By Topic

Absorption and light scattering in InGaN-on-sapphire- and AlGaInP-based light-emitting diodes

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

12 Author(s)
Schad, Sven-Silvius ; Dept. of Optoelectron., Univ. of Ulm, Germany ; Neubert, B. ; Eichler, Christoph ; Scherer, M.
more authors

Different experimental and simulation techniques aiming at a better understanding of lateral mode absorption in light-emitting diodes (LEDs) are presented in this paper. A measurement of transmitted power versus propagation distance allows us to derive the absorption losses of LED layer structures at their emission wavelength. Two models for the observed intensity distribution are presented: one is based on scattering, whereas the other relies on selective absorption. Both models were applied to InGaN-on-sapphire-based LED structures. Material absorption losses of 7 cm-1 for the scattering model and 4 cm-1 for the absorbing-layer model were obtained. Furthermore, these values are independent of the emission wavelength of the layer structure in the 403-433-nm range. The losses are most likely caused by a thin highly absorbing layer at the interface to the substrate. In a second step, interference of the modal field profile with the absorbing layer can be used to determine its thickness (d=75 nm) and its absorption coefficient (α ≈ 3900 cm-1). This method has also been tested and applied on AlGaInP-based layer structures emitting at 650 nm. In this case, the intensity decay of α=30 cm-1 includes a contribution from the absorbing substrate.

Published in:

Lightwave Technology, Journal of  (Volume:22 ,  Issue: 10 )