Irradiation-assisted substitution of carbon atoms with nitrogen and boron in single-walled carbon nanotubes

Doping of carbon nanotubes with boron and nitrogen should provide more control over the nanotube electronic structure. In addition to the chemical substitution and arc-discharge methods used nowadays, we suggest using ion irradiation as an alternative way to introduce B/N impurities into nanotubes. Making use of molecular dynamics with analytical potentials we simulate irradiation of single-walled nanotubes with B and N ions and show that up to 40% of the impinging ions can occupy directly the sp2 positions in the nanotube atomic network. We further estimate the optimum ion energies for the direct substitution. As annealing should further increase the number of sp2 impurities due to dopant atom migration and interaction with vacancies, irradiation-mediated doping of nanotubes is a promising way to control the nanotube electronic structure.