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Photoluminiscence study of thin layers of MoS2
Kuba, Jakub ; Kunc,, Jan (referee) ; Bartoš, Miroslav (advisor)
The thesis deals with study of thin layers of transition metal dichalcogenides, especially of molybdenum disulfide. Nanostructures were fabricated on two-dimensional crystals of MoS2 and WSe2. Within followed analysis attention was paid to the photoluminescence properties. In the thesis transition metal dichalcogenides are reviewed and description of the modified process of preparation by micromechanical exfoliation is given.
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Inovation of measurement equipment used for analyzing of photovoltaick cells
Otépka, Jakub ; Bača, Petr (referee) ; Vaněk, Jiří (advisor)
This bachelor thesis deals with the design of a tachometer which is used to measure and display of mechanical aperture speed of a measuring equipment for the defect analysis of solar cells using the photoluminescence method. This work is divided into three parts. The first section describes the principle of solar cells, the principle of luminescence radiation and its types. Next the defects of solar cells are analyzed. The second part discusses the theory of tachometers, the principles and methods of loading pulses. The third part is then analyzed the design and construction of the selected type tachometer.
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Electrochemical etching of silicon
Vrzal, Pavel ; Voborný, Stanislav (referee) ; Šamořil, Tomáš (advisor)
The electrochemical etching is very used technique for semiconductor materials modification. Different structures which find applications in many fields (biotechnology, nanotechnology or electronics) can be prepared by this technique. The task of bachelor’s thesis was preparation of porous silicon using electrochemical etching. At first, a study dedicated to porous Si was carried out. Experimental part of this work deals with a design of etching cell which was used for preparation of porous silicon by electrochemical etching. In addition, the porous Si was prepared by metal assisted chemical etching. Subsequently, created structures were analyzed by scanning electron microscopy. Photoluminescence properties of porous silicon were studied as well.
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Plasmon enhanced photoluminescence
Édes, Zoltán ; Kůsová,, Kateřina (referee) ; Šikola, Tomáš (advisor)
Diplomová práce se zabývá fotoluminiscencí polovodičových materiálů zesílené plazmonovými polaritony. Je popsána základní teorie interakce mezi lokalizovanými povrchovými plazmonovými polaritony a fotoluminiscenčními látkami. Dva mechanismy, které mohou vést k fotoluminiscenci zesílené plazmonovými polaritony jsou diskutovány. Následně je popsán návrh aparatury pro měření fotoluminiscence a způsob její realizace. Funkčnost aparatury je ověřena měřením fotoluminiscenčních spekter objemového GaN, nanokrystalického Si a CdTe kvantových teček. Nakonec je zkoumána metoda přípravy vzorků sestávajících z kovových nanokuliček a fotoluminiscenčně aktívních CdTe kvantových teček.
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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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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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Diagnostic method of solar cells operating at very low temperatures
Bartoň, Jiří ; Stojan, Radek (referee) ; Veselý, Aleš (advisor)
This work deals with the modern diagnostic methods of defects detection of solar cells. Defects are detected by electroluminescence and photoluminescence methods. The main focus of this work is an innovation workplace for measuring solar cell defects at very low temperatures using photoluminescence. Liquid nitrogen is used to cooling solar cells. By using low temperatures can be detection methods to obtain more objektive results of diagnostic defects.
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The equipment for control very low temperatures during the detection defects of solar cells
Stojan, Radek ; Bača, Petr (referee) ; Vaněk, Jiří (advisor)
This work deals with measuring of very low temperatures during the detection defects of solar cells by photoluminescence method. Liquid nitrogen is used to cooling solar cells. Properties of liquid nitrogen and safety of handling are described in this work. Themperature in cryo area is measured by the thermocouple senzors. A main part of this work was to concept and creation of equipment for themperature controling in cryo technique. This equipment signalling danger scorch in low temperatures. The device was created to complement work place for the detection defects of solar cells by photoluminescence method.
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Photoluminescence diagnostic method with transmission illumination
Kafka, Martin ; Veselý, Aleš (referee) ; Vaněk, Jiří (advisor)
The aim of this diploma thesis is an innovation of photoluminescence measure research workplace for measurement of cells structure defects by method of transmissive illumination while employing the current methods of measurement of defect in the solar cells structure. The first part deals with explanation of historical development of solar energy, of how we can reach production of electric power with contribution of solar radiation and defines usability of solar cells in practice. The thesis further analyses a practical application of measurement via laboratory diagnostic methods used by Department of Electrotechnology Brno University of Technology. The second part is focused on mechanical design of experimental photoluminescence measure workspace used for quick diagnostic defects employing the rear arousing source for detection of defects with assistance of transmissive system of illumination. Finally, with co-operation of SOLARTEC s.r.o. three types of solar cells are measured by this new method and compared with results of measurement via diagnostic methods of LBIV (Light Beam Induced Current), LBIC (Light Beam Induced Voltage), Electroluminescence, Photoluminescence, and detection defects by radiation of Microplasma.
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Solar cells photoluminescence defect detection methods
Vala, Zbyněk ; Veselý, Aleš (referee) ; Vaněk, Jiří (advisor)
This thesis discusses modern methods for fast defect detection of solar cells. For the means of the defect classification, the technological production process of crystalline silicon solar cells is described. The defects are researched by the electroluminescence and prohtoluminescence methods. The Photoluminiscence method is improved by the posibility of using different wavelenght of excitacion sources. The range of using in industrial production is determined for the discussed methods.
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