| Project/Area Number |
26820099
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Power engineering/Power conversion/Electric machinery
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| Research Institution | Tokyo Metropolitan University (2016)
Tokyo University of Science (2014-2015) |
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Principal Investigator |
Hirayama Naomi 首都大学東京, 理工学研究科, 特任助教 (70581750)
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| Co-Investigator(Renkei-kenkyūsha) |
IIDA Tsutomu 東京理科大学, 基礎工学部, 教授 (20297625)
NISHIO Keishi 東京理科大学, 基礎工学部, 教授 (90307710)
FUNASHIMA Hiroki 神戸大学, 理学研究科, 講師 (60434049)
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| Project Period (FY) |
2014-04-01 – 2017-03-31
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| Project Status |
Completed (Fiscal Year 2016)
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| Budget Amount *help |
¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000)
Fiscal Year 2016: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2015: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2014: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
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| Keywords | 物性理論 / 半導体物性 / 再生可能エネルギー / 熱電物質 / マグネシウムシリサイド / 不純物添加 / 第一原理計算 / 熱電効果 / 不純物ドープ効果 / 格子定数 / 不純物サイト / 擬ポテンシャル法 / FLAPW法 / KKRグリーン関数法 |
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| Outline of Final Research Achievements |
We have theoretically investigated impurity doping effects on the structural, electronic, and thermoelectric properties of Mg2Si in order to provide guidelines for improving the energy conversion efficiency and the stability of the system. We first examined the validity of first principles calculation codes by comparing their calculation results. We next discussed the stability of impurity-doped systems by the formation energy calculation. As a result, Sb is a stable n-type dopant; in contrast, Ag-doped systems have comparable formation energies for the Mg, Si, and interstitial sites, which accounts for the instability in the conductivity of Ag-doped Mg2Si. Furthermore, F and Cl act as p-type dopants when inserted into the cell. We then obtained the doping concentrations to provide the maximum thermoelectric power. We also investigated crystal defects: vacancies of Mg or Si, and the insertion of extra atoms into crystals, to elucidate their influence on the carrier transport of Mg2Si.
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