Magnetospectroscopy of excited states in charge-tunable GaAs/AlGaAs [111] quantum dots Article - Juin 2016

M. Durnev, M. Vidal, Louis Bouet, Thierry Amand, M. Glazov, L. Ivchenko, P. Zhou, G. Wang, T. Mano, N. Ha, T. Kuroda, Xavier Marie, K. Sakoda, B. Urbaszek

M. Durnev, M. Vidal, Louis Bouet, Thierry Amand, M. Glazov, L. Ivchenko, P. Zhou, G. Wang, T. Mano, N. Ha, T. Kuroda, Xavier Marie, K. Sakoda, B. Urbaszek, « Magnetospectroscopy of excited states in charge-tunable GaAs/AlGaAs [111] quantum dots  », Physical Review B : Condensed Matter and Materials Physics (1998-2015), juin 2016. ISSN 1098-0121

Abstract

We present a combined experimental and theoretical study of highly charged and excited electron-hole complexes in strain-free (111) GaAs/AlGaAs quantum dots grown by droplet epitaxy. We address the complexes with one of the charge carriers residing in the excited state, namely, the “hot” trions X−* and X+*, and the doubly negatively charged exciton X2−. Our magnetophotoluminescence experiments performed on single quantum dots in the Faraday geometry uncover characteristic emission patterns for each excited electron-hole complex, which are very different from the photoluminescence spectra observed in (001)-grown quantum dots. We present a detailed theory of the fine structure and magnetophotoluminescence spectra of X−*,X+*, and X2− complexes, governed by the interplay between the electron-hole Coulomb exchange interaction and the heavy-hole mixing, characteristic for these quantum dots with a trigonal symmetry. Comparison between experiment and theory allows for precise charge state identification, as well as extraction of electron-hole exchange interaction constants and g factors for the charge carriers occupying excited states.

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