Photoluminescence Properties of Cu-doped GaSe

Photoluminescence spectra of undoped and Cu-doped crystals of the layered semiconductor GaSe have been measured in the temperature range from 80K to room temperature. The main modification of the spectra in doped crystals with respect to those of undoped samples is the appearance of two new bands and the enhancement of light emission. A detailed analysis of spectra, by varying excitation intensity and temperature, enabled the authors to analyse the defect levels involved in the transitions. A simple kinetic model for indirect free and bound excitonic transitions in doped samples is proposed