TY - GEN
T1 - Experimental study of sensitivity enhancement in SPR biosensors by use of zinc oxide intermediary layers
AU - Chiu, Nan Fu
AU - Singh, Amit
AU - Nelson-Fitzpatrick, Nathan
AU - Dutt, Sarang
AU - Evoy, Stephane
AU - Lin, Chii Wann
PY - 2011
Y1 - 2011
N2 - 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.
AB - 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.
KW - Angular interrogation mode
KW - Biosensor
KW - Full Width at Half-Maximum (FWHM)
KW - Intensity interrogation mode
KW - Intermediary layer
KW - Refractive index unit (RIU)
KW - Surface plasmon resonance (SPR)
KW - Zinc oxide (ZnO)
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M3 - Conference contribution
AN - SCOPUS:81455143975
SN - 9781439871386
T3 - Technical Proceedings of the 2011 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2011
SP - 86
EP - 89
BT - Technical Proceedings of the 2011 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2011
T2 - Nanotechnology 2011: Electronics, Devices, Fabrication, MEMS, Fluidics and Computational - 2011 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2011
Y2 - 13 June 2011 through 16 June 2011
ER -