Identification of nitrogen dopants in single-walled carbon nanotubes by scanning tunneling microscopy
Résumé
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. © 2013 American Chemical Society.
Mots clés
Atomic configuration
Nitrogen-doping
Scanning tunneling microscopy and spectroscopy
Scanning tunnelling microscopy and spectroscopy
Semi-conducting nanotubes
Spectroscopic measurements
Substitutional nitrogen
Van Hove singularities
Atoms
Carbon
Carbon nanotubes
Chemical vapor deposition
Density functional theory
Electronic structure
Point defects
Scanning tunneling microscopy
Single-walled carbon nanotubes (SWCN)
Nitrogen