Mn3O4/PbS thin films: preparation and effect of annealing temperature on some selected properties

Abstract

Chemical bath deposition was applicable in the deposition of Mn3O4/PbS thin film. The structural, morphological and optical properties of the deposited films showed significant improvement with increase in annealing temperature. X-ray diffraction (XRD) studies showed increase in grain size with increase in annealing temperature. XRD analysis also show the existence of sharp and multiple peaks indicating the polycrystalline nature of the film. The existence of Pb2MnO4 phase was also observed in the XRD patterns. Scanning electron microscope (SEM) results showed increase in grain size and uniformity of grain surface as temperature increases. Optical studies reveal modification in the optical and solid state parameters with increase in annealing temperature. The absorbance increased with annealing temperature exhibiting a maximum in the UV region. Transmittance decreased with annealing temperature exhibiting a minimum in the UV region. The absorption coefficient varied from (0.5–1.5) × 10−4 cm−1 for the as-deposited to (0.5–3.5) × 10−4 cm−1 for the annealed at 473 K and (1.5–5.5) × 10−4 cm−1 for the annealed at 673 K. The band gap decreased from 3.95 eV for the as-deposited to 3.80 eV for annealed at 473 K to 3.70 eV for annealed at 673 K. The high energy gap implies that the thin film can be used for wide variety of applications in solar architecture.