  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 non-equilibrium 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.
