Effect of annealing on structural, morphological and optical properties of CdTe/(Cd-Zn)S thin films

Abstract

Abstract Here, we present the results of an investigation on structural, morphological and optical properties of CdTe/(Cd-Zn)S films deposited on FTO substrate through electrodeposition technique for solar cell application. The deposited films were heat-treated in the presence of CdCl2 for the recrystallization. Various techniques, such as X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), optical studies (absorption, transmission, band-gap and photoluminescence studies) were employed to examine the structural, morphological and optical properties. XRD spectra show the preferential orientation (111) in CdTe films. Uniform and bounded grains are observed upon annealing of the films. The changes in CdTe film were attributed to nucleation of the CdTe grains during the CdCl2 treatment. The band-gap (Eg) value for CdTe estimated from absorption spectra and corresponding Tauc’s plots comes to be ~1.50eV. Summary of results suggests that the annealing of different component films is helpful in improving solar cell performance.