Optical properties of p-GaSe single crystals doped with Te

Optical absorption in the region of fundamental absorption edge and photoluminescence (at 78 and 293 K) of p-GaSe crystals doped with Te (0.05, 0.10, and 0.05 at. %) have been studied. At low concentrations (0.05 at. %), Te atoms liquidate structural defects in GaSe single crystals and modify their excitonic absorption and photoluminescence. For increased concentrations of 0.10 and 0.50 at. %, Te creates impurity states responsible for the red shift of the fundamental absorption edge of GaSe and appearance of new photoluminescence bands, B (at 2.000 eV) and C (at 1.700 eV). The activation energies of the thermal quenching of Te-related PL bands B and C was found to be 28 and 32 meV (for T < 150 K) and 84 and 62 meV (for T>150 K), respectively.