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.

Terahertz applications of carbon nanotubes

“…One of the latest trends in THz technology [2] is to use carbon nanotubes -cylindrical molecules with nanometer diameter and micrometer length [3-5] -as building blocks of novel high-frequency devices. There are several promising proposals of using carbon nanotubes for THz applications including a nanoklystron utilizing extremely efficient high-field electron emission from nanotubes [2,6,7], devices based on negative differential conductivity in large-diameter semiconducting nanotubes [8,9], high-frequency resonant-tunneling diodes [10] and Schottky diodes [11][12][13][14] [20].…”

Efficient field emission from structured gold nanowire cathodes

“…The applicability of CNT cathodes in vacuum nanoelectronic devices, however, is still limited by the homogeneity, stability and controllability of the current in defined FE arrays [3][4][5]. Metal nanowires (NW) with high aspect ratio (AR) and high conductivity fabricated by the ion-track template technique [6,7] provide an interesting alternative.…”

Carbon Nanotube Electron Sources: From Electron Beams to Energy Conversion and Optophononics

“…Field-emission was among the first applications considered for carbon nanotubes, and pioneering studies go back to the early days of nanotube research [72][73][74]. Field-emission experiments have involved single-walled [75][76][77], double-walled [78] and multiwalled [79][80][81][82][83][84][85][86] carbon nanotubes and included devices made of individual nanotubes or collections of nanotubes, sometimes mixed with other materials. A large number of the studies have primarily focused on current-voltage characteristics, while others have also investigated the emission spots using field-emission microscopy (Figures 4(b) and 4(c)) [87,88].…”