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Analyse of photovoltaic solar cells by the photoluminescence method
Baura, Tomáš ; Bača, Petr (referee) ; Vaněk, Jiří (advisor)
This thesis deals with the analysis of solar cells by photoluminescence method. Photoluminescence method is based on the excitation of luminescence radiation of the solar cell material by an external excitation light source. This method can detect various types of defects in the material solar cells. The main objective is the design and realization of a measuring system defects of solar cells, which is based on this method. For excitation of luminescence is used LED array. For the detection of luminescence is used CCD camera with IR optical filter. To filter out the excitation light radiation is used disc screen and optical interrupter. The parameters and options of this measuring system are verified and characterized by test measuring for example the achievable rotation speed of screen and response of optical interrupter. At the end is tested detection of luminescence radiation of solar cells in the measuring system. The measured images are compared with the method of electroluminescence.
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Preparation of sample cross-sections and analysis by SIMS
Karlovský, Juraj ; Pechal, Radim (referee) ; Bábor, Petr (advisor)
This thesis studies possible methods of semiconductor sample measurement by SIMS, with emphasis on testing different measurement parameters and sample preparation. Part of this master thesis deals with the design of a modified sample holder compatible with the used ToF-SIMS$^{5}$ instrument, IONTOF company, which is capable of tilting the sample by defined angle. This holder enables sample preparation in the main chamber of the instrument without the need of transferring the sample between instruments, which limits the probability of sample contamination. This sample holder was tested by ion machining of TIGBT sample edge and by imaging of a crater edge, created in previous measurement. Edge termination structures prepared by different techniques were measured on the TIGBT samples. Further measurements with the goal of optimizing the depth resolution for thin layers were done on Molybdenum-Silicon-multilayer X-Ray Mirror. Part of the measurements was focused on comparing depth profiles measured at low temperatures. For these measurements the samples with Indium multilayers in GaN substrate were used.
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Printed photoelectrochemical UV sensor
Vrbková, Kateřina ; Syrový, Tomáš (referee) ; Dzik, Petr (advisor)
This paper deals with the sensors, designed for ultraviolet light detection. There are many options in UV sensors construction. But in any case, there is a semiconducter used as a sensitive component. The most common photocatalyst is titanium dioxide. In electronic it is mainly used due to its suitable physical and chemical properties and good chemical stability. The aim of the work is preparation of gel electrolyte, which can close the electrical circuit between cathodic and anodic compartment and allows the passage of electrons. The hole first chapter is divoted to methods of UV sensors production, including electrochemical method on which is based our sensor.
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Monocrystalic silicon - optical properties
Kahánek, Tomáš ; Vaněk, Jiří (referee) ; Špinka, Jiří (advisor)
This diploma thesis deals with optical properties of silicon. The main task of the work was to create silicon samples with ohmic contacts. Suitable radiation source was designed to measure absorption edge of monocrystalline silicon. Designed measuring station was realised. Measurements were performed on samples of p-type monocrystalline silicon provided by ON Semiconductor Rožnov. p. Radhoštěm. The absorbtion edge was measured.
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Photovoltaic systems in the cities
Dobiáš, Pavel ; Procházka, Zdeněk (referee) ; Mastný, Petr (advisor)
This Bachelor thesis' main goal is to introduce a potential reader with the photovoltaic system questions and its utilization in many applications. In the leading chapter the thesis deals with the potential of the energy which is radiated from the Sun towards the Earth. It tries to analyze the common problems of using this energy. The next part deals with simple semiconductor operating principles and explain the principles of photovoltaic cell functions. The upcoming part deals with the construction and basic types of photovoltaic cells and show the possible ways in their development. In the next part there are analyzed many types of photovoltaic systems and their application in praxis. In the next part the reader is introduced with the meaning of photovoltaic as a renewable source and with its support in the European Union and Czech Republic. The last part deals with design of four devices which uses photovoltaic system as a power source and which can be used in the city agglomeration environment.
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Characteristics features of luminescence radiation solar cells
Malý, Martin ; Šimonová, Lucie (referee) ; Stojan, Radek (advisor)
This thesis deals with characteristic features of luminiscence radiation solar cells during electroluminiscence. Electroluminescence is the process in which a substance begins to radiate electromagnetic radiation (luminiscence radiation) due to passing electrical current. Various defects in the structure of the photovoltaic cell can cause polarization of that radiation. The aim of this thesis is to measure some polycrystalline solar cells by electroluminescence. Selected solar cell is measured by electroluminescence extended by polarizing filter and afterward collected data are processed in MATLAB.
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Computer modeling of MOSFET transistor
Major, Jan ; Harwot, Ondřej (referee) ; Pokorný, Michal (advisor)
Work is focused on computer modeling of PN junction and MOSFET transistor in the program COMSOL Multiphysics and in program TiberCAD. The text is discussed on the drift and diffusion in semiconductors. Also shown is a method of modeling the PN junction and MOSFET transistor in the programs and compare models.
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Plasmochemical treatment of substrates and coatings in R2R arrangement
Patakyová, Sylvia ; Homola,, Tomáš (referee) ; Dzik, Petr (advisor)
This bachelor thesis deals with the comparison of the properties of two titanium dioxide types, which is due to its semiconductive properties commercially used in photoactive layers. The main reason for comparing these sources is their different price which can have possible impact on industrial use. Photoactive layers formed by various wet deposition techniques are cured by atmospheric plasma. The effect of plasma on individual depositions is investigated by electroanalytical methods. Voltametric and chronoamperometric characteristics indicate the dependence of the substrate activity on the time or distance of plasma treatment. Surface of composites were scanned by SEM and the mutual surface properties of untreated composites and the effect of siloxane binder on them were analyzed.
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Analyse of photovoltaic solar cells by the photoluminescence method
Richter, Vladimír ; Bača, Petr (referee) ; Vaněk, Jiří (advisor)
This diploma thesis deals with the issues of photovoltaic cells. The main aim of this thesis is to introduce the principles of operation of solar cells and methods of detection of defects affecting their quality. The first part is about the functional properties of silicon cells and it also examines the possibilities of detecting the defects of these structures. It also describes the most commonly used modern diagnostic methods. In the next part, practical tests of photovoltaic cells using the methods electroluminescence and photoluminescence are performed. These methods are based on the excitation of luminescence radiation of the silicon material by the external light source.
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