A new approach to thin-film SnS PV using MOCVD

Abstract

SnS thin films were deposited by an inline metal organic chemical vapour deposition process using tetramethyltin and diethyldisulfide as precursors. A N2/H2 carrier was used with pre-mixing of the precursors before overhead injection into the deposition chamber. NSG AB soda lime glass was used as the substrate with area of 50 × 50 mm2. The resulting SnS films had calculated band gaps between 1.3 and 1.5 eV. Scanning electron microscopy showed relatively large grains ranging from 0.5 to 1 μm across for a SnS film sample deposited at 556–558 °C. X-ray diffraction confirmed the films to be SnS, but with small concentrations of impure phases such as Sn2S3. Post-growth annealing treatment in a N2 atmosphere at 435 °C using SnCl2/MeOH solution at different molar concentrations only showed changes to the film at 0.05 M. The 0.05 M SnCl2/MeOH treatment was aggressive with blistering and etching occurring.