Modeling the velocity saturation region of graphene nanoribbon transistor

A semi-analytical model for impact ionisation coefficient of graphene nanoribbon (GNR) is presented. The model is derived by calculating the probability of electrons reaching ionisation threshold energy E_t and the distance travelled by electron gaining E_t. In addition, ionisation threshold energy is semi-analytically modeled for GNR. We justify our assumptions using analytical modeling and comparison with simulation results. Gaussian simulator together with analytical modeling is used in order to calculate ionisation threshold energy and Kinetic Monte Carlo is employed to calculate ionisation coefficient and verify the analytical results. Finally, the ionization profile is presented using the proposed models and simulation is carried out. The results are compared with that of silicon.