Preparation and properties of CdS thin films deposited by chemical bath deposition

In this work, a systematic research on the relationship between the CdS crystalline structures and pH value of the solution and annealing treatments for the CdS thin films were carried out. CdS thin films were deposited on ITO substrates by chemical bath deposition methods at a certain bath temperature, in which the CdAc2 and H2NCSNH2 were used as starting materials. During the reactions, NH3H2O was used to control pH value of the solutions. Morphological, structural and optical properties of the CdS films were investigated using scanning electron microcopy (SEM), X-ray diffraction and UV–vis spectrophotometer, respectively. As the pH value increased up to 10.5, CdS film showed the best crystallinity accordingly. From the diffraction patterns, the crystallite sizes were found to increase with increasing annealing temperature. The obvious blue-shift of those annealed with CdCl2 compared with those directly annealed was conducive to improve the efficiency of CdS/CdTe solar cell.