Effect of Complexing Agent on the Optical Properties of Zinc Sulphide (ZnS) thin films using Chemical Bath Deposition.

Abstract: Zinc sulphide thin films were deposited at room temperature by chemical bath deposition technique. The films deposited are highly uniform but poor in adherence. The optical properties were determined using the absorbance data measurement from M501 Single Beam Scanning UV/Visible Spectrophotometer at normal incidence of light, in the wavelength range of 380nm-700nm. From the results, the transmittance and reflectance were calculated. The band gap energy obtained is in the range of 3.0-3.3eV for different variations of TEA, Time and NH3. The transmittance and reflectance increase at higher concentration of complexing agent-TEA whereas the absorbance decreases. The transmittance also increases with time of deposition. Their high transmittance makes them suitable for use as an aesthetic window glass and good material for selective coatings for solar cells. The thickness of the thin films was also found to increase with time of deposition and the concentration of complexing agent-TEA. Also increase in the NH3 concentration decreases absorbance. This study explores the impact of complexing agents on the optical properties of ZnS thin films fabricated via chemical bath deposition, with the goal of enhancing their performance for optoelectronic applications.

Keywords: Chemical bath, Complexing agent, thin films, Transmittance, ZnS.