Vertical and Bidirectional Heterostructures from Graphyne and MSe2 (M = Mo, W)

Abstract

Vertical and lateral heterostructures with atomically clean and sharp interfaces have opened up new realms in materials science, device physics and engineering. Herein, inspired by recent experiments, the unprecedented bidirectional heterostructures (BDHs) of γ-graphyne@MoSe2/WSe2 as well as γ-graphyne@MoSe2 and γ-graphyne@WSe2 are proposed and examined on the basis of first-principles calculations. Our results reveal that a novel wrinkled γ-graphyne with narrowed energy gap and strong binding strength is achieved on the planar and smooth substrate in γ-graphyne@MoSe2/WSe2. The direct-indirect band gap crossover is also found in terms of interlayer coupling. Furthermore, we demonstrate that electron-hole pairs can be spatially separated, and the carrier mobility would be benefited from the absorbed γ-graphyne in the BDHs. These results provide not only new insights into the physical and chemical properties of the vertical and bidirectional heterostructures, but also a new strategy for fabricating unprecedented 2D nanomaterials with exciting properties.