Kinetics of photosensitivity in Ge-Sb-Se thin films

Chalcogenide (GeSe2)100-x(Sb2Se3)x thin films obtained using pulsed laser deposition are exposed to light with energy close to band gap energy, in order to investigate kinetics of photoinduced phenomena. It appears that a reversible transient photodarkening is observed. The metastable part of photodarkening, which seems to be slower, is followed by photobleaching. A modelling of the evolution of transmission during illumination suggests that each process has an independent effective time constant, and that magnitude of photoinduced phenomena depends on various parameters, such as laser's fluency, absorption coefficient and composition.