Preparation method of surface-enhanced Raman scattering substrate

Abstract

The invention discloses a preparation method of a surface-enhanced Raman scattering substrate. The preparation method comprises the following steps: preparing a densely-arranged single-layer nano microsphere two-dimensional colloidal crystal layer on a SiO2 / Si (001) substrate; reducing the diameters of the nano microspheres; depositing a layer of metal film on the surface of the sample; strippingthe microsphere two-dimensional colloidal crystal layer; etching the SiO2 layer by adopting a dry method; etching the Si (001) substrate by adopting a wet method to form an inverted pyramid structure;stripping the SiO2 and the metal mask layer by using an etchant solution to obtain a Si template with an inverted pyramid structure; preparing a noble metal film on the Si template; transferring thenoble metal film to a new substrate by using an adhesive, wherein the pyramid structure is exposed; and transferring a layer of graphene on the surface of the precious metal pyramid. According to themethod disclosed by the invention, the pyramid type SERS substrate is successfully prepared by using two methods of colloid photoetching and micro-nano processing; the prepared substrate is uniform innano pyramid structure distribution in a large-scale range, and has high sensitivity and universality.

Description

technical field [0001] The invention belongs to the technical field of preparation of micro-nano structures, in particular to a preparation method of a surface-enhanced Raman scattering substrate. Background technique [0002] Due to the high sensitivity and unique molecular fingerprint information of surface-enhanced Raman spectroscopy, a large number of related studies have been carried out in recent years. According to the World Health Organization, as of 2015, the top ten causes of death include neurological diseases, diabetes, cardiovascular diseases, cancer and viral diseases. Most diseases start with small changes in the state of the cells, where the altered substances occur in very low concentrations; based on this, surface-enhanced Raman has great advantages in the early detection of diseases. [0003] After decades of development, the application of surface-enhanced Raman scattering (SERS) technology in biosensing and early detection of diseases has made great pro...

AI Technical Summary

Problems solved by technology

Compared with the above two methods, metal nanoparticles on solid substrates have the advantages of low cost, easy large-scale preparation, and high sensitivity, but the uniformity is poor, and the synthesis parameters need to be precisely controlled

Micro-nanofabrication methods can achieve better uniformity, more regular shapes and more ordered arrays, thereby improving the reproducibility of SERS; but it is still difficult to achieve universal testing of analytes of different sizes

Among them, the open hotspots of the nanopyramid SERS substrate have the potential to detect molecules of different scales, but it is still very difficult to achieve large-scale uniformity while maintaining low cost.

If electron beam lithography is used, the cost of preparing large area substrates is very high

For SERS substrates with non-solid substrates, such as metal nanoparticle dispersions, there are shortcomings of sparse and random distribution of hot spots, and thus in highly diluted solutions, the probability that the molecules to be tested and the hot spots coincide is very low

In addition, the label-based indirect SERS method has the inevitable false positive problem

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