MoS2-Enhanced Toothed Plasmonic Waveguide Sensor for High-Sensitivity Biosensing

We design a toothed plasmonic waveguide sensor with a monolayer MoS₂ located at the metal–dielectric interface and compare its sensing performance with graphene under the same conditions. We optimize the rectangular-tooth dimensions to enhance the interaction between the confined plasmonic field and the surrounding sensing medium. The optimized structure achieves a maximum refractive-index sensitivity of 896 nm/RIU for a tooth size of 80 nm × 50 nm over an RI range of 1.33–1.40. We further evaluate the sensing performance using the refractive indices of healthy tissue, basal cell, and melanoma samples. The transmission spectra exhibit distinct resonance shifts for the different biological samples, demonstrating the ability of the proposed sensor to distinguish small variations in refractive index. A maximum sensitivity of 880 nm/RIU is obtained for the basal cell sample. The comparative analysis shows that MoS₂ provides higher sensitivity than graphene in the proposed configuration and enhances the optical response of the plasmonic waveguide. These results indicate that the proposed sensor offers a compact and highly sensitive platform for refractive-index-based biomedical detection.