阅读说明：本技术 一种图案化SiC微细结构及其应用 (Patterned SiC fine structure and application thereof ) 是由 王维 刘婉莎 谢春晓 杨为佑 孙振忠 于 2021-07-07 设计创作，主要内容包括：本发明涉及一种图案化SiC微细结构及其应用。该图案化SiC微细结构为在6H-SiC晶片基板上的图案化金膜上生长的SiC纳米针阵列,纳米针垂直于金膜的表面,具有渐缩的竹节状几何形状以及尖锐的尖端。纳米针长为0.1-100μm,根部直径约为180nm,尖端直径约为10nm。该图案化SiC微细结构作为太赫兹吸波材料。本发明的图案化SiC微细结构太赫兹吸波材料具有增强的吸波性能,且对入射角度不敏感。(The invention relates to a patterned SiC microstructure and application thereof. The patterned SiC microstructure is a SiC nanoneedle array grown on a patterned gold film on a 6H-SiC wafer substrate, and nanoneedles are vertical to the surface of the gold film and have a tapered bamboo-like geometric shape and a sharp tip. The nanoneedle has a length of 0.1-100 μm, a root diameter of about 180nm, and a tip diameter of about 10 nm. The patterned SiC fine structure is used as a terahertz wave-absorbing material. The patterned terahertz wave-absorbing material with the SiC fine structure has enhanced wave-absorbing performance and is insensitive to an incident angle.)

1. The patterned SiC fine structure is characterized in that the SiC fine structure is a SiC nanoneedle array vertically grown on the surface of a patterned gold film, nanoneedles in the SiC nanoneedle array have a tapered bamboo-like geometric shape and a tip, the nanoneedles are 0.1-100 mu m long, the diameter is 10-200nm, and the diameter of the tip is 10 nm.

2. A patterned SiC fine structure according to claim 1, characterized in that the SiC fine structure is a single crystal structure and the phase component is 3C — SiC.

3. A patterned SiC fine structure according to claim 1, characterized in that the patterned gold film is n n periodic geometric patterns, which are coincident with the mask openings.

4. A method of producing a patterned SiC fine structure according to any one of claims 1 to 3, characterized by comprising the steps of:

(1) depositing the 6H-SiC wafer substrate in vacuum by using a shade to obtain a patterned Au film with the thickness of 50-200nm, wherein the Au film is used as a catalyst for growing the SiC nanowire array;

(2) the SiC wafer covered with the gold film was placed on the polyureasilazane powder and placed in a vacuum oven at 10^-4Heating the furnace to 1400-1500 ℃ at a rate of 20-40 ℃/min under vacuum of Pa magnitude, and then cooling the furnace to ambient temperatureAnd finally obtaining the patterned SiC fine structure.

5. The patterned SiC microstructure of claim 4, wherein the thickness of the 6H-SiC wafer substrate is 3 to 50 μm.

6. Use of a patterned SiC microstructure according to one of claims 1 to 3 as a terahertz wave absorbing material.

Technical Field

The invention relates to a SiC terahertz wave-absorbing material and application thereof, in particular to a patterned SiC fine structure and application thereof.

Background

The terahertz technology has rapid development and application in the aspects of nondestructive detection, safety, communication and induction. The application not only needs a high-effective terahertz source and a highly sensitive filter detector, but also needs a broadband terahertz wave-absorbing material with high absorption efficiency and small size. In recent years, the metamaterial wave absorber serving as an artificial structure has the advantages of high absorption efficiency, sub-wavelength scale thickness, adjustable electromagnetic resonance response and the like, and becomes a hot point of research. At present, most metamaterial wave absorbers generally adopt a metal-medium-metal micro-structure array, although the metamaterial wave absorbers have 'perfect absorption', the absorption bandwidth is generally narrow, and the wave absorption application of the metamaterial wave absorbers is greatly limited.

In order to realize a broadband wave-absorbing metamaterial device, one method is to introduce a plurality of resonance units in a plane so as to realize a plurality of resonance peaks. However, the number of resonant cells that can be integrated in-plane is limited, and thus this approach often does not significantly extend the operating bandwidth. The other method is that a plurality of resonance units with gradually changed sizes are vertically overlapped to form a pyramid-shaped, step-shaped or conical metal-dielectric multilayer film stacking structure, so that the number of integrated resonance units is broken through, and the working bandwidth is expanded. However, the difficulty of practical preparation is significantly increased due to the required membrane structure and complex structure.

Disclosure of Invention

In view of the problems of the background art, the invention aims to provide a patterned SiC microstructure with simple preparation characteristics and broadband terahertz wave absorption performance.

The purpose of the invention can be realized by the following technical scheme: a patterned SiC microstructure is a SiC nanoneedle array vertically grown on the surface of a patterned gold film on a 6H-SiC wafer substrate. The nanoneedle in the SiC nanoneedle array has a length of 0.1-100 μm, a root diameter of about 200nm, and a tip diameter of about 10 nm.

The SiC nanoneedle with the SiC fine structure has a tapered bamboo-like geometric shape and a tip, and has obvious difference with nanobelts, nanowires and the like in appearance. In the shapes, the gradually-reduced bamboo-like or bamboo-like nanoneedle structure is more favorable for improving the terahertz wave absorbing performance.

In the above-described SiC fine structure, the patterned gold film is a geometric pattern of n n periodic arrangements, the geometric pattern coinciding with the mask hollow.

In the above-described fine SiC structure, the phase component of the nanoneedle is 3C — SiC.

In the above-described SiC fine structure, the nanoneedle has a single crystal structure.

The preparation method of the patterned SiC fine structure comprises the following steps: : (1) depositing the 6H-SiC wafer substrate in vacuum by using a shade to obtain a patterned Au film with the thickness of 50-200nm, wherein the Au film is used as a catalyst for growing the SiC nanowire array; (2) the SiC wafer covered with the gold film was placed on the polyureasilazane powder and placed in a vacuum oven at 10^-4And heating the furnace to 1400-1500 ℃ at the speed of 20-40 ℃/min under the vacuum of Pa magnitude, performing pyrolysis, and cooling to the ambient temperature along with the furnace to obtain the patterned SiC fine structure.

In the above-mentioned SiC fine structure, the polyureasilazane powder may be other organic precursors containing Si and C elements, and polyureasilazane is most preferable.

Another object of the invention is to provide an application of the patterned SiC microstructure as a terahertz wave-absorbing material.

In the application of the patterned SiC microstructure, the patterned SiC microstructure on the multi-resonance unit terahertz wave absorbing unit formed by the patterned gold film and the 6H-SiC wafer substrate can effectively widen the working bandwidth of terahertz wave absorption, and is insensitive to the incident angle.

Compared with the prior art, the invention has the following advantages:

1. the invention realizes the preparation of the terahertz wave absorbing material with the patterned SiC fine structure.

2. The patterned SiC micro-structure terahertz wave absorbing material prepared by the invention can effectively widen the working bandwidth of the simple multi-resonance-unit terahertz wave absorbing unit, and the preparation method is simple and convenient.

3. The patterned SiC microstructure terahertz wave absorbing material prepared by the invention is insensitive to the incident angle of terahertz waves.

Drawings

FIG. 1 is a top view of a Scanning Electron Microscope (SEM) with low magnification of a terahertz wave absorbing material with a patterned SiC microstructure according to the invention;

FIG. 2 is a schematic perspective view of a unit structure of the patterned SiC fine structure terahertz wave absorbing material of the invention;

FIG. 3 is a high power electron microscope image of a nanoneedle of the patterned SiC microstructure terahertz wave absorbing material of the present invention; wherein (A) is a typical TEM image of a single SiC nano needle, (B) is a TEM image of an area A in (A) and shows that the SiC nano needle is a tapered bamboo-like structure, (C) is a typical TEM image of the tip of the SiC nano needle, and (D) is a typical SEM image of the SiC nano needle array;

FIG. 4 is a terahertz wave absorption spectrum of a different structure under normal incidence according to the present invention; the solid line represents an actually measured terahertz absorption spectrogram of the whole structure, and the dotted line represents a simulated terahertz absorption spectrogram of the structure without the SiC nanoneedle;

FIG. 5 is an actually measured absorption spectrum of terahertz waves caused by changes of incident angles of terahertz sources obliquely incident on TE polarization according to the invention;

FIG. 6 is an actually measured absorption spectrum of the terahertz wave caused by the change of the incident angle of the terahertz source obliquely incident to the TM polarization according to the invention;

in the figure: 1. SiC nanoneedle array, 2, patterned gold film, 3, 6H-SiC wafer substrate.

Detailed Description

The following are specific embodiments of the present invention and are further described with reference to the accompanying drawings, but the present invention is not limited to these embodiments.

In the case of the example 1, the following examples are given,

the embodiment provides a patterned SiC fine structure, the SiC fine structure is a SiC nano needle array 1 vertically grown on the surface of a patterned gold film 2, nano needles in the SiC nano needle array have a tapered bamboo-like geometric shape and tips, the nano needles have the length of 0.1-100 mu m and the diameter of 10-200nm, the diameter of the tips is 10nm, the SiC fine structure is a single crystal structure, phase components are 3C-SiC, catalyst particles are not arranged at the top end, and (gold) catalyst particles are not arranged at the top end, so that terahertz wave absorption is facilitated; the patterned gold film 2 is n n geometric patterns arranged periodically, and the geometric patterns are consistent with the hollow parts of the mask.

Referring to fig. 2, a schematic three-dimensional view of a unit structure of the prepared terahertz wave absorbing material with the patterned SiC microstructure is shown.

The present embodiment provides a method for producing a patterned SiC fine structure, including the steps of:

(1) depositing the 6H-SiC wafer substrate 3 in vacuum by using a mask to obtain a patterned Au film with the thickness of 50-200nm, wherein the Au film is used as a catalyst for growing the SiC nanowire array;

(2) the SiC wafer covered with the gold film was placed on the polyureasilazane powder and placed in a vacuum oven at 10^-4And heating the furnace to 1400-1500 ℃ at the speed of 20-40 ℃/min under the vacuum of Pa magnitude, and then cooling to the ambient temperature along with the furnace to obtain the patterned SiC fine structure.

The thickness of the 6H-SiC wafer substrate 3 is 3-50 μm.

The embodiment provides application of a patterned SiC microstructure as a terahertz wave-absorbing material. The patterned SiC fine structure terahertz wave absorbing material can effectively widen the working bandwidth of the simple multi-resonance unit terahertz wave absorbing unit, and is insensitive to the incident angle of terahertz waves.

In the case of the example 2, the following examples are given,

this example provides a method of preparing a patterned SiC fine structure,

(1) depositing a 5-micron 6H-SiC wafer substrate in vacuum by using a mask to obtain a 50 nm-thick patterned Au film, wherein the gold film pattern is a circle which is symmetrically, uniformly and orthogonally distributed on the 6H-SiC wafer substrate with the period of 60 microns along a 45-degree axis, and the diameters of the circles are 28 microns and 20 microns respectively;

(2) in a high purity alumina crucible, a SiC wafer coated with a gold film is placed on a polyureasilazane powder and covered with graphite paper, the crucible is placed in a vacuum oven at 10^-4And heating the furnace to 1500 ℃ at the speed of 30 ℃/min under vacuum of Pa magnitude for pyrolysis, and then cooling the furnace to the ambient temperature to obtain the patterned SiC fine structure terahertz wave absorbing material.

The terahertz wave absorbing material with the patterned SiC fine structure prepared in the embodiment 2 is placed on a metal substrate for wave absorption performance test, and the test result is shown in the figure.

Fig. 1 is a top view of a low-power Scanning Electron Microscope (SEM) of the terahertz wave absorbing material with the patterned SiC microstructure prepared in example 1. The SiC nanometer needles are shown to be fully distributed on the surface of the patterned Au film and have higher arrangement density.

Fig. 3 is a Transmission Electron Microscope (TEM) image of the nanoneedle of the patterned terahertz wave absorbing material with SiC microstructure prepared in example 1. The prepared SiC nanoneedle structure is 10-60 mu m long, presents a tapered novel geometric shape similar to bamboo and a sharp and clean tip, the root diameter of the nanoneedle is about 180nm, and the tip diameter of the needle is about 10 nm.

The terahertz wave absorbing material with the patterned SiC fine structure prepared in the embodiment 2 is used for measuring a wave absorbing pattern on a terahertz time-domain spectrometer and is compared with a simulation wave absorbing pattern of a structure with a SiC nanoneedle removed, so that the terahertz wave absorbing material with the patterned SiC fine structure has excellent terahertz broadband wave absorbing performance. Referring to fig. 4, terahertz wave absorption spectra of different structures under normal incidence; the solid line represents an actually measured terahertz absorption spectrogram of the whole structure, and the dotted line represents a simulated terahertz absorption spectrogram of the structure without the SiC nanoneedle;

the terahertz wave absorbing material with the patterned SiC fine structure prepared in the embodiment 2 is used for measuring wave absorbing patterns with different polarizations and incident angles on a terahertz time-domain spectrometer, and the terahertz wave absorbing material is insensitive to the polarizations and the incident angles. Referring to fig. 5-6, the influence of the incident angle change of the terahertz source of the TE polarization oblique incidence and the TM polarization oblique incidence on the actually measured absorption spectrogram of the terahertz wave is shown.

In the preparation embodiment and the alternative scheme of the patterned SiC microstructure terahertz wave absorbing material, the pattern of the Au film can also be a top metal layer of other multi-resonance metal-medium-metal microstructure arrays, such as other wafers with different sizes, other square sheets with different sizes, other cross sheets with different sizes, and the like.

In the preparation embodiment and the alternative scheme of the patterned SiC microstructure terahertz wave absorbing material, the thickness of the 6H-SiC wafer substrate can be other sizes within the range of 3-50 microns except 40 microns, and the material can be obtained by performing simulation optimization design on resonance wave absorption performance through the pattern of the Au film.

In the preparation embodiment and the alternative scheme of the patterned SiC microstructure terahertz wave absorbing material, the pyrolysis temperature can be 1400 ℃, 1410 ℃, 1420 ℃, 1430 ℃, 1440 ℃, 1460 ℃, 1470 ℃, 1480 ℃, 1490 ℃ and 1500 ℃.

In the preparation embodiment and the alternative scheme of the patterned terahertz wave absorbing material with the SiC fine structure,

the temperature rise rate of pyrolysis can also be 20 ℃/min, 22 ℃/min, 23 ℃/min, 24 ℃/min, 25 ℃/min, 26 ℃/min, 27 ℃/min, 28 ℃/min, 29 ℃/min, 31 ℃/min, 32 ℃/min, 33 ℃/min, 34 ℃/min, 35 ℃/min, 36 ℃/min, 37 ℃/min, 38 ℃/min, 39 ℃/min, 40 ℃/min.

The terahertz broadband wave absorbing material is compounded with a multi-resonance terahertz narrowband wave absorbing metamaterial composed of different patterned gold films and a 6H-SiC wafer substrate, and the terahertz broadband wave absorbing performance can be obtained by optimally regulating and controlling the fine structures such as the average length of the SiC nanoneedle array.

In view of numerous embodiments of the preparation scheme of the patterned terahertz wave absorbing material with the SiC fine structure, numerous experimental data of each embodiment are huge, and the embodiment is not suitable for being enumerated and explained one by one here, but the contents to be verified of each embodiment are close to the final conclusion, so that the verification contents of each embodiment are not explained one by one here, and only the embodiment 1 is taken as a representative to explain the excellence of the application of the invention.

The embodiments herein are not exhaustive of the technical scope of the present invention, and are within the scope of the present invention.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the invention as defined in the appended claims.

While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.