Structural and Optoelectrical Properties of Single Phase SnS۲ Thin Films at Various Substrate Temperatures by Spray Pyrolysis

Thin films of SnS۲ were prepared, as the absorber layer in solar cells, using an aqueous solution of SnCl۴ and thiourea by spray pyrolysis technique. Effect of the Substrate temperature on the properties of these thin films was studied. Investigation via XRD showed the formation of polycrystalline SnS۲ along (۰۰۱) in all layers; there was no sign of other unwanted phases. With increasing of substrate temperature from ۳۲۵ to ۴۰۰ ۰C, the crystallinity of the sample was improved, after that, it deteriorated the crystallinity. Layers had granular morphology and Valley- Hills topography. UV-VIS spectra revealed that the transmittance of all layers was lower than ۴۰% in the visible region and the band gap reduced from ۲.۸ to ۲.۵۵ eV with increment in temperature from ۳۵۰ to ۴۰۰ ۰C. Photoluminescence spectra of the prepared film, which was formed at ۴۰۰ ۰C showed a dominant peak at ۵۳۰ nm, caused recombination of excitons. The least electrical resistivity of the SnS۲ thin film prepared at ۴۰۰ ۰C in dark and light environment were ۴.۶ ×۱۰ -۳ Ωcm and ۰.۶۵×۱۰ -۳ Ωcm, respectively; which demonstrated ۴۰۰ ۰C was the optimum temperature in point of optoelectrical properties in the SnS۲ thin film.

Keywords:

Spray pyrolysis , Chalcogenide , Thin films , Tin disulfide