▎ 摘　　要

We present a theoretical study of current-voltage characteristics of different junctions of graphene nanoribbons. We considered isolated Y- and T-junctions of graphene nanoribbons (GNRs) with various geometry parameters and a graphene Y-junction in the graphane sheet. Our ab initio calculations based on the nonequilibrium Green's functions formalism displayed the influence of the geometry parameters of different ribbons on the I-V curves e.g. the shifting of zero voltage regions. We showed that not only the shape of the structure, but also the arrangement of electrodes attached to the structure will lead to changes in the transport properties.