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Proceedings Paper

Analysis of the emission characteristics of photonic crystal LEDs
Author(s): Ch. Wiesmann; K. Bergenek; N. Linder; U. T. Schwarz
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Paper Abstract

Photonic crystals are known to enhance the extraction efficiency of LEDs and simultaneously shaping the emission pattern. In order to determine the radiation pattern we developed a model based on coupled mode theory that takes into account the lattice pattern, etch depth and the mode distribution. From a basic geometrical consideration a fundamental limit for the directionality is predicted. The calculations fit well to experimental data obtained from green InGaN LEDs incorporating a hexagonal PhC revealing a maximum directionality of 31% within 30°. Additional FDTD simulations were performed for determining quantitatively the extraction efficiency of PhC LEDs compared to LEDs with a roughened surface. Despite its lower overall extraction efficiency, the PhC LED outperforms a standard LED with surface roughening within an acceptance angle of 34° due to the higher directionality of the extracted light.

Paper Details

Date Published: 21 April 2008
PDF: 9 pages
Proc. SPIE 6989, Photonic Crystal Materials and Devices VIII, 69890L (21 April 2008); doi: 10.1117/12.780572
Show Author Affiliations
Ch. Wiesmann, Osram Opto Semiconductors GmbH (Germany)
Univ. Regensburg (Germany)
K. Bergenek, Osram Opto Semiconductors GmbH (Germany)
N. Linder, Osram Opto Semiconductors GmbH (Germany)
U. T. Schwarz, Univ. Regensburg (Germany)

Published in SPIE Proceedings Vol. 6989:
Photonic Crystal Materials and Devices VIII
Richard M. De La Rue; Ceferino López; Michele Midrio; Pierre Viktorovitch, Editor(s)

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