Why Are Carbon Nanotubes Such Excellent Field Emitters?
Jean-Marc Bonard, Thomas Stockli, Jean-Paul Salvetat, Laszlo Forro, and Andre Chatelain*
Department of Physics, Swiss Federal Institute of Technology, Lausanne CH-1015, Lausanne, Switzerland
This is an abstract
for a presentation given at the
Foresight Conference on Molecular Nanotechnology.
The full article is available at http://www.foresight.org/Conferences/MNT6/Papers/Chatelain/index.html.
We studied the electron field emission properties of single-wall and multi-wall carbon nanotubes, both as single emitters and in film form.
The nanotube field emitters show a good emission stability in the whole investigated current range (from <1 pA to 0.2 mA for one single tube). In comparision with other field emitters, operation voltages are typically 5-10 times lower for comparable emitted currents. At low currents the I-V characteristics follow the Fowler-Nordheim relation, but strong deviations from metallic behavior are systemically observed at high currents.
Our studies suggest that the large field amplilfication factor, arising from the small radius of curvature of the nanotube tips, is largely responsible for the good emission characteristics. However, the observation of light emission during electron field emission, as well as deviations from the Fowler-Nordheim law, sharp energy distributions, and non-homogenous emission patterns, strongly suggest that the density of states (DOS) at the tip is non-metallic. This DOS appears as localized states with well-defined energy bands, and influences greatly the emission behavior.
J.-M. Bonard et al. "Field emission induced luminescence from carbon nanotubes"
To appear in Phys. Rev. Lett. (August 1998)
J.-M. Bonard et al. " Field emission from single wall nanotubes films"
To appear in Appl. Phys. Lett. (August 1998)
Prof. Andre Chatelain
Inst. Physique Experimentale
1015 Lausanne Swizerland
telephone: 41-21-693-33-22-33-20; fax: 41-21-693-36-04