Dresden 2014 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 30: Poster: Quantum dots and wires: Preparation, characterization, optical properties and transport

HL 30.10: Poster

Monday, March 31, 2014, 17:00–20:00, P2

A New Structure for Time-Resolved Transport Spectroscopy of InAs-Quantum Dots — •Sergej Markmann, Patrick A. Labud, Arne Ludwig, Dirk Reuter, and Andreas D. Wieck — Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum

Time-Resolved Transport Spectroscopy (TRTS) is a powerful method for the electrical investigation of Quantum Dots (QDs) and provides an access to the equilibrium and the non-equilibrium electron configurations in QDs. Typically the investigation of QDs with TRTS method is done on High Electron Mobility Transistor Structure in which QDs are embedded[1]. In this case, a time resolved conductivity change of the two-dimensional electron gas is an indicator for the charge configuration in the QDs. In this work, we demonstrate a new structure, which could be even more sensitive to charging and discharging events of the QDs. The new structure consists of p+-doped GaAs layer followed by an intrinsic GaAs layer in which InAs-QDs are embedded. On top of the intrinsic layer, a n+-doped GaAs layer is grown, which acts as a sensor for the QDs. Charging and discharging of QDs is controlled by the back-gate (p+-doped GaAs). With a top-gate, it is possible to deplete the channel (n+-doped GaAs layer) and hence control the conductivity of the channel such that the charged QDs may deplete the channel completely.

[1]B. Marquardt, M. Geller, B. Baxevanis, D. Pfannkuche, A. D. Wieck, D. Reuter and A. Lorke, Nature Commun. 2, 209 (2011).