Microstructure of Visible Light Emitting Porous Silicon

Abstract

The relationship between the microstructure and photoluminescence of porous Si is investigated. High-resolution scanning electron microscopy shows that porous Si has a small-particle structure, with particle sizes ranging from several nm to several tens of nm. Transmission electron microscopy shows that these particles are composed of single-crystal Si spheres covered with an oxide layer. Porous Si with larger particles emits light with longer wavelengths. This suggests that the effective photoluminescence of porous Si is due to three-dimensional carrier confinement in quantum boxes.