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  • 201.
    Persson, Per
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Hultman, Lars
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Janson, M.S.
    Royal Institute of Technology, Solid State Electronics, P.O. Box E229, S-164 40 Kista-Stockholm, Sweden.
    Hallen, A.
    Hallén, A., Royal Institute of Technology, Solid State Electronics, P.O. Box E229, S-164 40 Kista-Stockholm, Sweden.
    Yakimova, Rositsa
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik.
    Panknin, D.
    FWIM Forschungszentrum Rossendorf, D-01474 Schoenfeld-Weissig, Germany.
    Skorupa, W.
    FWIM Forschungszentrum Rossendorf, D-01474 Schoenfeld-Weissig, Germany.
    On the nature of ion implantation induced dislocation loops in 4H-silicon carbide2002Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 92, nr 5, s. 2501-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    [No abstract available]

  • 202.
    Persson, P.O.A.
    et al.
    Persson, P.O.Å., School of Physics, University of Sydney, NSW 2006, Australia.
    Rosen, Johanna
    School of Physics, University of Sydney, NSW 2006, Australia.
    McKenzie, D.R.
    School of Physics, University of Sydney, NSW 2006, Australia.
    Bilek, M.M.M.
    School of Physics, University of Sydney, NSW 2006, Australia.
    Höglund, Carina
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    A solid phase reaction between Ti Cx thin films and Al2 O3 substrates2008Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 103, nr 6Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ti Cx thin films were deposited on Al2 O3 substrates at 900 °C by using a multiple cathode high current pulsed cathodic arc. The Ti:C pulse ratio and, hence, the composition was varied from C rich to Ti rich. It is found that the Al2 O3 substrate is decomposed and reacts with the Ti Cx film to incorporate significant amounts of O and Al in the growing film. When the stoichiometry is suitable, epitaxially oriented Ti2 AlC MAX phase with significant O incorporated is formed. The results indicate that Al2 O3 is not an ideal substrate material for the growth of transition metal carbides and MAX phase thin films. © 2008 American Institute of Physics.

  • 203. Petersson, L.-G.
    et al.
    Dannetun, Helen
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik. Linköpings universitet, Tekniska högskolan.
    Fogelberg, J.
    Lundström, Ingemar
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik. Linköpings universitet, Tekniska högskolan.
    Hydrogen adsorption states at the external and internal palladium surfaces of a Palladium-Silicondioxide-Silicon structure1985Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 58, s. 404-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The hydrogen adsorption states at the external and internal Pd surfaces of a hydrogen sensitive Pd‐SiO2‐Si (Pd‐MOS) structure have been studied in high and ultrahigh vacuum. The steady‐state response of the Pd‐MOS structure (due to the hydrogen present at the Pd‐SiO2 interface) shows a logarithmic dependence on hydrogen pressure, independent of external surface condition. The heat of adsorption of the internal surface is coverage dependent and described by ΔHiH0(1‐aθi) giving ΔH0≊1.4 eV/molecule with a=1. Thus, there are always hydrogen adsorption states available at the internal surface independent of the applied pressure. This is why the Pd‐MOS structure works as a hydrogen sensor over a large pressure range. The importance of a surface cleaning procedure in order to obtain an atomically clean Pd surface after Ar sputtering is pointed out. It is observed that a, probably carbon, contaminated Pd surface has hydrogen adsorption properties similar to those of the palladium‐oxide interface. A clean Pd surface has adsorption sites with smaller heat of adsorptions than those at the interface. Furthermore, these adsorption sites give an increase in work function, whereas a decrease in work function is observed at the interface. It is pointed out that the difference in the heat of adsorption between surface and interface hydrogen adsorption sites means that hydrogen atoms are detected at the interface even when the hydrogen coverage at the clean surface is very small.

  • 204.
    Pettersson, H
    et al.
    Halmstad University.
    Landin, L
    Halmstad University.
    Kleverman, M
    Lund University.
    Seifert, W
    Lund University.
    Samuelson, L
    Lund University.
    Fu, Y
    Chalmers Institute of Technology and Gothenburg University.
    Willander, Magnus
    Chalmers Institute of Technology and Gothenburg University.
    Intersubband photoconductivity of self-assembled InAs quantum dots embedded in InP2004Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 95, nr 4, s. 1829-1831Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this article, we present the results from photoconductivity measurements in the infrared spectral region (3-10 mum) on ensembles of self-assembled InAs quantum dots embedded in a matrix of InP. In the spectral distribution of the photocurrent, peaks are observed which we interpret in terms of transitions from the dots ground- and first-excited states to the conduction band of the dots/matrix. Furthermore, we have calculated the expected photoresponse and found it to be in qualitative agreement with our experimental data.

  • 205.
    Pettersson, Lars
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Roman, L.S.
    Inganäs, Olle
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik.
    Quantum efficiency of exciton-to-charge generation in organic photovoltaic devices2001Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 89, nr 10, s. 5564-5569Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present an analysis of the internal monochromatic quantum efficiency of photovoltaic devices based on polymer and polymer/fullerene thin films. A quantum efficiency of exciton-to-charge generation is defined as the external monochromatic quantum efficiency normalized to the absorption in the active materials of the device. An upper limit of the efficiency can be determined, and results show that much of the light is absorbed in photoactive layers of the device, whereas only a fraction of the generated excitons is converted to charge carriers and can be collected as photocurrent. © 2001 American Institute of Physics.

  • 206.
    Philipps, Jan M.
    et al.
    Justus Liebig Univ Giessen, Germany.
    Holzel, Sara
    Univ Bremen, Germany.
    Hille, Pascal
    Univ Bremen, Germany.
    Schoermann, Joerg
    Justus Liebig Univ Giessen, Germany.
    Chatterjee, Sangam
    Justus Liebig Univ Giessen, Germany; Justus Liebig Univ Giessen, Germany.
    Buyanova, Irina
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten.
    Eickhoff, Martin
    Univ Bremen, Germany.
    Hofmann, Detlev M.
    Justus Liebig Univ Giessen, Germany.
    Photoelectrochemical response of GaN, InGaN, and GaNP nanowire ensembles2018Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 123, nr 17, artikkel-id 175703Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The photoelectrochemical responses of GaN, GaNP, and InGaN nanowire ensembles are investigated by the electrical bias dependent photoluminescence, photocurrent, and spin trapping experiments. The results are explained in the frame of the surface band bending model. The model is sufficient for InGaN nanowires, but for GaN nanowires the electrochemical etching processes in the anodic regime have to be considered additionally. These processes lead to oxygen rich surface (GaxOy) conditions as evident from energy dispersive X-ray fluorescence. For the GaNP nanowires, a bias dependence of the carrier transfer to the electrolyte is not reflected in the photoluminescence response, which is tentatively ascribed to a different origin of radiative recombination in this material as compared to (In) GaN. The corresponding consequences for the applications of the materials for water splitting or pH-sensing will be discussed. Published by AIP Publishing.

  • 207.
    Philipps, Jan M.
    et al.
    I. Physikalisches Institut, Justus-Liebig-Universitaet Giessen, D-35392 Giessen, Germany .
    Stehr, Jan Eric
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Funktionella elektroniska material. Linköpings universitet, Tekniska högskolan.
    Buyanova, Irina
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Funktionella elektroniska material. Linköpings universitet, Tekniska högskolan.
    Tarun, Marianne C.
    Department of Physics and Astronomy and Materials Science Program, Washington State University, Pullman, Washington 99164-2814, USA.
    McCluskey, Matthew D.
    Department of Physics and Astronomy and Materials Science Program, Washington State University, Pullman, Washington 99164-2814, USA.
    Meyer, Bruno K.
    I. Physikalisches Institut, Justus-Liebig-Universitaet Giessen, D-35392 Giessen, Germany.
    Hofmann, Detlev M.
    I. Physikalisches Institut, Justus-Liebig-Universitaet Giessen, D-35392 Giessen, Germany.
    Recharging behavior of nitrogen-centers in ZnO2014Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 116, nr 063701Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electron Paramagnetic Resonance was used to study N2-centers in ZnO, which show a 5-line spectrum described by the hyperfine interaction of two nitrogen nuclei (nuclear spin I  = 1, 99.6% abundance). The recharging of this center exhibits two steps, a weak onset at about 1.4 eV and a strongly increasing signal for photon energies above 1.9 eV. The latter energy coincides with the recharging energy of NO centers (substitutional nitrogen atoms on oxygen sites). The results indicate that the N2-centers are deep level defects and therefore not suitable to cause significant hole-conductivity at room temperature.

  • 208.
    Pilch, Iris
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Greiner, Franko
    Christian Albrechts University of Kiel, Germany.
    Diagnostics of void expansion during cyclic growth and formation of layered nanoparticle clouds2017Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 121, nr 11, artikkel-id 113302Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nanoparticles were grown in an argon-acetylene plasma, and the particle size was characterized during growth using imaging Mie ellipsometry (I-Mie). The typical cyclic growth was observed, and the previously reported expansion and contraction of the void before depletion of nanoparticles [van de Wetering et al., J. Phys. D: Appl. Phys. 48, 035204 (2015)] was independently confirmed in our measurements. The cyclic growth was interrupted by repetitively turning the acetylene flow on and off. The nanoparticles that were confined in the discharge proceeded to grow slowly but more importantly a new growth cycle started with nucleation and growth taking place in the void region. The additional growth burst in the void region leads to a structured dust cloud with regions of nanoparticles with different sizes that were sharply separated. The advantages of using the I-Mie diagnostics for the observation of nanoparticles compared to standard video microscopy are demonstrated for the structured dust cloud. The results are discussed in relation to the growth processes for nucleation and coagulation.

  • 209.
    Pozina, Galia
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik.
    Bergman, JP
    Linkoping Univ, Dept Phys & Measurement Technol, S-58183 Linkoping, Sweden Meijo Univ, Dept Elect Engn & Elect, Tempaku Ku, Nagoya, Aichi 4688502, Japan Meijo Univ, High Tech Res Ctr, Tempaku Ku, Nagoya, Aichi 4688502, Japan.
    Monemar, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik.
    Takeuchi, T
    Linkoping Univ, Dept Phys & Measurement Technol, S-58183 Linkoping, Sweden Meijo Univ, Dept Elect Engn & Elect, Tempaku Ku, Nagoya, Aichi 4688502, Japan Meijo Univ, High Tech Res Ctr, Tempaku Ku, Nagoya, Aichi 4688502, Japan.
    Amano, H
    Linkoping Univ, Dept Phys & Measurement Technol, S-58183 Linkoping, Sweden Meijo Univ, Dept Elect Engn & Elect, Tempaku Ku, Nagoya, Aichi 4688502, Japan Meijo Univ, High Tech Res Ctr, Tempaku Ku, Nagoya, Aichi 4688502, Japan.
    Akasaki, I
    Linkoping Univ, Dept Phys & Measurement Technol, S-58183 Linkoping, Sweden Meijo Univ, Dept Elect Engn & Elect, Tempaku Ku, Nagoya, Aichi 4688502, Japan Meijo Univ, High Tech Res Ctr, Tempaku Ku, Nagoya, Aichi 4688502, Japan.
    Origin of multiple peak photoluminescence in InGaN/GaN multiple quantum wells2000Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 88, nr 5, s. 2677-2681Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Optical spectroscopy has been performed for a set of In0.12Ga0.88N/GaN multiple quantum wells (MQW) grown by metalorganic vapor phase epitaxy at 820 degrees C. Time-resolved, temperature- and power-dependent photoluminescence as well as spatially-resolved cathodoluminescence measurements have been applied to elucidate the nature of the recombination mechanisms responsible for the radiative transitions in the samples. The photoluminescence spectra in this set of samples are dominated by strong multiple peak emissions associating with both confined levels of the MQW system (the higher energy band) and with strongly localized states of energies much lower than the QW band gap. We suggest that the photoluminescence originate from (i) the MQW exciton recombination, (ii) excitons localized in the quasidot regions with indium concentrations higher than in the alloy due to segregation processes, and (iii) from localized states in zero-dimensional quantum islands created by surface defects such as pits and V defects. Buried side-wall quantum wells caused by V defects might also influence the photoluminescence spectra. (C) 2000 American Institute of Physics. [S0021-8979(00)00117-1].

  • 210.
    Pozina, Galia
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Hemmingsson, Carl
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Forsberg, Urban
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Lundskog, Anders
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Kakanakova-Georgieva, Anelia
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial.
    Monemar, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Time-resolved photoluminescence properties of AlGaN/AlN/GaN high electron mobility transistor structures grown on 4H-SiC substrate2008Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 104, nr 11, s. 113513-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    AlGaN/AlN/GaN high electron mobility transistor heterostructures grown by metal-organic chemical vapor deposition have been studied by temperature dependent time-resolved photoluminescence. The AlGaN-related emission is found to be sensitive to the excitation power and to the built-in internal electric field. In addition, this emission shows a shift to higher energy with the reduction in the excitation density, which is rather unusual. Using a self-consistent calculation of the band potential profile, we suggest a recombination mechanism for the AlGaN-related emission involving electrons confined in the triangular AlGaN quantum well and holes weakly localized due to potential fluctuations.

  • 211.
    Puttisong, Yuttapoom
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Funktionella elektroniska material. Linköpings universitet, Tekniska högskolan.
    Buyanova, Irina
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Funktionella elektroniska material. Linköpings universitet, Tekniska högskolan.
    Geelhaar, L
    Paul Drude Institute Festkorperelekt.
    Riechert, H
    Paul Drude Institute Festkorperelekt.
    Tu, C W
    University of California San Diego.
    Chen, Weimin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Funktionella elektroniska material. Linköpings universitet, Tekniska högskolan.
    Efficient room-temperature spin detector based on GaNAs2012Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 111, nr 7, s. 07C303-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Efficient and highly spin-dependent recombination processes are shown to not only turn GaNAs into an efficient spin filter but also to make it an excellent spin detector functional at room temperature (RT). By taking advantage of the defect-engineered spin-filtering effect, the spin detection efficiency is no longer limited by the fast spin relaxation of conduction electrons. This leads to a significant enhancement in the optical polarization of the spin detector, making it possible to reliably detect even very weak electron spin polarization at RT, as demonstrated by a study of spin loss during optical spin injection across a GaAs/GaNAs interface.

  • 212.
    Qiu, X. Y.
    et al.
    Nanjing University, Peoples R China.
    Liu, H. W.
    Nanjing University, Peoples R China.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Liu, J. -M.
    Nanjing University, Peoples R China.
    Thermal stability and interfacial properties of ZrAlxSiyOz films prepared by pulse-laser deposition2006Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 100, nr 7, s. 074109-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The thermal stability and interfacial properties of amorphous ZrAlxSiyOz films prepared under high vacuum conditions by pulse-laser deposition are investigated. A high anticrystallization temperature of 916 degrees C is identified by x-ray diffraction and differential scanning calorimeter. However, it is found that ZrOx clusters may precipitate from amorphous film matrix at a temperature as low as 700 degrees C, which subsequently react with Si substrate to form amorphous Zr-silicide interfacial layer. Due to the conductivity and good interfacial morphology of amorphous Zr-silicide interfacial layer, the Pt/ZrAlxSiyOz/IL/Si stack gate structures exhibit good electrical properties such as small equivalent oxide thickness of 0.9 nm, flatband voltage of 0.43 V, and low leakage density of 64 mA/cm(2) at 1 V gate voltage. (c) 2006 American Institute of Physics.

  • 213.
    Ratnikov, V
    et al.
    Linkoping Univ, S-58183 Linkoping, Sweden Russian Acad Sci, Ioffe Inst, St Petersburg 194021, Russia Univ Sofia, Fac Phys, BU-1164 Sofia, Bulgaria.
    Kyutt, R
    Linkoping Univ, S-58183 Linkoping, Sweden Russian Acad Sci, Ioffe Inst, St Petersburg 194021, Russia Univ Sofia, Fac Phys, BU-1164 Sofia, Bulgaria.
    Shubina, Tatiana
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Paskova, Tanja
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Valcheva, E
    Linkoping Univ, S-58183 Linkoping, Sweden Russian Acad Sci, Ioffe Inst, St Petersburg 194021, Russia Univ Sofia, Fac Phys, BU-1164 Sofia, Bulgaria.
    Monemar, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik.
    Bragg and Laue x-ray diffraction study of dislocations in thick hydride vapor phase epitaxy GaN films2000Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 88, nr 11, s. 6252-6259Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The dislocation structure of hydride vapor phase epitaxial thick GaN layers grown on sapphire is studied by analysis of the microdistortion tensor components. Symmetrical reflections (including reflections from planes forming a large angle with the basal plane) with two modes of scanning (theta and theta -2 theta) in two geometries (Bragg and Laue) are used to obtain the tensor components. The instant connections between the tensor components and major dislocation types are specified. Different types of dislocation distributions have been identified in the thick GaN films grown on sapphire with and without undoped and Si-doped metalorganic chemical vapor deposited templates. Transmission electron microscopy was used to confirm the x-ray results by direct visualization of defect rearrangements. (C) 2000 American Institute of Physics. [S0021-8979(00)06023-0].

  • 214.
    Reeswinkel, Thomas
    et al.
    RWTH Aachen University.
    Sangiovanni, Davide Giuseppe
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Chirita, Valeriu
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Schneider, Jochen
    RWTH Aachen University.
    Structure and mechanical properties of TiAlN-WNx thin films2010Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550Artikkel i tidsskrift (Fagfellevurdert)
  • 215.
    Reichardt, H.
    et al.
    Ecole Polytechnique Fédérale de Lausanne.
    Leifer, K.
    Ecole Polytechnique Fédérale de Lausanne.
    Pelucchi, E.
    Ecole Polytechnique Fédérale de Lausanne.
    Karlsson, Fredrik
    Ecole Polytechnique Fédérale de Lausanne.
    Weman, Helge
    Ecole Polytechnique Fédérale de Lausanne.
    Rudra, A.
    Ecole Polytechnique Fédérale de Lausanne.
    Kapon, E.
    Ecole Polytechnique Fédérale de Lausanne.
    Influence of long-range substrate roughness on disorder in V-groove quantum wire structures2006Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 100, s. 123509-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The observation and the interpretation of line splitting in photoluminescence and cathodoluminescence spectra of GaAs/AlGaAs V-groove quantum wires (QWRs) are reported. The QWR emission line splits into two peaks whose intensities oscillate systematically along the axis of the wire. Combining atomic force microscopy and cathodoluminescence measurements, we show a clear correlation between the surface topography of the V-groove and the individual peak intensities. We elucidate the relationship between the V-groove sidewall roughness and the shape at its bottom, and explain their impact on the QWR formation using a two-dimensional growth model accounting for self-limited growth in each V-groove domain. The influence of the long-range substrate roughness on the QWR spectral features is thus clarified. The study provides guidelines for improving QWR uniformity in order to achieve near-ideal model systems for one-dimensional semiconductors

  • 216.
    Riaz, M
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Fulati, Alimujiang
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Amin, Gul
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Alvi, N H
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Nour, Omer
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Buckling and elastic stability of vertical ZnO nanotubes and nanorods2009Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 106, nr 3, s. 034309-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Buckling and elastic stability study of vertical well aligned ZnO nanorods grown on Si substrate and ZnO nanotubes etched from the same nanorods was done quantitatively by nanoindentation technique. The critical load, modulus of elasticity, and flexibility of the ZnO nanorods and nanotubes were observed and we compared these properties for the two nanostructures. It was observed that critical load of nanorods (2890 mu N) was approximately five times larger than the critical load of the nanotubes (687 mu N). It was also observed that ZnO nanotubes were approximately five times more flexible (0.32 nm/mu N) than the nanorods (0.064 nm/mu N). We also calculated the buckling energies of the ZnO nanotubes and nanorods from the force displacement curves. The ratio of the buckling energies was also close to unity due to the increase/decrease of five times for one parameter (critical load) and increase/decrease of five times for the other parameter (displacement) of the two samples. We calculated critical load, critical stress, strain, and Young modulus of elasticity of single ZnO nanorod and nanotube. The high flexibility of the nanotubes and high elasticity of the ZnO nanorods can be used to enhance the efficiency of piezoelectric nanodevices. We used the Euler buckling model and shell cylindrical model for the analysis of the mechanical properties of ZnO nanotubes and nanorods.

  • 217.
    Roder, C.
    et al.
    Institute of Solid State Physics, University of Bremen, P.O. Box 330440, 28334 Bremen, Germany.
    Einfeldt, S.
    Institute of Solid State Physics, University of Bremen, P.O. Box 330440, 28334 Bremen, Germany, Ferdinand-Braun-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, 12489 Berlin, Germany.
    Figge, S.
    Institute of Solid State Physics, University of Bremen, P.O. Box 330440, 28334 Bremen, Germany.
    Paskova, T.
    Institute of Solid State Physics, University of Bremen, P.O. Box 330440, 28334 Bremen, Germany.
    Hommel, D.
    Institute of Solid State Physics, University of Bremen, P.O. Box 330440, 28334 Bremen, Germany.
    Paskov, Plamen
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik.
    Monemar, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik.
    Behn, U.
    Fachhochschule Schmalkalden, Blechhammer 4-9, 98574 Schmalkalden, Germany.
    Haskell, B.A.
    Haskell, B.A..
    Fini, P.T.
    Fini, P.T..
    Nakamura, S.
    Nakamura, S..
    Stress and wafer bending of a -plane GaN layers on r -plane sapphire substrates2006Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 100, nr 10Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The stress and wafer bending of (11 2- 0) a -plane GaN layers of different thicknesses grown on (1 1- 02) r -plane sapphire substrates by hydride vapor phase epitaxy were studied by high-resolution x-ray diffraction and photoluminescence and photoreflectance spectroscopies. The layers are found to be under compression in the growth plane and under tension in the growth direction. The elastic and thermal anisotropies of the GaN and the sapphire crystal result in an in-plane stress and a wafer curvature, both of which are different in the two in-plane directions parallel and perpendicular to the GaN c axis. The GaN unit cell is no longer hexagonal but orthorhombic. The stress relaxes with increasing GaN layer thickness while the curvature of the wafer increases. Different stress relief mechanisms are considered, and the stresses in the layer and the curvature of the wafer are calculated using standard models on wafer bending. The results suggest that the wafer bending is the dominant stress relief mechanism. In addition, the redshift of the near-band-edge photoluminescence and the free exciton photoreflectance peaks with increasing layer thickness is correlated with the strain data determined by x-ray diffraction. © 2006 American Institute of Physics.

  • 218.
    Rogström, Lina
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Ghafoor, Naureen
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Schroeder, Jeremy
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Schell, N.
    Helmholtz Zentrum Geesthacht, Germany.
    Birch, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Ahlgren, M.
    Sandvik Coromant, Sweden.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Thermal stability of wurtzite Zr1-xAlxN coatings studied by in situ high-energy x-ray diffraction during annealing2015Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 118, nr 3, artikkel-id 035309Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We study the thermal stability of wurtzite (w) structure ZrAlN coatings by a combination of in situ high-energy x-ray scattering techniques during annealing and electron microscopy. Wurtzite structure Zr1-xAlxN coatings with Al-contents from x = 0.46 to x = 0.71 were grown by cathodic arc evaporation. The stability of the w-ZrAlN phase depends on chemical composition where the higher Al-content coatings are more stable. The wurtzite ZrAlN phase was found to phase separate through spinodal decomposition, resulting in nanoscale compositional modulations, i.e., alternating Al-rich ZrAlN layers and Zr-rich ZrAlN layers, forming within the hexagonal lattice. The period of the compositional modulations varies between 1.7 and 2.5 nm and depends on the chemical composition of the coating where smaller periods form in the more unstable, high Zr-content coatings. In addition, Zr leaves the w-ZrAlN lattice to form cubic ZrN precipitates in the column boundaries. (C) 2015 AIP Publishing LLC.

  • 219.
    Rosen, Johanna
    et al.
    Rhein Westfal TH Aachen.
    Anders, A
    Lawrence Berkeley National Laboratory.
    Mraz, S
    Rhein Westfal TH Aachen.
    Atiser, A
    Rhein Westfal TH Aachen.
    Schneider, JM
    Rhein Westfal TH Aachen.
    Influence of argon and oxygen on charge-state-resolved ion energy distributions of filtered aluminum arcs2006Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 99, nr 12, s. 123303-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The charge-state-resolved ion energy distributions (IEDs) in filtered aluminum vacuum arc plasmas were measured and analyzed at different oxygen and argon pressures in the range of 0.5-8.0 mTorr. A significant reduction of the ion energy was detected as the pressure was increased, most pronounced in an argon environment and for the higher charge states. The corresponding average charge state decreased from 1.87 to 1.0 with increasing pressure. The IEDs of all metal ions in oxygen were fitted with shifted Maxwellian distributions. The results show that it is possible to obtain a plasma composition with a narrow charge-state distribution as well as a narrow IED. These data may enable tailoring thin film properties through selecting growth conditions that are characterized by predefined charge state and energy distributions.

  • 220.
    Rosen, Johanna
    et al.
    RWTH, Aachen, Germany.
    Anders, A
    Lawrence Berkeley Laboratory.
    Mraz, S
    RWTH, Aachen, Germany.
    Schneider, JM
    RWTH, Aachen, Germany.
    Charge-state-resolved ion energy distributions of aluminum vacuum arcs in the absence and presence of a magnetic field2005Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 97, nr 10, s. 103306-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The charge-state-resolved ion energy distributions (IEDs) of aluminum vacuum are plasma species were measured and analyzed for different geometric and magnetic field configurations. The IEDs were fitted by shifted Maxwellian distributions. Plasma expansion in the absence of a magnetic field showed higher ion energies for higher charge states. The introduction of a magnetic field (independent of geometric configuration) resulted in a broader distribution and increased average ion energies. The energy gain was approximately proportional to the charge state, which may be due to the presence of electric fields in the magnetized plasma. The evolution of ion energy distributions is relevant to thin-film growth, and it is shown that the IEDs can be modified by suitable magnetic field configurations.

  • 221.
    Rosen, Johanna
    et al.
    University of Sydney.
    Ryves, L.
    University of Sydney.
    Persson, P. O. A.
    University of Sydney.
    Bilek, M. M. M.
    University of Sydney.
    Deposition of epitaxial Ti2AlC thin films by pulsed cathodic arc2007Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 101, nr 5, s. 056101-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A multicathode high current pulsed cathodic arc has been used to deposit Ti2AlC thin films belonging to the group of nanolaminate ternary compounds of composition M(n+1)AX(n). The required stoichiometry was achieved by means of alternating plasma pulses from three independent cathodes. We present x-ray diffraction and transmission electron microscopy analysis showing that epitaxial single phase growth of Ti2AlC has been achieved at a substrate temperature of 900 degrees C. Our results demonstrate a powerful method for MAX phase synthesis, allowing for phase tuning within the M(n+1)AX(n) system.

  • 222.
    Rosén, Johanna
    et al.
    Materials Chemistry, RWTH-Aachen.
    Anders, A.
    Lawrence Berkeley National Laboratory, California.
    Hultman, Lars
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Schneider, J.M.
    Materials Chemistry, RWTH-Aachen.
    Charge state and time resolved plasma composition of a pulsed zirconium arc in a nitrogen environment2004Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 96, nr 9, s. 4793-4799Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The species and ion charge state evolution of a pulsed cathodic arc plasma was investigated at different pressures. A zirconium cathode was operated in a nitrogen environment, and the plasma composition was analyzed by time-of-flight charge-to-mass spectrometry. Large plasma chemistry changes were detected with respect to time and pressure, The 250 µs plasma pulse can be divided in two characteristic phases: a transient phase before 150 µs and a steady state phase for all later times. The measured changes in plasma chemistry in the transient phase at p~10-5 Torr are explained by charge transfer collisions, while the increasing N+ fraction in the p > 10 -5 Torr range most likely originates from erosion of the nitrided cathode surface. In the steady-state phase, a pressure-induced change from higher to lower charge states was observed, which was mainly due to scattering of self-sputtered metal followed by metal ion-atom charge exchange collisions. These results are of importance for understanding the evolution of thin film composition and microstructure during reactive plasma deposition. © 2004 American Institute of Physics.

  • 223.
    Rosén, Johanna
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Anders, A.
    Lawrence Berkeley Natl. Laboratory, Berkeley, CA 94720, United States.
    Hultman, Lars
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Schneider, J.M.
    Materials Chemistry, RWTH-Aachen, D-52056 Aachen, Germany.
    Temporal development of the composition of Zr and Cr cathodic arc plasma streams in a N2 environment2003Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 94, nr 3, s. 1414-1419Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The development of the plasma composition in a pulsed plasma stream generated by cathodic arc was described. The time-resolved plasma composition for the cathode materials was analyzed by using time-of-flight charge-to-mass spectrometry. The results showed that the average charge state was affected by the reactive gas pressure and also by the time after ignition.

  • 224.
    Sahalianov, Ihor
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Radchenko, Taras M.
    NAS Ukraine, Ukraine.
    Tatarenko, Valentyn A.
    NAS Ukraine, Ukraine.
    Cuniberti, Gianaurelio
    Tech Univ Dresden, Germany; Tech Univ Dresden, Germany; Tech Univ Dresden, Germany; Tech Univ Dresden, Germany.
    Prylutskyy, Yuriy I
    Taras Shevchenko Natl Univ Kyiv, Ukraine.
    Straintronics in graphene: Extra large electronic band gap induced by tensile and shear strains2019Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 126, nr 5, artikkel-id 054302Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The possibility of inducing a sizeable energy gap in the electronic structure of a graphene layer is still one of the biggest and most debated challenges in graphene electronics. Despite promising theoretical results, some experimental studies report the absence of a bandgap even in highly mechanically strained graphene. In this paper, we address the main reasons for these discrepancies and study the influence of uniaxial tensile and shear strains as well as their combinations on the eventual bandgap opening in monolayer graphene. Deformation-dependent bandgap diagrams are constructed over a wide range of the strain tensor parameters of up to 26%, which is close to predicted graphene breaking point. The use of a combination of shear strain and uniaxial tensile deformations is found to be the easiest way for bandgap opening and tuning. The results of our numerical calculations demonstrate that shear strains can induce a bandgap of up to 4eV at the largest elastic deformations, while a combination of shear and uniaxial strains can provide an energy gap of up to 6eV that is substantially higher than for some materials (including silicon) typically used in nanoelectronic devices. The numerically obtained findings are carefully contrasted with other results available in the literature.

  • 225.
    Salikhov, R.
    et al.
    University of Duisburg Essen, Germany.
    Meshkian, Rahele
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Weller, D.
    University of Duisburg Essen, Germany.
    Zingsem, B.
    University of Duisburg Essen, Germany; Forschungszentrum Julich, Germany; Forschungszentrum Julich, Germany.
    Spoddig, D.
    University of Duisburg Essen, Germany.
    Lu, Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Ingason, Arni Sigurdur
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Zhang, H.
    Technical University of Darmstadt, Germany.
    Rosén, Johanna
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Wiedwald, U.
    University of Duisburg Essen, Germany.
    Farle, M.
    University of Duisburg Essen, Germany; Immanuel Kant Baltic Federal University, Russia.
    Magnetic properties of nanolaminated (Mo0.5Mn0.5)(2)GaC MAX phase2017Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 121, nr 16, artikkel-id 163904Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The magnetic properties of hexagonal (Mo0.5Mn0.5)(2)GaC MAX phase synthesized as epitaxial films on MgO (111) substrates with the c-axis perpendicular to the film plane are presented. The analysis of temperature-dependent ferromagnetic resonance (FMR) and magnetometry data reveals a ferro-to paramagnetic phase transition at 220 K. The electrical transport measurements at 5K show a negative magnetoresistance of 6% in a magnetic field of 9 T. Further analysis confirms the spin-dependent scattering of charge carriers in this layered material. A small perpendicular (c-axis) magnetocrystalline anisotropy energy density (MAE) of 4.5 kJ/m(3) at 100K was found using FMR. Accordingly, (Mo0.5Mn0.5)(2)GaC behaves similar to the (Cr0.5Mn0.5)(2)GaC MAX phase as a soft magnetic material. The density functional theory calculations reveal that the sign and the amplitude of the MAE can be very sensitive to (Mo0.5Mn0.5)(2)GaC lattice parameters, which may explain the measured soft magnetic properties. Published by AIP Publishing.

  • 226.
    Salomonsson, Anette
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik. Linköpings universitet, Tekniska högskolan.
    Eriksson, Mats
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik. Linköpings universitet, Tekniska högskolan.
    Dannetun, Helen
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik. Linköpings universitet, Tekniska högskolan.
    Hydrogen interaction with Pt- and PdMIS devices2005Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 98, nr 1Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Hydrogen-sensitive Pd–SiO2–Si and Pt–SiO2–Si metal–insulator–semiconductor (MIS) devices have been studied in ultrahigh vacuum in the temperature range of 223–523 K. Adsorption/absorption of hydrogen occurs at the metal surface, in the metal bulk, and at the metal–insulator interface. The sensor signal, caused by hydrogen adsorption at the interface, shows a logarithmic dependence on the applied hydrogen pressure. The Pt-MIS device, which is fully functional at atmospheric pressures, is sensitive to changes in hydrogen pressure down to the 10−12-Torr scale. We propose that the interface adsorption follows a so-called Temkin isotherm with an interface heat of adsorption that varies with hydrogen coverage as ΔHi0(1−aθ). The initial heat of adsorption ΔHi0 is determined to 0.78 eV/hydrogen atom. The adsorption potential at the external Pt surface is found to be 0.45 eV/hydrogen atom. These values were obtained by modeling the hydrogen interaction with the MIS devices and fitting the model to a number of experimental results. Also studies of Pd-based devices were performed and compared with Pt. The hydrogen adsorption on the metal surface, previously treated as a first-order process on Pd, is shown to follow a second-order process. Qualitatively the results from the Pd- and Pt-MIS devices agree. Quantitatively there are differences. The hydrogen sensitivity of the Pt-MIS device is only approximately one-third compared to that of the Pd-MIS structure. This agrees with the result that the concentration of available hydrogen adsorption sites at the Pt–SiO2 interface is approximately 7×1017 m−2 whereas the concentrations of sites at the Pd–SiO2 interface is roughly three times larger (2×1018 m−2). An estimate of the size of the dipole moments (0.6–0.7 D) implies that the interface hydrogen atoms are strongly polarized. Differences are also observed in the microstructure of the metal films. Atomic force microscopy results show that the Pd surface reconstructs during H2–O2 exposures, while the Pt surface shows no such change at these temperatures.

  • 227.
    Sanz, Ruy
    et al.
    CNR IMM, Italy.
    Romano, Lucia
    University of Catania, Italy.
    Zimbone, Massimo
    CNR IMM, Italy.
    Antonietta Buccheri, Maria
    CNR IMM, Italy.
    Scuderi, Viviana
    CNR IMM, Italy.
    Impellizzeri, Giuliana
    CNR IMM, Italy.
    Scuderi, Mario
    CNR IMM, Italy.
    Nicotra, Giuseppe
    CNR IMM, Italy.
    Jensen, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Privitera, Vittorio
    CNR IMM, Italy.
    UV-black rutile TiO2: An antireflective photocatalytic nanostructure2015Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 117, nr 7, s. 074903-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This work presents an experimental study on the specific quantitative contributions of antireflective and effective surface areas on the photocatalytic and antibacterial properties of rutile TiO2 nanospikes. They are studied when continuously distributed over the whole surface and when integrated into well-defined microstructures. The nanospikes were produced following MeV ion beam irradiation of bulk rutile TiO2 single crystals and subsequent chemical etching. The ion beam irradiation generated embedded isolated crystalline nanoparticles inside an etchable amorphous TiO2 layer, and nanospikes fixed to the not etchable TiO2 bulk substrate. The produced nanospikes are shown to resist towards aggressive chemical environments and act as an efficient UV antireflective surface. The photocatalytic activity experiments were performed under the ISO 10678: 2010 protocol. The photonic and quantum efficiency are reported for the studied samples. The combined micro-and nanostructured surface triples the photonic efficiency compared to the initial flat surface. Results also revealed that the antireflective effect, due to the nanostructuring, is the dominating factor compared to the increase of surface area, for the observed photocatalytic response. The obtained results may be taken as a general strategy to design and precisely evaluate photoactive nanostructures. (C) 2015 AIP Publishing LLC.

  • 228.
    Sarakinos, Kostas
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanodesign. Linköpings universitet, Tekniska fakulteten.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Elofsson, Viktor
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanodesign. Linköpings universitet, Tekniska fakulteten.
    Magnfält, Daniel
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska fakulteten.
    Högberg, Hans
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Alling, Björn
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Max Planck Institute Eisenforsch GmbH, Germany.
    Theoretical and experimental study of metastable solid solutions and phase stability within the immiscible Ag-Mo binary system2016Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 119, nr 9, s. 095303-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Metastable solid solutions are phases that are synthesized far from thermodynamic equilibrium and offer a versatile route to design materials with tailor-made functionalities. One of the most investigated classes of metastable solid solutions with widespread technological implications is vapor deposited ternary transition metal ceramic thin films (i.e., nitrides, carbides, and borides). The vapor-based synthesis of these ceramic phases involves complex and difficult to control chemical interactions of the vapor species with the growing film surface, which often makes the fundamental understanding of the composition-properties relations a challenging task. Hence, in the present study, we investigate the phase stability within an immiscible binary thin film system that offers a simpler synthesis chemistry, i.e., the Ag-Mo system. We employ magnetron co-sputtering to grow Ag1-xMox thin films over the entire composition range along with x-ray probes to investigate the films structure and bonding properties. Concurrently, we use density functional theory calculations to predict phase stability and determine the effect of chemical composition on the lattice volume and the electronic properties of Ag-Mo solid solutions. Our combined theoretical and experimental data show that Mo-rich films (x >= similar to 0.54) form bcc Mo-Ag metastable solid solutions. Furthermore, for Ag-rich compositions (x <= similar to 0.21), our data can be interpreted as Mo not being dissolved in the Ag fcc lattice. All in all, our data show an asymmetry with regards to the mutual solubility of Ag and Mo in the two crystal structures, i.e., Ag has a larger propensity for dissolving in the bcc-Mo lattice as compared to Mo in the fcc-Ag lattice. We explain these findings in light of isostructural short-range clustering that induces energy difference between the two (fcc and bcc) metastable phases. We also suggest that the phase stability can be explained by the larger atomic mobility of Ag atoms as compared to that of Mo. The mechanisms suggested herein may be of relevance for explaining phase stability data in a number of metastable alloys, such as ternary transition metal-aluminum-nitride systems. (C) 2016 AIP Publishing LLC.

  • 229.
    Sarakinos, Kostas
    et al.
    Materials Chemistry, RWTH Aachen University, Germany.
    Music, D.
    RWTH Aachen University, Germany.
    Mraz, S.
    RWTH Aachen University, Germany.
    To Baben, M.
    RWTH Aachen University, Germany.
    Jiang, K.
    RWTH Aachen University, Germany.
    Nahif, F.
    RWTH Aachen University, Germany.
    Braun, A.
    RWTH Aachen University, Germany.
    Zilkens, C.
    RWTH Aachen University, Germany.
    Konstantinidis, S.
    University of Mons, Belgium.
    Renaux, F.
    Materia Nova Research Center, Mons, Belgium .
    Cossement, D.
    Materia Nova Research Center, Mons, Belgium .
    Munnik, F.
    Forschungszentrum Dresden Rossendorf, Germany.
    Schneider, J. M.
    RWTH Aachen University, Germany.
    On the phase formation of sputtered hafnium oxide and oxynitride films2010Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 108, nr 1, s. 014904-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Hafnium oxynitride films are deposited from a Hf target employing direct current magnetron sputtering in an Ar-O(2)-N(2) atmosphere. It is shown that the presence of N(2) allows for the stabilization of the transition zone between the metallic and the compound sputtering mode enabling deposition of films at well defined conditions of target coverage by varying the O(2) partial pressure. Plasma analysis reveals that this experimental strategy facilitates control over the flux of the O(-) ions which are generated on the oxidized target surface and accelerated by the negative target potential toward the growing film. An arrangement that enables film growth without O(-) ion bombardment is also implemented. Moreover, stabilization of the transition sputtering zone and control of the O(-) ion flux without N(2) addition is achieved employing high power pulsed magnetron sputtering. Structural characterization of the deposited films unambiguously proves that the phase formation of hafnium oxide and hafnium oxynitride films with the crystal structure of HfO(2) is independent from the O(-) bombardment conditions. Experimental and theoretical data indicate that the presence of vacancies and/or the substitution of O by N atoms in the nonmetal sublattice favor the formation of the cubic and/or the tetragonal HfO(2) crystal structure at the expense of the monoclinic HfO(2) one.

  • 230. Schifano, R.
    et al.
    Vinattieri, A.
    Department of Physics, University of Florence, Via Sansone 1, I-50019 Sesto Fiorentino, Italy.
    Bruzzi, M.
    Department of Energetics, Istituto Nazionale di Física Nucleare (INFN), University of Florence, Via di Santa Marta 3, I-50139 Florence, Italy.
    Miglio, S.
    Department of Energetics, Istituto Nazionale di Física Nucleare (INFN), University of Florence, Via di Santa Marta 3, I-50139 Florence, Italy.
    Lagomarsino, S.
    Department of Energetics, Istituto Nazionale di Física Nucleare (INFN), University of Florence, Via di Santa Marta 3, I-50139 Florence, Italy.
    Sciortino, S.
    Department of Energetics, Istituto Nazionale di Física Nucleare (INFN), University of Florence, Via di Santa Marta 3, I-50139 Florence, Italy.
    Nava, F.
    Department of Physics, University of Modena, Via Campi 213A, I-41100 Modena, Italy.
    Electrical and optical characterization of 4H-SiC diodes for particle detection2005Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 97, nr 10, s. 103539-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The electronic and optical properties of several (medium to high quality) 4H-SiC epitaxial sensors for particle detection have been studied. The samples are n -doped Schottky diodes with different nitrogen concentrations (6× 1013 cm-3 -5× 1015 cm-3) and thicknesses (20-40 µm). A full electrical and optical characterization has been performed by capacitance versus voltage measurements and near-band-edge low-temperature photoluminescence. The effective doping along the epilayer and the depletion width have been determined and data are consistent with the charge collection efficiency characterization performed with a minimum ionizing ? -source. All the investigated samples exhibit a 100% collection efficiency. In particular, the best samples yield a highly reproducible signal, well separated from the pedestal. Photoluminescence results show a linear relationship between the effective doping and the ratio of nitrogen-bound excitonic emission (Q0) and free excitonic line (I76), in agreement with a previous work on 4H-SiC with a higher doping concentration [I. G. Ivanov, C. Hallin, A. Henry, O. Kordina, and E. Janzn, J. Appl. Phys. 80, 3504 (1996)]. Moreover we show that the dependence of the major spectral features as a function of the penetration depth of the exciting laser beam can quantitatively provide information on substrate contribution to the photoluminescence. In conclusion, we bring evidence that a detailed characterization of SiC-based detectors, by all optical techniques, yields an accurate value for the net doping and gives a qualitative information on the epilayer thickness prior to any electrical wafer tests. © 2005 American Institute of Physics.

  • 231.
    Schmidt, Susann
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Czigany, Zs
    Hungarian Academic Science, Hungary .
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Jensen, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Ion mass spectrometry investigations of the discharge during reactive high power pulsed and direct current magnetron sputtering of carbon in Ar and Ar/N-22012Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 112, nr 1, s. 013305-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ion mass spectrometry was used to investigate discharges formed during high power impulse magnetron sputtering (HiPIMS) and direct current magnetron sputtering (DCMS) of a graphite target in Ar and Ar/N-2 ambient. Ion energy distribution functions (IEDFs) were recorded in time-averaged and time-resolved mode for Ar+, C+, N-2(+), N+, and CxNy+ ions. An increase of N-2 in the sputter gas (keeping the deposition pressure, pulse width, pulse frequency, and pulse energy constant) results for the HiPIMS discharge in a significant increase in C+, N+, and CN+ ion energies. Ar+, N-2(+), and C2N+ ion energies, in turn, did not considerably vary with the changes in working gas composition. The HiPIMS process showed higher ion energies and fluxes, particularly for C+ ions, compared to DCMS. The time evolution of the plasma species was analyzed for HiPIMS and revealed the sequential arrival of working gas ions, ions ejected from the target, and later during the pulse-on time molecular ions, in particular CN+ and C2N+. The formation of fullerene-like structured CNx thin films for both modes of magnetron sputtering is explained by ion mass-spectrometry results and demonstrated by transmission electron microscopy as well as diffraction.

  • 232.
    Schmidt, Susann
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Hänninen, Tuomas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Wissting, Jonas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad optik. Linköpings universitet, Tekniska fakulteten.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Goebbels, N.
    IHI Ionbond AG, Switzerland.
    Santana, A.
    IHI Ionbond AG, Switzerland.
    Tobler, M.
    IHI Ionbond AG, Switzerland.
    Högberg, Hans
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    SiNx coatings deposited by reactive high power impulse magnetron sputtering: Process parameters influencing the residual coating stress2017Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 121, nr 17, artikkel-id 171904Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The residual coating stress and its control is of key importance for the performance and reliability of silicon nitride (SiNx) coatings for biomedical applications. This study explores the most important deposition process parameters to tailor the residual coating stress and hence improve the adhesion of SiNx coatings deposited by reactive high power impulse magnetron sputtering (rHiPIMS). Reactive sputter deposition and plasma characterization were conducted in an industrial deposition chamber equipped with pure Si targets in N-2/Ar ambient. Reactive HiPIMS processes using N-2-to-Ar flow ratios of 0 and 0.28-0.3 were studied with time averaged positive ion mass spectrometry. The coatings were deposited to thicknesses of 2 mu m on Si(001) and to 5 mu m on polished CoCrMo disks. The residual stress of the X-ray amorphous coatings was determined from the curvature of the Si substrates as obtained by X-ray diffraction. The coatings were further characterized by X-ray photoelectron spectroscopy, scanning electron microscopy, and nano-indentation in order to study their elemental composition, morphology, and hardness, respectively. The adhesion of the 5 mu m thick coatings deposited on CoCrMo disks was assessed using the Rockwell C test. The deposition of SiNx coatings by rHiPIMS using N-2-to-Ar flow ratios of 0.28 yield dense and hard SiNx coatings with Si/N ratios amp;lt; 1. The compressive residual stress of up to 2.1 GPa can be reduced to 0.2 GPa using a comparatively high deposition pressure of 600 mPa, substrate temperatures below 200 degrees C, low pulse energies of amp;lt; 2.5 Ws, and moderate negative bias voltages of up to 100 V. These process parameters resulted in excellent coating adhesion (ISO 0, HF1) and a low surface roughness of 14 nm for coatings deposited on CoCrMo. (C) 2017 Author(s).

  • 233.
    Schoche, S.
    et al.
    University of Nebraska, NE 68588 USA.
    Hofmann, Tino
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten. University of Nebraska, NE 68588 USA.
    Nilsson, Daniel
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Kakanakova-Gueorguie, Anelia
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Kuhne, Philipp
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Lorenz, K.
    University of Lisbon, Portugal.
    Schubert, Mathias
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten. University of Nebraska, NE 68588 USA; Leibniz Institute Polymer Research Dresden, Germany.
    Darakchieva, Vanya
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten.
    Infrared dielectric functions, phonon modes, and free-charge carrier properties of high-Al-content AlxGa1-xN alloys determined by mid infrared spectroscopic ellipsometry and optical Hall effect2017Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 121, nr 20, artikkel-id 205701Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report on the analysis of a combined mid-infrared spectroscopic ellipsometry and mid-infrared optical Hall effect investigation of wurtzite structure c-plane oriented, crack-free, single crystalline, and high-Al-content AlxGa1-xN layers on 4H-SiC. For high-Al-content AlxGa1-xN, a two mode behavior is observed for both transverse and longitudinal branches of the infrared-active modes with E-1 symmetry, while a single mode behavior is found for the longitudinal modes with A1(LO) symmetry. We report their mode dependencies on the Al content. We determine and discuss static and high frequency dielectric constants depending on x. From the analysis of the optical Hall effect data, we determine the effective mass parameter in high-Al-content AlxGa1-xN alloys and its composition dependence. Within the experimental uncertainty limits, the effective mass parameters are found isotropic, which depend linearly on the Al content. The combination of all data permits the quantification of the free electron density N and mobility parameters mu. Published by AIP Publishing.

  • 234.
    Schöche, S.
    et al.
    University of Nebraska-Lincoln,USA .
    Hofmann, T.
    University of Nebraska-Lincoln, USA .
    Darakchieva, Vanya
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Sedrine, N. Ben
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Wang, X.
    Peking University, Peoples R China .
    Yoshikawa, A.
    Chiba University, Japan .
    Schubert, M.
    University of Nebraska-Lincoln, USA .
    Infrared to vacuum-ultraviolet ellipsometry and optical Hall-effect study of free-charge carrier parameters in Mg-doped InN2013Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 113, nr 1, s. 013502-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Infrared to vacuum-ultraviolet spectroscopic ellipsometry and far-infrared optical Hall-effect measurements are applied to conclude on successful p-type doping of InN films. A representative set of In-polar Mg-doped InN films with Mg concentrations ranging from 1.2 x 10(16) cm(-3) to 3.9 x 10(21) cm(-3) is investigated. The data are compared and discussed in dependence of the Mg concentration. Differences between n-type and p-type conducting samples are identified and explained. p-type conductivity in the Mg concentration range between 1.1 x 10(18) cm(-3) and 2.9 x 10(19) cm(-3) is indicated by the appearance of a dip structure in the infrared spectral region related to a loss in reflectivity of p-polarized light as a consequence of reduced LO phonon plasmon coupling, by vanishing free-charge carrier induced birefringence in the optical Hall-effect measurements, and by a sudden change in phonon-plasmon broadening behavior despite continuous change in the Mg concentration. By modeling the near-infrared-to-vacuum-ultraviolet ellipsometry data, information about layer thickness, electronic interband transitions, as well as surface roughness is extracted in dependence of the Mg concentration. A parameterized model that accounts for the phonon-plasmon coupling is applied for the infrared spectral range to determine the free-charge carrier concentration and mobility parameters in the doped bulk InN layer as well as the GaN template and undoped InN buffer layer. The optical Hall-effect best-match model parameters are consistent with those obtained from infrared ellipsometry analysis.

  • 235. Seppanen, T.
    et al.
    Hultman, Lars
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Birch, Jens
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Beckers, M.
    Institute for Ion Beam Physics and Materials Science (FWI), Forschungszentrum Rossendorf e.V. (FZR), P.O. Box 510119, 01314 Dresden, Germany.
    Kreissig, U.
    Institute for Ion Beam Physics and Materials Science (FWI), Forschungszentrum Rossendorf e.V. (FZR), P.O. Box 510119, 01314 Dresden, Germany.
    Deviations from Vegard's rule in Al1-xInxN (0001) alloy thin films grown by magnetron sputter epitaxy2007Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 101, nr 4Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Al1-xInxN (0001) thin films of the pseudobinary AlN-InN system were grown epitaxially onto (111)-oriented MgO wafers with seed layers of Ti1-y Zry N by dual direct current magnetron sputtering under ultrahigh vacuum conditions. The relaxed film c -axis lattice parameters determined by x-ray diffraction were studied as a function of composition in the range of 0.07

  • 236.
    Seppänen, Timo
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Persson, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Hultman, Lars
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Birch, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Radnoczi, G. Z.
    Magnetron sputter epitaxy of wurtzite Al1-xInxN (0.1 x 0.9) by Dual Reactive DC Magnetron Sputter Deposition2005Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 97, s. 83503-1-83503-9Artikkel i tidsskrift (Fagfellevurdert)
  • 237.
    Seppänen, Timo
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Persson, Per
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Hultman, Lars
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Birch, Jens
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Radnoczi, G.Z.
    Radnóczi, G.Z., Research Institute for Technical Physics and Materials Science (MFA), Hungarian Academy of Sciences, H-1525 Budapest, P.O. Box 49, Hungary.
    Magnetron sputter epitaxy of wurtzite Al1-x Inx N (0.12005Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 97, nr 8, s. 083503-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ternary wurtzite Al1-x Inx N thin films with compositions throughout the miscibility gap have been grown onto seed layers of TiN and ZrN by magnetron sputter epitaxy (MSE) using dual reactive direct current magnetron sputter deposition under ultra high vacuum conditions. The film compositions were calculated using Vegard's law from lattice parameters determined by x-ray diffraction (XRD). XRD showed that single-phase Al1-x Inx N alloy films in the wurtzite structure with [0.10 TiN,ZrN <110>. At higher substrate temperatures almost pure AlN was formed. The microstructure of the films was also investigated by high-resolution electron microscopy. A columnar growth mode with epitaxial column widths from 10 to 200 nm was observed. Rocking curve full-width-at-half-maximum measurements revealed highly stressed lattices for growth onto TiN at 600°C. Pseudobinary MSE growth phase field diagrams for Al1-x Inx N onto ZrN and TiN were established for substrate temperatures up to 1000°C. Large regimes for single-phase solid solutions were thus identified with In being the diffusing species. © 2005 American Institute of Physics.

  • 238.
    Severin, D.
    et al.
    Aachen University, Germany.
    Sarakinos, Kostas
    Institute of Physics (IA), RWTH Aachen University, Germany.
    Kappertz, O.
    Uppsala University, Sweden.
    Pflug, A.
    Fraunhofer IST, Germany.
    Wuttig, M.
    Aachen University, Germany.
    Tailoring of structure formation and phase composition in reactively sputtered zirconium oxide films using nitrogen as an additional reactive gas2008Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 103, nr 8, s. 083306-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The structure of ZrO(2) films has been controlled during reactive sputtering in an argon/oxygen atmosphere by adding an amount of nitrogen gas to the process. Depending on the deposition conditions, amorphous, cubic, or monoclinic films have been obtained without any additional substrate heating. The resulting film structure is explained in terms of the control of fast negative oxygen ions generated at the target surface and accelerated toward the growing film. Furthermore, the nitrogen addition leads to a pronounced stabilization of the plasma discharge and fewer arcing events, while the incorporation of nitrogen atoms in the growing film is very small.

  • 239.
    Shin, C.-S.
    et al.
    Materials Science Department, Frederick Seitz Mat. Res. Laboratory, University of Illinois, 104 South Goodwin Avenue, Urbana, IL 61801, United States.
    Gall, D.
    Materials Science Department, Frederick Seitz Mat. Res. Laboratory, University of Illinois, 104 South Goodwin Avenue, Urbana, IL 61801, United States.
    Kim, Y.-W.
    Materials Science Department, Frederick Seitz Mat. Res. Laboratory, University of Illinois, 104 South Goodwin Avenue, Urbana, IL 61801, United States.
    Desjardins, P.
    Materials Science Department, Frederick Seitz Mat. Res. Laboratory, University of Illinois, 104 South Goodwin Avenue, Urbana, IL 61801, United States.
    Petrov, I.
    Materials Science Department, Frederick Seitz Mat. Res. Laboratory, University of Illinois, 104 South Goodwin Avenue, Urbana, IL 61801, United States.
    Greene, J.E.
    Materials Science Department, Frederick Seitz Mat. Res. Laboratory, University of Illinois, 104 South Goodwin Avenue, Urbana, IL 61801, United States.
    Odén, Magnus
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material.
    Hultman, Lars
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Epitaxial NaCl structure d-TaNx(001): Electronic transport properties, elastic modulus, and hardness versus N/Ta ratio2001Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 90, nr 6, s. 2879-2885Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    While metastable Bl-NaCl-structure d-TaNx. is presently used in a variety of hard coating, wear-resistant, and diffusion barrier applications, it is a complex material exhibiting a wide single-phase field, x?0.94-1.37, and little is known about its fundamental properties. Here, we report physical properties of epitaxial d-TaNx. layers grown as a function of x on MgO(00) by ultrahigh vacuum reactive magnetron sputter deposition. The room-temperature resistivity (? = 225 µO cm), hardness (H = 30.9 GPa), and elastic modulus (E = 455 GPa) of d-TaNx(001) are independent of x over the range 0.94-1.22. However, changes in the electronic structure associated with increasing x>1.22 lead to an increase in ? with a decrease in H and E. All d-TaNx(001) layers exhibit negative temperature coefficients of resistivity between 20 and 400 K due to weak carrier localization. d-TaNx is superconducting with the highest critical temperature, 8.45 K, obtained for layers with the lowest N/Ta ratio, x=0.94. Based upon the above results, combined with the fact that the relaxed lattice constant a0 shows only a very weak dependence on x, we propose that the wide phase field in d-TaNx is due primarily to antisite substitutions of Ta on N (and N on Ta) sites, rather than to cation and anion vacancies. To first order, antisite substitutions in TaNx are isoelectronic and hence have little effect on charge carrier density. At sufficiently high N/Ta ratios, however, simple electron-counting arguments are no longer valid since large deviations from stoichiometry alter the character of the band structure itself. © 2001 American Institute of Physics.

  • 240.
    Sillassen, M.
    et al.
    University of Aarhus, Department of Physics and Astronomy and Interdisciplinary Nanoscience Center (iNANO).
    Eklund, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Sridharan, M.
    University of Aarhus, Department of Physics and Astronomy and Interdisciplinary Nanoscience Center (iNANO).
    Pryds, N.
    Technical University of Denmark, Riso National Laboratory for Sustainable Energy.
    Bonanos, N.
    Technical University of Denmark, Riso National Laboratory for Sustainable Energy.
    Bottiger, J.
    University of Aarhus, Department of Physics and Astronomy and Interdisciplinary Nanoscience Center (iNANO).
    Ionic conductivity and thermal stability of magnetron-sputtered nanocrystalline yttria-stabilized zirconia2009Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 105, nr 10, s. 104907-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Thermally stable, stoichiometric, cubic yttria-stabilized zirconia (YSZ) thin-film electrolytes have been synthesized by reactive pulsed dc magnetron sputtering from a Zr-Y (80/20 at. %) alloy target. Films deposited at floating potential had a ‹111› texture. Single-line profile analysis of the 111 x-ray diffraction peak yielded a grain size of ~20 nm and a microstrain of ~2% regardless of deposition temperature. Films deposited at 400 °C and selected bias voltages in the range from -70 to -200 V showed a reduced grain size for higher bias voltages, yielding a grain size of ~6 nm and a microstrain of ~2.5% at bias voltages of -175 and -200 V with additional incorporation of argon. The films were thermally stable; very limited grain coarsening was observed up to an annealing temperature of 800 °C. Temperature-dependent impedance spectroscopy analysis of the YSZ films with Ag electrodes showed that the in-plane ionic conductivity was within one order of magnitude higher in films deposited with substrate bias corresponding to a decrease in grain size compared to films deposited at floating potential. This suggests that there is a significant contribution to the ionic conductivity from grain boundaries. The activation energy for oxygen ion migration was determined to be between 1.14 and 1.30 eV.

     

  • 241.
    Slomski, M.
    et al.
    North Carolina State University, NC 27695 USA.
    Blumenschein, N.
    North Carolina State University, NC 27695 USA.
    Paskov, Plamen
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska fakulteten. North Carolina State University, NC 27695 USA.
    Muth, J. F.
    North Carolina State University, NC 27695 USA.
    Paskova, T.
    North Carolina State University, NC 27695 USA.
    Anisotropic thermal conductivity of beta-Ga2O3 at elevated temperatures: Effect of Sn and Fe dopants2017Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 121, nr 23, artikkel-id 235104Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The thermal conductivity of undoped, Sn-doped, and Fe-doped beta-Ga2O3 bulk crystals was measured by the 3 omega technique in the temperature range of 295-410 K. A unique approach for extracting the thermal conductivity along the lateral and transverse heat flow directions was used in order to determine the thermal conductivity along different crystallographic directions. The data analysis at room temperature confirmed the expected anisotropy of the thermal conductivity of beta-Ga2O3, revealing the highest value of similar to 29 W/m K in the [010] direction. The thermal conductivity of the Sn-doped and Fe-doped beta-Ga2O3 samples was found to be lower than that of the undoped samples due to the enhanced phonon-impurity scattering contribution, which reduces the thermal conductivity. This tendency was maintained for the thermal conductivity at elevated temperatures. The thermal conductivity in all samples decreased with increasing temperature, but the slope of the temperature dependence was found to depend on both the doping and the crystallographic orientation. Published by AIP Publishing.

  • 242.
    Son Phuong, Le
    et al.
    Center for Nano Materials and Technology, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan.
    Tuan Quy, Nguyen
    Center for Nano Materials and Technology, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan.
    Hong-An, Shih
    Center for Nano Materials and Technology, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan.
    Masahiro, Kudo
    Center for Nano Materials and Technology, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan.
    Toshi-kazu, Suzuki
    Center for Nano Materials and Technology, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan.
    Low-frequency noise in AlN/AlGaN/GaN metal-insulator-semiconductor devices: A comparison with Schottky devices.2014Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 116, nr 5, s. 8artikkel-id 054510Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have systematically investigated low-frequency noise (LFN) in AlN/AlGaN/GaN metalinsulator- semiconductor (MIS) devices, where the AlN gate insulator layer was sputteringdeposited on the AlGaN surface, in comparison with LFN in AlGaN/GaN Schottky devices. By measuring LFN in ungated two-terminal devices and heterojunction field-effect transistors (HFETs), we extracted LFN characteristics in the intrinsic gated region of the HFETs. Although there is a bias regime of the Schottky-HFETs in which LFN is dominated by the gate leakage current, LFN in theMIS-HFETs is always dominated by only the channel current. Analyzing the channel-current-dominated LFN, we obtained Hooge parameters α for the gated region as a function of the sheet electron concentration ns under the gate. In a regime of small ns, both the MIS- and Schottky-HFETs exhibit α ∝ ns–1. On the other hand, in a middle ns regime of the MIS-HFETs, α decreases rapidly like ns–ξ with ξ~2-3, which is not observed for the Schottky- HFETs. In addition, we observe strong increase in α ∝ ns3 in a large ns regime for both the MIS- and Schottky-HFETs. [ABSTRACT FROM AUTHOR]

  • 243.
    Son Tien, Nguyen
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Trinh, Xuan Thang
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Gällström, Andreas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Leone, Stefano
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Kordina, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Szasz, Krisztian
    Hungarian Academic Science, Hungary .
    Ivady, Viktor
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Gali, Adam
    Hungarian Academic Science, Hungary Budapest University of Technology and Econ, Hungary .
    Electron paramagnetic resonance and theoretical studies of Nb in 4H- and 6H-SiC2012Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 112, nr 8, s. 083711-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    High purity silicon carbide (SiC) materials are of interest from high-power high temperature applications across recent photo-voltaic cells to hosting solid state quantum bits, where the tight control of electrically, optically, and magnetically active point defects is pivotal in these areas. 4H- and 6H-SiC substrates are grown at high temperatures and the incorporation of transition metal impurities is common. In unintentionally Nb-doped 4H- and 6H-SiC substrates grown by high-temperature chemical vapor deposition, an electron paramagnetic resonance (EPR) spectrum with C-1h symmetry and a clear hyperfine (hf) structure consisting of ten equal intensity hf lines was observed. The hf structure can be identified as due to the interaction between the electron spin S - 1/2 and the nuclear spin of Nb-93. Additional hf structures due to the interaction with three Si neighbors were also detected. In 4H-SiC, a considerable spin density of similar to 37.4% was found on three Si neighbors, suggesting the defect to be a complex between Nb and a nearby carbon vacancy (V-C). Calculations of the Nb-93 and Si-29 hf constants of the neutral Nb on Si site, Nb-Si(0), and the Nb-vacancy defect, NbSiVC0, support previous reported results that Nb preferentially forms an asymmetric split-vacancy (ASV) defect. In both 4H- and 6H-SiC, only one Nb-related EPR spectrum has been observed, supporting the prediction from calculations that the hexagonal-hexagonal defect configuration of the ASV complex is more stable than others.

  • 244.
    Spetz, Anita
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik. Linköpings universitet, Tekniska högskolan.
    Armgarth, M.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik. Linköpings universitet, Tekniska högskolan.
    Lundström, Ingemar
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik. Linköpings universitet, Tekniska högskolan.
    HYDROGEN AND AMMONIA RESPONSE OF METAL-SILICON DIOXIDE-SILICON STRUCTURES WITH THIN PLATINUM GATES1988Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 64, nr 3, s. 1274-1283Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The hydrogen and ammonia sensitivity of metal‐oxide‐semiconductor (MOS) structures with platinum gates between 3 and 70 nm thick was investigated. The response to these gases was measured as a shift in the capacitance‐voltage (CV) curve of the MOS structure along the voltage axis. The measurements were made at an elevated temperature, mainly at 150 °C, where chemical reactions take place on the surface of the catalytic metal. The main purpose of the investigation was to determine if hydrogen and ammonia are detected by similar mechanisms. It is concluded that hydrogen molecules are dissociated and hydrogen atoms give rise to a dipole layer at the metal‐oxide interface, similar to the behavior of hydrogen in hydrogen sensitive MOS structures with thick catalytic metal, normally Pd, gates. Ammonia, on the other hand, appears to be detected through surface potential changes of the Pt film, which are capacitively coupled to the semiconductor surface through voids in the thin metal film.

  • 245.
    Stehr, Jan Eric
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Funktionella elektroniska material. Linköpings universitet, Tekniska fakulteten.
    Chen, Weimin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Funktionella elektroniska material. Linköpings universitet, Tekniska fakulteten.
    Svensson, B. G.
    University of Oslo, Norway.
    Buyanova, Irina
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Funktionella elektroniska material. Linköpings universitet, Tekniska fakulteten.
    Thermal stability of the prominent compensating (Al-Zn-V-Zn) center in ZnO2016Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 119, nr 10, s. 105702-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electron paramagnetic resonance spectroscopy is used to investigate the thermal stability of the Aluminum-Zinc vacancy (Al-Zn-V-Zn) complex created in bulk single crystalline ZnO by room temperature electron irradiation with an energy of 1.2 MeV. Two different stages in the annealing process at 160 and 250 degrees C with apparent activation energies of E-A1 = 1.5 +/- 0.2 eV and E-A2 = 1.9 +/- 0.2 eV, respectively, are observed. The second stage leads to the complete annealing out of the (Al-Zn-V-Zn) complex and is accompanied by restoration of the concentration of the AlZn shallow donor centers to its initial value in as-grown (i.e., not irradiated) material. The obtained results prove that the (Al-Zn-V-Zn) complex is the dominant acceptor responsible for compensation of n-type-dopants in the studied Al-containing ZnO samples. (C) 2016 AIP Publishing LLC.

  • 246.
    Stehr, Jan Eric
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Funktionella elektroniska material. Linköpings universitet, Tekniska högskolan.
    Hofmann, D. M.
    University of Giessen, Germany .
    Meyer, B. K.
    University of Giessen, Germany .
    Electron paramagnetic resonance and photo-electron paramagnetic resonance investigation on the recharging of the substitutional nitrogen acceptor in ZnO2012Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 112, nr 10, s. 103511-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We investigated the substitutional nitrogen center in ZnO single crystals by electron paramagnetic resonance (EPR) and photo-EPR spectroscopy. Aside the three principle hyperfine lines due to the interaction of the N-0 (2p5) electron spin with the nitrogen nucleus (I = 1, natural abundance 99.6%), we identify additional satellite lines which arise from Delta m(S) = +/- 1 and Delta m(I) = +/- 1, +/- 2 transitions becoming allowed due to quadrupole interaction. The quadrupole coupling constant e(2)qQ/h is determined to -5.9 MHz with an asymmetry parameter of eta = 0.05. These values are somewhat different from those obtained for the nitrogen center in ZnO powders, but are closer to the theoretical calculations of Gallino et al. We further carefully investigated the photon induced recharging of the N centers. We determine the energy h nu required for the process N-O(-) + h nu -andgt; N-O(0) + e(cb)(-) to 2.1 +/- 0.05 eV, the dependence of the EPR signal intensity on the illumination time shows a mono-exponential behavior which gives evidence that a direct ionization process is monitored.

  • 247.
    Stehr, Jan Eric
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Funktionella elektroniska material. Linköpings universitet, Tekniska högskolan.
    Wang, Xingjun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Funktionella elektroniska material. Linköpings universitet, Tekniska högskolan.
    Filippov, Stanislav
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Funktionella elektroniska material. Linköpings universitet, Tekniska högskolan.
    Pearton, S J.
    University of Florida, FL USA .
    Gueorguiev Ivanov, Ivan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Chen, Weimin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Funktionella elektroniska material. Linköpings universitet, Tekniska högskolan.
    Buyanova, Irina
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Funktionella elektroniska material. Linköpings universitet, Tekniska högskolan.
    Defects in N, O and N, Zn implanted ZnO bulk crystals2013Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 113, nr 10, s. 103509-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Comprehensive characterization of defects formed in bulk ZnO single crystals co-implanted with N and Zn as well as N and O atoms is performed by means of optically detected magnetic resonance (ODMR) complemented by Raman and photoluminescence (PL) spectroscopies. It is shown that in addition to intrinsic defects such as Zn vacancies and Zn interstitials, several N-related defects are formed in the implanted ZnO. The prevailed configuration of the defects is found to depend on the choices of the co-implants and also the chosen annealing ambient. Specifically, co-implantation with O leads to the formation of (i) defects responsible for local vibrational modes at 277, 511, and 581 cm−1; (ii) a N-related acceptor with the binding energy of 160 ± 40 meV that is involved in the donor-acceptor pair emission at 3.23 eV; and (iii) a deep donor and a deep NO acceptor revealed from ODMR. Activation of the latter defects is found to require post-implantation annealing in nitrogen ambient. None of these defects are detected when N is co-implanted with Zn. Under these conditions, the dominant N-induced defects include a deep center responsible for the 3.3128 eV PL line, as well as an acceptor center of unknown origin revealed by ODMR. Formation mechanisms of the studied defects and their role in carrier recombination are discussed.

  • 248.
    Storasta, Liutauras
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik.
    Bergman, J.R.
    Janzén, Erik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik.
    Henry, Anne
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik.
    Lu, J.
    Materials Research Laboratory, Institute of Materials Science, Uppsala University, P.O. Box 538, SE-751 21 Uppsala, Sweden.
    Deep levels created by low energy electron Irradiation in 4H-SiC2004Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 96, nr 9, s. 4909-4915Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    With low energy electron irradiation in the 80-250 keV range, we were able to create only those intrinsic defects related to the initial displacements of carbon atoms in the silicon carbide lattice. Radiation induced majority and minority carrier traps were analyzed using capacitance transient techniques. Four electron traps (EH1, Z1/Z2, EH3, and EH7) and one hole trap (HS2) were detected in the measured temperature range. Their concentrations show linear increase with the irradiation dose, indicating that no divacancies or di-interstitials are generated. None of the observed defects was found to be an intrinsic defect-impurity complex. The energy dependence of the defect introduction rates and annealing behavior are presented and possible microscopic models for the defects are discussed. No further defects were detected for electron energies above the previously assigned threshold for the displacement of the silicon atom at 250 keV. © 2004 American Institute of Physics. 10.1063/1.1778819.

  • 249.
    Strokan, N.B.
    et al.
    A. F. Ioffe Phys.-Tekhnical Inst., Polytekhnichaskaja 26, 194021 St. Petersburg, Russian Federation.
    Ivanov, A.M.
    A. F. Ioffe Phys.-Tekhnical Inst., Polytekhnichaskaja 26, 194021 St. Petersburg, Russian Federation.
    Savkina, N.S.
    A. F. Ioffe Phys.-Tekhnical Inst., Polytekhnichaskaja 26, 194021 St. Petersburg, Russian Federation.
    Strelchuk, A.M.
    A. F. Ioffe Phys.-Tekhnical Inst., Polytekhnichaskaja 26, 194021 St. Petersburg, Russian Federation.
    Lebedev, A.A.
    A. F. Ioffe Phys.-Tekhnical Inst., Polytekhnichaskaja 26, 194021 St. Petersburg, Russian Federation.
    Syväjärvi, Mikael
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik.
    Yakimova, Rositsa
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik.
    Detection of strongly and weakly ionizing radiation by triode structure based on SIC films2003Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 93, nr 9, s. 5714-5719Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The detection of strongly and weakly ionizing radiation by triode structure based on silicon carbide (SiC) films was discussed. The possibility of alpha particle spectrometry in spite of slow carrier transport via diffusion was demonstrated. Analysis showed that the signal generated by weakly ionizing radiation incident on a film had low amplitude.

  • 250.
    Sun, Jianwu
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Robert, T.
    Universite Montellier 2, France .
    Andreadou, A.
    Aristotle University of Thessaloniki, Greece .
    Mantzari, A.
    Aristotle University of Thessaloniki, Greece .
    Jokubavicius, Valdas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Yakimova, Rositsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Camassel, J.
    Universite Montellier 2, France.
    Juillaguet, S.
    Universite Montpellier 2, France.
    Polychroniadis, E. K.
    Aristotle University of Thessaloniki, Greece.
    Syväjärvi, Mikael
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Shockley-Frank stacking faults in 6H-SiC2012Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 111, s. 113527-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report on Shockley-Frank stacking faults (SFs) identified in 6H-SiC by a combination of low temperature photoluminescence (LTPL) and high resolution transmission electron microscopy (TEM). In the faulted area, stacking faults manifested as large photoluminescence emissions bands located in between the 6H-SiC signal (at ∼2.99 eV) and the 3C-SiC bulk-like one (at ∼2.39 eV). Each of the stacking fault related emission band had a four-fold structure coming from the TA, LA, TO, and LO phonon modes of 3C-SiC. Up to four different faults, with four different thickness of the 3C-SiC lamella, could be observed simultaneously within the extent of the laser excitation spot. From the energy of the momentum-conservative phonons, they were associated with excitonic energy gaps at Egx1 = 2.837 eV, Egx2 = 2.689 eV, Egx3 = 2.600 eV and Egx4 = 2.525 eV. In the same part where low temperature photoluminescence was performed, high resolution transmission electron microscopy measurements revealed stacking faults which, in terms of the Zhdanov notation, could be recognized as SFs (3, 4), (3, 5), (3, 6), (3, 7), (3, 9), (3, 11), (3, 16) and (3, 22), respectively. Among them stacking fault (3, 4) was the most common one, but a faulted region with a (4, 4) 8H-SiC like sequence was also found. Using a type II 6H/3C/6H quantum-well model and comparing with experimental results, we find that the photoluminescence emissions with excitonic band gaps at 2.837 eV (Egx1), 2.689 eV (Egx2), 2.600 eV (Egx3) and 2.525 eV (Egx4) come from SFs (3, 4), (3, 5), (3, 6) and (3, 7), respectively. A possible formation mechanism of these SFs is suggested, which involves a combination of Frank faults with Shockley ones. This provides a basic understanding of stacking faults in 6H-SiC and gives a rapid and non-destructive approach to identify SFs by low temperature photoluminescence.

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