Graphene p-n junction formed on SiC(0001) by Au intercalation

We propose a method to fabricate the chemical p-n junction in wafer-scale epitaxial graphene. In the case of Au intercalation in between graphene and SiC(0001), there exist two structurally distinct phases that result in p-type and n-type doping in the graphene layer, respectively. In the process of in situ Au deposition on our samples, we used a shadow mask to form a sharp junction of different Au coverage. The intercalation of Au atoms induced by thermal annealing leads to the abrupt p-n junction in the graphene layer, which is characterized by angle-resolved photoemission spectroscopy. This p-n junction of graphene is abrupt in the scale comparable to the beam size of approximately 50 μm. This p-n junction of graphene is expected to be atomically abrupt, since there exist only two structurally distinct phases by self-assembly. The proposed method may be useful not only to fabricate a wafer-scale p-n junction of graphene, but also for a fundamental study on atomically abrupt graphene p-n junction.