A vertical, high density and sub-100 nm Si nanorod array fabricated by nanosphere template for photovoltaic application

Large-area vertically aligned silicon nanowire arrays have been successfully fabricated on Si substrate by templated catalytic etching process with controlled length and density. The formation of silicon nanowire arrays from anodic electrochemical etching of silicon by silver catalysts. The length of nanowire is defined by the duration of the etching process. This approach was also used to prepare microcrystalline silicon (μc-Si) nanowire arrays. Using optical transmission and reflection measurements on thin μc-Si films, we demonstrate that μc-Si nanowire arrays have low transmission and reflective losses compared to planar, due to strong light-trapping effect. Polystyrene nanospheres are used as a template whereas the formation of polystyrene nanospheres was based on the modified block copolymer nanopatterning with diameter of 30 nm. The density of closely packed PS nanospheres is as high as 10¹¹/cm².