Berlin 2015 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 44: Quantum dots: Preparation and characterization

HL 44.4: Vortrag

Mittwoch, 18. März 2015, 10:15–10:30, EW 203

Localization of charge carriers in MOCVD-grown InAs(Sb)/GaAs sub-monolayer stacks — •D. Quandt, J.-H. Schulze, A. Schliwa, M. Gschrey, S. Rodt, Z. Diemer, C. Prohl, A. Lenz, H. Eisele, A. Strittmatter, U. W. Pohl, S. Reitzenstein, and D. Bimberg — Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstraße 36, D-10623 Berlin

Conventional growth of InAs/GaAs sub-monolayer stacks results in the formation of high density InAs islands with strong vertical electronic coupling. Additionally, lateral electronic coupling is possible for sufficiently large densities, resulting in weakened three-dimensional confinement of electrons and holes. The addition of Sb to the growth sequence results in a stronger localization of charge carriers, as shown by cathodoluminescence measurements, in which individual emission lines appear in the luminescence spectrum, and temperature-dependent photoluminescence measurements revealing an S-shape in the temperature-dependent peak energy position. 8-band k·p simulations have been utilized to investigate the influence of Sb on the wavefunctions of electrons and holes. The structural properties of the sub-monolayers have been investigated by cross-sectional scanning tunneling microscopy, showing a smaller size of the In agglomerations as compared to sub-monolayers grown without Sb as well as a slight clustering tendency of the Sb atoms.