Statistical analysis of field electron emission from nanostructured carbon films

The field-emission properties of nanostructured carbon films (NSCFs), such as carbon nanotubes and carbon nanoparticles, were measured using a microtip and a large-area phosphor-screen anode. Except at small bias-voltage range, the current-versus-voltage curves measured with a large-area anode were fitted well to a simplified Fowler-Nordheim (FN) equation with a series-resistance effect. From the mapping of the turn-on field using a microtip anode, it was deduced that the field-enhancement factor β of NSCFs had an asymmetric distribution with a large-β tail. The asymmetric β distribution led to explanations of the slight curvature in FN plots at the low-voltage regime and of the exponential increase of emission-site densities dependent on the applied field.