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Leif Jönsson

Leif Jönsson

Professor emeritus

Leif Jönsson

Separation of excitonic and electron-hole processes in metal tungstates

Author

  • V Nagirnyi
  • M Kirm
  • A Kotlov
  • A Lushchik
  • Leif Jönsson

Summary, in English

Absorption, reflection and emission polarization spectra of CdWO4 crystals have been studied in the region 3.5-30 eV in order to distinguish the excitonic and electron-hole processes in the vicinity of the band gap. The following parameters have been defined from the Urbach tail study at 6-300 K: E-0 = 5 eV, sigma(0) = 0.31, homega = 70 meV (565 cm(-1)). Excitonic processes have been shown to dominate at excitation of tungstate crystals in the lower part of the conduction band. Excitons are formed due to the transitions into the tungstate W5d states hybridized with O6p and possess a very strong tendency for self-trapping. Free electrons and holes can be created at the energies 1-2 eV (depending on the crystal) higher than the bottom of the conduction band due to the transitions into cationic states. (C) 2003 Elsevier Science B.V. All rights reserved.

Department/s

  • Particle and nuclear physics

Publishing year

2003

Language

English

Pages

597-603

Publication/Series

Journal of Luminescence

Volume

102

Document type

Journal article

Publisher

Elsevier

Topic

  • Subatomic Physics

Keywords

  • band structure
  • urbach rule
  • tungstates
  • absorption

Status

Published

ISBN/ISSN/Other

  • ISSN: 0022-2313