Regensburg 2010 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 41: Quantum Dots and Wires: Preparation and Characterization II
HL 41.5: Vortrag
Mittwoch, 24. März 2010, 12:00–12:15, H13
MOVPE overgrowth of InN quantum dot like structures — •Christian Meißner1,2, Michael Högele1, Raimund Kremzow1, Markus Pristovsek1, and Michael Kneissl1 — 1Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstraße 36, EW6-1, 10623 Berlin — 2ISAS - Institute for Analytical Sciences, Albert-Einstein-Straße 9, 12489 Berlin
Indium nitride (InN) quantum dots could be used an alternative material for applications at the standard telecommunication wavelength of 1.55 µm. We showed that the density and size of InN quantum dots grown in Volmer-Weber growth mode can be controlled by growth temperature and total amount of InN on the surface. For light emitting devices those quantum dot like structures need to be overgrown. Therefore, we studied systematically the overgrowth process by MOVPE of InN quantum dots on GaN/sapphire with a density of 1010 cm−2. Different capping strategies were monitored by in-situ ellipsometry which allows investigations on a submonolayer scale of the InN/GaN system with 11% lattice mismatch. Additional characterisation was done by atomic force microscopy, x-ray and photoluminescence measurements.
The main problem of indium segregation from InN QDs into the first capping layers and the formation of InGaN is observed by XRD with a gallium content of less than 20%. Thus for overgrowth a high growth rate is needed, but the material quality must still be maintained. Further investigations with InGaN capping layers to reduce the strain during overgrowth have been done.