Dual-gated mono–bilayer graphene junctions

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.