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Transparent and semi-transparent thin films for bioelectronics
Jarušek, Jaromír ; Fohlerová, Zdenka (referee) ; Gablech, Imrich (advisor)
This thesis is focused on the development of transparent microelectrode arrays for bioelectronic interfaces with electrogenic cells. The main area of interest is in vitro applications suitable for the observation of living cells using an inverted optical microscope. The theoretical part further discusses different types of transparent and semitransparent electrically conductive materials including gold-based thin films, titanium nitride, carbon-based layers, conductive oxides, and conductive polymers. The experimental part is focused on the process optimization of indium tin oxide (ITO) magnetron sputtering and stressing of TiN-ITO thin films using chemical and electrochemical techniques. The last part is focused on the design, manufacturing, and testing of planar microelectrode arrays made of different electrode materials.
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Microfluidic systems in silicon technology
Juránek, Dominik ; Fecko, Peter (referee) ; Gablech, Imrich (advisor)
This thesis is devoted to the topic of microfluidics and the functionality of microfluidic devices when working with blood. It further focuses on the use of microfluidic devices to cut blood cells. The first part of this work is dedicated to the theoretical background of microfluidics, it briefly introduces the history of microfluidic devices and the materials used for their integration, moreover, it talks about the methods used when constructing a microfluidic device in a silicon substrate. Lastly, this section includes a description of blood and its composition and some properties important for working with microfluidic devices. The practical part is concerned with the (manufacturing procedure of) creating a microfluidic and testing of device that can cut red blood cells.
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Design, fabrication and testing of graphene biosensors
Tripský, Andrej ; Gablech, Imrich (referee) ; Bartošík, Miroslav (advisor)
Pokrok ve vývoji nanotechnologií nám poskytuje dobrou příležitost k vývoji nových špičkových zařízení. Tato práce si klade za cíl vyrobit, popsat a změřit grafenové pH senzory na dvou různých substrátech - polymeru parylenu C a SiO2. Tento pH senzor je prvním krokem ve vývoji nositelné náplasti monitorující stav kůže a možné infekce. Grafen je 2D materiál na bázi uhlíku se zajímavými vlastnosti a nadějnými aplikacemi. Úspěšně jsme provedli dva různé experimenty sloužící k charakterizaci grafenových senzorů a jejich odezvu na různé hodnoty pH. V prvním experimentu jsme použili horní elektrolytické hradlo k určení bodu neutrality (Diracův bod). Druhý experiment popsal změnu rezistence grafenu jako funkce pH. Dále jsme také funkcionalizovali grafen polyanilinem, abychom zlepšili jeho vlastnosti. Prokázali jsme citlivost grafenových senzorů na pH pro oba substráty a objevili jsme několik výzev jako potřebu kontroly iontové síly, experimentů samotných a destrukce grafenu.
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MEMS based energy harvesting
Klempa, Jaroslav ; Prášek, Jan (referee) ; Gablech, Imrich (advisor)
This work is dedicated to principles of energy harvesting or scavenging from free energy around us. Energy harvesting principles are described in the first part. Following chapter is devoted to description of piezoelectricity and piezoelectric materials. Next part researches already reported results on piezoelectric energy harvesters. Following chapter shows simulations on designed structures in ANSYS® Workbench. Next the fabrication of the structures is described. Measurement are made regarding to maximum generated power.
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Sputtering of nitride layers using Kaufman ion-beam source for bioelectronics applications
Jarušek, Jaromír ; Chmela, Ondřej (referee) ; Gablech, Imrich (advisor)
In this work, nitride layers, their applications in bioelectronics, and methods of chemical vapour deposition and physical vapour deposition are presented. The focus of this work is the preparation of titanium nitride thin films by reactive sputtering using Kaufman ion-beam sources. Thin films were deposited on silicon wafers and microslides. Deposited titanium nitride thin films are characterized by X-ray diffraction, four-point probe sheet resistance measurement and profilometry to determine residual stress.
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Tin dioxide based semiconducting gas sensors
Gablech, Imrich ; Pytlíček, Zdeněk (referee) ; Prášek, Jan (advisor)
This project is aimed at semiconductive gas sensors based on tin dioxide. In the first part, gas sensors are divided depending on their principal of functionality. Next part is about functionality of tin dioxide gas sensors and the possibilities of active layer modification. Experimental describes gas sensor from its drawing until construction, testing and characterization. Several microelectronic technologies such as thin-film, thick-film, LTCC, spray-coating or wire-bonding were used for constructing the sensor. In the last part properties of gas sensors and differences in functionality between modified and unmodified gas sensor are summarized.
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Electrode system of thick-film electrochemical sensors optimization
Gablech, Imrich ; Adámek, Martin (referee) ; Prášek, Jan (advisor)
This thesis is about optimization of three-electrode electrochemical sensor for detection of substances in solutions fabricated using standard thick film technology. The theoretical part of this thesis describes the thick film technology, introduction to electrochemistry and electro analytical methods for the detection of substances in solutions. The surface optimization of reference and auxiliary electrode of a three-electrode system is solved in the practical part. In conclusions results of the evaluation and description of the ideal three-electrode system are discussed.
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Characterization of graphene electrical properties on MEMS structures
Brodský, Jan ; Pekárek, Jan (referee) ; Gablech, Imrich (advisor)
This work presents basic properties of graphene, methods for its synthesis and methods for its characterization by Raman spectroscopy, two-point probe, four-point probe and van der Pauw measurements. The experimental part of this work describes the process of graphene oxide, reduced graphene oxide and graphene sample preparation and measurement of its current-voltage characteristic by two-point probe method. Subsequently, sample annealing in vacuum furnace is described in this work. The annealing is important for acquiring good electrical contact between the 2D material and electrodes. Sample analysis by Raman spectroscopy is performed. The last chapters of this work describe design and fabrication of MEMS structure. Such structure serves for characterization of graphene and other 2D materials.
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Piezoelectric MEMS resonators for sensing applications
Klempa, Jaroslav ; Svatoš, Vojtěch (referee) ; Gablech, Imrich (advisor)
Basic principles and processes used during fabrication of microelectromechanical systems are presented in this work. This thesis is focused on material properties, deposition, lithographic and micromachining processes. Fundamental principles and applications of piezoelectric resonant structures are described as well. Final part of this work is devoted to simulation of resonant beams using FEM method in ANSYS® Workbench, practical fabrication and characterization of piezoelectric MEMS resonators.
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