Field emission characteristics of point emitters fabricated by a multiwalled carbon nanotube yarn

We fabricated point emitters using a multiwalled carbon nanotube (MWCNT) yarn which was treated by ethylene glycol. The point emitter showed a very high emission current of 3.01 mA (current density of 1.1 x 108 A cm-2) and good emission stability of over 20 h. We attributed the excellent field emission properties to a large field enhancement factor caused by the large aspect ratio of the sharp tip of the point emitter and the tight bonding of neighboring MWCNTs due to the ethylene glycol treatment. We investigated the field enhancement factor according to the gap between the anode and the emitter tip at a macroscopic gap regime. The measured field enhancement factor of the MWCNT point emitter was in good agreement with theoretical models.