Minimizing scattering from antireflective surfaces replicated from low-aspect-ratio black silicon

The scattering properties of randomly structured antireflective black silicon polymer replica have been investigated. Using a two-step casting process, the structures can be replicated in Ormocomp on areas of up to 3 in. in diameter. Fourier analysis of scanning electron microscopy images of the structures shows that the scattering properties of the surfaces are related to the spatial periods of the nanostructures. Structures with a dominating spatial period of 160 nm, a height of 200 nm, and aspect ratio of 1.3 show insignificant scattering of light with wavelength above 500 nm and lower the reflectance by a factor of two.