title: Periodic Si nanopillar arrays by anodic aluminum oxide template and catalytic etching for broadband and omnidirectional light harvesting.
abstract: Large-area, periodic Si nanopillar arrays (NPAs) with the periodicity of 100 nm and the diameter of 60 nm were fabricated by metal-assisted chemical etching with anodic aluminum oxide as a patterning mask. The 100-nm-periodicity NPAs serve an antireflection function especially at the wavelengths of 200~400 nm, where the reflectance is decreased to be almost tenth of the value of the polished Si (from 62.9% to 7.9%). These NPAs show very low reflectance for broadband wavelengths and omnidirectional light incidence, attributed to the small periodicity and the stepped refractive index of NPA layers. The experimental results are confirmed by theoretical calculations. Raman scattering intensity was also found to be significantly increased with Si NPAs. The introduction of this industrial-scale self-assembly methodology for light
authors.affiliation: Institute of Photonics and Optoelectronics, Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Hsin-Ping
authors.initials: HP
authors.lastname: Wang
authors.forename: Kun-Tong
authors.initials: KT
authors.lastname: Tsai
authors.forename: Kun-Yu
authors.initials: KY
authors.lastname: Lai
authors.forename: Tzu-Chiao
authors.initials: TC
authors.lastname: Wei
authors.forename: Yuh-Lin
authors.initials: YL
authors.lastname: Wang
authors.forename: Jr-Hau
authors.initials: JH
authors.lastname: He
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry*; D002384:Catalysis; D004566:Electrodes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007909:Lenses; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology / Q000295:instrumentation*; D012825:Silicon / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D000537:Aluminum Oxide; D012825:Silicon