Oxidized silicon nanoclusters: a theoretical study.

Total energy calculations have been performed to understand the role of oxidation on the structural, electronic and optical properties of Si nanoclusters. Our aim is to explain the peculiar properties of aged porous Si samples, heavily oxidized Si nanoparticles and embedded Si nanocrystals. We have studied two types of structures: isolated H-covered clusters, replacing Si-H bonds with various Si-O bonds; and Si nanoclusters embedded in a SiO2 matrix. Regarding the isolated clusters we find that the optoelectronic properties depend on the type and the number of Si-O bonds at the cluster surface. For the embedded systems our results show that a close interplay between chemical and structural effects plays a key role in the light emission processes. SINGAPORE: World Scientific (SINGAPORE).