Surface-enhanced Raman spectroscopy (SERS) has attracted increasing interest for chemical and biochemical sensing. Several studies have shown that SERS intensities are significantly increased when an optical interference substrate composed of a dielectric spacer and a reflector is used as a supporting substrate. However, the origin of this additional enhancement has not been systematically studied. In this paper, high sensitivity SERS substrates composed of self-assembled core-satellite nanostructures and silica-coated silicon interference layers have been developed. Their SERS enhancement is shown to be a function of the thickness of silica spacer on a more reflective silicon substrate. Finite difference time domain modeling is presented to show that the SERS enhancement is due to a spacer contribution via a sign change of the reflection coefficients at the interfaces. The magnitude of the local-field enhancement is defined by the interference of light reflected from the silica-air and silica-silicon interfaces, which constructively added at the hot spots providing a possibility to maximize intensity in the nanogaps between the self-assembled nanoparticles by changing the thickness of silica layer. The core-satellite assemblies on a 135 nm silica-coated silicon substrate exhibit a SERS activity of approximately 13 times higher than the glass substrate.

Phase controlled SERS enhancement / Zheng, Yuanhui; Rosa, Lorenzo; Thai, Thibaut; Ng, Soon Hock; Juodkazis, Saulius; Bach, Udo. - In: SCIENTIFIC REPORTS. - ISSN 2045-2322. - 9:1(2019), pp. 1-9. [10.1038/s41598-018-36491-0]

Phase controlled SERS enhancement

Rosa, Lorenzo;
2019

Abstract

Surface-enhanced Raman spectroscopy (SERS) has attracted increasing interest for chemical and biochemical sensing. Several studies have shown that SERS intensities are significantly increased when an optical interference substrate composed of a dielectric spacer and a reflector is used as a supporting substrate. However, the origin of this additional enhancement has not been systematically studied. In this paper, high sensitivity SERS substrates composed of self-assembled core-satellite nanostructures and silica-coated silicon interference layers have been developed. Their SERS enhancement is shown to be a function of the thickness of silica spacer on a more reflective silicon substrate. Finite difference time domain modeling is presented to show that the SERS enhancement is due to a spacer contribution via a sign change of the reflection coefficients at the interfaces. The magnitude of the local-field enhancement is defined by the interference of light reflected from the silica-air and silica-silicon interfaces, which constructively added at the hot spots providing a possibility to maximize intensity in the nanogaps between the self-assembled nanoparticles by changing the thickness of silica layer. The core-satellite assemblies on a 135 nm silica-coated silicon substrate exhibit a SERS activity of approximately 13 times higher than the glass substrate.
2019
24-gen-2019
9
1
1
9
Phase controlled SERS enhancement / Zheng, Yuanhui; Rosa, Lorenzo; Thai, Thibaut; Ng, Soon Hock; Juodkazis, Saulius; Bach, Udo. - In: SCIENTIFIC REPORTS. - ISSN 2045-2322. - 9:1(2019), pp. 1-9. [10.1038/s41598-018-36491-0]
Zheng, Yuanhui; Rosa, Lorenzo; Thai, Thibaut; Ng, Soon Hock; Juodkazis, Saulius; Bach, Udo
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11380/1169666
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