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Abstract
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Surface enhanced Raman scattering (SERS) is a highly sensitive and precise technique that enables the acquisition of high-quality spectra from materials in tiny quantities, down to the single-molecule level. Today, this technique, with its high signal enhancement factor, is considered an efficient tool for molecular detection in biosensors. This article will present and investigate the impact of uses of a novel hybrid silver-aluminum structure, a sensor, and also study the enhancement of SERS signal due to the plasmonic coupling effects. The results indicate that the hybrid multi-shape structure enhances the signal and enables a noticeable frequency shift in the Raman spectrum. Furthermore, the role of localized surface plasmon resonance (LSPR) and surface plasmon resonance (SPR) coupling in improving SERS performance is being investigated. It is found that the presence of multi-shape nanoparticles and the proposed arrangements optimize the plasmonic coupling between the localized surface plasmon and the surface plasmons of silver (Ag) and aluminum (Al), leading to an increased concentration of the electromagnetic field in the hotspot regions. We also present the results, the influence of various parameters on the spectral characteristics, and signal enhancement of SERS in the hybrid multi-shape structure. In this regard, the effect of the change in the inner radius of the nanostar from 10 to 100 nm and the use of different sequential arrangements of plasmonic materials, including gold (Au), silver (Ag), copper (Cu), aluminum (Al), and platinum (Pt), on electromagnetic field enhancement and SERS signal are being investigated. We show that in all configurations, the maximum SERS signal intensity occurs at an inner radius of 17.2 nm, reaching a value of 3.884 × 107 /m. Additionally, the results for different sequential plasmonic material arrangements indicate that the Ag _ Al _ Ag configuration achieves the highest SERS signal intensity, with a value of 3.67328 × 108
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