We demonstrate the fabrication of surface profile-controlled close-packed Si nanorod arrays ͑NRAs͒, using a scalable and integrated circuit compatible process combining colloidal lithography and reactive ion etching. Si NRAs exhibit broadband, omnidirectional, and polarization-insensitive antireflection ͑AR͒ properties and enhance the hydrophobicity. The effect of surface profiles of periodic NRAs on the AR and hydrophobicity was investigated systematically. The Si NRAs function as both self-cleaning and AR layers, which offer a promising approach to enhance the solar cell energy conversion efficiency.

In the present work, the SWSs combining AR and enhanced hydrophobic effects was reported. A simple method, which combines sub-wavelength-scale monolayer spheres with a reactive ion etching process, to fabricate AR structures of Si nanorod arrays (NRAs) was used. Spectral reflectance measurements of Si substrates with NRA SWSs showed drastic reduction in reflection over a broad range of wavelengths and a wide range of angle of incidence, demonstrating its ability to broadband and omnidirectional antireflection. The reflectivity and the wettability as a function of diameter, height, of Si NWAs were discussed.