Correlation between photoluminescence properties and morphology of laser-ablated Si/SiOx nanostructured films

Pulsed laser ablation in an inert gas has been used to fabricate films containing silicon nanocrystals. We show that film microstructure is one of the main factors, determining long-term photoluminescence (PL) properties. Films with different porosity were found to exhibit PL signals with quite different peak energies, integral intensities and time-dependent evolutions. The distinction of these PL properties is attributed to the different efficiency of surface chemistry interactions between Si nanocrystallites and the ambient atmosphere for films having different porosities. Oxygen-related defects and other mechanisms are discussed to explain the PL properties of the films.