Optimization of 1D photonic crystals to minimize the reflectance of silicon solar cells

This paper presents a process to easily fabricate photonic crystals (PCs) on silicon to increase the efficiency of solar cells by reducing the sunlight reflection in the front surface of the cell. The process, based on laser interference lithography (LIL) and reactive ion etching (RIE), allows creating nanostructures over large areas with different shapes and dimensions. The reflectance of the resulting surface depends on the height, pitch, width and shape of the created PC. In this work, these parameters have been optimized by computer simulation and the best PC so far found has been fabricated on silicon. We obtain a normal reflectance under 10% in the spectral region between 500 and 900 nm without any other material employed as antireflecting coating.