2005 Fiscal Year Final Research Report Summary
Development of Large Area and High Performance Radiation Imaging Detectors for Medical Use
| Project/Area Number |
15300181
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Medical systems
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| Research Institution | Nagoya Institute of Technology |
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Principal Investigator |
YASUDA Kazuhito Nagoya Institute of Technology, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (60182333)
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| Co-Investigator(Kenkyū-buntansha) |
NIRAULA Madan Nagoya Institute of Technology, Graduate School of Engineering, Associate Professor, 大学院・工学研究科, 助教授 (20345945)
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| Project Period (FY) |
2003 – 2005
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| Keywords | Radiation detector / Cadmium Telluride / Metalorganic Vapor Phase Epitaxy / Imaging detector |
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| Research Abstract |
Development of large area and high performance radiation imaging detectors using thick CdTe layers grown by Metalorganic vapor phase epitaxy (MOVPE) has been studied. The following 3 major achievements were obtained.
1.Development of CdTe/n^<+->GaAs heterojunction diode detectors.
Heterojunction diode detectors were fabricated using thick p-CdTe layers grown on n^<+->GaAs substrates by MOVPE. Detection and energy discrimination capabilities for the incident gamma ray of 59 keV from Am source were confirmed for the first time. Optimization of the detector structure was also carried out.
2.Development of direct growth technique of CdTe lavers on Si substrates by MOVPE.
Growth of single crystal CdTe layers directly on Si substrates by MOVPE was achieved for the first time. As a pretreatment before the CdTe growth on Si, the Si substrates were annealed with GaAs pieces in the hydrogen environment. Growth of high quality CdTe thick layers, which were necessary for radiation detectors, was also achieved by using the following growth technique. After the growth of thin CdTe layers on Si substrates, residual stress in the grown layers were relaxed, and thick CdTe layers were grown on them.
3.Development of CdTe/n^<+->Si heterojunction diode detectors.
On the basis of results obtained in 1 and 2 above, heterojunction diode detectors using thick p-CdTe layers grown directly on n^<+->Si substrates were fabricated. The detectors were confirmed to have good electrical characteristics. Improvements of the detector performance were also studied.
Throughout the above studies, fundamental techniques which were inevitable to realize the purposed detectors were established.
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