Influence of electron beam irradiation on structural and optical properties of thermally evaporated GeTe thin films

The effects of electron beam irradiation on optical and morphological properties of germanium telluride (GeTe) thin films, prepared by thermal evaporation technique, were investigated. The surface morphology, optical band gap, refractive index and extinction coefficient of these films were analyzed before and after exposure to electron beam irradiation. Optical analysis by absorption spectroscopy showed that irradiation modifies the optical band gap. Morphological studies through atomic force microscopy (AFM) analysis showed an apparently uniform growth of as deposited GeTe grains. Irradiation at lower dose resulted in increase in surface roughness and at higher dose it decreased again.