| Project/Area Number |
16540283
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Condensed matter physics I
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| Research Institution | Niigata University |
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Principal Investigator |
IZUMIKAWA Takuji Niigata University, Radioisotope Center, Associate Professor, アイソトープ総合センター, 助教授 (60282985)
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| Co-Investigator(Kenkyū-buntansha) |
MINAMISONO Tadanori Fukui University of Technology, Department for the Application of Nuclear Technology, Professor, 環境生命未来工学科, 教授 (20028210)
OHYA Susumu Niigata University, Institute of Science and Technology, Professor, 自然科学系, 教授 (90092676)
MATSUTA Kensaku Osaka University, Department of Physics, Associate Professor, 大学院・理学研究科, 助教授 (50181722)
OHTSUBO Takashi Niigata University, Institute of Science and Technology, Associate Professor, 自然科学系, 助教授 (70262425)
GOTO Jun Radioisotope Center, Assistant, アイソトープ総合センター, 助手 (90370395)
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 2005: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2004: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Keywords | Semiconductor / Lattice Defect / Atomic Jump / NMR / Unstable Nuclei |
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| Research Abstract |
The beta-NMR measurements of the boron impurity in germanium were performed. The obtained results are as follows. Three resonances were found : a sharp resonance and a broad one around the Larmor frequency, a resonance at vqSplit=190 kHz. In the same manner as silicon, these three resonances were expected to correspond to the substitutional site (Bs), the site which shows polycrystal pattern (Bx), and the <111> axial symmetrical site (Bns), respectively. While the fraction of Bns is almost constant of 30 % below the temperature of 250 K, above 300 K the resonance disappears. This disappearance is also similar with the case of silicon, i.e., the spin-lattice relaxation should be caused by the fluctuation of the internal field due to the atomic jumps. The temperature dependence of the Bs+Bx was slightly different to the silicon case. Around the room temperature it decreases and makes a depression. One explanation for it may be that the chance for the interaction of Bs or Bx with the vacancy created by the implantation increases with the temperature, and it follows destruction of the polarization.
In order to confirm the model of the atomic jump, the temperature dependence of the fractions of each site were measured under the different external magnetic fields. As a result, the temperature at which the NMR signal disappears agreed with the expected value by our model. This supports the validity of the atomic jump model.
The nitrogen impurity in the compound semiconductor TiO2 and ZnO was also investigated. The electric field gradient at the nitrogen impurity in ZnO was measured. The nitrogen impurity in TiO2 locates at oxygen substitutional site and interstitial lattice site. While the substitutional nitrogen seems to be immobile, the defect around the substitutional nitrogen and the interstitial nitrogen seems to be mobile thermally.
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