Optical Constants and Dispersion Parameters of CdS Thin Film Prepared by Chemical Bath Deposition

Abstract

CdS thin film was prepared on glass substrate by chemical bath deposition in an alkaline solution. The optical properties of CdS thin film were investigated using spectroscopic ellipsometry. The real (<TEX>${\varepsilon}_1$</TEX>) and imaginary (<TEX>${\varepsilon}_2$</TEX>) parts of the complex dielectric function <TEX>${\varepsilon}(E)={\varepsilon}_1(E)+i{\varepsilon}_2(E)$</TEX>, the refractive index n(E), and the extinction coefficient k(E) of CdS thin film were obtained from spectroscopic ellipsometry. The normal-incidence reflectivity R(E) and absorption coefficient <TEX>${\alpha}(E)$</TEX> of CdS thin film were obtained using the refractive index and extinction coefficient. The critical points <TEX>$E_0$</TEX> and <TEX>$E_1$</TEX> of CdS thin film were shown in spectra of the dielectric function and optical constants of refractive index, extinction coefficient, normal-incidence reflectivity, and absorption coefficient. The dispersion of refractive index was analyzed by the Wemple-DiDomenico single-oscillator model.