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

摘要

A novel of self-standing nanotube-based cold cathode is described. The electron emitter isuda single macroscopic fibre spun from neat single wall carbon nanotubes and consists of anudensemble of nanotube bundles held together by van der Waals forces. Field emission measurementsudcarried out using two different types of apparatus demonstrated the long workingudlife of the realised cathode. The system is able to emit at very high current densities, upudto 13 A/cm2, and shows very low values of both turn on and threshold field, 0.12 V/lm andud0.21 V/lm, respectively. Such easy to handle self-standing electron sources assure goodudperformances and represent an enabling technology for a scalable production of coldudcathodes.ud 2012 Elsevier Ltd. All rights reserved.ud1. IntroductionudDue to a unique combination of properties, including highudelectrical and thermal conductivity, and high mechanical/udchemical/thermal stability, carbon nanotubes (CNTs) haveudbeen recognised as ideal candidate materials for applicationudin microelectronics [1]. Moreover, the high aspect ratio characterisingudthis intriguing material makes possible to significantlyudstrengthen electric fields into the vicinity ofudnanotubes tips.