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Characterisation of dielectric films on a silicon wafer
Fillner, Patrik ; Boušek, Jaroslav (referee) ; Hubálek, Jaromír (advisor)
This bachelor thesis focuses on thin oxide based dielectric layers on silicon wafer. Main effort is for characterization of properties of samples. This technology can be used for manufacturing capacitors on silicon chips. Samples are based on planar oxide layers made with thin film technology on single silicon wafers coated with electrodes deposited by evaporation or by sputtering.
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Study of the influence of the dielectrics on the optoelectronic properties of electroluminescent devices
Foldynová, Klára ; Novák, Vítězslav (referee) ; Vala, Martin (advisor)
This diploma thesis is studing the possibilities of influencing the optoelectric properties of printed light emitting panels, which work on the principle of electroluminescence excited by alternating electric field. The aim of this worrk is to monitor the influence od dielectric properties of electroluminescent phosphor binder on the targeted electroluminescence. In the theoretical part of this thesis, there are described principles of electroluminescence, suitable materials methods of characterization and preparation of panels using printing techniques. Experiment part contains electrical characterization of selected binders to determine their dielectric constants. Subsequently, printing pastes were formulated in different weight ratios of binder electroluminescent phosphor and model light-emitting panels were prepared. Optoelectric characterization was used to determine the change in irradiance. It was found that the dielectric properties of the binder significantly affect the resulting irradinace. It has same irradiance for a smaller amount od phosphor than with the binder with a low dielectric constant. The finding of this work can be used to improve the luminosity at the electroluminescent panels.
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Time-domain Dielectric Spectroscopy of Carboxymethylcellulose
Palai-Dany, Tomáš ; Lelák, Jaroslav (referee) ; Mentlík, Václav (referee) ; Liedermann, Karel (advisor)
The dissertation deals with the time-domain dielectric relaxation spectroscopy of carboxymethylcellulose. The main attention was paid to the experimental part of research, mainly to the design and subsequent development of an experimental setup for the measurement of discharge currents and for their processing and analysis. The subject of the measurement is carboxymethylcellulose (CMC), which is a simple polysaccharide used in wide range of applications, among else also in biomedical engineering. The study of CMC properties has required the development of a new experimental set-up of original design, which includes the equilibration (short-circuiting) of a sample before the measurement, charging and discharging at defined time intervals, switching between these two modes, recording of measurement, adjustments and processing of measured signals up to Fourier transformation into the frequency domain and, finally, calculation of complex permittivity of the sample. The frequency dependence of complex permittivity or its imaginary part, obtained by Fourier transformation of discharge current in time domain, is then referred to as the dielectric spectrum. In view of the fact that current measurements were done at very low levels of measured signal (below 10-12 A) the whole measurement was no easy matter. The framework of the work also necessitated studies and subsequent resolution of problems associated with shielding, grounding, presence of noise and sensitivity to various ambient influences. The research work focused on a reliable and trustworthy measurement of very low discharge currents and, subsequently, mathematical processing of noise present in them, i.e., operations with the original, experimentally established signal in time domain, leading in principle to a digital filtration of measured dielectric data. A further pursued objective is the explanation of dielectric parameters of tested carboxymethylcellulose sample in the widest possible frequency spectrum. The integral part of the research was the selection and application of the method for the transformation of the adjusted signal to the frequency domain. The experimental works, including data processing, were carried out in the Department of Physics, Brno FEEC BUT. Measurements were done with Keithley 617 Electrometer, HP4284A Frequency Analyzer and Janis CCS-400-204 cryogenic system. The results were completed with results obtained at the V Department of Experimental Physics, Centre for Electronic Correlations and Magnetism, University of Augsburg, Germany.
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Study of the influence of the dielectrics on the optoelectronic properties of electroluminescent devices
Foldynová, Klára ; Novák, Vítězslav (referee) ; Vala, Martin (advisor)
This diploma thesis is studing the possibilities of influencing the optoelectric properties of printed light emitting panels, which work on the principle of electroluminescence excited by alternating electric field. The aim of this worrk is to monitor the influence od dielectric properties of electroluminescent phosphor binder on the targeted electroluminescence. In the theoretical part of this thesis, there are described principles of electroluminescence, suitable materials methods of characterization and preparation of panels using printing techniques. Experiment part contains electrical characterization of selected binders to determine their dielectric constants. Subsequently, printing pastes were formulated in different weight ratios of binder electroluminescent phosphor and model light-emitting panels were prepared. Optoelectric characterization was used to determine the change in irradiance. It was found that the dielectric properties of the binder significantly affect the resulting irradinace. It has same irradiance for a smaller amount od phosphor than with the binder with a low dielectric constant. The finding of this work can be used to improve the luminosity at the electroluminescent panels.
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Characterisation of dielectric films on a silicon wafer
Fillner, Patrik ; Boušek, Jaroslav (referee) ; Hubálek, Jaromír (advisor)
This bachelor thesis focuses on thin oxide based dielectric layers on silicon wafer. Main effort is for characterization of properties of samples. This technology can be used for manufacturing capacitors on silicon chips. Samples are based on planar oxide layers made with thin film technology on single silicon wafers coated with electrodes deposited by evaporation or by sputtering.
|
|
|
Time-domain Dielectric Spectroscopy of Carboxymethylcellulose
Palai-Dany, Tomáš ; Lelák, Jaroslav (referee) ; Mentlík, Václav (referee) ; Liedermann, Karel (advisor)
The dissertation deals with the time-domain dielectric relaxation spectroscopy of carboxymethylcellulose. The main attention was paid to the experimental part of research, mainly to the design and subsequent development of an experimental setup for the measurement of discharge currents and for their processing and analysis. The subject of the measurement is carboxymethylcellulose (CMC), which is a simple polysaccharide used in wide range of applications, among else also in biomedical engineering. The study of CMC properties has required the development of a new experimental set-up of original design, which includes the equilibration (short-circuiting) of a sample before the measurement, charging and discharging at defined time intervals, switching between these two modes, recording of measurement, adjustments and processing of measured signals up to Fourier transformation into the frequency domain and, finally, calculation of complex permittivity of the sample. The frequency dependence of complex permittivity or its imaginary part, obtained by Fourier transformation of discharge current in time domain, is then referred to as the dielectric spectrum. In view of the fact that current measurements were done at very low levels of measured signal (below 10-12 A) the whole measurement was no easy matter. The framework of the work also necessitated studies and subsequent resolution of problems associated with shielding, grounding, presence of noise and sensitivity to various ambient influences. The research work focused on a reliable and trustworthy measurement of very low discharge currents and, subsequently, mathematical processing of noise present in them, i.e., operations with the original, experimentally established signal in time domain, leading in principle to a digital filtration of measured dielectric data. A further pursued objective is the explanation of dielectric parameters of tested carboxymethylcellulose sample in the widest possible frequency spectrum. The integral part of the research was the selection and application of the method for the transformation of the adjusted signal to the frequency domain. The experimental works, including data processing, were carried out in the Department of Physics, Brno FEEC BUT. Measurements were done with Keithley 617 Electrometer, HP4284A Frequency Analyzer and Janis CCS-400-204 cryogenic system. The results were completed with results obtained at the V Department of Experimental Physics, Centre for Electronic Correlations and Magnetism, University of Augsburg, Germany.
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