Effect of pH-11 Buffer as Agent Reaction Moderator in the Growth and Characterization of CdS Thin Films by CBD Technique

Abstract

The effect of deposition parameters of CdS thin films developed by Chemical Bath Deposition (CBD) technique was investigated in this paper. We studied the influence of pH control of the reaction solution on the structural and optical properties of chemically deposited CdS films. Different films thicknesses of CdS were deposited onto a glass substrate. The structural surface morphology of as-deposited CdS thin films was characterized by SEM, XRD, profilometer, and ultraviolet–visible spectroscopy. The physical conditions were kept identical while growing the samples. The investigation of the effect of the synthesis method on the change the ammonium hydroxide by buffer pH-11 contributed in increases the growth kinetics, resulting in thicker films. Over the years, thin films of II-VI semiconductor compounds are most promising for utilization in solar cells, out of which the cadmium sulfide (CdS) has received intensive attention, since its band gap lie very close to the range of maximum theoretically attainable energy conversion efficiency. CdS is an inorganic compound of yellow solid color, and due to its wide band gap, photoconductivity, and high electron affinity, is known to be an excellent heterojunction partner for p-type cadmium telluride, p-type copper indium diselenide. It has been widely used as a window material in high efficiency thin film solar cells based on cadmium telluride or copper indium diselenide [1-3]. In these devices, light penetrates the CdS layer and it is absorbed in the p-type semiconductor close to the pn junction. Also, CdS is an interesting crystal material in the area of photodetectors, semiconductor lasers, and non linear integrated optical devices. The importance of wide band gap materials is related to the possibility of fabricating light emitting diodes or laser heterostructures for emission in the visible spectral range. The CdS thin films were fabricated by CBD technique on glass substrate. The diffractogram of an