Abstract
Amorphous FeVSb-based thin films doped with Ti are deposited by magnetron sputtering. The microstructure, thermal stability, and thermoelectric properties of the films are systematically investigated. The as-deposited (FeVSb)1−xTix films possess an amorphous structure that is thermally stable up to 473 K. The non-doped FeVSb film is an n-type semiconductor. When Ti is doped into the FeVSb film, the (FeVSb)1−xTix films with x from 0.02 to 0.10 are p-type semiconductors. The thermal conductivity values of the FeVSb and (FeVSb)0.94Ti0.06 films measured by the suspended thermal bridge method are 1.18 and 0.93 W m−1 K−1 at 300 K, respectively, which are much lower than those of half-Heusler crystalline bulk materials due to the amorphous structure of these films. The thermoelectric figure of merit ZT is calculated to be 0.09 and 0.23 at 300 K for the FeVSb and (FeVSb)0.94Ti0.06 films, respectively. A planar thermoelectric generator (TEG) with 4 thermocouples based on amorphous (FeVSb)1−xTix films is fabricated. The maximum output power and open-circuit voltage of the TEG are 248 nW and 15.4 mV at a temperature difference of 59.4 K. Our results demonstrate that the amorphous (FeVSb)1−xTix film with ultra-low thermal conductivity and high ZT at room temperature is a high-performance TE material for TEGs.
Original language | English |
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Pages (from-to) | 11435-11445 |
Number of pages | 11 |
Journal | Journal of Materials Chemistry A |
Volume | 6 |
Issue number | 24 |
Early online date | 18 May 2018 |
DOIs | |
Publication status | Published - 2018 |
Externally published | Yes |
Funding
This work was financially supported by the National Natural Science Foundation of China (Grant No. 51572149), National Key Research and Development Program of China (Grant No. 2016YFA0201003), National Basic Research Program of China (Grant No. 2013CB632504), Fund of Key Laboratory of Advanced Materials of Ministry of Education (Grant No. 2017AML11) and Research Grants Council of the Hong Kong Special Administrative Region, China, under the General Research Fund (RGC Ref No. 14238416).