Effect of edge roughness in graphene nanoribbon transistors

The effects of edge irregularity and mixed-edge shapes on the characteristics of graphene nanoribbon transistors are examined by self-consistent atomistic simulations based on the nonequilibrium Green's function formalism. The minimal leakage current increases due to the localized states induced in the band gap, and the on current decreases due to smaller quantum transmission and the self-consistent electrostatic effect in general. Although the ratio between the on current and minimal leakage current decreases, the transistor still switches even in the presence of edge roughness. The variation between devices, however, can be large, especially for a short channel length. (C) 2007 American Institute of Physics.