Epitaxial Intercalation Growth of hBN/Graphene Bilayer Heterostructure on Commercial Copper Foil

The controlled growth of vertical van der Waals (vdW) heterostructures based on two-dimensional (2D) single crystals is crucial for the energy band modulation of 2D materials and related device applications. In this study, we investigated the epitaxial intercalation method to directly grow large-area hexagonal boron nitride (hBN)/graphene stacked vdW heterostructures on commercial copper foils. The method consists of three steps: growth of the top hBN template, hydrogen termination of the hBN edge, and intercalation growth of graphene between the hBN and a copper catalyst. In the intercalation step, compared with the conventional use of methane, a precursor with a lower hydrogen content, such as acetylene, is beneficial in maintaining the integrity of the hBN template. The ratio of hydrogen to acetylene determines the crystallization and quality of the intercalated graphene and hBN/graphene heterostructures. With our epitaxial intercalation method, we extend the bottom-up fabrication of large-scale high-quality vdW heterostructures.