Field emission from aligned carbon nanotubes prepared by thermal chemical vapor deposition of Fe-phthalocyanine

The field emission from aligned multiwalled carbon nanotubes prepared by thermal chemical vapor deposition of Fe-phthalocyanine is reported, with emphasis on the current–voltage characteristics and current fluctuation. By running of a pristine emitter at high current and/or voltage for a long time, the onset voltage is lowered from 400 to 125 V and the field-enhancement factor increases from 360 to 1110, demonstrating geometrical reconstruction of the nanotube apex. Deviation from the Fowler–Nordheim relation is caused at a constant local electric field of ∼4×103 V/μm and is related to high-field conditioning. Electron emission current under a high current density condition (>10 mA/cm2) is stable and noiseless. The reason for current noise in the lower current density is discussed.