Field electron emission of diamondlike carbon films deposited by a laser ablation method

We have investigated field electron emission properties of diamondlike carbon films deposited by a laser ablation method. Emission properties of diamondlike carbon films show a strong correlation with surface roughness of the films which varies as a function of laser power densities. The threshold emission voltage of films turns out to be critically dependent on the surface morphology. Measurement of electrical resistivity shows that the density of states near the Fermi level is strongly localized. The major carrier transport occurs not by the activation to the conduction band but by hopping between the localized defect states near the Fermi level. The existence of localized defect bands in the intrinsic gap can also make it possible to emit electrons with a relatively small activation energy.