Modification of the scattering of silver nanoparticles induced by Fabry–Pérot resonancesrising from a finite Si layer

Abstract

In this paper we theoretically give evidence of the enhancement of scattering phenomenarelated to single metal nanoparticles having different shapes and located on a siliconlayer having finite thickness, thus resembling a thin film solar cell. The studyhas been carried out in order to deeply understand how the presence of corners(nanobrick) or rounded edges (nanosphere) and the contact surfaces between the metalnanoparticle and the semiconductor affect the scattering when a finite Si layer isconsidered right below the nanoparticles. Arrays of such silver nanoparticles have alsobeen investigated through a proprietary finite-difference time-domain-based code.The comparison with a typical configuration, where the semiconductor layer issemi-infinite, leads us to note that, in dependence on the shape and size of thenanoparticles, the finite layer, which acts as a Fabry–Pérot resonant cavity, is able toexceptionally twist the forward and backward scattering. In particular the forwardscattering in all cases is enhanced, whereas the backward scattering seems to be moresensitive to the interference induced by resonances rising in the finite dielectriclayers, since it exhibits opposite effects depending on the nanoparticle shapes.