Sensitivity Enhancement of Transition Metal Dichalcogenides/Silicon Nanostructure-based Surface Plasmon Resonance Biosensor

Abstract

In this work, we designed a sensitivity-enhanced surface plasmon resonance biosensor structure based on silicon nanosheet and two-dimensional transition metal dichalcogenides. This configuration contains six components: SF10 triangular prism, gold thin film, silicon nanosheet, two-dimensional MoS2/MoSe2/WS2/WSe2 (defined as MX2) layers, biomolecular analyte layer and sensing medium. The minimum reflectivity, sensitivity as well as the Full Width at Half Maximum of SPR curve are systematically examined by using Fresnel equations and the transfer matrix method in the visible and near infrared wavelength range (600 nm to 1024 nm). The variation of the minimum reflectivity and the change in resonance angle as the function of the number of MX2 layers are presented respectively. The results show that silicon nanosheet and MX2 layers can be served as effective light absorption medium. Under resonance conditions, the electrons in these additional dielectric layers can be transferred to the surface of gold thin film. All silicon-MX2 enhanced sensing models show much better performance than that of the conventional sensing scheme where pure Au thin film is used, the highest sensitivity can be achieved by employing 600 nm excitation light wavelength with 35 nm gold thin film and 7 nm thickness silicon nanosheet coated with monolayer WS2.

Theoretical design of a surface plasmon resonance sensor with high sensitivity and high resolution based on graphene–WS2 hybrid nanostructures and Au–Ag bimetallic film

“…The rst layer is the SF11 prism and its refractive index is n 1 ¼ 1.52. 25 The second layer is Ag lm and the third layer is Au lm. The complex refractive index of thin-metal is obtained from the eqn (1) at 633 nm.…”

Investigation of the performance of thermally generated gold nanoislands for LSPR and SERS applications

“…In SPR the maximum excitation of surface plasmons is detected by monitoring the reflected power from a prism coupler as a function of incident angle or wavelength [3]. This technique can be used to observe nanometer scale changes in thickness, to detect the alteration of the refractive index, to investigate different surface reactions or absorption of biomolecules on the surface of a metallic layer [4]. The advantages of sensors based on SPR are the high sensitivity and possibility of parallel measurements.…”

High-sensitivity integrated devices based on surface plasmon resonance for sensing applications

“…[6] (graphene/graphene-oxide-based SPR), Ref. [8] (silicon nanostructures), Ref. [18] (maximum theoretical limit for Kretschmann configuration), Ref.…”

“…These conditions are fulfilled using a variety of geometrical and material configurations [6]. Among them, we can mention the use of buffer layers [7][8][9], nanoparticles [10][11][12][13], or by coupling to a grating located at the interface [14][15][16][17].…”