title: Vibrational Excitations and Low Energy Electronic Structure of Epoxide-decorated Graphene.
abstract: We report infrared studies of adsorbed atomic oxygen (epoxide functional groups) on graphene. Two different systems are used as a platform to explore these interactions, namely, epitaxial graphene/SiC(0001) functionalized with atomic oxygen (graphene epoxide, GE) and chemically reduced graphene oxide (RGO). In the case of the model GE system, IR reflectivity measurements show that epoxide groups distort the graphene π bands around the K-point, imparting a finite effective mass and contributing to a band gap. In the case of RGO, epoxide groups are found to be present following the reduction treatment by a combination of polarized IR reflectance and transmittance measurements. Similar to the GE system, a band gap in the RGO sample is observed as well.
authors.affiliation: University of Wisconsin-Milwaukee, Physics Dept., Milwaukee, WI 53211.
authors.forename: E C
authors.initials: EC
authors.lastname: Mattson
authors.affiliation: University of Minnesota, Chemistry Dept, Minneapolis, MN 55455.
authors.forename: J E
authors.initials: JE
authors.lastname: Johns
authors.affiliation: University of Wisconsin-Milwaukee, Physics Dept., Milwaukee, WI 53211.
authors.forename: K
authors.initials: K
authors.lastname: Pande
authors.affiliation: Synchrotron Radiation Center, University of Wisconsin-Madison, Stoughton, WI 53589.
authors.forename: R A
authors.initials: RA
authors.lastname: Bosch
authors.affiliation: University of Wisconsin-Milwaukee, Mechanical Engineering Dept., Milwaukee, WI 53211.
authors.forename: S
authors.initials: S
authors.lastname: Cui
authors.affiliation: University of Wisconsin-Milwaukee, Physics Dept., Milwaukee, WI 53211.
authors.forename: M
authors.initials: M
authors.lastname: Gajdardziska-Josifovska
authors.affiliation: University of Wisconsin-Milwaukee, Physics Dept., Milwaukee, WI 53211.
authors.forename: M
authors.initials: M
authors.lastname: Weinert
authors.affiliation: University of Wisconsin-Milwaukee, Mechanical Engineering Dept., Milwaukee, WI 53211.
authors.forename: J H
authors.initials: JH
authors.lastname: Chen
authors.affiliation: Northwestern University, Chemistry Dept., Evanston, IL 60208 ; Northwestern University, Materials Science and Engineering Dept., Evanston, IL 60208.
authors.forename: M C
authors.initials: MC
authors.lastname: Hersam
authors.affiliation: University of Wisconsin-Milwaukee, Physics Dept., Milwaukee, WI 53211.
authors.forename: C J
authors.initials: CJ
authors.lastname: Hirschmugl
keywords: adsorbates; band structure; epitaxial graphene; oxygen; reduced graphene oxide; vibrations