Electron field emission properties of vertically aligned carbon nanotube point emitters

We fabricated vertically aligned carbon nanotube (CNT) point emitters directly on Cu wires with flat or sharp tips. The nanostructures and field emission properties of the two kinds of emitters were investigated. Both emitters showed vertically aligned, multi-walled bamboo-liked CNT structures and demonstrated good field emission properties. The emitter on the Cu wire with a flat tip (F-tip) attained an emission current of 70 μA at 4200 V whereas the emitter on the Cu wire with a sharp tip (S-tip) reached an emission current of 65 μA at 3700 V. Both of them demonstrated excellent field emission stability for 40 h at emission currents of about 40 μA and 10 μA for the F-tip and S-tip emitters, respectively.

► Carbon nanotube point emitters were directly grown on Cu wires with flat tip or sharp tip using PECVD.
► The emitter on Cu flat tip attained an emission current of 70 μA at 4200 V.
► The emitter on Cu sharp tip reached an emission current of 65 μA at 3700 V.
► The point emitters showed high current stability during a 40 h test.
► The good emission property is attributed to the point emitter structure and ohmic contact between CNT and Cu tip.