Graphene Nucleation at Front Ends of Copper Twin Crystal

The graphene is easily grown on polycrystalline copper foils using metal-catalyzed chemical vapor deposition (CVD). Annealing twin readily occurred during this CVD process. However, there are only a few reports on the role of annealing twin on the graphene growth. In this paper, we present the investigations of the influence of copper twin crystal onthe nucleation of graphene. We found that there is no selective formation of graphene on these annealing twin crystal in general conditions of graphene growth.Interestingly, graphene preferentially nucleates at the front ends of twin crystals. We propose a micro-mechanism to explain the preferential graphene nucleation site based on spiral growth phenomena of copper twin crystals.This work may enable new possibilities for the controllable nucleation and wafer-scale growth of single-crystal graphene.