On Electron-beam-induced Charging Effects in Cu- and Y-deposited LaAlO3 surfaces

Electron‐impact experiments on insulator and wide‐band‐gap semiconductor surfaces are disturbed by charging effects, particularly in cases of stoichiometric surfaces. We have studied the shift in kinetic energy of Auger electrons from 1×1 LaAlO₃(100) surfaces as a function of Cu coverage, time of electron‐beam bombardment, heat treatment, and−also for an Y deposited 1×1 LaAlO₃(100) surface−of primary beam energy. The energy shift is found to increase with metal coverage and with primary beam energy. It is suggested that at a particular energy the incident electrons result in a repulsive potential from which escaping Auger electrons gain kinetic energy, and that the initially deposited metal atoms may cause moving of electrons into valence‐band states created by hybridization of surface metal and oxygen states. For comparison, the energy shifts in nondeposited LaAlO₃(100), MgO(100), and SrTiO₃(100) were also investigated.