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Deposition of Molecular Magnets on „2D“ Materials
Vavrečková, Šárka ; Musálek, Tomáš (referee) ; Hrubý, Jakub (advisor)
This thesis deals with deposition of single-molecule magnets on 2D materials and studies their behavior on surfaces. Theoretical part contains information about properties of single-molecule magnets, deposition methods and also information about chosen 2D materials – graphene and molybdenum disulfide. Further, the physical principles of the selected characterization methods (atomic force microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and electron paramagnetic resonance) are described. In the experimental part graphene and molybdenum disulfide were exfoliated. Afterwards, depositions of single-molecule magnets from solution and by thermal sublimation were made. After that, samples were analyzed using the mentioned methods and results were discussed.
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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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Optical characterization of InAs nanowires
Hošková, Michaela ; Ligmajer, Filip (referee) ; Musálek, Tomáš (advisor)
This bachelor thesis deals with the fabrication and optical characterization of InAs nanowires. Physical vapor deposition is used for the fabrication of nanowires via method selective epitaxy in the MBE chamber. The growth conditions for the formation of nanowires are optimized and their dimensions are characterized by a scanning electron microscope. Confocal spectroscopy and electron energy loss spectroscopy are employed for measurement of the optical response and the influence of the geometry of individual nanowires is studied. The motivation is the development of a new optical method that monitors nanowires directly during growth in the MBE apparatus.
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Preparation of low-dimensional inorganic perovskites
Nedvěd, Matěj ; Dvořák, Petr (referee) ; Musálek, Tomáš (advisor)
This bachelor thesis deals with the perovskite CsPbBr3. The thesis presents properties and different ways of preparing nanostructures of this inorganic perovskite. The emphasis is placed on physical vapor deposition using effusion cells. The experiments carried out to prepare nanocrystals and nanowires and the subsequent analysis of their morphology, composition and optical properties are described. The effect of the electron beam and long-term exposure to air on the optical properties is studied. Also, the concept of an experiment that should result in the replacement of lead in the perovskite structure by tin is presented.
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Semiconductor nanowire growth utilizing alloyed catalyst
Musálek, Tomáš ; Rezek, Bohuslav (referee) ; Kolíbal, Miroslav (advisor)
This master's thesis deals with growth of germanium nanowires using different catalyst particles. The emphasis is mainly layed on fabrication of specific alloyed catalyst consisting of (AgGa). In the first part of the thesis are mentioned two most common concepts of nanowire growth and the importance of phase diagrams for their interpretation. Method for production of alloyed catalyst is demonstrated and experiments focused on the growth of germanium nanowires using this catalyst were performed. Moreover, method for modification of germanium surface via anisotropic etching is demonstrated as well. Such etched structures are suitable for nanowire growth with the help of different kinds of catalyst particles or for the growth of nanowires made of various materials.
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Fabrication and structuring of a thin vanadium dioxide layer for nanophotonics
Spousta, Jiří ; Musálek, Tomáš (referee) ; Rovenská, Katarína (advisor)
Vanadium dioxide is becoming frequently used in tunable metasurfaces, mainly due to its easily achievable insulator to metal phase-transition, occuring at around 67°C. This thesis deals with the optimization of thin VO2 layer fabrication process and specifically with e-beam evaporation and ion beam-assisted sputtering. The phase change of VO2 layers was optically characterized -- mostly, we measured the thermally-dependent transmissivity of our layers. In ion beam-assisted sputtering, we implemented a new process for yielding thin VO2 layers which uses in situ annealing during the deposition. Layers fabricated with this newly implemented process demonstrate a clear phase transition typical for VO2.
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Optical characterization of InAs nanowires
Hošková, Michaela ; Ligmajer, Filip (referee) ; Musálek, Tomáš (advisor)
This bachelor thesis deals with the fabrication and optical characterization of InAs nanowires. Physical vapor deposition is used for the fabrication of nanowires via method selective epitaxy in the MBE chamber. The growth conditions for the formation of nanowires are optimized and their dimensions are characterized by a scanning electron microscope. Confocal spectroscopy and electron energy loss spectroscopy are employed for measurement of the optical response and the influence of the geometry of individual nanowires is studied. The motivation is the development of a new optical method that monitors nanowires directly during growth in the MBE apparatus.
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Fabrication and structuring of a thin vanadium dioxide layer for nanophotonics
Spousta, Jiří ; Musálek, Tomáš (referee) ; Rovenská, Katarína (advisor)
Vanadium dioxide is becoming frequently used in tunable metasurfaces, mainly due to its easily achievable insulator to metal phase-transition, occuring at around 67°C. This thesis deals with the optimization of thin VO2 layer fabrication process and specifically with e-beam evaporation and ion beam-assisted sputtering. The phase change of VO2 layers was optically characterized -- mostly, we measured the thermally-dependent transmissivity of our layers. In ion beam-assisted sputtering, we implemented a new process for yielding thin VO2 layers which uses in situ annealing during the deposition. Layers fabricated with this newly implemented process demonstrate a clear phase transition typical for VO2.
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Preparation of low-dimensional inorganic perovskites
Nedvěd, Matěj ; Dvořák, Petr (referee) ; Musálek, Tomáš (advisor)
This bachelor thesis deals with the perovskite CsPbBr3. The thesis presents properties and different ways of preparing nanostructures of this inorganic perovskite. The emphasis is placed on physical vapor deposition using effusion cells. The experiments carried out to prepare nanocrystals and nanowires and the subsequent analysis of their morphology, composition and optical properties are described. The effect of the electron beam and long-term exposure to air on the optical properties is studied. Also, the concept of an experiment that should result in the replacement of lead in the perovskite structure by tin is presented.
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