Multiwall and single-wall nanotubes were produced by carbon arc discharge in helium, and their structures were investigated by electron microscopy. Field emission from (1) as-grown multiwall nanotubes (MWNTs), (2) purified MWNTs and (3) purified single-wall nanotubes (SWNTs) was investigated by field emission microscopy. Of the three kinds of nanotubes studied, purified MWNTs whose tips are open provided the highest current at a fixed voltage. Although purified SWNTs provided the second highest current, SWNTs are not so robust as MWNTs against ion bombardment. As an application of nanotube field emitters, we manufactured cathode ray tube (CRT) lighting-elements by replacing conventional thermionic cathodes with nanotube field emitters. Stable electron emission, adequate luminance, and long life of the emitters were substantiated.
ASJC Scopus subject areas
- Chemical Engineering(all)