Structural Evolution of Many-Layer Epitaxial Graphene on 4H-SiC During Low-Energy Ion Implantation

The ability to modify graphene with defects and chemisorption is of interest for its potential to tailor graphene’s physical properties, including induced p-orbital magnetism that could be useful for spintronics. As a pathway towards these goals, we have investigated the behavior of multilayer epitaxial graphene implanted by low-energy ions (360-2000 eV) of H, D and He. In situ x-ray scattering reveals that the ions expand the spacing between graphene layers, which depends on the type of ion, the fluence, as well as whether the range of the ion distribution resides at the buried interface or within the graphene. Neutron reflectivity measurements show that H remains chemisorbed in the graphene. We show that the apparently different behavior among the ions and their distributions can be understood by a single concept and by the appropriate scaling of the data.