Photoluminescence of Er silicates on microstructured Si substrate

Large amounts of Er silicates were fabricated on microstructure Si substrates by spin-coating of ErCl3/ethanol solutions and post-thermal processing techniques. Preoxidation of the substrate enhances the formation of Er silicates (Er2Si2O7, Er2SiO5), particularly the portion of Er2Si2O7. The Er silicates fully cover the microstructured substrate, showing no granular morphologies. Very narrow XRD peaks also suggest large grain size of the Er silicate crystals. As-fabricated samples show strong photoluminescence (PL) at room temperature around 1530 nm. The PL intensity is shown to be largely dependent on the conditions of preoxidation, annealing temperature and time, while the decay time is defect-limited, and mainly dependent on the annealing conditions rather than the preoxidation. We suggest that Er silicates can thus be incorporated into ordered Si microstructures, such as photonic crystals, to develop more functional light emitting devices.