Enhancement of optoelectronic properties of PbS thin films grown by Jet nebulizer spray pyrolysis technique for photodetector applications: an impact of substrate temperature

Herein, the p–PbS/n–Si photodiodes were fabricated by the cost-effective jet nebulizer spray pyrolysis technique. The PbS thin films were deposited at various substrate temperatures from 225 to 300 °C. The impact of substrate temperature on PbS thin films has been systematically investigated by various characteristics techniques. X-ray Diffraction (XRD) reveals that the prepared films are polycrystalline crystal structures of cubic phase with preferential orientation along the (200) plane. Field Emission Transmission Microscopy (FESEM) results indicate that sphere-like morphology changed into a triangle shape with maximum grain size as substrate temperature increased. The energy dispersive X-ray analysis (EDS) with mapping images confirms the existence of Pb and S. The chemical composition of PbS thin films was investigated by X-ray photoelectron spectroscopy (XPS). The UV–Vis absorption spectrum revealed that the bandgap value increased from 2.2 to 2.5 eV by increasing the deposition temperature from 225 to 300 °C. The I–V characteristics of the p–PbS/n–Si diode showed better rectification in dark and outstanding photovoltaic properties when exposed to light. The photoresponsivity of the fabricated diode increased from 2.525 to 18.140 mA/W with increasing the light intensity from 40 to 120 mW/cm². Our findings showed that p-PbS/n-Si diodes based on PbS elements are promising for photodiode and ultraviolet photodetector applications.