U.S. patent application number 16/721782 was filed with the patent office on 2020-04-23 for graphene synthesis chamber and method of synthesizing graphene by using the same.
This patent application is currently assigned to HANWHA AEROSPACE CO., LTD.. The applicant listed for this patent is HANWHA AEROSPACE CO., LTD. NPS Corporation. Invention is credited to Won-Sik NAM, Dong-kwan WON.
Application Number | 20200123658 16/721782 |
Document ID | / |
Family ID | 46827431 |
Filed Date | 2020-04-23 |
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United States Patent
Application |
20200123658 |
Kind Code |
A1 |
WON; Dong-kwan ; et
al. |
April 23, 2020 |
GRAPHENE SYNTHESIS CHAMBER AND METHOD OF SYNTHESIZING GRAPHENE BY
USING THE SAME
Abstract
A graphene synthesis chamber includes: a chamber case in which a
substrate including a metal thin film is placed; a gas supply unit
which supplies at least one gas comprising a carbon gas into an
inner space of the chamber case; a main heating unit which emits at
least one light to the inner space to heat the substrate; and at
least one auxiliary heating unit which absorbs the at least one
light and emits radiant heat toward the substrate.
Inventors: |
WON; Dong-kwan; (Seoul,
KR) ; NAM; Won-Sik; (Hwaseong-city, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HANWHA AEROSPACE CO., LTD.
NPS Corporation |
Changwon-si
Hwaseong-si |
|
KR
KR |
|
|
Assignee: |
HANWHA AEROSPACE CO., LTD.
Changwon-si
KR
NPS Corporation
Hwaseong-si
KR
|
Family ID: |
46827431 |
Appl. No.: |
16/721782 |
Filed: |
December 19, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15204907 |
Jul 7, 2016 |
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16721782 |
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13416071 |
Mar 9, 2012 |
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15204907 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C23C 16/482 20130101;
C23C 16/545 20130101; B82Y 40/00 20130101; C23C 16/46 20130101;
C23C 16/26 20130101 |
International
Class: |
C23C 16/46 20060101
C23C016/46; C23C 16/48 20060101 C23C016/48; B82Y 40/00 20060101
B82Y040/00; C23C 16/54 20060101 C23C016/54; C23C 16/26 20060101
C23C016/26 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 17, 2011 |
KR |
10-2011-0023829 |
Jul 13, 2011 |
KR |
10-2011-0069490 |
Claims
1. A graphene synthesis method comprising: disposing a substrate
including a metal thin film in an inner space of a graphene
synthesis chamber; depressurizing the inner space; supplying a gas
including carbon into the inner space using a gas supplier; and
irradiating a light to the inner space to heat the substrate using
a main heating unit, wherein a first auxiliary heating unit and a
second auxiliary heating unit are disposed at both sides of the
substrate, respectively, and spaced apart from each other so as to
define an auxiliary space therebetween for synthesizing graphene on
the substrate, and wherein the substrate is disposed in the
auxiliary space, and spaced apart from the first auxiliary heating
unit and the second auxiliary heating unit.
2. The graphene synthesis method of claim 1, wherein a temperature
of the auxiliary space is about 1000.degree. C. or higher during
graphene synthesis.
3. The graphene synthesis method of claim 1, wherein a temperature
of the auxiliary space is substantially constant during graphene
synthesis.
4. The graphene synthesis method of claim 1, wherein the main
heating unit comprises: a first main heating unit which faces a
first surface of the substrate; and a second main heating unit
which faces a second surface of the substrate.
5. The graphene synthesis method of claim 4, wherein the first
auxiliary heating unit is provided between the first main heating
unit and the substrate, and the second auxiliary heating unit is
provided between the second main heating unit and the
substrate.
6. The graphene synthesis method of claim 4, wherein a temperature
of the auxiliary space is higher than (i) a temperature of a space
between the first main heating unit and the first auxiliary heating
unit, and (ii) a temperature of a space between the second main
heating unit and the second auxiliary heating unit.
7. The graphene synthesis method of claim 1, wherein the gas
supplier supplies the gas into the auxiliary space.
8. The graphene synthesis method of claim 1, wherein the main
heating unit comprises: a halogen lamp; and a window surrounding an
outer circumference of the halogen lamp.
9. The graphene synthesis method of claim 1, wherein the gas
supplier comprises an extension portion extending toward the
auxiliary space.
10. The graphene synthesis method of claim 1, wherein the graphene
chamber comprises: a gas discharger which discharges the gas
flowing through the auxiliary space to an outside.
11. The graphene synthesis method of claim 10, wherein the gas
discharger comprises an extension portion extending toward the
auxiliary space.
12. The graphene synthesis method of claim 1, wherein each of the
first auxiliary heating unit and the second auxiliary heating unit
comprises graphite.
Description
CROSS-REFERENCE TO THE RELATED APPLICATIONS
[0001] This is a Rule 53(b) Divisional Application of U.S.
application Ser. No. 15/204,907 filed Jul. 7, 2016, which is a Rule
53(b) Continuation of U.S. application Ser. No. 13/416,071 filed
Mar. 9, 2012, claiming priority from Korean Patent Application No.
10-2011-0023829 filed on Mar. 17, 2011, and Korean Patent
Application No. 10-2011-0069490, filed on Jul. 13, 2011, the
contents of all of which are incorporated herein by reference in
their entirety.
BACKGROUND
1. Field
[0002] Apparatuses and method consistent with exemplary embodiments
relate to a graphene synthesis chamber and synthesizing graphene by
using the same.
2. Description of the Related Art
[0003] In general, graphite is a stack of two-dimensional (2D)
graphene sheets having a plate shape in which carbon atoms are
connected to one another in a hexagonal shape. After examining
graphene peeled off from graphite, it has been found recently that
graphene has very useful properties that are different from those
of existing materials.
[0004] One remarkable property of graphene is that when electrons
move therein, the electrons move as if the mass of the electrons is
zero. This means that the electrons move at a speed at which light
travels in vacuum, that is, at the speed of light. Graphene
exhibits an abnormal half-integer quantum Hall effect with respect
to electrons and holes, and also has a high electron mobility
ranging from about 20,000 to about 50,000 cm.sup.2/Vs.
[0005] In order to synthesize graphene, chemical vapor deposition
(CVD) is used. CVD is a method of synthesizing graphene on a
surface of a metal thin film by putting the metal thin film formed
of a catalytic metal such as copper or platinum in an inner space
of a graphene synthesis chamber, injecting hydrocarbon such as
methane or ethane into the inner space of the graphene synthesis
chamber, and heating the inner space of the graphene synthesis
chamber at a high temperature.
[0006] Although graphene has very useful properties as described
above, since it takes a relatively long time to set a
high-temperature/high-vacuum environment in order to synthesize
graphene, it is difficult to mass produce large graphene sheets at
low costs.
SUMMARY
[0007] One or more exemplary embodiments provide a graphene
synthesis chamber allowing easy thermal control.
[0008] According to one aspect of an exemplary embodiment, there is
provided a graphene synthesis chamber including: a chamber case in
which a substrate including a metal thin film is placed; a gas
supply unit which supplies at least one gas comprising a carbon gas
into an inner space of the chamber case; a main heating unit which
emits at least one light to the inner space to heat the substrate;
and at least one auxiliary heating unit which absorbs the at least
one light and emits radiant heat toward the substrate.
[0009] The at least one auxiliary heating unit may be disposed
parallel to at least one of a first surface and a second surface of
the substrate.
[0010] The at least one auxiliary heating unit may include: a first
auxiliary heating portion which faces a first surface of the
substrate; and a second auxiliary heating portion which faces a
second surface, opposite to the first surface, of the
substrate.
[0011] The first auxiliary heating portion may be spaced apart from
the substrate.
[0012] The gas supply unit may be disposed at a first side of an
auxiliary space formed by the first auxiliary heating portion and
the second auxiliary heating portion in the inner space, and may
supply the at least one gas into the auxiliary space.
[0013] The graphene synthesis chamber may further include a gas
discharge unit which is disposed at second side of the auxiliary
space and discharge the at least one gas flowing through the
auxiliary space to an outside.
[0014] The main heating unit may include: a halogen lamp; and a
window which is disposed in a direction in which the halogen lamp
emits the at least one light or surrounds an outer circumference of
the halogen lamp.
[0015] The at least one light may include a near-infrared
wavelength band light, and at least one of a mid-infrared
wavelength band light and a visible wavelength band light, wherein
the at least one gas may further include at least one of an inert
gas and a non-reactive gas which is heated by at least one of the
three lights.
[0016] The main heating unit may be disposed on at least one of a
central region of the chamber case and a region adjacent to an
inner surface of the chamber case, wherein the at least one
auxiliary heating unit is a plurality of auxiliary heating units
disposed parallel to the inner surface of the chamber case.
[0017] The chamber case may be a polyhedron.
[0018] The graphene synthesis chamber may further include at least
one barrier wall which divides the inner space of the chamber case
into at least two spaces, wherein the at least one gas may further
include at least one of an inert gas and a non-reactive gas which
is heated by the at least one light, in a first space of the at
least two spaces, and the at least one auxiliary heating unit may
be disposed in a second space of the at least two spaces where the
carbon gas is heated by the at least one light and the radiant
heat.
[0019] The at least one light may include a near-infrared
wavelength band light, a mid-infrared wavelength band light and a
visible wavelength band light, wherein the at least one of the
inert gas and the non-reactive gas is heated by at least one of the
three lights, and the carbon gas is heated by at least one of the
three lights and the radiant heat to form graphene on the
substrate.
[0020] The chamber case may further include: a metal thin film
inlet/outlet through which the substrate is introduced into the
chamber case, and the substrate on which graphene is formed is
output from the chamber case, wherein the metal thin film
inlet/outlet may include at least one gap which closes in a vacuum
state on the inner space of the chamber case, and opens when the
substrate on which the graphene is formed passes through the
chamber case.
[0021] A first gap among the at least one gap may be disposed at a
side where the substrate is introduced into the chamber case, and
the first gap may be substantially equal to a thickness of the
substrate before the graphene is formed thereon.
[0022] A second gap may be disposed at a side where the substrate
on which the graphene is formed is output from the chamber case,
and the second gap may be substantially equal to a sum of
thicknesses of the graphene and the substrate.
[0023] The metal thin film inlet/outlet may include rotating
members which roll the substrate into the chamber. The rotating
members may linearly contact the substrate when the substrate moves
in the first gap.
[0024] Surfaces of the rotating members contacting the metal thin
film of the substrate may include a material having a hardness less
than a hardness of the metal thin film.
[0025] The graphene synthesis chamber may further include loadlock
chambers which are disposed outside the chamber case with the at
least one gap between the loadlock chambers and the chamber
case.
[0026] The graphene synthesis chamber may further include metal
thin film protecting units which are disposed in the chamber case
and protect portions of the substrate from the gas, wherein the
portions of the substrate are wound around rollers
[0027] The metal thin film protecting units may include a material
that evaporates at a temperature higher than a temperature at which
the graphene is formed on the substrate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The above and other aspects will become more apparent by
describing in detail exemplary embodiments thereof with reference
to the attached drawings, in which:
[0029] FIGS. 1A and 1B are cross-sectional views illustrating a
substrate including a metal thin film according to an exemplary
embodiment;
[0030] FIG. 2 is a cross-sectional view illustrating a graphene
synthesis chamber according to an exemplary embodiment;
[0031] FIG. 3 is a cross-sectional view illustrating a main heating
unit modified from a main heating unit of the graphene synthesis
chamber of FIG. 2, according to an exemplary embodiment;
[0032] FIG. 4 is a cross-sectional view illustrating a graphene
synthesis chamber according to another exemplary embodiment;
[0033] FIG. 5 is a cross-sectional view illustrating a graphene
synthesis chamber according to another exemplary embodiment;
[0034] FIG. 6 is an enlarged cross-sectional view illustrating a
portion VI of FIG. 5;
[0035] FIG. 7 is a perspective view illustrating a part of a
graphene synthesis chamber according to another exemplary
embodiment;
[0036] FIG. 8 is a cross-sectional view taken along line VII-VII of
FIG. 7;
[0037] FIG. 9 is a graph illustrating a Raman spectrum of graphene
synthesized in the graphene synthesis chamber of FIG. 4, according
to an exemplary embodiment;
[0038] FIG. 10 is a cross-sectional view illustrating a graphene
synthesis chamber according to another exemplary embodiment;
[0039] FIG. 11 is a cross-sectional view illustrating a portion XI
of a metal thin film of FIG. 10;
[0040] FIG. 12 is a cross-sectional view illustrating a portion XII
of graphene formed on the metal thin film of FIG. 10;
[0041] FIG. 13 is a perspective view illustrating a portion XIII of
the metal thin film introduced through a metal thin film
inlet/outlet of FIG. 10;
[0042] FIG. 14 is a perspective view illustrating a portion XIV of
the graphene and the metal thin film discharged through the metal
thin film inlet/outlet of FIG. 10;
[0043] FIG. 15 is a cross-sectional view illustrating a graphene
synthesis chamber according to another exemplary embodiment;
[0044] FIG. 16 is a cross-sectional view illustrating a graphene
synthesis chamber according to another exemplary embodiment;
[0045] FIG. 17 is a cross-sectional view illustrating a portion
XVII of a metal thin film of FIG. 16;
[0046] FIG. 18 is a cross-sectional view illustrating a portion
XVIII of graphene formed on the metal thin film of FIG. 16; and
[0047] FIG. 19 is a cross-sectional view illustrating a graphene
synthesis chamber according to another exemplary embodiment.
DETAILED DESCRIPTION EXEMPLARY EMBODIMENTS
[0048] The advantages and features of the inventive concept and
methods of achieving the advantages and features will be described
more fully with reference to the accompanying drawings, in which
exemplary embodiments are shown. The inventive concept may,
however, be embodied in many different forms and should not be
construed as being limited to the embodiments set forth herein;
rather these embodiments are provided so that this disclosure will
be thorough and complete, and will fully convey the inventive
concept to one of ordinary skill in the art. Meanwhile, the
terminology used herein is for the purpose of describing particular
embodiments only and is not intended to be limiting of inventive
concept. As used herein, the singular forms "a," "an" and "the" are
intended to include the plural forms as well, unless the context
clearly indicates otherwise. It will be further understood that the
terms "comprises" and/or "comprising" used herein specify the
presence of stated features, integers, steps, operations, members,
components, and/or groups thereof, but do not preclude the presence
or addition of one or more other features, integers, steps,
operations, members, components, and/or groups thereof. It will be
understood that, although the terms first, second, etc. may be used
herein to describe various elements, these elements should not be
limited by these terms. These terms are only used to distinguish
one element from another.
[0049] Herein, "a substrate including a metal thin film
(hereinafter, referred to as a substrate)" 10 may be a substrate
10a which includes a base layer 11 and a metal thin film layer 12
formed on a base layer 11 as shown in FIG. 1A, or may be a
substrate 10b which is a single layer as shown in FIG. 1B.
[0050] Referring to FIG. 1A, if the substrate 10 is the substrate
10a including the base layer 11 and the metal thin film layer 12
formed on the base layer 11, the base layer 11 may be formed of an
inorganic material such as silicon (Si), glass, GaN, or silica, or
a metal such as nickel (Ni), copper (Cu), or tungsten (W).
Alternatively, the base layer 11 may be formed of SiO.sub.2,
Si.sub.3N.sub.4, SiON, SIOF, BN, hydrogen silsesquiloxane (HSQ),
xerogel, aero gel, poly naphthalene, amorphous carbon fluoride
(a-CF), SiOC, MSQ, black diamond, or the like.
[0051] The metal thin film layer 12 may be formed on the base layer
11 by using a sputtering device, an electron beam evaporation
device, or the like. The metal thin film layer 12 may include at
least one metal selected from the group consisting of nickel (Ni),
cobalt (Co), iron (Fe), platinum (Pt), gold (Au), silver (Ag),
aluminum (Al), chromium (Cr), copper (Cu), magnesium (Mg),
manganese (Mn), molybdenum (Mo), rhodium (Rh), silicon (Si),
tantalum (Ta), titanium (Ti), tungsten (W), uranium (U), vanadium
(V), palladium (Pd), yttrium (Y), and zirconium (Zr).
[0052] Referring to FIG. 1B, the substrate 10b, which includes a
single metal thin film, may include a metal selected from the group
consisting of Ni, Co, Fe, Pt, Au, Ag, Al, Cr, Cu, Mg, Mn, Mo, Rh,
Si, Ta, Ti, W, U, V, Pd, Y, and Zr.
[0053] A case where a substrate includes a single metal thin film
will be explained for convenience.
[0054] FIG. 2 is a cross-sectional view illustrating a graphene
synthesis chamber 100 according to an exemplary embodiment.
[0055] Referring to FIG. 2, the graphene synthesis chamber 100
includes a chamber case 110 and a main heating unit 120.
[0056] The chamber case 110 defines an inner space I in which the
substrate 10 may be placed. For example, the chamber case 110 may
include a first chamber case 111 which is an upper case and a
second chamber case 112 which is a lower case, and the inner space
I may be formed between the first and second chamber cases 111 and
112. A stage (not shown) on which the substrate 10 is placed may be
disposed in the inner space I.
[0057] The graphene synthesis chamber 100 may include a first
depressurization unit 101 or a second depressurization unit 103 in
order to depressurize the inner space I. Alternatively, the
graphene synthesis chamber 100 may include both the first and
second depressurization units 101 and 103. In this case, the first
depressurization unit 101 may be disposed at a first side and the
second depressurization unit 103 may be disposed at a second side
opposite to the first side. The inner space I of the graphene
synthesis chamber 100 may be depressurized to a pressure of about
several hundred torr to about 10.sup.-3 torr by discharging a gas
in the inner space I to the outside through the first and second
depressurization units 101 and 103.
[0058] A gas supply unit 102 is disposed on a first side of the
graphene synthesis chamber 100, and supplies a gas including carbon
into the inner space I. The gas including carbon, which is a
reactive gas for forming graphene, may be at least one selected
from the group consisting of carbon monoxide (CO), carbon dioxide
(CO.sub.2), ethane (C.sub.2H.sub.6), ethylene (CH.sub.2), ethanol
(C.sub.2H.sub.5), acetylene (C.sub.2H.sub.2), propane
(CH.sub.3CH.sub.2CH.sub.3), propylene (C.sub.3H.sub.6), butane
(C.sub.4H.sub.10), butadiene (C.sub.4H.sub.6), pentane
(CH.sub.3(CH.sub.2).sub.3CH.sub.3), pentene (C.sub.5H.sub.10),
cyclopentadiene (C.sub.5H.sub.6), hexane (C.sub.6H.sub.14),
cyclohexane (C.sub.6H.sub.12), benzene (C.sub.6H.sub.6), and
toluene (C.sub.7H.sub.8).
[0059] Meanwhile, the gas supply unit 102 may supply not only the
gas including carbon but also an atmospheric gas into the inner
space I. The atmospheric gas may include an inert gas such as
helium or argon, and a non-reactive gas such as hydrogen for
maintaining a surface of the metal thin film clean.
[0060] Although the gas supply unit 102 supplies the gas including
carbon and the atmospheric gas in FIG. 2, the present embodiment is
not limited thereto. For example, a gas supply unit for supplying a
gas including carbon and a gas supply unit for supplying an
atmospheric gas may be separately disposed, and may respectively
supply the gas including carbon and the atmospheric gas into the
inner space I.
[0061] A gas discharge unit 104 is disposed on a second side of the
graphene synthesis chamber 100 opposite to the first side, and
discharges remaining gases left after being used to synthesize
graphene in the inner space I to the outside. According to an
exemplary embodiment, the gas discharge unit 104, instead of the
first and second depressurization units 101 and 103, may be used to
discharge a gas in the inner space I to the outside before the
atmospheric gas and the gas including carbon are supplied into the
inner space I.
[0062] The main heating unit 120 emits light having a near-infrared
wavelength band into the inner space I. The light having the
near-infrared wavelength band may mainly heat the substrate 100.
The light having the near-infrared wavelength band may be directly
emitted to the substrate 10 to uniformly increase a temperature of
the substrate 10 and rapidly reach a temperature needed to
synthesize graphene.
[0063] If an inner space of a chamber is heated by using an
inductor coil, since the entire inner space of the chamber is
heated, it takes a long time to reach a temperature needed to
synthesize graphene, and it also takes a long time to reduce the
temperature after the graphene is synthesized. Meanwhile, since the
graphene synthesis chamber 100 uses light having a near-infrared
wavelength band, a temperature may be easily controlled, the
substrate 100 may be rapidly heated to a temperature needed to
synthesize graphene without heating the entire inner space I, and a
temperature may be uniformly increased irrespective of a position
of the substrate 10.
[0064] The main heating unit 120 may emit light having at least one
of a mid-infrared wavelength band and a visible wavelength band as
well as the light having the near-infrared wavelength band. The
light having the mid-infrared wavelength band or the visible
wavelength band may heat the gas including carbon supplied into the
graphene synthesis chamber 100.
[0065] Since the light having the near-infrared wavelength band
heats the substrate 10, and the light having the mid-infrared
wavelength band and the visible wavelength band heats the gas
including carbon, temperatures of outer walls of the first and
second chamber cases 111 and 112 may be lower than a temperature of
the substrate 10. That is, since only the substrate 10 and
surroundings of the substrate 10 are heated without heating the
entire graphene synthesis chamber 100, a temperature needed to
synthesize graphene may efficiently be controlled. Since a time
taken to increase a temperature to a temperature needed to
synthesize graphene and a time to reduce the temperature are
reduced in this configuration, graphene may be mass produced.
[0066] Also, compared to the aforesaid chamber having the inner
space which is heated by using the inductor coil, the graphene
synthesis chamber 100 may minimize unnecessary substances, for
example, impurities, deposited on an outer wall or a pipe of the
graphene synthesis chamber 100.
[0067] The main heating unit 120 may include lamps 121 and windows
122. The plurality of lamps 121 may be spaced apart from one
another. The lamps 121 may be halogen lamps. The halogen lamps emit
light having a near-infrared wavelength band, a mid-infrared
wavelength band, and/or a visible wavelength band.
[0068] The windows 122 may be formed of a transparent material such
as quartz, and may surround outer circumferential surfaces of the
lamps 121. The windows 112 may protect the lamps 121 and may
improve luminous efficiency.
[0069] A process of synthesizing graphene in the graphene synthesis
chamber 100 described above will now be explained.
[0070] First, the substrate 10 is placed in the inner space I, and
then, a gas in the inner space I is discharged to the outside
through the first and second depressurization units 101 and 103 by
using a vacuum pump (not shown). A pressure in the inner space I
may be of about several hundred torr to about 10.sup.-6 torr.
[0071] Next, an atmospheric gas may be injected into the inner
space I through the gas supply unit 102. The atmospheric gas may be
an inert gas such as helium or argon, and/or a non-reactive gas
such as hydrogen for maintaining the surface of the metal thin film
clean.
[0072] After the atmospheric gas is injected, the substrate 10 is
heated by using the main heating unit 120, and a gas including
carbon, that is, a reactive gas, is supplied through the gas supply
unit 102 when a temperature of the substrate 10 is sufficiently
high.
[0073] When the substrate 10 is heated due to light having a
near-infrared wavelength band emitted from the main heating unit
120, a temperature of the substrate 10 is increased. Due to the
increase in the temperature of the substrate 10, temperatures of
surroundings of the substrate 10 also locally increase, and thus,
thermal energy is supplied to the gas including carbon. Also, since
thermal energy is supplied to the gas including carbon due to light
having a visible wavelength band and/or a mid wavelength band
emitted from the main heating unit 120, a condition needed to
synthesize graphene is rapidly achieved. For example, the gas
including carbon may be decomposed such that the gas including
carbon is absorbed into the metal thin film.
[0074] FIG. 3 is a cross-sectional view illustrating a main heating
unit 120' modified from the main heating unit 120 of the graphene
synthesis chamber 100 of FIG. 2, according to an exemplary
embodiment.
[0075] Referring to FIG. 3, the main heating unit 120' may include
lamps 121' that are spaced apart from one another at predetermined
intervals, and a window 122' that is disposed adjacent to the lamps
121' in a direction (hereinafter, referred to as a light emission
direction) in which the lamps 121' emit light. The windows 122 of
FIG. 2 surround the outer circumferential surfaces of the lamps
121, and the window 122' of FIG. 3 is disposed beside the lamps
121' that are aligned at predetermined intervals. According to
another according to an exemplary embodiment, the intervals between
the lamps 121' may not be the same and may be adjusted to increase
an overall efficiency of light emitted from the lamps 121'. This
embodiment may apply to the other structures of a main heating unit
of a graphene synthesis chamber described in the present
application.
[0076] FIG. 4 is a cross-sectional view illustrating a graphene
synthesis chamber 200 according to another exemplary
embodiment.
[0077] Referring to FIG. 4, the graphene synthesis chamber 200
includes a chamber case 210 and main heating units 220, first and
second depressurization units 201 and 203 for depressurizing an
inner space I of the chamber case 210, and a gas supply unit 202
and a gas supply discharge unit 204 for respectively introducing
and discharging a gas including carbon and an atmospheric gas
needed to synthesize graphene, like the graphene synthesis chamber
100 of FIG. 2, and thus, an explanation thereof will not be
given.
[0078] However, the graphene synthesis chamber 200 is different
from the graphene synthesis chamber 100 in that the main heating
units 220 are disposed over and under the substrate 10.
[0079] The main heating units 220 each including lamps 221 and a
window 222 are disposed over and under the substrate 10. The main
heating units 220 may each include the lamps 221 and the window
222. The lamps 221 may be halogen lamps. The halogen lamps may emit
light having a near-infrared wavelength band, a mid-infrared
wavelength band, and/or a visible wavelength band to the top and
the bottom of the substrate 10.
[0080] Since light is simultaneously emitted from the main heating
units 220 that are disposed over and under the substrate 10, a
temperature of the substrate 10 may be uniformly increased, and a
time taken to increase the temperature may be reduced, thereby
reducing a time taken to synthesize graphene. For an overall
efficiency, however, the light may not be simultaneously emitted
from the main heating unit 220.
[0081] FIG. 5 is a cross-sectional view illustrating a graphene
synthesis chamber 300 according to another exemplary embodiment.
FIG. 6 is a cross-sectional view illustrating a portion VI of FIG.
5.
[0082] Referring to FIG. 5, the graphene synthesis chamber 300
includes a chamber case 310, first and second depressurization
units 301 and 303 for depressurizing an inner space I of the
chamber case 310, a gas supply unit 302 and a gas discharge unit
304 for respectively introducing and discharging a gas including
carbon needed to synthesize graphene, and an auxiliary heating unit
330. The following explanation will be made by focusing on the
differences between the embodiments.
[0083] A main heating unit 320 emits light having a near-infrared
wavelength band into the inner space I to mainly heat the substrate
10. The light having the near-infrared wavelength band may be
directly emitted to the substrate 10 to uniformly increase a
temperature of the substrate 10 and help to rapidly reach a
temperature needed to synthesize graphene.
[0084] The auxiliary heating unit 330 may face at least one surface
of a first surface and a second surface of the substrate 10. For
example, the auxiliary heating unit 330 may include a first
auxiliary heating portion 331 and a second auxiliary heating
portion 332 which are disposed at both sides of the substrate
10.
[0085] The first auxiliary heating portion 331 and the second
auxiliary heating portion 332 may face each other to be spaced
apart from each other, thereby defining an auxiliary space S. For
example, the first auxiliary heating portion 331 may face the first
surface of the substrate 10 to be spaced apart from the substrate
10, and the second auxiliary heating portion 332 may face the
second surface of the substrate 10. The first and second auxiliary
heating portions 331 and 332 may be formed such that the auxiliary
space S is rapidly optimized to perform graphene synthesis.
[0086] Temperatures of the first and second auxiliary heating
portions 331 and 332 may increase due to the light having the
near-infrared wavelength band emitted from the main heating unit
320. Each of the first and second auxiliary heating portions 331
and 332 may be formed of any material as long as a temperature of
the material may increase due to the light having the near-infrared
wavelength band. For example, each of the first and second
auxiliary heating portions 331 and 332 may include a metal or
graphite.
[0087] When the substrate 10 is heated due to the light having the
near-infrared wavelength band, a temperature of the substrate 10
increases and temperatures of surroundings of the substrate 10 also
locally increase due to heat generated by the substrate 10. In this
case, the first and second auxiliary heating portions 331 and 332
are disposed around the substrate 10 to contain heat generated in
the surroundings of the substrate 10.
[0088] Also, since temperatures of the first and second auxiliary
heating portions 331 and 332 increase due to the light having the
near-infrared wavelength band, a temperature of the auxiliary space
S formed around the substrate 10 is higher than temperatures of
other spaces of the inner space I. That is, a temperature needed to
synthesize graphene may be more rapidly reached due to the first
and second auxiliary heating portions 331 and 332.
[0089] Since graphene synthesis occurs in the auxiliary space S, a
gas including carbon only needs to be supplied into the auxiliary
space S. Accordingly, in order to minimize generation or leakage of
a gas flowing to spaces other than the auxiliary space S, the gas
supply unit 302 may include an extension portion 302a that extends
toward the auxiliary space S. According to another exemplary
embodiment, however, the gas supply unit 302, without the extension
portion 302a, may be disposed such that the gas including carbon is
easily supplied into the auxiliary space S, thereby obtaining an
effect of extending the gas supply unit 302 toward the auxiliary
space S.
[0090] The gas discharge unit 304 that discharges remaining gases
left after the graphene synthesis also includes an extension
portion 304a to rapidly discharge the remaining gases, thereby
maintaining the auxiliary space S in an optimal state needed to
synthesize graphene. According to another exemplary embodiment,
however, the gas discharge unit 304, without the extension portion
304a, may be disposed such that the remaining gases are easily
discharged, thereby obtaining an effect of extending the gas
discharge unit 304 toward the auxiliary space S.
[0091] Although the main heating unit 320 is disposed only over the
substrate 10 in FIG. 5, the present embodiment is not limited
thereto. The main heating unit 320 may also be disposed both over
and under the substrate 10, like in FIG. 4.
[0092] Although one window 322 of the main heating unit 320 faces
one side surfaces of lamps 321 in FIG. 5, the main heating unit 320
may also include the lamps 321 and a plurality of the windows 322
surrounding outer circumferential surfaces of the lamps 321 like in
FIG. 2.
[0093] A process of synthesizing graphene in the graphene synthesis
chamber 300 constructed as described above will now be
explained.
[0094] First, the substrate 10 is placed in the inner space I, and
then, a gas in the inner space I is discharged to the outside
through the first and second depressurization units 301 and 303 by
using a vacuum pump (not shown). A pressure in the inner space I
may be of about several hundred torr to about 10.sup.-6 torr which
is lower than an atmospheric pressure.
[0095] Next, an atmospheric gas, for example, an inert gas such as
helium or argon and/or a non-reactive gas such as hydrogen for
maintaining the surface of the metal thin film clean, may be
injected through the gas supply unit 302. In this case, since by
using the extension portion 302a or positioning of the gas supply
unit 302, the atmospheric gas may be efficiently supplied into the
auxiliary space S.
[0096] After the atmospheric gas is injected, the substrate 10 and
the first and second auxiliary heating portions 331 and 332 are
heated by using the main heating unit 320. Referring to FIG. 6,
when temperatures of the substrate 10 and the first and second
auxiliary heating portions 331 and 332 sufficiently increase due to
light having a near-infrared wavelength band emitted from the main
heating unit 320, a temperature of the auxiliary space S increases
due to heat generated by the substrate 10 and the first and second
auxiliary heating portions 331 and 332 to a temperature high enough
to synthesize graphene. For example, temperatures of the auxiliary
space S and the substrate 10 may be about 1000.degree. C. or
higher.
[0097] Next, a gas including carbon, that is, a reactive gas G, is
supplied through the gas supply unit 302. In this case, by using
the extension portion 304a or positioning of the gas supply unit
304, the reactive gas G flows efficiently from the gas supply unit
302 through the auxiliary space S to the gas discharge unit 304.
The reactive gas G is supplied along with the thermal energy in the
auxiliary space S, and thus, is decomposed to synthesize
graphene.
[0098] When the reactive gas G passes through the auxiliary space S
having a high temperature, the reactive gas G contacts the
substrate 10, that is, an activated surface of the metal thin film.
The reactive gas G decomposed in this process is absorbed into the
metal thin film having the activated surface to grow graphene
crystals.
[0099] Although the substrate 10 is heated by the main heating unit
320, and then, a gas including carbon is supplied in FIG. 5, the
present embodiment is not limited thereto. For example, before the
main heating unit 320 emits light, when the main heating unit 320
emits light, or after the main heating unit 320 emits light, a gas
including carbon may be supplied. That is, the main heating unit
320 may operate before a gas including carbon is supplied, the main
heating unit 320 may operate while a gas including carbon is
supplied, or the main heating unit 320 may operate after a gas
including carbon is supplied.
[0100] Although the substrate 10 and the first and second auxiliary
heating portions 331 and 332 are heated due to light having a
near-infrared wavelength band emitted from the main heating unit
320, the auxiliary space S is heated by the substrate 10 and the
first and second auxiliary heating portions 331 and 332 emitting
heat H, and a gas including carbon, that is, a reactive gas G, is
decomposed in FIG. 5, the present embodiment is not limited
thereto. Alternatively, the main heating unit 320 may emit not only
light having a near-infrared wavelength band but also light having
a mid-infrared wavelength band and/or a visible wavelength
band.
[0101] In this case, the light having the near-infrared wavelength
band emitted from the main heating unit 320 may supply energy to
the substrate 10 and the first and second auxiliary heating
portions 331 and 332, and the auxiliary space S may be heated by
the substrate 10 and the first and second auxiliary heating
portions 331 and 332. At the same time, the light having the
mid-infrared wavelength band and/or the visible wavelength band
emitted from the main heating unit 320 may heat the gas including
carbon supplied into the auxiliary space S.
[0102] In other words, the gas including carbon may be decomposed
by receiving energy from heat of the auxiliary space S heated by
the substrate 10 and the first and second auxiliary heating
portions 331 and 332, and from light having a mid-infrared
wavelength band and/or a visible wavelength band. Accordingly,
graphene synthesis may more actively and rapidly occur in the
auxiliary space S.
[0103] FIG. 7 is a perspective view illustrating a part of a
graphene synthesis chamber 700 according to another exemplary
embodiment. FIG. 8 is a cross-sectional view taken along line
VII-VII of FIG. 7, according to an exemplary embodiment. First and
second depressurization units for depressurizing a chamber case 710
are not shown for convenience of explanation in FIGS. 7 and 8.
[0104] The chamber case 710 of the graphene synthesis chamber 700
may be a polyhedron. For example, the chamber case 710 may be a
polyhedron including a plurality of surfaces such as a hexahedron
or an octahedron. Graphene synthesis may occur in regions
corresponding to inner surfaces of the chamber case 710.
[0105] Referring to FIG. 7, the graphene synthesis chamber 700,
that is, the chamber case 710, may be a hexahedron. Auxiliary
heating units 730 may be disposed parallel to inner surfaces of the
chamber case 710. For example, the auxiliary heating units 730 may
be disposed along four inner surfaces in a front-and-back direction
and in a left-and-right direction of the chamber case 710, may be
disposed along two inner surfaces in an up-and-down direction of
the chamber case 710, or may be disposed along all of six inner
surfaces of the chamber case 710.
[0106] Each of the auxiliary heating units 730 disposed along inner
surfaces of the graphene synthesis chamber 700 may include a first
auxiliary heating portion 731 and a second auxiliary heating
portion 732 which are disposed at both sides of the substrate 10.
The first auxiliary heating portion 731 and the second auxiliary
heating portion 732 face each other to be spaced apart from each
other, thereby defining an auxiliary space therebetween. The
substrate 10 is disposed between the first and second auxiliary
heating portions 731 and 732 that are spaced apart from each
other.
[0107] Temperatures of the first and second auxiliary heating
portions 731 and 732 increase due to light having a near-infrared
wavelength band emitted from a main heating unit 720. Each of the
first and second auxiliary heating portions 731 and 732 may be
formed of any material as long as a temperature of the material may
increase due to the light having the near-infrared wavelength band.
For example, each of the first and second auxiliary heating
portions 731 and 732 may include a metal or graphite.
[0108] When the substrate 10 is heated due to the light having the
near-infrared wavelength band, a temperature of the substrate 10
increases and temperatures of surroundings of the substrate 10 also
locally increase due to heat generated in the substrate 10. In this
case, the first and second auxiliary heating portions 731 and 732
are disposed around the substrate 10 to contain heat generated in
the surroundings of the substrate 10. Also, since the first and
second auxiliary heating portions 731 and 732 are heated due to the
light having the near-infrared wavelength band, a temperature of
the auxiliary space formed around the substrate 10 is higher than
temperatures of other spaces in the graphene synthesis chamber 700.
That is, a temperature needed to synthesize graphene is more
rapidly reached by the first and second auxiliary heating portions
731 and 732.
[0109] Since graphene synthesis occurs in the auxiliary space, a
gas including carbon only needs to be supplied into the auxiliary
space. Accordingly, in order to minimize generation or leakage of a
gas flowing to spaces other than the auxiliary space, a gas supply
unit 702 may include an extension portion that extends toward the
auxiliary space, or may be positioned to efficiently supply the gas
toward the auxiliary space even without such extension portion.
[0110] The gas supply unit 702 is disposed near each auxiliary
space to supply a gas including carbon into each auxiliary space.
For example, the gas supply unit 702 may extend downward in the
chamber case 710 in order to supply a gas including carbon into
auxiliary heating units disposed along inner surfaces of the
graphene synthesis chamber 700, and may extend laterally in the
chamber case 710 in order to supply a gas including carbon into
auxiliary spaces formed along a top surface and a bottom surface of
the chamber case 710. In this case, a gas discharge unit (not
shown) faces the gas supply unit 702 and discharges remaining gases
left after graphene synthesis to the outside.
[0111] The gas supply unit 102 may supply not only a gas including
carbon but also an atmospheric gas into an inner space I.
Alternatively, a gas supply unit for supplying a gas including
carbon and a gas supply unit for supplying an atmospheric gas may
be separately provided, and the gas including carbon and the
atmospheric gas may be separately supplied into the chamber case
710.
[0112] Referring to FIG. 8, the main heating units 720 emit light
having a near-infrared wavelength band into an inner space defined
by the chamber case 710 that is a hexahedron. The main heating
units 720 may be disposed along a center and inner surfaces of the
chamber case 710. The light having the near-infrared wavelength
band emitted from the main heating units 720 disposed adjacent to
the center and the inner surfaces may mainly heat the substrates 10
and the auxiliary heating units 730 as described above. The light
having the near-infrared wavelength band may be directly emitted to
the substrates 10 and the auxiliary heating units 730 to uniformly
increase temperatures of the substrates 10 and the auxiliary
heating units 730 and help to rapidly reach a temperature needed to
synthesize graphene.
[0113] Alternatively, the main heating units 720 may emit not only
the light having the near-infrared wavelength band but also light
having at least one of a mid-infrared wavelength band and a visible
wavelength band. The light having the mid-infrared wavelength band
or the visible wavelength band may heat a gas including carbon
supplied into the chamber case 710.
[0114] Since the light having the near-infrared wavelength band
heats the substrates 10 and the auxiliary heating units 730 and the
light having the mid-infrared wavelength band and/or the visible
wavelength band heats the gas including carbon, a temperature of an
outer wall of the chamber case 710 may be maintained at a level
lower than temperatures of the substrates 10. That is, since only
the substrates 10 and surroundings of the substrates 10 are heated
without heating the entire graphene synthesis chamber 700, a
temperature needed to synthesize graphene may be controlled. Since
a time taken to increase a temperature to a temperature needed to
synthesize graphene, and then, reduce the temperature is reduced in
this configuration, graphene may be mass produced.
[0115] Meanwhile, when an inside of a chamber is heated by using an
inductor coil, since an inner space of the chamber needs to be
entirely heated, it takes a long time to reach a temperature needed
to synthesize graphene and it takes a long time to reduce the
temperature after graphene synthesis. However, the graphene
synthesis chamber 700 of FIG. 7 uses light having a near-infrared
wavelength band, a temperature may be easily controlled, the
substrate 10 may be heated to a temperature needed to rapidly
synthesize graphene without heating the entire inner space, and a
temperature may be uniformly increased irrespective of a position
of the substrate 10 as described above.
[0116] Also, since the chamber case 710 of the graphene synthesis
chamber 700 includes a plurality of surfaces in FIG. 7, more
graphene may be produced during the same time.
[0117] FIG. 9 is a graph illustrating a Raman spectrum of graphene
synthesized in the graphene synthesis chamber 200 of FIG. 4.
[0118] Referring to FIG. 9, it is found from a peak G and a peak 2D
that a single graphene layer is synthesized.
[0119] FIG. 10 is a cross-sectional view illustrating a graphene
synthesis chamber 1000 according to another exemplary embodiment.
FIG. 11 is a cross-sectional view illustrating a metal thin film 31
corresponding to a portion XI of FIG. 10. FIG. 12 is a
cross-sectional view illustrating graphene 32 formed on the metal
thin film 31 corresponding to a portion XII of FIG. 10. FIG. 13 is
a perspective view illustrating the metal thin film 31 introduced
through a metal thin film inlet/outlet unit 1150 corresponding to a
portion XIII of FIG. 10. FIG. 14 is a perspective view illustrating
the graphene 32 and the metal thin film 31 discharged through the
metal thin film inlet/outlet unit 1150 corresponding to a portion
XIV of FIG. 10.
[0120] Referring to FIG. 10, the graphene synthesis chamber 1000
includes a chamber case 1110 for defining a graphene synthesis
space, a gas supply unit 1120, a gas discharge unit 1130, a main
heating unit 1140, and a metal thin film inlet/outlet unit
1150.
[0121] An inner space of the chamber case 1110 includes a space S1
in which the graphene 32 (see FIG. 12) is synthesized in a
roll-to-roll manner on the metal thin film 31 (see FIG. 12). The
gas supply unit 1120 and the gas discharge unit 1130 may be
disposed in the chamber case 1110.
[0122] The gas supply unit 1120 supplies a gas including carbon
(not shown) into the chamber case 1110. The gas including carbon
which is a reactive gas for forming the graphene 32 may be at least
one selected from the group consisting of methane (CH.sub.4),
carbon monoxide (CO), ethane (C.sub.2H.sub.6), ethylene (CH.sub.2),
ethanol (C.sub.2H.sub.5), acetylene (C.sub.2H.sub.2), propane
(CH.sub.3CH.sub.2CH.sub.3), propylene (C.sub.3H.sub.6), butane
(C.sub.4H.sub.10), pentane (CH.sub.3(CH.sub.2).sub.3CH.sub.3),
pentene (C.sub.5H.sub.10), cyclopentadiene (C.sub.5H.sub.6), hexane
(C.sub.6H.sub.14), cyclohexane (C.sub.6H.sub.12), benzene
(C.sub.6H.sub.6), and toluene (C.sub.7H.sub.8). The gas including
carbon is divided into carbon atoms and hydrogen atoms at high
temperature.
[0123] Also, the gas supply unit 1120 may supply not only a gas
including carbon but also an atmospheric gas into the chamber case
1110. The atmospheric gas may include an inert gas such as helium
or argon, and a non-reactive gas such as hydrogen for maintaining a
surface of the metal thin film 31 clean.
[0124] Although only one gas supply unit 1120 is illustrated for
convenience, the present embodiment is not limited thereto. For
example, a plurality of the gas supply units 1120 may be provided.
In this case, an atmospheric gas and a gas including carbon may be
separately supplied into the chamber case 1110 through the
plurality of gas supply units 1120.
[0125] The gas discharge unit 1130 is disposed at a second side of
the graphene synthesis chamber 1000, and discharges remaining
gases, after being used to synthesize the graphene 32, to the
outside. Also, the gas discharge unit 1130 may reduce a pressure in
the chamber case 1110 by discharging air in the chamber case 1110
to the outside of the chamber case 1110. In this case, the pressure
in the chamber case 1110 may be reduced to about several hundred
torr to about 10.sup.-6 torr. Also, the gas discharge unit 1130 may
discharge gases, after being used to synthesize the graphene 32, to
the outside of the chamber case 1110.
[0126] Although only one gas discharge unit 1130 is illustrated for
convenience, the present embodiment is not limited thereto. For
example, a plurality of the gas discharge units 1130 may be
provided. In this case, a gas used to reduce a pressure in the
chamber case 1100 and a gas used to synthesize the graphene 32 may
be discharged to the outside of the chamber case 1100 through the
plurality of different gas discharge units 1130.
[0127] The main heating unit 1140 is disposed in the chamber case
1100. The main heating unit 1140 includes a plurality of lamps 1141
that emit radiant heat. The lamps 1041 may be halogen lamps. The
lamps 1141 may be surrounded by windows 1142, and the windows 1142
may protect the lamps 1141 and improve luminous efficiency.
[0128] A method of synthesizing the graphene 32 (see FIG. 12) on
the metal thin film 31 (see FIG. 11) which is a catalyst may
include a process of heating an atmospheric gas (hereinafter,
referred to as a preheating process), a process of heating a gas
including carbon or the metal thin film 31 at a high temperature of
at least about 800.degree. C. (hereinafter, referred to as a
heating process), and a process of reducing the temperature in
order to obtain graphene crystals (hereinafter, referred to as a
cooling process). In a conventional method, a CVD device has been
used. However, since the CVD device heats not only the metal thin
film 31 or a gas in the chamber case 1110 but also the entire
chamber case 1110 to appropriate temperatures, both a heating time
and a cooling time are long. However, since the main heating unit
1140 of FIG. 10 uses radiant heat, the main heating unit 1140 may
rapidly heat the metal thin film 31 or a gas in the chamber case
1110 to a desired temperature, and also reduce a cooling time.
[0129] Also, the main heating unit 1140 may emit not only light
having a near-infrared (NIR) wavelength band, but also light having
a mid-infrared (MIR) wavelength band and/or a visible (IR)
wavelength band. Accordingly, the light having the mid-infrared
wavelength band and/or the visible wavelength band which mainly
increase a temperature of a gas may be mainly used in the
preheating process, and the light having the near-infrared
wavelength band which increases a temperature of the metal thin
film 31 may be mainly used in the heating process. If the light
having the mid-infrared wavelength band and/or the light having the
near-infrared wavelength band are used in the preheating process,
since a temperature of an outer wall of the chamber case 1110 may
be maintained at relatively low, a temperature which is one of
important factors in mass producing the graphene 32 is reduced,
thereby improving productivity. Also, if the light having the
near-infrared wavelength band is used in the heating process, the
light having the near-infrared wavelength band is directly emitted
to the metal thin film 31, a temperature of the metal thin film 31
is uniformly increased, and it takes a short time to reach a
temperature needed to synthesize the graphene 32.
[0130] Auxiliary heating units 1145 may be disposed to face at
least one of a first surface and a second surface of the metal thin
film 31. Temperatures of the auxiliary heating units 1145 may
increase due to light having a near-infrared wavelength band
emitted from the main heating unit 1140. Accordingly, since the
auxiliary heating units 1145 trap heat generated around the metal
thin film 30, a temperature needed to synthesize the graphene 32
may be achieved more rapidly.
[0131] The graphene 32 is synthesized on the metal thin film 31 in
a roll-to-roll manner. A first roller R1 around which the metal
thin film 31 is wound before the graphene 32 is synthesized, and a
second roller R2 around which the metal thin film 31 is wound after
the graphene 32 is synthesized are disposed outside the chamber
case 1100.
[0132] FIG. 11 is a cross-sectional view illustrating the metal
thin film 31 disposed outside the chamber case 1110 before the
graphene 32 is synthesized. The metal thin film 31 may include at
least one metal selected from the group consisting of Ni, Co, Fe,
Pt, Au, Ag, Al, Cr, Cu, Mg, Mn, Mo, Rh, Si, Ta, Ti, W, U, V, Pd, Y,
and Zr. The metal thin film 31 before the graphene 32 is
synthesized is wound around the first roller R1 and is disposed
outside the chamber case 1110.
[0133] Although the metal thin film 31 is a single layer in FIG.
11, the present embodiment is not limited thereto. The metal thin
film 31 may further include a base layer formed of an inorganic
material such as Si, glass, GaN, or silica, a metal such as Ni, Cu,
or W, SiO.sub.2, Si.sub.3N.sub.4, SiON, SIOF, BN, HSQ, xerogel,
aero gel, poly naphthalene, a-CF, SiOC, MSQ, or black diamond,
which is soft enough to be used in a roll-to-roll manner.
[0134] FIG. 12 is a cross-sectional view illustrating a graphene
structure carried to the outside of the chamber case 1110 after the
graphene 32 is synthesized on the metal thin film 31. The metal
thin film 31 after the graphene 32 is synthesized is wound around
the second roller R2 and is disposed outside the chamber case
1110.
[0135] In order to form the graphene 32 on the metal thin film 31
in a roll-to-roll manner, a member for introducing the metal thin
film 31 disposed outside the chamber case 1110 into the chamber
case 110 and discharging the metal thin film 31 to the outside of
the chamber case 1110 after the graphene 32 is completely
synthesized is required. To this end, the graphene synthesis
chamber 1000 of FIG. 10 includes a metal thin film inlet/outlet
unit 1150 formed in the chamber case 1110.
[0136] The metal thin film inlet/outlet unit 1150 includes a metal
thin film inlet 1151 through which the metal thin film 31 is
introduced into the chamber case 1110 from the outside of the
chamber case 1110, and a metal thin film outlet 1152 which faces
the metal thin film inlet 1151 and through which the metal thin
film 31 on which the graphene 32 is completely synthesized is
discharged to the outside of the chamber case 1110.
[0137] It is preferable, but not necessary, that when the graphene
32 is synthesized, a step of increasing a temperature of an
atmospheric gas or a step of heating a gas including carbon to a
high temperature is performed in vacuum. However, when the graphene
32 is synthesized, if the first roller R1 and the second roller R2
are located outside the chamber case 1110, vacuum needs to be
temporarily removed in order for the metal thin film 31 to pass
through the chamber case 1110. To this end, the metal thin film
inlet 1151 and the metal thin film outlet 1152 respectively include
first and second gaps g1 and g2 (see FIGS. 13 and 14) that close
while the chamber case 1110 is maintained in vacuum and open while
the graphene 32 is synthesized such that the metal thin film 31
passes through the chamber case 1110, and first and second rotating
rollers 1151a, 1151b, 1152a, and 1152b that rotate as the metal
thin film 31 moves. According to an exemplary embodiment, only the
second gap g2 among the first and second gaps g1 and g2 may be open
while the graphene 32 is synthesized such that the metal thin film
31 passes through the chamber case 1110.
[0138] Referring to FIG. 13, the first gap g1 is formed at a side
of the chamber case 1110 such that the metal thin film 31 wound
around the first roller R1 is introduced into the chamber case 1110
to synthesize the graphene 32.
[0139] When the graphene 32 is synthesized, the first gap g1 should
be greater than at least a thickness d1 of the metal thin film 31.
Also, it is preferable, but not necessary, that in order to prevent
vacuum from being removed when the graphene 32 is synthesized, the
first gap g1 is substantially equal to the thickness d1 of the
metal thin film 31.
[0140] The first rotating rollers 1151a and 1151b are disposed at
both sides of the first gap g1 in order to smoothly move the metal
thin film 31 in a roll-to-roll manner.
[0141] The metal thin film inlet 1151 includes the first rotating
rollers 1151a and 1151b having a torque direction opposite to a
movement direction of the metal thin film 31. The first rotating
rollers 1151a and 1151b linearly contact the metal thin film 31,
thereby minimizing friction with the metal thin film 31 and
preventing damage to the metal thin film 31. Also, in order to
minimize damage to the metal thin film 31, a portion of the metal
thin film inlet 1151 contacting the metal thin film 31 may be
formed of a material having a hardness less than that of the metal
thin film 31.
[0142] Although the metal thin film inlet 1151 includes the first
rotating rollers 1151a and 1151b in FIG. 13, the present embodiment
is not limited thereto. For example, the metal thin film inlet 1151
may include a plurality of bearings instead of the first rotating
rollers 1151a and 1151b, or other various rotating units for
smoothly moving the metal thin film 31 and minimizing damage to the
metal thin film 31.
[0143] Although not shown in detail in FIG. 13, while the chamber
case 1110 needs to be maintained in vacuum, the first gap g1
closes. In this case, the first gap g1 may close without using an
additional unit. No gap may be formed by disposing an additional
buffer device between the first rotating rollers 1151a and 1151b,
or vacuum may be maintained by further disposing additional
opening/shutting devices at side surfaces of the first rotating
rollers 1151a and 1151b.
[0144] Referring to FIG. 14, the second gap g2 is formed at a side
of the chamber case 1110 such that the graphene structure 30
including the metal thin film 31 on which the graphene 32 is
completely synthesized is discharged to the outside of the chamber
case 1110. The graphene structure 30 is carried to the second
roller R2 disposed outside the chamber case 1110.
[0145] The second gap g2 should be greater than at least a sum of
the thickness d1 of the metal thin film 31 and a thickness d2 of
the graphene 32. Also, it is preferable, but not necessary, that in
order to prevent vacuum from being removed while the graphene 32 is
synthesized, the second gap g2 is substantially equal to the sum of
the thickness d1 of the metal thin film 31 and the thickness d2 of
the graphene 32.
[0146] The second rotating rollers 1152a and 1152b of the metal
thin film outlet 1152 are disposed at both sides of the second gap
g2 to smoothly move the graphene structure 30 in a roll-to-roll
manner. Although the metal thin film outlet 1152 includes the
second rotating rollers 1152a and 1152b, the present embodiment is
not limited thereto, and the metal thin film outlet 1152 may be
modified in various ways. Also, in order to minimize damage to the
metal thin film 31 and the graphene 32, a portion of the metal thin
film outlet 1152 contacting the metal thin film 31 may be formed of
a material having a hardness less than that of the metal thin film
31.
[0147] When the graphene 32 is synthesized, in order to prevent
vacuum from being removed due to the first and second gaps g1 and
g2, loadlock chambers 1160 may be disposed outside the chamber case
1110 with the first and second gaps g1 and g2 therebetween. The
first roller R1 and the second roller R2 may be disposed in the
loadlock chambers 1160 disposed at both sides of the chamber case
1110.
[0148] Since it is difficult to maintain the tension of a metal
thin film at a high temperature because a related art graphene
synthesis chamber using CVD is entirely heated, it is also
difficult to synthesize graphene in a roll-to-roll manner. However,
in a heating method using radiant heat of lamps as in the present
embodiment, since a temperature is high but a time taken for the
lamps to emit light is reduced, the tension of a metal thin film
may be maintained. Accordingly, since graphene may be synthesized
in a roll-to-roll manner, the graphene may be mass produced.
[0149] A graphene synthesis chamber 1500 according to another
exemplary embodiment will be explained with reference to FIG. 15.
The same elements are denoted by the same reference numerals and
the following explanation will be made by focusing on the
differences between the embodiments.
[0150] FIG. 15 is a cross-sectional view illustrating the graphene
synthesis chamber case 1500 according to another exemplary
embodiment. Referring to FIG. 15, like in the previous embodiments,
the graphene synthesis chamber 1500 includes the chamber case 1110
for defining a graphene synthesis space, the gas supply unit 1120,
the gas discharge unit 1130, the main heating unit 1140, and the
metal thin film inlet/outlet unit 1150, and also includes a barrier
wall 1170 for dividing an inner space of the chamber case 1110.
[0151] The inner space of the chamber case 1110 may be divided by
the barrier wall 1170 into a space S21 in which an atmospheric gas
is heated and a space S22 in which the metal thin film 31 and a gas
including carbon are heated. The present embodiment is not limited
thereto, and a plurality of the barrier walls 1170 may be provided
and a space for performing another function may be further
provided. Also, only one process may not be performed in one space.
For example, in the space S22 in which the metal thin film 31 and
the gas including carbon are heated, not only "a heating process"
may be performed but also "a cooling process" for crystallizing the
graphene 32 may be performed by turning on or off the main heating
unit 1140.
[0152] The barrier wall 1170 may further include an
opening/shutting portion 1171 for connecting or separating the
spaces S21 and S22.
[0153] The space S21 in which the atmospheric gas is heated and the
space S22 in which the metal thin film 31 and the gas including
carbon are heated may use light having different wavelength bands
from among light emitted from the main heating unit 1140. For
example, the space S21 in which the atmospheric gas is heated may
increase a temperature of the atmospheric gas by mainly using light
having a mid-infrared wavelength band and/or a visible wavelength
band emitted from the main heating unit 1140, and the space S22 in
which the metal thin film 31 and the gas including carbon are
heated may heat the metal thin film 31 by mainly using light having
a near-infrared wavelength band emitted from the main heating unit
1140 and heat the gas including carbon by using light having a
mid-infrared wavelength band and/or a visible wavelength band
emitted from the main heating unit 1140.
[0154] That is, since "a preheating process" and "a heating
process" are performed in different spaces and temperatures needed
for the preheating process and the heating process are differently
set, an overall time of graphene synthesis may be reduced.
[0155] In the present embodiment, the auxiliary heating units 1145
may also be disposed in the space S22 in which the metal thin film
31 and the gas including carbon are heated.
[0156] A graphene synthesis chamber 1600 according to another
exemplary embodiment will be explained with reference to FIGS. 16
through 18. The same elements are denoted by the same reference
numerals, and the following explanation will be made by focusing on
the differences between the embodiments.
[0157] FIG. 16 is a cross-sectional view illustrating the graphene
synthesis chamber 1600 according to another exemplary embodiment.
FIG. 17 is a cross-sectional view illustrating the metal thin film
31 corresponding to a portion XVII of FIG. 16. FIG. 18 is a
cross-sectional view illustrating the graphene 32 formed on the
metal thin film 31 corresponding to a portion XVIII of FIG. 16.
[0158] Referring to FIGS. 16 through 18, the graphene synthesis
chamber 1600 includes the chamber case 1110 for defining a graphene
synthesis space, the gas supply unit 1120, the gas discharge unit
1130, and the main heating unit 1140, and also includes metal thin
film protecting units 1180 disposed in the chamber case 1110.
[0159] The graphene 32 is synthesized on the metal thin film 31 in
a roll-to-roll manner. The first roller R1 around which the metal
thin film 31 is wound before the graphene 32 is synthesized and the
second roller R2 around which the metal thin film 31 is wound after
the graphene 32 is synthesized are disposed in the chamber case
1110.
[0160] Since the metal thin film 31 wound around the first roller
R1 and the second roller R2 is disposed in the chamber case 1110,
the metal thin film 31 may be damaged due to a gas heated at high
temperature when the graphene 32 is synthesized. Accordingly, in
order to protect portions of the metal thin film 31 wound around
the first and second rollers R1 and R2 and moving in the chamber
case 1110 in a roll-to-roll manner when the graphene 32 is
synthesized, the metal thin film protecting units 1180 are provided
to cover the portions of the metal thin film 31 wound around the
first and second rollers R1 and R2.
[0161] The metal thin film protecting units 1180 may include
inlet/outlets 1181 through which the metal thin film 31 (see FIG.
17) wound around the first roller R1 is discharged to a synthesis
space S3 and through which the metal thin film 31 is introduced to
the second roller R2 from the synthesis space S3 after the graphene
32 (see FIG. 18) is synthesized.
[0162] If the metal thin film protecting units 1180 are evaporated
at a temperature lower than a temperature at which the graphene 32
is synthesized, the metal thin film protecting units 1180 may act
as impurities when the graphene 32 is synthesized. Accordingly, it
is preferable, but not necessary, that the metal thin film
protecting units 1180 include a material that evaporates at a
temperature higher than the temperature at which the graphene 32 is
synthesized.
[0163] Accordingly, since the metal thin film 31 of the graphene
synthesis chamber 1600 of FIG. 16 is disposed only in the chamber
case 1110 unlike in the previous embodiments, vacuum may be
maintained even while the graphene 32 is synthesized and thus the
graphene 32 may be mass produced more stably.
[0164] In this embodiment, the auxiliary heating units 1145 may
also be disposed in the space S22 in which the metal thin film 31
and the gas including carbon are heated.
[0165] A graphene synthesis chamber 1900 according to another
exemplary embodiment will be explained with reference to FIG. 19.
The same elements are denoted by the same reference numerals, and
the following explanation will be made by focusing on a difference
from the graphene synthesis chamber 1600 of FIG. 16.
[0166] FIG. 19 is a cross-sectional view illustrating the graphene
synthesis chamber 1900 according to another exemplary embodiment.
Referring to FIG. 19, like in the previous embodiments, the
graphene synthesis chamber 1900 includes the chamber case 1110 for
defining a graphene synthesis space, the gas supply unit 1120, the
gas discharge unit 1130, the main heating unit 1140, and the metal
thin film protecting units 1180 disposed in the chamber case 1110,
and also includes a barrier wall 1190 for dividing an inner space
of the chamber case 1110.
[0167] The inner space of the chamber case 1110 is divided by the
barrier wall 1190 into a space S41 in which an atmospheric gas is
heated, and a space S42 in which the metal thin film 31 and a gas
including carbon are heated. The present embodiment is not limited
thereto, and a plurality of the barrier walls 1190 may be provided
and a space for performing another function may be further
provided. The barrier wall 1190 may further include an
opening/shutting portion 1191 for connecting or separating the
spaces S41 and S42.
[0168] The metal thin film protecting units 1180 are disposed in
the space S42 in which the metal thin film 31 and the gas including
carbon are heated to synthesize the graphene 32 in a roll-to-roll
manner.
[0169] The space S41 which the atmospheric gas is heated and the
space S42 in which the metal thin film 31 and the gas including
carbon are heated may use light having different wavelength bands
from among light emitted from the main heating unit 1140. For
example, the space S41 in which the atmospheric gas is heated may
increase a temperature of the atmospheric gas by mainly using light
having a mid-infrared wavelength band and/or a visible wavelength
band of the main heating unit 1140, and the space S42 in which the
metal thin film 31 and the gas including carbon are heated may heat
the metal thin film 31 by mainly using light having a near-infrared
wavelength band of the main heating unit 1140 and heat a
temperature of the gas including carbon to a temperature needed to
synthesize the graphene 32 by mainly using light having a
mid-infrared wavelength band and/or a visible wavelength band of
the main heating unit 1140. That is, "a preheating process" and "a
heating process" may be performed in different spaces. Since "the
preheating process" mainly uses light having a mid-infrared
wavelength band or a visible wavelength band, a temperature of the
atmospheric gas may rapidly reach an appropriate temperature. Since
"the heating process" mainly uses light having a near-infrared
wavelength band, temperatures of the metal thin film 31 and the gas
including carbon may rapidly reach appropriate temperatures.
[0170] Accordingly, since the barrier wall 1190 is provided in the
chamber case 1110 and different processes are performed in
different spaces by dividing an inner space of the graphene
synthesis chamber 1900, an overall time of graphene synthesis may
be reduced. Also, since the metal thin film 31 is disposed only in
the chamber case 1110, and thus, vacuum may be maintained even
while the graphene 32 is synthesized, the graphene 32 may be mass
produced more stably.
[0171] Even in the present embodiment, the auxiliary heating units
1145 may be disposed in the space S22 in which the metal thin film
31 and the gas including carbon are heated.
[0172] As described above, according to the one or more exemplary
embodiments, since light having a near-infrared wavelength band is
used, a temperature needed to synthesize graphene may be rapidly
achieved and a substrate may be uniformly heated.
[0173] Also, since auxiliary heating units are provided, a sharp
increase in temperature may be prevented, the loss of radiant
energy may be minimized, a heating time may be reduced, and
graphene synthesis efficiency may be improved.
[0174] In addition, since graphene may be synthesized in a
roll-to-roll manner, the graphene may be mass produced.
[0175] While the inventive concept has been particularly shown and
described with reference to exemplary embodiments thereof, it will
be understood by those of ordinary skill in the art that various
changes in form and details may be made therein without departing
from the spirit and scope of the inventive concept as defined by
the following claims.
* * * * *