Single atomic-vacancy related changes in the geometry and electronic structure of the single-walled C nanotube tip were revealed by the first-principles calculation. A distorted pentagon–octagon pair was formed in situ. The localized states, induced by the dangling bond, mainly dominated the edges of occupied and unoccupied states and filled the gap. The electron emission property of defected tubes became worse because the advantageous contribution from electronic effects was a bit smaller than the disadvantageous contribution from geometrical effects. Their electron emission behavior and pattern were mostly determined by the dangling bond at the octagon.

Atomic-Vacancy Effects on Field Electron Emission of Carbon Nanotubes - a First-Principles Study. G.Zhou, W.Duan: Chemical Physics Letters, 2006, 423[1-3], 229-33