Thermoelectric properties of thin film materials : influence of the substrate and contact resistance
Résumé
Semiconductor or oxide materials are today in the scope in plural technological domains and especially for the energy harvesting applications. Thermoelectric conversion is always driven by the famous Bi2Te3 material with figure of merit ZT above the unity. Nevertheless, according to chemical and electrical properties tuning, semiconductors and oxides became relevant candidates. For a better accuracy on the thermoelectric properties, we developed a micro-ZT-meter with a simultaneous measurement of Seebeck, electrical conductivity and, recently, the thermal conductivity. Besides, an evaluation of the contact resistance between electrodes (made by magnetron sputtering technique) and thin film material is conducted to evaluate the influence of the micro-thermopiles within the structure.
We are actually studying thin film materials deposited on silicon and silicon dioxide, in order to correlate the material characteristics with the thermoelectric properties. Electrodes such as platinum, nickel and gold were used. As already shown on other material in the literature, we emphasized on the influence of the substrate on the Seebeck coefficient.