Visible photoluminescence from porous poly-Si/Si and amorphous-Si/Si structures

We performed visible photoluminescence and scanning electron micrograph mea surements on several porous poly-Si/Si and a-Si/Si structures. We found tha t the porous interfacial layer between the thin film and the substrate dete rmined the optoelectronic properties for the structures. With the results, we present a model for porous structures based on the quantum confinement e ffect in silicon wires; the decreasing emission intensity and the redshift of photoluminescence originate from the silicon wires in the porous interfa ce formed during all electrochemical process.