Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 44: Poster Session: Quantum Dots and Wires - Transport & Optical Properties
HL 44.18: Poster
Dienstag, 27. März 2012, 09:30–12:30, Poster D
Optical properties of ultra-low density GaAs Quantum Dots — •Vera Paulava, David Sonnenberg, Andreas Graf, Christian Heyn, and Wolfgang Hansen — Institut für Angewandte Physik, Universität Hamburg, 20355 Hamburg, Germany
We study a novel type of GaAs quantum dots (QDs), which are formed by filling of self-assembled nanoholes in semiconductor surfaces. The holes were drilled using local droplet etching (LDE) during molecular beam epitaxy [1]. In our case, nanoholes are drilled into AlGaAs barrier material with Al droplets and subsequently filled with GaAs to form the quantum dots. The QD size can be precicesly controlled by the filling level. Here we present a study of the optical properties of such GaAs QDs with ultra-low densities of 6·106 cm−2. The low density of these dots is achieved without any lithographic or other ex-situ preparation steps, and allows clear single-dot photoluminesence studies of the excitonic states up to high excitation power by using a focused laser for excitation. Especially the exciton energies and the exciton-biexciton splittings are studied in dependence of the QD size.
[1] Heyn et al., Appl. Phys. Let. 94, 183113 (2009)