Periodic silicon nanocone arrays with controllable dimensions prepared by two-step etching using nanosphere lithography and solution

An electroless chemical etching technique using polystyrene nanospheres as a self-assembled mask is developed to fabricate size-controllable, periodic silicon nanopillars (NPs) and subsequent nanocone (NC) arrays. The Si NCs are obtained based on the NPs structure using cost-effective ammonia-related etching chemistry. The diameter, height, and periodicity of the NCs can be systematically controlled. Optical measurement shows a good improvement in the reduction of reflectance properties with Si NCs structures. This method is potentially beneficial to many device applications including super-capacitors, batteries, solar cells, etc.