Analyzing the effect of graphene's chemical potential on the performance of a plasmonic sensor in infrared

SPR sensor based on 'glass substrate-Ag film-insulating layer-graphene' plasmonic structure is proposed in the NIR region. The influence of graphene chemical potential (μ) on the sensor's performance, measured in terms of figure-of-merit (FOM), has been analyzed in detail. The analysis suggests that the variation of chemical potential does not affect much the detection sensitivity and detection limit but it affects the FWHM of SPR curve. The variation of FOM with μ follows a certain pattern. In summary, the maximum and almost constant sensing performance may be achieved for 0.9 < μ < 1 eV for graphene monolayer. Also, CaF2 substrate provides much better FOM compared with 2S2G and Si substrates at any value of μ.