Stochastic Antireflection Structures on Silicon Fabricated by Reactive Ion Etching

Stochastic Si nanostructures for antireflection (AR) fabricated by reactive ion etching (RIE) are presented for use in different spectral ranges. The lithography-free fabrication enables its application on highly curved surfaces. ALD-coatings of Al2O3 of varying thickness can improve the mechanical stability of such structures while keeping their optical functionality. While typical black silicon structures are suitable for application from VIS to NIR, an RIE-based fabrication process for stochastic AR structures in the longer IR and THz range is presented as well.