Berlin 2012 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 5: Quantum Dots and Wires: Preparation and Characterization I

HL 5.6: Vortrag

Montag, 26. März 2012, 10:45–11:00, EW 202

Raman study of zinc blende and wurtzite CdSe/CdS heteronanocrystals — •Amelie Biermann¹, Raquel Gomes², Holger Lange¹, Zeger Hens², and Christian Thomsen¹ — ¹TU Berlin, Institut für Festkörperphysik, EW5-4, 10623 Berlin, Germany — ²University of Ghent, Physics and Chemistry of Nanostructures, Krijgslaan 281-S3, Ghent, B-9000, Belgium

CdSe based heteronanocrystals offer a wide range of potential applications in the field of optoelectronics. Especially colloidal CdSe-CdS core-shell nanocrystals are currently of high interest because they offer new technics of application, e.g. printing of devices from a solution. The possibility to synthesize defined nanocrystals with a precise control over their size enables the use in systems like biological sensors, LEDs, lasers and solar cells.

The magnitude of the coupling of excited carriers to phonons in the CdSe core contributes to the time scales of different photophysical processes of high significance for those applications. These processes include for example carrier multiplication rates, and relaxation times and are strongly influenced by the states in the interface region of core and shell. In our contribution we present a systematic Raman study of wurtzite and zinc blende CdSe/CdS core-shell structures, revealing the structural details of the sample as well as the exciton-phonon coupling strength via the Huang-Rhys factor.