Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 53: Poster II

HL 53.10: Poster

Mittwoch, 9. März 2016, 09:30–13:30, Poster A

Metamorphic buffer layers on GaAs for the deposition of InGaAs quantum dots — •Julian Kluge, Matthias Paul, Michael Jetter, and Peter Michler — Institut für Halbleiteroptik und funktionelle Grenzflächen, University Stuttgart and Research Centers Scope and IQST, Allmandring 3, Universität Stuttgart

The interest in In(Ga)As semiconductor quantum dots (QDs) as sources for entangled or indistinguishable photons has increased in the last years due to a need for non-classical light generation in quantum information or quantum cryptography. For an implementation in fiber-coupled networks, emission wavelengths in the telecommunication bands at 1.31 µm or 1.55 µm are desirable to minimize absorption losses. The high strain in InAs QDs directly deposited on GaAs leads to emission wavelengths below 1 µm. A shift to wavelengths above 1.3 µm is possible by depositing the QDs on InP substrates, thus, decreasing the lattice mismatch. InGaAs metamorphic buffer (MB) layers can substitute InP substrates. We grow MB layers on GaAs substrates for the deposition of In(Ga)As QDs with emission in the range of the telecommunication bands. The Indium content in the MB is increased gradually to adjust the lattice constant and decrease the lattice mismatch between the QDs and the growth surface. In X-ray diffraction experiments, the residual strain on the surface and the Indium content is determined with the help of reciprocal space maps of the symmetrical (004) and asymmetrical (224) reflexes. The surface roughness of the partially relaxed buffers is investigated by atomic force microscopy (AFM). A smooth surface is a prerequisite for the deposition of QDs.