Time-correlated single-photon counting study of multiple photoluminescence lifetime components of silicon nanoclusters

► We report time-resolved PL measurements of Si-Ncs embedded in SiO2 matrix. ► Net decrease of PL with increasing the annealing temperature has been observed. ► Lifetime distribution analysis revealed a multiexponential decay with ns and ps components. ► Ps components are consistent with the lifetime range of the Auger recombination times. ► No evidence for a fast direct transition at the Brillouin zone centre.