Dual-gated mono–bilayer graphene junctions

Abstract

A lateral junction with an atomically sharp interface is extensively studied in fundamental research and plays a key role in the development of electronics, photonics and optoelectronics. Here, we demonstrate an electrically tunable lateral junction at atomically sharp interfaces between dual-gated mono- and bilayer graphene. The transport properties of the mono–bilayer graphene interface are systematically investigated with I_ds–V_ds curves and transfer curves, which are measured with bias voltage V_ds applied in opposite directions across the asymmetric mono–bilayer interface. Nearly 30% difference between the output I_ds–V_ds curves of graphene channels measured at opposite V_ds directions is observed. Furthermore, the measured transfer curves confirm that the conductance difference of graphene channels greatly depends on the doping level, which is determined by dual-gating. The V_ds direction dependent conductance difference indicates the existence of a gate tunable junction in the mono–bilayer graphene channel, due to different band structures of monolayer graphene with zero bandgap and bilayer graphene with a bandgap opened by dual-gating. Simulation of the I_ds–V_ds curves based on a new numerical model validates the gate tunable junction at the mono–bilayer graphene interface from another point of view. The dual-gated mono–bilayer graphene junction and new protocol for I_ds–V_ds curve simulation pave a possible way for functional applications of graphene in next-generation electronics.