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An influence of electron beam on thin oxide films
Kostyal, Michal ; Průša, Stanislav (referee) ; Čechal, Jan (advisor)
This bachelor work deals with a study of the influence of electron beam of scanning electron microscope on the surface of the SiO2/Si (100) – sample. In the work the electron and atomic force microscopy briefly described. The main objective of experimental part is to describe variation in the brightness of sample SiO2/Si (100) in Scanning electron microscope images. In this study is found that on the sample surface are created objects few nm high. The rest of the work is then devoted to measuring the dependence of the object’s high on different variables. Experiments are generally based on the selective irradiation of the sample surface by scanning electron microscope, measurement of irradiated parts using atomic force microscope and evaluation in the application Gwyddion.
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Metal-organic networks on graphene surfaces
Kurowská, Anna ; Průša, Stanislav (referee) ; Čechal, Jan (advisor)
Molecular self-assembly is a spontaneous association of molecules and atoms into well-defined supramolecular structures. Understanding this process is key for preparation of structures with atomic precision. This thesis studies the supramolecular structure of tetrakyanochinodimetan molecules (TCNQ) and iron atoms on graphene grown on iridium crystal with the (111) surface. The surface analysis was performed by scanning tunneling microscopy, low-energy electron microscopy and x-ray photoelectron spectroscopy. The thesis introduces the growth process of a good quality graphene on Ir(111) and the synthesis of Fe-TCNQ networks 20 nm x 20 nm large and describes their structural properties. Three preferential orientations of Fe-TCNQ on graphene were identified. The networks will be used in follow-up studies targeting their magnetic properties.
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Charge Exchange processes involved in projectile-target interaction at low energy range studied by HS-LEIS
Bábík, Pavel ; Král, Jaroslav (referee) ; Průša, Stanislav (advisor)
This diploma thesis is focused on the charge exchange processes between projectile and target studied by the Low Energy Ion Scattering (LEIS) technique. Basic premise to investigate charge exchange processes is correct cleaning processes and proper settings of experimental instrument Qtac 100 placed in the Central European Institute of Technology (CEITEC) in Brno. Ion fraction expresses neutralization rate of the projectile. The parametr is investigated for clean and oxidized polycrystalline copper. Oxygen presence performs a significant part of reionization of backscattered neutralized projectiles.
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Studies of molecular beams of organic materials
Maniš, Jaroslav ; Průša, Stanislav (referee) ; Mach, Jindřich (advisor)
This bachelor's thesis deals with assembling of low-temperature efussion cell which is suitable for deposition of organic materials. The calibration of operating temperature of effusion cell is performed. Depositions of organic semiconductor material are realized. Morphology of surface of thin film is studied in AFM and SEM microscope. In the paper background research on the utilization of organic materials in semiconductor industry is presented.
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Surface contamination of optical elements studied by Low Energy Ion Scattering LEIS
Sekula, Filip ; Kolíbal, Miroslav (referee) ; Průša, Stanislav (advisor)
This thesis focuses on study of surface contamination of optical elements using the low energy ion scattering method, LEIS. Presence of surface contaminations on optical elements has a negative contribution on thin layers that are applied upon them. The contamination can occur between the steps of manufacturing process. By determining the composition of the contaminations it could be possible to increase effectiveness during the growth of thin layers. Measurement is realised on right angle prisms at room temperature. We also focus on construction of sample holder that would allow heating of samples in the preparation chamber. Later we measure reference spectra for quantification of surface contamination.
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Metal-organic interface for effective charge transfer
Mrhačová, Petra ; Průša, Stanislav (referee) ; Procházka, Pavel (advisor)
This bachelor thesis deals with the analysis of benzene-1,3,5-tricarboxylic acid (TMA) molecules on a silver crystal with (111) surface termination. After the deposition of the molecules on the substrate, a fully protonated layer ( phase) is formed. Further substrate annealing induces a deprotonation process, which leads to the formation of another and phases. The different arrangements of the molecules were studied in ultra-high vacuum conditions by low-energy electron microscope (LEEM), scanning tunneling microscope (STM), and by low-energy electron diffraction (LEED). The application potential of these layers is discussed.
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