Charge transfer processes in CsI:Tl using near-UV light
| Parent link: | Journal of Luminescence Vol. 155.— 2014.— [P. 79-83] |
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| Korporativní autor: | |
| Další autoři: | , , , , |
| Shrnutí: | Title screen 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 6p2P3/2 excited states. The electron, assisted by phonons, leaves the Tl0 center from either the 6p2P1/2 or 6p2P3/2 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%. Режим доступа: по договору с организацией-держателем ресурса |
| Vydáno: |
2014
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| Témata: | |
| On-line přístup: | http://dx.doi.org/10.1016/j.jlumin.2014.05.019 |
| Médium: | Elektronický zdroj Kapitola |
| KOHA link: | https://koha.lib.tpu.ru/cgi-bin/koha/opac-detail.pl?biblionumber=652775 |
| Shrnutí: | Title screen 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 6p2P3/2 excited states. The electron, assisted by phonons, leaves the Tl0 center from either the 6p2P1/2 or 6p2P3/2 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%. Режим доступа: по договору с организацией-держателем ресурса |
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| DOI: | 10.1016/j.jlumin.2014.05.019 |