Using the Graphene Moire Pattern for the Trapping of C-60 and Homoepitaxy of Graphene

The graphene Moire superstructure offers a complex landscape of humps and valleys to molecules adsorbing and diffusing on it. Using C-60 molecules as the classic hard sphere analogue, we examine its assembly and layered growth on this corrugated landscape. At the monolayer level, the cohesive interactions of C-60 molecules adsorbing on the Moire lattice freeze the molecular rotation of C-60 trapped in the valley sites, resulting in molecular alignment of all similarly trapped C-60 molecules at room temperature. The hierarchy of adsorption potential well on the Moire lattice causes diffusion-limited dendritic growth of C-60 films, as opposed to isotropic growth observed on a smooth surface like graphite. Due to the strong binding energy of the C-60 film, part of the dentritic C-60 films polymerize at 850 K and act as solid carbon sources for graphene homoepitaxy. Our findings point to the possibility of using periodically corrugated graphene in molecular spintronics due to its ability to trap and align organic molecules at room temperature.