A narrow-band van der waals phonon polariton-based thermal emitter and a method of preparation

Abstract

The present application relates to the technical field of narrow-band thermal radiator, more particularly to a narrow-band thermal radiator based on van der Waals phonon polaritons and a preparation method, the preparation method comprising: S1. taking a reflective substrate, and performing modification treatment on the surface of the reflective substrate; S2. taking a van der Waals phonon polariton material layer, transferring the van der Waals phonon polariton material layer to the surface of the modified reflective substrate, and then performing flattening treatment; S3. performing annealing treatment on the sample after the flattening treatment; the narrow-band thermal radiator comprises a substrate layer, a metal surface roughening layer stacked on the substrate layer, and further comprises a van der Waals phonon polariton material layer or a van der Waals phonon polariton patterning structure layer arranged on the metal surface roughening layer. The present application can realize a smooth and ultra-compact narrow-band infrared thermal radiator.

Description

Technical Field

[0001] This invention relates to the technical field of narrowband thermal radiators, and more specifically, to a narrowband thermal radiator based on van der Waals phonon polaritons and its fabrication method. Background Technology

[0002] Thermal radiation is an electromagnetic wave generated by the thermal motion of charged particles within matter, and it has wide applications in infrared remote sensing, thermal imaging, and thermal management. However, natural materials typically exhibit broad-spectrum, non-polarized, and incoherent thermal radiation characteristics, and their large size makes on-chip integration difficult. To address these issues, researchers often use noble metals or semiconductor materials to construct three-dimensional photonic crystals, optical micro / nano structures, or plasmonic structures to increase the degree of freedom in controlling thermal radiation and achieve wavelength and polarization selectivity. However, thermal radiation devices based on traditional noble metals and semiconductor materials suffer from large size and difficulty in integration. In particular, plasmonic structures based on noble metals exhibit significant optical losses, resulting in low thermal radiation efficiency. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the low thermal radiation efficiency of existing plasmonic structures and to provide a narrowband thermal radiator based on van der Waals phonon polaritons and its fabrication method, which can realize a smooth, flat and ultra-compact narrowband infrared thermal radiation device.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A method for fabricating a narrowband thermal radiator based on van der Waals phonon polaritons is provided, comprising the following steps: S1. Take a reflective substrate and modify the surface of the reflective substrate; S2. Take the van der Waals phonon material layer, transfer the van der Waals phonon material layer to the surface of the modified reflective substrate, and then perform a flattening process. S3. Anneal the flattened sample.

[0005] This invention discloses a method for fabricating a narrowband thermal radiator based on van der Waals phonon polaritons. By modifying the surface of a reflective substrate, the adhesion of the substrate can be controlled, facilitating the direct bonding of the van der Waals phonon polariton material layer to the reflective substrate. Flattening the van der Waals phonon polariton material layer reduces cavitation and wrinkles, improving its flatness. Annealing the reflective substrate with the stacked van der Waals phonon polariton material layer further removes interface bubbles, promotes bonding, and improves material stability and polariton response. By directly bonding the van der Waals phonon polariton material layer to the reflective substrate, the van der Waals phonon polariton material layer and the reflective substrate are mirror-coupled to form a narrowband thermal radiation response, thus forming a narrowband thermal radiator.

[0006] Further, step S1 includes the following steps: S11. Take the reflective substrate and perform ultrasonic cleaning on the surface of the reflective substrate; S12. The surface of the reflective substrate is etched using a reactive ion beam to obtain a rough surface.

[0007] Furthermore, the reflective substrate includes a substrate layer and a gold film layer stacked on the substrate layer. In step S12, the gold film layer is etched to obtain a metal surface roughening layer.

[0008] Furthermore, in step S2, the van der Waals phonon material layer is any one of hexagonal boron nitride, orthorhombic molybdenum trioxide, orthorhombic vanadium pentoxide.

[0009] Further, step S2 includes the following steps: S21. Take the van der Waals phonon material layer, place the van der Waals phonon material layer on the surface of the modified reflective substrate and perform preliminary flattening; S22. Add an auxiliary spreading liquid to the surface of the modified reflective substrate until the auxiliary spreading liquid is completely spread on the surface of the reflective substrate, and then let it stand and air dry.

[0010] Further, in step S3, the gas used for annealing is at least one of O2 and Ar; and / or, the volumetric flow rate of the gas during annealing is 100~500 sccm, the annealing temperature is 120~450℃, and the annealing time is 60~300 min.

[0011] Furthermore, it also includes step S4: patterning the surface of the annealed van der Waals phonon material layer, and then etching it to obtain a van der Waals phonon patterned structure layer, forming a narrowband thermal radiator based on van der Waals phonon polaritons.

[0012] Further, step S4 includes the following steps: S41. The surface of the annealed van der Waals phonon material layer is sequentially coated with photoresist, hardened, exposed, and developed. S42. The van der Waals phonon material layer processed in step S41 is etched using a reactive ion beam to obtain a van der Waals phonon patterned structure layer. S43. Perform plasma cleaning on the patterned structure layer of van der Waals phonon polaritons to obtain a narrowband thermal radiator based on van der Waals phonon polaritons.

[0013] Furthermore, the van der Waals phonon patterned structure layer includes any one or more of the van der Waals phonon micro / nano structure layer and polygon structure layer.

[0014] The present invention also provides a narrowband thermal radiator based on van der Waals phonon polaritons, comprising a substrate layer, a metal surface roughening layer stacked on the substrate layer, and a van der Waals phonon polariton material layer or a van der Waals phonon polariton patterned structure layer disposed on the metal surface roughening layer; the material of the van der Waals phonon polariton material layer or the van der Waals phonon polariton patterned structure layer is any one of hexagonal boron nitride, orthorhombic molybdenum trioxide, orthorhombic vanadium pentoxide; the metal in the metal surface roughening layer is Au.

[0015] Compared with the prior art, the beneficial effects of the present invention are: This invention discloses a narrowband thermal radiator based on van der Waals phonon polaritons and its fabrication method. By modifying the surface of a reflective substrate, the adhesion of the substrate can be controlled, facilitating the direct bonding of the van der Waals phonon polariton material layer to the reflective substrate. Flattening the van der Waals phonon polariton material layer reduces cavitation and wrinkles, improving its flatness. Annealing the reflective substrate with the stacked van der Waals phonon polariton material layer further removes interface bubbles, promotes bonding, and improves material stability and polariton response. By directly bonding the van der Waals phonon polariton material layer to the reflective substrate, the van der Waals phonon polariton material layer and the reflective substrate are mirror-coupled to form a narrowband thermal radiation response, thus forming a narrowband thermal radiator. Attached Figure Description

[0016] Figure 1 This is a flowchart of the first embodiment of a method for fabricating a narrowband thermal radiator based on van der Waals phonon polaritons according to the present invention; Figure 2 This is a flowchart of a second embodiment of a method for fabricating a narrowband thermal radiator based on van der Waals phonon polaritons according to the present invention; Figure 3 This is a flowchart and comparative diagram of step S1 of the preparation method of the present invention; Figure 4 This is a flowchart and comparative diagram of step S2 of the preparation method of the present invention; Figure 5 This is a flowchart and comparative diagram of step S3 in the preparation method of the present invention; Figure 6 This is a flowchart and comparative diagram of step S4 of the preparation method of the present invention; Figure 7 AFM image of the narrowband thermal radiator prepared according to the present invention; Figure 8 The Fourier transform infrared spectrum of the narrowband thermal radiator prepared in this invention; Figure 9 This is a schematic diagram of the structure of a first embodiment of a narrowband thermal radiator based on van der Waals phonon polaritons according to the present invention. Figure 10 This is a schematic diagram of the structure of a second embodiment of a narrowband thermal radiator based on van der Waals phonon polaritons according to the present invention. Figure 11 This is a schematic diagram of the third embodiment of a narrowband thermal radiator based on van der Waals phonon polaritons according to the present invention.

[0017] In the attached figures: 100, substrate layer; 200, metal surface roughening layer; 300, van der Waals phonon material layer; 310, van der Waals phonon patterned structure layer. Detailed Implementation

[0018] The present invention will be further described below with reference to specific embodiments. The accompanying drawings are for illustrative purposes only, representing schematic diagrams rather than actual physical objects, and should not be construed as limiting the scope of this patent. To better illustrate the embodiments of the present invention, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0019] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0020] Example 1 like Figure 1 , Figures 3 to 5 , Figure 9 The image shows a first embodiment of a method for fabricating a narrowband thermal radiator based on van der Waals phonon polaritons according to the present invention, comprising the following steps: S1. Take a reflective substrate and modify its surface. S2. Take the van der Waals phonon material layer 300, transfer the van der Waals phonon material layer 300 to the surface of the modified reflective substrate, and then flatten it. S3. Anneal the flattened sample.

[0021] This invention modifies the surface of the reflective substrate to control its adhesion, facilitating direct bonding of the van der Waals phonon material layer 300 to the reflective substrate. Flattening the van der Waals phonon material layer 300 reduces voids and wrinkles, improving its flatness. Annealing the reflective substrate with the van der Waals phonon material layer 300 further removes interface bubbles, promotes bonding, and improves material stability and polaron response. By directly bonding the van der Waals phonon material layer 300 to the reflective substrate, the van der Waals phonon material layer 300 and the reflective substrate are mirror-coupled to form a narrowband thermal radiation response, creating a narrowband thermal radiator. Figure 9 As shown.

[0022] In this embodiment, the reflective substrate includes a substrate layer 100 and a gold film layer stacked on the substrate layer 100. In this embodiment, the substrate layer 100 is a silicon substrate, specifically, a double-sided polished high-resistivity silicon wafer. In this embodiment, when preparing the reflective substrate, a 1cm*1cm double-sided polished high-resistivity silicon wafer with a thickness of 500 μm can be selected. Then, Au is selected as the target material. Specifically, Au particles with a purity of 99.999% are used as the target material, and the reflective substrate is prepared by electron beam vacuum evaporation or DC magnetron sputtering.

[0023] Step S1 includes the following steps: S11. Take the reflective substrate and perform ultrasonic cleaning on the surface of the reflective substrate. In this embodiment, acetone, anhydrous ethanol and deionized water are used for ultrasonic cleaning in sequence. The cleaning frequency is 28~40kHz, the cleaning power is 200~500W, and the cleaning time is 5~60 min. S12. The surface of the gold film layer on the reflective substrate is etched using a reactive ion beam to obtain a metal surface roughening layer 200. In this embodiment, the reactive gas used during etching includes at least two of CF4, CFH3, O2, and Ar. The etching power is 100~500 W and the etching time is 5~20 min.

[0024] Specifically, in step S11, acetone is used to ultrasonically clean the surface of the reflective substrate to remove organic contaminants such as grease adhering to the surface; then anhydrous ethanol is used for ultrasonic cleaning to further clean and remove residual acetone; finally, deionized water is used for ultrasonic cleaning to separate large particulate contaminants on the surface of the reflective substrate and wash away residual organic solvents; then, it is dried by purging with nitrogen. In step S11, the cleaning frequency of 28~40kHz, the cleaning power of 200~500W, and the cleaning time of 5~60 min are selected to achieve effective cleaning and prevent the gold film layer from peeling off from the substrate layer 100.

[0025] In step S11, when cleaning the reflective substrate using ultrasonic cleaning, acetone, anhydrous ethanol, and deionized water are used for cleaning, and nitrogen is used for drying. Acetone helps remove organic contaminants from the surface of the reflective substrate; anhydrous ethanol is completely miscible with acetone, so it is used to remove residual acetone after cleaning; finally, deionized water is used to remove residual anhydrous ethanol after cleaning. Combined with the ultrasonic cavitation effect, large particulate impurities on the surface of the reflective substrate are stripped off, further enhancing the cleaning effect, thereby obtaining a clean reflective substrate.

[0026] Specifically, in step S12, after nitrogen purging and drying, the reaction chamber is placed in a high vacuum environment (below 10). - (³ Pa), using an independent ion source to generate a focused high-energy ion beam, typically inert gas ions such as Ar. + The gold film layer is targeted and bombarded by ions, while reactive gases such as CF4 are directly injected into the vicinity of the gold film surface in the ion beam bombardment area. Under the combined effect of the physical bombardment of high-energy ions and the chemical reaction between the reactive gas and the target material (producing volatile organic compounds), part of the surface lattice of the gold film layer is efficiently and highly anisotropically removed. Before transferring the van der Waals phonon material layer 300, the morphology and chemical properties of the reflective substrate surface are controlled by reactive ion etching, in which high-energy Ar... + Ions physically bombard and disrupt the crystal lattice of the reflective substrate, forming nanoscale pits and trenches on the gold film surface, significantly increasing surface roughness. Simultaneously, reactive gases chemically react with the gold film on the reflective substrate surface, selectively removing surface atoms to amplify the roughening effect. Furthermore, preferably, O2 is introduced to react with the etched and exposed reflective substrate surface, generating a highly polar oxide layer that significantly enhances surface hydrophilicity. In step S12, by adjusting the RF power, chamber pressure, and etching time, the roughened surface enhances material adhesion through mechanical interlocking, improves polar groups to aid subsequent wafer unfolding, and the synergistic effect of surface property reconstruction and chemical modification facilitates the removal of interfacial gases in subsequent processing steps.

[0027] Preferably, in step S12, the reactive gases for the reactive ion beam etching process can be O2 and CF4, and the flow ratio of O2 to CF4 is set to 2:3 to 6:1, the cavity gas pressure is set to 30 to 180 mTorr, the etching power is 50 to 300 W, and the etching time is 5 to 15 min.

[0028] like Figure 3 As shown, Figure 3 (a) is a schematic diagram of the principle of surface treatment of reflective substrate based on ultrasonic cleaning in step S11 and reactive ion beam etching in step S12. Figure 3 (b) is the AFM image of the gold film on the surface of the reflective substrate without reactive ion beam etching. Figure 3 (c) is the AFM image of the gold film layer after step S1; Figure 3 (b) and Figure 3 In (c), the scale bar is 1 μm, and RMS is the root mean square value of the height of the gold film surface profile deviating from the reference plane within the test range. A larger RMS value indicates a greater surface roughness of the gold film. Figure 3 It can be seen that reactive ion beam etching can effectively improve the surface roughness of the gold film layer, increasing the surface roughness from 0.739 nm to 0.822 nm after treatment.

[0029] In this embodiment, in step S2, the van der Waals phonon material layer 300 is any one of hexagonal boron nitride (h-BN), orthorhombic molybdenum trioxide (α-MoO3), orthorhombic vanadium pentoxide (α-V2O5). Preferably, orthorhombic molybdenum trioxide (α-MoO3) is selected in this embodiment.

[0030] In this embodiment, step S2 includes the following steps: S21. Take the van der Waals phonon material layer 300, place the van der Waals phonon material layer 300 on the surface of the modified reflective substrate and flatten it initially; specifically, use tweezers or other gripping tools to grip the van der Waals phonon material layer 300 grown by physical vapor deposition onto the surface of the reflective substrate, flatten the van der Waals phonon material layer 300 initially and fit it as closely as possible to the surface of the metal surface roughening layer 200. S22. Add an auxiliary spreading liquid to the surface of the modified reflective substrate until the auxiliary spreading liquid is completely spread on the surface of the reflective substrate, and then let it stand to air dry; specifically, use a pointed dropper to draw up the auxiliary spreading liquid and slowly drip it onto the surface of the metal surface roughening layer 200; after the auxiliary spreading liquid is completely spread on the surface of the metal surface roughening layer 200, let it stand; then, by natural air drying or by using a hot plate to accelerate the evaporation of the auxiliary spreading liquid on the surface of the metal surface roughening layer 200, the van der Waals phonon material layer 300 is tightly attached to the metal surface roughening layer 200.

[0031] In step S22, the auxiliary spreading liquid is at least one of isopropanol and anhydrous ethanol, and the amount of auxiliary spreading liquid used is 0.05~0.1 mL. The operating environment temperature is 25℃ and the humidity is ≤35%RH. Preferably, isopropanol is selected as the auxiliary spreading liquid. During the drying process, a hot plate can be used to heat the reflective substrate with aluminum foil as a barrier to reduce the residue of the auxiliary liquid. The heating temperature is ≤100℃. After step S22, the area of ​​the van der Waals phonon material layer 300 is ≥1 mm². 2 The thickness is 50-500nm.

[0032] like Figure 4 As shown, Figure 4 (a) is a flowchart of step S2 of the present invention, which includes: transferring a van der Waals phonon material layer 300 on a reflective substrate; dropping isopropanol onto the reflective substrate on which the van der Waals phonon material layer 300 is placed, using isopropanol to reduce surface tension and regulate the wettability of the contact interface, promoting the uniform spreading of the van der Waals phonon material layer 300, and effectively removing residual gas at the interface; at the same time, the controllable evaporation rate of isopropanol can achieve the gradual bonding of the van der Waals phonon material layer 300, avoiding wrinkles or cracks caused by instantaneous stress. In addition, the hydroxyl groups in isopropanol molecules can form hydrogen bonds or van der Waals forces with the surface of the metal surface roughening layer 200 after reactive ion beam etching, which helps the van der Waals phonon material layer 300 to make close contact with the metal surface roughening layer 200 during the bonding process and reduces interfacial slippage. Isopropanol, as a liquid carrier, alleviates mechanical stress concentration through liquid film lubrication during the transfer process, avoiding local strain accumulation or tearing of the van der Waals phonon material layer 300, thereby maintaining the structural integrity of the material. Finally, drying is performed. Figure 4 (b) An optical microscope image of the van der Waals phonon material layer 300 after step S22, showing the selection of an α-MoO3 thin film. Figure 4 (c) An optical microscope image of the van der Waals phonon material layer 300, selected as an α-MoO3 thin film, transferred to the surface of the metal surface roughening layer 200, without the use of isopropanol as an auxiliary spreading liquid. Figure 4 (b) and Figure 4In (c), the scale is 100 μm; by Figure 4 It can be seen that when isopropanol is not used to assist bonding during the transfer process, the surface contact between the van der Waals phonon material layer 300 and the metal surface roughening layer 200 is poor, resulting in large-area cavitation. In contrast... Figure 4 (a) and Figure 4 (b) It can be seen that isopropanol can effectively assist the flattening of the van der Waals phonon material layer 300 during the transfer process, and promote the adhesion of the van der Waals phonon material layer 300 to the surface of the metal surface roughening layer 200.

[0033] In this embodiment, in step S3, the gas used for annealing is at least one of O2 and Ar; and / or, the gas volumetric flow rate during annealing is 100~500 sccm, the annealing temperature is 120~450℃, and the annealing time is 60~300 min. Preferably, O2 is selected for annealing. Annealing with O2 can repair oxygen defects in the van der Waals phonon material layer 300, promote the formation of a stable phase in the van der Waals phonon material layer 300, improve chemical stability, inhibit surface reduction reactions, and ensure catalytic or electrochemical activity.

[0034] like Figure 5 As shown, Figure 5 (a) An optical microscope image of α-MoO3 thin film selected for unannealed van der Waals phonon material layer 300. Figure 5 (b) An optical microscope image of the α-MoO3 thin film selected from the annealed van der Waals phonon material layer 300; Figure 5 (a) and Figure 5 In (b), the scale bar is 100 μm. Figure 5 (c) is a schematic diagram of the annealing process performed in step S3. Figure 5 (d) is a SEM image of the sample after annealing in step S3. Figure 5 (d) The scale is 500 μm. Figure 5It is evident that, before annealing, some bubbles formed by residual isopropanol during the transfer process exist in the van der Waals phonon material layer 300 on the surface of the metal surface roughening layer 200. After annealing, these bubbles in the van der Waals phonon material layer 300 on the surface of the metal surface roughening layer 200 can be effectively eliminated. Through the annealing process in step S3 of this invention, a large-area transfer of the van der Waals phonon material layer 300 can be achieved on the reflective substrate surface. Through the annealing process, utilizing the synergistic effect of gas diffusion and interface reconstruction under thermal excitation, the organic solvent and gas molecules remaining in the van der Waals phonon material layer 300 can diffuse outward, while simultaneously promoting local atomic rearrangement between the van der Waals phonon material layer 300 and the surface of the metal surface roughening layer 200, thereby enhancing the interfacial adhesion between the van der Waals phonon material layer 300 and the metal surface roughening layer 200.

[0035] This invention utilizes phonon polaritons based on van der Waals polar materials to exhibit unique properties superior to traditional plasmons. Phonon polaritons are formed by the coupling of incident electromagnetic waves with lattice vibrations in polar crystals, representing an electromagnetic mode with collective oscillation characteristics. The most significant features of this invention are extremely low optical loss, enhanced resonant wavelength response, and narrower resonant peak width. When orthorhombic molybdenum trioxide (α-MoO3) is selected, as a biaxial hyperbolic van der Waals material, it supports in-plane anisotropic phonon polaritons with ultra-low loss, enabling strong coupling with mid-infrared light and generating polariton modes with ultra-long lifetimes.

[0036] Example 2 This embodiment is a second embodiment of a method for fabricating a narrowband thermal radiator based on van der Waals phonon polaritons. This embodiment is similar to Embodiment 1, except that, as Figure 2 , Figures 6 to 8 As shown, this embodiment also includes step S4: patterning the surface of the annealed van der Waals phonon material layer 300, and then performing an etching process to obtain a van der Waals phonon patterned structure layer 310, forming a narrowband thermal radiator based on van der Waals phonon polaritons.

[0037] Specifically, step S4 includes the following steps: S41. The surface of the annealed van der Waals phonon material layer 300 is sequentially coated with photoresist, hardened, exposed, and developed. Specifically, the van der Waals phonon material layer 300 is pre-patterned using electron beam exposure or maskless exposure. In this embodiment, pre-patterning refers to modifying the photoresist in a specific area on the surface of the already spin-coated van der Waals phonon material layer 300 through exposure, so that the photoresist layer displays the corresponding pattern after development. In step S41, the photoresist selected is PMMA (A7), the spin coater speed is 2000~7000 rpm, the hardening temperature is 120~200℃, and the hardening time is 150~300s. The exposure process is electron beam exposure, with an electron beam current of 1~10nA and an electron beam dose of 300~500 μC / cm². 2 During the developing process, MIBK, isopropanol, and deionized water are used for immersion for 2-6 minutes.

[0038] S42. The van der Waals phonon material layer 300 after step S41 is etched using a reactive ion beam to obtain a van der Waals phonon patterned structure layer 310. The etching is performed using a reactive ion etching process, and the etching gas includes at least two of O2, CF4, CHF3, and Ar. Preferably, the etching gas is O2, CHF3, and Ar, with a flow rate ratio of (1-3):(10-15):(1-3). The etching power is 10~100 W, and the etching time is 5~30 min.

[0039] S43. The van der Waals phonon patterned structure layer 310 is subjected to plasma cleaning to obtain a narrowband thermal radiator based on van der Waals phonon polaritons. In this embodiment, plasma cleaning is used to remove impurity particles such as residual adhesive. The reaction gas is selected as Ar or O2, the power is 10~100 W, and the cleaning time is 5~30 min. Preferably, O2 is selected as the reaction gas for plasma cleaning. The highly reactive oxygen free radicals in the oxygen plasma can achieve efficient adhesive removal through oxidation and decomposition reaction with organic materials such as photoresist. At the same time, the high-speed bombardment of oxygen ions generates a physical sputtering effect, stripping away unreacted residues. The decomposition efficiency of oxygen plasma on organic colloids is significantly higher than that on inorganic materials. It can accurately remove the adhesive layer without damaging the reflective substrate. Meanwhile, the reaction products (CO2, H2O) can volatilize, leaving no obvious chemical residues.

[0040] The van der Waals phonon patterned structure layer 310 includes any one or more of van der Waals phonon micro / nano structure layers and polygonal structure layers; in this embodiment, the van der Waals phonon patterned structure layer 310 is a van der Waals phonon micro / nano structure layer, that is, in step S41, the corresponding pattern is a nanoribbon array pattern, such as... Figure 6 As shown, the obtained van der Waals phonon micro / nano structure layer is a van der Waals phonon micro / nano structure array. Specifically, the micro / nano structure is a grating structure composed of several nano-strips, with each individual having an area ≥ 0.25 mm². 2 ,like Figure 10 As shown.

[0041] like Figure 6 As shown, in Figure 6 (a) is a flowchart of step S4 of the present invention, which includes: placing a van der Waals phonon material layer 300 with an electron beam resist uniformly spin-coated on its surface in a high vacuum cavity; focusing an electron beam to a spot with a diameter of several nanometers using an electromagnetic lens; computer-controlled scanning of the spot according to a preset pattern on the resist surface; the interaction between the high-energy beam and the resist molecules causing molecular chain breakage (positive resist) or cross-linking (negative resist) in the exposed area, triggering a change in chemical properties; then immersing the sample in a specific solvent for development, forming a bond with the resist by dissolving the exposed area. Figure 1 A resist mask is formed; then, reactive ion etching is used to form a pattern consistent with the resist mask on the reflective substrate. The areas not covered by the resist are selectively removed under the action of plasma; finally, the residual resist is removed using the corresponding resist remover to obtain a high-precision van der Waals phonon patterned structure layer 310.

[0042] Figure 6 (b) An optical image of the van der Waals phonon patterned structure layer 310 on the surface of the prepared metal surface roughening layer 200. Figure 6 (b) The scale is 200 μm. Figure 6 Figures (c) to (f) are optical images of an infrared narrowband thermal radiator fabricated from van der Waals phonon patterned layer 310 using a grating structure composed of nanostrips with grating feature sizes of 0.8 μm, 1.0 μm, 1.2 μm, and 1.5 μm. Figure 6 In Figures (c) to (f), the scale bar is 2 μm.

[0043] like Figure 7 As shown, Figure 7 (a) An AFM image of the van der Waals phonon material layer 300 on the surface of the metal surface roughening layer 200 obtained after annealing. Figure 7 (a) The scale bar is 2 μm. RMS is the root mean square value of the height of the profile surface deviating from the reference plane when the van der Waals phonon material layer 300 is selected as the α-MoO3 film within the test range. The larger the RMS value, the greater the surface roughness of the α-MoO3 film. Figure 7 (b)~ Figure 7(e) is an AFM image of an infrared narrowband thermal radiator fabricated from van der Waals phonon patterned layer 310 using a grating structure composed of nanostrips with grating feature sizes of 0.8 μm, 1.0 μm, 1.2 μm, and 1.5 μm. The scale bar in the image is 2 μm. Figure 7 (a) It can be seen that the surface roughness of the α-MoO3 film on the surface of the metal surface roughening layer 200 is 0.621 nm. Through the processing in steps S2 and S3 of this invention, a highly flat α-MoO3 film can be transferred onto the reflective substrate surface. Figures 5 to 7 It can be seen that the van der Waals phonon patterned structure layer 310 on the substrate surface prepared by the present invention has high surface flatness and thickness uniformity, and smooth and clear contours, which meets the structural requirements of radiation devices.

[0044] like Figure 8 As shown, Figure 8 (a) is the Fourier transform infrared absorption spectrum of the α-MoO3 thin film on the surface of the infrared narrowband thermal radiator metal surface roughening layer 200, which was prepared after step S3 (under T=297K) with thicknesses of 251 nm, 203 nm and 151 nm of the van der Waals phonon patterned structure layer 310. Figure 8 (b) is the Fourier transform infrared radiation spectrum of the α-MoO3 thin film on the surface of the infrared narrowband thermal radiator metal surface roughening layer 200, which was prepared after step S3 (at T=373K) with thicknesses of 251 nm, 203 nm and 151 nm of the van der Waals phonon patterned structure layer 310. Figure 8 (c) is the normalized Fourier transform infrared absorption spectrum of the infrared narrowband thermal radiator prepared by the van der Waals phonon patterned structure layer 310 after the treatment in step S3 (at T=297K) through a grating structure composed of nanostrips with grating feature sizes of 0.8μm, 1.0 μm, 1.2 μm and 1.5μm. Figure 8 (d) is the normalized Fourier transform infrared radiation spectrum of the infrared narrowband thermal radiator prepared by the van der Waals phonon patterned structure layer 310 after step S3 (at T=473K) through a grating structure composed of nanostrips with grating feature sizes of 0.8 μm, 1.0 μm, 1.2 μm and 1.5 μm.

[0045] Depend on Figure 8 (a) and Figure 8(b) It can be seen that the narrowband thermal radiator prepared by the method of the present invention exhibits typical radiation characteristics in multiple wavelength bands, and displays different radiation intensity characteristics on the van der Waals phonon patterned structure layer 310 with different patterns; furthermore, the radiation spectrum can be modulated by varying the thickness of the van der Waals phonon patterned structure layer 310. Figure 8 (c) and Figure 8 (d) It can be seen that the narrowband thermal radiator prepared by the method of the present invention has typical narrowband radiator characteristics, with the narrowest working linewidth being less than 5cm. -1 Furthermore, the radiation spectrum can be modulated by varying the grating feature sizes of different van der Waals phonon patterned structure layers 310.

[0046] Example 3 This embodiment is the third embodiment of a method for fabricating a narrowband thermal radiator based on van der Waals phonon polaritons. This embodiment is similar to Embodiment Two, except that the van der Waals phonon patterned structure layer 310 is a polygonal structure layer, such as... Figure 11 As shown, the van der Waals phonon patterned structure layer 310 is a polygonal structure layer without cutouts, that is, in step S41, the corresponding pattern is a polygonal structure pattern.

[0047] Example 4 like Figure 9 The illustration shows a first embodiment of a narrowband thermal radiator based on van der Waals phonon polaritons according to the present invention. It includes a substrate layer 100, a metal surface roughening layer 200 stacked on the substrate layer 100, and a van der Waals phonon polariton material layer 300 disposed on the metal surface roughening layer 200. The van der Waals phonon polariton material layer 300 is made of any one of hexagonal boron nitride (h-BN), orthorhombic molybdenum trioxide (α-MoO3), orthorhombic vanadium pentoxide (α-V2O5), with α-MoO3 being preferred. The metal in the metal surface roughening layer 200 is Au. An in-plane localized field-driven terahertz photodetector of this embodiment can be prepared using the preparation method described in Embodiment 1.

[0048] Example 5 This embodiment is a second embodiment of a narrowband thermal radiator based on van der Waals phonon polaritons. This embodiment is similar to embodiment four, except that, as Figure 10As shown, it also includes a van der Waals phonon patterned structure layer 310 disposed on the metal surface roughening layer 200. In this embodiment, the material of the van der Waals phonon patterned structure layer 310 is orthorhombic molybdenum trioxide (α-MoO3). The van der Waals phonon patterned structure layer 310 is a van der Waals phonon micro / nano structure layer. Furthermore, the van der Waals phonon patterned structure layer 310 includes a grating structure composed of several nanostrips. An in-plane localized field-driven terahertz photodetector of this embodiment can be fabricated using the method described in Example 2.

[0049] Example 6 This embodiment is a third embodiment of a narrowband thermal radiator based on van der Waals phonon polaritons. This embodiment is similar to embodiment five, except that, as Figure 11 As shown, the van der Waals phonon patterned structure layer 310 is a polygonal structure layer; preferably, a rectangular structure can be selected for the polygonal structure layer. The in-plane localized field-driven terahertz photodetector of this embodiment can be fabricated using the method described in Example 3.

[0050] In the specific implementation of the above embodiments, the technical features can be combined in any non-contradictory way. For the sake of brevity, not all possible combinations of the above technical features are described. However, as long as the combination of these technical features is not contradictory, it should be considered to be within the scope of this specification.

[0051] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for fabricating a narrowband thermal radiator based on van der Waals phonon polaritons, characterized in that, Includes the following steps: S1. Take a reflective substrate and modify the surface of the reflective substrate; S2. Take the van der Waals phonon material layer (300), transfer the van der Waals phonon material layer (300) to the surface of the modified reflective substrate, and then flatten it. S3. Anneal the flattened sample.

2. The method for fabricating a narrowband thermal radiator based on van der Waals phonon polaritons according to claim 1, characterized in that, Step S1 includes the following steps: S11. Take the reflective substrate and perform ultrasonic cleaning on the surface of the reflective substrate; S12. The surface of the reflective substrate is etched using a reactive ion beam to obtain a rough surface.

3. The method for fabricating a narrowband thermal radiator based on van der Waals phonon polaritons according to claim 2, characterized in that, The reflective substrate includes a substrate layer (100) and a gold film layer stacked on the substrate layer (100). In step S12, the gold film layer is etched to obtain a metal surface roughening layer (200).

4. The method for fabricating a narrowband thermal radiator based on van der Waals phonon polaritons according to claim 1, characterized in that, In step S2, the van der Waals phonon material layer (300) is any one of hexagonal boron nitride, orthorhombic molybdenum trioxide, orthorhombic vanadium pentoxide.

5. The method for fabricating a narrowband thermal radiator based on van der Waals phonon polaritons according to claim 1, characterized in that, Step S2 includes the following steps: S21. Take the van der Waals phonon material layer (300), place the van der Waals phonon material layer (300) on the surface of the modified reflective substrate and perform preliminary flattening; S22. Add an auxiliary spreading liquid to the surface of the modified reflective substrate until the auxiliary spreading liquid is completely spread on the surface of the reflective substrate, and then let it stand and air dry.

6. The method for fabricating a narrowband thermal radiator based on van der Waals phonon polaritons according to claim 1, characterized in that, In step S3, the gas used for annealing is at least one of O2 and Ar; and / or, the volumetric flow rate of the gas during annealing is 100~500 sccm, the annealing temperature is 120~450℃, and the annealing time is 60~300 min.

7. The method for fabricating a narrowband thermal radiator based on van der Waals phonon polaritons according to any one of claims 1 to 6, characterized in that, The process also includes step S4: patterning the surface of the annealed van der Waals phonon material layer (300) and then etching it to obtain a van der Waals phonon patterned structure layer (310), forming a narrowband thermal radiator based on van der Waals phonon polaritons.

8. The method for fabricating a narrowband thermal radiator based on van der Waals phonon polaritons according to claim 7, characterized in that, Step S4 includes the following steps: S41. The surface of the annealed van der Waals phonon material layer (300) is sequentially coated with photoresist, hardened, exposed, and developed. S42. The van der Waals phonon material layer (300) after step S41 is etched using a reactive ion beam to obtain a van der Waals phonon patterned structure layer (310). S43. Perform plasma cleaning on the van der Waals phonon patterned structure layer (310) to obtain a narrowband thermal radiator based on van der Waals phonon polaritons.

9. The method for fabricating a narrowband thermal radiator based on van der Waals phonon polaritons according to claim 8, characterized in that, The van der Waals phonon patterned structure layer (310) includes any one or more of the van der Waals phonon micro / nano structure layer and polygon structure layer.

10. A narrowband thermal radiator based on van der Waals phonon polaritons, characterized in that, The system includes a substrate layer (100), a metal surface roughening layer (200) stacked on the substrate layer (100), and a van der Waals phonon material layer (300) or a van der Waals phonon patterned structure layer (310) disposed on the metal surface roughening layer (200). The material of the van der Waals phonon material layer (300) or the van der Waals phonon patterned structure layer (310) is any one of hexagonal boron nitride, orthorhombic molybdenum trioxide, orthorhombic vanadium pentoxide. The metal in the metal surface roughening layer (200) is Au.

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