▎ 摘　　要

Two kinds of junctions based on doped graphene nanoribbons (GNRs) are designed and studied in this article. One is the N-doped armchair GNR (AGNR) joined directly by B-doped AGNRs, and another is similar, but there is an undoped AGNR between them. The transport properties are calculated using the full self-consistent ab initio nonequilibrium Green's function and density-functional theory methods under external bias. We find that the I-V curves for both junctions have a striking nonlinear feature and show large negative differential resistance properties, not only at the positive bias but also at the negative one. The results also indicate that the diode-like properties are kept and the rectification coefficient is very high within a wide bias region. Our calculations reveal that the formation of these peculiar transport behaviors is due to the great changes of the transmission spectra and the projected self-consistent Hamiltonian eigenvalues with the applied bias voltage. These findings suggest that the doped AGNRs may offer unique opportunities for the future development of nanoscale electronics. (C) 2011 American Institute of Physics. [doi:10.1063/1.3605489]