Dresden 2006 – scientific programme
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HL: Halbleiterphysik
HL 56: Quantum dots and wires: Preparation and characterization III
HL 56.9: Talk
Friday, March 31, 2006, 13:00–13:15, POT 51
Atomic structure of unstrained GaAs/AlGaAs quantum dots — •Andrea Lenz1, Rainer Timm1, Lena Ivanova1, Dominik Martin1, Vivien Vossebürger1, Holger Eisele1, Armando Rastelli2, Oliver Schmidt2, and Mario Dähne1 — 1Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstr. 36, 10623 Berlin, Germany — 2Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, 70569 Stuttgart, Germany
GaAs/AlGaAs quantum dots (QD), formed by a combination of self-assembled growth and atomic-layer etching technique, are a novel and promising structure [1]:
The material is ideally unstrained and can be designed to emit light in the optical spectral range. For improving the epitaxial growth a detailed knowledge of the interfaces and the quantum dot structure after overgrowth is essential.
Cross-sectional scanning tunneling microscopy (XSTM) is a powerful method to investigate the shape and size of buried semiconductor nanostructures with atomically resolution. We present XSTM images of the GaAs/AlGaAs interface and of the inverted quantum dot structures, indicating that the unstrained QDs have a truncated cone shape and a relatively large base length of about 35 nm.
Thereby the growth model [1] can be confirmed.
This work was supported by the EU in the SANDiE Network of Excellence and by SFB 296 of the DFG.
[1] A. Rastelli, S. Stufler, A. Schliwa, R. Songmuang, C. Manzano, G. Costantini, K. Kern, A. Zrenner, D. Bimberg, and O. G. Schmidt, Phys. Rev. Lett. 92, 166104 (2004)