Versatile fabrication of self-assembled metallic nanoparticle arrays

One of the challenging aspects of nanotechnology is the development of an effective and potentially universal method to place nanoparticles (NPs) into spatially well-defined, ordered, defect-free arrays. This can be achieved using "top-down" approaches, such as optical, electron beam, focused ion-beam and scanning probe lithography, or "bottom-up" approaches based on self-assembly. Here, we report the simple and rapid electrochemical generation of periodic surface defects, used to fabricate metallic NP arrays having good feature size and spacing control over a large area, without involving costly and time-consuming nanolithographic methods. Our high-throughput nanofabrication approach combines electrochemical anodization to quickly and reproducibly form a highly ordered Ta-based nanotemplate, in the form of inverted hemispherical caps (dimples), with the simplicity of thin metallic film dewetting techniques, forming a self-assembled metallic (individual metals or alloy) NP array. These can be used as nanoelectrode arrays that may have useful applications in analytical chemistry, biosensing, and electrocatalysis.