[en] Auger first experiences in 1923 and thesis in 1926 on photoelectrons with a Wilson chamber are shortly presented. The two related techniques, Siegbahn XPS (X-ray Photoelectron Analysis) and Auger AES (Auger Electron Spectroscopy), are compared for surfaces analysis with advantages and disadvantages. (A.B.). 13 refs., 3 figs

[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

No abstract available

[en] CdS 'Q-state' particles, with average diameters varying from 2 nm to 10 nm, grown in arachidic acid Langmuir-Blodgett (LB) films, deposited onto optically transparent glass electrodes (OTES), were exposed to H₂ Se(g) to form the corresponding Q-state Cd S_x Se_(1-x) particles. Those particles are considered to be made up of a core of CdS and coated with a monolayer of Cd Se. Q-state Cd S-x Se_(1-x) particle formation was verified by X-ray photoelectron spectroscopy (XPS) and by monitoring a red shift in the UV-visible absorbance spectra relative to that of Cds. XPS results on 5 nm diameter CdS particles that had been grown in an LB film and then extensively exposed to H₂ S (g) revealed a stable average composition of Cd S₀.₄ Se₀₆. A study of the photoelectrochemical behaviour of these systems was conducted through current the open-circuit voltage and a marked increase in the short-circuit current was observed when LB films with Q-state CdS particles were exposed to H₂ Se(g). (author)

[en] After a survey of the general principles of Auger electron spectroscopy, experimental techniques and their limitations are given. Application to thin layers and light elements detection is a complement of other surace analysis methods

[en] Considerable recent theoretical work has shown that core--valence--valence Auger lineshape analysis may often be successfully made in terms of the molecular orbital structure of the molecule or the band structure of the solid. This approach assumes a priori that the final state hole motion is uncorrelated. Limitations to this approach include the highly correlated final states observed in ionic and narrow band solids (as Cu). Complications to this approach include the initial state valence screening of the core hole which affects the Auger decay probabilities. However, much useful information about the local density of states (local chemical environment) may be extracted in covalent and metallic materials. Examples from molecular (CH₄, C₂H₄, C₂H₆, and C₃H₈) and solid state (Cu and Be) spectra are presented and the state of our understanding of lineshape analysis is summarized

[en] Short communication. 2 refs., 1 tab

[en] Thanks to funding from FAPESP we will be installing in the beginning of 1997 a work station for electron spectroscopy designed for the study of clean solid surfaces and the modification of these surfaces by deposition in situ of ultra thin metallic films. The main analytical tool will be a high resolution hemispherical analyzer made by VSW-Omicrom (EA 125 HR) which is capable of better than 5 meV resolution and high transmission due to its five channeltron multi detection system. The system will also have a Rear View LEED Optics for single crystal studies. The system will be housed in a 16'' cylindrical chamber with mu metal magnetic shielding having two levels for analysis. The upper level will contain instruments for technique which do not require photons such as LEED and sample cleaning. The lower level will have the electron analyzer, conventional X-ray source (Al/Mg), electron gun for Auger, e-beam evaporators for thin film deposition and ports for the future addition of different detectors. We will have a manipulator with 5 degrees of freedom (thre translation and two rotational) and sample heating and LN cooling. Finally we will have a fast entry/preparation chamber. The pumping system will have a combination of turbomolecular and ion pumps for the main chamber and a turbo for the fast entr/prep chamber. The system will be used initially for the study of surface alloys by XPS and Photoelectron Diffraction but as soon as it is properly characterized it will be open for collaborations with other groups interested in using its capabilities. (author)

[en] We calculate electron-energy-loss spectra for self-similar systems of polarizable spheres using a previously developed theory for the electron-energy loss of a system of identical spheres. We do this by means of a recursive procedure and an effective 'local' dielectric function, which contains, implicitly, the effects of spatial nonlocality due to correlations and multipolar interactions among the spheres, as well as some characteristics of the experimental setup. We also apply the procedure to systems of spheres with a continuum distribution of sizes. Finally, we propose a simple nonlocal generalization of Bruggeman's differential effective medium theory

[en] Atomic concentration profiles are produced by ion implantation of nitrogen into silicon targets at various ion energies and doses (150 and 250 keV; 0.25 to 1 x 10¹⁸ N⁺ cm^-2). The depth profiles obtained by AES/sputtering measurements are compared with those calculated by Monte Carlo simulation of the ion implantation process. The agreement is good if the calculation includes the main effects which influence the implantation. e.g. sputter erosion of the surface, cascade mixing, and change of atomic concentration of the target during implantation. (Author)