Nanopatterning of crystalline silicon with anodized aluminum oxide templates

A novel thin film anodized aluminum oxide templating process was developed and applied to make nanopores with anisotropic etching on crystalline silicon through reactive ion etching, with the purpose of enhancing the anti-reflection of silicon substrates. A unique two-step anodizing method was introduced to create high quality nano-channels and it was demonstrated that this process is superior over a one-step anodization approach. It was found that pore to pore distance and pore density can be tuned by changing the applied potential within a range of 10–80 V. Optical characterization of the nanopatterned silicon showed an average 10% reduction in reflection in the UV–Vis wavelength range.