Field emission characteristics of single and double-walled carbon nanotubes attached on the AFM tip using a dielectrophoresis method

Abstract

The bundles of single walled carbon nanotubes(SWCNTs) and double walled carbon nanotubes (DWCNTs), which were synthesized by a hydrogen arc discharge, were attached on the tip of AFM probe using a dielectrophoresis method in order to fabricate the SWCNT or the DWCNT emitter. To dielectrophoretically attach the SWCNT or the DWCNT bundle on the AFM tip, alternating bias between the AFM tip and the planar counter electrode was applied to a solution of CNT bundles. After attaching a bundle of CNTs on the AFM tip, field emission of an individual SWCNT or DWCNT bundle was measured and investigated. The Fowler-Nordheim plot of the measured field emission current could be fitted to 2 lines with dierent slopes, which are corresponding to two kinds of CNT groups with dierent field enhancement factors. The field enhancement factor of the SWCNT emitter was nearly the same as that of the DWCNT emitter, but the density of emission site of the SWCNT emitter was higher than that of the DWCNT emitter. This result indicates that the emission current per an operating SWCNT emitter should be smaller than that of the DWCNT emitter when the same emission current is extracted from the SWCNT and DWCNT emitters. It reveals that the lifetime of the SWCNT emitter fabricated on the AFM tip may be expected to be longer than that of the DWCNT emitter. This expected behavior was observed experimentally from the lifetime measurement result of planar field emitters fabricated using SWCNTs and DWCNTs.