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Interakce umělé fotosyntetické antény s akceptory elektronů
Dostál, Jakub ; Pšenčík, Jakub (advisor) ; Fejfar, Antonín (referee)
The use of bacteriochlorophyll aggregates as a sensitizer for dye-sensitized cell has been studied in this work. Bacteriochlorophyll aggregates exhibit unique light-harvesting properties combining high optical density, long-term stability and exciton delocalization. Preparation of the GrÄatzel type photovoltaic cells has been successfully managed during this research. The cells were sensitized by bacteriochlorophyll c both in monomeric and aggregated form, and were characterized by measuring photoinduced current, voltage and other properties. As a part of this work a theoretical model of reversible two-level photovoltaic cell was derived from the thermodynamic principles. Predictions of this model are compared with experimental data and with published results.
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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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Application of Interferometry in VT UHV SPM
Šulc, Dalibor ; Klapetek, Petr (referee) ; Fejfar, Antonín (referee) ; Spousta, Jiří (advisor)
The thesis is aimed at the development of Scanning Probe Microscopes (SPM). It describes design and development of modular controll electronics to be applied eectively on more microscopes SPM. Control electronics consist of stabilized power source, high–voltage amplier and probe signal amplier. The open–source project GXSM has been introduced. It contains a logic control unit which controls scanning, acquiring data and feedback control. GXSM provides a graphical user interface based on linux operation system. Second part of the thesis is aimed at design and development of interferometric deection sensing system for SPM cantilevers and applications at SPM in general. Designed interferometer has been assembled and tested. It can clearly distinguish a signal of amplitude 2 nm. At the end of the thesis the design of interferometric system implementation is presented.
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Development of Instrumental Equipment for the Characterization of Nanostructures
Nováček, Zdeněk ; Ošťádal, Ivan (referee) ; Fejfar, Antonín (referee) ; Šikola, Tomáš (advisor)
The thesis focuses on the development of instruments used for surfaces and nanostructures characterization. Individual techniques of scanning probe microscopy provide different information of the sample surface. The resolution of scanning probe microscopy, providing 3D topography information, reaches subnanometer values or even an atomic level. Therefore, the scanning probe microscopy is one of the most employed method in the field of nanotechnology. The thesis describes the details of development of two scanning probe microscopes intended for measurement under ultra high vacuum conditions. As for the first one, many changes were proposed leading to its better variability, extended functionality and increased user comfort. The second microscope is being design with the aim of its combination with other analytic techniques, especially with scanning electron microscopy. An integral part of scanning probe microscopes is a precise positioning system for navigation of the probe to the selected site. Therefore, the thesis also deals with the development of linear piezoceramic actuators used not only in the ultra high vacuum compatible microscopes but also as a general purpose nanomanipulators.
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Microdefects in Czochralski Silicon
Válek, Lukáš ; Fejfar, Antonín (referee) ; Mikulík, Petr (referee) ; Spousta, Jiří (advisor)
Disertační práce se zabývá studiem defektů v monokrystalech Czochralskiho křemíku legovaných bórem. Práce studuje vznik kruhových obrazců vrstevných chyb pozorovaných na povrchu křemíkových desek po oxidaci. Hlavním cílem práce je objasnit mechanismy vzniku pozorovaného rozložení vrstevných chyb na studovaných deskách a vyvinout metody pro řízení tohoto jevu. Na základě experimentálních analýz a rozborů obecných mechanismů vzniku defektů jsou objasňovány vazby mezi vznikem defektů různého typu. Tyto jsou pak diskutovány v souvislosti s parametry krystalu i procesu jeho růstu. Takto sestavený model je využit pro vývoj procesu růstu krystalů, kterým je potlačen nadměrný vznik defektů ve studovaných deskách. Za účelem studia defektů jsou zaváděny a vyvíjeny nové analytické metody. Disertační práce byla vytvořena za podpory ON Semiconductor Czech Republic, Rožnov pod Radhoštěm.
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