Exploring tantalum as a potential dopant to promote the thermoelectric performance of zinc oxide

Arias-Serrano, Blanca I. ; Xie, Wenjie ; Aguirre, Myriam H. (Universidad de Zaragoza) ; Tobaldi, David M. ; Sarabando, Artur R. ; Rasekh, Shahed ; Mikhalev, Sergey M. ; Frade, Jorge R. ; Weidenkaff, Anke ; Kovalevsky, Andrei V.

Resumen: Zinc oxide (ZnO) has being recognised as a potentially interesting thermoelectric material, allowing flexible tuning of the electrical properties by donor doping. This work focuses on the assessment of tantalum doping effects on the relevant structural, microstructural, optical and thermoelectric properties of ZnO. Processing of the samples with a nominal composition Zn1-xTaxO by conventional solid-state route results in limited solubility of Ta in the wurtzite structure. Electronic doping is accompanied by the formation of other defects and dislocations as a compensation mechanism and simultaneous segregation of ZnTa2O6 at the grain boundaries. Highly defective structure and partial blocking of the grain boundaries suppress the electrical transport, while the evolution of Seebeck coefficient and band gap suggest that the charge carrier concentration continuously increases from x = 0 to 0.008. Thermal conductivity is almost not affected by the tantalum content. The highest ZT~0.07 at 1175 K observed for Zn0.998Ta0.002O is mainly provided by high Seebeck coefficient (-464 µV/K) along with a moderate electrical conductivity of ~13 S/cm. The results suggest that tantalum may represent a suitable dopant for thermoelectric zinc oxide, but this requires the application of specific processing methods and compositional design to enhance the solubility of Ta in wurtzite lattice.

Idioma: Inglés

DOI: 10.3390/ma12132057

Año: 2019

Publicado en: Materials 12, 13 (2019), 2057 [11 pp.]
ISSN: 1996-1944

Factor impacto JCR: 3.057 (2019)

Categ. JCR: MATERIALS SCIENCE, MULTIDISCIPLINARY rank: 132 / 314 = 0.42 (2019) - Q2 - T2

Factor impacto SCIMAGO: 0.647 - Materials Science (miscellaneous) (Q2) - Condensed Matter Physics (Q2)

Financiación: info:eu-repo/grantAgreement/ES/FEDER/POCI-01-0145-031875
Financiación: info:eu-repo/grantAgreement/ES/FEDER/UID/CTM/50011/2019
Financiación: info:eu-repo/grantAgreement/EC/H2020/734187/EU/Spin conversion, logic storage in oxide-based electronics/SPICOLOST

Tipo y forma: Article (Published version)

Área (Departamento): Área Física Materia Condensada (Dpto. Física Materia Condensa.)