National Library of Energy BETA

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)

    2010-12-14

    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.

    1985-01-10

    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. Wide band-gap nanowires for light emitting diodes

    E-Print Network [OSTI]

    Chesin, Jordan (Jordan Paul)

    2015-01-01

    Wide band-gap nanowires composed of GaN and ZnO are promising materials for unique designs and potential efficiency improvement of light emitting diodes (LEDs) for solid state lighting. The large surface-to-volume ratio ...

  4. The energy band gap of a semiconductor material critically influences the operating wavelength in an optoelectronic device. Realization of any desired band gap, or even spatially graded band gaps, is important

    E-Print Network [OSTI]

    :00 PM; ERC 490 School for Engineering of Matter, Transport and Energy #12;The energy band gap of a semiconductor material critically influences the operating wavelength for applications such as lasers, light-emitting diodes (LEDs), solar cells, and detectors. New band gaps can

  5. Band-Gap Engineering at a Semiconductor-Crystalline Oxide Interface

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

    Jahangir-Moghadam, Mohammadreza; Ahmadi-Majlan, Kamyar; Shen, Xuan; Droubay, Timothy; Bowden, Mark; Chrysler, Matthew; Su, Dong; Chambers, Scott A.; Ngai, Joseph H.

    2015-02-09

    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. Characterization of Novel Semiconductor Alloys for Band Gap Engineering

    E-Print Network [OSTI]

    Broesler, Robert Joseph

    2010-01-01

    of Semiconductors: Physics and Materials Properties. 1999,in Properties of Advanced Semiconductor Materials GaN, AlN,Semiconductor Alloys: InAlN, ZnSeO and GaNAs 2 Materials Properties

  7. 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.

    2008-03-18

    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.

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

    E-Print Network [OSTI]

    Truhlar, Donald G

    .3,6,7 However, the computational cost for HF exchange in solid-state physics calculations is very indirect.24 In this paper we calculate the lowest excitation energy whether direct or in- direct by Eq. 1Calculation of semiconductor band gaps with the M06-L density functional Yan Zhao and Donald G

  9. 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)

    2009-09-15

    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.

  10. 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

  11. Inter-band optoelectronic properties in quantum dot structure of low band gap III-V semiconductors

    SciTech Connect (OSTI)

    Dey, Anup; Maiti, Biswajit; Chanda, Debasree

    2014-04-14

    A generalized theory is developed to study inter-band optical absorption coefficient (IOAC) and material gain (MG) in quantum dot structures of narrow gap III-V compound semiconductor considering the wave-vector (k{sup ?}) dependence of the optical transition matrix element. The band structures of these low band gap semiconducting materials with sufficiently separated split-off valance band are frequently described by the three energy band model of Kane. This has been adopted for analysis of the IOAC and MG taking InAs, InSb, Hg{sub 1?x}Cd{sub x}Te, and In{sub 1?x}Ga{sub x}As{sub y}P{sub 1?y} lattice matched to InP, as example of III–V compound semiconductors, having varied split-off energy band compared to their bulk band gap energy. It has been found that magnitude of the IOAC for quantum dots increases with increasing incident photon energy and the lines of absorption are more closely spaced in the three band model of Kane than those with parabolic energy band approximations reflecting the direct the influence of energy band parameters. The results show a significant deviation to the MG spectrum of narrow-gap materials having band nonparabolicity compared to the parabolic band model approximations. The results reflect the important role of valence band split-off energies in these narrow gap semiconductors.

  12. 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.

    2009-06-07

    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.

  13. Near-edge band structures and band gaps of Cu-based semiconductors predicted by the modified Becke-Johnson potential plus an on-site Coulomb U

    SciTech Connect (OSTI)

    Zhang, Yubo; Zhang, Jiawei; Wang, Youwei; Gao, Weiwei; Abtew, Tesfaye A.; Zhang, Peihong E-mail: wqzhang@mail.sic.ac.cn; Beijing Computational Science Research Center, Beijing 100084 ; Zhang, Wenqing E-mail: wqzhang@mail.sic.ac.cn; School of Chemistry and Chemical Engineering and Sate Key Laboratory of Coordination Chemistry, Nanjing University, Jiangsu 210093

    2013-11-14

    Diamond-like Cu-based multinary semiconductors are a rich family of materials that hold promise in a wide range of applications. Unfortunately, accurate theoretical understanding of the electronic properties of these materials is hindered by the involvement of Cu d electrons. Density functional theory (DFT) based calculations using the local density approximation or generalized gradient approximation often give qualitative wrong electronic properties of these materials, especially for narrow-gap systems. The modified Becke-Johnson (mBJ) method has been shown to be a promising alternative to more elaborate theory such as the GW approximation for fast materials screening and predictions. However, straightforward applications of the mBJ method to these materials still encounter significant difficulties because of the insufficient treatment of the localized d electrons. We show that combining the promise of mBJ potential and the spirit of the well-established DFT + U method leads to a much improved description of the electronic structures, including the most challenging narrow-gap systems. A survey of the band gaps of about 20 Cu-based semiconductors calculated using the mBJ + U method shows that the results agree with reliable values to within ±0.2 eV.

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

    SciTech Connect (OSTI)

    Dickinson, J. T.

    2014-04-05

    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.

  15. 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

    2012-06-11

    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.

  16. The energy band gap in the excitation spectrum is a fundamental characteristic for a broad array of materials. In the 1980's, the "band-gap" problem in semiconductors, the systematic underestimation of

    E-Print Network [OSTI]

    Braun, Paul

    The energy band gap in the excitation spectrum is a fundamental characteristic for a broad array for the electron self energy. I will outline the basic physical ingredients of the modern many-body perturbation for use in photocatalysis. In particular, I will discuss the application to energy level alignment

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

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

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

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

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

    in a significant band gap, 0.26 electron volts (eV), an important step toward making graphene useful as a semiconductor. Left: In graphene's electronic band structure, the...

  19. Electronically Nonalloyed State of a Statistical Single Atomic Layer Semiconductor Alloy

    E-Print Network [OSTI]

    Dunin-Borkowski, Rafal E.

    spectroscopy Alloying different semiconductor compounds attracted wide attention, since the material properties formed semiconductor alloy has spatially homogeneous properties; that is, the original materials semiconductor materials with, for example, intentionally designed band gaps, lattice constants, and/or optical

  20. 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

  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 U.S. Department of Energy Fuel Cell Technologies Office Presenters: Jeff...

  2. Photonic band gap structure simulator

    DOE Patents [OSTI]

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

    2006-10-03

    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.

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

    DOE Patents [OSTI]

    Wanlass, Mark W. (Golden, CO)

    1994-01-01

    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.

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

    DOE Patents [OSTI]

    Wanlass, Mark W.; Mascarenhas, Angelo

    2006-08-22

    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.

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

    DOE Patents [OSTI]

    Wanlass, M. W.; Mascarenhas, A.

    2006-08-22

    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.

  6. 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

    Band-Gap Engineering of Zinc Oxide Colloids via Lattice Substitution with Sulfur Leading requires a precise control over electronic properties. Zinc oxide is favorable for large the full inorganic UV protection are made. KEYWORDS: metal oxides, semiconductors, band gap engineering

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

    DOE Patents [OSTI]

    Wanlass, M.W.

    1994-12-27

    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.

  8. L-asparagine crystals with wide gap semiconductor features: Optical absorption measurements and density functional theory computations

    SciTech Connect (OSTI)

    Zanatta, G.; Gottfried, C.; Silva, A. M.; Caetano, E. W. S.; Sales, F. A. M.; Freire, V. N.

    2014-03-28

    Results of optical absorption measurements are presented together with calculated structural, electronic, and optical properties for the anhydrous monoclinic L-asparagine crystal. Density functional theory (DFT) within the generalized gradient approximation (GGA) including dispersion effects (TS, Grimme) was employed to perform the calculations. The optical absorption measurements revealed that the anhydrous monoclinic L-asparagine crystal is a wide band gap material with 4.95 eV main gap energy. DFT-GGA+TS simulations, on the other hand, produced structural parameters in very good agreement with X-ray data. The lattice parameter differences ?a, ?b, ?c between theory and experiment were as small as 0.020, 0.051, and 0.022 Å, respectively. The calculated band gap energy is smaller than the experimental data by about 15%, with a 4.23 eV indirect band gap corresponding to Z???? and Z???? transitions. Three other indirect band gaps of 4.30 eV, 4.32 eV, and 4.36 eV are assigned to ?3 ???, ?1 ???, and ?2 ??? transitions, respectively. ?-sol computations, on the other hand, predict a main band gap of 5.00 eV, just 50 meV above the experimental value. Electronic wavefunctions mainly originating from O 2p–carboxyl, C 2p–side chain, and C 2p–carboxyl orbitals contribute most significantly to the highest valence and lowest conduction energy bands, respectively. By varying the lattice parameters from their converged equilibrium values, we show that the unit cell is less stiff along the b direction than for the a and c directions. Effective mass calculations suggest that hole transport behavior is more anisotropic than electron transport, but the mass values allow for some charge mobility except along a direction perpendicular to the molecular layers of L-asparagine which form the crystal, so anhydrous monoclinic L-asparagine crystals could behave as wide gap semiconductors. Finally, the calculations point to a high degree of optical anisotropy for the absorption and complex dielectric function, with more structured curves for incident light polarized along the 100 and 101 directions.

  9. Advances in wide bandgap materials for semiconductor spintronics

    E-Print Network [OSTI]

    Hebard, Arthur F.

    Advances in wide bandgap materials for semiconductor spintronics S.J. Pearton1,* , C.R. Abernathy1 or light emission. The relatively new field of semiconductor spintronics seeks, in addition, to exploit Elsevier Science B.V. All rights reserved. Keywords: Wide bandgap materials; Semiconductor; Spintronics 1

  10. Band-gap tailoring of ZnO by means of heavy Al doping

    SciTech Connect (OSTI)

    Sernelius, B.E.; Berggren, K.; Jin, Z.; Hamberg, I.; Granqvist, C.G.

    1988-06-15

    Films of ZnO:Al were produced by weakly reactive dual-target magnetron sputtering. Optical band gaps, evaluated from spectrophotometric data, were widened in proportion to the Al doping. The widening could be quantitatively reconciled with an effective-mass model for n-doped semiconductors, provided the polar character of ZnO was accounted for.

  11. 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 ...

  12. 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...

  13. Effect of Hydrogen Passivation on the Electronic Structure of Ionic Semiconductor Nanostructures

    SciTech Connect (OSTI)

    Deng, H. X.; Li, S. S.; Li, J. B.; Wei, S. H.

    2012-05-15

    In theoretical studies of thin film and nanostructured semiconductors, pseudohydrogen (PH) is widely used to passivate the surface dangling bonds. Based on these calculations, it is often believed that nanostructured semiconductors, due to quantum confinement, have a larger band gap than their bulk counterparts. Using first-principles band structure theory calculation and comparing systematically the differences between PH-passivated and real-hydrogen-passivated (RH-passivated) semiconductor surfaces and nanocrystals, we show that, unlike PH passivation that always increases the band gap with respect to the bulk value, RH passivation of the nanostructured semiconductors can either increase or decrease the band gap, depending on the ionicity of the nanocompounds. The differences between PH and RH passivations decreases when the covalency of the semiconductor increases and can be explained using a band coupling model. This observation greatly increases the tunability of nanostructured semiconductor properties, especially for wide-gap ionic semiconductors.

  14. Wide-Bandgap Compound Semiconductors to Enable Novel Semiconductor Devices

    SciTech Connect (OSTI)

    Crawford, M.H.; Chow, W.W.; Wright, A.F.; Lee, S.R.; Jones, E.D.; Han, J.; Shul, R.J.

    1999-04-01

    This report represents the completion of a three-year Laboratory-Directed Research and Development (LDRD) program that focused on research and development of GaN-based wide bandgap semiconductor materials (referred to as III-N materials). Our theoretical investigations include the determination of fundamental materials parameters from first-principles calculations, the study of gain properties of III-N heterostructures using a microscopic laser theory and density-functional-theory, charge-state calculations to determine the core structure and energy levels of dislocations in III-N materials. Our experimental investigations include time-resolved photoluminescence and magneto-luminescence studies of GaN epilayers and multiquantum well samples as well as x-ray diffraction studies of AlGaN ternary alloys. In addition, we performed a number of experiments to determine how various materials processing steps affect both the optical and electrical properties of GaN-based materials. These studies include photoluminescence studies of GaN epilayers after post-growth rapid thermal annealing, ion implantation to produce n- and p-type material and electrical and optical studies of plasma-etched structures.

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

    SciTech Connect (OSTI)

    Ozpineci, B.

    2004-01-02

    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.

  16. 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

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

    SciTech Connect (OSTI)

    Henry Hao-Chuan Kang

    2004-12-19

    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.

  18. Characterization of Novel Semiconductor Alloys for Band Gap Engineering

    E-Print Network [OSTI]

    Broesler, Robert Joseph

    2010-01-01

    et al. High Efficiency InAlN-based solar cells. in PVSC '08.for low-cost and high-efficiency solar cells and efficientyielded the record for solar cell efficiency without lattice

  19. Characterization of Novel Semiconductor Alloys for Band Gap Engineering

    E-Print Network [OSTI]

    Broesler, Robert Joseph

    2010-01-01

    xAsx Alloys for Multi-junction Solar Cells. in PVSC '10.for single and multi-junction solar cells along with thematerial system multi-junction solar cell [12]. High quality

  20. Synthesis of electromagnetic modes in photonic band gap fibers

    E-Print Network [OSTI]

    Hu, Qichao

    2007-01-01

    In this paper, we report on the successful synthesis of three individual modes, HE11, TEo0, and TE02 for transmission in photonic band gap fibers at near infrared wavelengths. We measure the propagation losses of the HE11 ...

  1. Substrate-induced band gap opening in epitaxial graphene

    E-Print Network [OSTI]

    2008-01-01

    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. Band Gap Engineering of Poly(p-phenyleneethynylene)s

    E-Print Network [OSTI]

    Myrick, Michael Lenn

    Band Gap Engineering of Poly(p-phenyleneethynylene)s: Cross-Conjugated PPE-PPV Hybrids James N. Reaction of 2 with the aldehydes 3a-f in the presence of sodium hydride in THF furnishes the diiodides 4

  3. Photonic-Band-Gap Traveling-Wave Gyrotron Amplifier

    E-Print Network [OSTI]

    Nanni, Emilio Alessandro

    We report the experimental demonstration of a gyrotron traveling-wave-tube amplifier at 250 GHz that uses a photonic band gap (PBG) interaction circuit. The gyrotron amplifier achieved a peak small signal gain of 38 dB and ...

  4. Highly dispersive photonic band-gap-edge optofluidic biosensors

    E-Print Network [OSTI]

    Xiao, S; Xiao, Sanshui; Mortensen, Niels Asger

    2006-01-01

    Highly dispersive photonic band-gap-edge optofluidic biosensors are studied theoretically. We demonstrate that these structures are strongly sensitive to the refractive index of the liquid, which is used to tune dispersion of the photonic crystal. The upper frequency band-gap edge shifts about 1.8 nm for dn=0.002, which is quite sensitive. Results from transmission spectra agree well with those obtained from the band structure theory.

  5. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield Municipal Gas &SCE-Sessions |discussed how saving energy could betold youExamplesAofOurWide Bandgap

  6. INFOGRAPHIC: 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverse (JournalvivoHighHussein KhalilResearch8 IEEE TRANSACTIONSIIILet's Get toWide

  7. Prediction of a low band gap oxide ferroelectric

    SciTech Connect (OSTI)

    Xu, Bo [National University of Singapore; Singh, David J [ORNL; Cooper, Valentino R [ORNL; Feng, Yuan Ping [National University of Singapore

    2011-01-01

    A strategy for obtaining low band gap oxide ferroelectrics based on charge imbalance is described and illustrated by first-principles studies of the hypothetical compound Bi{sub 6}Ti{sub 4}O{sub 17}, which is an alternate stacking of the ferroelectric Bi{sub 4}Ti{sub 3}O{sub 12}. We find that this compound is ferroelectric, similar to Bi{sub 4}Ti{sub 3}O{sub 12} although with a reduced polarization. Importantly, calculations of the electronic structure with the recently developed functional of Tran and Blaha yield a much reduced band gap of 1.83 eV for this material compared to Bi{sub 4}Ti{sub 3}O{sub 12}. Therefore, Bi{sub 6}Ti{sub 4}O{sub 17} is predicted to be a low band gap ferroelectric material.

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

    SciTech Connect (OSTI)

    Wang, Fenggong Grinberg, Ilya; Rappe, Andrew M.

    2014-04-14

    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.

  9. Semiconductor-based photoelectrochemical water splitting at the limit of very wide depletion region

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

    Liu, Mingzhao; Lyons, John L.; Yan, Danhua H.; Hybertsen, Mark S.

    2015-11-23

    In semiconductor-based photoelectrochemical (PEC) water splitting, carrier separation and delivery largely relies on the depletion region formed at the semiconductor/water interface. As a Schottky junction device, the trade-off between photon collection and minority carrier delivery remains a persistent obstacle for maximizing the performance of a water splitting photoelectrode. Here, it is demonstrated that the PEC water splitting efficiency for an n-SrTiO3 (n-STO) photoanode is improved very significantly despite its weak indirect band gap optical absorption (? 3 photoanodes are fabricated with their bulkmore »heavily doped with oxygen vacancies but their surface lightly doped over a tunable depth of a few hundred nanometers, through a simple low temperature re-oxidation technique. The graded doping profile widens the depletion region to over 500 nm, thus leading to very efficient charge carrier separation and high quantum efficiency (>70%) for the weak indirect transition. As a result, this simultaneous optimization of the light absorption, minority carrier (hole) delivery, and majority carrier (electron) transport by means of a graded doping architecture may be useful for other indirect band gap photocatalysts that suffer from a similar problem of weak optical absorption.« less

  10. Special purpose modes in photonic band gap fibers

    DOE Patents [OSTI]

    Spencer, James; Noble, Robert; Campbell, Sara

    2013-04-02

    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.

  11. Substrate-induced band gap opening in epitaxial graphene

    E-Print Network [OSTI]

    2008-01-01

    step to make graphene a semiconductor is to dope grapheneDirac points, graphene is a zero gap semiconductor, and howconventional semiconductors. In single layer graphene, the

  12. 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)

    2001-01-01

    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.

  13. 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)

    2014-08-14

    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.

  14. Ultrafast optical switching of three-dimensional Si inverse opal photonic band gap crystals

    E-Print Network [OSTI]

    Vos, Willem L.

    Ultrafast optical switching of three-dimensional Si inverse opal photonic band gap crystals Tijmen on three-dimensional photonic band gap crystals. Switching the Si inverse opal is achieved by optically

  15. 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)

    2014-05-07

    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.

  16. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effect PhotovoltaicsStructureInnovation PortalSubstrate-Induced Band-Gap Opening

  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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effect PhotovoltaicsStructureInnovation PortalSubstrate-Induced Band-Gap

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

    DOE Patents [OSTI]

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

    2008-03-18

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

  19. Evidence of surface acoustic wave band gaps in the phononic crystals created on thin plates

    E-Print Network [OSTI]

    Deymier, Pierre

    Evidence of surface acoustic wave band gaps in the phononic crystals created on thin plates Xinya acoustic wave SAW band gaps. In this letter, we report a new type of phononic crystals manufactured Institute of Physics. DOI: 10.1063/1.2167794 The propagation of acoustic waves in periodic composite

  20. 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, "Light harvesting improvement of organic solar cells with self- enhanced active layer designs," Opt

  1. A Class of Supported Membranes: Formation of Fluid Phospholipid Bilayers on Photonic Band Gap Colloidal Crystals

    E-Print Network [OSTI]

    Parikh, Atul N.

    Colloidal Crystals Adrian M. Brozell, Michelle A. Muha, Babak Sanii, and Atul N. Parikh* Department tunable colloidal crystal with a well-defined photonic band gap. Monodisperse colloids (e.g., silica-defined photonic band gap (PBG).6 The ability to couple membranes with colloidal crystals opens useful optical

  2. 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...

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

    Office of Energy Efficiency and Renewable Energy (EERE)

    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.

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

    SciTech Connect (OSTI)

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

    2014-09-28

    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 mm². It is shown that electron densities larger than 10¹? cm ?³ are needed in order to create an effective one-dimensional electromagnetic band gap structure. Some applications for using the one-dimensional electromagnetic band gap structure in waveguide as a control of microwave (broadband filter and device for variation of pulse duration) are demonstrated.

  5. Robust topology optimization of three-dimensional photonic-crystal band-gap structures

    E-Print Network [OSTI]

    Lee, K. Y. K.

    We perform full 3D topology optimization (in which “every voxel” of the unit cell is a degree of freedom) of photonic-crystal structures in order to find optimal omnidirectional band gaps for various symmetry groups, ...

  6. 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 ...

  7. 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)

    2000-01-01

    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.

  8. Photocell utilizing a wide-bandgap semiconductor material

    DOE Patents [OSTI]

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

    1984-06-05

    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.

  9. 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)

    2014-08-25

    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.

  10. Science and applications of infrared semiconductor nanocrystals

    E-Print Network [OSTI]

    Geyer, Scott Mitchell

    2010-01-01

    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 ...

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

    E-Print Network [OSTI]

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

    2010-01-01

    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. Structural studies and band gap tuning of Cr doped ZnO nanoparticles

    SciTech Connect (OSTI)

    Srinet, Gunjan Kumar, Ravindra Sajal, Vivek

    2014-04-24

    Structural and optical properties of Cr doped ZnO nanoparticles prepared by the thermal decomposition method are presented. X-ray diffraction studies confirmed the substitution of Cr on Zn sites without changing the wurtzite structure of ZnO. Modified form of W-H equations was used to calculate various physical parameters and their variation with Cr doping is discussed. Significant red shift was observed in band gap, i.e., a band gap tuning is achieved by Cr doping which could eventually be useful for optoelectronic applications.

  13. 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

    2010-09-20

    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.

  14. Band gap narrowing in zinc oxide-based semiconductor thin films...

    Office of Scientific and Technical Information (OSTI)

    ABSORPTION; ALUMINIUM COMPOUNDS; BORON COMPOUNDS; CHARGE CARRIERS; CONCENTRATION RATIO; DENSITY; DOPED MATERIALS; ELECTRONIC STRUCTURE; ENERGY GAP; GALLIUM COMPOUNDS; INDIUM...

  15. Anomalous composition dependence of the band gap pressure coefficients in In-containing nitride semiconductors

    E-Print Network [OSTI]

    Svane, Axel Torstein

    . Svane5 1 Institute of High Pressures Physics, Polish Academy of Sciences, Warsaw, Poland 2Institute of Physics, Polish Academy of Sciences, Warsaw, Poland 3CRHEA-CNRS, Sophia Antipolis, Valbonne, France 4 Institute of Condensed Matter Physics, �cole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne

  16. Calculation of band gaps in molecular crystals using hybrid functional theory

    E-Print Network [OSTI]

    Perger, Warren F.

    , pentaerythritol (PE), pentaerythritol tetranitrate (PETN), and cyclotrimethylene trinitramine (RDX). The B3LYP (PETN) , and cyclotrimethylene trinitramine (RDX). Molecular crystals have not been as Preprint, in this case the molecular crystals anthracene, PE, PETN and RDX. In addition to the relevance of the band gap

  17. 2008 IEEE Electrical Performance of Electronic Packaging Suppression of Vertical Coupling using Electromagnetic Band Gap Structures

    E-Print Network [OSTI]

    Swaminathan, Madhavan

    2008 IEEE Electrical Performance of Electronic Packaging Suppression of Vertical Coupling using Electromagnetic Band Gap Structures Nithya Sankaran, Suzanne Huh, Madhavan Swaminathan and Rao Tummala Packaging are presented. I. Introduction Multilayer packaging plays a vital role in producing highly miniaturized, low

  18. Photonic band gap in isotropic hyperuniform disordered solids with low dielectric contrast

    E-Print Network [OSTI]

    Torquato, Salvatore

    , "Photonic amorphous diamond Structure with a 3D photonic band gap," Phys. Rev. Lett. 100(1), 013901 (2008 design) not limited by crystalline symmetries. ©2013 Optical Society of America OCIS codes: (160.0160) Materials; (160.5293) Photonic bandgap materials; (160.5298) Photonic crystals. References and links 1. S

  19. Tunable band gap in graphene with a noncentrosymmetric superlattice potential Rakesh P. Tiwari and D. Stroud

    E-Print Network [OSTI]

    Stroud, David

    superlattice TGS or a square graphene superlattice with broken inversion symmetry, and find that a band gap is created at the original and, in the case of a TGS, the "second generation" Dirac point. This gap, which, a triangular graphene superlattice TGS was considered, and a new class of massless Dirac fermions was predicted

  20. Electronegativity calculation of bulk modulus and band gap of ternary ZnO-based alloys

    SciTech Connect (OSTI)

    Li, Keyan; Kang, Congying [State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China)] [State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China); Xue, Dongfeng, E-mail: dongfeng@ciac.jl.cn [State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China) [State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China); State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

    2012-10-15

    In this work, the bulk moduli and band gaps of M{sub x}Zn{sub 1?x}O (M = Be, Mg, Ca, Cd) alloys in the whole composition range were quantitatively calculated by using the electronegativity-related models for bulk modulus and band gap, respectively. We found that the change trends of bulk modulus and band gap with an increase of M concentration x are same for Be{sub x}Zn{sub 1?x}O and Cd{sub x}Zn{sub 1?x}O, while the change trends are reverse for Mg{sub x}Zn{sub 1?x}O and Ca{sub x}Zn{sub 1?x}O. It was revealed that the bulk modulus is related to the valence electron density of atoms whereas the band gap is strongly influenced by the detailed chemical bonding behaviors of constituent atoms. The current work provides us a useful guide to compositionally design advanced alloy materials with both good mechanical and optoelectronic properties.

  1. Generation of color centers by femtosecond laser pulses in wide band gap materials

    E-Print Network [OSTI]

    Dickinson, J. Thomas

    reactions restore a rather large fraction of the transparency lost during irradiation. In the case of soda is easily accomplished. 2. EXPERIMENT Femtosecond laser pulses were produced by a Spectra Physics Hurricane

  2. Band gaps and structural properties of graphene halides and their derivates: A hybrid functional study with localized orbital basis sets

    E-Print Network [OSTI]

    Karlický, František; Otyepka, Michal; 10.1063/1.4736998

    2012-01-01

    DFT calculations of the electronic structure of graphane and stoichiometrically halogenated graphene derivatives (fluorographene and other analogous graphene halides) show (i) localized orbital basis sets can be successfully and effectively used for such 2D materials; (ii) several functionals predict that the band gap of graphane is greater than that of fluorographene, whereas HSE06 gives the opposite trend; (iii) HSE06 functional predicts quite good values of band gaps w.r.t benchmark theoretical and experimental data; (iv) the zero band gap of graphene is opened by hydrogenation and halogenation and strongly depends on the chemical composition of mixed graphene halides; (v) the stability of graphene halides decreases sharply with increasing size of the halogen atom - fluorographene is stable, whereas graphene iodide spontaneously decomposes. In terms of band gap and stability, the C2FBr, and C2HBr derivatives seem to be promising materials, e.g., for (opto)electronics applications, because their band gaps a...

  3. Reflection technique for thermal mapping of semiconductors

    DOE Patents [OSTI]

    Walter, Martin J. (Lee, NY)

    1989-06-20

    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.

  4. 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

    2013-12-24

    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.

  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)

    2010-09-30

    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)

    2014-07-21

    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. Strain-induced energy band gap opening in two-dimensional bilayered silicon film

    E-Print Network [OSTI]

    Ji, Zhonghang; Voon, Lok C Lew Yan; Zhuang, Yan

    2015-01-01

    This work presents a theoretical study of the structural and electronic properties of bilayered silicon films under in-plane biaxial strain/stress using density functional theory. Atomic structures of the two-dimensional silicon films are optimized by using both the local-density approximation and generalized gradient approximation. In the absence of strain/stress, five buckled hexagonal honeycomb structures of the bilayered silicon film have been obtained as local energy minima and their structural stability has been verified. These structures present a Dirac-cone shaped energy band diagram with zero energy band gaps. Applying tensile biaxial strain leads to a reduction of the buckling height. Atomically flat structures with zero bucking height have been observed when the AA-stacking structures are under a critical biaxial strain. Increase of the strain between 10.7% ~ 15.4% results in a band-gap opening with a maximum energy band gap opening of ~168.0 meV obtained when 14.3% strain is applied. Energy band d...

  8. 2010 Defects in Semiconductors GRC

    SciTech Connect (OSTI)

    Shengbai Zhang

    2011-01-06

    Continuing its tradition of excellence, this Gordon Conference will focus on research at the forefront of the field of defects in semiconductors. The conference will have a strong emphasis on the control of defects during growth and processing, as well as an emphasis on the development of novel defect detection methods and first-principles defect theories. 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 will deal with point and extended defects in a broad range of electronic materials. This approach has proved to be extremely fruitful for advancing fundamental understanding in emerging materials such as wide-band-gap semiconductors, oxides, sp{sup 2} carbon based-materials, and photovoltaic/solar cell materials, and in understanding important defect phenomena such as doping bottleneck in nanostructures and the diffusion of defects and impurities. The program consists of about twenty invited talks and a number of contributed poster sessions. The emphasis should be on work which has yet to be published. The large amount of discussion time provides an ideal forum for dealing with topics that are new and/or controversial.

  9. 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)

    2012-12-01

    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.

  10. 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

    2013-10-22

    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.

  11. 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)

    2013-04-15

    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.

  12. Is it effective to harvest visible light by decreasing the band gap of photocatalytic materials?

    SciTech Connect (OSTI)

    Fu Ning; Tang Xinhu; Li Dongyang [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2G6 (Canada)

    2012-02-27

    In situ variations in the electron work function and photo-current of TiO{sub 2} nanotubes demonstrate that long-wavelength illumination only has a minor effect on the excitation of electrons in the nanotubes after being exposed to short-wavelength light or when the short-wavelength light coexisted, indicating that the solar spectrum may not be utilized as efficiently as expected by extending the absorption spectrum of the photocatalytic material to visible light range with decreased band gaps.

  13. A new generalized KohnSham method for fundamental band-gaps in solids

    E-Print Network [OSTI]

    Baer, Roi

    known to be rigorously correct for the Fermi level.3,4 The fundamental band-gap of the solid, Eg-state energies, Egs, of the N À 1, N and N + 1 electron systems as follows: Eg ¼ IP À EA ¼ lim N!1 EgsðN À 1Þ À 2 particles and can be expressed as follows: Eg = ÀeN,N + eN + 1,N+1 = (eN,N+1 À eN,N) + DXC (1.2) Where e

  14. Photonic band gaps in three-dimensional network structures with short-range order

    SciTech Connect (OSTI)

    Liew, Seng Fatt; Noh, Heeso; Yang, Jin-Kyu; Schreck, Carl F.; Dufresne, Eric R.; O'Hern, Corey S.; Cao, Hui

    2011-12-15

    We present a systematic study of photonic band gaps (PBGs) in three-dimensional (3D) photonic amorphous structures (PASs) with short-range order. From calculations of the density of optical states (DOS) for PASs with different topologies, we find that tetrahedrally connected dielectric networks produce the largest isotropic PBGs. Local uniformity and tetrahedral order are essential to the formation of PBGs in PASs, in addition to short-range geometric order. This work demonstrates that it is possible to create broad, isotropic PBGs for vector light fields in 3D PASs without long-range order.

  15. 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)

    1994-08-02

    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.

  16. Electronic properties of hybrid organicinorganic semiconductors B. Fluegel, Y. Zhang, and A. Mascarenhas

    E-Print Network [OSTI]

    Li, Jing

    Electronic properties of hybrid organic­inorganic semiconductors B. Fluegel, Y. Zhang, and A semiconductor band gaps and lattice constants. The gradual exhaustion of usable new inorganic material; published 8 November 2004) Hybrid semiconductors comprising networks of inorganic II­VI semiconductor

  17. 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

    2011-01-01

    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.

  18. Photonic-band-gap effects in two-dimensional polycrystalline and amorphous structures

    SciTech Connect (OSTI)

    Yang, Jin-Kyu; Noh, Heeso; Liew, Seng-Fatt; Schreck, Carl; Guy, Mikhael I.; O'Hern, Corey S.; Cao, Hui

    2010-11-15

    We study numerically the density of optical states (DOS) in two-dimensional photonic structures with short-range positional order and observe a transition from polycrystalline to amorphous photonic systems. In polycrystals, photonic band gaps (PBGs) are formed within individual domains, which leads to a depletion of the DOS similar to that in periodic structures. In amorphous photonic media, the domain sizes are too small to form PBGs, thus the depletion of the DOS is weakened significantly. The critical domain size that separates the polycrystalline and amorphous regimes is determined by the attenuation length of Bragg scattering, which depends not only on the degree of positional order but also the refractive-index contrast of the photonic material. Even with relatively low-refractive-index contrast, we find that modest short-range positional order in photonic structures enhances light confinement via collective scattering and interference.

  19. 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

    2015-01-01

    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...

  20. 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 ...

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

    E-Print Network [OSTI]

    Pereira, LMC; Wahl, U

    Scientific 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 fe...

  2. 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

  3. Transmission and dispersion relations of perfect and defect-containing waveguide structures in phononic band gap materials

    E-Print Network [OSTI]

    Deymier, Pierre

    Transmission and dispersion relations of perfect and defect-containing waveguide structures investigate transmission through perfect linear waveguides, waveguides containing a resonant cavity a large frequency range of the band gap by varying the width of the guide. The transmission through

  4. Photonic band gap templating using optical interference lithography Timothy Y. M. Chan, Ovidiu Toader, and Sajeev John

    E-Print Network [OSTI]

    John, Sajeev

    band gap material-based optical microchip, it is necessary to have high quality, three-dimensional 3D dielectric structure of the PBG material, it is possible to guide light through micron-scale, single-mode air, and replication 11,12 have made this paramount goal a near term reality. The optical properties of PBG materials

  5. Band gap engineering strategy via polarization rotation in perovskite ferroelectrics Fenggong Wang, Ilya Grinberg, and Andrew M. Rappe

    E-Print Network [OSTI]

    Rappe, Andrew M.

    Band gap engineering strategy via polarization rotation in perovskite ferroelectrics Fenggong Wang.1063/1.4804367 Strain sensitivity of polarization in perovskite ferroelectrics Appl. Phys. Lett. 93, 122903 (2008); 10.1063/1.2988263 Domain engineering of the transverse piezoelectric coefficient in perovskite ferroelectrics J. Appl. Phys

  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. The experimental evidence that grading improves device performance, however, has not been compelling, mostly

  7. 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

  8. Effects of the Cu off-stoichiometry on transport properties of wide gap p-type semiconductor, layered oxysulfide LaCuSO

    SciTech Connect (OSTI)

    Goto, Yosuke, E-mail: ygoto@z8.keio.jp; Tanaki, Mai; Okusa, Yuki; Matoba, Masanori; Kamihara, Yoichi [Department of Applied Physics and Physico-Informatics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Yokohama 223-8522 (Japan); Shibuya, Taizo; Yasuoka, Kenji [Department of Mechanical Engineering, Faculty of Science and Technology, Keio University, Yokohama 223-8522 (Japan)

    2014-07-14

    Layered oxysulfide LaCu{sub 1?x}SO (x?=?0–0.03) was prepared to elucidate the effect of Cu off-stoichiometry on their electrical and thermal transport properties. Electrical resistivity drastically decreases down from ?10{sup 5} ?·cm to ?10{sup ?1} ?·cm as a result of Cu deficiency (x?=?0.01) at 300?K. Thermal conductivity of the samples at 300?K, which is dominated by lattice components, is estimated to be 2.3(3) Wm{sup ?1}K{sup ?1}. Stoichiometric LaCuSO has an optical band gap of 3.1?eV, while broad optical absorption at photon energies of approximately 2.1?eV was observed for Cu-deficient samples. Density functional theory calculation suggests that these broad absorption structures probably originate from the in-gap states generated by the sulfur vacancies created to compensate the charge imbalance due to Cu off-stoichiometry. These results clearly demonstrate that Cu deficiency plays a crucial role in determining the electrical transport properties of Cu-based p-type transparent semiconductors.

  9. Halftoning band gap of InAs/InP quantum dots using inductively coupled argon plasma-enhanced intermixing

    SciTech Connect (OSTI)

    Nie, D.; Mei, T.; Xu, C. D.; Dong, J. R.

    2006-09-25

    Inductively coupled argon plasma-enhanced intermixing of InAs/InP quantum dots grown on InP substrate is investigated. Intermixing is promoted by the near-surface defects generated by plasma exposure in annealing at a temperature of 600 deg. C for 30 s. The annealing results in a maximum differential band-gap blueshift of 106 nm but a thermal shift of only 10 nm. Band-gap halftones are obtained by controlling the amount of near-surface defects via wet chemical etching on the plasma-exposed InP cap layer. No degradation of quantum-dot crystal quality due to the process has been observed as evidenced by photoluminescence intensity.

  10. The change in dielectric constant, AC conductivity and optical band gaps of polymer electrolyte film: Gamma irradiation

    SciTech Connect (OSTI)

    Raghu, S., E-mail: dehu2010@gmail.com; Subramanya, K., E-mail: dehu2010@gmail.com; Sharanappa, C., E-mail: dehu2010@gmail.com; Mini, V., E-mail: dehu2010@gmail.com; Archana, K., E-mail: dehu2010@gmail.com; Sanjeev, Ganesh, E-mail: dehu2010@gmail.com; Devendrappa, H., E-mail: dehu2010@gmail.com [Dept. of Physics, Mangalore University, Mangalagangothri-574199 (India)

    2014-04-24

    The effects of gamma (?) irradiation on dielectric and optical properties of polymer electrolyte film were investigated. The dielectric constant and ac conductivity increases with ? dose. Also optical band gap decreased from 4.23 to 3.78ev after irradiation. A large dependence of the polymer properties on the irradiation dose was noticed. This suggests that there is a possibility of improving polymer electrolyte properties on gamma irradiation.

  11. Thermovoltaic semiconductor device including a plasma filter

    DOE Patents [OSTI]

    Baldasaro, Paul F. (Clifton Park, NY)

    1999-01-01

    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.

  12. Optimized dipole antennas on photonic band gap crystals S. D. Chenga)

    E-Print Network [OSTI]

    Ozbay, Ekmel

    efficiencies larger than antennas on other conventional dielectric substrates. © 1995 American Institute . A three-cylinder structure with diamond symmetry fabricated by drilling techniques first demonstrated3; an efficient directional antenna. Conventional integrated circuit antennas on a semi-infinite semiconductor

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

    E-Print Network [OSTI]

    Atwater, Harry

    an alternative InP- based approach for a triple junction solar cell formed by a combination of InAlAs 1.47 eV /In-free InxAl1-xAs alloyed layers were used to fabricate the single junction solar cell. PhotoluminescenceGaAs triple junction cells with efficiencies higher than 30% under 1-sun illumination.7 Additionally

  14. Synthesis, Structure, Thermoelectric Properties, and Band Gaps of Alkali Metal Containing Type I Clathrates: A8Ga8Si38 (A = K, Rb, Cs)

    E-Print Network [OSTI]

    Osterloh, Frank

    Synthesis, Structure, Thermoelectric Properties, and Band Gaps of Alkali Metal Containing Type I were consolidated by Spark Plasma Sintering (SPS) for thermoelectric property characterization. INTRODUCTION Thermoelectric materials have been intensively studied over the past decades as they can recycle

  15. Origin of the unusually large band-gap bowing and the breakdown of the band-edge distribution rule in the SnxGe1-x alloys

    E-Print Network [OSTI]

    Gong, Xingao

    , most semi- conductor alloys AxB1-x have a nonlinear dependence of its band gap Eg x as a function of the alloy composition x, and the variation is usually described by a parabolic function Eg alloy x = xEg A + 1 - x Eg B - bgx 1 - x , 1 where Eg A and Eg B are the band gaps of A and B at their respective

  16. Properties of Wide-Gap Chalcopyrite Semiconductors for Photovoltaic Applications: Final Report, 8 July 1998 -- 17 October 2001

    SciTech Connect (OSTI)

    Rockett, A.

    2003-07-01

    The objectives of this project were to obtain a fundamental understanding of wide-gap chalcopyrite semiconductors and photovoltaic devices. Information to be gathered included significant new fundamental materials data necessary for accurate modeling of single- and tandem-junction devices, basic materials science of wider-gap chalcopyrite semiconductors to be used in next-generation devices, and practical information on the operation of devices incorporating these materials. Deposition used a hybrid sputtering and evaporation method shown previously to produce high-quality epitaxial layers of Cu(In,Ga)Se2 (CIGS). Materials analysis was also provided to assist members of the National CIS Team, of which, through this contract, we were a member. Solar cells produced from resulting single-crystal epitaxial layers in collaboration with various members of the CIS Team were used to determine the factors limiting performance of the devices based on analysis of the results. Because epitaxial growth allows us to determine the surface orientation of our films specifically by choice of the substrate surface on which the film is grown, a major focus of the project concerned the nature of (110)-oriented CIGS films and the performance of solar cells produced from these films. We begin this summary with a description of the results for growth on (110) GaAs, which formed a basis for much of the work ultimately conducted under the program.

  17. Switching of the photonic band gap in three-dimensional film photonic crystals based on opal-VO{sub 2} composites in the 1.3-1.6 {mu}m spectral range

    SciTech Connect (OSTI)

    Pevtsov, A. B. Grudinkin, S. A.; Poddubny, A. N.; Kaplan, S. F.; Kurdyukov, D. A.; Golubev, V. G.

    2010-12-15

    The parameters of three-dimensional photonic crystals based on opal-VO{sub 2} composite films in the 1.3-1.6 {mu}m spectral range important for practical applications (Telecom standard) are numerically calculated. For opal pores, the range of filling factors is established (0.25-0.6) wherein the composite exhibits the properties of a three-dimensional insulator photonic crystal. On the basis of the opal-VO{sub 2} composites, three-dimensional photonic film crystals are synthesized with specified parameters that provide a maximum shift of the photonic band gap in the vicinity of the wavelength {approx}1.5 {mu}m ({approx}170 meV) at the semiconductor-metal transition in VO{sub 2}.

  18. Electronic Structures, Bonding Configurations, and Band-Gap-Opening Properties of Graphene Binding with Low-Concentration Fluorine

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

    Duan, Yuhua; Stinespring, Charter D.; Chorpening, Benjamin

    2015-06-18

    To better understand the effects of low-level fluorine in graphene-based sensors, first-principles density functional theory (DFT) with van der Waals dispersion interactions has been employed to investigate the structure and impact of fluorine defects on the electrical properties of single-layer graphene films. The results show that both graphite-2H and graphene have zero band gaps. When fluorine bonds to a carbon atom, the carbon atom is pulled slightly above the graphene plane, creating what is referred to as a CF defect. The lowest-binding energy state is found to correspond to two CF defects on nearest neighbor sites, with one fluorine abovemore »the carbon plane and the other below the plane. Overall this has the effect of buckling the graphene. The results further show that the addition of fluorine to graphene leads to the formation of an energy band (BF) near the Fermi level, contributed mainly from the 2p orbitals of fluorine with a small contribution from the porbitals of the carbon. Among the 11 binding configurations studied, our results show that only in two cases does the BF serve as a conduction band and open a band gap of 0.37 eV and 0.24 eV respectively. The binding energy decreases with decreasing fluorine concentration due to the interaction between neighboring fluorine atoms. The obtained results are useful for sensor development and nanoelectronics.« less

  19. Analysis of photonic band gaps in two-dimensional photonic crystals with rods covered by a thin interfacial layer

    SciTech Connect (OSTI)

    Trifonov, T.; Marsal, L.F.; Pallares, J.; Rodriguez, A.; Alcubilla, R.

    2004-11-15

    We investigate different aspects of the absolute photonic band gap (PBG) formation in two-dimensional photonic structures consisting of rods covered with a thin dielectric film. Specifically, triangular and honeycomb lattices in both complementary arrangements, i.e., air rods drilled in silicon matrix and silicon rods in air, are studied. We consider that the rods are formed of a dielectric core (silicon or air) surrounded by a cladding layer of silicon dioxide (SiO{sub 2}), silicon nitride (Si{sub 3}N{sub 4}), or germanium (Ge). Such photonic lattices present absolute photonic band gaps, and we study the evolution of these gaps as functions of the cladding material and thickness. Our results show that in the case of air rods in dielectric media the existence of dielectric cladding reduces the absolute gap width and may cause complete closure of the gap if thick layers are considered. For the case of dielectric rods in air, however, the existence of a cladding layer can be advantageous and larger absolute PBG's can be achieved.

  20. Lattice matched semiconductor growth on crystalline metallic substrates

    DOE Patents [OSTI]

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

    2013-11-05

    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.

  1. Conductivity and optical band gaps of polyethylene oxide doped with Li{sub 2}SO{sub 4} salt

    SciTech Connect (OSTI)

    Chapi, Sharanappa, E-mail: dehu2010@gmail.com; Raghu, S., E-mail: dehu2010@gmail.com; Subramanya, K., E-mail: dehu2010@gmail.com; Archana, K., E-mail: dehu2010@gmail.com; Mini, V., E-mail: dehu2010@gmail.com; Devendrappa, H., E-mail: dehu2010@gmail.com [Dept. of Physics, Mangalore University, Mangalagangothri-574199 (India)

    2014-04-24

    The conductivity and optical properties of Li{sub 2}SO{sub 4} doped polyethylene oxide (PEO) films were studied. The polymer electrolyte films are prepared using solution casting technique. The material phase change was confirmed by X-ray diffraction (XRD) technique. Optical absorption study was conducted using UV- Vis. Spectroscopy in the wavelength range 190–1100nm on pure and doped PEO films. The direct and indirect optical band gaps were found decreased from 5.81–4.51eV and 4.84–3.43eV respectively with increasing the Li{sub 2}SO{sub 4}. The conductivity found to increases with increasing the dopant concentration due to strong hopping mechanism at room temperature.

  2. 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)

    2014-01-07

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

  3. Hydrogen local vibrational modes in semiconductors

    SciTech Connect (OSTI)

    McCluskey, M D

    1997-06-01

    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.

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

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

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

    2011-12-15

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

  5. Systematic approach for simultaneously correcting the band-gap andp-dseparation errors of common cation III-V or II-VI binaries in density functional theory calculations within a local density approximation

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

    Wang, Jianwei; Zhang, Yong; Wang, Lin-Wang

    2015-07-31

    We propose a systematic approach that can empirically correct three major errors typically found in a density functional theory (DFT) calculation within the local density approximation (LDA) simultaneously for a set of common cation binary semiconductors, such as III-V compounds, (Ga or In)X with X = N,P,As,Sb, and II-VI compounds, (Zn or Cd)X, with X = O,S,Se,Te. By correcting (1) the binary band gaps at high-symmetry points , L, X, (2) the separation of p-and d-orbital-derived valence bands, and (3) conduction band effective masses to experimental values and doing so simultaneously for common cation binaries, the resulting DFT-LDA-based quasi-first-principles methodmore »can be used to predict the electronic structure of complex materials involving multiple binaries with comparable accuracy but much less computational cost than a GW level theory. This approach provides an efficient way to evaluate the electronic structures and other material properties of complex systems, much needed for material discovery and design.« less

  6. 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

    2011-08-01

    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.

  7. High-quality photonic crystals with a nearly complete band gap obtained by direct inversion of woodpile templates with titanium dioxide

    E-Print Network [OSTI]

    Marichy, Catherine; Froufe-Pérez, Luis S; Scheffold, Frank

    2015-01-01

    Photonic crystal materials are based on a periodic modulation of the dielectric constant on length scales comparable to the wavelength of light. These materials can exhibit photonic band gaps; frequency regions for which the propagation of electromagnetic radiation is forbidden due to the depletion of the density of states. In order to exhibit a full band gap, 3D PCs must present a threshold refractive index contrast that depends on the crystal structure. In the case of the so-called woodpile photonic crystals this threshold is comparably low, approximately 1.9 for the direct structure. Therefore direct or inverted woodpiles made of high refractive index materials like silicon, germanium or titanium dioxide are sought after. Here we show that, by combining multiphoton lithography and atomic layer deposition, we can achieve a direct inversion of polymer templates into TiO$_{2}$ based photonic crystals. The obtained structures show remarkable optical properties in the near-infrared region with almost perfect sp...

  8. Electron states in semiconductor quantum dots

    SciTech Connect (OSTI)

    Dhayal, Suman S.; Ramaniah, Lavanya M.; Ruda, Harry E.; Nair, Selvakumar V.

    2014-11-28

    In this work, the electronic structures of quantum dots (QDs) of nine direct band gap semiconductor materials belonging to the group II-VI and III-V families are investigated, within the empirical tight-binding framework, in the effective bond orbital model. This methodology is shown to accurately describe these systems, yielding, at the same time, qualitative insights into their electronic properties. Various features of the bulk band structure such as band-gaps, band curvature, and band widths around symmetry points affect the quantum confinement of electrons and holes. These effects are identified and quantified. A comparison with experimental data yields good agreement with the calculations. These theoretical results would help quantify the optical response of QDs of these materials and provide useful input for applications.

  9. 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)

    2013-10-15

    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.

  10. Synthesis of cadmium telluride quantum wires and the similarity of their band gaps to those of equidiameter cadmium telluride quantum dots

    SciTech Connect (OSTI)

    Wang, Lin-Wang; Sun, Jianwei; Wang, Lin-Wang; Buhro, William E.

    2008-07-11

    High-quality colloidal CdTe quantum wires having purposefully controlled diameters in the range of 5-11 nm are grown by the solution-liquid-solid (SLS) method, using Bi-nanoparticle catalysts, cadmium octadecylphosphonate and trioctylphosphine telluride as precursors, and a TOPO solvent. The wires adopt the wurtzite structure, and grow along the [002] direction (parallel to the c axis). The size dependence of the band gaps in the wires are determined from the absorption spectra, and compared to the experimental results for high-quality CdTe quantum dots. In contrast to the predictions of an effective-mass approximation, particle-in-a-box model, and previous experimental results from CdSe and InP dot-wire comparisons, the band gaps of CdTe dots and wires of like diameter are found to be experimentally indistinguishable. The present results are analyzed using density functional theory under the local-density approximation by implementing a charge-patching method. The higher-level theoretical analysis finds the general existence of a threshold diameter, above which dot and wire band gaps converge. The origin and magnitude of this threshold diameter is discussed.

  11. 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)

    2014-05-07

    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.

  12. PHYSICAL REVIEW B 91, 245202 (2015) Improved predictions of the physical properties of Zn-and Cd-based wide band-gap

    E-Print Network [OSTI]

    Curtarolo, Stefano

    2015-01-01

    Department of Physics, Central Michigan University, Mt. Pleasant, Michigan 48859, USA 2 Center for Materials scrutiny for their potential applications in spintronics, optoelectronics, and photovoltaics [1

  13. 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)

    2010-08-15

    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.

  14. Experimental and theoretical studies of band gap alignment in GaAs{sub 1?x}Bi{sub x}/GaAs quantum wells

    SciTech Connect (OSTI)

    Kudrawiec, R. Kopaczek, J.; Polak, M. P.; Scharoch, P.; Gladysiewicz, M.; Misiewicz, J.; Richards, R. D.; Bastiman, F.; David, J. P. R.

    2014-12-21

    Band gap alignment in GaAs{sub 1?x}Bi{sub x}/GaAs quantum wells (QWs) was studied experimentally by photoreflectance (PR) and theoretically, ab initio, within the density functional theory in which the supercell based calculations are combined with the alchemical mixing approximation applied to a single atom in a supercell. In PR spectra, the optical transitions related to the excited states in the QW (i.e., the transition between the second heavy-hole and the second electron subband) were clearly observed in addition to the ground state QW transition and the GaAs barrier transition. This observation is clear experimental evidence that this is a type I QW with a deep quantum confinement in the conduction and valence bands. From the comparison of PR data with calculations of optical transitions in GaAs{sub 1?x}Bi{sub x}/GaAs QW performed for various band gap alignments, the best agreement between experimental data and theoretical calculations has been found for the valence band offset of 52?±?5%. A very similar valence band offset was obtained from ab initio calculations. These calculations show that the incorporation of Bi atoms into GaAs host modifies both the conduction and the valence band. For GaAs{sub 1?x}Bi{sub x} with 0?band gap is parabolic and the reduction rates change from ?84 to ?53?meV per % Bi for lower and higher Bi concentrations, respectively. The calculated shifts of valence and conduction bands give the variation of valence (conduction) band offset between GaAs{sub 1?x}Bi{sub x} and GaAs in the range of ?60%–40% (?40%–60%), which is in good agreement with our conclusion derived from PR measurements.

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

    E-Print Network [OSTI]

    Dowling, Jonathan P.

    2007-01-01

    efficiency of solar cell devices without using concentrators. r 2007 Elsevier B.V. All rights reserved) solar energy conversion systems (or solar cells) are the most widely used power systems. HoweverSolar Energy Materials & Solar Cells 91 (2007) 1599­1610 Improving solar cell efficiency using

  16. 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)

    2013-10-14

    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.

  17. 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

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

    SciTech Connect (OSTI)

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

    2014-12-03

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

  19. Pseudo single crystal, direct-band-gap Ge{sub 0.89}Sn{sub 0.11} on amorphous dielectric layers towards monolithic 3D photonic integration

    SciTech Connect (OSTI)

    Li, Haofeng; Brouillet, Jeremy; Wang, Xiaoxin; Liu, Jifeng

    2014-11-17

    We demonstrate pseudo single crystal, direct-band-gap Ge{sub 0.89}Sn{sub 0.11} crystallized on amorphous layers at <450?°C towards 3D Si photonic integration. We developed two approaches to seed the lateral single crystal growth: (1) utilize the Gibbs-Thomson eutectic temperature depression at the tip of an amorphous GeSn nanotaper for selective nucleation; (2) laser-induced nucleation at one end of a GeSn strip. Either way, the crystallized Ge{sub 0.89}Sn{sub 0.11} is dominated by a single grain >18??m long that forms optoelectronically benign twin boundaries with others grains. These pseudo single crystal, direct-band-gap Ge{sub 0.89}Sn{sub 0.11} patterns are suitable for monolithic 3D integration of active photonic devices on Si.

  20. Scanning tunneling microscopy reveals LiMnAs is a room temperature anti-ferromagnetic semiconductor

    SciTech Connect (OSTI)

    Wijnheijmer, A. P.; Koenraad, P. M.; Marti, X.; Holy, V.; Cukr, M.; Novak, V.; Jungwirth, T.

    2012-03-12

    We performed scanning tunneling microscopy and spectroscopy on a LiMnAs(001) thin film epitaxially grown on an InAs(001) substrate by molecular beam epitaxy. While the in situ cleavage exposed only the InAs(110) non-polar planes, the cleavage continued into the LiMnAs thin layer across several facets. We combined both topography and current mappings to confirm that the facets correspond to LiMnAs. By spectroscopy we show that LiMnAs has a band gap. The band gap evidenced in this study, combined with the known Neel temperature well above room temperature, confirms that LiMnAs is a promising candidate for exploring the concepts of high temperature semiconductor spintronics based on antiferromagnets.

  1. Band-gap scaling of graphene nanohole superlattices Wei Liu,1,2 Z. F. Wang,2 Q. W. Shi,1 Jinlong Yang,1 and Feng Liu2

    E-Print Network [OSTI]

    Simons, Jack

    of potential applications.2 In addition to two- dimensional 2D graphene sheet, much attention has also been­5 and nanoholes antidots ,6­9 one-dimensional nanoribbons,10­16 as well as 2D graphene nanohole superlattices.6 confinement converting the semimetal graphene into semiconductors and the latter induces edge magnetism

  2. Refractive Indices of Semiconductors from Energy gaps

    E-Print Network [OSTI]

    Tripathy, S K

    2015-01-01

    An empirical relation based on energy gap and refractive index data has been proposed in the present study to calculate the refractive index of semiconductors. The proposed model is then applied to binary as well as ternary semiconductors for a wide range of energy gap. Using the relation, dielectric constants of some III-V group semiconductors are calculated. The calculated values for different group of binary semiconductors, alkali halides and ternary semiconductors fairly agree with other calculations and known values over a wide range of energy gap. The temperature variation of refractive index for some binary semiconductors have been calculated.

  3. Refractive Indices of Semiconductors from Energy gaps

    E-Print Network [OSTI]

    S. K. Tripathy

    2015-07-16

    An empirical relation based on energy gap and refractive index data has been proposed in the present study to calculate the refractive index of semiconductors. The proposed model is then applied to binary as well as ternary semiconductors for a wide range of energy gap. Using the relation, dielectric constants of some III-V group semiconductors are calculated. The calculated values for different group of binary semiconductors, alkali halides and ternary semiconductors fairly agree with other calculations and known values over a wide range of energy gap. The temperature variation of refractive index for some binary semiconductors have been calculated.

  4. Electrically pumped edge-emitting photonic bandgap semiconductor laser

    DOE Patents [OSTI]

    Lin, Shawn-Yu; Zubrzycki, Walter J.

    2004-01-06

    A highly efficient, electrically pumped edge-emitting semiconductor laser based on a one- or two-dimensional photonic bandgap (PBG) structure is described. The laser optical cavity is formed using a pair of PBG mirrors operating in the photonic band gap regime. Transverse confinement is achieved by surrounding an active semiconductor layer of high refractive index with lower-index cladding layers. The cladding layers can be electrically insulating in the passive PBG mirror and waveguide regions with a small conducting aperture for efficient channeling of the injection pump current into the active region. The active layer can comprise a quantum well structure. The quantum well structure can be relaxed in the passive regions to provide efficient extraction of laser light from the active region.

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

    SciTech Connect (OSTI)

    Zhou, Wenliang; Yang, Pingxiong Chu, Junhao; Deng, Hongmei

    2014-09-15

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

  6. 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

    2012-02-15

    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.

  7. 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)

    2012-01-25

    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.

  8. Low resistance ohmic contacts on wide band-gap GaN M. E. Lin, Z. Ma, F. Y. Huang, Z. F. Fan, L. H. Allen, and H. MorkoG

    E-Print Network [OSTI]

    Allen, Leslie H.

    -beam evaporation onto the GaN substrate, and then thermally annealed in a temperature range from 500 to 900 "C as high temperature/high power electrical devices, there still remains much more work to be done on GaN epilayers, Foresi et aL6 used Al and Au contacts with 575 "C anneal cycle. However, the specific

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

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

    Technologies Office Merit Review 2015: 88 Kilowatt Automotive Inverter with New 900 Volt Silicon Carbide MOSFET Technology Energy Storage & Power Electronics 2008 Peer Review -...

  10. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorking WithTelecentricNCubicthe FOIA? The FOIA,DepartmentWhoWhy: The

  11. Stretchable semiconductor elements and stretchable electrical circuits

    DOE Patents [OSTI]

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

    2009-07-07

    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.

  12. Optical properties of two-dimensional transition metal dichalcogenides

    E-Print Network [OSTI]

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

    2014-01-01

    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 ...

  13. Coexistence of different charge states in Ta-doped monoclinic HfO2: Theoretical and experimental approaches

    E-Print Network [OSTI]

    Svane, Axel Torstein

    and with the addition of small amounts of impurities, it has applications ranging from solid oxide fuel cell attention due to its potential technological applications. HfO2 is a wide-band- gap semiconductor

  14. Wide bandgap OPV polymers based on pyridinonedithiophene unit with efficiency >5%

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

    Schneider, Alexander M.; Lu, Luyao; Manley, Eric F.; Zheng, Tianyue; Sharapov, Valerii; Xu, Tao; Marks, Tobin J.; Chen, Lin X.; Yu, Luping

    2015-06-04

    We report the properties of a new series of wide band gap photovoltaic polymers based on the N-alkyl 2-pyridone dithiophene (PDT) unit. These polymers are effective bulk heterojunction solar cell materials when blended with phenyl-C71-butyric acid methyl ester (PC71BM). They achieve power conversion efficiencies (up to 5.33%) high for polymers having such large bandgaps, ca. 2.0 eV (optical) and 2.5 eV (electrochemical). As a result, grazing incidence wide-angle X-ray scattering (GIWAXS) reveals strong correlations between ?–? stacking distance and regularity, polymer backbone planarity, optical absorption maximum energy, and photovoltaic efficiency.

  15. Sandia Energy - Semiconductor Revolution

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

    Semiconductor Revolution Home Energy Research EFRCs Solid-State Lighting Science EFRC Semiconductor Revolution Semiconductor RevolutionTara Camacho-Lopez2015-05-14T14:32:12+00:00...

  16. CsSnI[subscript 3]: Semiconductor or Metal? High Electrical Conductivity and Strong Near-Infrared Photoluminescence from a Single Material. High Hole Mobility and Phase-Transitions

    SciTech Connect (OSTI)

    Chung, In; Song, Jung-Hwan; Im, Jino; Androulakis, John; Malliakas, Christos D.; Li, Hao; Freeman, Arthur J.; Kenney, John T.; Kanatzidis, Mercouri G. (NWU); (OmniPV)

    2012-10-29

    CsSnI{sub 3} is an unusual perovskite that undergoes complex displacive and reconstructive phase transitions and exhibits near-infrared emission at room temperature. Experimental and theoretical studies of CsSnI{sub 3} have been limited by the lack of detailed crystal structure characterization and chemical instability. Here we describe the synthesis of pure polymorphic crystals, the preparation of large crack-/bubble-free ingots, the refined single-crystal structures, and temperature-dependent charge transport and optical properties of CsSnI{sub 3}, coupled with ab initio first-principles density functional theory (DFT) calculations. In situ temperature-dependent single-crystal and synchrotron powder X-ray diffraction studies reveal the origin of polymorphous phase transitions of CsSnI{sub 3}. The black orthorhombic form of CsSnI{sub 3} demonstrates one of the largest volumetric thermal expansion coefficients for inorganic solids. Electrical conductivity, Hall effect, and thermopower measurements on it show p-type metallic behavior with low carrier density, despite the optical band gap of 1.3 eV. Hall effect measurements of the black orthorhombic perovskite phase of CsSnI{sub 3} indicate that it is a p-type direct band gap semiconductor with carrier concentration at room temperature of {approx} 10{sup 17} cm{sup -3} and a hole mobility of {approx} 585 cm{sup 2} V{sup -1} s{sup -1}. The hole mobility is one of the highest observed among p-type semiconductors with comparable band gaps. Its powders exhibit a strong room-temperature near-IR emission spectrum at 950 nm. Remarkably, the values of the electrical conductivity and photoluminescence intensity increase with heat treatment. The DFT calculations show that the screened-exchange local density approximation-derived band gap agrees well with the experimentally measured band gap. Calculations of the formation energy of defects strongly suggest that the electrical and light emission properties possibly result from Sn defects in the crystal structure, which arise intrinsically. Thus, although stoichiometric CsSnI{sub 3} is a semiconductor, the material is prone to intrinsic defects associated with Sn vacancies. This creates highly mobile holes which cause the materials to appear metallic.

  17. Lattice matched crystalline substrates for cubic nitride semiconductor growth

    DOE Patents [OSTI]

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

    2015-02-24

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

  18. 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...

  19. Wafer-fused semiconductor radiation detector

    DOE Patents [OSTI]

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

    2002-01-01

    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.

  20. Strain-and electric field-induced band gap modulation in nitride nanomembranes This article has been downloaded from IOPscience. Please scroll down to see the full text article.

    E-Print Network [OSTI]

    Pandey, Ravi

    or free-standing form with the mono-crystalline 2D-layer structures with thickness of 5­500 nm, and large of the bandgap is found to be significant whereas the strain-induced semiconductor-metal transition is predicted. Introduction Monolayer materials such as graphene have opened up the possibility of novel and cost

  1. Wide Bandgap Extrinsic Photoconductive Switches

    SciTech Connect (OSTI)

    Sullivan, J S

    2012-01-17

    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.

  2. Methods of producing free-standing semiconductors using sacrificial buffer layers and recyclable substrates

    DOE Patents [OSTI]

    Ptak, Aaron Joseph; Lin, Yong; Norman, Andrew; Alberi, Kirstin

    2015-05-26

    A method of producing semiconductor materials and devices that incorporate the semiconductor materials are provided. In particular, a method is provided of producing a semiconductor material, such as a III-V semiconductor, on a spinel substrate using a sacrificial buffer layer, and devices such as photovoltaic cells that incorporate the semiconductor materials. The sacrificial buffer material and semiconductor materials may be deposited using lattice-matching epitaxy or coincident site lattice-matching epitaxy, resulting in a close degree of lattice matching between the substrate material and deposited material for a wide variety of material compositions. The sacrificial buffer layer may be dissolved using an epitaxial liftoff technique in order to separate the semiconductor device from the spinel substrate, and the spinel substrate may be reused in the subsequent fabrication of other semiconductor devices. The low-defect density semiconductor materials produced using this method result in the enhanced performance of the semiconductor devices that incorporate the semiconductor materials.

  3. 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

    2014-03-04

    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.

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

    SciTech Connect (OSTI)

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

    2013-05-14

    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. (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)

    2011-07-19

    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. (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)

    2009-11-24

    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. 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)

    2011-02-15

    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.

  8. Unitary lens semiconductor device

    DOE Patents [OSTI]

    Lear, Kevin L. (Albuquerque, NM)

    1997-01-01

    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.

  9. 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)

    1990-10-23

    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.

  10. Semiconductor bridge (SCB) detonator

    DOE Patents [OSTI]

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

    1999-01-01

    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.

  11. Semiconductor bridge (SCB) detonator

    DOE Patents [OSTI]

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

    1999-01-19

    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.

  12. Electrical and Thermoelectrical Transport Properties of Graphene

    E-Print Network [OSTI]

    Wang, Deqi

    2011-01-01

    at the interface of semiconductors, graphene is open to anytwo. Graphene is thus a zero band gap semiconductor. FigureHowever, graphene is known as a zero band gap semiconductor,

  13. The picosecond dynamics of electron-hole pairs in graded and homogeneous CdS{sub x}Se{sub 1-x} semiconductors

    SciTech Connect (OSTI)

    Hane, J.K.

    1995-05-01

    Wavelength and composition dependence of the time-resolved luminescence were examined. Effects of macroscopic composition gradient and microscopic alloy disorder on e{sup {minus}}-h{sup +} pair dynamics were probed. Materials with both increasing and decreasing S content with distance from the surface were examined, where 0{le} {times} {le}1 over the full range. In these graded materials, the band gap energy also varies with position. The graded semiconductor luminescence shows strong wavelength dependence, showing diffusion in both band gap and concentration gradients. A bottleneck in the diffusion is attributed to localization occurring primarily in the materials with greatest alloy disorder, i.e. around CdS{sub 0.5}Se{sub 0.50}. Homogeneous materials were studied for x = 0, 0.25, 0.50, 0.75, 1; the time-resolved luminescence depends strongly on the composition. The mixed compositions have longer decay constants than CdS and CdSe. Observed lifetimes agree with a picture of localized states induced by the alloy disorder. For a given homogeneous crystal, no wavelength dependence of the time decays was observed. Picosecond luminescence upconversion spectroscopy was used to study further the dependence of the luminescence on composition. Large nonexponential character in the decay functions was observed in the alloys; this long time tail can be attributed to a broad distribution of relaxation times as modeled by the Kohlrausch exponential.

  14. Direct observation of a widely tunable bandgap in bilayer graphene

    E-Print Network [OSTI]

    Zettl, Alex

    . Most notably, the inversion symmetric AB-stacked bilayer graphene is a zero-bandgap semiconductor in the graphene FET device we are able to control independently the two key semiconductor parameters: electronicLETTERS Direct observation of a widely tunable bandgap in bilayer graphene Yuanbo Zhang1 *, Tsung

  15. Mismatched semiconductor nanowires: growth and characterization

    E-Print Network [OSTI]

    Yim, Joanne Wing Lan

    2011-01-01

    of Semiconductors: Physics and Materials Properties (system Material properties Zn-VI compound semiconductors (

  16. Advanced Electrical Characterization of Semiconductor Nanowires

    E-Print Network [OSTI]

    Khanal, Devesh Raj

    2010-01-01

    extracting materials properties from semiconductors is theimportant material properties of semiconductors are the free

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

    SciTech Connect (OSTI)

    Benecha, E. M.; Lombardi, E. B.

    2013-12-14

    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.

  18. Origin of spin gapless semiconductor behavior in CoFeCrGa. Theory and Experiment

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

    Bainsla, Lakhan; Mallick, A. I.; Raja, M. Manivel; Coelho, A. A.; Nigam, A. K.; Johnson, D. D.; Alam, Aftab; Suresh, K. G.

    2015-07-08

    Despite a plethora of materials suggested for spintronic applications, a new class of materials has emerged, namely spin gapless semiconductors (SGS), which offers potentially more advantageous properties than existing ones. These magnetic semiconductors exhibit a finite band gap for one spin channel and a closed gap for the other. Supported by electronic-structure calculations, we report evidence of SGS behavior in equiatomic quaternary CoFeCrGa, having a cubic Heusler (prototype LiMgPdSn) structure but exhibiting chemical disorder (DO3 structure). CoFeCrGa is found to transform from SGS to half-metallic phase under pressure, which is attributed to unique electronic-structure features. The saturation magnetization (MS) wasmore »obtained at 8K agrees with the Slater-Pauling rule and the Curie temperature (TC) is found to exceed 400K. Carrier concentration (up to 250K) and electrical conductivity are observed to be nearly temperature independent, prerequisites for SGS. The anomalous Hall coefficient is estimated to be 185S/cm at 5K. Considering the SGS properties and high TC, this material appears to be promising for spintronic applications.« less

  19. Origin of spin gapless semiconductor behavior in CoFeCrGa. Theory and Experiment

    SciTech Connect (OSTI)

    Bainsla, Lakhan; Mallick, A. I.; Raja, M. Manivel; Coelho, A. A.; Nigam, A. K.; Johnson, D. D.; Alam, Aftab; Suresh, K. G.

    2015-07-08

    Despite a plethora of materials suggested for spintronic applications, a new class of materials has emerged, namely spin gapless semiconductors (SGS), which offers potentially more advantageous properties than existing ones. These magnetic semiconductors exhibit a finite band gap for one spin channel and a closed gap for the other. Supported by electronic-structure calculations, we report evidence of SGS behavior in equiatomic quaternary CoFeCrGa, having a cubic Heusler (prototype LiMgPdSn) structure but exhibiting chemical disorder (DO3 structure). CoFeCrGa is found to transform from SGS to half-metallic phase under pressure, which is attributed to unique electronic-structure features. The saturation magnetization (MS) was obtained at 8K agrees with the Slater-Pauling rule and the Curie temperature (TC) is found to exceed 400K. Carrier concentration (up to 250K) and electrical conductivity are observed to be nearly temperature independent, prerequisites for SGS. The anomalous Hall coefficient is estimated to be 185S/cm at 5K. Considering the SGS properties and high TC, this material appears to be promising for spintronic applications.

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

    SciTech Connect (OSTI)

    Romaka, V. A.; Rogl, P.; Romaka, V. V.; Stadnyk, Yu. V.; Korzh, R. O.; Krayovskyy, V. Ya.; Horyn, A. M.

    2014-12-15

    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.

  1. Electrostatic screening by semiconductors 

    E-Print Network [OSTI]

    Krcmar, Maja

    1998-01-01

    distributions. We determine the sluice screening length for the screening of a charged surface defect, and the interaction energy between two charged surface defects. We find the spatial scales over which dielectric and metallic properties of the semiconductors...

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

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

    Articles DOE Announces Webinars on High Performance Space Conditioning Systems, Davis-Bacon Act Compliance, and More DOE Announces Webinars on Hydrogen Fueling Infrastructure...

  3. Wide Bandgap Semiconductors for Clean Energy Workshop Agenda

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

    losses than today's silicon based solid-state technologies. In the same way that the invention of the silicon chip 50 years ago led to the development of the modern computer and...

  4. Wide Bandgap Semiconductors for Clean Energy Workshop: Summary...

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

    in the closing session are provided below for each of the three focus areas: (1) Power Electronics for Electric Vehicles and Motor Drives (2) Power Electronics for...

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

    E-Print Network [OSTI]

    Nair, Sankar

    alternative green energy sources and the development of UV light sources for water purification and biological in our nation's future. Seeing that electrical energy is the fastest growing form of energy used a critical role the future of electronics. Unlike Si, these materials can have bandgaps that are tunable

  6. 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 on Delicious Rank EERE:Financing Tool Fits theCommittee Charter Operating Experience202-05-03 |Opinionand Fuel Cell

  7. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservationBio-Inspired SolarAbout /Two0Photos andSeminarsDesign » Design forWHY WIPP?Why is

  8. 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 on Delicious Rank EERE:Financing ToolInternationalReport FY2014 - Employers139 Weatherization Works| DepartmentElectronics

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

    Office of Environmental Management (EM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirley Ann Jackson About1996HowFOAShowingFuelWeatherize » Airare the EnergyEnergyEnergy

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

    Office of Environmental Management (EM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirley Ann Jackson About1996HowFOAShowingFuelWeatherize » Airare the

  11. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservation of Fe(II)Geothermal EnergyRenewableCompanies PilotTeaches NuclearScaled

  12. Direct Detection of sub-GeV Dark Matter with Semiconductor Targets

    E-Print Network [OSTI]

    Rouven Essig; Marivi Fernandez-Serra; Jeremy Mardon; Adrian Soto; Tomer Volansky; Tien-Tien Yu

    2015-09-04

    Dark matter in the sub-GeV mass range is a theoretically motivated but largely unexplored paradigm. Such light masses are out of reach for conventional nuclear recoil direct detection experiments, but may be detected through the small ionization signals caused by dark matter-electron scattering. Semiconductors are well-studied and are particularly promising target materials because their ${\\cal O}(1~\\rm{eV})$ band gaps allow for ionization signals from dark matter as light as a few hundred keV. Current direct detection technologies are being adapted for dark matter-electron scattering. In this paper, we provide the theoretical calculations for dark matter-electron scattering rate in semiconductors, overcoming several complications that stem from the many-body nature of the problem. We use density functional theory to numerically calculate the rates for dark matter-electron scattering in silicon and germanium, and estimate the sensitivity for upcoming experiments such as DAMIC and SuperCDMS. We find that the reach for these upcoming experiments has the potential to be orders of magnitude beyond current direct detection constraints and that sub-GeV dark matter has a sizable modulation signal. We also give the first direct detection limits on sub-GeV dark matter from its scattering off electrons in a semiconductor target (silicon) based on published results from DAMIC. We make available publicly our code, QEdark, with which we calculate our results. Our results can be used by experimental collaborations to calculate their own sensitivities based on their specific setup. The searches we propose will probe vast new regions of unexplored dark matter model and parameter space.

  13. Method of doping a semiconductor

    DOE Patents [OSTI]

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

    1983-01-01

    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.

  14. Chemistry at the Dirac Point of Graphene

    E-Print Network [OSTI]

    Sarkar, Santanu

    2013-01-01

    a consequence graphene is a zero-band-gap semiconductor, andGraphene is now on the International Roadmap for Semiconductorsgraphene is referred to as a zero band gap semiconductor,

  15. Optical and Excitonic Properties of Crystalline ZnS Nanowires: Toward Efficient Ultraviolet

    E-Print Network [OSTI]

    Xiong, Qihua

    semiconductor, has been most widely used for phosphor host,5 optical coating, and solar cells.6 Due to the wide luminescence. Despite their advantageous band gap, bulk or thin film ZnS materials have not been able, such as ZnS epilayers fabricated on GaAs by MBE8 and NWs grown by PLV15 or MBE.20 Although those reports

  16. Multiband semiconductor compositions for photovoltaic devices

    DOE Patents [OSTI]

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

    2010-05-04

    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%.

  17. Multiband semiconductor compositions for photovoltaic devices

    DOE Patents [OSTI]

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

    2012-03-06

    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%.

  18. Controlling the band gap energy of cluster-assembled materials

    E-Print Network [OSTI]

    2013-01-01

    Biochemistry and Materials Science & Engineering, UniversityBiochemistry and of Materials Science & Engineering at the

  19. Systematic study of photoluminescence upon band gap excitation...

    Office of Scientific and Technical Information (OSTI)

    sub 12Nasub 12TiOsub 3:Pr (RLa, Gd, Lu, and Y) were synthesized, and their structures, optical absorption and luminescent properties were investigated, and the...

  20. Systematic approach for simultaneously correcting the band-gap...

    Office of Scientific and Technical Information (OSTI)

    Number: Army W911NF-10-1-0524; AC02-05CH11231 Type: Publisher's Accepted Manuscript Journal Name: Physical Review. B, Condensed Matter and Materials Physics Additional Journal...

  1. A 250 GHz photonic band gap gyrotron amplifier

    E-Print Network [OSTI]

    Nanni, Emilio A. (Emilio Alessandro)

    2013-01-01

    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 ...

  2. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservation

  3. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effect PhotovoltaicsStructureInnovation Portal

  4. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effect PhotovoltaicsStructureInnovation PortalSubstrate-Induced

  5. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effect PhotovoltaicsStructureInnovation PortalSubstrate-InducedSubstrate-Induced

  6. Direct band gap electroluminescence from bulk germanium at room temperature

    Office of Scientific and Technical Information (OSTI)

    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 Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing BacteriaConnectlaser-solidSwitchgrass|FeTe0.55Se0.45 (Journal Article)using an

  7. Systematic study of photoluminescence upon band gap excitation in

    Office of Scientific and Technical Information (OSTI)

    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 Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail. (Conference)Feedback System inStatusandArticle)SystemSystem for(Technical

  8. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on dark matter ByMentor-ProtegeFromGasInnovation

  9. Amorphous semiconductor solar cell

    DOE Patents [OSTI]

    Dalal, Vikram L. (Newark, DE)

    1981-01-01

    A solar cell comprising a back electrical contact, amorphous silicon semiconductor base and junction layers and a top electrical contact includes in its manufacture the step of heat treating the physical junction between the base layer and junction layer to diffuse the dopant species at the physical junction into the base layer.

  10. 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.

    2007-09-21

    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.

  11. Optical and electronic properties of some binary semiconductors from energy gaps

    E-Print Network [OSTI]

    Sunil K. Tripathy; Anup Pattanaik

    2015-10-14

    II-VI and III-V tetrahedral semiconductors have significant potential for novel optoelectronic applications. In the present work, some of the optical and electronic properties of these groups of semiconductors have been studied using a recently proposed empirical relationship for refractive index from energy gap. The calculated values of these properties are also compared with those calculated from some well known relationships. From an analysis of the calculated electronic polarisability of these tetrahedral binary semiconductors from different formulations, we have proposed an empirical relation for its calculation. The predicted values of electronic polarisability of these semiconductors agree fairly well with the known values over a wide range of energy gap.

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

    SciTech Connect (OSTI)

    GLASER, EVAN

    2012-08-17

    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.

  13. Optical and electronic properties of some binary semiconductors from energy gaps

    E-Print Network [OSTI]

    Sunil K. Tripathy; Anup Pattanaik

    2015-08-23

    II-VI and III-V tetrahedral semiconductors have significant potential for novel optoelectronic applications. In the present work, some of the optical and electronic properties of these groups of semiconductors have been studied using a recently proposed empirical relationship for refractive index from energy gap. The calculated values of these properties are also compared with those calculated from some well known relationships. From an analysis of the calculated electronic polarisability of these tetrahedral binary semiconductors from different formulations, we have proposed an empirical relation for its calculation. The predicted values of electronic polarisability of these semiconductors agree fairly well with the known values over a wide range of energy gap.

  14. Optical and electronic properties of some binary semiconductors from energy gaps

    E-Print Network [OSTI]

    Tripathy, Sunil K

    2015-01-01

    II-VI and III-V tetrahedral semiconductors have significant potential for novel optoelectronic applications. In the present work, some of the optical and electronic properties of these groups of semiconductors have been studied using a recently proposed empirical relationship for refractive index from energy gap. The calculated values of these properties are also compared with those calculated from some well known relationships. From an analysis of the calculated electronic polarisability of these tetrahedral binary semiconductors from different formulations, we have proposed an empirical relation for its calculation. The predicted values of electronic polarisability of these semiconductors agree fairly well with the known values over a wide range of energy gap.

  15. 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. Maistruk, E. V.; Maryanchuk, P. D.

    2014-12-15

    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.

  16. 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)

    2002-01-01

    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.

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

    E-Print Network [OSTI]

    Bishop, Sarah R.

    2010-01-01

    and physical properties of semiconductor materials. Onematerials considered, Ge and III-V semiconductors, have favorable intrinsic properties

  18. Method of passivating semiconductor surfaces

    DOE Patents [OSTI]

    Wanlass, M.W.

    1990-06-19

    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. 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.

    1997-04-01

    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.

  20. PHYSICAL REVIEW B 88, 195422 (2013) Cavity-enhanced absorption and Fano resonances in graphene nanoribbons

    E-Print Network [OSTI]

    2013-01-01

    graphene, is its ability to behave as a semiconductor whose band gap can be tuned in a wide frequency rangePHYSICAL REVIEW B 88, 195422 (2013) Cavity-enhanced absorption and Fano resonances in graphene 2013) We analyze the absorption of a graphene nanoribbon placed into an optical cavity. We demonstrate

  1. Optical Cavity Effects in ZnO Nanowire Lasers and Waveguides Justin C. Johnson, Haoquan Yan,, Peidong Yang,*,, and Richard J. Saykally*,

    E-Print Network [OSTI]

    Cohen, Ronald C.

    fluence, with consideration of ZnO material properties and ultrafast excitation dynamics, demonstrates, California 94720-1460, and Materials Science DiVision, Lawrence Berkeley National Laboratory, Berkeley, California ReceiVed: February 25, 2003; In Final Form: April 25, 2003 Wide band gap semiconductor

  2. Growth of Aligned Single-Crystalline Rutile TiO2 Nanowires on Arbitrary Substrates and Their Application in Dye-Sensitized Solar Cells

    E-Print Network [OSTI]

    Zhou, Chongwu

    the anodization method has been used to grow TiO2 nanotubes,28 an oblique angle deposition method has beenGrowth of Aligned Single-Crystalline Rutile TiO2 Nanowires on Arbitrary Substrates TiO2 is a wide band gap semiconductor with important applications in photovoltaic cells

  3. Highly Mismatched Semiconductor Alloys with Extreme Compositions

    E-Print Network [OSTI]

    Levander, Alejandro X.

    2012-01-01

    A. , Properties of Advanced Semiconductor Materials GaN,Semiconductor alloying is a common method for tailoring material propertiesSemiconductor alloying is a common method for tailoring material properties

  4. Layered semiconductor neutron detectors

    DOE Patents [OSTI]

    Mao, Samuel S; Perry, Dale L

    2013-12-10

    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.

  5. A Spintronic Semiconductor with Selectable Charge Carriers

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

    A Spintronic Semiconductor with Selectable Charge Carriers A Spintronic Semiconductor with Selectable Charge Carriers Print Wednesday, 28 August 2013 00:00 Accentuating the...

  6. ELECTRON TRANSFER AT SENSITIZED SEMICONDUCTOR ELECTRODES

    E-Print Network [OSTI]

    Spitler, Mark T.

    2010-01-01

    Pleskov. , Y. , Electrochemistry of SemiconductorsjPlenum54 Semiconductor electrochemistry Experimental apparatus forSemiconductor electrochemistry is a complex intersec'tion of

  7. Thermal Conductivity of Polycrystalline Semiconductors and Ceramics

    E-Print Network [OSTI]

    Wang, Zhaojie

    2012-01-01

    F. , Properties of Advanced Semiconductor Materials GaN,materials In the semiconductor community, thermal conductivity is a very important property

  8. Scanned probe characterization of semiconductor nanostructures

    E-Print Network [OSTI]

    Law, James Jeremy MacDonald

    2009-01-01

    electronic properties on two semiconductor material systems.semiconductor materials system suffers from perturbations in local electronic structure due to crystallographic defects. Understanding the electronic properties

  9. HAPPY NEW YEAR! Semiconductor Spintronics

    E-Print Network [OSTI]

    Nikolic, Branislav K.

    HAPPY NEW YEAR! #12;Semiconductor Spintronics Niu Burkov Culcer Nunez Nomura Yao Sinova Sinitsyn Dietl Koenig Lin Timm Jungwirth Lee Fernandez-Rossier U. Texas at Austin 2005 Taiwan Spintronics Workshop #12;Spintronics Toolbag Ferromagnetic Semiconductors (Ga,Mn)As .... others Coupled Spin Charge

  10. Variable temperature semiconductor film deposition

    DOE Patents [OSTI]

    Li, X.; Sheldon, P.

    1998-01-27

    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.

  11. Process for producing chalcogenide semiconductors

    DOE Patents [OSTI]

    Noufi, R.; Chen, Y.W.

    1985-04-30

    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.

  12. Electrical Transport in Carbon Nanotubes and Graphene

    E-Print Network [OSTI]

    Liu, Gang

    2010-01-01

    2001), graphene (Miao et al. , 2007), and semiconductorzero. So graphene is zero band gap semiconductor. At the lowgraphene may potentially replace silicon in the semiconductor

  13. Electronic, Vibrational and Thermoelectric Properties of Two-Dimensional Materials

    E-Print Network [OSTI]

    Wickramaratne, Darshana

    2015-01-01

    metal dichalcogenide semiconductor: Materials properties andproperties of semiconducting materials. The most well known problem is the band gaps of semiconductors and

  14. 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)

    2010-07-15

    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.

  15. Semiconductor radiation detector

    DOE Patents [OSTI]

    Bell, Zane W. (Oak Ridge, TN); Burger, Arnold (Knoxville, TN)

    2010-03-30

    A semiconductor detector for ionizing electromagnetic radiation, neutrons, and energetic charged particles. The detecting element is comprised of a compound having the composition I-III-VI.sub.2 or II-IV-V.sub.2 where the "I" component is from column 1A or 1B of the periodic table, the "II" component is from column 2B, the "III" component is from column 3A, the "IV" component is from column 4A, the "V" component is from column 5A, and the "VI" component is from column 6A. The detecting element detects ionizing radiation by generating a signal proportional to the energy deposited in the element, and detects neutrons by virtue of the ionizing radiation emitted by one or more of the constituent materials subsequent to capture. The detector may contain more than one neutron-sensitive component.

  16. The electronic structure changes and the origin of the enhanced optical properties in N-doped anatase TiO{sub 2}—A theoretical revisit

    SciTech Connect (OSTI)

    Kuo, Chin-Lung, E-mail: chinlung@ntu.edu.tw; Chen, Wei-Guang; Chen, Tzu-Ying [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

    2014-09-07

    We have investigated the electronic structure changes and the origin of the enhanced optical properties of N-doped anatase TiO{sub 2} using first-principles density-functional theory calculations. To determine the band gap variations induced by N-doping, we developed a new approach to locate the effective valence band maximum (VBM) by characterizing the degree of localization of the N-induced states in the band structures of various N-doped TiO{sub 2} systems. Our calculations show that the band gap variations are largely affected by the local bonding structures and doping concentration of the substitutional N atoms. As the N content is up to certain level, some local bonding structures can indeed cause band gap reduction due to the formation of band-like delocalized states above the VBM of TiO{sub 2}, while other local bonding configurations may simply form localized impurity states in the band gap. Accordingly, the N-induced localized and delocalized electronic states can exist simultaneously to contribute to the enhanced optical properties of anatase TiO{sub 2}. Our computational approach also provides a new way to investigate the band gap engineering of other wide band gap semiconductor material systems.

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

    DOE Patents [OSTI]

    Sopori, Bhushan; Rangappan, Anikara

    2014-11-25

    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.

  18. Life-cycle Assessment of Semiconductors

    E-Print Network [OSTI]

    Boyd, Sarah B.

    2009-01-01

    semiconductor processing materials are closely held intellectual property. Chemical textbooks and handbooks

  19. Semiconductor Nanocrystals for Biological Imaging

    SciTech Connect (OSTI)

    Fu, Aihua; Gu, Weiwei; Larabell, Carolyn; Alivisatos, A. Paul

    2005-06-28

    Conventional organic fluorophores suffer from poor photo stability, narrow absorption spectra and broad emission feature. Semiconductor nanocrystals, on the other hand, are highly photo-stable with broad absorption spectra and narrow size-tunable emission spectra. Recent advances in the synthesis of these materials have resulted in bright, sensitive, extremely photo-stable and biocompatible semiconductor fluorophores. Commercial availability facilitates their application in a variety of unprecedented biological experiments, including multiplexed cellular imaging, long-term in vitro and in vivo labeling, deep tissue structure mapping and single particle investigation of dynamic cellular processes. Semiconductor nanocrystals are one of the first examples of nanotechnology enabling a new class of biomedical applications.

  20. Design and Synthesis of Novel Diluted Magnetic Semiconductors...

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

    Design and Synthesis of Novel Diluted Magnetic Semiconductors Diluted magnetic semiconductors (DMSs) are semiconductors doped with small amounts of magnetic active transition...

  1. Growth and Characterization of Semiconductor Nanostructures for Nanoelectronics

    E-Print Network [OSTI]

    Zhong, Jiebin

    2011-01-01

    of semiconductors. Physics and materials properties.of semiconductors. Physics and materials properties, 1996.properties [19, 46-52], compared with bulk materials. In general, when semiconductor

  2. 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

    2014-05-20

    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.

  3. 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)

    2012-07-10

    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.

  4. Impurity gettering in semiconductors

    DOE Patents [OSTI]

    Sopori, B.L.

    1995-06-20

    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.

  5. Ultrafast laser-induced changes in optical properties of semiconductors

    SciTech Connect (OSTI)

    Chirila, C. C.; Lim, Freda C. H.; Gavaza, M. G. [Institute of High Performance Computing, 1 Fusionopolis Way, 16-16 Connexis, 138632 (Singapore)

    2012-04-01

    We study the effect of laser radiation on optical properties of semiconductors of industrial interest. The material is pumped with a laser of chosen central frequency, for which the absorption is maximal, thus inducing electron dynamics, which modifies the optical properties. By using an improved theoretical model, we study ultrafast dynamic changes in the refraction index and reflectivity corresponding to a wide frequency-interval of probing radiation and identify that interval where these optical changes are most significant.

  6. Method of preparing nitrogen containing semiconductor material

    DOE Patents [OSTI]

    Barber, Greg D.; Kurtz, Sarah R.

    2004-09-07

    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.

  7. Correlated exciton dynamics in semiconductor nanostructures

    E-Print Network [OSTI]

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

    2013-01-01

    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 ...

  8. Research on defects and transport in amorphous-silicon-based semiconductors. Final subcontract report, 20 February 1991--19 April 1994

    SciTech Connect (OSTI)

    Schiff, E.A.; Antoniadis, H.; Gu, Q.; Lee, J.K.; Wang, Q.; Zafar, S. [Syracuse Univ., NY (United States)

    1994-09-01

    This report describes work on three individual tasks as follows. (1) Electron and hole drift measurements in a-Si{sub 1-x}Ge{sub x}:H and a-Si{sub 1-x}C{sub x}:H p-i-n solar cells. Multijunction solar cells incorporating modified band gap a-Si:H in a triple-junction structure are generally viewed as the most promising avenue for achieving an amorphous silicon-based solar call with 15% stabilized conversion efficiency. The specific objective of this task was to document the mobilities and deep-trapping mobility-lifetime products for electrons and holes in a-Si{sub 1-x}Ge{sub x}:H and a-Si{sub 1-x}C{sub x}:H alloys materials. (2) Electroabsorption measurements and built-in potential (V{sub bi}) in solar cells. V{sub bi} in a p-i-n solar call may be limiting the open-circuit voltage (V{sub oc}) in wide-band-gap cells (E{sub g} > 1.8 eV) currently under investigation as the top cell for 15% triple junction devices. The research addressed four issues that need to be resolved before the method can yield an error less than 0.1 V for V{sub bi}. The details are presented in this report. (3) Defect relaxation and Shockley-Read kinetics in a-Si:H. Quantitative modeling of solar cells is usually based on Shockley-Read kinetics.`` An important assumption of this approach is that the rate of emission of a photocarrier trapped on a defect is independent of quasi-Fermi level location.

  9. Semiconductor electrode with improved photostability characteristics

    DOE Patents [OSTI]

    Frank, A.J.

    1985-02-19

    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.

  10. Semiconductor nanocrystal-based phagokinetic tracking

    DOE Patents [OSTI]

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

    2014-11-18

    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.

  11. Semiconductor assisted metal deposition for nanolithography applications

    DOE Patents [OSTI]

    Rajh, Tijana (Naperville, IL); Meshkov, Natalia (Downers Grove, IL); Nedelijkovic, Jovan M. (Belgrade, YU); Skubal, Laura R. (West Brooklyn, IL); Tiede, David M. (Elmhurst, IL); Thurnauer, Marion (Downers Grove, IL)

    2002-01-01

    An article of manufacture and method of forming nanoparticle sized material components. A semiconductor oxide substrate includes nanoparticles of semiconductor oxide. A modifier is deposited onto the nanoparticles, and a source of metal ions are deposited in association with the semiconductor and the modifier, the modifier enabling electronic hole scavenging and chelation of the metal ions. The metal ions and modifier are illuminated to cause reduction of the metal ions to metal onto the semiconductor nanoparticles.

  12. e! Science News Semiconductor manufacturing technique holds

    E-Print Network [OSTI]

    Rogers, John A.

    e! Science News Semiconductor manufacturing technique holds promise for solar energy PublishedSemiconductor manufacturing technique holds promise for solar energy | e! Science News 5/26/2010http semiconductor manufacturing method pioneered at the University of Illinois, the future of solar energy just got

  13. Mechanical scriber for semiconductor devices

    DOE Patents [OSTI]

    Lin, Peter T. (East Brunswick, NJ)

    1985-01-01

    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.

  14. Mechanical scriber for semiconductor devices

    DOE Patents [OSTI]

    Lin, P.T.

    1985-03-05

    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.

  15. High quality HfO{sub 2}/p-GaSb(001) metal-oxide-semiconductor capacitors with 0.8?nm equivalent oxide thickness

    SciTech Connect (OSTI)

    Barth, Michael; Datta, Suman; Bruce Rayner, G.; McDonnell, Stephen; Wallace, Robert M.; Bennett, Brian R.; Engel-Herbert, Roman

    2014-12-01

    We investigate in-situ cleaning of GaSb surfaces and its effect on the electrical performance of p-type GaSb metal-oxide-semiconductor capacitor (MOSCAP) using a remote hydrogen plasma. Ultrathin HfO{sub 2} films grown by atomic layer deposition were used as a high permittivity gate dielectric. Compared to conventional ex-situ chemical cleaning methods, the in-situ GaSb surface treatment resulted in a drastic improvement in the impedance characteristics of the MOSCAPs, directly evidencing a much lower interface trap density and enhanced Fermi level movement efficiency. We demonstrate that by using a combination of ex-situ and in-situ surface cleaning steps, aggressively scaled HfO{sub 2}/p-GaSb MOSCAP structures with a low equivalent oxide thickness of 0.8?nm and efficient gate modulation of the surface potential are achieved, allowing to push the Fermi level far away from the valence band edge high up into the band gap of GaSb.

  16. Controlled growth of semiconductor crystals

    DOE Patents [OSTI]

    Bourret-Courchesne, E.D.

    1992-07-21

    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.

  17. Controlled growth of semiconductor crystals

    DOE Patents [OSTI]

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

    1992-01-01

    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.

  18. Back-side readout semiconductor photomultiplier

    DOE Patents [OSTI]

    Choong, Woon-Seng; Holland, Stephen E

    2014-05-20

    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.

  19. Semiconductor Quantum Rods as Single Molecule FluorescentBiological Labels

    SciTech Connect (OSTI)

    Fu, Aihua; Gu, Weiwei; Boussert, Benjamine; Koski, Kristie; Gerion, Daniele; Manna, Liberato; Le Gros, Mark; Larabell, Carolyn; Alivisatos, A. Paul

    2006-05-29

    In recent years, semiconductor quantum dots have beenapplied with great advantage in a wide range of biological imagingapplications. The continuing developments in the synthesis of nanoscalematerials and specifically in the area of colloidal semiconductornanocrystals have created an opportunity to generate a next generation ofbiological labels with complementary or in some cases enhanced propertiescompared to colloidal quantum dots. In this paper, we report thedevelopment of rod shaped semiconductor nanocrystals (quantum rods) asnew fluorescent biological labels. We have engineered biocompatiblequantum rods by surface silanization and have applied them fornon-specific cell tracking as well as specific cellular targeting. Theproperties of quantum rods as demonstrated here are enhanced sensitivityand greater resistance for degradation as compared to quantum dots.Quantum rods have many potential applications as biological labels insituations where their properties offer advantages over quantumdots.

  20. Wide Blue Sky

    E-Print Network [OSTI]

    Collins, Caroline Imani

    2011-01-01

    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

  1. Island Wide Management Corporation

    Office of Legacy Management (LM)

    9 1986 Island Wide Management Corporation 3000 Marcus Avenue Lake Success, New York 11042 Dear Sir or Madam: I am sending you this letter and the enclosed information as you have...

  2. Metal contacts on ZnSe and GaN

    SciTech Connect (OSTI)

    Duxstad, K J [Univ. of California, Berkeley, CA (United States). Materials Science and Mineral Engineering

    1997-05-01

    Recently, considerable interest has been focused on the development of blue light emitting materials and devices. The focus has been on GaN and ZnSe, direct band gap semiconductors with bands gaps of 3.4 and 2.6 eV, respectively. To have efficient, reliable devices it is necessary to have thermally and electrically stable Ohmic contacts. This requires knowledge of the metal-semiconductor reaction behavior. To date few studies have investigated this behavior. Much information has accumulated over the years on the behavior of metals on Si and GaAs. This thesis provides new knowledge for the more ionic wide band gap semiconductors. The initial reaction temperatures, first phases formed, and phase stability of Pt, Pd, and Ni on both semiconductors were investigated. The reactions of these metals on ZnSe and GaN are discussed in detail and correlated with predicted behavior. In addition, comparisons are made between these highly ionic semiconductors and Si and GaAs. The trends observed here should also be applicable to other II-VI and III-Nitride semiconductor systems, while the information on phase formation and stability should be useful in the development of contacts for ZnSe and GaN devices.

  3. Compound semiconductor optical waveguide switch

    DOE Patents [OSTI]

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

    2003-06-10

    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.

  4. Band structure properties of (BGa)P semiconductors for lattice matched integration on (001) silicon

    SciTech Connect (OSTI)

    Hossain, Nadir; Sweeney, Stephen [Advanced Technology Institute and Department of Physics, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Hosea, Jeff [Advanced Technology Institute and Department of Physics, University of Surrey, Guildford, Surrey GU2 7XH, UK and Ibnu Sina Institute for Fundamental Science Studies, Universiti Teknologi Malaysia, Johor Bahru 81310 (Malaysia); Liebich, Sven; Zimprich, Martin; Volz, Kerstin; Stolz, Wolfgang [Material Sciences Center and Faculty of Physics, Philipps-University, 35032 Marburg (Germany); Kunert, Bernerdette [NAsP III/V GmbH, Am Knechtacker 19, 35041 Marburg (Germany)

    2013-12-04

    We report the band structure properties of (BGa)P layers grown on silicon substrate using metal-organic vapour-phase epitaxy. Using surface photo-voltage spectroscopy we find that both the direct and indirect band gaps of (BGa)P alloys (strained and unstrained) decrease with Boron content. Our experimental results suggest that the band gap of (BGa)P layers up to 6% Boron is large and suitable to be used as cladding and contact layers in GaP-based quantum well heterostructures on silicon substrates.

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

    E-Print Network [OSTI]

    Wu, Zhigang

    2014-01-01

    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

  6. Optical devices featuring textured semiconductor layers

    DOE Patents [OSTI]

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

    2011-10-11

    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.

  7. Optical devices featuring textured semiconductor layers

    DOE Patents [OSTI]

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

    2012-08-07

    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.

  8. 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...

  9. A Spintronic Semiconductor with Selectable Charge Carriers

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

    A Spintronic Semiconductor with Selectable Charge Carriers Print Accentuating the Positive (or the Negative) Spintronics-a type of electronics that makes use of electron spin as...

  10. A Spintronic Semiconductor with Selectable Charge Carriers

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

    using semiconductor materials like silicon and germanium that have the requisite properties to perform logical operations with both electrons (negative n-type charge carriers)...

  11. Scattering Properties of nanostructures : applications to photovoltaics

    E-Print Network [OSTI]

    Derkacs, Daniel

    2009-01-01

    way to enhance solar energy conversion in solar cells thatlimit of solar energy conversion in a semiconductor. Theefficiency of solar energy conversion versus the band gap

  12. Oh the Places You'll Go, with Graphene: A Chemists Exploration of Two Dimensions

    E-Print Network [OSTI]

    Wassei, Jonathan Khalil

    2013-01-01

    Biased Bilayer Graphene: Semiconductor with a Gap Tunable byA role for graphene in silicon- based semiconductor devices.pristine graphene is a zero-band gap semiconductor with an

  13. Optic probe for semiconductor characterization

    DOE Patents [OSTI]

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

    2008-09-02

    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).

  14. Yunnan Semiconductor | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIX ECoop IncIowa (UtilityMichigan) Jump to:SanmingYunlongGreenenergy CoEnergySemiconductor

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

    Open Energy Info (EERE)

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

  16. PROTECTIVE SURFACE COATINGS ON SEMICONDUCTOR NUCLEAR RADIATION DETECTORS

    E-Print Network [OSTI]

    Hansen, W.L.

    2010-01-01

    Science PROTECTIVE SURFACE COATINGS ON SEMICONDUCTOR NUCLEARF PROTECTIVE SURFACE COATINGS ON SEMICONDUCTOR NUCLEARchannel for one particular coating is unrelated to the

  17. 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...

  18. PROTECTIVE SURFACE COATINGS ON SEMICONDUCTOR NUCLEAR RADIATION DETECTORS

    E-Print Network [OSTI]

    Hansen, W.L.

    2010-01-01

    SEMICONDUCTOR NUCLEAR RADIATION DETECTORS W. L. Hansen, E.SEMICONDUCTOR NUCLEAR RADIATION DETECTORS* W. L. Hansen, E.suita­ bility for radiation detectors. Collimated gamma-ray

  19. 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...

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

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

    Metal Oxide Semiconductor Nanoparticles Open the Door to New Medical Innovations Technology available for licensing: novel nanometer-sized metal oxide semiconductors that allow...

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

    E-Print Network [OSTI]

    Zeng, Dekong

    2012-01-01

    maps in semiconductor manufacturing. ” Pattern Recognit.Third ISMI Symposium on Manufacturing Effectiveness. Austin,thickness in semiconductor manufacturing. In Proceedings of

  2. Semiconductor-nanocrystal/conjugated polymer thin films (Patent...

    Office of Scientific and Technical Information (OSTI)

    Semiconductor-nanocrystalconjugated polymer thin films Citation Details In-Document Search Title: Semiconductor-nanocrystalconjugated polymer thin films You are accessing a...

  3. ENERGY TRANSPORT IN SEMICONDUCTOR DEVICES ANSGAR JUNGEL

    E-Print Network [OSTI]

    Jüngel, Ansgar

    ENERGY TRANSPORT IN SEMICONDUCTOR DEVICES ANSGAR J¨UNGEL Abstract. The modeling, analysis, and numerical approximation of energy-transport models for semiconductor devices is reviewed. The derivation-dependent energy-transport equations with physical transport coefficients. The discretization of the stationary

  4. Semiclassical Transport Models for Semiconductor Spintronics

    E-Print Network [OSTI]

    Saikin, Semion

    Semiclassical Transport Models for Semiconductor Spintronics Yuriy V. Pershin,1,2 Semion Saikin1 spintronic device modeling. These include drift-diffusion models, kinetic transport equations and Monte Carlo in semiconductor structures have moved the state of the art closer to the realiza- tion of novel spintronic devices

  5. Semiclassical Transport Models for Semiconductor Spintronics

    E-Print Network [OSTI]

    Privman, Vladimir

    Semiclassical Transport Models for Semiconductor Spintronics Yuriy V. Pershin,1,2 Semion Saikin1 spintronic device modeling. These include drift-diffusion models, kinetic transport equations and Monte Carlo in semiconductor structures have moved the state of the art closer to the realization of novel spintronic devices

  6. Preparation of a semiconductor thin film

    DOE Patents [OSTI]

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

    1998-01-27

    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.

  7. COLLOIDAL SEMICONDUCTOR NANOCRYSTALS BASED SOLAR CELLS

    E-Print Network [OSTI]

    Tessler, Nir

    COLLOIDAL SEMICONDUCTOR NANOCRYSTALS BASED SOLAR CELLS Nir Yaacobi-Gross #12;COLLOIDAL SEMICONDUCTOR NANOCRYSTALS BASED SOLAR CELLS Research Thesis Submitted in Partial Fulfilment of the Requirements type II bulk homojunctions in near IR active all nanocrystals solar cells. Submitted to Adv Mater. 2011

  8. Semiconductor Nanowire Optical Antenna Solar Absorbers

    E-Print Network [OSTI]

    Fan, Shanhui

    cost reductions in the manufacturing of solar mod- ules.1 Moreover, it is essential to identify newSemiconductor Nanowire Optical Antenna Solar Absorbers Linyou Cao, Pengyu Fan, Alok P. Vasudev the absorption for solar radiation by 25% while utilizing less than half of the semiconductor material (250

  9. 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

    2013-11-19

    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).

  10. 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)

    1998-01-01

    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.

  11. EXCITONIC EIGENSTATES OF DISORDERED SEMICONDUCTOR QUANTUM WIRES

    E-Print Network [OSTI]

    to be symmetric, continuous, and coercive. The disorder of the wire is modelled by adding a potential in the Hamil.meier@uni-paderborn.de http://www.global-sci.com/ Global Science Preprint #12;2 1 Introduction Semiconductors of semiconductors are exploited in solar cells, light emitting diodes, and lasers, and, furthermore, future

  12. Semiconductor switch geometry with electric field shaping

    DOE Patents [OSTI]

    Booth, R.; Pocha, M.D.

    1994-08-23

    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.

  13. Semiconductor switch geometry with electric field shaping

    DOE Patents [OSTI]

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

    1994-01-01

    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.

  14. Field effect transistors with layered two-dimensional SnS22xSex conduction channels: Effects of selenium substitution

    E-Print Network [OSTI]

    Peng, Haibing

    ://dx.doi.org/10.1063/1.4819072] Sustaining Moore's Law beyond silicon-based elec- tronic devices has drawn ever for wide range of applications in areas like field effect devices,10,11 memory devices,12 and energy storage.13,14 Among this class of mate- rials, SnS2, a semiconductor with a band gap of 2.1 e

  15. 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)

    2014-04-21

    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.

  16. Phosphorous doping a semiconductor particle

    DOE Patents [OSTI]

    Stevens, Gary Don (18912 Ravenglen Ct, Dallas, TX 75287); Reynolds, Jeffrey Scott (703 Horizon, Murphy, TX 75094)

    1999-07-20

    A method (10) of phosphorus doping a semiconductor particle using ammonium phosphate. A p-doped silicon sphere is mixed with a diluted solution of ammonium phosphate having a predetermined concentration. These spheres are dried (16, 18), with the phosphorus then being diffused (20) into the sphere to create either a shallow or deep p-n junction. A good PSG glass layer is formed on the surface of the sphere during the diffusion process. A subsequent segregation anneal process is utilized to strip metal impurities from near the p-n junction into the glass layer. A subsequent HF strip procedure is then utilized to removed the PSG layer. Ammonium phosphate is not a restricted chemical, is inexpensive, and does not pose any special shipping, handling, or disposal requirement.

  17. Phosphorus doping a semiconductor particle

    DOE Patents [OSTI]

    Stevens, G.D.; Reynolds, J.S.

    1999-07-20

    A method of phosphorus doping a semiconductor particle using ammonium phosphate is disclosed. A p-doped silicon sphere is mixed with a diluted solution of ammonium phosphate having a predetermined concentration. These spheres are dried with the phosphorus then being diffused into the sphere to create either a shallow or deep p-n junction. A good PSG glass layer is formed on the surface of the sphere during the diffusion process. A subsequent segregation anneal process is utilized to strip metal impurities from near the p-n junction into the glass layer. A subsequent HF strip procedure is then utilized to removed the PSG layer. Ammonium phosphate is not a restricted chemical, is inexpensive, and does not pose any special shipping, handling, or disposal requirement. 1 fig.

  18. Heating device for semiconductor wafers

    DOE Patents [OSTI]

    Vosen, Steven R. (Berkeley, CA)

    1999-01-01

    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.

  19. Heating device for semiconductor wafers

    DOE Patents [OSTI]

    Vosen, S.R.

    1999-07-27

    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.

  20. 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

    2014-03-15

    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.).

  1. Nitride semiconductor Surface and interface characterization and device design

    E-Print Network [OSTI]

    Zhang, Hongtao

    2006-01-01

    piezoelectric polarization effects in nitride heterostructures," in III-V Nitride Semiconductors: Applications

  2. 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

  3. Electronegativity estimation of electronic polarizabilities of semiconductors

    SciTech Connect (OSTI)

    Li, Keyan [State Key Laboratory of Fine Chemicals, Department of Materials Science and Chemical Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian 116012 (China)] [State Key Laboratory of Fine Chemicals, Department of Materials Science and Chemical Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian 116012 (China); Xue, Dongfeng, E-mail: dfxue@chem.dlut.edu.cn [State Key Laboratory of Fine Chemicals, Department of Materials Science and Chemical Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian 116012 (China)] [State Key Laboratory of Fine Chemicals, Department of Materials Science and Chemical Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian 116012 (China)

    2010-03-15

    On the basis of the viewpoint of structure-property relationship in solid state matters, we proposed some useful relations to quantitatively calculate the electronic polarizabilities of binary and ternary chalcopyrite semiconductors, by using electronegativity and principal quantum number. The calculated electronic polarizabilities are in good agreement with reported values in the literature. Both electronegativity and principal quantum number can effectively reflect the detailed chemical bonding behaviors of constituent atoms in these semiconductors, which determines the magnitude of their electronic polarizabilities. The present work provides a useful guide to compositionally design novel semiconductor materials, and further explore advanced electro-optic devices.

  4. 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)

    2011-08-23

    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.

  5. Surface phonons of III-V semiconductors 

    E-Print Network [OSTI]

    Das, Pradip Kumar

    1994-01-01

    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...

  6. Electrical Usage Characterization of Semiconductor Processing Tools 

    E-Print Network [OSTI]

    Hinson, S. R.

    2000-01-01

    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...

  7. Spin injection and manipulation in organic semiconductors

    E-Print Network [OSTI]

    Venkataraman, Karthik (Karthik Raman)

    2011-01-01

    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 ...

  8. 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 ...

  9. 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

  10. A Markovian analysis of semiconductor manufacturing processes 

    E-Print Network [OSTI]

    Schultz, Kent Eugene

    1991-01-01

    CHAPTER I INTRODUCTION Manufacturing process control is necessary to achieve and maintain high quality man- ufactured product. Semiconductor fabrication process control has generally taken the form of mean value based methods. This research analyzes...

  11. 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)

    2010-08-17

    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.

  12. Optical temperature sensor using thermochromic semiconductors

    DOE Patents [OSTI]

    Kronberg, J.W.

    1998-06-30

    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.

  13. Optical devices featuring nonpolar textured semiconductor layers

    DOE Patents [OSTI]

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

    2013-11-26

    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, J.W.

    1995-01-01

    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. 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)

    1989-03-28

    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.

  16. Electron gas grid semiconductor radiation detectors

    DOE Patents [OSTI]

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

    2002-01-01

    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.

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

    E-Print Network [OSTI]

    Young, R. Michael

    of technologies dealing with the safe production and use of energy for decades. As early as 1953, NC State's College of Engineering was at the forefront of research with nuclear energy when it began operating, the Atomic Energy Commission authorized the R-1 Reactor at NC State--the first nuclear reactor to be built

  18. Widely tunable frequency conversion in monolithic semiconductor waveguides at 2.4 m

    E-Print Network [OSTI]

    . Department of Electrical and Computer Engineering and the Institute for Optical Sciences, University of Toronto, Toronto, Ontario M5S 3G4, Canada *Corresponding author: a.helmy@utoronto.ca Received March 21 monitoring applications, where a tunable source of coherent radiation tuned between 2 and 3 m wavelength

  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 Data Center Home Page on Delicious RankADVANCED MANUFACTURINGEnergy Bills and ReduceNovemberDOE'sManagementOpenEI

  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

    2014-08-26

    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 Transport in Semiconductor heterostructures

    SciTech Connect (OSTI)

    Domnita Catalina Marinescu

    2011-02-22

    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.

  2. Photoelectrochemistry of Semiconductor Nanowire Arrays

    SciTech Connect (OSTI)

    Mallouk, Thomas E; Redwing, Joan M

    2009-11-10

    This project supported research on the growth and photoelectrochemical characterization of semiconductor nanowire arrays, and on the development of catalytic materials for visible light water splitting to produce hydrogen and oxygen. Silicon nanowires were grown in the pores of anodic aluminum oxide films by the vapor-liquid-solid technique and were characterized electrochemically. Because adventitious doping from the membrane led to high dark currents, silicon nanowire arrays were then grown on silicon substrates. The dependence of the dark current and photovoltage on preparation techniques, wire diameter, and defect density was studied for both p-silicon and p-indium phosphide nanowire arrays. The open circuit photovoltage of liquid junction cells increased with increasing wire diameter, reaching 350 mV for micron-diameter silicon wires. Liquid junction and radial p-n junction solar cells were fabricated from silicon nano- and microwire arrays and tested. Iridium oxide cluster catalysts stabilized by bidentate malonate and succinate ligands were also made and studied for the water oxidation reaction. Highlights of this project included the first papers on silicon and indium phosphide nanowire solar cells, and a new procedure for making ligand-stabilized water oxidation catalysts that can be covalently linked to molecular photosensitizers or electrode surfaces.

  3. SUBMITTED TO THE SPECIAL ISSUE OF IEEE TRANS. ON SEMICONDUCTOR MANUFACTURING 1 Simulation of Semiconductor Manufacturing

    E-Print Network [OSTI]

    SUBMITTED TO THE SPECIAL ISSUE OF IEEE TRANS. ON SEMICONDUCTOR MANUFACTURING 1 Simulation of Semiconductor Manufacturing Supply-Chain Systems with DEVS, MPC, and KIB Dongping Huang, Hessam Sarjoughian1 manufacturing supply-chain systems can be described using a combination of Discrete EVent System Specification

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

    E-Print Network [OSTI]

    Lai, Chun Por

    1988-01-01

    and its associated Fabry-Perot (FP) cavity Semiconductor bandgap diagram Schematic illustration of (a) spontaneous emission and (b) stimulated emission processes Page 10 5. Band diagram of a heterostructure laser diode Light output-current (L... educational goals. vn TABLE OF CONTENTS CHAPTER Page I INTRODUCTION II BASIC OPERATION OF LASER DIODES III ANTIGUIDING INDEX PROFILE 15 A. Analysis B. Design Examples C. Truncated Index Profiles D. Comparsion of Various Wide-Stripe and Array Laser...

  5. Method for removing semiconductor layers from salt substrates

    DOE Patents [OSTI]

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

    1985-08-27

    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.

  6. Conductance matrix of multiterminal semiconductor devices with edge channels

    SciTech Connect (OSTI)

    Danilovskii, E. Yu. Bagraev, N. T.

    2014-12-15

    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.

  7. Semiconductor nanowires for photovoltaic and photoelectrochemical energy conversion

    SciTech Connect (OSTI)

    Dasgupta, Neil; Yang, Peidong

    2013-01-23

    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.

  8. Extracting hot carriers from photoexcited semiconductor nanocrystals

    SciTech Connect (OSTI)

    Zhu, Xiaoyang

    2014-12-10

    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)

    2003-01-01

    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. 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)

    2008-07-29

    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.

  11. Two-Photon Emission from Semiconductors

    E-Print Network [OSTI]

    Alex Hayat; Pavel Ginzburg; Meir Orenstein

    2007-10-25

    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.

  12. 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)

    1989-01-01

    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.

  13. Codoped direct-gap semiconductor scintillators

    DOE Patents [OSTI]

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

    2006-05-23

    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.

  14. Support apparatus for semiconductor wafer processing

    DOE Patents [OSTI]

    Griffiths, Stewart K.; Nilson, Robert H.; Torres, Kenneth J.

    2003-06-10

    A support apparatus for minimizing gravitational stress in semiconductor wafers, and particularly silicon wafers, during thermal processing. The support apparatus comprises two concentric circular support structures disposed on a common support fixture. The two concentric circular support structures, located generally at between 10 and 70% and 70 and 100% and preferably at 35 and 82.3% of the semiconductor wafer radius, can be either solid rings or a plurality of spaced support points spaced apart from each other in a substantially uniform manner. Further, the support structures can have segments removed to facilitate wafer loading and unloading. In order to withstand the elevated temperatures encountered during semiconductor wafer processing, the support apparatus, including the concentric circular support structures and support fixture can be fabricated from refractory materials, such as silicon carbide, quartz and graphite. The claimed wafer support apparatus can be readily adapted for use in either batch or single-wafer processors.

  15. Photonic Band Gaps Based on Tetragonal Lattices of Slanted Pores Ovidiu Toader,1

    E-Print Network [OSTI]

    John, Sajeev

    ) concept [1,2], one of the holy grails of the subject has been the design and synthesis of high quality

  16. Attenuation of optical transmission within the band gap of thin twodimensional macroporous silicon photonic crystals

    E-Print Network [OSTI]

    John, Sajeev

    solution and illuminated from the wafer backside. If applied to a polished silicon wafer, the pore@physics.utoronto.ca b# Present address: Institute for Theory of Condensed Matter, University of Karlsruhe, P.O. Box 6980

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

    SciTech Connect (OSTI)

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

    2012-07-31

    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.

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

    E-Print Network [OSTI]

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

    2006-01-01

    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 ...

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

    E-Print Network [OSTI]

    G. Nimtz; A. A. Stahlhofen

    2008-01-13

    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.

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

    SciTech Connect (OSTI)

    Fan, Yuancheng; Wei, Zeyong; Li, Hongqiang; Chen, Hong; Soukoulis, Costas M

    2013-12-10

    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.

  1. Photonic band gap formation in certain self-organizing systems Kurt Busch and Sajeev John

    E-Print Network [OSTI]

    John, Sajeev

    7 April 1998 We present a detailed study of photonic band structure in certain self frequency are attainable by incom- plete infiltration of an opal with silicon and germanium, respectively are evaluated. We delineate how the PBG is modified by sintering the opal prior to infiltration and by applying

  2. Photonic band gap formation in certain selforganizing systems Kurt Busch and Sajeev John

    E-Print Network [OSTI]

    John, Sajeev

    ~Received 7 April 1998! We present a detailed study of photonic band structure in certain self frequency are attainable by incom­ plete infiltration of an opal with silicon and germanium, respectively are evaluated. We delineate how the PBG is modified by sintering the opal prior to infiltration and by applying

  3. 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 ...

  4. Band gap gratings using quantum well intermixing for quasi-phase-matching

    E-Print Network [OSTI]

    ,b D. C. Hutchings,b J. S. Aitchison, and J. H. Marshc Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario M5S 3G4, Canada, correlated photon pair sources, and cascaded Kerr-like nonlinearities, only to name a few. Particularly

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

    E-Print Network [OSTI]

    Cassett, David Ian, 1971-

    2004-01-01

    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 ...

  6. A study of corporate entrepreneurship in the semiconductor industry

    E-Print Network [OSTI]

    Tallapureddy, Anish R

    2014-01-01

    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 ...

  7. Lattice mismatched compound semiconductors and devices on silicon

    E-Print Network [OSTI]

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

    2011-01-01

    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 ...

  8. Ultrafast optical studies of electronic dynamics in semiconductors

    E-Print Network [OSTI]

    Ruzicka, Brian Andrew

    2012-05-31

    The dynamics of charge carriers in semiconductors are of fundamental importance for semiconductor applications. This includes studies of energy relaxation, carrier recombination, and carrier transport (both diffusive and ballistic). Due...

  9. Electroluminescence in ion gel gated organic polymer semiconductor transistors

    E-Print Network [OSTI]

    Bhat, Shrivalli

    2011-07-12

    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...

  10. 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

  11. Physical properties and analytical models of band-to-band tunneling in low-bandgap semiconductors

    SciTech Connect (OSTI)

    Shih, Chun-Hsing Dang Chien, Nguyen

    2014-01-28

    Low-bandgap semiconductors, such as InAs and InSb, are widely considered to be ideal for use in tunnel field-effect transistors to ensure sufficient on-current boosting at low voltages. This work elucidates the physical and mathematical considerations of applying conventional band-to-band tunneling models in low-bandgap semiconductors, and presents a new analytical alternative for practical use. The high-bandgap tunneling generates most at maximum field region with shortest tunnel path, whereas the low-bandgap generations occur dispersedly because of narrow tunnel barrier. The local electrical field associated with tunneling-electron numbers dominates in low-bandgap materials. This work proposes decoupled electric-field terms in the pre-exponential factor and exponential function of generation-rate expressions. Without fitting, the analytical results and approximated forms exhibit great agreements with the sophisticated forms both in high- and low-bandgap semiconductors. Neither nonlocal nor local field is appropriate to be used in numerical simulations for predicting the tunneling generations in a variety of low- and high-bandgap semiconductors.

  12. Dry etching method for compound semiconductors

    DOE Patents [OSTI]

    Shul, R.J.; Constantine, C.

    1997-04-29

    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.

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

    E-Print Network [OSTI]

    Stone, Peter

    2010-01-01

    5 Ferromagnetic Semiconductors as Spintronicthe previous two examples, spintronic devices aim to exploitdevice [1]. Moreover, spintronic devices are proposed to

  14. Synthesis, Characterization and Applications of InSb Semiconductor Nanowires

    E-Print Network [OSTI]

    Paul, Rajat Kanti

    2011-01-01

    and semiconductor thin films and nanostructures [10, 11]. Recent development of graphene (one atom thick 2D

  15. LINEAR STABILITY OF ELECTRON-FLOW HYDRODYNAMICS IN UNGATED SEMICONDUCTORS

    E-Print Network [OSTI]

    Sen, Mihir

    LINEAR STABILITY OF ELECTRON-FLOW HYDRODYNAMICS IN UNGATED SEMICONDUCTORS A Dissertation Submitted All Rights Reserved #12;LINEAR STABILITY OF ELECTRON-FLOW HYDRODYNAMICS IN UNGATED SEMICONDUCTORS Abstract by Williams R. Calder´on Mu~noz Semiconductors play an important role in modern electronic

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

    DOE Patents [OSTI]

    Norton, David P. (Knoxville, TN)

    2001-01-01

    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.

  17. Semiconductors 80C552/83C552

    E-Print Network [OSTI]

    Berndt, Richard

    Supersedes data of 1998 Jan 06 IC20 Data Handbook 1998 Aug 13 INTEGRATED CIRCUITS #12;Philips SemiconductorsPhilips Semiconductors 80C552/83C552 Single-chip 8-bit microcontroller Product specification VSS VDD AVSS AVDD HIGH ORDER ADDRESS AND DATA BUS #12;Philips Semiconductors Product specification 80C

  18. Amorphous Silicon as Semiconductor Material for High Resolution LAPS

    E-Print Network [OSTI]

    Moritz, Werner

    ) is limited by the properties of the semiconductor material used. We investigated metalAmorphous Silicon as Semiconductor Material for High Resolution LAPS Werner Moritz1 , Tatsuo-insulator- semiconductor (MIS) structures based on amorphous silicon (a-Si) prepared as a thin layer on transparent glass

  19. High-Resolution Three-Dimensional Mapping of Semiconductor Dopant

    E-Print Network [OSTI]

    Dunin-Borkowski, Rafal E.

    ,2 The electrical properties of nanoscale semiconductor structures are strongly dependent on the presence of interfaces and surfaces. Near such features, the electrical properties of the semiconductor may deviate substantially from its bulk properties. Many semiconductor characterization techniques, for example, scanning

  20. 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

  1. Organic conductive films for semiconductor electrodes

    DOE Patents [OSTI]

    Frank, A.J.

    1984-01-01

    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.

  2. Preparation of III-V semiconductor nanocrystals

    DOE Patents [OSTI]

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

    1996-04-09

    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.

  3. Semiconductor laser with multiple lasing wavelengths

    DOE Patents [OSTI]

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

    2003-07-29

    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.

  4. 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

  5. High resolution scintillation detector with semiconductor readout

    DOE Patents [OSTI]

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

    2000-01-01

    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.

  6. Semiconductor detectors with proximity signal readout

    SciTech Connect (OSTI)

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

    2014-01-30

    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.

  7. Optical temperature sensor using thermochromic semiconductors

    DOE Patents [OSTI]

    Kronberg, J.W.

    1994-01-01

    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.

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

    DOE Patents [OSTI]

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

    2013-08-20

    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.

  9. Semiconductor Laser Diode Pumps for Inertial Fusion Energy Lasers

    SciTech Connect (OSTI)

    Deri, R J

    2011-01-03

    Solid-state lasers have been demonstrated as attractive drivers for inertial confinement fusion on the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) and at the Omega Facility at the Laboratory for Laser Energetics (LLE) in Rochester, NY. For power plant applications, these lasers must be pumped by semiconductor diode lasers to achieve the required laser system efficiency, repetition rate, and lifetime. Inertial fusion energy (IFE) power plants will require approximately 40-to-80 GW of peak pump power, and must operate efficiently and with high system availability for decades. These considerations lead to requirements on the efficiency, price, and production capacity of the semiconductor pump sources. This document provides a brief summary of these requirements, and how they can be met by a natural evolution of the current semiconductor laser industry. The detailed technical requirements described in this document flow down from a laser ampl9ifier design described elsewhere. In brief, laser amplifiers comprising multiple Nd:glass gain slabs are face-pumped by two planar diode arrays, each delivering 30 to 40 MW of peak power at 872 nm during a {approx} 200 {micro}s quasi-CW (QCW) pulse with a repetition rate in the range of 10 to 20 Hz. The baseline design of the diode array employs a 2D mosaic of submodules to facilitate manufacturing. As a baseline, they envision that each submodule is an array of vertically stacked, 1 cm wide, edge-emitting diode bars, an industry standard form factor. These stacks are mounted on a common backplane providing cooling and current drive. Stacks are conductively cooled to the backplane, to minimize both diode package cost and the number of fluid interconnects for improved reliability. While the baseline assessment in this document is based on edge-emitting devices, the amplifier design does not preclude future use of surface emitting diodes, which may offer appreciable future cost reductions and increased reliability. The high-level requirements on the semiconductor lasers involve reliability, price points on a price-per-Watt basis, and a set of technical requirements. The technical requirements for the amplifier design in reference 1 are discussed in detail and are summarized in Table 1. These values are still subject to changes as the overall laser system continues to be optimized. Since pump costs can be a significant fraction of the overall laser system cost, it is important to achieve sufficiently low price points for these components. At this time, the price target for tenth-of-akind IFE plant is $0.007/Watt for packaged devices. At this target level, the pumps account for approximately one third of the laser cost. The pump lasers should last for the life of the power plant, leading to a target component lifetime requirement of roughly 14 Ghosts, corresponding to a 30 year plant life and 15 Hz repetition rate. An attractive path forward involes pump operation at high output power levels, on a Watts-per-bar (Watts/chip) basis. This reduces the cost of pump power (price-per-Watt), since to first order the unit price does not increase with power/bar. The industry has seen a continual improvement in power output, with current 1 cm-wide bars emitting up to 500 W QCW (quasi-continuous wave). Increased power/bar also facilitates achieving high irradiance in the array plane. On the other hand, increased power implies greater heat loads and (possibly) higher current drive, which will require increased attention to thermal management and parasitic series resistance. Diode chips containing multiple p-n junctions and quantum wells (also called nanostack structures) may provide an additional approach to reduce the peak current.

  10. Optical cavity furnace for semiconductor wafer processing

    DOE Patents [OSTI]

    Sopori, Bhushan L.

    2014-08-05

    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.

  11. Proximity charge sensing for semiconductor detectors

    DOE Patents [OSTI]

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

    2013-10-08

    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. Method of transferring strained semiconductor structure

    DOE Patents [OSTI]

    Nastasi, Michael A. (Santa Fe, NM); Shao, Lin (College Station, TX)

    2009-12-29

    The transfer of strained semiconductor layers from one substrate to another substrate involves depositing a multilayer structure on a substrate having surface contaminants. An interface that includes the contaminants is formed in between the deposited layer and the substrate. Hydrogen atoms are introduced into the structure and allowed to diffuse to the interface. Afterward, the deposited multilayer structure is bonded to a second substrate and is separated away at the interface, which results in transferring a multilayer structure from one substrate to the other substrate. The multilayer structure includes at least one strained semiconductor layer and at least one strain-induced seed layer. The strain-induced seed layer can be optionally etched away after the layer transfer.

  13. Interconnection-Wide Transmission Planning Initiative - Meeting...

    Energy Savers [EERE]

    Recovery Act Interconnection Transmission Planning Interconnection-Wide Transmission Planning Initiative - Meeting Calendars Interconnection-Wide Transmission Planning...

  14. Semiconductor junction formation by directed heat

    DOE Patents [OSTI]

    Campbell, Robert B. (Pittsburgh, PA)

    1988-03-24

    The process of the invention includes applying precursors 6 with N- and P-type dopants therein to a silicon web 2, with the web 2 then being baked in an oven 10 to drive off excessive solvents, and the web 2 is then heated using a pulsed high intensity light in a mechanism 12 at 1100.degree.-1150.degree. C. for about 10 seconds to simultaneously form semiconductor junctions in both faces of the web.

  15. GaTe semiconductor for radiation detection

    DOE Patents [OSTI]

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

    2009-06-23

    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.

  16. Wide field of view telescope

    DOE Patents [OSTI]

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

    2008-01-15

    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.

  17. Visible-wavelength semiconductor lasers and arrays

    DOE Patents [OSTI]

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

    1996-01-01

    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%.

  18. Environmental Stewardship: How Semiconductor Suppliers Help to Meet Energy-Efficiency Regulations and Voluntary Specifications in China

    E-Print Network [OSTI]

    Aizhen, Li; Fanara, Andrew; Fridley, David; Merriman, Louise; Ju, Jeff

    2008-01-01

    partners, semiconductor suppliers, and other stakeholdersHow Semiconductor Suppliers Help to Meet Energy-Efficiencythe role that semiconductor suppliers can play in meeting

  19. 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.

  20. 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

  1. ENG EC574 Physics and Semiconductor Materials 2007-2008 Catalog Data

    E-Print Network [OSTI]

    of the fundamentals of quantum mechanics necessary to understand the properties of semiconductor materials. Study the basic electrical and optical properties of semiconductor material that are important for semiconductor of the semiconductor material properties. 6. Gain insight on the potential impact of the semiconductor material

  2. 1326 J. Opt. Soc. Am. B/Vol. 10,No. 8/August 1993 Semiconductor laser excitation of Ramsey fringes by using

    E-Print Network [OSTI]

    Shahriar, Selim

    1326 J. Opt. Soc. Am. B/Vol. 10,No. 8/August 1993 Semiconductor laser excitation of Ramsey fringes.2-GHzRaman transition in a cesium atomic beam. Separated-field Ramsey fringes as narrow as 1 kHz wide in the Ramsey dark zone interact with stray fluorescent light.8 Such dark zone interactions are likely

  3. Photovoltaic healing of non-uniformities in semiconductor devices

    DOE Patents [OSTI]

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

    2006-08-29

    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.

  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)

    1987-01-01

    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. Method and system for powering and cooling semiconductor lasers

    DOE Patents [OSTI]

    Telford, Steven J; Ladran, Anthony S

    2014-02-25

    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.

  6. Controlled Chemical Doping of Semiconductor Nanocrystals Using Redox Buffers

    E-Print Network [OSTI]

    Engel, Jesse H.

    2014-01-01

    Controlled Chemical Doping of Semiconductor Nanocrys- talsHerein, we demonstrate a chemical strategy for the con-dope the nanocrystal solid. Chemical doping methods reported

  7. Spin injection and transport in semiconductor and metal nanostructures

    E-Print Network [OSTI]

    Zhu, Lei

    2009-01-01

    1 1.1 Introduction to spintronics: fundamentals andCahay, Introduction to spintronics (CRC Press, Boca Raton,in Semiconductor Spintronics and Quantum Computation, edited

  8. Semiconductor nanowires: from LEDs to Solar Cells | MIT-Harvard...

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

    Semiconductor nanowires: from LEDs to Solar Cells May 4, 2010 at 3pm36-428 Silvija Gradeak Laboratory for Nanophotonics and Electronics, Massachusetts Institute of Technology...

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

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

    suite of breakthrough diamond-based semiconductor inventions developed by nanoscientist Ani Sumant of Argonne's Center for Nanoscale Materials, a DOE Office of Science User...

  10. Semiconductor nanowires for photovoltaic and photoelectrochemical energy conversion

    E-Print Network [OSTI]

    Dasgupta, Neil

    2014-01-01

    low-cost, high efficiency solar energy conversion devices.Awards under the SunShot Solar Energy Technologies Program.Photoelectrochemistry, Solar Energy Abstract Semiconductor

  11. Organic Semiconductor Chemistry | MIT-Harvard Center for Excitonics

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

    Marder Department of ChemistryBiochemistry, Director, Center for Organic Photonics and Electronics, Georgia Tech marder000 Abstract: Organic semiconductors have attracted...

  12. 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)

    1989-10-10

    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.

  13. Interface design principles for high-performance organic semiconductor...

    Office of Scientific and Technical Information (OSTI)

    Interface design principles for high-performance organic semiconductor devices Organic solar cells (OSCs) are a promising cost-effective candidate in next generation photovoltaic...

  14. Hydrogen Evolution at Si-based Metal-Insulator-Semiconductor...

    Office of Scientific and Technical Information (OSTI)

    Hydrogen Evolution at Si-based Metal-Insulator-Semiconductor Photoelectrodes Enhanced by Inversion Channel Charge Collection and Hydrogen Spillover Citation Details In-Document...

  15. 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)

    2011-03-08

    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.

  16. Inorganic semiconductor nanomaterials for flexible and stretchable bio-integrated electronics

    E-Print Network [OSTI]

    Rogers, John A.

    -integrated electronics; flexible electronics; semiconductor nanomaterials; stretchable electronics; transfer printing flexible/stretchable electronics, in which semiconductor nanomaterials serve as the active componentsREVIEW Inorganic semiconductor nanomaterials for flexible and stretchable bio

  17. Chem. Rev. 1995, 95, 69-96 69 Environmental Applications of Semiconductor Photocatalysis

    E-Print Network [OSTI]

    Chem. Rev. 1995, 95, 69-96 69 Environmental Applications of Semiconductor Photocatalysis Michael R November 30, 1994) Contents I. Introduction A. General Background B. Semiconductor Photocatalysis II. Mechanisms of Semiconductor Photocatalysis A. Basic Features and Characteristic Times B. Formation

  18. Transient Rayleigh scattering from single semiconductor nanowires

    SciTech Connect (OSTI)

    Montazeri, Mohammad; Jackson, Howard E.; Smith, Leigh M.; Yarrison-Rice, Jan M.; Kang, Jung-Hyun; Gao, Qiang; Tan, Hark Hoe; Jagadish, Chennupati

    2013-12-04

    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.

  19. Fabrication of Semiconductors by Wet Chemical Etch

    E-Print Network [OSTI]

    Francoviglia, Laura

    2008-07-01

    AlGaAs not intentionally doped (i) 130 Å InGaAs not intentionally doped (i) 30 Å AlGaAs not intentionally doped (i) Delta Si Doping 1.1E12/cm2 Superlattice Buffer GaAs Buffer S.I. GaAs Substrate Epi Layer Structures of V3339 350 Å GaAs 5E18 Si Doping... 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 the computing and electronics...

  20. Hemlock Semiconductor Corp HSC | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIX E LIST OFAMERICA'SHeavy ElectricalsFTLTechnology Srl JumpSubObjectsHemlock Semiconductor

  1. A Hybrid Life Cycle Inventory of Nano-Scale Semiconductor Manufacturing

    E-Print Network [OSTI]

    Krishnan, Nikhil; Boyd, Sarah; Somani, Ajay; Dornfeld, David

    2008-01-01

    Aspects in Semiconductor Manufacturing. Proceed- ings of thefrom semiconductor manufacturing processes. EHS AssessmentM. Energy in chemical manufacturing processes: Gate-to-gate

  2. Semiconductors 4-bit I2C LED dimmer

    E-Print Network [OSTI]

    Berns, Hans-Gerd

    LEDs to 25 mA · Edge rate control on outputs · No glitch on power-up · Supports hot insertion · LowPhilips Semiconductors PCA9533 4-bit I2C LED dimmer Product data sheet Supersedes data of 2003 Sep 19 2004 Oct 01 INTEGRATED CIRCUITS #12;Philips Semiconductors Product data sheet PCA95334-bit I2C LED

  3. Semiconductor Few-Electron Quantum Dots as Spin Qubits

    E-Print Network [OSTI]

    the experimental steps we have taken towards using a single electron spin, trapped in a semiconductor quantum dot detector is pushed to a faster regime (100 kHz), to detect single electron tunnel events in real time. WeSemiconductor Few-Electron Quantum Dots as Spin Qubits J.M. Elzerman1,2 , R. Hanson1 , L.H.W. van

  4. Semiconductors 8-bit multiplying D/A converter

    E-Print Network [OSTI]

    Gustafsson, Torgny

    Philips Semiconductors MC1408-8 8-bit multiplying D/A converter Product data Supersedes data of 1994 Aug 31 File under Integrated Circuits, IC11 Handbook 2001 Aug 03 INTEGRATED CIRCUITS #12;Philips Semiconductors Product data MC1408-88-bit multiplying D/A converter 22001 Aug 03 853-0935 26835 DESCRIPTION

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

    E-Print Network [OSTI]

    Wu, Junqiao

    . The magnitude of this effect in a given material is found to be determined by two material properties of semiconductor nanostructures in terms of their fundamental material parameters. Doping limits in various bulk are generated in semiconductor materials in response to extrinsic doping so as to pull EF back toward EFS

  6. Semiconductor Fundamentals tlu@math.pku.edu.cn

    E-Print Network [OSTI]

    Lu, Tiao

    physics to solid materials. More specifically, we are interested in semiconductor crystals. Crystals. Such a structure yields a periodic potential throughout the material. #12;Introduction Two properties of crystalsSemiconductor Fundamentals tlu@math.pku.edu.cn :http://dsec.pku.edu.cn/~tlu :http

  7. Spherical deformation of compliant substrates with semiconductor device islands

    E-Print Network [OSTI]

    Suo, Zhigang

    is a function of the island structure, size, and substrate material properties. Although the substrate semiconductor device materials, such as amor- phous silicon and silicon nitride, are brittle and crack easily and thinning the substrate cannot be used to reduce the strain. Because inorganic semiconductor materials

  8. NewsTrack -Science New semiconductor technology created

    E-Print Network [OSTI]

    Rogers, John A.

    NewsTrack - Science New semiconductor technology created CHAMPAIGN, Ill., Dec. 14 (UPI) -- U of Illinois-Champaign say the new technology permits either a one- or three-dimensional layout. The approach Rogers Page 1 of 1United Press International - NewsTrack - New semiconductor technology created 12

  9. NICE3 SO3 Cleaning Process in Semiconductor Manufacturing

    SciTech Connect (OSTI)

    Blazek, S.

    1999-01-29

    This fact sheet explains how Anon, Inc., has developed a novel method of removing photoresist--a light-sensitive material used to produce semiconductor wafers for computers--from the computer manufacturing process at reduced cost and greater efficiency. The new technology is technically superior to existing semiconductor cleaning methods and results in reduced use of hazardous chemicals.

  10. Transition metal oxides on organic semiconductors Yongbiao Zhao a

    E-Print Network [OSTI]

    Xiong, Qihua

    inverted organic light-emitting diodes (OLEDs) and inverted organic solar cells (OSCs), which can improve of organic semiconductors (OSs). For example, in organic light-emitting diodes (OLEDs) [7], they are used! Center of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic

  11. Distributed Quantum Computation Architecture Using Semiconductor Nanophotonics

    E-Print Network [OSTI]

    Rodney Van Meter; Thaddeus D. Ladd; Austin G. Fowler; Yoshihisa Yamamoto

    2009-09-17

    In a large-scale quantum computer, the cost of communications will dominate the performance and resource requirements, place many severe demands on the technology, and constrain the architecture. Unfortunately, fault-tolerant computers based entirely on photons with probabilistic gates, though equipped with "built-in" communication, have very large resource overheads; likewise, computers with reliable probabilistic gates between photons or quantum memories may lack sufficient communication resources in the presence of realistic optical losses. Here, we consider a compromise architecture, in which semiconductor spin qubits are coupled by bright laser pulses through nanophotonic waveguides and cavities using a combination of frequent probabilistic and sparse determinstic entanglement mechanisms. The large photonic resource requirements incurred by the use of probabilistic gates for quantum communication are mitigated in part by the potential high-speed operation of the semiconductor nanophotonic hardware. The system employs topological cluster-state quantum error correction for achieving fault-tolerance. Our results suggest that such an architecture/technology combination has the potential to scale to a system capable of attacking classically intractable computational problems.

  12. Coated semiconductor devices for neutron detection

    DOE Patents [OSTI]

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

    2002-01-01

    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.

  13. Impact of ultrathin Al2O3 diffusion barriers on defects in high-k LaLuO3 on Si

    E-Print Network [OSTI]

    lutetium oxide LaLuO3 possesses many attractive properties for MOSFETs: wide optical band gap 5.6 eV ,1

  14. Nonclassical Light from Semiconductor Quantum Wells

    E-Print Network [OSTI]

    P. Grünwald; W. Vogel

    2014-05-06

    The fluorescence light from semiconductor quantum wells is analyzed with respect to its quantum optical properties. The light emitted by the excitons is described by bosonic excitations with a Kerr-type nonlinear interaction. To create the excitons, the incoming pump laser light is absorbed and the absorption acts as a spectral filter for the emitted light. The quantum properties of the emitted light are analyzed for the bare excitonic and the quantum-well systems. Squeezing of the quantum-well fluorescence persists for higher pump laser powers than the squeezing of the excitonic fluorescence. For strong pumping, the nonlinearity suppresses the creation of photon pairs and the photon statistics becomes sub-Poisson.

  15. Modeling direct interband tunneling. I. Bulk semiconductors

    SciTech Connect (OSTI)

    Pan, Andrew; Chui, Chi On

    2014-08-07

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

  16. Polymeric semiconductor/graphene hybrid field-effect transistors Jia Huang a,b,

    E-Print Network [OSTI]

    Polymeric semiconductor/graphene hybrid field-effect transistors Jia Huang a,b, , Daniel R. Hines semiconductor Graphene Thin film transistor Hybrid material a b s t r a c t Solution processed organic field semiconductors and graphene. Compared against OFETs with only pure organic semiconductors, our hybrid FETs

  17. ssentially all semiconductor technology is based on electronic devices, such as

    E-Print Network [OSTI]

    Roukes, Michael L.

    , spintronicsmayalsoleadinthenearfutureto the development of semiconductor devices capable of performing high-speed logic and memory

  18. Simulation of neutron radiation damage in silicon semiconductor devices.

    SciTech Connect (OSTI)

    Shadid, John Nicolas; Hoekstra, Robert John; Hennigan, Gary Lee; Castro, Joseph Pete Jr.; Fixel, Deborah A.

    2007-10-01

    A code, Charon, is described which simulates the effects that neutron damage has on silicon semiconductor devices. The code uses a stabilized, finite-element discretization of the semiconductor drift-diffusion equations. The mathematical model used to simulate semiconductor devices in both normal and radiation environments will be described. Modeling of defect complexes is accomplished by adding an additional drift-diffusion equation for each of the defect species. Additionally, details are given describing how Charon can efficiently solve very large problems using modern parallel computers. Comparison between Charon and experiment will be given, as well as comparison with results from commercially-available TCAD codes.

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

    E-Print Network [OSTI]

    Osterloh, Frank

    on the electronic structure of the semiconductor, that is, they are a materials property. They can be calculated. But besides the semiconductor bandgap no other semiconductor properties are considered in the analysis. Here the band gap, no other semiconductor properties are considered in the model. This cannot account

  20. Carbon p electron ferromagnetism in silicon carbide

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

    Wang, Yutian; Liu, Yu; Wang, Gang; Anwand, Wolfgang; Jenkins, Catherine A.; Arenholz, Elke; Munnik, Frans; Gordan, Ovidiu D.; Salvan, Georgeta; Zahn, Dietrich R. T.; et al

    2015-03-11

    Ferromagnetism can occur in wide-band gap semiconductors as well as in carbon-based materials when specific defects are introduced. It is thus desirable to establish a direct relation between the defects and the resulting ferromagnetism. Here, we contribute to revealing the origin of defect-induced ferromagnetism using SiC as a prototypical example. We show that the long-range ferromagnetic coupling can be attributed to the p electrons of the nearest-neighbor carbon atoms around the VSiVC divacancies. Thus, the ferromagnetism is traced down to its microscopic electronic origin.

  1. 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)

    2014-04-24

    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.

  2. Synthesis and Manipulation of Semiconductor Nanocrystals inMicrofluidic Reactors

    SciTech Connect (OSTI)

    Chan, Emory Ming-Yue

    2006-12-19

    Microfluidic reactors are investigated as a mechanism tocontrol the growth of semiconductor nanocrystals and characterize thestructural evolution of colloidal quantum dots. Due to their shortdiffusion lengths, low thermal masses, and predictable fluid dynamics,microfluidic devices can be used to quickly and reproducibly alterreaction conditions such as concentration, temperature, and reactiontime, while allowing for rapid reagent mixing and productcharacterization. These features are particularly useful for colloidalnanocrystal reactions, which scale poorly and are difficult to controland characterize in bulk fluids. To demonstrate the capabilities ofnanoparticle microreactors, a size series of spherical CdSe nanocrystalswas synthesized at high temperature in a continuous-flow, microfabricatedglass reactor. Nanocrystal diameters are reproducibly controlled bysystematically altering reaction parameters such as the temperature,concentration, and reaction time. Microreactors with finer control overtemperature and reagent mixing were designed to synthesize nanoparticlesof different shapes, such as rods, tetrapods, and hollow shells. The twomajor challenges observed with continuous flow reactors are thedeposition of particles on channel walls and the broad distribution ofresidence times that result from laminar flow. To alleviate theseproblems, I designed and fabricated liquid-liquid segmented flowmicroreactors in which the reaction precursors are encapsulated inflowing droplets suspended in an immiscible carrier fluid. The synthesisof CdSe nanocrystals in such microreactors exhibited reduced depositionand residence time distributions while enabling the rapid screening aseries of samples isolated in nL droplets. Microfluidic reactors werealso designed to modify the composition of existing nanocrystals andcharacterize the kinetics of such reactions. The millisecond kinetics ofthe CdSe-to-Ag2Se nanocrystal cation exchange reaction are measured insitu with micro-X-ray Absorption Spectroscopy in silicon microreactorsspecifically designed for rapid mixing and time-resolved X-rayspectroscopy. These results demonstrate that microreactors are valuablefor controlling and characterizing a wide range of reactions in nLvolumes even when nanoscale particles, high temperatures, causticreagents, and rapid time scales are involved. These experiments providethe foundation for future microfluidic investigations into the mechanismsof nanocrystal growth, crystal phase evolution, and heterostructureassembly.

  3. Freescale Semiconductor Successfully Implements an Energy Management...

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

    projects at its Oak Hill Fab plant in Austin, Texas, that reduced annual plant-wide energy consumption by 28 million kilowatt hours (kWh) of electricity and 26,000 million...

  4. Amorphization of elemental and compound semiconductors upon ion implantation

    E-Print Network [OSTI]

    Florida, University of

    application to semiconductor doping.1 "7 Amorphization is known to reduce the random channeling tails of light, knowledge of the threshold dam- age density may also allow us to use the defects associ- ated with the solid

  5. Improving reuse of semiconductor equipment through benchmarking, standardization, and automation

    E-Print Network [OSTI]

    Silber, Jacob B. (Jacob Bradley)

    2006-01-01

    The 6D program at Intel® Corporation was set up to improve operations around capital equipment reuse, primarily in their semiconductor manufacturing facilities. The company was faced with a number of challenges, including ...

  6. Printable semiconductor structures and related methods of making and assembling

    DOE Patents [OSTI]

    Nuzzo, Ralph G.; Rogers, John A.; Menard, Etienne; Lee, Keon Jae; Khang; , Dahl-Young; Sun, Yugang; Meitl, Matthew; Zhu, Zhengtao; Ko, Heung Cho; Mack, Shawn

    2013-03-12

    The present invention provides a high yield pathway for the fabrication, transfer and assembly of high quality printable semiconductor elements having selected physical dimensions, shapes, compositions and spatial orientations. The compositions and methods of the present invention provide high precision registered transfer and integration of arrays of microsized and/or nanosized semiconductor structures onto substrates, including large area substrates and/or flexible substrates. In addition, the present invention provides methods of making printable semiconductor elements from low cost bulk materials, such as bulk silicon wafers, and smart-materials processing strategies that enable a versatile and commercially attractive printing-based fabrication platform for making a broad range of functional semiconductor devices.

  7. Printable semiconductor structures and related methods of making and assembling

    DOE Patents [OSTI]

    Nuzzo, Ralph G. (Champaign, IL); Rogers, John A. (Champaign, IL); Menard, Etienne (Durham, NC); Lee, Keon Jae (Tokyo, JP); Khang, Dahl-Young (Urbana, IL); Sun, Yugang (Westmont, IL); Meitl, Matthew (Raleigh, NC); Zhu, Zhengtao (Rapid City, SD); Ko, Heung Cho (Urbana, IL); Mack, Shawn (Goleta, CA)

    2011-10-18

    The present invention provides a high yield pathway for the fabrication, transfer and assembly of high quality printable semiconductor elements having selected physical dimensions, shapes, compositions and spatial orientations. The compositions and methods of the present invention provide high precision registered transfer and integration of arrays of microsized and/or nanosized semiconductor structures onto substrates, including large area substrates and/or flexible substrates. In addition, the present invention provides methods of making printable semiconductor elements from low cost bulk materials, such as bulk silicon wafers, and smart-materials processing strategies that enable a versatile and commercially attractive printing-based fabrication platform for making a broad range of functional semiconductor devices.

  8. Printable semiconductor structures and related methods of making and assembling

    DOE Patents [OSTI]

    Nuzzo, Ralph G. (Champaign, IL); Rogers, John A. (Champaign, IL); Menard, Etienne (Urbana, IL); Lee, Keon Jae (Tokyo, JP); Khang, Dahl-Young (Urbana, IL); Sun, Yugang (Westmont, IL); Meitl, Matthew (Champaign, IL); Zhu, Zhengtao (Rapid City, SD); Ko, Heung Cho (Urbana, IL); Mack, Shawn (Goleta, CA)

    2010-09-21

    The present invention provides a high yield pathway for the fabrication, transfer and assembly of high quality printable semiconductor elements having selected physical dimensions, shapes, compositions and spatial orientations. The compositions and methods of the present invention provide high precision registered transfer and integration of arrays of microsized and/or nanosized semiconductor structures onto substrates, including large area substrates and/or flexible substrates. In addition, the present invention provides methods of making printable semiconductor elements from low cost bulk materials, such as bulk silicon wafers, and smart-materials processing strategies that enable a versatile and commercially attractive printing-based fabrication platform for making a broad range of functional semiconductor devices.

  9. DECENTRALIZING SEMICONDUCTOR CAPACITY PLANNING VIA INTERNAL MARKET COORDINATION

    E-Print Network [OSTI]

    Wu, David

    and S. DAVID WU Manufacturing Logistics Institute, Department of Industrial and Manufacturing Systems semiconductor manufacturer: marketing managers reserve capacity from manufacturing based on product demands, while attempting to maximize profit; manufacturing managers allocate capacity to competing marketing

  10. Exploring and enhancing conductivity in semiconductor nanoparticle films

    E-Print Network [OSTI]

    Porter, Venda Jane

    2007-01-01

    Semiconductor nanocrystals (NCs) are a promising material for use in opto-electronic devices as their optical properties tune with particle size. NCs formed via colloidal synthesis are suspended in solution by the organic ...

  11. Thermo-electrically pumped semiconductor light emitting diodes

    E-Print Network [OSTI]

    Santhanam, Parthiban

    2014-01-01

    Thermo-electric heat exchange in semiconductor light emitting diodes (LEDs) allows these devices to emit optical power in excess of the electrical power used to drive them, with the remaining power drawn from ambient heat. ...

  12. Composition/bandgap selective dry photochemical etching of semiconductor materials

    DOE Patents [OSTI]

    Ashby, Carol I. H. (Edgewood, NM); Dishman, James L. (Albuquerque, NM)

    1987-01-01

    A method of selectively photochemically dry etching a first semiconductor material of a given composition and direct bandgap Eg.sub.1 in the presence of a second semiconductor material of a different composition and direct bandgap Eg.sub.2, wherein Eg.sub.2 >Eg.sub.1, said second semiconductor material substantially not being etched during said method, comprises subjecting both materials to the same photon flux and to the same gaseous etchant under conditions where said etchant would be ineffective for chemical etching of either material were the photons not present, said photons being of an energy greater than Eg.sub.1 but less than Eg.sub.2, whereby said first semiconductor material is photochemically etched and said second material is substantially not etched.

  13. Translating semiconductor device physics into nanoparticle films for electronic applications

    E-Print Network [OSTI]

    Wanger, Darcy Deborah

    2014-01-01

    This thesis explores and quantifies some of the important device physics, parameters, and mechanisms of semiconductor nanocrystal quantum dot (QD) electronic devices, and photovoltaic devices in particular. This involves ...

  14. OPTICAL PROPERTIES OF DIELECTRIC AND SEMICONDUCTOR I. Chambouleyron

    E-Print Network [OSTI]

    Martínez, José Mario

    Chapter 12 OPTICAL PROPERTIES OF DIELECTRIC AND SEMICONDUCTOR THIN FILMS I. Chambouleyron Instituto, Young sketched the current theory of color vision in terms of three different (pri- Handbook of Thin

  15. Scanning probe characterization of novel semiconductor materials and devices

    E-Print Network [OSTI]

    Zhou, Xiaotian

    2007-01-01

    structure and properties of semiconductor materials andsemiconductor material systems. In the first part of this dissertation, propertiessemiconductor devices shrink in size, it becomes more important to characterize and understand electronic properties of the materials

  16. Conductive layer for biaxially oriented semiconductor film growth

    DOE Patents [OSTI]

    Findikoglu, Alp T. (Los Alamos, NM); Matias, Vladimir (Santa Fe, NM)

    2007-10-30

    A conductive layer for biaxially oriented semiconductor film growth and a thin film semiconductor structure such as, for example, a photodetector, a photovoltaic cell, or a light emitting diode (LED) that includes a crystallographically oriented semiconducting film disposed on the conductive layer. The thin film semiconductor structure includes: a substrate; a first electrode deposited on the substrate; and a semiconducting layer epitaxially deposited on the first electrode. The first electrode includes a template layer deposited on the substrate and a buffer layer epitaxially deposited on the template layer. The template layer includes a first metal nitride that is electrically conductive and has a rock salt crystal structure, and the buffer layer includes a second metal nitride that is electrically conductive. The semiconducting layer is epitaxially deposited on the buffer layer. A method of making such a thin film semiconductor structure is also described.

  17. Semiconductor nanocrystals : synthesis, mechanisms of formation, and applications in biology

    E-Print Network [OSTI]

    Allen, Peter M. (Peter Matthew)

    2010-01-01

    The primary focus of this thesis is the synthesis and applications of semiconductor nanocrystals, or quantum dots (QDs). Novel synthetic routes to ternary 1-III-VI QDs are presented, and we report the first highly luminescent ...

  18. Three-terminal semiconductor laser for wave mixing 

    E-Print Network [OSTI]

    Belyanin, Alexey; Kocharovsky, V.; Kocharovsky, V.; Scully, Marlan O.

    2002-01-01

    We suggest and analyze the concept of a semiconductor laser device that incorporates two basic ideas: (i) dual-wavelength generation of two optical fields on the interband transitions with independent control of each field in a three...

  19. AlGaN/GaN-based power semiconductor switches

    E-Print Network [OSTI]

    Lu, Bin, Ph. D. Massachusetts Institute of Technology

    2013-01-01

    AlGaN/GaN-based high-electron-mobility transistors (HEMTs) have great potential for their use as high efficiency and high speed power semiconductor switches, thanks to their high breakdown electric field, mobility and ...

  20. Spectral properties of semiconductor nanocrystals and their applications

    E-Print Network [OSTI]

    Liptay, Thomas J. (Thomas John)

    2007-01-01

    The ability to engineer the optical properties of the semiconductor nanocrystals by controlling their growth - size, shape, materials, coatings, etc - makes them appealing for many optical applications. Despite the impressive ...

  1. Brittle and ductile fracture of semiconductor nanowires --molecular dynamics simulations

    E-Print Network [OSTI]

    Cai, Wei

    Brittle and ductile fracture of semiconductor nanowires -- molecular dynamics simulations Keonwook November 9, 2006 Abstract Fracture of silicon and germanium nanowires in tension at room temperature potentials predict brittle fracture initiated by crack nucleation from the surface, most potentials predict

  2. Ultra wide-bandwidth micro energy harvester

    E-Print Network [OSTI]

    Hajati, Arman

    2011-01-01

    An ultra wide-bandwidth resonating thin film PZT MEMS energy harvester has been designed, modeled, fabricated and tested. It harvests energy from parasitic ambient vibration at a wide range of amplitude and frequency via ...

  3. Africa-wide Great Ape Population Surveillance

    E-Print Network [OSTI]

    Schematic illustration of the data collection protocol for our nation-wide survey in Liberia © by Martha

  4. Radioactive Waste Management Complex Wide Review

    Office of Environmental Management (EM)

    This page intentionally blank i Complex-Wide Review of DOE's Radioactive Waste Management Summary Report TABLE OF CONTENTS Acronyms ......

  5. Descreening of field effect in electrically gated nanopores Yang Liu,1,a

    E-Print Network [OSTI]

    Liu, Yang

    , e.g., biosensing under physiological condi- tions 150 mM or desalination of seawater 500 m and desalination.14 In contrast to semiconductors, ionic solutions are essentially zero-band gap conductors

  6. Thermally robust semiconductor optical amplifiers and laser diodes

    DOE Patents [OSTI]

    Dijaili, Sol P. (Moraga, CA); Patterson, Frank G. (Danville, CA); Walker, Jeffrey D. (El Cerrito, CA); Deri, Robert J. (Pleasanton, CA); Petersen, Holly (Manteca, CA); Goward, William (Antioch, CA)

    2002-01-01

    A highly heat conductive layer is combined with or placed in the vicinity of the optical waveguide region of active semiconductor components. The thermally conductive layer enhances the conduction of heat away from the active region, which is where the heat is generated in active semiconductor components. This layer is placed so close to the optical region that it must also function as a waveguide and causes the active region to be nearly the same temperature as the ambient or heat sink. However, the semiconductor material itself should be as temperature insensitive as possible and therefore the invention combines a highly thermally conductive dielectric layer with improved semiconductor materials to achieve an overall package that offers improved thermal performance. The highly thermally conductive layer serves two basic functions. First, it provides a lower index material than the semiconductor device so that certain kinds of optical waveguides may be formed, e.g., a ridge waveguide. The second and most important function, as it relates to this invention, is that it provides a significantly higher thermal conductivity than the semiconductor material, which is the principal material in the fabrication of various optoelectronic devices.

  7. Reconditioning of semiconductor substrates to remove photoresist during semiconductor device fabrication

    DOE Patents [OSTI]

    Farino, Anthony J.

    2004-01-27

    A method for reconditioning the surface of a semiconductor substrate to remove an unwanted (i.e. defective) layer of photoresist is disclosed. The method adapts a conventional automated spinner which is used to rotate the substrate at high speed while a stream of a first solvent (e.g. acetone) is used to dissolve the photoresist. A stream of a second solvent (e.g. methanol) is then used to clean the substrate at a lower speed, with the substrate being allowed to dry with continued rotation. The method of the present invention can be used within a photolithography track so that the substrates need never leave the track for reconditioning.

  8. Competing interactions in semiconductor quantum dots

    SciTech Connect (OSTI)

    van den Berg, R.; Brandino, G. P.; El Araby, O.; Konik, R. M.; Gritsev, V.; Caux, J. -S.

    2014-10-01

    We introduce an integrability-based method enabling the study of semiconductor quantum dot models incorporating both the full hyperfine interaction as well as a mean-field treatment of dipole-dipole interactions in the nuclear spin bath. By performing free induction decay and spin echo simulations we characterize the combined effect of both types of interactions on the decoherence of the electron spin, for external fields ranging from low to high values. We show that for spin echo simulations the hyperfine interaction is the dominant source of decoherence at short times for low fields, and competes with the dipole-dipole interactions at longer times. On the contrary, at high fields the main source of decay is due to the dipole-dipole interactions. In the latter regime an asymmetry in the echo is observed. Furthermore, the non-decaying fraction previously observed for zero field free induction decay simulations in quantum dots with only hyperfine interactions, is destroyed for longer times by the mean-field treatment of the dipolar interactions.

  9. Excitonic exchange splitting in bulk semiconductors

    SciTech Connect (OSTI)

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

    1999-02-01

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

  10. Characterization and electrical modeling of semiconductors bridges

    SciTech Connect (OSTI)

    Marx, K.D.; Bickes, R.W. Jr.; Wackerbarth, D.E.

    1997-03-01

    Semiconductor bridges (SCBs) are finding increased use as initiators for explosive and pyrotechnic devices. They offer advantages in reduced voltage and energy requirements, coupled with excellent safety features. The design of explosive systems which implement either SCBs or metal bridgewires can be facilitated through the use of electrical simulation software such as the PSpice{reg_sign} computer code. A key component in the electrical simulation of such systems is an electrical model of the bridge. This report has two objectives: (1) to present and characterize electrical data taken in tests of detonators which employ SCBs with BNCP as the explosive powder; and (2) to derive appropriate electrical models for such detonators. The basis of such models is a description of the resistance as a function of energy deposited in the SCB. However, two important features which must be added to this are (1) the inclusion of energy loss through such mechanisms as ohmic heating of the aluminum lands and heat transfer from the bridge to the surrounding media; and (2) accounting for energy deposited in the SCB through heat transfer to the bridge from the explosive powder after the powder ignites. The modeling procedure is entirely empirical; i.e., models for the SCB resistance and the energy gain and loss have been estimated from experimental data taken over a range of firing conditions. We present results obtained by applying the model to the simulation of SCB operation in representative tests.

  11. Competing interactions in semiconductor quantum dots

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

    van den Berg, R.; Brandino, G. P.; El Araby, O.; Konik, R. M.; Gritsev, V.; Caux, J. -S.

    2014-10-01

    We introduce an integrability-based method enabling the study of semiconductor quantum dot models incorporating both the full hyperfine interaction as well as a mean-field treatment of dipole-dipole interactions in the nuclear spin bath. By performing free induction decay and spin echo simulations we characterize the combined effect of both types of interactions on the decoherence of the electron spin, for external fields ranging from low to high values. We show that for spin echo simulations the hyperfine interaction is the dominant source of decoherence at short times for low fields, and competes with the dipole-dipole interactions at longer times. Onmore »the contrary, at high fields the main source of decay is due to the dipole-dipole interactions. In the latter regime an asymmetry in the echo is observed. Furthermore, the non-decaying fraction previously observed for zero field free induction decay simulations in quantum dots with only hyperfine interactions, is destroyed for longer times by the mean-field treatment of the dipolar interactions.« less

  12. Semiconductor-inspired superconducting quantum computing

    E-Print Network [OSTI]

    Yun-Pil Shim; Charles Tahan

    2015-07-28

    Superconducting circuits offer tremendous design flexibility in the quantum regime culminating most recently in the demonstration of few qubit systems supposedly approaching the threshold for fault-tolerant quantum information processing. Competition in the solid-state comes from semiconductor qubits, where nature has bestowed some almost magical and very useful properties which can be utilized for spin qubit based quantum computing. Here we begin to explore how selective design principles deduced from spin-based systems could be used to advance superconducting qubit science. We take an initial step along this path proposing an encoded qubit approach realizable with state-of-the-art tunable Josephson junction qubits. Our results show that this design philosophy holds promise, enables microwave-free control with minimal overhead (zero overhead in 2-qubit gates), and offers a pathway to future qubit designs with new capabilities such as with higher fidelity or, perhaps, operation at higher temperature. The approach is especially suited to qubits based on variable super-semi junctions.

  13. Development of epitaxial AlxSc1-xN for artificially structured metal/semiconductor superlattice metamaterials

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

    Sands, Timothy D.; Stach, Eric A.; Saha, Bivas; Saber, Sammy; Naik, Gururaj V.; Boltasseva, Alexandra; Kvam, Eric P.

    2015-02-01

    Epitaxial nitride rocksalt metal/semiconductor superlattices are emerging as a novel class of artificially structured materials that have generated significant interest in recent years for their potential application in plasmonic and thermoelectric devices. Though most nitride metals are rocksalt, nitride semiconductors in general have hexagonal crystal structure. We report rocksalt aluminum scandium nitride (Al,Sc)N alloys as the semiconducting component in epitaxial rocksalt metal/semiconductor superlattices. The AlxSc1-xN alloys when deposited directly on MgO substrates are stabilized in a homogeneous rocksalt (single) phase when x more »the rocksalt phase has been extended to x xSc1-xN alloys show moderate direct bandgap bowing with a bowing parameter, B = 1.41 ± 0.19 eV. The direct bandgap of metastable rocksalt AlN is extrapolated to be 4.70 ± 0.20 eV. The tunable lattice parameter, bandgap, dielectric permittivity, and electronic properties of rocksalt AlxSc1-xN alloys enable high quality epitaxial rocksalt metal/AlxSc1-xN superlattices with a wide range of accessible metamaterials properties.« less

  14. Structure-fluctuation-induced abnormal thermoelectric properties in semiconductor copper selenide

    SciTech Connect (OSTI)

    Liu, Huili [Chinese Academy of Sciences; Shi, Xun [Chinese Academy of Sciences; Kirkham, Melanie J [ORNL; Wang, Hsin [ORNL; Li, Qiang [Brookhaven National Laboratory (BNL); Uher, Ctirad [University of Michigan; Zhang, Wenqing [Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS); Chen, Lidong [Chinese Academy of Sciences

    2013-01-01

    Thermoelectric effects and related technologies have attracted a great interest due to the world-wide energy harvesting. Thermoelectricity has usually been considered in the context of stable material phases. Here we report that the fluctuation of structures during the second-order phase transition in Cu2Se semiconductor breaks the conventional trends of thermoelectric transports in normal phases, leading to a critically phase-transition-enhanced thermoelectric figure of merit zT above unity at 400K, a three times larger value than for the normal phases. Dynamic structural transformations introduce intensive fluctuations and extreme complexity, which enhance the carrier entropy and thus the thermopower, and strongly scatter carriers and phonons as well to make their transports behave critically.

  15. Interconnection-Wide Transmission Planning Initiative: Topic...

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

    State Agency Input Regarding Electric Resource and Transmission Planning in the Texas Interconnection Interconnection-Wide Transmission Planning Initiative: Topic B, State Agency...

  16. Interconnection-Wide Transmission Planning Initiative: Topic...

    Office of Environmental Management (EM)

    A, Interconnection-Level Analysis and Planning Interconnection-Wide Transmission Planning Initiative: Topic A, Interconnection-Level Analysis and Planning A description of the...

  17. Interconnection-Wide Transmission Planning Initiative: Topic...

    Office of Environmental Management (EM)

    Interconnection on Electric Resource Planning and Priorities Interconnection-Wide Transmission Planning Initiative: Topic B, Cooperation Among States in the Eastern...

  18. Interconnection-Wide Transmission Planning Initiative: Topic...

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

    Western Interconnection under the Interconnection-Wide Transmission Planning Initiative, part of the American Recovery and Reinvestment Act. The fundamental purpose of the awards...

  19. DFAS Wide-Area Workflow Issues

    Broader source: Energy.gov [DOE]

    Presentation covers the DFAS wide-area workflow issues and is given at the Spring 2011 Federal Utility Partnership Working Group (FUPWG) meeting.

  20. Semiconductor Nanotechnology: Novel Materials and Devices for Electronics, Photonics, and Renewable Energy Applications

    SciTech Connect (OSTI)

    Goodnick, Stephen; Korkin, Anatoli; Krstic, Predrag S; Mascher, Peter; Preston, John; Zaslavsky, Alex

    2010-03-01

    Electronic and photonic information technology and renewable energy alternatives, such as solar energy, fuel cells and batteries, have now reached an advanced stage in their development. Cost-effective improvements to current technological approaches have made great progress, but certain challenges remain. As feature sizes of the latest generations of electronic devices are approaching atomic dimensions, circuit speeds are now being limited by interconnect bottlenecks. This has prompted innovations such as the introduction of new materials into microelectronics manufacturing at an unprecedented rate and alternative technologies to silicon CMOS architectures. Despite the environmental impact of conventional fossil fuel consumption, the low cost of these energy sources has been a long-standing economic barrier to the development of alternative and more efficient renewable energy sources, fuel cells and batteries. In the face of mounting environmental concerns, interest in such alternative energy sources has grown. It is now widely accepted that nanotechnology offers potential solutions for securing future progress in information and energy technologies. The Canadian Semiconductor Technology Conference (CSTC) forum was established 25 years ago in Ottawa as an important symbol of the intrinsic strength of the Canadian semiconductor research and development community, and the Canadian semiconductor industry as a whole. In 2007, the 13th CSTC was held in Montreal, moving for the first time outside the national capital region. The first three meetings in the series of Nano and Giga Challenges in Electronics and Photonics NGCM2002 in Moscow, NGCM2004 in Krakow, and NGC2007 in Phoenix were focused on interdisciplinary research from the fundamentals of materials science to the development of new system architectures. In 2009 NGC2009 and the 14th Canadian Semiconductor Technology Conference (CSTC2009) were held as a joint event, hosted by McMaster University (10 14 August, Hamilton, Ontario, Canada) and the scope was expanded to include renewable energy research and development. This special issue of Nanotechnology is devoted to a better understanding of the function and design of semiconductor devices that are relevant to information technology (both electronics and photonics based) and renewable energy applications. The papers contained in this special issue are selected from the NGC/CSTC2009 symposium. Among them is a report by Ray LaPierre from McMaster University and colleagues at the University of Waterloo in Canada on the ability to manipulate single spins in nanowire quantum bits. The paper also reports the development of a testbed of a few qubits for general quantum information processing tasks [1]. Lower cost and greater energy conversion efficiency compared with thin film devices have led to a high level of activity in nanowire research related to photovoltaic applications. This special issue also contains results from an impedance spectroscopy study of core shell GaAs nanowires to throw light on the transport and recombination mechanisms relevant to solar cell research [2]. Information technology research and renewable energy sources are research areas of enormous public interest. This special issue addresses both theoretical and experimental achievements and provides a stimulating outlook for technological developments in these highly topical fields of research. References [1] Caram J, Sandoval C, Tirado M, Comedi D, Czaban J, Thompson D A and LaPierre R R 2010 Electrical characteristics of core shell p-n GaAs nanowire structures with Te as the n-dopant Nanotechnology 21 134007 [2] Baugh J, Fung J S and LaPierre R R 2010 Building a spin quantum bit register using semiconductor nanowires Nanotechnology 21 134018

  1. Ultrafast all-optical switching of 3D photonic band gap crystals. T.G. Euser,1,*

    E-Print Network [OSTI]

    Vos, Willem L.

    , Minnesota 55455, USA. 4 Optoelectronics Research Centre (ORC), Tampere University of Technology, Tampere

  2. Pulse propagation in a linear and nonlinear diatomic periodic chain: effects of acoustic frequency band-gap

    E-Print Network [OSTI]

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

    2009-01-01

    as it was demonstrated for PTFE and stainless steel basedusing chains composed of PTFE spheres and stainless steela periodic arrangement of PTFE spheres and stainless steel

  3. Pulse propagation in a linear and nonlinear diatomic periodic chain: effects of acoustic frequency band-gap

    E-Print Network [OSTI]

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

    2009-01-01

    of nonlinear compression pulses in granular media. Prikl.Lindenberg, K. : Short-pulse dynamics in strongly nonlinearQ.M. : In?uence of loading pulse duration on dynamic load

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

    E-Print Network [OSTI]

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

    2015-01-01

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

  5. Forbidden Band Gaps in the Spin-Wave Spectrum of a Two-Dimensional Bicomponent Magnonic Crystal

    E-Print Network [OSTI]

    Grundler, Dirk

    del CNR (CNR-IOM), Unita` di Peru ia, c/o Dipartimento di Fisica, Via A. Pascoli, I-06123 Perugia periodically arranged in a dielectric film have been a powerful concept to induce the Bragg reflection of light

  6. Attenuation of optical transmission within the band gap of thin two-dimensional macroporous silicon photonic crystals

    E-Print Network [OSTI]

    Van Driel, Henry M.

    and illuminated from the wafer backside. If applied to a polished silicon wafer, the pore arrangement becomes address: Institute for Theory of Condensed Matter, University of Karlsruhe, P.O. Box 6980, D-76128

  7. Exploring Visible-Light-Responsive Photocatalysts for Water Splitting Based on Novel Band-gap Engineering Strategies

    E-Print Network [OSTI]

    Liu, Jikai

    2013-01-01

    B 4.3 C before and after photocatalysis reaction (top) and BC 2 before and after photocatalysis reaction (bottom). PageB 4.3 C before and after photocatalysis reaction (top) and B

  8. Light Exiting from Real Photonic Band Gap Crystals is Diffuse and Strongly Directional A. Femius Koenderink* and Willem L. Vos

    E-Print Network [OSTI]

    Vos, Willem L.

    , as it is governed by elastic scattering due to weak disorder [13]. In this Letter we report strongly frequency by this disorder in strongly photonic crystals. Peculiar non-Lambertian distributions occur as a function are tainted by unintentional disorder. Two- and three-dimensional photonic crystals alike suffer from

  9. Pulse propagation in a linear and nonlinear diatomic periodic chain: effects of acoustic frequency band-gap

    E-Print Network [OSTI]

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

    2009-01-01

    J. , Seppa, H. : Microelectromechanical delay lines withusing a slow-wave microelectromechanical delay line in a

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

    E-Print Network [OSTI]

    Honsberg, Christiana

    photovoltaic efficiency of 39% at 236 suns is achieved by a triple-junction GaInP- GaInAs-Ge tandem solar cell [1]. While the achievable efficiency of triple-junction tandem solar cells is restricted to about 40% [2], modeling results show that a tandem solar cell of five junctions or greater, or an equivalent

  11. PHYSICAL REVIEW B 84, 245206 (2011) First-principles study of band gap engineering via oxygen vacancy doping

    E-Print Network [OSTI]

    Rappe, Andrew M.

    2011-01-01

    vacancies can play a beneficial role. For example, in solid oxide fuel cells, oxygen vacancies enable for photovoltaic applications.6­8 Despite the technological relevance of oxygen vacancies in ferroelectric solutions are fundamentally interesting and technologically important. However, experimental

  12. Band Gap Energy of Chalcopyrite Thin Film Solar Cell Absorbers Determined by Soft X-Ray Emission and Absorption Spectroscopy

    E-Print Network [OSTI]

    Bar, M.

    2010-01-01

    OF CHALCOPYRITE THIN FILM SOLAR CELL ABSORBERS DETERMINED BYchalcopyrite thin film solar cell absorbers significantlyof chalcopyrite thin film solar cell absorbers. excitation

  13. Anisotropy-based crystalline oxide-on-semiconductor material

    DOE Patents [OSTI]

    McKee, Rodney Allen (Kingston, TN); Walker, Frederick Joseph (Oak Ridge, TN)

    2000-01-01

    A semiconductor structure and device for use in a semiconductor application utilizes a substrate of semiconductor-based material, such as silicon, and a thin film of a crystalline oxide whose unit cells are capable of exhibiting anisotropic behavior overlying the substrate surface. Within the structure, the unit cells of the crystalline oxide are exposed to an in-plane stain which influences the geometric shape of the unit cells and thereby arranges a directional-dependent quality of the unit cells in a predisposed orientation relative to the substrate. This predisposition of the directional-dependent quality of the unit cells enables the device to take beneficial advantage of characteristics of the structure during operation. For example, in the instance in which the crystalline oxide of the structure is a perovskite, a spinel or an oxide of similarly-related cubic structure, the structure can, within an appropriate semiconductor device, exhibit ferroelectric, piezoelectric, pyroelectric, electro-optic, ferromagnetic, antiferromagnetic, magneto-optic or large dielectric properties that synergistically couple to the underlying semiconductor substrate.

  14. Control of the Casimir Force Using Semiconductor Test Bodies

    E-Print Network [OSTI]

    G. L. Klimchitskaya; U. Mohideen; V. M. Mostepanenko

    2011-04-09

    We describe experimental and related theoretical work on the measurement of the Casimir force using semiconductor test bodies. This field of research started in 2005 and several important and interesting results have already been obtained. Specifically, the Casimir force or its gradient were measured in the configuration of an Au-coated sphere and different semiconductor surfaces. It was found that the force magnitude depends significantly on the replacement of the metal with a semiconductor and on the concentration of charge carriers in the semiconductor material. Special attention is paid to the experiment on the optical modulation of the Casimir force. In this experiment the difference Casimir force between an Au-coated sphere and Si plate in the presence and in the absence of laser light was measured. Possible applications of this experiment are discussed, specifically, for the realization of the pulsating Casimir force in three-layer systems. Theoretical problems arising from the comparison of the experimental data for the difference Casimir force with the Lifshitz theory are analyzed. We consider the possibility to control the magnitude of the Casimir force in phase transitions of semiconductor materials. Experiments on measuring the Casimir force gradient between an Au-coated sphere and Si plate covered with rectangular corrugations of different character are also described. Here, we discuss the interplay between the material properties and nontrivial geometry and the applicability of the proximity force approximation. The review contains comparison between different experiments and analysis of their advantages and disadvantages.

  15. Wavelength-resonant surface-emitting semiconductor laser

    DOE Patents [OSTI]

    Brueck, Steven R. J. (Albuquerque, NM); Schaus, Christian F. (Albuquerque, NM); Osinski, Marek A. (Albuquerque, NM); McInerney, John G. (Cedar Crest, NM); Raja, M. Yasin A. (Albuquerque, NM); Brennan, Thomas M. (Albuquerque, NM); Hammons, Burrell E. (Tijeras, NM)

    1989-01-01

    A wavelength resonant semiconductor gain medium is disclosed. The essential feature of this medium is a multiplicity of quantum-well gain regions separated by semiconductor spacer regions of higher bandgap. Each period of this medium consisting of one quantum-well region and the adjacent spacer region is chosen such that the total width is equal to an integral multiple of 1/2 the wavelength in the medium of the radiation with which the medium is interacting. Optical, electron-beam and electrical injection pumping of the medium is disclosed. This medium may be used as a laser medium for single devices or arrays either with or without reflectors, which may be either semiconductor or external.

  16. Reactive codoping of GaAlInP compound semiconductors

    DOE Patents [OSTI]

    Hanna, Mark Cooper (Boulder, CO); Reedy, Robert (Golden, CO)

    2008-02-12

    A GaAlInP compound semiconductor and a method of producing a GaAlInP compound semiconductor are provided. The apparatus and method comprises a GaAs crystal substrate in a metal organic vapor deposition reactor. Al, Ga, In vapors are prepared by thermally decomposing organometallic compounds. P vapors are prepared by thermally decomposing phospine gas, group II vapors are prepared by thermally decomposing an organometallic group IIA or IIB compound. Group VIB vapors are prepared by thermally decomposing a gaseous compound of group VIB. The Al, Ga, In, P, group II, and group VIB vapors grow a GaAlInP crystal doped with group IIA or IIB and group VIB elements on the substrate wherein the group IIA or IIB and a group VIB vapors produced a codoped GaAlInP compound semiconductor with a group IIA or IIB element serving as a p-type dopant having low group II atomic diffusion.

  17. Efficient semiconductor light-emitting device and method

    DOE Patents [OSTI]

    Choquette, K.D.; Lear, K.L.; Schneider, R.P. Jr.

    1996-02-20

    A semiconductor light-emitting device and method are disclosed. The semiconductor light-emitting device is provided with at least one control layer or control region which includes an annular oxidized portion thereof to channel an injection current into the active region, and to provide a lateral refractive index profile for index guiding the light generated within the device. A periodic composition grading of at least one of the mirror stacks in the device provides a reduced operating voltage of the device. The semiconductor light-emitting device has a high efficiency for light generation, and may be formed either as a resonant-cavity light-emitting diode (RCLED) or as a vertical-cavity surface-emitting laser (VCSEL). 12 figs.

  18. Efficient semiconductor light-emitting device and method

    DOE Patents [OSTI]

    Choquette, Kent D. (Albuquerque, NM); Lear, Kevin L. (Albuquerque, NM); Schneider, Jr., Richard P. (Albuquerque, NM)

    1996-01-01

    A semiconductor light-emitting device and method. The semiconductor light-emitting device is provided with at least one control layer or control region which includes an annular oxidized portion thereof to channel an injection current into the active region, and to provide a lateral refractive index profile for index guiding the light generated within the device. A periodic composition grading of at least one of the mirror stacks in the device provides a reduced operating voltage of the device. The semiconductor light-emitting device has a high efficiency for light generation, and may be formed either as a resonant-cavity light-emitting diode (RCLED) or as a vertical-cavity surface-emitting laser (VCSEL).

  19. Size dependence of the Directional Scattering Conditions on Semiconductor Nanoparticles

    E-Print Network [OSTI]

    Garcia-Camara, Braulio; Cuadrado, Alexander; Urruchi, Virginia; Sanchez-Pena, Jose Manuel; Vergaz, Ricardo

    2015-01-01

    The resonant modes observed in semiconductor nanoparticles and the coherence interaction between them, producing directional light scattering, may be very interesting for CMOS integrated all-optical devices. In these systems the control over the light scattering should be crucial, as well as the strength of this control. Fabrication parameters such as the size and shape of the nanoparticles and the optical properties of the environment can strongly affect to the emergence of these phenomena. In this work, we numerically explore the size dependence of the directional scattering conditions of semiconductor nanoparticles. Several semiconductor materials and a large size range have been considered to be a reference for further works. An interesting and unexpected linear behavior has been observed.

  20. Semiconductor wire array structures, and solar cells and photodetectors based on such structures

    DOE Patents [OSTI]

    Kelzenberg, Michael D.; Atwater, Harry A.; Briggs, Ryan M.; Boettcher, Shannon W.; Lewis, Nathan S.; Petykiewicz, Jan A.

    2014-08-19

    A structure comprising an array of semiconductor structures, an infill material between the semiconductor materials, and one or more light-trapping elements is described. Photoconverters and photoelectrochemical devices based on such structure also described.

  1. Quantitative Determination of Nanoscale Electronic Properties of Semiconductor Surfaces by Scanning Tunnelling Spectroscopy

    E-Print Network [OSTI]

    Feenstra, Randall

    Quantitative Determination of Nanoscale Electronic Properties of Semiconductor Surfaces by Scanning semiconductor surfaces permits quantitative evaluation of nanoscale electronic properties of the surface. Band properties associated with particular point defects within the material. An overview of the methods employed

  2. Cascaded third harmonic generation in hybrid graphene-semiconductor waveguides

    E-Print Network [OSTI]

    Smirnova, Daria A

    2015-01-01

    We study cascaded harmonic generation of hybrid surface plasmons in integrated planar waveguides composed of a graphene layer and a doped-semiconductor slab. We derive a comprehensive model of cascaded third harmonic generation through phase-matched nonlinear interaction of fundamental, second harmonic and third harmonic plasmonic modes supported by the structure. We show that hybrid graphene-semiconductor waveguides can simultaneously phase-match these three interacting harmonics, increasing the total third-harmonic output by a factor of 5 compared to the non-cascaded regime.

  3. Low temperature production of large-grain polycrystalline semiconductors

    DOE Patents [OSTI]

    Naseem, Hameed A. (Fayetteville, AR); Albarghouti, Marwan (Loudonville, NY)

    2007-04-10

    An oxide or nitride layer is provided on an amorphous semiconductor layer prior to performing metal-induced crystallization of the semiconductor layer. The oxide or nitride layer facilitates conversion of the amorphous material into large grain polycrystalline material. Hence, a native silicon dioxide layer provided on hydrogenated amorphous silicon (a-Si:H), followed by deposited Al permits induced crystallization at temperatures far below the solid phase crystallization temperature of a-Si. Solar cells and thin film transistors can be prepared using this method.

  4. Method for depositing layers of high quality semiconductor material

    DOE Patents [OSTI]

    Guha, Subhendu (Troy, MI); Yang, Chi C. (Troy, MI)

    2001-08-14

    Plasma deposition of substantially amorphous semiconductor materials is carried out under a set of deposition parameters which are selected so that the process operates near the amorphous/microcrystalline threshold. This threshold varies as a function of the thickness of the depositing semiconductor layer; and, deposition parameters, such as diluent gas concentrations, must be adjusted as a function of layer thickness. Also, this threshold varies as a function of the composition of the depositing layer, and in those instances where the layer composition is profiled throughout its thickness, deposition parameters must be adjusted accordingly so as to maintain the amorphous/microcrystalline threshold.

  5. Semiconductor microlasers with intracavity microfluidics for biomedical applications

    SciTech Connect (OSTI)

    Gourley, P.L.; McDonald, A.E.

    1997-03-01

    Microfabricated electro-optical-mechanical systems are expected to play an important role in future biomedical, biochemical and environmental technologies. Semiconductor photonic materials and devices are attractive components of such systems because of their ability to generate, transmit, modulate, and detect light. In this paper the authors report investigations of light-emitting semiconductor/glass microcavities filled with simple fluids. They examine surface tension for transporting liquids into the intracavity space and study the influence of the liquid on the spectral emission of the microcavity.

  6. Entrainment by Spatiotemporal Chaos in Glow Discharge-Semiconductor Systems

    E-Print Network [OSTI]

    Marat Akhmet; Ismail Rafatov; Mehmet Onur Fen

    2014-06-15

    Entrainment of limit cycles by chaos [1] is discovered numerically through specially designed unidirectional coupling of two glow discharge-semiconductor systems. By utilizing the auxiliary system approach [2], it is verified that the phenomenon is not a chaos synchronization. Simulations demonstrate various aspects of the chaos appearance in both drive and response systems. Chaotic control is through the external circuit equation and governs the electrical potential on the boundary. The expandability of the theory to collectives of glow discharge systems is discussed, and this increases the potential of applications of the results. Moreover, the research completes the previous discussion of the chaos appearance in a glow discharge-semiconductor system [3].

  7. Features of the electric-field distribution in anisotropic semiconductor wafers in a transverse magnetic field

    SciTech Connect (OSTI)

    Filippov, V. V., E-mail: wwfilippow@mail.ru [Lipetsk State Pedagogical University (Russian Federation); Bormontov, E. N. [Voronezh State University (Russian Federation)

    2013-07-15

    A macroscopic model of the Hall effects and magnetoresistance in anisotropic semiconductor wafers is developed. The results obtained by solving the electrodynamic boundary problem allow the potential and eddy currents in anisotropic semiconductors to be calculated at different current-contact locations, depending on the parameters of the sample material's anisotropy. The results of this study are of great practical importance for investigating the physical properties of anisotropic semiconductors and simulating the electron-transport phenomena in devices based on anisotropic semiconductors.

  8. Contact formation and gettering of precipitated impurities by multiple firing during semiconductor device fabrication

    DOE Patents [OSTI]

    Sopori, Bhushan

    2014-05-27

    Methods for contact formation and gettering of precipitated impurities by multiple firing during semiconductor device fabrication are provided. In one embodiment, a method for fabricating an electrical semiconductor device comprises: a first step that includes gettering of impurities from a semiconductor wafer and forming a backsurface field; and a second step that includes forming a front contact for the semiconductor wafer, wherein the second step is performed after completion of the first step.

  9. Elastic stability and electronic structure of pyrite type PtN2: Ahard semiconductor

    SciTech Connect (OSTI)

    Yu, Rong; Zhan, Qian; Zhang, Xiao-Feng

    2006-08-29

    The elastic properties and electronic structure of PtN2 withthe pyrite structure (PtN2(C2)) were studied with first-principlescalculations. The crystal structure is demonstrated to be elasticallystable with a lower energy than the metastable fluorite structureproposed before. The calculated shear modulus of 214 GPa suggests thatPtN2(C2) is harder than some well known hard materials such as TiN andSiC. The high elastic moduli are attributed to a stacking ofcorner-shared PtN6 octahedra bonded by strong N-N covalent bonding. Incontrast to the metallic fluorite-type phase, PtN2(C2) is semiconductingwith an indirect band gap.

  10. Effect of n-p-n heterostructures on interface recombination and semiconductor laser cooling

    E-Print Network [OSTI]

    Sheik-Bahae, Mansoor

    semiconductor heterostructures such as n-p-n junctions are ubiquitous in electronics and are of increasingEffect of n-p-n heterostructures on interface recombination and semiconductor laser cooling G 2010; published online 13 December 2010 The design of doped n-p-n semiconductor heterostructures has

  11. Novel Logic Devices based on 2D Crystal Semiconductors: Opportunities and Challenges

    E-Print Network [OSTI]

    Novel Logic Devices based on 2D Crystal Semiconductors: Opportunities and Challenges (Invited Paper that the advent of 2D crystal semiconductors has caused excitement in the field [2]. These materials can: djena@nd.edu Abstract Two-dimensional crystal semiconductors such as graphene, BN, and the transition

  12. Cross-sectional scanning tunneling microscopy of mixed-anion semiconductor heterostructures

    E-Print Network [OSTI]

    Yu, Edward T.

    a detailed understanding of atomic- to nanometer-scale properties of semiconductor materials and devices of semiconductor materials and devices at the atomic to nanometer scale. Cross-sectional scanning tunneling and electronic properties in semiconductor epitaxial and device structures with spatial resolution at or near

  13. Metrology-Related Costs in the U.S. Semiconductor Industry,

    E-Print Network [OSTI]

    98-4 Planning Report Metrology-Related Costs in the U.S. Semiconductor Industry, 1990, 1996 Administration #12;Metrology-Related Costs in the U.S. Semiconductor Industry, 1990, 1996 and 2001 NIST Contract Acknowledgements 5 II. Defining Metrology-Related Costs in the Semiconductor Industry 6 A. Physical Measurements

  14. Near-Field Imaging of Nonlinear Optical Mixing in Single Zinc Oxide Nanowires

    E-Print Network [OSTI]

    Cohen, Ronald C.

    no previous studies of the nonlinear optical properties of single semiconductor nanowires. A material independent of wavelength below the energy band gap of semiconductor materials, most often including the 1 Manuscript Received January 16, 2002 ABSTRACT The nonlinear optical response of semiconductor nanowires has

  15. West Wide Programmatic Environmental Impact Statement Record...

    Open Energy Info (EERE)

    Reference LibraryAdd to library Legal Document- OtherOther: West Wide Programmatic Environmental Impact Statement Record of Decision (BLM)Legal Published NA Year Signed or Took...

  16. DOE-wide NEPA Contracting Update

    Broader source: Energy.gov [DOE]

    A DOE team is evaluating the offers received in response to a Request for Quotations to provide NEPA support services. The scope of the solicitation is similar to that of the DOE-wide NEPA support...

  17. Ultra-wide bandwidth piezoelectric energy harvesting

    E-Print Network [OSTI]

    Hajati, Arman

    Here, we present an ultra wide-bandwidth energy harvester by exploiting the nonlinear stiffness of a doubly clamped microelectromechanical systems (MEMSs) resonator. The stretching strain in a doubly clamped beam shows a ...

  18. Attributing Mental Properties to Wide Subjects 

    E-Print Network [OSTI]

    Butts, Evan

    2008-12-04

    Rob Wilson (2001) claims that mental properties are not attributable to wide subjects, despite the claims of authors like Clark and Chalmers (1998). I examine Wilson's objection and endeavor to demonstrate that Clark and Chalmers' account does...

  19. Theory of semiconductor magnetic bipolar transistors M. E. Flattea)

    E-Print Network [OSTI]

    Flatte, Michael E.

    - rating both semiconductors and ferromagnets, such as the spin-valve transistor,12 have demonstrated polarized before passing into the collector. The first is a dramatic spin-filtering effect on carriers passing from the emitter to the p base, the second is spin-selective conduction electron spin flipping

  20. Controlled nanoscale doping of semiconductors via molecular monolayers

    E-Print Network [OSTI]

    California at Berkeley, University of

    -limiting and self-assembly processes where surface and chemical phenomena guide the synthesis and fabrication) the formation of self-assembled monolayers of dopant-containing molecules on the surface of crystalline SiARTICLES Controlled nanoscale doping of semiconductors via molecular monolayers JOHNNY C. HO1