CN118419916B - Quasi-carbon nanotube structure and manufacturing method thereof - Google Patents

Abstract

A quasi-carbon nanotube structure and a method for making the same, the quasi-carbon nanotube structure comprising a carbon nanotube or a carbon nanostrip, the carbon nanotube having an axial linear defect formed by atomic-level trimming, the carbon nanostrip curling to form a stable quasi-carbon nanotube structure containing an axial linear defect; wherein the linear defect realizes chirality transformation and band gap width regulation, so that the semiconductor chiral carbon nanostructure is transformed into a metallic carbon nanostructure. An atomic-level manufacturing method is provided to achieve the enhancement of the conductivity and chirality transformation of carbon nanotubes. The advantage of this method is that the chirality of the initial carbon nanotube structure is not required, and the chirality transformation from the semiconductor carbon nanotube to the metallic carbon nanostructure is achieved by introducing the required axial linear defect; the metallic characteristics of the metallic carbon nanotube structure are enhanced and regulated. The degenerate state of the introduced linear defect significantly improves the conductivity of the carbon nanotube, realizes chirality regulation and simplifies the regulation method.

Description

Quasi-carbon nanotube structure and method for making the same

Technical Field

The present invention relates to the technical field of carbon nano material structure modification and chirality regulation, and in particular to a quasi-carbon nanotube structure and a manufacturing method and chirality regulation thereof.

Background Art

Carbon nanotubes have a wide range of applications in nanoelectronic devices, optoelectronic integration, nanostructure antennas, nano-optical antennas, energy storage materials, contact coupling and other fields due to their high surface area, high aspect ratio and special nanoscale structure. Carbon nanotubes can be divided into metallic and semiconducting carbon nanotubes according to their structure and chirality (i.e. the arrangement of carbon atoms on the tube wall). Metallic carbon nanotubes exhibit conductivity, while semiconducting carbon nanotubes exhibit semiconductor properties. However, due to the complexity of the growth process of carbon nanotubes and the difficulty in precise control, achieving efficient and controllable growth of carbon nanotubes with specific chirality is still a major technical problem, and there are still great challenges in controlling the conductivity and chirality of carbon nanotubes. At present, the conductivity control technology of carbon nanotubes is mainly achieved through purification and separation methods and chemical doping methods. Purification and separation methods include molecular recognition technology, density gradient centrifugation, cross electric field method and selective chemical reaction method. The chemical doping method is to introduce dopants (such as nitrogen, boron, metal atoms, surface functional groups, etc.) into carbon nanotubes to change their electronic structure and thus regulate their conductivity. The purification and doping methods of chirality generally have the problems of cumbersome steps and poor controllability. Therefore, it is urgent to obtain a simple, efficient and easy-to-control scheme to regulate the electronic properties of carbon nanotubes.

It should be noted that the information disclosed in the above background technology section is only used for understanding the background of the present application, and therefore may include information that does not constitute prior art known to ordinary technicians in the field.

Summary of the invention

The main purpose of the present invention is to overcome the defects of the above-mentioned background technology and provide a quasi-carbon nanotube structure and a method for making the same.

To achieve the above object, the present invention adopts the following technical solutions:

A quasi-carbon nanotube structure includes a carbon nanotube or a carbon nanostrip, wherein the carbon nanotube is cut to form an axial linear defect, and the carbon nanostrip is curled to form a stable quasi-carbon nanotube structure containing an axial linear defect; wherein the linear defect realizes the regulation of chirality and band gap width, so that the semiconductor chiral carbon nanostructure is transformed into a metallic carbon nanostructure. Furthermore, by introducing the degenerate state of the linear defect, the conductive properties of the curled metallic carbon nanostrip structure are significantly improved.

Further:

The diameter of the carbon nanotube is 0.8 to 30 nanometers.

The initial width of the carbon nanoribbon is 1 to 100 nanometers.

A method for manufacturing a quasi-carbon nanotube structure comprises: cutting and forming axial linear defects on a carbon nanotube by an atomic scale manufacturing method such as plasma etching, ion beam etching or laser cutting.

Furthermore, the laser cutting method comprises:

dispersing carbon nanotubes in a solvent;

Drop coating or spray coating of the dispersed carbon nanotube solution on a clean substrate, and drying the solution to form a uniformly distributed carbon nanotube film;

The carbon nanotubes are trimmed using a femtosecond laser or attosecond laser rapid cold cutting method to form axial linear defects.

A method for manufacturing a quasi-carbon nanotube structure comprises: annealing a carbon nanotube strip in an electric field to curl the carbon nanotube strip to form a stable quasi-carbon nanotube structure containing axial linear defects.

Further, the carbon nanoribbons are annealed in an electric field to curl the carbon nanoribbons to form a stable quasi-carbon nanotube structure containing axial linear defects, which specifically includes:

Prepare graphene strip substrate using photolithography technique;

Graphene strips are prepared on a substrate by chemical vapor deposition;

Using organic solvents to remove photoresist;

Annealing in an electric field causes the graphene strips to curl up to form a stable quasi-carbon nanotube structure containing axial linear defects;

The prepared quasi-carbon nanotube structure is peeled off from the substrate by electrolysis.

Furthermore, the substrate is a Cu substrate.

Furthermore, the annealing in the electric field includes: under vacuum conditions, applying a strong electric field of 2.5-5 kV/m perpendicular to the substrate direction, heating the graphene strip containing the substrate to 1200 K-1300 K, and then annealing for 1 to 10 hours to allow the curled nanoribbon to achieve structural stability, and then slowly cooling to room temperature with the annealing equipment.

The present invention has the following beneficial effects:

The present invention proposes an innovative quasi-carbon nanotube structure and a method for making it, which breaks through the limitations of traditional technologies and provides a simple, efficient and easy-to-control solution to regulate and enhance the electrical conductivity of carbon nanotubes. The present invention can introduce axial linear defects through atomic-level operations or atomic-level manufacturing technology without requiring the chirality of the initial carbon nanotubes, thereby achieving the transformation of carbon nanotubes from semiconductor to metallic properties, effectively regulating their band gap width, and enhancing their electrical conductivity. This transformation is not only applicable to armchair, zigzag, and other carbon nanotubes in arbitrary chiral states, but also significantly improves the electrical conductivity of carbon nanotubes through the degenerate state of the introduced linear defects. The present invention provides a quasi-carbon nanotube structure and a curled nanostrip structure with high electrical conductivity, which are applied to carbon nanostructure antennas and arrays in microwave, millimeter wave, terahertz and other wavebands, effectively solving the problems of low electrical conductivity and high impedance matching.

The significant advantage of the present invention is also the flexibility and compatibility of its implementation method, which can be combined with a variety of existing manufacturing processes without making major changes to the production process, thus helping to achieve large-scale application and production. In addition, the quasi-carbon nanotube structure changes little after the introduction of linear defects, which helps to maintain its excellent electrical conductivity for a long time and reduce performance degradation during use. Importantly, the present invention simplifies the regulation process and does not need to consider the chirality of carbon nanotubes, which is of great significance for improving production efficiency and reducing costs. Overall, the present invention not only improves the conductivity and field emission performance of carbon nanotubes, but also provides a new mechanism and means for regulating the electronic properties of carbon nanotubes.

Compared with the existing technology, the present invention has the following advantages and outstanding effects:

1) Compared with the existing technology, the present invention is flexible in its implementation method, compatible with a variety of manufacturing processes, does not require major changes to the production process, and is conducive to large-scale application and production.

2) Once linear defects are introduced, the structure of carbon nanotubes changes little, their conductive properties can be maintained for a long time, and they are not easily degraded during use.

3) There is no need to consider the chirality of carbon nanotubes, which simplifies the regulation process.

Other beneficial effects of the embodiments of the present invention will be further described below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of three structures of complete carbon nanotubes (a), linear defect carbon nanotubes (b) and curved carbon nanoribbons (c) according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of the energy band structure of a complete carbon nanotube (a) and the energy band structure of a linear defect quasi-carbon nanotube structure according to an embodiment of the present invention (b).

DETAILED DESCRIPTION

The following is a detailed description of the embodiments of the present invention. It should be emphasized that the following description is only exemplary and is not intended to limit the scope and application of the present invention.

It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, connection can be used for fixing as well as for coupling or communication.

It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

Referring to FIG. 1 , an embodiment of the present invention provides a quasi-carbon nanotube structure (see FIG. 1 (b)), comprising a carbon nanotube, wherein the carbon nanotube is cut to have an axial linear defect, wherein the linear defect realizes the regulation of chirality and band gap width, so that the semiconductor chiral carbon nanostructure is transformed into a metallic carbon nanostructure.

In some embodiments, the method for manufacturing the quasi-carbon nanotube structure includes: cutting the carbon nanotube to form axial linear defects by plasma etching, ion beam etching or laser cutting.

Referring to FIG. 1 , an embodiment of the present invention provides another quasi-carbon nanotube structure (see FIG. 1 (c)), comprising a carbon nanotube strip, wherein the carbon nanotube is cut to form an axial linear defect, and the carbon nanotube strip is curled to form a quasi-carbon nanotube structure containing an axial linear defect; wherein the linear defect realizes the regulation of chirality and band gap width, so that the semiconductor chiral carbon nanostructure is transformed into a metallic carbon nanostructure. Furthermore, by introducing the degenerate state of the linear defect, the conductive properties of the curled metallic carbon nanostrip structure are significantly improved.

In some embodiments, the method for manufacturing the quasi-carbon nanotube structure includes: annealing the carbon nanoribbons in an electric field to curl the carbon nanoribbons to form a stable quasi-carbon nanotube structure containing axial linear defects.

The specific embodiments of the present invention are further described below.

The structures of the two quasi-carbon nanotube structures of the embodiments of the present invention are shown in (b) and (c) of FIG. 1 , and contain linear defects. The quasi-carbon nanotube structure is a high-purity conductive material. As shown in (b) of FIG. 2 , the energy band gap of the carbon tube is occupied by a large number of electronic states, and the carbon nanotube is transformed from a semiconductor to a metal conductor. The degenerate state of the linear defect introduced into the quasi-carbon nanotube structure can greatly improve the conductivity of the carbon nanotube. The present invention is applicable to, but not limited to, the regulation of the conductivity of armchair, zigzag and other various chiral carbon nanotubes.

The quasi-carbon nanotube structure introduces linear defects to form carbon nanotubes with axial openings. Due to the degeneration of the hanging electrons, the electron energy level near the Fermi surface in the material band structure is increased, resulting in good conductivity regardless of the chirality of the carbon nanotubes. Therefore, the present invention does not need to consider chirality, and the axial linear defects can not only transform the semiconductor carbon tubes into metallic carbon tubes, but also enhance the conductivity of the metallic carbon tubes.

In some embodiments, a method for making a quasi-carbon nanotube structure improves the conductivity of carbon nanotube materials and structures, the method comprising the following steps:

1) Preparation of carbon nanotubes: Select carbon nanotubes with a diameter of 0.8 to 30 nanometers as the starting material.

2) Etching of linear defects:

Linear defects are introduced into carbon nanotubes, which can be achieved by plasma etching, ion beam etching or laser cutting. During the etching process, the density and distribution of defects can be adjusted by precisely controlling etching parameters (such as time, temperature, gas concentration, etc.).

Thus, the quasi-carbon nanotube structure with axial linear defects is formed into carbon tubes with new electronic properties and good electrical conductivity.

In some embodiments, another method for making a quasi-carbon nanotube structure improves the conductivity of carbon nanotube materials and structures, the method comprising the following steps:

1) Preparation of carbon nanoribbons: Select carbon nanoribbons with a width of 1 to 100 nanometers as the starting material.

2) The carbon nanoribbons are annealed in an electric field to cause them to curl and form a stable quasi-carbon nanotube structure with axial linear defects.

Thus, the carbon nanoribbon with curvature is rolled into a quasi-carbon nanotube structure with axial linear defects, forming a carbon tube with new electronic properties and good electrical conductivity.

The quasi-carbon nanotube structure of the present invention introduces linear defects of carbon nanotubes by cutting carbon nanotubes, or forms a quasi-carbon nanotube structure with linear defects by curling carbon nano ribbons, so as to achieve the regulation of chirality and band gap width. The present invention does not need to consider the chirality of the initial quasi-carbon nanotube structure, and can transform the semiconductor chiral carbon nanotube into a metallic carbon nanostructure through atomic-level operation or atomic-level manufacturing technology, so as to achieve the regulation of chirality and band gap width. The degenerate state of the introduced linear defects can greatly improve the conductivity of carbon nanomaterials and structures. The present invention can improve the conductivity and field emission performance of carbon nanotubes.

Production Example 1

Laser cutting to fabricate quasi-carbon nanotube structures containing linear defects

1) Dispersing nanotubes: Disperse carbon nanotubes in a solvent (ethanol, isopropanol, water, etc.) to avoid agglomeration.

2) Prepare the substrate: drip or spray the dispersed carbon nanotube solution onto a clean substrate (such as a silicon wafer, a glass wafer, etc.) and allow it to dry to form a uniformly distributed carbon nanotube film.

3) Laser cutting process: Select a femtosecond laser and use a microscope or other imaging device to accurately locate the carbon nanotube area that needs to be cut. Control the movement path of the laser beam on the sample surface so that it scans and cuts the carbon nanotubes along a predetermined trajectory. Since the laser beam locally heats the carbon nanotubes, the material vaporizes or breaks, thereby achieving cutting. Avoid excessive damage to adjacent areas during the cutting process.

4) Characterize the cutting effect: After cutting, clean the sample to remove the debris and impurities generated during the cutting process. Use a microscope (such as scanning electron microscope SEM, transmission electron microscope TEM) to characterize the cutting effect. At this time, the carbon nanotubes are distributed with linear defects of different sizes. The linear defects introduce a large number of pendant electrons, which makes the carbon nanotubes conduct from semiconductors to metal conductors.

Production Example 2

Fabrication of quasi-carbon nanotube structures with linear defects by curvature carbon nanoribbon method

2) Prepare the Cu substrate using photolithography technology to define the width and length of the graphene strips. Through photoresist coating, pattern exposure, and development steps, a graphene strip substrate with a width of 5 nanometers to 40 nanometers is prepared.

3) Graphene strips were prepared on a copper substrate using chemical vapor deposition.

4) Use organic solvent to remove the photoresist.

5) Under vacuum conditions, a strong electric field of 2.5-5 kV/m is applied perpendicular to the substrate, and the graphene strip containing the substrate is heated to 1200 K-1300 K. Due to the effect of the electric field and heating, the graphene carbon nanoribbon will curl up to form a quasi-carbon nanotube structure containing linear defects, and then anneal for several hours and slowly cool down to obtain a stable quasi-carbon nanotube structure.

6) Exfoliation of carbon nanotubes by electrolysis.

In summary, the present invention proposes an innovative quasi-carbon nanotube structure and a method for making the same, which breaks through the limitations of traditional technologies and provides a simple, efficient and easy-to-control solution to regulate the electrical conductivity of carbon nanotubes. The present invention can introduce axial linear defects through atomic-level operations or atomic-level manufacturing technology, without considering the chirality of the initial carbon nanotubes, to achieve the transition of carbon nanotubes from semiconductor to metallic properties, and effectively regulate their band gap width. This transition is not only applicable to armchair, zigzag and other carbon nanotubes of arbitrary chiral states, but also significantly improves the electrical conductivity of carbon nanotubes through the degenerate state of the introduced linear defects.

In general, the present invention not only improves the electrical conductivity and field emission performance of carbon nanotubes, but also provides a new mechanism and means for regulating the electronic properties of carbon nanotubes.

Compared with the existing technology, the present invention also has the following advantages and outstanding effects:

1) Compared with the existing technology, the present invention is flexible in its implementation method, compatible with a variety of manufacturing processes, does not require major changes to the production process, and is conducive to large-scale application and production.

2) Once linear defects are introduced, the structure of carbon nanotubes changes little, their conductive properties can be maintained for a long time, and they are not easily degraded during use.

3) There is no need to consider the chirality of carbon nanotubes, which simplifies the regulation process.

The above content is a further detailed description of the present invention in combination with specific/preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, it can also make several substitutions or modifications to these described embodiments, and these substitutions or modifications should be regarded as belonging to the protection scope of the present invention. In the description of this specification, the description of reference terms "an embodiment", "some embodiments", "preferred embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily target the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In the absence of mutual contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions and modifications can be made herein without departing from the scope of protection of the patent application.

Claims (2)

1. The manufacturing method of the quasi-carbon nanotube structure is characterized by comprising the following steps: crimping the carbon nanoribbon by annealing the carbon nanoribbon in an electric field to form a stable quasi-carbon nanotube structure comprising axial linear defects;

the method specifically comprises the following steps:

preparing a graphene strip substrate by using a photolithography technique;

preparing graphene strips on a substrate by a chemical vapor deposition method;

Removing the photoresist by using an organic solvent;

Annealing in an electric field to curl the graphene ribbon to form a stable quasi-carbon nanotube structure containing axial linear defects; the annealing in the electric field comprises: under the high vacuum condition, applying a strong electric field of 2.5-5 kV/m perpendicular to the direction of the substrate, heating the graphene strip containing the substrate to 1200-K-1300K, then carrying out annealing treatment for 1-10 hours to ensure that the curled nano strip reaches stable structure, and then slowly cooling to room temperature along with annealing equipment;

and stripping the prepared quasi-carbon nano tube structure from the substrate by adopting an electrolysis mode.

2. The method of claim 1, wherein the substrate is a Cu substrate.