▎ 摘　　要

When it comes to extremely downscaled graphene device research, it is imperative to develop a comprehensive understanding of what kinds of edge irregularities are likely to occur in the realistic graphene nanoribbons (GNRs) as well as their impact on the electronic and transport properties of GNRs. Here we present the first-principle calculations of the formation energy of the edge vacancies and protrusions in the armchair GNRs (AGNRs) with widths ranging from 9 to 12 carbon atoms and zigzag GNRs (ZGNRs). We also examine their influence on the electronic states and transport characteristics of the GNRs. The formation energy calculations show that double vacancy (DV) edge defects and zigzag protrusions are the most likely edge irregularities in the AGNRs. The DV edge defects increase the bandgap in 11-AGNRs and decrease the bandgap in 9, 10, 12-AGNRs. Zigzag protrusions widen the bandgap in 9, 12-AGNRs and reduce the bandgap in 10, 11-AGNRs. Edge defects induced wave function localization leads to the anti-resonant transmission characteristics. Edges of the ZGNRs show a high tendency to be modified by the exothermic effect. However, their current carrying capacity is not compromised by the edge irregularities.