[en] The exciting beam of an Auger electron spectrometer has been used to monitor the oxidation of silicon single crystals at room temperature and very low pressures of oxygen (approx. 10^-7 Torr). This process allows us to build ultra-thin layers of silica on silicon (down to 30 A) but it is mostly used to investigate the mechanisms of the initial stages of oxidation. Auger spectra recorded continuously during the oxidation process provide information on (1) the nature of the silicon-oxygen chemical bonds which are interpreted through fine structure in the Auger peak, and (2) the kinetics of oxide formation which are deduced from curves of Auger signal versus time. An account is given of the contribution of these Auger studies to the description of the intermediate oxide layer during the reaction between silicon and oxygen and the influence of surface structural disorder, induced mainly by argon-ion bombardment, is discussed in terms of reactivity and oxide coverage. (author)

[en] Auger electron spectroscopy (A.E.S.) allows to characterize the atoms lying at surfaces of amorphous and crystalline materials and to investigate their chemical bond. In the case of single crystals it is generally associated with LEED which gives information on the surface structure. After having recalled some principles about radiationless deexcitation of atoms and the related Auger transitions, the problems of interpretation of energy spectra in the case of a single atom and their of an atom bound to neighbours either of the same kind or of a different one, are discussed. Some applications of A.E.S. as an analytical method are finally described

[en] Photoemission data are presented for the Pt/InP (110) interface. The ''as deposited'' 1-6 ML Pt/InP (110) interface is heterogeneous: a reacted Pt-P phase forms on patches of surface and grows in depth forming icebergs, while other regions of the interface do not react with Pt. The Cooper minimum photoemission method, using synchrotron radiation as the photon source, is employed to discuss the bounding structure of the Pt-P icebergs

[en] Surface L_III absorption and UV photoemission experiments are reported for the characterization of the interface between deposited Yb (0.4-10 nm) and a Pd (111) surface. A schematic description of interface formation is proposed combining the two types of experiment and taking advantage of Yb valence sensitivity to the local environment

[en] Photoemission and photoabsorption experiments have been carried out on the 2p level in cerium nitride. Whereas strong final-state satellites are observed on the 2p-XPS spectrum indicating an important mixture of 4f¹ and 4f⁰ configurations in the ground state, the L_III edge spectrum only exhibits a white line that is usually interpreted as the signature of a trivalent configuration. This apparent contradiction between the two spectroscopies indicates that the phenomenological approach of Ce-L_III edge is inappropriate for CeN. We discuss these absorption experiments in the framework of a Gunnarsson-Schoenhammer model modified to include the interaction between the photoelectron and the system. We show that the unusual L_III edge observed in cerium nitride results from the peculiar band structure encountered in this compound