Performance analysis of SnS thin films fabricated using thermal evaporation technique for photodetector applications

Abstract In the present work, SnS thin films were prepared using the thermal evaporation technique at room temperature and varying annealing temperatures from 200 to 350 °C for photodetector applications. The prepared samples were characterized using different techniques for analyzing the structural, optical, morphological, and photosensing 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 300 °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 photosensing properties of the fabricated samples show the SnS sample annealed at 300 °C has a higher responsivity value of 6.40 × 10-2 AW-1, external quantum efficiency (EQE) value of 14.9%, and the detectivity value of 6.05 × 109 Jones. Finally, the transient photoresponse results suggest that the SnS annealed at 300 °C shows a rise and fall time of 1.5 and 2.5 s compared to the other samples which would be better suited for photodetector applications.