Surface Plasmon Resonance-Based Sensors Using Nano-Ribbons of Graphene and WSe2

We show performance enhancement of surface plasmon resonance (SPR)-based sensors using the nano-ribbons of 2D materials such as graphene and WSe2. 2D material-based structures are useful for refractive index sensing. In this work, conventional graphene-/WSe2-based sensors (in which continuous film of graphene or WSe2 is coated on metal) and graphene/WSe2 nano-ribbon-based sensors are investigated for high quality factors and detection accuracies. Numerical simulations using rigorous coupled wave analysis (RCWA) have been carried out to analyze the sensing performance of the sensors. We show that the possible maximum quality factors 164.28 RIU−1 (162.5 RIU−1) and detection accuracy 0.82 (0.81), can be achieved using conventional sensor based on graphene (WSe2). To improve the performance, we propose a sensor consisting graphene/WSe2 nano-ribbons instead of graphene/WSe2 films. It is shown that by using the nano-ribbons, we could enhance the quality factor by 12.5% (164.28 RIU−1 to 184.97 RIU−1) in case of graphene and 11.4% (162.5 RIU−1 to 181.11 RIU−1) in case of WSe2. Detection accuracy could be improved from 0.82 to 0.92 for graphene nano-ribbons and 0.81 to 0.90 for WSe2 nano-ribbons. Proposed nano-ribbon-based sensors exhibit better sensing performance in comparison to conventional continuous film-based sensors. The study will be useful for designing graphene-/WSe2-based gas sensors and biosensors.