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DDC: 530 × Subject: X-ray photoelectron spectroscopy ×

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    XPS investigations of MOCVD tin oxide thin layers on Si nanowires array
    (Amsterdam : Elsevier, 2018) Turishchev, S.Yu.; Chuvenkova, Olga; Parinova, V.E.; Koyuda, D.A.; Chumakov, Ratibor G.; Presselt, Martin; Schleusener, Alexander; Sivakov, Vladimir
    Tin oxide thin layers were grown by metal-organic chemical vapor deposition technique on the top-down nanostructured silicon nanowires array obtained by metal-assisted wet-chemical technique from single crystalline silicon wafers. The composition of the formed layers were studied by high-resolution X-ray photoelectron spectroscopy of tin (Sn 3d) and oxygen (O 1 s) atoms core levels. The ion beam etching was applied to study the layers depth composition profiles. The composition studies of grown tin oxide layers is shown that the surface of layers contains tin dioxide, but the deeper part contains intermediate tin dioxide and metallic tin phases.
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    On the possibility of PhotoEmission Electron Microscopy for E. coli advanced studies
    (Amsterdam [u.a.] : Elsevier, 2020) Turishchev, S.Yu.; Marchenko, D.; Sivakov, V.; Belikov, E.A.; Chuvenkova, O.A.; Parinova, E.V.; Koyuda, D.A.; Chumakov, R.G.; Lebedev, A.M.; Kulikova, T.V.; Berezhnoy, A.A.; Valiakhmedova, I.V.; Praslova, N.V.; Preobrazhenskaya, E.V.; Antipov, S.S.
    The novel approach was proposed for detailed high-resolution studies of morphology and physico-chemical properties concomitantly at one measurement spot of E. coli bacterial cells culture immobilized onto silicon wafer surface in UHV conditions applying PhotoEmission Electron Microscopy under Hg lamp irradiation. For the E. coli characterization scanning electron microscopy (electron beam) and X-ray photoelectron spectroscopy (X-ray tube radiation) were applied prior to PhotoEmission Electron Microscopy measurements. In spite of irradiation doses collected for the cell arrays we were successful in detection of high-resolution images even of single E. coli bacterium by PhotoEmission Electron Microscopy technique followed by detailed high-resolution morphology studies by scanning electron microscopy. These results revealed widespread stability of the E. coli membranes shape after the significant number of applied characterization techniques. © 2019 The Authors
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    Chemical in-depth analysis of (Ca/Sr)F2 core–shell like nanoparticles by X-ray photoelectron spectroscopy with tunable excitation energy
    (Chichester [u.a.] : Wiley, 2021) Müller, Anja; Krahl, Thoralf; Radnik, Jörg; Wagner, Andreas; Kreyenschulte, Carsten; Werner, Wolfgang S.M.; Ritter, Benjamin; Kemnitz, Erhard; Unger, Wolfgang E.S.
    The fluorolytic sol–gel synthesis is applied with the intention to obtain two different types of core–shell nanoparticles, namely, SrF2–CaF2 and CaF2–SrF2. In two separate fluorination steps for core and shell formation, the corresponding metal lactates are reacted with anhydrous HF in ethylene glycol. Scanning transmission electron microscopy (STEM) and dynamic light scattering (DLS) confirm the formation of particles with mean dimensions between 6.4 and 11.5 nm. The overall chemical composition of the particles during the different reaction steps is monitored by quantitative Al Kα excitation X-ray photoelectron spectroscopy (XPS). Here, the formation of stoichiometric metal fluorides (MF2) is confirmed, both for the core and the final core–shell particles. Furthermore, an in-depth analysis by synchrotron radiation XPS (SR-XPS) with tunable excitation energy is performed to confirm the core–shell character of the nanoparticles. Additionally, Ca2p/Sr3d XPS intensity ratio in-depth profiles are simulated using the software Simulation of Electron Spectra for Surface Analysis (SESSA). In principle, core–shell like particle morphologies are formed but without a sharp interface between calcium and strontium containing phases. Surprisingly, the in-depth chemical distribution of the two types of nanoparticles is equal within the error of the experiment. Both comprise a SrF2-rich core domain and CaF2-rich shell domain with an intermixing zone between them. Consequently, the internal morphology of the final nanoparticles seems to be independent from the synthesis chronology.