Optical Properties of PbS/CdZnS Double Layers Nanocrystalline Thin Films for Opto-Electronic Applications

Abstract

In this work, three samples of thin films were prepared from semiconducting nanomaterials by the chemical bath method, where a thin film of lead sulfide PbS, Cadmium zinc sulfide CdZnS and PbS/CdZnS was prepared. The optical properties and surface formation of the bilayer film were studied and investigated by scanning electron microscope and UV–Visible spectrometer. It was observed through the scanning microscope image that the surface of the thin film is composed of CdZnS material in the form of nanowalls that cover the PbS nanoparticles completely, forming a core–shell structure. The transmittance and absorption spectra of the prepared films, as well as the direct and indirect energy gaps, were measured. It was observed that there is a shift in the absorption and transmission spectra of the PbS film after coating it with CdZnS layer. The magnitudes of the direct and indirect energy gaps of the bilayer film are 1.8[Formula: see text]eV and 1.5[Formula: see text]eV, respectively.