Surface profile-controlled close-packed Si nanorod arrays for self-cleaning antireflection coatings.

We demonstrate the fabrication of surface profile-controlled close-packed Si nanorod arrays (NRAs), using a scalable and integrated circuit compatible process combining colloidal lithography and reactive ion etching. Si NRAs exhibit broadband, omnidirectional, and polarization-insensitive antireflection (AR) 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.