Tuning electronic properties of carbon nanotubes by Boron and Nitrogen doping

The electronic properties of pure and doped carbon nanotubes and NC3-, BC3-, NC- and BC-nanotubes are investigated by using tight binding theory. It was found that applying the external fields and doping change the band gap. The energy gap is reduced by B/N-doping and the reduction value is sensitive to the several parameters such as nanotube diameter and chirality, external field strength, electric field direction, impurity type and concentration. The direct N (B) substitution creates a new band above (below) the Fermi level and leads to creation of n-type (p-type) semiconductor. The external fields modify the band structure and convert the doped nanotube into metal. For both XC and XC3 nanotubes (X=B/N), the gap energy reduction shows identical dependence to electric field and the XC3 nanotubes show more sensitive behavior to electric field rather than XC nanotubes. (C) 2016 Elsevier B.V. All rights reserved.