Dresden 2006 – scientific programme

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HL: Halbleiterphysik

HL 50: Poster II

HL 50.87: Poster

Thursday, March 30, 2006, 16:30–19:00, P3

Multiphonon Raman scattering of spherical PbSe quantum dots — •J. T. Devreese^1,2, S. N. Klimin^1,3, V. M. Fomin^1,2,3, and F. W. Wise⁴ — ¹TFVS, Universiteit Antwerpen, B-2610 Antwerpen, Belgium — ²Department of Semiconductor Physics, TU Eindhoven, NL-5600 MB Eindhoven, The Netherlands — ³State University of Moldova, Kishinev, Republic of Moldova — ⁴Department of Applied Physics, Cornell University, Ithaca, New York 14853, USA

Multi-phonon resonant Raman scattering in spherical PbSe quantum dots is investigated using a non-adiabatic approach. The optical phonons in quantum dots are treated within the multimode dielectric continuum model, taking into account both the electrostatic and mechanical boundary conditions for the relative ionic displacement. The exciton-phonon interaction is considered for all phonon modes specific for these quantum dots. Our multimode dielectric continuum model, which includes, as a substantial ingredient, the realistic dispersion of optical phonons, adequately describes the optical-phonon spectra of spherical PbSe quantum dots. The non-adiabaticity leads to a substantial enhancement of the relative intensities of multi-phonon peaks with respect to the intensity of the one-phonon peak. The peak positions and intensities of the calculated Raman scattering spectra for spherical PbSe quantum dots are in good agreement with recent experimental results on the Raman scattering in oleic-acid-capped colloidal PbSe nanocrystals.

This work was supported by the GOA BOF UA 2000, IUAP, FWO-V projects G.0274.01N, G.0435.03 and the WOG WO.035.04N (Belgium).