High temperature thermoelectric response of double-doped SrTiO$_3$ epitaxial films

TL;DR

This study investigates the thermoelectric properties of double-doped SrTiO$_3$ epitaxial films, revealing their potential for high-temperature energy conversion with a maximum ZT of 0.28 at 873 K.

Contribution

It introduces a method to synthesize double-doped SrTiO$_3$ epitaxial films and characterizes their thermoelectric performance at high temperatures, showing comparable thermopower to single crystals.

Findings

Thermoelectric figure of merit ZT reaches 0.28 at 873 K.

Double doping with La and oxygen vacancies enhances thermoelectric response.

Thermopower values are comparable to single crystal studies.

Abstract

SrTiO$_3$ is a promising $n$-type oxide semiconductor for thermoelectric energy conversion. Epitaxial thin films of SrTiO$_3$ doped with both La and oxygen vacancies have been synthesized by pulsed laser deposition (PLD). The thermoelectric and galvanomagnetic properties of these films have been characterized at temperatures ranging from 300 K to 900 K and are typical of a doped semiconductor. Thermopower values of double-doped films are comparable to previous studies of La doped single crystals at similar carrier concentrations. The highest thermoelectric figure of merit ($ZT$) was measured to be 0.28 at 873 K at a carrier concentration of $2.5\times10^{21}$ cm$^{-3}$.