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Preparation and testing of SNOM probes
Bobek, Juraj ; Pavera, Michal (referee) ; Spousta, Jiří (advisor)
The area of research that deals with surface modification and preparation of nanostructures is still very unexplored. And only a little contribution to this field is discussed in this bachelor thesis. Its goal is to manufacture and to test a probe made off hollow optical fibre that is used in Scanning Probe Microscopy. Optical fibre parameters in combination with proper and unique techniques allow the breakthrough off very interesting applications. It's worth mentioning the gas injection in the proximity of the surface of a sample (GIS) and thus its modification by use of electrons (FEBID), ions (FIBID) or laser beams.
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Chemical Machining Technology
Macháček, David ; Kolář, Ladislav (referee) ; Osička, Karel (advisor)
This bachelor thesis describes the most used methods of chemical machining in the industry. There are discussed the basic principles of particular methods, their advantages and disadvantages, as well as their best use in terms of economics. The properties of used chemicals and basic safety in working with them are also mentioned.
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Production and characterization of nanoporous alumina membranes
Šimik, Milan ; Márik, Marian (referee) ; Kynclová, Hana (advisor)
The Bachelor thesis mostly deals with manufacturing of membranes with anodic oxidation of aluminium in different conditions. In theoretical part are studied processes leading to creating of porous alumina and methods of measuring permeability of membranes. Practical part is aimed on manufacturing porous alumina with different conditions, which are afterwards suffused into form and diffuse characterized. Measured parametres are interpreted and compared with each other.
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Low power MEMS heating membrane
Svatoš, Vojtěch ; Pekárek, Jan (referee) ; Hubálek, Jaromír (advisor)
The aim of this thesis is to create the MEMS heating membrane with low power consumption. This work includes the main of design and fabrication processes of these heating elements. It was decided that the final sample will be created as suspended membrane type of the structure. It the end of the thesis there is detailed overview of the whole fabrication processes used for fabrication of final samples and the experiment to prove the resistance due to thermal stress.
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CREATION OF NANOSTRUCTURES ON SURFACES OF SOLID MATTER USING HYBRID METHODS
Rudolfová, Zdena ; Mikulík, Petr (referee) ; Horová, Ivana (referee) ; Kolíbal, Miroslav (advisor)
This thesis deals with the study of GaAs surface properties and with methodology of metal (mainly gold) nanoparticles deposition on GaAs substrate. GaAs has complicated surface oxides structure, which are very reactive when exposed to various chemicals (both acids and alkalines) and therefore they change GaAs surface properties. That is why the study of this properties is crucial for understanding of GaAs surface reactions on metal particles colloidal solution, from which the nanoparticles are deposited on the surface. The possibilites of GaAs surface etching and passivation are discussed. These should lead to surface stability enhancement during colloidal nanoparticles deposition. There was also studied the influence of adhesive polymer monolayer grown on GaAs substrate to the amount of nanoparticles deposited to the surface after substrate immersion into colloidal solution. This thesis concentrates on analyzing of methods, how the gold colloidal nanoparticles can be deposited selectivelly, only to defined areas. The areas were defined using charged particle beam.
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Preparation and characterization of highly hydrophobic coatings on AZ 91 magnesium alloy
Šomanová, Pavlína ; Hasoňová, Michaela (referee) ; Doskočil, Leoš (advisor)
Magnesium and its alloys have many interesting properties and thanks to them it can be used in many applications (transport industry, medicine etc.). Disadvantage of these materials is their high corrosion rate. For this reason, there is an effort to achieve high corrosion resistance through different modifications of magnesium and its alloys. In recent years the superhydrophobization of the surface seem to be an attractive solution for this question. This type surface modification minimalize contact between the surface and water. In this diploma thesis the superhydrophobic surface was created on the magnesium alloy AZ91. The first step included pretreatment of AZ91 surface by etching in solution of SnCl2 or ZnCl2. Next step was superhydrophobization in the ethanolic solution of stearic acid. The surface morphology and elemental analysis of the superhydrophobic coating were explored by use of scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS). The adhesion properties of the coating on the AZ91 were analysed by means of scratching test. Contact and sliding angles were measured for superhydrophobic coatings. Electrochemical characterization of the coatings was determined using potentiodynamic polarization (PD) and electrochemical impedance spectroscopy (EIS). Finally, the analysis of composition and the functional groups was made using Fourier-transform infrared spectroscopy (FTIR) and the phase composition analysis was performed using X-ray diffraction (XRD). The results show that the coatings prepared by etching did not lead to good corrosion properties, even though the value of contact angle was about 150 °. The reduction of corrosion resistance could be caused by not obtaining required surface morphology or insufficient binding of stearic acid in the form of stearate to the sample surface.
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GaN deposition on a tungsten substrate
Pikna, Štěpán ; Piastek, Jakub (referee) ; Čalkovský, Vojtěch (advisor)
This bachelor thesis is focused on deposition of GaN nanocrystals on the etched tungsten tips. Motivation was to prepare these GaN structures on the Schottky cathode made by company ThermoFisher Scientific and measure its field emission. In the theoretical part of the thesis GaN and tungsten field emission properties are introduced. The experimental part begins with tungsten tip etching optimalization, where the right values for best tips are temperature 20 °C, depth of the tip 2,5 mm and solution NaOH used. Further the gallium structures were prepared on these tips using molecular beam epitaxy (MBE). The right temperature to prepare GaN nanocrystals was determined as 200 °C. The deposition of gallium was set to 2 hours and following nitridation was 3 hours. Finally, the field emission from GaN prepared on copper foil with graphene was measured and compared with other experiments.
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Local electrical conductivity measurements in AFM tapping mode
Dao, Radek ; Konečný, Martin (referee) ; Pavera, Michal (advisor)
This bachelor thesis is concerned about the development of a probe for local electrical conductivity measurements in tapping mode Atomic Force Microscopy. The teoretical part gives a short overview of Scanning Probe Microscopy techniques, with the focus being on Conductivity Atomic Force Microscopy. Furthermore, the measuring regime in which the probe operates is described here, as well as the basic component of the probe, the quartz tuning fork. The experimental part follows the iterative development process, and contains a chapter dedicated to making of very sharp tips. The final chapters describe the preparation of test samples, which were used to prove the functionality of the probe and the measurement of local electrical conductivity itself.
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Fabrication of micro- and nanostructures by different etching methods
Těšík, Jan ; Urbánek, Michal (referee) ; Šamořil, Tomáš (advisor)
The selective etching is currently very widely used method for the preparation of micro- and nanostructures. This thesis deals with the principles of the etching methods, their applications and also the possibilities of dry and wet etching at the Institute of Physical Engineering. The experimental part is devoted to the preparation of the etching masks to ensure etching selectivity and to the preparation of pre-defined micro- and nanostructures. Important parameters were determined from the results, e.g. Si etch rate, selectivity of the masks etc. Further, the suitability of the used methods and etching masks were compared.
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