▎ 摘　　要

Graphene ribbons, which may be fabricated by a wide variety of experimental techniques such as chemical processing, unzipping or etching of carbon nanotubes, molecular precursors, ion implantation, and so on, can find promising applications in interconnects, terahertz sensors, and plasmonic devices. Here we report measurements on self-assembled graphene ribbons that are prepared by a controlled high-temperature sublimation technique. The epitaxial graphene ribbons on SiC can be readily and efficiently located by confocal laser scanning microscopy for device fabrication using a removable metal protection layer to avoid contamination of the graphene and hexagonal boron nitride to serve as a top-gate dielectric spacer. These self-assembled graphene ribbons have smooth edges, and the observation of a magnetoresistance side peak in such a structure is consistent with diffusive boundary scattering in the quasi-ballistic regime. In contrast, graphene ribbons defined by electron-beam lithography and subsequent conventional reactive ion etching on the same SiC wafer only show pronounced negative magnetoresistance due to strong disorder in the edge structures (chemical dopants, the resolution of electron-beam lithography, etc.). Our experimental approaches are applicable to wafer-scale, graphene-based integrated circuits.