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Proceedings Paper

Scanning near-field optical spectroscopy of AlGaN-based light emitting diodes
Author(s): Andrea Pinos; Saulius Marcinkevičius
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Paper Abstract

Electroluminescence of 285 and 340 nm AlGaN quantum well light emitting diodes (LEDs) has been studied by scanning near-field optical spectroscopy. In the 285 nm devices, the near-field scans revealed hexagonal cross hatch microcracks that can be related to strain relaxation. Besides, μm size areas emitting with a higher intensity and at a longer wavelength, presumably, due to lower AlN molar fraction, have been observed. Near-field scans performed during subsequent days revealed that with time, intensity from these spots increases and emission wavelength shifts to the red, indicating further change in the quantum well alloy composition. This has allowed distinguishing a novel LED aging mechanism that involves locally increased current, heating and Al atom migration. For the 340 nm emitting device with lower Al content in the active region, no such features have been observed.

Paper Details

Date Published: 10 March 2010
PDF: 8 pages
Proc. SPIE 7602, Gallium Nitride Materials and Devices V, 76020T (10 March 2010); doi: 10.1117/12.840403
Show Author Affiliations
Andrea Pinos, Royal Institute of Technology (Sweden)
Saulius Marcinkevičius, Royal Institute of Technology (Sweden)

Published in SPIE Proceedings Vol. 7602:
Gallium Nitride Materials and Devices V
Jen-Inn Chyi; Yasushi Nanishi; Hadis Morkoç; Cole W. Litton; Joachim Piprek; Euijoon Yoon, Editor(s)

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