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The preparation and characterisation of electrical properties of graphene CVD monocrystals
Hulva, Jan ; Rezek, Bohuslav (referee) ; Mach, Jindřich (advisor)
Chemická depozice grafenu z plynné fáze (CVD) je metoda schopná produkovat grafenové monovrstvy velkých velkých rozměrů. Část experimentální práce v rámci této diplomové práce je zaměřena na depozici a analýzu grafenových monokrys- talů připravených metodou CVD na měděném substrátu. Pro analýu grafénových domén je použito technik optické mikroskopie, elektronové mikroskopie, mikroskopie atomárních sil a Ramanovy spektroskopie. Úkolem další části je studium defektů po- zorovaných na mědi po depozici grafenu pomocí energiově disperzní rentgenové spek- troskopie. Množství těchto defektů bylo odstraněno úpravou depozičního systému ačkoliv takto nebylo dosaženo eliminování všech typů defektů. Poslední část této práce se zabývá měření elektro-transportních vlastností grafenu. Výsledky této části zahrnují měření ve vakuu se zapojeným hradlovým napětím a měření při nízkých teplotách v magnetickém poli.
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Design of manipulator for ultrahigh electron microscope
Caesar, Radek ; Mach, Jindřich (referee) ; Bábor, Petr (advisor)
The main purpose of this thesis is mechanical design of a manipulator for an ultra-high vacuum scanning electron microscope (UHV SEM), being currently developed by TESCAN ORSAY HOLDING a.s. in cooperation with the Institute of physical engineering FME BUT. The manipulator is supposed to be able to handle with specimens in so-called preparation chamber, which the specimens are put in before placing into the analytic chamber. In the preparation chamber the surface finishing and also other operations are made. In the theoretical part some of the technologies used in vacuum engineering, especially various principles of pressure measurement and gas pumping, are described. Besides, the thesis is focused on a brief description of UHV SEM being developed and the methods of specimen preparation. The practical part deals with the concept and the mechanical design of manipulator itself.
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Depositon Ga and GaN nanostructures on graphen substrate
Hammerová, Veronika ; Váňa, Rostislav (referee) ; Mach, Jindřich (advisor)
This diploma thesis is focused on deposition Ga and GaN structures on graphene fabricated by method of mechanical exfoliation. For mechanical exfoliation was used new method with using DGL Gel-Film with kinetically controlled adhesion. Ga is deposited by Molecular beam epitaxy with using eusion cell in UHV conditions. GaN was obtained by post-nitridation of Ga islands. These structures were investigated with optical microscope, SEM, Raman spectroscopy and photoluminiscence.
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Optimization of the Colutron Ion Source
Horký, Michal ; Mach, Jindřich (referee) ; Voborný, Stanislav (advisor)
This bachelor’s thesis concerns with design and assembly of Colutron ion source which produces beam of nitrogen ions with energy from tens to thousand eV. Production of ions and the principle of Colutron ion source is described in the first part. The second part of the thesis is related to the modification and assembly of commercial Colutron ion source. Finally the parameters of the ion beam have been measured for different extraction electrodes and operating parameters in testing apparatus.
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Preparation of graphene layers by MBE
Čalkovský, Martin ; Bábor, Petr (referee) ; Mach, Jindřich (advisor)
This bachelor's thesis deals with growth of graphene by molecular beam epitaxy (MBE). The theoretical section explains the preperation, properties, and detection methods of the material graphene, and the MBE method of graphene preparation is discussed in detail. In the experimental section, optimization of the sublimation carbon source and its properties are shown. Further experiments dealing with the preparation of graphene on Cu and Ge substrates are also described. The presence of graphene structures is proven by Raman spectroscopy.
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Organic materials for molecular quantum bits: deposition and chemical and morphological analysis
Komora, Mojmír ; Mach, Jindřich (referee) ; Čechal, Jan (advisor)
This bachelor thesis deals with an experimental preparation and analysis of ultra thin films of iron phtalocyanines on silicon substrates with goal to describe parameters of films prepared under different conditions, e.g deposition time or substrate temperature. Preparation of samples was done using MBE method under conditions of ultrahigh vacuum in vacuum chamber. Analysis of chemical composition and morfology of prepared films was done with methods of X-ray Photoelectron Spectroscopy, Scanning Electron Microscopy and Atomic Force Microscopy, respectively.
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Graphene-on-silicon Schottky junction solar cells
Zahradníček, Radim ; Drbohlavová,, Jana (referee) ; Mach, Jindřich (advisor)
This diploma thesis concerns itself with fabrication and characterization of Schottky solar cell on the graphene/silicon interface. Schottky solar cells were manufactured using a front collector electrode from gold, silver and carbon. On the graphene/silicon interface of the Schottky solar cell an interlayer of Al2O3 or SiO2. For the purpose of IV characterization of the manufactured Schottky solar cell a measuring apparatus was assembled.
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Preparation of graphene membranes for Ga deposition
Severa, Jiří ; Bartošík, Miroslav (referee) ; Mach, Jindřich (advisor)
This bachelor’s thesis deals with the production of graphene membranes, which would be suitable for the deposition of gallium atoms. In the first part is characterized graphene. The second part is focused on preparation and improvement the production of graphene layers via atomically flat Cu foils. In the third part are described graphene membranes, techniques of their production and specific applications of graphene membranes. The fourth part introduced interface between gallium and graphene layers. The fifth part is the practical part. Graphene was grown on different Cu foils which resulted in higher quality graphene grown on smooth foils. Subsequently, the production of graphene membranes and deposition of gallium atoms were done.
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Optimization of thermal dissociation atomic hydrogen source for use SEM
Melichárek, Václav ; Polčák, Josef (referee) ; Mach, Jindřich (advisor)
The focus of this bachelor's thesis is the optimization of a thermal dissociation monoatomic hydrogen source. The project entailed the design and construction of a new control electronics for the thermal dissociation source, because the source has been powered using universal laboratory power supplies until now. The thesis begins with a brief introduction into the interaction of graphene with monoatomic hydrogen, the operational principle and construction of the monoatomic hydrogen source. Furthermore, the requirements on the design of the electronics are specified. A more detailed analysis of possible solutions, and the selection of the optimal solution were also conducted. The practical part discusses the conceptual designs in detail and describes the selection of the optimal solution. It follows by elaborating on the implementation of the control electronics in detail, its design and construction, and the electrical circuit in particular.
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Preparation of SiN ultrathin films
Dvořák, Martin ; Voborný, Stanislav (referee) ; Mach, Jindřich (advisor)
This bachelor´s thesis deals with design, testing and calibration of an effussion cell generating silicon atomic beam having thermal energy (0,1 - 1 eV). These beams are used for the preparation of Si and SiN ultrathin films. Silicon nitride and its applications in semiconductor industry are reviewed. First experiments with deposition of ultrathin films of Si and SiN are described. These layers have been analyzed by x-ray photoelectron spektroscopy (XPS) and atomic force microscopy (AFM).
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