Electron side-emission from corrugated CNx nanotubes

Horizontally grown and vertically aligned carbon nitrogen (CNx) nanotubes encapsulated with Fe2O3 particles were synthesized on silicon substrates. Electron field-emission measurements were carried out on these CNx nanotubes using both the top-emission and side-emission geometries, and compared with that of the usual carbon nanotubes (CNTs). It was found that the turn-on field of the CNx nanotubes is at least similar to2 V/mum less and the field conversion factor under low bias voltage is about four times more than that of the CNTs. For the two types of CNx films, the field emission property of the horizontally grown honeycombed film is clearly better than that of the vertically aligned film, indicating that for the corrugated nanotubes the "side-emission" geometry is superior to the more widely used "top-emission" geometry. Electrostatic potential distributions were calculated for some simplified models of the nanotubes, these calculations suggest that the enhanced field-emission of the "side-emission" geometry could be attributed to the increased corrugation and lowered potential barrier along the side of the corrugated nanotube compared with that along the top of the usual carbon nanotube. (C) 2004 American Institute of Physics.