Abstract Submitted to the    NANOTUBE'04 Conference:

The research is aimed at developing a new type of electron source for electron microscopes to improve their resolution. Electron sources were constructed from individual carbon nanotubes by mounting them on tungsten tips using a nano-manipulator [1,2]. The electron emission of thin multi-walled nanotubes, as well as nitrogen-doped multi-walled carbon nanotubes has been studied and important parameters such as energy spread of the emitted electron beam, emission pattern, angular current density, current stability and brightness were measured. It was found that upon thorough cleaning of the nanotube surface, the emission process is field emission as described by the Fowler Nordheim theory. A workfunction of 5 eV was determined. Compared to the state of the art commercial sources, the nanotube source shows a lower energy spread than the Schottky emitter and a better current stability than the cold-field emission gun (CFEG). The source provides an extremely high brightness: 3x10 ⁹ Asr^-1m^-2V^-1 - an order of magnitude larger than that of the Schottky emitter and the CFEG [1,3].

References:

[1] N. de Jonge, Y. Lamy, K. Schoots, T.H. Oosterkamp, Nature 420, 393 (2002).
[2] N. de Jonge, Y. Lamy, M. Kaiser, Nano Letters 3, 1621 (2003).
[3] N. de Jonge, J. Appl. Phys. 95, 673 (2003).