本研究以直接淬火法與時效熱處理法製備出(PbTe)1-x/(HgTe)x三元複合物，其中x分別為0.01、0.03、0.05以及0.07。使用X-ray粉末繞射(XRD)、光學顯微鏡(OM)、場發掃描式電子顯微鏡(FE-SEM)來分析各個複合物的成分組成與其微結構。熱電性值量測範圍包含電阻率、Seebeck係數以及熱傳導率，量測溫度範圍在50~300K之間，並計算其熱電優質ZT。

在顯微結構分析中發現，成分x=0.01, 0.03與0.05的樣品，在搖擺過程中，高熔點的PbTe事先析出，阻礙石英管內部的混合，導致此三種成分的下中上三段均無法搖擺均勻。在提高HgTe成分來降低熔點，以及提高搖擺溫度後，此現象得以改善，得到分散均勻的析出物。並藉由380°C的時效熱處理1、6、48小時，觀察到更多過飽和析出物的出現。

由熱電量測的分析結果，得知所有成分的樣品電阻率皆隨溫度上升而下降，為半導體特性，且Seebeck係數為正值，指出此材料為p-type半導體，也發現到經由時效熱處理的樣品，其Seebeck係數在室溫時比原型高出兩倍。熱傳導率因x=0.01, 0.03與0.05的樣品有較多析出物，造成較多聲子散射，導致熱傳導率比x=0.07小，但經由時效處理後，析出物的增加也些微的降低熱傳導率。

量測結果顯示，雖然時效的樣品有著Seebeck係數高和熱傳導率低的優點，但由於其電阻率過大，以致於ZT值不盡理想。x=0.01和0.03兩種成分的樣品，因擁有比較小的電阻率，在300K時可以得到最大的ZT值為0.14左右。

In this study, (PbTe)1-x/(HgTe)x (x=0.01, 0.03, 0.05, 0.07) composites were synthesized by direct quench and aging treatment. The composition and microstructure of these composites were analyzed by X-ray powder diffraction, optical microscope, scanning electron microscope. The thermoelectric properties of all samples were studied by means of thermal and electrical transport measurement in the temperature ranges 50 K to 300 K. Temperature dependence of resistivity, Seebeck coefficient and thermal conductivity of these samples were discussed.

From the microstructure analysis, revealed that samples of the first three compositions, do not mix very well. The XRD pattern of x=0.01 top part showed many small peaks in low angle. And the FESEM results indicated that the shape and dispersion of precipitates are different in three parts of samples. We presumed that PbTe, high melting point started to precipitate during the melting and shaking process. This phenomenon can be solved by increasing x composition to 0.07 to decrease the melting point and using higher temperature 900°C to melt. It came out that we got homogeneous dispersion of precipitates. And after the aging treatment process, many new from precipitates can be observed.

The resistivity decreases with increasing temperature for all samples, showing semiconducting properties. The Seebeck coefficient of all composites is positive, indicating these samples are p-type, and the biggest value is +450μV/K from the aging 6hr sample. Thermal conductivity increases with x increase and decreases with aging time due to form more grain boundaries.

The maximum figure of merit ZT was obtained as 0.14 in both samples x=0.01 and 0.03 at 300K because of lowest resistivity.

第一章 前言 1
第二章 基礎倫理與文獻回顧 7
第三章 實驗方法與步驟 23
第四章 實驗結果與討論 34
第五章 結論 84

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