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