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Diagnostic of semiconductor materials by EBIC method
Davidová, Lenka ; Máca, Josef (referee) ; Čudek, Pavel (advisor)
Master´s thesis is focused on diagnostics of semiconductor materials by EBIC method (measuring of currents induced beam), determination of the lifetime of minority carriers, or their diffusion length. The theoretical part is aimed at the principle of scanning electron microscopy, the characteristic properties of the microscope and the signals generated by the interaction of the primary electron beam with the sample. The thesis describes a structure of semiconducting silicon, band models, types of lattice defects and doped of semiconductor structures. After that it is described the theory of calculation of the diffusion length of minority carriers in semiconductors of type N and P. The aim of the experiment part of the thesis is to measure the properties of the semiconductor structure by EBIC and determination of diffusion length and lifetime of minority charge carriers based on the measured data The aim of the experiment part of the thesis is to measure the properties of the semiconductor structure by EBIC and determination of diffusion length and lifetime of minority charge carriers on the basis of the measured data.
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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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Semiconductors structures , charge collection method
Golda, Martin ; Čudek, Pavel (referee) ; Špinka, Jiří (advisor)
This thesis treats about semiconducting silicon structures. It describes the characteristics of the element and creation of P and N type of semiconductor and discusses about different types of faults in the crystal lattice. It deals with the description of methods for monitoring faults in semiconductor ie. determining the properties of semiconductors via EBIC, EBIV and CC methods, which are used for analysis of semiconductor devices and materials. Determining the properties of silicon components is being done by generation of charge carriers in the sample loaded in chamber of the scanning electron microscope by high energy electrons. Bellow the sample surface is being generated an electric charge which is being collected by probes. Using this data obtained by EBIC and CC were evaluated diffusion length and lifetime of electrons.
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Design of a photovoltaic power system with battery storage for household purposes in area of Brno-mesto
Vrana, Martin ; Vanýsek, Petr (referee) ; Vaněk, Jiří (advisor)
Táto bakalárska práca sa zameriava na rešerš technológií obsiahnutých v návrhu fotovoltického systému, ako sú solárne panely, nabíjateľné akumulátory, a systémy na premenu elektrickej energie. Následne sú tieto informácie využité na návrh hybridného a sieťového fotovoltického systému pre rodinný dom nachádzajúci sa v lokalite Brno-Mesto. Plán realizácie je nájsť cenovo výhodné riešenie s rozumným časom návratnosti, ktoré prevažne pokryje energetický odber domácnosti. Takisto sú náklady každého zo systémov znížene o dostupné štátne dotácie podľa parametrov každej inštalácie. Sieťový systém je lacnejší ako hybridný systém, pretože systém neobsahuje drahé batérie. Preto má nižšiu dobu návratnosti šiestich rokov, v porovnaní so siedmimi rokmi v prípade hybridného systému. Hybridný systém je výhodný, pretože umožňuje lokálne ukladanie energie a poskytuje záložné napájanie v prípade výpadku prúdu. Dodávateľ elektriny umožňuje uložiť prebytočnú energiu vyrobenú systémami do virtuálnej batérie, z ktorej je možné počas roka čerpať v čase nedostatočnej výroby energie. V kombinácii so súčasnými vysokými cenami energie majú oba systémy relatívne krátke obdobie finančného bodu zvratu v porovnaní so systémami v minulosti. Finálny výber typu inštalovaného systému je na klientovi.
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Noise diagnostics of rectifier diodes PN junctions
Klimíček, Jaromír ; Macků, Robert (referee) ; Raška, Michal (advisor)
The thesis deals with the design of the measurement installation, which is intended for the microplasma noise measurements. This noise is being generated in the defective parts of the PN junction. The goal of this work is to design the measurement installation and to realize the fully functional workbench for the analogical noise related measurements and to determine the transfer function of the measurement installation. Main part of the work is to choose proper parameters for the measuring devices and to design the software intended for the automated measurements. Consequently, we have to process the measured waveforms of the microplasma noise, to determine the dependency of the noise on the signal magnitude and to calculate the power spectral noise density. Finally, we have to determine the transfer function of the measurement installation and to design the inversion filter.
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Microplasma Noise as a Diagnostic Tool for PN Junctions of High-Voltage Rectifier Diodes
Raška, Michal ; Chobola, Zdeněk (referee) ; Hájek, Karel (referee) ; Koktavý, Pavel (advisor)
The doctoral thesis deals with diagnostics of local defects in PN junctions and brings new information about microplasma noise behaviour and its usage for the temperature changes detection inside PN junctions. Defects in PN junctions are the source of microplasma noise. There were deviations observed in microplasma noise from the common known rectangle shape pulses during the measurements. These deviations were correlated with the temperature change directly in the defect area and in the defect area surroundings. Generation and recombination coefficients are commonly thought to be constant. However, these coefficients were observed to be not stable with time and this effect is explained in this work. The doctoral thesis then focuses on the PN junction parameters determination in the case when it is not possible to define unambiguously whether it is abrupt or linearly graded PN junction. The most significant parameters which are to be determined are barrier capacity, diffusion voltage and depleted area width in dependence on the voltage. The correlation between local avalanche discharge in PN junction and negative differential resistance appearance on VA characteristics of reverse-biased diode was qualitatively verified. The last important point in the work is computer modelling of temperature behaviour in the defect area and its surroundings during local avalanche breakdown. Thus the method of real diodes heating area parameters determination was introduced.
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Application of radiation emitted from local areas of PN junction for solar cell diagnostics
Krčál, Ondřej ; Raška, Michal (referee) ; Macků, Robert (advisor)
The microplasma discharges in the PN junction local defect micro-regions are as a rule, accompanied by the emission of light. This radiation from solar cell PN junctions was measured by means of a optical fibre connected to the optical input of a photomultiplier. By inching the fibre by means of computercontrolled X-Y plotter above the cell surface a 2-D image of the irradiation local regions has been created. It is seen that a cell of a superficial area of 100 square cm contains a large number of defects, which depends on applied reverse voltage. This method can be a convenient tool for study and diagnostics of optoelectronic devices.
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Design of VA-characteristic meter
Štěpnička, Martin ; Szabó, Zoltán (referee) ; Steinbauer, Miloslav (advisor)
The thesis describes the design of a measuring device volt-ampere characteristics of PN junction suitable for measuring characteristics of stabilizing diodes. Describes the basic principle of PN junction and related events. Part of the text discusses how to minimize the adverse parasitic effects. Furthermore, the proposal deals with an AC adapter suitable for this device. With that analyzes marginally rectifiers, stabilizers and filters. The following is a description of the device for measurement, principle of communication with the computer and the method of data processing. The annex contains schematic design, printed circuit boards and part list.
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Operating Characteristics of LED Sources
Brdečko, Aleš ; Diviš, Daniel (referee) ; Baxant, Petr (advisor)
This semester thesis is dealing with issues of LED (light emiting diod).In the text we can find general summary knowledges about LED, relating their history, construction, principle of working and also treatise about of semiconductor compounds. In thesis are given examples of use indicating their advantages and disadvantages and indicating their parameters. The practical content of this thesis is evaluation of measurement performed on some samples of LED especially graphics addiction of crosses and V-A characteristics measured in addiction on current.
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