Enhanced performance of SnSe-Graphene hybrid photonic surface plasmon refractive sensor for biosensing applications

In this study, we developed a simple hybrid structure and an appropriate numerical analysis method for a prism-based surface plasmon refractive index biosensor by using an angular interrogation method. The proposed sensor comprised a prism filled with a hybrid of gold (Au), alpha fin selenide (alpha-SnSe), and graphene, and a sensing medium. Monolayers of alpha-SnSe with a similar structure to graphene and phosphorene have exceptional optoelectronic properties and they have attracted much attention as two-dimensional (2D) materials in a similar manner to other 2D material family members. The performance parameters were determined in terms of the sensitivity, detection accuracy (DA), and quality factor (QF). The results demonstrated the improved overall performance of the proposed sensor. Inserting an alpha-SnSe layer between gold and graphene increased the sensitivity of the sensor, and its sensitivity was higher than those of previously reported sensors. All of the performance parameters were enhanced for this hybrid sensor, which is not possible with sensors based only on graphene. Increasing the number of graphene-only layers improved the sensitivity but decreased the DA and QF. The effect of the electric field distribution on the inserted graphene layers was analyzed with the finite difference time domain (FDTD) technique using Lumerical FDTD solution commercial software. The proposed biosensor may facilitate novel sensing applications.