Dresden 2009 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 39: Quantum dots: Optical and transport properties

HL 39.8: Talk

Thursday, March 26, 2009, 11:30–11:45, BEY 81

Coulomb blockade due to lithographically aligned InAs quantum dots in GaAs/AlGaAs constrictions — •Sebastian Göpfert, Lukas Worschech, Daniela Spanheimer, Christian Schneider, Monika Emmerling, Sven Höfling, and Alfred Forchel — Technische Physik, Universität Würzburg, 97074 Würzburg

By combination of site-controlled growth of InAs quantum dots with an accurate alignment to narrow constrictions defined in a modulation doped GaAs/AlGaAs heterostructures quantum dots with large Coulomb energies were realized. For that purpose, modulation doped GaAs/AlGaAs heteterostructures were grown by molecular beam epitaxy. The position of the InAs quantum dots was controlled by defining nanoholes as nucleation centers ^1,2. After regrowth with InAs and a capping, narrow constrictions were etched relative to the site-controlled quantum dots with a position accuracy of 50 nm. The site-controlled InAs quantum dots serve as floating gate, and define electronic quantum dots in the narrow channel. By means of transport measurements single-electron addition energies in the order of 10 meV were observed.
[1]Lateral Alignment of Epitaxial Quantum Dots, edited by O. G. Schmidt, Springer, Berlin, 2007.

[2]C. Schneider, M. Strauß, T. Sünner, A. Huggenberger, D. Wiener, S. Reitzenstein, M. Kamp, S. Höfling, A. Forchel, Appl. Phys. Lett. 92, 183101 (2008).