Growth from Below: Bilayer Graphene on Copper by Chemical Vapor Deposition

TL;DR

This paper investigates the formation and growth mechanisms of bilayer graphene on copper during chemical vapor deposition, revealing an underlayer nucleation process that impacts film uniformity.

Contribution

It uncovers the underlayer growth mechanism of the second graphene layer on copper during CVD, which was previously not well understood.

Findings

Second graphene layer nucleates under the first layer

Buried and overlying layers have the same edge termination

Underlayer growth influences bilayer film uniformity

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 single-layer films but presents challenges for growing uniform bilayer films by CVD. We also show that the buried and overlying layers have the same edge termination.