Abstract:
A bilayer graphene film obtained on copper (Cu) foil is known to have a significant fraction of
non-Bernal (AB) stacking and on copper/nickel (Cu/Ni) thin films is known to grow over a
large-area with AB stacking. In this study, annealed Cu foils for graphene growth were doped with
small concentrations of Ni to obtain dilute Cu(Ni) alloys in which the hydrocarbon decomposition
rate of Cu will be enhanced by Ni during synthesis of large-area AB-stacked bilayer graphene
using atmospheric pressure chemical vapour deposition. The Ni doped concentration and the Ni
homogeneous distribution in Cu foil were confirmed with inductively coupled plasma optical
emission spectrometry and proton-induced X-ray emission. An electron backscatter diffraction
map showed that Cu foils have a single (001) surface orientation which leads to a uniform growth
rate on Cu surface in early stages of graphene growth and also leads to a uniform Ni surface
concentration distribution through segregation kinetics. The increase in Ni surface concentration
in foils was investigated with time-of-flight secondary ion mass spectrometry. The quality of graphene,
the number of graphene layers, and the layers stacking order in synthesized bilayer graphene
films were confirmed by Raman and electron diffraction measurements. A four point probe station
was used to measure the sheet resistance of graphene films. As compared to Cu foil, the prepared
dilute Cu(Ni) alloy demonstrated the good capability of growing large-area AB-stacked bilayer
graphene film by increasing Ni content in Cu surface layer.
