A metal spiral cantilever array structure and a thermal radiation regulation method

Abstract

The present application relates to a kind of based on metal spiral cantilever array structure and thermal radiation spectrum regulation method, belong to infrared optics, thermal radiation spectrum regulation technical field.The super surface of the present application proposes composite helical line metal structure design, by voltage, make structure deformation, can realize regulation and control to the infrared thermal radiation spectrum intensity and spectrum peak wavelength of structure.The present application is directly realized by voltage for the regulation and control mode of metal super surface, relative to other methods of regulation and control by temperature, thermal phase change, simple operation system is not involved Complex uncontrollable chemical reaction.The present application proposes the thermal radiation spectrum regulation method based on metal spiral cantilever array structure, compared with prior art, break through the problem that only adjust thermal radiation spectrum intensity or only small range adjust thermal radiation spectrum peak wavelength;Meanwhile, the compatible performance of the present application to a variety of materials solves the problem that other methods excessively depend on the characteristics of material itself.

Description

Technical Field

[0001] This invention relates to a metal spiral cantilever array structure and a method for controlling thermal radiation spectrum, belonging to the fields of infrared optics and thermal radiation spectrum control technology. Background Technology

[0002] The technology of modulating thermal radiation spectrum has important applications in solar energy utilization, energy conservation, radiative cooling, infrared stealth, and infrared imaging technology. For example, in solar energy utilization, the modulation of thermal radiation spectrum can improve photoelectric conversion efficiency. In radiative cooling, radiative cooling devices can generate a cooling effect by modulating the absorption and emission of visible and near-infrared bands, thereby achieving dynamic thermal management. In infrared stealth, the visibility of infrared cameras to targets can be affected by dynamically controlling the intensity and peak wavelength of thermal radiation spectrum on the surface of materials, thereby achieving infrared stealth and camouflage.

[0003] However, the spectral modulation capabilities of most current thermal radiation modulation schemes are not ideal. The spectral performance of the thermal radiation modulation devices used is not modulated after fabrication, or they cannot achieve multi-dimensional modulation of the thermal radiation spectrum, failing to dynamically adapt to real-time environmental changes in various application scenarios, thus reducing application performance. Most current thermal radiation spectral modulation methods only modulate the intensity of the thermal radiation spectrum, such as... Figure 1 (The left design achieves dynamic control of thermal radiation spectral intensity by modulating the spectral absorbance. The basic principle is to change the properties of the electrochromic materials tungsten trioxide and nickel oxide by applying voltage, thereby adjusting the spectral intensity.) Some thermal radiation spectral modulation methods can modulate the peak wavelength of the thermal radiation spectrum within a small range, but their performance is poor, such as... Figure 1 (This design is based on the use of phase change materials and the method of zero-differential thermal radiation (i.e., not changing with temperature within a certain temperature range) to change the peak wavelength of the thermal radiation spectrum.) Therefore, there is a lack of a flexible method or design for controlling the thermal radiation spectrum that can adjust both the intensity and the peak wavelength of the thermal radiation spectrum.

[0004] In existing technologies, a scheme to dynamically control the thermal radiation spectrum by changing material properties through voltage control involves stacking a metal thin film etched with a square array, vanadium oxide crystals, and titanium oxide crystals together. By applying voltage, the conductivity of vanadium oxide is altered, thus achieving dynamic intensity tuning of the thermal radiation spectrum (e.g., ...). Figure 1 right).

[0005] In general, the existing methods for dynamic spectral manipulation of thermal radiation rely on the intrinsic emission characteristics of specific materials. Therefore, the range of controllable peak wavelength and intensity of thermal radiation is small, the control methods are relatively limited, and the spectral dimensions controlled are also very simple. Summary of the Invention

[0006] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose a method for controlling thermal radiation spectrum based on a metal spiral cantilever array structure. Based on this metal spiral cantilever structure, not only can the spectral intensity be adjusted, but also the peak wavelength of the thermal radiation spectrum can be adjusted. Based on this property, a temperature control device with adjustable temperature can be made.

[0007] The technical solution of this invention is:

[0008] A metal spiral cantilever array structure is characterized by the following method for fabricating the metal spiral cantilever array structure:

[0009] Step 1: Deposit a chromium layer on the substrate, and then deposit a metal layer on the chromium layer; the substrate consists of two layers, with silicon dioxide as the upper layer and silicon as the lower layer;

[0010] Step 2: Etch a composite spiral structure pattern array on the sample obtained in Step 1, with the etching depth reaching the silicon substrate. The interior of each composite spiral structure pattern is a windmill spiral, and the exterior is an Archimedean spiral.

[0011] Step 3: Etch the silicon dioxide under the metal layer pattern to obtain a metal spiral cantilever array structure.

[0012] In step one, the thickness of the deposited chromium layer is 5-10 nm, and the thickness of the deposited metal layer is 60-100 nm.

[0013] The individual structural design pattern of the metal spiral cantilever array structure is a composite spiral, composed of windmill spirals internally and Archimedean spirals externally.

[0014] The windmill has three or four spiral lines;

[0015] When the windmill spiral has three lines, the angle in the parametric equation takes values ​​of 0.8-50°.

[0016] When the windmill has four spirals, the angles in the parametric equations range from 0.8 to 45°.

[0017] The Archimedes spiral can have three, four, five, or six strands;

[0018] When there are three Archimedes spirals, the angles in the parameterized equations range from 50 to 380°.

[0019] When there are four Archimedes spirals, the angles in the parameterized equations range from 100 to 380°.

[0020] When there are five Archimedes spirals, the angles in the parametric equations range from 150° to 380°.

[0021] When there are six Archimedes spirals, the angles in the parametric equations range from 200 to 380°.

[0022] The line width of the wind turbine spiral is 60-150nm;

[0023] The linewidth of the Archimedean spiral is 60-150 nm.

[0024] The period size of a single array is 3.25-5 μm.

[0025] In step two, the composite spiral structure pattern array is etched using focused ion beam etching technology or electron beam exposure and development technology.

[0026] In step three, hydrofluoric acid is used to etch the silicon dioxide beneath the aluminum layer.

[0027] The metal layer is made of aluminum, gold, molybdenum, copper, or magnesium.

[0028] When a voltage is applied to the upper and lower surfaces of the metal spiral cantilever array structure, the electrostatic attraction between the metal layer and the silicon drives the pattern of the metal spiral cantilever array structure to reciprocate and deform as the voltage increases or decreases.

[0029] The deformation of the pattern in the metal spiral cantilever array structure causes multi-dimensional changes in its thermal radiation spectrum, including variations in peak wavelength and intensity. Furthermore, this method is applicable to various metal types and structural patterns, meeting the material and temperature constraints required for different mid-infrared applications. Compared to other methods, this approach is simpler, has a wider range of applications, does not involve complex chemical reactions, and can achieve multi-dimensional control of peak wavelength and intensity without excessive reliance on material properties.

[0030] The method of this invention changes the plasmon resonance mode of the structure at the slit location by applying a voltage, thereby changing the peak wavelength and intensity of the spectrum, and thus achieving multi-dimensional control of thermal radiation. The structural patterns and material types selected in this method are highly interchangeable.

[0031] Beneficial effects

[0032] 1. This invention proposes a metasurface composite helical metal structure design. By applying voltage to induce structural deformation, multi-dimensional control of the spectral peak wavelength and spectral intensity can be achieved. The method of controlling the metal metasurface in this invention is achieved through direct voltage application, which is simpler than other methods that control temperature or thermal phase transitions and does not involve complex, uncontrollable chemical reactions. The multi-dimensional variation of the thermal radiation spectrum of the proposed metal helical cantilever array structure overcomes the limitations of existing technologies that can only adjust the spectral peak wavelength or only adjust the spectral intensity within a small range. Furthermore, the compatibility of this invention with various materials solves the problem of other methods relying excessively on the inherent properties of the materials themselves.

[0033] 2. This invention achieves radiation heat management and temperature control functions for metasurface structures by applying voltage to the structure, thereby changing the plasmon resonance mode of the structure at the slit position.

[0034] 3. The electronic control method used in this invention can continuously adjust the thermal radiation spectrum, and the process is reversible. The method proposed in this invention has strong compatibility, applicable not only to various thread patterns and metal materials, but also to various periodic parameters, thus it can be adapted to a wide range of scenarios with few limitations. Attached Figure Description

[0035] Figure 1 This refers to the existing technology for controlling the thermal radiation spectrum;

[0036] Figure 2 Example 1 illustrates the structure and application of a metal spiral cantilever array.

[0037] Figure 3 The results of thermal radiation spectrum intensity adjustment in the application of the metal spiral cantilever array structure in Example 1 are shown.

[0038] Figure 4 Example 2 illustrates the structure and application of a metal spiral cantilever array.

[0039] Figure 5 The results of adjusting the peak wavelength of the thermal radiation spectrum when applied to the metal spiral cantilever array structure in Example 2;

[0040] Figure 6 The results show the structural temperature regulation when the metal spiral cantilever array structure is applied in Example 3. Detailed Implementation

[0041] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0042] Example 1

[0043] The fabrication method based on a metal spiral cantilever array structure includes the following steps:

[0044] Step 1: Continuously deposit a 5nm thick layer of chromium and a 60nm thick layer of aluminum on the substrate. The substrate consists of two layers: an upper layer of silicon dioxide and a lower layer of silicon.

[0045] Step 2: Using a focused ion beam, a composite helical structure pattern array is etched onto the above sample. Gallium ions are used, with a dose of 1.9 × 10⁻⁶. 8 Pieces / mm (600pCμm) -2 The accelerating voltage and current beam for gallium ions were set to 30 kV and 80 pA, respectively, with an etching depth reaching the silicon substrate. The etching pattern was a composite spiral array structure, with each array unit containing three windmill-shaped spirals internally and six Archimedean spirals externally. The parametric equation for the windmill-shaped spiral is as follows:

[0046]

[0047]

[0048] Where α is an angular parameter, ranging from 0.8 to 45 degrees. * indicates multiplication.

[0049] The parameterization equation for the Archimedean spiral is:

[0050] x = (1.8 + 1.3θ) * cos(θ)

[0051] y = (1.8 + 1.3θ) * sin(θ)

[0052] Where θ is an angular parameter, ranging from 200 to 380 degrees in degrees. * indicates multiplication. The three windmill spirals each have a linewidth of 80 nm, and the six Archimedean spirals each have a linewidth of 80 nm. The period of a single array is 3.25 μm.

[0053] Step 3: Use 20% hydrofluoric acid to etch the silicon dioxide beneath the aluminum pattern to form supports that suspend the aluminum structure, such as... Figure 2 As shown, this is the space for subsequent electronically controlled deformation manufacturing;

[0054] Step 4: Connect the positive and negative terminals of a power supply to the aluminum film and silicon substrate respectively, apply a voltage to the structure to cause deformation, and test the adjustable thermal radiation spectrum intensity of the metasurface based on the metal spiral cantilever array structure. Figure 3 As shown, voltages are applied to the upper surface of an aluminum composite spiral pattern metasurface and a silicon substrate, respectively. In this example, the voltage can be repeatedly adjusted between 0V and 26V, causing the aluminum structure to undergo continuous reciprocating deformation in response to voltage changes. Simultaneously, the spectral intensity of this structure also changes with the voltage.

[0055] Example 2

[0056] like Figure 4 As shown, the fabrication method based on the metal spiral cantilever array structure includes the following steps:

[0057] Step 1: Continuously deposit 5 nm thick chromium and 60 nm thick molybdenum on the substrate.

[0058] Step 2: Spin-coat an electron beam resist agent onto the metal surface.

[0059] Step 3: Electron beam exposure and development are performed on the electron beam resist. The developed pattern is a composite spiral array structure, with each array containing three windmill spirals internally and four Archimedean spirals externally. The parameterized equation for the windmill spiral is as follows:

[0060]

[0061]

[0062] Where α is an angular parameter, ranging from 0.8 to 40 degrees. * indicates multiplication.

[0063] The parameterization equation for the Archimedean spiral is:

[0064] x = (1.8 + 1.3θ) * cos(θ)

[0065] y = (1.8 + 1.3θ) * sin(θ)

[0066] Where θ is an angular parameter, ranging from 100 to 380 degrees in degrees. * indicates multiplication. Each stripe has a linewidth of 80 nm, and the period of a single periodic structure is 3.25 μm.

[0067] Step 4: Perform focused ion beam etching on the exposed structure, with the etching depth reaching the silicon substrate.

[0068] Step 5: Use acetone solution to remove excess electron beam resist to obtain the final pattern. Then use 20% hydrofluoric acid to etch the silicon dioxide layer beneath the molybdenum pattern to form pillars that suspend the molybdenum structure, creating space for subsequent electrically controlled deformation.

[0069] Step Six: Connect the negative and positive terminals of the power supply to the fabricated molybdenum metasurface and silicon substrate respectively, and apply voltage to the structure to cause deformation.

[0070] Figure 5 The image shows the morphological changes of a molybdenum-based composite spiral metasurface before and after applying voltage, as well as the resulting peak wavelengths of its thermal radiation spectrum. Specifically:

[0071] In this example, a voltage is applied to a silicon substrate and a patterned molybdenum layer on a molybdenum composite spiral metasurface. The voltage can be adjusted repeatedly between 0V and 1.8V, causing the molybdenum structure to undergo continuous reciprocating deformation as the voltage changes. Simultaneously, the peak wavelength of the spectrum also shifts repeatedly with the voltage change.

[0072] Example 3

[0073] In Example 2, the upper surface of the molybdenum structure and the silicon substrate were connected to the negative and positive terminals of a power supply, respectively. A voltage was applied to the structure to cause it to deform.

[0074] The structural temperature was measured under different voltage conditions when the ambient temperature was 25℃.

[0075] Figure 6 The image shows the temperature change of a molybdenum-based composite spiral metasurface during the application of voltage.

[0076] A voltage is applied to both the upper surface of a molybdenum composite spiral metasurface and a silicon substrate. In this example, the voltage is continuously adjustable. As the voltage increases, the structure deforms, allowing more solar radiation to pass through. Simultaneously, the infrared emission peak shifts from within the atmospheric transparency window to the outer band, reducing radiative cooling power, and vice versa. Therefore, the net power change of the metallic metasurface in equilibrium manifests as a change in structural temperature.

[0077] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A metal-spiral cantilever array structure based on, characterized by The preparation method of the metal spiral cantilever array structure is as follows: Step 1: depositing a chromium layer on a substrate, and depositing a metal layer on the chromium layer; the substrate comprises two layers, the upper layer is silicon dioxide, and the lower layer is silicon; Step 2: etching a composite spiral line structure pattern array on the sample obtained in step 1, and etching to the silicon substrate, the inside of each composite spiral line structure pattern is a windmill type spiral, and the outside is an Archimedes spiral; Step 3: etching the silicon dioxide under the metal layer pattern to obtain a metal spiral cantilever array structure.

2. The metal spiral cantilever array structure according to claim 1, wherein: in step 1, the thickness of the deposited chromium layer is 5-10 nm, and the thickness of the deposited metal layer is 60-100 nm.

3. The metal spiral cantilever array structure according to claim 1, wherein: the single structure design pattern of the metal spiral cantilever array structure is a composite spiral, which is composed of a windmill type spiral inside and an Archimedes spiral outside; the parametric equation of the windmill type spiral is: the parametric equation of the Archimedes spiral is: the windmill type spiral is three or four; wherein is an angle parameter with a value of 0.8-45, angle in °, * means multiplication; when the windmill type spiral is three, the angle in the parametric equation of the windmill type spiral is 0.8-50°; wherein is an angle parameter with a value of 200-380, the angle is denoted by °* when the windmill type spiral is four, the angle in the parametric equation of the windmill type spiral is 0.8-45°; the Archimedes spiral is three, four, five or six; when the Archimedes spiral is three, the angle in the parametric equation of the Archimedes spiral is 50-380°; when the Archimedes spiral is four, the angle in the parametric equation of the Archimedes spiral is 100-380°; when the Archimedes spiral is five, the angle in the parametric equation of the Archimedes spiral is 150-380°; when the Archimedes spiral is six, the angle in the parametric equation of the Archimedes spiral is 200-380°; the line width of the windmill type spiral is 60-150 nm; the line width of the Archimedes spiral is 60-150 nm; the period size of a single array is 3.25-5 μm.

4. The metal spiral cantilever array structure according to claim 1, wherein: in step 2, a focused ion beam etching technology or an electron beam exposure development technology is used to etch the composite spiral line structure pattern array; 5. The metal spiral cantilever array structure according to claim 1, wherein: in step 3, hydrofluoric acid is used to etch the silicon dioxide under the aluminum layer. The metal layer is aluminum, gold, molybdenum, copper or magnesium.

7. Use of the metal spiral cantilever array structure according to any one of claims 1-6, wherein: a voltage is applied to the upper and lower surfaces of the metal spiral cantilever array structure, and the electrostatic attraction between the metal layer and the silicon drives the pattern of the metal spiral cantilever array structure to reciprocally deform with the increase and decrease of the voltage.

8. The use of the metal spiral cantilever array structure according to claim 7, wherein: ​ 6. The metal meander cantilever array structure according to claim 1, wherein: ​ ​ ​ ​ The pattern of the metal spiral cantilever array structure is deformed, so that the thermal radiation spectrum of the metal spiral cantilever array structure changes multidimensionally, including changes in spectral peak wavelength and spectral intensity.

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