Size effects on the temporal dynamics of edge emission in CdSe microcrystals embedded in a germanate glass matrix

Picosecond time-resolved spectra of edge emissions in CdSe microcrystals with various sizes grown in a germanate glassy matrix are measured at 80 K. The temporal behavior of the edge emission exhibits multiexponential decay depending on the size of the crystal. The deconvolution analysis results in three decay components (F,S₁,S₂) that have different characters. The size dependence found in the decay time of the component S₁ agrees with a calculated dependence for the radiative lifetime of squeezed excitons. The component F with a decay time of about 20 ps originates from interactions of free carriers with trapped carriers.