liu.seSearch for publications in DiVA
Change search
Refine search result
1234567 1 - 50 of 398
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1. Arnaudov, B.
    et al.
    Paskov, Plamen
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Harati Zadeh, Hamid
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Holtz, Per-Olof
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Kamiyama, S.
    Iwaya, M.
    Amano, H.
    Akasaki, I.
    Radiative recombination mechanism in highly modulation doped GaN/AlGaN multiple quantum wells2006In: Physica Status Solidi. C, Current topics in solid state physics, ISSN 1610-1634, E-ISSN 1610-1642, Vol. 6, p. 1888-1891Article in journal (Refereed)
  • 2. Arnaudov, B.
    et al.
    Paskova, T.
    Evtimova, S.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Lu, H.
    Schaff, W.J.
    Electron concentration and mobility profiles in InN layers grown by MBE2006Article in journal (Refereed)
    Abstract [en]

    We have studied depth distributions of the electrical parameters in MBE grown InN films with two types of AlN and GaN buffers. Using independently determined Hall effect electron concentration and mobility profiles, as well as electron concentration profile by photoluminescence measurements, we model the real depth profile of carrier mobility, assuming graded inhomogeneity of the sample. The obtained profiles follow power dependences of the same order for layers grown on the two buffers with a small difference in the function coefficients attributed to a contribution of the interface charge in layers grown on AlN buffers. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA.

  • 3. Arnaudov, B
    et al.
    Paskova, Tanja
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Evtimova, S
    Heuken, M
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Hall effect data analysis of GaN n(+)n structures2002In: Physica status solidi. B, Basic research, ISSN 0370-1972, E-ISSN 1521-3951, Vol. 234, no 3, p. 872-876Article in journal (Refereed)
    Abstract [en]

    We develop a model for analysis of Hall effect data of GaN structures composed of sublayers with different thicknesses and contacts placed on the top surface, We analysed the contributions of the conductivity of every sublayer of a planar sample taking into account the fact that the sample sublayers are partially connected in parallel to each other by series resistances formed in areas lying below the contacts from the upper layer. Correction factors, which reduce the contribution of the underlying layers to the measured whole sample conductivity, are obtained from the equations relevant to the respective equivalent circuit.

  • 4. Arnaudov, B
    et al.
    Paskova, Tanja
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Evtimova, S
    Valcheva, E
    Heuken, M
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Multilayer model for Hall effect data analysis of semiconductor structures with step-changed conductivity2003In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 67, no 4Article in journal (Refereed)
    Abstract [en]

    We present a multilayer model for analysis of Hall effect data of semiconductor structures composed of sublayers with different thicknesses and contacts placed on the top surface. Based on the circuit theory we analyze the contributions of the conductivity of every sublayer and derive general expressions for the conductivity and carrier mobility of a multilayer planar sample. The circuit analysis is performed taking into account the fact that the sample sublayers are partially connected in parallel to each other by series resistances formed in areas lying below the contacts from each upper layer. In order to solve the inverse problem of determining the electrical parameters of one of the sublayers, a procedure for analysis of the Hall effect data is proposed. The model is simplified for a structure composed of two layers with the same type of conductivity, and is used to determine the electrical parameters of GaN films grown on relatively thick GaN buffers.

  • 5.
    Arnaudov, B
    et al.
    Faculty of Physics, Sofia University, Sofia, Bulgaria.
    Paskova, Tanja
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Goldys, EM
    Semiconductor Science and Technology Laboratories, Macquarie University, Sydney, Australia.
    Evtimova, S
    Faculty of Physics, Sofia University, Sofia, Bulgaria.
    Monemar, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Modeling of the free-electron recombination band in emission spectra of highly conducting n-GaN2001In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 64, no 4Article in journal (Refereed)
    Abstract [en]

    We simulate the spectral distribution of the free-electron recombination band in optical emission spectra of GaN with a free-carrier concentration in the range of 5 x 10(17)-1 x 10(20) cm(-3). The influence of several factors, such as nonparabolicity, electron-electron interaction. and electron-impurity interaction on both the spectral and energy position and the effective gap narrowing are taken into account. The calculated properties of the free-electron-related emission bands are used to interpret the experimental photoluminescence and cathodoluminescence spectra of GaN epitaxial layers.

  • 6. Arnaudov, B.
    et al.
    Paskova, Tanja
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Paskov, Plamen
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Magnusson, Björn
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Lu, H.
    Schaff, W.J.
    On the nature of the near bandedge luminescence of InN epitaxial layers2005In: AIP Conference Proceedings, ISSN 0094-243X, E-ISSN 1551-7616, Vol. 772, p. 285-286Article in journal (Refereed)
  • 7. Arnaudov, B
    et al.
    Paskova, Tanja
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Paskov, Plamen
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Magnusson, Björn
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Valcheva, E
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Lu, H
    Schaff, WJ
    Amano, H
    Akasaki, I
    Energy position of near-band-edge emission spectra of InN epitaxial layers with different doping levels2004In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 69, no 11Article in journal (Refereed)
    Abstract [en]

    We studied the shape and energy position of near-band-edge photoluminescence spectra of InN epitaxial layers with different doping levels. We found that the experimental spectra of InN layers with moderate doping level can be nicely interpreted in the frames of the "free-to-bound" recombination model in degenerate semiconductors. For carrier concentrations above n>5x10(18) cm(-3) the emission spectra can also be modeled satisfactorily, but a contribution due to a pushing up of nonequilibrium holes over the thermal delocalization level in the valence band tails should be considered in the model. The emission spectra of samples with low doping level were instead explained as a recombination from the bottom of the conduction band to a shallow acceptor assuming the same value of the acceptor binding energy estimated from the spectra of highly doped samples. Analyzing the shape and energy position of the free-electron recombination spectra we determined the carrier concentrations responsible for the emissions and found that the fundamental band gap energy of InN is E-g=692+/-2 meV for an effective mass at the conduction-band minimum m(n0)=0.042m(0).

  • 8.
    Arnaudov, B.
    et al.
    Faculty of Physics, Sofia University, 5 J. Bourchier Blvd, 1164 Sofia, Bulgaria.
    Paskova, Tanja
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Paskov, Plamen
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Magnusson, Björn
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Valcheva, E.
    Faculty of Physics, Sofia University, 5 J. Bourchier Blvd, 1164 Sofia, Bulgaria.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Lu, H.
    Department of Electrical Engineering, Cornell University, Ithaka, NY 14583, United States.
    Schaff, W.J.
    Department of Electrical Engineering, Cornell University, Ithaka, NY 14583, United States.
    Amano, H.
    Department of Electrical Engineering, Meijo University, I-501 Shiogamaguchi, Tempaku-ku, Nagoia 468, Japan.
    Akasaki, I.
    Department of Electrical Engineering, Meijo University, I-501 Shiogamaguchi, Tempaku-ku, Nagoia 468, Japan.
    Free-to-bound radiative recombination in highly conducting InN epitaxial layers2004In: Superlattices and Microstructures, ISSN 0749-6036, E-ISSN 1096-3677, Vol. 36, no 4-6, p. 563-571Article in journal (Refereed)
    Abstract [en]

    We present a theoretical simulation of near-band-edge emission spectra of highly conducting n-InN assuming the model of 'free-to-bound' radiative recombination (FBRR) of degenerate electrons from the conduction band with nonequilibrium holes located in the valence band tails. We also study experimental photoluminescence (PL) spectra of highly conducting InN epitaxial layers grown by MBE and MOVPE with electron concentrations in the range (7.7 × 1017-6 × 1018) cm-3 and find that the energy positions and shape of the spectra depend on the impurity concentration. By modeling the experimental PL spectra of the InN layers we show that spectra can be nicely interpreted in the framework of the FBRR model with specific peculiarities for different doping levels. Analyzing simultaneously the shape and energy position of the InN emission spectra we determine the fundamental bandgap energy of InN to vary between Eg = 692 meV for effective mass mn0 = 0.042m0 and Eg =710 meV for mn0 = 0.1m0. © 2004 Elsevier Ltd. All rights reserved.

  • 9.
    Arnaudov, B.
    et al.
    Faculty of Physics, Sofia University, 1164 Sofia, Bulgaria.
    Paskova, Tanja
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Valassiades, O.
    Aristoteles Univ. of Thessaloniki, Solid State Physics Section, 54124 Thessaloniki, Greece.
    Paskov, Plamen
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Evtimova, S.
    Faculty of Physics, Sofia University, 1164 Sofia, Bulgaria.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Heuken, M.
    AIXTRON AG, D-52072 Aachen, Germany.
    Magnetic-field-induced localization of electrons in InGaN/GaN multiple quantum wells2003In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 83, no 13, p. 2590-2592Article in journal (Refereed)
    Abstract [en]

    A study was performed on the magnetic-field-induced localization of electrons in InGaN/GaN multiple quantum wells (MQW). A stepwise behavior of both the Hall coefficient and magnetoresistivity was observed. The peculiarities were explained by a magnetic-field-induced localization of electrons in a two-dimensional (2D) potential relief of the InGaN MQW.

  • 10.
    Arwin, Hans
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Optics .
    Darakchieva, Vanya
    Linköping University, Department of Physics, Chemistry and Biology.
    Paskova, Tanja
    Linköping University, Department of Physics, Chemistry and Biology.
    Paskov, Plamen
    Linköping University, Department of Physics, Chemistry and Biology.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Schubert, Mattias
    Department of Electrical Engineering University of Nebraska.
    Figge, S
    Hommel, D
    Haskell, B A
    Fini, P T
    Nakamura, S
    Assessment of phonon mode characteristics via infrared spectroscopic ellipsometry on a-plane GaN2005In: ICSN-6,2005, 2005Conference paper (Other academic)
  • 11.
    Ashkenov, N.
    et al.
    Universität Leipzig, Fak. F. Phys. and Geowissenschaften, Inst. F. Experimentelle Physik II, Linnéstrasse 5, 04103 Leipzig, Germany.
    Mbenkum, B.N.
    Universität Leipzig, Fak. F. Phys. and Geowissenschaften, Inst. F. Experimentelle Physik II, Linnéstrasse 5, 04103 Leipzig, Germany.
    Bundesmann, C.
    Universität Leipzig, Fak. F. Phys. and Geowissenschaften, Inst. F. Experimentelle Physik II, Linnéstrasse 5, 04103 Leipzig, Germany.
    Riede, V.
    Universität Leipzig, Fak. F. Phys. and Geowissenschaften, Inst. F. Experimentelle Physik II, Linnéstrasse 5, 04103 Leipzig, Germany.
    Lorenz, M.
    Universität Leipzig, Fak. F. Phys. and Geowissenschaften, Inst. F. Experimentelle Physik II, Linnéstrasse 5, 04103 Leipzig, Germany.
    Spemann, D.
    Universität Leipzig, Fak. F. Phys. and Geowissenschaften, Inst. F. Experimentelle Physik II, Linnéstrasse 5, 04103 Leipzig, Germany.
    Kaidashev, E.M.
    Universität Leipzig, Fak. F. Phys. and Geowissenschaften, Inst. F. Experimentelle Physik II, Linnéstrasse 5, 04103 Leipzig, Germany, Rostov State University, Mech./Appl. Math. Research Institute, 200/1 Stachky Avenue, Rostov-on-Don 344090, Russian Federation.
    Kasic, A.
    Universität Leipzig, Fak. F. Phys. and Geowissenschaften, Inst. F. Experimentelle Physik II, Linnéstrasse 5, 04103 Leipzig, Germany.
    Schubert, M.
    Universität Leipzig, Fak. F. Phys. and Geowissenschaften, Inst. F. Experimentelle Physik II, Linnéstrasse 5, 04103 Leipzig, Germany.
    Grundmann, M.
    Universität Leipzig, Fak. F. Phys. and Geowissenschaften, Inst. F. Experimentelle Physik II, Linnéstrasse 5, 04103 Leipzig, Germany.
    Wagner, G.
    Inst. F. Nichtklassische Chem. e.V., Universität Leipzig, Permoserstraße 15, 04318 Leipzig, Germany.
    Neumann, H.
    Inst. F. O. e.V., Permoserstrasse 15, 04303 Leipzig, Germany.
    Darakchieva, Vanya
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Arwin, Hans
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Optics .
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Infrared dielectric functions and phonon modes of high-quality ZnO films2003In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 93, no 1, p. 126-133Article in journal (Refereed)
    Abstract [en]

    A study was performed on the phonon modes and infrared dielectric functions of high-quality ZnO thin films. The pulsed laser deposition technique was used to deposit the ZnO films on c-plane sapphire substrates and were investigated by high-resolution transmission electron microscopy, high-resolution x-ray diffraction and Rutherford backscattering experiments. The accurate long-wavelength dielectric constant limits of the films were also obtained and were compared with near-band-gap index-of-refraction data upon the Lyddane-Sachs-Teller relation for both film and bulk samples. It was found that the phonon modes of the film were highly consistent with those of the bulk sample.

  • 12.
    Bechstedt, F.
    et al.
    Inst. Festkorpertheorie und -Optik, Friedrich-Schiller-Universität, Max-Wien-Platz 1, 07743 Jena, Germany.
    Furthmuller, J.
    Furthmüller, J., Inst. Festkorpertheorie und -Optik, Friedrich-Schiller-Universität, Max-Wien-Platz 1, 07743 Jena, Germany.
    Ambacher, O.
    Technische Universität Ilmenau, Zentrum Mikro- und Nanotechnologien, G.-Kirchhoff-Strasse 7, 98693 Ilmenau, Germany.
    Goldhahn, R.
    Technische Universität Ilmenau, Institut für Physik, PF 10 05 65, 98684 Ilmenau, Germany.
    Shubina, T.V.
    Ioffe Physico-Technical Institute, Polytekhnicheskaya 26, St. Petersburg 194021, Russian Federation.
    Ivanov, S.V.
    Ioffe Physico-Technical Institute, Polytekhnicheskaya 26, St. Petersburg 194021, Russian Federation.
    Jmerik, V.N.
    Ioffe Physico-Technical Institute, Polytekhnicheskaya 26, St. Petersburg 194021, Russian Federation.
    Kop'ev, P.S.
    Ioffe Physico-Technical Institute, Polytekhnicheskaya 26, St. Petersburg 194021, Russian Federation.
    Vasson, A.
    LASMEA-UMR 6602, CNRS-UBP, 63177 Aubiere Cedex, France.
    Leymarie, J.
    LASMEA-UMR 6602, CNRS-UBP, 63177 Aubiere Cedex, France.
    Kavokin, A.
    LASMEA-UMR 6602, CNRS-UBP, 63177 Aubiere Cedex, France.
    Amano, H.
    Meijo University, 1-501 Shiogamaguchi, Tempaku-ku, Nagoya 468-8502, Japan.
    Gil, B.
    Université Montpellier II, 34095 Montpellier, France.
    Briot, O.
    Université Montpellier II, 34095 Montpellier, France.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Comment on "Mie resonances, infrared emission, and the band gap of InN"2004In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 93, no 26 I, p. 269701-1p. 269701-1-Article in journal (Other academic)
    Abstract [en]

    [No abstract available]

  • 13.
    Bergman, Peder
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Pozina, Galia
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Dalfors, J.
    Sernelius, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics.
    Holtz, Per-Olof
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Amano, H.
    Akasaki, I.
    Radiative recombination in InGaN/GaN multiple quantum well2000In: ICSCRM 99,1999, 2000, p. 1571-Conference paper (Refereed)
  • 14.
    Bergman, Peder
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Pozina, Galia
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Kamiyama, S
    Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden Meijo Univ, Dept Elect Engn & Elect, Tempaku Ku, Nagoya, Aichi 468, Japan Meijo Univ, Elect & High Tech Res Ctr, Tempaku Ku, Nagoya, Aichi 468, Japan.
    Iwaya, M
    Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden Meijo Univ, Dept Elect Engn & Elect, Tempaku Ku, Nagoya, Aichi 468, Japan Meijo Univ, Elect & High Tech Res Ctr, Tempaku Ku, Nagoya, Aichi 468, Japan.
    Amano, H
    Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden Meijo Univ, Dept Elect Engn & Elect, Tempaku Ku, Nagoya, Aichi 468, Japan Meijo Univ, Elect & High Tech Res Ctr, Tempaku Ku, Nagoya, Aichi 468, Japan.
    Akasaki, I
    Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden Meijo Univ, Dept Elect Engn & Elect, Tempaku Ku, Nagoya, Aichi 468, Japan Meijo Univ, Elect & High Tech Res Ctr, Tempaku Ku, Nagoya, Aichi 468, Japan.
    Photoluminescence and electroluminescence characterization of InxGa1-x/InyGa1-yN multiple quantum well light emitting diodes2002In: Materials Science Forum, Vols. 389-393, 2002, Vol. 389-3, p. 1493-1496Conference paper (Refereed)
    Abstract [en]

    We report on a study of radiative recombination in In0.11Ga0.89N/In.0.01Ga0.99N multiple quantum wells (MQWs). The QWs were nominally undoped, while the InGaN barriers were Si doped. The MQW part is situated in the depletion field of a pn-junction structure with electrical contacts, so that both photoluminescence (PL) and electroluminescence (EL) can be studied as a function of bias. The PL and EL spectra are distinctly different, in particular at low temperatures. The spectral properties and related differences in PL decay times reflect different recombination conditions in the MQW region for the individual QWs.

  • 15.
    Bi, Zhaoxia
    et al.
    Solid State Lighting Center, the Nanometer Structure Consortium, Lund University, Box 118, 221 00 Lund, Sweden.
    Lindgren, David
    Solid State Lighting Center, the Nanometer Structure Consortium, Lund University, Box 118, 221 00 Lund, Sweden.
    Johansson, B. Jonas
    Solid State Lighting Center, the Nanometer Structure Consortium, Lund University, Box 118, 221 00 Lund, Sweden.
    Ek, Martin
    Center for Analysis and Synthesis/nCHREM, Lund University, Box 124, 221 00 Lund, Sweden.
    Wallenberg, L. Reine
    Center for Analysis and Synthesis/nCHREM, Lund University, Box 124, 221 00 Lund, Sweden.
    Gustafsson, Anders
    Solid State Lighting Center, the Nanometer Structure Consortium, Lund University, Box 118, 221 00 Lund, Sweden.
    Borgström, Magnus T
    Solid State Lighting Center, the Nanometer Structure Consortium, Lund University, Box 118, 221 00 Lund, Sweden.
    Ohlsson, Jonas
    QuNano AB, Ideon Science Park, Scheelevägen 17, 223 70 Lund, Sweden.
    Monemar, Bo
    Solid State Lighting Center, the Nanometer Structure Consortium, Lund University, Box 118, 221 00 Lund, Sweden.
    Samuelson, Lars
    Solid State Lighting Center, the Nanometer Structure Consortium, Lund University, Box 118, 221 00 Lund, Sweden.
    InN quantum dots on GaN nanowires grown by MOVPE2014In: Physica Status Solidi. C, Current topics in solid state physics, ISSN 1610-1634, E-ISSN 1610-1642, Vol. 11, no 3-4, p. 421-424Article in journal (Refereed)
    Abstract [en]

    In this work, growth of InN quantum dots (QDs) on GaN nanowires (NWs) by metal-organic vapour phase epitaxy is demonstrated, illustrating the feasibility to combine 0D and 1D structures for nitride semiconductors. Selective area growth was used to generate arrays of c-oriented GaN NWs using Si3N4 as the mask material. In general, InN QDs tend to form at the NW edges between the m-plane side facets, but the QD growth can also be tuned to the side facets by controlling the growth temperature and the growth rate. TEM characterization reveals that I1-type stacking faults are formed in the QDs and originate from the misfit dislocations at the InN/GaN interface. Photoluminescence measurement at 4 K shows that the peak shifts to high energy with reduced dot size. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

  • 16.
    Buyanova, Irina A.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials. Linköping University, The Institute of Technology.
    Chen, Weimin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Pozina, Galia
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Hai, P.N.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Xin, H.P.
    Department of Electrical and Computer Engineering, University of California, San Diego, CA 92093-0407, United States.
    Tu, C.W.
    Department of Electrical and Computer Engineering, University of California, San Diego, CA 92093-0407, United States.
    Optical properties of GaNAs/GaAs structures2001In: Materials Science & Engineering: B. Solid-state Materials for Advanced Technology, ISSN 0921-5107, E-ISSN 1873-4944, Vol. 82, no 1-3, p. 143-147Article in journal (Refereed)
    Abstract [en]

    We review our recent results on optical characterization of MBE-grown GaNAs/GaAs quantum structures with N content up to 4.5%, by employing photoluminescence (PL), PL excitation, and time-resolved PL spectroscopies. The dominant PL mechanism has been determined as recombination of excitons trapped by potential fluctuations of the band edge, due to composition disorder and strain nonuniformity of the alloy. The estimated value of the localization potential is around 60 meV for the low-temperature grown structures and can be reduced by increasing the growth temperature or using post-growth rapid thermal annealing (RTA). © 2001 Elsevier Science S.A.

  • 17.
    Buyanova, Irina A
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials. Linköping University, The Institute of Technology.
    Hallberg, T
    Linkoping Univ, Dept Phys & Measurement Technol, S-58183 Linkoping, Sweden Swedish Def Res Estab, S-58111 Linkoping, Sweden Inst Solid State & Semicond Phys, Minsk 220072, Byelarus Univ Lund, S-22100 Lund, Sweden.
    Murin, LI
    Linkoping Univ, Dept Phys & Measurement Technol, S-58183 Linkoping, Sweden Swedish Def Res Estab, S-58111 Linkoping, Sweden Inst Solid State & Semicond Phys, Minsk 220072, Byelarus Univ Lund, S-22100 Lund, Sweden.
    Markevich, VP
    Linkoping Univ, Dept Phys & Measurement Technol, S-58183 Linkoping, Sweden Swedish Def Res Estab, S-58111 Linkoping, Sweden Inst Solid State & Semicond Phys, Minsk 220072, Byelarus Univ Lund, S-22100 Lund, Sweden.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Lindstrom, JL
    Effect of high-temperature electron irradiation on the formation of radiative defects in silicon1999In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 274, p. 528-531Article in journal (Refereed)
    Abstract [en]

    Defect formation processes in silicon caused by electron irradiation performed at elevated temperatures are studied in detail using photoluminescence (PL) spectroscopy. The use of high temperature during electron irradiation has been found to affect considerably the defect formation process, In particular, several new unknown excitonic PL lines were discovered in carbon-rich Si wafers subjected to electron irradiation at temperatures higher than 450 degrees C, The dominant new luminescent center gives rise to a bound exciton PL emission at 0.961 eV. The center is shown to be efficiently created by electron irradiation at temperatures from 450 degrees C up to 600 degrees C. The electronic structure of the 0.961 eV PL center can be described as a pseudodonor case, where the hole is strongly bound at a level 187 meV above the valence band, while the electron is a effective-mass-like particle weakly bound by approximate to 21 meV in the BE state, (C) 1999 Elsevier Science B.V. All rights reserved.

  • 18.
    Buyanova, Irina A.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials. Linköping University, The Institute of Technology.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Lindstrom, J.L.
    Lindström, J.L., Solid State Physics, Univ. of Lund, Box 118, S-221 00, Lund, Sweden.
    Hallberg, T.
    Murin, L.I.
    Inst. Solid Stt. Semiconduct. Phys., 220072, Minsk, Belarus.
    Markevich, V.P.
    Inst. Solid Stt. Semiconduct. Phys., 220072, Minsk, Belarus.
    Photoluminescence characterization of defects created in electron-irradiated silicon at elevated temperatures2000In: Materials Science & Engineering: B. Solid-state Materials for Advanced Technology, ISSN 0921-5107, E-ISSN 1873-4944, Vol. 72, no 2, p. 146-149Article in journal (Refereed)
    Abstract [en]

    Photoluminescence (PL) spectroscopy is employed to investigate radiative defects created in Si during electron-irradiation at elevated temperatures. The use of high temperature during electron irradiation has been found to affect considerably the defect formation process. The effect critically depends on the temperature of the irradiation as well as doping of the samples. For carbon-lean Si wafers high temperature electron irradiation stimulates the formation of extended defects, such as dislocations and precipitates. For carbon-rich Si wafers the increase of irradiation temperature up to 300°C enhances the formation of the known carbon-related defects. In addition, several new excitonic PL lines were observed after electron irradiation at T = 450°C. The dominant new PL center gives rise to a BE PL emission at 0.961 eV. The electronic structure of the 0.961 eV defect is discussed based on temperature-dependent and magneto-optical studies.

  • 19.
    Buyanova, Irina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Chen, Weimin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Electronic Properties of Ga(In)NAs Alloys2001In: MRS Internet journal of nitride semiconductor research, ISSN 1092-5783, E-ISSN 1092-5783, Vol. 6Article in journal (Refereed)
    Abstract [en]

     A brief review on the present knowledge of the electronic properties of the Ga(In)NAs ternary and quaternary alloys is given mainly from an experimental perspective. The discussion is focused on Ga(In)NAs with low N composition (< 10 %), where a large amount of experimental work has been done. Important fundamental electronic properties of the material system are analyzed with the emphasis on the nature of the giant band gap bowing in the alloy and nitrogen-induced modifications of the electronic structure of the conduction band. The current knowledge of the key material parameters, relevant for the device applications, such as electron effective mass, recombination processes and band alignment in Ga(In)NAs/GaAs heterostructures, is also reviewed.

  • 20.
    Buyanova, Irina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Chen, Weimin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Toropov, A. A.
    Terentev, Ya. V.
    Sorokin, S. V.
    Lebedev, A. V.
    Ivanov, S. V.
    Kopev, P. S.
    On the spin injection in ZnMnSe/ZnCdSe heterostructures2002Conference paper (Refereed)
    Abstract [en]

     We present results from a detailed study of spin injection in thin II-VI wide band gap semiconductor heterostructures by magnetooptical spectroscopy. It is shown that efficient spin alignment can be achieved in a diluted magnetic semiconductor barrier (a layer of ZnMnSe or ZnMnSe/CdSe superlattice) as thin as 10 nm. Rather efficient spin injection from such a thin spin aligner to a non-magnetic quantum well is demonstrated, even when the tunneling energy barrier is as thick as 10 nm. The effect of spin relaxation process on spin injection is also closely examined.

  • 21.
    Buyanova, Irina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Chen, Weimin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Xin, H. P.
    Tu, C. W.
    Effect of Growth Conditions on the Photoluminescence of GaNAs/GaAs Quantum Structures1999In: Joint International Meeting the 196th Meeting of The Electrochemical Society ECS and the 1999 Fall Meeting of The Electrochemical Society of Japan ECSJ,1999, 1999, p. 774-Conference paper (Other academic)
  • 22.
    Buyanova, Irina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Chen, Weimin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Xin, H. P.
    Tu, C. W.
    Effect of growth temperature on photoluminescence of GaNAs/GaAs quantum well structures1999In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 75, no 24, p. 3781-Article in journal (Refereed)
    Abstract [en]

     The effect of growth temperature on the optical properties of GaAs/GaNxAs1-x quantum wells is studied in detail using photoluminescence (PL) spectroscopies. An increase in growth temperature up to 580 °C is shown to improve the optical quality of the structures, while still allowing one to achieve high (>3%) N incorporation. This conclusion is based on: (i) an observed increase in intensity of the GaNAs-related near-band-edge emission; (ii) a reduction in band-edge potential fluctuations, deduced from the analysis of the PL line shape; and (iii) a decrease in concentration of some extended defects detected under resonant excitation of the GaNAs. The thermal quenching of the GaNAs-related PL emission, however, is almost independent of the growth temperature and is attributed to a thermal activation of an efficient nonradiative recombination channel located in the GaNAs layers.

  • 23.
    Buyanova, Irina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Chen, Weimin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Xin, H. P.
    Tu, C. W.
    Photoluminescence characterization of GaNAs/GaAs structures grown by molecular beam epitaxy2000In: Materials Science & Engineering: B. Solid-state Materials for Advanced Technology, ISSN 0921-5107, E-ISSN 1873-4944, Vol. 75, no 2-3, p. 166-169Article in journal (Refereed)
    Abstract [en]

    A number of optical spectroscopies, including photoluminescence (PL), PL excitation and cathodoluminescence, are employed for characterization of GaNAs epilayers and GaAs/GaNxAs1-x quantum well structures grown by gas source molecular beam epitaxy at low temperature. The existence of strong potential fluctuations in the band edge of the GaNAs alloy is concluded, even for the samples with high optical quality, from a detailed analysis of the characteristic properties of the GaNAs-related PL emission. Based on the observed similarity in the PL properties between the GaNAs epilayers and the QW structures, the potential fluctuations are suggested to be mainly due to composition disorder and strain nonuniformity of the alloy. ⌐ 2000 Elsevier Science S.A. All rights reserved.

  • 24.
    Buyanova, Irina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Chen, Weimin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Xin, H. P.
    Tu, C. W.
    Resonant excitation spectroscopies of GaNAs/GaAs quantum structures2000Conference paper (Refereed)
    Abstract [en]

    We employ resonant optical excitation and Raman spectroscopies to study optical properties of GaNAs-based quantum structures grown by gas source molecular beam epitaxy (GS MBE). Under above band gap non-resonant excitation the PL spectra of GaNAs are shown to be dominated by the commonly observed featureless localised exciton emission. In contrast, when excitation energy is tuned close to the band edge of GaNAs alloy a series of additional narrow lines can be detected in the PL spectra. The peak positions of these lines are at about 10 meV (strongest), and at 20, 32, and 36 below the excitation energy. The dominant 10 meV line can only be excited within very narrow spectral range coinciding with the free exciton emission in GaNAs. Based on performed spectral, temperature dependent, and polarization studies the strongest 10 meV and the weaker 20 meV lines are tentatively attributed to disorder activated Raman scattering which is strongly enhanced close to the mobility edge of the GaNAs. The 32 and 36 meV lines are, on the other hand, caused by Raman scattering involving GaAs-like TO and LO phonons.

  • 25.
    Buyanova, Irina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Chen, Weimin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Pozina, Galia
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Bergman, Peder
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Xin, H. P.
    Tu, C. W.
    Mechanism for low-temperature photoluminescence in GaNAs/GaAs structures grown by molecular-beam epitaxy1999In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 75, no 4, p. 501-Article in journal (Refereed)
    Abstract [en]

     The mechanism for low-temperature photoluminescence (PL) emissions in GaNAs epilayers and GaAs/GaNxAs1 - x quantum well (QW) structures grown by molecular-beam epitaxy is studied in detail, employing PL, PL excitation, and time-resolved PL spectroscopies. It is shown that even though quantum confinement causes a strong blueshift of the GaNAs PL emission, its major characteristic properties are identical in both QW structures and epilayers. Based on the analysis of the PL line shape, its dependence on the excitation power and measurement temperature, as well as transient data, the PL emission is concluded to be caused by a recombination of excitons trapped by potential fluctuations in GaNAs.

  • 26.
    Buyanova, Irina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Chen, Weimin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Pozina, Galia
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Xin, H. P.
    Tu, C. W.
    Mechanism for Light Emission in GaNAs/GaAs Structures Grown by Molecular Beam Epitaxy1999In: Physica status solidi. B, Basic research, ISSN 0370-1972, E-ISSN 1521-3951, Vol. 216, no 1, p. 125-129Article in journal (Refereed)
    Abstract [en]

     A detailed photoluminescence (PL) study reveals that the low-temperature PL emission in GaNAs epilayers and GaAs/GaNxAs1 - x quantum well structures grown by molecular beam epitaxy is governed by recombination of localized excitons. This conclusion is based on the analysis of the PL lineshape, its dependence on the excitation power and measurement temperature, as well as PL transient data. The depth of the localization potential is estimated as about 60 meV, varying slightly among the different structures.

  • 27.
    Buyanova, Irina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Ivanov, Ivan Gueorguiev
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Chen, Weimin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Toropov, A. A.
    Terentev, Ya. V.
    Sorokin, S. V.
    Lebedev, A. V.
    Ivanov, S. V.
    Kopev, P. S.
    Tunable laser spectroscopy of spin injection in ZnMnSe/ZnCdSe quantum structures2002In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 81, no 12, p. 2196-Article in journal (Refereed)
    Abstract [en]

     Magneto-optical spectroscopy in combination with tunable laser excitation is employed to study exciton spin alignment and injection in ZnMnSe/ZnCdSe quantum structures. This approach enables us to selectively create preferred spin orientation and to separately monitor subsequent spin injection from individual spin states, thus shedding light on a possible source of spin loss. It is shown that the limited spin polarization in a nonmagnetic quantum well due to spin injection from a ZnMnSe-based diluted magnetic semiconductor (DMS) is not caused by a limited degree of spin alignment in the DMS, which is in fact complete, but rather occurs during subsequent processes.

  • 28.
    Buyanova, Irina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Wagner, Matthias
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Chen, Weimin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Edwards, N. V.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Lindström, J. L.
    Bremser, M. D.
    Davis, R. F.
    Amano, H.
    Akasaki, I.
    Electronic structure of the 0.88-eV luminescence center in electron-irradiated gallium nitride1999In: Physical review. B, Condensed matter and materials physics, Vol. 60, no 3, p. 1746-1751Article in journal (Refereed)
    Abstract [en]

     Photoluminescence (PL) spectroscopy is employed to determine the nature of a near-infrared PL emission with a no-phonon line at ∼0.88 eV, commonly present in electron-irradiated GaN. This PL emission is suggested to originate from an internal transition between a moderately shallow excited state (with an ionization energy ∼21 meV) and the deep ground state (with an ionization energy ∼900 meV) of a deep defect. The existence of a higher-lying second excited state related to the 0.88-eV PL center is also shown from temperature-dependent studies. A different electronic character of the wave functions related to the first and second excited states has been revealed by PL polarization measurements. Since the PL emission has been observed with comparable intensity in all electron-irradiated GaN samples independent of doping on the starting material, it is proposed that either native defects, or common residual contaminants or their complexes are involved. The substitutional ON donor (or related complex) is considered as the most probable candidate, based on the observed striking similarity in the local vibrational properties between the 0.88-eV PL centers and the substitutional OP donor in GaP.

  • 29.
    Buyanova, Irina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Wagner, Matthias
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Chen, Weimin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Lindström, J. L.
    Amano, H.
    Akasaki, I.
    Photoluminescence Spectroscopy of the 0.88 eV Emission in Electron-Irradiated GaN1999In: APS March Meeting,1999, 1999Conference paper (Other academic)
  • 30.
    Buyanova, Irina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Wagner, Matthias
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Chen, Weimin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Lindström, J. L.
    Amano, H.
    Aksaki, I.
    Effect of electron irradiation on optical properties of gallium nitride1999In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T79, p. 72-75Article in journal (Refereed)
    Abstract [en]

     The effect of electron irradiation on the optical properties of GaN epilayers is studied in detail by photoluminescence (PL) spectroscopy. The most common types of GaN material are used, i.e. strained heteroepitaxial layers grown on 6H SiC or Al2O3 substrates, and thick bulk-like layers with the conductivity varying from n-type to semi-insulating and p-type. The main effects of electron irradiation on all investigated samples are found to be as follows: (i) a radiation-induced quenching of excitonic emissions in the near band gap region; (ii) an appearance of broad overlapping PL emissions within the spectral range 0.7-1.1 eV and (iii) the appearance of a PL band with a sharp no-phonon (NP) line at around 0.88 eV followed by a rich phonon assisted sideband. The 0.88 eV band is shown to originate from an internal transition of a deep defect. With increasing temperature a hot PL line can be observed at about 2-4 meV above the NP line, originating from higher lying excited states of the defect. The electronic structure of the 0.88 eV defect is shown to be very sensitive to the internal strain field in the GaN epilayers.

  • 31.
    Chen, Weimin
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Buyanova, Irina
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Sörman, E.
    Hai, P. N.
    Wagner, Matthias
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Magneto-optical spectroscopy of defects in wide bandgap semiconductors: GaN and SiC2000In: Proceedings Conference on Optoelectronic and Microelectronic Materials and Devices, IEEE , 2000, p. 497-502Conference paper (Refereed)
    Abstract [en]

    We review recent progress in our understanding of intrinsic defects in GaN and SiC, gained from magneto-optical studies by Zeeman measurements and optically detected magnetic resonance. The two best-known intrinsic defects in these two wide bandgap semiconductors, i.e. the Ga interstitial in GaN and the silicon vacancy in SiC, are discussed in detail. The Ga interstitial is the first and only intrinsic defect in GaN that has so far been unambiguously identified, either in the presumably isolated form or in a family of up to three complexes. The silicon vacancy is among the most studied intrinsic defect in SiC, at least in two charge states, and yet still remains controversial.

  • 32.
    Chen, Weimin
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Buyanova, Irina
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Wagner, Matthias
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Lindström, J. L.
    Amano, H.
    Akasaki, I.
    Role of the Substitutional Oxygen Donor in the Residual n-type Conductivity in GaN1999Conference paper (Refereed)
    Abstract [en]

     A detailed photoluminescence (PL) study reveals a striking similarity in local vibrational properties of a defect center in GaN as compared to that for the substitutional OP donor in GaP. This observation could be interpreted as if the center is in fact related to the substitutional oxygen donor in GaN. The deep-level nature experimentally determined for the defect center calls for caution of a commonly referred model that the substitutional oxygen donor is responsible for the residual n-type conductivity in GaN.

  • 33.
    Chen, Weimin
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Hai, P. N.
    Buyanova, Irina
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Xin, H. P.
    Tu, C. W.
    Optical Detection of Cyclotron Resonance (ODCR) in GaNAs/GaAs Quantum Well Structures2000Conference paper (Refereed)
    Abstract [en]

    ODCR has been employed to study effective masses and carrier recombination in GaNAs/GaAs multi-quantum well (MQW) structures, prepared by MBE with the nitrogen composition up to 4.5 above GaAs bandgap excitation consists of the excitonic recombination within the GaNAs MQW, the band edge PL emissions from GaAs and a broad 0.8-eV PL of unknown origin. When monitoring these emissions under the above GaAs excitation, the ODCR spectrum is dominated by the electron and hole CR in GaAs, with effective mass values 0.07m0 and 0.5m_0, respectively. The ODCR mechanism is discussed in terms of hot carrier effects, resulting in a reduced carrier recombination in GaAs and an enhanced carrier trapping in the GaNAs MQW. Under resonant excitation of the GaNAs MQW only a broad ODCR signal can be observed corresponding to an effective mass value 0.1m_0, attributed to the electron CR in the GaNAs MQW, where a higher electron effective mass value and a much lower mobility are expected.

  • 34.
    Chen, Weimin
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Hai, P. N.
    Wagner, Matthias
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Buyanova, Irina
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Amano, H.
    Akasaki, I.
    Xin, H. P.
    Tu, C. W.
    Optical and Microwave Double Resonance of III-nitrides1999In: Joint International Meeting the 196th Meeting of The Electrochemical Society ECS and the 1999 Fall Meeting of The Electrochemical Society of Japan ECSJ,1999, 1999, p. 764-Conference paper (Other academic)
    Abstract [en]

      

  • 35.
    Choubina, Tatiana
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Glasov, M.M.
    Toropov, A.A.
    Ivchenko, E.L.
    Usui, A.
    Bergman, Peder
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Light diffusion in GaN epilayers2007In: 3rd International Conference on Spontaneous Coherence in Excitonic System,2007, 2007Conference paper (Other academic)
  • 36.
    Choubina, Tatiana
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Glazov, M.M.
    Toropov, A.A.
    Gippius, N.A.
    Bergman, Peder
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Usui, A.
    Vasson, A.
    Leymarie, J.
    Ivanov, Ivan Gueorguiev
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Kopev, P.S.
    Slow light in GaN2008In: 16th Int. Symp. ¿Nanostructures: Physics and Technology,2008, 2008, p. 257-Conference paper (Refereed)
  • 37.
    Choubina, Tatiana
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Glazov, M.M.
    Toropov, A.A.
    Gippius, N.A.
    Vasson, A.
    Leymarie, J.
    Kavokin, A.
    Usui, A.
    Bergman, Peder
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Pozina, Galia
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    The slow light in GaN2008In: ICPS2008,2008, 2008, p. 647-Conference paper (Refereed)
  • 38.
    Choubina, Tatiana
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Glazov, M.M.
    Toropov, A.A.
    Ivanov, Ivan Gueorguiev
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Gippius, N.A.
    Vasson, A.
    Leymaire, J.
    Kavokin, A.
    Usui, A.
    Bergman, Peder
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Pozina, Galia
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Realization of slow light in GaN crystals2008In: IWN 2008,2008, 2008Conference paper (Refereed)
  • 39.
    Darakchieva, V.
    et al.
    IFM Linköpings universitet.
    Paskov, Plamen
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Schubert, Mattias
    Fakultät für Physik und Geowissenshaften Universität Leipzig.
    Paskova, Tanja
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Arwin, Hans
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Optics .
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Amano, H.
    Dept of Electrical and Electronic Engineering Meijo University, Japan.
    Akasaki, I.
    Dept. of Electrical and Electronic Engineering Meijo University, Japan.
    Strain evolution and phonons in AlN/GaN superlattices2003Article in journal (Refereed)
    Abstract [en]

    AlN/GaN superlattices (SLs) with different periods grown on GaN buffer layers were studied by infrared spectroscopic ellipsometry (IRSE), Raman scattering (RS) and high-resolution reciprocal space mapping (RSM). The lattice parameters and the degree of strain in the GaN buffer and the SL constituents were determined. Phonon modes originating from the buffer layer and the SL sublayers were identified and their frequency shifts were correlated with the strain state of the films.

  • 40.
    Darakchieva, Vanya
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Beckers, Manfred
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Hultman, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Xie, Mengyao
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Monemar, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Carlin, J.-F
    Grandjean, N.
    Strain and compositional analyzes of Al-rich Al1-xInxN alloys grown by MOVPE: impact on the applicability of Vegard's rule2008In: Physica Status Solidi (C) Current Topics in Solid State Physics, 2008, p. 1859-1862Conference paper (Refereed)
    Abstract [en]

    We have studied composition and strain in Al1–xInxN films with 0.128 x 0.22 grown on GaN-buffered sapphire substrates by metalorganic vapor phase epitaxy. A good agreement between the In contents determined by Rutherford backscattering spectrometry (RBS) and Xray diffraction (XRD) is found for x 18, suggesting applicability of Vegard's rule in the narrow compositional range around the lattice matching to GaN. The increase of the In content up to x = 0.22 leads to a formation of sub-layers with a higher composition, accompanied by deviations from Vegard's rule. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

  • 41.
    Darakchieva, Vanya
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Beckers, Manfred
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Xie, Mengyao
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Monemar, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Carlin, J-. F.
    Feltin, E.
    Gonschorek, M.
    Grandjean, N.
    Effects of strain and composition on the lattice parameters and applicability of Vegard's rule in Al-rich Al1-x Inx N films grown on sapphire2008In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 103, no 10, p. 103513-Article in journal (Refereed)
    Abstract [en]

    The lattice parameters and strain evolution in Al1-x In x N films with 0.07≤x≤0.22 grown on GaN-buffered sapphire substrates by metal organic vapor phase epitaxy have been studied by reciprocal space mapping. Decoupling of compositional effects on the strain determination was accomplished by measuring the In contents in the films both by Rutherford backscattering spectrometry (RBS) and x-ray diffraction (XRD). Differences between XRD and RBS In contents are discussed in terms of compositions and biaxial strain in the films. It is suggested that strain plays an important role for the observed deviation from Vegard's rule in the case of pseudomorphic films. On the other hand, a good agreement between the In contents determined by XRD and RBS is found for Al1-x Inx N films with low degree of strain or partially relaxed, suggesting applicability of Vegard's rule in the narrow compositional range around the lattice matching to GaN. © 2008 American Institute of Physics.

  • 42.
    Darakchieva, Vanya
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Birch, Jens
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Paskov, Plamen
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Tungasmita, Sukkaneste
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Paskova, Tanja
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Strain evolution in high temperature AlN buffer layers for HVPE-GaN growth2002In: Physica status solidi. A, Applied research, ISSN 0031-8965, E-ISSN 1521-396X, Vol. 190, no 1, p. 59-64Article in journal (Refereed)
    Abstract [en]

    High temperature AlN buffer layers are deposited on a-plane sapphire by reactive magnetron sputtering. The effect of the buffer thickness on the AlN structural properties and surface morphology are studied in correlation with the subsequent hydride vapour phase epitaxy of GaN. A minimum degree of mosaicity and screw dislocation density is determined for a 50 nm thick AlN buffer. With increasing the AlN thickness, a strain relaxation occurs as a result of misfit dislocation generation and higher degree of mosaicity. A blue shift of the E-1(TO) frequency evaluated by means of infrared reflection spectroscopy is linearly correlated with an increase in biaxial compressive stress in the films through the IR stress factor k(E1)(b) = 2.57 +/- 0.26 cm(-1) GPa(-1).

  • 43.
    Darakchieva, Vanya
    et al.
    Linköping University, Department of Physics, Chemistry and Biology.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology.
    Schubert, M
    Paskova, Tanja
    Linköping University, Department of Physics, Chemistry and Biology.
    Tungasmita, S
    Wagner, G
    Kasic, A
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Strain-related structural and vibrational properties of thin epitaxial AIN layers2004In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 70, no 4, p. 045411-Article in journal (Refereed)
    Abstract [en]

    The effect of film thickness on the strain and structural properties of thin epitaxial AIN films has been investigated by high resolution x-ray diffraction techniques and transmission electron microscopy. As a result a sublayer model of the degree of strain and related defects for all films is proposed. A sublayer with low defect density and a strain gradient is found to be present in all films and it reaches a maximum thickness of 65 nm. The films are compressively strained and the strain relaxation after a thickness of 65 nm is shown to be accompanied by misfit dislocation generation and increase of the mosaic tilt. The vibrational properties of the films have been studied by generalized infrared spectroscopic ellipsometry. The proposed sublayer model has been successfully applied to the analysis of the ellipsometry data through model calculations of the infrared dielectric function which confirm the sublayer model. It is found that the strain gradient results in a gradient of the phonon mode frequencies and broadening parameter. The initial strain relaxation in the films leads to narrowing of the observable infrared modes, while further strain relaxation broadens the modes when substantial defect generation occurs.

  • 44.
    Darakchieva, Vanya
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Hofmann, T.
    Schubert, M.
    Lu, H.
    Schaff, W.J.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Conduction band effective mass anisotropy and nonparabolicity of InN2006In: 3rd Workshop on Indium Nitride,2006, 2006Conference paper (Refereed)
    Abstract [en]

    Invited talk

  • 45.
    Darakchieva, Vanya
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Hofmann, T.
    Schubert, M.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Lu, H.
    Schaff, W.J.
    Hsiao, C.-L.
    Liu, T.-W.
    Chen, L.-C.
    Muto, D.
    Nanishi, Y.
    New insight into the free carrier properties of InN2008In: International workshop on Nitride semiconductors IWN2008,2008, 2008Conference paper (Refereed)
    Abstract [en]

      

  • 46.
    Darakchieva, Vanya
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Hofmann, T.
    University of Nebraska-Lincoln, USA.
    Schubert, M.
    University of Nebraska-Lincoln, USA.
    Sernelius, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Giuliani, Finn
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Xie, Mengyao
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Persson, Per O. A.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Monemar, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Schaff, W. J.
    Cornell University, Ithaca, NY, USA.
    Hsiao, C.-L.
    National Taiwan University, Taipei, Taiwan.
    Chen, L.-C.
    National Taiwan University, Taipei, Taiwan.
    Nanishi, Y
    Ritsumeikan University, Shiga, Japan.
    Unravelling the free electron behavior in InN2008In: Optoelectronic and Microelectronic Materials and Devices, 2008, IEEE , 2008, p. 90-97Conference paper (Refereed)
    Abstract [en]

    Precise measurement of the optical Hall effect in InN using magneto-optical generalized ellipsometry at IR and THz wavelengths, allows us to decouple the surface accumulation and bulk electron densities in InN films by non-contact optical means and further to precisely measure the effective mass and mobilities for polarizations parallel and perpendicular to the optical axis. Studies of InN films with different thicknesses, free electron densities and surface orientations enable an intricate picture of InN free electron properties to emerge. Striking findings on the scaling factors of the bulk electron densities with film thickness further supported by transmission electron microscopy point to an additional thickness dependent doping mechanism unrelated to dislocations. Surface electron accumulation is observed to occur not only at polar but also at non-polar and semi-polar wurtzite InN, and zinc blende InN surfaces. The persistent surface electron density shows a complex behavior with bulk density and surface orientation. This behavior might be exploited for tuning the surface charge in InN.

  • 47.
    Darakchieva, Vanya
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Materials Science . Linköping University, The Institute of Technology.
    Hofmann, T
    University of Nebraska.
    Schubert, M
    University of Nebraska.
    Sernelius, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics . Linköping University, The Institute of Technology.
    Monemar, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Materials Science . Linköping University, The Institute of Technology.
    Persson, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Giuliani, Finn
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Alves, E
    Sacavem, Portugal.
    Lu, H
    Cornell University.
    Schaff, W J
    Cornell University.
    Free electron behavior in InN: On the role of dislocations and surface electron accumulation2009In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 94, no 2, p. 022109-Article in journal (Refereed)
    Abstract [en]

    The free electron behavior in InN is studied on the basis of decoupled bulk and surface accumulation electron densities in InN films measured by contactless optical Hall effect. It is shown that the variation in the bulk electron density with film thickness does not follow the models of free electrons generated by dislocation-associated nitrogen vacancies. This finding, further supported by transmission electron microscopy results, indicates the existence of a different thickness-dependent doping mechanism. Furthermore, we observe a noticeable dependence of the surface electron density on the bulk density, which can be exploited for tuning the surface charge in future InN based devices.

  • 48.
    Darakchieva, Vanya
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Lorenz, K
    Institute of Tecnology and Nucl, Portugal .
    Barradas, N P
    Institute of Tecnology and Nucl, Portugal .
    Alves, E
    Institute of Tecnology and Nucl, Portugal .
    Monemar, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Schubert, M
    University of Nebraska.
    Franco, N
    Institute of Tecnology and Nucl, Portugal .
    L Hsiao, C
    National Taiwan University.
    Chen, L C
    National Taiwan University.
    Schaff, W J
    Cornell University.
    Tu, L W
    National Sun Yat Sen University.
    Yamaguchi, T
    Ritsumeikan University.
    Nanishi, Y
    Ritsumeikan University.
    Hydrogen in InN: A ubiquitous phenomenon in molecular beam epitaxy grown material2010In: APPLIED PHYSICS LETTERS, ISSN 0003-6951, Vol. 96, no 8, p. 081907-Article in journal (Refereed)
    Abstract [en]

    We study the unintentional H impurities in relation to the free electron properties of state-of-the-art InN films grown by molecular beam epitaxy (MBE). Enhanced concentrations of H are revealed in the near surface regions of the films, indicating postgrowth surface contamination by H. The near surface hydrogen could not be removed upon thermal annealing and may have significant implications for the surface and bulk free electron properties of InN. The bulk free electron concentrations were found to scale with the bulk H concentrations while no distinct correlation with dislocation density could be inferred, indicating a major role of hydrogen for the unintentional conductivity in MBE InN.

  • 49.
    Darakchieva, Vanya
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Paskova, Tanja
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Einfeldt, S.
    Hommel, D
    Lourdudoss, S.
    Phonons in strained AlGaN/GaN superlattices2007In: 6th International Symposium on Blue Laser and Light Emitting Diodes,2006, Physica Status Solidi, vol C4: WILEYVCH Verlag GmbH & Co. KGaA , 2007, p. 170-Conference paper (Refereed)
  • 50.
    Darakchieva, Vanya
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Usui, A.
    On the lattice parameters of GaN2007In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 91, no 3, p. 031911-Article in journal (Refereed)
    Abstract [en]

    The lattice parameters of low-defect density, undoped bulk GaN fabricated by hydride vapor phase epitaxy (HVPE) on (0001) sapphire and subsequent substrate removal, are precisely determined using high-resolution x-ray diffraction. The obtained values, c=5.18523 Å and a=3.18926 Å, are compared with the lattice parameters of freestanding HVPE GaN from different sources and found to be representative for state-of-the-art undoped HVPE bulk GaN material. A comparison with bulk GaN fabricated by the high-pressure technique and homoepitaxial GaN is made, and significant differences in the lattice parameters are found. The observed differences are discussed and a possible explanation is suggested. © 2007 American Institute of Physics.

1234567 1 - 50 of 398
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf