Visible photoluminescence of silicon-based nanostructures: Porous silicon and small silicon-based clusters

We have studied and compared the optical properties of both porous Si and the chemically synthesized planar and cubic Si skeleton clusters. Broad photoluminescence with large Stokes shifts were observed at the visible region in both samples. Spectroscopic analysis suggests that the surface of porous Si is similar to a condensation of Si clusters. Small Si clusters play a key role in the strong room-temperature photoluminescence in porous Si