University of Oulu

Tyunina, M., Chvostova, D., & Dejneka, A. (2019). Optical revelation of defects in epitaxial barium titanate films. Physical Chemistry Chemical Physics, 21(15), 7874–7878. https://doi.org/10.1039/c9cp00923j

Optical revelation of defects in epitaxial barium titanate films

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Author: Tyunina, M.1,2; Chvostova, D.2; Dejneka, A.2
Organizations: 1Microelectronics Research Unit, Faculty of Information Technology and Electrical Engineering, University of Oulu, P. O. Box 4500, FI-90014, Finland
2Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, 18221 Prague, Czech Republic
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 2.7 MB)
Persistent link: http://urn.fi/urn:nbn:fi-fe2019061921017
Language: English
Published: Royal Society of Chemistry, 2019
Publish Date: 2019-06-19
Description:

Abstract

Allying epitaxial strain and synthesis conditions allows for the introduction of specific point defects in perovskite oxide films. In ferroelectric films, such defects lead to essential polar and electronic properties, which can enable advanced applications. Here, to elucidate the nature of the defects, optical constants are investigated in the spectral range of 0.7–8.8 eV in epitaxial ferroelectric BaTiO₃ films, which are synthesized under different conditions. It is demonstrated that oxygen-vacancy-related defects are responsible for a peculiar transition below the bandgap at ∼2.7–2.9 eV and significant blueshifts of ∼0.3–0.4 eV of the gap and the main interband transitions. These observations suggest that the defects are dipolar complexes comprising titanium cations and oxygen vacancies (Ti³⁺–Vₒ).

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Series: PCCP. Physical chemistry chemical physics
ISSN: 1463-9076
ISSN-E: 1463-9084
ISSN-L: 1463-9076
Volume: 21
Issue: 15
Pages: 7874 - 7878
DOI: 10.1039/c9cp00923j
OADOI: https://oadoi.org/10.1039/c9cp00923j
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
Subjects:
Funding: The authors are thankful to T. Kocourek, M. Jelinek, and O. Pacherova for sample preparation and structural characterization. The authors acknowledge support from the Czech Science Foundation (Grant No. 19-09671S) and the European Structural and Investment Funds and the Ministry of Education, Youth and Sports of the Czech Republic through Programme ‘‘Research, Development and Education’’ (Project No. SOLID21 – CZ.02.1.01/0.0/0.0/16_019/0000760).
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