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2D & 3D computer modelling of low-temperature plasma sheaths with a particular focus on their mutual interaction
Hromádka, Jakub ; Hrachová, Věra (advisor) ; Novotný, Dušan (referee) ; Kudrna, Pavel (referee)
The presented thesis deals with the study of the sheath layer which is formed during the interaction of a low-temperature plasma with a solid object using computer modelling techniques. The theoretical part of the thesis summarizes knowledge about the physics of the sheath layer of electropositive and electronegative plasma and presents the theory of measuring plasma parameters using a Langmuir probe, including a discussion of the effect of collisions of charged particles with neutrals on the probe measurements. Further, theoretical descriptions of the plasma are presented which are the basis of the computer models created in the framework of the thesis: a particle model based on the Particle-in-Cell method and a fluid model of the drift-diffusion approximation of the plasma. The developed particle model works in 3D space, uses the null-collision Monte Carlo method to account for the effects of collisions of charged particles with neutrals and implements the Intel Math Kernel Library functions to solve the Poisson's equation. The fluid model is implemented using FeniCS software. At first, the developed models are used for the calculation of the sheath layer and the current-voltage characteristics of free-standing Langmuir probes of several types: a 1D model of an infinitely large planar probe, a 2D model of...
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Computational study of initial stages of metal film growth
Soukup, Jindřich ; Hrach, Rudolf (advisor) ; Novotný, Dušan (referee)
This work deals with the description and analysis of image data, which related to the initial stages of the thin film growth. The introductory retrieval section includes a description of thin films and methods of their deposition. The following part is an overview of the growth models of thin layers. The heart of my thesis is the analysis and modification of morphological methods and interpretation of their results. The emphasis is placed on the statistical aspect of methods and their optimal implementation due to the accuracy of the results. The work shows how to modify the radial distribution function and methods based on so-called Voronoi and Delaunay triangulation tessellation so that they can better affect the character of test data. New methods are tested both on the experimental and model data. Then we examine their robustness, sensitivity and their mutual independence. At the conclusion it is introduced and analyzed a new model of thin film growth.
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Study of plasma-solid interaction at medium pressures
Roučka, Štěpán ; Hrach, Rudolf (advisor) ; Novotný, Dušan (referee)
The thesis is aimed at particle simulation of plasma at medium pressures. Main results concern modelling of collisions in particle-in-cell algorithm. Dierent methods of modelling of collisions are discussed and their accuracy and eciency are investigated. Furthermore a new modication of particle-in-cell algorithm for modelling at medium pressures was proposed. Numerical benchmarks in the nal chapter show advantages of the new algorithm.
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Study of deposition of thin films by methods of computational physics
Gabriel, Vít ; Hrach, Rudolf (advisor) ; Novotný, Dušan (referee)
This diploma thesis is focused on the design and application of computational physics and image analysis methods. These methods are then used to study early stages of thin films growth. The first section of this thesis is devoted to create molecular dynamics growth model. This model is used to determine the configurations of very small islands containing less than eleven atoms and to describe the coalescence of islands containing hundreds of atoms. The results from the molecular dynamics model are then used as input to the Monte Carlo model. The Monte Carlo model is then used to describe the continuous and pulsed vacuum evaporation methods. The obtained results from the Monte Carlo model are processed by image analysis methods, namely radii distribution and Quadrat Counts method.
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Computational study of initial stages of metal film growth
Soukup, Jindřich ; Hrach, Rudolf (advisor) ; Novotný, Dušan (referee)
This work deals with the description and analysis of image data, which related to the initial stages of the thin film growth. The introductory retrieval section includes a description of thin films and methods of their deposition. The following part is an overview of the growth models of thin layers. The heart of my thesis is the analysis and modification of morphological methods and interpretation of their results. The emphasis is placed on the statistical aspect of methods and their optimal implementation due to the accuracy of the results. The work shows how to modify the radial distribution function and methods based on so-called Voronoi and Delaunay triangulation tessellation so that they can better affect the character of test data. New methods are tested both on the experimental and model data. Then we examine their robustness, sensitivity and their mutual independence. At the conclusion it is introduced and analyzed a new model of thin film growth.
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Study of plasma-solid interaction at medium pressures
Roučka, Štěpán ; Hrach, Rudolf (advisor) ; Novotný, Dušan (referee)
The thesis is aimed at particle simulation of plasma at medium pressures. Main results concern modelling of collisions in particle-in-cell algorithm. Dierent methods of modelling of collisions are discussed and their accuracy and eciency are investigated. Furthermore a new modication of particle-in-cell algorithm for modelling at medium pressures was proposed. Numerical benchmarks in the nal chapter show advantages of the new algorithm.
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