WO2014071693A1

WO2014071693A1 - Single-walled carbon nanotube positioning and growing method

Info

Publication number: WO2014071693A1
Application number: PCT/CN2013/001356
Authority: WO
Inventors: 李彦; 秦校军; 彭飞; 杨娟
Original assignee: 北京大学
Priority date: 2012-11-08
Filing date: 2013-11-08
Publication date: 2014-05-15

Abstract

The present invention relates to a single-walled carbon nanotube positioning and growing method, capable of positioning and growing a single-walled carbon nanotube by disposing a catalyst for the growth of the single-walled carbon nanotube on a carrier having a positioning characteristic for the growth of the single-walled carbon nanotube, and fixing the carrier on a growth substrate; in particular, the metal oxides with the positioning characteristic have oxidation property, thus the present invention can also selectively position and grow the single-walled carbon nanotube.

Description

Positioning growth method of single-walled carbon nanotubes

Technical field

The present invention relates to single-walled carbon nanotubes, and more particularly to a method for growing single-walled carbon nanotubes, and more particularly to a method for positioning growth of semiconducting single-walled carbon nanotubes. Background technique

As a typical nanomaterial, carbon nanotubes, especially single-walled carbon nanotubes (SWNTs), have become the focus of today's research due to their excellent performance.

Single-walled carbon nanotubes have a high aspect ratio and are typical one-dimensional nanomaterials. Single-walled carbon nanotubes consisting of a graphite layer rolled into a cylindrical shape have an extremely high aspect ratio. This special tubular structure determines the excellent physical, chemical, electrical and mechanical properties of carbon nanotubes, such as: High Young's modulus, tensile strength and thermal conductivity, ideal one-dimensional quantum wire and direct bandgap optical properties, can modify other molecules and have good biocompatibility. These advantages give carbon nanotubes a broader application prospect in many fields such as nanoelectronic devices, optical devices, chemical biosensors, and composite materials than caged fullerene molecules with relatively single structures.

According to the currently reported growth method, single-walled carbon nanotubes can only grow randomly, and it is not possible to perform local growth. The single-walled carbon nanotubes that are positioned and grown will bring great convenience to their applications, and the device production will be more convenient. Therefore, development of a method for positioning growth of single-walled carbon nanotubes is expected.

In particular, single-walled carbon nanotubes can be classified into two types according to their different conductivity: metallic single-walled carbon nanotubes and semiconducting single-walled carbon nanotubes. When the Brillouin zone of the carbon nanotube passes through the K _B point of the graphene Brillouin zone (ie, the Fermi level), the single-walled carbon nanotube exhibits metallicity; when the Brillouin zone of the carbon nanotube Single-walled carbon nanotubes exhibit semiconductivity when they do not pass the K _B point of the graphene Brillouin zone.

Semiconducting single-walled carbon nanotubes can be used as a basic unit for constructing nano-scale logic circuits, such as field effect transistors, p-n junction diodes, and memory devices, and have broad application space and prospects. The control of high-purity semiconducting single-walled carbon nanotubes is the core technology in the field of carbon nanotube research. There are two ways to obtain a single-conducting single-walled carbon nanotube, one is a method of separation after preparation, and the other is a method of direct growth. The method of separation after preparation is usually cumbersome and easy to have impurities, so the development of a method for directly growing single-walled single-walled carbon nanotubes is undoubtedly more worthy of attention.

At present, the methods for directly growing single-conducting single-walled carbon nanotubes reported in the literature can be divided into two categories: one is to obtain a single conductive carbon nanotube by selecting a suitable catalyst or to make one or several The chiral carbon nanotubes are enriched; the other is the destruction of a certain conductive single-walled carbon nanotube by using the different reactivity of the metallic single-walled carbon nanotubes and the semiconducting single-walled carbon nanotubes, preventing It grows to obtain another electrically conductive single-walled carbon nanotube.

Since the metallic carbon nanotubes have lower ionization energy than the semiconducting carbon nanotubes and are more susceptible to chemical reactions such as oxidation, it is possible to selectively prevent and destroy the growth of the metallic carbon nanotubes, thereby obtaining a sample of the semiconducting carbon nanotubes. . It has been studied to selectively prevent the growth of metallic carbon nanotubes by adding or generating certain reactive species in the gas phase. However, these methods have the disadvantage that the conditions are not easy to control and the growth window is narrow.

In addition, most of the selective growth is carried out by bulk growth, and a powder sample of single-walled carbon nanotubes is obtained, which easily forms a bundle of carbon nanotubes. These samples also need to be purified before they can be utilized. The carbon nanotubes must be dispersed and assembled onto the surface of the substrate during device fabrication. Purification and dispersion processes inevitably use ultrasound and add dispersant. Description

Single-walled carbon nanotubes introduce defects, resulting in a decrease in their performance. The process of assembly to the surface of the substrate is a significant challenge to the direction and position control of single-walled carbon nanotubes. The method of selectively preparing a single conductivity directly on the surface of the substrate is undoubtedly the most convenient for subsequent device fabrication because it avoids the process of purging, dispersing, and assembling the carbon nanotubes.

Therefore, there is a need to develop a more efficient and reliable method for growing semiconducting carbon nanotubes, particularly a method for positioning growth of semiconducting carbon nanotubes. Summary of the invention

In order to solve the above problems, the inventors conducted intensive studies and found that: some metal oxides and non-metal oxides have locating properties for the growth of single-walled carbon nanotubes, and are supported by a catalyst for growing single-walled carbon nanotubes. The carrier of the localization property is fixed on the growth substrate, and the single-walled carbon nanotubes can be positioned and positioned; in particular, the metal oxides having the localization characteristics are oxidative, and the single-wall carbon can be selectively positioned and grown. Nanotubes, thereby completing the present invention.

A first aspect of the present invention provides a method for positioning growth of single-walled carbon nanotubes, the method comprising the steps of:

(1) Providing an oxide carrier having a positioning property: providing a metal oxide or a non-metal oxide powder having a particle diameter of 1 nm - 1 000 μm, the metal oxide being selected from the group consisting of Ce0 ₂ , A1 ₂ 0 ₃ , MgO _{_{_{, V 2 0 5, Mn0 2}}} , Cr 2 0 3, Zr0 2, Hf0 2, Sn0 2, Pb0 2, La 2 0 3, Y 2 0 3, praseodymium oxide _{(Pr x O "), Eu} 2 0 3, Gd ₂ 0 ₃ and uranium oxide (U _x O,), the non-metal oxide is Si0 ₂ ;

(2) Catalyst (load of precursor Γ: The oxide carrier having the locating property obtained in the step (1) and the catalyst nanoparticle or the catalyst precursor are dispersed in a solvent, sonicated, the upper layer is discarded, and the separation is dried. A catalyst (precursor) powder supported by an oxide carrier is obtained: (3) administration of an oxide carrier loaded with a catalyst (precursor): an oxide carrier loaded with a catalyst (precursor) is subjected to photolithography, sputtering, Evaporation, microcontact printing, nanoimprinting or squeegee etching on the growth substrate;

(4) CVD growth of single-walled carbon nanotubes: The growth substrate obtained in the step (3) is pre-reduced with hydrogen at a temperature of 600-1 500 ° C, and then 10 - 1 000 ml / The flow rate of the carbon source gas, optionally, with the introduction of hydrogen, by chemical vapor deposition, grows single-walled carbon nanotubes.

A second aspect of the present invention provides a method for positioning growth of single-walled carbon nanotubes, the method comprising the steps of:

(1) Providing an oxide carrier having a positioning property: providing a metal oxide or a non-metal oxide powder having a particle diameter of from 1 nm to 1 000 μm, the metal oxide being selected from the group consisting of Ce0 ₂ , A1 ₂ 0 ₃ , MgO _{_{_{, V 2 0 5, Mn0 2}}} , Cr 2 0 3, Zr0 2, Hf0 2, Sn0 2, Pb0 2, La 2 0 3, Y 2 0 3, praseodymium oxide _{_{(PrxO - Eu 2 0 3,}} Gd 2 0 3 And uranium oxide ( U _x O _y ) , the non-metal oxide is Si0 ₂ ;

(2) the deposition of the oxide carrier: the above oxide carrier is deposited on the growth substrate by photolithography, sputtering, evaporation, microcontact printing, nanoimprinting or squeegee etching;

(3) deposition of a catalyst: on the growth substrate obtained in the above step (2), depositing a catalyst on the oxide support in the growth substrate by vapor-depositing metal catalyst particles or the like; (4) single-walled carbon nanotubes CVD growth: the growth substrate obtained in the step (3) is grown at a flow rate of 10 to 1 000 ml/min, optionally with hydrogen gas, by chemical vapor deposition, to grow single-wall carbon nanotube.

A third aspect of the present invention provides a method for positioning growth of a semiconducting single-walled carbon nanotube, the method comprising the steps of:

(1) Providing an oxide carrier having a positioning property: providing a metal oxide having a particle diameter of 1 nm - 1 000 μm, the metal oxide being selected from the group consisting of Ce0 ₂ , V ₂ 0 ₅ , Mn0 ₂ , Cr ₂ 0 ₃ , Zr0 ₂ , Hf0 ₂ , Instruction manual

Sn〇 ₂ , Pb0 ₂ , La ₂ 0 ₃ , Y ₂ 0 ₃ , praseodymium (Pr _x O _y ), Eu ₂ 0 ₃ , Gd ₂ 0 ₃ and uranium oxide (U, 0,); ( 2 ) catalyst ( Precursor loading: The oxide carrier having the positioning property obtained in the step (1) and the catalyst nanoparticle or the catalyst precursor are dispersed in a solvent, sonicated, the upper layer is discarded, and separated and dried to obtain an oxide carrier. Supported catalyst (precursor) powder; (3) delivery of oxide carrier with catalyst (precursor): catalyst

The (precursor) oxide carrier is deposited on the growth substrate by photolithography, sputtering, evaporation, microcontact printing, nanoimprinting or squeegee etching;

(4) CVD growth of single-walled carbon nanotubes: the growth substrate obtained in the step (3) is pre-reduced with hydrogen at a temperature of 600-1500 ° C, and then 10-1000 ml/min. The flow rate carbon source gas, optionally with the introduction of hydrogen, is grown by chemical vapor deposition to grow single-walled carbon nanotubes.

A fourth aspect of the invention resides in a method of locating a semiconductor single-walled carbon nanotube, the method comprising the steps of:

(1) Providing an oxide carrier having a positioning property: providing a metal oxide having a particle diameter of 1 nm - ΙΟΟΟμ Γη, the metal oxide being selected from the group consisting of Ce0 ₂ , V ₂ 0 ₅ , Mn0 ₂ , Cr ₂ 0 ₃ , Zr0 ₂ , Hf0 ₂ , Sn0 ₂ , Pb0 ₂ , La ₂ 0 ₃ , Y ₂ 0 ₃ , yttrium oxide (Pr _x O _y ), Eu ₂ 0 ₃ , Gd ₂ 0 ₃ and uranium oxide (U, 0,);

(2) The placement of the oxide carrier: the above oxide carrier is deposited on the growth substrate by photolithography, sputtering, evaporation, microcontact printing, nanoimprinting or squeegee etching;

(3) deposition of a catalyst: on the growth substrate obtained in the above step (2), depositing a catalyst on the oxide support in the growth substrate by vapor-depositing metal catalyst particles or the like; (4) single-walled carbon nanotubes CVD growth: the growth substrate obtained in the step (3) is grown at a flow rate of 10 to 1000 ml/min, optionally with hydrogen gas, to grow single-walled carbon nanotubes by chemical vapor deposition. .

A fifth aspect of the present invention provides a method for preparing a semiconducting single-walled carbon nanotube, the method comprising the steps of:

(1) cleaning the quartz, silicon wafer or ceramic substrate;

(2) Preparation of oxide carrier: hydrolysis reaction of soluble nitrate with sodium hydroxide of metal Ce, V, Mn, Cr, Zr, Hf, Sn, Pb, La, Y, Pr, Eu and Gd, using water prepared as follows hot synthesis of metal _{_{_{oxide: Ce0 2, V 2 0 5}}} , Mn0 2, Cr 2 0 3, Zr0 2, Hf0 2, Sn0 2, Pb0 2, La 2 0 3, Y 2 0 3, praseodymium oxide (Pr _x O _y ). Eu ₂ 0 ₃ and Gd ₂ 0 ₃ , the product is washed by water and centrifuged for use;

(3) Supporting of the catalyst: dispersing the oxide carrier obtained in the step (2) with the catalyst nanoparticles or the catalyst precursor in a solvent, sonicating, discarding the upper layer, and separating and drying to obtain a catalyst supported by the oxide carrier ( Precursor) powder;

(4) Preparation of a catalyst (precursor) solution supported by an oxide carrier: The oxide carrier-supported catalyst (precursor) powder obtained in the step (3) is dispersed in a solvent to obtain an oxide carrier load. Catalytic (precursor) solution;

(5) CVD growth of semiconductor-selective single-walled carbon nanotubes: the oxide carrier-supported catalyst (precursor) powder prepared in the step (3) is placed in a ceramic or quartz boat-like or disk-shaped base container, Alternatively, the oxide carrier-supported catalyst (precursor) solution obtained in the step (4) is dropwise added to a silicon wafer, a quartz or a ceramic substrate, and optionally subjected to hydrogen gas at a temperature of 600 to 1500 ° C for prereduction. Then, the single-walled carbon nanotubes are grown by chemical vapor deposition (CVD) with a carbon source gas at a flow rate of 10 to 1000 ml/min, optionally with the introduction of hydrogen.

In the method according to the invention, the single-walled carbon nanotubes are grown on the oxide supported or deposited catalyst, which is difficult or hardly at other locations on the growth substrate, and therefore can be positioned by positioning the oxide support. Growth of single-walled carbon nanotubes. Instruction manual

Further, in the case of using a metal oxide carrier, it is possible to selectively position and grow semi-conductive single-walled carbon nanotubes, and the results of Raman spectroscopy show that the selectivity of the semiconducting single-walled carbon nanotubes is very good. DRAWINGS

Figure 1 shows a obtained in Example 1 serving catalyst precursor planted negative optical micrograph of Fe (N0 _₃₎ C ₃ to e0 ₂ powder.

Fig. 2 shows a S EM photograph of the carbon nanotube obtained in Example 1.

Figure 3a shows the Raman spectrum of the carbon nanotubes obtained in the examples.

Figure 3b shows the Raman spectrum of the carbon nanotubes obtained in the examples.

Fig. 4 shows a S EM photograph of the carbon nanotube obtained in Example 3.

Figure 5a shows the Raman spectrum of the carbon nanotubes obtained in Example 3.

Fig. 5b shows the Raman spectrum of the carbon nanotubes obtained in Example 3.

Figure 6 shows an optical micrograph e0 ₂ powder serving the loaded catalyst precursor Fe C (N0 _{₃₎ 3} obtained in Example 4.

Fig. 7 shows a S EM photograph of the carbon nanotube obtained in Example 4.

Fig. 8a shows the Raman pupil of the carbon nanotube obtained in Example 4.

Fig. 8b shows the Raman spectrum of the carbon nanotubes obtained in Example 4.

Fig. 9 shows a S EM photograph of the carbon nanotube obtained in Example 5.

Figure 10a shows the Raman spectrum of the carbon nanotubes obtained in Example 5.

Fig. 1 Ob shows the Raman optical term of the carbon nanotube obtained in Example 5.

Fig. 1 1 shows a S EM photograph of the carbon nanotube obtained in Comparative Example 1.

Fig. 1 2a shows the Raman spectrum of the carbon nanotube obtained in Comparative Example 1.

Fig. 1 2b shows the Raman spectrum of the carbon nanotube obtained in Comparative Example 1. detailed description

The features and advantages of the present invention will become more apparent from the aspects of the invention.

In the present invention, the positioning property of the oxide carrier is mainly utilized, and two methods are employed for this purpose. First, after the catalyst (precursor) is supported on the oxide carrier, the oxide carrier supporting the catalyst (precursor) is used. The carbon nanotubes are deposited on the growth substrate, and then the carbon nanotubes are grown. Second, the oxide carrier is placed on the growth substrate, and then the catalyst is deposited on the oxide carrier which has been placed on the growth substrate, and then the carbon nanotubes are grown.

Human study found that the present invention, as the metal oxide support such as oxides _{_{_{Ce0 2, A1 2 0 3,}}} MgO, V 2 0 5, Mn〇 _{_{_{2, Cr 2 0 3, Zr0}}} 2, Hf0 2, Sn0 2, Pb0 2 , La ₂ 0 ₃ , Y ₂ 0 ₃ , praseodymium oxide (Pr _x O _v ), Eu ₂ 0 ₃ , Gd ₂ 0 ₃ , uranium oxide (U, O _y ) or non-metal oxides such as SiO ₂ for single-walled carbon The growth of nanotubes has localization characteristics. When it is used to support catalysts for carbon nanotube growth, such metal oxides or non-metal oxides can be grown with single-walled carbon nanotubes at high temperatures. Tightly bonded, no positional movement occurs on the growth substrate during the growth of the single-walled carbon nanotubes, so that the single-walled carbon nanotubes can be positioned and grown. However, the above mechanism is only speculated on the possibility of the present invention, and the present invention is not limited thereto. In particular, when only a catalyst was used without using an oxide carrier, single-walled carbon nanotubes were not found to have localized growth specificity, and the results of the study indicate that only single-walled carbon nanotubes were not grown by using a catalyst.

In the present invention, among the metal metal oxides used, ruthenium oxide (Pr _x O _y ) means a gas of a metal ruthenium, wherein X and y represent the number of metal ruthenium atoms and oxygen atoms in the ruthenium oxide chemical formula, respectively. The number, X * valence valence = 2v _; as ruthenium oxide (Pr _x O _y ^ 々 example, mention Pr ₂ 0 ₃ , Pr ₆ O n . Pr ₃ 0 ₄ and the like.

In the present invention, among the metal metal oxides used, uranium oxide (u _x o,.) refers to an oxide of metal uranium, wherein X and y represent the number of metal uranium atoms and oxygen atoms in the uranium oxide chemical formula, respectively. The number of X * uranium valence = 2y. As an example of uranium oxide, mention U0 ₂ , U ₂ 0 ₅ , U ₃ 0 ₇ , U ₃ 0 ₈ ,

UO; etc.

Furthermore, human studies found that the present invention, the oxide support such as metal oxides _{_{_{Ce0 2, V 2 0 5,}}} Mn0 2, Cr 2 0 3, Zr0 2, Hf0 2, Sn0 2, Pb0 2, La 2 0 3 , Y ₂ 0 ₃ , yttrium oxide (Pr, 0,), Eu ₂ 0 ₃ , Gd ₂ 0 ₃ and uranium oxide (U., O _v ) also have oxygen storage capacity, when used to support carbon nanotube growth When a catalyst is used, the semiconductor single-walled carbon nanotubes can be selectively positioned and grown. However, when only an oxide carrier is used and only a catalyst is used, it has not been found that the prepared single-walled carbon nanotube has conductivity selectivity, and the results of the study indicate that the use of a catalyst alone does not selectively obtain a semiconducting single-wall carbon. nanotube. Say

Further, the inventors have also found that when the catalyst for carbon nanotube growth is supported on the oxide carrier, the catalyst is not in direct contact with the growth substrate, and the oxide functions as a barrier catalyst and a substrate, thereby, as a carbon source. When the cracking nucleates on the surface of the catalyst particle to grow carbon nanotubes, the carbon nanotubes are suspended on the surface of the substrate, which is more susceptible to the influence of the gas flow and grows in the direction of the gas flow to form carbon nanotubes oriented in the direction of the gas flow. That is, carbon nanotubes having orientation selectivity are obtained. In contrast, in the case where only the catalyst is used without using the oxide carrier, since the catalyst is directly dropped on the substrate, the surface of the substrate is not very clean, and obvious catalyst carrier particles can be seen, and generally obtained Non-oriented carbon nanotubes.

In the present invention, the inventors have found through research and a large number of experiments that among a large number of metal oxides, Ce0 ₂ , A1 ₂ 0 ₃ , MgO, V ₂ 0 ₅ , Mn0 ₂ , Cr ₂ 0 ₃ , Zr0 ₂ , Hf0 ₂ , Sn0 ₂ , Pb0 ₂ , La ₂ 0 ₃ , Y ₂ 0 ₃ , yttrium oxide (Pr _x O,), Eu ₂ 0 ₃ , Gd ₂ 0 ₃ and uranium oxide ( U _x O _v ) are suitable as oxides The carrier, which helps to selectively position and grow semiconducting carbon nanotubes, in particular Ce0 ₂ , has a very obvious effect of selectively positioning and growing semiconducting carbon nanotubes: in non-metal oxides, Si0 _{2 is} for carbon nanotubes. Growth has positioning characteristics.

Specifically, as the uranium oxide U _x O, an oxide of the isotope ²³⁸ U is used.

In the present invention, as the oxide carrier, any one of the above metal oxides and non-metal oxides may be used, or two or more of them may be used in combination.

In the present invention, as the oxide carrier, the particle diameter is suitably in the range of 1 nm to 1 000 μm, that is, the nano- or micro-scale oxide powder is suitable as an oxide carrier. Specifically, the oxide carrier has a particle diameter of 1 Onm - 1 μm.

In order to obtain an oxide carrier suitable for supporting a catalyst, a nano- or micro-scale oxide powder may be directly synthesized by a chemical reaction method, or a nano- or micro-scale oxide powder may be obtained by grinding large oxide particles, a bulk or the like.

For example, as a chemical reaction method, the following metal oxides can be prepared by a hydrothermal synthesis method by a hydrolysis reaction of a soluble nitrate of each metal with sodium hydride: Ce0 ₂ , A1 ₂ 0 ₃ , MgO, V ₂ 〇 ₅ _{_{_{, Mn0 2, Cr 2 0 3}}} , Zr0 2, Hf0 2 -. Sn0 2, Pb0 2, La 2 0 3, Y 2 0 3, praseodymium oxide _{(PrxC ^) E u 2 0} 3, Gd 2 0 3 oxide Uranium (U _x O _y ), the product can be ground by washing and centrifuging.

In a preferred embodiment, in the case of using a Ce0 ₂ carrier, the soluble Ce salt solution may be mixed with a soluble inorganic base solution, reacted at a temperature of 25-24 CTC, and dried to obtain a Ce0 ₂ support.

Further preferably, as the soluble Ce ^{3 +} salt, a nitrate, a chloride, a sulfate, an acetate or the like can be used. Preferably, Ce(N0 ₃ ); 6H ₂ 0 is used. Instruction manual

Further preferably, as the soluble inorganic base, NaOH or KOH can be used. Any one of them may be used, or any combination of the two may be used.

In a preferred embodiment of the step (2) of the method for producing a semiconducting single-walled carbon nanotube according to the present invention, the reaction temperature of the soluble Ce ^{3 +} salt solution and the soluble inorganic alkali solution is 25-240, preferably 166-200 °. C, particularly preferably about 1 80 °C. If the reaction temperature is lower than 25 ° C, it is difficult to form Ce0 ₂ , and if the reaction temperature is higher than 240 ° C, the performance of the obtained CeO ₂ carrier deteriorates.

In the present invention, as the catalyst, a conventional catalyst for carbon nanotube growth such as iron, copper, lead, nickel, cobalt, manganese, chromium or molybdenum or the like can be used. In the present invention, as the catalyst, a powder of these catalyst metals or a powder of a catalyst precursor may be used, which is supported on an oxide carrier and then placed on a growth substrate; or these catalyst metals may be used as they are. The catalyst metal is deposited directly on the oxide support on the growth substrate.

As used herein, the term "catalyst (precursor)" means a catalyst and a catalyst precursor. The catalyst is a carbon nanotube growth catalyst such as iron, copper, lead, nickel, cobalt, manganese, chromium or molybdenum, and the catalyst precursor is reactable to obtain a carbon nanotube growth catalyst such as iron, copper, lead, nickel, Cobalt, manganese, chromium or molybdenum soluble salts such as iron, copper, lead, nickel, cobalt, manganese, chromium or molybdenum oxides or nitrates, chlorides, sulfates, acetates, such as Fe(N0 ₃ ) ₃ '9H ₂ 0, FeC l 6H ₂ 0, CuCl ₂ , Cu(N0 ₃ ) ₂ -3H ₂ 0, (CH ₃ COO) ₂ Pb, Pb(N0 ₃ ) ₂ , NiCl ₂ -6H ₂ 0, Co(N0 ₃ ) ₂ '6H ₂ 0, (CH ₃ COO) ₂ Co-4H ₂ 0, MnCl ₂ , MnS0 ₄ , CrCl ₃ , (ΝΗ ₄ ) ₆ Μο ₇ 0 ₂₄ ·4Η ₂ 0 and the like.

As the catalyst precursor, specifically, for example, an iron salt such as Ce(N0 ₃ ) 3 -6H ₂ 0 , Fe(N0 ₃ ) ₃ -9H ₂ 0, FeC l ₃ '6H ₂ 0 ; a copper salt such as CuCl ₂ , Cu(N0 ₃ ) ₂ 3 H ₂ 0, (CH ₃ COO) ₂ Pb ; a lead salt such as Pb(N0 ₃ ) ₂ ; a nickel salt such as NiCl ₂ '6H ₂ 0 ; a cobalt salt such as Co(N0 ₃ ) ₂ '6H ₂ 0 , ( CH ₃ COO) ₂ Co-4H ₂ 0 : manganese salt, such as MnCl ₂ , MnS0 ₄ ; chromium salt, such as CrCl ₃ ; molybdenum salt, such as (Ν Η ₄ ) (, Μο ₇ 0 ₂₄ · 4Η ₂ 0 and so on.

According to the first and third aspects of the present invention, the oxide support and the catalyst (precursor) powder are dissolved in an organic solvent, sonicated, the upper layer is discarded, and separated and dried to obtain an oxide supported catalyst (precursor). body).

Among them, as the solvent, an inorganic solvent such as water or an organic solvent such as an alcohol solvent such as ethanol, decyl alcohol, ethylene glycol or the like, or acetone or furfural may be used. Any one of them may be used, or a plurality of them may be used in combination.

Studies have shown that sonication helps the catalyst (precursor) to be well supported on the oxide support. It has been found through experiments that the sonication time is preferably from 10 to 40 minutes, more preferably from 1 to 5 to 30 minutes, particularly preferably from about 20 minutes. If the sonication time is less than 10 minutes, it may cause uneven dispersion of the catalyst (precursor). If the sonication time exceeds 40 minutes, the dispersion effect is hardly improved.

Alternatively, in the first and third aspects according to the present invention, the combination of steps (1) and (2) may be replaced by:

For a metal oxide having localization characteristics, a nitrate solution of the metal or a mixed solution with a catalyst precursor is provided; or

For the non-metal oxide having the positioning property, a mixed solution containing the ester of the non-metal silicon and the catalytic precursor is provided.

Among them, as the solvent of the mixed solution, an inorganic solvent such as water or an organic solvent such as an alcohol such as ethanol, decyl alcohol, ethylene glycol or the like, or acetone or furfural may be used. Any one of them may be used, or a plurality of them may be used in combination. It is preferred to use ethanol.

As the ester containing non-metal silicon, a silicate such as an alkyl silicate chain ester can be used, and for example, (n-)ethyl silicate, (n-) yttrium silicate, tetrakis (octadecyl) silicate can be mentioned. Ester and the like.

For oxide carriers loaded with a catalyst (precursor), such as by photolithography, splashing Injection, evaporation, microcontact printing, nanoimprinting or squeegee etching are applied to the growth substrate. Photolithography, sputtering, evaporation, microcontact printing, nanoimprinting, or squeegee etching are all conventional positioning methods, which have been disclosed or disclosed in the prior art.

Example: 4, 5! For lithography: Jie Liu et al., Advanced Materials 2003, 15. 165 1655; For sputtering: Refer to Y. Awano et al., Phys. Stat. Sol. (A 2006. 203.

3611 -3616; For evaporation: Reference J. Robertson et al., Phys. Rev. B 2012. 85.

235411; 于1 Contact worm pressure t'p mode: Reference Yan Li et al.. Chemistry of Materials 2006.

18. 4109-4114 Ten nanoimprinting method: Reference Jae K. Hwang et al., Nat. Nanotech.

2010. 5. 742-748; Ten in the pen 3⁄4'] Candle method: Reference Hua Zhang et al., Che. Soc. Rev. 2011. 40, 5221-5231.

In particular, in the present invention, micron-level positioning control can be realized by sputtering, evaporation, and microcontact printing, and nano-level positioning control can be realized by photolithography, nanoimprinting, or squeegee etching. Say

Depending on the specific needs, you can choose a specific positioning method, which is not particularly limited. ―

According to the second aspect of the present invention, the oxide book carrier is placed on the growth substrate by means of, for example, photolithography, sputtering, evaporation, microcontact printing, nanoimprinting or squeegee etching, and then by CVD or the like. A catalyst is deposited.

The deposition of a catalyst by means of CVD or the like is a conventional metal deposition method. For example, in a CVD process, a catalyst precursor solution (such as a CuCl ₂ ethanol solution) on a slide (usually a silicon wafer) for supporting a growth substrate is first converted into an oxide of a catalyst metal (such as CuO, etc.) in air. Then, it is reduced to a metal (such as Cu or the like) by a reducing component in the growth gas or hydrogen in the pre-reduction step. At the growth temperature, some low-boiling metal catalyst particles (such as Cu, etc.) are volatilized throughout the quartz tube. Since the surface of the oxide support used in the present invention is rough, these metal catalyst particles are selectively deposited on the surface of the oxide support during the pre-reduction process or growth process, instead of growing the surface of other smooth portions of the substrate, thereby realizing the metal catalyst. Positioning deposition.

In the method for producing a semiconducting single-walled carbon nanotube according to the fifth aspect of the present invention, the object of the step (4) is to dispose the oxide carrier of the supported catalyst (precursor) as a solution, which can be directly added to the growth. On the substrate, used to grow carbon nanotubes.

In the present invention, carbon nanotubes are grown by chemical vapor deposition (CVD) techniques.

As the growth substrate (also referred to as a growth substrate), a conventional growth substrate such as ceramic, silicon wafer, quartz, sapphire or the like can be used, and there is no particular limitation thereto. However, as the substrate, a p-type heavily doped silicon wafer is preferably used, and further preferably, the surface thereof may be formed into a silicon oxide layer of several hundred nanometers, for example, 500 nm thick by a thermal oxidation method.

For the growth substrate, it can be cleaned using conventional methods, for example, by ultrasonication, before use.

In particular, for the treatment of a p-type heavily doped silicon wafer substrate, the silicon wafer may be thinned with a glass knife and impregnated with a mixed solution of concentrated sulphuric acid and hydrogen peroxide, for example, a thick stone charge of 7:3 by volume. a mixed solution of acid and hydrogen peroxide (also referred to as "Piranha solution"), and heat-heated at a temperature of 90-15 CTC, preferably 110-130 ° C, more preferably about 120 ° C, to hydroxylate the surface of the silicon wafer, which is more hydrophilic , to facilitate the dispersion of the subsequent catalyst. Preferably, the heating and holding time is from 10 to 60 minutes, more preferably from 15 to 30 minutes. For washing and drying, for example, the substrate may be repeatedly washed with ethanol and ultrapure water in sequence, and blown with N ₂ gas.

If a catalyst precursor is used, the catalyst may be pre-reduced with hydrogen prior to the introduction of the carbon source gas, so that the catalytic precursor is reacted to obtain a catalyst, however, due to the growth of the carbon nanotubes Description

When hydrogen is generally supplied for assisted growth, the catalyst may not be pre-reduced; if the catalyst itself is used, the hydrogen pre-reduction process is not required. However, the pre-reduction of hydrogen gas at this time has an influence on the conductivity selectivity of the obtained carbon nanotubes, and if the pre-reduction time is too long, the obtained carbon nanotubes do not have conductivity selectivity. The reason for this may be that: the pre-reduction process may cause some or all of the oxide support to be reduced, reduce its oxygen storage capacity, and weaken its oxidizing ability, so that it cannot be used when the single-walled carbon nanotubes grow from the catalyst surface. Metallic single-walled carbon nanotubes are removed by oxidation. Preferably, the pre-reduction of hydrogen gas is carried out for no more than 15 minutes, more preferably less than 5 minutes.

In the chemical vapor deposition technique of the present invention, as the carbon source gas, decane, ethanol, an ethylene block or the like is used. Preferably, methane is used. The inventors have found that when other carbon source gases are used, only a small amount of carbon nanotubes can be obtained, and even carbon nanotubes cannot be obtained. However, the reason for this is not clear.

In the method according to the present invention, the temperature at which the single-walled carbon nanotubes are grown by chemical vapor deposition is 600 to 1500 ° C, preferably 700 to 1300 Å, more preferably 900 to 】 100 ° C. Within the temperature range, the desired single-walled carbon nanotubes can be positioned to grow. If the temperature is lower than 600 ° C, the carbon source gas will be cleaved into amorphous carbon or multi-walled carbon nanotubes due to the too low growth temperature; conversely, if the temperature is higher than 1500 ° C, the catalyst will be caused by excessive temperature. The activity is reduced, which in turn affects the catalytic effect, the conductivity selectivity is lowered, and it is difficult to grow single-walled carbon nanotubes. It is also possible that the carbon source is strongly decomposed due to high temperature, which poisons the catalyst and is not conducive to carbon tube nucleation growth.

In the process according to the invention, the carbon source gas has a flow rate of from 10 to 1000 ml/min, preferably from 10 to 800 ml/min, still more preferably from 300 to 500 ml/min. When the carbon source gas flow rate is within this range, it is more suitable for positioning and growing carbon nanotube growth. Moreover, in the case of using a metal oxide support, the resulting carbon nanotubes have a desired conductivity selectivity. If the flow rate of the carbon source gas is higher than 1000 ml/min, the carbon supply rate will be too large, and amorphous carbon will be formed to entrap the catalyst and cause poisoning; on the contrary, if the carbon source gas flow rate is lower than 10 ml/min, the carbon supply rate is reduced. Small, unable to meet the carbon supply rate of the growth of semiconducting carbon tubes.

In the method according to the present invention, in the case of performing chemical vapor deposition, it is preferred to assist in the growth of single-walled carbon nanotubes by the passage of hydrogen gas into the carbon source gas, which acts as a reducing atmosphere and maintains the chemical equilibrium of the carbon nanotube growth process.

However, in order to avoid the hydrogen reduction of the oxide support and thus the positioning growth and even the conductivity selectivity of the carbon nanotubes, the flow rate of hydrogen accompanying the introduction cannot be excessively high. Preferably, the hydrogen flow rate is controlled to be less than 150 ml/min, more preferably less than 100 ml/min.

In the method of the present invention, the growth time is not particularly limited as long as it can satisfy the single-walled carbon nanotubes which can be grown to have conductivity selectivity. However, the growth time is preferably 5-60 min, more preferably 15-30 min. This is because if the growth time is too short, the growth of the single-walled carbon nanotubes may be insufficient, and if the growth time is too long, the reaction materials and time are wasted.

In the method of the present invention, the reaction vessel for performing chemical vapor deposition is not particularly limited, and a reaction vessel commonly used in the art, such as a quartz tube, may be used.

After the growth is completed, post-treatment can be carried out, for example, by reducing the temperature in a reducing gas such as hydrogen and/or an inert gas atmosphere. These post-processing are known in the art and will not be described here.

Example

Example 1 Positioning Growth of Semiconducting Single-walled Carbon Nanotubes

A p-type heavily doped silicon wafer is used, and the crystal plane is Si (100). The surface is thermally oxidized to form a silicon dioxide layer of about 500 nm thick. Use a glass knife to divide the silicon wafer into 5 mm χ 5 mm pieces and place them in a Piranha solution (a 7:3 mixed solution of concentrated acid and hydrogen peroxide) and heat at 120 °C for 20 minutes to make the surface of the silicon wafer. Hydroxylated, more hydrophilic, facilitates dispersion of the catalyst. Then, it was washed repeatedly with ethanol and ultrapure water (resistivity 18.2 ΜΩ 'cm), and dried with N ₂ gas. Instruction manual

A Si0 ₂ /Si substrate was obtained.

0.71 g of Ce(N0 ₃ ) 3 · 6H ₂ 0 (1.64 mmol) and 1.35 g of NaOH (33.75 mmol) were weighed and dissolved in 5 ml of H ₂ 0 and 35 ml of H ₂ 0, respectively, and then the two solutions were mixed and stirred at room temperature. After 2 hours, it was placed in a reaction vessel, and reacted at 180 C for 24 hours. After the completion of the reaction, the sample was separated by centrifugation (7000 rpm), washed three times with H ₂ 0, washed once with ethanol, and then placed in an oven for drying to obtain a Ce0 ₂ powder having a particle diameter of 10 to 100 nm.

Weigh 0.0592g of the above prepared Ce0 ₂ , force into the mouth of 0.0479g of Fe(N0 ₃ ) ₃ - 9H ₂ 0 and 10ml of ethanol, after sonication for 20 minutes, let stand for 2 hours, discard most of the supernatant, in the oven Dry in the middle. The dried sample was ultrasonically washed with 20 ml of 0 ethanol, centrifuged at 7000 rpm, and the ethanol solution was discarded. After repeated 3 times, it was dried in an 8 CTC oven to obtain CeO, powder loaded with the catalyst precursor Fe(N0 ₃ ) ₃ .

1 Omg of Ce0 ₂ powder loaded with the catalyst precursor Fe(N0 ₃ ) ₃ was added, and 2 mL of ethanol was added to prepare a catalyst precursor suspension. Use a micro-sampler to draw 5 μL of the suspended droplets onto the surface of the PDMS stamp with convex stripes. After drying, the stamp is imprinted on the surface of the Si0 ₂ /Si substrate, and then heated in air for 15 minutes to obtain Ce0 _{2 .} Powder loaded catalyst precursor stripes. An optical micrograph of the obtained CeO ₂ powder loaded with the supported catalyst precursor Fe(N0 ₃ ) ₃ is shown in FIG. 1 . As can be seen from Fig. 1, the Ce0 ₂ powder of the supported catalyst precursor is preferably arranged on the surface of the Si ₂ /Si substrate in accordance with the stamp pattern, and the positioning to the micron level is achieved on the surface of the substrate.

The obtained growth substrate was placed in a quartz tube (inner diameter 2.5 cm) of a tube furnace, heated to 700 ° C in air, and then pushed into the heating center. After burning for 5 minutes, the temperature was raised to 950 Torr by Ar protection. After reaching the temperature, Ar was switched to 100 sccm H ₂ and passed through 400 sccm CH _{4 for} 15 minutes, and then cooled to room temperature under Ar atmosphere to obtain carbon nanotubes.

A SEM photograph of the obtained carbon nanotubes is shown in Fig. 2 . It can be seen from FIG. 2 that the single-walled carbon nanotubes are locally grown in the CeO ₂ powder region on which the growth substrate is imprinted with the supported catalyst precursor, thereby realizing the localized growth of the single-walled carbon nanotubes. .

The Raman spectrum of the obtained carbon nanotubes is shown in Figs. 3a and 3b, wherein Fig. 3a shows a spectrum having an excitation wavelength of 532 ηη, and Fig. 3b shows a spectrum with an excitation wavelength of 633 nm. It can be seen from Figures 3a and 3b that the Raman spectral region (shown as M in the corresponding) of the metallic single-walled carbon nanotubes has almost no RBM peak of a single straight-walled carbon nanotube, indicating the metal in the sample. The content of single-walled carbon nanotubes is extremely low, and the semi-conductive body of the single-walled carbon nanotubes (shown as S in the figure) is more than 90%. . Example 2 Positioning Growth of Semiconducting Single-walled Carbon Nanotubes

A semiconducting single-walled carbon nanotube was prepared in the same manner as in Example 1 except that: Ce(N0 ₃ ) ₃ and Fe(N03). were prepared at a concentration of 3:1 (0.3 mM: O.lmM) of ethanol. Mix the solution, use a micro-injector to draw 5 μL of the mixed solution onto the PDMS stamp with convex stripes on the surface, and after stamping it, imprint the stamp on the surface of the Si0 ₂ /Si substrate and then in the air at 200°. C was heated for 15 minutes to obtain a catalyst precursor stripe of Ce0 ₂ powder.

The optical micrograph of the obtained CeO ₂ powder loaded with the supported catalyst precursor Fe(N0 ₃ ) ₃ is similar to that of FIG.

The SEM photograph of the obtained carbon nanotubes is similar to that of Fig. 2.

The Raman spectrum of the obtained carbon nanotubes is similar to that of Figs. 3a and 3b. Example 3 Positioning Growth of Semiconducting Single-walled Carbon Nanotubes

A semiconducting single-walled carbon nanotube was prepared in a manner similar to that of Example 1, except that:

40 μL of ImM CuC ethanol solution was dropped on a silicon wafer and dried naturally in the air. The silicon wafer imprinted with pure CeO and the carrier powder stripes was placed on a chip and placed in a quartz tube (inner diameter 2.5 cm).

A SEM photograph of the obtained carbon nanotubes is shown in Fig. 4 . As can be seen from Fig. 4, single-walled carbon nanotubes were grown in a region where the growth substrate was imprinted with Ce0 ₂ 0 to achieve localized growth.

The Raman spectrum of the obtained carbon nanotubes is shown in Figs. 5a and 5b, wherein Fig. 5a shows that the excitation wavelength is

The spectrum of 532 nm, Figure 5b shows the spectrum of the excitation wavelength of 633 nm. As a result, similarly to Example 1, the selectivity of the semiconducting single-walled carbon nanotubes was over 90%. Example 4 Positioning Growth of Single-walled Carbon Nanotubes

A mixed solution of TEOS (ethyl silicate) and Fe(N0 ₃ ) _{3 in} a concentration ratio of 3:1 (0.3 mM : O. l mM ), using a micro-injector to draw 5 μL of the mixed solution onto the surface a protruding stripes PDMS stamp, let it dry in the seal imprinted upon said Si 0 ₂ / Si substrate surface, and then 500 ° C in air for heating the catalyst precursor stripes 15 minutes to obtain a Si0 ₂ powder load.

An optical micrograph of the obtained SiO ₂ powder to which the supported catalyst precursor was placed is shown in Fig. 6. As can be seen from Fig. 6, the Si0 book ₂ powder supporting the catalyst precursor is preferably arranged on the surface of the S i 0 ₂ /Si substrate in accordance with the stamp pattern, and the positioning on the surface of the substrate to the micron level is achieved.

A SEM photograph of the obtained carbon nanotubes is shown in FIG. As can be seen from Fig. 7, single-walled carbon nanotubes were grown in a region where the growth substrate was imprinted with SiO ₂ to achieve localized growth.

The Raman spectrum of the obtained carbon nanotube is shown in Figs. 8a and 8b, wherein Fig. 8a shows that the excitation wavelength is

The spectrum of 532 nm, Figure 8b shows the spectrum of the excitation wavelength of 633 nm. Different from Example 1 and Example 2, it can be seen that a certain proportion of RBM peaks of metallic single-walled carbon nanotubes appear, indicating that single-walled carbon nanotubes are obtained when S i 0 _{2 is} used as a catalyst carrier. The sample does not have semiconducting selectivity. Example 5 Random growth of semiconducting single-walled carbon nanotubes

A semiconducting single-walled carbon nanotube was prepared in the same manner as in Example 1, except that: the Ce0 ₂ powder loaded with the catalyst precursor Fe(N0 ₃ ) ₃ was weighed, 2 ml of ethanol was added, and Si was used to prepare a catalyst solution. l L Fe/Ce0 ₂ ethanol solution was dropped on the Si0 ₂ /Si substrate.

A SEM photograph of the obtained carbon nanotubes is shown in Fig. 9. As can be seen from Fig. 9, the catalyst-laden CeO ₂ powder was randomly distributed on the surface of the growth substrate, and a large number of random single-walled carbon nanotubes having no positioning growth properties were grown.

The Raman spectra of the obtained carbon nanotubes are shown in Figs. 10a and 10b, wherein Fig. 10a shows a spectrum having an excitation wavelength of 532 nm, and Fig. 1 Ob shows a spectrum having an excitation wavelength of 633 nm. As a result, similarly to Example 1, the selectivity of the semiconducting single-walled carbon nanotubes was over 90%. Comparative Example 1 Random growth of non-conductive selective single-walled carbon nanotubes

A semiconducting single-walled carbon nanotube was prepared in the same manner as in Example 1, except that: 0.5 mM FeCl ₃ .6H ₂ 0 catalyst precursor ethanol solution was prepared, and about ly L FeCl _r 6H ₂ 0 ethanol solution was dropped on Si0 ₂ /Si substrate.

An SEM photograph of the obtained carbon nanotubes is shown in Fig. 11. As can be seen from Fig. 1, the catalyst is randomly distributed on the surface of the growth substrate, and a large number of random single-walled carbon nanotubes having no positioning growth properties are grown.

The Raman spectrum of the obtained carbon nanotubes is shown in Figs. 12a and 12b, wherein Fig. 12a shows a spectrum having an excitation wavelength of 532 nm, and Fig. 12b shows a spectrum with an excitation wavelength of 633 nm. Similar to Example 3, it can be seen that a certain proportion of metallic single-walled carbon nanotubes have an RB M peak, indicating the obtained single-wall carbon Description

Nanotube samples do not have semiconducting selectivity. Experimental example

Raman light

For Raman spectroscopy, the incident laser energy at 532 nm is 2.33 eV. According to the kataura diagram, if the detected RBM peak is between 100-Ocm or 206-275 cm, it can be considered as metallic single-walled carbon nanotubes. The RBM peak position is between ΠΟ^Οόεπ ¹ and can be considered as a semiconducting single-walled carbon nanotube; the incident laser energy at 633 nm is 1.96 eV. According to the kataura diagram, if the detected RBM peak is 180-220 cm "Between ¹ , it can be considered as a metallic single-walled carbon nanotube. If the detected RBM peak is between 100-180 cm-' or 220-280 cm" ¹ , it can be considered as a semi-conducting single-wall carbon. nanotube.

The invention has been described in detail with reference to the preferred embodiments and exemplary embodiments, which are not to be construed as limiting. It will be apparent to those skilled in the art that various equivalents, modifications, and improvements may be made in the present invention without departing from the spirit and scope of the invention. The scope of the invention is defined by the appended claims.

All documents mentioned herein are hereby incorporated by reference in their entirety.

Claims

Claim

A method for positioning growth of single-walled carbon nanotubes, the method comprising the steps of:

(1) Providing an oxide carrier having a positioning property: providing a metal oxide or a non-metal oxide powder having a particle diameter of 1 nm - ΙΟΟΟμ ηι selected from Ce0 ₂ , A1 ₂ 0 ₃ , MgO, V ₂ _{_{_{0 5, Mn0 2, Cr 2}}} 0 3, Zr0 2, Hf0 2, Sn0 2, Pb0 2, La 2 0 3, Y 2 0 3, praseodymium oxide (Pr, 0,), Eu 2 0 3, Gd 2 0 ₃ and uranium oxide (U _x O, ), the non-metal oxide is Si0 ₂ ;

(2) Loading of the catalyst (precursor): Dispersing the oxide carrier having the positioning property obtained in the step (1) with the catalyst nanoparticle or the catalyst precursor in a solvent, sonicating, discarding the upper layer, separating and drying, and obtaining a catalyst (precursor) powder supported by an oxide carrier;

(3) Application of an oxide carrier loaded with a catalyst (precursor): an oxide carrier loaded with a catalyst (precursor) is subjected to photolithography, sputtering, evaporation, microcontact printing, nanoimprinting or embossing Etching or the like is applied to the growth substrate;

2. A method for positioning growth of single-walled carbon nanotubes, the method comprising the steps of:

(1) Providing an oxide carrier having a positioning property: providing a metal oxide or a non-metal oxide powder having a particle diameter of 1 nm - ΙΟΟΟμ ηι selected from Ce0 ₂ , A1 ₂ 0 ₃ , MgO, V ₂ _{_{_{0 5, Mn0 2, Cr 2}}} 0 3, Zr0 2, Hf0 2, Sn0 2, Pb0 2, La 2 0 3, Y 2 0 3, praseodymium oxide _{_{(Pr x O y), Eu}} 2 0 3, Gd 2 0 ₃ and uranium oxide (U\0,.), the non-metal oxide is Si0 ₂ ;

(2) the deposition of the oxide carrier: - the above oxide carrier is deposited on the growth substrate by photolithography, sputtering, evaporation, microcontact printing, nanoimprinting or squeegee etching;

(3) deposition of a catalyst: on the growth substrate obtained in the above step (2), depositing a catalyst on the oxide carrier in the growth substrate by vapor-depositing metal catalyst particles or the like;

(4) CVD growth of single-walled carbon nanotubes: the growth substrate obtained in the step (3) is subjected to a carbon source gas at a flow rate of 10 to 1000 ml/min, optionally with hydrogen gas passing through the chemical vapor phase. Deposition, growth of single-walled carbon nanotubes.

A method for positioning growth of a semiconducting single-walled carbon nanotube, the method comprising the steps of: (1) providing an oxide carrier having a positioning property: providing a metal oxide having a particle diameter of 1 nm - ΙΟΟΟμ ηι, the metal oxide is selected from _{_{_{Ce0 2, V 2 0 5,}}} Mn0 2, Cr 2 0 3, Zr0 2, Hf0 2, Sn0 2, Pb0 2, La 2 0 3, Y 2 0 3, praseodymium oxide (Pr _x O _v) , Eu ₂ 0 ₃ , Gd ₂ 0 ₃ and uranium oxide (U, 0\ );

(2) Loading of the catalyst (precursor): Dispersing the oxide carrier having the positioning property obtained in the step (1) with the catalyst nanoparticle or the catalyst precursor in a solvent, sonicating, discarding the upper layer, and separating the dried Obtaining a catalyst (precursor) powder supported by an oxide carrier;

(3) Application of oxide carrier supported with catalyst (precursor): Oxidation, sputtering, evaporation, microcontact printing, nanoimprinting or squeegee Etching or the like is applied to the growth substrate;

A method for positioning growth of a semiconducting single-walled carbon nanotube, the method comprising the steps of: (1) providing an oxide carrier having a positioning property: providing a metal oxide having a particle diameter of from 1 nm to 1000 μm, metal oxide is selected _{_{_{Ce0 2, V 2 0 5,}}} Mn0 2> Cr 2 0 3, Zr0 2, Hf0 2, Sn0 2, Pb0 2, La 2 0 3, Y 2 0 3, praseodymium oxide (Pr _x O _y ), Eu ₂ 0 ₃ , Gd ₂ 0 ₃ and uranium oxide (U _x O,):

(2) The placement of the oxide carrier: the above oxide carrier is deposited on the growth substrate by photolithography, sputtering, evaporation, microcontact printing, nanoimprinting or squeegee etching; Claim

5. Method according to claim 1 or 3, wherein the combination of steps (1) and (2) is replaced by:

For the non-metal oxide having the locating property, a mixed solution containing the ester of the non-metal silicon and the catalyst precursor is provided. -

A method for preparing a semiconducting single-walled carbon nanotube, the method comprising the steps of: (1) cleaning a quartz, a silicon wafer or a ceramic substrate;

(2) Preparation of oxide carrier: hydrolysis reaction of soluble nitrate with sodium hydroxide of metal Ce, V, Mn, Cr, Zr, Hf, Sn, Pb, La, Y, Pr, Eu and Gd, using water prepared as follows hot synthesis of metal _{_{_{oxide: Ce0 2, V 2 0 5}}} , Mn0 2, Cr 2 0 3, Zr0 2, Hf0 2, Sn0 2, Pb0 2, La 2 0 3, Y 2 0 3, praseodymium oxide (Pr _x O _y ). Eu ₂ 0 ₃ and Gd ₂ 0 ₃ , the product is washed by water and centrifuged for use; ^_

(3) Loading of the catalyst: Dispersing the oxide carrier obtained in the step (2) with the catalyst nanoparticles or the catalyst precursor in a solvent, sonicating, discarding the upper layer, and separating and drying to obtain a catalyst supported by the oxide carrier ( Precursor) powder;

(4) Preparation of a catalyst (precursor) solution supported by an oxide carrier: Dispersing a catalyst (precursor) powder supported by an oxide carrier obtained in the step (3) in a solvent to obtain an oxide carrier-supported powder Catalyst (precursor) solution;

(5) CVD growth of semiconductor-selective single-walled carbon nanotubes: The oxide carrier-supported catalyst (precursor) powder prepared in step (3) is placed in a ceramic or quartz boat or disk-shaped base container. Or, the catalyst (precursor) solution supported by the oxide carrier obtained in the step (4) is dropwise added to the silicon wafer, the quartz, and the ceramic substrate, and pre-reduced by optionally introducing hydrogen gas at a temperature of 600-1500 Torr. The single-walled carbon nanotubes are then grown by chemical vapor deposition (CVD) with a carbon source gas at a flow rate of 10-1000 ml/min, optionally with the introduction of hydrogen.

The method according to any one of claims 1 to 6, wherein the soluble Ce ³⁺ salt solution is mixed with a soluble inorganic base solution, reacted at a temperature of 25 to 24 CTC, and separated and dried to obtain a Ce0 ₂ carrier.

The method according to any one of claims 1 to 6, wherein the catalyst precursor is selected from the group consisting of soluble salts of iron, copper, lead, nickel, cobalt, manganese, chromium and molybdenum.

The method according to any one of claims 1 to 6, wherein the metal oxide is

Ce0 ₂ .