Direct determination of the Fe3+/2+ charge-transition level in BaTiO3 and isovalently substituted Ba0.82Ca0.18Ti0.92Zr0.08O3 by x-ray photoelectron spectroscopy
Abstract
Charge-transition levels of dopants in oxides and other semiconductors are key factors affecting a wide range of material properties. Despite their importance, only very few charge-transition levels are known quantitatively. This work aims to validate the direct experimental determination of charge-transition levels of dopants in oxides by means of x-ray photoelectron spectroscopy (XPS). The approach is used to derive the energy level associated with the Fe3+/2+ transition, which is determined as 2.45±0.05 eV and 2.65±0.05eV above the valence band maximum of BaTiO3 and Ba0.82Ca0.18Ti0.92Zr0.08O3, respectively. The former agrees with thermogravimetric and electric measurements. The results consolidate that XPS is a versatile and reliable technique to experimentally determine charge-transition levels, which can be used to reveal systematic dependencies on concentration, temperature, and host material. It is further demonstrated that high-temperature near-ambient pressure XPS performed at a synchrotron is ideally suited for the determination of charge-transition levels.
Article Details
Journal Info
Journal of Applied Physics
American Institute of Physics
Authors (12)
Savita Chaoudhary
Technical University of Darmstadt, Institute of Materials Science, Electronic Structure of Materials 1 , 64287 Darmstadt,
Anna M. Paulik
Graz University of Technology, Institute for Chemistry and Technology of Materials 2 , 8010 Graz,
Niklas Bertelmann
Technical University of Darmstadt, Institute of Materials Science, Electronic Structure of Materials 1 , 64287 Darmstadt,
Denis Sudarikov
Technical University of Darmstadt, Institute of Materials Science, Electronic Structure of Materials 1 , 64287 Darmstadt,
Pengcheng Hu
Katharina N. S. Lohaus
Technical University of Darmstadt, Institute of Materials Science, Electronic Structure of Materials 1 , 64287 Darmstadt,
Lisanne Gossel
Technical University of Darmstadt, Institute of Materials Science, Electronic Structure of Materials 1 , 64287 Darmstadt,
Melissa A. Larsson
Technical University of Darmstadt, Institute of Materials Science, Electronic Structure of Materials 1 , 64287 Darmstadt,
Hebatallah Ali
Forschungszentrum Jülich GmbH, Institute of Energy Technologies, Fundamental Electrochemistry 3 , 52425 Jülich,
Raoul Blume
Jurij Koruza
Graz University of Technology, Institute for Chemistry and Technology of Materials 2 , 8010 Graz,
Andreas Klein
Tufts Medical Center, Boston, Massachusetts, United States