Chemical Vapor-Deposited Graphene on Ultraflat Copper Foils for van der Waals Hetero-Assembly

The purity and morphology of the copper surface is important for the synthesis of high-quality, large-grained graphene by chemical vapor deposition. We find that atomically smooth copper foils-fabricated by physical vapor deposition and subsequent electroplating of copper on silicon wafer templates-exhibit strongly reduced surface roughness after the annealing of the copper catalyst, and correspondingly lower nucleation and defect density of the graphene film, when compared to commercial cold-rolled copper foils. The ultrafoils-ultraflat foils -facilitate easier dry pickup and encapsulation of graphene by hexagonal boron nitride, which we believe is due to the lower roughness of the catalyst surface promoting a conformal interface and subsequent stronger van der Waals adhesion between graphene and hexagonal boron nitride.

Automated summary

The purity and morphology of the copper surface play an important role in synthesizing high-quality graphene using chemical vapor deposition. Smooth copper foils fabricated through physical vapor deposition and subsequent electroplating exhibit lower surface roughness after annealing, leading to lower nucleation and defect density in the graphene film. These ultraflat foils facilitate the easier dry pickup and encapsulation of graphene by hexagonal boron nitride, likely due to the conformal interface and stronger van der Waals adhesion between them.