Tunable contacts and device performances in graphene/group-III monochalcogenides MX (M = In, Ga; X = S, Se) van der Waals heterostructures

Graphene-based van der Waals (vdW) heterostructures have attracted extensive attention for applications like nanoelectronics. The graphene and group-III monochalcogenide (MX, M = In and Ga and X = S and Se) heterostructures were established herein, and the electronic properties were investigated by the first-principles calculation. These heterostructures form an n-type Schottky contact at the interface and the Schottky barrier height can be modulated by the external strain. With graphene as electrodes, the device performances of the 9 nm MX metal-oxide-semiconductor FETs (MOSFETs) are investigated. Based on the computed tunneling probability and transfer characteristics, the GaSe MOSFET with a graphene electrode stands out with the highest tunneling probability and largest on-off ratio. We believe these results can provide physical insights into designing and fabricating devices based on the graphene and group-III monochalcogenide heterostructures.