A Numerical Study of Line-Edge Roughness Scattering in Graphene Nanoribbons

The role of line-edge roughness scattering on the electronic properties of graphene nanoribbons is numerically investigated. The nonequilibrium Green function formalism, along with an atomistic tight-binding model, is employed. Our results indicate that, depending on the geometrical and roughness parameters, the transport of carriers can be in the diffusive or localization regime. We extract the mean free path and the localization length, which characterize the diffusive and localization regimes, respectively. In the diffusive regime, the conductance linearly decreases with length, whereas in the localization regime, it exponentially decreases with length. However, as the localization length depends on the carrier energy, an effective transport gap in this regime can be defined. This gap is evaluated as a function of the geometrical and roughness parameters, and its impact on the device performance is discussed.