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We have carried out the electrical and optical characterization of thin films of compounds based on Sn-S bonds (SnS 2 , Sn 2 S 3 ), prepared by plasma-enhanced chemical vapour deposition (PECVD), as a function of the relative concentration of the precursor vapours, SnCl 4 and H 2 S, keeping all other deposition parameters constant. In all studied cases, the deposited films were formed by polycrystalline materials. The optical bandgap values of deposited materials were calculated from optical transmittance and reflectance measurements. The SnS 2 compound produced under certain deposition conditions has a forbidden bandgap around 2.2 eV. This compound shows n-type electrical conductivity, whose dark value at room temperature is 2 ×10 −2 ( cm) −1 . Also, it shows the typical semiconductor dependence of its electrical conductivity on the temperature with an activation energy of about 0.15 eV. However, thin films of a mixture of SnS 2 and Sn 2 S 3 compounds were deposited with higher values of the relative concentration of source vapours than those used to obtain the SnS 2 compound. The optical bandgap shows a decreasing trend as the relative concentration increases. A similar trend is observed for dark electrical conductivity. These results create the opportunity to use Sn X S Y compounds in thin films for building heterojunction solar cells prepared completely by PECVD.

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