Effect of annealing on structural and optical properties of SnS2 thin films grown by thermal evaporation and post sulphur annealing technique

Abstract Recently, two-dimensional layered semiconductors caught attention due to their tuneable thickness dependent properties and its optoelectronic device applications. This paper reports the effect of annealing temperature and annealing duration on structural, compositional and optical properties of tin disulphide thin films (SnS2) fabricated using a bi- stage process. The process involves thermal evaporation of metallic tin precursor films and post sulphur annealing process in a non-vacuum furnace. The annealing temperatures ranged from 300 °C to 500 °C while annealing time varied from 0.5 to 3 hours. The annealing at 300°C improved the crystallinity of SnS2 thin films. Raman analysis showed a prominent peak at 207 cm−1, while at higher temperatures nanocrystalline SnS2 phase is observed. Optical bandgap got reduced as annealing temperature increased and at 300°C, the bandgap was 2.7 eV. The above obtained properties of SnS2 opens a pathway for using these films for potential applications.