Modulating charge density and inelastic optical response in graphene by atmospheric pressure localized intercalation through wrinkles (original) (raw)

Changes of paradigms, in terms of new functionalities, architectures, and performances, are foreseen with graphene, an atomically thin sheet of carbon atoms in a honeycomb lattice. These prospects are urging the development of efficient production methods. 1 Preparation by chemical vapor deposition (CVD), in this respect, has reached such maturity that graphene now appears as an alternative to indium tin oxide as a transparent conductive electrode 2 or to Si and II-IV semiconductors in high-frequency electronics. 3 Intercalation of species between the metallic substrate needed for CVD and graphene, a method known since the 1980's, 4 is an efficient and versatile way to achieve quasi free-standing graphene 5 and to engineer the properties of graphene, for instance to induce electronic band-gaps, 6 magnetic moments, 7 and strains. 8 Dual intercalation, of Si and O, even showed great promise for the transfer-free preparation of graphene-on-oxide field effect transistors. 9 Despite the numerous reports devoted to graphene/substrate intercalated systems, two key questions remain open. First, the surmised role of defects as pathways for intercalation has only been established, yet partially in some cases, for a few defects, namely graphene free edges 5 and point defects. 10,11 Unveiling other intercalation pathways will help better envisioning the full potentialities of intercalation for building up advanced graphene-based hybrids. Second, all studies of intercalation reported thus far were performed under ultra-high vacuum (UHV). While this approach offers optimum control over the processes, it is a prohibitively costly one in the view of the production of graphene decoupled from its substrate. While atmospheric pressure intercalation