Quantum-confined planar vacuum triode

We propose a quantum-confined planar vacuum triode, a mesoscopic vacuum device in which electron transport is controlled by quantum confinement in a nanoscale vacuum channel. Unlike conventional vacuum triodes based on electrostatic electron deflection, the proposed device operates through competition between longitudinal tunneling to the anode and transverse tunneling to the gate. A gate-controlled redistribution of the electron flux between these channels leads to a sharp suppression of the output current. The quantum transport model predicts terahertz-range operation with cutoff frequencies of 0.5–5 THz and reduced shot noise due to quantum partitioning. The device operates over a wide temperature range, with cryogenic conditions offering optimal switching steepness and noise performance for high-speed electronics, quantum sensing, and single-electron applications.