Photoinduced luminescence enhancement from anodically oxidized porous Si

Abstract

We have investigated the phenomenon of photoluminescence (PL) increase in anodically oxidized porous Si with increasing laser illumination time by transmission Fourier transform infrared spectroscopy (FTIR), PL spectroscopy, and electron paramagnetic resonance. The adsorption of oxygen without hydrogen loss was observed during laser illumination by FTIR. The PL intensity increased linearly, while the dangling bond (DB) density decreased with increasing illumination time. By assuming that the decrease of DB density has a linear response to the illumination time, we identify that the change in DB density is mainly responsible for the observed PL increase after laser illumination.