Investigation of the Cd concentration upon the structure and optical properties of the Ge-Te-Cd chalcogenide thin films

Abstract

   This work presents a comprehensive study of the structural and optical properties of thin films prepared from chalcogenide composition  where by using method of thermal evaporation. Compounds were prepared in a direct melting method and then removed in ice water. A preliminary examination of samples doing by XRD diffractions, These samples have a poly crystalline structure. The results of topography study of prepared films showed that grains with increasing diameter were increased and the diameter of these grains increased with increasing cadmium concentration.

The transmission spectra was studied and the width of band gap for all samples determined in the rang (400-1500nm). The width of band gab was increase by increasing the concentration of cadmium, and the Urbach Energy was calculated and a decrease in its values was observed, this was explained by the increase of crystalline structure of studied samples. The refractive index is also determined, and The coefficient of extension, and the real and imaginary part of the dielectric constant.