Effect of oxygen vacancy distribution on the thermoelectric properties of La-doped SrTiO3 epitaxial thin films

被引：17

作者：

Kumar, S. R. Sarath ^{[1
]}

Abutaha, A. I. ^{[1
]}

Hedhili, M. N. ^{[1
]}

Alshareef, H. N. ^{[1
]}

机构：

[1] King Abdullah Univ Sci & Technol, Thuwal 239556900, Saudi Arabia

来源：

JOURNAL OF APPLIED PHYSICS | 2012年 / 112卷 / 11期

关键词：

ROOM-TEMPERATURE; EFFECTIVE-MASS; TRANSPORT; ELECTRONS; TITANATE; PHYSICS; POWER;

D O I：

10.1063/1.4767840

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

A detailed study of the role of oxygen vacancies in determining the effective mass and high temperature (300-1000 K) thermoelectric properties of La-doped epitaxial SrTiO3 thin films is presented. It is observed that at intermediate temperatures, a transition from degenerate to non-degenerate behavior is observed in the Seebeck coefficient, but not electrical conductivity, which is attributed to heterogeneous oxygen non-stoichiometry. Heikes formula is found to be invalid for the films with oxygen vacancies. By fitting the spectroscopic ellipsometry (SE) data, obtained in the range 300-2100 nm, using a Drude-Lorentz dispersion relation with two Lorentz oscillators, the electrical and optical properties of the films are extracted. Using the excellent agreement between the transport properties extracted from SE modeling and direct electrical measurements, we demonstrate that an increase in concentration of oxygen vacancies results in a simultaneous increase of both carrier concentration and electron effective mass, resulting in a higher power factor. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4767840]

引用

页数：7

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