Structural and electronic properties of single-wall carbon nanotubes with various nitrogen content

The band structure of a carbon-nitrogen nanotube of zigzag type (8, 0) with nitrogen atom concentrations of 6.25%, 12.5%, and 25% and armchair (5, 5) carbon-nitrogen nanotube with nitrogen atom concentrations of 10% and 20% is calculated within the density functional theory approach. The calculations are carried out taking into account optimizations of both the longitudinal and transverse nanotube structural parameters. The structure is distorted significantly both lengthwise and across with increasing nitrogen concentrations. In particular, their cross-sectional profile ceases to be a circle. Dependence of the energies of interband electronic transitions on the concentration of nitrogen can be observed in the form of a peak shift in the optical absorption spectrum. (C) 2012 American Institute of Physics. [doi: 10.1063/1.3674267]