Metal-Dielectric-Graphene Hybrid Heterostructures with Enhanced Surface Plasmon Resonance Sensitivity Based on Amplitude and Phase Measurements

Abstract

Metal-dielectric-graphene hybrid heterostructures based on oxides Al2O3, HfO2, and ZrO2 as well as on complementary metal–oxide–semiconductor compatible dielectric Si3N4 covering plasmonic metals Cu and Ag have been fabricated and studied. We show that the characteristics of these heterostructures are important for surface plasmon resonance biosensing (such as minimum reflectivity, sharp phase changes, resonance full width at half minimum and resonance sensitivity to refractive index unit (RIU) changes) can be significantly improved by adding dielectric/graphene layers. We demonstrate maximum plasmon resonance spectral sensitivity of more than 30,000 nm/RIU for Cu/Al2O3 (ZrO2, Si3N4), Ag/Si3N4 bilayers and Cu/dielectric/graphene three-layers for near-infrared wavelengths. The sensitivities of the fabricated heterostructures were ~ 5–8 times higher than those of bare Cu or Ag thin films. We also found that the width of the plasmon resonance reflectivity curves can be reduced by adding dielectric/graphene layers. An unexpected blueshift of the plasmon resonance spectral position was observed after covering noble metals with high-index dielectric/graphene heterostructures. We suggest that the observed blueshift and a large enhancement of surface plasmon resonance sensitivity in metal-dielectric-graphene hybrid heterostructures are produced by stationary surface dipoles which generate a strong electric field concentrated at the very thin top dielectric/graphene layer.

Ternary Heterostructures Based on BaTiO3/MoO3/Ag for Highly Efficient and Reusable Photocatalytic Applications

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Label-free optical biosensing: going beyond the limits

“…Following this research, composite metaldielectric-graphene hybrid heterostructures were fabricated with plasmon resonances sensitivity of 30 000 nm RIU À1 . 131 Graphene and graphene oxide can also be used to improve the phase sensitivity of conventional gold SPR chips. This was done in the work Zeng et al 35 where the combination of graphene and a conventional gold film was used to achieve a high sensitivity.…”

“…Following this research, composite metal-dielectric-graphene hybrid heterostructures were fabricated with plasmon resonances sensitivity of 30 000 nm RIU −1 . 131…”

Atomically Thin Metal–Dielectric Heterostructures by Atomic Layer Deposition

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“…Due to the upsurge of exploring novel functionalities and continuously shrinking device sizes for 3D photonic integration, the investigation of various heterostructures, nanocomposites, and multilayers becomes increasingly demanding. Ultrathin metallic layers have been explored for applications in nanoelectronics, plasmonics, and photonics. − Metal–dielectric multilayer structures have revealed remarkable applications in enhancing optical nonlinearity, photocatalysis, hybrid waveguide in surface-enhanced Raman scattering, enhanced surface plasmon resonance, and ultrafast transport of plasmonic electrons, to name only a few.…”