阅读说明：本技术 一种新型高透射率二氧化钒薄膜元件制备方案 (Preparation scheme of novel high-transmittance vanadium dioxide thin film element ) 是由 靳京城 张东平 范平 于 2018-09-13 设计创作，主要内容包括：本发明属于物理领域,具体涉及一种二氧化钒双层膜体系及其制备方法和应用。所述双层膜体系包括二氧化钒薄膜层和氧化硅渐变折射率材料薄膜层,所述渐变折射率材料薄膜和所述二氧化钒薄膜从下至上依次堆叠。所述二氧化钒双层膜体系利用了具有渐变折射率功能的材料氧化硅,使所述二氧化钒双层膜体系元件具有超宽波段、全立体角、偏振非敏感、高透过率光谱特性。(The invention belongs to the field of physics, and particularly relates to a vanadium dioxide double-layer film system, and a preparation method and application thereof. The double-layer film system comprises a vanadium dioxide thin film layer and a silicon oxide graded-index material thin film layer, wherein the graded-index material thin film and the vanadium dioxide thin film are sequentially stacked from bottom to top. The vanadium dioxide double-layer film system utilizes silicon oxide which is a material with a function of gradually changing refractive index, so that the vanadium dioxide double-layer film system element has the spectral characteristics of ultra-wide waveband, full solid angle, polarization insensitivity and high transmittance.)

1. The high-transmittance vanadium dioxide double-layer film system is characterized by comprising a graded-refractive-index material thin film layer and a vanadium dioxide thin film layer, wherein the vanadium dioxide thin film layer and the graded-refractive-index silicon oxide SiO_x(x is more than or equal to 0 and less than or equal to 2) the material film layers are stacked from bottom to top in sequence.

2. The high-transmittance vanadium dioxide bilayer film system according to claim 1, wherein the graded index material thin film layer is a silicon oxide thin film layer.

3. The preparation method of the high-transmittance vanadium dioxide double-layer film system is characterized in that the preparation method adopts a sputtering process to sequentially mix vanadium dioxide and a graded-index material SiO_xSputtering on the element substrate to form a structure of substrate/vanadium dioxide thin film layer/graded index material SiO_xThe vanadium dioxide double-layer film system of the thin film layer.

4. The method of claim 3, wherein the graded index material is SiO_x。

5. The preparation method of the novel high-transmittance vanadium dioxide thin film system according to claim 3, characterized in that the specific steps of the preparation method are as follows:

step one, theoretically designing and optimizing the spectral performance of a vanadium dioxide double-layer film system

Analyzing the influence trend and the change rule of the simulated sputtering process parameters on the performance of the graded refractive index material and the performance of the vanadium dioxide film respectively by adopting the existing film design software, thereby carrying out process preparation tolerance evaluation; the refractive index of the material film layer with the gradually-changing refractive index, which is beneficial to the preparation of an actual process, is changed and distributed within the range of 1.1-2.74, the advantage that the refractive index of the material with the gradually-changing refractive index of silicon oxide is continuously adjustable is utilized, and the vanadium dioxide double-layer film system is designed and optimized to have spectral performance of an ultra-wide band, a full solid angle, polarization insensitivity and high transmittance in an infrared band;

step two, preparing a vanadium dioxide thin film layer

Optimizing the deposition parameters of the sputtered vanadium dioxide film and comprehensively evaluating the characteristics of the vanadium dioxide film so as to obtain the proper deposition process parameters of the vanadium dioxide film on the glass substrate;

step three, sputtering the gradient refractive index material film layer

Comparing and analyzing the influence trend and change rule of sputtering process parameters on the performance of the silicon oxide material with the graded index, and performing complete optical performance characterization on the silicon oxide material with the graded index so as to obtain preparation implementation process parameters of a silicon oxide thin film layer of the material with the graded index;

and preparing the graded-index silicon oxide thin film layer on the vanadium dioxide thin film layer according to the deposition process parameters to obtain the vanadium dioxide double-layer film system with the structure of the graded-index material graded-index silicon oxide thin film layer/vanadium dioxide thin film layer.

6. The method for preparing a vanadium dioxide double-layer film system according to claim 5, wherein in the first step, innovative design application of characteristics of the silicon oxide graded index material in the vanadium dioxide film system is utilized.

7. The method for preparing a vanadium dioxide double-layer film system according to claim 5, wherein in the third step, the comprehensive evaluation of the characteristics of the vanadium dioxide film comprises:

1) characterizing the content of + 4-valent V in the film by XPS;

2) characterizing the crystal phase components by an X-ray diffractometer;

3) testing the surface shape change of the film surface by using an interferometer, and evaluating the stress characteristic;

4) VO testing by four-probe resistance measuring instrument₂Characteristic changes before and after phase change;

5) representing phase change characteristics such as phase change temperature, thermal hysteresis width, phase change amplitude and the like according to the thermal hysteresis loop;

6) measuring the spectral reflectance/transmittance before and after the phase change by using a spectrophotometer, and evaluating the spectral performance characteristics of the film;

7) testing and evaluating the aggregation density of the film by an ellipsometer;

8) the microstructure was characterized by field emission scanning electron microscopy.

8. The method according to claim 5, wherein the sputtering process parameters comprise cooperative parameter optimization of graded index silica and vanadium dioxide; the collaborative parameter optimization comprises sputtering parameters and O₂Partial pressure feedback control, Ar/O₂Gas proportioning, growth temperature and growth pressure.

9. The vanadium dioxide double-layer membrane element prepared by the preparation method of the vanadium dioxide double-layer membrane system according to any one of claims 3 to 8, wherein the vanadium dioxide double-layer membrane element comprises a silicon oxide double-layer membrane system based on a graded refractive index material on the basis of vanadium dioxide and an element substrate for supporting the vanadium dioxide double-layer membrane system.

10. The vanadium dioxide double-layer membrane element prepared by the preparation method of the vanadium dioxide double-layer membrane system according to claim 9 is applied to VO₂The application in the related field of intelligent phase change materials.

Technical Field

The invention belongs to the field of physics, and particularly relates to a vanadium dioxide double-layer film system, and a preparation method and application thereof.

Background

VO₂The film can instantaneously generate reversible phase change between the semiconductor and the metal under different external excitation conditions. Before and after the phase change, the crystal structure of the film is changed from a monoclinic phase to a rutile type, and the properties of the film, such as conductivity, magnetic susceptibility, light absorption, refractive index, specific heat capacity and the like, are mutated before and after the phase change. VO (vacuum vapor volume)₂Is of great interest not only because of its unique reversible MIT phase transition characteristics, but also more importantly, VO₂The phase transition temperature (68 ℃) is close to room temperature, so that the practical potential is huge. VO (vacuum vapor volume)₂The thin film element can be widely applied to the fields of aerospace, military, civil use and the like, and is concerned aboutNovel intelligent phase change material. VO in solar intelligent window, spacecraft thermal control component, optical sensor, thermistor, optical storage material, infrared remote sensing receiver, variable reflector, laser protection and uncooled focal plane detector₂The film has wide application prospect. But because of VO₂The film has low transmittance and does not meet the requirements of most application fields, so researchers in various countries try to improve the transmittance and improve the energy utilization rate by doping or plating an antireflection film and other technical means.

The graded-index thin film material means that the refractive index of the thin film gradually changes along the film thickness direction, but remains unchanged in the horizontal direction. Compared with the traditional uniform film system, the graded-index film has wider action spectrum range, reduces the degree of dependence on the incident angle of light, theoretically can realize the performances of ultra-wide wave band, full solid angle, polarization insensitivity, high transmittance and the like, and is considered as the main development form of a 'perfect' antireflection film in the future. With this inspiration, if the graded index thin film material is used for high transmission VO₂The design and preparation of the film element can greatly reduce the defect generation probability in the film growth and improve the film growth quality because the interface between film layers is eliminated by the graded-index film. Meanwhile, the graded-index film can realize the performances which are difficult to realize by a plurality of traditional layered dielectric films, such as ideal spectral characteristics, adjustable stress, ultra-smooth surface, extremely low defect density, good adhesive force and the like. In addition, the refractive index of the graded-index film is continuously adjustable, so that the film is VO with high transmittance₂The spectrum film system design of the film element increases additional degree of freedom, can effectively reduce the number of layers of the film with the designed film system structure, and reduces the preparation complexity and difficulty coefficient.

Disclosure of Invention

For solving VO₂The invention provides a vanadium dioxide double-layer film system and a preparation method and application thereof, which solve the core problem that the transmissivity of a film is low. The vanadium dioxide double-layer filmThe system utilizes materials with the function of gradual change refractive index, so that the vanadium dioxide double-layer film system realizes the performance of ultra-wide wave band, full solid angle, polarization insensitivity and high transmittance.

The invention is realized by the following technical scheme:

the double-layer film system comprises a graded-refractive-index material silicon oxide film layer and a vanadium dioxide film layer, wherein the vanadium dioxide film layer and the graded-refractive-index silicon oxide material film layer are sequentially stacked from bottom to top.

Further, the graded index material thin film layer means that the refractive index of the thin film gradually changes along the film thickness direction, but remains unchanged in the horizontal direction. Compared with the traditional uniform film system, the graded index material film has wider action spectrum band, reduces the degree of dependence on the incident angle of the light, can realize antireflection in a wide band and a full solid angle range, and is considered as the main development form of a 'perfect' antireflection film in the future.

Further, the gradient refractive index material film layer is a silicon oxide film layer.

Furthermore, the silicon oxide film layer is stable in physical and mechanical properties, has good space irradiation resistance, has high transmittance in the range of visible light and infrared bands, and the refractive index of the silicon oxide film layer can be changed within the range of 1.1-2.74 along with the change of preparation process parameters.

Furthermore, by utilizing the continuous adjustment of the refractive index of the silicon oxide thin film layer, an additional degree of freedom is added for the design of the spectral film system of the vanadium dioxide double-layer film system with high transmittance, the number of layers of thin films in the designed film system structure can be effectively reduced, and the preparation complexity and difficulty coefficient are reduced;

because the silicon oxide film layer overcomes the jump characteristic of an interface in the traditional optical film, light rays can be approximately transmitted in a curve in the silicon oxide film layer, Fresnel reflection is eliminated, compared with a uniform film system, the silicon oxide film layer has wider spectrum section of the radiation rate adjusting spectrum action, the dependence degree on the incident angle of the light rays is reduced, and the transmissivity anti-reflection in the range of a visible-infrared wide band, a polarization non-sensitive range and a full solid angle can be realized;

meanwhile, the interface between the film layers is eliminated by the silicon oxide film layer, so that the defect generation probability in the growth of a film system can be greatly reduced, and the growth quality of the film system is improved;

in addition, the silicon oxide film layer has the performances of ideal spectral characteristics, adjustable stress, super-smooth surface, extremely low defect density and good adhesive force which are difficult to realize by the traditional layered dielectric film.

The invention provides a preparation method of a vanadium dioxide double-layer film system, which adopts a sputtering process to sputter vanadium dioxide and a graded-refractive-index silicon oxide material on an element substrate in sequence to form the vanadium dioxide double-layer film system with a structure of a vanadium dioxide thin film layer/a graded-refractive-index silicon oxide thin film layer.

Further, the preparation method comprises the following specific steps:

step one, theoretically designing and optimizing the spectral performance of a vanadium dioxide double-layer film system

Adopting film system design analysis software to respectively analyze the influence trend and the change rule of the sputtering process parameters on the performance of the graded refractive index material and the performance of the vanadium dioxide film, thereby carrying out process preparation tolerance evaluation; further acquiring the refractive index distribution of the gradient refractive index material thin film layer prepared by the actual sputtering process and the process parameters of the optimized deposition growth of the vanadium dioxide thin film; on the basis, a film system is obtained, the vanadium dioxide double-layer film system is designed and optimized, and the film system has a large spectrum bandwidth range, a full solid angle space and a large radiation rate adjustment amplitude;

step two, sputtering the gradient refractive index material film layer

Analyzing the influence trend and change rule of sputtering process parameters on the performance of the graded index material in a contrast manner, performing complete optical performance characterization on the graded index material, and obtaining deposition parameters of the graded index material film layer according to the refractive index distribution requirement of silicon oxide in the step one;

step three, preparing a vanadium dioxide thin film layer

Optimizing the deposition parameters of the sputtered vanadium dioxide film and comprehensively evaluating the characteristics of the vanadium dioxide film so as to obtain the process parameters of the deposition growth of the vanadium dioxide film on the glass substrate; preparing the silicon oxide film layer of the graded-refractive-index material on the vanadium dioxide film layer according to the deposition process parameters to obtain the vanadium dioxide double-layer film system with the structure of the graded-refractive-index silicon oxide film layer/vanadium dioxide film layer;

step four, performing a first step of cleaning the substrate,

testing and evaluating the spectral performance of the element by using a spectrophotometer to complete SiO_x/VO₂The VO with simple structure, high transmissivity and stable preparation process₂And (3) preparing and characterizing a double-layer membrane system.

Further, the deposition parameters in the third step include sputtering electrical parameters, growth temperature, growth pressure, Ar/O₂Flow rate and proportion of reaction gas.

Further, in the third step, comprehensively evaluating the characteristics of the vanadium dioxide film includes:

1) characterizing the content of + 4-valent V in the film by XPS;

2) characterizing the crystal phase components by an X-ray diffractometer;

3) testing the surface shape change of the film surface by using an interferometer, and evaluating the stress characteristic;

4) VO testing by four-probe resistance measuring instrument₂Characteristic changes before and after phase change;

5) representing the phase change characteristics of the phase change temperature, the thermal hysteresis width and the phase change amplitude according to the thermal hysteresis loop;

6) measuring the spectral transmittance before and after phase change by using a spectrophotometer, and evaluating the spectral performance characteristics of the film;

7) testing and evaluating the aggregation density of the film by an ellipsometer;

8) the microstructure was characterized by field emission scanning electron microscopy.

Further, the sputtering technological parameters comprise cooperative parameter optimization of graded index silicon oxide and vanadium dioxide; the collaborative parameter optimization comprises sputtering parameters and O₂Partial pressure feedback control, Ar/O₂Gas proportioning, growth temperature and growth pressure.

Furthermore, the main means for modulating the graded index distribution of the graded index material is to adjust Speedflo software in a magnetron sputtering coating machine to dynamically control O according to the design requirement of the refractive index distribution of a graded index material film layer₂Partial pressure.

Further, the preparation method adopts a magnetron sputtering deposition technology.

The invention also provides a vanadium dioxide double-layer membrane element prepared by the preparation method of the vanadium dioxide double-layer membrane system, and the vanadium dioxide double-layer membrane element comprises the vanadium dioxide double-layer membrane system and an element substrate for bearing the vanadium dioxide double-layer membrane system.

The invention also provides a related application of the vanadium dioxide double-layer film element in the field of vanadium oxide phase-change materials.

The invention has the following beneficial technical effects:

(1) the vanadium dioxide double-layer film system utilizes the refractive index of the graded-index material film to be continuously adjustable, adds extra degree of freedom for film system spectrum design, can effectively reduce the number of layers of the film with the designed film system structure, simplifies the film system structure (only a vanadium dioxide film layer and a graded-index silicon oxide double-layer film), and reduces the preparation complexity and difficulty coefficient.

(2) The vanadium dioxide double-layer film system utilizes the silicon oxide film as a novel high-transmittance vanadium dioxide double-layer film system element which is designed and prepared, and the silicon oxide graded index material film overcomes the jump characteristic of an interface in the traditional optical film, so that light can be approximately transmitted in a curve in the silicon oxide graded index material film, Fresnel reflection is eliminated, the radiance adjusting spectrum action spectrum section of the vanadium dioxide double-layer film system is wider, the dependence degree on the light incidence angle is reduced, and the transmittance increase in a super-wide waveband and a full solid angle range can be realized.

(3) The vanadium dioxide double-layer film system utilizes the silicon oxide graded index material as the outermost layer to replace a plurality of interference interfaces in the traditional multilayer film system, thereby greatly reducing the defect generation probability in the film growth, improving the film forming quality of the film element, realizing the performances which are difficult to realize by the traditional layered dielectric film, such as ideal spectral characteristics, super-smooth surface, adjustable stress, extremely low defect density and good adhesive force, and providing favorable guarantee for developing the high-transmissivity vanadium dioxide film element with excellent performance.

Drawings

FIG. 1 is a schematic structural diagram of a vanadium dioxide double-layer film element according to an embodiment of the present invention.

Description of reference numerals: 1 is a silicon oxide film layer made of a graded-index material; 2 is a vanadium dioxide thin film layer; and 3 is an element substrate.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

On the contrary, the invention is intended to cover alternatives, modifications, equivalents and alternatives which may be included within the spirit and scope of the invention as defined by the appended claims. Furthermore, in the following detailed description of the present invention, certain specific details are set forth in order to provide a better understanding of the present invention. It will be apparent to one skilled in the art that the present invention may be practiced without these specific details.