Morphologies and optical properties of mixed tin oxysulfide produced by evaporation condensation of SnS

The goal of the present study was to use the evaporation-condensation method of SnS to synthesize mixed novel tin oxysulfide nanostructures. Structural, morphological and optical properties of these nanomaterials were investigated. Synthesis was carried out in horizontal tube furnace using Au coated quartz and Si(100) substrates. The substrates were set along 1-25 cm from the centered alumina boat. The deposition was observed mainly in two regions. Region A was close to the boat and extended approximately 6 cm from it and region B started approximately 15 cm from the center of the boat and extended over 10 cm towards the end of the tube. EDAX and XRD analysis revealed formation of mixed tetragonal SnO2 and tetragonal tin oxide sulfate, SnO2SO4, in region A whereas mixed orthorhombic SnS and tetragonal tin oxide sulfate in region B. SEM investigations showed randomly oriented nanowires and cotton candy morphologies for samples prepared in regions A and B, respectively. Moderate transmittance, high refractive index (2.218 at 550 nm) and two optical band gaps of 1.87 eV and 3.35 eV were obtained for samples prepared in region A whereas high transmittance, moderate refractive index and optical band gap of 1.82 eV were obtained for the samples prepared in region B. The obtained results, especially the new oxysulfide samples, may have find applications in various fields.