Thermionic emission from defective carbon nanotubes

Using a nanomanipulation system contained within a scanning electron microscope we investigate the thermionic electron emission from multiwall carbon nanotubes. Peak emission currents of 65 nA are measured. The carbon nanotubes being grown at low temperature by the chemical vapor deposition method are defective with poor thermal conductivity. We believe it is crucial for the thermal conductivity to be poor in order to obtain significant thermionic emission from the carbon nanotubes. This allows for the carbon nanotube during electron emission to be at high temperatures, and thus give higher emission efficiencies. At the highest emission current levels we estimate the temperature of the nanotubes to be approximately 2900 K. (C) 2004 American Institute of Physics.