High-Performance SPR Sensor Using Wurtzite Nitride Semiconductors and TMDC: a Comparative Study

This theoretical study focuses on the performance of the surface plasmon resonance (SPR) sensor by strategically including various heterostructures in between the plasmonic metal and sensing medium. The heterostructure consists of a wurtzite nitride semiconductor and a two-dimensional (2D) material, specifically transition-metal dichalcogenides (TMDC). The angular interrogation approach is used to assess the sensor’s efficacy which includes all commonly used critical parameters. The study also outlines the range of refractive indices (RI) in the sensing medium that elicit exceptional and notable responses from the proposed SPR structure. Based on the sensitivity, detection accuracy (DA), and figure of merit (FOM) values, it is determined that a TMDC material, specifically tungsten disulfide (WS₂), combined with a wurtzite nitride semiconductor (such as gallium nitride, indium nitride, or aluminum nitride), offers the best performance. Among all heterostructures, GaN-WS₂ exhibits the highest sensitivity. In contrast, AlN-WS₂ exhibits remarkable performance in terms of DA, FOM, and the evanescent field intensity factor. Furthermore, the proposed SPR structure with InN-WS₂ demonstrates maximum shifts in resonance angle, occurring within sensing RI range of 1.372 to 1.389. Similarly, AlN-WS₂ exhibits the maximum shifts in resonance angle within the range from 1.387 to 1.4. GaN-WS₂, however, shows the strongest response to resonance angle shifts within the range from 1.38 to 1.396.