Light Emission from Microcrystalline Si Confined in SiO₂ Matrix through Partial Oxidation of Anodized Porous Silicon

Abstract

Optical properties of microcrystalline Si embedded in a SiO 2 matrix through a partial oxidation of anodized porous silicon using a wet process have been studied. Thick (∼30 µm) films thus obtained were dark red to light yellow in color, depending on the oxidation condition. The fundamental edge of the absorption spectra shifted to the higher energy side with increasing oxide fractions in the colored specimen. Visible light emissions from these specimens were observed at room temperature with photoexcitations using a He-Cd laser. All of the data, including the broadening effect in X-ray diffraction peaks, can be explained in terms of the size reduction effect of the Si islands confined in the SiO 2 matrix.