Regensburg 2007 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 13: Poster 1
HL 13.46: Poster
Montag, 26. März 2007, 15:00–17:30, Poster A
Photoluminescence Spectroscopy of CdSe/CdS(/ZnS) Quantum Dots — •Torben Menke1, Gerwin Chilla1, Marija Nikolic3, Andreas Frömsdorf2, Tobias Kipp1, Detlef Heitmann1, Horst Weller2, and Sephan Förster2 — 1Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg, Jungiusstraße 11, 20355 Hamburg — 2Institut für Physikalische Chemie, Universität Hamburg, Grindelallee 117, 20146 Hamburg — 3Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia
We investigate chemically synthesized nanocrystal quantum dots by photoluminescence (PL) spectroscopy. Our CdSe-core nanocrystals, fabricated as core-shell and core-shell-shell variants, are embedded in a thin polymer matrix on silicon substrates or spin coated directly on sapphire substrates. The nanocrystal density on the substrate is chosen to be so low, that both, ensemble and single nanocrystal PL experiments are possible. In our ensemble measurements, we have in particular studied the photostability of the photoluminescence signal for temperatures T=4-300K and for different excitation densities. We found the expected red-shift of the photoluminescence with increasing temperature and indication for a high stability of the photon efficiency. In microscopic photoluminescence measurements on single nanocrystals we found crystals with an impressive stability concerning photobleaching. The blinking behavior shows that these nanocrystals are predominantly in the on-state. We acknowledge financial support by the Deutsche Forschungsgemeinschaft via the SFB 508.