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Proceedings Paper

Effects of buffer layer growth conditions on the GaN epilayer quality by MOCVD
Author(s): Fuh-Shyang Juang; Yan-Kuin Su; Shoou-Jinn Chang; T. K. Chu; C. S. Chen; L. W. Chi; Kin Tak Lam
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Paper Abstract

We have found that the electrical and optical properties of GaN epilayers strongly depend on buffer TMGa flow rates and NH3 flow rates. At low flow rate of 4 sccm, the buffer layer quality was good so the concentrations of undoped GaN epilayers decreased and a stronger band-edge emission of 362 nm can be observed in photoluminescence spectra. The carrier density of the films can be reduced from 1018 to 1017 cm-3 by increasing the NH3 flow rate from 0.5 up to 1 SLM and comparatively increased the near-band-edge emission. So, with a NH3 flow rate as high as 1 SLM, the GaN epilayers with good optical quality can be obtained. The excitation power density of He-Cd laser influences the photoluminescence property of GaN epilayers. At high excitation power density of 637 W/cm2, the near-band-edge luminescence (362 nm) is dominant and the deep level luminescence (near 550 nm) appears very weak. But at low excitation power density, the luminescence from defect yellow band levels is stronger than the near-band-edge transitions.

Paper Details

Date Published: 17 April 2000
PDF: 6 pages
Proc. SPIE 3938, Light-Emitting Diodes: Research, Manufacturing, and Applications IV, (17 April 2000); doi: 10.1117/12.382833
Show Author Affiliations
Fuh-Shyang Juang, National Huwei Institute of Technology (Taiwan)
Yan-Kuin Su, National Cheng Kung Univ. (Taiwan)
Shoou-Jinn Chang, National Cheng Kung Univ. (Taiwan)
T. K. Chu, National Cheng Kung Univ. (Taiwan)
C. S. Chen, National Cheng Kung Univ. (Taiwan)
L. W. Chi, Kao Yuan Institute of Technology and Commercialism (Taiwan)
Kin Tak Lam, Kao Yuan Institute of Technology and Commercialism (Taiwan)


Published in SPIE Proceedings Vol. 3938:
Light-Emitting Diodes: Research, Manufacturing, and Applications IV
H. Walter Yao; Ian T. Ferguson; E. Fred Schubert, Editor(s)

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