Sample records for wide band-gap semiconductor

  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. 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.

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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...

  19. 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.

  20. Wide-Bandgap Semiconductors

    SciTech Connect (OSTI)

    Chinthavali, M.S.

    2005-11-22T23:59:59.000Z

    With the increase in demand for more efficient, higher-power, and higher-temperature operation of power converters, design engineers face the challenge of increasing the efficiency and power density of converters [1, 2]. Development in power semiconductors is vital for achieving the design goals set by the industry. Silicon (Si) power devices have reached their theoretical limits in terms of higher-temperature and higher-power operation by virtue of the physical properties of the material. To overcome these limitations, research has focused on wide-bandgap materials such as silicon carbide (SiC), gallium nitride (GaN), and diamond because of their superior material advantages such as large bandgap, high thermal conductivity, and high critical breakdown field strength. Diamond is the ultimate material for power devices because of its greater than tenfold improvement in electrical properties compared with silicon; however, it is more suited for higher-voltage (grid level) higher-power applications based on the intrinsic properties of the material [3]. GaN and SiC power devices have similar performance improvements over Si power devices. GaN performs only slightly better than SiC. Both SiC and GaN have processing issues that need to be resolved before they can seriously challenge Si power devices; however, SiC is at a more technically advanced stage than GaN. SiC is considered to be the best transition material for future power devices before high-power diamond device technology matures. Since SiC power devices have lower losses than Si devices, SiC-based power converters are more efficient. With the high-temperature operation capability of SiC, thermal management requirements are reduced; therefore, a smaller heat sink would be sufficient. In addition, since SiC power devices can be switched at higher frequencies, smaller passive components are required in power converters. Smaller heat sinks and passive components result in higher-power-density power converters. With the advent of the use of SiC devices it is imperative that models of these be made available in commercial simulators. This enables power electronic designers to simulate their designs for various test conditions prior to fabrication. To build an accurate transistor-level model of a power electronic system such as an inverter, the first step is to characterize the semiconductor devices that are present in the system. Suitable test beds need to be built for each device to precisely test the devices and obtain relevant data that can be used for modeling. This includes careful characterization of the parasitic elements so as to emulate the test setup as closely as possible in simulations. This report is arranged as follows: Chapter 2--The testing and characterization of several diodes and power switches is presented. Chapter 3--A 55-kW hybrid inverter (Si insulated gate bipolar transistor--SiC Schottky diodes) device models and test results are presented. A detailed description of the various test setups followed by the parameter extraction, modeling, and simulation study of the inverter performance is presented. Chapter 4--A 7.5-kW all-SiC inverter (SiC junction field effect transistors (JFET)--SiC Schottky diodes) was built and tested. The models built in Saber were validated using the test data and the models were used in system applications in the Saber simulator. The simulation results and a comparison of the data from the prototype tests are discussed in this chapter. Chapter 5--The duration test results of devices utilized in buck converters undergoing reliability testing are presented.

  1. Opportunities for Wide Bandgap Semiconductor Power Electronics...

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

    Opportunities for Wide Bandgap Semiconductor Power Electronics for Hydrogen and Fuel Cell Applications Opportunities for Wide Bandgap Semiconductor Power Electronics for Hydrogen...

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

    DOE Patents [OSTI]

    Weng, Xiaojun; Goldman, Rachel S.

    2006-06-06T23:59:59.000Z

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

  3. 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

  4. 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

  5. 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.

  6. 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.

  7. Webinar: Opportunities for Wide Bandgap Semiconductor Power Electronic...

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

    Opportunities for Wide Bandgap Semiconductor Power Electronics for Hydrogen and Fuel Cell Applications Webinar: Opportunities for Wide Bandgap Semiconductor Power Electronics...

  8. 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.

  9. 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.

  10. 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.

  11. 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...

  12. 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.

  13. 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...

  14. 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 ...

  15. Sandia National Laboratories: wide-bandgap semiconductor

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

    electroluminescence was first reported by H.J. Round in 1907, and the first light-emitting diode (LED) was reported by O.V. Losev in 1927. Not until the birth of semiconductor...

  16. 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...

  17. Comparison of Wide-Bandgap Semiconductors for Power Electronics Applications

    SciTech Connect (OSTI)

    Ozpineci, B.

    2004-01-02T23:59:59.000Z

    Recent developmental advances have allowed silicon (Si) semiconductor technology to approach the theoretical limits of the Si material; however, power device requirements for many applications are at a point that the present Si-based power devices cannot handle. The requirements include higher blocking voltages, switching frequencies, efficiency, and reliability. To overcome these limitations, new semiconductor materials for power device applications are needed. For high power requirements, wide-bandgap semiconductors like silicon carbide (SiC), gallium nitride (GaN), and diamond, with their superior electrical properties, are likely candidates to replace Si in the near future. This report compares wide-bandgap semiconductors with respect to their promise and applicability for power applications and predicts the future of power device semiconductor materials.

  18. 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

  19. 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.

  20. 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 ...

  1. 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.

  2. Wide Bandgap Semiconductors: Pursuing the Promise

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilA group currentBradley NickellApril 16, 2008 TBD-0075 -In theWide Bandgap

  3. Wide Bandgap Semiconductors | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron SpinPrincetonUsingWhat is a “Shut-down”Whole AlgaeRateWhy IsWhyWhyWide

  4. 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

  5. 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

  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. 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.

  8. 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.

  9. 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.

  10. 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.

  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. 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.

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

    DOE Patents [OSTI]

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

    2008-03-18T23:59:59.000Z

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

  16. Webinar: Opportunities for Wide Bandgap Semiconductor Power Electronics for Hydrogen and Fuel Cell Applications

    Broader source: Energy.gov [DOE]

    The Energy Department will present a live webinar titled "Opportunities for Wide Bandgap Semiconductor Power Electronics for Hydrogen and Fuel Cell Applications" on Tuesday, October 21, at 12:00 p...

  17. Webinar: Opportunities for Wide Bandgap Semiconductor Power Electronics for Hydrogen and Fuel Cell Applications

    Broader source: Energy.gov [DOE]

    Recording and text version of the Fuel Cell Technologies Office webinar titled "Opportunities for Wide Bandgap Semiconductor Power Electronics for Hydrogen and Fuel Cell Applications," originally presented on October 21, 2014.

  18. 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

  19. 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

  20. 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.

  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. Photocell utilizing a wide-bandgap semiconductor material

    DOE Patents [OSTI]

    Carlson, David E. (Yardley, PA); Williams, Brown F. (Princeton, NJ)

    1984-06-05T23:59:59.000Z

    A photocell comprises a p-i-n amorphous silicon structure having a wide bandgap layer adjacent to either the p-type or n-type layer. This structure reduces the absorption of light entering the photocell and the back-diffusion of minority carriers.

  4. 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.

  5. Sandia Energy - Sandia Wide-Bandgap Semiconductor Workshop

    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 Sol Home Distribution GridDocuments HomeDatabase on EngineATeachesWide-Bandgap

  6. Science and applications of infrared semiconductor nanocrystals

    E-Print Network [OSTI]

    Geyer, Scott Mitchell

    2010-01-01T23:59:59.000Z

    In this work we study several applications of semiconductor nanocrystals (NCs) with infrared band gaps. In the first half, we explore the physics of two systems with applications in NC based photovoltaics. The physics of ...

  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. 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.

  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. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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

  15. 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.

  16. 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

  17. 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

  18. 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

  19. Reflection technique for thermal mapping of semiconductors

    DOE Patents [OSTI]

    Walter, Martin J. (Lee, NY)

    1989-06-20T23:59:59.000Z

    Semiconductors may be optically tested for their temperatures by illuminating them with tunable monochromatic electromagnetic radiation and observing the light reflected off of them. A transition point will occur when the wavelength of the light corresponds with the actual band gap energy of the semiconductor. At the transition point, the image of the semiconductor will appreciably darken as the light is transmitted through it, rather than being reflected off of it. The wavelength of the light at the transition point corresponds to the actual band gap energy and the actual temperature of the semiconductor.

  20. 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

  1. 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

  2. Semiconductor Quantum Rods as Single Molecule Fluorescent Biological Labels

    E-Print Network [OSTI]

    2006-01-01T23:59:59.000Z

    A. , Gu, W. , Larabell, C. & Alivisatos, A.P. SemiconductorHu, J.T. , Yang, W.D. & Alivisatos, A.P. Band gap variationZanchet, D. , Weiss, S. , ,Alivisatos, A. P. Synthesis and

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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...

  11. 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.

  12. Wide-bandgap semiconductors for high power, high frequency and high temperature. Materials Research Society symposium proceedings Volume 512

    SciTech Connect (OSTI)

    DenBaars, S.; Palmour, J.; Shur, M.; Spencer, M. [eds.

    1997-07-01T23:59:59.000Z

    Wide-bandgap semiconductors have a long and illustrious history, starting with the first paper on SiC light-emitting diodes published in 1907. In the last few years, however, interest in wide-bandgap semiconductors has skyrocketed. Improved material quality, important breakthroughs both in SiC and GaN technologies, and the emergence of blue GaN-based lasers, have stimulated this progress. To provide a fairly complete and up-to-date picture of this important field, most of the work presented at the conference is included in the volume. In addition, invited papers present an excellent overview of the current state of the art and offer projections for future developments. Topics include: GaN materials and devices; crystal growth; SiC materials and devices; characterization of wide-bandgap semiconductors; and processing characterization and properties of wide-bandgap materials.

  13. Conduction properties of metal/organic monolayer/semiconductor heterostructures

    SciTech Connect (OSTI)

    Li, D.; Bishop, A.; Gim, Y.; Shi, X.B.; Fitzsimmons, M.R.; Jia, Q.X. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    1998-11-01T23:59:59.000Z

    We have fabricated and characterized rectifying devices made of metal/organic monolayer/semiconductor heterostructures. The devices consist of an organic barrier layer sandwiched between an aluminum (Al) metal contact and a {ital p}-type Si semiconductor. The barrier materials were chosen from three types of self-assembled monolayers (SAMs) with different electronic properties: (1) wide-band gap poly(diallydimethyl ammonium) chloride (PDDA), (2) narrow-band gap PDDA/NiPc (nickel phthalocyanine tetrasulfonate), and (3) donor type PDDA/PPP (poly {ital p}-quaterphenylene-disulfonic-dicarboxylic acid). From current{endash}voltage (I{endash}V) measurements at room temperature, we have found the turn-on voltage of the devices can be tuned by varying the structure, hence electronic properties, of the organic monolayers, and that there exists a power-law dependence of {ital I} on V, I{proportional_to}V{sup {alpha}}, with the exponent {alpha}=2.2 for PDDA, 2.7 for PDDA/NiPc, and 1.44 for PDDA/PPP as the barrier layer, respectively. Our results imply that the transport properties are controlled by both the electronic properties of the SAMs and those of the metal and semiconductor, as indicated by the power-law dependence of the I{endash}V characteristics. {copyright} {ital 1998 American Institute of Physics.}

  14. 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

  15. System and method of modulating electrical signals using photoconductive wide bandgap semiconductors as variable resistors

    DOE Patents [OSTI]

    Harris, John Richardson; Caporaso, George J; Sampayan, Stephen E

    2013-10-22T23:59:59.000Z

    A system and method for producing modulated electrical signals. The system uses a variable resistor having a photoconductive wide bandgap semiconductor material construction whose conduction response to changes in amplitude of incident radiation is substantially linear throughout a non-saturation region to enable operation in non-avalanche mode. The system also includes a modulated radiation source, such as a modulated laser, for producing amplitude-modulated radiation with which to direct upon the variable resistor and modulate its conduction response. A voltage source and an output port, are both operably connected to the variable resistor so that an electrical signal may be produced at the output port by way of the variable resistor, either generated by activation of the variable resistor or propagating through the variable resistor. In this manner, the electrical signal is modulated by the variable resistor so as to have a waveform substantially similar to the amplitude-modulated radiation.

  16. 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.

  17. 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.

  18. 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}

  19. 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.

  20. 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.

  1. 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...

  2. 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.

  3. Searching Room Temperature Ferromagnetism in Wide Gap Semiconductors Fe-doped Strontium Titanate and Zinc Oxide

    E-Print Network [OSTI]

    Pereira, LMC; Wahl, U

    Scientic findings in the very beginning of the millennium are taking us a step further in the new paradigm of technology: spintronics. Upgrading charge-based electronics with the additional degree of freedom of the carriers spin-state, spintronics opens a path to the birth of a new generation of devices with the potential advantages of non-volatility and higher processing speed, integration densities and power efficiency. A decisive step towards this new age lies on the attribution of magnetic properties to semiconductors, the building block of today's electronics, that is, the realization of ferromagnetic semiconductors (FS) with critical temperatures above room temperature. Unfruitful search for intrinsic RT FS lead to the concept of Dilute(d) Magnetic Semiconductors (DMS): ordinary semiconductor materials where 3 d transition metals randomly substitute a few percent of the matrix cations and, by some long-range mechanism, order ferromagnetically. The times are of intense research activity and the last few ...

  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. 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

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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

  12. 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

  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. 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.

  15. Ferromagnetic semiconductors based upon AlGaP M. E. Overberg,a)

    E-Print Network [OSTI]

    Hebard, Arthur F.

    band-gap ternary InGaP, which is lattice matched to GaAs. An immediate application of the DMS, with its wide band-gap binary GaP, AlP and ternary InGaP, AlGaP, AlInP components, is used for devices

  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. 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.

  18. 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

  19. 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

  20. 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

  1. Details in Semiconductors Gordon Conference, New London, NH, August 3-8, 2008

    SciTech Connect (OSTI)

    Shengbai Zhang and Nancy Ryan Gray

    2009-09-16T23:59:59.000Z

    Continuing its tradition of excellence, this Gordon Conference will focus on research at the forefront of the field of defects in homogeneous and structured semiconductors. The conference will have a strong emphasis on the control of defects during growth and processing, with an increases emphasis on nanostructures as compared to previous conferences. Electronic, magnetic, and optical properties of bulk, thin film, and nanoscale semiconductors will be discussed in detail. In contrast to many conferences, which tend to focus on specific semiconductors, this conference deals with defects in a broad range of bulk and nanoscale electronic materials. This approach has proved to be extremely fruitful for advancing fundamental understanding in emerging materials such as wide-band-gap semiconductors, doped nanoparticles, and organic semiconductors. Presentations of state-of-the-art theoretical methods will contribute to a fundamental understanding of atomic-scale phenomena. The program consists of about twenty invited talks, with plenty of discussion time, and a number of contributed poster sessions. Because of the large amount of discussion time, the conference provides an ideal forum for dealing with topics that are new and/or controversial.

  2. Lattice matched semiconductor growth on crystalline metallic substrates

    DOE Patents [OSTI]

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

    2013-11-05T23:59:59.000Z

    Methods of fabricating a semiconductor layer or device and said devices are disclosed. The methods include but are not limited to providing a metal or metal alloy substrate having a crystalline surface with a known lattice parameter (a). The methods further include growing a crystalline semiconductor alloy layer on the crystalline substrate surface by coincident site lattice matched epitaxy. The semiconductor layer may be grown without any buffer layer between the alloy and the crystalline surface of the substrate. The semiconductor alloy may be prepared to have a lattice parameter (a') that is related to the lattice parameter (a). The semiconductor alloy may further be prepared to have a selected band gap.

  3. 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.

  4. 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.

  5. 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.

  6. Differential method of analysis of luminescence spectra of semiconductors

    SciTech Connect (OSTI)

    Emel'yanov, A. M., E-mail: Emelyanov@mail.ioffe.ru [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation)

    2010-09-15T23:59:59.000Z

    A method for analyzing the luminescence spectra of semiconductors is suggested. The method is based on differentiation of the spectra. The potentialities of the method are demonstrated for luminescence in the region of the fundamental absorption edge of Si and SiGe alloy single crystals. The method is superior in accuracy to previously known luminescence methods of determining the band gap of indirect-gap semiconductors and practically insensitive to different conditions of outputting radiation from the sample.

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

    SciTech Connect (OSTI)

    Lyons, J. L.; Janotti, A.; Van de Walle, C. G. [Materials Department, University of California, Santa Barbara, California 93106-5050 (United States)

    2014-01-07T23:59:59.000Z

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

  8. Hydrogen local vibrational modes in semiconductors

    SciTech Connect (OSTI)

    McCluskey, M D [Univ. of California, Berkeley, CA (United States). Dept. of Physics

    1997-06-01T23:59:59.000Z

    Following, a review of experimental techniques, theory, and previous work, the results of local vibrational mode (LVM) spectroscopy on hydrogen-related complexes in several different semiconductors are discussed. Hydrogen is introduced either by annealing in a hydrogen ambient. exposure to a hydrogen plasma, or during growth. The hydrogen passivates donors and acceptors in semiconductors, forming neutral complexes. When deuterium is substituted for hydrogen. the frequency of the LVM decreases by approximately the square root of two. By varying the temperature and pressure of the samples, the microscopic structures of hydrogen-related complexes are determined. For group II acceptor-hydrogen complexes in GaAs, InP, and GaP, hydrogen binds to the host anion in a bond-centered orientation, along the [111] direction, adjacent to the acceptor. The temperature dependent shift of the LVMs are proportional to the lattice thermal energy U(T), a consequence of anharmonic coupling between the LVM and acoustical phonons. In the wide band gap semiconductor ZnSe, epilayers grown by metalorganic chemical vapor phase epitaxy (MOCVD) and doped with As form As-H complexes. The hydrogen assumes a bond-centered orientation, adjacent to a host Zn. In AlSb, the DX centers Se and Te are passivated by hydrogen. The second, third, and fourth harmonics of the wag modes are observed. Although the Se-D complex has only one stretch mode, the Se-H stretch mode splits into three peaks. The anomalous splitting is explained by a new interaction between the stretch LVM and multi-phonon modes of the lattice. As the temperature or pressure is varied, and anti-crossing is observed between LVM and phonon modes.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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

  17. Epitaxial growth of 100-?m thick M-type hexaferrite crystals on wide bandgap semiconductor GaN/Al{sub 2}O{sub 3} substrates

    SciTech Connect (OSTI)

    Hu, Bolin; Su, Zhijuan; Bennett, Steve; Chen, Yajie, E-mail: y.chen@neu.edu; Harris, Vincent G. [Center for Microwave Magnetic Materials and Integrated Circuits and Department of Electrical and Computer Engineering, Northeastern University, Boston, Massachusetts 02115 (United States)

    2014-05-07T23:59:59.000Z

    Thick barium hexaferrite BaFe{sub 12}O{sub 19} (BaM) films having thicknesses of ?100??m were epitaxially grown on GaN/Al{sub 2}O{sub 3} substrates from a molten-salt solution by vaporizing the solvent. X-ray diffraction measurement verified the growth of BaM (001) textured growth of thick films. Saturation magnetization, 4?M{sub s}, was measured for as-grown films to be 4.6 ± 0.2 kG and ferromagnetic resonance measurements revealed a microwave linewidth of ?100?Oe at X-band. Scanning electron microscopy indicated clear hexagonal crystals distributed on the semiconductor substrate. These results demonstrate feasibility of growing M-type hexaferrite crystal films on wide bandgap semiconductor substrates by using a simple powder melting method. It also presents a potential pathway for the integration of ferrite microwave passive devices with active semiconductor circuit elements creating system-on-a-wafer architectures.

  18. 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.

  19. 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

  20. Interaction of wide-band-gap single crystals with 248-nm excimer laser radiation. XI. The effect of water vapor and temperature on laser desorption

    E-Print Network [OSTI]

    Dickinson, J. Thomas

    . Significantly, introducing water vapor lowers the particle velocities and thus the effective surface temperature systems, simultaneous electronic excitation and exposure to aggressive chemicals can acceler- ate etching-induced neutral particle desorption and surface erosion on single- crystal sodium chloride in the presence of low

  1. 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.

  2. 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

  3. 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.

  4. 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}.

  5. 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.

  6. 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.

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Isotopically controlled semiconductors

    E-Print Network [OSTI]

    Haller, Eugene E.

    2006-01-01T23:59:59.000Z

    16 Isotopically Controlled Semiconductors Eugene E. Hallerof isotopically engineered semiconductors; for outstandingisotopically controlled semiconductor crystals. This article

  17. 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.

  18. 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.

  19. 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.

  20. Iron oxidation state of FeTiO3 under high pressure X. Wu,1,* G. Steinle-Neumann,1 O. Narygina,1 I. Kantor,1,2 C. McCammon,1 S. Pascarelli,3 G. Aquilanti,3 V. Prakapenka,2

    E-Print Network [OSTI]

    Steinle-Neumann, Gerd

    the oxygen bridge in the adjacent octahedral, then decreases at higher pressure due to the ilmenite in the materials and earth sci- ences. Ilmenite is a wide-band-gap semiconductor with a 2.5 eV band gap,1 which

  1. 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.

  2. Interaction of wide-band-gap single crystals with 248-nm excimer laser irradiation. X. Laser-induced near-surface absorption in single-crystal NaCl

    E-Print Network [OSTI]

    Dickinson, J. Thomas

    are expected to play an important role in optical break- down and surface damage. II. EXPERIMENT The results of a few thousand kelvin even in the absence of visible surface damage. The origin of the laser absorption radiation. As much as 20% of the incident radiation at 248 nm must be absorbed in the near-surface region

  3. SEMICONDUCTOR DETECTORS - AN INTRODUCTION

    E-Print Network [OSTI]

    Goulding, F.S.

    2011-01-01T23:59:59.000Z

    infrinfc primely owned dtfiw. SEMICONDUCTOR DETECTORS - ANi) LBL-7282 I. History Semiconductor detectors appeared onof alpha particles by semiconductor diodes several years

  4. Isotopically controlled semiconductors

    E-Print Network [OSTI]

    Haller, E.E.

    2004-01-01T23:59:59.000Z

    and phonons in semiconductors,” J. Non-Cryst. Solids 141 (LVM) Spectroscopy of Semiconductors,” Mat. Res. Soc. Symp.Isotopically Engineered Semiconductors – New Media for the

  5. Isotopically controlled semiconductors

    E-Print Network [OSTI]

    Haller, Eugene E.

    2001-01-01T23:59:59.000Z

    Transmutation Doping of Semiconductor Materials, NationalTransmutation Doping of Semiconductor Materials, NationalProperties of Doped Semiconductors , Solid State Series,

  6. Semiconductor Nanowires: What's Next?

    E-Print Network [OSTI]

    Yang, Peidong

    2011-01-01T23:59:59.000Z

    Semiconductor nanowires, what’s next? Peidong Yang, Ruoxuelater research into semiconductor whiskers with nanoscalewere popularized as semiconductor nanowires in the following

  7. Opportunities for Wide Bandgap Semiconductor Power Electronics...

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

    - Partial Listing of Copyright 2014, Cree Inc. pg. 14 1200V SiC MOSFET design wins in PV inverters 1200V, 80m SiC MOSFETs have been selected by Japan's Sanix Inc. 9.9kW...

  8. INFOGRAPHIC: Wide Bandgap Semiconductors | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742Energy ChinaofSchaefer To:Department ofOral TestimonyEnergyFinding U.INDIANAPOLISINFOGRAPHIC:

  9. INFOGRAPHIC: Wide Bandgap Semiconductors | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't YourTransport(Fact Sheet), GeothermalGridHYDROGEND DTechnologiesFindingThe Road to

  10. Optical properties of two-dimensional transition metal dichalcogenides

    E-Print Network [OSTI]

    Lin, Yuxuan, S.M. Massachusetts Institute of Technology

    2014-01-01T23:59:59.000Z

    The re-discovery of the atomically thin transition metal dichalcogenides (TMDs), which are mostly semiconductors with a wide range of band gaps, has diversified the family of two-dimensional materials and boosted the ...

  11. Celebrating Faculty Excellence acclaiming the awards, honors,

    E-Print Network [OSTI]

    of the world's foremost experts on doping wide band-gap semiconductors, creating blue and ultraviolet light-emitting diodes (leds) and lasers that have led to improved consumer products, including sharper laser printers

  12. Stretchable semiconductor elements and stretchable electrical circuits

    DOE Patents [OSTI]

    Rogers, John A. (Champaign, IL); Khang, Dahl-Young (Seoul, KR); Menard, Etienne (Durham, NC)

    2009-07-07T23:59:59.000Z

    The invention provides methods and devices for fabricating printable semiconductor elements and assembling printable semiconductor elements onto substrate surfaces. Methods, devices and device components of the present invention are capable of generating a wide range of flexible electronic and optoelectronic devices and arrays of devices on substrates comprising polymeric materials. The present invention also provides stretchable semiconductor structures and stretchable electronic devices capable of good performance in stretched configurations.

  13. 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.

  14. 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.

  15. Semiconductor Ion Implanters

    SciTech Connect (OSTI)

    MacKinnon, Barry A. [Isys, 2727 Walsh Ave., Suite 103, Santa Clara, CA 95051 (United States); Ruffell, John P. [Group 3, LLC, Sunnyvale, CA 94086 (United States)

    2011-06-01T23:59:59.000Z

    In 1953 the Raytheon CK722 transistor was priced at $7.60. Based upon this, an Intel Xeon Quad Core processor containing 820,000,000 transistors should list at $6.2 billion. Particle accelerator technology plays an important part in the remarkable story of why that Intel product can be purchased today for a few hundred dollars. Most people of the mid twentieth century would be astonished at the ubiquity of semiconductors in the products we now buy and use every day. Though relatively expensive in the nineteen fifties they now exist in a wide range of items from high-end multicore microprocessors like the Intel product to disposable items containing 'only' hundreds or thousands like RFID chips and talking greeting cards. This historical development has been fueled by continuous advancement of the several individual technologies involved in the production of semiconductor devices including Ion Implantation and the charged particle beamlines at the heart of implant machines. In the course of its 40 year development, the worldwide implanter industry has reached annual sales levels around $2B, installed thousands of dedicated machines and directly employs thousands of workers. It represents in all these measures, as much and possibly more than any other industrial application of particle accelerator technology. This presentation discusses the history of implanter development. It touches on some of the people involved and on some of the developmental changes and challenges imposed as the requirements of the semiconductor industry evolved.

  16. DOE Announces Webinars on Zero Energy Ready Homes, Wide Bandgap...

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

    on Opportunities for Wide Bandgap Semiconductor Power Electronics for Hydrogen and Fuel Cell Applications Webinar Sponsor: Fuel Cell Technologies Office The Energy...

  17. Wafer-fused semiconductor radiation detector

    DOE Patents [OSTI]

    Lee, Edwin Y. (Livermore, CA); James, Ralph B. (Livermore, CA)

    2002-01-01T23:59:59.000Z

    Wafer-fused semiconductor radiation detector useful for gamma-ray and x-ray spectrometers and imaging systems. The detector is fabricated using wafer fusion to insert an electrically conductive grid, typically comprising a metal, between two solid semiconductor pieces, one having a cathode (negative electrode) and the other having an anode (positive electrode). The wafer fused semiconductor radiation detector functions like the commonly used Frisch grid radiation detector, in which an electrically conductive grid is inserted in high vacuum between the cathode and the anode. The wafer-fused semiconductor radiation detector can be fabricated using the same or two different semiconductor materials of different sizes and of the same or different thicknesses; and it may utilize a wide range of metals, or other electrically conducting materials, to form the grid, to optimize the detector performance, without being constrained by structural dissimilarity of the individual parts. The wafer-fused detector is basically formed, for example, by etching spaced grooves across one end of one of two pieces of semiconductor materials, partially filling the grooves with a selected electrical conductor which forms a grid electrode, and then fusing the grooved end of the one semiconductor piece to an end of the other semiconductor piece with a cathode and an anode being formed on opposite ends of the semiconductor pieces.

  18. Life-cycle Assessment of Semiconductors

    E-Print Network [OSTI]

    Boyd, Sarah B.

    2009-01-01T23:59:59.000Z

    SemiconductorThe Semiconductor Industry: Size, Growth andSemiconductor Life-cycle Environmental Impacts . . . . . . .

  19. Wide Bandgap Extrinsic Photoconductive Switches

    SciTech Connect (OSTI)

    Sullivan, J S

    2012-01-17T23:59:59.000Z

    Photoconductive semiconductor switches (PCSS) have been investigated since the late 1970s. Some devices have been developed that withstand tens of kilovolts and others that switch hundreds of amperes. However, no single device has been developed that can reliably withstand both high voltage and switch high current. Yet, photoconductive switches still hold the promise of reliable high voltage and high current operation with subnanosecond risetimes. Particularly since good quality, bulk, single crystal, wide bandgap semiconductor materials have recently become available. In this chapter we will review the basic operation of PCSS devices, status of PCSS devices and properties of the wide bandgap semiconductors 4H-SiC, 6H-SiC and 2H-GaN.

  20. Hydrogen in semiconductors and insulators

    E-Print Network [OSTI]

    Van de Walle, Chris G.

    2007-01-01T23:59:59.000Z

    level in two different semiconductors, illustrating the06-01999R1 Hydrogen in semiconductors and insulators SpecialA. oxide materials; A. semiconductors; C. electronic

  1. Infrared spectroscopy of novel semiconductors /

    E-Print Network [OSTI]

    Chapler, Brian Caleb

    2014-01-01T23:59:59.000Z

    dilute magnetic semiconductor . . . . . . . . 1 1.1.1in the topological semiconductors Bi2Te3 and Mn—dopedM. Fundamentals of semiconductors. Springer-Verlag, Berlin,

  2. Novel room temperature ferromagnetic semiconductors

    E-Print Network [OSTI]

    Gupta, Amita

    2004-01-01T23:59:59.000Z

    Spin Related Phenomena in Semiconductors, (27-28 Jan 1997,FERROMAGNETIC SEMICONDUCTORS Amita Gupta Stockholm, Junedata are processed by semiconductor chips, and stored in the

  3. High-field electroluminescence in semiconductor tunnel junctions with a Mn-doped GaAs layer

    SciTech Connect (OSTI)

    Hai, Pham Nam [Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-0033 (Japan); Yatsui, Takashi; Ohtsu, Motoichi; Tanaka, Masaaki [Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Nanophotonics Research Center, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

    2014-09-21T23:59:59.000Z

    We investigated high-field electroluminescence (EL) in semiconductor tunnel junctions with a Mn-doped GaAs layer (here, referred to as GaAs:Mn). Besides the band-gap emission of GaAs, the EL spectra show visible light emissions with two peaks at 1.94?eV and 2.19?eV, which are caused by d-d transitions of the Mn atoms excited by hot electrons. The threshold voltages for band-gap and visible light EL in the tunnel junctions with a GaAs:Mn electrode are 1.3?V higher than those of GaAs:Mn excited by hot holes in reserve biased p{sup +}-n junctions, which is consistent with the hot carrier transport in the band profiles of these structures. Our EL results at room temperature show that the electron temperature in GaAs:Mn can be as high as ?700?K for a low input electrical power density of 0.4?W/cm{sup 2}, while the lattice temperature of the GaAs:Mn layer can be kept at 340?K.

  4. Methods and devices for fabricating and assembling printable semiconductor elements

    DOE Patents [OSTI]

    Nuzzo, Ralph G. (Champaign, IL); Rogers, John A. (Champaign, IL); Menard, Etienne (Urbana, IL); Lee, Keon Jae (Savoy, IL); Khang, Dahl-Young (Urbana, IL); Sun, Yugang (Champaign, IL); Meitl, Matthew (Champaign, IL); Zhu, Zhengtao (Urbana, IL)

    2009-11-24T23:59:59.000Z

    The invention provides methods and devices for fabricating printable semiconductor elements and assembling printable semiconductor elements onto substrate surfaces. Methods, devices and device components of the present invention are capable of generating a wide range of flexible electronic and optoelectronic devices and arrays of devices on substrates comprising polymeric materials. The present invention also provides stretchable semiconductor structures and stretchable electronic devices capable of good performance in stretched configurations.

  5. Methods and devices for fabricating and assembling printable semiconductor elements

    DOE Patents [OSTI]

    Nuzzo, Ralph G; Rogers, John A; Menard, Etienne; Lee, Keon Jae; Khang, Dahl-Young; Sun, Yugang; Meitl, Matthew; Zhu, Zhengtao

    2014-03-04T23:59:59.000Z

    The invention provides methods and devices for fabricating printable semiconductor elements and assembling printable semiconductor elements onto substrate surfaces. Methods, devices and device components of the present invention are capable of generating a wide range of flexible electronic and optoelectronic devices and arrays of devices on substrates comprising polymeric materials. The present invention also provides stretchable semiconductor structures and stretchable electronic devices capable of good performance in stretched configurations.

  6. Methods and devices for fabricating and assembling printable semiconductor elements

    DOE Patents [OSTI]

    Nuzzo, Ralph G; Rogers, John A; Menard, Etienne; Lee, Keon Jae; Khang, Dahl-Young; Sun, Yugang; Meitl, Matthew; Zhu, Zhengtao

    2013-05-14T23:59:59.000Z

    The invention provides methods and devices for fabricating printable semiconductor elements and assembling printable semiconductor elements onto substrate surfaces. Methods, devices and device components of the present invention are capable of generating a wide range of flexible electronic and optoelectronic devices and arrays of devices on substrates comprising polymeric materials. The present invention also provides stretchable semiconductor structures and stretchable electronic devices capable of good performance in stretched configurations.

  7. Methods and devices for fabricating and assembling printable semiconductor elements

    DOE Patents [OSTI]

    Nuzzo, Ralph G. (Champaign, IL); Rogers, John A. (Champaign, IL); Menard, Etienne (Durham, NC); Lee, Keon Jae (Daejeon, KR); Khang, Dahl-Young (Urbana, IL); Sun, Yugang (Champaign, IL); Meitl, Matthew (Raleigh, NC); Zhu, Zhengtao (Urbana, IL)

    2011-07-19T23:59:59.000Z

    The invention provides methods and devices for fabricating printable semiconductor elements and assembling printable semiconductor elements onto substrate surfaces. Methods, devices and device components of the present invention are capable of generating a wide range of flexible electronic and optoelectronic devices and arrays of devices on substrates comprising polymeric materials. The present invention also provides stretchable semiconductor structures and stretchable electronic devices capable of good performance in stretched configurations.

  8. Mixed semiconductor nanocrystal compositions

    DOE Patents [OSTI]

    Maskaly, Garry R. (Los Alamos, NM); Schaller, Richard D. (Santa Fe, NM); Klimov, Victor I. (Los Alamos, NM)

    2011-02-15T23:59:59.000Z

    Composition comprising one or more energy donors and one or more energy acceptors, wherein energy is transferred from the energy donor to the energy acceptor and wherein: the energy acceptor is a colloidal nanocrystal having a lower band gap energy than the energy donor; the energy donor and the energy acceptor are separated by a distance of 40 nm or less; wherein the average peak absorption energy of the acceptor is at least 20 meV greater than the average peak emission energy of the energy donor; and wherein the ratio of the number of energy donors to the number of energy acceptors is from about 2:1 to about 1000:1.

  9. 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.

  10. 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.}

  11. Mismatched semiconductor nanowires: growth and characterization

    E-Print Network [OSTI]

    Yim, Joanne Wing Lan

    2011-01-01T23:59:59.000Z

    SemiconductorFundamentals of Semiconductors: Physics and MaterialsDilute III-V Nitride Semiconductors and Material Systems (

  12. Beam excited acoustic instability in semiconductor quantum plasmas

    SciTech Connect (OSTI)

    Rasheed, A.; Siddique, M.; Huda, F. [Department of Physics, Government College University, Faisalabad 38000 (Pakistan); Jamil, M. [Department of Physics, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Jung, Y.-D. [Department of Applied Physics and Department of Bionanotechnology, Hanyang University, Ansan, Kyunggi-Do 426-791 (Korea, Republic of)

    2014-06-15T23:59:59.000Z

    The instability of hole-Acoustic waves due to electron beam in semiconductor quantum plasmas is examined using the quantum hydrodynamic model. The quantum effects are considered including Bohm potential, Fermi degenerate pressure, and exchange potential of the semiconductor quantum plasma species. Our model is applied to nano-sized GaAs semiconductor plasmas. The variation of the growth rate of the unstable mode is obtained over a wide range of system parameters. It is found that the thermal effects of semiconductor species have significance over the hole-Acoustic waves.

  13. Fabrication of stable, wide-bandgap thin films of Mg, Zn and O

    DOE Patents [OSTI]

    Katiyar, Ram S.; Bhattacharya, Pijush; Das, Rasmi R.

    2006-07-25T23:59:59.000Z

    A stable, wide-bandgap (approximately 6 eV) ZnO/MgO multilayer thin film is fabricated using pulsed-laser deposition on c-plane Al2O3 substrates. Layers of ZnO alternate with layers of MgO. The thickness of MgO is a constant of approximately 1 nm; the thicknesses of ZnO layers vary from approximately 0.75 to 2.5 nm. Abrupt structural transitions from hexagonal to cubic phase follow a decrease in the thickness of ZnO sublayers within this range. The band gap of the thin films is also influenced by the crystalline structure of multilayer stacks. Thin films with hexagonal and cubic structure have band-gap values of 3.5 and 6 eV, respectively. In the hexagonal phase, Mg content of the films is approximately 40%; in the cubic phase Mg content is approximately 60%. The thin films are stable and their structural and optical properties are unaffected by annealing at 750.degree. C.

  14. Congrs SFC-EuroChem Universit Henri

    E-Print Network [OSTI]

    not energetically possible with insulators. More specifically, an excited sensitizer, electron to the semiconductor of binding a molecular system to nanocrystalline wide band-gap semiconductors, of new types of electrochromic of solar energy conversion and of optical memor devices. Recent advances in the design of new electron

  15. 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.

  16. Semiconductor bridge (SCB) detonator

    DOE Patents [OSTI]

    Bickes, R.W. Jr.; Grubelich, M.C.

    1999-01-19T23:59:59.000Z

    The present invention is a low-energy detonator for high-density secondary-explosive materials initiated by a semiconductor bridge (SCB) igniter that comprises a pair of electrically conductive lands connected by a semiconductor bridge. The semiconductor bridge is in operational or direct contact with the explosive material, whereby current flowing through the semiconductor bridge causes initiation of the explosive material. Header wires connected to the electrically-conductive lands and electrical feed-throughs of the header posts of explosive devices, are substantially coaxial to the direction of current flow through the SCB, i.e., substantially coaxial to the SCB length. 3 figs.

  17. Semiconductor bridge (SCB) detonator

    DOE Patents [OSTI]

    Bickes, Jr., Robert W. (Albuquerque, NM); Grubelich, Mark C. (Albuquerque, NM)

    1999-01-01T23:59:59.000Z

    The present invention is a low-energy detonator for high-density secondary-explosive materials initiated by a semiconductor bridge igniter that comprises a pair of electrically conductive lands connected by a semiconductor bridge. The semiconductor bridge is in operational or direct contact with the explosive material, whereby current flowing through the semiconductor bridge causes initiation of the explosive material. Header wires connected to the electrically-conductive lands and electrical feed-throughs of the header posts of explosive devices, are substantially coaxial to the direction of current flow through the SCB, i.e., substantially coaxial to the SCB length.

  18. First principles study of Fe in diamond: A diamond-based half metallic dilute magnetic semiconductor

    SciTech Connect (OSTI)

    Benecha, E. M. [Department of Physics, University of South Africa, P.O. Box 392, UNISA 0003 Pretoria (South Africa); Lombardi, E. B., E-mail: lombaeb@unisa.ac.za [College of Graduate Studies, University of South Africa, P.O. Box 392, UNISA 0003 Pretoria (South Africa)

    2013-12-14T23:59:59.000Z

    Half-metallic ferromagnetic ordering in semiconductors, essential in the emerging field of spintronics for injection and transport of highly spin polarised currents, has up to now been considered mainly in III–V and II–VI materials. However, low Curie temperatures have limited implementation in room temperature device applications. We report ab initio Density Functional Theory calculations on the properties of Fe in diamond, considering the effects of lattice site, charge state, and Fermi level position. We show that the lattice sites and induced magnetic moments of Fe in diamond depend strongly on the Fermi level position and type of diamond co-doping, with Fe being energetically most favorable at the substitutional site in p-type and intrinsic diamond, while it is most stable at a divacancy site in n-type diamond. Fe induces spin polarized bands in the band gap, with strong hybridization between Fe-3d and C-2s,2p bands. We further consider Fe-Fe spin interactions in diamond and show that substitutional Fe{sup +1} in p-type diamond exhibits a half-metallic character, with a magnetic moment of 1.0??{sub B} per Fe atom and a large ferromagnetic stabilization energy of 33?meV, an order of magnitude larger than in other semiconductors, with correspondingly high Curie temperatures. These results, combined with diamond's unique properties, demonstrate that Fe doped p-type diamond is likely to be a highly suitable candidate material for spintronics applications.

  19. Features of the band structure and conduction mechanisms in the n-HfNiSn semiconductor heavily doped with Ru

    SciTech Connect (OSTI)

    Romaka, V. A., E-mail: vromaka@polynet.lviv.ua [National Academy of Sciences of Ukraine, Pidstrygach Institute for Applied Problems in Mechanics and Mathematics (Ukraine); Rogl, P. [Universität Wien, Institut für Physikalische Chemie (Austria); Romaka, V. V. [National University Lvivska Politekhnika (Ukraine); Stadnyk, Yu. V. [Ivan Franko National University of Lviv (Ukraine); Korzh, R. O.; Krayovskyy, V. Ya. [National University Lvivska Politekhnika (Ukraine); Horyn, A. M. [Ivan Franko National University of Lviv (Ukraine)

    2014-12-15T23:59:59.000Z

    The crystal and electronic structure and energy and kinetic properties of the n-HfNiSn semiconductor heavily doped with a Ru acceptor impurity are investigated in the temperature and Ru concentration ranges T = 80–400 K and N{sub A}{sup Ru} ? 9.5 × 10{sup 19}?5.7 × 10{sup 20} cm{sup ?3} (x = 0–0.03), respectively. The mechanism of structural-defect generation is established, which changes the band gap and degree of compensation of the semiconductor and consists in the simultaneous concentration reduction and elimination of donor structural defects by means of the displacement of ?1% of Ni atoms from the Hf (4a) positions, the generation of acceptor structural defects upon the substitution of Ru atoms for Ni atoms in the 4c positions, and the generation of donor defects in the form of vacancies in the Sn (4b) positions. The calculated electronic structure of HfNi{sub 1?x}Ru{sub x}Sn is consistent with the experiment. The results obtained are discussed within the Shklovsky-Efros model for a heavily doped and compensated semiconductor.

  20. Chemical dynamics and bonding at gas/semiconductor and oxide/semiconductor interfaces

    E-Print Network [OSTI]

    Bishop, Sarah R.

    2010-01-01T23:59:59.000Z

    applied to alternative semiconductor materials to determinephase oxides and semiconductor surfaces. Both experimentalunderstanding of the oxide/semiconductor interface. The

  1. REVIEW ARTICLE Semiconductor quantum dot-sensitized

    E-Print Network [OSTI]

    Cao, Guozhong

    of low-cost and high-performance solar cells for sustainable energy sources to re- place fossil fuels has) fabrication methods of QDs, and 4) nanocrystalline photoelectrodes for solar cells. We also make suggestions band gap depending on the QD size, 2) a larger extinction coefficient, 3) higher stability toward water

  2. SSSSSSSS LLLLSemiconductor System LabSemiconductor System LabSemiconductor System LabSemiconductor System Lab Jaeseo Lee, Gigabit Optical Interface IC Design 1

    E-Print Network [OSTI]

    Yoo, Hoi-Jun

    range Wide Bandwidth Low Noise amplifier is required!! 60~80dB 1) providing dc level restoration 2Semiconductor System Lab Design Goal · Gain range : 60~80dB (1k ~ 10k) · Wide bandwidth · Low Noise · CMOS · Motivation · Transimpedance Amplifier (TIA) ­ Why TIA? ­ Noise Source ­ TIA Noise & Design Solution

  3. Mesoscopic pointlike defects in semiconductors: Deep-level energies D. D. Nolte

    E-Print Network [OSTI]

    Nolte, David D.

    -semiconductor heterostructures to include metal-semiconductor,1 insulator-semiconductor, and superconductor-semiconductor

  4. Semiconductor Engineers in a Global Economy

    E-Print Network [OSTI]

    Brown, Clair; Linden, Greg

    2007-01-01T23:59:59.000Z

    Technology: The Case of Semiconductors. Brookings Institute:Society, Space, and Semiconductors in The Restructuring Ofin the Global Semiconductor Industry. ” California

  5. Synthesis and Characterization of Mesoporous Semiconductors

    E-Print Network [OSTI]

    Kang, Chris Byung-hwa

    2012-01-01T23:59:59.000Z

    Brock, S. L. “Porous semiconductor chalcogenide aerogels. ”Nanostructured Semiconductor. ” J. Am. Chem. Soc. , 127,in mesostructured semiconductors based on the [SnSe 4 ]4-

  6. Semiconductor Nanowires and Nanotubes for Energy Conversion

    E-Print Network [OSTI]

    Fardy, Melissa Anne

    2010-01-01T23:59:59.000Z

    Thermoelectricity in semiconductor nanostructures. Science,splitting using semiconductor electrodes. InternationalChalcogenides, Monographs in Semiconductor Physics, ed. L.S.

  7. Webinar October 21: Opportunities for Wide Bandgap Semiconductor...

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

    Fuel Cell Applications" on Tuesday, October 21, from 12:00 p.m. to 1:00 p.m. Eastern Daylight Time. Numerous applications of hydrogen and fuel cell technologies could benefit from...

  8. Wide Bandgap Semiconductors for Power Electronics, Optoelectronics, and Advanced Communications

    E-Print Network [OSTI]

    Li, Mo

    for hybrid and electric vehicles, solar photovoltaic inverters, power supply miniaturization and efficiency reliability and efficiency. Georgia Tech also has leading expertise in the metrology of the temperature and stresses in GaN electronics to verify device performance and yield new insight into device reliability

  9. Wide Bandgap Semiconductors for Clean Energy Workshop | Department of

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilA group currentBradley NickellApril 16, 2008 TBD-0075 -In the

  10. Opportunities for Wide Bandgap Semiconductor Power Electronics for Hydrogen

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page onYouTube YouTube Note: Since the.pdfBreaking ofOilNEWResponse toOctober 2014Funds forEnergyOperationsEnergyand

  11. Wide Bandgap Semiconductors: Essential to Our Technology Future |

    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

  12. Wide Bandgap Semiconductors: Pursuing the Promise | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742Energy China 2015ofDepartment of EnergyThe U.S. DepartmentEnergy WASHINGTON,Concept

  13. Wide Bandgap Semiconductors for Clean Energy Workshop Agenda

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your DensityEnergy U.S.-China Electric VehicleCenters | Department ofofto PurchaseApril 16,WhoWhy AreWhyPower

  14. Wide Bandgap Semiconductors for Clean Energy Workshop: Summary Report

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your DensityEnergy U.S.-China Electric VehicleCenters | Department ofofto PurchaseApril 16,WhoWhy

  15. Webinar October 21: Opportunities for Wide Bandgap Semiconductor Power

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page onYouTube YouTube Note: SinceDevelopment | Department ofPartnerships ToolkitWaste Heat Wasteof|WebinarElectronics for

  16. Interpretation of the Phonon Frequency Shifts in ZnO Quantum Dots Khan A. Alim, Vladimir A. Fonoberov, and Alexander A. Balandin

    E-Print Network [OSTI]

    Fonoberov, Vladimir

    made of zinc oxide (ZnO), a wide-bandgap semiconductor, have recently attracted attention due Zinc oxide (ZnO) presents interesting material system because of its wide band gap of 3.37 eV and some ultraviolet (UV) protection films, gas sensors, and varistors. Raman spectroscopy presents a powerful tool

  17. Thermal Conductivity of Ordered Mesoporous Titania Films Made from Nanocrystalline Building Blocks and Sol-Gel Reagents

    E-Print Network [OSTI]

    Pilon, Laurent

    significant attention due to their wide range of applications. They have been used in dye-sensitized solar cells for their wide band gap semiconductor properties.1 They have also been considered for solid oxide fuel cells as high proton conductivity porous exchange membranes.2 Mesoporous TiO2 is also a very

  18. Broad-area tandem semiconductor laser

    SciTech Connect (OSTI)

    Chen, T.R.; Mehuys, D.; Zhuang, Y.H.; Mittelstein, M.; Wang, H.; Derry, P.L.; Kajanto, M.; Yariv, A.

    1988-10-17T23:59:59.000Z

    A tandem combination of a uniform gain broad-area semiconductor laser and a (lateral) periodic gain section displays a stable, near-diffraction-limited single-lobed far-field pattern. The GaAs/GaAlAs quantum well lasers display a high degree of coherence across 60-..mu..m-wide apertures provided that the broad-area section is sufficiently long.

  19. Blasting detonators incorporating semiconductor bridge technology

    SciTech Connect (OSTI)

    Bickes, R.W. Jr.

    1994-05-01T23:59:59.000Z

    The enormity of the coal mine and extraction industries in Russia and the obvious need in both Russia and the US for cost savings and enhanced safety in those industries suggests that joint studies and research would be of mutual benefit. The author suggests that mine sites and well platforms in Russia offer an excellent opportunity for the testing of Sandia`s precise time-delay semiconductor bridge detonators, with the potential for commercialization of the detonators for Russian and other world markets by both US and Russian companies. Sandia`s semiconductor bridge is generating interest among the blasting, mining and perforation industries. The semiconductor bridge is approximately 100 microns long, 380 microns wide and 2 microns thick. The input energy required for semiconductor bridge ignition is one-tenth the energy required for conventional bridgewire devices. Because semiconductor bridge processing is compatible with other microcircuit processing, timing and logic circuits can be incorporated onto the chip with the bridge. These circuits can provide for the precise timing demanded for cast effecting blasting. Indeed tests by Martin Marietta and computer studies by Sandia have shown that such precise timing provides for more uniform rock fragmentation, less fly rock, reduce4d ground shock, fewer ground contaminants and less dust. Cost studies have revealed that the use of precisely timed semiconductor bridges can provide a savings of $200,000 per site per year. In addition to Russia`s vast mineral resources, the Russian Mining Institute outside Moscow has had significant programs in rock fragmentation for many years. He anticipated that collaborative studies by the Institute and Sandia`s modellers would be a valuable resource for field studies.

  20. Method of doping a semiconductor

    DOE Patents [OSTI]

    Yang, Chiang Y. (Miller Place, NY); Rapp, Robert A. (Columbus, OH)

    1983-01-01T23:59:59.000Z

    A method for doping semiconductor material. An interface is established between a solid electrolyte and a semiconductor to be doped. The electrolyte is chosen to be an ionic conductor of the selected impurity and the semiconductor material and electrolyte are jointly chosen so that any compound formed from the impurity and the semiconductor will have a free energy no lower than the electrolyte. A potential is then established across the interface so as to allow the impurity ions to diffuse into the semiconductor. In one embodiment the semiconductor and electrolyte may be heated so as to increase the diffusion coefficient.

  1. 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 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%.

  2. 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 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%.

  3. Structure and electronic properties features of amorphous chalhogenide semiconductor films prepared by ion-plasma spraying

    SciTech Connect (OSTI)

    Korobova, N., E-mail: korobova3@mail.ru; Timoshenkov, S. [Department of Microelectronics, National Research University of Electronic Technology (MIET), Zelenograd (Russian Federation); Almasov, N.; Prikhodko, O. [al-Farabi Kazakh National University, Almaty (Kazakhstan); Tsendin, K. [Ioffe Physical-Technical Institute, Russian Academy of Sciences, St. Petersburg (Russian Federation)

    2014-10-21T23:59:59.000Z

    Structure of amorphous chalcogenide semiconductor glassy As-S-Se films, obtained by high-frequency (HF) ion-plasma sputtering has been investigated. It was shown that the length of the atomic structure medium order and local structure were different from the films obtained by thermal vacuum evaporation. Temperature dependence of dark conductivity, as well as the dependence of the spectral transmittance has been studied. Conductivity value was determined at room temperature. Energy activation conductivity and films optical band gap have been calculated. Temperature and field dependence of the drift mobility of charge carriers in the HF As-S-Se films have been shown. Bipolarity of charge carriers drift mobility has been confirmed. Absence of deep traps for electrons in the As{sub 40}Se{sub 30}S{sub 30} spectrum of localized states for films obtained by HF plasma ion sputtering was determined. Bipolar drift of charge carriers was found in amorphous As{sub 40}Se{sub 30}S{sub 30} films obtained by ion-plasma sputtering of high-frequency, unlike the films of these materials obtained by thermal evaporation.

  4. Quantum Semiconductor Modeling Ansgar Jungel

    E-Print Network [OSTI]

    Jüngel, Ansgar

    Quantum Semiconductor Modeling Ansgar J¨ungel Vienna University of Technology, Austria www.jungel.at.vu Ansgar J¨ungel (TU Wien) Quantum Semiconductor Modeling www.jungel.at.vu 1 / 154 #12;Contents 1 Introduction 2 Semiconductor modeling 3 Microscopic quantum models Density matrices Schr¨odinger models Wigner

  5. Novel room temperature ferromagnetic semiconductors

    SciTech Connect (OSTI)

    Gupta, Amita

    2004-11-01T23:59:59.000Z

    Today's information world, bits of data are processed by semiconductor chips, and stored in the magnetic disk drives. But tomorrow's information technology may see magnetism (spin) and semiconductivity (charge) combined in one 'spintronic' device that exploits both charge and 'spin' to carry data (the best of two worlds). Spintronic devices such as spin valve transistors, spin light emitting diodes, non-volatile memory, logic devices, optical isolators and ultra-fast optical switches are some of the areas of interest for introducing the ferromagnetic properties at room temperature in a semiconductor to make it multifunctional. The potential advantages of such spintronic devices will be higher speed, greater efficiency, and better stability at a reduced power consumption. This Thesis contains two main topics: In-depth understanding of magnetism in Mn doped ZnO, and our search and identification of at least six new above room temperature ferromagnetic semiconductors. Both complex doped ZnO based new materials, as well as a number of nonoxides like phosphides, and sulfides suitably doped with Mn or Cu are shown to give rise to ferromagnetism above room temperature. Some of the highlights of this work are discovery of room temperature ferromagnetism in: (1) ZnO:Mn (paper in Nature Materials, Oct issue, 2003); (2) ZnO doped with Cu (containing no magnetic elements in it); (3) GaP doped with Cu (again containing no magnetic elements in it); (4) Enhancement of Magnetization by Cu co-doping in ZnO:Mn; (5) CdS doped with Mn, and a few others not reported in this thesis. We discuss in detail the first observation of ferromagnetism above room temperature in the form of powder, bulk pellets, in 2-3 mu-m thick transparent pulsed laser deposited films of the Mn (<4 at. percent) doped ZnO. High-resolution transmission electron microscopy (HRTEM) and electron energy loss spectroscopy (EELS) spectra recorded from 2 to 200nm areas showed homogeneous distribution of Mn substituting for Zn a 2+ state in the ZnO lattice. Ferromagnetic Resonance (FMR) technique is used to confirm the existence of ferromagnetic ordering at temperatures as high as 425K. The ab initio calculations were found to be consistent with the observation of ferromagnetism arising from fully polarized Mn 2+ state. The key to observed room temperature ferromagnetism in this system is the low temperature processing, which prevents formation of clusters, secondary phases and the host ZnO from becoming n-type. The electronic structure of the same Mn doped ZnO thin films studied using XAS, XES and RIXS, revealed a strong hybridization between Mn 3d and O 2p states, which is an important characteristic of a Dilute magnetic Semiconductor (DMS). It is shown that the various processing conditions like sintering temperature, dopant concentration and the properties of precursors used for making of DMS have a great influence on the final properties. Use of various experimental techniques to verify the physical properties, and to understand the mechanism involved to give rise to ferromagnetism is presented. Methods to improve the magnetic moment in Mn doped ZnO are also described. New promising DMS materials (such as Cu doped ZnO are explored). The demonstrated new capability to fabricate powder, pellets, and thin films of room temperature ferromagnetic semiconductors thus makes possible the realization of a wide range of complex elements for a variety of new multifunctional phenomena related to Spintronic devices as well as magneto-optic components.

  6. Kansas Advanced Semiconductor Project

    SciTech Connect (OSTI)

    Baringer, P.; Bean, A.; Bolton, T.; Horton-Smith, G.; Maravin, Y.; Ratra, B.; Stanton, N.; von Toerne, E.; Wilson, G.

    2007-09-21T23:59:59.000Z

    KASP (Kansas Advanced Semiconductor Project) completed the new Layer 0 upgrade for D0, assumed key electronics projects for the US CMS project, finished important new physics measurements with the D0 experiment at Fermilab, made substantial contributions to detector studies for the proposed e+e- international linear collider (ILC), and advanced key initiatives in non-accelerator-based neutrino physics.

  7. 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 ...

  8. 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 ...

  9. 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...

  10. 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.

  11. 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.

  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:Energy: Grid Integration Redefining What'sis Taking Over Our InstagramStructure of All-Polymer. . ~0sFailureSubscribe Mark

  13. 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

  14. 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

  15. 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

  16. 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

  17. 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

  18. Synthesis and Characterization of Mesoporous Semiconductors and Their Energy Applications

    E-Print Network [OSTI]

    Kang, Chris Byung-hwa

    2013-01-01T23:59:59.000Z

    Biomaterials, Ceramics, and Semiconductors. ” Science, 277,I. “Nanostructured Semiconductors Templated by Cholesteryl-Nanostructured Semiconductor. ” J. Am. Chem. Soc. , 127,

  19. A Novel Class of High-TC Ferromagnetic Semiconductors

    E-Print Network [OSTI]

    Shlyk, L. V.

    2008-01-01T23:59:59.000Z

    Diluted magnetic semiconductor or clustering effect? ”,ferromagnetism in semiconductors”, J. Appl. Phys. , inMaking nonmagnetic semiconductors ferromagnetic”, Science,

  20. Magnetization dynamics and spin diffusion in semiconductors and metals

    E-Print Network [OSTI]

    Cywi?ski, ?ukasz

    2007-01-01T23:59:59.000Z

    to (III,Mn)V ferromagnetic semiconductors . . . . . . . . .semiconductors . . . . . . . . . . . . . . . . . .Spin di?usion in semiconductors and metals: a general

  1. Effect of annealing on the kinetic properties and band parameters of Hg{sub 1?x?y}Cd{sub x}Eu{sub y}Se semiconductor crystals

    SciTech Connect (OSTI)

    Kovalyuk, T. T., E-mail: tarik-1006@mail.ru; Maistruk, E. V.; Maryanchuk, P. D. [Chernivtsy National University (Ukraine)

    2014-12-15T23:59:59.000Z

    The results of studies of the kinetic properties of Hg{sub 1?x?y}Cd{sub x}Eu{sub y}Se semiconductor crystals in the ranges of temperatures T = 77–300 K and magnetic fields H = 0.5–5 kOe before and after heat treatment of the samples in Se vapors are reported. It is established that annealing of the samples in Se vapors induces a decrease in the electron concentration. From the concentration dependence of the electron effective mass at the Fermi level, the band gap, the matrix element of interband interaction, and the electron effective mass at the bottom of the conduction band are determined.

  2. 2012 DEFECTS IN SEMICONDUCTORS GORDON RESEARCH CONFERENCE, AUGUST 12-17, 2012

    SciTech Connect (OSTI)

    GLASER, EVAN

    2012-08-17T23:59:59.000Z

    The meeting shall strive to develop and further the fundamental understanding of defects and their roles in the structural, electronic, optical, and magnetic properties of bulk, thin film, and nanoscale semiconductors and device structures. Point and extended defects will be addressed in a broad range of electronic materials of particular current interest, including wide bandgap semiconductors, metal-oxides, carbon-based semiconductors (e.g., diamond, graphene, etc.), organic semiconductors, photovoltaic/solar cell materials, and others of similar interest. This interest includes novel defect detection/imaging techniques and advanced defect computational methods.

  3. Radiation Detection Laboratory The Detection for Nuclear Nonproliferation Lab is used to explore novel techniques for radiation

    E-Print Network [OSTI]

    Kamat, Vineet R.

    NERS Radiation Detection Laboratory The Detection for Nuclear Nonproliferation Lab is used to explore novel techniques for radiation detection and characterization for nuclear nonproliferation); Development of TlBr wide band-gap semiconductor detectors (Radiation Monitoring Devices and DNDO of DHS

  4. Infrared spectroscopy of ZnO nanoparticles containing CO2 impurities W. M. Hlaing Oo and M. D. McCluskeya

    E-Print Network [OSTI]

    McCluskey, Matthew

    Institute of Physics. DOI: 10.1063/1.1866511 Zinc oxide ZnO is a wide-band gap semiconductor that is desirable for many applications, such as piezoelectric transducers, varistors, gas sensors, and transparent synthesized by a variety of wet-chemistry methods. The use of precursor materials such as zinc acetate, zinc

  5. Diameter-Controlled Vapor-Solid Epitaxial Growth and Properties of Aligned ZnO Nanowire Arrays

    E-Print Network [OSTI]

    Qin, Lu-Chang

    . Introduction Wurtzitic zinc oxide is a direct, wide band gap semiconductor that has attracted tremendous (ultraviolet or green/blue) electro-optical devices, chemical sensors, and varistors.1-5 In recent years oxide, so their commercial potential has been limited. Here we report a facile, template-free method

  6. Open Archive TOULOUSE Archive Ouverte (OATAO) OATAO is an open access repository that collects the work of Toulouse researchers and

    E-Print Network [OSTI]

    Mailhes, Corinne

    as for transparent electronics; thin-film solar cells2 and flat panel displays3,4 are typical applica- tions of samples deposited at different pressures, which provides an insight into the defect surface properties. ZnO is an n-type semiconductor with a wide direct band gap energy of 3.37 eV at room

  7. Ga NMR spectra and relaxation in wurtzite GaN M. Corti and A. Gabetta

    E-Print Network [OSTI]

    Svane, Axel Torstein

    69,71 Ga NMR spectra and relaxation in wurtzite GaN M. Corti and A. Gabetta Department of Physics properties of wurtzite GaN are studied by Ga nuclear magnetic resonance NMR in a GaN bulk crystal containing GaN is a wide band-gap semiconductor which crystallizes in the hexagonal wurtzite structure

  8. Anodic Aluminum Oxide Templated Channel Electrodes via Atomic Layer A. B. F. Martinsona,b

    E-Print Network [OSTI]

    60439, USA Dye-sensitized solar cells (DSSCs) utilize high surface area metal oxide sintered particle aluminum oxide membranes via atomic layer deposition. Introduction Dye sensitized solar cells (DSSCs) These photoelectrochemical cells use molecular dyes to sensitize high area, wide band gap semiconductor oxide photoanodes

  9. A Porous Multilayer Dye-Based Photoelectrochemical Cell That Unexpectedly Runs Kathryn E. Splan, Aaron M. Massari, and Joseph T. Hupp*

    E-Print Network [OSTI]

    -area dye-sensitized solar cells has advanced significantly over the past 12 years, the cells themselves with conventional dye-senstized solar cells (DSSCs). In constrast to DSSCs, which work by electron injection from photochemical approaches to solar energy conversion is dye sensitization of wide band gap semiconductors.1

  10. Zone-boundary phonons in hexagonal and cubic GaN H. Siegle, G. Kaczmarczyk, L. Filippidis, A. P. Litvinchuk, A. Hoffmann, and C. Thomsen

    E-Print Network [OSTI]

    Nabben, Reinhard

    Zone-boundary phonons in hexagonal and cubic GaN H. Siegle, G. Kaczmarczyk, L. Filippidis, A. P results of second-order Raman-scattering experiments on hexagonal and cubic GaN covering the acoustic- boundary phonons in hexagonal GaN. S0163-1829 97 01812-2 I. INTRODUCTION The wide-band-gap semiconductor GaN

  11. Semiconductor radiation detector

    DOE Patents [OSTI]

    Patt, Bradley E. (Sherman Oaks, CA); Iwanczyk, Jan S. (Los Angeles, CA); Tull, Carolyn R. (Orinda, CA); Vilkelis, Gintas (Westlake Village, CA)

    2002-01-01T23:59:59.000Z

    A semiconductor radiation detector is provided to detect x-ray and light photons. The entrance electrode is segmented by using variable doping concentrations. Further, the entrance electrode is physically segmented by inserting n+ regions between p+ regions. The p+ regions and the n+ regions are individually biased. The detector elements can be used in an array, and the p+ regions and the n+ regions can be biased by applying potential at a single point. The back side of the semiconductor radiation detector has an n+ anode for collecting created charges and a number of p+ cathodes. Biased n+ inserts can be placed between the p+ cathodes, and an internal resistor divider can be used to bias the n+ inserts as well as the p+ cathodes. A polysilicon spiral guard can be implemented surrounding the active area of the entrance electrode or surrounding an array of entrance electrodes.

  12. WWW.MOTOROLA.COM/SEMICONDUCTORS Microcontrollers

    E-Print Network [OSTI]

    Song, Joe

    WWW.MOTOROLA.COM/SEMICONDUCTORS M68HC11 Microcontrollers M68HC11RM/D Rev. 6, 4/2002 M68HC11 Reference Manual FreescaleSemiconductor,I Freescale Semiconductor, Inc. For More Information On This Product, Go to: www.freescale.com nc... #12;FreescaleSemiconductor,I Freescale Semiconductor, Inc. For More

  13. Coherence and focusing properties of unstable resonator semiconductor lasers

    SciTech Connect (OSTI)

    Mittelstein, M.; Salzman, J.; Venkatesan, T.; Lang, R.; Yariv, A.

    1985-05-15T23:59:59.000Z

    The emission characteristics of unstable resonator semiconductor lasers were measured. The output of an 80-..mu..m-wide laser consists of a diverging beam with a virtual source 5 ..mu..m wide located 50 ..mu..m behind the laser facet. A high degree of spatial coherence of the laser output was measured, indicating single lateral mode operation for currents I< or approx. =3 I/sub th/.

  14. Semiconductor bridge, SCB, ignition of energetic materials

    SciTech Connect (OSTI)

    Bickes, R.W.; Grubelich, M.D.; Harris, S.M.; Merson, J.A.; Tarbell, W.W.

    1997-04-01T23:59:59.000Z

    Sandia National Laboratories` semiconductor bridge, SCB, is now being used for the ignition or initiation of a wide variety of exeoergic materials. Applications of this new technology arose because of a need at the system level to provide light weight, small volume and low energy explosive assemblies. Conventional bridgewire devices could not meet the stringent size, weight and energy requirements of our customers. We present an overview of SCB technology and the ignition characteristics for a number of energetic materials including primary and secondary explosives, pyrotechnics, thermites and intermetallics. We provide examples of systems designed to meet the modern requirements that sophisticated systems must satisfy in today`s market environments.

  15. Semiconductor lasers with uniform longitudinal intensity distribution

    SciTech Connect (OSTI)

    Schrans, T.; Yariv, A. (Department of Applied Physics 128-95, California Institute of Technology, Pasadena, California 91125 (USA))

    1990-04-16T23:59:59.000Z

    Power-dependent nonuniform longitudinal intensity distribution leading to spectral and spatial instabilities is a major problem in semiconductor lasers. It is shown theoretically that a proper choice of the longitudinal distribution of the gain as well as that of the magnitude of the grating coupling coefficient will lead to a uniform intensity distribution in distributed feedback lasers. We also show that the widely used phase, rather than magnitude, control of the coupling coefficient cannot lead to a uniform intensity distribution when the facet reflectivities are zero.

  16. Method of passivating semiconductor surfaces

    DOE Patents [OSTI]

    Wanlass, Mark W. (Golden, CO)

    1990-01-01T23:59:59.000Z

    A method of passivating Group III-V or II-VI semiconductor compound surfaces. The method includes selecting a passivating material having a lattice constant substantially mismatched to the lattice constant of the semiconductor compound. The passivating material is then grown as an ultrathin layer of passivating material on the surface of the Group III-V or II-VI semiconductor compound. The passivating material is grown to a thickness sufficient to maintain a coherent interface between the ultrathin passivating material and the semiconductor compound. In addition, a device formed from such method is also disclosed.

  17. Sandia National Laboratories: compound semiconductor

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

    compound semiconductor Sandia and EMCORE: Solar Photovoltaics, Fiber Optics, MODE, and Energy Efficiency On March 29, 2013, in Concentrating Solar Power, Energy, Partnership,...

  18. Method of passivating semiconductor surfaces

    DOE Patents [OSTI]

    Wanlass, M.W.

    1990-06-19T23:59:59.000Z

    A method is described for passivating Group III-V or II-VI semiconductor compound surfaces. The method includes selecting a passivating material having a lattice constant substantially mismatched to the lattice constant of the semiconductor compound. The passivating material is then grown as an ultrathin layer of passivating material on the surface of the Group III-V or II-VI semiconductor compound. The passivating material is grown to a thickness sufficient to maintain a coherent interface between the ultrathin passivating material and the semiconductor compound. In addition, a device formed from such method is also disclosed.

  19. Noise and synamics in semiconductor lasers

    E-Print Network [OSTI]

    Rana, Farhan, 1971-

    2003-01-01T23:59:59.000Z

    In this thesis, theoretical and experimental work on the noise and dynamics in continuous wave and mode-locked semiconductor lasers is presented. The main focus is on semiconductor cascade lasers and semiconductor mode-locked ...

  20. Semiconductors: From Manipulated to Managed Trade

    E-Print Network [OSTI]

    Tyson, Laura D'Andrea; Yoffie, David B.

    1991-01-01T23:59:59.000Z

    o f the Japanese semiconductor industry is a sucecsslul aridcommodnv product Ol the semiconductor industry. They are afor maJtini: semiconductors: »nc

  1. Electron vortices in semiconductors devicesa... Kamran Mohsenib

    E-Print Network [OSTI]

    Electron vortices in semiconductors devicesa... Kamran Mohsenib Aerospace Engineering Sciencies; published online 3 October 2005 The hydrodynamic model of electron transport in semiconductors is analyzed vorticity effects. Furthermore, conditions for observation of electron vortices in semiconductor devices

  2. Climate VISION: Private Sector Initiatives: Semiconductors

    Office of Scientific and Technical Information (OSTI)

    Agreements The U.S. semiconductor industry, represented by the members of the Environmental Protection Agency's PFC ReductionClimate Partnership for the Semiconductor...

  3. Climate VISION: Private Sector Initiatives: Semiconductors: Resources...

    Office of Scientific and Technical Information (OSTI)

    over 100 companies that account for more than 83% of U.S.-based semiconductor production. The SIA provides a forum for domestic semiconductor companies to work collectively...

  4. Characterization of Amorphous Zinc Tin Oxide Semiconductors....

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

    Amorphous Zinc Tin Oxide Semiconductors. Characterization of Amorphous Zinc Tin Oxide Semiconductors. Abstract: Amorphous zinc tin oxide (ZTO) was investigated to determine the...

  5. Layered semiconductor neutron detectors

    DOE Patents [OSTI]

    Mao, Samuel S; Perry, Dale L

    2013-12-10T23:59:59.000Z

    Room temperature operating solid state hand held neutron detectors integrate one or more relatively thin layers of a high neutron interaction cross-section element or materials with semiconductor detectors. The high neutron interaction cross-section element (e.g., Gd, B or Li) or materials comprising at least one high neutron interaction cross-section element can be in the form of unstructured layers or micro- or nano-structured arrays. Such architecture provides high efficiency neutron detector devices by capturing substantially more carriers produced from high energy .alpha.-particles or .gamma.-photons generated by neutron interaction.

  6. Variable temperature semiconductor film deposition

    DOE Patents [OSTI]

    Li, Xiaonan (Golden, CO); Sheldon, Peter (Lakewood, CO)

    1998-01-01T23:59:59.000Z

    A method of depositing a semiconductor material on a substrate. The method sequentially comprises (a) providing the semiconductor material in a depositable state such as a vapor for deposition on the substrate; (b) depositing the semiconductor material on the substrate while heating the substrate to a first temperature sufficient to cause the semiconductor material to form a first film layer having a first grain size; (c) continually depositing the semiconductor material on the substrate while cooling the substrate to a second temperature sufficient to cause the semiconductor material to form a second film layer deposited on the first film layer and having a second grain size smaller than the first grain size; and (d) raising the substrate temperature, while either continuing or not continuing to deposit semiconductor material to form a third film layer, to thereby anneal the film layers into a single layer having favorable efficiency characteristics in photovoltaic applications. A preferred semiconductor material is cadmium telluride deposited on a glass/tin oxide substrate already having thereon a film layer of cadmium sulfide.

  7. Process for producing chalcogenide semiconductors

    DOE Patents [OSTI]

    Noufi, R.; Chen, Y.W.

    1985-04-30T23:59:59.000Z

    A process for producing chalcogenide semiconductor material is disclosed. The process includes forming a base metal layer and then contacting this layer with a solution having a low pH and containing ions from at least one chalcogen to chalcogenize the layer and form the chalcogenide semiconductor material.

  8. Variable temperature semiconductor film deposition

    DOE Patents [OSTI]

    Li, X.; Sheldon, P.

    1998-01-27T23:59:59.000Z

    A method of depositing a semiconductor material on a substrate is disclosed. The method sequentially comprises (a) providing the semiconductor material in a depositable state such as a vapor for deposition on the substrate; (b) depositing the semiconductor material on the substrate while heating the substrate to a first temperature sufficient to cause the semiconductor material to form a first film layer having a first grain size; (c) continually depositing the semiconductor material on the substrate while cooling the substrate to a second temperature sufficient to cause the semiconductor material to form a second film layer deposited on the first film layer and having a second grain size smaller than the first grain size; and (d) raising the substrate temperature, while either continuing or not continuing to deposit semiconductor material to form a third film layer, to thereby anneal the film layers into a single layer having favorable efficiency characteristics in photovoltaic applications. A preferred semiconductor material is cadmium telluride deposited on a glass/tin oxide substrate already having thereon a film layer of cadmium sulfide.

  9. Process for producing chalcogenide semiconductors

    DOE Patents [OSTI]

    Noufi, Rommel (Westminster, CO); Chen, Yih-Wen (Omaha, NE)

    1987-01-01T23:59:59.000Z

    A process for producing chalcogenide semiconductor material is disclosed. The process includes forming a base metal layer and then contacting this layer with a solution having a low pH and containing ions from at least one chalcogen to chalcogenize the layer and form the chalcogenide semiconductor material.

  10. Physics with isotopically controlled semiconductors

    SciTech Connect (OSTI)

    Haller, E. E., E-mail: eehaller@lbl.gov [University of California at Berkeley, Department of Materials Science and Engineering (United States)

    2010-07-15T23:59:59.000Z

    This paper is based on a tutorial presentation at the International Conference on Defects in Semiconductors (ICDS-25) held in Saint Petersburg, Russia in July 2009. The tutorial focused on a review of recent research involving isotopically controlled semiconductors. Studies with isotopically enriched semiconductor structures experienced a dramatic expansion at the end of the Cold War when significant quantities of enriched isotopes of elements forming semiconductors became available for worldwide collaborations. Isotopes of an element differ in nuclear mass, may have different nuclear spins and undergo different nuclear reactions. Among the latter, the capture of thermal neutrons which can lead to neutron transmutation doping, is the most prominent effect for semiconductors. Experimental and theoretical research exploiting the differences in all the properties has been conducted and will be illustrated with selected examples.

  11. 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.

  12. Semiconductor device PN junction fabrication using optical processing of amorphous semiconductor material

    DOE Patents [OSTI]

    Sopori, Bhushan; Rangappan, Anikara

    2014-11-25T23:59:59.000Z

    Systems and methods for semiconductor device PN junction fabrication are provided. In one embodiment, a method for fabricating an electrical device having a P-N junction comprises: depositing a layer of amorphous semiconductor material onto a crystalline semiconductor base, wherein the crystalline semiconductor base comprises a crystalline phase of a same semiconductor as the amorphous layer; and growing the layer of amorphous semiconductor material into a layer of crystalline semiconductor material that is epitaxially matched to the lattice structure of the crystalline semiconductor base by applying an optical energy that penetrates at least the amorphous semiconductor material.

  13. Semiconductor Bridge Cable Test

    SciTech Connect (OSTI)

    KING, TONY L.

    2002-01-01T23:59:59.000Z

    The semiconductor bridge (SCB) is an electroexplosive device used to initiate detonators. A C cable is commonly used to connect the SCB to a firing set. A series of tests were performed to identify smaller, lighter cables for firing single and multiple SCBs. This report provides a description of these tests and their results. It was demonstrated that lower threshold voltages and faster firing times can be achieved by increasing the wire size, which reduces ohmic losses. The RF 100 appears to be a reasonable substitute for C cable when firing single SCBs. This would reduce the cable volume by 68% and the weight by 67% while increasing the threshold voltage by only 22%. In general, RG 58 outperforms twisted pair when firing multiple SCBs in parallel. The RG 58's superior performance is attributed to its larger conductor size.

  14. Mathematical Modeling of Semiconductor Devices

    E-Print Network [OSTI]

    Jüngel, Ansgar

    fibers. · Optoelectronic emitters convert an electronic signal into light. Examples are light-emitting diodes (LED) used in displays and indication lambs and semiconductor lasers used in compact disk systems

  15. Modeling the semiconductor industry dynamics

    E-Print Network [OSTI]

    Wu, Kailiang

    2008-01-01T23:59:59.000Z

    The semiconductor industry is an exciting and challenging industry. Strong demand at the application end, plus the high capital intensity and rapid technological innovation in manufacturing, makes it difficult to manage ...

  16. Controlled buckling structures in semiconductor interconnects and nanomembranes for stretchable electronics

    DOE Patents [OSTI]

    Rogers, John A. (Champaign, IL); Meitl, Matthew (Raleigh, NC); Sun, Yugang (Naperville, IL); Ko, Heung Cho (Urbana, IL); Carlson, Andrew (Urbana, IL); Choi, Won Mook (Champaign, IL); Stoykovich, Mark (Dover, NH); Jiang, Hanqing (Urbana, IL); Huang, Yonggang (Glencoe, IL); Nuzzo, Ralph G. (Champaign, IL); Lee, Keon Jae (Tokyo, JP); Zhu, Zhengtao (Rapid City, SD); Menard, Etienne (Durham, NC); Khang, Dahl-Young (Seoul, KR); Kan, Seong Jun (Daejeon, KR); Ahn, Jong Hyun (Suwon, KR); Kim, Hoon-sik (Champaign, IL)

    2012-07-10T23:59:59.000Z

    In an aspect, the present invention provides stretchable, and optionally printable, components such as semiconductors and electronic circuits capable of providing good performance when stretched, compressed, flexed or otherwise deformed, and related methods of making or tuning such stretchable components. Stretchable semiconductors and electronic circuits preferred for some applications are flexible, in addition to being stretchable, and thus are capable of significant elongation, flexing, bending or other deformation along one or more axes. Further, stretchable semiconductors and electronic circuits of the present invention are adapted to a wide range of device configurations to provide fully flexible electronic and optoelectronic devices.

  17. Controlled buckling structures in semiconductor interconnects and nanomembranes for stretchable electronics

    DOE Patents [OSTI]

    Rogers, John A; Meitl, Matthew; Sun, Yugang; Ko, Heung Cho; Carlson, Andrew; Choi, Won Mook; Stoykovich, Mark; Jiang, Hanqing; Huang, Yonggang; Nuzzo, Ralph G; Zhu, Zhengtao; Menard, Etienne; Khang, Dahl-Young

    2014-05-20T23:59:59.000Z

    In an aspect, the present invention provides stretchable, and optionally printable, components such as semiconductors and electronic circuits capable of providing good performance when stretched, compressed, flexed or otherwise deformed, and related methods of making or tuning such stretchable components. Stretchable semiconductors and electronic circuits preferred for some applications are flexible, in addition to being stretchable, and thus are capable of significant elongation, flexing, bending or other deformation along one or more axes. Further, stretchable semiconductors and electronic circuits of the present invention are adapted to a wide range of device configurations to provide fully flexible electronic and optoelectronic devices.

  18. Universal alignment of hydrogen levels in semiconductors and insulators

    E-Print Network [OSTI]

    Van de Walle, C G

    2006-01-01T23:59:59.000Z

    including nitride semiconductors and transparent oxides.and C. G. Van de Walle, in Hydrogen in SemiconductorsII, Semiconductors and Semimetals Vol. 61, edited by N. H.

  19. Identifying semiconductors by d.c. ionization conductivity

    E-Print Network [OSTI]

    2006-01-01T23:59:59.000Z

    expected from high-Z semiconductor detectors? ,” IEEE Transand binary compound semiconductors and insulators,” J PhysIdentifying Semiconductors by D.C. Ionization Conductivity

  20. Nitride semiconductor Surface and interface characterization and device design

    E-Print Network [OSTI]

    Zhang, Hongtao

    2006-01-01T23:59:59.000Z

    Lett. 80 , D. Schroder, Semiconductor Material and Devicein III-V Nitride Semiconductors: Applications and Devices ,SAN DIEGO Nitride Semiconductor Surface and Interface

  1. Semiconductor Quantum Rods as Single Molecule Fluorescent Biological Labels

    E-Print Network [OSTI]

    2006-01-01T23:59:59.000Z

    Alivisatos, A.P. Semiconductor nanocrystas for biologicalemission from colloidal semiconductor quantum rods. ScienceLight amplification in semiconductor nanocrystals: Quantum

  2. Enhanced Semiconductor Nanocrystal Conductance via Solution Grown Contacts

    E-Print Network [OSTI]

    Sheldon, Matthew T.

    2010-01-01T23:59:59.000Z

    G. ; Avouris, P. , Metal-semiconductor nanocontacts: SiliconIndividual Colloidal Semiconductor Nanorods. Nano Lett 2008,Physical Chemistry of Semiconductor Nanocrystals. J. Phys.

  3. Isovalent Anion Substitution in Ga-Mn-pnictide Ferromagnetic Semiconductors

    E-Print Network [OSTI]

    Stone, Peter

    2010-01-01T23:59:59.000Z

    63. O. Madelung, Semiconductors - Basic Data, 2nd Ed. (in Laser Annealing of Semiconductors, edited by J. M. PoateProperties of Semiconductors ("Atom" Publ. House, Moscow,

  4. Diffraction coupled phase-locked semiconductor laser array

    SciTech Connect (OSTI)

    Katz, J.; Margalit, S.; Yariv, A.

    1983-04-01T23:59:59.000Z

    A new monolithic, diffraction coupled phase-locked semiconductor laser array has been fabricated. Stable narrow far-field patterns (approx.3/sup 0/) and peak power levels of 1 W have been obtained for 100-..mu..m-wide devices with threshold currents as low as 250 mA. Such devices may be useful in applications where high power levels and stable radiation patterns are needed.

  5. Impurity gettering in semiconductors

    DOE Patents [OSTI]

    Sopori, B.L.

    1995-06-20T23:59:59.000Z

    A process for impurity gettering in a semiconductor substrate or device such as a silicon substrate or device is disclosed. The process comprises hydrogenating the substrate or device at the back side thereof with sufficient intensity and for a time period sufficient to produce a damaged back side. Thereafter, the substrate or device is illuminated with electromagnetic radiation at an intensity and for a time period sufficient to cause the impurities to diffuse to the back side and alloy with a metal there present to form a contact and capture the impurities. The impurity gettering process also can function to simultaneously passivate defects within the substrate or device, with the defects likewise diffusing to the back side for simultaneous passivation. Simultaneously, substantially all hydrogen-induced damage on the back side of the substrate or device is likewise annihilated. Also taught is an alternate process comprising thermal treatment after hydrogenation of the substrate or device at a temperature of from about 500 C to about 700 C for a time period sufficient to cause the impurities to diffuse to the damaged back side thereof for subsequent capture by an alloying metal. 1 fig.

  6. Impurity gettering in semiconductors

    DOE Patents [OSTI]

    Sopori, Bhushan L. (Denver, CO)

    1995-01-01T23:59:59.000Z

    A process for impurity gettering in a semiconductor substrate or device such as a silicon substrate or device. The process comprises hydrogenating the substrate or device at the back side thereof with sufficient intensity and for a time period sufficient to produce a damaged back side. Thereafter, the substrate or device is illuminated with electromagnetic radiation at an intensity and for a time period sufficient to cause the impurities to diffuse to the back side and alloy with a metal there present to form a contact and capture the impurities. The impurity gettering process also can function to simultaneously passivate defects within the substrate or device, with the defects likewise diffusing to the back side for simultaneous passivation. Simultaneously, substantially all hydrogen-induced damage on the back side of the substrate or device is likewise annihilated. Also taught is an alternate process comprising thermal treatment after hydrogenation of the substrate or device at a temperature of from about 500.degree. C. to about 700.degree. C. for a time period sufficient to cause the impurities to diffuse to the damaged back side thereof for subsequent capture by an alloying metal.

  7. Linear tailored gain broad area semiconductor lasers

    SciTech Connect (OSTI)

    Lindsey, C.P.; Mehuys, D.; Yariv, A.

    1987-06-01T23:59:59.000Z

    Tailored gain semiconductor lasers capable of high-power operation with single-lobed, nearly diffraction limited beamwidths only a few degrees wide have been demonstrated in proton implanted chirped arrays and ''halftone'' broad area lasers. The authors analyze lasers with a linear gain gradient, and obtain analytic approximations for their unsaturated optical eigenmodes. Unlike a uniform array, the fundamental mode of a linear tailored gain laser is the mode at threshold. Mode discrimination may be controlled by lasing the spatial gain gradient. All modes of asymmetric tailored gain waveguides have single-lobed far-field patterns offset from 0/sup 0/. Finally, they utilize tailored gain broad area lasers to make a measurement of the antiguiding parameter, and find b = 2.5 +- 0.5, in agreement with previous results.

  8. Theory of Organic Magnetoresistance in Disordered Organic Semiconductors

    E-Print Network [OSTI]

    Flatte, Michael E.

    Theory of Organic Magnetoresistance in Disordered Organic Semiconductors Nicholas J. Harmon semiconductors, disordered semiconductors, organic magnetoresistance, percolation theory, spin transport organic semiconductors. The theory proposed here maps the complex phenomena of spin-dependent hopping onto

  9. ECE 344--Semiconductor Devices & Materials ECE Department, UMass Amherst

    E-Print Network [OSTI]

    Massachusetts at Amherst, University of

    1 Syllabus ECE 344--Semiconductor Devices & Materials ECE Department, UMass Amherst Fall 2013 transport in semiconductors Explain the operating principles in semiconductor devices (diodes, capacitors Topics: Fundamentals of Semiconductors; Theory of Electrical Conduction; Device Operations (See "Class

  10. ECE 609 Semiconductor Devices Department of Electrical and Computer Engineering

    E-Print Network [OSTI]

    Massachusetts at Amherst, University of

    ECE 609 ­ Semiconductor Devices Department of Electrical and Computer Engineering University of semiconductor electronic devices in terms of material properties, interface and junction characteristics). ________________________________________________________________________ Preliminary Course Outline 1. Overview of Semiconductor Physics 1.1 Semiconductor Materials

  11. ECE 609 Semiconductor Devices Department of Electrical and Computer Engineering

    E-Print Network [OSTI]

    Massachusetts at Amherst, University of

    ECE 609 ­ Semiconductor Devices Department of Electrical and Computer Engineering University. ________________________________________________________________________ Preliminary Course Outline 1. Overview of Semiconductor Physics 1.1 Semiconductor Materials-V Characteristics, Nonideal Behavior) 2.2 Metal Semiconductor Junctions (Schottky Barriers, Ohmic Contacts) 2

  12. Sintered molybdenum for a metallized ceramic substrate packaging for the wide-

    E-Print Network [OSTI]

    Boyer, Edmond

    ; molybdenum; Spark Plasma Sintering I. INTRODUCTION Wide-bandgap semiconductors devices, such as silicon nitride (AlN) and molybdenum (Mo) is reported in this paper. This substrate is built using a spark plasmaSintered molybdenum for a metallized ceramic substrate packaging for the wide- bandgap devices

  13. Correlated exciton dynamics in semiconductor nanostructures

    E-Print Network [OSTI]

    Wen, Patrick, Ph. D. Massachusetts Institute of Technology

    2013-01-01T23:59:59.000Z

    The absorption and dissipation of energy in semiconductor nanostructures are often determined by excited electron dynamics. In semiconductors, one fundamentally important electronic state is an exciton, an excited electron ...

  14. Method of preparing nitrogen containing semiconductor material

    DOE Patents [OSTI]

    Barber, Greg D.; Kurtz, Sarah R.

    2004-09-07T23:59:59.000Z

    A method of combining group III elements with group V elements that incorporates at least nitrogen from a nitrogen halide for use in semiconductors and in particular semiconductors in photovoltaic cells.

  15. Disordered electronic and magnetic systems - transition metal (Mn) and rare earth (Gd) doped amorphous group IV semiconductors (C, Si, Ge)

    E-Print Network [OSTI]

    Zeng, Li

    2007-01-01T23:59:59.000Z

    1.1 Magnetic Semiconductors . . . . . . . . . . . . . . .Semiconductors . . . . . . . . . . . . . . . . . . . 1.3in Semiconductors . . . . . . . . . . . . . . . . . . 1.3.5

  16. Semiconductor electrode with improved photostability characteristics

    DOE Patents [OSTI]

    Frank, A.J.

    1985-02-19T23:59:59.000Z

    An electrode is described for use in photoelectrochemical cells having an electrolyte which includes an aqueous constituent. The electrode consists of a semiconductor and a hydrophobic film disposed between the semiconductor and the aqueous constituent. The hydrophobic film is adapted to permit charges to pass therethrough while substantially decreasing the activity of the aqueous constituent at the semiconductor surface thereby decreasing the photodegradation of the semiconductor electrode.

  17. Semiconductor nanocrystal-based phagokinetic tracking

    DOE Patents [OSTI]

    Alivisatos, A Paul; Larabell, Carolyn A; Parak, Wolfgang J; Le Gros, Mark; Boudreau, Rosanne

    2014-11-18T23:59:59.000Z

    Methods for determining metabolic properties of living cells through the uptake of semiconductor nanocrystals by cells. Generally the methods require a layer of neutral or hydrophilic semiconductor nanocrystals and a layer of cells seeded onto a culture surface and changes in the layer of semiconductor nanocrystals are detected. The observed changes made to the layer of semiconductor nanocrystals can be correlated to such metabolic properties as metastatic potential, cell motility or migration.

  18. Review: Semiconductor Quantum Light Sources

    E-Print Network [OSTI]

    Andrew J Shields

    2007-04-03T23:59:59.000Z

    Lasers and LEDs display a statistical distribution in the number of photons emitted in a given time interval. New applications exploiting the quantum properties of light require sources for which either individual photons, or pairs, are generated in a regulated stream. Here we review recent research on single-photon sources based on the emission of a single semiconductor quantum dot. In just a few years remarkable progress has been made in generating indistinguishable single-photons and entangled photon pairs using such structures. It suggests it may be possible to realise compact, robust, LED-like semiconductor devices for quantum light generation.

  19. Semiconductor films on flexible iridium substrates

    DOE Patents [OSTI]

    Goyal, Amit

    2005-03-29T23:59:59.000Z

    A laminate semiconductor article includes a flexible substrate, an optional biaxially textured oxide buffer system on the flexible substrate, a biaxially textured Ir-based buffer layer on the substrate or the buffer system, and an epitaxial layer of a semiconductor. Ir can serve as a substrate with an epitaxial layer of a semiconductor thereon.

  20. Multi-phonon-assisted absorption and emission in semiconductors and its potential for laser refrigeration

    E-Print Network [OSTI]

    Khurgin, Jacob B

    2014-01-01T23:59:59.000Z

    Laser cooling of semiconductors has been an elusive goal for many years, and while attempts to cool the narrow gap semiconductors such as GaAs are yet to succeed, recently, net cooling has been attained in a wider gap CdS. This raises the question of whether wider gap semiconductors with higher phonon energies and stronger electron-phonon coupling are better suitable for laser cooling. In this work we develop a straightforward theory of phonon-assisted absorption and photoluminescence of semiconductors that involves more than one phonon and use to examine wide gap materials, such as GaN and CdS and compare them with GaAs. The results indicate that while strong electron-phonon coupling in both GaN and CdS definitely improves the prospects of laser cooling, large phonon energy in GaN may be a limitation, which makes CdS a better prospect for laser cooling.

  1. Multi-phonon-assisted absorption and emission in semiconductors and its potential for laser refrigeration

    SciTech Connect (OSTI)

    Khurgin, Jacob B., E-mail: jakek@jhu.edu [Johns Hopkins University, Baltimore, Maryland 21208 (United States)

    2014-06-02T23:59:59.000Z

    Laser cooling of semiconductors has been an elusive goal for many years, and while attempts to cool the narrow gap semiconductors such as GaAs are yet to succeed, recently, net cooling has been attained in a wider gap CdS. This raises the question of whether wider gap semiconductors with higher phonon energies and stronger electron-phonon coupling are better suitable for laser cooling. In this work, we develop a straightforward theory of phonon-assisted absorption and photoluminescence of semiconductors that involves more than one phonon and use to examine wide gap materials, such as GaN and CdS and compare them with GaAs. The results indicate that while strong electron-phonon coupling in both GaN and CdS definitely improves the prospects of laser cooling, large phonon energy in GaN may be a limitation, which makes CdS a better prospect for laser cooling.

  2. Mechanical scriber for semiconductor devices

    DOE Patents [OSTI]

    Lin, P.T.

    1985-03-05T23:59:59.000Z

    A mechanical scriber using a scribing tip, such as a diamond, provides controlled scriber forces with a spring-loaded compound lever arrangement. The scribing force and range of scribing depth are adjusted by a pair of adjustable micrometer heads. A semiconductor device, such as a multilayer solar cell, can be formed into scribed strips at each layer. 5 figs.

  3. Mechanical scriber for semiconductor devices

    DOE Patents [OSTI]

    Lin, Peter T. (East Brunswick, NJ)

    1985-01-01T23:59:59.000Z

    A mechanical scriber using a scribing tip, such as a diamond, provides controlled scriber forces with a spring-loaded compound lever arrangement. The scribing force and range of scribing depth are adjusted by a pair of adjustable micrometer heads. A semiconductor device, such as a multilayer solar cell, can be formed into scribed strips at each layer.

  4. Wide Blue Sky

    E-Print Network [OSTI]

    Collins, Caroline Imani

    2011-01-01T23:59:59.000Z

    dressed neatly in a dark blue dress, its high neck trimmedIt was covered in a light blue fabric embellished with softOF CALIFORNIA RIVERSIDE Wide Blue Sky A Thesis submitted in

  5. Controlled growth of semiconductor crystals

    DOE Patents [OSTI]

    Bourret-Courchesne, E.D.

    1992-07-21T23:59:59.000Z

    A method is disclosed for growth of III-V, II-VI and related semiconductor single crystals that suppresses random nucleation and sticking of the semiconductor melt at the crucible walls. Small pieces of an oxide of boron B[sub x]O[sub y] are dispersed throughout the comminuted solid semiconductor charge in the crucible, with the oxide of boron preferably having water content of at least 600 ppm. The crucible temperature is first raised to a temperature greater than the melt temperature T[sub m1] of the oxide of boron (T[sub m1]=723 K for boron oxide B[sub 2]O[sub 3]), and the oxide of boron is allowed to melt and form a reasonably uniform liquid layer between the crucible walls and bottom surfaces and the still-solid semiconductor charge. The temperature is then raised to approximately the melt temperature T[sub m2] of the semiconductor charge material, and crystal growth proceeds by a liquid encapsulated, vertical gradient freeze process. About half of the crystals grown have a dislocation density of less than 1000/cm[sup 2]. If the oxide of boron has water content less than 600 ppm, the crucible material should include boron nitride, a layer of the inner surface of the crucible should be oxidized before the oxide of boron in the crucible charge is melted, and the sum of thicknesses of the solid boron oxide layer and liquid boron oxide layer should be at least 50 [mu]m. 7 figs.

  6. Controlled growth of semiconductor crystals

    DOE Patents [OSTI]

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

    1992-01-01T23:59:59.000Z

    A method for growth of III-V, II-VI and related semiconductor single crystals that suppresses random nucleation and sticking of the semiconductor melt at the crucible walls. Small pieces of an oxide of boron B.sub.x O.sub.y are dispersed throughout the comminuted solid semiconductor charge in the crucible, with the oxide of boron preferably having water content of at least 600 ppm. The crucible temperature is first raised to a temperature greater than the melt temperature T.sub.m1 of the oxide of boron (T.sub.m1 =723.degree. K. for boron oxide B.sub.2 O.sub.3), and the oxide of boron is allowed to melt and form a reasonably uniform liquid layer between the crucible walls and bottom surfaces and the still-solid semiconductor charge. The temperature is then raised to approximately the melt temperature T.sub.m2 of the semiconductor charge material, and crystal growth proceeds by a liquid encapsulated, vertical gradient freeze process. About half of the crystals grown have a dislocation density of less than 1000/cm.sup.2. If the oxide of boron has water content less than 600 ppm, the crucible material should include boron nitride, a layer of the inner surface of the crucible should be oxidized before the oxide of boron in the crucible charge is melted, and the sum of thicknesses of the solid boron oxide layer and liquid boron oxide layer should be at least 50 .mu.m.

  7. Rational Design and Preparation of Organic Semiconductors for use in Field Effect Transistors and Photovoltaic Cells

    E-Print Network [OSTI]

    Mauldin, Clayton Edward

    2010-01-01T23:59:59.000Z

    Distyryl Oligothiophene Semiconductors Abstract We describebonded Oligothiophene Semiconductor Side Chains Abstract Ato assemble oligothiophene semiconductors and control their

  8. Back-side readout semiconductor photomultiplier

    DOE Patents [OSTI]

    Choong, Woon-Seng; Holland, Stephen E

    2014-05-20T23:59:59.000Z

    This disclosure provides systems, methods, and apparatus related to semiconductor photomultipliers. In one aspect, a device includes a p-type semiconductor substrate, the p-type semiconductor substrate having a first side and a second side, the first side of the p-type semiconductor substrate defining a recess, and the second side of the p-type semiconductor substrate being doped with n-type ions. A conductive material is disposed in the recess. A p-type epitaxial layer is disposed on the second side of the p-type semiconductor substrate. The p-type epitaxial layer includes a first region proximate the p-type semiconductor substrate, the first region being implanted with p-type ions at a higher doping level than the p-type epitaxial layer, and a second region disposed on the first region, the second region being doped with p-type ions at a higher doping level than the first region.

  9. Measuring Speedy Electrons in Silicon

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

    scientists have taken snapshots of this very brief band-gap jump and timed it at 450 attoseconds. Image: Stephen Leone The entire semiconductor industry, not to mention...

  10. PHYSICAL REVIEW B 90, 115415 (2014) Geometrically induced transitions between semimetal and semiconductor in graphene

    E-Print Network [OSTI]

    Wu, Zhigang

    and semiconductor in graphene Marc Dvorak and Zhigang Wu* Department of Physics, Colorado School of Mines, Golden of graphene remains an outstanding problem in nanoscience, which precludes the practical method of patterning graphene from being widely adopted for making graphene-based electronic and optoelectronic devices, because

  11. Nonadiabatic electron transfer at the nanoscale tin-oxide semiconductor/aqueous solution interface

    E-Print Network [OSTI]

    published as an Advance Article on the web 28th January 2004 Photo-excitation of chromophoric metal forward and back electron transfer reactions involving molecular dyes and wide bandgap semiconductors words, electro- nic coupling rather than nuclear motion appears to govern the reaction dynamics

  12. Semiconductor lasers with broad tunnel-coupled waveguides, emitting at a wavelength of 980 nm

    SciTech Connect (OSTI)

    Zvonkov, N B; Ershov, A V; Zvonkov, B N; Maksimov, G A; Uskova, E A [Scientific-Research Physicotechnical Institute at the Nizhnii Novgorod State University, Nizhnii Novgorod (Russian Federation); Akhlestina, S A [Research Insitute of Chemistry, N.I. Lobachevskii Nizhnii Novgorod State University, Nizhnii Novgorod (Russian Federation)

    1999-03-31T23:59:59.000Z

    InGaP/GaAs/InGaAs semiconductor lasers with broad tunnel-coupled waveguides were developed and investigated experimentally. Output radiation power of 5.2 - 5.8 W was obtained from an emitting region 100 {mu}m wide with a 36{sup 0} divergence of the emitted radiation in a plane perpendicular to the p - n junction. (lasers)

  13. Wide Angle Compton Scattering

    E-Print Network [OSTI]

    Rainer Jakob

    2000-10-16T23:59:59.000Z

    We present the handbag contribution to Wide Angle Compton Scattering (WACS) at moderately large momentum transfer obtained with a proton distribution amplitude close to the asymptotic form. In comparison it is found to be significantly larger than results from the hard scattering (pQCD) approach.

  14. Lateral coupled cavity semiconductor laser

    SciTech Connect (OSTI)

    Salzman, J.; Lang, R.; Yariv, A.

    1985-08-01T23:59:59.000Z

    We report the fabrication and operation of a lateral coupled cavity semiconductor laser that consists of two phase-locked parallel lasers of different lengths and with separate electrical contacts. Mode selectivity that results from the interaction between the two supermodes is investigated experimentally. Frequency selectivity and tunability are obtained by controlling the current to each laser separately. Highly stable single mode operation is also demonstrated.

  15. Compound semiconductor optical waveguide switch

    DOE Patents [OSTI]

    Spahn, Olga B.; Sullivan, Charles T.; Garcia, Ernest J.

    2003-06-10T23:59:59.000Z

    An optical waveguide switch is disclosed which is formed from III-V compound semiconductors and which has a moveable optical waveguide with a cantilevered portion that can be bent laterally by an integral electrostatic actuator to route an optical signal (i.e. light) between the moveable optical waveguide and one of a plurality of fixed optical waveguides. A plurality of optical waveguide switches can be formed on a common substrate and interconnected to form an optical switching network.

  16. Routing for analog chip design at NXP semiconductors

    E-Print Network [OSTI]

    Utrecht, Universiteit

    Routing for analog chip design at NXP semiconductors Marjan van den Akker Theo Beelen Rob H.O. Box 80.089 3508 TB Utrecht The Netherlands #12;Routing for analog chip designs at NXP Semiconductors.1 NXP Semiconductors NXP Semiconductors N.V. (Nasdaq: NXPI) is a global semiconductor company and a long

  17. Fundamental lateral mode oscillation via gain tailoring in broad area semiconductor lasers

    SciTech Connect (OSTI)

    Lindsey, C.; Derry, P.; Yariv, A.

    1985-09-15T23:59:59.000Z

    We show that by employing gain tailoring in a broad area semiconductor laser we achieve fundamental lateral mode operation with a diffraction-limited single-lobed far-field pattern. We demonstrate a tailored gain broad area laser 60 ..mu..m wide which emits 450 mW per mirror into a stable, single-lobed far-field pattern 3 1/2/sup 0/ wide at 5.3 I/sub th/.

  18. Optical devices featuring textured semiconductor layers

    DOE Patents [OSTI]

    Moustakas, Theodore D. (Dover, MA); Cabalu, Jasper S. (Cary, NC)

    2012-08-07T23:59:59.000Z

    A semiconductor sensor, solar cell or emitter, or a precursor therefor, has a substrate and one or more textured semiconductor layers deposited onto the substrate. The textured layers enhance light extraction or absorption. Texturing in the region of multiple quantum wells greatly enhances internal quantum efficiency if the semiconductor is polar and the quantum wells are grown along the polar direction. Electroluminescence of LEDs of the invention is dichromatic, and results in variable color LEDs, including white LEDs, without the use of phosphor.

  19. Optical devices featuring textured semiconductor layers

    DOE Patents [OSTI]

    Moustakas, Theodore D. (Dover, MA); Cabalu, Jasper S. (Cary, NC)

    2011-10-11T23:59:59.000Z

    A semiconductor sensor, solar cell or emitter, or a precursor therefor, has a substrate and one or more textured semiconductor layers deposited onto the substrate. The textured layers enhance light extraction or absorption. Texturing in the region of multiple quantum wells greatly enhances internal quantum efficiency if the semiconductor is polar and the quantum wells are grown along the polar direction. Electroluminescence of LEDs of the invention is dichromatic, and results in variable color LEDs, including white LEDs, without the use of phosphor.

  20. Phase-locked semiconductor laser array with separate contacts

    SciTech Connect (OSTI)

    Katz, J.; Kapon, E.; Lindsey, C.; Margalit, S.; Shreter, U.; Yariv, A.

    1983-09-15T23:59:59.000Z

    A new monolithic phase-locked semiconductor laser array has been fabricated. Employing two-level metallization, each of the eight elements in the array has a separate contact, thus making it possible to compensate for device nonuniformities and control the near-field and far-field patterns. Threshold currents are approximately 60 mA for each 5-..mu..m-wide laser in the array. Phase locking has been observed via the narrowing of the far-field pattern. Experimental results are compared to those obtained from the same arrays operated with all the lasers connected in parallel.

  1. Optical Nonlinearities and Ultrafast Carrier Dynamics in Semiconductor Quantum Dots

    SciTech Connect (OSTI)

    Klimov, V.; McBranch, D.; Schwarz, C.

    1998-08-10T23:59:59.000Z

    Low-dimensional semiconductors have attracted great interest due to the potential for tailoring their linear and nonlinear optical properties over a wide-range. Semiconductor nanocrystals (NC's) represent a class of quasi-zero-dimensional objects or quantum dots. Due to quantum cordhement and a large surface-to-volume ratio, the linear and nonlinear optical properties, and the carrier dynamics in NC's are significantly different horn those in bulk materials. napping at surface states can lead to a fast depopulation of quantized states, accompanied by charge separation and generation of local fields which significantly modifies the nonlinear optical response in NC's. 3D carrier confinement also has a drastic effect on the energy relaxation dynamics. In strongly confined NC's, the energy-level spacing can greatly exceed typical phonon energies. This has been expected to significantly inhibit phonon-related mechanisms for energy losses, an effect referred to as a phonon bottleneck. It has been suggested recently that the phonon bottleneck in 3D-confined systems can be removed due to enhanced role of Auger-type interactions. In this paper we report femtosecond (fs) studies of ultrafast optical nonlinearities, and energy relaxation and trap ping dynamics in three types of quantum-dot systems: semiconductor NC/glass composites made by high temperature precipitation, ion-implanted NC's, and colloidal NC'S. Comparison of ultrafast data for different samples allows us to separate effects being intrinsic to quantum dots from those related to lattice imperfections and interface properties.

  2. Low Energy Ion Implantationin Semiconductor Manufacturing | U...

    Office of Science (SC) Website

    Low Energy Ion Implantation in Semiconductor Manufacturing Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Applications of Nuclear Science...

  3. Climate VISION: Private Sector Initiatives: Semiconductors: Work...

    Office of Scientific and Technical Information (OSTI)

    of EPA. The plan describes actions the industry intends to take to achieve its Climate VISION goal by 2010. Read the Semiconductor Industry Association Work Plan (PDF 94...

  4. Climate VISION: Private Sector Initiatives: Semiconductors: Resources...

    Office of Scientific and Technical Information (OSTI)

    to reduce high global warming potential (GWP) greenhouse gas emissions by following a pollution prevention strategy. Today, nearly 80 percent of U.S. semiconductor manufacturers...

  5. Isovalent Anion Substitution in Ga-Mn-pnictide Ferromagnetic Semiconductors

    E-Print Network [OSTI]

    Stone, Peter

    2010-01-01T23:59:59.000Z

    a so-called diluted magnetic semiconductor (DMS). DMSs arein heavily doped magnetic semiconductors as the probabilitythis method to magnetic semiconductors, the 6×6 k·p matrix

  6. Performance of Adaptive DualDropping ILUT Preconditioners in Semiconductor

    E-Print Network [OSTI]

    Zhang, Jun

    Performance of Adaptive Dual­Dropping ILUT Preconditioners in Semiconductor Dopant Diffusion for iterative solution of sparse linear systems arising in semiconductor dopant diffusion modeling resolution, timestep in the adaptive ODE integrator and the problem physics. Key words: semiconductor TCAD

  7. OPTI 240: Semiconductor Physics and Lasers Instructor: Mahmoud Fallahi

    E-Print Network [OSTI]

    Arizona, University of

    OPTI 240: Semiconductor Physics and Lasers Instructor: Mahmoud Fallahi fallahi@optics.arizona.edu Spring Semester Introduction to Semiconductor Optoelectronic Introduction to quantum mechanics: Energy exclusion principle Metal, Insulator, Semiconductor Conduction band, valance band, energy gap Electrons

  8. Semiconductor Capabilities in the U.S. and Industrializing Asia

    E-Print Network [OSTI]

    Brown, Clair; Linden, Greg

    2008-01-01T23:59:59.000Z

    data. Table 2: U.S. Semiconductor Engineers By Location,medium-sized U.S. semiconductor companies, which togetherto represent all U.S. semiconductor firms. The total

  9. Ann. N.Y. Acad. Sci. 1006: 104121 (2003). 2003 New York Academy of Sciences. doi: 10.1196/annals.1292.007

    E-Print Network [OSTI]

    Zhou, Chongwu

    2003-01-01T23:59:59.000Z

    semiconductor nanowires, semiconducting oxide nanowires, such as ZnO, CdO, and In2O3 are becoming increasingly cells and organic light emitting diodes.13,14 More importantly, In2O3 films have been demonstrated.6eV and an indirect band gap of about 2.5eV). In2O3 in the bulk form has been widely used in solar

  10. Downloaded 03 Apr 2013 to 147.173.59.170. This article is copyrighted as indicated in the abstract. Reuse of AIP content is subject to the terms at: http://apl.aip.org/about/rights_and_permissions High conductivity in Si-doped GaN wires

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ;High conductivity in Si-doped GaN wires P. Tchoulfian,1,2,a) F. Donatini,2 F. Levy,1 B. Amstatt,1 P-dependent resistivity measurements have been performed on single Si-doped GaN microwires grown by catalyst-free metal.1063/1.4799167] GaN is a wide band gap III-V semiconductor ($3.4 eV) currently used as the basic material for planar

  11. PROTECTIVE SURFACE COATINGS ON SEMICONDUCTOR NUCLEAR RADIATION DETECTORS

    E-Print Network [OSTI]

    Hansen, W.L.

    2010-01-01T23:59:59.000Z

    ON SEMICONDUCTOR NUCLEAR RADIATION DETECTORS W. L. Hansen,COATINGS ON SEMICONDUCTOR NUCLEAR RADIATION DETECTORS* W. L.the use of germanium nuclear radiation detec­ tors, a new

  12. New ALS Technique Guides IBM in Next-Generation Semiconductor...

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

    New ALS Technique Guides IBM in Next-Generation Semiconductor Development New ALS Technique Guides IBM in Next-Generation Semiconductor Development Print Wednesday, 21 January 2015...

  13. Hydrogenated Graphene Nanoflakes: Semiconductor to Half-Metal...

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

    Hydrogenated Graphene Nanoflakes: Semiconductor to Half-Metal Transition and Remarkable Large Magnetism. Hydrogenated Graphene Nanoflakes: Semiconductor to Half-Metal Transition...

  14. Engineering Density of States of Earth Abundant Semiconductors...

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

    of States of Earth Abundant Semiconductors for Enhanced Thermoelectric Power Factor Engineering Density of States of Earth Abundant Semiconductors for Enhanced Thermoelectric...

  15. advanced semiconductor manufacturing: Topics by E-print Network

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

    Websites Summary: Business and Manufacturing Tohru Ogawa Semiconductor Company Sony Corporation 12;WISE 2000 ContentsContents Paradigm Shift in Semiconductor Business...

  16. Charge-carrier transport in amorphous organic semiconductors

    E-Print Network [OSTI]

    Limketkai, Benjie, 1982-

    2008-01-01T23:59:59.000Z

    Since the first reports of efficient luminescence and absorption in organic semiconductors, organic light-emitting devices (OLEDs) and photovoltaics (OPVs) have attracted increasing interest. Organic semiconductors have ...

  17. Optic probe for semiconductor characterization

    DOE Patents [OSTI]

    Sopori, Bhushan L. (Denver, CO); Hambarian, Artak (Yerevan, AM)

    2008-09-02T23:59:59.000Z

    Described herein is an optical probe (120) for use in characterizing surface defects in wafers, such as semiconductor wafers. The optical probe (120) detects laser light reflected from the surface (124) of the wafer (106) within various ranges of angles. Characteristics of defects in the surface (124) of the wafer (106) are determined based on the amount of reflected laser light detected in each of the ranges of angles. Additionally, a wafer characterization system (100) is described that includes the described optical probe (120).

  18. Influence of grain boundary modification on limited performance of wide bandgap Cu(In,Ga)Se{sub 2} solar cells

    SciTech Connect (OSTI)

    Raghuwanshi, M., E-mail: mohit.raghuwanshi@etu.univ-rouen.fr; Cadel, E.; Pareige, P.; Duguay, S. [Groupe de Physique des Materiaux (GPM), UMR 6634 CNRS, Université et INSA de Rouen, Avenue de l'Universite BP 12, 76801 Saint Etienne du Rouvray (France); Couzinie-Devy, F.; Arzel, L.; Barreau, N. [Institut des Materiaux Jean Rouxel (IMN), UMR 6502 CNRS, Université de Nantes, 2 rue de la Houssiniere BP 32229, 44322 Nantes cedex 3 (France)

    2014-07-07T23:59:59.000Z

    The reason why so-called wide-bandgap CuIn{sub 1?x}Ga{sub x}Se{sub 2} (CIGSe with x?>?0.4) based solar cells show hindered performance compared with theoretical expectations is still a matter of debate. In the present Letter, atom probe tomography studies of CuIn{sub 1?x}Ga{sub x}Se{sub 2} polycrystalline thin films with x varying from 0 to 1 are reported. These investigations confirm that the grain boundaries (GBs) of low gallium containing (x?band gap CIGSe films (x?>?0.8) are Cu-enriched compared with GI. For intermediate gallium contents (0.4?

  19. 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.

  20. Nonlinear Peltier effect in semiconductors Mona Zebarjadia

    E-Print Network [OSTI]

    Nonlinear Peltier effect in semiconductors Mona Zebarjadia Department of Electrical Engineering; published online 18 September 2007 Nonlinear Peltier coefficient of a doped InGaAs semiconductor is calculated numerically using the Monte Carlo technique. The Peltier coefficient is also obtained analytically

  1. Preparation of a semiconductor thin film

    DOE Patents [OSTI]

    Pehnt, M.; Schulz, D.L.; Curtis, C.J.; Ginley, D.S.

    1998-01-27T23:59:59.000Z

    A process is disclosed for the preparation of a semiconductor film. The process comprises depositing nanoparticles of a semiconductor material onto a substrate whose surface temperature during nanoparticle deposition thereon is sufficient to cause substantially simultaneous fusion of the nanoparticles to thereby coalesce with each other and effectuate film growth.

  2. Ultra-high speed semiconductor lasers

    SciTech Connect (OSTI)

    Lau, K.Y.; Yariv, A.

    1985-02-01T23:59:59.000Z

    Recent progress on semiconductor lasers having a very high direct modulation bandwidth of beyond 10 GHz are described. Issues related to application of these lasers in actual systems are addressed. Possibilities of further extending the bandwidth of semiconductor lasers are examined.

  3. Preparation of a semiconductor thin film

    DOE Patents [OSTI]

    Pehnt, Martin (TuBingen, DE); Schulz, Douglas L. (Denver, CO); Curtis, Calvin J. (Lakewood, CO); Ginley, David S. (Evergreen, CO)

    1998-01-01T23:59:59.000Z

    A process for the preparation of a semiconductor film. The process comprises depositing nanoparticles of a semiconductor material onto a substrate whose surface temperature during nanoparticle deposition thereon is sufficient to cause substantially simultaneous fusion of the nanoparticles to thereby coalesce with each other and effectuate film growth.

  4. Stable surface passivation process for compound semiconductors

    DOE Patents [OSTI]

    Ashby, Carol I. H. (Edgewood, NM)

    2001-01-01T23:59:59.000Z

    A passivation process for a previously sulfided, selenided or tellurated III-V compound semiconductor surface. The concentration of undesired mid-gap surface states on a compound semiconductor surface is reduced by the formation of a near-monolayer of metal-(sulfur and/or selenium and/or tellurium)-semiconductor that is effective for long term passivation of the underlying semiconductor surface. Starting with the III-V compound semiconductor surface, any oxidation present thereon is substantially removed and the surface is then treated with sulfur, selenium or tellurium to form a near-monolayer of chalcogen-semiconductor of the surface in an oxygen-free atmosphere. This chalcogenated surface is then contacted with a solution of a metal that will form a low solubility chalcogenide to form a near-monolayer of metal-chalcogen-semiconductor. The resulting passivating layer provides long term protection for the underlying surface at or above the level achieved by a freshly chalcogenated compound semiconductor surface in an oxygen free atmosphere.

  5. Hybrid anode for semiconductor radiation detectors

    DOE Patents [OSTI]

    Yang, Ge; Bolotnikov, Aleksey E; Camarda, Guiseppe; Cui, Yonggang; Hossain, Anwar; Kim, Ki Hyun; James, Ralph B

    2013-11-19T23:59:59.000Z

    The present invention relates to a novel hybrid anode configuration for a radiation detector that effectively reduces the edge effect of surface defects on the internal electric field in compound semiconductor detectors by focusing the internal electric field of the detector and redirecting drifting carriers away from the side surfaces of the semiconductor toward the collection electrode(s).

  6. Semiconductor switch geometry with electric field shaping

    DOE Patents [OSTI]

    Booth, Rex (Livermore, CA); Pocha, Michael D. (Livermore, CA)

    1994-01-01T23:59:59.000Z

    An optoelectric switch is disclosed that utilizes a cylindrically shaped and contoured GaAs medium or other optically active semiconductor medium to couple two cylindrically shaped metal conductors with flat and flared termination points each having an ovoid prominence centrally extending there from. Coupling the truncated ovoid prominence of each conductor with the cylindrically shaped optically active semiconductor causes the semiconductor to cylindrically taper to a triple junction circular line at the base of each prominence where the metal conductor conjoins with the semiconductor and a third medium such as epoxy or air. Tapering the semiconductor at the triple junction inhibits carrier formation and injection at the triple junction and thereby enables greater current carrying capacity through and greater sensitivity of the bulk area of the optically active medium.

  7. Semiconductor switch geometry with electric field shaping

    DOE Patents [OSTI]

    Booth, R.; Pocha, M.D.

    1994-08-23T23:59:59.000Z

    An optoelectric switch is disclosed that utilizes a cylindrically shaped and contoured GaAs medium or other optically active semiconductor medium to couple two cylindrically shaped metal conductors with flat and flared termination points each having an ovoid prominence centrally extending there from. Coupling the truncated ovoid prominence of each conductor with the cylindrically shaped optically active semiconductor causes the semiconductor to cylindrically taper to a triple junction circular line at the base of each prominence where the metal conductor conjoins with the semiconductor and a third medium such as epoxy or air. Tapering the semiconductor at the triple junction inhibits carrier formation and injection at the triple junction and thereby enables greater current carrying capacity through and greater sensitivity of the bulk area of the optically active medium. 10 figs.

  8. L{sub g}?=?100?nm In{sub 0.7}Ga{sub 0.3}As quantum well metal-oxide semiconductor field-effect transistors with atomic layer deposited beryllium oxide as interfacial layer

    SciTech Connect (OSTI)

    Koh, D., E-mail: dh.koh@utexas.edu, E-mail: Taewoo.Kim@sematech.org [Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin, Austin, Texas 78758 (United States); SEMATECH, Inc., Albany, New York 12203 (United States); Kwon, H. M. [Department of Electronics Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Kim, T.-W., E-mail: dh.koh@utexas.edu, E-mail: Taewoo.Kim@sematech.org; Veksler, D.; Gilmer, D.; Kirsch, P. D. [SEMATECH, Inc., Albany, New York 12203 (United States); Kim, D.-H. [SEMATECH, Inc., Albany, New York 12203 (United States); GLOBALFOUNDRIES, Malta, New York 12020 (United States); Hudnall, Todd W. [Department of Chemistry and Biochemistry, Texas State University, San Marcos, Texas, 78666 (United States); Bielawski, Christopher W. [Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712 (United States); Maszara, W. [GLOBALFOUNDRIES, Santa Clara, California 95054 (United States); Banerjee, S. K. [Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin, Austin, Texas 78758 (United States)

    2014-04-21T23:59:59.000Z

    In this study, we have fabricated nanometer-scale channel length quantum-well (QW) metal-oxide-semiconductor field effect transistors (MOSFETs) incorporating beryllium oxide (BeO) as an interfacial layer. BeO has high thermal stability, excellent electrical insulating characteristics, and a large band-gap, which make it an attractive candidate for use as a gate dielectric in making MOSFETs. BeO can also act as a good diffusion barrier to oxygen owing to its small atomic bonding length. In this work, we have fabricated In{sub 0.53}Ga{sub 0.47}As MOS capacitors with BeO and Al{sub 2}O{sub 3} and compared their electrical characteristics. As interface passivation layer, BeO/HfO{sub 2} bilayer gate stack presented effective oxide thickness less 1 nm. Furthermore, we have demonstrated In{sub 0.7}Ga{sub 0.3}As QW MOSFETs with a BeO/HfO{sub 2} dielectric, showing a sub-threshold slope of 100?mV/dec, and a transconductance (g{sub m,max}) of 1.1 mS/?m, while displaying low values of gate leakage current. These results highlight the potential of atomic layer deposited BeO for use as a gate dielectric or interface passivation layer for III–V MOSFETs at the 7?nm technology node and/or beyond.

  9. Investigation of the basic physics of high efficiency semiconductor hot carrier solar cell. Annual status report, 31 May 1994-30 May 1995

    SciTech Connect (OSTI)

    Alfano, R.R.; Wang, W.B.; Mohaidat, J.M.; Cavicchia, M.A.; Raisky, O.Y.

    1995-05-01T23:59:59.000Z

    The main purpose of this research program is to investigate potential semiconductor materials and their multi-band-gap MQW (multiple quantum wells) structures for high efficiency solar cells for aerospace and commercial applications. The absorption and PL (photoluminescence) spectra, the carrier dynamics, and band structures have been investigated for semiconductors of InP, GaP, GaInP, and InGaAsP/InP MQW structures, and for semiconductors of GaAs and AlGaAs by previous measurements. The barrier potential design criteria for achieving maximum energy conversion efficiency, and the resonant tunneling time as a function of barrier width in high efficiency MQW solar cell structures have also been investigated in the first two years. Based on previous carrier dynamics measurements and the time-dependent short circuit current density calculations, an InAs/InGaAs - InGaAs/GaAs - GaAs/AlGaAs MQW solar cell structure with 15 bandgaps has been designed. The absorption and PL spectra in InGaAsP/InP bulk and MQW structures were measured at room temperature and 77 K with different pump wavelength and intensity, to search for resonant states that may affect the solar cell activities. Time-resolved IR absorption for InGaAsP/InP bulk and MQW structures has been measured by femtosecond visible-pump and IR-probe absorption spectroscopy. This, with the absorption and PL measurements, will be helpful to understand the basic physics and device performance in multi-bandgap InAs/InGaAs - InGaAs/InP - InP/InGaP MQW solar cells. In particular, the lifetime of the photoexcited hot electrons is an important parameter for the device operation of InGaAsP/InP MQW solar cells working in the resonant tunneling conditions. Lastly, time evolution of the hot electron relaxation in GaAs has been measured in the temperature range of 4 K through 288 K using femtosecond pump-IR-probe absorption technique.

  10. Inorganic Chemistry Solutions to Semiconductor Nanocrystal Problems

    SciTech Connect (OSTI)

    Alvarado, Samuel R. [Ames Laboratory; Guo, Yijun [Ames Laboratory; Ruberu, T. Purnima A. [Ames Laboratory; Tavasoli, Elham [Ames Laboratory; Vela, Javier [Ames Laboratory

    2014-03-15T23:59:59.000Z

    The optoelectronic and chemical properties of semiconductor nanocrystals heavily depend on their composition, size, shape and internal structure, surface functionality, etc. Available strategies to alter these properties through traditional colloidal syntheses and ligand exchange methods place a premium on specific reaction conditions and surfactant combinations. In this invited review, we apply a molecular-level understanding of chemical precursor reactivity to reliably control the morphology, composition and intimate architecture (core/shell vs. alloyed) of semiconductor nanocrystals. We also describe our work aimed at achieving highly selective, low-temperature photochemical methods for the synthesis of semiconductor–metal and semiconductor–metal oxide photocatalytic nanocomposites. In addition, we describe our work on surface modification of semiconductor nanocrystal quantum dots using new approaches and methods that bypass ligand exchange, retaining the nanocrystal's native ligands and original optical properties, as well as on spectroscopic methods of characterization useful in determining surface ligand organization and chemistry. Using recent examples from our group and collaborators, we demonstrate how these efforts have lead to faster, wider and more systematic application of semiconductor nanocrystal-based materials to biological imaging and tracking, and to photocatalysis of unconventional substrates. We believe techniques and methods borrowed from inorganic chemistry (including coordination, organometallic and solid state chemistry) have much to offer in reaching a better understanding of the synthesis, functionalization and real-life application of such exciting materials as semiconductor nanocrystals (quantum dots, rods, tetrapods, etc.).

  11. Thin film solar cell including a spatially modulated intrinsic layer

    DOE Patents [OSTI]

    Guha, Subhendu (Troy, MI); Yang, Chi-Chung (Troy, MI); Ovshinsky, Stanford R. (Bloomfield Hills, MI)

    1989-03-28T23:59:59.000Z

    One or more thin film solar cells in which the intrinsic layer of substantially amorphous semiconductor alloy material thereof includes at least a first band gap portion and a narrower band gap portion. The band gap of the intrinsic layer is spatially graded through a portion of the bulk thickness, said graded portion including a region removed from the intrinsic layer-dopant layer interfaces. The band gap of the intrinsic layer is always less than the band gap of the doped layers. The gradation of the intrinsic layer is effected such that the open circuit voltage and/or the fill factor of the one or plural solar cell structure is enhanced.

  12. Transport Equations for Semiconductors Prof. Dr. Ansgar Jungel

    E-Print Network [OSTI]

    Jüngel, Ansgar

    - cations have been invented; for instance, semiconductor lasers, solar cells, light-emitting diodes (LED

  13. Kinetic and Macroscopic Models for Semiconductors Ansgar Jungel

    E-Print Network [OSTI]

    Jüngel, Ansgar

    Kinetic and Macroscopic Models for Semiconductors Ansgar J¨ungel Vienna University of Technology, Austria www.jungel.at.vu Ansgar J¨ungel (TU Wien) Kinetic Semiconductor Models www.jungel.at.vu 1 / 165 #12;Contents 1 Introduction 2 Semiconductor modeling Basics of semiconductor physics Kinetic models 3

  14. EEE 6397 Semiconductor Device Theory (Fall, 2014, 5th

    E-Print Network [OSTI]

    Fang, Yuguang "Michael"

    1 EEE 6397 Semiconductor Device Theory (Fall, 2014, 5th period MWF, BEN328) Goals: (1) Develop fundamental understanding on the device physics of the most important semiconductor devices, such as PN junctions, metal-semiconductor contacts, metal-oxide-semiconductor capacitors, and field-effect transistors

  15. Heating device for semiconductor wafers

    DOE Patents [OSTI]

    Vosen, S.R.

    1999-07-27T23:59:59.000Z

    An apparatus for heat treating semiconductor wafers is disclosed. The apparatus includes a heating device which contains an assembly of light energy sources for emitting light energy onto a wafer. In particular, the light energy sources are positioned such that many different radial heating zones are created on a wafer being heated. For instance, in one embodiment, the light energy sources form a spiral configuration. In an alternative embodiment, the light energy sources appear to be randomly dispersed with respect to each other so that no discernible pattern is present. In a third alternative embodiment of the present invention, the light energy sources form concentric rings. Tuning light sources are then placed in between the concentric rings of light. 4 figs.

  16. Heating device for semiconductor wafers

    DOE Patents [OSTI]

    Vosen, Steven R. (Berkeley, CA)

    1999-01-01T23:59:59.000Z

    An apparatus for heat treating semiconductor wafers is disclosed. The apparatus includes a heating device which contains an assembly of light energy sources for emitting light energy onto a wafer. In particular, the light energy sources are positioned such that many different radial heating zones are created on a wafer being heated. For instance, in one embodiment, the light energy sources form a spiral configuration. In an alternative embodiment, the light energy sources appear to be randomly dispersed with respect to each other so that no discernable pattern is present. In a third alternative embodiment of the present invention, the light energy sources form concentric rings. Tuning light sources are then placed in between the concentric rings of light.

  17. Diluted magnetic semiconductor nanowires exhibiting magnetoresistance

    DOE Patents [OSTI]

    Yang, Peidong (El Cerrito, CA); Choi, Heonjin (Seoul, KR); Lee, Sangkwon (Daejeon, KR); He, Rongrui (Albany, CA); Zhang, Yanfeng (El Cerrito, CA); Kuykendal, Tevye (Berkeley, CA); Pauzauskie, Peter (Berkeley, CA)

    2011-08-23T23:59:59.000Z

    A method for is disclosed for fabricating diluted magnetic semiconductor (DMS) nanowires by providing a catalyst-coated substrate and subjecting at least a portion of the substrate to a semiconductor, and dopant via chloride-based vapor transport to synthesize the nanowires. Using this novel chloride-based chemical vapor transport process, single crystalline diluted magnetic semiconductor nanowires Ga.sub.1-xMn.sub.xN (x=0.07) were synthesized. The nanowires, which have diameters of .about.10 nm to 100 nm and lengths of up to tens of micrometers, show ferromagnetism with Curie temperature above room temperature, and magnetoresistance up to 250 Kelvin.

  18. Impact of GaN cap on charges in Al?O?/(GaN/)AlGaN/GaN metal-oxide-semiconductor heterostructures analyzed by means of capacitance measurements and simulations

    SciTech Connect (OSTI)

    ?apajna, M., E-mail: milan.tapajna@savba.sk; Jurkovi?, M.; Válik, L.; Haš?ík, Š.; Gregušová, D.; Kuzmík, J. [Institute of Electrical Engineering, Slovak Academy of Sciences, Dúbravská cesta 9, 841 04 Bratislava (Slovakia); Brunner, F.; Cho, E.-M. [Ferdinand-Braun-Institut, Leibniz Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Strasse 4, 12489 Berlin (Germany); Hashizume, T. [Research Center for Integrated Quantum Electronics (RCIQE), Hokkaido University, 060-0814 Sapporo, Japan and JST-CREST, 102-0075 Tokyo (Japan)

    2014-09-14T23:59:59.000Z

    Oxide/semiconductor interface trap density (D{sub it}) and net charge of Al?O?/(GaN)/AlGaN/GaN metal-oxide-semiconductor high-electron mobility transistor (MOS-HEMT) structures with and without GaN cap were comparatively analyzed using comprehensive capacitance measurements and simulations. D{sub it} distribution was determined in full band gap of the barrier using combination of three complementary capacitance techniques. A remarkably higher D{sub it} (?5–8?×?10¹²eV?¹?cm?²) was found at trap energies ranging from EC-0.5 to 1?eV for structure with GaN cap compared to that (D{sub it}???2–3?×?10¹²eV?¹?cm?²) where the GaN cap was selectively etched away. D{sub it} distributions were then used for simulation of capacitance-voltage characteristics. A good agreement between experimental and simulated capacitance-voltage characteristics affected by interface traps suggests (i) that very high D{sub it} (>10¹³eV?¹?cm?²) close to the barrier conduction band edge hampers accumulation of free electron in the barrier layer and (ii) the higher D{sub it} centered about EC-0.6?eV can solely account for the increased C-V hysteresis observed for MOS-HEMT structure with GaN cap. Analysis of the threshold voltage dependence on Al?O? thickness for both MOS-HEMT structures suggests that (i) positive charge, which compensates the surface polarization, is not necessarily formed during the growth of III-N heterostructure, and (ii) its density is similar to the total surface polarization charge of the GaN/AlGaN barrier, rather than surface polarization of the top GaN layer only. Some constraints for the positive surface compensating charge are discussed.

  19. Ultraviolet GaN photodetectors on Si via oxide buffer heterostructures with integrated short period oxide-based distributed Bragg reflectors and leakage suppressing metal-oxide-semiconductor contacts

    SciTech Connect (OSTI)

    Szyszka, A., E-mail: szyszka@ihp-microelectronics.com, E-mail: adam.szyszka@pwr.wroc.pl [IHP, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany); Faculty of Microsystem Electronics and Photonics, Wroclaw University of Technology, Janiszewskiego 11/17, 50-372 Wroclaw (Poland); Lupina, L.; Lupina, G.; Schubert, M. A.; Zaumseil, P. [IHP, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany); Haeberlen, M.; Storck, P.; Thapa, S. B. [Siltronic, Hanns-Seidel-Platz 4, 81737 München (Germany); Schroeder, T. [IHP, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany); BTU Cottbus-Senftenberg, Konrad-Zuse-Strasse 1, 03046 Cottbus (Germany)

    2014-08-28T23:59:59.000Z

    Based on a novel double step oxide buffer heterostructure approach for GaN integration on Si, we present an optimized Metal-Semiconductor-Metal (MSM)-based Ultraviolet (UV) GaN photodetector system with integrated short-period (oxide/Si) Distributed Bragg Reflector (DBR) and leakage suppressing Metal-Oxide-Semiconductor (MOS) electrode contacts. In terms of structural properties, it is demonstrated by in-situ reflection high energy electron diffraction and transmission electron microscopy-energy dispersive x-ray studies that the DBR heterostructure layers grow with high thickness homogeneity and sharp interface structures sufficient for UV applications; only minor Si diffusion into the Y{sub 2}O{sub 3} films is detected under the applied thermal growth budget. As revealed by comparative high resolution x-ray diffraction studies on GaN/oxide buffer/Si systems with and without DBR systems, the final GaN layer structure quality is not significantly influenced by the growth of the integrated DBR heterostructure. In terms of optoelectronic properties, it is demonstrated that—with respect to the basic GaN/oxide/Si system without DBR—the insertion of (a) the DBR heterostructures and (b) dark current suppressing MOS contacts enhances the photoresponsivity below the GaN band-gap related UV cut-off energy by almost up to two orders of magnitude. Given the in-situ oxide passivation capability of grown GaN surfaces and the one order of magnitude lower number of superlattice layers in case of higher refractive index contrast (oxide/Si) systems with respect to classical III-N DBR superlattices, virtual GaN substrates on Si via functional oxide buffer systems are thus a promising robust approach for future GaN-based UV detector technologies.

  20. Near-Infrared Photoluminescence Enhancement in Ge/CdS and Ge/ZnS Core/Shell Nanocrystals: Utilizing IV/II-VI Semiconductor Epitaxy

    SciTech Connect (OSTI)

    Guo, Yijun [Ames Laboratory; Rowland, Clare E [Argonne National Laboratory; Schaller, Richard D [Argonne National Laboratory; Vela, Javier [Ames Laboratory

    2014-08-26T23:59:59.000Z

    Ge nanocrystals have a large Bohr radius and a small, size-tunable band gap that may engender direct character via strain or doping. Colloidal Ge nanocrystals are particularly interesting in the development of near-infrared materials for applications in bioimaging, telecommunications and energy conversion. Epitaxial growth of a passivating shell is a common strategy employed in the synthesis of highly luminescent II–VI, III–V and IV–VI semiconductor quantum dots. Here, we use relatively unexplored IV/II–VI epitaxy as a way to enhance the photoluminescence and improve the optical stability of colloidal Ge nanocrystals. Selected on the basis of their relatively small lattice mismatch compared with crystalline Ge, we explore the growth of epitaxial CdS and ZnS shells using the successive ion layer adsorption and reaction method. Powder X-ray diffraction and electron microscopy techniques, including energy dispersive X-ray spectroscopy and selected area electron diffraction, clearly show the controllable growth of as many as 20 epitaxial monolayers of CdS atop Ge cores. In contrast, Ge etching and/or replacement by ZnS result in relatively small Ge/ZnS nanocrystals. The presence of an epitaxial II–VI shell greatly enhances the near-infrared photoluminescence and improves the photoluminescence stability of Ge. Ge/II–VI nanocrystals are reproducibly 1–3 orders of magnitude brighter than the brightest Ge cores. Ge/4.9CdS core/shells show the highest photoluminescence quantum yield and longest radiative recombination lifetime. Thiol ligand exchange easily results in near-infrared active, water-soluble Ge/II–VI nanocrystals. We expect this synthetic IV/II–VI epitaxial approach will lead to further studies into the optoelectronic behavior and practical applications of Si and Ge-based nanomaterials.

  1. Spin injection and manipulation in organic semiconductors

    E-Print Network [OSTI]

    Venkataraman, Karthik (Karthik Raman)

    2011-01-01T23:59:59.000Z

    The use of organic semiconductors to enable organic spintronic devices requires the understanding of transport and control of the spin state of the carriers. This thesis deals with the above issue, focusing on the interface ...

  2. Electrical Usage Characterization of Semiconductor Processing Tools

    E-Print Network [OSTI]

    Hinson, S. R.

    This paper presents the basic concepts in performing an energy and power audit of a semiconductor process tool. A protocol exists that fully describes these measurements and their use and applicability and it will be described. This protocol...

  3. NANOSTRUCTURES, MAGNETIC SEMICONDUCTORS AND SPINELECTRONICS Paata Kervalishvili

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    to data storage, switching, lighting and other devices, can lead to substantially new hardwareNANOSTRUCTURES, MAGNETIC SEMICONDUCTORS AND SPINELECTRONICS Paata Kervalishvili Georgian Technical and manipulation on a nanometre scale, which allows the fabrication of nanostructures with the properties mainly

  4. Surface phonons of III-V semiconductors

    E-Print Network [OSTI]

    Das, Pradip Kumar

    1994-01-01T23:59:59.000Z

    are the simplest of all semiconductor surfaces. Their atomic relaxations and electronic surface states are rather well understood. There have, however, been surprisingly few experimental studies of their vibrational properties, and ours in the first detailed...

  5. Semiconductor-nanocrystal/conjugated polymer thin films

    DOE Patents [OSTI]

    Alivisatos, A. Paul (Oakland, CA); Dittmer, Janke J. (Munich, DE); Huynh, Wendy U. (Munich, DE); Milliron, Delia (Berkeley, CA)

    2010-08-17T23:59:59.000Z

    The invention described herein provides for thin films and methods of making comprising inorganic semiconductor-nanocrystals dispersed in semiconducting-polymers in high loading amounts. The invention also describes photovoltaic devices incorporating the thin films.

  6. EXCITONIC EIGENSTATES OF DISORDERED SEMICONDUCTOR QUANTUM WIRES

    E-Print Network [OSTI]

    of semiconductors are exploited in solar cells, light emitting diodes, and lasers, and, furthermore, future UNIVERSITY OF MINNESOTA 400 Lind Hall 207 Church Street S.E. Minneapolis, Minnesota 55455­0436 Phone: 612

  7. Nanopatterned Electrically Conductive Films of Semiconductor Nanocrystals

    E-Print Network [OSTI]

    Mentzel, Tamar

    We present the first semiconductor nanocrystal films of nanoscale dimensions that are electrically conductive and crack-free. These films make it possible to study the electrical properties intrinsic to the nanocrystals ...

  8. Fabrication of Semiconductors by Wet Chemical Etch

    E-Print Network [OSTI]

    Francoviglia, Laura

    2008-07-01T23:59:59.000Z

    - ern devices. Beginning with Bardeen, Brittain and Shockley’s invention of the transistor in Bell Labs in 1947 and Kilby and Noyce’s introduction of the integrated circuit about a decade later, semiconductor devices have dramat- ically advanced... ad- dition of impurities, their conductivity can be altered. With the need to manu- facture devices at the micro- and nano- scale, the semiconductor industry has followed “Moore’s Law,” the trend that the number of transistors placed...

  9. Optical temperature indicator using thermochromic semiconductors

    DOE Patents [OSTI]

    Kronberg, J.W.

    1995-01-01T23:59:59.000Z

    A reversible optical temperature indicator utilizes thermochromic semiconductors which vary in color in response to various temperature levels. The thermochromic material is enclosed in an enamel which provides protection and prevents breakdown at higher temperatures. Cadmium sulfide is the preferred semiconductor material. The indicator may be utilized as a sign or in a striped arrangement to clearly provide a warning to a user. The various color responses provide multiple levels of alarm.

  10. A Semiconductor Microlaser for Intracavity Flow Cytometry

    SciTech Connect (OSTI)

    Akhil, O.; Copeland, G.C.; Dunne, J.L.; Gourley, P.L.; Hendricks, J.K.; McDonald, A.E.

    1999-01-20T23:59:59.000Z

    Semiconductor microlasers are attractive components for micro-analysis systems because of their ability to emit coherent intense light from a small aperture. By using a surface-emitting semiconductor geometry, we were able to incorporate fluid flow inside a laser microcavity for the first time. This confers significant advantages for high throughput screening of cells, particulates and fluid analytes in a sensitive microdevice. In this paper we discuss the intracavity microfluidics and present preliminary results with flowing blood and brain cells.

  11. Optical temperature sensor using thermochromic semiconductors

    DOE Patents [OSTI]

    Kronberg, James W. (Aiken, SC)

    1998-01-01T23:59:59.000Z

    An optical temperature measuring device utilizes thermochromic semiconductors which vary in color in response to changes in temperature. The thermochromic material is sealed in a glass matrix which allows the temperature sensor to detect high temperatures without breakdown. Cuprous oxide and cadmium sulfide are among the semiconductor materials which provide the best results. The changes in color may be detected visually using a sensor chip and an accompanying color card.

  12. Optical temperature sensor using thermochromic semiconductors

    DOE Patents [OSTI]

    Kronberg, James W. (108 Independent Blvd., Aiken, SC 29801)

    1996-01-01T23:59:59.000Z

    An optical temperature measuring device utilizes thermochromic semiconductors which vary in color in response to changes in temperature. The thermochromic material is sealed in a glass matrix which allows the temperature sensor to detect high temperatures without breakdown. Cuprous oxide and cadmium sulfide are among the semiconductor materials which provide the best results. The changes in color may be detected visually or by utilizing an optical fiber and an electrical sensing circuit.

  13. Optical devices featuring nonpolar textured semiconductor layers

    DOE Patents [OSTI]

    Moustakas, Theodore D; Moldawer, Adam; Bhattacharyya, Anirban; Abell, Joshua

    2013-11-26T23:59:59.000Z

    A semiconductor emitter, or precursor therefor, has a substrate and one or more textured semiconductor layers deposited onto the substrate in a nonpolar orientation. The textured layers enhance light extraction, and the use of nonpolar orientation greatly enhances internal quantum efficiency compared to conventional devices. Both the internal and external quantum efficiencies of emitters of the invention can be 70-80% or higher. The invention provides highly efficient light emitting diodes suitable for solid state lighting.

  14. Optical temperature indicator using thermochromic semiconductors

    DOE Patents [OSTI]

    Kronberg, James W. (108 Independent Blvd., Aiken, SC 29801)

    1996-01-01T23:59:59.000Z

    A reversible optical temperature indicator utilizes thermochromic semiconductors which vary in color in response to various temperature levels. The thermochromic material is enclosed in an enamel which provides protection and prevents breakdown at higher temperatures. Cadmium sulfide is the preferred semiconductor material. The indicator may be utilized as a sign or in a striped arrangement to clearly provide a warning to a user. The various color responses provide multiple levels of alarm.

  15. Optical temperature sensor using thermochromic semiconductors

    DOE Patents [OSTI]

    Kronberg, J.W.

    1996-08-20T23:59:59.000Z

    An optical temperature measuring device utilizes thermochromic semiconductors which vary in color in response to changes in temperature. The thermochromic material is sealed in a glass matrix which allows the temperature sensor to detect high temperatures without breakdown. Cuprous oxide and cadmium sulfide are among the semiconductor materials which provide the best results. The changes in color may be detected visually or by utilizing an optical fiber and an electrical sensing circuit. 7 figs.

  16. Optical temperature sensor using thermochromic semiconductors

    DOE Patents [OSTI]

    Kronberg, J.W.

    1998-06-30T23:59:59.000Z

    An optical temperature measuring device utilizes thermochromic semiconductors which vary in color in response to changes in temperature. The thermochromic material is sealed in a glass matrix which allows the temperature sensor to detect high temperatures without breakdown. Cuprous oxide and cadmium sulfide are among the semiconductor materials which provide the best results. The changes in color may be detected visually using a sensor chip and an accompanying color card. 8 figs.

  17. Goal is to further development and manufacturing of wide bandgap semiconductors

    E-Print Network [OSTI]

    Young, R. Michael

    technology. On Jan. 15, President Barack Obama announced that NC State would lead the Next Generation Power corrections to alumnianddonor_records@ncsu.edu; or call 919.515.7458, toll free: 866.316.4057. NC State

  18. Widely tunable mid-infrared generation via frequency conversion in semiconductor waveguides

    E-Print Network [OSTI]

    of mid-infrared and far-infrared (IR) radiation using second-order optical nonlinearities is attractive, large optical nonlinearities, large optical damage threshold, and mature fabrication tech- nology [3 Optical Society of America OCIS codes: (190.4975) Parametric processes; (230.4320) Nonlinear optical

  19. Opportunities for Wide Bandgap Semiconductor Power Electronics for Hydrogen and Fuel Cell Applications

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn'tOrigin of Contamination in ManyDepartment ofOil'sEnergy 9Industrial Applications -

  20. Ultrafast Control of Magnetism in Ferromagnetic Semiconductors via Photoexcited Transient Carriers

    E-Print Network [OSTI]

    Cotoros, Ingrid A.

    2009-01-01T23:59:59.000Z

    1.2 Overview of semiconductor2.2 Dilute magnetic semiconductors . . . . . . . . .generated holes in (In,Mn)As Magnetic semiconductor FET

  1. Electron gas grid semiconductor radiation detectors

    DOE Patents [OSTI]

    Lee, Edwin Y. (Livermore, CA); James, Ralph B. (Livermore, CA)

    2002-01-01T23:59:59.000Z

    An electron gas grid semiconductor radiation detector (EGGSRAD) useful for gamma-ray and x-ray spectrometers and imaging systems is described. The radiation detector employs doping of the semiconductor and variation of the semiconductor detector material to form a two-dimensional electron gas, and to allow transistor action within the detector. This radiation detector provides superior energy resolution and radiation detection sensitivity over the conventional semiconductor radiation detector and the "electron-only" semiconductor radiation detectors which utilize a grid electrode near the anode. In a first embodiment, the EGGSRAD incorporates delta-doped layers adjacent the anode which produce an internal free electron grid well to which an external grid electrode can be attached. In a second embodiment, a quantum well is formed between two of the delta-doped layers, and the quantum well forms the internal free electron gas grid to which an external grid electrode can be attached. Two other embodiments which are similar to the first and second embodiment involve a graded bandgap formed by changing the composition of the semiconductor material near the first and last of the delta-doped layers to increase or decrease the conduction band energy adjacent to the delta-doped layers.

  2. Spin Transport in Semiconductor heterostructures

    SciTech Connect (OSTI)

    Domnita Catalina Marinescu

    2011-02-22T23:59:59.000Z

    The focus of the research performed under this grant has been the investigation of spin transport in magnetic semiconductor heterostructures. The interest in these systems is motivated both by their intriguing physical properties, as the physical embodiment of a spin-polarized Fermi liquid, as well as by their potential applications as spintronics devices. In our work we have analyzed several different problems that affect the spin dynamics in single and bi-layer spin-polarized two-dimensional (2D) systems. The topics of interests ranged from the fundamental aspects of the electron-electron interactions, to collective spin and charge density excitations and spin transport in the presence of the spin-orbit coupling. The common denominator of these subjects is the impact at the macroscopic scale of the spin-dependent electron-electron interaction, which plays a much more subtle role than in unpolarized electron systems. Our calculations of several measurable parameters, such as the excitation frequencies of magneto-plasma modes, the spin mass, and the spin transresistivity, propose realistic theoretical estimates of the opposite-spin many-body effects, in particular opposite-spin correlations, that can be directly connected with experimental measurements.

  3. Dissipative chaos in semiconductor superlattices

    SciTech Connect (OSTI)

    Alekseev, K.N.; Berman, G.P. [Center for Nonlinear Studies and Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Center for Nonlinear Studies and Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); [Kirensky Institute of Physics, 660036, Krasnoyarsk (Russia); [Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801-3080 (United States); Campbell, D.K.; Cannon, E.H.; Cargo, M.C. [Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801-3080 (United States)] [Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801-3080 (United States)

    1996-10-01T23:59:59.000Z

    We consider the motion of ballistic electrons in a miniband of a semiconductor superlattice (SSL) under the influence of an external, time-periodic electric field. We use a semiclassical, balance-equation approach, which incorporates elastic and inelastic scattering (as dissipation) and the self-consistent field generated by the electron motion. The coupling of electrons in the miniband to the self-consistent field produces a cooperative nonlinear oscillatory mode which, when interacting with the oscillatory external field and the intrinsic Bloch-type oscillatory mode, can lead to complicated dynamics, including dissipative chaos. For a range of values of the dissipation parameters we determine the regions in the amplitude-frequency plane of the external field in which chaos can occur. Our results suggest that for terahertz external fields of the amplitudes achieved by present-day free-electron lasers, chaos may be observable in SSL{close_quote}s. We clarify the nature of this interesting nonlinear dynamics in the superlattice{endash}external-field system by exploring analogies to the Dicke model of an ensemble of two-level atoms coupled with a resonant cavity field, and to Josephson junctions. {copyright} {ital 1996 The American Physical Society.}

  4. Method for removing semiconductor layers from salt substrates

    DOE Patents [OSTI]

    Shuskus, Alexander J. (West Hartford, CT); Cowher, Melvyn E. (East Brookfield, MA)

    1985-08-27T23:59:59.000Z

    A method is described for removing a CVD semiconductor layer from an alkali halide salt substrate following the deposition of the semiconductor layer. The semiconductor-substrate combination is supported on a material such as tungsten which is readily wet by the molten alkali halide. The temperature of the semiconductor-substrate combination is raised to a temperature greater than the melting temperature of the substrate but less than the temperature of the semiconductor and the substrate is melted and removed from the semiconductor by capillary action of the wettable support.

  5. Room temperature triplet state spectroscopy of organic semiconductors

    E-Print Network [OSTI]

    Reineke, Sebastian

    2013-01-01T23:59:59.000Z

    Organic light emitting devices and solar cells are machines that create, manipulate and destroy excited states in organic semiconductors. It is crucial to characterize these excited states, or excitons, to optimize device performance in applications like displays and solar energy harvesting. This is complicated if the excited state is a triplet because the electronic transition is dark with a vanishing oscillator strength. As a consequence, triplet state spectroscopy must usually be performed at cryogenic temperatures to reduce competition from non-radiative rates. Here, we control non-radiative rates by engineering a solid-state host matrix containing the target molecule, allowing the observation of phosphorescence at room temperature and alleviating constraints of cryogenic experiments. We test these techniques on a wide range of materials with functionalities spanning multi-exciton generation (singlet exciton fission), organic light emitting device host materials, and thermally activated delayed fluorescen...

  6. Semiconductor nanowires for photovoltaic and photoelectrochemical energy conversion

    SciTech Connect (OSTI)

    Dasgupta, Neil; Yang, Peidong

    2013-01-23T23:59:59.000Z

    Semiconductor nanowires (NW) possess several beneficial properties for efficient conversion of solar energy into electricity and chemical energy. Due to their efficient absorption of light, short distances for minority carriers to travel, high surface-to-volume ratios, and the availability of scalable synthesis methods, they provide a pathway to address the low cost-to-power requirements for wide-scale adaptation of solar energy conversion technologies. Here we highlight recent progress in our group towards implementation of NW components as photovoltaic and photoelectrochemical energy conversion devices. An emphasis is placed on the unique properties of these one-dimensional (1D) structures, which enable the use of abundant, low-cost materials and improved energy conversion efficiency compared to bulk devices.

  7. Conductance matrix of multiterminal semiconductor devices with edge channels

    SciTech Connect (OSTI)

    Danilovskii, E. Yu., E-mail: danilovskii@mail.ioffe.ru; Bagraev, N. T. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)

    2014-12-15T23:59:59.000Z

    A method for determining the conductance matrix of multiterminal semiconductor structures with edge channels is proposed. The method is based on the solution of a system of linear algebraic equations based on Kirchhoff equations, made up of potential differences U{sub ij} measured at stabilized currents I{sub kl}, where i, j, k, l are terminal numbers. The matrix obtained by solving the system of equations completely describes the structure under study, reflecting its configuration and homogeneity. This method can find wide application when using the known Landauer-Buttiker formalism to analyze carrier transport in the quantum Hall effect and quantum spin Hall effect modes. Within the proposed method, the contribution of the contact area resistances R{sub c} to the formation of conductance matrix elements is taken into account. The possibilities of practical application of the results obtained in developing analog cryptographic devices are considered.

  8. Extracting hot carriers from photoexcited semiconductor nanocrystals

    SciTech Connect (OSTI)

    Zhu, Xiaoyang

    2014-12-10T23:59:59.000Z

    This research program addresses a fundamental question related to the use of nanomaterials in solar energy -- namely, whether semiconductor nanocrystals (NCs) can help surpass the efficiency limits, the so-called “Shockley-Queisser” limit, in conventional solar cells. In these cells, absorption of photons with energies above the semiconductor bandgap generates “hot” charge carriers that quickly “cool” to the band edges before they can be utilized to do work; this sets the solar cell efficiency at a limit of ~31%. If instead, all of the energy of the hot carriers could be captured, solar-to-electric power conversion efficiencies could be increased, theoretically, to as high as 66%. A potential route to capture this energy is to utilize semiconductor nanocrystals. In these materials, the quasi-continuous conduction and valence bands of the bulk semiconductor become discretized due to confinement of the charge carriers. Consequently, the energy spacing between the electronic levels can be much larger than the highest phonon frequency of the lattice, creating a “phonon bottleneck” wherein hot-carrier relaxation is possible via slower multiphonon emission. For example, hot-electron lifetimes as long as ~1 ns have been observed in NCs grown by molecular beam epitaxy. In colloidal NCs, long lifetimes have been demonstrated through careful design of the nanocrystal interfaces. Due to their ability to slow electronic relaxation, semiconductor NCs can in principle enable extraction of hot carriers before they cool to the band edges, leading to more efficient solar cells.

  9. Light sources based on semiconductor current filaments

    DOE Patents [OSTI]

    Zutavern, Fred J. (Albuquerque, NM); Loubriel, Guillermo M. (Albuquerque, NM); Buttram, Malcolm T. (Sandia Park, NM); Mar, Alan (Albuquerque, NM); Helgeson, Wesley D. (Albuquerque, NM); O'Malley, Martin W. (Edgewood, NM); Hjalmarson, Harold P. (Albuquerque, NM); Baca, Albert G. (Albuquerque, NM); Chow, Weng W. (Cedar Crest, NM); Vawter, G. Allen (Albuquerque, NM)

    2003-01-01T23:59:59.000Z

    The present invention provides a new type of semiconductor light source that can produce a high peak power output and is not injection, e-beam, or optically pumped. The present invention is capable of producing high quality coherent or incoherent optical emission. The present invention is based on current filaments, unlike conventional semiconductor lasers that are based on p-n junctions. The present invention provides a light source formed by an electron-hole plasma inside a current filament. The electron-hole plasma can be several hundred microns in diameter and several centimeters long. A current filament can be initiated optically or with an e-beam, but can be pumped electrically across a large insulating region. A current filament can be produced in high gain photoconductive semiconductor switches. The light source provided by the present invention has a potentially large volume and therefore a potentially large energy per pulse or peak power available from a single (coherent) semiconductor laser. Like other semiconductor lasers, these light sources will emit radiation at the wavelength near the bandgap energy (for GaAs 875 nm or near infra red). Immediate potential applications of the present invention include high energy, short pulse, compact, low cost lasers and other incoherent light sources.

  10. Optical spin orientation of a single manganese atom in a semiconductor quantum dot using quasi-resonant excitation

    E-Print Network [OSTI]

    Boyer, Edmond

    of these mem- ories. Dilute magnetic semiconductors (DMS) systems combining semiconductor heterostructures

  11. Antiferromagnetic exchange bias of a ferromagnetic semiconductor by a ferromagnetic metal

    E-Print Network [OSTI]

    Olejnik, K.

    2010-01-01T23:59:59.000Z

    exchange bias of a magnetic semiconductor by a magneticexchange bias in the magnetic semiconductor. The shape and

  12. Semiconductor nanowires for future electronics : growth, characterization, device fabrication, and integration

    E-Print Network [OSTI]

    Dayeh, Shadi A.

    2008-01-01T23:59:59.000Z

    1 1.1 Introduction to Semiconductorin InAs Semiconductor Nanowires. . . . . . . . . . . . .Comparison of different semiconductor NWFETs (non-passivated

  13. 962 IEEE JOURNAL OF PHOTOVOLTAICS, VOL. 4, NO. 3, MAY 2014 Ultrabroadband and Wide-Angle Hybrid

    E-Print Network [OSTI]

    Bowers, John

    962 IEEE JOURNAL OF PHOTOVOLTAICS, VOL. 4, NO. 3, MAY 2014 Ultrabroadband and Wide-Angle Hybrid) are essential to realizing efficiency gains for state-of- the-art multijunction photovoltaic devices approach. Index Terms--Biomimetics, optical films, photovoltaic cells, III­V semiconductor materials. I

  14. Substrate solder barriers for semiconductor epilayer growth

    DOE Patents [OSTI]

    Drummond, T.J.; Ginley, D.S.; Zipperian, T.E.

    1987-10-23T23:59:59.000Z

    During the growth of compound semiconductors by epitaxial processes, substrates are typically mounted to a support. In molecular beam epitaxy, mounting is done using indium as a solder. This method has two drawbacks: the indium reacts with the substrate, and it is difficult to uniformly wet the back of a large diameter substrate. Both of these problems have been successfully overcome by sputter coating the back of the substrate with a thin layer of tungsten carbide or tungsten carbide and gold. In addition to being compatible with the growth of high quality semiconductor epilayers this coating is also inert in all standard substate cleaning etchants used for compound semiconductors, and provides uniform distribution of energy in radiant heating. 1 tab.

  15. Substrate solder barriers for semiconductor epilayer growth

    DOE Patents [OSTI]

    Drummond, Timothy J. (Tijeras, NM); Ginley, David S. (Albuquerque, NM); Zipperian, Thomas E. (Albuquerque, NM)

    1989-01-01T23:59:59.000Z

    During the growth of compound semiconductors by epitaxial processes, substrates are typically mounted to a support. In modular beam epitaxy, mounting is done using indium as a solder. This method has two drawbacks: the indium reacts with the substrate, and it is difficult to uniformly wet the back of a large diameter substrate. Both of these problems have been successfully overcome by sputter coating the back of the substrate with a thin layer of tungsten carbide or tungsten carbide and gold. In addition to being compatible with the growth of high quality semiconductor epilayers this coating is also inert in all standard substrate cleaning etchants used for compound semiconductors, and provides uniform distribution of energy in radiant heating.

  16. Substrate solder barriers for semiconductor epilayer growth

    DOE Patents [OSTI]

    Drummond, T.J.; Ginley, D.S.; Zipperian, T.E.

    1989-05-09T23:59:59.000Z

    During the growth of compound semiconductors by epitaxial processes, substrates are typically mounted to a support. In modular beam epitaxy, mounting is done using indium as a solder. This method has two drawbacks: the indium reacts with the substrate, and it is difficult to uniformly wet the back of a large diameter substrate. Both of these problems have been successfully overcome by sputter coating the back of the substrate with a thin layer of tungsten carbide or tungsten carbide and gold. In addition to being compatible with the growth of high quality semiconductor epilayers this coating is also inert in all standard substrate cleaning etchants used for compound semiconductors, and provides uniform distribution of energy in radiant heating.

  17. 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.

  18. Two-Photon Emission from Semiconductors

    E-Print Network [OSTI]

    Alex Hayat; Pavel Ginzburg; Meir Orenstein

    2007-10-25T23:59:59.000Z

    We report the first experimental observations of two-photon emission from semiconductors, to the best of our knowledge, and develop a corresponding theory for the room-temperature process. Spontaneous two-photon emission is demonstrated in optically-pumped bulk GaAs and in electrically-driven GaInP/AlGaInP quantum wells. Singly-stimulated two-photon emission measurements demonstrate the theoretically predicted two-photon optical gain in semiconductors - a necessary ingredient for any realizations of future two-photon semiconductor lasers. Photon-coincidence experiment validates the simultaneity of the electrically-driven GaInP/AlGaInP two-photon emission, limited only by detector's temporal resolution.

  19. 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.

  20. Electroluminescence in ion gel gated organic polymer semiconductor transistors

    E-Print Network [OSTI]

    Bhat, Shrivalli

    2011-07-12T23:59:59.000Z

    This thesis reports the light emission in ion gel gated, thin film organic semiconductor transistors and investigates the light emission mechanism behind these devices. We report that ion gel gated organic polymer semiconductor transistors emit...

  1. Lattice mismatched compound semiconductors and devices on silicon

    E-Print Network [OSTI]

    Yang, Li, Ph. D. Massachusetts Institute of Technology

    2011-01-01T23:59:59.000Z

    III-V compound semiconductors, due to their superior electron mobility, are promising candidates for n-type metal-oxide-semiconductor field effect transistors (MOSFETs). However, the limited size of III-V substrates and ...

  2. Radio frequency identification (RFID) applications in semiconductor manufacturing

    E-Print Network [OSTI]

    Cassett, David Ian, 1971-

    2004-01-01T23:59:59.000Z

    Radio frequency identification (RFID) has an enormous potential impact within the semiconductor supply chain, especially within semiconductor manufacturing. The end benefit of RFID will be in the mass serialization, and ...

  3. A New Cleanroom for a Next-Generation Semiconductor Research...

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

    A New Cleanroom for a Next-Generation Semiconductor Research Tool A New Cleanroom for a Next-Generation Semiconductor Research Tool Print The new Sector 12 cleanroom under...

  4. A study of corporate entrepreneurship in the semiconductor industry

    E-Print Network [OSTI]

    Tallapureddy, Anish R

    2014-01-01T23:59:59.000Z

    The number of semiconductor companies receiving venture funding has been decreasing through-out the last decade. The economics of manufacturing semiconductors do not offer an attractive risk-reward profile to the traditional ...

  5. 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

  6. High-Throughput Transfer Imprinting for Organic Semiconductors

    E-Print Network [OSTI]

    Choo, Gihoon

    2013-08-06T23:59:59.000Z

    semiconductors because heat and pressure used in thermal nanoimprint do not damage functional materials. However, issues such as residual layer removal and mold contamination still limit the application of nanoimprint for organic semiconductor patterning...

  7. Surface passivation process of compound semiconductor material using UV photosulfidation

    DOE Patents [OSTI]

    Ashby, Carol I. H. (Edgewood, NM)

    1995-01-01T23:59:59.000Z

    A method for passivating compound semiconductor surfaces by photolytically disrupting molecular sulfur vapor with ultraviolet radiation to form reactive sulfur which then reacts with and passivates the surface of compound semiconductors.

  8. Acoustoelectric Harmonic Generation in a Photoconductive Piezoelectric Semiconductor

    E-Print Network [OSTI]

    Acoustoelectric Harmonic Generation in a Photoconductive Piezoelectric Semiconductor W. Arthur, R harmonics in the low frequency regime (. Piezoelectric semiconductors can exhibit harmonic generation because of interactions between the acoustic

  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. 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

  11. 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 ...

  12. 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

  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. 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.

  15. 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

  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. 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.

  20. 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...

  1. Dry etching method for compound semiconductors

    DOE Patents [OSTI]

    Shul, R.J.; Constantine, C.

    1997-04-29T23:59:59.000Z

    A dry etching method is disclosed. According to the present invention, a gaseous plasma comprising, at least in part, boron trichloride, methane, and hydrogen may be used for dry etching of a compound semiconductor material containing layers including aluminum, or indium, or both. Material layers of a compound semiconductor alloy such as AlGaInP or the like may be anisotropically etched for forming electronic devices including field-effect transistors and heterojunction bipolar transistors and for forming photonic devices including vertical-cavity surface-emitting lasers, edge-emitting lasers, and reflectance modulators. 1 fig.

  2. High power semiconductor laser sources. Final report

    SciTech Connect (OSTI)

    Yariv, A.

    1989-01-01T23:59:59.000Z

    The main purpose of the research was to design and fabricate a surface-emitting semiconductor laser based on multi quantum-well amplification. During the contract period, the author succeeded in improving the basic quantum-well active medium so as to result in maximum gain for a given inversion density and analyzed the fabrication of GaAs/GaAlAs multilayer dielectric reflectors for providing the optical feedback to the surface-emitting semiconductor laser. He also made significant progress in the development of diffusion techniques to provide the p and n regions adjacent to the active region for carrier injection.

  3. Dry etching method for compound semiconductors

    DOE Patents [OSTI]

    Shul, Randy J. (Albuquerque, NM); Constantine, Christopher (Safety Harbor, FL)

    1997-01-01T23:59:59.000Z

    A dry etching method. According to the present invention, a gaseous plasma comprising, at least in part, boron trichloride, methane, and hydrogen may be used for dry etching of a compound semiconductor material containing layers including aluminum, or indium, or both. Material layers of a compound semiconductor alloy such as AlGaInP or the like may be anisotropically etched for forming electronic devices including field-effect transistors and heterojunction bipolar transistors and for forming photonic devices including vertical-cavity surface-emitting lasers, edge-emitting lasers, and reflectance modulators.

  4. Method of physical vapor deposition of metal oxides on semiconductors

    DOE Patents [OSTI]

    Norton, David P. (Knoxville, TN)

    2001-01-01T23:59:59.000Z

    A process for growing a metal oxide thin film upon a semiconductor surface with a physical vapor deposition technique in a high-vacuum environment and a structure formed with the process involves the steps of heating the semiconductor surface and introducing hydrogen gas into the high-vacuum environment to develop conditions at the semiconductor surface which are favorable for growing the desired metal oxide upon the semiconductor surface yet is unfavorable for the formation of any native oxides upon the semiconductor. More specifically, the temperature of the semiconductor surface and the ratio of hydrogen partial pressure to water pressure within the vacuum environment are high enough to render the formation of native oxides on the semiconductor surface thermodynamically unstable yet are not so high that the formation of the desired metal oxide on the semiconductor surface is thermodynamically unstable. Having established these conditions, constituent atoms of the metal oxide to be deposited upon the semiconductor surface are directed toward the surface of the semiconductor by a physical vapor deposition technique so that the atoms come to rest upon the semiconductor surface as a thin film of metal oxide with no native oxide at the semiconductor surface/thin film interface. An example of a structure formed by this method includes an epitaxial thin film of (001)-oriented CeO.sub.2 overlying a substrate of (001) Ge.

  5. Semiconductor liquid crystal composition and methods for making the same

    DOE Patents [OSTI]

    Alivisatos, A. Paul; Li, Liang-shi

    2005-04-26T23:59:59.000Z

    Semiconductor liquid crystal compositions and methods for making such compositions are disclosed. One embodiment of the invention is directed to a liquid crystal composition including a solvent and semiconductor particles in the solvent. The solvent and the semiconductor particles are in an effective amount in the liquid crystal composition to form a liquid crystal phase.

  6. Quantum of optical absorption in two-dimensional semiconductors

    E-Print Network [OSTI]

    California at Irvine, University of

    Quantum of optical absorption in two-dimensional semiconductors Hui Fanga,b,c , Hans A. Bechteld semiconductor, where is the fine structure con- stant and nc is an optical local field correction factor quantitative examination of the intrinsic absorption properties of free-standing 2D semiconductor thin films

  7. Effects of Quantum Confinement on the Doping Limit of Semiconductor

    E-Print Network [OSTI]

    Wu, Junqiao

    Effects of Quantum Confinement on the Doping Limit of Semiconductor Nanowires D. R. Khanal,, Joanne concentrations in semiconductor nanowires. Our calculations are based on the amphoteric defect model, which describes the thermodynamic doping limit in semiconductors in terms of the compensation of external dopants

  8. Defects activated photoluminescence in two-dimensional semiconductors

    E-Print Network [OSTI]

    Wu, Junqiao

    Defects activated photoluminescence in two-dimensional semiconductors: interplay between bound of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, People's Republic of China, 3, Berkeley, California 94720, United States. Point defects in semiconductors can trap free charge carriers

  9. Structure and magnetism of transition-metal implanted dilute magnetic semiconductors

    E-Print Network [OSTI]

    Pereira, Lino; Temst, K; Araújo, JP; Wahl, U

    The discovery of a dilute magnetic semiconductor (DMS) in which ferromagnetism is carrier-mediated and persists above room temperature is a critical step towards the development of semiconductor-based spintronics. Among the many types of DMS materials which have been investigated, the current research interest can be narrowed down to two main classes of materials: (1) narrow-gap III-V semiconductors, mostly GaAs and InAs, doped with Mn; (2) wide-gap oxides and nitrides doped with 3d transition metals, mostly Mn- and Co-doped ZnO and Mn-doped GaN. With a number of interesting functionalities deriving from the carrier-mediated ferromagnetism and demonstrated in various proof-of-concept devices, Mn-doped GaAs has become, among DMS materials, one of the best candidates for technological application. However, despite major developments over the last 15 years, the maximum Curie temperature (185 K) remains well below room temperature. On the other hand, wide-gap DMS materials appear to exhibit ferromagnetic behavior...

  10. 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.

  11. Analog Sauter-Schwinger effect in semiconductors

    E-Print Network [OSTI]

    Linder, Malte F

    2015-01-01T23:59:59.000Z

    We develop a 1+1-dimensional model of a semiconductor, which exhibits an analog of the nonperturbative electron-positron pair creation from the quantum vacuum via time-dependent external electric fields (Sauter-Schwinger effect). In the one-particle picture of the relativistic Dirac theory, pair production from the Dirac vacuum can be understood as the excitation of a Dirac sea electron into the upper energy continuum. The analog effect in the semiconductor model is the excitation of electrons from the valence band into the conduction band (electron-hole pair creation). We show that the underlying equations describing the excitation processes in both systems are in some cases formally equivalent. The critical electric field strength for the Sauter-Schwinger effect is much smaller in typical semiconductors than in Dirac theory due to the different physical scales. This fact makes analog systems like the semiconductor model promising candidates for the observation of the Sauter-Schwinger effect in the laborator...

  12. High resolution scintillation detector with semiconductor readout

    DOE Patents [OSTI]

    Levin, Craig S. (Santa Monica, CA); Hoffman, Edward J. (Los Angeles, CA)

    2000-01-01T23:59:59.000Z

    A novel high resolution scintillation detector array for use in radiation imaging such as high resolution Positron Emission Tomography (PET) which comprises one or more parallelepiped crystals with at least one long surface of each crystal being in intimate contact with a semiconductor photodetector such that photons generated within each crystal by gamma radiation passing therethrough is detected by the photodetector paired therewith.

  13. HYDROGEN LOCAL VIBRATIONAL MODES IN COMPOUND SEMICONDUCTORS

    E-Print Network [OSTI]

    McCluskey, Matthew

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

  14. Organic conductive films for semiconductor electrodes

    DOE Patents [OSTI]

    Frank, A.J.

    1984-01-01T23:59:59.000Z

    According to the present invention, improved electrodes overcoated with conductive polymer films and preselected catalysts are provided. The electrodes typically comprise an inorganic semiconductor over-coated with a charge conductive polymer film comprising a charge conductive polymer in or on which is a catalyst or charge-relaying agent.

  15. Optical temperature sensor using thermochromic semiconductors

    DOE Patents [OSTI]

    Kronberg, J.W.

    1994-01-01T23:59:59.000Z

    Optical thermometry is a growing technological field which exploits the ability of certain materials to change their optical properties with temperature. A subclass of such materials are those which change their color as a reversible and reproducible function of temperature. These materials are thermochromic. This invention is a composition to measure temperature utilizing thermochromic semiconductors.

  16. Laterally coupled-cavity semiconductor lasers

    SciTech Connect (OSTI)

    Lang, R.J.; Yariv, A.; Salzman, J.

    1987-04-01T23:59:59.000Z

    The authors analyze the threshold behaviour or a pair of laterally coupled semiconductor lasers of different lengths. The predictions include longitudinal mode selectivity leading to single longitudinal mode operation with a periodicity determined by the length mismatch, and ripples in the equipower curves in the current plane due to carrier-induced index shifts. They present experimental measurements that confirm these predictions.

  17. Theory of longitudinal modes in semiconductor lasers

    SciTech Connect (OSTI)

    Lau, K.Y.; Yariv, A.

    1982-05-01T23:59:59.000Z

    A theory of longitudinal mode lasing spectrum of semiconductor lasers is developed which takes into account the nonuniform carrier and photon distributions and local gain spectrum shifts inside lasers with low end mirror reflectivities. The theory gives results consistent with observed longitudinal mode behavior in lasers with reduced facet reflectivity.

  18. Semiconductor Nanowire Optical Antenna Solar Absorbers

    E-Print Network [OSTI]

    Fan, Shanhui

    a clear, intuitive guidance for the design of efficient NW solar cells. The presented approach technology. KEYWORDS Solar cell, semiconductor nanowires, optical antennas, photon management, light trapping employing non-earth-abundant elements like indium (CuInGaSe or CIGS cells) or tellurium (CdTe cells

  19. Preparation of III-V semiconductor nanocrystals

    DOE Patents [OSTI]

    Alivisatos, A.P.; Olshavsky, M.A.

    1996-04-09T23:59:59.000Z

    Nanometer-scale crystals of III-V semiconductors are disclosed. They are prepared by reacting a group III metal source with a group V anion source in a liquid phase at elevated temperature in the presence of a crystallite growth terminator such as pyridine or quinoline. 4 figs.

  20. Semiconductor laser with multiple lasing wavelengths

    DOE Patents [OSTI]

    Fischer, Arthur J.; Choquette, Kent D.; Chow, Weng W.

    2003-07-29T23:59:59.000Z

    A new class of multi-terminal vertical-cavity semiconductor laser components has been developed. These multi-terminal laser components can be switched, either electrically or optically, between distinct lasing wavelengths, or can be made to lase simultaneously at multiple wavelengths.

  1. Optimal Preventive Maintenance Scheduling in Semiconductor Manufacturing

    E-Print Network [OSTI]

    Marcus, Steven I.

    1 Optimal Preventive Maintenance Scheduling in Semiconductor Manufacturing Xiaodong Yao, Emmanuel on Control Applications in 2001. #12;2 Abstract Preventive Maintenance (PM) scheduling is a very challenging schedule with that of a baseline reference schedule are also presented. Index Terms preventive maintenance

  2. Semiconductor detectors with proximity signal readout

    SciTech Connect (OSTI)

    Asztalos, Stephen J. [XIA, LLC, Hayward, CA (United States)

    2014-01-30T23:59:59.000Z

    Semiconductor-based radiation detectors are routinely used for the detection, imaging, and spectroscopy of x-rays, gamma rays, and charged particles for applications in the areas of nuclear and medical physics, astrophysics, environmental remediation, nuclear nonproliferation, and homeland security. Detectors used for imaging and particle tracking are more complex in that they typically must also measure the location of the radiation interaction in addition to the deposited energy. In such detectors, the position measurement is often achieved by dividing or segmenting the electrodes into many strips or pixels and then reading out the signals from all of the electrode segments. Fine electrode segmentation is problematic for many of the standard semiconductor detector technologies. Clearly there is a need for a semiconductor-based radiation detector technology that can achieve fine position resolution while maintaining the excellent energy resolution intrinsic to semiconductor detectors, can be fabricated through simple processes, does not require complex electrical interconnections to the detector, and can reduce the number of required channels of readout electronics. Proximity electrode signal readout (PESR), in which the electrodes are not in physical contact with the detector surface, satisfies this need.

  3. Solid State Lighting Semiconductor Spectroscopy & Devices

    E-Print Network [OSTI]

    Strathclyde, University of

    and fluorescent lamps, are very inefficient in transforming energy into light. Due to upcoming problems in energy % of Earth's total power consumption is used for lighting! Figure 3: Earth at night from space. Evolution inside a semiconductor for light emission. Over 150 years ago... How to achieve white LEDs? Figure 5

  4. Preparation of III-V semiconductor nanocrystals

    DOE Patents [OSTI]

    Alivisatos, A. Paul (Berkeley, CA); Olshavsky, Michael A. (Brunswick, OH)

    1996-01-01T23:59:59.000Z

    Nanometer-scale crystals of III-V semiconductors are disclosed, They are prepared by reacting a group III metal source with a group V anion source in a liquid phase at elevated temperature in the presence of a crystallite growth terminator such as pyridine or quinoline.

  5. Analog Sauter-Schwinger effect in semiconductors

    E-Print Network [OSTI]

    Malte F. Linder; Ralf Schützhold

    2015-03-24T23:59:59.000Z

    We develop a 1+1-dimensional model of a semiconductor, which exhibits an analog of the nonperturbative electron-positron pair creation from the quantum vacuum via time-dependent external electric fields (Sauter-Schwinger effect). In the one-particle picture of the relativistic Dirac theory, pair production from the Dirac vacuum can be understood as the excitation of a Dirac sea electron into the upper energy continuum. The analog effect in the semiconductor model is the excitation of electrons from the valence band into the conduction band (electron-hole pair creation). We show that the underlying equations describing the excitation processes in both systems are in some cases formally equivalent. The critical electric field strength for the Sauter-Schwinger effect is much smaller in typical semiconductors than in Dirac theory due to the different physical scales. This fact makes analog systems like the semiconductor model promising candidates for the observation of the Sauter-Schwinger effect in the laboratory.

  6. Bi-Se doped with Cu, p-type semiconductor

    DOE Patents [OSTI]

    Bhattacharya, Raghu Nath; Phok, Sovannary; Parilla, Philip Anthony

    2013-08-20T23:59:59.000Z

    A Bi--Se doped with Cu, p-type semiconductor, preferably used as an absorber material in a photovoltaic device. Preferably the semiconductor has at least 20 molar percent Cu. In a preferred embodiment, the semiconductor comprises at least 28 molar percent of Cu. In one embodiment, the semiconductor comprises a molar percentage of Cu and Bi whereby the molar percentage of Cu divided by the molar percentage of Bi is greater than 1.2. In a preferred embodiment, the semiconductor is manufactured as a thin film having a thickness less than 600 nm.

  7. Wide field of view telescope

    DOE Patents [OSTI]

    Ackermann, Mark R. (Albuquerque, NM); McGraw, John T. (Placitas, NM); Zimmer, Peter C. (Albuquerque, NM)

    2008-01-15T23:59:59.000Z

    A wide field of view telescope having two concave and two convex reflective surfaces, each with an aspheric surface contour, has a flat focal plane array. Each of the primary, secondary, tertiary, and quaternary reflective surfaces are rotationally symmetric about the optical axis. The combination of the reflective surfaces results in a wide field of view in the range of approximately 3.8.degree. to approximately 6.5.degree.. The length of the telescope along the optical axis is approximately equal to or less than the diameter of the largest of the reflective surfaces.

  8. SOFTWAREENGINEERING The World Wide Web

    E-Print Network [OSTI]

    Whitehead, James

    SOFTWAREENGINEERING The World Wide Web Distributed Authoring and Versioning working group on the Web. WEBDAV: IETF Standard for Collaborative Authoring on the Web E. JAMES WHITEHEAD, JR. University remains to be done. What if instead you could simply edit Web documents (or any Web resource) in place

  9. Going Deep vs. Going Wide

    Broader source: Energy.gov [DOE]

    Going Deep vs. Going Wide, from the Residential Energy Efficiency Solutions Conference 2012. Provides an overview on the progress of four energy efficiency programs: Clean Energy Works Oregon, Efficiency Maine, Energy Upgrade California Flex Path, and EcoHouse Loan Program.

  10. Time-resolved THz studies of carrier dynamics in semiconductors, superconductors, and strongly-correlated electron materials

    E-Print Network [OSTI]

    Kaindl, Robert A

    2011-01-01T23:59:59.000Z

    correlation effects in semiconductors, Nature 411, 549-557,in optically excited semiconductors, Phys. Rev. B 54,and Terahertz Gain in Semiconductors Excited to Resonance,

  11. Proximity charge sensing for semiconductor detectors

    DOE Patents [OSTI]

    Luke, Paul N; Tindall, Craig S; Amman, Mark

    2013-10-08T23:59:59.000Z

    A non-contact charge sensor includes a semiconductor detector having a first surface and an opposing second surface. The detector includes a high resistivity electrode layer on the first surface and a low resistivity electrode on the high resistivity electrode layer. A portion of the low resistivity first surface electrode is deleted to expose the high resistivity electrode layer in a portion of the area. A low resistivity electrode layer is disposed on the second surface of the semiconductor detector. A voltage applied between the first surface low resistivity electrode and the second surface low resistivity electrode causes a free charge to drift toward the first or second surface according to a polarity of the free charge and the voltage. A charge sensitive preamplifier coupled to a non-contact electrode disposed at a distance from the exposed high resistivity electrode layer outputs a signal in response to movement of free charge within the detector.

  12. Semiconductor Probes of Light Dark Matter

    E-Print Network [OSTI]

    Peter W. Graham; David E. Kaplan; Surjeet Rajendran; Matthew T. Walters

    2012-11-12T23:59:59.000Z

    Dark matter with mass below about a GeV is essentially unobservable in conventional direct detection experiments. However, newly proposed technology will allow the detection of single electron events in semiconductor materials with significantly lowered thresholds. This would allow detection of dark matter as light as an MeV in mass. Compared to other detection technologies, semiconductors allow enhanced sensitivity because of their low ionization energy around an eV. Such detectors would be particularly sensitive to dark matter with electric and magnetic dipole moments, with a reach many orders of magnitude beyond current bounds. Observable dipole moment interactions can be generated by new particles with masses as great as 1000 TeV, providing a window to scales beyond the reach of current colliders.

  13. Optical cavity furnace for semiconductor wafer processing

    DOE Patents [OSTI]

    Sopori, Bhushan L.

    2014-08-05T23:59:59.000Z

    An optical cavity furnace 10 having multiple optical energy sources 12 associated with an optical cavity 18 of the furnace. The multiple optical energy sources 12 may be lamps or other devices suitable for producing an appropriate level of optical energy. The optical cavity furnace 10 may also include one or more reflectors 14 and one or more walls 16 associated with the optical energy sources 12 such that the reflectors 14 and walls 16 define the optical cavity 18. The walls 16 may have any desired configuration or shape to enhance operation of the furnace as an optical cavity 18. The optical energy sources 12 may be positioned at any location with respect to the reflectors 14 and walls defining the optical cavity. The optical cavity furnace 10 may further include a semiconductor wafer transport system 22 for transporting one or more semiconductor wafers 20 through the optical cavity.

  14. GaTe semiconductor for radiation detection

    DOE Patents [OSTI]

    Payne, Stephen A. (Castro Valley, CA); Burger, Arnold (Nashville, TN); Mandal, Krishna C. (Ashland, MA)

    2009-06-23T23:59:59.000Z

    GaTe semiconductor is used as a room-temperature radiation detector. GaTe has useful properties for radiation detectors: ideal bandgap, favorable mobilities, low melting point (no evaporation), non-hygroscopic nature, and availability of high-purity starting materials. The detector can be used, e.g., for detection of illicit nuclear weapons and radiological dispersed devices at ports of entry, in cities, and off shore and for determination of medical isotopes present in a patient.

  15. Scanning probe microscopy studies of semiconductor surfaces

    SciTech Connect (OSTI)

    Weinberg, W.H. [Univ. of California, Santa Barbara, CA (United States)

    1996-10-01T23:59:59.000Z

    Recent work involving atomic force microscopy and scanning tunneling microscopy is discussed which involves strain-induced, self-assembling nanostructures in compound semiconductor materials. Specific examples include one-dimensional quantum wires of InAs grown by MBE on GaAs(001) and zero-dimensional quantum dots of InP grown by MOCVD on InGaP which is lattice matched to GaAs(001).

  16. Visible-wavelength semiconductor lasers and arrays

    DOE Patents [OSTI]

    Schneider, Jr., Richard P. (Albuquerque, NM); Crawford, Mary H. (Albuquerque, NM)

    1996-01-01T23:59:59.000Z

    A visible semiconductor laser. The visible semiconductor laser includes an InAlGaP active region surrounded by one or more AlGaAs layers on each side, with carbon as the sole p-type dopant. Embodiments of the invention are provided as vertical-cavity surface-emitting lasers (VCSELs) and as edge-emitting lasers (EELs). One or more transition layers comprised of a substantially indium-free semiconductor alloy such as AlAsP, AlGaAsP, or the like may be provided between the InAlGaP active region and the AlGaAS DBR mirrors or confinement layers to improve carrier injection and device efficiency by reducing any band offsets. Visible VCSEL devices fabricated according to the invention with a one-wavelength-thick (1.lambda.) optical cavity operate continuous-wave (cw) with lasing output powers up to 8 mW, and a peak power conversion efficiency of up to 11%.

  17. 7/14/2004 World of Compound Semiconductors Page 1 of 191 TThhee WWoorrlldd

    E-Print Network [OSTI]

    7/14/2004 World of Compound Semiconductors Page 1 of 191 TThhee WWoorrlldd ooff CCoommppoouunndd ...... ---- ...... ---- ...... ---- ...... ---- ...... ---- ...... ---- ...... ---- #12;7/14/2004 World of Compound Semiconductors Page 2 of 191 0.1 Scope Compound III-V Semiconductors A new family of semiconductors is changing the way we live. These semiconductors are in our cell phones

  18. 1.0. Semiconductor Diodes 1 of 27 1.2 Ideal Diode

    E-Print Network [OSTI]

    Allen, Gale

    1.0. Semiconductor Diodes 1 of 27 1.2 Ideal Diode ID VD ID Open Circuit Short Circuit VD + - #12;1.0. Semiconductor Diodes 2 of 27 1.3 Semiconductor Materials Conductor Insulator Semiconductor R = (Resistivity Resistivity of a semiconductor decreases as temperature increases. ure coefficient.Negative temperat #12

  19. Photovoltaic healing of non-uniformities in semiconductor devices

    DOE Patents [OSTI]

    Karpov, Victor G.; Roussillon, Yann; Shvydka, Diana; Compaan, Alvin D.; Giolando, Dean M.

    2006-08-29T23:59:59.000Z

    A method of making a photovoltaic device using light energy and a solution to normalize electric potential variations in the device. A semiconductor layer having nonuniformities comprising areas of aberrant electric potential deviating from the electric potential of the top surface of the semiconductor is deposited onto a substrate layer. A solution containing an electrolyte, at least one bonding material, and positive and negative ions is applied over the top surface of the semiconductor. Light energy is applied to generate photovoltage in the semiconductor, causing a redistribution of the ions and the bonding material to the areas of aberrant electric potential. The bonding material selectively bonds to the nonuniformities in a manner such that the electric potential of the nonuniformities is normalized relative to the electric potential of the top surface of the semiconductor layer. A conductive electrode layer is then deposited over the top surface of the semiconductor layer.

  20. Method and system for powering and cooling semiconductor lasers

    DOE Patents [OSTI]

    Telford, Steven J; Ladran, Anthony S

    2014-02-25T23:59:59.000Z

    A semiconductor laser system includes a diode laser tile. The diode laser tile includes a mounting fixture having a first side and a second side opposing the first side and an array of semiconductor laser pumps coupled to the first side of the mounting fixture. The semiconductor laser system also includes an electrical pulse generator thermally coupled to the diode bar and a cooling member thermally coupled to the diode bar and the electrical pulse generator.

  1. Graded core/shell semiconductor nanorods and nanorod barcodes

    DOE Patents [OSTI]

    Alivisatos, A. Paul; Scher, Erik C.; Manna, Liberato

    2013-03-26T23:59:59.000Z

    Graded core/shell semiconductor nanorods and shapped nanorods are disclosed comprising Group II-VI, Group III-V and Group IV semiconductors and methods of making the same. Also disclosed are nanorod barcodes using core/shell nanorods where the core is a semiconductor or metal material, and with or without a shell. Methods of labeling analytes using the nanorod barcodes are also disclosed.

  2. Graded core/shell semiconductor nanorods and nanorod barcodes

    DOE Patents [OSTI]

    Alivisatos, A. Paul (Oakland, CA); Scher, Erik C. (San Francisco, CA); Manna, Liberato (Palo Del Collie, IT)

    2009-05-19T23:59:59.000Z

    Disclosed herein is a graded core/shell semiconductor nanorod having at least a first segment of a core of a Group II-VI, Group III-V or a Group IV semiconductor, a graded shell overlying the core, wherein the graded shell comprises at least two monolayers, wherein the at least two monolayers each independently comprise a Group II-VI, Group III-V or a Group IV semiconductor.

  3. Graded core/shell semiconductor nanorods and nanorod barcodes

    DOE Patents [OSTI]

    Alivisatos, A. Paul (Oakland, CA); Scher, Erik C. (San Francisco, CA); Manna, Liberato (Lecce, IT)

    2010-12-14T23:59:59.000Z

    Graded core/shell semiconductor nanorods and shaped nanorods are disclosed comprising Group II-VI, Group III-V and Group IV semiconductors and methods of making the same. Also disclosed are nanorod barcodes using core/shell nanorods where the core is a semiconductor or metal material, and with or without a shell. Methods of labeling analytes using the nanorod barcodes are also disclosed.

  4. Deposition method for producing silicon carbide high-temperature semiconductors

    DOE Patents [OSTI]

    Hsu, George C. (La Crescenta, CA); Rohatgi, Naresh K. (W. Corine, CA)

    1987-01-01T23:59:59.000Z

    An improved deposition method for producing silicon carbide high-temperature semiconductor material comprising placing a semiconductor substrate composed of silicon carbide in a fluidized bed silicon carbide deposition reactor, fluidizing the bed particles by hydrogen gas in a mildly bubbling mode through a gas distributor and heating the substrate at temperatures around 1200.degree.-1500.degree. C. thereby depositing a layer of silicon carbide on the semiconductor substrate.

  5. Production of pulsed, mass-selected beams of metal and semiconductor clusters

    SciTech Connect (OSTI)

    Kamalou, Omar; Rangama, Jimmy; Ramillon, Jean-Marc; Guinement, Patrick; Huber, Bernd A. [CIMAP, CEA-CNRS-ENSICaen-UCBN, Bv. Henry Becquerel (B.P. 5133), F-14070 Caen Cedex 05 (France)

    2008-06-15T23:59:59.000Z

    We report on the development of a beam line for mass-selected metal and semiconductor clusters. The cluster source combines the principles of plasma sputtering and gas condensation. Both techniques together allow to produce clusters in a wide size range. With the aid of a time-of-flight system, small clusters (i.e., Cu{sub n}{sup +}, n<100) are selected and pure beams containing only one cluster size are provided. For large clusters (containing several thousands of atoms), a beam with a narrow size distribution is obtained. A 90 deg. quadrupole deviator is used to separate charged clusters from neutral ones.

  6. Method for fabricating an interconnected array of 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)

    1989-10-10T23:59:59.000Z

    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.

  7. Kyungdong Photovoltaic Energy Corp KPE formerly Photon Semiconductor...

    Open Energy Info (EERE)

    Kyungdong Photovoltaic Energy Corp KPE formerly Photon Semiconductor Energy Jump to: navigation, search Name: Kyungdong Photovoltaic Energy Corp (KPE) (formerly Photon...

  8. Magnetic Gas Sensing Using a Dilute Magnetic Semiconductor. ...

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

    Abstract: The authors report on a magnetic gas sensing methodology to detect hydrogen using the ferromagnetic properties of a nanoscale dilute magnetic semiconductor...

  9. Method for depositing high-quality microcrystalline semiconductor materials

    DOE Patents [OSTI]

    Guha, Subhendu (Bloomfield Hills, MI); Yang, Chi C. (Troy, MI); Yan, Baojie (Rochester Hills, MI)

    2011-03-08T23:59:59.000Z

    A process for the plasma deposition of a layer of a microcrystalline semiconductor material is carried out by energizing a process gas which includes a precursor of the semiconductor material and a diluent with electromagnetic energy so as to create a plasma therefrom. The plasma deposits a layer of the microcrystalline semiconductor material onto the substrate. The concentration of the diluent in the process gas is varied as a function of the thickness of the layer of microcrystalline semiconductor material which has been deposited. Also disclosed is the use of the process for the preparation of an N-I-P type photovoltaic device.

  10. Statistical Methods for Enhanced Metrology in Semiconductor/Photovoltaic Manufacturing

    E-Print Network [OSTI]

    Zeng, Dekong

    2012-01-01T23:59:59.000Z

    process control charts (SPC) for product quality and processstatistical process control (SPC) charts. The concept is toMethods Univariate SPC for semiconductor manufacturing

  11. Argonne announces new licensing agreement with AKHAN Semiconductor...

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

    Argonne announces new licensing agreement with AKHAN Semiconductor By Jared Sagoff * November 19, 2014 Tweet EmailPrint ARGONNE, Ill. - The U.S. Department of Energy's (DOE)...

  12. Exploring Electron Transfer in Organic Semiconductors | MIT-Harvard...

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

    Electron Transfer in Organic Semiconductors January 28, 2009 at 3pm36-428 Troy Van Voorhis Department of Chemistry, Massachusetts Institute of Technology vanvoorhis2000 abstract:...

  13. Metal Oxide Semiconductor Nanoparticles Open the Door to New...

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

    Innovations Technology available for licensing: novel nanometer-sized metal oxide semiconductors that allow targeting, initiating and control of in vitro and in vivo chemical...

  14. Ferromagnetic Semiconductor Nanoclusters: Co-doped Cu2O. | EMSL

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

    exhibits a temperature dependent decrease. Citation: Antony J, Y Qiang, F Muhammad, D Meyer, DE McCready, and MH Engelhard.2007."Ferromagnetic Semiconductor Nanoclusters:...

  15. The Technical and Economic Potential for Electricity Energy Efficiency in a Semiconductor Manufacturing Plant

    E-Print Network [OSTI]

    Lee, A. H. W.; Golden, J. W.; Zarnikau, J. W.

    In recent years, there has been renewed interest in energy efficiency in the semiconductor industry. The declining prices for semiconductor products has prompted semiconductor manufacturing plants to control costs so as to maintain profitability...

  16. Polarized x-ray spectroscopy of quaternary ferromagnetic semiconductor (Ga,Mn)(As,P)

    E-Print Network [OSTI]

    Wadley, P.

    2011-01-01T23:59:59.000Z

    quaternary diluted magnetic semiconductor (Ga,Mn)(As,P) as aIn diluted magnetic semiconductors such as (Ga,Mn)As, whichquaternary diluted magnetic semiconductors such as (Ga,Mn)(

  17. Construction of a Deep Level Transient Spectroscopy (DLTS) Setup Semiconductors and DLTS

    E-Print Network [OSTI]

    Zhao, Yuxiao

    Construction of a Deep Level Transient Spectroscopy (DLTS) Setup Semiconductors and DLTS Semiconductor devices are central to information technology. Their importance stems from the fact Ian Booker Semiconductor Materials Group Dept. Of Physics, Chemistry and Biology, IFM Linköping

  18. Study of Semiconductor Microring Lasers for use in Wavelength Division Multiplexing (WDM)

    E-Print Network [OSTI]

    Kouroupetroglou, Georgios

    Study of Semiconductor Microring Lasers for use in Wavelength Division Multiplexing (WDM of all-active microring resonators as lasers are studied. The structure of a semiconductor microring demonstrated. Keywords: Semiconductor microring lasers, non-linear gain, multimode operation, mode

  19. Atomic and electronic structures of oxides on III-V semiconductors :

    E-Print Network [OSTI]

    Shen, Jian

    2010-01-01T23:59:59.000Z

    and passivation of a compound semiconductor surface duringIn 2 O and SiO/III-V Semiconductor Interface, in press with2 O and SiO/III-V Semiconductor Interface, ECS Transaction (

  20. Strain broadening of the magnetization steps in diluted magnetic semiconductors Yuri G. Rubo* and M. F. Thorpe

    E-Print Network [OSTI]

    Thorpe, Michael

    Strain broadening of the magnetization steps in diluted magnetic semiconductors Yuri G. Rubo* and M alloys diluted magnetic semiconductors results in fluctuations of the exchange constants between semiconducting alloys, the so- called semimagnetic semiconductors or diluted magnetic semiconductors DMS

  1. Visible-light photoconductivity of Zn1-xCoxO and its dependence...

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

    on Co2+ concentration. Abstract: Many metal oxides investigated for solar photocatalysis or photoelectrochemistry have band gaps that are too wide to absorb a sufficient...

  2. Wide-range voltage modulation

    SciTech Connect (OSTI)

    Rust, K.R.; Wilson, J.M.

    1992-06-01T23:59:59.000Z

    The Superconducting Super Collider`s Medium Energy Booster Abort (MEBA) kicker modulator will supply a current pulse to the abort magnets which deflect the proton beam from the MEB ring into a designated beam stop. The abort kicker will be used extensively during testing of the Low Energy Booster (LEB) and the MEB rings. When the Collider is in full operation, the MEBA kicker modulator will abort the MEB beam in the event of a malfunction during the filling process. The modulator must generate a 14-{mu}s wide pulse with a rise time of less than 1 {mu}s, including the delay and jitter times. It must also be able to deliver a current pulse to the magnet proportional to the beam energy at any time during ramp-up of the accelerator. Tracking the beam energy, which increases from 12 GeV at injection to 200 GeV at extraction, requires the modulator to operate over a wide range of voltages (4 kV to 80 kV). A vacuum spark gap and a thyratron have been chosen for test and evaluation as candidate switches for the abort modulator. Modulator design, switching time delay, jitter and pre-fire data are presented.

  3. Semiconductor heterojunction band offsets and charge neutrality

    E-Print Network [OSTI]

    Lee, Chomsik

    1989-01-01T23:59:59.000Z

    = 33&Pb = 3 3&PAB = 35 1 . aI M 0 A 0. ? 1 2. 0. Energy(eV) 1 2. 0 0. ? 1 0. Energy(eV) 1 2. Figure 4. 4. Local density of states, parameters for this case are s, = ? 7, s?= 1, s, = l&sp 7~Pa = 4~A = 4)DAB ? .35. -12. 0. Energy(eV) 0... Signature of APS Member Roland E. Allen Department of Physics'- Texas A&M University ' College Station, TX 77843 s p ~ CX3 SEMICONDUCTOR HETEROJUNCTION BAND OFFSETS AND CHARGE NEUTRALITY A Thesis by CHOMSIK LEE Submitted to the Oflice of Graduate...

  4. Transient Rayleigh scattering from single semiconductor nanowires

    SciTech Connect (OSTI)

    Montazeri, Mohammad; Jackson, Howard E.; Smith, Leigh M. [Department of Physics, University of Cincinnati, Cincinnati, OH 45221-0011 (United States); Yarrison-Rice, Jan M. [Department of Physics, Miami University, Oxford, OH 45056 (United States); Kang, Jung-Hyun; Gao, Qiang; Tan, Hark Hoe; Jagadish, Chennupati [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia)

    2013-12-04T23:59:59.000Z

    Transient Rayleigh scattering spectroscopy is a new pump-probe technique to study the dynamics and cooling of photo-excited carriers in single semiconductor nanowires. By studying the evolution of the transient Rayleigh spectrum in time after excitation, one can measure the time evolution of the density and temperature of photo-excited electron-hole plasma (EHP) as they equilibrate with lattice. This provides detailed information of dynamics and cooling of carriers including linear and bimolecular recombination properties, carrier transport characteristics, and the energy-loss rate of hot electron-hole plasma through the emission of LO and acoustic phonons.

  5. GaAs photoconductive semiconductor switch

    DOE Patents [OSTI]

    Loubriel, G.M.; Baca, A.G.; Zutavern, F.J.

    1998-09-08T23:59:59.000Z

    A high gain, optically triggered, photoconductive semiconductor switch (PCSS) implemented in GaAs as a reverse-biased pin structure with a passivation layer above the intrinsic GaAs substrate in the gap between the two electrodes of the device is disclosed. The reverse-biased configuration in combination with the addition of the passivation layer greatly reduces surface current leakage that has been a problem for prior PCSS devices and enables employment of the much less expensive and more reliable DC charging systems instead of the pulsed charging systems that needed to be used with prior PCSS devices. 5 figs.

  6. GaAs photoconductive semiconductor switch

    DOE Patents [OSTI]

    Loubriel, Guillermo M. (Sandia Park, NM); Baca, Albert G. (Albuquerque, NM); Zutavern, Fred J. (Albuquerque, NM)

    1998-01-01T23:59:59.000Z

    A high gain, optically triggered, photoconductive semiconductor switch (PCSS) implemented in GaAs as a reverse-biased pin structure with a passivation layer above the intrinsic GaAs substrate in the gap between the two electrodes of the device. The reverse-biased configuration in combination with the addition of the passivation layer greatly reduces surface current leakage that has been a problem for prior PCSS devices and enables employment of the much less expensive and more reliable DC charging systems instead of the pulsed charging systems that needed to be used with prior PCSS devices.

  7. Dissipative dynamics in semiconductors at low temperature

    E-Print Network [OSTI]

    George Androulakis; Jean Bellissard; Christian Sadel

    2011-07-06T23:59:59.000Z

    A mathematical model is introduced which describes the dissipation of electrons in lightly doped semi-conductors. The dissipation operator is proved to be densely defined and positive and to generate a Markov semigroup of operators. The spectrum of the dissipation operator is studied and it is shown that zero is a simple eigenvalue, which makes the equilibrium state unique. Also it is shown that there is a gap between zero and the rest of its spectrum which makes the return to equilibrium exponentially fast in time.

  8. Modular Algorithms for Transient Semiconductor Device Simulation, Part I

    E-Print Network [OSTI]

    Jerome, Joseph W.

    Modular Algorithms for Transient Semiconductor Device Simulation, Part I: Analysis of the Outer, is introduced at dis- crete time steps for the one-dimensional semiconductor device model. The it- eration as approximate Newton iterations. Continuation is employed as the time-stepping bridge. 1 Introduction In Part I

  9. Effect of superluminescence on the modulation response of semiconductor lasers

    SciTech Connect (OSTI)

    Lau, K.Y.; Yariv, A.

    1982-03-15T23:59:59.000Z

    The small-signal modulation response of semiconductor lasers with a very small mirror reflectivity is analyzed. Superluminescent effects inside the laser cavity provide yet another mechanism for damping relaxation oscillation resonance. These results can serve as useful guides in designing high frequency semiconductor lasers.

  10. Profiling the Thermoelectric Power of Semiconductor Junctions with

    E-Print Network [OSTI]

    Profiling the Thermoelectric Power of Semiconductor Junctions with Nanometer Resolution Ho-Ki Lyeo,3 * We have probed the local thermoelectric power of semiconductor nanostruc- tures with the use of ultrahigh-vacuum scanning thermoelectric microscopy. When applied to a p-n junction, this method reveals

  11. ECE 451 -Fall 2011 Physics of Semiconductor Devices (3)

    E-Print Network [OSTI]

    Gilchrist, James F.

    ECE 451 - Fall 2011 Physics of Semiconductor Devices (3) Electronics and Optoelectronics-Photon Scattering Processes (Optional) 18. Novel Optoelectronics and Electronics Devices (Optional) Structure on Semiconductor Physics and Device Physics, Draft Version (2010). Other Additional References or Readings: 1. J

  12. hal00267005, Modeling semiconductor thermal properties. The dispersion role.

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    , or in solar panels 3 , and are even used in medicine 4 . The increasing use of semiconductor micro in transistors 6 and semiconductor nano#12;lms in solar cells. At these low scale, Fourier's law may give , similar to photon intensity used in radiative transfer 24 . Thus, the energy ux per apparent surface unit

  13. Propagation of Nonclassical Radiation through a Semiconductor Slab

    E-Print Network [OSTI]

    D. Yu. Vasylyev; W. Vogel; T. Schmielau; K. Henneberger; D. -G. Welsch

    2008-02-20T23:59:59.000Z

    Based on a microscopic derivation of the emission spectra of a bulk semiconductor we arrive at a clear physical interpretation of the noise current operators in macroscopic quantum electrodynamics. This opens the possibility to study medium effects on nonclassical radiation propagating through an absorbing or amplifying semiconductor. As an example, the propagation of an incident squeezed vacuum is analyzed.

  14. Semiconductor Nanocomposites DOI: 10.1002/anie.201100200

    E-Print Network [OSTI]

    Lin, Zhiqun

    Semiconductor Nanocomposites DOI: 10.1002/anie.201100200 Semiconductor Anisotropic Nanocomposites-based organic/inorganic hybrid solar cells (e.g., CP/QD composites) are favorable alternatives to inorganic elegant approach is to chemically tether CPs on the QD surface (i.e., preparing CP­QD nanocomposites

  15. Designs for high power, single mode operation in broad stripe semiconductor lasers

    E-Print Network [OSTI]

    Lai, Chun Por

    1988-01-01T23:59:59.000Z

    -heterostructure (DH) (Figure 1b) laser was found to achieve improved confinement oi' recombination radiation in the active layer of the device. Such a device consists of a. layer of semiconducting material sandwiched between two cladding layers of a dif... heterostructure laser with the active region having a lower energy band gap compared to that of the cladding layers. The electrons and holes can move freely to the active region under I'orward bias in a heterostructure laser. However, once there, they can...

  16. Apparatus for the etching for semiconductor devices

    SciTech Connect (OSTI)

    Reinberg, A.R.; Steinberg, G.N.

    1983-01-11T23:59:59.000Z

    Apparatus for the etching of semiconductor devices which includes, in combination, an etching chamber containing the semiconductor device to be etched, an electrodeless etching plasma forming chamber having an inlet connected to a source of continuously flowing etching gas and having an outlet connected to said etching chamber in fluid flow communication; a helical inductive resonator coupler for coupling a source of R.F. electrical power into the electrodeless plasma forming chamber for continuously forming etching plasma from the etching gas flowing therethrough; this inductive resonator coupler including a grounded hollow cylinder of electrically conductive material, with a grounded base member at one end; a helically coiled wire conductor concentrically mounted within the cylinder and spaced from the inner walls thereof; the plasma forming chamber being mounted substantially concentrically within the coil, the end of the coil toward the base member being grounded; and an electrical coupling for applying into the coil an R.F. source of electrical power at a position near, but spaced from, the grounded end thereof.

  17. Coated semiconductor devices for neutron detection

    DOE Patents [OSTI]

    Klann, Raymond T. (Bolingbrook, IL); McGregor, Douglas S. (Whitmore Lake, MI)

    2002-01-01T23:59:59.000Z

    A device for detecting neutrons includes a semi-insulated bulk semiconductor substrate having opposed polished surfaces. A blocking Schottky contact comprised of a series of metals such as Ti, Pt, Au, Ge, Pd, and Ni is formed on a first polished surface of the semiconductor substrate, while a low resistivity ("ohmic") contact comprised of metals such as Au, Ge, and Ni is formed on a second, opposed polished surface of the substrate. In one embodiment, n-type low resistivity pinout contacts comprised of an Au/Ge based eutectic alloy or multi-layered Pd/Ge/Ti/Au are also formed on the opposed polished surfaces and in contact with the Schottky and ohmic contacts. Disposed on the Schottky contact is a neutron reactive film, or coating, for detecting neutrons. The coating is comprised of a hydrogen rich polymer, such as a polyolefin or paraffin; lithium or lithium fluoride; or a heavy metal fissionable material. By varying the coating thickness and electrical settings, neutrons at specific energies can be detected. The coated neutron detector is capable of performing real-time neutron radiography in high gamma fields, digital fast neutron radiography, fissile material identification, and basic neutron detection particularly in high radiation fields.

  18. Visible-wavelength semiconductor lasers and arrays

    DOE Patents [OSTI]

    Schneider, R.P. Jr.; Crawford, M.H.

    1996-09-17T23:59:59.000Z

    The visible semiconductor laser includes an InAlGaP active region surrounded by one or more AlGaAs layers on each side, with carbon as the sole p-type dopant. Embodiments of the invention are provided as vertical-cavity surface-emitting lasers (VCSELs) and as edge-emitting lasers (EELs). One or more transition layers comprised of a substantially indium-free semiconductor alloy such as AlAsP, AlGaAsP, or the like may be provided between the InAlGaP active region and the AlGaAS DBR mirrors or confinement layers to improve carrier injection and device efficiency by reducing any band offsets. Visible VCSEL devices fabricated according to the invention with a one-wavelength-thick (1{lambda}) optical cavity operate continuous-wave (cw) with lasing output powers up to 8 mW, and a peak power conversion efficiency of up to 11%. 5 figs.

  19. 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.

  20. A 10-kW SiC Inverter with A Novel Printed Metal Power Module With Integrated Cooling Using Additive Manufacturing

    SciTech Connect (OSTI)

    Chinthavali, Madhu Sudhan [ORNL; Ayers, Curtis William [ORNL; Campbell, Steven L [ORNL; Wiles, Randy H [ORNL; Ozpineci, Burak [ORNL

    2014-01-01T23:59:59.000Z

    With efforts to reduce the cost, size, and thermal management systems for the power electronics drivetrain in hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs), wide band gap semiconductors including silicon carbide (SiC) have been identified as possibly being a partial solution. This paper focuses on the development of a 10-kW all SiC inverter using a high power density, integrated printed metal power module with integrated cooling using additive manufacturing techniques. This is the first ever heat sink printed for a power electronics application. About 50% of the inverter was built using additive manufacturing techniques.