Effect of substitutional atoms in carbon nanocones

We apply first-principles calculations to investigate the effect of introducing substitutional boron or nitrogen in carbon nanocones. The studies involve carbon nanocones with one and two pentagons in the tip. Nitrogen is shown to lower the energy of pentagon defect, while boron increases. On the other hand boron substitutional, on the pentagon, lowers the gap energy by 0.95 eV, while nitrogen increases by 0.06 eV. This suggests that the substitutional impurity could affect optical properties of carbon nanocones. (C) 2004 Elsevier B.V. All rights reserved.