Macroscopic self standing SWCNT fibers as efficient electron emitters with very high emission current for robust cold cathodes

A novel of self-standing nanotube-based cold cathode is described. The electron emitter is a single macroscopic fibre spun from neat single wall carbon nanotubes and consists of an ensemble of nanotube bundles held together by van der Waals forces. Field emission measurements carried out using two different types of apparatus demonstrated the long working life of the realised cathode. The system is able to emit at very high current densities, up to 13 A/cm2, and shows very low values of both turn on and threshold field, 0.12 V/lm and 0.21 V/lm, respectively. Such easy to handle self-standing electron sources assure good performances and represent an enabling technology for a scalable production of cold cathodes. 2012 Elsevier Ltd. All rights reserved. 1. Introduction Due to a unique combination of properties, including high electrical and thermal conductivity, and high mechanical/ chemical/thermal stability, carbon nanotubes (CNTs) have been recognised as ideal candidate materials for application in microelectronics [1]. Moreover, the high aspect ratio characterising this intriguing material makes possible to significantly strengthen electric fields into the vicinity of nanotubes tips.