Electronic structure of graphene/Y2C heterostructure and related doping effect

Until now, many attempts have been made to dope graphene in various ways, but each method turned out to have pros and cons. In this study, to overcome the limitations of doping methods, yttrium hypocarbide (Y₂C) is investigated as one prospective material to dope graphene, using density functional theory calculations. In monolayer Y₂C, the anionic electrons localized away from Y atomic layers are confirmed to contribute to occupied states near the Fermi level. Next, we investigate the electronic structure of graphene in heterojunction with Y₂C. Anionic electrons of Y₂C occupy the empty states of graphene in graphene/Y₂C heterostructure, which makes the Dirac cone of graphene located at about 1.7 eV below the Fermi level. Such charge transfer of anionic electrons to graphene and the flatness of electric cloud of anionic electrons leads to evenly n-doped graphene in graphene/Y₂C heterostructure. This suggests that Y₂C is a good candidate to dope graphene.