Effect of Deposition Time on Structural and Optoelectronic Properties of Flower-Like Nanostructured PbS Thin Films

Abstract

Polycrystalline nanostructured PbS thin films are deposited onto soda-lime glass substrates by the method of chemical bath deposition (CBD) at different duration of deposition time. The structure and surface morphology of the films are characterized by X-ray diffraction (XRD) and field effect scanning electron microscopy (FE-SEM). XRD pattern exhibits polycrystalline structure with preferential orientation along (200) direction, parameters such as crystallite size, lattice constant, lattice-strain and dislocation density are calculated. The FE-SEM images show appearance of flower like structure on formation of PbS films which is indicative of suitability in gas sensing applications. Studies on optical properties carried out by UV-Vis spectroscopy measurements show bandgap in the range 1.65eV – 1.41eV. The photoluminescence spectra of the films exhibit two peaks centered at around 613 nm and 738 nm after excitation at 450 nm. Electrical studies from Hall measurements indicate the carrier concentration and mobility of the PbS samples corroborate the variations in the conductivity.