High-current-density field emitters based on arrays of carbon nanotube bundles

Abstract

We have developed high-current density field emission sources using arrays of multiwalled carbon nanotube bundles. The field emission behavior of a variety of lithographically patterned array geometries was investigated and the arrays of 1-μm and 2-μm-diameter nanotube bundles spaced 5μm apart (edge-to-edge spacing) were identified as the most optimum combination, routinely producing 1.5–1.8A∕cm2 at low electric fields of approximately 4V∕μm, rising to >6A∕cm2 at 20V∕μm over a ∼100-μm-diameter area. We have found that the field emission performance depends strongly on the bundle diameter and interbundle spacing and such arrays perform significantly better in field emission than ordered arrays of isolated nanotubes or dense, continuous mats of nanotubes previously reported in literature.