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Electronic Properties of Metal Oxide Films Studied by Core Level Spectroscopy

<p>In this dissertation core level electron spectroscopy has been employed to study various aspects of metal oxide films grown under ultra-high vacuum conditions. </p><p>Studies on <i>in situ</i> ion insertion of lithium into thin TiO<sub>2</sub> systems were performed. The electronic and geometric properties are investigated in detail, along with an estimation of charge transfer from Li to Ti. </p><p>A detailed study of chemical vapour deposition of ZrO<sub>2</sub> on Si(100)-(2x1) was performed. ZrO<sub>2</sub> is found to be an insulator, i.e. its electronic levels are decoupled from the substrate and the Zr levels are best referenced to the local vacuum level. The alignment of the valence and conduction band has been determined. </p><p>Combinatorial chemical vapour deposition of TiO<sub>2</sub> and ZrO<sub>2</sub> on Si(100)-(2x1) was realized. A film with graded stoichiometry consisting of pure TiO<sub>2</sub> and ZrO<sub>2</sub> on the opposing ends and mixed composition of both oxides in the middle was obtained. A detailed study of the electronic levels revealed that ZrO<sub>2</sub> remains an insulator in the monolayer regime and that modification of ZrO<sub>2</sub> with a small amount of TiO<sub>2</sub> leads to a more symmetric alignment of the bands relative to Si. </p><p>The influence of a core hole on the O 1s x-ray absorption spectrum in TiO<sub>2</sub> and ZrO<sub>2</sub> is elucidated. Supported by O 1s photoemission measurements and <i>ab initio</i> calculations it is concluded that the static final state picture as well as dynamical threshold effects must be considered in order to determine the location of the conduction band minimum within the XAS framework. </p><p>Finally a Co modified Co:ZnO film was shown to display ferromagnetic properties. It could be evidenced that Co with oxygen as nearest neighbours was responsible for the magnetism and not metallic Co.</p>

Identiferoai:union.ndltd.org:UPSALLA/oai:DiVA.org:uu-7180
Date January 2006
CreatorsRichter, Jan Hinnerk
PublisherUppsala University, Department of Physics, Uppsala : Acta Universitatis Upsaliensis
Source SetsDiVA Archive at Upsalla University
LanguageEnglish
Detected LanguageEnglish
TypeDoctoral thesis, comprehensive summary, text
RelationDigital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, 1651-6214 ; 228

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