Sensitivity Enhancement Of Transition Metal 2-Dimensional Nanomaterials-based SPR Biosensors

Biosensor technology plays an important role in life science research,clinical medical testing,environmental safety assessment,food hygiene testing and so on.In recent years,with the progress of technology and the development of detection methods,the detection range and sensitivity of biosensors have also been greatly improved.Surface Plasmonic Resonance(SPR)biosensor has the advantages of high sensitivity,wide detection range,easy to carry and so on.The development speed of SPR biosensor is changing with each passing day.Moreover,products based on SPR sensor technology also play an increasingly important role in biomedical detection,food safety detection and residue detection of consumer goods.In recent years,the introduction of new two-dimensional nanomaterials has brought new strategy for improving the performance of SPR biosensors.Graphene and other two-dimensional nanomaterials have greatly improved the sensitivity of SPR biosensors.However,transition metal sulfur/selenide,which also has excellent two-dimensional nanomaterials,has not been fully studied at present.In this paper,the SPR biosensor based on two-dimensional nano-material molybdenum disulfide(MoS2)was studied.The parameters affecting the sensitivity of SPR biosensor were discussed and optimized.The Kretschmann model was used to simulate the SPR biosensor.The parameters of Au,Si,MoS2 and their thickness were adjusted by software as incident light at a fixed wavelength.The sensitivity of SPR biosensor with different material parameters was discussed.We hoped that this numerical simulation work will guide the sensor fabrication and optimize the parameters.The simulation results showed that the number of MoS2 layers needed to achieve the minimum reflectance decreased according to the Au thickness and Si thickness increasing at 632.8 nm incident wavelength.When the Au thickness and Si thickness were fixed,the minimum reflectance curve decreased first and then increased with the MoS2 layers increasing,which indicated that MoS2 had a significant enhancement effect on SPR phenomenon in a certain range.Under the simulation conditions,the thickness of Au layer were 35 nm,40 nm,45 nm,50 nm;the thickness of Si layer were 0 nm,5 nm,7 nm;the number of MoS2 layers was 0 to 15 layers.SPR curves were drawn to obtain the SPR angle and minimum reflectance,and the corresponding SPR angular variation was obtained by changing the refractive index of the sample.The angular sensitivity was defined and calculated as the ratio of SPR angular variation and refractive index variation.When the thickness of Au layer was 35 nm,the thickness of Si layer was 7 nm and MoS2 layer was 1,the sensitivity of the SPR biosensor was the highest.