▎ 摘　　要

In this paper, we study the spin-dependent electron transport properties of graphene n-p-n junction in the presence of Rashba spin-orbit interaction using transfer matrix method. It is found that for a graphene n-p-n junction, the spin-resolved electron conductance depends on the strength of Rashba spin-orbit interaction and the built-in potential of graphene junctions. For an appropriate value of Rashba strength, perfect electron spin-inversion with high conductance can take place when the graphene junction is biased with sufficient built-in potential. In this case, the graphene junction can be used as a spin-inverter which is an important device in spintronic. Finally, the spin-dependent conductance for a graphene n-n-n junction is investigated and compared with that of n-p-n junction. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4766812]