A new perspective on the origin of prebreakdown electron emission processes

An account is presented of two probe techniques that have been used to locate and study the physical properties of individual electron emission sites on broad-area high-voltage electrodes. Details are given of the typical microgeometry and elemental composition of the particulate structures responsible for the emission, and the electron spectral and projection image characteristics of the emission process. These findings are discussed in terms of a recently proposed field-induced hot-electron emission (FIHEE) mechanism that involves a composite metal-insulator emission regime. Finally, the technological implications of these recent developments are considered.