Dresden 2014 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 89: Metamorphic structures: Bringing together incompatible materials I (Focus session with DF)
HL 89.9: Talk
Thursday, April 3, 2014, 12:30–12:45, POT 251
Optical and structural investigations of the effect of barrier growth on GaInN quantum well structures — •Fedor Alexej Ketzer, Heiko Bremers, Torsten Langer, Uwe Rossow und Andreas Hangleiter — Institut für Angewandte Physik, Technische Universität Braunschweig
We study the influence of the growth of the barriers in GaInN multiple quantum wells (MQW) on structural and optical parameters of the wells. Therefore several MQWs were grown via low pressure MOVPE. Because the growth with H2 as carrier gas is known to impede the incorporation of indium but is necessary during the growth of other layers, and therefore present in the reactor and structure, we investigate the effects of H2 on the structure. We compare MQWs with different additional H2 buffer gas flows during barrier growth with our reference samples with N2 carrier gas. The growth parameters for the wells of all samples remain unchanged and lead to a nominal thickness of 2 nm with an indium content of 18 %. While the well thickness and indium content determined by photoluminescence do not differ for the reference samples without and the samples with H2 buffer gas, the data of high resolution X-ray diffraction contradicts at a first glance. Here we see a drastically lower effective indium content of 7 %. This can only be explained by a strong inhomogeneity of the quantum wells and that only a small fraction of the quantum well area remains after growth. The influence of these inhomogeneities on the optical parameters and the internal quantum efficiency is discussed in detail.