JP6252053B2 - Surface-enhanced Raman scattering measurement substrate and manufacturing method thereof - Google Patents

Description

  The present invention relates to a surface-enhanced Raman scattering measurement substrate and a manufacturing method thereof.

In recent years, in the field of biotechnology centered on life science, there is a demand for ultra-sensitive analysis technology that allows cells to be observed without labeling.
As a detection method in the field of biotechnology, surface enhanced Raman spectroscopy (hereinafter, sometimes abbreviated as SERS) is attracting attention as an ultrasensitive analysis method used for identification of substances. Raman spectroscopy is monochromatic light because the difference in energy between the light scattered by the Raman effect and the incident light corresponds to the vibrational level, rotational level, or electron level energy of the molecules and crystals in the material. In this method, a laser is used as incident light, a chemical species is identified from the spectrum, and the target substance is quantified from the intensity of the scattered light, utilizing a phenomenon that is modulated into light reflecting the energy state unique to the molecule. Since the sensitivity of Raman spectroscopy is essentially low, there is a problem that it is not suitable for analyzing a small amount of sample. On the other hand, in metal nanoparticles, plasmons, which are a phenomenon in which free electrons existing on the metal surface oscillate collectively, exist on the metal surface, and this surface plasmon is coupled with a photoelectric field in the visible to near infrared region. , Significantly enhance the electric field at the surface of the metal nanoparticles. Using this surface plasmon resonance, when the molecules adsorbed on the surface of the metal nanoparticles are irradiated with laser light, the Raman scattered light generated from the adsorbed molecules can be dramatically enhanced. Has been attracting attention.

As a method for obtaining a Raman scattering measurement substrate, for example, in Patent Document 1, an ampholyte having at least an amino group and a carbonyl group is dispersed in a colloidal solution containing nanoparticles having a particle size of 100 nm or less of a metal having SERS activity. A colloidal solution containing the ampholyte is dropped onto a metal substrate, and agglomeration is initiated by the electrode potential difference between the metal substrate and the nanoparticles to form a hot site (a place where an electric field enhancement effect due to surface plasmon resonance occurs remarkably). A method is disclosed.
In Patent Document 2, as a method for producing a polymer film containing metal fine particles, an aqueous dispersion of metal fine particles and an organic solvent solution in which a polymer is dissolved are mixed and separated into an aqueous phase and an organic phase. The metal fine particle aggregate formed at the liquid-liquid interface is formed by forming a film of the polymer contained in the organic phase after the metal fine particles are agglomerated at the liquid-liquid interface in the separation solution and then forming the film. And a method for producing a polymer film in which the metal fine particle thin film aggregate is contained in one surface layer portion of the film is disclosed.

  However, in the Raman scattering measurement substrate obtained by the method using the dispersion liquid as described in Patent Documents 1 and 2, the metal fine particles provided in the Raman scattering measurement substrate are covered with a dispersant such as a surfactant. Therefore, the enhancement effect of Raman scattering by the metal fine particles may be insufficient. In addition, in the method of forming an aggregate of metal nanoparticles using such a dispersion, it is substantially difficult to precisely control the degree and shape of aggregation.

On the other hand, as a method different from the method of arranging the metal fine particles from the dispersion, a method of forming noble metal nanowires synthesized by a vapor phase method on a substrate and forming hot sites by contact or intersection between the noble metal nanowires (Patent Document) 3) or a method in which a noble metal nanowire synthesized by a vapor phase method and a noble metal nanoparticle self-assembled on the surface of the noble metal nanowire are arranged on a substrate and hot sites are formed by bonding the surface of the noble metal nanowire and the noble metal nanoparticle ( Patent document 4) is also known.
However, there is a problem that precise polarization control is required because the enhancement effect by hot sites formed by the intersection of noble metal nanowires and the combination of noble metal nanoparticles has strong polarization dependence (Non-Patent Document 1, 2).

International Publication No. 2010/101209 Pamphlet JP 2011-16953 A JP 2010-532472 A JP 2011-81001 A Fumiyoshi Nagasawa et al., “Observation of polarization anisotropy of surface-enhanced Raman scattering photons in metal nanogap”, 5th Molecular Science Conference (2011), 1D14 Erik C. Garnett et al., "Self-limited plasmonic welding of silver nanowire junctions", Nature Materials, Vol.11 (2012), pp.241-249

  The present invention has been made in view of the above problems, and provides a surface-enhanced Raman scattering measurement substrate that has high measurement sensitivity and can be manufactured by a simple method, and a method for manufacturing the surface-enhanced Raman scattering measurement substrate. For the purpose.

SERS measurement substrate according to the present invention, a plurality of minute projections are closely spaced, average 1000nm der following distance between adjacent said microprojection is, perpendicular to the depth direction of the microprojections It has a structure in which the cross-sectional area occupancy of the material part forming the microprotrusions in the horizontal cross-section when it is assumed to be cut at a horizontal plane is continuously increased gradually from the top of the microprotrusions toward the deepest part. And the ratio of the average height of the microprotrusions to the average distance between the adjacent microprotrusions is 0.8 to 2.5. It has metal nanoparticles smaller than the average of the distance between the microprotrusions, and the metal nanoparticles are supported on the surface of the microprotrusion structure.

  In the surface-enhanced Raman scattering measurement substrate according to the present invention, it is preferable that the surface of the fine concavo-convex layer is composed of an inorganic oxide layer from the viewpoint of excellent measurement performance.

  In the surface-enhanced Raman scattering measurement substrate according to the present invention, the metal nanoparticles are one or more metal nano particles selected from the group consisting of gold, silver, copper, platinum, palladium, nickel, and alloys thereof. It is preferably a particle.

Method for producing a surface-enhanced Raman scattering measurement substrate according to the present invention, a plurality of minute projections are closely spaced, average 1000nm der following distance between adjacent said microprojection is, the depth of said microprojection The cross-sectional area occupancy rate of the material portion forming the microprojections in the horizontal cross section when assuming that it is cut at a horizontal plane orthogonal to the direction continuously increases gradually from the top of the microprojections toward the deepest portion. A step of preparing a fine concavo-convex layer having a microprojection structure having a structure and an average ratio of the height of the microprojections to an average distance between adjacent microprojections is 0.8 to 2.5 When,
And a step of forming and supporting metal nanoparticles by attaching metal atoms to the surface of the microprojection structure using a vapor deposition method.

  In the method for manufacturing a surface-enhanced Raman scattering measurement substrate according to the present invention, the vapor deposition method is adjusted so that the thickness of a vapor deposition film formed by metal atoms adhering to a flat surface is 40 nm or less. However, it is preferable because it is easy to form a hot site.

  In the method for producing a surface-enhanced Raman scattering measurement substrate according to the present invention, the metal nanoparticles are one or more selected from the group consisting of gold, silver, copper, platinum, palladium, nickel, and alloys thereof. It is preferable that it is a metal nanoparticle.

  According to the present invention, it is possible to provide a surface-enhanced Raman scattering measurement substrate that has high measurement sensitivity and can be manufactured by a simple method, and a method for manufacturing the surface-enhanced Raman scattering measurement substrate.

It is sectional drawing which shows typically an example of the board | substrate for surface enhancement Raman scattering measurement concerning this invention. It is sectional drawing which shows typically another example of the board | substrate for surface enhancement Raman scattering measurement concerning this invention. It is a figure which shows an example of a Delaunay diagram typically. It is the schematic which shows an example of the formation method of a fine uneven | corrugated layer. FIG. 5A is an example of a STEM image of the surface-enhanced Raman scattering measurement substrate according to the present invention, and FIG. 5B shows the STEM image of FIG. It is the image which extracted only the metal nanoparticle by binarizing. It is a measurement result of the Raman spectrum of rhodamine 6G in Example 1, Comparative Example 1 and Comparative Example 2. It is a measurement result of the Raman spectrum of rhodamine 6G in Example 2, Comparative Example 1, and Comparative Example 3.

In this specification, “film surface (plate surface, sheet surface)” means a film-like member (target) when the target film-like (plate-like, sheet-like) member is viewed as a whole and globally. It refers to a surface that coincides with the planar direction of a plate-like member or sheet-like member.
Further, the shape and geometric conditions used in this specification and the degree thereof are specified. For example, terms such as “parallel”, “orthogonal”, “identical”, length and distance values, etc. are strictly Without being bound by meaning, it should be interpreted including the extent to which similar functions can be expected.

  The surface-enhanced Raman scattering measurement substrate according to the present invention has a fine concavo-convex layer having a microprojection structure in which a plurality of microprojections are closely arranged and the average distance between adjacent microprojections is 1000 nm or less; Metal nanoparticles having an average particle diameter smaller than the average distance between the microprojections, and the metal nanoparticles are supported on the surface of the microprojection structure.

The method for manufacturing a surface-enhanced Raman scattering measurement substrate according to the present invention includes a micro unevenness having a microprojection structure in which a plurality of microprojections are closely arranged and an average distance between adjacent microprojections is 1000 nm or less. Preparing a layer;
And a step of forming and supporting metal nanoparticles by attaching metal atoms to the surface of the microprojection structure using a vapor deposition method.

The present inventors show SERS activity of silver particles and the like, and metal nanoparticles that normally do not exist stably as single particles are deposited on the surface of the predetermined microprojection structure by vapor deposition. It was found that the metal nanoparticles are formed by adhering, and that the metal nanoparticles are less likely to aggregate on the surface of the predetermined microprojection structure and can exist stably as single particles. Such an effect has been conventionally used as a method for producing metal nanoparticles, such as a method of reducing a metal in an aqueous solution, or a method that requires a long time for the reaction or a special environment. Therefore, it can be said that this is a remarkable effect that exceeds the range predicted from the technical level.
In addition, the surface-enhanced Raman scattering measurement substrate according to the present invention has a surface area of the surface of the specific microprojection structure larger than that of the flat surface, and thus can carry more metal nanoparticles than the flat surface. it can. As a result, the surface-enhanced Raman scattering measurement substrate according to the present invention can further increase the SERS activity by the metal nanoparticles, and is excellent in measurement sensitivity.
In addition, in the measurement substrate obtained by using the conventional dispersion liquid, there is a problem that the metal nanoparticles are covered with the dispersant and the SERS activity is deteriorated, and a firing step is necessary to remove the dispersant. There is a problem that the manufacturing process increases. In contrast, the surface-enhanced Raman scattering measurement substrate according to the present invention can be produced by a vapor phase method without using a dispersion. Therefore, the metal nanoparticles can be easily manufactured in one process, and the surface of the metal nanoparticles is not covered with a dispersant or the like, the SERS activity by the metal nanoparticles is high, and the measurement sensitivity is excellent.
Furthermore, in the surface-enhanced Raman scattering measurement substrate according to the present invention, since the metal nanoparticles are carried on the surface of the microprojection structure, the unevenness of the microprojection structure depends on the size and arrangement of the microprojections. By appropriately adjusting the surface shape, the metal nanoparticles can be arranged in a desired arrangement. For example, when metal nanoparticles are supported on the surface of a microprojection structure having a uniform concavo-convex surface shape with a small microprojection size and alignment deviation, the metal nanoparticles are easily arranged evenly. The hot sight is easily arranged evenly, and there is a merit that there is substantially no polarization dependence and precise polarization control becomes unnecessary.
Further, according to the method for manufacturing a surface-enhanced Raman scattering measurement substrate according to the present invention, metal nanoparticles are formed and supported by attaching metal atoms to the surface of the microprojection structure using a vapor deposition method. The size, shape, and arrangement of the metal nanoparticles can be appropriately adjusted to some extent by adjusting the shape of the surface of the microprojection structure. Therefore, it is possible to precisely control the conformation of the metal nanoparticles.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings attached to the present specification, for the sake of illustration and ease of understanding, the scale, the vertical / horizontal dimension ratio, and the like are appropriately changed and exaggerated from those of the actual product.
FIG. 1 is a cross-sectional view schematically showing an example of a surface-enhanced Raman scattering measurement substrate according to the present invention. The surface-enhanced Raman scattering measurement substrate 10 shown in FIG. It has the fine uneven | corrugated layer 20 which has the microprojection structure 21 arrange | positioned and the average of the distance d between the said adjacent microprotrusions 22 is 1000 nm or less, and an average particle diameter is from the average of the distance d between the said microprotrusions 22 Smaller metal nanoparticles 30 are supported on the surface of the microprojection structure 21. As shown in FIG. 1, the surface-enhanced Raman scattering measurement substrate 10 may include a transparent substrate 11 as a support.
FIG. 2 is a cross-sectional view schematically showing another example of the surface-enhanced Raman scattering measurement substrate according to the present invention. The surface-enhanced Raman scattering measurement substrate 10 ′ shown in FIG. The surface on the protruding structure 21 side is composed of the inorganic oxide layer 25 and does not include the transparent substrate 11.

<Fine uneven layer>
The surface-enhanced Raman scattering measurement substrate 10 according to the present invention includes a microprojection structure 21 in which a plurality of microprojections 22 are closely arranged and the average distance between adjacent microprojections 22 is 1000 nm or less. An uneven layer 20 is provided. Here, “microscopic” of the microprotrusions means that the microprotrusions are so small that they are arranged with an average interval d _AVG of 1000 nm or less.

  When the average distance between the microprotrusions 22 constituting the microprojection structure 21 is set to a specific value or less in the fine uneven layer 20, the inventors of the present invention have metal nanoparticles supported on the surface of the microprojection structure 21. No. 30 was found to be stably held and difficult to aggregate. In addition, since the surface of the specific microprojection structure 21 has a large surface area, it can carry more metal nanoparticles than a flat surface. As a result, the surface-enhanced Raman scattering measurement substrate according to the present invention can exhibit excellent SERS activity due to the metal nanoparticles, and is excellent in measurement sensitivity.

In the surface-enhanced Raman scattering measurement substrate 10 according to the present invention, the uneven surface shape of the microprojection structure 21 is appropriately adjusted according to the size, shape, arrangement, etc. of the microprojections 22 constituting the microprojection structure 21. Thus, the size, shape, and arrangement of the metal nanoparticles 30 supported on the surface of the microprojection structure 21 can be adjusted.
Each microprotrusion 22 constituting the microprotrusion structure 21 is formed so as to be planted on the fine concavo-convex layer 20, and the shape thereof is not particularly limited, but the metal nanoparticle 30 having a desired size is supported. Furthermore, from the point that the metal nanoparticles 30 can be arranged uniformly and stably, for example, the minute in the horizontal section when it is assumed that the metal nanoparticle 30 is cut along a horizontal plane perpendicular to the depth direction of the minute protrusion 22. It is preferable that the occupation ratio of the cross-sectional area of the material portion forming the protrusion 22 is continuously increased gradually from the top of the microprotrusion 22 toward the deepest portion, that is, a structure in which each microprotrusion is tapered. Specific examples of the shape of the minute protrusion 22 include those having a vertical cross-sectional shape such as a semicircular shape, a semi-elliptical shape, a triangular shape, a parabolic shape, and a bell shape. The plurality of microprojections 22 may have the same shape or different shapes. Moreover, it is preferable from the point of the formation property of a metal nanoparticle that the top of a microprotrusion has a curved surface.
Further, the ratio of the major axis to the minor axis (major axis / minor axis) of the horizontal cross section when it is assumed that the microprojections are cut in a horizontal plane perpendicular to the depth direction is 1 or more and 1.5 from the point of increasing the surface area. Or less, more preferably 1 or more and 1.2 or less.

In the microprojection structure 21, the average d _AVG of the distance between the microprojections 22 (d in FIG. 1, hereinafter sometimes referred to as “distance between adjacent projections d”) is 1000 nm or less, and metal Although it will not specifically limit if it is larger than the average particle diameter of the nanoparticle 30, It is preferable that it is 500 nm or less, It is more preferable that it is 380 nm or less, It is still more preferable that it is 200 nm or less. As a result, the stability of the metal nanoparticles 30 supported on the surface of the microprojection structure 21 is improved.
The average d _AVG of the distance between the microprotrusions 22 is not particularly limited as long as it is larger than the average particle diameter of the metal nanoparticles, but is usually 50 nm or more.
The adjacent minute protrusions related to the distance d between the adjacent protrusions are so-called adjacent minute protrusions, which are the protrusions that are in contact with the bottom part of the minute protrusion that is the base part. The fine concavo-convex layer used in the present invention has a polygonal structure surrounding each microprojection in a plan view when a line segment is created so that the microprojections are closely arranged so as to sequentially follow the valley portions between the microprojections. A mesh-like pattern formed by connecting a large number of shape regions is produced. The adjacent minute protrusions related to the distance d between the adjacent protrusions are protrusions that share a part of the line segments constituting the mesh pattern.

Further, the microprojection group 22 constituting the microprojection structure 21 includes microprojections having a plurality of vertices (hereinafter sometimes referred to as “multimodal microprojections”). good. In the present invention, the surface area of the microprojection structure 21 is further increased by including multimodal microprojections in the microprojection group. Particles 30 can be carried. Note that a microprojection having only one vertex may be referred to as a “unimodal microprojection” in comparison with a multimodal microprojection. In addition, each convex portion that forms each vertex related to a multi-peak microprojection or a single-peak microprojection is appropriately referred to as a “peak”.
Multi-modal micro-projections are relatively thicker than the unimodal micro-protrusions, with the thickness of the hem portion relative to the dimensions near the apexes, and because the external force is distributed and received at more apexes. It is considered that the external force applied to each apex can be reduced so that the microprojections are hardly damaged. Therefore, the surface-enhanced Raman scattering measurement substrate 10 of the present invention has multi-peaked microprojections as the microprojections 22 constituting the microprojection structure 21, thereby improving the mechanical strength and scratch resistance.

The height H of the microprotrusions (H in FIG. 1) may be set as appropriate. Among them, it is preferable to select the height H of the microprojections so that the aspect ratio of the microprojections (average projection height H _AVG / average adjacent projection spacing d _AVG ) is 0.8 to 2.5, It is more preferable to select so that it may become 0.8-2.1.
The average _{H AVG} height H of the fine protrusions 22 is preferably 1μm or less, preferably further 500nm or less, is preferably even more 50～350Nm, particularly to be 100~250nm preferable.
Here, the height H of each microprotrusion 22 refers to the height of a peak (the highest peak) having the highest height at the top. In the case of a single-peak microprojection, the height of the only peak at the top is the projection height of the microprojection. In the case of multimodal microprotrusions, the height of the microprotrusions is defined as the height of the highest peak among a plurality of ridges sharing the ridge at the top.

In the present invention, the mean value H _AVG average value d _AVG and height H of the minute projection 22 of the distance d between the fine protrusions 22 is measured by the following method.
(1) First, an in-plane arrangement of projections (planar shape of the projection arrangement) is detected using an atomic force microscope (AFM) or a scanning electron microscope (SEM).

  (2) Subsequently, a maximum point of the height of each protrusion (hereinafter simply referred to as a maximum point) is detected from the obtained in-plane arrangement. There are various methods for obtaining the maximum point, such as a method of sequentially comparing the planar view shape and the enlarged photograph of the corresponding cross-sectional shape to obtain the maximum point, and a method of obtaining the maximum point by image processing of the plan view enlarged photo. Can be applied.

  (3) Next, a Delaunay diagram with the detected maximum point as a generating point is created. Here, Delaunay diagram is obtained by dividing the Voronoi region adjacent to the Voronoi region when the Voronoi division is performed with each local maximum as the generating point, and connecting the adjacent generating points with line segments. This is a net-like figure made up of triangular aggregates. Each triangle is called a Delaunay triangle, and a side of each triangle (a line segment connecting adjacent generating points) is called a Delaunay line. FIG. 3 is a diagram in which a Delaunay diagram (a diagram represented by a white line segment) is superimposed on a schematic diagram of an enlarged photograph in plan view.

  (4) Next, the frequency distribution of the line segment length of each Delaunay line, that is, the frequency distribution of the distance between adjacent maximum points (distance between adjacent protrusions) is obtained. In addition, when there is a groove-like recess at the top of the protrusion, or when the top is split into a plurality of peaks, from the obtained frequency distribution, the microstructure in which there is a recess at the top of such protrusion, The data resulting from the fine structure in which the top part is divided into a plurality of peaks is removed, and only the data of the projection body itself is selected to create a frequency distribution.

  Specifically, a fine structure in which a concave portion exists on the top of the protrusion, or a fine structure related to a fine protrusion (multi-modal micro protrusion) in which the top is divided into a plurality of peaks has such a fine structure. The distance between adjacent protrusions is clearly different from the numerical range in the case of non-protruding microprotrusions (single-peak microprotrusions). Thus, by removing the corresponding data using this feature, only the data of the projection body itself is selected and the frequency distribution is detected. More specifically, for example, about 5 to 20 adjacent single-peaked microprojections are selected from an enlarged photograph of the microprojections (group) in plan view, and the value of the distance between the adjacent projections is sampled. The frequency distribution is excluded by excluding values that are clearly out of the numerical range obtained by sampling (usually, data having a value of 1/2 or less of the average distance between adjacent protrusions obtained by sampling). To detect.

(5) The frequency distribution of the distance d between adjacent protrusions thus determined is regarded as a normal distribution, and the average value d _AVG and the standard deviation σ _d are determined. The standard deviation σ _d is not particularly limited, but is preferably 10 nm to 100 nm because polarization dependency is reduced.

By applying the same method, the average value H _AVG and the standard deviation σ _H of the height H of the microprojections are obtained. First, the relative height difference of each local maximum point position from a specific reference position is acquired from the local maximum point obtained by the above (2) to form a histogram. An average value _HAVG of the protrusion height is obtained from the frequency distribution by the histogram. In the histogram of the protrusion height H, in the case of a multi-peak microprotrusion, the plurality of data are mixed for one protrusion due to having a plurality of vertices. In this case, the frequency distribution is obtained by adopting the vertex having the highest height from among the plurality of vertices belonging to the same microprotrusion at the heel (base) portion as the protrusion height of the microprotrusion.

  The reference position for measuring the height of the microprojections is the base position of the projection, that is, the valley bottom (minimum point of height) between the adjacent microprojections is used as the reference for the height 0. However, when the height of the valley bottom itself varies depending on the location, for example, when the envelope surface connecting the valley bottoms between the microprotrusions has a concavo-convex shape with a large period compared to the distance between adjacent protrusions of the microprotrusions, etc. (1) First, the average value of the height of each valley bottom measured from the surface or the back surface of the transparent substrate or the surface on the side opposite to the side where the microprojection structure of the micro uneven surface is present, Calculate within the area sufficient to converge. (2) Next, a surface having the average height and parallel to the surface or the back surface of the transparent substrate or the surface opposite to the surface on which the microprojection structure of the fine uneven layer is present is used as a reference surface. Think. (3) Then, the height of each microprotrusion from the reference surface is calculated by setting the reference surface to a height of 0 again.

When the microprotrusions in the microprotrusion structure are irregularly arranged, the average inter-protrusion distance _dAVG determined as described above may be 1000 nm or less.
On the other hand, when the microprotrusions in the microprotrusion structure are regularly arranged at a constant period, the standard deviation σ _{d of the} distance d between adjacent protrusions is 0, which matches the period p of the microprotrusion array. d _AVG = p.
Examples of the microprojections in the case where the microprojections forming the surface of the microprojection structure are regularly arranged at a constant period include, for example, a hexagonal lattice, a quasi-hexagonal lattice, a tetragonal lattice, or a quasi-tetragonal lattice And the like periodically arranged in a shape.
Here, the hexagonal lattice refers to a regular hexagonal lattice, and the quasi-hexagonal lattice refers to a distorted regular hexagonal lattice unlike a regular hexagonal lattice. Further, the tetragonal lattice refers to a regular tetragonal lattice, and the quasi-tetragonal lattice refers to a distorted regular tetragonal lattice unlike the regular tetragonal lattice.
To be arranged periodically in a hexagonal lattice means to be periodically arranged in a regular hexagonal lattice pattern, and to be arranged periodically in a quasi-hexagonal lattice, for example, an arrangement of microprojections Examples include those periodically arranged in a hexagonal lattice pattern stretched in the direction and distorted. In addition, the arrangement | sequence of a microprotrusion may meander not only in linear form.
When the microprojections forming the surface of the microprojection structure are irregularly arranged, the microprojections include all the microprojections forming the surface of the microprojection structure irregularly arranged. However, it may include a part of minute protrusions regularly arranged at a constant period.
In the present invention, each microprojection forming the surface of the microprojection structure is not particularly limited, but it is preferable that the microprojections are irregularly arranged. When the microprojections are regularly arranged, the regular structure may act as a diffraction grating and the Raman excitation light may be diffracted unnecessarily, but the microprojections are irregularly arranged. This is because unnecessary diffraction of the Raman excitation light can be prevented.

The fine concavo-convex layer preferably has an inorganic oxide layer on the surface on the microprojection structure side. FIG. 2 shows a surface-enhanced Raman scattering measurement substrate 10 ′ in which the surface of the fine concavo-convex layer 20 on the side of the microprojection structure 21 is made of an inorganic oxide layer 25.
Since the surface of the fine concavo-convex layer 20 on the side of the microprojection structure 21 is composed of the inorganic oxide layer 25, even when the fine concavo-convex layer 20 contains a resin, the enhancement of the spectrum of the resin by the metal nanoparticles 30 is prevented. Thereby, the measurement performance of the substrate for surface enhanced Raman scattering measurement according to the present invention is further improved.
The material of the inorganic oxide layer 25 is not particularly limited, but is preferably a material having no Raman activity or weak, for example, titanium oxide (TiO ₂ ), alumina (Al ₂ O ₃ ), zirconia (ZrO ₂ ). ), Tin oxide, zinc oxide, silicon dioxide, and amorphous materials thereof.
In addition, the said inorganic oxide layer is not restricted to the structure which consists of a single layer, You may have the structure by which the several layer was laminated | stacked.

  The thickness of the inorganic oxide layer 25 is not particularly limited as long as it is appropriately adjusted so that the uneven structure of the microprojection structure 21 is maintained even after the inorganic oxide layer 25 is formed. The thickness of the inorganic oxide layer 25 is preferably in the range of 1 nm to 30 nm, for example. The thickness can be measured, for example, by observing an electron micrograph such as TEM, STEM, or SEM of a vertical section obtained by cutting the surface-enhanced Raman scattering measurement substrate 10 according to the present invention in the thickness direction.

  Although the thickness of the fine uneven | corrugated layer 20 is not specifically limited, As an example, it can be 10-1000 micrometers. In this case, the thickness of the fine concavo-convex layer 20 refers to the top of the microprojections 22 forming the microprojection structures 21 of the microrelief layer 20 from the interface on the side where the microprojections 21 are not present. It means the height t1 along the normal direction nd to the film surface of the substrate 10 for surface enhanced Raman scattering measurement up to 23.

<Method for forming fine uneven layer>
As the fine concavo-convex layer 20 having the microprojection structure 21 on the surface used in the present invention, a commercial product on which the desired microprojection structure 21 is formed may be used. On the other hand, when the fine uneven layer 20 is formed, there is no particular limitation as long as it is a method capable of forming the above-described microprojection structure 21.
For example, a method for forming a fine uneven layer 20 having a fine protrusion structure 21 in which a plurality of fine protrusions 22 made of a cured product of a resin composition for a fine uneven layer are arranged in close contact with one surface of a transparent substrate 11. As a specific example of the above, first, the resin composition for fine uneven layer is applied on the transparent substrate 11 to form a coating film, and the uneven shape of the original plate for forming a microprojection structure having a desired uneven shape is Examples thereof include a method of forming the microprojection structure 21 by curing the resin composition after forming the coating film of the resin composition, and peeling the original plate for forming the microprojection structure.
The concave / convex shape of the original plate for forming the microprojection structure is a shape in which a large number of micropores are densely formed and corresponds to the shape of the microprojection structure 21.
The method of shaping the concave / convex shape of the original plate for forming a microprojection structure into a resin composition for a fine concave / convex layer and curing the resin composition can be appropriately selected according to the type of the resin composition.
Moreover, you may form the fine uneven | corrugated layer 20 in one surface of the transparent base material 11, as shown in FIG. In this case, the transparent substrate 11 serves as a support for the fine uneven layer 20. Alternatively, after the microprojection structure 21 is formed by curing the resin composition, the transparent base material used for production is peeled off as necessary, and only the fine uneven layer 20 as shown in FIG. Good.

  In addition, when the inorganic oxide layer 25 is formed on the surface of the microprojection structure 21, the formation method is not particularly limited. For example, the uneven shape of the original plate for forming the microprojection structure having a desired uneven shape. After forming the coating film of the resin composition and curing the resin composition, on the surface of the cured resin composition formed with the uneven shape, for example, a sputtering method, a CVD method, a sol-gel method, Examples thereof include a method of forming the inorganic oxide layer 25 by a MOD method (Metal Organic Deposition).

(Transparent substrate)
As the transparent substrate 11, a known transparent substrate can be appropriately selected and used, and is not particularly limited. Examples of the material used for the transparent substrate 11 include a transparent resin. Examples of the transparent resin include acetyl cellulose resins such as triacetyl cellulose, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, olefin resins such as polyethylene and polymethylpentene, acrylic resins, polyurethane resins, and polyethers. Examples include sulfone, polycarbonate, polysulfone, polyether, polyetherketone, acrylonitrile, methacrylonitrile, cycloolefin polymer, and cycloolefin copolymer. Examples of materials used for the transparent substrate 11 include glass such as soda glass, potassium glass, alkali-free glass, and lead glass, ceramics such as lead lanthanum zirconate titanate (PLZT), quartz, and fluorite. Examples thereof include transparent inorganic materials.

  Although the thickness of the transparent base material 11 can be suitably set according to the use of the substrate 10 for surface-enhanced Raman scattering measurement and is not particularly limited, it is usually 10 to 5000 μm, and the transparent base material 11 is in the form of a roll. It may be either supplied, not bent to the extent that it can be wound, but curved by applying a load, or not completely bent.

  The transparent substrate 11 preferably has a transmittance in the visible light region of 80% or more, and more preferably 90% or more. Here, the transmittance of the transparent substrate can be measured by JISK7361-1 (Plastic—Testing method of total light transmittance of transparent material).

  The configuration of the transparent substrate 11 is not limited to a configuration composed of a single layer, and may have a configuration in which a plurality of layers are stacked. When it has the structure by which the several layer was laminated | stacked, the layer of the same composition may be laminated | stacked, and the several layer which has a different composition may be laminated | stacked. Further, a primer layer for improving the adhesion between the transparent substrate 11 and the fine uneven layer 20 and thus improving the wear resistance may be formed on the transparent substrate 11. This primer layer preferably has adhesion to both the transparent substrate 11 and the fine uneven layer 20 and is transparent in terms of visible optics. As a material for the primer layer, for example, a material selected from a fluorine-based coating agent, a silane coupling agent and the like can be used as appropriate. Examples of commercially available fluorine-based coating agents include Fluorosurf FG-5010Z130 manufactured by Fluoro Technology, and examples of commercially available silane coupling agents include Durasurf Primer DS-PC-3B manufactured by Harves. Is mentioned.

(Resin composition for fine uneven layer)
In the present invention, the fine uneven layer 20 is not particularly limited. For example, the fine uneven layer 20 can be a layer containing a resin, and can be formed by curing a resin composition.
The resin composition for fine concavo-convex layers contains at least a resin and, if necessary, other components such as a polymerization initiator. The resin used in the resin composition is not particularly limited. For example, ionizing radiation curable resins such as acrylate-based, epoxy-based, and polyester-based resins, and thermosetting such as acrylate-based, urethane-based, epoxy-based, and polysiloxane-based resins. Various materials such as thermoplastic resins such as curable resins, acrylate-based, polyester-based, polycarbonate-based, polyethylene-based, and polypropylene-based resins, and molding resins in various cured forms can be used. Moreover, you may contain a non-reactive polymer. The ionizing radiation means electromagnetic waves or charged particles having energy that can be cured by polymerizing molecules. For example, all ultraviolet rays (UV, UV-B, UV-C), visible rays, gamma rays, X Examples thereof include an electron beam and an electron beam.

As the resin, an ionizing radiation curable resin is preferable because it is excellent in moldability and mechanical strength. The ionizing radiation curable resin used in the present invention is a mixture of a monomer or a polymer having radically polymerizable and / or cationically polymerizable bonds in a molecule as appropriate, and ionized using a suitable polymerization initiator. It is cured by radiation. Further, in the present invention, being excellent in moldability means that it can be accurately molded into a desired shape.
Especially, it is preferable that the resin composition for fine uneven | corrugated layers contains at least 1 sort (s) chosen from the group which consists of an acrylate type, an epoxy type, and a polyester type ionizing radiation curable resin, and also has an acryloyl group and / or a methacryloyl group. It is preferable to include at least one selected from acrylate-based ionizing radiation curable resins.

  The fine concavo-convex layer resin composition may appropriately use a solvent from the viewpoint of imparting coatability and the like, and further, if necessary, a polymerization initiator, a release agent, a photosensitizer, an antioxidant. Further, it may contain a polymerization inhibitor, a crosslinking agent, an infrared absorber, an antistatic agent, a viscosity modifier, a silane coupling agent, and the like.

(Original plate for forming microprojections)
The original plate for forming the microprojection structure is not particularly limited as long as it is not deformed and worn when repeatedly used, and may be made of metal or resin, Usually, metal is preferably used because it is excellent in deformation resistance and wear resistance.
The surface having the concavo-convex shape of the original plate for forming a microprojection structure is not particularly limited, but is preferably made of aluminum from the viewpoint of being easily oxidized and easily processed by anodization.
Specifically, the original plate for forming the microprojection structure has high purity by sputtering or the like directly on the surface of a metal base material such as stainless steel, copper, or aluminum, or through various intermediate layers. An aluminum layer is provided, and the aluminum layer is formed with an uneven shape. Prior to providing the aluminum layer, the surface of the base material may be made into a super mirror surface by an electrolytic composite polishing method in which electrolytic elution action and abrasion action by abrasive grains are combined.
Examples of a method for forming a concavo-convex shape on the original plate for forming a microprojection structure include, for example, an anodic oxidation step of forming a plurality of micropores on the surface of the aluminum layer by an anodic oxidation method, and etching the aluminum layer. A first etching step for forming a tapered shape in the opening of the microhole, and a second for enlarging the hole diameter of the microhole by etching the aluminum layer at an etching rate higher than the etching rate of the first etching step. It can be formed by sequentially repeating the etching process.
When forming a concavo-convex shape on an original plate for forming a microprojection structure, the purity (impurity amount), crystal grain size, anodizing treatment and / or etching treatment conditions of the aluminum layer are appropriately adjusted to obtain a desired shape. It can be a shape. In the anodic oxidation treatment, more specifically, the micropores can be produced to the desired depth and shape by managing the liquid temperature, the applied voltage, the time for the anodic oxidation, and the like.

Moreover, examples of the shape of the original plate for forming a microprojection structure include a flat plate shape and a roll shape, and are not particularly limited, but a roll shape is preferable from the viewpoint of improving productivity. In the present invention, it is preferable to use a roll-shaped mold (hereinafter sometimes referred to as “roll mold”) as the original plate for forming the microprojection structure.
As the roll mold, for example, as described above, a cylindrical metal material is used as a base material, and the aluminum layer provided on the peripheral side surface of the base material directly or through various intermediate layers, as described above. In other words, the concavo-convex shape is produced by repeating the anodizing treatment and the etching treatment.

  FIG. 4 shows an example of a method for forming the fine concavo-convex layer 20 using an ultraviolet curable resin composition as the resin composition for forming the fine concavo-convex layer 20 and using a roll die as the original plate for forming the microprojection structure 21. Indicates. In this manufacturing method, first, in the resin supplying step, an uncured and liquid ultraviolet curable resin composition that forms a receiving layer 20 ′ that becomes the fine uneven layer 20 is formed on the transparent base material 11 in the form of a strip by a die 31. Apply. In addition, about application | coating of an ultraviolet curable resin composition, not only the case by the die | dye 31 but various methods are applicable. Subsequently, the transparent substrate 11 is pressed and pressed against the peripheral side surface of the roll die 32 which is a shaping die by the pressing roller 33, thereby bringing the uncured receiving layer 20 ′ into close contact with the transparent substrate 11. At the same time, the ultraviolet curable resin composition constituting the receiving layer 20 ′ is sufficiently filled in the concave portion having a minute uneven shape formed on the peripheral side surface of the roll mold 32. In this state, the ultraviolet curable resin composition is cured by irradiating with ultraviolet rays, thereby forming the fine uneven layer 20 having the microprojection structure 21 on the surface of the transparent substrate 11. Subsequently, the transparent substrate 11 is peeled from the roll die 32 through the peeling roller 34 integrally with the hardened fine uneven layer 20. If necessary, an adhesive layer or the like is laminated on the transparent substrate 11 and then cut into a desired size. Thereby, the laminated body of the fine uneven | corrugated layer 20 in which the microprojection structure 21 of the desired shape was formed, and the transparent base material 11 is mass-produced efficiently.

In order to mix multi-peak microprojections and monomodal micro-protrusions, it must be realized by varying the micro-hole intervals of the micro-projection structure forming original plate produced in the anodizing process. Can do. Multi-modal microprotrusions are created by micropores having a concave portion corresponding to the top of the microprotrusions, and such micropores are produced by etching processing. It is thought that they are formed integrally.
Also, the variation in the height of each microprojection is due to the variation in the depth of the microhole formed in the original plate for forming the microprojection structure. It can be said that this is due to variations in processing. In order to give the individual microprotrusions variations in height, it can be realized by increasing the variations in the anodizing process.

  Moreover, although the above-mentioned embodiment described the case where the fine uneven | corrugated layer 20 was formed on the film-shaped transparent base material 11 by the shaping process using a roll metal mold | die, this invention is not limited to this, Transparent base Depending on the shape of the material, the process and mold for the shaping process can be appropriately changed. For example, the fine concavo-convex layer can be formed on the sheet-like transparent substrate by a shaping process using a shaping mold having a flat plate shape or a specific curved shape.

<Metal nanoparticles>
In the surface-enhanced Raman scattering measurement substrate 10 according to the present invention, the metal nanoparticles 30 are supported on the surface of the microprojection structure 21. Here, in the present invention, the term “supporting” means that the particles are attached to the carrier. Specifically, the metal nanoparticles 30 are provided on the surface of the fine concavo-convex layer 20 on the microprojection structure 21 side. It means to have it attached. Various characteristics obtained in the surface-enhanced Raman scattering measurement substrate 10 according to the present invention are usually exhibited based on the metal nanoparticles 30 themselves.

  Although the said metal nanoparticle 30 is not specifically limited, It is preferable to arrange | position so that a hot site may be formed. Here, the hot site refers to a local strong electric field region formed by densely arranging the metal nanoparticles 30. In the hot site, the distance between the adjacent metal nanoparticles 30 is preferably smaller than the average particle diameter of the adjacent metal nanoparticles 30, for example, the distance between the metal nanoparticles 30 is 20 nm or less. It is preferable that the thickness is 10 nm or less. In addition, the distance between the adjacent metal nanoparticles 30 refers to the distance between the gaps where the adjacent metal nanoparticles 30 are closest to each other.

For example, as shown in FIGS. 1 and 2, the metal nanoparticles 30 may be arranged in a state of being uniformly arranged on the surface of the microprojection structure 21, but the distribution state of the metal nanoparticles 30 is particularly limited. For example, the metal nanoparticles 30 may be more densely arranged by the valleys 24 and the tops 23 of the microprojections 22 than the side surfaces of the microprojections 22. Among them, hot sites are formed so that the number (density) of hot sites per unit surface area is preferably 100 to 10,000 / μm ² , more preferably 1000 to 10,000 / μm ² from the viewpoint of excellent measurement sensitivity. It is preferable.

Moreover, the average distance between the adjacent metal nanoparticles 30 is not particularly limited, but is preferably 20 nm or less, more preferably 10 nm or less from the viewpoint of easily forming hot sites and improving the electric field enhancement effect. preferable.
The standard deviation of the distance between adjacent metal nanoparticles 30 is preferably 10 nm or less, and more preferably 5 nm or less, from the viewpoint of suppressing variations in Raman scattering intensity.

In particular, the metal nanoparticles 30 are arranged in a state of being uniformly arranged as shown in FIGS. 1 and 2, so that hot sites are easily formed, the electric field enhancement effect is improved, and the Raman scattering intensity is increased. It is preferable from the viewpoint of suppressing the variation of.
From the same viewpoint, it is more preferable that the metal nanoparticles 30 are not deposited and are arranged in a single layer state.

The metal constituting the metal nanoparticle 30 carried by the surface-enhanced Raman scattering measurement substrate 10 according to the present invention has optical characteristics that are not exhibited in the case of a bulk when the particle diameter is present as a nanometer-order particle. Those exhibiting a certain Raman scattering enhancement effect are used. In the present invention, as described above, by supporting the metal nanoparticles 30 using the fine concavo-convex layer 20 having the microprojection structure 21, the metal nanoparticles 30 can stably exist as individual particles. Can do. Therefore, in this invention, it can use more suitably with respect to the metal nanoparticle 30 comprised from the metal which has the property of being easy to aggregate in the state of particle | grains. Further, considering that the characteristics unique to the metal nanoparticles 30 are utilized more effectively, the metal constituting the metal nanoparticles 30 has a peak wavelength of plasmon absorption in the visible light region when present as particles. It is preferable.
Considering these points, the metal nanoparticles 30 are preferably one or more metal nanoparticles selected from the group consisting of gold, silver, copper, platinum, palladium, nickel, and alloys thereof.
The average particle diameter of the metal nanoparticles 30 is not particularly limited as long as the metal nanoparticles 30 are stably supported by the microprojection structure 21 of the fine concavo-convex layer 20, but is within a range of, for example, 20 to 30 nm.

  In the present invention, the particle size of metal nanoparticles, the distance between particles, the number of particles, the particle density, and the like are obtained by, for example, TEM, STEM, SEM, etc. of the surface-enhanced Raman scattering measurement substrate 10 according to the present invention. It can be measured by observing. Specifically, these values can be measured using an image obtained by binarizing an electron micrograph using analysis software. FIG. 5A shows an example of a STEM image of the surface-enhanced Raman scattering measurement substrate according to the present invention. FIG. 5B shows the STEM image of FIG. The image which extracted only the metal nanoparticle by binarizing is shown. The particle diameter, the distance between particles, and the number of particles of the metal nanoparticles can be measured based on these images. Note that the analysis software used in FIG. 5B is ImageJ.

  The method for supporting the metal nanoparticles 30 on the surface of the microprojection structure 21 of the fine uneven layer 20 is not particularly limited, and various methods can be used. For example, sputtering method, ion plating method, vacuum deposition method, gas phase method (dry process) such as CVD method, ink jet printing method, screen printing method, gravure printing method, offset printing method, flexographic printing method, dispenser printing method, Examples thereof include solution coating methods (wet processes) such as a slit coating method, a die coating method, a doctor blade coating method, a wire bar coating method, a spin coating method, a dip coating method, and a spray coating method.

  In addition, as a result of extensive research conducted by the present inventors, from the viewpoint of more stably holding the metal nanoparticles 30, by attaching metal atoms to the surface of the microprojection structure using an evaporation method, It is preferable to support the metal nanoparticles 30 on the surface of the microprojection structure 21 of the fine concavo-convex layer 20 by the step of forming and supporting the particles. In addition, as a method of supporting the alloy nanoparticles, for example, an alloy deposition source containing two or more selected from the group consisting of gold, silver, copper, platinum, palladium, and nickel is used to form a microprojection structure by flash deposition. Examples thereof include a method of adhering to the surface of the body 21 and a method of performing co-evaporation using two or more kinds of vapor deposition sources. It is preferable to use alloy nanoparticles as the metal nanoparticles because surface plasmon resonance and particle stability can be adjusted.

As a method for forming and supporting the metal nanoparticles 30 on the surface of the microprojection structure 21, the vapor deposition method is preferable, and the vacuum vapor deposition method is particularly preferable.
In the case of the vacuum deposition method, a vacuum deposition apparatus provided with a vacuum exhaust system, an evaporation source, and a substrate holder is usually used.
As the vacuum exhaust system, a conventionally known high vacuum exhaust system may be used. For example, an oil rotary pump, a dry pump, or the like can be used as the roughing pump, and a roots pump or the like can be used as a booster pump if necessary. As the high vacuum pump, a diffusion pump, a cryopump, or the like can be used. When a diffusion pump is used, a cold trap at about −120 to −150 ° C. may be further provided.
The evaporation source has a heating source for heating and evaporating the metal. Examples of the heating source include resistance heating and electron beam heating.

For example, first, a member having the microprojection structure 21 on the surface is placed on the substrate holder so that the surface of the microprojection structure 21 faces the evaporation source. After the inside of the vacuum vessel of the vacuum evaporation apparatus is brought into a vacuum state of about 10 ⁻² to 10 ⁻³ Pa, the metal is heated so that the vapor pressure of the metal is about 1 to 10 ⁻² Pa in the evaporation source, and the minute Metal atoms may be attached to the surface of the protruding structure 21.

  Thus, according to the method for producing a surface-enhanced Raman scattering measurement substrate according to the present invention, the metal nanoparticles 30 can be stably supported as single particles by the vapor phase method, Unlike the method used, the surface of the metal nanoparticle 30 is not covered with a dispersant or the like, so that it can be produced by a simple method in one step and has high measurement sensitivity.

  In particular, the adhesion of metal atoms to the microprojection structure 21 is such that when the microprojection structure 21 is assumed to be a flat surface, the thickness of the metal laminated on the flat surface is preferably 40 nm or less. More preferably, it is carried out using a vapor deposition method in a state adjusted to be 20 nm or less. As a result, the metal nanoparticles 30 having a particle size that can be stably held can be formed on the microprojection structure 21 of the fine concavo-convex layer 20, and the metal nanoparticles 30 can be aggregated or deposited. Therefore, hot sites are easily formed.

<Modification>
Various modifications can be made to the above-described embodiment of the present invention. Hereinafter, an example of modification will be described. In the following description, the same reference numerals as those used for the corresponding parts in the above-described embodiment are used for the parts that can be configured in the same manner as in the above-described embodiment, and redundant description is omitted. To do.
For example, in the above-described embodiment, the surface-enhanced Raman scattering measurement substrate 10 has the microprojection structure 21 of the fine concavo-convex layer 20 only on one surface side, and a metal is formed on the microprojection structure 21. Although the example in which the nanoparticles 30 are arranged has been shown, the present invention is not limited to this. The surface-enhanced Raman scattering measurement substrate 10 has a microprojection structure 21 of a fine uneven layer 20 on both sides of one surface and the other surface, and metal nanoparticles on both microprojection structures 21. 30 may be arranged. Alternatively, the surface-enhanced Raman scattering measurement substrate 10 has the microprojection structures 21 of the fine uneven layer 20 on both sides of one surface side and the other surface side, and only on one microprojection structure body 21. Metal nanoparticles 30 may be arranged.
In the above-described embodiment, the surface-enhanced Raman scattering measurement substrate 10 includes the transparent substrate 11, the fine uneven layer 20, and the metal nanoparticles 30 (FIG. 1), and the fine uneven layer 20 Although the example (FIG. 2) which the surface of consists of the inorganic oxide layer 25 was shown, it is not restricted to these. The transparent base material 11 may be omitted from the surface-enhanced Raman scattering measurement substrate 10, or another layer may be added to the surface-enhanced Raman scattering measurement substrate 10, 10 ′.

<Application of surface-enhanced Raman scattering measurement substrate>
The surface-enhanced Raman scattering measurement substrate according to the present invention can be widely applied to spectroscopic analysis methods such as Raman spectroscopy and infrared spectroscopy, such as clinical examination, environmental monitoring, quality control, residual agricultural chemicals and flavoring. It can be applied to fields such as food inspection such as analysis of security and security inspection such as detection of dangerous goods.

Hereinafter, the present invention will be specifically described with reference to examples. These descriptions do not limit the present invention.
[Example 1]
(Preparation of fine uneven layer)
<Manufacture of original plate for forming microprojection structure>
A rolled aluminum plate having a purity of 99.50% is polished so that its surface has an irregular shape with a 10-point average roughness Rz of 30 nm and a period of 1 μm, and then formed in an electrolyte solution of 0.02 M oxalic acid aqueous solution. Anodization was performed for 120 seconds under conditions of a voltage of 40 V and 20 ° C. Next, as a first etching process, an etching process was performed for 60 seconds with the electrolytic solution after anodization. Subsequently, as the second etching treatment, a pore size treatment was performed with a 1.0 M phosphoric acid aqueous solution for 150 seconds. Furthermore, the said process was repeated and these were added and implemented 5 times in total. As a result, an anodized aluminum layer having fine irregularities formed on the aluminum substrate was formed. Finally, a fluorine mold release agent was applied and the excess mold release agent was washed to obtain an original plate for forming a microprojection structure.

<Preparation of resin composition for forming fine uneven layer>
A resin composition is prepared by dissolving 20 parts by mass of dipentaerythritol hexaacrylate (DPHA), 70 parts by mass of Aronix M-260 (manufactured by Toa Gosei Co., Ltd.), 10 parts by mass of hydroxyethyl acrylate, and 3 parts by mass of lucillin TPO in 300 parts by mass of ethyl acetate. A product was prepared.

<Formation of microprojection structure>
The fine concavo-convex layer-forming resin composition is applied and filled such that the fine concavo-convex surface of the microprojection structure-forming original plate is covered and the thickness of the fine concavo-convex layer after curing is 20 μm. A 80 μm thick triacetyl cellulose (TAC) film (manufactured by Fuji Film Co., Ltd.) was bonded obliquely as a transparent substrate, and the bonded body was pressed with a rubber roller under a load of 10 N / cm ² . After confirming that the uniform composition was applied to the entire original plate, ultraviolet rays were irradiated from the transparent substrate side with an energy of 2000 mJ / cm ² to cure the resin composition for forming a fine uneven layer. Then, it peeled from the original plate and obtained the laminated body of the transparent base material and the fine uneven | corrugated layer before inorganic oxide layer formation.

<Formation of inorganic oxide layer>
Sputtering equipment (SMD-750, ULVAC, Inc.) was used to sputter zirconium oxide on the fine irregular surface of the resulting laminate, and the thickness in the region from the top to the valley of each microprotrusion was An inorganic oxide layer composed of a continuous layer of zirconium oxide within a range of 10 to 20 nm was formed. Subsequently, titanium oxide is sputtered at 35 ° C. using a sputtering apparatus (ULMD, SMD-750), and the thickness in the region from the top to the valley of each fine protrusion is within a range of 10 to 20 nm. The inorganic oxide layer which consists of a continuous layer of was formed. The thickness of the inorganic oxide layer was measured by observing a STEM electron micrograph of a vertical cross section obtained by cutting the laminate after forming the inorganic oxide layer in the thickness direction.
The microprojection structure provided on the fine uneven layer after the formation of the inorganic oxide layer has a structure in which the distance between adjacent microprojections is 100 nm, the average microprojection height is 200 nm, and each microprojection is tapered. there were.

(Adhesion of metal atoms by vapor deposition)
On the concavo-convex surface of the concavo-convex structure article on which the inorganic oxide layer is formed, using a vacuum deposition apparatus (VPC-410, manufactured by ULVAC, Inc.), the concavo-convex degree is 8 × 10 ⁻⁶ Torr (1 × 10 ⁻³ Pa). Gold was vapor-deposited with an equivalent film thickness of 5 nm on a flat surface such that the film thickness was 5 nm when the film was formed on the surface of a lithographic material having the same area in plan view as the area on the surface. This was attached to a slide glass (manufactured by Matsunami Glass Co., Ltd., S1221) via an adhesive (manufactured by Panac, product name Panaclean PDR5) to obtain a surface enhanced Raman scattering measurement substrate of Example 1. When the STEM image of the substrate for surface enhanced Raman scattering measurement obtained in Example 1 was confirmed, metal nanoparticles having an average particle diameter of 17.3 nm were formed, and the average distance between metal nanoparticles was 3.5 nm. The standard deviation of the distance between the metal nanoparticles was 2.5 nm, and the number density of hot sites was 4900 / μm ² .

[Example 2]
A surface-enhanced Raman scattering measurement substrate of Example 2 was obtained in the same manner as in Example 1 except that silver was used instead of gold in the deposition of metal atoms by vapor deposition. When the STEM image of the substrate for surface enhanced Raman scattering measurement obtained in Example 2 was confirmed, metal nanoparticles having an average particle diameter of 5.3 nm were formed, and the average distance between the metal nanoparticles was 9.4 nm. The standard deviation of the distance between the metal nanoparticles was 8.0 nm, and the number density of hot sites was 3700 / μm ² .

[Comparative Example 1]
A slide glass (manufactured by Matsunami Glass Co., Ltd., S1221) was used as it was to make an article of Comparative Example 1.

[Comparative Example 2]
Gold on the slide glass (manufactured by Matsunami Glass Co., Ltd., S1221) using a vacuum evaporation apparatus (VPC-410, manufactured by ULVAC, Inc.) with a vacuum degree of 8 × 10 ⁻⁶ Torr (1 × 10 ⁻³ Pa) and a film thickness of 15 nm. The article of Comparative Example 2 was obtained by vapor deposition. A gold thin film was uniformly formed on the surface.

[Comparative Example 3]
An article of Comparative Example 3 was obtained in the same manner as Comparative Example 2 except that silver was deposited in a film thickness of 15 nm instead of gold. A silver thin film was uniformly formed on the surface.

<Evaluation of Raman scattering>
Rhodamine 6G ethanol solution having a concentration of 158 μM was prepared by dissolving 0.0076 g of rhodamine 6G (manufactured by Lambda Physik) in 100 ml of ethanol. In this solution, the surface-enhanced Raman scattering measurement substrate obtained in Example 1 and Example 2 and the articles of Comparative Example 1, Comparative Example 2 and Comparative Example 3 were dipped, pulled up and air-dried. The Raman spectrum of rhodamine 6G in each article after air drying was measured with a microscopic laser Raman spectrometer (HR800, manufactured by Horiba, Ltd.). The excitation laser wavelength at the time of measurement was 633 nm. FIG. 6 shows a plot of Example 1, Comparative Example 1, and Comparative Example 2 as measurement results, and FIG. 7 shows a plot of Example 2, Comparative Example 1, and Comparative Example 3.
Peak attributable to rhodamine 6G is the Raman shift ^{612cm -1, 776cm -1, 1193cm -1} , 1349cm -1, 1511cm -1, appears at 1600 cm ^-1. In Example 1 and Example 2, an increase in the peak derived from rhodamine 6G was confirmed.

(Summary of results)
The surface-enhanced Raman scattering measurement substrates obtained in Examples 1 and 2 have a microprojection structure in which a plurality of microprojections are closely arranged and the average distance between adjacent microprojections is 1000 nm or less. According to the present invention, the fine uneven layer has metal nanoparticles having an average particle diameter smaller than the average distance between the microprotrusions, and the metal nanoparticles are supported on the surface of the microprotrusion structure. It was a substrate for surface enhanced Raman scattering measurement, and could be manufactured by a simple method in one step. In Examples 1 and 2, an increase in Raman scattering intensity was confirmed and the measurement sensitivity was higher than in each Comparative Example.
On the other hand, in Comparative Examples 1 to 3, metal nanoparticles were not supported on the substrate surface, and the measurement sensitivity was poor.

DESCRIPTION OF SYMBOLS 10 Surface-enhanced Raman scattering measurement substrate 10 'Surface-enhanced Raman scattering measurement substrate 11 Transparent base material 20 Fine uneven | corrugated layer 20' Receptive layer 21 Microprotrusion structure 22 Microprotrusion 23 Top part 24 Valley part 25 Inorganic oxide layer 30 Metal nano Particle 31 Die 32 Roll mold 33 Pressing roller 34 Peeling roller

Claims (6)

A plurality of minute projections are closely spaced, average 1000nm der following distance between adjacent said microprojection is, in horizontal cross section, assuming that was cut in a horizontal plane perpendicular to the depth direction of the microprojections The cross-sectional area occupancy rate of the material portion forming the microprotrusions has a structure that gradually increases gradually from the top of the microprotrusions toward the deepest portion, and is relative to the average distance between the adjacent microprotrusions A fine concavo-convex layer having a microprojection structure in which the average ratio of the heights of the microprojections is 0.8 to 2.5, and metal nanoparticles having an average particle size smaller than the average distance between the microprojections And
A substrate for surface enhanced Raman scattering measurement, wherein the metal nanoparticles are supported on the surface of the microprojection structure.   The surface-enhanced Raman scattering measurement substrate according to claim 1, wherein the surface of the fine uneven layer is composed of an inorganic oxide layer.   The surface enhancement according to claim 1 or 2, wherein the metal nanoparticles are one or more metal nanoparticles selected from the group consisting of gold, silver, copper, platinum, palladium, nickel, and alloys thereof. A substrate for Raman scattering measurement. A plurality of minute projections are closely spaced, average 1000nm der following distance between adjacent said microprojection is, in horizontal cross section, assuming that was cut in a horizontal plane perpendicular to the depth direction of the microprojections The cross-sectional area occupancy rate of the material portion forming the microprotrusions has a structure that gradually increases gradually from the top of the microprotrusions toward the deepest portion, and is relative to the average distance between the adjacent microprotrusions Preparing a fine concavo-convex layer having a microprojection structure in which the average ratio of the heights of the microprojections is 0.8 to 2.5 ;
A method for producing a surface-enhanced Raman scattering measurement substrate, comprising a step of forming and supporting metal nanoparticles by attaching metal atoms to the surface of the microprojection structure using a vapor deposition method.   The method for producing a surface-enhanced Raman scattering measurement substrate according to claim 4, wherein the vapor deposition method is adjusted such that the thickness of a vapor deposition film formed by metal atoms adhering to a flat surface is 40 nm or less.   The surface enhancement according to claim 4 or 5, wherein the metal nanoparticles are one or more metal nanoparticles selected from the group consisting of gold, silver, copper, platinum, palladium, nickel, and alloys thereof. A method for manufacturing a substrate for Raman scattering measurement.