TWI417412B - A carbon nanotube array and method for making the same - Google Patents

Description

Nano carbon tube array and preparation method thereof

The invention relates to a carbon nanotube array and a preparation method thereof, in particular to an isotope-doped carbon nanotube array and a preparation method thereof.

The isotope labeling method is a powerful tool for studying the growth mechanism of materials. Therefore, the isotope-labeled nanomaterial can study the growth mechanism of the nanomaterial. The isotope-labeled nanomaterial will be used in the synthesis of nanomaterials. A reactant of an isotope of a specific element (generally a light element such as carbon, boron, nitrogen or oxygen) is allowed to participate in a reaction at a predetermined concentration (in the form of a pure substance or a mixture), thereby preparing the in situ growth. Isotopically labeled nanomaterials.

The patent entitled "Isotope-doped carbon nanotube and method and apparatus for forming the same" is disclosed in the patent No. 7,029,751 B2, issued on Apr. 18, 2006, the disclosure of which is incorporated herein by reference. Array and its preparation method. The isotope-doped carbon nanotube array comprises a first carbon nanotube segment and a second carbon nanotube segment composed of a single isotope, the first carbon nanotube segment and the second carbon nanotube segment along the Nai The longitudinal direction of the carbon nanotubes is alternately arranged. The method for preparing an isotope-doped carbon nanotube array comprises the steps of: providing an ethylene gas composed of ¹² C and ¹³ C, respectively; providing a substrate on which a catalyst layer is formed, and placing the substrate in a reaction chamber; The reaction chamber is evacuated, and a protective gas of a predetermined pressure is introduced; under the reaction condition of 650 ° C to 750 ° C, the ethylene gas composed of ¹² C is reacted to generate a first carbon nanotube segment; after time, the carbon source gas is switched to the ethylene composition by ¹³ C, under the reaction conditions of 650 ℃ ~ 750 ℃, ethylene gas is composed of from ¹³ C to react, a second carbon nanotube segments continue to grow, so that An array of carbon nanotubes doped with isotopes is obtained.

In the prior art, the carbon nanotube array is composed of a single carbon nanotube doped with the same isotope. However, the prior art does not disclose a carbon nanotube array having a plurality of arrays of nanotubes doped with different isotopes.

In view of the above, it is necessary to provide a carbon nanotube array having a plurality of nano carbon tube arrays doped with different isotopes and a preparation method thereof.

A method for preparing a carbon nanotube array, comprising: providing a substrate formed with a catalyst layer, and placing the substrate formed with the catalyst layer into a reaction chamber; providing at least two carbon source gases, the at least two carbons The carbon elements in the source gas are respectively composed of different kinds of single carbon isotopes; and the at least two carbon source gases are simultaneously introduced into the reaction chamber, and the temperature of the catalyst layer is controlled to achieve different regions of the catalyst layer respectively. Different reaction temperatures, and the at least two carbon source gases react in different regions of the catalyst layer to form carbon nanotubes containing different kinds of carbon isotopes to form a carbon nanotube array.

A carbon nanotube array prepared by the method for preparing the carbon nanotube array, wherein the carbon nanotube array is composed of an array of at least two nano carbon tubes, the at least two nano carbon tube arrays They are composed of carbon nanotubes containing different combinations of carbon isotopes.

Compared with the prior art, the carbon nanotube array is a carbon nanotube array having a plurality of carbon nanotube arrays, and the carbon nanotubes in the plurality of nano carbon tube arrays are respectively doped with different isotopes .

The preparation method of the carbon nanotube array can obtain a plurality of dopings by controlling the temperature of the catalyst layer to achieve different reaction temperatures in different regions of the catalyst layer, and reacting various carbon source gases in different regions of the catalyst layer. An array of nano carbon tubes with different isotopes. Therefore, the preparation method can prepare a plurality of carbon nanotubes doped with different isotopes at one time, which reduces the preparation time. Moreover, the method can conveniently obtain an isotope-doped nano carbon tube array having various patterns by controlling the temperature of different regions of the catalyst layer.

10;20;30;40‧‧・nano carbon nanotube array

12;14;22;24;26‧‧‧Nano carbon nanotube fragments

32;34;36;42;44;46‧‧・Nano carbon pipe array

100;200‧‧‧Reaction device

102; 202‧‧‧Protective gas input channel

104;106;108;204;206;208‧‧‧carbon source input channel

110; 210‧‧‧ exhaust passage

112;114;116;118;212;214;216;218‧‧‧ valves

120; 220‧‧‧Reaction room

122; 222‧‧‧Reaction furnace

130; 230‧‧‧ catalyst layer

132; 232‧‧‧ base

140; 240‧‧ ‧ laser heating device

1 is a flow chart showing a method of preparing a carbon nanotube array according to a first embodiment of the present invention.

Fig. 2 is a schematic view showing a preparation apparatus of a carbon nanotube array according to a first embodiment of the present invention.

Figure 3 is a schematic illustration of a carbon nanotube array prepared in accordance with a first embodiment of the present invention.

Figure 4 is a schematic illustration of a carbon nanotube array prepared in accordance with a second embodiment of the present invention.

Figure 5 is a schematic view showing a preparation apparatus of a carbon nanotube array of a third embodiment of the present invention.

Figure 6 is a flow chart showing a method of preparing a carbon nanotube array according to a fourth embodiment of the present invention.

Fig. 7 is a schematic view showing a preparation apparatus of a carbon nanotube array according to a fourth embodiment of the present invention.

Figure 8 is a schematic illustration of a carbon nanotube array prepared in accordance with a fourth embodiment of the present invention.

Figure 9 is a schematic view showing a preparation apparatus of a carbon nanotube array according to a fifth embodiment of the present invention.

Figure 10 is a schematic illustration of a carbon nanotube array prepared in accordance with a fifth embodiment of the present invention.

The invention will be further described in detail below with reference to the drawings and specific embodiments.

Referring to FIG. 1 , a first embodiment of the present invention provides a method for preparing a carbon nanotube array. The preparation method mainly includes the following steps: (S101) providing a substrate formed with a catalyst layer, and forming the catalyst layer. The substrate is placed in a reaction chamber; (S102) providing at least two carbon source gases, the carbon elements of the at least two carbon source gases are respectively composed of different kinds of single isotopes; and (S103) the at least two carbons The source gas is simultaneously introduced into the reaction chamber, and by controlling the reaction temperature, the at least two carbon source gases are reacted at different temperatures to form an array of carbon nanotubes.

In step S101, a substrate formed with a catalyst layer is provided, and the substrate on which the catalyst layer is formed is placed in a reaction chamber.

Referring to Figure 2, a substrate 132 is provided having a flat, smooth surface. The substrate 132 may be a polished ruthenium, a polished ruthenium dioxide sheet or a polished quartz sheet. The surface flatness of the substrate 132 is preferably less than 10 nm. In this embodiment, a polished cymbal is selected as the substrate 132.

A catalyst layer 130 is formed on the surface of the substrate 132. The catalyst layer 130 may be deposited on the surface of the substrate 132 by an electron beam evaporation method, a deposition method, a sputtering method, or an evaporation method. The thickness of the catalyst layer 130 is generally from 3 nm to 6 nm. The catalyst layer 130 forms a good chemical or physical bond with the substrate 132. The material of the catalyst layer 130 may be selected from iron, cobalt, nickel, and alloy materials of any combination thereof. In the present embodiment, an iron film having a thickness of 5 nm is selected as the catalyst layer 130. The iron film can form good contact with the polished ruthenium.

Providing a reaction device 100, the reaction device 100 includes: a reaction chamber 120, a The reaction furnace 122 for heating the reaction chamber 120, a shielding gas input passage 102, three carbon source gas input passages 104, 106, 108, and an exhaust passage 110 are provided. The reaction chamber 120 is configured to carry the substrate 132 formed with the catalyst layer 130; the reaction furnace 122 includes a heating device that heats the reaction chamber 120 and causes the reaction chamber 120 to reach one Scheduled temperature. The shielding gas input channel 102 is provided with a valve 112 through which different inert gases, such as helium, argon, nitrogen, etc., can be input; the carbon source gas input channel 104 is provided with a valve 114. The carbon source gas input passage 106 is provided with a valve 116. The carbon source gas input passage 108 is provided with a valve 118, and the carbon source gas input passages 104, 106, 108 can respectively input different carbon source gases.

The substrate 132 on which the catalyst layer 130 is formed is placed in the reaction chamber 120. The catalyst layer 130 faces the carbon source gas inlet direction and forms a certain angle α with the horizontal plane, 0°≦α<90°. It can be understood that by adjusting the angle between the catalyst layer 130 and the horizontal plane, the uniformity of growth of the carbon nanotube array can be improved. The angle can be adjusted according to actual needs. In the embodiment, the angle formed by the catalyst layer and the horizontal plane is 0°. It can be understood that by placing the substrate 132 on which the catalyst layer 130 is formed into the reaction chamber 120, the reaction chamber 120 and the catalyst layer 130 can be heated by the heating device in the reaction furnace 122. The reaction chamber 120 and the catalyst layer 130 reach a predetermined temperature.

Step S102, providing at least two carbon source gases, wherein the carbon elements in the at least two carbon source gases are respectively composed of different kinds of single isotopes.

The carbon source gas may be input to the reaction chamber 120 through the carbon source gas input passages 104, 106, and 108. The carbon source gas may be methane, ethylene, acetylene, propadiene, and other hydrocarbons. The at least two carbon source gases refer to carbon source gases of at least two different materials, such as ethylene and acetylene; or methane and ethylene, etc., and the carbon sources in the carbon source gases of the at least two different materials are different types Single isotope composition, such as ¹² C, ¹³ C, ¹⁴ C, etc. In this embodiment, two different carbon source gases are provided, which are respectively an acetylene having a ¹² C isotope and an ethylene containing a ¹³ C isotope, and the two carbon source gases can pass through the carbon source respectively. Gas input channels 104 and 106 are input to reaction chamber 120.

Step S103, simultaneously introducing the at least two carbon source gases into the reaction chamber, and controlling the reaction temperature to react the at least two carbon source gases at different temperatures to form a carbon nanotube array.

In this embodiment, first, after the reaction chamber 120 is evacuated through the exhaust passage 110, a shielding gas of a predetermined pressure is introduced through the shielding gas input passage 102. In this embodiment, the argon is at a pressure of 1 atmosphere. The valves 114 and 116 are opened, and the acetylene gas consisting of ¹² C and the ethylene gas consisting of ¹³ C are simultaneously introduced into the reaction chamber 120 through the carbon source gas input passages 104 and 106, and the flow rates of the two gases are both 120 sccm ( In the standard state, every cubic centimeter per minute, the flow rate is 1.2 cm / s; the reaction chamber 120 is heated by a heating device in the reaction furnace 122, so that the reaction chamber 120 reaches a first temperature, the first temperature A reaction temperature for preparing a carbon nanotube for catalyzing the decomposition of acetylene gas, the first temperature being about 600 ° C to 650 ° C. Since the first temperature only reaches the reaction temperature for preparing the carbon nanotube by decomposition of acetylene gas, and does not reach the reaction temperature for preparing the carbon nanotube by ethylene gas decomposition, only acetylene gas composed of ¹² C is used in the reaction. A decomposition reaction occurs, and a carbon nanotube segment composed of ¹² C is formed on the catalyst layer iron film.

Next, after the predetermined time of the reaction, the temperature of the reaction chamber 120 is controlled by the heating device in the reaction furnace 122, so that the reaction chamber 120 reaches a second temperature, the second temperature is greater than the first temperature, the second The temperature is a reaction temperature for catalyzing the decomposition of the ethylene gas to prepare a carbon nanotube, and the second temperature is about 650 ° C to 800 ° C. It can be understood that, since the second temperature is higher than the reaction temperature for preparing the carbon nanotube by the reaction of the catalytic acetylene gas, and since the growth point of the carbon nanotube is on the catalyst iron film, in the course of the reaction, ¹² The acetylene gas composed of C and the ethylene gas composed of ¹³ C are simultaneously decomposed, and carbon atoms generated by the decomposition reaction are deposited on the iron film of the catalyst layer, and a carbon nanotube segment composed of ¹³ C and ¹² C is generated, which A carbon nanotube fragment lifts the carbon nanotube segment consisting of ¹² C, that is, a carbon nanotube segment composed of ¹³ C and ¹² C is grown on the ¹² C carbon nanotube segment The bottom end.

Finally, after the reaction is continued for a predetermined period of time, the reaction chamber 120 is cooled to room temperature, and an array of carbon nanotubes is obtained on the iron film of the catalyst layer.

In addition, the above steps can be repeated to prepare an array of carbon nanotubes that are periodically arranged alternately.

Referring to FIG. 3, a carbon nanotube array 10 prepared according to a first embodiment of the present invention, the carbon nanotube array 10 includes a plurality of carbon nanotubes, the plurality of carbon nanotubes being composed of a first nanocarbon a tube segment 12 and a second carbon nanotube segment 14; the second carbon nanotube segment 14 is formed on the catalyst layer iron film, and the first carbon nanotube segment 12 is formed on the second nanometer On the carbon tube segment 14; wherein the first carbon nanotube segment 12 is composed of ₁₂ C, and the second carbon nanotube segment 14 is composed of ¹² C and ¹³ C.

The carbon nanotubes can be single-walled carbon nanotubes, double-walled carbon nanotubes, and multi-walled carbon nanotubes. In this embodiment, the carbon nanotube is a multi-walled carbon nanotube.

The carbon nanotubes have a diameter of 0.5 to 50 nm and a length of 50 nm to 5 mm. The first carbon nanotube segment 12 and the second carbon nanotube segment 14 have equal or unequal lengths Degree can be prepared according to actual needs. In this embodiment, the length of the carbon nanotubes is preferably from 100 micrometers to 900 micrometers, and the first carbon nanotube segments 12 and the second carbon nanotube segments 14 have substantially equal lengths.

It can be understood that, in step S103, the reaction chamber 120 can be heated first by the heating device in the reaction furnace 122, so that the first temperature of the reaction chamber 120 reaches a reaction temperature for catalyzing the decomposition of ethylene gas to prepare a carbon nanotube, that is, The first temperature of the reaction chamber 120 is brought to between 650 ° C and 800 ° C. At this time, since the first temperature is higher than the reaction temperature for preparing the carbon nanotube by decomposition of the acetylene gas, the acetylene gas composed of ¹² C and the ethylene gas composed of ¹³ C are simultaneously decomposed during the reaction, and the generated A carbon nanotube segment composed of ¹³ C and ¹² C is deposited on the iron film of the catalyst layer; secondly, after a predetermined time of reaction, the temperature of the reaction chamber 120 is controlled by a heating device in the reaction furnace 122 to make the reaction chamber The second temperature of 120 is only up to the reaction temperature at which the acetylene gas is decomposed to produce a carbon nanotube, that is, the temperature of the reaction chamber 120 is lowered to 600 ° C - 650 ° C. At this time, since the second temperature only reaches the reaction temperature for catalyzing the decomposition of the acetylene gas to prepare the carbon nanotubes, only the acetylene gas composed of ¹² C is decomposed during the reaction, and the generated ¹² C is formed. A carbon nanotube segment is deposited on the catalyst layer iron film, and the carbon nanotube segment composed of ¹³ C and ¹² C is lifted up, that is, the generated carbon nanotube segment composed of ¹² C is grown in the The bottom end of the carbon nanotube segment consisting of ¹³ C and ¹² C is described.

A second embodiment of the present invention provides a method for preparing a carbon nanotube array. The preparation method mainly comprises the following steps: (S201) providing a substrate formed with a catalyst layer, and placing the substrate formed with the catalyst layer into a reaction (S202) providing at least two carbon source gases, the carbon elements of the at least two carbon source gases being respectively composed of different kinds of single isotopes; and (S203) simultaneously introducing the at least two carbon source gases In the reaction chamber, by controlling the reaction temperature, the at least two carbon source gases are reacted at different temperatures to form an array of carbon nanotubes.

The step S201 and the step S202 are substantially the same as the step S101 and the step S102 in the first embodiment of the present invention, except that a third carbon source gas is further provided, wherein the carbon in the third carbon source gas The element is also composed of a single isotope, and the isotopes constituting the carbon in the third carbon source gas are different from the isotopes constituting the carbon in the two carbon source gases in the first embodiment of the present invention. The third carbon source gas in this embodiment is methane containing a ¹⁴ C isotope. The methane containing the ¹⁴ C isotope is input to the reaction chamber 120 from the carbon source gas input passage 108.

The step S203 is substantially the same as the step S103 in the first embodiment of the present invention, except that a carbon nanotube segment composed of ¹² C and ¹³ C is grown on the carbon nanotube segment composed of ¹² C. After the bottom end, the method further comprises: controlling the temperature of the reaction chamber 120 by a heating device in the reaction furnace 122 to bring the reaction chamber 120 to a third temperature. The third temperature is a reaction temperature for catalyzing the decomposition of methane gas to prepare a carbon nanotube, and the third temperature is about 850 ° C to 1100 ° C. Since the third temperature simultaneously reaches the reaction temperature for preparing the carbon nanotubes by decomposition of acetylene, ethylene and methane gas, acetylene gas consisting of ¹² C, ethylene gas consisting of ¹³ C and ¹⁴ C are used in the reaction. The methane gas of the composition is simultaneously decomposed, and a carbon nanotube segment composed of ¹² C, ¹³ C and ¹⁴ C is deposited on the iron film of the catalyst layer, and a carbon nanotube segment composed of ¹² C and ¹³ C is formed. Jacking up, i.e., the carbon nanotube segments are grown at the bottom end of the carbon nanotube segments consisting of ¹² C and ₁₃ C.

Finally, after the reaction is continued for a predetermined period of time, the reaction chamber 120 is cooled to room temperature, and an array of carbon nanotubes is obtained on the iron film of the catalyst layer.

In addition, the above steps can be repeated to prepare a carbon nanotube array which is periodically arranged alternately. In addition, the reaction chambers 120 can be successively brought to different reaction temperatures by heating means in the reaction furnace 122, and finally different types of carbon nanotube arrays are prepared.

Referring to FIG. 4, a carbon nanotube array 20 prepared by the second embodiment of the present invention, the carbon nanotube array 20 includes a plurality of carbon nanotubes, the plurality of carbon nanotubes being composed of a first nanocarbon a tube segment 22, a second carbon nanotube segment 24 and a third carbon nanotube segment 26; wherein the first carbon nanotube segment 22 is composed of ¹² C, the second carbon nanotube Fragment 24 consists of ¹² C and ¹³ C, and said third carbon nanotube section 26 consists of ¹² C, ¹³ C and ¹⁴ C. The first carbon nanotube section 22, the second carbon nanotube section 24, and the third carbon nanotube section 26 have equal or unequal lengths and can be obtained by controlling the reaction time according to actual needs. In this embodiment, the length of the carbon nanotubes is preferably from 100 micrometers to 900 micrometers, and the first carbon nanotube segments 22, the second carbon nanotube segments 24, and the third carbon nanotube segments 26 have Roughly equal length.

It can be understood that, in the carbon nanotube, the order of arranging the first carbon nanotube segment 22, the second carbon nanotube segment 24 and the third carbon nanotube segment 26 can be arbitrarily combined, and can be adopted during the reaction. Different carbon nanotube fragments are grown in different orders by controlling the temperature.

For example, in step 203, the temperature of the reaction chamber 120 may be first controlled by a heating device in the reaction furnace 122, so that the first temperature of the reaction chamber 120 reaches a reaction temperature for catalyzing the decomposition of methane gas to prepare a carbon nanotube. Since the first temperature is higher than the reaction temperature for preparing the carbon nanotubes by catalyzing the decomposition of acetylene and ethylene gas, the acetylene, ethylene and methane gases are simultaneously decomposed during the reaction to form ¹² C, ¹³ C and ¹⁴ C. A composition of carbon nanotube fragments is deposited on the catalyst layer iron film. Next, after the predetermined time of the reaction, the temperature of the reaction chamber 120 is controlled by the heating means in the reaction furnace 122 so that the second temperature of the reaction chamber 120 reaches only the reaction temperature for catalyzing the decomposition of ethylene gas to prepare the carbon nanotubes. At this time, since the second temperature is lower than the reaction temperature for preparing the carbon nanotube by the decomposition of the catalytic methane gas, but higher than the reaction temperature for preparing the carbon nanotube by the decomposition of the acetylene gas, only the acetylene and the reaction are carried out during the reaction. The ethylene gas undergoes a decomposition reaction, and a carbon nanotube segment composed of ¹² C and ¹³ C is formed to continue to grow at the bottom end of the carbon nanotube segment consisting of ¹² C, ¹³ C and ¹⁴ C; again, the reaction is scheduled After the time, the temperature of the reaction chamber 120 is controlled by a heating device in the reaction furnace 122 such that the third temperature of the reaction chamber 120 reaches only the reaction temperature for catalyzing the decomposition of acetylene gas to produce a carbon nanotube. At this time, since the third temperature is lower than the reaction temperature for preparing the carbon nanotube by catalytic decomposition of methane and ethylene gas, only the acetylene gas is decomposed during the reaction to form a carbon nanotube composed of ¹² C. Fragments continue to grow at the bottom end of the carbon nanotube fragments consisting of ¹² C and ¹³ C.

Referring to FIG. 5, a third embodiment of the present invention provides a method for preparing a carbon nanotube array. The preparation method mainly comprises the steps of: (S301) providing a substrate formed with a catalyst layer, and placing the substrate formed with the catalyst layer into a reaction chamber; (S302) providing at least two carbon source gases, the at least two The carbon elements in the carbon source gas are respectively composed of different kinds of single isotopes; (S303) simultaneously introducing the at least two carbon source gases into the reaction chamber, and controlling the reaction temperature by a laser heating device The at least two carbon source gases react at different temperatures to form an array of carbon nanotubes.

The step S303 is substantially the same as the step S203 in the second embodiment of the present invention, except that in the embodiment, a laser heating device 140 is used instead of the reaction furnace 122 to heat the reaction chamber 120, by controlling the reaction. The temperature of the chamber 120 is used to control the reaction temperature, or the entire catalyst layer 130 may be directly heated by the laser heating device 140, and the temperature of the catalyst layer 130 is controlled to control the reaction temperature to reach a temperature. The predetermined reaction temperature. The method for directly heating the entire catalyst layer 130 by using the laser heating device 140 is: the laser beam generated by the laser heating device 140 can be directly irradiated on the catalyst layer 130 from the front surface to heat the catalyst layer 130; The laser beam is irradiated from the back surface onto the substrate 132, that is, the surface on which the catalyst layer is not disposed, and heat is transmitted to the catalyst layer 130 through the substrate 132, thereby heating the catalyst layer 130. In this embodiment, the entire catalyst layer 130 placed in the reaction chamber 120 is heated by the laser heating device 140, so that the reaction temperature reaches a first temperature, a second temperature, and a third temperature. After the reaction for a predetermined period of time, the carbon nanotube array is obtained.

Referring to FIG. 6, a fourth embodiment of the present invention further provides a method for preparing a carbon nanotube array.

In step S401, a substrate formed with a catalyst layer is provided, and the substrate on which the catalyst layer is formed is placed in a reaction chamber.

Referring to FIG. 7, first, a substrate 232 is provided, and a catalyst layer 230 is formed on the surface of the substrate 232. The substrate 232 and the catalyst layer 230 are the same as the substrate 132 and the catalyst layer 130 of the first embodiment of the present invention.

Next, a reaction device 200 is provided. The reaction device 200 includes a reaction chamber 220, a reaction furnace 222 for heating the reaction chamber 220, a shielding gas input passage 202, three carbon source gas input passages 204, 206, 208. An exhaust passage 210 and at least one laser heating device 240. The reaction chamber 220 is configured to carry the substrate 232 formed with the catalyst layer 230; the reaction furnace 222 includes a heating device that heats the reaction chamber 220 and causes the reaction chamber 220 to reach a predetermined temperature. The shielding gas input channel 202 is provided with a valve 212 through which different inert gases such as helium, argon, or the like can be input. Nitrogen gas or the like; the carbon source gas input passage 204 is provided with a valve 214, the carbon source gas input passage 206 is provided with a valve 216, and the carbon source gas input passage 208 is provided with a valve 218 through the carbon source gas input passage. 204, 206, 208 may respectively input different carbon source gases; the at least one laser heating device 240 is configured to heat different regions of the catalyst layer 230 placed in the reaction chamber 220 to control different regions of the catalyst layer 230. A predetermined reaction temperature is reached.

Finally, the substrate 232 formed with the catalyst layer 230 is placed in the reaction chamber 220, and the catalyst layer 230 is directed toward the carbon source gas and forms a certain angle α with the horizontal plane, 0°≦α<90°. . In the present embodiment, the angle α = 45°, so that the carbon source gas forms good contact with the catalyst layer 230.

Heating the reaction chamber 220 through the reaction furnace 222 allows the catalyst layer 230 to reach a predetermined temperature. Heating the different regions of the catalyst layer 230 by the laser heating device 240 allows different regions to have different temperatures. The laser heating device 240 can directly illuminate the catalyst layer 230 to bring the catalyst layer 230 to a predetermined temperature, and can indirectly illuminate the substrate 232 from the back surface to bring the catalyst layer 230 to a predetermined temperature. In this embodiment, two laser heating devices 240 are included, and the two laser heating devices 240 directly heat a first reaction region and a second reaction region of the catalyst layer 230 to make the first reaction. The region and a second reaction zone each reach a different temperature.

In step S402, at least two carbon source gases are provided, and the carbon elements in the at least two carbon source gases are respectively composed of different kinds of carbon isotopes.

The at least two carbon source gases refer to carbon source gases of at least two different materials, such as ethylene and acetylene; or methane and ethylene, etc., and the carbon sources in the carbon source gases of the at least two different materials are different types Single isotope composition, such as ¹² C, ¹³ C, ¹⁴ C, etc. The carbon source gas may be input to the reaction chamber 220 from the carbon source gas input passages 204, 206, 208, respectively. This example includes three different carbon source gases, namely acetylene containing a ¹² C isotope, ethylene containing a ¹³ C isotope, and methane containing a ¹⁴ C isotope.

Step S403, simultaneously introducing the at least two kinds of carbon source gases into the reaction chamber, controlling the temperature of the catalyst layer so that different regions of the catalyst layer respectively reach different reaction temperatures, and the at least two carbon sources are The gas reacts in different regions of the catalyst layer to form carbon nanotubes containing different kinds of carbon isotopes, thereby forming a carbon nanotube array.

First, after the reaction chamber 220 is evacuated through the exhaust passage 210, a shielding gas of a predetermined pressure is introduced through the shielding gas input passage 202, which is an argon gas having a pressure of 1 atmosphere; and the valve is opened at the same time. 214, 216 and 218, through the carbon source gas input channels 204, 206 and 208, respectively, into the reaction chamber 220, an acetylene gas composed of ¹² C, an ethylene gas composed of ¹³ C and a methane gas composed of ¹⁴ C are simultaneously introduced. The flow rates of the three gases are both 120 sccm (standard state, per cubic centimeter per minute), and the flow rate is 1.2 cm/s; the reaction chamber 220 and the catalyst layer placed in the reaction chamber 220 are passed through a heating device in the reaction furnace 222. 230 is heated to bring the catalyst layer 230 as a whole to a first temperature, and a first reaction zone and a second reaction zone of the catalyst layer 230 are additionally heated by the two laser heating devices 240, respectively. The first reaction zone and the second reaction zone respectively reach a second temperature and a third temperature, and the second temperature and the third temperature are both greater than the first temperature. It can be understood that the first reaction region and the second reaction region may have the same or different areas and shapes, and the shapes of the first reaction region and the second reaction region may be square, circular, elliptical, rectangular, etc. Geometry; in addition, the first reaction zone and the second reaction zone may be distributed side by side, one reaction zone surrounding another reaction zone, or otherwise distributed over the surface of the catalyst layer 230. In the embodiment, the first temperature is a reaction temperature for catalyzing the decomposition of acetylene gas to prepare a carbon nanotube, and the first temperature is about 600 ° C to 650 ° C; and the second temperature is a catalytic carbon gas decomposition to prepare a carbon nanotube. Reaction temperature, the second temperature is about 650 ° C -800 ° C; the third temperature is a reaction temperature for catalyzing the decomposition of methane gas to prepare a carbon nanotube, the third temperature is about 850 ° C -1100 ° C; the first The reaction zone and the second reaction zone are distributed side by side on the surface of the catalyst layer 230, and the first reaction zone and the second reaction zone are two rectangular regions of the same area.

It can be understood that, since the temperature of the first reaction zone reaches the reaction temperature of preparing the carbon nanotube by decomposition of acetylene and ethylene gas, and the reaction temperature of preparing the carbon nanotube by methane gas decomposition is not reached, the first reaction zone is Only the acetylene gas composed of ¹² C and the ethylene gas composed of ¹³ C are decomposed, and an array of carbon nanotube tubes composed of ¹² C and ¹³ C is deposited on the catalyst layer iron film of the first reaction zone. And the temperature of the second reaction zone reaches a reaction temperature at which the acetylene, ethylene and methane gas are decomposed to prepare a carbon nanotube, so that the second reaction zone is composed of ¹² C of acetylene gas and ¹³ C of ethylene. a gas and a methane gas composed of ¹⁴ C are simultaneously decomposed, and an array of nano carbon tubes composed of ¹² C, ¹³ C, and ¹⁴ C is deposited on the catalyst layer iron film of the second reaction zone; The reaction zone of the catalyst layer 230 except the first reaction zone and the second reaction zone only reaches a reaction temperature for catalyzing the decomposition of acetylene gas to prepare a carbon nanotube, but does not reach Ethylene and methane gas decomposition reaction temperature the preparation of carbon nanotube, so only acetylene gas consisting of ¹² C decomposition reaction occurs in the reaction zone to produce a sub-array ¹² C nanotube composition deposited on the other The catalyst layer of the reaction zone is on the iron film.

Finally, after the reaction is continued for a predetermined period of time, the reaction chamber 220 is cooled to room temperature, and carbon nanotubes containing different kinds of carbon isotopes are formed on the catalyst layer iron film to form an array of carbon nanotubes.

It can be understood that, after the predetermined reaction time, the temperature of the first reaction zone, the second reaction zone, and the catalyst layer zone other than the first and second reaction zones can be controlled by the laser heating device 240, respectively. The first reaction zone, the second reaction zone, and the catalyst layer zones other than the first and second reaction zones are respectively brought to different reaction temperatures, and finally a nano carbon tube array having a plurality of carbon nanotube segments is prepared.

Referring to FIG. 8, a carbon nanotube array 30 prepared by a fourth embodiment of the present invention, the carbon nanotube array 30 comprises a first nano carbon tube array 32, a second nano carbon tube array 34 and a The third nano carbon tube array 36 is composed. The second nano carbon tube array 34 and the third nano carbon tube array have a rectangular shape; the second nano carbon tube array 34 and the third nano carbon tube array 36 have the same area; the second The nano carbon tube array 34 and the third nano carbon tube array 36 are spaced apart and surrounded by the first nano carbon tube array 32. The carbon nanotubes in the array of first carbon nanotube tubes 32 are composed of ¹² C, and the carbon nanotubes of the array of second carbon nanotube tubes 34 are composed of ¹² C and ₁₃ C, the third nanometer. The carbon nanotubes of the carbon tube array 36 are composed of ¹² C, ¹³ C and ¹⁴ C. The carbon nanotubes in the first nano carbon tube array 32, the second nano carbon tube array 34 and the third nano carbon tube array 36 have equal or unequal lengths and can be obtained according to actual needs. In this embodiment, the length of the carbon nanotubes in the carbon nanotube array 30 is preferably from 100 micrometers to 900 micrometers, and the first nano carbon tube array 32, the second nano carbon tube array 34 and the first The carbon nanotubes in the three nano carbon tube array 36 have substantially equal lengths.

It can be understood that at least two nano carbon tube arrays can be included in the carbon nanotube array 30. The carbon nanotubes in the at least two nanocarbon tube arrays may be composed of a single carbon nanotube fragment of a different kind of single carbon isotope or a combination of different kinds of carbon isotopes. The array of nano carbon tubes may have different shapes and areas, and the shape of the array of carbon nanotube tubes may be square, circular, elliptical or rectangular; other shapes of the at least two different carbon nanotube tubes The carbon nanotube array 30 can be composed of different arrangements. The different arrangement means that the at least two different carbon nanotube arrays can be arranged side by side, one sub-array surrounds the other sub-array, arranged at intervals, or otherwise formed into the carbon nanotubes. Array 30.

The carbon nanotubes can be single-walled carbon nanotubes, double-walled carbon nanotubes, and multi-walled carbon nanotubes. In this embodiment, the carbon nanotube is a multi-walled carbon nanotube, and the multi-walled carbon nanotube has a diameter of 0.5 to 50 nm.

Referring to FIG. 9, a fifth embodiment of the present invention further provides a method for preparing a carbon nanotube array. The preparation method comprises: (S501) providing a substrate formed with a catalyst layer, and placing the substrate formed with the catalyst layer into a reaction chamber; (S502) providing at least two carbon source gases, the at least two carbon sources The carbon elements in the gas are respectively composed of different kinds of carbon isotopes; (S503) simultaneously introducing the at least two carbon source gases into the reaction chamber, and controlling the temperature of the catalyst layer to achieve different regions of the catalyst layer respectively Different reaction temperatures, and the at least two carbon source gases react in different regions of the catalyst layer to form carbon nanotubes containing different kinds of carbon isotopes, thereby forming a carbon nanotube array.

The step S501 and the step S502 are substantially the same as the step S401 and the step S402 in the fourth embodiment of the present invention. The difference is that in this embodiment, three lasers are included. The thermal device 240, the three laser heating devices 240 respectively illuminate three regions of the substrate 232 from the back side of the substrate 232, and three of the catalyst layers 230 corresponding to the three regions of the substrate 232 The reaction zones reach different temperatures. By illuminating the substrate from the back side of the substrate, it is possible to prevent the laser from damaging the growth of the carbon nanotubes upon irradiation.

The step S503 is substantially the same as the step S403 in the third embodiment of the present invention. The difference is that the temperature in the reaction furnace 222 is kept at room temperature, and a first region, a second region and a third region of the substrate 232 are respectively irradiated by the three laser heating devices 240. a first reaction region, a second reaction region, and a third reaction region of the catalyst layer 230 corresponding to the first region, the second region, and the third region of the substrate 232 respectively reach a first temperature a second temperature and a third temperature. In the embodiment, the first temperature is a reaction temperature for catalyzing the decomposition of acetylene gas to prepare a carbon nanotube, and the first temperature is about 600 ° C to 650 ° C; and the second temperature is a catalytic carbon gas decomposition to prepare a carbon nanotube. The reaction temperature is about 650 ° C - 800 ° C; the third temperature is a reaction temperature for catalyzing the decomposition of methane gas to prepare a carbon nanotube, and the third temperature is about 850 ° C - 1100 ° C.

It can be understood that, since the temperature of the first reaction zone only reaches the reaction temperature of preparing the carbon nanotube by decomposition of acetylene gas, and the reaction temperature of preparing the carbon nanotube by decomposition of ethylene and methane gas is not reached, the first reaction zone is Only the acetylene gas composed of ¹² C is decomposed, and a nano carbon tube array composed of ¹² C is deposited on the catalyst layer iron film of the first reaction region; and the second reaction region The temperature only reaches the reaction temperature of the acetylene and ethylene gas to prepare the carbon nanotubes, but does not reach the reaction temperature of the methane gas decomposition to prepare the carbon nanotubes. Therefore, the acetylene gas consisting of ¹² C in the second reaction zone is composed of ¹³ The ethylene gas composed of C is simultaneously decomposed, and an array of nano carbon tubes composed of ¹² C and ¹³ C is deposited on the catalyst layer iron film of the second reaction zone; due to the reaction temperature of the third reaction zone while achieving catalytic acetylene, ethylene, and methane gas decomposition reaction temperature the preparation of carbon nanotube, so, the acetylene gas from the reaction zone consisting of ¹² C, ¹³ C composed of Alkenyl concurrent gas and methane gas consisting ^{of 14} C-decomposition reaction to produce carbon nanotubes by a sub-array ¹² C, ¹³ C and ¹⁴ C consisting of an iron catalyst layer deposited on the film of the third reaction zone. In addition, since the reaction layer of the catalyst layer 230 except the first reaction zone, the second reaction zone, and the third reaction zone does not reach a reaction temperature for catalyzing the decomposition of acetylene, ethylene, and methane gas to prepare a carbon nanotube, No gas reacts in this region and no carbon nanotubes are deposited on the catalyst layer iron film in the region.

Finally, after the reaction is continued for a predetermined period of time, the reaction chamber 220 is cooled to room temperature, and carbon nanotubes containing different kinds of carbon isotopes are formed on the catalyst layer iron film to form an array of carbon nanotubes.

It can be understood that after the predetermined reaction time, the temperature of the first reaction zone, the second reaction zone and the third reaction zone can be controlled by the laser heating device 240 to make the first reaction zone and the second reaction. The region and the third reaction zone respectively reach different reaction temperatures, and finally a nano carbon tube array having a plurality of carbon nanotube segments is prepared. Wherein, the carbon nanotubes in each nano carbon tube array are composed of a plurality of carbon nanotube segments respectively containing different kinds of single carbon isotopes or different combinations of different kinds of carbon isotopes.

For example, after step S503, the temperature of the first reaction zone, the second reaction zone, and the third reaction zone are respectively controlled by the laser heating device 240, so that the temperature of the first reaction zone reaches 650 ° C - 800 ° C, that is, the reaction temperature for catalyzing the decomposition of acetylene and ethylene gas to prepare a carbon nanotube; the temperature of the second reaction zone is 850 ° C -1100 ° C, that is, catalyzing the decomposition of methane, acetylene and ethylene gas to prepare nano carbon The reaction temperature of the tube; the temperature of the third reaction zone is from 600 ° C to 650 ° C, that is, only the reaction temperature for catalyzing the decomposition of acetylene gas to prepare the carbon nanotubes is reached. It can be understood that, since the temperature of the first reaction zone reaches a reaction temperature for catalyzing the decomposition of acetylene and ethylene gas to prepare a carbon nanotube, the reaction temperature for catalyzing the decomposition of methane gas to prepare a carbon nanotube is not reached, and the reaction process is carried out by ¹² The acetylene gas composed of C and the ethylene gas composed of ¹³ C are simultaneously decomposed to form a carbon nanotube segment composed of ¹² C and ¹³ C grown at the bottom end of the ¹² C carbon nanotube segment. Since the temperature of the second reaction zone reaches a reaction temperature for catalyzing the decomposition of methane, acetylene and ethylene gas to prepare a carbon nanotube, the reaction process comprises an acetylene gas consisting of ¹² C, an ethylene gas consisting of ¹³ C, and ¹⁴ The methane gas composed of C is simultaneously decomposed, and a carbon nanotube segment composed of ¹² C, ¹³ C and ¹⁴ C is formed and grown at the bottom end of the carbon nanotube segment consisting of ¹² C and ₁₃ C. In addition, since the temperature of the third reaction zone only reaches the reaction temperature for preparing the carbon nanotubes by catalyzing the decomposition of acetylene gas, only the acetylene gas composed of ¹² C is decomposed and reacts to form ¹² C. A carbon nanotube fragment is grown at the bottom end of the carbon nanotube fragment consisting of ¹² C, ¹³ C and ¹⁴ C.

It can be understood that the arrangement order of the carbon nanotube segments in the nano carbon tube array can also be arbitrarily combined, and different carbon nanotube fragments can be grown in different orders by controlling the temperature during the reaction.

Referring to FIG. 10, a carbon nanotube array 40 prepared by a fifth embodiment of the present invention, the carbon nanotube array 40 comprises a first nano carbon tube array 42, a second nano carbon tube array 44 and a The third nanocarbon tube array 46 is composed; each nano carbon tube array is composed of a single carbon nanotube segment containing a single type of carbon isotope or containing a combination of different types of carbon isotopes. Wherein, the carbon nanotubes in the array of first carbon nanotube tubes 42 are composed of ¹² C, and the carbon nanotubes of the array of second carbon nanotube tubes 44 are composed of ¹² C and ¹³ C, the third The carbon nanotubes of the nano carbon tube array 46 are composed of ¹² C, ¹³ C and ₁₄ C. The carbon nanotubes in the first nano carbon tube array 42, the second nano carbon tube array 44 and the third nano carbon tube array 46 have equal or unequal lengths and can be obtained according to actual needs. In this embodiment, the length of the carbon nanotubes in the carbon nanotube array 40 is preferably from 100 micrometers to 900 micrometers, and the first nano carbon tube array 42, the second nano carbon tube array 44, and the first The carbon nanotubes in the three nano carbon tube array 46 have substantially equal lengths.

The carbon nanotube array provided by the embodiment of the present invention is a carbon nanotube array having a plurality of nano carbon tube arrays, wherein the carbon nanotubes in the plurality of nano carbon tube arrays are respectively doped with different carbon nanotubes. Isotope, so it can be conveniently used to mark a plurality of samples.

The method for preparing a carbon nanotube array according to an embodiment of the present invention provides different reaction temperatures by providing various carbon source gases containing a single isotope and preparing carbon nanotubes according to decomposition of the different carbon source gases, by controlling different reactions. The temperature allows the different carbon source gases to decompose and grow the carbon nanotubes to obtain a carbon nanotube array. The method can conveniently obtain various combinations of isotope-doped carbon nanotube arrays by controlling the reaction temperatures of different carbon source gases and various carbon source gases according to actual needs, and further study of carbon nanotubes. Reaction mechanism.

In addition, the method for preparing the carbon nanotube array can obtain a plurality of different carbon source gases in different regions of the catalyst layer by controlling the temperature of the catalyst layer to achieve different reaction temperatures in different regions of the catalyst layer. Doping with different isotopes An array of sodium carbon tubes. Therefore, the preparation method can prepare a plurality of carbon nanotubes doped with different isotopes at one time, which reduces the preparation time. Moreover, the method can conveniently obtain an isotope-doped nano carbon tube array having various patterns by controlling the temperature of different regions of the catalyst layer.

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 those skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

30‧‧‧Nano Carbon Tube Array

32;34;36‧‧・Nano carbon pipe array

Claims (15)

A method for preparing a carbon nanotube array, comprising the steps of: providing a substrate formed with a catalyst layer, and placing the substrate formed with the catalyst layer into a reaction chamber; providing at least two carbon source gases, the at least two The carbon elements in the carbon source gas are respectively composed of different kinds of single carbon isotopes; and the at least two carbon source gases are simultaneously introduced into the reaction chamber, and the temperature of the catalyst layer is controlled to make different regions of the catalyst layer Different reaction temperatures are respectively achieved, and the at least two carbon source gases are reacted in different regions of the catalyst layer to form carbon nanotubes containing different kinds of carbon isotopes to form a carbon nanotube array. The method for producing a carbon nanotube array according to claim 1, wherein the material of the catalyst layer is selected from the group consisting of cobalt, nickel, iron, and any combination thereof. The method for producing a carbon nanotube array according to claim 1, wherein the at least two carbon source gases are selected from the group consisting of methane, ethylene, and acetylene. The method for producing a carbon nanotube array according to claim 1, wherein after the at least two carbon source gases are supplied, further comprising evacuating the reaction chamber and introducing a shielding gas of a predetermined pressure. The method for producing a carbon nanotube array according to claim 4, wherein the shielding gas is selected from the group consisting of helium, argon and nitrogen. The method for preparing a carbon nanotube array according to claim 1, wherein the temperature of the catalyst layer is controlled such that different regions of the catalyst layer respectively reach different reaction temperatures, and the at least two carbon source gases are in the catalyst. Layers occur in different areas The step of reacting is: controlling the entire region of the catalyst layer to a predetermined temperature to react one of the at least two carbon source gases; and additionally controlling at least one region of the catalyst layer to reach Different predetermined temperatures, and reacting a plurality of carbon source gases of the at least two carbon source gases in at least one region of the catalyst layer; forming a carbon carbon containing different kinds of carbon isotopes after a predetermined reaction time tube. The method for preparing a carbon nanotube array according to claim 1, wherein the temperature of the catalyst layer is controlled such that different regions of the catalyst layer respectively reach different reaction temperatures, and the at least two carbon source gases are in the catalyst. The steps of reacting different regions of the layer are: separately controlling the temperatures of at least two regions of the catalyst layer, respectively, so that at least two regions of the catalyst layer respectively reach different reaction temperatures, and at least two carbon source gases are in the catalyst. At least two regions of the layer react separately; after a predetermined time of reaction, carbon nanotubes containing different kinds of carbon isotopes are formed, respectively. The method for preparing a carbon nanotube array according to claim 1, wherein the method of controlling the temperature of the catalyst layer to achieve different reaction temperatures in different regions of the catalyst layer is: irradiating the device by at least one laser heating device The different regions of the catalyst layer are such that different regions of the catalyst layer respectively reach different temperatures. An embodiment of a carbon nanotube array prepared by the method for preparing a carbon nanotube array according to claim 1, wherein the carbon nanotube array is composed of an array of at least two nano carbon tubes, wherein At least two nano carbon tube arrays are each composed of carbon nanotubes containing different combinations of carbon isotopes. The carbon nanotube array according to claim 9, wherein the carbon isotope in the carbon nanotube comprises ¹² C, ¹³ C, ¹⁴ C or a combination of any two or more thereof. The carbon nanotube array according to claim 9, wherein the carbon nanotubes in the at least two nanocarbon tube arrays respectively contain different kinds of single carbon isotopes or a combination of different kinds of carbon isotopes. The carbon nanotube array of claim 9, wherein the at least two nanocarbon tube arrays are square, circular, elliptical or rectangular in shape. The carbon nanotube array according to claim 9, wherein the at least two nano carbon tube arrays are formed in a side by side manner or a nano carbon tube array surrounds another nano carbon tube array. Carbon tube array. The carbon nanotube array according to claim 9, wherein the carbon nanotubes in each nano carbon tube array are composed of a single carbon nanotube segment containing a single carbon isotope or a combination of different carbon isotopes. . The carbon nanotube array according to claim 9, wherein the carbon nanotubes in each nano carbon tube array are composed of a plurality of nanometers each having a different single carbon isotope or a different combination of different carbon isotopes. Carbon tube fragments.