High-uniformity, low-cost, ultra-dense arrays of Au-capped plastic nanopillars fabricated via nanoimprint lithography as reliable SERS substrates.

Nanoimprint lithography (NIL) is gradually becoming a powerful tool for the fabrication of periodic nanostructures. This method can offer a more cost-effective solution for large-scale manufacturing compared to methods that only rely on deep ultraviolet (DUV) immersion, since the product of DUV immersion can be utilized as a Si mold to fabricate a reusable plastic stamp mold. In this work, arrays of plastic nanopillars coated with nanostructured gold film exhibiting ultra density prepared through NIL and Au sputtering are successfully developed. The obtained plastic nanopillar substrate is templated from Si nanopillar substrate with a pitch of 90 nm. As a result, the plastic nanopillar features a similar pitch size. Besides, benzenedithiol (BDT) was used as the standard analyte to evaluate the uniformity of the substrates as well as the SERS enhancement effect. Eventually, it is demonstrated that the substrate constituted of Au-capped plastic nanopillar shows a low coefficient of variation (CV) at 5.46 % along with a strong SERS enhancement effect. These performances match with the Si based SERS substrate manufactured via DUV immersion reported in our previous work.