One-step fabrication of metal nanostructures by high-throughput imprinting

TL;DR

This paper introduces a novel high-throughput nanoimprinting technique for crystalline metals, enabling the creation of uniform, monocrystalline nanostructures with extremely high aspect ratios and feature sizes below grain dimensions.

Contribution

It demonstrates superplastic nanoimprinting of crystalline metals below melting temperature, producing nanowires and hierarchical structures with unprecedented precision and crystallinity.

Findings

Able to replicate features as small as 8 nm

Produced monocrystalline nanostructures from polycrystalline metals

Achieved aspect ratios up to ~2000

Abstract

Direct nanoimprinting provides a simple and high-throughput route for producing uniform nanopatterns at great precision and at low costs. However, applying this technique to crystalline metals has been considered as impossible due to intrinsic limitation from grain size effect. Here we demonstrate direct superplastic nanoimprinting (SPNI) of crystalline metals well below their melting temperatures (Tm), generating ordered nanowire arrays with aspect ratio up to ~2000. Our investigations of replicating metal hierarchical nanostructures show the capability of imprinting features as small as 8 nm, far smaller than the grain size of bulk metals. Most surprisingly, the prepared metal hierarchical nanostructures were found possessing perfect monocrystalline structures. These findings indicate that nanoimprinting of crystalline metals below Tm might be from lattice diffusion. SPNI as a one-step and highly controlled high-throughput fabrication method, could facilitate the applications of metal nanostructures in bio-sensing, diagnostic imaging, catalysis, food industry and environmental conservation.