Preparation and thermoelectric properties of heavily Nb-doped SrO(SrTiO3)1 epitaxial films

Abstract

We report the epitaxial film growth, by pulsed laser deposition, of c-axis-oriented Nb-doped SrO(SrTiO3)1 films having a K2NiF4-type structure and their thermoelectric properties over a wide temperature range, from 20 to 800 K. High-resolution x-ray diffraction and reflection high energy electron diffraction patterns revealed that the films were grown heteroepitaxially on the (001) face of the LaAlO3 substrate. The thermoelectric properties of the Nb-doped SrO(SrTiO3)1 epitaxial films were improved in terms of power factor compared to those for polycrystalline Nb-doped SrO(SrTiO3)1. A theoretical analysis of the transport parameters revealed that the intrinsic transport occurred predominantly in the SrTiO3 layers.