Carbon nanotube electron source for field emission scanning electron microscopy

Abstract

A carbon nanotube (CNT) is one of the promising candidates for next generation field emission materials. We have been studied emission properties of CNTs and reported that even a thick (φ ̃ 20 nm) multi-walled nanotube (MWNT) had a small emission area of about 5×10-14 cm 2, which resulted in brightness enhancement by 1-2 orders as compared with conventional tungsten field emission electron source. In this study, a single MWNT emitter is mounted on a commercially available field emission scanning electron microscope (FE-SEM). Focused ion beam nano-machinning and nano-manipulation methods are used to prepare MWNT emitters, and practicalities of these emitters for FE-SEM use (beam alignment, beam stability, life time, image quality and resolution) are investigated. As a result, it is proved that the MWNT emitter can be used as a replacement of a single crystalline tungsten emitter without any modification of an existing FE electron gun and its control system. © 2011 The Surface Science Society of Japan.