Electronic properties of nitrogen-doped carbon nanotubes with strain: Ab initio method approach

Abstract

A theoretical study on the electronic structure of nitrogen-doped single-walled carbon nanotubes (SWCNTs) using density functional theory based on the projector-augmented wave method is presented. It is found that the electronic properties of the CNT were determined by the nitrogen doping, uniaxial strain, and the size of the CNT. The nitrogen-doped CNTs turned out to have n-type semiconductor characteristics. However, the detailed change in electronic behavior varied with the specific condition of the CNT. Specifically, the density of states (DOS) for (5, 5) nanotubes exhibited a shift of the electronic spectrum. On the other hand, for the case of (10, 10) nanotubes, the band gap was narrowed by nitrogen doping owing to the existence of nitrogen states near the conduction band minimum. Interestingly, the applied strain did not affect the electronic structure of the (10, 10) CNT. However, in the case of the 5% nitrogen-doped (5, 5) CNT, the difference in the electronic structure was enhanced markedly with applied strain, unlike in the case of other armchair CNTs.