2006 Fiscal Year Final Research Report Summary
Research on THz laser utilizing deep impurities in semiconductors
| Project/Area Number |
17540297
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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 | Osaka Kyouiku University |
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Principal Investigator |
NAKATA Hiroyasu Osaka Kyoiku University, Fac, Education, Prof., 教育学部, 教授 (60116069)
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| Co-Investigator(Kenkyū-buntansha) |
FUJII Kenichi Osaka University, Dep. Physics, Associate Prof., 大学院理学研究科, 助教授 (10189988)
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| Project Period (FY) |
2005 – 2006
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| Keywords | THz / semi conductor / quantum electronics |
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| Research Abstract |
We have confirmed THz laser oscillation in Si : P and discussed possibility of THz laser oscillation by investigating impurity level by infrared photoconductivity in Ge : As, Ge : Zn and Ge : Te. DLR Institute in Germany supplied a Si : P sample of 5×7×7mm^3 rectangular shape with six parallel surfaces polished exactly. It was placed in liquid He and excited by 1MW TEA CO_2 laser. THz emission was detected a Ge : As detector. We confirmed lasing because emission intensity is sensitive to the incident angle of excitation light and the emission has a threshold in excitation intensity dependence. In order to characteristic of the detector infrared photoconductivity was measured in Ge : As and Ge : Zn eicited by TEA CO_2 laser. Super and sub linear dependences were observed fofr Ge : As and Ge : Zn, respectivevly. We measured infared photoconductivity to study impuritylevel in Ge in detail. In addition to phonon absorption, decrease of phohtoconductivity was observed around 120 and 115 meV in Ge : As and Ge : Zn, respectively. Both of the m correspond to transition of a free electron to the excited state of impurity by emitting LO phonon. In Ge : Te, structures like Fano resonances were observed and the ionization energy of ls(T2) excited state was estimated to be 10.5meV. The THz laser utilized by deep impurities in Ge may oscillate around 5meV much lower than Si : P laser because the ls(T2) state is considerably shallow in spite of a deep impurity.
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Research Products
(6 results)
