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

Abstract

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 δ = 800 nm. Integrating with AM1.5 solar irradiation, this yields a 70% increase in simulated short circuit current density 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. Simulated time averaged power loss density within a-Si in the vicinity of a silver cross EMN, for unpolarized 700 nm light. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.