Regensburg 2007 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 25: Quantum dots and wires: Optical properties II

HL 25.11: Talk

Tuesday, March 27, 2007, 16:45–17:00, H17

Phonon interactions in InGaAs/GaAs quantum dots — •Stefan Werner, Patrick Zimmer, André Strittmatter, and Axel Hoffmann — Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstr. 36, D-10623, Berlin, Germany

In recent years, carrier-phonon interactions in semiconductor quantum dots have attracted considerable attention. They are important to understand the electronic properties of such systems, like carrier relaxation processes. Some are convinced that carriers confined in quantum dots are strongly coupled to the longitudinal optical (LO) vibrations of the semiconductor lattice. We report on exciton-phonon interactions in InGaAs/GaAs quantum dots. Photoluminescence and time-resolved experiments were performed on different MOCVD-grown InGaAs/GaAs samples to observe and investigate varying phonon interactions. In our measurements we observed photoluminescence peaks constantly shifting with varied excitation energy. The energy gap between the laser-peak and the observed two-peak structure remained unchanged. The ΔE-values of 33,8 meV and 36,9 meV precisely fit to the QD LO-Phonon mode and to the interface mode, respectively. The very short radiative lifetime also points to inelastically scattered phonons, i.e. Raman scattering.