Study of the Optical properties for CdS thin film before and after irradiated by CO₂ laser

Abstract

In this study CdS thin film was prepared by using thermal vacuum evaporation technique under the pressure (10⁻⁶) torr on glass substrate at room temperature. Samples was irradiation to CO₂ laser of power (1 watt) and wave length (10.6) µm at distance 10 cm from the source during (5sec). The absorbance spectra was recorded using UV-visible spectrophotometer and used to calculated some of optical properties which include their transmittance, reflectance spectra, energy gap, absorption coefficient α, extinction coefficient the refractive index n and the real part and imaginary part of dielectric constant. From the result of thin films samples we can conclude that irradiation CdS thin film by CO₂ laser due to increased in reflectance R, absorption coefficient α, the extinction coefficient K, the refractive index n and the real part and imaginary part of dielectric constant while irradiation cause decrease in the transmittance T and in the Eg value of the energy gap.