The electronic behavior of metallic carbon nanotubes under the influence of externally applied electric fields was investigated using the non-equilibrium Green’s function method, self-consistently coupled with three-dimensional electrostatics. A nearest-neighbor tight-binding model based upon a single orbital for constructing the device Hamiltonian was used. The three-dimensional Poisson equation was solved using the finite-element method. Carbon nanotubes exhibited a very weak metallic behavior, and external electric fields could significantly alter the electrostatic potential of the tubes. A single vacancy defect in the channel of a metallic carbon nanotube could decrease its conductance by a factor of two. More than one vacancy could further decrease the conductance.

Non-Equilibrium Green’s Function (NEGF) Simulation of Metallic Carbon Nanotubes Including Vacancy Defects. N.Neophytou, S.Ahmed, G.Klimeck: Journal of Computational Electronics, 2007, 6[1-3], 317-20