The Effect of doping on the optical properties of
CdS thin films prepared by spray pyrolysis
Abstract:
In this search , Cadmium sulphide (CdS) thin films were prepared by the chemical spray pyrolysis technique , films of (CdS) have been prepared as pure and doped by Copper (Cu) with different ratio (2%,4%).The films were deposited on glass slide from aqueous solutions cadmium chloride – CdCl2·2H2O, thiourea – SC(NH2)2 with molar ratio (0.05) at substrate temperature (3000C). The topographic properties of the surface thin films which are prepared by reflective optical microscope. As a consequence, the optical parameters of the films were determined by using spectrometer type (SHEMATZU), The optical properties were studied for range of wave length (300-1100nm).Transmission were (89%-83%), this ratio is depended on thickness and doping ratio of the films, where as transmission proportion reversely with increasing doping .The absorption coefficient is determined and correlated with the photon energy in order to estimate the direct transition energy band gap. Direct band gap values of 2.1 -2.6 eV were obtained.The refractive index and Extinction coefficient is reported on depending on the ratio of doping and was obtained from transmission spectra.From this reason ,the films doping can be useful to prepare CdS photovoltaic (solar cells).
