[en] Routine evaluation in X-ray photoelectron spectrometry comprises the standard evaluation steps 1) energy calibration 2) sample charging 3) spectrum processing 4) binding energy 5) layer thickness determination 6) quantitative analytics. This work shows the foundations and describes the development of computer codes for an on-site evaluation of measurement data with the help of an EPSON HX-20 computer. (Author, translated by G.Q.)

[en] The technique of quantitative Auger electron spectroscopy (AES) is central to modern surface analysis. Development, both in terms of new instrumental apparatus and the theoretical basis of Auger analysis, has been the subject of intense research. The work presented here investigates two of the current issues surrounding Auger electron spectroscopy and microscopy. The modelling of electron-solid interaction is reviewed, and investigations are carried out into the two well established computational techniques, transport theory and Monte Carlo simulation. The transport mean free path, λ_tr and the inelastic mean free path, λ_i describe electron transport in solids to the first order. Variations in these parameters with energy and atomic number are explored with a view to identifying trends and establishing the extent to which generalisations are valid. Although transport theory calculations have been shown to give an accurate representation of true electron behaviour, their application is largely limited to homogeneous materials. Monte Carlo modeling provides us with a more rigorous treatment of complex experimental conditions. A new Monte Carlo model is presented which allows extension of existing simulations to incorporate heterogeneous, multilayered samples. The design of integrated circuits is an extremely fast moving technology, with routine manufacture of nanometric feature sizes now becoming a reality. The second part of this work is devoted to the design of an angle resolved electron spectrometer with a very high resolution field emission electron probe. It is intended that high resolution analysis, coupled with the ability to resolve the azimuthal component of electron trajectories, will offer new insight into the surface features of ultra large scale integrated circuits. (author)

[en] With new and advanced analytical imaging methods emerging, the limits of physical analysis capabilities and furthermore of data acquisition quantities are constantly pushed, claiming high demands to the field of scientific data processing and visualisation. Physical analysis methods like Secondary Ion Mass Spectrometry (SIMS) or Auger Electron Spectroscopy (AES) and others are capable of delivering high-resolution multispectral two-dimensional and three-dimensional image data; usually this multispectral data is available in form of n separate image files with each showing one element or other singular aspect of the sample. There is high need for digital image processing methods enabling the analytical scientist, confronted with such amounts of data routinely, to get rapid insight into the composition of the sample examined, to filter the relevant data and to integrate the information of numerous separate multispectral images to get the complete picture. Sophisticated image processing methods like classification and fusion provide possible solution approaches to this challenge. Classification is a treatment by multivariate statistical means in order to extract analytical information. Image fusion on the other hand denotes a process where images obtained from various sensors or at different moments of time are combined together to provide a more complete picture of a scene or object under investigation. Both techniques are important for the task of information extraction and integration and often one technique depends on the other. Therefore overall aim of this thesis is to evaluate the possibilities of both techniques regarding the task of analytical image processing and to find solutions for the integration and condensation of multispectral analytical image data in order to facilitate the interpretation of the enormous amounts of data routinely acquired by modern physical analysis instruments. (author)

[en] L/sub III/ absorption measurements on a number of Ce-based systems together with their La and/or Pr isomorphs, show that the double peaked Ce-edge is not caused by final-state shakeup processes. Shakedown satellites were identified in the absorption edges of LaNi₅ and LaPd₃ by comparing to isomorphs of heavier rare earths. The observed smallness of final-state effects implies that the method of L/sub III/ absorption is both a convenient and reliable method for measuring the mixed-valent quotient. XPS and L/sub III/ absorption measurements were performed in a system where the electronic bandstructure can be varied continuously; namely Ce(Pd/sub 1-x/ T/sub x/)₃ where T = Rh or Ag. The shakedown intensities in the Ce 3d core levels were correlated with the mixed-valent behavior in this system. The two peaks in the 4f-derived photoemission in Ce-based systems have been a major puzzle in the understanding of these mixed valent effects. Several theories have tried to explain this phenomenon. Resonant valence-band photoelectron measurements were performed on the systems REAl₂, RERu₂ and REPd₃ (RE = La, Ce, Pr, and Nd). One observes the biomodal 4f spectrum in PrAl₂, PrPd₃, and NdPd₃, as well as in the Ce-isomorphs

No abstract available

[en] Please find the abstract and the fulltext under the available link.

[en] The research on bioactive materials, especially coatings, enables the production of resistant, nontoxic, biodegradable, and suitable antimicrobial surfaces for contact with food or humans. This project combined the effect of different types of chitosan in the manufacture of nanostructured films for antimicrobial coatings on textile substrates and silicon slides. Chitosan-based thin films were assembled using the layer-by-layer technique and the axial composition was accessed by X-ray photoelectron spectroscopy with depth profiling. Chitosan (Chi) samples possessing different average degree of acetylation (DA) and viscosity average molecular weight (Mv) were used in this study as well as two different polyanions, namely sulfonated polystyrene (SPS) and carboxymethyl cellulose (CMC). When chitosan, a positively charged polymer in aqueous acidic medium was combined with a strong polyanion (SPS), the total positive charge of chitosan, directly related to its average degree of deacetylation, was the key factor affecting the film formation and its structure. However, when a weak polyanion (CMC) was combined with chitosan, pH and viscosity average molecular weight of chitosan strongly affected film structure and composition. Following, we studied the molecular interdiffusion in thin films of CMC/Chi. There are few studies in the literature which explore the diffusion of a negatively charged polymer (in our case, the SPS) into a biopolymer thin film. This system illustrated in a simple way how chitosan interacts with different macromolecules (CMC and SPS). Higher binding energy values were observed for the Chi/SPS complex, as a result of the strong electrostatic interactions between the polymers. The CMC/Chi system is complemented with electrostatic interactions of weaker nature (i.e. hydrogen bounds). These changes in the binding energies were verified by the XPS high resolution spectra and provided a better understanding of LbL systems containing chitosan. Finally, we explored the spray LbL approach as a methodology to easy scale-up and capable of reducing the time required for the film build-up in comparison to the traditional dipping method. The variation of chitosan architecture, polyanion pair and pH shows that it is possible to molecularly control the chemical and structural properties of nanostructured coatings at the molecular level, thus opening up new possibilities to adapt them for the desired application, as shown by the antimicrobials tests. (author)

[en] The problem of interchangeability of surface analytical data is gaining increasing importance in multi-method surface analysis. As the VAMAS project and publications of M.P. Seah and the VAMAS Community show, a standardized data exchange format is necessary to allow an efficient exchange of data and control information obtained by different analytical tools. Computers used to control measurement instruments generally work with proprietary software under various operating systems. Only a standardized data exchange format can guarantee the independence of proprietary measurement systems without adaptation of existing software. Therefore, the software package MAXMIND based on public domain software products was developed. It is used for the transfer, archiving and editing of surface analytical data based on HDF. MAXMIND contains all available and necessary information on experimental conditions and all parameters specific for a number of analytical techniques such as Auger Electron Spectroscopy and Microscopy etc.. Additionally, all data concerning the state of the sample are summarized in the sample history, and the state of the instrument at the time of the measurement is summarized in the instrument description. One or more measurement series can be stored in a binary HDF-file comprising the 'subfiles' sample history, instrument description, description of the measurement series, measurement descriptions for each measurement and data files for all maps and spectra. In this way all data concerning a measurement series are combined in a single file in order to allow a well-founded evaluation of the data and an enhanced reproducibility of the experiment. (author)

[en] The construction of an angle resolving electron spectrometer for photoelectron spectroscopy is described. Energy spectra of polycristalline Tungsten, clean and covered, are presented. The angle dependence shows a maximum around αsub(A) = 20⁰. (G.Q.)

[en] In this work examples of the various aspects of photoelectron spectroscopy are given. The investigation was started with the development of an angle-resolved spectrometer so that the first chapters deal with angle-resolved ultra-violet photoelectron spectroscopy. To indicate the possibilities and pitfalls of the technique, in chapter II the theory is briefly reviewed. In chapter III the instrument is described. The system is based on the cylindrical mirror deflection analyzer, which is modified and improved for angle-resolved photoelectron spectroscopy. In combination with a position sensitive detector, a spectrometer is developed with which simultaneously several angle-resolved spectra can be recorded. In chapter IV, the results are reported of angle-integrated UPS experiments on dilute alloys. Using the improved energy resolution of the instrument the author was able to study the impurity states more accurately and shows that the photoemission technique has become an important tool in the study of impurities and the interactions involved. XPS and Auger results obtained from dilute alloys are presented in chapter V. It is shown that these systems are especially suited for the study of correlation effects and can provide interesting problems related to the satellite structure and the interaction of the impurity with the host. In chapter VI, the valence bands of ternary alloys are studied with UPS and compared to recent band structure calculation. The core level shifts are analyzed in a simple, thermodynamic scheme. (Auth.)