▎ 摘　　要

The electrical conductance of zigzag graphene nanoribbons (ZGNRs) is numerically investigated in the presence of different percentages of edge and middle vacancies. The vacancies are randomly distributed in the edge or innermost of ZGNRs. We take advantage of recursive Green's function under tight-binding model to study the electrical conductance. It is found that in the both vacancy types, and all widths and lengths of our samples, the conductance degrades as the vacancy concentration increases. In addition, we illustrate how transport properties are sensitive to the width and length of nanoribbon. At fixed defect concentration, the length growth leads to exponential decrease, and the width growth leads to power law increase in the conductance of ZGNRs, respectively. Under the same numerical framework, we have also studied transition from metal to insulator and vice versa. (C) 2015 Elsevier B.V. All rights reserved.