Electronic structure of nanotubes doped by nitrogen, boron or oxygen

The effect of boron, nitrogen and oxygen impurity atoms on the band structure of carbon nanotubes with semiconductor or metallic conductivity was studied. The linearized augmented cylindrical waves method was employed to calculate electron scattering and density-of-states curves for carbon nanotubes containing boron, nitrogen or oxygen atoms as substitutional impurities. Doping of metallic carbon nanotube is accompanied by a shift of the Fermi level and an order-of-magnitude increase in the density of states at this level. In doped semiconductor nanotubes the band diagram changes from a semiconductor to a metallic character: the Fermi level shift from the bandgap to the conduction band (upon nitrogen or oxygen doping) or to the valence band (upon boron doping)