(310b) Periodically Nanostructured Materials Templated From Self-Assembled Colloidal Crystals

Self-assembled colloidal crystals are ideal scaffolds for templating periodic nanostructured materials that are not easily available by microfabrication. Unfortunately, most of the conventional self-assembly techniques are not compatible with standard microfabrication, impeding scale-up to an industrial-scale fabrication. Here we report two simple yet scalable nonlithographic approaches to fabricate large-area, periodically textured surfaces by using self-assembled colloidal crystals as templates. In the first approach, 3D ordered colloidal crystals, made by convective self-assembly or our recently developed spin-coating technique, are used as templates to create 2D surface gratings, provided the subconformal physical vapor deposition of materials only occurs on the periodic surfaces of the templates. The technique allows the production of surface gratings from a large variety of functional materials, such as metals, semiconductors, and dielectrics. In the second approach, two-dimensional non-close-packed colloidal crystals fabricated by the spin-coating process are used as structural templates to make metallic nanohole arrays. These periodic metallic nanoholes can further be used as templates to create wafer-scale metallic nanopyramid arrays with nanoscale tips and high tip density. We show that these templated nanomaterials are promising candidates for developing surface-enhanced Raman scattering (SERS) substrates and subwavelength nanooptics.