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Proceedings Paper

Radial pressure measurement in core/shell nanocrystals
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Paper Abstract

Quantum dots are nanometre-sized semiconductor particles exhibiting unique size-dependent electronic properties. In order to passivate the nanocrystals surface and to protect them from oxidation, we grow a shell composed of a second semiconductor with a larger bandgap on the core (for example a core / shell CdS / ZnS). However, the lattice mismatch between the two materials (typically 7% between ZnS and CdS) induces mechanical stress which can lead to dislocations. To better understand these mechanisms, it is important to be able to measure the pressure induced on the semiconductor core. We used a nanocrystal doped with manganese ions Mn2+, which provide a phosphorescence signal depending on the local pressure. A few dopant atoms per nanoparticle were placed at controlled radial positions in a ZnS shell formed layer by layer. The experimental pressure measurements are in very good agreement with a simple spherically symmetric elastic continuum model[1]. Using manganese as a pressure gauge could be used to better understand some structural phenomena observed in these nanocrystals, such as crystalline phases transition, or shell cracking.

Paper Details

Date Published: 3 March 2009
PDF: 9 pages
Proc. SPIE 7189, Colloidal Quantum Dots for Biomedical Applications IV, 718908 (3 March 2009); doi: 10.1117/12.809965
Show Author Affiliations
Sandrine Ithurria, Lab. Photons Et Matière, CNRS, Ecole Supérieure de Physique et de Chimie Industrielles (France)
Philippe Guyot-Sionnest, The Univ.of Chicago (United States)
Benoît Mahler, Lab. Photons Et Matière, CNRS, Ecole Supérieure de Physique et de Chimie Industrielles (France)
Benoît Dubertret, Lab. Photons Et Matière, CNRS, Ecole Supérieure de Physique et de Chimie Industrielles (France)


Published in SPIE Proceedings Vol. 7189:
Colloidal Quantum Dots for Biomedical Applications IV
Marek Osinski; Thomas M. Jovin; Kenji Yamamoto, Editor(s)

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