Bi2Te3化合物是室溫下性質最突出的熱電材料，為具有凡得瓦爾鍵的層狀結構。本實驗分別將FeTe2及In2Te3兩種化合物，添加在Bi2Te3化合物中，欲觀察FeTe2及In2Te3分相的微結構，以及它們對熱電性質的影響。實驗結果顯示，固化時FeTe2在Bi2Te3中呈長條狀析出，長條析出物的間距約一微米。經過計算，發現析出相本身對Bi2Te3母相散射機制的影響微小，反而是少量的溶解在Bi2Te3晶體中的Fe元素，會造成載子濃度的變化，影響材料的熱電性質。整體而言，FeTe2的加入使Bi2Te3化合物的電阻率上升， Seebeck係數卻沒有提升，最大功率因子只有1.2*10-3 W/m-K2，表現比不上一般Bi2Te3系列合金材料。而添加In2Te3方面，參考相圖資料，Bi2-xInxTe3合金所配製的成分是落在靠近Bi2Te3側的固溶區內，經過適當的退火處理，可使In2Te3進行固態的析出反應。然而實驗結果卻發現，經過各種溫度退火處理，大部分的In元素仍固溶在Bi2Te3晶體中無法析出。固溶在晶體中的In元素導致Bi2Te3導電載子由p型轉為n型，Seebeck係數及電導皆下降。

Bi2Te3 is the most outstanding thermoelectric material near room temperature region. It has a laminar crystal structure with van der waals bonding in it. In this study, FeTe2 and In2Te3 were alloyed with Bi2Te3 respectively to investigate their microstructures and thermoelectric properties. For the FeTe2-Bi2Te3 system, the strip-like FeTe2 phase was found to segregate upon solidification and apart from each other by 1 □m approximately. According to theoretical calculation, it is found that the segregations have little influence on the scattering mechanism of charge carriers. Instead, Fe atoms which dissolved in Bi2Te3 lattice may change the carrier concentrations and thermoelectric properties of the alloys. The Seebeck coefficient and electrical resistivity of Bi2Te3 will decrease with the addition of FeTe2, leading to a lower power factor. For In2Te3-Bi2Te3 system, most of the indium atoms are still dissolved in Bi2Te3 crystal lattice which is not consistent with the equilibrium phase diagram published. The dissolution of indium results in the decrease in Seebeck coefficient and electrical conductivity of the alloys. The hole conduction is also found to change into electron conduction at a very high level of indium addition.

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