Size dependence of electron—LO-phonon coupling in semiconductor nanocrystals

An increase in the Fr\"ohlich-electron-LO-phonon interaction strength with decreasing nanocrystal size in the strong confinement limited is reported. This results from the size dependence of resonant Raman scattering by CdSₓSe_1-x nanocrystals embedded in a glass slab. The mean particle radius 20<R̄<30 {} increases monotonically with the position along the slab so that, for each laser line, the resonance has been tuned by scanning the sample with a microprobe. The relative strength between Fr\"ohlich and deformation-potential contributions is determined by analyzing the polarization properties of the scattering.