Step-edge controlled fast growth of wafer-scale MoSe2 films by MOCVD

Abstract

Two-dimensional (2D) transition metal dichalcogenides (TMDCs), due to their unique physical properties, have a wide range of applications in the next generation of electronics, optoelectronics, and valleytronics. Large-scale preparation of high-quality TMDCs films is critical to realize these potential applications. Here we report a study on metal-organic chemical vapor deposition (MOCVD) growth of wafer-scale MoSe2 films guided by the crystalline step edges of miscut sapphire wafers. We established that the nucleation density and growth rate of MoSe2 films were positively correlated with the step-edge density and negatively with the growth temperature. At a certain temperature, the MoSe2 domains on the substrate with high step-edge density grow faster than that with low density. As a result, wafer-scale and continuous MoSe2 films can be formed in a short duration (30 min). The MoSe2 films are of high crystalline quality, as confirmed by systematic Raman and photoluminescence (PL) measurements. The results provide an important methodology for the rapid growth of wafer-scale TMDCs, which may promote the application of 2D semiconductors.