Optical, morphological and electrical studies of Zn:PbS thin films

Abstract

Structural, electrical, and optical properties of undoped and Zn doped lead sulfide (PbS) thin films are benign reported in this paper. The subjected films were grown on glass substrates at 25°C by a chemical bath deposition (CBD) method. The concentration of Zn in the deposition bath represented by the ratio [Zn2+]/[Pb2+] was varied from 0% to 5%. It was found that the film׳s grains decreased in size with increasing Zn content in the film. XRD data showed the polycrystalline nature of the film its crystal orientation peak intensities decreased with higher doping concentration of Zn. Atomic force microscopy (AFM) measurements revealed that the surface roughness of the films decreased due to zinc doping as well. However, with increasing of the dopant concentration from 0% to 5%, the average transmittance of the films varied over the range of 35–75%. The estimated optical band (Eg) gaps of undoped and Zn doped PbS thin films were in the range of 0.72–1.46eV. Hall Effect measurements electrical resistivity, carrier concentration and Hall mobility have been determined for the titled film as functions on the Zn content within the film׳s textures. The overall result of this work suggested that the Zn:PbS film is a good candidate as an absorber layer in the modern solar cell devices.