▎ 摘　　要

The electronic and transport properties of the Z-shaped graphene nanoribbons heterojunction are investigated by a fully self-consistent non-equilibrium Green's function method combined with density functional theory. The first-principles calculations show that the robust quantum confinement effect in the junction can be used to design the quantum dot. The electronic states are confined by the topological structure of the junction. This kind of Z-shaped quantum dot can be realized regardless of doping impurity, edge chemical modification, and the length of junction. Moreover, the spatial distribution and the number of confined states are tunable.