On the origin of photoluminescence in spark-eroded (porous) silicon

Abstract

Photoluminescence measurements and high-resolution transmission electron microscopy studies on spark-treated (porous) silicon have been performed. Contrary to suggestions put forward by others, it has been found that spark erosion does not yield structures comparable to those obtained for irradiated, that is, damaged silica. Instead, evidence is given that spark treatment of single crystalline silicon wafers produces randomly oriented nanometer-sized silicon crystallites surrounded by a SiO2 matrix. This configuration is believed to be responsible for the observed room temperature visible photoluminescence.