Dresden 2009 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 7: Semiconductor substrates

O 7.7: Vortrag

Montag, 23. März 2009, 12:45–13:00, SCH A315

Structural properties of the InAs/GaAs system before and after quantum dot formation. — •Britta Höpfner, Christopher Prohl, Jan Grabowski, Holger Eisele, and Mario Dähne — Institute of Solid State Physics, Technical University Berlin, Germany

The structure of the wetting layer prior to quantum dot formation and the shape of just formed quantum dots are of high interest for the understanding of the quantum dot growth mechanisms. To understand growth and properties of InAs layers on GaAs step by step a molecular-beam epitaxy-system (MBE) including reflection high energy electron diffraction (RHEED) and attached scanning-tunneling microscope (STM) was used. In this work, GaAs(001) surfaces covered with increasing InAs coverages beginning with about one monolayer up to the formation of quantum dots were prepared. In order to study the influence of the surface reconstruction on the growth, both As-rich GaAs(001) c(4x4) and β2(2x4) reconstructed surfaces were used. Atomically resolved STM images of different coverages and an analysis of the growth behavior will be presented. Structural changes during closing of the first monolayer will be shown.

The authors thank K. Jacobi and the MPG for providing the experimental set-up. The work was supported by project Da 408/12 of the DFG.