▎ 摘　　要

We report the results of a thorough numerical study on carrier mobility in graphene nanoribbons (GNRs) with the widths from similar to 250 nm down to similar to 1 nm, with a focus on the influence of substrate type (SiO2, Al2O3, HfO2, and h-BN) and substrate quality (different interface impurity densities) on GNR mobility. We identify the interplay between the contributions of Coulomb and surface optical phonon scattering as the crucial factor that determines the optimum substrate in terms of carrier mobility. In the case of high impurity density (similar to 10(13) cm(-2)), we find that HfO2 is the optimum substrate irrespective of GNR width. In contrast, for low impurity density (10(10) cm(-2)), h-BN offers the greatest enhancement, except for nanoribbons wider than similar to 200 nm for which the mobility is highest on HfO2. (C) 2013 AIP Publishing LLC.