Thermal quenching of photoluminescence in GeSe2 glass, thin films and crystals

Abstract Investigations were carried out on the temperature dependence of the photoluminescence intensity and the emission band characteristics in GeSe 2 glasses, evaporated thin films and crystals at T >80 K, paying special attention to the fatigue taking place 20–50 s from the onset of excitation. From the temperature dependence of the initial and quasi-steady-state values of the PL intensity an activation energy 295−30 meV at T >210 K was deduced for the glass whereas two activation energies E 1 =56±2 meV and E 2 =96±3 meV were deduced for the crystalline GeSe 2 . The strong fatigue observed in the evaporated thin films was attributed to their loose structure. The fast fatigue in the crystal was considered to result from the recombination of quasi-excitons through radiative and non-radiative channels. A configuration coordinate diagram involving a stable and a metastable state is proposed as a means of explaining this type of fatigue. The temperature dependence of the PL intensity is discussed in terms of a recently proposed model.