Field Emission from a New Form of Thin Film Amorphous Carbon Having Nanoparticle Inclusions and Carbon Nanotubes

Field emission results from a new form of carbon thin film are reported. The films contain carbon nanoparticles (nanotubes, "onions" and "eggs") within an amorphous carbon matrix and are deposited using a carbon arc with a localized high-pressure gas region of He of N₂. The films formed in an N₂ environment have a nitrogenated amorphous carbon (a-C:N) matrix and show clear Fowler-Nordheim-type metallic field emission characteristics. The field emission is very similar to that obtained from pure, randomly oriented multi-wall and single-wall nanotube films. It is proposed that the new a-C:N/nanoparticle films emit electrons through conducting channels formed in the film, subsurface field emission into the a-C:N matrix and hot electron surmounting of the surface potential barrier between the a-C:N and vacuum. Field enhancement factors of over 1000 are calculated for the thin film emitters when the nanoparticle work function is taken as 5 eV. This class of a-C:N/ nanoparticle film has the potential to be a thin film equivalent to carbon nanotubes in terms of field emission.