現代科技發展日漸進步，能源需求及消耗漸增，在全球面臨著能源耗竭的危機之下，為使能源使用達最大效率，開發新的能源來源、或者減少能源浪費是必要的。熱電材料可以將熱與電兩種能源直接轉換，中間不需要任何機械轉換，其特點是可將廢熱回收轉換成電能進行二次能源使用，期能對能源議題帶來助益。三元Ag-Ga-Te為極具潛力的熱電材料系統，其中又以p型三元相AgGaTe2受注目，其為黃銅礦結構(chalcopytire)，熱電優值(figure-of-merit)峰值約落在600-800oC，且熱傳導係數低，κ=0.2Wm-1K-1，使其zT值可達到1.2。相圖是材料發展的基礎資料之一，在研究各種材料性質的時候，可以利用相圖研究，探討其相變化、相生成極為結構變化，而取得材料的基本資訊，由於現有文獻中少有三元系統Ag-Ga-Te的相圖，本研究目的即是以實驗方式建構Ag-Ga-Te三元系統相圖，做為往後熱電性質研究之依據，再依據相圖選定特別組成之成分合金，量測其熱電性質。本研究包括：(1)以實驗建構Ag-Ga-Te於650oC的等溫橫截面相圖；(2)以實驗測定Ag-Ga-Te三元系統的液相線投影圖；(3)選定特定組成之合金，對其進行熱電性質的量測。本實驗確認AgGaTe2及Ag9Ga1Te6在650oC下之相穩定區，且看出其具有溶解度，AgGaTe2固溶度由22.7at.%Ag-28.6at.%Ag或50.0at.%Te-52.0at.%Te；Ag9Ga1Te6固溶度由2.8at.%Ga-11.8at.%Ga或34.9at.%Te-39.4at.%Te，並在液相線投影圖中以實驗確立Ag、Ag5Te3、Ag2Te、Ag1.9Te、Te、Ga2Te5、Ga2Te3、GaTe、Ag2Ga3、Ag2Ga、Ag3Ga及三元相AgGaTe2之¬首要析出相區，及液相相分離區的延伸情形，左側液相相分離區由Ag2Te、AgGaTe2及Ag2Ga切割。

Thermoelectricity converts waste heat into electricity directly and reversibly. Ag-Ga-Te ternary system is a promising thermoelectric system, mainly due to the p-type chalcopyrite AgGaTe2. The peak zT(figure-of-merit) value of AgGaTe2 is around 1.2 at the region of 600-800oC. Phase diagram provides materials’ fundamental information, and is important for understanding the phase relations and controlling the microstructures. However, for the Ag-Ga-Te system, only limited information is available. This study is keen to determine the phase relations of Ag-Ga-Te system at 650oC,including: (1) experimentally determine the isothermal section of Ag-Ga-Te system at 650oC by thermally annealing ternary Ag-Ga-Te alloys, (2) experimentally determine the liquidus projection of Ag-Ga-Te system by directly air-cooling or water-quenching ternary Ag-Ga-Te alloys (3) synthesize ternary Ag-Ga-Te alloys with specific composition and measure the thermoelectric properties such as Seebeck coefficient, electrical resistivity and thermal conductivity at elevated temperatures. The homogeneity region of the ternary compound AgGaTe2 at 650oC as well as its primary solidification region are mapped. Moreover, the liquidus projection of Ag-Ga-Te system contains two miscibility gaps that originated from its constituent Ag-Te and Ga-Te systems, and is found to be divided by primary solidification phases Ag2Te, AgGaTe2 and Ag2Ga.

摘要 i
Abstract ii
總目錄 iii
圖目錄 vi
表目錄 xvii
一、 前言 1
二、 文獻回顧 9
2.1 Ag-Ga二元子系統 9
2.2 Ga-Te二元子系統 10
2.3 Ag-Te二元子系統 11
2.4 Ag2Te-Ga2Te3 等值剖面圖 12
2.5 Ag-Ga-Te三元系統熱電性質 12
三、 實驗方法 17
3.1 合金製備 17
3.2 相平衡熱處理 17
3.3 金相分析 17
3.4 X光粉末繞射分析 18
3.5 微差熱分析 18
3.6 熱電性質分析 18
四、 結果與討論 20
4.1 液相線投影圖 20
4.1.1 Te首要析出相區 25
4.1.2 Ga2Te5首要析出相區 28
4.1.3 Ga2Te3首要析出相區 32
4.1.4 AgGaTe2首要析出相區 41
4.1.5 Ag5Te3首要析出相區 58
4.1.6 Ag2Te首要析出相區 66
4.1.7 Ag2Ga首要析出相區 89
4.1.8 GaTe及AgGaTe2首要析出相區之邊界 94
4.1.9 GaTe首要析出相區 96
4.1.10 DTA微差熱分析 113
4.1.11液相線投影圖結果 126
4.2 650oC等溫橫截面相圖 129
4.2.1 AgGaTe2-liquid兩相區 132
4.2.2 Ga2Te3-liquid兩相區 136
4.2.3 Ga2Te3 單相區 138
4.2.4 Ga2Te3-GaTe兩相區 140
4.2.5 Ga2Te3-AgGaTe2-GaTe三相區 144
4.2.6 AgGaTe2-GaTe兩相區 146
4.2.7 AgGaTe2 單相區 148
4.2.8 AgGaTe2- Ag9Ga1Te6-GaTe三相區 150
4.2.9 AgGaTe2-Ag9Ga1Te6-liquid三相區 154
4.2.10 Ag9Ga1Te6單相區 157
4.2.11 Ag2Te-Ag兩相區 159
4.2.12 Ag2Te-Ag-liquid三相區 162
4.2.13 Ag9Ga1Te6-GaTe-liquid三相區 165
4.2.14 GaTe-liquid兩相區 169
4.2.15 650oC等溫橫截面圖結果 178
4.3 AgGaTe2熱電性質 181
4.3.1 AgGaTe2 等比例組成合金之熱電性質 181
4.3.2 AgGaTe2 參雜Cu元素之熱電性質 186
五、 結論 190
六、 參考文獻 193

1. G. J. Snyder, and E. S. Toberer, Complex thermoelectric materials, Nature Materials, Vol. 7, pp. 105-114, (2008).
2. T.M.Tritt and M.A.Saber, Thermoelectric Materials, Phenomena, and Applications: A Bird’s Eye View, MRS Bulletin, Vol.31, pp. 188-194, (2006).
3. F.R. Yu, J.J. Zhang, D.L. Yu, J.L. He, Z.Y. Liu, Bo Xu, Y.J. Tian, Enhanced thermoelectric performance of AgSbTe2 synthesized by high pressure and high temperature, Journal of Applied Physics, Vol.104, pp. 094303–094305,(2009).
4. L.E. Bell, Cooling, heating, generating power, and recovering waste heat with thermoelectric systems, Science, Vol.321, pp. 1457-1461, (2008).
5. S. Bhattacharya, A. Bohra, R. Basu, R. Bhatt, S. Ahmad, K. N. Meshram, A. K. Debnath, A. Singh, S. K. Sarkar, M. Navneethan, Y. Hayakawa, D. K. Aswal and S. K. Gupta, High thermoelectric performance of (AgCrSe2)(0.5)(CuCrSe2)(0.5) nano-composites having all-scale natural hierarchical architectures, Journal of Materials Chemistry A, Vol.2, pp. 17122–17129,(2014).
6. J. Androulakis, K.F. Hsu, R. Pcionek, H. Kong, C. Uher, J.J. D’Angelo, A. Downey, T. Hogan, M.G. Kanatzidis, Nanostructuring and high thermoelectric efficiency in p-type Ag(Pb1-ySny)(m)SbTe2+m, Advanced Material, Vol.18, pp. 1170–1173. (2006)
7. B. Poudel, Q. Hao, Y. Ma, Y. Lan, A. Minnich, B. Yu, X. Yan, D. Wang, A. Muto, D. Vashaee, X. Chen, J. Liu, M.S. Dresselhaus, G. Chen, Z. Ren, High-thermoelectric performance of nanostructured bismuth antimony telluride bulk alloys, Science, Vol.320, pp. 634–638,(2008).
8. M.R. Marie, G. Brun, J.C. Tedenac, Phase equilibria in the Sb2Te3-Ag2Te system, Journal of Material Science, Vol. 20,No.2, pp.730–735, (1985).
9. S.H. Yang, T.J. Zhu, T. Sun, J. He, S.N. Zhang, X.B. Zhao, Thermoelectric Materials (GeTe)x(AgSbTe2)100-x, Nanotechnology, Vol. 19, pp. 245707–245711, (2008).
10. D. T. Morelli, V. Jovovic and J. P. Heremans, Intrinsically Minimal Thermal Conductivity in Cubic I-V-VI2 Semiconductors, The American Physical Society, Vol. 101, pp. 035901-1 - 035901-4, (2008)
11. J. DiSalvo, Thermoelectric Cooling and Power Generation, Science Vol.285, pp. 703-706,(1999)
12. G. Jeffrey Snyder, Small Thermoelectric Generators, The Electrochemical Society Interface, Vol. 17 No.3, pp.54-56, (2008)
13. W. Wu, K. Wu, Z. Ma, R. Sa, Doping and temperature dependence of thermoelectric properties of AgGaTe2:First principles investigations, Chemical Physics Letters, Vol.537, pp.62-64, (2012)
14. A.J. Minnich, M. S. Dresselhaus, Z. F. Ren and G. Chen, Bulk nanostructured thermoelectric materials: current research and future prospects Energy Environmental Science, Vol.2, pp. 466-479,(2009)
15. C.J. Vineis , A. Shakouri , A. Majumdar , and M. G. Kanatzidis, “Nanostructured Thermoelectrics: Big Efficiency Gains from Small Features”, Advanced Materials, Vol. 22, pp.3970–3980, (2010)
16. M. Zhao,J. Zhang, N. Y. Gao, P. Song, M. Bosman, B. Peng, B. Q. Sun, Actively Tunable Visible Surface Plasmons in Bi2Te3 and their Energy-Harvesting Applications, Advanced Materials, Vol.28, pp.3138-3144,(2016)
17. X. B. Zhao, X. H. Ji, Y. H. Zhang, T. J. Zhu, J. P. Tu, and X. B. Zhang, Bismuth telluride nanotubes and the effects on the thermoelectric properties of nanotube-containing nanocomposites, Applied Physics, Vol.86, pp.062111,(2005)
18. W. Xie, S. Wang, S. Zhu, J. He, T. M. Tritt and Q. Zhang, High performance Bi2Te3 nanocomposites prepared by single-element-melt-spinning spark-plasma sintering, The Journal of Materials Science, Vol.10, pp.1007,(2012)
19. R. Venkatasubramanian, E. Siivola, T. Colpitts and B. O’Quinn, Thin-film thermoelectric devices with high room-temperature figures of merit, Nature, Vol. 413, pp. 597-602, (2001)
20. M. A. Baghchesaraa , R. Yousefib, M. Cheraghizadec, F. Jamali-Sheinid, A. Saáedic, M.R. Mahmmoudiane, A simple method to fabricate an NIR detector by PbTe nanowires in a large scale, Materials Research Bulletin, Vol.77, pp.131-137,(2016)
21. Q. Zhang, E. K. Chere, Y. M. Wang, H. S. Kim, R. He, F. Cao, K. Dahal, D. Broido, G. Chen, Z. Ren, High thermoelectric performance of n-type PbTe1ySy due to deep lying states induced by indium doping and spinodal decomposition, Nano Energy, Vol.22, pp.572-582,(2016)
22. K. F. Hsu, S. Loo, F. Guo, W. Chen, J. S. Dyck, C. Uher, T. Hogan, E. K. Polychroniadis and M. G. Kanatzidis, Cubic AgPb(m)SbTe(2+m): bulk thermoelectric materials with high figure of merit, Science, Vol. 303, pp. 818-21, (2004)
23. X.Y. Yang, J.H. Wu, M. Gu, X.G. Xia, L.D. Chen, Fabrication and contact resistivity of W–Si3N4/TiB2–Si3N4/p–SiGe thermoelectric joints, Ceramics International, Vol.42, pp.8044-8050,(2016)
24. S. Bathula, M. Jayasimhadri, A. Dhar, Mechanical properties and microstructure of spark plasma sintered nanostructured p-type SiGe thermoelectric alloys, Materials and Design, Vol.87, pp.414-420, (2015)
25. A.J. Zhou, X.B. Zhao, T.J. Zhu, S.H. Yang, T. Dasgupt, C. Stiewec, R. Hassdorf and E. Mueller., Microstructure and thermoelectric properties of SiGe-added higher manganese silicides, Materials Chemistry and Physics, Vol. 124, pp. 1001-1005, (2010).
26. D. Parker and D. J. Singh, Thermoelectric properties of AgGaTe2 and related chalcopyrite structure materials, Physical Review B ,Vol. 85, pp.125209-1-125209-7, (2012)
27. T. Plirdpring , K. Kurosaki , A. Kosuga , T. Day , S. Firdosy ,V.r Ravi , G. J. Snyder , A. Harnwunggmoung , T. Sugahara , Y. Ohishi ,H. Muta , and S. Yamanaka, “Chalcopyrite CuGaTe2 : A High-Efficiency Bulk Thermoelectric Material”, Advanced Materials, Vol. 24, pp. 3622–3626, (2012)
28. L.-C. Xu, R.-Z. Wang, L.-M. Liu, Y.-P. Chen, X.-L. Wei, H. Yana, and W.-M. Lau, “Wurtzite-type CuInSe2 for high-performance solar cell absorber: ab initio exploration of the new phase structure”, Journal of Materials Chemistry, Vol. 22, pp. 21662, (2012)
29. A.Charoenphakdee, K. Kurosaki, H. Muta, M. Uno and S. Yamanaka, Thermal Conductivity of the Ternary Compounds:AgMTe2 and AgM5Te8 (M = Ga or In), Materials Transactions, Vol. 50, pp. 1603-1606, (2009)
30. A. Yusufu, K. Kurosaki, A. Kosuga, T Sugahara, Y. Ohishi, H. Muta, S. Yamanaka, Thermoelectric properties of Ag1-xGaTe2 with chalcopyrite structure, Applied Physics Letters, Vol.99, pp.061902-1-061092-3, (2011)
31. V. K. Gudelli, V. Kanchana, G. Vaitheeswaran, Svane, and N. E. Christensen, “Thermoelectric properties of chalcopyrite type CuGaTe2 and chalcostibite CuSbS2”, Journal of Applied Physics, Vol. 114(22), pp. 223707, (2013)
32. Y. Li, Q. Meng, Y. Deng, H. Zhou, Y. Gao, Y. Li, J. Yang, and J. Cui, “High thermoelectric performance of solid solutions CuGa1− x InxTe2 (x = 0–1.0)”, Journal of Applied Physics, Vol. 100(23), pp. 231903,(2012)
33. J. Cui, Y. Gao, H. Zhou, Y. Li, Q. Meng, and J. Yang, “Significantly enhanced thermoelectric figure of merit through Cu, Sb co-substitutions for Te in Ga2Te3”, Applied Physics Letters, Vol. 101, pp. 081908-1, (2012)
34. L. Xue, B. Xu, D. Zhao, L. Yi, “First-principle calculations of the electronic, elastic and thermoelectric properties of Ag doped CuGaTe2”, Intermetallics, Vol.55, pp. 204-209, (2014)
35. D. Zou, S. Xie, Y. Liu, J. Lin, J. Li, “First-principles study of thermoelectric and lattice vibrational properties of chalcopyrite CuGaTe2”, Journal of Alloys and Compounds, Vol.570, pp.150-155, (2013)
36. J. Zhang, X. Qin, D. Li, C. Song, X. Zhu, Y. Liu, H. Xin, L. Chen, T. Zou, “Enhanced thermoelectric performance of CuGaTe2 by Gd-doping and Te incorporation”, Intermetallics, Vol. 60, pp.45-49, (2015)
37. K. Biswas, J. He, I. D. Blum, C.I. Wu, T. P. Hogan, D. N. Seidman, V. P. Dravid & M. G. Kanatzidis, “High-performance bulk thermoelectrics with all-scale hierarchical architectures”, Nature, Vol. 489, pp. 414-418, (2012)
38. J. Yang, S. Chen, Z. Du, X. Liu, and J. Cui, Lattice defects and thermoelectric properties: the case of p-type CuInTe2 chalcopyrite on introduction of zinc, Dalton Transactions, Vol. 43, pp. 15228-15236, (2014)
39. Y. Zhang, J.K. Liang, J.B. Li, Q.L. Liu, Y.G. Xiao, Q. Zhang, B.J. Sun, and G.H. Rao, Phase relations of the Ag–Ga–N system, Journal of Alloys and Compounds, Vol.429, pp. 184-191, (2007)
40. D. Mouani, G. Morgant, and B. Legendre, Study of the phase equilibria in the ternary gold-gallium-tellurium system, Journal of Alloys and Compounds, Vol.226, p 222-231, (1995)
41. W. Gierlotka, Thermodynamic assessment of the Ag–Te binary system, Journal of Alloys and Compounds, Vol. 485, pp. 231-235, (2009)
42. A. Prince, VCH, Vol.2, pp. 159-163, (1988)
43. K. Aravinth, G.A. Babu , P.Ramasamy, Silver gallium telluride (AgGaTe2) single crystal: Synthesis, accelerated crucible rotation-Bridgman growth and characterization, Materials Science in Semiconductor Processing, Vol.24, pp.44-49, (2014)
44. S. Brandon, J.J. Derby, Heat transferrin vertical Bridgman growth of oxides: effects of conduction, convection, and internal radiation, Journal of Crystal Growth, Vol.121, pp.473-494, (1992)