Effects of gamma irradiation on optical properties of CdS thin film

The effect of gamma-ray radiation on the optical properties of CdS thin film .Thin film were prepared by sol Gel technique .The investigated thin films of 1μm thickness are then irradiated by 25 kGy doses of 137CS(Half time 28 years ) gamma rays. The optical properties of prepared film have been studied using UV-VIS spectrophotometer in the wavelength range 300 nm-1100 nm. Optical constants, such as absorption, extinction coefficient , refractive index ,real and imaginary type of dielectric constant are calculated. The prepared films were found to be of direct energy gap found to be in the range of 2. 9eV before radiation and 2eV after radiation .