U.S. patent application number 10/632472 was filed with the patent office on 2005-04-07 for selective area growth carbon nanotubes by metal imprint method.
This patent application is currently assigned to National Chiao Tung University. Invention is credited to Chao, Chi Wei, Hou, Chih Yuan, Wu, YewChung Sermon.
Application Number | 20050074393 10/632472 |
Document ID | / |
Family ID | 34059063 |
Filed Date | 2005-04-07 |
United States Patent
Application |
20050074393 |
Kind Code |
A1 |
Wu, YewChung Sermon ; et
al. |
April 7, 2005 |
Selective area growth carbon nanotubes by metal imprint method
Abstract
Manufacturing methods of using a metal imprint technique for
growing carbon nanotubes on selective areas and the structures
formed thereof are provided. One of the manufacturing methods
includes steps of forming a first substrate with tapered structures
applied with a metal catalyst, imprinting a second substrate on the
first substrate for being a growth substrate, and growing carbon
nanotubes on the growth substrate. The other manufacturing method
includes steps of forming a first substrate with tapered
structures, imprinting the first substrate on a second substrate
applied with a metal catalyst for forming a second growth
substrate, and growing carbon nanotubes on the second grown
substrate. And, the formed structures of the present invention
include a substrate, plural carbon nanotubes, and plural imprinted
vestiges.
Inventors: |
Wu, YewChung Sermon;
(Taichung, TW) ; Chao, Chi Wei; (Taipei, TW)
; Hou, Chih Yuan; (Chiai, TW) |
Correspondence
Address: |
SILICON VALLEY PATENT GROUP LLP
2350 MISSION COLLEGE BOULEVARD
SUITE 360
SANTA CLARA
CA
95054
US
|
Assignee: |
National Chiao Tung
University
Hsinchu
TW
|
Family ID: |
34059063 |
Appl. No.: |
10/632472 |
Filed: |
August 1, 2003 |
Current U.S.
Class: |
423/447.3 ;
428/398; 428/408 |
Current CPC
Class: |
Y10S 977/742 20130101;
Y10S 977/842 20130101; Y10T 428/30 20150115; Y10S 977/888 20130101;
Y10T 428/2975 20150115; D01F 9/12 20130101; B82Y 30/00
20130101 |
Class at
Publication: |
423/447.3 ;
428/408; 428/398 |
International
Class: |
D01F 009/12; B32B
009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 6, 2003 |
TW |
092104868 |
Claims
What is claimed is:
1. A method for growing a plurality of carbon nanotubes on a
selective area, comprising steps of: a) forming a first masking
layer on a first substrate; b) photolithographing said first
masking layer for forming a plurality of specific areas on said
first substrate; c) etching said plurality of specific areas for
forming a second masking layer on said first substrate; d) etching
said second masking layer and said first substrate for forming a
plurality of tapered structures; e) applying a catalyst on said
plurality of tapered structures; f) imprinting a second substrate
on said first substrate having said catalyst thereon for being a
growth substrate with a plurality of vestiges of said catalyst; and
g) growing said plurality of carbon nanotubes on said growth
substrate.
2. The method as claimed in claim 1, wherein both said first
substrate and said second substrate are silicon substrates.
3. The method as claimed in claim 1, wherein said first masking
layer is a first silicon oxide masking layer formed at a
temperature ranged from 800 to 1200.degree. C. and has a thickness
ranged from 2000 to 7000 .ANG..
4. The method as claimed in claim 1, wherein said step c) is
performed by a BOE (Buffer Oxide Etching) solution containing a
hydrofluoric acid.
5. The method as claimed in claim 1, wherein said step d) is
performed by a chemical solution containing a potassium
hydroxide.
6. The method as claimed in claim 1, wherein said step e) is
performed by a physical deposition method.
7. The method as claimed in claim 1, wherein said second masking
layer is formed just on said plurality of specific areas.
8. The method as claimed in claim 1, wherein said plurality of
tapered structures are a plurality of sharp silicon structures.
9. The method as claimed in claim 1, wherein said step b) further
comprises steps of: b1) providing a mask; b2) forming a first
photoresist layer on said first masking layer; and b3) etching said
first photoresist layer with said mask for forming a second
photoresist layer.
10. The method as claimed in claim 9, wherein said second masking
layer comprises said second photoresist layer and a second silicon
oxide masking layer.
11. The method as claimed in claim 10, wherein said step c) further
comprises a step of c1) removing said second photoresist layer by
an acetone.
12. The method as claimed in claim 1, wherein said catalyst is a
metal catalyst selected from a group consisting of a ferrum, a
cobalt, and a nickel.
13. The method as claimed in claim 1, wherein each of said
plurality of vestiges of said catalyst has a diameter ranged from
10 to 200 nanometers.
14. The method as claimed in claim 13, wherein each of said
plurality of vestiges of said catalyst introduces a growth of each
of said carbon nanotubes.
15. A method for growing a plurality of carbon nanotubes on a
selective area, comprising steps of: a) forming a first masking
layer on a first substrate; b) photolithographing said first
masking layer for forming a plurality of specific areas on said
first substrate; c) etching said plurality of specific areas for
forming a second masking layer on said first substrate; d) etching
said second masking layer and said first substrate for forming a
plurality of tapered structures on said first substrate; e)
applying a catalyst on a second substrate; f) imprinting said first
substrate on said second substrate for respectively obtaining a
residuum on a tip of each of said plurality of tapered structures;
and g) respectively growing each of said carbon nanotubes on each
of said plurality of tapered structures having said residuum.
16. The method as claimed in claim 15, wherein said catalyst is a
metal catalyst selected from a group consisting of a ferrum, a
cobalt, and a nickel.
17. The method as claimed in claim 15, wherein said step b) further
comprises steps of: b1) providing a mask; b2) forming a first
photoresist layer on said first masking layer; and b3) etching said
first photoresist layer with said mask for forming a second
photoresist layer.
18. A method for growing a plurality of carbon nanotubes,
comprising steps of: a) providing a first substrate having a
plurality of tapered structures; b) applying a catalyst on said
plurality of tapered structures; c) imprinting a second substrate
on said first substrate for obtaining a plurality of vestiges of
said catalyst on said second substrate; and d) growing said
plurality of carbon nanotubes on said plurality of vestiges.
19. The method as claimed in claim 18, wherein said catalyst is a
metal catalyst selected from a group consisting of a ferrum, a
cobalt, and a nickel.
20. A carbon nanotube structure, comprising: a silicon substrate;
at least an imprinted vestige deposited on said silicon substrate;
and at least a carbon nanotube grown on said imprinted vestige.
21. The structure as claimed in claim 20, wherein said imprinted
vestige is formed by a metal imprint technique.
22. A carbon nanotube structure, comprising: a silicon substrate
with a plurality of tapered structures; and a plurality of carbon
nanotubes respectively grown on a tip of each of said plurality of
tapered structures.
23. The structure as claimed in claim 22, wherein said plurality of
carbon nanotubes are grown along a same direction.
24. The structure as claimed in claim 22, wherein said plurality of
tapered structures are formed by steps of a photolithography, a
first etching, and a second etching.
25. The structure as claimed in claim 22, wherein said plurality of
carbon nanotubes are introduced to grow by a metal catalyst.
Description
FIELD OF THE INVENTION
[0001] This invention relates to a method for growing carbon
nanotubes on selective areas and the formed structures thereof, and
particularly to a method for growing carbon nanotubes on selective
areas by a metal imprint technique and the formed structures
thereof.
BACKGROUND OF THE INVENTION
[0002] A carbon nanotube (CNT) is a tubular material formed by
rolling up a graphite piece. The structure can be divided into two
forms, the single-walled type and the multi-walled type. Since the
carbon nanotube has been discovered, it is found having the
properties of high aspect ratio, small curvature radius at the
sharp structure, high tensile strength, great heat conductivity,
good super-conductivity at room temperature, and high chemical
stability. Furthermore, the conductivity of CNT can easily be
changed when CNT is made into nano-line or nano-semiconductor by
various rolling-up means. Therefore, CNT has become the most
popular research object for the scientists recently.
[0003] Nowadays, the methods for manufacturing carbon nanotubes
include the arc-discharge method, the laser ablation method, the
chemical vapor deposition method, and the organic metal pyrolysis
method. The carbon nanotubes made by the respective method
described above are all different. For example, the carbon nanotube
can either be formed with a diameter ranged from one to hundreds of
nanometers or be formed with a length ranged from hundreds of
nanometers to hundreds of millimeters. Due to the carbon nanotube
has the properties of compact volume, high strength, great heat
conductivity and nigh electricity conductivity, and low
power-consuming, it has been thought as the superior materials for
developing various application products at the nanometer-level. For
instance, the carbon nanotube can be used for manufacturing a
transistor. In which, the carbon nanotube can be used as the
electric current channel and the intensity of the electricity
fields effecting on the carbon nanotube are changed by inputting
various gate voltages. Accordingly, the transistor can be turned on
or turned off simply by controlling the width of the current
channel. Furthermore, the carbon nanotubes can also be applied to
the manufacture of the field emission display and the probe for the
atomic force microscopy. The resolution of the atomic force
microscopy will be substantially improved by the probe made of the
carbon nanotubes.
[0004] In the conventional method of manufacturing a carbon
nanotube, it does not matter whether the finished products of
carbon nanotubes are two-dimension or three-dimension structures,
each carbon nanotube is usually a web structure with similar
diameter. During the manufacturing process, a few components are
including are necessarily provided in advance, including at least a
substrate, a metal powder, and a reagent gas containing a carbon.
Next, the reaction is performed under high temperature, and then
the carbon nanotubes are grown and formed from the plural concaves
on the substrate mentioned earily. In the conventional method, the
carbon nanotubes are usually grown without controlling their
directions and densities. However, the directions and densities of
the formed carbon nanotubes will affect the efficiency and the
prime cost of the relative products. The product made of carbon
nanotubes having one single direction will have a more complete
structure, a better heat conductivity and a better electricity
conductivity. Contrarily, the product made of carbon nanotubes
without one single direction will not reveal the properties of
great heat conductivity and high electricity conductivity as they
are supposed to reveal. Furthermore, if the density of the carbon
nanotubes is not high enough, the corresponding product will not
fully reveal the excellent properties of the carbon nanotubes, such
as great heat conductivity and high electricity conductivity, and
high tensile intensity. Oppositely, if the density of the carbon
nanotubes is too high, the corresponding high production costs will
be wasted meaninglessly.
[0005] As above-mentioned, a method for controlling the
manufactured carbon nanotubes on selective areas with a desired
growing direction and a desired density will have great utility in
the relevant industries.
[0006] Because of the technical defects described above, the
applicant keeps on carving unflaggingly to develop a "SELECTIVE
AREA GROWTH OF CARBON NANOTUBES BY METAL IMPRINT METHOD" through
wholehearted experience and research.
SUMMARY OF THE INVENTION
[0007] It is an object of the present invention to provide a method
for manufacturing carbon nanotubes on selective areas for
controlling the densities of the manufactured carbon nanotubes.
[0008] It is another object of the present invention to provide a
method for manufacturing carbon nanotubes having a desired
direction for improving the relevant heat and electricity
conductivities of the related products.
[0009] It is another object of the present invention to provide a
carbon nanotube structure having a more complete structure and a
higher tensile intensity.
[0010] In accordance with one aspect of the present invention, a
method for growing a plurality of carbon nanotubes on a selective
area is provided. The method includes steps of: step a) forming a
first masking layer on a first substrate, step b)
photolithographing the first masking layer for forming a plurality
of specific areas on the first substrate, step c) etching the
plurality of specific areas for forming a second masking layer on
the first substrate, step d) etching the second masking layer and
the first substrate for forming a plurality of tapered structures,
step e) applying a catalyst on the plurality of tapered structures,
step f) imprinting a second substrate on the first substrate having
the catalyst thereon for being a growth substrate with a plurality
of vestiges of the catalyst, and step g) growing the plurality of
carbon nanotubes on the growth substrate.
[0011] Preferably, both the first substrate and the second
substrate are silicon substrates.
[0012] Preferably, the first masking layer is a first silicon oxide
masking layer formed at a temperature ranged from 800 to
1200.degree. C. and has a thickness ranged from 2000 to 7000
.ANG..
[0013] Preferably, the step c) is performed by a BOE (Buffer Oxide
Etching) solution containing a hydrofluoric acid.
[0014] Preferably, the step d) is performed by a chemical solution
containing a potassium hydroxide.
[0015] Preferably, the step e) is performed by a physical
deposition method.
[0016] Preferably, the second masking layer is formed just on the
plurality of specific areas.
[0017] Preferably, the plurality of tapered structures are a
plurality of sharp silicon structures.
[0018] Preferably, the step b) further includes step 1) providing a
mask, step b2) forming a first photoresist layer on the first
masking layer, and step b3) etching the first photoresist layer
with the mask for forming a second photoresist layer.
[0019] Preferably, the second masking layer includes the second
photoresist layer and a second silicon oxide masking layer.
[0020] Preferably, the step c) further includes a step c1) removing
the second photoresist layer by an acetone.
[0021] Preferably, the catalyst is a metal catalyst selected from a
group consisting of a ferrum, a cobalt, and a nickel.
[0022] Preferably, each of the plurality of vestiges of the
catalyst has a diameter ranged from 10 to 200 nanometers.
[0023] Preferably, each of the plurality of vestiges of the
catalyst introduces a growth of each of the carbon nanotubes.
[0024] In accordance with another aspect of the present invention,
a method for growing a plurality of carbon nanotubes on a selective
area is provided. The method includes steps of: step a) forming a
first masking layer on a first substrate, step b)
photolithographing the first masking layer for forming a plurality
of specific areas on the first substrate, step c) etching the
plurality of specific areas for forming a second masking layer on
the first substrate, step d) etching the second masking layer and
the first substrate for forming a plurality of tapered structures
on the first substrate, step e) applying a catalyst on a second
substrate, step f) imprinting the first substrate on the second
substrate for respectively obtaining a residuum on a tip of each of
the plurality of tapered structures, and step g) respectively
growing each of the carbon nanotubes on each of the plurality of
tapered structures having the residuum.
[0025] Preferably, the catalyst is a metal catalyst selected from a
group consisting of a ferrum, a cobalt, and a nickel.
[0026] Preferably, the step b) further includes steps of step b1)
providing a mask, step b2) forming a first photoresist layer on the
first masking layer, and step b3) etching the first photoresist
layer with the mask for forming a second photoresist layer.
[0027] In accordance with another aspect. of the present invention,
a method for growing a plurality of carbon nanotubes is provided.
The method includes steps of: step a) providing a first substrate
having a plurality of tapered structures, step b) applying a
catalyst on the plurality of tapered structures, step c) imprinting
a second substrate on the first substrate for obtaining a plurality
of vestiges of the catalyst on the second substrate, and step d)
growing the plurality of carbon nanotubes on the plurality of
vestiges.
[0028] Preferably, the catalyst is a metal catalyst selected from a
group consisting of a ferrum, a cobalt, and a nickel.
[0029] In accordance with another aspect of the present invention,
a carbon nanotube structure is provided. The structure includes a
silicon substrate, at least an imprinted vestige deposited on the
silicon substrate, and at least a carbon nanotube grown on the
imprinted vestige.
[0030] Preferably, the imprinted vestige is formed by a metal
imprint technique.
[0031] In accordance with another aspect of the present invention,
a carbon nanotube structure is provided. The structure includes a
silicon substrate with a plurality of tapered structures, and a
plurality of carbon nanotubes respectively grown on a tip of each
of the plurality of tapered structures.
[0032] Preferably, the plurality of carbon nanotubes are grown
along a same direction.
[0033] Preferably, the plurality of tapered structures are formed
by steps of a photolithography, a first etching, and a second
etching.
[0034] Preferably, the plurality of carbon nanotubes are introduced
to grow by a metal catalyst.
[0035] The foregoing and other features and advantages of the
present invention will be clearly understood through the following
descriptions with reference to the drawings, wherein:
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] FIG. 1 is the schematic diagram illustrating the silicon
substrate coated with the silicon oxide masking layer thereon
according to a preferred embodiment of the present invention;
[0037] FIG. 2(a) is the schematic diagram illustrating the
photolithography process according to a preferred embodiment of the
present invention;
[0038] FIG. 2(b) is the schematic diagram illustrating the silicon
oxide masking layer having the covered photoresist layer formed
thereon according to a preferred embodiment of the present
invention;
[0039] FIG. 3 is the schematic diagram illustrating the silicon
substrate having the covered silicon oxide masking layer formed
thereon according to a preferred embodiment of the present
invention;
[0040] FIG. 4 is the schematic diagram illustrating the silicon
substrate having the silicon sharp structure formed thereon
according to a preferred embodiment of the present invention;
[0041] FIG. 5 is the schematic diagram illustrating the silicon
sharp structure having the metal catalyst layer formed thereon
according to a preferred embodiment of the present invention.
[0042] FIG. 6(a) is the schematic diagram illustrating the second
silicon substrate is imprinted with the silicon sharp structure
according to a preferred embodiment of the present invention;
[0043] FIG. 6(b) is the schematic diagram illustrating the second
silicon substrate having plural vestiges according to a preferred
embodiment of the present invention;
[0044] FIG. 7 is the schematic diagram illustrating the formation
of the carbon nanotubes according to a preferred embodiment of the
present invention;
[0045] FIG. 8(a) is the schematic diagram illustrating the third
silicon substrate having a metal catalyst layer formed thereon
according to another preferred embodiment of the present
invention;
[0046] FIG. 8(b) is the schematic diagram illustrating the third
silicon substrate having a metal catalyst layer formed thereon
imprinted with the silicon sharp structure according to another
preferred embodiment of the present invention;
[0047] FIG. 9 is the schematic diagram illustrating the silicon
sharp structure having a metal catalyst ball formed thereon
according to another preferred embodiment of the present invention;
and
[0048] FIG. 10 is the schematic diagram illustrating the formation
of the carbon nanotubes according to another preferred embodiment
of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0049] The present invention will now be described more
specifically with reference to the following embodiments. Please
refer to FIG. 1, which is a schematic diagram illustrating the
silicon substrate coated with the silicon oxide masking layer
thereon according to a preferred embodiment of the present
invention. As shown in FIG. 1, the silicon oxide masking layer 2
with a thickness of 5000 .ANG. is formed on the first silicon
substrate 1 under 1050.degree. C. as an etching masking layer.
[0050] Please refer to FIGS. 2(a).about.(b). FIG. 2(a) is a
schematic diagram illustrating the photolithography process
according to a preferred embodiment of the present invention. FIG.
2(b) is a schematic diagram illustrating the silicon oxide masking
layer having the covered photoresist layer formed thereon according
to a preferred embodiment of the present invention. As shown in
FIG. 2(a), the photoresist layer 3 is coated on the silicon oxide
masking layer 2. Then, the structure is exposed under the system
having the light source 5 and the mask 4. Further, the photoresist
layer 3 can be divided into the covered photoresist portion 32,
which is sheltered from the mask 4, and the naked photoresist
portion 31, which is not sheltered from the mask 4. The naked
photoresist portion 31 will be decomposed via being exposed under
the light source 5, and the decomposed result is shown in FIG.
2(b).
[0051] Please refer to FIGS. 2(b) and 3. FIG. 3 is the schematic
diagram illustrating the silicon substrate having the covered
silicon oxide masking layer formed thereon according to a preferred
embodiment of the present invention. After the naked phototresis
portion 31 is completely decomposed, a first etching is performed
by a BOE (Buffer Oxide Etching) solution containing some
hydrofluoric acid therein. At this moment, the naked silicon oxide
masking portion 21, which is not sheltered by the covered
photoresist portion 32, is etched by the BOE solution. On the other
hand, the covered silicon oxide masking portion 22, which is
sheltered by the covered photoresist portion 32, is remained. Then
the covered photoresist portion 32 is etched and removed by the
acetone solution. Therefore, the first silicon substrate 1 having
the covered silicon oxide masking portion 22 formed thereon is
accomplished, and the corresponding result is shown in FIG. 3.
[0052] Please refer to FIGS. 3 to 4. FIG. 4 is a schematic diagram
illustrating the silicon substrate having the sharp structures
formed thereon according to a preferred embodiment of the present
invention. After the above structure is accomplished, a chemical
etching is then performed by the potassium hydroxide solution.
Because the covered silicon oxide masking portion 22 has a better
resistance to the potassium hydroxide solution than that of the
first silicon substrate 1, the naked silicon substrate 11, which is
not sheltered by the covered silicon oxide masking portion 22, will
be etched and sunken downward continuously. After the silicon oxide
masking portion 22 is completely etched, the chemical etching
process will be stopped. At this moment, the first silicon
substrate 1 having plural silicon sharp structures 12 is
accomplished, and the corresponding result is shown in FIG. 4.
[0053] Please refer to FIGS. 4 to 5. FIG. 5 is a schematic diagram
illustrating the silicon sharp structure having a metal catalyst
layer formed thereon according to a preferred embodiment of the
present invention. The first metal catalyst layer 6 is coated on
the silicon sharp structures 12 of the first silicon substrate 1 by
the physical vapor deposition method, and the corresponding result
is shown in FIG. 5. In which, the first metal catalyst is selected
from a group consisting of a ferrum, a cobalt, and a nickel.
[0054] Please refer to FIGS. 6(a).about.(b). FIG. 6(a) is a
schematic diagram illustrating a second silicon substrate imprinted
with the silicon sharp structure according to a preferred
embodiment of the present invention. FIG. 6(b) is a schematic
diagram illustrating the second silicon substrate having plural
vestiges according to a preferred embodiment of the present
invention. As shown in FIG. 6(a), the second silicon substrate 7 is
imprinted with the silicon sharp structures 12, and the
corresponding result is shown in FIG. 6(b). As shown in FIG. 6(b),
the second silicon substrate 7 will have plural the vestiges 71,
and each vestige 71 has a metal catalyst ball 61 thereon. The
diameter of the metal catalyst ball 61 is determined by the
imprinting degree. Only when the diameter of the metal catalyst
ball 61 is less than 200 nm, the manufacturing process of growing
the carbon nanotubes will then be proceeded.
[0055] Please refer to FIG. 7. FIG. 7 is a schematic diagram
illustrating the formation of the carbon nanotubes according to a
preferred embodiment of the present invention. As show in FIG. 7,
the first carbon nanotubes 8 are grown from the vestiges 71 by
catalyzing with the metal catalyst balls 61. In which, every single
first carbon nanotube 8 is grown from every single one vestige 71,
and all the grown carbon nanotubes 8 have the same direction. At
this moment, a manufacturing process for growing single carbon
nanotube on a selective area is accomplished, and all the grown
carbon nanotubes have the same direction.
[0056] Another preferred embodiment of the present invention is
described as follows. Please refer to FIGS. 8(a).about.(b). FIG.
8(a) is a schematic diagram illustrating the silicon substrate
having a metal catalyst layer formed thereon according to another
preferred embodiment of the present invention. FIG. 8(b) is a
schematic diagram illustrating the third silicon substrate having a
metal catalyst layer formed thereon imprinted by the silicon sharp
structure according to another embodiment of the present invention.
As shown in FIG. 8(a), the second metal catalyst layer 10 is coated
on the third silicon substrate 9 by the physical vapor deposition
method. In which, the second metal catalyst is selected from a
group consisting of a ferrum, a cobalt, and a nickel.
[0057] Then, the silicon substrate 1 having the silicon sharp
structure 12 (as shown in FIG. 4) is imprinted with the third
silicon substrate 9, and the relevant imprinting method is shown in
FIG. 8(b).
[0058] Please refer to FIG. 9. FIG. 9 is a schematic diagram
illustrating the silicon sharp structure having the metal catalyst
ball thereon according to another embodiment of the present
invention. As shown in FIGS. 8(b) and 9, some metal residuum
(second metal catalyst balls 101) are remained on the tips of the
silicon sharp structure 12 after being imprinted with the second
metal catalyst layer 10. The diameter of the metal catalyst ball
101 is determined by the imprinting degree. Only when the diameter
of the metal catalyst ball 101 is less than 200 nm, the
manufacturing process of growing the carbon nanotubes will be
proceeded.
[0059] Please refer to FIG. 10, which is the formation of the
carbon nanotubes according to another embodiment of the present
invention. As shown in FIG. 10, the second carbon nanotubes 81 are
grown from the tip of the silicon sharp structures 12 by catalyzing
with the metal catalyst balls 101. In which, every single second
carbon nanotube 81 is grown from every single one silicon sharp
structure 12, and all the grown carbon nanotubes 81 have the same
direction. At this moment, another manufacturing process for
growing single carbon nanotube on a selective area is accomplished
and all the grown carbon nanotubes have the same direction.
[0060] As the above-mentioned description, since the sites for
growing carbon nanotubes are decided by using the metal imprint
technique, in the present invention, it is easy to control the
densities, the growing directions, and the diameters of the grown
carbon nanotubes. Furthermore, the present invention provides
methods for growing carbon nanotubes having a desired density on
the selective areas, so that it is possible to obtain the greatest
benefits while considering the cost and the practical value.
Additionally, the invention provides a manufacturing process for
forming carbon nanotubes having the same direction, so that
relevant products made of the carbon nanitubes will reveal the
particular characteristics of the carbon nanotubes, such as great
heat conductivity and high electricity conductivity. Therefore, the
invention has originality, novelty and progressiveness. Thus, the
present invention effectively improves the defaults of the prior
arts and has utility for the industries.
[0061] While the invention has been described in terms of what is
presently considered to be the most practical and preferred
embodiments, it is to be understood that the invention needs not be
limited to the disclosed embodiment. On the contrary, it is
intended to cover various modifications and similar arrangements
included within the spirit and scope of the appended claims which
are to be accorded with the broadest interpretation so as to
encompass all such modifications and similar structures.
* * * * *