Electronic Transport Properties Of Graphene Nano Device

Traditional semiconductor devices can no longer meet people’s needs whilenumber of transistors on an integrated circuit dramatically increased. Spintronics, wherethe spin of electrons is used to carry information, has developed rapidly. The search fora material, that has great properties for both electronics and spintronics, has been animportant issue in both electronics and spintronics devices.Since found in2004, the unique electronic properties of graphene, including highmobility and linear dispersion, continue to attract significant interest. It will become thecore material for future electronic devices.This dissertation focuses on the electronic transport properties of graphenenanoribbions. By solving Dirac’s equation, the transfer-matrix method and Prague-likereflection method are used to study different graphene nanoribbions systems.The present studies include the following aspects:(1) Spin-filting effect in ferromagnetic graphene junctions. The result shows thatthe junction acts as a spin filter with full spin polarization at non-zero angle of incidence.By applying a gate voltage, the spin-filtering efficiency of this device can be effectivelycontrolled.(2) Effect of a velocity barrier on the thermopower of graphene. In this chapter wetheoretically investigate the thermoelectric properties of ballistic graphene nanoribbons(GNRs) in the presence of a velocity barrier, in which a different value of Fermivelocity from the one in the surrounding background is considered..(3) Spin polarization in an asymmetric magnetic graphene superlattice. In thischapter we investigate the spin-resolved transport through an asymmetrical magneticgraphene superlattice (MGS) consisting of the periodic barriers with abnormal one inheight.(4) Electron transport in graphene-based non-parallel double barriers. In thischapter, transport in the graphene-based nonparallel double barriers has beeninvestigated by Prague reflection method. We show that electron transport exhibit astrong dependence on the angle between the non-parallel barriers. (5) Conclusions of this paper and future work.