Field emission properties of CNT-based heterojunction emitters

Abstract

An approach to the preparation of a new type of field emitter that is made up of CNTs coated with amorphous carbon nitride (a-CNx) films is presented for the purpose of enhancing its electron emission property. CNTs were directly grown on nano-sized conical-type tungsten tips via the inductively coupled plasma-chemical vapor deposition (ICP-CVD) system, and a-CNx films were coated on the CNTs using an RF magnetron sputtering system. The morphologies and microstructures of the a-CNx-coated CNTs were analyzed via FESEM, EDX, and HRTEM. The electron emission properties of the a-CNx/CNT hetero-structures were measured using a high-vacuum field emission measurement system. The best field emission properties, such as a very low turn-on voltage of 500 V and a maximum emission current of 176 μA were achieved for the CNT emitter coated with the 5 nm-thick a-CNx film. In addition, this emitter showed a highly stable behavior in long-term (up to 25 h) electron emission.