DYNAMICS OF PHOTODARKENING IN AMORPHOUS CHALCOGENIDES

We review the recent advances made in understanding the dynamics of photoinduced structural changes (PSC) and photodarkening (PD) in amorphous chalcogenides. The new results of the occurrence of transient and metastable changes in PSC and PD have shed new light in understanding the mechanism of these changes. We present measurements of these metastable and transient effects in evaporated films of a-chalcogenides. The results are discussed in terms of a macroscopic model in which, on photoexcitation, layer- or chain-like clusters of atoms are expected to expand and slip relative to each other