Influence of contact doping on graphene nanoribbon heterojunction tunneling field effect transistors

We investigated the device performance of graphene nanoribbon tunneling field-effect transistors with heterogeneous channel as a function of the contact doping concentrations. The simulations were carried out based on the non-equilibrium Green’s function, coupled with a Dirac Hamiltonian model, and the roles of symmetric and asymmetric contact doping concentrations on the device performance were identified. It was observed that the device performances such as OFF-state currents (IOFF), ON-state currents (ION) and subthreshold slopes (SSs) were greatly influenced by the source doping concentrations, while variations in drain doping concentrations changed mainly the IOFF. By applying proper asymmetric source and drain doping concentrations, low SS and large ION/IOFF ratio can be achieved, indicating that it is an alternative route to effectively enhance the device performance.

► Doping concentration effect on the changes of ON/OFF-states currents.
► ION is increased by increasing the source doping concentration.
► IOFF is decreased by decreasing the drain doping concentration.
► Device performance can be optimized by changing doping concentration.