Monolayer graphene/hexagonal boron nitride heterostructure

A buried metal-gate field-effect transistor (FET) using a stacked hexagonal boron nitride (h-BN) and chemically vapor deposited (CVD) graphene heterostructure is demonstrated. A thin h-BN multilayer serves as both gate dielectric and supporting layer for the monolayer graphene channel. It is observed that electrical stressing could significantly improve graphene conduction, similar to the effect reported in the graphene/SiO2 system. In the graphene/h-BN/TiN FET structure, p-type doping behavior in graphene is observed, possibly attributed to spontaneous doping due to the work function difference between the graphene channel and the metal gate electrode. At a high-level of stress, graphene exhibits n-type doping behavior due to charge transfer across the thin h-BN multilayer. The dielectric strength and tunneling behavior of h-BN are investigated, showing the robust nature of the layer-structured insulator.