Extension of the General Thermal Field Equation for nanosized emitters

TL;DR

This paper extends Jensen's general thermal field equation to nanosized emitters by incorporating curvature effects and high-temperature regimes, improving accuracy for modern nanometric electron sources.

Contribution

The authors develop a generalized GTF equation that accounts for emitter curvature and thermal effects, applicable to nanoscale emitters beyond planar assumptions.

Findings

Good agreement with numerical calculations for radii > 4nm

Current density predictions differ by up to a factor of 27 from standard GTF

Extended model applicable to modern sharp electron sources

Abstract

During the previous decade, K.L. Jensen et. al. developed a general analytical model that successfully describes electron emission from metals both in the field and thermionic regimes, as well as in the transition region. In that development, the standard image corrected triangular potential barrier was used. This barrier model is valid only for planar surfaces and therefore cannot be used in general for modern nanometric emitters. In a recent publication the authors showed that the standard Fowler-Nordheim theory can be generalized for highly curved emitters if a quadratic term is included to the potential model. In this paper we extend this generalization for high temperatures and include both the thermal and intermediate regimes. This is achieved by applying the general method developed by Jensen to the quadratic barrier model of our previous publication. We obtain results that are in good agreement with fully numerical calculations for radii $R>4nm$, while our calculated current density differs by a factor up to 27 from the one predicted by the Jensen's standard General-Thermal-Field (GTF) equation. Our extended GTF equation has application to modern sharp electron sources, beam simulation models and vacuum breakdown theory.