Vertical heterostructure field effect transistor for high performance electronics

Graphene has emerged as an exciting material for future electronics and optoelectronics due to its unique electrical, optical and mechanical properties. However, the lack of an intrinsic bandgap in graphene has limited the achievable on-off ratio in transistors using graphene as an active channel. The creation of a transport gap in graphene nanostructures or bilayer graphene can improve the on-off ratio, but often at a severe sacrifice of the deliverable current density. With single atomic thickness, finite density of states and weak screening effect, graphene exhibits a field-tunable work-function and partial electrostatic transparency. It can thus function as an active contact in tunable graphene-semiconductor junction to enable a new generation of vertical device^1-5. Here we discuss three different vertical field-effect transistors, which have been recently demonstrated with greatly improved on-off ratio and current density, as well as unique properties such high flexibility, stability and low cost. This could open up a new pathway to graphene electronics and ultra-flexible thin film transistors.