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Proceedings Paper

Construction of photoconductivity measurement system as functions of excitation wavelength and temperature: application to Eu2+-activated phosphors
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Paper Abstract

In order to understand the thermal quenching of rare-earth doped phosphors, the clarification of electronic energy structure of excited states is an important step. As an experimental approach, the photoconductivity measurement of the phosphor is one of the effective methods to clarify the direct interaction of the excited electron (hole) and conduction- (valence-) band. In this study, we constructed an automatic measurement system of photoconductivity in inorganic phosphors. The wavelength- and temperature- dependence of the photocurrent in a Eu2+: SrAl2O4 phosphor was measured by using this system. Excitation wavelength dependence of photocurrent showed a similar profile to the PL-excitation spectrum of Eu2+. The result clearly indicates interaction of 5d level of Eu2+ with the conduction band. The activation energy of the photocurrent was evaluated from its temperature dependence for each wavelength. It decreased with wavelength from 490nm to 400nm, and became constant (~20 meV) below 400 nm. The ground state of Eu2+ (8S7/2) was estimated to be 3.1 eV below the bottom of the conduction band.

Paper Details

Date Published: 25 February 2010
PDF: 8 pages
Proc. SPIE 7598, Optical Components and Materials VII, 759809 (25 February 2010); doi: 10.1117/12.840110
Show Author Affiliations
Takayuki Nakanishi, Kyoto Univ. (Japan)
Setsuhisa Tanabe, Kyoto Univ. (Japan)

Published in SPIE Proceedings Vol. 7598:
Optical Components and Materials VII
Shibin Jiang; Michel J. F. Digonnet; John W. Glesener; J. Christopher Dries, Editor(s)

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