Analysis of engineered aluminum-based plasmonic devices decorated with graphene/2D nanomaterials for enhanced biosensing applications in the near-infrared region

Abstract

The dynamics of light-matter interaction between metal-analyte interfaces can be studied by the surface plasmon resonance phenomenon. Among the plasmonic metals, Aluminum (Al) has become quite a popular choice because of its ability to access a wider spectral range as well as better compatibility with optoelectronic devices. However, the study of Al as a plasmonic material has been almost completely confined to its periodic nanostructures/nanoclusters [1] , and there are limited reports of Al being used as a plasmonic metal in the standard Kretschmann configuration in the near-infrared region. Therefore, the proposed work reports the modified Kretschmann configuration with Al as a plasmonic metal for Surface Plasmon (SP) excitation to capture the minute changes in the refractive index of the analyte. The present work has also employed the advantages of Graphene (Gr) in context to increased interactions with biomolecules since Gr has emerged as an attractive alternative to be used as a biomolecular recognition element to functionalize the metal layer. Along with it, silicon is used as a high-index dielectric which enhances the sensitivity to produce accurate detection results. An optimized number of stacks of Silicon-Gr sheets are utilized for bio-sensing applications after negotiating the trade-off between important parameters like sensitivity and Figure of Merit (FOM) as shown in Fig. 1(a) . To demonstrate a bio-sensing application in the communication band, varying concentrations of the Leptospira bacterium in the form of different refractive indices are analyzed among the infected rodents and the sensitivity (S) and FOM were found to be 200°/RIU and 95.23 RIU -1 respectively at the wavelength of 1550 nm which are much better than the previously reported results in the literature.