Direct growth of unidirectional spindle-shaped graphene nanoribbons on SiC

Direct growth of self-aligned spindle-shape graphene nanoribbons (GNRs) on SiC(11-20) substrate is demonstrated. It is found all the GNRs are monolayer and one of edges of each endpoint of GNR is along direction of zigzag-edge. The length directions of the GNRs are all coincided with the [0001] direction of SiC due to the anisotropy surface energy of SiC. Furthermore, the doping type of GNRs is p-type and its carrier density is changing with the variation of ribbon width. The size-dependent Fermi level variation in sub-micron scale GNR renders a P−P+P− potential configuration in a single GNR. The existed zigzag edges and a special potential configuration in a single GNR make it promise for fabrication of graphene based devices as triode and spintronic device.

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