Fowler-Nordheim Plot Analysis: a Progress Report

TL;DR

This paper reviews and advances the methodology for analyzing Fowler-Nordheim plots in cold field electron emission, emphasizing slope interpretation and addressing series resistance effects for more accurate characterization.

Contribution

It introduces a systematic approach to FN-plot analysis, focusing on slope interpretation and methodology for data with series resistance, enhancing accuracy in characterizing electron emitters.

Findings

FN-plot slope interpretation is more straightforward and experimentally relevant.

Raw current-voltage data should be used directly for analysis, especially with series resistance.

Formulae are provided for extracting field-enhancement factors from measurements.

Abstract

The commonest method of characterizing a cold field electron emitter is to measure its current-voltage characteristics, and the commonest method of analysing these characteristics is by means of a Fowler-Nordheim (FN) plot. This tutorial/review-type paper outlines a more systematic method of setting out the Fowler-Nordheim-type theory of cold field electron emission, and brings together and summarises the current state of work by the authors on developing the theory and methodology of FN plot analysis. This has turned out to be far more complicated than originally expected. Emphasis is placed in this paper on: (a) the interpretation of FN-plot slopes, which is currently both easier and of more experimental interest than the analysis of FN-plot intercepts; and (b) preliminary explorations into developing methodology for interpreting current-voltage characteristics when there is series resistance in the conduction path from the high-voltage generator to the emitter's emitting regions. This work reinforces our view that FN-plot analysis is best carried out on the raw measured current-voltage data, without pre-conversion into another data format, particularly if series resistance is present in the measuring circuit. Relevant formulae are given for extracting field-enhancement-factor values from such an analysis.