Enhanced Light–Matter Interactions With a Single Sn Nanoantenna on Epitaxial Graphene

Abstract Surface‐enhanced Raman spectroscopy (SERS) is a powerful tool for amplifying inelastic light scattering in low‐dimensional materials. Graphene, with its chemical stability, tunable electronic properties, and Raman‐active phonons, provides a compelling platform for understanding underlying coupling mechanisms and advancing applications. This study reports on a novel SERS architecture based on single Sn nanoantenna and an intercalated metallic 2D Sn layer, offering a robust, tunable alternative to conventional noble metal substrates. Exploiting the plasmonic and interfacial properties of Sn, this system achieves over two orders of magnitude enhancement in the Raman response of graphene. Comparative analysis of Sn nanoantenna on both charge‐neutral quasi‐free‐standing monolayer graphene (QFMLG) and intrinsically doped epitaxial monolayer graphene (MLG) on SiC(0001) reveals that localized surface plasmon resonance (LSPR)‐mediated coupling drives the enhancement. Concurrent frequency shifts point to dynamic interactions and LSPR‐induced hot carrier doping effects. Remarkably, the inclusion of an intercalated metallic 2D Sn layer at the graphene/SiC interface further boosts the SERS signal, emulating plasmonic nanocavity modes. These findings establish Sn nanostructures and confined 2D Sn layer as versatile, non‐noble SERS platforms with strong potential for integration into next‐generation nanoscale sensing technologies.