Chemical deposition of CdS thin films in the hexagonal phase without annealing

Abstract

Cadmium sulfide (CdS) thin films were produced using the chemical bath deposition method with thiourea as the source of sulfur (S). Cadmium chloride (CdCl2) (2.4 mmol), potassium hydroxide (KOH) (0.15 mol) and ammonium nitrate (NH4NO3) (0.16 mol) were dissolved in 100 ml deionized water. Thiourea was added to the final solution at intervals of 0, 1.5, 3.0, 6.0 and 9.0 min. The effects of delaying the addition of thiourea were investigated. The optical properties of cadmium sulfide thin films were determined using an ultraviolet–visible spectroscopy machine. It was found that the bandgaps of the films decreased as the delay time of adding thiourea increased. The structural properties of the cadmium sulfide thin films were obtained by X-ray diffraction. It was discovered that when the film was created with a delay time of 6 min, it had a hexagonal structure. Surface analysis of all the thin films was done with a scanning electron microscope. It was found that cracks and voids decreased as the delay time of the thiourea addition increased.