Sample records for doping dual-gated bilayer

  1. Phase transitions in Dual-Gated Bilayer Graphene Gregory S. Boebinger, National High Magnetic Field Laboratory

    E-Print Network [OSTI]

    Weston, Ken

    Phase transitions in Dual-Gated Bilayer Graphene Gregory S. Boebinger, National High Magnetic Field Laboratory DMR-Award 0654118 DC Field Facility Bilayer graphene, consisting of two layers of carbon atoms of the degeneracy of the electronic states in the graphene bilayer. Resistivity plotted as a function of the front

  2. IEEE ELECTRON DEVICE LETTERS, VOL. 21, NO. 12, DECEMBER 2000 549 Dual-Gate AlGaN/GaN Modulation-Doped

    E-Print Network [OSTI]

    Rodwell, Mark J. W.

    IEEE ELECTRON DEVICE LETTERS, VOL. 21, NO. 12, DECEMBER 2000 549 Dual-Gate AlGaN/GaN Modulation--We demonstrate dual-gate AlGaN/GaN modula- tion-doped field-effect transistors (MODFETs) with gate-lengths of 0 power amplifiers. Index Terms--AlGaN/GaN, broadband power amplifiers, dual-gate FETs. I. INTRODUCTION

  3. SiO2 Passivation Effects on the Leakage Current in Dual-Gate AlGaN/GaN High Electron Mobility Transistors

    E-Print Network [OSTI]

    Seo, Kwang Seok

    was grown on c-plane sapphire substrate by MOCVD. Undoped 30 nm-thick Al0.26Ga0.74N and Fe-doped 3 m GaN substrate 3 nm undoped GaN 0.26 0.74 Source DrainMain-GateSiO2 2DEG SiO2 SiO2 Additional Gate 5 m3 m3 m 3 mSiO2 Passivation Effects on the Leakage Current in Dual-Gate AlGaN/GaN High Electron Mobility

  4. Optical Determination of Gate--Tunable Bandgap in Bilayer Graphene

    SciTech Connect (OSTI)

    Zhang, Yuanbo; Tang, Tsung-Ta; Girit, Caglar; Hao, Zhao; Martin, Michael C.; Zettl, Alex; Crommie, Michael F.; Shen, Y. Ron; Wang, Feng

    2009-08-11T23:59:59.000Z

    The electronic bandgap is an intrinsic property of semiconductors and insulators that largely determines their transport and optical properties. As such, it has a central role in modern device physics and technology and governs the operation of semiconductor devices such as p-n junctions, transistors, photodiodes and lasers. A tunable bandgap would be highly desirable because it would allow great flexibility in design and optimization of such devices, in particular if it could be tuned by applying a variable external electric field. However, in conventional materials, the bandgap is fixed by their crystalline structure, preventing such bandgap control. Here we demonstrate the realization of a widely tunable electronic bandgap in electrically gated bilayer graphene. Using a dual-gate bilayer graphene field-effect transistor (FET) and infrared microspectroscopy, we demonstrate a gate-controlled, continuously tunable bandgap of up to 250 meV. Our technique avoids uncontrolled chemical doping and provides direct evidence of a widely tunable bandgap -- spanning a spectral range from zero to mid-infrared -- that has eluded previous attempts. Combined with the remarkable electrical transport properties of such systems, this electrostatic bandgap control suggests novel nanoelectronic and nanophotonic device applications based on graphene.

  5. Bilayer Graphene Photon Detector J. Y. Yan, M.-H. Kim, J. A. Elle, A. B. Sushkov, G. S. Jenkins, H. M. Milchberg

    E-Print Network [OSTI]

    Shapiro, Benjamin

    Bilayer Graphene Photon Detector J. Y. Yan, M.-H. Kim, J. A. Elle, A. B. Sushkov, G. S. Jenkins, H in graphene suggests that "hot electrons" created by incident light can provide the basis for a fast graphene in a "dual-gated" structure. This new "bolometer" has ultralow noise, besting existing detectors

  6. Charge noise analysis of metal oxide semiconductor dual-gate Si/SiGe quantum point contacts

    SciTech Connect (OSTI)

    Kamioka, J.; Oda, S. [Quantum Nanoelectronics Research Center, Tokyo Institute of Technology, 2-12-1-S9-11, Ookayama, Meguro-ku, Tokyo, 152-8552 (Japan); Kodera, T., E-mail: kodera.t.ac@m.titech.ac.jp [Quantum Nanoelectronics Research Center, Tokyo Institute of Technology, 2-12-1-S9-11, Ookayama, Meguro-ku, Tokyo, 152-8552 (Japan); Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1-NE-25, Ookayama, Meguro-ku, Tokyo, 152-8552 (Japan); PRESTO, Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Takeda, K.; Obata, T. [Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Tarucha, S. [Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); RIKEN, Center for Emergent Matter Science (CEMS), 2-1, Hirosawa, Wako, Saitama 351-0198 (Japan)

    2014-05-28T23:59:59.000Z

    The frequency dependence of conductance noise through a gate-defined quantum point contact fabricated on a Si/SiGe modulation doped wafer is characterized. The 1/f{sup 2} noise, which is characteristic of random telegraph noise, is reduced by application of a negative bias on the global top gate to reduce the local gate voltage. Direct leakage from the large global gate voltage also causes random telegraph noise, and therefore, there is a suitable point to operate quantum dot measurement.

  7. A strategy to stabilise the local structure of Ti{sup 4+} and Zn{sup 2+} species against aging in TiO{sub 2}/aluminium-doped ZnO bi-layers for applications in hybrid solar cells

    SciTech Connect (OSTI)

    Pellegrino, Giovanna; La Magna, Antonino; Bongiorno, Corrado; Smecca, Emanuele; Alberti, Alessandra, E-mail: alessandra.alberti@imm.cnr.it [CNR-IMM Zona Industriale VIII Strada 5, 95121 Catania (Italy); Condorelli, Guglielmo G. [Università degli studi di Catania and INSTM UdR Catania V.le A. Doria 6, Catania (Italy); Mocuta, Cristian [Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin BP 48, 91192, Gif-sur-Yvette Cedex (France)

    2014-08-07T23:59:59.000Z

    We explore a strategy to counteract aging issues in TiO{sub 2}/aluminium-doped ZnO bi-layers used in hybrid solar cells photo-anodes, mainly related to Zn diffusion in the TiO{sub 2} matrix. Different Ti{sup 4+} and Zn{sup 2+} local structures within the anatase grains and along the film thickness were found as a function of post-deposition annealing treatments in the range between 200?°C and 500?°C by synchrotron radiation extended x-ray absorption fine structure analyses. In particular, in the 500?°C-treated sample, diffusion of zinc species along the TiO{sub 2} grain-boundaries has been observed with aging (3?years). In contrast, a mild thermal budget at 200?°C favours a proper atomic arrangement of the zinc-containing anatase lattice which reduces Zn diffusion, thus guaranteeing a good stability with aging.

  8. Bilayer Graphene Gets a Bandgap

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

    Bilayer Graphene Gets a Bandgap Bilayer Graphene Gets a Bandgap Print Wednesday, 26 August 2009 00:00 Graphene is the two-dimensional crystalline form of carbon whose extraordinary...

  9. Twist Solves Bilayer Graphene Mystery

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

    Twist Solves Bilayer Graphene Mystery Twist Solves Bilayer Graphene Mystery Print Wednesday, 26 March 2014 00:00 Researchers have discovered a unique new twist to the story of...

  10. Immobilized lipid-bilayer materials

    DOE Patents [OSTI]

    Sasaki, Darryl Y. (Albuquerque, NM); Loy, Douglas A. (Albuquerque, NM); Yamanaka, Stacey A. (Dallas, TX)

    2000-01-01T23:59:59.000Z

    A method for preparing encapsulated lipid-bilayer materials in a silica matrix comprising preparing a silica sol, mixing a lipid-bilayer material in the silica sol and allowing the mixture to gel to form the encapsulated lipid-bilayer material. The mild processing conditions allow quantitative entrapment of pre-formed lipid-bilayer materials without modification to the material's spectral characteristics. The method allows for the immobilization of lipid membranes to surfaces. The encapsulated lipid-bilayer materials perform as sensitive optical sensors for the detection of analytes such as heavy metal ions and can be used as drug delivery systems and as separation devices.

  11. Bilayer Graphene Gets a Bandgap

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

    Bilayer Graphene Gets a Bandgap Print Graphene is the two-dimensional crystalline form of carbon whose extraordinary electron mobility and other unique features hold great promise...

  12. Optical Determination of Gate--Tunable Bandgap in Bilayer Graphene

    E-Print Network [OSTI]

    Zhang, Yuanbo

    2010-01-01T23:59:59.000Z

    Tunable Bandgap in Bilayer Graphene Yuanbo Zhang* 1 , Tsung-gate-tunable bandgap in graphene bilayers with magnitude asbands. In two- dimensional graphene bilayers this bandgap

  13. Lipid bilayers on nano-templates

    DOE Patents [OSTI]

    Noy, Aleksandr (Belmont, CA); Artyukhin, Alexander B. (Menlo Park, CA); Bakajin, Olgica (San Leandro, CA); Stoeve, Pieter (Davis, CA)

    2009-08-04T23:59:59.000Z

    A lipid bilayer on a nano-template comprising a nanotube or nanowire and a lipid bilayer around the nanotube or nanowire. One embodiment provides a method of fabricating a lipid bilayer on a nano-template comprising the steps of providing a nanotube or nanowire and forming a lipid bilayer around the polymer cushion. One embodiment provides a protein pore in the lipid bilayer. In one embodiment the protein pore is sensitive to specific agents

  14. Minimal Bending Energies of Bilayer Polyhedra

    E-Print Network [OSTI]

    Christoph A. Haselwandter; Rob Phillips

    2011-06-10T23:59:59.000Z

    Motivated by recent experiments on bilayer polyhedra composed of amphiphilic molecules, we study the elastic bending energies of bilayer vesicles forming polyhedral shapes. Allowing for segregation of excess amphiphiles along the ridges of polyhedra, we find that bilayer polyhedra can indeed have lower bending energies than spherical bilayer vesicles. However, our analysis also implies that, contrary to what has been suggested on the basis of experiments, the snub dodecahedron, rather than the icosahedron, generally represents the energetically favorable shape of bilayer polyhedra.

  15. Twist Solves Bilayer Graphene Mystery

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

    Twist Solves Bilayer Graphene Mystery Print Researchers have discovered a unique new twist to the story of graphene and, in the process, appear to have solved a mystery that has...

  16. Band Structure Asymmetry of Bilayer Graphene Revealed by Infrared Spectroscopy

    SciTech Connect (OSTI)

    Li, Z.Q.; Henriksen, E.A.; Jiang, Z.; Hao, Zhao; Martin, Michael C.; Kim, P.; Stormer, H.L.; Basov, Dimitri N.

    2008-12-10T23:59:59.000Z

    We report on infrared spectroscopy of bilayer graphene integrated in gated structures. We observe a significant asymmetry in the optical conductivity upon electrostatic doping of electrons and holes. We show that this finding arises from a marked asymmetry between the valence and conduction bands, which is mainly due to the inequivalence of the two sublattices within the graphene layer and the next-nearest-neighbor interlayer coupling. From the conductivity data, the energy difference of the two sublattices and the interlayer coupling energy are directly determined.

  17. Transverse electric plasmons in bilayer graphene

    E-Print Network [OSTI]

    Jablan, Marinko

    We predict the existence of transverse electric (TE) plasmons in bilayer graphene. We find that their plasmonic properties are much more pronounced in bilayer than in monolayer graphene, in a sense that they can get more ...

  18. Bilayer Graphene Gets a Bandgap

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041clothAdvanced Materials Advanced Materials Find MoreLawrenceDepartment» BilateralBilayerBilayer

  19. Bilayer Graphene Gets a Bandgap

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

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

    SciTech Connect (OSTI)

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

    2014-02-17T23:59:59.000Z

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

  1. STABLE HIGH CONDUCTIVITY BILAYERED ELECTROLYTES FOR LOW TEMPERATURE SOLID OXIDE FUEL CELLS

    SciTech Connect (OSTI)

    Eric D. Wachsman; Keith L. Duncan

    2002-09-30T23:59:59.000Z

    A bilayer electrolyte consisting of acceptor-doped ceria (on the fuel/reducing side) and cubic-stabilized bismuth oxide (on the oxidizing side) was developed. The bilayer electrolyte that was developed showed significant improvement in open-circuit potential versus a typical ceria based SOFC. Moreover, the OCP of the bilayer cells increased as the thickness of the bismuth oxide layer increased relative to the ceria layer. Thereby, verifying the bilayer concept. Although, because of the absence of a suitable cathode (a problem we are still working assiduously to solve), we were unable to obtain power density curves, our modeling work predicts a reduction in electrolyte area specific resistance of two orders of magnitude over cubic-stabilized zirconia and projects a maximum power density of 9 W/m{sup 2} at 800 C and 0.09 W/m{sup 2} at 500 C. Towards the development of the bilayer electrolyte other significant strides were made. Among these were, first, the development of a, bismuth oxide based, oxide ion conductor with the highest conductivity (0.56 S/cm at 800 C and 0.043 S/cm at 500 C) known to date. Second, a physical model of the defect transport mechanisms and the driving forces for the ordering phenomena in bismuth oxide and other fluorite systems was developed. Third, a model for point defect transport in oxide mixed ionic-electronic conductors was developed, without the typical assumption of a uniform distribution of ions and including the effect of variable loads on the transport properties of an SOFC (with either a single or bilayer electrolyte).

  2. Twist Solves Bilayer Graphene Mystery

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

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

  3. Bilayer Graphene Gets a Bandgap

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  4. Bilayer Graphene Gets a Bandgap

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041clothAdvanced Materials Advanced Materials Find MoreLawrenceDepartment» BilateralBilayer

  5. Bilayer Graphene Gets a Bandgap

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041clothAdvanced Materials Advanced Materials Find MoreLawrenceDepartment»Bilayer Graphene Gets a

  6. Bilayer Graphene Gets a Bandgap

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041clothAdvanced Materials Advanced Materials Find MoreLawrenceDepartment»Bilayer Graphene Gets

  7. "Nanocrystal bilayer for tandem catalysis"

    SciTech Connect (OSTI)

    Yamada, Yusuke; Tsung, Chia Kuang; Huang, Wenyu; Huo, Ziyang; E.Habas, Susan E; Soejima, Tetsuro; Aliaga, Cesar E; Samorjai, Gabor A; Yang, Peidong

    2011-01-24T23:59:59.000Z

    Supported catalysts are widely used in industry and can be optimized by tuning the composition and interface of the metal nanoparticles and oxide supports. Rational design of metal-metal oxide interfaces in nanostructured catalysts is critical to achieve better reaction activities and selectivities. We introduce here a new class of nanocrystal tandem catalysts that have multiple metal-metal oxide interfaces for the catalysis of sequential reactions. We utilized a nanocrystal bilayer structure formed by assembling platinum and cerium oxide nanocube monolayers of less than 10 nm on a silica substrate. The two distinct metal-metal oxide interfaces, CeO2-Pt and Pt-SiO2, can be used to catalyse two distinct sequential reactions. The CeO2-Pt interface catalysed methanol decomposition to produce CO and H2, which were subsequently used for ethylene hydroformylation catalysed by the nearby Pt-SiO2 interface. Consequently, propanal was produced selectively from methanol and ethylene on the nanocrystal bilayer tandem catalyst. This new concept of nanocrystal tandem catalysis represents a powerful approach towards designing high-performance, multifunctional nanostructured catalysts

  8. Surface tension and electroporation of lipid bilayers

    E-Print Network [OSTI]

    Cho, Han-Jae Jeremy

    2011-01-01T23:59:59.000Z

    Electroporation of lipid bilayers is widely used in DNA transfection, gene therapy, and targeted drug delivery and has potential applications in water desalination and filtration. A better, more thorough molecular understanding ...

  9. Possible mechanism of adhesion in a mica supported phospholipid bilayer

    SciTech Connect (OSTI)

    Pertsin, Alexander, E-mail: ig3@ix.urz.uni-heidelberg.de [Angewandte Physikalische Chemie, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg (Germany) [Angewandte Physikalische Chemie, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg (Germany); Institute of Organo-Element Compounds, Russian Academy of Sciences, Vavilov Str. 28, 117991 Moscow (Russian Federation); Grunze, Michael [Angewandte Physikalische Chemie, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg (Germany) [Angewandte Physikalische Chemie, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg (Germany); Institute for Functional Interfaces, Karlsruhe Institute of Technology, Hermann-von- Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2014-05-14T23:59:59.000Z

    Phospholipid bilayers supported on hydrophilic solids like silica and mica play a substantial role in fundamental studies and technological applications of phospholipid membranes. In both cases the molecular mechanism of adhesion between the bilayer and the support is of primary interest. Since the possibilities of experimental methods in this specific area are rather limited, the methods of computer simulation acquire great importance. In this paper we use the grand canonical Monte Carlo technique and an atomistic force field to simulate the behavior of a mica supported phospholipid bilayer in pure water as a function of the distance between the bilayer and the support. The simulation reveals a possible adhesion mechanism, where the adhesion is due to individual lipid molecules that protrude from the bilayer and form widely spaced links with the support. Simultaneously, the bilayer remains separated from the bilayer by a thin water interlayer which maintains the bilayer fluidity.

  10. Lipid bilayer and cytoskeletal interactions in a red blood cell

    E-Print Network [OSTI]

    Peng, Zhangli

    We study the biomechanical interactions between the lipid bilayer and the cytoskeleton in a red blood cell (RBC) by developing a general framework for mesoscopic simulations. We treated the lipid bilayer and the cytoskeleton ...

  11. Adsorption on tunable bilayer graphene: A model approach

    SciTech Connect (OSTI)

    Alisultanov, Z. Z., E-mail: zaur0102@gmail.com [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation)

    2013-07-15T23:59:59.000Z

    The problem of the adsorption of atoms on the surface of tunable bilayer graphene is considered within the context of Anderson's model. Analytical expressions for the densities of states of bilayer graphene and an adatom are derived, and the charge exchange between adatoms and bilayer graphene is studied. The charge of adatoms of some elements is estimated. The change induced in the density of states of tunable bilayer graphene by the adsorption of atoms is explored.

  12. hal00276997, Raman spectra of misoriented bilayer graphene

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    hal­00276997, version 1 ­ 5 May 2008 Raman spectra of misoriented bilayer graphene P. Poncharal 1 spectra from single layer graphene with a bilayer in which the two layers are arbitrarily misoriented to the similarity of the electronic structures of single layer graphene and misoriented bilayer graphene. Another

  13. Bilayer graphene quantum dot defined by topgates

    SciTech Connect (OSTI)

    Müller, André; Kaestner, Bernd; Hohls, Frank; Weimann, Thomas; Pierz, Klaus; Schumacher, Hans W., E-mail: hans.w.schumacher@ptb.de [Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig (Germany)

    2014-06-21T23:59:59.000Z

    We investigate the application of nanoscale topgates on exfoliated bilayer graphene to define quantum dot devices. At temperatures below 500 mK, the conductance underneath the grounded gates is suppressed, which we attribute to nearest neighbour hopping and strain-induced piezoelectric fields. The gate-layout can thus be used to define resistive regions by tuning into the corresponding temperature range. We use this method to define a quantum dot structure in bilayer graphene showing Coulomb blockade oscillations consistent with the gate layout.

  14. Brownian Ratchets: Molecular Separations in Lipid Bilayers

    E-Print Network [OSTI]

    Boxer, Steven G.

    Brownian Ratchets: Molecular Separations in Lipid Bilayers Supported on Patterned Arrays Alexander van Oudenaarden and Steven G. Boxer* Brownian ratchets use a time-varying asymmetric potential that can be applied to separate diffusing particles or molecules. A new type of Brownian ratchet

  15. Budding of domains in mixed bilayer membranes

    E-Print Network [OSTI]

    Jean Wolff; Shigeyuki Komura; David Andelman

    2015-01-10T23:59:59.000Z

    We propose a model that accounts for budding behavior of domains in lipid bilayers, where each of the bilayer leaflets has a coupling between its local curvature and local lipid composition. The compositional asymmetry between the two monolayers leads to an overall spontaneous curvature. The membrane free-energy contains three contributions: bending energy, line tension, and a Landau free-energy for a lateral phase separation. Within a mean-field treatment, we obtain various phase diagrams which contain fully-budded, dimpled and flat states. In particular, for some range of membrane parameters, the phase diagrams exhibit a tricritical behavior as well as three-phase coexistence region. The global phase diagrams can be divided into three types and are analyzed in terms of the curvature-composition coupling parameter and domain size.

  16. Landau problem for bilayer graphene: Exact results

    E-Print Network [OSTI]

    Young-Hwan Hyun; Yoonbai Kim; Corneliu Sochichiu; Min-Young Choi

    2010-08-03T23:59:59.000Z

    We consider graphene bilayer in a constant magnetic field of arbitrary orientation (i.e. tilted with respect to the graphene plane). In the low energy approximation to tight binding model with Peierls substitution, we find the exact spectrum of Landau levels. This spectrum is two-fold degenerate in the limit of large in-plane field, which gives rise to a new SU(2) symmetry in this limit.

  17. How Bilayer Graphene Got a Bandgap

    ScienceCinema (OSTI)

    Feng Wang

    2010-01-08T23:59:59.000Z

    Graphene is the two-dimensional crystalline form of carbon, whose extraordinary electron mobility and other unique features hold great promise for nanoscale electronics and photonics. But theres a catch: graphene has no bandgap. Now Feng Wang and his colleagues at Berkeley Lab and UC Berkeley have engineered a bandgap in bilayer graphene that can be precisely controlled from 0 to 250 milli-electron volts, which is the energy of infrared radiation.

  18. How Bilayer Graphene Got a Bandgap

    ScienceCinema (OSTI)

    Wang, Feng

    2013-05-29T23:59:59.000Z

    Graphene is the two-dimensional crystalline form of carbon, whose extraordinary electron mobility and other unique features hold great promise for nanoscale electronics and photonics. But theres a catch: graphene has no bandgap. Now Feng Wang and his colleagues at Berkeley Lab and UC Berkeley have engineered a bandgap in bilayer graphene that can be precisely controlled from 0 to 250 milli-electron volts, which is the energy of infrared radiation.

  19. Slip corona surrounding bilayer graphene nanopore Yunwei Maob

    E-Print Network [OSTI]

    Chen, Sow-Hsin

    Slip corona surrounding bilayer graphene nanopore Liang Qi,a Yunwei Maob and Ju Li*abc Received 5th of bilayer graphene (BLG) depend on the stacking order between the two layers. We introduce a new conceptual and low interlayer shear resistance between two adjacent layers of graphene. The continuum model also

  20. Hot Carrier-Assisted Intrinsic Photoresponse in Graphene

    E-Print Network [OSTI]

    Gabor, Nathaniel M.

    We report on the intrinsic optoelectronic response of high-quality dual-gated monolayer and bilayer graphene p-n junction devices. Local laser excitation (of wavelength 850 nanometers) at the p-n interface leads to striking ...

  1. Collective Excitations in Electron-Hole Bilayers

    SciTech Connect (OSTI)

    Kalman, G. J. [Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467 (United States); Hartmann, P.; Donko, Z. [Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Golden, K. I. [Department of Mathematics and Statistics and Department of Physics, University of Vermont, Burlington, Vermont 05401 (United States)

    2007-06-08T23:59:59.000Z

    We report a combined analytic and molecular dynamics analysis of the collective mode spectrum of a bipolar (electron-hole) bilayer in the strong coupling classical limit. A robust, isotropic energy gap is identified in the out-of-phase spectra, generated by the combined effect of correlations and of the excitation of the bound dipoles. In the in-phase spectra we identify longitudinal and transverse acoustic modes wholly maintained by correlations. Strong nonlinear generation of higher harmonics of the fundamental dipole oscillation frequency and the transfer of harmonics between different modes is observed.

  2. Self-assembled lipid bilayer materials

    DOE Patents [OSTI]

    Sasaki, Darryl Y.; Waggoner, Tina A.; Last, Julie A.

    2005-11-08T23:59:59.000Z

    The present invention is a self-assembling material comprised of stacks of lipid bilayers formed in a columnar structure, where the assembly process is mediated and regulated by chemical recognition events. The material, through the chemical recognition interactions, has a self-regulating system that corrects the radial size of the assembly creating a uniform diameter throughout most of the structure. The materials form and are stable in aqueous solution. These materials are useful as structural elements for the architecture of materials and components in nanotechnology, efficient light harvesting systems for optical sensing, chemical processing centers, and drug delivery vehicles.

  3. STABLE HIGH CONDUCTIVITY BILAYERED ELECTROLYTES FOR LOW TEMPERATURE SOLID OXIDE FUEL CELLS

    SciTech Connect (OSTI)

    Eric D. Wachsman

    2000-10-01T23:59:59.000Z

    Solid oxide fuel cells (SOFCs) are the future of energy production in America. They offer great promise as a clean and efficient process for directly converting chemical energy to electricity while providing significant environmental benefits (they produce negligible CO, HC, or NOx and, as a result of their high efficiency, produce about one-third less CO{sub 2} per kilowatt hour than internal combustion engines). Unfortunately, the current SOFC technology, based on a stabilized zirconia electrolyte, must operate in the region of 1000 C to avoid unacceptably high ohmic losses. These high temperatures demand (a) specialized (expensive) materials for the fuel cell interconnects and insulation, (b) time to heat up to the operating temperature and (c) energy input to arrive at the operating temperature. Therefore, if fuel cells could be designed to give a reasonable power output at lower temperatures tremendous benefits may be accrued, not the least of which is reduced cost. The problem is, at lower temperatures the conductivity of the conventional stabilized zirconia electrolyte decreases to the point where it cannot supply electrical current efficiently to an external load. The primary objectives of the proposed research is to develop a stable high conductivity (>0.05 S cm{sup -1} at 550 C) electrolyte for lower temperature SOFCs. This objective is specifically directed toward meeting the lowest (and most difficult) temperature criteria for the 21st Century Fuel Cell Program. Meeting this objective provides a potential for future transportation applications of SOFCs, where their ability to directly use hydrocarbon fuels could permit refueling within the existing transportation infrastructure. In order to meet this objective we are developing a functionally gradient bilayer electrolyte comprised of bismuth oxide on the air side and ceria on the fuel side. Bismuth oxide and doped ceria are among the highest ionic conducting electrolytes and in fact bismuth oxide based electrolytes are the only known solid oxide electrolytes to have an ionic conductivity that meets the program conductivity goal. We have previously demonstrated that this concept works, that a bismuth oxide/ceria bilayer electrolyte provides near theoretical open circuit potential (OCP) and is stable for 1400 h of fuel cell operation under both open circuit and maximum power conditions. More recently, we developed a computer model to determine the defect transport in this bilayer and have found that a bilayer comprised primarily of the more conductive component (bismuth oxide) is stable for 500 C operation. In this first year of the project we are obtaining necessary thermochemical data to complete the computer model as well as initial SOFC results based on thick 1-2 mm single and bilayer ceria/bismuth oxide electrolytes. We will use the computer model to obtain the optimum relative layer thickness as a function of temperature and air/fuel conditions. SOFCs will be fabricated with 1-2 mm single and bilayer electrolytes based on the modeling results, tested for OCP, conductivity, and stability and compared against the predictions. The computer modeling is a continuation of previous work under support from GRI and the student was available at the inception of the contract. However, the experimental effort was delayed until the beginning of the Spring Semester because the contract was started in October, 2 months after the start of our Fall Semester, and after all of the graduate students were committed to other projects. The results from both of these efforts are described in the following two sections: (1) Experimental; and (2) Computer Modeling.

  4. Collective Dynamics of Complex Plasma Bilayers

    SciTech Connect (OSTI)

    Hartmann, P.; Donko, Z. [Research Institute for Solid State Physics and Optics of the Hungarian Academy of Sciences, H-1525 Budapest, P.O. Box 49 (Hungary); Department of Physics, Boston College, 140 Commonwealth Avenue, Chestnut Hill, Massachusetts 02467 (United States); Kalman, G. J. [Department of Physics, Boston College, 140 Commonwealth Avenue, Chestnut Hill, Massachusetts 02467 (United States); Kyrkos, S. [Department of Chemistry and Physics, Le Moyne College, 1419 Salt Springs Road, Syracuse, New York 13214 (United States); Golden, K. I. [Department of Mathematics and Statistics, College of Engineering and Mathematical Sciences, University of Vermont, Burlington, Vermont 05401-1455 (United States); Rosenberg, M. [Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, California, 92093 (United States)

    2009-12-11T23:59:59.000Z

    A classical dusty plasma experiment was performed using two different dust grain sizes to form a strongly coupled asymmetric bilayer (two closely spaced interacting monolayers) of two species of charged dust particles. The observation and analysis of the thermally excited particle oscillations revealed the collective mode structure and dispersion (wave propagation) in this system; in particular, the existence of the theoretically predicted k=0 energy (frequency) gap was verified. Equilibrium molecular-dynamics simulations were performed to emulate the experiment, assuming Yukawa-type interparticle interaction. The simulations and analytic calculations based both on lattice summation and on the quasilocalized charge approximation approach are in good agreement with the experimental findings and help in identifying and characterizing the observed phenomena.

  5. Electrostatic and Magnetic Fields in Bilayer Graphene

    E-Print Network [OSTI]

    Ahmed Jellal; Ilham Redouani; Hocine Bahlouli

    2014-11-14T23:59:59.000Z

    We compute the transmission probability through rectangular potential barriers and p-n junctions in the presence of a magnetic and electric fields in bilayer graphene taking into account the full four bands of the energy spectrum. For energy E higher than the interlayer coupling $\\gamma_1 (E>\\gamma_1)$ two propagation modes are available for transport giving rise to four possible ways for transmission and reflection probabilities. However, when the energy is less then the height of the barrier the Dirac fermions exhibits transmission resonances and only one mode of propagation is available. We study the effect of the interlayer electrostatic potential $\\delta$ and the different geometry parameters of the barrier on the transmission probability.

  6. Chiral tunneling in single and bilayer graphene

    E-Print Network [OSTI]

    T. Tudorovskiy; K. J. A. Reijnders; M. I. Katsnelson

    2011-06-15T23:59:59.000Z

    We review chiral (Klein) tunneling in single-layer and bilayer graphene and present its semiclassical theory, including the Berry phase and the Maslov index. Peculiarities of the chiral tunneling are naturally explained in terms of classical phase space. In a one-dimensional geometry we reduced the original Dirac equation, describing the dynamics of charge carriers in the single layer graphene, to an effective Schr\\"odinger equation with a complex potential. This allowed us to study tunneling in details and obtain analytic formulas. Our predictions are compared with numerical results. We have also demonstrated that, for the case of asymmetric n-p-n junction in single layer graphene, there is total transmission for normal incidence only, side resonances are suppressed.

  7. Anisotropic transport properties of ferromagnetic-superconducting bilayers

    E-Print Network [OSTI]

    Kayali, MA; Pokrovsky, Valery L.

    2004-01-01T23:59:59.000Z

    . Erdin [Phys. Rev. Lett. 88, 017001 (2002)]. We calculate the periodic pinning force in the stripe structure resulting from a highly inhomogeneous distribution of the vortices and antivortices. We show that the transport in SC-FM bilayer is highly...

  8. acid bilayers observed: Topics by E-print Network

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

    double dots can be effectively tuned from weak to strong regime by both the in-plane plunger gates and back gate. All the relevant energy scales and parameters of the bilayer...

  9. Water permeation through stratum corneum lipid bilayers from atomistic simulations

    E-Print Network [OSTI]

    Chinmay Das; Peter D. Olmsted; Massimo G. Noro

    2009-07-09T23:59:59.000Z

    Stratum corneum, the outermost layer of skin, consists of keratin filled rigid non-viable corneocyte cells surrounded by multilayers of lipids. The lipid layer is responsible for the barrier properties of the skin. We calculate the excess chemical potential and diffusivity of water as a function of depth in lipid bilayers with compositions representative of the stratum corneum using atomistic molecular dynamics simulations. The maximum in the excess free energy of water inside the lipid bilayers is found to be twice that of water in phospholipid bilayers at the same temperature. Permeability, which decreases exponentially with the free energy barrier, is reduced by several orders of magnitude as compared to with phospholipid bilayers. The average time it takes for a water molecule to cross the bilayer is calculated by solving the Smoluchowski equation in presence of the free energy barrier. For a bilayer composed of a 2:2:1 molar ratio of ceramide NS 24:0, cholesterol and free fatty acid 24:0 at 300K, we estimate the permeability P=3.7e-9 cm/s and the average crossing time \\tau_{av}=0.69 ms. The permeability is about 30 times smaller than existing experimental results on mammalian skin sections.

  10. Final Technical Report: Grain Boundary Complexions and Transitions in Doped Silicon

    SciTech Connect (OSTI)

    Jian Luo

    2012-10-15T23:59:59.000Z

    This four-year research project has advanced the fundamental knowledge of grain boundary (GB) complexions (i.e., "two-dimensional interfacial phases") and associated GB "phase" transitions in several grounds. First, a bilayer interfacial phase, which had been directly observed by microscopy only in complex ceramic systems in prior studies, has been identified in simpler systems such as Au-doped Si and Bi-doped Ni in this study, where the interpretations of the their formation mechanisms and microscopic images are less equivocal. Second, convincing evidence for the existence of a first-order GB transition from a nominally "clean" GB to a bilayer adsorption interfacial phase has been revealed for Au-doped Si; the confirmation of the first-order nature of interfacial transitions at GBs, which was rare in prior studies, is scientifically significant and technologically important. Third, the bilayer interfacial phase discovered in Bi-doped Ni has been found to be the cause of the mysterious liquid metal embrittlement phenomenon in this system; the exact atomic level mechanism of this phenomenon has puzzled the materials and physics communities for over a century. Finally, significant advancements have been made to establish phenomenological thermodynamic models for GB complexions and transitions. Since GB complexions can control the transport, mechanical and physical properties of a broad range of metallic and ceramic materials, the fundamental knowledge generated by this project can have broad impacts on materials design in general. In this regard, understanding and controlling GB phase behaviors (complexions and transitions) can be an important component for the "Materials Genome" project.

  11. The ground state construction of bilayer graphene

    E-Print Network [OSTI]

    Alessandro Giuliani; Ian Jauslin

    2015-07-22T23:59:59.000Z

    We consider a model of half-filled bilayer graphene, in which the three dominant Slonczewski-Weiss-McClure hopping parameters are retained, in the presence of short range interactions. Under a smallness assumption on the interaction strength $U$ as well as on the inter-layer hopping $\\epsilon$, we construct the ground state in the thermodynamic limit, and prove its analyticity in $U$, uniformly in $\\epsilon$. The interacting Fermi surface is degenerate, and consists of eight Fermi points, two of which are protected by symmetries, while the locations of the other six are renormalized by the interaction, and the effective dispersion relation at the Fermi points is conical. The construction reveals the presence of different energy regimes, where the effective behavior of correlation functions changes qualitatively. The analysis of the crossover between regimes plays an important role in the proof of analyticity and in the uniform control of the radius of convergence. The proof is based on a rigorous implementation of fermionic renormalization group methods, including determinant estimates for the renormalized expansion.

  12. Green exciplex emission from a bilayer light-emitting diode containing a rare earth ternary complex

    E-Print Network [OSTI]

    Huang, Yanyi

    Green exciplex emission from a bilayer light-emitting diode containing a rare earth ternary complex form 18 October 2001 Abstract A bilayer organic light-emitting diode using a blue-fluorescent yttrium

  13. Can adding oil control domain formation in binary amphiphile bilayers?

    E-Print Network [OSTI]

    M. J. Greenall; C. M. Marques

    2014-06-12T23:59:59.000Z

    Bilayers formed of two species of amphiphile of different chain lengths may segregate into thinner and thicker domains composed predominantly of the respective species. Using a coarse-grained mean-field model, we investigate how mixing oil with the amphiphiles affects the structure and thickness of the bilayer at and on either side of the boundary between two neighbouring domains. In particular, we find that oil molecules whose chain length is close to that of the shorter amphiphiles segregate to the thicker domain. This smooths the surface of the hydrophobic bilayer core on this side of the boundary, reducing its area and curvature and their associated free-energy penalties. The smoothing effect is weaker for oil molecules that are shorter or longer than this optimum value: short molecules spread evenly through the bilayer, while long molecules swell the thicker domain, increasing the surface area and curvature of the bilayer core in the interfacial region. Our results show that adding an appropriate oil could make the formation of domain boundaries more or less favourable, raising the possibility of controlling the domain size distribution.

  14. Direct Detection of Membrane Channels from Gels Using Water-in-Oil Droplet Bilayers

    E-Print Network [OSTI]

    Wallace, Mark

    Direct Detection of Membrane Channels from Gels Using Water-in-Oil Droplet Bilayers Andrew J. Heron lipid bilayers serve as simplified models of biological membranes and are widely used for the electrical in many situations. Alternative emulsion-based approaches to forming bilayers have also been reported,15

  15. hal-00276997,version1-5May2008 Raman spectra of misoriented bilayer graphene

    E-Print Network [OSTI]

    hal-00276997,version1-5May2008 Raman spectra of misoriented bilayer graphene P. Poncharal1 , A layer graphene with a bilayer in which the two layers are arbitrarily misoriented. The profiles of the 2 of the electronic structures of single layer graphene and misoriented bilayer graphene. Another new aspect

  16. Enhanced residual entropy in high-density nanoconfined bilayer ice

    E-Print Network [OSTI]

    Fabiano Corsetti; Jon Zubeltzu; Emilio Artacho

    2015-06-15T23:59:59.000Z

    A novel kind of crystal order in high-density nanoconfined bilayer ice is proposed from molecular dynamics and density-functional theory simulations. A first-order transition is observed between a low-temperature proton-ordered solid and a high-temperature proton-disordered solid. The latter is shown to possess crystalline order for the oxygen positions, arranged on a close-packed triangular lattice with AA stacking. Uniquely amongst the ice phases, the triangular bilayer is characterized by two levels of disorder (for the bonding network and for the protons) which results in a residual entropy twice that of bulk ice.

  17. Electronic band structure of magnetic bilayer graphene superlattices

    SciTech Connect (OSTI)

    Pham, C. Huy; Nguyen, T. Thuong [Theoretical and Computational Physics Department, Institute of Physics, VAST, 10 Dao Tan, Ba Dinh Distr., Hanoi 10000 (Viet Nam); SISSA/International School for Advanced Study, Via Bonomea 265, I-34136 Trieste (Italy); Nguyen, V. Lien, E-mail: nvlien@iop.vast.ac.vn [Theoretical and Computational Physics Department, Institute of Physics, VAST, 10 Dao Tan, Ba Dinh Distr., Hanoi 10000 (Viet Nam); Institute for Bio-Medical Physics, 109A Pasteur, 1st Distr., Hochiminh City (Viet Nam)

    2014-09-28T23:59:59.000Z

    Electronic band structure of the bilayer graphene superlattices with ?-function magnetic barriers and zero average magnetic flux is studied within the four-band continuum model, using the transfer matrix method. The periodic magnetic potential effects on the zero-energy touching point between the lowest conduction and the highest valence minibands of pristine bilayer graphene are exactly analyzed. Magnetic potential is shown also to generate the finite-energy touching points between higher minibands at the edges of Brillouin zone. The positions of these points and the related dispersions are determined in the case of symmetric potentials.

  18. Graphene Monolayer Rotation on Ni(111) Facilities Bilayer Graphene Growth

    SciTech Connect (OSTI)

    Batzill M.; Sutter P.; Dahal, A.; Addou, R.

    2012-06-11T23:59:59.000Z

    Synthesis of bilayer graphene by chemical vapor deposition is of importance for graphene-based field effect devices. Here, we demonstrate that bilayer graphene preferentially grows by carbon-segregation under graphene sheets that are rotated relative to a Ni(111) substrate. Rotated graphene monolayer films can be synthesized at growth temperatures above 650 C on a Ni(111) thin-film. The segregated second graphene layer is in registry with the Ni(111) substrate and this suppresses further C-segregation, effectively self-limiting graphene formation to two layers.

  19. Surface tension in bilayer membranes with fixed projected area

    E-Print Network [OSTI]

    Alberto Imparato

    2006-04-05T23:59:59.000Z

    We study the elastic response of bilayer membranes with fixed projected area to both stretching and shape deformations. A surface tension is associated to each of these deformations. By using model amphiphilic membranes and computer simulations, we are able to observe both the types of deformation, and thus, both the surface tensions, related to each type of deformation, are measured for the same system. These surface tensions are found to assume different values in the same bilayer membrane: in particular they vanish for different values of the projected area. We introduce a simple theory which relates the two quantities and successfully apply it to the data obtained with computer simulations.

  20. Isoelectronic co-doping

    DOE Patents [OSTI]

    Mascarenhas, Angelo

    2004-11-09T23:59:59.000Z

    Isoelectronic co-doping of semiconductor compounds and alloys with deep acceptors and deep donors is used to decrease bandgap, to increase concentration of the dopant constituents in the resulting alloys, and to increase carrier mobilities lifetimes. Group III-V compounds and alloys, such as GaAs and GaP, are isoelectronically co-doped with, for example, N and Bi, to customize solar cells, thermal voltaic cells, light emitting diodes, photodetectors, and lasers on GaP, InP, GaAs, Ge, and Si substrates. Isoelectronically co-doped Group II-VI compounds and alloys are also included.

  1. STABLE HIGH CONDUCTIVITY BILAYERED ELECTROLYTES FOR LOW TEMPERATURE SOLID OXIDE FUEL CELLS

    SciTech Connect (OSTI)

    Eric D. Wachsman; Keith L. Duncan

    2002-03-31T23:59:59.000Z

    Solid oxide fuel cells (SOFCs) are the future of energy production in America. They offer great promise as a clean and efficient process for directly converting chemical energy to electricity while providing significant environmental benefits (they produce negligible hydrocarbons, CO, or NO{sub x} and, as a result of their high efficiency, produce about one-third less CO{sub 2} per kilowatt hour than internal combustion engines). Unfortunately, the current SOFC technology, based on a stabilized zirconia electrolyte, must operate in the region of 1000 C to avoid unacceptably high ohmic losses. These high temperatures demand (a) specialized (expensive) materials for the fuel cell interconnects and insulation, (b) time to heat up to the operating temperature and (c) energy input to arrive at the operating temperature. Therefore, if fuel cells could be designed to give a reasonable power output at low to intermediate temperatures tremendous benefits may be accrued. At low temperatures, in particular, it becomes feasible to use ferritic steel for interconnects instead of expensive and brittle ceramic materials such as those based on LaCrO{sub 3}. In addition, sealing the fuel cell becomes easier and more reliable; rapid startup is facilitated; thermal stresses (e.g., those caused by thermal expansion mismatches) are reduced; radiative losses ({approx}T{sup 4}) become minimal; electrode sintering becomes negligible and (due to a smaller thermodynamic penalty) the SOFC operating cycle (heating from ambient) would be more efficient. Combined, all these improvements further result in reduced initial and operating costs. The problem is, at lower temperatures the conductivity of the conventional stabilized zirconia electrolyte decreases to the point where it cannot supply electrical current efficiently to an external load. The primary objectives of the proposed research is to develop a stable high conductivity (> 0.05 S cm{sup -1} at {le} 550 C) electrolyte for lower temperature SOFCs. This objective is specifically directed toward meeting the lowest (and most difficult) temperature criteria for the 21st Century Fuel Cell Program. Meeting this objective provides a potential for future transportation applications of SOFCs, where their ability to directly use hydrocarbon fuels could permit refueling within the existing transportation infrastructure. In order to meet this objective we are developing a functionally gradient bilayer electrolyte comprised of a layer of erbia-stabilized bismuth oxide (ESB) on the oxidizing side and a layer of SDC or GDC on the reducing side, see Fig. 1. Bismuth oxide and doped ceria are among the highest ionic conducting electrolytes and in fact bismuth oxide based electrolytes are the only known solid oxide electrolytes to have an ionic conductivity that meets the program conductivity goal. In this arrangement, the ceria layer protects the bismuth oxide layer from decomposing by shielding it from very low P{sub O{sub 2}}'s and the ESB layer serves to block electronic flux through the electrolyte. This arrangement has two significant advantages over the YSZ/SDC bilayers investigated by others [1, 2]. The first advantage is that SDC is conductive enough to serve as an intermediate temperature SOFC electrolyte. Moreover, ESB is conductive enough to serve as a low temperature electrolyte. Consequently, at worst an SDC/ESB bilayered SOFC should have the conductivity of SDC but with improved efficiency due to the electronic flux barrier provided by ESB. The second advantage is that small (dopant) concentrations of SDC in ESB or ESB in SDC, have been found to have conductivities comparable to the host lattice [3, 4]. Therefore, if solid solutioning occurs at the SDC-ESB interface, it should not be detrimental to the performance of the bilayer. In contrast, solid solutions of SDC and YSZ have been found to be significantly less conductive than SDC or YSZ. Thus, it bears emphasizing that, at this time, only SDC/ESB electrolytes have potential in low temperature SOFC applications.

  2. The component groups structure of DPPC bilayers obtained by specular neutron reflectometry

    E-Print Network [OSTI]

    Michal Beli?ka; Yuri Gerelli; Norbert Ku?erka; Giovanna Fragneto

    2014-12-16T23:59:59.000Z

    Specular neutron reflectometry (SNR) was measured on a system of a floating bilayer consisting of 1,2-dipalmitoyl-d62-\\textit{sn}-glycero-3-phosphocholine (d62-diC16:0PC) deposited over a 1,2-dibehenoyl-\\textit{sn}-glycero-3-phosphocholine (diC22:0PC) bilayer at 25 and 55 {\\deg}C. The internal structure of lipid bilayers was described by a one dimensional scattering length density profile (SLDP) model, originally developed for the evaluation of small angle scattering data. The corresponding model reflectivity curves successfully describe the experimental reflectivity curves of a supported bilayer in the gel phase and a system of a floating bilayer in the liquid crystalline phase. The reflectivity data from the supported bilayer were evaluated individually and served further as an input by the data treatment of floating bilayer reflectivity curves. The results yield internal structure of a deposited and floating bilayer on the level of component groups of lipid molecules. The obtained structure of the floating d62-diC16:0PC bilayer displays high resemblance to the bilayer structure in the form of unilamellar vesicles, however, simultaneously it shows rate of fluctuations in comparison to unilamellar vesicle bilayers.

  3. Selective Monosaccharide Transport through Lipid Bilayers Using Boronic Acid Carriers

    E-Print Network [OSTI]

    Smith, Bradley D.

    Selective Monosaccharide Transport through Lipid Bilayers Using Boronic Acid Carriers Pamela R-one boronic acids were studied for their ability to transport saccharides in and out of liposomes. The rates transport. The order of transport selectivity was sorbitol > fructose > glucose. The disaccharides maltose

  4. Molecular friction and epitactic coupling between monolayers in supported bilayers

    E-Print Network [OSTI]

    Boyer, Edmond

    1535 Molecular friction and epitactic coupling between monolayers in supported bilayers R. Merkel un substrat de membrane couplée (Evans et Sackmann, 1988), on détermine la friction moléculaire coefficients de friction entre les couches en fixant la couche mononucléaire proximale sur le substrat par des

  5. Registered and antiregistered phase separation of mixed amphiphilic bilayers

    E-Print Network [OSTI]

    John J. Williamson; Peter D. Olmsted

    2015-03-12T23:59:59.000Z

    We derive a mean-field free energy for the phase behaviour of coupled bilayer leaflets, which is implicated in cellular processes and important to the design of artificial membranes. Our model accounts for amphiphile-level structural features, particularly hydrophobic mismatch, which promotes antiregistration (AR), in competition with the `direct' trans-midplane coupling usually studied, promoting registration (R). We show that the phase diagram of coupled leaflets allows multiple \\textit{metastable} coexistences, then illustrate the kinetic implications with a detailed study of a bilayer of equimolar overall composition. For approximate parameters estimated to apply to phospholipids, equilibrium coexistence is typically registered, but metastable antiregistered phases can be kinetically favoured by hydrophobic mismatch. Thus a bilayer in the spinodal region can require nucleation to equilibrate, in a novel manifestation of Ostwald's `rule of stages'. Our results provide a framework for understanding disparate existing observations, elucidating a subtle competition of couplings, and a key role for phase transition kinetics in bilayer phase behaviour.

  6. Topological insulating phases in mono and bilayer graphene

    E-Print Network [OSTI]

    Alberto Cortijo; Adolfo G. Grushin; Maria A. H. Vozmediano

    2010-11-20T23:59:59.000Z

    We analyze the influence of different quadratic interactions giving rise to time reversal invariant topological insulating phases in mono and bilayer graphene. We make use of the effective action formalism to determine the dependence of the Chern Simons coefficient on the different interactions.

  7. Berry phase and pseudospin winding number in bilayer graphene

    E-Print Network [OSTI]

    Marzari, Nicola

    Ever since the novel quantum Hall effect in bilayer graphene was discovered, and explained by a Berry phase of 2? [ K. S. Novoselov et al. Nat. Phys. 2 177 (2006)], it has been widely accepted that the low-energy electronic ...

  8. Josephson inplane and tunneling currents in bilayer quantum Hall system

    SciTech Connect (OSTI)

    Ezawa, Z. F. [Nishina Center, RIKEN, Saitama 351-0198 (Japan); Tsitsishvili, G. [Georgia Department of Physics, Tbilisi State University, Tbilisi 0179 (Georgia); Sawada, A. [Research Center for Low Temperature and Materials Sciences, Kyoto University, Kyoto 606-8501 (Japan)

    2013-12-04T23:59:59.000Z

    A Bose-Einstein condensation is formed by composite bosons in the quantum Hall state. A composite boson carries the fundamental charge (–e). We investigate Josephson tunneling of such charges in the bilayer quantum Hall system at the total filling ? = 1. We show the existence of the critical current for the tunneling current to be coherent and dissipationless in tunneling experiments with various geometries.

  9. Registered and antiregistered phase separation of mixed amphiphilic bilayers

    E-Print Network [OSTI]

    John J. Williamson; Peter D. Olmsted

    2015-04-08T23:59:59.000Z

    We derive a mean-field free energy for the phase behaviour of coupled bilayer leaflets, which is implicated in cellular processes and important to the design of artificial membranes. Our model accounts for amphiphile-level structural features, particularly hydrophobic mismatch, which promotes antiregistration (AR), in competition with the `direct' trans-midplane coupling usually studied, promoting registration (R). We show that the phase diagram of coupled leaflets allows multiple \\textit{metastable} coexistences, then illustrate the kinetic implications with a detailed study of a bilayer of equimolar overall composition. For approximate parameters estimated to apply to phospholipids, equilibrium coexistence is typically registered, but metastable antiregistered phases can be kinetically favoured by hydrophobic mismatch. Thus a bilayer in the spinodal region can require nucleation to equilibrate, in a novel manifestation of Ostwald's `rule of stages'. Our results provide a framework for understanding disparate existing observations, elucidating a subtle competition of couplings, and a key role for phase transition kinetics in bilayer phase behaviour.

  10. Hierarchy of fillings for FQHE in monolayer and in bilayer graphene: Explanation of $?=-\\frac{1}{2}$ fractional quantum Hall state in bilayer graphene

    E-Print Network [OSTI]

    Janusz Jacak; Lucjan Jacak

    2015-02-04T23:59:59.000Z

    The commensurability condition is applied to determine the hierarchy of fractional fillings of Landau levels in monolayer and bilayer graphene. The filling rates for FQHE in graphene are found and illustrated in the first three Landau levels. The good agreement with the experimental data is achieved. The presence of even denominator filling fractions in the hierarchy for FQHE in bilayer graphene is explained.

  11. Double Barriers and Magnetic Field in Bilayer Graphene

    E-Print Network [OSTI]

    Ilham Redouani; Ahmed Jellal; Hocine Bahlouli

    2015-05-21T23:59:59.000Z

    We study the transmission probability in an AB-stacked bilayer graphene of Dirac fermions scattered by a double barrier structure in the presence of a magnetic field. We take into account the full four bands of the energy spectrum and use the boundary conditions to determine the transmission probability. Our numerical results show that for energies higher than the interlayer coupling, four ways for transmission probabilities are possible while for energies less than the height of the barrier, Dirac fermions exhibits transmission resonances and only one transmission channel is available. We show that, for AB-stacked bilayer graphene, there is no Klein tunneling at normal incident. We find that the transmission displays sharp peaks inside the transmission gap around the Dirac point within the barrier regions while they are absent around the Dirac point in the well region. The effect of the magnetic field, interlayer electrostatic potential and various barrier geometry parameters on the transmission probabilities are also discussed.

  12. Band Tunneling through Double Barrier in Bilayer Graphene

    E-Print Network [OSTI]

    Hasan A. Alshehab; Hocine Bahlouli; Abderrahim El Mouhafid; Ahmed Jellal

    2014-01-20T23:59:59.000Z

    By taking into account the full four band energy spectrum, we calculate the transmission probability and conductance of electrons across symmetric and asymmetric double potential barrier with a confined interlayer potential difference in bilayer graphene. For energies less than the interlayer coupling \\gamma_{1}, E \\gamma_{1}, we obtain four possible ways for transmission resulting from the two propagating modes. We compute the associated transmission probabilities as well as their contribution to the conductance, study the effect of the double barrier geometry.

  13. Diamondization of Graphene and Graphene-BN Bilayers: Chemical Functionalization and Electronic Structure Engineering

    E-Print Network [OSTI]

    Yuan, Long; Yang, Jinlong; Hou, Jian Guo

    2011-01-01T23:59:59.000Z

    In this article, based on first-principles calculations, we systematically study functionalization induced diamonization of graphene bilayer and graphene-BN hybrid bilayer. With single-side functionalization, the diamondized structures are magnetic semiconductor. Interestingly, if both sides of the bilayer are functionalized, diamondization becomes spontaneous without a barrier. On the other hand, when the bottom layer of the bilayer graphene is replaced by a single hexagonal BN layer, the diamondized structure becomes nonmagnetic metal. The tunable electronic and magnetic properties pave new avenues to construct graphene-based electronics and spintronics devices.

  14. antibacterial copper-nickel bilayers: Topics by E-print Network

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

    A. Haselwandter; Rob Phillips 2011-06-10 5 Transverse electric plasmons in bilayer graphene MIT - DSpace Summary: We predict the existence of transverse electric (TE) plasmons...

  15. Doped zinc oxide microspheres

    DOE Patents [OSTI]

    Arnold, W.D. Jr.; Bond, W.D.; Lauf, R.J.

    1993-12-14T23:59:59.000Z

    A new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel. 4 figures.

  16. Development of a Microfluidic Device for Synthesis of Lipid Bi-Layer In-Situ

    E-Print Network [OSTI]

    Banneyake, Bm U.

    2010-01-14T23:59:59.000Z

    and result in unstable bi-layers having a short lifetime. In this investigation a novel microfluidic device and a method for artificial synthesis of lipid bi-layer in-situ are explored. In the proposed method, lipid trapped at an aperture on a Teflon sheet...

  17. Hierarchy of fillings for FQHE in monolayer and in bilayer graphene: Explanation of $\

    E-Print Network [OSTI]

    Jacak, Janusz

    2015-01-01T23:59:59.000Z

    The commensurability condition is applied to determine the hierarchy of fractional fillings of Landau levels in monolayer and bilayer graphene. The filling rates for FQHE in graphene are found and illustrated in the first three Landau levels. The good agreement with the experimental data is achieved. The presence of even denominator filling fractions in the hierarchy for FQHE in bilayer graphene is explained.

  18. Polymer-Cushioned Bilayers. I. A Structural Study of Various Preparation Methods Using Neutron Reflectometry

    E-Print Network [OSTI]

    Wong, Joyce

    Polymer-Cushioned Bilayers. I. A Structural Study of Various Preparation Methods Using Neutron of preparing polymer-cushioned lipid bilayers. Four different techniques to deposit adsorption onto a previously dried polymer layer; 2) vesicle adsorption onto a bare substrate, followed

  19. Lipid Bilayer Structure Determined by the Simultaneous Analysis of Neutron and X-Ray Scattering Data

    E-Print Network [OSTI]

    Nagle, John F.

    Lipid Bilayer Structure Determined by the Simultaneous Analysis of Neutron and X-Ray Scattering) and dipalmitoylphosphatidylcholine (DPPC) bilayers by simultaneously analyzing x-ray and neutron scattering data. The neutron data electron and neutron scattering density profiles. A key result of the analysis is the molecular surface

  20. Title: Electron-Hole Asymmetric Integer and Fractional Quantum Hall Effect in Bilayer Graphene

    E-Print Network [OSTI]

    Yacoby, Amir

    Title: Electron-Hole Asymmetric Integer and Fractional Quantum Hall Effect in Bilayer Graphene graphene is predicted to pro- duce novel and tunable FQH ground states. Here we present local electronic compressibility measurements of the FQH effect in the lowest Landau level of bilayer graphene. We observe

  1. Protein Separation and Label-Free Detection on Supported Lipid Bilayers

    E-Print Network [OSTI]

    Liu, Chunming

    2012-10-19T23:59:59.000Z

    of Health, which provided the funding. Finally, thanks to my mother and father for their encouragement. vi NOMENCLATURE SLB Supported Lipid Bilayer SUV Small Uni-lamellar Vesicle FRAP Fluorescence Recovery After Photobleaching PDMS... Patterning and PDMS Stamping ............. 5 Electrophoresis Flow Cell Device .................................................. 7 II PROTEIN SEPARATION BY ELECTROPHORETIC- ELECTROOSMOTIC FOCUSING ON SUPPORTED LIPID BILAYER...

  2. Bilayer thickness effects on nanoindentation behavior of Ag/Ni multilayers

    E-Print Network [OSTI]

    Hong, Soon Hyung

    by nanoindentation hardness and creep tests. The hardness increased with decreasing bilayer thickness, although of nanoindentation creep tests on Ag/Ni nanomultilayers with various bilayer thicknesses. Multilayered Ag/Ni films thickness. A nanoindentation creep test was used to study the creep behavior of nano- scale multilayers

  3. Carrier scattering, mobilities, and electrostatic potential in monolayer, bilayer, and trilayer graphene

    E-Print Network [OSTI]

    Perebeinos, Vasili

    graphene Wenjuan Zhu,* Vasili Perebeinos, Marcus Freitag, and Phaedon Avouris IBM Thomas J. Watson Research mobility in monolayer, bilayer, and trilayer graphene has been systematically studied. We found that as the carrier density increases, the mobility decreases for monolayer graphene, while it increases for bilayer

  4. Size-dependent ultrafast structural dynamics inside phospholipid vesicle bilayers measured with 2D IR

    E-Print Network [OSTI]

    Fayer, Michael D.

    Size-dependent ultrafast structural dynamics inside phospholipid vesicle bilayers measured with 2D 25, 2013) The ultrafast structural dynamics inside the bilayers of dilauroyl- phosphatidylcholine was used as a vibrational probe and provided information on spectral diffusion (structural dynam- ics

  5. Exchange bias and blocking temperature distribution of Fe-film/CoO-nanoparticle hybrid bilayers

    E-Print Network [OSTI]

    Krishnan, Kannan M.

    relaxation in a Fe-film/CoO-nanoparticle hybrid system Appl. Phys. Lett. 101, 132401 (2012); 10 anisotropy energy per unit volume and V is the grain volume. Therefore, hybrid EB bilayers with the AF layer beExchange bias and blocking temperature distribution of Fe-film/CoO-nanoparticle hybrid bilayers Wei

  6. Production of microporous aluminum oxide electrodes as supports for tethered lipid bilayers of large surface area.

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Production of microporous aluminum oxide electrodes as supports for tethered lipid bilayers.Bourdillon@utc.fr Abstract A composite electrode made by association of gold and porous aluminum oxide has been used aluminum oxide; phospholipid bilayer; two-dimensional electrochemistry; ubiquinone lateral mobility. 1

  7. Critical adsorption controls translocation of polymer chains through lipid bilayers and permeation of solvent

    E-Print Network [OSTI]

    Jens-Uwe Sommer; Marco Werner; Vladimir A. Baulin

    2012-05-21T23:59:59.000Z

    Monte Carlo simulations using an explicit solvent model indicate a new pathway for translocation of a polymer chain through a lipid bilayer. We consider a polymer chain composed of repeat units with a given hydrophobicity and a coarse-grained model of a lipid bilayer in the self-organized liquid state. By varying the degree of hydrophobicity the chain undergoes an adsorption transition with respect to the lipid bilayer. Close to the transition point, at a properly balanced hydrophobicity of the chain, the membrane becomes transparent with respect to the chain. At the same time the solvent permeability of the bilayer is strongly increased in the region close to adsorbed chain. Our results indicate that the critical point of adsorption of the polymer chain interacting with the fluctuating lipid bilayer could play a key role for the translocation of molecules though biological membranes.

  8. Specific heat of twisted bilayer graphene: Engineering phonons by atomic plane rotations

    SciTech Connect (OSTI)

    Nika, Denis L. [E. Pokatilov Laboratory of Physics and Engineering of Nanomaterials, Department of Physics and Engineering, Moldova State University, Chisinau MD-2009, Republic of Moldova (Moldova, Republic of); Nano-Device Laboratory, Department of Electrical Engineering and Materials Science and Engineering Program, Bourns College of Engineering, University of California—Riverside, Riverside, California, 92521 (United States); Cocemasov, Alexandr I. [E. Pokatilov Laboratory of Physics and Engineering of Nanomaterials, Department of Physics and Engineering, Moldova State University, Chisinau MD-2009, Republic of Moldova (Moldova, Republic of); Balandin, Alexander A., E-mail: balandin@ee.ucr.edu [Nano-Device Laboratory, Department of Electrical Engineering and Materials Science and Engineering Program, Bourns College of Engineering, University of California—Riverside, Riverside, California, 92521 (United States)

    2014-07-21T23:59:59.000Z

    We have studied the phonon specific heat in single-layer, bilayer, and twisted bilayer graphene. The calculations were performed using the Born-von Karman model of lattice dynamics for intralayer atomic interactions and spherically symmetric interatomic potential for interlayer interactions. We found that at temperature T?bilayer graphene, and n?=?1.3 for the twisted bilayer graphene. The phonon specific heat reveals an intriguing dependence on the twist angle in bilayer graphene, which is particularly pronounced at low temperature. The results suggest a possibility of phonon engineering of thermal properties of layered materials by twisting the atomic planes.

  9. Interdiffusion at the bilayer polymer interface: Evidence for reptation. [NEUTRONS

    SciTech Connect (OSTI)

    Felcher, G.P.; Karim, A. (Argonne National Lab., IL (USA)); Russell, T.P. (IBM Research Div., San Jose, CA (USA). Almaden Research Center)

    1990-06-01T23:59:59.000Z

    Neutron reflection is used to study the interdiffusion in equal molecular weight polystyrene bilayer melts with a spatial resolution of 1nm. Interfacial widths and concentration profiles at the bilayer interface are obtained for annealing times up to and beyond the time (reptation time, {tau}{sub d}) in which the molecule has moved by its own length. For annealing times t < {tau}{sub d}, the reptation model predicts a mean square displacement of monomers whose time evolution is a power law. The detailed profile is expected to exhibit a discontinuity (sharp gradient) of density at the interface between the two polymers. For relatively light weight polymers of M {approx} 233,000, the mean square displacements of monomers is in general agreement with reptation predictions; the discontinuity at the interface is only observed when the molecular weights are large, M {approx} 1,000,000. The discontinuity is present even for low concentrations of the deuterated polymer where isotopic slowing down effects are negligible, thus confirming the sharp gradient as being due to reptation. 19 refs., 5 figs.

  10. The lipid bilayer at the mesoscale: a physical continuum model

    E-Print Network [OSTI]

    Phillip L. Wilson; Huaxiong Huang; Shu Takagi

    2008-02-26T23:59:59.000Z

    We study a continuum model of the lipid bilayer based on minimizing the free energy of a mixture of water and lipid molecules. This paper extends previous work by Blom & Peletier (2004) in the following ways. (a) It formulates a more physical model of the hydrophobic effect to facilitate connections with microscale simulations. (b) It clarifies the meaning of the model parameters. (c) It outlines a method for determining parameter values so that physically-realistic bilayer density profiles can be obtained, for example for use in macroscale simulations. Points (a)-(c) suggest that the model has potential to robustly connect some micro- and macroscale levels of multiscale blood flow simulations. The mathematical modelling in point (a) is based upon a consideration of the underlying physics of inter-molecular forces. The governing equations thus obtained are minimized by gradient flows via a novel numerical approach; this enables point (b). The numerical results are shown to behave physically in terms of the effect of background concentration, in contrast to the earlier model which is shown here to not display the expected behaviour. A "short-tail" approximation of the lipid molecules also gives an analytical tool which yields critical values of some parameters under certain conditions. Point (c) involves the first quantitative comparison of the numerical data with physical experimental results.

  11. The Molecular Structure of a Phosphatidylserine Bilayer Determined by Scattering and Molecular Dynamics Simulations

    SciTech Connect (OSTI)

    Pan, Jianjun [University of South Florida, Tampa (USF)] [University of South Florida, Tampa (USF); Cheng, Xiaolin [ORNL] [ORNL; Monticelli, Luca [Institut National de la Santé et de la Recherche Médicale (INSERM) and INTS, France] [Institut National de la Santé et de la Recherche Médicale (INSERM) and INTS, France; Heberle, Frederick A [ORNL] [ORNL; Kucerka, Norbert [Atomic Energy of Canada Limited (AECL), Canadian Neutron Beam Centre (CNBC) and Comenius University,] [Atomic Energy of Canada Limited (AECL), Canadian Neutron Beam Centre (CNBC) and Comenius University,; Tieleman, D. Peter [University of Calgary, ALberta, Canada] [University of Calgary, ALberta, Canada; Katsaras, John [ORNL] [ORNL

    2014-01-01T23:59:59.000Z

    Phosphatidylserine (PS) lipids play essential roles in biological processes, including enzyme activation and apoptosis. We report on the molecular structure and atomic scale interactions of a fluid bilayer composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylserine (POPS). A scattering density profile model, aided by molecular dynamics (MD) simulations, was developed to jointly refine different contrast small-angle neutron and X-ray scattering data, which yielded a lipid area of 62.7 A2 at 25 C. MD simulations with POPS lipid area constrained at different values were also performed using all-atom and aliphatic united-atom models. The optimal simulated bilayer was obtained using a model-free comparison approach. Examination of the simulated bilayer, which agrees best with the experimental scattering data, reveals a preferential interaction between Na+ ions and the terminal serine and phosphate moieties. Long-range inter-lipid interactions were identified, primarily between the positively charged ammonium, and the negatively charged carboxylic and phosphate oxygens. The area compressibility modulus KA of the POPS bilayer was derived by quantifying lipid area as a function of surface tension from area-constrained MD simulations. It was found that POPS bilayers possess a much larger KA than that of neutral phosphatidylcholine lipid bilayers. We propose that the unique molecular features of POPS bilayers may play an important role in certain physiological functions.

  12. Corrugation of Phase-Separated Lipid Bilayers Supported by Nanoporous Silica Xerogel Surfaces

    SciTech Connect (OSTI)

    Goksu, E I; Nellis, B A; Lin, W; Satcher Jr., J H; Groves, J T; Risbud, S H; Longo, M L

    2008-10-30T23:59:59.000Z

    Lipid bilayers supported by substrates with nanometer-scale surface corrugations holds interest in understanding both nanoparticle-membrane interactions and the challenges of constructing models of cell membranes on surfaces with desirable properties, e.g. porosity. Here, we successfully form a two-phase (gel-fluid) lipid bilayer supported by nanoporous silica xerogel. Surface topology, diffusion, and lipid density in comparison to mica-supported lipid bilayers were characterized by AFM, FRAP, FCS, and quantitative fluorescence microscopy, respectively. We found that the two-phase lipid bilayer follows the xerogel surface contours. The corrugation imparted on the lipid bilayer results in a lipid density that is twice that on a flat mica surface. In direct agreement with the doubling of actual bilayer area in a projected area, we find that the lateral diffusion coefficient (D) of lipids on xerogel ({approx}1.7 {micro}m{sup 2}/s) is predictably lower than on mica ({approx}4.1 {micro}m{sup 2}/s) by both FRAP and FCS techniques. Furthermore, the gel-phase domains on xerogel compared to mica were larger and less numerous. Overall, our results suggest the presence of a relatively defect-free continuous two-phase bilayer that penetrates approximately midway into the first layer of {approx}50 nm xerogel beads.

  13. Ag and Au atoms intercalated in bilayer heterostructures of transition metal dichalcogenides and graphene

    SciTech Connect (OSTI)

    Iyikanat, F., E-mail: fadiliyikanat@iyte.edu.tr; Senger, R. T. [Department of Physics, Izmir Institute of Technology, 35430 Izmir (Turkey); Sahin, H., E-mail: hasan.sahin@uantwerpen.be; Peeters, F. M. [Department of Physics, University of Antwerp, 2610 Antwerp (Belgium)

    2014-09-01T23:59:59.000Z

    The diffusive motion of metal nanoparticles Au and Ag on monolayer and between bilayer heterostructures of transition metal dichalcogenides and graphene are investigated in the framework of density functional theory. We found that the minimum energy barriers for diffusion and the possibility of cluster formation depend strongly on both the type of nanoparticle and the type of monolayers and bilayers. Moreover, the tendency to form clusters of Ag and Au can be tuned by creating various bilayers. Tunability of the diffusion characteristics of adatoms in van der Waals heterostructures holds promise for controllable growth of nanostructures.

  14. Passivating overcoat bilayer for multilayer reflective coatings for extreme ultraviolet lithography

    DOE Patents [OSTI]

    Montcalm, Claude (Livermore, CA); Stearns, Daniel G. (Los Altos, CA); Vernon, Stephen P. (Pleasanton, CA)

    1999-01-01T23:59:59.000Z

    A passivating overcoat bilayer is used for multilayer reflective coatings for extreme ultraviolet (EUV) or soft x-ray applications to prevent oxidation and corrosion of the multilayer coating, thereby improving the EUV optical performance. The overcoat bilayer comprises a layer of silicon or beryllium underneath at least one top layer of an elemental or a compound material that resists oxidation and corrosion. Materials for the top layer include carbon, palladium, carbides, borides, nitrides, and oxides. The thicknesses of the two layers that make up the overcoat bilayer are optimized to produce the highest reflectance at the wavelength range of operation. Protective overcoat systems comprising three or more layers are also possible.

  15. Nitrogen-doped Graphene and Its Electrochemical Applications...

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

    doped Graphene and Its Electrochemical Applications. Nitrogen-doped Graphene and Its Electrochemical Applications. Abstract: Nitrogen-doped graphene (N-graphene) is obtained by...

  16. Nitrogen-Doped Graphene and its Application in Electrochemical...

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

    Doped Graphene and its Application in Electrochemical Biosensing. Nitrogen-Doped Graphene and its Application in Electrochemical Biosensing. Abstract: Chemical doping with foreign...

  17. Infrared Spectroscopic Characterization of Lipid-Alkylsiloxane Hybrid Bilayer Membranes at Oxide

    E-Print Network [OSTI]

    Parikh, Atul N.

    Infrared Spectroscopic Characterization of Lipid-Alkylsiloxane Hybrid Bilayer Membranes at Oxide and Gm1/OTS/SiO2/Si, were characterized using a combined application of infrared spectroscopy, null

  18. Buckling analysis of singly curved shallow bi-layered arch under concentrated loading

    E-Print Network [OSTI]

    Sonawane, Mahesh

    2009-05-15T23:59:59.000Z

    viable alternative to conventional sandwich materials in applications where the functional requirements can be met without the second face sheet of the sandwich. For structural applications bi-layered materials are required to have oil canning...

  19. Chirality-Assisted Electronic Cloaking of Confined States in Bilayer Graphene

    E-Print Network [OSTI]

    Gu, Nan

    We show that the strong coupling of pseudospin orientation and charge carrier motion in bilayer graphene has a drastic effect on transport properties of ballistic p-n-p junctions. Electronic states with zero momentum ...

  20. Enhanced sensitivity of a microfabricated resonator using a graphene-polystyrene bilayer membrane

    SciTech Connect (OSTI)

    Yun, Minhyuk; Lee, Eunho; Cho, Kilwon; Jeon, Sangmin, E-mail: jeons@postech.ac.kr [Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang (Korea, Republic of)

    2014-08-18T23:59:59.000Z

    A graphene layer was synthesized using chemical vapor deposition methods and a polystyrene solution was spin-cast onto the graphene film. The graphene-polystyrene bilayer membrane was attached between the two tines of a microfabricated quartz tuning fork (QTF). The modulus of the graphene-polystyrene bilayer was measured to be twice that of a pristine polystyrene membrane. Exposure of the membrane-coated QTF to ethanol vapor decreased the resonance frequency of the microresonator. The bilayer membrane-coated QTF produced a frequency change that was three times the change obtained using a polystyrene membrane-coated QTF, with a lower degree of degradation in the Q factor. The limit of detection of the bilayer membrane-coated QTF to ethanol vapor was determined to be 20?ppm.

  1. Unraveling the interlayer-related phonon self-energy renormalization in bilayer graphene

    E-Print Network [OSTI]

    Araujo, Paulo Antonio Trinidade

    In this letter, we present a step towards understanding the bilayer graphene (2LG) interlayer (IL)-related phonon combination modes and overtones as well as their phonon self-energy renormalizations by using both gate-modulated ...

  2. Correlation effects in (111) bilayers of perovskite transition-metal oxides

    SciTech Connect (OSTI)

    Okamoto, Satoshi [ORNL] [ORNL; Zhu, Wenguang [University of Science and Technology of China] [University of Science and Technology of China; Nomura, Yusuke [University of Tokyo, Japan] [University of Tokyo, Japan; Arita, R. [University of Tokyo, Japan] [University of Tokyo, Japan; Xiao, Di [Carnegie Mellon University (CMU)] [Carnegie Mellon University (CMU); Nagaosa, Naoto [University of Tokyo, Japan] [University of Tokyo, Japan

    2014-01-01T23:59:59.000Z

    We investigate the correlation-induced Mott, magnetic, and topological phase transitions in artificial (111) bilayers of perovskite transition-metal oxides LaAuO3 and SrIrO3 for which the previous density-functional theory calculations predicted topological insulating states. Using the dynamical-mean-field theory with realistic band structures and Coulomb interactions, LaAuO3 bilayer is shown to be far away from a Mott insulating regime, and a topological-insulating state is robust. On the other hand, SrIrO3 bilayer is on the verge of an orbital-selective topological Mott transition and turns to a trivial insulator by an antiferromagnetic ordering. Oxide bilayers thus provide a novel class of topological materials for which the interplay between the spin-orbit coupling and electron-electron interactions is a fundamental ingredient.

  3. Intrinsic Electronic Transport Properties of High-Quality Monolayer and Bilayer MoS[subscript 2

    E-Print Network [OSTI]

    Baugher, Britton W. H.

    We report electronic transport measurements of devices based on monolayers and bilayers of the transition-metal dichalcogenide MoS[subscript 2]. Through a combination of in situ vacuum annealing and electrostatic gating ...

  4. Bilayer graphene growth by low pressure chemical vapor deposition on copper foil

    E-Print Network [OSTI]

    Fang, Wenjing, S.M. Massachusetts Institute of Technology

    2012-01-01T23:59:59.000Z

    Successfully integrating graphene in standard processes for applications in electronics relies on the synthesis of high-quality films. In this work we study Low Pressure Chemical Vapor Deposition (LPCVD) growth of bilayer ...

  5. Zone folding effect in Raman G-band intensity of twisted bilayer graphene

    E-Print Network [OSTI]

    Dresselhaus, Mildred

    The G-band Raman intensity is calculated for twisted bilayer graphene as a function of laser excitation energy based on the extended tight binding method. Here we explicitly consider the electron-photon and electron-phonon ...

  6. Debonding in bi-layer material systems under moisture effect : a multiscale approach

    E-Print Network [OSTI]

    Lau, Tak-bun, Denvid

    2012-01-01T23:59:59.000Z

    Bi-layer material systems are found in various engineering applications ranging from nano-scale components, such as thin films in circuit boards, to macro-scale structures such as adhesive bonding in aerospace and civil ...

  7. Europium-doped barium bromide iodide

    E-Print Network [OSTI]

    Gundiah, Gautam

    2010-01-01T23:59:59.000Z

    J. Simpson and M. Weil Europium-doped barium bromide iodideOnline ISSN 1600-5368 Europium-doped barium bromide iodide0.96 Eu 0.04 BrI (barium europium bromide iodide) were grown

  8. Mechanisms of budding of nanoscale particles through lipid bilayers

    E-Print Network [OSTI]

    Teresa Ruiz-Herrero; Enrique Velasco; Michael F. Hagan

    2012-02-21T23:59:59.000Z

    We examine the budding of a nanoscale particle through a lipid bilayer using molecular dynamics simulations, free energy calculations, and an elastic theory, with the aim of determining the extent to which equilibrium elasticity theory can describe the factors that control the mechanism and efficiency of budding. The particle is a smooth sphere which experiences attractive interactions to the lipid head groups. Depending on the parameters, we observe four classes of dynamical trajectories: particle adhesion to the membrane, stalled partially wrapped states, budding followed by scission, and membrane rupture. In most regions of parameter space we find that the elastic theory agrees nearly quantitatively with the simulated phase behavior as a function of adhesion strength, membrane bending rigidity, and particle radius. However, at parameter values near the transition between particle adhesion and budding, we observe long-lived partially wrapped states which are not captured by existing elastic theories. These states could constrain the accessible system parameters for those enveloped viruses or drug delivery vehicles which rely on exo- or endocytosis for membrane transport.

  9. Nanoporous microbead supported bilayers: stability, physical characterization, and incorporation of functional transmembrane proteins.

    SciTech Connect (OSTI)

    Davis, Ryan W. (University of New Mexico, Albuquerque, NM); Brozik, James A. (University of New Mexico, Albuquerque, NM); Brozik, Susan Marie; Cox, Jason M. (University of New Mexico, Albuquerque, NM); Lopez, Gabriel P. (University of New Mexico, Albuquerque, NM); Barrick, Todd A. (University of New Mexico, Albuquerque, NM); Flores, Adrean (University of New Mexico, Albuquerque, NM)

    2007-03-01T23:59:59.000Z

    The introduction of functional transmembrane proteins into supported bilayer-based biomimetic systems presents a significant challenge for biophysics. Among the various methods for producing supported bilayers, liposomal fusion offers a versatile method for the introduction of membrane proteins into supported bilayers on a variety of substrates. In this study, the properties of protein containing unilamellar phosphocholine lipid bilayers on nanoporous silica microspheres are investigated. The effects of the silica substrate, pore structure, and the substrate curvature on the stability of the membrane and the functionality of the membrane protein are determined. Supported bilayers on porous silica microspheres show a significant increase in surface area on surfaces with structures in excess of 10 nm as well as an overall decrease in stability resulting from increasing pore size and curvature. Comparison of the liposomal and detergent-mediated introduction of purified bacteriorhodopsin (bR) and the human type 3 serotonin receptor (5HT3R) are investigated focusing on the resulting protein function, diffusion, orientation, and incorporation efficiency. In both cases, functional proteins are observed; however, the reconstitution efficiency and orientation selectivity are significantly enhanced through detergent-mediated protein reconstitution. The results of these experiments provide a basis for bulk ionic and fluorescent dye-based compartmentalization assays as well as single-molecule optical and single-channel electrochemical interrogation of transmembrane proteins in a biomimetic platform.

  10. General model of phospholipid bilayers in fluid phase within the single chain mean field theory

    SciTech Connect (OSTI)

    Guo, Yachong; Baulin, Vladimir A. [Departament d’Enginyeria Química, Universitat Rovira i Virgili, Av. dels Paisos Catalans 26, 43007 Tarragona (Spain)] [Departament d’Enginyeria Química, Universitat Rovira i Virgili, Av. dels Paisos Catalans 26, 43007 Tarragona (Spain); Pogodin, Sergey [Institute of Chemical Research of Catalonia, ICIQ, Av. Paisos Catalans 16, 43007 Tarragona (Spain)] [Institute of Chemical Research of Catalonia, ICIQ, Av. Paisos Catalans 16, 43007 Tarragona (Spain)

    2014-05-07T23:59:59.000Z

    Coarse-grained model for saturated phospholipids: 1,2-didecanoyl-sn-glycero-3-phosphocholine (DCPC), 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC), 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and unsaturated phospholipids: 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), 1,2- dioleoyl-sn-glycero-3-phosphocholine (DOPC) is introduced within the single chain mean field theory. A single set of parameters adjusted for DMPC bilayers gives an adequate description of equilibrium and mechanical properties of a range of saturated lipid molecules that differ only in length of their hydrophobic tails and unsaturated (POPC, DOPC) phospholipids which have double bonds in the tails. A double bond is modeled with a fixed angle of 120°, while the rest of the parameters are kept the same as saturated lipids. The thickness of the bilayer and its hydrophobic core, the compressibility, and the equilibrium area per lipid correspond to experimentally measured values for each lipid, changing linearly with the length of the tail. The model for unsaturated phospholipids also fetches main thermodynamical properties of the bilayers. This model is used for an accurate estimation of the free energies of the compressed or stretched bilayers in stacks or multilayers and gives reasonable estimates for free energies. The proposed model may further be used for studies of mixtures of lipids, small molecule inclusions, interactions of bilayers with embedded proteins.

  11. Method of doping a semiconductor

    DOE Patents [OSTI]

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

    1983-01-01T23:59:59.000Z

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

  12. PHYSICAL REVIEW B 83, 193403 (2011) First-principles study of strain-induced modulation of energy gaps of graphene/BN and BN bilayers

    E-Print Network [OSTI]

    Pandey, Ravi

    2011-01-01T23:59:59.000Z

    gaps of graphene/BN and BN bilayers Xiaoliang Zhong, Yoke Khin Yap, and Ravindra Pandey* Department May 2011) First-principles calculations based on density functional theory are performed on graphene/BN and BN bilayers to investigate the effect of the strain on their energy gaps. For the graphene/BN bilayer

  13. Comparing Simulations of Lipid Bilayers to Scattering Data: The GROMOS 43A1-S3 Force Field

    E-Print Network [OSTI]

    Nagle, John F.

    , and excellent, fit to neutron scattering data occurs at an interpolated AN = 66.6 Å2 and the best lipid bilayers. It was not, however, compared to neutron scattering data which has become particularlyComparing Simulations of Lipid Bilayers to Scattering Data: The GROMOS 43A1-S3 Force Field Anthony

  14. Magnetization rotation in a superconductor/ferromagnet bilayer ring structure Diana G. Gheorghe and Rinke J. Wijngaarden

    E-Print Network [OSTI]

    Wijngaarden, Rinke J.

    Magnetization rotation in a superconductor/ferromagnet bilayer ring structure Diana G. Gheorghe and Superconducting Materials Group, Kamerlingh Onnes Laboratory, University Leiden, P.O. Box 9504, 2300 RA Leiden The magnetic-flux distribution in a bilayer ring consisting of superconducting Nb and ferromagnetic amor- phous

  15. Anisotropic Motion and Molecular Dynamics of Cholesterol, Lanosterol, and Ergosterol in Lecithin Bilayers Studied by Quasi-elastic Neutron Scattering

    E-Print Network [OSTI]

    Brown, Michael F.

    Bilayers Studied by Quasi-elastic Neutron Scattering Emil Endress, Helmut Heller,§ He´le`ne CasaltaVised Manuscript ReceiVed June 27, 2002 ABSTRACT: Quasi-elastic neutron scattering (QENS) was employed to study of motion within the bilayer on the molecular dynamics time scale. In a recent quasi-elastic neutron

  16. Effects of Sugars on Lipid Bilayers during Dehydration ? SAXS/WAXS Measurements and Quantitative Model

    SciTech Connect (OSTI)

    Lenne, Thomas; Garvey, Christopher J.; Koster, Karen L.; Bryant, Gary; (ANSTO); (USD); (RMIT)

    2009-04-02T23:59:59.000Z

    We present an X-ray scattering study of the effects of dehydration on the bilayer and chain-chain repeat spacings of dipalmitoylphosphatidylcholine bilayers in the presence of sugars. The presence of sugars has no effect on the average spacing between the phospholipid chains in either the fluid or gel phase. Using this finding, we establish that for low sugar concentrations only a small amount of sugar exclusion occurs. Under these conditions, the effects of sugars on the membrane transition temperatures can be explained quantitatively by the reduction in hydration repulsion between bilayers due to the presence of the sugars. Specific bonding of sugars to lipid headgroups is not required to explain this effect.

  17. Air-stable droplet interface bilayers on oil-infused surfaces

    SciTech Connect (OSTI)

    Boreyko, Jonathan B [ORNL] [ORNL; Polizos, Georgios [Oak Ridge National Laboratory (ORNL)] [Oak Ridge National Laboratory (ORNL); Datskos, Panos G [ORNL] [ORNL; Sarles, Stephen A [ORNL] [ORNL; Collier, Pat [ORNL] [ORNL

    2014-01-01T23:59:59.000Z

    Droplet interface bilayers (DIBs) are versatile model membranes useful for synthetic biology and biosensing; however, to date they have always been confined to fluid reservoirs. Here, we demonstrate that when two or more water droplets collide on an oil-infused substrate, they exhibit non-coalescence due to the formation of a thin oil film that gets squeezed between the droplets from the bottom-up. We show that when phospholipids are included in the water droplets, a stable droplet interface bilayer forms between the non-coalescing water droplets. As with traditional oil-submerged DIBs, we were able to characterize ion channel transport by incorporating peptides into each droplet. Our findings reveal that droplet interface bilayers can function in air environments, which could potentially enable biosensing of atmospheric particulates.

  18. Transfer matrix theory of monolayer graphene/bilayer graphene heterostructure superlattice

    SciTech Connect (OSTI)

    Wang, Yu, E-mail: ywang@semi.ac.cn [Department of Physics, Faculty of Science, Kunming University of Science and Technology, Kunming 650500 (China)

    2014-10-28T23:59:59.000Z

    We have formulated a transfer matrix method to investigate electronic properties of graphene heterostructure consisting of monolayer graphene and bilayer counterpart. By evaluating transmission, conductance, and band dispersion, we show that, irrespective of the different carrier chiralities in monolayer graphene and bilayer graphene, superlattice consisting of biased bilayer graphene barrier and monolayer graphene well can mimic the electronic properties of conventional semiconductor superlattice, displaying the extended subbands in the quantum tunneling regime and producing anisotropic minigaps for the classically allowed transport. Due to the lateral confinement, the lowest mode has shifted away from the charge neutral point of monolayer graphene component, opening a sizeable gap in concerned structure. Following the gate-field and geometry modulation, all electronic states and gaps between them can be externally engineered in an electric-controllable strategy.

  19. Perturbative analysis of the conductivity in disordered monolayer and bilayer graphene

    E-Print Network [OSTI]

    Andreas Sinner; Klaus Ziegler

    2011-12-02T23:59:59.000Z

    The DC conductivity of monolayer and bilayer graphene is studied perturbatively for different types of disorder. In the case of monolayer, an exact cancellation of logarithmic divergences occurs for all disorder types. The total conductivity correction for a random vector potential is zero, while for a random scalar potential and a random gap it acquires finite corrections. We identify the diagrams which are responsible for these corrections and extrapolate the finite contributions to higher orders which gives us general expressions for the conductivity of weakly disordered monolayer graphene. In the case of bilayer graphene, a cancellation of all contributions for all types of disorder takes place. Thus, the minimal conductivity of bilayer graphene turns out to be very robust against disorder.

  20. Size dependence, stability, and a transition to buckling in model reverse bilayers

    E-Print Network [OSTI]

    J. Stecki

    2006-07-03T23:59:59.000Z

    Molecular Dynamics simulations of a model bilayer made of surfactant dimers in a Lennard-Jones solvent are reported for three sizes of the systems up to an area of $100\\sigma \\times 100\\sigma$ and for a large interval of specific areas:from hole formation under tension to the floppy state of a compressed bilayer. The transition to the floppy state appears quite abrupt and discontinuous; in the floppy state the lateral tension is negative. Lateral tension and the structure factor were determined for all 3 sizes and all areas; the apparent rigidity constant and apparent surface tension are determined and correlated with the specific area and the finite size. The replacement of the $1/q^2$ capillary-wave divergence by a pole is accounted for and explained. The derivative of the lateral tension jumps from a high value in a flat bilayer to a low value in the floppy, rough, and buckling state, where the tension itself is negative.

  1. Method of doping organic semiconductors

    DOE Patents [OSTI]

    Kloc, Christian Leo (Constance, DE); Ramirez, Arthur Penn (Summit, NJ); So, Woo-Young (New Providence, NJ)

    2012-02-28T23:59:59.000Z

    A method includes the steps of forming a contiguous semiconducting region and heating the region. The semiconducting region includes polyaromatic molecules. The heating raises the semiconducting region to a temperature above room temperature. The heating is performed in the presence of a dopant gas and the absence of light to form a doped organic semiconducting region.

  2. Direct measurement of DNA-mediated adhesion between lipid bilayers

    E-Print Network [OSTI]

    S. F. Shimobayashi; B. M. Mognetti; L. Parolini; D. Orsi; P. Cicuta; L. Di Michele

    2015-04-16T23:59:59.000Z

    Multivalent interactions between deformable mesoscopic units are ubiquitous in biology, where membrane macromolecules mediate the interactions between neighbouring living cells and between cells and solid substrates. Lately, analogous artificial materials have been synthesised by functionalising the outer surface of compliant Brownian units, for example emulsion droplets and lipid vesicles, with selective linkers, in particular short DNA sequences. This development extended the range of applicability of DNA as a selective glue, originally applied to solid nano and colloidal particles. On very deformable lipid vesicles, the coupling between statistical effects of multivalent interactions and mechanical deformation of the membranes gives rise to complex emergent behaviours, as we recently contributed to demonstrate [Parolini et al., Nature Communications, 2015, 6, 5948]. Several aspects of the complex phenomenology observed in these systems still lack a quantitative experimental characterisation and fundamental understanding. Here we focus on the DNA-mediated multivalent interactions of a single liposome adhering to a flat supported bilayer. This simplified geometry enables the estimate of the membrane tension induced by the DNA-mediated adhesive forces acting on the liposome. Our experimental investigation is completed by morphological measurements and the characterisation of the DNA-melting transition, probed by in-situ F\\"{o}rster Resonant Energy Transfer spectroscopy. Experimental results are compared with the predictions of an analytical theory that couples the deformation of the vesicle to a full description of the statistical mechanics of mobile linkers. With at most one fitting parameter, our theory is capable of semi-quantitatively matching experimental data, confirming the quality of the underlying assumptions.

  3. Mixed lipid bilayers with locally varying spontaneous curvature and bending

    E-Print Network [OSTI]

    Guillaume Gueguen; Nicolas Destainville; Manoel Manghi

    2014-08-27T23:59:59.000Z

    A model of lipid bilayers made of a mixture of two lipids with different average compositions on both leaflets, is developed. A Landau hamiltonian describing the lipid-lipid interactions on each leaflet, with two lipidic fields $\\psi_1$ and $\\psi_2$, is coupled to a Helfrich one, accounting for the membrane elasticity, via both a local spontaneous curvature, which varies as $C_0+C_1(\\psi_1-\\psi_2)/2$, and a bending modulus equal to $\\kappa_0+\\kappa_1(\\psi_1+\\psi_2)/2$. This model allows us to define curved patches as membrane domains where the asymmetry in composition, $\\psi_1-\\psi_2$, is large, and thick and stiff patches where $\\psi_1+\\psi_2$ is large. These thick patches are good candidates for being lipidic rafts, as observed in cell membranes, which are composed primarily of saturated lipids forming a liquid-ordered domain and are known to be thick and flat nano-domains. The lipid-lipid structure factors and correlation functions are computed for globally spherical membranes and planar ones. Phase diagrams are established, within a Gaussian approximation, showing the occurrence of two types of Structure Disordered phases, with correlations between either curved or thick patches, and an Ordered phase, corresponding to the divergence of the structure factor at a finite wave vector. The varying bending modulus plays a central role for curved membranes, where the driving force $\\kappa_1C_0^2$ is balanced by the line tension, to form raft domains of size ranging from 10 to 100~nm. For planar membranes, raft domains emerge via the cross-correlation with curved domains. A global picture emerges from curvature-induced mechanisms, described in the literature for planar membranes, to coupled curvature- and bending-induced mechanisms in curved membranes forming a closed vesicle.

  4. Vapor deposition of water on graphitic surfaces: Formation of amorphous ice, bilayer ice, ice I, and liquid water

    SciTech Connect (OSTI)

    Lupi, Laura; Kastelowitz, Noah; Molinero, Valeria, E-mail: Valeria.Molinero@utah.edu [Department of Chemistry, The University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112-0850 (United States)

    2014-11-14T23:59:59.000Z

    Carbonaceous surfaces are a major source of atmospheric particles and could play an important role in the formation of ice. Here we investigate through molecular simulations the stability, metastability, and molecular pathways of deposition of amorphous ice, bilayer ice, and ice I from water vapor on graphitic and atomless Lennard-Jones surfaces as a function of temperature. We find that bilayer ice is the most stable ice polymorph for small cluster sizes, nevertheless it can grow metastable well above its region of thermodynamic stability. In agreement with experiments, the simulations predict that on increasing temperature the outcome of water deposition is amorphous ice, bilayer ice, ice I, and liquid water. The deposition nucleation of bilayer ice and ice I is preceded by the formation of small liquid clusters, which have two wetting states: bilayer pancake-like (wetting) at small cluster size and droplet-like (non-wetting) at larger cluster size. The wetting state of liquid clusters determines which ice polymorph is nucleated: bilayer ice nucleates from wetting bilayer liquid clusters and ice I from non-wetting liquid clusters. The maximum temperature for nucleation of bilayer ice on flat surfaces, T{sub B}{sup max} is given by the maximum temperature for which liquid water clusters reach the equilibrium melting line of bilayer ice as wetting bilayer clusters. Increasing water-surface attraction stabilizes the pancake-like wetting state of liquid clusters leading to larger T{sub B}{sup max} for the flat non-hydrogen bonding surfaces of this study. The findings of this study should be of relevance for the understanding of ice formation by deposition mode on carbonaceous atmospheric particles, including soot.

  5. Investigation of the effect of bilayer membrane structures and fluctuation amplitudes on SANS/SAXS profile for short membrane wavelength

    SciTech Connect (OSTI)

    Lee, Victor; Hawa, Takumi [School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, Oklahoma 73019 (United States)] [School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, Oklahoma 73019 (United States)

    2013-09-28T23:59:59.000Z

    The effect of bilayer membrane structures and fluctuation amplitudes on small angle neutron scattering (SANS) and small angle X-ray scattering (SAXS) profile is investigated based on harmonic motions of the surfactant bilayers with bending as well as thickness fluctuation motions. In this study we consider the case in which the wavelength of the bilayer membrane is shorter than the thickness of the membrane. We find that the thickness of the surfactant bilayer membrane, d{sub m}, affects both q{sub dip} and q{sub peak} of I(q,0) profile, and that the fluctuation amplitude, a, of the membrane changes the peak of I(q,0). A simple formula is derived to estimate the thickness of the bilayer based on the q{sub dip} of the profile obtained from the simulation. The resulting estimates of the thickness of the bilayer with harmonic motion showed accuracy within 1%. Moreover, the bilayer thicknesses estimated from the proposed formula show an excellent agreement with the SANS and SAXS experimental results available in the literatures. We also propose a curve fit model, which describes the relationship between the fluctuation amplitude and the normalized q{sub peak} ratio. The present results show the feasibility of the simple formula to estimate the fluctuation amplitude based on the SANS and SAXS profiles.

  6. Hollow structures with bilayer graphene walls Peter J.F. Harris *

    E-Print Network [OSTI]

    Harris, Peter J F

    Hollow structures with bilayer graphene walls Peter J.F. Harris * Centre for Advanced Microscopy, J-discharge [7,8]. This new carbon apparently consists of hollow graphitic shells bounded by curved and faceted with nano-scale carbon particles, or short nanotubes; in some cases, nanotubes are found to be seamlessly

  7. Intercalation of a Nonionic Surfactant (C10E3) bilayer into a Na-Montmorillonite Clay

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Intercalation of a Nonionic Surfactant (C10E3) bilayer into a Na-Montmorillonite Clay Régis of a Na-montmorillonite clay at several concentrations. The synthesized organoclays were characterized surfactants in clays where the expansion of the interlayer space was limited to two monolayers parallel

  8. Dependence of exchange coupling interaction on micromagnetic constants in hard/soft magnetic bilayer systems

    E-Print Network [OSTI]

    Rubloff, Gary W.

    Dependence of exchange coupling interaction on micromagnetic constants in hard/soft magnetic bilayer systems A. J. Zambano,1, * H. Oguchi,1 I. Takeuchi,1 Y. Choi,2,3 J. S. Jiang,2 J. P. Liu,3 S. E December 2006; published 30 April 2007 To elucidate the dependence of exchange coupling behavior of hard/soft

  9. Magnetization reversal and exchange bias effects in hard/soft ferromagnetic bilayers with orthogonal anisotropies

    E-Print Network [OSTI]

    Ross, Caroline A.

    The magnetization reversal processes are discussed for exchange-coupled ferromagnetic hard/soft bilayers made from Co[subscript 0.66]Cr[subscript 0.22]Pt[subscript 0.12] (10 and 20 nm)/Ni (from 0 to 40 nm) films with ...

  10. SUPPLEMENTARY MATERIAL Lipid bilayer structure determined by the simultaneous analysis of neutron

    E-Print Network [OSTI]

    Nagle, John F.

    scattering intensities I(q) for both neutrons and x-rays using )()()()( qPqPqIqF TSLC= , (1.) where PLC in structure between oriented and spherical bilayers experimentally using both neutron and x-ray scattering in (2). Our study concluded no difference between the two for x-ray and neutron scattering data

  11. Bilayer/cytoskeleton interactions in lipid-symmetric erythrocytes assessed by a photoactivable phospholipid analogue

    SciTech Connect (OSTI)

    Pradhan, D.; Schlegel, R.A. (Pennsylvania State Univ., University Park (United States)); Williamson, P. (Amherst Coll., MA (United States))

    1991-08-06T23:59:59.000Z

    Two mechanisms have been proposed for maintenance of transbilayer phospholipid asymmetry in the erythrocyte plasma membrane, one involving specific interactions between the aminophospholipids of the inner leaflet of the bilayer and the cytoskeleton, particularly spectrin, and the other involving the aminophospholipid translocase. If the former mechanism is correct, then erythrocytes which have lost their asymmetric distribution of phospholipids should display altered bilayer/cytoskeleton interactions. To test this possibility, normal erythrocytes, erythrocytes from patients with chronic myelogenous leukemia or sickle disease, and lipid-symmetric and -asymmetric erythrocyte ghosts were labeled with the radioactive photoactivable analogue of phosphatidylethanolamine, 2-(2-azido-4-nitrobenzoyl)-1-acyl-sn-glycero-3-phospho({sup 14}C) ethanolamine (({sup 14}C)AzPE), previously shown to label cytoskeletal proteins from the bilayer. The labeling pattern of cytoskeletal proteins in pathologic erythrocytes and lipid-asymmetric erythrocyte ghosts was indistinguishable from normal erythrocytes, indicating that the probe detects no differences in bilayer/cytoskeleton interactions in these cells. In contrast, in lipid-symmetric erythrocyte ghosts, labeling of bands 4.1 and 4.2 and actin, and to a lesser extent ankyrin, by ({sup 14}C)AzPE was considerably reduced. Significantly, however, labeling of spectrin was unaltered in the lipid-symmetric cells. These results do not support a model in which spectrin is involved in the maintenance of an asymmetric distribution of phospholipids in erythrocytes.

  12. Raman spectra of out-of-plane phonons in bilayer graphene

    E-Print Network [OSTI]

    Sato, Kentaro

    The double resonance Raman spectra of the overtone of the out-of-plane tangential optical (oTO) phonon and of combinations of the LO, ZO, and ZA phonons with one another are calculated for bilayer graphene. In the case of ...

  13. NEUTRON SCATTERING SHOWS THAT CYTOCHROME b5 PENETRATES DEEPLY INTO THE LIPID BILAYER

    E-Print Network [OSTI]

    NEUTRON SCATTERING SHOWS THAT CYTOCHROME b5 PENETRATES DEEPLY INTO THE LIPID BILAYER E. P. GOGOL to lipid vesicles using neutron small-angle scattering methods. To increase scat- tering contrast between of a highly deuterated phospholipid. Small-angle neutron diffraction patterns were collected in a series of H

  14. Dynamic rupture of polymermetal bilayer plates G.J. McShane a

    E-Print Network [OSTI]

    Fleck, Norman A.

    : Bilayers Necking Petalling Underwater blast a b s t r a c t Recent theoretical assessments of metal capacity while the PU1 coating provides no such synergistic effect. The dynamic bulge forming tests blast impulse. Given the ease of apply- ing polyurethane coatings they may provide a practical solution

  15. Growth of Single- and Bilayer ZnO on Au(111) and Interaction with Copper

    SciTech Connect (OSTI)

    Deng, Xingyi; Yao, Kun; Sun, Keju; Li, Wei-Xue; Lee, Junseok; Matranga, Christopher

    2013-05-30T23:59:59.000Z

    The stoichiometric single- and bi-layer ZnO(0001) have been prepared by reactive deposition of Zn on Au(111) and studied in detail with X-ray photoelectron spectroscopy, scanning tunneling microscopy, and density functional theory calculations. Both single- and bi-layer ZnO(0001) adopt a planar, graphite-like structure similar to freestanding ZnO(0001) due to the weak van der Waals interactions dominating their adhesion with the Au(111) substrate. At higher temperature, the single-layer ZnO(0001) converts gradually to bi-layer ZnO(0001) due to the twice stronger interaction between two ZnO layers than the interfacial adhesion of ZnO with Au substrate. It is found that Cu atoms on the surface of bi-layer ZnO(0001) are mobile with a diffusion barrier of 0.31 eV, and likely to agglomerate and form nanosized particles at low coverages; while Cu atoms tend to penetrate a single layer of ZnO(0001) with a barrier of 0.10 eV, resulting in a Cu free surface.

  16. Acid Doped Membranes for High Temperature PEMFC

    Broader source: Energy.gov [DOE]

    Presentation on Acid Doped Membranes for High Temperature PEMFC to the High Temperature Membrane Working Group, May 25, 2004 in Philadelphia, PA.

  17. Lanthanide doped barium phosphorous oxide scintillators

    DOE Patents [OSTI]

    Borade, Ramesh B; Bourret-Courchesne, Edith; Denzo, Stephen E

    2013-02-26T23:59:59.000Z

    The present invention provides for a composition comprising an inorganic scintillator comprising a lanthanide-doped barium phosphorous oxide useful for detecting nuclear material.

  18. Lanthanide doped strontium barium mixed halide scintillators

    SciTech Connect (OSTI)

    Gundiah, Gautam; Bizarri, Gregory; Hanrahan, Stephen M; Bourret-Courchesne, Edith; Derenzo, Stephen E

    2013-07-16T23:59:59.000Z

    The present invention provides for a composition comprising an inorganic scintillator comprising a lanthanide-doped strontium barium mixed halide useful for detecting nuclear material.

  19. Observation of green emission from Ce3+ doped gadolinium oxide...

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

    green emission from Ce3+ doped gadolinium oxide nanoparticles. Observation of green emission from Ce3+ doped gadolinium oxide nanoparticles. Abstract: Green emission at around 500...

  20. Effect of Mn doping on the structural, morphological, optical...

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

    Mn doping on the structural, morphological, optical and magnetic properties of indium tin oxide films. Effect of Mn doping on the structural, morphological, optical and magnetic...

  1. Watermelon-like iron nanoparticles: Cr doping effect on magnetism...

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

    Watermelon-like iron nanoparticles: Cr doping effect on magnetism and magnetization interaction reversal. Watermelon-like iron nanoparticles: Cr doping effect on magnetism and...

  2. Mass-related inversion symmetry breaking and phonon self-energy renormalization in isotopically labeled AB-stacked bilayer graphene

    E-Print Network [OSTI]

    Araujo, Paulo Antonio Trinidade

    A mass-related symmetry breaking in isotopically labeled bilayer graphene (2LG) was investigated during in-situ electrochemical charging of AB stacked (AB-2LG) and turbostratic (t-2LG) layers. The overlap of the two ...

  3. Indirect heating of Pt by non-equilibrium electrons in Au in a nanoscale Pt/Au bilayer

    E-Print Network [OSTI]

    Cahill, David G.

    -line equivalent-circuit. For optical exciation of either the Pt or Au side of the bilayer, the majority of energy excitations which are then driven out of thermal equilibrium with the vibrations of the atomic lattice.1

  4. Direct and quantitative broadband absorptance spectroscopy on small objects using Fourier transform infrared spectrometer and bilayer cantilever probes

    E-Print Network [OSTI]

    Hsu, Wei-Chun

    A measurement platform is introduced that combines a bilayer cantilever probe with a Fourier transform infrared spectrometer to measure absolute spectral absorptance between wavelengths of 3??m and 18??m directly and ...

  5. Tuning of the spin pumping in yttrium iron garnet/Au bilayer system by fast thermal treatment

    SciTech Connect (OSTI)

    Jin, Lichuan, E-mail: lichuanj@udel.edu, E-mail: hwzhang@uestc.edu.cn; Zhang, Huaiwu, E-mail: lichuanj@udel.edu, E-mail: hwzhang@uestc.edu.cn; Yang, Qinghui; Tang, Xiaoli; Zhong, Zhiyong [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology, Chengdu 610054 (China); Zhang, Dainan [Department of Electrical and Computer Engineering, University of Delaware, Newark, Delaware 19716 (United States); Xiao, John Q. [Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States)

    2014-05-07T23:59:59.000Z

    In this Letter, we investigated the influence of the fast thermal treatment on the spin pumping in ferromagnetic insulator yttrium iron garnet (YIG)/normal metal Au bilayer system. The YIG/Au bilayer thin films were treated by fast annealing process with different temperatures from 0 to 800?°C. The spin pumping was studied using ferromagnetic resonance. The surface evolution was investigated using a high resolution scanning microscopy and an atomic force microscopy. A strong thermal related spin pumping in YIG/Au bilayer system has been revealed. It was found that the spin pumping process can be enhanced by using fast thermal treatment due to the thermal modifications of the Au surface. The effective spin-mixing conductance of the fast thermal treated YIG/Au bilayer has been obtained.

  6. Potential commercial application of a bi-layer bone-ligament regeneration scaffold to anterior cruciate ligament replacement

    E-Print Network [OSTI]

    Li, Jessica C. (Jessica Ching-Yi)

    2006-01-01T23:59:59.000Z

    A business model was created in order to explore the commercial application of a bi-layer bone-ligament scaffold to the treatment of torn anterior cruciate ligaments (ACL) requiring replacement. The two main keys in producing ...

  7. Electron dynamics of the buffer layer and bilayer graphene on SiC

    SciTech Connect (OSTI)

    Shearer, Alex J.; Caplins, Benjamin W.; Suich, David E.; Harris, Charles B., E-mail: cbharris@berkeley.edu [Department of Chemistry, University of California at Berkeley, Berkeley, California 94720 (United States); Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Johns, James E. [Department of Chemistry, University of Minnesota Twin Cities, Minneapolis, Minnesota 55455 (United States); Hersam, Mark C. [Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Department of Chemistry, Northwestern University, Evanston, Illinois 60208 (United States)

    2014-06-09T23:59:59.000Z

    Angle- and time-resolved two-photon photoemission (TPPE) was used to investigate electronic states in the buffer layer of 4H-SiC(0001). An image potential state (IPS) series was observed on this strongly surface-bound buffer layer, and dispersion measurements indicated free-electron-like behavior for all states in this series. These results were compared with TPPE taken on bilayer graphene, which also show the existence of a free-electron-like IPS series. Lifetimes for the n?=?2, and n?=?3 states were obtained from time-resolved TPPE; slightly increased lifetimes were observed in the bilayer graphene sample for the n?=?2 the n?=?3 states. Despite the large band gap of graphene at the center of the Brillouin zone, the lifetime results demonstrate that the graphene layers do not behave as a simple tunneling barrier, suggesting that the buffer layer and graphene overlayers play a direct role in the decay of IPS electrons.

  8. Brillouin light scattering study of spin waves in NiFe/Co exchange spring bilayer films

    SciTech Connect (OSTI)

    Haldar, Arabinda; Banerjee, Chandrima; Laha, Pinaki; Barman, Anjan, E-mail: abarman@bose.res.in [Thematic Unit of Excellence on Nanodevice Technology, Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Kolkata 700098 (India)

    2014-04-07T23:59:59.000Z

    Spin waves are investigated in Permalloy(Ni{sub 80}Fe{sub 20})/Cobalt(Co) exchange spring bilayer thin films using Brillouin light scattering (BLS) experiment. The magnetic hysteresis loops measured by magneto-optical Kerr effect show a monotonic decrease in coercivity of the bilayer films with increasing Py thickness. BLS study shows two distinct modes, which are modelled as Damon-Eshbach and perpendicular standing wave modes. Linewidths of the frequency peaks are found to increase significantly with decreasing Py layer thickness. Interfacial roughness causes to fluctuate exchange coupling at the nanoscale regimes and the effect is stronger for thinner Py films. A quantitative analysis of the magnon linewidths shows the presence of strong local exchange coupling field which is much larger compared to macroscopic exchange field.

  9. Does water dope carbon nanotubes?

    SciTech Connect (OSTI)

    Bell, Robert A.; Payne, Michael C. [Theory of Condensed Matter Group, Cavendish Laboratory, Cambridge (United Kingdom); Mostofi, Arash A. [Department of Materials and Department of Physics, and the Thomas Young Centre for Theory and Simulation of Materials, Imperial College London, London SW7 2AZ (United Kingdom)

    2014-10-28T23:59:59.000Z

    We calculate the long-range perturbation to the electronic charge density of carbon nanotubes (CNTs) as a result of the physisorption of a water molecule. We find that the dominant effect is a charge redistribution in the CNT due to polarisation caused by the dipole moment of the water molecule. The charge redistribution is found to occur over a length-scale greater than 30 Å, highlighting the need for large-scale simulations. By comparing our fully first-principles calculations to ones in which the perturbation due to a water molecule is treated using a classical electrostatic model, we estimate that the charge transfer between CNT and water is negligible (no more than 10{sup ?4}?e per water molecule). We therefore conclude that water does not significantly dope CNTs, a conclusion that is consistent with the poor alignment of the relevant energy levels of the water molecule and CNT. Previous calculations that suggest water n-dopes CNTs are likely due to the misinterpretation of Mulliken charge partitioning in small supercells.

  10. X-ray small-angle scattering from sputtered CeO{sub 2}/C bilayers

    SciTech Connect (OSTI)

    Haviar, S.; Dubau, M.; Khalakhan, I.; Vorokhta, M.; Matolinova, I.; Matolin, V. [Department of Surface and Plasma Science, Faculty of Mathematics and Physics Charles University, V Holesovickach 2, 180 00, Prague 8 (Czech Republic); Vales, V.; Endres, J.; Holy, V. [Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2 (Czech Republic); Buljan, M. [Institute Ruder Boskovic, Bijenicka 54, 10000 Zagreb (Croatia); Bernstorff, S. [Sincrotrone ELETTRA, 34149 Basovizza, Trieste (Italy)

    2013-01-14T23:59:59.000Z

    Surface and interface morphology of cerium oxide/carbon bilayers used as thin-film catalysts is studied by grazing-incidence small-angle x-ray scattering, scanning electron microscopy, and atomic-force microscopy, and the dependence of the structural parameters on the thicknesses of the constituting layers is investigated. The applicability of x-ray scattering and its advantages over standard analytical methods are discussed.

  11. Quantum Hall Effect In Bilayer Systems And The Noncommutative Plane: A Toy Model Approach

    E-Print Network [OSTI]

    B. Basu; Subir Ghosh

    2005-07-19T23:59:59.000Z

    We have presented a quantum mechanical toy model for the study of Coulomb interactions in Quantum Hall (QH) system. Inclusion of Coulomb interaction is essential for the study of {\\it{bilayer}} QH system and our model can simulate it, in the compound state, in a perturbative framework. We also show that in the noncommutative plane, the Coulomb interaction is modified at a higher order in the noncommutativity parameter $\\theta$, and only if $\\theta$ varies from layer to layer in the QH system.

  12. Effects of truncating van der Waals interactions in lipid bilayer simulations

    SciTech Connect (OSTI)

    Huang, Kun, E-mail: huangk4@rpi.edu [Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); García, Angel E., E-mail: angel@rpi.edu [Department of Physics, Applied Physics and Astronomy, and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

    2014-09-14T23:59:59.000Z

    In membrane simulations, it is known that truncating electrostatic interactions results in artificial ordering of lipids at the truncation distance. However, less attention has been paid to the effect of truncating van der Waals (VDW) interactions. Since the VDW potential decays as r{sup ?6}, it is frequently neglected beyond a cutoff of around 1?nm. In some cases, analytical dispersion corrections appropriate for isotropic systems are applied to the pressure and the potential energy. In this work, we systematically study the effect of truncating VDW interactions at different cutoffs in 1,2-Dipalmitoyl-sn-glycero-3-phosphocholine bilayers with the Berger force field. We show that the area per lipid decreases systematically when the VDW cutoff (r{sub c}) increases. This dependence persists even when dispersion corrections are applied. Since the analytical form of the dispersion correction is only appropriate for isotropic systems, we suggest that a long VDW cutoff should be used in preference over a short VDW cutoff. To determine the appropriate cutoff, we simulate liquid pentadecane with the Berger parameters and find that r{sub c} ? 1.4 nm is sufficient to reproduce the density and the heat of vaporization of pentadecane. Bilayers simulated with r{sub c} ? 1.4 nm show an improved agreement with experiments in both the form factors and the deuterium order parameters. Finally, we report that the VDW cutoff has a significant impact on the lipid flip-flop energetics and an inappropriate short VDW cutoff results in a bilayer that is prone to form water defects across the bilayer.

  13. Microwave-induced spin currents in ferromagnetic-insulator|normal-metal bilayer system

    SciTech Connect (OSTI)

    Agrawal, Milan, E-mail: magrawal@physik.uni-kl.de [Fachbereich Physik and Landesforschungszentrum OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern (Germany); Graduate School Materials Science in Mainz, Gottlieb-Daimler-Strasse 47, 67663 Kaiserslautern (Germany); Serga, Alexander A.; Lauer, Viktor; Papaioannou, Evangelos Th.; Hillebrands, Burkard; Vasyuchka, Vitaliy I. [Fachbereich Physik and Landesforschungszentrum OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern (Germany)

    2014-09-01T23:59:59.000Z

    A microwave technique is employed to simultaneously examine the spin pumping and the spin Seebeck effect processes in a YIG|Pt bilayer system. The experimental results show that for these two processes, the spin current flows in opposite directions. The temporal dynamics of the longitudinal spin Seebeck effect exhibits that the effect depends on the diffusion of bulk thermal-magnons in the thermal gradient in the ferromagnetic-insulator|normal-metal system.

  14. Dynamic Recompartmentalization of Supported Lipid Bilayers Using Focused Femtosecond Laser Pulses

    E-Print Network [OSTI]

    Parikh, Atul N.

    repetition rate of 2.7 kHz at 3 nJ pulse energy for 100 ms produces a dark blurry spot (2 µm fwhm of these applications depend on high peak intensities (>1013 W/cm2) achieved within the focal volume under low-energy Information). The bilayer was maintained wet by sandwiching the sample with a DI water-filled hanging drop

  15. Phase diagram of the CF{sub 4} monolayer and bilayer on graphite

    SciTech Connect (OSTI)

    Thomas, Petros; Hess, George B., E-mail: gbh@virginia.edu [Physics Department, University of Virginia, Charlottesville, Virginia 22904 (United States)

    2014-05-21T23:59:59.000Z

    We report an experimental study of physisorbed monolayers and bilayers of CF{sub 4} on graphite using infrared reflection absorption spectroscopy supplemented by ellipsometry. The symmetric C–F stretch mode ?{sub 3} near 1283 cm{sup ?1} in the gas is strongly blue shifted in the film by dynamic dipole coupling. This blue shift provides a very sensitive measure of the inter-molecular spacing in the monolayer and, less directly, in the bilayer. We find that important corrections are necessary to the volumetric coverage scales used in previous heat capacity and x-ray diffraction studies of this system. This requires quantitative and some qualitative changes to the previously proposed phase diagram. We find evidence for a new phase transition in the middle of the hexagonal incommensurate region and construct new phase diagrams in both the variables coverage-temperature and chemical potential-temperature. We determine the compressibility and thermal expansion in the low-pressure hexagonal incommensurate phase and values for the entropy change in several phase transitions. Below about 55 K there is evidence of solution of up to 7% of an impurity, most likely CO, in our monolayer but not the bilayer film.

  16. Confinement-deconfinement transition due to spontaneous symmetry breaking in quantum Hall bilayers

    E-Print Network [OSTI]

    Pikulin, D I; Hyart, T

    2015-01-01T23:59:59.000Z

    Band-inverted electron-hole bilayers support quantum spin Hall insulator and exciton condensate phases [1-4]. We investigate such a bilayer in an external magnetic field. We show that the interlayer correlations lead to a formation of a helical quantum Hall exciton condensate state. In contrast to the chiral edge states of the quantum Hall exciton condensate in electron-electron bilayers [5-7], existence of the electron and hole counterpropagating edge modes result in formation of a ground state spin-texture not supporting gapless single-particle excitations. This feature has deep consequences for the low energy behavior of the system. Namely, the charged edge excitations in a sufficiently narrow Hall bar are confined i.e. a charge on one of the edges always gives rise to an opposite charge on the other edge. Moreover, we show that a magnetic field and gate voltages allow to control a confinement-deconfinement transition of charged edge excitations, which can be probed with nonlocal conductance. Confinement-d...

  17. Field Theoretic Study of Bilayer Membrane Fusion III: Membranes with Leaves of Different Composition

    E-Print Network [OSTI]

    Jae Youn Lee; Michael Schick

    2006-09-20T23:59:59.000Z

    We extend previous work on homogeneous bilayers to calculate the barriers to fusion of planar bilayers which contain two different amphiphiles, a lamellae-former and a hexagonal former, with different compositions of the twoin each leaf. Self-consistent field theory is employed, and both standard and alternative pathways are explored. We first calculate these barriers as the amount of hexagonal former is increased equally in both leaves to levels appropriate to the plasma membrane of human red blood cells. We follow these barriers as the composition of hexagonal-formers is then increased in the cis layer and decreased in the trans layer, again to an extent comparable to the biological system. We find that, while the fusion pathway exhibits two barriers in both the standard and alternative pathways, in both cases the magnitudes of these barriers are comparable to one another, and small, on the order of 13 kT. As a consequence, one expects that once the bilayers are brought sufficiently close to one another to initiate the process, fusion should occur rapidly.

  18. Interplay between intrinsic and stacking-fault magnetic domains in bi-layered manganites

    SciTech Connect (OSTI)

    Hossain, M.A; Burkhardt, Mark H.; Sarkar, S.; Ohldag, H.; Chuang, Y.-D.; Scholl, A.; Young, A.T.; Doran, A.; Dessau, D.S.; Zheng, H.; Mitchell, J.F.; Durr, H.A.; Stohr, J.

    2012-09-11T23:59:59.000Z

    We present a low temperature X-ray photoemission electron microscopy study of the bi-layered manganite compound La{sub 1.2}Sr{sub 1.8}Mn{sub 2}O{sub 7} (BL-LSMO) to investigate the influence of stacking faults, which are structurally and magnetically different from the bi-layered host. In BL-LSMO small magnetic moment persists to T* = 300K, well above the Curie temperature of 120K (T{sub C}). Our magnetic images show that 3D stacking faults are responsible for the T* transition. Furthermore, close to the T{sub C}, stacking faults are well coupled to the bi-layered host with latter magnetic domains controlling the spin direction of the stacking faults. Contrary to recent reports, we find that stacking faults do not seed magnetic domains in the host via an exchange spring mechanism and the intrinsic T{sub C} of the BL-LSMO is not lower than 120K.

  19. Controlled doping of graphene using ultraviolet irradiation

    SciTech Connect (OSTI)

    Luo Zhengtang [Department of Chemical and Biomolecular Engineering, Hong Kong University of Science and Technology, Clear Water Bay (Hong Kong); Pinto, Nicholas J.; Davila, Yarely [Department of Physics and Electronics, University of Puerto Rico at Humacao, Humacao, 00792 (Puerto Rico); Charlie Johnson, A. T. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396 (United States)

    2012-06-18T23:59:59.000Z

    The electronic properties of graphene are tunable via doping, making it attractive in low dimensional organic electronics. Common methods of doping graphene, however, adversely affect charge mobility and degrade device performance. We demonstrate a facile shadow mask technique of defining electrodes on graphene grown by chemical vapor deposition (CVD) thereby eliminating the use of detrimental chemicals needed in the corresponding lithographic process. Further, we report on the controlled, effective, and reversible doping of graphene via ultraviolet (UV) irradiation with minimal impact on charge mobility. The change in charge concentration saturates at {approx}2 Multiplication-Sign 10{sup 12} cm{sup -2} and the quantum yield is {approx}10{sup -5} e/photon upon initial UV exposure. This simple and controlled strategy opens the possibility of doping wafer-size CVD graphene for diverse applications.

  20. The physics doped Quantum Dimer Models

    E-Print Network [OSTI]

    Paris-Sud 11, Université de

    -charge separation ­ Topological defects and holon statistics · Approach based on the Quantum Dimer Model ­ A wide ­ Hole doping: exotic properties of holons #12;3 Collaborators · Arnaud Ralko (Toulouse) · Frédéric Mila superconductor under doping Holon (Q=e, S=0) « spin-charge separation » #12;8 Variational approach of RVB #12

  1. Effects of Synthetic Amphiphilic alpha-Helical Peptides on the Electrochemical and Structural Properties of Supported Hybrid Bilayers on Gold

    SciTech Connect (OSTI)

    Smith,M.; Tong, J.; Genzer, J.; Fischer, D.; Kilpatrick, P.

    2006-01-01T23:59:59.000Z

    Amphiphilic {alpha}-helices were formed from designed synthetic peptides comprising alanine, phenylalanine, and lysine residues. The insertion of the -helical peptides into hybrid bilayers assembled on gold was studied by a variety of methods to assess the resulting structural characteristics, such as electrical resistance and molecular orientation. Self-assembled monolayers (SAMs) of dodecanethiol (DDT); octadecanethiol (ODT); and 1,2-dipalmitoyl-sn-glycero-3-phosphothioethanol (DPPTE) were formed on gold substrates with and without incorporated peptide. Supported hybrid bilayers and multilayers of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) were formed on SAMs by the 'paint-freeze' method of bilayer formation. Modeling of electrochemical impedance spectroscopy data using equivalent electrochemical circuits revealed that the addition of peptide decreased dramatically the resistive element of the bilayer films while maintaining the value of the capacitive element, indicating successful incorporation of peptide into a well-formed bilayer. Near-edge X-ray absorption fine structure spectroscopy data provided evidence that the molecules in the SAMs and hybrid multilayers were ordered even in the presence of peptide. The peptide insertion into the SAM was confirmed by observing the {pi}* resonance peak correlating with phenylalanine and a peak in the nitrogen K-edge regime attributable to the peptide bond.

  2. Electrical Modulation of Ion Concentration in Dual-Gated Nanochannels Yang Liu, Qiushi Ran, and Robert W. Dutton

    E-Print Network [OSTI]

    Liu, Yang

    potential applications range from fuel cells [11] to desalination [12]. Nevertheless, in contrast an essential role in analytical chemistry and bio-medical diagnostics, for which a broad spectrum of micro

  3. hal-00131838,version1-19Feb2007 Electron states of mono-and bilayer graphene on SiC probed by STM

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    hal-00131838,version1-19Feb2007 Electron states of mono- and bilayer graphene on SiC probed by STM to mono- and bilayer graphene capping a C-rich interface. At low temperature, both terraces show ( 3 × 3 close to the Fermi level. We conclude that the metallic states of the first graphene layer are almost

  4. Modelling of noble anaesthetic gases and high hydrostatic pressure effects in lipid bilayers

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

    Moskovitz, Yevgeny [Department of Chemistry, Middle Tennessee State University; Yang, Hui [Department of Chemistry, Middle Tennessee State University

    2015-01-01T23:59:59.000Z

    Our objective was to study molecular processes that might be responsible for inert gas narcosis and high-pressure nervous syndrome. The classical molecular dynamics trajectories (200 ns-long) of dioleoylphosphatidylcholine (DOPC) bilayers simulated by the Berger force field were evaluated for water and the atomic distribution of noble gases around DOPC molecules at a pressure range of 1 - 1000 bar and temperature of 310 Kelvin. Xenon and argon have been tested as model gases for general anesthetics, and neon has been investigated for distortions that are potentially responsible for neurological tremor at hyperbaric conditions. The analysis of stacked radial pair distribution functions of DOPC headgroup atoms revealed the explicit solvation potential of gas molecules, which correlates with their dimensions. The orientational dynamics of water molecules at the biomolecular interface should be considered as an influential factor; while excessive solvation effects appearing in the lumen of membrane-embedded ion channels could be a possible cause of inert gas narcosis. All the noble gases tested exhibit similar patterns of the order parameter for both DOPC acyl chains, which is opposite to the patterns found for the order parameter curve at high hydrostatic pressures in intact bilayers. This finding supports the ‘critical volume’ hypothesis of anesthesia pressure reversal. The irregular lipid headgroup-water boundary observed in DOPC bilayers saturated with neon in the pressure range of 1 - 100 bar could be associated with the possible manifestation of neurological tremor at the atomic scale. The non-immobilizer neon also demonstrated the highest momentum impact on the normal component of the DOPC diffusion coefficient representing monolayers undulations rate, which indicates enhanced diffusivity, rather than atom size, as the key factor.

  5. Modelling of noble anaesthetic gases and high hydrostatic pressure effects in lipid bilayers

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

    Moskovitz, Yevgeny; Yang, Hui

    2015-01-01T23:59:59.000Z

    Our objective was to study molecular processes that might be responsible for inert gas narcosis and high-pressure nervous syndrome. The classical molecular dynamics trajectories (200 ns-long) of dioleoylphosphatidylcholine (DOPC) bilayers simulated by the Berger force field were evaluated for water and the atomic distribution of noble gases around DOPC molecules at a pressure range of 1 - 1000 bar and temperature of 310 Kelvin. Xenon and argon have been tested as model gases for general anesthetics, and neon has been investigated for distortions that are potentially responsible for neurological tremor at hyperbaric conditions. The analysis of stacked radial pair distributionmore »functions of DOPC headgroup atoms revealed the explicit solvation potential of gas molecules, which correlates with their dimensions. The orientational dynamics of water molecules at the biomolecular interface should be considered as an influential factor; while excessive solvation effects appearing in the lumen of membrane-embedded ion channels could be a possible cause of inert gas narcosis. All the noble gases tested exhibit similar patterns of the order parameter for both DOPC acyl chains, which is opposite to the patterns found for the order parameter curve at high hydrostatic pressures in intact bilayers. This finding supports the ‘critical volume’ hypothesis of anesthesia pressure reversal. The irregular lipid headgroup-water boundary observed in DOPC bilayers saturated with neon in the pressure range of 1 - 100 bar could be associated with the possible manifestation of neurological tremor at the atomic scale. The non-immobilizer neon also demonstrated the highest momentum impact on the normal component of the DOPC diffusion coefficient representing monolayers undulations rate, which indicates enhanced diffusivity, rather than atom size, as the key factor.« less

  6. Spin-wave excitation and propagation in microstructured waveguides of yttrium iron garnet/Pt bilayers

    SciTech Connect (OSTI)

    Pirro, P.; Chumak, A. V.; Lägel, B.; Leven, B.; Hillebrands, B. [Fachbereich Physik and Landesforschungszentrum OPTIMAS, Technische Universität Kaiserslautern, D-67663 Kaiserslautern (Germany)] [Fachbereich Physik and Landesforschungszentrum OPTIMAS, Technische Universität Kaiserslautern, D-67663 Kaiserslautern (Germany); Brächer, T. [Fachbereich Physik and Landesforschungszentrum OPTIMAS, Technische Universität Kaiserslautern, D-67663 Kaiserslautern (Germany) [Fachbereich Physik and Landesforschungszentrum OPTIMAS, Technische Universität Kaiserslautern, D-67663 Kaiserslautern (Germany); Graduate School Materials Science in Mainz, Gottlieb-Daimler-Strasse 47, D-67663 Kaiserslautern (Germany); Dubs, C.; Surzhenko, O.; Görnert, P. [Innovent e.V., Prüssingstraße 27B, 07745 Jena (Germany)] [Innovent e.V., Prüssingstraße 27B, 07745 Jena (Germany)

    2014-01-06T23:59:59.000Z

    We present an experimental study of spin-wave excitation and propagation in microstructured waveguides consisting of a 100?nm thick yttrium iron garnet/platinum (Pt) bilayer. The life time of the spin waves is found to be more than an order of magnitude higher than in comparably sized metallic structures, despite the fact that the Pt capping enhances the Gilbert damping. Utilizing microfocus Brillouin light scattering spectroscopy, we reveal the spin-wave mode structure for different excitation frequencies. An exponential spin-wave amplitude decay length of 31??m is observed which is a significant step towards low damping, insulator based micro-magnonics.

  7. Monte-Carlo study of the phase transition in the AA-stacked bilayer graphene

    E-Print Network [OSTI]

    A. A. Nikolaev; M. V. Ulybyshev

    2014-12-04T23:59:59.000Z

    Tight-binding model of the AA-stacked bilayer graphene with screened electron-electron interactions has been studied using the Hybrid Monte Carlo simulations on the original double-layer hexagonal lattice. Instantaneous screened Coulomb potential is taken into account using Hubbard-Stratonovich transformation. G-type antiferromagnetic ordering has been studied and the phase transition with spontaneous generation of the mass gap has been observed. Dependence of the antiferromagnetic condensate on the on-site electron-electron interaction is examined.

  8. Dynamic selective switching in antiferromagnetically-coupled bilayers close to the spin reorientation transition

    E-Print Network [OSTI]

    Fern ández-Pacheco, A.; Ummelen, F. C.; Mansell, R.; Petit, D.; Lee, J. H.; Swagten, H. J. M.; Cowburn, R. P.

    2014-09-05T23:59:59.000Z

    , Phys. Rev. Lett. 98, 117204, (2007). 19P. J. Metaxas, R. L. Stamps, J.-P. Jamet, J. Ferr#2;e, V. Baltz, B. Rodmacq, and P. Politi, Phys. Rev. Lett. 104, 237206 (2010). 20N. Wiese, T. Dimopoulos, M. R€uhrig, J. Wecker, and G. Reiss, J. Appl. Phys. 98... Dynamic selective switching in antiferromagnetically-coupled bilayers close to the spin reorientation transition A. Fernández-Pacheco, F. C. Ummelen, R. Mansell, D. Petit, J. H. Lee, H. J. M. Swagten, and R. P. Cowburn Citation: Applied Physics...

  9. Gates controlled parallel-coupled double quantum dot on both single layer and bilayer graphene

    E-Print Network [OSTI]

    Lin-Jun Wang; Guo-Ping Guo; Da Wei; Gang Cao; Tao Tu; Ming Xiao; Guang-Can Guo; A. M. Chang

    2011-04-22T23:59:59.000Z

    Here we report the fabrication and quantum transport measurements of gates controlled parallel-coupled double quantum dot on both bilayer and single layer graphene. It is shown that the interdot coupling strength of the parallel double dots can be effectively tuned from weak to strong regime by both the in-plane plunger gates and back gate. All the relevant energy scales and parameters of the graphene parallel-coupled double dot can be extracted from the honeycomb charge stability diagrams revealed through the transport measurements.

  10. Distinguishing spin pumping from spin rectification in a Pt/Py bilayer through angle dependent line shape analysis

    SciTech Connect (OSTI)

    Bai, Lihui; Hyde, P.; Hu, C.-M. [Department of Physics and Astronomy, University of Manitoba, Winnipeg R3T 2N2 (Canada)] [Department of Physics and Astronomy, University of Manitoba, Winnipeg R3T 2N2 (Canada); Feng, Z.; Ding, H. F. [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093 (China)] [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093 (China)

    2013-06-17T23:59:59.000Z

    A pure spin current driven by spin pumping is converted to a DC voltage and detected electrically in a Py/Pt bilayer sample. This DC voltage mixes with a DC voltage produced through spin rectification. The ferromagnetic resonance line shape strongly depends on the microwave magnetic h field distribution. We have systematically studied the line shapes by changing the external magnetic field orientation in plane of a Pt/Py bilayer. A method is demonstrated which allows us to calculate the microwave h field vector distribution, and distinguish spin pumping from spin rectification.

  11. Conductivity of Oriented Samaria-Doped Ceria Thin Films Grown...

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

    Conductivity of Oriented Samaria-Doped Ceria Thin Films Grown by Oxygen-plasma-assisted Molecular Beam Epitaxy. Conductivity of Oriented Samaria-Doped Ceria Thin Films Grown by...

  12. First Principles Prediction of Nitrogen-doped Carbon Nanotubes...

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

    First Principles Prediction of Nitrogen-doped Carbon Nanotubes as a High-Performance Cathode for Li-S Batteries. First Principles Prediction of Nitrogen-doped Carbon Nanotubes as a...

  13. Structure, Magnetism and Conductivity in Epitaxial Ti-doped ...

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

    Conductivity in Epitaxial Ti-doped -Fe2O3 Hematite: Experiment and density functional theory Structure, Magnetism and Conductivity in Epitaxial Ti-doped -Fe2O3 Hematite:...

  14. Red-luminescent europium (III) doped silica nanoshells: synthesis,

    E-Print Network [OSTI]

    Kummel, Andrew C.

    Red-luminescent europium (III) doped silica nanoshells: synthesis, characterization(6), 066012 (June 2011) Red-luminescent europium (III) doped silica nanoshells: synthesis, characterization (SPIE). [DOI: 10.1117/1.3593003] Keywords: europium; silica; luminescent; nanoshells; endocytosis. Paper

  15. Metal-doped organic gels and method thereof

    DOE Patents [OSTI]

    Satcher, Jr., Joe H. (Patterson, CA); Baumann, Theodore F. (Tracy, CA)

    2007-10-23T23:59:59.000Z

    Disclosed herein is a sol-gel polymerization process for synthesizing metal-doped organic gels. The process polymerizes metal salts of hydroxylated benzenes or hydroxylated benzene derivatives with alkyl or aryl aldehydes to form metal-doped, wet, organic gels. The gels can then be dried by supercritical solvent extraction to form metal-doped aerogels or by evaporation to form metal-doped xerogels. The aerogels and xerogels can then be pyrolyzed.

  16. Metal-doped organic gels and method thereof

    SciTech Connect (OSTI)

    Satcher Jr., Joe H.; Baumann, Theodore F.

    2003-09-02T23:59:59.000Z

    Disclosed herein is a sol-gel polymerization process for synthesizing metal-doped organic gels. The process polymerizes metal salts of hydroxylated benzenes or hydroxylated benzene derivatives with alkyl or aryl aldehydes to form metal-doped, wet, organic gels. The gels can then be dried by supercritical solvent extraction to form metal-doped aerogels or by evaporation to form metal-doped xerogels. The aerogels and xerogels can then be pyrolyzed.

  17. Doped luminescent materials and particle discrimination using same

    DOE Patents [OSTI]

    Doty, F. Patrick; Allendorf, Mark D; Feng, Patrick L

    2014-10-07T23:59:59.000Z

    Doped luminescent materials are provided for converting excited triplet states to radiative hybrid states. The doped materials may be used to conduct pulse shape discrimination (PSD) using luminescence generated by harvested excited triplet states. The doped materials may also be used to detect particles using spectral shape discrimination (SSD).

  18. Compact, stable 1 ghz femtosecond er-doped fiber lasers

    E-Print Network [OSTI]

    Byun, Hyunil

    We demonstrate a high-repetition-rate soliton fiber laser that is based on highly-doped anomalously-dispersive erbium-doped fiber. By splicing an 11-mm single mode fiber to the erbium-doped fiber, thermal damage of the ...

  19. Intercalation of a Nonionic Surfactant (C10E3) bilayer into a Na-Montmorillonite Clay

    E-Print Network [OSTI]

    Regis Guegan

    2010-11-27T23:59:59.000Z

    A nonionic surfactant, the tri-ethylene glycol mono n-decyl ether (C10E3), characterized by its lamellar phase state, was introduced in the interlayer of a Na-montmorillonite clay at several concentrations. The synthesized organoclays were characterized by Small Angle X-Ray Scattering in conjunction with Fourier Transform Infrared spectroscopy, and adsorption isotherms. Experiments showed that a bilayer of C10E3 was intercalated into the interlayer space of the naturally exchanged Na-montmorillonite, resulting in the aggregation of the lyotropic liquid crystal state in the lamellar phase. This behavior strongly differs from previous observations of confinement of nonionic surfactants in clays where the expansion of the interlayer space was limited to two monolayers parallel to the silicate surface and cationic surfactants in clays where the intercalation of organic compounds is introduced into the clay galleries through ion exchange. The confinement of a bilayer of C10E3 nonionic surfactant in clays offers new perspectives for the realization of hybrid nanomaterials since the synthesized organoclays preserve the electrostatic characteristics of the clays, thus allowing further ion exchange, while presenting at the same time a hydrophobic surface and a maximum opening of the interlayer space for the adsorption of neutral organic molecules of important size with functional properties.

  20. Reduced bleaching in organic nanofibers by bilayer polymer/oxide coating

    SciTech Connect (OSTI)

    Tavares, L.; Kjelstrup-Hansen, J.; Rubahn, H.-G. [NanoSyd, Mads Clausen Institute, University of Southern Denmark, Alsion 2, DK-6400 Soenderborg (Denmark); Sturm, H. [Federal Institute for Materials Research and Testing (BAM), Unter den Eichen 87, D-12205 Berlin (Germany)

    2010-05-15T23:59:59.000Z

    Para-hexaphenylene (p-6P) molecules exhibit a characteristic photoinduced reaction (bleaching) resulting in a decrease in luminescence intensity upon UV light exposure, which could render the technological use of the nanofibers problematic. In order to investigate the photoinduced reaction in nanofibers, optical bleaching experiments have been performed by irradiating both pristine and coated nanofibers with UV light. Oxide coating materials (SiO{sub x} and Al{sub 2}O{sub 3}) were applied onto p-6P nanofibers. These treatments caused a reduction in the bleaching reaction but in addition, the nanofiber luminescence spectrum was significantly altered. It was observed that some polymer coatings [a statistical copolymer of tetrafluoroethylene and 2,2-bis-trifluoromethyl-4,5-difluoro-1,3-dioxole, P(TFE-PDD), and poly(methyl methacrylate), PMMA] do not interfere with the luminescence spectrum from the p-6P but are not effective in stopping the bleaching. Bilayer coatings with first a polymer material, which should work as a protection layer to avoid modifications of the p-6P luminescence spectrum, and second an oxide layer used as oxygen blocker were tested and it was found that a particular bilayer polymer/oxide combination results in a significant reduction in bleaching without affecting significantly the emission spectrum from the nanofibers.

  1. Electric-field-induced plasmon in AA-stacked bilayer graphene

    SciTech Connect (OSTI)

    Chuang, Y.C., E-mail: yingchih.chuang@gmail.com; Wu, J.Y., E-mail: yarst5@gmail.com; Lin, M.F., E-mail: mflin@mail.ncku.edu.tw

    2013-12-15T23:59:59.000Z

    The collective excitations in AA-stacked bilayer graphene for a perpendicular electric field are investigated analytically within the tight-binding model and the random-phase approximation. Such a field destroys the uniform probability distribution of the four sublattices. This drives a symmetry breaking between the intralayer and interlayer polarization intensities from the intrapair band excitations. A field-induced acoustic plasmon thus emerges in addition to the strongly field-tunable intrinsic acoustic and optical plasmons. At long wavelengths, the three modes show different dispersions and field dependence. The definite physical mechanism of the electrically inducible and tunable mode can be expected to also be present in other AA-stacked few-layer graphenes. -- Highlights: •The analytical derivations are performed by the tight-binding model. •An electric field drives the non-uniformity of the charge distribution. •A symmetry breaking between the intralayer and interlayer polarizations is illustrated. •An extra plasmon emerges besides two intrinsic modes in AA-stacked bilayer graphene. •The mechanism of a field-induced mode is present in AA-stacked few-layer graphenes.

  2. Formation and fluidity measurement of supported lipid bilayer on polyvinyl chloride membrane

    SciTech Connect (OSTI)

    Kobayashi, Takuji, E-mail: kobayashi-t@int.ee.tut.ac.jp; Kono, Akiteru, E-mail: kobayashi-t@int.ee.tut.ac.jp; Sawada, Kazuaki [Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka Tempaku-cho, Toyohashi, 441-8580 (Japan); Futagawa, Masato [Department of Electrical and Electronic Information Engineering and Head Office for the Tailor-Made and Baton-Zone Graduate Course, Toyohashi University of Technology, 1-1 Hibarigaoka Tempaku-cho, Toyohashi, 441-8580 (Japan); Tero, Ryugo, E-mail: tero@tut.jp [Electronics-Inspired Interdisciplinary Research Institute and Department of Environmental and Life Sciences, Toyohashi University of Technology, 1-1 Hibarigaoka Tempaku-cho, Toyohashi, 441-8580 (Japan)

    2014-02-20T23:59:59.000Z

    We prepared an artificial lipid bilayer on a plasticized poly(vinyl chloride) (PVC) membrane on a Si3N4 layer deposited on a Si wafer. We optimized the experimental condition for the fabrication of the PVC membrane, and obtained a PVC membrane with a flat and uniform surface on the scale of several hundreds of micrometer suitable for a substrate for supported lipid bilayers (SLBs). The SLB of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) was formed on the PVC membrane by the vesicle fusion method. The observation with a conventional epi-fluorescence microscope and a confocal laser scanning microscope gave geometrically uniform images of the SLB on the PVC membrane. The fluidity and the mobile fraction of the SLB was evaluated by the fluorescence recovery after photobleaching method, and compared with that on a thermally oxidized SiO{sub 2}/Si substrate. The SLB on the PVC membrane contained immobile fraction ?30%, but the diffusion in the mobile fraction was two times faster than that in the SLB on SiO{sub 2}/Si, which had little immobile fraction.

  3. Novel Approach to Conformal FINFET Extension Doping

    SciTech Connect (OSTI)

    Zschaetzsch, G.; Vandervorst, W. [imec Kapeldreef 75, B-3001 Leuven (Belgium); Hoffmann, T. Y.; Horiguchi, N. [Instituut voor Kern- en Stralingsfysica, K.U. Leuven, B-3001 Leuven (Belgium); Hautala, J.; Shao, Y. [TEL Epion Inc., 37 Manning Road, Billerica, MA, 01821 (United States)

    2011-01-07T23:59:59.000Z

    This paper presents a novel strategy to achieve conformal FINFET extension doping with low tilt-angle beam-line ion implantation. The process relies on the self-aligned cap layer formation exclusively on top of the FIN to tune doping levels in this particular area by partial dopant trapping. The conformality itself is evaluated for n- and p-type dopants by a novel extraction method applied to FIN resistor test structures. Furthermore, the process was integrated into a full NMOS device flow and compared to a highly tilted and more conformal As implant condition.

  4. Elastic free-energy of the edge of an open lipid bilayer based on the interactions of its constituent molecules

    E-Print Network [OSTI]

    Meisam Asgari; Aisa Biria

    2015-02-17T23:59:59.000Z

    Lipid-bilayers are the fundamental constituents of the walls of most living cells and lipid vesicles, giving them shape and compartment. The formation and growing of pores in a lipid bilayer have attracted considerable attention from an energetic point of view in recent years. Such pores permit targeted delivery of drugs and genes to the cell, and regulate the concentration of various molecules within the cell. The formation of such pores is caused by various reasons such as changes in cell environment, mechanical stress or thermal fluctuations. Understanding the energy and elastic behaviour of a lipid-bilayer edge is crucial for controlling the formation and growth of such pores. In the present work, the interactions in the molecular level are used to obtain the free energy of the edge of an open lipid bilayer. The resulted free-energy density includes terms associated with flexural and torsional energies of the edge, in addition to a line-tension contribution. The line tension, elastic moduli, and spontaneous normal and geodesic curvatures of the edge are obtained as functions of molecular distribution, molecular dimensions, cutoff distance, and the interaction strength. These parameters are further analyzed by implementing a soft-core interaction potential in the microphysical model. The dependence of the elastic free-energy of the edge to the size of the pore is reinvestigated through an illustrative example, and the results are found to be in agreement with the previous observations.

  5. Alamethicin in lipid bilayers: Combined use of X-ray scattering and MD simulations Jianjun Pan a

    E-Print Network [OSTI]

    Nagle, John F.

    Alamethicin in lipid bilayers: Combined use of X-ray scattering and MD simulations Jianjun Pan of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA d Canadian Neutron Beam Centre:1PC with varying amounts of alamethicin (Alm). We combine the use of X-ray diffuse scattering

  6. Asymmetric distribution of charged lipids between the leaflets of a vesicle bilayer induced by melittin and alamethicin

    SciTech Connect (OSTI)

    Qian, Shuo [ORNL; Heller, William T [ORNL

    2011-01-01T23:59:59.000Z

    Cellular membranes are complex mixtures of lipids, proteins, and other small molecules that provide functional, dynamic barriers between the cell and its environment, as well as between environments within the cell. The lipid composition of the membrane is highly specific and controlled in terms of both content and lipid localization. The membrane structure results from the complex interplay between the wide varieties of molecules present. Here, small-angle neutron scattering and selective deuterium labeling were used to probe the impact of the membrane-active peptides melittin and alamethicin on the structure of lipid bilayers composed of a mixture of the lipids dimyristoyl phosphatidylglycerol (DMPG) and chain-perdeuterated dimyristoyl phosphatidylcholine (DMPC). We found that both peptides enriched the outer leaflet of the bilayer with the negatively charged DMPG, creating an asymmetric distribution of lipids. The level of enrichment is peptide concentration-dependent and is stronger for melittin than it is for alamethicin. The enrichment between the inner and outer bilayer leaflets occurs at very low peptide concentrations and increases with peptide concentration, including when the peptide adopts a membrane-spanning, pore-forming state. The results suggest that these membrane-active peptides may have a secondary stressful effect on target cells at low concentrations that results from a disruption of the lipid distribution between the inner and outer leaflets of the bilayer that is independent of the formation of transmembrane pores.

  7. Localization of Dirac electrons by Moire patterns in graphene bilayers Guy Trambly de Laissardi`ere,1,

    E-Print Network [OSTI]

    Boyer, Edmond

    Localization of Dirac electrons by Moir´e patterns in graphene bilayers Guy Trambly de Laissardi of two Dirac electron gazes coupled by a periodic Hamiltonian such as it appears in rotated graphene´e patterns. PACS numbers: 73.20.-r, 73.20.At, 73.21.Ac, 81.05.Uw Introduction.­ Graphene is a two dimensional

  8. Strain and electric field induced electronic properties of two-dimensional hybrid bilayers of transition-metal dichalcogenides

    SciTech Connect (OSTI)

    Sharma, Munish, E-mail: munishsharmahpu@live.com, E-mail: pk-ahluwalia7@yahoo.com; Kumar, Ashok; Ahluwalia, P. K., E-mail: munishsharmahpu@live.com, E-mail: pk-ahluwalia7@yahoo.com [Department of Physics, Himachal Pradesh University, Shimla 171005 (India); Pandey, Ravindra [Department of Physics, Michigan Technological University, Houghton, Michigan 49931 (United States)

    2014-08-14T23:59:59.000Z

    Tunability of the electronic properties of two-dimensional bilayer hetero structures of transition-metal dichalcogenides (i.e., MX{sub 2}-M?X?{sub 2} with (M, M??=?Mo, W; X, X??=?S, Se) is investigated. Application of both strain and electric field is found to modify the band gap and carrier effective mass in the hybrid bilayers considered. The calculated results based on density functional theory suggest that the tensile strain considerably changes the band gap of semiconducting bilayers; it makes the band gap to be indirect, and later initiates the semiconductor-to-metal transition. Application of the external electric fields, on the other hand, shows asymmetric variation in the band gap leading to the closure of the gap at about 0.5–1.0?V/Å. Tuning of the band gap and carrier effective mass in such a controlled manner makes the hybrid bilayers of transition metal dichalcogenides to be promising candidates for application in electronic devices at nanoscale.

  9. Effects of Palmitoylation on Dynamics and Phospholipid-Bilayer-Perturbing Properties of the N-Terminal Segment of Pulmonary

    E-Print Network [OSTI]

    Pompeu Fabra, Universitat

    Effects of Palmitoylation on Dynamics and Phospholipid-Bilayer- Perturbing Properties of the N-Terminal's, Newfoundland, Canada ABSTRACT It has been proposed that palmitoylation of the N-terminal segment of surfactant membrane models containing palmitoylated and nonpalmitoylated synthetic peptides, based on the N-terminal

  10. Growth of Single-and Bilayer ZnO on Au(111) and Interaction with Xingyi Deng,*,,,

    E-Print Network [OSTI]

    Li, Weixue

    Growth of Single- and Bilayer ZnO on Au(111) and Interaction with Copper Xingyi Deng,*,,§, Kun Yao of Sciences, Dalian 116023, China § URS, P.O. Box 618, South Park, Pennsylvania 15129, United States *S for the structure of the grown ultrathin ZnO, in particular how important the interaction between the substrate

  11. PUBLISHED ONLINE: 11 SEPTEMBER 2011 | DOI: 10.1038/NPHYS2089 Bilayer manganites reveal polarons in the midst of

    E-Print Network [OSTI]

    of bilayer manganites supports a vanishing coherent quasi-particle spectral weight at the Fermi level. This metallic state for x = 0.4 has been shown to support small quasi-particles (QPs) in the spectral function, 3BESSY GmbH, Albert-Einstein-Strasse 15, 12489 Berlin, Germany, 4Paul Scherrer Institute, Swiss

  12. Free energy of the edge of an open lipid bilayer based on the interactions of its constituent molecules

    E-Print Network [OSTI]

    Meisam Asgari; Aisa Biria

    2015-04-05T23:59:59.000Z

    Lipid-bilayers are the fundamental constituents of the walls of most living cells and lipid vesicles, giving them shape and compartment. The formation and growing of pores in a lipid bilayer have attracted considerable attention from an energetic point of view in recent years. Such pores permit targeted delivery of drugs and genes to the cell, and regulate the concentration of various molecules within the cell. The formation of such pores is caused by various reasons such as changes in cell environment, mechanical stress or thermal fluctuations. Understanding the energy and elastic behaviour of a lipid-bilayer edge is crucial for controlling the formation and growth of such pores. In the present work, the interactions in the molecular level are used to obtain the free energy of the edge of an open lipid bilayer. The resulted free-energy density includes terms associated with flexural and torsional energies of the edge, in addition to a line-tension contribution. The line tension, elastic moduli, and spontaneous normal and geodesic curvatures of the edge are obtained as functions of molecular distribution, molecular dimensions, cutoff distance, and the interaction strength. These parameters are further analyzed by implementing a soft-core interaction potential in the microphysical model. The dependence of the elastic free-energy of the edge to the size of the pore is reinvestigated through an illustrative example, and the results are found to be in agreement with the previous observations.

  13. Symmetry Breaking in the Zero-Energy Landau Level in Bilayer Graphene P. Cadden-Zimansky,1,2

    E-Print Network [OSTI]

    Kim, Philip

    Symmetry Breaking in the Zero-Energy Landau Level in Bilayer Graphene Y. Zhao,1 P. Cadden, the eightfold degeneracy in the zero-energy Landau level is completely lifted, exhibiting new quantum Hall precisely at the particle-hole degenerate zero en- ergy. While the energy spacing of SLG LLs scales

  14. Dye-sensitized solar cells based on a nanoparticle/nanotube bilayer structure and their equivalent circuit analysis

    E-Print Network [OSTI]

    Lin, Zhiqun

    Dye-sensitized solar cells based on a nanoparticle/nanotube bilayer structure and their equivalent 2011, Accepted 1st December 2011 DOI: 10.1039/c2nr11617k Dye-sensitized solar cells (DSSCs) were to become an essential component of future global energy production. Dye sensitized solar cells (DSSCs)1

  15. Self-activating and doped tantalate phosphors.

    SciTech Connect (OSTI)

    Nyman, May Devan; Rohwer, Lauren Elizabeth Shea

    2011-01-01T23:59:59.000Z

    An ideal red phosphor for blue LEDs is one of the biggest challenges for the solid-state lighting industry. The appropriate phosphor material should have good adsorption and emission properties, good thermal and chemical stability, minimal thermal quenching, high quantum yield, and is preferably inexpensive and easy to fabricate. Tantalates possess many of these criteria, and lithium lanthanum tantalate materials warrant thorough investigation. In this study, we investigated red luminescence of two lithium lanthanum tantalates via three mechanisms: (1) Eu-doping, (2) Mn-doping and (3) self-activation of the tantalum polyhedra. Of these three mechanisms, Mn-doping proved to be the most promising. These materials exhibit two very broad adsorption peaks; one in the UV and one in the blue region of the spectrum; both can be exploited in LED applications. Furthermore, Mn-doping can be accomplished in two ways; ion-exchange and direct solid-state synthesis. One of the two lithium lanthanum tantalate phases investigated proved to be a superior host for Mn-luminescence, suggesting the crystal chemistry of the host lattice is important.

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

    SciTech Connect (OSTI)

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

    2014-05-07T23:59:59.000Z

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

  17. Perpendicular exchange bias effect in sputter-deposited CoFe/IrMn bilayers

    SciTech Connect (OSTI)

    Chen, J. Y., E-mail: chenjy02@gmail.com; Thiyagarajah, Naganivetha; Xu, H. J.; Coey, J. M. D. [School of Physics and CRANN, Trinity College, Dublin 2 (Ireland)

    2014-04-14T23:59:59.000Z

    CoFe/IrMn bilayers with perpendicular magnetization for various IrMn layer thicknesses exhibit unusual two-step hysteresis loops with both positive and negative loop shifts. Observed at room temperature in the as-grown state, they provide direct evidence of large antiferromagnetic domain formation at the IrMn interface. The exchange bias field reaches 100?mT with an IrMn layer thickness of 4?nm after field annealing at 200?°C–300?°C in 800?mT, which is at least three times as large as the coercivity, and may be useful for reference layers of spin-valves or magnetic tunnel junctions with perpendicular magnetic anisotropy.

  18. Does fluoride disrupt hydrogen bond network in cationic lipid bilayer? Time-dependent fluorescence shift of Laurdan and molecular dynamics simulations

    SciTech Connect (OSTI)

    Pokorna, Sarka; Jurkiewicz, Piotr; Hof, Martin, E-mail: martin.hof@jh-inst.cas.cz [J. Heyrovský Institute of Physical Chemistry of the Academy of Sciences of the Czech Republic v.v.i., Dolejskova 3, 18223 Prague 8 (Czech Republic); Vazdar, Mario [Division of Organic Chemistry and Biochemistry, Rudjer Boškovi? Institute, P.O.B. 180, HR-10002 Zagreb (Croatia); Cwiklik, Lukasz [J. Heyrovský Institute of Physical Chemistry of the Academy of Sciences of the Czech Republic v.v.i., Dolejskova 3, 18223 Prague 8 (Czech Republic); Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16610 Prague 6 (Czech Republic); Jungwirth, Pavel [Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16610 Prague 6 (Czech Republic); Department of Physics, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere (Finland)

    2014-12-14T23:59:59.000Z

    Time-dependent fluorescence shift (TDFS) of Laurdan embedded in phospholipid bilayers reports on hydration and mobility of the phospholipid acylgroups. Exchange of H{sub 2}O with D{sub 2}O prolongs the lifetime of lipid-water and lipid-water-lipid interactions, which is reflected in a significantly slower TDFS kinetics. Combining TDFS measurements in H{sub 2}O and D{sub 2}O hydrated bilayers with atomistic molecular dynamics (MD) simulations provides a unique tool for characterization of the hydrogen bonding at the acylgroup level of lipid bilayers. In this work, we use this approach to study the influence of fluoride anions on the properties of cationic bilayers composed of trimethylammonium-propane (DOTAP). The results obtained for DOTAP are confronted with those for neutral phosphatidylcholine (DOPC) bilayers. Both in DOTAP and DOPC H{sub 2}O/D{sub 2}O exchange prolongs hydrogen-bonding lifetime and does not disturb bilayer structure. These results are confirmed by MD simulations. TDFS experiments show, however, that for DOTAP this effect is cancelled in the presence of fluoride ions. We interpret these results as evidence that strongly hydrated fluoride is able to steal water molecules that bridge lipid carbonyls. Consequently, when attracted to DOTAP bilayer, fluoride disrupts the local hydrogen-bonding network, and the differences in TDFS kinetics between H{sub 2}O and D{sub 2}O hydrated bilayers are no longer observed. A distinct behavior of fluoride is also evidenced by MD simulations, which show different lipid-ion binding for Cl{sup ?} and F{sup ?}.

  19. Cat-doping: Novel method for phosphorus and boron shallow doping in crystalline silicon at 80?°C

    SciTech Connect (OSTI)

    Matsumura, Hideki; Hayakawa, Taro; Ohta, Tatsunori; Nakashima, Yuki; Miyamoto, Motoharu; Thi, Trinh Cham; Koyama, Koichi; Ohdaira, Keisuke [Japan Advanced Institute of Science and Technology (JAIST), Asahidai, Nomi-shi, Ishikawa-ken 923-1292 (Japan)

    2014-09-21T23:59:59.000Z

    Phosphorus (P) or boron (B) atoms can be doped at temperatures as low as 80 to 350?°C, when crystalline silicon (c-Si) is exposed only for a few minutes to species generated by catalytic cracking reaction of phosphine (PH{sub 3}) or diborane (B{sub 2}H{sub 6}) with heated tungsten (W) catalyzer. This paper is to investigate systematically this novel doping method, “Cat-doping”, in detail. The electrical properties of P or B doped layers are studied by the Van der Pauw method based on the Hall effects measurement. The profiles of P or B atoms in c-Si are observed by secondary ion mass spectrometry mainly from back side of samples to eliminate knock-on effects. It is confirmed that the surface of p-type c-Si is converted to n-type by P Cat-doping at 80?°C, and similarly, that of n-type c-Si is to p-type by B Cat-doping. The doping depth is as shallow as 5?nm or less and the electrically activated doping concentration is 10{sup 18} to 10{sup 19?}cm{sup -3} for both P and B doping. It is also found that the surface potential of c-Si is controlled by the shallow Cat-doping and that the surface recombination velocity of minority carriers in c-Si can be enormously lowered by this potential control.

  20. Substrate and method for the formation of continuous magnesium diboride and doped magnesium diboride wire

    DOE Patents [OSTI]

    Suplinskas, Raymond J. (Haverhill, MA); Finnemore, Douglas (Ames, IA); Bud'ko, Serquei (Ames, IA); Canfield, Paul (Ames, IA)

    2007-11-13T23:59:59.000Z

    A chemically doped boron coating is applied by chemical vapor deposition to a silicon carbide fiber and the coated fiber then is exposed to magnesium vapor to convert the doped boron to doped magnesium diboride and a resultant superconductor.

  1. Combustion Synthesis of Doped Thermoelectric Oxides

    SciTech Connect (OSTI)

    Selig, Jiri [Lamar University; Lin, Sidney [Lamar University; Lin, Hua-Tay [ORNL; Johnson, D Ray [ORNL

    2012-01-01T23:59:59.000Z

    Self-propagating high-temperature synthesis (SHS) was used to prepare silver doped calcium cobaltates (Ca1.24- xAgxCo1.62O3.86, x = 0.03 - 0.12) powders. SHS is a simple and economic process to synthesize ceramic materials with minimum energy requirements. The heat generated by the SHS reaction can sustain the propagation of the reaction front and convert reactants to desired products. The effect of doping level on thermoelectric properties was investigated in this study. Results show the substitution of calcium by silver decreases the thermal conductivity significantly. XRD and surface area measurements show synthesized powders are phase pure and have large specific surface areas.

  2. Tungsten-doped thin film materials

    DOE Patents [OSTI]

    Xiang, Xiao-Dong; Chang, Hauyee; Gao, Chen; Takeuchi, Ichiro; Schultz, Peter G.

    2003-12-09T23:59:59.000Z

    A dielectric thin film material for high frequency use, including use as a capacitor, and having a low dielectric loss factor is provided, the film comprising a composition of tungsten-doped barium strontium titanate of the general formula (Ba.sub.x Sr.sub.1-x)TiO.sub.3, where X is between about 0.5 and about 1.0. Also provided is a method for making a dielectric thin film of the general formula (Ba.sub.x Sr.sub.1-x)TiO.sub.3 and doped with W, where X is between about 0.5 and about 1.0, a substrate is provided, TiO.sub.2, the W dopant, Ba, and optionally Sr are deposited on the substrate, and the substrate containing TiO.sub.2, the W dopant, Ba, and optionally Sr is heated to form a low loss dielectric thin film.

  3. Development of photocatalyst by combined nitrogen and yttrium doping

    SciTech Connect (OSTI)

    Khan, Matiullah [Department of Inorganic Nonmetallic Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, 100083 Beijing (China); Department of Physics, University of Science and Technology Bannu, 28100 Bannu (Pakistan); Cao, Wenbin, E-mail: wbcao@ustb.edu.cn [Department of Inorganic Nonmetallic Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, 100083 Beijing (China)

    2014-01-01T23:59:59.000Z

    Graphical abstract: The simulated compensated YN{sub SUB} co-doped TiO{sub 2} model can reasonably explain the experimental observations. Calculation results show that substitutional Y at Ti sites and substitutional N at O sites with an oxygen vacancy give stable configuration, reduced band gap, better visible light absorption and enhance separations of photoexcited charge carriers. The experimental observations confirmed the theoretical findings. - Highlights: • (Y, N) codoped TiO{sub 2} was synthesized by mild one pot hydrothermal method. • The Y doping concentration was varied from 0.01 to 1.38 at%. • 0.05% (Y, N) codoped TiO{sub 2} shows enhanced visible light photocatalytic activity. • Compensated and noncompensated ab-initio calculations were performed. • Calculation results reasonably explained the experimental findings. - Abstract: Titanium dioxide co-doped with yttrium and nitrogen with different yttrium doping concentration has been synthesized by mild one pot hydrothermal method without any post calcination for crystallization. Irrespective of the yttrium doping concentration, all the synthesized samples were composed of pure anatase phase with good crystallinity. And the synthesized co-doped samples have spherical morphology with uniform particle size distribution. The absorption edge of the co-doped TiO{sub 2} was shifted toward visible light region depicting that the intrinsic band gap of TiO{sub 2} was affected by the co-doping. Among the different samples, the co-doped sample with 0.05% yttrium doping concentration exhibits enhanced visible light photocatalytic activity by degradation of methylene blue in aqueous solution. Compensated and non-compensated yttrium–nitrogen co-doped TiO{sub 2} models were simulated using density functional theory to explain the experimental findings. The calculation results show that the compensated yttrium–nitrogen co-doped TiO{sub 2} model may reasonably explain the experimental observations due to its stable configuration, narrowed band gap and enhanced separation of photoexcited carriers.

  4. Photoinduced phenomena in chalcogenide glasses doped with metals

    E-Print Network [OSTI]

    Boolchand, Punit

    on relaxation of photodarkening in a-As2Se3 doped with Sn and rare-earth (RE) ions (Dy, Pr, Hon, Sm3 Nd, Er3 for chalcogenide glasses doped with rare-earth ions as perspective materials for fibre optics amplifiers operating and the kinetics ofphotodarkening in amonhous As2Se3:Sn thin films at %) and and AsSe3 doped with rare-earth ions

  5. Controllable N-Doping of Graphene Beidou Guo,,

    E-Print Network [OSTI]

    Gong, Jian Ru

    ) was fabricated using N-doped graphene and monitored by the source-drain conductance and back-gate voltage (Gsd

  6. Structure-property Relationships in Pure and Doped Epitaxial...

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

    Structure-property Relationships in Pure and Doped Epitaxial Tungsten Trioxide Thin Films Principal Investigator Yingge Du (EMSL) Co-Investigators Ping Yang (EMSL), Rama S. Vemuri...

  7. Electrical and optical properties of gadolinium doped bismuth ferrite nanoparticles

    SciTech Connect (OSTI)

    Mukherjee, A., E-mail: soumen.basu@phy.nitdgp.ac.in; Banerjee, M., E-mail: soumen.basu@phy.nitdgp.ac.in; Basu, S., E-mail: soumen.basu@phy.nitdgp.ac.in [Department of Physics, National Institute of Technology, Durgapur-713209 (India); Pal, M. [CSIR-Central Mechanical Engineering Research Institute, Durgapur-713209 (India)

    2014-04-24T23:59:59.000Z

    Multiferroic bismuth ferrite (BFO) and gadolinium (Gd) doped bismuth ferrite had been synthesized by a sol-gel method. Particle size had been estimated by Transmission electron microscopy (TEM) and found to decrease with Gd doping. We studied the temperature and frequency dependence of impedance and electric modulus and calculated the grain and grain boundary resistance and capacitance of the investigated samples. We observed that electrical activation energy increases for all the doped samples. Optical band gap also increases for the doped samples which can be used in photocatalytic application of BFO.

  8. Boron-doped superlattices and Bragg mirrors in diamond

    SciTech Connect (OSTI)

    Fiori, A. [University of Grenoble Alpes, Inst. NEEL, 38042 Grenoble (France); CNRS, Inst. NEEL, 25 rue des Martyrs, 38042 Grenoble (France); National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Bousquet, J.; Eon, D.; Omnès, F.; Bustarret, E., E-mail: Etienne.bustarret@neel.cnrs.fr [University of Grenoble Alpes, Inst. NEEL, 38042 Grenoble (France); CNRS, Inst. NEEL, 25 rue des Martyrs, 38042 Grenoble (France); Bellet-Amalric, E. [University of Grenoble Alpes, Inst. NEEL, 38042 Grenoble (France); CEA-Grenoble, INAC/SP2M, 17 rue des Martyrs, 38054 Grenoble (France)

    2014-08-25T23:59:59.000Z

    A periodic modulation of the boron doping level of single crystal diamond multilayers over more than three orders of magnitude during epitaxial growth by microwave plasma-enhanced chemical vapor deposition is shown to yield Bragg mirrors in the visible. The thicknesses and doping level of the individual layers were controlled by in situ spectroscopic ellipsometry, enabling to tune the reflectance peak to the wavelength range of diamond color centers, such as NV{sup 0} or NV{sup ?}. The crystalline quality, periodicity, and sharpness of the doping transitions in these doping superlattices over tens of periods were confirmed by high resolution X-ray diffraction.

  9. Photoregulated potassium ion permeation through dihexadecyl phosphate bilayers containing azobenzene and stilbene surfactants

    SciTech Connect (OSTI)

    Lei, Y.; Hurst, J.K. [Washington State Univ., Pullman, WA (United States). Dept. of Chemistry] [Washington State Univ., Pullman, WA (United States). Dept. of Chemistry

    1999-05-11T23:59:59.000Z

    Photoresponsive asymmetrically organized systems based upon small unilamellar dihexadecyl phosphate (DHP) vehicles were constructed by entrapping high concentrations of potassium ion within the vesicular aqueous core and incorporating either an amphiphilic trans-azobenzene-containing phosphate monoester or an amphiphilic trans-stilbene-containing carboxylic acid into its membrane structure. Spectroscopic measurements indicated that the azobenzene derivative was molecularly dispersed in the hydrocarbon phase of the vesicle and that the extent of aggregation of the membrane-localized stilbene derivative was minor. Thermal K{sup +} leak rates from the doped vesicles were very low, with calculated permeability coefficients (P) of {approximately}4 {times} 10{sup {minus}12} cm/s at 40 C for DHP vesicles containing 5.5 mol % of the trans-azobenzene derivative and {approximately}1.5 {times} 10{sup {minus}11} cm/s at 38 C for vesicles containing 5.5 mol % of the trans-stilbene derivative; for comparison, P {approx_equal} 2 {times} 10{sup {minus}12} cm/s for undoped vesicles at 40 C. Photoexcitation of the azobenzene-doped vesicles at 360 nm caused >90% trans {r_arrow} cis photoisomerization over the measured temperature range (25--40 C), with complete reversion to the trans isomer upon photoexcitation at 450 nm. Photoexcitation of deoxygenated suspensions of the stilbene-doped vesicles at 315 nm gave {approximately}80% conversion to the cis isomer in the photostationary state, which was not reversible. At 25 C, K{sup +} leak rates for the isomeric azobenzene-doped vesicles were nearly identical; at 40 C, K{sup +} leakage for the DHP vesicles containing the cis-azobenzene isomer corresponded to P {approx_equal} 2 {times} 10{sup {minus}11} cm/s, 5-fold greater than that of the trans isomer. In trans {r_arrow} cis {r_arrow} trans photocycling experiments, K{sup +} leak rates alternately increased and decreased, indicating that the vesicles remained intact. At 40 C, K{sup +} leakage from the vesicles containing predominantly cis-stilbene was {approximately}2-fold greater than that from vesicles with the corresponding trans isomer. In electrochemical experiments, viologen-mediated reduction of the DHP-bound trans-azobenzene occurred at E < {minus}0.44 V, with hydrazobenzene reoxidation at E {approx_equal} {minus}0.16 V; addition of viologen radicals to aqueous suspensions of the trans-azobenzene-doped DHP vesicles caused immediate decolorization of the dye.

  10. Soft X-Ray Spectroscopic Study of Dense Strontium-Doped Lanthanum...

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

    Spectroscopic Study of Dense Strontium-Doped Lanthanum Manganite Cathodes for Solid Oxide Fuel Cell Applications. Soft X-Ray Spectroscopic Study of Dense Strontium-Doped Lanthanum...

  11. In Situ One-Step Synthesis of Hierarchical Nitrogen-Doped Porous...

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

    Synthesis of Hierarchical Nitrogen-Doped Porous Carbon for High Performance Supercapacitors. In Situ One-Step Synthesis of Hierarchical Nitrogen-Doped Porous Carbon for High...

  12. Spectral Control of Emission from Tin Doped Targets for Extreme Ultraviolet Lithography

    E-Print Network [OSTI]

    2006-01-01T23:59:59.000Z

    control of emissions from tin doped targets for extremearray (UTA) emission around 13.5 nm from solid density tinand tin doped foam targets. Extreme ultraviolet (EUV)

  13. Arrangement of Annexin A2 tetramer and its impact on the structure and diffusivity of supported lipid bilayers

    E-Print Network [OSTI]

    Kirstin Fritz; Georg Fritz; Barbara Windschiegl; Claudia Steinem; Bert Nickel

    2010-09-16T23:59:59.000Z

    Annexins are a family of proteins that bind to anionic phospholipid membranes in a Ca2+-dependent manner. Annexin A2 forms heterotetramers (Anx A2t) with the S100A10 (p11) protein dimer. The tetramer is capable of bridging phospholipid membranes and it has been suggested to play a role in Ca2+-dependent exocytosis and cell-cell adhesion of metastatic cells. Here, we employ x-ray reflectivity measurements to resolve the conformation of Anx A2t upon Ca2+-dependent binding to single supported lipid bilayers (SLBs) composed of different mixtures of anionic (POPS) and neutral (POPC) phospholipids. Based on our results we propose that Anx A2t binds in a side-by-side configuration, i.e., both Anx A2 monomers bind to the bilayer with the p11 dimer positioned on top. Furthermore, we observe a strong decrease of lipid mobility upon binding of Anx A2t to SLBs with varying POPS content. X-ray reflectivity measurements indicate that binding of Anx A2t also increases the density of the SLB. Interestingly, in the protein-facing leaflet of the SLB the lipid density is higher than in the substrate-facing leaflet. This asymmetric densification of the lipid bilayer by Anx A2t and Ca2+ might have important implications for the biochemical mechanism of Anx A2t-induced endo- and exocytosis.

  14. Single Ion Implantation and Deterministic Doping

    SciTech Connect (OSTI)

    Schenkel, Thomas

    2010-06-11T23:59:59.000Z

    The presence of single atoms, e.g. dopant atoms, in sub-100 nm scale electronic devices can affect the device characteristics, such as the threshold voltage of transistors, or the sub-threshold currents. Fluctuations of the number of dopant atoms thus poses a complication for transistor scaling. In a complementary view, new opportunities emerge when novel functionality can be implemented in devices deterministically doped with single atoms. The grand price of the latter might be a large scale quantum computer, where quantum bits (qubits) are encoded e.g. in the spin states of electrons and nuclei of single dopant atoms in silicon, or in color centers in diamond. Both the possible detrimental effects of dopant fluctuations and single atom device ideas motivate the development of reliable single atom doping techniques which are the subject of this chapter. Single atom doping can be approached with top down and bottom up techniques. Top down refers to the placement of dopant atoms into a more or less structured matrix environment, like a transistor in silicon. Bottom up refers to approaches to introduce single dopant atoms during the growth of the host matrix e.g. by directed self-assembly and scanning probe assisted lithography. Bottom up approaches are discussed in Chapter XYZ. Since the late 1960's, ion implantation has been a widely used technique to introduce dopant atoms into silicon and other materials in order to modify their electronic properties. It works particularly well in silicon since the damage to the crystal lattice that is induced by ion implantation can be repaired by thermal annealing. In addition, the introduced dopant atoms can be incorporated with high efficiency into lattice position in the silicon host crystal which makes them electrically active. This is not the case for e.g. diamond, which makes ion implantation doping to engineer the electrical properties of diamond, especially for n-type doping much harder then for silicon. Ion implantation is usually a highly statistical process, where high fluences of energetic ions, ranging from {approx}10{sup 9} to >10{sup 16} cm{sup -2} are implanted. For single atom device development, control over the absolute number of ions is needed and ions have to be placed with high spatial resolution. In the following sections we will discuss a series of approaches to single ion implantation with regard to single ion impact sensing and control of single ion positioning.

  15. Design for a single mode erbium-doped fiber laser

    E-Print Network [OSTI]

    Wang, Jon-En

    1995-01-01T23:59:59.000Z

    The objective of this research was to design and fabricate a single-mode, narrow-linewidth linear erbium-doped fiber laser using a solid etalon for mode selection. This thesis describes the design of the linear laser which uses erbium-doped fiber...

  16. Femtosecond Laser Ablation of Silicon: Nanoparticles, Doping and Photovoltaics

    E-Print Network [OSTI]

    Mazur, Eric

    Femtosecond Laser Ablation of Silicon: Nanoparticles, Doping and Photovoltaics A thesis presented Laser Ablation of Silicon: Nanoparticles, Doping and Photovoltaics Eric Mazur Brian R. Tull Abstract irradiated surface layer to the grain boundaries. #12;iv Lastly, we measure the photovoltaic properties

  17. Design for a single mode erbium-doped fiber laser 

    E-Print Network [OSTI]

    Wang, Jon-En

    1995-01-01T23:59:59.000Z

    The objective of this research was to design and fabricate a single-mode, narrow-linewidth linear erbium-doped fiber laser using a solid etalon for mode selection. This thesis describes the design of the linear laser which uses erbium-doped fiber...

  18. Europium-doped yttrium silicate nanophosphors prepared by flame synthesis

    E-Print Network [OSTI]

    Bernhard, Stefan

    Europium-doped yttrium silicate nanophosphors prepared by flame synthesis Xiao Qin a,*, Yiguang Ju; accepted 7 November 2006 Available online 22 December 2006 Abstract Europium-doped yttrium silicate (Y2SiO5 properties 1. Introduction Yttrium silicate (Y2SiO5) is an important luminescent host material for various

  19. Superlattice doped layers for amorphous silicon photovoltaic cells

    DOE Patents [OSTI]

    Arya, Rajeewa R. (Doylestown, PA)

    1988-01-12T23:59:59.000Z

    Superlattice doped layers for amorphous silicon photovoltaic cells comprise a plurality of first and second lattices of amorphous silicon alternatingly formed on one another. Each of the first lattices has a first optical bandgap and each of the second lattices has a second optical bandgap different from the first optical bandgap. A method of fabricating the superlattice doped layers also is disclosed.

  20. Polarization controllable Fresnel lens using dye-doped liquid crystals

    E-Print Network [OSTI]

    Wu, Shin-Tson

    Polarization controllable Fresnel lens using dye- doped liquid crystals Tsung-Hsien Lin,1,2 Yuhua controllable Fresnel zone plate lens is demonstrated using a photo-induced alignment of the dye-doped liquid. X. Ren, S. Liu, and X. Zhang, "Fabrication of off-axis holographic Fresnel lens used as multiplexer

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

    E-Print Network [OSTI]

    Wu, Junqiao

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

  2. Impurity Doping Effect in High T c Superconductors

    E-Print Network [OSTI]

    Impurity Doping Effect in High T c Superconductors Yong­Jihn Kim and K. J. Chang Department observed that impurity doping and/or ion­beam­induced dam­ age in high T c superconductors cause a metal­ calization effect on superconductivity, we examine the variation of T c with increasing of impurity

  3. Tailoring coercivity of unbiased exchange-coupled ferromagnet/antiferromagnet bilayers

    SciTech Connect (OSTI)

    Sossmeier, K. D.; Schafer, D.; Bastos, A. P. O.; Schmidt, J. E.; Geshev, J. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, 91501-970 Rio Grande do Sul (Brazil)

    2012-07-01T23:59:59.000Z

    This paper reports experimental results obtained on unconventional exchange-coupled ferromagnet/antiferromagnet (FM/AF) system showing zero net bias. The Curie temperature of the FM (NiCu) is lower than the blocking temperature of the AF (IrMn). Samples were either annealed or irradiated with He, Ar, or Ge ions at 40 keV. Due to the exchange coupling at the FM/AF interface, the coercivity (H{sub C}) of the as-deposited FM/AF bilayer is rather higher than that of the corresponding FM single layer. We found that by choosing a proper ion fluence or annealing temperature, it is possible to controllably vary H{sub C}. Ion irradiation of the FM single layer has lead to only a decrease of H{sub C} and annealing or He ion irradiation has not caused important changes at the FM/AF interface; nevertheless, a twofold increase of H{sub C} was obtained after these treatments. Even more significant enhancement of H{sub C} was attained after Ge ion irradiation and attributed to ion-implantation-induced modification of only the FM layer; damages of the FM/AF interface, on the other hand, decrease the coercivity.

  4. Coexistence and competition of nematic and gapped states in bilayer graphene

    E-Print Network [OSTI]

    E. V. Gorbar; V. P. Gusynin; V. A. Miransky; I. A. Shovkovy

    2012-09-24T23:59:59.000Z

    In bilayer graphene, the phase diagram in the plane of a strain-induced bare nematic term, ${\\cal N}_{0}$, and a top-bottom gates voltage imbalance, $U_{0}$, is obtained by solving the gap equation in the random-phase approximation. At nonzero ${\\cal N}_0$ and $U_0$, the phase diagram consists of two hybrid spin-valley symmetry-broken phases with both nontrivial nematic and mass-type order parameters. The corresponding phases are separated by a critical line of first- and second-order phase transitions at small and large values of ${\\cal N}_0$, respectively. The existence of a critical end point, where the line of first-order phase transitions terminates, is predicted. For ${\\cal N}_0=0$, a pure gapped state with a broken spin-valley symmetry is the ground state of the system. As ${\\cal N}_{0}$ increases, the nematic order parameter increases, and the gap weakens in the hybrid state. For $U_{0}=0$, a quantum second-order phase transition from the hybrid state into a pure gapless nematic state occurs when the strain reaches a critical value. A nonzero $U_{0}$ suppresses the critical value of the strain. The relevance of these results to recent experiments is briefly discussed.

  5. Quantum radiations from exciton condensate in Electron-Hole Bilayer Systems

    E-Print Network [OSTI]

    Jinwu Ye; T. Shi; Longhua Jiang; C. P. Sun

    2009-07-10T23:59:59.000Z

    Superfluid has been realized in Helium-4, Helium-3 and ultra-cold atoms. It has been widely used in making high-precision devices and also in cooling various systems. There have been extensive experimental search for possible exciton superfluid (ESF) in semiconductor electron-hole bilayer (EHBL) systems below liquid Helium temperature. However, exciton superfluid are meta-stable and will eventually decay through emitting photons. Here we study quantum nature of photons emitted from the excitonic superfluid (ESF) phase in the semiconductor EHBL and find that the light emitted from the excitonic superfluid has unique and unusual features not shared by any other atomic or condensed matter systems. We show that the emitted photons along the direction perpendicular to the layer are in a coherent state, those along all tilted directions are in a two modes squeezed state. We determine the two mode squeezing spectra, the angle resolved power spectrum, the line shapes of both the momentum distribution curve (MDC) and the energy distribution curve (EDC). From the two photon correlation functions, we find there are photon bunching, the photo-count statistics is super-Poissonian. We discuss how several important parameters such as the chemical potential, the exciton decay rate, the quasiparticle energy spectrum and the dipole-dipole interaction strength between the excitons in our theory can be extracted from the experimental data and comment on available experimental data on both EDC and MDC.

  6. Neutron scattering from myelin revisited: bilayer asymmetry and water-exchange kinetics

    SciTech Connect (OSTI)

    Denninger, Andrew R. [Boston College, Chestnut Hill, MA 02467 (United States); Demé, Bruno; Cristiglio, Viviana [Institut Laue–Langevin (ILL), CS 20156, F-38042 Grenoble CEDEX 9 (France); LeDuc, Géraldine [European Synchrotron Radiation Facility (ESRF), CS 40220, F-38043 Grenoble CEDEX 9 (France); Feller, W. Bruce [NOVA Scientific Inc., Sturbridge, MA 01566 (United States); Kirschner, Daniel A., E-mail: kirschnd@bc.edu [Boston College, Chestnut Hill, MA 02467 (United States)

    2014-12-01T23:59:59.000Z

    The structure of internodal myelin in the rodent central and peripheral nervous systems has been determined using neutron diffraction. The kinetics of water exchange in these tissues is also described. Rapid nerve conduction in the central and peripheral nervous systems (CNS and PNS, respectively) of higher vertebrates is brought about by the ensheathment of axons with myelin, a lipid-rich, multilamellar assembly of membranes. The ability of myelin to electrically insulate depends on the regular stacking of these plasma membranes and on the presence of a number of specialized membrane-protein assemblies in the sheath, including the radial component, Schmidt–Lanterman incisures and the axo–glial junctions of the paranodal loops. The disruption of this fine-structure is the basis for many demyelinating neuropathies in the CNS and PNS. Understanding the processes that govern myelin biogenesis, maintenance and destabilization requires knowledge of myelin structure; however, the tight packing of internodal myelin and the complexity of its junctional specializations make myelin a challenging target for comprehensive structural analysis. This paper describes an examination of myelin from the CNS and PNS using neutron diffraction. This investigation revealed the dimensions of the bilayers and aqueous spaces of myelin, asymmetry between the cytoplasmic and extracellular leaflets of the membrane, and the distribution of water and exchangeable hydrogen in internodal multilamellar myelin. It also uncovered differences between CNS and PNS myelin in their water-exchange kinetics.

  7. Asymmetric Electron Transport at Monolayer-Bilayer Heterojunctions of Epitaxial Graphene

    SciTech Connect (OSTI)

    Li, An-Ping [ORNL] [ORNL; Clark, Kendal W [ORNL] [ORNL; Zhang, Xiaoguang [ORNL] [ORNL; Gu, Gong [University of Tennessee, Knoxville (UTK)] [University of Tennessee, Knoxville (UTK); He, Guowei [Carnegie Mellon University (CMU)] [Carnegie Mellon University (CMU); Feenstra, Randall [Carnegie Mellon University (CMU)] [Carnegie Mellon University (CMU)

    2014-01-01T23:59:59.000Z

    The symmetry of the graphene honeycomb lattice is a key element determining many of graphene s unique electronic properties, such as the linear energy-momentum dispersion and the suppressed backscattering 1,2. However, line defects in large-scale epitaxial graphene films, such as grain boundaries, edges, surface steps, and changes in layer thickness, often break the sublatttice symmetry and can impact transport properties of graphene profoundly 3-6. Here we report asymmetric electron transport upon polarity reversal at individual monolayer-bilayer (ML-BL) boundaries in epitaxial graphene on SiC (0001), revealed by scanning tunneling potentiometry. A greater voltage drop is observed when the current flows from BL to ML graphene than in the reverse direction, and the difference remains nearly unchanged with increasing current. This is not a typical nonlinear conductance due to electron transmission through an asymmetric potential. Rather, it indicates the opening of a dynamic energy gap at the Fermi energy due to the Coulomb interaction between the injected nonequilibrium electron density and the pseudospin polarized Friedel oscillation charge density at the boundary. This intriguing heterojunction transport behavior opens a new avenue towards novel quantum functions such as quantum switching.

  8. Field Theoretic Study of Bilayer Membrane Fusion: II. Mechanism of a Stalk-Hole Complex

    E-Print Network [OSTI]

    Kirill Katsov; Marcus Mueller; Michael Schick

    2005-07-19T23:59:59.000Z

    We use self-consistent field theory to determine structural and energetic properties of intermediates and transition states involved in bilayer membrane fusion. In particular, we extend our original calculations from those of the standard hemifusion mechanism, which was studied in detail in the first paper of this series, to consider a possible alternative to it. This mechanism involves non-axial stalk expansion, in contrast to the axially symmetric evolution postulated in the classical mechanism. Elongation of the initial stalk facilitates the nucleation of holes and leads to destabilization of the fusing membranes via the formation of a stalk-hole complex. We study properties of this complex in detail, and show how transient leakage during fusion, previously predicted and recently observed in experiment, should vary with system architecture and tension. We also show that the barrier to fusion in the alternative mechanism is lower than that of the standard mechanism by a few $k_BT$ over most of the relevant region of system parameters, so that this alternative mechanism is a viable alternative to the standard pathway.

  9. Nanostructured bilayered vanadium oxide electrodes for rechargeable sodium-ion batteries.

    SciTech Connect (OSTI)

    Tepavcevic, S.; Xiong, H.; Stamenkovic, V.R.; Zuo, X.; Balasubramanian, M.; Prakapenka, V.B.; Johnson, C.S.; Rajh, T. (Accelerator Systems Division (APS)); ( CNM); ( MSD); (University of Chicago)

    2012-01-01T23:59:59.000Z

    Tailoring nanoarchitecture of materials offers unprecedented opportunities in utilization of their functional properties. Nanostructures of vanadium oxide, synthesized by electrochemical deposition, are studied as a cathode material for rechargeable Na-ion batteries. Ex situ and in situ synchrotron characterizations revealed the presence of an electrochemically responsive bilayered structure with adjustable intralayer spacing that accommodates intercalation of Na{sup +} ions. Sodium intake induces organization of overall structure with appearance of both long- and short-range order, while deintercalation is accompanied with the loss of long-range order, whereas short-range order is preserved. Nanostructured electrodes achieve theoretical reversible capacity for Na{sub 2}V{sub 2}O{sub 5} stoichiometry of 250 mAh/g. The stability evaluation during charge-discharge cycles at room temperature revealed an efficient 3 V cathode material with superb performance: energy density of {approx}760 Wh/kg and power density of 1200 W/kg. These results demonstrate feasibility of development of the ambient temperature Na-ion rechargeable batteries by employment of electrodes with tailored nanoarchitectures.

  10. Effect of stacking sequence on crystallization in Al/a-Ge bilayer thin films

    SciTech Connect (OSTI)

    Zhang, Tianwei; Zhang, Weilin; Ma, Fei, E-mail: mafei@mail.xjtu.edu.cn, E-mail: kwxu@mail.xjtu.edu.cn [State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, Shaanxi 710049 (China); Huang, Yuhong [College of Physics and Information Technology, Shaanxi Normal University, Xi'an, Shaanxi 710062 (China); Xu, Kewei, E-mail: mafei@mail.xjtu.edu.cn, E-mail: kwxu@mail.xjtu.edu.cn [State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China and Department of Physics and Opt-electronic Engineering, Xi'an University of Arts and Science, Xi'an, Shaanxi 710065 (China)

    2014-05-15T23:59:59.000Z

    Two types of bilayer thin films with different deposition sequences, i.e., amorphous Ge under Al (a-Ge/Al) and the inverse (Al/a-Ge), were prepared by magnetron sputtering at room temperature. In-situ and ex-situ thermal annealing were compared to study the effect of the stacking sequence on crystallization of amorphous Ge. Although metal-induced crystallization occurred in both cases at low temperature, layer exchange was observed only in a-Ge/Al. In fact, compressive stress could usually be produced when Ge atoms diffused into Al grain boundaries and crystallized there. In the a-Ge/Al system, the stress could be released through diffusion of Al atoms onto the surface and formation of hillocks. Thus, grain boundary (GB) mediated crystallization was dominant in the whole process and layer exchange occurred. However, in the Al/a-Ge system, it was difficult for stress to be relaxed because the Ge sublayer and substrate restricted the diffusion of Al atoms. GB-mediated crystallization was, therefore, considerably suppressed and interface-mediated crystallization was preferred without layer exchange. This leads to distinct morphologies of dendrites in the two systems.

  11. Nitrogen doped zinc oxide thin film

    SciTech Connect (OSTI)

    Li, Sonny X.

    2003-12-15T23:59:59.000Z

    To summarize, polycrystalline ZnO thin films were grown by reactive sputtering. Nitrogen was introduced into the films by reactive sputtering in an NO{sub 2} plasma or by N{sup +} implantation. All ZnO films grown show n-type conductivity. In unintentionally doped ZnO films, the n-type conductivities are attributed to Zn{sub i}, a native shallow donor. In NO{sub 2}-grown ZnO films, the n-type conductivity is attributed to (N{sub 2}){sub O}, a shallow double donor. In NO{sub 2}-grown ZnO films, 0.3 atomic % nitrogen was found to exist in the form of N{sub 2}O and N{sub 2}. Upon annealing, N{sub 2}O decomposes into N{sub 2} and O{sub 2}. In furnace-annealed samples N{sub 2} redistributes diffusively and forms gaseous N{sub 2} bubbles in the films. Unintentionally doped ZnO films were grown at different oxygen partial pressures. Zni was found to form even at oxygen-rich condition and led to n-type conductivity. N{sup +} implantation into unintentionally doped ZnO film deteriorates the crystallinity and optical properties and leads to higher electron concentration. The free electrons in the implanted films are attributed to the defects introduced by implantation and formation of (N{sub 2}){sub O} and Zni. Although today there is still no reliable means to produce good quality, stable p-type ZnO material, ZnO remains an attractive material with potential for high performance short wavelength optoelectronic devices. One may argue that gallium nitride was in a similar situation a decade ago. Although we did not obtain any p-type conductivity, we hope our research will provide a valuable reference to the literature.

  12. Scintillation of rare earth doped fluoride nanoparticles

    SciTech Connect (OSTI)

    Jacobsohn, L. G.; McPherson, C. L.; Sprinkle, K. B.; Ballato, J. [Center for Optical Materials Science and Engineering Technologies (COMSET), and School of Materials Science and Engineering, Clemson University, Clemson, South Carolina 29634 (United States); Yukihara, E. G. [Physics Department, Oklahoma State University, Stillwater, Oklahoma 74078-3072 (United States); DeVol, T. A. [Department of Environmental Engineering and Earth Sciences, Clemson University, Clemson, South Carolina 29634-0905 (United States)

    2011-09-12T23:59:59.000Z

    The scintillation response of rare earth (RE) doped core/undoped (multi-)shell fluoride nanoparticles was investigated under x-ray and alpha particle irradiation. A significant enhancement of the scintillation response was observed with increasing shells due: (i) to the passivation of surface quenching defects together with the activation of the REs on the surface of the core nanoparticle after the growth of a shell, and (ii) to the increase of the volume of the nanoparticles. These results are expected to reflect a general aspect of the scintillation process in nanoparticles, and to impact radiation sensing technologies that make use of nanoparticles.

  13. LASER TRANSFER DOPING USING AMORPHOUS SILICON Rafel Ferr (Correspondence author)1

    E-Print Network [OSTI]

    LASER TRANSFER DOPING USING AMORPHOUS SILICON Rafel Ferré (Correspondence author)1 , Ralf Gogolin1@isfh.de ABSTRACT: We demonstrate and characterize "Laser Transfer Doping" (LTD) for producing locally doped regions. For this purpose we use nanosecond pulsed laser for transferring phosphorus doped amorphous silicon from a carrier

  14. Structural Detuning of Pump Absorption Rate in Doped Fiber for the Enhancement of Power Conversion Efficiency

    E-Print Network [OSTI]

    Park, Namkyoo

    Structural Detuning of Pump Absorption Rate in Doped Fiber for the Enhancement of Power Conversion Doped Fiber Amplifier. With proper adjustments on doping profiles for the reduction of pump absorption rate, it becomes possible to optimize pump evolution map inside the doped fiber to get better power

  15. Color stable manganese-doped phosphors

    DOE Patents [OSTI]

    Lyons, Robert Joseph (Burnt Hills, NY); Setlur, Anant Achyut (Niskayuna, NY); Deshpande, Anirudha Rajendra (Twinsburg, OH); Grigorov, Ljudmil Slavchev (Sofia, BG)

    2012-08-28T23:59:59.000Z

    A process for preparing color stable Mn.sup.+4 doped phosphors includes providing a phosphor of formula I; A.sub.x[MF.sub.y]:Mn.sup.+4 I and contacting the phosphor in particulate form with a saturated solution of a composition of formula II in aqueous hydrofluoric acid; A.sub.x[MF.sub.y]; II wherein A is Li, Na, K, Rb, Cs, NR.sub.4 or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; R is H, lower alkyl, or a combination thereof; x is the absolute value of the charge of the [MF.sub.y] ion; and y is 5, 6 or 7. In particular embodiments, M is Si, Ge, Sn, Ti, Zr, or a combination thereof. A lighting apparatus capable of emitting white light includes a semiconductor light source; and a phosphor composition radiationally coupled to the light source, and which includes a color stable Mn.sup.+4 doped phosphor.

  16. Transparent conducting oxides: A -doped superlattice approach

    SciTech Connect (OSTI)

    Cooper, Valentino R [ORNL; Seo, Sung Seok A. [University of Kentucky, Lexington; Lee, Suyoun [ORNL; Kim, Jun Sung [Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea; Choi, Woo Seok [ORNL; Okamoto, Satoshi [ORNL; Lee, Ho Nyung [ORNL

    2014-01-01T23:59:59.000Z

    Two-dimensional electron gases (2DEGs) at the interface of oxide heterostructures have been the subject of recent experiment and theory, due to the intriguing phenomena that occur in confined electronic states. However, while much has been done to understand the origin of 2DEGs and related phenomena, very little has been explored with regards to the control of conduction pathways and the distribution of charge carriers. Using first principles simulations and experimental thin film synthesis methods, we examine the effect of dimensionality on carrier transport in La delta-doped SrTiO3 (STO) superlattices, as a function of the thickness of the insulating STO spacer. Our computed Fermi surfaces and layer-resolved carrier density proles demonstrate that there is a critical thickness of the STO spacer, below which carrier transport is dominated by three-dimensional conduction of interface charges arising from appreciable overlap of the quantum mechanical wavefunctions between neighboring delta-doped layers. We observe that, experimentally, these superlattices remain highly transparent to visible light. Band structure calculations indicate that this is a result of the appropriately large gap between the O 2p and Ti d states. The tunability of the quantum mechanical wavefunctions and the optical transparency highlight the potential for using oxide heterostructures in novel opto-electronic devices; thus providing a route to the creation of novel transparent conducting oxides.

  17. Multilayered gold/silica nanoparticulate bilayer devices using layer-by-layer self organisation for flexible bending and pressure sensing applications

    SciTech Connect (OSTI)

    Shah Alam, Md. [Department of Electrical and Electronic Engineering, Rajshahi University of Engineering and Technology, Rajshahi 6204 (Bangladesh); Center of Excellence in Nanotechnology, Asian Institute of Technology, 12120 Pathumthani (Thailand); Mohammed, Waleed S., E-mail: waleed.m@bu.ac.th [Center of Research in Optoelectronics, Communication and Control System (BU-CROCCS), School of Engineering, Bangkok University, Pathumthani 12120 (Thailand); Dutta, Joydeep, E-mail: dutta@squ.edu.om [Center of Excellence in Nanotechnology, Asian Institute of Technology, 12120 Pathumthani (Thailand); Chair in Nanotechnology, Water Research Center, Sultan Qaboos University, P.O. Box 33, Al Khoud 123 (Oman)

    2014-02-17T23:59:59.000Z

    A pressure and bending sensor was fabricated using multilayer thin films fabricated on a flexible substrate based on layer-by-layer self-organization of 18?nm gold nanoparticles separated by a dielectric layer of 30?nm silica nanoparticles. 50, 75, and 100 gold-silica bi-layered films were deposited and the device characteristics were studied. A threshold voltage was required for electron conduction which increases from 2.4?V for 50 bi-layers to 3.3?V for 100 bi-layers. Upon bending of the device up to about 52°, the threshold voltage and slope of the I-V curves change linearly. Electrical characterization of the multilayer films was carried out under ambient conditions with different pressures and bending angles in the direct current mode. This study demonstrates that the developed multilayer thin films can be used as pressure as well as bending sensing applications.

  18. Growth and characterization of Sc-doped EuO thin films

    SciTech Connect (OSTI)

    Altendorf, S. G.; Reisner, A.; Chang, C. F.; Hollmann, N.; Rata, A. D.; Tjeng, L. H. [Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187 Dresden (Germany)

    2014-02-03T23:59:59.000Z

    The preparation of 3d-transition metal-doped EuO thin films by molecular beam epitaxy is investigated using the example of Sc doping. The Sc-doped EuO samples display a good crystalline structure, despite the relatively small ionic radius of the dopant. The Sc doping leads to an enhancement of the Curie temperature to up to 125?K, remarkably similar to previous observations on lanthanide-doped EuO.

  19. Electron density analysis of the effects of sugars on the structure of lipid bilayers at low hydration - a preliminary study

    SciTech Connect (OSTI)

    Lenné, T.; Kent, B.; Koster, K.L.; Garvey, C.J.; Bryant, G. (ANSTO); (USD); (ANU); (RMIT)

    2012-02-06T23:59:59.000Z

    Small angle X-ray scattering is used to study the effects of sugars on membranes during dehydration. Previous work has shown that the bilayer and chain-chain repeat spacings of DPPC bilayers are relatively unaffected by the presence of sugars. In this work we present a preliminary analysis of the electron density profiles of DPPC in the presence of sugars at low hydration. The difficulties of determining the correct phasing are discussed. Sugars and other small solutes have been shown to have an important role in improving the tolerance of a range of species to desiccation and freezing. In particular it has been shown that sugars can stabilize membranes in the fluid membrane phase during dehydration, and in the fully dehydrated state. Equivalently, at a particular hydration, the presence of sugars lowers the transition temperature between the fluid and gel phases. There are two competing models for explaining the effects of sugars on membrane phase transition temperatures. One, designated the water replacement hypothesis (WRH) states that sugars hydrogen bond to phospholipid headgroups, thus hindering the fluid-gel phase transition. One version of this model suggests that certain sugars (such as trehalose) achieve the measured effects by inserting between the phospholipid head groups. An alternative model explains the observed effects of sugars in terms of the sugars effect on the hydration repulsion that develops between opposing membranes during dehydration. The hydration repulsion leads to a lateral compressive stress in the bilayer which squeezes adjacent lipids more closely together, resulting in a transition to the gel phase. When sugars are present, their osmotic and volumetric effects reduce the hydration repulsion, reduce the compressive stress in the membranes, and therefore tend to maintain the average lateral separation between lipids. This model is called the hydration forces explanation (HFE). We recently showed that neither mono- nor di-saccharides affect the average distance between lipid chains in the bilayer, supporting the predictions of the HFE. In this paper we further investigate the effects of sugars on membrane structure by conducting electron density analysis of recent data. This preliminary analysis sheds additional light onto the effects of sugars on membrane structure.

  20. Quantum electrodynamics with anisotropic scaling: Heisenberg-Euler action and Schwinger pair production in the bilayer graphene

    E-Print Network [OSTI]

    M. I. Katsnelson; G. E. Volovik

    2012-03-19T23:59:59.000Z

    We discuss quantum electrodynamics emerging in the vacua with anisotropic scaling. Systems with anisotropic scaling were suggested by Horava in relation to the quantum theory of gravity. In such vacua the space and time are not equivalent, and moreover they obey different scaling laws, called the anisotropic scaling. Such anisotropic scaling takes place for fermions in bilayer graphene, where if one neglects the trigonal warping effects the massless Dirac fermions have quadratic dispersion. This results in the anisotropic quantum electrodynamics, in which electric and magnetic fields obey different scaling laws. Here we discuss the Heisenberg-Euler action and Schwinger pair production in such anisotropic QED

  1. Self-doped molecular composite battery electrolytes

    DOE Patents [OSTI]

    Harrup, Mason K.; Wertsching, Alan K.; Stewart, Frederick F.

    2003-04-08T23:59:59.000Z

    This invention is in solid polymer-based electrolytes for battery applications. It uses molecular composite technology, coupled with unique preparation techniques to render a self-doped, stabilized electrolyte material suitable for inclusion in both primary and secondary batteries. In particular, a salt is incorporated in a nano-composite material formed by the in situ catalyzed condensation of a ceramic precursor in the presence of a solvated polymer material, utilizing a condensation agent comprised of at least one cation amenable to SPE applications. As such, the counterion in the condensation agent used in the formation of the molecular composite is already present as the electrolyte matrix develops. This procedure effectively decouples the cation loading levels required for maximum ionic conductivity from electrolyte physical properties associated with condensation agent loading levels by utilizing the inverse relationship discovered between condensation agent loading and the time domain of the aging step.

  2. Muon spin depolarization in nonmagnetic metals doped with paramagnetic impurities

    SciTech Connect (OSTI)

    Heffner, R.H.

    1980-01-01T23:59:59.000Z

    The diffusion of muons and their magnetic interactions are treated by describing the physics to be learned from experiments which measure muon depolarization in metallic hosts doped with dilute concentrations of magnetic impurities. (GHT)

  3. Fluorine compounds for doping conductive oxide thin films

    DOE Patents [OSTI]

    Gessert, Tim; Li, Xiaonan; Barnes, Teresa M; Torres, Jr., Robert; Wyse, Carrie L

    2013-04-23T23:59:59.000Z

    Methods of forming a conductive fluorine-doped metal oxide layer on a substrate by chemical vapor deposition are described. The methods may include heating the substrate in a processing chamber, and introducing a metal-containing precursor and a fluorine-containing precursor to the processing chamber. The methods may also include adding an oxygen-containing precursor to the processing chamber. The precursors are reacted to deposit the fluorine-doped metal oxide layer on the substrate. Methods may also include forming the conductive fluorine-doped metal oxide layer by plasma-assisted chemical vapor deposition. These methods may include providing the substrate in a processing chamber, and introducing a metal-containing precursor, and a fluorine-containing precursor to the processing chamber. A plasma may be formed that includes species from the metal-containing precursor and the fluorine-containing precursor. The species may react to deposit the fluorine-doped metal oxide layer on the substrate.

  4. 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 ...

  5. Self-doping effects in epitaxially grown graphene

    E-Print Network [OSTI]

    Siegel, David A.

    2009-01-01T23:59:59.000Z

    The electronic properties of graphene, Rev. Mod. Phys. (inE?ects in Epitaxially-Grown Graphene D.A. Siegel, 1, 2 S.Y.2009) Abstract Self-doping in graphene has been studied by

  6. Chiral superconductivity from repulsive interactions in doped graphene

    E-Print Network [OSTI]

    Chubukov, A. V.

    Chiral superconductivity, which breaks time-reversal symmetry, can exhibit a wealth of fascinating properties that are highly sought after for nanoscience applications. We identify doped graphene monolayer as a system where ...

  7. apical oxygen doping: Topics by E-print Network

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

    kinetics ofphotodarkening in amonhous As2Se3:Sn thin films at %) and and AsSe3 doped with rare-earth ions Boolchand, Punit 166 Topological Gauge Structure and Phase Diagram for...

  8. atomic nitrogen doping: Topics by E-print Network

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

    Chris Greene 3:30 - 3:50 Nick Brewer, Wisconsin, Left-handed electromagnetic waves in rare-earth doped Kemner, Ken 154 4, 26412665, 2007 Nitrogen retention Physics Websites...

  9. Step-edge-induced resistance anisotropy in quasi-free-standing bilayer chemical vapor deposition graphene on SiC

    SciTech Connect (OSTI)

    Ciuk, Tymoteusz [Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland); Institute of Microelectronics and Optoelectronics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw (Poland); Cakmakyapan, Semih; Ozbay, Ekmel [Department of Electrical and Electronics Engineering, Department of Physics, Nanotechnology Research Center, Bilkent University, 06800 Bilkent, Ankara (Turkey); Caban, Piotr; Grodecki, Kacper; Pasternak, Iwona; Strupinski, Wlodek, E-mail: wlodek.strupinski@itme.edu.pl [Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland); Krajewska, Aleksandra [Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland); Institute of Optoelectronics, Military University of Technology, Gen. S. Kaliskiego 2, 00-908 Warsaw (Poland); Szmidt, Jan [Institute of Microelectronics and Optoelectronics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw (Poland)

    2014-09-28T23:59:59.000Z

    The transport properties of quasi-free-standing (QFS) bilayer graphene on SiC depend on a range of scattering mechanisms. Most of them are isotropic in nature. However, the SiC substrate morphology marked by a distinctive pattern of the terraces gives rise to an anisotropy in graphene's sheet resistance, which may be considered an additional scattering mechanism. At a technological level, the growth-preceding in situ etching of the SiC surface promotes step bunching which results in macro steps ~10 nm in height. In this report, we study the qualitative and quantitative effects of SiC steps edges on the resistance of epitaxial graphene grown by chemical vapor deposition. We experimentally determine the value of step edge resistivity in hydrogen-intercalated QFS-bilayer graphene to be ~190 ??m for step height hS = 10 nm and provide proof that it cannot originate from mechanical deformation of graphene but is likely to arise from lowered carrier concentration in the step area. Our results are confronted with the previously reported values of the step edge resistivity in monolayer graphene over SiC atomic steps. In our analysis, we focus on large-scale, statistical properties to foster the scalable technology of industrial graphene for electronics and sensor applications.

  10. Arrangement of Annexin A2 tetramer and its impact on the structure and diffusivity of supported lipid bilayers

    E-Print Network [OSTI]

    Fritz, Kirstin; Windschiegl, Barbara; Steinem, Claudia; Nickel, Bert; 10.1039/c0sm00047g

    2010-01-01T23:59:59.000Z

    Annexins are a family of proteins that bind to anionic phospholipid membranes in a Ca2+-dependent manner. Annexin A2 forms heterotetramers (Anx A2t) with the S100A10 (p11) protein dimer. The tetramer is capable of bridging phospholipid membranes and it has been suggested to play a role in Ca2+-dependent exocytosis and cell-cell adhesion of metastatic cells. Here, we employ x-ray reflectivity measurements to resolve the conformation of Anx A2t upon Ca2+-dependent binding to single supported lipid bilayers (SLBs) composed of different mixtures of anionic (POPS) and neutral (POPC) phospholipids. Based on our results we propose that Anx A2t binds in a side-by-side configuration, i.e., both Anx A2 monomers bind to the bilayer with the p11 dimer positioned on top. Furthermore, we observe a strong decrease of lipid mobility upon binding of Anx A2t to SLBs with varying POPS content. X-ray reflectivity measurements indicate that binding of Anx A2t also increases the density of the SLB. Interestingly, in the protein-fa...

  11. Doped carbon nanostructure field emitter arrays for infrared imaging

    DOE Patents [OSTI]

    Korsah, Kofi (Knoxville, TN) [Knoxville, TN; Baylor, Larry R (Farragut, TN) [Farragut, TN; Caughman, John B (Oak Ridge, TN) [Oak Ridge, TN; Kisner, Roger A (Knoxville, TN) [Knoxville, TN; Rack, Philip D (Knoxville, TN) [Knoxville, TN; Ivanov, Ilia N (Knoxville, TN) [Knoxville, TN

    2009-10-27T23:59:59.000Z

    An infrared imaging device and method for making infrared detector(s) having at least one anode, at least one cathode with a substrate electrically connected to a plurality of doped carbon nanostructures; and bias circuitry for applying an electric field between the anode and the cathode such that when infrared photons are adsorbed by the nanostructures the emitted field current is modulated. The detectors can be doped with cesium to lower the work function.

  12. Trench process and structure for backside contact solar cells with polysilicon doped regions

    DOE Patents [OSTI]

    De Ceuster, Denis; Cousins, Peter John; Smith, David D

    2013-05-28T23:59:59.000Z

    A solar cell includes polysilicon P-type and N-type doped regions on a backside of a substrate, such as a silicon wafer. An interrupted trench structure separates the P-type doped region from the N-type doped region in some locations but allows the P-type doped region and the N-type doped region to touch in other locations. Each of the P-type and N-type doped regions may be formed over a thin dielectric layer. Among other advantages, the resulting solar cell structure allows for increased efficiency while having a relatively low reverse breakdown voltage.

  13. Trench process and structure for backside contact solar cells with polysilicon doped regions

    DOE Patents [OSTI]

    De Ceuster, Denis; Cousins, Peter John; Smith, David D

    2014-03-18T23:59:59.000Z

    A solar cell includes polysilicon P-type and N-type doped regions on a backside of a substrate, such as a silicon wafer. An interrupted trench structure separates the P-type doped region from the N-type doped region in some locations but allows the P-type doped region and the N-type doped region to touch in other locations. Each of the P-type and N-type doped regions may be formed over a thin dielectric layer. Among other advantages, the resulting solar cell structure allows for increased efficiency while having a relatively low reverse breakdown voltage.

  14. Tunable electronic structures of p-type Mg doping in AlN nanosheet

    SciTech Connect (OSTI)

    Peng, Yuting; Xia, Congxin, E-mail: xiacongxin@htu.edu.cn; Zhang, Heng; Wang, Tianxing; Wei, Shuyi [Department of Physics, Henan Normal University, Xinxiang, Henan 453007 (China); Jia, Yu [School of Physics and Engineering, Zhengzhou University, Zhengzhou 450052 (China)

    2014-07-28T23:59:59.000Z

    The p-type impurity properties are investigated in the Mg-doped AlN nanosheet by means of first-principles calculations. Numerical results show that the transition energy levels reduce monotonously with the increase in Mg doping concentration in the Mg-doped AlN nanosheet systems, and are lower than that of the Mg-doped bulk AlN case for the cases with larger doping concentration. Moreover, Mg substituting Al atom is energy favorably under N-rich growth experimental conditions. These results are new and interesting to further improve p-type doping efficiency in the AlN nanostructures.

  15. Trench process and structure for backside contact solar cells with polysilicon doped regions

    DOE Patents [OSTI]

    De Ceuster, Denis (Woodside, CA); Cousins, Peter John (Menlo Park, CA); Smith, David D. (Campbell, CA)

    2010-12-14T23:59:59.000Z

    A solar cell includes polysilicon P-type and N-type doped regions on a backside of a substrate, such as a silicon wafer. An interrupted trench structure separates the P-type doped region from the N-type doped region in some locations but allows the P-type doped region and the N-type doped region to touch in other locations. Each of the P-type and N-type doped regions may be formed over a thin dielectric layer. Among other advantages, the resulting solar cell structure allows for increased efficiency while having a relatively low reverse breakdown voltage.

  16. CVD Growth of Mono-and Bi-Layer Graphene from Ethanol Xiao Chen, Pei Zhao, Bo Hou, Erik Einarsson, Shohei Chiashi and Shigeo Maruyama

    E-Print Network [OSTI]

    Maruyama, Shigeo

    CVD Growth of Mono- and Bi-Layer Graphene from Ethanol Xiao Chen, Pei Zhao, Bo Hou, Erik Einarsson precursors have been employed to synthesize graphene, such as methane [6], ethane [7] and ethanol [8]. Here we report a systematic study on CVD growth of graphene on Cu and Ni substrates from ethanol. Ethanol

  17. Electron transfer through a lipid-bilayer-membrane-aqueous-solution interface and kinetics of the oxidation of viologen radicals in homogeneous and vesicular systems

    SciTech Connect (OSTI)

    Shafirovich, V.Ya.; Levin, P.P.; Khannanov, N.K.; Kuz'min, V.A.

    1986-10-10T23:59:59.000Z

    The purpose of the present work was to study the influence of the nature of the oxidizing agent on the rate constant of the oxidation of viologen radicals in homogeneous and vesicular systems by water-soluble oxidizing agents. In this work the authors used the following water-soluble viologens: methyl viologen, sulfoethyl viologen, trimethylaminopropyl viologen, and octadecyl viologen, which is soluble only in a lipid bilayer. The rate constant for the oxidation of a viologen radical cation in a lipid bilayer by electron acceptors in the aqueous phase, in contrast to the homogeneous reaction, is lower than the rate constant of the diffusion-controlled reaction. The rate of electron transfer on the interface is determined by the interaction of the reactants with the lipid bilayer. The rate constant for electron transfer from a viologen radical cation near the inner surface of a lipid bilayer to viologen near the outer surface with the formation of a radical which is available for oxidation in the external aqueous phase has been determined and has been found to be independent of the nature of the oxidizing agent.

  18. In-situ high resolution transmission electron microscopy observation of silicon nanocrystal nucleation in a SiO{sub 2} bilayered matrix

    SciTech Connect (OSTI)

    Yang, T. C.-J., E-mail: terry.yang@unsw.edu.au; Wu, L.; Lin, Z.; Jia, X.; Puthen-Veettil, B.; Zhang, T.; Conibeer, G.; Perez-Wurfl, I. [School of Photovoltaic and Renewable Engineering, University of New South Wales, Sydney, New South Wales 2052 (Australia); Kauffmann, Y.; Rothschild, A. [Department of Materials Science and Engineering, Technion – Israel Institute of Technology, Technion City, Haifa 32000 (Israel)

    2014-08-04T23:59:59.000Z

    Solid-state nucleation of Si nanocrystals in a SiO{sub 2} bilayered matrix was observed at temperatures as low as 450?°C. This was achieved by aberration corrected high-resolution transmission electron microscopy (HRTEM) with real-time in-situ heating up to 600?°C. This technique is a valuable characterization tool especially with the recent interest in Si nanostructures for light emitting devices, non-volatile memories, and third-generation photovoltaics which all typically require a heating step in their fabrication. The control of size, shape, and distribution of the Si nanocrystals are critical for these applications. This experimental study involves in-situ observation of the nucleation of Si nanocrystals in a SiO{sub 2} bilayered matrix fabricated through radio frequency co-sputtering. The results show that the shapes of Si nanocrystals in amorphous SiO{sub 2} bilayered matrices are irregular and not spherical, in contrast to many claims in the literature. Furthermore, the Si nanocrystals are well confined within their layers by the amorphous SiO{sub 2}. This study demonstrates the potential of in-situ HRTEM as a tool to observe the real time nucleation of Si nanocrystals in a SiO{sub 2} bilayered matrix. Furthermore, ideas for improvements on this in-situ heating HRTEM technique are discussed.

  19. Interfacing 2D and 3D Topological Insulators: Bi(111) Bilayer on Bi2Te3 Toru Hirahara,1,* Gustav Bihlmayer,2

    E-Print Network [OSTI]

    Hasegawa, Shuji

    Interfacing 2D and 3D Topological Insulators: Bi(111) Bilayer on Bi2Te3 Toru Hirahara,1,* Gustav Topological insulators, realized in materials with strong spin-orbit interaction, are gaining increasing-dimensional (1D) edge states compared to the 2D surface states of 3D topological insulators, only a few works

  20. Time-resolved FTIR spectroscopy for monitoring protein dynamics exemplified by functional studies of Ras protein bound to a lipid bilayer

    E-Print Network [OSTI]

    Gerwert, Klaus

    bilayers can be investigated in near physiological con- ditions with the attenuated total reflection (ATR online 22 August 2011 Keywords: Infrared Time-resolved Difference spectroscopy Rapid scan Step scan GTPases GTP Caged-substances Ras Isotopic labeling Band assignment Global fit Attenuated total reflection

  1. Conformational plasticity of the influenza A M2 transmembrane helix in lipid bilayers under varying pH, drug binding, and membrane thickness

    E-Print Network [OSTI]

    Hong, Mei

    Conformational plasticity of the influenza A M2 transmembrane helix in lipid bilayers under varying cues, thus conformational plasticity is important for function. The influenza A M2 protein forms spectroscopy to examine the conformational plasticity of membrane-bound transmembrane domain of M2 (M2TM). 13 C

  2. Water-Protein Interactions of an Arginine-Rich Membrane Peptide in Lipid Bilayers Investigated by Solid-State Nuclear Magnetic Resonance Spectroscopy

    E-Print Network [OSTI]

    Hong, Mei

    Water-Protein Interactions of an Arginine-Rich Membrane Peptide in Lipid Bilayers InvestigatedVised Manuscript ReceiVed: February 16, 2010 The interaction of an arginine (Arg) residue with water HETCOR experiments, we unambiguously assigned a water-guanidinium cross-peak that is distinct from

  3. Repulsive van der Waals forces due to hydrogen exposure on bilayer Graphene

    E-Print Network [OSTI]

    Mathias Boström; Bo E. Sernelius

    2012-01-05T23:59:59.000Z

    We consider the effect of atomic hydrogen exposure to a system of two undoped sheets of graphene grown near a silica surface (the first adsorbed to the surface and the second freestanding near the surface). In the absence of atomic hydrogen the van der Waals force between the sheets is attractive at all separations causing the sheets to come closer together. However, with addition of atomic hydrogen between the sheets the long range van der Waals interaction turns repulsive at a critical concentration. The underlying triple layer structure (SiO2 -Atomic Hydrogen Gas -Air) gives rise to a long range repulsion that at large enough separations dominates over the more rapidly decaying attraction between the two-dimensional undoped graphene sheets (and between the outer graphene sheet and SiO2). This may be an avenue to tune the separation between two graphene sheets with the gas concentration. Doping of the graphene layers increases the attractive part of the interaction and hence reduces the net repulsive interaction.

  4. Color stable manganese-doped phosphors

    DOE Patents [OSTI]

    Lyons, Robert Joseph; Setlur, Anant Achyut; Deshpande, Anirundha Rajendra; Grigorov, Ljudmil Slavchev

    2014-04-29T23:59:59.000Z

    A lighting apparatus capable of emitting white light includes a semiconductor light source; and a phosphor material radiationally coupled to the light source. The phosphor material includes a color-stable Mn.sup.+4 doped phosphor prepared by a process including providing a phosphor of formula I; A.sub.x[MF.sub.y]:Mn.sup.+4 I and contacting the phosphor in particulate form with a saturated solution of a composition of formula II in aqueous hydrofluoric acid; A.sub.x[MF.sub.y]; II wherein A is Li, Na, K, Rb, Cs, NR.sub.4 or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; R is H, lower alkyl, or a combination thereof; x is the absolute value of the charge of the [MF.sub.y] ion; and y is 5, 6 or 7. In particular embodiments, M is Si, Ge, Sn, Ti, Zr, or a combination thereof.

  5. Electrical transport properties of Ti-doped Fe2O3(0001) epitaxial...

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

    Electrical transport properties of Ti-doped Fe2O3(0001) epitaxial films. Electrical transport properties of Ti-doped Fe2O3(0001) epitaxial films. Abstract: The electrical transport...

  6. Hafnium-doped tantalum oxide high-k gate dielectric films for future CMOS technology 

    E-Print Network [OSTI]

    Lu, Jiang

    2007-04-25T23:59:59.000Z

    A novel high-k gate dielectric material, i.e., hafnium-doped tantalum oxide (Hf-doped TaOx), has been studied for the application of the future generation metal-oxidesemiconductor field effect transistor (MOSFET). The ...

  7. Fe-doped InN layers grown by molecular beam epitaxy

    SciTech Connect (OSTI)

    Wang Xinqiang; Liu Shitao; Ma Dingyu; Zheng Xiantong; Chen Guang; Xu Fujun; Tang Ning; Shen Bo [State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China); Zhang Peng; Cao Xingzhong; Wang Baoyi [State Key Laboratory of Nuclear Analysis Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Huang Sen; Chen, Kevin J. [Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology (Hong Kong); Zhou Shengqiang [Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01314 Dresden (Germany); Yoshikawa, Akihiko [Center for SMART Green Innovation Research, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan)

    2012-10-22T23:59:59.000Z

    Iron(Fe)-doped InN (InN:Fe) layers have been grown by molecular beam epitaxy. It is found that Fe-doping leads to drastic increase of residual electron concentration, which is different from the semi-insulating property of Fe-doped GaN. However, this heavy n-type doping cannot be fully explained by doped Fe-concentration ([Fe]). Further analysis shows that more unintentionally doped impurities such as hydrogen and oxygen are incorporated with increasing [Fe] and the surface is degraded with high density pits, which probably are the main reasons for electron generation and mobility reduction. Photoluminescence of InN is gradually quenched by Fe-doping. This work shows that Fe-doping is one of good choices to control electron density in InN.

  8. Fluorine doping in dilute magnetic semiconductor Sn1–xFexO2...

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

    Fluorine doping in dilute magnetic semiconductor Sn1–xFexO2. Fluorine doping in dilute magnetic semiconductor Sn1–xFexO2. Abstract: Recent studies have reported...

  9. The Synthesis of Ag-Doped Mesoporous TiO2 . | EMSL

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

    TiO2 . The Synthesis of Ag-Doped Mesoporous TiO2 . Abstract: Ag-doped mesoporous titanium oxide was prepared using non-ionic surfactants and easily handled titanium...

  10. Ti(III) Doped Titanium Dioxide: an Effective Strategy to Improve the Visible Light Photocatalytic Activity

    E-Print Network [OSTI]

    Zuo, Fan

    2012-01-01T23:59:59.000Z

    types of surface titanium and oxygen atoms present. PageRIVERSIDE Ti(III) Doped Titanium Dioxide: an EffectiveDISSERTATION Ti(III) Doped Titanium Dioxide: an Effective

  11. The Synthesis of Cadmium Doped Mesoporous TiO2. | EMSL

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

    TiO2. The Synthesis of Cadmium Doped Mesoporous TiO2. Abstract: Cd doped mesoporous titanium oxide was prepared using non-ionic surfactants and easily handled titanium...

  12. Iron (III) Chloride doping of large-area chemical vapor deposition graphene

    E-Print Network [OSTI]

    Song, Yi, S.M. Massachusetts Institute of Technology

    2013-01-01T23:59:59.000Z

    Chemical doping is an effective method of reducing the sheet resistance of graphene. This thesis aims to develop an effective method of doping large area Chemical Vapor Deposition (CVD) graphene using Iron (III) Chloride ...

  13. Influence of samaria doping on the resistance of ceria thin films...

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

    doping on the resistance of ceria thin films and its implications to the planar oxygen sensing devices. Influence of samaria doping on the resistance of ceria thin films and...

  14. Growth of Cr-doped TiO Films in the Rutile and Anatase Structures...

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

    of Cr-doped TiO Films in the Rutile and Anatase Structures by Oxygen Plasma Assisted Molecular Beam Epitaxy . Growth of Cr-doped TiO Films in the Rutile and Anatase Structures by...

  15. Room-Temperature Ferromagnetism in Ion-Implanted Co-Doped TiO...

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

    Room-Temperature Ferromagnetism in Ion-Implanted Co-Doped TiO(110) Rutile. Room-Temperature Ferromagnetism in Ion-Implanted Co-Doped TiO(110) Rutile. Abstract: Interest in diluted...

  16. Synthesis of Room-Temperature Ferromagnetic Cr-doped TiO(110...

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

    Room-Temperature Ferromagnetic Cr-doped TiO(110) Rutile Single Crystals using Ion Implantation. Synthesis of Room-Temperature Ferromagnetic Cr-doped TiO(110) Rutile Single Crystals...

  17. Room Temperature Ferromagnetism in Ion-implanted Co-doped TiO...

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

    Room Temperature Ferromagnetism in Ion-implanted Co-doped TiO(110) Rutile. Room Temperature Ferromagnetism in Ion-implanted Co-doped TiO(110) Rutile. Abstract: Ferromagnetic...

  18. Systematic investigation and in vitro biocompatibility studies on mesoporous europium doped hydroxyapatite

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Systematic investigation and in vitro biocompatibility studies on mesoporous europium doped on europium doped hydroxyapatite (Eu:HAp). In this work, a set of complementary techniques Fourier Transform: nanoparticles, hydroxyapatite, europium, in vitro studies 1. Introduction Hydroxyapatite (HAp) is one

  19. Role of dye structure in photoinduced reorientation of dye-doped liquid crystals

    E-Print Network [OSTI]

    Marrucci, Lorenzo

    -doped nematic liquid crystals has been measured for a homologous set of dyes belonging to the anthraquinone

  20. ccsd-00018793,version3-28Apr2006 Doping quantum dimer models on the square lattice

    E-Print Network [OSTI]

    Boyer, Edmond

    . Evidence for an extended region of a doped VBS phase exhibiting holon pairing but no phase separation

  1. Bulk optical damage thresholds for doped and undoped, crystalline and ceramic yttrium aluminum garnet

    SciTech Connect (OSTI)

    Do, Binh T.; Smith, Arlee V.

    2009-06-20T23:59:59.000Z

    We measured the bulk optical damage thresholds of pure and Nd-doped ceramic yttrium aluminum garnet (YAG), and of pure, Nd-doped, Cr-doped, and Yb-doped crystalline YAG. We used 9.9 ns, 1064 nm, single-longitudinal mode, TEM00 pulses, to determine that the breakdown thresholds are deterministic, with multiple-pulse thresholds ranging from 1.1 to 2.2 kJ/cm{sup 2}.

  2. Time-resolved X-ray diffraction studies of laser-induced acoustic wave propagation in bilayer metallic thin crystals

    SciTech Connect (OSTI)

    Er, Ali Oguz [Department of Physics and Astronomy, Western Kentucky University, Bowling Green, Kentucky 42101 (United States); Tang, Jau, E-mail: jautang@gate.sinica.edu.tw, E-mail: prentzepis@ece.tamu.edu [Research Center for Applied Sciences Academia Sinica, Taipei, Taiwan (China); Chen, Jie [Key Laboratory for Laser Plasmas (Ministry of Education) and Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Rentzepis, Peter M., E-mail: jautang@gate.sinica.edu.tw, E-mail: prentzepis@ece.tamu.edu [Department of Electrical and Computer Engineering, Texas A and M University, College Station, Texas 77843 (United States)

    2014-09-07T23:59:59.000Z

    Phonon propagation across the interface of a Cu/Ag(111) bilayer and transient lattice disorder, induced by a femtosecond 267?nm pulse, in Ag(111) crystal have been measured by means of time resolved X-ray diffraction. A “blast” force due to thermal stress induced by suddenly heated electrons is formed within two picoseconds after excitation and its “blast wave” propagation through the interface and Ag (111) crystal was monitored by the shift and broadening of the rocking curve, I vs. ?, as a function of time after excitation. Lattice disorder, contraction and expansion as well as thermal strain formation and wave propagation have also been measured. The experimental data and mechanism proposed are supported by theoretical simulations.

  3. Excitons in a mirror: Formation of “optical bilayers” using MoS{sub 2} monolayers on gold substrates

    SciTech Connect (OSTI)

    Mertens, Jan; Baumberg, Jeremy J., E-mail: jjb12@cam.ac.uk [Nanophotonics Centre, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE (United Kingdom); Shi, Yumeng; Yang, Hui Ying, E-mail: yanghuiying@sutd.edu.sg [Pillar of Engineering Product Development, Singapore University of Technology and Design, Singapore 138682 (Singapore); Molina-Sánchez, Alejandro; Wirtz, Ludger [Physics and Materials Science Research Unit, University of Luxembourg, L-1511 Luxembourg (Luxembourg)

    2014-05-12T23:59:59.000Z

    We report coupling of excitons in monolayers of molybdenum disulphide to their mirror image in an underlying gold substrate. Excitons at the direct band gap are little affected by the substrate whereas strongly bound C-excitons associated with a van-Hove singularity change drastically. On quartz substrates only one C-exciton is visible (in the blue) but on gold substrates a strong red-shifted extra resonance in the green is seen. Exciton coupling to its image leads to formation of a “mirror biexciton” with enhanced binding energy. Estimates of this energy shift in an emitter-gold system match experiments well. The absorption spectrum of MoS{sub 2} on gold thus resembles a bilayer of MoS{sub 2} which has been created by optical coupling. Additional top-mirrors produce an “optical bulk.”.

  4. Emission properties of heterostructures with a (GaAsSb-InGaAs)/GaAs bilayer quantum well

    SciTech Connect (OSTI)

    Zvonkov, B. N.; Nekorkin, S. M.; Vikhrova, O. V.; Dikareva, N. V., E-mail: dikareva@nifti.unn.ru [Nizhni Novgorod State University, Physical-Technical Research Institute (Russian Federation)

    2013-09-15T23:59:59.000Z

    The specific features of the emission characteristics of GaAs-based heterostructures with a GaAs{sub 1-x}Sb{sub x}-In{sub y}Ga{sub 1-y}As bilayer quantum well are studied. The heterostructures are grown by metal-organic chemical vapor deposition (MOCVD). With an analysis of previously reported data on the MOCVD growth process taken into account, the temperature range (560-580 Degree-Sign C), the relation between the fluxes emitted by the sources of Group-V and -III elements ( Less-Than-Or-Equivalent-To 1), and the order of layer growth for the production of the active region of a GaAs/InGaP laser heterostructure are determined experimentally. The active region is a GaAs{sub 0.75}Sb{sub 0.25}-In{sub 0.2}Ga{sub 0.8}As bilayer quantum well. For the structure, a 1075-nm electroluminescence signal attributed to indirect transitions between the valence band of the GaAs{sub 0.75}Sb{sub 0.25} layer and the conduction band of the In{sub 0.2}Ga{sub 0.8}As layer is observed. An increase in the continuous-wave pump current yields a decrease in the 1075-nm emission intensity and initiates stable lasing at a wavelength of 1022 nm at a threshold current density of 1.4 kA cm{sup -2} at room temperature. Lasing occurs at transitions direct in coordinate space.

  5. Nanocrystal bilayer for tandem catalysis Yusuke Yamada1, Chia-Kuang Tsung1,2, Wenyu Huang1,2, Ziyang Huo1, Susan E. Habas1,2,

    E-Print Network [OSTI]

    Yang, Peidong

    , propanal was produced selectively from methanol and ethylene on the nanocrystal bilayer tandem catalyst-generation energy conversion and storage technol- ogies1,2 . Although industrial catalysts can be optimized

  6. Electrochemical studies of moderately boron doped polycrystalline diamond in non-aqueous solvent

    E-Print Network [OSTI]

    Bristol, University of

    Electrochemical studies of moderately boron doped polycrystalline diamond in non-aqueous solvent being marketed [83,84]. The first paper on the electrochemistry of boron doped polycrystalline diamond The electrochemistry of boron doped diamond is currently an active field of research. In the majority of studies

  7. Spatially-Correlated Microstructure and Superconductivity in Polycrystalline Boron-Doped Diamond

    E-Print Network [OSTI]

    Spatially-Correlated Microstructure and Superconductivity in Polycrystalline Boron-Doped Diamond F tunneling spectroscopies are performed below 100 mK on nano-crystalline boron-doped diamond films been discovered in heavily doped group IV covalent semicon- ductors [1], in particular diamond [2

  8. FIELD EMISSION FROM BORON-DOPING POLYCRYSTALLINE DIAMOND FILMS ON SILICON

    E-Print Network [OSTI]

    FIELD EMISSION FROM BORON-DOPING POLYCRYSTALLINE DIAMOND FILMS ON SILICON J. A. N. Gonçalves, G. M material fail. The field emission current from boron-doped polycrystalline diamond films grown by hot Campos, SP, Brazi Abstract This work deals with the study and development of the boron-doped diamond

  9. Hafnium-doped tantalum oxide high-k gate dielectric films for future CMOS technology

    E-Print Network [OSTI]

    Lu, Jiang

    2007-04-25T23:59:59.000Z

    of the doped films were explained by their compositions and bond structures. The Hf-doped TaOx film is a potential high-k gate dielectric for future MOS transistors. A 5 Ã?Â? tantalum nitride (TaNx) interface layer has been inserted between the Hf-doped Ta...

  10. Active waveguide fabrication in erbium-doped oxyfluoride silicate glass using femtosecond pulses

    E-Print Network [OSTI]

    Active waveguide fabrication in erbium-doped oxyfluoride silicate glass using femtosecond pulses R September 2005 By directly writing waveguides inside bulk erbium-doped oxyfluoride silicate glass using-doped oxyfluoride silicate glass using femtosecond pulses.3 These glasses, also fabri- cated by us, have been shown

  11. Optical properties of doped polycarbonate layers A.B. Djurisic a,*, W.L. Guo a

    E-Print Network [OSTI]

    Optical properties of doped polycarbonate layers A.B. Djurisic a,*, W.L. Guo a , E.H. Li a , L Abstract Optical properties of polycarbonate layers doped with triphenylamine and chlorotricarbonyl diimine or to enhance photogeneration. Doping polycarbonate (PC) with triphenylamine is known to enhance hole transport

  12. Si/SiGe modulation-doped structures with thin buffer layers: Effect of substrate orientation

    E-Print Network [OSTI]

    Allen, Leslie H.

    Si/SiGe modulation-doped structures with thin buffer layers: Effect of substrate orientation G. L and Nomarski microscopy. In n-type modulation-doped Si-SiGe structures, the band structure is type II where SiGe layer, generally on top of the strained Si, is intentionally doped leaving the adjacent Si layer

  13. Europium-doped Pyrochlores for Use as Thermographic Phosphors in Thermal Barrier Coatings

    E-Print Network [OSTI]

    Walker, D. Greg

    Europium-doped Pyrochlores for Use as Thermographic Phosphors in Thermal Barrier Coatings Saunak K different europium-doped pyrochlores as thermographic phosphors ­ La2Zr2O7:Eu, La2Hf2O7:Eu, Nd2Zr2O7:Eu, oxynitrates, and glycine · Samples doped at 4 mol % with europium which substitutes into the A3+ site

  14. Europium-Doped TiO2 Hollow Nanoshells: Two-Photon Imaging of Cell Binding

    E-Print Network [OSTI]

    Kummel, Andrew C.

    Europium-Doped TiO2 Hollow Nanoshells: Two-Photon Imaging of Cell Binding Sergio Sandoval,,,§ Jian method to fabricate luminescent monodisperse 200 nm europium-doped hollow TiO2 nanoshell (NS) particles-functionalized polystyrene beads were used as templates, and the porous walls of europium-doped titania nanoshells were

  15. Doping-assisted defect control in compound semiconductors

    SciTech Connect (OSTI)

    Specht, Petra; Weber, Eicke R.; Weatherford, Todd Russell

    2006-07-11T23:59:59.000Z

    The present invention relates to the production of thin film epilayers of III–V and other compounds with acceptor doping wherein the acceptor thermally stabilizes the epilayer, stabilize the naturally incorporated native defect population and therewith maintain the epilayer's beneficial properties upon annealing among other advantageous effects. In particular, balanced doping in which the acceptor concentration is similar to (but does not exceed) the antisite defects in the as-grown material is shown to be particularly advantageous in providing thermal stability, high resistivity and ultrashort trapping times. In particular, MBE growth of LT-GaAs epilayers with balanced Be doping is described in detail. The growth conditions greatly enhance the materials reproducibility (that is, the yield in processed devices). Such growth techniques can be transferred to other III–V materials if the growth conditions are accurately reproduced. Materials produced herein also demonstrate advantages in reproducibility, reliability and radiation hardening.

  16. Stable doping of carbon nanotubes via molecular self assembly

    SciTech Connect (OSTI)

    Lee, B.; Chen, Y.; Podzorov, V., E-mail: podzorov@physics.rutgers.edu [Department of Physics and Institute for Advanced Materials and Devices for Nanotechnology, Rutgers University, New Jersey 08854 (United States); Cook, A.; Zakhidov, A. [Department of Physics and NanoTech Institute, University of Texas at Dallas, Richardson, Texas 75083 (United States)

    2014-10-14T23:59:59.000Z

    We report a novel method for stable doping of carbon nanotubes (CNT) based on methods of molecular self assembly. A conformal growth of a self-assembled monolayer of fluoroalkyl trichloro-silane (FTS) at CNT surfaces results in a strong increase of the sheet conductivity of CNT electrodes by 60–300%, depending on the CNT chirality and composition. The charge carrier mobility of undoped partially aligned CNT films was independently estimated in a field-effect transistor geometry (~100 cm²V?¹s?¹). The hole density induced by the FTS monolayer in CNT sheets is estimated to be ~1.8 ×10¹?cm?². We also show that FTS doping of CNT anodes greatly improves the performance of organic solar cells. This large and stable doping effect, easily achieved in large-area samples, makes this approach very attractive for applications of CNTs in transparent and flexible electronics.

  17. Single-poly EEPROM cell with lightly doped MOS capacitors

    DOE Patents [OSTI]

    Riekels, James E. (New Hope, MN); Lucking, Thomas B. (Maple Grove, MN); Larsen, Bradley J. (Mound, MN); Gardner, Gary R. (Golden Valley, MN)

    2008-05-27T23:59:59.000Z

    An Electrically Erasable Programmable Read Only Memory (EEPROM) memory cell and a method of operation are disclosed for creating an EEPROM memory cell in a standard CMOS process. A single polysilicon layer is used in combination with lightly doped MOS capacitors. The lightly doped capacitors employed in the EEPROM memory cell can be asymmetrical in design. Asymmetrical capacitors reduce area. Further capacitance variation caused by inversion can also be reduced by using multiple control capacitors. In addition, the use of multiple tunneling capacitors provides the benefit of customized tunneling paths.

  18. Doping of carbon foams for use in energy storage devices

    DOE Patents [OSTI]

    Mayer, S.T.; Pekala, R.W.; Morrison, R.L.; Kaschmitter, J.L.

    1994-10-25T23:59:59.000Z

    A polymeric foam precursor, wetted with phosphoric acid, is pyrolyzed in an inert atmosphere to produce an open-cell doped carbon foam, which is utilized as a lithium intercalation anode in a secondary, organic electrolyte battery. Tests were conducted in a cell containing an organic electrolyte and using lithium metal counter and reference electrodes, with the anode located there between. Results after charge and discharge cycling, for a total of 6 cycles, indicated a substantial increase in the energy storage capability of the phosphorus doped carbon foam relative to the undoped carbon foam, when used as a rechargeable lithium ion battery. 3 figs.

  19. Doping of carbon foams for use in energy storage devices

    DOE Patents [OSTI]

    Mayer, Steven T. (San Leandro, CA); Pekala, Richard W. (Pleasant Hill, CA); Morrison, Robert L. (Modesto, CA); Kaschmitter, James L. (Pleasanton, CA)

    1994-01-01T23:59:59.000Z

    A polymeric foam precursor, wetted with phosphoric acid, is pyrolyzed in an inert atmosphere to produce an open-cell doped carbon foam, which is utilized as a lithium intercalation anode in a secondary, organic electrolyte battery. Tests were conducted in a cell containing an organic electrolyte and using lithium metal counter and reference electrodes, with the anode located therebetween. Results after charge and discharge cycling, for a total of 6 cycles, indicated a substantial increase in the energy storage capability of the phosphorus doped carbon foam relative to the undoped carbon foam, when used as a rechargeable lithium ion battery.

  20. Magnetic properties of Ga doped cobalt ferrite: Compton scattering study

    SciTech Connect (OSTI)

    Sharma, Arvind, E-mail: arvind.phd.swm@gmail.com; Mund, H. S.; Ahuja, B. L. [Department of Physics, University College of Science, M.L. Sukhadia University, Udaipur-313001 (India); Sahariya, Jagrati [Department of Physics, Manipal University, Jaipur-303007 (India); Itou, M.; Sakurai, Y. [Japan Synchrotron Radiation Research Institute, SPring8, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan)

    2014-04-24T23:59:59.000Z

    We present the spin momentum density of Ga doped CoFe{sub 2}O{sub 4} at 100 K using magnetic Compton scattering. The measurement has been performed using circularly polarized synchrotron radiations of 182.65 keV at SPring8, Japan. The experimental profile is decomposed into its constituent profile to determine the spin moment at individual sites. Co atom has the maximum contribution (about 58%) in the total spin moment of the doped CoFe{sub 2}O{sub 4}.

  1. Controlled Chemical Doping of Semiconductor Nanocrystals Using Redox Buffers

    SciTech Connect (OSTI)

    Engel, Jesse H.; Surendranath, Yogesh; Alivisatos, Paul

    2013-07-09T23:59:59.000Z

    Semiconductor nanocrystal solids are attractive materials for active layers in next-generation optoelectronic devices; however, their efficient implementation has been impeded by the lack of precise control over dopant concentrations. Herein we demonstrate a chemical strategy for the controlled doping of nanocrystal solids under equilibrium conditions. Exposing lead selenide nanocrystal thin films to solutions containing varying proportions of decamethylferrocene and decamethylferrocenium incrementally and reversibly increased the carrier concentration in the solid by 2 orders of magnitude from their native values. This application of redox buffers for controlled doping provides a new method for the precise control of the majority carrier concentration in porous semiconductor thin films.

  2. Theory of the spontaneous buckling of doped graphene

    E-Print Network [OSTI]

    Doron Gazit

    2009-03-11T23:59:59.000Z

    Graphene is a realization of an esoteric class of materials -- electronic crystalline membranes. We study the interplay between the free electrons and the two-dimensional crystal, and find that it induces a substantial effect on the elastic structure of the membrane. For the hole-doped membrane, in particular, we predict a spontaneous buckling. In addition, attenuation of elastic waves is expected, due to the effect of corrugations on the bulk modulus. These discoveries have a considerable magnitude in graphene, affecting both its mesoscopic structure, and its electrical resistivity, which has an inherent asymmetry between hole- and electron-doped graphene.

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

    E-Print Network [OSTI]

    Zeng, Li

    2007-01-01T23:59:59.000Z

    vapor deposition polycrystalline diamond ?lms. Diamonddoped (B- doped) polycrystalline diamond thin ?lms (MR?

  4. Scanning Tunneling Microscopy Study of Cr-doped GaN Surface Grown by RF Plasma Molecular Beam Epitaxy

    E-Print Network [OSTI]

    doped MOCVD grown GaN on sapphire substrate [2]. Park et al. performed the growth of Cr doped GaN singleScanning Tunneling Microscopy Study of Cr-doped GaN Surface Grown by RF Plasma Molecular Beam Orleans, New Orleans, LA 70148, USA Abstract: Cr doped GaN was grown by rf N-plasma molecular beam epitaxy

  5. Towards an Er-doped Si nanocrystal sensitized waveguide laser the thin line between gain and loss

    E-Print Network [OSTI]

    Polman, Albert

    somehow be eliminated from this scheme, the fabrication of low-cost Si based Er doped optical amplifiers1 Towards an Er-doped Si nanocrystal sensitized waveguide laser ­ the thin line between gain-doped Si nanocrystal co-doped SiO2, a composite material that can potentially be fabricated using a VLSI

  6. Photocatalytic activity of nitrogen doped rutile TiO{sub 2} nanoparticles under visible light irradiation

    SciTech Connect (OSTI)

    Yang Songwang [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Gao Lian [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China)], E-mail: liangaoc@online.sh.cn

    2008-07-01T23:59:59.000Z

    This work provides the design and synthesis of nitrogen doped rutile TiO{sub 2} nanoparticles working as efficient photocatalysts under visible light irradiation. Nitrogen doped rutile TiO{sub 2} nanoparticles are synthesized through the surface nitridation of rutile nanoparticles, which have been prepared in advance. The experimental results show that the nitrogen element is easily doped into the lattice of TiO{sub 2} nanoparticles and its doping amount increases with the decrease of nanocrystallite size. The photocatalytic activity of the nanoparticles under visible light irradiation is correlated not only with the amount of doped nitrogen element but also with the morphology and crystallinity of nanoparticles.

  7. Local control of magnetic damping in ferromagnetic/non-magnetic bilayers by interfacial intermixing induced by focused ion-beam irradiation

    SciTech Connect (OSTI)

    King, J. A.; Burn, D. M.; Sallabank, E. A.; Hindmarch, A. T.; Atkinson, D., E-mail: del.atkinson@durham.ac.uk, E-mail: abarman@bose.res.in [Department of Physics, Durham University, Durham DH1 3LE (United Kingdom); Ganguly, A.; Pal, S.; Barman, A., E-mail: del.atkinson@durham.ac.uk, E-mail: abarman@bose.res.in [Thematic Unit of Excellence on Nanodevice Technology and Department of Condensed Matter Physics and Material Sciences, S.N. Bose National Centre for Basic Sciences, Salt Lake, Kolkata 700 098 (India); Hase, T. P. A. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom)

    2014-06-16T23:59:59.000Z

    The influence of interfacial intermixing on the picosecond magnetization dynamics of ferromagnetic/non-magnetic thin-film bilayers was studied. Low-dose focused-ion-beam irradiation was used to induce intermixing across the interface between a 10?nm Ni{sub 81}Fe{sub 19} layer and a 2–3?nm capping layer of either Au or Cr. Time-resolved magneto-optical Kerr effect was used to study magnetization dynamics as a function of ion-beam dose. With an Au cap, the damping of the un-irradiated bilayer was comparable with native Ni{sub 81}Fe{sub 19} and increased with increasing ion dose. In contrast, for Ni{sub 81}Fe{sub 19}/Cr the damping was higher than that for native Ni{sub 81}Fe{sub 19}, but the damping decreased with increasing dose.

  8. RICH METHANE PREMIXED LAMINAR FLAMES DOPED BY LIGHT UNSATURATED HYDROCARBONS

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    RICH METHANE PREMIXED LAMINAR FLAMES DOPED BY LIGHT UNSATURATED HYDROCARBONS PART I: ALLENE developed in our laboratory for the reactions of C3-C4 unsaturated hydrocarbons. The main reaction pathways2007 #12;3 INTRODUCTION Soots and polyaromatic hydrocarbons (PAH), which are present in the exhaust gas

  9. Metal-doped semiconductor nanoparticles and methods of synthesis thereof

    DOE Patents [OSTI]

    Ren, Zhifeng (Newton, MA); Chen, Gang (Carlisle, MA); Poudel, Bed (West Newton, MA); Kumar, Shankar (Newton, MA); Wang, Wenzhong (Beijing, CN); Dresselhaus, Mildred (Arlington, MA)

    2009-09-08T23:59:59.000Z

    The present invention generally relates to binary or higher order semiconductor nanoparticles doped with a metallic element, and thermoelectric compositions incorporating such nanoparticles. In one aspect, the present invention provides a thermoelectric composition comprising a plurality of nanoparticles each of which includes an alloy matrix formed of a Group IV element and Group VI element and a metallic dopant distributed within the matrix.

  10. Process for fabricating doped zinc oxide microsphere gel

    DOE Patents [OSTI]

    Arnold, W.D. Jr.; Bond, W.D.; Lauf, R.J.

    1991-11-05T23:59:59.000Z

    Disclosed are a new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel. 4 figures.

  11. Process for fabricating doped zinc oxide microsphere gel

    DOE Patents [OSTI]

    Arnold, Jr., Wesley D. (Oak Ridge, TN); Bond, Walter D. (Knoxville, TN); Lauf, Robert J. (Oak Ridge, TN)

    1991-01-01T23:59:59.000Z

    A new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel.

  12. Doped Carbon Nanotubes for Hydrogen Storage Ragaiy Zidan

    E-Print Network [OSTI]

    hydrogen storage system is expected to be simple to engineer and tremendously safer. Carbon nanotubesDoped Carbon Nanotubes for Hydrogen Storage Ragaiy Zidan Savannah River Technology Center Savannah-capacity hydrogen storage material. The final product should have favorable thermodynamics and kinetics

  13. High capacity nickel battery material doped with alkali metal cations

    DOE Patents [OSTI]

    Jackovitz, John F. (Monroeville, PA); Pantier, Earl A. (Penn Hills, PA)

    1982-05-18T23:59:59.000Z

    A high capacity battery material is made, consisting essentially of hydrated Ni(II) hydroxide, and about 5 wt. % to about 40 wt. % of Ni(IV) hydrated oxide interlayer doped with alkali metal cations selected from potassium, sodium and lithium cations.

  14. Doped tantalum oxide high K dielectric thin films

    E-Print Network [OSTI]

    Donnelly, Joseph Patrick

    2000-01-01T23:59:59.000Z

    , it was doped with varying amounts of titanium oxide, aluminum oxide and silicon dioxide. The composite oxide films were deposited by reactive radio frequency (RF) cc-sputtering of two targets in a variety of oxygen and argon feed gas mixtures. The targets used...

  15. Fabrication and Characterization of Titanium-doped Hydroxyapatite Thin Films

    E-Print Network [OSTI]

    Desai, Amit Y

    . Thin films of titanium-doped hydroxyapatite (HA-Ti) have been deposited onto silicon substrates at three different compositions. With direct current (dc) power to the Ti target of 5, 10, and 15W films with compositions of 0.7, 1.7 and 2.0 at.% titanium...

  16. New Faces of GaN: Growth, Doping and Devices

    E-Print Network [OSTI]

    California at Santa Barbara, University of

    New Faces of GaN: Growth, Doping and Devices James S. Speck Materials Department University of California Santa Barbara, CA LEO of a-GaN from circular opening Engineering Insights 2006 #12;#12;Personnel. Wraback (ARL) $$$ JST ­ ERATO UCSB SSLDC AFOSR ONR #12;Reversed direction of polarization Bulk GaN

  17. Tunable, rare earth-doped solid state lasers

    DOE Patents [OSTI]

    Emmett, John L. (Pleasanton, CA); Jacobs, Ralph R. (Livermore, CA); Krupke, William F. (Pleasanton, CA); Weber, Marvin J. (Danville, CA)

    1980-01-01T23:59:59.000Z

    Laser apparatus comprising combinations of an excimer pump laser and a rare earth-doped solid matrix, utilizing the 5d-4f radiative transition in a rare earth ion to produce visible and ultra-violet laser radiation with high overall efficiency in selected cases and relatively long radiative lifetimes.

  18. Effects of hydrochloric acid treatment of TiO{sub 2} nanoparticles/nanofibers bilayer film on the photovoltaic properties of dye-sensitized solar cells

    SciTech Connect (OSTI)

    Song, Lixin; Du, Pingfan; Shao, Xiaoli; Cao, Houbao; Hui, Quan [Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Xiong, Jie, E-mail: jxiong@zstu.edu.cn [Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018 (China)

    2013-03-15T23:59:59.000Z

    Highlights: ? The TiO{sub 2} nanoparticles/TiO{sub 2} nanofibers bilayer film was fabricated for DSSC. ? The effects of HCl treated TiO{sub 2} on the performance of DSSC were investigated. ? The potential methods of improving conversion efficiency are suggested. - Abstract: The TiO{sub 2} nanoparticles/nanofibers bilayer film has been fabricated via spin coating and electrospinning followed by calcination. The TiO{sub 2} bilayer film with thickness of about 6.0 ?m is composed of anatase TiO{sub 2} phase. Dye-sensitized solar cells (DSSC) were assembled by hydrochloric acid (HCl) treated TiO{sub 2} film. The results of the photocurrent action spectra, electrochemical impedance spectroscopy (EIS), and I–V curves showed that each photovoltaic parameter of DSSC increased with the concentration of HCl increasing, and reached a maximum value and afterwards decreased. The maximum incident monochromatic photo-to-electron conversion efficiency (at 350 nm) and maximum overall conversion efficiency (?) of 0.05 M HCl treated TiO{sub 2} based DSSC were enhanced to 48.0% and 4.75%, which were respectively increased by 14% and 6.3% than those of DSSC based on untreated TiO{sub 2} film.

  19. Monte Carlo Study of Strongly-Interacting Degenerate Fermions: a Model for Voltage-Biased Bilayer Graphene

    E-Print Network [OSTI]

    Wes Armour; Simon Hands; Costas Strouthos

    2013-02-07T23:59:59.000Z

    We formulate a model of N_f=4 flavors of relativistic fermion in 2+1d in the presence of a chemical potential mu coupled to two flavor doublets with opposite sign, akin to isopsin chemical potential in QCD. This is argued to be an effective theory for low energy electronic excitations in bilayer graphene, in which an applied voltage between the layers ensures equal populations of particles on one layer and holes on the other. The model is then reformulated on a spacetime lattice using staggered fermions, and in the absence of a sign problem, simulated using an orthodox hybrid Monte Carlo algorithm. With the coupling strength chosen to be close to a quantum critical point believed to exist for N_f

  20. Detection and quantification of inverse spin Hall effect from spin pumping in permalloy/normal metal bilayers.

    SciTech Connect (OSTI)

    Mosendz, O.; Vlaminck, V.; Pearson, J. E.; Fradin, F. Y.; Bauer, G. E. W.; Bader, S. D.; Hoffmann, A.; Delft Univ. of Technology

    2010-12-01T23:59:59.000Z

    Spin pumping is a mechanism that generates spin currents from ferromagnetic resonance over macroscopic interfacial areas, thereby enabling sensitive detection of the inverse spin Hall effect that transforms spin into charge currents in nonmagnetic conductors. Here we study the spin-pumping-induced voltages due to the inverse spin Hall effect in permalloy/normal metal bilayers integrated into coplanar waveguides for different normal metals and as a function of angle of the applied magnetic field direction, as well as microwave frequency and power. We find good agreement between experimental data and a theoretical model that includes contributions from anisotropic magnetoresistance and inverse spin Hall effect. The analysis provides consistent results over a wide range of experimental conditions as long as the precise magnetization trajectory is taken into account. The spin Hall angles for Pt, Pd, Au, and Mo were determined with high precision to be 0.013 {+-} 0.002, 0.0064 {+-} 0.001, 0.0035 {+-} 0.0003, and -0.0005 {+-} 0.0001, respectively.

  1. Nanosecond molecular relaxations in lipid bilayers studied by high energy resolution neutron scattering and in-situ diffraction

    E-Print Network [OSTI]

    Maikel C. Rheinstädter; Tilo Seydel; Tim Salditt

    2006-07-20T23:59:59.000Z

    We report a high energy-resolution neutron backscattering study to investigate slow motions on nanosecond time scales in highly oriented solid supported phospholipid bilayers of the model system DMPC -d54 (deuterated 1,2-dimyristoyl-sn-glycero-3-phoshatidylcholine), hydrated with heavy water. Wave vector resolved quasi-elastic neutron scattering (QENS) is used to determine relaxation times $\\tau$, which can be associated with different molecular components, i.e., the lipid acyl chains and the interstitial water molecules in the different phases of the model membrane system. The inelastic data are complemented both by energy resolved and energy integrated in-situ diffraction. From a combined analysis of the inelastic data in the energy and time domain, the respective character of the relaxation, i.e., the exponent of the exponential decay is also determined. From this analysis we quantify two relaxation processes. We associate the fast relaxation with translational diffusion of lipid and water molecules while the slow process likely stems from collective dynamics.

  2. Polarization doping and the efficiency of III-nitride optoelectronic devices

    SciTech Connect (OSTI)

    Kivisaari, Pyry; Oksanen, Jani; Tulkki, Jukka [Department of Biomedical Engineering and Computational Science, Aalto University, P.O. Box 12200, FI-00076 Aalto (Finland)] [Department of Biomedical Engineering and Computational Science, Aalto University, P.O. Box 12200, FI-00076 Aalto (Finland)

    2013-11-18T23:59:59.000Z

    The intrinsic polarization is generally considered a nuisance in III-nitride devices, but recent studies have shown that it can be used to enhance p- and n-type conductivity and even to replace impurity doping. We show by numerical simulations that polarization-doped light-emitting diode (LED) structures have a significant performance advantage over conventional impurity-doped LED structures. Our results indicate that polarization doping decreases electric fields inside the active region and potential barriers in the depletion region, as well as the magnitude of the quantum-confined Stark effect. The simulations also predict at least an order of magnitude increase in the current density corresponding to the maximum efficiency (i.e., smaller droop) as compared to impurity-doped structures. The obtained high doping concentrations could also enable, e.g., fabrication of III-N resonant tunneling diodes and improved ohmic contacts.

  3. Control of work function of graphene by plasma assisted nitrogen doping

    SciTech Connect (OSTI)

    Akada, Keishi; Terasawa, Tomo-o; Imamura, Gaku; Obata, Seiji; Saiki, Koichiro, E-mail: saiki@k.u-tokyo.ac.jp [Department of Complexity Science and Engineering, The University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba 277-8561 (Japan)

    2014-03-31T23:59:59.000Z

    Nitrogen doping is expected to provide several intriguing properties to graphene. Nitrogen plasma treatment to defect-free and defective highly oriented pyrolytic graphite (HOPG) samples causes doping of nitrogen atom into the graphene layer. Nitrogen atoms are initially doped at a graphitic site (inside the graphene) for the defect-free HOPG, while doping to a pyridinic or a pyrrolic site (edge of the graphene) is dominant for the defective HOPG. The work function of graphene correlates strongly with the site and amount of doped nitrogen. Nitrogen atoms doped at a graphitic site lower the work function, while nitrogen atoms at a pyridinic or a pyrrolic site increase the work function. Control of plasma treatment time and the amount of initial defect could change the work function of graphite from 4.3?eV to 5.4?eV, which would open a way to tailor the nature of graphene for various industrial applications.

  4. Process for fabricating device structures for real-time process control of silicon doping

    DOE Patents [OSTI]

    Weiner, Kurt H. (San Jose, CA)

    2001-01-01T23:59:59.000Z

    Silicon device structures designed to allow measurement of important doping process parameters immediately after the doping step has occurred. The test structures are processed through contact formation using standard semiconductor fabrication techniques. After the contacts have been formed, the structures are covered by an oxide layer and an aluminum layer. The aluminum layer is then patterned to expose the contact pads and selected regions of the silicon to be doped. Doping is then performed, and the whole structure is annealed with a pulsed excimer laser. But laser annealing, unlike standard annealing techniques, does not effect the aluminum contacts because the laser light is reflected by the aluminum. Once the annealing process is complete, the structures can be probed, using standard techniques, to ascertain data about the doping step. Analysis of the data can be used to determine probable yield reductions due to improper execution of the doping step and thus provide real-time feedback during integrated circuit fabrication.

  5. Electrical properties of nitrogen-doped float-zone silicon. Interim report, March-1984-March 1985

    SciTech Connect (OSTI)

    O'Leary, M.A.; Mitchel, W.C.

    1985-07-01T23:59:59.000Z

    Examination of nitrogen doped float zone silicon indicates that electrical properties are similiar to commerical Czochralski material. This material deserves further consideration for use in high power device and intrinsic infrared detector applications. Temperature-dependent Hall-effect measurements were made on as-received and neutron-transmutation-doped (NTD) sample of a nitrogen-doped float-zone silicon crystal to determine its electrical properties. Samples were studied in both as-received state and after various high-temperature anneals. Results were compared with commerical n-type Czochralski silicon and conventional neutron doped float zone silcion. Undoped, annealed samples of Si:N showed signs of inhomogeneities were not seen in lightly NTD's and annealed nitrogen-doped material, indicating that even light doping will mask effects of the proposed precipitation. No evidence was detected for any electrically active level that could be directly related to the nitrogen.

  6. Imaging doped silicon test structures using low energy electron microscopy.

    SciTech Connect (OSTI)

    Nakakura, Craig Yoshimi; Anderson, Meredith Lynn; Kellogg, Gary Lee

    2010-01-01T23:59:59.000Z

    This document is the final SAND Report for the LDRD Project 105877 - 'Novel Diagnostic for Advanced Measurements of Semiconductor Devices Exposed to Adverse Environments' - funded through the Nanoscience to Microsystems investment area. Along with the continuous decrease in the feature size of semiconductor device structures comes a growing need for inspection tools with high spatial resolution and high sample throughput. Ideally, such tools should be able to characterize both the surface morphology and local conductivity associated with the structures. The imaging capabilities and wide availability of scanning electron microscopes (SEMs) make them an obvious choice for imaging device structures. Dopant contrast from pn junctions using secondary electrons in the SEM was first reported in 1967 and more recently starting in the mid-1990s. However, the serial acquisition process associated with scanning techniques places limits on the sample throughput. Significantly improved throughput is possible with the use of a parallel imaging scheme such as that found in photoelectron emission microscopy (PEEM) and low energy electron microscopy (LEEM). The application of PEEM and LEEM to device structures relies on contrast mechanisms that distinguish differences in dopant type and concentration. Interestingly, one of the first applications of PEEM was a study of the doping of semiconductors, which showed that the PEEM contrast was very sensitive to the doping level and that dopant concentrations as low as 10{sup 16} cm{sup -3} could be detected. More recent PEEM investigations of Schottky contacts were reported in the late 1990s by Giesen et al., followed by a series of papers in the early 2000s addressing doping contrast in PEEM by Ballarotto and co-workers and Frank and co-workers. In contrast to PEEM, comparatively little has been done to identify contrast mechanisms and assess the capabilities of LEEM for imaging semiconductor device strictures. The one exception is the work of Mankos et al., who evaluated the impact of high-throughput requirements on the LEEM designs and demonstrated new applications of imaging modes with a tilted electron beam. To assess its potential as a semiconductor device imaging tool and to identify contrast mechanisms, we used LEEM to investigate doped Si test structures. In section 2, Imaging Oxide-Covered Doped Si Structures Using LEEM, we show that the LEEM technique is able to provide reasonably high contrast images across lateral pn junctions. The observed contrast is attributed to a work function difference ({Delta}{phi}) between the p- and n-type regions. However, because the doped regions were buried under a thermal oxide ({approx}3.5 nm thick), e-beam charging during imaging prevented quantitative measurements of {Delta}{phi}. As part of this project, we also investigated a series of similar test structures in which the thermal oxide was removed by a chemical etch. With the oxide removed, we obtained intensity-versus-voltage (I-V) curves through the transition from mirror to LEEM mode and determined the relative positions of the vacuum cutoffs for the differently doped regions. Although the details are not discussed in this report, the relative position in voltage of the vacuum cutoffs are a direct measure of the work function difference ({Delta}{phi}) between the p- and n-doped regions.

  7. Ytterbium-doped borate fluoride laser crystals and lasers

    DOE Patents [OSTI]

    Schaffers, Kathleen I. (Pleasanton, CA); DeLoach, Laura D. (Manteca, CA); Payne, Stephen A. (Castro Valley, CA); Keszler, Douglas A. (Corvallis, OK)

    1997-01-01T23:59:59.000Z

    A new class of solid state laser crystals and lasers are formed from Yb-doped borate fluoride host crystals. The general formula for the host crystals is MM'(BO.sub.3)F, where M, M' are monovalent, divalent aria trivalent metal cations. A particular embodiment of the invention is Yb-doped BaCaBO.sub.3 F (Yb:BCBF). BCBF and some of the related derivative crystals are capable of nonlinear frequency conversion, whereby the fundamental of the laser is converted to a longer or shorter wavelength. In this way, these new crystals can simultaneously serve as self-frequency doubling crystals and laser materials within the laser resonator.

  8. Ytterbium-doped borate fluoride laser crystals and lasers

    DOE Patents [OSTI]

    Schaffers, K.I.; DeLoach, L.D.; Payne, S.A.; Keszler, D.A.

    1997-10-14T23:59:59.000Z

    A new class of solid state laser crystals and lasers are formed from Yb-doped borate fluoride host crystals. The general formula for the host crystals is MM{prime}(BO{sub 3})F, where M, M{prime} are monovalent, divalent aria trivalent metal cations. A particular embodiment of the invention is Yb-doped BaCaBO{sub 3}F (Yb:BCBF). BCBF and some of the related derivative crystals are capable of nonlinear frequency conversion, whereby the fundamental of the laser is converted to a longer or shorter wavelength. In this way, these new crystals can simultaneously serve as self-frequency doubling crystals and laser materials within the laser resonator. 6 figs.

  9. Direct visualization of atomically precise nitrogen-doped graphene nanoribbons

    SciTech Connect (OSTI)

    Zhang, Yi; Zhang, Yanfang; Li, Geng; Lu, Jianchen; Du, Shixuan, E-mail: sxdu@iphy.ac.cn, E-mail: feng@mpip-mainz.mpg.de; Gao, Hong-Jun [Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190 (China); Lin, Xiao [University of Chinese Academy of Sciences and Institute of Physics, Chinese Academy of Sciences, Beijing 100049 (China); Berger, Reinhard; Feng, Xinliang, E-mail: sxdu@iphy.ac.cn, E-mail: feng@mpip-mainz.mpg.de; Müllen, Klaus [Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz (Germany)

    2014-07-14T23:59:59.000Z

    We have fabricated atomically precise nitrogen-doped chevron-type graphene nanoribbons by using the on-surface synthesis technique combined with the nitrogen substitution of the precursors. Scanning tunneling microscopy and spectroscopy indicate that the well-defined nanoribbons tend to align with the neighbors side-by-side with a band gap of 1.02?eV, which is in good agreement with the density functional theory calculation result. The influence of the high precursor coverage on the quality of the nanoribbons is also studied. We find that graphene nanoribbons with sufficient aspect ratios can only be fabricated at sub-monolayer precursor coverage. This work provides a way to construct atomically precise nitrogen-doped graphene nanoribbons.

  10. OPTICAL AND DYNAMIC PROPERTIES OF UNDOPED AND DOPED SEMICONDUCTOR NANOSTRUCTURES

    SciTech Connect (OSTI)

    Grant, C D; Zhang, J Z

    2007-09-28T23:59:59.000Z

    This chapter provides an overview of some recent research activities on the study of optical and dynamic properties of semiconductor nanomaterials. The emphasis is on unique aspects of these properties in nanostructures as compared to bulk materials. Linear, including absorption and luminescence, and nonlinear optical as well as dynamic properties of semiconductor nanoparticles are discussed with focus on their dependence on particle size, shape, and surface characteristics. Both doped and undoped semiconductor nanomaterials are highlighted and contrasted to illustrate the use of doping to effectively alter and probe nanomaterial properties. Some emerging applications of optical nanomaterials are discussed towards the end of the chapter, including solar energy conversion, optical sensing of chemicals and biochemicals, solid state lighting, photocatalysis, and photoelectrochemistry.

  11. High gain photoconductive semiconductor switch having tailored doping profile zones

    DOE Patents [OSTI]

    Baca, Albert G. (Albuquerque, NM); Loubriel, Guillermo M. (Albuquerque, NM); Mar, Alan (Albuquerque, NM); Zutavern, Fred J (Albuquerque, NM); Hjalmarson, Harold P. (Albuquerque, NM); Allerman, Andrew A. (Albuquerque, NM); Zipperian, Thomas E. (Edgewood, NM); O'Malley, Martin W. (Edgewood, NM); Helgeson, Wesley D. (Albuquerque, NM); Denison, Gary J. (Sandia Park, NM); Brown, Darwin J. (Albuquerque, NM); Sullivan, Charles T. (Albuquerque, NM); Hou, Hong Q. (Albuquerque, NM)

    2001-01-01T23:59:59.000Z

    A photoconductive semiconductor switch with tailored doping profile zones beneath and extending laterally from the electrical contacts to the device. The zones are of sufficient depth and lateral extent to isolate the contacts from damage caused by the high current filaments that are created in the device when it is turned on. The zones may be formed by etching depressions into the substrate, then conducting epitaxial regrowth in the depressions with material of the desired doping profile. They may be formed by surface epitaxy. They may also be formed by deep diffusion processes. The zones act to reduce the energy density at the contacts by suppressing collective impact ionization and formation of filaments near the contact and by reducing current intensity at the contact through enhanced current spreading within the zones.

  12. Electrochemical hydrogen termination of boron-doped diamond

    SciTech Connect (OSTI)

    Hoffmann, Rene; Kriele, Armin; Obloh, Harald; Hees, Jakob; Wolfer, Marco; Smirnov, Waldemar; Yang Nianjun; Nebel, Christoph E. [Fraunhofer Institute for Applied Solid State Physics (IAF), Tullastrasse 72, Freiburg 79108 (Germany)

    2010-08-02T23:59:59.000Z

    Boron-doped diamond is a promising transducer material for numerous devices which are designed for contact with electrolytes. For optimized electron transfer the surface of diamond needs to be hydrogen terminated. Up to now H-termination of diamond is done by plasma chemical vapor deposition techniques. In this paper, we show that boron-doped diamond can be H-terminated electrochemically by applying negative voltages in acidic solutions. Electrochemical H-termination generates a clean surface with virtually no carbon-oxygen bonds (x-ray photoelectron spectroscopy), a reduced electron affinity (scanning electron microscopy), a highly hydrophobic surface (water contact angle), and a fast electron exchange with Fe(CN){sub 6}{sup -3/-4} (cyclic voltammetry).

  13. Method of fabricating optical waveguides by ion implantation doping

    DOE Patents [OSTI]

    Appleton, B.R.; Ashley, P.R.; Buchal, C.J.

    1987-03-24T23:59:59.000Z

    A method for fabricating high-quality optical waveguides in optical quality oxide crystals by ion implantation doping and controlled epitaxial recrystallization is provided. Masked LiNbO/sub 3/ crystals are implanted with high concentrations of Ti dopant at ion energies of about 360 keV while maintaining the crystal near liquid nitrogen temperature. Ion implantation doping produces an amorphous, Ti-rich nonequilibrium phase in the implanted region. Subsequent thermal annealing in a water-saturated oxygen atmosphere at up to 1000/degree/C produces solid-phase epitaxial regrowth onto the crystalline substrate. A high-quality crystalline layer results which incorporates the Ti into the crystal structure at much higher concentrations than is possible by standard diffusion techniques, and this implanted region has excellent optical waveguiding properties.

  14. Visible light photocatalytic activity in nitrogen-doped TiO{sub 2} nanobelts

    SciTech Connect (OSTI)

    De Nyago Tafen; Lewis, James P. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506 (United States); Wang Jin; Wu Nianqiang [Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, West Virginia 26506 (United States)

    2009-03-02T23:59:59.000Z

    We present a comprehensive experimental and theoretical study of the electronic properties and photocatalytic activity of nitrogen-doped anatase TiO{sub 2} nanobelts. UV-visible spectra show enhanced absorption in the visible light range for nitrogen-doped nanobelts compared to the pristine sample. The nitrogen-doped nanobelts exhibit improved photocatalytic activity compared to the pristine sample upon visible light irradiation. Furthermore, the incorporation of nitrogen introduces localized states in the band gap.

  15. Oxygen vacancies in N doped anatese TiO2: Experiment and first principles calculations

    SciTech Connect (OSTI)

    Rumaiz, A.; Woicik, J.C.; Cockayne, E.; Lin, H.Y.; Hassnain, J.; Shah, S.I.

    2009-12-31T23:59:59.000Z

    We have determined the electronic and atomic structure of N doped TiO{sub 2} using a combination of hard x-ray photoelectron spectroscopy and first-principles density functional theory calculations. Our results reveal that N doping of TiO{sub 2} leads to the formation of oxygen vacancies and the combination of both N impurity and oxygen vacancies accounts for the observed visible light catalytic behavior of N doped TiO{sub 2}.

  16. Synthesis of mesoporous NiO doped TiO{sub 2} submicrosphere via spray hydrolysis

    SciTech Connect (OSTI)

    Bahadur, J.; Sen, D.; Prakash, J.; Singh, Ripandeep; Paul, B.; Mazumder, S.; Sathiyamoorthy, D. [Solid State Physics Division Bhabha Atomic Research Centre, Mumbai, 400085, India (India); Powder Metallurgy Division Bhabha Atomic Research Centre, Mumbai, 400085 (India); Solid State Physics, Division Bhabha Atomic Research Centre, Mumbai, 400085 (India); Materials Processing Division Bhabha Atomic Research Centre, Mumbai, 400085 (India); Solid State Physics Division Bhabha Atomic Research Centre, Mumbai, 400085 (India); Powder Metallurgy Division Bhabha Atomic Research Centre, Mumbai, 400085 (India)

    2012-06-05T23:59:59.000Z

    NiO doped TiO{sub 2} submicrosphere have been prepared via spray hydrolysis. The doping concentration has been varied form 2 wt% to 15 wt%. Morphology of the submicrospheres has been investigated using small-angle neutron scattering and scanning electron microscopy. Elemental analysis has been carried out by energy dispersive X-ray analysis which confirms the doping concentrations. The mesopores in submicrospheres possess cylindrical morphology.

  17. Method for measuring the drift mobility in doped semiconductors

    DOE Patents [OSTI]

    Crandall, R.S.

    1982-03-09T23:59:59.000Z

    A method for measuring the drift mobility of majority carriers in semiconductors consists of measuring the current transient in a Schottky-barrier device following the termination of a forward bias pulse. An example is given using an amorphous silicon hydrogenated material doped with 0.2% phosphorus. The method is particularly useful with material in which the dielectric relaxation time is shorter than the carrier transit time. It is particularly useful in material useful in solar cells. 10 figs.

  18. Self-doped microphase separated block copolymer electrolyte

    DOE Patents [OSTI]

    Mayes, Anne M. (Waltham, MA); Sadoway, Donald R. (Waltham, MA); Banerjee, Pallab (Boston, MA); Soo, Philip (Cambridge, MA); Huang, Biying (Cambridge, MA)

    2002-01-01T23:59:59.000Z

    A polymer electrolyte includes a self-doped microphase separated block copolymer including at least one ionically conductive block and at least one second block that is immiscible in the ionically conductive block, an anion immobilized on the polymer electrolyte and a cationic species. The ionically conductive block provides a continuous ionically conductive pathway through the electrolyte. The electrolyte may be used as an electrolyte in an electrochemical cell.

  19. Method for measuring the drift mobility in doped semiconductors

    DOE Patents [OSTI]

    Crandall, Richard S. (Princeton, NJ)

    1982-01-01T23:59:59.000Z

    A method for measuring the drift mobility of majority carriers in semiconductors consists of measuring the current transient in a Schottky-barrier device following the termination of a forward bias pulse. An example is given using an amorphous silicon hydrogenated material doped with 0.2% phosphorous. The method is particularly useful with material in which the dielectric relaxation time is shorter than the carrier transit time. It is particularly useful in material useful in solar cells.

  20. Non-aqueous solution preparation of doped and undoped lixmnyoz

    DOE Patents [OSTI]

    Boyle, Timothy J. (5801 Eubank, N.E., Apt. #97, Albuquerque, NM 87111); Voigt, James A. (187 Aaramar La., Corrales, NM 87048)

    1997-01-01T23:59:59.000Z

    A method for generation of phase-pure doped and undoped Li.sub.x Mn.sub.y O.sub.z precursors. The method of this invention uses organic solutions instead of aqueous solutions or nonsolution ball milling of dry powders to produce phase-pure precursors. These precursors can be used as cathodes for lithium-polymer electrolyte batteries. Dopants may be homogeneously incorporated to alter the characteristics of the powder.

  1. Oxidation of Al doped Au clusters: A first principles study

    SciTech Connect (OSTI)

    Rajesh, Chinagandham [RMC, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Majumder, Chiranjib [Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

    2009-06-21T23:59:59.000Z

    Using first principles method we report the oxidation of Al doped Au clusters. This work is divided into two parts: (i) the equilibrium structures and stability of Al doped Au{sub n-1} clusters (n=2-7,21) and (ii) the interaction of O{sub 2} with stable clusters. The calculations are performed using the plane wave pseudopotential approach under the density functional theory and generalized gradient approximation for the exchange and correlation functional. The optimized geometries of Au{sub n-1}Al clusters indicate that the substitution of Au by Al results an early onset of three-dimensional structures from tetramer onwards. This is different from the results of transition metal doped Au clusters, where the planar conformation of Au clusters retains up to heptamer. The stability of Au{sub n-1}Al clusters has been analyzed based on the binding energy, second difference in energy, and the energy gaps between the highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels. Based on the energetics, the Au{sub 3}Al and Au{sub 5}Al clusters are found to have extraordinary stability. The oxidation mechanism of Al doped Au clusters have been studied by the interaction of O{sub 2} with Al, Au, AuAl, Au{sub 3}Al, and Au{sub 20}Al clusters. It is found that the oxidation of Au{sub n-1}Al clusters undergoes via dissociative mechanism, albeit significant charge transfer from Al to Au. Moreover, the O{sub 2} molecule prefers to attach at the Al site rather than at the Au site.

  2. Theory of nitrogen doping of carbon nanoribbons: Edge effects

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

    Jiang, Jie; Turnbull, Joseph; Lu, Wenchang; Boguslawski, Piotr; Bernholc, J.

    2012-01-01T23:59:59.000Z

    Nitrogen doping of a carbon nanoribbon is profoundly affected by its one-dimensional character, symmetry, and interaction with edge states. Using state-of-the-art ab initio calculations, including hybrid exact-exchange density functional theory, we find that, for N-doped zigzag ribbons, the electronic properties are strongly dependent upon sublattice effects due to the non-equivalence of the two sublattices. For armchair ribbons, N-doping effects are different depending upon the ribbon family: for families 2 and 0, the N-induced levels are in the conduction band, while for family 1 the N levels are in the gap. In zigzag nanoribbons, nitrogen close to the edge is amore »deep center, while in armchair nanoribbons its behavior is close to an effective-mass-like donor with the ionization energy dependent on the value of the band gap. In chiral nanoribbons, we find strong dependence of the impurity level and formation energy upon the edge position of the dopant, while such site-specificity is not manifested in the magnitude of the magnetization.« less

  3. Theory of nitrogen doping of carbon nanoribbons: Edge effects

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

    Jiang, Jie [North Carolina State Univ., Raleigh, NC (United States) and Yale Univ, New Haven, CT (United States); Turnbull, Joseph [North Carolina State Univ., Raleigh, NC (United States); Lu, Wenchang [North Carolina State Univ., Raleigh, NC (United States) and Oak Ridge National Lab., TN (United States); Boguslawski, Piotr [North Carolina State Univ., Raleigh, NC (United States) and Institute of Physics, Warsaw, and Bydgoszcz (Poland); Bernholc, J. [North Carolina State Univ., Raleigh, NC (United States) and Oak Ridge National Lab., TN (United States)

    2012-01-05T23:59:59.000Z

    Nitrogen doping of a carbon nanoribbon is profoundly affected by its one-dimensional character, symmetry, and interaction with edge states. Using state-of-the-art ab initio calculations, including hybrid exact-exchange density functional theory, we find that, for N-doped zigzag ribbons, the electronic properties are strongly dependent upon sublattice effects due to the non-equivalence of the two sublattices. For armchair ribbons, N-doping effects are different depending upon the ribbon family: for families 2 and 0, the N-induced levels are in the conduction band, while for family 1 the N levels are in the gap. In zigzag nanoribbons, nitrogen close to the edge is a deep center, while in armchair nanoribbons its behavior is close to an effective-mass-like donor with the ionization energy dependent on the value of the band gap. In chiral nanoribbons, we find strong dependence of the impurity level and formation energy upon the edge position of the dopant, while such site-specificity is not manifested in the magnitude of the magnetization.

  4. Plasmons in inhomogeneously doped neutral and charged graphene nanodisks

    SciTech Connect (OSTI)

    Silveiro, Iván [ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels (Barcelona) (Spain); Javier García de Abajo, F., E-mail: javier.garciadeabajo@icfo.es [ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels (Barcelona) (Spain); ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys, 23, 08010 Barcelona (Spain)

    2014-03-31T23:59:59.000Z

    We study plasmons in graphene nanodisks including the effect of inhomogeneity in the distribution of the doping charge. Specifically, we discuss the following two configurations: charged disks containing a fixed amount of additional carriers, which are self-consistently distributed along the surface to produce a uniform DC potential; and neutral disks exposed to a neighboring external point charge. A suitable finite-element method is elaborated to compute the charge density associated with the plasmons in the electrostatic limit. For charged disks, we find dipolar plasmons similar to those of uniformly doped graphene structures, in which the plasmon induced charge piles up near the edges. In contrast, in neutral disks placed near an external point charge, plasmons are strongly localized away from the edges. Surprisingly, a single external electron is enough to trap plasmons. The disks also display axially symmetric dark-plasmons, which can be excited through external illumination by coupling them to a neighboring metallic element. Our results have practical relevance for graphene nanophotonics under inhomogeneous doping conditions.

  5. Ca2+-Doped CeBr3 Scintillating Materials

    SciTech Connect (OSTI)

    Guss, Paul [NSTec; Foster, Michael E. [SNL; Wong, Bryan M. [SNL; Doty, F. Patrick [SNL; Shah, Kanai [RMD; Squillante, Michael R. [RMD; Shirwadkar, Urmila [RMD; Hawrami, Rastgo [RMD; Tower, Josh [RMD; Yuan, Ding [NSTec

    2014-01-21T23:59:59.000Z

    Despite the outstanding scintillation performance characteristics of cerium tribromide (CeBr3) and cerium-activated lanthanum tribromide, their commercial availability and application are limited due to the difficulties of growing large, crack-free single crystals from these fragile materials. This investigation employed aliovalent doping to increase crystal strength while maintaining the optical properties of the crystal. One divalent dopant (Ca2+) was used as a dopant to strengthen CeBr3 without negatively impacting scintillation performance. Ingots containing nominal concentrations of 1.9% of the Ca2+ dopant were grown. Preliminary scintillation measurements are presented for this aliovalently doped scintillator. Ca2+-doped CeBr3 exhibited little or no change in the peak fluorescence emission for 371 nm optical excitation for CeBr3. The structural, electronic, and optical properties of CeBr3 crystals were studied using the density functional theory within the generalized gradient approximation. The calculated lattice parameters are in good agreement with the experimental data. The energy band structures and density of states were obtained. The optical properties of CeBr3, including the dielectric function, were calculated.

  6. Doping of germanium and silicon crystals with non-hydrogenic acceptors for far infrared lasers

    DOE Patents [OSTI]

    Haller, Eugene E. (Berkeley, CA); Brundermann, Erik (Berlin, DE)

    2000-01-01T23:59:59.000Z

    A method for doping semiconductors used for far infrared lasers with non-hydrogenic acceptors having binding energies larger than the energy of the laser photons. Doping of germanium or silicon crystals with beryllium, zinc or copper. A far infrared laser comprising germanium crystals doped with double or triple acceptor dopants permitting the doped laser to be tuned continuously from 1 to 4 terahertz and to operate in continuous mode. A method for operating semiconductor hole population inversion lasers with a closed cycle refrigerator.

  7. Bismuth-doped optical fibres: A new breakthrough in near-IR lasing media

    SciTech Connect (OSTI)

    Dianov, Evgenii M [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation)

    2012-09-30T23:59:59.000Z

    Recent results demonstrate that bismuth-doped optical fibres have considerable potential as near-IR active lasing media. This paper examines bismuth-doped fibres intended for the fabrication of fibre lasers and optical amplifiers and reviews recent results on the luminescence properties of various types of bismuth-doped fibres and the performance of bismuth-doped fibre lasers and optical amplifiers for the spectral range 1150 - 1550 nm. Problems are discussed that have yet to be solved in order to improve the efficiency of the bismuth lasers and optical amplifiers. (optical fibres, lasers and amplifiers. properties and applications)

  8. Method of manufacturing semiconductor having group II-group VI compounds doped with nitrogen

    DOE Patents [OSTI]

    Compaan, Alvin D.; Price, Kent J.; Ma, Xianda; Makhratchev, Konstantin

    2005-02-08T23:59:59.000Z

    A method of making a semiconductor comprises depositing a group II-group VI compound onto a substrate in the presence of nitrogen using sputtering to produce a nitrogen-doped semiconductor. This method can be used for making a photovoltaic cell using sputtering to apply a back contact layer of group II-group VI compound to a substrate in the presence of nitrogen, the back coating layer being doped with nitrogen. A semiconductor comprising a group II-group VI compound doped with nitrogen, and a photovoltaic cell comprising a substrate on which is deposited a layer of a group II-group VI compound doped with nitrogen, are also included.

  9. SU-8 doped and encapsulated n-type graphene nanomesh with high air stability

    SciTech Connect (OSTI)

    Al-Mumen, Haider [Department of Electrical and Computer Engineering, Michigan State University, East Lansing, Michigan 48824 (United States) [Department of Electrical and Computer Engineering, Michigan State University, East Lansing, Michigan 48824 (United States); Department of Electrical Engineering, University of Babylon, Babylon (Iraq); Dong, Lixin; Li, Wen, E-mail: wenli@egr.msu.edu [Department of Electrical and Computer Engineering, Michigan State University, East Lansing, Michigan 48824 (United States)] [Department of Electrical and Computer Engineering, Michigan State University, East Lansing, Michigan 48824 (United States)

    2013-12-02T23:59:59.000Z

    N-type doping of graphene with long-term chemical stability in air represents a significant challenge for practical application of graphene electronics. This paper reports a reversible doping method to achieve highly stable n-type graphene nanomeshes, in which the SU-8 photoresist simultaneously serves as an effective electron dopant and an excellent encapsulating layer. The chemically stable n-type characteristics of the SU-8 doped graphene were evaluated in air using their Raman spectra, electrical transport properties, and electronic band structures. The SU-8 doping does minimum damage to the hexagonal carbon lattice of graphene and is completely reversible by removing the uncrosslinked SU-8 resist.

  10. anti-doping agency criteria: Topics by E-print Network

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

    Health Biostatistics Seminars Biology and Medicine Websites Summary: and Statistics, McGill University The statistical setting of decision limits for anti-doping tests...

  11. Increasing the thermoelectric figure of merit of tetrahedrites by Co-doping with nickel and zinc

    E-Print Network [OSTI]

    Lu, X; Morelli, DT; Morelli, DT; Xia, Y; Ozolins, V

    2015-01-01T23:59:59.000Z

    by  Co-­? doping  with  Nickel  and  Zinc   Xu  Lu 1 ,  t 2g   states   of   nickel   indeed   lie   in   the  of   the   dopant  nickel  ions.  While  one  could  

  12. Growth study and photocatalytic properties of Co-doped tungsten oxide mesocrystals

    SciTech Connect (OSTI)

    Sun, Shibin [College of Logistics Engineering, Shanghai Maritime University, Shanghai 200135 (China) [College of Logistics Engineering, Shanghai Maritime University, Shanghai 200135 (China); College of Electromechanical Engineering, Qingdao University of Science and Technology, Qingdao 266061 (China); Chang, Xueting, E-mail: xuetingchang@yahoo.cn [College of Logistics Engineering, Shanghai Maritime University, Shanghai 200135 (China)] [College of Logistics Engineering, Shanghai Maritime University, Shanghai 200135 (China); Li, Zhenjiang [College of Electromechanical Engineering, Qingdao University of Science and Technology, Qingdao 266061 (China)] [College of Electromechanical Engineering, Qingdao University of Science and Technology, Qingdao 266061 (China)

    2012-11-15T23:59:59.000Z

    Cobalt-doped tungsten oxide mesocrystals with different morphologies have been successfully generated using a solvothermal method with tungsten hexachloride and cobalt chloride salts as precursors. The resulting mesocrystals were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, Brunauer-Emmet-Teller analysis of nitrogen sorptometer, and UV-vis diffuse reflectance spectroscopy. The photocatalytic properties of the cobalt-doped tungsten oxide mesocrystals were evaluated on the basis of their ability to degrade methyl orange in an aqueous solution under simulated sunlight irradiation. Results showed that the cobalt doping had obvious effect on the morphologies of the final products, and lenticular and blocky cobalt-doped tungsten oxide mesocrystals could be obtained with 1.0 wt.% and 2.0 wt.% cobalt doping, respectively. The cobalt-doped tungsten oxides exhibited superior photocatalytic activities to that of the undoped tungsten oxide. - Graphical abstract: Schematic illustrations of the growth of the bundled nanowires, lenticular mesocrystals, and blocky mesocrystals. Highlights: Black-Right-Pointing-Pointer Co-doped W{sub 18}O{sub 49} mesocrystals were synthesized using a solvothermal method. Black-Right-Pointing-Pointer The Co doping has obvious effect on the morphology of the final mesocrystals. Black-Right-Pointing-Pointer The Co-doped W{sub 18}O{sub 49} exhibited superior photocatalytic activity to the undoped W{sub 18}O{sub 49}.

  13. Doping optimization of polypyrrole with toluenesulfonic acid using Box-Behnken design

    SciTech Connect (OSTI)

    Syed Draman, Sarifah Fauziah; Daik, Rusli [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); El-Sheikh, Said M. [Nanostructured Materials and Nanotechnology Division, Central Metallurgical Research and Development Institute,11421 Cairo (Egypt); Latif, Famiza Abdul [Faculty of Applied Sciences, Universiti Teknologi MARA Malaysia 40450 Shah Alam, Selangor (Malaysia)

    2013-11-27T23:59:59.000Z

    A three-level Box-Behnken design was employed in doping optimization of polypyrrole with toluenesulfonic acid (TSA-doped PPy). The material was synthesized via chemical oxidative polymerization using pyrrole, toluenesulfonic acid (TSA) and ammonium persulfate (APS) as monomer, dopant and oxidant, respectively. The critical factors selected for this study were concentration of dopant, molar ratio between dopant to monomer (pyrrole) and concentration of oxidant. Obtaining adequate doping level of TSA-doped PPy is crucial because it affects the charge carriers for doped PPy and usually be responsible for electronic mobility along polymeric chain. Furthermore, the doping level also affects other properties such as electrical and thermal conductivity. Doping level was calculated using elemental analysis. SEM images shows that the prepared TSA-doped PPy particles are spherical in shape with the diameters of about. The range of nanoparticles size is around 80-100 nm. The statistical analysis based on a Box–Behnken design showed that 0.01 mol of TSA, 1:1 mole ratio TSA to pyrrole and 0.25 M APS were the optimum conditions for sufficient doping level.

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

    E-Print Network [OSTI]

    Tao, Jonathan Huai-Tse

    2010-01-01T23:59:59.000Z

    Gallium Nitride Doped With Europium," J. Appl. Phys. , 95Electroluminescence of Europium-doped Gallium Oxide ThinLuminescence Properties of Europium– terbium Double

  15. The effect of interface oxygen content on magnetoelectric effect of epitaxial La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/BaTiO{sub 3} bilayer

    SciTech Connect (OSTI)

    Tingxian, Li, E-mail: wxlltx@126.com [College of Physics and Electrical Engineering, Anyang Normal University, Anyang 455002 (China); Kuoshe, Li [National Engineering Research Central for Rare Earth Materials, General Research Institute for Nonferrous Metals, The Grirem Advanced materials Co. Ltd., Beijing 100088 (China)

    2014-01-28T23:59:59.000Z

    The epitaxial La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/BaTiO{sub 3} (LSMO/BTO) bilayer films are grown on (001) oriented LaAlO{sub 3} substrate by pulsed laser deposition technique. The oxygen-rich interface is obtained through in-situ annealing process in oxygen, and the oxygen-deficient interface is obtained without the annealing process. The results show that the ferromagnetic properties of the LSMO film and the magnetoelectric effect (ME) of the bilayer films strongly correlate to the oxygen content at the interface of LSMO/BTO. The saturated magnetization and the ME voltage coefficient of the oxygen-rich bilayer film are higher than that of oxygen-deficient one. It suggests a more effective ME coupling at the LSMO/BTO interface, which are generated through not only the interface strain but also the spin polarized carriers.

  16. Electrically actuatable doped polymer flakes and electrically addressable optical devices using suspensions of doped polymer flakes in a fluid host

    DOE Patents [OSTI]

    Trajkovska-Petkoska, Anka; Jacobs, Stephen D.; Marshall, Kenneth L.; Kosc, Tanya Z.

    2010-05-11T23:59:59.000Z

    Doped electrically actuatable (electrically addressable or switchable) polymer flakes have enhanced and controllable electric field induced motion by virtue of doping a polymer material that functions as the base flake matrix with either a distribution of insoluble dopant particles or a dopant material that is completely soluble in the base flake matrix. The base flake matrix may be a polymer liquid crystal material, and the dopants generally have higher dielectric permittivity and/or conductivity than the electrically actuatable polymer base flake matrix. The dopant distribution within the base flake matrix may be either homogeneous or non-homogeneous. In the latter case, the non-homogeneous distribution of dopant provides a dielectric permittivity and/or conductivity gradient within the body of the flakes. The dopant can also be a carbon-containing material (either soluble or insoluble in the base flake matrix) that absorbs light so as to reduce the unpolarized scattered light component reflected from the flakes, thereby enhancing the effective intensity of circularly polarized light reflected from the flakes when the flakes are oriented into a light reflecting state. Electro-optic devices contain these doped flakes suspended in a host fluid can be addressed with an applied electric field, thus controlling the orientation of the flakes between a bright reflecting state and a non-reflecting dark state.

  17. Excellent Passivation and Low Reflectivity Al2O3/TiO2 Bilayer Coatings for n-Wafer Silicon Solar Cells: Preprint

    SciTech Connect (OSTI)

    Lee, B. G.; Skarp, J.; Malinen, V.; Li, S.; Choi, S.; Branz, H. M.

    2012-06-01T23:59:59.000Z

    A bilayer coating of Al2O3 and TiO2 is used to simultaneously achieve excellent passivation and low reflectivity on p-type silicon. This coating is targeted for achieving high efficiency n-wafer Si solar cells, where both passivation and anti-reflection (AR) are needed at the front-side p-type emitter. It could also be valuable for front-side passivation and AR of rear-emitter and interdigitated back contact p-wafer cells. We achieve high minority carrier lifetimes {approx}1 ms, as well as a nearly 2% decrease in absolute reflectivity, as compared to a standard silicon nitride AR coating.

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

    E-Print Network [OSTI]

    Zeng, Li

    2007-01-01T23:59:59.000Z

    various transition or rare-earth metals provide a rich ?eldTransition Metal (Mn) and Rare Earth (Gd) Doped AmorphousTransition Metal (Mn) and Rare Earth (Gd) Doped Amorphous

  19. Influence of damping constant on inverse spin hall voltage of La{sub 0.7}Sr{sub 0.3}MnO{sub 3}(x)/platinum bilayers

    SciTech Connect (OSTI)

    Luo, G. Y. [Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan (China); Department of Physics, National Taiwan University, Taipei 10617, Taiwan (China); Chang, C. R. [Department of Physics, National Taiwan University, Taipei 10617, Taiwan (China); Lin, J. G., E-mail: jglin@ntu.edu.tw [Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan (China)

    2014-05-07T23:59:59.000Z

    Pure spin transport via spin pumping in the condition of ferromagnetic resonance can be transformed to charge current in the ferromagnetic/paramagnetic bilayer systems, based on inverse spin Hall effect (ISHE). Here, we explore La{sub 0.7}Sr{sub 0.3}MnO(x)/Pt(5.5?nm) [x?=?10 to 65 nm] bilayers to investigate the influence of damping constant on spin pumping efficiency. The results show that the ISHE voltage depend on the damping constant of magnetic moment, suggesting that the precession energy tansferred to lattice/electron of normal metal is a key parameter to control the magnitude of spin current.

  20. Effect of doping on electronic states in B-doped polycrystalline CVD diamond films This article has been downloaded from IOPscience. Please scroll down to see the full text article.

    E-Print Network [OSTI]

    Bristol, University of

    Effect of doping on electronic states in B-doped polycrystalline CVD diamond films This article has-doped polycrystalline CVD diamond films O S Elsherif1,4, K D Vernon-Parry1, J H Evans-Freeman2 and P W May3 1 Materials the effect of boron (B) concentration on the electronic states in polycrystalline chemical vapour deposition

  1. MetalBosonic InsulatorSuperconductor Transition in Boron-Doped Granular Diamond Gufei Zhang,1,* Monika Zeleznik,2

    E-Print Network [OSTI]

    Bristol, University of

    . Second, the giant RðTÞ peak is observed in heavily boron-doped polycrystalline diamond thick filmsMetal­Bosonic Insulator­Superconductor Transition in Boron-Doped Granular Diamond Gufei Zhang,1 the onset of superconductivity in heavily boron-doped diamond. This anomalous RðTÞ peak in a 3D system

  2. Physical and magnetic properties of highly aluminum doped strontium ferrite nanoparticles prepared by auto-combustion route

    E-Print Network [OSTI]

    Liu, J. Ping

    Physical and magnetic properties of highly aluminum doped strontium ferrite nanoparticles prepared-Hexaferrite Al doped Sr-Ferrite High Coercivity Ferrite a b s t r a c t Highly Al3þ ion doped nanocrystalline Sr microscope show growth of needle shaped ferrites with high aspect ratio at Al3þ ion content exceeding xZ2. Al

  3. Experimental demonstration of efficient and selective population transfer and qubit distillation in a rare-earth-metal-ion-doped crystal

    E-Print Network [OSTI]

    Suter, Dieter

    in a rare-earth-metal-ion-doped crystal Lars Rippe, Mattias Nilsson, and Stefan Kröll Department of Physics on optical interactions in rare-earth- metal-ion-doped crystals. The optical transition lines of the rare-earth-metal out in preparation for two-qubit gate operations in the rare-earth-metal-ion-doped crystals

  4. Zero State Doped Turbo Equalizer Orhan GAZI, is with Electronics and Communication Engineering Department, Cankaya University, 06530,

    E-Print Network [OSTI]

    Yýlmaz, �zgür

    1 Zero State Doped Turbo Equalizer Orhan GAZI, is with Electronics and Communication Engineering. In this article we propose zero state doped turbo equalizers (ZSDTEs) which can be processed in parallel and have to the sliding window method. Index Terms-- Turbo Codes, Turbo Equalizer, Zero State Doped Turbo Equalizer. I

  5. Scanning Tunneling Microscopy Study of Cr-doped GaN Surface Grown by RF Plasma Molecular Beam Epitaxy

    E-Print Network [OSTI]

    on sapphire substrate [2]. Park et al. performed the growth of Cr doped GaN single crystal by sodium fluxScanning Tunneling Microscopy Study of Cr-doped GaN Surface Grown by RF Plasma Molecular Beam Orleans, New Orleans, LA 70148, USA Abstract: Cr doped GaN was grown by rf N-plasma molecular beam epitaxy

  6. Co-sputtered Aluminum Doped Zinc Oxide Thin Film as Transparent Anode for Organic Light-emitting Diodes

    E-Print Network [OSTI]

    Co-sputtered Aluminum Doped Zinc Oxide Thin Film as Transparent Anode for Organic Light and Technology, Clear Water Bay, Kowloon, Hong Kong, China ABSTRACT Aluminum doped zinc oxide (AZO that MTDATA matches better with AZO than CuPc, which served as hole injection layer. Keywords: Aluminum doped

  7. Bose Glass of Quasiparticles in Doped Quantum Magnet Gregory S. Boebinger, National High Magnetic Field Laboratory

    E-Print Network [OSTI]

    Weston, Ken

    Bose Glass of Quasiparticles in Doped Quantum Magnet Gregory S. Boebinger, National High Magnetic. This BEC can localize in the presence of disorder caused by Br- doping to form a Bose Glass. The BEC-Bose Glass (BEC-BG) transition can be carefully controlled by magnetic field, allowing us to sensitively

  8. Direction controllable linearly polarized laser from a dye-doped cholesteric liquid crystal

    E-Print Network [OSTI]

    Wu, Shin-Tson

    Direction controllable linearly polarized laser from a dye-doped cholesteric liquid crystal Ying demonstrate a direction controllable linearly polarized laser from a dye-doped cholesteric liquid crystal (CLC superposition of two orthogonal polarization states, the output laser light becomes linearly polarized and its

  9. Improving thermostability of CrO{sub 2} thin films by doping with Sn

    SciTech Connect (OSTI)

    Ding, Yi; Wang, Ziyu; Liu, Shuo; Shi, Jing; Yin, Di, E-mail: dyin@whu.edu.cn [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Yuan, Cheng; Lu, Zhihong, E-mail: zludavid@live.com [School of Materials and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081 (China); Xiong, Rui, E-mail: xiongrui@whu.edu.cn [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Wuhan 430062 (China)

    2014-09-01T23:59:59.000Z

    Chromium dioxide (CrO{sub 2}) is an ideal material for spin electronic devices since it has almost 100% spin polarization near Fermi level. However, it is thermally unstable and easily decomposes to Cr{sub 2}O{sub 3} even at room temperature. In this study, we try to improve the thermal stability of CrO{sub 2} thin films by doping with Sn whose oxide has the same structure as CrO{sub 2}. High quality epitaxial CrO{sub 2} and Sn-doped CrO{sub 2} films were grown on single crystalline TiO{sub 2} (100) substrates by chemical vapor deposition. Sn{sup 4+} ions were believed to be doped into CrO{sub 2} lattice and take the lattice positions of Cr{sup 4+}. The magnetic measurements show that Sn-doping leads to a decrease of magnetocrystalline anisotropy. The thermal stabilities of the films were evaluated by annealing the films at different temperatures. Sn-doped films can withstand a temperature up to 510?°C, significantly higher than what undoped films can do (lower than 435?°C), which suggests that Sn-doping indeed enhances the thermal stability of CrO{sub 2} films. Our study also indicates that Sn-doping may not change the essential half metallic properties of CrO{sub 2}. Therefore, Sn-doped CrO{sub 2} is expected to be very promising for applications in spintronic devices.

  10. Stability of Graphene doping with MoO_3 and I_2

    E-Print Network [OSTI]

    D’Arsié, Lorenzo; Esconjauregui, Santiago; Weatherup, Robert; Guo, Yuzheng; Bhardwaj, Sunil; Centeno, Alba; Zurutuza, Amaia; Cepek, Cinzia; Robertson, John

    2014-09-08T23:59:59.000Z

    We dope graphene by evaporation of MoO_3 or by solution-deposition of I_2 and assess the doping stability for its use as transparent electrodes. Electrical measurements show that both dopants increase the graphene sheet conductivity and find that Mo...

  11. Tuning nucleation density of metal island with charge doping of graphene Wenmei Ming and Feng Liua)

    E-Print Network [OSTI]

    Simons, Jack

    Tuning nucleation density of metal island with charge doping of graphene substrate Wenmei Ming calculation in Fe-deposition on graphene substrate as an example. It was found that hole-doping can noticeably-dimensional honeycomb crystal structure and exotic linearly dispersed electronic band struc- ture, graphene has

  12. Zirconium-doped tantalum oxide high-k gate dielectric films 

    E-Print Network [OSTI]

    Tewg, Jun-Yen

    2005-02-17T23:59:59.000Z

    A new high-k dielectric material, i.e., zirconium-doped tantalum oxide (Zr-doped TaOx), in the form of a sputter-deposited thin film with a thickness range of 5-100 nm, has been studied. Important applications of this new ...

  13. ccsd00002689, Dependence of the superconducting transition temperature on the doping level in

    E-Print Network [OSTI]

    reported for heavily boron-doped polycrystalline diamond pre- pared either as bulk [1] or thin #12;lm on the doping level in single crystalline diamond #12;lms E. Bustarret 1 , J. Ka#20;cmar#20;cik 2;3 , C Joseph Fourier, B.P.53, 38041 Grenoble Cedex 9, France (Dated: August 24, 2004) Homoepitaxial diamond

  14. Studies of n-type doping and surface modification of CVD diamond for use

    E-Print Network [OSTI]

    Bristol, University of

    strategy in chemical vapour deposition (CVD) of polycrystalline diamond films. Lithium nitride (Li3NStudies of n-type doping and surface modification of CVD diamond for use in thermionic applications-type dopants in diamond, the work has examined the use of Li-N codoping as a possible alternative doping

  15. Field emission properties of phosphorus doped microwave plasma chemical vapor deposition diamond films by ion implantation

    E-Print Network [OSTI]

    Lee, Jong Duk

    2002; published 5 February 2003 Phosphorus doped polycrystalline diamond films were grown using ion the electrical char- acteristics of diamond FEAs to lower the operating voltage. Polycrystalline diamond hasField emission properties of phosphorus doped microwave plasma chemical vapor deposition diamond

  16. Boron Doping of Microcrystalline and Nanocrystalline Diamond Films: Where is the Boron Paul William May1

    E-Print Network [OSTI]

    Bristol, University of

    is that polycrystalline boron-doped CVD diamond films possess grain boundaries containing a small-volume fraction of non-diamondBoron Doping of Microcrystalline and Nanocrystalline Diamond Films: Where is the Boron Going? Paul `cauliflower'-type nanocrystalline (c-NCD) CVD diamond films vary as a function of B content. The conductivity

  17. Spatially-correlated microstructure and superconductivity in polycrystalline Boron-doped diamond

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Spatially-correlated microstructure and superconductivity in polycrystalline Boron-doped diamond F are performed below 100 mK on polycrystalline Boron-doped diamond films characterized by Transmission Electron and the superconducting proximity effect.8,9 Neverthe- less, recent studies of polycrystalline diamond films10,11 did

  18. Raman and conductivity studies of boron doped microcrystalline diamond, facetted nanocrystalline diamond

    E-Print Network [OSTI]

    Bristol, University of

    superconductivity at temperatures polycrystalline boron-doped CVD diamond filmsRaman and conductivity studies of boron doped microcrystalline diamond, facetted nanocrystalline diamond and cauliflower diamond films P.W. May a,*, W.J. Ludlow a , M. Hannaway a , P.J. Heard b , J

  19. Co-doped mesoporous titania photocatalysts prepared from a peroxo-titanium complex solution

    SciTech Connect (OSTI)

    El Saliby, Ibrahim [Faculty of Engineering and Information Technology, University of Technology Sydney, NSW 2007 (Australia); Erdei, Laszlo [Faculty of Engineering and Surveying, University of Southern Queensland, Toowoomba, QLD 4350 (Australia); McDonagh, Andrew [Faculty of Science, University of Technology Sydney, NSW 2007 (Australia); Kim, Jong-Beom; Kim, Jong-Ho [The Research Institute for Catalysis, Chonnam National University, Gwangju 500-757 (Korea, Republic of); Photo and Environmental Technology Co. Ltd., Gwangju 500-460 (Korea, Republic of); Shon, Ho Kyong, E-mail: hokyong.shon-1@uts.edu.au [Faculty of Engineering and Information Technology, University of Technology Sydney, NSW 2007 (Australia)

    2014-01-01T23:59:59.000Z

    Graphical abstract: - Highlights: • Peroxotitanium complex for the synthesis of doped photocatalysts. • Fabrication of N doped and N/Ag co-doped photocatalysts. • Characterization of photocatalysts by SEM, XRD, BET, DRS and XPS. • Bench scale photocatalysis under simulated solar light using crystal violet pollutant. - Abstract: In this study, nitrogen doped and nitrogen/silver co-doped TiO{sub 2} photocatalsysts were fabricated using a sol–gel method at room temperature. The obtained gels were neutralized, washed with pure water, and calcined at 400 °C for 4 h. The photocatalysts were characterized by scanning and transmission electron microscopy, X-ray diffraction, diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, and BET specific surface area. The results showed that spherical particles with anatase structure were produced after annealing at 400 °C. N 1s (400 eV) and Ag 3d (367.3 eV) states indicated that nitrogen doping and silver co-doping were in the form of NO bonds and AgO, respectively. The photocatalytic activity of photocatalysts was investigated using a batch reactor system exposed to artificial solar irradiation. Both nitrogen and silver/nitrogen co-doped materials were effective in the photocatalytic degradation of hexamethyl pararosaniline chloride.

  20. Sonochemical synthesis and photocatalytic property of zinc oxide nanoparticles doped with magnesium(II)

    SciTech Connect (OSTI)

    Lu, Xianyong, E-mail: xylu@buaa.edu.cn [Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University, Beijing 100191 (China)] [Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University, Beijing 100191 (China); Liu, Zhaoyue; Zhu, Ying [Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University, Beijing 100191 (China)] [Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University, Beijing 100191 (China); Jiang, Lei, E-mail: jianglei@iccas.ac.cn [Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University, Beijing 100191 (China) [Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University, Beijing 100191 (China); Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

    2011-10-15T23:59:59.000Z

    Highlights: {yields} Mg-doped ZnO nanoparticles were synthesized by sonochemical strategy. {yields} Mg-doped ZnO nanoparticles present good photocatalytic properties. {yields} The change of band gap contributes to their high efficiency in photocatalyst. -- Abstract: Mg-doped ZnO nanoparticles were successfully synthesized by sonochemical method. The products were characterized by scan electron microscopy (SEM) and X-ray powder diffraction (XRD). SEM images revealed that ZnO doped with Mg(II) nanoparticles and ZnO nanoparticles synthesized by the same strategy all had spherical topography. XRD patterns showed that the doped nanoparticles had the same crystals structures as the pure ZnO nanoparticles. The Mg-doped ZnO nanoparticles had larger lattice volume than the un-doped nanoparticles. X-ray photoelectron spectroscopy (XPS) not only demonstrated the moral ratio of Mg and Zn element on the surface of nanoparticles, but their valence in nanoparticles as well. The Mg-doped ZnO nanoparticles presented good properties in photocatalyst compared with pure ZnO nanoparticles.

  1. Author's personal copy Prepration and photoluminescence properties of Ce doped lutetium silicate

    E-Print Network [OSTI]

    Cao, Guozhong

    Author's personal copy Prepration and photoluminescence properties of Ce doped lutetium silicate silicate Cerium Solegel Photoluminescence Lu2SiO5 a b s t r a c t Cerium doped lutetium silicate powders%). The synthesized lutetium silicate powders were investigated by X-ray diffraction (XRD), TG-DTA, SEM

  2. Zirconium-doped tantalum oxide high-k gate dielectric films

    E-Print Network [OSTI]

    Tewg, Jun-Yen

    2005-02-17T23:59:59.000Z

    A new high-k dielectric material, i.e., zirconium-doped tantalum oxide (Zr-doped TaOx), in the form of a sputter-deposited thin film with a thickness range of 5-100 nm, has been studied. Important applications of this new dielectric material include...

  3. The Electric and Optical Properties of Doped Small Molecular Organic Light-Emitting Devices

    SciTech Connect (OSTI)

    Kwang-Ohk Cheon

    2003-08-05T23:59:59.000Z

    Organic light-emitting devices (OLEDs) constitute a new and exciting emissive display technology. In general, the basic OLED structure consists of a stack of fluorescent organic layers sandwiched between a transparent conducting-anode and metallic cathode. When an appropriate bias is applied to the device, holes are injected from the anode and electrons from the cathode; some of the recombination events between the holes and electrons result in electroluminescence (EL). Until now, most of the efforts in developing OLEDs have focused on display applications, hence on devices within the visible range. However some organic devices have been developed for ultraviolet or infrared emission. Various aspects of the device physics of doped small molecular OLEDs were described and discussed. The doping layer thickness and concentration were varied systematically to study their effects on device performances, energy transfer, and turn-off dynamics. Low-energy-gap DCM2 guest molecules, in either {alpha}-NPD or DPVBi host layers, are optically efficient fluorophores but also generate deep carrier trap-sites. Since their traps reduce the carrier mobility, the current density decreases with increased doping concentration. At the same time, due to efficient energy transfer, the quantum efficiency of the devices is improved by light doping or thin doping thickness, in comparison with the undoped neat devices. However, heavy doping induces concentration quenching effects. Thus, the doping concentration and doping thickness may be optimized for best performance.

  4. Dopant location identification in Nd3+ -doped TiO2 nanoparticles

    E-Print Network [OSTI]

    Frenkel, Anatoly

    Dopant location identification in Nd3+ -doped TiO2 nanoparticles W. Li Department of Materials. The identification of dopant position and its local environ- ment are essential to explore the effect of doping. X and Technology, Gaithersburg, Maryland 20899, USA C. Ni Department of Materials Science and Engineering

  5. Effect of Sn and Ca doping on the corrosion of Pb anodes in lead acid batteries

    E-Print Network [OSTI]

    Popov, Branko N.

    Effect of Sn and Ca doping on the corrosion of Pb anodes in lead acid batteries Dragan Slavkova of lead anodes used in lead acid batteries. However, one drawback of these materials is their increased reserved. Keywords: Corrosion; Pb anodes; Lead acid batteries; Doping tin; Calcium 1. Introduction

  6. In situ doping control of the surface of high-temperature superconductors

    E-Print Network [OSTI]

    Michelson, David G.

    LETTERS In situ doping control of the surface of high-temperature superconductors M. A. HOSSAIN1.1038/nphys998 Central to the understanding of high-temperature superconductivity is the evolution of the electronic structure as doping alters the density of charge carriers in the CuO2 planes. Superconductivity

  7. Exploting iron doping in zirconia D. Sangalli, A. Lamperti, E. Cianci, R. Ciprian, M. Perego

    E-Print Network [OSTI]

    Marini, Andrea

    As/GaAs Ohno et al., PRL 68, 2664 (1992)Ohno et al., PRL 68, 2664 (1992) Ohno et al., APL 69 363 (1996)Ohno etPredicted very high Tc for TM doped ZrO2for TM doped ZrO2 Ostanin et al., PRL 98 016011 (2007)Ostanin et al., PRL

  8. Radiative heat transfer at nanoscale mediated by surface plasmons for highly doped Emmanuel Rousseau

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Radiative heat transfer at nanoscale mediated by surface plasmons for highly doped silicon the role of surface plasmons for nanoscale radiative heat transfer between doped silicon surfaces. We derive a new accurate and closed-form expression of the radiative near- field heat transfer. We also

  9. Electrical characterisation of defects in polycrystalline B-doped diamond films

    E-Print Network [OSTI]

    Bristol, University of

    applied to B-doped thin polycrystalline diamond films deposited on p+ -silicon by hot filament chemical]. Recently valuable information about defects in monocrystalline [3] and polycrystalline [7] diamond filmsElectrical characterisation of defects in polycrystalline B-doped diamond films O. S. Elsherif 1, a

  10. Fermi Level Control of Point Defects During Growth of Mg-Doped GaN

    E-Print Network [OSTI]

    Nabben, Reinhard

    Fermi Level Control of Point Defects During Growth of Mg-Doped GaN ZACHARY BRYAN,1,4 MARC HOFFMANN defects during metalorganic chem- ical vapor deposition (MOCVD) of Mg-doped GaN has been demonstrated of magnitude lower resistivity values compared with typical unan- nealed GaN:Mg samples. The PL spectra

  11. Study on europium doped hydroxyapatite nanoparticles by Fourier transform infrared spectroscopy and their antimicrobial properties

    E-Print Network [OSTI]

    Boyer, Edmond

    Study on europium doped hydroxyapatite nanoparticles by Fourier transform infrared spectroscopy were conducted on europium doped hydroxyapatite, Ca10-xEux(PO4)6(OH)2 nanocrystalline powders (Eu demonstrates that the antimicrobial activity of Eu:HAp nanoparticles is dependent on the europium concentration

  12. American Institute of Aeronautics and Astronautics Europium-doped Pyrochlores for Use as Thermographic

    E-Print Network [OSTI]

    Walker, D. Greg

    American Institute of Aeronautics and Astronautics 1 Europium-doped Pyrochlores for Use, Nashville, TN, 37235 Three europium-doped pyrochlores including La2Zr2O7:Eu, La2Hf2O7:Eu, and Nd2Zr2O7:Eu

  13. Europium and samarium doped calcium sulfide thin films grown by PLD S. Christoulakis a,c

    E-Print Network [OSTI]

    Europium and samarium doped calcium sulfide thin films grown by PLD S. Christoulakis a,c , M Suchea Abstract Europium and samarium doped calcium sulfide thin films (CaS:Eu,Sm) with different thickness were and crystallinity. In this work we present preliminary results related to the deposition of europium and samarium

  14. ELECTRON MICROPROBE AND PHOTOLUMINESCENCE ANALYSIS OF EUROPIUM-DOPED GALLIUM NITRIDE LIGHT EMITTERS

    E-Print Network [OSTI]

    Strathclyde, University of

    ELECTRON MICROPROBE AND PHOTOLUMINESCENCE ANALYSIS OF EUROPIUM-DOPED GALLIUM NITRIDE LIGHT EMITTERSN-on-sapphire epilayers implanted with Europium ions, producing characteristic red emission lines between 540 and 680 nm with energies largely independent of the host material. For example, doping with europium, erbium and thulium

  15. Atmospheric Oxygen Binding and Hole Doping in Deformed Graphene on a SiO2 Substrate

    E-Print Network [OSTI]

    Sunmin Ryu; Li Liu; Stephane Berciaud; Young-Jun Yu; Haitao Liu; Philip Kim; George W. Flynn; Louis E. Brus

    2010-11-13T23:59:59.000Z

    Using micro-Raman spectroscopy and scanning tunneling microscopy, we study the relationship between structural distortion and electrical hole doping of graphene on a silicon dioxide substrate. The observed upshift of the Raman G band represents charge doping and not compressive strain. Two independent factors control the doping: (1) the degree of graphene coupling to the substrate, and (2) exposure to oxygen and moisture. Thermal annealing induces a pronounced structural distortion due to close coupling to SiO2 and activates the ability of diatomic oxygen to accept charge from graphene. Gas flow experiments show that dry oxygen reversibly dopes graphene; doping becomes stronger and more irreversible in the presence of moisture and over long periods of time. We propose that oxygen molecular anions are stabilized by water solvation and electrostatic binding to the silicon dioxide surface.

  16. Suppression of the spin pumping in Pd/Ni{sub 81}Fe{sub 19} bilayers with nano-oxide layer

    SciTech Connect (OSTI)

    Kim, Duck-Ho; Kim, Hong-Hyoun; You, Chun-Yeol [Department of Physics, Inha University, Namgu Incheon 402-751 (Korea, Republic of)

    2011-08-15T23:59:59.000Z

    We demonstrate that the spin pumping effect can be effectively suppressed with a nano-oxide layer. Spin pumping effect manifests itself by an enhancement of the Gilbert damping parameter in normal metal/ferromagnetic hetero-structures, while many spintronics devices prefer smaller damping parameter. Since the spin pumping effect is directly related with the spin dependent interface conductance, we can modify the spin pumping by altering the interface conductance with the nano-oxide layer. We prepared series of Pd/Ni{sub 81}Fe{sub 19} bilayers with different pausing time between Pd and Ni{sub 81}Fe{sub 19} depositions in order to control the interface conductance. The Gilbert damping parameters are determined from the line-width measurements in the ferromagnetic resonance spectra for each pausing time sample. They are 0.0490, 0.0296, 0.0278, and 0.0251 for 0, 6, 30, and 60 s pausing time, respectively. We find that the damping parameter of Pd/Ni{sub 81}Fe{sub 19} is almost recovered to one of the Cu/Ni{sub 81}Fe{sub 19} bilayer with 60 s pausing time, while the static magnetic properties are not noticeably changed.

  17. Effect of nitrogen-doping temperature on the structure and photocatalytic activity of the B,N-doped TiO{sub 2}

    SciTech Connect (OSTI)

    Zhou, Xiaosong [School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640 (China); Peng, Feng, E-mail: cefpeng@scut.edu.c [School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640 (China); Wang, Hongjuan; Yu, Hao; Yang, Jian [School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640 (China)

    2011-01-15T23:59:59.000Z

    B,N-TiO{sub 2} photocatalysts were synthesized by boron doping firstly and subsequently nitrogen doping in NH{sub 3} at variable temperatures. The effects of the nitrogen doping temperature on the structure and photocatalytic activity of the B,N-codoped TiO{sub 2} were investigated. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis diffuse reflectance spectrum (DRS), electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity was evaluated with photocatalytic degradation of methyl orange dye (MO) under visible light and UV-visible light irradiation. The results suggested that the boron and nitrogen can be incorporated into the TiO{sub 2} lattice either interstitially or substitutionally or both, while the Ti-O-B-N structure plays a vital role in photocatalytic activity in visible light region. The optimal nitrogen doping temperature is 550 {sup o}C. Higher temperature may form many oxygen vacancies and Ti{sup 3+} species, resulting in the decrease of photocatalytic activity in visible light. -- Graphical abstract: The changes of photocatalytic activity of B,N-TiO{sub 2} with variable nitrogen doping temperatures are attributed to the transformation of surface structure and oxygen vacancies, and the Ti-O-B-N structure plays a vital role in photocatalytic activity under visible light irradiation. Display Omitted Research highlights: > B,N-TiO{sub 2} photocatalysts are synthesized by boron doping firstly and subsequently nitrogen doping in NH{sub 3} at variable temperatures. > The boron and nitrogen can be incorporated into the TiO{sub 2} lattice either interstitially or substitutionally or both. > The temperature of nitrogen doping affects the transformation of surface structure and oxygen vacancies. > The Ti-O-B-N structure plays an important role in photocatalytic activity under visible light irradiation.

  18. Spectral investigations of Sm{sup 3+}-doped oxyfluorosilicate glasses

    SciTech Connect (OSTI)

    Ramachari, D. [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); Rama Moorthy, L., E-mail: lrmphysics@yahoo.co.in [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); Department of Physics, Chadalawada Ramanamma Engineering College, Renigunta Road, Tirupati 517506 (India); Jayasankar, C.K. [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India)

    2013-09-01T23:59:59.000Z

    Graphical abstract: The figure shows the emission spectra of Sm{sup 3+} doped KNSZL glass for different concentrations. Among the four emission transitions {sup 4}G{sub 5/2} ? {sup 6}H{sub 5/2}, {sup 4}G{sub 5/2} ? {sup 6}H{sub 7/2}, {sup 4}G{sub 5/2} ? {sup 6}H{sub 9/2} and {sup 4}G{sub 5/2} ? {sup 6}H{sub 11/2}, the {sup 4}G{sub 5/2} ? {sup 6}H{sub 7/2} transition of KNSZLSm10 glass is more intense compared with all the transitions. The insert figure shows, the color coordinates (0.59, 0.41) of KNSZLSm10 glass is located on the perimeter of the chromaticity diagram at 592 nm which appears to be closest to the orange color. From these results the KNSZLSm10 glass could be useful for optical amplifiers, waveguides, telecommunications and orange LEDs. - Highlights: • From the DTA, the undoped KNSZL glass more precisely in fiberdrawing. • The XRD pattern confirmed the KNbO{sub 3} nanocrystallites of undoped KNSZL glass. • FTIR and Raman data of KNSZLSm10 glass revealed structural properties. • Judd–Ofelt analysis and decay measurements were carried out. • The optical gain parameter of the investigated glass is 18.13 × 10{sup ?25} cm{sup 2} s. - Abstract: Sm{sub 2}O{sub 3}-doped oxyfluorosilicate glasses were prepared by melt-quenching method. The differential thermal analysis and X-ray diffraction were carried out to investigate the glass transition temperature and structure of precursor glass. Infrared spectroscopy, Raman, optical absorption, photoluminescence and decay measurements were carried out for Sm{sup 3+}-doped oxyfluorosilicate glasses. From the absorption spectrum, the Judd–Ofelt intensity parameters have been evaluated to predict the radiative properties for the emission levels of Sm{sup 3+} ions. The lifetimes of {sup 4}G{sub 5/2} level are found to decrease from 1.17 to 0.93 ms due to the energy transfer, when the concentration of Sm{sup 3+} ions increases from 0.1 to 2.0 mol%. The optical gain parameter (18.13 × 10{sup ?25} cm{sup 2} s) of the investigated glass is found to be higher than the other Sm{sub 2}O{sub 3}-doped glass systems.

  19. Doped H(2)-Filled RF Cavities for Muon Beam Cooling

    SciTech Connect (OSTI)

    Yonehara, K.; Chung, M.; Jansson, A.; Hu, M.; Moretti, A.; Popovic, M.; /Fermilab; Alsharo'a, M.; Johnson, R.P.; Neubauer, M.; Sah, R.; /Muons Inc., Batavia; Rose, D.V.; /Voss Sci., Albuquerque

    2009-05-01T23:59:59.000Z

    RF cavities pressurized with hydrogen gas may provide effective muon beam ionization cooling needed for muon colliders. Recent 805 MHz test cell studies reported below include the first use of SF{sub 6} dopant to reduce the effects of the electrons that will be produced by the ionization cooling process in hydrogen or helium. Measurements of maximum gradient in the Paschen region are compared to a simulation model for a 0.01% SF{sub 6} doping of hydrogen. The observed good agreement of the model with the measurements is a prerequisite to the investigation of other dopants.

  20. Green emission in carbon doped ZnO films

    SciTech Connect (OSTI)

    Tseng, L. T.; Yi, J. B., E-mail: jiabao.yi@unsw.edu.au; Zhang, X. Y.; Xing, G. Z.; Luo, X.; Li, S. [School of Materials Science and Engineering, University of New South Wales, Kensington, NSW, 2052 (Australia); Fan, H. M. [School of Chemical Engineering, Northwest University, Xi'an 710069 (China); Herng, T. S.; Ding, J. [Department of Materials Science and Engineering, National University of Singapore, 119260 (Singapore); Ionescu, M. [Australian Nuclear Science and Technology Organization, (ANSTO), New Illawarra Road, Lucas Heights, NSW 2234 (Australia)

    2014-06-15T23:59:59.000Z

    The emission behavior of C-doped ZnO films, which were prepared by implantation of carbon into ZnO films, is investigated. Orange/red emission is observed for the films with the thickness of 60–100 nm. However, the film with thickness of 200 nm shows strong green emission. Further investigations by annealing bulk ZnO single crystals under different environments, i.e. Ar, Zn or C vapor, indicated that the complex defects based on Zn interstitials are responsible for the strong green emission. The existence of complex defects was confirmed by electron spin resonance (ESR) and low temperature photoluminescence (PL) measurement.

  1. Variable temperature electrochemical strain microscopy of Sm-doped ceria

    SciTech Connect (OSTI)

    Jesse, Stephen [ORNL; Morozovska, A. N. [National Academy of Science of Ukraine, Kiev, Ukraine; Kalinin, Sergei V [ORNL; Eliseev, E. A. [National Academy of Science of Ukraine, Kiev, Ukraine; Yang, Nan [ORNL; Doria, Sandra [ORNL; Tebano, Antonello [ORNL

    2013-01-01T23:59:59.000Z

    Variable temperature electrochemical strain microscopy has been used to study the electrochemical activity of Sm-doped ceria as a function of temperature and bias. The electrochemical strain microscopy hysteresis loops have been collected across the surface at different temperatures and the relative activity at different temperatures has been compared. The relaxation behavior of the signal at different temperatures has been also evaluated to relate kinetic process during bias induced electrochemical reactions with temperature and two different kinetic regimes have been identified. The strongly non-monotonic dependence of relaxation behavior on temperature is interpreted as evidence for water-mediated mechanisms.

  2. Electrically conductive doped block copolymer of polyacetylene and polyisoprene

    DOE Patents [OSTI]

    Aldissi, Mahmoud (Los Alamos, NM)

    1985-01-01T23:59:59.000Z

    An electrically conductive block copolymer of polyisoprene and polyacetyl and a method of making the same are disclosed. The polymer is prepared by first polymerizing isoprene with n-butyllithium in a toluene solution to form an active isoprenyllithium polymer. The active polymer is reacted with an equimolar amount of titanium butoxide and subsequently exposed to gaseous acetylene. A block copolymer of polyisoprene and polyacetylene is formed. The copolymer is soluble in common solvents and may be doped with I.sub.2 to give it an electrical conductivity in the metallic regime.

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

    DOE Patents [OSTI]

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

    2013-08-20T23:59:59.000Z

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

  4. Fabrication of solar cells with counter doping prevention

    DOE Patents [OSTI]

    Dennis, Timothy D; Li, Bo; Cousins, Peter John

    2013-02-19T23:59:59.000Z

    A solar cell fabrication process includes printing of dopant sources over a polysilicon layer over backside of a solar cell substrate. The dopant sources are cured to diffuse dopants from the dopant sources into the polysilicon layer to form diffusion regions, and to crosslink the dopant sources to make them resistant to a subsequently performed texturing process. To prevent counter doping, dopants from one of the dopant sources are prevented from outgassing and diffusing into the other dopant source. For example, phosphorus from an N-type dopant source is prevented from diffusing to a P-type dopant source comprising boron.

  5. Spin drift in highly doped n-type Si

    SciTech Connect (OSTI)

    Kameno, Makoto; Ando, Yuichiro; Shinjo, Teruya [Graduate School of Engineering Science, Osaka University Osaka (Japan); Koike, Hayato; Sasaki, Tomoyuki; Oikawa, Tohru [Advanced Technology Development Center, TDK Cooperation, Chiba (Japan); Suzuki, Toshio [AIT, Akita Research Institute of Advanced Technology, Akita (Japan); Shiraishi, Masashi, E-mail: mshiraishi@kuee.kyoto-u.ac.jp [Graduate School of Engineering Science, Osaka University Osaka (Japan); Graduate School of Engineering, Kyoto University, Kyoto (Japan)

    2014-03-03T23:59:59.000Z

    A quantitative estimation of spin drift velocity in highly doped n-type silicon (Si) at 8?K is presented in this letter. A local two-terminal Hanle measurement enables the detection of a modulation of spin signals from the Si as a function of an external electric field, and this modulation is analyzed by using a spin drift-diffusion equation and an analytical solution of the Hanle-type spin precession. The analyses reveal that the spin drift velocity is linearly proportional to the electric field. The contribution of the spin drift effect to the spin signals is crosschecked by introducing a modified nonlocal four-terminal method.

  6. Spectroscopy of vanadium (III) doped gallium lanthanum sulphide chalcogenide glass

    E-Print Network [OSTI]

    Hughes, M; Rutt, H; Hewak, D

    2014-01-01T23:59:59.000Z

    Vanadium doped gallium lanthanum sulphide glass (V:GLS) displays three absorption bands at 580, 730 and 1155 nm identified by photoluminescence excitation measurements. Broad photoluminescence, with a full width half maximum (FWHM) of 500 nm, is observed peaking at 1500 nm when exciting at 514, 808 and 1064 nm. The fluorescence lifetime and quantum efficiency at 300 K were measured to be 33.4 us and 4 % respectively. From the available spectroscopic data we propose the vanadium ions valence to be 3+ and be in tetrahedral coordination The results indicate potential for development of a laser or optical amplifier based on V:GLS.

  7. Nitrogen-doped Graphene and Its Electrochemical Applications

    SciTech Connect (OSTI)

    Shao, Yuyan; Zhang, Sheng; Engelhard, Mark H.; Li, Guosheng; Shao, Guocheng; Wang, Yong; Liu, Jun; Aksay, Ilhan A.; Lin, Yuehe

    2010-06-04T23:59:59.000Z

    Nitrogen-doped graphene (N-graphene) is obtained by exposing graphene to nitrogen plasma. N-graphene exhibits much higher electrocatalytic activity toward oxygen reduction and H2O2 reduction than graphene, and much higher durability and selectivity than the widely-used expensive Pt. The excellent electrochemical performance of N-graphene is attributed to nitrogen functional groups and the specific properties of graphene. This indicates that N-graphene is promising for applications in electrochemical energy devices (fuel cells, metal-air batteries) and biosensors.

  8. Crystallization and doping of amorphous silicon on low temperature plastic

    DOE Patents [OSTI]

    Kaschmitter, J.L.; Truher, J.B.; Weiner, K.H.; Sigmon, T.W.

    1994-09-13T23:59:59.000Z

    A method or process of crystallizing and doping amorphous silicon (a-Si) on a low-temperature plastic substrate using a short pulsed high energy source in a selected environment, without heat propagation and build-up in the substrate is disclosed. The pulsed energy processing of the a-Si in a selected environment, such as BF3 and PF5, will form a doped micro-crystalline or poly-crystalline silicon (pc-Si) region or junction point with improved mobilities, lifetimes and drift and diffusion lengths and with reduced resistivity. The advantage of this method or process is that it provides for high energy materials processing on low cost, low temperature, transparent plastic substrates. Using pulsed laser processing a high (>900 C), localized processing temperature can be achieved in thin films, with little accompanying temperature rise in the substrate, since substrate temperatures do not exceed 180 C for more than a few microseconds. This method enables use of plastics incapable of withstanding sustained processing temperatures (higher than 180 C) but which are much lower cost, have high tolerance to ultraviolet light, have high strength and good transparency, compared to higher temperature plastics such as polyimide. 5 figs.

  9. Crystallization and doping of amorphous silicon on low temperature plastic

    DOE Patents [OSTI]

    Kaschmitter, James L. (Pleasanton, CA); Truher, Joel B. (Palo Alto, CA); Weiner, Kurt H. (Campbell, CA); Sigmon, Thomas W. (Beaverton, OR)

    1994-01-01T23:59:59.000Z

    A method or process of crystallizing and doping amorphous silicon (a-Si) on a low-temperature plastic substrate using a short pulsed high energy source in a selected environment, without heat propagation and build-up in the substrate. The pulsed energy processing of the a-Si in a selected environment, such as BF3 and PF5, will form a doped micro-crystalline or poly-crystalline silicon (pc-Si) region or junction point with improved mobilities, lifetimes and drift and diffusion lengths and with reduced resistivity. The advantage of this method or process is that it provides for high energy materials processing on low cost, low temperature, transparent plastic substrates. Using pulsed laser processing a high (>900.degree. C.), localized processing temperature can be achieved in thin films, with little accompanying temperature rise in the substrate, since substrate temperatures do not exceed 180.degree. C. for more than a few microseconds. This method enables use of plastics incapable of withstanding sustained processing temperatures (higher than 180.degree. C.) but which are much lower cost, have high tolerance to ultraviolet light, have high strength and good transparency, compared to higher temperature plastics such as polyimide.

  10. Chromatic instabilities in cesium-doped tungsten bronze nanoparticles

    SciTech Connect (OSTI)

    Adachi, Kenji, E-mail: kenji-adachi@ni.smm.co.jp; Ota, Yosuke; Tanaka, Hiroyuki; Okada, Mika; Oshimura, Nobumitsu; Tofuku, Atsushi [Ichikawa Research Laboratories, Sumitomo Metal Mining Co., Ltd., Ichikawa 272-8588 (Japan)

    2013-11-21T23:59:59.000Z

    Nanoparticles of alkali-doped tungsten bronzes are an excellent near-infrared shielding material, but exhibit slight chromatic instabilities typically upon applications of strong ultra-violet light or heating in humid environment, which acts detrimentally to long-life commercial applications. Origin of the chromatic instabilities in cesium-doped tungsten bronze has been investigated, and it has been found that the coloration and bleaching processes comprised electronic exchanges which accelerate or depress the polaron excitation and the localized surface plasmon resonance. Coloration on UV illumination is evidenced by electron diffraction as due to the formation of H{sub x}WO{sub 3}, which is considered to take place in the surface Cs-deficient WO{sub 3} region via the double charge injection mechanism. On the other hand, bleaching on heating in air and in humid environment is shown to accompany the extraction of Cs and electrons from Cs{sub 0.33}WO{sub 3} by X-ray photoelectron spectroscopy and X-ray diffraction analysis and is concluded to be an oxidation of Cs{sub 0.33}WO{sub 3} on the particle surface.

  11. Colossal anisotropy of the magnetic properties of doped lithium nitrodometalates

    SciTech Connect (OSTI)

    Antropov, Vladimir P [Ames Laboratory; Antonov, Victor N [Ames Laboratory

    2014-09-01T23:59:59.000Z

    We present a first-principles investigation of the electronic structure and physical properties of doped lithium nitridometalates Li2(Li1?xMx)N (LiMN) with M = Cr, Mn, Fe, Co, and Ni. The diverse properties include the equilibrium magnetic moments, magneto-crystalline anisotropy, magneto-optical Kerr spectra, and x-ray magnetic circular dichroism. We explain the colossal magnetic anisotropy in LiFeN by its unique electronic structure which ultimately leads to a series of unusual physical properties. The most unique property is a complete suppression of relativistic effects and freezing of orbital moments for in-plane orientation of the magnetization. This leads to the colossal spatial anisotropy of many magnetic properties including energy, Kerr, and dichroism effects. LiFeN is identified as an ultimate single-ion anisotropy system where a nearly insulating state can be produced by a spin orbital coupling alone. A very nontrivial strongly fluctuating and sign changing character of the magnetic anisotropy with electronic 3d-atomic doping is predicted theoretically. A large and highly anisotropic Kerr effect due to the interband transitions between atomic-like Fe 3d bands is found for LiFeN. A giant anisotropy of the x-ray magnetic circular dichroism for the Fe K spectrum and a very weak one for the Fe L2,3 spectra in LiFeN are also predicted.

  12. Near-infrared free carrier absorption in heavily doped silicon

    SciTech Connect (OSTI)

    Baker-Finch, Simeon C., E-mail: simeon.bakerfinch@gmail.com [School of Engineering, Australian National University, Canberra, ACT 0200 (Australia); PV Lighthouse, Coledale, NSW 2515 (Australia); McIntosh, Keith R. [PV Lighthouse, Coledale, NSW 2515 (Australia); Yan, Di; Fong, Kean Chern; Kho, Teng C. [School of Engineering, Australian National University, Canberra, ACT 0200 (Australia)

    2014-08-14T23:59:59.000Z

    Free carrier absorption in heavily doped silicon can have a significant impact on devices operating in the infrared. In the near infrared, the free carrier absorption process can compete with band to band absorption processes, thereby reducing the number of available photons to optoelectronic devices such as solar cells. In this work, we fabricate 18 heavily doped regions by phosphorus and boron diffusion into planar polished silicon wafers; the simple sample structure facilitates accurate and precise measurement of the free carrier absorptance. We measure and model reflectance and transmittance dispersion to arrive at a parameterisation for the free carrier absorption coefficient that applies in the wavelength range between 1000 and 1500?nm, and the range of dopant densities between ?10{sup 18} and 3?×?10{sup 20}?cm{sup ?3}. Our measurements indicate that previously published parameterisations underestimate the free carrier absorptance in phosphorus diffusions. On the other hand, published parameterisations are generally consistent with our measurements and model for boron diffusions. Our new model is the first to be assigned uncertainty and is well-suited to routine device analysis.

  13. Chloride, bromide and iodide scintillators with europium doping

    DOE Patents [OSTI]

    Zhuravleva, Mariya; Yang, Kan

    2014-08-26T23:59:59.000Z

    A halide scintillator material is disclosed where the halide may comprise chloride, bromide or iodide. The material is single-crystalline and has a composition of the general formula ABX.sub.3 where A is an alkali, B is an alkali earth and X is a halide which general composition was investigated. In particular, crystals of the formula ACa.sub.1-yEu.sub.yI.sub.3 where A=K, Rb and Cs were formed as well as crystals of the formula CsA.sub.1-yEu.sub.yX.sub.3 (where A=Ca, Sr, Ba, or a combination thereof and X=Cl, Br or I or a combination thereof) with divalent Europium doping where 0.ltoreq.y.ltoreq.1, and more particularly Eu doping has been studied at one to ten mol %. The disclosed scintillator materials are suitable for making scintillation detectors used in applications such as medical imaging and homeland security.

  14. Structural, optical and ethanol sensing properties of Cu-doped SnO{sub 2} nanowires

    SciTech Connect (OSTI)

    Johari, Anima, E-mail: animajohari@gmail.com; Sharma, Manish [Center for Applied Research in Electronics (CARE), IIT Delhi, Hauz khas, New Delhi-110016 (India); Johari, Anoopshi [THDC Institute of Hydropower Institute of Engineering and Technology, Tehri-249124 (India); Bhatnagar, M. C. [Physics Department, IIT Delhi, Hauz khas, New Delhi-110016 (India)

    2014-04-24T23:59:59.000Z

    In present work, one-dimensional nanostructure of Cu-doped Tin oxide (SnO{sub 2}) was synthesized by using thermal evaporation method in a tubular furnace under Nitrogen (N{sub 2}) ambience. The growth was carried out at atmospheric pressure. SEM and TEM images reveal the growth of wire-like nanostructures of Cu-doped SnO{sub 2} on Si substrate. The XRD analysis confirms that the synthesized SnO{sub 2} nanowires have tetragonal rutile structure with polycrystalline nature and X-ray diffraction pattern also showed that Cu gets incorporated into the SnO{sub 2} lattice. EDX spectra confirm the doping of Cu into SnO{sub 2} nanowires and atomic fraction of Cu in nanowires is ? 0.5 at%. The Vapor Liquid Solid (VLS) growth mechanism for Cu-doped SnO{sub 2} nanowires was also confirmed by EDX spectra. The optical properties of as grown Cu-doped SnO{sub 2} nanowires were studied by using UV-vis spectra which concludes the band gap of about 3.7 eV. As synthesized single Cu-doped SnO{sub 2} nanowire based gas sensor exhibit relatively good performance to ethanol gas. This sensing behaviour offers a suitable application of the Cu-doped SnO{sub 2} nanowire sensor for detection of ethanol gas.

  15. Broad spectral response photodetector based on individual tin-doped CdS nanowire

    SciTech Connect (OSTI)

    Zhou, Weichang, E-mail: wchangzhou@gmail.com, E-mail: dstang@hunnu.edu.cn; Peng, Yuehua; Yin, Yanling; Zhou, Yong; Zhang, Yong; Tang, Dongsheng, E-mail: wchangzhou@gmail.com, E-mail: dstang@hunnu.edu.cn [Key Laboratory of Low-dimensional Quantum Structures and Quantum Control of Ministry of Education, College of Physics and Information Science, Hunan Normal University, Changsha 410081 (China)

    2014-12-15T23:59:59.000Z

    High purity and tin-doped 1D CdS micro/nano-structures were synthesized by a convenient thermal evaporation method. SEM, EDS, XRD and TEM were used to examine the morphology, composition, phase structure and crystallinity of as-prepared samples. Raman spectrum was used to confirm tin doped into CdS effectively. The effect of impurity on the photoresponse properties of photodetectors made from these as-prepared pure and tin-doped CdS micro/nano-structures under excitation of light with different wavelength was investigated. Various photoconductive parameters such as responsivity, external quantum efficiency, response time and stability were analyzed to evaluate the advantage of doped nanowires and the feasibility for photodetector application. Comparison with pure CdS nanobelt, the tin-doped CdS nanowires response to broader spectral range while keep the excellect photoconductive parameters. Both trapped state induced by tin impurity and optical whispering gallery mode microcavity effect in the doped CdS nanowires contribute to the broader spectral response. The micro-photoluminescence was used to confirm the whispering gallery mode effect and deep trapped state in the doped CdS nanowires.

  16. Dynamics of iron-acceptor-pair formation in co-doped silicon

    SciTech Connect (OSTI)

    Bartel, T.; Gibaja, F.; Graf, O.; Gross, D.; Kaes, M.; Heuer, M.; Kirscht, F. [Calisolar GmbH, Magnusstrasse 11, 12489 Berlin (Germany)] [Calisolar GmbH, Magnusstrasse 11, 12489 Berlin (Germany); Möller, C. [CiS Forschungsinstitut für Mikrosensorik und Photovoltaik GmbH, Konrad-Zuse-Str. 14, 99099 Erfurt (Germany) [CiS Forschungsinstitut für Mikrosensorik und Photovoltaik GmbH, Konrad-Zuse-Str. 14, 99099 Erfurt (Germany); TU Ilmenau, Institut für Physik, Weimarer Str. 32, 98693 Ilmenau (Germany); Lauer, K. [CiS Forschungsinstitut für Mikrosensorik und Photovoltaik GmbH, Konrad-Zuse-Str. 14, 99099 Erfurt (Germany)] [CiS Forschungsinstitut für Mikrosensorik und Photovoltaik GmbH, Konrad-Zuse-Str. 14, 99099 Erfurt (Germany)

    2013-11-11T23:59:59.000Z

    The pairing dynamics of interstitial iron and dopants in silicon co-doped with phosphorous and several acceptor types are presented. The classical picture of iron-acceptor pairing dynamics is expanded to include the thermalization of iron between different dopants. The thermalization is quantitatively described using Boltzmann statistics and different iron-acceptor binding energies. The proper understanding of the pairing dynamics of iron in co-doped silicon will provide additional information on the electronic properties of iron-acceptor pairs and may become an analytical method to quantify and differentiate acceptors in co-doped silicon.

  17. Defect Chemistry Study of Nitrogen Doped ZnO Thin Films

    SciTech Connect (OSTI)

    Miami University: Dr. Lei L. Kerr (PI, PD) Wright State University: Dr. David C. Look (PI) and Dr. Zhaoqiang Fang (Co-PI)

    2009-11-29T23:59:59.000Z

    Our team has investigated the defect chemistry of ZnO:N and developed a thermal evaporation (vapor-phase) method to synthesis p-type ZnO:N. Enhanced p-type conductivity of nitrogen doped ZnO via nano/micro structured rods and Zn-rich Co-doping process were studied. Also, an extended X-Ray absorption fine structure study of p-type nitrogen doped ZnO was conducted. Also reported are Hall-effect, photoluminescence, and DLTS studies.

  18. Nonlocal study of the near field radiative heat transfer between two n-doped semiconductors

    E-Print Network [OSTI]

    Singer, F; Joulain, Karl

    2015-01-01T23:59:59.000Z

    We study in this work the near-field radiative heat transfer between two semi-infinite parallel planes of highly n-doped semiconductors. Using a nonlocal model of the dielectric permittivity, usually used for the case of metallic planes, we show that the radiative heat transfer coefficientsaturates as the separation distance is reduced for high doping concentration. These results replace the 1/d${}^2$ infinite divergence obtained in the local model case. Different features of the obtained results are shown to relate physically to the parameters of the materials, mainly the doping concentration and the plasmon frequency.

  19. Reduction of magnetic damping constant of FeCo films by rare-earth Gd doping

    SciTech Connect (OSTI)

    Guo, Xiaobin; Xi, Li, E-mail: xili@lzu.edu.cn; Li, Yue; Han, Xuemeng; Li, Dong; Wang, Zhen; Zuo, Yalu [Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000 (China)

    2014-08-18T23:59:59.000Z

    Magnetic damping constant (?) is one of the key parameters to determine the critical current density of spin-transfer-torque devices and the switching time of magnetization for ultra-high-frequency devices. In this work, Gd doped FeCo films were fabricated to investigate ? based on the ferromagnetic resonance technique. Gd doping not only can efficiently decrease the magnetic inhomogeneity and the extrinsic part of ? but also the Landé g-factor and intrinsic part of ?. The obtained ? was roughly proportional to (g-2){sup 2} and the magnetic anisotropic constant, indicating that the decreased spin-orbit interaction decreases ? by Gd doping.

  20. Thermophotovoltaic energy conversion system having a heavily doped n-type region

    DOE Patents [OSTI]

    DePoy, David M. (Clifton Park, NY); Charache, Greg W. (Clifton Park, NY); Baldasaro, Paul F. (Clifton Park, NY)

    2000-01-01T23:59:59.000Z

    A thermophotovoltaic (TPV) energy conversion semiconductor device is provided which incorporates a heavily doped n-type region and which, as a consequence, has improved TPV conversion efficiency. The thermophotovoltaic energy conversion device includes an emitter layer having first and second opposed sides and a base layer in contact with the first side of the emitter layer. A highly doped n-type cap layer is formed on the second side of the emitter layer or, in another embodiment, a heavily doped n-type emitter layer takes the place of the cap layer.

  1. Ge doped GaN with controllable high carrier concentration for plasmonic applications

    SciTech Connect (OSTI)

    Kirste, Ronny; Hoffmann, Marc P.; Sachet, Edward; Bobea, Milena; Bryan, Zachary; Bryan, Isaac; Maria, Jon-Paul; Collazo, Ramón; Sitar, Zlatko [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695-7919 (United States)] [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695-7919 (United States); Nenstiel, Christian; Hoffmann, Axel [Institut f?r Festkörperphsyik, TU-Berlin, Hardenbergstrasse 36, 10623 Berlin (Germany)] [Institut f?r Festkörperphsyik, TU-Berlin, Hardenbergstrasse 36, 10623 Berlin (Germany)

    2013-12-09T23:59:59.000Z

    Controllable Ge doping in GaN is demonstrated for carrier concentrations of up to 2.4?×?10{sup 20} cm{sup ?3}. Low temperature luminescence spectra from the highly doped samples reveal band gap renormalization and band filling (Burstein-Moss shift) in addition to a sharp transition. Infrared ellipsometry spectra demonstrate the existence of electron plasma with an energy around 3500?cm{sup ?1} and a surface plasma with an energy around 2000?cm{sup ?1}. These findings open possibilities for the application of highly doped GaN for plasmonic devices.

  2. Tensile-strain and doping enhanced direct bandgap optical transition of n{sup +} doped Ge/GeSi quantum wells

    SciTech Connect (OSTI)

    Fan, W. J., E-mail: ewjfan@ntu.edu.sg [NOVITAS, Nanoelectronics Centre of Excellence, School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)

    2013-11-14T23:59:59.000Z

    Band structures of tensile strained and n{sup +} doped Ge/GeSi quantum wells (QWs) are calculated by multiple-band k·p method. The energy dispersion curves of the ? and L conduction subbands are obtained. The effects of tensile strain and n{sup +} doping in Ge on direct bandgap optical gain and spontaneous radiative recombination rate spectra are investigated including the electron leakage from ? to L conduction subbands. Our results show that the optical gain and spontaneous radiative recombination rate can be significantly increased with the tensile strain, n-type doping concentration, and injection carrier density in the Ge QW. The free carrier absorption is calculated and cannot be ignored because of the heavily doped Ge. The pure TM mode polarized net optical gain up to 1153?cm{sup ?1} can be achieved for the Ge/Ge{sub 0.986}Si{sub 0.014} QW with tensile strain of 1.61% and n-type doping concentration of 30?×?10{sup 18}?cm{sup ?3}.

  3. Time-domain detection of current controlled magnetization damping in Pt/Ni{sub 81}Fe{sub 19} bilayer and determination of Pt spin Hall angle

    SciTech Connect (OSTI)

    Ganguly, A.; Haldar, A.; Sinha, J.; Barman, A., E-mail: abarman@bose.res.in, E-mail: del.atkinson@durham.ac.uk [Thematic Unit of Excellence on Nanodevice Technology, Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Kolkata 700098 (India); Rowan-Robinson, R. M.; Jaiswal, S.; Hindmarch, A. T.; Atkinson, D. A., E-mail: abarman@bose.res.in, E-mail: del.atkinson@durham.ac.uk [Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom)

    2014-09-15T23:59:59.000Z

    The effect of spin torque from the spin Hall effect in Pt/Ni{sub 81}Fe{sub 19} rectangular bilayer film was investigated using time-resolved magneto-optical Kerr microscopy. Current flow through the stack resulted in a linear variation of effective damping up to ±7%, attributed to spin current injection from the Pt into the Ni{sub 81}Fe{sub 19}. The spin Hall angle of Pt was estimated as 0.11?±?0.03. The modulation of the damping depended on the angle between the current and the bias magnetic field. These results demonstrate the importance of optical detection of precessional magnetization dynamics for studying spin transfer torque due to spin Hall effect.

  4. Pulsed energy synthesis and doping of silicon carbide

    DOE Patents [OSTI]

    Truher, J.B.; Kaschmitter, J.L.; Thompson, J.B.; Sigmon, T.W.

    1995-06-20T23:59:59.000Z

    A method for producing beta silicon carbide thin films by co-depositing thin films of amorphous silicon and carbon onto a substrate is disclosed, whereafter the films are irradiated by exposure to a pulsed energy source (e.g. excimer laser) to cause formation of the beta-SiC compound. Doped beta-SiC may be produced by introducing dopant gases during irradiation. Single layers up to a thickness of 0.5-1 micron have been produced, with thicker layers being produced by multiple processing steps. Since the electron transport properties of beta silicon carbide over a wide temperature range of 27--730 C is better than these properties of alpha silicon carbide, they have wide application, such as in high temperature semiconductors, including HETEROJUNCTION-junction bipolar transistors and power devices, as well as in high bandgap solar arrays, ultra-hard coatings, light emitting diodes, sensors, etc.

  5. Pulsed energy synthesis and doping of silicon carbide

    DOE Patents [OSTI]

    Truher, Joel B. (San Rafael, CA); Kaschmitter, James L. (Pleasanton, CA); Thompson, Jesse B. (Brentwood, CA); Sigmon, Thomas W. (Beaverton, OR)

    1995-01-01T23:59:59.000Z

    A method for producing beta silicon carbide thin films by co-depositing thin films of amorphous silicon and carbon onto a substrate, whereafter the films are irradiated by exposure to a pulsed energy source (e.g. excimer laser) to cause formation of the beta-SiC compound. Doped beta-SiC may be produced by introducing dopant gases during irradiation. Single layers up to a thickness of 0.5-1 micron have been produced, with thicker layers being produced by multiple processing steps. Since the electron transport properties of beta silicon carbide over a wide temperature range of 27.degree.-730.degree. C. is better than these properties of alpha silicon carbide, they have wide application, such as in high temperature semiconductors, including hetero-junction bipolar transistors and power devices, as well as in high bandgap solar arrays, ultra-hard coatings, light emitting diodes, sensors, etc.

  6. Hydrogen generation under visible light using nitrogen doped titania anodes

    SciTech Connect (OSTI)

    Lin, H.; Rumaiz, A.; Schulz, M.; Huang, C.P.; Sha, S. I.

    2010-06-16T23:59:59.000Z

    Hydrogen is among several energy sources that will be needed to replace the quickly diminishing fossil fuels. Free hydrogen is not available naturally on earth and the current processes require a fossil fuel, methane, to generate hydrogen. Electrochemical splitting of water on titania proposed by Fujishima suffers from low efficiency. The efficiency could be enhanced if full sun spectrum can be utilized. Using pulsed laser deposition technique we synthesized nitrogen doped titanium dioxide (TiO{sub 2-x}N{sub x}) thin films with improved visible light sensitivity. The photoactivity was found to be N concentration dependent. Hydrogen evolution was observed under visible light irradiation (wavelength > 390 nm) without the presence of any organic electron donor.

  7. Bismuth-doped Mg - Al silicate glasses and fibres

    SciTech Connect (OSTI)

    Bufetov, Igor' A; Vel'miskin, V V; Galagan, B I; Denker, B I; Sverchkov, S E; Semjonov, S L; Firstov, Sergei V; Shulman, I L; Dianov, Evgenii M

    2012-09-30T23:59:59.000Z

    This paper compares the optical properties of bulk bismuth-doped Mg - Al silicate glasses prepared in an iridium crucible to those of optical fibres prepared by the powder-in-tube method and having a core identical in composition to the glasses. The bulk glasses and fibres are shown to be similar in luminescence properties. The optical loss in the fibres in their IR luminescence band is about one order of magnitude lower than that in the crucible-melted glasses. The level of losses in the fibres and their luminescence properties suggest that such fibres can be made to lase near 1.15 {mu}m. (optical fibres, lasers and amplifiers. properties and applications)

  8. Structural and magnetic properties of chromium doped zinc ferrite

    SciTech Connect (OSTI)

    Sebastian, Rintu Mary; Thankachan, Smitha; Xavier, Sheena; Mohammed, E. M., E-mail: emmohammed2005@gmail.com [Research Department of Physics, Maharaja's College, Ernakulam, Kerala (India); Joseph, Shaji [Department of Physic, St. Albert's College, Ernakulam, Kerala (India)

    2014-01-28T23:59:59.000Z

    Zinc chromium ferrites with chemical formula ZnCr{sub x}Fe{sub 2?x}O{sub 4} (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) were prepared by Sol - Gel technique. The structural as well as magnetic properties of the synthesized samples have been studied and reported here. The structural characterizations of the samples were analyzed by using X – Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), and Transmission Electron Microscope (TEM). The single phase spinel cubic structure of all the prepared samples was tested by XRD and FTIR. The particle size was observed to decrease from 18.636 nm to 6.125 nm by chromium doping and induced a tensile strain in all the zinc chromium mixed ferrites. The magnetic properties of few samples (x = 0.0, 0.4, 1.0) were investigated using Vibrating Sample Magnetometer (VSM)

  9. Axionic superconductivity in three dimensional doped narrow gap semiconductors

    E-Print Network [OSTI]

    Pallab Goswami; Bitan Roy

    2014-08-07T23:59:59.000Z

    We consider the competition between the conventional s-wave and the triplet Balian-Werthamer or the B-phase pairings in the doped three dimensional narrow gap semiconductors, such as $\\mathrm{Cu}_x\\mathrm{Bi}_2\\mathrm{Se}_3$ and $\\mathrm{Sn}_{1-x}\\mathrm{In}_x\\mathrm{Te}$. When the coupling constants of the two contending channels are comparable, we find a simultaneously time-reversal and parity violating $p + is$ state at low temperatures, which provides an example of dynamic axionic state of matter. In contradistinction to the time-reversal invariant, topological B-phase, the $p + is$ state possesses gapped Majorana fermions as the surface Andreev bound states, which give rise to an anomalous surface thermal Hall effect. The anomalous gravitational and electrodynamic responses of the $p+is$ state can be described by the $\\theta$ vacuum structure, where $\\theta \

  10. Welding and Weldability of Thorium-Doped Iridium Alloys

    SciTech Connect (OSTI)

    David, S.A.; Ohriner, E.K.; King, J.F.

    2000-03-12T23:59:59.000Z

    Ir-0.3%W alloys doped with thorium are currently used as post-impact containment material for radioactive fuel in thermoelectric generators that provide stable electrical power for a variety of outer planetary space exploration missions. Welding and weldability of a series of alloys was investigated using arc and laser welding processes. Some of these alloys are prone to severe hot-cracking during welding. Weldability of these alloys was characterized using Sigmajig weldability test. Hot-cracking is influenced to a great extent by the fusion zone microstructure and composition. Thorium content and welding atmosphere were found to be very critical. The weld cracking behavior in these alloys can be controlled by modifying the fusion zone microstructure. Fusion zone microstructure was found to be controlled by welding process, process parameters, and the weld pool shape.

  11. Defect Chemistry of Yttrium-Doped Barium Zirconate: A Thermodynamic Analysis of Water Uptake

    E-Print Network [OSTI]

    (400-700 °C) solid oxide fuel cells (SOFCs), which alleviate many of the material lifetime-based SOFCs.3 Of known proton conducting oxides, yttrium-doped barium zirconate (BYZ) is particularly

  12. High-Performance Single Layered WSe2 p-FETs with Chemically Doped Contacts

    E-Print Network [OSTI]

    California at Irvine, University of

    by using high work function Pd contacts along with degenerate surface doping of the contacts by patterned by the gate electrode.3 For sub-5 nm gate lengths, this corresponds to channel materials with only 1-2 atomic

  13. Enhancement of Thermoelectric Properties by Modulation-Doping in Silicon Germanium Alloy Nanocomposites

    E-Print Network [OSTI]

    Yu, Bo

    Modulation-doping was theoretically proposed and experimentally proved to be effective in increasing the power factor of nanocomposites (Si[subscript 80]Ge[subscript 20])[subscript 70](Si[subscript 100]B[subscript 5])[subscript ...

  14. Engineering broadband and anisotropic photoluminescence emission from rare earth doped tellurite thin film photonic crystals

    E-Print Network [OSTI]

    Vanhoutte, Michiel

    Broadband and anisotropic light emission from rare-earth doped tellurite thin films is demonstrated using Er[superscript 3+]-TeO[subscript 2] photonic crystals (PhCs). By adjusting the PhC parameters, photoluminescent light ...

  15. Understanding the viability of impurity-band photovoltaics : a case study of S-doped Si

    E-Print Network [OSTI]

    Sullivan, Joseph Timothy, Ph. D. Massachusetts Institute of Technology

    2013-01-01T23:59:59.000Z

    This thesis explores the electronic structure, optical properties, and carrier lifetimes in silicon that is doped with sulfur beyond the equilibrium solid solubility limit, with a focus on applications as an absorber layer ...

  16. Accurate potential drop sheet resistance measurements of laser-doped areas in semiconductors

    SciTech Connect (OSTI)

    Heinrich, Martin, E-mail: mh.seris@gmail.com [Solar Energy Research Institute of Singapore, National University of Singapore, Singapore 117574 (Singapore); NUS Graduate School for Integrative Science and Engineering, National University of Singapore, Singapore 117456 (Singapore); Kluska, Sven; Binder, Sebastian [Fraunhofer Institute for Solar Energy Systems (ISE), Heidenhofstrasse 2, D-79110 Freiburg (Germany); Hameiri, Ziv [The School of Photovoltaic and Renewable Energy Engineering, The University of New South Wales, Sydney NSW 2052 (Australia); Hoex, Bram [Solar Energy Research Institute of Singapore, National University of Singapore, Singapore 117574 (Singapore); Aberle, Armin G. [Solar Energy Research Institute of Singapore, National University of Singapore, Singapore 117574 (Singapore); NUS Graduate School for Integrative Science and Engineering, National University of Singapore, Singapore 117456 (Singapore); Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117456 (Singapore)

    2014-10-07T23:59:59.000Z

    It is investigated how potential drop sheet resistance measurements of areas formed by laser-assisted doping in crystalline Si wafers are affected by typically occurring experimental factors like sample size, inhomogeneities, surface roughness, or coatings. Measurements are obtained with a collinear four point probe setup and a modified transfer length measurement setup to measure sheet resistances of laser-doped lines. Inhomogeneities in doping depth are observed from scanning electron microscope images and electron beam induced current measurements. It is observed that influences from sample size, inhomogeneities, surface roughness, and coatings can be neglected if certain preconditions are met. Guidelines are given on how to obtain accurate potential drop sheet resistance measurements on laser-doped regions.

  17. Scintillation properties of some Ce[sup 3+] and Pr[sup 3+] doped inorganic crystals

    SciTech Connect (OSTI)

    Dorenbos, P.; Visser, R.; Eijk, C.W.E. van (Delft Univ. of Technology (Netherlands). Dept. of Applied Physics); Khaidukov, N.M. (N.S. Kurnakov Inst. of General and Inorganic Chemistry, Moscow (Russian Federation)); Korzhik, M.V. (Inst. of Nuclear Problems, Minsk (Russian Federation))

    1993-08-01T23:59:59.000Z

    The scintillations properties of Ce[sup 3+] and Pr[sup 3+] doped complex fluoride crystals of composition CsGd[sub 2]F[sub 7] and K[sub 2]YF[sub 5] and of Pr[sup 3+] doped Y[sub 3]Al[sub 5]O[sub 12] single crystals were studied by means of x-ray and gamma ray excitation. The Ce[sub 3+] and Pr[sub 3+] doped fluoride crystals show 5d-4f luminescences at wavelengths near 340 nm and 240 nm, respectively. 5d-4f luminescence of Pr[sup 3+] doped Y[sub 3]Al[sub 5]O[sub 12] is observed between 300 and 400 nm. The authors present the absolute light yield in photons/MeV together with results from scintillation decay time experiments.

  18. Structural properties of fluorozirconate-based glass ceramics doped with multivalent europium

    SciTech Connect (OSTI)

    Passlick, C. [Centre for Innovation Competence SiLi-nano registered , Martin Luther University of Halle-Wittenberg, Karl-Freiherr-von-Fritsch-Str. 3, 06120 Halle (Saale) (Germany); Mueller, O.; Luetzenkirchen-Hecht, D.; Frahm, R. [Bergische Universitaet Wuppertal, Gaussstrasse 20, 42097 Wuppertal (Germany); Johnson, J. A. [Department of Biomedical Engineering, University of Tennessee Space Institute, Tullahoma, Tennessee 37388 (United States); Schweizer, S. [Centre for Innovation Competence SiLi-nano registered , Martin Luther University of Halle-Wittenberg, Karl-Freiherr-von-Fritsch-Str. 3, 06120 Halle (Saale) (Germany); Fraunhofer Center for Silicon Photovoltaics CSP, Walter-Huelse-Str. 1, 06120 Halle (Saale) (Germany)

    2011-12-01T23:59:59.000Z

    The structure/property relationships of fluorochlorozirconate glass ceramics as a function of divalent and trivalent europium (Eu) co-doping and thermal processing have been investigated; the influence of doping ratio on the formation of barium chloride (BaCl{sub 2}) nanocrystals therein was elucidated. X-ray absorption near-edge structure spectroscopy shows that the post-thermal annealing changes the Eu valence of the as-poured glass slightly, but during the melting process Eu{sup 3+} is more strongly reduced to Eu{sup 2+}, in particular, when doped as a chloride instead of fluoride compound. The Eu{sup 2+}-to-Eu{sup 3+} doping ratio also plays a significant role in chemical equilibrium in the melt. X-ray diffraction measurements indicate that a higher Eu{sup 2+} fraction leads to a BaCl{sub 2} phase transition from hexagonal to orthorhombic structure at a lower temperature.

  19. Low-temperature electrical transport in B-doped ultrananocrystalline diamond film

    SciTech Connect (OSTI)

    Li, Lin; Zhao, Jing; Hu, Zhaosheng; Quan, Baogang; Li, Junjie, E-mail: jjli@iphy.ac.cn; Gu, Changzhi, E-mail: czgu@iphy.ac.cn [Beijing National Laboratory for Condensed Matter Physics, Institution of Physics Chinese Academy of Sciences, Beijing 100190 (China)

    2014-05-05T23:59:59.000Z

    B-doped ultrananocrystalline diamond (UNCD) films are grown using hot-filament chemical vapor deposition method, and their electrical transport properties varying with temperature are investigated. When the B-doped concentration of UNCD film is low, a step-like increase feature of the resistance is observed with decreasing temperature, reflecting at least three temperature-modified electronic state densities at the Fermi level according to three-dimensional Mott's variable range hopping transport mechanism, which is very different from that of reported B-doped nanodiamond. With increasing B-doped concentration, a superconductive transformation occurs in the UNCD film and the highest transformation temperature of 5.3?K is observed, which is higher than that reported for superconducting nanodiamond films. In addition, the superconducting coherence length is about 0.63?nm, which breaks a reported theoretical and experimental prediction about ultra-nanoscale diamond's superconductivity.

  20. Structure-property Relationships in Pure and Doped Epitaxial Tungsten Trioxide Thin Films

    E-Print Network [OSTI]

    Structure-property Relationships in Pure and Doped Epitaxial Tungsten Trioxide Thin Films Principal-property relationships of well- defined epitaxial tungsten trioxide (WO3) films with and without dopants, and thereby

  1. Electronic and magnetic properties of Fe and Mn doped two dimensional hexagonal germanium sheets

    SciTech Connect (OSTI)

    Soni, Himadri R., E-mail: himadri.soni@gmail.com; Jha, Prafulla K., E-mail: himadri.soni@gmail.com [Department of Physics, Maharaja Krishnakumarsinhji Bhavnagar University, Bhavnagar-364001 (India)

    2014-04-24T23:59:59.000Z

    Using first principles density functional theory calculations, the present paper reports systematic total energy calculations of the electronic properties such as density of states and magnetic moment of pristine and iron and manganese doped two dimensional hexagonal germanium sheets.

  2. On the design of single electron transistors for the measurement of spins in phosphorus doped silicon

    E-Print Network [OSTI]

    Randeria, Mallika

    2012-01-01T23:59:59.000Z

    Phosphorus doped silicon is a prime candidate for spin based qubits. We plan to investigate a novel hybrid technique that combines the advantages of spin selective optical excitations with that of electrical readout ...

  3. Evolution of the spin-state transition with doping in La??xSrxCoO?

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

    Smith, R. X.; Hoch, M. J. R.; Moulton, W. G.; Kuhns, P. L.; Reyes, A. P.; Boebinger, G. S.; Zheng, H.; Mitchell, J. F.

    2012-08-01T23:59:59.000Z

    The thermally induced spin-state transition of Co³? ions in the cobaltite LaCoO?, found at temperatures in the range 40 to 120 K, has been the subject of extensive experimental and theoretical investigation. Much less is known about what happens to the spin-state transition in hole-doped La??xSrxCoO? (LSCO). The present ¹³?La NMR experiments show that spin-state transitions persist in nanoscale hole-poor regions of the inhomogeneous doped material. In fact, thermally induced spin-state transitions remain important for doping levels close to the metal-insulator critical concentration of xC=0.17. This finding suggests that the unusual glassy behavior seen in doped LSCO for x<0.18 results from the interplay of spin-state transitions in hole-poor regions and ferromagnetism in hole-rich regions.

  4. Properties of Structurally Excellent N-doped TiO2 Rutile. | EMSL

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

    Citation: Chambers SA, SH Cheung, V Shutthanandan, S Thevuthasan, MK Bowman, and AG Joly.2007."Properties of Structurally Excellent N-doped TiO2 Rutile."Chemical Physics...

  5. acid-doped polybenzimidazole membranes: Topics by E-print Network

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

    R. Daik; A. Musa 8 Comparative study of the break in process of post doped and sol-gel high temperature proton exchange membrane fuel cells Energy Storage, Conversion and...

  6. Strain Determination in Electrochemically Doped Single-Walled Carbon Nanotubes via Raman Spectroscopy

    E-Print Network [OSTI]

    Nabben, Reinhard

    batteries,4 and actuators.5 Doping the nanotubes is an important method to influence their electronic) at 1600 cm-1 with a displace- ment pattern derived from the E2g bond-stretching mode of graphite

  7. Electronic properties of H and D doped ZnO epitaxial films. ...

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

    of H and D doped ZnO epitaxial films. Abstract: ZnO epitaxial films grown by pulsed laser deposition in an ambient of H2 or D2 exhibit qualitatively different electronic...

  8. Ferromagnetism in Ti-Doped ZnO Nanoclusters above Room Temperature...

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

    increase of temperature. Citation: Antony J, S Pendyala, DE McCready, MH Engelhard, D Meyer, AM Sharma, and Y Qiang.2006."Ferromagnetism in Ti-Doped ZnO Nanoclusters above Room...

  9. Silicon-germanium saturable absorbers and erbium-doped waveguides for integrated mode-locked lasers

    E-Print Network [OSTI]

    Byun, Hyunil

    2006-01-01T23:59:59.000Z

    In this thesis, Silicon-Germanium (SiGe) Saturable Bragg Reflectors (SBR) and Erbium-doped waveguide chips are fabricated and characterized as crucial components for integration of a mode-locked laser on a Si-chip. The ...

  10. Luminescence dynamics and waveguide applications of europium doped gallium nitride powder

    E-Print Network [OSTI]

    Lipson, Michal

    Luminescence dynamics and waveguide applications of europium doped gallium nitride powder Carl B, bismuth shot, and europium ingot in an ammonia ambient to initially obtain chunks of the desired material

  11. Structural properties of fluorozirconate-based glass ceramics doped with multivalent europium

    SciTech Connect (OSTI)

    PaBlick, C.; Müller, O.; Lützenkirchen-Hecht, D.; Frahm, R.; Johnson, J.A.; Schweizer, S. (U. Halle); (Bergische); (Tennessee-C)

    2012-10-10T23:59:59.000Z

    The structure/property relationships of fluorochlorozirconate glass ceramics as a function of divalent and trivalent europium (Eu) co-doping and thermal processing have been investigated; the influence of doping ratio on the formation of barium chloride (BaCl2) nanocrystals therein was elucidated. X-ray absorption near-edge structure spectroscopy shows that the post-thermal annealing changes the Eu valence of the as-poured glass slightly, but during the melting process Eu3+ is more strongly reduced to Eu2+, in particular, when doped as a chloride instead of fluoride compound. The Eu2+-to-Eu3+ doping ratio also plays a significant role in chemical equilibrium in the melt. X-ray diffraction measurements indicate that a higher Eu2+ fraction leads to a BaCl2 phase transition from hexagonal to orthorhombic structure at a lower temperature.

  12. Ultra High p-doping Material Research for GaN Based Light Emitters

    SciTech Connect (OSTI)

    Vladimir Dmitriev

    2007-06-30T23:59:59.000Z

    The main goal of the Project is to investigate doping mechanisms in p-type GaN and AlGaN and controllably fabricate ultra high doped p-GaN materials and epitaxial structures. Highly doped p-type GaN-based materials with low electrical resistivity and abrupt doping profiles are of great importance for efficient light emitters for solid state lighting (SSL) applications. Cost-effective hydride vapor phase epitaxial (HVPE) technology was proposed to investigate and develop p-GaN materials for SSL. High p-type doping is required to improve (i) carrier injection efficiency in light emitting p-n junctions that will result in increasing of light emitting efficiency, (ii) current spreading in light emitting structures that will improve external quantum efficiency, and (iii) parameters of Ohmic contacts to reduce operating voltage and tolerate higher forward currents needed for the high output power operation of light emitters. Highly doped p-type GaN layers and AlGaN/GaN heterostructures with low electrical resistivity will lead to novel device and contact metallization designs for high-power high efficiency GaN-based light emitters. Overall, highly doped p-GaN is a key element to develop light emitting devices for the DOE SSL program. The project was focused on material research for highly doped p-type GaN materials and device structures for applications in high performance light emitters for general illumination P-GaN and p-AlGaN layers and multi-layer structures were grown by HVPE and investigated in terms of surface morphology and structure, doping concentrations and profiles, optical, electrical, and structural properties. Tasks of the project were successfully accomplished. Highly doped GaN materials with p-type conductivity were fabricated. As-grown GaN layers had concentration N{sub a}-N{sub d} as high as 3 x 10{sup 19} cm{sup -3}. Mechanisms of doping were investigated and results of material studies were reported at several International conferences providing better understanding of p-type GaN formation for Solid State Lighting community. Grown p-type GaN layers were used as substrates for blue and green InGaN-based LEDs made by HVPE technology at TDI. These results proved proposed technical approach and facilitate fabrication of highly conductive p-GaN materials by low-cost HVPE technology for solid state lighting applications. TDI has started the commercialization of p-GaN epitaxial materials.

  13. Doping Cu{sub 2}O in Electrolyte Solution: Dopant Incorporation, Atomic Structures and Electrical Properties

    SciTech Connect (OSTI)

    Tao, Meng; Zhang, Qiming

    2013-11-24T23:59:59.000Z

    We have pursued a number of research activities between April 2010 and April 2011: ? A detailed study on n-type doping in Cu2O by Br; ? An analysis of natural resource limitations to terawatt-scale solar cells; ? Attempt to achieve a 1.4-eV direct band gap in Ni sulfides (NiSx); ? First-principles studies of doping in Cu2O and electronic structures of NiSx.

  14. Amplification from Nd3+ doped SiTi solgel channel waveguides

    E-Print Network [OSTI]

    Arie, Ady

    Amplification from Nd3+ doped Si­Ti sol­gel channel waveguides Asher Peled a,*, Menachem Nathan based on a Nd3+ doped sol­gel tapered rib waveguide. The sol­gel matrix composition is 50SiO2:50TiO2 into and out of the rib waveguide. A photoluminescence lifetime of 138 ls and a pump absorption cross

  15. The Effects and Applications of Erbium Doped Fiber Fabry-Perot Interferometers

    E-Print Network [OSTI]

    Taylor, Justin K.

    2010-07-14T23:59:59.000Z

    THE EFFECTS AND APPLICATIONS OF ERBIUM DOPED FIBER FABRY-PEROT INTERFEROMETERS A Thesis by JUSTIN KEITH TAYLOR Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE May 2009 Major Subject: Electrical Engineering THE EFFECTS AND APPLICATIONS OF ERBIUM DOPED FIBER FABRY-PEROT INTERFEROMETERS A Thesis by JUSTIN KEITH TAYLOR Submitted to the Office of Graduate...

  16. Supporting information for: Na-doped p-type ZnO , Faxian Xiu2

    E-Print Network [OSTI]

    Yang, Zheng

    S1 Supporting information for: Na-doped p-type ZnO microwires Wei Liu1* , Faxian Xiu2 , Ke Sun1 flow was switched to argon followed by cooling to room temperature. After the growth, high-density Zn distribution of the Na Doped ZnO microwire 1.3 EDX line scans spectra #12;S3 Figure S3 a) a typical TEM image

  17. Metal-doped single-walled carbon nanotubes and production thereof

    DOE Patents [OSTI]

    Dillon, Anne C.; Heben, Michael J.; Gennett, Thomas; Parilla, Philip A.

    2007-01-09T23:59:59.000Z

    Metal-doped single-walled carbon nanotubes and production thereof. The metal-doped single-walled carbon nanotubes may be produced according to one embodiment of the invention by combining single-walled carbon nanotube precursor material and metal in a solution, and mixing the solution to incorporate at least a portion of the metal with the single-walled carbon nanotube precursor material. Other embodiments may comprise sputter deposition, evaporation, and other mixing techniques.

  18. Hydrothermal synthesis and characteristics of anions-doped calcium molybdate red powder phosphors

    SciTech Connect (OSTI)

    Shi, Shikao, E-mail: ssk02@mails.tsinghua.edu.cn [College of Chemistry and Materials Science, Hebei Normal University, Shijiazhuang 050024 (China); Zhang, Yan; Liu, Qing [College of Chemistry and Materials Science, Hebei Normal University, Shijiazhuang 050024 (China); Zhou, Ji [State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing 100084 (China)

    2013-10-15T23:59:59.000Z

    Graphical abstract: - Highlights: • Four anion-doped CaMoO{sub 4}:Eu{sup 3+} red phosphors were prepared by hydrothermal approach. • Some samples exhibit nearly spherical morphology and well-distributed fine particles. • The red luminescence can be obviously enhanced after certain amount of anion doping. • The improved phosphor system is a potential candidate for white LED applications. - Abstract: Applying hydrothermal and subsequent heat-treatment process, CaMoO{sub 4}:Eu{sup 3+} was doped with four anions (SiO{sub 3}{sup 2?}, PO{sub 4}{sup 3?}, SO{sub 4}{sup 2?} and ClO{sub 3}{sup ?}) to prepare fine red powder phosphors. The introduction of small amount of anions into the host had little influence on the structure, which was confirmed by X-ray diffraction patterns. The anion-doped phosphor samples (except SiO{sub 3}{sup 2?}) exhibited nearly spherical morphology, and the particle sizes were in the range of 0.3–0.4 ?m for SO{sub 4}{sup 2?}-doped samples, and 0.8–1.2 ?m for PO{sub 4}{sup 3?} and ClO{sub 3}{sup ?}-doped samples. Excited with 395 nm near-UV light, all samples showed typical Eu{sup 3+} red emission at 615 nm, and PO{sub 4}{sup 3?}, SO{sub 4}{sup 2?} and ClO{sub 3}{sup ?}-doped samples enhanced the red luminescence as compared with the individual CaMoO{sub 4}:Eu{sup 3+} sample. In particular, relative emission intensity for optimum ClO{sub 3}{sup ?}-doped phosphors reached more than 6-fold that of the commercial red phosphor, which is highly desirable for the powder phosphors used in the solid-state lighting industry.

  19. Iron-Doped Carbon Aerogels: Novel Porous Substrates for Direct Growth of Carbon Nanotubes

    SciTech Connect (OSTI)

    Steiner, S A; Baumann, T F; Kong, J; Satcher, J H; Dresselhaus, M S

    2007-02-15T23:59:59.000Z

    We present the synthesis and characterization of Fe-doped carbon aerogels (CAs) and demonstrate the ability to grow carbon nanotubes directly on monoliths of these materials to afford novel carbon aerogel-carbon nanotube composites. Preparation of the Fe-doped CAs begins with the sol-gel polymerization of the potassium salt of 2,4-dihydroxybenzoic acid with formaldehyde, affording K{sup +}-doped gels that can then be converted to Fe{sup 2+}- or Fe{sup 3+}-doped gels through an ion exchange process, dried with supercritical CO{sub 2} and subsequently carbonized under an inert atmosphere. Analysis of the Fe-doped CAs by TEM, XRD and XPS revealed that the doped iron species are reduced during carbonization to form metallic iron and iron carbide nanoparticles. The sizes and chemical composition of the reduced Fe species were related to pyrolysis temperature as well as the type of iron salt used in the ion exchange process. Raman spectroscopy and XRD analysis further reveal that, despite the presence of the Fe species, the CA framework is not significantly graphitized during pyrolysis. The Fe-doped CAs were subsequently placed in a thermal CVD reactor and exposed to a mixture of CH{sub 4} (1000 sccm), H{sub 2} (500 sccm), and C{sub 2}H{sub 4} (20 sccm) at temperatures ranging from 600 to 800 C for 10 minutes, resulting in direct growth of carbon nanotubes on the aerogel monoliths. Carbon nanotubes grown by this method appear to be multiwalled ({approx}25 nm in diameter and up to 4 mm long) and grow through a tip-growth mechanism that pushes catalytic iron particles out of the aerogel framework. The highest yield of CNTs were grown on Fe-doped CAs pyrolyzed at 800 C treated at CVD temperatures of 700 C.

  20. Luminescent studies of fluorescent chromophore-doped silica aerogels for flat panel display applications

    SciTech Connect (OSTI)

    Glauser, S.A.C. [California Univ., Davis, CA (United States). Dept. of Applied Science; Lee, H.W.H. [Lawrence Livermore National Lab., CA (United States)

    1997-04-01T23:59:59.000Z

    The remarkable optical and electronic properties of doped and undoped silica aerogels establish their utility as unique, mulitfunctional host materials for fluorescent dyes and other luminescent materials for display and imaging applications. We present results on the photoluminescence, absorption, and photoluminescence excitation spectra of undoped silica aerogels and aerogels doped with Er{sup 3+}, rhodamine 6G (R6G), and fluorescein. 4 refs., 12 figs.

  1. UID-GaN doping1016 cm-3 2 m 5 m2 m

    E-Print Network [OSTI]

    Boyer, Edmond

    2 µm Drain Silicon UID-GaN ­ doping1016 cm-3 1.1 µm 30 nm 2 µm GateSource 2 µm 5 µm2 µm AirAir Al0.25GaN ­ doping1015 cm-3 30 nm Scalable normally-off MIS-HEMT using Fluorine implantation below-Electron-Mobility-Transistor (MIS-HEMT) is proposed. The design is based on the implantation of fluorine ions in the GaN layer below

  2. Cr Atom Alignment in Cr-Delta-Doped GaN

    SciTech Connect (OSTI)

    Kimura, S.; Emura, S.; Zhou, Y. K.; Choi, S. W.; Yamauchi, Y.; Hasegawa, S.; Asahi, H. [Institute of Scientific and Industrial Research, Osaka University, 8-1, Mihogaoka, Osaka, 567-0047 (Japan); Ofuchi, H. [SPring-8 / Japan Synchrotron Radiation Research Institute (JASRI), Sayo, Hyogo 679-5198 (Japan); Nakata, Y. [College of Science and Engineering, Iwaki Meisei University, Iwaki, Fukushima 970-8551 (Japan)

    2007-02-02T23:59:59.000Z

    Structural properties and Cr atom alignments in Cr-delta doped GaN grown by molecular beam epitaxy are studied with transmission electron microscopy and X-ray absorption fine structure (XAFS) measurements. It is found that the environment around Cr atoms in delta-doped samples is dramatically changed under various growth conditions. The XAFS analysis of these synthesized layers suggests that new Cr-related complexes are grown.

  3. Controlling ferromagnetism of (In,Fe)As semiconductors by electron doping

    SciTech Connect (OSTI)

    Dang Vu, Nguyen; Fukushima, Tetsuya; Katayama-Yoshida, Hiroshi [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan); Sato, Kazunori [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2014-02-21T23:59:59.000Z

    Based on experimental results, using the Korringa-Kohn-Rostoker coherent potential approximation (KKR-CPA) method and Monte Carlo simulation, we study the mechanism of ferromagnetic behavior of (In,Fe)As. We show that with doped Be atoms occupying in interstitial sites, chemical pair interactions between atoms and magnetic exchange interactions between Fe atoms change due to electron concentration. Therefore, by controlling the doping process, magnetic behavior of (In,Fe)As is controlled and ferromagnetism is observed in this semiconductor.

  4. Method of making self-aligned lightly-doped-drain structure for MOS transistors

    DOE Patents [OSTI]

    Weiner, Kurt H. (San Jose, CA); Carey, Paul G. (Mountain View, CA)

    2001-01-01T23:59:59.000Z

    A process for fabricating lightly-doped-drains (LDD) for short-channel metal oxide semiconductor (MOS) transistors. The process utilizes a pulsed laser process to incorporate the dopants, thus eliminating the prior oxide deposition and etching steps. During the process, the silicon in the source/drain region is melted by the laser energy. Impurities from the gas phase diffuse into the molten silicon to appropriately dope the source/drain regions. By controlling the energy of the laser, a lightly-doped-drain can be formed in one processing step. This is accomplished by first using a single high energy laser pulse to melt the silicon to a significant depth and thus the amount of dopants incorporated into the silicon is small. Furthermore, the dopants incorporated during this step diffuse to the edge of the MOS transistor gate structure. Next, many low energy laser pulses are used to heavily dope the source/drain silicon only in a very shallow region. Because of two-dimensional heat transfer at the MOS transistor gate edge, the low energy pulses are inset from the region initially doped by the high energy pulse. By computer control of the laser energy, the single high energy laser pulse and the subsequent low energy laser pulses are carried out in a single operational step to produce a self-aligned lightly-doped-drain-structure.

  5. Electronic structure evolution in doping of fullerene (C{sub 60}) by molybdenum trioxide

    SciTech Connect (OSTI)

    Wang, Chenggong [Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627 (United States); Gao, Yongli, E-mail: ygao@pas.rochester.edu [Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627 (United States); Hunan Key Laboratory for Super-microstructure and Ultrafast Process, College of Physics and Electronics, Central South University, Changsha, Hunan 410083 (China)

    2014-09-15T23:59:59.000Z

    Molybdenum oxide doping of fullerene has been investigated using ultraviolet photoemission spectroscopy (UPS), X-ray photoemission spectroscopy (XPS), and inverse photoemission spectroscopy (IPES). The lowest unoccupied molecular orbital and the highest occupied molecular orbital (HOMO) can be observed directly with IPES and UPS. It is observed that the Fermi level position in fullerene is modified by molybdenum oxide doping, and the HOMO onset is shifted to less than 0.3?eV below the Fermi level. The energy level shift is found to saturate at doping ratio of 18%. Till this stage, the shift depends on the doping concentration in a semi-logarithmic scale, with a slope substantially higher than that of the traditional semiconductor theory. The XPS results indicate that charge transfer continues beyond the energy level shift saturation till the doping ratio reaches 66% as evidenced by the Mo{sup 5+} component. At higher doping concentration, there is more Mo{sup 6+} component, which indicates the saturation of the charge transfer between MoO{sub x} and C{sub 60}.

  6. Vibration responses of h-BN sheet to charge doping and external strain

    SciTech Connect (OSTI)

    Yang, Wei; Yang, Yu; Zheng, Fawei [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China)] [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China); Zhang, Ping, E-mail: zhang-ping@iapcm.ac.cn [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China) [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China); Beijing Computational Science Research Center, Beijing 100084 (China)

    2013-12-07T23:59:59.000Z

    Based on density functional theory and density functional perturbation theory calculations, we systematically investigate the vibration responses of h-BN sheet to charge doping and external strains. It is found that under hole doping, the phonon frequencies of the ZO and TO branches at different wave vector q shift linearly with different slopes. Under electron doping, although the phonon frequencies shift irregularly, the shifting values are different at different phonon wave vectors. Interestingly, we find that external strain can restrain the irregular vibration responses of h-BN sheet to electron doping. The critical factor is revealed to be the relative position of the nearly free electron and boron p{sub z} states of h-BN sheet. Under external strains, the vibration responses of h-BN sheet are also found to be highly dependent on the phonon branches. Different vibration modes at different q points are revealed to be responsible for the vibration responses of h-BN sheet to charge doping and external strain. Our results point out a new way to detect the doping or strain status of h-BN sheet by measuring the vibration frequencies at different wave vector.

  7. Method and closing pores in a thermally sprayed doped lanthanum chromite interconnection layer

    DOE Patents [OSTI]

    Singh, P.; Ruka, R.J.

    1995-02-14T23:59:59.000Z

    A dense, substantially gas-tight electrically conductive interconnection layer is formed on an air electrode structure of an electrochemical cell by (A) providing an air electrode surface; (B) forming on a selected portion of the electrode surface, a layer of doped LaCrO{sub 3} particles doped with an element or elements selected from Ca, Sr, Ba, Mg, Co, Ni, Al and mixtures thereof by thermal spraying doped LaCrO{sub 3} particles, either by plasma arc spraying or flame spraying; (C) depositing a mixture of CaO and Cr{sub 2}O{sub 3} on the surface of the thermally sprayed layer; and (D) heating the doped LaCrO{sub 3} layer coated with CaO and Cr{sub 2}O{sub 3} surface deposit at from about 1,000 C to 1,200 C to substantially close the pores, at least at a surface, of the thermally sprayed doped LaCrO{sub 3} layer. The result is a dense, substantially gas-tight, highly doped, electrically conductive interconnection material bonded to the electrode surface. A solid electrolyte layer can be applied to the nonselected portion of the air electrode. A fuel electrode can be applied to the solid electrolyte, to form an electrochemical cell, for example for generation of electrical power. 5 figs.

  8. Method and closing pores in a thermally sprayed doped lanthanum chromite interconnection layer

    DOE Patents [OSTI]

    Singh, Prabhakar (Export, PA); Ruka, Roswell J. (Pittsburgh, PA)

    1995-01-01T23:59:59.000Z

    A dense, substantially gas-tight electrically conductive interconnection layer is formed on an air electrode structure of an electrochemical cell by (A) providing an air electrode surface; (B) forming on a selected portion of the electrode surface, a layer of doped LaCrO.sub.3 particles doped with an element or elements selected from Ca, Sr, Ba, Mg, Co, Ni, Al and mixtures thereof by thermal spraying doped LaCrO.sub.3 particles, either by plasma arc spraying or flame spraying; (C) depositing a mixture of CaO and Cr.sub.2 O.sub.3 on the surface of the thermally sprayed layer; and (D) heating the doped LaCrO.sub.3 layer coated with CaO and Cr.sub.2 O.sub.3 surface deposit at from about 1000.degree. C. to 1200.degree. C. to substantially close the pores, at least at a surface, of the thermally sprayed doped LaCrO.sub.3 layer. The result is a dense, substantially gas-tight, highly doped, electrically conductive interconnection material bonded to the electrode surface. A solid electrolyte layer can be applied to the nonselected portion of the air electrode. A fuel electrode can be applied to the solid electrolyte, to form an electrochemical cell, for example for generation of electrical power.

  9. Effect of doping on growth and field emission properties of spherical carbon nanotube tip placed over cylindrical surface

    SciTech Connect (OSTI)

    Santolia, Isha; Tewari, Aarti; Sharma, Suresh C.; Sharma, Rinku [Department of Applied Physics, Delhi Technological University, Shahbad Daulatpur, Bawana Road, Delhi 110 042 (India)

    2014-06-15T23:59:59.000Z

    Theoretical investigations to study the effect of doping of hetero-atoms on the growth and field emission properties of Carbon Nanotubes (CNTs) tip placed over a cylindrical surface in complex plasma have been carried out. A theoretical model incorporating kinetics of plasma species such as electron, ions, and neutral atoms including doping elements like nitrogen (N) and boron (B) and energy balance of CNTs in a complex plasma has been developed. The effect of doping elements of N and B on the growth of CNTs, namely, the tip radius has been carried out for typical glow discharge plasma parameters. It is found that N and B as doping elements affect the radius of CNTs extensively. We obtain small radii of CNT doped with N and large radius of CNT doped with B. The field emission characteristics from CNTs have therefore been suggested on the basis of results obtained. Some of theoretical results are in compliance with the existing experimental observations.

  10. Comparative investigation of InGaP/GaAs pseudomorphic field-effect transistors with triple doped-channel profiles

    SciTech Connect (OSTI)

    Tsai, Jung-Hui, E-mail: jhtsai@nknucc.nknu.edu.tw [National Kaohsiung Normal University, Department of Electronic Engineering, Taiwan (China); Guo, Der-Feng [Air Force Academy, Department of Electronic Engineering, Taiwan (China); Lour, Wen-Shiung [National Taiwan Ocean University, Department of Electrical Engineering, Taiwan (China)

    2011-09-15T23:59:59.000Z

    In this article, the comparison of DC performance on InGaP/GaAs pseudomorphic field-effect transistors with tripe doped-channel profiles is demonstrated. As compared to the uniform and high-medium-low doped-channel devices, the low-medium-high doped-channel device exhibits the broadest gate voltage swing and the best device linearity because more twodimensional electron gases are formed in the heaviest doped channel to enhance the magnitude of negative threshold voltage. Experimentally, the transconductance within 50% of its maximum value for gate voltage swing is 4.62 V in the low-medium-high doped-channel device, which is greater than 3.58 (3.30) V in the uniform (high-medium-low) doped-channel device.

  11. Red light emission by photoluminescence and electroluminescence from Pr-doped GaN on Si substrates

    E-Print Network [OSTI]

    Steckl, Andrew J.

    Red light emission by photoluminescence and electroluminescence from Pr-doped GaN on Si substrates to higher level Er3 transitions. In this letter, we report on Pr-doped GaN growth on Si 111 substrates from Pr-doped GaN thin films grown on Si 111 . The GaN was grown by molecular beam epitaxy using solid

  12. Green emission from Er-doped GaN grown by molecular beam epitaxy on Si substrates

    E-Print Network [OSTI]

    Steckl, Andrew J.

    Green emission from Er-doped GaN grown by molecular beam epitaxy on Si substrates R. Birkhahn and A grown by MBE on sapphire substrates. In this letter, we report on Er-doped GaN growth experiments on Si Er-doped -GaN thin films grown on Si 111 . The GaN was grown by molecular beam epitaxy using solid

  13. Fabrication of Chemically Doped, High Upper Critical Field Magnesium Diboride Superconducting Wires

    SciTech Connect (OSTI)

    Marzik, James, V.

    2005-10-13T23:59:59.000Z

    Controlled chemical doping of magnesium diboride (MgB2) has been shown to substantially improve its superconducting properties to the levels required for high field magnets, but the doping is difficult to accomplish through the usual route of solid state reaction and diffusion. Further, superconducting cables of MgB2 are difficult to fabricate because of the friable nature of the material. In this Phase I STTR project, doped and undoped boron fibers were made by chemical vapor deposition (CVD). Several >100m long batches of doped and undoped fiber were made by CVD codeposition of boron plus dopants. Bundles of these fibers infiltrated with liquid magnesium and subsequently converted to MgB2 to form Mg-MgB2 metal matrix composites. In a parallel path, doped boron nano-sized powder was produced by a plasma synthesis technique, reacted with magnesium to produce doped MgB2 superconducting ceramic bodies. The doped powder was also fabricated into superconducting wires several meters long. The doped boron fibers and powders made in this program were fabricated into fiber-metal composites and powder-metal composites by a liquid metal infiltration technique. The kinetics of the reaction between boron fiber and magnesium metal was investigated in fiber-metal composites. It was found that the presence of dopants had significantly slowed the reaction between magnesium and boron. The superconducting properties were measured for MgB2 fibers and MgB2 powders made by liquid metal infiltration. Properties of MgB2 products (Jc, Hc2) from Phase I are among the highest reported to date for MgB2 bulk superconductors. Chemically doped MgB2 superconducting magnets can perform at least as well as NbTi and NbSn3 in high magnetic fields and still offer an improvement over the latter two in terms of operating temperature. These characteristics make doped MgB2 an effective material for high magnetic field applications, such as magnetic confined fusion, and medical MRI devices. Developing fusion as an energy source will dramatically reduce energy costs, global warming, and radioactive waste. Cheaper and more efficient medical MRI devices could lower examination costs, find potential health problems earlier, and thus also benefit society as a whole. Other potential commercial applications for this material are devices for the generation and storage of electrical power, thus lowering the cost of delivered electricity.

  14. Observation of an electron band above the Fermi level in FeTe?.??Se?.?? from in-situ surface doping

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

    Zhang, P. [Chinese Academy of Sciences (CAS), Beijing (China); Gu, G. D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Richard, P. [Chinese Academy of Sciences (CAS), Beijing (China); Collaborative Innovation Center of Quantum Matter, Beijing (China); Xu, N. [Chinese Academy of Sciences (CAS), Beijing (China); Paul Scherrer Inst. (PSI), Villigen (Switzerland); Xu, Y. -M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ma, J. [Chinese Academy of Sciences (CAS), Beijing (China); Qian, T. [Chinese Academy of Sciences (CAS), Beijing (China); Fedorov, A. V. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Denlinger, J. D. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ding, H. [Chinese Academy of Sciences (CAS), Beijing (China); Collaborative Innovation Center of Quantum Matter, Beijing (China)

    2014-10-27T23:59:59.000Z

    We used in-situ potassium (K) evaporation to dope the surface of the iron-based superconductor FeTe?.??Se?.??. The systematic study of the bands near the Fermi level confirms that electrons are doped into the system, allowing us to tune the Fermi level of this material and to access otherwise unoccupied electronic states. In particular, we observe an electron band located above the Fermi level before doping that shares similarities with a small three-dimensional pocket observed in the cousin, heavily-electron-doped KFe??xSe? compound.

  15. Residual and nitrogen doping of homoepitaxial nonpolar m-plane ZnO films grown by molecular beam epitaxy

    SciTech Connect (OSTI)

    Taienoff, D.; Deparis, C.; Teisseire, M.; Morhain, C. [Centre de Recherche sur l'Hetero-Epitaxie et ses Applications, Centre National de la Recherche Scientifique (CRHEA-CNRS), Rue B. Gregory, F-06560 Valbonne Sophia Antipolis (France); Al-Khalfioui, M.; Vinter, B.; Chauveau, J.-M. [Centre de Recherche sur l'Hetero-Epitaxie et ses Applications, Centre National de la Recherche Scientifique (CRHEA-CNRS), Rue B. Gregory, F-06560 Valbonne Sophia Antipolis (France); Universite de Nice Sophia Antipolis, Parc Valrose F-06103 Nice (France)

    2011-03-28T23:59:59.000Z

    We report the homoepitaxial growth by molecular beam epitaxy of high quality nonpolar m-plane ZnO and ZnO:N films over a large temperature range. The nonintentionally doped ZnO layers exhibit a residual doping as low as {approx}10{sup 14} cm{sup -3}. Despite an effective incorporation of nitrogen, p-type doping was not achieved, ZnO:N films becoming insulating. The high purity of the layers and their low residual n-type doping evidence compensation mechanisms in ZnO:N films.

  16. Electrochemical properties of lithium polymer batteries with doped polyaniline as cathode material

    SciTech Connect (OSTI)

    Manuel, James [Department of Chemical and Biological Engineering and Research Institute for Green Energy Convergence Technology, Gyeongsang National University, 900, Gajwa-dong, Jinju 660-701 (Korea, Republic of)] [Department of Chemical and Biological Engineering and Research Institute for Green Energy Convergence Technology, Gyeongsang National University, 900, Gajwa-dong, Jinju 660-701 (Korea, Republic of); Kim, Jae-Kwang; Matic, Aleksandar; Jacobsson, Per [Department of Applied Physics, Chalmers University of Technology, SE-41296 Göteborg (Sweden)] [Department of Applied Physics, Chalmers University of Technology, SE-41296 Göteborg (Sweden); Chauhan, Ghanshyam S. [Department of Chemistry, Himachal Pradesh University, Shimla 171005 (India)] [Department of Chemistry, Himachal Pradesh University, Shimla 171005 (India); Ha, Jong Keun; Cho, Kwon-Koo [Department of Materials Science and Engineering, Gyeongsang National University, 900, Gajwa-dong, Jinju 660-701 (Korea, Republic of)] [Department of Materials Science and Engineering, Gyeongsang National University, 900, Gajwa-dong, Jinju 660-701 (Korea, Republic of); Ahn, Jou-Hyeon, E-mail: jhahn@gnu.ac.kr [Department of Chemical and Biological Engineering and Research Institute for Green Energy Convergence Technology, Gyeongsang National University, 900, Gajwa-dong, Jinju 660-701 (Korea, Republic of)] [Department of Chemical and Biological Engineering and Research Institute for Green Energy Convergence Technology, Gyeongsang National University, 900, Gajwa-dong, Jinju 660-701 (Korea, Republic of)

    2012-10-15T23:59:59.000Z

    Graphical abstract: -- Abstract: Polyaniline (PANI) was doped with different lithium salts such as LiPF{sub 6} and LiClO{sub 4} and evaluated as cathode-active material for application in room-temperature lithium batteries. The doped PANI was characterized by FTIR and XPS measurements. In the FTIR spectra, the characteristic peaks of PANI are shifted to lower bands as a consequence of doping, and it is more shifted in the case of PANI doped with LiPF{sub 6}. The cathodes prepared using PANI doped with LiPF{sub 6} and LiClO{sub 4} delivered initial discharge capacities of 125 mAh g{sup ?1} and 112 mAh g{sup ?1} and stable reversible capacities of 114 mAh g{sup ?1} and 81 mAh g{sup ?1}, respectively, after 10 charge–discharge cycles. The cells were also tested using polymer electrolyte, which delivered highest discharge capacities of 142.6 mAh g{sup ?1} and 140 mAh g{sup ?1} and stable reversible capacities of 117 mAh g{sup ?1} and 122 mAh g{sup ?1} for PANI-LiPF{sub 6} and PANI-LiClO{sub 4}, respectively, after 10 cycles. The cathode prepared with LiPF{sub 6} doped PANI shows better cycling performance and stability as compared to the cathode prepared with LiClO{sub 4} doped PANI using both liquid and polymer electrolytes.

  17. Effect of carrier doping on the formation and collapse of magnetic polarons in lightly hole-doped La1-xSrxCoO3

    SciTech Connect (OSTI)

    Podlesnyak, Andrey A [ORNL; Ehlers, Georg [ORNL; Frontzek, Matthias D [ORNL; Sefat, A. S. [Oak Ridge National Laboratory (ORNL); Furrer, Albert [Laboratory for Neutron Scattering ETHZ & PSI; Straessle, Thierry [Laboratory for Neutron Scattering ETHZ & PSI; Pomjakushina, Ekaterina [Paul Scherrer Institut, Villigen, Switzerland; Conder, Kazimierz [Paul Scherrer Institut, Villigen, Switzerland; Demmel, F. [ISIS Facility, Rutherford Appleton Laboratory; Khomskii, D. I. [Universitat zu Koln, Koln, Germany

    2011-01-01T23:59:59.000Z

    We investigate the doping dependence of the nanoscale electronic and magnetic inhomogeneities in the hole-doping range 0.002 < x < 0.1 of cobalt based perovskites, La{sub 1-x}Sr{sub x}CoO{sub 3}. Using single-crystal inelastic neutron scattering and magnetization measurements we show that the lightly doped system exhibits magnetoelectronic phase separation in the form of spin-state polarons. Higher hole doping leads to a decay of spin-state polarons in favor of larger scale magnetic clusters, due to competing ferromagnetic correlations of Co{sup 3+} ions which are formed by neighboring polarons. The present data give evidence for two regimes of magnetoelectronic phase separation in this system: (i) x {approx}< 0.05, dominated by ferromagnetic intrapolaron interactions, and (ii) x {approx}> 0.05, dominated by Co{sup 3+}-Co{sup 3+} intracluster interactions. Our conclusions are in good agreement with a recently proposed model of the phase separation in cobalt perovskites.

  18. DEVELOPMENT OF DOPED NANOPOROUS CARBONS FOR HYDROGEN STORAGE

    SciTech Connect (OSTI)

    Angela D. Lueking; Qixiu Li; John V. Badding; Dania Fonseca; Humerto Gutierrez; Apurba Sakti; Kofi Adu; Michael Schimmel

    2010-03-31T23:59:59.000Z

    Hydrogen storage materials based on the hydrogen spillover mechanism onto metal-doped nanoporous carbons are studied, in an effort to develop materials that store appreciable hydrogen at ambient temperatures and moderate pressures. We demonstrate that oxidation of the carbon surface can significantly increase the hydrogen uptake of these materials, primarily at low pressure. Trace water present in the system plays a role in the development of active sites, and may further be used as a strategy to increase uptake. Increased surface density of oxygen groups led to a significant enhancement of hydrogen spillover at pressures less than 100 milibar. At 300K, the hydrogen uptake was up to 1.1 wt. % at 100 mbar and increased to 1.4 wt. % at 20 bar. However, only 0.4 wt% of this was desorbable via a pressure reduction at room temperature, and the high lowpressure hydrogen uptake was found only when trace water was present during pretreatment. Although far from DOE hydrogen storage targets, storage at ambient temperature has significant practical advantages oner cryogenic physical adsorbents. The role of trace water in surface modification has significant implications for reproducibility in the field. High-pressure in situ characterization of ideal carbon surfaces in hydrogen suggests re-hybridization is not likely under conditions of practical interest. Advanced characterization is used to probe carbon-hydrogen-metal interactions in a number of systems and new carbon materials have been developed.

  19. Method of preparing doped oxide catalysts for lean NOx exhaust

    DOE Patents [OSTI]

    Park, Paul W.

    2004-03-09T23:59:59.000Z

    The lean NOx catalyst includes a substrate, an oxide support material, preferably .gamma.-alumina deposited on the substrate and a metal or metal oxide promoter or dopant introduced into the oxide support material. The metal promoters or dopants are selected from the group consisting of indium, gallium, tin, silver, germanium, gold, nickel, cobalt, copper, iron, manganese, molybdenum, chromium cerium, and vanadium, and oxides thereof, and any combinations thereof. The .gamma.-alumina preferably has a pore volume of from about 0.5 to about 2.0 cc/g; a surface area of between 80 and 350 m.sup.2 /g; an average pore size diameter of between about 3 to 30 nm; and an impurity level of less than or equal to about 0.2 weight percent. In a preferred embodiment the .gamma.-alumina is prepared by a sol-gel method, with the metal doping of the .gamma.-alumina preferably accomplished using an incipient wetness impregnation technique.

  20. Crystallizing hard-sphere glasses by doping with active particles

    E-Print Network [OSTI]

    Ran Ni; Martien A. Cohen Stuart; Marjolein Dijkstra; Peter G. Bolhuis

    2014-08-25T23:59:59.000Z

    Crystallization and vitrification are two different routes to form a solid. Normally these two processes suppress each other, with the glass transition preventing crystallization at high density (or low temperature). This is even true for systems of colloidal hard spheres, which are commonly used as building blocks for novel functional materials with potential applications, e.g. photonic crystals. By performing Brownian dynamics simulations of glassy systems consisting of mixtures of active and passive hard spheres, we show that the crystallization of such hard-sphere glasses can be dramatically promoted by doping the system with small amounts of active particles. Surprisingly, even hard-sphere glasses of packing fraction up to $\\phi = 0.635$ crystallize, which is around $0.5\\%$ below the random close packing at $\\phi \\simeq 0.64$. Our results suggest a novel way of fabricating crystalline materials from (colloidal) glasses. This is particularly important for materials that get easily kinetically trapped in glassy states, and crystal nucleation hardly occurs.

  1. Impurity-doped optical shock, detonation and damage location sensor

    DOE Patents [OSTI]

    Weiss, J.D.

    1995-02-07T23:59:59.000Z

    A shock, detonation, and damage location sensor providing continuous fiber-optic means of measuring shock speed and damage location, and could be designed through proper cabling to have virtually any desired crush pressure. The sensor has one or a plurality of parallel multimode optical fibers, or a singlemode fiber core, surrounded by an elongated cladding, doped along their entire length with impurities to fluoresce in response to light at a different wavelength entering one end of the fiber(s). The length of a fiber would be continuously shorted as it is progressively destroyed by a shock wave traveling parallel to its axis. The resulting backscattered and shifted light would eventually enter a detector and be converted into a proportional electrical signals which would be evaluated to determine shock velocity and damage location. The corresponding reduction in output, because of the shortening of the optical fibers, is used as it is received to determine the velocity and position of the shock front as a function of time. As a damage location sensor the sensor fiber cracks along with the structure to which it is mounted. The size of the resulting drop in detector output is indicative of the location of the crack. 8 figs.

  2. Impurity-doped optical shock, detonation and damage location sensor

    DOE Patents [OSTI]

    Weiss, Jonathan D. (Albuquerque, NM)

    1995-01-01T23:59:59.000Z

    A shock, detonation, and damage location sensor providing continuous fiber-optic means of measuring shock speed and damage location, and could be designed through proper cabling to have virtually any desired crush pressure. The sensor has one or a plurality of parallel multimode optical fibers, or a singlemode fiber core, surrounded by an elongated cladding, doped along their entire length with impurities to fluoresce in response to light at a different wavelength entering one end of the fiber(s). The length of a fiber would be continuously shorted as it is progressively destroyed by a shock wave traveling parallel to its axis. The resulting backscattered and shifted light would eventually enter a detector and be converted into a proportional electrical signals which would be evaluated to determine shock velocity and damage location. The corresponding reduction in output, because of the shortening of the optical fibers, is used as it is received to determine the velocity and position of the shock front as a function of time. As a damage location sensor the sensor fiber cracks along with the structure to which it is mounted. The size of the resulting drop in detector output is indicative of the location of the crack.

  3. Refractive index of erbium doped GaN thin films

    SciTech Connect (OSTI)

    Alajlouni, S.; Sun, Z. Y.; Li, J.; Lin, J. Y.; Jiang, H. X., E-mail: hx.jiang@ttu.edu [Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, Texas 79409 (United States); Zavada, J. M. [Department of Electrical and Computer Engineering, Polytechnic Institute of New York University, Brooklyn, New York 11201 (United States)

    2014-08-25T23:59:59.000Z

    GaN is an excellent host for erbium (Er) to provide optical emission in the technologically important as well as eye-safe 1540?nm wavelength window. Er doped GaN (GaN:Er) epilayers were synthesized on c-plane sapphire substrates using metal organic chemical vapor deposition. By employing a pulsed growth scheme, the crystalline quality of GaN:Er epilayers was significantly improved over those obtained by conventional growth method of continuous flow of reaction precursors. X-ray diffraction rocking curve linewidths of less than 300?arc sec were achieved for the GaN (0002) diffraction peak, which is comparable to the typical results of undoped high quality GaN epilayers and represents a major improvement over previously reported results for GaN:Er. Spectroscopic ellipsometry was used to determine the refractive index of the GaN:Er epilayers in the 1540?nm wavelength window and a linear dependence on Er concentration was found. The observed refractive index increase with Er incorporation and the improved crystalline quality of the GaN:Er epilayers indicate that low loss GaN:Er optical waveguiding structures are feasible.

  4. Nitrogen doping of chemical vapor deposition grown graphene on 4H-SiC (0001)

    SciTech Connect (OSTI)

    Urban, J. M.; Binder, J.; Wysmo?ek, A. [Faculty of Physics, University of Warsaw, ul. Ho?a 69, 00-681 Warsaw (Poland); D?browski, P.; Strupi?ski, W. [Institute of Electronic Materials Technology, ul. Wólczy?ska 133, 01-919 Warsaw (Poland); Kopciuszy?ski, M.; Ja?ochowski, M. [Institute of Physics, Maria Curie-Sk?odowska University, pl. M. Curie-Sk?odowskiej 1, 20-031 Lublin (Poland); Klusek, Z. [Faculty of Physics and Applied Informatics, University of ?ód?, ul. Pomorska 149/153, 90-236 ?ód? (Poland); Baranowski, J. M. [Faculty of Physics, University of Warsaw, ul. Ho?a 69, 00-681 Warsaw (Poland); Institute of Electronic Materials Technology, ul. Wólczy?ska 133, 01-919 Warsaw (Poland)

    2014-06-21T23:59:59.000Z

    We present optical, electrical, and structural properties of nitrogen-doped graphene grown on the Si face of 4H-SiC (0001) by chemical vapor deposition method using propane as the carbon precursor and N{sub 2} as the nitrogen source. The incorporation of nitrogen in the carbon lattice was confirmed by X-ray photoelectron spectroscopy. Angle-resolved photoemission spectroscopy shows carrier behavior characteristic for massless Dirac fermions and confirms the presence of a graphene monolayer in the investigated nitrogen-doped samples. The structural and electronic properties of the material were investigated by Raman spectroscopy. A systematical analysis of the graphene Raman spectra, including D, G, and 2D bands, was performed. In the case of nitrogen-doped samples, an electron concentration on the order of 5–10 × 10{sup 12}?cm{sup ?2} was estimated based upon Raman and Hall effect measurements and no clear dependence of the carrier concentration on nitrogen concentration used during growth was observed. This high electron concentration can be interpreted as both due to the presence of nitrogen in graphitic-like positions of the graphene lattice as well as to the interaction with the substrate. A greater intensity of the Raman D band and increased inhomogeneity, as well as decreased electron mobility, observed for nitrogen-doped samples, indicate the formation of defects and a modification of the growth process induced by nitrogen doping.

  5. Improved gas sensing and dielectric properties of Fe doped hydroxyapatite thick films: Effect of molar concentrations

    SciTech Connect (OSTI)

    Mene, Ravindra U. [PDEA's, Annasaheb Waghire College of Science, Arts and Commerce, Otur 412409, M.S. (India); School of Physical Sciences, Swami Ramanand Teerth Marathwada University, Nanded 431606, M.S. (India); Mahabole, Megha P. [School of Physical Sciences, Swami Ramanand Teerth Marathwada University, Nanded 431606, M.S. (India); Mohite, K.C. [Haribhai. V. Desai College, Pune 411002, M.S. (India); Khairnar, Rajendra S., E-mail: rskhairnarsps@gmail.com [School of Physical Sciences, Swami Ramanand Teerth Marathwada University, Nanded 431606, M.S. (India)

    2014-02-01T23:59:59.000Z

    Highlights: • We report improved gas sensing and dielectric characteristics of Fe ion exchanged HAp films. • Fe doped HAp film shows maximum gas response at relatively lower temperature. • Response and gas uptake capacity of sensors is improved for appropriate amount of Fe ions in HAp matrix. • Fe-HAp films exhibit remarkable improvement in dielectric properties compared to pure HAp. • Fe doped HAp films show significant improvement in gas sensing as well as in dielectric properties. - Abstract: In the present work Fe doped hydroxyapatite (Fe-HAp) thick films has been successfully utilized to improve the gas sensing as well as its dielectric properties. Initially, HAp nano powder is synthesized by chemical precipitation process and later on Fe ions are doped in HAp by ion exchange process. Structural and morphological modifications are observed by means of X-ray diffraction and scanning electron microscopy analysis. The sensing parameters such as operating temperature, response/recovery time and gas uptake capacity are experimentally determined. The Fe-HAp (0.05 M) film shows improved CO and CO{sub 2} gas sensing capacity at lower operating temperature compared to pure HAp. Moreover, variation of dielectric constant and dielectric loss for pure and Fe-HAp thick films are studied as a function of frequency in the range of 10 Hz–1 MHz. The study reveals that Fe doped HAp thick films improve the sensing and dielectric characteristics as compared to pure HAp.

  6. Formation of Carbon Nanostructures in Cobalt- and Nickel-Doped Carbon Aerogels

    SciTech Connect (OSTI)

    Fu, R; Baumann, T F; Cronin, S; Dresselhaus, G; Dresselhaus, M; Satcher, Jr., J H

    2004-11-09T23:59:59.000Z

    We have prepared carbon aerogels (CAs) doped with cobalt or nickel through sol-gel polymerization of formaldehyde with the potassium salt of 2,4-dihydroxybenzoic acid, followed by ion-exchange with M(NO{sub 3}){sub 2} (where M = Co{sup 2+} or Ni{sup 2+}), supercritical drying with liquid CO{sub 2} and carbonization at temperatures between 400 C and 1050 C under an N{sub 2} atmosphere. The nanostructures of these metal-doped carbon aerogels were characterized by elemental analysis, nitrogen adsorption, high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). Metallic nickel and cobalt nanoparticles are generated during the carbonization process at about 400 C and 450 C, respectively, forming nanoparticles that are {approx}4 nm in diameter. The sizes and size dispersion of the metal particles increase with increasing carbonization temperatures for both materials. The carbon frameworks of the Ni- and Co-doped aerogels carbonized below 600 C mainly consist of interconnected carbon particles with a size of 15 to 30 nm. When the samples are pyrolyzed at 1050 C, the growth of graphitic nanoribbons with different curvatures is observed in the Ni and Co-doped carbon aerogel materials. The distance of graphite layers in the nanoribbons is about 0.38 nm. These metal-doped CAs retain the overall open cell structure of metal-free CAs, exhibiting high surface areas and pore diameters in the micro and mesoporic region.

  7. D{sup 0} magnetism in Ca doped narrow carbon nanotubes: First principle chirality effect study

    SciTech Connect (OSTI)

    Hajiheidari, F.; Khoshnevisan, B., E-mail: b.khosh@kashanu.ac.ir [Faculty of Physics, University of Kashan, Kashan (Iran, Islamic Republic of); Hashemifar, S. J. [Faculty of Physics, Isfahan University of technology, 84156-83111 Isfahan (Iran, Islamic Republic of)

    2014-06-21T23:59:59.000Z

    Curvature has always had crucial effects on the physical properties of narrow carbon nanotubes (CNTs) and here spin-polarized density functional calculations were employed to study electronic and magnetic properties of calcium-decorated narrow (5,5) and (9,0)CNTs with close diameters (?7?Å) and different chiralities. Our results showed that chirality had great impact on the electronic structure and magnetization of the doped CNTs. In addition, internally or externally doping of the calcium atoms was studied comparatively and although for the (9,0)CNT the internal doping was the most stable configuration, which involves a novel kind of spin-polarization originated from Ca-4s electrons, but for the (5,5)tube the external doping was the most stable one without any spin-polarization. On the other hand, calcium doping in the center of the (5,5)CNT was an endothermic process and led to the spin-polarization of unoccupied Ca-3d orbitals via direct exchange interaction between adjacent Ca atoms. In the considered systems, the existence of magnetization in the absence of any transition-metal elements was an example of valuable d{sup 0} magnetism title.

  8. Zinc Doping in Cosubstituted In2-2xSnxZnxO3-A. Ambrosini, S. Malo, and K. R. Poeppelmeier*

    E-Print Network [OSTI]

    Poeppelmeier, Kenneth R.

    applications such as solar cells and flat panel and liquid crystal displays. Sn-doped indium oxide (ITO

  9. Doping dependence of the superconducting gap in Bi2Sr2CaCu2O8 K. C. Hewitt* and J. C. Irwin

    E-Print Network [OSTI]

    Hewitt, Kevin

    Doping dependence of the superconducting gap in Bi2Sr2CaCu2O8¿ K. C. Hewitt* and J. C. Irwin.23) were studied to investigate the effects of doping on the symmetry and magnitude of the superconducting). The latter observations have led us to conclude that the doping dependence of the superconducting gap

  10. Thermoelectric and micro-Raman measurements of carrier density and mobility in heavily Si-doped GaN wires

    E-Print Network [OSTI]

    Boyer, Edmond

    Thermoelectric and micro-Raman measurements of carrier density and mobility in heavily Si-doped Ga (Received 19 July 2013; accepted 28 October 2013; published online 11 November 2013) Combined thermoelectric epitaxy (MOVPE). These highly conductive Si-doped GaN wires were studied by means of thermoelectrical

  11. Hydrogen-doped cubic diamond and the crystal structure of n-diamond Bin Wen a,b,

    E-Print Network [OSTI]

    Melnik, Roderick

    Hydrogen-doped cubic diamond and the crystal structure of n-diamond Bin Wen a,b, , Roderick Melnik. In particular, hydrogen concen- tration dependent elastic constants and lattice parameters for the H-doped diamond have been analyzed. Our results indicate that when the hydrogen concentration is less than 19 at

  12. Decorating anode with bamboo-like nitrogen-doped carbon nanotubes for microbial Suqin Ci a,c

    E-Print Network [OSTI]

    Decorating anode with bamboo-like nitrogen-doped carbon nanotubes for microbial fuel cells Suqin Ci, Nanchang 330063, PR China b Department of Mechanical, University of Wisconsin--Milwaukee, 3200 North Cramer November 2011 Available online 20 November 2011 Keywords: Carbon nanotubes Nitrogen doping Anode Microbial

  13. Journal of Electronic Materials, Vol. 19, No, 4, 1990 Carbon Tetrachloride Doped AIxGa_xAS

    E-Print Network [OSTI]

    Cunningham, Brian

    Journal of Electronic Materials, Vol. 19, No, 4, 1990 Carbon Tetrachloride Doped AIx been shown to be a suitable carbon doping source for obtaining p-type GaAs grown by metalorganic chemical vapor deposition (MOCVD) with carbon acceptor concentrations in excess of 1 x 1019cm-3

  14. Raman and conductivity studies of boron-doped microcrystalline diamond, facetted nanocrystalline diamond and cauliflower diamond films

    E-Print Network [OSTI]

    Bristol, University of

    -like conductivity. A complication is that polycrystalline boron-doped CVD diamond films possess grain boundariesRaman and conductivity studies of boron-doped microcrystalline diamond, facetted nanocrystalline diamond and cauliflower diamond films P.W. May a,, W.J. Ludlow a , M. Hannaway a , P.J. Heard b , J

  15. Influence of Nitrogen Doping on the Defect Formation and Surface Properties of TiO2 Rutile and Anatase

    E-Print Network [OSTI]

    Diebold, Ulrike

    Influence of Nitrogen Doping on the Defect Formation and Surface Properties of TiO2 Rutile, New Orleans, Louisiana 70118, USA (Received 25 July 2005; published 20 January 2006) Nitrogen doping numbers: 68.35.ÿp, 81.05.Je, 82.65.+r Titanium dioxide (TiO2) is a good photocatalyst for the remediation

  16. H.sub.2O doped WO.sub.3, ultra-fast, high-sensitivity hydrogen sensors

    DOE Patents [OSTI]

    Liu, Ping (Denver, CO); Tracy, C. Edwin (Golden, CO); Pitts, J. Roland (Lakewood, CO); Lee, Se-Hee (Lakewood, CO)

    2011-03-22T23:59:59.000Z

    An ultra-fast response, high sensitivity structure for optical detection of low concentrations of hydrogen gas, comprising: a substrate; a water-doped WO.sub.3 layer coated on the substrate; and a palladium layer coated on the water-doped WO.sub.3 layer.

  17. Dopant Ion Size and Electronic Structure Effects on Transparent Conducting Oxides. Sc-Doped CdO Thin Films

    E-Print Network [OSTI]

    Medvedeva, Julia E.

    O Thin Films Grown by MOCVD Shu Jin,, Yu Yang,, Julia E. Medvedeva,,§ John R. Ireland,| Andrew W. Metz-doped CdO (CSO) thin films have been grown on both amorphous glass and single-crystal MgO(100) substrates) at a Sc doping level of 1.8 atom %. The CSO thin films exhibit an average transmittance >80

  18. Structure and hydrogen dynamics of pure and Ti-doped sodium alanate Jorge iguez,1,2

    E-Print Network [OSTI]

    Yildirim, Taner

    Structure and hydrogen dynamics of pure and Ti-doped sodium alanate Jorge Íñiguez,1,2 T. Yildirim,1, Honolulu, Hawaii 96822, USA (Received 2 June 2004; published 3 August 2004) We have studied the structure, energetics, and dynamics of pure and Ti-doped sodium alanate NaAlH4 , focusing on the possibility

  19. PHYSICAL REVIEW B 86, 075207 (2012) Optical signature of Mg-doped GaN: Transfer processes

    E-Print Network [OSTI]

    Nabben, Reinhard

    2012-01-01T23:59:59.000Z

    PHYSICAL REVIEW B 86, 075207 (2012) Optical signature of Mg-doped GaN: Transfer processes G; published 23 August 2012) Mg doping of high quality, metal organic chemical vapor deposition grown GaN films GaN:Mg grown on sapphire substrates and identify two Mg related acceptor states, one additional

  20. TOWARDS AN ER-DOPED SI NANOCRYSTAL SENSITIZED WAVEGUIDE LASER THE THIN LINE BETWEEN GAIN AND LOSS

    E-Print Network [OSTI]

    Kik, Pieter

    and waveguide. If the pump laser could somehow be eliminated from this scheme, the fabrication of low-cost SiTOWARDS AN ER-DOPED SI NANOCRYSTAL SENSITIZED WAVEGUIDE LASER ­ THE THIN LINE BETWEEN GAIN AND LOSS-doped SiO2, a composite material that can potentially be fabricated using a VLSI compatible process