Controllable synthesis of NiS and NiS2 nanoplates by chemical vapor deposition

Mulitipe stoichiometric ratio of two-dimensional (2D) transition metal dichalcogenides (TMDCs) attracted considerable interest for their unique chemical and physical properties. Here we developed a chemical vapor deposition (CVD) method to controllably synthesize ultrathin NiS and NiS2 nanoplates. By tuning the growth temperature and the amounts of the sulfur powder, 2D nonlayered NiS and NiS2 nanoplates can be selectively prepared with the thickness of 2.0 and 7.0 nm, respectively. X-ray diffraction (XRD) and transmission electron microscopy (TEM) characterization reveal that the 2D NiS and NiS2 nanoplates are high-quality single crystals in the hexagonal and cubic phase, respectively. Electrical transport studies show that electrical conductivities of the 2D NiS and NiS2 nanoplates are as high as 4.6 x 10(5) and 6.3 x 10(5) S.m(-1), respectively. The electrical results demonstrate that the synthesized metallic NiS and NiS2 could serve as good electrodes in 2D electronics.