Analysis of glow curve of GaS_0.5Se_0.5 single crystals

Abstract

Characterization of shallow trapping centers in GaS0.5Se0.5 crystals grown by a Bridgman method was carried out in the present work using thermoluminescence (TL) measurements performed in the low temperature range of 10-300 K. The activation energies of the trapping centers were obtained under the light of results of various analysis methods. The presence of three trapping centers located at 6, 30 and 72 meV was revealed. The analysis of the experimental glow curve gave reasonable results under the model that assumes slow retrapping which states the order of kinetics as b=1. Heating rate dependence of the observed TL peaks was studied for the rates between 0.4 and 1.0 K/s. Distribution of the traps was also investigated using an experimental technique based on the thermal cleaning of centers giving emission at lower temperatures. The distributed levels with activation energies increasing from 6 to 136 meV were revealed by increasing the stopping temperature from 10 to 52 K. (C) 2015 Elsevier B.V. All rights reserved.