Growth from below: Bilayer graphene on copper by chemical vapor deposition

Abstract

We evaluate how a second graphene layer forms and grows on Cu foils during chemical vapor deposition (CVD). Low-energy electron diffraction and microscopy is used to reveal that the second layer nucleates and grows next to the substrate, i.e., under a graphene layer. This underlayer mechanism can facilitate the synthesis of uniform <i>single-layer</i> films but presents challenges for growing uniform <i>bilayer</i> films by CVD. We also show that the buried and overlying layers have the same edge termination.