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Title: Broadband optical absorption by tunable Mie resonances in silicon nanocone arrays

Nanostructure arrays such as nanowire, nanopillar, and nanocone arrays have been proposed to be promising antireflection structures for photovoltaic applications due to their great light trapping ability. In this paper, the optical properties of Si nanopillar and nanocone arrays in visible and infrared region were studied by both theoretical calculations and experiments. The results show that the Mie resonance can be continuously tuned across a wide range of wavelength by varying the diameter of the nanopillars. However, Si nanopillar array with uniform diameter exhibits only discrete resonance mode, thus can't achieve a high broadband absorption. On the other hand, the Mie resonance wavelength in a Si nanocone array can vary continuously as the diameters of the cross sections increase from the apex to the base. Therefore Si nanocone arrays can strongly interact with the incident light in the broadband spectrum and the absorbance by Si nanocone arrays is higher than 95% over the wavelength from 300 to 2000 nm. In addition to the Mie resonance, the broadband optical absorption of Si nanocone arrays is also affected by Wood-Rayleigh anomaly effect and metal impurities introduced in the fabrication process.
Authors:
 [1] ;  [1] ;  [2] ;  [1] ;  [3] ;  [1] ;  [1] ;  [4] ;  [4] ;  [4]
  1. Fudan Univ., Shanghai (China)
  2. Fudan Univ., Shanghai (China); Key Lab. for Information Science of Electromagnetic Waves (MoE), Shanghai (China); Ames Lab., Ames, IA (United States)
  3. Chinese Academy of Sciences, Shanghai (China)
  4. Ames Lab., Ames, IA (United States)
Publication Date:
OSTI Identifier:
1193750
Grant/Contract Number:
AC02-07CH11358
Type:
Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 5; Journal Issue: 3; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Research Org:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY