Tato diplomová práce se zabývá dotováním grafenu nízkoenergiovými elektrony. Na křemíkový substrát pokrytý vrstvou SiO2 jsou pomocí litograficky vyrobené masky nadeponované kovové kontakty z titanu a zlata. Grafen vyrobený pomocí metody depozice z plynné fáze je přenesen na substrát a slouží jako vodivé spojení kovových elektrod, které vytvářejí kolektor a emitor. Na křemík je ze spodu přivedeno napětí, které tak vytváří spodní hradlo. Takto vytvořený grafenový tranzistor je ozařován nízkoenergiovými elektrony, které mění dotování grafenu. Z polohy maxima v závislosti odporu grafenu na hradlovém napětí lze vyčíst typ dotování. Toto maximum udává napětí, při kterém Fermiho meze grafenu prochází Diracovým bodem v pásové struktuře grafenu. Velikost hradlového napětí, primární energie elektronového svazku a proud svazku jsou tři parametry, které mají velký vliv na změny dotování. Při ozařování transistoru dochází ke změně typu dotování právě tehdy, když odpor grafenu v závislosti na hradlovém napětí dosáhne maxima. Vývoj této změny je zkoumán pro různé energie a proudy primárního svazku v závislosti na hradlovém napětí i v čase. Typ dotování je také prozkoumán při zastavení ozařování v různých fázích smyčky hradlového napětí. Dopování grafenu nízkoenergiovými elektrony je popsáno v teoretickém modelu.

This master thesis is focused on characterization of electrical transport properties of one-dimensional nanostructures. First section of this work deals with theoretical description of the experimental approaches to realization of such measurements. This section involves also a detail discussion of preparation of contacts using e-beam lithography. Next, theoretical description of characterization of nanostructures using photoluminescence measurements is given. Second section describes practical application of the aforementioned electrical transport measurements. Presented results include transport and photoluminescence measurements of WS2 nanotubes, InAs and WO2.72 nanowires. The last section of this thesis deals with nanowire quantum well heterostructures. The section provides both a deeper theoretical view of the problem and results of the photoluminescence measurements are shown.

Capillary stamping is a versatile patterning platform to create micron/sub-micron features on surfaces. When used in combination with mesoporous silica stamps, dot arrays with length scale characteristics matching those of various biomolecular organizations on living cells can be printed. Therefore, different types of ink with functional molecules were printed onto a glass surface and assessed toward their capability to enable an analysis of cellular interactions. Among the evaluated patterned surfaces were dot arrays generated with heterocyclic silanes, which react in a ring-opening reaction upon contact with hydroxyl-terminated surfaces and allow post-modifications of the stamped dot array. Similarly, functionalized proteins were stamped from an aqueous solution, analyzed in regards to specific geometric descriptors and overall contrast between dot and background. After the establishment of a robust patterning system, the stamped substrates were used to spatially manipulate protein-protein interactions in live cells. With the introduction of optogenetics, namely the photoactivatable iLID-system into HeLa cells, protein recruitment from the cytosol to the membrane-bound domains upon irradiation with light was investigated. The technique was also utilized to explore the determinants of Wnt signalosome formation. Wnt co-receptor Lrp6 expressed at the surface of living cells was successfully assembled into nanodot arrays. Strikingly, the co-receptor Fzd8 and the cytosolic scaffold proteins Axin1 and Disheveled2 were spontaneously recruited into the nanodot array to form spatially defined signalosomes in the absence of ligand pointing toward Liquid-Liquid Phase Separation driven signalosome assembly. Immunofluorescence staining confirmed ligand-independent Wnt/β-catenin signaling activated the nanodot arrays.

In this thesis, the local field enhancement from multiple plasmonic structures were studied in different experiments. A new approach was applied to enhance the emission from upconverting nanoparticles to harvest energy from photons below the bandgap. A novel nanofabrication method was introduced to make double nanoholes for use in optical trapping, which was implemented to observe the nonlinear response from 2D materials and the enhanced emission from upconverting single nanoparticles. This method makes a large amount of apertures and is inexpensive. Selective plasmon-enhanced emission from erbium-doped nanoparticles using gold nanorods was demonstrated. Upconversion nanoparticles were excited with a dual-wavelength source of 1520~nm and 1210~nm simultaneously. The power dependence of the observed upconversion emission confirmed the contribution of both excitation bands in the upconversion process. Gold nanorods with resonances at 980~nm and 808~nm were implemented to selectively enhance the upconversion emission in order to harvest light with Si and GaAs solar cells, respectively. I also used colloidal lithography to fabricate double nanoholes which were plasmonic structures used for protein and nanoparticle trapping. This bottom-up technique enabled the fabrication of a large number of structures at low cost. Plasma etching of polystyrene nanoparticles using this technique tuned the cusp separation of double nanoholes down to 10~nm. The smaller cups separation enables to have more confined field in the gap which can be used in plasmonic sensing and plasmon enhanced upconversion processes. This technique can be used to fabricate plasmonic structures for nanoparticle trapping, spectroscopy, and sensing. In the next project, hexagonal boron nitride nanoflakes were trapped in a double nanohole fabricated with the colloidal lithography method. A second harmonic signal was detected at 486.5~nm where the particle was trapped and pumped with an ultra-low power laser at 973~nm. The power dependence measurements supported the second order process for second harmonic generation. Finite-difference time-domain (FDTD) simulations showed a 500-fold field intensity enhancement at the fundamental wavelength and a 450-fold enhancement in the Purcell factor at the second harmonic generation wavelength. This scheme is promising for ultra-fast imaging nonlinear optics technologies. In the last project, colloidal lithography double nanoholes were used to trap upconverting nanocrystals. Colloidal lithography double nanoholes with 32~nm cusp separation achieved 50 times larger emission compared to rectangular apertures. FDTD simulations showed the largest field enhancement in the aperture with the largest upconversion enhancement. 1550~nm emission from the trapped nanoparticle can be used as single-photon source. / Graduate

The aim of this work is fabrication of nanostructures and measurement of their electrotransport properties. There are two different methods used for fabrication - electron beam lithography with sputtering of thin films and focused ion beam with deposition from gas phase. I-V characteristic was measured for characterisation of as prepared nanostructures - wires. Material of wires prepared by using of electron beam lithography was permalloy - an alloy of iron and nickel. Second types of wires prepared by using of chemical vapor deposition induced by focused ion beam was platinum based.

The diploma thesis deals with the switching of spin vortices in magnetic nanodisks. First, the basic concepts of (micro)magnetism are defined and existing theoretical and experimental achievements in the field of switching of the two basic characteristics (chirality and polarity) of magnetic vortex are summarized. Then the principle of dynamic switching of magnetic vortex chirality using in-plane magnetic field pulse with a well defined amplitude and duration is presented. There is no need to use a certain shape of nanodisks or asymmetry in magnetic field distribution. Nanostructures were prepared by the multi-step electron beam lithography and ion beam sputtering. Individual steps of sample preparation and optimization for the magnetization dynamics measurements are described. Finally, the experimental measurements of the dynamic switching of chirality on prepared samples obtained by transmission x-ray microscopy at the synchrotron Advanced Light Source at Berkeley, USA are presented and discussed.

This diploma thesis deals with study of resonance modes of plasmonic structures. First part provides an overview of theoretical models, which explain the resonanace modes in plasmonic structures. Next part describes technology of electron beam lithography. First section of experimental part deas with technological processes leading to an improvement of resulting structures made by electron beam lithography that is followed by lift-off process. Last part focuses on a study of reflectance spactra of plasmonic antenas and the identification of resonance modes.

This thesis describes several techniques for the optimization of the manufacturing of relief diffractive structures used as optical elements by Electron beam lithograph BS600 in the Electron beam laboratory of the Institute of Scientific Instruments of the Academy of Sciences of the Czech Republic. The Electron beam lithograph BS600 was originally developed and constructed in the Institute of Scientific Instruments of the Academy of Sciences of the Czech Republic for Tesla in 1983, but is still developing, which was published. The Electron been lithograph BS600 is specific in these days because of its accelerating potential and is unique in the world because of the possibility to shape the beam. The optimization of manufacturing of relief diffractive structures, used as optical elements, was mostly reached by analysis, bringing optimal solution for the required effect. Moreover, an algorithm was developed for driving the electron beam position, shape, size and the time of each elementary exposition. The analysis showed that is convenient to use mathematical description of separate lines of diffractive structures. A separate subject was carried out for the calibration of the exposition field of the Electron beam lithograph BS600.

The diploma thesis deals with cellular membrane model preparation on microfluidic devices. It summarizes means of microfluidic device fabrication, phospholipid bilayer formation mechanisms, optimization techniques and characterization methods of those systems. It focuses on free-standing planar lipid bilayers which are easily accessible by a number of different characterization methods and at the same time exhibit good stability and variability. The aim of this work is to design and prepare a microfluidic chip on which a planar lipid bilayer can be prepared. It therefore presents microfluidic device prepared by soft lithography of PDMS adapted for model membrane formation by self-assembly of phospholipids at the interface of aqueous and organic phases created by the architecture of the microfluidic device. Formation of the model membrane was visualized by optical microscopy and fluorescence-lifetime imaging microscopy.

The investigation of the physical properties of deoxyribonucleic acid under confinement is an essential step for the all-embracing understanding of the replication and transcription in living cells as well as for the development of the biomimetic nanotechnology. The following report addresses the measure-ment and interpretation of the intramolecular diffusion along stretched λ-DNA-molecules. This work comprises the fabrication of submicroscopic channels via softlithography, the integration of the chan-nels in an experimental setup with a fluorescence microscope and a source-measurement unit, and the experiments with the DNA-stretching in electrical field. The important results are the development of a measuring assembly with stable, softlithographic structures in Ormostamp, the direct imaging and measurement of the intermolecular diffusion along stretched DNA-molecules in channels with cross sections down to 100 x 300 nm2, and the qualitative and quantitative analysis on the basis of models of polymer physics.