Metal film-coupled nano-island surface-enhanced Raman scattering substrate and preparation method thereof

Abstract

The invention provides a metal film coupling nano-island surface-enhanced Raman scattering substrate. The metal film coupling nano-island surface-enhanced Raman scattering substrate comprises a substrate chip, wherein an aluminum film layer, a metal film layer allowing aluminum element to penetrate through, an aluminum oxide layer and a noble metal nano-island layer are sequentially arranged on the substrate chip from bottom to top. Due to the fact that the noble metal nano-island layer has a local-area electromagnetic field enhancement effect, Raman scattering light can be enhanced, meanwhile, a nano cavity which is similar to a fabry-perot waveguide cavity can be formed between the metal film layer on the upper layer of the aluminum film layer and the noble metal nano-island layer, and thus Raman scattering can be further enhanced; and the substrate with the structure can change the scattered light distribution of molecules, and the Raman signal collection efficiency is further improved. The enhancement factor of the substrate can reach 10<8>, and the substrate is far superior to substrate material of an existing traditional metal nano-island SERS; and the surface of the metal film layer forms an ultra-thin Al2O3 packaging layer, so that the service life of the substrate material is greatly prolonged, and the stability of the substrate is improved.

Description

technical field [0001] The invention relates to the field of chemical analysis and detection, in particular to a metal film-coupled nano-island surface-enhanced Raman scattering substrate and a preparation method thereof. Background technique [0002] Surface-enhanced Raman scattering (surface-enhanced Raman scattering, SERS) is an abnormal surface optical phenomenon, which refers to the enhancement of Raman scattering spectrum signals of molecules adsorbed on the surface of rough noble metals under the excitation of incident light. a phenomenon. The SERS phenomenon is closely related to the surrounding environment of the molecules to be detected. The SERS active substrate with high enhancement ability and high stability is one of the key factors to realize high-sensitivity detection by using the amplification effect of SERS. [0003] The preparation of SERS substrates has been greatly developed in recent years. Metal nano-islands prepared by dewetting metal films also have...

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Problems solved by technology

However, the traditional metal nano-island SERS substrate still has the following two problems: (1) Metal nano-islands are limited by their forming principles, and it is difficult to control the interval between nano-islands in a small range, so its SERS enhancement (2) It is generally necessary to use gold, silver and other precious metal nanostructures as high-sensitivity reinforcement materials, and most metal nanostructures are prone to oxidation and corrosion. The life of the base material is extremely limited

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