Dresden 2014 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 4: Physics of quantum rings (Focus session with TT)

HL 4.3: Topical Talk

Monday, March 31, 2014, 10:45–11:15, POT 151

Self-organized formation and XSTM characterization of GaSb/GaAs quantum rings — •Andrea Lenz — Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany

In the GaSb/GaAs material system, quantum rings (QRs) can occur already after the material deposition on GaAs(001), sometimes even without capping. Upon capping almost all quantum dots are transformed into QRs [1].

This presentation gives an overview of the structural parameters and the formation process of the GaSb/GaAs QRs using cross-sectional scanning tunneling microscopy (XSTM). Furthermore, information on the electronic structure of the QRs is shown, which is gained using scanning tunneling spectroscopy mode (XSTS). XSTS reveals the type-II alignment for GaSb/GaAs QRs [2], which makes them very promising for charge storage devices and in photovoltaics. Furthermore, the GaSb/GaAs system exhibits a strong Aharonov-Bohm effect since the central opening of the QRs is much more pronounced as compared with other material systems, like e.g. the InGaAs/GaP system, for which QRs have been observed quite recently [3].

This work was supported by the EC through the SANDiE NoE and by projects Da 408/13 and Sfb 787 of the DFG.

[1] A. Lenz and H. Eisele, in: V. M. Fomin (Ed.), Physics of Quantum Rings, Springer, Berlin-Heidelberg, 2014, pp. 123-142. [2] R. Timm et al., Nano Lett. 10, 3972 (2010). [3] C. Prohl et al., Appl. Phys. Lett. 102, 123102 (2013).