Generally, it is supposed that the Fermi level in epitaxial graphene is controlled by two effects: p-type polarization doping induced by the bulk of the hexagonal SiC(0001) substrate and overcompensation by donor-like states related to the buffer layer. In this work, we evidence that this effect is also related to the specific underlying SiC terrace. We fabricated a periodic sequence of non-identical SiC terraces, which are unambiguously attributed to specific SiC surface terminations. A clear correlation between the SiC termination and the electronic graphene properties is experimentally observed and confirmed by various complementary surface-sensitive methods. We attribute this correlation to a proximity effect of the SiC termination-dependent polarization doping on the overlying graphene layer. Our findings open a new approach for a nano-scale doping-engineering by self-patterning of epitaxial graphene and other 2D layers on dielectric polar substrates.
@article{arxiv.2006.00359,
title = {Silicon carbide stacking-order-induced doping variation in epitaxial graphene},
author = {Davood Momeni Pakdehi and Philip Schädlich and T. T. Nhung Nguyen and Alexei A. Zakharov and Stefan Wundrack and Florian Speck and Klaus Pierz and Thomas Seyller and Christoph Tegenkamp and Hans. W. Schumacher},
journal= {arXiv preprint arXiv:2006.00359},
year = {2020}
}