Berlin 2008 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 31: Poster II

HL 31.27: Poster

Dienstag, 26. Februar 2008, 16:30–19:00, Poster D

Growth and faceting of self-assembled GaAs quantum dots — •Andrea Stemmann, Christian Heyn, Andreas Schramm, and Wolfgang Hansen — Universität Hamburg, Institut für Angewandte Physik, Jungiusstrasse 11, 20355 Hamburg

Strain-free GaAs quantum dots (QDs) are grown in a self-assembled fashion by applying Ga droplet epitaxy. Dependent on growth temperature and Ga flux, QDs with different size and density are grown. The QDs are studied using electron diffraction (RHEED) and atomic force microscopy. We find two distinct regimes for the QD shape. QDs whose volume exceeds approximately 3x10⁵ Ga atoms are shaped like truncated pyramids with side facets having an angle α of about 55^∘ corresponding to (111)-type side facets. Smaller QDs are pyramid like with α = 25^∘ and (113)-type facets.