本研究是以高溫熔融搖擺搭配直接淬火(Direct Quench)的方式製備出碲化鉛，再加入不同比例之石墨烯後利用冷壓製程合成(Graphene/PbTe)複合物，摻入石墨烯的比例為0、0.1、1、3、5、10wt%，後使用X-ray繞射(XRD)、光學顯微鏡(OM)、場發式掃描式電子顯微鏡(FE-SEM)來分析其成份組成及顯微結構。熱電性質量測包含電阻率、Seebeck係數和熱傳導率隨溫度變化，量測溫度範圍在60～300 K，並利用上述的數據計算其熱電優值ZT。
摻入石墨烯之PbTe複合物在電阻率方面呈現半導體特性，且隨著石墨烯成分增加而減少，最低之電阻率為加入10wt%樣品的0.006ohm-cm；在Seebeck係數方面量所有加入石墨烯的樣品皆為p-type，其中，石墨烯比例0.1wt%的樣品有最佳的Seebeck係數達到306 μV/K；在熱傳導率方面所有樣品皆隨溫度上升而下降；由上述熱電性質計算過後，最佳的熱電優值為加入石墨烯0.1wt%的樣品，歸因於其具有較高的Seebeck係數及較低的熱導率，在300 K時有最高的ZT值達到0.03。
摻入石墨烯樣品的ZT值與未摻雜的樣品相比並未得到改善，這是因為其seebeck係數及熱導率方面表現不佳，儘管加入石墨烯後電阻率有明顯改善，但仍無法抵銷seebeck係數及熱導率所造成的影響。
關鍵字：熱電材料、直接淬火、粉末冶金、石墨烯、熱電優值

In this study, Graphene/PbTe composites with various Graphene composition 0、0.1、1、3、5 and 10wt% were prepared by cold pressing and annealing. The composition and microstructure of these composites were examined by optical microscope(OM), X-ray diffraction(XRD), field emission scanning electron microscope(FE-SEM) and energy dispersive X-ray spectroscopy(EDS). The thermoelectric properties for these composites were studied by means of thermal and electrical transport measurement in the temperature range between 60 K and 300 K. The temperature dependence of the thermoelectric properties of Graphene/PbTe composites were discussed.
The electrical resistivity of Graphene/PbTe composites are decreased with increasing temperature showing semiconducting properties. And the electrical resistivity also decreased with increasing Graphene content. The lowest value of resistivity is 0.006ohm-cm for the PbTe sample with 10wt% Graphene at 300K . The seebeck coefficient of all the Graphene/PbTe composites are positive , showing p-type conduct and the highest seebeck coefficient(306uV/K) are obtained at 300K for Graphene/PbTe composites with 0.1wt% Graphene . The thermal conductivity of these composites decreased with increasing temperature. The Graphene/PbTe composite with 0.1wt Graphene exhibits the maximum ZT=0.03 at 300 K which was attributed to its highest seebeck coefficient and lowest thermal conductivity.
The thermoelectric properties of Graphene/PbTe composites were not enhanced due to their low Seebeck coefficient and high thermal conductivity, although the resistivity was significantly improved after the addition of graphene.

目錄 1
圖目錄 3
表目錄 5
第一章 緒論 6
1-1前言 6
1-2研究動機 8
第二章 理論基礎與文獻回顧 10
2-1 材料基本特性 10
2-1-1 PbTe基本特性 10
2-1-2石墨烯 基本特性 11
2-2 熱電理論 12
2-2-1 Seebeck效應 12
2-2-2 Peltier效應 13
2-2-3 Thomson效應 14
2-3 熱電材料物理性質 15
2-3-1 電阻率 15
2-3-2 Seebeck係數 16
2-3-3 熱傳導現象 18
2-3-3-1 電子對熱傳導的影響 19
2-3-3-2 聲子對熱傳導的影響 19
第三章 實驗方法與步驟 23
3-1 實驗方法 23
3-2 實驗步驟 27
3-2-1 石英管之前處理 27
3-2-2 元素秤重及封管 28
3-2-3 高溫搖擺即直接淬火 30
3-2-4 冷壓退火 32
3-3 樣品製備與量測 34
3-3-1 電阻率樣品製備與量測 34
3-3-2 熱傳導率與Seebeck係數樣品製作及量測 35
3-3-3 熱電量測系統及控制程式 36
3-4 顯微結構與成分分析 39
3-4-1 XRD(X-ray diffractometer) 39
3-4-2 場發射型掃描式電子顯微鏡(FE-SEM) 39
第四章 實驗結果與討論 40
4-1 顯微結構與成分分析 41
4-1-1 XRD分析 41
4-1-2 光學顯微鏡分析 43
4-3-3 場發射掃描電子顯微鏡分析 53
4-2 熱電性質量測分析 65
4-2-1 電阻率 65
4-2-2 Seebeck係數 67
4-2-3 熱傳導率 68
4-2-4 熱電優值ZT 69
第五章 結論 71
參考文獻 73

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