Large-area growth of high-quality transition metal dichalcogenides for optoelectronics and electronics

Abstract

The electronic and optoelectronic properties of 2D materials and their stacking heterostructures have inspired enormous interests. WSe2, as a p-type semiconductor, represents a foremost building block in the p-n junctions. WSe2 shall possesses the features of large area, homogeneity, and precise layer control. To date, there is yet an ideal synthesis method ever reported. First, we present a facile approach to prepare high-quality wafer-scale homogenous WSe2 full films. In brief, we first deposit a thin layer of metal and then do the selenization. We can control the film thickness of WSe2 in a chemical equilibrium environment. Second, we present a facile approach to prepare high-quality large-area homogenous WSe2 full films. In brief, we developed a pre-seeding strategy for depositing W-containing precursors over dielectric substrates, which form well-distributed particles as seeding center. Upon the salt-assisted sublimation of tungsten oxides, the WSe2 forms over the seeded substrates (at high temperature) in the Se-rich atmosphere. Eventually the high quality of the synthetic film has been reflected on the high performances of photodetectors and field-effect transistors. Our finding may pave the way of wafer scale integration of transition metal dichalcogenides in the integrated flexible electronics.