Photoluminescence quantum yield in ensembles of Si nanocrystals

This study investigates the photoluminescence quantum yield for co-sputtered solid-state dispersions of Si nanocrystals in SiO₂ with different size and density, and concludes that the absolute value of the photoluminescence quantum yield shows a varied dependence on the excitation energy. Physical mechanisms influencing the photoluminescence quantum yield at different excitation energy ranges are considered. Based on the experimental evidence, this study proposes a generalized description of the excitation dependence of photoluminescence quantum yield of Si nanocrystals in SiO₂, and concludes on the important role of impact excitation by hot carriers and parasitic absorption at high and low excitation energy ranges, respectively.