Performance parameters as a function of graphene’s chemical potential for SPR biosensor based on 2D materials

The present research analyze the performance parameters of a surface plasmon resonance (SPR) biosensor such as sensitivity, detection accuracy, quality factor, and combined sensitivity factor as a function of graphene chemical potential in a metal/2D material/graphene multilayer system. The attenuated total reflection of SPR was studied as a function of the number of graphene sheets for different 2D materials (ZnO, MoS${}_2$, MoSe${}_2$, WSe${}_2$, WS${}_2$) and calculated using the transfer matrix method. It was found that there is a critical value of the chemical potential for which the performance parameters change their behavior abruptly for all type of 2D materials used in the biosensor configuration; this chemical potential value is called critical chemical potential. Furthermore, the number of graphene sheets have a strong effect on the performance parameters. Finally, an analytical expression for the sensitivity was deduced, which allows to explain their behavior for the different 2D materials used in the SPR biosensor.