Sustained photoluminescence of porous silicon is enhanced by efficient oxidation with a stable and moderate tris buffer solution

In this paper, we report a moderate and efficient method for the oxidation of porous silicon micro-particles (pSiMPs). The oxidation reaction was controlled by using a moderate Tris-buffer (25 mM) as the oxidant and citric acid solution as the terminator. The physical and chemical properties of pSiMPs before and after reaction have been characterized using photoluminescence, scanning electron microscope, Fourier transform infrared and Raman spectroscopy. And the mechanism of the oxidation of porous silicon and the termination reaction by adding acid was explored. The pSiMPs with good stability and photoluminescence properties can obtained by introducing 405 nm laser irradiation during the oxidation process, the ratio of oxidant volume and pSiMPs mass was 3:1, and controlling the oxidation process by 25 mM citric acid solution. Furthermore, specific concentration of citric acid can effectively improve the photoluminescence property of porous silicon.