Composite plasmonic structures fabricated by improved multiple heat treatment method and manufacturing method thereof

Abstract

The present invention relates to a composite plasmonic structure fabricated by an improved multi-heat treatment method and a method for manufacturing the same. More specifically, the invention relates to a composite plasmonic structure and a method for manufacturing it that allows for precise control of the size and density of gold nanoparticles by repeating a deposition-heat treatment cycle. This process is carried out by repeating the process of depositing a gold thin film on a substrate and performing a heat treatment. Repeating this deposition-heat treatment cycle increases the number of gold nanoparticles, thereby increasing surface coverage and the number of hot spots. Importantly, it is possible to fabricate the structure in a form where small nanoparticles are arranged around large metal nanoparticles. A uniform particle distribution without fluctuation between the edges and the center of the substrate can be achieved at the 6-inch wafer level. This method provides a time- and cost-effective method for improving plasmonic properties by manipulating the density and distribution of plasmonic molecules over a large area without using lithography or chemical synthesis.

Description

Technology Field

[0001] The present invention relates to a composite plasmonic structure, and more specifically, to a method for manufacturing a composite plasmonic structure capable of controlling the size and density of plasmonic nanostructures through an improved multi-heat treatment method. Background Technology

[0003] The plasmonic properties of nanoscale metal structures, known as plasmonic molecules, are attracting significant attention due to unique optical characteristics resulting from the collective oscillation of free electrons within the metal known as plasmons. Particularly in materials science, this has given rise to new technologies that have brought innovation to diverse fields ranging from biology to physics through enhanced interactions between light and matter. These properties have been observed in various applications such as photovoltaics, fluorescence detection, and surface-enhanced Raman scattering. Plasmononic molecules have enabled unprecedented sensitivity and specificity in scientific fields such as biomedical diagnostics and environmental monitoring. Manipulating the size, shape, and composition of plasmonic molecules offers numerous opportunities for application across various fields.

[0004] The properties of plasmons are highly sensitive to geometric structures. For this reason, researchers have explored various approaches to control the size and density of plasmonic nanostructures, such as chemical synthesis, lithography, and dewetting, to fabricate plasmonic molecules. Nanoparticles synthesized in solution exhibit high reproducibility and homogeneity. However, aligning these nanoparticles requires chemical or other interactions with the substrate. Furthermore, lithography-based processes capable of drawing precise structures on substrates face challenges in low-cost, large-area fabrication.

[0005] The dewetting method can generate nanoparticles over a large area by heat-treating a thin metal film. The size and distribution of the nanoparticles can be controlled by the substrate surface roughness, film thickness, and heat treatment temperature and time. However, it is very difficult to simultaneously satisfy the size distribution, number, and average distance between nearest particles of self-assembled nanoparticles. Prior art literature

[0007] Republic of Korea Published Patent No. 10-2017-0008045 Republic of Korea Registered Patent No. 10-1393200 The problem to be solved

[0008] The present invention has been devised to solve the above-mentioned problems, and the objective of the present invention is to provide a composite plasmonic structure capable of precisely controlling the size and density of gold nanoparticles through an improved multi-heat treatment method.

[0009] The technical problems that the invention aims to solve are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art to which the invention belongs from the description below. means of solving the problem

[0011] To achieve the above objective, the present invention provides a method for manufacturing a composite plasmonic structure comprising: a first step of forming a dielectric layer by depositing a transparent dielectric material on a substrate; a second step of depositing a primary metal thin film on the dielectric layer; a third step of forming primary metal nanoparticles on the primary metal thin film through a heat treatment process; a fourth step of depositing a secondary metal thin film on the substrate on which the primary metal nanoparticles are formed; and a fifth step of forming secondary metal nanoparticles on the deposited secondary metal thin film through a heat treatment process.

[0012] The size and density of the primary metal nanoparticles or the secondary nanoparticles can be controlled by adjusting the thickness of the primary metal thin film or the secondary metal thin film.

[0013] The above substrate may be one or more selected from the group consisting of silicon, alumina, polymer, and glass.

[0014] The above transparent dielectric material is silicon dioxide (SiO2) and silicon nitride (SiN x ), hafnium oxide (HfO₂) x ) and aluminum oxide (AlO x It may be one or more selected from a group consisting of ).

[0015] The thickness of the dielectric layer may be 200 to 400 nm.

[0016] The primary metal thin film and the secondary metal thin film may be one or more selected from the group consisting of gold, silver, platinum, aluminum, iron, zinc, copper, tin, bronze, brass, and nickel.

[0017] The thickness of the primary metal thin film and the secondary metal thin film may be 5 to 20 nm.

[0018] The method of depositing the above primary metal thin film and the above secondary metal thin film can be performed by any one method selected from the group consisting of electron beam deposition, thermal deposition, and sputtering deposition.

[0019] The heat treatment process of the third and fifth steps above can be performed at 700 to 900 ℃ for 1 to 5 minutes.

[0020] In addition, the present invention provides a composite plasmonic structure characterized by comprising: a substrate; a dielectric layer deposited on the substrate; and metal nanoparticles formed on the dielectric layer.

[0021] The substrate may be one or more selected from the group consisting of silicon, alumina, polymer, and glass.

[0022] The above transparent dielectric material is silicon dioxide (SiO2) and silicon nitride (SiN x ), hafnium oxide (HfO₂) x ) and aluminum oxide (AlO x It may be one or more selected from a group consisting of ).

[0023] The thickness of the dielectric layer may be 200 to 400 nm.

[0024] The metal of the above metal nanoparticles may be one or more selected from the group consisting of gold, silver, platinum, aluminum, iron, zinc, copper, tin, bronze, brass, and nickel.

[0025] The above metal nanoparticles may be in a form where small nanoparticles are arranged around large metal nanoparticles.

[0026] The average particle size of the large metal nanoparticles may be 70 to 200 nm, and the average particle size of the small nanoparticles may be 20 to 100 nm. Effects of the invention

[0028] By means of the solution to the above problem, the present invention can provide a plasmonic structure exhibiting superior properties by forming a composite structure in which small particles form a nanogap around a plasmonic single structure.

[0029] According to the present invention, a plasmonic structure can be provided that can improve plasmonic properties by manipulating the density and distribution of plasmonic molecules over a large area without using lithography or chemical synthesis.

[0031] The effects of the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art from the description in the claims. Brief explanation of the drawing

[0033] Figure 1 is a schematic diagram showing two dewetting processes. Figure 2 is an SEM image of gold nanoparticles immediately after (a) the first and (b) the second dewetting. Figure 3 shows SEM images of gold nanoparticles after de-wetting gold thin films with thicknesses of (a) 8 nm, (b) 10 nm, (c) 12 nm, and (d) 14 nm, (e) average particle size and (f) gold nanoparticle particle size distribution and coverage according to thin film thickness. Figure 4 shows the size distribution and planar and inclined plane SEM images of double dewetting gold nanoparticles with 8, 10, 12, and 14 nm films additionally deposited on a 10 nm gold single dewetting substrate. FIG. 5 shows (a) dark-field scattering spectra of primary and secondary dewetting gold nanoparticle substrates, (b) a 100 nm diameter particle with a bottom facet of 20%, (c) electric field distribution in a 5 nm spaced dimer formed by a 100 nm diameter facet particle, (d) electric field distribution in a gap composed of one 100 nm diameter particle and one 30 nm diameter particle, (e) electric field distribution in a gap composed of one 100 nm diameter particle and two 30 nm diameter particles, and (f) electric field distribution in a gap composed of one 100 nm diameter particle and three 30 nm diameter particles. Figure 6 shows (a) the SERS spectrum of benzenethiol measured for each substrate, (b) the SERS intensity of the 1072 cm⁻¹ peak (black square) of benzenethiol and 13 μm 2 (c) number of hotspots (spread less than 10 nm) in the region (red circle), Raman mapping data of a 4 cm x 4 cm large-area substrate dewetted twice with an additional 8 nm deposition at 1 mm intervals, and (d) SERS intensity histogram obtained from Raman mapping. Specific details for implementing the invention

[0034] The terms used in this invention have been selected based on currently widely used general terms, taking into account their functions within the invention; however, these terms may vary depending on the intent of those skilled in the art, case law, the emergence of new technologies, etc. Additionally, in specific cases, terms have been arbitrarily selected by the applicant, and in such cases, their meanings will be described in detail in the relevant description of the invention. Therefore, the terms used in this invention should be defined not merely by their names, but based on their meanings and the overall content of the invention.

[0035] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0036] When a part of a specification is described as “comprising” a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0037] Embodiments of the present invention are described below with reference to the attached drawings so that those skilled in the art can easily implement them. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0039] The present invention will be described in detail below.

[0041] The present invention provides a method for manufacturing a composite plasmonic structure comprising: a first step of forming a dielectric layer by depositing a transparent dielectric material on a substrate; a second step of depositing a primary metal thin film on the dielectric layer; a third step of forming primary metal nanoparticles on the primary metal thin film through a heat treatment process; a fourth step of depositing a secondary metal thin film on the substrate on which the primary metal nanoparticles are formed; and a fifth step of forming secondary metal nanoparticles on the deposited secondary metal thin film through a heat treatment process.

[0042] The size and density of the primary metal nanoparticles or the secondary nanoparticles can be controlled by adjusting the thickness of the primary metal thin film or the secondary metal thin film.

[0043] Through the above heat treatment process, a dewetting phenomenon can be induced, and the above primary and secondary metal nanoparticles can be formed.

[0044] The substrate may be one or more selected from the group consisting of silicon, alumina, polymers, and glass. More preferably, it may be a silicon substrate, but is not limited thereto.

[0045] The above transparent dielectric material is silicon dioxide (SiO2) and silicon nitride (SiN x ), hafnium oxide (HfO₂) x ) and aluminum oxide (AlO x It may be one or more selected from a group consisting of ).

[0046] The method of depositing the transparent dielectric material on the above substrate may be a plasma-enhanced chemical vapor deposition method, but is not limited thereto.

[0047] The thickness of the dielectric layer may be 200 to 400 nm, and more preferably 300 nm, but is not limited thereto.

[0048] The primary metal thin film and the secondary metal thin film may be one or more selected from the group consisting of gold, silver, platinum, aluminum, iron, zinc, copper, tin, bronze, brass, and nickel. More preferably, they may be gold, but are not limited thereto.

[0049] The thickness of the primary metal thin film and the secondary metal thin film may be 5 to 20 nm. By controlling the thickness of the metal thin film, the size of the metal nanoparticles can be precisely controlled. According to one embodiment of the present invention, it can be seen that there is a linear relationship between the thickness of the metal thin film and the size of the metal nanoparticles.

[0050] The method for depositing the primary metal thin film and the secondary metal thin film described above can be performed using any one method selected from the group consisting of electron beam deposition, thermal deposition, and sputtering deposition. More preferably, it may be an electron beam deposition method, but is not limited thereto.

[0051] The heat treatment process of the third and fifth steps above can be performed at 700 to 900 ℃ for 1 to 5 minutes. Preferably, it can be performed at 800 to 850 ℃ for 1 to 3 minutes, and more preferably at 820 ℃ for 2 minutes, but is not limited thereto.

[0052] According to one embodiment of the present invention, the coverage of the primary metal nanoparticles is 10 to 30%, indicating that the particles are well dispersed on the substrate, and the distribution of the primary metal nanoparticles shows a Gaussian pattern as can be seen in FIG. 3(f).

[0053] According to one embodiment of the present invention, it can be seen that the coverage of the secondary metal nanoparticles increases by 1.75 times compared to the primary metal nanoparticles. The distribution of the secondary metal nanoparticles exhibits two Gaussian distributions, which may be attributed to two types of particles, such as particles whose size has increased due to the additional deposition of the secondary metal thin film on the primary metal nanoparticles and particles composed only of the additionally deposited secondary metal thin film.

[0054] Through the above secondary metal thin film deposition and secondary heat treatment processes, a much larger amount of plasmon molecules can be obtained, and the distribution of metal nanoparticles can also be significantly adjusted.

[0055] In addition, the present invention provides a composite plasmonic structure characterized by comprising: a substrate; a dielectric layer deposited on the substrate; and metal nanoparticles formed on the dielectric layer.

[0056] The substrate may be one or more selected from the group consisting of silicon, alumina, polymers, and glass. More preferably, it may be a silicon substrate, but is not limited thereto.

[0057] The above transparent dielectric material is silicon dioxide (SiO2) and silicon nitride (SiN x ), hafnium oxide (HfO₂) x ) and aluminum oxide (AlO x It may be one or more selected from a group consisting of ).

[0058] The thickness of the dielectric layer may be 200 to 400 nm, and more preferably 300 nm, but is not limited thereto.

[0059] The metal of the above metal nanoparticles may be one or more selected from the group consisting of gold, silver, platinum, aluminum, iron, zinc, copper, tin, bronze, brass, and nickel. More preferably, it may be gold, but is not limited thereto.

[0060] The metal nanoparticles may be in a form where small nanoparticles are arranged around large metal nanoparticles. According to one embodiment of the present invention, a form in which small nanoparticles are arranged around large metal nanoparticles can be formed through two dewetting steps.

[0061] The average particle size of the large metal nanoparticles may be 70 to 200 nm, and the average particle size of the small nanoparticles may be 20 to 100 nm.

[0063] Hereinafter, the present invention will be described in detail with reference to examples to specifically explain the invention. However, the embodiments according to the present invention may be modified in various different forms, and the scope of the present invention is not to be interpreted as being limited to the embodiments described below. The embodiments of this specification are provided to more completely explain the present invention to those with average knowledge in the art.

[0065] <Example 1> Preparation of a substrate with secondary gold nanoparticles formed

[0066] A 6-inch Si wafer was coated with 300 nm of silicon dioxide (SiO2) using PECVD (TES TELIA 200) at a substrate temperature of 350°C. Subsequently, 10 nm of gold was deposited on the silicon dioxide layer using an electron beam deposition system (Korea Vacuum Tech, Gimpo, KVE-E2000L). Then, the substrate was heated to 820°C for 90 seconds using a rapid thermal annealing system (SNTEK, Suwon, RTP-5000) and maintained at this temperature for 2 minutes. After cooling, an additional 8 nm thick gold thin film was deposited using an electron beam evaporator. Heat treatment was then performed under the same conditions as before using the same heat treatment equipment.

[0068] <Example 2> Preparation of a substrate with secondary gold nanoparticles formed

[0069] It was manufactured in the same manner as in Example 1, but with an additional deposition of a 10 nm thick gold thin film.

[0071] <Example 3> Preparation of a substrate with secondary gold nanoparticles formed

[0072] It was manufactured in the same manner as in Example 1, but with an additional deposition of a 12 nm thick gold thin film.

[0074] <Example 4> Preparation of a substrate with secondary gold nanoparticles formed

[0075] It was manufactured in the same manner as in Example 1, but with an additional deposition of a 14 nm thick gold thin film.

[0077] <Comparative Example 1> Preparation of a substrate on which primary gold nanoparticles are formed

[0078] A 6-inch Si wafer was coated with 300 nm of silicon dioxide (SiO2) using PECVD (TES TELIA 200) at a substrate temperature of 350°C. Then, an 8 nm gold thin film was deposited on the silicon dioxide layer using an electron beam deposition system (Korea Vacuum Tech, Gimpo, KVE-E2000L). Next, the substrate was heated to 820°C for 90 seconds using a rapid thermal annealing system (SNTEK, Suwon, RTP-5000) and maintained at this temperature for 2 minutes.

[0080] <Comparative Example 2> Preparation of a substrate on which primary gold nanoparticles are formed

[0081] It was prepared in the same manner as Comparative Example 1, but by depositing a 10 nm thin film on a silicon dioxide layer.

[0083] <Comparative Example 3> Preparation of a substrate on which primary gold nanoparticles are formed

[0084] It was prepared in the same manner as Comparative Example 1, but by depositing a 12 nm thin film on a silicon dioxide layer.

[0086] <Comparative Example 4> Preparation of a substrate on which primary gold nanoparticles are formed

[0087] It was prepared in the same manner as Comparative Example 1, but by depositing a 14 nm thin film on a silicon dioxide layer.

[0089] <Experimental Example 1> SEM Analysis of Primary Gold Nanoparticles

[0090] Structure verification was performed using a field emission SEM (Hitachi, Tokyo, Japan, S-4800) with an acceleration voltage of 10 kV and an emission current of 10 uA.

[0091] SEM images of primary gold nanoparticles are shown in Figure 3.

[0092] The average diameter of the particles is approximately 13㎛. 2 It was measured in the area. As can be seen in Fig. 3(e), the average diameters of the samples deposited at 8 nm, 10 nm, 12 nm, and 14 nm are 43.7 nm, 74.3 nm, 105.6 nm, and 142.3 nm, respectively. This result demonstrates a linear relationship between particle size and thin film thickness. This indicates that particle size can be precisely controlled by adjusting the thickness of the thin film.

[0093] In addition, the particle coverage was found to be approximately 20% in all cases, indicating that the particles were well dispersed on the substrate. The particle distribution followed a Gaussian-like pattern, as can be seen in Figure 3(f). However, it was observed that the coverage remained similar across all particle sizes despite the increase in particle size. This suggests that the number of hot spots on the particle surface decreases as the particle size increases.

[0094] SEM analysis results demonstrate that the size of gold nanoparticles can be precisely controlled by adjusting the thickness of the thin film. However, the observation that coverage remains constant as particle size increases indicates that the number of particles per unit area decreases.

[0096] <Experimental Example 2> SEM Analysis and Particle Distribution Analysis of Secondary Gold Nanoparticles

[0097] A substrate on which primary gold nanoparticles were formed by depositing a 10 nm gold thin film was used as an initial bare particle substrate, and additional gold films of 8, 10, 12, and 14 nm were deposited on the substrate. After heat treatment at 820°C for 2 minutes, SEM images were examined as shown in Fig. 4.

[0098] In all cases, particle coverage increased to approximately 35%, indicating a 1.75-fold increase in coverage compared to the first dewetting process. However, the particle distribution differed from that of single-dewetting particles, which is close to a single Gaussian distribution. Instead, the distribution of particles dewetting twice appeared to resemble two Gaussian distributions, which appears to be due to two types of particles: particles that have grown in size due to the additional deposition of a gold film on previously formed particles, and particles composed solely of the newly deposited film.

[0099] To investigate the particle size distribution more accurately, two Gaussian curves were fitted to the data. As shown in Figure 4, the composite curve (black dash) showed a slight increase in average values ​​compared to the original particles, while the new Gaussian curve (green dash) showed a distinct increase in average values. In particular, during the second dewetting from 8 nm to 14 nm, the average values ​​of the black dash were 80.6 nm at 8 nm, 82.1 nm at 10 nm, 86.7 nm at 12 nm, and 91.7 nm at 14 nm. On the other hand, the average values ​​of the green dash were 32.5 nm at 8 nm, 34.1 nm at 10 nm, 102.4 nm at 12 nm, and 144 nm at 14 nm. These values ​​are similar to the average deposition thickness of each thin film thickness observed during the first deposition.

[0100] The Gaussian model used to verify the distribution of the second-order dewetting gold nanoparticles in Figure 4 is as follows.

[0101]

[0102] Here, A is the amplitude of the Gaussian curve, μ is the mean, and σ is the standard deviation.

[0103] The values ​​used for each fitting are shown in Table 1.

[0104] 8nm add. 10nm add. 12nm add. 14nm add. 1차 디웨팅 Black A 5100 6553 2215 1094 4855 μ 80.6 82.0 86.7 91.7 75.6 σ 25.9 25.1 19.1 19.9 38.5 Grean A 10950 3219 2785 3094 μ 32.5 34.0 102.4 144.2 σ 15.7 12.2 15.8 16.76

[0106] These results confirm that a much larger amount of plasmon molecules can be obtained by performing the dewetting process twice. This results in a 1.75-fold increase in substrate coverage, suggesting that not only can the number of particles per unit area be increased, but the particle size distribution can also be significantly adjusted as needed.

[0108] <Experimental Example 3> Dark-field scattering spectrum analysis and electric field distribution simulation

[0109] To confirm the plasmonic characteristics of the twice-dewetted particles, the dark-field scattering spectrum was first analyzed (Fig. 5(a)). Although the dark-field scattering peak of the bare particles was close to 570 nm, red-biased dark-field scattering was observed on all substrates, including those with additional deposition of 8 nm and 10 nm particles, which were much smaller. This suggests that even when smaller particles are dominant, the distance between particles is small enough to generate hot spots.

[0110] To investigate the characteristics of these hotspots, electric field distribution simulations were performed (Figs. 5(b)-(e)). The simulation model included a single gold nanosphere with a faceted bottom surface and a diameter of 100 nm (Fig. 5(b)). Additionally, two of these particles were arranged to form a dimer shape with a 5 nm gap (Fig. 5(c)). In this case, an electric field enhancement of several tens of times was observed at the point closest to the particle, which is consistent with previous reports.

[0111] To investigate the case of dewetting a relatively thin film, such as 8 nm, rather than a typical dimer state of the same size, a dimer composed of faceted particles with a diameter of 100 nm and particles with a diameter of 30 nm was identified. As a result, it was confirmed that a clear hotspot was formed, although slightly weaker compared to the 100 nm - 100 nm particles (Fig. 5(d)).

[0112] In addition, SEM images of additionally deposited 8 nm double-wet particles showed that several small particles were attached around a large particle. To understand this configuration, two small particles (Fig. 5(e)) and three small particles (Fig. 5(f)) were simulated around a large particle. In the case of triple, the intensity of electric field enhancement was nearly similar to that of small particles. However, in the case of quadruple, the enhancement intensity tended to decrease, indicating that plasmon properties may not be significantly improved if the number of particles is increased indiscriminately.

[0114] <Experimental Example 4> SERS Performance Evaluation

[0115] The improvement in plasmonic performance resulting from an increase in the number of hotspots can be verified by measuring whether SERS enhancement is effective. To investigate the enhanced plasmonic characteristics of structures fabricated via secondary dewetting compared to primary dewetting, benzenethiol material was coated onto a substrate, and SERS performance was evaluated (Fig. 6(a)). Raman spectra were obtained using a 633 nm laser with a 0.5 mW output and a 50x objective lens with an NA of 0.75. Compared to the structure dewetting primary, the 1072 cm⁻¹ of benzenethiol -1 The peak was found to be enhanced more than 30 times in the secondary dewetting particles.

[0116] 1072 cm⁻¹ of benzenethiol to compare Raman signals under secondary dewetting conditions -1The SERS intensity of the peak was plotted against the additionally deposited thickness (Fig. 6(b)). As the thickness of the additionally deposited thin film increased, the SERS signal gradually weakened, which is expected to be due to a decrease in the number of hotspots per laser spot. To verify this, 13 μm 2 The number of gaps with a gap size of less than 10 nm within the area was counted for each substrate (Fig. 6(b)). In the case of a single dewetting, there were 24 hotspots, and it is expected that the SERS enhancement is mostly due to the contribution of single particles rather than the enhancement caused by hotspots. However, in the case of a substrate with an additional 8 nm thin film dewetting, the number of hotspots in the same area was 678 and the number of gaps smaller than 5 nm was 90, indicating a much stronger enhancement effect. However, as the thickness of the additionally deposited thin film increased, the number of hotspots gradually decreased. When a 10 nm thin film was additionally deposited, there were 302 hotspots, 85 for 12 nm, and 68 for 14 nm. When a 14 nm thin film was additionally deposited, only 10 gaps smaller than 5 nm appeared, so it is expected that it will be difficult to observe a significant improvement.

[0117] To ensure substrate uniformity, Raman mapping was performed at 1mm intervals on a large area of ​​4cm x 4cm of a substrate dewetted with an additional 8nm thin film. To minimize errors caused by laser focusing, mapping was performed using a 10x objective lens with an NA of 0.25 at an intensity of 1mW (Fig. 6(c)). The average SERS intensity was 980.4 count / s with a deviation of approximately 21.4%, indicating that hotspots are distributed across the entire substrate.

[0118] As such, the double dewetting method demonstrated the effect of enhancing plasmonic properties by increasing the number of plasmon molecules over a wide area using a very simple method. As the number of plasmon molecules increases significantly through double dewetting, the number of hot spots also increases substantially, which is expected to be of direct assistance to actual plasmonics applications.

[0120] Specific embodiments of the present invention have been examined so far. Those skilled in the art will understand that the present invention may be embodied in modified forms without departing from the essential characteristics of the invention. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the present invention is defined by the claims, not by the foregoing description, and all variations within the scope of equivalents should be interpreted as being included in the present invention.

Claims

Claim 1 A method for manufacturing a composite plasmonic structure comprising: a first step of forming a dielectric layer by depositing a transparent dielectric material on a substrate; a second step of depositing a primary metal thin film on the dielectric layer; a third step of forming primary metal nanoparticles through a heat treatment process on the primary metal thin film; a fourth step of depositing a secondary metal thin film on the substrate on which the primary metal nanoparticles are formed; and a fifth step of forming secondary metal nanoparticles through a heat treatment process on the deposited secondary metal thin film, wherein the primary metal thin film and the secondary metal thin film are gold thin films, and the primary metal nanoparticles and secondary metal nanoparticles are in the form of large metal nanoparticles having a secondary metal thin film additionally deposited on the primary metal nanoparticles and small metal nanoparticles composed only of the additionally deposited secondary metal thin film, wherein the average particle size of the large metal nanoparticles is 70 to 200 nm and the average particle size of the small metal nanoparticles is 20 to 100 nm. Claim 2 A method for manufacturing a composite plasmonic structure according to claim 1, characterized by controlling the size and density of the primary metal nanoparticles or the secondary metal nanoparticles by adjusting the thickness of the primary metal thin film or the secondary metal thin film. Claim 3 A method for manufacturing a composite plasmonic structure according to claim 1, characterized in that the substrate is one or more selected from the group consisting of silicon, alumina, polymer, and glass. Claim 4 In claim 1, the transparent dielectric material is silicon dioxide (SiO2) and silicon nitride (SiN x ), hafnium oxide (HfO₂) x ) and aluminum oxide (AlO x A method for manufacturing a composite plasmonic structure characterized by having one or more selected from the group consisting of ). Claim 5 A method for manufacturing a composite plasmonic structure according to claim 1, characterized in that the thickness of the dielectric layer is 200 to 400 nm. Claim 6 delete Claim 7 A method for manufacturing a composite plasmonic structure according to claim 1, characterized in that the thickness of the primary metal thin film and the secondary metal thin film is 5 to 20 nm. Claim 8 A method for manufacturing a composite plasmonic structure according to claim 1, characterized in that the method of depositing the primary metal thin film and the secondary metal thin film is performed by any one method selected from the group consisting of electron beam deposition, thermal deposition, and sputtering deposition. Claim 9 A method for manufacturing a composite plasmonic structure according to claim 1, characterized in that the heat treatment process of the third step and the fifth step is performed at 700 to 900 ℃ for 1 to 5 minutes. Claim 10 A composite plasmonic structure comprising: a substrate; a dielectric layer deposited on the substrate; and metal nanoparticles formed on the dielectric layer, wherein the metal nanoparticles are gold nanoparticles, and the metal nanoparticles are in the form of large metal nanoparticles having a secondary metal thin film additionally deposited on primary metal nanoparticles and small metal nanoparticles composed only of the additionally deposited secondary metal thin film, wherein the average particle size of the large metal nanoparticles is 70 to 200 nm and the average particle size of the small metal nanoparticles is 20 to 100 nm. Claim 11 In claim 10, the composite plasmonic structure is characterized in that the substrate is one or more selected from the group consisting of silicon, alumina, polymers, and glass. Claim 12 In claim 10, the dielectric layer comprises a transparent dielectric material, and the transparent dielectric material is silicon dioxide (SiO2) or silicon nitride (SiN x ), hafnium oxide (HfO₂) x ) and aluminum oxide (AlO x A composite plasmonic structure characterized by being one or more selected from the group consisting of ). Claim 13 A composite plasmonic structure according to claim 10, characterized in that the thickness of the dielectric layer is 200 to 400 nm. Claim 14 delete Claim 15 delete Claim 16 delete

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