liu.seSearch for publications in DiVA
Change search
Refine search result
1 - 48 of 48
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Ali, M.
    et al.
    Helsinki University of Technology (TKK), Micronova, Department of Micro and Nanosciences, P.O. Box 3500, FIN-02015 TKK, Finland.
    Svensk, Olle
    Helsinki University of Technology (TKK), Micronova, Department of Micro and Nanosciences, P.O. Box 3500, FIN-02015 TKK, Finland.
    Zhen, Z.
    Helsinki University of Technology (TKK), Micronova, Department of Micro and Nanosciences, P.O. Box 3500, FIN-02015 TKK, Finland.
    Suihkonen, S.
    Helsinki University of Technology (TKK), Micronova, Department of Micro and Nanosciences, P.O. Box 3500, FIN-02015 TKK, Finland.
    Törmä, P.T.
    Helsinki University of Technology (TKK), Micronova, Department of Micro and Nanosciences, P.O. Box 3500, FIN-02015 TKK, Finland.
    Lipsanen, H.
    Helsinki University of Technology (TKK), Micronova, Department of Micro and Nanosciences, P.O. Box 3500, FIN-02015 TKK, Finland.
    Sopanen, M.
    Helsinki University of Technology (TKK), Micronova, Department of Micro and Nanosciences, P.O. Box 3500, FIN-02015 TKK, Finland.
    Hjort, Klas
    Department of Engineering Sciences, Uppsala University, P.O. Box 534, SE-75121 Uppsala, Sweden.
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Reduced photoluminescence from InGaN/GaN multiple quantum well structures following 40 MeV iodine ion irradiation2009In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, ISSN 0921-4526, Vol. 404, no 23-24, p. 4925-4928Article in journal (Refereed)
    Abstract [en]

    The effects following ion irradiation of GaN-based devices are still limited. Here we present data on the photoluminescence (PL) emitted from InGaN/GaN multiple quantum well (MQW) structures, which have been exposed to 40 MeV I ion irradiation. The PL is reduced as a function of applied ion fluence, with essentially no PL signal left above 1011 ions/cm2. It is observed that even the ion fluences in the 109 ions/cm2 range have a pronounced effect on the photoluminescence properties of the MQW structures. This may have consequences concerning application of InGaN/GaN MQW’s in radiation-rich environments, in addition to defect build-up during ion beam analysis.

  • 2.
    Booker, Ian D.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Farkas, Ildiko
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Ivanov, Ivan G.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Ul Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Chloride-based SiC growth on a-axis 4H-€“SiC substrates2016In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 480, p. 23-25Article in journal (Refereed)
    Abstract [en]

    Abstract SiC has, during the last few years, become increasingly important as a power-device material for high voltage applications. The thick, low-doped voltage-supporting epitaxial layer is normally grown by CVD on 4° off-cut 4H–SiC substrates at a growth rate of 5 – 10 ÎŒ m / h using silane (SiH4) and propane (C3H8) or ethylene (C2H4) as precursors. The concentrations of epitaxial defects and dislocations depend to a large extent on the underlying substrate but can also be influenced by the actual epitaxial growth process. Here we will present a study on the properties of the epitaxial layers grown by a Cl-based technique on an a-axis (90° off-cut from c-direction) 4H–SiC substrate.

  • 3.
    Borlado, C R
    et al.
    Inst de Ciencia de Materiales de Madrid Madrid.
    Mompean, F J
    Inst de Ciencia de Materiales de Madrid Madrid.
    Peng, Ru
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Engineering Materials.
    Izquierdo, J
    IBERDROLA Madrid.
    de Luis, J
    IBERDROLA Madrid.
    Neutron strain scanning in bimetallic tubes: experimental and Monce Carlo simulation results2000In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 276-278, p. 907-908Article in journal (Refereed)
  • 4.
    Buyanova, Irina A.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials. Linköping University, The Institute of Technology.
    Chen, Weimin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Goldys, E.M.
    Division of Information and Communication Sciences, Macquarie University, Sydney, NSW, Australia.
    Phillips, M.R.
    Microstructural Analysis Unit, University of Technology, Sydney, NSW, Australia.
    Xin, H.P.
    Department of Electrical and Computer Engineering, University of California, San Diego, CA, United States.
    Tu, C.W.
    Department of Electrical and Computer Engineering, University of California, San Diego, CA, United States.
    Strain relaxation in GaNxP1-x alloy: Effect on optical properties2001In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 308-310, p. 106-109Article in journal (Refereed)
    Abstract [en]

    By using scanning electron microscopy and cathodoluminescence (CL), a decrease in radiative efficiency of GaNP alloy with increasing N content is seen due to the formation of structural defects. The defect formation is attributed to relaxation of tensile strain in the GaNP layer, which is lattice mismatched to GaP substrate. Several types of extended defects including dislocations, microcracks and pits are revealed in partly relaxed GaNxP1-x epilayers with x=1.9%, whereas coherently strained layers exhibit high crystalline quality for x up to 4%. According to the CL measurements, all extended defects act as competing, non-radiative channels leading to the observed strong decrease in the radiative efficiency. From CL mapping experiments, non-uniformity of strain distribution around the extended defects is partly responsible for the broadening of the photoluminescence (PL) spectra recorded in the macro-PL experiments. © 2001 Elsevier Science B.V. All rights reserved.

  • 5.
    Buyanova, Irina A
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials. Linköping University, The Institute of Technology.
    Hallberg, T
    Linkoping Univ, Dept Phys & Measurement Technol, S-58183 Linkoping, Sweden Swedish Def Res Estab, S-58111 Linkoping, Sweden Inst Solid State & Semicond Phys, Minsk 220072, Byelarus Univ Lund, S-22100 Lund, Sweden.
    Murin, LI
    Linkoping Univ, Dept Phys & Measurement Technol, S-58183 Linkoping, Sweden Swedish Def Res Estab, S-58111 Linkoping, Sweden Inst Solid State & Semicond Phys, Minsk 220072, Byelarus Univ Lund, S-22100 Lund, Sweden.
    Markevich, VP
    Linkoping Univ, Dept Phys & Measurement Technol, S-58183 Linkoping, Sweden Swedish Def Res Estab, S-58111 Linkoping, Sweden Inst Solid State & Semicond Phys, Minsk 220072, Byelarus Univ Lund, S-22100 Lund, Sweden.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Lindstrom, JL
    Effect of high-temperature electron irradiation on the formation of radiative defects in silicon1999In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 274, p. 528-531Article in journal (Refereed)
    Abstract [en]

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

  • 6.
    Buyanova, Irina A
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials. Linköping University, The Institute of Technology.
    Izadifard, Morteza
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Seppänen, Timo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Birch, Jens
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Chen, Weimin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Pearton, SJ
    Polimeni, A
    Capizzi, M
    Brandt, MS
    Bihler, C
    Hong, YG
    Tu, CW
    Unusual effects of hydrogen on electronic and lattice properties of GaNP alloys2006In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 376, p. 568-570Article in journal (Refereed)
    Abstract [en]

    Hydrogen incorporation is shown to cause passivation of various N-related localized states and partial neutralization of N-induced changes in the electronic structure of the GaNxP1-x alloys with x < 0.008. According to the performed X-ray diffraction measurements, the hydrogenation is also found to cause strong expansion of the GaNP lattice which even changes from a tensile strain in the as-grown GaNP epilayers to a compressive strain in the post-hydrogenated structures with the highest H concentration. By comparing results obtained using two types of hydrogen treatments, i.e. by implantation from a Kaufman source and by using a remote dc H plasma, the observed changes are shown to be inherent to H due to its efficient complexing with N atoms, whereas possible effects of implantation damage are only marginal. (c) 2005 Elsevier B.V. All rights reserved.

  • 7.
    Chubarov, M.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Pedersen, Henrik
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Filippov, Stanislav
    Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials. Linköping University, The Institute of Technology.
    Engelbrecht, J.A. A.
    Nelson Mandela Metropolitan University, South Africa .
    O'Connel, J.
    Nelson Mandela Metropolitan University, South Africa .
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Boron nitride: A new photonic material2014In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 439, p. 29-34Article in journal (Refereed)
    Abstract [en]

    Rhombohedral boron nitride (r-BN) layers were grown on sapphire substrate in a hot-wall chemical vapor deposition reactor. Characterization of these layers is reported in details. X-ray diffraction (XRD) is used as a routine characterization tool to investigate the crystalline quality of the films and the identification of the phases is revealed using detailed pole figure measurements. Transmission electron microscopy reveals stacking of more than 40 atomic layers. Results from Fourier Transform InfraRed (FTIR) spectroscopy measurements are compared with XRD data showing that FTIR is not phase sensitive when various phases of sp(2)-BN are investigated. XRD measurements show a significant improvement of the crystalline quality when adding silicon to the gas mixture during the growth; this is further confirmed by cathodoluminescence which shows a decrease of the defects related luminescence intensity.

  • 8.
    Colibaba, G. V
    et al.
    Moldova State Univ, Moldova.
    Avdonin, A.
    Polish Acad Sci, Poland.
    Shtepliuk, Ivan
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering. Frantsevich Inst Problems Mat Sci NASU, Ukraine.
    Caraman, M.
    Moldova State Univ, Moldova.
    Domagala, J.
    Polish Acad Sci, Poland.
    Inculet, I.
    Moldova State Univ, Moldova.
    Effects of impurity band in heavily doped ZnO:HCl2019In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 553, p. 174-181Article in journal (Refereed)
    Abstract [en]

    A comparative study of properties of ZnO:HCl single crystals obtained by various methods is presented. Characterization by photoluminescence, optical and electrical measurements in the wide temperature range has allowed to analyze the energy spectra of Cl-containing stable defects in ZnO. Presence of shallow Cl donors, deeper donor complexes, incorporating several Cl atoms or stable H-Cl pairs and presence of compensating deep acceptors, attributed to VznClo centers, are demonstrated. The presence of shallow donor impurity band, as well as strong dependence of its activation energy on the doping level is shown. The controversy of various models for estimation of this dependence is discussed. It is demonstrated, that 90% of this dependence is caused by feature of temperature dependence of Hall coefficient related to conductive impurity band, and a more correct equation for activation energy is suggested. An abnormally low efficiency of neutral impurity scattering of charge carriers and strong optical absorption in the near-IR spectral range are demonstrated and attributed to upper conductive impurity band of negatively charged donors with an extra electron.

    The full text will be freely available from 2020-10-25 12:55
  • 9.
    Egilsson, T
    et al.
    Linkoping Univ, IFM, Dept Phys & Measurement Technol, S-58183 Linkoping, Sweden ABB Corp Res, S-72178 Vasteras, Sweden.
    Ivanov, Ivan Gueorguiev
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Henry, Anne
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Zeeman spectroscopy of the D-1 bound exciton in 3C-, and 4H-SiC1999In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 274, p. 677-680Article in journal (Refereed)
    Abstract [en]

    We have studied the D1 bound exciton (BE) in 3C-SiC (cubic) and 4H-SiC (hexagonal) by means of Zeeman spectroscopy. We show that the D-1-BE can be described by an electron-hole pair consisting of an (L-e = 0, S-e = 1/2) electron and a (L-h = 1, S-h = 1/2) hole, influenced by a number of interactions. In order to model the behaviour of the D-1-BE in magnetic field, an appropriate Hamiltonian equation is solved by using perturbation theory. The spin-orbit parameter and orbital g-value are small, indicating that the hole is tightly bound. (C) 1999 Elsevier Science B.V. All rights reserved.

  • 10.
    Engelbrecht, J A A
    et al.
    Nelson Mandela Metropolitan University.
    van Rooyen, I J
    Nelson Mandela Metropolitan University.
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Olivier, E J
    Nelson Mandela Metropolitan University.
    The origin of a peak in the reststrahlen region of SiC2012In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 407, no 10, p. 1525-1528Article in journal (Refereed)
    Abstract [en]

    A peak in the reststrahlen region of SiC is analyzed in order to establish the origin of this peak. The peak can be associated with a thin damaged layer on the SiC wafers, and a relation is found between surface roughness and the height of this peak, by modeling the damaged layer as an additional layer when simulating the reflectivity from the wafers.

  • 11.
    Engelbrecht, J.A. A.
    et al.
    Nelson Mandela Metropolitan University, South Africa .
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    van Rooyen, I.J.
    Idaho National Lab, ID 83415 USA .
    Impact of dielectric parameters on the reflectivity of 3C-SiC wafers with a rough surface morphology in the reststrahlen region2014In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 439, p. 115-118Article in journal (Refereed)
    Abstract [en]

    A layer-on-substrate model is used to obtain the infrared reflectance for 3C-SiC with a rough surface morphology. The effect of varying dielectric parameters of the "damaged layer" on the observed reflectivity of the 3C-SiC in the reststrahlen region is assessed. Different simulated reflectance spectra are obtained to those if the dielectric parameters of the "substrate" were varied. Most notable changes in the shape of the simulated reststrahlen peak are observed for changes in the high frequency dielectric constant, the phonon damping constant, the phonon frequencies and "thickness" of damaged surface layer.

  • 12.
    Eriksson, Jens
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Sensor Science. Linköping University, The Institute of Technology.
    Puglisi, Donatella
    Linköping University, Department of Physics, Chemistry and Biology, Applied Sensor Science. Linköping University, The Institute of Technology.
    Hsuan Kang, Yu
    Linköping University, Department of Physics, Chemistry and Biology, Applied Sensor Science. Linköping University, Faculty of Science & Engineering.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Lloyd Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Sensor Science. Linköping University, The Institute of Technology.
    Adjusting the electronic properties and gas reactivity of epitaxial graphene by thin surface metallization2014In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 439, p. 105-108Article in journal (Refereed)
    Abstract [en]

    Graphene-based chemical gas sensors normally show ultra-high sensitivity to certain gas molecules but at the same time suffer from poor selectivity and slow response and recovery Limes. Several approaches based on functionalization or modification of the graphene surface have been demonstrated as means to improve these issues, but most such measures result in poor reproducibility. In this study we investigate reproducible graphene surface modifications by sputter deposition of thin nanostructured Au or Pt layers. It is demonstrated that under the right metallization conditions the electronic properties of the surface remain those of graphene, while the surface chemistry is modified to improve sensitivity, selectivity and speed of response to nitrogen dioxide.

  • 13.
    Geller, Michael
    et al.
    University of Georgia, Athens, USA.
    Dennis, William
    University of Georgia, Athens, USA.
    Markel, Vadim
    Washington University, St. Louis, USA.
    Patton, Kelly
    University of Georgia, Athens, USA.
    Simon, Daniel
    University of California, Santa Cruz, USA.
    Yang, Ho-Soon
    Argonne National Laboratory, USA.
    Theory of electron–phonon dynamics in insulating nanoparticles2002In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 316-317, p. 430-433Article in journal (Refereed)
    Abstract [en]

    We discuss the rich vibrational dynamics of nanometer-scale semiconducting and insulating crystals as probed by localized electronic impurity states, with an emphasis on nanoparticles that are only weakly coupled to their environment. Two principal regimes of electron--phonon dynamics are distinguished, and a brief survey of vibrational-mode broadening mechanisms is presented. Recent work on the effects of mechanical interaction with the environment is discussed.

  • 14.
    Godlewski, M.
    et al.
    Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland.
    Goldys, E.M.
    Semiconductor Science and Technology Laboratory, Macquarie University, Sydney, NSW, Australia.
    Pozina, G.
    Department of Physics and Measurement Technology, Linkoping University, Linkoping, Sweden.
    Monemar, B.
    Department of Physics and Measurement Technology, Linkoping University, Linkoping, Sweden.
    Pakula, K.
    Institute of Experimental Physics, Warsaw University, Warsaw, Poland.
    Baranowski, J.M.
    Institute of Experimental Physics, Warsaw University, Warsaw, Poland.
    Prystawko, P.
    High Pressure Research Center (Unipress), Polish Academy of Sciences, Warsaw, Poland.
    Leszczynski, M.
    High Pressure Research Center (Unipress), Polish Academy of Sciences, Warsaw, Poland.
    In-plane and in-depth nonuniformities in defect distribution in GaN and InGaN epilayers2001In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 308-310, p. 102-105Article in journal (Refereed)
    Abstract [en]

    The in-plane and in-depth characteristics of the GaN and InGaN epilayers grown by the metalorganic chemical vapour deposition (MOCVD) on three different substrates (sapphire, SiC and bulk GaN) are evaluated. Relatively large intensity fluctuations of "edge" GaN and InGaN emissions are observed and are related to the details of the micro-structure of the GaN and InGaN films studied. The experiments indicate a nonuniform defect distribution in all types of the MOCVD films studied. In particular, the decoration of structural defects with impurities, an increased defect accumulation at the interfaces and a surprisingly small influence of the micro-structure on the in-plane homogeneity of the yellow band cathodoluminescence emission are observed. © 2001 Elsevier Science B.V. All rights reserved.

  • 15.
    Gogova, Daniela
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Talik, E.
    Institute of Physics, University of Silesia, Universytecka 4, 40007 Katowice, Poland.
    Ivanov, Ivan Gueorguiev
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Large-area free-standing GaN substrate grown by hydride vapor phase epitaxy on epitaxial lateral overgrown GaN template2006In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 371, no 1, p. 133-139Article in journal (Refereed)
    Abstract [en]

    In this paper, the potential of the high growth rate hydride vapor phase epitaxy technique and laser lift-off for the fabrication of large-area (2?) free-standing GaN substrates is revealed. Structural and optical properties of 250-µm-thick GaN layer grown on a MOVPE epitaxial lateral overgrown GaN template have been investigated employing different analytical experimental techniques. A low value of dislocation density of ~1×107 cm-2 on the Ga-terminated face of the free-standing material was determined from AFM images. X-ray diffraction (XRD), Raman scattering measurements, and low-temperature photoluminescence (PL) were exploited to assess the structural and optical quality of the GaN. The full-width at half-maximum value of XRD ?-scans of the free-standing GaN material was determined to be 264 arcsec for the (101¯4) reflection. The XRD and low-temperature PL mapping measurements consistently proved the good crystalline quality and lateral homogeneity and small residual stress inside the material. Hence, the free-standing GaN achieved is highly advantageous for a lattice-constant and thermal-expansion-coefficient matched substrate for additional strain-free homoepitaxy of III-nitrides-based device heterostructures. © 2005 Elsevier B.V. All rights reserved.

  • 16.
    Gällström, Andreas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Magnusson, Björn
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Beyer, Franziska
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Gali, Adam
    Budapest University of Technology and Economics, Hungary.
    Son Tien, Nguyen
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Leone, Stefano
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ivanov, Ivan Gueorguiev
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Hemmingsson, Carl
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Optical identification and electronic configuration of tungsten in 4H-and 6H-SiC2012In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 407, no 10, p. 1462-1466Article in journal (Refereed)
    Abstract [en]

    Several optically observed deep level defects in SiC are still unidentified and little is published on their behavior. One of the commonly observed deep level defects in semi-insulating SiC is UD-1. less thanbrgreater than less thanbrgreater thanThis report suggests that UD-1 is Tungsten related, based on a doping study and previously reported deep level transient spectroscopy data, as well as photo-induced absorption measurements. The electronic levels involved in the optical transitions of UD-1 are also deduced. The transitions observed in the photoluminescence of UD-1 are from a Gamma(C3v)(4), to two different final states, which transform according to Gamma(C3v)(5)circle plus Gamma(C3v)(6) and Gamma(C3v)(4), respectively.

  • 17.
    Henry, Anne
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Leone, Stefano
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Beyer, Franziska
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Pedersen, Henrik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Kordina, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Andersson, Sven
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    SiC epitaxy growth using chloride-based CVD2012In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 407, no 10, p. 1467-1471Article in journal (Refereed)
    Abstract [en]

    The growth of thick epitaxial SiC layers needed for high-voltage, high-power devices is investigated with the chloride-based chemical vapor deposition. High growth rates exceeding 100 mu m/h can be obtained, however to obtain device quality epilayers adjustments of the process parameters should be carried out appropriately for the chemistry used. Two different chemistry approaches are compared: addition of hydrogen chloride to the standard precursors or using methyltrichlorosilane, a molecule that contains silicon, carbon and chlorine. Optical and electrical techniques are used to characterize the layers.

  • 18.
    Hermansson, J.
    et al.
    Department of Physics, University of Lund, S-221 00 Lund, Sweden.
    Murin, L.I.
    Institute of Solid State and Semiconductor Physics, 220072 Minsk, Belarus, Institute of Solid State and Semiconductor Physics, National Academy of Sciences of Belarus, P. Brovki str. 17, 220072 Minsk, Belarus.
    Hallberg, T.
    Markevich, V.P.
    Institute of Solid State and Semiconductor Physics, 220072 Minsk, Belarus.
    Lindstrom, J.L.
    Lindström, J.L., Department of Physics, University of Lund, S-221 00 Lund, Sweden.
    Kleverman, M.
    Department of Physics, University of Lund, S-221 00 Lund, Sweden.
    Svensson, B.G.
    Royal Institute of Technology, S-16440, Kista-Stockholm, Sweden.
    Complexes of the self-interstitial with oxygen in irradiated silicon: A new assignment of the 936 cm-1 band2001In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 302-303, p. 188-192Conference paper (Other academic)
    Abstract [en]

    Three vibrational infrared absorption bands at about 936, 944 and 956 cm-1 appear commonly in spectra of Czochralski-grown silicon irradiated at low temperatures. All three bands have earlier been assigned to local vibrational modes related to oxygen in the complex of the silicon and the oxygen interstitials (IOi). However, it is shown that such an assignment of the 936 cm-1 band clearly is inconsistent with many facts and observations and that the band is most likely due to oxygen vibrations in the Si interstitial pair and interstitial oxygen complex, I2Oi. © 2001 Published by Elsevier Science B.V.

  • 19.
    Hoffmann, L
    et al.
    Aarhus Univ, Inst Phys & Astron, DK-8000 Aarhus C, Denmark RAS, Inst Radioengn & Elect, Moscow 103907, Russia Linkoping Univ, Dept Phys, S-58183 Linkoping, Sweden.
    Lavrov, EV
    Aarhus Univ, Inst Phys & Astron, DK-8000 Aarhus C, Denmark RAS, Inst Radioengn & Elect, Moscow 103907, Russia Linkoping Univ, Dept Phys, S-58183 Linkoping, Sweden.
    Nielsen, BB
    Aarhus Univ, Inst Phys & Astron, DK-8000 Aarhus C, Denmark RAS, Inst Radioengn & Elect, Moscow 103907, Russia Linkoping Univ, Dept Phys, S-58183 Linkoping, Sweden.
    Lindstrom, JL
    Local vibrational modes of a dicarbon-hydrogen center in crystalline silicon1999In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 274, p. 275-278Article in journal (Refereed)
    Abstract [en]

    Carbon-doped silicon irradiated with electrons at room temperature and subsequently implanted with protons has been studied by infrared absorption spectroscopy. Isochronal annealing in the temperature range from 400 degrees C to 800 degrees C has revealed an absorption line at 2967 cm(-1). When protons are substituted by deuterons, the line shifts down in frequency to 2211 cm(-1) and co-implantation of protons and deuterons gives rise to an additional line at 2218 cm(-1) Isotope shifts and similar annealing characteristics of the three lines show that the 2967 cm(-1) line represents a local vibrational mode of a defect, which contains two equivalent hydrogen atoms. In samples co-doped with C-12 and C-13, an additional mode is observed at 2963 cm(-1), which is about halfway between the modes involving only C-12 or C-13. From the relative intensities of the isotope-shifted modes in silicon co-doped with C-12 and C-13, it is concluded that the center contains two equivalent carbon atoms. The center is tentatively identified as two equivalent hydrogen atoms bound to two neighboring carbon atoms at substitutional sites. (C) 1999 Elsevier Science B.V. All rights reserved.

  • 20.
    Holtz, Per-Olof
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Hsu, Chih-Wei
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Larsson, L A
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Karlsson, K Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Dufåker, Daniel
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Lundskog, Anders
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Forsberg, Urban
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Moskalenko, Evgenii
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Dimastrodonato, V
    National University of Ireland University of Coll Cork.
    Mereni, L
    National University of Ireland University of Coll Cork.
    Pelucchi, E
    National University of Ireland University of Coll Cork.
    Optical characterization of individual quantum dots2012In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 407, no 10, p. 1472-1475Article in journal (Refereed)
    Abstract [en]

    Optical characterization of single quantum dots (QDs) by means of micro-photoluminescence (mu PL) will be reviewed. Both QDs formed in the Stranski-Krastanov mode as well as dots in the apex of pyramidal structures will be presented. For InGaAs/GaAs dots, several excitonic features with different charge states will be demonstrated. By varying the magnitude of an external electric or magnetic field and/or the temperature, it has been demonstrated that the transportation of carriers is affected and accordingly the charge state of a single QD can be tuned. In addition, we have shown that the charge state of the QD can be controlled also by pure optical means, i.e. by altering the photo excitation conditions. Based on the experience of the developed InAs/GaAs QD system, similar methods have been applied on the InGaN/GaN QD system. less thanbrgreater than less thanbrgreater thanThe coupling of LO phonons to the QD emission is experimentally examined for both charged and neutral excitons in single InGaAs/GaAs QDs in the apex of pyramidal structures. It is shown that the positively charged exciton exhibits a significantly weaker LO phonon coupling in the mu PL spectra than the neutral and negatively charged species, a fact, which is in consistency with model simulations performed.

  • 21.
    Högberg, Hans
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Tengdelius, Lina
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Samuelsson, Mattias
    Impact Coatings AB, Linkoping, Sweden .
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    beta-Ta and alpha-Cr thin films deposited by high power impulse magnetron sputtering and direct current magnetron sputtering in hydrogen containing plasmas2014In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 439, p. 3-8Article in journal (Refereed)
    Abstract [en]

    Thin films of beta-Ta and alpha-Cr were deposited on Si(1 0 0) and 1000 angstrom SiO2/Si(1 0 0), by high power impulse magnetron sputtering (HiPIMS) and direct current magnetron sputtering (dcMS) in hydrogen-containing plasmas. The films were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction, scanning electron microscopy, elastic recoil detection analysis, and four-point probe measurements. The results showed that 001-oriented beta-Ta films containing up to similar to 8 at% hydrogen were obtained with HiPIMS, albeit with no chemical shift evident in XPS. The 110 oriented alpha-Cr films display a hydrogen content less than the detection limit of 1 at%, but H-2 favors the growth of high-purity films for both metals. The beta-Ta films deposited with dcMS are columnar, which seems independent of H-2 presence in the plasma, while the films grown by HIPIMS are more fine-grained. The latter type of microstructure was present for the alpha-Cr films and found to be independent on choice of technique or hydrogen in the plasma. The beta-Ta films show a resistivity of similar to 140-180 mu Omega cm, while alpha-Cr films exhibit values around 30 mu Omega cm; the lowest values obtained for films deposited by HiPIMS and with hydrogen in the plasma for both metals.

  • 22.
    Iwata, HP
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Lindefelt, Ulf
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Öberg, S
    Department of Mathematics, Luleå University of Technology, Luleå, Sweden.
    Briddon, PR
    Department of Physics, University of Newcastle upon Tyne, Newcastle, UK.
    Stacking faults in silicon carbide2003In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 340, p. 165-170Article in journal (Refereed)
    Abstract [en]

    We review of our theoretical work on various stacking faults in SiC polytypes. Since the discovery of the electronic degradation phenomenon in 4H-SiC p-i-n diodes, stacking faults in SiC have become a subject of intensive study around the globe. At the beginning of our research project, the aim was to find the culprit for the degradation phenomenon, but in the course of this work we uncovered a wealth of information for the general properties of stacking faults in SiC. An intuitive perspective to the diverse nature of stacking faults in SiC will be given in this conference report. (C) 2003 Published by Elsevier B.V.

  • 23.
    Janzén, Erik
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Gali, Adam
    Budapest University Technology and Econ, Department Atom Phys, H-1111 Budapest, Hungary .
    Carlsson, Patrick
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Gällström, Andreas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Magnusson, Björn
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Son, Nguyen Tien
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    The silicon vacancy in SiC2009In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 404, no 22, p. 4354-4358Article in journal (Refereed)
    Abstract [en]

    The isolated silicon vacancy is one of the basic intrinsic defects in SiC. We present new experimental data as well as new calculations on the silicon vacancy defect levels and a new model that explains the optical transitions and the magnetic resonance signals observed as occurring in the singly negative charge state of the silicon vacancy in 4H and 6H SiC.

  • 24.
    Kaputkina, N.E.
    et al.
    Moscow Institute for Steel.
    Lozovik, Yu.E.
    Academy of Sciences of Russia.
    Willander, Magnus
    Göteborg University.
    Influence of the magentic field on formation and spectrum of the exciton-polariton in a microcavity2006In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 378-380, p. 1049-1050Article in journal (Refereed)
    Abstract [en]

    Magnetic field effect on properties of exciton–polaritons in an optical microcavity and on direct and indirect excitons in single and coupled quantum wells is considered. Magnetic field controls exciton dispersion curve and its intersection with microcavity photon dispersion curve. This gives the possibility to control exciton–polariton formation, polariton splitting and polariton dispersion. Excitons and exciton–polaritons on higher Landau levels are discussed.

  • 25.
    Karlsson, K. Fredrik
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Supaluck, Amloy
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Chen, Y. T.
    Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan.
    Chen, K. H.
    Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan.
    Hsu, H. C.
    National Taiwan University, Taipe.
    Hsiao, C. L.
    National Taiwan University, Taipe.
    Chen, L. C.
    National Taiwan University, Taipe.
    Holtz, Per-Olof
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Polarized emission and excitonic fine structure energies of InGaN quantum dots2012In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 407, no 10, p. 1553-1555Article in journal (Refereed)
    Abstract [en]

    The linear polarization of the excitonic emission from quantum dot-like potential minima formed in a thin InGaN layer is investigated. The recorded emission lines exhibit significant intensity linearly polarized along the wurtize c-axis. For many of the studied spectra, the excitonic fine-structures were resolved, revealing energy splittings in the order of ∼200 μeV.

  • 26.
    Kemerink, Martijn
    et al.
    Eindhoven University of Technology, Netherlands.
    Koenraad, PM
    Eindhoven University of Technology, Netherlands.
    Wolter, JH
    Eindhoven University of Technology, Netherlands.
    Exchange interaction in degenerate p-type quantum wells1998In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 256, p. 503-506Article in journal (Refereed)
    Abstract [en]

    A detailed comparison between a magneto-transport experiment on a p-type GaAs/AlGaAs quantum well and model calculations is presented. It is shown that for all magnetic fields the Shubnikov-de Haas (SdH) trace is strongly influenced by the exchange interaction, in contrast with n-type structures where this interaction is only important in high magnetic fields. As a consequence, the effective hole masses that are extracted from the temperature dependence of the SdH oscillations are not a good measure of the single-particle hole mass, and can be regarded as meaningless. (C) 1998 Elsevier Science B.V. All rights reserved.

  • 27.
    Khranovskyy, Volodymyr
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Eriksson, Martin O.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Radnóczi, György Zoltán
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Khalid, Abbas
    University of Dublin Trinity Coll, Ireland.
    Zhang, Hongzhou
    University of Dublin Trinity Coll, Ireland.
    Holtz, Per-Olof
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Correction: Photoluminescence study of basal plane stacking faults in ZnO nanowires (vol 4639, pg 50, 2014)2014In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 454, p. 279-279Article in journal (Other academic)
    Abstract [en]

    n/a

  • 28.
    Khranovskyy, Volodymyr
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Eriksson, M.O.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Zoltán Radnóczi, György
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Khalid, A.
    University of Dublin Trinity Coll, Ireland University of Dublin Trinity Coll, Ireland .
    Zhang, H.
    University of Dublin Trinity Coll, Ireland University of Dublin Trinity Coll, Ireland .
    Holtz, Per-Olof
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Photoluminescence study of basal plane stacking faults in ZnO nanowires2014In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 439, p. 50-53Article in journal (Refereed)
    Abstract [en]

    We have investigated the photoluminescence (PL) of ZnO nanowires (NWs) containing a high density (similar to 1 x 10(6) cm(-1)) of basal plane stacking faults (BSFs). It was observed that the BSFs result in a specific PL peak at similar to 3.329 eV along with a donor bound excitonic emission (D degrees X) peak at 5 K. The observed BSF-related emission is of excitonic type and possesses longer PL lifetime than D degrees X (similar to 360 ps vs. similar to 70 ps). Via comparison of the microstructural and the PL properties of the ZnO NWs, it is shown that the observed BSF-related emission is due to the formation of crystal phase quantum wells (QWs). This is explained by the fact that BSF in wurtzite (WZ) ZnO is the thinnest segment of zinc blende (ZB) phase ZnO inserted in the WZ matrix, resulting in band alignment of type II due to the conduction and valence band offsets of ZB with respect to WZ ZnO. The mechanism of the BSF related PL is suggested to be an indirect exciton transitions clue to the recombination of electrons confined in the ZB QWs to holes in the WZ barriers localized near the BSFs.

  • 29.
    Khranovskyy, Volodymyr
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Morphology engineering of ZnO nanostructures2012In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 407, no 10, p. 1533-1537Article in journal (Refereed)
    Abstract [en]

    Nanosized ZnO structures were grown by atmospheric pressure metalorganic chemical vapor deposition (APMOCVD) in the temperature range 200-500 degrees C at variable precursor pressure. Temperature induced evolution of the ZnO microstructure was observed, resulting in regular transformation of the material from conventional polycrystalline layers to hierarchically arranged sheaves of ZnO nanowires. The structures obtained were uniformly planarly located over the substrate and possessed as low nanowires diameter as 30-45 nm at the tips. The observed growth evolution is explained in terms of ZnO crystal planes free energy difference and growth kinetics. For comparison, the convenient growth at constant precursor pressure on Si and SiC substrates has been performed, resulting in island-type grown ZnO nanostructures. The demonstrated nanosized ZnO structures may have unique possible areas of application, which are listed here.

  • 30.
    Khranovskyy, Volodymyr
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Karlsson, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Syed, Abdul S
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Holtz, Per-Olof
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Nigussa Urgessa, Zelalem
    Nelson Mandela Metropolitan University, South Africa.
    Oluwafemi, Oluwatobi Samuel
    Walter Sisulu University, South Africa.
    Reinhardt Botha, Johannes
    Nelson Mandela Metropolitan University, South Africa.
    Comparative PL study of individual ZnO nanorods, grown by APMOCVD and CBD techniques2012In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 407, no 10, p. 1538-1542Article in journal (Refereed)
    Abstract [en]

    The photoluminescence properties of individual ZnO nanorods, grown by atmospheric pressure metalorganic chemical vapor deposition (APMOCV) and chemical bath deposition (CBD) are investigated by means of temperature dependent micro-PL. It was found that the low temperature PL spectra are driven by neutral donor bound exciton emission (DX)-X-0, peaked at 3.359 and 3.363 eV for APMOCVD and CBD ZnO nanorods, respectively. The temperature increase causes a red energy shift of the peaks and enhancement of the free excitonic emission (FX). The FX was found to dominate after 150 K for both samples. It was observed that while APMOCVD ZnO nanorods possess a constant low signal of visible deep level emission with temperature, the ZnO nanorods grown by CBD revealed the thermal activation of deep level emission (DLE) after 130 K. The resulting room temperature DLE was a wide band located at 420-550 nm. The PL properties of individual ZnO nanorods can be of importance for their forthcoming application in future optoelectronics and photonics.

  • 31.
    Lavrov, EV
    et al.
    Aarhus Univ, Inst Phys & Astron, DK-8000 Aarhus, Denmark RAS, Inst Radioengn & Elect, Moscow 103907, Russia Aarhus Univ, Inst Chem, DK-8000 Aarhus, Denmark Linkoping Univ, S-58183 Linkoping, Sweden.
    Nielsen, BB
    Aarhus Univ, Inst Phys & Astron, DK-8000 Aarhus, Denmark RAS, Inst Radioengn & Elect, Moscow 103907, Russia Aarhus Univ, Inst Chem, DK-8000 Aarhus, Denmark Linkoping Univ, S-58183 Linkoping, Sweden.
    Byberg, J
    Aarhus Univ, Inst Phys & Astron, DK-8000 Aarhus, Denmark RAS, Inst Radioengn & Elect, Moscow 103907, Russia Aarhus Univ, Inst Chem, DK-8000 Aarhus, Denmark Linkoping Univ, S-58183 Linkoping, Sweden.
    Lindstrom, JL
    Infrared absorption study of a new dicarbon center in silicon1999In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 274, p. 256-259Article in journal (Refereed)
    Abstract [en]

    Infrared absorption measurements on n-type silicon doped with carbon and irradiated with electrons at room temperature have revealed new absorption lines at 527.4 and 748.7 cm(-1). The 748.7 cm(-1) line is observed only when the sample is cooled down in the dark and the spectra are measured through a low-pass filter with cut-off frequency below 6000 cm(-1). Light of frequency above 6000 cm(-1) removes this line and generates the 527.4-cm(-1) line. Spectra recorded on silicon doped with C-13 show that the two lines represent local vibrational modes of a carbon defect. The annealing behavior of the 748.7-cm(-1) line and of the EPR signal of two neighboring substitutional carbon atoms, (C-s-C-s)(-), are identical. The 527.4- and 748.7-cm(-1) modes are identified as the modes of C-s-C-s in neutral and negative charge states, respectively. The formation of C-s-C-s is investigated, and it is shown that the center may arise when a vacancy is trapped by the metastable substitutional carbon-interstitial carbon center, C-s-C-i. (C) 1999 Elsevier Science B.V. All rights reserved.

  • 32.
    Lindstrom, J.L.
    et al.
    Lindström, J.L., Department of Physics - Solid State Physics, University of Lund, PO Box 118, SE-221 00 Lund, Sweden.
    Hallberg, T.
    Defence Research Establishment, PO Box 1165, SE-581 11, Linkoping, Sweden.
    Hermansson, J.
    Department of Physics - Solid State Physics, University of Lund, PO Box 118, SE-221 00 Lund, Sweden.
    Murin, L.I.
    Institute of Solid State and Semiconductor Physics, 220072 Minsk, Belarus.
    Komarov, B.A.
    Institute of Solid State and Semiconductor Physics, 220072 Minsk, Belarus.
    Markevich, V.P.
    Institute of Solid State and Semiconductor Physics, 220072 Minsk, Belarus, Centre for Electronic Materials, UMIST, Manchester M60 1QP, United Kingdom.
    Kleverman, M.
    Department of Physics - Solid State Physics, University of Lund, PO Box 118, SE-221 00 Lund, Sweden.
    Svensson, B.G.
    Solid State Electronics, Royal Institute of Technology, SE-164 40 Kista, Sweden.
    Interaction between self-interstitials and the oxygen dimer in silicon2001In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 308-310, p. 284-289Article in journal (Refereed)
    Abstract [en]

    Interactions between the oxygen dimer (O2i) and silicon self-interstitials (I) and vacancies (V) have been studied in Czochralski-grown silicon (Cz-Si) crystals using infrared absorption and deep level transient spectroscopies. The focus in this report is on reactions of O2i with I. The first step in this interaction is found to be the formation of a self-interstitial-dioxygen centre (IO2i) with oxygen-related local vibrational mode (LVM) bands at 922 and 1037 cm-1. During the second formation step, another centre, I2O2i, with LVM bands at 918 and 1034 cm-1 is suggested to appear. A Si-related band at about 545 cm-1 is also assigned to both the IO2i and I2O2i centres. The IO2i centre is found to be electrically active with an acceptor level at Ec - 0.11 eV. The both defects, IO2i and I2O2i, are stable at room temperature and anneal out at about 400 and 550 K, respectively. © 2001 Elsevier Science B.V. All rights reserved.

  • 33. Lindstrom, JL
    et al.
    Murin, LI
    Univ Lund, Dept Phys Solid State Phys, S-22100 Lund, Sweden Inst Solid State & Semicond Phys, Minsk 220072, Byelarus Natl Def Res Estab, S-58111 Linkoping, Sweden Royal Inst Technol, S-16440 Kista, Sweden.
    Markevich, VP
    Univ Lund, Dept Phys Solid State Phys, S-22100 Lund, Sweden Inst Solid State & Semicond Phys, Minsk 220072, Byelarus Natl Def Res Estab, S-58111 Linkoping, Sweden Royal Inst Technol, S-16440 Kista, Sweden.
    Hallberg, T
    Univ Lund, Dept Phys Solid State Phys, S-22100 Lund, Sweden Inst Solid State & Semicond Phys, Minsk 220072, Byelarus Natl Def Res Estab, S-58111 Linkoping, Sweden Royal Inst Technol, S-16440 Kista, Sweden.
    Svensson, BG
    Vibrational absorption from vacancy-oxygen-related complexes (VO, V2O, VO2) in irradiated silicon1999In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 274, p. 291-295Article in journal (Refereed)
    Abstract [en]

    Infrared absorption from oxygen-related defects in Si crystals irradiated with electrons (2.5 MeV) at room temperature (RT) and in the range 300-600 degrees C has been investigated. Two new vibrational bands positioned at 10 K at about 1370 and 1430 cm(-1) were observed in samples irradiated at RT. A good correlation is found between these lines and the bands at 836 and 885 cm(-1) known to originate from asymmetrical stretching vibrations (B-1 mode) of an oxygen atom in the neutral and negative VO complex. An attribution of the 1370 and 1430 cm(-1) bands to a combination of the B-1 mode with the symmetrical stretching A(1) mode (weakly IR active) for different charge states of VO is argued to be the most probable. A band at 833.4 cm(-1) is found to increase in strength upon annihilation of divacancies at 250-300 degrees C. The V2O complex is suggested to give rise to this band. New experimental data confirming an attribution of the 895 cm(-1) band to the VO2 complex are presented as well. (C) 1999 Elsevier Science B.V. All rights reserved.

  • 34.
    Lindstrom, J.L.
    et al.
    Lindström, J.L., Department of Physics, Solid State Physics, University of Lund, P.O. Box 118, SE-221 00 Lund, Sweden.
    Murin, L.I.
    Inst. Solid Stt./Semiconduct. Phys., 220072 Minsk, Belarus.
    Svensson, B.G.
    Department of Physics, Oslo University, N-0316 Oslo, Norway.
    Markevich, V.P.
    Centre for Electronic Materials, UMIST, Manchester M60 1QD, United Kingdom.
    Hallberg, T.
    The VO2* defect in silicon2003In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 340-342, p. 509-513Conference paper (Other academic)
    Abstract [en]

    The vacancy-dioxygen complex (VO2) is one of the main defects formed in irradiated Cz-Si crystals upon annealing (or irradiation) in the temperature range 300-400°C. In this defect two oxygen atoms share a vacancy, each bonded to two silicon neighbors. Independent vibrations of these O atoms give rise to one infrared absorption band at 895.5 cm-1 at 10 K. We report on an experimentally discovered bistability of this defect. We suggest an alternative configuration, VO2*, where only one O atom is inside the vacancy while the second O atom is in a backbond position. Two vibrational bands, at 928.4 and 1003.8 cm-1 (positions at 15 K), are assigned to this configuration. © 2003 Elsevier B.V. All rights reserved.

  • 35.
    Monemar, Bo
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Paskov, Plamen
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Bergman, Peder
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Iwaya, M
    Kamiyama, S
    Amano, H
    Akasaki, I
    A hydrogen-related shallow donor in GaN?2006In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 376, p. 460-463Article in journal (Refereed)
    Abstract [en]

    We present photoluminescence (PL) data for deliberately O-doped, high-resistive GaN samples where a new shallow donor-bound exciton (DBE) peak at about 3.4746 eV (corrected for strain shift) at 2 K appears. This DBE is strongly enhanced upon annealing in the entire range 450-900 degrees C. The possible relation of this DBE to a metastable H donor state is discussed. (c) 2006 Elsevier B.V. All rights reserved.

  • 36.
    Monemar, Bo
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Paskov, Plamen
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Bergman, Peder
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Paskova, Tanja
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Hemmingsson, Carl
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Malinauskas, T
    Jarasiunas, K
    Gibart, P
    Beaumont, B
    Time-resolved spectroscopy of excitons bound at shallow neutral donors in HVPE GaN2006In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 376, p. 482-485Article in journal (Refereed)
    Abstract [en]

    Time-resolved photo luminescence (TRPL) data for temperatures 2-150 K are presented for two thick HVPE samples grown in two different laboratories. The samples both have residual O and Si shallow donor concentrations in the 10(16)cm(-3) range. The radiative decay time for neutral donor-bound excitons (DBEs) related to these donors is found to be about 300 ps. The decay of the DBEs at longer decay times is found to be related to feeding from the free exciton-polariton states. At elevated temperatures the decay of the DBE is very similar to the free exciton decay. (c) 2006 Elsevier B.V. All rights reserved.

  • 37.
    Murin, L.I.
    et al.
    Institute of Solid State and Semiconductor Physics, P. Brovki Street 17, Minsk 220072, Belarus.
    Lindstrom, J.L.
    Lindström, J.L., Department of Physics, Lund University, S-221 00 Lund, Sweden.
    Markevich, V.P.
    Centre for Electronic Materials, UMIST, M60 1QD Manchester, United Kingdom.
    Hallberg, T.
    Litvinov, V.V.
    Belarusian State University, F. Scorina av. 4, 220050 Minsk, Belarus.
    Coutinho, J.
    School of Physics, University of Exeter, EX4 4QL Exeter, United Kingdom.
    Jones, R.
    School of Physics, University of Exeter, EX4 4QL Exeter, United Kingdom.
    Briddon, P.R.
    Department of Physics, University of Newcastle, NE1 7RU Newcastle, United Kingdom.
    Oberg, S.
    Öberg, S., Department of Mathematics, Luleå University of Technology, S-97187 Luleå, Sweden.
    Isotopic effects on vibrational modes of thermal double donors in Si and Ge2001In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 308-310, p. 290-293Article in journal (Refereed)
    Abstract [en]

    The local vibrational modes of thermal double donors in Si and Ge are investigated by FTIR and ab initio modelling. At most, two oxygen modes are detected from each donor, which exhibit regular shifts with increasing donor number. By using mixtures of 16O and 18O, it is found that in Si the upper band does not yield any new modes suggesting that any oxygen atom is decoupled from any other. However, the lower frequency bands exhibit unique mixed modes proving for the first time that oxygen atoms are coupled together and in close spatial proximity. Ab initio calculations demonstrate that the modes and their isotopic shifts are consistent with a model involving two parallel chains of oxygen atoms linking second neighbour Si atoms, terminated by O-atoms close to the normal position for interstitial O. © 2001 Elsevier Science B.V. All rights reserved.

  • 38.
    Murin, L.I.
    et al.
    Institute of Solid State and Semiconductor Physics, P. Brovki Street 17, 220072 Minsk, Belarus.
    Markevich, V.P.
    Institute of Solid State and Semiconductor Physics, P. Brovki Street 17, 220072 Minsk, Belarus.
    Suezawa, M.
    Institute for Materials Research, Tohoku University, Sendai 980-77, Japan.
    Lindstrom, J.L.
    Lindström, J.L., Department of Physics, University of Lund, S-221 00 Lund, Sweden.
    Kleverman, M.
    Department of Physics, University of Lund, S-221 00 Lund, Sweden.
    Hallberg, T.
    Early stages of oxygen clustering in hydrogenated Cz-Si: IR absorption studies2001In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 302-303, p. 180-187Conference paper (Other academic)
    Abstract [en]

    The formation kinetics of small oxygen clusters in hydrogenated Si has been studied by means of infrared absorption measurements. Hydrogen was introduced into the crystals by in-diffusion from H2 gas at 1200-1300°C. The samples were heated at temperatures in the range of 280-370°C for different durations. At initial stages of heat-treatment, enormous generation rates of the oxygen dimer have been observed in hydrogenated samples. This indicates highly enhanced diffusion of the interstitial oxygen atoms. The maximum achievable concentration of the dimers is found to be limited by their dissociation rate even at temperatures of about 300°C, while in as-grown crystals the capture processes are known to be dominant in this temperature region. An explanation of this phenomenon is presented. © 2001 Published by Elsevier Science B.V.

  • 39.
    Narayan, V.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Rorison, J.M.
    Sharp Laboratories of Europe Ltd, Oxford Science Park, Oxford OX4 4GA, Oxford, United Kingdom.
    Inkson, J.C.
    School of Physics, University of Exeter, Stocker Road, Exeter EX4 4 QL, United Kingdom.
    Calculation of the temperature dependence of hot electron scattering in heavily p-doped GaAs using a high-temperature approximation to the dielectric function2002In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 324, no 1-4, p. 393-402Article in journal (Refereed)
    Abstract [en]

    Using a high-temperature approximation to the dielectric function within the random phase approximation, we calculate hot electron scattering rates, as a function of temperature and doping density, in p-doped GaAs. The dielectric function of the holes contains contributions from intraband excitations and interband excitations. The former reduces to an analytic form within the two pole approximation (which used Boltzmann statistics), whereas the latter was calculated numerically. The collective excitation mode of the holes was defined by intraband excitations, since at very small wavevectors, the interband excitations vanish. However, at low temperature the interband excitations were found to be the dominant Landau damping mechanism, which strongly suppressed the plasmon at moderate doping levels. At high temperature the excitations from the heavy to light band were partially suppressed, and the plasmon was not overwhelmingly Landau damped by either interband or intraband excitations. At room temperature, an analytic dielectric function where the interband excitations have been neglected, may be used to accurately calculate hot electron mean free paths. This approximation was found to become more accurate with lower doping levels, but was not appropriate at low temperature. © 2002 Elsevier Science B.V. All rights reserved.

  • 40.
    Nguyen, Son Tien
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Hai, P. N.
    Huy, P. T.
    Gregorkiewicz, T.
    Ammerlaan, C. A. J.
    Lindström, J. L.
    Chen, Weimin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Electron-paramagnetic-resonance studies of defects in electron-irradiated p-type 4H and 6H SiC1999In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 273-274, p. 655-658Article in journal (Refereed)
    Abstract [en]

     Defects in p-type 4H and 6H SiC irradiated by 2.5 MeV electrons were studied by electron paramagnetic resonance (EPR). Two anisotropic EPR spectra, labeled I and II, were observed in both 4H and 6H SiC. These spectra demonstrating triclinic symmetry of the center can be described by an effective electron spin S=1/2. The angle α between the direction of the principal gz of the g-tensors and the c-axis is determined as 63° and 50° for spectra I and II, respectively. In the 6H polytype, a third also similar EPR spectrum was detected. Based on their similarity in the electronic structure (electron spin, symmetry, g values), annealing behavior and temperature dependence, these spectra are suggested to be related to the same defect occupying different inequivalent lattice sites in 4H and 6H SiC. A pair between a silicon vacancy and an interstitial is a possible model for the defect.

  • 41.
    Nguyen, Son Tien
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ivanov, Ivan Gueorguiev
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Kuznetsov, A. Yu.
    Department of Physics, Center for Materials Science and Technology, University of Oslo, Oslo, Norway.
    Svensson, B.G.
    Department of Physics, Center for Materials Science and Technology, University of Oslo, Oslo, Norway.
    Zhao, Qing Xiang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Morishita, M.N.
    Japan Atomic Energy Agency, Takasaki, Gunma, Japan.
    Ohshima, T.
    Japan Atomic Energy Agency, Takasaki, Gunma, Japan.
    Itoh, H.
    Japan Atomic Energy Agency, Takasaki, Gunma, Japan.
    Isoya, J.
    University of Tsukuba, Tsukuba, Japan.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Magnetic resonance studies of defects in electron-irradiated ZnO substrates2007In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 401-402, p. 507-510Article in journal (Refereed)
    Abstract [en]

    Optical detection of magnetic resonance (ODMR) was used to study defects in electron-irradiated ZnO substrates. In addition to the shallow donor and the Zn vacancy, several ODMR centers with an effective electron spin were detected. Among these, the axial LU3 and non-axial LU4 centers are shown to be dominating recombination centers. The annealing behavior of radiation-induced defects was studied and possible defect models are discussed.

  • 42.
    Nilsson, H.-E.
    et al.
    Department of Information Technology and Media, Mid-Sweden University, S-85170 Sundsvall, Sweden.
    Martinez, A.
    Royal Institute of Technology, KTH, Electrum 229, S-16440 Kista, Sweden.
    Sannemo, Ulf
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Hjelm, M.
    Department of Information Technology and Media, Mid-Sweden University, S-85170 Sundsvall, Sweden, Royal Institute of Technology, KTH, Electrum 229, S-16440 Kista, Sweden.
    Bellotti, E.
    Department of Electrical and Computer Engineering, Boston University, 8 St. Mary's Street, Boston, MA 02215, United States.
    Brennan, K.
    School of Electrical and Computer Engineering, Georgia Tech, Atlanta, GA 30332-0250, United States.
    Monte Carlo simulation of high field hole transport in 4H-SiC including band to band tunneling and optical interband transitions2002In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 314, no 1-4, p. 68-71Conference paper (Other academic)
    Abstract [en]

    The high field hole transport in 4H-SiC has been studied using a full band Monte Carlo (MC) simulation model that includes band to band tunneling and allows mixing of the band states during carrier drift. Impact ionization coefficients along the c-axis direction have been extracted and compared with experimental data. It is shown that the band to band tunneling mechanism is crucial in order to explain experimental results. The carrier distribution function obtained from the MC simulations has been used to determine the breakdown luminescence spectra coming from interband transitions. Our results are in good agreement with the available experimental luminescence spectra for SiC polytypes, and the importance of including interband tunneling is clearly demonstrated. © 2002 Elsevier Science B.V. All rights reserved.

  • 43.
    Nur, Omer
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Israr, Muhammad Q.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    El Desouky, Fawzy G.
    NRC, Egypt .
    Salem, Mohamed A.
    NRC, Egypt .
    Abou Hamad, Ali B.
    NRC, Egypt .
    Battisha, Inas K.
    NRC, Egypt .
    Effect of elevated concentrations of strontium and iron on the structural and dielectric characteristics of Ba(1-x-y)Sr(x)Ti Fe(y)O3 prepared through sol-gel technique2012In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 407, no 14, p. 2697-2704Article in journal (Refereed)
    Abstract [en]

    Nano-composite Ba1-xSr(x)TiO3 (BST), where x=0.01-0.50 and doped with different concentrations of iron Ba(1-x-y)Sr(x)TiFe(y)O3 (BSTF), where x=0.01 and y=0.01-0.05 powders were prepared by sol-gel method. The effect of increasing the iron and strontium concentrations substituted in Barium strontium titanate system will be studied. The prepared samples have a tetragonal crystalline phase after sintering for 1 h at 750 degrees C in air. The structural and the morphological features of the systems have been studied using X-ray diffraction (XRD), transmission electron microscope (TEM) and scanning electron microscope (SEM). The dielectric properties of the BST and BSTF systems have been investigated as a function of temperature and frequency. The dielectric measurements are carried out in the frequency range 42 Hz-1 MHz, at a temperature ranging between 25 and 250 degrees C. The results showed a decrease in T-c temperature giving the following values 90 and 85 degrees C for B10ST and B10ST5F prepared powder samples, respectively, implying tetragonal, feroelectric phase at lower temperature into cubic, para-electric phase at temperature higher than T-c.

  • 44.
    Paskov, Plamen
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Schifano, R
    Paskova, Tanja
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Malinauskas, T
    Bergman, Peder
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Figge, S
    Hommel, D
    Structural defect-related emissions in nonpolar a-plane GaN2006In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 376, p. 473-476Article in journal (Refereed)
    Abstract [en]

    We have studied the optical emission properties of a-plane GaN layers grown on r-plane sapphire by metalorganic chemical vapor deposition. Together with the typical band edge exciton emission, the photoluminescence (PL) spectra reveal three low-energy emissions peaked at 3.42, 3.34 and 3.29eV. which are related to structural defects. Temperature and excitation dependent stationary PL and the time-resolved PL have been employed in order to understand the exact origin of these emissions. The 3.42 and 3.34eV emissions are found to be of an intrinsic origin and are associated with carriers localized at stacking faults. The emission at 3.29eV shows a donor-acceptor pair behavior suggesting that impurities attached to structural defects most likely partial dislocations terminating stacking faults are involved. (c) 2005 Elsevier B.V. All rights reserved.

  • 45.
    Stenberg, Pontus
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Booker, Ian Don
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Karhu, Robin
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Pedersen, Henrik
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Ivanov, Ivan Gueorguiev
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Defects in silicon carbide grown by fluorinated chemical vapor deposition chemistry2018In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 535, p. 44-49Article in journal (Refereed)
    Abstract [en]

    Point defects in n- and p-type 4H-SiC grown by fluorinated chemical vapor deposition (CVD) have been characterized optically by photoluminescence (PL) and electrically by deep-level transient spectroscopy (DLTS) and minority carrier transient spectroscopy (MCTS). The results are considered in comparison with defects observed in non-fluorinated CVD growth (e.g., using SiH4 instead of SiF4 as silicon precursor), in order to investigate whether specific fluorine-related defects form during the fluorinated CVD growth, which might prohibit the use of fluorinated chemistry for device-manufacturing purposes. Several new peaks identifying new defects appear in the PL of fluorinated-grown samples, which are not commonly observed neither in other halogenated chemistries, nor in the standard CVD chemistry using silane (SiH4). However, further investigation is needed in order to determine their origin and whether they are related to incorporation of F in the SiC lattice, or not. The electric characterization does not find any new electrically-active defects that can be related to F incorporation. Thus, we find no point defects prohibiting the use of fluorinated chemistry for device-making purposes.

  • 46.
    Vorona, Igor
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Mchedlidze, T
    Izadifard, Morteza
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Buyanova, Irina A
    Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials. Linköping University, The Institute of Technology.
    Chen, Weimin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Hong, YG
    Tu, CW
    Signatures of grown-in defects in GaInNP alloys grown on a GaAs substrate from magnetic resonance studies2006In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 376, p. 571-574Article in journal (Refereed)
    Abstract [en]

    Three grown-in defects acting as centers of non-radiative recombination (NR) were detected in GaInNP alloys grown on a GaAs substrate using the optically detected magnetic resonance (ODMR) technique. Among them, one was proposed to be either a Ga-i-related defect or an AS(Ga)-related defect, from the resolved four-line hyperfine structure. The former model was concluded to be more favorable by weighing physical properties of the two defects, e.g. the likelihood for their presence in the studied structures, their spatial location, g-value and effect of rapid thermal annealing (RTA). RTA at 700 degrees C was shown to reduce concentrations of the studied defects but it introduced a new defect that likely directly participates in the monitored radiative recombination process in the RTA-treated samples. (c) 2005 Elsevier B.V. All rights reserved.

  • 47.
    Wang, Xiangjun
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics .
    Buyanova, Irina A.
    Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials. Linköping University, The Institute of Technology.
    Chen, Weimin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Pan, C.J.
    Department of Electrical and Computer Engineering, University of California, La Jolla, United States, Optical Sciences Center, National Central University, Jhongli, Taoyuan 32001, Taiwan.
    Tu, C.W.
    Department of Electrical and Computer Engineering, University of California, La Jolla, United States.
    Optical characterization studies of grown-in defects in ZnO epilayers grown by molecular beam epitaxy2007In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 401-402, p. 413-416Article in journal (Refereed)
    Abstract [en]

    Defect formation in ZnO epilayers grown by molecular beam epitaxy (MBE) is studied by employing optical characterization techniques such as photoluminescence (PL) and optically detected magnetic resonance (ODMR). Excess of oxygen during the growth was found to cause an appearance of the PL peak at around 3.338 eV, which indicates that the corresponding defects are predominantly formed in O-rich ZnO. On the other hand, non-stoichiometry during the growth was singled out as the main factor facilitating formation of defects involved in the yellow PL emission band peaking at around 2.17 eV. Several magnetic-resonance active defects are revealed via monitoring this emission and their magnetic-resonance signatures are obtained. © 2007 Elsevier B.V. All rights reserved.

  • 48.
    Yakimova, Rositsa
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Iakimov, Tihomir
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Yazdi, Gholamreza
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Bouhafs, Chamseddine
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Eriksson, J.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Zakharov, A.
    MaxLab, Sweden .
    Boosalis, A.
    University of Nebraska, NE 68588 USA University of Nebraska, NE 68588 USA .
    Schubert, M.
    University of Nebraska, NE 68588 USA University of Nebraska, NE 68588 USA .
    Darakchieva, Vanya
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Morphological and electronic properties of epitaxial graphene on SiC2014In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 439, p. 54-59Article in journal (Refereed)
    Abstract [en]

    We report on the structural and electronic properties of graphene grown on SiC by high-temperature sublimation. We have studied thickness uniformity of graphene grown on 4H-SiC (0 0 0 1), 6H-SiC (0 0 0 1), and 3C-SiC (1 1 1) substrates and investigated in detail graphene surface morphology and electronic properties. Differences in the thickness uniformity of the graphene layers on different SiC polytypes is related mainly to the minimization of the terrace surface energy during the step bunching process. It is also shown that a lower substrate surface roughness results in more uniform step bunching and consequently better quality of the grown graphene. We have compared the three SiC polytypes with a clear conclusion in favor of 3C-SiC. Localized lateral variations in the Fermi energy of graphene are mapped by scanning Kelvin probe microscopy It is found that the overall single-layer graphene coverage depends strongly on the surface terrace width, where a more homogeneous coverage is favored by wider terraces, It is observed that the step distance is a dominating, factor in determining the unintentional doping of graphene from the SiC substrate. Microfocal spectroscopic ellipsometry mapping of the electronic properties and thickness of epitaxial graphene on 3C-SiC (1 1 1) is also reported. Growth of one monolayer graphene is demonstrated on both Si- and C-polarity of the 3C-SiC substrates and it is shown that large area homogeneous single monolayer graphene can be achieved on the Si-face substrates. Correlations between the number of graphene monolayers on one hand and the main transition associated with an exciton enhanced van Hove singularity at similar to 4.5 eV and the free-charge carrier scattering time, on the other are established It is shown that the interface structure on the Si- and C-polarity of the 3C-SiC (1 1 1) differs and has a determining role for the thickness and electronic properties homogeneity of the epitaxial graphene.

1 - 48 of 48
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf