| Project/Area Number |
16360155
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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 |
Electronic materials/Electric materials
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| Research Institution | Kobe University |
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Principal Investigator |
WADA Osamu Kobe University, Faculty of Engineering, Department of Electrical and Electronics Engineering, Professor, 工学部, 教授 (90335422)
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| Co-Investigator(Kenkyū-buntansha) |
KITA Takashi Kobe University, Faculty of Engineering, Department of Electrical and Electronics Engineering, Assistant Professor, 工学部, 助教授 (10221186)
EKAWA Mitsuru Fijutsu Laboratories Ltd., Nanotechnology Research center, Senior Researcher, フォトノベルテクノロジー研究所, 主任研究員 (70213527)
中田 義昭 (株)富士通研究所, フォトノベルテクノロジー研究所, 主任研究員
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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 |
¥14,600,000 (Direct Cost: ¥14,600,000)
Fiscal Year 2005: ¥4,300,000 (Direct Cost: ¥4,300,000)
Fiscal Year 2004: ¥10,300,000 (Direct Cost: ¥10,300,000)
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| Keywords | optical communication devices / quantum dots / semiconductor optical amplifier / atomic layer nitridation / polarization dependence / optical communication wavelength / 原子層窒化 / 光通信デバイス / 長波長動作 / 偏向依存性 |
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| Research Abstract |
This research was conducted for developing a novel technique of controlling quantum dot properties with an emphasis on the wavelength and polarization dependence by utilizing multiple parameters such as the dot shape and atomic composition, and stress applied to the dot. This target was taken up because of its importance in real world application of quantum dots to optical communication devices such as semiconductor optical amplifiers (SOAs) and switches.
A unique MBE growth technique of quantum dots has been developed by introducing an atomic-layer nitridation step using plasma nitrogen source just after ordinary SK-mode growth of InAs quantum dots on GaAs substrates. This process has been optimized to exhibit intense emission at the wavelength of 1.3□m at room temperature. Transmission electron microscopy has shown existence of nitrided Layer on top of the dot surface, and the generation of dislocation has been shown to be suppressed when the nitridation time is optimized.
Control of quantum dot shape has been found to be extremely important in determining the polarization properties of quantum dots when used in horizontal device structures as seen in most of conventional SOAs. We have succeeded to adjust the polarization direction by optimizing the shape of columnar quantum dot in which multiple dot layers are stacked to eventually make a spherical dot. Optimum staking layer numbers have been demonstrated for equal TE vs. TM polarization intensities in the edge emission. The control of stress on the dot by changing the capping layer composition (GaAs or InGaAs) has also been confirmed to be useful in controlling the polarization properties. Such polarization control has been also demonstrated to be effective under optical gain, which supports the application of this technique in real devices.
Thus multiple parameter control of quantum dots is promising technique in developing practical quantum dot optical devices in the long wavelength region.
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