Physical Properties of Nano-crystalline SnS2 Layers Grown by Chemical Bath Deposition

Tin disulphide (SnS2) nano-crystalline films were deposited on glass substrates by chemical bath deposition using tin chloride (SnCl2) and thioacetimide (C2H5NS) as the precursors with triethanolamine and ammonia (NH4) as the complexing agents at a bath temperature of 60oC. The layers were grown by varying the volume of ammonia added to the reaction bath. The crystal phases present and structure of the as-grown films were evaluated using X-ray diffraction (XRD), surface topography using scanning electron microscope (SEM), composition of the elements present using energy dispersive X-ray analysis (EDAX), absorption coefficient and energy band gap using UV-Vis-NIR spectrophotometer. The grown layers had compositional deviation from stoichiometry. The layers showed (001) plane as the preferred orientation and the surface topography revealed warm-like grains that were uniformly distributed over the substrate surface. The optical transmittance of the films was > 80% and a clear blue shift in the absorption edge was observed due to quantum confinement with the evaluated energy band gap changing from 3.3 eV to 3.7 eV with the decrease of ammonia content present in the reaction bath. The details of these results are presented and discussed.