Optical and Structural Studies on SnS Films Grown by Co-Evaporation

Polycrystalline SnS thin films were grown on glass substrates using a novel procedure involving a chemical reaction between the precursor species evaporated simultaneously. This is a relatively new material, which exhibits excellent properties to be used as absorbent layer in solar cells. X-ray diffraction (XRD) measurements indicate that the synthesized samples grow in several phases (SnS, SnS2 and Sn2S3) depending upon the deposition conditions. However, through an exhaustive parameter study, conditions were found to grow thin films predominantly in the SnS phase with orthorhombic structure. It was found that this type of compound presents p-type conductivity, a high absorption coefficient (greater than 104 cm−1) and an energy band gap Eg of about 1.3 eV, indicating that this compound has good properties to perform as absorbent layer in thin film solar cells.