THE INFLUENCE OF THICKNESS ON THE OPTICAL PARAMETERS OF THERMALLY EVAPORATED PURE AND SILVER-DOPED CADMIUM SELENIDE THIN FILMS

Abstract

Silver doped CdSe thin films has been prepared by thermal evaporation in different proportions (0, 3, 5, and 10) wt.% .Pure cadmium selenide (CdSe) films sediment with different thicknesses (200,218,225,254) nm on glass substrates at room temperature. The results of the measurements through the studying of the optical properties showed that the absorbance of the (CdSe) films increase within the thickness of the film and the distortion ratios for the wavelengths located within the visible region of the electromagnetic spectrum. It also showed that the absorption coefficient of all the prepared films was a value greater than (α >104 𝑐𝑚-1) and that this value increases in general with increasing thickness and distortion ratios, especially at low photonic energies. the results showed as for the value of the optical energy gap, that the films have (CdSe) all direct optical energy gap and its values decrease from (1.76 eV) to (1.73 eV) with increasing thickness. As for the defective films, their value decreases from (1.73 eV) to (1.66 eV) with an increase in the doping percentage.