Graphene nanoribbon tunneling field effect transistors

The electron-hole symmetry characteristic of graphene nanoribbons (GNRs) gives rise to the electron (hole) tunneling through valence (conduction) band states. By employing this property we have numerically investigated GNR field effect transistors with p+-type source and drain in the presence of a gate voltage-induced n-type channel using the non-equilibrium Green's function formalism.For long channels, the traditional FET-like I-V behavior is achieved, but at short channels, the sub threshold current opens up an oscillatory dependence on the gate voltage with a considerable amount of current of over 10−6 A. This is the characteristic current behavior of resonant tunneling transistors that exhibit regions of negative differential resistance. The calculated discrete density of states in the channel attributes this behavior to the constructed n-type channel island between p-type source and drain with thin barriers formed by the energy gap.

► Graphene nanoribbon FETs of p-type source and drain and n-type channel is studied.
► The non-equilibrium Green's function formalism is employed.
► Long channel gathers FET-like I–V behavior by the electron-hole symmetry of graphene
► At short channels, the current oscillates with the gate voltage.
► The current oscillation is the characteristics of the resonant tunneling devices.