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.