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Measurement of spectral characteristics in Labview environment
Konečný, Dávid ; Hégr, Ondřej (referee) ; Boušek, Jaroslav (advisor)
This work deals with design of a program for measurement of characteristics luminescence of inorganic semiconductors in LabView environment. After understanding with theoretic part a program for automated measurements was made including two type of measurements option. The program for measurement of Volt-Ampere characteristics by given wave length and for measurement of current on wave length dependencies is presented.
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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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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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Intelligent control of train track model
Prokš, Jiří ; Hégr, Ondřej (referee) ; Pavlík, Michal (advisor)
The aim of this thesis is design of elements intelligent control of train track model. The first part of the thesis is focused on principle of data communication. It explains what it is data communication and how it works out. Practical part of the thesis is focused on designe of communication. Data communication is realized by infrared radiation. Practical part describes the funcional parts of system and their design, such as: control part, receiver and transmitter, switching elements and h-bridge. Properties of elements specialize for model of railway are considered in design. Summary of the design’s parameters, use, advantages and disadvantages are described at the end of this thesis.
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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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Thermal stability of sputtered yttrium oxide layers
Kršňák, Jiří ; Boušek, Jaroslav (referee) ; Hégr, Ondřej (advisor)
This work deals with behavior of deposited yttrium oxide thin film after heat stress. Within solution thin yttrium oxide films were deposited at silicon substrates, which were exposed to various cycles of heat stress. Tested structures were investigated before and after heat stress in term of surface topography stability with the hepl of electron microscopy.
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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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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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