Field Emission Characteristics of Carbon Nanotube Films Fabricated by Different Methods

In order to improve the performance of field emitters nowadays, carbon nanotubes are used instead of conventional materials such as silicon and metals. In this paper, field emission characteristics of three different multi-wall carbon nanotube films have been compared, which are fabricated by different methods, including direct growth, evaporation coating and flow assembly. The field emission current-voltage property of each film has been characterized experimentally, and the electric field enhancement factor has been analyzed using Fowler-Nordheim theory. Moreover, emission stability of each film has been measured too. It can be concluded that the direct-grown vertical multi-wall carbon nanotube array has turn-on field of 0.603 V/mum and current density fluctuation less than 5%, which is much lower than the other films by post-treatment processes.