Michael James Mcfarland

Two-dimensional nonclose-packed colloidal crystals formed by spincoating

We report a simple spin-coating technique for the production of monolayer nonclose-packed colloidal crystals. Dispersions of submicron silica spheres in triacrylate monomers are spincoated and polymerized to form two-dimensional colloidal crystal-polymer nanocomposites. By removing the polymer matrix, wafer-scale nonclose-packed colloidal crystals with high crystalline quality can be made. The technique is compatible with standard microfabrication and allows for the production of microstructures for potential devices. Normal-incidence reflectivityspectra in the visible and near-infrared regions show sharp peaks due to Bragg diffraction from the colloidalmonolayers. The peak position matches with the theoretical prediction using scalar wave approximation.