Self-texturing of nitrogenated amorphous carbon thin films for electron field emission

The electron field-emission process for nitrogenated amorphous carbon (a-C:H:N) thin films deposited using a magnetically confined hydrocarbon plasma is examined. The morphology of the films obtained using an atomic force microscope is compared to the field-emission properties. Beyond a chemical composition of 14 at. % nitrogen, the mirror smooth a-C:H:N films become self-texturing, and multiple “domelike” cathodes of nanometer scale are observed. The dimensions of these “domelike” cathodes varies with time, and after a 15 min deposition have dimensions of approximately 50 nm base diameter and 20 nm in height. When the electronic field emission of these textured films (N content 15 at. %) are measured, there is an enhancement in the emitted current density of ∼2 orders of magnitude at an electric field of 20 V/μm, in comparison to the untextured films with a nitrogen content of 11 at. %.