Fabrication of high-contrast gratings for a parallel spectrum splitting dispersive element in a concentrated photovoltaic system

High-contrast gratings are designed and fabricated and their application in a parallel spectrum splitting dispersive element is proposed that is found to have the potential to improve the solar conversion efficiency of a concentrated photovoltaic system. This proposed system will also lower solar cell cost in the concentrated photovoltaic systems by replacing the expensive tandem solar cells with cost-effective single-junction solar cells. The structures and parameters of the high-contrast gratings for the dispersive element are numerically optimized, and a large-area fabrication is experimentally demonstrated using nanoimprint lithography and dry etching. Both the quality of the material and the performance of the fabricated device are experimentally characterized and discussed. (C) 2014 American Vacuum Society.