  A tunneling field effect transistor based on armchair graphene nanoribbons is
studied using ballistic quantum transport simulation based on 3D real space
nonequilibrium Green's function formalism. By introducing a pocket doping
region near the source, the performance of GNRs TFET is improved in terms of
larger on current and steeper subthreshold swings compared to conventional
tunneling FET. It is also found that pocket region introduces two interesting
features. By increasing the pocket length the ambipolar can be effectively
suppressed. Furthermore, there is negative trans-conductance at negative gate
voltage due to resonance.
