title: Thickness measurement of colloidal opal crystal growth by Bragg reflection.
abstract: This study investigates a simple method for thickness estimation with single layer accuracy for self-assembling opal crystals prepared by the dip-coating method. The thickness (number of layers) of the opal crystals was estimated by an analysis of the optical reflectance from s-polarization incident light, and then verified with SEM. The opal crystals were considered as periodic dielectric layers and were analyzed with the transfer matrix method. The reflectance simulation showed a good agreement with the experimental results. The lattice constant and the thickness were determined at the peak position and by the fringes of the reflection spectra, respectively.
authors.affiliation: Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Ming-Zheng
authors.initials: MZ
authors.lastname: Lin
authors.forename: Guan-Hui
authors.initials: GH
authors.lastname: Li
authors.forename: Ming-Yau
authors.initials: MY
authors.lastname: Chern
authors.forename: Chung-Wen
authors.initials: CW
authors.lastname: Lan