Sensitivity-Enhanced Surface Plasmon Resonance Sensor with Bimetal/ Tungsten Disulfide (WS2)/MXene (Ti3C2Tx) Hybrid Structure

This work aims at improving the sensitivity of a surface plasmon resonance (SPR) sensor with the BK7 prism, silver/gold (Ag/Au) bimetallic films, 2D materials tungsten disulfide (WS2), and MXene (Ti3C2Tx) under angular interrogation technique. The proposed SPR sensor is a free space structure using the Kretschmann configuration to stimulate surface plasmons (SPs). The finite-difference time-domain (FDTD) method is used to analyze the optical behavior of the proposed SPR sensor. The thickness of the bimetallic layers and the number of layers of 2D materials are optimized to obtain maximum sensitivity for various sensing medium refractive indices ranging from 1.33 to 1.335 RIU. The maximum sensitivity of 348 deg/RIU is obtained with a thickness of 33 nm Ag, a thickness of 15 nm Au and with monolayer WS2, and four layers of Ti3C2Tx MXene at 633 nm. This excellent performance of the proposed structure makes it suitable for detecting biomolecules and other analytes.