The optical properties of Se85.26Ge12.92Cd1.81 thin films on different substrates.

Abstract

Se85.26Ge12.92Cd1.81 thin flms were prepared using glass and fuorine tin oxide FTO substrates by the technique of thermal evaporation. Structure was performed using X-ray diffraction pattern and the energy dispersive X-ray analysis EDX. The optical properties of Se85.26Ge12.92Cd1.81 thin flms are investigated by spectrophotometric measure of transmission, refectance and absorbance at normal incidence of light in the wavelength range 300–2500 nm. There are two types of optical transition direct and indirect allowed for both flms deposited on to glass and FTO substrates. Values of both absorption index (k) and the refractive index (n) are calculated. The energy gap value Eg opt for Se85.26Ge12.92Cd1.81 flms deposited on FTO substrates found to be smaller than its value for flms deposited on to glass substrates. The optical dispersion parameters, E0, Ed, n(0), λ0, S0 and n∞ 2 were also determined and discussed.