Comparing the performance of Fowler-Nordheim plots and Murphy-Good plots

Field electron emission studies normally use Fowler-Nordheim (FN) plots to analyze measured current-voltage characteristics. More precise extraction of emitter characterization parameters could perhaps be achieved if the data were plotted as a so-called “Murphy-Good (MG) plot”. Unlike a Fowler-Nordheim plot, which is theoretically predicted to be slightly curved, a Murphy-Good plot is predicted to be “almost exactly” straight. This presentation gives relevant theoretical formulas, and reports a comparison between these two plot types, based on the use of simulated data. It is confirmed that a MG plot can be used to apply an orthodoxy test. And it is illustrated that a MG plot gives results for extracted characterization parameters that are more precise than those extracted from a FN plot.