Synthesis of amorphous silicon/magnesia based direct opals with tunable optical properties

► The effective refractive index of artificial opals has been modulated through magnesiothermic and wet etching processes. ► The magnesiothermic reduction of silica spheres assembled in a fcc lattice produces amorphous silicon/magnesia opals. ► Amorphous silicon/magnesia opals can be easily converte...

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Bibliographic Details
Published in:Optical materials 2011-01, Vol.33 (3), p.563-569
Main Authors: Pallavidino, Luca, Liscidini, Marco, Virga, Alessandro, Chiodoni, Angelica, Descrovi, Emiliano, Cos, Joaquin, Andreani, Lucio Claudio, Pirri, Candido Fabrizio, Geobaldo, Francesco, Giorgis, Fabrizio
Format: Article
Language:English
Subjects:
Amorphous silicon
Etching
Magnesium oxide
Opals
Optical properties
Optical spectroscopies
Photonic crystals
Porous silicon
Reduction
Reflectance
Silicon dioxide
Spectra
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Summary:► The effective refractive index of artificial opals has been modulated through magnesiothermic and wet etching processes. ► The magnesiothermic reduction of silica spheres assembled in a fcc lattice produces amorphous silicon/magnesia opals. ► Amorphous silicon/magnesia opals can be easily converted in oxidized porous silicon, preserving the ordered structure. ► a-Si/MgO opals which could be exploited for the fabrication of other photonic crystals with different symmetry. ► The etched structures could be suitable for emitting dye impregnations, taking advantage of the porous structure. The effective refractive index of silica based artificial opals can be strongly modulated through magnesiothermic and wet etching processes. The magnesiothermic reduction of silica spheres assembled in a fcc lattice produces amorphous silicon/magnesia matrix, which can be easily converted in oxidized porous silicon, preserving the ordered structure. These results are verified by electron microscopies and IR/Raman spectroscopies. The optical properties are analyzed in terms of the experimental reflectance spectra. By comparing the measured data to rigorous calculations, the good quality of the opaline replicas is demonstrated.
ISSN:0925-3467
1873-1252
DOI:10.1016/j.optmat.2010.11.003