Vapor pressure-controllable molecular inorganic precursors for growth of monolayer WS2: Influence of precursor-substrate interaction on growth thermodynamics

Abstract

A chemical route for the growth of centimeter-scale and homogeneous WS2 monolayer has been developed using the penta-coordinated inorganic W complex, WOCl4. The relatively low melting point of WOCl(4 )compared to other conventional W precursors enables the use of WOCl4 & nbsp;as a vapor phase precursor. Consequently, the precise control of partial pressure during chemical vapor deposition (CVD) allows the optimization of growth conditions, synthesizing the entirely covered homogeneous monolayer WS(2 & nbsp;)film. The contamination of amorphous carbon, which is considered a demerit of metal-organic CVD, is highly reduced because of the carbon-free compositional characteristic of WOCl4. Additionally, the growth behavior of WS2 & nbsp;with respect to the growth parameters is systematically studied by investigating the thermodynamics of the molecular precursors compared with MoS2 & nbsp;growth using MoOCl4. This approach enables us to understand the effect of the growth temperature and partial pressure on the optimum growth conditions of WS2 monolayer.