Figure 2From: Fabrication of inverted zinc oxide photonic crystal using sol–gel solution by spin coating methodOptical and FE-SEM images. (a) Optical image of the self-assembled periodic arrangement polystyrene spheres formed on silicon substrate. (b) Top-view and (c) cross-section magnification FE-SEM images of the self-assembled multilayer of polystyrene spheres.Back to article page