Interrelation between Light Emitting and Structural Properties of Si Nanoclusters Embedded in SiO2 and Al2O3 Hosts

International audienceThe present work deals with the comparative investigation of Si-ncs embedded in SiO2 and Al2O3 dielectrics grown by RF magnetron sputtering on fused quarts substrate. The effect of post-deposition processing on the evolution of microstructure of the films and their optic and luminescent properties was investigated. It was observed that photoluminescence (PL) spectra of Six(SiO2)1-x films showed one PL band, which peak position shifts from 860 nm to 700 nm when the x decreases from 0.7 to 0.3. It is due to exciton recombination in Si-ncs. For Six(Al2O3)1-x films, several PL bands peaked at about 570-600 nm and 700-750 nm and near-infrared tail or band peaked at about 800 nm were found. Two first PL bands were ascribed to different oxygen-deficient defects of oxide host, whereas near-infrared PL component is due to exciton recombination in Si-ncs. The comparison of both types of the samples showed that the main radiative recombination channel in Six(SiO2)1-x films is exciton recombination in Si-ncs, while in Six(Al2O3)1-x films the recombination via defects prevails due to higher amount of interface defects in the Six(Al2O3)1-x caused by stresses