標題: Enhancing Surface Sensitivity of Nanostructure-Based Aluminum Sensors Using Capped Dielectric Layers
作者: Lee, Kuang-Li
Tsai, Po-Cheng
You, Meng-Lin
Pan, Ming-Yang
Shi, Xu
Ueno, Kosei
Misawa, Hiroaki
Wei, Pei-Kuen
應用化學系
Department of Applied Chemistry
公開日期: 1-Oct-2017
摘要: 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.
URI: http://dx.doi.org/10.1021/acsomega.7b01349
http://hdl.handle.net/11536/147862
ISSN: 2470-1343
DOI: 10.1021/acsomega.7b01349
期刊: ACS OMEGA
Volume: 2
Issue: 10
起始頁: 7461
結束頁: 7470
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