Optical characteristics of thermally evaporated GeSe2-Sb2Se3-ZnSe amorphous thin films

Amorphous thin films from the pseudo-ternary GeSe2-Sb2Se3-ZnSe system were prepared by vacuum thermal evaporation. The film composition was determined by profile Auger analysis, the morphology and the structure-by atomic force microscopy and electron microscopy. The optical transmission and reflection were investigated in the spectral region 300-2500 nm. The optical characteristics were calculated-optical band gap (ΔEg,opt), spectral distribution of the absorption coefficient (α), refractive index (n), extinction coefficient (ĸ), real part (ɛ′) and imaginary part (ɛ″) of the dielectric permitivity (ɛ). Correlation between the optical, the dielectric characteristics and the glass composition was discussed.