Resonant Raman scattering by CdTe quantum-well-confined optical phonons in a semiconductor microcavity
Résumé
We present a Raman scattering study of CdTe quantum well (QW) optical phonons in a II-VI semiconductor microcavity. These have been performed under outgoing resonance conditions with the cavity polaritons. The CdTe optical phonon spectra show a main peak and smaller oscillationlike features towards lower phonon energies, which are assigned to QW confined phonons. The fact that the oscillations are found to be equidistant, thus leading to an almost linear effective dispersion for the confined phonons, is attributed to segregation and interdiffusion of atoms at the QW interfaces providing a rather parabolic-shaped phonon-confining potential. An ``effective-mass'' model is used to describe the optical phonon confinement, leading to microscopic information on the compositional profile of the QW's embedded within the optical cavity.