A temperature confinement type thermal radiation dynamic regulation device and a preparation method thereof

Abstract

The application discloses a temperature-limited type thermal radiation dynamic regulation device and a preparation method thereof. The device comprises a substrate and a temperature-limited type thermal emission structure arranged on the substrate. The thermal emission structure realizes dynamic regulation of three optical coefficients, i.e. infrared transmission, absorption and reflection, through a VO2-based multilayer film. The thermal emission structure is sequentially provided with a first W-doped VO2 layer, a dielectric layer, a VO2 layer and a second W-doped VO2 layer in a direction away from the substrate. The VO2-based multilayer film structure with different phase transition dynamic characteristics is constructed in the vertical direction of the substrate, so that the device sequentially shows high transmission, high absorption and high reflection states in different temperature intervals, thereby breaking through the limitation that the radiation power of a traditional thermal emission device monotonously changes with temperature.

Description

Technical Field

[0001] This invention relates to the field of dynamic thermal radiation control technology, specifically to a temperature-limited dynamic thermal radiation control device and its fabrication method. Background Technology

[0002] According to the Stefan-Boltzmann law, blackbody radiation power is proportional to the fourth power of absolute temperature. Therefore, for traditional static thermal emissive materials, their surface emissivity is usually fixed, and the infrared radiation intensity of the device increases monotonically with increasing temperature. This fixed and predictable infrared radiation characteristic limits its application in fields such as complex thermal signal modulation, intelligent infrared displays, and dynamic thermal camouflage.

[0003] To overcome the limitations of static thermal emission materials in terms of controllability, researchers have developed various tunable optical materials and dynamic thermal radiation control devices. For example, electrochromic materials, thermochromic materials, mechanochromic materials, and infrared control devices based on VO2 phase change materials can all alter the optical properties of the materials under external stimuli, thereby achieving dynamic adjustment of infrared emissivity, transmittance, or reflectivity. Among these, VO2 is a typical thermochromic phase change material, which can transform from a low-temperature insulating phase to a high-temperature metallic phase near its phase transition temperature, resulting in a significant change in its infrared optical constants. Therefore, it is often used to fabricate smart windows, infrared radiation control devices, and adaptive thermal management devices.

[0004] Existing VO2-based dynamic thermal radiation modulation devices typically utilize changes in infrared transmittance, reflectance, or absorptivity before and after the VO2 phase transition to adjust the device's infrared radiation intensity. For example, VO2 thin films or VO2 multilayer structures can transition from a high-emission state to a low-emission state, or vice versa, during heating, thereby achieving unidirectional infrared radiation modulation. Some studies have also improved the infrared modulation amplitude and spectral selectivity of VO2 devices by constructing metal / dielectric / VO2 multilayer structures, FP cavity structures, or metasurface structures.

[0005] However, existing dynamic thermal radiation modulation technologies still have significant shortcomings. First, the emissivity of traditional static materials is fixed and cannot be actively adjusted according to temperature or external environment; their infrared radiation signals are singular and easily identifiable. Second, existing tunable materials and VO2-based devices are essentially two-state modulation systems, meaning the material or device mainly switches between two optical states (transmission, reflection, and absorption). Their emissivity typically only increases or decreases monotonically with temperature, making it difficult to achieve non-monotonic thermal radiation responses such as "low-high-low" or "high-low-high." Third, existing devices often only allow local modulation of one or two optical parameters in absorption, transmission, or reflection, lacking the ability to dynamically control the global absorption rate, transmittance, and reflectivity, thus making it difficult to overcome the physical limitations of traditional two-state modulation devices. Finally, existing thermal radiation devices typically cannot selectively enhance infrared radiation within a specific temperature window and suppress infrared radiation outside that window, limiting their application in scenarios such as temperature-confined infrared emission, thermal information encryption, and multi-level infrared coding. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a temperature-confined thermal radiation dynamic control device and its fabrication method. By constructing a VO2-based multilayer thin film structure with different phase transition dynamics in the vertical direction of the substrate, the device sequentially exhibits high transmittance, high absorption, and high reflection states in different temperature ranges, thereby breaking through the limitation of the radiation power of traditional thermal emission devices changing monotonically with temperature.

[0007] To address the aforementioned technical problems, the present invention provides a temperature-confined thermal radiation dynamic control device, comprising a substrate and a temperature-confined thermal emission structure disposed on the substrate. The thermal emission structure achieves dynamic control of three optical coefficients—infrared transmission, absorption, and reflection—through a VO2-based multilayer thin film. The thermal emission structure is sequentially arranged with a first W-doped VO2 layer, a dielectric layer, a VO2 layer, and a second W-doped VO2 layer along the direction away from the substrate.

[0008] This invention constructs a VO2-based multilayer thin film structure with different phase transition kinetics in the vertical direction. Due to the different optical responses of the W-doped VO2 (W-VO2) layer and the VO2 layer at different temperatures, at low temperatures, each VO2-based (VO2 / W-VO2) thin film is in an insulating phase, exhibiting either high transmittance or low emission. When the temperature rises to the point where the W-VO2 layer undergoes a phase transition, the device forms a FP-cavity resonant absorption structure, exhibiting high absorption and high emission. When the temperature rises further to the point where the undoped VO2 layer undergoes a phase transition, the VO2 layer transforms into a metallic phase and generates strong infrared reflection, causing the device to re-enter a low emission state. This achieves a non-monotonic change in thermal emissivity with temperature, exhibiting a "low-high-low" pattern. The device simultaneously possesses significant variations in transmittance, absorptivity, and reflectivity, enabling global dynamic control of the three optical coefficients of infrared transmission, absorption, and reflection, thus overcoming the limitation of the monotonic change in radiated power with temperature in traditional thermal emission devices.

[0009] Furthermore, the percentage of W atoms in the first W-doped VO2 layer and the second W-doped VO2 layer is independently selected from 0.01-5 at%, corresponding to a phase transition temperature range of 68°C to -24°C for the VO2 thin film.

[0010] Furthermore, the material of the dielectric layer is selected from HfO2, Al2O3, CuO, Cr2O3, Ag2O, TiO2, NiO, SiO2, and GeO2.

[0011] Furthermore, the substrate is selected from one of Si, Ge, Al, Ag, Au, W, diamond, CaF2, BaF2, ITO, AZO, and FTO.

[0012] Furthermore, the thicknesses of the first W-doped VO2 layer and the second W-doped VO2 layer are independently selected from 10-1000 nm.

[0013] Furthermore, the thickness of the dielectric layer is 10nm-5μm.

[0014] Furthermore, the thickness of the VO2 layer is 10-1000 nm.

[0015] The second aspect of this invention provides a method for fabricating the temperature-confined dynamic thermal radiation control device described in the first aspect, comprising the following steps: S1. Provide a polishing substrate; S2. The substrate is placed in a magnetron sputtering chamber and a first W-doped VO2 layer, a dielectric layer, a VO2 layer and a second W-doped VO2 layer are deposited sequentially.

[0016] Furthermore, S1 also includes substrate cleaning and drying steps.

[0017] Furthermore, in S2, the deposition of the first W-doped VO2 layer and the second W-doped VO2 layer is performed using a W-doped V metal target. The VO2 layer is deposited using a V metal target; the dielectric layer is deposited using a Hf, Al, Cu, Cr, Ag, Ti, Ni, Si, or Ge target.

[0018] The beneficial effects of this invention are: The present invention constructs a VO2-based multilayer thin film structure with different phase transition dynamics characteristics to achieve global dynamic control of infrared transmission, absorption and reflection. It can transform the infrared radiation behavior of traditional thermal emission devices that changes monotonically with temperature into temperature-confined non-monotonic radiation emission, so that the thermal emissivity exhibits a three-state change law of "low-high-low" with temperature, thus constructing a "tropical pass filter" in the temperature domain.

[0019] This invention can achieve coordinated regulation of infrared transmission, absorption and reflection by adjusting the thickness of W-VO2, VO2 and dielectric layers, and can obtain high absorptivity, transmittance and reflectivity variations; selective thermal emission under different target temperature windows can be achieved by adjusting the W doping concentration, VO2 phase transition temperature and phase transition hysteresis width.

[0020] The device of this invention can significantly enhance infrared thermal radiation within a specific temperature range, while suppressing infrared thermal radiation in low and high temperature ranges. Therefore, it can be used for temperature-limited infrared displays, dynamic thermal camouflage, thermal information encryption, and multi-level information encoding. Attached Figure Description

[0021] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the temperature-limited thermal radiation dynamic control device of the present invention; Figure 2 These are simulated spectra of the transmittance, reflectance, and absorptivity of the device in Embodiment 1 of the present invention at different temperatures; Figure 3 These are the spectra of transmittance, reflectance, and absorptance of the device in Embodiment 1 of the present invention at different temperatures. Detailed Implementation

[0023] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] This embodiment relates to a temperature-confined thermal radiation dynamic control device, including a substrate and a temperature-confined thermal emission structure disposed on the substrate. The thermal emission structure achieves dynamic control of three optical coefficients: infrared transmission, absorption, and reflection through a VO2-based multilayer thin film. The thermal emission structure is sequentially disposed with a first W-doped VO2 layer, a dielectric layer, a VO2 layer, and a second W-doped VO2 layer along the direction away from the substrate.

[0025] This embodiment constructs a VO2-based multilayer thin film structure with different phase transition kinetics in the vertical direction. Because the W-doped VO2 (W-VO2) layer and the VO2 layer have different optical responses at different temperatures, reference... Figure 1 At low temperatures, the VO2-based (VO2 / W-VO2) films are in an insulating phase, exhibiting either high transmittance or low emission. When the temperature rises to the point where the W-VO2 layer undergoes a phase transition, the device forms a FP-cavity resonant absorption structure, exhibiting both high absorption and high emission. When the temperature rises further to the point where the undoped VO2 layer undergoes a phase transition, the VO2 layer transforms into a metallic phase and generates strong infrared reflection, causing the device to re-enter a low emission state. This results in a non-monotonic change in thermal emissivity with temperature, exhibiting a "low-high-low" pattern. The device simultaneously possesses significant variations in transmittance, absorptivity, and reflectivity, enabling global dynamic control of the three optical coefficients of infrared transmission, absorption, and reflection. This overcomes the limitation of traditional thermal emission devices where radiated power changes monotonically with temperature.

[0026] In a preferred embodiment, the atomic percentage of W in the first W-doped VO2 layer and the second W-doped VO2 layer is independently selected from 0.01-5 at%, corresponding to a phase transition temperature range of 68°C to -24°C for the VO2 thin film.

[0027] In a preferred embodiment, the material of the dielectric layer is selected from HfO2, Al2O3, CuO, Cr2O3, Ag2O, TiO2, NiO, SiO2, and GeO2; the substrate is selected from Si, Ge, Al, Ag, Au, W, diamond, CaF2, BaF2, ITO, AZO, and FTO.

[0028] In a preferred embodiment, the thicknesses of the first W-doped VO2 layer and the second W-doped VO2 layer are independently selected from 10-1000 nm; the thickness of the dielectric layer is 10 nm-5 μm; and the thickness of the VO2 layer is 10-1000 nm.

[0029] Another embodiment provides a method for fabricating the temperature-confined thermal radiation dynamic control device described in the above embodiments, comprising the following steps: S1. Provide a polishing substrate; S2. The substrate is placed in a magnetron sputtering chamber and a first W-doped VO2 layer, a dielectric layer, a VO2 layer and a second W-doped VO2 layer are deposited sequentially.

[0030] In a preferred embodiment, S1 further includes a substrate cleaning and drying step; in S2, the deposition of the first W-doped VO2 layer and the second W-doped VO2 layer uses a W-doped V metal target; the deposition of the VO2 layer uses a V metal target; and the deposition of the dielectric layer uses a Hf, Al, Cu, Cr, Ag, Ti, Ni, Si or Ge target.

[0031] Example 1 This embodiment relates to a method for fabricating a temperature-confined thermal radiation dynamic control device, comprising the following steps: (1) Select a double-sided polished Si substrate, clean it three times with anhydrous ethanol / acetone, rinse it with ultrapure water, and finally dry it with nitrogen gas before placing it in a magnetron sputtering chamber to prepare for film deposition.

[0032] (2) Deposition of the bottom W-VO2 layer: Using a DC power supply, a W-doped V metal target was used to deposit a W-VO2 thin film under the following conditions: duty cycle of 1:80, substrate temperature of 25℃, sputtering pressure of 0.9Pa, oxygen-argon ratio of 3.6 / 81sccm, and power of 200W. The film thickness was 160nm and the atomic percentage of W was 0.03at.

[0033] (3) Deposition of intermediate medium HfO2 layer: Using DC power supply and metal Hf target, HfO2 thin film was deposited under the conditions of power of 200W, substrate temperature of 200℃, sputtering pressure of 0.6Pa and oxygen-argon ratio of 6.0 / 81sccm. The film thickness was 1300nm.

[0034] (4) VO2 layer deposition: Using a DC power supply and a pure V metal target, a VO2 thin film was deposited under the following conditions: duty cycle of 1:80, substrate temperature of 500℃, sputtering pressure of 0.9Pa, oxygen-argon ratio of 3.0 / 81sccm, and power of 200W. The film thickness was 260nm.

[0035] (5) Deposition of the top W-VO2 layer: Using a DC power supply and a W-doped V metal target, a W-VO2 thin film was deposited under the following conditions: duty cycle of 1:80, substrate temperature of 25℃, sputtering pressure of 0.9 Pa, oxygen-argon ratio of 3.6 / 81 sccm, and power of 200 W. The film thickness was 25 nm, and the atomic percentage of W was 0.03 at%; (6) Open the chamber and take out the sample to obtain the infrared band thermal radiation dynamic control device.

[0036] Figure 2 To simulate the transmittance, reflectance, and absorptance spectra of the device structure in this embodiment at different temperatures, Figure 3 The images show the transmittance, reflectance, and absorptance spectra of the device obtained in this embodiment at different temperatures. This verifies that the structure can achieve a wide range of emissivity from low to high temperatures. Specifically, the device transmittance reaches a maximum of 0.62 at low temperatures, the absorptance reaches a maximum of 0.93 at medium temperatures, and the reflectance reaches a maximum of 0.7 at high temperatures.

[0037] Comparative Example 1 The difference between this comparative example and Example 1 is that step (4) is omitted, while other steps and parameters remain unchanged. The device prepared is unable to achieve the third state of high reflectivity because there is no second VO2 layer deposition. It only has a transmittance of 0.75 at low temperature and an absorptivity of 0.95 at medium temperature.

[0038] In summary, the thermal radiation dynamic control device of this invention constructs a VO2-based multilayer thin film structure with different phase transition kinetics, achieving global dynamic control of infrared transmission, absorption, and reflection. It transforms the monotonic infrared radiation behavior of traditional thermal emission devices into temperature-confined non-monotonic radiation emission, causing the thermal emissivity to exhibit a three-state variation law of "low-high-low" with temperature, thus constructing a "heat pass filter" in the temperature domain. By adjusting the thickness of W-VO2, VO2, and the dielectric layer, coordinated regulation of infrared transmission, absorption, and reflection can be achieved, resulting in high variations in absorptivity, transmittance, and reflectivity. Selective thermal emission under different target temperature windows can be achieved by adjusting the W doping concentration, VO2 phase transition temperature, and phase transition hysteresis width. The device can significantly enhance infrared thermal radiation within a specific temperature range while suppressing it in low and high temperature ranges, thus making it suitable for temperature-confined infrared displays, dynamic thermal camouflage, thermal information encryption, and multi-level information encoding.

[0039] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A temperature-limited thermal radiation dynamic control device, characterized in that, The invention includes a substrate and a temperature-confined thermal emission structure disposed on the substrate. The thermal emission structure achieves dynamic control of the three optical coefficients of infrared transmission, absorption and reflection through a VO2-based multilayer thin film. The thermal emission structure is sequentially arranged with a first W-doped VO2 layer, a dielectric layer, a VO2 layer, and a second W-doped VO2 layer along the direction away from the substrate.

2. The temperature-confined thermal radiation dynamic control device as described in claim 1, characterized in that, The percentage of W atoms in the first W-doped VO2 layer and the second W-doped VO2 layer is independently selected from 0.01-5 at.

3. The temperature-confined dynamic thermal radiation control device as described in claim 1, characterized in that, The material of the dielectric layer is selected from HfO2, Al2O3, CuO, Cr2O3, Ag2O, TiO2, NiO, SiO2, and GeO2.

4. The temperature-confined thermal radiation dynamic control device as described in claim 1, characterized in that, The substrate is selected from one of Si, Ge, Al, Ag, Au, W, diamond, CaF2, BaF2, ITO, AZO, and FTO.

5. The temperature-confined dynamic thermal radiation control device as described in claim 1, characterized in that, The thicknesses of the first W-doped VO2 layer and the second W-doped VO2 layer are independently selected from 10-1000 nm.

6. The temperature-confined thermal radiation dynamic control device as described in claim 1, characterized in that, The thickness of the dielectric layer is 10nm-5μm.

7. The temperature-confined dynamic thermal radiation control device as described in claim 1, characterized in that, The thickness of the VO2 layer is 10-1000 nm.

8. A method for preparing a temperature-confined dynamic thermal radiation control device according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Provide a polishing substrate; S2. The substrate is placed in a magnetron sputtering chamber and a first W-doped VO2 layer, a dielectric layer, a VO2 layer and a second W-doped VO2 layer are deposited sequentially.

9. The method for fabricating the temperature-confined thermal radiation dynamic control device as described in claim 8, characterized in that, S1 also includes substrate cleaning and drying steps.

10. The method for fabricating the temperature-confined dynamic thermal radiation control device as described in claim 8, characterized in that, In S2, the deposition of the first W-doped VO2 layer and the second W-doped VO2 layer is performed using a W-doped V metal target. The VO2 layer is deposited using a V metal target; the dielectric layer is deposited using a Hf, Al, Cu, Cr, Ag, Ti, Ni, Si, or Ge target.

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