Promote Localized Surface Plasmonic Sensor Performance via Spin-Coating Graphene Flakes over Au Nano-Disk Array

Abstract

Although localized surface plasmonic resonance (LSPR) sensors have advantages over regular surface plasmonic resonance (SPR) sensors, such as in sensor setup, excitation method, and cost, they suffer from low performance when compared to SPR sensors, which thus limits their commercialization. Among different methods applied to promote LSPR sensor performance, metal-two-dimensional (2D) hybrid nanostructure has been shown to be an efficient improvement. However, metal-2D hybrid nanostructures may come in a complex or a simple scheme and the latter is preferred to avoid challenges in fabrication work and to be applicable in mass production. In this work, a new and simple gold-graphene hybrid scheme is proposed and its plasmonic sensing performance is numerically evaluated using the finite different time domain (FDTD) method. The proposed sensor can be fabricated by growing a Au nano-disk (ND) array on a quartz substrate and then spin-coating graphene flakes of different sizes and shapes randomly on top of and between the Au NDs. Very high sensitivity value is achieved with 2262 nm/RIU at a 0.01 refractive index change. The obtained sensitivity value is very competitive in the field of LSPR sensors using metal-2D hybrid nanostructure. This proposed sensor can be utilized in different biosensing applications such as immunosensors, sensing DNA hybridization, and early disease detection, as discussed at the end of this article.