Bioinspired broadband antireflection coatings on silicon wafers enabled by a polyimide-assisted self-masking technique.

Here we report a simple self-masking technique for fabricating bioinspired broadband antireflection coatings on both single-crystalline and multicrystalline silicon wafers with the assistance of a polyimide tape. Subwavelength-structured moth-eye nanopillars, which exhibit superior antireflection performance over a broad range of visible and near-IR wavelengths, can be patterned uniformly on the wafer surface by applying a chlorine-based reactive ion etching (RIE) process. The resulting random nanopillars show improved antireflection properties compared with ordered nanopillars templated by colloidal lithography under the same RIE conditions. X-ray photoelectron spectroscopy analysis suggests that energetic bombardment by reactive ions and radicals during RIE sputters the polyimide tape and spontaneously forms nanomasks over the wafer.