Enhancing Surface Sensitivity of Nanostructure-Based Aluminum Sensors Using Capped Dielectric Layers

Pei Kuen Wei, Hiroaki Misawa, Kosei Ueno, Xu Shi, Ming-Yang Pan, Meng-Lin You, Po-Cheng Tsai, Kuang Li Lee

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

The studies of nanostructure-based aluminum sensors have attracted huge attention because aluminum is a more cost-effective plasmonic material. However, the intrinsic properties of the aluminum metal, having a large imaginary part of the dielectric function and a longer electromagnetic field decay length and problems of poor long-term chemical stability, limit the surface-sensing capability and applicability of nanostructures. We propose the combination of capped aluminum nanoslits and a thin-capped dielectric layer to overcome these limitations. We show that the dielectric layer can positively enhance the wavelength sensitivities of the Wood's anomaly-dominant resonance and asymmetric Fano resonance in capped aluminum nanoslits. The maximum improvement can be reached by a factor of 3.5. Besides, there is an optimal layer thickness for the surface sensitivity because of the trade-off relationship between the refractive index sensitivity and decay length. We attribute the enhanced surface sensitivity to a reduced evanescent length, which is confirmed by the finite difference time-domain calculations. The protein-protein interaction experiments verify the high-surface sensitivity of the structures, and a limit of quantification (LOQ) of 1 pg/mL antibovine serum albumin is achieved. Such low-cost, highly sensitive aluminum-based nanostructures can benefit various sensing applications.
Original languageEnglish
Pages (from-to)7461-7470
Number of pages10
JournalACS Omega
Volume2
Issue number10
DOIs
StatePublished - Oct 2017

Keywords

  • PLASMON RESONANCE SENSORS; GOLD NANOSLIT ARRAYS; NANOHOLE ARRAYS; FANO RESONANCES; LIGHT TRANSMISSION; INTEGRATION METHOD; BIOSENSORS; FILMS; METAMATERIALS; CRYSTALS

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