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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Vyhodnocení vlastností fotovoltaických článků s optickými koncentrátory / Evaluation of photovoltaic cells with optical concentrators

Pončík, Vlastimil January 2011 (has links)
This work deals about the photovoltaic systems, especially with concentration of the sunlight in use of concentrators that are placed direct on the panel. Concentrated photovoltaics systems employ sunlight concentrated onto photovoltaic surfaces for the purpose of more efficient electrical power production. A photovoltaic cell with concentrator includes difractive optical elements that concentrate light on a photovoltaic chip Flat polycarbonate optical element has difractive gratings on its surface.
12

Příprava a použití exfoliovaných grafitových/grafenových vrstev v oblasti nanosenzoriky / Preparation and Utilization of Exfoliated Graphite/Graphene Layers in Nanosensorics

Hrabovský, Miloš January 2014 (has links)
Tato diplomová práce se věnuje výrobě vrstev grafitu/grafenu a meření jejich transportních vlastností v závislosti na relativní vlhkosti. Grafenové šupinky byly nanášeny pomocí mechanického odlupování . Pro kontaktování grafenových šupinek byla využita elektronová litografie a na pozorování byly využity optická mikroskopie, mikroskopie atomárních sil a elektronová mikroskopie. V práci jsou popsány jednotlivé kroky výroby, analýzy a měření transportních vlastností nanesených grafenových šupinek.
13

Vodíkem modifikované grafenové struktury pro polem řízené tranzistory / The hydrogen modification of the graphene structures for field effect transistors

Kurfürstová, Markéta January 2016 (has links)
This master’s thesis is focused on the subject of graphene modified with atomic hydrogen and its electronic transport properties. Structural and electronic properties of graphene and hydrogenated graphene are compared in the theoretical part of the thesis. The Raman spectroscopy technique is described, including characterization of typical Raman spectra of both unmodified and modified graphene. Samples used during experimental part of the thesis are prepared via laser and electron lithography, and are set to be measured in a vacuum chamber. Subsequently, electronic transport properties are measured before and after hydrogen modification of graphene. Finally, hydrogenated graphene is irradiated using electron beam and changes in its structure are analyzed with Raman spectroscopy techniques.
14

In-situ mapování rozložení náboje a transportní odezvy nanostruktur připravených pomocí rastrovací sondové mikroskopie na grafenových Hallových strukturách / In-situ mapping of charge distribution and transport response of nanostructures fabricated by scanning probe microscopy on graphene Hall bars

Přikryl, Vojtěch January 2019 (has links)
Graphene is a material suitable for electronic applications including sensors and biosensors operating in atmospheric conditions and at varying relative humidities. This work concerns the charge diffusion in Hall bar shaped graphene based field effect transistor that is simultaneously investigated by Kelvin probe force microscopy and macroscopic transport measurement. Furthemore it studies the possibilities of graphene Hall bar modification by local anodic oxidation, local cathodic hydrogenation and mechanical lithography.
15

Studium vlastností povrchových plazmonových polaritonů na magnetických materiálech / Study of Properties of Surface Plasmon Polaritons on Magnetic Materials

Dvořák, Petr January 2011 (has links)
The diploma thesis deals with the experimental study of surface plasmon polaritons (SPPs) on nano-structures with the Au/Co/Au multilayer. Plasmonic structures were prepared by the electron beam lithography and by the focused ion beam. A Scanning optical near-field microscope was used for detection of surface plasmon polaritons. SPPs were confirmed by the experiment with different polarizations of the illuminating light. Furthermore, differences in plasmon interference wavelengths was measured for different surface dielectric functions. Finally, the decantation of the SPPs interference image was measured in dependence on the external magnetic field.
16

Příprava grafenových vrstev pokrytých Ga atomy a charakterizace jejich elektrických vlastností / The preparation of graphene layers modified by Ga atoms and characterisation of their electrical properties

Piastek, Jakub January 2015 (has links)
This master's thesis deals with the study of electric properties of graphene layers covered by Ga atoms in UHV conditions. The substrates were prepared by using laser litography and the graphene layer was prepared by using chemical vapor deposition (CVD). Dependence of Dirac point location on gallium atoms deposition time and influence of electrical properties of graphene on hydrogen atoms deposition time were studied. Experimental results and their evaluation are discussed.
17

Elektrostatické vychylovací a korekční systémy / Electrostatic Deflection and Correction Systems

Badin, Viktor January 2015 (has links)
The aim of this master's thesis is to explore and study dynamic aberration correction options in electron-beam lithography systems. For the calculations, the thesis uses the optical column of the BS600 electron-beam writer. The thesis focuses on corrections of the third order field curvature, astigmatism, and distortion aberrations of the currently used magnetic deflection system and a newly designed electrostatic deflection system. The parameters of the two deflection and correction systems were compared.
18

Selektivní růst GaN nanostruktur na křemíkových substrátech / Selective growth of GaN nanostructures on silicon substrates

Knotek, Miroslav January 2015 (has links)
This thesis deals with deposition of gallium nitride thin films on silicon substrates covered by negative HSQ rezist. Rezist was patterned via electron beam lithography to create masks, where the selective growth of crystals was achieved. Growth of GaN layers was carried out by MBE method. For achievement of desired selective growth, the various deposition conditions were studied.
19

Tvorba nanostruktur a nanosoučástek pro oblast nanoelektroniky a spintroniky / Fabrication of Nanostructures and Nanodevices for Nanoelectronics and Spintronics

Lišková, Zuzana January 2015 (has links)
The thesis deals with preparation of graphene nanostructures and their applications in the measurement of transport properties of graphene. The contacts for measurement of resistance are fabricated by electron beam lithography on graphene exfoliated flakes, CVD graphene layers and grains. Graphene is also shaped using the same method. Resistivity of the layer, concentration and mobility of charge carriers are determined by different approaches. Hysteresis appearing in dependence of resistivity on the gate voltage is discussed as well. A significant part of the work is dedicated to monitoring the response of graphene resistance to relative humidity changes and potential use of graphene as a sensor of relative humidity.
20

Technologie přípravy hlubokých struktur v submikronovém rozlišení / Submicron Structures with Deep Relief — Technology of Preparation

Matějka, Milan January 2017 (has links)
The dissertation thesis is focused on research and development in the field of microfabrication by the technology of electron beam lithography. In the first part of this work, the extensive study is conducted in the field of technology of electron beam lithography in terms of physical principles, writing strategies and resist materials. This is followed with description of physical principles of etching for the transfer of relief structures into substrates. The thesis describes innovative techniques in modelling, simulation, data preparation and optimization of manufacturing technology. It brings new possibilities to record deep binary or multilevel microstructures using electron beam lithography, plasma and reactive ion etching technology. Experience and knowledge in the large area of microlithography, plasma and anisotropic wet-etching of silicon have been capitalized to the design process of manufacturing of nano-patterned membranes. It was followed with practical verification and optimization of the microfabrication process.

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