Terbium-doped SnS thin films: comprehensive physical and optoelectronic characterizations for the photodetector applications

Pure and SnS:Tb thin films at varying (1, 2, 3, 4, 5 wt%) Tb concentrations were synthesized using the nebulizer spray pyrolysis (NSP) technique at ambient temperature. The orthorhombic SnS phase was verified using the XRD studies. The incorporation of 2% Tb dopants indicates that the crystallite size was increased to 44 nm. The results of the AFM demonstrates that the developed samples are uniform in size, spherical, and nano-shaped. The UV–Vis spectroscopic investigation reveals strong absorption at the visible and NIR regions and a lower bandgap value of 1.75 eV for the SnS:Tb 2%. The P.L. studies revealed the existence of a higher density of Sn and S vacancies for the 2% SnS:Tb. Finally, the photosensing studies revealed higher R, EQE, and D* values of 1.90 × 10⁻¹ AW⁻¹, 44%, and 3.46 × 10⁹ Jones for the SnS:Tb 2%, respectively. In contrast to the other fabricated photodetectors, SnS:Tb 2% thin films exhibit a faster 0.33 s rise and 0.69 s fall duration, which would be more appropriate for photodetector applications.