structural and optoelectrical properties of single phase sns2thin films at various substrate temperatures by spray pyrolysis

Thin films of sns2 were prepared, as the absorber layer in solar cells, using an aqueous solution of sncl4 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 sns2 along (001) in all layers; there was no sign of other unwanted phases. with increasing of substrate temperature from 325 to 400 °c, 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 40% in the visible region and the band gap reduced from 2.8 to 2.55 ev with increment in temperature from 350 to 400 °c. photoluminescence spectra of the prepared film, which was formed at 400 °c showed a dominant peak at 530 nm, caused by recombination of excitons. the least electrical resistivity of the sns2 thin film prepared at 400 °c in dark and light environment were 4.6 x10^-3 ωcm and 0.65*10^-3 ωcm, respectively; which demonstrated 400 °c was the optimum temperature in point of optoelectrical properties in the sns2 thin film.