Enhanced Ultra-Thin a-Ge:H Solar Cells by Plasmonic Nanoparticles Embedded in the Optical Resonant Cavity

This work compares the impact of periodic arrays of dielectric and plasmonic nanoparticles placed adjacent to, above and below, the a-Ge:H absorber layer in ultra-thin optical cavity solar cells. We take advantage of the bottom-up facet of nanosphere lithography to encapsulate individual Ag nanoparticles in thin SiO2 layers. We show both dielectric and plasmonic nanoparticles placed below the absorber give significant enhancements in quantum efficiency compared to a flat reference. Furthermore, we show major differences in current generation arise between plasmonic and dielectric nanoparticles when they are placed above the absorber.