Controllable seeding of single crystal graphene islands from graphene oxide flakes

Graphene oxide (G-O) flakes were used to seed the growth of single crystal graphene islands by chemical vapor deposition (CVD) on Cu foil. Such islands have the G-O seed (which converts to a ‘reduced graphene oxide’ (rG-O) seed due to the CVD growth conditions used) roughly in the center of the islands. The lateral growth of such single crystal graphene islands was studied by carbon isotope labeling and Raman spectroscopy, scanning and transmission electron microscopy and selected area electron diffraction. By changing the concentration of G-O in the aqueous dispersion used to deposit the G-O flakes onto the Cu foil by dip-coating, the size of the seeded graphene islands could be precisely controlled on the Cu foil. The crystal orientation of the single crystal graphene islands was found to be identical to that of the G-O seeds.