Deposition and Characterization of Antimony Tin Sulphide using Spray Pyrolysis

Spray pyrolysis is a method commonly used in aerosol processes for atomizing chemical precursors into aerosol droplets ready for dispersion in gas mediums to form thin films on passing through a hot reactor and getting evaporated. In this study, antimony tin sulphide was synthesized using spray pyrolysis, as it is a simpler and economical technique. Doping with antimony (Sb) showed a persistent decrease in band gap with an increase in Sb. Results showed that doping tin sulphide (SnS) with Sb enhanced the absorption spectrum of the SnS film by widening the absorption peaks of SnS (Sb) films, and consequently broadening the absorption band. The absorption spectrum of SnS film was extended from 424 nm (ultraviolet edge) to 493 nm, 517 nm, 516 nm and 512 nm (visible regions), respectively. This shows that Sb serves as an opaque material in the SnS (Sb) films, which absorb light more than transparent materials. Detailed information about the optical band gap was obtained using the dependence of the absorption coefficient on the photon energy. The bandgap was varied between 3.33 and 1.90 eV. Further results on antimony tin sulphide films at different annealing temperatures are presented. X-ray diffraction (XRD) showed a preferential peak of the plane (1 1 1) at 2θ = 31.69, which was predominantly persistent in all the synthesized films. Scanning Electron Microscope (SEM), which showed the surface morphology of the synthesized SnS and SnS(Sb), indicates that the formed films were non-uniformly sparsely distributed grains, thus, depicting high-quality crystal films.