Nitrogen doping of single walled carbon nanotubes by low energy N2+ ion implantation

Nitrogen doping in single walled carbon nanotubes by 300 eV N-2(+) ion implantation has been studied with X-ray photoelectron spectroscopy We investigated the nitrogen doping concentration in the range of 1.5-11.3 at.% and post-irradiation annealing up to 1000 degrees C. We found that nitrogen atoms can be substitutionally inserted into the perfect sp(2) hexagonal network, or bind to two sp(2) carbon neighbors in a pyridine-like configuration, or be connected to three or four sp(3) carbon atoms in a reconstructed double vacancy site and that the substitutional doping is the most stable bonding against high temperature annealing. (C) 2008 Elsevier Ltd. All rights reserved.