Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS20040105807 A1
Publication typeApplication
Application numberUS 10/410,069
Publication dateJun 3, 2004
Filing dateApr 8, 2003
Priority dateNov 29, 2002
Also published asCN1290763C, CN1504407A
Publication number10410069, 410069, US 2004/0105807 A1, US 2004/105807 A1, US 20040105807 A1, US 20040105807A1, US 2004105807 A1, US 2004105807A1, US-A1-20040105807, US-A1-2004105807, US2004/0105807A1, US2004/105807A1, US20040105807 A1, US20040105807A1, US2004105807 A1, US2004105807A1
InventorsShoushan Fan, Liang Liu, KaiLi Jiang
Original AssigneeShoushan Fan, Liang Liu, Jiang Kaili
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method for manufacturing carbon nanotubes
US 20040105807 A1
Abstract
The present invention provides a method for manufacturing carbon nanotubes. The method includes the following steps: (a) providing a substrate (3); (b) depositing a catalyst material (1) onto the substrate; (c) exposing the catalyst material to a carbon containing gas for a predetermined period of time in a predetermined temperature such that an array of carbon nanotube having a predetermined length grows from the substrate in a direction substantially perpendicular to the substrate; (d) removing the carbon nanotubes from the substrate; and (e) dispersing the carbon nanotubes via ultrasonication in a dispersant, the dispersant being ethanol or 1-2 dichloroethane. The carbon nanotubes of the present invention have a predetermined same length and are aligned parallel to each other.
Images(4)
Previous page
Next page
Claims(14)
What is claimed is:
1. A method for manufacturing carbon nanotubes comprising steps as follows:
(1) providing a substrate;
(2) depositing a catalyst material onto the substrate;
(3) exposing the catalyst material to a carbon containing gas for a predetermined period of time at a predetermined temperature such that an array of carbon nanotubes having a predetermined length grows from the substrate in a direction substantially perpendicular to the substrate; and
(4) removing the carbon nanotubes from the substrate.
2. The method in accordance with claim 1, further comprising dispersing the carbon nanotubes via ultrasonication in a dispersant after step (4).
3. The method in accordance with claim 1, wherein in step (1) the catalyst material is selected from the group consisting of iron, cobalt and nickel.
4. The method in accordance with claim 3, wherein step (2) comprises depositing a catalyst material film between 4 and 10 nm thickness on the substrate and annealing the catalyst material film at between 300-500 degrees Centigrade for between 8-12 hours such that the catalyst material is changed into separate nanoparticles.
5. The method in accordance with claim 1, wherein in step (3) the predetermined temperature is between 600-1000 degrees Centigrade.
6. The method in accordance with claim 5, wherein in step (3) the carbon containing gas is selected from the group consisting of ethylene, methane and acetylene.
7. The method in accordance with claim 5, wherein step (3) further comprises flowing protecting gas before exposing the catalyst material to the carbon containing gas.
8. The method in accordance with claim 1, wherein step (3) comprises exposing the catalyst material iron to ethylene at 690 degrees Centigrade for 15 seconds such that a carbon nanotubes array of 10 micron height grows from the substrate in a direction substantially perpendicular to the substrate.
9. The method in accordance with claim 1, wherein step (3) comprises exposing the catalyst material iron to ethylene at 690 degrees Centigrade for 5 minutes such that a carbon nanotubes array of 100 micron height grows from the substrate in a direction substantially perpendicular to the substrate.
10. The method in accordance with claim 1, wherein step (3) comprises exposing the catalyst material iron to ethylene at 710 degrees Centigrade for 10 minutes such that a carbon nanotubes array of 500 micron height grows from the substrate in a direction substantially perpendicular to the substrate.
11. The method in accordance with claim 1, wherein in step (4) the carbon nanotubes are removed from the substrate by using a blade.
12. The method in accordance with claim 2, wherein the dispersant is select from ethanol or 1-2 dichloroethane.
13. A method for manufacturing carbon nanotubes comprising steps as follows:
(1) providing a plurality of substrates in a furnace;
(2) depositing a catalyst material onto each of the substrates;
(3) exposing the catalyst material to a carbon containing gas for a predetermined period of time at a predetermined temperature such that an array of carbon nanotubes having a predetermined length grows from the substrate in a direction substantially perpendicular to the substrate; and
(4) removing the carbon nanotubes from the substrate.
14. The method in accordance with claim 13, wherein said substrates are upwardly obliquely arranged along a lengthwise direction of the furnace and in a parallel relation with one another, and commonly facing toward an entrance of the furnace where the gas comes in.
Description
BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a method for manufacturing carbon nanotubes, and more particularly to a method for manufacturing carbon nanotubes having a predetermined same length.

[0003] 2. Description of Related Art

[0004] Carbon nanotubes have shown many unique electrical and mechanical properties. Their potential applications include use in field emitters, gas storage and separation, nanoprobes, chemical sensors and high strength composites. Currently there are three principal techniques to manufacture high quality carbon nanotubes, namely arc discharge, laser ablation and chemical vapor deposition. The carbon nanotubes made by arc discharge and laser ablation are often accompanied by a large volume (up to 50%) of contaminants and are tangled with each other. It is very difficult to separate the carbon nanotubes. Furthermore, those production techniques are capital-intensive and are likely limited to research quantities. The carbon nanotubes made using a chemical vapor deposition technique are in good yield—occasionally over 90%—and have few contaminants.

[0005] Carbon nanotubes having a predetermined same length and being parallel to each other are generally desired in field emission devices, in composite reinforced material and in electrovacuum device. However, not all methods can directly produce carbon nanotubes having a predetermined same length and being parallel to each other.

[0006] Therefore, a method for manufacturing carbon nanotubes having a predetermined same length and being parallel to each other is desired.

SUMMARY OF THE INVENTION

[0007] Accordingly, an object of the present invention is to provide a method for manufacturing carbon nanotubes that have a predetermined same length and that are aligned parallel to each other.

[0008] In order to achieve the object set forth above, the present invention provides a method for manufacturing carbon nanotubes. The method comprises the follows steps:

[0009] (1) depositing a catalyst material onto a substrate;

[0010] (2) exposing the catalyst material to a carbon containing gas for a predetermined period of time at a predetermined temperature such that an array of carbon nanotubes having a predetermined length grows from the substrate in a direction substantially perpendicular to the substrate; and

[0011] (3) removing the carbon nanotubes from the substrate.

[0012] Other objects, advantages and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a schematic view of depositing a catalyst material onto a substrate in accordance with the present invention;

[0014]FIG. 2 is a schematic view of an annealed catalyst material on a substrate in accordance with the present invention;

[0015]FIG. 3 is a schematic view of growing an array of carbon nanotube on a plurality of substrates in accordance with the present invention;

[0016]FIG. 4 is a schematic view of removing the carbon nanotubes from one of the substrates of FIG. 3 in accordance with the present invention;

[0017]FIG. 5 is a transmission electron microscope image of an array of carbon nanotubes in accordance with the present invention after treatment by ultrasonitication in a dispersant;

[0018]FIG. 6 is a transmission electron microscope image of the array of carbon nanotubes in accordance with the present invention after treatment by ultrasonication in a dispersant, wherein the carbon nanotubes of the array are separated; and

[0019]FIGS. 7, 8, 9 and 10 are respectively arrays of carbon nanotube having different lengths in accordance with the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

[0020] The present invention provides a method for manufacturing carbon nanotubes that have a predetermined same length and that are aligned parallel to each other. The method comprises steps as follows:

[0021] (1) referring to FIG. 1, providing a substrate 3 comprising a wafer silicon or silica;

[0022] (2) depositing a catalyst material 1 onto a surface of the substrate 3 by electron beam evaporation, sputtering or coating, such that a catalyst material film 11 between 4-10 nm thick is formed on the surface of the substrate 3, the catalyst material 1 being selected from the group consisting of iron, nickel and cobalt;

[0023] (3) referring to FIG. 2, annealing the catalyst material film 11 in air at 300-500 degrees Centigrade for between 8-12 hours, such that the catalyst material film 11 is changed into separate nanoparticles 12;

[0024] (4) referring to FIG. 3, putting a plurality of the substrates 3 with nanoparticles 12 in a furnace 4;

[0025] (5) heating the furnace 4 to between 600-1000 degrees Centigrade in flowing protecting gas (not labeled), the protecting gas being selected from the group consisting of argon, nitrogen and helium;

[0026] (6) introducing a flow of carbon containing gas into the furnace 4 for between 15 seconds and 40 minutes, the carbon containing gas being selected from the group consisting of acetylene, methane and ethylene;

[0027] (7) growing an array of carbon nanotubes 5 (see FIG. 4) having a predetermined length from the surface of each substrate 3;

[0028] (8) cooling the furnace 4 to room temperature, and taking the substrates 3 out from the furnace 4;

[0029] (9) referring to FIG. 4, removing the carbon nanotubes 5 from the array of each substrate 3 by using a blade 6; and

[0030] (10) dispersing the carbon nanotubes 5 via ultrasonication in a dispersant, the dispersant being ethanol or 1-2 dichloroethane.

[0031] Referring to FIGS. 5 and 6, since the carbon nanotubes 5 of the array are substantially parallel to each other, a multiplicity of separate carbon nanotubes 5 can be easily obtained after ultrasonication in the dispersant.

[0032] Referring to FIGS. 7, 8, 9, and 10, the predetermined length of the carbon nanotubes 5 can be obtained by controlling reaction conditions such as a time of reaction and a temperature of reaction.

EXAMPLE 1

[0033] growing a carbon nanotube array of 10 microns height on each of a plurality of silicon wafers. An iron film of 5 nm thickness is deposited on a porous surface of each silicon wafer. The porous surfaces of the silicon wafers are obtained by electrochemical etching of P-doped N+-type silicon wafers. The silicon wafers are then annealed in air at 400 degrees Centigrade for 10 hours. This annealing step oxidizes the iron film to create a largely iron oxide nanoparticles. The silicon wafers are then placed in a cylindrical quartz boat sealed at one end, and the quartz boat is put into the center of a 2-inch quartz tube reactor housed in a tube furnace. The furnace is heated to 690 degrees Centigrade in flowing argon. Ethylene is then introduced into the furnace for 15 seconds, after which the furnace is cooled to room temperature.

EXAMPLE 2

[0034] growing a carbon nanotube array of 100 microns height on each of a plurality of silicon wafers. An iron film of 5 nm thickness is deposited on a porous surface of each silicon wafer, similar to that described above in relation to Example 1. The substrates are then annealed in air at 400 degrees Centigrade for 10 hours. The substrates are placed in a cylindrical quartz boat sealed at one end, and the quartz boat is put into the center of a 2-inch quartz tube reactor housed in a tube furnace. The furnace is heated to 690 degrees Centigrade in flowing argon. Ethylene is then introduced into the furnace for 5 minutes, after which the furnace is cooled to room temperature.

EXAMPLE 3

[0035] growing a carbon nanotube array of 500 microns height on each of a plurality of silicon wafers. An iron film of 5 nm thickness is deposited on a porous surface of each silicon wafer, similar to that described above in relation to Example 1. The substrates are then annealed in air at 400 degrees Centigrade for 10 hours. The substrates are placed in a cylindrical quartz boat sealed at one end, and the quartz boat is put into the center of a 2-inch quartz tube reactor housed in a tube furnace. The furnace is heated to 710 degrees Centigrade in flowing argon. Ethylene is then introduced into the furnace for 10 minutes, after which the furnace is cooled to room temperature.

[0036] It is understood that the invention may be embodied in other forms without departing from the spirit thereof. Thus, the present examples and embodiments are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US7302829 *Dec 1, 2003Dec 4, 2007General Electric CompanyContactless humidity/chemical vapor sensor device and associated method of fabrication
US7682658 *Mar 8, 2006Mar 23, 2010Tsinghua UniversityIn a quartz boat, positioning a second catalyst adjacent to a substrate having a film of first catalyst; directing acetylene and argon carrier toward the second catalyst to the substrate to produce a carbonaeous product for promoting catalytic activity of the first catalyst to grow the tubes
US7687109Mar 8, 2006Mar 30, 2010Tsinghua UniversityApparatus and method for making carbon nanotube array
US7700048Mar 8, 2006Apr 20, 2010Tsinghua UniversityApparatus for making carbon nanotube array
US7713589Mar 8, 2006May 11, 2010Tsinghua UniversityMethod for making carbon nanotube array
US7731930Nov 10, 2005Jun 8, 2010Nikon Corporationa proportion of double-walled carbon nanotubes to carbon nanotubes contained in the assembly is 70% or more; field emission display; physical properties
US7811149 *Jul 21, 2006Oct 12, 2010Tsinghua UniversityMethod for fabricating carbon nanotube-based field emission device
US7872407Dec 14, 2007Jan 18, 2011Tsinghua UniversityField emission cathode having successive and oriented carbon nanotube bundles
US8048256Dec 14, 2007Nov 1, 2011Tsinghua UniversityCarbon nanotube film structure and method for fabricating the same
US8236389Nov 6, 2008Aug 7, 2012Tsinghua UniversityMethod for making carbon nanotube films
US8337979Aug 24, 2007Dec 25, 2012Massachusetts Institute Of TechnologyNanostructure-reinforced composite articles and methods
US8533945Mar 31, 2008Sep 17, 2013Fujitsu Semiconductor LimitedWiring structure and method of forming the same
US8591988Oct 16, 2012Nov 26, 2013Babcock & Wilcox Technical Services Y-12, LlcMethod of fabrication of anchored nanostructure materials
US8609189Sep 28, 2011Dec 17, 2013King Abdulaziz UniversityMethod of forming carbon nanotubes from carbon-rich fly ash
US8734996Dec 14, 2007May 27, 2014Tsinghua UniversityAnode of lithium battery and method for fabricating the same
EP2441729A1 *May 18, 2007Apr 18, 2012Massachusetts Institute Of TechnologyMethod of forming a composite article
WO2007117503A2 *Apr 5, 2007Oct 18, 2007Limin HuangPreparing nanoparticles and carbon nanotubes
WO2011053459A1 *Oct 13, 2010May 5, 2011Applied Nanostructured Solutions, Llc.Cnt-infused metal fiber materials and process therefor
WO2011054008A2 *Nov 2, 2010May 5, 2011Applied Nanostructured Solutions, LlcCnt-infused aramid fiber materials and process therefor
WO2012019309A1 *Aug 12, 2011Feb 16, 2012The Governors Of The University Of AlbertaMethod of fabricating a carbon nanotube array
WO2014011755A1 *Jul 10, 2013Jan 16, 2014Carbice Nanotechnologies, Inc.Vertically aligned arrays of carbon nanotubes formed on multilayer substrates
Classifications
U.S. Classification423/447.3
International ClassificationD01F9/127, C01B31/02
Cooperative ClassificationB82Y40/00, D01F9/127, C01B31/0226, D01F9/1275, C01B2202/08, B82Y30/00, C01B31/0273, D01F9/1271, C01B2202/34, D01F9/1272
European ClassificationB82Y30/00, C01B31/02B4B, C01B31/02B4D6, B82Y40/00, D01F9/127, D01F9/127D4, D01F9/127B, D01F9/127B2
Legal Events
DateCodeEventDescription
Apr 8, 2003ASAssignment
Owner name: HON HAI PRECISION IND. CO., LTD., TAIWAN
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:FAN, SHOUSHAN;LIU, LIANG;JIANG, KAILI;REEL/FRAME:013959/0284
Effective date: 20030403
Owner name: TSINGHAU UNIVERSITY, SWITZERLAND