Synthesis of tungsten diselenide nanoparticles by chemical vapor condensation method

Abstract

Crystalline tungsten diselenide (WSe2) nanoparticles have been synthesized by a gas phase reaction using tungsten hexacarbonyl and elemental selenium as precursor. The WSe2 nanoparticle morphology varies from the spherical shape to flake-like layered structures. Usually particles consist of 5 – 7 single layers of WS2. Mean size in smaller dimension are less than 5 nm and the number of layers decreased linearly with decreasing reaction time and concentration of carbonyl in the gas phase. The mean value of interlayer distance in <0001> direction is comparable with the microscopic values. The selenium-to-tungsten atomic ratios in the interval of 2.07 …2.19 were determined, approach to the stoichiometric ratio of 2:1. Main impurities are oxygen and carbon and strongly interrelated with carbonyl concentration in the gas phase.