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The photoluminescence properties measurement of ultrathin films
Metelka, Ondřej ; Mach, Jindřich (referee) ; Šamořil, Tomáš (advisor)
The thesis briefly describes the principles and types of luminescence. In the first following research of study is also discussed the equipment which is applicable to photoluminescence experiments, including the arrangement. The second research focuses on the influence of the properties of gallium nitride (GaN) (ultra) thin films and other structures prepared by various ways on shape of photoluminescence spectra. The paperwork also describes the further optimization of photoluminescent apparatus used for the measurement of photoluminescence spectrum in the UV light radiation which is located at the Institute of Physical Engineering at the Technical University. The extension of measurements at low temperatures (design and construction of its own cryostat) is added. The conclusion concernes the test measurements to determine the effect of various settings of the apparatus on the resulting measured photoluminescence spectrum.
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Calibration of SIMS method by implantation profiles
Janák, Marcel ; Průša, Stanislav (referee) ; Bábor, Petr (advisor)
This bachelor thesis is concerned with a quantitative analysis of the dopant (C, H, Mg, O) distribution in MOCVD-grown AlGaN HEMTs by TOF.SIMS 5 instrument with cesium and oxygen sputtering. The main reason for the development of RSF SIMS measurement quantification method is a hardly predictable phenomenon of preferential sputtering and matrix effect. Calibration samples, prepared by ion implantation technique into homogeneous and periodic III-nitride AlN, GaN structures, are reproduced by an ion-atom interaction program TRIM. A part of this work is likewise a quantification of AlGaN matrix.
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Calibration of SIMS method by implantation profiles
Janák, Marcel ; Průša, Stanislav (referee) ; Bábor, Petr (advisor)
This bachelor thesis is concerned with a quantitative analysis of the dopant (C, H, Mg, O) distribution in MOCVD-grown AlGaN HEMTs by TOF.SIMS 5 instrument with cesium and oxygen sputtering. The main reason for the development of RSF SIMS measurement quantification method is a hardly predictable phenomenon of preferential sputtering and matrix effect. Calibration samples, prepared by ion implantation technique into homogeneous and periodic III-nitride AlN, GaN structures, are reproduced by an ion-atom interaction program TRIM. A part of this work is likewise a quantification of AlGaN matrix.
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The photoluminescence properties measurement of ultrathin films
Metelka, Ondřej ; Mach, Jindřich (referee) ; Šamořil, Tomáš (advisor)
The thesis briefly describes the principles and types of luminescence. In the first following research of study is also discussed the equipment which is applicable to photoluminescence experiments, including the arrangement. The second research focuses on the influence of the properties of gallium nitride (GaN) (ultra) thin films and other structures prepared by various ways on shape of photoluminescence spectra. The paperwork also describes the further optimization of photoluminescent apparatus used for the measurement of photoluminescence spectrum in the UV light radiation which is located at the Institute of Physical Engineering at the Technical University. The extension of measurements at low temperatures (design and construction of its own cryostat) is added. The conclusion concernes the test measurements to determine the effect of various settings of the apparatus on the resulting measured photoluminescence spectrum.
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A Comparison of Titania Nanoparticles Production in Two Different Reactors by MOCVD Method
Moravec, Pavel ; Smolík, Jiří ; Schwarz, Jaroslav ; Vodička, Petr ; Levdansky, V.V. ; Koštejn, Martin
Nanoparticles (NP's) have attracted considerable attention, because they show a quantum size effect, for which the physical and chemical properties are strongly dependent on particle size. This change of properties can also affect the toxicity and therefore NP's cannot be treated the same way as bulk material. In spite of that, inhalation studies of NP's are still rather rare. Recently, an exposure system for inhalation experiments was constructed in the Institute of Analytical Chemistry AS CR and the first experience with this system were reported by Večeřa et al., 2012. For these studies, a method of continual long-term generation of NP's in the gas phase is necessary. Methods for long-term generation of MnOx and Pb/PbOx NP's have recently been reported. The next task was to test the method for long-term generation of TiO2 NP's suitable for subsequent inhalation experiments.
Fulltext: content.csg -  PDF
Plný tet: SKMBT_C22014102013554 - PDF
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Synthesis of Lead and Lead Oxide Nanoparticles for Inhalation Experiments
Moravec, Pavel ; Smolík, Jiří ; Ondráček, Jakub ; Vodička, Petr ; Fajgar, Radek
From the three tested methods of NP's generation the evaporation/condensation of metallic Pb seems to be the most suitable for long lasting inhalation experiments due to its simplicity, unambiguous mechanism of NP′s formation and well defined composition. Nevertheless, NP′s can change their composition, at least on the surface layer, during the time-lag between their formation and inhalation. Thermal decomposition of PbTHD2 can produce sufficiently high concentration of NP′s but there is some uncertainty about their composition due to presence of OC in NP′s. Oxidation of PbTHD2 produces carbon free NP′s, but the number concentration of NP′s is somewhat low.
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22013101814595 - PDF
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Generation of Pb/PbOx Nanoparticles for Inhalation Experiments
Moravec, Pavel ; Smolík, Jiří ; Ondráček, Jakub ; Vodička, Petr ; Fajgar, Radek
Health aspects of nanoparticles (NP′s) on living beings are considered to be important. However, the real data of the impact of NP′s inhalation are rather rare. A study of allocation of MnOx nanoparticles in organs of laboratory animals in inhalation chamber was presented by Večeřa and Mikuška (2012). For these experiments a source of continual generation of nanoparticles in duration of days or even weeks and in appropriate concentration is necessary. In this work a study of continual generation of Pb/PbOx nanoparticles in hot wall tube reactor are presented.
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22013091912130 - PDF
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ZnO NANOPARTICLES AND THEIR APPLICATIONS – NEW ACHIEVMENTS
Nohavica, Dušan ; Gladkov, Petar
The advantages of ZnO are a low price, good gas sensing properties, photocatalytic activity, antibacterial activity, possibility to prepare structures with interesting optical properties, like photonic crystals, catalytic materials etc. In our laboratory the special research type of MOCVD apparatus has been developed. In the study we have investigated the influence of the growth rate on the morphology of ZnO deposited on Si (100), GaP (111) as well as nanoporous GaP. The same apparatus has been used for ZnO nanoparticles preparation with the diameter of individual nanoparticles of about 25 nm.
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