2007 Fiscal Year Final Research Report Summary
Spatial and Temporal Characterization of Nonradiative recombination centers by Using the Method of Two-Wavelength Excited Photoluminescence
| Project/Area Number |
17360006
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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 |
Applied materials science/Crystal engineering
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| Research Institution | Saitama University |
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Principal Investigator |
KAMATA Norihiko Saitama University, School of Science and Engineering, Professor (50211173)
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| Co-Investigator(Kenkyū-buntansha) |
HONDA Zentaroh Saitama University, School of Science and Engineering, Assoc. Prof. (30332563)
ARAKAWA Yasuhiko University of Tokyo, RCAST, Professor (30134638)
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| Project Period (FY) |
2005 – 2007
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| Keywords | nonradiative recombination center / characterization / photoluminescence / optical properties / quantum wel |
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| Research Abstract |
The method of two-wavelength excited photoluminescence (TWEPL) has been improved as a quantitative one by utilizing the trap-filling effect after Kamata's work at 1995. By introducing an EM-CCD camera with high sensitivity and S/N ratio, and the microscopic optics with magnification change and observation-window mechanisms, we established an improved TWEPL system in order to" trace" the generation of defects and" map" their in-plane distribution in an observing area on a wafer.
Based on the TWEPL system, we detected nonradiative recombination (NRR) centers in InAs/GaAs quantum dot, InGaN/InGaN and GaN/A1GaN quantum well structures. The observation of an irreversible change in the below-gap excitation (BGE) effect in a GaN/AIGaN quantum well was attributed to a surface defect formation due to Nd: YAG laser irradiation as a BGE source. The distribution of NRR centers was exemplified by the segmented measurements of the TWEPL as well as conventional PL.
These spatial and temporal studies are considered to be important steps for analyzing the origin and eliminating scheme of each NRR center, utilizing the merit of non-distractive and non-contacting nature of TWEPL measurement.
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