The effects of vacancies on the transport properties of zigzag graphene nanoribbons

The transport properties of zigzag graphene nanoribbons (ZGNRs) with different patterns of vacancies are investigated by using density functional theory and nonequilibrium Green's function (NEGF) formalism. It is found that the transport properties are different with a different lattice type vacancy (A-type or B-type vacancy). The conductance of ZGNRs is more sensitive to an interior vacancy than an edge vacancy. More importantly, the pattern of interior vacancies has enormous influence on the electron transport around the Femi energy. As hexagon carbons are removed, the ZGNRs transform from metallic to semiconducting. Thus one can tune the electron properties of ZGNRs by patterning vacancies.