Electron-field-emission properties have been investigated systematically for carbon nanotubes (CNTs) fabricated on a metal tip. With a vacuum gap of 0.7mm, the threshold field is as low as 0.7V/μm and the current density approaches 10mA/cm2 at an electronic field of 1.0V/μm. The emission current is quite stable with very low fluctuation. The emission behavior is in excellent agreement with Fowler-Nordheim theory and no current saturation is found even with an emission current reaching 1A/cm2. A universal relationship 1/β=d2/d+1/β0 between the field amplification factor β and the vacuum gap d is developed within a two-region field-emission model. This relationship provides the basis for a microscopic understanding of CNT emitters and is applicable to other systems as well.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)