The electronic properties of SrTiO3‑δ with oxygen vacancies or substitutions
|Author:||Rusevich, L. L.1; Tyunina, M.2,3; Kotomin, E. A.1,4;|
1Institute of Solid State Physics, University of Latvia, Kengaraga Str. 8, Riga, 1063, Latvia
2Microelectronics Research Unit, Faculty of Information Technology and Electrical Engineering, University of Oulu, P. O. Box 4500, 90014, Oulu, Finland
3Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, 18221, Prague, Czech Republic
4Max Planck Institute for Solid State Research, Heisenberg Str. 1, 70569, Stuttgart, Germany
|Online Access:||PDF Full Text (PDF, 1.9 MB)|
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe2022030321648
|Publish Date:|| 2022-03-03
The electronic properties, including bandgap and conductivity, are critical for nearly all applications of multifunctional perovskite oxide ferroelectrics. Here we analysed possibility to induce semiconductor behaviour in these materials, which are basically insulators, by replacement of several percent of oxygen atoms with nitrogen, hydrogen, or vacancies. We explored this approach for one of the best studied members of the large family of ABO₃ perovskite ferroelectrics — strontium titanate (SrTiO₃). The atomic and electronic structure of defects were theoretically investigated using the large-scale first-principles calculations for both bulk crystal and thin films. The results of calculations were experimentally verified by studies of the optical properties at photon energies from 25 meV to 8.8 eV for in-situ prepared thin films. It was demonstrated that substitutions and vacancies prefer locations at surfaces or phase boundaries over those inside crystallites. At the same time, local states in the bandgap can be produced by vacancies located both inside the crystals and at the surface, but by nitrogen substitution only inside crystals. Wide-bandgap insulator phases were evidenced for all defects. Compared to pure SrTiO₃ films, bandgap widening due to defects was theoretically predicted and experimentally detected.
|Type of Publication:||
A1 Journal article – refereed
|Field of Science:||
216 Materials engineering
213 Electronic, automation and communications engineering, electronics
This article was funded by FLAG-ERA JTC project To2Dox, Czech Science Foundation (Grant no. 19-09671S), Ministry of Education, Youth and Sports of the Czech Republic, programme “Research, Development and Education” (Grant no. SOLID21 CZ.02.1.01/0.0/0.0/16-019/0000760).
© The Author(s) 2021. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4 0/.