Study of lspr-enhanced absorption for solar cell applications: Preliminary results

The Localized Surface Plasmon Resonance (LSPR) phenomenon exhibited in nano-particles, embedded in a dielectric medium has recently been shown to enhance the absorption as well as the photo-generation effect in several lightsensitive structures including solar cells and photo-diodes. The origin of this enhancement has not yet been sufficiently clarified as there appear to be several mechanisms at play, depending on the particular device structure and configuration. We have conducted computer simulation studies on the absorption enhancement in a silicon substrate by nano-shell-related LSPR, based on a Finite Difference, Time-Domain (FDTD) Analysis. Preliminary results of this study show significant enhancement of up to 10X in the near band gap spectral region of Si, using 40-100nm diameter nano-shells. The enhancement was studied as a function of the metallic Shell thickness, the thickness of an externally coating layer of SiO₂, as well as of various nanoshell shapes. The results suggest that the main enhancement mechanism in this case of tubular nanoshells embedded in Si substrate, is that of field-enhanced absorption caused by the strongly LSPR-enhanced electric field extending into the Silicon substrate.