Thermoelectric Properties of Strontium Titanate Superlattices Incorporating Niobium Oxide Nanolayers

被引：10

作者：

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

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

Cha, Dongkyu ^{[1
]}

Tritt, Terry M. ^{[2
]}

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

机构：

[1] KAUST, Thuwal 239556900, Saudi Arabia

[2] Clemson Univ, Dept Phys & Astron, Clemson, SC 29634 USA

来源：

CHEMISTRY OF MATERIALS | 2014年 / 26卷 / 08期

关键词：

2-DIMENSIONAL ELECTRON-GAS; SEEBECK COEFFICIENT; THIN-FILMS; TEMPERATURE; INTERFACES; SRTIO3; OXIDATION; CREATION; PHYSICS; NB2O5;

D O I：

10.1021/cm500646f

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：

A novel superlattice structure based on epitaxial nanoscale layers of NbOx and Nb-doped SrTiO3 is fabricated using a layer-by-layer approach on lattice matched LAO substrates. The absolute Seebeck coefficient and electrical conductivity of the [(NbOx)(a)/(Nb-doped SrTiO3)(b)](20) superlattices (SLs) were found to increase with decreasing layer thickness ratio (a/b ratio), reaching, at high temperatures, a power factor that is comparable to epitaxial Nb-doped SrTiO3 (STNO) films (similar to 0.7 W m(-1) K-1). High temperature studies reveal that the SLs behave as n-type semiconductors and undergo an irreversible change at a varying crossover temperature that depends on the a/b ratio. By use of high resolution X-ray photoelectron spectroscopy and X-ray diffraction, the irreversible changes are identified to be due to a phase transformation from cubic NbO to orthorhombic Nb2O5, which limits the highest temperature of stable operation of the superlattice to 950 K.

引用

页码：2726 / 2732

页数：7

共 46 条

[1] New Synthesis of Nanosized Niobium Oxides and Lithium Niobate Particles and Their Characterization by XPS Analysis [J].