Fig. 1
Ballistic transport in graphene sidewall ribbons on SiC mesa structures. Graphene nanoribbons (GNRs) can be selectively grown on SiC sidewalls as sketched in a. b Sequence of STM measurements performed at room temperature show the entirely overgrown SiC facet areas (+2 V, 0.5 nA, semi-insulating SiC). c High-resolution STM showing the overgrowth of the SiC facet and zigzag orientation (inset). The scale bars indicate a length of 2 nm (blue) and 0.4 nm (green). d The IV-curves measured in a two point probe assembly (2pp) clearly reveal a resistance of h/e2 on the GNR for a probe distance of 2 μm. The GNR can be easily seen also in SEM (inset, doped-SiC, scale bar, 1 μm). By means of a 4-tip STM the ribbons are contacted for in situ transport measurements
