Molecular structure and quenching of photodarkening in As2Se3:Snx amorphous films

摘要

Photodarkening relaxation under light exposure of a-As2Se3amorphous films and doped with 0.5-5.0 at.% Sn were studied for their dependence on the concentration of impurities and thermal treatment. It was shown that both factors reduce photodarkening with the degree of reduction dependent on the concentration of impurity and temperature of heat treatment. The relaxation process of photodarkening is described by a stretched exponential with the dispersion parameter 0<α<1.0, and time constant increasing with tin concentration or thermal annealing. The case of Sn in As2Se3glass was probed by a local probe like 119Sn M.ssbauer spectroscopy, and in conjunction with Temperature Modulated Differential Scanning Cal orimetry (MDSC) some aspects of the molecular glass structure were elucidated. On the basis of the structure results and photodarkening ones the molecular origin of light-induced effects in Sn-doped As2Se3was revealed