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Surface segregation in Nb-doped BaTiO3 films

Arveux, E. and Payan, S. and Maglione, M. and Klein, Andreas (2010):
Surface segregation in Nb-doped BaTiO3 films.
In: Applied Surface Science, pp. 6228-6232, 256, (21), ISSN 01694332,
[Online-Edition: http://dx.doi.org/10.1016/j.apsusc.2010.03.146],
[Article]

Abstract

We have used in situ photoemission spectroscopy to investigate Niobium doping in polycristalline BaTiO3. The valence band maximum position progressively shifts from 2.5 eV for undoped to 2.84 eV for Nb-doped films. Ceramics and single crystal have been investigated for comparison with thin films. Nb-doped BaTiO3 ceramics and Nb-doped SrTiO3 single crystal show higher Fermi level position indicating that our doped films are less conducting regarding their bulk parents. This was confirmed by impedance spectroscopy under variable temperature. Large amount of niobium is clearly observable at surface but the amount of dopant is drastically reduced below the near-surface region, as evidenced by depth profile. Therefore, we provide evidence of surface segregation which would explain the contrasted resistivity values reported in literature for such donor-doped films.

Item Type: Article
Erschienen: 2010
Creators: Arveux, E. and Payan, S. and Maglione, M. and Klein, Andreas
Title: Surface segregation in Nb-doped BaTiO3 films
Language: English
Abstract:

We have used in situ photoemission spectroscopy to investigate Niobium doping in polycristalline BaTiO3. The valence band maximum position progressively shifts from 2.5 eV for undoped to 2.84 eV for Nb-doped films. Ceramics and single crystal have been investigated for comparison with thin films. Nb-doped BaTiO3 ceramics and Nb-doped SrTiO3 single crystal show higher Fermi level position indicating that our doped films are less conducting regarding their bulk parents. This was confirmed by impedance spectroscopy under variable temperature. Large amount of niobium is clearly observable at surface but the amount of dopant is drastically reduced below the near-surface region, as evidenced by depth profile. Therefore, we provide evidence of surface segregation which would explain the contrasted resistivity values reported in literature for such donor-doped films.

Journal or Publication Title: Applied Surface Science
Volume: 256
Number: 21
Uncontrolled Keywords: BaTiO3 and titanates; Films; PTCR; Segregation; Surfaces; XPS
Divisions: 11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Surface Science
Zentrale Einrichtungen
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > B - Characterisation
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > B - Characterisation > Subproject B7: Polarisation and charging in electrical fatigue ferroelectrics
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres
DFG-Collaborative Research Centres (incl. Transregio)
Date Deposited: 05 Oct 2011 09:17
Official URL: http://dx.doi.org/10.1016/j.apsusc.2010.03.146
Additional Information:

SFB 595 B7

Identification Number: doi:10.1016/j.apsusc.2010.03.146
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