STUDY THE EFFECT OF THICKNESS ON STRUCTURAL AND OPTICAL PROPERTIES OF ZNO THIN FILMS DOPED WITH 7% CADMIUM PREPARED BY CHEMICAL SPRAY PYROLYSIS METHOD

Abstract

ZnO thin films, pure and doped with cadmium in rate of (7%) and with thickness equal to (300,500,700) nm, have been prepared by using chemical spray pyrolysis technique on glass substrates with temperature about (375 ± 5 C). Using the solution of zinc acetate with (0.2 M), the ZnO films doped with Cd have been obtained from the addition of cadmium acetate to zinc acetate with (0.2M) too. Structural and optical properties of the thin films above have been studied; XRD measurements demonstrated that the pure ZnO and (ZnO:Cd) films are polycrystalline with (100) orientation and with Hexagonal Wurtzite structure. Furthermore ,crystallized of films increasing with increase of thickness. The optical properties were studied using the spectral of the absorbance and transmission of films in wavelength ranging (300-800) nm. The study showed that the films have high transmission within the range of the visible spectrum and decrease with increase thickness and doping with cadmium, In addition changing in edge of absorbance to high wavelengths, which confirms the decrease in the values for the energy gap. Also absorption coefficient and coefficient of extinction was calculated and found to be changed with thickness changing