Fabrication and characterization of high-current-density carbon-nanotube cold cathodes

In this paper, we report a recent experimental observation of high field-emission current density (6.5 A/cm2) from carbon nanotube emitters. Carbon nanotubes are grown on Ni catalyst coated on Si substrates using chemical vapor deposition of C2H2 gas at 700 °C. Our research shows that it is beneficial for getting the high-current density in our experiment that Au film was deposited onto Si substrate before evaporating a Ni catalyst dot onto the substrate. We compared the field emission characteristics of CNTs cathodes grown on the Ni films with different thickness of 50, 70, 100 nm. The thickness of the Ni film is very important for the growth of CNTs, which will affect the field emission properties very much. The Fowler-Nordheim plot showed a good linear fit, indicating that the emission current of carbon nanotubes follows Fowler-Nordheim behavior. The calculated field enhancement factor was 2370.