Studies on Lead Sulphide (PbS) Thin Film Prepared by Chemical Bath Deposition Method

Abstract

Lead Sulphide, PbS thin films deposited on glass substrates by a chemical bath deposition method, which is a simple and easily controlled technique. The reactive substances used to obtain the PbS layers were (Pb(NO3)2), NaOH, Sc(NH2)2 and H2O for different dipping concentrations of lead nitrate, dipping times and temperatures. The films were structurally characterized by X-ray diffraction studies. The films are very adherent to the substrate and well crystallized according to the face centered cubic structure with the preferred orientation (1 1 1). The films were optically characterized by the transmission and reflectance spectrum, examined by a UV – VIS Spectrophotometer. In the infrared range, low transmittance and reflectance are detected (between 10% and 30%), while there is no transmittance or reflectance in the UV and visible regions. It can be seen from absorption spectra that absorption is stronger in the UV and UV-VIS region and gradually diminishes. Maximum absorption is observed in the visible and ultraviolet range, which indicates that the film prepared is of nanocrystalline. The band gap of PbS can be varied in the range of 0.41 to 2.71 eV, which is a significant material feature and opens the door to a new class of applications. The calculated band gap was determined to be between 1.88eV and 2.1eV.