Electronic structure and optical band gap of silver photo-diffused Ge2Sb2Te5 thin film

► Amorphous chalcogenides were investigated in this work. ► Carried out photo-doping of Ag into Ge-Sb-Te films by illuminating thermally evaporated GST:Ag bilayer. ► Photo-induced silver diffusion effects were investigated in the created thin films. ► Increase in the optical band gap on silver photo-diffusion is due to decrease in the density of defect states.