Evaporation-assisted formation of three-dimensional photonic crystals

The process of evaporation-assisted formation of three-dimensional photonic crystals was studied. The photonic crystals were fabricated by stacking uniform-sized silica spheres into regularly arranged structure with solvent evaporation and sedimentation. Effects of important process parameters, including type of solvent (water and ethanol), system temperature (40 degrees and 60 degrees C), and material for sedimentation cell (quartz, polymethyl methacrylate, and Teflon), on structure regularity of the resulting photonic crystal were investigated. The structure regularity was evaluated with scanning electron microscope graphs and stop band depth achieved in optical absorption spectra. As revealed from the experimental results, photonic crystals of better quality were obtained by using suspending solvents of higher surface tension (water), lower system temperatures (40 degrees C), and sedimentation cell materials of higher critical surface tension of wetting (quartz).