The Influence of Weak Tin Doping on the Thermoelectric Properties of Zinc Antimonide

摘要

ZnSb would be a good thermoelectric material with carrier concentration above 10(19)/cm(3), but unfortunately this has been shown to be difficult to achieve, particularly with Sn as a dopant. Two series ZnSb samples doped with Sn and ZnSn were prepared using hot-pressing technics, and their thermoelectric properties were investigated in the temperature range from 300 K to 700 K. The tin content of the samples was in the range from 0.1 to 0.5 at.%. Surprisingly, samples with lower tin content achieved higher carrier concentration, which is beneficial for thermoelectric performance. Samples doped with 0.1 at.% Sn achieved Hall carrier concentration above 1 x 10(19)/cm 3, reaching ZT of 0.9, while for samples doped with 0.5 at.% Sn, the Hall carrier concentration was close to the hole concentration of pure ZnSb. Also, by analyzing hysteresis present in the heating-cooling cycles, we conclude that the role of intrinsic defects in ZnSb is important and that these defects clearly determine the ability of ZnSb to achieve ZT near 1.