Preparation method of surface enhanced Raman substrate with semiconductor oxide nanoparticles modified noble metal nanocone array structure
By combining microelectronic manufacturing process and chemical synthesis, a SERS substrate with semiconductor oxide nanoparticles modified with precious metal nanocone array structure was prepared, which solved the problem of cumbersome and high cost in the preparation process of existing solid SERS substrates, and realized that High sensitivity, low cost SERS substrate, suitable for environmental monitoring and food safety inspection.
Patent Information
- Application Number
- CN202210180299.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-02-25
- Publication Date
- 2024-12-17
- Estimated Expiration
- 2042-02-25
AI Technical Summary
The preparation process of existing solid SERS substrates is cumbersome, poor morphological structure uniformity, difficult to prepare in large areas, difficult to control costs, and the resolution of portable Raman spectroscopy is low and difficult to meet actual detection needs.
Combining microelectronic manufacturing process and chemical synthesis method, the precious metal nanocone array structure is first prepared, and then the semiconductor ZnO nanoparticles are uniformly loaded on its surface. The nanocone array is prepared by low-temperature inductive coupled plasma etching technology, magnetron sputtering or thermal evaporation. Precious metal films were plated and ZnO nanoparticles were prepared by lifting and impregnation.
A SERS substrate with high sensitivity, good repeatability and low cost is obtained. Combined with electromagnetic enhancement and charge transfer chemical enhancement effects, it is suitable for environmental monitoring and fast trace detection of food safety.
Smart Images
Figure CN114720448B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the intersecting field of microelectronic micro-nano manufacturing technology and chemical synthesis technology, and in particular to a method for preparing a surface enhanced Raman substrate of a semiconductor oxide nanoparticle-modified noble metal nanocone array structure. Background Art
[0002] Raman spectroscopy is a relatively mature identification method that can quickly analyze the molecular structure and composition of substances. SERS technology has been widely used in research fields such as label-free detection, materials science, biochemistry, biomedicine, electrochemistry, and molecular imaging due to its advantages such as fast detection, sensitivity, non-destructive analysis, and small sample amount required. It has shown great advantages in trace detection, analysis, and monitoring of chemical substances such as pesticides and additives in food.
[0003] Compared with traditional trace substance detection methods such as electrochemical analysis, high performance liquid chromatography, gas chromatography-mass spectrometry, etc., portable Raman spectrometers have become more popular candidates for on-site real-time detection because they do not require complex pretreatment of the analyte, have a short analysis cycle, are inexpensive and easy to carry. However, the resolution of portable Raman spectra is relatively low and it is difficult to meet the actual detection needs. Therefore, it is very important to prepare a stable and highly sensitive SERS substrate and use it in conjunction with a portable Raman spectrometer to form an industry application solution. According to the search and investigation, the Raman enhancement products used on the market include liquid nanoparticle substrates and solid substrate chips. Liquid nanoparticles are prone to agglomeration and unevenness, and have a short shelf life. Compared with solid SERS substrates, they have better repeatability and long-term stability. In recent years, many companies such as Renishaw, Ocean Optics, and Silmeco have launched solid SERS chips, but these chips limit the application scenarios, have high detection costs, and need to improve quantitative detection capabilities. It is particularly important to prepare low-cost solid SERS substrates with uniform and controllable micromorphology that can be used for quantitative analysis and trace detection. This is also one of the key basic scientific issues that many international scientists have been working hard on in recent years for SERS applications.
[0004] At present, the preparation method of solid SERS substrates, microelectronic manufacturing physical methods, are easier to achieve large-area preparation, and the substrate morphology is uniform and controllable; the commonly used chemical synthesis method also has significant advantages in regulating the size and morphology of nanostructures. For example, patent CN201910345971.2 reported the preparation of zinc oxide nanorod structures loaded with Au nanoparticles as SERS substrates by combining hydrothermal and electrochemical synthesis methods; the paper [Anal.Chem.2021,93,3403-10] reported the preparation of zinc oxide nanoparticle-modified Ag nanosheet SERS substrates using a solution synthesis method, which showed excellent SERS activity in the Raman enhanced detection of benzodiazepine drugs. Although this type of precious metal and semiconductor composite nanostructure SERS substrate exhibits a good Raman enhancement effect, the preparation process mentioned is cumbersome and time-consuming, the morphological structure is poorly uniform and regular, large-area preparation is difficult, and the cost is difficult to effectively control.
[0005] In order to solve the above technical problems, the present invention combines microelectronic manufacturing technology and chemical synthesis method. The first step is to prepare a noble metal nanocone array structure, and the second step is to uniformly load semiconductor ZnO nanoparticles on the nano noble metal cones to form a solid SERS substrate with controllable structure and morphology. The SERS substrate couples the electromagnetic enhancement of noble metals and the charge transfer chemical enhancement of semiconductors. The prepared SERS substrate has the effects of large area, low cost, high repeatability, excellent sensitivity, and simple preparation method. The preparation of the SERS substrate shows important scientific research significance and practical application value. Summary of the invention
[0006] The purpose of the present invention is to provide a method for preparing a surface enhanced Raman substrate of a semiconductor oxide nanoparticle modified noble metal nanocone array structure. The SERS substrate prepared by the method has high sensitivity, good repeatability, simple preparation method, uniform morphology and low cost.
[0007] The present invention provides a method for preparing a surface enhanced Raman substrate of a semiconductor oxide nanoparticle-modified noble metal nanocone array structure, which comprises:
[0008] The first step is to prepare a substrate of a nanocone array structure;
[0009] The second step is to deposit a layer of noble metal film with a thickness of nanometers on the surface of the nanocone array structure;
[0010] The third step is to monodisperse load a layer of semiconductor oxide nanoparticles on the surface of the noble metal nanocones.
[0011] The first step is further specifically to etch the silicon wafer using low-temperature inductively coupled plasma enhanced reactive ion etching technology to obtain a large-area high-density nanocone array structure silicon wafer substrate.
[0012] Wherein, in the first step, the reaction gases used for etching are SF6 and O2.
[0013] Among them, in the first step, the etching reaction pressure is 0.5-10 Pa, the reaction power is 20-80 W, the reaction gas SF6 flow rate is 20-80 sccm, the O2 flow rate is 5-15 sccm, and the etching time is 15-120 s.
[0014] Wherein, in the second step, the nanometer-thick precious metal film is formed by magnetron sputtering or thermal evaporation.
[0015] The noble metal in the second step can be any one of gold and silver, and the thickness of the noble metal film is 15 to 60 nm.
[0016] Wherein, in the third step, the semiconductor oxide nanoparticles are prepared by a pulling and impregnation method, and the semiconductor oxide is preferably ZnO.
[0017] Among them, the steps of synthesizing ZnO by the pulling and impregnation method used in the third step include: first preparing a zinc acetate dihydrate and aluminum nitrate ethanol solution with a molar ratio of 1:1, mixing them evenly at room temperature, and heating them at 70°C under magnetic stirring for 60 minutes; then immersing the above-mentioned noble metal nanocone substrate in the above-mentioned solution for 15 to 60 seconds, then pulling out the noble metal nanocone substrate at a pulling rate of 6000 μm / s, and drying it at 50 to 80°C for 5 to 20 minutes, repeating the above-mentioned pulling and drying process 2 to 6 times; finally annealing at 400°C for 30 minutes.
[0018] Beneficial effects of the present invention
[0019] The present invention provides a preparation method of a SERS substrate with a semiconductor oxide ZnO nanoparticle-modified noble metal nanocone array structure, which combines micro-nano processing maskless silicon etching, noble metal nanolayer deposition and chemical synthesis technology, and the process steps are greatly simplified compared with traditional photolithography methods. The obtained SERS substrate has low cost and uniform and controllable morphology, and simultaneously couples the electromagnetic enhancement of the noble metal and the charge transfer chemical enhancement effect of the semiconductor. The obtained high-sensitivity SERS substrate is expected to be practically applied in the fields of environmental monitoring, food safety and public safety rapid trace detection. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 Process flow chart for preparing SERS substrate with ZnO nanoparticle modified noble metal nanocone array structure. DETAILED DESCRIPTION
[0021] The present invention provides a method for preparing a surface enhanced Raman substrate having a semiconductor oxide nanoparticle-modified noble metal nanocone array structure, which comprises:
[0022] The first step is to prepare a substrate of a nanocone array structure;
[0023] The second step is to deposit a layer of noble metal film with a thickness of nanometers on the surface of the nanocone array structure;
[0024] The third step is to prepare semiconductor oxide nanoparticles, which are monodispersed and loaded on the surface of the nanocone array structure. 。 -
[0025] The first step is further specifically to use low-temperature inductively coupled plasma enhanced reactive ion etching technology (ICP-RIE) to perform maskless etching on the silicon wafer to obtain a large-area high-density nanocone array structure substrate.
[0026] In the first step, the reaction gases used for etching are SF6 and O2, the reaction pressure is 0.5-10Pa, the reaction power is 20-80W, the reaction gas SF6 flow rate is 20-80sccm, the O2 flow rate is 5-15sccm, and the etching time is 15-120s.
[0027] In the second step, the nanometer-thick precious metal film is formed by magnetron sputtering or thermal evaporation.
[0028] The noble metal in the second step can be any one of gold and silver, and the thickness of the noble metal film is 15-60 nm.
[0029] In the third step, the semiconductor oxide nanoparticles are prepared by a pulling and impregnation chemical method, and the semiconductor oxide is preferably ZnO.
[0030] Among them, the steps of synthesizing ZnO by the pulling and impregnation method used in the third step include: first preparing a zinc acetate dihydrate and aluminum nitrate ethanol solution with a molar ratio of 1:1, mixing them evenly at room temperature, and heating them at 70°C under magnetic stirring for 60 minutes; then immersing the above-mentioned noble metal nanocone substrate in the above-mentioned solution for 15 to 60 seconds, then pulling out the noble metal nanocone substrate at a pulling rate of 6000 μm / s, and drying it at 50 to 80°C for 5 to 20 minutes, repeating the above-mentioned pulling and drying process 2 to 6 times; finally annealing at 400°C for 30 minutes.
[0031] The following embodiments are used to explain the implementation methods of the present invention in detail, so that the implementation process of how the present invention applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.
[0032] Embodiment 1
[0033] (1) Select a 4-inch silicon wafer and prepare a concentrated H2SO4:H2O2 mixed cleaning solution. Immerse the silicon wafer in the solution and cook it at 120°C for 2 hours to remove oil and other contaminants on the surface of the silicon wafer. Rinse with ultrapure water and blow dry with N2 for later use.
[0034] (2) The cleaned silicon wafer surface is etched without mask by ICP-RIE technology. The reaction gases used are SF6 and O2. The reaction gas flow rate of SF6 is 60 sccm, the flow rate of O2 is 10 sccm, the reaction pressure is 1 Pa, the reaction power is 30 W, and the etching time is 60 s.
[0035] (3) A 50 nm thick gold film was coated on the nano-silicon cone array structure using magnetron sputtering technology at a pressure of 2 Pa, a DC power of 20 W, an Ar flow rate of 50 sccm, and a time of 30 s.
[0036] (4) ZnO nanoparticles were synthesized by the pulling and impregnation method. First, 4.390 g of zinc acetate dihydrate and 3.7512 g of aluminum nitrate were weighed and dissolved in 100 mL of ethanol solution. After mixing evenly at room temperature, the mixture was heated at 70 °C for 60 min under magnetic stirring. Then, the noble metal nanocone substrate was immersed in the solution for 30 s, and then the noble metal nanocone substrate was pulled out at a pulling rate of 6000 μm / s and dried at 70 °C for 10 min. The pulling and drying process was repeated 4 times. Finally, the SERS substrate with ZnO nanoparticles modified with noble metal nanocone array structure was obtained.
[0037] The whole process is as follows Figure 1 shown.
[0038] Embodiment 2
[0039] The preparation method of the ZnO nanoparticle modified noble metal nanocone array structure SERS substrate of Example 2 is the same as that of Example 1, except that: in Example 1 (2), ICP-RIE technology is used to perform maskless etching on the cleaned silicon wafer surface, and SF6 and O2 are used as reaction gases. The reaction gas SF6 flow rate is 30sccm, the O2 flow rate is 10sccm, the reaction pressure is 1Pa, the reaction power is 50W, and the etching time is 60s to obtain large-area nano silicon cone array structures with different densities.
[0040] All of the above are primary implementations of this intellectual property and do not set limitations on other forms of implementation of this new product and / or new method. Those skilled in the art will use this important information and modify the above content to achieve similar implementations. However, all modifications or transformations based on the new product of this invention belong to the reserved rights.
[0041] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any technician familiar with the profession may use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.
Claims
1. A method for preparing a surface enhanced Raman substrate with a semiconductor oxide nanoparticle-modified noble metal nanocone array structure, characterized in that: include: The first step is to prepare a nanocone array structure substrate; The first step is to etch the silicon wafer using low-temperature inductively coupled plasma enhanced reactive ion etching technology to obtain a large-area high-density nanocone array structure silicon wafer substrate; The second step is to deposit a layer of noble metal film with a thickness of nanometers on the surface of the nanocone array structure to obtain a noble metal nanocone array structure; The third step is to prepare semiconductor oxide nanoparticles, which are monodisperse loaded on the surface of the noble metal nanocone array structure. In the third step, semiconductor oxide nanoparticles are prepared by a pulling and impregnation chemical method, and the semiconductor oxide is ZnO. The steps of synthesizing ZnO include: first, preparing a zinc acetate dihydrate and aluminum nitrate ethanol solution with a molar ratio of 1:1, mixing them evenly at room temperature, and heating them at 70°C under magnetic stirring for 60 min; then immersing the noble metal nanocone array structure in the above solution for 15-60 s, and then pulling out the noble metal nanocone array structure at a pulling rate of 6000 μm / s, and drying it at 50-80°C for 5-20 min, and repeating the above pulling and drying process 2-6 times; finally, annealing at 400°C for 30 min.
2. The method for preparing a surface enhanced Raman substrate with a semiconductor oxide nanoparticle-modified noble metal nanocone array structure according to claim 1, characterized in that: In the first step, the reaction gases used for etching are SF6 and O2.
3. The method for preparing a surface enhanced Raman substrate with a semiconductor oxide nanoparticle-modified noble metal nanocone array structure according to claim 1, characterized in that: In the first step, the etching reaction pressure is 0.5~10 Pa, the reaction power is 20~80 W, the reaction gas SF6 flow rate is 20~80 sccm, the O2 flow rate is 5~15 sccm, and the etching time is 15~120 s.
4. The method for preparing a surface enhanced Raman substrate with a semiconductor oxide nanoparticle-modified noble metal nanocone array structure according to claim 1, characterized in that: In the second step, the nanometer-thick noble metal film is formed by magnetron sputtering or thermal evaporation.
5. The method for preparing a surface enhanced Raman substrate with a semiconductor oxide nanoparticle-modified noble metal nanocone array structure according to claim 1, characterized in that: The precious metal in the second step is any one of gold or silver, and the thickness of the precious metal film is 15-60 nm.
6. A surface enhanced Raman substrate having a semiconductor oxide nanoparticle-modified noble metal nanocone array structure prepared by the preparation method according to any one of claims 1 to 5.