Experimental study of sensitivity enhancement in SPR biosensors by use of zinc oxide intermediary layers

Nan Fu Chiu, Amit Singh, Nathan Nelson-Fitzpatrick, Sarang Dutt, Stephane Evoy, Chii Wann Lin

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We report a novel design for the intermediary layer of surface plasmon resonance (SPR) devices that use high refractive index and high-transmittance zinc oxide (ZnO) dielectric layers to enhance the signal quality and improve the full width at half-maximum (FWHM) of the reflectivity curve. We optimized the design of ZnO thin films using different sputtering parameters and performed analytical comparisons with conventional intermediary layers of chromium (Cr) as well as indium tin oxide (ITO). The study is based on application of the Fresnel equation, which provides an explanation and verification for the observed SPR narrow-width curve and optical transmittance spectra displayed by (ZnO/Au)-1, (Cr/Au)-4 and (ITO/Au)-5 devices. On exposure to ethanol, the (ZnO/Au)-1 device showed a two-fold decrease in FWHM and a 4.5-fold larger shift in intensity interrogation. The (ZnO/Au)-1 device exhibits a wider linearity range and much higher sensitivity. They also exhibit a good linear relationship between angle and concentration dependence in the tested range. We show that these advances represent a novel and simple method for preparing high-sensitivity, high-resolution SPR biosensors for accurate and specific bio-molecular detection.

Original languageEnglish
Title of host publicationTechnical Proceedings of the 2011 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2011
Pages86-89
Number of pages4
Publication statusPublished - 2011 Nov 23
EventNanotechnology 2011: Electronics, Devices, Fabrication, MEMS, Fluidics and Computational - 2011 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2011 - Boston, MA, United States
Duration: 2011 Jun 132011 Jun 16

Publication series

NameTechnical Proceedings of the 2011 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2011
Volume3

Other

OtherNanotechnology 2011: Electronics, Devices, Fabrication, MEMS, Fluidics and Computational - 2011 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2011
CountryUnited States
CityBoston, MA
Period11/6/1311/6/16

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Keywords

  • Angular interrogation mode
  • Biosensor
  • Full Width at Half-Maximum (FWHM)
  • Intensity interrogation mode
  • Intermediary layer
  • Refractive index unit (RIU)
  • Surface plasmon resonance (SPR)
  • Zinc oxide (ZnO)

ASJC Scopus subject areas

  • Bioengineering
  • Biomedical Engineering
  • Electrical and Electronic Engineering

Cite this

Chiu, N. F., Singh, A., Nelson-Fitzpatrick, N., Dutt, S., Evoy, S., & Lin, C. W. (2011). Experimental study of sensitivity enhancement in SPR biosensors by use of zinc oxide intermediary layers. In Technical Proceedings of the 2011 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2011 (pp. 86-89). (Technical Proceedings of the 2011 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2011; Vol. 3).