Sensitive hybrid plasmonic refractive index sensor based on Ag cross-grating nanoantenna and Au quantum dot upon SiO2 Nanowire

Şanlı A. K., KILIÇ V. T., Tabaru T. E.

Physica Scripta, cilt.101, sa.14, 2026 (SCI-Expanded) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 101 Sayı: 14
  • Basım Tarihi: 2026
  • Doi Numarası: 10.1088/1402-4896/ae5369
  • Dergi Adı: Physica Scripta
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Aerospace Database, Chemical Abstracts Core, Compendex, INSPEC, zbMATH
  • Anahtar Kelimeler: biosensing, FDTD simulation, field enhancement, nanoantenna, plasmonics, quantum dot, refractive index sensing
  • Abdullah Gül Üniversitesi Adresli: Evet

Özet

This study presents a distinctive hybrid plasmonic sensor architecture combining a silver (Ag) cross-shaped nanoantenna with a gold (Au) quantum dot (QD) for enhanced refractive index sensing applications. The structure consists of a silicon dioxide (SiO2) substrate and a cylindrically shaped SiO2 wire on it, topped with a silicon nitride (Si3N4) dielectric layer and an Ag cross grating, with an Au QD positioned at the center. Using free and open source 3D Finite-Difference Time-Domain (FDTD) simulations, exceptional electric field enhancement at the resonant wavelength of approximately 639–667 nm is demonstrated. The optimized structure achieves remarkable quality factors (Q-factors) exceeding 267 for biological media, representing among the highest reported values for plasmonic sensing structures. Unlike conventional red-shift sensors, our design exhibits a distinctive blue-shift sensing behavior arising from hybrid plasmonic mode coupling, achieving sensitivities ranging from 190 to 344 nm RIU−1 for various analytes, including water, blood, PDMS, body fat, ethanol, and glass. The ultrasharp resonances (FWHM ∼2.3 nm) combined with intense field enhancement make this design highly suitable for biosensing applications.