Improvement of the Photoluminescence of Porous Si Powder via Oxidation in Organic Solvents

Abstract

We studied the photoluminescence (PL) of porous Si powder via oxidation in distilled water and organic solvents of ethanol, acetone and hexane. Porous Si powder aged in an ethanol solution increased in PL intensity up to 50 times over 4 days. Even though the PL intensity of porous Si aged in acetone and hexane solutions also increased, the increase was smaller than that of seen in the ethanol solution. Porous Si powder oxidized in an ethanol solution shows the best improvement in PL intensity for all the used solvents. However, the PL intensity of porous Si aged in distilled water decreased. The PL intensity of porous Si aged in deaerated ethanol slowly increased indicating that the surface oxidation of porous Si was caused by the oxygen dissolved in the organic solvents. Oxidation of a porous Si surface strongly depends on the type of organic solvent.