Synthesis, characterization and electrostatic properties of WS2 nanostructures

We report the direct growth of atomically thin WS2 nanoplates and nanofilms on the SiO2/Si (300 nm) substrate by vapor phase deposition method without any catalyst. The WS2 nanostructures were systematically characterized by optical microscopy, scanning electron microscopy, Raman microscopy and atomic force microscopy. We found that growth time and growth temperature play important roles in the morphology of WS2 nanostructures. Moreover, by using Kelvin probe force microscopy, we found that the WS2 nanoplates exhibit uniform surface and charge distributions less than 10 mV fluctuations. Our results may apply to the study of other transition metal dichalcogenides by vapor phase deposition method