Effect of Ribbon Width and Doping Concentration on Device Performance of Graphene Nanoribbon Tunneling Field-Effect Transistors

The device performance of graphene nanoribbon (GNR) tunneling field-effect transistor (TFET) is studied using the self-consistent non-equilibrium Green's function (NEGF) and quasi-two dimensional Poisson solver based on the Dirac equation model. The effects of different GNR widths and doping concentrations at the source and drain on the device characteristics are investigated and the electronic property of the GNR TFET is found to be strongly dependent on its width. A comprehensive characterization of this dependence is expected to be crucial to the designs and fabrications of GNR TFETs. Furthermore, the doping concentrations at the source and drain is found to play a crucial role on the ON-and OFF-state currents (I-ON and I-OFF) respectively. Therefore, the ability to control the doping concentrations allows the tailoring of the drive current, the I-ON=I-OFF ratio and the subthreshold swing of GNR TFETs to meet different design requirements. (C) 2010 The Japan Society of Applied Physics