Investigation of porous ZnSe thin films prepared by thermal evaporation

Abstract

Abstract ZnSe films with thickness of 50, 70 and 100 nm were prepared on Corning 7059 glass substrates at room temperature by applying continuous or periodically interrupted physical vapour deposition at very low deposition rates (0.2 and 0.5 nm s−1). Part of the films was annealed at 200 °C after deposition. Optical absorption spectra determined from spectroscopic ellipsometry data show direct allowed transitions, which indicate that the films have microcrystalline structure. This is in agreement with scanning electron microscopy and atomic force microscopy results. The spectroscopic ellipsometry results also show that the porosity of the films is strongly affected by both manner of deposition and deposition rate; the annealing causes some porosity decrease. Optical transmission spectra reveal that the transmittance of as-deposited films, obtained by periodically interrupted manner is significantly influenced by their porosity.