Improvement of power factor in the room temperature range of Mg 2 Sn 1− x Ge x

Abstract In this work, we investigated the influence of the Mg/Sn supply ratio into Mg 2 Sn thin film, deposited on Al 2 O 3 (0001) (sapphire c -plane) substrate using molecular beam epitaxy (MBE), as well as the effect of incorporating Ge. We demonstrated that a low ratio of Sn to Mg improved the thin film’s quality, while the incorporation of Ge atoms (into the Sn sites) resulted in superior thermoelectrical properties (p-type). Our results suggest that the improvement of the thermoelectric properties could be associated with point defects in the Mg site. The optimal power factor value obtained was 2.7 × 10 −4 W ∙ m −1 ∙ K −1 at 300 K for the Mg 2 Sn 0.8 Ge 0.2 .