熱電材料能提升能源的使用效率，將其搭配太陽能板使用時更能當作新的再生能源，因此吸引了大量的研究熱潮。Bi2(Sb,Te)3和Bi¬2(Se,Te)3是最常使用的熱電材料，據報導得知，它們的熱電性質可以藉由摻雜In來改善。它們通常被使用在熱電模組中的接點，且其含有In的合金也頻繁的被當作焊接劑使用。相圖能提供物質基礎的資訊，對物質的發展能有一定程度的了解。界面反應的知識對接點的評估十分重要。此論文分成兩個部分，第一個部分是Bi-In-Se液相線投影圖，第二個部分是In/Bi2Se3的界面反應。論文中相關的數據是之前文獻中所缺少的，其對Bi2(Sb,Te)3和Bi2(Se,Te)3為基底的熱電模組相當重要。Bi-In-Se液相線投影圖是以實驗得到的結果，除了Se區域外，此系統的首要析出相為Bi2Se3, In2Se3, In6Se7, InSe, In4Se3, In, , BiIn2, Bi3In5, BiIn, Bi, 和(Bi2)m(Bi2Se3)n¬相;不變反應包含了L=In2Se3+Bi2Se3+Se, L+In2Se3+InSe=In6Se7, L+Bi+InSe=In2Se3, L+In2Se3=(Bi2)m(Bi2Se3)n+Bi, L+In2Se3=Bi2Se3+(Bi2)m(Bi2Se3)n, L+InSe=Bi+BiIn, L+InSe=In4Se3+BiIn2, L+In4Se3+In=, L+InSe+BiIn=Bi3In5, L+InSe=Bi3In5+BiIn2 和 L=In4Se3+BiIn2+ 。此系統有三個鞍點與三個不互溶區間。第二個部分是In與Bi2(Se,Te)3熱電材料的界面反應，此界面反應分別是In/Bi2Te3反應偶在溫度140、200和400oC; In/Bi2Se3反應偶在溫度100、140、200、250和400oC; In/Bi2(Se,Te)3在溫度200和250oC。在反應溫度140oC In/(Sb,Bi)2Te3固固反應偶中發現三元的介金屬相，同時在反應時間90天，反應溫度140oC 的In/Bi2Se3反應偶中並沒有明顯的界面反應。在液固反應偶中皆有界面反應的發生，像是在反應溫度250oC的In/Bi2Se3反應偶中觀察到In4Se3、InSe、In2Se3和(Bi2)m(Bi2Se3)n相;反應溫度250oC的In/(Sb,Bi)2Te3反應偶中觀察到In4Te3、InTe和In3Te3-x(Sb,Bi)x相。以上觀察到的相皆使用掃描式電子顯微鏡與電子微探儀進行顯微圖與組成分析，此外相的晶體繞射與不變反應溫度使用X-ray粉末繞射分析與熱差分析進行檢測.

Thermoelectrics have attracted a lot of research interests primarily because of their potentials in enhancing the energy usage efficiency and as renewable energy sources when used together with solar heating panels. Bi2(Sb,Te)3 and Bi2(Se,Te)3 are the most commonly used thermoelectric materials. It has been reported that their thermoelectric properties could be improved with indium doping. There are usually numerous joints in thermoelectric modules. Indium-containing alloys are frequently used as solders. Phase diagrams provide fundamental information and are essential for materials understanding and development. Knowledge of interfacial reactions is critical for the reliability assessment of joints. This study has two parts. One part is the determination of phase diagram, Bi-In-Se liquidus projection, and the other part is interfacial reaction investigation of the In/Bi2Se3 interfacial reactions. The related data are previously lacking in the literature but are important for the development of the Bi2(Sb,Te)3 and Bi2(Se,Te)3-based thermoelectric modules. The experimental determinations of the Bi-In-Se liquidus projection reveal, except for Se regime, the primary solidification phases are Bi2Se3, In2Se3, In6Se7, InSe, In4Se3, In, , BiIn2, Bi3In5, BiIn, Bi, and (Bi2)m(Bi2Se3)n phases, respectively. The invariant reactions include L=In2Se3+Bi2Se3+Se, L+In2Se3+InSe=In6Se7, L+Bi+InSe=In2Se3, L+In2Se3=(Bi2)m(Bi2Se3)n+Bi, L+In2Se3=Bi2Se3+(Bi2)m(Bi2Se3)n, L+InSe=Bi+BiIn, L+InSe=In4Se3+BiIn2, L+In4Se3+In=, L+InSe+BiIn=Bi3In5, L+InSe=Bi3In5+BiIn2, and L=In4Se3+BiIn2+. There are three saddle points and three miscibility gaps in the system. The second part is the interfacial reactions between Indium and Bi2(Se,Te)3 thermoelectric materials. Those reacted couples are In/Bi2Te3 at 140, 200, 400oC, In/Bi2Se3 at 100, 140, 200, 250, 400oC, In/(Sb,Bi)2Te3 at 140, 200, 250oC, and In/Bi2(Se,Te)3 at 200, 250oC. Ternary intermetallic compound is found in the solid/solid couples In/(Sb,Bi)2Te3 reacted at 140oC meanwhile no significant interfacial reactions are found in In/Bi2Se3 couples reacted at 140oC for up to 90 days. Complex and significant interfacial reactions occur in all the liquid/solid. For example, In4Se3, InSe, In2Se3 and (Bi2)m(Bi2Se3)n phases in the In/Bi2Se3 couples reacted at 250oC and In4Te3, InTe and In3Te3-x(Sb,Bi)x phases in the In/(Sb,Bi)2Te3 at 250oC are observed. All the phase micrographs and the compositions are determined using Scanning Electron Microscope (SEM) and electron probe microanalysis (EPMA). The crystal diffractions and invariant temperatures were examined using X-ray powder diffraction (XRD) and differential thermal analysis (DTA), respectively.

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