title: Growth of adlayer graphene on Cu studied by carbon isotope labeling.
abstract: The growth of bilayer and multilayer graphene on copper foils was studied by isotopic labeling of the methane precursor. Isotope-labeled graphene films were characterized by micro-Raman mapping and time-of-flight secondary ion mass spectrometry. Our investigation shows that during growth at high temperature, the adlayers formed simultaneously and beneath the top, continuous layer of graphene and the Cu substrate. Additionally, the adlayers share the same nucleation center and all adlayers nucleating in one place have the same edge termination. These results suggest that adlayer growth proceeds by catalytic decomposition of methane (or CH(x), x < 4) trapped in a "nano-chemical vapor deposition" chamber between the first layer and the substrate. On the basis of these results, submillimeter bilayer graphene was synthesized by applying a much lower growth rate.
authors.affiliation: Department of Physics, Laboratory of Nanoscale Condense Matter Physics, Xiamen University, Xiamen, China 361005.
authors.forename: Qiongyu
authors.initials: Q
authors.lastname: Li
authors.forename: Harry
authors.initials: H
authors.lastname: Chou
authors.forename: Jin-Hui
authors.initials: JH
authors.lastname: Zhong
authors.forename: Jun-Yang
authors.initials: JY
authors.lastname: Liu
authors.forename: Andrei
authors.initials: A
authors.lastname: Dolocan
authors.forename: Junyan
authors.initials: J
authors.lastname: Zhang
authors.forename: Yinghui
authors.initials: Y
authors.lastname: Zhou
authors.forename: Rodney S
authors.initials: RS
authors.lastname: Ruoff
authors.forename: Shanshan
authors.initials: S
authors.lastname: Chen
authors.forename: Weiwei
authors.initials: W
authors.lastname: Cai