Crystallization effects in annealed thin Ge–Se films photodiffused with Ag

Ge–Se glasses with composition ranging from Ge20Se80 to Ge40Se60 photodoped with Ag and annealed at moderate temperatures are investigated. Raman spectroscopy suggests that Ag photodiffusion brings about the formation of a Ge–Se backbone that is deficient in Se and that the structure is depolymerized due to the extraction of Se during the formation of crystalline products. X-ray diffraction shows that after Ag diffusion into the glass, nanocrystals of Ag2Se and Ag8GeSe6 form, depending on the composition of the host. The crystal size is affected by the molecular clustering of the host.