Effects of thiourea concentrations on the structural, morphological and optical properties of lead sulphied thin films prepared by solution growth method

Abstract

Chemical bath deposition (CBD) route employed to deposit lead sulphied (PbS) thin films at a bath temperature of 60 ⁰C for 40 minutes. The influence of applying different amount of thiourea concentration on the optical, morphological, structural properties of the deposited PbS films were studied. The prepared thin films were uniform, smooth and well adherent. The synthesized films were preferentially orientation along the (111) plane with face centered cubic crystal structure. The XRD studies showed that the lattice strain and dislocation densities of the synthesized PbS films decreased with increasing thiourea concentrations. The surface morphology study confirmed that as the thiourea molar concentrations increased the grains became enhanced. The EDS maps of PbS thin films revealed that the Pb and S elements were homogenously distributed on the surface of the thin films. The FTIR analysis of PbS nanocrystals revealed the presence of Pb-S vibration of Pb-S bonds observed around 613 cm^-1. The optical band gap estimated from UV-Vis analyses was found in the range of 0.82 eV to 0.98 eV.