An experimental study of the temperature dependence of photoluminescence time decay in size-controlled silicon nanocrystals in silicon nanocrystal/SiO2 superlattices is reported. The samples were prepared using thermal evaporation and subsequent thermally induced phase separation.
The slow (microseconds) decay line shape is described well by a stretched exponential. The temperature dependence of the photoluminescence dynamics can be understood in terms of thermal activation of recombination processes, including hopping of carriers between localized states.
Additional hydrogen treatment causes an increase in both parameters of the stretched exponential function. This behavior is interpreted as a consequence of H-2-passivation of dangling bonds defects.