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Semiconductor properties
Řihák, Pavel ; Frk, Martin (referee) ; Špinka, Jiří (advisor)
This bachelor's project deals with methodology for determination the semiconductors parameters. Particularly, it deals with methods of diffusion length measurrement. Various methods of measurement were studied for this purpose and selected the most suitable one. Which was carried measurements on a sample of silicon using IR power LEDs.
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Semiconductor diode modelling
Pacholík, Vladimír ; Wilfert, Otakar (referee) ; Pokorný, Michal (advisor)
This project is about phenomena, which proceed in semiconductor, eventually on semiconductor junction, including equations and relatives necessary for modeling simply semiconductor PN diode, Gunn diode and Schottky diode. Further including short way, how to use this equations and how simulate this diode in COMSOL Multiphysics and Tiber CAD software. Products of modeling are data in charts form. This charts giving basic idea about charge carriers, electrostatic potential and I-V characteristic.
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Diagnostics of semiconductors properties
Šeliga, Ladislav ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This thesis describes the basic properties of semiconductor materials and methods of their measuring. In the first part of this work are discussed elemental semiconductors, semiconductor compounds and the band structure. The next section describes current conduction in semiconductors, methods for measuring resistivity. This work is focused on the measuring drift mobility of minority charge carriers using the Haynes-Shockley method for a sample of silicon semiconductor, the creation of automated workplace in the development environment VEE Pro and resistivity measurements of silicon samples.
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Study of optoelectrical properties of organic semiconductor thin film layers
Kovář, Jakub ; Weiter, Martin (referee) ; Zmeškal, Oldřich (advisor)
This thesis concerns with electrical and optoelectical properties of thin organic semiconductor layers. In the research, organic electroluminescent devices were prepared and the effect of illumination and inclusion of organic interlayers, that act as alternative electrodes, on charge injection and transport were investigated on them by means of electrical measurement and impedance spectroscopy. On the basis of measured data, the thesis attempts to determine materials best suited for interlayers, which could make an improvement of electric properties of electroluminescent devices possible. The sence of using a combination of direct current measurement and impedance spectroscopy was also discussed in the thesis.
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The temperature measurement with semiconductor sensor
Dostálek, Martin ; Klíma, Bohumil (referee) ; Huták, Petr (advisor)
This bachelor work disserts on measurement of temperature using the electronic temperature sensors DS18B20, which are controlled by microcomputer type AVR. This sensors use for communication the 1-wire type data bus. The 1-wire data bus, designed by Dallas Semicondoctor, allows connect more devices to the control unit using two wires. This type of measuring elements offers simple handling for the user. The sensor transforms the measuring data directly to the digital data. The rate of the transmission is determined by number of bits in the resultant value and the sensor is programmable during attendance by the set mechanism (master). The sensor code is consistent with the value of measured temperature. That means it doesn’t require supplemental decoding. The resulting data are worked up and displayed on LCD continuously. First part of this work is focused on the theory of 1-wire element. Further, there is an explanation of the principle of the measuring sensor function and its controlling by the control unit. Next, there is a basic description of the AVR type microcomputers, more detailed description is aimed at the ATiny2313 controller, which is used in this work. The important part is dedicated to the implementation of the 1-wire protocol to the appropriate control unit.
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Optimalization of gel electrolyte for printed UV sensor based on photoelectrochemical cell
Vrbková, Kateřina ; Gemeiner,, Pavol (referee) ; Dzik, Petr (advisor)
This paper deals with the construction of photoelectrochemical cell, used for detection of ultraviolet radiation as a UV sensor. Photoelectrochemical cell consists of three layers, layer of photoactive semiconductor titanium dioxide, carbon electrodes and poly(vinyl alcohol) polymer electrolyte. The sensor layer enables the detection of UV radiation with the subsequent generation of photocurrent. Material printing techniques, such as screenprinting, pad printing and inkjet printing were used to produce the cell. Gel electrolyte was characterized by optical microscopy and rheometry. Sensor functionality was verified by use of electroanalytical techniques.
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Photocell as a power source for a small DC motor of RC car model
Nábělek, Ondřej ; Huzlík, Rostislav (referee) ; Mikulčík, Aleš (advisor)
The goal of this project is to acquaint the reader with problems of solar cells and project of systems for solar cells power a small electric machine performance. Preliminary discussion of the energy produced by the Sun incident on the Earth. Another chapter contains information about the fundamental function of solar silicon cells and conversion of solar energy to electric energy. Main part of this work is devoted to various types of solar cells, production materials, the structure of cells and solar panel. The last part is a measurement system for solar cells, the verification of theoretical assumptions and evaluate the results of the work.
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Tensometric measuring
Trojan, Vítězslav ; Kandus, Bohumil (referee) ; Podaný, Kamil (advisor)
This work is engaged in tensometric measuring. This work reports basic principles of tensometric measuring and problems connected with measurements. Different types of tensometres and their applications are described and elemental exercisee for common kinds of strain is infered. Suitability of tensometric sensor usage in mechanical engineering is discussed.
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Operating parameters of LED light sources
Janík, Daniel ; Mikulka, Jan (referee) ; Havlíková, Marie (advisor)
The aim of the thesis is to introduce the basic photometric quantities and operating parameters of LED light sources, according to which the light sources are evaluated and compared. The thesis examines effects of high temperature and elevated stress on LED retrofits and a design of measurement methods to measure these influences. According to the proposed methods, nine samples of light sources were measured and compared to each other on a basis of the measurements. Comparison was made from the point of view of the energy as well as the quality of the produced light. The results were also compared to the parameters specified by the producers.
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Fundamental properties of semicomductor materilas
Kahánek, Tomáš ; Jirák, Josef (referee) ; Špinka, Jiří (advisor)
This work deals with fundamental properties of semiconductors materials and methods of their measuring. This work is focused on non-contact methods using light to generate electric charge in semiconductor. Tests were focused on measuring characteristics of PN transition light diods and semiconductor specimen with big resistivity, there was founded absorption edge of silicon.
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