Transparent niobium-doped titanium dioxide thin films with high Seebeck coefficient for thermoelectric applications

This work reports the production and characterization of optically transparent Nb-doped TiO2 thin films with enhanced thermoelectric properties deposited on glass and Si by reactive d.c. magnetron sputtering in high vacuum. The purpose of these films is to harvest thermal energy from the environment...

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Detalles Bibliográficos
Autores: Ribeiro, Joana M., Correia, Filipe C., Rodrigues, F. J., Reparaz, J. Sebastian, Goñi, Alejandro R., Tavares, C. J.
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2021
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/255524
Acceso en línea:http://hdl.handle.net/10261/255524
Access Level:acceso abierto
Palabra clave:Niobium
TiO2
Seebeck effect
Figure of merit
Thermoelectric
Thin film
Descripción
Sumario:This work reports the production and characterization of optically transparent Nb-doped TiO2 thin films with enhanced thermoelectric properties deposited on glass and Si by reactive d.c. magnetron sputtering in high vacuum. The purpose of these films is to harvest thermal energy from the environment and convert it to electrical energy. Several process parameters, such as reactive and working gas flow rate, deposition temperature, target current density and post-annealing conditions, directly affect the morphology and crystalline structure of the thin films. The optimization of these parameters results in thin films with thickness of 120–300 nm, maximum average optical transmittance in the visible range of 73%, n-type electrical resistivity of 0.05 Ω·cm, thermal conductivity around 1.5 W·m−1·K−1 and a maximum absolute Seebeck coefficient of 223 μV·K−1. The resulting maximum thermoelectric power factor is 60 μW·K−2·m−1 and the maximum thermoelectric figure of merit is 0.014. Hence, modifying the optical, electric, thermal and thermoelectric properties of the thin films enables their suitability for applications as transparent electrodes in photovoltaic systems and touch displays, amongst other devices.