Berlin 2008 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 45: GaN devices
HL 45.7: Talk
Thursday, February 28, 2008, 11:00–11:15, EW 202
Temperature and current dependent electroluminescence measurements on colour-coded Multiple Quantum Well Light Emitting Diodes — •Werner Bergbauer1,2, Ansgar Laubsch1, Matthias Peter1, Tobias Mayer1, Stefan Bader1, Günther Benstetter2, Raimund Oberschmid1, and Berthold Hahn1 — 1OSRAM Opto Semiconductors GmbH, 93055 Regensburg, Germany — 2FH Deggendorf, 94469 Deggendorf, Germany
As the efficiency and the luminous flux have been increased enormously in the last few years, today Light Emitting Diodes (LEDs) are even pushed to applications like general lighting and Home Cinema Projection. Still, InGaN / GaN heterostructure based LEDs suffer from loss-mechanisms like non-radiative defect and Auger recombination, carrier leakage and piezo-field induced carrier separation. To optimize the high current efficiency we evaluated the benefit of Multiple Quantum Well (MQW) compared to Single Quantum Well (SQW) LEDs. Temperature dependent electroluminescence of colour-coded structures with different Indium content in certain Quantum Wells was measured. The experiments demonstrated a strong temperature and current dependence of the MQW operation. The comparison between different LED structures showed effectively the increased LED performance of those structures which operate with a well adjusted MQW active area. Due to the enhanced carrier distribution in the high current range, these LEDs show a higher light output and additionally a reduced wavelength shift.