Phonon-assisted optical transitions in spherical nanocrystals

Abstract

In order to interpret the photoluminescence spectra of spherical nanocrystals with zincblende structure, the intensities of phonon satellites are analyzed taking into account both the internal non-adiabaticity of the exciton-phonon system (the proper Jahn-Teller effect) and the external non-adiabaticity (the pseudo-Jahn-Teller effect). The effects of non-adiabaticity are shown to lead to a significant enhancement of phonon-assisted transition probabilities and to a more complicated dependence of these probabilities on the number of emitted or absorbed phonons in comparison with the results of adiabatic theory. The calculated relative intensities of the phonon satellites compare well with the experimental data on the photoluminescence of the CdSe spherical nanocrystals.