title: High brightness electron beam from a multi-walled carbon nanotube.
abstract: Carbon nanotubes can act as electron sources with very rigid structures, making them particularly interesting for use as point electron sources in high-resolution electron-beam instruments. Promising results have been reported with respect to some important requirements for such applications: a stable emitted current and a long lifetime. Two parameters of an electron source affect the resolution of these instruments: the energy spread of the emitted electrons and a parameter called the reduced brightness, which depends on the angular current density and the virtual source size. Several authors have measured a low energy spread associated with electron emission. Here we measure the reduced brightness, and find a value that is more than a factor of ten larger than provided by state-of-the-art electron sources in electron microscopes. In addition, we show that an individual multi-walled carbon nanotube emits most current into a single narrow beam. On the basis of these results, we expect that carbon nanotube electron sources will lead to a significant improvement in the performance of high-resolution electron-beam instruments.
authors.affiliation: Philips Research Laboratories, Prof. Holstlaan 4, 5656 AA Eindhoven, The Netherlands. niels.de.jonge@philips.com
authors.forename: Niels
authors.initials: N
authors.lastname: de Jonge
authors.forename: Yann
authors.initials: Y
authors.lastname: Lamy
authors.forename: Koen
authors.initials: K
authors.lastname: Schoots
authors.forename: Tjerk H
authors.initials: TH
authors.lastname: Oosterkamp