A Computational Study on the Electronic Transport Properties of Ultranarrow Disordered Zigzag Graphene Nanoribbons

In this paper, the effect of structural nonidealities on the electronic transport properties of ultranarrow zigzag graphene nanoribbons (ZGNRs) is systemically investigated for the first time, employing the nonorthogonal third nearest neighbor mean-field Hubbard model along with the nonequilibrium Green's function formalism. We have evaluated the influence of line-edge roughness, single atom vacancies, and substrate-induced potential fluctuations on the transport gap, ON- and OFF-state conductances, and the ON/OFF conductance ratio of 12-nm-length ultranarrow ZGNRs. The results reveal that while even moderate amounts of edge roughness lead to a nonuniform suppression of the transmission probability and increase the transport gap, the presence of single atom vacancies tends to decrease the induced transport gap. Furthermore, it is shown that the transport properties of ZGNRs are more robust against potential fluctuations compared with their armchair counterparts.