On the mechanisms of precipitation of graphene on nickel thin films
LPICM CNRS École polytechnique - Palaiseau 91120, France, EU
2 Department of Energy Science, Sungkyunkwan University - Suwon 440-746, Korea
Accepted: 2 October 2011
Growth on transition metal substrates is becoming a method of choice to prepare large-area graphene foils. In the case of nickel, where carbon has a significant solubility, such a growth process includes at least two elementary steps: 1) carbon dissolution into the metal, and 2) graphene precipitation at the surface. Here, we dissolve calibrated amounts of carbon in nickel films, using carbon ion implantation, and annealing at 725 ○C or 900 ○C. We then use transmission electron microscopy to analyse the precipitation process in detail: the latter appears to imply carbon diffusion over large distances and at least two distinct microscopic mechanisms.
PACS: 68.65.Pq – Graphene films / 81.05.ue – Graphene / 81.16.Hc – Catalytic methods
© EPLA, 2011