Nano-flower and nano-wall SnS2 films fabricated with controllable shape and size by the PECVD method

In the present work, SnS2 films are deposited from solid source materials of S, Na2S2O3 ⋅ 5H2O and SnCl4 ⋅ 5H2O by the plasma-enhanced chemical vapor deposition (PECVD) method. Through controlling the deposition parameters, SnS2 films with nano-flower and nano-wall structure can be deposited without using any additives. By changing the deposition parameters, such as the molar ratio of S/Sn in source material, deposition temperature and the different kinds of sulfur source materials, SnS2 films with different morphology, building block and chemical composition can be produced. Furthermore, the formation mechanisms of the obtained morphologies have also been studied. It is mainly based on the crystal growth habit and the influence of the concentration of the sulfur radical in the vicinity of the growing surface. Moreover, the optical properties of SnS2 films have also been discussed. Due to the small size of SnS2 nanostructures, optical band gaps display the significant blue shift. (paper)