Behaviors of field emitters under pulsed voltages

Abstract

In this paper we described our study of the behaviors of field emitters driven by square-wave voltages. We observed phenomena under pulsed voltages that generally do not manifest themselves under direct-current voltages. We interpreted these phenomena with the cathode and anode combined treated as equivalent to a resistor and a condenser in series connection. First, because of the delay caused by the charging process of the condenser, the waveform of the voltage across the cathode-anode gap was remarkably distorted. Second, the resistor led to considerable attenuation in field emission, which was clearly observable within each pulse and became more dramatic with increasing repetition frequency of the pulses. Furthermore, the field emission currents under direct-current voltages were lower than those under pulsed voltages. This disparity is attributed to rising resistance in the circuit with rising temperature. We also discussed the restrictions that the waveform distortion and current attenuation could impose on potential field emitter applications.