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  • Open Access

Direct determination of the charge transition level of dopants in oxides by x-ray photoelectron spectroscopy

Savita Chaoudhary1,*, Andrew Aumen2,*, Elizabeth C. Dickey2, and Andreas Klein1,†

  • *These authors contributed equally to this work.
  • †Contact author: aklein@esm.tu-darmstadt.de
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Phys. Rev. Materials 9, 075002 – Published 9 July, 2025

DOI: https://doi.org/10.1103/mg9m-hk3n

Abstract

Charge transition levels of dopants directly influence material properties, but experimental numbers are difficult to obtain. It will be demonstrated how x-ray photoelectron spectroscopy can be applied to directly determine charge transition levels of dopants in oxides. Oxidizing and reducing treatments induce changes of the Fermi level at the surface, accompanied by changes of the oxidation state of the dopant. The approach is exemplified for 0.2mol% V-doped BaTiO3 bulk ceramics, revealing a V5+/3+ charge transition at a Fermi level ≈0.15eV above the conduction-band minimum. Consequently, V is present as V5+ and acting as a donor in BaTiO3 for most experimental conditions.

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Phys. Rev. Materials 9, 075002– Published 9 July, 2025
  • Received 27 August 2024
  • Accepted 23 June 2025
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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