Emission properties and local structure of TM3+ in Ge-Ga-S-Br glass

Abstract

Spectroscopic properties of TM3+ in (1 - x) (Ge0.25Ga0.10S0.65)-xBr (or CsBr) glasses (x = 0.0 and 0.1) were investigated. Emission properties of Tm3+ in 0.9(Ge0.25Ga0.10S0.65)-0-1CsBr glass were similar to those in Ge(,.25Gao.10S0.65 glass, while there was significant improvement when doped into 0.9(Ge0.5Ga0.10S0.65)-0.1CsBr glass. The lifetime of the TM3+:(3) H-4 level increased from 0.23 to 1.22 msec with 10 mol% CsBr addition. The presence of Cs+ facilitated the formation of [GaS3/2Br](-) units by donating an electron to the Ga tet- rahedron, resulting in the homogeneous distribution of Br. In this way, TM ions have their local environment made of Br only. When Br ions were added instead of CsBr, [GaS(4-x)/2Br](-) units with x > 1 were formed and TM3+ ions were surrounded by both S and Br, producing a high phonon environment. (C) 2007 Elsevier B.V. All rights reserved.