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Dynamic testing of solar cells
Šneidr, Radim ; Hégr, Ondřej (referee) ; Boušek, Jaroslav (advisor)
The content of this thesis is the validation of the method of dynamic testing of solar photovoltaic cells. Testing methods for determining the parameters of the photovoltaic cell replacement scheme has been verified through testing a set of crystalline silicon photovoltaic cells. To accelerate the diffusion capacity measurement and to improve reproducibility of the measurement we propose new method of determining the time constant for diffusion capacitance using a combination of two short pulses. For this method of measurement new scheme for dynamic tester timing has been proposed and implemented.
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Diagnostics of passivation layers for crystalline silicon solar cellls.
Sládek, Karel ; Hégr, Ondřej (referee) ; Boušek, Jaroslav (advisor)
The work deals with a comparison of existing and perspective types of passivation and anti-reflective coating for silicon solar cells. The theoretical part describes the appropriate methodology for the characterization of these layers and focuses on the passivation layers based on Al2O3. The practical part describes design and verification operations of the equipment for measuring of the amount of fixed charge in the passivation layers using corona discharge. It also describes the implementation of equipment and the results of indicative tests for positive and negative polarity of high voltage. The final part discusses the possibility of equipment improving.
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Elimination of defects in Si substrates by Rapid Thermal Process application
Frantík, Ondřej ; Hégr, Ondřej (referee) ; Szendiuch, Ivan (advisor)
Low cost, rapid and high thermal by IR heating, rapid cooling and high efficiency, there are RTP (Rapid Thermal Processing) properties. We can use RTP for annealing, diffusion, contacting, oxidation and others. Rapid temperature change and IR heating can be followed positive effects in the silicon substrate. This paper is focused on annealing by RTP. Wafers were p-type monocrystalline CZ silicon with different bulk minority carrier lifetime. Minority carrier lifetime was measured by MW-PCD (Microwave Photoconductance Decay) before and after thermal processing.
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Study of organic based structures for solar cells
Kostovčík, Tomas ; Hégr, Ondřej (referee) ; Boušek, Jaroslav (advisor)
Práce se zabývá problematikou využití organických materiálů v solárních článcích. V úvodu práce jsou rozebrány a vysvětleny jednotlivé fyzikální a chemické jevy, které ovlivňují vlastnosti organických materiálů. Práce pokračuje rozborem působení rozličných struktur organických solárních článků na jejich vlastnosti. Dále je popsána technologie výroby vzorku a jsou v ní uvedeny výsledky měření fotovodivosti.
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Case studies for statistical data analysis
Chroboček, Michal ; Hégr, Ondřej (referee) ; Novotný, Radovan (advisor)
This thesis deals with questions which are related to the creation of case studies for statistical data analysis using applied computer technology. The main aim is focused on showing the solution of statistical case studies in the field of electrical engineering. Solved case studies include task, exemplary solution and conclusion. Clarity of explained theory and the results understanding and interpretation is accentuated. This thesis can be used for practical education of applied statistical methods, it’s also supplemented with commented outputs from Minitab. Trial version of Minitab has been used for solution of case studies.
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Worpllace for dynamic testring of solar cells.
Hanák, Kamil ; Hégr, Ondřej (referee) ; Boušek, Jaroslav (advisor)
This work deals with method for characterization of photovoltaic solar cells based on evaluation of solar cell response to fast transients. The voltage of the cell in both forward and reverse polarisation was controlled by current pulse exciting. Real reverse breakdown voltage and exact value of serial resistance of the cell can be obtained easily by evaluation of the transient curves recorded by digital osciloscope. By negotiation of the time constants of the cell response to excitation in forward polarisation the lifetime of minority carriers in semiconductor bulk can be estimated.
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Chemical passivation of surface for silicon solar cells
Solčanský, Marek ; Hégr, Ondřej (referee) ; Boušek, Jaroslav (advisor)
This master´s thesis deals with an examination of different solution types a for the chemical passivation of a silicon surface. Various solutions are tested on silicon wafers for their consequent comparison. The main purpose of this work is to find optimal solution, which suits the requirements of a time stability and start-up velocity of passivation, reproducibility of the measurements and a possibility of a perfect cleaning of a passivating solution remainig from a silicon surface, so that the parameters of a measured silicon wafer will not worsen and there will not be any contamination of the other wafers series in the production after a repetitive return of the measured wafer into the production process. The cleaning process itself is also a subject of a development.
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Lifetime measurement of current carriers in silicon solar cells structures
Macháček, Martin ; Hégr, Ondřej (referee) ; Boušek, Jaroslav (advisor)
This thesis deals with a lifetime measurement of current carriers in silicon solar cell structures. In the first chapter there is a description of several recombination models and their participation at a final effective lifetime value. By using these recombination models in a computer simulation it is possible to receive approximate evaluation of some important silicon solar cell structure parameters. The PC1D simulation program was used for this thesis. For the lifetime measurement of real test-wafers two methods were used: QSSPC (quasi-steady-state photoconductance) and MW-PCD (microwave photoconductance decay). There is a detail description of these methods, used measurements machines and differences between both of them in the chapter four. The main objective of the thesis is mentioned in the last chapter, which is mainly focused on a chemical passivation of silicon wafers and deals with a problem of post-passivation wafer cleaning. There are three passivation techniques mentioned: the iodine in ethanol solution, the iodine and polymer in ethanol solution and the quinhydron in methanol solution. In two cases a results, that are adequate to return the tested wafers in the manufacture process, were achieved.
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