Novel processing for Si-nanocrystal based photonic materials

We report a study of novel processing approaches for the formation of silicon nanocrystals for photonic devices. A silicon rich oxide was formed using ion implantation into thermally grown oxides on Silicon and transparent sapphire substrates. These layers were then treated with rapid thermal processing to observe the formation of silicon nanocrystals on a one second to ten minute timescale. Transmission electron microscopy and Raman scattering were used to follow the evolution of the nanocrystal mean diameter with anneal time. Identical samples co-implanted with Erbium demonstrated the widely reported non-resonant energy transfer mechanism from the nanocrystals to the internal energy levels of the erbium. We quantified the sensitization efficiency, I _Er/I_nc as a function of the Si-NC size by correcting the relative visible and IR luminescence intensities for variations in the nanocrystal density and observed photoluminescence lifetime. We find that the sensitizing efficiency increases exponentially with decreasing Si-NC mean diameter.