Microstructure and electronic properties of the graphene/{111} copper interface modulated by the rotation angle

Abstract

Interfacial structure and characteristics of heterogeneous interfaces are essential for the macro-properties of composites. Particularly for graphene/metal heterojunctions, interface rotation angle variations may cause distinctions in interfacial electronic properties. However, direct experimental evidence is lacking in understanding the corresponding mechanisms. Here, we investigated influential mechanisms of rotation angle differences on interfacial electronic coupling in classical graphene/copper (Gr/Cu) immiscible epitaxial systems. Atomic force microscopy combined with surface potential measurement confirmed that the different rotation angles (∼8°) contributed to a modulated Fermi level in Gr/Cu, indicating varied electron transfer at the interface. Through theoretical analysis, it is found that the modulated interfacial electronic behavior is primarily ascribed to different overlap between C-p and Cu-3d orbitals, resulting from varying fluctuation of graphene and changed minimum Gr/Cu distance at different rotation angles. The mechanism of interfacial electronic properties modulated by the rotation angles could further guide the design of heterogeneous interfaces in electronic applications.