Electron field emission from nanostructured diamond and carbon nanotubes

Both diamond and carbon nanotubes are efficient field emitters because of t he negative electron affinity associated with the diamond surface and the g eometrically nanometer-scale nature of the nanotubes. They offer the import ant advantage of ease in fabrication and low-cost manufacturing. Both mater ials have been shown to emit electrons at very low electric fields (3-7 V/m um for a current density of 10 mA/cm(2)). Moreover, nanotube emitters are f ound to be able to deliver very high emission currents densities, with curr ent density routinely exceeding 1 A/cm(2). The low field operation of these carbon based emitters is attractive for display applications, while the hi gh current capability of nanotube emitters will enable a number of high pow er, high frequency devices. Further improvements over the emission uniformi ty hold the key for the realization of the potential of these carbon materi als in enabling practically useful cold cathode devices. (C) 2001 Elsevier Science Ltd. All rights reserved.