OPTICAL AND PHOTOELECTRICAL PROPERTIES OF (CdTe)100-x(SbSe)x THIN FILMS

摘要

This work deals with the effect of the addition of SeSb on the optical constants and the photoconductivity of polycrystalline (CdTe)100-x(SbSe)x (0 ? x ? 28 at.%) thin films. Increasing SeSb content is found to affect the dispersion parameters and energy gap of the films. The transmission spectra, T(λ), of the films at normal incidence were obtained in the spectral region (400-2500 nm). A straightforward analysis proposed by Swanepoel, based on the use of maxima and minima of the interference fringes has been applied to derive the complex index of refraction (real and imaginary parts) and the films thickness with high accuracy. The optical absorption is due to allowed direct transition with energy gap decreases from 1.58 to 1.33 eV with increase of the SeSb content from 0 to 28 at. %. Both of Wemple–DiDomenico and Solomon dispersion relationships were used to obtain the dispersion parameters of the films. The composition dependence of steady state dark and photo conductivities at room temperature shows that the dark and the photo conductivities increase while the activation energies for dark and photoconduction decrease with increase of the SeSb content.