Signal enhancement structure and measuring method with signal enhancement

Abstract

A signal enhancement structure is provided for amplifying the signal of an analyte. The signal enhancement structure includes a plurality of nanowires stacked in a first direction, a second direction, and a third direction, wherein the nanowires extend in at least two directions, and particles of the analyte fall onto these nanowires or into the gaps between the nanowires. A method for measuring the enhanced signal is also proposed.

Description

Structure and measurement methods of enhanced signals This invention relates to a structure for enhancing signals, a method for manufacturing such a structure, and a method for measuring the enhanced signals. Raman spectroscopy is a type of vibrational spectroscopy. Its principle is to use a laser light source with a fixed wavelength to excite the sample. When the excitation light interacts with the sample particles, if energy exchange occurs after the photon collides with the particle, the photon transfers some energy to the sample particle or obtains some energy from the sample particle, thereby changing the frequency of the light. This change is called the Raman shift. Raman spectroscopy offers advantages such as requiring no sample pretreatment and being non-destructive, while providing instantaneous detection and results. Furthermore, Raman spectroscopy can be performed using microscopy, achieving sub-micron resolution for more precise analysis. It also boasts high selectivity, high sensitivity, and high mobility. Raman spectroscopy can be used in food testing, biomedical testing, environmental monitoring, and drug detection. Conversely, photoluminescence spectroscopy, particularly fluorescence spectroscopy, also offers the advantages of requiring no sample pretreatment and being non-destructive, and can similarly be used for various detection methods. Raman spectroscopy or photoluminescence spectroscopy sometimes produce insufficient signals, making it difficult to obtain good detection results. The present invention provides a structure for enhancing signals, which can be used to detect analytes of different particle sizes. The present invention provides a method for fabricating a structure to enhance signals, which can be used to produce analytes for detecting particles of different sizes. One embodiment of the present invention provides a signal enhancement structure for enhancing the signal of a test object. The signal enhancement structure includes a plurality of nanowires stacked in a first direction, a second direction, and a third direction, wherein the nanowires extend in at least two directions, and particles of the test object fall on the nanowires or in the gaps between the nanowires. An embodiment of the present invention provides a method for fabricating a signal enhancement structure, comprising: spraying a plurality of nanowires dispersed in a solvent onto a surface along with the solvent to form a first nanowire layer; and after the solvent in the first nanowire layer evaporates, spraying the plurality of nanowires dispersed in the solvent onto the first nanowire layer again along with the solvent to form a second nanowire layer. One embodiment of the present invention provides a signal enhancement structure for enhancing the signal of a test object. The signal enhancement structure includes a plurality of nanowires stacked in a first direction, a second direction, and a third direction, wherein these nanowires extend in at least two directions, and the nanowires have various angles perpendicular to the first direction, the second direction, and the third direction. Particles of the test object fall onto these nanowires, in the gaps between these nanowires, or the nanowires are on the test object. These nanowires are stacked in the third direction to form a film, where the third direction is the thickness direction of the film. The first and second directions are both perpendicular to the third direction, and the thickness of the film in the third direction is in the range of 350 nm to 550 nm. An embodiment of the present invention provides a signal enhancement measurement method, comprising: dropping or spraying a plurality of nanowires dispersed in a solvent onto a surface of a test object to form a film layer on the test object, wherein the thickness of the film layer falls in the range of 350 nanometers to 550 nanometers; and measuring at least one of the Raman spectrum and photoluminescence spectrum of the test object, the signal of which is enhanced by the nanowires. An embodiment of the present invention provides a signal enhancement measurement method, comprising: mixing a analyte with a plurality of nanowires dispersed in a solvent; dropping or spraying the analyte onto a substrate along with the nanowires dispersed in the solvent to form a film layer on the substrate, wherein the thickness of the film layer falls in the range of 350 nanometers to 550 nanometers; and measuring at least one of the Raman spectrum and photoluminescence spectrum of the analyte, the signal of which is enhanced by the nanowires. An embodiment of the present invention provides a signal enhancement measurement method, comprising: dropping or spraying a plurality of nanowires dispersed in a solvent onto a substrate to form a film layer on the substrate, wherein the thickness of the film layer falls within the range of 350 nanometers to 550 nanometers; dropping or spraying a analyte onto the film layer; and measuring at least one of the Raman spectrum and photoluminescence spectrum of the analyte, wherein the signal is enhanced by the nanowires. In the signal enhancement structure of the embodiments of the present invention, since these nanowires are stacked in the first, second, and third directions, the particles of the test object can have different distances from different nanowires, thereby enhancing the signal of the test object particles and making it applicable to test object particles of various sizes. In the fabrication method of the signal enhancement structure of the embodiments of the present invention, since these nanowires are repeatedly sprayed onto the surface with solvent, the particles of the test object can have different distances from different nanowires, thereby enhancing the signal of the test object particles and making it applicable to test object particles of various sizes. In the signal enhancement structure and signal enhancement measurement method of the embodiments of the present invention, since the thickness of the film layer falls within the range of 350 nanometers to 550 nanometers, the signal enhancement is more significant. This invention provides a structure and method for enhancing signals, which can be used simultaneously to enhance both surface-enhanced Raman scattering (SERS) and metal-enhanced fluorescence (MEF), thereby addressing the shortcomings of traditional detection methods that rely on Raman or fluorescence signals. Surface-enhanced Raman scattering (SERS) is a technique that enhances Raman scattering sensitivity by adsorbing particles or plasmas onto nanoscale rough metal surfaces. It can increase the Raman signal intensity by several orders of magnitude. However, factors such as different metal materials, the shape and size of surface particles, the amount of adsorbed object and the distance can all affect the effectiveness of surface-enhanced Raman scattering (SERS). Metal-enhanced fluorescence (MEF) primarily occurs when the fluorescent material and the metal are spaced a certain distance apart (e.g., 5–90 nm). The fluorescent material is influenced by the localized electric field of the metal nanoparticles. The excited electrons in the fluorescent material are amplified by this enhanced electromagnetic field, leading to more electrons jumping to the excited state and thus increasing its emission. The fluorescence enhancement effect is related to the material, shape, and distance of the metal nanoparticles. Its main mechanism involves the enhancement of the localized electric field near the fluorescent particles on the metal surface. When the incident light frequency interacts with the oscillation frequency of the metal's surface plasma (induced by incident light or fluorescence), a "localized surface plasmon resonance" (LSPR) occurs. This metal surface plasmon resonance is a crucial factor determining the optical properties of the metal nanoparticles. Figure 1 is a schematic diagram of the signal enhancement structure of the present invention, which can be used to detect coronaviruses. The present invention mainly uses a stacked nanostructure to enhance the signal of the detection spectrum. For example, it can enhance the effect of surface enhanced Raman scattering (SERS) or local surface plasma resonance (LSPR). It can even be applied to simultaneously or synchronously amplify the signals of SERS and LSPR, thereby increasing the accuracy of detection and the scope of application. Therefore, using the structure of the present invention, it is possible to detect a single virus. Figure 2A is a perspective view of the structure of the enhanced signal according to an embodiment of the present invention, and Figure 2B is a top view of the enhanced signal structure of Figure 2A. Referring to Figures 2A and 2B, the enhanced signal structure 100 of this embodiment is used to enhance the signal of a test object, such as a Raman signal or a photoluminescence signal. The enhanced signal structure 100 includes a plurality of nanowires 110 stacked on a first direction D1, a second direction D2, and a third direction D3, wherein these nanowires 110 extend in at least two directions. Particles of the test object 50 fall on these nanowires 110 or in the gaps G between these nanowires 110. In one embodiment, the particles of the test object 50 are, for example, molecules (with an outer diameter in the range of 1 to 5 nanometers), nanoparticles (with an outer diameter in the range of 50 to 100 nanometers), viruses (with an outer diameter of approximately 120 nanometers), bacteria (with an outer diameter of approximately 500 to 1000 nanometers), cells (with an outer diameter in the range of 10,000 to 2,000 nanometers), or any combination of the above particles. In this embodiment, the nanowires 110 have various angles along the first direction D1, the second direction D2, and the third direction D3. Figure 2B illustrates this with an example of various angles θ between the nanowires 110 and the third direction D3. For instance, some of these angles can be greater than 90 degrees, some can be less than 90 degrees, and some can be equal to 90 degrees. Furthermore, in this embodiment, the materials of these nanowires include gold, silver, platinum, other precious metals, or combinations thereof. In this embodiment, these nanowires 110 are stacked to form a film layer, with the third direction D3 being the thickness direction of the film layer. Both the first direction D1 and the second direction D2 are perpendicular to the third direction D3, and the particles of the test object 50 are at different distances from different nanowires 110 on the third direction D3. For example, in Figure 2A, the distance L1 between the particles of the test object 50 and nanowire 112 on the third direction D3 is different from the distance L2 between them and nanowire 114. In this embodiment, these nanowires 110 are straight. However, in another embodiment, as shown in Figure 2C, the nanowires 110e of the signal enhancement structure 100e can also be curved. Alternatively, in other embodiments, these nanowires can also be a combination of curved and straight shapes (e.g., a mixture of nanowires 110 in Figure 2A and nanowires 110e in Figure 2C). In this embodiment, these nanowires 110 are irregularly distributed. When the particles of the test object 50 are nanoparticles or viruses, the ratio of the width of the largest gap (i.e., the largest of the gaps G) to the smallest gap (i.e., the smallest of the gaps G) between these nanolines 110 falls within the range of 50 nanometers to 2000 nanometers. Regarding the mechanism of metal-enhanced fluorescence, a better fluorescence enhancement effect is achieved when the particles of the test object and the nanostructure are maintained at an appropriate distance, while the fluorescence enhancement effect is poor when the distance is too close or too far. In the signal enhancement structure 100 of this embodiment, since these nanowires 110 are stacked on the first direction D1, the second direction D2, and the third direction D3, that is, these nanowires 110 form a three-dimensional stacked structure, the particles of the test object 50 can have different distances from different nanowires 110. Therefore, the particles of the test object 50 can easily maintain an appropriate distance from a certain surrounding nanowire 110, so that the signal (e.g., fluorescence signal) of the particles of the test object 50 can be well enhanced, and it is applicable to particles of the test object 50 of various sizes. In addition, the numerical range of the ratio of the maximum gap to the minimum gap is also beneficial for the nanowires 110 to carry particles of the test object 50 of various sizes, thus making it suitable for measuring particles of the test object 50 of various sizes. Furthermore, the measurement in this embodiment does not require the binding of antibodies and antigens to capture analyte particles, thus more effectively reducing detection errors. Moreover, the analytes applicable to the enhanced signal structure 100 of this embodiment include non-biological molecules (such as pesticides, drugs, etc.) or biological organisms or their forms (such as bacteria, viruses, etc.). In other words, the types of analytes that can be measured are not limited; any analyte capable of generating Raman or photoluminescence signals can be measured. Figure 3 is a three-dimensional schematic diagram illustrating the surface plasmon resonance (SPR) generated by the enhanced signal structure of Figure 2A. Referring to Figures 2A and 3, when particles of the test object 50 (whether larger particles 50a or smaller particles 50b) fall on the surface plasmon region 111 of the nanowire 110, surface-enhanced Raman scattering can be achieved through surface plasmon resonance. Furthermore, for metal-enhanced fluorescence, when the distance between the particles of the test object 50 and the nanowire 110 is slightly greater than the thickness of the surface plasmon region 111 (for example, in Figure 3, the particles of the test object 50 are above the surface plasmon region 111 and maintain an appropriate distance from it), a good metal-enhanced fluorescence effect can be achieved. In addition, the region 113 near the intersection of nanowires 110 (i.e., the surface-enhanced Raman scattering hot spot, i.e., the plasmon distribution area) can achieve a good Raman signal enhancement effect through surface plasmon resonance. In other words, the signal enhancement structure 100 of this embodiment can simultaneously enhance both Raman and photoluminescence signals. Furthermore, as shown in FIG3, the signal enhancement structure 100 of this embodiment can achieve plasma distribution in the third direction D3 (thickness direction), thus achieving signal enhancement for particles of various sizes of the test object 50. Referring again to Figure 2A, in this embodiment, these nanowires 110 are stacked on the third direction D3 to form a film (i.e., the signal enhancement structure 100), and the thickness T1 of this film on the third direction D3 falls within the range of 350 nanometers to 550 nanometers. When the thickness T1 falls within the range of 350 nanometers to 550 nanometers, the aforementioned signal enhancement is more significant, and experimental data will be provided below. Figure 4 is a top view schematic diagram of the structure of the enhanced signal according to another embodiment of the present invention. Referring to Figure 4, the enhanced signal structure 100a of this embodiment is similar to the enhanced signal structure 100 of Figure 2B, but the difference is that the nanowires 110 of the enhanced signal structure 100a are regularly distributed, for example, arranged in various geometric shapes, but the present invention is not limited thereto. Figure 5 is a perspective view of the structure of the enhanced signal according to another embodiment of the present invention. Referring to Figure 5, the enhanced signal structure 100b of this embodiment is similar to the enhanced signal structure 100 of Figure 2A, and the differences between the two are described below. The enhanced signal structure 100b of this embodiment further includes a plurality of nanoparticles 120, and these nanowires 110 are stacked on these nanoparticles 120. The materials of these nanoparticles 120 are, for example, gold, silver, platinum, other precious metals, or combinations thereof. Figure 6 is a perspective view of the structure of the enhanced signal according to another embodiment of the present invention. Referring to Figure 6, the enhanced signal structure 100c of this embodiment is similar to the enhanced signal structure 100 of Figure 2A, and the differences between the two are as follows. The enhanced signal structure 100c of this embodiment further includes a plurality of nano-dendrimers 120c, and these nanowires 110 are stacked on these nano-dendrimers 120c. The materials of these nano-dendrimers 120c are, for example, gold, silver, platinum, other precious metals, or combinations thereof. Figure 7 is a perspective view of the structure of the enhanced signal according to another embodiment of the present invention. Referring to Figure 7, the enhanced signal structure 100d of this embodiment is similar to the enhanced signal structure 100 of Figure 2A, and the differences are as follows. The enhanced signal structure 100d of this embodiment further includes a nano-structure chip 130, and these nanolines 110 are disposed on the nano-structure chip 130. The surface of the nano-structure chip 130 may have nanostructures 132. In this embodiment, these nanostructures 132 facing the nanolines 110 are, for example, nano-recesses; however, in other embodiments, they may be nano-protrusions, or a combination of nano-recesses and nano-protrusions. The nano-structure chip 130 is, for example, a titanium dioxide chip, a titanium dioxide-platinum chip, or a gold nanochip. Figure 8 is a cross-sectional schematic diagram illustrating a method for fabricating an enhanced signal structure according to an embodiment of the present invention. Referring to Figures 2A and 8, the method for fabricating the enhanced signal structure of this embodiment can be used to fabricate the enhanced signal structure (e.g., enhanced signal structure 100) of the above embodiment. The method for fabricating the enhanced signal structure of this embodiment includes the following steps. First, as shown in Figure 8, a plurality of nanowires 110 dispersed in a solvent 60 are sprayed onto a surface 70 along with the solvent 60 to form a first nanowire layer 102. Next, after the solvent 60 in the first nanowire layer 102 evaporates, the plurality of nanowires 110 dispersed in the solvent 60 are sprayed onto the first nanowire layer 102 again along with the solvent 60 to form a second nanowire layer 104. After the solvent in the second nanowire layer 104 evaporates, the enhanced signal structure 100 as shown in Figure 2A is formed. In the general embodiment, after the solvent in the second nanowire layer 104 evaporates, multiple nanowires 110 dispersed in the solvent 60 can be sprayed onto the second nanowire layer 104 again along with the solvent 60 to form a third nanowire layer 106. After the solvent 60 in the third nanowire layer 106 evaporates, a thicker structure 100 for enhancing the signal can be formed. The number of nanowire layers is not limited to two or three layers as described above. In other embodiments, only one layer can be sprayed, or N layers can be sprayed, where N is a positive integer greater than or equal to 2. In another embodiment of the present invention, N is preferably in the range of 2 to 5. Surface 70 can be the surface of any object, or it can be the surface of the test object. When surface 70 is the surface of the test object, the aforementioned nanowire layer is sprayed onto surface 70. Here, the nanowire layer is sprayed as a single layer. In another embodiment of the present invention, the nanowire layer can be sprayed as multiple layers, preferably two layers. After the solvent 60 evaporates, a laser beam can be irradiated onto surface 70, and the converted beam formed by the conversion of the test object 50 particles on surface 70 by the laser beam can be detected to obtain the Raman signal or photoluminescence signal of the test object 50 particles. Thus, the signal enhancement structure 100 can enhance the Raman signal or photoluminescence signal of the test object 50 particles. When surface 70 is the surface of a carrier plate or any carrier (e.g., the surface of the nanostructure wafer 130 as shown in FIG. 7), the aforementioned nanowire layer is sprayed onto surface 70, and after the solvent 60 evaporates, the test object can be placed on surface 70, dropped onto surface 70, coated onto surface 70, or disposed on surface 70 in any suitable form. In another embodiment of the present invention, the number of nanowire layers sprayed is preferably 2 to 5. Then, surface 70 is irradiated with a laser beam as described above to obtain Raman or photoluminescence signals. Furthermore, in the fabrication of the signal enhancement structure 100b in Figure 5, multiple nanoparticles 120 can be mixed into solvent 60, and then sprayed onto surface 70 along with solvent 60. Similarly, in the fabrication of the signal enhancement structure 100c in Figure 6, multiple nanoflowers 120c can be mixed into solvent 60, and then sprayed onto surface 70 along with solvent 60. Since the signal enhancement structures of the above embodiments can simultaneously enhance Raman spectra and photoluminescence spectra (e.g., fluorescence spectra), if the analyte has both Raman and photoluminescence spectra, the signal enhancement structures of the above embodiments can be used to simultaneously measure the Raman and photoluminescence spectra of the analyte. The spectral measurement system for simultaneously measuring these two spectra is described below. Figure 9 is a schematic diagram of the optical path architecture of a spectral measurement system according to an embodiment of the present invention. Referring to Figure 9, the spectral measurement system 200 of this embodiment includes a first laser source 210, a second laser source 220, a beam splitter 230, a dichroic mirror 240, a first photodetector module 250, and a second photodetector module 260. The first laser source 210 emits a first peak wavelength laser beam 212, while the second laser source 220 emits a second peak wavelength laser beam 222, wherein the first peak wavelength of the first peak wavelength laser beam 212 is greater than the second peak wavelength of the second peak wavelength laser beam 222. The first peak wavelength laser beam 212 is used to measure the Raman spectrum of the particles of the test object 50, while the second peak wavelength laser beam 222 is used to measure the photoluminescence spectrum of the particles of the test object 50. The beam combining unit 290 combines the first peak wavelength laser beam 212 and the second peak wavelength laser beam 222 into a single laser output beam 215. In this embodiment, the beam combining unit 290 may include a dichroic mirror 292 and a dichroic mirror or reflector 294, which reflects the second peak wavelength laser beam 222 to the dichroic mirror 292. The dichroic mirror 292 is adapted to reflect the first peak wavelength laser beam 212 and to allow the second peak wavelength laser beam 222 to pass through, thus combining the first peak wavelength laser beam 212 and the second peak wavelength laser beam 222. The beam splitter 230 reflects the laser output beam 215 to the structure 100 of particles and enhanced signals of the analyte 50. In this embodiment, the spectral measurement system 200 may further include a mirror 270 to reflect the laser output beam 215 to the beam splitter 230. The particles of the analyte 50 convert the laser output beam 215 into a converted beam 51, wherein the converted beam 51 includes a Raman signal beam and a photoluminescence signal beam. A portion of the converted beam 51 penetrates the beam splitter 230 and is transmitted to the dichroic mirror 240. In this embodiment, the spectral measurement system 200 may further include a mirror 280 to reflect the converted beam 51 from the beam splitter 230 to the dichroic mirror 240. The dichroic mirror 240 reflects the portion of the converted beam 51 corresponding to the Raman signal, 53, to the first photodetector module 250, while allowing the portion of the converted beam 51 corresponding to the photoluminescence signal, 55, to pass through and be transmitted to the second photodetector module 260. In this way, the first photodetector module 250 can detect the Raman spectrum, and the second photodetector module 260 can detect the photoluminescence spectrum, thus enabling the spectral measurement system 200 to simultaneously detect both the Raman and photoluminescence spectra. Each of the first photodetector module 250 and the second photodetector module 260 may sequentially include a filter and a photodetector along the path of light transmission. In other embodiments, the first laser source 210 may emit a first peak wavelength laser beam 212, while the second laser source 220 may not emit a second peak wavelength laser beam 222, thus enabling the spectral measurement system 200 to measure the Raman spectrum without simultaneously measuring the photoluminescence spectrum. Alternatively, the first laser source 210 may not emit the first peak wavelength laser beam 212, while the second laser source 220 may emit a second peak wavelength laser beam 222, thus enabling the spectral measurement system 200 to measure the photoluminescence spectrum without simultaneously measuring the Raman spectrum. Figures 10A and 10B show the theoretical electric field values ​​and experimental results of surface-enhanced Raman scattering (SERS) of multilayer silver nanowires, respectively. Figure 10A was generated using light sources with wavelengths of 532 nm, 633 nm, and 785 nm. Figure 10B was generated using two test objects labeled "S" and "1A9" with light sources of 532 nm, 633 nm, and 785 nm. In Figure 10A, the electric field values ​​simulated by the finite integration technique (FIT) show optimization regardless of the incident irradiation wavelength, which is well supported by Figure 10B, which shows the experimental measurements of SERS of two-dimensional silver nanowire layers with different biomolecules under the same conditions. In Figure 10A, the vertical axis |E|... 2 The electromagnetic field is a theoretically calculated value. In Figure 10B, the vertical axis represents the photon count or the intensity of surface-enhanced Raman scattering. The intensity of the vertical axis refers to the photon count detected by the sensor (e.g., a charge-coupled device, CCD). As shown in Figures 10A and 10B, the number of nanowire layers that best enhances the signal is approximately 4. In the figures, "2L" represents 2 nanowire layers, "3L" represents 3 nanowire layers, and so on. If the diameter of the nanowire is approximately 100 nanometers, the thickness of the film formed by the nanowire that best enhances the signal falls within the range of 350 nanometers to 550 nanometers. Figure 11 is a structural schematic diagram illustrating one step of a method for measuring enhanced signals according to an embodiment of the present invention. Referring to Figures 9 and 11, the method for measuring enhanced signals in this embodiment includes the following steps. First, referring to Figure 11, a plurality of nanowires 110 dispersed in a solvent 60 are dropped or sprayed onto a surface of a test object 50 along with the solvent to form a film layer on the test object 50, wherein the thickness T1 of this film layer falls within the range of 350 nanometers to 550 nanometers. Next, referring to Figure 9, at least one of the Raman spectrum and photoluminescence spectrum of the test object 50 is measured, and its signal is enhanced by these nanowires 110 as described above. The test object 50 can be any kind of test object, such as fruit. Figure 12 is a structural schematic diagram illustrating one step of a method for measuring enhanced signals according to another embodiment of the present invention. Referring to Figures 9 and 12, the method for measuring enhanced signals in this embodiment includes the following steps. First, referring to Figure 12, a test sample 50 is mixed with a plurality of nanowires 110 dispersed in a solvent 60. Next, the test sample 50, along with the nanowires 110 dispersed in the solvent 60, is dropped or sprayed onto a substrate 140 to form a film layer on the substrate 140, wherein the thickness T1 of this film layer falls within the range of 350 nanometers to 550 nanometers. Then, referring to Figure 9, at least one of the Raman spectrum and photoluminescence spectrum of the test sample 50 is measured, the signal of which is enhanced by the nanowires 110. Figures 13A and 13B are schematic diagrams illustrating two steps of a signal enhancement measurement method according to another embodiment of the present invention. Referring to Figures 9, 13A, and 13B, the signal enhancement measurement method of this embodiment includes the following steps. First, referring to 13A, a plurality of nanowires 110 dispersed in a solvent 60 are dropped or sprayed onto a substrate 140 along with the solvent 60 to form a film layer on the substrate 140, wherein the thickness T1 of this film layer falls within the range of 350 nanometers to 550 nanometers. Next, referring to 13B, a test object 50 is dropped or sprayed onto this film layer. Then, at least one of the Raman spectrum and photoluminescence spectrum of the test object 50 is measured, and its signal is enhanced by these nanowires 110. In other embodiments, these nanowires 110 may be dropped or sprayed onto a plurality of nanoparticles 120, as illustrated in Figure 5. In Figures 11 to 13B, when measuring at least one of the Raman spectrum and photoluminescence spectrum of the analyte 50, the film layer can be cured or uncured; that is, the film layer may or may not contain solvent 60. In one embodiment, when forming this film layer, these nanowires 110 with solvent 60 (e.g., water) can be sprayed or dripped four times, with each spray or dripping being 20 microliters. In another embodiment, 60 microliters of these nanowires 110 with solvent 60 (e.g., water) can be sprayed or dripped, wherein these nanowires 110 have an optical density (OD) of 0.6. In summary, in the signal enhancement structure of the embodiments of the present invention, since these nanowires are stacked in the first, second, and third directions, the particles of the test object can have different distances from different nanowires, thereby enhancing the signal of the test object particles and making it applicable to test object particles of various sizes. In the fabrication method of the signal enhancement structure of the embodiments of the present invention, since these nanowires are repeatedly sprayed onto the surface with solvent, the particles of the test object can have different distances from different nanowires, thereby enhancing the signal of the test object particles and making it applicable to test object particles of various sizes. In the signal enhancement structure and signal enhancement measurement method of the embodiments of the present invention, since the thickness of the film layer falls within the range of 350 nanometers to 550 nanometers, the signal enhancement is more significant. 50: Analyte; 50a, 50b: Particles; 51: Converted beam; 53, 55: Partially converted beam; 60: Solvent; 70: Surface; 100, 100a, 100b, 100c, 100d, 100e: Signal enhancement structure; 102: First nanolayer; 104: Second nanolayer; 106: Third nanolayer; 110, 110e, 112, 114: Nanowires; 111: Surface plasma region; 113: Region near intersection; 120: Nanoparticles; 120c: Nanoflowers; 130: Nanostructure wafer; 132: Nanostructure; 14 0: Substrate; 200: Spectral Measurement System; 210: First Laser Source; 212: First Peak Wavelength Laser Beam; 215: Laser Output Beam; 220: Second Laser Source; 222: Second Peak Wavelength Laser Beam; 230: Beam Splitter; 240: Dichroic Mirror; 250: First Photodetector Module; 260: Second Photodetector Module; 270, 280: Reflector; 290: Beam Combining Unit; 292: Dichroic Mirror; 294: Dichroic Mirror or Reflector; D1: First Direction; D2: Second Direction; D3: Third Direction; G: Gap; L1, L2: Distance; T1: Thickness; θ: Angle Figure 1 is a schematic diagram of the enhanced signal structure of the present invention, which can be used to detect coronaviruses. Figure 2A is a perspective view of the enhanced signal structure of an embodiment of the present invention. Figure 2B is a top view of the enhanced signal structure of Figure 2A. Figure 2C is a perspective view of the enhanced signal structure of another embodiment of the present invention. Figure 3 is a perspective view illustrating the surface plasma resonance generated by the enhanced signal structure of Figure 2A. Figure 4 is a top view of the enhanced signal structure of another embodiment of the present invention. Figure 5 is a perspective view of the enhanced signal structure of yet another embodiment of the present invention. Figure 6 is a perspective view of the enhanced signal structure of yet another embodiment of the present invention. Figure 7 is a perspective view of the enhanced signal structure of another embodiment of the present invention. Figure 8 is a cross-sectional view illustrating the fabrication method of the enhanced signal structure of an embodiment of the present invention. Figure 9 is a schematic diagram of the optical path architecture of a spectral measurement system according to an embodiment of the present invention. Figures 10A and 10B respectively show the theoretical electric field value of multilayer nanostructured silver nanowires and the experimental results of surface-enhanced Raman scattering. Figure 11 is a structural schematic diagram showing one step of the enhanced signal measurement method according to an embodiment of the present invention. Figure 12 is a schematic diagram illustrating one step of a method for measuring enhanced signals according to another embodiment of the present invention. Figures 13A and 13B are schematic diagrams illustrating two steps of a method for measuring enhanced signals according to another embodiment of the present invention. 50: Test Item 100: Structure of Enhanced Signal 110, 112, 114: Nanowires D1: First Direction D2: Second Direction D3: Third direction G: Gap L1, L2: Distance T1: Thickness

Claims

1. A method for measuring enhanced signals, comprising: Multiple nanowires dispersed in a solvent are dropped or sprayed onto the surface of a test sample to form a film layer on the test sample, wherein the thickness of the film layer is in the range of 350 nanometers to 550 nanometers and the solvent is dropped or sprayed onto the surface multiple times; and at least one of the Raman spectrum and photoluminescence spectrum of the test sample is measured before the solvent evaporates, the signal of which is enhanced by the nanowires.

2. The signal enhancement measurement method as described in claim 1, wherein the nanowires in the film are stacked in a first direction, a second direction and a third direction, wherein the nanowires extend in at least two directions, and the nanowires have multiple different angles in the plane perpendicular to the first direction, the plane perpendicular to the second direction and the plane perpendicular to the third direction.

3. The method for measuring enhanced signals as described in claim 1, wherein the width ratio of the maximum to the minimum gap between the nanowires in the film layer falls within the range of 50 nanometers to 2000 nanometers.

4. The method for measuring enhanced signals as described in claim 1 further includes spraying a plurality of nanoparticles onto the test object, wherein the nanowires are stacked on the nanoparticles in the film layer.

5. The method for measuring the enhanced signal as described in claim 1, wherein the nanowires are irregularly distributed in the film layer.

6. The method for measuring enhanced signals as described in claim 1, wherein the nanowires in the film are curved, straight, or a combination thereof.

7. The method for measuring enhanced signals as described in claim 1, wherein the nanowires are made of gold, silver, platinum, or combinations thereof.

8. A method for measuring enhanced signals, comprising: A sample is mixed with multiple nanowires dispersed in a solvent; The analyte is dropped or sprayed onto a substrate along with nanowires dispersed in the solvent to form a film layer on the substrate, wherein the thickness of the film layer is in the range of 350 nm to 550 nm and the solvent is dropped or sprayed onto the substrate multiple times; and at least one of the Raman spectrum and photoluminescence spectrum of the analyte is measured before the solvent evaporates, the signal of which is enhanced by the nanowires.

9. The method for measuring enhanced signals as described in claim 8, wherein the width ratio of the maximum to the minimum gap between the nanowires in the film layer falls within the range of 50 nanometers to 2000 nanometers.

10. A method for measuring enhanced signals, comprising: Multiple nanowires dispersed in a solvent are dropped or sprayed onto a substrate along with the solvent to form a film layer on the substrate, wherein the thickness of the film layer is in the range of 350 nm to 550 nm and the solvent system is dropped or sprayed onto the substrate multiple times; an analyte is dropped or sprayed onto the film layer; and at least one of the Raman spectrum and photoluminescence spectrum of the analyte is measured before the solvent evaporates, the signal of which is enhanced by the nanowires.

11. The method for measuring enhanced signals as described in claim 10 further includes spraying a plurality of nanoparticles onto the substrate, wherein the nanowires are stacked on the nanoparticles in the film layer.

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