Quasi-carbon nanotube structure and manufacturing method therefor

Abstract

A quasi-carbon nanotube structure and a manufacturing method therefor. The quasi-carbon nanotube structure comprises a carbon nanotube or a carbon nanoribbon. Axial linear defects are formed on the carbon nanotube by means of atomic-level tailoring, and the carbon nanoribbon is curled to form a stable quasi-carbon nanotube structure containing axial linear defects, wherein the linear defects realize chiral inversion and bandgap width control, such that a semiconducting chirality carbon nanostructure is inverted into a metallic carbon nanostructure. Provided is an atomic-level manufacturing method for implementing electrical conductivity enhancement and chiral inversion of a carbon nanotube. The advantages of the method lie in that without requiring the chirality of an initial carbon nanotube structure, and by means of introducing required axial linear defects, the chiral inversion from a semiconducting carbon nanotube to a metallic carbon nanostructure is achieved, and the enhancement and control of metallic properties of the metallic carbon nanotube structure are also achieved. The introduced linear defects lead to degeneracy lifting, thus significantly improving the electrical conductivity of a carbon nanotube, achieving chirality control, and simplifying the chirality control mode.

Description

Quasi-carbon nanotube structure and manufacturing method thereof TECHNICAL FIELD

[0001] The present application relates to the technical field of carbon nanomaterial structure modification and chirality control, and particularly relates to a quasi-carbon nanotube structure, a manufacturing method thereof and chirality control. BACKGROUND

[0002] Carbon nanotubes have a wide range of applications in the fields of nanoelectronic devices, optoelectronic integration, nanostructure antennas, nano-optical antennas, energy storage materials, contact coupling, etc. due to their high surface area, high aspect ratio and special nano-scale 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 electrical conductivity, while semiconducting carbon nanotubes exhibit semiconductor properties. However, due to the complexity and difficulty of precisely controlling the growth process of carbon nanotubes, it is still a major technical challenge to achieve efficient and controllable growth of carbon nanotubes with specific chirality. There are still great challenges in the control of the electrical conductivity and chirality of carbon nanotubes. The current control technology of the electrical conductivity of carbon nanotubes is mainly achieved by purification separation method and chemical doping method. The purification separation method includes molecular recognition technology, density gradient centrifugation method, cross electric field method and selective chemical reaction method, etc. The chemical doping method is to introduce dopants (such as nitrogen, boron, metal atoms, surface functional groups, etc.) into carbon nanotubes, which can change their electronic structure and thus control their electrical conductivity. The purification chirality and doping method generally have the problems of complicated 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.

[0003] It should be noted that the information disclosed in the above background section is only for understanding the background of the present application, and therefore can include information that does not constitute the prior art known to those of ordinary skill in the art. SUMMARY

[0004] The main purpose of the present application is to overcome the defects of the above background technology, and to provide a quasi-carbon nanotube structure and a manufacturing method thereof.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] A quasi-carbon nanotube structure, comprising a carbon nanotube or a carbon nanostrip, an axial linear defect being cut on the carbon nanotube, and a stable quasi-carbon nanotube structure containing the axial linear defect being formed by curling the carbon nanostrip; wherein the linear defect realizes the regulation of chirality and band gap width, so that the semiconducting chirality carbon nanostructure is converted into a metallic carbon nanostructure. Further, the conductive properties of the curled metallic carbon nanostrip structure are significantly improved by introducing a linear defect deconcentration state.

[0007] Further,

[0008] The diameter of the carbon nanotube is 0.8 to 30 nanometers.

[0009] The initial width of the carbon nanoribbon is 1 to 100 nanometers.

[0010] A method for manufacturing a quasi-carbon nanotube structure, comprising: cutting a carbon nanotube to form an axial linear defect by an atomic-scale manufacturing method, such as a plasma etching, ion beam etching or laser cutting method.

[0011] Further, the laser cutting method comprises:

[0012] Dispersing the carbon nanotube in a solvent;

[0013] Dropping or spraying the dispersed carbon nanotube solution on a clean substrate and drying it to form a uniformly distributed carbon nanotube film;

[0014] Cutting the carbon nanotube to form an axial linear defect by using a femtosecond laser or attosecond laser rapid cold cutting method.

[0015] A method for manufacturing a quasi-carbon nanotube structure, comprising: curling a carbon nanoribbon to form a stable quasi-carbon nanotube structure containing an axial linear defect by annealing the carbon nanoribbon in an electric field.

[0016] Further, curling the carbon nanoribbon to form a stable quasi-carbon nanotube structure containing an axial linear defect by annealing the carbon nanoribbon in an electric field, specifically comprises:

[0017] Preparation of a graphene ribbon substrate using photolithography technology;

[0018] Preparation of a graphene ribbon on the substrate by chemical vapor deposition method;

[0019] Removal of photoresist using an organic solvent;

[0020] Annealing in an electric field to curl the graphene ribbon to form a stable quasi-carbon nanotube structure containing an axial linear defect;

[0021] Preparation of the prepared quasi-carbon nanotube structure by peeling off from the substrate in an electrolytic manner.

[0022] Further, the substrate is a Cu substrate.

[0023] Further, the annealing in the electric field comprises: applying a strong electric field of 2.5-5 kV / m perpendicular to the substrate direction under vacuum conditions, heating the graphene ribbon containing the substrate to 1200-1300 K, and then annealing for 1-10 hours to make the curled nanobelt structure stable, and then slowly cooling to room temperature with the annealing device.

[0024] The present application has the following advantages:

[0025] The present application provides an innovative quasi-carbon nanotube structure and a manufacturing method thereof, 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 application can introduce axial linear defects without requiring the initial chirality of the carbon nanotube, realize the transition of the carbon nanotube from semiconductor to metal, effectively regulate the band gap width, and enhance the electrical conductivity. This transition is not only suitable for armchair, zigzag and other arbitrary chirality of carbon nanotube, but also significantly improves the electrical conductivity of carbon nanotube through the deconcentration state of the introduced linear defects. The present application provides a quasi-carbon nanotube structure and a curled nanobelt structure with high electrical conductivity, which is applied to carbon nanometer structure antennas and arrays in microwave, millimeter wave and terahertz wave bands, effectively solving the problems of low electrical conductivity and high impedance matching.

[0026] The present application has the following advantages:

[0027] Compared with the prior art, the present application has the following advantages and outstanding effects:

[0028] 1) Compared with the prior art, the present application has the following advantages and outstanding effects:

[0029] 2) Once the linear defects are introduced, the structure of the carbon nanotube changes little, and the electrical conductivity can be maintained for a long time and is not easy to degrade during use.

[0030] 3) Without considering the chirality of the carbon nanotube, the regulation process is simplified.

[0031] Other advantages of embodiments of the present application will be described in more detail in the following. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a schematic diagram of three structures of a complete carbon nanotube (a), a linear defect carbon nanotube (b) and a curvature carbon nanoribbon (c) according to embodiments of the present application.

[0033] Figure 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 (b) according to embodiments of the present application. DETAILED DESCRIPTION

[0034] The following detailed description of the application will be made with reference to the accompanying drawings. It should be emphasized that the following description is merely exemplary and is not intended to limit the scope of the application and its applications.

[0035] It should be noted that when an element is referred to as being "fixed" or "set" 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, the connection can be for fixing or for coupling or communicating.

[0036] It should be understood that the terms "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the embodiments of the present application and simplify the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0037] In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0038] Referring to Figure 1, the present application provides a quasi-carbon nanotube structure (see (b) of Figure 1), comprising a carbon nanotube, and an axial linear defect is cut on the carbon nanotube, wherein the linear defect realizes the regulation of chirality and band gap width, so that the semiconductor chiral carbon nanostructure is converted into a metallic carbon nanostructure.

[0039] In some embodiments, the method for preparing the quasi-carbon nanotube structure includes cutting the carbon nanotube to form axial linear defects by plasma etching, ion beam etching or laser cutting.

[0040] Referring to FIG. 1, another quasi-carbon nanotube structure (see (c) of FIG. 1) is provided by embodiments of the present application, which includes a carbon nanotube strip with axial linear defects cut thereon, and the carbon nanotube strip is rolled to form a quasi-carbon nanotube structure containing axial linear defects; wherein the linear defects realize the regulation of chirality and band gap width, so that the semiconductor chiral carbon nanotube structure is converted into a metallic carbon nanotube structure. Further, the conductive properties of the rolled metallic carbon nanotube strip structure are significantly improved by introducing the linear defect deconfinement state.

[0041] In some embodiments, the method for preparing the quasi-carbon nanotube structure includes annealing the carbon nanotube strip in an electric field to roll the carbon nanotube strip to form a stable quasi-carbon nanotube structure containing axial linear defects.

[0042] The specific embodiments of the present application are further described below.

[0043] The two quasi-carbon nanotube structures of embodiments of the present application have structures as shown in (b) and (c) of FIG. 1, containing 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 nanotube is occupied by a large number of electronic states, and the carbon nanotube is converted from a semiconductor to a metallic conductor. The deconfinement state of the linear defect introduced by the quasi-carbon nanotube structure can greatly improve the conductive properties of the carbon nanotube. The present application is applicable to but not limited to the conductive property regulation of armchair, zigzag and other various chiral state carbon nanotubes.

[0044] The quasi-carbon nanotube structure introduces linear defects to form a carbon nanotube with axial openings. Due to the deconfinement of the suspended electrons, the energy level of the electrons near the Fermi surface in the material band structure is increased, resulting in good conductivity of the carbon nanotube regardless of its chirality. Therefore, the present application does not need to consider chirality, and the axial linear defects not only can convert a semiconductor carbon nanotube into a metallic carbon nanotube, but also can enhance the conductive properties of the metallic carbon nanotube.

[0045] In some embodiments, a method for preparing a quasi-carbon nanotube structure to improve the conductivity of carbon nanotube materials and structures includes the following steps:

[0046] 1) Preparing carbon nanotubes: carbon nanotubes with a diameter of 0.8 to 30 nanometers are selected as the initial material.

[0047] 2) Linear defect etching:

[0048] The linear defects are introduced into the carbon nanotube, and the linear defects can be realized by plasma etching, ion beam etching or laser cutting, etc. During the etching process, the density and distribution of the defects are adjusted by precisely controlling the etching parameters (such as time, temperature, gas concentration, etc.).

[0049] Thus, the quasi-carbon nanotube structure with axial linear defects forms a carbon tube with new electronic properties, which has good conductivity.

[0050] In some embodiments, another method for manufacturing a quasi-carbon nanotube structure is provided to improve the conductivity of carbon nanotube materials and structures, which comprises the following steps:

[0051] 1) Prepare carbon nanostrips: select carbon nanostrips with a width of 1 to 100 nanometers as the initial material.

[0052] 2) Anneal the carbon nanostrips in an electric field to make the carbon nanostrips curl and form a stable quasi-carbon nanotube structure with axial linear defects.

[0053] Thus, the carbon nanostrips with curvature are curled into quasi-carbon nanotube structures with axial linear defects, forming carbon tubes with new electronic properties, which have good conductivity.

[0054] The quasi-carbon nanotube structure of the present application introduces linear defects into the carbon nanotube or curls the carbon nanostrips to form a quasi-carbon nanotube structure with linear defects, realizing the regulation of chirality and band gap width. The present application does not need to consider the chirality of the initial quasi-carbon nanotube structure, and can convert semiconductor chiral carbon nanotubes into metallic carbon nanotube structures through atomic-level operation or atomic-level manufacturing technology, realizing the regulation of chirality and band gap width. The deconfinement state of the introduced linear defects can greatly improve the conductivity of carbon nanotube materials and structures. The present application can improve the conductivity and field emission performance of carbon nanotubes.

[0055] Example 1

[0056] Laser cutting method for cutting and manufacturing quasi-carbon nanotube structure containing linear defects

[0057] 1) Disperse nanotubes: disperse the carbon nanotubes in a solvent (ethanol, isopropanol, water, etc.) to avoid agglomeration.

[0058] 2) Prepare the substrate: drop or spray the dispersed carbon nanotube solution on a clean substrate (such as a silicon wafer, a glass sheet, etc.) to dry it to form a uniform distribution of carbon nanotube film.

[0059] 3) Laser cutting process: Choose a femtosecond laser, precisely position the area of carbon nanotubes that needs to be cut through a microscope or other imaging device. Control the movement path of the laser beam on the sample surface, make it scan along the predetermined trajectory and cut the carbon nanotubes. Due to the local heating of the laser beam on the carbon nanotubes, it causes the material to vaporize or break, thus achieving cutting. Avoid excessive damage to the adjacent area during cutting.

[0060] 4) Characterization of cutting effect: After cutting, clean the sample to remove debris and impurities generated during the cutting process. Use a microscope (such as a scanning electron microscope SEM, transmission electron microscope TEM) to characterize the cutting effect. At this time, the carbon nanotubes have different sizes of linear defects, and the linear defects introduce a large number of dangling electrons, making the carbon nanotubes change from semiconductor to metal conductor.

[0061] Example 2

[0062] Curvature carbon nanobelt method for making quasi-carbon nanotube structure containing linear defects

[0063] 2) Use photolithography technology to prepare Cu substrate, define the width and length of graphene strip. Through the steps of photoresist coating, pattern exposure and development, prepare a graphene strip substrate with a width of 5-40 nm.

[0064] 3) Use chemical vapor deposition method to prepare graphene strip on copper substrate.

[0065] 4) Use organic solvent to remove photoresist.

[0066] 5) Under vacuum conditions, apply a strong electric field perpendicular to the substrate direction of 2.5-5 kV / m, and heat the graphene strip containing the substrate to 1200-1300 K. Due to the effect of electric field and heating, the graphene carbon nanobelt will curl 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.

[0067] 6) Use electrolysis to exfoliate carbon nanotubes.

[0068] In summary, the present application proposes an innovative quasi-carbon nanotube structure and its manufacturing method, which breaks through the limitations of traditional technology and provides a simple, efficient and easy-to-control solution to regulate the electrical conductivity of carbon nanotubes. The present application can introduce axial linear defects without considering the initial chirality of carbon nanotubes through atomic-level operation or atomic-level manufacturing technology, realize the transition of carbon nanotubes from semiconductor to metal, and effectively regulate the band gap width. This transition is not only suitable for armchair, zigzag and other arbitrary chirality states of carbon nanotubes, but also significantly improves the electrical conductivity of carbon nanotubes through the deconcentration state of the introduced linear defects.

[0069] Overall, the present application not only improves the conductivity and field emission performance of carbon nanotubes, but also provides a new mechanism and means for the electronic property regulation of carbon nanotubes.

[0070] Compared with the prior art, the present application has the following advantages and outstanding effects:

[0071] 1) Compared with the prior art, the present application has flexible implementation methods, is compatible with various manufacturing processes, does not need to greatly change the production process, and is helpful for large-scale application and production.

[0072] 2) Once the linear defects are introduced, the structure of the carbon nanotube changes little, and the conductivity can be maintained for a long time, and degradation is not easy to occur during use.

[0073] 3) The chirality of the carbon nanotube does not need to be considered, and the regulation process is simplified.

[0074] The above is a further detailed description of the present application in combination with specific / preferred embodiments, and cannot be considered as limiting the specific implementation of the present application to these descriptions. For ordinary skilled persons in the technical field to which the present application belongs, without departing from the concept of the present application, they can make several substitutions or modifications to the described embodiments, and these substitutions or modifications should be considered as belonging to the protection scope of the present application. In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "preferred embodiment", "example", "specific example", 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 application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In the case of not contradicting each other, the skilled person in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples. Although the embodiments of the present application 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 the patent application.

Claims

1. A quasi-carbon nanotube structure, characterized by, The carbon nanotube or carbon nanoribbon includes an axial linear defect formed by atomic-scale cutting, and the carbon nanoribbon is curled to form a stable quasi-carbon nanotube structure containing the axial linear defect; wherein the linear defect realizes chiral transformation and band gap width regulation, so that the semiconductor chiral carbon nanostructure is transformed into a metallic carbon nanostructure.

2. A method of fabricating a quasi-carbon nanotube structure, comprising: The carbon nanotube or carbon nanoribbon includes an axial linear defect formed by atomic-scale cutting, and the carbon nanoribbon is curled to form a stable quasi-carbon nanotube structure containing the axial linear defect; wherein the linear defect realizes chiral transformation and band gap width regulation, so that the semiconductor chiral carbon nanostructure is transformed into a metallic carbon nanostructure. The atomic-scale manufacturing method includes any one of plasma etching, ion beam etching, femtosecond or attosecond laser rapid cold cutting method.

3. The method for fabricating the quasi-carbon nanotube structure as described in claim 2, characterized in that, The atomic-scale manufacturing method includes any one of plasma etching, ion beam etching, femtosecond or attosecond laser rapid cold cutting method.

4. The method for fabricating the quasi-carbon nanotube structure as described in claim 2, characterized in that, The atomic-scale manufacturing method includes any one of plasma etching, ion beam etching, femtosecond or attosecond laser rapid cold cutting method. The carbon nanotube is dispersed in a solvent; The dispersed carbon nanotube solution is drop-casted or spray-casted on a clean substrate and dried to form a uniform distribution of carbon nanotube film; The carbon nanotube is cut to form an axial linear defect using a femtosecond or attosecond laser rapid cold cutting method.

5. A method of fabricating a quasi-carbon nanotube structure, comprising: The carbon nanotube or carbon nanoribbon includes an axial linear defect formed by atomic-scale cutting, and the carbon nanoribbon is curled to form a stable quasi-carbon nanotube structure containing the axial linear defect; wherein the linear defect realizes chiral transformation and band gap width regulation, so that the semiconductor chiral carbon nanostructure is transformed into a metallic carbon nanostructure. The method specifically includes: A graphene ribbon substrate is prepared using a photolithography technique; A graphene ribbon is prepared on the substrate by chemical vapor deposition; The photoresist is removed using an organic solvent; The graphene ribbon is annealed in an electric field to curl and form a stable quasi-carbon nanotube structure containing an axial linear defect; the annealing in the electric field includes: under high vacuum conditions, applying a strong electric field of 2.5-5kV / m perpendicular to the substrate direction, heating the graphene ribbon containing the substrate to 1200K-1300K, and then annealing for 1 to 10 hours to make the curled nanoribbon reach structural stability, and then slowly cooling to room temperature with the annealing equipment; The prepared quasi-carbon nanotube structure is peeled off from the substrate by electrolysis. The substrate is a Cu substrate.

6. The method for fabricating the quasi-carbon nanotube structure as described in claim 5, characterized in that, ​

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