Open AccessPeriodic Si nanopillar arrays by anodic aluminum oxide template and catalytic etching for broadband and omnidirectional light harvesting
Author(s) -
Hsin Ping Wang,
Kun-Tong Tsai,
K. Robert Lai,
Tzu Chiao Wei,
YuhLin Wang,
Jr Hau He
Publication year - 2011
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.20.000a94
Subject(s) - nanopillar , materials science , etching (microfabrication) , optics , optoelectronics , wavelength , refractive index , raman scattering , fresnel equations , omnidirectional antenna , raman spectroscopy , nanotechnology , layer (electronics) , nanostructure , telecommunications , computer science , antenna (radio) , physics
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