| Budget Amount *help |
¥19,630,000 (Direct Cost: ¥15,100,000、Indirect Cost: ¥4,530,000)
Fiscal Year 2017: ¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000)
Fiscal Year 2016: ¥5,850,000 (Direct Cost: ¥4,500,000、Indirect Cost: ¥1,350,000)
Fiscal Year 2015: ¥8,840,000 (Direct Cost: ¥6,800,000、Indirect Cost: ¥2,040,000)
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| Outline of Final Research Achievements |
The effect of room-temperature high-pressure (RTHP) treatment on the transport properties, crystal structure, and electronic structure of chalcopyrite compounds were investigated. The thermal conductivity of RTHP-treated chalcopyrite compounds is greatly reduced, which is attributed to the point defects, stacking faults, and increased grain boundaries. These defects also decrease the carrier mobility and increase the carrier concentration, resulting in lowering the electrical conductivity and Seebeck coefficient. RTHP-treated chalcopyrite compounds contains microstrains, which partially arises from a series of disorder at the cation site with a variety of degrees and geometries. Such disorder can be induced as a metastable structure by the RTHP-treatment. Electronic structure calculations clarify that such disorder at the cation site changes orbitals hybridization, which can partially explain the experimentally observed transport properties of RTHP-treated samples.
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