design and simulation of graphene/2d interlayer surface plasmon resonance biosensor based on ellipsometry method

Two-dimensional nanomaterials have attracted increasing attention for enhancing surface plasmon resonance (spr) biosensors application. in this work, we use the graphene layer to improve the sensitivity of the spr biosensors based on the conventional kretschmann configuration. we employ tungsten disulfide (ws2) and molybdenum disulfide (mos2) two-dimensional materials as an interlayer to enhance the sensitivity of au/graphene biosensor in angle interrogation method. the transfer matrix method (tmm) is used to analyze the characteristics of the device. results show that using ws2 in au/graphene structure increases sensitivity by about 12.64%, which is higher than mos2. combining graphene based spr and ellipsometry as a highly sensitive, label-free, real-time, and versatile method can be used to measure a very small concentration of biomolecules, which leads to 170-fold enhancement compared to angle interrogation method and improves the detection accuracy and quality factor.