Fabricación y caracterización óptica de cristales coloidales de alta calidad formados por esferas de SiO₂ de 225 nm de diámetro con empaquetamiento fcc crecidos por el método convectivo de auto-ensamblado de deposición vertical

Objective: Fabrication and optical characterization of close-packed 225 nm SiO₂ -based colloidal crystals. Materials and methods: The vertical convective self-assembly method is used to grow high-quality 225 nm close-packed SiO₂-based colloidal crystals. An annealing process (550°C) is made in order to improve the mechanical stability of the sample. Optical characterization is done by angle-resolved transmission spectroscopy (A-RTS) and structural characterization by Scanning Electron Microscopy (SEM). Results: Both, A-RTS and SEM, show that with the vertical convective self-assembly method, with the appropriate parameters of temperature of evaporation (60°C), volume fraction of the colloidal suspension (0.2% w/w) and acidity (pH=6), highly ordered close packed face centered cubic (fcc) SiO₂ based colloidal crystals are obtained. Conclusions: The growth of high-quality (long range order and defect-free) face centered cubic opalbased photonic crystals is reported.