Structure and electronic properties of single–walled zigzag BN and B۳C۲N۳ nanotubes using first-principles methods

The structure and the electronic properties of single-walled zigzag BN and B۳C۲N۳ nanotubes (n, ۰; n=۴–۱۰) were investigated using first-principles calculations based on a density functional theory. A plane–wave basis set with periodic boundary conditions in conjunction with Vanderbilt ultrasoft pseudo-potential was employed. The energy gap of ZB۳C۲N۳NTs was calculated and compared with the corresponding value for BNNTs. It was found that in both types of nanotube (BNNTs and B۳C۲N۳NTs), the band gap energy is increased as the diameter of the tubes becomes larger and also these nanotubes are semiconductors with direct band gap. Although the band gap energy of the BN tubes are much larger than that of B۳C۲N۳ ones, they have similar dependence on the diameter of the tubes and a semiconducting characteristic is maintained. There is a peak near the conduction band in B۳C۲N۳NT nanotubes. Thus, energy gaps are reduced. These kind of ternary BCN nanotubes are of n–type semiconductors.