[en] This paper is an attempt to understand how Polycaprolactone-b-Polymethyl Methacrylate diblocks (PCL-b-PMMA) are organized in a confined geometry such as nanometric thin films spin coated on gold coated substrates. Polarization-Modulation Infrared Reflection Absorption Spectroscopy (PM-IRRAS), employed to characterize PCL-b-PMMA thin films, allowed us to suggest an adsorption model of PCL-b-PMMA diblock copolymers in which PCL chains are almost perpendicular to the substrate plane, while PMMA blocks seem to be flattened at the surface. These results were also supported by Atomic Force Microscopy (AFM) that was extremely useful for the comprehension of PCL-b-PMMA diblocks behavior when adsorbed as thin films. The combination of the experimental observations offered us the possibility to propose a model of chain folding in the PCL-b-PMMA diblock copolymers after adsorption on chemically inert substrates. (author)

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[en] Anodically grown Ta₂O₅ layers with thicknesses d between 15 and 300 nm on polycrystalline tantalum substrates were investigated by sputter depth profiling in combination with Auger electron spectroscopy (AES). Normally incident Ne⁺, Ar⁺ and Xe⁺ ions of energy 200 eV-3 keV were used for the sputter removal. A high depth resolution of less than one atomic distance was obtained by appropriate rastering of the ion beam and by carefully positioning the electron beam in the centre of the rastered area. (Auth.)

[en] The ∼60 nm wide and ∼2 μm long TiO₂ nanotubes were obtained by anodization of Ti films sputtered on F-doped tin oxide glass. For N-doping the samples were annealed in ammonia atmosphere. The effect of pre- and post-annealing in air on the nature and amount of incorporated N was studied by X-ray photoelectron spectroscopy. By measuring the absorption spectra of the obtained samples and interpreting the corresponding Tauc plots it was shown that the sample annealed just in ammonia showed the highest visible light absorption even after sputtering cleaning and a decrease of N amount from 3.8% to 1%. Pre and/or post annealing in air led to smaller amount of incorporated N, that caused less pronounced absorption enhancement and smaller band gap narrowing compared to the sample annealed only in ammonia. By fitting of N₁ s line, the contribution that was assigned to substitutional N was detected only in the samples that did not sustained post-annealing. The study showed that post-annealing in air might lead to partial conversion of N atoms in TiO₂ to oxidized nitrogen species that are easily removed with sputtering. It is also possible that substitutional nitrogen was suppressed by oxygen from air to move to interstitial site. Weakly bonded NOx surface species, which are cleaned away by sputtering, can be removed by post-annealing in air. Those surface species could act as sensitizers and when their amounts are reduced, the core absorption properties, as a result of interstitial incorporation of N in TiO₂ structure, were revealed. Much lower visible light sensitization was achieved in the case of pre-annealed sample in comparison to sample without pre-annealing, regardless the same quantity and type of incorporated nitrogen.

[en] We report on first-principles calculations of the properties of the MoSe₂/Mo(110) interface. Due to mismatch between the lattice parameters of the two structures, different patterns can form at the interface. We have studied the formation energy and the band alignment of six patterns for the MoSe₂ (0001)/Mo(110) interface and one pattern for the MoSe₂ (1120)/Mo(110) interface. The MoSe₂ (1120)/Mo(110) interface is more stable than the MoSe₂ (0001)/Mo(110) interface and in contrast to MoSe₂ (0001)/Mo(110), no Schottky barrier forms at MoSe₂ (1120)/Mo(110). Doping with Na modifies the band alignment at the interfaces. The Schottky barrier height decreases, provided that a Na atom occupies a Mo atom site in MoSe₂ films. (authors)

[en] Different diffraction patterns measured above and below the critical angle for total reflection were recorded on a Gd doped ceria layer deposited on a Si(100) substrate in asymmetric coplanar diffraction conditions. From the analysis of diffraction patterns, it was possible to point out peculiar optical aberrations responsible for the shifts and the broadenings of Bragg peaks induced by this setup. Corrections for all these aberrations were implanted in a Rietveld programme. Using these corrections, it becomes possible to follow the evolution of the structure (chemical composition, phases) and the microstructure (strain field, micro strain due to heterogeneities between grains, size of coherent diffracting domains) versus the depth on thin films. (authors)

No abstract available

[en] Si-C films approximately 1 μm thick were synthesized on heated (830⁰C) Si(100) wafers using dual magnetron source sputter deposition and elemental carbon and silicon targets. Films of different compositions were analyzed for homogeneity, composition and impurities by sputter profiling in combination with Auger electron spectroscopy. Auger line shape analysis was used to detect differences in the bulk and surface chemistry of carbon and silicon. (Auth.)

No abstract available

No abstract available