title: Chemically homogeneous and thermally reversible oxidation of epitaxial graphene.
abstract: With its exceptional charge mobility, graphene holds great promise for applications in next-generation electronics. In an effort to tailor its properties and interfacial characteristics, the chemical functionalization of graphene is being actively pursued. The oxidation of graphene via the Hummers method is most widely used in current studies, although the chemical inhomogeneity and irreversibility of the resulting graphene oxide compromises its use in high-performance devices. Here, we present an alternative approach for oxidizing epitaxial graphene using atomic oxygen in ultrahigh vacuum. Atomic-resolution characterization with scanning tunnelling microscopy is quantitatively compared to density functional theory, showing that ultrahigh-vacuum oxidization results in uniform epoxy functionalization. Furthermore, this oxidation is shown to be fully reversible at temperatures as low as 260 °C using scanning tunnelling microscopy and spectroscopic techniques. In this manner, ultrahigh-vacuum oxidation overcomes the limitations of Hummers-method graphene oxide, thus creating new opportunities for the study and application of chemically functionalized graphene.
authors.affiliation: Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Md Zakir
authors.initials: MZ
authors.lastname: Hossain
authors.forename: James E
authors.initials: JE
authors.lastname: Johns
authors.forename: Kirk H
authors.initials: KH
authors.lastname: Bevan
authors.forename: Hunter J
authors.initials: HJ
authors.lastname: Karmel
authors.forename: Yu Teng
authors.initials: YT
authors.lastname: Liang
authors.forename: Shinya
authors.initials: S
authors.lastname: Yoshimoto
authors.forename: Kozo
authors.initials: K
authors.lastname: Mukai
authors.forename: Tatanori
authors.initials: T
authors.lastname: Koitaya
authors.forename: Jun
authors.initials: J
authors.lastname: Yoshinobu
authors.forename: Maki
authors.initials: M
authors.lastname: Kawai
authors.forename: Amanda M
authors.initials: AM
authors.lastname: Lear
authors.forename: Larry L
authors.initials: LL
authors.lastname: Kesmodel
authors.forename: Steven L
authors.initials: SL
authors.lastname: Tait
authors.forename: Mark C
authors.initials: MC
authors.lastname: Hersam
mesh_terms: D002384:Catalysis; D006108:Graphite / Q000737:chemistry*; D016252:Microscopy, Scanning Tunneling; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D013696:Temperature; D014618:Vacuum
chemical_list: D006108:Graphite; D010100:Oxygen