Field emission of single-walled carbon nanotubes welded on Ni substrate by ultrasonic nanowelding

Abstract

Ultrasonic nanowelding technology was used to improve the electron field emission characteristics of single-walled carbon nanotubes (SWNTs), which were deposited on the Ni substrate by electrophoretic deposition. The samples of sedimentary SWNT film were applied to ultrasonic nanowelding. Under the combined effect of high-frequency ultrasonic energy and clamping force, Ni was softened so that the SWNTs were easily wrapped up, where a reliable contact between SWNTs and Ni substrate was formed. The scanning electron microscopy results showed that SWNTs were embedded into the Ni substrate and acted as stable filed emitter. The welded cathode demonstrated the enhanced electron field emission characteristics of lower turn-on voltage, higher emission current density and stable emission current. These can be attributed to the raised tips of SWNTs under the action of small protrusions on the welding head, as well as the reduction of contact resistance after nanowelding. By using the large-area nanowelding technique, higher efficiency can be realized and the progress in manufacturing large-scale SWNT cathode can be accelerated. Show more