Nanofabrication technology for single-crystalline metal nanoparticle ensembles using nanotemplate-guided thermal dewetting

Metal nanoparticle (NP) research has made significant progress over the past few decades, and now a wide range of materials with well-controlled size and dispersity are available [1]. However, far less progress has been achieved in realizing techniques for controlling the spatial position of NPs in ensembles with predefined arrangements. This is especially important for nanoplasmonics applications, where the optical response of metal NP ensembles is governed by the spatial arrangement of NPs [2,3]. Here, we report a hybrid nanofabrication technology for realizing single-crystalline (SC) metal NP ensembles, such as trimers, heptamers, and periodic arrays. Top-down engineered nanotemplates results in the deterministic formation of isolated polycrystalline (PC) gold islands with precise volume and position, which are transformed into SC NPs using bottom-up self-assembly based on nanotemplate-guided thermal dewetting.