Effects of an edge vacancy on electron transport in zigzag-graphene nanoribbons with oxygen terminations

Producing graphene nanoribbons (GNRs) by the unzipping method is a promising way to mass produce GNRs, paving the way for their widespread use in electronic devices. However, the effects of edge defects on their electronic states and electron transport remain poorly understood. We theoretically investigated electron transport in oxygen-terminated zigzag GNRs (O-ZGNRs) with a single edge vacancy by ab initio calculations based on the density functional theory combined with the non-equilibrium Green's function technique. We found that in an energy range wherein the electronic states of O-ZGNRs are strongly localized at the edge oxygen atoms, electrons are strongly scattered by the edge vacancy. In contrast, in other energy ranges, the electron density lies inside the ribbon, not at the edge. Thus, the edge vacancy has little influence on the transport characteristics of O-ZGNRs in these energy ranges, and eventually, the transport characteristics are almost independent of the ribbon width.