Interface Phonons in CdSe/ZnSe Self-Assembled Quantum Dot Structures

We use micro-Raman scattering to study the interface (IF) optical phonon in a CdSe self-assembled quantum dot structure. Spatially resolved micro-Raman scattering data obtained from a cleaved edge of a sample shows that the IF phonon is localized at the CdSe dot layer. The intensity of the Raman scattering from the IF phonon strongly increases as the CdSe dots are excited resonantly, suggesting strong coupling of the IF phonon to excitons localized in the CdSe dots. Intensity changes of the IF phonon as a function of excitation energy reflect an energy level distribution within the ensemble of CdSe dots. We suggest that the IF phonon plays a role in the phonon-related carrier relaxation process in the CdSe self-assembled quantum dot structures.