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Study of interface graphene-on-silicon by EBIC method
Hammerová, Veronika ; Lišková, Zuzana (referee) ; Mach, Jindřich (advisor)
This bachelor thesis is dedicated to study of interface graphene-on-silicon located on solar cell with graphene layer. The interface was studied by EBIC method and Raman spectroscopy. Solar cells with graphene sheet was fabricated using electron litography, chemical etching and graphene made by CVD method. The thesis describes fabrication of solar cells with graphene layer, method EBIC measured on SEM and analysis of changes graphene-on-silicon interface caused by enlightenment electron beam by Raman spectroscopy. In theorethical part is described p-n junction and Schottky junction of solar cell, graphene and its fabrication, as well as EBIC method fundamentals.
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Schottky solar cells with interface graphene/Si modified by gallium
Hlavička, Ivo ; Lišková, Zuzana (referee) ; Mach, Jindřich (advisor)
Main focus of this bachelor thesis is on fabrication, characterization and modification of graphene-on-silicon Schottky solar cells. By transfering CVD graphene onto silicon wafer with electrodes, a basic Schottky junction was created. The junction was then modified by annealing in UHV chamber as well as by gallium deposition. Information about power conversion efficiency of such Schottky solar cells was then obtained by IV measurement. Schottky junction itself was analyzed using X-EBIC method.
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Fabrication of Nanostructures and Nanodevices for Nanoelectronics and Spintronics
Lišková, Zuzana ; Červenka, Jiří (referee) ; Čech, Vladimír (referee) ; Šikola, Tomáš (advisor)
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.
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Preparation of graphene nanostructures for applications
Dubnická Midlíková, Jana ; Procházka, Pavel (referee) ; Lišková, Zuzana (advisor)
The thesis deals with preparation of graphene nanostructures and their applications in the measurement of electrical transport properties of graphene. Graphene layers are prepared by mechanical exfoliation in two ways, by using adhesive tape or elastomeric film. The contacts for measurement of graphene layers resistance are fabricated by electron beam litography on exfoliated graphene flakes. Measurements of graphene transport properties take place in two environments, in air and in vacuum. Mobility and concentration of charge carriers of prepared graphene nanostructure are determined from the measured values.
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Analysis of the transport properties of graphene nanostructures
Novák, Martin ; Bartošík, Miroslav (referee) ; Lišková, Zuzana (advisor)
Graphene transport properties are analysed in this thesis. They are strongly dependent on doping with charge carriers. The number of charge carriers can be influenced by electric field, substrate or surface adsorbates. The graphene field-effect transistor (FET) has been prepared. Graphene made by chemical vapor deposition (CVD) has been con tacted through gold structures made by electron beam lithography (EBL). Dependences on electrode configuration, gate voltage and used substrate are observed.
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Preparation of graphene layers by various methods and characterization of their properties
Zahradníček, Radim ; Bartošík, Miroslav (referee) ; Lišková, Zuzana (advisor)
This bachelor's thesis deals with the production of graphene by different methods. Graphene was prepared by mechanical exfoliation and chemical methods. Graphene oxide (GO) was first prepared by modified Hummers method and disolved the solution in isopropyl alcohol. It was subsequently reduced by photoreduction, UV radiation and thermal reduction. Produced graphene samples were characterized using optical microscopy, electron microscopy, atomic force microscopy, Raman spectroscopy and X$-$ray photoelectron spectroscopy. Measurement results and evaluation of production quality of graphene are shown in this work.
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Aplication of SPM in study and modification of ultrathin films Pt, Co and graphene
Lišková, Zuzana ; Červenka,, Jiří (referee) ; Bartošík, Miroslav (advisor)
This diploma thesis deals with the preparation of the very thin films and their investigation by scanning probe microscopy methods. The ultrathin films of Pt on Pt(111) were created by pulsed laser deposition and the ultrathin films of Co on Pt(111) were deposited by thermal evaporation. The coverage of the substrate was much smaller than one monolayer (in order of hundredths of monolayer). The nucleation theory was verified by these experiments using so-called Onset method. Further graphene sheets were prepared on layer of Si/SiO2 by the mechanical exfoliation from the graphite crystal. The fabricated graphene sheets were studied by micro-Raman spectroscopy, microreflectometry, atomic force microscopy and similar techniques. These methods proved the thinnest graphite layers were consisted of two graphene monolayers.
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Transport Properties of Graphene Layers during Their Transfer
Gryga, Michal ; Lišková, Zuzana (referee) ; Procházka, Pavel (advisor)
This bachelor thesis is focused on the measurement of the transport properties of graphene, which was produced by chemical vapor deposition (CVD) method on a copper foil and subsequently transferred onto a silicon substrate covered by 280 nm of silicon dioxide. In this work we studied an influence of different types of copper etchants and influence of plasma cleaning of silicon substrates prior to the graphene deposition.
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