Enhanced refractive index sensing using a surface plasmon resonance sensor with heterostructure

This article aims to enhance the sensitivity of a surface plasmon resonance sensor for refractive index sensing in the visible region using a low refractive index prism. The proposed sensing system is ultrasensitive and employs an angular interrogation method for measuring reflected intensity. The bimetallic layers and two-dimensional heterostructure are utilized to increase sensitivity. Black phosphorus is utilized as an analyte-interacting layer due to its sp(3) hybridized puckered structure, high charge carrier density, indirect bandgap and larger surface area for attachment of analyte. To optimize the sensor structure and architecture based on its sensitivity and figure of merit, a comprehensive analysis is performed. The proposed sensor achieves the best possible sensitivity of 345.83 degrees/RIU, detection accuracy of 0.132 Deg(-1) and figure of merit of 45.74/RIU. This work enables to design a highly sensitive refractive index sensor useful to sense small sized analyte. The proposed research work provides new dimension to develop highly sensitive refractive index sensor for biomolecule or biochemical sensing.