阅读说明：本技术 一种二氧化硅—二氧化钒多级阵列结构及其制备方法 (Silicon dioxide-vanadium dioxide multistage array structure and preparation method thereof ) 是由 梁继然 张珂 樊雅婕 于立泽 于 2020-02-29 设计创作，主要内容包括：本发明公开了一种二氧化硅—二氧化钒多级阵列结构及其制备方法,以自组装微米尺寸二氧化硅球为模板,用磁控溅射加快速退火的方式制备二氧化钒薄膜,形成球面上及球缝隙中的二氧化钒阵列结构。本发明制备应用于太赫兹吸收器的二氧化硅—二氧化钒多级阵列结构,使顶层阵列和中间介质层的制备过程相结合,方法较为简单,控制的工艺条件较少,比光刻法成本低廉。(The invention discloses a silicon dioxide-vanadium dioxide multistage array structure and a preparation method thereof. The method for preparing the silicon dioxide-vanadium dioxide multistage array structure applied to the terahertz absorber combines the preparation processes of the top layer array and the middle medium layer, is simpler, has fewer controlled process conditions, and has lower cost than a photoetching method.)

1. A preparation method of a silicon dioxide-vanadium dioxide multistage array structure is characterized by comprising the following steps:

(1) cleaning of the sapphire substrate:

sequentially putting the sapphire substrate into deionized water, absolute ethyl alcohol and acetone, and respectively carrying out ultrasonic cleaning; cleaning with deionized water, and drying in a constant temperature drying oven for later use;

(2) preparation of periodic SiO2 spheres:

placing the cleaned substrate in the step (1) at the bottom of a weighing bottle, slowly injecting deionized water into the weighing bottle to more than half of the volume, preparing monodisperse silicon dioxide spheres and n-butyl alcohol into suspension, dropwise adding the suspension onto the liquid level of the weighing bottle by a dropper, placing the weighing bottle on a heating table, heating and evaporating, quickly agglomerating the silicon dioxide spheres on the liquid level to form a film, and evaporating the n-butyl alcohol and the deionized water to dryness to form the substrate covered with the silicon dioxide sphere periodic array;

(3) preparing a vanadium film:

placing the substrate with the surface covered with the silicon dioxide balls obtained in the step (2) in a vacuum chamber of DPS-III type ultrahigh vacuum target magnetron sputtering equipment, setting sputtering working pressure in an argon environment by taking high-purity metal vanadium as a target material, adjusting sputtering power, and beginning to deposit a vanadium film after parameters are set;

(4) preparation of vanadium dioxide film

And (4) placing the vanadium film prepared in the step (3) into a rapid annealing furnace for rapid oxidation thermal annealing.

2. The method for preparing the silica-vanadium dioxide multilevel array structure according to claim 1, wherein the sputtering time in the step (3) is 10-15 min.

3. The method for preparing the silicon dioxide-vanadium dioxide multistage array structure according to claim 1, wherein the gas introduced into the rapid annealing furnace in the step (4) is high-purity oxygen, the annealing process is divided into three stages of temperature rise, temperature preservation and temperature reduction, and the temperature preservation temperature is set; the temperature-keeping time parameter is adjustable and ranges from 50s to 60 s.

4. The silica-vanadium dioxide multilevel array structure prepared by the method of claim 1.

Technical Field

The invention relates to a preparation method of a silicon dioxide-vanadium dioxide multistage array structure, in particular to a preparation method of a silicon dioxide-vanadium dioxide multistage array structure for a terahertz absorber.

Background

In the electromagnetic spectrum, the region between the infrared wave and the millimeter wave, i.e., the frequency range of 0.1 to 10Thz, corresponds to the terahertz wave band. In recent years, with the research of metamaterials and the development of micro-nano processing technology, terahertz metamaterial absorbers are gradually paid attention to by researchers. The terahertz functional device can be widely applied to quality detection in industry, stealth anti-reconnaissance technology in military, safety inspection in social life, environmental monitoring and the like.

Generally, the terahertz metamaterial absorber has three layers of structures, namely a top layer array pattern, a bottom metal total reflection layer and a middle dielectric layer. Wherein, the bottom metal total reflection layer plays a role of completely blocking transmission; the middle dielectric layer is used as a resonant cavity, and energy loss is used up after the terahertz waves are reflected for multiple times in the middle dielectric layer; according to the theory of destructive interference, because electromagnetic waves are reflected and transmitted on the surface of the air-top layer structure, the transmission part can be reflected for many times and attenuated continuously in the absorber structure, and finally the absorption is successful. In order to realize the dynamic absorption of terahertz waves, researchers try to actively respond to terahertz waves by using functional materials such as doped semiconductors, liquid crystals and graphene; in order to achieve broadband absorption, researchers have attempted to superimpose periodic structures on a two-dimensional plane, or to stack multiple layers of structures in three-dimensional space. However, in order to obtain good broadband, dynamic modulation performance, the absorber is studied at the expense of structural complexity, which inevitably increases the cost of the manufacturing process. As we know, the semiconductor-metal phase change material can be used as the top layer and the middle layer of the absorber structure, the semiconductor and the bottom metal layer form the metamaterial together, when external excitation is not available, the semiconductor does not generate terahertz radiation response, and after the excitation is added, the semiconductor material is gradually metalized and generates resonance response, so that the equivalent structure of the metamaterial is changed. Therefore, the active phase-change material enables the dynamic regulation of terahertz absorption to be possible.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a preparation method of a silicon dioxide-vanadium dioxide multistage array structure, which solves the problems of complex structure and high process cost of a terahertz absorber in the prior art.

The technical scheme of the invention is as follows:

a preparation method of a silicon dioxide-vanadium dioxide multilevel array structure comprises the following steps:

(1) cleaning of the sapphire substrate:

sequentially putting the sapphire substrate into deionized water, absolute ethyl alcohol and acetone, and respectively carrying out ultrasonic cleaning; cleaning with deionized water, and drying in a constant temperature drying oven for later use;

(2) preparation of periodic SiO2 spheres:

placing the cleaned substrate in the step (1) at the bottom of a weighing bottle, slowly injecting deionized water into the weighing bottle to more than half of the volume, preparing monodisperse silicon dioxide spheres and n-butyl alcohol into suspension, dropwise adding the suspension onto the liquid level of the weighing bottle by a dropper, placing the weighing bottle on a heating table, heating and evaporating, quickly agglomerating the silicon dioxide spheres on the liquid level to form a film, and evaporating the n-butyl alcohol and the deionized water to dryness to form the substrate covered with the silicon dioxide sphere periodic array;

(3) preparing a vanadium film:

placing the substrate with the surface covered with the silicon dioxide balls obtained in the step (2) in a vacuum chamber of DPS-III type ultrahigh vacuum target magnetron sputtering equipment, setting sputtering working pressure in an argon environment by taking high-purity metal vanadium as a target material, adjusting sputtering power, and beginning to deposit a vanadium film after parameters are set;

(4) preparation of vanadium dioxide film

And (4) placing the vanadium film prepared in the step (3) into a rapid annealing furnace for rapid oxidation thermal annealing.

And (4) sputtering for 10-15min in the step (3).

The gas introduced into the rapid annealing furnace in the step (4) is high-purity oxygen, the annealing process is divided into three stages of temperature rise, heat preservation and temperature reduction, and the heat preservation temperature is set; the temperature-keeping time parameter is adjustable and ranges from 50s to 60 s.

The silicon dioxide-vanadium dioxide multistage array structure prepared by the method.

The invention has the beneficial effects that:

1) the silicon dioxide-vanadium dioxide multilevel array structure applied to the terahertz absorber is prepared, so that the preparation processes of the top layer array and the middle medium layer are combined, the method is simpler, the controlled process conditions are fewer, and the cost is lower than that of a photoetching method.

2) The preparation of the multilevel array is based on a two-dimensional self-assembly method, and the method is widely used for preparing photonic crystals at present, and has mature process and good repeatability.

The vanadium dioxide film is prepared by adopting the vanadium dioxide active phase change material, taking the micron-sized silicon dioxide balls as templates and adopting a magnetron sputtering and rapid annealing mode by means of the micron-sized silicon dioxide balls, so that the vanadium dioxide array structure on the spherical surface and in the gaps of the spherical surface is formed.

Drawings

FIG. 1 is a preparation flow chart of a silicon dioxide-vanadium dioxide multistage structure micro-nano array; (a) a volleyball process, (b) vanadium thin film growth, (c) annealing to form vanadium dioxide, (d) a multilevel array schematic diagram;

FIG. 2 is a schematic diagram of a silica spherical array self-assembly;

FIG. 3 is a graph comparing the electrical properties of three sets of samples for different annealing soak times; (a) annealing and heat preservation for 50s after sputtering for 15 min; (b) a result of 55s of annealing heat preservation after sputtering for 15min (c) a result of 60s of annealing heat preservation after sputtering for 15 min;

FIG. 4 is a topography of a multi-stage micro-nano structure array under an optical microscope; (a) a topography of the spherical array magnified 1000 times (b) a topography of the spherical gap array magnified 1000 times.

Detailed Description

The present invention is further illustrated below with reference to specific examples, which are intended to be illustrative only and not to limit the scope of the invention.