Borophene and Phase Change Material-based Integrated Multilayered High-Sensitive Refractive Index Sensor for Infrared Frequency Spectrum

This work presents the design and numerical simulation of a multilayered surface plasmon resonance (SPR) sensor incorporating borophene and germanium (Ge)-antimony (Sb) telluride (Te) (GST) as active plasmonic materials. The sensor design is modelled in two dimensions (2D) and exhibits a broad refractive index detection range, from 1 to 2.5 µm/RIU. The proposed design utilizes a top-analyte configuration, where the target analyte is placed directly on the sensor surface for interaction. Various metals like Ag (silver), Au (gold), Al (aluminium), and Cu (copper) are considered for investigation of the influence of the middle metal layer on the overall optical response. The GST layer is modelled as a two-state material, accounting for its amorphous (aGST) and crystalline (cGST) phases. It allows for exploring the sensor’s tunability based on the GST material’s phase state. Furthermore, comprehensive optimization and validation processes are conducted for various device parameters, including layer thicknesses, widths, and the type of metal employed. These optimizations aim to achieve optimal sensor performance regarding sensitivity and overall functionality. Notably, the simulations reveal distinct bandwidths and resonant regions for both aGST and cGST phases of the GST layer. In conclusion, this proposed sensor provides potential application in biomolecular and chemical testing due to its tunable characteristics and broad refractive index detection range.