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Optical characterization of hierarchically self-assembled GaAs/AlGaAs quantum dots

Published online by Cambridge University Press:  26 February 2011

F. Marabelli
Affiliation:
CNR-INFM Pavia and University of Pavia, via Bassi 6, I-27100 Pavia, Italy
A. Rastelli
Affiliation:
Max-Plank-Institut fur Festkorperforschung, Heisembergstr. 1, D-70569 Stuttgart, Germany
O. G. Schmidt
Affiliation:
Max-Plank-Institut fur Festkorperforschung, Heisembergstr. 1, D-70569 Stuttgart, Germany
G. Beaurin
Affiliation:
CNR-INFM Pavia and University of Pavia, via Bassi 6, I-27100 Pavia, Italy
M. Geddo
Affiliation:
CNR-INFM Pavia and University of Parma, v. delle Scienze 7, I-43100 Parma, Italy
G. Guizzetti
Affiliation:
CNR-INFM Pavia and University of Pavia, via Bassi 6, I-27100 Pavia, Italy
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Abstract

Recently, a simple method has been developed to obtain inverted GaAs/AlGaAs quantum dots (QDs) below a quantum well (QW) via multi-step (hierarchical) self-assembly [1]. Here we report on the optical characterization of a series of structures GaAs QDs with different size. The study is performed by means of reflectance (R) down to T=15 K, photo- and thermo-reflectance (T>80 K) and by spectroscopic ellipsometry (at RT). Such measurements allow us to check the thickness and composition of the barrier layers and to complete the study of the electronic states involved in the emission properties of QDs and QW levels. QW states were well identified and their energies and shift with the size parameters well agree with the photoluminescence (PL) data. The identification of QD states seems less straightforward in R measurements and deserves further investigation.

Type
Research Article
Copyright
Copyright © Materials Research Society 2005

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References

1 Rastelli, A. et al., Phys. Rev. Lett. 92, 166104 (2004).Google Scholar
2 Denker, U., Stoffel, M., and Schmidt, O.G., Phys. Rev. Lett. 90, 196102 (2003).Google Scholar
3 Songmuang, R., Kiravittaya, S., and Schmidt, O.G., Appl. Phys. Lett. 82, 2892 (2003).Google Scholar
4 Kiravittaya, S. et al., J. Cryst. Growth 251, 258 (2003).Google Scholar