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Substrate-controlled nucleation of the magnetic phase transition in nanostructures
Hajduček, Jan ; Procházka, Pavel (referee) ; Uhlíř, Vojtěch (advisor)
Properties of the phase transition in iron-rhodium (FeRh) from the antiferromagnetic (AF) to ferromagnetic phase (FM) are largely affected by lattice defects in FeRh. Epitaxial layers of FeRh are grown on monocrystalline MgO (001) substrates. Surface atomic terraces of the substrate can induce defects in epitaxial layers and modify electronic and magnetic properties. In this thesis the effect of surface atomic terraces on the width and the hysteresis of the metamagnetic phase transition in FeRh thin layers and nanostructures is studied. The amount and character of defects in FeRh are also affected by mutual orientation of terraces and FeRh nanowires, which changes the number of discrete jumps in FM-AF transition. The nanowires have been fabricated by electron-beam lithography. FM domains in in FeRh have been observed by magnetic force microscopy and electrical transport properties of differently oriented nanowires have been studied by 2-probe measurements. Higher density of surface atomic terraces significantly increases the number of discrete jumps in the FM-AF transition.
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Measurement of graphene transport properties
Nečesal, Daniel ; Procházka, Pavel (referee) ; Kormoš, Lukáš (advisor)
In order to create electronic devices utilizing graphene, it is necessary to manu- facture large sheets of high quality graphene which can be achieved by chemical vapor deposition (CVD). Mobility plays an important role in determining quality of graphene sheet because it is inversely proportional to concentration of defects. In this work, CVD graphene samples were fabricated, and their transport properties were characterized by van der Pauw and Hall bar methods. Graphene was transferred to samples either by using Fe(NO3)3 solution or via electrolytic delamination process. Both methods yiel- ded highly p-doped graphene. The electrolytic delamination transfer process resulted in a higher mobility of the graphene sheet and the Dirac point was observed due to a significant doping decrease.
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Modelling of photonic structures using Finite-difference time-domain method
Procházka, Pavel ; Kalousek, Radek (referee) ; Petráček, Jiří (advisor)
This bachelor thesis is focused on the basic description of the finite-difference time-domain method (FDTD) which serves to the numerical solution of Maxwell's equations. FDTD is very used today because during one calculation it is possible to obtain results in wide frequency spectrum. The thesis contains deduction of \mbox{equations} for description of this method and algorithm of calculation. The main goals of this thesis are the identification of the free Meep software, which is constructed for this calculations, and understanding of its properties. Most of Meep functions are described on three examples in the second part of bachelor thesis.
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Fabrication of Graphene and Study of its Physical Properties
Procházka, Pavel ; Rezek, Bohuslav (referee) ; Kalbáč,, Martin (referee) ; Dub, Petr (advisor)
This doctoral thesis is focused on the preparation of graphene layers by Chemical Vapor Deposition (CVD) and their utilization for fabrication and characterization of field effect transistors. The theoretical part of the thesis deals with different methods of graphene production and measurement of its transport properties. In the first part of the experimental section the growth of polycrystalline graphene and individual graphene crystals with sizes up to 300 m is investigated. Further, graphene layer was also grown on an atomically flat copper foils, which were fabricated in order to achieve the growth of graphene of higher quality. Subsequently, the transport properties of field effect transistors produced from the grown layers were measured. The last two chapters deal with a doping of graphene layer by gallium atoms and X-ray radiation. Whereas the deposition of gallium atoms on the graphene surface causes chemical doping of graphene layer by charge transfer, X-ray irradiation of graphene field effect transistors induces the ionization of positively charged defects in dielectrics, which electrostatically dope a graphene layer.
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Transport properties of single graphene domains
Vysocký, Filip ; Kormoš, Lukáš (referee) ; Procházka, Pavel (advisor)
This bachelor thesis is focused on the preparation of single graphene domains by chemical vapor deposition method, its transfer onto non-conductive substrates and subsequent fabrication of the grapehene field effect transistors. The theoretical part of the tesis deals predominantly with different procedures of graphene production. The practical part of the thesis describes the production of graphene field effect transistors by electron beam lithography and the measurement of their transport properties.
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Marketing in Tourism
Bogner, Josef ; Procházka, Pavel (referee) ; Chalupský, Vladimír (advisor)
This thesis analyzes the micro-region Moravskokrumlovsko in the tourism sector and proposes solutions to increase its tourist attractions. The theoretical part of this thesis is focused on marketing research, tourism marketing and related concepts. The practical part is focused on analysis of attractiveness, analysis of visitors, analysis of marketing mix, analysis of competitors, secondary research focusing on visitors of the micro-region, primary research focusing on promotion of the micro-region, and suggestions for improving the tourist attractions of micro-region.
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Metal-organic interface for effective charge transfer
Mrhačová, Petra ; Průša, Stanislav (referee) ; Procházka, Pavel (advisor)
This bachelor thesis deals with the analysis of benzene-1,3,5-tricarboxylic acid (TMA) molecules on a silver crystal with (111) surface termination. After the deposition of the molecules on the substrate, a fully protonated layer ( phase) is formed. Further substrate annealing induces a deprotonation process, which leads to the formation of another and phases. The different arrangements of the molecules were studied in ultra-high vacuum conditions by low-energy electron microscope (LEEM), scanning tunneling microscope (STM), and by low-energy electron diffraction (LEED). The application potential of these layers is discussed.
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The preparation of Grafen by method CVD
Procházka, Pavel ; Kromka,, Alexander (referee) ; Mach, Jindřich (advisor)
This diploma thesis is mainly focused on the fabrication of graphene layers on the copper foil by the Chemical Vapor Deposition (CVD). For this purpose the high-temperature chamber for the production of the graphene was completed and fully automated. The production of the high area graphene on the copper foil was experimentally achieved. The Raman microscopy and X-ray photoelectron spectroscopy measurements proved that the produced graphene is mostly a monolayer. Graphene layer was transferred on non-conductive substrate.
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