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HL: Fachverband Halbleiterphysik

HL 24: Poster Session II

HL 24.17: Poster

Dienstag, 13. März 2018, 18:30–20:30, Poster F

Simulating Optical Signals of the Spatiotemporal Dynamics of Carrier Capture Processes — •Frank Lengers, Roberto Rosati, Tilmann Kuhn, and Doris E. Reiter — Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Str. 10, 48149 Münster

Carrier capture processes are frequently encountered in semiconductor structures as, e.g., scattering from the wetting layer to an embedded quantum dot or as trapping of carriers in defects or strain-induced potentials. Those processes happen on an ultrafast timescale and on nanometric length scales such that a quantum description is necessary. These scales require an ultrafast and localized measurement as found in spatially resolved pump-probe measurements.
In this contribution we study the optical signals resulting from the phonon-mediated carrier-capture from a GaAs quantum wire into an embedded quantum dot. To this end we consider a two-band model coupled to a light field and under the influence of carrier-carrier and carrier-phonon interaction. The microscopic description of the carrier-phonon scattering is treated within a Markovian Lindblad single-particle (LSP) approach, which is able to account for the local nature of carrier-phonon scattering [1]. We propose a two-pulse measurement: The first pulse excites a wave packet far from the quantum dot which travels onto the quantum dot where the local capture occurs. The dynamics of the capture process is probed by a second pulse. We find that the capture dynamics is clearly reflected in the probe spectra.
[1] Rosati et al, Phys. Rev. B 95, 165302 (2017)