Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 35: Poster I

HL 35.49: Poster

Dienstag, 8. März 2016, 15:00–19:00, Poster A

Emission wavelength tuning of InAs quantum dot molecules by rapid thermal annealing — •Alexander Karlisch, Nandlal Sharma, Stepan Shvarkov, and Dirk Reuter — Optoelektronische Materialien und Bauelemente, Universität Paderborn, Paderborn, Germany

Vertically stacked InAs quantum dots (QDs), so-called quantum dot molecules (QDM), have attracted much interest in the framework of solid state based quantum information processing. The realization of such applications require addressing a single QDM, e. g. by optical methods. To use effective, silicon based detectors and pump lasers that allow single QDM experiments, a ground state emission wavelength of around 950 nm at low temperatures is required. In this contribution, we present a study of emission wavelength tuning by rapid thermal annealing (RTA) for single layer QDs as well as QDM. The samples have been grown by solid-source molecular beam epitaxy on GaAs(100) substrates employing the Stranski-Krastanov growth mode. The as-grown samples show a ground state emission around 1150 nm at low temperatures. The samples have been annealed for 30 s at various temperatures under nitrogen gas atmosphere. To avoid As desorption during annealing, the samples were covered with pieces of a GaAs-wafer as proximity caps. Photoluminescence spectra showed that the emission wavelength at low temperatures could be blue-shifted below 950 nm for the single layer QDs as well as for the QDM while maintaining high luminescence intensities. We attribute the blue-shift to the interdiffusion of Ga and In. The influence of the annealing temperature is discussed in detail.