Nanostructure for Hybrid Plasmonic Photonic Crystal Formed on Gel-Immobilized Colloidal Crystal Observed by AFM after Drying

Aiming at fabrication of hybrid plasmonic-photonic crystals, gel-immobilized colloidal crystals made of a polystyrene colloidal suspension and an N-(hydroxymethyl)acrylamide-based gel were immersed into an aqueous dispersion of gold nanoparticles. Atomic force microscope (AFM) observations have been performed for the gel-immobilized colloidal crystals with gold nanoparticles deposited on their surfaces. In the present study, the diameter of a colloidal sphere was ca. 190 nm. The diameter of a gold nanoparticle was the same as in a preliminary study, ca. 40 nm. Various immersion times up to two hours were tested. Surface of a sample of 2 h immersion has been observed. Prior to the AFM observation, the sample was dried in a desiccator for 18 h. We have identified a face-centered cubic {111} structure of a colloidal crystal of nearly close packing. Nanoparticles isolated with one another have been observed on the surface of gel-immobilized crystal, which can be regarded as gold nanoparticles from their sizes.