Morphology Effects of Graphene Seeds on the Quality of Graphene Nucleation: Quantum Chemical Molecular Dynamics Simulations

Abstract

The graphene growth on the Ni(111) surface in the presence of different graphene seeds C16 and C24 has been investigated at the atomic level by quantum chemical molecular dynamics simulations. The morphology effects of graphene seeds on the polygon growth behavior were explored by the random deposition of C2 species on the Ni(111) surface. The results demonstrated that in the presence of the graphene seeds, hexagons can be formed directly at the seed edges, different from the “pentagon-first” mechanism proposed before. At the edge of the seeds, different growth behaviors were observed depending on the specific edge structure. We found that the edge structures which are consisted of more carbon atoms prefer to form more hexagons, giving rise to the higher quality of graphene. Compared with the seed C16, C24 has more zigzag edge structures and is expected to produce more hexagons. This has been confirmed by our simulation, where the seed C24 produced higher quality graphene than C16. The results suggested that the morphology of the graphene seed could affect the quality of the graphene growth. Furthermore, the sequence growth along the edge structure of the seed is superior to the random growth on the metal surface.