High Sensitive Biosensors Based on the Coupling Between Surface Plasmon Polaritons on Titanium Nitride and a Planar Waveguide Mode

Abstract

High sensitivity biosensors based on the coupling of surface plasmon polaritons on titanium nitride (TiN) and a planar waveguide mode were built; they were proved by sensing three different media: air, water and dried egg white; sensors described here could be useful for sensing materials with a refractive index between 1.0 and 1.6; in particular, materials of biological interest with a refractive index in the range 1.3–1.6, like those containing biotin and/or streptavidin. They were built by depositing Nb2O5/SiO2/TiN multilayer structures on the flat surface of D-shaped sapphire prisms by using the dc magnetron sputtering technique. Attenuated total reflection (ATR) experiments in the Kretschmann configuration were accomplished for the air/TiN/Prism and S/Nb2O5/SiO2/TiN/Prism structures, S being the sample or sensing medium. ATR spectra for plasmons at the TiN/air interface showed a broad absorption band for angles of incidence between 36 and 85°, with full width at half maximum (FWHM) of approximately 40°. For the S/Nb2O5/SiO2/TiN/Prism structures, ATR spectra showed a sharp reflectivity peak, within the broad plasmonic absorption band, which was associated with Fano resonances. The angular position and FWHM of the Fano resonances strongly depend on the refractive index of the sensing medium. ATR spectra were fitted by using the transfer-matrix method. Additionally, we found that angular sensitivity and figure of merit increase with increasing the refractive index of the sensing medium.

Synthesis of Plasmonically Active Titanium Nitride Using a Metallic Alloy Buffer Layer Strategy

“…The dip in the reflectance spectra, shown in Figure a, relates to the excitation of SPPs at the TiN/air interface. , The calculated reflectance spectrum is in good agreement with the experimental responses as shown in Figure a. The broadening in all the spectra is very common and it can be attributed to the low carrier mobility (electrons) due to the larger absorptivity of TiN films than conventional plasmonic materials such as Au and Ag . A slight mismatch between the calculated and experimentally acquired spectra can be understood as follows: a 2 nm seed layer of Cr 90 Ru 10 is used to fabricate TiN thin films suitable for reflectance measurements.…”

“…The broadening in all the spectra is very common and it can be attributed to the low carrier mobility (electrons) due to the larger absorptivity of TiN films than conventional plasmonic materials such as Au and Ag. 66 A slight mismatch between the calculated and experimentally acquired spectra can be understood as follows: a 2 nm seed layer of Cr 90 Ru 10 is used to fabricate TiN thin films suitable for reflectance measurements. As Cr 90 Ru 10 is optically absorptive, it may cause such a discrepancy and distort some of the coupling capabilities of TiN.…”

Enhanced fluorescence of CsPbBr3/ZnO heterojunction enabled by titanium nitride nanoparticles

“…The enhanced fluorescence was due to the transfer of photo-generated carriers through carrier diffusion, as well as the trap and electron conductor effects of TiN. Owing to the existence of surface plasmons in the surface state of the TiN NPs, [29,55] the hot electrons of the higher E C of the CsPbBr 3 QDs with higher E C were directly swept and transferred to the E C in the defect state of the ZnO film. Only a small fraction of the electrons fell and recombined with holes.…”

Surface Plasmon Resonance (SPR)-Based Biosensors as Instruments with High Versatility and Sensitivity

“…In the works [12][13][14], the improvement of sensitivity of SPR-based sensors was under intensive investigation. In [12], the authors used gold nanowires (AuNW) in order to increase the sensitivity of LSPR-based optical fiber refractive index sensor and optimized its parameters.…”

“…Production of a large-area MoS 2 monolayer helped to limit oxidation of silver film and, as the authors demonstrated theoretically and experimentally, served to improve the sensitivity of SPR sensor [13]. In the work [14], the authors built up and investigated characteristics, primarily sensitivity, of SPR-based sensors constructed via deposition of multilayer (Nb 2 O 5 /SiO 2 /TiN) structures on the flat surface of D-shaped prism.…”