Modeling of the electron field emission from carbon nanotubes

Using a tunneling approach for the field emission from a single carbon nano tube, expressions for the emission current as a function of the anode volta ge and of the emitted electron energy spectrum are obtained. The low dimens ionality of the electronic system of a carbon nanotube is taken into accoun t. The extraction field on the nanotube's tip is evaluated using numerical computations. For nanotubes of practical interest, having large enough diam eters, it is demonstrated that the influence of the detailed form of the el ectron energy dispersion relations is not of major importance. This influen ce could be generally embedded in a numerical factor entering the expressio n of the emission current. The influence of the various tube parameters on the characteristics is also identified and analyzed. An approximate formula for use in practical analysis in field emission is deduced and its validit y for different nanotube sizes is verified. (C) 2001 American Vacuum Societ y.