Bipolar spin-filtering effect in B- or N-doped zigzag graphene nanoribbons with asymmetric edge hydrogenation

•We have investigated the spin-dependent transport properties of the H2–5(6)ZGNR–H devices with B/N doping in both ZGNR electrodes.•A perfect bipolar spin-filtering effect can be obtained in 5(6)ZGNR-based hetero-structures with P and AP magnetic configurations.•The graphene-based diode can be attained by manipulating the doping positions of B or N atoms in both electrodes.

The spin transport properties of zigzag graphene nanoribbon (ZGNR) hetero-junctions, in which ZGNR electrodes are doped with B or N atoms, are investigated based on spin-polarized density functional theory and non-equilibrium Green's function. ZGNRs are C–H2 bonded at one edge and C–H bonded at the other edge to form asymmetric edge hydrogenation. The spin-polarized currents of ZGNR-based nano-devices with an odd or even number of the zigzag-shaped chains show a perfect bipolar spin-filtering effect on parallel and anti-parallel magnetic configurations. This study provides insights into the design of high-performance graphene-based spin filters.