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Silver catalysed nanoscale silicon etching in water vapour
Křížek, Filip ; Pikna, Peter ; Fejfar, Antonín
N+-doped silicon substrates were etched by water vapour under the silver nanoparticles acting as a catalyst. Thin silver layer was deposited on two silicon wafers, where one of them was thermally annealed in nitrogen to create silver nanoparticles. Subsequently, both samples were annealed in water vapour and afterwards analysed by Scanning Electron Microscope. The images have shown that the annealed silver nanoparticles burrowed into the silicon substrate in the case of both samples. This new method of silicon etching introduces an alternative way of manufacturing nanohole arrays in silicon substrates.\n
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Structure and properties of DLC layers for industrial applications
Mates, Tomáš ; Ledinský, Martin ; Vetushka, Aliaksi ; Pikna, Peter ; Fejfar, Antonín ; Marek, A. ; Vyskočil, J. ; Erichsen, J. ; Dawah, P.
Diamond-like carbon (DLC) layers based on amorphous carbon are used for wide range of applications, mostly for mechanical protection of various industrial components. We examined DLC layers at micro- and nanoscale by two independent microscopic techniques: Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) with a good agreement. We compared DLC layers grown on steel substrate and Si wafer and found similarly structured clusters and a certain difference in the density of nucleation centres. The measurements of local mechanical properties by the AFM tip revealed that the Si wafer behaves as softer material compared to the growing DLC nanoclusters that also exhibit lower values in the map of the relative local friction coefficient. Finally, we observed changes in the Raman spectra of the DLC exposed to annealing at ambient conditions and found a gradual shift from the diamond phase to the graphite phase as a function of increasing temperature.
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Summary report of results of the contract research between FZU AV ČR, v.v. i. and HVM Plasma s.r.o. for 2016
Mates, Tomáš ; Fejfar, Antonín ; Ledinský, Martin ; Vetushka, Aliaksi ; Pikna, Peter ; Bauerová, Pavla
Samples of protective layers based on DLC (Diamond-like-Carbon) on different substrates (test bodies and real components) were studied by several diagnostic methods.\nRaman spectroscopy was used for the detection of bindings in order to specify the structural variations, surface modifications both for as-deposited samples and particularly for samples that underwent different stress tests.\nScanning Electron Microscope (SEM) was used to examine the surface structure of layers in different locations on the sample and to search suitable test spots for the subsequent analysis by the Atomic Force Microscope (AFM). AFM in special modes was employed to measure the maps local mechanical properties (friction, tip adhesion, energy dissipation, etc.).\nOn a selected sample, the cross-sectional structure of the sample was analysed by the Focussed Ion Beam (FIB) and the elemental composition in various thicknesses was documented by the Energy-dispersive X-ray Spectroscopy (EDS).\n
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Annealing of thin film polycrystalline silicon solar cells in water vapour
Pikna, Peter ; Fejfar, Antonín
Samples of thin film polycrystalline silicon solar cells prepared by the Company CSG Solar AG were treated in water vapour. Appearance of treated solar cells was very similar to samples etched in a solution of acids, which is commonly used to approach the bottom part of pn junction. No significant improvement of measured open-circuit voltage Voc was observed, but the etching effect of water vapour can determine the upper limit of temperature, pressure and treatment time for water vapour passivation. Novel approach for preparation of a depth profile to approach the bottom part of pn junction is proposed.
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Diversity as a value significant for Fantasy genre
Pikna, Peter ; Marek, Petr (advisor) ; Valak, Radim (referee)
The subject of Bachelor Thesis Diversity as value significant for Fantasy genre will be specific torrent of fantastical fiction, which is often entitled as escapical. In the first part, I will point out definition starting points of genre of Fantasy and its use in the film. In second part I will try to focus on value overlaps in more actual works of the genre (The Lord of the Rings, The Adventures of Baron Munchausen, Pan´s Labyrinth), which transcends frame of commercial-purpose quantity based production, degradating the genre into stereotype of big-budger spectacular for youths.
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