Comment on 'Design and circuit simulation of nanoscale vacuum channel transistors' by J. Xu, Y. Qin, Y. Shi, Y. Yang and X. Zhang, Nanoscale Adv. 2020, 2, 3582

TL;DR

This paper critiques a recent study on nanoscale vacuum channel transistors, highlighting inaccuracies in the theoretical emission current calculations and emphasizing the need for precise modeling to predict device performance accurately.

Contribution

It provides corrections to the existing theory of field electron emission in nanoscale vacuum transistors and advises against using simplified formulas that underestimate emission currents.

Findings

The simplified emission formula underestimates current density by a factor of around 300.

Accurate modeling is essential for predicting nanoscale vacuum transistor performance.

The paper clarifies theoretical inaccuracies in recent literature.

Abstract

These comments aim to correct some apparent weaknesses in the theory of field electron emission given in a recent paper about nanoscale vacuum channel transistors, and to improve the presentation of this theory. In particular, it is argued that a "simplified" formula stated in the paper should not be used, because this formula is known to under-predict emission current densities by a large factor (typically around 300 for an emitting surface with local work function 4.5 eV). Thus, the "simplified" formula may significantly under-predict the practical performance of a nanoscale vacuum channel transistor.