CVD-grown 2D molybdenum diselenide: Morphology, spectroscopic and mechanical characterization

Two dimensional MoSe2 mono and few layer were prepared by the atmospheric pressure chemical vapor deposition (CVD). It is essential to understand completely the growth and nucleation mechanism to improve the crystalline quality and size of two dimensional transition metal dichalcogenides materials using CVD. Three different types of MoSe2 surface structure were identified for the different growth temperatures. By changing the growth temperatures, the concentration of MoO3-x and Se vapor precursors vary which derive different nucleation mechanism. Low vapor concentration of reactants leads to mono and bi layer MoSe2 due to 2D planar nucleation while higher concentration of reactants facilitates the self-seeding role that leads to few and multilayers MoSe2. The presence of the defects in monolayer was confirmed by photoluminescence spectra analysis. The surface friction of the mono and few layers were studied experimentally using the lateral force microscopy. The surface friction of MoSe2 depends on the number of layers presents in the surface flakes. (C) 2019 Elsevier B.V. All rights reserved.