熱電材料可利用「摻雜」方式，改變材料微結構，來達到提高熱電材料之ZT值。本研究利用區熔法(Zone melting)來製備具有組織取向且純度高的p型Bi0.5Sb1.5Te3熱電材料，並藉由摻雜不同碲(Te)含量，0、2.5、3.0、3.5和4.0 wt. %，作為研究比例。在物理特性研究分析結果發現p-type熱電材料之晶格常數在額外添加碲(Te)含量為3.0 wt. %時有最大值，且c軸為a軸的7倍說明晶體結構是以沿c軸方向來成長，具有異向性。在熱電性質表現上，最佳成份為Bi0.5Sb1.5Te3+ 3.0 wt.% 碲(Te)，在340K時有最佳ZT值為1.15。在微結構及成份分析結果中，發現當Te添加量增加至3.0 wt. %時，在其微結構上形成兩相組織，藉由TEM研究結果確認其為純Te析出之偏析相。研究結果表明: 額外添加碲(Te)含量有助於熱電性質提升，但「過量」則會導致於過多偏析相析出，使電導率及總熱傳導係數降低，進而影響熱電性質整體的表現。

Thermoelectric materials can be used "doping" approach to change the microstructure, and improve the ZT value. In this study, the zone melted p-type Bi0.5Sb1.5Te3 thermoelectric materials with high orientation and texture were prepared with by doping different Te content, 0, 2.5, 3.0, 3.5 and 4.0 wt. %, respectively. The lattice constant maximum of the p-type thermoelectric materials is was located at 3.0 wt. % Te, and the c axis is 7 times as much as the a-axis, because the direction of crystal growth with anisotropy in the c-axis direction. In the thermoelectric properties, the optimum ZT value is 1.15 at 340 K. The results of microstructure and composition analysis, show the excess Te-doped was increased to 3.5 wt. % with the two-phase structure on the microstructure. The segregation phase was confirmed by TEM was pure Te, while the addition of appropriate amount of tellurium (Te) contributes to the improvement of the thermoelectric properties. However the "excess" leads to excessive segregation, which decreases the electrical conductivity and the thermal conductivity.

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