) are offset such that the rods of one are about at the midpoint between the rods of the other. A four-layer periocity is thus produced, and successive layers are stacked to form a three-dimensional structure which exhibits a photonic band gap. By virtue of forming the device in layers of elongate members, it is found that the device is susceptible of practical construction.

  6. Molecular beam epitaxy of n-type ZnS: A wide band gap emitter for heterojunction PV devices

    E-Print Network [OSTI]

    Atwater, Harry

    Molecular beam epitaxy of n-type ZnS: A wide band gap emitter for heterojunction PV devices Jeffrey and AZO transparent conductive oxides did not. Applications to novel PV devices incorporating low electron-ray diffraction, zinc compounds. I. INTRODUCTION The growing interest in scalable, thin-film photovoltaics (PV

  7. Wide-band-gap, alkaline-earth-oxide semiconductor and devices utilizing same

    DOE Patents [OSTI]

    Abraham, Marvin M. (Oak Ridge, TN); Chen, Yok (Oak Ridge, TN); Kernohan, Robert H. (Oak Ridge, TN)

    1981-01-01T23:59:59.000Z

    This invention relates to novel and comparatively inexpensive semiconductor devices utilizing semiconducting alkaline-earth-oxide crystals doped with alkali metal. The semiconducting crystals are produced by a simple and relatively inexpensive process. As a specific example, a high-purity lithium-doped MgO crystal is grown by conventional techniques. The crystal then is heated in an oxygen-containing atmosphere to form many [Li].degree. defects therein, and the resulting defect-rich hot crystal is promptly quenched to render the defects stable at room temperature and temperatures well above the same. Quenching can be effected conveniently by contacting the hot crystal with room-temperature air.

  8. Multiple gap photovoltaic device

    DOE Patents [OSTI]

    Dalal, Vikram L. (Newark, DE)

    1981-01-01T23:59:59.000Z

    A multiple gap photovoltaic device having a transparent electrical contact adjacent a first cell which in turn is adjacent a second cell on an opaque electrical contact, includes utilizing an amorphous semiconductor as the first cell and a crystalline semiconductor as the second cell.

  9. Low band gap polymers Organic Photovoltaics

    E-Print Network [OSTI]

    Low band gap polymers for Organic Photovoltaics Eva Bundgaard Ph.D. Dissertation Risø National Bundgaard Title: Low band gap polymers for Organic photovoltaics Department: The polymer department Report the area of organic photovoltaics are focusing on low band gap polymers, a type of polymer which absorbs

  10. Photonic band gap structure simulator

    DOE Patents [OSTI]

    Chen, Chiping; Shapiro, Michael A.; Smirnova, Evgenya I.; Temkin, Richard J.; Sirigiri, Jagadishwar R.

    2006-10-03T23:59:59.000Z

    A system and method for designing photonic band gap structures. The system and method provide a user with the capability to produce a model of a two-dimensional array of conductors corresponding to a unit cell. The model involves a linear equation. Boundary conditions representative of conditions at the boundary of the unit cell are applied to a solution of the Helmholtz equation defined for the unit cell. The linear equation can be approximated by a Hermitian matrix. An eigenvalue of the Helmholtz equation is calculated. One computation approach involves calculating finite differences. The model can include a symmetry element, such as a center of inversion, a rotation axis, and a mirror plane. A graphical user interface is provided for the user's convenience. A display is provided to display to a user the calculated eigenvalue, corresponding to a photonic energy level in the Brilloin zone of the unit cell.

  11. Narrow band gap amorphous silicon semiconductors

    DOE Patents [OSTI]

    Madan, A.; Mahan, A.H.

    1985-01-10T23:59:59.000Z

    Disclosed is a narrow band gap amorphous silicon semiconductor comprising an alloy of amorphous silicon and a band gap narrowing element selected from the group consisting of Sn, Ge, and Pb, with an electron donor dopant selected from the group consisting of P, As, Sb, Bi and N. The process for producing the narrow band gap amorphous silicon semiconductor comprises the steps of forming an alloy comprising amorphous silicon and at least one of the aforesaid band gap narrowing elements in amount sufficient to narrow the band gap of the silicon semiconductor alloy below that of amorphous silicon, and also utilizing sufficient amounts of the aforesaid electron donor dopant to maintain the amorphous silicon alloy as an n-type semiconductor.

  12. Band gap engineering at a semiconductor - crystalline oxide interface

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

    Moghadam, Jahangir-Moghadam; Shen, Xuan; Chrysler, Matthew; Ahmadi-Majlan, Kamyar; Su, Dong; Ngai, Joseph H.

    2015-03-01T23:59:59.000Z

    The epitaxial growth of crystalline oxides on semiconductors provides a pathway to introduce new functionalities to semiconductor devices. Key to integrating the functionalities of oxides onto semiconductors is controlling the band alignment at interfaces between the two materials. Here we apply principles of band gap engineering traditionally used at heterojunctions between conventional semiconductors to control the band offset between a single crystalline oxide and a semiconductor. Reactive molecular beam epitaxy is used to realize atomically abrupt and structurally coherent interfaces between SrZrxTi1-xO? and Ge, in which the band gap of the former is enhanced with Zr content x. We presentmore »structural and electrical characterization of SrZrxTi1-xO?-Ge heterojunctions and demonstrate a type-I band offset can be achieved. These results demonstrate that band gap engineering can be exploited to realize functional semiconductor crystalline oxide heterojunctions.« less

  13. Special purpose modes in photonic band gap fibers

    DOE Patents [OSTI]

    Spencer, James; Noble, Robert; Campbell, Sara

    2013-04-02T23:59:59.000Z

    Photonic band gap fibers are described having one or more defects suitable for the acceleration of electrons or other charged particles. Methods and devices are described for exciting special purpose modes in the defects including laser coupling schemes as well as various fiber designs and components for facilitating excitation of desired modes. Results are also presented showing effects on modes due to modes in other defects within the fiber and due to the proximity of defects to the fiber edge. Techniques and devices are described for controlling electrons within the defect(s). Various applications for electrons or other energetic charged particles produced by such photonic band gap fibers are also described.

  14. Band-Gap Engineering of Carbon Nanotubes with Grain Boundaries...

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

    Band-Gap Engineering of Carbon Nanotubes with Grain Boundaries. Band-Gap Engineering of Carbon Nanotubes with Grain Boundaries. Abstract: Structure and electronic properties of...

  15. Single-junction solar cells with the optimum band gap for terrestrial concentrator applications

    DOE Patents [OSTI]

    Wanlass, Mark W. (Golden, CO)

    1994-01-01T23:59:59.000Z

    A single-junction solar cell having the ideal band gap for terrestrial concentrator applications. Computer modeling studies of single-junction solar cells have shown that the presence of absorption bands in the direct spectrum has the effect of "pinning" the optimum band gap for a wide range of operating conditions at a value of 1.14.+-.0.02 eV. Efficiencies exceeding 30% may be possible at high concentration ratios for devices with the ideal band gap.

  16. Fabrication of photonic band gap materials

    DOE Patents [OSTI]

    Constant, Kristen (Ames, IA); Subramania, Ganapathi S. (Ames, IA); Biswas, Rana (Ames, IA); Ho, Kai-Ming (Ames, IA)

    2002-01-15T23:59:59.000Z

    A method for forming a periodic dielectric structure exhibiting photonic band gap effects includes forming a slurry of a nano-crystalline ceramic dielectric or semiconductor material and monodisperse polymer microspheres, depositing a film of the slurry on a substrate, drying the film, and calcining the film to remove the polymer microspheres therefrom. The film may be cold-pressed after drying and prior to calcining. The ceramic dielectric or semiconductor material may be titania, and the polymer microspheres may be polystyrene microspheres.

  17. Substrate-Induced Band-Gap Opening in Epitaxial Graphene

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

    Substrate-Induced Band-Gap Opening in Epitaxial Graphene Substrate-Induced Band-Gap Opening in Epitaxial Graphene Print Wednesday, 26 March 2008 00:00 Prospective challengers to...

  18. Direct band gap narrowing in highly doped Ge

    E-Print Network [OSTI]

    Han, Zhaohong

    Direct band gap narrowing in highly doped n-type Ge is observed through photoluminescence measurements by determining the spectrum peak shift. A linear relationship between the direct band gap emission and carrier concentration ...

  19. Single-junction solar cells with the optimum band gap for terrestrial concentrator applications

    DOE Patents [OSTI]

    Wanlass, M.W.

    1994-12-27T23:59:59.000Z

    A single-junction solar cell is described having the ideal band gap for terrestrial concentrator applications. Computer modeling studies of single-junction solar cells have shown that the presence of absorption bands in the direct spectrum has the effect of ''pinning'' the optimum band gap for a wide range of operating conditions at a value of 1.14[+-]0.02 eV. Efficiencies exceeding 30% may be possible at high concentration ratios for devices with the ideal band gap. 7 figures.

  20. Substrate-induced band gap opening in epitaxial graphene

    E-Print Network [OSTI]

    2008-01-01T23:59:59.000Z

    H.A. Electronic states of graphene nanoribbons studied withS.G. Louie. Energy gaps in graphene nanoribbons. Phys. Rev.band-gap engineering of graphene nanoribbons. Phys. Rev.

  1. acoustic band gaps: Topics by E-print Network

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

    type of phononic crystals manufactured Institute of Physics. DOI: 10.10631.2167794 The propagation of acoustic waves in periodic composite Deymier, Pierre 2 Acoustic band gap...

  2. Substrate-Induced Band-Gap Opening in Epitaxial Graphene

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

    Substrate-Induced Band-Gap Opening in Epitaxial Graphene Print Prospective challengers to silicon, the long-reigning king of semiconductors for computer chips and other electronic...

  3. SEMIEMPIRICAL MOLECULAR ORBITAL CALCULATIONS OF BAND GAPS OF CONJUGATED POLYMERS

    E-Print Network [OSTI]

    Goddard III, William A.

    SEMI­EMPIRICAL MOLECULAR ORBITAL CALCULATIONS OF BAND GAPS OF CONJUGATED POLYMERS Tahir Cagin Research and Development Center, Materials Labarotory, Polymer Branch, Wright Patterson AFB, Ohio 45433 geometries and energy band gaps of conjugated polymers. In this study, we used a modified version of semi

  4. One-dimensional electromagnetic band gap structures formed by discharge plasmas in a waveguide

    SciTech Connect (OSTI)

    Arkhipenko, V. I.; Simonchik, L. V., E-mail: l.simonchik@dragon.bas-net.by; Usachonak, M. S. [B.I. Stepanov Institute of Physics of the NAS of Belarus, Ave. Nezavisimostsi 68, 220072 Minsk (Belarus); Callegari, Th.; Sokoloff, J. [Université de Toulouse, UPS, INPT, LAPLACE, Laboratoire Plasma et Conversion d'Energie, 118 route de Narbonne, F-31062 Toulouse cedex 9 (France)

    2014-09-28T23:59:59.000Z

    We demonstrate the ability to develop one-dimensional electromagnetic band gap structure in X-band waveguide solely by using the positive columns of glow discharges in neon at the middle pressure. Plasma inhomogeneities are distributed uniformly along a typical X-band waveguide with cross section of 23?×?10?mm{sup 2}. It is shown that electron densities larger than 10{sup 14?}cm{sup ?3} are needed in order to create an effective one-dimensional electromagnetic band gap structure. Some applications for using the one-dimensional electromagnetic band gap structure in waveguide as a control of microwave (broadband filter and device for variation of pulse duration) are demonstrated.

  5. Feasibility of band gap engineering of pyrite FeS?

    E-Print Network [OSTI]

    Sun, Ruoshi

    We use first-principles computations to investigate whether the band gap of pyrite FeS? can be increased by alloying in order to make it a more effective photovoltaic material. In addition to the isostructural compounds ...

  6. Band gap engineering strategy via polarization rotation in perovskite ferroelectrics

    SciTech Connect (OSTI)

    Wang, Fenggong, E-mail: fenggong@sas.upenn.edu; Grinberg, Ilya; Rappe, Andrew M., E-mail: rappe@sas.upenn.edu [The Makineni Theoretical Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104–6323 (United States)

    2014-04-14T23:59:59.000Z

    We propose a strategy to engineer the band gaps of perovskite oxide ferroelectrics, supported by first principles calculations. We find that the band gaps of perovskites can be substantially reduced by as much as 1.2?eV through local rhombohedral-to-tetragonal structural transition. Furthermore, the strong polarization of the rhombohedral perovskite is largely preserved by its tetragonal counterpart. The B-cation off-center displacements and the resulting enhancement of the antibonding character in the conduction band give rise to the wider band gaps of the rhombohedral perovskites. The correlation between the structure, polarization orientation, and electronic structure lays a good foundation for understanding the physics of more complex perovskite solid solutions and provides a route for the design of photovoltaic perovskite ferroelectrics.

  7. Band gap engineering for graphene by using Na{sup +} ions

    SciTech Connect (OSTI)

    Sung, S. J.; Lee, P. R.; Kim, J. G.; Ryu, M. T.; Park, H. M.; Chung, J. W., E-mail: jwc@postech.ac.kr [Department of Physics, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)

    2014-08-25T23:59:59.000Z

    Despite the noble electronic properties of graphene, its industrial application has been hindered mainly by the absence of a stable means of producing a band gap at the Dirac point (DP). We report a new route to open a band gap (E{sub g}) at DP in a controlled way by depositing positively charged Na{sup +} ions on single layer graphene formed on 6H-SiC(0001) surface. The doping of low energy Na{sup +} ions is found to deplete the ?* band of graphene above the DP, and simultaneously shift the DP downward away from Fermi energy indicating the opening of E{sub g}. The band gap increases with increasing Na{sup +} coverage with a maximum E{sub g}?0.70?eV. Our core-level data, C 1s, Na 2p, and Si 2p, consistently suggest that Na{sup +} ions do not intercalate through graphene, but produce a significant charge asymmetry among the carbon atoms of graphene to cause the opening of a band gap. We thus provide a reliable way of producing and tuning the band gap of graphene by using Na{sup +} ions, which may play a vital role in utilizing graphene in future nano-electronic devices.

  8. On band gaps in photonic crystal fibers

    E-Print Network [OSTI]

    Shane Cooper; Ilia Kamotski; Valery Smyshlyaev

    2014-11-02T23:59:59.000Z

    We consider the Maxwell's system for a periodic array of dielectric `fibers' embedded into a `matrix', with respective electric permittivities $\\epsilon_0$ and $\\epsilon_1$, which serves as a model for cladding in photonic crystal fibers (PCF). The interest is in describing admissible and forbidden (gap) pairs $(\\omega,k)$ of frequencies $\\omega$ and propagation constants $k$ along the fibers, for a Bloch wave solution on the cross-section. We show that, for "pre-critical" values of $k(\\omega)$ i.e. those just below $\\omega (\\min\\{\\epsilon_0,\\epsilon_1\\}\\mu)^{1/2}$ (where $\\mu$ is the magnetic permeability assumed constant for simplicity), the coupling specific to the Maxwell's systems leads to a particular partially degenerating PDE system for the axial components of the electromagnetic field. Its asymptotic analysis allows to derive the limit spectral problem where the fields are constrained in one of the phases by Cauchy-Riemann type relations. We prove related spectral convergence. We finally give some examples, in particular of small size "arrow" fibers ($\\epsilon_0>\\epsilon_1$) where the existence of the gaps near appropriate "micro-resonances" is demonstrated by a further asymptotic analysis.

  9. Transformation Optics with Photonic Band Gap Media

    E-Print Network [OSTI]

    Urzhumov, Yaroslav A

    2010-01-01T23:59:59.000Z

    We introduce a class of optical media based on adiabatically modulated, dielectric-only, and potentially extremely low-loss, photonic crystals. The media we describe represent a generalization of the eikonal limit of transformation optics (TO). The foundation of the concept is the possibility to fit frequency isosurfaces in the k-space of photonic crystals with elliptic surfaces, allowing them to mimic the dispersion relation of light in anisotropic effective media. Photonic crystal cloaks and other TO devices operating at visible wavelengths can be constructed from optically transparent substances like glasses, whose attenuation coefficient can be as small as 10 dB/km, suggesting the TO design methodology can be applied to the development of optical devices not limited by the losses inherent to metal-based, passive metamaterials.

  10. Implications of mercury interactions with band-gap semiconductor oxides

    SciTech Connect (OSTI)

    Granite, E.J.; King, W.P.; Stanko, D.C.; Pennline, H.W.

    2008-09-01T23:59:59.000Z

    Titanium dioxide is a well-known photooxidation catalyst. It will oxidize mercury in the presence of ultraviolet light from the sun and oxygen and/or moisture to form mercuric oxide. Several companies manufacture self-cleaning windows. These windows have a transparent coating of titanium dioxide. The titanium dioxide is capable of destroying organic contaminants in air in the presence of ultraviolet light from the sun, thereby keeping the windows clean. The commercially available self-cleaning windows were used to sequester mercury from oxygen–nitrogen mixtures. Samples of the self-cleaning glass were placed into specially designed photo-reactors in order to study the removal of elemental mercury from oxygen–nitrogen mixtures resembling air. The possibility of removing mercury from ambient air with a self-cleaning glass apparatus is examined. The intensity of 365-nm ultraviolet light was similar to the natural intensity from sunlight in the Pittsburgh region. Passive removal of mercury from the air may represent an option in lieu of, or in addition to, point source clean-up at combustion facilities. There are several common band-gap semiconductor oxide photocatalysts. Sunlight (both the ultraviolet and visible light components) and band-gap semiconductor particles may have a small impact on the global cycle of mercury in the environment. The potential environmental consequences of mercury interactions with band-gap semiconductor oxides are discussed. Heterogeneous photooxidation might impact the global transport of elemental mercury emanating from flue gases.

  11. Transport band gap opening at metal–organic interfaces

    SciTech Connect (OSTI)

    Haidu, Francisc, E-mail: francisc.haidu@physik.tu-chemnitz.de; Salvan, Georgeta; Zahn, Dietrich R. T. [Semiconductor Physics, Technische Universität Chemnitz, D-09107 Chemnitz (Germany); Smykalla, Lars; Hietschold, Michael [Solid Surfaces Analysis, Technische Universität Chemnitz, D-09107 Chemnitz (Germany); Knupfer, Martin [Electronic and Optical Properties Department, IFW Dresden, D-01171 Dresden (Germany)

    2014-07-01T23:59:59.000Z

    The interface formation between copper phthalocyanine (CuPc) and two representative metal substrates, i.e., Au and Co, was investigated by the combination of ultraviolet photoelectron spectroscopy and inverse photoelectron spectroscopy. The occupied and unoccupied molecular orbitals and thus the transport band gap of CuPc are highly influenced by film thickness, i.e., molecule substrate distance. Due to the image charge potential given by the metallic substrates the transport band gap of CuPc “opens” from (1.4?±?0.3) eV for 1?nm thickness to (2.2?±?0.3) eV, and saturates at this value above 10?nm CuPc thickness. The interface dipoles with values of 1.2?eV and 1.0?eV for Au and Co substrates, respectively, predominantly depend on the metal substrate work functions. X-ray photoelectron spectroscopy measurements using synchrotron radiation provide detailed information on the interaction between CuPc and the two metal substrates. While charge transfer from the Au or Co substrate to the Cu metal center is present only at sub-monolayer coverages, the authors observe a net charge transfer from the molecule to the Co substrate for films in the nm range. Consequently, the Fermi level is shifted as in the case of a p-type doping of the molecule. This is, however, a competing phenomenon to the energy band shifts due to the image charge potential.

  12. Fluorine Substituted Conjugated Polymer of Medium Band Gap Yields 7% Efficiency in Polymer--Fullerene Solar Cells

    SciTech Connect (OSTI)

    Price, S C; Stuart, Andrew C.; Yang, L; Zhou, H; You, Wei

    2011-01-01T23:59:59.000Z

    Recent research advances on conjugated polymers for photovoltaic devices have focused on creating low band gap materials, but a suitable band gap is only one of many performance criteria required for a successful conjugated polymer. This work focuses on the design of two medium band gap (?2.0 eV) copolymers for use in photovoltaic cells which are designed to possess a high hole mobility and low highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels. The resulting fluorinated polymer PBnDT?FTAZ exhibits efficiencies above 7% when blended with [6,6]-phenyl C{sub 61}-butyric acid methyl ester in a typical bulk heterojunction, and efficiencies above 6% are still maintained at an active layer thicknesses of 1 ?m. PBnDT?FTAZ outperforms poly(3-hexylthiophene), the current medium band gap polymer of choice, and thus is a viable candidate for use in highly efficient tandem cells. PBnDT?FTAZ also highlights other performance criteria which contribute to high photovoltaic efficiency, besides a low band gap.

  13. Surface Plasmon Band Gap Sensor A new sensor for robust on-field biosensing (SEN 1)

    E-Print Network [OSTI]

    Arnaud Benahmed; Robert Lam; Chih-Ming Ho

    2006-01-01T23:59:59.000Z

    Networked Sensing Surface Plasmon Band Gap Sensor A newsensing concept Nanostructures for Surface Plasmon SensingSurface Plasmon are surface EM waves whose wavelength is

  14. PHYSICAL REVIEW B 90, 115209 (2014) Computational search for direct band gap silicon crystals

    E-Print Network [OSTI]

    Lee, Jooyoung

    2014-01-01T23:59:59.000Z

    of microns thick, while solar cells made from direct band gap materials (such as CdTe, CIGS, or CZTS) can

  15. Thermoelectric power measurements of wide band gap semiconducting Chul-Ho Lee,1

    E-Print Network [OSTI]

    Kim, Philip

    Thermoelectric power measurements of wide band gap semiconducting nanowires Chul-Ho Lee,1 Gyu online 13 January 2009 We investigated the temperature-dependent thermoelectric power TEP of individual concentration in wide band gap semiconducting nano- wires employing temperature-dependent thermoelectric power

  16. Light trapping design for low band-gap polymer solar cells

    E-Print Network [OSTI]

    John, Sajeev

    Light trapping design for low band-gap polymer solar cells Stephen Foster1,* and Sajeev John1,2 1 demonstrate numerically a 2-D nanostructured design for light trapping in a low band-gap polymer solar cell observe an enhancement in solar absorption of almost 40% relative to a planar cell. Improvements

  17. Band gap changes of GaN shocked to 13 GPa M. D. McCluskeya)

    E-Print Network [OSTI]

    McCluskey, Matthew

    Band gap changes of GaN shocked to 13 GPa M. D. McCluskeya) and Y. M. Gupta Institute for Shock, California 94304 Received 24 October 2001; accepted for publication 19 December 2001 The band gap of GaN in shock-wave experiments. Shock waves were generated by impacting the GaN samples with c-cut sapphire

  18. Utility-Scale Solar Power Converter: Agile Direct Grid Connect Medium Voltage 4.7-13.8 kV Power Converter for PV Applications Utilizing Wide Band Gap Devices

    SciTech Connect (OSTI)

    None

    2012-01-25T23:59:59.000Z

    Solar ADEPT Project: Satcon is developing a compact, lightweight power conversion device that is capable of taking utility-scale solar power and outputting it directly into the electric utility grid at distribution voltage levels—eliminating the need for large transformers. Transformers “step up” the voltage of the power that is generated by a solar power system so it can be efficiently transported through transmission lines and eventually “stepped down” to usable voltages before it enters homes and businesses. Power companies step up the voltage because less electricity is lost along transmission lines when the voltage is high and current is low. Satcon’s new power conversion devices will eliminate these heavy transformers and connect a utility-scale solar power system directly to the grid. Satcon’s modular devices are designed to ensure reliability—if one device fails it can be bypassed and the system can continue to run.

  19. Blueshift of optical band gap in ZnO thin films grown by metal-organic chemical-vapor deposition

    E-Print Network [OSTI]

    . INTRODUCTION Zinc oxide ZnO is a wide direct band-gap 3.37 eV semiconductor with a broad range of applications. Dimethylzinc DMZn , N2 gas, and high-purity O2 were used as the zinc source, carrier gas, and oxidizing agent including light-emitting devices,1 varistors,2 solar cells,3 and gas sensors.4 Moreover, ZnO is a promising

  20. X-Band Photonic Band-Gap Accelerator Structure Breakdown Experiment

    SciTech Connect (OSTI)

    Marsh, Roark A.; /MIT /MIT /NIFS, Gifu /JAERI, Kyoto /LLNL, Livermore; Shapiro, Michael A.; Temkin, Richard J.; /MIT; Dolgashev, Valery A.; Laurent, Lisa L.; Lewandowski, James R.; Yeremian, A.Dian; Tantawi, Sami G.; /SLAC

    2012-06-11T23:59:59.000Z

    In order to understand the performance of photonic band-gap (PBG) structures under realistic high gradient, high power, high repetition rate operation, a PBG accelerator structure was designed and tested at X band (11.424 GHz). The structure consisted of a single test cell with matching cells before and after the structure. The design followed principles previously established in testing a series of conventional pillbox structures. The PBG structure was tested at an accelerating gradient of 65 MV/m yielding a breakdown rate of two breakdowns per hour at 60 Hz. An accelerating gradient above 110 MV/m was demonstrated at a higher breakdown rate. Significant pulsed heating occurred on the surface of the inner rods of the PBG structure, with a temperature rise of 85 K estimated when operating in 100 ns pulses at a gradient of 100 MV/m and a surface magnetic field of 890 kA/m. A temperature rise of up to 250 K was estimated for some shots. The iris surfaces, the location of peak electric field, surprisingly had no damage, but the inner rods, the location of the peak magnetic fields and a large temperature rise, had significant damage. Breakdown in accelerator structures is generally understood in terms of electric field effects. These PBG structure results highlight the unexpected role of magnetic fields in breakdown. The hypothesis is presented that the moderate level electric field on the inner rods, about 14 MV/m, is enhanced at small tips and projections caused by pulsed heating, leading to breakdown. Future PBG structures should be built to minimize pulsed surface heating and temperature rise.

  1. Calculation of wakefields in a 17 GHz beam-driven photonic band-gap accelerator structure

    E-Print Network [OSTI]

    Hu, Min

    We present the theoretical analysis and computer simulation of the wakefields in a 17 GHz photonic band-gap (PBG) structure for accelerator applications. Using the commercial code CST Particle Studio, the fundamental ...

  2. Tunable frequency band-gap and pulse propagation in a strongly nonlinear diatomic chain

    E-Print Network [OSTI]

    E. B. Herbold; J. Kim; V. F. Nesterenko; S. Wang; C. Daraio

    2008-06-26T23:59:59.000Z

    One-dimensional nonlinear phononic crystals have been assembled from periodic diatomic chains of stainless steel cylinders alternated with Polytetrafluoroethylene (PTFE) spheres. We report the presence of acoustic band gaps in the dispersion relation of the linearized systems and study the transformation of single and multiple pulses in linear, nonlinear and strongly nonlinear regimes with numerical calculations and experiments. The limiting frequencies of the band gap are within the audible frequency range (20-20,000 Hz) and can be tuned by varying the particle's material properties, mass and initial compression. Pulses rapidly transform within very short distances from the impacted end due to the influence of the band gap in the linear and in nonlinear elastic chains. The effects of an in situ band gap created by a mean dynamic compression are observed in the strongly nonlinear wave regime.

  3. Band Gap Optimization of Two-Dimensional Photonic Crystals Using ...

    E-Print Network [OSTI]

    2009-07-10T23:59:59.000Z

    Jul 10, 2009 ... proven very important as device components for integrated optics ...... Inhibited spontaneous emission in solid-state physics and electronics.

  4. Energy Band-Gap Engineering of Graphene Nanoribbons Melinda Y. Han,1

    E-Print Network [OSTI]

    Kim, Philip

    , New York, New York 10027, USA 2 Department of Physics, Columbia University, New York, New York 10027Energy Band-Gap Engineering of Graphene Nanoribbons Melinda Y. Han,1 Barbaros O¨ zyilmaz,2 Yuanbo an energy gap near the charge neutrality point. Individual graphene layers are contacted with metal

  5. Multi-junction, monolithic solar cell using low-band-gap materials lattice matched to GaAs or Ge

    DOE Patents [OSTI]

    Olson, Jerry M. (Lakewood, CO); Kurtz, Sarah R. (Golden, CO); Friedman, Daniel J. (Lakewood, CO)

    2001-01-01T23:59:59.000Z

    A multi-junction, monolithic, photovoltaic solar cell device is provided for converting solar radiation to photocurrent and photovoltage with improved efficiency. The solar cell device comprises a plurality of semiconductor cells, i.e., active p/n junctions, connected in tandem and deposited on a substrate fabricated from GaAs or Ge. To increase efficiency, each semiconductor cell is fabricated from a crystalline material with a lattice constant substantially equivalent to the lattice constant of the substrate material. Additionally, the semiconductor cells are selected with appropriate band gaps to efficiently create photovoltage from a larger portion of the solar spectrum. In this regard, one semiconductor cell in each embodiment of the solar cell device has a band gap between that of Ge and GaAs. To achieve desired band gaps and lattice constants, the semiconductor cells may be fabricated from a number of materials including Ge, GaInP, GaAs, GaInAsP, GaInAsN, GaAsGe, BGaInAs, (GaAs)Ge, CuInSSe, CuAsSSe, and GaInAsNP. To further increase efficiency, the thickness of each semiconductor cell is controlled to match the photocurrent generated in each cell. To facilitate photocurrent flow, a plurality of tunnel junctions of low-resistivity material are included between each adjacent semiconductor cell. The conductivity or direction of photocurrent in the solar cell device may be selected by controlling the specific p-type or n-type characteristics for each active junction.

  6. Plasma process-induced band-gap modifications of a strained SiGe heterostructure

    E-Print Network [OSTI]

    Misra, Durgamadhab "Durga"

    Plasma process-induced band-gap modifications of a strained SiGe heterostructure P. K. Swain,a) S the strain of coherently strained SiGe. This work investigates the change in valence-band discontinuity in plasma-exposed SiGe films due to strain relaxation by a capacitance­voltage (C­V) profiling technique

  7. Indirect-to-direct band gap transition in relaxed and strained Ge{sub 1?x?y}Si{sub x}Sn{sub y} ternary alloys

    SciTech Connect (OSTI)

    Attiaoui, Anis; Moutanabbir, Oussama [Department of Engineering Physics, École Polytechnique de Montréal, Montréal, C.P. 6079, Succ. Centre-Ville, Montréal, Québec H3C 3A7 (Canada)

    2014-08-14T23:59:59.000Z

    Sn-containing group IV semiconductors create the possibility to independently control strain and band gap thus providing a wealth of opportunities to develop an entirely new class of low dimensional systems, heterostructures, and silicon-compatible electronic and optoelectronic devices. With this perspective, this work presents a detailed investigation of the band structure of strained and relaxed Ge{sub 1?x?y}Si{sub x}Sn{sub y} ternary alloys using a semi-empirical second nearest neighbors tight binding method. This method is based on an accurate evaluation of the deformation potential constants of Ge, Si, and ?-Sn using a stochastic Monte-Carlo approach as well as a gradient based optimization method. Moreover, a new and efficient differential evolution approach is also developed to accurately reproduce the experimental effective masses and band gaps. Based on this, we elucidated the influence of lattice disorder, strain, and composition on Ge{sub 1?x?y}Si{sub x}Sn{sub y} band gap energy and directness. For 0???x???0.4 and 0???y???0.2, we found that tensile strain lowers the critical content of Sn needed to achieve a direct band gap semiconductor with the corresponding band gap energies below 0.76?eV. This upper limit decreases to 0.43?eV for direct gap, fully relaxed ternary alloys. The obtained transition to direct band gap is given by y?>?0.605?×?x?+?0.077 and y?>?1.364?×?x?+?0.107 for epitaxially strained and fully relaxed alloys, respectively. The effects of strain, at a fixed composition, on band gap directness were also investigated and discussed.

  8. Band gap structure modification of amorphous anodic Al oxide film by Ti-alloying

    SciTech Connect (OSTI)

    Canulescu, S., E-mail: stec@fotonik.dtu.dk; Schou, J. [Department of Photonics Engineering, Technical University of Denmark, 4000 Roskilde (Denmark); Rechendorff, K.; Pleth Nielsen, L. [Danish Technological Institute, Kongsvang Alle 29, 8000 Aarhus (Denmark); Borca, C. N. [Paul Scherrer Institute, 5232 Villigen (Switzerland); Jones, N. C.; Hoffmann, S. V. [ISA, Department of Physics and Astronomy, Aarhus University, 8000 Aarhus (Denmark); Bordo, K.; Ambat, R. [Department of Mechanical Engineering, Technical University of Denmark, 2800 Kongens Lyngby (Denmark)

    2014-03-24T23:59:59.000Z

    The band structure of pure and Ti-alloyed anodic aluminum oxide has been examined as a function of Ti concentration varying from 2 to 20 at.?%. The band gap energy of Ti-alloyed anodic Al oxide decreases with increasing Ti concentration. X-ray absorption spectroscopy reveals that Ti atoms are not located in a TiO{sub 2} unit in the oxide layer, but rather in a mixed Ti-Al oxide layer. The optical band gap energy of the anodic oxide layers was determined by vacuum ultraviolet spectroscopy in the energy range from 4.1 to 9.2?eV (300–135?nm). The results indicate that amorphous anodic Al{sub 2}O{sub 3} has a direct band gap of 7.3?eV, which is about ?1.4?eV lower than its crystalline counterpart (single-crystal Al{sub 2}O{sub 3}). Upon Ti-alloying, extra bands appear within the band gap of amorphous Al{sub 2}O{sub 3}, mainly caused by Ti 3d orbitals localized at the Ti site.

  9. Method of manufacturing flexible metallic photonic band gap structures, and structures resulting therefrom

    DOE Patents [OSTI]

    Gupta, Sandhya (Bloomington, MN); Tuttle, Gary L. (Ames, IA); Sigalas, Mihail (Ames, IA); McCalmont, Jonathan S. (Ames, IA); Ho, Kai-Ming (Ames, IA)

    2001-08-14T23:59:59.000Z

    A method of manufacturing a flexible metallic photonic band gap structure operable in the infrared region, comprises the steps of spinning on a first layer of dielectric on a GaAs substrate, imidizing this first layer of dielectric, forming a first metal pattern on this first layer of dielectric, spinning on and imidizing a second layer of dielectric, and then removing the GaAs substrate. This method results in a flexible metallic photonic band gap structure operable with various filter characteristics in the infrared region. This method may be used to construct multi-layer flexible metallic photonic band gap structures. Metal grid defects and dielectric separation layer thicknesses are adjusted to control filter parameters.

  10. Defect assistant band alignment transition from staggered to broken gap in mixed As/Sb tunnel field effect transistor heterostructure

    E-Print Network [OSTI]

    Yener, Aylin

    .3As heterointerface. As a result, the band alignment was converted from staggered gap to broken gap-to-source voltage, VGS. As the SS of a MOSFET is governed by the transport mechanism of thermionic-emission over

  11. Direct measurements of band gap grading in polycrystalline CIGS solar cells

    E-Print Network [OSTI]

    Heinrich, M P; Zhang, Y; Kiowski, O; Powalla, M; Lemmer, U; Slobodskyy, A

    2010-01-01T23:59:59.000Z

    We present direct measurements of depth-resolved band gap variations of CuIn(1-x)Ga(x)Se2 thin-film solar cell absorbers. A new measurement technique combining parallel measurements of local thin-film interference and spectral photoluminescence was developed for this purpose. We find sample-dependent correlation parameters between measured band gap depth and composition profiles, and emphasize the importance of direct measurements. These results bring a quantitative insight into the electronic properties of the solar cells and open a new way to analyze parameters that determine the efficiency of solar cells.

  12. Direct measurements of band gap grading in polycrystalline CIGS solar cells

    E-Print Network [OSTI]

    M. P. Heinrich; Z-H. Zhang; Y. Zhang; O. Kiowski; M. Powalla; U. Lemmer; A. Slobodskyy

    2010-09-20T23:59:59.000Z

    We present direct measurements of depth-resolved band gap variations of CuIn(1-x)Ga(x)Se2 thin-film solar cell absorbers. A new measurement technique combining parallel measurements of local thin-film interference and spectral photoluminescence was developed for this purpose. We find sample-dependent correlation parameters between measured band gap depth and composition profiles, and emphasize the importance of direct measurements. These results bring a quantitative insight into the electronic properties of the solar cells and open a new way to analyze parameters that determine the efficiency of solar cells.

  13. Gallium arsenide-based ternary compounds and multi-band-gap solar cell research

    SciTech Connect (OSTI)

    Vernon, S. (Spire Corp., Bedford, MA (United States))

    1993-02-01T23:59:59.000Z

    Aim of this contract is the achievement of a high-efficiency, low-cost solar cell. The basic approach to the problem is centered upon the heteroepitaxial growth of a III-V compound material onto a single-crystal silicon wafer. The growth technique employed is metalorganic chemical vapor deposition. The silicon wafer may serve as a mechanical substrate and ohmic contact for a single-junction device, or may contain a p-n junction of its own and form the bottom cell of a two junction tandem solar cell structure. The III-V material for the single-junction case is GaAs and for the two-junction case is either GaAlAs or GaAsP, either material having the proper composition to yield a band gap of approximately 1.7 eV. Results achieved in this contract include the following: (1) a 17.6% efficient GaAs-on-Si solar cell; (2) an 18.5% efficient GaAs-on-Si concentrator solar cell at 400 suns; (3) a 24.8% efficient GaAs-on-GaAs solar cell; (4) a 28.7% efficient GaAs-on-GaAs concentrator solar cell at 200 suns; (5) measurement of the effects of dislocation density and emitter doping on GaAs cells; and (6) improvements in the growth process to achieve reproducible thin AlGaAs window layers with low recombination velocities and environmental stability.

  14. Surface Plasmon Polariton Assisted Optical Switching in Noble Metal Nanoparticle Systems: A Sub-Band Gap Approach

    E-Print Network [OSTI]

    Dhara, S

    2015-01-01T23:59:59.000Z

    In a proposed book chapter surface plasmon polariton assisted optical switching in noble metal nanoparticle systems is discussed in the sub-band gap formalism.

  15. New Reconfigurable Power Divider Based on Radial Waveguide and Cylindrical Electromagnetic Band Gap Structure for Low

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Structure for Low Power and Low Cost Smart Antenna Systems Halim Boutayeb, Paul Watson and Toby Kemp AntennaNew Reconfigurable Power Divider Based on Radial Waveguide and Cylindrical Electromagnetic Band Gap halim.boutayeb@huawei.com Abstract--A new low power and low cost technique is proposed for designing

  16. Exploiting pattern transformation to tune phononic band gaps in a two-dimensional granular crystal

    E-Print Network [OSTI]

    ) cylinders is investigated numerically. This system was previously shown to undergo a pattern transformation with uniaxial compression by Go¨ncu¨ et al. [Soft Matter 7, 2321 (2011)]. The dispersion relations, or elastic waves in certain frequency ranges known as band gaps is an important feature of these materials

  17. The Electrical and Band-Gap Properties of Amorphous Zinc-Indium-Tin Oxide Thin Films

    E-Print Network [OSTI]

    Shahriar, Selim

    MRSEC The Electrical and Band-Gap Properties of Amorphous Zinc-Indium-Tin Oxide Thin Films D Science & Engineering Center For zinc-indium-tin oxide (ZITO) films, grown by pulsed-laser deposition was replaced by substitution with zinc and tin in equal molar proportions (co-substitution). All ZITO films

  18. Photonic band gap of a graphene-embedded quarter-wave stack

    SciTech Connect (OSTI)

    Fan, Yuancheng [Ames Laboratory; Wei, Zeyong [Tongji University; Li, Hongqiang [Tongji University; Chen, Hong [Tongji University; Soukoulis, Costas M [Ames Laboratory

    2013-12-10T23:59:59.000Z

    Here, we present a mechanism for tailoring the photonic band structure of a quarter-wave stack without changing its physical periods by embedding conductive sheets. Graphene is utilized and studied as a realistic, two-dimensional conductive sheet. In a graphene-embedded quarter-wave stack, the synergic actions of Bragg scattering and graphene conductance contributions open photonic gaps at the center of the reduced Brillouin zone that are nonexistent in conventional quarter-wave stacks. Such photonic gaps show giant, loss-independent density of optical states at the fixed lower-gap edges, of even-multiple characteristic frequency of the quarter-wave stack. The conductive sheet-induced photonic gaps provide a platform for the enhancement of light-matter interactions.

  19. Band gap reduction in GaNSb alloys due to the anion mismatch

    SciTech Connect (OSTI)

    Veal, T.D.; Piper, L.F.J.; Jollands, S.; Bennett, B.R.; Jefferson, P.H.; Thomas, P.A.; McConville, C.F.; Murdin, B.N.; Buckle, L.; Smith, G.W.; Ashley, T. [Department of Physics, University of Warwick, Coventry, CV4 7AL (United Kingdom); School of Electronics and Physical Sciences, University of Surrey, Guildford, GU2 5XH (United Kingdom); QinetiQ Ltd., St. Andrews Road, Malvern, Worcestershire, WR14 3PS (United Kingdom)

    2005-09-26T23:59:59.000Z

    The structural and optoelectronic properties in GaN{sub x}Sb{sub 1-x} alloys (0{<=}x<0.02) grown by molecular-beam epitaxy on both GaSb substrates and AlSb buffer layers on GaAs substrates are investigated. High-resolution x-ray diffraction (XRD) and reciprocal space mapping indicate that the GaN{sub x}Sb{sub 1-x} epilayers are of high crystalline quality and the alloy composition is found to be independent of substrate, for identical growth conditions. The band gap of the GaNSb alloys is found to decrease with increasing nitrogen content from absorption spectroscopy. Strain-induced band-gap shifts, Moss-Burstein effects, and band renormalization were ruled out by XRD and Hall measurements. The band-gap reduction is solely due to the substitution of dilute amounts of highly electronegative nitrogen for antimony, and is greater than observed in GaNAs with the same N content.

  20. Band gap tuning in transition metal oxides by site-specific substitution

    DOE Patents [OSTI]

    Lee, Ho Nyung; Chisholm, Jr., Matthew F; Jellison, Jr., Gerald Earle; Singh, David J; Choi, Woo Seok

    2013-12-24T23:59:59.000Z

    A transition metal oxide insulator composition having a tuned band gap includes a transition metal oxide having a perovskite or a perovskite-like crystalline structure. The transition metal oxide includes at least one first element selected form the group of Bi, Ca, Ba, Sr, Li, Na, Mg, K, Pb, and Pr; and at least one second element selected from the group of Ti, Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Ru, Rh, Hf, Ta, W, Re, Os, Ir, and Pt. At least one correlated insulator is integrated into the crystalline structure, including REMO.sub.3, wherein RE is at least one Rare Earth element, and wherein M is at least one element selected from the group of Co, V, Cr, Ni, Mn, and Fe. The composition is characterized by a band gap of less of 4.5 eV.

  1. Fabrication of Ceramic Layer-by-Layer Infrared Wavelength Photonic Band Gap Crystals

    SciTech Connect (OSTI)

    Henry Hao-Chuan Kang

    2004-12-19T23:59:59.000Z

    Photonic band gap (PBG) crystals, also known as photonic crystals, are periodic dielectric structures which form a photonic band gap that prohibit the propagation of electromagnetic (EM) waves of certain frequencies at any incident angles. Photonic crystals have several potential applications including zero-threshold semiconductor lasers, the inhibition of spontaneous emission, dielectric mirrors, and wavelength filters. If defect states are introduced in the crystals, light can be guided from one location to another or even a sharp bending of light in micron scale can be achieved. This generates the potential for optical waveguide and optical circuits, which will contribute to the improvement in the fiber-optic communications and the development of high-speed computers.

  2. Periodic dielectric structure for production of photonic band gap and method for fabricating the same

    DOE Patents [OSTI]

    Ozbay, E.; Tuttle, G.; Michel, E.; Ho, K.M.; Biswas, R.; Chan, C.T.; Soukoulis, C.

    1995-04-11T23:59:59.000Z

    A method is disclosed for fabricating a periodic dielectric structure which exhibits a photonic band gap. Alignment holes are formed in a wafer of dielectric material having a given crystal orientation. A planar layer of elongate rods is then formed in a section of the wafer. The formation of the rods includes the step of selectively removing the dielectric material of the wafer between the rods. The formation of alignment holes and layers of elongate rods and wafers is then repeated to form a plurality of patterned wafers. A stack of patterned wafers is then formed by rotating each successive wafer with respect to the next-previous wafer, and then placing the successive wafer on the stack. This stacking results in a stack of patterned wafers having a four-layer periodicity exhibiting a photonic band gap. 42 figures.

  3. Pre-Stressed Viscoelastic Composites: Effective Incremental Moduli and Band-Gap Tuning

    SciTech Connect (OSTI)

    Parnell, William J. [School of Mathematics, Alan Turing Building, University of Manchester, Manchester, M13 9PL (United Kingdom)

    2010-09-30T23:59:59.000Z

    We study viscoelastic wave propagation along pre-stressed nonlinear elastic composite bars. In the pre-stressed state we derive explicit forms for the effective incremental storage and loss moduli with dependence on the pre-stress. We also derive a dispersion relation for the effective wavenumber in the case of arbitrary frequency, hence permitting a study of viscoelastic band-gap tuning via pre-stress.

  4. Engineering of the band gap and optical properties of thin films of yttrium hydride

    SciTech Connect (OSTI)

    You, Chang Chuan; Mongstad, Trygve; Maehlen, Jan Petter; Karazhanov, Smagul, E-mail: smagulk@ife.no [Institute for Energy Technology, P.O. Box 40, NO-2027 Kjeller (Norway)

    2014-07-21T23:59:59.000Z

    Thin films of oxygen-containing yttrium hydride show photochromic effect at room temperature. In this work, we have studied structural and optical properties of the films deposited at different deposition pressures, discovering the possibility of engineering the optical band gap by variation of the oxygen content. In sum, the transparency of the films and the wavelength range of photons triggering the photochromic effect can be controlled by variation of the deposition pressure.

  5. Band gap tunning in BN-doped graphene systems with high carrier mobility

    SciTech Connect (OSTI)

    Kaloni, T. P.; Schwingenschlögl, U., E-mail: udo.schwingenschlogl@kaust.edu.sa [KAUST, PSE Division, Thuwal 23955-6900 (Saudi Arabia); Joshi, R. P.; Adhikari, N. P. [Central Department of Physics, Tribhuvan University, Kirtipur, Kathmandu (Nepal)

    2014-02-17T23:59:59.000Z

    Using density functional theory, we present a comparative study of the electronic properties of BN-doped graphene monolayer, bilayer, trilayer, and multilayer systems. In addition, we address a superlattice of pristine and BN-doped graphene. Five doping levels between 12.5% and 75% are considered, for which we obtain band gaps from 0.02?eV to 2.43?eV. We demonstrate a low effective mass of the charge carriers.

  6. Microwave band gap and cavity mode in spoof-insulator-spoof waveguide with multiscale structured surface

    E-Print Network [OSTI]

    Zhang, Qiang; Han, Dezhuan; Qin, Fei Fei; Zhang, Xiao Ming; Yao, Yong

    2015-01-01T23:59:59.000Z

    We propose a multiscale spoof-insulator-spoof (SIS) waveguide by introducing periodic geometry modulation in the wavelength scale to a SIS waveguide made of perfect electric conductor. The MSIS consists of multiple SIS subcells. The dispersion relationship of the fundamental guided mode of the spoof surface plasmon polaritons (SSPPs) is studied analytically within the small gap approximation. It is shown that the multiscale SIS possesses microwave band gap (MBG) due to the Bragg scattering. The "gap maps" in the design parameter space are provided. We demonstrate that the geometry of the subcells can efficiently adjust the effective refraction index of the elementary SIS and therefore further control the width and the position of the MBG. The results are in good agreement with numerical calculations by the finite element method (FEM). For finite-sized MSIS of given geometry in the millimeter scale, FEM calculations show that the first-order symmetric SSPP mode has zero transmission in the MBG within frequency...

  7. Photonic-band-gap properties for two-component slow light

    SciTech Connect (OSTI)

    Ruseckas, J.; Kudriasov, V.; Juzeliunas, G.; Unanyan, R. G.; Otterbach, J.; Fleischhauer, M. [Institute of Theoretical Physics and Astronomy, Vilnius University, A. Gostauto 12, Vilnius 01108 (Lithuania); Fachbereich Physik and Research Center OPTIMAS, Technische Universitaet Kaiserslautern, Kaiserslautern D-67663 (Germany)

    2011-06-15T23:59:59.000Z

    We consider two-component ''spinor'' slow light in an ensemble of atoms coherently driven by two pairs of counterpropagating control laser fields in a double tripod-type linkage scheme. We derive an equation of motion for the spinor slow light (SSL) representing an effective Dirac equation for a massive particle with the mass determined by the two-photon detuning. By changing the detuning the atomic medium acts as a photonic crystal with a controllable band gap. If the frequency of the incident probe light lies within the band gap, the light experiences reflection from the sample and can tunnel through it. For frequencies outside the band gap, the transmission and reflection probabilities oscillate with the increasing length of the sample. In both cases the reflection takes place into the complementary mode of the probe field. We investigate the influence of the finite excited state lifetime on the transmission and reflection coefficients of the probe light. We discuss possible experimental implementations of the SSL using alkali-metal atoms such as rubidium or sodium.

  8. Blocking a wave: Frequency band gaps in ice shelves with periodic crevasses

    E-Print Network [OSTI]

    Julian Freed-Brown; Jason M. Amundson; Douglas R. MacAyeal; Wendy W. Zhang

    2011-12-14T23:59:59.000Z

    We assess how the propagation of high-frequency elastic-flexural waves through an ice shelf is modified by the presence of spatially periodic crevasses. Analysis of the normal modes supported by the ice shelf with and without crevasses reveals that a periodic crevasse distribution qualitatively changes the mechanical response. The normal modes of an ice shelf free of crevasses are evenly distributed as a function of frequency. In contrast, the normal modes of a crevasse-ridden ice shelf are distributed unevenly. There are "band gaps", frequency ranges over which no eigenmodes exist. A model ice shelf that is 50 km in lateral extent and 300 m thick with crevasses spaced 500 m apart has a band gap from 0.2 to 0.38 Hz. This is a frequency range relevant for ocean wave/ice-shelf interactions. When the outermost edge of the crevassed ice shelf is oscillated at a frequency within the band gap, the ice shelf responds very differently from a crevasse-free ice shelf. The flexural motion of the crevassed ice shelf is confined to a small region near the outermost edge of the ice shelf and effectively "blocked" from reaching the interior.

  9. Blocking a wave: Frequency band gaps in ice shelves with periodic crevasses

    E-Print Network [OSTI]

    Freed-Brown, Julian; MacAyeal, Douglas R; Zhang, Wendy W

    2011-01-01T23:59:59.000Z

    We assess how the propagation of high-frequency elastic-flexural waves through an ice shelf is modified by the presence of spatially periodic crevasses. Analysis of the normal modes supported by the ice shelf with and without crevasses reveals that a periodic crevasse distribution qualitatively changes the mechanical response. The normal modes of an ice shelf free of crevasses are evenly distributed as a function of frequency. In contrast, the normal modes of a crevasse-ridden ice shelf are distributed unevenly. There are "band gaps", frequency ranges over which no eigenmodes exist. A model ice shelf that is 50 km in lateral extent and 300 m thick with crevasses spaced 500 m apart has a band gap from 0.2 to 0.38 Hz. This is a frequency range relevant for ocean wave/ice-shelf interactions. When the outermost edge of the crevassed ice shelf is oscillated at a frequency within the band gap, the ice shelf responds very differently from a crevasse-free ice shelf. The flexural motion of the crevassed ice shelf is c...

  10. High efficiency thin-film multiple-gap photovoltaic device

    DOE Patents [OSTI]

    Dalal, Vikram L. (Newark, DE)

    1983-01-01T23:59:59.000Z

    A photovoltaic device includes at least two solar cells made from Group IV elements or their alloys in the amorphous state mounted on a substrate. The outermost or first cell has a larger bandgap than the second cell. Various techniques are utilized to improve the efficiency of the device.

  11. Wave propagation in ordered, disordered, and nonlinear photonic band gap materials

    SciTech Connect (OSTI)

    Lidorikis, Elefterios

    1999-12-10T23:59:59.000Z

    Photonic band gap materials are artificial dielectric structures that give the promise of molding and controlling the flow of optical light the same way semiconductors mold and control the electric current flow. In this dissertation the author studied two areas of photonic band gap materials. The first area is focused on the properties of one-dimensional PBG materials doped with Kerr-type nonlinear material, while, the second area is focused on the mechanisms responsible for the gap formation as well as other properties of two-dimensional PBG materials. He first studied, in Chapter 2, the general adequacy of an approximate structure model in which the nonlinearity is assumed to be concentrated in equally-spaced very thin layers, or 6-functions, while the rest of the space is linear. This model had been used before, but its range of validity and the physical reasons for its limitations were not quite clear yet. He performed an extensive examination of many aspects of the model's nonlinear response and comparison against more realistic models with finite-width nonlinear layers, and found that the d-function model is quite adequate, capturing the essential features in the transmission characteristics. The author found one exception, coming from the deficiency of processing a rigid bottom band edge, i.e. the upper edge of the gaps is always independent of the refraction index contrast. This causes the model to miss-predict that there are no soliton solutions for a positive Kerr-coefficient, something known to be untrue.

  12. Electro-optic device with gap-coupled electrode

    DOE Patents [OSTI]

    Deri, Robert J.; Rhodes, Mark A.; Bayramian, Andrew J.; Caird, John A.; Henesian, Mark A.; Ebbers, Christopher A.

    2013-08-20T23:59:59.000Z

    An electro-optic device includes an electro-optic crystal having a predetermined thickness, a first face and a second face. The electro-optic device also includes a first electrode substrate disposed opposing the first face. The first electrode substrate includes a first substrate material having a first thickness and a first electrode coating coupled to the first substrate material. The electro-optic device further includes a second electrode substrate disposed opposing the second face. The second electrode substrate includes a second substrate material having a second thickness and a second electrode coating coupled to the second substrate material. The electro-optic device additionally includes a voltage source electrically coupled to the first electrode coating and the second electrode coating.

  13. Effect of silver incorporation in phase formation and band gap tuning of tungsten oxide thin films

    SciTech Connect (OSTI)

    Jolly Bose, R.; Kumar, R. Vinod; Sudheer, S. K.; Mahadevan Pillai, V. P. [Department of Optoelectronics, University of Kerala, Kariyavattom, Thiruvananthapuram, Kerala 695581 (India); Reddy, V. R.; Ganesan, V. [UGC - DAE Consortium for Scientific Research, Khandwa Road, Indore 452017, Madhyapradesh (India)

    2012-12-01T23:59:59.000Z

    Silver incorporated tungsten oxide thin films are prepared by RF magnetron sputtering technique. The effect of silver incorporation in micro structure evolution, phase enhancement, band gap tuning and other optical properties are investigated using techniques such as x-ray diffraction, micro-Raman spectroscopy, atomic force microscopy, scanning electron microscopy, energy dispersive x-ray spectroscopy, and UV-Visible spectroscopy. Effect of silver addition in phase formation and band gap tuning of tungsten oxide thin films are investigated. It is found that the texturing and phase formation improves with enhancement in silver content. It is also found that as the silver incorporation enhances the thickness of the films increases at the same time the strain in the film decreases. Even without annealing the desired phase can be achieved by doping with silver. A broad band centered at the wavelength 437 nm is observed in the absorption spectra of tungsten oxide films of higher silver incorporation and this can be attributed to surface plasmon resonance of silver atoms present in the tungsten oxide matrix. The transmittance of the films is decreased with increase in silver content which can be due to increase in film thickness, enhancement of scattering, and absorption of light caused by the increase of grain size, surface roughness and porosity of films and enhanced absorption due to surface plasmon resonance of silver. It is found that silver can act as the seed for the growth of tungsten oxide grains and found that the grain size increases with silver content which in turn decreases the band gap of tungsten oxide from 3.14 eV to 2.70 eV.

  14. Engineering direct-indirect band gap transition in wurtzite GaAs nanowires through size and uniaxial strain

    E-Print Network [OSTI]

    Copple, Andrew; Peng, Xihong; 10.1063/1.4718026

    2012-01-01T23:59:59.000Z

    Electronic structures of wurtzite GaAs nanowires in the [0001] direction were studied using first-principles calculations. It was found that the band gap of GaAs nanowires experience a direct-to-indirect transition when the diameter of the nanowires is smaller than ~28 {\\AA}. For those thin GaAs nanowires with an indirect band gap, it was found that the gap can be tuned to be direct if a moderate external uniaxial strain is applied. Both tensile and compressive strain can trigger the indirect-to-direct gap transition. The critical strains for the gap-transition are determined by the energy crossover of two states in conduction bands.

  15. DESIGN, GROWTH, FABRICATION AND CHARACTERIZATION OF HIGH-BAND GAP InGaN/GaN SOLAR CELLS

    E-Print Network [OSTI]

    Honsberg, Christiana

    DESIGN, GROWTH, FABRICATION AND CHARACTERIZATION OF HIGH-BAND GAP InGaN/GaN SOLAR CELLS Omkar Jani1 with a band gap of 2.4 eV or greater. InxGa1-xN is one of a few alloys that can meet this key requirement. InGaN.4 eV. InGaN has the appropriate optical properties and has been well demonstrated for light

  16. Analysis of plasma-magnetic photonic crystal with a tunable band gap

    SciTech Connect (OSTI)

    Mehdian, H.; Mohammadzahery, Z.; Hasanbeigi, A. [Department of Physics and Plasma Research Institute of Tarbiat Moallem University, 49 Dr Mofatteh Avenue, Tehran 15614 (Iran, Islamic Republic of)

    2013-04-15T23:59:59.000Z

    In this paper, electromagnetic wave propagation through the one-dimensional plasma-magnetic photonic crystal in the presence of external magnetic field has been analyzed. The dispersion relation, transmission and reflection coefficients have been obtained by using the transfer matrix method. It is investigated how photonic band gap of photonic crystals will be tuned when both dielectric function {epsilon} and magnetic permeability {mu} of the constitutive materials, depend on applied magnetic field. This is shown by one dimensional photonic crystals consisting of plasma and ferrite material layers stacked alternately.

  17. Waveguides in three-dimensional metallic photonic band-gap materials

    SciTech Connect (OSTI)

    Sigalas, M.M.; Biswas, R.; Ho, K.M.; Soukoulis, C.M. [Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States)] [Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States); Crouch, D.D. [Advanced Electromagnetic Technologies Center, Raytheon Corporation, Rancho Cucamonga, California 91729 (United States)] [Advanced Electromagnetic Technologies Center, Raytheon Corporation, Rancho Cucamonga, California 91729 (United States)

    1999-08-01T23:59:59.000Z

    We theoretically investigate waveguide structures in three-dimensional metallic photonic band-gap (MPBG) materials. The MPBG materials used in this study consist of a three-dimensional mesh of metallic wires embedded in a dielectric. An {ital L}-shaped waveguide is created by removing part of the metallic wires. Using finite difference time domain simulations, we found that an 85{percent} transmission efficiency can be achieved through the 90{degree} bend with just three unit cell thickness MPBG structures. thinsp {copyright} {ital 1999} {ital The American Physical Society}

  18. Indirect-direct band gap transition through electric tuning in bilayer MoS{sub 2}

    SciTech Connect (OSTI)

    Zhang, Z. Y.; Si, M. S., E-mail: sims@lzu.edu.cn; Wang, Y. H.; Gao, X. P. [Key laboratory for Magnetism and Magnetic Materials of the Ministry of Education, School of Physical Science and Technology, Lanzhou University, Lanzhou 730 000 (China)] [Key laboratory for Magnetism and Magnetic Materials of the Ministry of Education, School of Physical Science and Technology, Lanzhou University, Lanzhou 730 000 (China); Sung, Dongchul; Hong, Suklyun [Graphene Research Institute, Sejong University, Seoul 143 747 (Korea, Republic of)] [Graphene Research Institute, Sejong University, Seoul 143 747 (Korea, Republic of); He, Junjie [Department of Physics, Xiangtan University, Hunan 411 105 (China)] [Department of Physics, Xiangtan University, Hunan 411 105 (China)

    2014-05-07T23:59:59.000Z

    We investigate the electronic properties of bilayer MoS{sub 2} exposed to an external electric field by using first-principles calculations. It is found that a larger interlayer distance, referring to that by standard density functional theory (DFT) with respect to that by DFT with empirical dispersion corrections, makes indirect-direct band gap transition possible by electric control. We show that external electric field effectively manipulates the valence band contrast between the K- and ?-valleys by forming built-in electric dipole fields, which realizes an indirect-direct transition before a semiconductor-metal transition happens. Our results provide a novel efficient access to tune the electronic properties of two-dimensional layered materials.

  19. Band gap corrections for molecules and solids using Koopmans theorem and Wannier functions

    E-Print Network [OSTI]

    Ma, Jie

    2015-01-01T23:59:59.000Z

    We have proposed a method for correcting the Kohn-Sham eigen energies in the density functional theory (DFT) based on the Koopmans theorem using Wannier functions. The method provides a general approach applicable for molecules and solids for electronic structure calculations. It does not have any adjustable parameters and the computational cost is at the DFT level. For solids, the calculated eigen energies agree well with the experiments for not only the band gaps, but also the energies of other valence and conduction bands. For molecules, the calculated eigen energies agree well with the experimental ionization potentials and electron affinities, and show better trends than the traditional Delta-self-consistent-field (?SCF) results.

  20. Effects of surface termination on the band gap of ultrabright Si29 nanoparticles: Experiments and computational models

    E-Print Network [OSTI]

    Braun, Paul

    Effects of surface termination on the band gap of ultrabright Si29 nanoparticles: Experiments constituting a H-terminated reconstructed Si surface was recently proposed as a structural prototype termination with a N linkage in butylamine and O linkage in pentane . The emission band for N-termination

  1. Fermion space charge in narrow-band gap semiconductors, Weyl semimetals and around highly charged nuclei

    E-Print Network [OSTI]

    Eugene B. Kolomeisky; Joseph P. Straley; Hussain Zaidi

    2013-10-15T23:59:59.000Z

    The field of charged impurities in narrow-band gap semiconductors and Weyl semimetals can create electron-hole pairs when the total charge $Ze$ of the impurity exceeds a value $Z_{c}e$. The particles of one charge escape to infinity, leaving a screening space charge. The result is that the observable dimensionless impurity charge $Q_{\\infty}$ is less than $Z$ but greater than $Z_{c}$. There is a corresponding effect for nuclei with $Z >Z_{c} \\approx 170$, however in the condensed matter setting we find $Z_{c} \\simeq 10$. Thomas-Fermi theory indicates that $Q_{\\infty} = 0$ for the Weyl semimetal, but we argue that this is a defect of the theory. For the case of a highly-charged recombination center in a narrow band-gap semiconductor (or of a supercharged nucleus), the observable charge takes on a nearly universal value. In Weyl semimetals the observable charge takes on the universal value $Q_{\\infty} = Z_{c}$ set by the reciprocal of material's fine structure constant.

  2. Integrated Polymer Optoelectronic Time Delay Device for an X-band Phased Array Antenna System

    E-Print Network [OSTI]

    Chen, Ray

    Integrated Polymer Optoelectronic Time Delay Device for an X-band Phased Array Antenna System Brie ABSTRACT A 4-bit polymer optoelectronic true time delay device is demonstrated. The device is composed of monolithically integrated, low loss, passive polymer waveguide delay lines and 2x2 polymer thermo-optic switches

  3. Band gap and band parameters of InN and GaN from quasiparticle energy calculations based on exact-exchange density-functional theory

    E-Print Network [OSTI]

    Band gap and band parameters of InN and GaN from quasiparticle energy calculations based on exact; published online 20 October 2006 The authors have studied the electronic structure of InN and GaN employing. © 2006 American Institute of Physics. DOI: 10.1063/1.2364469 The group III-nitrides AlN, GaN, and In

  4. Catalyzed Water Oxidation by Solar Irradiation of Band-Gap-Narrowed Semiconductors (Part 1. Overview).

    SciTech Connect (OSTI)

    Fujita,E.; Khalifah, P.; Lymar, S.; Muckerman, J.T.; Rodgriguez, J.

    2008-03-18T23:59:59.000Z

    The objectives of this report are: (1) Investigate the catalysis of water oxidation by cobalt and manganese hydrous oxides immobilized on titania or silica nanoparticles, and dinuclear metal complexes with quinonoid ligands in order to develop a better understanding of the critical water oxidation chemistry, and rationally search for improved catalysts. (2) Optimize the light-harvesting and charge-separation abilities of stable semiconductors including both a focused effort to improve the best existing materials by investigating their structural and electronic properties using a full suite of characterization tools, and a parallel effort to discover and characterize new materials. (3) Combine these elements to examine the function of oxidation catalysts on Band-Gap-Narrowed Semiconductor (BGNSC) surfaces and elucidate the core scientific challenges to the efficient coupling of the materials functions.

  5. Electronic structure of Pt based topological Heusler compounds with C1{sub b} structure and 'zero band gap'

    SciTech Connect (OSTI)

    Ouardi, Siham; Shekhar, Chandra; Fecher, Gerhard H.; Kozina, Xeniya; Stryganyuk, Gregory; Felser, Claudia [Institut fuer Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universitaet, D-55099 Mainz (Germany); Ueda, Shigenori; Kobayashi, Keisuke [NIMS Beamline Station at SPring-8, National Institute for Materials Science, Hyogo 679-5148 (Japan)

    2011-05-23T23:59:59.000Z

    Besides of their well-known wide range of properties it was recently shown that many of the heavy Heusler semiconductors with 1:1:1 composition and C1{sub b} structure exhibit a zero band gap behavior and are topological insulators induced by their inverted band structure. In the present study, the electronic structure of the Heusler compounds PtYSb and PtLaBi was investigated by bulk sensitive hard x-ray photoelectron spectroscopy. The measured valence band spectra are clearly resolved and in well agreement to the first-principles calculations of the electronic structure of the compounds. The experimental results give clear evidence for the zero band gap state.

  6. Maximum Theoretical Efficiency Limit of Photovoltaic Devices: Effect of Band Structure on Excited State Entropy

    E-Print Network [OSTI]

    Osterloh, Frank

    Maximum Theoretical Efficiency Limit of Photovoltaic Devices: Effect of Band Structure on Excited a theoretical limit for the maximum energy conversion efficiency of single junction photovoltaic cells for the efficiency variations observed for real photovoltaic devices today.4-6 Here, we show that the extractable

  7. Calculation of semiconductor band gaps with the M06-L density functional Yan Zhao and Donald G. Truhlara

    E-Print Network [OSTI]

    Truhlar, Donald G

    2009 The performance of the M06-L density functional has been tested for band gaps in seven,13 that is designed for main group thermo- chemistry, transition metal bonding, thermochemical kinet- ics in group-4, group 3­5, and metal oxide semiconductors. In Sec. II, we describe the test sets

  8. Multipole-cancellation mechanism for high-Q cavities in the absence of a complete photonic band gap

    E-Print Network [OSTI]

    Multipole-cancellation mechanism for high-Q cavities in the absence of a complete photonic band gap in the lowest-order term s of the multipole far-field radiation expansion. We focus on the system of photonic-order term s in a multipole expansion of the far-field radiation, distinct from the near- field multipole

  9. Band-gap grading in Cu(In,Ga)Se2 solar cells M. Gloeckler and J. R. Sites

    E-Print Network [OSTI]

    Sites, James R.

    Band-gap grading in Cu(In,Ga)Se2 solar cells M. Gloeckler and J. R. Sites Department of Physics solar cells, and some researchers have asserted that these fields can enhance performance to show that (1) there can be a beneficial effect of grading, (2) in standard thick- ness CIGS cells

  10. Elastic and viscoelastic effects in rubber/air acoustic band gap structures: A theoretical and experimental study

    E-Print Network [OSTI]

    Deymier, Pierre

    Elastic and viscoelastic effects in rubber/air acoustic band gap structures: A theoretical rubber/air phononic crystal structures is investigated theoretically and experimentally. We introduce in a solid rubber matrix, as well as an array of rubber cylinders in an air matrix, are shown to behave

  11. Optical bistability and phase transitions in a doped photonic band-gap material Sajeev John and Tran Quang

    E-Print Network [OSTI]

    John, Sajeev

    in a pseudophotonic band gap PBG to an applied laser field. It is shown that in the case when the variance of resonant reactive ion etching techniques. The relative dif- ficulty in drilling to a depth of more than a few unit

  12. Here, we present the fabrication and use of plastic Photonic Band Gap Bragg fibres in photonic textiles for applications in

    E-Print Network [OSTI]

    Skorobogatiy, Maksim

    Here, we present the fabrication and use of plastic Photonic Band Gap Bragg fibres in photonic­section, Bragg fibres feature periodic sequence of layers of two distinct plastics. Under ambient illumination SCHICKER2 , NING GUO1 , CHARLES DUBOIS3 , RACHEL WINGFIELD2 & MAKSIM SKOROBOGATIY1 COLOUR-ON-DEMAND

  13. Band gap tuning in GaN through equibiaxial in-plane strains S. K. Yadav,2

    E-Print Network [OSTI]

    Alpay, S. Pamir

    in photovoltaics and light emission diodes LEDs . The InGaN system has been intensively studied during the past to the large atomic size mismatch between Ga and In.3 Thus, other methods to tune the band gap are needed for potential appli- cations of GaN and related materials systems. It is well-known that the structure

  14. Method for implantation of high dopant concentrations in wide band gap materials

    DOE Patents [OSTI]

    Usov, Igor (Los Alamos, NM); Arendt, Paul N. (Los Alamos, NM)

    2009-09-15T23:59:59.000Z

    A method that combines alternate low/medium ion dose implantation with rapid thermal annealing at relatively low temperatures. At least one dopant is implanted in one of a single crystal and an epitaxial film of the wide band gap compound by a plurality of implantation cycles. The number of implantation cycles is sufficient to implant a predetermined concentration of the dopant in one of the single crystal and the epitaxial film. Each of the implantation cycles includes the steps of: implanting a portion of the predetermined concentration of the one dopant in one of the single crystal and the epitaxial film; annealing one of the single crystal and the epitaxial film and implanted portion at a predetermined temperature for a predetermined time to repair damage to one of the single crystal and the epitaxial film caused by implantation and activates the implanted dopant; and cooling the annealed single crystal and implanted portion to a temperature of less than about 100.degree. C. This combination produces high concentrations of dopants, while minimizing the defect concentration.

  15. Wide-band-gap InAlAs solar cell for an alternative multijunction approach Marina S. Leite,1,a

    E-Print Network [OSTI]

    Atwater, Harry

    Wide-band-gap InAlAs solar cell for an alternative multijunction approach Marina S. Leite,1,a Robyn; published online 28 February 2011 We have fabricated an In0.52Al0.48As solar cell lattice-matched to In-free InxAl1-xAs alloyed layers were used to fabricate the single junction solar cell. Photoluminescence

  16. SPECTROSCOPIE DE DEFAUTS -LUMINESCENCE I. THE ANALYSIS OF WIDE BAND GAP SEMICONDUCTORS

    E-Print Network [OSTI]

    Boyer, Edmond

    on analysis depend very much on the device. In semiconductors, light emitting diodes (LEDs) are formed from pn

  17. Band Gap Shift of GaN under Uniaxial Strain Compression H. Y. Peng, M. D. McCluskey, Y. M. Gupta, M. Kneissl1

    E-Print Network [OSTI]

    McCluskey, Matthew

    Band Gap Shift of GaN under Uniaxial Strain Compression H. Y. Peng, M. D. McCluskey, Y. M. Gupta, M.S.A. ABSTRACT The band-gap shift of GaN:Mg epilayers on (0001)-oriented sapphire was studied as a function is approximately 0.026 eV/GPa. Combining this result with the known behavior of wurtzite GaN under hydrostatic

  18. Shock-induced band-gap shift in GaN: Anisotropy of the deformation potentials H. Y. Peng, M. D. McCluskey,* and Y. M. Gupta

    E-Print Network [OSTI]

    McCluskey, Matthew

    Shock-induced band-gap shift in GaN: Anisotropy of the deformation potentials H. Y. Peng, M. D. Mc Alto, California 94304, USA Received 19 October 2004; published 24 March 2005 The band-gap shift of GaN=1.9 eV, and D4=-1.0 eV. These values indicate that the deformation potentials in wurtzite GaN

  19. Ultra-high-frequency chaos in a time-delay electronic device with band-limited feedback

    E-Print Network [OSTI]

    Illing, Lucas

    Ultra-high-frequency chaos in a time-delay electronic device with band-limited feedback Lucas- dynamical electronic device. It consists of a transistor-based nonlinearity, commercially of such a device, we explore the dynamics of an electronic circuit that consists of a simple transistor

  20. Novel wide band gap materials for highly efficient thin film tandem solar cells

    SciTech Connect (OSTI)

    Brian E. Hardin, Stephen T. Connor, Craig H. Peters

    2012-06-11T23:59:59.000Z

    Tandem solar cells (TSCs), which use two or more materials to absorb sunlight, have achieved power conversion efficiencies of >25% versus 11-20% for commercialized single junction solar cell modules. The key to widespread commercialization of TSCs is to develop the wide-band, top solar cell that is both cheap to fabricate and has a high open-circuit voltage (i.e. >1V). Previous work in TSCs has generally focused on using expensive processing techniques with slow growth rates resulting in costs that are two orders of magnitude too expensive to be used in conventional solar cell modules. The objective of the PLANT PV proposal was to investigate the feasibility of using Ag(In,Ga)Se2 (AIGS) as the wide-bandgap absorber in the top cell of a thin film tandem solar cell (TSC). Despite being studied by very few in the solar community, AIGS solar cells have achieved one of the highest open-circuit voltages within the chalcogenide material family with a Voc of 949mV when grown with an expensive processing technique (i.e. Molecular Beam Epitaxy). PLANT PV�s goal in Phase I of the DOE SBIR was to 1) develop the chemistry to grow AIGS thin films via solution processing techniques to reduce costs and 2) fabricate new device architectures with high open-circuit voltage to produce full tandem solar cells in Phase II. PLANT PV attempted to translate solution processing chemistries that were successful in producing >12% efficient Cu(In,Ga)Se2 solar cells by replacing copper compounds with silver. The main thrust of the research was to determine if it was possible to make high quality AIGS thin films using solution processing and to fully characterize the materials properties. PLANT PV developed several different types of silver compounds in an attempt to fabricate high quality thin films from solution. We found that silver compounds that were similar to the copper based system did not result in high quality thin films. PLANT PV was able to deposit AIGS thin films using a mixture of solution and physical vapor deposition processing, but these films lacked the p-type doping levels that are required to make decent solar cells. Over the course of the project PLANT PV was able to fabricate efficient CIGS solar cells (8.7%) but could not achieve equivalent performance using AIGS. During the nine-month grant PLANT PV set up a variety of thin film characterization tools (e.g. drive-level capacitance profiling) at the Molecular Foundry, a Department of Energy User Facility, that are now available to both industrial and academic researchers via the grant process. PLANT PV was also able to develop the back end processing of thin film solar cells at Lawrence Berkeley National Labs to achieve 8.7% efficient CIGS solar cells. This processing development will be applied to other types of thin film PV cells at the Lawrence Berkeley National Labs. While PLANT PV was able to study AIGS film growth and optoelectronic properties we concluded that AIGS produced using these methods would have a limited efficiency and would not be commercially feasible. PLANT PV did not apply for the Phase II of this grant.

  1. PHYSICAL REVIEW B 84, 155438 (2011) Tunable graphene band gaps from superstrate-mediated interactions

    E-Print Network [OSTI]

    Hague, Jim

    2011-01-01T23:59:59.000Z

    , and photovoltaics through the relatively simple application of polarizable materials such as SiO2 and Si3N4. DOI: 10, light-emitting diodes (LEDs), photovoltaics, heterojunctions, and photodetectors. Here, I investigate gap-enhancement effects due to inter- actions mediated through superstrates placed on graphene systems

  2. Partial frequency band gap in one-dimensional magnonic crystals M. Kostylev,1,a

    E-Print Network [OSTI]

    Adeyeye, Adekunle

    approach. It is shown that, due to the one-dimensional artificial periodicity of the medium, the gaps with the artificial spatial periodicity of the structure. In this work, by measuring the frequencies of collective on a silicon substrate using deep ultraviolet lithography with 248 nm exposure wavelength followed by a lift

  3. First-principles study of band gap engineering via oxygen vacancy doping in perovskite ABB'O? solid solutions

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

    Qi, Tingting; Curnan, Matthew T.; Kim, Seungchul; Bennett, Joseph W.; Grinberg, Ilya; Rappe, Andrew M.

    2011-12-01T23:59:59.000Z

    Oxygen vacancies in perovskite oxide solid solutions are fundamentally interesting and technologically important. However, experimental characterization of the vacancy locations and their impact on electronic structure is challenging. We have carried out first-principles calculations on two Zr-modified solid solutions, Pb(Zn1/3Nb2/3)O? and Pb(Mg1/3Nb2/3)O?, in which vacancies are present. We find that the vacancies are more likely to reside between low-valent cation-cation pairs than high-valent cation-cation pairs. Based on the analysis of our results, we formulate guidelines that can be used to predict the location of oxygen vacancies in perovskite solid solutions. Our results show that vacancies can have a significant impact on both the conduction and valence band energies, in some cases lowering the band gap by ?0.5 eV. The effects of vacancies on the electronic band structure can be understood within the framework of crystal field theory.

  4. First-principles study of band gap engineering via oxygen vacancy doping in perovskite ABB'O? solid solutions

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

    Qi, Tingting; Curnan, Matthew T.; Kim, Seungchul; Bennett, Joseph W.; Grinberg, Ilya; Rappe, Andrew M.

    2011-12-01T23:59:59.000Z

    Oxygen vacancies in perovskite oxide solid solutions are fundamentally interesting and technologically important. However, experimental characterization of the vacancy locations and their impact on electronic structure is challenging. We have carried out first-principles calculations on two Zr-modified solid solutions, Pb(Zn1/3Nb2/3)O? and Pb(Mg1/3Nb2/3)O?, in which vacancies are present. We find that the vacancies are more likely to reside between low-valent cation-cation pairs than high-valent cation-cation pairs. Based on the analysis of our results, we formulate guidelines that can be used to predict the location of oxygen vacancies in perovskite solid solutions. Our results show that vacancies can have a significant impactmore »on both the conduction and valence band energies, in some cases lowering the band gap by ?0.5 eV. The effects of vacancies on the electronic band structure can be understood within the framework of crystal field theory.« less

  5. A New Gap-Opening Mechanism in a Triple-Band Metal

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del(ANL-IN-03-032) -Less isNFebruaryOctober 2, AlgeriaQ1A Month toA New Gap-Opening

  6. Three-dimensional assemblies built up by quantum dots in size-quantization regime: Band gap shifts due to size-distribution of cadmium selenide nanoparticles

    SciTech Connect (OSTI)

    Pejova, Biljana, E-mail: biljana@pmf.ukim.mk

    2013-11-15T23:59:59.000Z

    In the present study, it is predicted that the band gap energy of a three-dimensional quantum dot assembly exhibits a red shift when the dispersion of the crystal size distribution is enlarged, even at a fixed average value thereof. The effect is manifested when the size quantization regime in individual quantum dots constituting the assembly has been entered. Under the same conditions, the sub-band gap absorption tails are characterized with large Urbach energies, which could be one or two orders of magnitude larger than the value characteristic for the non-quantized case. - Graphical abstract: Band gap shifts due to size-distribution of nanoparticles in 3D assemblies built up by quantum dots in size-quantization regime. Display Omitted - Highlights: • Optical absorption of 3D QD assemblies in size-quantization regime is modeled. • Band gap energy of the QD solid depends on the size-distribution of the nanoparticles. • QD solid samples with same ?R? exhibit band gap shift depending on size distribution. • QD size distribution leads to large Urbach energies.

  7. Significant Reduction in NiO Band Gap upon Formation of LixNi1?xO Alloys: Applications to Solar Energy Conversion

    SciTech Connect (OSTI)

    Alidoust, Nima; Toroker, Maytal; Keith, John A.; Carter, Emily A.

    2014-01-01T23:59:59.000Z

    Long-term sustainable solar energy conversion relies on identifying economical and versatile semiconductor materials with appropriate band structures for photovoltaic and photocatalytic applications (e.g., band gaps of ?1.5–2.0 eV). Nickel oxide (NiO) is an inexpensive yet highly promising candidate. Its charge-transfer character may lead to longer carrier lifetimes needed for higher efficiencies, and its conduction band edge is suitable for driving hydrogen evolution via water-splitting. However, NiO’s large band gap (?4 eV) severely limits its use in practical applications. Our first-principles quantum mechanics calculations show band gaps dramatically decrease to ?2.0 eV when NiO is alloyed with Li2O. We show that LixNi1?xO alloys (with x=0.125 and 0.25) are p-type semiconductors, contain states with no impurity levels in the gap and maintain NiO’s desirable charge-transfer character. Lastly, we show that the alloys have potential for photoelectrochemical applications, with band edges well-placed for photocatalytic hydrogen production and CO2 reduction, as well as in tandem dye-sensitized solar cells as a photocathode.

  8. Physics of band-gap formation and its evolution in the pillar-based phononic crystal structures

    SciTech Connect (OSTI)

    Pourabolghasem, Reza; Mohammadi, Saeed; Eftekhar, Ali Asghar; Adibi, Ali [School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Khelif, Abdelkrim [Institut FEMTO-ST, Université de Franche-Comté, CNRS, 32 Avenue de l'Observatoire, 25044 Besançon Cedex (France)

    2014-07-07T23:59:59.000Z

    In this paper, the interplay of Bragg scattering and local resonance is theoretically studied in a phononic crystal (PnC) structure composed of a silicon membrane with periodic tungsten pillars. The comparison of phononic band gaps (PnBGs) in three different lattice types (i.e., square, triangular, and honeycomb) with different pillar geometries shows that different PnBGs have varying degrees of dependency on the lattice symmetry based on the interplay of the local resonances and the Bragg effect. The details of this interplay is discussed. The significance of locally resonating pillars, specially in the case of tall pillars, on PnBGs is discussed and verified by examining the PnBG position and width in perturbed lattices via Monte Carlo simulations. It is shown that the PnBGs caused by the local resonance of the pillars are more resilient to the lattice perturbations than those caused by Bragg scattering.

  9. Band-gap nonlinear optical generation: The structure of internal optical field and the structural light focusing

    SciTech Connect (OSTI)

    Zaytsev, Kirill I., E-mail: kirzay@gmail.com; Katyba, Gleb M.; Yakovlev, Egor V.; Yurchenko, Stanislav O., E-mail: st.yurchenko@mail.ru [Bauman Moscow State Technical University, 2nd Baumanskaya str. 5, Moscow 105005 (Russian Federation); Gorelik, Vladimir S. [P. N. Lebedev Physics Institute of the Russian Academy of Sciences, Leninskiy Prospekt 53, Moscow 119991 (Russian Federation)

    2014-06-07T23:59:59.000Z

    A novel approach for the enhancement of nonlinear optical effects inside globular photonic crystals (PCs) is proposed and systematically studied via numerical simulations. The enhanced optical harmonic generation is associated with two- and three-dimensional PC pumping with the wavelength corresponding to different PC band-gaps. The interactions between light and the PC are numerically simulated using the finite-difference time-domain technique for solving the Maxwell's equations. Both empty and infiltrated two-dimensional PC structures are considered. A significant enhancement of harmonic generation is predicted owing to the highly efficient PC pumping based on the structural light focusing effect inside the PC structure. It is shown that a highly efficient harmonic generation could be attained for both the empty and infiltrated two- and three-dimensional PCs. We are demonstrating the ability for two times enhancement of the parametric decay efficiency, one order enhancement of the second harmonic generation, and two order enhancement of the third harmonic generation in PC structures in comparison to the nonlinear generations in appropriate homogenous media. Obviously, the nonlinear processes should be allowed by the molecular symmetry. The criteria of the nonlinear process efficiency are specified and calculated as a function of pumping wavelength position towards the PC globule diameter. Obtained criterion curves exhibit oscillating characteristics, which indicates that the highly efficient generation corresponds to the various PC band-gap pumping. The highest efficiency of nonlinear conversions could be reached for PC pumping with femtosecond optical pulses; thus, the local peak intensity would be maximized. Possible applications of the observed phenomenon are also discussed.

  10. Gallium arsenide-based ternary compounds and multi-band-gap solar cell research. Annual subcontract report, 15 April 1988--14 June 1990

    SciTech Connect (OSTI)

    Vernon, S. [Spire Corp., Bedford, MA (United States)

    1993-02-01T23:59:59.000Z

    Aim of this contract is the achievement of a high-efficiency, low-cost solar cell. The basic approach to the problem is centered upon the heteroepitaxial growth of a III-V compound material onto a single-crystal silicon wafer. The growth technique employed is metalorganic chemical vapor deposition. The silicon wafer may serve as a mechanical substrate and ohmic contact for a single-junction device, or may contain a p-n junction of its own and form the bottom cell of a two junction tandem solar cell structure. The III-V material for the single-junction case is GaAs and for the two-junction case is either GaAlAs or GaAsP, either material having the proper composition to yield a band gap of approximately 1.7 eV. Results achieved in this contract include the following: (1) a 17.6% efficient GaAs-on-Si solar cell; (2) an 18.5% efficient GaAs-on-Si concentrator solar cell at 400 suns; (3) a 24.8% efficient GaAs-on-GaAs solar cell; (4) a 28.7% efficient GaAs-on-GaAs concentrator solar cell at 200 suns; (5) measurement of the effects of dislocation density and emitter doping on GaAs cells; and (6) improvements in the growth process to achieve reproducible thin AlGaAs window layers with low recombination velocities and environmental stability.

  11. On the sub-band gap optical absorption in heat treated cadmium sulphide thin film deposited on glass by chemical bath deposition technique

    SciTech Connect (OSTI)

    Chattopadhyay, P.; Karim, B.; Guha Roy, S. [Department of Electronic Science, University of Calcutta, 92, A.P.C. Road, Kolkata 700009 (India)

    2013-12-28T23:59:59.000Z

    The sub-band gap optical absorption in chemical bath deposited cadmium sulphide thin films annealed at different temperatures has been critically analyzed with special reference to Urbach relation. It has been found that the absorption co-efficient of the material in the sub-band gap region is nearly constant up to a certain critical value of the photon energy. However, as the photon energy exceeds the critical value, the absorption coefficient increases exponentially indicating the dominance of Urbach rule. The absorption coefficients in the constant absorption region and the Urbach region have been found to be sensitive to annealing temperature. A critical examination of the temperature dependence of the absorption coefficient indicates two different kinds of optical transitions to be operative in the sub-band gap region. After a careful analyses of SEM images, energy dispersive x-ray spectra, and the dc current-voltage characteristics, we conclude that the absorption spectra in the sub-band gap domain is possibly associated with optical transition processes involving deep levels and the grain boundary states of the material.

  12. Size-dependent shifts of the Néel temperature and optical band-gap in NiO nanoparticles

    SciTech Connect (OSTI)

    Thota, Subhash, E-mail: mseehra@wvu.edu, E-mail: subhasht@iitg.ac.in [Department of Physics, Indian Institute of Technology, Guwahati, Assam 781039 (India); Shim, J. H.; Seehra, M. S., E-mail: mseehra@wvu.edu, E-mail: subhasht@iitg.ac.in [Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506 (United States)

    2013-12-07T23:59:59.000Z

    Bulk NiO is a well-known antiferromagnet with Neel temperature T{sub N}(?)?=?524?K and an optical band-gap E{sub g}?=?4.3?eV. With decrease in particle size D from 40?nm to 4?nm of NiO, systematic changes of T{sub N} and E{sub g} are observed and discussed here. From magnetic measurements, the changes in T{sub N} with D are found to fit finite-size scaling equation T{sub N}(D)?=?T{sub N}(?) [1 ? (?{sub o}/D){sup ?}] with ??=?3.2?±?0.5 and ?{sub o}?=?3.2?±?0.2?nm, in good agreement with the predictions for a Heisenberg system. The observed blue shifts of E{sub g} with decrease in D reaching E{sub g}?=?5.12?eV for D???4?nm are likely due to quantum confinement and non-stoichiometry.

  13. Toward Photochemical Water Splitting Using Band-Gap-Narrowed Semiconductors and Transition-Metal Based Molecular Catalysts

    SciTech Connect (OSTI)

    Muckerman,J.T.; Rodriguez, J.A.; Fujita, E.

    2009-06-07T23:59:59.000Z

    We are carrying out coordinated theoretical and experimental studies of toward photochemical water splitting using band-gap-narrowed semiconductors (BGNSCs) with attached multi-electron molecular water oxidation and hydrogen production catalysts. We focus on the coupling between the materials properties and the H{sub 2}O redox chemistry, with an emphasis on attaining a fundamental understanding of the individual elementary steps in the following four processes: (1) Light-harvesting and charge-separation of stable oxide or oxide-derived semiconductors for solar-driven water splitting, including the discovery and characterization of the behavior of such materials at the aqueous interface; (2) The catalysis of the four-electron water oxidation by dinuclear hydroxo transition-metal complexes with quinonoid ligands, and the rational search for improved catalysts; (3) Transfer of the design principles learned from the elucidation of the DuBois-type hydrogenase model catalysts in acetonitrile to the rational design of two-electron hydrogen production catalysts for aqueous solution; (4) Combining these three elements to examine the function of oxidation catalysts on BGNSC photoanode surfaces and hydrogen production catalysts on cathode surfaces at the aqueous interface to understand the challenges to the efficient coupling of the materials functions.

  14. Electric-field-dependent electroreflectance spectra of visible-band-gap (InAlGa)P quantum-well structures

    SciTech Connect (OSTI)

    Fritz, I.J.; Blum, O.; Schneider, R.P. Jr.; Howard, A.J.; Follstaedt, D.M. (Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States))

    1994-04-04T23:59:59.000Z

    We present results from the first studies of electric-field effects on optical transitions in visible-band-gap InGaP/InAlGaP multiple-quantum-well (MQW) structures. These structures, grown at 775 [degree]C by metalorganic vapor phase epitaxy on (100) GaAs substrates misoriented 6[degree] towards P(111)[r angle][l angle]111[r angle]A, consist of nominally undoped MQWs surrounded by doped In[sub 0.49]Al[sub 0.51]P cladding layers to form [ital p]-[ital i]-[ital n] diodes. The Stark shifts of various allowed and forbidden quantum-well transitions were observed in bias-dependent electroreflectance spectra of In[sub 0.49]Ga[sub 0.51]P/In[sub 0.49](Al[sub 0.5]Ga[sub 0.5])[sub 0.51]P MQW samples with 10-nm-thick layers. We find the magnitude of these shifts to depend on the details of the Mg doping profile, confirming the importance of Mg diffusion and unintentional background doping in these materials. Our results show that (InAlGa)P materials are promising for visible-wavelength electro-optic modulator applications.

  15. Gallium arsenide-based ternary compounds and multi-band-gap solar cell research. Final subcontract report, 1 April 1988--31 March 1990

    SciTech Connect (OSTI)

    Vernon, S. [Spire Corp., Bedford, MA (United States)

    1993-07-01T23:59:59.000Z

    This report describes work to achieve a high-efficiency, low-cost solar cell. The basic approach to the problem is centered upon the heteroepitaxial growth of a III-V compound material onto a single-crystal silicon wafer. The growth technique employed throughout this work is metal-organic chemical vapor deposition. The silicon wafer may serve as a mechanical substrate and ohmic contact for a single-junction device, or it may contain a p-n junction of its own and form the bottom cell of a two-junction tandem solar cell structure. The III-V material for the single-junction case is GaAs, and for the two-junction case it is either GaAlAs or GaAsP, either material having the proper composition to yield a band gap of approximately 1.7 eV. Results achieved in this contract include (1) a 17.6%-efficient GaAs-on-Si solar cell; (2) an 18.5%-efficient GaAs-on-Si concentrator solar cell at 400 suns; (3) a 24.8%-efficient GaAs-on-GaAs solar cell; (4) a 28.7%-efficient GaAs-on-GaAs concentrator solar cell at 200 suns; (5) the measurement of the effects of dislocation density and emitter doping on GaAs cells; and (6) improvements in the growth process to achieve reproducible thin AlGaAs window layers with low recombination velocities and environmental stability.

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

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

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

    2011-08-01T23:59:59.000Z

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

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

    SciTech Connect (OSTI)

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

    2011-08-01T23:59:59.000Z

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

  18. Band gap engineering of In{sub 2}O{sub 3} by alloying with Tl{sub 2}O{sub 3}

    SciTech Connect (OSTI)

    Scanlon, David O., E-mail: d.scanlon@ucl.ac.uk [Kathleen Lonsdale Materials Chemistry, Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ (United Kingdom); Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom); Regoutz, Anna; Egdell, Russell G. [Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR (United Kingdom)] [Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR (United Kingdom); Morgan, David J. [Cardiff Catalysis Institute (CCI), School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT (United Kingdom)] [Cardiff Catalysis Institute (CCI), School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT (United Kingdom); Watson, Graeme W. [School of Chemistry and CRANN, Trinity College Dublin, Dublin 2 (Ireland)] [School of Chemistry and CRANN, Trinity College Dublin, Dublin 2 (Ireland)

    2013-12-23T23:59:59.000Z

    Efficient modulation of the bandgap of In{sub 2}O{sub 3} will open up a route to improved electronic properties. We demonstrate using ab initio calculations that Tl incorporation into In{sub 2}O{sub 3} reduces the band gap and confirm that narrowing of the gap is observed by X-ray photoemission spectroscopy on ceramic surfaces. Incorporation of Tl does not break the symmetry of the allowed optical transitions, meaning that the doped thin films should retain optical transparency in the visible region, in combination with a lowering of the conduction band effective mass. We propose that Tl-doping may be an efficient way to increase the dopability and carrier mobility of In{sub 2}O{sub 3}.

  19. Structure and red shift of optical band gap in CdO–ZnO nanocomposite synthesized by the sol gel method

    SciTech Connect (OSTI)

    Mosquera, Edgar, E-mail: edemova@ing.uchile.cl [Laboratorio de Materiales a Nanoescala, Departamento de Ciencia de los Materiales, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Av. Tupper 2069, Santiago (Chile); Pozo, Ignacio del, E-mail: ignacio.dpf@gmail.com [Facultad de Ciencias Naturales, Matemáticas y del Medio Ambiente, Universidad Tecnológica Metropolitana, Av. José Pedro Alessandri 1242, Santiago (Chile); Morel, Mauricio, E-mail: mmorel@ing.uchile.cl [Laboratorio de Materiales a Nanoescala, Departamento de Ciencia de los Materiales, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Av. Tupper 2069, Santiago (Chile)

    2013-10-15T23:59:59.000Z

    The structure and the optical band gap of CdO–ZnO nanocomposites were studied. Characterization using X-ray diffraction (XRD), transmission electron microscopy (TEM) and diffuse reflectance spectroscopy (DRS) analysis confirms that CdO phase is present in the nanocomposites. TEM analysis confirms the formation of spheroidal nanoparticles and nanorods. The particle size was calculated from Debey–Sherrer?s formula and corroborated by TEM images. FTIR spectroscopy shows residual organic materials (aromatic/Olefinic carbon) from nanocomposites surface. CdO content was modified in the nanocomposites in function of polyvinylalcohol (PVA) added. The optical band gap is found to be red shift from 3.21 eV to 3.11 eV with the increase of CdO content. Photoluminescence (PL) measurements reveal the existence of defects in the synthesized CdO–ZnO nanocomposites. - Graphical abstract: Optical properties of ZnO, CdO and ZnO/CdO nanoparticles. Display Omitted - Highlights: • TEM analysis confirms the presence of spherical nanoparticles and nanorods. • The CdO phase is present in the nanocomposites. • The band gap of the CdO–ZnO nanocomposites is slightly red shift with CdO content. • PL emission of CdO–ZnO nanocomposite are associated to structural defects.

  20. Direct band gap optical emission from compressively strained Ge films grown on relaxed Si{sub 0.5}Ge{sub 0.5} substrate

    SciTech Connect (OSTI)

    Aluguri, R.; Manna, S.; Ray, S. K. [Department of Physics and Meteorology, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India)] [Department of Physics and Meteorology, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India)

    2013-10-14T23:59:59.000Z

    Compressively strained Ge films have been grown on relaxed Si{sub 0.5}Ge{sub 0.5} virtual substrate in ultra high vacuum using molecular beam epitaxy. Structural characterization has shown that the Ge films are compressively strained with partial strain relaxation in a film thicker than 3.0 nm, due to onset of island nucleation. Photoluminescence spectra exhibit the splitting of degenerate Ge valence band into heavy hole and light hole bands with a broad direct band gap emission peak around 0.81 eV. Temperature and excitation power dependent emission characteristics have been studied to investigate the mechanism of luminescence quenching at high temperatures and the role of non-radiative recombination centers.

  1. Design, Modeling and Numerical Analysis of Microwave and Optical Devices: The Multi-band Patch Antenna, Ultra Wideband Ring Filter and Plasmonic Waveguide Coupler

    E-Print Network [OSTI]

    Liu, Ya-Chi

    2014-01-14T23:59:59.000Z

    In this dissertation, three devices are studied and devised for the applications in microwave and optical communication: (1) Multiband Patch Antenna, (2) Ultra-Wideband Band Pass Ring Filter and (3) Plasmonic Waveguide Coupler with High Coupling...

  2. Band-Gap Engineering of Zinc Oxide Colloids via Lattice Substitution with Sulfur Leading to Materials with Advanced Properties for

    E-Print Network [OSTI]

    Nabben, Reinhard

    gap semiconductors like III/V compounds, for instance, gallium nitride (GaN),2 or II/VI compounds bandgap of 3.37 eV at room temperature.7 Thus, one of its most elemental functions is the absorption

  3. PHYSICAL REVIEW B 85, 155101 (2012) Electronic properties of layered multicomponent wide-band-gap oxides: A combinatorial approach

    E-Print Network [OSTI]

    Medvedeva, Julia E.

    devices including solar cells, smart windows, and flat panel displays, and they also find application as heating, antistatic, and optical coatings (for select reviews, see Refs. 1­7). Multicomponent TCOs

  4. Optical and structural study of GaN nanowires grown by catalyst-free molecular beam epitaxy. II. Sub-band-gap luminescence and electron irradiation effects

    SciTech Connect (OSTI)

    Robins, Lawrence H.; Bertness, Kris A.; Barker, Joy M.; Sanford, Norman A.; Schlager, John B. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); National Institute of Standards and Technology, Boulder, Colorado 80305 (United States)

    2007-06-01T23:59:59.000Z

    GaN nanowires with diameters of 50-250 nm, grown by catalyst-free molecular beam epitaxy, were characterized by photoluminescence (PL) and cathodoluminescence (CL) spectroscopy at temperatures from 3 to 297 K. Both as-grown samples and dispersions of the nanowires onto other substrates were examined. The properties of the near-band-edge PL and CL spectra were discussed in Part I of this study by [Robins et al. [L. H. Robins, K. A. Bertness, J. M. Barker, N. A. Sanford, and J. B. Schlager, J. Appl. Phys. 101,113505 (2007)]. Spectral features below the band gap, and the effect of extended electron irradiation on the CL, are discussed in Part II. The observed sub-band-gap PL and CL peaks are identified as phonon replicas of the free-exciton transitions, or excitons bound to structural defects or surface states. The defect-related peaks in the nanowires are correlated with luminescence lines previously reported in GaN films, denoted the Y lines [M. A. Reshchikov and H. Morkoc, J. Appl. Phys. 97, 061301 (2005)]. The CL was partially quenched by electron beam irradiation for an extended time; the quenching was stronger for the free and shallow-donor-bound exciton peaks than for the defect-related peaks. The quenching appeared to saturate at high irradiation dose (with final intensity {approx_equal}30% of initial intensity) and was reversible on thermal cycling to room temperature. The electron irradiation-induced quenching of the CL is ascribed to charge injection and trapping phenomena.

  5. Modeling the effect of native and laser-induced states on the dielectric breakdown of wide band gap optical materials by multiple subpicosecond laser pulses

    SciTech Connect (OSTI)

    Emmert, Luke A.; Mero, Mark; Rudolph, Wolfgang [Department of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico 87131 (United States)

    2010-08-15T23:59:59.000Z

    A model for the multiple-pulse laser-induced breakdown behavior of dielectrics is presented. It is based on a critical conduction band (CB) electron density leading to dielectric breakdown. The evolution of the CB electron density during the pulse train is calculated using rate equations involving transitions between band and mid-gap states (native and laser-induced). Using realistic estimations for the trap density and ionization cross-section, the model is able to reproduce the experimentally observed drop in the multiple-pulse damage threshold relative to the single-pulse value, as long as the CB electron density is controlled primarily by avalanche ionization seeded by multiphoton ionization of the traps and the valence band. The model shows that at long pulse duration, the breakdown threshold becomes more sensitive to presence of traps close (within one photon energy) to the CB. The effect of native and laser-induced defects can be distinguished by their saturation behavior. Finally, measurements of the multiple-pulse damage threshold of hafnium oxide films are used to illustrate the application of the model.

  6. Solar Energy Materials & Solar Cells 91 (2007) 15991610 Improving solar cell efficiency using photonic band-gap materials

    E-Print Network [OSTI]

    Dowling, Jonathan P.

    Solar Energy Materials & Solar Cells 91 (2007) 1599­1610 Improving solar cell efficiency using) solar energy conversion systems (or solar cells) are the most widely used power systems. However and reliable solar-cell devices is presented. We show that due their ability to modify the spectral and angular

  7. PHYSICAL REVIEW B 84, 035315 (2011) Theoretical analysis of the crystal structure, band-gap energy, polarization, and piezoelectric

    E-Print Network [OSTI]

    Alpay, S. Pamir

    2011-01-01T23:59:59.000Z

    have already been incorporated in flat panel displays and solar cells as transparent electrodesO can be tailored by alloying ZnO with BeO for applications such as electrodes in flat panel displays and solar cells, blue and ultraviolet (UV) light emitting devices, and highly sensitive UV detectors. We

  8. Exact-exchange-based quasiparticle energy calculations for the band gap, effective masses, and deformation potentials of ScN

    E-Print Network [OSTI]

    of less than 2% to cubic gallium nitride GaN . This makes ScN structurally compatible with the group devices. Alloying ScN with GaN Refs. 9­12 might provide a viable alternative to InGaN alloys for use tunneling spectroscopy and optical-absorption mea- surements, Al-Brithen et al.18 were able to reduce

  9. Identifying topological-band insulator transitions in silicene and other 2D gapped Dirac materials by means of Rényi-Wehrl entropy

    E-Print Network [OSTI]

    M. Calixto; E. Romera

    2015-02-11T23:59:59.000Z

    We propose a new method to identify transitions from a topological insulator to a band insulator in silicene (the silicon equivalent of graphene) in the presence of perpendicular magnetic and electric fields, by using the R\\'enyi-Wehrl entropy of the quantum state in phase space. Electron-hole entropies display an inversion/crossing behavior at the charge neutrality point for any Landau level, and the combined entropy of particles plus holes turns out to be maximum at this critical point. The result is interpreted in terms of delocalization of the quantum state in phase space. The entropic description presented in this work will be valid in general 2D gapped Dirac materials, with a strong intrinsic spin-orbit interaction, isoestructural with silicene.

  10. Resonant charge transfer of hydrogen Rydberg atoms incident at a Cu(100) projected band-gap surface

    E-Print Network [OSTI]

    Gibbard, J A; Kohlhoff, M; Rennick, C J; So, E; Ford, M; Softley, T P

    2015-01-01T23:59:59.000Z

    The charge transfer (ionization) of hydrogen Rydberg atoms (principal quantum number $n=25-34$) incident at a Cu(100) surface is investigated. Unlike fully metallic surfaces, where the Rydberg electron energy is degenerate with the conduction band of the metal, the Cu(100) surface has a projected bandgap at these energies, and only discrete image states are available through which charge transfer can take place. Resonant enhancement of charge transfer is observed at hydrogen principal quantum numbers for which the Rydberg energy matches the energy of one of the image states. The integrated surface ionization signals show clear periodicity as the energies of states with increasing $n$ come in and out of resonance with the image states. The velocity dependence of the surface ionization dynamics is also investigated. Decreased velocity of the incident H atom leads to a greater mean distance of ionization and a lower field required to extract the ion. The surface-ionization profiles (signal versus applied field) ...

  11. Intermediate-band photosensitive device with quantum dots having tunneling barrier embedded in organic matrix

    DOE Patents [OSTI]

    Forrest, Stephen R. (Ann Arbor, MI)

    2008-08-19T23:59:59.000Z

    A plurality of quantum dots each have a shell. The quantum dots are embedded in an organic matrix. At least the quantum dots and the organic matrix are photoconductive semiconductors. The shell of each quantum dot is arranged as a tunneling barrier to require a charge carrier (an electron or a hole) at a base of the tunneling barrier in the organic matrix to perform quantum mechanical tunneling to reach the respective quantum dot. A first quantum state in each quantum dot is between a lowest unoccupied molecular orbital (LUMO) and a highest occupied molecular orbital (HOMO) of the organic matrix. Wave functions of the first quantum state of the plurality of quantum dots may overlap to form an intermediate band.

  12. Intermediate-band photosensitive device with quantum dots embedded in energy fence barrier

    DOE Patents [OSTI]

    Forrest, Stephen R. (Ann Arbor, MI); Wei, Guodan (Ann Arbor, MI)

    2010-07-06T23:59:59.000Z

    A plurality of layers of a first semiconductor material and a plurality of dots-in-a-fence barriers disposed in a stack between a first electrode and a second electrode. Each dots-in-a-fence barrier consists essentially of a plurality of quantum dots of a second semiconductor material embedded between and in direct contact with two layers of a third semiconductor material. Wave functions of the quantum dots overlap as at least one intermediate band. The layers of the third semiconductor material are arranged as tunneling barriers to require a first electron and/or a first hole in a layer of the first material to perform quantum mechanical tunneling to reach the second material within a respective quantum dot, and to require a second electron and/or a second hole in a layer of the first semiconductor material to perform quantum mechanical tunneling to reach another layer of the first semiconductor material.

  13. Performance of an MPI-only semiconductor device simulator on a quad socket/quad core InfiniBand platform.

    SciTech Connect (OSTI)

    Shadid, John Nicolas; Lin, Paul Tinphone

    2009-01-01T23:59:59.000Z

    This preliminary study considers the scaling and performance of a finite element (FE) semiconductor device simulator on a capacity cluster with 272 compute nodes based on a homogeneous multicore node architecture utilizing 16 cores. The inter-node communication backbone for this Tri-Lab Linux Capacity Cluster (TLCC) machine is comprised of an InfiniBand interconnect. The nonuniform memory access (NUMA) nodes consist of 2.2 GHz quad socket/quad core AMD Opteron processors. The performance results for this study are obtained with a FE semiconductor device simulation code (Charon) that is based on a fully-coupled Newton-Krylov solver with domain decomposition and multilevel preconditioners. Scaling and multicore performance results are presented for large-scale problems of 100+ million unknowns on up to 4096 cores. A parallel scaling comparison is also presented with the Cray XT3/4 Red Storm capability platform. The results indicate that an MPI-only programming model for utilizing the multicore nodes is reasonably efficient on all 16 cores per compute node. However, the results also indicated that the multilevel preconditioner, which is critical for large-scale capability type simulations, scales better on the Red Storm machine than the TLCC machine.

  14. Hybrid density functional calculations of the band gap of GaxIn1-xN Xifan Wu,1 Eric J. Walter,2 Andrew M. Rappe,3 Roberto Car,1 and Annabella Selloni1

    E-Print Network [OSTI]

    Rappe, Andrew M.

    Hybrid density functional calculations of the band gap of GaxIn1-xN Xifan Wu,1 Eric J. Walter,2 Andrew M. Rappe,3 Roberto Car,1 and Annabella Selloni1 1Chemistry Department, Princeton University Recent theoretical work has provided evidence that hybrid functionals, which include a fraction of exact

  15. VOLUME 84, NUMBER 19 P H Y S I C A L R E V I E W L E T T E R S 8 MAY 2000 Theory and Experiments on Elastic Band Gaps

    E-Print Network [OSTI]

    Investigaciones Científicas (CSIC), Serrano 144, 28006 Madrid, Spain 2 Ames Laboratory, Iowa State University, Ames, Iowa 50011 3 Instituto de Acústica, CSIC, Serrano 144, 28006 Madrid, Spain 4 Instituto de Física Aplicada, CSIC, Serrano 144, 28006 Madrid, Spain (Received 26 February 1999) We study elastic band gaps

  16. The Study of Energy Band Gap of In{sub x}Al{sub y}Ga{sub 1-x-y}N Quaternary Alloys using UV-VIS Spectroscopy

    SciTech Connect (OSTI)

    Raof, N. H. Abd.; Ng, S. S.; Hassan, H. Abu; Hassan, Z. [Nano-Optoelectronics Research Laboratory, School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia)

    2009-06-01T23:59:59.000Z

    Quaternary In{sub x}Al{sub y}Ga{sub 1-x-y}N alloys with indium (In) mole fraction x ranging from 0.01 to 0.10 and constant aluminum (Al) mole fraction y = 0.06, were grown by molecular beam epitaxy. The energy band gaps of InAlGaN alloys were investigated using UV-VIS spectroscopy under room temperature. The energy band gap decreases with increasing In composition from 0.01 to 0.08. This trend is expected since the incorporation of In lowers the energy band gap of Al{sub 0.06}Ga{sub 0.94}N(3.72 eV). However, for InAlGaN with In composition of 0.1, the band gap shows a sudden increase in energy. This is probably due to local alloy compositional fluctuations in the epilayer, contributed by incomplete substitutions of Ga atoms by the In atoms, thus retaining a much richer GaN structure. Finally, we investigate the bowing parameter appears also to be very sensitive on In content. We obtained b 50.08 for quaternary InAlGaN alloys.

  17. Biology is curved, soft and elastic; silicon wafers are not. Semiconductor technologies that can bridge this gap in form and mechanics will create new opportunities in devices that adopt

    E-Print Network [OSTI]

    Reisslein, Martin

    ABSTRACT Biology is curved, soft and elastic; silicon wafers are not. Semiconductor technologies that can bridge this gap in form and mechanics will create new opportunities in devices that adopt

  18. Band-Gap Reduction and Dopant Interaction in Epitaxial La,Cr Co-doped SrTiO3 Thin Films

    SciTech Connect (OSTI)

    Comes, Ryan B.; Sushko, Petr; Heald, Steve M.; Colby, Robert J.; Bowden, Mark E.; Chambers, Scott A.

    2014-12-03T23:59:59.000Z

    We show that by co-doping SrTiO3 (STO) epitaxial thin films with equal amounts of La and Cr it is possible to produce films with an optical band gap ~0.9 eV lower than that of undoped STO. Sr1-xLaxTi1-xCrxO3 thin films were deposited by molecular beam epitaxy and characterized using x-ray photoelectron spectroscopy and x-ray absorption near-edge spectroscopy to show that the Cr dopants are almost exclusively in the Cr3+ oxidation state. Extended x-ray absorption fine structure measurements and theoretical modeling suggest that it is thermodynamically preferred for La and Cr dopants to occupy nearest neighbor A- and B-sites in the lattice. Transport measurements show that the material exhibits variable-range hopping conductivity with high resistivity. These results create new opportunities for the use of doped STO films in photovoltaic and photocatalytic applications.

  19. High Efficiency Narrow Gap and Tandem Junction Devices: Final Technical Report, 1 May 2002--31 October 2004

    SciTech Connect (OSTI)

    Madan, A

    2005-03-01T23:59:59.000Z

    The work described in this report uses a modified pulsed plasma-enhanced chemical vapor deposition (PECVD) technique that has been successfully developed to fabricate state-of-the-art nc-Si materials and devices. Specifically, we have achieved the following benchmarks: nc SiH device with an efficiency of 8% achieved at a deposition rate of {approx}1 A/s; nc SiH device with an efficiency of 7% achieved at a deposition rate of {approx}5 A/s; large-area technology developed using pulsed PECVD with uniformity of +/-5% over 25 cm x 35 cm; devices have been fabricated in the large-area system (part of Phase 3); an innovative stable four-terminal (4-T) tandem-junction device of h> 9% fabricated. (Note that the 4-T device was fabricated with existing technology base and with further development can reach stabilized h of 12%); and with improvement in Voc {approx} 650 mV, from the current value of 480 mV can lead to stable 4-T device with h>16%. Toward this objective, modified pulsed PECVD was developed where layer- by-layer modification of nc-SiH has been achieved. (Note that due to budget cuts at NREL, this project was curtailed by about one year.)

  20. Sealing device

    SciTech Connect (OSTI)

    Garcia-Crespo, Andres Jose

    2013-12-10T23:59:59.000Z

    A sealing device for sealing a gap between a dovetail of a bucket assembly and a rotor wheel is disclosed. The sealing device includes a cover plate configured to cover the gap and a retention member protruding from the cover plate and configured to engage the dovetail. The sealing device provides a seal against the gap when the bucket assemply is subjected to a centrifugal force.

  1. Wide band gap semiconductor templates

    DOE Patents [OSTI]

    Arendt, Paul N. (Los Alamos, NM); Stan, Liliana (Los Alamos, NM); Jia, Quanxi (Los Alamos, NM); DePaula, Raymond F. (Santa Fe, NM); Usov, Igor O. (Los Alamos, NM)

    2010-12-14T23:59:59.000Z

    The present invention relates to a thin film structure based on an epitaxial (111)-oriented rare earth-Group IVB oxide on the cubic (001) MgO terminated surface and the ion-beam-assisted deposition ("IBAD") techniques that are amendable to be over coated by semiconductors with hexagonal crystal structures. The IBAD magnesium oxide ("MgO") technology, in conjunction with certain template materials, is used to fabricate the desired thin film array. Similarly, IBAD MgO with appropriate template layers can be used for semiconductors with cubic type crystal structures.

  2. Theoretical study of influencing factors on the dispersion of bulk band-gap edges and the surface states in topological insulators Bi{sub 2}Te{sub 3} and Bi{sub 2}Se{sub 3}

    SciTech Connect (OSTI)

    Rusinov, I. P., E-mail: rusinovip@gmail.com; Nechaev, I. A. [Tomsk State University (Russian Federation); Chulkov, E. V. [Donostia International Physics Center (DIPC) (Spain)

    2013-06-15T23:59:59.000Z

    The dispersion of the band-gap edge states in bulk topological insulators Bi{sub 2}Te{sub 3} and Bi{sub 2}Se{sub 3} is considered within density functional theory. The dependences of this dispersion both on the approximation used for an exchange-correlation functional at fixed unit cell parameters and atomic positions and on these parameters and positions that are obtained upon structural relaxation performed using a certain approximated functional are analyzed. The relative position of the Dirac point of topologically protected surface states and the valence band maximum in the surface electronic structure of the topological insulators is discussed.

  3. Band gap modification and ferroelectric properties of Bi{sub 0.5}(Na,K){sub 0.5}TiO{sub 3}-based by Li substitution

    SciTech Connect (OSTI)

    Quan, Ngo Duc [Department of General Physics, School of Engineering Physics, Ha Noi University of Science and Technology, 1 Dai Co Viet road, Ha Noi (Viet Nam) [Department of General Physics, School of Engineering Physics, Ha Noi University of Science and Technology, 1 Dai Co Viet road, Ha Noi (Viet Nam); International Training Institute for Materials Science, Hanoi University of Science and Technology, 1 Dai Co Viet road, Hanoi (Viet Nam); Hung, Vu Ngoc [International Training Institute for Materials Science, Hanoi University of Science and Technology, 1 Dai Co Viet road, Hanoi (Viet Nam)] [International Training Institute for Materials Science, Hanoi University of Science and Technology, 1 Dai Co Viet road, Hanoi (Viet Nam); Quyet, Nguyen Van [Hanautech Co., Ltd., 832, Tamnip-dong, Yuseong-gu, Daejeon (Korea, Republic of)] [Hanautech Co., Ltd., 832, Tamnip-dong, Yuseong-gu, Daejeon (Korea, Republic of); Chung, Hoang Vu [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet street, Hanoi (Viet Nam)] [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet street, Hanoi (Viet Nam); Dung, Dang Duc, E-mail: dung.dangduc@hust.edu.vn [Department of General Physics, School of Engineering Physics, Ha Noi University of Science and Technology, 1 Dai Co Viet road, Ha Noi (Viet Nam)

    2014-01-15T23:59:59.000Z

    We report on the reduction of band gap in Bi{sub 0.5}(Na{sub 0.82-x}Li{sub x}K{sub 0.18}){sub 0.5}(Ti{sub 0.95}Sn{sub 0.05})O{sub 3} from 2.99 eV to 2.84 eV due to the substitutions of Li{sup +} ions to Na{sup +} sites. In addition, the lithium substitution samples exhibit an increasing of the maximal polarizations from 21.8 to 25.7 ?C/cm{sup 2}. The polarization enhancement of ferroelectric and reduction of the band gaps are strongly related to the Li substitution concentration as evaluated via the electronegative between A-site and oxygen and tolerance factor. The results are promising for photovoltaic and photocatalytic applications.

  4. Towards Direct-Gap Silicon Phases by the Inverse Band Structure Design Approach H. J. Xiang,1,2,* Bing Huang,2

    E-Print Network [OSTI]

    Gong, Xingao

    phase with quasidirect gaps of 1.55 eV, which is a promising candidate for making thin-film solar cells have also been based on diamond Si in monocrystalline or large-grained polycrystalline form [1 gap of 1.55 eV. We suggest that these new Si phases could be used in thin-film solar cells

  5. Structural phase transition, narrow band gap, and room-temperature ferromagnetism in [KNbO{sub 3}]{sub 1?x}[BaNi{sub 1/2}Nb{sub 1/2}O{sub 3??}]{sub x} ferroelectrics

    SciTech Connect (OSTI)

    Zhou, Wenliang; Yang, Pingxiong, E-mail: pxyang@ee.ecnu.edu.cn; Chu, Junhao [Key Laboratory of Polar Materials and Devices, Ministry of Education, Department of Electronic Engineering, East China Normal University, Shanghai 200241 (China); Deng, Hongmei [Instrumental Analysis and Research Center, Institute of Materials, Shanghai University, 99 Shangda Road, Shanghai 200444 (China)

    2014-09-15T23:59:59.000Z

    Structural phase transition, narrow band gap (E{sub g}), and room-temperature ferromagnetism (RTFM) have been observed in the [KNbO{sub 3}]{sub 1?x}[BaNi{sub 1/2}Nb{sub 1/2}O{sub 3??}]{sub x} (KBNNO) ceramics. All the samples have single phase perovskite structure, but exhibit a gradual transition behaviour from the orthorhombic to a cubic structure with the increase of x. Raman spectroscopy analysis not only corroborates this doping-induced change in normal structure but also shows the local crystal symmetry for x ? 0.1 compositions to deviate from the idealized cubic perovskite structure. A possible mechanism for the observed specific changes in lattice structure is discussed. Moreover, it is noted that KBNNO with compositions x?=?0.1–0.3 have quite narrow E{sub g} of below 1.5?eV, much smaller than the 3.2?eV band gap of parent KNbO{sub 3} (KNO), which is due to the increasing Ni 3d electronic states within the gap of KNO. Furthermore, the KBNNO materials present RTFM near a tetragonal to cubic phase boundary. With increasing x from 0 to 0.3, the magnetism of the samples develops from diamagnetism to ferromagnetism and paramagnetism, originating from the ferromagnetic–antiferromagnetic competition. These results are helpful in the deeper understanding of phase transitions, band gap tunability, and magnetism variations in perovskite oxides and show the potential role, such materials can play, in perovskite solar cells and multiferroic applications.

  6. Band structure engineering for solar energy applications: ZnO1-xSex films and devices

    E-Print Network [OSTI]

    Mayer, Marie Annette

    2012-01-01T23:59:59.000Z

    a device, the short circuit current is increased through theI SC is the short circuit current of the system; 1.23 V is67% vs. 27%), with a short circuit current nearly 10 times

  7. Real-structure effects: Band gaps of Mg_xZn_{1-x}O, Cd_xZn_{1-x}O, and n-type ZnO from ab-initio calculations

    SciTech Connect (OSTI)

    Schleife, A; Bechstedt, F

    2012-02-15T23:59:59.000Z

    Many-body perturbation theory is applied to compute the quasiparticle electronic structures and the optical-absorption spectra (including excitonic effects) for several transparent conducting oxides. We discuss HSE+G{sub 0}W{sub 0} results for band structures, fundamental band gaps, and effective electron masses of MgO, ZnO, CdO, SnO{sub 2}, SnO, In{sub 2}O{sub 3}, and SiO{sub 2}. The Bethe-Salpeter equation is solved to account for excitonic effects in the calculation of the frequency-dependent absorption coefficients. We show that the HSE+G{sub 0}W{sub 0} approach and the solution of the Bethe-Salpeter equation are very well-suited to describe the electronic structure and the optical properties of various transparent conducting oxides in good agreement with experiment.

  8. Spark gap with low breakdown voltage jitter

    DOE Patents [OSTI]

    Rohwein, Gerald J. (Albuquerque, NM); Roose, Lars D. (Albuquerque, NM)

    1996-01-01T23:59:59.000Z

    Novel spark gap devices and electrodes are disclosed. The novel spark gap devices and electrodes are suitable for use in a variety of spark gap device applications. The shape of the electrodes gives rise to local field enhancements and reduces breakdown voltage jitter. Breakdown voltage jitter of approximately 5% has been measured in spark gaps according the invention. Novel electrode geometries and materials are disclosed.

  9. Spark gap with low breakdown voltage jitter

    DOE Patents [OSTI]

    Rohwein, G.J.; Roose, L.D.

    1996-04-23T23:59:59.000Z

    Novel spark gap devices and electrodes are disclosed. The novel spark gap devices and electrodes are suitable for use in a variety of spark gap device applications. The shape of the electrodes gives rise to local field enhancements and reduces breakdown voltage jitter. Breakdown voltage jitter of approximately 5% has been measured in spark gaps according the invention. Novel electrode geometries and materials are disclosed. 13 figs.

  10. Broad-band beam buncher

    DOE Patents [OSTI]

    Goldberg, David A. (Walnut Creek, CA); Flood, William S. (Berkeley, CA); Arthur, Allan A. (Martinez, CA); Voelker, Ferdinand (Orinda, CA)

    1986-01-01T23:59:59.000Z

    A broad-band beam buncher is disclosed, comprising an evacuated housing, an electron gun therein for producing an electron beam, a buncher cavity having entrance and exit openings through which the beam is directed, grids across such openings, a source providing a positive DC voltage between the cavity and the electron gun, a drift tube through which the electron beam travels in passing through such cavity, grids across the ends of such drift tube, gaps being provided between the drift tube grids and the entrance and exit grids, a modulator for supplying an ultrahigh frequency modulating signal to the drift tube for producing velocity modulation of the electrons in the beam, a drift space in the housing through which the velocity modulated electron beam travels and in which the beam is bunched, and a discharge opening from such drift tube and having a grid across such opening through which the bunched electron beam is discharged into an accelerator or the like. The buncher cavity and the drift tube may be arranged to constitute an extension of a coaxial transmission line which is employed to deliver the modulating signal from a signal source. The extended transmission line may be terminated in its characteristic impedance to afford a broad-band response and the device as a whole designed to effect broad-band beam coupling, so as to minimize variations of the output across the response band.

  11. Variation in band gap of lanthanum chromate by transition metals doping LaCr{sub 0.9}A{sub 0.1}O{sub 3} (A:Fe/Co/Ni)

    SciTech Connect (OSTI)

    Naseem, Swaleha, E-mail: wasiamu@gmail.com; Khan, Wasi, E-mail: wasiamu@gmail.com; Saad, A. A., E-mail: wasiamu@gmail.com; Shoeb, M., E-mail: wasiamu@gmail.com; Ahmed, Hilal, E-mail: wasiamu@gmail.com; Naqvi, A. H. [Centre of Excellence in Materials Science (Nanomaterials), Department of Applied Physics, Z.H. College of Engg. and Technology, Aligarh Muslim University, Aligarh-202002 (India); Husain, Shahid [Department of Physics, Aligarh Muslim University, Aligarh-202002 (India)

    2014-04-24T23:59:59.000Z

    Transition metal (Fe, Co, Ni) doped lanthanum chromate (LaCrO{sub 3}) nanoparticles (NPs) were prepared by gel combustion method and calcinated at 800°C. Microstructural studies were carried by XRD and SEM/EDS techniques. The results of structural characterization show the formation of all samples in single phase without any impurity. Optical properties were studied by UV- visible and photoluminescence techniques. The energy band gap was calculated and the variation was observed with the doping of transition metal ions. Photoluminescence spectra show the emission peak maxima for the pure LaCrO{sub 3} at about 315 nm. Influence of Fe, Co, Ni doping was studied and compared with pure lanthanum chromate nanoparticles.

  12. A study of potential high band-gap photovoltaic materials for a two step photon intermediate technique in fission energy conversion

    SciTech Connect (OSTI)

    Not Available

    1991-08-16T23:59:59.000Z

    A diamond synthesis chamber and an ion implanter have been constructed. Work has been rapidly progressing and diamond has been synthesized. There are five variables which affect the quality of diamond: (1) mass flow of methane, (2) mass flow of hydrogen, (3) filament temperature, (4) substrate temperature, and (5) substrate material. Enclosed are pictures and data of previous diamond growth experiments. Current work is focused on the conditions which produce the best quality diamond films. In this study, diamond films were deposited using a hot-filament CVD method with boron trioxide (B{sub 2}O{sub 3}) and diphosphorus pentoxide (P{sub 2}O{sub 5}) as the doping sources. P{sub 2}O{sub 5} is the only known effective phosphorus source for forming n-type semiconducting material. An RF generator has been made operation for epitaxial growth of AIN by the chemical vapor deposition method. In initial experiments with a graphite substrate, the RF generator heated the material to a temperature of 1100{degrees}C. A reactor which will use the RF generator has been built for AIN synthesis. The device should be assembled and tested by the end of August. A new process for fabricating platinum silicide photovoltaic cells has been developed. A diffused guard ring has been added to minimize leakage current. VUV to near IR capability has been developed for optical characterization. A microwave driven excimer lamp has been built and tested. Our previous work used a microwave source on an electron cyclotron heated ion source.

  13. Domain walls in gapped graphene

    E-Print Network [OSTI]

    G. W. Semenoff; V. Semenoff; Fei Zhou

    2008-05-31T23:59:59.000Z

    The electronic properties of a particular class of domain walls in gapped graphene are investigated. We show that they can support mid-gap states which are localized in the vicinity of the domain wall and propagate along its length. With a finite density of domain walls, these states can alter the electronic properties of gapped graphene significantly. If the mid-gap band is partially filled,the domain wall can behave like a one-dimensional metal embedded in a semi-conductor, and could potentially be used as a single-channel quantum wire.

  14. Domain walls in gapped graphene

    E-Print Network [OSTI]

    Semenoff, G W; Zhou, Fei

    2015-01-01T23:59:59.000Z

    The electronic properties of a particular class of domain walls in gapped graphene are investigated. We show that they can support mid-gap states which are localized in the vicinity of the domain wall and propagate along its length. With a finite density of domain walls, these states can alter the electronic properties of gapped graphene significantly. If the mid-gap band is partially filled,the domain wall can behave like a one-dimensional metal embedded in a semi-conductor, and could potentially be used as a single-channel quantum wire.

  15. Red emitting photonic devices using InGaP/InGaAlP material system

    E-Print Network [OSTI]

    Kangude, Yamini

    2005-01-01T23:59:59.000Z

    In this thesis, two red emitting photonic devices are presented using the InGaP/InGaAlP material system. InGaP/InGaAlP material system provides large flexibility in the band gap energy while being lattice matched to GaAs ...

  16. Thermovoltaic semiconductor device including a plasma filter

    DOE Patents [OSTI]

    Baldasaro, Paul F. (Clifton Park, NY)

    1999-01-01T23:59:59.000Z

    A thermovoltaic energy conversion device and related method for converting thermal energy into an electrical potential. An interference filter is provided on a semiconductor thermovoltaic cell to pre-filter black body radiation. The semiconductor thermovoltaic cell includes a P/N junction supported on a substrate which converts incident thermal energy below the semiconductor junction band gap into electrical potential. The semiconductor substrate is doped to provide a plasma filter which reflects back energy having a wavelength which is above the band gap and which is ineffectively filtered by the interference filter, through the P/N junction to the source of radiation thereby avoiding parasitic absorption of the unusable portion of the thermal radiation energy.

  17. Gap and stripline combined monitor

    DOE Patents [OSTI]

    Yin, Yan (Palo Alto, CA)

    1986-01-01T23:59:59.000Z

    A combined gap and stripline monitor device (10) for measuring the intensity and position of a charged particle beam bunch in a beam pipe of a synchotron radiation facility. The monitor has first and second beam pipe portions (11a, 11b) with an axial gap (12) therebetween. An outer pipe (14) cooperates with the first beam pipe portion (11a) to form a gap enclosure, while inner strips (23a-d) cooperate with the first beam pipe portion (11a) to form a stripline monitor, with the stripline length being the same as the gap enclosure length.

  18. Enhancement of band-to-band tunneling in mono-layer transition metal dichalcogenides two-dimensional materials by vacancy defects

    SciTech Connect (OSTI)

    Jiang, Xiang-Wei; Li, Shu-Shen [State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Gong, Jian [School of Physics Science and Technology, Inner Mongolia University, Hohhot 010021 (China); Xu, Nuo [Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720 (United States); Zhang, Jinfeng; Hao, Yue [Key Laboratory of Wide Band Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi'an 710071 (China); Wang, Lin-Wang, E-mail: lwwang@lbl.gov [Material Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2014-01-13T23:59:59.000Z

    The band-to-band tunneling of monolayer transition metal dichalcogenides nano-junction is investigated using atomistic ab initio quantum transport simulations. From the simulation, it is found that the transition metal vacancy defect in the two-dimensional MX{sub 2} (M = Mo,W; X = S,Se) band-to-band tunneling diode can dramatically boost the on-state current up to 10 times while maintaining the device sub-threshold swing. The performance enhancement mechanism is discussed in detail by examining partial density of states of the system. It is found that the transition metal vacancy induces band-gap states, which reduce the effective length of the tunneling transition region.

  19. Monolithic multi-color light emission/detection device

    SciTech Connect (OSTI)

    Wanlass, Mark W. (Golden, CO)

    1995-01-01T23:59:59.000Z

    A single-crystal, monolithic, tandem, multi-color optical transceiver device is described, including (a) an InP substrate having upper and lower surfaces, (b) a first junction on the upper surface of the InP substrate, (c) a second junction on the first junction. The first junction is preferably GaInAsP of defined composition, and the second junction is preferably InP. The two junctions are lattice matched. The second junction has a larger energy band gap than the first junction. Additional junctions having successively larger energy band gaps may be included. The device is capable of simultaneous and distinct multi-color emission and detection over a single optical fiber.

  20. Monolithic multi-color light emission/detection device

    SciTech Connect (OSTI)

    Wanlass, M.W.

    1995-02-21T23:59:59.000Z

    A single-crystal, monolithic, tandem, multi-color optical transceiver device is described, including (a) an InP substrate having upper and lower surfaces, (b) a first junction on the upper surface of the InP substrate, (c) a second junction on the first junction. The first junction is preferably GaInAsP of defined composition, and the second junction is preferably InP. The two junctions are lattice matched. The second junction has a larger energy band gap than the first junction. Additional junctions having successively larger energy band gaps may be included. The device is capable of simultaneous and distinct multi-color emission and detection over a single optical fiber. 5 figs.

  1. Compositional dependence of the luminescence of In{sub 0.49}(Al{sub {ital y}}Ga{sub 1{minus}{ital y}}){sub 0.51}P alloys near the direct{endash}indirect band-gap crossover

    SciTech Connect (OSTI)

    Nelson, J.S.; Jones, E.D. [Semiconductor Materials and Device Sciences Department, 1113, MS-0601, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)] [Semiconductor Materials and Device Sciences Department, 1113, MS-0601, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Myers, S.M.; Follstaedt, D.M. [Semiconductor Nanostructure Physics Department, 1112, MS-1414, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)] [Semiconductor Nanostructure Physics Department, 1112, MS-1414, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Hjalmarson, H.P. [Compound Semiconductor Technology Department, 1322, MS-0603, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)] [Compound Semiconductor Technology Department, 1322, MS-0603, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Schirber, J.E. [Solid State Sciences Department, 1100, MS-1437, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)] [Solid State Sciences Department, 1100, MS-1437, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Schneider, R.P. [Semiconductor Materials Department, 1311, MS-0603, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)] [Semiconductor Materials Department, 1311, MS-0603, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Fouquet, J.E.; Robbins, V.M.; Carey, K.W. [Hewlett Packard Laboratories, 3500 Deer Creek Road, Palo Alto, California 94303 (United States)] [Hewlett Packard Laboratories, 3500 Deer Creek Road, Palo Alto, California 94303 (United States)

    1996-06-01T23:59:59.000Z

    A number of complementary experimental characterization tools and theoretical band structure methods were used to determine unambiguously the band-edge luminescence as a function of Al concentration, and to place an upper limit on the short-wavelength emission of InAlGaP alloys lattice matched to GaAs. In particular, the direct-to-indirect band-gap crossing has been determined by analyzing a series of metalorganic vapor-phase-epitaxy-grown In{sub 0.49}(Al{sub {ital y}}Ga{sub 1{minus}{ital y}}){sub 0.51}P alloys lattice matched to GaAs with double-crystal x-ray analysis, Rutherford backscattering spectroscopy, pressure- and temperature-dependent photoluminescence, and transmission electron microscopy. The experimental measurements are compared to first-principles plane-wave pseudopotential band structure calculations for the ternary end points, InGaP and InAlP. The maximum room temperature direct band gap is found to be 2.24 eV, corresponding to an Al composition of {ital y}=0.52{plus_minus}0.02, in good agreement with the theoretical prediction of 0.58{plus_minus}0.05. {copyright} {ital 1996 The American Physical Society.}

  2. Predicted band structures of III-V semiconductors in wurtzite phase

    E-Print Network [OSTI]

    Amrit De; Craig E. Pryor

    2009-08-13T23:59:59.000Z

    While non-nitride III-V semiconductors typically have a zincblende structure, they may also form wurtzite crystals under pressure or when grown as nanowhiskers. This makes electronic structure calculation difficult since the band structures of wurtzite III-V semiconductors are poorly characterized. We have calculated the electronic band structure for nine III-V semiconductors in the wurtzite phase using transferable empirical pseudopotentials including spin-orbit coupling. We find that all the materials have direct gaps. Our results differ significantly from earlier {\\it ab initio} calculations, and where experimental results are available (InP, InAs and GaAs) our calculated band gaps are in good agreement. We tabulate energies, effective masses, and linear and cubic Dresselhaus zero-field spin-splitting coefficients for the zone-center states. The large zero-field spin-splitting coefficients we find may lead to new functionalities for designing devices that manipulate spin degrees of freedom.

  3. Design, Modeling and Numerical Analysis of Microwave and Optical Devices: The Multi-band Patch Antenna, Ultra Wideband Ring Filter and Plasmonic Waveguide Coupler 

    E-Print Network [OSTI]

    Liu, Ya-Chi

    2014-01-14T23:59:59.000Z

    0.3 ns, which indicates the proposed structure is very suitable for real applications. Finally, a short partially corrugated tapered waveguide for silicon-based micro-slab waveguide to plasmonic nano-gap waveguide mode conversion at the optical...

  4. Strain-engineered band parameters of graphene-like SiC monolayer

    SciTech Connect (OSTI)

    Behera, Harihar, E-mail: harihar@theglocaluniversity.in [School of Technology, The Glocal University, Mirzapur Pole, Dist.-Saharanpur, U.P.-247001, India and Department of Physics, Indian Institute of Technology Bombay, Powai, Mumbai-400076 (India); Mukhopadhyay, Gautam, E-mail: gmukh@phy.iitb.ac.in [Department of Physics, Indian Institute of Technology Bombay, Powai, Mumbai-400076 (India)

    2014-10-06T23:59:59.000Z

    Using full-potential density functional theory (DFT) calculations we show that the band gap and effective masses of charge carriers in SiC monolayer (ML-SiC) in graphene-like two-dimensional honeycomb structure are tunable by strain engineering. ML-SiC was found to preserve its flat 2D graphene-like structure under compressive strain up to 7%. A transition from indirect-to-direct gap-phase is predicted to occur for a strain value lying within the interval (1.11 %, 1.76%). In both gap-phases band gap decreases with increasing strain, although the rate of decrease is different in the two gap-phases. Effective mass of electrons show a non-linearly decreasing trend with increasing tensile strain in the direct gap-phase. The strain-sensitive properties of ML-SiC, may find applications in future strain-sensors, nanoelectromechanical systems (NEMS) and nano-optomechanical systems (NOMS) and other nano-devices.

  5. Banded electromagnetic stator core

    DOE Patents [OSTI]

    Fanning, A.W.; Gonzales, A.A.; Patel, M.R.; Olich, E.E.

    1994-04-05T23:59:59.000Z

    A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups. 5 figures.

  6. Banded electromagnetic stator core

    DOE Patents [OSTI]

    Fanning, A.W.; Gonzales, A.A.; Patel, M.R.; Olich, E.E.

    1996-06-11T23:59:59.000Z

    A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups. 5 figs.

  7. Device modeling and simulation of the performance of Cu(In1x,Gax)Se2 solar cells

    E-Print Network [OSTI]

    Anderson, Timothy J.

    on the simulation results, an optimal graded band-gap structure for the CIGS solar cell is proposed. The performance-junction Cu(In1Àx,Gax)Se2 (CIGS) solar cells. Increasing the open-circuit voltage (Voc) to improve the overallDevice modeling and simulation of the performance of Cu(In1Àx,Gax)Se2 solar cells Jiyon Song

  8. First principles investigation of scaling trends of zirconium silicate interface band offsets

    E-Print Network [OSTI]

    Dutton, Robert W.

    First principles investigation of scaling trends of zirconium silicate interface band offsets out to investigate the scaling trends of band offsets at model silicon/zirconium silicate interfaces. Owing to the d character of zirconium silicate conduction bands, the band gap and band offset are shown

  9. Optoelectronic device

    DOE Patents [OSTI]

    Bonekamp, Jeffrey E.; Boven, Michelle L.; Gaston, Ryan S.

    2014-09-09T23:59:59.000Z

    The invention is an optoelectronic device comprising an active portion which converts light to electricity or converts electricity to light, the active portion having a front side for the transmittal of the light and a back side opposite from the front side, at least two electrical leads to the active portion to convey electricity to or from the active portion, an enclosure surrounding the active portion and through which the at least two electrical leads pass wherein the hermetically sealed enclosure comprises at the front side of the active portion a barrier material which allows for transmittal of light, one or more getter materials disposed so as to not impede the transmission of light to or from the active portion, and a contiguous gap pathway to the getter material which pathway is disposed between the active portion and the barrier material.

  10. Equivalent Circuit Description of Non-compensated n-p Codoped TiO2 as Intermediate Band Solar Cells

    E-Print Network [OSTI]

    Tian-Li Feng; Guang-Wei Deng; Yi Xia; Feng-Cheng Wu; Ping Cui; Hai-Ping Lan; Zhen-Yu Zhang

    2010-12-09T23:59:59.000Z

    The novel concept of non-compensated n-p codoping has made it possible to create tunable intermediate bands in the intrinsic band gap of TiO2, making the codoped TiO2 a promising material for developing intermediate band solar cells (IBSCs). Here we investigate the quantum efficiency of such IBSCs within two scenarios - with and without current extracted from the extended intermediate band. Using the ideal equivalent circuit model, we find that the maximum efficiency of 57% in the first scenario and 53% in the second are both much higher than the Shockley-Queisser limit from single gap solar cells. We also obtain various key quantities of the circuits, a useful step in realistic development of TiO2 based solar cells invoking device integration. These equivalent circuit results are also compared with the efficiencies obtained directly from consideration of electron transition between the energy bands, and both approaches reveal the intriguing existence of double peaks in the maximum quantum efficiency as a function of the relative location of IBs.

  11. Equivalent Circuit Description of Non-compensated n-p Codoped TiO2 as Intermediate Band Solar Cells

    E-Print Network [OSTI]

    Feng, Tian-Li; Xia, Yi; Wu, Feng-Cheng; Cui, Ping; Lan, Hai-Ping; Zhang, Zhen-Yu

    2010-01-01T23:59:59.000Z

    The novel concept of non-compensated n-p codoping has made it possible to create tunable intermediate bands in the intrinsic band gap of TiO2, making the codoped TiO2 a promising material for developing intermediate band solar cells (IBSCs). Here we investigate the quantum efficiency of such IBSCs within two scenarios - with and without current extracted from the extended intermediate band. Using the ideal equivalent circuit model, we find that the maximum efficiency of 57% in the first scenario and 53% in the second are both much higher than the Shockley-Queisser limit from single gap solar cells. We also obtain various key quantities of the circuits, a useful step in realistic development of TiO2 based solar cells invoking device integration. These equivalent circuit results are also compared with the efficiencies obtained directly from consideration of electron transition between the energy bands, and both approaches reveal the intriguing existence of double peaks in the maximum quantum efficiency as a fun...

  12. Closing the Mesoscale Gap

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

    Closing the Mesoscale Gap Los Alamos proposes to fill in the gaps in our fundamental understanding of materials with MaRIE, a facility designed to gain access to the mesoscale....

  13. A study of potential high band-gap photovoltaic materials for a two step photon intermediate technique in fission energy conversion. Progress report for year one, December 1, 1990--November 30, 1991

    SciTech Connect (OSTI)

    Not Available

    1991-08-16T23:59:59.000Z

    A diamond synthesis chamber and an ion implanter have been constructed. Work has been rapidly progressing and diamond has been synthesized. There are five variables which affect the quality of diamond: (1) mass flow of methane, (2) mass flow of hydrogen, (3) filament temperature, (4) substrate temperature, and (5) substrate material. Enclosed are pictures and data of previous diamond growth experiments. Current work is focused on the conditions which produce the best quality diamond films. In this study, diamond films were deposited using a hot-filament CVD method with boron trioxide (B{sub 2}O{sub 3}) and diphosphorus pentoxide (P{sub 2}O{sub 5}) as the doping sources. P{sub 2}O{sub 5} is the only known effective phosphorus source for forming n-type semiconducting material. An RF generator has been made operation for epitaxial growth of AIN by the chemical vapor deposition method. In initial experiments with a graphite substrate, the RF generator heated the material to a temperature of 1100{degrees}C. A reactor which will use the RF generator has been built for AIN synthesis. The device should be assembled and tested by the end of August. A new process for fabricating platinum silicide photovoltaic cells has been developed. A diffused guard ring has been added to minimize leakage current. VUV to near IR capability has been developed for optical characterization. A microwave driven excimer lamp has been built and tested. Our previous work used a microwave source on an electron cyclotron heated ion source.

  14. Engineering the Electronic Band Structure for Multiband Solar Cells

    SciTech Connect (OSTI)

    Lopez, N.; Reichertz, L.A.; Yu, K.M.; Campman, K.; Walukiewicz, W.

    2010-07-12T23:59:59.000Z

    Using the unique features of the electronic band structure of GaNxAs1-x alloys, we have designed, fabricated and tested a multiband photovoltaic device. The device demonstrates an optical activity of three energy bands that absorb, and convert into electrical current, the crucial part of the solar spectrum. The performance of the device and measurements of electroluminescence, quantum efficiency and photomodulated reflectivity are analyzed in terms of the Band Anticrossing model of the electronic structure of highly mismatched alloys. The results demonstrate the feasibility of using highly mismatched alloys to engineer the semiconductor energy band structure for specific device applications.

  15. Influence of film thickness and air exposure on the transport gap of manganese phthalocyanine

    SciTech Connect (OSTI)

    Haidu, F.; Fechner, A.; Salvan, G.; Gordan, O. D.; Fronk, M.; Zahn, D. R. T. [Semiconductor Physics, Chemnitz University of Technology, D-09107 Chemnitz (Germany); Lehmann, D. [Semiconductor Physics, Chemnitz University of Technology, D-09107 Chemnitz (Germany); INNOVENT Technology Development, D-07745 Jena (Germany); Mahns, B.; Knupfer, M. [Electronic and Optical Properties Department, IFW Dresden, D-01171 Dresden (Germany)

    2013-06-15T23:59:59.000Z

    The interface formation between manganese phthalocyanine (MnPc) and cobalt was investigated combining ultraviolet photoelectron spectroscopy and inverse photoelectron spectroscopy. The transport band gap of the MnPc increases with the film thickness up to a value of (1.2 {+-} 0.3) eV while the optical band gap as determined from spectroscopic ellipsometry amounts to 0.5 eV. The gap values are smaller compared to other phthalocyanines due to metallic Mn 3d states close to the Fermi level. The transport band gap was found to open upon air exposure as a result of the disappearance of the occupied 3d electronic states.

  16. Hetero-junction photovoltaic device and method of fabricating the device

    DOE Patents [OSTI]

    Aytug, Tolga; Christen, David K; Paranthaman, Mariappan Parans; Polat, Ozgur

    2014-02-10T23:59:59.000Z

    A hetero-junction device and fabrication method in which phase-separated n-type and p-type semiconductor pillars define vertically-oriented p-n junctions extending above a substrate. Semiconductor materials are selected for the p-type and n-type pillars that are thermodynamically stable and substantially insoluble in one another. An epitaxial deposition process is employed to form the pillars on a nucleation layer and the mutual insolubility drives phase separation of the materials. During the epitaxial deposition process, the orientation is such that the nucleation layer initiates propagation of vertical columns resulting in a substantially ordered, three-dimensional structure throughout the deposited material. An oxidation state of at least a portion of one of the p-type or the n-type semiconductor materials is altered relative to the other, such that the band-gap energy of the semiconductor materials differ with respect to stoichiometric compositions and the device preferentially absorbs particular selected bands of radiation.

  17. College Gender Gaps

    E-Print Network [OSTI]

    Bronson, Mary Ann

    2013-01-01T23:59:59.000Z

    College Gender Gaps BY MARY ANN BRONSONBY MARY ANN BRONSON FALL 2013 W HY DO WOMEN ATTEND collegerelationship is crucial. Mary Ann Bronson, a Ph.D. candidate

  18. Integrated optical and electrical modeling of plasmon-enhanced thin film photovoltaics: A case-study on organic devices

    SciTech Connect (OSTI)

    Rourke, Devin [Department of Physics, University of Colorado, Boulder, Colorado 80309-0390 (United States); Ahn, Sungmo [Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, Colorado 80309-0425 (United States); Nardes, Alexandre M.; Lagemaat, Jao van de; Kopidakis, Nikos [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401 (United States); Park, Wounjhang, E-mail: won.park@colorado.edu [Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, Colorado 80309-0425 (United States); Materials Science and Engineering Program, University of Colorado, Boulder, Colorado 80303 (United States)

    2014-09-21T23:59:59.000Z

    The nanoscale light control for absorption enhancement of organic photovoltaic (OPV) devices inevitably produces strongly non-uniform optical fields. These non-uniformities due to the localized optical modes are a primary route toward absorption enhancement in OPV devices. Therefore, a rigorous modeling tool taking into account the spatial distribution of optical field and carrier generation is necessary. Presented here is a comprehensive numerical model to describe the coupled optical and electrical behavior of plasmon-enhanced polymer:fullerene bulk heterojunction (BHJ) solar cells. In this model, a position-dependent electron-hole pair generation rate that could become highly non-uniform due to photonic nanostructures is directly calculated from the optical simulations. By considering the absorption and plasmonic properties of nanophotonic gratings included in two different popular device architectures, and applying the Poisson, current continuity, and drift/diffusion equations, the model predicts quantum efficiency, short-circuit current density, and desired carrier mobility ratios for bulk heterojunction devices incorporating nanostructures for light management. In particular, the model predicts a significant degradation of device performance when the carrier species with lower mobility are generated far from the collecting electrode. Consequently, an inverted device architecture is preferred for materials with low hole mobility. This is especially true for devices that include plasmonic nanostructures. Additionally, due to the incorporation of a plasmonic nanostructure, we use simulations to theoretically predict absorption band broadening of a BHJ into energies below the band gap, resulting in a 4.8% increase in generated photocurrent.

  19. 1-ID: Sector 1, Insertion Device Beamline

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

    A No. of Poles 72 Undulator Period 3.3 cm Device Length 2.4 m Minimum Gap 11 mm Downstream insertion device No. of Poles 72 Undulator Period 2.3 cm Device Length 2.4 m Minimum...

  20. A 250 GHz photonic band gap gyrotron amplifier

    E-Print Network [OSTI]

    Nanni, Emilio A. (Emilio Alessandro)

    2013-01-01T23:59:59.000Z

    This thesis reports the theoretical and experimental investigation of a novel gyrotron traveling-wave-tube (TWT) amplifier at 250 GHz. The gyrotron amplifier designed and tested in this thesis has achieved a peak small ...

  1. Experimental study of photonic band gap accelerator structures

    E-Print Network [OSTI]

    Marsh, Roark A

    2009-01-01T23:59:59.000Z

    This thesis reports theoretical and experimental research on a novel accelerator concept using a photonic bandgap (PBG) structure. Major advances in higher order mode (HOM) damping are required for the next generation of ...

  2. Characterization of Novel Semiconductor Alloys for Band Gap Engineering

    E-Print Network [OSTI]

    Broesler, Robert Joseph

    2010-01-01T23:59:59.000Z

    including high efficiency photovoltaics and light emittingEngineering 1.2.1 High Efficiency Photovoltaics 1.2.2 High1.2.1 High Efficiency Photovoltaics There has been

  3. Correlation between surface chemistry, density and band gap in...

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

    of WO3 films. The XPS analyses indicate the formation of stoichiometric WO3 with tungsten existing in fully oxidized valence state (W6+). However, WO3 films grown at high...

  4. Characterization of Novel Semiconductor Alloys for Band Gap Engineering

    E-Print Network [OSTI]

    Broesler, Robert Joseph

    2010-01-01T23:59:59.000Z

    and pulsed laser melting (PLM) to crystallize the amorphousrich crystalline phases, where as PLM results in GaAs-richFurther study into the effects of PLM on amorphous GaNAs is

  5. Recent emission channeling studies in wide band gap semiconductors

    E-Print Network [OSTI]

    Wahl, Ulrich; Rita, E; Alves, E; Carvalho-Soares, João; De Vries, Bart; Matias, V; Vantomme, A

    2005-01-01T23:59:59.000Z

    We present results of recent emission channeling experiments on the lattice location of implanted Fe and rare earths in wurtzite GaN and ZnO. In both cases the majority of implanted atoms are found on substitutional cation sites. The root mean square displacements from the ideal substitutional Ga and Zn sites are given and the stability of the Fe and rare earth lattice location against thermal annealing is discussed.

  6. Substrate-Induced Band-Gap Opening in Epitaxial Graphene

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over Our InstagramStructure of All-Polymer. . ~0sFailureSubscribe Mark A.

  7. Substrate-Induced Band-Gap Opening in Epitaxial Graphene

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over Our InstagramStructure of All-Polymer. . ~0sFailureSubscribe Mark

  8. Substrate-Induced Band-Gap Opening in Epitaxial Graphene

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over Our InstagramStructure of All-Polymer. . ~0sFailureSubscribe MarkSubstrate-Induced

  9. Substrate-Induced Band-Gap Opening in Epitaxial Graphene

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over Our InstagramStructure of All-Polymer. . ~0sFailureSubscribe

  10. Substrate-Induced Band-Gap Opening in Epitaxial Graphene

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over Our InstagramStructure of All-Polymer. . ~0sFailureSubscribeSubstrate-Induced

  11. Method for Creating Photonic Band Gap Materials - Energy Innovation Portal

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHighand Retrievals from aRodMIT-HarvardEnergy Innovation Portal

  12. Substrate-Induced Band-Gap Opening in Epitaxial Graphene

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del SolStrengthening a solid ... StrengtheningLabSubmitting JobsSubseaSubstrate-Induced

  13. ISM band to U-NII band frequency transverter and method of frequency transversion

    DOE Patents [OSTI]

    Stepp, Jeffrey David (Grandview, MO); Hensley, Dale (Grandview, MO)

    2006-04-04T23:59:59.000Z

    A frequency transverter (10) and method for enabling bi-frequency dual-directional transfer of digitally encoded data on an RF carrier by translating between a crowded or otherwise undesirable first frequency band, such as the 2.4 GHz ISM band, and a less-crowded or otherwise desirable second frequency band, such as the 5.0 GHz-6.0 GHz U-NII band. In a preferred embodiment, the transverter (10) connects between an existing data radio (11) and its existing antenna (30), and comprises a bandswitch (12); an input RF isolating device (14); a transmuter (16); a converter (18); a dual output local oscillator (20); an output RF isolating device (22); and an antenna (24) tuned to the second frequency band. The bandswitch (12) allows for bypassing the transverter (10), thereby facilitating its use with legacy systems. The transmuter (14) and converter (16) are adapted to convert to and from, respectively, the second frequency band.

  14. ISM band to U-NII band frequency transverter and method of frequency transversion

    SciTech Connect (OSTI)

    Stepp, Jeffrey David (Grandview, MO); Hensley, Dale (Grandview, MO)

    2006-09-12T23:59:59.000Z

    A frequency transverter (10) and method for enabling bi-frequency dual-directional transfer of digitally encoded data on an RF carrier by translating between a crowded or otherwise undesirable first frequency band, such as the 2.4 GHz ISM band, and a less-crowded or otherwise desirable second frequency band, such as the 5.0 GHz 6.0 GHz U-NII band. In a preferred embodiment, the transverter (10) connects between an existing data radio (11) and its existing antenna (30), and comprises a bandswitch (12); an input RF isolating device (14); a transmuter (16); a converter (18); a dual output local oscillator (20); an output RF isolating device (22); and an antenna (24) tuned to the second frequency band. The bandswitch (12) allows for bypassing the transverter (10), thereby facilitating its use with legacy systems. The transmuter (14) and converter (16) are adapted to convert to and from, respectively, the second frequency band.

  15. Generation gaps in engineering?

    E-Print Network [OSTI]

    Kim, David J. (David Jinwoo)

    2008-01-01T23:59:59.000Z

    There is much enthusiastic debate on the topic of generation gaps in the workplace today; what the generational differences are, how to address the apparent challenges, and if the generations themselves are even real. ...

  16. Fiber optic gap gauge

    DOE Patents [OSTI]

    Wood, Billy E. (Livermore, CA); Groves, Scott E. (Brentwood, CA); Larsen, Greg J. (Brentwood, CA); Sanchez, Roberto J. (Pleasanton, CA)

    2006-11-14T23:59:59.000Z

    A lightweight, small size, high sensitivity gauge for indirectly measuring displacement or absolute gap width by measuring axial strain in an orthogonal direction to the displacement/gap width. The gap gauge includes a preferably titanium base having a central tension bar with springs connecting opposite ends of the tension bar to a pair of end connector bars, and an elongated bow spring connected to the end connector bars with a middle section bowed away from the base to define a gap. The bow spring is capable of producing an axial strain in the base proportional to a displacement of the middle section in a direction orthogonal to the base. And a strain sensor, such as a Fabry-Perot interferometer strain sensor, is connected to measure the axial strain in the base, so that the displacement of the middle section may be indirectly determined from the measurement of the axial strain in the base.

  17. SUPERCONDUCTING DEVICES

    E-Print Network [OSTI]

    Clarke, John

    2014-01-01T23:59:59.000Z

    communications. References Superconductor Applications: ~on all aspects of superconducting devices. IEEE Trans.on all aspects vf superconducting devices. The IBM Journal

  18. SUPERCONDUCTING DEVICES

    E-Print Network [OSTI]

    Clarke, John

    2014-01-01T23:59:59.000Z

    on all aspects of superconducting devices. IEEE Trans.on all aspects vf superconducting devices. The IBM JournalJ. Matisoo, The Superconducting Computer," Scientific

  19. Uncertainties in Gapped Graphene

    E-Print Network [OSTI]

    Eylee Jung; Kwang S. Kim; DaeKil Park

    2012-03-20T23:59:59.000Z

    Motivated by graphene-based quantum computer we examine the time-dependence of the position-momentum and position-velocity uncertainties in the monolayer gapped graphene. The effect of the energy gap to the uncertainties is shown to appear via the Compton-like wavelength $\\lambda_c$. The uncertainties in the graphene are mainly contributed by two phenomena, spreading and zitterbewegung. While the former determines the uncertainties in the long-range of time, the latter gives the highly oscillation to the uncertainties in the short-range of time. The uncertainties in the graphene are compared with the corresponding values for the usual free Hamiltonian $\\hat{H}_{free} = (p_1^2 + p_2^2) / 2 M$. It is shown that the uncertainties can be under control within the quantum mechanical law if one can choose the gap parameter $\\lambda_c$ freely.

  20. Mind The Gap

    E-Print Network [OSTI]

    Daniel F. Litim

    2001-04-25T23:59:59.000Z

    We discuss an optimisation criterion for the exact renormalisation group based on the inverse effective propagator, which displays a gap. We show that a simple extremisation of the gap stabilises the flow, leading to better convergence of approximate solutions towards the physical theory. This improves the reliability of truncations, most relevant for any high precision computation. These ideas are closely linked to the removal of a spurious scheme dependence and a minimum sensitivity condition. The issue of predictive power and a link to the Polchinski RG are discussed as well. We illustrate our findings by computing critical exponents for the Ising universality class.

  1. Mid-Gap Electronic States in Zn1 xMnxO. | EMSL

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

    measurements were performed on epitaxial Zn1 xMnxO films to investigate the origin of the new mid-gap band that appears upon introduction of Mn2+ into the ZnO lattice. Absorption...

  2. Codoped direct-gap semiconductor scintillators

    DOE Patents [OSTI]

    Derenzo, Stephen Edward (Pinole, CA); Bourret-Courchesne, Edith (Berkeley, CA); Weber, Marvin J. (Danville, CA); Klintenberg, Mattias K. (Berkeley, CA)

    2008-07-29T23:59:59.000Z

    Fast, bright inorganic scintillators at room temperature are based on radiative electron-hole recombination in direct-gap semiconductors, e.g. CdS and ZnO. The direct-gap semiconductor is codoped with two different impurity atoms to convert the semiconductor to a fast, high luminosity scintillator. The codopant scheme is based on dopant band to dopant trap recombination. One dopant provides a significant concentration of carriers of one type (electrons or holes) and the other dopant traps carriers of the other type. Examples include CdS:In,Te; CdS:In,Ag; CdS:In,Na; ZnO:Ga,P; ZnO:Ga,N; ZnO:Ga,S; and GaN:Ge,Mg.

  3. Codoped direct-gap semiconductor scintillators

    DOE Patents [OSTI]

    Derenzo, Stephen E.; Bourret-Courchesne, Edith; Weber, Marvin J.; Klintenberg, Mattias K.

    2006-05-23T23:59:59.000Z

    Fast, bright inorganic scintillators at room temperature are based on radiative electron-hole recombination in direct-gap semiconductors, e.g. CdS and ZnO. The direct-gap semiconductor is codoped with two different impurity atoms to convert the semiconductor to a fast, high luminosity scintillator. The codopant scheme is based on dopant band to dopant trap recombination. One dopant provides a significant concentration of carriers of one type (electrons or holes) and the other dopant traps carriers of the other type. Examples include CdS:In,Te; CdS:In,Ag; CdS:In,Na; ZnO:Ga,P; ZnO:Ga,N; ZnO:Ga,S; and GaN:Ge,Mg.

  4. Fundamentals of polycrystalline thin film materials and devices

    SciTech Connect (OSTI)

    Baron, B.N.; Birkmire, R.W.; Phillips, J.E.; Shafarman, W.N.; Hegedus, S.S.; McCandless, B.E. (Delaware Univ., Newark, DE (USA). Inst. of Energy Conversion)

    1991-01-01T23:59:59.000Z

    This report presents the results of a one-year research program on polycrystalline thin-film solar cells. The research was conducted to better understand the limitations and potential of solar cells using CuInSe{sub 2} and CdTe by systematically investigating the fundamental relationships linking material processing, material properties, and device behavior. By selenizing Cu and In layers, we fabricated device-quality CuInSe{sub 2} thin films and demonstrated a CuInSe{sub 2} solar cell with 7% efficiency. We added Ga, to increase the band gap of CuInSe{sub 2} devices to increase the open-circuit voltage to 0.55 V. We fabricated and analyzed Cu(InGa)Se{sub 2}/CuInSe{sub 2} devices to demonstrate the potential for combining the benefits of higher V{sub oc} while retaining the current-generating capacity of CuInSe{sub 2}. We fabricated an innovative superstrate device design with more than 5% efficiency, as well as a bifacial spectral-response technique for determining the electron diffusion length and optical absorption coefficient of CuInSe{sub 2} in an operational cell. The diffusion length was found to be greater than 1 {mu}m. We qualitatively modeled the effect of reducing heat treatments in hydrogen and oxidizing treatments in air on the I-V behavior of CuInSe{sub 2} devices. We also investigated post-deposition heat treatments and chemical processing and used them to fabricate a 9.6%-efficient CdTe/CdS solar cell using physical vapor deposition.

  5. GAP TESTS; COMPARISON BETWEEN UN GAP TEST AND CARD GAP TEST

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    98-36 GAP TESTS; COMPARISON BETWEEN UN GAP TEST AND CARD GAP TEST by R. BRANKA and C. MICHOT, FRANCE (tel.: 33 3 44 55 65 19, fax: 33 3 44 55 65 10) ABSTRACT: UN gap test, type 1(a) or 2(a), is the recommended test in the acceptance procedure for transport of explosives in class 1. Up to the revision

  6. Daydreaming Devices

    E-Print Network [OSTI]

    Da Ponte, Ana Sofia Lopes

    2008-01-01T23:59:59.000Z

    Daydreaming Devices is a project on aspects of daydream and the design of convertible furniture within the context of art. This thesis addresses the concepts and the design of two daydreaming devices developed during my ...

  7. Band offsets of TiZnSnO/Si heterojunction determined by x-ray photoelectron spectroscopy

    SciTech Connect (OSTI)

    Sun, R. J.; Jiang, Q. J.; Yan, W. C.; Feng, L. S.; Lu, B.; Ye, Z. Z. [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Li, X. F. [Key Laboratory of Advanced Display and System Application, Ministry of Education, Shanghai University, Shanghai 200072 (China); Li, X. D. [Xinyi PV Products (Anhui) Holdings LTD, Xinyi PV Glass Industrial Zone, No. 2 Xinyi Road, ETDZ, Wuhu 241009 (China); Lu, J. G., E-mail: lujianguo@zju.edu.cn [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Key Laboratory of Advanced Display and System Application, Ministry of Education, Shanghai University, Shanghai 200072 (China)

    2014-09-28T23:59:59.000Z

    X-ray photoelectron spectroscopy (XPS) was utilized to measure the valence band offset (?E{sub V}) of the TiZnSnO (TZTO)/Si heterojunction. TZTO films were deposited on Si (100) substrates using magnetron sputtering at room temperature. By using the Zn 2p{sub 3/2} and Sn 3d{sub 5/2} energy levels as references, the value of ?E{sub V} was calculated to be 2.69 ± 0.1 eV. Combining with the experimental optical energy band gap of 3.98 eV for TZTO extracted from the UV-vis transmittance spectrum, the conduction band offset (?E{sub C}) was deduced to be 0.17 ± 0.1 eV at the interface. Hence, the energy band alignment of the heterojunction was determined accurately, showing a type-I form. This will be beneficial for the design and application of TZTO/Si hybrid devices.

  8. Optical gain from the direct gap transition of Ge-on-Si at room temperature

    E-Print Network [OSTI]

    Liu, Jifeng

    We report direct band gap optical gain of tensile strained n+ epitaxial Ge-on-Si at room temperature, which confirms that band-engineered Ge-on-Si is a promising gain medium for monolithic optical amplifiers and lasers on Si.

  9. Band filling effects on temperature performance of intermediate band quantum wire solar cells

    SciTech Connect (OSTI)

    Kunets, Vas. P., E-mail: vkunets@uark.edu; Furrow, C. S.; Ware, M. E.; Souza, L. D. de; Benamara, M.; Salamo, G. J. [Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701 (United States); Mortazavi, M. [Department of Chemistry and Physics, University of Arkansas at Pine Bluff, Pine Bluff, Arkansas 71601 (United States)

    2014-08-28T23:59:59.000Z

    Detailed studies of solar cell efficiency as a function of temperature were performed for quantum wire intermediate band solar cells grown on the (311)A plane. A remotely doped one-dimensional intermediate band made of self-assembled In{sub 0.4}Ga{sub 0.6}As quantum wires was compared to an undoped intermediate band and a reference p-i-n GaAs sample. These studies indicate that the efficiencies of these solar cells depend on the population of the one-dimensional band by equilibrium free carriers. A change in this population by free electrons under various temperatures affects absorption and carrier transport of non-equilibrium carriers generated by incident light. This results in different efficiencies for both the doped and undoped intermediate band solar cells in comparison with the reference GaAs p-i-n solar cell device.

  10. Mind the gap

    E-Print Network [OSTI]

    M. S. Bhagwat; A. Krassnigg; P. Maris; C. D. Roberts

    2006-12-06T23:59:59.000Z

    In this summary of the application of Dyson-Schwinger equations to the theory and phenomenology of hadrons, some deductions following from a nonperturbative, symmetry-preserving truncation are highlighted, notable amongst which are results for pseudoscalar mesons. We also describe inferences from the gap equation relating to the radius of convergence of a chiral expansion, applications to heavy-light and heavy-heavy mesons, and quantitative estimates of the contribution of quark orbital angular momentum in pseudoscalar mesons; and recapitulate upon studies of nucleon electromagnetic form factors.

  11. Electrochromic devices

    DOE Patents [OSTI]

    Allemand, Pierre M. (Tucson, AZ); Grimes, Randall F. (Ann Arbor, MI); Ingle, Andrew R. (Tucson, AZ); Cronin, John P. (Tucson, AZ); Kennedy, Steve R. (Tuscon, AZ); Agrawal, Anoop (Tucson, AZ); Boulton, Jonathan M. (Tucson, AZ)

    2001-01-01T23:59:59.000Z

    An electrochromic device is disclosed having a selective ion transport layer which separates an electrochemically active material from an electrolyte containing a redox active material. The devices are particularly useful as large area architectural and automotive glazings due to there reduced back reaction.

  12. Nanotube resonator devices

    DOE Patents [OSTI]

    Jensen, Kenneth J; Zettl, Alexander K; Weldon, Jeffrey A

    2014-05-06T23:59:59.000Z

    A fully-functional radio receiver fabricated from a single nanotube is being disclosed. Simultaneously, a single nanotube can perform the functions of all major components of a radio: antenna, tunable band-pass filter, amplifier, and demodulator. A DC voltage source, as supplied by a battery, can power the radio. Using carrier waves in the commercially relevant 40-400 MHz range and both frequency and amplitude modulation techniques, successful music and voice reception has been demonstrated. Also disclosed are a radio transmitter and a mass sensor using a nanotube resonator device.

  13. Gap generation in Weyl semimetals in a model with local four-fermion interaction

    E-Print Network [OSTI]

    P. O. Sukhachov

    2014-06-25T23:59:59.000Z

    We study the gap generation in Weyl semimetals in a model with local four-fermion interaction. It is shown that there exists a critical value of coupling constant separating the symmetric and broken symmetry phases, and the corresponding phase diagram is described. The gap generation in a more general class of Weyl materials with small bare gap is studied, and the quasiparticle energy spectrum is determined. It is found that, in this case, the dynamically generated gap leads to additional splitting of the quasiparticle energy bands.

  14. Band-engineered Ge-on-Si lasers

    E-Print Network [OSTI]

    Liu, Jifeng

    We report optically-pumped Ge-on-Si lasers with direct gap emission near 1600 nm at room temperature. The Ge-on-Si material was band-engineered by tensile strain and n-type doping to compensate the energy difference between ...

  15. Cu(In,Ga)Se2 alloys are the leading choice for absorber layers in high-efficiency thin film solar cells due to their direct gap, high absorption

    E-Print Network [OSTI]

    Rockett, Angus

    film solar cells due to their direct gap, high absorption coefficient and excellent thermal stability Cu(In,Ga)Se2 are used to interpret PL results. ·No evidence of band-to-band transitions (rare in CIGS

  16. Device Performance

    SciTech Connect (OSTI)

    Not Available

    2006-06-01T23:59:59.000Z

    In the Device Performance group, within the National Center for Photovoltaic's Measurements and Characterization Division, we measure the performance of PV cells and modules with respect to standard reporting conditions--defined as a reference temperature (25 C), total irradiance (1000 Wm-2), and spectral irradiance distribution (IEC standard 60904-3). Typically, these are ''global'' reference conditions, but we can measure with respect to any reference set. To determine device performance, we conduct two general categories of measurements: spectral responsivity (SR) and current versus voltage (I-V). We usually perform these measurements using standard procedures, but we develop new procedures when required by new technologies. We also serve as an independent facility for verifying device performance for the entire PV community. We help the PV community solve its special measurement problems, giving advice on solar simulation, instrumentation for I-V measurements, reference cells, measurement procedures, and anomalous results. And we collaborate with researchers to analyze devices and materials.

  17. Controllable spin-charge transport in strained graphene nanoribbon devices

    SciTech Connect (OSTI)

    Diniz, Ginetom S., E-mail: ginetom@gmail.com; Guassi, Marcos R. [Institute of Physics, University of Brasília, 70919-970, Brasília-DF (Brazil); Qu, Fanyao [Institute of Physics, University of Brasília, 70919-970, Brasília-DF (Brazil); Department of Physics, The University of Texas at Austin, Austin, Texas 78712 (United States)

    2014-09-21T23:59:59.000Z

    We theoretically investigate the spin-charge transport in two-terminal device of graphene nanoribbons in the presence of a uniform uniaxial strain, spin-orbit coupling, exchange field, and smooth staggered potential. We show that the direction of applied strain can efficiently tune strain-strength induced oscillation of band-gap of armchair graphene nanoribbon (AGNR). It is also found that electronic conductance in both AGNR and zigzag graphene nanoribbon (ZGNR) oscillates with Rashba spin-orbit coupling akin to the Datta-Das field effect transistor. Two distinct strain response regimes of electronic conductance as function of spin-orbit couplings magnitude are found. In the regime of small strain, conductance of ZGNR presents stronger strain dependence along the longitudinal direction of strain. Whereas for high values of strain shows larger effect for the transversal direction. Furthermore, the local density of states shows that depending on the smoothness of the staggered potential, the edge states of AGNR can either emerge or be suppressed. These emerging states can be determined experimentally by either spatially scanning tunneling microscope or by scanning tunneling spectroscopy. Our findings open up new paradigms of manipulation and control of strained graphene based nanostructure for application on novel topological quantum devices.

  18. In-situ characterization of growth and interfaces in a-Si:H devices. Annual subcontract report, 1 May 1992--30 April 1993

    SciTech Connect (OSTI)

    Collins, R.W.; Wronski, C.R.; An, I.; Lu, Y.; Nguyen, H.V. [Pennsylvania State Univ., University Park, PA (United States)

    1994-02-01T23:59:59.000Z

    This report describes work to reach two goals--an individual goal and a wide-gap team goal. The individual goal was to investigate the ``top junction`` for defects using the spectroscopic ellipsometry technique. This will include an evaluation if specific defects are associated with C, B, Sn (diffusing from the transparent conducting oxide [TCO]) or Na (diffusing from the glass). It may include an assessment of the function of a graded a-SiC:H buffer layer. As defects are identified and characterized, their influence on the transport properties will be assessed. This should lead to better parameters used as input to models for the electronic materials and device performance. The goal of the wide-gap team was to demonstrate, characterize, and understand improved doped and undoped ``wide gap`` materials for use in achieving 15%-efficient stabilized photovoltaic modules (``wide gap`` materials are defined by this team to have a band gap {ge} 1.9 eV). The major conclusions of the research are discussed in the report.

  19. Plasma jet ignition device

    DOE Patents [OSTI]

    McIlwain, Michael E. (Franklin, MA); Grant, Jonathan F. (Wayland, MA); Golenko, Zsolt (North Reading, MA); Wittstein, Alan D. (Fairfield, CT)

    1985-01-15T23:59:59.000Z

    An ignition device of the plasma jet type is disclosed. The device has a cylindrical cavity formed in insulating material with an electrode at one end. The other end of the cylindrical cavity is closed by a metal plate with a small orifice in the center which plate serves as a second electrode. An arc jumping between the first electrode and the orifice plate causes the formation of a highly-ionized plasma in the cavity which is ejected through the orifice into the engine cylinder area to ignite the main fuel mixture. Two improvements are disclosed to enhance the operation of the device and the length of the plasma plume. One improvement is a metal hydride ring which is inserted in the cavity next to the first electrode. During operation, the high temperature in the cavity and the highly excited nature of the plasma breaks down the metal hydride, liberating hydrogen which acts as an additional fuel to help plasma formation. A second improvement consists of a cavity insert containing a plurality of spaced, metal rings. The rings act as secondary spark gap electrodes reducing the voltage needed to maintain the initial arc in the cavity.

  20. Multiband semiconductor compositions for photovoltaic devices

    DOE Patents [OSTI]

    Walukiewicz, Wladyslaw (Kensington, CA); Yu, Kin Man (Lafayette, CA); Wu, Junqiao (Belmont, MA)

    2012-03-06T23:59:59.000Z

    The highly mismatched alloy Zn.sub.1-yMn.sub.yO.sub.xTe.sub.1-x, 0.ltoreq.y<1 and 0band of extended states located within the band gap of the Zn.sub.1-yMn.sub.yTe host. With multiple band gaps that fall within the solar energy spectrum, Zn.sub.1-yMn.sub.yO.sub.xTe.sub.1-x is a material perfectly satisfying the conditions for single-junction photovoltaics with the potential for power conversion efficiencies surpassing 50%.

  1. Multiband semiconductor compositions for photovoltaic devices

    DOE Patents [OSTI]

    Walukiewicz, Wladyslaw; Yu, Kin Man; Wu, Junqiao

    2010-05-04T23:59:59.000Z

    The highly mismatched alloy Zn1-yMnyOxTe1-x, 0.ltoreq.y<1 and 0band of extended states located within the band gap of the Zn1-yMnyTe host. With multiple band gaps that fall within the solar energy spectrum, Zn1-yMnyOxTe1-x is a material perfectly satisfying the conditions for single-junction photovoltaics with the potential for power conversion efficiencies surpassing 50%.

  2. The Pennsylvania State University Marching Blue Band Blue Band Office

    E-Print Network [OSTI]

    Maroncelli, Mark

    The Pennsylvania State University Marching Blue Band Press Kit Blue Band Office 101 Blue Band Director vcc2@psu.edu orb1@psu.edu gad157@psu.edu (814) 865 - 3982 #12;History of the Blue Band The Marching Blue Band numbers 310 members which includes: 260 instrumentalists, 34 silks, 14 Touch of Blue

  3. Band anticrossing effects in highly mismatched semiconductor alloys

    SciTech Connect (OSTI)

    Wu, Junqiao

    2002-09-09T23:59:59.000Z

    The first five chapters of this thesis focus on studies of band anticrossing (BAC) effects in highly electronegativity- mismatched semiconductor alloys. The concept of bandgap bowing has been used to describe the deviation of the alloy bandgap from a linear interpolation. Bowing parameters as large as 2.5 eV (for ZnSTe) and close to zero (for AlGaAs and ZnSSe) have been observed experimentally. Recent advances in thin film deposition techniques have allowed the growth of semiconductor alloys composed of significantly different constituents with ever- improving crystalline quality (e.g., GaAs{sub 1-x}N{sub x} and GaP{sub 1-x}N{sub x} with x {approx}< 0.05). These alloys exhibit many novel and interesting properties including, in particular, a giant bandgap bowing (bowing parameters > 14 eV). A band anticrossing model has been developed to explain these properties. The model shows that the predominant bowing mechanism in these systems is driven by the anticrossing interaction between the localized level associated with the minority component and the band states of the host. In this thesis I discuss my studies of the BAC effects in these highly mismatched semiconductors. It will be shown that the results of the physically intuitive BAC model can be derived from the Hamiltonian of the many-impurity Anderson model. The band restructuring caused by the BAC interaction is responsible for a series of experimental observations such as a large bandgap reduction, an enhancement of the electron effective mass, and a decrease in the pressure coefficient of the fundamental gap energy. Results of further experimental investigations of the optical properties of quantum wells based on these materials will be also presented. It will be shown that the BAC interaction occurs not only between localized states and conduction band states at the Brillouin zone center, but also exists over all of k-space. Finally, taking ZnSTe and ZnSeTe as examples, I show that BAC also occurs between localized states and the valence band states. Soft x-ray fluorescence experiments provide direct evidence of the BAC interaction in these systems. In the final chapter of the thesis, I describe and summarize my studies of optical properties of wurtzite InN and related alloys. Early studies performed on InN films grown by sputtering techniques suggested a direct bandgap of {approx}1.9 eV for this semiconductor. Very recently, high-quality InN films with much higher mobility have become available by using the molecular beam epitaxy growth method. Optical experiments carried out on these samples reveal a narrow bandgap for InN of 0.77 eV, much lower than the previously accepted value. Optical properties of InGaN and InAlN ternaries on the In rich side have also been characterized and are found to be consistent with the narrow bandgap of InN. The bandgap bowing parameters in these alloys were determined. In the context of these findings, the bandgap energies of InGaN and InAlN were found to cover a wide spectral range from the infrared for InN to the ultraviolet for GaN and deep ultraviolet for AlN. The significance of this work is rooted in many important applications of nitride semiconductors in optoelectronics and solar energy conversion devices.

  4. Crystal and electronic band structure of Cu2ZnSnX4 ,,X=S and Se... photovoltaic absorbers: First-principles insights

    E-Print Network [OSTI]

    Gong, Xingao

    components, and the band gap is usually not optimal for high efficiency CIGS solar cells. Currently, designing and synthesizing novel, high-efficiency, and low cost solar cell absorbers to replace CIGS has.1063/1.3074499 An ideal thin-film solar cell absorber material should have a direct band gap around 1.3­1.5 e

  5. Triaxial strongly deformed bands in {sup 164}Hf and the effect of elevated yrast line

    SciTech Connect (OSTI)

    Ma Wenchao [Department of Physics, Mississippi State University, Mississippi State, MS 39762 (United States)

    2012-10-20T23:59:59.000Z

    Two exotic rotational bands have been identified in {sup 164}Hf and linked to known states. They are interpreted as being associated with the calculated triaxial strongly deformed (TSD) potential energy minimum. The bands are substantially stronger and are located at much lower spins than the previously discovered TSD bands in {sup 168}Hf. In addition to the proton and neutron shell gaps at large trixiality, it was proposed that the relative excitation energy of TSD bands above the yrast line plays an important role in the population of TSD bands.

  6. Partially filled intermediate band of Cr-doped GaN films

    SciTech Connect (OSTI)

    Sonoda, S. [Department of Electronics, Kyoto Institute of Technology, Kyoto 606-8585 (Japan)

    2012-05-14T23:59:59.000Z

    We investigated the band structure of sputtered Cr-doped GaN (GaCrN) films using optical absorption, photoelectron yield spectroscopy, and charge transport measurements. It was found that an additional energy band is formed in the intrinsic band gap of GaN upon Cr doping, and that charge carriers in the material move in the inserted band. Prototype solar cells showed enhanced short circuit current and open circuit voltage in the n-GaN/GaCrN/p-GaN structure compared to the GaCrN/p-GaN structure, which validates the proposed concept of an intermediate-band solar cell.

  7. Investigation of crystalline and electronic band alignment properties of GaP/Ge(111) heterostructure

    SciTech Connect (OSTI)

    Dixit, V. K.; Kumar, Shailendra; Singh, S. D.; Khamari, S. K.; Kumar, R.; Tiwari, Pragya; Sharma, T. K.; Oak, S. M. [Raja Ramanna Centre for Advanced Technology, Indore, Madhya Pradesh 452013 (India); Phase, D. M. [UGC-DAE Consortium for Scientific Research, Khandwa Road, Indore, Madhya Pradesh 452001 (India)

    2014-03-03T23:59:59.000Z

    Gallium phosphide (GaP) epitaxial layer and nanostructures are grown on n-Ge(111) substrates using metal organic vapour phase epitaxy. It is confirmed by high resolution x-ray diffraction measurements that the layer is highly crystalline and oriented with the coexistence of two domains, i.e., GaP(111)A and GaP(111)B, with an angle of 60° between them due to the formation of a wurtzite monolayer at the interface. The valence band offset between GaP and Ge is 0.7?±?0.1?eV as determined from the valence band onsets and from Kraut's method. A band alignment diagram for GaP/Ge/GeOx is also constructed which can be used to design monolithic optoelectronic integrated circuits.

  8. Electrochemical device

    DOE Patents [OSTI]

    Grimes, Patrick G. (Westfield, NJ); Einstein, Harry (Springfield, NJ); Bellows, Richard J. (Westfield, NJ)

    1988-01-12T23:59:59.000Z

    A tunnel protected electrochemical device features channels fluidically communicating between manifold, tunnels and cells. The channels are designed to provide the most efficient use of auxiliary power. The channels have a greater hydraulic pressure drop and electrical resistance than the manifold. This will provide a design with the optimum auxiliary energy requirements.

  9. Detection device

    DOE Patents [OSTI]

    Smith, J.E.

    1981-02-27T23:59:59.000Z

    The present invention is directed to a detection device comprising: (1) an entrance chamber; (2) a central chamber; and (3) an exit chamber. The central chamber includes an ionizing gas, anode, and means for connecting the anode with an external power supply and pulse counter.

  10. Elliptically polarizing adjustable phase insertion device

    DOE Patents [OSTI]

    Carr, Roger (Redwood City, CA)

    1995-01-01T23:59:59.000Z

    An insertion device for extracting polarized electromagnetic energy from a beam of particles is disclosed. The insertion device includes four linear arrays of magnets which are aligned with the particle beam. The magnetic field strength to which the particles are subjected is adjusted by altering the relative alignment of the arrays in a direction parallel to that of the particle beam. Both the energy and polarization of the extracted energy may be varied by moving the relevant arrays parallel to the beam direction. The present invention requires a substantially simpler and more economical superstructure than insertion devices in which the magnetic field strength is altered by changing the gap between arrays of magnets.

  11. Broad Band Photon Harvesting Biomolecules for Photovoltaics

    E-Print Network [OSTI]

    P. Meredith; B. J. Powell; J. Riesz; R. Vogel; D. Blake; I. Kartini; G. Will; S. Subianto

    2004-06-04T23:59:59.000Z

    We discuss the key principles of artificial photosynthesis for photovoltaic energy conversion. We demonstrate these principles by examining the operation of the so-called "dye sensitized solar cell" (DSSC) - a photoelectrochemical device which simulates the charge separation process across a nano-structured membrane that is characteristic of natural systems. These type of devices have great potential to challenge silicon semiconductor technology in the low cost, medium efficiency segment of the PV market. Ruthenium charge transfer complexes are currently used as the photon harvesting components in DSSCs. They produce a relatively broad band UV and visible response, but have long term stability problems and are expensive to manufacture. We suggest that a class of biological macromolecules called the melanins may be suitable replacements for the ruthenium complexes. They have strong, broad band absorption, are chemically and photochemically very stable, can be cheaply and easily synthesized, and are also bio-available and bio-compatible. We demonstrate a melanin-based regenerative solar cell, and discuss the key properties that are necessary for an effective broad band photon harvesting system.

  12. the ultrasonic methods find the width of a gap by measuring the time needed for a high frequency

    E-Print Network [OSTI]

    Kosmopoulos, Dimitrios I.

    of the measurement is high and there is no risk of damaging the product since the measurement is non- contact in the production process can be identi®ed and corrected as they occur, saving time, energy and labor inspection of gaps. ``Third Dimen- sion Software Ltd.'' [7] has implemented a device called ``Gap Gun

  13. Diversionary device

    DOE Patents [OSTI]

    Grubelich, Mark C. (Albuquerque, NM)

    2001-01-01T23:59:59.000Z

    A diversionary device has a housing having at least one opening and containing a non-explosive propellant and a quantity of fine powder packed within the housing, with the powder being located between the propellant and the opening. When the propellant is activated, it has sufficient energy to propel the powder through the opening to produce a cloud of powder outside the housing. An igniter is also provided for igniting the cloud of powder to create a diversionary flash and bang, but at a low enough pressure to avoid injuring nearby people.

  14. OLED devices

    DOE Patents [OSTI]

    Sapochak, Linda Susan [Arlington, VA; Burrows, Paul Edward [Kennewick, WA; Bimalchandra, Asanga [Richland, WA

    2011-02-22T23:59:59.000Z

    An OLED device having an emission layer formed of an ambipolar phosphine oxide host material and a dopant, a hole transport layer in electrical communication with an anode, an electron transport layer in communication with a cathode, wherein the HOMO energy of the hole transport layer is substantially the same as the HOMO energy of the ambipolar host in the emission layer, and the LUMO energy of the electron transport layer is substantially the same as the LUMO energy of the ambipolar host in the emission layer.

  15. Electrochromic device

    SciTech Connect (OSTI)

    Schwendemanm, Irina G. (Wexford, PA); Polcyn, Adam D. (Pittsburgh, PA); Finley, James J. (Pittsburgh, PA); Boykin, Cheri M. (Kingsport, TN); Knowles, Julianna M. (Apollo, PA)

    2011-03-15T23:59:59.000Z

    An electrochromic device includes a first substrate spaced from a second substrate. A first conductive member is formed over at least a portion of the first substrate. A first electrochromic material is formed over at least a portion of the first conductive member. The first electrochromic material includes an organic material. A second conductive member is formed over at least a portion of the second substrate. A second electrochromic material is formed over at least a portion of the second conductive member. The second electrochromic material includes an inorganic material. An ionic liquid is positioned between the first electrochromic material and the second electrochromic material.

  16. Thermoplastic tape compaction device

    DOE Patents [OSTI]

    Campbell, V.W.

    1994-12-27T23:59:59.000Z

    A device is disclosed for bonding a thermoplastic tape to a substrate to form a fully consolidated composite. This device has an endless chain associated with a frame so as to rotate in a plane that is perpendicular to a long dimension of the tape, the chain having pivotally connected chain links with each of the links carrying a flexible foot member that extends outwardly from the chain. A selected number of the foot members contact the tape, after the heating thereof, to cause the heated tape to bond to the substrate. The foot members are each a thin band of metal oriented transversely to the chain, with a flexibility and width and length to contact the tape so as to cause the tape to conform to the substrate to achieve consolidation of the tape and the substrate. A biased leaf-type spring within the frame bears against an inner surface of the chain to provide the compliant pressure necessary to bond the tape to the substrate. The chain is supported by sprockets on shafts rotatably supported in the frame and, in one embodiment, one of the shafts has a drive unit to produce rotation such that the foot members in contact with the tape move at the same speed as the tape. Cooling jets are positioned along the frame to cool the resultant consolidated composite. 5 figures.

  17. THE ENERGY GAP IN NUCLEAR MATTER

    E-Print Network [OSTI]

    Emery, V.J.

    2008-01-01T23:59:59.000Z

    of Physics, The Ohio State University, THE ENERGY GAP INEnergy Commission. + Permanent addross: Columbus, Ohio.

  18. Modeling integrated photovoltaic-electrochemical devices using steady-state equivalent circuits

    E-Print Network [OSTI]

    Winkler, Mark Thomas

    We describe a framework for efficiently coupling the power output of a series-connected string of single-band-gap solar cells to an electrochemical process that produces storable fuels. We identify the fundamental efficiency ...

  19. Virtual gap dielectric wall accelerator

    DOE Patents [OSTI]

    Caporaso, George James; Chen, Yu-Jiuan; Nelson, Scott; Sullivan, Jim; Hawkins, Steven A

    2013-11-05T23:59:59.000Z

    A virtual, moving accelerating gap is formed along an insulating tube in a dielectric wall accelerator (DWA) by locally controlling the conductivity of the tube. Localized voltage concentration is thus achieved by sequential activation of a variable resistive tube or stalk down the axis of an inductive voltage adder, producing a "virtual" traveling wave along the tube. The tube conductivity can be controlled at a desired location, which can be moved at a desired rate, by light illumination, or by photoconductive switches, or by other means. As a result, an impressed voltage along the tube appears predominantly over a local region, the virtual gap. By making the length of the tube large in comparison to the virtual gap length, the effective gain of the accelerator can be made very large.

  20. Majorana Flat Bands in s-Wave Gapless Topological Superconductors

    E-Print Network [OSTI]

    Shusa Deng; Gerardo Ortiz; Amrit Poudel; Lorenza Viola

    2014-04-28T23:59:59.000Z

    We demonstrate how the non-trivial interplay between spin-orbit coupling and nodeless $s$-wave superconductivity can drive a fully gapped two-band topological insulator into a time-reversal invariant gapless topological superconductor supporting symmetry-protected Majorana flat bands. We characterize topological phase diagrams by a ${\\mathbb Z}_2 \\times{\\mathbb Z}_2$ partial Berry-phase invariant, and show that, despite the trivial crystal geometry, no unique bulk-boundary correspondence exists. We trace this behavior to the anisotropic quasiparticle bulk gap closing, linear vs. quadratic, and argue that this provides a unifying principle for gapless topological superconductivity. Experimental implications for tunneling conductance measurements are addressed, relevant for lead chalcogenide materials.

  1. Temperature dependent band offsets in PbSe/PbEuSe quantum well heterostructures

    SciTech Connect (OSTI)

    Simma, M.; Bauer, G.; Springholz, G. [Institut fuer Halbleiter und Festkoerperphysik, Johannes Kepler Universitaet, A-4040 Linz (Austria)

    2012-10-22T23:59:59.000Z

    The band offsets of PbSe/Pb{sub 1-x}Eu{sub x}Se multi-quantum wells grown by molecular beam epitaxy are determined as a function of temperature and europium content using temperature-modulated differential transmission spectroscopy. The confined quantum well states in the valence and conduction bands are analyzed using a k{center_dot}p model with envelope function approximation. From the fit of the experimental data, the normalized conduction band offset is determined as 0.45{+-}0.15 of the band gap difference, independently of Eu content up to 14% and temperature from 20 to 300 K.

  2. Valence and conduction band alignment at ScN interfaces with 3C-SiC (111) and 2H-GaN (0001)

    SciTech Connect (OSTI)

    King, Sean W., E-mail: sean.king@intel.com [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Logic Technology Development, Intel Corporation, Hillsboro, Oregon 97124 (United States); Nemanich, Robert J. [Department of Physics, North Carolina State University, Raleigh, North Carolina 27695 (United States); Department of Physics, Arizona State University, Tempe, Arizona 85281 (United States); Davis, Robert F. [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)

    2014-08-25T23:59:59.000Z

    In order to understand and predict the behavior of future scandium nitride (ScN) semiconductor heterostructure devices, we have utilized in situ x-ray and ultra-violet photoelectron spectroscopy to determine the valence band offset (VBO) present at ScN/3C-SiC (111) and 2H-GaN (0001)/ScN (111) interfaces formed by ammonia gas source molecular beam epitaxy. The ScN/3C-SiC (111) VBO was dependent on the ScN growth temperature and resistivity. VBOs of 0.4?±?0.1 and 0.1?±?0.1?eV were, respectively, determined for ScN grown at 925?°C (low resistivity) and 800?°C (high resistivity). Using the band-gaps of 1.6?±?0.2 and 1.4?±?0.2?eV previously determined by reflection electron energy loss spectroscopy for the 925 and 800?°C ScN films, the respective conduction band offsets (CBO) for these interfaces were 0.4?±?0.2 and 0.9?±?0.2?eV. For a GaN (0001) interface with 925?°C ScN (111), the VBO and CBO were similarly determined to be 0.9?±?0.1 and 0.9?±?0.2?eV, respectively.

  3. Multiple input electrode gap controller

    DOE Patents [OSTI]

    Hysinger, C.L.; Beaman, J.J.; Melgaard, D.K.; Williamson, R.L.

    1999-07-27T23:59:59.000Z

    A method and apparatus for controlling vacuum arc remelting (VAR) furnaces by estimation of electrode gap based on a plurality of secondary estimates derived from furnace outputs. The estimation is preferably performed by Kalman filter. Adaptive gain techniques may be employed, as well as detection of process anomalies such as glows. 17 figs.

  4. Multiple input electrode gap controller

    DOE Patents [OSTI]

    Hysinger, Christopher L. (Austin, TX); Beaman, Joseph J. (Austin, TX); Melgaard, David K. (Albuquerque, NE); Williamson, Rodney L. (Albuquerque, NE)

    1999-01-01T23:59:59.000Z

    A method and apparatus for controlling vacuum arc remelting (VAR) furnaces by estimation of electrode gap based on a plurality of secondary estimates derived from furnace outputs. The estimation is preferably performed by Kalman filter. Adaptive gain techniques may be employed, as well as detection of process anomalies such as glows.

  5. Band Offsets of InGaP/GaAs Heterojunctions by Scanning Tunneling Spectroscopy Y. Dong and R. M. Feenstra

    E-Print Network [OSTI]

    Feenstra, Randall

    1 Band Offsets of InGaP/GaAs Heterojunctions by Scanning Tunneling Spectroscopy Y. Dong and R. M Abstract Scanning tunneling microscopy and spectroscopy are used to study InGaP/GaAs heterojunctions computation of the tunnel current. Curve fitting of theory to experiment is performed. Using an InGaP band gap

  6. Laser device

    DOE Patents [OSTI]

    Scott, Jill R. (Idaho Falls, ID); Tremblay, Paul L. (Idaho Falls, ID)

    2007-07-10T23:59:59.000Z

    A laser device includes a target position, an optical component separated a distance J from the target position, and a laser energy source separated a distance H from the optical component, distance H being greater than distance J. A laser source manipulation mechanism exhibits a mechanical resolution of positioning the laser source. The mechanical resolution is less than a spatial resolution of laser energy at the target position as directed through the optical component. A vertical and a lateral index that intersect at an origin can be defined for the optical component. The manipulation mechanism can auto align laser aim through the origin during laser source motion. The laser source manipulation mechanism can include a mechanical index. The mechanical index can include a pivot point for laser source lateral motion and a reference point for laser source vertical motion. The target position can be located within an adverse environment including at least one of a high magnetic field, a vacuum system, a high pressure system, and a hazardous zone. The laser source and an electro-mechanical part of the manipulation mechanism can be located outside the adverse environment. The manipulation mechanism can include a Peaucellier linkage.

  7. Physical properties and band structure of reactive molecular beam epitaxy grown oxygen engineered HfO{sub 2{+-}x}

    SciTech Connect (OSTI)

    Hildebrandt, Erwin; Kurian, Jose; Alff, Lambert [Institute of Materials Science, Technische Universitaet Darmstadt, 64287 Darmstadt (Germany)

    2012-12-01T23:59:59.000Z

    We have conducted a detailed thin film growth structure of oxygen engineered monoclinic HfO{sub 2{+-}x} grown by reactive molecular beam epitaxy. The oxidation conditions induce a switching between (111) and (002) texture of hafnium oxide. The band gap of oxygen deficient hafnia decreases with increasing amount of oxygen vacancies by more than 1 eV. For high oxygen vacancy concentrations, defect bands form inside the band gap that induce optical transitions and p-type conductivity. The resistivity changes by several orders of magnitude as a function of oxidation conditions. Oxygen vacancies do not give rise to ferromagnetic behavior.

  8. Broad band waveguide spectrometer

    SciTech Connect (OSTI)

    Goldman, D.S.

    1995-08-29T23:59:59.000Z

    A spectrometer is disclosed for analyzing a sample of material utilizing a broad band source of electromagnetic radiation and a detector. The spectrometer employs a waveguide possessing an entry and an exit for the electromagnetic radiation emanating from the source. The waveguide further includes a surface between the entry and exit portions which permits interaction between the electromagnetic radiation passing through the waveguide and a sample material. A tapered portion forms a part of the entry of the waveguide and couples the electromagnetic radiation emanating from the source to the waveguide. The electromagnetic radiation passing from the exit of the waveguide is captured and directed to a detector for analysis. 16 figs.

  9. Broad band waveguide spectrometer

    DOE Patents [OSTI]

    Goldman, Don S. (Folsom, CA)

    1995-01-01T23:59:59.000Z

    A spectrometer for analyzing a sample of material utilizing a broad band source of electromagnetic radiation and a detector. The spectrometer employs a waveguide possessing an entry and an exit for the electromagnetic radiation emanating from the source. The waveguide further includes a surface between the entry and exit portions which permits interaction between the electromagnetic radiation passing through the wave guide and a sample material. A tapered portion forms a part of the entry of the wave guide and couples the electromagnetic radiation emanating from the source to the waveguide. The electromagnetic radiation passing from the exit of the waveguide is captured and directed to a detector for analysis.

  10. Hard-gapped Holographic Superconductors

    E-Print Network [OSTI]

    Pallab Basu; Jianyang He; Anindya Mukherjee; Hsien-Hang Shieh

    2009-12-05T23:59:59.000Z

    In this work we discuss the zero temperature limit of a "p-wave" holographic superconductor. The bulk description consists of a non-Abelian SU(2) gauge fields minimally coupled to gravity. We numerically construct the zero temperature solution which is the gravity dual of the superconducting ground state of the "p-wave" holographic superconductors. The solution is a smooth soliton with zero horizon size and shows an emergent conformal symmetry in the IR. We found the expected superconducting behavior. Using the near horizon analysis we show that the system has a "hard gap" for the relevant gauge field fluctuations. At zero temperature the real part of the conductivity is zero for an excitation frequency less than the gap frequency. This is in contrast with what has been observed in similar scalar- gravity-gauge systems (holographic superconductors). We also discuss the low but finite temperature behavior of our solution.

  11. The History of Cranfills Gap ISD

    E-Print Network [OSTI]

    Rudd, Charla J

    2013-05-06T23:59:59.000Z

    of Bosque County, Texas ....................................... 30 4 Topographical Map of Cranfills Gap ....................................................... 34 5 Upper Meridian Creek Settlement... ............................................................ 36 6 Topographical Map of German Settlement .............................................. 37 7 Cranfills Gap Land Deed, 1888 ............................................................... 46 8 Dream Stage to Infancy Stage...

  12. Medical Device Reliability BIOMATERIALS

    E-Print Network [OSTI]

    NEMI Medical Electronics team to address short- and long-term reliability issues with medical devices. OurMedical Device Reliability BIOMATERIALS Our goal is to provide medical device manufacturers, and consistency of active implantable medical devices. These devices, including pacemakers, cardiac defibrillators

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

    E-Print Network [OSTI]

    Wu, Junqiao

    Low gap amorphous GaN1-xAsx alloys grown on glass substrate K. M. Yu,1,a S. V. Novikov,2 R September 2010 Amorphous GaN1-xAsx layers with As content in the range of x=0.1 to 0.6 were grown defined optical absorption edges. The measured band gap values for the crystalline and amorphous GaN1-x

  14. Air Gap Tunin Yilin Mao, Yashwanth

    E-Print Network [OSTI]

    Elsherbeni, Atef Z.

    Air Gap Tunin Yilin Mao, Yashwanth Electrical Engineering Departm The Unive ymao1@olemiss.edu, ypadooru@ Abstract-- An adjustable air gap was proposed the resonant frequency of patch antennas the frequency of coaxially fed p center conductor has to be de-soldered and r time the width of the air gap

  15. Calibration curves for some standard Gap Tests

    SciTech Connect (OSTI)

    Bowman, A.L.; Sommer, S.C.

    1989-01-01T23:59:59.000Z

    The relative shock sensitivities of explosive compositions are commonly assessed using a family of experiments that can be described by the generic term ''Gap Test.'' Gap tests include a donor charge, a test sample, and a spacer, or gap, between two explosives charges. The donor charge, gap material, and test dimensions are held constant within each different version of the gap test. The thickness of the gap is then varied to find the value at which 50% of the test samples will detonate. The gap tests measure the ease with a high-order detonation can be established in the test explosive, or the ''detonability,'' of the explosive. Test results are best reported in terms of the gap thickness at the 50% point. It is also useful to define the shock pressure transmitted into the test sample at the detonation threshold. This requires calibrating the gap test in terms of shock pressure in the gap as a function of the gap thickness. It also requires a knowledge of the shock Hugoniot of the sample explosive. We used the 2DE reactive hydrodynamic code with Forest Fire burn rates for the donor explosives to calculate calibration curves for several gap tests. The model calculations give pressure and particle velocity on the centerline of the experimental set-up and provide information about the curvature and pulse width of the shock wave. 10 refs., 1 fig.

  16. Genetic-Algorithm Discovery of a Direct-Gap and Optically Allowed Superstructure from Indirect-Gap Si and Ge Semiconductors

    SciTech Connect (OSTI)

    d'Avezac, M.; Luo, J. W.; Chanier, T.; Zunger, A.

    2012-01-13T23:59:59.000Z

    Combining two indirect-gap materials - with different electronic and optical gaps - to create a direct gap material represents an ongoing theoretical challenge with potentially rewarding practical implications, such as optoelectronics integration on a single wafer. We provide an unexpected solution to this classic problem, by spatially melding two indirect-gap materials (Si and Ge) into one strongly dipole-allowed direct-gap material. We leverage a combination of genetic algorithms with a pseudopotential Hamiltonian to search through the astronomic number of variants of Si{sub n}/Ge{sub m}/.../Si{sub p}/Ge{sub q} superstructures grown on (001) Si{sub 1-x}Ge{sub x}. The search reveals a robust configurational motif - SiGe{sub 2}Si{sub 2}Ge{sub 2}SiGe{sub n} on (001) Si{sub x}Ge{sub 1-x} substrate (x {le} 0.4) presenting a direct and dipole-allowed gap resulting from an enhanced {Gamma}-X coupling at the band edges.

  17. Connector device for building integrated photovoltaic device

    SciTech Connect (OSTI)

    Keenihan, James R.; Langmaid, Joseph A.; Eurich, Gerald K.; Lesniak, Michael J.; Mazor, Michael H.; Cleereman, Robert J.; Gaston, Ryan S.

    2014-06-03T23:59:59.000Z

    The present invention is premised upon a connector device and method that can more easily electrically connect a plurality of PV devices or photovoltaic system components and/or locate these devices/components upon a building structure. It also may optionally provide some additional sub-components (e.g. at least one bypass diode and/or an indicator means) and may enhance the serviceability of the device.

  18. Operated device estimation framework

    E-Print Network [OSTI]

    Rengarajan, Janarthanan

    2009-05-15T23:59:59.000Z

    Protective device estimation is a challenging task because there are numerous protective devices present in a typical distribution system. Among various protective devices, auto-reclosers and fuses are the main overcurrent protection on distribution...

  19. Evidence of Eu{sup 2+} 4f electrons in the valence band spectra of EuTiO{sub 3} and EuZrO{sub 3}

    SciTech Connect (OSTI)

    Kolodiazhnyi, T. [National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Valant, M. [Materials Research Laboratory, University of Nova Gorica, Vipavska 13, 5000 Nova Gorica (Slovenia); Williams, J. R. [International Center for Young Scientists (ICYS), MANA, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Bugnet, M.; Botton, G. A. [Department of Materials Science and Engineering, McMaster University, Hamilton, Ontario L8S 4L7 (Canada); Ohashi, N. [International Center for Materials Nanoarchitectonics, MANA, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Sakka, Y. [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)

    2012-10-15T23:59:59.000Z

    We report on optical band gap and valence electronic structure of two Eu{sup 2+}-based perovskites, EuTiO{sub 3} and EuZrO{sub 3} as revealed by diffuse optical scattering, electron energy loss spectroscopy, and valence-band x-ray photoelectron spectroscopy. The data show good agreement with the first-principles studies in which the top of the valence band structure is formed by the narrow Eu 4f{sup 7} electron band. The O 2p band shows the features similar to those of the Ba(Sr)TiO{sub 3} perovskites except that it is shifted to higher binding energies. Appearance of the Eu{sup 2+} 4f{sup 7} band is a reason for narrowing of the optical band gap in the title compounds as compared to their Sr-based analogues.

  20. FAQS Gap Analysis Qualification Card - Senior Technical Safety...

    Office of Environmental Management (EM)

    Gap Analysis Qualification Card - Senior Technical Safety Manager FAQS Gap Analysis Qualification Card - Senior Technical Safety Manager Functional Area Qualification Standard Gap...

  1. Influence of Al doping on the critical fields and gap values in magnesium diboride single crystals T. Klein,1,2 L. Lyard,1 J. Marcus,1 C. Marcenat,3 P. Szab,4 Z. Hol'anov,4 P. Samuely,4 B. W. Kang,5 H-J. Kim,5

    E-Print Network [OSTI]

    Boyer, Edmond

    that MgB2 belongs to an origi- nal class of superconductors in which two weakly coupled bands with very the existence of two distinct superconducting gaps. One of the main consequence of this two-band superconduc of the superconducting gaps with Al doping remains controversial. Whereas Gonnelli et al.15 sug- gested that the small

  2. Radiation response analysis of wide-gap p-AlInGaP for superhigh-efficiency space photovoltaics

    SciTech Connect (OSTI)

    Khan, Aurangzeb; Marupaduga, S.; Anandakrishnan, S.S.; Alam, M.; Ekins-Daukes, N.J.; Lee, H.S.; Sasaki, T.; Yamaguchi, M.; Takamoto, T.; Agui, T.; Kamimura, K.; Kaneiwa, M.; Imazumi, M. [Department of Electrical and Computer Engineering, University of South Alabama, Mobile, Alabama 36688 (United States); Toyota Technological Institute, Nagoya (Japan); Sharp Corporation, Nara (Japan); JAXA, Tsukuba (Japan)

    2004-11-29T23:59:59.000Z

    We present here the direct observation of the majority and minority carrier defects generation from wide-band-gap (2.04 eV) and thick (2 {mu}m) p-AlInGaP diodes and solar cells structures before and after 1 MeV electron irradiation by deep level transient spectroscopy (DLTS). One dominant hole-emitting trap H1 (E{sub V}+0.37{+-}0.05 eV) and two electron-emitting traps, E1 (E{sub C}-0.22{+-}0.04 eV) and E3 (E{sub C}-0.78{+-}0.05 eV) have been observed in the temperature range, which we could scan by DLTS. Detailed analysis of the minority carrier injection annealing experiment reveals that the H1 center has shown the same annealing characteristics, which has been previously observed in all phosphide-based materials such as InP, InGaP, and InGaAsP. The annealing property of the radiation-induced defects in p-AlInGaP reveals that multijunction solar cells and other optoelectronic devices such as light-emitting diodes based on this material could be considerably better to Si and GaAs in a radiation environment.

  3. Ultra high vacuum broad band high power microwave window

    DOE Patents [OSTI]

    Nguyen-Tuong, Viet (Seaford, VA); Dylla, III, Henry Frederick (Yorktown, VA)

    1997-01-01T23:59:59.000Z

    An improved high vacuum microwave window has been developed that utilizes high density polyethylene coated on two sides with SiOx, SiNx, or a combination of the two. The resultant low dielectric and low loss tangent window creates a low outgassing, low permeation seal through which broad band, high power microwave energy may be passed. No matching device is necessary and the sealing technique is simple. The features of the window are broad band transmission, ultra-high vacuum compatibility with a simple sealing technique, low voltage standing wave ratio, high power transmission and low cost.

  4. Ultra high vacuum broad band high power microwave window

    DOE Patents [OSTI]

    Nguyen-Tuong, V.; Dylla, H.F. III

    1997-11-04T23:59:59.000Z

    An improved high vacuum microwave window has been developed that utilizes high density polyethylene coated on two sides with SiOx, SiNx, or a combination of the two. The resultant low dielectric and low loss tangent window creates a low outgassing, low permeation seal through which broad band, high power microwave energy may be passed. No matching device is necessary and the sealing technique is simple. The features of the window are broad band transmission, ultra-high vacuum compatibility with a simple sealing technique, low voltage standing wave ratio, high power transmission and low cost. 5 figs.

  5. MI Gap Clearing Kicker Magnet Design Review

    SciTech Connect (OSTI)

    Jensen, Chris; /Fermilab

    2008-10-01T23:59:59.000Z

    The kicker system requirements were originally conceived for the NOvA project. NOvA is a neutrino experiment located in Minnesota. To achieve the desired neutrino flux several upgrades are required to the accelerator complex. The Recycler will be used as a proton pre-injector for the Main Injector (MI). As the Recycler is the same size as the MI, it is possible to do a single turn fill ({approx}11 {micro}sec), minimizing the proton injection time in the MI cycle and maximizing the protons on target. The Recycler can then be filled with beam while the MI is ramping to extract beam to the target. To do this requires two new transfer lines. The existing Recycler injection line was designed for 10{pi} pbar beams, not the 20{pi} proton beams we anticipate from the Booster. The existing Recycler extraction line allows for proton injection through the MI, while we want direct injection from the Booster. These two lines will be decommissioned. The new injection line from the MI8 line into the Recycler will start at 848 and end with injection kickers at RR104. The new extraction line in the RR30 straight section will start with a new extraction kicker at RR232 and end with new MI injection kickers at MI308. Finally, to reduce beam loss activation in the enclosure, a new gap clearing kicker will be used to extract uncaptured beam created during the slip stack injection process down the existing dump line. It was suggested that the MI could benefit from this type of system immediately. This led to the early installation of the gap clearing system in the MI, followed by moving the system to Recycler during NOvA. The specifications also changed during this process. Initially the rise and fall time requirements were 38 ns and the field stability was {+-}1%. The 38 ns is based on having a gap of 2 RF buckets between injections. (There are 84 RF buckets that can be filled from the Booster for each injection, but 82 would be filled with beam. MI and Recycler contain 588 RF buckets.) A rough cost/benefit analysis showed that increasing the number of empty buckets to 3 decreased the kicker system cost by {approx}30%. This could be done while not extending the running time since this is only a 1% reduction in protons per pulse, hence the rise and fall time are now 57 ns. Additionally, the {+-}1% tolerance would have required a fast correction kicker while {+-}3% could be achieved without this kicker. The loosened tolerance was based on experience on wide band damping systems in the MI. A higher power wideband damping system is a better use of the resources as it can be used to correct for multiple sources of emittance growth. Finally, with the use of this system for MI instead of Recycler, the required strength grew from 1.2 mrad to 1.7 mrad. The final requirements for this kicker are listed.

  6. Size-Dependent Optical and Electrochemical Energy Gaps Comparison of CdSe Nanolusters Meghan B. Teunis, Katie N. Lawrence, and Sukanta Dolai

    E-Print Network [OSTI]

    Zhou, Yaoqi

    including the designing of photovoltaic devices and photocatalysts. These properties occur as a result that a significant amount of charging energy is involved in the electrochemical energy gap. The effect

  7. Goncu, JASA-EL Exploiting pattern transformation to tune phononic band

    E-Print Network [OSTI]

    Luding, Stefan

    .05 × 103 kg/m3 , Young's modulus Er = 360 kPa, shear modulus Gr = 120 kPa and longitudinal speed of sound . The attenuation of electromagnetic, acoustic or elastic waves in certain frequency ranges known as band gaps numerically the propagation of elastic waves in a 2D bi-disperse granular crystal composed of large (and soft

  8. Photonic band structures of periodic arrays of pores in a metallic host

    E-Print Network [OSTI]

    Stroud, David

    . Scherer, O. Painter, B. D'Urso, R. Lee, and A. Yariv, "InGaAsP photonic band gap crystal membrane mi Crystal Waveguides," Phys. Rev. Lett. 77, 3787­3790 (1996). 6. O. Painter, R. K. Lee, A. Scherer, A. Yariv Spontaneous Emission in Solid-State Physics and Electronics," Phys. Rev. Lett. 58, 2059­2062 (1987). 4. A

  9. The effect of spin-orbit coupling in band structure of few-layer graphene

    SciTech Connect (OSTI)

    Sahdan, Muhammad Fauzi, E-mail: sahdan89@yahoo.co.id; Darma, Yudi, E-mail: sahdan89@yahoo.co.id [Department of Physics, Institut Teknologi Bandung, Jalan Ganesa 10, Bandung 40132 (Indonesia)

    2014-03-24T23:59:59.000Z

    Topological insulators are electronic materials that have a bulk band gap like an ordinary insulator but have protected conducting states on their edge or surface. This can be happened due to spin-orbit coupling and time-reversal symmetry. Moreover, the edge current flows through their edge or surface depends on its spin orientation and also it is robust against non-magnetic impurities. Therefore, topological insulators are predicted to be useful ranging from spintronics to quantum computation. Graphene was first predicted to be the precursor of topological insulator by Kane-Mele. They developed a Hamiltonian model to describe the gap opening in graphene. In this work, we investigate the band structure of few-layer graphene by using this model with analytical approach. The results of our calculations show that the gap opening occurs at K and K’ point, not only in single layer, but also in bilayer and trilayer graphene.

  10. Microfabricated bulk wave acoustic bandgap device

    DOE Patents [OSTI]

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

    2010-06-08T23:59:59.000Z

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

  11. Microfabricated bulk wave acoustic bandgap device

    DOE Patents [OSTI]

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

    2010-11-23T23:59:59.000Z

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

  12. Elliptically polarizing adjustable phase insertion device

    DOE Patents [OSTI]

    Carr, R.

    1995-01-17T23:59:59.000Z

    An insertion device for extracting polarized electromagnetic energy from a beam of particles is disclosed. The insertion device includes four linear arrays of magnets which are aligned with the particle beam. The magnetic field strength to which the particles are subjected is adjusted by altering the relative alignment of the arrays in a direction parallel to that of the particle beam. Both the energy and polarization of the extracted energy may be varied by moving the relevant arrays parallel to the beam direction. The present invention requires a substantially simpler and more economical superstructure than insertion devices in which the magnetic field strength is altered by changing the gap between arrays of magnets. 3 figures.

  13. Dilute Group III-V nitride intermediate band solar cells with contact blocking layers

    DOE Patents [OSTI]

    Walukiewicz, Wladyslaw (Kensington, CA); Yu, Kin Man (Lafayette, CA)

    2012-07-31T23:59:59.000Z

    An intermediate band solar cell (IBSC) is provided including a p-n junction based on dilute III-V nitride materials and a pair of contact blocking layers positioned on opposite surfaces of the p-n junction for electrically isolating the intermediate band of the p-n junction by blocking the charge transport in the intermediate band without affecting the electron and hole collection efficiency of the p-n junction, thereby increasing open circuit voltage (V.sub.OC) of the IBSC and increasing the photocurrent by utilizing the intermediate band to absorb photons with energy below the band gap of the absorber layers of the IBSC. Hence, the overall power conversion efficiency of a IBSC will be much higher than an conventional single junction solar cell. The p-n junction absorber layers of the IBSC may further have compositionally graded nitrogen concentrations to provide an electric field for more efficient charge collection.

  14. Narrow gap electronegative capacitive discharges

    SciTech Connect (OSTI)

    Kawamura, E.; Lieberman, M. A.; Lichtenberg, A. J. [Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720 (United States)] [Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720 (United States)

    2013-10-15T23:59:59.000Z

    Narrow gap electronegative (EN) capacitive discharges are widely used in industry and have unique features not found in conventional discharges. In this paper, plasma parameters are determined over a range of decreasing gap length L from values for which an electropositive (EP) edge exists (2-region case) to smaller L-values for which the EN region connects directly to the sheath (1-region case). Parametric studies are performed at applied voltage V{sub rf}=500 V for pressures of 10, 25, 50, and 100 mTorr, and additionally at 50 mTorr for 1000 and 2000 V. Numerical results are given for a parallel plate oxygen discharge using a planar 1D3v (1 spatial dimension, 3 velocity components) particle-in-cell (PIC) code. New interesting phenomena are found for the case in which an EP edge does not exist. This 1-region case has not previously been investigated in detail, either numerically or analytically. In particular, attachment in the sheaths is important, and the central electron density n{sub e0} is depressed below the density n{sub esh} at the sheath edge. The sheath oscillations also extend into the EN core, creating an edge region lying within the sheath and not characterized by the standard diffusion in an EN plasma. An analytical model is developed using minimal inputs from the PIC results, and compared to the PIC results for a base case at V{sub rf}=500 V and 50 mTorr, showing good agreement. Selected comparisons are made at the other voltages and pressures. A self-consistent model is also developed and compared to the PIC results, giving reasonable agreement.

  15. Chiral gap effect in curved space

    E-Print Network [OSTI]

    Antonino Flachi; Kenji Fukushima

    2014-06-25T23:59:59.000Z

    We discuss a new type of QCD phenomenon induced in curved space. In the QCD vacuum a mass gap of Dirac fermions is attributed to the spontaneous breaking of chiral symmetry. If the curvature is positive large, the chiral condensate melts but a chiral invariant mass gap can still remain, which we name the chiral gap effect in curved space. This leads to decoupling of quark deconfinement which implies a view of black holes surrounded by a first-order QCD phase transition.

  16. Gap between active and passive solar heating

    SciTech Connect (OSTI)

    Balcomb, J.D.

    1985-01-01T23:59:59.000Z

    The gap between active and passive solar could hardly be wider. The reasons for this are discussed and advantages to narrowing the gap are analyzed. Ten years of experience in both active and passive systems are reviewed, including costs, frequent problems, performance prediction, performance modeling, monitoring, and cooling concerns. Trends are analyzed, both for solar space heating and for service water heating. A tendency for the active and passive technologies to be converging is observed. Several recommendations for narrowing the gap are presented.

  17. Robotic end gripper with a band member to engage object

    DOE Patents [OSTI]

    Pollard, R.E.; Robinson, S.C.; Thompson, W.F.; Couture, S.A.; Sutton, B.J.

    1994-05-10T23:59:59.000Z

    An end effector for use with robotic arms and like devices is described that utilizes a flexible band to draw an object against an anvil having a concave surface. One typical convex surface is created by a V-block, with an apex of the V being centrally located. If an object to be grasped is fragile, the contour of the concave surface closely matches the surface of the object. Typically the movement of the band is effected by a linear actuator, with the anvil remaining fixed relative to a support base. Several embodiments are described that utilize variations in drawing the band toward the anvil, with one of these embodiments described in detail in the form of a fabricated unit. One embodiment includes a cover element that can be moved over an object after the grasping thereof, with this cover potentially serving various functions. Movement of the cover can be effected with a second linear actuator. 8 figures.

  18. Robotic end gripper with a band member to engage object

    DOE Patents [OSTI]

    Pollard, Roy E. (Maryville, TN); Robinson, Samuel C. (Knoxville, TN); Thompson, William F. (Oak Ridge, TN); Couture, Scott A. (Knoxville, TN); Sutton, Bill J. (Powell, TN)

    1994-01-01T23:59:59.000Z

    An end effector for use with robotic arms and like devices that utilizes a flexible band to draw an object against an anvil having a concave surface. One typical convex surface is created by a V-block, with an apex of the V being centrally located. If an object to be grasped is fragile, the contour of the concave surface closely matches the surface of the object. Typically the movement of the band is effected by a linear actuator, with the anvil remaining fixed relative to a support base. Several embodiments are described that utilize variations in drawing the band toward the anvil, with one of these embodiments described in detail in the form of a fabricated unit. One embodiment includes a cover element that can be moved over an object after the grasping thereof, with this cover potentially serving various functions. Movement of the cover can be effected with a second linear actuator.

  19. FAQS Gap Analysis Qualification Card – Radiation Protection

    Broader source: Energy.gov [DOE]

    Functional Area Qualification Standard Gap Analysis Qualification Cards outline the differences between the last and latest version of the FAQ Standard.

  20. FAQS Gap Analysis Qualification Card – Mechanical Systems

    Broader source: Energy.gov [DOE]

    Functional Area Qualification Standard Gap Analysis Qualification Cards outline the differences between the last and latest version of the FAQ Standard.

  1. FAQS Gap Analysis Qualification Card – Environmental Restoration

    Broader source: Energy.gov [DOE]

    Functional Area Qualification Standard Gap Analysis Qualification Cards outline the differences between the last and latest version of the FAQ Standard.

  2. Undecidability of the Spectral Gap (short version)

    E-Print Network [OSTI]

    Cubitt, Toby; Wolf, Michael M

    2015-01-01T23:59:59.000Z

    The spectral gap -- the difference in energy between the ground state and the first excited state -- is one of the most important properties of a quantum many-body system. Quantum phase transitions occur when the spectral gap vanishes and the system becomes critical. Much of physics is concerned with understanding the phase diagrams of quantum systems, and some of the most challenging and long-standing open problems in theoretical physics concern the spectral gap, such as the Haldane conjecture that the Heisenberg chain is gapped for integer spin, proving existence of a gapped topological spin liquid phase, or the Yang-Mills gap conjecture (one of the Millennium Prize problems). These problems are all particular cases of the general spectral gap problem: Given a quantum many-body Hamiltonian, is the system it describes gapped or gapless? Here we show that this problem is undecidable, in the same sense as the Halting Problem was proven to be undecidable by Turing. A consequence of this is that the spectral gap...

  3. Undecidability of the Spectral Gap (short version)

    E-Print Network [OSTI]

    Toby Cubitt; David Perez-Garcia; Michael M. Wolf

    2015-02-13T23:59:59.000Z

    The spectral gap -- the difference in energy between the ground state and the first excited state -- is one of the most important properties of a quantum many-body system. Quantum phase transitions occur when the spectral gap vanishes and the system becomes critical. Much of physics is concerned with understanding the phase diagrams of quantum systems, and some of the most challenging and long-standing open problems in theoretical physics concern the spectral gap, such as the Haldane conjecture that the Heisenberg chain is gapped for integer spin, proving existence of a gapped topological spin liquid phase, or the Yang-Mills gap conjecture (one of the Millennium Prize problems). These problems are all particular cases of the general spectral gap problem: Given a quantum many-body Hamiltonian, is the system it describes gapped or gapless? Here we show that this problem is undecidable, in the same sense as the Halting Problem was proven to be undecidable by Turing. A consequence of this is that the spectral gap of certain quantum many-body Hamiltonians is not determined by the axioms of mathematics, much as Goedels incompleteness theorem implies that certain theorems are mathematically unprovable. We extend these results to prove undecidability of other low temperature properties, such as correlation functions. The proof hinges on simple quantum many-body models that exhibit highly unusual physics in the thermodynamic limit.

  4. FAQS Gap Analysis Qualification Card – Criticality Safety

    Broader source: Energy.gov [DOE]

    Functional Area Qualification Standard Gap Analysis Qualification Cards outline the differences between the last and latest version of the FAQ Standard.

  5. FAQS Gap Analysis Qualification Card – Construction Management

    Broader source: Energy.gov [DOE]

    Functional Area Qualification Standard Gap Analysis Qualification Cards outline the differences between the last and latest version of the FAQ Standard.

  6. The refractive index and electronic gap of water and ice increase with increasing pressure

    E-Print Network [OSTI]

    Pan, Ding; Galli, Giulia

    2014-01-01T23:59:59.000Z

    Determining the electronic and dielectric properties of water at high pressure and temperature is an essential prerequisite to understand the physical and chemical properties of aqueous environments under supercritical conditions, e.g. in the Earth interior. However optical measurements of compressed ice and water remain challenging and it has been common practice to assume that their band gap is inversely correlated to the measured refractive index, consistent with observations reported for hundreds of materials. Here we report ab initio molecular dynamics and electronic structure calculations showing that both the refractive index and the electronic gap of water and ice increase with pressure, at least up to 30 GPa. Subtle electronic effects, related to the nature of interband transitions and band edge localization under pressure, are responsible for this apparently anomalous behavior.

  7. Band offsets of n-type electron-selective contacts on cuprous oxide (Cu[subscript 2]O) for photovoltaics

    E-Print Network [OSTI]

    Brandt, Riley E.

    The development of cuprous oxide (Cu [subscript 2]O) photovoltaics (PVs) is limited by low device open-circuit voltages. A strong contributing factor to this underperformance is the conduction-band offset between Cu ...

  8. Tetracene air-gap single-crystal field-effect transistors Yu Xia, Vivek Kalihari, and C. Daniel Frisbiea

    E-Print Network [OSTI]

    Rogers, John A.

    Tetracene air-gap single-crystal field-effect transistors Yu Xia, Vivek Kalihari, and C. Daniel FETs utilizing an air or vacuum gap as the gate dielectric. The linear mobility of the device can be as high as 1.6 cm2 /V s in air, with a subthreshold slope lower than 0.5 V nF/decade cm2 . By changing

  9. Detection of DNA Hybridization Using the Near-Infrared Band-Gap

    E-Print Network [OSTI]

    Allen, Jont

    shift of 2 meV, with a detection sensitivity of 6 nM. The energy shift is modeled by correlating in the solution- based systems, is advantageous due to the sensitivity and selectivity of the technique.14 absorption of blood and tissue17-19 and the low auto- fluorescence of cells20 in the nIR. Furthermore, SWNTs

  10. Photonic band gap airbridge microcavity resonances in GaAs/AlxOy waveguides

    E-Print Network [OSTI]

    Fan, Shanhui

    -dielectric-contrast GaAs/AlxOy III­V compound semiconductor structure. The photonic crystal is defined by a regularly of optical states will be modified and quantized by such a cavity. Typical semiconductor optical cavities measurements of a one- dimensional PBG air-bridge optical microcavity are pre- sented here. A schematic

  11. Alternative Wide-Band-Gap Materials for Gamma-Ray Spectroscopy

    E-Print Network [OSTI]

    He, Zhong

    Engineering and Radiological Sciences) in The University of Michigan 2013 Doctoral Committee: Professor Zhong emotionally, physically, spiritually, and intellectually through every moment of my graduate school career, the Orion group would not be successful without the great work of his graduate students. It has been a truly

  12. Tunable micro-cavities in photonic band-gap yarns and optical fibers

    E-Print Network [OSTI]

    Benoit, Gilles, Ph. D. Massachusetts Institute of Technology

    2006-01-01T23:59:59.000Z

    The vision behind this work is the fabrication of high performance innovative fiber-based optical components over kilometer length-scales. The optical properties of these fibers derive from their multilayer dielectric ...

  13. A Novel Synthesis Method for Designing Electromagnetic Band Gap (EBG) Structures in Packaged Mixed Signal Systems

    E-Print Network [OSTI]

    Swaminathan, Madhavan

    on a periodically patterned power/ground plane. CPA-Method gives a final dimension of EBG structure for a desired. PLM calculates isolation level of an EBG structure based on the transmitted power. The proposed's mixed-signal systems are very sensitive to power/ground noise. For high-speed systems, it has been

  14. Control of ionization processes in high band gap materials via tailored

    E-Print Network [OSTI]

    Kassel, Universität

    on Ultrafast Electron Dynamics in Femtosecond Optical Breakdown of Dielectrics," Phys. Rev. Lett. 83, 5182­5182

  15. Final Report: Laser-Material Interactions Relevant to Analytic Spectroscopy of Wide Band Gap Materials

    SciTech Connect (OSTI)

    Dickinson, J. T. [Washington State University] [Washington State University

    2014-04-05T23:59:59.000Z

    We summarize our studies aimed at developing an understanding of the underlying physics and chemistry in terms of laser materials interactions relevant to laser-based sampling and chemical analysis of wide bandgap materials. This work focused on the determination of mechanisms for the emission of electrons, ions, atoms, and molecules from laser irradiation of surfaces. We determined the important role of defects on these emissions, the thermal, chemical, and physical interactions responsible for matrix effects and mass-dependent transport/detection. This work supported development of new techniques and technology for the determination of trace elements contained such as nuclear waste materials.

  16. Bispyridinium-phenylene-based copolymers: low band gap n-type alternating copolymers

    E-Print Network [OSTI]

    Swager, Timothy Manning

    Bispyridinium-phenylene-based conjugated donor–acceptor copolymers were synthesized by a Stille cross-coupling and cyclization sequence. These polyelectrolytes are freely soluble in organic solvents and display broad optical ...

  17. Comment on "Direct space-time observation of pulse tunneling in an electromagnetic band gap"

    E-Print Network [OSTI]

    G. Nimtz; A. A. Stahlhofen

    2008-01-13T23:59:59.000Z

    The investigation presented by Doiron, Hache, and Winful [Phys. Rev. A 76, 023823 (2007)] is not valid for the tunneling process as claimed in the paper.

  18. Second harmonic generation from direct band gap quantum dots pumped by femtosecond laser pulses

    SciTech Connect (OSTI)

    Liu, Liwei, E-mail: liulw@cust.edu.cn; Wang, Yue; Hu, Siyi; Ren, Yu; Huang, Chen [School of Science, Changchun University of Science and Technology, Changchun, Jilin 130022, People's Republic of China and International Joint Research Center for Nanophotonics and Biophotonics, Changchun University of Science and Technology, Changchun, Jilin 130022 (China)

    2014-02-21T23:59:59.000Z

    We report on nonlinear optical experiments performed on Cu{sub 2}S quantum dots (QDs) pumped by femtosecond laser pulses. We conduct a theoretical simulation and experiments to determine their second harmonic generation characteristics. Furthermore, we demonstrate that the QDs have a second harmonic generation conversion efficiency of up to 76%. Our studies suggest that these Cu{sub 2}S QDs can be used for solar cells, bioimaging, biosensing, and electric detection.

  19. InAlAs EPITAXIAL GROWTH FOR WIDE BAND GAP SOLAR CELLS Marina S. Leite

    E-Print Network [OSTI]

    Atwater, Harry

    concentrator cells made of metamorphic InGaP/GaAs/InGaAs can achieve > 41 % by using metamorphic epitaxial

  20. Final Report: Tunable Narrow Band Gap Absorbers For Ultra High Efficiency Solar Cells

    SciTech Connect (OSTI)

    Bedair, Salah M. [NCSU; Hauser, John R. [NCSU; Elmasry, Nadia [NCSU; Colter, Peter C. [NCSU; Bradshaw, G. [NCSU; Carlin, C. Z. [NCSU; Samberg, J. [NCSU; Edmonson, Kenneth [Spectrolab

    2012-07-31T23:59:59.000Z

    We report on a joint research program between NCSU and Spectrolab to develop an upright multijunction solar cell structure with a potential efficiency exceeding the current record of 41.6% reported by Spectrolab. The record efficiency Ge/GaAs/InGaP triple junction cell structure is handicapped by the fact that the current generated by the Ge cell is much higher than that of both the middle and top cells. We carried out a modification of the record cell structure that will keep the lattice matched condition and allow better matching of the current generated by each cell. We used the concept of strain balanced strained layer superlattices (SLS), inserted in the i-layer, to reduce the bandgap of the middle cell without violating the desirable lattice matched condition. For the middle GaAs cell, we have demonstrated an n-GaAs/i-(InGaAs/GaAsP)/p-GaAs structure, where the InxGa1-xAs/GaAs1-yPy SLS is grown lattice matched to GaAs and with reduced bandgap from 1.43 eV to 1.2 eV, depending upon the values of x and y.

  1. Nature of the Band Gap and Origin of the Electro-/Photo-Activity...

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

    oxidematerials in photocatalysis and solar applications. Citation: Qiao L, HY Xiao, HM Meyer, JN Sun, CM Rouleau, AA Puretzky, DB Geohegan, IN Ivanov, M Yoon, WJ Weber, and MD...

  2. A New Gap-Opening Mechanism in a Triple-Band Metal

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del(ANL-IN-03-032) -Less isNFebruaryOctober 2, AlgeriaQ1A Month to RememberEIA'sNewAA

  3. A New Gap-Opening Mechanism in a Triple-Band Metal

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del(ANL-IN-03-032) -Less isNFebruaryOctober 2, AlgeriaQ1A Month to RememberEIA'sNewAAA

  4. A New Gap-Opening Mechanism in a Triple-Band Metal

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del(ANL-IN-03-032) -Less isNFebruaryOctober 2, AlgeriaQ1A Month to RememberEIA'sNewAAAA

  5. A New Gap-Opening Mechanism in a Triple-Band Metal

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del(ANL-IN-03-032) -Less isNFebruaryOctober 2, AlgeriaQ1A Month to

  6. A New Gap-Opening Mechanism in a Triple-Band Metal

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItemResearch >InternshipDepartmentNeutrino-Induced Charged-CurrentN N U A L R EA New

  7. Gap Assessment (FY 13 Update)

    SciTech Connect (OSTI)

    Getman, Dan

    2013-09-30T23:59:59.000Z

    To help guide its future data collection efforts, The DOE GTO funded a data gap analysis in FY2012 to identify high potential hydrothermal areas where critical data are needed. This analysis was updated in FY2013 and the resulting datasets are represented by this metadata. The original process was published in FY 2012 and is available here: https://pangea.stanford.edu/ERE/db/GeoConf/papers/SGW/2013/Esposito.pdf Though there are many types of data that can be used for hydrothermal exploration, five types of exploration data were targeted for this analysis. These data types were selected for their regional reconnaissance potential, and include many of the primary exploration techniques currently used by the geothermal industry. The data types include: 1. well data 2. geologic maps 3. fault maps 4. geochemistry data 5. geophysical data To determine data coverage, metadata for exploration data (including data type, data status, and coverage information) were collected and catalogued from nodes on the National Geothermal Data System (NGDS). It is the intention of this analysis that the data be updated from this source in a semi-automated fashion as new datasets are added to the NGDS nodes. In addition to this upload, an online tool was developed to allow all geothermal data providers to access this assessment and to directly add metadata themselves and view the results of the analysis via maps of data coverage in Geothermal Prospector (http://maps.nrel.gov/gt_prospector). A grid of the contiguous U.S. was created with 88,000 10-km by 10-km grid cells, and each cell was populated with the status of data availability corresponding to the five data types. Using these five data coverage maps and the USGS Resource Potential Map, sites were identified for future data collection efforts. These sites signify both that the USGS has indicated high favorability of occurrence of geothermal resources and that data gaps exist. The uploaded data are contained in two data files for each data category. The first file contains the grid and is in the SHP file format (shape file.) Each populated grid cell represents a 10k area within which data is known to exist. The second file is a CSV (comma separated value) file that contains all of the individual layers that intersected with the grid. This CSV can be joined with the map to retrieve a list of datasets that are available at any given site. The attributes in the CSV include: 1. grid_id : The id of the grid cell that the data intersects with 2. title: This represents the name of the WFS service that intersected with this grid cell 3. abstract: This represents the description of the WFS service that intersected with this grid cell 4. gap_type: This represents the category of data availability that these data fall within. As the current processing is pulling data from NGDS, this category universally represents data that are available in the NGDS and are ready for acquisition for analytic purposes. 5. proprietary_type: Whether the data are considered proprietary 6. service_type: The type of service 7. base_url: The service URL

  8. Drop short control of electrode gap

    DOE Patents [OSTI]

    Fisher, Robert W. (Albuquerque, NM); Maroone, James P. (Albuquerque, NM); Tipping, Donald W. (Albuquerque, NM); Zanner, Frank J. (Sandia Park, NM)

    1986-01-01T23:59:59.000Z

    During vacuum consumable arc remelting the electrode gap between a consumable electrode and a pool of molten metal is difficult to control. The present invention monitors drop shorts by detecting a decrease in the voltage between the consumable electrode and molten pool. The drop shorts and their associated voltage reductions occur as repetitive pulses which are closely correlated to the electrode gap. Thus, the method and apparatus of the present invention controls electrode gap based upon drop shorts detected from the monitored anode-cathode voltage. The number of drop shorts are accumulated, and each time the number of drop shorts reach a predetermined number, the average period between drop shorts is calculated from this predetermined number and the time in which this number is accumulated. This average drop short period is used in a drop short period electrode gap model which determines the actual electrode gap from the drop short. The actual electrode gap is then compared with a desired electrode gap which is selected to produce optimum operating conditions and the velocity of the consumable error is varied based upon the gap error. The consumable electrode is driven according to any prior art system at this velocity. In the preferred embodiment, a microprocessor system is utilized to perform the necessary calculations and further to monitor the duration of each drop short. If any drop short exceeds a preset duration period, the consumable electrode is rapidly retracted a predetermined distance to prevent bonding of the consumable electrode to the molten remelt.

  9. Electronic band structure and optical properties of the cubic, Sc, Y and La hydride systems

    SciTech Connect (OSTI)

    Peterman, D.J.

    1980-01-01T23:59:59.000Z

    Electronic band structure calculations are used to interpret the optical spectra of the cubic Sc, Y and La hydride systems. Self-consistent band calculations of ScH/sub 2/ and YH/sub 2/ were carried out. The respective joint densities of states are computed and compared to the dielectric functions determined from the optical measurements. Additional calculations were performed in which the Fermi level or band gap energies are rigidly shifted by a small energy increment. These calculations are then used to simulate the derivative structure in thermomodulation spectra and relate the origin of experimental interband features to the calculated energy bands. While good systematic agreement is obtained for several spectral features, the origin of low-energy interband transitions in YH/sub 2/ cannot be explained by these calculated bands. A lattice-size-dependent premature occupation of octahedral sites by hydrogen atoms in the fcc metal lattice is suggested to account for this discrepancy. Various non-self-consistent calculations are used to examine the effect of such a premature occupation. Measurements of the optical absorptivity of LaH/sub x/ with 1.6 < x < 2.9 are presented which, as expected, indicate a more premature occupation of the octahedral sites in the larger LaH/sub 2/ lattice. These experimental results also suggest that, in contrast to recent calculations, LaH/sub 3/ is a small-band-gap semiconductor.

  10. Bipolar thermoelectric devices

    E-Print Network [OSTI]

    Pipe, Kevin P. (Kevin Patrick), 1976-

    2004-01-01T23:59:59.000Z

    The work presented here is a theoretical and experimental study of heat production and transport in bipolar electrical devices, with detailed treatment of thermoelectric effects. Both homojunction and heterojunction devices ...

  11. array devices high-dynamic: Topics by E-print Network

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

    WATT X-BAND POWER COMBINING ARRAY USING COUPLED VCOs Engineering Websites Summary: single solid state devices 11-51, Quasi-optical arrays achieve power combination through the...

  12. Organic photosensitive devices

    DOE Patents [OSTI]

    Rand, Barry P; Forrest, Stephen R

    2013-11-26T23:59:59.000Z

    The present invention generally relates to organic photosensitive optoelectronic devices. More specifically, it is directed to organic photosensitive optoelectronic devices having a photoactive organic region containing encapsulated nanoparticles that exhibit plasmon resonances. An enhancement of the incident optical field is achieved via surface plasmon polariton resonances. This enhancement increases the absorption of incident light, leading to a more efficient device.

  13. Articulating feedstock delivery device

    DOE Patents [OSTI]

    Jordan, Kevin

    2013-11-05T23:59:59.000Z

    A fully articulable feedstock delivery device that is designed to operate at pressure and temperature extremes. The device incorporates an articulating ball assembly which allows for more accurate delivery of the feedstock to a target location. The device is suitable for a variety of applications including, but not limited to, delivery of feedstock to a high-pressure reaction chamber or process zone.

  14. Amorphous silicon photovoltaic devices

    DOE Patents [OSTI]

    Carlson, David E.; Lin, Guang H.; Ganguly, Gautam

    2004-08-31T23:59:59.000Z

    This invention is a photovoltaic device comprising an intrinsic or i-layer of amorphous silicon and where the photovoltaic device is more efficient at converting light energy to electric energy at high operating temperatures than at low operating temperatures. The photovoltaic devices of this invention are suitable for use in high temperature operating environments.

  15. INFORMATION DEVICES AND

    E-Print Network [OSTI]

    Mottram, Nigel

    to access or hold sensitive, confidential or personal information on mobile devices, such as laptopsPROTECTION OF INFORMATION HELD ON MOBILE DEVICES AND ENCRYPTION POLICY (V3.5) the place of useful;Protection of Information Held on Mobile Devices and Encryption Policy (v3.5) Page 1 Table of Contents 1

  16. Portable data collection device

    DOE Patents [OSTI]

    French, Patrick D. (Aurora, CO)

    1996-01-01T23:59:59.000Z

    The present invention provides a portable data collection device that has a variety of sensors that are interchangeable with a variety of input ports in the device. The various sensors include a data identification feature that provides information to the device regarding the type of physical data produced by each sensor and therefore the type of sensor itself. The data identification feature enables the device to locate the input port where the sensor is connected and self adjust when a sensor is removed or replaced. The device is able to collect physical data, whether or not a function of a time.

  17. Unitary lens semiconductor device

    DOE Patents [OSTI]

    Lear, Kevin L. (Albuquerque, NM)

    1997-01-01T23:59:59.000Z

    A unitary lens semiconductor device and method. The unitary lens semiconductor device is provided with at least one semiconductor layer having a composition varying in the growth direction for unitarily forming one or more lenses in the semiconductor layer. Unitary lens semiconductor devices may be formed as light-processing devices such as microlenses, and as light-active devices such as light-emitting diodes, photodetectors, resonant-cavity light-emitting diodes, vertical-cavity surface-emitting lasers, and resonant cavity photodetectors.

  18. PHOTONICS and DEVICE MICROFABRICATION

    E-Print Network [OSTI]

    Mottram, Nigel

    in the University. Our key objective is to bridge the gap between academic research and industrial application that are in demand in the semiconductor and optoelectronics industries and other high- technology manufacturing

  19. Active terahertz metamaterial devices

    DOE Patents [OSTI]

    Chen, Houtong (Los Alamos, NM); Padilla, Willie John (Newton, MA); Averitt, Richard Douglas (Newton, MA); O'Hara, John F. (Los Alamos, NM); Lee, Mark (Albuquerque, NM)

    2010-11-02T23:59:59.000Z

    Metamaterial structures are taught which provide for the modulation of terahertz frequency signals. Each element within an array of metamaterial (MM) elements comprises multiple loops and at least one gap. The MM elements may comprise resonators with conductive loops and insulated gaps, or the inverse in which insulated loops are present with conductive gaps; each providing useful transmissive control properties. The metamaterial elements are fabricated on a semiconducting substrate configured with a means of enhancing or depleting electrons from near the gaps of the MM elements. An on to off transmissivity ratio of about 0.5 is achieved with this approach. Embodiments are described in which the MM elements incorporated within a Quantum Cascade Laser (QCL) to provide surface emitting (SE) properties.

  20. Engine piston having an insulating air gap

    DOE Patents [OSTI]

    Jarrett, Mark Wayne (Washington, IL); Hunold,Brent Michael (Apex, NC)

    2010-02-02T23:59:59.000Z

    A piston for an internal combustion engine has an upper crown with a top and a bottom surface, and a lower crown with a top and a bottom surface. The upper crown and the lower crown are fixedly attached to each other using welds, with the bottom surface of the upper crown and the top surface of the lower crown forming a mating surface. The piston also has at least one centrally located air gap formed on the mating surface. The air gap is sealed to prevent substantial airflow into or out of the air gap.

  1. Chiral gap effect in curved space

    E-Print Network [OSTI]

    Antonino Flachi; Kenji Fukushima

    2015-05-29T23:59:59.000Z

    We discuss a new type of QCD phenomenon induced in curved space. In the QCD vacuum, a mass-gap of Dirac fermions is attributed to the spontaneous breaking of chiral symmetry. If the curvature is positive large, the chiral condensate melts but a chiral invariant mass-gap can still remain, which we name the chiral gap effect in curved space. This leads to decoupling of quark deconfinement which implies a view of black holes surrounded by a first-order QCD phase transition.

  2. Effect of Ga content on defect states in CuIn1xGaxSe2 photovoltaic devices

    E-Print Network [OSTI]

    Rockett, Angus

    gaps for single junction solar cells expected to be around 1.4 eV.2 This corresponds to a Ga fraction x gap of CuIn1 xGaxSe2 CIGS . This technique is sensitive to opti- cal absorption in the active layer CIGS. Photovoltaic devices based on thin polycrystalline CIGS absorbers have achieved record lab

  3. Tamper-indicating device having a glass body

    DOE Patents [OSTI]

    Johnston, Roger G. (Los Alamos, NM); Garcia, Anthony R. E. (Espanola, NM)

    2003-04-29T23:59:59.000Z

    A tamper-indicating device is described. The device has a first glass body member and a second glass body member that are attached to each other through a hasp. The glass body members of the device can be tempered. The body members can be configured with hollow volumes into which powders, microparticles, liquids, gels, or combinations thereof are sealed. The choice, the amount, and the location of these materials can produce a visible, band pattern to provide each body member with a unique fingerprint identifier, which makes it extremely difficult to repair or replace once it is damaged in order to avoid tamper detection.

  4. Organic electronic devices using phthalimide compounds

    DOE Patents [OSTI]

    Hassan, Azad M.; Thompson, Mark E.

    2012-10-23T23:59:59.000Z

    Organic electronic devices comprising a phthalimide compound. The phthalimide compounds disclosed herein are electron transporters with large HOMO-LUMO gaps, high triplet energies, large reduction potentials, and/or thermal and chemical stability. As such, these phthalimide compounds are suitable for use in any of various organic electronic devices, such as OLEDs and solar cells. In an OLED, the phthalimide compounds may serve various functions, such as a host in the emissive layer, as a hole blocking material, or as an electron transport material. In a solar cell, the phthalimide compounds may serve various functions, such as an exciton blocking material. Various examples of phthalimide compounds which may be suitable for use in the present invention are disclosed.

  5. Organic electronic devices using phthalimide compounds

    DOE Patents [OSTI]

    Hassan, Azad M.; Thompson, Mark E.

    2010-09-07T23:59:59.000Z

    Organic electronic devices comprising a phthalimide compound. The phthalimide compounds disclosed herein are electron transporters with large HOMO-LUMO gaps, high triplet energies, large reduction potentials, and/or thermal and chemical stability. As such, these phthalimide compounds are suitable for use in any of various organic electronic devices, such as OLEDs and solar cells. In an OLED, the phthalimide compounds may serve various functions, such as a host in the emissive layer, as a hole blocking material, or as an electron transport material. In a solar cell, the phthalimide compounds may serve various functions, such as an exciton blocking material. Various examples of phthalimide compounds which may be suitable for use in the present invention are disclosed.

  6. Organic electronic devices using phthalimide compounds

    DOE Patents [OSTI]

    Hassan, Azad M.; Thompson, Mark E.

    2013-03-19T23:59:59.000Z

    Organic electronic devices comprising a phthalimide compound. The phthalimide compounds disclosed herein are electron transporters with large HOMO-LUMO gaps, high triplet energies, large reduction potentials, and/or thermal and chemical stability. As such, these phthalimide compounds are suitable for use in any of various organic electronic devices, such as OLEDs and solar cells. In an OLED, the phthalimide compounds may serve various functions, such as a host in the emissive layer, as a hole blocking material, or as an electron transport material. In a solar cell, the phthalimide compounds may serve various functions, such as an exciton blocking material. Various examples of phthalimide compounds which may be suitable for use in the present invention are disclosed.

  7. Are We Closing the School Discipline Gap?

    E-Print Network [OSTI]

    Losen, Daniel; Hodson, Cheri; Keith II, Michael A; Morrison, Katrina; Belway, Shakti

    2015-01-01T23:59:59.000Z

    D.J. , (Ed). Closing the School Discipline Gap: EquitableBooth, E.A. (2011). Breaking schools’ rules: A statewidestudy of how school discipline relates to students’ success

  8. Columbia River Component Data Gap Analysis

    SciTech Connect (OSTI)

    L. C. Hulstrom

    2007-10-23T23:59:59.000Z

    This Data Gap Analysis report documents the results of a study conducted by Washington Closure Hanford (WCH) to compile and reivew the currently available surface water and sediment data for the Columbia River near and downstream of the Hanford Site. This Data Gap Analysis study was conducted to review the adequacy of the existing surface water and sediment data set from the Columbia River, with specific reference to the use of the data in future site characterization and screening level risk assessments.

  9. Barrier breaching device

    DOE Patents [OSTI]

    Honodel, C.A.

    1983-06-01T23:59:59.000Z

    A barrier breaching device that is designed primarily for opening holes in interior walls of buildings uses detonating fuse for explosive force. The fuse acts as the ribs or spokes of an umbrella-like device that may be opened up to form a cone. The cone is placed against the wall so that detonating fuse that rings the base of the device and which is ignited by the spoke-like fuses serves to cut a circular hole in the wall.

  10. Barrier breaching device

    DOE Patents [OSTI]

    Honodel, Charles A. (Tracy, CA)

    1985-01-01T23:59:59.000Z

    A barrier breaching device that is designed primarily for opening holes in interior walls of buildings uses detonating fuse for explosive force. The fuse acts as the ribs or spokes of an umbrella-like device that may be opened up to form a cone. The cone is placed against the wall so that detonating fuse that rings the base of the device and which is ignited by the spoke-like fuses serves to cut a circular hole in the wall.

  11. Code Gaps and Future Research Needs of Combustion Safety: Building...

    Energy Savers [EERE]

    Code Gaps and Future Research Needs of Combustion Safety: Building America Expert Meeting Update Code Gaps and Future Research Needs of Combustion Safety: Building America Expert...

  12. Summary of Gaps and Barriers for Implementing Residential Building...

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

    Gaps and Barriers for Implementing Residential Building Energy Efficiency Strategies Summary of Gaps and Barriers for Implementing Residential Building Energy Efficiency Strategies...

  13. NWChem: Bridging the Gap Between Experimental and Computational...

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

    NWChem: Bridging the Gap Between Experimental and Computational Chemistry NWChem: Bridging the Gap Between Experimental and Computational Chemistry Intel recently interviewed...

  14. antiparticle spectrometer gaps: Topics by E-print Network

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

    Next Page Last Page Topic Index 1 The General Antiparticle Spectrometer (GAPS) - Hunt for dark matter using low-energy antideuterons CERN Preprints Summary: The GAPS experiment is...

  15. CHP: Connecting the Gap between Markets and Utility Interconnection...

    Office of Environmental Management (EM)

    CHP: Connecting the Gap between Markets and Utility Interconnection and Tariff Practices, 2006 CHP: Connecting the Gap between Markets and Utility Interconnection and Tariff...

  16. Interconnected semiconductor devices

    DOE Patents [OSTI]

    Grimmer, Derrick P. (White Bear Lake, MN); Paulson, Kenneth R. (North St. Paul, MN); Gilbert, James R. (St. Paul, MN)

    1990-10-23T23:59:59.000Z

    Semiconductor layer and conductive layer formed on a flexible substrate, divided into individual devices and interconnected with one another in series by interconnection layers and penetrating terminals.

  17. High efficiency photovoltaic device

    DOE Patents [OSTI]

    Guha, Subhendu (Troy, MI); Yang, Chi C. (Troy, MI); Xu, Xi Xiang (Findlay, OH)

    1999-11-02T23:59:59.000Z

    An N-I-P type photovoltaic device includes a multi-layered body of N-doped semiconductor material which has an amorphous, N doped layer in contact with the amorphous body of intrinsic semiconductor material, and a microcrystalline, N doped layer overlying the amorphous, N doped material. A tandem device comprising stacked N-I-P cells may further include a second amorphous, N doped layer interposed between the microcrystalline, N doped layer and a microcrystalline P doped layer. Photovoltaic devices thus configured manifest improved performance, particularly when configured as tandem devices.

  18. Valence band hybridization in N-rich GaN1-xAsx alloys

    SciTech Connect (OSTI)

    Wu, J.; Walukiewicz, W.; Yu, K.M.; Denlinger, J.D.; Shan, W.; Ager III, J.W.; Kimura, A.; Tang, H.F.; Kuech, T.F.

    2004-05-04T23:59:59.000Z

    We have used photo-modulated transmission and optical absorption spectroscopies to measure the composition dependence of interband optical transitions in N-rich GaN{sub 1-x}As{sub x} alloys with x up to 0.06. The direct bandgap gradually decreases as x increases. In the dilute x limit, the observed band gap approaches 2.8 eV; this limiting value is attributed to a transition between the As localized level, which has been previously observed in As-doped GaN at 0.6 eV above the valence band maximum in As-doped GaN, and the conduction band minimum. The structure of the valence band of GaN{sub 1-x}As{sub x} is explained by the hybridization of the localized As states with the extended valence band states of GaN matrix. The hybridization is directly confirmed by soft x-ray emission experiments. To describe the electronic structure of the GaN{sub 1-x}As{sub x} alloys in the entire composition range a linear interpolation is used to combine the effects of valence band hybridization in N-rich alloys with conduction band anticrossing in As-rich alloys.

  19. Mobile Device Management Android Device Enrollment

    E-Print Network [OSTI]

    to manage your device. c. Enter your password. #12;d. Accept the Terms and Conditions e. You have completed. 2. Get Touchdown from Google Play a. Open up the Google Play Store. b. Search for Touchdown. c. Use the application. #12;3. Get Citrix Mobile Connect from Google Play a. Open up the Google Play Store. b. Search

  20. Energy band modulation of graphane by hydrogen-vacancy chains: A first-principles study

    SciTech Connect (OSTI)

    Wu, Bi-Ru [Department of Natural science, Center for General Education, Chang Gung University, Kueishan 333, Taiwan, ROC (China); Yang, Chih-Kai, E-mail: ckyang@nccu.edu.tw [Graduate Institute of Applied Physics, National Chengchi University, Taipei 11605, Taiwan, ROC (China)

    2014-08-15T23:59:59.000Z

    We investigated a variety of configurations of hydrogen-vacancy chains in graphane by first-principles density functional calculation. We found that graphane with two zigzag H-vacancy chains segregated by one or more H chain is generally a nonmagnetic conductor or has a negligible band gap. However, the same structure is turned into a semiconductor and generates a magnetic moment if either one or both of the vacancy chains are blocked by isolated H atoms. If H-vacancy chains are continuously distributed, the structure is similar to a zigzag graphene nanoribbon embedded in graphane. It was also found that the embedded zigzag graphene nanoribbon is antiferromagnetic, and isolated H atoms left in the 2-chain nanoribbon can tune the band gap and generate net magnetic moments. Similar effects are also obtained if bare carbon atoms are present outside the nanoribbon. These results are useful for designing graphene-based nanoelectronic circuits.

  1. Magnetism and interaction-induced gap opening in graphene with vacancies or hydrogen adatoms: Quantum Monte Carlo study

    E-Print Network [OSTI]

    Ulybyshev, M V

    2015-01-01T23:59:59.000Z

    We study electronic properties of graphene with finite concentration of vacancies or other resonant scatterers by a straightforward lattice Quantum Monte Carlo calculations. Taking into account realistic long-range Coulomb interaction we calculate distribution of spin density associated to midgap states and demonstrate antiferromagnetic ordering. Energy gap are open due to the interaction effects, both in the bare graphene spectrum and in the vacancy/impurity bands. In the case of 5 % concentration of resonant scatterers the latter gap is estimated as 0.7 eV and 1.1 eV for graphene on boron nitride and freely suspended graphene, respectively.

  2. Magnetism and interaction-induced gap opening in graphene with vacancies or hydrogen adatoms: Quantum Monte Carlo study

    E-Print Network [OSTI]

    M. V. Ulybyshev; M. I. Katsnelson

    2015-02-04T23:59:59.000Z

    We study electronic properties of graphene with finite concentration of vacancies or other resonant scatterers by a straightforward lattice Quantum Monte Carlo calculations. Taking into account realistic long-range Coulomb interaction we calculate distribution of spin density associated to midgap states and demonstrate antiferromagnetic ordering. Energy gap are open due to the interaction effects, both in the bare graphene spectrum and in the vacancy/impurity bands. In the case of 5 % concentration of resonant scatterers the latter gap is estimated as 0.7 eV and 1.1 eV for graphene on boron nitride and freely suspended graphene, respectively.

  3. Magnetism and interaction-induced gap opening in graphene with vacancies or hydrogen adatoms: Quantum Monte Carlo study

    E-Print Network [OSTI]

    M. V. Ulybyshev; M. I. Katsnelson

    2015-05-22T23:59:59.000Z

    We study electronic properties of graphene with finite concentration of vacancies or other resonant scatterers by a straightforward lattice Quantum Monte Carlo calculations. Taking into account realistic long-range Coulomb interaction we calculate distribution of spin density associated to midgap states and demonstrate antiferromagnetic ordering. Energy gaps are open due to the interaction effects, both in the bare graphene spectrum and in the vacancy/impurity bands. In the case of 5 % concentration of resonant scatterers the latter gap is estimated as 0.7 eV and 1.1 eV for graphene on boron nitride and freely suspended graphene, respectively.

  4. Heterojunction band offsets and dipole formation at BaTiO{sub 3}/SrTiO{sub 3} interfaces

    SciTech Connect (OSTI)

    Balaz, Snjezana [Department of Physics and Astronomy, Youngstown State University, One University Plaza, Youngstown, Ohio 44555 (United States)] [Department of Physics and Astronomy, Youngstown State University, One University Plaza, Youngstown, Ohio 44555 (United States); Zeng, Zhaoquan [Department of Electrical and Computer Engineering, The Ohio State University, 205 Dreese Lab, 2015 Neil Ave., Columbus, Ohio 43210 (United States)] [Department of Electrical and Computer Engineering, The Ohio State University, 205 Dreese Lab, 2015 Neil Ave., Columbus, Ohio 43210 (United States); Brillson, Leonard J. [Department of Electrical and Computer Engineering, The Ohio State University, 205 Dreese Lab, 2015 Neil Ave., Columbus, Ohio 43210 (United States) [Department of Electrical and Computer Engineering, The Ohio State University, 205 Dreese Lab, 2015 Neil Ave., Columbus, Ohio 43210 (United States); Department of Physics, The Ohio State University, 191 West Woodruff, Columbus, Ohio 43210 (United States)

    2013-11-14T23:59:59.000Z

    We used a complement of photoemission and cathodoluminescence techniques to measure formation of the BaTiO{sub 3} (BTO) on SrTiO{sub 3} (STO) heterojunction band offset grown monolayer by monolayer by molecular beam epitaxy. X-ray photoemission spectroscopy (XPS) provided core level and valence band edge energies to monitor the valence band offset in-situ as the first few crystalline BTO monolayers formed on the STO substrate. Ultraviolet photoemission spectroscopy (UPS) measured Fermi level positions within the band gap, work functions, and ionization potentials of the growing BTO film. Depth-resolved cathodoluminescence spectroscopy measured energies and densities of interface states at the buried heterojunction. Kraut-based XPS heterojunction band offsets provided evidence for STO/BTO heterojunction linearity, i.e., commutativity and transitivity. In contrast, UPS and XPS revealed a large dipole associated either with local charge transfer or strain-induced polarization within the BTO epilayer.

  5. Capillary interconnect device

    DOE Patents [OSTI]

    Renzi, Ronald F

    2013-11-19T23:59:59.000Z

    An interconnecting device for connecting a plurality of first fluid-bearing conduits to a corresponding plurality of second fluid-bearing conduits thereby providing fluid communication between the first fluid-bearing conduits and the second fluid-bearing conduits. The device includes a manifold and one or two ferrule plates that are held by compressive axial forces.

  6. Bridging The Gap 2012 | ornl.gov

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

    Low-cost Nanomaterials for PV Devices Wireless Charging High Performance Mesoporus Titanium Oxide Anode Based Lithium Ion Batteries One-on-one technology discussion with...

  7. Device for cutting protrusions

    DOE Patents [OSTI]

    Bzorgi, Fariborz M. (Knoxville, TN)

    2011-07-05T23:59:59.000Z

    An apparatus for clipping a protrusion of material is provided. The protrusion may, for example, be a bolt head, a nut, a rivet, a weld bead, or a temporary assembly alignment tab protruding from a substrate surface of assembled components. The apparatus typically includes a cleaver having a cleaving edge and a cutting blade having a cutting edge. Generally, a mounting structure configured to confine the cleaver and the cutting blade and permit a range of relative movement between the cleaving edge and the cutting edge is provided. Also typically included is a power device coupled to the cutting blade. The power device is configured to move the cutting edge toward the cleaving edge. In some embodiments the power device is activated by a momentary switch. A retraction device is also generally provided, where the retraction device is configured to move the cutting edge away from the cleaving edge.

  8. Fluidic nanotubes and devices

    DOE Patents [OSTI]

    Yang, Peidong (El Cerrito, CA); He, Rongrui (El Cerrito, CA); Goldberger, Joshua (Berkeley, CA); Fan, Rong (El Cerrito, CA); Wu, Yiying (Albany, CA); Li, Deyu (Albany, CA); Majumdar, Arun (Orinda, CA)

    2010-01-10T23:59:59.000Z

    Fluidic nanotube devices are described in which a hydrophilic, non-carbon nanotube, has its ends fluidly coupled to reservoirs. Source and drain contacts are connected to opposing ends of the nanotube, or within each reservoir near the opening of the nanotube. The passage of molecular species can be sensed by measuring current flow (source-drain, ionic, or combination). The tube interior can be functionalized by joining binding molecules so that different molecular species can be sensed by detecting current changes. The nanotube may be a semiconductor, wherein a tubular transistor is formed. A gate electrode can be attached between source and drain to control current flow and ionic flow. By way of example an electrophoretic array embodiment is described, integrating MEMs switches. A variety of applications are described, such as: nanopores, nanocapillary devices, nanoelectrophoretic, DNA sequence detectors, immunosensors, thermoelectric devices, photonic devices, nanoscale fluidic bioseparators, imaging devices, and so forth.

  9. Fluidic nanotubes and devices

    DOE Patents [OSTI]

    Yang, Peidong (Berkeley, CA); He, Rongrui (El Cerrito, CA); Goldberger, Joshua (Berkeley, CA); Fan, Rong (El Cerrito, CA); Wu, Yiying (Albany, CA); Li, Deyu (Albany, CA); Majumdar, Arun (Orinda, CA)

    2008-04-08T23:59:59.000Z

    Fluidic nanotube devices are described in which a hydrophilic, non-carbon nanotube, has its ends fluidly coupled to reservoirs. Source and drain contacts are connected to opposing ends of the nanotube, or within each reservoir near the opening of the nanotube. The passage of molecular species can be sensed by measuring current flow (source-drain, ionic, or combination). The tube interior can be functionalized by joining binding molecules so that different molecular species can be sensed by detecting current changes. The nanotube may be a semiconductor, wherein a tubular transistor is formed. A gate electrode can be attached between source and drain to control current flow and ionic flow. By way of example an electrophoretic array embodiment is described, integrating MEMs switches. A variety of applications are described, such as: nanopores, nanocapillary devices, nanoelectrophoretic, DNA sequence detectors, immunosensors, thermoelectric devices, photonic devices, nanoscale fluidic bioseparators, imaging devices, and so forth.

  10. Planar electrochemical device assembly

    DOE Patents [OSTI]

    Jacobson; Craig P. (Lafayette, CA), Visco; Steven J. (Berkeley, CA), De Jonghe; Lutgard C. (Lafayette, CA)

    2010-11-09T23:59:59.000Z

    A pre-fabricated electrochemical device having a dense electrolyte disposed between an anode and a cathode preferably deposited as thin films is bonded to a porous electrically conductive support. A second porous electrically conductive support may be bonded to a counter electrode of the electrochemical device. Multiple electrochemical devices may be bonded in parallel to a single porous support, such as a perforated sheet to provide a planar array. Planar arrays may be arranged in a stacked interconnected array. A method of making a supported electrochemical device is disclosed wherein the method includes a step of bonding a pre-fabricated electrochemical device layer to an existing porous metal or porous metal alloy layer.

  11. Planar electrochemical device assembly

    DOE Patents [OSTI]

    Jacobson, Craig P. (Lafayette, CA); Visco, Steven J. (Berkeley, CA); De Jonghe, Lutgard C. (Lafayette, CA)

    2007-06-19T23:59:59.000Z

    A pre-fabricated electrochemical device having a dense electrolyte disposed between an anode and a cathode preferably deposited as thin films is bonded to a porous electrically conductive support. A second porous electrically conductive support may be bonded to a counter electrode of the electrochemical device. Multiple electrochemical devices may be bonded in parallel to a single porous support, such as a perforated sheet to provide a planar array. Planar arrays may be arranged in a stacked interconnected array. A method of making a supported electrochemical device is disclosed wherein the method includes a step of bonding a pre-fabricated electrochemical device layer to an existing porous metal or porous metal alloy layer.

  12. Wafer Fusion for Integration of Semiconductor Materials and Devices

    SciTech Connect (OSTI)

    Choquette, K.D.; Geib, K.M.; Hou, H.Q.; Allerman, A.A.; Kravitz, S.; Follstaedt, D.M.; Hindi, J.J.

    1999-05-01T23:59:59.000Z

    We have developed a wafer fusion technology to achieve integration of semiconductor materials and heterostructures with widely disparate lattice parameters, electronic properties, and/or optical properties for novel devices not now possible on any one substrate. Using our simple fusion process which uses low temperature (400-600 C) anneals in inert N{sub 2} gas, we have extended the scope of this technology to examine hybrid integration of dissimilar device technologies. As a specific example, we demonstrate wafer bonding vertical cavity surface emitting lasers (VCSELs) to transparent AlGaAs and GaP substrates to fabricate bottom-emitting short wavelength VCSELs. As a baseline fabrication technology applicable to many semiconductor systems, wafer fusion will revolutionize the way we think about possible semiconductor devices, and enable novel device configurations not possible by epitaxial growth.

  13. Unoccupied band structure of wurtzite GaN,,0001... T. Valla and P. D. Johnson

    E-Print Network [OSTI]

    Homes, Christopher C.

    Unoccupied band structure of wurtzite GaN,,0001... T. Valla and P. D. Johnson Department of Physics of the unoccupied states of thin-film n-type wurtzite GaN. For incident electron energies below 30 eV, free of electronic devices based on heteroepitaxially grown wurtzite films of these nitrides.1 Extensive investiga

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

    E-Print Network [OSTI]

    Popovic, Zoya

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

  15. Below gap optical absorption in GaAs driven by intense, single-cycle coherent transition radiation

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

    Goodfellow, J.; Fuchs, M.; Daranciang, D.; Ghimire, S.; Chen, F.; Loos, H.; Reis, D. A.; Fisher, A. S.; Lindenberg, A. M.

    2014-01-01T23:59:59.000Z

    Single-cycle terahertz fields generated by coherent transition radiation from a relativistic electron beam are used to study the high field optical response of single crystal GaAs. Large amplitude changes in the sub-band-gap optical absorption are induced and probed dynamically by measuring the absorption of a broad-band optical beam generated by transition radiation from the same electron bunch, providing an absolutely synchronized pump and probe geometry. This modification of the optical properties is consistent with strong-field-induced electroabsorption. These processes are pertinent to a wide range of nonlinear terahertz-driven light-matter interactions anticipated at accelerator-based sources.

  16. Method and device for tensile testing of cable bundles

    DOE Patents [OSTI]

    Robertson, Lawrence M; Ardelean, Emil V; Goodding, James C; Babuska, Vit

    2012-10-16T23:59:59.000Z

    A standard tensile test device is improved to accurately measure the mechanical properties of stranded cables, ropes, and other composite structures wherein a witness is attached to the top and bottom mounting blocks holding the cable under test. The witness is comprised of two parts: a top and a bottom rod of similar diameter with the bottom rod having a smaller diameter stem on its upper end and the top rod having a hollow opening in its lower end into which the stem fits forming a witness joint. A small gap is present between the top rod and the larger diameter portion of the bottom rod. A standard extensometer is attached to the top and bottom rods of the witness spanning this small witness gap. When a force is applied to separate the mounting blocks, the gap in the witness expands the same length that the entire test specimen is stretched.

  17. Dynamics of regeneration gaps following harvest of aspen stands

    E-Print Network [OSTI]

    Macdonald, Ellen

    Dynamics of regeneration gaps following harvest of aspen stands Daniel A. MacIsaac, Philip G in postharvest regeneration in five stands in north- western Alberta dominated by trembling aspen (Populus conditions in 30 aspen regeneration gaps (gaps in regeneration that were not gaps preharvest and were not due

  18. Fine structure of the red luminescence band in undoped GaN

    SciTech Connect (OSTI)

    Reshchikov, M. A., E-mail: mreshchi@vcu.edu [Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284 (United States); Usikov, A. [Nitride Crystals, Inc., 181E Industry Ct., Ste. B, Deer Park, New York 11729 (United States); Saint-Petersburg National Research University of Information Technologies, Mechanics and Optics, 49 Kronverkskiy Ave., 197101 Saint Petersburg (Russian Federation); Helava, H.; Makarov, Yu. [Nitride Crystals, Inc., 181E Industry Ct., Ste. B, Deer Park, New York 11729 (United States)

    2014-01-20T23:59:59.000Z

    Many point defects in GaN responsible for broad photoluminescence (PL) bands remain unidentified. Their presence in thick GaN layers grown by hydride vapor phase epitaxy (HVPE) detrimentally affects the material quality and may hinder the use of GaN in high-power electronic devices. One of the main PL bands in HVPE-grown GaN is the red luminescence (RL) band with a maximum at 1.8?eV. We observed the fine structure of this band with a zero-phonon line (ZPL) at 2.36?eV, which may help to identify the related defect. The shift of the ZPL with excitation intensity and the temperature-related transformation of the RL band fine structure indicate that the RL band is caused by transitions from a shallow donor (at low temperature) or from the conduction band (above 50?K) to an unknown deep acceptor having an energy level 1.130?eV above the valence band.

  19. Energy harvesting devices for harvesting energy from terahertz electromagnetic radiation

    DOE Patents [OSTI]

    Novack, Steven D.; Kotter, Dale K.; Pinhero, Patrick J.

    2012-10-09T23:59:59.000Z

    Methods, devices and systems for harvesting energy from electromagnetic radiation are provided including harvesting energy from electromagnetic radiation. In one embodiment, a device includes a substrate and one or more resonance elements disposed in or on the substrate. The resonance elements are configured to have a resonant frequency, for example, in at least one of the infrared, near-infrared and visible light spectra. A layer of conductive material may be disposed over a portion of the substrate to form a ground plane. An optical resonance gap or stand-off layer may be formed between the resonance elements and the ground plane. The optical resonance gap extends a distance between the resonance elements and the layer of conductive material approximately one-quarter wavelength of a wavelength of the at least one resonance element's resonant frequency. At least one energy transfer element may be associated with the at least one resonance element.

  20. Homolumo gap from dynamical energy levels

    SciTech Connect (OSTI)

    Andric, I.; Jonke, L.; Jurman, D.; Nielsen, H. B. [Theoretical Physics Division, Rudjer Boskovic Institute, P.O. Box 180, 10002 Zagreb (Croatia); Niels Bohr Institute, Copenhagen DK 2100 (Denmark)

    2009-11-15T23:59:59.000Z

    We introduce a dynamical matrix model where the matrix is interpreted as a Hamiltonian representing interaction of a bosonic system with a single fermion. We show how a system of second-quantized fermions influences the ground state of the whole system by producing a gap between the highest eigenvalue of the occupied single-fermion states and the lowest eigenvalue of the unoccupied single-fermion states. We describe the development of the gap in both the strong and weak coupling regimes, while for the intermediate coupling strength we expect formation of homolumo kinks.

  1. Natural Gas Engine Development Gaps (Presentation)

    SciTech Connect (OSTI)

    Zigler, B.T.

    2014-03-01T23:59:59.000Z

    A review of current natural gas vehicle offerings is presented for both light-duty and medium- and heavy-duty applications. Recent gaps in the marketplace are discussed, along with how they have been or may be addressed. The stakeholder input process for guiding research and development needs via the Natural Gas Vehicle Technology Forum (NGVTF) to the U.S. Department of Energy and the California Energy Commission is reviewed. Current high-level natural gas engine development gap areas are highlighted, including efficiency, emissions, and the certification process.

  2. Gribov gap equation at finite temperature

    E-Print Network [OSTI]

    Fabrizio Canfora; Pablo Pais; Patricio Salgado-Rebolledo

    2014-06-05T23:59:59.000Z

    In this paper the Gribov gap equation at finite temperature is analyzed. The solutions of the gap equation (which depend explicitly on the temperature) determine the structure of the gluon propagator within the semi-classical Gribov approach. The present analysis is consistent with the standard confinement scenario for low temperatures, while for high enough temperatures, deconfinement takes place and a free gluon propagator is obtained. It also suggests the presence of the so-called semi-quark-gluon-plasma phase in between the confined and quark-gluon plasma phases.

  3. Ideal light concentrators with reflector gaps

    SciTech Connect (OSTI)

    Winston, Roland (Chicago, IL)

    1980-01-01T23:59:59.000Z

    A cylindrical or trough-like radiant energy concentration and collection device is provided. The device includes an energy absorber, a glazing enveloping the absorber and a reflective wall. The ideal contour of the reflective wall is determined with reference to a virtual absorber and not the actual absorber cross section.

  4. Ideal light concentrators with reflector gaps

    SciTech Connect (OSTI)

    Winston, R.

    1980-10-28T23:59:59.000Z

    A cylindrical or trough-like radiant energy concentration and collection device is provided. The device includes an energy absorber, a glazing enveloping the absorber and a reflective wall. The ideal contour of the reflective wall is determined with reference to a virtual absorber and not the actual absorber cross section.

  5. Bosonic condensation in a flat energy band

    E-Print Network [OSTI]

    Baboux, F; Jacqmin, T; Biondi, M; Lemaître, A; Gratiet, L Le; Sagnes, I; Schmidt, S; Türeci, H E; Amo, A; Bloch, J

    2015-01-01T23:59:59.000Z

    Flat bands are non-dispersive energy bands made of fully degenerate quantum states. Such bands are expected to support emergent phenomena with extraordinary spatial and temporal structures, as they strongly enhance the effect of any perturbation induced by disorder, dissipation or interactions. However, flat bands usually appear at energies above the ground state, preventing their study in systems in thermodynamic equilibrium. Here we use cavity polaritons to circumvent this issue. We engineer a flat band in a frustrated lattice of micro-pillar optical cavities. By taking advantage of the non-hermiticity of our system, we achieve for the first time bosonic condensation in a flat band. This allows revealing the peculiar effect of disorder in such band: The condensate fragments into highly localized modes, reflecting the elementary eigenstates produced by geometric frustration. This non-hermitian engineering of a bosonic flat band condensate offers a novel approach to studying coherent phases of light and matte...

  6. Rain sampling device

    DOE Patents [OSTI]

    Nelson, D.A.; Tomich, S.D.; Glover, D.W.; Allen, E.V.; Hales, J.M.; Dana, M.T.

    1991-05-14T23:59:59.000Z

    The present invention constitutes a rain sampling device adapted for independent operation at locations remote from the user which allows rainfall to be sampled in accordance with any schedule desired by the user. The rain sampling device includes a mechanism for directing wet precipitation into a chamber, a chamber for temporarily holding the precipitation during the process of collection, a valve mechanism for controllably releasing samples of the precipitation from the chamber, a means for distributing the samples released from the holding chamber into vessels adapted for permanently retaining these samples, and an electrical mechanism for regulating the operation of the device. 11 figures.

  7. Rain sampling device

    DOE Patents [OSTI]

    Nelson, Danny A. (Richland, WA); Tomich, Stanley D. (Richland, WA); Glover, Donald W. (Prosser, WA); Allen, Errol V. (Benton City, WA); Hales, Jeremy M. (Kennewick, WA); Dana, Marshall T. (Richland, WA)

    1991-01-01T23:59:59.000Z

    The present invention constitutes a rain sampling device adapted for independent operation at locations remote from the user which allows rainfall to be sampled in accordance with any schedule desired by the user. The rain sampling device includes a mechanism for directing wet precipitation into a chamber, a chamber for temporarily holding the precipitation during the process of collection, a valve mechanism for controllably releasing samples of said precipitation from said chamber, a means for distributing the samples released from the holding chamber into vessels adapted for permanently retaining these samples, and an electrical mechanism for regulating the operation of the device.

  8. Device for conversion of electromagnetic radiation into electrical current

    DOE Patents [OSTI]

    Blakeslee, A.E.; Mitchell, K.W.

    1980-03-25T23:59:59.000Z

    Electromagnetic energy may be converted directly into electrical energy by a device comprising a sandwich of at least two semiconductor portions, each portion having a p-n junction with a characteristic energy gap, and the portions lattice matched to one another by an intervening superlattice structure. This superlattice acts to block propagation into the next deposited portion of those dislocation defects which can form due to lattice mismatch between adjacent portions.

  9. Superconducting gap evolution in overdoped BaFe?(As1-xPx)? single crystals through nanocalorimetry

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

    Campanini, D.; Diao, Z.; Fang, L.; Kwok, W.-K.; Welp, U.; Rydh, A.

    2015-06-01T23:59:59.000Z

    We report on specific heat measurements on clean overdoped BaFe?(As1-xPx)? single crystals performed with a high resolution membrane-based nanocalorimeter. A nonzero residual electronic specific heat coefficient at zero temperature ?r=C/T|T?0 is seen for all doping compositions, indicating a considerable fraction of the Fermi surface ungapped or having very deep minima. The remaining superconducting electronic specific heat is analyzed through a two-band s-wave ? model in order to investigate the gap structure. Close to optimal doping we detect a single zero-temperature gap of ??~5.3 me V, corresponding to ??/kBTc ~ 2.2. Increasing the phosphorus concentration x, the main gap reduces tillmore »a value of ?? ~ 1.9 meV for x = 0.55 and a second weaker gap becomes evident. From the magnetic field effect on ?r, all samples however show similar behavior [?r(H) - ?r (H = 0)? Hn, with n between 0.6 and 0.7]. This indicates that, despite a considerable redistribution of the gap weights, the total degree of gap anisotropy does not change drastically with doping.« less

  10. Superconducting gap evolution in overdoped BaFe?(As1-xPx)? single crystals through nanocalorimetry

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

    Campanini, D.; Diao, Z.; Fang, L.; Kwok, W.-K.; Welp, U.; Rydh, A.

    2015-06-01T23:59:59.000Z

    We report on specific heat measurements on clean overdoped BaFe?(As1-xPx)? single crystals performed with a high resolution membrane-based nanocalorimeter. A nonzero residual electronic specific heat coefficient at zero temperature ?r=C/T|T?0 is seen for all doping compositions, indicating a considerable fraction of the Fermi surface ungapped or having very deep minima. The remaining superconducting electronic specific heat is analyzed through a two-band s-wave ? model in order to investigate the gap structure. Close to optimal doping we detect a single zero-temperature gap of ??~5.3 me V, corresponding to ??/kBTc ~ 2.2. Increasing the phosphorus concentration x, the main gap reduces till a value of ?? ~ 1.9 meV for x = 0.55 and a second weaker gap becomes evident. From the magnetic field effect on ?r, all samples however show similar behavior [?r(H) - ?r (H = 0)? Hn, with n between 0.6 and 0.7]. This indicates that, despite a considerable redistribution of the gap weights, the total degree of gap anisotropy does not change drastically with doping.

  11. Wireless device monitoring systems and monitoring devices, and associated methods

    DOE Patents [OSTI]

    McCown, Steven H; Derr, Kurt W; Rohde, Kenneth W

    2014-05-27T23:59:59.000Z

    Wireless device monitoring systems and monitoring devices include a communications module for receiving wireless communications of a wireless device. Processing circuitry is coupled with the communications module and configured to process the wireless communications to determine whether the wireless device is authorized or unauthorized to be present at the monitored area based on identification information of the wireless device. Methods of monitoring for the presence and identity of wireless devices are also provided.

  12. Band offsets at heterojunctions and the charge neutrality condition

    E-Print Network [OSTI]

    Taferner, Waltraud Teresa

    1990-01-01T23:59:59.000Z

    P InSb ZnSe Znte Gap indirect indirect indirect indirect direct indirect direct direct direct direct direct direct E4 (eV) O'K 0. 76 1. 13 2. 30 1. 88 1. 55 2. 35 0. 78 0. 43 1. 41 0. 23 2. 68 2. 56 If the atoms of a...&' ?r&rl c!?? &'nt h&: R . F. . X I 1 e n t C. 'k&r&ic &?f l'nn&rr&it&ee) l. H. B. r&ss (:& I e m h e r! R. R. L?cchese (lvlpmhe& ) etta. g R. AIT&&J?' &t t (Ifead of Department) May 1990 ABSTRACT Band OfFsets at Heterojunctions...

  13. Narrow band wavelength selective filter using grating assisted single ring resonator

    SciTech Connect (OSTI)

    Prabhathan, P., E-mail: PPrabhathan@ntu.edu.sg; Murukeshan, V. M. [Centre for Optical and Laser Engineering (COLE), School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)

    2014-09-15T23:59:59.000Z

    This paper illustrates a filter configuration which uses a single ring resonator of larger radius connected to a grating resonator at its drop port to achieve single wavelength selectivity and switching property with spectral features suitable for on-chip wavelength selection applications. The proposed configuration is expected to find applications in silicon photonics devices such as, on-chip external cavity lasers and multi analytic label-free biosensors. The grating resonator has been designed for a high Q-factor, high transmittivity, and minimum loss so that the wavelength selectivity of the device is improved. The proof-of-concept device has been demonstrated on a Silicon-on-Insulator (SOI) platform through electron beam lithography and Reactive Ion Etching (RIE) process. The transmission spectrum shows narrow band single wavelength selection and switching property with a high Free Spectral Range (FSR) ?60 nm and side band rejection ratio >15 dB.

  14. Device control at CEBAF

    SciTech Connect (OSTI)

    Schaffner, S.; Barker, D.; Bookwalter, V. [and others

    1996-08-01T23:59:59.000Z

    CEBAF has undergone a major conversion of its accelerator control system from TACL to EPICS, affecting device control for the RF system, magnets, the machine protection system, the vacuum and valves, and the diagnostic systems including beam position monitors, harps, and the camera and solenoid devices (beam viewers, faraday cups, optical transition radiation viewers, synchrotron radiation monitor, etc.). Altogether these devices require approximately 125,000 EPICS database records. The majority of these devices are controlled through CAMAC; some use embedded microprocessors (RF and magnets), and newer interfaces are in VME. The standard EPICS toolkit was extended to include a driver for CAMAC which supports dual processors on one serial highway, custom database records for magnets and BPMs, and custom data acquisition tasks for the BPMs. 2 refs., 1 tab.

  15. Multimaterial rectifying device fibers

    E-Print Network [OSTI]

    Orf, Nicholas D

    2009-01-01T23:59:59.000Z

    Electronic and optoelectronic device processing is commonly thought to be incompatible with much simpler thermal drawing techniques used in optical fiber production. The incorporation of metals, polymer insulators, and ...

  16. FINAL REPORT ON GDE GAP CELL

    SciTech Connect (OSTI)

    Herman, D.; Summers, W.; Danko, E.

    2009-09-28T23:59:59.000Z

    A project has been undertaken to develop an electrochemical cell and support equipment for evaluation of a gas diffusion electrode-based, narrow-electrolyte-gap anode for SO{sub 2} oxidation in the hydrogen production cycle of the hybrid sulfur (HyS) process. The project supported the HyS development program at the Savannah River National Lab (SRNL). The benefits of using a gas diffusion electrode in conjunction with the narrow anolyte gap are being determined through electrochemical polarization testing under a variety conditions, and by comparison to results produced by SRNL and others using anode technologies that have no anolyte gap. These test results indicate that the NGA cell has low resistance suitable for use in the HyS electrolyzer, exhibits good efficiency at high current densities compared to the direct feed HyS electrolyzer, and indicates robust performance in extended testing over 65 hours. Seepage episodes were mostly caused by port clogging, which can be mitigated in future designs through minor modifications to the hardware. Significant reductions in sulfur crossover have not yet been demonstrated in the NGA configuration compared to in-house direct feed testing, but corroborative sulfur layer analysis is as yet incomplete. Further testing in a single-pass anolyte configuration is recommended for complete evaluation of steady-state electrochemical efficiency and SO{sub 2} crossover in the narrow gap configuration.

  17. SHEEP MOUNTAIN URANIUM PROJECT CROOKS GAP, WYOMING

    E-Print Network [OSTI]

    SHEEP MOUNTAIN URANIUM PROJECT CROOKS GAP, WYOMING US EPA Project Meeting April 7 2011April 7, 2011/Titan Uranium, VP Development · Deborah LebowAal/EPA Region 8 Air Program Introduction to Titan Uranium USA;PROJECT OVERVIEW ·Site Location·Site Location ·Fremont , Wyoming ·Existing Uranium Mine Permit 381C

  18. Gapped spin Hamiltonian motivated by quantum teleportation

    E-Print Network [OSTI]

    Ari Mizel

    2014-10-07T23:59:59.000Z

    We construct a Hamiltonian whose ground state encodes a time-independent emulation of quan- tum teleportation. We calculate properties of the Hamiltonian, using exact diagonalization and a mean-field theory, and argue that it has a gap. The system exhibits an illuminating relationship to the well-known AKLT (Affleck, Lieb, Kennedy and Tasaki) model.

  19. Electronic security device

    DOE Patents [OSTI]

    Eschbach, Eugene A. (Richland, WA); LeBlanc, Edward J. (Kennewick, WA); Griffin, Jeffrey W. (Kennewick, WA)

    1992-01-01T23:59:59.000Z

    The present invention relates to a security device having a control box (12) containing an electronic system (50) and a communications loop (14) over which the system transmits a signal. The device is constructed so that the communications loop can extend from the control box across the boundary of a portal such as a door into a sealed enclosure into which access is restricted whereby the loop must be damaged or moved in order for an entry to be made into the enclosure. The device is adapted for detecting unauthorized entries into such enclosures such as rooms or containers and for recording the time at which such entries occur for later reference. Additionally, the device detects attempts to tamper or interfere with the operation of the device itself and records the time at which such events take place. In the preferred embodiment, the security device includes a microprocessor-based electronic system (50) and a detection module (72) capable of registering changes in the voltage and phase of the signal transmitted over the loop.

  20. Electronic security device

    DOE Patents [OSTI]

    Eschbach, E.A.; LeBlanc, E.J.; Griffin, J.W.

    1992-03-17T23:59:59.000Z

    The present invention relates to a security device having a control box containing an electronic system and a communications loop over which the system transmits a signal. The device is constructed so that the communications loop can extend from the control box across the boundary of a portal such as a door into a sealed enclosure into which access is restricted whereby the loop must be damaged or moved in order for an entry to be made into the enclosure. The device is adapted for detecting unauthorized entries into such enclosures such as rooms or containers and for recording the time at which such entries occur for later reference. Additionally, the device detects attempts to tamper or interfere with the operation of the device itself and records the time at which such events take place. In the preferred embodiment, the security device includes a microprocessor-based electronic system and a detection module capable of registering changes in the voltage and phase of the signal transmitted over the loop. 11 figs.

  1. Confirmation of intrinsic electron gap states at nonpolar GaN(1-100) surfaces combining photoelectron and surface optical spectroscopy

    SciTech Connect (OSTI)

    Himmerlich, M., E-mail: marcel.himmerlich@tu-ilmenau.de; Eisenhardt, A.; Shokhovets, S.; Krischok, S. [Institut für Physik and Institut für Mikro- und Nanotechnologien, TU Ilmenau, PF 100565, 98684 Ilmenau (Germany); Räthel, J.; Speiser, E.; Neumann, M. D.; Navarro-Quezada, A.; Esser, N. [Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Albert-Einstein-Strasse 9, 12489 Berlin (Germany)

    2014-04-28T23:59:59.000Z

    The electronic structure of GaN(1–100) surfaces is investigated in-situ by photoelectron spectroscopy (PES) and reflection anisotropy spectroscopy (RAS). Occupied surface states 3.1?eV below the Fermi energy are observed by PES, accompanied by surface optical transitions found in RAS around 3.3?eV, i.e., below the bulk band gap. These results indicate that the GaN(1–100) surface band gap is smaller than the bulk one due to the existence of intra-gap states, in agreement with density functional theory calculations. Furthermore, the experiments demonstrate that RAS can be applied for optical surface studies of anisotropic crystals.

  2. Improving energy storage devices | EMSL

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

    energy storage devices Improving energy storage devices Released: April 15, 2014 Lithium-sulfur batteries last longer with nanomaterial-packed cathode A new PNNL-developed...

  3. RESOLVING THE GAP AND AU-SCALE ASYMMETRIES IN THE PRE-TRANSITIONAL DISK OF V1247 ORIONIS

    SciTech Connect (OSTI)

    Kraus, Stefan; Espaillat, Catherine; Wilner, David J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-78, Cambridge, MA 02138 (United States); Ireland, Michael J. [Department of Physics and Astronomy, Macquarie University, Sydney, NSW 2109 (Australia); Sitko, Michael L.; Swearingen, Jeremy R.; Werren, Chelsea [Department of Physics, University of Cincinnati, Cincinnati, OH 45221 (United States); Monnier, John D.; Calvet, Nuria [Department of Astronomy, University of Michigan, 918 Dennison Building, Ann Arbor, MI 48109 (United States); Grady, Carol A. [Eureka Scientific Inc., Oakland, CA 94602 (United States); Harries, Tim J. [School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom); Hoenig, Sebastian F. [Department of Physics, University of California Santa Barbara, Broida Hall, Santa Barbara, CA 93106 (United States); Russell, Ray W. [The Aerospace Corporation, Los Angeles, CA 90009 (United States)

    2013-05-01T23:59:59.000Z

    Pre-transitional disks are protoplanetary disks with a gapped disk structure, potentially indicating the presence of young planets in these systems. In order to explore the structure of these objects and their gap-opening mechanism, we observed the pre-transitional disk V1247 Orionis using the Very Large Telescope Interferometer, the Keck Interferometer, Keck-II, Gemini South, and IRTF. This allows us to spatially resolve the AU-scale disk structure from near- to mid-infrared wavelengths (1.5-13 {mu}m), tracing material at different temperatures and over a wide range of stellocentric radii. Our observations reveal a narrow, optically thick inner-disk component (located at 0.18 AU from the star) that is separated from the optically thick outer disk (radii {approx}> 46 AU), providing unambiguous evidence for the existence of a gap in this pre-transitional disk. Surprisingly, we find that the gap region is filled with significant amounts of optically thin material with a carbon-dominated dust mineralogy. The presence of this optically thin gap material cannot be deduced solely from the spectral energy distribution, yet it is the dominant contributor at mid-infrared wavelengths. Furthermore, using Keck/NIRC2 aperture masking observations in the H, K', and L' bands, we detect asymmetries in the brightness distribution on scales of {approx}15-40 AU, i.e., within the gap region. The detected asymmetries are highly significant, yet their amplitude and direction changes with wavelength, which is not consistent with a companion interpretation but indicates an inhomogeneous distribution of the gap material. We interpret this as strong evidence for the presence of complex density structures, possibly reflecting the dynamical interaction of the disk material with sub-stellar mass bodies that are responsible for the gap clearing.

  4. Engineering Design of a Multipurpose X-band Accelerating Structure

    E-Print Network [OSTI]

    Gudkov, Dmitry; Samoshkin, Alexander; Zennaro, Riccardo; Dehler, Micha; Raguin, Jean-Yves

    2010-01-01T23:59:59.000Z

    Both FEL projects, SwissFEL and Fermi-Elettra each require an X-band RF accelerating structure for optimal bunch compression at the respective injectors. As the CLIC project is pursuing a program for producing and testing the X-band high-gradient RF structures, a collaboration between PSI, Elettra and CERN has been established to build a multipurpose X-band accelerating structure. This paper focuses on its engineering design, which is based on the disked cells jointed together by diffusion bonding. Vacuum brazing and laser beam welding is used for auxiliary components. The accelerating structure consists of two coupler subassemblies, 73 disks and includes a wakefield monitor and diagnostic waveguides. The engineering study includes the external cooling system, consisting of two parallel cooling circuits and an RF tuning system, which allows phase advance tuning of the cell by deforming the outer wall. The engineering solution for the installation and sealing of the wake field monitor feed-through devices that...

  5. Poisson statistics for random deformed band matrices with power law band width

    E-Print Network [OSTI]

    Vladimir Pchelin

    2015-05-25T23:59:59.000Z

    We show Poisson statistics for random band matrices which diagonal entries have Gaussian components. These components are possibly as small as $n^{-\\varepsilon}$. Particularly, our result is applicable for a band matrix cut from the GUE with the band width satisfying $w^{3.5}density of states (DOS) is obtained for complex deformed Gaussian band matrices with arbitrary $w$. A lower estimate of the DOS is also proven for arbitrary $w$ in a certain class of band matrices.

  6. Results of the GAP-4 experiment on molten-fuel drainage through intersubassembly gap geometry. [LMFBR

    SciTech Connect (OSTI)

    Spencer, B.W.; Vetter, D.; Wesel, R.; Sienicki, J.J.

    1983-01-01T23:59:59.000Z

    One of the key issues in assessment of the meltout phase of a hypothetical core disruptive accident in the LMFBR system involves the timing and paths for dispersal of molten fuel from the disrupted core. A program of experiments is underway at Argonne National Laboratory to investigate molten fuel penetration through these postulated escape paths. The purpose of the GAP-4 test was to examine the penetration distances of molten fuel flowing through the flat, narrow channels representing the intersubassembly gap geometry. In the experiment design, the gap geometry was selected to be two-dimensional on the basis that the gap volume in a reactor design would be interconnected and continuous. The molten fuel used in these tests was a mixture of UO/sub 2/ (81%) and molybdenum (19%) which was generated by an exothermic thermite reaction at a temperature of approx. 3470 K.

  7. Spectral tailoring device

    DOE Patents [OSTI]

    Brager, H.R.; Schenter, R.E.; Carter, L.L.; Karnesky, R.A.

    1987-08-05T23:59:59.000Z

    A spectral tailoring device for altering the neutron energy spectra and flux of neutrons in a fast reactor thereby selectively to enhance or inhibit the transmutation rate of a target metrical to form a product isotope. Neutron moderators, neutron filters, neutron absorbers and neutron reflectors may be used as spectral tailoring devices. Depending on the intended use for the device, a member from each of these four classes of materials could be used singularly, or in combination, to provide a preferred neutron energy spectra and flux of the neutrons in the region of the target material. In one embodiment of the invention, an assembly is provided for enhancing the production of isotopes, such as cobalt 60 and gadolinium 153. In another embodiment of the invention, a spectral tailoring device is disposed adjacent a target material which comprises long lived or volatile fission products and the device is used to shift the neutron energy spectra and flux of neutrons in the region of the fission products to preferentially transmute them to produce a less volatile fission product inventory. 6 figs.

  8. Electrical apparatus lockout device

    SciTech Connect (OSTI)

    Gonzales, Rick (Chesapeake, VA)

    1999-01-01T23:59:59.000Z

    A simple lockout device for electrical equipment equipped with recessed power blades is described. The device comprises a face-plate (12) having a threaded member (14) attached thereto and apertures suitable for accommodating the power blades of a piece of electrical equipment, an elastomeric nose (16) abutting the face-plate having a hole for passage of the threaded member therethrough and power blade apertures in registration with those of the face-plate, a block (20) having a recess (34) in its forward face for receiving at least a portion of the hose, a hole therein for receiving the threaded member and an integral extension (26) extending from its rear face. A thumb screw (22) suitable for turning with the hands and having internal threads suitable for engaging the threaded member attached to the face-plate is inserted into a passage in the integral extension to engage the threaded member in such a fashion that when the device is inserted over the recessed power blades of a piece of electrical equipment and the thumb screw (22) tightened, the elastomeric nose (16) is compressed between the face-plate (12) and the block (20) forcing it to expand laterally thereby securing the device in the recess and precluding the accidental or intentional energization of the piece of equipment by attachment of a power cord to the recessed power blades. Means are provided in the interval extension and the thumb screw for the attachment of a locking device (46) which will satisfy OSHA standards.

  9. Electrical apparatus lockout device

    SciTech Connect (OSTI)

    Gonzales, R.

    1999-10-12T23:59:59.000Z

    A simple lockout device for electrical equipment equipped with recessed power blades is described. The device comprises a face-plate (12) having a threaded member (14) attached thereto and apertures suitable for accommodating the power blades of a piece of electrical equipment, an elastomeric nose (16) abutting the face-plate having a hole for passage of the threaded member therethrough and power blade apertures in registration with those of the face-plate, a block (20) having a recess (34) in its forward face for receiving at least a portion of the hose, a hole therein for receiving the threaded member and an integral extension (26) extending from its rear face. A thumb screw (22) suitable for turning with the hands and having internal threads suitable for engaging the threaded member attached to the face-plate is inserted into a passage in the integral extension to engage the threaded member in such a fashion that when the device is inserted over the recessed power blades of a piece of electrical equipment and the thumb screw (22) tightened, the elastomeric nose (16) is compressed between the face-plate (12) and the block (20) forcing it to expand laterally thereby securing the device in the recess and precluding the accidental or intentional energization of the piece of equipment by attachment of a power cord to the recessed power blades. Means are provided in the interval extension and the thumb screw for the attachment of a locking device (46) which will satisfy OSHA standards.

  10. Comparison of GAP-3 and GAP-4 experiments with conduction freezing calculations. [LMFBR

    SciTech Connect (OSTI)

    Sienicki, J.J.; Spencer, B.W.

    1983-01-01T23:59:59.000Z

    Experiments GAP-3 and GAP-4 were performed at ANL to investigate the ability of molten fuel to penetrate downward through the narrow channels separating adjacent subassemblies during an LMFBR hypothetical core disruptive accident. Molten fuel-metal mixtures (81% UO/sub 2/, 19% Mo) at an initial temperature of 3470/sup 0/K generated by a thermite reaction were injected downward into 1 m long rectangular test sections (gap thickness = 0.43 cm, channel width = 20.3 cm) initially at 1170/sup 0/K simulating the nominal Clinch River Breeder Reactor intersubassembly gap. In the GAP-3 test, a prolonged reaction time of approx. 15 s resulted in segregation of the metallic Mo and oxidic UO/sub 2/ constituents within the reaction vessel prior to injection. Consequently, Mo entered the test section first and froze, forming a complete plug at a penetration distance of 0.18 m. In GAP-4, the reaction time was reduced to approx. 3 s and the constituents remained well mixed upon injection with the result that the leading edge penetration distance increased to 0.35 m. Posttest examination of the cut-open test sections has revealed the existence of stable insulating crusts upon the underlying steel walls with melting and ablation of the walls only very localized.

  11. Picosecond dynamics of a silicon donor based terahertz detector device

    SciTech Connect (OSTI)

    Bowyer, Ellis T.; Li, Juerong; Litvinenko, K. L.; Murdin, B. N., E-mail: b.murdin@surrey.ac.uk, E-mail: yuxm@pku.edu.cn [Advanced Technology Institute, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Villis, B. J.; Erfani, Morteza; Matmon, Guy; Aeppli, Gabriel [London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London WC1H 0AH (United Kingdom); Ortega, Jean-Michel; Prazeres, Rui [Laboratoire de Chemie Physique, Université Paris-Sud 11, 91405 Orsay (France); Dong, Li; Yu, Xiaomei, E-mail: b.murdin@surrey.ac.uk, E-mail: yuxm@pku.edu.cn [Institute of Micro/Nanoelectronics, Peking University, Beijing (China)

    2014-07-14T23:59:59.000Z

    We report the characteristics of a simple complementary metal-oxide-semiconductor compatible terahertz detector device with low response time (nanoseconds) determined using a short-pulse, high intensity free-electron laser. The noise equivalent power was 1?×?10{sup ?11} W Hz{sup ?1/2}. The detector has an enhanced response over narrow bands, most notably at 9.5 THz, with a continuum response at higher frequencies. Using such a device, the dynamics of donors in silicon can be explored, a system which has great potential for quantum information processing.

  12. Nonaqueous Electrical Storage Device

    DOE Patents [OSTI]

    McEwen, Alan B. (Melrose, MA); Evans, David A. (Seekonk, MA); Blakley, Thomas J. (Woburn, MA); Goldman, Jay L. (Mansfield, MA)

    1999-10-26T23:59:59.000Z

    An electrochemical capacitor is disclosed that features two, separated, high surface area carbon cloth electrodes sandwiched between two current collectors fabricated of a conductive polymer having a flow temperature greater than 130.degree. C., the perimeter of the electrochemical capacitor being sealed with a high temperature gasket to form a single cell device. The gasket material is a thermoplastic stable at temperatures greater than 100.degree. C., preferably a polyester or a polyurethane, and having a reflow temperature above 130.degree. C. but below the softening temperature of the current collector material. The capacitor packaging has good mechanical integrity over a wide temperature range, contributes little to the device equivalent series resistance (ESR), and is stable at high potentials. In addition, the packaging is designed to be easily manufacturable by assembly line methods. The individual cells can be stacked in parallel or series configuration to reach the desired device voltage and capacitance.

  13. Pendulum detector testing device

    DOE Patents [OSTI]

    Gonsalves, John M. (Modesto, CA)

    1997-01-01T23:59:59.000Z

    A detector testing device which provides consistent, cost-effective, repeatable results. The testing device is primarily constructed of PVC plastic and other non-metallic materials. Sensitivity of a walk-through detector system can be checked by: 1) providing a standard test object simulating the mass, size and material content of a weapon or other contraband, 2) suspending the test object in successive positions, such as head, waist and ankle levels, simulating where the contraband might be concealed on a person walking through the detector system; and 3) swinging the suspended object through each of the positions, while operating the detector system and observing its response. The test object is retained in a holder in which the orientation of the test device or target can be readily changed, to properly complete the testing requirements.

  14. Regenerative combustion device

    DOE Patents [OSTI]

    West, Phillip B.

    2004-03-16T23:59:59.000Z

    A regenerative combustion device having a combustion zone, and chemicals contained within the combustion zone, such as water, having a first equilibrium state, and a second combustible state. Means for transforming the chemicals from the first equilibrium state to the second combustible state, such as electrodes, are disposed within the chemicals. An igniter, such as a spark plug or similar device, is disposed within the combustion zone for igniting combustion of the chemicals in the second combustible state. The combustion products are contained within the combustion zone, and the chemicals are selected such that the combustion products naturally chemically revert into the chemicals in the first equilibrium state following combustion. The combustion device may thus be repeatedly reused, requiring only a brief wait after each ignition to allow the regeneration of combustible gasses within the head space.

  15. Ion manipulation device

    DOE Patents [OSTI]

    Anderson, Gordon A; Smith, Richard D; Ibrahim, Yehia M; Baker, Erin M

    2014-09-16T23:59:59.000Z

    An ion manipulation method and device is disclosed. The device includes a pair of substantially parallel surfaces. An array of inner electrodes is contained within, and extends substantially along the length of, each parallel surface. The device includes a first outer array of electrodes and a second outer array of electrodes. Each outer array of electrodes is positioned on either side of the inner electrodes, and is contained within and extends substantially along the length of each parallel surface. A DC voltage is applied to the first and second outer array of electrodes. A RF voltage, with a superimposed electric field, is applied to the inner electrodes by applying the DC voltages to each electrode. Ions either move between the parallel surfaces within an ion confinement area or along paths in the direction of the electric field, or can be trapped in the ion confinement area.

  16. Fragment capture device

    DOE Patents [OSTI]

    Payne, Lloyd R. (Los Lunas, NM); Cole, David L. (Albuquerque, NM)

    2010-03-30T23:59:59.000Z

    A fragment capture device for use in explosive containment. The device comprises an assembly of at least two rows of bars positioned to eliminate line-of-sight trajectories between the generation point of fragments and a surrounding containment vessel or asset. The device comprises an array of at least two rows of bars, wherein each row is staggered with respect to the adjacent row, and wherein a lateral dimension of each bar and a relative position of each bar in combination provides blockage of a straight-line passage of a solid fragment through the adjacent rows of bars, wherein a generation point of the solid fragment is located within a cavity at least partially enclosed by the array of bars.

  17. Biochip scanner device

    DOE Patents [OSTI]

    Perov, Alexander (Troitsk, RU); Belgovskiy, Alexander I. (Mayfield Heights, OH); Mirzabekov, Andrei D. (Darien, IL)

    2001-01-01T23:59:59.000Z

    A biochip scanner device used to detect and acquire fluorescence signal data from biological microchips or biochips and method of use are provided. The biochip scanner device includes a laser for emitting a laser beam. A modulator, such as an optical chopper modulates the laser beam. A scanning head receives the modulated laser beam and a scanning mechanics coupled to the scanning head moves the scanning head relative to the biochip. An optical fiber delivers the modulated laser beam to the scanning head. The scanning head collects the fluorescence light from the biochip, launches it into the same optical fiber, which delivers the fluorescence into a photodetector, such as a photodiode. The biochip scanner device is used in a row scanning method to scan selected rows of the biochip with the laser beam size matching the size of the immobilization site.

  18. Electrochromic optical switching device

    DOE Patents [OSTI]

    Lampert, C.M.; Visco, S.J.

    1992-08-25T23:59:59.000Z

    An electrochromic cell is disclosed which comprises an electrochromic layer, a polymerizable organo-sulfur layer which comprises the counter electrode of the structure, and an ionically conductive electronically insulating material which comprises the separator between the electrodes. In a preferred embodiment, both the separator and the organo-sulfur electrode (in both its charged and uncharged states) are transparent either to visible light or to the entire solar spectrum. An electrochromic device is disclosed which comprises such electrodes and separator encased in glass plates on the inner surface of each of which is formed a transparent electrically conductive film in respective electrical contact with the electrodes which facilitates formation of an external electrical connection or contact to the electrodes of the device to permit electrical connection of the device to an external potential source. 3 figs.

  19. Pendulum detector testing device

    DOE Patents [OSTI]

    Gonsalves, J.M.

    1997-09-30T23:59:59.000Z

    A detector testing device is described which provides consistent, cost-effective, repeatable results. The testing device is primarily constructed of PVC plastic and other non-metallic materials. Sensitivity of a walk-through detector system can be checked by: (1) providing a standard test object simulating the mass, size and material content of a weapon or other contraband, (2) suspending the test object in successive positions, such as head, waist and ankle levels, simulating where the contraband might be concealed on a person walking through the detector system; and (3) swinging the suspended object through each of the positions, while operating the detector system and observing its response. The test object is retained in a holder in which the orientation of the test device or target can be readily changed, to properly complete the testing requirements. 5 figs.

  20. Electrochromic optical switching device

    SciTech Connect (OSTI)

    Lampert, Carl M. (El Sobrante, CA); Visco, Steven J. (Berkeley, CA)

    1992-01-01T23:59:59.000Z

    An electrochromic cell is disclosed which comprises an electrochromic layer, a polymerizable organo-sulfur layer which comprises the counter electrode of the structure, and an ionically conductive electronically insulating material which comprises the separator between the electrodes. In a preferred embodiment, both the separator and the organo-sulfur electrode (in both its charged and uncharged states) are transparent either to visible light or to the entire solar spectrum. An electrochromic device is disclosed which comprises such electrodes and separator encased in glass plates on the inner surface of each of which is formed a transparent electrically conductive film in respective electrical contact with the electrodes which facilitates formation of an external electrical connection or contact to the electrodes of the device to permit electrical connection of the device to an external potential source.

  1. Graphene field emission devices

    SciTech Connect (OSTI)

    Kumar, S., E-mail: shishirk@gmail.com; Raghavan, S. [Centre for Nanoscience and Engineering, Indian Institute of Science, Bengaluru (India); Duesberg, G. S. [Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) and School of Chemistry, Trinity College Dublin, Dublin, D2 (Ireland); Pratap, R. [Centre for Nanoscience and Engineering, Indian Institute of Science, Bengaluru (India); Department of Mechanical Engineering, Indian Institute of Science, Bengaluru (India)

    2014-09-08T23:59:59.000Z

    Graphene field emission devices are fabricated using a scalable process. The field enhancement factors, determined from the Fowler-Nordheim plots, are within few hundreds and match the theoretical predictions. The devices show high emission current density of ?10?nA ?m{sup ?1} at modest voltages of tens of volts. The emission is stable with time and repeatable over long term, whereas the noise in the emission current is comparable to that from individual carbon nanotubes emitting under similar conditions. We demonstrate a power law dependence of emission current on pressure which can be utilized for sensing. The excellent characteristics and relative ease of making the devices promise their great potential for sensing and electronic applications.

  2. Gap Assessment in the Emergency Response Community

    SciTech Connect (OSTI)

    Barr, Jonathan L.; Burtner, Edwin R.; Pike, William A.; Peddicord, Annie M Boe; Minsk, Brian S.

    2010-09-27T23:59:59.000Z

    This report describes a gap analysis of the emergency response and management (EM) community, performed during the fall of 2009. Pacific Northwest National Laboratory (PNNL) undertook this effort to identify potential improvements to the functional domains in EM that could be provided by the application of current or future technology. To perform this domain-based gap analysis, PNNL personnel interviewed subject matter experts (SMEs) across the EM domain; to make certain that the analyses reflected a representative view of the community, the SMEs were from a variety of geographic areas and from various sized communities (urban, suburban, and rural). PNNL personnel also examined recent and relevant after-action reports and U.S. Government Accountability Office reports.

  3. On fixed-gap adiabatic quantum computation

    E-Print Network [OSTI]

    Ari Mizel

    2014-01-21T23:59:59.000Z

    Quantum computation has revolutionary potential for speeding algorithms and for simulating quantum systems such as molecules. We report here a quantum computer design that performs universal quantum computation within a single non-degenerate ground state protected from decohering noise by an energy gap that we argue is system-size-independent. Closely analogous to a traditional electric circuit, it substantially changes the requirements for quantum computer construction, easing measurement, timing, and heating problems. Using the standard adiabatic condition, we present evidence that this design permits "quantum concurrent processing" distributing a quantum computation among extra qubits to perform a quantum algorithm of N gates in an amount of time that scales with the square root of N. One consequence of our work is a fixed gap version of adiabatic quantum computation, which several arguments hinted could be impossible.

  4. Phononic crystal devices

    DOE Patents [OSTI]

    El-Kady, Ihab F. (Albuquerque, NM); Olsson, Roy H. (Albuquerque, NM)

    2012-01-10T23:59:59.000Z

    Phononic crystals that have the ability to modify and control the thermal black body phonon distribution and the phonon component of heat transport in a solid. In particular, the thermal conductivity and heat capacity can be modified by altering the phonon density of states in a phononic crystal. The present invention is directed to phononic crystal devices and materials such as radio frequency (RF) tags powered from ambient heat, dielectrics with extremely low thermal conductivity, thermoelectric materials with a higher ratio of electrical-to-thermal conductivity, materials with phononically engineered heat capacity, phononic crystal waveguides that enable accelerated cooling, and a variety of low temperature application devices.

  5. Dielectrophoretic columnar focusing device

    DOE Patents [OSTI]

    James, Conrad D. (Albuquerque, NM); Galambos, Paul C. (Albuquerque, NM); Derzon, Mark S. (Tijeras, NM)

    2010-05-11T23:59:59.000Z

    A dielectrophoretic columnar focusing device uses interdigitated microelectrodes to provide a spatially non-uniform electric field in a fluid that generates a dipole within particles in the fluid. The electric field causes the particles to either be attracted to or repelled from regions where the electric field gradient is large, depending on whether the particles are more or less polarizable than the fluid. The particles can thereby be forced into well defined stable paths along the interdigitated microelectrodes. The device can be used for flow cytometry, particle control, and other process applications, including cell counting or other types of particle counting, and for separations in material control.

  6. Vehicle Codes and Standards: Overview and Gap Analysis

    SciTech Connect (OSTI)

    Blake, C.; Buttner, W.; Rivkin, C.

    2010-02-01T23:59:59.000Z

    This report identifies gaps in vehicle codes and standards and recommends ways to fill the gaps, focusing on six alternative fuels: biodiesel, natural gas, electricity, ethanol, hydrogen, and propane.

  7. Minding the Gap Makes for More Efficient Solar Cells

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

    Minding the Gap Makes for More Efficient Solar Cells Minding the Gap Makes for More Efficient Solar Cells Print Thursday, 19 December 2013 11:01 Using novel materials to develop...

  8. Bridging the Efficiency Gap: Commercial Packaged Rooftop Air Conditioners

    E-Print Network [OSTI]

    Bridging the Efficiency Gap: Commercial Packaged Rooftop Air Conditioners John Shugars, Consultant ofcommercialpackaged air conditioners, explore the reasons behindthis efficiency gap, and assess opportunities). Although sales of rooftop air conditioners have steadily increased over the past decade, the efficiency

  9. RF design of X-band RF deflector for femtosecond diagnostics of LCLS electron beam

    SciTech Connect (OSTI)

    Dolgashev, Valery A.; Wang Juwen [SLAC National Accelerator Laboratory, Menlo Park, CA, 94025 (United States)

    2012-12-21T23:59:59.000Z

    We designed a successful constant impedance traveling wave X-band rf deflector for electron beam diagnostics at the 14 GeV SLAC Linac Coherent Light Source (LCLS). This is the first practical deflector built with a waveguide coupler. The 1-meter rf deflector produces 24 MeV peak transverse kick when powered with 20 MW of 11.424 GHz rf. The design is based on our experience with high gradient X-band accelerating structures. Several deflectors of this design have been built at SLAC and are currently in use. Here we describe the design and distinguishing features of this device.

  10. Condensate removal device

    DOE Patents [OSTI]

    Maddox, James W. (Newport News, VA); Berger, David D. (Alexandria, VA)

    1984-01-01T23:59:59.000Z

    A condensate removal device is disclosed which incorporates a strainer in unit with an orifice. The strainer is cylindrical with its longitudinal axis transverse to that of the vapor conduit in which it is mounted. The orifice is positioned inside the strainer proximate the end which is remoter from the vapor conduit.

  11. Solar Innovator | Alta Devices

    ScienceCinema (OSTI)

    Mattos, Laila; Le, Minh

    2013-05-29T23:59:59.000Z

    Selected to participate in the Energy Department's SunShot Initiative, Alta Devices produces solar cells that convert sunlight into electricity at world record-breaking levels of efficiency. Through its innovative solar technology Alta is helping bring down the cost of solar. Learn more about the Energy Department's efforts to advance solar technology at energy.gov/solar .

  12. Device Oriented Project Controller

    SciTech Connect (OSTI)

    Dalesio, Leo; Kraimer, Martin

    2013-11-20T23:59:59.000Z

    This proposal is directed at the issue of developing control systems for very large HEP projects. A de-facto standard in accelerator control is the Experimental Physics and Industrial Control System (EPICS), which has been applied successfully to many physics projects. EPICS is a channel based system that requires that each channel of each device be configured and controlled. In Phase I, the feasibility of a device oriented extension to the distributed channel database was demonstrated by prototyping a device aware version of an EPICS I/O controller that functions with the current version of the channel access communication protocol. Extensions have been made to the grammar to define the database. Only a multi-stage position controller with limit switches was developed in the demonstration, but the grammar should support a full range of functional record types. In phase II, a full set of record types will be developed to support all existing record types, a set of process control functions for closed loop control, and support for experimental beam line control. A tool to configure these records will be developed. A communication protocol will be developed or extensions will be made to Channel Access to support introspection of components of a device. Performance bench marks will be made on both communication protocol and the database. After these records and performance tests are under way, a second of the grammar will be undertaken.

  13. Cascaded thermoacoustic devices

    DOE Patents [OSTI]

    Swift, Gregory W.; Backhaus, Scott N.; Gardner, David L.

    2003-12-09T23:59:59.000Z

    A thermoacoustic device is formed with a resonator system defining at least one region of high specific acoustic impedance in an acoustic wave within the resonator system. A plurality of thermoacoustic units are cascaded together within the region of high specific acoustic impedance, where at least one of the thermoacoustic units is a regenerator unit.

  14. Liquid mixing device

    SciTech Connect (OSTI)

    O'Leary, R. P.

    1985-08-06T23:59:59.000Z

    A mixing device for mixing at least two liquids to produce a homogenous mixture. The device includes an elongated chamber in which a vertically oriented elongated mixing cavity is located. The cavity is sealed at its lower end and it is open at its upper end and in communication with the interior of the chamber. An elongated conduit extends the length of the cavity and is adapted to receive liquids to be mixed. The conduit includes a plurality of ports located at longitudinally spaced positions therealong and which ports are directed in different directions. The ports create plural streams of liquid which interact and mix with one another within the cavity. The mixed liquids overflow the cavity and out its top end into the chamber 24. The chamber 24 includes an outlet from which the mixed liquids are withdrawn. In accordance with the preferred embodiment gas eductor means are provided in the inlet to the conduit to introduce gas bubbles within the cavity. Gas vent means are also provided in the device to vent any introduced gases from the device so that only the mixed liquids flow out the outlet.

  15. Possible chiral bands in {sup 194}Tl

    SciTech Connect (OSTI)

    Masiteng, P. L.; Ramashidzha, T. M.; Maliage, S. M.; Sharpey-Schafer, J. F.; Vymers, P. A. [iThemba LABS, P.O Box 722, 7129 (South Africa); University of the Western Cape, Private Bag X17, 7535 Bellville (South Africa); Lawrie, E. A.; Lawrie, J. J.; Bark, R. A.; Mullins, S. M.; Murray, S. H. T. [iThemba LABS, P.O Box 722, 7129 (South Africa); Kau, J.; Komati, F. [iThemba LABS, P.O Box 722, 7129 (South Africa); University of the North West, Private Bag X2046, 2735 Mafikeng (South Africa); Lindsay, R. [University of the Western Cape, Private Bag X17, 7535 Bellville (South Africa); Matamba, I. [University of Venda for Science and Technology, Thohoyandou (South Africa); Mutshena, P. [iThemba LABS, P.O Box 722, 7129 (South Africa); University of Venda for Science and Technology, Thohoyandou (South Africa); Zhang, Y. [iThemba LABS, P.O Box 722, 7129 (South Africa); University of Cape Town, Private Bag, 7701 Rondebosch (South Africa)

    2011-10-28T23:59:59.000Z

    High spin states in {sup 194}Tl, excited through the {sup 181}Ta({sup 18}O,5n) fusion evaporation reaction, were studied using the AFRODITE array at iThemba LABS. Candidate chiral bands built on the {pi}h{sub 9/2} x {nu}i{sub 13/2}{sup 1} configuration were found. Furthermore these bands were observed through a band crossing caused by the excitation of a {nu}i{sub 13/2} pair. Above the band crossing the excitation energies remain close, suggesting that chirality may persist for the four quasiparticle configuration too.

  16. Electronic devices containing switchably conductive silicon oxides as a switching element and methods for production and use thereof

    DOE Patents [OSTI]

    Tour, James M; Yao, Jun; Natelson, Douglas; Zhong, Lin; He, Tao

    2013-11-26T23:59:59.000Z

    In various embodiments, electronic devices containing switchably conductive silicon oxide as a switching element are described herein. The electronic devices are two-terminal devices containing a first electrical contact and a second electrical contact in which at least one of the first electrical contact or the second electrical contact is deposed on a substrate to define a gap region therebetween. A switching layer containing a switchably conductive silicon oxide resides in the the gap region between the first electical contact and the second electrical contact. The electronic devices exhibit hysteretic current versus voltage properties, enabling their use in switching and memory applications. Methods for configuring, operating and constructing the electronic devices are also presented herein.

  17. Mott Insulator-Superfluid Transition in a Generalized Bose-Hubbard Model with Topologically Non-trivial Flat-Band

    E-Print Network [OSTI]

    Xing-Hai Zhang; Su-Peng Kou

    2012-05-30T23:59:59.000Z

    In this paper, we studied a generalized Bose-Hubbard model on a checkerboard lattice with topologically nontrivial flat-band. We used mean-field method to decouple the model Hamiltonian and obtained phase diagram by Landau theory of second-order phase transition. We further calculate the energy gap and the dispersion of quasi-particle or quasi-hole in Mott insulator state and found that in strong interaction limit the quasi-particles or the quasi-holes also have flat bands.

  18. CURRENT STATUS OF INSERTION DEVICE DEVELOPMENT AT THE NSLS-II AND ITS FUTURE PLANS

    SciTech Connect (OSTI)

    Tanabe, T.; Chubar, O.; Corwin, T.; Harder, D.A.; He, P.; Kitegi, C.; Rank, J.; Rhein, C.; Rakowsky, G.; Spataro, C.

    2011-03-28T23:59:59.000Z

    National Synchrotron Light Source-II (NSLS-II) project is currently under construction. Procurement of various insertion devices (IDs) has begun. This ring assumes a very high beam stability requirement which imposes tighter field specifications on insertion devices (IDs) compared to the rings of previous generation. The state of the art ID Magnetic Measurement Facility is being set up in order to be able to certify the stringent requirements on the magnetic field of NSLS-II IDs. The IDs in the project baseline scope include six 3.5m long damping wigglers (DWs) with 100mm period length and 15mm pole gap, two 2.0m Elliptically Polarizing Undulator (EPU) with 49mm period and 11.5mm minimum magnetic gap, two 3.0m long 20mm period and one 1.5m long 21mm period IVU, which the minimum gap of these is 5mm and 5.5mm, respectively. Recently a special device for inelastic X-ray scattering (IXS) beamline has been added to the collection of baseline devices. Three pole wigglers with a 28mm magnetic gap and a peak field over 1 Tesla will be utilized to accommodate the users of the type of radiation which is currently produced with bending magnets at the NSLS.

  19. Quasiparticle self-consistent GW calculations for PbS, PbSe, and PbTe: Band structure and pressure coefficients

    E-Print Network [OSTI]

    Svane, Axel Torstein

    and in solar-energy panels.8 With Tl doping PbTe may even exhibit superconductivity.9,10 The lead chalcogenides of states. The pressure-induced gap closure leads to linear Dirac-type band dispersions around the L point states being interchanged.19,25 These states have the same L6 symmetry but different parity and orbital

  20. Band alignment of epitaxial ZnS/Zn3P2 heterojunctions Jeffrey P. Bosco, Steven B. Demers, Gregory M. Kimball, Nathan S. Lewis, and Harry A. Atwater

    E-Print Network [OSTI]

    Kimball, Gregory

    ) Determination of the deep donor-like interface state density distribution in metal/Al2O3/n-GaN structures from phosphide (a- Zn3P2) has a nearly optimal, direct band gap of 1.50 eV and a high visible-light absorption

  1. Non- contacting capacitive diagnostic device

    DOE Patents [OSTI]

    Ellison, Timothy

    2005-07-12T23:59:59.000Z

    A non-contacting capacitive diagnostic device includes a pulsed light source for producing an electric field in a semiconductor or photovoltaic device or material to be evaluated and a circuit responsive to the electric field. The circuit is not in physical contact with the device or material being evaluated and produces an electrical signal characteristic of the electric field produced in the device or material. The diagnostic device permits quality control and evaluation of semiconductor or photovoltaic device properties in continuous manufacturing processes.

  2. Packaging of solid state devices

    DOE Patents [OSTI]

    Glidden, Steven C.; Sanders, Howard D.

    2006-01-03T23:59:59.000Z

    A package for one or more solid state devices in a single module that allows for operation at high voltage, high current, or both high voltage and high current. Low thermal resistance between the solid state devices and an exterior of the package and matched coefficient of thermal expansion between the solid state devices and the materials used in packaging enables high power operation. The solid state devices are soldered between two layers of ceramic with metal traces that interconnect the devices and external contacts. This approach provides a simple method for assembling and encapsulating high power solid state devices.

  3. Course Information --EE 531 Semiconductor Devices and Device Simulation

    E-Print Network [OSTI]

    Hochberg, Michael

    of Semiconductor Devices" by Hess "Si Processing for the VLSI Era: Vol. 3-- The Submicron MOSFET" by Wolf "Advanced: 20% Exam 1: 30% Exam 2: 30% Project: 20% Prerequisite: Semiconductor Devices (EE 482) or equivalent

  4. Turbine blade tip gap reduction system

    DOE Patents [OSTI]

    Diakunchak, Ihor S.

    2012-09-11T23:59:59.000Z

    A turbine blade sealing system for reducing a gap between a tip of a turbine blade and a stationary shroud of a turbine engine. The sealing system includes a plurality of flexible seal strips extending from a pressure side of a turbine blade generally orthogonal to the turbine blade. During operation of the turbine engine, the flexible seal strips flex radially outward extending towards the stationary shroud of the turbine engine, thereby reducing the leakage of air past the turbine blades and increasing the efficiency of the turbine engine.

  5. Closed Gap Enzen | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directedAnnual Siteof EnergyInnovationin UrbanCity ofCityCleanInformation ClimateClio PowerClosed Gap

  6. A Simple Analytical Model for Gaps in Protoplanetary Disks

    E-Print Network [OSTI]

    Duffell, Paul C

    2015-01-01T23:59:59.000Z

    An analytical model is presented for calculating the surface density as a function of radius $\\Sigma(r)$ in protoplanetary disks in which a planet has opened a gap. This model is also applicable to circumbinary disks with extreme binary mass ratios. The gap profile can be solved for algebraically, without performing any numerical integrals. In contrast with previous one-dimensional gap models, this model correctly predicts that low-mass (sub-Jupiter) planets can open gaps in sufficiently low-viscosity disks, and it correctly recovers the power-law dependence of gap depth on planet-to-star mass ratio $q$, disk aspect ratio $h/r$, and dimensionless viscosity $\\alpha$ found in previous numerical studies. Analytical gap profiles are compared with numerical calculations over a range of parameter space in $q$, $h/r$, and $\\alpha$, demonstrating accurate reproduction of the "partial gap" regime, and general agreement over a wide range of parameter space.

  7. Support and maneuvering device

    DOE Patents [OSTI]

    Wood, R.L.

    1987-03-23T23:59:59.000Z

    A support and maneuvering device includes an elongated flexible inflatable enclosure having a fixed end and a movable end. The movable end is collapsible toward the fixed end to a contracted position when the enclosure is in a noninflated condition. Upon inflation, the movable end is movable away from the fixed end to an extended position. The movable end includes means for mounting an article such as a solar reflector thereon. The device also includes a plurality of position controlling means disposed about the movable end to effect adjusting movement of portions thereof by predetermined amounts and for controlling an angle at which the article disposed at the movable end is oriented. The plurality of position controlling means limits a suitable number degrees of freedom of the movable end for transmitting a steering motion thereto and for controlling the position thereof. 9 figs.

  8. Nuclear reactor safety device

    DOE Patents [OSTI]

    Hutter, Ernest (Wilmette, IL)

    1986-01-01T23:59:59.000Z

    A safety device is disclosed for use in a nuclear reactor for axially repositioning a control rod with respect to the reactor core in the event of an upward thermal excursion. Such safety device comprises a laminated helical ribbon configured as a tube-like helical coil having contiguous helical turns with slidably abutting edges. The helical coil is disclosed as a portion of a drive member connected axially to the control rod. The laminated ribbon is formed of outer and inner laminae. The material of the outer lamina has a greater thermal coefficient of expansion than the material of the inner lamina. In the event of an upward thermal excursion, the laminated helical coil curls inwardly to a smaller diameter. Such inward curling causes the total length of the helical coil to increase by a substantial increment, so that the control rod is axially repositioned by a corresponding amount to reduce the power output of the reactor.

  9. Support and maneuvering device

    DOE Patents [OSTI]

    Wood, Richard L. (Arvada, CO)

    1988-01-01T23:59:59.000Z

    A support and maneuvering device includes an elongated flexible inflatable enclosure having a fixed end and a movable end. The movable end is collapsible toward the fixed end to a contracted position when the enclosure is in a noninflated condition. Upon inflation, the movable end is movable away from the fixed end to an extended position. The movable end includes means for mounting an article such as a solar reflector thereon. The device also includes a plurality of position controlling means disposed about the movable end to effect adjusting movement of portions thereof by predetermined amounts and for controlling an angle at which the article disposed at the movable end is oriented. The plurality of position controlling means limits a suitable number degrees of freedom of the movable end for transmitting a steering motion thereto and for controlling the position thereof.

  10. Light modulating device

    DOE Patents [OSTI]

    Rauh, R.D.; Goldner, R.B.

    1989-12-26T23:59:59.000Z

    In a device for transmitting light, means for controlling the transmissivity of the device, including a ceramic, reversibly electrochromic, crystalline element having a highly reflective state when injected with electrons and charge compensating ions and a highly transmissive state when the electrons and ions are removed, the crystalline element being characterized as having a reflectivity of at least 50% in the reflective state and not greater than 10% in the transmissive state, and means for modulating the crystalline element between the reflective and transmissive states by injecting ions into the crystalline element in response to an applied electrical current of a first polarity and removing the ions in response to an applied electrical current of a second polarity are disclosed. 1 fig.

  11. Light modulating device

    DOE Patents [OSTI]

    Rauh, R. David (Newton, MA); Goldner, Ronald B. (Lexington, MA)

    1989-01-01T23:59:59.000Z

    In a device for transmitting light, means for controlling the transmissivity of the device, including a ceramic, reversibly electrochromic, crystalline element having a highly reflective state when injected with electrons and charge compensating ions and a highly transmissive state when the electrons and ions are removed, the crystalline element being characterized as having a reflectivity of at least 50% in the reflective state and not greater than 10% in the transmissive state, and means for modulating the crystalline element between the reflective and transmissive states by injecting ions into the crystalline element in response to an applied electrical current of a first polarity and removing the ions in response to an applied electrical current of a second polarity.

  12. Regenerative braking device

    DOE Patents [OSTI]

    Hoppie, Lyle O. (Birmingham, MI)

    1982-01-12T23:59:59.000Z

    Disclosed are several embodiments of a regenerative braking device for an automotive vehicle. The device includes a plurality of rubber rollers (24, 26) mounted for rotation between an input shaft (14) connectable to the vehicle drivetrain and an output shaft (16) which is drivingly connected to the input shaft by a variable ratio transmission (20). When the transmission ratio is such that the input shaft rotates faster than the output shaft, the rubber rollers are torsionally stressed to accumulate energy, thereby slowing the vehicle. When the transmission ratio is such that the output shaft rotates faster than the input shaft, the rubber rollers are torsionally relaxed to deliver accumulated energy, thereby accelerating or driving the vehicle.

  13. Dielectrokinetic chromatography devices

    DOE Patents [OSTI]

    Chirica, Gabriela S; Fiechtner, Gregory J; Singh, Anup K

    2014-12-16T23:59:59.000Z

    Disclosed herein are methods and devices for dielectrokinetic chromatography. As disclosed, the devices comprise microchannels having at least one perturber which produces a non-uniformity in a field spanning the width of the microchannel. The interaction of the field non-uniformity with a perturber produces a secondary flow which competes with a primary flow. By decreasing the size of the perturber the secondary flow becomes significant for particles/analytes in the nanometer-size range. Depending on the nature of a particle/analyte present in the fluid and its interaction with the primary flow and the secondary flow, the analyte may be retained or redirected. The composition of the primary flow can be varied to affect the magnitude of primary and/or secondary flows on the particles/analytes and thereby separate and concentrate it from other particles/analytes.

  14. Hybrid electroluminescent devices

    SciTech Connect (OSTI)

    Shiang, Joseph John (Niskayuna, NY); Duggal, Anil Raj (Niskayuna, NY); Michael, Joseph Darryl (Schenectady, NY)

    2010-08-03T23:59:59.000Z

    A hybrid electroluminescent (EL) device comprises at least one inorganic diode element and at least one organic EL element that are electrically connected in series. The absolute value of the breakdown voltage of the inorganic diode element is greater than the absolute value of the maximum reverse bias voltage across the series. The inorganic diode element can be a power diode, a Schottky barrier diode, or a light-emitting diode.

  15. Residual gas analysis device

    DOE Patents [OSTI]

    Thornberg, Steven M. (Peralta, NM)

    2012-07-31T23:59:59.000Z

    A system is provided for testing the hermeticity of a package, such as a microelectromechanical systems package containing a sealed gas volume, with a sampling device that has the capability to isolate the package and breach the gas seal connected to a pulse valve that can controllably transmit small volumes down to 2 nanoliters to a gas chamber for analysis using gas chromatography/mass spectroscopy diagnostics.

  16. Temperature measuring device

    DOE Patents [OSTI]

    Lauf, Robert J. (Oak Ridge, TN); Bible, Don W. (Clinton, TN); Sohns, Carl W. (Oak Ridge, TN)

    1999-01-01T23:59:59.000Z

    Systems and methods are described for a wireless instrumented silicon wafer that can measure temperatures at various points and transmit those temperature readings to an external receiver. The device has particular utility in the processing of semiconductor wafers, where it can be used to map thermal uniformity on hot plates, cold plates, spin bowl chucks, etc. without the inconvenience of wires or the inevitable thermal perturbations attendant with them.

  17. Biomolecular detection device

    DOE Patents [OSTI]

    Huo, Qisheng (Albuquerque, NM); Liu, Jun (Albuquerque, NM)

    2008-10-21T23:59:59.000Z

    A device for detecting and measuring the concentration of biomolecules in solution, utilizing a conducting electrode in contact with a solution containing target biomolecules, with a film with controllable pore size distribution characteristics applied to at least one surface of the conducting electrode. The film is functionalized with probe molecules that chemically interact with the target biomolecules at the film surface, blocking indicator molecules present in solution from diffusing from the solution to the electrode, thereby changing the electrochemical response of the electrode.

  18. Thermophotovoltaic energy conversion device

    DOE Patents [OSTI]

    Charache, G.W.; Baldasaro, P.F.; Egley, J.L.

    1998-05-19T23:59:59.000Z

    A thermophotovoltaic device and a method for making the thermophotovoltaic device are disclosed. The device includes an n-type semiconductor material substrate having top and bottom surfaces, a tunnel junction formed on the top surface of the substrate, a region of active layers formed on top of the tunnel junction and a back surface reflector (BSR). The tunnel junction includes a layer of heavily doped n-type semiconductor material that is formed on the top surface of the substrate and a layer of heavily doped p-type semiconductor material formed on the n-type layer. An optional pseudomorphic layer can be formed between the n-type and p-type layers. A region of active layers is formed on top of the tunnel junction. This region includes a base layer of p-type semiconductor material and an emitter layer of n-type semiconductor material. An optional front surface window layer can be formed on top of the emitter layer. An optional interference filter can be formed on top of the emitter layer or the front surface window layer when it is used. 1 fig.

  19. Production of Fast Neutron With Plasma Focus Device

    E-Print Network [OSTI]

    Moshe Gai

    2006-05-05T23:59:59.000Z

    Before its demise DIANA Hi-TECH, LLC, demonstrated the use of two 50 kJoule Plasma Focus devices for the copius production of fast neutrons, x-rays and radio-isotopes. Such a device is suitable for fast neutron non invasive interogation of contra-band materials including hidden nuclear materials. It could be particularly useful for a fast and fail safe interogation of large cargo containers, or in merchant marine port of entries. The performance and fast neutron production (2.5 or 14 MeV at 10^11 or 10^13 neutrons per pulse, respectively) of the two PF50 Plasma Focus devices produced by DIANA HiTECH, LLC, are discussed.

  20. Production of Fast Neutron With Plasma Focus Device

    E-Print Network [OSTI]

    Gai, M

    2006-01-01T23:59:59.000Z

    Before its demise DIANA Hi-TECH, LLC, demonstrated the use of two 50 kJoule Plasma Focus devices for the copius production of fast neutrons, x-rays and radio-isotopes. Such a device is suitable for fast neutron non invasive interogation of contra-band materials including hidden nuclear materials. It could be particularly useful for a fast and fail safe interogation of large cargo containers, or in merchant marine port of entries. The performance and fast neutron production (2.5 or 14 MeV at 10^11 or 10^13 neutrons per pulse, respectively) of the two PF50 Plasma Focus devices produced by DIANA HiTECH, LLC, are discussed.

  1. Extended Supersymmetry in Gapped and Superconducting Graphene

    E-Print Network [OSTI]

    V. K. Oikonomou

    2015-06-27T23:59:59.000Z

    In view of the many quantum field theoretical descriptions of graphene in $2+1$ dimensions, we present another field theoretical feature of graphene, in the presence of defects. Particularly, we shall be interested in gapped graphene in the presence of a domain wall and also for superconducting graphene in the presence of a vortex. As we explicitly demonstrate, the gapped graphene electrons that are localized on the domain wall are associated with four $N=2$ one dimensional supersymmetries, with each pair combining to form an extended $N=4$ supersymmetry with non-trivial topological charges. The case of superconducting graphene is more involved, with the electrons localized on the vortex being associated with $n$ one dimensional supersymmetries, which in turn combine to form an $N=2n$ extended supersymmetry with no-trivial topological charges. As we shall prove, all supersymmetries are unbroken, a feature closely related to the number of the localized fermions and also to the exact form of the associated operators. In addition, the corresponding Witten index is invariant under compact and odd perturbations.

  2. Extended Supersymmetry in Gapped and Superconducting Graphene

    E-Print Network [OSTI]

    V. K. Oikonomou

    2014-11-30T23:59:59.000Z

    In view of the many quantum field theoretical descriptions of graphene in $2+1$ dimensions, we present another field theoretical feature of graphene, in the presence of defects. Particularly, we shall be interested in gapped graphene in the presence of a domain wall and also for superconducting graphene in the presence of a vortex. As we explicitly demonstrate, the gapped graphene electrons that are localized on the domain wall are associated with four $N=2$ one dimensional supersymmetries, with each pair combining to form an extended $N=4$ supersymmetry with non-trivial topological charges. The case of superconducting graphene is more involved, with the electrons localized on the vortex being associated with $n$ one dimensional supersymmetries, which in turn combine to form an $N=2n$ extended supersymmetry with no-trivial topological charges. As we shall prove, all supersymmetries are unbroken, a feature closely related to the number of the localized fermions and also to the exact form of the associated operators. In addition, the corresponding Witten index is invariant under compact and odd perturbations.

  3. Next Generation Nuclear Plant GAP Analysis Report

    SciTech Connect (OSTI)

    Ball, Sydney J [ORNL; Burchell, Timothy D [ORNL; Corwin, William R [ORNL; Fisher, Stephen Eugene [ORNL; Forsberg, Charles W. [Massachusetts Institute of Technology (MIT); Morris, Robert Noel [ORNL; Moses, David Lewis [ORNL

    2008-12-01T23:59:59.000Z

    As a follow-up to the phenomena identification and ranking table (PIRT) studies conducted recently by NRC on next generation nuclear plant (NGNP) safety, a study was conducted to identify the significant 'gaps' between what is needed and what is already available to adequately assess NGNP safety characteristics. The PIRT studies focused on identifying important phenomena affecting NGNP plant behavior, while the gap study gives more attention to off-normal behavior, uncertainties, and event probabilities under both normal operation and postulated accident conditions. Hence, this process also involved incorporating more detailed evaluations of accident sequences and risk assessments. This study considers thermal-fluid and neutronic behavior under both normal and postulated accident conditions, fission product transport (FPT), high-temperature metals, and graphite behavior and their effects on safety. In addition, safety issues related to coupling process heat (hydrogen production) systems to the reactor are addressed, given the limited design information currently available. Recommendations for further study, including analytical methods development and experimental needs, are presented as appropriate in each of these areas.

  4. Quantum confinement in GaP nanoclusters

    SciTech Connect (OSTI)

    Laurich, B.K.; Smith, D.C.; Healy, M.D.

    1994-06-01T23:59:59.000Z

    We have prepared GaP and GaAs nanoclusters from organometallic condensation reactions of E[Si(ChH{sub 3})3]3 (E = P, As) and GaCl{sub 3}. The size of the as synthesized clusters is 10 {Angstrom} to 15 {Angstrom}. Larger clusters of 20 {Angstrom} to 30 {Angstrom} size were obtained by thermal annealing of the as grown material. X-ray diffraction and transmission electron microscopy confirm the high crystalline quality. A lattice contraction of 6.7% could be seen for 10 {Angstrom} sized GaAs clusters. The clusters are nearly spherical in shape. Optical absorption spectra show a distinct line which can be assigned to the fundamental transition of the quantum confined electronic state. The measured blue shift, with respect to the GaP bulk absorption edge is 0.53 eV. As the cluster is smaller than the exciton radius, we can calculate the cluster size from this blue shift and obtain 20.2 {Angstrom}, consistent with the results from X-ray diffraction of 19.5 {Angstrom} for the same sample.

  5. Multimode imaging device

    DOE Patents [OSTI]

    Mihailescu, Lucian; Vetter, Kai M

    2013-08-27T23:59:59.000Z

    Apparatus for detecting and locating a source of gamma rays of energies ranging from 10-20 keV to several MeV's includes plural gamma ray detectors arranged in a generally closed extended array so as to provide Compton scattering imaging and coded aperture imaging simultaneously. First detectors are arranged in a spaced manner about a surface defining the closed extended array which may be in the form a circle, a sphere, a square, a pentagon or higher order polygon. Some of the gamma rays are absorbed by the first detectors closest to the gamma source in Compton scattering, while the photons that go unabsorbed by passing through gaps disposed between adjacent first detectors are incident upon second detectors disposed on the side farthest from the gamma ray source, where the first spaced detectors form a coded aperture array for two or three dimensional gamma ray source detection.

  6. Thermoelectric Materials, Devices and Systems:

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

    -DRAFT - FOR OFFICIAL USE ONLY - DRAFT Thermoelectric Materials, Devices and Systems: 1 Technology Assessment 2 Contents 3 1. Thermoelectric Generation ......

  7. Compact Electrothermal Modeling of an X-band MMIC Sonali Luniya William Batty Vincent Caccamesi Mikael Garcia Carlos Christoffersen

    E-Print Network [OSTI]

    Davis, Rhett

    must be captured at the period of the carrier signals or at least at the envelope rate. Thermal of lumped electrical devices and compact thermal modeling of volu- metric materials enables efficient electrothermal modeling of microwave circuits. The compact thermal model of the body of an X-band MMIC is based

  8. Arc voltage distribution skewness as an indicator of electrode gap during vacuum arc remelting

    DOE Patents [OSTI]

    Williamson, Rodney L. (Albuquerque, NM); Zanner, Frank J. (Sandia Park, NM); Grose, Stephen M. (Glenwood, WV)

    1998-01-01T23:59:59.000Z

    The electrode gap of a VAR is monitored by determining the skewness of a distribution of gap voltage measurements. A decrease in skewness indicates an increase in gap and may be used to control the gap.

  9. Arc voltage distribution skewness as an indicator of electrode gap during vacuum arc remelting

    DOE Patents [OSTI]

    Williamson, R.L.; Zanner, F.J.; Grose, S.M.

    1998-01-13T23:59:59.000Z

    The electrode gap of a VAR is monitored by determining the skewness of a distribution of gap voltage measurements. A decrease in skewness indicates an increase in gap and may be used to control the gap. 4 figs.

  10. Improved Thermoelectric Devices: Advanced Semiconductor Materials for Thermoelectric Devices

    SciTech Connect (OSTI)

    None

    2009-12-11T23:59:59.000Z

    Broad Funding Opportunity Announcement Project: Phononic Devices is working to recapture waste heat and convert it into usable electric power. To do this, the company is using thermoelectric devices, which are made from advanced semiconductor materials that convert heat into electricity or actively remove heat for refrigeration and cooling purposes. Thermoelectric devices resemble computer chips, and they manage heat by manipulating the direction of electrons at the nanoscale. These devices aren’t new, but they are currently too inefficient and expensive for widespread use. Phononic Devices is using a high-performance, cost-effective thermoelectric design that will improve the device’s efficiency and enable electronics manufacturers to more easily integrate them into their products.

  11. Low gap amorphous GaN{sub 1-x}As{sub x} alloys grown on glass substrate

    SciTech Connect (OSTI)

    Yu, K. M.; Liliental-Weber, Z.; Kao, V. M.; Walukiewicz, W. [Materials Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720-8197 (United States); Novikov, S. V.; Foxon, C. T. [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Broesler, R.; Levander, A. X.; Dubon, O. D.; Wu, J. [Materials Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720-8197 (United States); Department of Materials Science and Engineering, University of California, Berkeley, California 94720 (United States)

    2010-09-06T23:59:59.000Z

    Amorphous GaN{sub 1-x}As{sub x} layers with As content in the range of x=0.1 to 0.6 were grown by molecular beam epitaxy on Pyrex glass substrate. These alloys exhibit a wide range of band gap values from 2.2 to 1.3 eV. We found that the density of the amorphous films is {approx}0.8-0.85 of their corresponding crystalline value. These amorphous films have smooth morphology, homogeneous composition, and sharp well defined optical absorption edges. The measured band gap values for the crystalline and amorphous GaN{sub 1-x}As{sub x} alloys are in excellent agreement with the predictions of the band anticrossing model. The high absorption coefficient of {approx}10{sup 5} cm{sup -1} for the amorphous GaN{sub 1-x}As{sub x} films suggests that relatively thin films (on the order of 1 {mu}m) are necessary for photovoltaic application.

  12. First principles electronic band structure and phonon dispersion curves for zinc blend beryllium chalcogenide

    SciTech Connect (OSTI)

    Dabhi, Shweta, E-mail: venu.mankad@gmail.com; Mankad, Venu, E-mail: venu.mankad@gmail.com; Jha, Prafulla K., E-mail: venu.mankad@gmail.com [Department of Physics, Maharaja Krishnakumasinhji Bhavnagar University, Bhavnagar-364001 (India)

    2014-04-24T23:59:59.000Z

    A detailed theoretical study of structural, electronic and Vibrational properties of BeX compound is presented by performing ab-initio calculations based on density-functional theory using the Espresso package. The calculated value of lattice constant and bulk modulus are compared with the available experimental and other theoretical data and agree reasonably well. BeX (X = S,Se,Te) compounds in the ZB phase are indirect wide band gap semiconductors with an ionic contribution. The phonon dispersion curves are represented which shows that these compounds are dynamically stable in ZB phase.

  13. Recent experimental results from a long-pulse J-band relativistic klystron amplifier developmental effort

    SciTech Connect (OSTI)

    Kato, K.G.; Crouch, D.D.; Sar, D.R.; Speciale, R.A. [Hughes Missile Systems Co., Rancho Cucamonga, CA (United States); Carlsten, B.E.; Fazio, M.V.; Haynes, W.B.; Stringfield, R.M. [Los Alamos National Lab., NM (United States)

    1994-12-31T23:59:59.000Z

    Recent experimental results, supporting simulations, and design modeling are presented from a developmental effort to a produce a long pulse ({approximately}1{mu}s) J-band (5.85-8.2 GHz) relativistic klystron amplifier (RKA) of the high current NRL genealogy. This RKA is designed to operate at approximately 6.6 GHz, with a desired RF output {approximately}700 MW. Conversion of electron beam energy to microwave energy is obtained by a mock magnetically insulated coaxial converter which, in various incarnations, can be made to be either a cavity gap extractor or an inverse cathode.

  14. Maximum Likelihood Sub-band Weighting for Robust Speech Recognition

    E-Print Network [OSTI]

    , bins of log filter-band energy (FBE) in each sub-band are multiplied with a weighting factor depending on the reliability of the sub-band. For each sub-band, zero padding is performed on the log FBE vector lengthening. For the DCT has the size of full-band FBE vector, the feature vector consists of the correlations across

  15. Nanoscale Josephson Devices

    E-Print Network [OSTI]

    Bell, Chris

    , ferromagnetically (aligned ferromagnetic layers) FIB Focused Ion Beam GL Ginzburg-Landau GPIB General Purpose Interface Bus GMR Giant Magnetoresistance HTS High Temperature Superconductor I Insulator LED Light Emitting Diode LTS Low Temperature Superconductor MR... . The fabrication of intrinsic Josephson junctions in the high temperature superconductor Tl2Ba2CaCu2O8 will then be discussed, as well as Nb/MoSi2/Nb junctions, superconducting quantum interference devices, and finally GaN light emitting diodes. The work on Tl2Ba2...

  16. Micro environmental sensing device

    DOE Patents [OSTI]

    Polosky, Marc A. (Tijeras, NM); Lukens, Laurance L. (Tijeras, NM)

    2006-05-02T23:59:59.000Z

    A microelectromechanical (MEM) acceleration switch is disclosed which includes a proof mass flexibly connected to a substrate, with the proof mass being moveable in a direction substantially perpendicular to the substrate in response to a sensed acceleration. An electrode on the proof mass contacts one or more electrodes located below the proof mass to provide a switch closure in response to the sensed acceleration. Electrical latching of the switch in the closed position is possible with an optional latching electrode. The MEM acceleration switch, which has applications for use as an environmental sensing device, can be fabricated using micromachining.

  17. Multiported storage devices

    E-Print Network [OSTI]

    Grande, Marcus Bryan

    2000-01-01T23:59:59.000Z

    of niultiported storage device 3 Linux file I/O subsystem 4 Windows NT layered I/O driver model 10 15 5 Location of multiported module in I/O stack 17 6 The bulfer cache . . . 20 7 Queuing of I/O requests 8 Processing of I/O requests by smart blkfiltcr 9... Registering of filter applet via Linux stacked module mechanism . 21 22 . . 26 10 Table of registered filter applets (functions) . . 27 11 Overhead due to presence of smart blkfilter alone . 12 Overhead of smart blkfilter using rot13 filter port 31 33...

  18. Stretchable and foldable electronic devices

    DOE Patents [OSTI]

    2013-10-08T23:59:59.000Z

    Disclosed herein are stretchable, foldable and optionally printable, processes for making devices and devices such as semiconductors, electronic circuits and components thereof that are capable of providing good performance when stretched, compressed, flexed or otherwise deformed. Strain isolation layers provide good strain isolation to functional device layers. Multilayer devices are constructed to position a neutral mechanical surface coincident or proximate to a functional layer having a material that is susceptible to strain-induced failure. Neutral mechanical surfaces are positioned by one or more layers having a property that is spatially inhomogeneous, such as by patterning any of the layers of the multilayer device.

  19. Stretchable and foldable electronic devices

    DOE Patents [OSTI]

    Rogers, John A; Huang, Yonggang; Ko, Heung Cho; Stoykovich, Mark; Choi, Won Mook; Song, Jizhou; Ahn, Jong Hyun; Kim, Dae Hyeong

    2014-12-09T23:59:59.000Z

    Disclosed herein are stretchable, foldable and optionally printable, processes for making devices and devices such as semiconductors, electronic circuits and components thereof that are capable of providing good performance when stretched, compressed, flexed or otherwise deformed. Strain isolation layers provide good strain isolation to functional device layers. Multilayer devices are constructed to position a neutral mechanical surface coincident or proximate to a functional layer having a material that is susceptible to strain-induced failure. Neutral mechanical surfaces are positioned by one or more layers having a property that is spatially inhomogeneous, such as by patterning any of the layers of the multilayer device.

  20. Surface functionalization of graphene devices

    E-Print Network [OSTI]

    Zhang, Xu, S.M. Massachusetts Institute of Technology

    2012-01-01T23:59:59.000Z

    Graphene, a zero-gap semiconductor with massless charge carriers, is emerging as an amazing material for future electronics, due to its outstanding electrical and mechanical performances. However, the lack of a bandgap ...

  1. Propagation of Lamb waves in one-dimensional quasiperiodic composite thin plates: A split of phonon band gap

    E-Print Network [OSTI]

    Li, Baowen

    Propagation of Lamb waves in one-dimensional quasiperiodic composite thin plates: A split of phonon the propagation of Lamb waves in one-dimensional quasiperiodic composite thin plates made of tungsten B spectra, Raman scattering spectra, and propagating modes of acoustic waves on corrugated surfaces.14

  2. Band Gap Energy of Chalcopyrite Thin Film Solar Cell Absorbers Determined by Soft X-Ray Emission and Absorption Spectroscopy

    E-Print Network [OSTI]

    Bar, M.

    2010-01-01T23:59:59.000Z

    8] J.R. Tuttle et al. , Solar Cells 30, 21 (1991). [9] D.OF CHALCOPYRITE THIN FILM SOLAR CELL ABSORBERS DETERMINED BYchalcopyrite thin film solar cell absorbers significantly

  3. One-photon band gap engineering of borate glass doped with ZnO for photonics applications

    SciTech Connect (OSTI)

    Abdel-Baki, Manal [Glass Department, National Research Centre, Dokki 12311 Giza (Egypt); Abdel-Wahab, Fathy A.; El-Diasty, Fouad [Physics Department, Faculty of Science, Ain Shams University, Abbasia, 11566 Cairo (Egypt)

    2012-04-01T23:59:59.000Z

    Lithium tungsten borate glass of the composition (0.56-x)B{sub 2}O{sub 3}-0.4Li{sub 2}O-xZnO-0.04WO{sub 3} (0 {<=}x{<=} 0.1 mol. %) is prepared for photonics applications. The glass is doped with ZnO to tune the glass absorption characteristics in a wide spectrum range (200-2500 nm). Chemical bond approach, including chemical structure, electronegativity, bond ionicity, nearest-neighbor coordination, and other chemical bonding aspect, is used to analyze and to explain the obtained glass properties such as: transmittance, absorption, electronic structure parameters (bandgap, Fermi level, and Urbach exciton-phonon coupling), Wannier free excitons excitation (applying Elliott's model), and two-photon absorption coefficient as a result of replacement of B{sub 2}O{sub 3} by ZnO.

  4. Exploring Visible-Light-Responsive Photocatalysts for Water Splitting Based on Novel Band-gap Engineering Strategies

    E-Print Network [OSTI]

    Liu, Jikai

    2013-01-01T23:59:59.000Z

    B 4.3 C before and after photocatalysis reaction (top) and BC 2 before and after photocatalysis reaction (bottom). PageB 4.3 C before and after photocatalysis reaction (top) and B

  5. Carbon based prosthetic devices

    SciTech Connect (OSTI)

    Devlin, D.J.; Carroll, D.W.; Barbero, R.S.; Archuleta, T. [Los Alamos National Lab., NM (US); Klawitter, J.J.; Ogilvie, W.; Strzepa, P. [Ascension Orthopedics (US); Cook, S.D. [Tulane Univ., New Orleans, LA (US). School of Medicine

    1998-12-31T23:59:59.000Z

    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project objective was to evaluate the use of carbon/carbon-fiber-reinforced composites for use in endoprosthetic devices. The application of these materials for the metacarpophalangeal (MP) joints of the hand was investigated. Issues concerning mechanical properties, bone fixation, biocompatibility, and wear are discussed. A system consisting of fiber reinforced materials with a pyrolytic carbon matrix and diamond-like, carbon-coated wear surfaces was developed. Processes were developed for the chemical vapor infiltration (CVI) of pyrolytic carbon into porous fiber preforms with the ability to tailor the outer porosity of the device to provide a surface for bone in-growth. A method for coating diamond-like carbon (DLC) on the articulating surface by plasma-assisted chemical vapor deposition (CVD) was developed. Preliminary results on mechanical properties of the composite system are discussed and initial biocompatibility studies were performed.

  6. Fluid flow monitoring device

    DOE Patents [OSTI]

    McKay, M.D.; Sweeney, C.E.; Spangler, B.S. Jr.

    1993-11-30T23:59:59.000Z

    A flow meter and temperature measuring device are described comprising a tube with a body centered therein for restricting flow and a sleeve at the upper end of the tube to carry several channels formed longitudinally in the sleeve to the appropriate axial location where they penetrate the tube to allow pressure measurements and temperature measurements with thermocouples. The high pressure measurement is made using a channel penetrating the tube away from the body and the low pressure measurement is made at a location at the widest part of the body. An end plug seals the end of the device and holes at its upper end allow fluid to pass from the interior of the tube into a plenum. The channels are made by cutting grooves in the sleeve, the grooves widened at the surface of the sleeve and then a strip of sleeve material is welded to the grooves closing the channels. Preferably the sleeve is packed with powdered graphite before cutting the grooves and welding the strips. 7 figures.

  7. Fluid flow monitoring device

    DOE Patents [OSTI]

    McKay, Mark D. (1426 Socastee Dr., North Augusta, SC 29841); Sweeney, Chad E. (3600 Westhampton Dr., Martinez, GA 30907-3036); Spangler, Jr., B. Samuel (2715 Margate Dr., Augusta, GA 30909)

    1993-01-01T23:59:59.000Z

    A flow meter and temperature measuring device comprising a tube with a body centered therein for restricting flow and a sleeve at the upper end of the tube to carry several channels formed longitudinally in the sleeve to the appropriate axial location where they penetrate the tube to allow pressure measurements and temperature measurements with thermocouples. The high pressure measurement is made using a channel penetrating the tube away from the body and the low pressure measurement is made at a location at the widest part of the body. An end plug seals the end of the device and holes at its upper end allow fluid to pass from the interior of the tube into a plenum. The channels are made by cutting grooves in the sleeve, the grooves widened at the surface of the sleeve and then a strip of sleeve material is welded to the grooves closing the channels. Preferably the sleeve is packed with powdered graphite before cutting the grooves and welding the strips.

  8. Sensitivity Analysis of the Gap Heat Transfer Model in BISON.

    SciTech Connect (OSTI)

    Swiler, Laura Painton; Schmidt, Rodney C.; Williamson, Richard (INL); Perez, Danielle (INL)

    2014-10-01T23:59:59.000Z

    This report summarizes the result of a NEAMS project focused on sensitivity analysis of the heat transfer model in the gap between the fuel rod and the cladding used in the BISON fuel performance code of Idaho National Laboratory. Using the gap heat transfer models in BISON, the sensitivity of the modeling parameters and the associated responses is investigated. The study results in a quantitative assessment of the role of various parameters in the analysis of gap heat transfer in nuclear fuel.

  9. Dipole Bands in {sup 196}Hg

    SciTech Connect (OSTI)

    Lawrie, J. J.; Lawrie, E. A.; Newman, R. T.; Sharpey-Schafer, J. F.; Smit, F. D. [iThemba LABS, PO Box 722, Somerset West 7129 (South Africa); Msezane, B. [iThemba LABS, PO Box 722, Somerset West 7129 (South Africa); Physics Department, University of Zululand, Private Bag X1001, Kwadlangezwa 3886 (South Africa); Benatar, M.; Mabala, G. K.; Mutshena, K. P. [iThemba LABS, PO Box 722, Somerset West 7129 (South Africa); Physics Department, University of Cape Town, Rondebosch 7700 (South Africa); Federke, M.; Mullins, S. M. [Physics Department, University of Cape Town, Rondebosch 7700 (South Africa); Ncapayi, N. J.; Vymers, P. [iThemba LABS, PO Box 722, Somerset West 7129 (South Africa); Physics Department, University of the Western Cape, Private Bag X17, Belleville 7535 (South Africa)

    2011-10-28T23:59:59.000Z

    High spin states in {sup 196}Hg have been populated in the {sup 198}Pt({alpha},6n) reaction at 65 MeV and the level scheme has been extended. A new dipole band has been observed and a previously observed dipole has been confirmed. Excitation energies, spins and parities of these bands were determined from DCO ratio and linear polarization measurements. Possible quasiparticle excitations responsible for these structures are discussed.

  10. Sandia National Laboratories: projected gap between western U...

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

    projected gap between western U.S. water supply and demand Sandia, the Atlantic Council, and NM Water Resource Research Institute Sponsor Roundtable on Western Water Scarcity On...

  11. Rapidity gaps in jet events at D0

    SciTech Connect (OSTI)

    Abbott, B. [New York Univ., NY (United States); Abolins, M. [Michigan State Univ., East Lansing, MI (United States); Acharya, B.S. [Delhi Univ. (India)] [and others; D0 Collaboration

    1997-07-01T23:59:59.000Z

    Preliminary results from the D0 experiment on jet production with rapidity gaps in p{anti p} collisions are presented. A class of dijet events with a forward rapidity gap is observed at center-of-mass energies {radical}s = 1800 GeV and 630 GeV. The number of events with rapidity gaps at both center-of-mass energies is significantly greater than the expectation from multiplicity fluctuations and is consistent with a hard diffractive process. A class of events with two forward gaps and central dijets is also observed at 1800 GeV. This topology is consistent with hard double pomeron exchange.

  12. alteration print gap: Topics by E-print Network

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

    Elihu, David Morad 2006-01-01 2 Bridging the Gap: Automated Steady Scaffoldings for 3D Printing Jrmie Dumas Computer Technologies and Information Sciences Websites Summary:...

  13. FAQS Gap Analysis Qualification Card – Fire Protection Engineering

    Broader source: Energy.gov [DOE]

    Functional Area Qualification Standard Gap Analysis Qualification Cards outline the differences between the last and latest version of the FAQ Standard.

  14. FAQS Gap Analysis Qualification Card – Nuclear Explosive Safety Study

    Broader source: Energy.gov [DOE]

    Functional Area Qualification Standard Gap Analysis Qualification Cards outline the differences between the last and latest version of the FAQ Standard.

  15. Catalysis by Design: Bridging the Gap between Theory and Experiments...

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

    between Theory and Experiments Catalysis by Design: Bridging the Gap between Theory and Experiments Poster presentation at the 2007 Diesel Engine-Efficiency & Emissions Research...

  16. Catalysis by Design: Bridging the Gap Between Theory and Experiments...

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

    Between Theory and Experiments at Nanoscale Level Catalysis by Design: Bridging the Gap Between Theory and Experiments at Nanoscale Level Studies on a simple platinum-alumina...

  17. Behavioral/Systems/Cognitive Synchronous, Focally Modulated -Band Oscillations

    E-Print Network [OSTI]

    Graybiel, Ann M.

    , primarily synchronous -band voltage oscillations occur in the sensorimotor and frontal cortex of humansBehavioral/Systems/Cognitive Synchronous, Focally Modulated -Band Oscillations Characterize Local oscillations in the -frequency band ( 15­30Hz

  18. Surface photovoltage measurements and finite element modeling of SAW devices.

    SciTech Connect (OSTI)

    Donnelly, Christine

    2012-03-01T23:59:59.000Z

    Over the course of a Summer 2011 internship with the MEMS department of Sandia National Laboratories, work was completed on two major projects. The first and main project of the summer involved taking surface photovoltage measurements for silicon samples, and using these measurements to determine surface recombination velocities and minority carrier diffusion lengths of the materials. The SPV method was used to fill gaps in the knowledge of material parameters that had not been determined successfully by other characterization methods. The second project involved creating a 2D finite element model of a surface acoustic wave device. A basic form of the model with the expected impedance response curve was completed, and the model is ready to be further developed for analysis of MEMS photonic resonator devices.

  19. A Mid-infrared QEPAS sensor device for TATP detection , U Willer1

    E-Print Network [OSTI]

    A Mid-infrared QEPAS sensor device for TATP detection C Bauer1 , U Willer1 , R Lewicki2 applications in laser spectroscopy of trace gas species in the mid-infrared spectral region. We report for the detection of the explosive TATP which is a mid infrared broad band absorber. The detection limit of our

  20. 1928 IEEE TRANSACTIONS ON ELECTRON DEVICES, VOL. 51, NO. 11, NOVEMBER 2004 Briefs___________________________________________________________________________________________

    E-Print Network [OSTI]

    Dutton, Robert W.

    -Si devices have self-heating problems due to the lower thermal conductivity of the buried SiGe layer simulation, electrostatic dis- charge (ESD), fullband Monte Carlo simulation, phonon mean-free-path, self-heating that induces repopulation of the energy bands [2]. On the other hand, self-heating problems can cause

  1. Opportunistic, collaborative and synchronized, proximal device ecology

    E-Print Network [OSTI]

    Toledano, Eyal

    2013-01-01T23:59:59.000Z

    CoSync is an on-device software framework for coordinating proximal consumer electronic devices in order to create a synchronized, opportunistic and collaborative device ecology. The CoSync device ecology combines multiple ...

  2. Tunable surface plasmon devices

    DOE Patents [OSTI]

    Shaner, Eric A. (Rio Rancho, NM); Wasserman, Daniel (Lowell, MA)

    2011-08-30T23:59:59.000Z

    A tunable extraordinary optical transmission (EOT) device wherein the tunability derives from controlled variation of the dielectric constant of a semiconducting material (semiconductor) in evanescent-field contact with a metallic array of sub-wavelength apertures. The surface plasmon resonance wavelength can be changed by changing the dielectric constant of the dielectric material. In embodiments of this invention, the dielectric material is a semiconducting material. The dielectric constant of the semiconducting material in the metal/semiconductor interfacial region is controllably adjusted by adjusting one or more of the semiconductor plasma frequency, the concentration and effective mass of free carriers, and the background high-frequency dielectric constant in the interfacial region. Thermal heating and/or voltage-gated carrier-concentration changes may be used to variably adjust the value of the semiconductor dielectric constant.

  3. Personal annunciation device

    DOE Patents [OSTI]

    Angelo, Peter (Oak Ridge, TN); Younkin, James (Oak Ridge, TN); DeMint, Paul (Kingston, TN)

    2011-01-25T23:59:59.000Z

    A personal annunciation device (PAD) providing, in an area of interest, compensatory annunciation of the presence of an abnormal condition in a hazardous area and accountability of the user of the PAD. Compensatory annunciation supplements primary annunciation provided by an emergency notification system (ENS). A detection system detects an abnormal condition, and a wireless transmission system transmits a wireless transmission to the PAD. The PAD has a housing enclosing the components of the PAD including a communication module for receiving the wireless transmission, a power supply, processor, memory, annunciation system, and RFID module. The RFID module has an RFID receiver that listens for an RFID transmission from an RFID reader disposed in a portal of an area of interest. The PAD identifies the transmission and changes its operating state based on the transmission. The RFID readers recognize, record, and transmit the state of the PAD to a base station providing accountability of the wearer.

  4. Nuclear reactor safety device

    DOE Patents [OSTI]

    Hutter, E.

    1983-08-15T23:59:59.000Z

    A safety device is described for use in a nuclear reactor for axially repositioning a control rod with respect to the reactor core in the event of a thermal excursion. It comprises a laminated strip helically configured to form a tube, said tube being in operative relation to said control rod. The laminated strip is formed of at least two materials having different thermal coefficients of expansion, and is helically configured such that the material forming the outer lamina of the tube has a greater thermal coefficient of expansion than the material forming the inner lamina of said tube. In the event of a thermal excursion the laminated strip will tend to curl inwardly so that said tube will increase in length, whereby as said tube increases in length it exerts a force on said control rod to axially reposition said control rod with respect to said core.

  5. False color viewing device

    DOE Patents [OSTI]

    Kronberg, J.W.

    1991-05-08T23:59:59.000Z

    This invention consists of a viewing device for observing objects in near-infrared false-color comprising a pair of goggles with one or more filters in the apertures, and pads that engage the face for blocking stray light from the sides so that all light reaching, the user`s eyes come through the filters. The filters attenuate most visible light and pass near-infrared (having wavelengths longer than approximately 700 nm) and a small amount of blue-green and blue-violet (having wavelengths in the 500 to 520 nm and shorter than 435 nm, respectively). The goggles are useful for looking at vegetation to identify different species and for determining the health of the vegetation, and to detect some forms of camouflage.

  6. False color viewing device

    DOE Patents [OSTI]

    Kronberg, James W. (108 Independent Blvd., Aiken, SC 29801)

    1992-01-01T23:59:59.000Z

    A viewing device for observing objects in near-infrared false-color comprising a pair of goggles with one or more filters in the apertures, and pads that engage the face for blocking stray light from the sides so that all light reaching the user's eyes come through the filters. The filters attenuate most visible light and pass near-infrared (having wavelengths longer than approximately 700 nm) and a small amount of blue-green and blue-violet (having wavelengths in the 500 to 520 nm and shorter than 435 nm, respectively). The goggles are useful for looking at vegetation to identify different species and for determining the health of the vegetation, and to detect some forms of camouflage.

  7. False color viewing device

    DOE Patents [OSTI]

    Kronberg, J.W.

    1992-10-20T23:59:59.000Z

    A viewing device for observing objects in near-infrared false-color comprising a pair of goggles with one or more filters in the apertures, and pads that engage the face for blocking stray light from the sides so that all light reaching the user's eyes come through the filters. The filters attenuate most visible light and pass near-infrared (having wavelengths longer than approximately 700 nm) and a small amount of blue-green and blue-violet (having wavelengths in the 500 to 520 nm and shorter than 435 nm, respectively). The goggles are useful for looking at vegetation to identify different species and for determining the health of the vegetation, and to detect some forms of camouflage. 7 figs.

  8. Multichannel optical sensing device

    DOE Patents [OSTI]

    Selkowitz, Stephen E. (Piedmont, CA)

    1990-01-01T23:59:59.000Z

    A multichannel optical sensing device is disclosed, for measuring the outr sky luminance or illuminance or the luminance or illuminance distribution in a room, comprising a plurality of light receptors, an optical shutter matrix including a plurality of liquid crystal optical shutter elements operable by electrical control signals between light transmitting and light stopping conditions, fiber optic elements connected between the receptors and the shutter elements, a microprocessor based programmable control unit for selectively supplying control signals to the optical shutter elements in a programmable sequence, a photodetector including an optical integrating spherical chamber having an input port for receiving the light from the shutter matrix and at least one detector element in the spherical chamber for producing output signals corresponding to the light, and output units for utilizing the output signals including a storage unit having a control connection to the microprocessor based programmable control unit for storing the output signals under the sequence control of the programmable control unit.

  9. Multichannel optical sensing device

    DOE Patents [OSTI]

    Selkowitz, S.E.

    1985-08-16T23:59:59.000Z

    A multichannel optical sensing device is disclosed, for measuring the outdoor sky luminance or illuminance or the luminance or illuminance distribution in a room, comprising a plurality of light receptors, an optical shutter matrix including a plurality of liquid crystal optical shutter elements operable by electrical control signals between light transmitting and light stopping conditions, fiber optical elements connected between the receptors and the shutter elements, a microprocessor based programmable control unit for selectively supplying control signals to the optical shutter elements in a programmable sequence, a photodetector including an optical integrating spherical chamber having an input port for receiving the light from the shutter matrix and at least one detector element in the spherical chamber for producing output signals corresponding to the light, and output units for utilizing the output signals including a storage unit having a control connection to the microprocessor based programmable control unit for storing the output signals under the sequence control of the programmable control unit.

  10. Electrical safety device

    DOE Patents [OSTI]

    White, David B. (Greenock, PA)

    1991-01-01T23:59:59.000Z

    An electrical safety device for use in power tools that is designed to automatically discontinue operation of the power tool upon physical contact of the tool with a concealed conductive material. A step down transformer is used to supply the operating power for a disconnect relay and a reset relay. When physical contact is made between the power tool and the conductive material, an electrical circuit through the disconnect relay is completed and the operation of the power tool is automatically interrupted. Once the contact between the tool and conductive material is broken, the power tool can be quickly and easily reactivated by a reset push button activating the reset relay. A remote reset is provided for convenience and efficiency of operation.

  11. Light emitting ceramic device

    DOE Patents [OSTI]

    Valentine, Paul; Edwards, Doreen D.; Walker, Jr., William John; Slack, Lyle H.; Brown, Wayne Douglas; Osborne, Cathy; Norton, Michael; Begley, Richard

    2010-05-18T23:59:59.000Z

    A light-emitting ceramic based panel, hereafter termed "electroceramescent" panel, is herein claimed. The electroceramescent panel is formed on a substrate providing mechanical support as well as serving as the base electrode for the device. One or more semiconductive ceramic layers directly overlay the substrate, and electrical conductivity and ionic diffusion are controlled. Light emitting regions overlay the semiconductive ceramic layers, and said regions consist sequentially of a layer of a ceramic insulation layer and an electroluminescent layer, comprised of doped phosphors or the equivalent. One or more conductive top electrode layers having optically transmissive areas overlay the light emitting regions, and a multi-layered top barrier cover comprising one or more optically transmissive non-combustible insulation layers overlay said top electrode regions.

  12. Module isolation devices

    SciTech Connect (OSTI)

    Carolan, Michael Francis; Cooke, John Albert; Buzinski, Michael David

    2010-04-27T23:59:59.000Z

    A gas flow isolation device includes a gas flow isolation valve movable from an opened condition to a closed condition. The module isolation valve in one embodiment includes a rupture disk in flow communication with a flow of gas when the module isolation valve is in an opened condition. The rupture disk ruptures when a predetermined pressure differential occurs across it causing the isolation valve to close. In one embodiment the valve is mechanically linked to the rupture disk to maintain the valve in an opened condition when the rupture disk is intact, and which permits the valve to move into a closed condition when the rupture disk ruptures. In another embodiment a crushable member maintains the valve in an open condition, and the flow of gas passed the valve upon rupturing of the rupture disk compresses the crushable member to close the isolation valve.

  13. Air bag restraint device

    DOE Patents [OSTI]

    Marts, D.J.; Richardson, J.G.

    1995-10-17T23:59:59.000Z

    A rear-seat air bag restraint device is disclosed that prevents an individual, or individuals, from continuing violent actions while being transported in a patrol vehicle`s rear seat without requiring immediate physical contact by the law enforcement officer. The air bag is activated by a control switch in the front seat and inflates to independently restrict the amount of physical activity occurring in the rear seat of the vehicle while allowing the officer to safely stop the vehicle. The air bag can also provide the officer additional time to get backup personnel to aid him if the situation warrants it. The bag is inflated and maintains a constant pressure by an air pump. 8 figs.

  14. Control Banding and Nanotechnology Synergist

    SciTech Connect (OSTI)

    Zalk, D; Paik, S

    2009-12-15T23:59:59.000Z

    The average Industrial Hygienist (IH) loves a challenge, right? Okay, well here is one with more than a few twists. We start by going through the basics of a risk assessment. You have some chemical agents, a few workers, and the makings of your basic exposure characterization. However, you have no occupational exposure limit (OEL), essentially no toxicological basis, and no epidemiology. Now the real handicap is that you cannot use sampling pumps, cassettes, tubes, or any of the media in your toolbox, and the whole concept of mass-to-dose is out the window, even at high exposure levels. Of course, by the title, you knew we were talking about nanomaterials (NM). However, we wonder how many IHs know that this topic takes everything you know about your profession and turns it upside down. It takes the very foundations that you worked so hard in college and in the field to master and pulls it out from underneath you. It even takes the gold standard of our profession, the quantitative science of exposure assessment, and makes it look pretty darn rusty. Now with NM there is the potential to get some aspect of quantitative measurements, but the instruments are generally very expensive and getting an appropriate workplace personal exposure measurement can be very difficult if not impossible. The potential for workers getting exposures, however, is very real, as evidenced by a recent publication reporting worker exposures to polyacrylate nanoparticles in a Chinese factory (Song et al. 2009). With something this complex and challenging, how does a concept as simple as Control Banding (CB) save the day? Although many IHs have heard of CB, most of their knowledge comes from its application in the COSHH Essentials toolkit. While there is conflicting published research on COSHH Essentials and its value for risk assessments, almost all of the experts agree that it can be useful when no OELs are available (Zalk and Nelson 2008). It is this aspect of CB, its utility with uncertainty, that attracted international NM experts to recommend this qualitative risk assessment approach for NM. However, since their CB recommendation was only in theory, we took on the challenge of developing a working toolkit, the CB Nanotool (see Zalk et al. 2009 and Paik et al. 2008), as a means to perform a risk assessment and protect researchers at the Lawrence Livermore National Laboratory. While it's been acknowledged that engineered NM have potentially endless benefits for society, it became clear to us that the very properties that make nanotechnology so useful to industry could also make them dangerous to humans and the environment. Among the uncertainties and unknowns with NM are: the contribution of their physical structure to their toxicity, significant differences in their deposition and clearance in the lungs when compared to their parent material (PM), a lack of agreement on the appropriate indices for exposure to NM, and very little background information on exposure scenarios or populations at risk. Part of this lack of background information can be traced to the lack of risk assessments historically performed in the industry, with a recent survey indicating that 65% of companies working with NM are not doing any kind of NM-specific risk assessment as they focus on traditional PM methods for IH (Helland et al. 2009). The good news is that the amount of peer-reviewed publications that address environmental, health and safety aspects of NM has been increasing over the last few years; however, the percentage of these that address practical methods to reduce exposure and protect workers is orders of magnitude lower. Our intent in developing the CB Nanotool was to create a simplified approach that would protect workers while unraveling the mysteries of NM for experts and non-experts alike. Since such a large part of the toxicological effects of both the physical and chemical properties of NM were unknown, not to mention changing logarithmically as new NM research continues growing, we needed to account for this lack of information as part of the CB Nano

  15. An interactive teaching device simulating intussusception reduction

    E-Print Network [OSTI]

    2010-01-01T23:59:59.000Z

    1764-x TECHNICAL INNOVATION An interactive teaching deviceIRB. We developed an interactive teaching device to simulate

  16. Anisotropic Energy Gaps of Iron-Based Superconductivity from Intraband Quasiparticle Interference in LiFeAs

    SciTech Connect (OSTI)

    Davis J. C.; Allan, M.P.; Rost, A.W.; Mackenzie, A.P.; Xie, Y.; Kihou, K.; Lee, C.H.; Iyo, A.; Eisaki, H.; Chuang, T.-M.

    2012-05-04T23:59:59.000Z

    If strong electron-electron interactions between neighboring Fe atoms mediate the Cooper pairing in iron-pnictide superconductors, then specific and distinct anisotropic superconducting energy gaps {Delta}{sub i}(k) should appear on the different electronic bands i. Here, we introduce intraband Bogoliubov quasiparticle scattering interference (QPI) techniques for determination of {Delta}{sub i}(k) in such materials, focusing on lithium iron arsenide (LiFeAs). We identify the three hole-like bands assigned previously as {gamma}, {alpha}{sub 2}, and {alpha}{sub 1}, and we determine the anisotropy, magnitude, and relative orientations of their {Delta}{sub i}(k). These measurements will advance quantitative theoretical analysis of the mechanism of Cooper pairing in iron-based superconductivity.

  17. Microbiopsy/precision cutting devices

    DOE Patents [OSTI]

    Krulevitch, P.A.; Lee, A.P.; Northrup, M.A.; Benett, W.J.

    1999-07-27T23:59:59.000Z

    Devices are disclosed for performing tissue biopsy on a small scale (microbiopsy). By reducing the size of the biopsy tool and removing only a small amount of tissue or other material in a minimally invasive manner, the risks, costs, injury and patient discomfort associated with traditional biopsy procedures can be reduced. By using micromachining and precision machining capabilities, it is possible to fabricate small biopsy/cutting devices from silicon. These devices can be used in one of four ways (1) intravascularly, (2) extravascularly, (3) by vessel puncture, and (4) externally. Additionally, the devices may be used in precision surgical cutting. 6 figs.

  18. Microbiopsy/precision cutting devices

    DOE Patents [OSTI]

    Krulevitch, Peter A. (Pleasanton, CA); Lee, Abraham P. (Walnut Creek, CA); Northrup, M. Allen (Berkeley, CA); Benett, William J. (Livermore, CA)

    1999-01-01T23:59:59.000Z

    Devices for performing tissue biopsy on a small scale (microbiopsy). By reducing the size of the biopsy tool and removing only a small amount of tissue or other material in a minimally invasive manner, the risks, costs, injury and patient discomfort associated with traditional biopsy procedures can be reduced. By using micromachining and precision machining capabilities, it is possible to fabricate small biopsy/cutting devices from silicon. These devices can be used in one of four ways 1) intravascularly, 2) extravascularly, 3) by vessel puncture, and 4) externally. Additionally, the devices may be used in precision surgical cutting.

  19. Structured wafer for device processing

    SciTech Connect (OSTI)

    Okandan, Murat; Nielson, Gregory N

    2014-11-25T23:59:59.000Z

    A structured wafer that includes through passages is used for device processing. Each of the through passages extends from or along one surface of the structured wafer and forms a pattern on a top surface area of the structured wafer. The top surface of the structured wafer is bonded to a device layer via a release layer. Devices are processed on the device layer, and are released from the structured wafer using etchant. The through passages within the structured wafer allow the etchant to access the release layer to thereby remove the release layer.

  20. Structured wafer for device processing

    DOE Patents [OSTI]

    Okandan, Murat; Nielson, Gregory N

    2014-05-20T23:59:59.000Z

    A structured wafer that includes through passages is used for device processing. Each of the through passages extends from or along one surface of the structured wafer and forms a pattern on a top surface area of the structured wafer. The top surface of the structured wafer is bonded to a device layer via a release layer. Devices are processed on the device layer, and are released from the structured wafer using etchant. The through passages within the structured wafer allow the etchant to access the release layer to thereby remove the release layer.