Title page for etd-0710116-114131


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URN etd-0710116-114131
Author Yen-Te Cho
Author's Email Address No Public.
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Department Materials and Optoelectronic Science
Year 2015
Semester 2
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Phase Diagrams of Ternary Ag–Ga–Te System and Thermoelectric Properties of Chalcopyrite AgGaTe2
Date of Defense 2016-06-29
Page Count 218
Keyword
  • Ag-Ga-Te
  • chalcopyrite structure
  • phase diagram
  • thermoelectric
  • Abstract 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.
    Advisory Committee
  • Ker-Chang Hsieh - chair
  • Sinn-Wen Chen - co-chair
  • P. C. Wei - co-chair
  • H.-J. Wu - advisor
  • Files
  • etd-0710116-114131.pdf
  • Indicate in-campus at 5 year and off-campus access at 5 year.
    Date of Submission 2016-08-10

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