Transit-time oscillations in nanoscale vacuum diode with a pure resistive load

TL;DR

This paper investigates high-frequency current oscillations in a nanoscale vacuum diode caused by external resistor loading, combining molecular dynamics simulations and analytical modeling to understand the phenomenon.

Contribution

It introduces a simple mechanism explaining persistent THz oscillations in nanoscale vacuum diodes due to beam loading effects, supported by simulations and analytical models.

Findings

Oscillations occur in the THz frequency range.

Amplitude and frequency depend on diode operating parameters.

The analytical model agrees well with simulations.

Abstract

We examine the Ramo current in a nanoscale planar vacuum diode undergoing field emission in the presence of a DC voltage supply and an external resistor. We describe a simple mechanism for generating persistent current oscillations in the diode due to the voltage drop across the external resistor (beam loading) which reduces the total field and inhibits the emission. The amplitude and the frequency, which is in the THz domain, depend on the operating parameters of the diode. Molecular dynamics simulations are used to find the characteristics and physical basis of the mechanism, and a simple analytical model is presented, in good agreement with the simulation.