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Proceedings Paper

Optical properties and material studies of InGaN/GaN multi-quantum well light emitting diode wafers with different structures
Author(s): T. W. Kuo; T. Y. Lin; Z. C. Feng; W. Liu; S. J. Chua; H. L. Tsai; J. R. Yang; Y. S. Huang; Ian T. Ferguson; W. Lu
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Paper Abstract

Three blue emission multi-quantum well (MQW) light emitting diode (LED) samples with different indium composition and different amount of quantum wells were studied. From x-ray diffraction and transmission electron microscopy experimental measurements, the period thickness and indium composition of the sample have been obtained. The temperature dependent photoluminescence (PL) shows that the signal from InGaN/GaN samples was influenced by two kinds of factors. One is the band to band transition of InGaN; another is the localization effect caused by the non-uniformity of the In composition in In-rich samples. While the temperature increases, full width half maximum becomes larger, and the signal tends to shift to the red side. Through theoretical fitting on the temperature dependent PL data, the activation energies (Ea) of the InGaN multi-quantum well samples were obtained. Time-resolved photoluminescence (TRPL) results show that as the indium composition increases and the QW number increases, a longer decay time will get. From the results of photoluminescence excitation (PLE) experiment, a large Stokes shift (SS) was observed. The large Stokes shift can be attributed to the variation of indium composition or the quantum confined Stark effect (QCSE). Also, the Photoluminescence spectra exhibit weak blue peaks and the optical intensity is improved by increasing the number of wells.

Paper Details

Date Published: 18 August 2009
PDF: 13 pages
Proc. SPIE 7422, Ninth International Conference on Solid State Lighting, 74220Q (18 August 2009); doi: 10.1117/12.825895
Show Author Affiliations
T. W. Kuo, National Taiwan Univ. (Taiwan)
T. Y. Lin, National Taiwan Univ. (Taiwan)
Z. C. Feng, National Taiwan Univ. (Taiwan)
W. Liu, Institute of Materials Research and Engineering (Singapore)
S. J. Chua, Institute of Materials Research and Engineering (Singapore)
H. L. Tsai, National Taiwan Univ. (Taiwan)
J. R. Yang, National Taiwan Univ. (Taiwan)
Y. S. Huang, National Taiwan Univ. of Science and Technology (Taiwan)
Ian T. Ferguson, Georgia Institute of Technology (United States)
W. Lu, Fisk Univ. (United States)

Published in SPIE Proceedings Vol. 7422:
Ninth International Conference on Solid State Lighting
Ian T. Ferguson; Christoph Hoelen; Jianzhong Jiao; Tsunemasa Taguchi, Editor(s)

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