Large-Scale Fabrication of 5 nm Plasmonic Hybrid Nanoslit Arrays.

Jiang, Kexin; Luo, Sihai; Li, Dongxian; Yuan, Qi; Chen, Lijuan; Zhang, Yingfang; Chen, Xiaoliang; Yang, Dongxu et al. · Nano Lett · 2025

basic_science · Level V

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Abstract

Surface plasmon resonance harnessed through nanometer-scale metallic gaps generates intense near-fields, unlocking vast potential for applications in nanophotonics and biosensing. However, the scarcity of scalable and reproducible nanofabrication techniques capable of achieving a sub-10 nm gap remains a significant barrier to widespread implementation. Here, we present a high-throughput method combining deep-UV interference lithography, molecular self-assembly, and peeling to fabricate large-scale arrays of an ∼ 5 nm Au-Ag hybrid nanoslit. These arrays serve as highly effective substrates for surface-enhanced Raman spectroscopy (SERS), demonstrating the ability to detect rhodamine 6G at concentrations as low as 1 pM with an analytical enhancement factor of 2.2 × 10<sup>7</sup>. Specifically, the hybrid nanoslit arrays exhibit significantly higher (by 2.6-fold) field enhancements than monolithic nanoslit arrays due to the in-phase hybridization mode in Au-Ag nanoslit. Our cost-effective, large-scale approach overcomes traditional scalability and hybrid patterning barriers, offering transformative potential for sensitive, reliable SERS-based detection platforms.