Nitrogen containing hydrogenated amorphous carbon for thin-film field emission cathodes

Field emission measurements using 0.3 μm thick nitrogen containing hydrogenated amorphous carbon films (a-C:H:N) on n++-Si cathodes are reported. Onset emission fields as low as 4 V μm−1 have been obtained using a flat plate anode configuration. Uniform emission is observed over the entire cathode area at current densities below 7×10−2 mA cm−2. At higher current density preferential emission from spots is observed. The spot emission is imaged using the ITO coated plate anode. A model based on the a-C:H:N acting as a space charge interlayer on the n++-Si is proposed to explain the emission at low electric fields.