Engineering the crystallinity of tin disulfide deposited at low temperatures

Tin disulfide (SnS 2 ), which exhibits a two-dimensional (2D) layered structure, is considered to be a promising channel material for thin film transistors because of its high electrical performance and low temperature processibility. In this work, we deposited crystalline SnS 2 at 150 °C using atomic layer deposition (ALD) which is compatible with current electronic device processing methods. And then, crystalline SnS 2 films were annealed to investigate the change in crystallinity. We carried out sulfur annealing of the SnS 2 films at temperatures of 250, 300 and 350 °C. The effects of sulfur annealing were investigated in a mixed gas atmosphere of 100 sccm argon (Ar) and 5 sccm hydrogen (H 2 ). SnS 2 samples were examined using XRD, TEM, XPS, UV-vis and PL. The crystallinity of the SnS 2 films after annealing was improved, and its grain size became larger compared with the as-deposited SnS 2 film. We also observed a clear two dimensional layered structure of SnS 2 using high resolution TEM. The change in the optical properties of the SnS 2 films was observed using UV-vis and PL. We report here that SnS 2 films deposited at 150 °C and annealed at below 350 °C have good potential for using 2D SnS 2 in flexible electronic devices.