Reduced graphene oxide as a stabilizing layer for optical properties of porous silicon

In this paper, the intrinsic instability of optical properties of porous silicon (PS) was minimized by deposition of graphene on porous structures. A typical PS showed an obvious quenching of its photoluminescence (PL) properties under long-term laser radiation. To resolve this problem, graphene thin film was grown on the porous structure using electrophoretic deposition (EPD) technique. Here, eco-friendly improved Hummer's technique was used for synthesis of charged graphene oxide (GO) sheets. The synthesized high-dispersed GO suspension demonstrated good response in electrical field. For reducing process, in order to fabricate reduced graphene oxide (RGO), thermal annealing of samples was carried out at 100 °C under Ar ambient. The Raman studies confirmed that RGO layers have been deposited on PS substrates successfully. Compared with the PS sample, a reduction by 35% of photoluminescence (PL) intensity was observed for RGO/PS sample. This phenomenon can be explained by light absorption of 2.3% in each graphene layer. The effect of graphene as a stabilizing layer on PS substrate was observed in PL spectrum of RGO/PS sample. The PL quenching was arrested even after prolonged exposure to laser illumination. Therefore, the deposited graphene layer enhances the optical properties of PS by stabilizing the PL intensity.