Effect of pH on structural, optical, and morphological properties of ED-CdTe film

Abstract

Abstract Cadmium telluride (CdTe) thin films have been deposited by electrodeposition (ED) technique on fluorine doped tin oxide (FTO) coated glass substrates using an aqueous electrolyte bath solution. The pH-value of the electrolyte solution is one of the most important deposition parameter that should be optimized to achieve high quality photoconductive material. The films have been deposited at different pH values ranging from 1.5 to 3. The structural, optical, and morphological properties of the samples were characterized using X-ray diffraction (XRD), UV– Visible (UV-Vis) spectroscopy, spectroflurophotometer, scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDX) techniques respectively. The XRD analysis shows that the ED-CdTe films possess the cubic crystalline structure and the diffraction peak intensity increased significantly after changing the pH values. The direct energy band-gap (Eg=1.44eV) is obtained in optical absorption spectra. The SEM analysis shows very good morphological growth by changing the pH values and the film deposited with lower pH showed more intense PL emission peaks as compared to the other two films. CdTe film deposited at pH 1.5 will be better choice as an absorber layer of a CdTe/CdS solar cell.