WO2023100610A1 - Method for producing surface enhanced substrate and surface enhanced spectroscopy - Google Patents

Method for producing surface enhanced substrate and surface enhanced spectroscopy Download PDF

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Publication number
WO2023100610A1
WO2023100610A1 PCT/JP2022/041744 JP2022041744W WO2023100610A1 WO 2023100610 A1 WO2023100610 A1 WO 2023100610A1 JP 2022041744 W JP2022041744 W JP 2022041744W WO 2023100610 A1 WO2023100610 A1 WO 2023100610A1
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metal film
enhanced substrate
enhanced
immersion step
concentration
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PCT/JP2022/041744
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French (fr)
Japanese (ja)
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芳弘 丸山
遼太郎 石川
一彦 藤原
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浜松ホトニクス株式会社
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
    • G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
    • G01N21/65—Raman scattering

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  • the present disclosure relates to a method of producing a surface-enhanced substrate that generates an enhanced electric field, and a method of performing surface-enhanced spectroscopy using this surface-enhanced substrate.
  • SERS surface enhanced Raman scattering
  • SEIRA surface enhanced infrared absorption
  • SPF surface plasmon excitation enhanced fluorescence
  • a dispersion liquid in which nanometer-order sized metal colloids are dispersed is used as the metal microstructure, or a nanometer-order sized microstructure is used.
  • a surface-enhanced substrate is used in which a metal film having on its surface is formed on the surface of a support (see Patent Documents 1 to 3).
  • the metal colloid or metal film preferably contains a metal such as silver (Ag), gold (Au), copper (Cu) or platinum (Pt) that can enhance the electric field.
  • the enhanced electric field reaches It is important that a large number of specimens constantly exist in the immediate vicinity of the metal microstructure to be measured.
  • the metal colloidal dispersion and the surface-enhanced substrate are desired to improve the effect of enhancing the electric field in the metal microstructure and to improve the adsorption number of the analyte to the metal microstructure.
  • the metal colloidal dispersion production methods have been proposed with the intention of achieving more sensitive analysis, but none of the production methods are easy.
  • An embodiment of the present invention is a surface-enhanced substrate fabrication method.
  • the method for producing a surface-enhanced substrate includes (1) a metal film forming step of forming a metal film containing silver or gold on the surface of a support; or an immersion step of fabricating a surface-enhanced substrate in which the microstructure of the surface of the metal film is modified by immersion in an aqueous electrolyte solution containing halogen ions.
  • a surface-enhanced substrate preparation method comprises immersing a surface-enhanced substrate having a metal film containing silver or gold formed on the surface of a support and having microstructures on the surface of the metal film in an aqueous electrolyte solution containing acid or halogen ions. , to fabricate a surface-enhanced substrate in which the microstructure of the surface of the metal film is modified.
  • An embodiment of the present invention is a surface-enhanced spectroscopy method.
  • the sample is analyzed using the surface-enhanced substrate produced by the surface-enhanced substrate-producing method having the above configuration.
  • FIG. 1 is a flow chart for explaining a method for producing a surface-enhanced substrate.
  • FIG. 2 is a diagram showing the height distribution of the metal film of the surface-enhanced substrate after the metal film forming step S3 (before the immersion step S4).
  • FIG. 3 is a diagram three-dimensionally showing the height distribution of the metal film of the surface-enhanced substrate after the metal film formation step S3 (before the immersion step S4).
  • FIG. 4 is a diagram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of HCl (concentration 5 mM) for 2 hours in the immersion step S4.
  • FIG. 1 is a flow chart for explaining a method for producing a surface-enhanced substrate.
  • FIG. 2 is a diagram showing the height distribution of the metal film of the surface-enhanced substrate after the metal film forming step S3 (before the immersion step S4).
  • FIG. 3 is a diagram three-dimensionally
  • FIG. 5 is a diagram three-dimensionally showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of HCl (concentration 5 mM) for 2 hours in the immersion step S4.
  • FIG. 6 is a diagram showing the height distribution of the metal film after immersing the surface-enhanced substrate in an aqueous solution of HNO 3 (concentration 5 mM) for 2 hours in the immersion step S4.
  • FIG. 7 is a diagram three-dimensionally showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous HNO 3 solution (concentration 5 mM) for 2 hours in the immersion step S4.
  • FIG. 5 is a diagram three-dimensionally showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous HNO 3 solution (concentration 5 mM) for 2 hours in the immersion step S4.
  • FIG. 8 is a diagram showing the height distribution of the metal film after immersing the surface-enhanced substrate in an aqueous solution of H 2 SO 4 (concentration 5 mM) for 2 hours in the immersion step S4.
  • FIG. 9 is a diagram three-dimensionally showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of H 2 SO 4 (concentration 5 mM) for 2 hours in the immersion step S4.
  • FIG. 10 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate was immersed in aqueous solutions of HCl, HNO 3 and H 2 SO 4 (concentration 5 mM) for 2 hours in the immersion step S4. be.
  • FIG . 9 is a diagram three-dimensionally showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of H 2 SO 4 (concentration 5 mM) for 2 hours in the immersion step S4.
  • FIG. 11 shows p- mercaptobenzoic acid ( p- MBA) is a graph showing the results of measuring the Raman shift.
  • FIG. 12 is a graph showing the results of measuring the Raman shift of p-MBA as a test sample using the surface-enhanced substrate immersed in an aqueous solution of HCl (concentration 0.01 mM to 5 mM) for 2 hours in the immersion step S4. is.
  • FIG. 13 shows the Raman shift of 4,4′-bipyridyl (4BP) as an analyte using a surface-enhanced substrate immersed in an aqueous solution of H 2 SO 4 (concentration 1 mM or 5 mM) for 2 hours in the immersion step S4.
  • 4,4′-bipyridyl (4BP) 4,4′-bipyridyl
  • FIG. 14 is a diagram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of NaCl (concentration: 5 mM) for 2 hours in the immersion step S4.
  • FIG. 15 is a diagram three-dimensionally showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of NaCl (concentration: 5 mM) for 2 hours in the immersion step S4.
  • FIG. 16 is a diagram showing the height distribution of the metal film after immersing the surface-enhanced substrate in an aqueous NaBr solution (concentration: 5 mM) for 2 hours in the immersion step S4.
  • FIG. 14 is a diagram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of NaCl (concentration: 5 mM) for 2 hours in the immersion step S4.
  • FIG. 15 is a diagram three-dimensionally showing the height distribution of the metal film
  • FIG. 17 is a diagram three-dimensionally showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of NaBr (concentration: 5 mM) for 2 hours in the immersion step S4.
  • FIG. 18 is a diagram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous NaI solution (concentration: 5 mM) for 2 hours in the immersion step S4.
  • FIG. 19 is a diagram three-dimensionally showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous NaI solution (concentration: 5 mM) for 2 hours in the immersion step S4.
  • FIG. 20 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in aqueous solutions of NaCl, NaBr and NaI (concentration 5 mM) for 2 hours in the immersion step S4.
  • FIG. 21 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of HCl (concentration 5 mM) for 2 minutes or 2 hours in the immersion step S4.
  • FIG. 22 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of NaCl (concentration: 5 mM) for 2 minutes or 2 hours in the immersion step S4.
  • FIG. 23 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate was immersed in an aqueous solution of NaCl (concentrations of 0.01 mM, 1 mM, and 100 mM) for 2 hours in the immersion step S4. be.
  • FIG. 24 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of NaCl (concentration 1000 mM or 5000 mM) for 2 hours in the immersion step S4.
  • FIG. 25 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous NaBr solution (concentration of 1 mM, 10 mM, or 100 mM) for 2 hours in the immersion step S4.
  • FIG. 26 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous NaI solution (concentration of 1 mM or 10 mM) for 2 hours in the immersion step S4.
  • FIG. 27 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate was immersed in an aqueous solution of NaI (concentration 0.01 mM) for 2 minutes, 5 minutes, or 120 minutes in the immersion step S4.
  • FIG. 28 is an enlarged view of a part of FIG. 27.
  • FIG. FIG. 29 is a graph showing the results of measuring the Raman shift of p-MBA as a specimen using the surface-enhanced substrate immersed in an aqueous solution of HCl (concentration 20 mM) for 2 hours in the immersion step S4.
  • FIG. 30 is a graph showing the results of measuring the Raman shift of p-MBA as a specimen using the surface-enhanced substrate immersed in an aqueous solution of H 2 SO 4 (concentration 1000 mM) for 2 hours in the immersion step S4. be.
  • FIG. 31 is a graph showing the results of measuring the Raman shift of p-MBA as a specimen using a surface-enhanced substrate immersed in an aqueous solution of HNO 3 (concentration 100 mM) for 2 hours in the immersion step S4.
  • FIG. 32 is a graph showing the results of measuring the Raman shift of p-MBA as a specimen using a surface-enhanced substrate immersed in an aqueous NaCl solution (concentration: 2000 mM) for 2 hours in the immersion step S4.
  • FIG. 33 is a graph showing the results of measuring the Raman shift of p-MBA as a specimen using a surface-enhanced substrate immersed in an aqueous solution of NaBr (concentration 1 mM) for 2 hours in the immersion step S4.
  • FIG. 34 is a graph showing the results of measuring the Raman shift of 4BP as a specimen using the surface-enhanced substrate immersed in an aqueous solution of HCl (concentration 20 mM) for 2 hours in the immersion step S4.
  • FIG. 35 is a graph showing the results of measuring the Raman shift of 4BP as a specimen using the surface-enhanced substrate immersed in an aqueous solution of H 2 SO 4 (concentration 1000 mM) for 2 hours in the immersion step S4.
  • FIG. 36 is a graph showing the results of measuring the Raman shift of 4BP as an analyte using the surface-enhanced substrate immersed in an aqueous HNO 3 solution (concentration 100 mM) for 2 hours in the immersion step S4.
  • FIG. 37 is a graph showing the results of measuring the Raman shift of 4BP as a specimen using the surface-enhanced substrate immersed in an aqueous NaCl solution (concentration: 2000 mM) for 2 hours in the immersion step S4.
  • FIG. 38 is a graph showing the results of measuring the Raman shift of 4BP as a specimen using the surface-enhanced substrate immersed in an aqueous solution of NaBr (concentration 1 mM) for 2 hours in the immersion step S4.
  • FIG. 39 is a graph showing the results of measuring the Raman shift of 4BP as a specimen using the surface-enhanced substrate immersed in an aqueous solution of NaI (concentration 0.01 mM) for 2 minutes in the immersion step
  • FIG. 1 is a flow chart explaining the surface-enhanced substrate manufacturing method.
  • a support preparing step S1 a base layer forming step S2, a metal film forming step S3, an immersion step S4, a washing step S5, and a drying step S6 are sequentially performed to form a nanometer-order microstructure. is formed on the surface of a support to prepare a surface-enhanced substrate.
  • a support on which a metal film is to be formed on the surface in the metal film formation step S3 is prepared.
  • the material of the support is arbitrary, such as a metal or a semiconductor, but a material that is difficult to dissolve in the subsequent immersion step S4 is preferable.
  • the shape of the support is also arbitrary, but a flat plate shape is preferred in consideration of the ease of the subsequent base layer forming step S2 and metal film forming step S3. Also, it is preferable to wash the support (in particular, the surface on which the metal film is to be formed in the subsequent metal film forming step S3).
  • the surface of the support may be smooth, but preferably has a nanometer-order microstructure.
  • the support may be obtained by simply cutting out a predetermined material into a predetermined shape, or may be obtained by forming a microstructure on the surface after that.
  • microstructures formed on the surface of the support include, for example, microstructures made of ZnO nanorods or boehmite.
  • ZnO nanorods are crystals of zinc oxide (ZnO) grown in a columnar shape.
  • Boehmite is an aluminum hydrated oxide film with a crystalline structure.
  • a base layer is formed on the surface of the support.
  • the underlayer enhances the adhesion of the metal film (the metal film to be formed on the surface of the support in the subsequent metal film forming step S3) to the surface of the support.
  • the material of the underlayer may be arbitrary, but preferably includes a metal such as titanium (Ti), chromium (Cr) or nickel (Ni).
  • the underlying layer is formed by vapor deposition, for example.
  • the thickness of the underlayer may be, for example, several nanometers to several tens of nanometers.
  • the underlayer may be a thin film having an island structure.
  • a metal film is formed on the surface of the support.
  • Materials for the metal film include metals capable of enhancing an electric field, such as silver (Ag), gold (Au), copper (Cu) or platinum (Pt), and preferably include Ag or Au.
  • a metal film is formed by vapor deposition, for example. Note that the metal film may be formed by a vapor deposition method (for example, sputtering) other than vapor deposition.
  • the thickness of the metal film is arbitrary, and may be several nanometers to several hundreds of nanometers.
  • the surface of the metal film (the surface opposite to the support side) generally has a nanometer order immediately after formation by vapor deposition or the like, even if the support surface or the underlying layer does not have a microstructure. It has a microstructure with a size of When the support surface or the underlying layer has a microstructure, the surface of the metal film can have a microstructure corresponding to the microstructure of the support surface or the underlying layer.
  • the support on which the metal film was formed in the metal film formation step S3 is immersed in an aqueous electrolyte solution to fabricate a surface-enhanced substrate in which the microstructure of the surface of the metal film is modified.
  • the aqueous electrolyte solution used here is an aqueous solution containing acid or halogen ions.
  • aqueous solution containing acid an aqueous solution containing hydrochloric acid (HCl), sulfuric acid (H 2 SO 4 ), nitric acid (HNO 3 ), or the like is used.
  • aqueous solution containing halogen ions an aqueous solution containing chlorine ions (Cl ⁇ ), bromide ions (Br ⁇ ), iodine ions (I ⁇ ), or the like is used.
  • Modification of the microstructure on the surface of the metal film involves changing the distribution of the height of the microstructure on the surface of the metal film (height relative to the surface of the support), or changing the peak height position of the microstructure on the surface of the metal film. Including changing intervals, etc.
  • the immersion step S4 can be performed at room temperature. No voltage application is required during the immersion step S4. Moreover, it is not necessary to supply metal ions during the immersion step S4.
  • the surface-enhanced substrate produced in the immersion step S4 is washed with a clean liquid to wash away the electrolyte aqueous solution used in the immersion step S4.
  • the liquid used for cleaning is selected from liquids that do not dissolve the metal film, and is preferably pure water, ethanol, or the like.
  • the surface-enhanced substrate cleaned in the cleaning step S5 is dried.
  • the surface-enhanced substrate may be dried by blowing clean gas (for example, nitrogen gas or rare gas) onto the surface-enhanced substrate.
  • the support preparation step S1 when preparing a support made of silicon (Si), the support is boiled and washed with an aqueous solution of sodium peroxodisulfate (concentration: 0.015 g/mL) for 20 minutes. rinse with pure water and dry.
  • the support preparation step S1 when forming a microstructure of ZnO nanorods on the surface of a support made of Si, a base layer is formed on the support surface, and then Ag or Au is deposited as a seed layer. Then, an aqueous solution of zinc nitrate hexahydrate and an aqueous solution of sodium hydroxide are mixed, and the support is immersed in this mixed solution and heated. dry.
  • the support preparation step S1 when forming a microstructure of boehmite on the surface of a support made of Si, aluminum (Al) is vacuum-deposited on the surface of the support to form an Al layer, and the support is boiled pure. After being immersed in water, the support taken out is rinsed with pure water and dried by blowing nitrogen gas.
  • a vacuum vapor deposition method (resistance board heating method) is used to form a Ti underlayer on the surface of a flat support made of Si.
  • the degree of vacuum is set to 1 to 2 ⁇ 10 ⁇ 5 Torr, and the deposition rate is set to about 0.01 nm/sec.
  • a vacuum vapor deposition method (resistance board heating method) is used.
  • the degree of vacuum is set to 1 to 2 ⁇ 10 ⁇ 5 Torr, and the deposition rate is set to about 0.02 nm/sec.
  • the base layer forming step S2 may not be performed.
  • the surface-enhanced substrate is subjected to the immersion step S4 and subsequent steps. By performing the treatment, it is possible to produce a surface-enhanced substrate in which the microstructure of the surface of the metal film is modified.
  • the surface-enhanced substrate produced as described above is used in surface-enhanced spectroscopy methods such as SERS spectroscopy, SEIRA spectroscopy, and SPF spectroscopy.
  • SERS spectroscopy SEIRA spectroscopy
  • SPF spectroscopy SPF spectroscopy
  • an enhanced electric field photon field
  • the subject can be analyzed with high sensitivity.
  • the surface-enhanced substrate was obtained by forming an underlying layer of Ti with a thickness of about 3 nm on the surface of a support made of Si, and further forming a metal film of Ag with a thickness of about 10 nm.
  • FIG. 2 and 3 are diagrams showing the height distribution of the metal film of the surface-enhanced substrate after the metal film formation step S3 (before the immersion step S4).
  • FIG. 2 shows the height (thickness) of the metal film at each position in the xy plane with the two directions parallel to the support surface and perpendicular to each other as the x axis and the y axis.
  • FIG. 3 three-dimensionally shows the height (thickness) of the metal film at each position on the xy plane, with the thickness (height) direction of the metal film as the z-axis.
  • the surface of the metal film of the surface-enhanced substrate after the metal film formation step S3 (before the immersion step S4) has a microstructure.
  • FIGS. 4 and 5 are diagrams showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of HCl (concentration 5 mM) for 2 hours in the immersion step S4.
  • FIG. 4 shows the height (thickness) of the metal film at each position on the xy plane in shading.
  • FIG. 5 three-dimensionally shows the height (thickness) of the metal film at each position on the xy plane.
  • FIG. 6 and 7 are diagrams showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of HNO 3 (concentration 5 mM) for 2 hours in the immersion step S4.
  • FIG. 6 shows the height (thickness) of the metal film at each position on the xy plane with shading.
  • FIG. 7 three-dimensionally shows the height (thickness) of the metal film at each position on the xy plane.
  • FIG. 8 and 9 are diagrams showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of H 2 SO 4 (concentration 5 mM) for 2 hours in the immersion step S4.
  • FIG. 8 shows the height (thickness) of the metal film at each position on the xy plane in shading.
  • FIG. 9 three-dimensionally shows the height (thickness) of the metal film at each position on the xy plane.
  • the microstructure of the surface of the metal film was modified after the immersion step S4 compared to before the immersion step S4 (FIGS. 2 and 3). Moreover, the degree of modification of the microstructure on the surface of the metal film varied depending on the type of acid used.
  • FIG. 10 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate was immersed in aqueous solutions of HCl, HNO 3 and H 2 SO 4 (concentration 5 mM) for 2 hours in the immersion step S4. be. This figure also shows the height distribution of the metal film after the metal film forming step S3 (before the immersion step S4).
  • the microstructure of the surface of the metal film of the surface-enhanced substrate is modified after the immersion step S4 compared to before the immersion step S4, and the height histogram is shifted to the right (higher). increasing).
  • the effect was highest with HCl followed by H 2 SO 4 .
  • the surface-enhanced substrate was obtained by forming a microstructure of ZnO nanorods on the surface of a support made of Si, and further forming a metal film made of Ag with a thickness of about 50 nm.
  • the wavelength of the laser light used was 785 nm
  • the laser light intensity was 3.4 mW
  • Raman spectrum measurement was performed 100 times over 1 second and the average value was taken.
  • FIG . 11 shows p- mercaptobenzoic acid ( 4- It is a graph which shows the result of having measured the Raman shift of mercaptobenzoic acid (p-MBA). This figure also shows the results when using the surface-enhanced substrate after the metal film formation step S3 (before the immersion step S4).
  • the surface-enhanced substrate was washed with pure water in the cleaning step S5, and dried by blowing nitrogen gas in the drying step S6. After this surface-enhanced substrate was immersed in a p-MBA ethanol solution (concentration: 1 mM) for 2 hours, the surface-enhanced substrate was taken out, rinsed with ethanol, and dried by blowing nitrogen gas.
  • the Raman scattering intensity is higher in the case of using the surface-enhanced substrate after the immersion step S4 than in the case of using the surface-enhanced substrate before the immersion step S4.
  • the effect was highest with HCl followed by H 2 SO 4 .
  • FIG. 12 is a graph showing the results of measuring the Raman shift of p-MBA as a test sample using the surface-enhanced substrate immersed in an aqueous solution of HCl (concentration 0.01 mM to 5 mM) for 2 hours in the immersion step S4. is. This figure also shows the results when using the surface-enhanced substrate after the metal film formation step S3 (before the immersion step S4).
  • the HCl concentration in the immersion step S4 is set to each value in the range of 0.01 mM to 5 mM, the surface-enhanced substrate is washed with pure water in the cleaning step S5, and the surface-enhanced substrate is dried by blowing nitrogen gas in the drying step S6.
  • the surface-enhanced substrate was immersed in a p-MBA ethanol solution (concentration: 1 mM) for 2 hours, the surface-enhanced substrate was taken out, rinsed with ethanol, and dried by blowing nitrogen gas.
  • FIG . 13 shows 4,4′-bipyridyl (4,4′- It is a graph which shows the result of having measured the Raman shift of bipyridyl:4BP). This figure also shows the results when using the surface-enhanced substrate after the metal film formation step S3 (before the immersion step S4).
  • the H 2 SO 4 concentration in the immersion step S4 was set to 1 mM or 5 mM, the surface-enhanced substrate was washed with pure water in the washing step S5, and dried by blowing nitrogen gas in the drying step S6. After this surface-enhanced substrate was immersed in a 4BP aqueous solution (concentration: 10 ⁇ M) for 30 minutes, the surface-enhanced substrate was taken out, rinsed with pure water, and dried by blowing nitrogen gas.
  • the specimen could be analyzed with higher sensitivity.
  • the surface-enhanced substrate was obtained by forming an underlying layer of Ti with a thickness of about 3 nm on the surface of a support made of Si, and further forming a metal film of Ag with a thickness of about 10 nm.
  • FIG. 14 and 15 are diagrams showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of NaCl (concentration 5 mM) for 2 hours in the immersion step S4.
  • FIG. 14 shows the height (thickness) of the metal film at each position on the xy plane in shading.
  • FIG. 15 three-dimensionally shows the height (thickness) of the metal film at each position on the xy plane.
  • FIG. 16 and 17 are diagrams showing the height distribution of the metal film after the surface-enhanced substrate was immersed in an aqueous solution of NaBr (concentration 5 mM) for 2 hours in the immersion step S4.
  • FIG. 16 shows the height (thickness) of the metal film at each position on the xy plane with shading.
  • FIG. 17 three-dimensionally shows the height (thickness) of the metal film at each position on the xy plane.
  • FIG. 18 and 19 are diagrams showing the height distribution of the metal film after the surface-enhanced substrate was immersed in an aqueous NaI solution (concentration 5 mM) for 2 hours in the immersion step S4.
  • FIG. 18 shows the height (thickness) of the metal film at each position on the xy plane with shading.
  • FIG. 19 three-dimensionally shows the height (thickness) of the metal film at each position on the xy plane.
  • the microstructure of the surface of the metal film was modified after the immersion step S4 compared to before the immersion step S4 (FIGS. 2 and 3). Also, the degree of modification of the microstructure on the surface of the metal film varied depending on the type of halogen ion used.
  • FIG. 20 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate was immersed in aqueous solutions (concentration 5 mM) of NaCl, NaBr, and NaI for 2 hours in the immersion step S4. This figure also shows the height distribution of the metal film after the metal film forming step S3 (before the immersion step S4).
  • the microstructure of the surface of the metal film of the surface-enhanced substrate is modified after the immersion step S4 compared to before the immersion step S4, and the height histogram is shifted to the right (higher). increasing).
  • the effect was highest with NaCl, followed by NaBr.
  • FIG. 21 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of HCl (concentration 5 mM) for 2 minutes or 2 hours in the immersion step S4.
  • FIG. 22 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of NaCl (concentration: 5 mM) for 2 minutes or 2 hours in the immersion step S4.
  • These figures also show the height distribution of the metal film after the metal film formation step S3 (before the immersion step S4).
  • the microstructure of the surface of the metal film was obtained by immersing the surface-enhanced substrate for 2 minutes in both the HCl aqueous solution and the NaCl aqueous solution in the immersion step S4. could be modified. The effect of the modification was greater when using an aqueous solution of HCl.
  • FIG. 23 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate was immersed in an aqueous solution of NaCl (concentrations of 0.01 mM, 1 mM, and 100 mM) for 2 hours in the immersion step S4. be.
  • concentration of halogen ions the more the height histogram shifted to the right (in the direction of increasing height).
  • the surface-enhanced substrate was obtained by forming an underlying layer of Ti with a thickness of about 3 nm on the surface of a support made of Si, and further forming a metal film of Au with a thickness of about 5 nm.
  • the aqueous solutions used in the immersion step S4 were aqueous solutions of HCl, HNO 3 , H 2 SO 4 , NaCl, NaBr and NaI. Also, the concentration of the aqueous solution used in the immersion step S4 was varied, and the immersion time was also varied.
  • FIG. 24 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of NaCl (concentration 1000 mM or 5000 mM) for 2 hours in the immersion step S4.
  • FIG. 25 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous NaBr solution (concentration of 1 mM, 10 mM, or 100 mM) for 2 hours in the immersion step S4.
  • FIG. 26 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous NaI solution (concentration of 1 mM or 10 mM) for 2 hours in the immersion step S4.
  • FIG. 27 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate was immersed in an aqueous solution of NaI (concentration 0.01 mM) for 2 minutes, 5 minutes, or 120 minutes in the immersion step S4.
  • . 28 is an enlarged view of a part of FIG. 27.
  • FIG. These figures also show the height distribution of the metal film after the metal film formation step S3 (before the immersion step S4).
  • the height histogram of the metal film made of Au shifts to the right (in the direction of height increase) regardless of the use of each of the aqueous solutions of NaCl, NaBr, and NaI in the immersion step S4. bottom. Also, the higher the concentration of halogen ions, the greater the shift of the height histogram to the right (in the direction of increasing height).
  • the surface-enhanced substrate was obtained by forming a fine structure of boehmite with a thickness of about 500 nm on the surface of a support made of Si, and further forming a metal film of Au with a thickness of about 20 nm.
  • the wavelength of the laser light used was 785 nm, the laser light intensity was 3.4 mW, and the average value was obtained by performing 100 Raman spectrum measurements over 1 second.
  • p-MBA and 4BP were used as test subjects.
  • FIG. 29 is a graph showing the results of measuring the Raman shift of p-MBA as a specimen using the surface-enhanced substrate immersed in an aqueous solution of HCl (concentration 20 mM) for 2 hours in the immersion step S4.
  • FIG. 30 is a graph showing the results of measuring the Raman shift of p-MBA as a specimen using the surface-enhanced substrate immersed in an aqueous solution of H 2 SO 4 (concentration 1000 mM) for 2 hours in the immersion step S4. be.
  • FIG. 31 is a graph showing the results of measuring the Raman shift of p-MBA as a specimen using a surface-enhanced substrate immersed in an aqueous solution of HNO 3 (concentration 100 mM) for 2 hours in the immersion step S4.
  • FIG. 32 is a graph showing the results of measuring the Raman shift of p-MBA as a specimen using a surface-enhanced substrate immersed in an aqueous NaCl solution (concentration: 2000 mM) for 2 hours in the immersion step S4.
  • FIG. 33 is a graph showing the results of measuring the Raman shift of p-MBA as a specimen using a surface-enhanced substrate immersed in an aqueous solution of NaBr (concentration 1 mM) for 2 hours in the immersion step S4. These figures also show the results when using the surface-enhanced substrate after the metal film formation step S3 (before the immersion step S4).
  • p-MBA as an analyte could be analyzed with higher sensitivity.
  • FIG. 34 is a graph showing the results of measuring the Raman shift of 4BP as a specimen using the surface-enhanced substrate immersed in an aqueous solution of HCl (concentration 20 mM) for 2 hours in the immersion step S4.
  • FIG. 35 is a graph showing the results of measuring the Raman shift of 4BP as a specimen using the surface-enhanced substrate immersed in an aqueous solution of H 2 SO 4 (concentration 1000 mM) for 2 hours in the immersion step S4.
  • FIG. 36 is a graph showing the results of measuring the Raman shift of 4BP as an analyte using the surface-enhanced substrate immersed in an aqueous HNO 3 solution (concentration 100 mM) for 2 hours in the immersion step S4.
  • FIG. 37 is a graph showing the results of measuring the Raman shift of 4BP as an analyte using the surface-enhanced substrate immersed in an aqueous NaCl solution (concentration: 2000 mM) for 2 hours in the immersion step S4.
  • FIG. 38 is a graph showing the results of measuring the Raman shift of 4BP as a specimen using the surface-enhanced substrate immersed in an aqueous solution of NaBr (concentration 1 mM) for 2 hours in the immersion step S4.
  • FIG. 39 is a graph showing the results of measuring the Raman shift of 4BP as a specimen using the surface-enhanced substrate immersed in an aqueous solution of NaI (concentration 0.01 mM) for 2 minutes in the immersion step S4.
  • These figures also show the results when using the surface-enhanced substrate after the metal film formation step S3 (before the immersion step S4).
  • the surface-enhanced substrate can also be used for other surface-enhanced spectroscopy methods (eg, SEIRA spectroscopy, SPF spectroscopy, etc.).
  • SEIRA spectroscopy SEIRA spectroscopy
  • SPF spectroscopy etc.
  • an enhanced electric field photon field
  • the subject can be analyzed with high sensitivity.
  • the surface-enhanced substrate manufacturing method and the surface-enhanced spectroscopy method are not limited to the above-described embodiments and configuration examples, and various modifications are possible.
  • the method for producing a surface-enhanced substrate according to the above embodiment includes (1) a metal film forming step of forming a metal film containing silver or gold on the surface of a support; an immersion step of immersing the body in an aqueous electrolyte solution containing acid or halogen ions to fabricate a surface-enhanced substrate having a modified microstructure on the surface of the metal film.
  • the above surface-enhanced substrate manufacturing method may further include a support preparation step of preparing a support having a microstructure on the surface on which the metal film is to be formed.
  • the method for producing a surface-enhanced substrate may further include, prior to the metal film forming step, an underlayer forming step of forming on the surface of the support an underlayer that enhances the adhesion of the metal film to the surface of the support. .
  • the method for producing a surface-enhanced substrate includes placing a surface-enhanced substrate having a metal film containing silver or gold on the surface of a support and having microstructures on the surface of the metal film in an aqueous electrolyte solution containing acid or halogen ions.
  • the immersion produces a surface-enhanced substrate in which the microstructure of the surface of the metal film is modified.
  • the surface-enhanced spectroscopy method analyzes a subject using the surface-enhanced substrate produced by the surface-enhanced substrate production method having the above configuration.
  • the present invention can be used as a method for easily producing a surface-enhanced substrate that enables more sensitive analysis, and as a surface-enhanced spectroscopic method for highly sensitive analysis of a subject using the surface-enhanced substrate. is.
  • S1 Support preparation step
  • S2 Base layer forming step
  • S3 Metal film forming step
  • S4 Immersion step
  • S5 washing step
  • S6 Drying step.

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Abstract

A method for producing a surface enhanced substrate according to the present invention produces a surface enhanced substrate wherein a metal film having a surface that is provided with a microstructure having a size of the order of nanometers is formed on the surface of a supporting body by sequentially performing a supporting body preparation step S1, a base layer formation step S2, a metal film formation step S3, an immersion step S4, a cleaning step S5 and a drying step S6. In the metal film formation step S3, a metal film containing silver or gold is formed on the surface of a supporting body. In the immersion step S4, the supporting body, on which the metal film has been formed in the metal film formation step S3, is immersed in an acid or an aqueous electrolyte solution containing halogen ions, thereby forming a surface enhanced substrate in which the microstructure of the surface of the metal film is modified. Consequently, the present invention achieves a method which is capable of easily producing a surface enhanced substrate that enables an analysis with higher sensitivity.

Description

表面増強基板作製方法および表面増強分光方法Surface-enhanced substrate preparation method and surface-enhanced spectroscopy method
　本開示は、増強された電場を発生させる表面増強基板を作製する方法、および、この表面増強基板を用いて表面増強分光を行う方法に関するものである。 The present disclosure relates to a method of producing a surface-enhanced substrate that generates an enhanced electric field, and a method of performing surface-enhanced spectroscopy using this surface-enhanced substrate.
　表面増強ラマン散乱（Surface　Enhanced　Raman　Scattering：ＳＥＲＳ）分光、表面増強赤外吸収（Surface　Enhanced　Infrared　Absorption：ＳＥＩＲＡ）分光、および表面プラズモン励起増強蛍光（Surface　Plasmon　Field-enhanced　Fluorescence：ＳＰＦ）分光等による表面増強分光方法が知られている。このような表面増強分光方法では、光が照射された金属微小構造体において増強された電場（光子場）を発生させ、その金属微小構造体の近傍に存在する被検体と光との相互作用（ラマン散乱、吸収、蛍光、等）を検出することにより、被検体を高感度に分析することができる。 Surface enhancement by surface enhanced Raman scattering (SERS) spectroscopy, surface enhanced infrared absorption (SEIRA) spectroscopy, and surface plasmon excitation enhanced fluorescence (SPF) spectroscopy Spectroscopic methods are known. In such a surface-enhanced spectroscopy method, an enhanced electric field (photon field) is generated in a metal microstructure irradiated with light, and an interaction ( By detecting Raman scattering, absorption, fluorescence, etc.), the analyte can be analyzed with high sensitivity.
　これらの表面増強分光方法において、増強された電場を発生させるために、金属微小構造体としてナノメートルオーダーのサイズの金属コロイドが分散した分散液が用いられ、或いは、ナノメートルオーダーのサイズの微小構造を表面に有する金属膜が支持体の表面に形成された表面増強基板が用いられる（特許文献１～３を参照）。金属コロイドや金属膜は、好適には銀（Ａｇ）、金（Ａｕ）、銅（Ｃｕ）または白金（Ｐｔ）等の電場増強効果を奏し得る金属を含む。 In these surface-enhanced spectroscopic methods, in order to generate an enhanced electric field, a dispersion liquid in which nanometer-order sized metal colloids are dispersed is used as the metal microstructure, or a nanometer-order sized microstructure is used. A surface-enhanced substrate is used in which a metal film having on its surface is formed on the surface of a support (see Patent Documents 1 to 3). The metal colloid or metal film preferably contains a metal such as silver (Ag), gold (Au), copper (Cu) or platinum (Pt) that can enhance the electric field.
特開２０１１－０３３５１８号公報JP 2011-033518 A 特開２０１２－２１１８３９号公報JP 2012-211839 A 国際公開第２０１４／０２５０２６号WO2014/025026
　上記の表面増強分光方法において高感度分析を実現する為には、光が照射された金属微小構造体において増強された電場（光子場）を発生させることに加えて、その増強された電場が到達する金属微小構造体のごく近傍に定常的に多くの被検体が存在することが重要である。 In order to achieve high-sensitivity analysis in the above surface-enhanced spectroscopy method, in addition to generating an enhanced electric field (photon field) in the metal microstructure irradiated with light, the enhanced electric field reaches It is important that a large number of specimens constantly exist in the immediate vicinity of the metal microstructure to be measured.
　したがって、金属コロイド分散液および表面増強基板は、金属微小構造体における電場増強効果の向上が望まれるとともに、金属微小構造体における被検体の吸着数の向上が望まれる。金属コロイド分散液については、より高感度な分析を意図した作製方法が提案されているが、何れの作製方法も容易でない。 Therefore, the metal colloidal dispersion and the surface-enhanced substrate are desired to improve the effect of enhancing the electric field in the metal microstructure and to improve the adsorption number of the analyte to the metal microstructure. As for the metal colloidal dispersion, production methods have been proposed with the intention of achieving more sensitive analysis, but none of the production methods are easy.
　本発明は、より高感度な分析が可能な表面増強基板を容易に作製することができる方法を提供することを目的とする。また、本発明は、表面増強基板を用いて被検体を高感度に分析することができる表面増強分光方法を提供することを目的とする。 An object of the present invention is to provide a method for easily producing a surface-enhanced substrate that enables more sensitive analysis. Another object of the present invention is to provide a surface-enhanced spectroscopy method capable of highly sensitively analyzing a subject using a surface-enhanced substrate.
　本発明の実施形態は、表面増強基板作製方法である。表面増強基板作製方法は、（１）銀または金を含む金属膜を支持体の表面に形成する金属膜形成工程と、（２）金属膜形成工程において金属膜が形成された支持体を、酸またはハロゲンイオンを含む電解質水溶液に浸漬することで、金属膜の表面の微小構造が改質された表面増強基板を作製する浸漬工程と、を備える。 An embodiment of the present invention is a surface-enhanced substrate fabrication method. The method for producing a surface-enhanced substrate includes (1) a metal film forming step of forming a metal film containing silver or gold on the surface of a support; or an immersion step of fabricating a surface-enhanced substrate in which the microstructure of the surface of the metal film is modified by immersion in an aqueous electrolyte solution containing halogen ions.
　本発明の他の実施形態は、表面増強基板作製方法である。表面増強基板作製方法は、銀または金を含む金属膜が支持体の表面に形成され該金属膜の表面に微小構造を有する表面増強基板を、酸またはハロゲンイオンを含む電解質水溶液に浸漬することで、金属膜の表面の微小構造が改質された表面増強基板を作製する。 Another embodiment of the present invention is a surface-enhanced substrate fabrication method. A surface-enhanced substrate preparation method comprises immersing a surface-enhanced substrate having a metal film containing silver or gold formed on the surface of a support and having microstructures on the surface of the metal film in an aqueous electrolyte solution containing acid or halogen ions. , to fabricate a surface-enhanced substrate in which the microstructure of the surface of the metal film is modified.
　本発明の実施形態は、表面増強分光方法である。表面増強分光方法は、上記構成の表面増強基板作製方法により作製された表面増強基板を用いて被検体の分析を行う。 An embodiment of the present invention is a surface-enhanced spectroscopy method. In the surface-enhanced spectroscopy method, the sample is analyzed using the surface-enhanced substrate produced by the surface-enhanced substrate-producing method having the above configuration.
　本発明の実施形態によれば、より高感度な分析が可能な表面増強基板を容易に作製することができる。 According to the embodiments of the present invention, surface-enhanced substrates capable of more sensitive analysis can be easily produced.
図１は、表面増強基板作製方法を説明するフローチャートである。FIG. 1 is a flow chart for explaining a method for producing a surface-enhanced substrate. 図２は、金属膜形成工程Ｓ３後（浸漬工程Ｓ４前）の表面増強基板の金属膜の高さ分布を濃淡で示す図である。FIG. 2 is a diagram showing the height distribution of the metal film of the surface-enhanced substrate after the metal film forming step S3 (before the immersion step S4). 図３は、金属膜形成工程Ｓ３後（浸漬工程Ｓ４前）の表面増強基板の金属膜の高さ分布を３次元的に示す図である。FIG. 3 is a diagram three-dimensionally showing the height distribution of the metal film of the surface-enhanced substrate after the metal film formation step S3 (before the immersion step S4). 図４は、浸漬工程Ｓ４においてＨＣｌの水溶液（濃度５ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布を濃淡で示す図である。FIG. 4 is a diagram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of HCl (concentration 5 mM) for 2 hours in the immersion step S4. 図５は、浸漬工程Ｓ４においてＨＣｌの水溶液（濃度５ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布を３次元的に示す図である。FIG. 5 is a diagram three-dimensionally showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of HCl (concentration 5 mM) for 2 hours in the immersion step S4. 図６は、浸漬工程Ｓ４においてＨＮＯ３の水溶液（濃度５ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布を濃淡で示す図である。FIG. 6 is a diagram showing the height distribution of the metal film after immersing the surface-enhanced substrate in an aqueous solution of HNO 3 (concentration 5 mM) for 2 hours in the immersion step S4. 図７は、浸漬工程Ｓ４においてＨＮＯ３の水溶液（濃度５ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布を３次元的に示す図である。FIG. 7 is a diagram three-dimensionally showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous HNO 3 solution (concentration 5 mM) for 2 hours in the immersion step S4. 図８は、浸漬工程Ｓ４においてＨ２ＳＯ４の水溶液（濃度５ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布を濃淡で示す図である。FIG. 8 is a diagram showing the height distribution of the metal film after immersing the surface-enhanced substrate in an aqueous solution of H 2 SO 4 (concentration 5 mM) for 2 hours in the immersion step S4. 図９は、浸漬工程Ｓ４においてＨ２ＳＯ４の水溶液（濃度５ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布を３次元的に示す図である。FIG. 9 is a diagram three-dimensionally showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of H 2 SO 4 (concentration 5 mM) for 2 hours in the immersion step S4. 図１０は、浸漬工程Ｓ４においてＨＣｌ、ＨＮＯ３およびＨ２ＳＯ４それぞれの水溶液（濃度５ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布をヒストグラムで示す図である。FIG. 10 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate was immersed in aqueous solutions of HCl, HNO 3 and H 2 SO 4 (concentration 5 mM) for 2 hours in the immersion step S4. be. 図１１は、浸漬工程Ｓ４においてＨＣｌ、ＨＮＯ３およびＨ２ＳＯ４それぞれの水溶液（濃度５ｍＭ）に２時間に亘って浸漬した表面増強基板を用いて被検体としてのｐ-メルカプト安息香酸（ｐ-ＭＢＡ）のラマンシフトを測定した結果を示すグラフである。FIG . 11 shows p- mercaptobenzoic acid ( p- MBA) is a graph showing the results of measuring the Raman shift. 図１２は、浸漬工程Ｓ４においてＨＣｌの水溶液（濃度０.０１ｍＭ～５ｍＭ）に２時間に亘って浸漬した表面増強基板を用いて被検体としてのｐ-ＭＢＡのラマンシフトを測定した結果を示すグラフである。FIG. 12 is a graph showing the results of measuring the Raman shift of p-MBA as a test sample using the surface-enhanced substrate immersed in an aqueous solution of HCl (concentration 0.01 mM to 5 mM) for 2 hours in the immersion step S4. is. 図１３は、浸漬工程Ｓ４においてＨ２ＳＯ４の水溶液（濃度１ｍＭまたは５ｍＭ）に２時間に亘って浸漬した表面増強基板を用いて被検体としての4,4'-ビピリジル（４ＢＰ）のラマンシフトを測定した結果を示すグラフである。FIG. 13 shows the Raman shift of 4,4′-bipyridyl (4BP) as an analyte using a surface-enhanced substrate immersed in an aqueous solution of H 2 SO 4 (concentration 1 mM or 5 mM) for 2 hours in the immersion step S4. is a graph showing the results of measuring 図１４は、浸漬工程Ｓ４においてＮａＣｌの水溶液（濃度５ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布を濃淡で示す図である。FIG. 14 is a diagram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of NaCl (concentration: 5 mM) for 2 hours in the immersion step S4. 図１５は、浸漬工程Ｓ４においてＮａＣｌの水溶液（濃度５ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布を３次元的に示す図である。FIG. 15 is a diagram three-dimensionally showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of NaCl (concentration: 5 mM) for 2 hours in the immersion step S4. 図１６は、浸漬工程Ｓ４においてＮａＢｒの水溶液（濃度５ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布を濃淡で示す図である。FIG. 16 is a diagram showing the height distribution of the metal film after immersing the surface-enhanced substrate in an aqueous NaBr solution (concentration: 5 mM) for 2 hours in the immersion step S4. 図１７は、浸漬工程Ｓ４においてＮａＢｒの水溶液（濃度５ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布を３次元的に示す図である。FIG. 17 is a diagram three-dimensionally showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of NaBr (concentration: 5 mM) for 2 hours in the immersion step S4. 図１８は、浸漬工程Ｓ４においてＮａＩの水溶液（濃度５ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布を濃淡で示す図である。FIG. 18 is a diagram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous NaI solution (concentration: 5 mM) for 2 hours in the immersion step S4. 図１９は、浸漬工程Ｓ４においてＮａＩの水溶液（濃度５ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布を３次元的に示す図である。FIG. 19 is a diagram three-dimensionally showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous NaI solution (concentration: 5 mM) for 2 hours in the immersion step S4. 図２０は、浸漬工程Ｓ４においてＮａＣｌ、ＮａＢｒおよびＮａＩそれぞれの水溶液（濃度５ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布をヒストグラムで示す図である。FIG. 20 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in aqueous solutions of NaCl, NaBr and NaI (concentration 5 mM) for 2 hours in the immersion step S4. 図２１は、浸漬工程Ｓ４においてＨＣｌの水溶液（濃度５ｍＭ）に２分間または２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布をヒストグラムで示す図である。FIG. 21 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of HCl (concentration 5 mM) for 2 minutes or 2 hours in the immersion step S4. 図２２は、浸漬工程Ｓ４においてＮａＣｌの水溶液（濃度５ｍＭ）に２分間または２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布をヒストグラムで示す図である。FIG. 22 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of NaCl (concentration: 5 mM) for 2 minutes or 2 hours in the immersion step S4. 図２３は、浸漬工程Ｓ４においてＮａＣｌの水溶液（濃度０.０１ｍＭ、１ｍＭ、１００ｍＭの各値）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布をヒストグラムで示す図である。FIG. 23 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate was immersed in an aqueous solution of NaCl (concentrations of 0.01 mM, 1 mM, and 100 mM) for 2 hours in the immersion step S4. be. 図２４は、浸漬工程Ｓ４においてＮａＣｌの水溶液（濃度１０００ｍＭ又は５０００ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布をヒストグラムで示す図である。FIG. 24 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of NaCl (concentration 1000 mM or 5000 mM) for 2 hours in the immersion step S4. 図２５は、浸漬工程Ｓ４においてＮａＢｒの水溶液（濃度１ｍＭ、１０ｍＭ又は１００ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布をヒストグラムで示す図である。FIG. 25 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous NaBr solution (concentration of 1 mM, 10 mM, or 100 mM) for 2 hours in the immersion step S4. 図２６は、浸漬工程Ｓ４においてＮａＩの水溶液（濃度１ｍＭ又は１０ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布をヒストグラムで示す図である。FIG. 26 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous NaI solution (concentration of 1 mM or 10 mM) for 2 hours in the immersion step S4. 図２７は、浸漬工程Ｓ４においてＮａＩの水溶液（濃度０.０１ｍＭ）に２分間、５分間または１２０分間に亘って表面増強基板を浸漬した後の金属膜の高さ分布をヒストグラムで示す図である。FIG. 27 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate was immersed in an aqueous solution of NaI (concentration 0.01 mM) for 2 minutes, 5 minutes, or 120 minutes in the immersion step S4. . 図２８は、図２７の一部を拡大して示す図である。28 is an enlarged view of a part of FIG. 27. FIG. 図２９は、浸漬工程Ｓ４においてＨＣｌの水溶液（濃度２０ｍＭ）に２時間に亘って浸漬した表面増強基板を用いて被検体としてのｐ-ＭＢＡのラマンシフトを測定した結果を示すグラフである。FIG. 29 is a graph showing the results of measuring the Raman shift of p-MBA as a specimen using the surface-enhanced substrate immersed in an aqueous solution of HCl (concentration 20 mM) for 2 hours in the immersion step S4. 図３０は、浸漬工程Ｓ４においてＨ２ＳＯ４の水溶液（濃度１０００ｍＭ）に２時間に亘って浸漬した表面増強基板を用いて被検体としてのｐ-ＭＢＡのラマンシフトを測定した結果を示すグラフである。FIG. 30 is a graph showing the results of measuring the Raman shift of p-MBA as a specimen using the surface-enhanced substrate immersed in an aqueous solution of H 2 SO 4 (concentration 1000 mM) for 2 hours in the immersion step S4. be. 図３１は、浸漬工程Ｓ４においてＨＮＯ３の水溶液（濃度１００ｍＭ）に２時間に亘って浸漬した表面増強基板を用いて被検体としてのｐ-ＭＢＡのラマンシフトを測定した結果を示すグラフである。FIG. 31 is a graph showing the results of measuring the Raman shift of p-MBA as a specimen using a surface-enhanced substrate immersed in an aqueous solution of HNO 3 (concentration 100 mM) for 2 hours in the immersion step S4. 図３２は、浸漬工程Ｓ４においてＮａＣｌの水溶液（濃度２０００ｍＭ）に２時間に亘って浸漬した表面増強基板を用いて被検体としてのｐ-ＭＢＡのラマンシフトを測定した結果を示すグラフである。FIG. 32 is a graph showing the results of measuring the Raman shift of p-MBA as a specimen using a surface-enhanced substrate immersed in an aqueous NaCl solution (concentration: 2000 mM) for 2 hours in the immersion step S4. 図３３は、浸漬工程Ｓ４においてＮａＢｒの水溶液（濃度１ｍＭ）に２時間に亘って浸漬した表面増強基板を用いて被検体としてのｐ-ＭＢＡのラマンシフトを測定した結果を示すグラフである。FIG. 33 is a graph showing the results of measuring the Raman shift of p-MBA as a specimen using a surface-enhanced substrate immersed in an aqueous solution of NaBr (concentration 1 mM) for 2 hours in the immersion step S4. 図３４は、浸漬工程Ｓ４においてＨＣｌの水溶液（濃度２０ｍＭ）に２時間に亘って浸漬した表面増強基板を用いて被検体としての４ＢＰのラマンシフトを測定した結果を示すグラフである。FIG. 34 is a graph showing the results of measuring the Raman shift of 4BP as a specimen using the surface-enhanced substrate immersed in an aqueous solution of HCl (concentration 20 mM) for 2 hours in the immersion step S4. 図３５は、浸漬工程Ｓ４においてＨ２ＳＯ４の水溶液（濃度１０００ｍＭ）に２時間に亘って浸漬した表面増強基板を用いて被検体としての４ＢＰのラマンシフトを測定した結果を示すグラフである。FIG. 35 is a graph showing the results of measuring the Raman shift of 4BP as a specimen using the surface-enhanced substrate immersed in an aqueous solution of H 2 SO 4 (concentration 1000 mM) for 2 hours in the immersion step S4. 図３６は、浸漬工程Ｓ４においてＨＮＯ３の水溶液（濃度１００ｍＭ）に２時間に亘って浸漬した表面増強基板を用いて被検体としての４ＢＰのラマンシフトを測定した結果を示すグラフである。FIG. 36 is a graph showing the results of measuring the Raman shift of 4BP as an analyte using the surface-enhanced substrate immersed in an aqueous HNO 3 solution (concentration 100 mM) for 2 hours in the immersion step S4. 図３７は、浸漬工程Ｓ４においてＮａＣｌの水溶液（濃度２０００ｍＭ）に２時間に亘って浸漬した表面増強基板を用いて被検体としての４ＢＰのラマンシフトを測定した結果を示すグラフである。FIG. 37 is a graph showing the results of measuring the Raman shift of 4BP as a specimen using the surface-enhanced substrate immersed in an aqueous NaCl solution (concentration: 2000 mM) for 2 hours in the immersion step S4. 図３８は、浸漬工程Ｓ４においてＮａＢｒの水溶液（濃度１ｍＭ）に２時間に亘って浸漬した表面増強基板を用いて被検体としての４ＢＰのラマンシフトを測定した結果を示すグラフである。FIG. 38 is a graph showing the results of measuring the Raman shift of 4BP as a specimen using the surface-enhanced substrate immersed in an aqueous solution of NaBr (concentration 1 mM) for 2 hours in the immersion step S4. 図３９は、浸漬工程Ｓ４においてＮａＩの水溶液（濃度０.０１ｍＭ）に２分間に亘って浸漬した表面増強基板を用いて被検体としての４ＢＰのラマンシフトを測定した結果を示すグラフである。FIG. 39 is a graph showing the results of measuring the Raman shift of 4BP as a specimen using the surface-enhanced substrate immersed in an aqueous solution of NaI (concentration 0.01 mM) for 2 minutes in the immersion step S4.
　以下、添付図面を参照して、表面増強基板作製方法及び表面増強分光方法の実施の形態を詳細に説明する。なお、図面の説明において同一の要素には同一の符号を付し、重複する説明を省略する。本発明は、これらの例示に限定されるものではない。 Hereinafter, embodiments of the surface-enhanced substrate manufacturing method and the surface-enhanced spectroscopy method will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and overlapping descriptions are omitted. The present invention is not limited to these exemplifications.
　図１は、表面増強基板作製方法を説明するフローチャートである。表面増強基板作製方法は、支持体準備工程Ｓ１、下地層形成工程Ｓ２、金属膜形成工程Ｓ３、浸漬工程Ｓ４、洗浄工程Ｓ５および乾燥工程Ｓ６を順に行うことにより、ナノメートルオーダーのサイズの微小構造を表面に有する金属膜が支持体の表面に形成された表面増強基板を作製する。 FIG. 1 is a flow chart explaining the surface-enhanced substrate manufacturing method. In the surface-enhanced substrate preparation method, a support preparing step S1, a base layer forming step S2, a metal film forming step S3, an immersion step S4, a washing step S5, and a drying step S6 are sequentially performed to form a nanometer-order microstructure. is formed on the surface of a support to prepare a surface-enhanced substrate.
　支持体準備工程Ｓ１では、後の金属膜形成工程Ｓ３で表面に金属膜が形成されるべき支持体を準備する。支持体の材料は、金属または半導体など任意であるが、後の浸漬工程Ｓ４の際に溶解し難いものが好ましい。支持体の形状も、任意であるが、後の下地層形成工程Ｓ２および金属膜形成工程Ｓ３の容易さを考慮すると平板状であるのが好ましい。また、支持体（特に、後の金属膜形成工程Ｓ３で金属膜が形成されるべき表面）を洗浄するのが好ましい。 In the support preparation step S1, a support on which a metal film is to be formed on the surface in the metal film formation step S3 is prepared. The material of the support is arbitrary, such as a metal or a semiconductor, but a material that is difficult to dissolve in the subsequent immersion step S4 is preferable. The shape of the support is also arbitrary, but a flat plate shape is preferred in consideration of the ease of the subsequent base layer forming step S2 and metal film forming step S3. Also, it is preferable to wash the support (in particular, the surface on which the metal film is to be formed in the subsequent metal film forming step S3).
　支持体の表面は、平滑であってもよいが、ナノメートルオーダーのサイズの微小構造を有するのが好ましい。支持体は、所定の材料を所定形状に切り出しただけのものであってもよいが、その後に表面に微小構造を形成したものであってもよい。 The surface of the support may be smooth, but preferably has a nanometer-order microstructure. The support may be obtained by simply cutting out a predetermined material into a predetermined shape, or may be obtained by forming a microstructure on the surface after that.
　支持体の表面に形成される微小構造としては、例えばＺｎＯナノロッドまたはベーマイト（boehmite）等による微小構造が挙げられる。ＺｎＯナノロッドは、柱状に成長した酸化亜鉛（ＺｎＯ）の結晶である。ベーマイトは、結晶構造を有するアルミニウム水和酸化皮膜である。また、支持体の表面に微小構造を形成する他の方法が特許文献２，３に記載されている。 The microstructures formed on the surface of the support include, for example, microstructures made of ZnO nanorods or boehmite. ZnO nanorods are crystals of zinc oxide (ZnO) grown in a columnar shape. Boehmite is an aluminum hydrated oxide film with a crystalline structure. Other methods for forming microstructures on the surface of a support are described in Patent Documents 2 and 3.
　下地層形成工程Ｓ２では、支持体の表面に下地層を形成する。下地層は、支持体の表面に対する金属膜（後の金属膜形成工程Ｓ３で支持体表面に形成されるべき金属膜）の付着力を高めるものである。下地層の材料は、任意でよいが、好適にはチタン（Ｔｉ）、クロム（Ｃｒ）またはニッケル（Ｎｉ）等の金属を含む。下地層は例えば蒸着により形成される。下地層の厚さは例えば数ｎｍ～数十ｎｍであってよい。下地層は島状構造の薄膜であってもよい。 In the base layer forming step S2, a base layer is formed on the surface of the support. The underlayer enhances the adhesion of the metal film (the metal film to be formed on the surface of the support in the subsequent metal film forming step S3) to the surface of the support. The material of the underlayer may be arbitrary, but preferably includes a metal such as titanium (Ti), chromium (Cr) or nickel (Ni). The underlying layer is formed by vapor deposition, for example. The thickness of the underlayer may be, for example, several nanometers to several tens of nanometers. The underlayer may be a thin film having an island structure.
　金属膜形成工程Ｓ３では、支持体の表面に金属膜を形成する。金属膜の材料は、銀（Ａｇ）、金（Ａｕ）、銅（Ｃｕ）または白金（Ｐｔ）等の電場増強効果を奏し得る金属を含むが、好適にはＡｇまたはＡｕを含む。金属膜は例えば蒸着により形成される。なお、蒸着以外の気相成長法（たとえばスパッタ）により金属膜を形成してもよい。金属膜の厚さは、任意であり、数ｎｍ～数百ｎｍであってもよい。 In the metal film forming step S3, a metal film is formed on the surface of the support. Materials for the metal film include metals capable of enhancing an electric field, such as silver (Ag), gold (Au), copper (Cu) or platinum (Pt), and preferably include Ag or Au. A metal film is formed by vapor deposition, for example. Note that the metal film may be formed by a vapor deposition method (for example, sputtering) other than vapor deposition. The thickness of the metal film is arbitrary, and may be several nanometers to several hundreds of nanometers.
　金属膜の表面（支持体側の面に対し反対側の面）は、支持体表面や下地層が微小構造を有していない場合であっても、一般に、蒸着等による形成の直後においてナノメートルオーダーのサイズの微小構造を有している。支持体表面または下地層が微小構造を有している場合には、金属膜の表面は、支持体表面または下地層の微小構造に応じた微小構造を有することができる。 The surface of the metal film (the surface opposite to the support side) generally has a nanometer order immediately after formation by vapor deposition or the like, even if the support surface or the underlying layer does not have a microstructure. It has a microstructure with a size of When the support surface or the underlying layer has a microstructure, the surface of the metal film can have a microstructure corresponding to the microstructure of the support surface or the underlying layer.
　浸漬工程Ｓ４では、金属膜形成工程Ｓ３において金属膜が形成された支持体を電解質水溶液に浸漬することで、金属膜の表面の微小構造が改質された表面増強基板を作製する。ここで用いられる電解質水溶液は、酸またはハロゲンイオンを含む水溶液である。 In the immersion step S4, the support on which the metal film was formed in the metal film formation step S3 is immersed in an aqueous electrolyte solution to fabricate a surface-enhanced substrate in which the microstructure of the surface of the metal film is modified. The aqueous electrolyte solution used here is an aqueous solution containing acid or halogen ions.
　酸を含む水溶液として、塩酸（ＨＣｌ）、硫酸（Ｈ２ＳＯ４）または硝酸（ＨＮＯ３）等を含む水溶液が用いられる。ハロゲンイオンを含む水溶液として、塩素イオン（Ｃｌ－）、臭素イオン（Ｂｒ－）またはヨウ素イオン（Ｉ－）等を含む水溶液が用いられる。金属膜表面の微小構造の改質は、金属膜表面の微小構造の高さ（支持体表面を基準とする高さ）の分布の変更、または、金属膜表面の微小構造のピーク高さ位置の間隔の変更、等を含む。 As the aqueous solution containing acid, an aqueous solution containing hydrochloric acid (HCl), sulfuric acid (H 2 SO 4 ), nitric acid (HNO 3 ), or the like is used. As the aqueous solution containing halogen ions, an aqueous solution containing chlorine ions (Cl − ), bromide ions (Br − ), iodine ions (I − ), or the like is used. Modification of the microstructure on the surface of the metal film involves changing the distribution of the height of the microstructure on the surface of the metal film (height relative to the surface of the support), or changing the peak height position of the microstructure on the surface of the metal film. Including changing intervals, etc.
　なお、浸漬工程Ｓ４の際に加熱の必要はなく、浸漬工程Ｓ４を室温で行うことができる。浸漬工程Ｓ４の際に電圧印加の必要もない。また、浸漬工程Ｓ４の際に金属イオンを供給する必要もない。 Note that there is no need for heating during the immersion step S4, and the immersion step S4 can be performed at room temperature. No voltage application is required during the immersion step S4. Moreover, it is not necessary to supply metal ions during the immersion step S4.
　洗浄工程Ｓ５では、浸漬工程Ｓ４において作製された表面増強基板を清浄な液体で洗浄することで、浸漬工程Ｓ４で用いた電解質水溶液を洗い流す。ここで洗浄に用いられる液体は、金属膜を溶解させないもののうちから選ばれ、好適には純水やエタノール等である。 In the cleaning step S5, the surface-enhanced substrate produced in the immersion step S4 is washed with a clean liquid to wash away the electrolyte aqueous solution used in the immersion step S4. The liquid used for cleaning is selected from liquids that do not dissolve the metal film, and is preferably pure water, ethanol, or the like.
　乾燥工程Ｓ６では、洗浄工程Ｓ５において洗浄された表面増強基板を乾燥させる。このとき、表面増強基板に清浄な気体（例えば窒素ガスや希ガス）を吹き付けることで、表面増強基板を乾燥させてもよい。 In the drying step S6, the surface-enhanced substrate cleaned in the cleaning step S5 is dried. At this time, the surface-enhanced substrate may be dried by blowing clean gas (for example, nitrogen gas or rare gas) onto the surface-enhanced substrate.
　各工程の処理の一例は次のとおりである。後に説明する試作例の表面増強基板は、次に説明する各工程の処理により作製されたものである。 An example of the processing of each process is as follows. A surface-enhanced substrate of a prototype example to be described later was manufactured by the treatment of each step described below.
　支持体準備工程Ｓ１において、シリコン（Ｓｉ）からなる支持体を準備する場合、ペルオキソ二硫酸ナトリウム水溶液（濃度０.０１５ｇ／ｍＬ）で２０分間に亘って支持体を煮沸洗浄し、その後に支持体を純水でリンスして乾燥させる。 In the support preparation step S1, when preparing a support made of silicon (Si), the support is boiled and washed with an aqueous solution of sodium peroxodisulfate (concentration: 0.015 g/mL) for 20 minutes. rinse with pure water and dry.
　支持体準備工程Ｓ１において、Ｓｉからなる支持体の表面にＺｎＯナノロッドによる微小構造を形成する場合、支持体表面に下地層を形成した後、シード層としてＡｇまたはＡｕを成膜する。そして、硝酸亜鉛六水和物水溶液と水酸化ナトリウム水溶液とを混合し、この混合液に支持体を浸漬して加熱した後、混合液から取り出した支持体を純水でリンスして窒素ガスブローで乾燥させる。 In the support preparation step S1, when forming a microstructure of ZnO nanorods on the surface of a support made of Si, a base layer is formed on the support surface, and then Ag or Au is deposited as a seed layer. Then, an aqueous solution of zinc nitrate hexahydrate and an aqueous solution of sodium hydroxide are mixed, and the support is immersed in this mixed solution and heated. dry.
　支持体準備工程Ｓ１において、Ｓｉからなる支持体の表面にベーマイトによる微小構造を形成する場合、アルミニウム（Ａｌ）を支持体表面に真空蒸着してＡｌ層を形成し、この支持体を沸騰した純水に浸漬した後、取り出した支持体を純水でリンスして窒素ガスブローで乾燥させる。 In the support preparation step S1, when forming a microstructure of boehmite on the surface of a support made of Si, aluminum (Al) is vacuum-deposited on the surface of the support to form an Al layer, and the support is boiled pure. After being immersed in water, the support taken out is rinsed with pure water and dried by blowing nitrogen gas.
　下地層形成工程Ｓ２において、Ｓｉからなる平板状の支持体の表面に、Ｔｉからなる下地層を形成する場合、真空蒸着法（抵抗ボード加熱式）が用いられる。このとき、真空度は１～２×１０－５Ｔｏｒｒとされ、蒸着レートは０.０１ｎｍ／ｓｅｃ程度とされる。 In the underlayer forming step S2, a vacuum vapor deposition method (resistance board heating method) is used to form a Ti underlayer on the surface of a flat support made of Si. At this time, the degree of vacuum is set to 1 to 2×10 −5 Torr, and the deposition rate is set to about 0.01 nm/sec.
　金属膜形成工程Ｓ３において、Ｓｉからなる平板状の支持体の表面に、ＡｇまたはＡｕからなる金属膜を形成する場合、真空蒸着法（抵抗ボード加熱式）が用いられる。このとき、真空度は１～２×１０－５Ｔｏｒｒとされ、蒸着レートは０.０２ｎｍ／ｓｅｃ程度とされる。 In the metal film formation step S3, when forming a metal film made of Ag or Au on the surface of a plate-shaped support made of Si, a vacuum vapor deposition method (resistance board heating method) is used. At this time, the degree of vacuum is set to 1 to 2×10 −5 Torr, and the deposition rate is set to about 0.02 nm/sec.
　なお、下地層形成工程Ｓ２は行われなくてもよい。また、ＡｇまたはＡｕを含む金属膜が支持体の表面に形成され該金属膜の表面に微小構造を有する表面増強基板が既に存在する場合には、その表面増強基板に対して浸漬工程Ｓ４以降の処理を行うことにより、金属膜の表面の微小構造が改質された表面増強基板を作製することができる。 Note that the base layer forming step S2 may not be performed. Further, when a metal film containing Ag or Au is formed on the surface of a support and a surface-enhanced substrate having a microstructure on the surface of the metal film already exists, the surface-enhanced substrate is subjected to the immersion step S4 and subsequent steps. By performing the treatment, it is possible to produce a surface-enhanced substrate in which the microstructure of the surface of the metal film is modified.
　以上のようにして作製された表面増強基板は、ＳＥＲＳ分光、ＳＥＩＲＡ分光およびＳＰＦ分光等の表面増強分光方法において用いられる。これらの表面増強分光方法では、表面増強基板の金属膜表面の金属微小構造に光を照射することで、増強された電場（光子場）を発生させる。そして、その金属微小構造の近傍に存在する被検体と光との相互作用（ラマン散乱、吸収、蛍光、等）を検出することにより、被検体を高感度に分析することができる。 The surface-enhanced substrate produced as described above is used in surface-enhanced spectroscopy methods such as SERS spectroscopy, SEIRA spectroscopy, and SPF spectroscopy. In these surface-enhanced spectroscopy methods, an enhanced electric field (photon field) is generated by irradiating the metal microstructure on the surface of the metal film of the surface-enhanced substrate with light. By detecting the interaction (Raman scattering, absorption, fluorescence, etc.) between the subject and light present in the vicinity of the metal microstructure, the subject can be analyzed with high sensitivity.
　以上のようにして作製された表面増強基板を用いることにより、より高感度な分析が可能となる。また、この表面増強基板作製方法によれば、表面増強基板を容易に作製することができる。 By using the surface-enhanced substrate produced as described above, more sensitive analysis becomes possible. Further, according to this method for producing a surface-enhanced substrate, a surface-enhanced substrate can be produced easily.
　次に、金属膜形成工程Ｓ３でＡｇ膜を形成し浸漬工程Ｓ４で各種の酸を用いて改質した表面増強基板の試作例について説明する。ここでは、表面増強基板は、Ｓｉからなる支持体の表面に、Ｔｉからなる厚さ３ｎｍ程度の下地層を形成し、更にＡｇからなる厚さ１０ｎｍ程度の金属膜を形成したものであった。 Next, an example of a trial production of a surface-enhanced substrate in which an Ag film is formed in the metal film forming step S3 and modified using various acids in the immersion step S4 will be described. Here, the surface-enhanced substrate was obtained by forming an underlying layer of Ti with a thickness of about 3 nm on the surface of a support made of Si, and further forming a metal film of Ag with a thickness of about 10 nm.
　図２および図３は、金属膜形成工程Ｓ３後（浸漬工程Ｓ４前）の表面増強基板の金属膜の高さ分布を示す図である。図２は、支持体表面に平行であって互いに直交する２方向をｘ軸およびｙ軸として、ｘｙ面における各位置の金属膜の高さ（厚さ）を濃淡で示している。図３は、金属膜の厚さ（高さ）方向をｚ軸として、ｘｙ面における各位置の金属膜の高さ（厚さ）を３次元的に示している。 2 and 3 are diagrams showing the height distribution of the metal film of the surface-enhanced substrate after the metal film formation step S3 (before the immersion step S4). FIG. 2 shows the height (thickness) of the metal film at each position in the xy plane with the two directions parallel to the support surface and perpendicular to each other as the x axis and the y axis. FIG. 3 three-dimensionally shows the height (thickness) of the metal film at each position on the xy plane, with the thickness (height) direction of the metal film as the z-axis.
　これらは、原子間力顕微鏡（Atomic　Force　Microscope：ＡＦＭ）を用いた観察により取得されたものである（以降の金属膜の高さ分布を示す各図も同様。）。これらの図に示されるとおり、金属膜形成工程Ｓ３後（浸漬工程Ｓ４前）の表面増強基板の金属膜の表面は微小構造を有している。 These were obtained by observation using an atomic force microscope (AFM) (the same applies to each figure showing the height distribution of the metal film below). As shown in these figures, the surface of the metal film of the surface-enhanced substrate after the metal film formation step S3 (before the immersion step S4) has a microstructure.
　図４および図５は、浸漬工程Ｓ４においてＨＣｌの水溶液（濃度５ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布を示す図である。図４は、ｘｙ面における各位置の金属膜の高さ（厚さ）を濃淡で示している。図５は、ｘｙ面における各位置の金属膜の高さ（厚さ）を３次元的に示している。 FIGS. 4 and 5 are diagrams showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of HCl (concentration 5 mM) for 2 hours in the immersion step S4. FIG. 4 shows the height (thickness) of the metal film at each position on the xy plane in shading. FIG. 5 three-dimensionally shows the height (thickness) of the metal film at each position on the xy plane.
　図６および図７は、浸漬工程Ｓ４においてＨＮＯ３の水溶液（濃度５ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布を示す図である。図６は、ｘｙ面における各位置の金属膜の高さ（厚さ）を濃淡で示している。図７は、ｘｙ面における各位置の金属膜の高さ（厚さ）を３次元的に示している。 6 and 7 are diagrams showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of HNO 3 (concentration 5 mM) for 2 hours in the immersion step S4. FIG. 6 shows the height (thickness) of the metal film at each position on the xy plane with shading. FIG. 7 three-dimensionally shows the height (thickness) of the metal film at each position on the xy plane.
　図８および図９は、浸漬工程Ｓ４においてＨ２ＳＯ４の水溶液（濃度５ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布を示す図である。図８は、ｘｙ面における各位置の金属膜の高さ（厚さ）を濃淡で示している。図９は、ｘｙ面における各位置の金属膜の高さ（厚さ）を３次元的に示している。 8 and 9 are diagrams showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of H 2 SO 4 (concentration 5 mM) for 2 hours in the immersion step S4. FIG. 8 shows the height (thickness) of the metal film at each position on the xy plane in shading. FIG. 9 three-dimensionally shows the height (thickness) of the metal film at each position on the xy plane.
　図４～図９に示されるとおり、浸漬工程Ｓ４前（図２、図３）と比べて浸漬工程Ｓ４後では、金属膜の表面の微小構造は改質されていた。また、金属膜の表面の微小構造の改質の程度は、用いた酸の種類によって異なっていた。 As shown in FIGS. 4 to 9, the microstructure of the surface of the metal film was modified after the immersion step S4 compared to before the immersion step S4 (FIGS. 2 and 3). Moreover, the degree of modification of the microstructure on the surface of the metal film varied depending on the type of acid used.
　図１０は、浸漬工程Ｓ４においてＨＣｌ、ＨＮＯ３およびＨ２ＳＯ４それぞれの水溶液（濃度５ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布をヒストグラムで示す図である。この図は、金属膜形成工程Ｓ３後（浸漬工程Ｓ４前）の金属膜の高さ分布をも示している。 FIG. 10 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate was immersed in aqueous solutions of HCl, HNO 3 and H 2 SO 4 (concentration 5 mM) for 2 hours in the immersion step S4. be. This figure also shows the height distribution of the metal film after the metal film forming step S3 (before the immersion step S4).
　この図に示されるように、何れの場合も、浸漬工程Ｓ４前と比べて浸漬工程Ｓ４後では、表面増強基板の金属膜の表面の微小構造は改質され、高さヒストグラムが右方向（高さ増加方向）にシフトしている。その効果は、ＨＣｌを用いた場合に最も高く、続いて、Ｈ２ＳＯ４を用いた場合に高かった。 As shown in this figure, in any case, the microstructure of the surface of the metal film of the surface-enhanced substrate is modified after the immersion step S4 compared to before the immersion step S4, and the height histogram is shifted to the right (higher). increasing). The effect was highest with HCl followed by H 2 SO 4 .
　次に、金属膜形成工程Ｓ３でＡｇ膜を形成し浸漬工程Ｓ４で各種の酸を用いて改質した表面増強基板を用いて行ったＳＥＲＳ分光の実験例について説明する。ここでは、表面増強基板は、Ｓｉからなる支持体の表面に、ＺｎＯナノロッドによる微小構造を形成し、更にＡｇからなる厚さ５０ｎｍ程度の金属膜を形成したものであった。ＳＥＲＳ分光において、用いたレーザ光の波長は７８５ｎｍであり、レーザ光強度は３.４ｍＷであり、１秒間に亘るラマンスペクトル測定を１００回行って平均値をとった。 Next, an example of a SERS spectroscopy experiment performed using a surface-enhanced substrate on which an Ag film is formed in the metal film formation step S3 and modified with various acids in the immersion step S4 will be described. Here, the surface-enhanced substrate was obtained by forming a microstructure of ZnO nanorods on the surface of a support made of Si, and further forming a metal film made of Ag with a thickness of about 50 nm. In the SERS spectroscopy, the wavelength of the laser light used was 785 nm, the laser light intensity was 3.4 mW, and Raman spectrum measurement was performed 100 times over 1 second and the average value was taken.
　図１１は、浸漬工程Ｓ４においてＨＣｌ、ＨＮＯ３およびＨ２ＳＯ４それぞれの水溶液（濃度５ｍＭ）に２時間に亘って浸漬した表面増強基板を用いて被検体としてのｐ-メルカプト安息香酸（4-mercaptobenzoic　acid：ｐ-ＭＢＡ）のラマンシフトを測定した結果を示すグラフである。この図は、金属膜形成工程Ｓ３後（浸漬工程Ｓ４前）の表面増強基板を用いた場合の結果をも示している。 FIG . 11 shows p- mercaptobenzoic acid ( 4- It is a graph which shows the result of having measured the Raman shift of mercaptobenzoic acid (p-MBA). This figure also shows the results when using the surface-enhanced substrate after the metal film formation step S3 (before the immersion step S4).
　この実験例では、洗浄工程Ｓ５において表面増強基板を純水で洗浄し、乾燥工程Ｓ６において表面増強基板を窒素ガスブローで乾燥させた。この表面増強基板をｐ-ＭＢＡエタノール溶液（濃度１ｍＭ）に２時間に亘って浸漬した後、取り出した表面増強基板をエタノールでリンスして窒素ガスブローで乾燥させた。 In this experimental example, the surface-enhanced substrate was washed with pure water in the cleaning step S5, and dried by blowing nitrogen gas in the drying step S6. After this surface-enhanced substrate was immersed in a p-MBA ethanol solution (concentration: 1 mM) for 2 hours, the surface-enhanced substrate was taken out, rinsed with ethanol, and dried by blowing nitrogen gas.
　この図に示されるように、浸漬工程Ｓ４前の表面増強基板を用いた場合と比べて、浸漬工程Ｓ４後の表面増強基板を用いた場合では、ラマン散乱強度が大きい。その効果は、ＨＣｌを用いた場合に最も高く、続いて、Ｈ２ＳＯ４を用いた場合に高かった。 As shown in this figure, the Raman scattering intensity is higher in the case of using the surface-enhanced substrate after the immersion step S4 than in the case of using the surface-enhanced substrate before the immersion step S4. The effect was highest with HCl followed by H 2 SO 4 .
　図１２は、浸漬工程Ｓ４においてＨＣｌの水溶液（濃度０.０１ｍＭ～５ｍＭ）に２時間に亘って浸漬した表面増強基板を用いて被検体としてのｐ-ＭＢＡのラマンシフトを測定した結果を示すグラフである。この図は、金属膜形成工程Ｓ３後（浸漬工程Ｓ４前）の表面増強基板を用いた場合の結果をも示している。 FIG. 12 is a graph showing the results of measuring the Raman shift of p-MBA as a test sample using the surface-enhanced substrate immersed in an aqueous solution of HCl (concentration 0.01 mM to 5 mM) for 2 hours in the immersion step S4. is. This figure also shows the results when using the surface-enhanced substrate after the metal film formation step S3 (before the immersion step S4).
　この実験例では、浸漬工程Ｓ４におけるＨＣｌ濃度を０.０１ｍＭ～５ｍＭの範囲の各値とし、洗浄工程Ｓ５において表面増強基板を純水で洗浄し、乾燥工程Ｓ６において表面増強基板を窒素ガスブローで乾燥させた。この表面増強基板をｐ-ＭＢＡエタノール溶液（濃度１ｍＭ）に２時間に亘って浸漬した後、取り出した表面増強基板をエタノールでリンスして窒素ガスブローで乾燥させた。 In this experimental example, the HCl concentration in the immersion step S4 is set to each value in the range of 0.01 mM to 5 mM, the surface-enhanced substrate is washed with pure water in the cleaning step S5, and the surface-enhanced substrate is dried by blowing nitrogen gas in the drying step S6. let me After this surface-enhanced substrate was immersed in a p-MBA ethanol solution (concentration: 1 mM) for 2 hours, the surface-enhanced substrate was taken out, rinsed with ethanol, and dried by blowing nitrogen gas.
　この図に示されるように、浸漬工程Ｓ４におけるＨＣｌ濃度が高いほど、ラマン散乱強度が大きかった。 As shown in this figure, the higher the HCl concentration in the immersion step S4, the higher the Raman scattering intensity.
　図１３は、浸漬工程Ｓ４においてＨ２ＳＯ４の水溶液（濃度１ｍＭまたは５ｍＭ）に２時間に亘って浸漬した表面増強基板を用いて被検体としての4,4'-ビピリジル（4,4’-bipyridyl：４ＢＰ）のラマンシフトを測定した結果を示すグラフである。この図は、金属膜形成工程Ｓ３後（浸漬工程Ｓ４前）の表面増強基板を用いた場合の結果をも示している。 FIG . 13 shows 4,4′-bipyridyl (4,4′- It is a graph which shows the result of having measured the Raman shift of bipyridyl:4BP). This figure also shows the results when using the surface-enhanced substrate after the metal film formation step S3 (before the immersion step S4).
　この実験例では、浸漬工程Ｓ４におけるＨ２ＳＯ４濃度を１ｍＭまたは５ｍＭとし、洗浄工程Ｓ５において表面増強基板を純水で洗浄し、乾燥工程Ｓ６において表面増強基板を窒素ガスブローで乾燥させた。この表面増強基板を４ＢＰ水溶液（濃度１０μＭ）に３０分間に亘って浸漬した後、取り出した表面増強基板を純水でリンスして窒素ガスブローで乾燥させた。 In this experimental example, the H 2 SO 4 concentration in the immersion step S4 was set to 1 mM or 5 mM, the surface-enhanced substrate was washed with pure water in the washing step S5, and dried by blowing nitrogen gas in the drying step S6. After this surface-enhanced substrate was immersed in a 4BP aqueous solution (concentration: 10 μM) for 30 minutes, the surface-enhanced substrate was taken out, rinsed with pure water, and dried by blowing nitrogen gas.
　この図に示されるように、浸漬工程Ｓ４におけるＨ２ＳＯ４濃度が高いほど、ラマン散乱強度が大きかった。 As shown in this figure, the higher the H 2 SO 4 concentration in the immersion step S4, the higher the Raman scattering intensity.
　図１１～図１３に示されるとおり、浸漬工程Ｓ４において酸を含む水溶液に浸漬した表面増強基板を用いることにより、被検体をより高感度に分析することができた。 As shown in FIGS. 11 to 13, by using the surface-enhanced substrate immersed in an acid-containing aqueous solution in the immersion step S4, the specimen could be analyzed with higher sensitivity.
　次に、金属膜形成工程Ｓ３でＡｇ膜を形成し浸漬工程Ｓ４で各種のハロゲンイオンを含む水溶液を用いて改質した表面増強基板の試作例について説明する。ここでは、表面増強基板は、Ｓｉからなる支持体の表面に、Ｔｉからなる厚さ３ｎｍ程度の下地層を形成し、更にＡｇからなる厚さ１０ｎｍ程度の金属膜を形成したものであった。 Next, a description will be given of a prototype example of a surface-enhanced substrate in which an Ag film is formed in the metal film forming step S3 and modified using an aqueous solution containing various halogen ions in the immersion step S4. Here, the surface-enhanced substrate was obtained by forming an underlying layer of Ti with a thickness of about 3 nm on the surface of a support made of Si, and further forming a metal film of Ag with a thickness of about 10 nm.
　図１４および図１５は、浸漬工程Ｓ４においてＮａＣｌの水溶液（濃度５ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布を示す図である。図１４は、ｘｙ面における各位置の金属膜の高さ（厚さ）を濃淡で示している。図１５は、ｘｙ面における各位置の金属膜の高さ（厚さ）を３次元的に示している。 14 and 15 are diagrams showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of NaCl (concentration 5 mM) for 2 hours in the immersion step S4. FIG. 14 shows the height (thickness) of the metal film at each position on the xy plane in shading. FIG. 15 three-dimensionally shows the height (thickness) of the metal film at each position on the xy plane.
　図１６および図１７は、浸漬工程Ｓ４においてＮａＢｒの水溶液（濃度５ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布を示す図である。図１６は、ｘｙ面における各位置の金属膜の高さ（厚さ）を濃淡で示している。図１７は、ｘｙ面における各位置の金属膜の高さ（厚さ）を３次元的に示している。 16 and 17 are diagrams showing the height distribution of the metal film after the surface-enhanced substrate was immersed in an aqueous solution of NaBr (concentration 5 mM) for 2 hours in the immersion step S4. FIG. 16 shows the height (thickness) of the metal film at each position on the xy plane with shading. FIG. 17 three-dimensionally shows the height (thickness) of the metal film at each position on the xy plane.
　図１８および図１９は、浸漬工程Ｓ４においてＮａＩの水溶液（濃度５ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布を示す図である。図１８は、ｘｙ面における各位置の金属膜の高さ（厚さ）を濃淡で示している。図１９は、ｘｙ面における各位置の金属膜の高さ（厚さ）を３次元的に示している。 18 and 19 are diagrams showing the height distribution of the metal film after the surface-enhanced substrate was immersed in an aqueous NaI solution (concentration 5 mM) for 2 hours in the immersion step S4. FIG. 18 shows the height (thickness) of the metal film at each position on the xy plane with shading. FIG. 19 three-dimensionally shows the height (thickness) of the metal film at each position on the xy plane.
　図１４～図１９に示されるとおり、浸漬工程Ｓ４前（図２、図３）と比べて浸漬工程Ｓ４後では、金属膜の表面の微小構造は改質されていた。また、金属膜の表面の微小構造の改質の程度は、用いたハロゲンイオンの種類によって異なっていた。 As shown in FIGS. 14 to 19, the microstructure of the surface of the metal film was modified after the immersion step S4 compared to before the immersion step S4 (FIGS. 2 and 3). Also, the degree of modification of the microstructure on the surface of the metal film varied depending on the type of halogen ion used.
　図２０は、浸漬工程Ｓ４においてＮａＣｌ、ＮａＢｒおよびＮａＩそれぞれの水溶液（濃度５ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布をヒストグラムで示す図である。この図は、金属膜形成工程Ｓ３後（浸漬工程Ｓ４前）の金属膜の高さ分布をも示している。 FIG. 20 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate was immersed in aqueous solutions (concentration 5 mM) of NaCl, NaBr, and NaI for 2 hours in the immersion step S4. This figure also shows the height distribution of the metal film after the metal film forming step S3 (before the immersion step S4).
　この図に示されるように、何れの場合も、浸漬工程Ｓ４前と比べて浸漬工程Ｓ４後では、表面増強基板の金属膜の表面の微小構造は改質され、高さヒストグラムが右方向（高さ増加方向）にシフトしている。その効果は、ＮａＣｌを用いた場合に最も高く、続いて、ＮａＢｒを用いた場合に高かった。 As shown in this figure, in any case, the microstructure of the surface of the metal film of the surface-enhanced substrate is modified after the immersion step S4 compared to before the immersion step S4, and the height histogram is shifted to the right (higher). increasing). The effect was highest with NaCl, followed by NaBr.
　図２１は、浸漬工程Ｓ４においてＨＣｌの水溶液（濃度５ｍＭ）に２分間または２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布をヒストグラムで示す図である。図２２は、浸漬工程Ｓ４においてＮａＣｌの水溶液（濃度５ｍＭ）に２分間または２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布をヒストグラムで示す図である。これらの図は、金属膜形成工程Ｓ３後（浸漬工程Ｓ４前）の金属膜の高さ分布をも示している。 FIG. 21 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of HCl (concentration 5 mM) for 2 minutes or 2 hours in the immersion step S4. FIG. 22 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of NaCl (concentration: 5 mM) for 2 minutes or 2 hours in the immersion step S4. These figures also show the height distribution of the metal film after the metal film formation step S3 (before the immersion step S4).
　これらの図を比較して分かるように、浸漬工程Ｓ４においてＨＣｌの水溶液およびＮａＣｌの水溶液の何れを用いた場合にも２分間に亘って表面増強基板を浸漬することにより金属膜の表面の微小構造を改質することができた。その改質の効果は、ＨＣｌの水溶液を用いる場合の方が大きかった。 As can be seen by comparing these figures, the microstructure of the surface of the metal film was obtained by immersing the surface-enhanced substrate for 2 minutes in both the HCl aqueous solution and the NaCl aqueous solution in the immersion step S4. could be modified. The effect of the modification was greater when using an aqueous solution of HCl.
　図２３は、浸漬工程Ｓ４においてＮａＣｌの水溶液（濃度０.０１ｍＭ、１ｍＭ、１００ｍＭの各値）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布をヒストグラムで示す図である。この図に示されるように、ハロゲンイオンの濃度が高いほど、高さヒストグラムが右方向（高さ増加方向）に大きくシフトした。 FIG. 23 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate was immersed in an aqueous solution of NaCl (concentrations of 0.01 mM, 1 mM, and 100 mM) for 2 hours in the immersion step S4. be. As shown in this figure, the higher the concentration of halogen ions, the more the height histogram shifted to the right (in the direction of increasing height).
　Ｘ線光電子分光法（X-ray　Photoelectron　Spectroscopy：ＸＰＳ）により、浸漬工程Ｓ４後の金属膜の表面近傍の元素分布を測定したところ、浸漬工程Ｓ４においてＮａＣｌ水溶液（濃度５ｍＭ）を用いた場合では、Ａｇ元素に対するＣｌ元素の割合は１３％程度以下であった。浸漬工程Ｓ４においてＨＣｌ水溶液（濃度５ｍＭ）を用いた場合では、Ａｇ元素に対するＣｌ元素の割合は１０％程度以下であった。 When the element distribution near the surface of the metal film after the immersion step S4 was measured by X-ray Photoelectron Spectroscopy (XPS), when an aqueous NaCl solution (concentration 5 mM) was used in the immersion step S4, The ratio of Cl element to Ag element was about 13% or less. When the HCl aqueous solution (concentration 5 mM) was used in the immersion step S4, the ratio of Cl element to Ag element was about 10% or less.
　浸漬工程Ｓ４においてＨ２ＳＯ４水溶液（濃度５ｍＭ）を用いた場合では、Ａｇ元素に対するＳＯ４の割合は数％程度以下であった。また、浸漬工程Ｓ４においてＨＮＯ３水溶液（濃度５ｍＭ）を用いた場合では、ＮＯ３は検出されなかった。これらのことから、浸漬工程Ｓ４における金属膜表面の微小構造に関する改質は、Ａｇ化合物の生成によるものではなく、Ａｇの成長によるものであることが分かる。 When the H 2 SO 4 aqueous solution (concentration 5 mM) was used in the immersion step S4, the ratio of SO 4 to Ag element was about several percent or less. Further, NO 3 was not detected when the HNO 3 aqueous solution (concentration 5 mM) was used in the immersion step S4. From these facts, it can be seen that the modification of the microstructure of the metal film surface in the immersion step S4 is not due to the formation of Ag compounds, but due to the growth of Ag.
　次に、金属膜形成工程Ｓ３でＡｕ膜を形成し浸漬工程Ｓ４で各種の酸および各種のハロゲンイオンを用いて改質した表面増強基板の試作例について説明する。ここでは、表面増強基板は、Ｓｉからなる支持体の表面に、Ｔｉからなる厚さ３ｎｍ程度の下地層を形成し、更にＡｕからなる厚さ５ｎｍ程度の金属膜を形成したものであった。浸漬工程Ｓ４で用いた水溶液は、ＨＣｌ、ＨＮＯ３、Ｈ２ＳＯ４、ＮａＣｌ、ＮａＢｒおよびＮａＩそれぞれの水溶液であった。また、浸漬工程Ｓ４で用いた水溶液の濃度を様々な値とし、浸漬時間も様々な値とした。 Next, a description will be given of prototype examples of surface-enhanced substrates in which an Au film is formed in the metal film forming step S3 and modified using various acids and various halogen ions in the immersion step S4. Here, the surface-enhanced substrate was obtained by forming an underlying layer of Ti with a thickness of about 3 nm on the surface of a support made of Si, and further forming a metal film of Au with a thickness of about 5 nm. The aqueous solutions used in the immersion step S4 were aqueous solutions of HCl, HNO 3 , H 2 SO 4 , NaCl, NaBr and NaI. Also, the concentration of the aqueous solution used in the immersion step S4 was varied, and the immersion time was also varied.
　図２４は、浸漬工程Ｓ４においてＮａＣｌの水溶液（濃度１０００ｍＭ又は５０００ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布をヒストグラムで示す図である。図２５は、浸漬工程Ｓ４においてＮａＢｒの水溶液（濃度１ｍＭ、１０ｍＭ又は１００ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布をヒストグラムで示す図である。図２６は、浸漬工程Ｓ４においてＮａＩの水溶液（濃度１ｍＭ又は１０ｍＭ）に２時間に亘って表面増強基板を浸漬した後の金属膜の高さ分布をヒストグラムで示す図である。 FIG. 24 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous solution of NaCl (concentration 1000 mM or 5000 mM) for 2 hours in the immersion step S4. FIG. 25 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous NaBr solution (concentration of 1 mM, 10 mM, or 100 mM) for 2 hours in the immersion step S4. FIG. 26 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate is immersed in an aqueous NaI solution (concentration of 1 mM or 10 mM) for 2 hours in the immersion step S4.
　図２７は、浸漬工程Ｓ４においてＮａＩの水溶液（濃度０.０１ｍＭ）に２分間、５分間または１２０分間に亘って表面増強基板を浸漬した後の金属膜の高さ分布をヒストグラムで示す図である。図２８は、図２７の一部を拡大して示す図である。これらの図は、金属膜形成工程Ｓ３後（浸漬工程Ｓ４前）の金属膜の高さ分布をも示している。 FIG. 27 is a histogram showing the height distribution of the metal film after the surface-enhanced substrate was immersed in an aqueous solution of NaI (concentration 0.01 mM) for 2 minutes, 5 minutes, or 120 minutes in the immersion step S4. . 28 is an enlarged view of a part of FIG. 27. FIG. These figures also show the height distribution of the metal film after the metal film formation step S3 (before the immersion step S4).
　これらの図に示されるように、浸漬工程Ｓ４でＮａＣｌ、ＮａＢｒおよびＮａＩそれぞれの水溶液の何れを用いた場合にも、Ａｕからなる金属膜の高さヒストグラムは右方向（高さ増加方向）にシフトした。また、ハロゲンイオンの濃度が高いほど、高さヒストグラムが右方向（高さ増加方向）に大きくシフトした。 As shown in these figures, the height histogram of the metal film made of Au shifts to the right (in the direction of height increase) regardless of the use of each of the aqueous solutions of NaCl, NaBr, and NaI in the immersion step S4. bottom. Also, the higher the concentration of halogen ions, the greater the shift of the height histogram to the right (in the direction of increasing height).
　次に、金属膜形成工程Ｓ３でＡｕ膜を形成し浸漬工程Ｓ４で各種の酸および各種のハロゲンイオンを用いて改質した表面増強基板を用いて行ったＳＥＲＳ分光の実験例について説明する。ここでは、表面増強基板は、Ｓｉからなる支持体の表面に、ベーマイトによる厚さ５００ｎｍ程度の微小構造を形成し、更にＡｕからなる厚さ２０ｎｍ程度の金属膜を形成したものであった。 Next, an example of an SERS spectroscopy experiment performed using a surface-enhanced substrate modified with various acids and various halogen ions in the immersion step S4 after forming an Au film in the metal film forming step S3 will be described. Here, the surface-enhanced substrate was obtained by forming a fine structure of boehmite with a thickness of about 500 nm on the surface of a support made of Si, and further forming a metal film of Au with a thickness of about 20 nm.
　ＳＥＲＳ分光において、用いたレーザ光の波長は７８５ｎｍであり、レーザ光強度は３.４ｍＷであり、１秒間に亘るラマンスペクトル測定を１００回行って平均値をとった。被検体としてｐ-ＭＢＡおよび４ＢＰを用いた。 In the SERS spectroscopy, the wavelength of the laser light used was 785 nm, the laser light intensity was 3.4 mW, and the average value was obtained by performing 100 Raman spectrum measurements over 1 second. p-MBA and 4BP were used as test subjects.
　図２９は、浸漬工程Ｓ４においてＨＣｌの水溶液（濃度２０ｍＭ）に２時間に亘って浸漬した表面増強基板を用いて被検体としてのｐ-ＭＢＡのラマンシフトを測定した結果を示すグラフである。図３０は、浸漬工程Ｓ４においてＨ２ＳＯ４の水溶液（濃度１０００ｍＭ）に２時間に亘って浸漬した表面増強基板を用いて被検体としてのｐ-ＭＢＡのラマンシフトを測定した結果を示すグラフである。図３１は、浸漬工程Ｓ４においてＨＮＯ３の水溶液（濃度１００ｍＭ）に２時間に亘って浸漬した表面増強基板を用いて被検体としてのｐ-ＭＢＡのラマンシフトを測定した結果を示すグラフである。 FIG. 29 is a graph showing the results of measuring the Raman shift of p-MBA as a specimen using the surface-enhanced substrate immersed in an aqueous solution of HCl (concentration 20 mM) for 2 hours in the immersion step S4. FIG. 30 is a graph showing the results of measuring the Raman shift of p-MBA as a specimen using the surface-enhanced substrate immersed in an aqueous solution of H 2 SO 4 (concentration 1000 mM) for 2 hours in the immersion step S4. be. FIG. 31 is a graph showing the results of measuring the Raman shift of p-MBA as a specimen using a surface-enhanced substrate immersed in an aqueous solution of HNO 3 (concentration 100 mM) for 2 hours in the immersion step S4.
　図３２は、浸漬工程Ｓ４においてＮａＣｌの水溶液（濃度２０００ｍＭ）に２時間に亘って浸漬した表面増強基板を用いて被検体としてのｐ-ＭＢＡのラマンシフトを測定した結果を示すグラフである。図３３は、浸漬工程Ｓ４においてＮａＢｒの水溶液（濃度１ｍＭ）に２時間に亘って浸漬した表面増強基板を用いて被検体としてのｐ-ＭＢＡのラマンシフトを測定した結果を示すグラフである。これらの図は、金属膜形成工程Ｓ３後（浸漬工程Ｓ４前）の表面増強基板を用いた場合の結果をも示している。 FIG. 32 is a graph showing the results of measuring the Raman shift of p-MBA as a specimen using a surface-enhanced substrate immersed in an aqueous NaCl solution (concentration: 2000 mM) for 2 hours in the immersion step S4. FIG. 33 is a graph showing the results of measuring the Raman shift of p-MBA as a specimen using a surface-enhanced substrate immersed in an aqueous solution of NaBr (concentration 1 mM) for 2 hours in the immersion step S4. These figures also show the results when using the surface-enhanced substrate after the metal film formation step S3 (before the immersion step S4).
　これらの図に示されるように、浸漬工程Ｓ４において酸またはハロゲンイオンを含む水溶液に浸漬した表面増強基板を用いることにより、被検体としてのｐ-ＭＢＡをより高感度に分析することができた。 As shown in these figures, by using the surface-enhanced substrate immersed in an aqueous solution containing an acid or halogen ions in the immersion step S4, p-MBA as an analyte could be analyzed with higher sensitivity.
　図３４は、浸漬工程Ｓ４においてＨＣｌの水溶液（濃度２０ｍＭ）に２時間に亘って浸漬した表面増強基板を用いて被検体としての４ＢＰのラマンシフトを測定した結果を示すグラフである。図３５は、浸漬工程Ｓ４においてＨ２ＳＯ４の水溶液（濃度１０００ｍＭ）に２時間に亘って浸漬した表面増強基板を用いて被検体としての４ＢＰのラマンシフトを測定した結果を示すグラフである。図３６は、浸漬工程Ｓ４においてＨＮＯ３の水溶液（濃度１００ｍＭ）に２時間に亘って浸漬した表面増強基板を用いて被検体としての４ＢＰのラマンシフトを測定した結果を示すグラフである。 FIG. 34 is a graph showing the results of measuring the Raman shift of 4BP as a specimen using the surface-enhanced substrate immersed in an aqueous solution of HCl (concentration 20 mM) for 2 hours in the immersion step S4. FIG. 35 is a graph showing the results of measuring the Raman shift of 4BP as a specimen using the surface-enhanced substrate immersed in an aqueous solution of H 2 SO 4 (concentration 1000 mM) for 2 hours in the immersion step S4. FIG. 36 is a graph showing the results of measuring the Raman shift of 4BP as an analyte using the surface-enhanced substrate immersed in an aqueous HNO 3 solution (concentration 100 mM) for 2 hours in the immersion step S4.
　図３７は、浸漬工程Ｓ４においてＮａＣｌの水溶液（濃度２０００ｍＭ）に２時間に亘って浸漬した表面増強基板を用いて被検体としての４ＢＰのラマンシフトを測定した結果を示すグラフである。図３８は、浸漬工程Ｓ４においてＮａＢｒの水溶液（濃度１ｍＭ）に２時間に亘って浸漬した表面増強基板を用いて被検体としての４ＢＰのラマンシフトを測定した結果を示すグラフである。図３９は、浸漬工程Ｓ４においてＮａＩの水溶液（濃度０.０１ｍＭ）に２分間に亘って浸漬した表面増強基板を用いて被検体としての４ＢＰのラマンシフトを測定した結果を示すグラフである。これらの図は、金属膜形成工程Ｓ３後（浸漬工程Ｓ４前）の表面増強基板を用いた場合の結果をも示している。 FIG. 37 is a graph showing the results of measuring the Raman shift of 4BP as an analyte using the surface-enhanced substrate immersed in an aqueous NaCl solution (concentration: 2000 mM) for 2 hours in the immersion step S4. FIG. 38 is a graph showing the results of measuring the Raman shift of 4BP as a specimen using the surface-enhanced substrate immersed in an aqueous solution of NaBr (concentration 1 mM) for 2 hours in the immersion step S4. FIG. 39 is a graph showing the results of measuring the Raman shift of 4BP as a specimen using the surface-enhanced substrate immersed in an aqueous solution of NaI (concentration 0.01 mM) for 2 minutes in the immersion step S4. These figures also show the results when using the surface-enhanced substrate after the metal film formation step S3 (before the immersion step S4).
　これらの図に示されるように、浸漬工程Ｓ４において酸またはハロゲンイオンを含む水溶液に浸漬した表面増強基板を用いることにより、被検体としての４ＢＰをより高感度に分析することができた。 As shown in these figures, by using the surface-enhanced substrate immersed in an aqueous solution containing an acid or halogen ions in the immersion step S4, 4BP as an analyte could be analyzed with higher sensitivity.
　ＸＰＳにより、浸漬工程Ｓ４後の金属膜の表面近傍の元素分布を測定したところ、浸漬工程Ｓ４においてＮａＣｌ水溶液（濃度２０００ｍＭ）を用いた場合では、Ｃｌ元素は検出されなかった。浸漬工程Ｓ４においてＮａＢｒ水溶液（濃度１０ｍＭ）を用いた場合では、Ａｕ元素に対するＢｒ元素の割合は数％程度であった。また、浸漬工程Ｓ４においてＮａＩ水溶液（濃度１ｍＭ）を用いた場合では、Ａｕ元素に対するＩ元素の割合は１０％程度以下であった。これらのことから、浸漬工程Ｓ４における金属膜表面の微小構造に関する改質は、Ａｕ化合物の生成によるものではなく、Ａｕの成長によるものであることが分かる。 When the element distribution near the surface of the metal film after the immersion step S4 was measured by XPS, no Cl element was detected when the NaCl aqueous solution (concentration: 2000 mM) was used in the immersion step S4. When the NaBr aqueous solution (concentration: 10 mM) was used in the immersion step S4, the ratio of the Br element to the Au element was about several percent. Moreover, when the NaI aqueous solution (concentration 1 mM) was used in the immersion step S4, the ratio of the I element to the Au element was about 10% or less. From these facts, it can be seen that the modification of the microstructure of the metal film surface in the immersion step S4 is not due to the formation of Au compounds, but due to the growth of Au.
　以上では、試作した表面増強基板を用いて行ったＳＥＲＳ分光の実験例について説明したが、表面増強基板は、他の表面増強分光方法（例えばＳＥＩＲＡ分光およびＳＰＦ分光等）にも用いられ得る。これらの表面増強分光方法では、表面増強基板の金属膜表面の金属微小構造に光を照射することで、増強された電場（光子場）を発生させる。そして、その金属微小構造の近傍に存在する被検体と光との相互作用（ラマン散乱、吸収、蛍光、等）を検出することにより、被検体を高感度に分析することができる。 In the above, an experimental example of SERS spectroscopy performed using the surface-enhanced substrate produced as a prototype has been described, but the surface-enhanced substrate can also be used for other surface-enhanced spectroscopy methods (eg, SEIRA spectroscopy, SPF spectroscopy, etc.). In these surface-enhanced spectroscopy methods, an enhanced electric field (photon field) is generated by irradiating the metal microstructure on the surface of the metal film of the surface-enhanced substrate with light. By detecting the interaction (Raman scattering, absorption, fluorescence, etc.) between the subject and light present in the vicinity of the metal microstructure, the subject can be analyzed with high sensitivity.
　以上のようにして作製されて金属膜表面の微小構造が改質された表面増強基板を用いることにより、より高感度な分析が可能となる。また、この表面増強基板作製方法によれば、電圧印加や金属イオン供給の必要がなく室温で金属表面を改質した表面増強基板を容易に作製することができる。 By using the surface-enhanced substrate produced as described above and having a modified microstructure on the surface of the metal film, more sensitive analysis becomes possible. Moreover, according to this method for producing a surface-enhanced substrate, it is possible to easily produce a surface-enhanced substrate having a modified metal surface at room temperature without applying voltage or supplying metal ions.
　表面増強基板作製方法、及び表面増強分光方法は、上記実施形態及び構成例に限定されるものではなく、種々の変形が可能である。 The surface-enhanced substrate manufacturing method and the surface-enhanced spectroscopy method are not limited to the above-described embodiments and configuration examples, and various modifications are possible.
　上記実施形態による表面増強基板作製方法は、（１）銀または金を含む金属膜を支持体の表面に形成する金属膜形成工程と、（２）金属膜形成工程において金属膜が形成された支持体を、酸またはハロゲンイオンを含む電解質水溶液に浸漬することで、金属膜の表面の微小構造が改質された表面増強基板を作製する浸漬工程と、を備える。 The method for producing a surface-enhanced substrate according to the above embodiment includes (1) a metal film forming step of forming a metal film containing silver or gold on the surface of a support; an immersion step of immersing the body in an aqueous electrolyte solution containing acid or halogen ions to fabricate a surface-enhanced substrate having a modified microstructure on the surface of the metal film.
　上記の表面増強基板作製方法は、金属膜が形成されるべき表面に微小構造を有する支持体を準備する支持体準備工程を更に備える構成としてもよい。 The above surface-enhanced substrate manufacturing method may further include a support preparation step of preparing a support having a microstructure on the surface on which the metal film is to be formed.
　上記の表面増強基板作製方法は、金属膜形成工程の前に、支持体の表面に対する金属膜の付着力を高める下地層を支持体の表面に形成する下地層形成工程を更に備える構成としてもよい。 The method for producing a surface-enhanced substrate may further include, prior to the metal film forming step, an underlayer forming step of forming on the surface of the support an underlayer that enhances the adhesion of the metal film to the surface of the support. .
　上記実施形態による表面増強基板作製方法は、銀または金を含む金属膜が支持体の表面に形成され該金属膜の表面に微小構造を有する表面増強基板を、酸またはハロゲンイオンを含む電解質水溶液に浸漬することで、金属膜の表面の微小構造が改質された表面増強基板を作製する。 The method for producing a surface-enhanced substrate according to the above-described embodiment includes placing a surface-enhanced substrate having a metal film containing silver or gold on the surface of a support and having microstructures on the surface of the metal film in an aqueous electrolyte solution containing acid or halogen ions. The immersion produces a surface-enhanced substrate in which the microstructure of the surface of the metal film is modified.
　上記実施形態による表面増強分光方法は、上記構成の表面増強基板作製方法により作製された表面増強基板を用いて被検体の分析を行う。 The surface-enhanced spectroscopy method according to the above embodiment analyzes a subject using the surface-enhanced substrate produced by the surface-enhanced substrate production method having the above configuration.
　本発明は、より高感度な分析が可能な表面増強基板を容易に作製することができる方法、及び表面増強基板を用いて被検体を高感度に分析することができる表面増強分光方法として利用可能である。 INDUSTRIAL APPLICABILITY The present invention can be used as a method for easily producing a surface-enhanced substrate that enables more sensitive analysis, and as a surface-enhanced spectroscopic method for highly sensitive analysis of a subject using the surface-enhanced substrate. is.
　Ｓ１…支持体準備工程、Ｓ２…下地層形成工程、Ｓ３…金属膜形成工程、Ｓ４…浸漬工程、Ｓ５…洗浄工程、Ｓ６…乾燥工程。 S1... Support preparation step, S2... Base layer forming step, S3... Metal film forming step, S4... Immersion step, S5... Washing step, S6... Drying step.

Claims (5)

  1. 　銀または金を含む金属膜を支持体の表面に形成する金属膜形成工程と、
    　前記金属膜形成工程において前記金属膜が形成された前記支持体を、酸またはハロゲンイオンを含む電解質水溶液に浸漬することで、前記金属膜の表面の微小構造が改質された表面増強基板を作製する浸漬工程と、
    を備える、表面増強基板作製方法。     a metal film forming step of forming a metal film containing silver or gold on the surface of the support;
    By immersing the support on which the metal film is formed in the metal film forming step in an electrolyte aqueous solution containing acid or halogen ions, a surface-enhanced substrate having a modified microstructure on the surface of the metal film is produced. a dipping step to
    A method for fabricating a surface-enhanced substrate, comprising:
  2. 　前記金属膜が形成されるべき表面に微小構造を有する前記支持体を準備する支持体準備工程を更に備える、請求項１に記載の表面増強基板作製方法。 The surface-enhanced substrate fabrication method according to claim 1, further comprising a support preparation step of preparing the support having a microstructure on the surface on which the metal film is to be formed.
  3. 　前記金属膜形成工程の前に、前記支持体の表面に対する前記金属膜の付着力を高める下地層を前記支持体の表面に形成する下地層形成工程を更に備える、請求項１または２に記載の表面増強基板作製方法。 3. The method according to claim 1, further comprising, prior to the metal film forming step, forming a base layer on the surface of the support to increase adhesion of the metal film to the surface of the support. A surface-enhanced substrate fabrication method.
  4. 　銀または金を含む金属膜が支持体の表面に形成され該金属膜の表面に微小構造を有する表面増強基板を、酸またはハロゲンイオンを含む電解質水溶液に浸漬することで、前記金属膜の表面の微小構造が改質された表面増強基板を作製する、表面増強基板作製方法。 A surface-enhanced substrate having a metal film containing silver or gold formed on the surface of a support and having a microstructure on the surface of the metal film is immersed in an electrolyte aqueous solution containing acid or halogen ions, thereby removing the surface of the metal film. A surface-enhanced substrate fabrication method for fabricating a surface-enhanced substrate having a modified microstructure.
  5. 　請求項１～４の何れか１項に記載の表面増強基板作製方法により作製された表面増強基板を用いて被検体の分析を行う、表面増強分光方法。 A surface-enhanced spectroscopic method for analyzing a subject using a surface-enhanced substrate produced by the method for producing a surface-enhanced substrate according to any one of claims 1 to 4.
PCT/JP2022/041744 2021-12-03 2022-11-09 Method for producing surface enhanced substrate and surface enhanced spectroscopy WO2023100610A1 (en)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5693152A (en) * 1995-08-14 1997-12-02 University Of Wyoming Molecular specific detector for separation science using surface enhanced raman spectroscopy
WO2014156088A1 (en) * 2013-03-27 2014-10-02 富士フイルム株式会社 Photo-electric-field enhancement device and manufacturing method therefor

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5693152A (en) * 1995-08-14 1997-12-02 University Of Wyoming Molecular specific detector for separation science using surface enhanced raman spectroscopy
WO2014156088A1 (en) * 2013-03-27 2014-10-02 富士フイルム株式会社 Photo-electric-field enhancement device and manufacturing method therefor

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