Sabina KUPRENAITE: "Heterogeneous integration of functional thin films for acoustic and optical devices"

PhD Works : "Heterogeneous integration of functional thin films for acoustic and optical devices"

Abstract : The control of microstructure and surface morphology is essential for the thin films to be applied in optical and acoustic devices. Thin films of TiO₂, LaNiO₃ and ZnO and their heterostructures in this work were obtained by radio frequency (RF) magnetron sputtering and metalorganic chemical vapor deposition (MOCVD) techniques. The optimization of deposition parameters, such as temperature, total chamber pressure, O2 partial pressure and growth rate, led to high structural quality of functional thin films and their heterostructures. The orientation of epitaxial ZnO and TiO₂ thin films was tuned not only through lattice matching with various substrates, but as well through deposition conditions. The optical quality of TiO₂ films was mostly optimized through elimination of microstructural defects and increasing oxygen non-stoichiometry. It was shown that microstructural and lattice defects in polycrystalline and epitaxial films played a key role in optical propagation losses. Effect of substrate polarity on the structural, optical and acoustic properties of ZnO-based thin films was studied, as well. The sacrificial and/or seed layers were identified for heterogeneous intégration of functional acoustical and optical films with semiconductor substrates.

Composition of the jury : 

- M. WEISS François - Directeur de Recherche CNRS, LMGP- MINATEC - Reporter
- M. JUKNA Arturas - Professeur des Universités, Vilnius Gediminas Technical University - Reporter
- M. BANYS Juras - Professeur des Universités, Vilnius University - Reviewer
- M. BOULET Pascal - Ingenieur de recherche CNRS, Université de Lorraine - Reviewer
- M. MARTIN Nicolas - Professeur des Universités, ENSMM - Reviewer
- M. SANTISO José - CSIC Tenured Scientist, Universitat Autònoma de Barcelona - Reviewer
- Mme. BARTASYTE Ausrine - Ingénieur de Recherche HDR, E.N.S.M.M - PhD Director
- M. ABRUTIS Adulfas - Professeur des Universités, Vilnius University - Phd Co-Supervisor

Localization : Amphithéâtre J-J Gagnepain à TEMIS Sciences, 15B, Avenue des Montboucons - Besançon