Effects of Deposition Time on the Morphology, Structure, and Optical Properties of PbS Thin Films Prepared by Chemical Bath Deposition

Lead sulfide thin films were prepared by chemical bath deposition (CBD) on both glass and Si (100) substrates. XRD analysis of the PbS film deposited at 25°C showed that the prepared films have a polycrystalline structure with (200) preferential orientation. Larger grains could be obtained by increasing the deposition time. The prepared films were also chemically characterized using X-ray photoelectron spectroscopy (XPS), which confirmed the presence of lead and sulfur as PbS. While energy dispersive X-ray spectroscopy (EDX) technique was used to verify the stoichiometry of the prepared films. Atomic force microscopy (AFM) was used to study the change in the films' morphology with the deposition time. The effect of the deposition time, on both optical transmittance in the UV-Vis-NIR region and the structure of the film, was studied. The obtained results demonstrated that the optical band gap decreased when the thickness increased.