TWI516629B - Method and device for making carbon nanotube array - Google Patents

Description

Nano carbon tube array preparation device and preparation method

The invention relates to a preparation device and a preparation method of a carbon nanotube array.

The carbon nanotube is a new type of Venom material with excellent comprehensive mechanical properties such as high elastic modulus, high Young's modulus and low density, as well as excellent electrical properties, thermal properties and adsorption properties. The carbon nanotubes may exhibit metallic or semiconducting properties as the carbon nanotube arrangement of the carbon nanotubes changes. Due to the excellent properties of the carbon nanotubes, it is expected to play an important role in the fields of nanoelectronics, materials science, biology, and chemistry, and the carbon nanotube arrays are neatly arranged due to the arrangement of the carbon nanotubes. To make it more conducive to industrial applications. The method of forming a carbon nanotube array is mainly a chemical vapor deposition (CVD) method. The chemical vapor deposition method mainly uses a nanometer-scale transition metal or its oxide as a catalyst to pyrolyze a carbon source gas at a certain temperature to prepare a carbon nanotube array. At present, the chemical vapor deposition method generally adopts a planar growth substrate, and the planar growth substrate is not limited by the size of the reaction chamber, so that the area of the carbon nanotube array grown thereon is increased. It can't be done very much.

A method for growing a large area of carbon nanotube film is disclosed in the specification of Taiwan Patent Application No. 200801224, published on Jan. 1, 2008. The method is specifically for providing a cylindrical substrate, and depositing a catalyst layer on the outer surface of the substrate; placing the substrate on which the catalyst layer is deposited in a reaction chamber; and introducing a shielding gas into the reaction chamber to make the reaction chamber Maintaining a predetermined gas pressure; heating the reaction chamber to a predetermined temperature; introducing a carbon source gas into the reaction chamber, and obtaining a layer of carbon nanotube film on the substrate after a predetermined time. The patent application adopts a cylindrical substrate as a carrier for the growth of the carbon nanotube film, so that a reaction chamber with a certain capacity can accommodate a larger area of the substrate, thereby realizing large-area growth of the carbon nanotube film in a small reaction chamber.

However, the above preparation method heats the substrate by heating the reaction chamber. When the carbon nanotube is grown on the surface of the cylindrical substrate, after the surface of the substrate forms a carbon nanotube film, heat is transferred to the carbon nanotube film through the carbon nanotube film. The surface of the substrate, because the carbon nanotubes will absorb a part of the heat, makes the time for heating the catalyst on the substrate longer, so that the speed of pyrolysis of the carbon source gas is slowed down, and finally the speed of growing the carbon nanotubes is slowed down. This phenomenon will become more apparent as the height of the carbon nanotubes grows.

In view of the above, it is necessary to provide a method and a device for preparing a carbon nanotube array in which the heating speed of the substrate is faster and the growth speed of the carbon nanotubes is faster.

A method for preparing a carbon nanotube array, comprising the steps of: providing a cylindrical substrate having a smooth outer surface, the outer surface is deposited with a catalyst layer; providing a reaction chamber for depositing a catalyst a cylindrical base of the layer is disposed in the reaction chamber; a heating device is provided, the heating device is disposed inside the cylindrical substrate, and the air in the reaction chamber is discharged, and then the heating device is used to heat the cylindrical substrate To a predetermined temperature; a carbon source gas is introduced into the reaction chamber to grow on the cylindrical substrate to obtain an array of carbon nanotubes.

A method for preparing a carbon nanotube array, comprising the steps of: providing a cylindrical substrate having a catalyst layer on an outer surface, disposing it in a reaction chamber through which a protective gas is passed; providing a heating device and placing the same in the cylindrical shape Inside the substrate, and discharging the air in the reaction chamber, after which the heating device is used to heat the cylindrical substrate to a predetermined temperature; and a predetermined partial pressure carbon source gas is introduced into the reaction chamber, thereby forming the cylindrical substrate An outer carbon nanotube array is grown on the outer surface.

A preparation device for a carbon nanotube array, comprising: a reaction chamber comprising an air inlet and an air outlet; a cylindrical base disposed in the reaction chamber; wherein the carbon nanotube array The preparation device further includes a heating device disposed inside the cylindrical substrate.

Compared with the prior art, the present invention directly places the heating device inside the through hole of the cylindrical substrate, so that the heating device and the grown carbon nanotube array are respectively placed on both sides of the cylindrical substrate. Therefore, the heat conducted by the heating device is not easily absorbed by the grown carbon nanotubes or other medium and can be sufficiently absorbed by the substrate. Therefore, the method can accelerate the heating rate of the substrate and further accelerate the growth rate of the carbon nanotubes.

The preparation method and preparation apparatus of the carbon nanotube array provided by the embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

Referring to FIG. 1 , FIG. 2 and FIG. 3 , an embodiment of the present invention provides a method for preparing a carbon nanotube array, which includes the following steps:

Step 1: A cylindrical substrate 10 is provided, the cylindrical substrate 10 having an outer surface 12.

The cylindrical substrate 10 is a hollow cylinder structure, and the cylindrical substrate 10 has a through hole 16 which may have a circular, elliptical, triangular, quadrangular cross section or other regular or irregular polygonal shape. And the cross section of the entire cylindrical substrate 10 may also be a circle, an ellipse, a triangle, a quadrangle, or other regular or irregular polygons. The material of the cylindrical substrate 10 is made of a material resistant to high temperatures such as quartz, ceramics, a high temperature resistant glass substrate, tantalum or a metal material. In this embodiment, the cylindrical substrate 10 and the through hole 16 have a circular cross section, and the material thereof is quartz. In order to obtain an ordered array of carbon nanotube arrays 40, the cylindrical substrate 10 is required to have a smooth outer surface 12 which can be obtained by mechanical polishing or electrochemical polishing. Further, referring to FIG. 3, the cylindrical wall of the cylindrical substrate 10 may further include an opening 18, and the specific shape and size of the opening 18 are not limited, and may be specifically selected according to actual needs, and preferably, the opening 18 The size is preferably such that the heating means in the subsequent step of the preparation method can be placed in the through hole 16 of the cylindrical substrate 10.

In step two, a catalyst layer 14 is formed on the outer surface 12 of the cylindrical substrate 10.

The material of the catalyst layer 14 may be selected from iron (Fe), cobalt (Co), nickel (Ni) or oxides of the metals, and the catalyst layer 14 may be formed by thermal deposition, electron beam deposition, evaporation or magnetron. A method such as sputtering is formed on the outer surface 12 of the cylindrical substrate 10 described above. The thickness of the catalyst layer 14 can be specifically set according to actual needs. In the present embodiment, the thickness thereof is from 1 nm to 10 nm.

This step may further include annealing the catalyst layer 14 such that the catalyst layer 14 forms nano-sized catalyst particles. If the catalyst is a metal, the metal is oxidized to a metal oxide accompanied by an oxidation reaction during the annealing. The size of the particles obtained after the annealing will determine the diameter of the carbon nanotubes to be grown later.

Step 3: A reaction chamber 20 is provided, and the cylindrical substrate 10 on which the catalyst layer 14 is formed is disposed in the reaction chamber 20.

The reaction chamber 20 includes an air inlet 22 and an air outlet 24 respectively disposed at two ends of the reaction chamber 20. In this embodiment, the reaction chamber is a quartz tube, and the air inlet 22 and the air outlet 24 are located at both ends of the quartz tube along the axial direction. The step further includes providing a support 26 and securing the cylindrical substrate 10 within the reaction chamber 20 through the support 26. Preferably, the cylindrical substrate 10 is placed along the axial direction of the reaction chamber 20, that is, the extending direction of the through hole 16 of the cylindrical substrate 10 is along the axial direction of the reaction chamber 20. This arrangement allows the reaction gas entering the reaction chamber 20 from the inlet port 22 to be blocked by the cylindrical substrate 10 to a minimum, thereby avoiding a decrease in the growth rate of the carbon nanotubes. Meanwhile, since the cylindrical substrate 10 has a cylindrical shape, the cylindrical substrate 10 can effectively utilize the space of the reaction chamber as compared with the planar substrate, so that it can accommodate a larger area of the substrate, thereby obtaining more Large area of carbon nanotube array.

Step 4: providing a heating device 30, the heating device 30 is disposed inside the cylindrical substrate 10, and the air in the reaction chamber 20 is discharged, and then the heating device is used to heat the cylindrical substrate 10 to a Scheduled temperature.

Specifically, the heating device 30 is disposed in the through hole 16 of the cylindrical substrate 10, and is specifically arranged to uniformly heat the entire cylindrical substrate 10 according to the entire cylindrical substrate 10 and the through hole 16 Specific settings for cross-sectional area. In this embodiment, since the cylindrical substrate 10 and the through hole 16 have a circular cross section, the heating device 30 is disposed at the axis of the through hole 16 of the cylindrical substrate 10, so that the entire cylinder can be The substrate 10 is heated uniformly. The heating device 30 can be loaded into the cylindrical substrate 10 through both ends of the through hole 16 of the cylindrical substrate 10, or can be loaded through the opening 18 of the cylindrical substrate 10. The heating device 30 may be a resistance wire heating tube, an infrared heating tube or a bismuth molybdenum rod heater or the like. In this embodiment, the heating device 30 can be an infrared quartz heating lamp tube, and both ends of the infrared heating lamp tube can be clamped and fixed in the cylindrical substrate 10 through a bracket 28. Specifically, the heating device 30 can be inserted into the through hole 16 through the opening 18, and both ends of the heating device 30 can be fixed by the bracket 28. In addition, the heating device 30 can also be inserted into the through hole 16 through one end of the through hole 16, and one end of the heating device 30 is fixed by the bracket 28.

After the heating device 30 is disposed in the cylindrical substrate 10, the air in the reaction chamber 20 needs to be discharged to prevent the carbon source gas in the subsequent step from reacting with the air, and then the heating device 30 is used to heat the cylindrical device. Substrate 10 to a predetermined temperature.

The manner of discharging the air may include the following three types: directly evacuating the reaction chamber; introducing a shielding gas into the reaction chamber, and discharging the air in the reaction chamber through the shielding gas; in addition, the method may also vacuum the reaction chamber 20 and then pass through The gas is shielded and maintained at a predetermined gas pressure in the reaction chamber 20. The third mode is selected in this embodiment.

The specific manner of introducing the shielding gas is: introducing a shielding gas into the reaction chamber 20 from the air inlet 22, and the shielding gas may be argon gas or nitrogen gas or other carbon source gas that does not subsequently pass through. Gas. The input of the shielding gas allows air in the reaction chamber 20 to be discharged through the gas outlet 24. Preferably, this step vacuums the reaction chamber 20 prior to passing the shielding gas. In the environment of the shielding gas, the catalyst layer 14 on the surface of the cylindrical substrate 10 is heated to a growth temperature of the carbon nanotubes by the above-described heating device 30, that is, 500 ° C to 800 ° C.

Step 5: A carbon source gas is introduced into the reaction chamber 20 to grow the carbon nanotube array 40.

The carbon source gas is ethylene, methane, ethane, acetylene or other gaseous hydrocarbons. In this embodiment, the carbon source gas is ethylene. The reaction time is from 10 minutes to 2 hours, so that an outer surface 12 of the cylindrical substrate 10 is grown to obtain an array of carbon nanotubes 40.

Specifically, the carbon source gas and the shielding gas are introduced into the reaction chamber 20 from the inlet port 22 at a predetermined volume ratio and at a fixed flow rate, and simultaneously the reaction gas is outputted from the gas outlet port 24 at the same flow rate. The chamber 20 is configured to keep the carbon source gas flowing in the reaction chamber 20, and the carbon source gas participating in the reaction in the reaction chamber 20 is updated in time to maintain the concentration substantially unchanged, thereby obtaining high quality nanometer. Carbon tube array 40. The volume ratio of the shielding gas to the carbon source gas is preferably 1:0 to 1:10, and the flow rate of the shielding gas and the flow rate of the carbon source gas depend on the specific size of the cavity of the reaction chamber 20, if the chamber of the reaction chamber 20 When the body diameter is 4 inches to 6 inches, the flow rate of the shielding gas may be 200 sccm (Standard Cubic Centimeters Minute) ~ 500 sccm, and the flow rate of the carbon source gas may be 20 sccm to 60 sccm. In this embodiment, the chamber of the reaction chamber 20 has a diameter of 4 inches, the flow rate of the shielding gas is 360 sccm, and the flow rate of the carbon source gas is 40 sccm.

Further, in the method for preparing the carbon nanotube array 40 in the embodiment, the reaction chamber 20 may be directly constituted by a cavity of a heating furnace (not shown), and the heating furnace may be further heated simultaneously with the heating device 30. The reaction chamber 20 is such that the reaction chamber 20 reaches the reaction temperature of the growth carbon nanotube array 40 faster.

Referring to FIG. 2 and FIG. 3, specifically, the preparation device used in the method for preparing the carbon nanotube array 40 includes: a reaction chamber 20, the reaction chamber 20 includes an air inlet 22 and an air outlet 24; A cylindrical substrate 10 disposed in the reaction chamber 20; and a heating device 30 disposed inside the cylindrical substrate 10. In addition, the preparation device further includes a support body 26 for supporting the cylindrical substrate 10, and an opening 18 may be further disposed on the wall of the cylindrical substrate 10. The specific structure of the preparation apparatus has been described in detail in the preparation method of the above embodiment, and will not be described herein.

In the preparation method and the preparation device of the above embodiment, since the heating device is disposed inside the cylindrical substrate, the protective gas and the carbon source gas are removed between the heating device and the cylindrical substrate. No other medium absorbs the heat generated by the heating device, so that the growth of the substrate is faster, so that the carbon nanotubes can have a faster growth rate. In addition, the method can uniformly heat the substrate, and the heating speed and the heating temperature of the substrate can be directly controlled by controlling the heating device, so that the temperature of the substrate can be controlled, thereby better controlling the carbon nanotubes. speed of growth.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by persons skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

10‧‧‧Cylinder base

12‧‧‧ outer surface

14‧‧‧ catalyst layer

16‧‧‧through hole

18‧‧‧ openings

20‧‧‧Reaction room

22‧‧‧air inlet

24‧‧‧ outlet

26‧‧‧Support

28‧‧‧ bracket

30‧‧‧ heating device

40‧‧‧Nano Carbon Tube Array

1 is a flow chart of a method for preparing a carbon nanotube array provided by an embodiment of the present invention.

2 is a schematic view of a preparation apparatus of a carbon nanotube array provided by an embodiment of the present invention.

3 is a cross-sectional view of a cylindrical base having an opening according to an embodiment of the present invention.

10‧‧‧Cylinder base

12‧‧‧ outer surface

14‧‧‧ catalyst layer

16‧‧‧through hole

20‧‧‧Reaction room

22‧‧‧air inlet

24‧‧‧ outlet

26‧‧‧Support

28‧‧‧ bracket

30‧‧‧ heating device

40‧‧‧Nano Carbon Tube Array

Claims (18)

A method for preparing a carbon nanotube array, comprising the steps of:
Providing a cylindrical substrate having a smooth outer surface, the outer surface being deposited with a catalyst layer;
Providing a reaction chamber, the cylindrical substrate on which the catalyst layer is deposited is disposed in the reaction chamber;
Providing a heating device, the heating device is disposed inside the cylindrical substrate, and the air in the reaction chamber is discharged, and then the heating device is used to heat the cylindrical substrate to a predetermined temperature;
A carbon source gas is introduced into the reaction chamber to grow on the cylindrical substrate to obtain an array of carbon nanotubes. The method for preparing a carbon nanotube array according to claim 1, wherein before the step of introducing a carbon source gas into the reaction chamber, a shielding gas is introduced into the reaction chamber to keep the reaction chamber for a predetermined period. Air pressure. The method for preparing a carbon nanotube array according to claim 1, wherein the carbon source gas is always maintained during the entire growth of the carbon nanotube array. The method for preparing a carbon nanotube array according to claim 1, wherein the predetermined temperature is 500 ° C to 800 ° C. The method for preparing a carbon nanotube array according to claim 1, wherein the cylindrical substrate has a through hole disposed along an axial direction of the cylindrical base, and the extending direction of the through hole is along the reaction chamber. The direction of the axis. The method for preparing a carbon nanotube array according to claim 5, wherein the through hole has a circular, elliptical, triangular, quadrangular or polygonal cross section. The method for preparing a carbon nanotube array according to claim 5, wherein the heating device is disposed in a through hole in the interior of the cylindrical substrate at an axis of the cylindrical substrate. The method for preparing a carbon nanotube array according to claim 1, wherein the cylindrical substrate has a circular, elliptical, triangular, quadrangular or polygonal cross section. The method for preparing a carbon nanotube array according to claim 1, wherein the heating device is a resistance wire heating tube, an infrared heating tube or a bismuth molybdenum rod heater. A method for preparing a carbon nanotube array, comprising the steps of:
Providing a cylindrical substrate having a catalyst layer on the outer surface, the cylindrical substrate being disposed in a reaction chamber through which a shielding gas is passed;
Providing a heating device, disposing the heating device inside the cylindrical substrate, and discharging air in the reaction chamber, and then heating the cylindrical substrate to a predetermined temperature by using the heating device; and introducing a reaction chamber into the reaction chamber A carbon source gas is divided in a predetermined pressure to grow an array of carbon nanotubes on the outer surface of the cylindrical substrate. A preparation device for a carbon nanotube array, comprising:
a reaction chamber comprising an air inlet and an air outlet;
a cylindrical substrate disposed in the reaction chamber; wherein
The preparation device of the carbon nanotube array further includes a heating device disposed inside the cylindrical substrate. The apparatus for preparing a carbon nanotube array according to claim 11, wherein the cylindrical base further comprises an opening provided in the wall of the cylindrical base. The apparatus for preparing a carbon nanotube array according to claim 12, wherein the heating device is fixed in the reaction chamber by a bracket. The apparatus for preparing a carbon nanotube array according to claim 13, wherein the heating device is disposed inside the cylindrical base through the opening, and both ends of the heating device are fixed to the same by the bracket Said reaction chamber. The apparatus for preparing a carbon nanotube array according to claim 13, wherein the cylindrical base has a through hole disposed along an axial direction of the cylindrical base, and the extending direction of the through hole is along the reaction chamber The direction of the axis. The apparatus for producing a carbon nanotube array according to claim 15, wherein the heating device is inserted into the inside of the through hole from one end of the through hole of the cylindrical substrate, and one end of the heating device passes The stent is fixed in the reaction chamber. The apparatus for preparing a carbon nanotube array according to claim 11, wherein the heating device is an infrared heating lamp. The apparatus for preparing a carbon nanotube array according to claim 11, further comprising a support for supporting the cylindrical base.