Titanium dioxide/zinc telluride/aluminium antimonide-assisted label-free plasmonic sensor for early detection of glucose in urine

Abstract The article presents a high multi-layered surface plasmon resonance (SPR) sensor for the detection of glucose in urine. This designed sensor consists of a K108 (LZOS) prism, a silver (Ag) layer, and dielectric layers of titanium dioxide (\(\:{TiO}_{2}\)), zinc telluride (ZnTe), and aluminium antimonide (AlSb) to enhance plasmonic resonance and analyte interaction. The optical response is modeled using the transfer matrix method (TMM) along with angular interrogation at a wavelength of 633 nm. The concentration of glucose in urine affects owns its refractive index (RI), varying from 1.335 (non-diabetic) to 1.347 (highly diabetic). The numerical simulations based on the TMM revealed a maximum sensitivity of 416.42°/RIU and a quality factor of 142.28 RIU⁻¹, a signal to noise ratio of 1.707, figure of merit of 129.07 and combined sensitivity factor of 91.18, indicating the high resolution and sharp resonance characteristics. The results show that the integration of dielectric and semiconducting materials is significantly enhanced by the plasmonic behavior, giving significant improvement over traditional SPR biosensors. The standard fabrication steps for designing the proposed structure is shown at the end.