National Repository of Grey Literature 197 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Application of correlative AFM/SEM microscopy
Hegrová, Veronika ; Fejfar, Antonín (referee) ; Konečný, Martin (advisor)
This thesis is dealing with application of Correlative Probe and Electron Microscopy. All measurements were carried out by atomic force microscope LiteScope which is designed especially to be combined with electron microscopes. Advantages of Correlative AFM/SEM Microscopy are demonstrated on selected samples from field of nanotechnology and material science. Application of the correlative imaging was proposed and then realized particularly in case of low-dimensional structures and thin films. Further, this thesis deals with the possibility of combining Correlative AFM/SEM Microscopy with other integrated techniques of an electron microscope such as Focused Ion Beam and Energy Dispersive X-rays Spectroscopy.
Metallization of technical plastics for lightweight traffic components with reduced fuel consumption
Sanetrníková, Dominika ; Boušek, Jaroslav (referee) ; Šimůnková, Helena (advisor)
The beginning of this thesis is dedicated to polymeric materials, which include plastics an composites. Plastics are shortly divided into two groups, thermoplastics and thermosets. The following part is the use of plastics and composites in traffic industry and briefly this work focuses on techniques of recycling of this materials. This work also focuses on the techniques of thin film deposition, electroless plating, electrodeposition as well and plating in the vacuum environment. special techniques of thin film deposition are also mentioned shortly. The coatings of polymer including cleaning and surface activation is introduced using various techniques including plasma treatment. The surface treatment of polyetheretherketone (PEEK) is included too. The final part describes performed experiments and discussion of results.
Plasmachemical deposition and characterization of hexamethyldiloxane thin layers
Blahová, Lucie ; doc. Mgr. Vít Kudrle. Ph.D. (referee) ; Krčma, František (advisor)
Thin films have been used to modify surface properties of various materials for many years. Plasma Enhanced Chemical Vapor Deposition (PECVD) is one of the possible methods for their preparation and this technique is applied in this work as well. An organosilicone – hexamethyldisiloxane – is used as precursor. Thin films are created on the surface of the substrate using mixture of precursor and oxygen in radiofrequently excited capacitively coupled plasma. The aim of the thesis is to find the optimal deposition conditions for production of transparent thin layers with good barrier capabilities, low oxygen transmission rate especially. Thin film depositions were realized for different compositions of the deposition mixture in continuous and pulsed mode of plasma with varying supplied power and duty cycle values. The deposition process itself was monitored in situ by optical emission spectroscopy. Thin film coatings were analyzed to determine their physical chemical properties (infrared spectroscopy, surface energy) and barrier properties. Using optical emission spectroscopy, important particles were identified in the deposition plasma. Vibrational, rotational and electron temperatures were determined from relative intensities of chosen fragments. Composition of thin films was studied by infrared spectroscopy. The best results of oxygen transmission rate were achieved with layers prepared from deposition mixture with high oxygen content. It was possible to improve barrier properties by performing deposition in pulsed plasma mode with 20–30% duty cycle. In this diploma thesis, optimal deposition conditions of thin films from hexamethyldisiloxane with low oxygen transmission rate were determined. It is possible to use these results in practical applications, such as corrosion inhibitors for archaeological objects. Optionally, they can be used in various industry branches where it is desirable and feasible to prevent oxygen access to the material by deposition of barrier coatings.
Comparison of properties of thin layers of titanium, nickel and silver used in semiconductor technology
Dorotík, David ; Prášek, Jan (referee) ; Hejátková, Edita (advisor)
Bachelor theses were connected with knowledge of general problems of application of thin films by methods of sputtering and evaporation. Prepare the substrate and clean it before depositing thin layers. The work was focused on the properties of these thin films in semiconductor technology.
Káňa, Tomáš ; Vřešťál, Jan (referee) ; Paidar,, Václav (referee) ; Černý, Miroslav (referee) ; Šob, Mojmír (advisor)
This work presents a theoretical study of stability of phases in selected metallic systems. We propose a model of structural transformations in transition metal disilicides MoSi2, CrSi2, VSi2 and TiSi2 and in Pd thin films grown on cubic substrates W(001) and Nb(001). The obtained results yield the total energy proles for the structural transformations studied, the activation energies needed for each individual transformation and an estimate of the temperature at which the structure can transform. The total energies are calculated by full-potential linearized augmented plane waves (FLAPW) method incorporated in the WIEN2k code. Both generalized gradient approximation (GGA) and local density approximation (LDA) are employed for the exchange-correlation term. It turns out that temperatures corresponding to the activation energies of structural transformations in transition metal disilicides exceed their melting temperatures. Comparing the resulting total energy proles to those obtained by the semiempirical Bond Order interatomic potentials (BOP) substantially helps to adjust the fitting parameters of the BOPs. The estimated temperature of 168 K needed to transform the hcp structure of an innite Pd crystal into the dhcp structure explains the behavior of the Pd thin lm on W(001) and Nb(001) substrates. Pd lms deposited on W(001) substrate and thicker than about 100 monolayers undergo this transformation already at room temperature. Thinner lms need to be annealed at 400 K rst, due to their stronger interaction with the substrate. The difference between the computed result and a real temperature at which the hcp Pd lm transforms its structure to the dhcp can be explained by both the interaction between the lm and the substrate and by the inuence of the domain topology of the lm. Analyzing different models of transformation of the initial hcp Pd structure to the ground state fcc structure, we identied the optimum model that respects the domain topology of the Pd lm.
Design and set up of a laboratory sample of a laser deflectometer for measurement of mechanical stress within thin films
Šustek, Štěpán ; Klapetek,, Petr (referee) ; Ohlídal, Miloslav (advisor)
This diploma thesis describes the design of a device for measuring stress in thin films – laser deflectometer, realization of its design and its experimental testing. The thesis is divided into five chapters. The first chapter deals with the stress in thin films and its influence on substrate – thin film system. The second chapter provides an overview of devices widely used for measuring stress in thin films and describes some their advantages and disadvantages. In the third chapter some design possibilities of the device are presented. The final solution of device called deflectometr is introduced in the fourth chapter. The last chapter includes the functional testing the device.
Study of plasma species by mass spectroscopy
Bureš, Michal ; Čáslavský, Josef (referee) ; Čech, Vladimír (advisor)
Plasma polymer films of tetravinylsilane and mixture of tetravinylsilane and oxygen gas were deposited on silicon wafers. Oxygen gas was mixed in tetravinylsilane to improve the compatibility of thin films on glass substrates. Mass spectroscopy was employed during the cleaning of the deposition chamber to check residual gases and process gases, during plasma deposition to monitor neutral plasma species and to follow plasma stability.
Optimization of thin films of metal oxide materials
Vítek, Jiří ; Šimonová, Lucie (referee) ; Šubarda, Jiří (advisor)
This thesis is focused on the description of the method of reactive sputtering of thin films. Currently, there are many ways how to create thin films and there are many applications of thin films in various industrial sectors. In this paper at the first are listed the issue of thin films, followed by an overview of the deposition techniques and of the chemical analysis of deposited thin films. It also describes the four-point measurement method of sheet resistance, mechanical test of adhesion and optical properties. At the end of the theoretical part are described the material composition of the deposited films. The goal of the practical part is to optimize the deposition process of the mixed layer of indium tin oxide (In2O3: SnO2) and contribute to the overall understanding of the influence of annealing on the layer. There were created six series of samples with that applied layers. First, the work focused on examining of the influence of annealing on the throughput in the whole measuring range, and then comparing the series due to the transmittance in the visible light spectrum. Furthermore were compared the value of sheet resistance of unannealed and subsequently annealed samples.
Ellipsometry of Thin Films
Novotný, Zbyněk ; Navrátil, Karel (referee) ; Nebojsa, Alois (advisor)
Diploma thesis deals with ageing process of thin films of Co and Cu on Si substrate, prepared by the IBAD method. The process of film ageing, which depends on time of exposition to the atmosphere at room conditions, was investigated with spectroscopic ellipsometry (VIS+UV) and atomic force microscopy. In case of thin Co films, approximately four days long incubation period was observed. During this time period, a change in the optical parameters of the film occurs without a measurable change of the film topography. Using non-contact atomic force microscopy, a growth of the transitional film in the island growth regime was observed. During the ageing of thin Cu films, two stages of growth of the transitional layer were observed - nucleation stage and growth stage. Both of these time periods of the transitional layer growth show direct logarithmic dependence. Using non-contact atomic force microscopy, the growth of the transitional film was observed. Using atomic force microscopy in non-contact regime, time dependent measurement was done and the process of forming of one monolayer of the transitional layer was documented. Within the diploma thesis, a series of experiments on ultra high vacuum system were performed in order to investigate phase transformation of thin Fe films (22 monolayers) on Cu(100) stabilized by CO absorption. The transformation from fcc phase to bcc phase was induced by Ar+ ion beam bombardment with the ion energy in the range (0.5-4) keV. The process of phase transformation was observed by surface magneto-optic Kerr effect, Auger electron spectroscopy and low energy electron diffraction.
Analysis of a-SiOC:H films by selected spectroscopic techniques
Ondreáš, František ; Zmeškal, Oldřich (referee) ; Čech, Vladimír (advisor)
This bachelor thesis deals with preparation of thin plasma polymer films on the basis of tetravinylsilane by plasma-enhanced chemical vapour deposition and film characterization by selected spectroscopic techniques. The theoretical part is a background research about plasma chemistry and spectroscopic methods of characterisation of thin plasma polymer films. The practical part consisted of preparation of two series of samples and their characterization. Prepared thin plasma polymer films were characterized by selected spectroscopic techniques. Thickness and optical constants were determined by spectroscopic elipsometry. Chemical structure was characterized by infrared spectroscopy. The results indicate the possibility of managing physico-chemical properties of thin plasma polymer films on the basis of tetravinylsilane by deposition conditions and thus possibility of preparation materials tailored to a variety of applications.

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