Enhanced graphene ultraviolet broadband light absorption structure and preparation method and application thereof

Abstract

The invention discloses an enhanced graphene ultraviolet broadband light absorption structure and a preparation method and application thereof, and relates to the technical field of photoelectric materials and nanotechnology. The structure is formed by arranging a plurality of periodic units, a single periodic unit structure sequentially comprises a metal substrate layer, a dielectric layer, a graphene layer and a metal array layer from bottom to top, the metal array layer is preferably made of silver, the dielectric layer is made of aluminum oxide, and the metal substrate layer is made of silver. The enhanced graphene ultraviolet broadband light absorption structure designed by the invention has relatively high absorption rate and relatively large bandwidth in the ultraviolet band, shows the characteristic of insensitivity to polarization and external environment refractive index, and has the advantages of small size, thin thickness, simple structure and easiness in integration and manufacturing; and the method has huge application value in high-performance ultraviolet photoelectric detectors, deep ultraviolet communication systems, ultraviolet spectrums and other advanced photon applications.

Description

Technical Field

[0001] The present invention relates to the field of optoelectronic materials and nanotechnology, and in particular to an enhanced graphene ultraviolet broadband light absorption structure and a preparation method and application thereof. Background Art

[0002] Graphene is a two-dimensional material consisting of a single layer of carbon atoms with a unique honeycomb lattice structure that was first isolated from graphite in 2004. Since then, graphene has attracted extensive research interest due to its excellent optical and electronic properties. These properties, including high carrier mobility, tunable conductivity, and high optical transparency, make graphene have great potential for application in optoelectronic devices. For example, graphene's high carrier mobility makes it excellent in high-speed electronic devices, while its tunable conductivity also makes it possible to manufacture tunable optoelectronic devices.

[0003] However, the intrinsic ultraviolet (UV) absorption rate of monolayer graphene is relatively low, which poses a significant obstacle to its application in photodetectors. Existing research results show that the UV absorption efficiency of graphene is highly dependent on the angle and polarization state of the incident light. Existing design structures usually have narrow absorption bandwidths and low absorption efficiencies, which limit the application of graphene in UV broadband photodetectors. In order to achieve higher responsiveness and optical gain in UV photodetectors, it is urgent to improve the absorption efficiency and bandwidth of monolayer graphene. In particular, in modern optoelectronic devices, a wide range of spectral responsiveness is the key to achieving high performance. However, relevant research on how to achieve broadband high absorption characteristics is still relatively scarce. To solve this problem, the development of new structures to optimize the UV absorption performance of graphene has become a current research hotspot. This may involve composites with other materials, improved nanostructure design, or the use of advanced manufacturing technologies. Researchers are also exploring external control methods such as electric fields, light, and chemical doping to dynamically adjust the optical properties of graphene to achieve more efficient UV absorption. These efforts will not only help improve the application prospects of graphene in optoelectronic devices, but may also promote innovative applications of other two-dimensional materials in the field of optoelectronics.

[0004] In the prior art, the invention patent application with application number CN202310528586.8, "A photodetector with a semiconductor graphene nanoribbon / silicon heterojunction having an aluminum oxide interface layer", discloses a photodetector, and its structural schematic diagram shows that the photodetector structure includes, from bottom to top, an n-type material contact electrode layer, an n-type material layer, an aluminum oxide layer, a p-type material layer, and a p-type material contact electrode layer. Among them, the material of the n-type material is Si; the material of the p-type material layer is a semiconductor graphene nanoribbon; the material of the p-type material contact electrode layer is one or more of nickel, chromium, gold, palladium, platinum, and silver; the material of the n-type material contact electrode layer is one or more of titanium, aluminum, copper, and indium. The preparation method of the structure is as follows: (1) using n-type Si as the n-type material layer and the substrate, depositing an aluminum oxide layer on the upper surface thereof to obtain a Si / Al2O3 sample; (2) coating the Si / Al2O3 sample with a semiconductor graphene nanoribbon suspension, and obtaining the p-type semiconductor graphene nanoribbon layer after the semiconductor graphene nanoribbon suspension is naturally air-dried to obtain a Si / Al2O3 / graphene nanoribbon sample; (3) annealing the Si / Al2O3 / graphene nanoribbon sample in an inert gas atmosphere; (4) depositing a p-type material contact electrode layer on the Si / Al2O3 / graphene nanoribbon sample after the treatment in step (3), and depositing an n-type material contact electrode layer on the back of the Si / Al2O3 / graphene nanoribbon sample. The application forms a heterojunction photodetector with graphene nanoribbons and a silicon substrate, and effectively suppresses dark current by inserting a thin aluminum oxide layer at the heterojunction interface, thereby producing a high-sensitivity photodetector that can achieve rapid light response. The photodetector has a simple process and low cost, but still has the following disadvantages: the application only provides a photodetector with a fast light response speed, and its specific absorption bandwidth and absorption efficiency are unknown.

[0005] In view of this, it is necessary to develop an enhanced graphene ultraviolet broadband light absorption structure to solve the above problems. Summary of the invention

[0006] The object of the present invention is to provide an enhanced graphene ultraviolet broadband light absorption structure.

[0007] Another object of the present invention is to provide a method for preparing the above-mentioned enhanced graphene ultraviolet broadband light absorption structure.

[0008] Another object of the present invention is to provide application of the above-mentioned enhanced graphene ultraviolet broadband light absorption structure in ultraviolet detection.

[0009] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0010] The enhanced graphene ultraviolet broadband light absorption structure of the present invention is composed of a plurality of periodic unit structures, wherein a single periodic unit is a metal base layer, a dielectric layer, a graphene layer and a metal array layer from bottom to top, wherein the material of the metal base layer is silver, the material of the dielectric layer is aluminum oxide, and the metal array layer is a square metal block composed of any one of silver, aluminum, copper, palladium and gold.

[0011] Preferably, the material of the metal array layer of the enhanced graphene ultraviolet broadband light absorption structure of the present invention is a square silver block with a thickness of 5 to 25 nm and a width of 155 to 175 nm.

[0012] Further preferably, the thickness of the square silver block of the metal array layer of the enhanced graphene ultraviolet broadband light absorption structure of the present invention is 10 nm and the width is 165 nm.

[0013] Preferably, the thickness of the dielectric layer of the enhanced graphene ultraviolet broadband light absorption structure of the present invention is 25 to 45 nm.

[0014] Further preferably, the thickness of the dielectric layer of the enhanced graphene ultraviolet broadband light absorption structure of the present invention is 35 nm.

[0015] Preferably, the thickness of the metal base layer of the enhanced graphene ultraviolet broadband light absorption structure of the present invention is 100 nm.

[0016] Preferably, a single periodic unit of the enhanced graphene ultraviolet broadband light absorption structure of the present invention is axisymmetric about the longitudinal and transverse centers, and the length and width are both 185 nm.

[0017] The method for preparing the enhanced graphene ultraviolet broadband light absorption structure of the present invention comprises the following steps:

[0018] S1: A layer of aluminum oxide was deposited on the silver substrate by electron beam evaporation;

[0019] S2: growing graphene on copper foil using chemical vapor deposition;

[0020] The specific process of growing graphene on copper foil by chemical vapor deposition is as follows:

[0021] (1) Copper foil cleaning: The copper foil was ultrasonically cleaned in an ethanol solution for 10 min to remove surface oil and impurities, then rinsed with deionized water several times and dried.

[0022] (2) High temperature annealing: In the CVD system, the copper foil is placed in the reaction chamber and hydrogen (H2) is introduced as a protective atmosphere. The temperature is raised to 1000°C and maintained for 30 minutes to remove the oxide layer on the copper surface and improve the grain quality.

[0023] (3) Graphene growth: methane (CH4) is introduced as the carbon source gas, and hydrogen is introduced as the protective atmosphere. The flow ratio of CH4 to H2 is controlled (e.g., 5:100) and the temperature is maintained at about 1000°C. The growth time is usually 10–30 minutes. Cooling, turning off the CH4 gas, retaining the hydrogen flow, and quickly cooling the copper foil to room temperature to avoid multilayer graphene growth.

[0024] S3: transferring the single-layer graphene grown in step S2 to the aluminum oxide layer in step S1;

[0025] The specific process of transferring graphene to the aluminum oxide layer is as follows:

[0026] (1) Coating the support layer: Spin-coat a layer of polymethyl methacrylate (PMMA) on the graphene surface as a support layer, and repeat the coating after drying to ensure strength.

[0027] (2) Removing copper foil: Immerse the copper foil in a nitric acid solution or an ammonium persulfate solution (usually 0.1-0.2 M) to chemically etch away the copper foil, leaving behind a single-layer graphene film supported by PMMA.

[0028] (3) Residue cleaning: Use deionized water to rinse the residual copper ions, and the graphene membrane remains in a floating state.

[0029] (4) Transfer to an alumina substrate: Immerse the alumina substrate in water, slowly transfer the PMMA / graphene film to the substrate surface, adjust the position, take it out and dry it.

[0030] (5) Removal of the support layer: Use acetone to dissolve the PMMA support layer and obtain a complete single-layer graphene film after drying.

[0031] (6) Post-treatment: If necessary, annealing treatment (e.g., 200-300°C in a hydrogen / argon atmosphere) can be performed to further remove residual organic matter and improve the quality of graphene.

[0032] S4: Fabrication of periodic square silver plates using focused ion beam lithography.

[0033] Preferably, in the method for preparing the enhanced graphene ultraviolet broadband light absorption structure of the present invention:

[0034] The operating parameters of the electron beam evaporation in step S1 are: vacuum degree 5×10 -6 mbar, voltage 5 kV, electron beam current 100 mA, deposition rate 0.1 nm / s;

[0035] The operating parameters of the focused ion beam lithography technology in step S3 are: the ion source is Ga+, the vacuum degree is 1×10 - 6mbar, ion beam acceleration voltage 30 kV, ion beam current 40 pA.

[0036] The application of the enhanced graphene ultraviolet broadband light absorption structure described in the present invention in ultraviolet detection.

[0037] Beneficial effects of the present invention:

[0038] The present invention provides an enhanced graphene ultraviolet wide-band light absorption structure, and the optimal process parameters of the structure are determined through parameter investigation experiments: the metal array layer material is silver; the thickness h of the metal array layer silver block is 10nm, and the width W is 165nm; the thickness d of the dielectric layer is 35nm. The structure has a high absorptivity and a large bandwidth in the ultraviolet band. The light absorption structure prepared under the above optimal process parameters has a maximum absorptivity of 75% at a central wavelength of 272nm for graphene, and a half-peak width (FWHM) of up to 140nm, which can meet its application requirements in ultraviolet absorption. At the same time, the structure shows the characteristics of being insensitive to polarization and the refractive index of the external environment, and has the advantages of small size, thin thickness, simple structure, easy integration and production, and has great application value in high-performance ultraviolet photodetectors, deep ultraviolet communication systems, ultraviolet spectroscopy and other advanced photonic applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A schematic diagram of the three-dimensional structure of multiple periodic arrays of enhanced graphene ultraviolet broadband absorption structures;

[0040] Figure 2 A schematic diagram of the three-dimensional structure of a periodic unit of the enhanced graphene ultraviolet broadband absorption structure;

[0041] Figure 3 The influence of metal array layers of different materials on the ultraviolet absorption of graphene;

[0042] Figure 4 The effect of different thickness of silver blocks in metal array layer on the ultraviolet absorption of graphene;

[0043] Figure 5 The effect of silver block width of different metal array layers on graphene ultraviolet absorption;

[0044] Figure 6 The effect of different dielectric layer thicknesses on graphene ultraviolet absorption;

[0045] Figure 7 It is the absorption curve of the enhanced graphene ultraviolet broadband absorption structure under the incident of transverse electric field light (TE) and transverse magnetic field light (TM);

[0046] Figure 8 This is the effect of different external environment refractive index on graphene ultraviolet absorption. DETAILED DESCRIPTION

[0047] The technical solution of the present invention is described in detail below in conjunction with specific embodiments. The following embodiments are only used for explanation and illustration, and do not constitute a limitation on the technical solution of the present invention.

[0048] Example 1

[0049] The enhanced graphene ultraviolet broadband light absorption structure is composed of multiple periodic unit structures. The width and length of a single periodic unit are both 185nm. From bottom to top, it is a metal substrate layer, a dielectric layer, a graphene layer, and a metal array layer. Among them, the material of the metal substrate layer is silver with a thickness of 100nm; the material of the dielectric layer is aluminum oxide with a thickness of 35nm; the metal array layer is a square silver block with a thickness of 10nm and a width of 165nm.

[0050] Example 2

[0051] The enhanced graphene ultraviolet broadband light absorption structure is composed of multiple periodic unit structures. The width and length of a single periodic unit are both 185nm. From bottom to top, it is a metal substrate layer, a dielectric layer, a graphene layer, and a metal array layer. Among them, the material of the metal substrate layer is silver with a thickness of 100nm; the material of the dielectric layer is aluminum oxide with a thickness of 35nm; the metal array layer is a square silver block with a thickness of 10nm and a width of 165nm.

[0052] Example 3

[0053] The enhanced graphene ultraviolet broadband light absorption structure is composed of multiple periodic unit structures. The width and length of a single periodic unit are both 185nm. From bottom to top, it is a metal substrate layer, a dielectric layer, a graphene layer, and a metal array layer. Among them, the material of the metal substrate layer is silver with a thickness of 100nm; the material of the dielectric layer is aluminum oxide with a thickness of 25nm; the metal array layer is a square aluminum block with a thickness of 5nm and a width of 155nm.

[0054] Example 4

[0055] The enhanced graphene ultraviolet broadband light absorption structure is composed of multiple periodic unit structures. The width and length of a single periodic unit are both 185nm. From bottom to top, it is a metal substrate layer, a dielectric layer, a graphene layer, and a metal array layer. Among them, the material of the metal substrate layer is silver with a thickness of 100nm; the material of the dielectric layer is aluminum oxide with a thickness of 45nm; the metal array layer is a square silver block with a thickness of 25nm and a width of 175nm.

[0056] Example 5

[0057] The preparation method of the enhanced graphene ultraviolet broadband light absorption structure comprises the following steps:

[0058] S1: By electron beam evaporation (operating parameters: vacuum degree 5×10 -6 mbar, voltage 5kV, electron beam current 100mA, deposition rate 0.1nm / s) to plate a layer of aluminum oxide on a silver substrate;

[0059] S2: growing graphene on copper foil using chemical vapor deposition;

[0060] S3: transferring the single-layer graphene grown in step S2 to the aluminum oxide layer in step S1;

[0061] S4: Focused ion beam lithography (operating parameters: ion source is Ga+, vacuum degree is 1×10 -6 mbar, ion beam acceleration voltage 30 kV, ion beam current 40 pA) to manufacture periodic square silver plates.

[0062] Example 6

[0063] The enhanced graphene ultraviolet broadband light absorption structure provided by the present invention is used for the preparation of a photoelectric detector, and then for ultraviolet detection.

[0064] In order to further verify the reliability of the present invention and screen out the best solution, the inventor conducted a series of experiments, as follows:

[0065] 1. Preparation of enhanced graphene ultraviolet broadband light absorption structure

[0066] This study designed an enhanced graphene ultraviolet broadband light absorption structure, which can achieve a broadband high absorption spectrum of graphene by applying the excitation of electric dipole resonance and local surface plasmon effect technology in the ultraviolet region, so as to meet the application requirements in the ultraviolet region. The structure includes a metal substrate layer, a dielectric layer, a graphene layer, and a metal array layer. The light source is set to be plane light incident vertically along the negative direction of the Z axis. The structure is as follows Figure 1-2 As shown. Among them, Figure 1 A schematic diagram of a three-dimensional structure of multiple periodic arrays of an enhanced graphene ultraviolet broadband absorption structure, wherein 1 is a metal array layer, 2 is a graphene layer, 3 is a dielectric layer, and 4 is a metal substrate layer; Figure 2 Schematic diagram of the three-dimensional structure of a periodic unit of the enhanced graphene ultraviolet wide-band absorption structure, where W1 / W2 is the width of the silver block in the metal array layer, h is the thickness of the silver block in the metal array layer, d is the thickness of the dielectric layer, H is the thickness of the metal substrate layer, and P1 / P2 is the width of a periodic unit.

[0067] The material of the metal substrate layer is preferably silver, and the dielectric constant of silver is given by the Drudea model:

[0068]

[0069] where ε ∞ is the metal dielectric constant at infinite frequency; ω is the angular frequency; ω p is the plasma frequency, ω p =1.37×10 16 s -1 ; γ is the collision frequency, γ = 8.5 × 10 13 s -1 The dielectric layer is made of aluminum oxide, whose refractive index is 1.6, and the graphene of the graphene layer is grown by chemical vapor deposition (CVD).

[0070] The enhanced graphene ultraviolet broadband light absorption structure designed in this study can be prepared by the following steps: First, electron beam evaporation (Auto306, Hind High Vacuum Company, operating parameters: vacuum degree 5×10 -6 mbar, voltage 5kV, electron beam current 100mA, deposition rate 0.1nm / s) to coat a layer of Al2O3 on the silver substrate. Then, a single layer of graphene grown on copper foil by CVD was transferred to the Al2O3 layer. Finally, focused ion beam (FIB) lithography was used to fabricate periodic square silver plates. The commonly used FIB settings were: Helios Nanolab 600i (FEI Company), operating parameters: ion source, Ga+; vacuum degree 1×10 -6 mbar; ion beam accelerating voltage 30 kV; ion beam current 40 pA.

[0071] 2. Process parameter optimization

[0072] 2.1 Effects of different metal array layers on graphene UV absorption

[0073] In order to study the absorption enhancement effect of graphene in the ultraviolet (UV) band, we analyzed the influence of different metal array structures on graphene absorption. Figure 3 As shown. Figure 3It can be seen that the absorption spectrum of graphene in the ultraviolet band shows significant differences due to the different types of metals used, because the dielectric function and plasma frequency of each metal are different, which will significantly change the localized surface plasmon effect and electric dipole resonance effect of the proposed structure. Among the metals studied, silver (Ag) shows the highest absorption peak, exceeding 0.7, highlighting its excellent ability to significantly enhance the ultraviolet absorption of graphene through efficient coupling with graphene. Aluminum (Al) also shows high absorption performance, with an absorption value close to 0.45 in the wavelength range of 200nm to 300nm. In contrast, the absorption curves of gold (Au), copper (Cu) and palladium (Pd) are relatively flat, with lower absorption values, showing stable but weak absorption characteristics. Silver is particularly suitable for enhancing the absorption performance of graphene in the ultraviolet band due to its strong localized surface plasmon resonance and electric dipole resonance effects. Therefore, metallic silver is selected as the material of the metal array layer.

[0074] 2.2 Effect of different thickness of silver blocks in metal array layer on graphene UV absorption

[0075] Silver is used as the metal array layer material, and the effect of the light absorption structure on graphene absorption is investigated when the thickness of the silver block is 5nm, 10nm, 15nm, 20nm, and 25nm. The results are as follows Figure 4 As shown. Figure 4 It can be seen that when the silver block thickness h changes from 5 to 25 nm, as h increases, the graphene absorption efficiency increases first and then decreases. When the silver block thickness h is 10 nm, the graphene absorption efficiency reaches the maximum value. Therefore, 10 nm is selected as the optimal parameter for the silver block thickness of the metal array layer.

[0076] 2.3 Effect of different silver block widths in metal array layers on graphene UV absorption

[0077] Silver was used as the metal array layer material, the thickness of the silver block was fixed at 10nm, and the effect of the light absorption structure on the graphene absorption was investigated when the width of the square silver block was 155nm, 160nm, 165nm, 170nm, and 175nm. The results are as follows: Figure 5 As shown. Figure 5 It can be seen that when the silver block width W changes from 155nm to 175nm, as W increases, the graphene absorption efficiency shows a trend of first increasing and then decreasing. When the silver block width is 165nm, the graphene absorption efficiency reaches the maximum value. Therefore, 165nm is selected as the optimal parameter for the silver block width of the metal array layer.

[0078] 2.4 Effect of different dielectric layer thickness on graphene UV absorption

[0079] Silver is used as the metal array layer, the thickness of the silver block is fixed at 10nm, the width of the silver block is 165nm, and the effect of the light absorption structure on the absorption of graphene is investigated when the thickness of the aluminum oxide dielectric layer is 25nm, 30nm, 35nm, 40nm, and 45nm. The results are as follows Figure 6 As shown. The change in the thickness of the dielectric layer will change the electric field distribution, affect the coupling between graphene and light, and thus affect the absorption of graphene. From the results, it can be seen that when the thickness of the aluminum oxide dielectric layer is 35nm, the absorption rate of graphene in the structure at the central wavelength of 272nm is the highest, which is 75%, and the half-maximum width (FWHM) is as high as 140nm. Therefore, 35nm is selected as the optimal parameter for the thickness of the dielectric layer.

[0080] 3. Process effect verification

[0081] 3.1 Effects of different polarization changes on graphene absorption

[0082] The effect of the polarization change of incident light from TE wave to TM wave on graphene absorption was investigated. The results are as follows: Figure 7 As shown. It can be seen from the results that the change in polarization of the incident light from TE wave to TM wave has no significant effect on the absorption spectrum. This can be attributed to the rotational symmetry of the structure, which makes the absorption of graphene insensitive to polarization. Therefore, the enhanced graphene ultraviolet broadband absorption structure proposed in this study has plan-independent characteristics.

[0083] 3.2 Effect of different external environment refractive index on graphene absorption

[0084] The effects of the light absorption structure on graphene absorption when the refractive index of the external environment increases from 1.0 to 1.5 were investigated. The results are as follows: Figure 8 As shown in the results, it can be seen that with the change of the refractive index n, although the absorptivity of graphene drops from a maximum of 75% to 65%, it can still maintain high absorption and the bandwidth remains unchanged.

[0085] 4. Analysis and discussion

[0086] In summary, this study provides an enhanced graphene ultraviolet broadband light absorption structure, and through parameter investigation experiments, the optimal process parameters of the structure are determined as follows: the metal array layer material is silver; the thickness h of the metal array layer silver block is 10nm, the width W is 165nm; the thickness d of the dielectric layer is 35nm. The above structure has a high absorptivity and a large bandwidth in the ultraviolet band. The light absorption structure prepared under the above optimal process parameters has a maximum absorptivity of 75% at a central wavelength of 272nm, and a half-maximum width (FWHM) of up to 140nm. At the same time, the device shows the characteristics of being insensitive to polarization and the refractive index of the external environment, and has the advantages of small size, thin thickness, simple structure, easy integration and manufacturing. It has great application value in high-performance ultraviolet photodetectors, deep ultraviolet communication systems, ultraviolet spectroscopy and other advanced photonic applications.

[0087] Although the present invention has been described in detail above by means of general description, specific implementation methods and experiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. An enhanced graphene ultraviolet broadband light absorption structure, characterized in that: The structure is composed of multiple periodic unit structures. A single periodic unit is a metal base layer, a dielectric layer, a graphene layer and a metal array layer from bottom to top. The material of the metal base layer is silver, the material of the dielectric layer is aluminum oxide, and the metal array layer is a square metal block composed of any one of silver, aluminum, copper, palladium and gold.

2. The enhanced graphene ultraviolet broadband light absorption structure according to claim 1, characterized in that: The material of the metal array layer is a square silver block with a thickness of 5 to 25 nm and a width of 155 to 175 nm.

3. The enhanced graphene ultraviolet broadband light absorption structure according to claim 2, characterized in that: The thickness of the square silver block is 10 nm and the width is 165 nm.

4. The enhanced graphene ultraviolet broadband light absorption structure according to claim 1, characterized in that: The thickness of the dielectric layer is 25-45 nm.

5. The enhanced graphene ultraviolet broadband light absorption structure according to claim 4, characterized in that: The thickness of the dielectric layer is 35 nm.

6. The enhanced graphene ultraviolet broadband light absorption structure according to claim 1, characterized in that: The thickness of the metal base layer is 100 nm.

7. The enhanced graphene ultraviolet broadband light absorption structure according to claim 1, characterized in that: The single periodic unit is axisymmetric about the longitudinal and lateral centers, and the length and width are both 185 nm.

8. The method for preparing the enhanced graphene ultraviolet broadband light absorption structure according to claim 1, characterized in that: Here are the steps: S1: A layer of aluminum oxide was deposited on the silver substrate by electron beam evaporation; S2: growing graphene on copper foil using chemical vapor deposition; S3: transferring the single-layer graphene grown in step S2 to the aluminum oxide layer in step S1; S4: Fabrication of periodic square silver plates using focused ion beam lithography.

9. The method for preparing the enhanced graphene ultraviolet broadband light absorption structure according to claim 8, characterized in that: The operating parameters of the electron beam evaporation in step S1 are: vacuum degree 5×10 -6 mbar, voltage 5 kV, electron beam current 100 mA, deposition rate 0.1 nm / s; The operating parameters of the focused ion beam lithography technology in step S3 are: the ion source is Ga+, the vacuum degree is 1×10 -6 mbar, ion beam acceleration voltage 30 kV, ion beam current 40 pA.

10. Application of the enhanced graphene ultraviolet broadband light absorption structure as claimed in claim 1 in ultraviolet detection.

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