Castro Chavarria, Christopher (2022)
Charged defects in BaTiO₃ thin films.
Technische Universität Darmstadt
doi: 10.26083/tuprints-00021392
Ph.D. Thesis, Primary publication, Publisher's Version
Text
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Item Type: | Ph.D. Thesis | ||||
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Type of entry: | Primary publication | ||||
Title: | Charged defects in BaTiO₃ thin films | ||||
Language: | English | ||||
Referees: | Prellier, Dr. Wilfrid ; Maglione, Dr. Mario ; Klein, Prof. Dr. Andreas ; Donner, Prof. Dr Wolfgang ; Rödel, Prof. Dr. Jürgen ; Béchou, Prof. Dr. Laurent ; Besland, Dr. Marie-Paule ; Remiens, Prof. Dr. Denis ; Bouyssou, Dr. Emilien | ||||
Date: | 2022 | ||||
Place of Publication: | Darmstadt | ||||
Collation: | 172 Seiten | ||||
Date of oral examination: | 9 November 2021 | ||||
DOI: | 10.26083/tuprints-00021392 | ||||
Abstract: | The work presented here focuses on the study of doped BaTiO₃ (BTO) thin films deposited by magnetron sputtering. Due to its ferroelectric properties and its high dielectric permittivity, BTO is used as a tunable capacitor or also in non-volatile memories (FeRAM). Nevertheless, these properties are strongly degraded when deposed as thin films as a results of the extrinsic interface effects. The strategy adopted in this study to improve these dielectric properties was to control the charged defects at the interface by multilayered doped BTO thin films (Mn, Nb and La). Studies on monodoped thin films and multilayers have shown that the carefully designed interfaces lead to increasing relative permittivity of BTO thin films, contradicting the common belief that interfaces behave like dead layers. The use of different techniques such as Electron Paramagnetic Resonance (EPR), dielectric impedance and in particular X-ray Photoelectron Spectroscopy (XPS) and Time-of-Fligh Secondary Ion Mass Spectroscopy (ToF-SIMS) have enabled us to relate the different physical and chemical aspects such as the Fermi level position and the defect chemistry at the interfaces of BTO multilayers. In addition, we have studied the particularities of the Fermi level position of Mn-doped layers. Charging phenomena or even surface photovoltage induce an artificial change in the Fermi level of the Mn-doped BTO when deposited on various substrates. Finally, we implemented a deposition technique using oxygen plasma which made it possible to lower the Fermi level position towards the valence band of Mn doped BTO. |
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Uncontrolled Keywords: | Barium titanate, thin films, dielectric, XPS, ToF-SIMS, charged defects, doping, leakage currents, EPR Bariumtitanat, Dünnschichten, Dotierung, Defekte, dielektrische Eigenschaften, Elektronenspektroskopie, Elektronen-Spin-Resonanz, Massenspektrometrie | ||||
Status: | Publisher's Version | ||||
URN: | urn:nbn:de:tuda-tuprints-213925 | ||||
Classification DDC: | 500 Science and mathematics > 500 Science 500 Science and mathematics > 530 Physics 500 Science and mathematics > 540 Chemistry |
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Divisions: | 11 Department of Materials and Earth Sciences > Material Science > Electronic Structure of Materials (ESM) | ||||
Date Deposited: | 27 Jul 2022 12:12 | ||||
Last Modified: | 26 Aug 2022 08:16 | ||||
URI: | https://tuprints.ulb.tu-darmstadt.de/id/eprint/21392 | ||||
PPN: | 497916266 | ||||
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