Intrinsic electronic and transport properties of graphene nanoribbons with different widths

The intrinsic electronic and transport properties of a series of zigzag graphene nanoribbons (ZGNRs) have been investigated systematically using density functional theory coupled with the non-equilibrium Green's function (NEGF) method. It is found that ZGNRs with various ribbon widths have completely different transport properties under bias, depending on whether the number of zigzag chains is odd or even. ZGNRs with odd number except 1-ZGNR possess small current regardless of the bias applied. In contrast, ZGNRs with even number have much larger current and behave as a resistor having a linear current-voltage relationship. The results also reveal that the narrow ZGNRs, e.g., 1-ZGNR and 2-ZGNR, have different transport behaviors, which are governed by the edge-effect and the unique electronic structure.