CN116462186A - Monochiral and close-packed carbon tube array thin film and its preparation method - Google Patents

Abstract

The invention provides a single-chiral and densely packed carbon tube array film and a preparation method thereof. The film comprises: a plurality of single-walled carbon tubes arranged in parallel; wherein, the diameter of the single-walled carbon tubes is 1 nm to 2 nm; and the distance between two adjacent single-walled carbon tubes is 0.3 nm to 0.4 nm. The area of the carbon tube array thin film of the present invention can be selected arbitrarily; the performance is excellent, the carrier mobility is greater than 4000cm ² V ^‑1 S ^‑1 , the on-state current density is greater than 1mA/μm, and the current carrying capacity is greater than 8mA/μm; the preparation method is simple to operate, low in cost and can be produced on a large scale.

Description

Monochiral and close-packed carbon tube array thin film and its preparation method

technical field

The invention belongs to the technical field of nanometer materials, and in particular relates to a monochiral and densely arranged carbon tube array film and a preparation method thereof.

Background technique

Single-walled carbon nanotubes (SWCNTs) have a unique one-dimensional hollow tubular structure and excellent performance. Its wide-spectrum response and high light absorption coefficient make it one of the material foundations for future carbon-based high-performance devices. Its unique one-dimensional hollow tubular structure enables it to have excellent electrical, thermal, and mechanical properties. However, the prerequisite for the widespread application of carbon nanotubes in electronic devices is to realize their macro-controllable preparation.

At the beginning of this century, SWCNTs were mainly based on CVD-grown single carbon tubes for the demonstration of field effect transistors. At that time, the main problem to be solved was how to improve the device quality of single carbon tubes, such as using metals with different work functions as contacts. After the contact problem was solved, researches on the preparation of large-scale devices based on carbon tube films gradually increased. However, since the orientation of carbon tubes in carbon tube films greatly affects the performance of carbon tube devices, only when the carbon tubes in the device channel are completely parallel can the device achieve optimal performance. Then began to work on obtaining thin films based on parallel arrangement of carbon tubes. At present, it is mainly achieved through the following two paths: one is to grow carbon tube films directly on the substrate; the other is to assemble independent carbon tubes into aligned films through a series of post-processing methods. In technical applications, each transistor requires several parallel single-walled carbon tube channels. In order to surpass the performance of silicon-based complementary metal-oxide semiconductor (Si-CMOS), Patil et al. predicted that the single-walled carbon tube density must be greater than 250 tubes per square micron. In addition, fields such as radio frequency applications, plastic electronics, display technology, sensors, and electrodes also require high-density massively parallel arrays of single-walled carbon tubes. The ideal carbon tube film should be a single-chiral, fully aligned close-packed single-walled carbon tube array film. The ideal carbon tube film can even be called a carbon tube crystal, but this perfect carbon tube film has not yet been controllably prepared.

Contents of the invention

In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a single-chiral and closely-packed carbon tube array film and its preparation method, which is used to solve the problems in the prior art that there is no large-scale single-chiral, fully aligned close-packed single-wall carbon tube array film and its preparation method.

In order to achieve the above purpose and other related purposes, the present invention provides a single-chiral and densely packed carbon tube array film, the carbon tube array film comprising: a number of single-walled carbon tubes arranged in parallel; wherein,

The diameter of the single-walled carbon tube is 1 nm to 2 nm;

The distance between two adjacent single-walled carbon tubes is 0.3nm-0.4nm.

Optionally, the carbon tube array film is grown on an atomically flat substrate, and the distance between the carbon tube array film and the atomically flat substrate is 0.3 nm˜0.5 nm.

Further, the substrate with atomic level flatness is a hexagonal boron nitride substrate or a graphite substrate.

The present invention also provides a method for preparing a single-chiral and closely-packed carbon tube array film, which is used to prepare the above-mentioned single-chiral and close-packed carbon tube array film. The preparation method includes the following steps:

Provides substrates with atomic-level flatness;

Evaporating metal nano-catalyst particles on the surface of the substrate;

Place the substrate on which the metal nano-catalyst particles are vapor-deposited in a furnace tube for heating, and feed a carbon source gas of methane, acetylene or ethanol to grow a monochiral and densely packed carbon tube array film on the substrate; wherein the growth temperature is 600° C. to 1200° C., and the growth time of keeping the growth temperature constant is more than 30 minutes. During the growth process, hydrogen is introduced as a gas to maintain the activity of the metal nano-catalyst particles; The flow ratio is greater than 10:1; when the carbon source gas is acetylene, the flow ratio of the carbon source gas to the hydrogen is greater than 1:2 during the growth process;

Turn off the carbon source gas, and cool down to room temperature under the action of protective gas.

Optionally, the atomically flat substrate is a hexagonal boron nitride substrate or a graphite substrate.

Optionally, the metal nano-catalyst particles are iron nano-catalyst particles, cobalt nano-catalyst particles or nickel nano-catalyst particles, and the diameter of the metal nano-catalyst particles is 1 nm to 10 nm.

Further, the step of growing a monochiral and densely packed carbon tube array film on the substrate includes:

A quartz tube furnace is provided, and the substrate evaporated with a metal nanocatalyst film is placed in the quartz tube furnace, wherein the thickness of the metal nanocatalyst film is

Heating process: pass hydrogen and argon protective gas into the quartz tube furnace, and raise the temperature for 10 minutes to 20 minutes to the growth temperature, so that the metal nanocatalyst film is formed into the metal nanocatalyst particles;

Growth process: stop feeding the argon gas during the heating process, keep the flow rate of the hydrogen gas and the growth temperature constant during the heating process, and feed the carbon source gas into the quartz tube furnace, the flow rate of the carbon source gas is the same as the flow rate of the argon gas during the heating process;

Cooling process: after the growth is completed, the carbon source gas is turned off, and the hydrogen and argon protective gas are continuously fed in. The flow rates of the hydrogen and argon are the same as those in the heating process, and the temperature is naturally cooled to room temperature.

Further, the substrate with atomic-level flatness is a hexagonal boron nitride substrate; the metal nanocatalyst particles are cobalt nanocatalyst particles, and the thickness of the metal nanocatalyst film is The flow rate of the hydrogen gas in the heating process is 200 SCCM, the flow rate of the argon gas is 100 SCCM, and the air pressure is kept at 10 Pa during the heating process; the carbon source gas is acetylene, and the air pressure is kept at 10 Pa during the growth process, the growth time is 60 min, and the growth temperature is 700 ° C.

Optionally, the substrate with atomic-level flatness is a hexagonal boron nitride substrate; the metal nanocatalyst particles are iron nanocatalyst particles, and the thickness of the metal nanocatalyst film is The flow rate of the hydrogen gas during the heating process is 40 SCCM, the flow rate of the argon gas is 400 SCCM, and the air pressure is kept at 1 standard atmosphere during the heating process; the carbon source gas is methane, the air pressure is kept at 1 standard atmosphere during the growth process, the growth time is 60 minutes, and the growth temperature is 850 ° C.

Optionally, the substrate with atomic-level flatness is a graphite substrate; the metal nanocatalyst particles are cobalt nanocatalyst particles, and the thickness of the metal nanocatalyst film is The flow rate of the hydrogen gas in the heating process is 200 SCCM, the flow rate of the argon gas is 100 SCCM, and the air pressure is kept at 10 Pa during the heating process; the carbon source gas is acetylene, and the air pressure is kept at 10 Pa during the growth process, the growth time is 60 min, and the growth temperature is 700 ° C.

As mentioned above, the present invention provides a single-chiral and densely packed carbon tube array film and a preparation method thereof. The area of the carbon tube array film can be selected arbitrarily; the performance is excellent, the carrier mobility is greater than 4000 cm ² V ^-1 S ^-1 , the on-state current density is greater than 1 mA/μm, and the current carrying capacity is greater than 8 mA/μm; the preparation method is simple to operate, low in cost and can be mass-produced.

Description of drawings

Fig. 1 shows a schematic diagram of the structure of the growth device used for the preparation of the monochiral and densely packed carbon tube array thin film of the present invention.

FIG. 2 shows a schematic diagram of a three-dimensional structure of a monochiral and densely packed carbon tube array film as an example of the present invention.

FIG. 3 is a schematic diagram showing an enlarged structure of a single-chiral and close-packed carbon tube array thin film of another example of the present invention.

Fig. 4 shows an atomic force microscope picture of a carbon tube array film prepared by the method for preparing a single-chiral and close-packed carbon tube array film of the present invention.

Component designation description

10 single wall carbon tube

11 Carbon tube array film

12 substrate

13 Metal Nanocatalyst Particles

14 tube furnace

15 furnace tube

16 carbon source gas

Detailed ways

Embodiments of the present invention are described below through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation modes, and various modifications or changes can be made to the details in this specification based on different viewpoints and applications without departing from the spirit of the present invention.

For example, when describing the embodiments of the present invention in detail, for the convenience of explanation, the cross-sectional view showing the device structure will not be partially enlarged according to the general scale, and the schematic diagram is only an example, which should not limit the protection scope of the present invention. In addition, the three-dimensional space dimensions of length, width and depth should be included in actual production.

For convenience of description, spatial relationship words such as "below", "below", "below", "below", "above", "on" etc. may be used herein to describe the relationship between one element or feature and other elements or features shown in the drawings. It will be understood that these spatially relative terms are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the figures. In addition, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present. As used herein, "between" means that both endpoints are inclusive.

In the context of this application, structures described as having a first feature "on top of" a second feature may include embodiments where the first and second features are formed in direct contact, and may also include embodiments where additional features are formed between the first and second features such that the first and second features may not be in direct contact.

Embodiment one

See Figures 1 through 4. It should be noted that the diagrams provided in this embodiment are only schematically illustrating the basic idea of the present invention, so that only the components related to the present invention are shown in the diagrams rather than drawn according to the number, shape and size of the components in actual implementation. The type, quantity and proportion of each component in actual implementation can be changed arbitrarily, and the layout of the components may also be more complicated.

As shown in Figure 2 and Figure 3, the present embodiment provides a single-chiral and closely packed carbon tube array film, the carbon tube array film 11 includes: a number of single-walled carbon tubes 10 arranged in parallel (as shown in Figure 2); wherein,

The diameter D of the single-walled carbon tube 10 is 1nm-2nm, for example, it can be 1nm, 1.5nm or 2nm, etc.;

The distance L1 between two adjacent single-walled carbon tubes 10 is 0.3nm-0.4nm, for example, 0.3nm, 0.33nm or 0.4nm, etc., where L1 refers to the minimum distance between two adjacent single-walled carbon tubes 10 .

It should be noted here that the single-walled carbon tubes 10 in the carbon tube array film 11 can be straight tubes or bent tubes, for example, the single-walled carbon tubes 10 in FIG.

The single-chiral and closely-packed carbon tube array film of this embodiment can be of any size, which is selected according to actual needs, and the carrier mobility of the semiconductor device prepared by using the single-chiral and close-packed carbon tube array film of this embodiment is greater than 4000 cm ² V ^-1 S ^-1 , the on-state current density is greater than 1 mA/μm, and the current carrying capacity is greater than 8 mA/μm, and the performance is very excellent.

As shown in Figure 2 and Figure 3, as a preferred example, the carbon tube array film 11 is grown on the substrate 12 of atomic level flatness, and the distance L2 between the carbon tube array film 11 and the described substrate 12 of atomic level flatness is 0.3nm～0.5nm, for example, can be 0.3nm, 0.4nm or 0.5nm etc., here L2 refers to the minimum distance between the two, which is defined by the range between the carbon tube array film 11 and the described substrate 12 of atomic level flatness Determined by the equilibrium position of the De Waals force, the mechanism of using the atomic-level flatness substrate 12 as the growth substrate of the carbon tube array film 11 is: there is a super-lubricating effect between the carbon nanotubes and the atomic-level flatness substrate, and the carbon nanotubes grown on it can slide freely on the substrate, and then find the state with the lowest energy, and finally stack into a regular densely packed carbon tube array. As a more preferred example, the substrate 12 with atomic-level flatness is a hexagonal boron nitride substrate or graphite substrate, which is easy to form a better superlubricating effect with the single-wall carbon tube 10, that is, the frictional resistance between the single-wall carbon tube 10 and the substrate 12 is extremely low, and because there is a van der Waals attraction between the single-wall carbon tube 10 and the single-wall carbon tube 10, so the single-wall carbon tube 10 and the single-wall carbon tube 10 will be spontaneously adsorbed together on the surface of the atomically flat substrate 12 without resistance, thereby forming a single Chiral carbon tubes, close-packed carbon tube films.

Embodiment two

This embodiment provides a method for preparing a single-chiral and closely-packed carbon tube array thin film. This preparation method can be used to prepare the single-chiral and closely-packed carbon tube array thin film described in the first embodiment above. For the effect of the prepared carbon tube array thin film, please refer to the first embodiment above, and will not be repeated below. The preparation method comprises the following steps:

Provides substrates with atomic-level flatness;

Evaporating metal nano-catalyst particles on the surface of the substrate;

Place the substrate on which the metal nanocatalyst particles are vapor-deposited in a furnace tube for heating, and feed a carbon source gas of methane, acetylene or ethanol to grow a monochiral and densely packed carbon tube array film on the substrate; wherein the growth temperature is 600° C. to 1200° C., and the growth time is not less than 30 minutes while maintaining the growth temperature. The flow ratio of the carbon source gas is greater than 10:1; when the carbon source gas is acetylene, the flow ratio of the carbon source gas to the hydrogen gas during the growth process is greater than 1:2;

Turn off the carbon source gas, and cool down to room temperature under the action of protective gas.

采用本实施例的碳管阵列薄膜的制备方法中薄膜的形成机理为：当单壁碳管在原子级平整度的衬底表面生长时，碳管与衬底之间形成超润滑效应，即碳管与衬底的摩擦阻力极低，所以碳管可以在衬底上任意滑动，进而找到其能量最低的状态，又因为碳管与碳管之间存在范德华吸引力，所以碳管与碳管会在原子级平整的衬底表面无阻力地自发吸附到一起，从而形成单一手性碳管、密排碳管薄膜，且薄膜面积可达到10μm×1μm，载流子迁移率大于4000cm ² V ^-1 S ^-1 ，开态电流密度大于1mA/μm，电流承载能力大于8mA/μm，性能非常优异。 During the growth process of the carbon tube array film, hydrogen is introduced to keep the metal nano catalyst particles active, and a carbon source gas with a relatively high carbon source ratio of methane or acetylene or ethanol is used. For example, the flow ratio of methane to hydrogen is greater than 10:1, or the flow ratio of acetylene to hydrogen is greater than 2:1. The metal nano catalyst particles will dissolve the carbon source and precipitate single-walled carbon nanotubes. In addition, the preparation method is simple to operate, low in cost, and can be produced on a large scale; finally, the preparation method of this embodiment can form a carbon tube array film of any size. .

As shown in FIG. 1 to FIG. 4 , the preparation method of this embodiment will be described in detail below with reference to the accompanying drawings.

As shown in FIG. 1 , step S1 is first performed to provide a substrate 12 with atomic level flatness.

As an example, the substrate 12 may be a hexagonal boron nitride substrate or a graphite substrate. Specifically, based on the existing methods for preparing hexagonal boron nitride and graphite, mechanical exfoliation is generally used. When a hexagonal boron nitride substrate or graphite substrate is used in this embodiment, the hexagonal boron nitride substrate or graphite substrate can be bonded to a silicon wafer by mechanical exfoliation. In this application, hexagonal boron nitride and graphite are preferred substrates for growing carbon tube array films, but they are not limited thereto. Other substrate materials with atomic-level flatness are also suitable as substrates in this embodiment. Using an atomic-level flat substrate as the growth substrate of the carbon tube array film can form a superlubricating effect between the two during the growth of carbon tubes, combined with the van der Waals attraction between carbon tubes and carbon tubes, so that the formed carbon tube array film becomes a single-chiral and close-packed form.

As shown in FIG. 1 , step S2 is then performed to vapor-deposit metal nano-catalyst particles 13 on the surface of the substrate 12 .

As an example, the metal nano-catalyst particles 13 are selected as iron nano-catalyst particles, cobalt nano-catalyst particles or nickel nano-catalyst particles. Preferably, the metal nano-catalyst particles 13 have a diameter of 1nm-10nm, such as 1nm, 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm and so on. The metal nano-catalyst particles 13 are subsequently used as a dissolving agent for the carbon source gas 16 during the carbon tube growth process, so as to precipitate the single-walled carbon tubes 10 .

As a specific example, at first on the surface of the substrate 12 vapor-deposited metal nano-catalyst film, the thickness of the metal nano-catalyst film is , for example /> or etc.; then the substrate 12 evaporated with the metal nanocatalyst film is placed in the furnace tube 15 of the tube furnace 14 to carry out the heating process. During the heating process, hydrogen and argon protective gas are introduced into the furnace tube 15, and the temperature is raised for 10min to 20min to the required growth temperature of the subsequent carbon tube array film. During the heating process, the metal nanocatalyst film can be agglomerated, thereby forming the metal nanocatalyst particles 13.

As an example, the tube furnace 14 is in the form of a heating furnace outside the furnace tube 15, which can provide good sealing, insulation box and temperature control stability. During the heating process, the substrate 12 is placed in the furnace tube 15 to carry out the heating process. Preferably, the furnace tube 15 is a quartz furnace tube.

In the heating process, hydrogen and argon are introduced into the furnace tube 15 as protective gases, and can also be used as reducing gases to reduce oxidized metal nanocatalyst particles and some carbon-containing impurity substances generated by the carbon source gas 16 during the subsequent high-temperature growth process, and the flow rate of the carbon source gas 16 introduced during the growth process is the same as the flow rate of the argon gas during the heating process, so as to ensure the stability of the total gas flow rate during the growth process and the growth quality of the carbon tube array film.

As shown in Figures 1 and 4, proceed to step S3, place the substrate 12 with the metal nanocatalyst particles 13 evaporated in a furnace tube 15 for heating, and pass into a carbon source gas 16 of methane or acetylene or ethanol to grow a single chiral and densely packed carbon tube array film 11 on the substrate 12; wherein the growth temperature is 600 ° C to 1200 ° C, and the growth time for maintaining the growth temperature is not less than 30 minutes. 13 active gas; when the carbon source gas 16 is methane, the flow ratio of the carbon source gas 16 to the hydrogen gas is greater than 10:1 during the growth process; when the carbon source gas 16 is acetylene, the flow ratio of the carbon source gas 16 to the hydrogen gas is greater than 1:2 during the growth process.

As a specific example, when the above-mentioned heating process is over, the growth process is started, that is, the heating process and the growth process are completed in the same tube furnace 14, and it is a continuous process. In this process, the argon gas in the heating process is stopped, and the flow rate of the hydrogen gas and the growth temperature are kept constant during the heating process, and the carbon source gas 16 is introduced into the tube furnace 14, that is, the furnace tube 15. The flow rate of the carbon source gas 16 is the same as the flow rate of the argon gas in the heating process to ensure the growth process. The stability of the total gas flow in the medium ensures the growth quality of the carbon tube array film.

Finally, step S4 is performed, the carbon source gas 16 is turned off, and the temperature is lowered to room temperature under the action of the protective gas.

As a specific example, in the cooling process, after the carbon source gas 16 is closed, the hydrogen gas and the argon protective gas are continuously introduced, and the flow rates of the hydrogen gas and the argon gas are the same as those in the heating process, and the temperature is naturally lowered to room temperature, which also ensures the stability of the overall gas flow rate in the entire cooling process.

The preparation method of the monochiral close-packed carbon tube array thin film of this embodiment will be further described through specific experimental examples below.

Experimental example 1

1) Take a silicon wafer and cut it into small pieces with a size of about 1cm×1cm.

2) Take a hexagonal boron nitride crystal, and prepare a hexagonal boron nitride thin slice on the above-mentioned silicon wafer by mechanical peeling method, as the substrate 12 with atomic level flatness.

3) Evaporate on the surface of the above-mentioned substrate 12 by adopting the method of thermal evaporation coating thickness of cobalt film, as the growth catalyst film.

4) Place the above-mentioned substrate 12 coated with the catalyst thin film in a quartz tube furnace. During the heating process, the gas atmosphere in the furnace is hydrogen gas with a flow rate of 200 SCCM and argon gas with a flow rate of 100 SCCM. The heating process is about 15 minutes, gradually rising from room temperature to the growth temperature of 700° C., and the pressure is maintained at 10 Pa during the heating process.

5) When the temperature reaches the target growth temperature of 700°C, stop feeding the argon gas. On the basis of keeping the original hydrogen gas at a flow rate of 200 SCCM, then feed 100 SCCM of acetylene gas as the growth gas. The growth time is 60 minutes, and the pressure is kept at 10 Pa during the growth process.

6) After the growth is over, turn off the acetylene gas, feed hydrogen at a flow rate of 200 SCCM and argon at a flow rate of 100 SCCM, cool down to room temperature naturally, and then take out the sample.

7) The size of the carbon tube array thin film 11 can reach 10 μm×1 μm through the characterization of the scanning electron microscope and the atomic force microscope.

Experimental example 2

1) Take a silicon wafer and cut it into small pieces with a size of about 1cm×1cm.

2) Take a hexagonal boron nitride crystal, and prepare a hexagonal boron nitride thin slice on the above-mentioned silicon wafer by mechanical peeling method, as the substrate 12 with atomic level flatness.

3) Evaporate on the surface of the above-mentioned substrate 12 by adopting the method of thermal evaporation coating Thickness of the iron film, as the growth catalyst film.

4) Place the above-mentioned substrate 12 coated with the catalyst thin film in a quartz tube furnace. During the heating process, the gas atmosphere in the furnace is hydrogen, with a flow rate of 40 SCCM and argon gas, and two gases with a flow rate of 400 SCCM. The heating process takes about 15 minutes, gradually rising from room temperature to the growth temperature of 850° C., and maintaining the pressure at 1 standard atmosphere during the heating process.

5) When the temperature reaches the target growth temperature of 850°C, stop feeding the argon gas. On the basis of keeping the original hydrogen gas at a flow rate of 40 SCCM, add 400 SCCM methane gas as the growth gas. The growth time is 60 minutes, and the pressure is kept at 1 standard atmospheric pressure during the growth process.

6) After the growth is over, turn off the methane gas, feed in hydrogen at a flow rate of 40 SCCM and argon at a flow rate of 400 SCCM, cool down to room temperature naturally, and then take out the sample.

7) The size of the carbon tube array thin film 11 can reach 10 μm×1 μm through the characterization of the scanning electron microscope and the atomic force microscope.

Experimental example 3

This experimental example is basically the same as the experimental example 1, except that the substrate 12 of the atomic level flatness in this experimental example is graphite, and other steps are the same as the experimental example 1. The dimensions of the carbon tube array thin film 11 obtained in this experimental example are 2 μm×50 nm through scanning electron microscopy and atomic force microscopy.

In summary, the present invention provides a single-chiral and densely packed carbon tube array film and a preparation method thereof. The area of the carbon tube array film can be selected arbitrarily; the performance is excellent, the carrier mobility is greater than 4000 cm ² V ^-1 S ^-1 , the on-state current density is greater than 1 mA/μm, and the current carrying capacity is greater than 8 mA/μm; the preparation method is simple to operate, low in cost, and can be mass-produced. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial application value.

The above-mentioned embodiments only illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed in the present invention should still be covered by the claims of the present invention.

Claims (10)

1. A single chiral and closely spaced carbon tube array film, the carbon tube array film comprising: a plurality of single-wall carbon tubes arranged in parallel; wherein,,

the diameter of the single-wall carbon tube is 1 nm-2 nm;

the interval between two adjacent single-wall carbon tubes is 0.3 nm-0.4 nm.

2. The single chiral and close packed carbon tube array film of claim 1, wherein the carbon tube array film is grown on an atomically flat substrate and the spacing between the carbon tube array film and the atomically flat substrate is 0.3nm to 0.5nm.

3. The single chiral and closely spaced carbon tube array film of claim 2, wherein: the substrate with atomic-level flatness is a hexagonal boron nitride substrate or a graphite substrate.

4. A method for preparing the single chiral and close packed carbon tube array film according to any one of claims 1 to 3, wherein the method comprises the steps of:

providing a substrate with atomic-level flatness;

evaporating metal nano catalyst particles on the surface of the substrate;

placing the substrate evaporated with the metal nano catalyst particles in a furnace tube for heating, and introducing carbon source gas of methane or acetylene or ethanol to grow a single chiral and closely arranged carbon tube array film on the substrate; wherein the growth temperature is 600-1200 ℃, the growth time for keeping the growth temperature unchanged is longer than 30min, and hydrogen is introduced in the growth process as the gas for keeping the activity of the metal nano catalyst particles; when the carbon source gas is methane, the flow ratio of the carbon source gas to the hydrogen in the growth process is greater than 10:1; when the carbon source gas is acetylene, the flow ratio of the carbon source gas to the hydrogen in the growth process is greater than 1:2;

and closing the carbon source gas, and cooling to room temperature under the action of the protective gas.

5. The method for preparing the single chiral and closely spaced carbon tube array film according to claim 4, wherein the method comprises the following steps: the substrate with atomic-level flatness is a hexagonal boron nitride substrate or a graphite substrate.

6. The method for preparing the single chiral and closely spaced carbon tube array film according to claim 4, wherein the method comprises the following steps: the metal nano catalyst particles are iron nano catalyst particles or cobalt nano catalyst particles or nickel nano catalyst particles, and the diameter of the metal nano catalyst particles is 1 nm-10 nm.

7. The method of claim 6, wherein the step of growing a single chiral and close packed carbon tube array film on the substrate comprises:

providing a quartz tube furnace, and placing the substrate evaporated with the metal nano catalyst film in the quartz tube furnace, wherein the thickness of the metal nano catalyst film is as follows

And (3) heating: introducing hydrogen and argon shielding gas into the quartz tube furnace, and heating for 10-20 min to the growth temperature so as to form the metal nano catalyst thin film into the metal nano catalyst particles;

the growth process comprises the following steps: stopping introducing the argon in the heating process, keeping the flow of the hydrogen and the growth temperature unchanged in the heating process, and introducing the carbon source gas into the quartz tube furnace, wherein the flow of the carbon source gas is the same as the flow of the argon in the heating process;

and (3) a cooling process: and after the growth is finished, closing the carbon source gas, continuously introducing the hydrogen and the argon shielding gas, wherein the flow rates of the hydrogen and the argon are the same as those in the heating process, and naturally cooling to room temperature.

8. The method for preparing the single chiral and closely spaced carbon tube array film according to claim 7, wherein the method comprises the steps of: the substrate with the atomic-level flatness is a hexagonal boron nitride substrate; the saidThe metal nano catalyst particles are cobalt nano catalyst particles, and the thickness of the metal nano catalyst film is as followsThe flow of the hydrogen is 200SCCM in the heating process, the flow of the argon is 100SCCM, and the air pressure is kept to be 10pa in the heating process; the carbon source gas is acetylene, the air pressure is kept at 10pa in the growth process, the growth time is 60min, and the growth temperature is 700 ℃.

9. The method for preparing the single chiral and closely spaced carbon tube array film according to claim 7, wherein the method comprises the steps of: the substrate with the atomic-level flatness is a hexagonal boron nitride substrate; the metal nano catalyst particles are iron nano catalyst particles, and the thickness of the metal nano catalyst film is as followsThe flow of the hydrogen is 40SCCM in the heating process, the flow of the argon is 400SCCM, and the air pressure is kept to be 1 standard atmosphere in the heating process; the carbon source gas is methane, the air pressure is kept at 1 standard atmosphere in the growth process, the growth time is 60min, and the growth temperature is 850 ℃.

10. The method for preparing the single chiral and closely spaced carbon tube array film according to claim 7, wherein the method comprises the steps of: the substrate with atomic-level flatness is a graphite substrate; the metal nano catalyst particles are cobalt nano catalyst particles, and the thickness of the metal nano catalyst film is as followsThe flow of the hydrogen is 200SCCM in the heating process, the flow of the argon is 100SCCM, and the air pressure is kept to be 10pa in the heating process; the carbon source gas is acetylene, the air pressure is kept at 10pa in the growth process, the growth time is 60min, and the growth temperature is 700 ℃.