Nanowires ProximityFeatured with Angular Forgivenessand Far-Reaching Hotspots toward Surface-Enhanced Raman Spectroscopy

Abstract Surface-enhanced Raman spectroscopy (SERS) poses potential for an effective chemical sensing mechanism by providing local volumes, called hotspots, that can induce strong localized surface plasmon resonance. Researchers have endeavored to create hotspots in various forms, among which lies an architecture of randomly entangled plasmonic nanowires (Altun, A. O.; et al. Adv. Mater. 2013, 25 (32), 4431–4436). The superior SERS performance of this design calls for elucidation of the underlying mechanism, for example, from the perspective of electric-field enhancement. Here, we present numerical simulations to characterize the electric-field enhancement around a nanowire dimer at all possible angular orientations and understand the angular forgiveness effect of the crossing-nanowire architecture on the strong, far-reaching field enhancement. Our understanding of the angular forgiveness mechanism can provide insight into the design of an effective SERS substrate using plasmonic nanowires.