Fabrication of Au nanotips via meniscus-guided 3D printing

Gold nanotips are highly important due to their excellent electron emission properties and strong electromagnetic field enhancement characteristics. The fabrication of gold nanotips has predominantly relied on electrochemical etching, a method offering high yield and low cost, but it suffers from issues such as impurity contamination during processing and the formation of non-uniform tips. In this study, we propose a novel and simple fabrication method for gold nanotips using a meniscus-guided three-dimensional (3D) printing technique. This bottom-up approach uses a liquid meniscus formed between a nanopipette and a substrate to create 3D structures, with precise control over process parameters, enabling the formation of structures with a wide range of diameters, shapes, and configurations. By precisely increasing the pulling speed, it is possible to decrease the diameter of the printed structures. Via two-step 3D printing optimization approach, we successfully fabricated an Au nanotip with a diameter of 100 nm on top of the 3D structure. Our technique offers a robust yet simple new route to fabricate nanotips and opens up a multitude of potential applications in fields such as nano-optics, materials science, and surface analysis.