Observation of non-radiative de-excitation processes in silicon nanocrystals

We describe the impact of non‐radiative de‐excitation mechanisms on the optical emission from silicon nanocrystals formed in SiO2. Auger excitation via free carriers deliberately introduced through phosphorus ion implantation, shows a monotonic increase with increasing phosphorus concentration which can be modelled adequately using a simple statistical approach. We also report a reduction in nanocrystal luminescence intensity with increasing exposure to UV radiation and suggest this phenomenon results from the introduction of non‐radiative defects in the Si/SiO2 network. The effect of UV radiation varies significantly depending on the sample preparation. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)