Field emission from coated nanowires

This work investigates radial field emission from an Al-coated nanowire due to a time harmonic incident electromagnetic field. An analytical expression for the electric field inside and outside a smooth nanowire is derived. Through the boundary perturbation technique, this expression is corrected to include the effects of roughness of the nanowire surface. The corrected electric field is used to calculate the potential energy of the electromagnetic field in order to estimate the resulting current density. The Wentzel-Krammers-Brillouin approximation is employed in order to estimate the tunneling probability of the electrons in the metal due to the external electromagnetic potential. For the field-emission calculations, the free-electron model is invoked. The results indicate that at sufficiently low frequencies, the perturbative corrections do not influence the critical conditions for emission or the current density. (c) 2005 American Institute of Physics.