(510f) Wafer-Scale Self-Assembly of Coloidal Crystals with Tunable Lattice Spacing

Photonic crystals and plasmonics are two key techniques that could ultimately enable all-optical integrated circuits and quantum information processing. Unfortunately, the development and implementation of these techniques have been greatly impeded by expensive and painstaking top-down nanomanufacturing approaches (e.g., electron-beam lithography). By contrast, bottom-up colloidal self-assembly and subsequent templating nanofabrication provide a much simpler, faster, and inexpensive alternative to nanolithography in creating 3-D highly ordered photonic crystals and plasmonic nanostructures. However, traditional colloidal self-assembly and templating nanofabrication technologies suffer from low throughput, incompatibility with standard microfabrication, and limited crystal structures, which greatly hamper the mass-production and on-chip integration of practical optoelectronic devices. Here we present a scalable bottom-up nanomanufacturing platform for large-scale production of high-quality photonic crystals and a large variety of periodic metal nanostructures with tunable plasmonic properties for next-generation integrated nanooptics. Shear force generated by a microfabrication-compatible spin-coating technique is utilized to align concentrated colloidal suspensions to rapidly form large-area photonic crystals with remarkably large domain sizes and unusual non-close-packed structures. Importantly, by simply controlling the particle volume fraction of the colloidal suspension, the lattice spacing of the shear-aligned crystals can be easily adjusted. This platform technology combines the simplicity and cost benefits of bottom-up colloidal self-assembly with the scalability and compatibility of standard top-down microfabrication. Additionally, they enable scalable templating nanofabrication of a myriad of nanostructured functional materials ranging from plasmonic nanostructures to bioinspired broadband antireflection coatings.