Comparison of Cu-MgO Interfaces Studied by EXES and XPS

With the aim of studying the physicochemical interactions in metal-ceramic interfaces, we have investigated the Cu-MgO system. Two kinds of interfaces prepared at room temperature have been studied: interfaces during their formation (studied by X-ray photoelectron and Auger spectroscopies — XPS, AES) and buried interfaces (studied by electron-induced X-ray emission spectroscopy — EXES). Auger parameter results reveal a Cu(I) state for copper and point out, by comparison with the Cu-NaCl interface, that the oxidation comes from an interaction at the interface. EXES studies of the oxygen and copper valence densities of states evidence that the same kind of interaction exists at the interface between thick films of Cu and MgO and it does not exceed one interatomic distance.