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Properties study of periodic gratings prepared by electron-beam lithography
Krátký, Stanislav ; Opletal, Petr (referee) ; Matějka, Milan (advisor)
This study examines the process of the relief periodic structures creation by way of electron beam lithography. It describes how to design these structures by means of a computer and subsequently how to create them by electron beam lithograph. Moreover, this study explores the methods by which these structures are measured and evaluated. These methods are used to measure and evaulate binary periodic gratings and thanks to obtained data it can be determined the dependence of the depth of grating on its period. The study also contains measurement of diffraction efficiency on manufactured gratings and comparison of the dependence of its diffraction efficiency on the depth of grating.
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Preparation of contacts to one-dimensional nanostructures
Citterberg, Daniel ; Procházka, Pavel (referee) ; Kolíbal, Miroslav (advisor)
This bachelor thesis deals with methodology of contacting one-dimensional nanostructures. Theoretical part of the thesis defines the concept of one-dimensional nanostructures, then it deals with the potential of their usage, especially in field effect transistors. This part also deals with the possibility of measuring the electrical properties of one-dimensional nanostructures and the possibility of fabricating contacts with sufficiently small sizes using litographic approach. Experimental part gives a brief overview of the tasks that need to be done during the contact fabrication. Subsequently, the individual steps are described in more detail and, finally, initial results of electrical characterization are shown.
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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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Fabrication and testing of microbolometer or other infrared detector based on plasmonic antennas
Děcký, Marek ; Gallina, Pavel (referee) ; Liška, Jiří (advisor)
This bachelor’s thesis is focused on study and fabrication of infrared detectors. Other than just providing a literature research and plasmonics research into the topic, the main goal of this thesis is to propose new designs, manufacturing and characterization such detectors. Specifically the uncooled microbolometer that uses plasmonic antennas for the amplification of the strong coupling which forms between the localized surface plasmons of golden antennas and a phonons of thin dielectric film made from silicon dioxide. The preparation of several types of microbolometers on silicon substrates was conducted using electron beam lithography, photolithography and by thin film deposition techniques. The individual microbolometers differed mainly in the width of the layers between the temperature sensitive meanders and the antennas, but also in the dimensions of the antennas. In the first two sets of microbolometers, the meanders were made from titanium, however meanders in the last set of microbolometers were fabricated from platinum. Reaction of the microbolometers on visible and infrared radiation was tested using measurement of electrical resistance. It was discovered that fabricated microbolometers with titanium meanders significantly reacted on visible light by lowering their resistance. This means they behave like semiconductor. Microbolometers also reacted on infrared radiation by lowering their resistance, but only when temperature of black body source exceeded 400 °C. Reaction on visible and infrared radiation was not observed on microbolometers with platinum meanders with one exception.
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Advanced techniques of micro- and nanosystems fabrication for sensors
Márik, Marian ; Pekárek, Jan (referee) ; Hubálek, Jaromír (advisor)
The use of micro- and nanotechnologies is necessary in the development of advanced sensor systems. In this thesis few selected technologies were studied and tested on fabrication of creating two different systems for bioelectrical and electrochemical applications. For biolelectrical applications a chip with a pair of gold nanoelectrodes was designed and implemented. For electrochemical analysis a novel two electrode system was designed and realized, which should contribute by greater sensitivity and accuracy in amperometric detection compared with three-electrode systems in voltammetric analysis. The fabricated systems were tested and the results were discussed.
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Graphene doping by low-energy electrons
Stará, Veronika ; Kunc, Jan (referee) ; Čechal, Jan (advisor)
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.
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Fabrication of plasmonic antennas for analytical transmission electron microscopy by focused ion beam lithography
Foltýn, Michael ; Kejík, Lukáš (referee) ; Horák, Michal (advisor)
This bachelor thesis is focused on sputtering of thin gold layers and manufacturing of plasmonic antennas using focused ion beam lithography. I optimised the process of sputtering of gold layers by ion beam assisted deposition. Furthermore, I optimised processes connected to manufacturing of plasmonic antennas by focused ion beam lithography. I sputtered thin gold layers 20, 30 and 40 nm thick by various deposition rates. In terms of grain size, the best layers were those deposited with rate of 2 /s. From view of crystallographic composition, the best results were achieved by using deposition rates of 0.2 and 3 /s. I made 3 types of antennas. Rod shaped antennas of 240 nm in length and widths of 40 and 80 nm, and bowtie antenna with 20 nm gap in between its wings. I further optimised parameters of ion etching for each thickness and deposition rate of sputtered layers used for creating antennas mentioned before. The highest quality of antennas was achieved when using layers 20 and 40 nm thick. For manufacturing of bowtie antennas however, layers of all thicknesses deposited by rate of 3 /s were optimal. I discovered, that for layers deposited with rate of 2 /s a lot of redeposited material got sputtered back on to antennas, which can bring the diameters of antennas closer to the desired value at least in one axis.
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Nanoelectrodes for biophysical measurements
Márik, Marian ; Hrdý, Radim (referee) ; Hubálek, Jaromír (advisor)
The aim of the project is formation of nanoelectrodes on the silicon wafer surface by thin-film techniques combined with lithography and nanotechniques developed in LabSensNano. Project is engaged in lithography and in preparation of silicon wafers. Furthermore is proposed a brief proposal of electrodes, proposal of realization and current state of the experiment.
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