ALKALI-HALIDE LAYERS ON W(110) - ELECTRON-STIMULATED DESORPTION OF IONS, STRUCTURE, AND COMPOSITION

Electron-bombardment-induced alkali- and halogen-ion desorption from NaCl, KCl, KBr, KI, and CsI layers on W(110) are studied as a function of layer thickness from zero to several monolayers. The ion-energy distributions change with coverage which indicates the action of several desorption processes. The energy dependence of the ion yields shows that the primary step of these processes is the Knotek-Feibelman mechanism. Postemission neutralization is found to play an important role. The evolution of the ion yields with coverage contributes significantly to the understanding of the initial growth of the layers, which is obtained mainly from Auger electron spectroscopy and work-function-change measurements.