The effect of the refractive index profile on the optical response of plasmonic nanostructures inside semiconductors

The inclusion of plasmonic nanostructures inside semiconductors has been explored over the last decades with the prominent application of increasing the efficiency in solar cells. The plasmonic properties were often only phenomenologically explained by comparison of experiments with simulations. In this work we investigated the plasmonic properties of a silver particle inside virtual semiconductors with varying band gaps. Because the particle plasmon peaks strictly followed the virtual semiconductor band gap, it was found that only the maxima in the real part of the refractive index were responsible for the presence of particle plasmon peaks. This model, in which the plasmonic response is to a large extent determined by the semiconductor refractive index profile, explains previous investigations of plasmonic nanostructures inside semiconductors in a simple way and will enable a detailed design and explanation of future nanostructured plasmonic systems for solar cells and other devices.