Improved anti-reflective properties of amorphous silicon films deposited on Al nanoconcave arrays

The anti-reflective properties of amorphous silicon (a-Si) films deposited directly on Al nanoconcave arrays with various interpore distances ( D c ) were studied. The Al anodized at 195 V ( D c =456.7 nm) and covered by a 277-nm a-Si layer demonstrated the best light- trapping efficiency. It absorbed up to ~86% of incident light. Average reflectivity under AM1.5 solar spectrum is strongly correlated to height alteration at the a-Si front surface. Further optimization found that D c and film thickness of 450–500 nm and 250–300 nm, respectively, take full advantage of the excellent optical properties of this simple, low cost material suitable for large scale production.