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Title: Tailoring broadband light trapping of GaAs and Si substrates by self-organised nanopatterning

We report on the formation of high aspect ratio anisotropic nanopatterns on crystalline GaAs (100) and Si (100) substrates exploiting defocused Ion Beam Sputtering assisted by a sacrificial self-organised Au stencil mask. The tailored optical properties of the substrates are characterised in terms of total reflectivity and haze by means of integrating sphere measurements as a function of the morphological modification at increasing ion fluence. Refractive index grading from sub-wavelength surface features induces polarisation dependent anti-reflection behaviour in the visible-near infrared (VIS-NIR) range, while light scattering at off-specular angles from larger structures leads to very high values of the haze functions in reflection. The results, obtained for an important class of technologically relevant materials, are appealing in view of photovoltaic and photonic applications aiming at photon harvesting in ultrathin crystalline solar cells.
Authors:
; ; ;  [1]
  1. Dipartimento di Fisica, Università di Genova, via Dodecaneso 33, I-16146 Genova (Italy)
Publication Date:
OSTI Identifier:
22275524
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 19; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 77 NANOSCIENCE AND NANOTECHNOLOGY; CRYSTAL STRUCTURE; GALLIUM ARSENIDES; GOLD; ION BEAMS; LIGHT SCATTERING; NANOSTRUCTURES; PHOTOVOLTAIC EFFECT; POLARIZATION; REFLECTION; REFLECTIVITY; REFRACTIVE INDEX; SILICON; SOLAR CELLS; SUBSTRATES; TRAPPING; VISIBLE RADIATION