Photonic crystal and structural properties of synthesized opal films filled with the iron oxides: hematite
magnetite (Fe3O4) were investigated by means of scanning electron microscopy, X-ray diffraction, and Fourier
transforme spectroscopy. Hematite was infiltrated into opal film pores without depositing the oxide onto the outer film
surface by the method of lateral infiltration under capillary forces from a liquid precursor. The synthesis of Fe3O4 was
performed in the opal pores using α→Fe2O3 as a precursor. The evolution of Bragg diffraction line from the (111) planes
of the f.c.c lattice of the opal-α-Fe2O3 film with a various filling degree was studied. The maximum filling degrees both
of opal- α-Fe2O3 and of opal-Fe3O4 films, estimated from the reflection spectra, appeared to be similar and equal to
~ 55% of the pore volume. The reversible chemical transformation of fillers in opal pores α-Fe2O3→Fe3O4→α-Fe2O3
changes only the filler dielectric constant but does not practically produce structural defects that could affect the
photonic crystal properties of the composite.
The opal-GaN-ZnS:Mn composites with various GaN:ZnS ratios were synthesized by chemical bath deposition. These materials are perfect three-dimensional photonic crystals, which produce effective photo- and electroluminescence at room temperature. The emission spectra are considerably modified by the photonic crystal structure to become anisotropic in accordance with the photonic band gap angular dispersion.