|
|
Preparation of optical thin films by chemical vapor deposition
Koryčánek, Adam ; Kvapil, Michal (referee) ; Kolíbal, Miroslav (advisor)
This work is focused on the comparison between physical vapor deposition methods of thin antireflective layers and chemical vapor deposition (CVD) methods, for applications in the field of optics. The work begins with basic concepts and principles related to anti-reflective coatings, their deposition and characterization. Furthermore, in the experimental part, the techniques of ellipsometry, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) are used to characterize the properties of the layers and their comparison.
|
|
|
Material Characterization and Modeling of Interband Cascade Light Emitting Diodes
Herzánová, Kristína ; Bastard, Gérald (referee) ; Detz, Hermann (advisor)
Tato práce se zaměřuje na charakterizaci materiálů a ztrátových mechanismů heterostruktur používaných v mezipásových kaskádových zařízeních a na modelování mezi-pásových kaskádových elektroluminiscenčních diod (ICLED). Mezipásová kaskádová zařízení, zejména lasery a elektroluminiscenční diody, mají zásadní význam pro fotonické aplikace ve střední infračervené oblasti vzhledem k jejich efektivitě a možnosti integrace do fotonických obvodů. Studie zahrnuje extrakci materiálových parametrů ze spektroskopické elipsometrie a FTIR měření a rozšíření stávajícího transportního modelu o zářivé rekombinační procesy, konkrétně o spontánní emisi v ICLED. Z různých ztrátových mechanismů v těchto zařízeních byla zvláštní pozornost věnována valenční mezipásové absorpci, která zhoršuje výkon mezipámových kaskádových zařízení v oblasti středních infračervených vlnových délek nad 4 m. Výsledky získané na základě experimentální charakterizace vlnovodů tvořených mezipásovými kaskádovými lasery (ICL) zkoumající jejich přenosové ztráty prokázaly vliv valenční mezipásové absorpce za různých operativních podmínek. Tento výzkum přispívá k optimalizaci struktur mezi-pásových kaskádových struktur, která vede ke zvýšení výkonu a širší použitelnosti v oblasti detekce, monitorování životního prostředí a biomedicínské diagnostiky.
|
|
|
High Temperature Processes in Silicon Solar Cells Production
Frantík, Ondřej ; Hudec, Lubomír (referee) ; Banský,, Juraj (referee) ; Szendiuch, Ivan (advisor)
The thesis is focused on high temperature processes in crystalline solar cells production. Main topic is diffusion of traditional dopants phosphorus and boron. Diffusion processes for creating solar cells are different from classical diffusion in semiconductor industrial. It is reason why the thesis describes crated layers in detail. Knowledge of diffusion processes is used for creating bifacial solar cells and development of a new phosphorus emitter for conventional solar cells. Bifacial cells are a new type of cells. Developed new emitter increases efficiency and decreases cost of solar cells production. Another part the thesis is devoted to the prediction of diffusion processes. New models of phosphorus and boron diffusion for photovoltaic industrial are created in software SILVACO. Models correspond with real results.
|
|
|
Morphology study of ultra thin layers by XPS analysis of multiple peaks of a single element
Pokorný, David ; Šik, Ondřej (referee) ; Polčák, Josef (advisor)
This diploma thesis deals with methodology of thin film thickness determination using X-ray radiation of silver anode which provides radiation with energy of 2984,3 eV. This energy is twice as high as the standard aluminium radiation which allows a measurement of new photoelectron lines with higher bonding energy and it also provides thanks to the higher photoelectron energy greater information depth. In order to get the right results it was necessary to calibrate the spectrometer Kratos Axis Supra in the silver anode mode first and found out the form of the transmission function. The determination of the thickness of the thin layer was demonstrated by the comparation of the ratio of different photoelectron lines intensities with the theoretical model. For that purpose was specifically used the Si 1s and Si 2p peak bound in the substrate in the Si-Si bonding or in the thin oxid layer in the Si-O bonding. The results show that for thin SiO2/Si film thickness determination is the best to use the intensity ratio of only one photoelectron line. A silver anode however provides greater information depth.
|
|
|
Plasma-enhanced chemical vapor deposition using TVS/Ar and TVS/O2 mixtures
Sadílek, Jakub ; Salyk, Ota (referee) ; Čech, Vladimír (advisor)
Tato studie je zaměřena na základní výzkum přípravy a-SiC:H a a-SiCO:H slitin plazmových polymerů pomocí metody plazmochemické depozice z plynné fáze (PE-CVD). Tyto slitiny byly připravovány depozicí z monomeru tetravinylsilanu (TVS) a jeho směsí s kyslíkem a argonem při různých efektivních výkonech pulzního plazmatu. Připravené tenké vrstvy byly za účelem získání závislostí optických, mechanických a chemických vlastností na depozičních podmínkách zkoumány pomocí metod spektros-kopické elipsometrie (ELL), nanoindentace (NI), fotoelektronové spektrometrie (XPS) a Fourierovy transformované infračervené spektrometrie
|
|
| |
|
|
Functionalized nanostructures
Váňa, Rostislav ; Kvapil, Michal (referee) ; Kolíbal, Miroslav (advisor)
This thesis deals with functionalized nanoparticles. In the first part there are mentioned materials suitable for a functionalization, the usage of functionalized nanoparticles in medicine and biochemistry and detection methods of changes of optical properties. In the second part changes of optical properties after functionalization are investigated by spectroscopic ellipsometry and FTIR spectroscopy.
|
|
|
Self-assembled layers based on silicon
Bábík, Adam ; Veselý, Michal (referee) ; Čech, Vladimír (advisor)
Thin film deposition, characterization and properties of self-assembled monolayers based on silicon were studied with emphasis on the SA monolayers deposited from vinyltriethoxysilane and vinyltrichlorsilane. The thesis is aimed at basic properties of the SA monolayer and explanation of its growth. Methods and techniques used for analysis of the monolayer were described as well. Contact angle measurements and an evaluation of the surface free energy are depicted in details. The deposited SA layers were observed with respect to their chemical composition and surface morphology by X-ray photoelectron spectroscopy (XPS), ellipsometry and atomic force microscopy (AFM).
|
|
|
Study of thin film organic materials thickness
Hegerová, Lucie ; Veselý, Michal (referee) ; Zmeškal, Oldřich (advisor)
The diploma thesis deals with the determination of thickness and refractive index of thin organic films using image analysis. In the theoretical part there are described principles of the methods, which are used to prepare the films (spin coating, inkjet printing, vapour deposition), the characteristics of thin films, ways of finding out the thickness and refractive index of substances (weight methods, electric methods, method based on measurement of absorption coefficient of light, interference microscopy, ellipsometry) and also image analysis (harmonic and wavelet analysis). Interference microscope Epival - Interpako (Carl Zeiss Jena), digital camera Nikon Coolpix 5400 and computer were used for the determination of thickness and refractive index. The thicknesses of layers were set on the basis of interference images of edges and grooves – both from the side of the metal contact and the side of underlying glass. The refractive indices of thin layers were then set using the recorded figures. In the final part of the thesis there are discussed the results of interference images photographed along the full length of the aluminium contact which are used for measuring electrical characteristics of DPP structures. The produces are thicknesses and refractive indices of individual layers.
|
|
|
Study of refractive index dispersion dependences with using of interference microscopy
Schmiedová, Veronika ; Veselý, Michal (referee) ; Zmeškal, Oldřich (advisor)
The master´s thesis deals with the study of optical properties of thin transparent layers on the organic materials (PPV, P3HT, TiO2, DPP) and especially with the determination of dispersion dependences of refractive index of prepared thin layers. In the theoretical part there are described principles of deposition thin layers of the analyzed materials and their properties. In addition, there are also described methods of optical properties measurements (optical and interference microscopy and ellipsometry). The combination of interference microscope with digital camera was used for determination of refractive index. The image analysis was used for the determination of parameters (with help of the software HarFA). The images of thin layers surfaces were analyzed from the side of the metal contact as well as from the side of glass. In conclusion, there are presented results of the refractive index of the thin layers obtained from the measured values.
|
guest ::
