Periodic Arrays of Epitaxially Aligned Atomically Flat Single-Crystal Gold Nanoplates

Well-tailored nanomaterials with a single-crystal character provide ideal building blocks for on-chip plasmonic devices. Although colloidal methods have demonstrated mastery over the synthesis of such structures, it has proven quite difficult to deploy these same nanomaterials on substrate surfaces in a highly deterministic manner where precise control over position and orientation is ensured. Only three examples currently exist in the literature where standalone single-crystal noble metal nanoplates have been formed on substrate surfaces in periodic arrays. These demonstrations, while impressive, are deficient in that they have either been demonstrated over small areas (< 1 mm²) or where the nanoplate yield is low (78%). In this talk, we demonstrate the utility of using a crystalline substrate as the primary driver for forming substrate-based gold seeds with the internal defect structures and crystallographic alignment required for nanoplate growth. Using this capability along with other controls that are unique to substrate-based syntheses, we implement chemical reduction methods for generating large-area arrays of gold hexagonal and triangular nanoplates. The devised methods, hence, advance the integration of single-crystal gold nanoplates into device platforms and provide an overall fabrication strategy that is adaptable to other nanomaterials.