Resonant and polarized Raman scattering from single CdS/CdSe core-shell nanowires

We report Raman scattering results on single CdS/CdSe core-shell nanowires (NWs). Under resonance excitation, optical phonons of either the CdS core or the CdSe shell are selectively enhanced. Polarization-resolved Raman scattering reveals that a longitudinal optical phonon response shows a maximum when the incident laser polarization is parallel to the scattered polarization. Interestingly, an additional phonon mode is observed at 194 cm^-1 when the scattered polarization is parallel to the NW long axis. We present evidence that this phonon response corresponds to the interface optical phonon localized at the core-shell interface.