能源是目前全球共同關注之焦點。開發各種替代能源、提高能源使用效率，都是非常重要之能源發展方向。熱電材料可以回收廢熱轉換成電能，提昇能源之使用效率，因此受到很大之重視。N型-(Bi2Se3)x(Bi2Te3)1-x為具有良好熱電性質之材料。先前研究結果更顯示，於N型-(Bi2Se3)x(Bi2Te3)1-x合金中摻雜第四元的Ga元素，能使熱電性質得到更進一步的提升。相圖是基本之材料資訊，對於材料製程的選擇、以及材料現象之瞭解，皆十分重要。然而目前文獻中並無Bi-Se-Te-Ga四元材料系統之相圖，本研究目的在於建構Bi-Se-Te-Ga四元系統相圖，以做為此熱電材料之開發與探討之基礎。本研究的工作包括：(1) 依據目前的文獻，建構Bi-Se-Te-Ga的三元子系統Bi-Se-Ga、Bi-Te-Ga、Ga-Se-Te及Bi-Se-Te於200oC之三元等溫橫截面圖；(2)以實驗的方法探討Bi含量40at.%之Bi-Se-Te-Ga在200oC及250oC下的等溫橫截面圖；(3)利用實驗的方法，探討與建構Bi-Se-Te及Bi-Se-Ga三元熱電系統之液相線投影圖。本研究已利用相關文獻建構出Bi-Se-Ga、Bi-Te-Ga、Ga-Se-Te及Bi-Se-Te於200oC下可能之等溫橫截面圖。在四元系統相圖的部分，建構出 Bi含量40at.%-Se-Te-Ga於200oC相圖兩個四相區的部分，屬於Ga含量較高的部分，包含Bi+Liquid+GaSe+GaTe以及Bi+Bi2Te+GaSe+GaTe兩個四相區。在Bi-Se-Te液相線投影圖的部分，建構出兩個首要析出相區包含Bi2(Se,Te)3及(Se,Te)，而在上半部則由於Bi-Te及Bi-Se相關二元相太過複雜而無法確認，其中沒有三元相的存在；在Bi2(Se,Te)3及(Se,Te)兩個相區的邊界上存在一個鞍點。在Bi-Se-Ga液相線投影圖的部分，包含Bi、Ga、GaSe、α- Ga2Se3、β-Ga2Se3、Se、Bi2Se3及未知的Bi-Se二元相等首要析出相區。於此三元系統中包含一Class III反應Liquid+Bi+GaSe=Ga，反應溫度為222oC；及一個Class II反應，Liquid+β-Ga2Se3=Bi+GaSe，反應溫度為260oC。

Energy-related issues are the world-wide focus nowadays. Thermoelectric
materials have attracted tremendous research interests because of their abilities
to convert waste heat directly into electricity and thus increase the energy usage
efficiencies. N-type-(Bi2Se3)x(Bi2Te3)1-x alloys have good thermoelectric
properties, and recent studies indicate their properties can be further enhanced
with Ga doping. Phase diagrams are basic materials information, and are
fundamentally important for the processing routes selection and understanding
of related phenomena. This study determines the phase diagrams of the Bi-Se-
Te-Ga system since there are only limited information available. The research
efforts of this study include: (1) determination the isothermal sections at 200oC,
based on the available related literatures, of the four constituent ternary systems
of the Bi-Se-Te-Ga system, Bi-Se-Ga、Bi-Te-Ga、Ga-Se-Te and Bi-Se-Te, (2)
experimental determination the 200oC isothermal sections of Bi-Se-Te-Ga at
composition at 40 at.% Bi, (3) experimental determination the liquidus
projections of Bi-Se-Te and Bi-Se-Ga systems. The item (1) has been completed,
and the Bi-Se-Ga、Bi-Te-Ga、Ga-Se-Te and Bi-Se-Te at 200oC isothermal
sections have been determined. Two four-phase regions, Bi+Liquid+GaSe+GaTe
and Bi+Bi2Te+GaSe+GaTe, are determined in the 200oC isothermal section of
Bi-Se-Te-Ga quaternary system at the Ga-rich corner. Since most of the binary
compounds at the Bi-rich side are not clearly determined, only the phase
relationships at the Se-Te side are determined. Two primary solidification phase
regions, Bi2(Se,Te)3 and (Se,Te), were confirmed. No ternary compound has been
found. There is a saddle point at the boundary of Bi2(Se,Te)3/(Se,Te). In the part
of Bi-Se-Ga liquidus projection, there are eight primary solidification phase
regions: Bi, Ga, GaSe, α-Ga2Se3, β-Ga2Se3, Se, Bi2Se3 and unknown Bi-Se
binary compounds. There are one class III reaction: Liquid+Bi+GaSe=Ga at
222oC and one class II reaction: Liquid+β-Ga2Se3=Bi+GaSe at 260oC.

六、參考文獻
1. 李進興、林廣遠、袁良彥、劉嘉東，新新季刊，第40期，127-134頁，(2012).
2. 黃振東、徐振庭，科學發展，第486期，48-53頁，(2013).
3. M. S. El-Genk, H. H. Saber and T. Caillat, Energy Conversion and Management, Vol. 44, pp. 1755-1772, (2003).
4. T. M. Tritt and M. A. Subramanian, Thermoelectric materials, phenomena, and applications: A bird's eye view. MRS Bulletin, Vol. 31, pp. 188-194, (2006).
5. H. S. Kim and S. J. Hong, Journal of Alloys and Compounds, Vol. 586, pp. S428-S431, (2014).
6. M. H. Bhuiyan, Y. Isoda, T. S. Kim and S. J. Hong, Intermetallics, Vol. 34, pp. 49-55, (2013).
7. Y. Du, K. F. Cai, H. Li and B. J. An, Journal of Electronic Materials, Vol. 40, No. 5, pp. 518-522, (2011).
8. M. H. Bhuiyan, T. S. Kim, J. M. Koo and S. J. Hong, Journal of Alloys and Compounds, Vol. 509, No. 5, pp. 1722-1728, (2011).
9. M. Allahkarami, L. S. Faraji, G. Kavei and Y. Zare, Materials Chemistry and Physics, Vol. 119, No. 1-2, pp. 145-148, (2010).
10. L. D. Ivanova, L. I. Petrova, Y. V. Granatkina, V. S. Zemskov, O. B. Sokolov, S. Y. Skipidarov and N. I. Duvankov, Inorganic Materials, Vol. 45, No. 2, pp. 123-128, (2009).
11. S. J. Hong, K. S. Hwang, J. W. Byeon, M. K. Lee, C. K. Rhee and B. S. Chun, Solid State Phenomena, Vol. 119, pp. 271-274, (2007).
12. N. P. Gorbachuk, V. V. Zakharov, V. R. Sidorko and L. V. Goncharuk, Powder Metallurgy and Metal Ceramics, Vol. 44, No. 7-8, pp. 372-376, (2005).
13. S. J. Hong and B. S. Chun, Materials Science and Engineering A-Structural Materials Properties Microstructure and Processing, Vol. 356, No. 1-2, pp. 345-351, (2003).
14. S. J. Hong, S. H. Lee and B. S. Chun, Materials Science and Engineering B- Solid State Materials for Advanced Technology, Vol. 98, No. 3, pp. 232-238, (2003).
15. S. J. Hong and B. S. Chun, Materials Research Bulletin, Vol. 38, No. 4, pp. 599-608, (2003).
16. O. B. Sokolov, S. Y Skipidarov, N. I. Duvankov and G. G. Shabunina, XXI International Conference on Thermolectrics, Proceedings Ict '02, pp. 1-4, (2002).
17. J. Navratil, P. Lostak and J. Horak, Crystal Research and Technology, Vol. 26, No. 6, pp. 675-681, (1991).
18. J. H. Yim, K. Jung, M. J. Yoo, H. H. Park, J. S. Kim and C. Park, Current Applied Physics, Vol. 11, No. 4, pp. s46-s49, (2011).
19. P. Lošťák, L. Beneš, S. Civiš and H. Süssmann, Journal of Materials Science, Vol. 25, No. 1, pp. 277-282, (1990).
20. T. Caillat, A. Borshchevsky and J.P. Fleurial, Journal of Applied Physics, Vol. 80, pp. 4442-4449, (1996).
21. A. J. Zhou, X. B. Zhao, T. J. Zhu, S. H. Yang, T. Dasgupt, C. Stiewec, R. Hassdorf and E. Mueller, Materials Chemistry and Physics, Vol. 124, pp. 1001-1005, (2010).
22. H. G. Bouanani, D. Eddike, B. Liautard and G. Brun, Materials Research Bulletin, Vol. 31, pp. 177-187, (1996).
23. V. F. Bankina and N. K. Abrikosov, Journal of Inorganic Chemistry, Vol. 9, pp. 509-512, (1964).
24. J. P. McHugh and W. A. Tiller, Transactions of the metallurgical society of AIME, Vol. 215, pp. 651-655, (1959).
25. J. F. Dumas, G. Brun, B. Liautard, J. C. Tédenac and M. Maurin, Thermochimica Acta, Vol. 122, pp. 135-141, (1987).
26. M. G. Shakhbazov, N. A. Seidova and P. G. Rustamov, Russian Journal of Inorganic Chemistry, Vol. 22, No. 9, pp. 1377-1381, (1977).
27. N. K. Abrikosov, V. F. Bankina and K. F. Kharitonovich, Russian Journal of Inorganic Chemistry, Vol. 5, pp. 978-982, (1960).
28. A. A. Sher, I. P. Odin and A. V. Novoselova, Russian Journal of Inorganic Chemistry, Vol. 31, pp. 435-437, (1986).
29. H. Okamoto, Binary Alloy Phase Diagrams, 2nd edition, Vol. 1, pp. 790-792, (1990).
30. F. Körber and U. Haschimoto, Zeitschrift für anorganische und allgemeine Chemie, Vol. 188, pp. 114-126, (1930).
31. N. Kh. Abrikosov and V. F. Bankina, Journal of Inorganic Chemistry, Vol. 3, No.3, pp. 152-165, (1958).
32. H. Okamoto and L. E. Tanner, Binary Alloy Phase Diagrams, 2nd edition, Vol. 1, pp. 800-801, (1990).
33. B. Predel, Zeitschrift fur Physikalische Chemie, Vol. 24, pp. 206-216, (1960).
34. S. P. Yatsenko and V. N. Danilm, Inorganic Materials, Vol. 4, pp. 758-762, (1968).
35. H. Okamoto, Binary Alloy Phase Diagrams, 2nd edition, Vol. 1, pp. 738-739, (1990).
36. P. Franke and D. Neuschütz, Landolt-Börnstein-Group IV Physical Chemistry, Vol. 19B2, pp. 1-3, (2004).
37. G. Ghosh, R. C. Sharma, D. T. Li and Y. A. Chang, Journal of Phase Equilibria, Vol. 15 No. 2, pp. 213-224, (1994).
38. H. Okamoto, Binary Alloy Phase Diagrams, 2nd edition, Vol. 2, pp. 1852-1854, (1990).
39. H. Suzuki and R. Mori, Japanese Journal of Applied Physics, Vol. 13, pp. 417-423, (1974).
40. J. C. Mikkelsen, Journal of Solid State Chemistry, Vol. 40, pp. 312-317, (1983).
41. U. R. Kattner, Binary Alloy Phase Diagrams, 2nd edition, Vol. 2, pp. 1864-1865, (1990).
42. R. Eholié and J. Flahaut, Bulletin de la Societe chimique de France, No. 4, pp. 1250-1254, (1972).
43. P. G. Rustamov and N. A. Seidova, Azerbaidzhanskii Khimicheskii Zhurnal, pp. 77-80, (1968).
44. P. G. Rustamov, N. A. Seidova and M. G. Shakhbazov, Russian Journal of Inorganic Chemistry, Vol. 21, No. 9, pp. 412-415, (1976).
45. K. Dobletov, N. K. Samakhotina, A. V. Anikin and A. Ashirov, Inorganic Materials, Vol. 11, pp. 1036-1038, (1975).
46. W. W. Jr. Warren, G. F. Brennert, E. Buehler and J. H. Wernick, Journal of Physics and Chemistry of Solids, Vol. 35, pp. 1153-1157, (1974).
47. M. G. Safarov, Azerbaidzhanskii Khimicheskii Zhurnal, pp. 127-132, (1970).
48. I. A. Aliev, Russian Journal of Inorganic chemistry, Vol. 53, pp. 1795-1800, (2008).
49. P. G. Rustamov and V. B. Cherstvova, Azerbaidzhanskii Khimicheskii Zhurnal, pp. 98-107, (1967).
50. N. K. Abrikosov and L. V. Poretskaya, Inorganic Materials, Vol. 23, pp. 1606-1608, (1987).