Study on anisotropy of n-type Mg_3Sb_2-based thermoelectric materials

摘要

The recent discovery of a high thermoelectric figure of merit (ZT) in an n-type Mg3Sb2-based Zintl phase triggered an intense research effort to pursue even higher ZT. Based on our previous report on Mg3.1Nb0.1Sb1.5Bi0.49Te0.01, we report here that partial texturing in the (001) plane is achieved by double hot pressing, which is further confirmed by the rocking curves of the (002) plane. The textured samples of Mg3.1Nb0.1Sb1.5Bi0.49Te0.01 show a much better average performance in the (001) plane. Hall mobility is significantly improved to similar to 105 cm(2) V-1 s(-1) at room temperature in the (001) plane due to texturing, resulting in higher electrical conductivity, a higher power factor of similar to 18 mu W cm(-1) K-2 at room temperature, and also higher average ZT. This work shows that texturing is good for higher thermoelectric performance, suggesting that single crystals of n-type Mg3Sb2-based Zintl compounds are worth pursuing. Published by AIP Publishing.