Dresden 2014 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 78: Quantum dots: Preparation and characterization

HL 78.6: Talk

Wednesday, April 2, 2014, 17:45–18:00, POT 251

Charge carrier localization by Sb-assisted growth of InAs/GaAs sub-monolayer stacks — •David Quandt, Jan-Hindrik Schulze, Manuel Gschrey, Ronny Schmidt, Sven Rodt, Andre Strittmatter, Udo W. Pohl, and Dieter Bimberg — Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstraße 36, D-10623 Berlin

Quantum dots (QDs) grown in the sub-monolayer (SML) growth mode result in dense arrays of 3D charge carrier localization centers which enable high-gain active regions in laser devices. InAs/GaAsSML QDs grown by MOVPE typically exhibit very high island densities which, due to lateral electronic coupling, provide only weak carrier localization. Using Sb as additional species during growth of InAs/GaAs SML QDs, the electronic confinement properties can be effectively tuned to strong carrier localization. This is evidenced by spatially resolved cathodoluminescence spectroscopy revealing individual sharp lines in the ensemble luminescence. The amount of supplied Sb controls also the ensemble broadening which is very attractive for mode-locking applications in laser devices.