Performance analysis of P-SnS thin films fabricated using CBD technique for photo detector applications

Abstract

In the present work, SnS thin films were prepared using the CBD technique at room temperature and varying annealing temperaturesfrom300 to 450 °C for photo detector applications. The prepared samples were characterized using different techniques for analyzing the structural, optical, morphological, and photo sensing properties of the samples. From XRD analysis, the diffraction pattern of all the prepared thin films shows the pristine SnS phase of the samples possessing an orthorhombic phase without the presence of any impurity phases. Among the fabricated thin films, the SnS thin film annealed at a temperature of 350 °C reveals the highest crystallite size. The Raman results showed the vibrational modes of SnS films and with the increase in growth temperature, the peaks are slightly shifted towards the lower wavelength region. Morphological results show that the SnS thin films exhibit a uniform morphology of 2-D petal-like morphology with different sizes. The UV-vis spectroscopic study shows the decrease in the bandgap value of the samples with the increase in annealing temperature. The photo sensing properties of the fabricated samples show the SnS sample annealed at 400 °C has a higherresponsivityvalueof6.40×10⁻²AW⁻¹,externalquantumefficiency(EQE)valueof14.9%, and the detectivity value of 6.05 × 10⁹ Jones. Finally, the transient photo response results suggest that the SnS annealed at 350 °C shows a rise and fall time of 1.5 and 2.5 s compared to the othersampleswhichwouldbebettersuitedforphotodetectorapplications. The electrical conductivity and photo-conductivity of the films increase by more than two orders with increase of film thickness from 170 nm to 915 nm. Hall Effect measurements confirm the p-type nature of the as-prepared SnS thin films.