Semiconductor Cd(S, Se) quantum dots in glasses: Size determination by low-frequency Raman scattering

Room-temperature Stokes and anti-Stokes Raman scattering spectra have been measured in the low-energy acoustic and high-energy optical phonon region for Cd(S, Se)-doped glasses. The peaks observed in the low-frequency region were assigned to the confined acoustic eigenmodes of II-VI semiconductor nanoparticles embedded in an amorphous matrix. The size dependence of the acoustic peak positions and the relation between the size distribution and bandwidth of these peaks was derived. The size-dependent changes in the region of CdS longitudinal-optical modes were attributed to the confinement of phonons in a small nanocrystal volume.