Charge transfer processes in CsI

Tl using near-UV light

V. Yakovlev, L. Trefilova, A. Meleshko, V. Alekseev, N. Kosinov

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

This paper studies charge transfer processes in CsI:Tl crystals by analyzing the bulk photo-conductivity spectra, the temperature behavior of the bulk photo-conductivity current and the shape and intensity of the activator emission pulse excited by an electron pulse beam and/or laser pulse emission at temperatures between 80 and 400 K. The Tl concentration in CsI:Tl crystals varies from 10-3-10-1 mass%. It has been determined that near-UV light induces a bulk conductivity in CsI:Tl crystals only when the Tl concentration is greater than 3×10-3 mass%. A mechanism is proposed to explain the charge transfer processes with photons whose energy is approximately half the width of the CsI band gap. Near-UV light causes charge transfer from I- to Tl+ ions, forming Tl0 centers in the 6p2P1/2 ground and 6p2P 3/2 excited states. The electron, assisted by phonons, leaves the Tl0 center from either the 6p2P1/2 or 6p 2P3/2 states and overcomes the 0.13 or 0.30 eV energy barrier, respectively, and subsequently populates the activator conduction sub-bands, which are found inside the band gap of CsI:Tl. The formation of activator sub-bands is possible only above the threshold Tl concentration, i.e., above 3×10-3 mass%.

Original languageEnglish
Pages (from-to)79-83
Number of pages5
JournalJournal of Luminescence
Volume155
DOIs
Publication statusPublished - 1 Jan 2014

Fingerprint

Ultraviolet Rays
Ultraviolet radiation
Charge transfer
Phonons
charge transfer
Electrons
Crystals
Temperature
Laser pulses
Energy gap
Photons
conductivity
Lasers
pulses
Energy barriers
Ions
crystals
Excited states
leaves
phonons

ASJC Scopus subject areas

  • Biophysics
  • Atomic and Molecular Physics, and Optics
  • Chemistry(all)
  • Biochemistry
  • Condensed Matter Physics

Cite this

Charge transfer processes in CsI : Tl using near-UV light. / Yakovlev, V.; Trefilova, L.; Meleshko, A.; Alekseev, V.; Kosinov, N.

In: Journal of Luminescence, Vol. 155, 01.01.2014, p. 79-83.

Research output: Contribution to journalArticle

Yakovlev, V. ; Trefilova, L. ; Meleshko, A. ; Alekseev, V. ; Kosinov, N. / Charge transfer processes in CsI : Tl using near-UV light. In: Journal of Luminescence. 2014 ; Vol. 155. pp. 79-83.
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