PHOTOLUMINESCENCE OF THE CR3-ZNAL2S4-CR SINGLE-CRYSTALS( IONS IN ALPHA)

Photoluminescence measurements have been performed on chromium doped a lpha-ZnAl2S4 spinel-type crystals in the temperature range 2-540K. a s ingle configuration coordinate diagram for the Cr3+ ions in the alpha- ZnAl2S4 host is constructed to interpret the absorption and emission s pectra and to allow a determination of the energy gaps between the (2) E(g) - T-2(1g) and (2)E(g) - T-4(2g) states. A fit of the measured tem perature dependence of the luminescence decay, using a simplified four level model gave the lifetimes of the (2)E(g), T-2(1g) and T-4(2g) ex cited levels and confirmed the gap values obtained from steady state m easurements. Copyright (C) 1996 Published by Elsevier Science Ltd