Embedded metal nanopatterns for near-field scattering-enhanced optical absorption

Simulations of metal nanopatterns embedded in a thin photovoltaic (PV) absorber show significantly enhanced absorbance within the semiconductor, with a more than 300\% increase for $\lambda$ = 800 nm. Integrating with AM1.5 solar irradiation, this yields a 70\% increase in simulated short circuit current density and thus power conversion efficiency (single junction $\eta$ = 13\%) in a 60 nm amorphous silicon film. Embedding such metal patterns inside an absorber maximally utilizes enhanced electric fields that result from intense, spatially organized, near-field scattering in the vicinity of the pattern. Appropriately configured (i.e., with a thin insulating coating), this optical metamedium architecture may be useful for increasing PV efficiency in thin film solar cells, including offering prospects for realistic ultrathin hot electron cells.