Transport behaviors of graphene 2D field-effect transistors on boron nitride substrate

We present a numerical study of the transport behavior of a top-gate 2D-graphene field-effect transistor with boron nitride as substrate and gate insulator material. It is based on a non-equilibrium Green´s function approach to solving a tight-binding Hamiltonian of graphene, self-consistently coupled with 2D-Poisson´s equation. The analysis emphasizes the effects of the chiral character of carriers in graphene in the different conduction regimes, including Klein and band-to-band tunneling processes. We investigate the effects of gate length and gate insulator thickness, and the possible effect of BN-induced bandgap opening on the device characteristics, in particular in terms of on/off ratio, short-channel effect and saturation behavior, found to be in good agreement with experimental results. Additionally, the possibility of current oscillations and negative differential conductance typical of GFET is demonstrated.