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Applications of metallic probe for the control of optical processes and near-field imaging
Gallina, Pavel ; Klapetek, Petr (referee) ; Křápek, Vlastimil (advisor)
Hlavním předmětem této diplomové práce jsou elektromagnetické simulace pomocí metody konečných prvků (FEM) k vyšetření vlivu grafenu na hrotem zesílenou Ramanovu spektroskopii (TERS) a povrchem zesílenou infračervenou absorpční spektroskopii (SEIRA) a k prozkoumání citlivosti sondy skenovacího optického mikroskopu blízkého pole (SNOM) ke složkám elektromagnetického pole v závislosti na parametrech sondy (průměru apertury v pokovení). Nejprve je proveden výpočet TERS systému složeného ze stříbrného hrotu nacházejícího se nad zlatým substrátem s tenkou vrstvou molekul, jehož účelem je porozumění principů TERS. Poté je na molekuly přidána grafenová vrstva, aby se prozkoumal její vliv ve viditelné (TERS) a infračervené (SEIRA) oblasti spektra. Druhá část práce se zabývá výpočty energiového toku SNOM hrotem složeným z pokoveného skleněného vlákna interagujícím s blízkým polem povrchových plasmonových polaritonů. Zde uvažujeme zlatou vrstvu se čtyřmi štěrbinami uspořádanými do čtverce na skleněném substrátu sloužícími jako zdroj stojatého vlnění povrchových plasmonů s prostorově oddělenými maximy složek elektrického pole orientovanými rovnoběžně či kolmo na vzorek. Ve výpočtech hrotem zesílené spektroskopie zjišťujeme, že grafen přispívá pouze malým dílem k zesílení pole ve viditelné oblasti spektra, ovšem v infračervené oblasti má grafen vliv pro záření s energií menší než dvojnásobek Fermiho energie grafenu, pro kterou je hodnota zesílení pole větší než v případě výpočtu bez grafenu. Avšak pro velmi vysoké vlnové délky zesílení pole v přítomnosti grafenu klesá pod (konstantní) hodnotu pro případ bez grafenu. Při studiu citlivosti SNOM hrotu k jednotlivým složkám pole shledáváme, že pro hrot se zlatým pokovením je energiový tok skleněným jádrem hrotu kombinací příspěvků energie prošlé aperturou a periodické výměny energie mezi povrchovým plasmonem šířícím se po vnějším okraji pokovení a mody propagujícími se v jádře. Dále zjišťujeme, že hroty s malou aperturou (či bez apertury) jsou více citlivé na složku elektrického pole orientovanou kolmo ke vzorku (rovnoběžně s osou hrotu), zatímco hroty s velkou aperturou sbírají spíše signál ze složky rovnoběžné s povrchem vzorku. V případě hrotu s hliníkovým pokovením jsou hroty citlivější ke složce pole rovnoběžné s povrchem, což je způsobeno slabším průnikem pole skrze pokovení.
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Numerical simulation of the laser light scattering from rough surfaces
Šulc, Václav ; Klapetek, Petr (referee) ; Ohlídal, Miloslav (advisor)
A Matlab numerical model for scattering simulation was proposed based on the solution derived from the Beckmann-Kirchhoff scalar theory of scattering of electromagnetic waves from rough surfaces. A series of various synthetic surface samples were obtained using the open source software Gwyddion on which numerical simulations of scattering were carried out. The validity of this numerical model was tested and compared with experimental results.
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Manufacturing, use and properties of duplex austenitic-ferritic steels
Klapetek, Václav ; Blažík, Petr (referee) ; Myška, Martin (advisor)
This bachelor thesis focuses on stainless duplex austenitic-feritic steels. The first chapter is focused on mechanical and technological properties, microstructure and chemical proposition with its impact on corrosion resistance, following the introduction to the issue. Intermetallic phases and their effect on properties are also described. Second chapter deals with their usage in several industry spheres, such as petrochemical industry, paper-producing, transport and storage of chemicals etc.
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Advanced Interferometric Methods of Coordinates Measurement
Holá, Miroslava ; Klapetek,, Petr (referee) ; Mrňa, Libor (referee) ; Lazar, Josef (advisor)
This thesis addresses particular topics in the field of the length metrology for nanometrology. Nanometrology deals with dimensional measurements of micro- and nanostructures with a high spatial resolution. It typically combines a microscope imaging with a precise coordinate measurement, usually capable of nanometre resolution using the state-of-art laser interferometry techniques. The development in this field is driven, among others, by emerging advanced nanotechnologies that demand to push further the capabilities and limits of the interferometric techniques to make the nanometre-level dimensional measurement of nanostructures possible. The principal limitations of current systems are the environmental conditions and especially the fluctuations in the refractive index of air. The theoretical part of this thesis aim at analysis of individual parts of laser interferometer. I oriented myself on the study of their advantages/disadvantages and further also the possibilities of their industrial applications. The second part of the thesis presents my work that focused on the influence of the refractive index of air (RIA) on the measurement uncertainty. I experimentally demonstrated an interferometric system with a self-cancellation RIA fluctuations: a transparent photodetector is used for the measurement of the standing wave along the axis of a passive resonator, where the resonator also serves as a reference for the laser wavelength stabilisation. Another optical arrangement, based on a setup of several Michelson interferometers, represents a combination of an interferometer and a refractometer into a single system. This setup was used to study the behaviour of the ambient airflow with respect to the optical path difference and physical separation of the interferometer’s and refractometer’s path. Based on the experimental results I proposed new arrangements for shape measuring interferometers, which combine length interferometry and a tracking refractometer for the direct compensation of RIA fluctuations with geometrically adjacent optical beams. The results indicate an improvement in RIA fluctuation induced uncertainty by a factor of 100. Third part describes the design and implementation of interferometric systems for specific applications. For the industrial environment I developed a compact interferometric displacement gauge which is designed to allow nanometre level measurement using a simplified interferometer construction. For coordinate measurement of the position of the sample up to six degrees of freedom, I realised a compact modular interferometric system, which represents a unique setup together with a stabilised laser source. To measure the position of the sample in an electron beam writer chamber, I designed and implemented a differential interferometer that works in the near infrared domain and uses a new detection method developed for this system. In the fourth part I describe the realisation of a high-speed interferometer with a differential arrangement, which allows evaluation of high-cycle fatigue in material engineering. This method of studying high-cycle fatigue should be beneficial for both the basic research and the engineering practice.
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Investigating model CeO2 and TiO2 systems by means of Scanning Tunneling Microscopy and Atomic Force Microscopy
Stetsovych, Oleksandr ; Mysliveček, Josef (advisor) ; Jelínek, Pavel (referee) ; Klapetek, Petr (referee)
Atomic scale characterization of materials is important for the fundamental understanding of their properties. Here, model systems of industrially relevant cerium and titanium oxides are characterized with the combination of the Scanning Tunneling Microscopy (STM) and Non Contact Atomic Force Microscopy (NC AFM). Cerium oxide model systems are represented by fully oxidized and partially reduced ultra-thin ceria films supported on copper single crystal. Interaction of the model ceria systems with catalytically important adsorbates (water, methanol) is studied on atomic scale. Titanium oxide model systems are represented by pentacene and C60 molecules adsorbed on the surface of bulk titania in anatase polymorph. Organic layers on titania are studied with intramolecular resolution with the help of the newly developed Double pass scanning mode of NC AFM. The atomic contrast formation mechanisms in STM and NC AFM on ceria and anatase surface are presented. Powered by TCPDF (www.tcpdf.org)
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Structuring and study of electronic and chemical properties of semiconductor surfaces
Verveniotis, Elisseos ; Rezek, Bohuslav (advisor) ; Bartošík, Miroslav (referee) ; Klapetek, Petr (referee)
of thesis Semiconductor materials play a crucial role in modern society as they have become integral parts of our daily life through personal computers, mobile phones, medical implants, solar panels and a plethora of other commercially available electronic devices. The semiconductor industry has been relying predominantly on silicon so far and will continue to do so for a few more years, until the material limits for miniaturization and device engineering are reached. Fortunately, worldwide research has already demonstrated that there are materials exhibiting superior mechanical, electronic, and optical properties and which can thus replace or at least complement silicon. This represents a very important step towards satisfying the ever rising global demand for smaller, faster, energy-efficient and cheaper electronic devices. To that end, nowadays research is focused on fabrication and characterization of diverse materials and nanostructures which are aimed to be integral in electronic devices. Due to the miniaturization, it is essential that the electronic, structural and chemical characterization and modification of those novel materials and structures is performed on the microscopic scale. The relatively young but nevertheless rapidly expanding and exciting field of nanoscience and...
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Luminescence of semiconductors studied by scanning near-field optical microscopy
Těšík, Jan ; Klapetek, Petr (referee) ; Křápek, Vlastimil (advisor)
This work is focused on the study of luminescence of atomic thin layers of transition metal chalkogenides (eg. MoS2). In the experimental part, the work deals with the preparation of atomic thin layers of semiconducting chalcogenides and the subsequent manufacturing of plasmonic interference structures around these layers. The illumination of the interference structure will create a standing plasmonic wave that will excite the photoluminescence of the semiconductor. Photoluminescence was studied both by far-field spectroscopy and near-field optical microscopy.
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Interaction of group III and IV metals with Si(100) surface in temperature range from 20 to 800K
Setvín, Martin ; Ošťádal, Ivan (advisor) ; Janda, Pavel (referee) ; Klapetek, Petr (referee)
1 Title: Interaction of group III and IV metals with Si(100) surface in temperature range from 20 to 800 K Author: Martin Setvín Department: Departement of Surface and Plasma Science Supervisor of the doctoral thesis: Doc. RNDr. Ivan Ošt'ádal CSc. Abstract: Interaction of group III and IV metals with Si(100) surface was studied by STM (Scanning Tunneling Microscopy) and AFM (Atomic Force Microscopy) in temperature range from 20 to 800 K. Adsorption and hopping of single metal adatoms on Si(100)-c(4×2) reconstruction can be observed by STM at low temperatures. Activation energies and frequency prefactors for hopping of single indium atoms were measured by two meth- ods - direct STM measurement at low temperature and Kinetic Monte Carlo simulations of layer growth at room temperature. Group III and IV atoms self-assemble into single atom wide chains on Si(100) surface at about room temperature. Atomic and electronic structure of the chains was investi- gated by means of STM and dynamic non-contact AFM. Keywords: Si(100), STM, AFM, adsorption, diffusion
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The neuropsychological developmental screening NES - a pilot study of its applicability in the Czech context
Klapetek, Anna ; Kulišťák, Petr (referee) ; Šturma, Jaroslav (advisor)
The neuropsychological developmental screening NES was created for German pediatric practice and allows to quickly assess the developmental state of children between 2 and 24 months of age. At 2-4 and 5-7 months, the test assesses regulation of posture and movement, fine motor control, visual perception and cognitive skills, at 9-12 months visual perception tasks are replaced by exploration behavior tasks, while at 16-19 and 22-24 months posture and movement regulation, visuomotor skills, receptive and expressive language, and cognitive skills are evaluated. The aim of this thesis was to introduce the screening and test its applicability in the context of Czech Republic. The theoretical part summarizes current knowledge on child development in the first two years, specifies the term developmental delay and discusses methodological problems associated with developmental diagnostics. Lastly, the theoretical grounding of the NES is described. In the empirical part, a Czech language version of the NES was created and subsequently administered to 50 Czech children. Despite the overall positive experience with the NES, weak points were identified in the original test instructions, which were modified in the Czech manual. The quantitative results allowed the identification of critical test items. Moreover,...
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Design and Realization of the Second Generation Imaging Reflectometer and its Application in Optical Analysis of Thin Films
Vodák, Jiří ; Držík,, Milan (referee) ; Klapetek, Petr (referee) ; Ohlídal, Miloslav (advisor)
The work deals with a technique of imaging spectroscopic reflectometry developed at The Institute of Physical Engineering, Brno University of Technology. The technique is well suited for characterization of samples non–uniform along their surfaces. The technique is primarily used for optical characterization of thin films. First part of the work is focused on basic physical principles of the technique and on ways in which measurement data are obtained. It contains a basic description of evaluating methods and a basic concept of an imaging spectroscopic reflectometer with a description of main parts of such a device. The main part of the work is focused on a description of two devices which were built at The Institute of Physical Engineering together with a description of some of upgrades which were implemented to these devices during their development. A description of measurements done with the two devices is also included. Last part of the work is then focused on further development of the technique. Intention of possible evolution of the technique to imaging spectroscopic ellipsometry is proposed.
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