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Proceedings Paper

Yellow photoluminescence in MOCVD-grown n-type GaN
Author(s): E. Fred Schubert; W. Grieshaber; Karim S. Boutros; Joan Marie Redwing
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Paper Abstract

The near-band gap and the 'yellow' optical transitions in n- type GaN grown by MOCVD have been studied by photoluminescence experiments. The excitation density ranged from 5 X 10-6 W/cm-2 to 50 W/cm-2. The UV PL intensity increases linearly in the entire range of excitation density. The yellow PL intensity exhibits a linear dependence oat low excitation densities and a square-root dependence at high excitation densities. A theoretical model is developed describing the intensity of the two radiative transition between continuum states and one defect level deep in the band gap as a function of the excitation density, free carrier and defect concentrations. The calculated dependences of the two luminescence channels follow power laws with exponents of 1/2 and 1 depending on excitation density. These dependences are in very good agreement with experimental results. The measured intensity of the yellow luminescence does not saturate at high excitation densities. This rules out the possibility that the yellow PL could arise from a sequential transition via two deep levels in the gap. It is shown that the intensity modulation that frequently appears in the PL spectra is caused by a micro-cavity which is formed by the semiconductor-substrate and semiconductor-air interfaces. Finally, the dependence of the yellow luminescence intensity on n-type doping concentration indicates that the deep center causing the yellow luminescence is an acceptor-like level.

Paper Details

Date Published: 7 April 1998
PDF: 10 pages
Proc. SPIE 3279, Light-Emitting Diodes: Research, Manufacturing, and Applications II, (7 April 1998); doi: 10.1117/12.304430
Show Author Affiliations
E. Fred Schubert, Boston Univ. (United States)
W. Grieshaber, Boston Univ. (United States)
Karim S. Boutros, Advanced Technology Materials, Inc. (United States)
Joan Marie Redwing, Advanced Technology Materials, Inc. (United States)

Published in SPIE Proceedings Vol. 3279:
Light-Emitting Diodes: Research, Manufacturing, and Applications II
E. Fred Schubert, Editor(s)

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