Nanowire arrays with controlled structure profiles for maximizing optical collection efficiency

Hung Chih Chang, Kun Yu Lai, Yu An Dai, Hsin Hua Wang, Chin An Lin, Jr-Hau He*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

84 Scopus citations

Abstract

The nanowire array (NWA) layers with controlled structure profiles fabricated by maskless galvanic wet etching on Si substrates are found to exhibit extremely low specular reflectance (<0.1%) in the wavelengths of 200-850 nm. The significantly suppressed reflection is accompanied with other favorable antireflection (AR) properties, including omnidirectionality and polarization-insensitivity. The NWA layers are also effective in suppressing the undesired diffuse reflection. These excellent AR performances benefit from the rough interfaces between air/NWA layers and NWA layers/substrate and the decreased nanowire densities, providing the gradient of effective refractive indices. The Raman intensities of Si NWAs were enhanced by up to 400 times as compared with the signal of the polished Si, confirming that the NWA layers enhance both insertion and extraction efficiencies of light. This study provides an insight into the interaction between light and nanostructures, and should contribute to the structural optimization of various optoelectronic devices.

Original languageEnglish (US)
Pages (from-to)2863-2869
Number of pages7
JournalEnergy and Environmental Science
Volume4
Issue number8
DOIs
StatePublished - Aug 1 2011

ASJC Scopus subject areas

  • Environmental Chemistry
  • Renewable Energy, Sustainability and the Environment
  • Nuclear Energy and Engineering
  • Pollution

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