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HL: Halbleiterphysik

HL 9: Poster I

HL 9.28: Poster

Montag, 27. März 2006, 15:15–17:45, P3

Synthesis and Characterisation of CdSe:Mn-nanoparticles — •Andreas Hofmann¹, Christina Graf¹, Reinhard Neder², Georg Schmidt³, and Eckart Rühl¹ — ¹Institut für Physikalische Chemie, Universität, , Am Hubland, D-97074 — ²Institut für Mineralogie und Kristallstrukturlehre, Universität Würzburg, Am Hubland, D-97074 — ³Physikalisches Institut, Universität Würzburg, Am Hubland, D-97074

We present a new preparation method for dilute magnetic II-VI-semiconductor nanoparticles by a high temperature synthesis. On the basis of a Green Chemistry approach we use CdO and different Mn-precursors to build up nearly monodisperse CdSe:Mn-nanocrystals (NC) without a size-selection process. The NC have a manganese content of about 1%, which was measured by ICP. SQUID-measurements also show a paramagnetic coupling, which indicates that there is no interaction between Mn-atoms. The size of the NC (3 to 7 nm) was determined by transmission electron microscopy and photoluminescence-measurements. We use EPR-spectroscopy to determine the location of Mn in the particles. It is shown that Mn is embedded in the CdSe-core. It is crucial for integrating Mn in the core of the NC that it has a zinc-blende lattice [1]. This is accomplished by growing CdSe on zinc-blende ZnSe NC. However, we use a novel synthesis [2] to produce zinc-blende CdSe-cores, where Mn can incorporate easily. Further, we try to coat the particles with a thin ZnS-shell and discuss resulting changes in fluorescence quantum yield.

[1] S. C. Erwin et al., Nature, 91, 436, (2005).

[2] M. B. Mohamed et al., J. Phys. Chem. B, 10533, 109, (2005).