Graphene Amplification by Continued Growth on Seed Edges

Large-area single-layer graphenes with high crystallinity are desired for electronic applications. Here we demonstrate a continued growth method to amplify an existing graphene seed, originally grown by chemical vapor deposition, by preferentially inducing nucleation at seed edges. More specifically, this approach involves a surface oxidation step after the first growth, which leads to the observed formation of oxides at the vicinity of graphene edges, along with the inevitable formation of cracks due to oxidation, and thus limit growth predominantly at those edges, as a consequence of the reduced energy barrier of methane decomposition by oxygen moieties. Consequently, we successfully grow millimeter-size secondary single-crystal graphene structures with the same lattice structure and orientation as the original seeds. Selected area electron diffraction (SAED), Raman spectroscopy characterization, along with electronic transport measurement confirmed the structure coherence after the regrowth, even in the seed/regrown grains boundary region. This clone-like method provides a venue for production of graphene electronics with reproducible properties.