Microelectronics meets catalysis: An interdisciplinary approach on the structure-property relationship of single crystalline Ce1-xPrxO2-δ films on Si(111) ; Mikroelektronik begegnet Katalyse: Ein interdisziplinärer Ansatz zur Struktur-Eigenschaftsbeziehung von einkristallinen Ce1-xPrxO2-δ Filmen auf Si(111)

Motivation: Ceria attracted a lot of attention for microelectronics (e.g. high-k gate oxide, buffer layer for heteroepitaxy) and catalysis (e.g. selectiveoxidative and dehydrogenating reactions), due to its inherent structural (similar crystal structures and small lattice mismatch with respect to silicon) and electronic (Ce4+/Ce3+ valence state variation and formation of oxygen vacancies) properties. Thus, single crystalline epitaxial ceria thin films are well investigated. Although, the neighbouring rare earth oxide, praseodymia, exhibits similar properties, this system is much less studied due to its complex phase diagram. Since both oxides exhibit a flexible structural (polymorphism) and electronic (valence state variation) behavior, it is of ongoing interest to study ceria-praseodymia mixed oxide thin films, in order to tune and improve certain characteristics for the respective applications in the field of microelectronics and catalysis. Goal: Therefore, the goal of this doctoral thesis is to grow and characterize in an interdisziplinary approach single crystalline and epitaxial, binary and ternary Ce1-xPrxO2-δ thin films in order to allocate high quality samples for further fundamental studies, devoted to the structural and electronic properties in the field of microelectronics and catalysis. Experimental: Such single crystalline and epitaxial Ce1-xPrxO2-δ thin films were grown on a Si(111) substrate by molecular beam epitaxy. An in-situ control of the crystal growth quality was achieved by reflection high-energery electron diffraction. A detailed structure characterization study was carried out by laboratory and synchrotron based X-ray scattering. Additionally, transmission electron microscopy gives a highly resolved structural insight. The structural characterization was supported by theoretical ab-initio calculations. To determine the stoichiometries and valence states of the ternary mixed oxide compounds, X-ray photoelectron spectroscopy was performed. The microscopic defect structure was investigated ...