Growth and evaluation of nanostructured carbon films for triode field emitter application

To identify the deposition conditions that can minimize the nanotube density in the nanostructured carbon films without compromising the emission properties, we carried out a systematic investigation of the effect of deposition conditions on the emission properties and the structure of the nanostructured carbon films. Catalyst-layer thickness, methane concentration, deposition time, deposition pressure, and substrate temperature were the main deposition parameters we investigated. Within the parameter range for nanoparticle-dominant growth, substrate temperature and deposition time were the two factors that had the largest effect on the variation of the turn-on field. However, catalyst-layer thickness and methane concentration turned out to be the factors allowing the minimization of nanotube density with rather small concomitant variations of the turn-on field. A 50 h test showed that the emission stability of a nanoparticle film was better than that of a multiwall nanotube film with comparable emission characteristics. The feasibility of triode fabrication was verified by the successful deposition of a nanoparticle-film cathode of about 8 μm diameter using the conventional photolithography process. © 2003 American Vacuum Society.