title: Identification of nitrogen dopants in single-walled carbon nanotubes by scanning tunneling microscopy.
abstract: Using scanning tunnelling microscopy and spectroscopy, we investigated the atomic and electronic structure of nitrogen-doped single walled carbon nanotubes synthesized by chemical vapor deposition. The insertion of nitrogen in the carbon lattice induces several types of point defects involving different atomic configurations. Spectroscopic measurements on semiconducting nanotubes reveal that these local structures can induce either extended shallow levels or more localized deep levels. In a metallic tube, a single doping site associated with a donor state was observed in the gap at an energy close to that of the first van Hove singularity. Density functional theory calculations reveal that this feature corresponds to a substitutional nitrogen atom in the carbon network.
authors.affiliation: Laboratoire Matériaux et Phénomènes Quantiques, UMR7162, Université Paris Diderot-Paris 7, Sorbonne Paris Cité, CNRS, UMR 7162 case courrier 7021, 75205 Paris Cedex 13, France. yann.tison@univ-paris-diderot.fr
authors.forename: Yann
authors.initials: Y
authors.lastname: Tison
authors.forename: Hong
authors.initials: H
authors.lastname: Lin
authors.forename: Jérôme
authors.initials: J
authors.lastname: Lagoute
authors.forename: Vincent
authors.initials: V
authors.lastname: Repain
authors.forename: Cyril
authors.initials: C
authors.lastname: Chacon
authors.forename: Yann
authors.initials: Y
authors.lastname: Girard
authors.forename: Sylvie
authors.initials: S
authors.lastname: Rousset
authors.forename: Luc
authors.initials: L
authors.lastname: Henrard
authors.forename: Bing
authors.initials: B
authors.lastname: Zheng
authors.forename: Toma
authors.initials: T
authors.lastname: Susi
authors.forename: Esko I
authors.initials: EI
authors.lastname: Kauppinen
authors.forename: François
authors.initials: F
authors.lastname: Ducastelle
authors.forename: Annick
authors.initials: A
authors.lastname: Loiseau