Surface microstructure of MgO deposited on SiO2 by analysis of plasmon excitations in photoemission experiments

The growth mechanism of increasing amounts of MgO deposited by evaporation on the surface of SiO2 is investigated by factor analysis of the plasmon structure behind the Mg1s photoelectron peak and by Tougaard background analysis of the same peak. It is shown that MgO grows in the form of islands on the SiO2 surface. The height of these islands has been related to the intensity of the surface and the bulk plasmons at each stage of the deposition experiment. From these results, an alternative method, based on the analysis of the plasmon structure observed behind X-ray photoelectron peaks, is proposed for the characterisation of the microstructure in this type of systems.