Highly Sensitive GaN-WS2-Based Surface Plasmon Resonance Sensor: a Theoretical Approach

Utilizing an angular interrogation technique, the numerical design of a high-sensitivity surface plasmon resonance (SPR) structure is presented using a heterostructure GaN-WS2, at an operational wavelength of He-Ne laser. The key performance parameters of the proposed sensor are computed and compared with other semiconductor and transition metal dichalcogenide (TMDC)-based SPR sensors. The investigation suggests that GaN has a significant impact on sensitivity. Furthermore, the inclusion of WS2 layer on GaN resulted in a rise in sensitivity to levels comparable to graphene and other TMDC layers on it. Again, the evanescent electric field at the interface is significantly high for the proposed SPR structure. In addition, the values of detection accuracy (DA) and figure of merit (FOM) are superior in comparison to other GaN-TMDS-based SPR structures. The sensor construction with a heterostructure of 5 nm GaN and monolayer WS2 coated on 55-nm silver results in a high sensitivity of 186.59(degrees/RIU), which is incredibly good in comparison to conventional SPR sensors and also, beneficial for the plasmonic research community.