Graphene Crystal Growth Engineering on Epitaxial Copper Thin Films

In this work 1 , we study graphene growth dynamics on epitaxial Cu thin film substrates by chemical vapor deposition (CVD). These surfaces have a single crystallographic orientation and are atomically smooth, unlike their foil counterparts, making them better platforms on which to reproducibly synthesize highquality graphene and study crystal growth evolution. Consequently, we gained novel insight into the key mechanisms and factors that influence graphene growth dynamics, such as Mullins-Sekerka morphological instabilities, Cu surface orientation, hydrogen-to-methane flux ratio (H2:CH4), absolute pressure, and nucleation density. We demonstrate how the various graphene morphologies that are commonly reported in literature, such as lobes, dendrites, hexagrams, and hexagons, can be selectively synthesized over large areas by controlling critical CVD parameters. In particular, growth on Cu(111) can be tuned to yield high-quality, large-scale, single-crystalline graphene monolayers, a feat that is not possible on Cu foil due to the rotational grain boundaries that exist when graphene islands on neighboring Cu facets merge.