On the defect center electron energy loss structures from MgO surfaces

Abstract

Electron energy loss spectroscopy (EELS) was applied to surfaces of (1) clean MgO(100), (2) ultrathin (0.5 Å average thickness) Cu layers deposited on MgO(100) by an electron beam evaporation technique, and (3) a carbon-contaminated MgO(100). The surface-defect-related energy loss peak was ascribed to the presence of surface states arising from the V s − centers rather than from the F s + centers. The copper deposit is supposed to be trapped by the magnesium ion vacancies and bonded to the oxygen ligands as ions. The new electronic structures caused by the Cu deposit aie explained in terms of Cu impurity levels.