Plasmonic metal–insulator–metal (MIM) triangular gold nanodisk arrays via colloidal lithography: scalable platforms for high electric field enhancement and light confinement

Abstract Plasmonic nanostructures enable strong electromagnetic field confinement, offering significant potential for sensing, spectroscopy, and nanophotonic applications. In this study, we present the design, simulation, fabrication, and experimental validation of triangular gold nanodisk arrays fabricated using colloidal lithography—a scalable and cost-effective technique. Finite element method simulations reveal that these structures exhibit strong near-field confinement, angle-robust plasmonic resonances (little shift from 0°–80° incidence) and polarization-independent behavior (due to the high symmetry of the array), with maximum electric field enhancement reaching 310 in a 10 nm dielectric gap. Experimental reflectance measurements confirm the simulated absorptance spectra, demonstrating excellent agreement across various gap thicknesses. Results indicate that thinner gap layers favor stronger field enhancement, while thicker gaps offer sharper resonance dips beneficial for sensing applications. This work highlights the potential of colloidal lithography-fabricated triangular nanodisk arrays as practical platforms for plasmon-enhanced devices. To our knowledge, this is the first demonstration of triangular metal–insulator–metal nanodisk arrays fabricated via a scalable colloidal process, achieving performance comparable to e-beam-fabricated structures.