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X‐ray absorption and resonant photoemission studies of electroforming process in Fe‐doped SrTiO 3 epitaxial films
Author(s) -
Kubacki Jerzy,
Kajewski Dariusz,
Koehl Annemarie,
Lenser Christian,
Dittmann Regina,
Szade Jacek
Publication year - 2015
Publication title -
x‐ray spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.447
H-Index - 45
eISSN - 1097-4539
pISSN - 0049-8246
DOI - 10.1002/xrs.2637
Subject(s) - doping , electroforming , electronic structure , materials science , fermi level , band gap , x ray photoelectron spectroscopy , analytical chemistry (journal) , titanium , epitaxy , valence (chemistry) , condensed matter physics , chemistry , optoelectronics , nanotechnology , nuclear magnetic resonance , electron , metallurgy , physics , organic chemistry , layer (electronics) , quantum mechanics , chromatography
This work presents the results of the electronic structure investigations of epitaxial 2% Fe‐doped SrTiO 3 film. The electroforming process of the film was performed inside the ultra‐high vacuum test chamber by applying positive 10 V bias to the film with the use of the aluminium ‘brush’ electrode. The X‐ray absorption and resonant photoemission methods were used to study the effect of Fe doping and electroformation on the electronic structure of the SrTiO 3 films. Analysis of the valence band revealed the increase of the photoelectron intensity in the band gap region as the result of Fe doping. Electroformation caused a slight variation of the iron originating electronic states derived from the resonant photoemission, which can probably be related to the increasing contribution from the Fe2+ ions with respect to the Fe3+ ones. The titanium partial density of states showed an increase in the band gap region after the electroformation process. The significant decreases of the iron concentration derived from the photoemission spectra were found after electroforming procedure. The observed changes can be related to the increased migration of oxygen and possibly also iron ions provoked by a strong electric field applied by the electrode, eventually leading to modification of the local electronic structure. Copyright © 2015 John Wiley & Sons, Ltd.