Resonant Raman scattering in spherical quantum dots: II-VI versus III-V semiconductor nanocrystals

Resonant Raman scattering (RRS) in nearly-spherical nanocrystal (NC) quantum dots (QDs) is discussed with respect to the underlying (Frohlich-type and optical deformation potential, ODP) mechanisms of the exciton-phonon interaction. Their relative contribution for different QD materials, both II-VI and III-V is compared. It is shown that the (usually overlooked) ODP interaction is entirely responsible for an additional peak in the RRS spectra, situated near the transverse-optical (TO) phonon frequency, which has been observed for InP, InAs and, recently, CdTe QDs. RRS spectra calculated using continuum models for confined phonons and excitons and taking into account both interaction mechanisms are in excellent agreement with these experimental data. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim