Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 25: Poster Session: GaN - Optical Properties & Preparation and Characterization & Devices

HL 25.19: Poster

Monday, March 26, 2012, 16:00–19:00, Poster D

Optimization of the internal and external quantum efficiency of high In content GaInN LED structures — •Fedor Alexej Ketzer, Holger Jönen, Ailun Zhao, Heiko Bremers, Uwe Rossow, and Andreas Hangleiter — Institut für Angewandte Physik, TU Braunschweig

We investigate high indium content GaInN based light emitting diodes grown via low pressure MOVPE. The efficiency of such structures is rather small due to the high indium content. In order to improve the efficiency we study the growth of the p-doped GaN layer and rapid thermal annealing (RTA), needed to activate the p-dopants (Mg). Due to the high thermal load these processes influence the quantum well (QW) and therefore the internal quantum efficiency (IQE). These influences appear to raise with higher indium content.

For this purpose the IQE before and after RTA is compared with the external quantum effiency (EQE). Also conditions during RTA and growth of the layers following the QW were modified to examine changes in emission spectra and efficiency. The IQE was determined by temperature dependent photoluminescence and the EQE was determined by electroluminescence. With these results the growth conditions of the active region and their following layers can be optimized for high internal and external quantum efficiencies.