Dresden 2006 – scientific programme

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HL: Halbleiterphysik

HL 7: Quantum dots and wires: Optical properties I

HL 7.4: Talk

Monday, March 27, 2006, 11:00–11:15, POT 151

Optical Nearfield Spectroscopy of Individual InAs/GaAsQuantum Dots at Low Temperatures — •Omar Al-Khatib, Kai Hodeck, and Mario Dähne — Technische Universität Berlin, Institut fürFestkörperphysik, Hardenbergstr. 36, 10623 Berlin, Germany

Semiconductor quantum dots attract considerable interest for future technical purposes. In particular the possibility to realise discrete energy levels in solid-state matter promises to provide a basis for innovations like new laser sources or quantum information technology. We report on photoluminescence spectroscopy of individual MOCVD-grown InAs/GaAs-dots. For that purpose we use Scanning Nearfield Optical Microscopy (SNOM) in the range from 10 K up to 300 K [1]. We focus on the investigation of relatively large quantum-dots, which are grown with low dot density and display ground-state emission of 1300 nm wavelength at room-temperature, thus matching telecommunication fiberoptic requirements. By taking single-dot spectra under varying excitation intensity, we observe photoluminescence emissions from different recombination processes, in particular biexciton and trion recombination, and discuss the data with theoretical models of multiexciton complexes. We would like to thank Konstantin Pötschke and Prof. Dr. D. Bimberg for providing the samples.

[1] K. Hodeck et al., phys. stat. sol. (c)No.4, 1209 (2003)