| Project/Area Number |
10305028
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
電子デバイス・機器工学
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| Research Institution | University of Tokyo |
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Principal Investigator |
ARAKAWA Yasuhiko Institute of Industrial Science, University of Tokyo, Professor, 生産技術研究所, 教授 (30134638)
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| Co-Investigator(Kenkyū-buntansha) |
SOMEYA Takao Research Center for Advanced Science and Technology, Lecturer, 先端科学技術研究センター, 講師 (90292755)
HIRAKAWA Kazuhiko Institute of Industrial Science, University of Tokyo, Associate Professor, 生産技術研究所, 助教授 (10183097)
SAKAKI Hirouki Institute of Industrial Science, University of Tokyo, Professor, 生産技術研究所, 教授 (90013226)
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| Project Period (FY) |
1998 – 2000
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| Keywords | Quantum nanostructures / Quantum casecade lasers / Semiconductor lasers / MOCVD / MBE / Nanostructures / Quantum wells / heterostructures |
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| Research Abstract |
This research project is organized to investigate growth technique and physics of semiconductor heterostructures for realizing 1.5μm-wavelength semiconductor lasers with quantum cascade structures. In particular, we investigate intersubband transition in GaN/AlGaN single heterostructures with large band discontinuity.
First, we fabricated AlGaN/GaN single heterostructures ob A1203 substrates by MOCVD and achieved high electron mobility up to 2000cm2/Vs at room temperature, which clearly demonstrates the heterointerface of high quality. We performed absorption measurement using FTIR and found an absorption peak at 270 meV corresponding to the energy difference between the ground and the first excited states. In contrast to the energy difference of 30 emV at the GaAs/AlGaAs single heterstructure, the big energy difference in GaN/AlGaN is larger by one order of magnitude, which is attributed to strong piezoelectric field effects.
In addition, intersuband transition is investigated for various quantum wells with different number and well-thickness. With the increase of the total number of quantum wells, the shift of absorption peak was observed. This is due to the relaxation of strain effects with the increase of the numer of quantum wells. AT present stage the shortest wavelength so far obtained is 1.7μm.
In summary, the research project has succeed in demonstrated importance of intersubband transition in GaN/AlGaN heterostructures or quantum wells for 15μm light emitting laser applications with unipolar devices.
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