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.

總目錄
學位考試合格證明文件 i
誌 謝 ii
摘要 iv
ABSTRACT v
總目錄 vi
圖目錄 viii
表目錄 xi
第一章、緒 論 1
1.1熱電材料發展歷程 1
1.2 熱電材料簡介 2
1.3 熱電元件轉換原理 2
1.4 熱電模組應用 4
1.4.1 第一類是 TEG 屬於熱電發電 4
1.4.2 第二類是TEC 屬於熱電致冷 4
1.4.3 第三類是 Senser 應用 4
1.5 熱電效應及性質 4
1.5.1 Seebeck effect 5
1.5.2 Peltier effect 6
1.5.3 Thomson effect 7
1.5.4 熱電優質ZT ( Figure of Merit, FOM ) 8
1.6 熱電元件及材料類型 9
1.6.1 低溫型熱電材料 10
1.6.2 中高溫型熱電材料 10
1.6.3 高溫型熱電材料 10
1.7 熱電材料製備方法 10
1.8 碲-鉍及其合金 12
1.8.1 Bi2Te3 熱電材料 12
1.8.2 Bi0.5Sb1.5Te3熱電材料 13
第二章、文獻回顧與研究目的 30
2.1 文獻回顧 30
2.2 研究目的 33
第三章、實驗原理與方法 35
3.1 樣品製備 35
3.2 分析設備原理及實驗方法 35
3.2.1 X光繞射分析儀 35
3.2.2 感應耦合電漿發射分光分析儀 40
3.2.3 熱電性質量測 42
3.2.4 金相顯微組織觀察 42
3.2.5 掃描式電子顯微技術 43
3.2.6 X光能量散佈光譜技術 44
3.2.7 穿透式電子顯微鏡 44
第四章、結果與討論 53
4.1 X光繞射及晶體結構分析 53
4.2 熱電性質分析 54
4.3 熱電材料配比ICP-OES定量分析 60
4.4 Rietveld 晶體結構分析 61
4.5 金相顯微組織觀察 ( Optical Microscope, OM ) 62
4.6 SEM表面分析與EDS成份分析 63
4.7 TEM 晶體結構分析 64
第五章、總結 86
第六章、未來工作 88
參考文獻 89

[1] 熱電材料與元件之發展與應用，朱旭山。工業材料，第220期。
[2] 熱電元件於電子及光電封裝熱管理之應用，劉君愷。工業材料，第285期。
[3] 熱電材料與元件之原理與應用，朱旭山。電子與材料 第22期。
[4] T. J. Seebeck, “Magnetic Polrization der Metalle und Erze durch Temperature-Differenze. Abhand deut,” Akad. Wiss. Berlin, 1822, pp. 289-346.
[5] J. C. Peltier, “Nouvelles experiences sur la caloricite des courants electriques,” Ann. Chim. Phys, 1834, pp. 371-386.
[6] W. Thomson, “On a Mechanical Theory of Thermoelectric Currents,” Proceedings of the Royal Society of Edinburgh, 1851, pp. 91-98.
[7] D. R. Rowe, “Thermoelectric Handbook : Micro to Nano,” CRC press, 2006.
[8] S. Chen, Z. Ren, “Recent Progress of Half-Heusler for Moderate Temperature thermoelectric applications,” Materials Todays, 2013,16, pp. 387-395.
[9] G. P. William, “Zone Melting,” 2nd edition, 1966.
[10] H. J. Noh, “Spin-Prbit interaction effect in the electronic structure of Bi2Te3 Observed by angle-Resolved Photoemission Spectroscopy,” 2008, pp. 57006-p1.
[11] E. Koukharenko, N. Frety, “Electrical properties of Bi2-xSbxTe3 materials obtained by ultrarapid quenching.” Journal of Alloys and Compounds, 2001, pp. 1-4.
[12] S. Michel, S. Diliberto, N. Stein, B. Bolle, C. Boulanger, “Characterisation of electroplated Bi2(Te1-xSe)3 alloys,” J. Solid State Electro. Chem, 2008, pp. 95.
[13] Z. J. Xu, “Enhanced thermoelectric and mechanical properties of zone melted p-type (Bi, Sb)2Te3 thermoelectric materials by hot deformation,” Acta Materialia, 2015, pp. 385-392.
[14] D. M. Rowe, “Thermoelectric Handbook Macro to Nano,” 2006.
[15] R.P. Chasmar, R. Stratton, “The thermoelectric figure of merit and its relation to thermoelectric generators.” J Electron Control, 1959, pp. 52-72.
[16] A. Bulusu, D.G. Walker, “Review of electronic transport models for thermoelectric materials,”. Superlat Microstruct, 2008, pp. 1-36.
[17] H. J. Goldsmith, “Introduction to thermoelectricity,” Heidelberg: Springer, 2010.
[18] G. D. Mahan, M. Bartkowiak, “Wiedemann-Franz Law at Boundaries,” Applied Physics Letters, 1999, pp. 953-954.
[19] E. Koukharenko, “Electrical properties of Bi2-xSbxTe3 materials obtained by ultrarapid quenching,” Journal of Alloys and Compounds, 2001, pp. 1-4.
[20] L. Xue-Dong, “Structure and Transport Properties of (Bi1-xSbx)2Te3 Thermoelectric Materials Prepared by Mechanical Alloying and Pulse Discharge Sintering Materials Transactions,” 2002, pp. 681-687.
[21] T. H. Liang, S. Q. Yang, Z. Chen, Q. X. Yang, “High Thermoelectric Performance of P-type Bi0.5Sb1.5Te3+xTe Crystals Prepared via Gradient Freezing,” Advanced Materials Research, 2013, pp. 167-171.
[22] G. KAVEI, “(Bi2Te3)0.25(Sb2Te3)0.75 crystal structure improvements with excess Te as studied by AFM, SEM, EBSD and XRD,” Materials Science-Poland, 2011, pp. 143-151.
[23] H. Ryu, H. MI-KYUNG, K. SUNG. JIN, “Effect of Chromium Doping on the Thermoelectric Properties of Bi2Te3: CrxBi2Te3 and CrxBi2-xTe3,” Journal of Electronic Materials, 2013, pp. 2758-2763.
[24] J. Jiang, L. Chen, S. Q. Bai, “Thermoelectric properties of p-type (Bi2Te3)x(Sb2Te3)1-x crystals prepared via zone melting,” Crystal Growth, 2005, pp. 258-263.
[25] H.M. Rietveld, “A profile refinement method for nuclear and magnetic structures.” Journal of Applied Crystallography, 1969, pp. 65-71.