Regensburg 2013 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 68: Poster Session: GaN: devices & preparation & characterization; III-V semiconductors; Photonic crystals; Semiconductor lasers

HL 68.4: Poster

Wednesday, March 13, 2013, 16:00–20:00, Poster A

Effect of high thermal stress on the internal quantum efficiency of GaInN LED structures — •Fedor Alexej Ketzer, 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). Both changes in the geometry of the QW due to diffusion and generation of defects are possible. Therefore the effects can be attributed to changes in radiative or nonradiative recombination as well as a combination of both.

To distinguish the effects on the different recombination processes, the IQE and photoluminescence spectra before and after RTA are compared. Furthermore conditions during RTA and growth of the structures were modified to endorse the results. The IQE was determined by temperature and excitation power dependent photoluminescence. These results help optimize growth and processing of LED structures to achieve high internal and external quantum efficiencies.