Uniform hexagonal graphene film growth on liquid copper surface: Challenges still remain

Abstract

In a recent publication Geng et al. (1) reported the growth of graphene thin films on liquid Cu surface, using chemical vapor deposition. The authors state that the graphene nucleation typically occurs on grain boundaries in solid polycrystalline Cu, which results in an inhomogeneous density and size distribution of hexagonal graphene flakes. Therefore, liquefaction of the Cu leads to the formation of a uniform single-layer graphene. Although I agree with the general description and the fact that liquefaction of polycrystalline Cu will eliminate grain boundaries, I think the conclusion that it leads to the synthesis of continuous, uniform graphene film in general is misleading.