Electric field emission characteristics of a triode-structured metallic edge emitter from geometric conditions

Abstract

Spindt-tip type cold electron emission has potential in various applications; however, it has a limited current capacity that prevents the emitters from being used for higher current sources, and the fabrication of the emitters is not easy. In this study, we investigate the electric field emission characteristics of a triode-structured metallic edge emitter from geometric conditions. We perform a systematic simulation based on Fowler-Nordheim theory to analyze the feasibility of using the proposed emitter. The dependences of the emission current, electron transmittance, and region of the triode mode on specific geometrical parameters, including the anode-gate vertical distance, gate-cathode vertical distance, gate-cathode horizontal distance, anode voltage, and gate voltage, are analyzed. The results show that the electric field for a narrow gate-cathode vertical distance is superior to the electric field of the gate electrode for a narrow gate-cathode horizontal distance, while the electric field for a wide gate-cathode vertical gap is more dominant than the electric field of the anode electrode for a wide gate-cathode horizontal gap. Moreover, the electron transmittance gradually increases with a low gate voltage, wide anode-gate vertical distance, and high anode voltage, and the region of the triode mode also increases with a high gate voltage, wide anode-gate vertical distance, and low anode voltage. Consequently, our results appear to be effective for an optimization in an experiment and are expected to improve present electric field emission techniques.