Surface segregation in Nb-doped BaTiO3 films

被引：14

作者：

Arveux, Emmanuel ^{[1
,2
]}

Payan, Sandrine ^{[1
]}

Maglione, Mario ^{[1
]}

Klein, Andreas ^{[2
]}

机构：

[1] Univ Bordeaux, CNRS, ICMCB, F-33608 Pessac, France

[2] Tech Univ Darmstadt, Inst Mat Sci, D-64287 Darmstadt, Germany

来源：

APPLIED SURFACE SCIENCE | 2010年 / 256卷 / 21期

关键词：

BaTiO3 and titanates; Films; PTCR; Segregation; Surfaces; XPS; SEMICONDUCTING BARIUM TITANATE; CHEMICAL-VAPOR-DEPOSITION; MOLECULAR-BEAM EPITAXY; THIN-FILMS; ELECTRICAL-PROPERTIES; OPTICAL-PROPERTIES;

D O I：

10.1016/j.apsusc.2010.03.146

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

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. (C) 2010 Elsevier B.V. All rights reserved.

引用

页码：6228 / 6232

页数：5

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