Preparation of nanocrystalline Sb doped PbS thin films and their structural, optical, and electrical characterization

Nanocrystalline Sb doped PbS thin films have been deposited by chemical bath deposition technique. After deposition, the films have been annealed at 673 K for 1 h in air. The X-ray diffraction (XRD) pattern of the films shows the formation of well crystallized PbS with face centered cubic structure with the preferential orientation (2 0 0). The values of average crystallite size have been found to be in the range 40-43 nm. AFM surface analysis indicates a uniform and smooth surface with average grain size of 52.3 nm. The optical properties, absorption, and transmission of the films, as a function of doping have been measured. The increase of Sb doping in PbS thin films leads to decrease of band gap Eg from 1.69 eV to 1.59 eV, which satisfied on blue shift of the absorption edge in nanostructured thin films. The measured room temperature electrical resistivity of the films is in the range 1.29-3.7 × 106 Ω cm.