Source/drain doping influence on heterojunction graphene nanoribbon tunneling field effect transistors

We investigate the device performance of heterojunction graphene nanoribbons tunneling field-effect transistors as a function of the doping concentrations based on the non-equilibrium Green's function. We observe that variation in source doping changes the OFF-state currents (IOFF), the ON-state currents (ION) and the subthreshold slope (SS) significantly while variation in drain doping changes mainly the IOFF. Additionally, low SS and large ION/IOFF ratio can be achieved by applying proper asymmetric source-drain doping.