Plasmonic Au Array SERS Substrate with Optimized Thin Film Oxide Substrate Layer

Abstract

This work studies the effect of a plasmonic array structure coupled with thin film oxide substrate layers on optical surface enhancement using a finite element method. Previous results have shown that as the nanowire spacing increases in the sub-100 nm range, enhancement decreases; however, this work improves upon previous results by extending the range above 100 nm. It also averages optical enhancement across the entire device surface rather than localized regions, which gives a more practical estimate of the sensor response. A significant finding is that in higher ranges, optical enhancement does not always decrease but instead has additional plasmonic modes at greater nanowire and spacing dimensions resonant with the period of the structure and the incident light wavelength, making it possible to optimize enhancement in more accessibly fabricated nanowire array structures. This work also studies surface enhancement to optimize the geometries of plasmonic wires and oxide substrate thickness. Periodic oscillations of surface enhancement are observed at specific oxide thicknesses. These results will help improve future research by providing optimized geometries for SERS molecular sensors.

Dataset for SERS Plasmonic Array: Width, Spacing, and Thin Film Oxide Thickness Optimization

“…The data presented was produced in [19], and the findings regarding possible SERS improvements are discussed. The data was generated using the FEM via COMSOL Multiphysics modeling software.…”

“…The dataset presented in the supplementary file was found using a FEM computational model [19]. The model simulates the incident light upon the surface of the entire structure, and then calculates the plasmonic electric field enhancement upon the light.…”

“…The Figure 3a in [19]. As with the text files, the beginning lines are reserved for Data 2018, 3, 37 6 of 8 descriptions of the data within the file and are also denoted by "%" symbols at the beginning of each line.…”

“…Lastly are the MATLAB image files which end with ". fig Figure 3a in [19]. These files are created from the data used to create the corresponding figure in [19]; however, their coloration has been changed and matches the figures present here.…”

“…For practical purposes, the nanograting must improve optical enhancement not only in the space between nanowires, but across the whole surface. The data discussed in [19] and provided fully in this paper (see supplemental file) offers a more complete evaluation of the enhanced field along a substrate's surface and its efficacy in SERS.…”