Thermoelectric performance of Fe2V0.9W0.1Al thin films deposited on n-type Si substrates

Abstract

Fe2V0.9W0.1Al thin films are prepared on n-type Si substrates by means of rf magnetron sputtering with varied substrate temperatures from 743–1043 K, then subsequently annealed for one hour in a vacuum at 1043 K. The thin films deposited at 1043 K are chemically degraded, exhibiting a low Seebeck coefficient, –65 μV K–1, at 330 K. On the other hand, the films deposited at 943 K possess –100 μV K–1 in a Seebeck coefficient at around 330–350 K, which is very similar to the Seebeck coefficient of the bulk W-substituted Fe2VAl that possesses a well-ordered L21 structure. The maximum power factor of 1.6 mWm–1 K–2 was obtained for the sample deposited at 943 K. Accordingly, with the thermal conductivity of 3.5 Wm−1 K−1, the figure of merit reached up to ZT = 0.16, which is comparable with Fe2V0.9W0.1Al of bulks and two times larger than that of the thin films of Si-substituted Fe2VAl.