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Preparation of InAs nanowires by MBE
Stanislav, Silvestr ; Maniš, Jaroslav (referee) ; Musálek, Tomáš (advisor)
The bachelor’s thesis deals with growth of InAs nanowires grown on silicon substrate by molecular beam epitaxy. The emphasis is mainly layed on fabrication of nanowires grown via Vapour-Liquid-Solid mechanism using gold catalytic nanoparticles. There is a brief description of two most common mechanisms of nanowire growth in the first part of the thesis. The text also discusses crystal structure of InAs and doping options of InAs nanowires. The experimental part is aimed at deposition and the impact of different growth conditions on both growth mechanism and nanowire morphology.
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Growth of highly doped ZnO nanowires
Andrýsek, Michal ; Macák, Jan (referee) ; Kolíbal, Miroslav (advisor)
This diploma thesis is about ZnO nanowires growth, their doping and analysis. High temperature and pressure oxidation of brass foil and deposition from effusion cell in oxidative atmosphere utilized for nanowires growth. The growth is affected by different temperature and pressure. It has been shown that under certain experimental conditions nanowires can be prepared by the former method. However, the growth was hindered when effusion cell was used.
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Nanostructures and Nanosensors
Křečková, Jitka ; Haupt, Jaromír (referee) ; Ellederová, Eva (advisor)
Cílem této bakalářské práce je představit využití nanotechnologie ve snímacích zařízeních, poskytnout základní informace o nanotechnologii, včetně popisu a klasifikace nanostruktur, a zdůraznit možnost vylepšení výkonu senzoru prostřednictvím nanotechnologie. Tato práce se také zabývá využitím nanodrátu jako součástí senzoru s konfigurací unipolárního tranzistoru. Kvantové tečky a jejich využití v optické detekci jsou také zahrnuty v této práci. Výhody i současná omezení nanosenzorů jsou shrnuty v závěru práce.
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Transport properties of one dimensional magnetic nanostructures
Holobrádek, Jakub ; Liška, Jiří (referee) ; Vaňatka, Marek (advisor)
Magnetic nanowires have been recently under the scope for their specic properties and applications in microelectronics and sensors. This work deals with measurement of transport properties of nanowires in magnetic field. Nanowires prepared in the range of the thesis were grown by the physical vapor deposition method in colaboration with the University of Technology Sydney. The main task of the thesis was to develop a process of contacting single nanowires by electron beam lithography and measuring them using anisotropic magnetoresistance in angle dependent magnetic field. Characterization techniques such as transmission electron microscopy, energy-dispersive X-ray spectroscopy and magnetic force microscopy were used to provide further analysis.
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Preparation of contacts to one-dimensional nanostructures
Citterberg, Daniel ; Procházka, Pavel (referee) ; Kolíbal, Miroslav (advisor)
This bachelor thesis deals with methodology of contacting one-dimensional nanostructures. Theoretical part of the thesis defines the concept of one-dimensional nanostructures, then it deals with the potential of their usage, especially in field effect transistors. This part also deals with the possibility of measuring the electrical properties of one-dimensional nanostructures and the possibility of fabricating contacts with sufficiently small sizes using litographic approach. Experimental part gives a brief overview of the tasks that need to be done during the contact fabrication. Subsequently, the individual steps are described in more detail and, finally, initial results of electrical characterization are shown.
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Growth of ZnO nanowires
Mikula, Martin ; Voborný, Stanislav (referee) ; Kolíbal, Miroslav (advisor)
In this thesis the most important properties of nanowires are briefly characterized and possible methods of their synthesis are described. Special attention is paid to zinc oxide nanostructures as well as VLS mechanism, which is crucial for explanation of nanowire growth. Furthermore, deposition chamber for growth of ZnO nanowires has been assembled and effusion cell for zinc has been tested. Testing of the cell revealed one major drawback of its design, which prevents its use for zinc deposition. Therefore, no growth of ZnO nanowires has been carried out and before it can be accomplished, the effusion cell has to be modified.
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Analysis of one-dimensional structures using Kelvin Probe Force Microscopy
Kovařík, Martin ; Bartošík, Miroslav (referee) ; Kolíbal, Miroslav (advisor)
This bachelor's thesis deals with the use of Kelvin probe force microscopy (KPFM) for analysis of 1D nanostructures, namely germanium nanowires and tungsten disulfide (WS2) nanotubes. First part of this thesis is dedicated to the possibility of gold nanoparticles detection on germanium nanowires and also to the analysis of relevance of the KPFM method to measurements performed at various humidity. Second part deals with the measurement of surface potential changes on WS2 nanotubes induced by interaction with light. We have concluded, that relative surface potential changes can be measured at various humidity. This conclusion is also applied to study the interaction of WS2 nanotubes with monochromatic light. The experiment has revealed, that when exposed to light with defined wavelength, nanotubes coated with gold nanoparticles show opposite surface-potential changes as compared to pristine nanotubes, which indicates different physical processes under way.
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Oxidation barriers prepared by electrochemical procedures
Šťastná, Eva ; Pouchlý, Václav (referee) ; Jan, Vít (advisor)
A process with aim to prepare an oxidically and thermal resistant layer was performed on the samples from clear aluminium (99,99+ %, VÚK čisté kovy, s. r. o.) and on the samples from clear titanium (99,95 % Goodfellow) with a layer from sputtered aluminium (99,99 %, VÚK čisté kovy, s. r. o.), An oxidic layer was prepared on the samples by anodization in the oxalic acid. The layer had fine, hexagonally organized pores with the diameter of 30 nm. During the following processing was the structure prepared for the electrochemical deposition of copper to the pores. The aim of the electrodeposition was preparation of copper nanowires deposited into the pores of the oxidic layer. The process was performed in the solution of copper sulfate and sulfuric acid in water. The controlling parameter of the deposition was voltage which had a very asymmetric period. The period had to be optimized for a successful preparation of the wires. The result of the whole process was structure with oxidic matrix whose most of the pores were filled with copper.
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Investigation of nanomaterials for their nuclear power and research utilization
Jelínek, Martin ; ČEZ,, Jiří Skalička, (referee) ; Katovský, Karel (advisor)
This bachelor thesis provides a comprehensive overview of the properties of various nanomaterials and summarizes the latest findings and knowledge of advanced applications in all sectors of nuclear power engineering from construction materials through nuclear fuel, fuel cladding, neutron moderator and coolant to the advanced methods for detection of ionizing radiation ad its direct utilization for electricity production. A significant space is devoted to the applications in safety systems of nuclear power plants. The experimental part of the thesis deals with the possibility of using carbon nanofibers as an additive to the coolant in VVER reactor type in order to improve the thermal properties of the coolant. So far a very little examined issues of neutron balance changes due to interaction with nanoparticles was experimentally verified on the paraffin wax mixture of two different concentrations. The comparison with the reference sample of pure paraffin was also made.
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