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-non-equilibrium Green´s functionstate currents (I_OFF), the ON-state currents (I_ON) and the subthreshold slope (SS) significantly while variation in drain doping changes mainly the I_OFF. Additionally, low SS and large I_ON/I_OFF ratio can be achieved by applying proper asymmetric source-drain doping.