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HL: Halbleiterphysik

HL 31: Quantenpunkte und -dr
ähte: Herstellung und Charakterisierung

HL 31.10: Talk

Wednesday, March 26, 2003, 16:45–17:00, BEY/154

In situ site control of single quantum-dot structures using shadow masks — •T. Schallenberg¹, S. Rodt², T. Borzenko¹, R. Heitz², C. Schumacher¹, G. Schmidt¹, M. Obert¹, G. Bacher¹, D. Bimberg², G. Karczewski¹, and L. W. Molenkamp¹ — ¹Physikalisches Institut, EP III and TP, Universität Würzburg, D-97074 Würzburg — ²Institut für Festkörperphysik, TU Berlin, D-10623 Berlin

An effective method for controlling the position and number of self-assembled quantum dots (QDs) grown by molecular beam epitaxy (MBE) has been developed. Epitaxially grown shadow masks are used to realize selective area growth, which exploits different incidence angles of the molecular beams. We applied this method to control the position and number of self-assembled CdSe QDs in a ZnSe matrix. Bright cathodoluminescence shows the presence of regularly distributed ensembles of QDs and that single QDs can be reliably grown.

In addition, we have demonstrated the ability of this in situ technique to grow ZnCdSe quantum well islands selectively in the overlap area of the Cd and Se molecular beams, which are incident on the surface through different apertures of the shadow mask. The position, area, and shape of these islands can be precisely controlled by the shapes and the positions of the apertures in the mask and, in situ, by the incidence angles of the beams. This is done with a spatial precision of 20 nm. Finally, we demonstrate that this technique can be applied to control the doping and the incorporation of Mn in selected areas.

This work is supported by SFB 410 and SFB 296 of the DFG.