Effect of sintering on the optical properties of SiO2 colloidal crystal multilayers

High-quality SiO2 colloidal crystal multilayers were fabricated from ethanol solutions by the vertical deposition method and the effect of sintering on the optical properties of the samples was investigated. Optical properties,which are determined by the photonic band structure, weres tudied by means of light transmission and reflection measurements. The morphology of the samples was characterized by scanning electron microscopy (SEM). SEM images illustrate the ordered close package of the spherical colloids in planes parallel to the substrate surface. In addition, the sampie is crackless as a result of an appropriate drying rate. It is shown that with the increase of the sintering final temperature, though the depth and the width of the peak of Bragg diffraction of the sample vary vastly, the peak produces few blue shifts. Optical measurement results were compared favorably to the microstructural properties of the colloidal crystal multilayers.