Structural and optical properties of cadmium telluride obtained by physical vapor deposition technique

Abstract

The structural and optical properties of cadmium telluride (CdTe) thin films prepared by thermal evaporation using physical vapor deposition technique and obtained under different process conditions (different deposition time) were investigated. CdTe thin films were obtained on (100) silicon and glass substrates. The analysis of atomic force microscopy images of surface revealed a certain periodicity of the objects’ location on the surface. After detailed analysis by autocorrelation functions, it has been established that the films have a clearly expressed periodicity along the axis OX, which is due to the orientation of growth on (100) Si substrate. The optical properties indicate a smooth film with nanoparticle size (25–28) nm on surface for both thin and thick films of CdTe. The optical transparency is observed in the short infrared radiation. An analysis of the optical properties was performed using the Swanepoel method. Hence, the basic properties of the films such as refractive index, film thickness, absorption coefficient and optical conductivity are determined. The optical transparency is observed in the short infrared radiation.