Resonant Raman scattering on optical phonons confined in spherical semiconductor nanocrystals: ODP interaction and polaron effects

Theoretical and experimental results concerning Raman-active optical phonon modes and exciton-phonon (e-ph) interaction in nearly spherical nanocrystals (NC's) of II-VI and III-V semiconductors are presented. A continuum lattice dynamics model for confined phonons and the effective mass approximation for electronic states in the NC's were used in the calculations. Both Fröhlich and optical deformation potential (ODP) mechanisms of the e-ph interaction were considered. Based on the computed e-ph interaction constants, Raman spectra have been calculated within standard perturbation theory and polaron approaches. The experimental studies were performed on NC films fabricated using wet chemistry methods. The results, as well as those obtained for other NC systems, published in the literature, are in good agreement with the theoretical predictions. © 2007 American Institute of Physics.