Focusing Characteristics of Double-Gated Field-Emitter Arrays with a Lower Height of the Focusing Electrode

In order to control electric field relaxation at the tips of practical emitters, we found that volcano-structured double-gated field emitter arrays (VDG-FEAs) could be improved by placing the focusing electrode 470 nm below the electron extraction electrode. We demonstrated that this approach enables excellent endurance in terms of focusing potential, and confirmed its superior focusing characteristics. Even under strong focusing operation at a focusing electrode voltage of 5 V, this VDG-FEA maintained the anode current of 1.9 ?A, which was 5 times larger than that of the VDG-FEA with the same height of the focusing and electron extraction electrodes.