National Repository of Grey Literature 8 records found  Search took 0.01 seconds. 
Temperature changes in thin films of nanoparticles
Krtouš, Zdeněk ; Kousal, Jaroslav (advisor) ; Hanuš, Jan (referee)
Many properties of nanoparticles are different from general bulk properties. This work is focused on coalescence of nanoparticles depending on temperature.Coalsescence was experimentaly measuered on gold nanoparticles, copper nanoparticles and silver nano- islands.The samples were characterised by SEM, AFM and in-situ ellipsometry in range between 20řC and 350 řC. In the theoretical part was analyzed existing semi-analytical model of coalescence and then it was created a new model based on previous one. In the end, the comparison between experimental data and model was done. New model predicts greater coalescence of nanoparticles, what corresponds to experimental data.
Deposition of ultrathin films on polymers
Libenská, Hana ; Hanuš, Jan (advisor) ; Kousal, Jaroslav (referee)
Thin metal films deposited on the polymer substrates are of fundamental importance for the formation of conductive structures on the surfaces of the polymers. In the case of discontinuous layers of silver or copper, so-called anomalous absorption occurs in the visible range of the spectrum. This phenomenon can be used to create different sensors, eg. based on surface enhanced Raman spectroscopy. In this work, the deposition of discontinuous Ag and Cu layers on PEEK and PET polymer foils and glass and polished silicon was used studied. The magnetron sputtering was chosen for deposition at very low pressure and the effect of pressure on the growth of these films was investigated. It was found that at a pressure of 0.2 Pa the copper layers on the two polymers grew almost smooth, while the island structure appeared at a pressure 1.2 Pa. In the case of Ag deposition, the island structure of the layer appeared already at a pressure of 0.2 Pa, and differences in the growth of the Ag films in dependence of the the substrate were observed.
Study of the interaction of nanocomposite films with plasma
Steinhartová, Tereza ; Hanuš, Jan (advisor) ; Kousal, Jaroslav (referee)
The theoretical part deals with basic characteristics of low-temperature, low-pressure plasma. It describes the principles of preparation of nanocomposite films using this type of plasma and also the etching process in chemically active plasma. It further explains the basic principles of methods used to characterize our samples. The experimental part describes the process of optimalization of chemically active plasma ($O_2/Ar$) employed for etching of plasma polymer films. After finding suitable etching parameters several types of films were prepared. First, films of plasma polymer and then nanocomposite films composed of metal and plasma polymer. Afterwards the samples were treated in defined conditions of oxygen plasma. The aim was to study the physico-chemical properties of these films, especially their chemical composition using X-ray photoelectron spectroscopy, and wettability. Attention was given to the change of the water contact angle as a function of etching time and morphology of the pample. In case of oxygen etching ageing of the film was studied. By increasing of roughness superhydrophobic (SHF) film was prepared.
Fabrication of metal nanoclusters and their characterization
Kratochvíl, Jiří ; Kylián, Ondřej (advisor) ; Kousal, Jaroslav (referee)
Copper nanoclusters have potencial for fabrication of nanostructured surfaces, which can be used in electronics, electrotechnics, optics and in biomedical applications. To create such surfaces, it is necessary to create and characterize the nanoclusters deeply first and this is the main topic of this work. First, we found repeatable procedure to create copper nanoclusters by the gas aggregation nanocluster source. We studied homogenity of prepared surfaces by quartz crystal microbalance and optical ellipsometry, we determined conditions for deposition of homogeneous coatings. Next, we studied deposition rate in dependence on the magnetron current, pressure in the aggregation and deposition chambers. Deposition rate linearly increased with current, but in low currents it was nearly zero. Furthermore, we found maximum deposition rate for a given pressure in the aggregation chamber and determined the range of pressure in deposition chamber where it is possible to deposit thin films of copper nanoclusters. This is important for fabrication of nanocomposite surfaces. We studied also the size, shape of nanoclusters and growth of surface by scanning electron microscope. The surfaces were very porous. We measured roughness and optical absorbance where anomalous optical absorption was found. Finally, we found that...
Diagnostics of plazma in the deposition sources using the Langmuir probes
Šedivý, Petr ; Kousal, Jaroslav (advisor) ; Kylián, Ondřej (referee)
This experimental work is concerned with measurement of elementary characteristics of plasma - potential of plasma, electron temperature and density of particles. As research methods were selected the Langmuir probes - especially the single probe. At the beginning of the thesis there are explained shortly the elementary characteristics of plasma and the procedure of determination particular parameters of the plasma from the volt-ampere characteristics of the probe. The third chapter is focused on description of the experiment, the probe, the apparatus and its control. Plasma measured within this work originated from the new hollow magnetron which will serve as future source of nanoparticles. Results of the work are focused on the description of individual parameters of the plasma in dependence on other variables such as the magnetron power, pressure of gas, spatial dependence or presence of additional auxiliary magnetic field.
Investigation of nanostructured films
Čechvala, Juraj ; Kousal, Jaroslav (advisor) ; Mistrík, Jan (referee)
In this thesis the optical properties of the plasma polymers are studied using the spectroscopic ellipsometry. The basic principles of ellipsometry are described. The suitability of various ellipsometric models for the modelling of plasma polymer thin filmsis compared. The stability of films prepared by sputtering of nylon is studied. The influence of the deposition conditions on the optical properties of hydrocarbon plasma polymer film is characterized. Usability of the ellipsometric roughness for the characterization of the nanostructured hydrophobic surfaces is tested. The filling factor of metal/plasma polymer nanocomposites is determined and compared with another methods of filling factor determination.

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2 Kousal, Jiří
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