Erosion of the field emitter surface exposed to low-energy ions

Abstract

The radiation-induced erosion of the tungsten field emitter surface exposed to low-energy ions is studied by field ion microscopy and electron microscopy. During the bombardment, surface atoms are displaced to sites with lower coordination numbers and nanoasperities, generating a locally enhanced electric field, arise on the surface in a jump-like manner, which modifies the characteristics of the emitters. The field evaporation of the asperities produces cavities; hence, the erosion can be described in terms of blistering. Quasi-static surface erosion mechanisms are considered. It is shown that nanoblistering can be related to helium absorption in metal surface layers.