Stealth film based on phase change characteristics of vanadium dioxide and preparation method thereof

Abstract

The present application discloses a stealth film based on the phase change characteristics of vanadium dioxide and its preparation method, aiming to solve the technical problems of narrow absorption spectrum range, difficult regulation, poor environmental adaptability and poor binding performance of existing stealth films. The present application uses VO(OC3H7)3 and deionized water as precursors to deposit vanadium oxide; annealing in an annealing furnace to obtain vanadium dioxide nanoparticles; placing the substrate material deposited with vanadium dioxide nanoparticles into an atomic layer deposition chamber to deposit a dielectric layer; then depositing an upper vanadium oxide film, and finally preparing a series of "VO2 nanoparticles / dielectric layer / VO2 film" dynamic MIM ternary structure intelligent stealth films with adjustable structural parameters. The preparation conditions of the present invention are controllable, the stealth spectrum range has flexible regulation, and the full coating effect of the substrate material can be achieved, avoiding the problem of poor adhesion between the coating method and the substrate material. The stealth performance is reversible, and it has broad application prospects in the field of intelligent stealth in life and national defense.

Description

Technical Field

[0001] The present application relates to the technical field of stealth material preparation, and in particular to a stealth film based on the phase change characteristics of vanadium dioxide and a preparation method thereof. Background Art

[0002] Stealth materials, also known as electromagnetic wave super-absorption materials, have important application prospects in the fields of stealth cloaks, stealth fighters, and other civil and national defense security fields because they can achieve near-perfect absorption of electromagnetic waves. The absorption of light or electromagnetic waves is an intrinsic property of matter, but how to achieve near-perfect absorption close to 100% has always been a research hotspot that scientists have paid extensive attention to. In 2008, Landy's research team successfully prepared a metamaterial absorber for the first time in the experiment, that is, constructing a metal / dielectric layer / metal (MIM) ternary structure, with the top layer being metal nanoparticles, and the middle and bottom layers consisting of continuous dielectric layers and metal layers, relying on the plasmon coupling effect of the upper and lower metal layers to enhance the material's ability to absorb light. The carrier of plasmons is generally a precious metal, essentially because a large number of free carriers in precious metals make the real part of their dielectric function negative. Further, by changing the arrangement of metal particles and the carrier concentration inside the metal, the electromagnetic wave absorption band can be adjusted, which can be applied to the stealth fields of different bands such as visible waves, infrared waves, radar waves, and terahertz waves. However, such stealth materials involve precious metals and are expensive to prepare.

[0003] On the other hand, vanadium dioxide is an intelligent phase change material in a strongly correlated electronic system. Through different external environmental stimuli, such as temperature regulation, photon irradiation, electric field, electrochemistry, stress, magnetic field, etc., it can induce a reversible metal-insulator phase transition. At the same time as the phase transition, the internal carrier concentration changes dynamically, making it widely used in many fields, including smart windows, laser protection, microbolometers, uncooled infrared detectors, optical switches, stealth, electrical switches, and thermal detectors. In terms of stealth materials, there are coating materials prepared using vanadium dioxide that can achieve stealth effects within a certain band; there are also flexible materials made of vanadium dioxide as raw materials, such as patent document CN107418063A discloses a flexible vanadium dioxide sheet for infrared stealth and its preparation method, which is a flexible sheet extruded from a mixture of ethylene propylene diene rubber, vanadium dioxide powder and antioxidant.

[0004] The information disclosed in this background technology section is only used to deepen the understanding of the background technology of the present disclosure, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art known to those skilled in the art. Summary of the invention

[0005] Through research, the inventors found that the existing vanadium dioxide-based stealth materials still have some problems: on the one hand, the absorption spectrum range is narrow, the regulation is difficult and the ability to adapt to the environment is poor; on the other hand, the stealth material obtained by coating has poor adhesion to the substrate, which limits its application field.

[0006] In view of at least one of the above technical problems, the present disclosure provides a method for preparing an intelligent stealth film based on the phase change characteristics of vanadium dioxide. On the one hand, the phase change and adjustable internal carrier concentration characteristics of vanadium dioxide are utilized to creatively propose it as a substitute for the metal layer of the MIM structure to obtain an intelligent stealth film with adjustable wide spectrum characteristics and environmental adaptability; on the other hand, the three-dimensional mode of atomic layer deposition is used to directly deposit a thin film of MIM ternary structure on the substrate to avoid the problem of poor adhesion of the coating material. Specifically, the essence of surface plasmons is an electromagnetic wave propagating along the surface formed by the coupling of free electrons that collectively oscillate between light and the surface of matter, and vanadium dioxide belongs to a strongly correlated electronic system. When stimulated by the outside world, the strong Coulomb interaction between electrons will drive the collective motion of electrons, and the reversible phase transition from the insulating state to the metallic state will cause the carrier concentration to increase sharply. At the same time, it can be doped with atoms (V 1-x M x O2), oxygen regulation (VO 2±x ) and other simple technical means to manipulate its internal carrier concentration, and utilize the phase change and adjustable internal carrier concentration characteristics of vanadium dioxide to replace precious metals as plasmon materials, thereby constructing a new type of dynamic MIM intelligent stealth thin film material, further expanding the application field of stealth materials; at the same time, compared with stealth coatings and other materials, the application of thin films avoids a series of coating problems such as poor adhesion between coatings and substrates.

[0007] According to one aspect of the present disclosure, a stealth film based on the phase change characteristics of vanadium dioxide is provided, comprising a substrate layer and a dynamic MIM ternary structure deposited thereon, wherein the dynamic MIM ternary structure is composed of vanadium dioxide nanoparticles, a dielectric layer, and a vanadium oxide film layer; the dielectric layer is an aluminum oxide, zinc oxide or titanium oxide dielectric layer; the vanadium oxide film layer is a metal atom doped V 1-x M x O2, oxygen vacancy-rich VO 2-x or oxygen-enriched VO 2+x of vanadium dioxide thin film.

[0008] In some embodiments of the present disclosure, the vanadium dioxide nanoparticles are prepared by the following method: using VO(OC3H7)3 and water as precursors to atomically layer deposit a vanadium oxide film on the substrate, and then annealing to obtain vanadium dioxide nanoparticles with a certain morphology and microstructure.

[0009] By changing the thickness of the atomic layer deposited vanadium oxide film, annealing conditions (including annealing time, annealing temperature, annealing atmosphere, annealing pressure, etc.) and element doping in the vanadium oxide film, a series of vanadium dioxide nanoparticles with different sizes, morphologies and distributions are obtained, and the vanadium dioxide nanoparticles are further artificially patterned using non-photolithography laser direct writing.

[0010] In some embodiments of the present disclosure, the dielectric layer is formed by atomic layer deposition using (CH3)3Al, (C2H5)2Zn or (C3H7O)4Ti, and deionized water (H2O) as precursors.

[0011] In some embodiments of the present disclosure, the base layer is made of sapphire or quartz.

[0012] According to another aspect of the present disclosure, a method for preparing the stealth film is provided, comprising the following steps:

[0013] (1) Using VO(OC3H7)3 and water as precursors, atomic layer deposition is performed on the surface of a substrate material to obtain a vanadium oxide base film, and then annealing is performed to form vanadium dioxide nanoparticles attached to the surface of the substrate material through the vanadium oxide base film;

[0014] (2) performing atomic layer deposition on the surface of the vanadium dioxide nanoparticles to form an aluminum oxide, zinc oxide or titanium oxide dielectric layer;

[0015] (3) Then, metal atoms are deposited on the dielectric layer to form V 1-x M x O2, oxygen vacancy-rich VO 2-x or oxygen-enriched VO 2+x of vanadium oxide thin films.

[0016] In some embodiments of the present disclosure, in step (1), the number of vanadium oxide base film deposition cycles is 2000 to 8000, and the thickness is 24 to 96 nm.

[0017] In some embodiments of the present disclosure, in the step (1), annealing is performed at a temperature of 400 to 600° C., an annealing time of 1 to 4 hours, an annealing atmosphere of argon, a flow rate of 45 to 55 sccm, a furnace pressure of 3.0 to 4.0 mbar, and vanadium dioxide nanoparticles with a radius of 50 to 300 nm are obtained.

[0018] In some embodiments of the present disclosure, in step (2), (CH3)3Al, (C2H5)2Zn or (C3H7O)4Ti and water are used as precursors to deposit an aluminum oxide, zinc oxide or titanium oxide dielectric layer with a thickness of 30 to 90 nm.

[0019] In some embodiments of the present disclosure, in step (3), the metal atom is doped with V 1-x M x The vanadium oxide film of O2 is achieved by introducing at least one of metal organic sources aluminum, zinc or titanium during the deposition process of the vanadium oxide film.

[0020] In some embodiments of the present disclosure, in step (3), the oxygen vacancy-rich VO 2-x The vanadium oxide film is obtained by annealing the vanadium oxide film in a 3% H2 / Ar mixed gas in a reducing atmosphere; oxygen-enriched VO 2+x The vanadium oxide film is obtained by annealing the vanadium oxide film in a 3% O2 / Ar mixed gas in an oxidizing atmosphere.

[0021] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0022] 1. The applicable spectral range of the ternary structure film of "VO2 nanoparticles / dielectric layer / VO2 film" is flexible and controllable. By adjusting the size and distribution of VO2 nanoparticles, the type and thickness of the dielectric layer, the metal element doping in the VO2 film layer, the oxygen content change, etc., the electromagnetic wave absorption response band of the ternary structure of VO2 nanoparticles / dielectric layer / VO2 film can be changed, and an intelligent stealth film with a wider absorption spectrum can be obtained. The phase change of vanadium dioxide can occur within picoseconds and the process is reversible. Therefore, the intelligent stealth film based on the phase change structure of vanadium dioxide has ultra-fast and reversible stealth characteristics.

[0023] 2. By utilizing the metal-insulator reversible phase transition of vanadium dioxide, the constructed ternary structure intelligent stealth film can be induced to intelligently switch between stealth and non-stealth states through external stimuli according to different application scenarios, and has good environmental adaptability.

[0024] 3. The thin film material preparation method used is atomic layer deposition, which can achieve full coverage of the substrate material; the intelligent stealth film is directly deposited on the substrate material using atomic layer deposition, avoiding the problem of poor adhesion between the coating material and the substrate.

[0025] 4. The preparation conditions of this application are controllable, the stealth spectrum range is flexibly adjustable, and the full coverage effect of the base material can be achieved, avoiding the problem of poor adhesion between the coating method and the base material, and the stealth performance is reversible. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a flow chart for preparing the “VO2 nanoparticles / dielectric layer / VO2 film” intelligent stealth film in one embodiment of the present application.

[0027] Figure 2Surface and cross-sectional SEM images of an atomic layer deposited vanadium oxide film (Figure a) and vanadium dioxide nanoparticles (Figure b) in one embodiment of the present application.

[0028] Figure 3 This is a diagram showing the change in infrared transmittance caused by the phase change of vanadium dioxide in one embodiment of the present application.

[0029] Figure 4 This is a diagram of the application model of the “VO2 nanoparticles / dielectric layer / VO2 film” intelligent stealth film in one embodiment of the present application. DETAILED DESCRIPTION

[0030] The atomic layer deposition equipment involved in the following embodiments is Picosun-R200, the scanning electron microscope is JSM-7001F, the atomic force microscope is Bruker VT-1000, the Raman-induced spectrometer is Nanofinder 30, the transmission electron microscope is JEM-2100, the X-ray diffractometer is Beijing Puxi XD-3, the optical Dewar is Oxford Optistat DN-V2, the visible-near infrared spectrometer is PerkinElmer Lambda 950, and the Hall effect tester is Lake shore; other instruments and equipment involved are conventional instruments and equipment unless otherwise specified; the industrial raw materials involved are conventional industrial raw materials available on the market unless otherwise specified; the experiments, detection, testing, preparation methods, etc. involved are conventional methods used in the art unless otherwise specified.

[0031] In order to better understand the technical solution of the present application, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0032] Embodiment 1

[0033] This example discloses a method for preparing an intelligent stealth film based on the phase change characteristics of vanadium dioxide, comprising the following steps (see Figure 1 ):

[0034] (1) A sapphire substrate was placed in the chamber of an atomic layer deposition device, the chamber temperature was set to 150°C, the source temperature was set to 80°C, tri(isopropanol)oxyvanadium (VO(OC3H7)3, VTIP) and deionized water (H2O) were used as precursors, and the number of atomic layer deposition cycles was set to 2000 (about 24 nm) to obtain a vanadium oxide film; the obtained sample was placed in an annealing furnace and annealed at 400°C for 1 hour. During the annealing process, inert gas argon was introduced with a flow rate set to 50 sccm. The pressure in the tubular furnace was maintained at about 3.5 mbar by adjusting the mechanical pump valve to obtain vanadium dioxide nanoparticles;

[0035] (2) placing the obtained substrate material deposited with vanadium dioxide nanoparticles into an atomic layer deposition chamber, using trimethylaluminum ((CH3)3Al, TMA) and deionized water (H2O) as precursors, setting the number of atomic layer deposition cycles to 100, and depositing a 90 nm aluminum oxide dielectric layer;

[0036] (3) Then, an aluminum-doped vanadium oxide film is deposited on the sample obtained in the previous step. The deposition cycle ratio is set to V:Al=750, and the number of outer cycles is set to 8, thereby preparing a "VO2 nanoparticles / Al2O3 dielectric layer / Al-doped VO2" intelligent stealth film. The application principle model can be found in Figure 4 .

[0037] Embodiment 2

[0038] This example discloses a method for preparing an intelligent stealth film based on the phase change characteristics of vanadium dioxide, comprising the following steps (see Figure 1 ):

[0039] (1) A quartz substrate was placed in the chamber of an atomic layer deposition device, the chamber temperature was set to 150°C, the source temperature was set to 80°C, tri(isopropanol)oxyvanadium (VO(OC3H7)3, VTIP) and deionized water (H2O) were used as precursors, and the number of atomic layer deposition cycles was set to 4000 (about 48 nm) to obtain a vanadium oxide film; the obtained sample was placed in an annealing furnace and annealed at 500°C for 2 h. During the annealing process, inert gas argon was introduced with a flow rate set to 50 sccm. The pressure in the tubular furnace was maintained at about 3.5 mbar by adjusting the mechanical pump valve to obtain vanadium dioxide nanoparticles;

[0040] (2) The substrate material with vanadium dioxide nanoparticles deposited in the previous step was placed in an atomic layer deposition chamber, diethyl zinc ((C2H5)2Zn, DEZ) and deionized water (H2O) were used as precursors, the atomic layer deposition cycle number was set to 400, and a 60 nm zinc oxide dielectric layer was deposited;

[0041] (3) Then, a zinc-doped vanadium oxide film is deposited on the sample obtained in the previous step. The deposition cycle ratio is set to V:Zn=120 for the inner cycle and 50 for the outer cycle. The “VO2 nanoparticles / ZnO dielectric layer / Zn-doped VO2” smart stealth film is prepared. The application principle model is shown in Figure 4 .

[0042] Embodiment 3

[0043] This example discloses a method for preparing an intelligent stealth film based on the phase change characteristics of vanadium dioxide, comprising the following steps (see Figure 1 ):

[0044] (1) Place the sapphire substrate in the chamber of the atomic layer deposition equipment, set the chamber temperature to 150°C, the source temperature to 80°C, use tri(isopropanol)oxyvanadium (VO(OC3H7)3, VTIP) and deionized water (H2O) as precursors, set the number of atomic layer deposition cycles to 6000 (about 72nm) to obtain a vanadium oxide film; see Figure 2 (a), the obtained film has uniform thickness, smooth surface, and is tightly bonded to the substrate material; the obtained sample is placed in an annealing furnace and annealed at 500°C for 3 hours. During the annealing process, inert gas argon is introduced with a flow rate of 50 sccm. The pressure in the tube furnace is maintained at about 3.5 mbar by adjusting the valve of the mechanical pump to obtain vanadium dioxide nanoparticles; see Figure 2 (b), radius 50-300 nm;

[0045] (2) The substrate material with vanadium dioxide nanoparticles deposited thereon obtained in the previous step was placed in an atomic layer deposition chamber, titanium tetraisopropoxide ((C3H7O)4Ti, TTIP) and deionized water (H2O) were used as precursors, the atomic layer deposition cycle number was set to 1200, and a 30 nm titanium oxide dielectric layer was deposited;

[0046] (3) Then, a zinc-doped vanadium oxide film is deposited on the sample obtained in the previous step. The deposition cycle ratio is set to V:Zn=240, and the number of outer cycles is set to 25. The "VO2 nanoparticles / TiO2 dielectric layer / Zn-doped VO2" smart stealth film is prepared. The application principle model can be found in Figure 4 .

[0047] Embodiment 4

[0048] This example discloses a method for preparing an intelligent stealth film based on the phase change characteristics of vanadium dioxide, comprising the following steps (see Figure 1 ):

[0049] (1) A quartz substrate was placed in the chamber of an atomic layer deposition device, the chamber temperature was set to 150°C, the source temperature was set to 80°C, tri(isopropanol)oxyvanadium (VO(OC3H7)3, VTIP) and deionized water (H2O) were used as precursors, and the number of atomic layer deposition cycles was set to 7000 (about 84 nm) to obtain a vanadium oxide film; the obtained sample was placed in an annealing furnace and annealed at 500°C for 4 hours. During the annealing process, inert gas argon was introduced with a flow rate set to 50 sccm. The pressure in the tubular furnace was maintained at about 3.5 mbar by adjusting the mechanical pump valve to obtain vanadium dioxide nanoparticles;

[0050] (2) The substrate material with vanadium dioxide nanoparticles deposited thereon obtained in the previous step was placed in an atomic layer deposition chamber, titanium tetraisopropoxide ((C3H7O)4Ti, TTIP) and deionized water (H2O) were used as precursors, the number of atomic layer deposition cycles was set to 2000, and a 50 nm titanium oxide dielectric layer was deposited;

[0051] (3) Then, a titanium-doped vanadium oxide film is deposited on the sample obtained in the previous step. The deposition cycle ratio is set to V:Ti=20 for the inner cycle and 300 for the outer cycle. The “VO2 nanoparticles / TiO2 dielectric layer / Ti-doped VO2” smart stealth film is prepared. The application principle model is shown in Figure 4 .

[0052] Embodiment 5

[0053] This example discloses a method for preparing an intelligent stealth film based on the phase change characteristics of vanadium dioxide, comprising the following steps (see Figure 1 ):

[0054] (1) Place a sapphire substrate in the chamber of an atomic layer deposition device, set the chamber temperature to 150°C, set the source temperature to 80°C, use tri(isopropanol)oxyvanadium (VO(OC3H7)3, VTIP) and deionized water (H2O) as precursors, set the atomic layer deposition cycle number to 8000 (about 96 nm) to obtain a vanadium oxide film; place the sample obtained in the previous step in an annealing furnace and anneal at 600°C for 2 hours. During the annealing process, introduce inert gas argon at a flow rate of 50 sccm. By adjusting the mechanical pump valve, the pressure in the tubular furnace is maintained at about 3.5 mbar to obtain vanadium dioxide nanoparticles;

[0055] (2) The substrate material deposited with vanadium dioxide nanoparticles obtained in the previous step was placed in an atomic layer deposition chamber, diethyl zinc ((C2H5)2Zn, DEZ) and deionized water (H2O) were used as precursors, the number of atomic layer deposition cycles was set to 500, and a 75 nm zinc oxide dielectric layer was deposited;

[0056] (3) Then, a titanium-doped vanadium oxide film is deposited on the sample obtained in the previous step. The deposition cycle ratio is set to V:Ti=80 for the inner cycle and 75 for the outer cycle. The “VO2 nanoparticles / ZnO dielectric layer / Ti-doped VO2” smart stealth film is prepared. The application principle model is shown in Figure 4 .

[0057] Embodiment 6

[0058] This example discloses a method for preparing an intelligent stealth film based on the phase change characteristics of vanadium dioxide, comprising the following steps (see Figure 1 ):

[0059] (1) A sapphire substrate was placed in the chamber of an atomic layer deposition device, the chamber temperature was set to 150°C, the source temperature was set to 80°C, tri(isopropanol)oxyvanadium (VO(OC3H7)3, VTIP) and deionized water (H2O) were used as precursors, and the number of atomic layer deposition cycles was set to 5000 (about 60 nm) to obtain a vanadium oxide film; the obtained sample was placed in an annealing furnace and annealed at 400°C for 4 hours. During the annealing process, inert gas argon was introduced with a flow rate set to 50 sccm. The pressure in the tubular furnace was maintained at about 3.5 mbar by adjusting the mechanical pump valve to obtain vanadium dioxide nanoparticles;

[0060] (2) Place the substrate material deposited with vanadium dioxide nanoparticles obtained in the previous step into an atomic layer deposition chamber, use trimethylaluminum ((CH3)3Al, TMA) and deionized water (H2O) as precursors, set the atomic layer deposition cycle number to 50, and deposit a 45nm aluminum oxide dielectric layer;

[0061] (3) Then, a titanium-doped vanadium oxide film is deposited on the sample obtained in the previous step. The deposition cycle ratio is set to V:Ti=40 for the inner cycle and 150 for the outer cycle. The “VO2 nanoparticles / Al2O3 dielectric layer / Ti-doped VO2” smart stealth film is prepared. The application principle model is shown in Figure 4 .

[0062] Embodiment 7

[0063] This example discloses a method for preparing an intelligent stealth film based on the phase change characteristics of vanadium dioxide, comprising the following steps (see Figure 1 ):

[0064] (1) A quartz substrate was placed in the chamber of an atomic layer deposition device, the chamber temperature was set to 150°C, the source temperature was set to 80°C, tri(isopropanol)oxyvanadium (VO(OC3H7)3, VTIP) and deionized water (H2O) were used as precursors, and the number of atomic layer deposition cycles was set to 6000 (about 72 nm) to obtain a vanadium oxide film; the obtained sample was placed in an annealing furnace and annealed at 600°C for 4 hours. During the annealing process, inert gas argon was introduced with a flow rate set to 50 sccm. The pressure in the tubular furnace was maintained at about 3.5 mbar by adjusting the mechanical pump valve to obtain vanadium dioxide nanoparticles;

[0065] (2) The substrate material deposited with vanadium dioxide nanoparticles obtained in the previous step was placed in an atomic layer deposition chamber, trimethylaluminum ((CH3)3Al, TMA) and deionized water (H2O) were used as precursors, the atomic layer deposition cycle number was set to 60, and a 54 nm aluminum oxide dielectric layer was deposited;

[0066] (3) Then, a vanadium oxide film is deposited on the sample obtained in the previous step, and the number of cycles is set to 6000 (about 72 nm). The film is annealed in a nitrogen atmosphere to prepare a "VO2 nanoparticles / Al2O3 dielectric layer / VO2" smart stealth film. The application principle model can be found in Figure 4 .

[0067] Embodiment 8

[0068] This example discloses a method for preparing an intelligent stealth film based on the phase change characteristics of vanadium dioxide, comprising the following steps (see Figure 1 ):

[0069] (1) A sapphire substrate was placed in the chamber of an atomic layer deposition device, the chamber temperature was set to 150°C, the source temperature was set to 80°C, tri(isopropanol)oxyvanadium (VO(OC3H7)3, VTIP) and deionized water (H2O) were used as precursors, and the number of atomic layer deposition cycles was set to 5000 (about 60 nm) to obtain a vanadium oxide film; the obtained sample was placed in an annealing furnace and annealed at 500°C for 2 h. During the annealing process, inert gas argon was introduced at a flow rate of 50 sccm. The pressure in the tubular furnace was maintained at about 3.5 mbar by adjusting the mechanical pump valve to obtain vanadium dioxide nanoparticles;

[0070] (2) The substrate material deposited with vanadium dioxide nanoparticles obtained in the previous step was placed in an atomic layer deposition chamber, diethyl zinc ((C2H5)2Zn, DEZ) and deionized water (H2O) were used as precursors, the number of atomic layer deposition cycles was set to 300, and a 45 nm zinc oxide dielectric layer was deposited;

[0071] (3) Then, a vanadium oxide film was deposited on the sample obtained in the previous step, and the number of cycles was set to 6000 (about 72 nm). The film was annealed in a 3% H2 / Ar reducing atmosphere to prepare a "VO2 nanoparticle / ZnO dielectric layer / VO 2-x "Intelligent stealth film, its application principle model can be found in Figure 4 .

[0072] Embodiment 9

[0073] This example discloses a method for preparing an intelligent stealth film based on the phase change characteristics of vanadium dioxide, comprising the following steps (see Figure 1 ):

[0074] (1) Place a sapphire substrate in the chamber of an atomic layer deposition device, set the chamber temperature to 150°C, set the source temperature to 80°C, use tri(isopropanol)oxyvanadium (VO(OC3H7)3, VTIP) and deionized water (H2O) as precursors, set the atomic layer deposition cycle number to 6000 (about 72nm) to obtain a vanadium oxide film; place the sample obtained in the previous step in an annealing furnace and anneal at 600°C for 3h. During the annealing process, introduce inert gas argon at a flow rate of 50sccm. The pressure in the tubular furnace is maintained at about 3.5mbar by adjusting the mechanical pump valve to obtain vanadium dioxide nanoparticles;

[0075] (3) The substrate material deposited with vanadium dioxide nanoparticles obtained in the previous step was placed in an atomic layer deposition chamber, titanium tetraisopropoxide ((C3H7O)4Ti, TTIP) and deionized water (H2O) were used as precursors, the atomic layer deposition cycle number was set to 3000, and a 75 nm titanium oxide dielectric layer was deposited;

[0076] (3) Then, a vanadium oxide film was deposited on the sample obtained in the previous step, and the number of cycles was set to 6000 (about 72 nm). The film was annealed in a 3% O2 / Ar oxidizing atmosphere to prepare a "VO2 nanoparticle / TiO2 dielectric layer / VO 2+x "Intelligent stealth film, its application principle model can be found in Figure 4 .

[0077] From the above analysis, it can be seen that based on the phase change characteristics of vanadium dioxide (see Figure 3 ) utilizes the reversible phase change characteristics of vanadium dioxide and the adjustability of the phase change process to obtain a non-coated dynamic MIM intelligent stealth film with wide spectrum characteristics and environmental adaptability, breaking the limitation that the traditional stealth materials have fixed wave-absorbing characteristics once they are successfully prepared. It provides new ideas for the application of vanadium dioxide phase change in the field of intelligent stealth and expands its application prospects in the fields of people's livelihood and national defense.

[0078] Although some preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0079] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the invention of the present application. Thus, if these modifications and variations to the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A stealth film based on the phase change characteristics of vanadium dioxide, comprising a substrate layer, characterized in that: It also includes a dynamic MIM ternary structure deposited on the substrate layer, the dynamic MIM ternary structure is composed of vanadium dioxide nanoparticles, a dielectric layer, and a vanadium oxide film layer; the stealth film is prepared by a method comprising the following steps: (1) Using VO(OC3H7)3 and water as precursors, atomic layer deposition is performed on the surface of the substrate to obtain a vanadium oxide base film, and then annealing is performed to form vanadium dioxide nanoparticles attached to the surface of the substrate with a certain morphology and microstructure; (2) performing atomic layer deposition on the surface of the vanadium dioxide nanoparticles using (CH3)3Al, (C2H5)2Zn or (C3H7O)4Ti and deionized water as precursors to form a dielectric layer of aluminum oxide, zinc oxide or titanium oxide; (3) Then, metal atoms are deposited on the dielectric layer to form V 1-x M x O2, oxygen vacancy-rich VO 2-x or oxygen-enriched VO 2+x of vanadium oxide thin film.

2. The stealth film according to claim 1, characterized in that: The base layer is made of sapphire or quartz.

3. The stealth film according to claim 1, characterized in that: In the step (1), the number of deposition cycles of the vanadium oxide base film is 2000 to 8000, and the thickness is 24 to 96 nm.

4. The stealth film according to claim 1, characterized in that: In the step (1), annealing is performed at a temperature of 400 to 600° C., an annealing time of 1 to 4 hours, an annealing atmosphere of argon, a flow rate of 45 to 55 sccm, a furnace pressure of 3.0 to 4.0 mbar, and vanadium dioxide nanoparticles with a radius of 50 to 300 nm are obtained.

5. The stealth film according to claim 1, characterized in that: In the step (2), (CH3)3Al, (C2H5)2Zn or (C3H7O)4Ti and water are used as precursors to deposit an aluminum oxide, zinc oxide or titanium oxide dielectric layer with a thickness of 30 to 90 nm.

6. The stealth film according to claim 1, characterized in that: In step (3), metal atoms are doped with V 1- x M x The vanadium oxide film layer of O2 is achieved by introducing at least one of metal organic sources of aluminum, zinc or titanium during the deposition process of the vanadium oxide film.

7. The stealth film according to claim 1, characterized in that: In step (3), the oxygen vacancy-rich VO 2-x The vanadium oxide film layer is obtained by annealing the vanadium oxide film in a 3% H2 / Ar mixed gas in a reducing atmosphere; oxygen-enriched VO 2+x The vanadium oxide film layer is obtained by annealing the vanadium oxide film in a 3% O2 / Ar mixed gas in an oxidizing atmosphere.

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