The energy band structures, optical absorption spectra and reflectivity of the semiconducting single-wall carbon nanotubes (7,0) and (8,0), with symmetrical Stone-Wales defects on (7,0) and symmetrical Stone-Wales defects on (8,0) and (7,0)-(8,0) single-walled carbon nanotube heterojunctions were studied using density functional theory. It was shown that the energy band structures had obviously changed and, according to the kind of defect, the Fermi energy levels were shifted in different directions. The absorption and reflectivity obviously weakened, and a red-shift of the absorption and reflectivity peaks occurred in the lower-energy region when the carbon nanotube contained topological defects, as compared with perfect single-wall carbon nanotubes. There was a distinct peak in the carbon nanotubes at a photon energy of about 13eV, and the peak shifted to higher energy when the nanotube contained defects.

Effects of Topological Defects on the Electronic Structure and Optical Spectrum of Single-Wall Carbon Nanotubes. F.Xie, H.F.Hu, J.W.Wei, H.Zeng, P.Peng: Spectroscopy and Spectral Analysis, 2007, 27[7], 1267-70