title: Electronic Structure Modification of Ion Implanted Graphene: The Spectroscopic Signatures of p- and n-Type Doping.
abstract: A combination of scanning transmission electron microscopy, electron energy loss spectroscopy, and ab initio calculations is used to describe the electronic structure modifications incurred by free-standing graphene through two types of single-atom doping. The N K and C K electron energy loss transitions show the presence of π* bonding states, which are highly localized around the N dopant. In contrast, the B K transition of a single B dopant atom shows an unusual broad asymmetric peak which is the result of delocalized π* states away from the B dopant. The asymmetry of the B K toward higher energies is attributed to highly localized σ* antibonding states. These experimental observations are then interpreted as direct fingerprints of the expected p- and n-type behavior of graphene doped in this fashion, through careful comparison with density functional theory calculations.
authors.affiliation: SuperSTEM Laboratory , SciTech Daresbury Campus, Daresbury WA4 4AD, United Kingdom.
authors.forename: Demie
authors.initials: D
authors.lastname: Kepaptsoglou
authors.affiliation: Institute for Materials Research, SCaPE, University of Leeds , Leeds LS2 9JT, United Kingdom.
authors.forename: Trevor P
authors.initials: TP
authors.lastname: Hardcastle
authors.affiliation: Institute for Materials Research, SCaPE, University of Leeds , Leeds LS2 9JT, United Kingdom.
authors.forename: Che R
authors.initials: CR
authors.lastname: Seabourne
authors.affiliation: School of Materials, University of Manchester , Manchester M13 9PL, United Kingdom.
authors.forename: Ursel
authors.initials: U
authors.lastname: Bangert
authors.affiliation: School of Materials, University of Manchester , Manchester M13 9PL, United Kingdom.
authors.forename: Recep
authors.initials: R
authors.lastname: Zan
authors.affiliation: II. Physikalisches Institut, Georg-August-Universität Göttingen , Friedrich-Hund-Platz 1, 37077 Göttingen, Germany.
authors.forename: Julian Alexander
authors.initials: JA
authors.lastname: Amani
authors.affiliation: II. Physikalisches Institut, Georg-August-Universität Göttingen , Friedrich-Hund-Platz 1, 37077 Göttingen, Germany.
authors.forename: Hans
authors.initials: H
authors.lastname: Hofsäss
authors.affiliation: Deparment of Materials, University of Oxford , Parks Road, Oxford OX1 3PH, United Kingdom.
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Nicholls
authors.affiliation: Institute for Materials Research, SCaPE, University of Leeds , Leeds LS2 9JT, United Kingdom.
authors.forename: Rik M D
authors.initials: RM
authors.lastname: Brydson
authors.affiliation: Institute for Materials Research, SCaPE, University of Leeds , Leeds LS2 9JT, United Kingdom.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Scott
authors.affiliation: SuperSTEM Laboratory , SciTech Daresbury Campus, Daresbury WA4 4AD, United Kingdom.
authors.forename: Quentin M
authors.initials: QM
authors.lastname: Ramasse
keywords: DFT; EELS; STEM; ab initio calculations; doping; electronic structure; graphene