Relationship between device characteristics and field-emission mechanisms in planar electron tubes

Planar field-emission electron tubes exhibit an exponential rise in anode current with increasing anode voltage and lack inherent output saturation, leading to low output resistance and weak load-driving capacity, which is a key bottleneck holding back their real-world deployment. To address this issue, this paper constructs a field-emission testing platform capable of modulating cathode electron density to modulate the cathode carrier supply and investigates the field-emission characteristics of planar electron tubes with single-crystal silicon and polycrystalline silicon cathodes. The results verify a strong dependence of semiconductor emission performance on electron density: when operated in the electron-supply-limited regime, insufficient electron supply clamps the anode current into a saturation-like output which is similar to the macroscopic output characteristics of MOSFETs, delivering markedly improved output impedance and load-driving capability. More importantly, this work establishes an experimental link between gate-controlled cathode carrier supply, the field-emission operating regime, and circuit performance in planar electron tubes. By incorporating semiconductor field-emission regulation principles into circuit-level analysis and validating the findings against a physical test circuit, higher voltage gain is achieved when the device operates in the electron-supply-limited regime. This regime can be accessed at lower anode voltages by adopting a minimal anode–cathode gap and reduced cathode electron density. This characterization approach offers a fresh experimental avenue for exploring semiconductor field-emission mechanisms and carries both fundamental theoretical value and practical engineering relevance for advancing emerging vacuum microelectronic devices.