Berlin 2008 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 43: Quantum dots and wires: Optical properties II
HL 43.2: Vortrag
Donnerstag, 28. Februar 2008, 14:15–14:30, EW 201
Optical QD properties as quantitative fingerprints of structural and chemical properties — •Andrei Schliwa1, Robert Seguin2, Sven Rodt2, Momme Winkelnkemper2, Dieter Bimberg2, Thomas Hammerschmidt3, and Peter Kratzer4 — 1WIAS Berlin — 2TU-Berlin, Institut für Festkörperphysik — 3University of Oxford — 4Universität Duisburg-Essen
The detailed shape and composition of capped quantum dots (QD), which present the decisive input parameters for all device modeling, are difficult to determine directly. Spectroscopic data can, however, serve as fingerprints for a specific QD structure. Thus, addressing the inverse problem of fitting spectroscopic data to a detailed theoretical model leads to the determination of size, shape and composition as adjustable parameters.
Single-particle states were obtained by eight-band k*p theory, taking into account arbitrary QD-shapes, strain (using atomistic- as well as continuum mechanical models), piezoelectricity (first- and second order). The energies of few-particle states (exciton, biexciton, charged excitons) are calculated using the configuration interaction approach, thus, accounting for direct Coulomb effects, exchange and correlation. We will present systematic calculations of many types of QDs, varying size, shape, and composition.
To demonstrate the power of our approach, results of modeling are compared to single QD cathodoluminescence spectra tracing the evolution of one and the same QD over several steps of annealing.