title: Improved broadband and quasi-omnidirectional anti-reflection properties with biomimetic silicon nanostructures.
abstract: Nature routinely produces nanostructured surfaces with useful properties, such as the self-cleaning lotus leaf, the colour of the butterfly wing, the photoreceptor in brittlestar and the anti-reflection observed in the moth eye. Scientists and engineers have been able to mimic some of these natural structures in the laboratory and in real-world applications. Here, we report a simple aperiodic array of silicon nanotips on a 6-inch wafer with a sub-wavelength structure that can suppress the reflection of light at a range of wavelengths from the ultraviolet, through the visible part of the spectrum, to the terahertz region. Reflection is suppressed for a wide range of angles of incidence and for both s- and p-polarized light. The antireflection properties of the silicon result from changes in the refractive index caused by variations in the height of the silicon nanotips, and can be simulated with models that have been used to explain the low reflection from moth eyes. The improved anti-reflection properties of the surfaces could have applications in renewable energy and electro-optical devices for the military.
authors.forename: Yi-Fan
authors.initials: YF
authors.lastname: Huang
authors.forename: Surojit
authors.initials: S
authors.lastname: Chattopadhyay
authors.forename: Yi-Jun
authors.initials: YJ
authors.lastname: Jen
authors.forename: Cheng-Yu
authors.initials: CY
authors.lastname: Peng
authors.forename: Tze-An
authors.initials: TA
authors.lastname: Liu
authors.forename: Yu-Kuei
authors.initials: YK
authors.lastname: Hsu
authors.forename: Ci-Ling
authors.initials: CL
authors.lastname: Pan
authors.forename: Hung-Chun
authors.initials: HC
authors.lastname: Lo
authors.forename: Chih-Hsun
authors.initials: CH
authors.lastname: Hsu
authors.forename: Yuan-Huei
authors.initials: YH
authors.lastname: Chang
authors.forename: Chih-Shan
authors.initials: CS
authors.lastname: Lee
authors.forename: Kuei-Hsien
authors.initials: KH
authors.lastname: Chen
authors.forename: Li-Chyong
authors.initials: LC
authors.lastname: Chen
mesh_terms: D040761:Biomimetic Materials / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D008027:Light; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods*; D055096:Optical Devices; D010316:Particle Size; D010783:Photometry / Q000379:methods*; D012542:Scattering, Radiation; D012825:Silicon / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D046911:Macromolecular Substances; D012825:Silicon