An investigation was made of the electronic properties of metallic (7,7) carbon nanotubes in the presence of a variety of tetra- and hexa-vacancy defects, by using the first principles density functional theory combined with the non-equilibrium Green’s function technique. From the view point of energetic stability large vacancies tend to split into pentagon and heptagon (5–7) defects. However, this did not preclude the presence of “holes” in the carbon nanotube by the nanoelectronic lithography technique. It was shown that the states linked to large vacancies hybridize with the extended states of the nanotubes to modify their band structure. As a consequence, the hole-like defects in the carbon nanotube led to more prominent electronic transport compared to the situation in the defective carbon nanotube consisting of pentagon–heptagon pair defects. The study suggested the possibility of improving the electronic properties of a defective carbon nanotube via morphological modifications induced by irradiation.

Vacancy Cluster-Limited Electronic Transport in Metallic Carbon Nanotube. H.Zeng, J.P.Leburton, H.Hu, J.Wei: Solid State Communications, 2011, 151[1], 9-12