Influence of the electronic structure on the field electron emission from carbon nanotubes

The classical statistical-tunneling approach for the electron field emission is applied for carbon nanotubes. Detailed computations for differential emission currents reveal very close peak shapes for the armchair and zigzag geometries, thus suggesting there is very little influence of the form of the electronic energy dispersion relations on the bulk field emission currents. For carbon nanotubes of practical width, an approximate semianalytical procedure is developed to compute the differential and total emission currents for virtually any type of dispersion relations. After validation for the armchair and zigzag geometries, this procedure may be further simplified into the frame of a fictitious confined two-dimensional free electron model. Some conclusions are drawn from the comparison of the computed field emission currents (through the simplified procedure) with present experimental data and a fully analytical expression for the total bulk field emission current is obtained for practical use. (C) 2003 American Vacuum Society.