The influence of surface oxidation on prebreakdown electron emission processes

Electron spectroscopy and optical imaging techniques have been used to study changes in the current-voltage (I-V) characteristics of individual emission sites that result from the growth of 50- to 500-nm-thick layers of surface oxide. It has been established that while there is only a small effect on the I-V characteristic both the spectral shift and half-width exhibit a greatly enhanced field dependence. The fundamental implications of the results are very significant, since they can be discussed in terms of the most recently proposed nonmetallic models of the emission mechanism