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High-sensitivity plasmonic biosensor based on a graphene-SiO₂ hybrid structure

XIANGDONG YI1,* , TIANGUI HUANG1, RENLONG ZHOU1, JUNMING LAO1

Affiliation

  1. School of Physics and Information Engineering, Guangdong University of Education, Guangzhou 510303, China

Abstract

This study presents the design and analysis of a highly sensitive surface plasmon resonance (SPR) biosensor based on a graphene-SiO2 hybrid structure. Utilizing a prism-coupled configuration, the sensor incorporates a SiO2 dielectric layer and a few-layer graphene film deposited on a gold film to substantially enhance the localized electromagnetic field and biomolecule capture efficiency at the sensing interface. The effects of key structural parameters—including the number of graphene layers, SiO2 thickness, and gold film thickness—on sensor performance were systematically investigated. An optimized sensitivity of 220°/RIU was achieved with a five-layer graphene configuration at an analyte refractive index of 1.39, representing a 175% improvement over conventional SPR sensors. Electromagnetic field analysis revealed that localized field enhancement near the graphene edges is the primary mechanism driving this sensitivity improvement. The proposed sensor exhibits excellent responsiveness and stability across a broad refractive index range of 1.33–1.39, providing a high-performance platform for precise biochemical detection.

Keywords

Surface Plasmon Resonance (SPR), Biosensor, Graphene, SiO₂, Sensitivity.

Citation

XIANGDONG YI, TIANGUI HUANG, RENLONG ZHOU, JUNMING LAO, High-sensitivity plasmonic biosensor based on a graphene-SiO₂ hybrid structure, Optoelectronics and Advanced Materials - Rapid Communications, 20, 7-8, July-August 2026, pp.371-377 (2026).

Submitted at: April 19, 2026

Accepted at: Aug. 3, 2026