Visualizing In-Plane Junctions in Nitrogen-Doped Graphene

Controlling the spatial distribution of dopants in graphene is the gateway to the realization of graphene-based electronic components. Here, it is shown that a submonolayer of self-assembled physisorbed molecules can be used as a resist during a post-synthesis nitrogen doping process to realize a nanopatterning of nitrogen dopants in graphene. The resulting formation of domains with different nitrogen concentrations allows obtaining n–n’ and p–n junctions in graphene. A scanning tunneling microscopy is used to measure the electronic properties of the junctions at the atomic scale and reveal their intrinsic width that is found to be ≈7 nm corresponding to a sharp junction regime.