碲化铋基热电半导体晶体空间生长

碲化铋基热电半导体是中低温区高性能热电材料，在热电致冷、电子器件精确控温领域获得了重要应用，且在更多领域具有广泛应用前景.碲化铋基材料通常采用区熔法制备，材料的性能优值ZT约为0.8.应用要求进一步提高其ZT值.合金化和掺杂优化是提高碲化铋基材料性能的有效途径，但会使得材料的化学成分越来越复杂.重力条件下区熔的固有问题是，重力导致的浮力对流和壁附效应凸显，使区熔碲化铋基材料成分和性能波动较大.空间微重力可以消除重力导致的浮力对流和壁附效应，有望提高碲化铋基材料的成分均匀性和热电性能.本文根据碲化铋基材料空间微重力下区熔生长研究状况，对实践十号科学实验卫星和天宫二号空间实验室将开展的碲化铋基材料空间微重力区熔生长研究进行了分析.

Space Growth of Bismuth Telluride Based Thermoelectric Semiconductive Crystals

Bismuth telluride based thermoelectric semiconductors are high performance thermoelectric materials in the low temperature range (about 300℃), which have important applications in thermoelectric cooling and precise temperature control of electronic devices, and have broad application prospects in thermoelectric generation through industrial waste heat recovery. Bismuth tellurides are mainly produced with zone melting method, and their ZT value is around 0.8. The ZT value needs to be further improved as bismuth telluride is applied to commercial domain. Although alloying and doping are effective methods to improve the ZT value, they will make the chemical composition of bismuth tellurides become more complicated. The inherent problems of zone melting method, buoyancy force convection and wall effect, are revealed under gravity, and will make the fluctuation of chemical composition and thermoelectric properties become larger. Microgravity in space may eliminate the buoyancy force convection and wall effect, and can improve the chemical homogeneity and thermoelectric properties of bismuth tellurides. In this paper the development of zone melting of bismuth tellurides under microgravity is reviewed, and the following researched on the zone melting of bismuth telluride that will be carried on the Shijian-10 satellite and the Tiangong-2 space station is prospected.