Index matching at the nanoscale: light scattering by core–shell Si/SiOx nanowires
in: Nanotechnology (2016)
Silicon nanowires (SiNWs) show strong resonant wavelength enhancement in terms of absorption as well as scattering of light. However, in most optoelectronic device concepts the SiNWs should be isolated by a contact layer. On a geometrical scale this contact layer can act as an index matching layer which could nearly halve the strong reflectance of light by silicon. Our results show that this reduction can be overcome at the nanometer scale, i.e. SiNWs embedded in a silica (SiOx) layer can not only maintain their high scattering cross sections but also their strong polarization dependent scattering. Moreover, we show that it is possible to optically determine the diameters of the embedded nanoscaled silicon (Si) cores. Such effects can be useful for light harvesting or optoelectronic applications.