| dc.description.abstract | Localized surface plasmon resonance (LSPR) sensors have a wide range of applications, from medical diagnostics to environmental monitoring. In addition, the simplicity of the excitation method leads to simplicity in the sensor setup, which is helpful for device minimization, and may also help in system cost reduction. Generally, LSPR sensors suffer from low performance, which limits their commercialization. In earlier decades, researchers attempted various methods to overcome this problem; however, recently, the integration of plasmonic material, “gold”, with a 2D material, “graphene”, has been found to be a promising way to enhance light-matter interaction, and hence promote LSPR sensor performance.
In this work, four different novel gold (Au)-graphene (G) hybrid nanostructure schemes are proposed and their sensing performance, as a plasmonic sensor, is studied and evaluated numerically using the Finite Difference Time Domain (FDTD) method. The first gold-graphene hybrid nanostructure studied in this project is a periodic array of Au-G spherical core-shell hybrid nanoparticles (NP) placed on top of a quartz substrate. The second is formed by embedding the medium between Au NPs in an array with multilayers of graphene sheets. Third, is direct deposition of a graphene film on top of a Au NP array and finally, spin-coating graphene flakes on top and between a Au NP array. Based on numerical work, the maximum value of sensitivity and the figure of merit of the LSPR sensor achieved here are 4380 nm/RIU and 857.9, respectively, which is very high and competitive with other studies, and presents the Au-G hybrid LSPR sensor as a promising sensor in a variety of applications such as bio-sensing, thereby enhancing its commercialization. At the end of this work, near-field characterization using a near-field scanning optical microscope (NSOM) is applied to the fabricated Au NP array to study light-Au NP interaction and to illustrate how the structure can be utilized as an LSPR sensor. | en |
