Parameterization of photobleaching and photodarkening in-situ kinetics in thermally deposited GeSe2 thin films

Abstract

Thermally evaporated chalcogenide glass thin films are known to be highly photosensitive revealing both metastable and transient photoinduced changes of optical transmission at the fundamental absorption edge region. In-situ kinetics of metastable photobleaching and transient photodarkening as well as following light-off relaxations for as-deposited GeSe2 thin films were studied and fitted with the stretched exponential function. Dependences of kinetic parameters beta and tau a on film thickness, temperature, sample prehistory and wavelength of light irradiation were analyzed. The obtained results were discussed within current approaches to mechanisms of photoinduced kinetic phenomena and structural relaxation in glasses.