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Proceedings Paper

Carrier localization in InGaN-based light-emitting diodes (Conference Presentation)
Author(s): Felix Nippert; Sergey Yu. Karpov; Markus R. Wagner; Gordon Callsen; Thomas Kure; Bastian Galler; Hans-Jürgen Lugauer; Martin Strassburg; Axel Hoffmann

Paper Abstract

We review recent advances in the understanding of the green gap phenomenon, the drastic reduction of quantum efficiency of c-plane InGaN/GaN light-emitting diodes (LEDs) towards the green spectral region. In particular, we have decoupled the contributions of Shockley-Read-Hall recombination, quantum-confined Stark effect and hole localization in the random alloy. We show that the latter, significantly increasing with Indium content, plays a crucial role in the reduction of efficiency, as localized holes do not only possess lower overlap with delocalized electrons in the quantum well, but also appear to enhance Auger recombination. For our study we use an electro-optical pump and probe scheme[1], which is most suitable to obtain differential carrier lifetimes in device operating conditions. In combination with conventional pulsed electroluminescence measurements, the internal quantum efficiency and recombination rates of the different processes can be determined. Temperature-dependent analyses then allow to assign recombination losses to the different underlying limitations (i.e. random alloying, polarity, defect density)[2]. [1] F. Nippert et al., Japanese Journal of Applied Physics 55, 05FJ01 (2016) [2] F. Nippert et al., Applied Physics Letters 109, 161103 (2016)

Paper Details

Date Published: 14 March 2018
Proc. SPIE 10554, Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XXII, 105540D (14 March 2018); doi: 10.1117/12.2292437
Show Author Affiliations
Felix Nippert, Technische Univ. Berlin (Germany)
Sergey Yu. Karpov, STR Group-Soft Impact Ltd. (Russian Federation)
Markus R. Wagner, Technische Univ. Berlin (Germany)
Gordon Callsen, Technische Univ. Berlin (Germany)
Thomas Kure, Technische Univ. Berlin (Germany)
Bastian Galler, OSRAM Opto Semiconductors GmbH (Germany)
Hans-Jürgen Lugauer, OSRAM Opto Semiconductors GmbH (Germany)
Martin Strassburg, OSRAM Opto Semiconductors GmbH (Germany)
Axel Hoffmann, Technische Univ. Berlin (Germany)

Published in SPIE Proceedings Vol. 10554:
Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XXII
Jong Kyu Kim; Michael R. Krames; Martin Strassburg; Li-Wei Tu, Editor(s)

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