U.S. patent application number 14/928957 was filed with the patent office on 2016-05-05 for graphene structure having nanobubbles and method of fabricating the same.
The applicant listed for this patent is Samsung Electronics Co., Ltd.. Invention is credited to Hyowon KIM, Wonhee KO, Jiyeon KU.
Application Number | 20160122189 14/928957 |
Document ID | / |
Family ID | 55851868 |
Filed Date | 2016-05-05 |
United States Patent
Application |
20160122189 |
Kind Code |
A1 |
KU; Jiyeon ; et al. |
May 5, 2016 |
GRAPHENE STRUCTURE HAVING NANOBUBBLES AND METHOD OF FABRICATING THE
SAME
Abstract
Example embodiments relate to graphene structures having
nanobubbles, and/or to a method of manufacturing the graphene
structure. The graphene structure includes a substrate and a
graphene layer on the substrate, the graphene layer having a
plurality of convex portions. One or more of the plurality of
convex portions has a hollow structure, and the graphene layer has
a band gap that is due to the plurality of convex portions. A noble
gas is included between the substrate and the convex portions.
Inventors: |
KU; Jiyeon; (Suwon-si,
KR) ; KO; Wonhee; (Seoul, KR) ; KIM;
Hyowon; (Seongnam-si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Samsung Electronics Co., Ltd. |
Suwon-si |
|
KR |
|
|
Family ID: |
55851868 |
Appl. No.: |
14/928957 |
Filed: |
October 30, 2015 |
Current U.S.
Class: |
428/166 ;
204/192.25; 427/585 |
Current CPC
Class: |
C23C 16/26 20130101;
H01L 21/02433 20130101; H01L 21/02422 20130101; H01L 21/02664
20130101; H01L 21/02527 20130101; C01B 2204/22 20130101; C01B
32/194 20170801; H01L 21/02587 20130101; H01L 21/02425 20130101;
H01L 21/0262 20130101; C01B 2204/02 20130101 |
International
Class: |
C01B 31/04 20060101
C01B031/04; B05D 1/00 20060101 B05D001/00; C23C 14/34 20060101
C23C014/34 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 31, 2014 |
KR |
10-2014-0150629 |
Claims
1. A graphene structure comprising: a substrate; and a graphene
layer on the substrate, the graphene layer having a plurality of
convex portions, wherein one or more of the plurality of convex
portions has a hollow structure, and the graphene layer has a band
gap due to the plurality of convex portions.
2. The graphene structure of claim 1, wherein the graphene layer is
substantially a mono layer.
3. The graphene structure of claim 1, wherein one or more of the
plurality of convex portions has a diameter in a range from about 2
nm to about 6 nm, and a height in a range from about 0.15 nm to
about 1 nm.
4. The graphene structure of claim 1, wherein the substrate
comprises a catalyst metal configured to grow the graphene
layer.
5. The graphene structure of claim 1, further comprising a noble
gas intercalated between the substrate and the plurality of convex
portions.
6. The graphene structure of claim 5, wherein the noble gas
comprises at least one of argon (Ar) ion gas, helium (He) ion gas,
neon (Ne) ion gas, krypton (Kr) ion gas, xenon (Xe) ion gas, and
radon (Rn) ion gas.
7. The graphene structure of claim 6, wherein the noble gas is
Ar.
8. A method of manufacturing a graphene structure, the method
comprising: preparing a graphene layer on a substrate; and forming
a plurality of convex portions on the graphene layer by irradiating
a noble gas onto the graphene layer.
9. The method of claim 8, wherein the preparing of the graphene
layer comprises: preparing a catalyst substrate; and growing the
graphene layer on the substrate by supplying a carbon source gas on
the catalyst substrate.
10. The method of claim 8, wherein the preparing of the graphene
layer comprises transferring the graphene layer on the
substrate.
11. The method of claim 8, wherein the irradiating the noble gas
comprises sputtering the noble gas.
12. The method of claim 8, wherein the noble gas comprises at least
one of Ar ion gas, He ion gas, Ne ion gas, Kr ion gas, Xe ion gas,
and Rn ion gas.
13. The method of claim 12, wherein the noble gas is Ar gas.
14. The method of claim 11, wherein the sputtering forms at least
one noble gas between the substrate and each of the plurality of
convex portions.
15. The method of claim 8, wherein each of the plurality of convex
portions has a diameter in a range from about 2 nm to about 6 nm,
and a height in a range from about 0.15 nm to about 1 nm.
Description
RELATED APPLICATION
[0001] This application claims the benefit of priority from Korean
Patent Application No. 10-2014-0150629, filed on Oct. 31, 2014, in
the Korean Intellectual Property Office, the disclosure of which is
incorporated herein in its entirety by reference.
BACKGROUND
[0002] 1. Field
[0003] Example embodiments relate to graphene structures having
nanobubbles and/or methods of fabricating the graphene
structures.
[0004] 2. Description of the Related Art
[0005] Graphene having a 2-dimensional hexagonal carbon structure
is a new material that can replace semiconductor. The graphene is
typically a zero gap semiconductor. However, a graphene nanoribbon
(GNR) having a width of 10 nm or less may have a band gap due to
size effect, and accordingly, a field effect transistor that can be
operated at room temperature can be manufactured by using GNR.
[0006] However, when the GNR is manufactured, an ON/OFF ratio of
graphene is improved but mobility may be reduced due to disordered
edges, and on-current may be small. As a solution to these
problems, a band gap may be formed by applying a field effect in a
vertical direction to a bi-layered graphene. However, this method
may not be suitable for growing graphene having a uniform double
structure, and may be difficult for practical use due to random
domain.
SUMMARY
[0007] Example embodiments relate to graphene structures that form
a band gap by using graphene having nanobubbles instead of graphene
nanoribbon (GNR).
[0008] Example embodiments relate to methods of manufacturing the
graphene structures.
[0009] Additional example embodiments will be set forth in part in
the description which follows and, in part, will be apparent from
the description, or may be learned by practice of the example
embodiments.
[0010] According to an example embodiment, a graphene structure
includes a substrate and a graphene layer on the substrate, the
graphene layer having a plurality of convex portions, wherein each
of the plurality of convex portions has a hollow structure, and the
graphene layer has a band gap due to the convex portions.
[0011] The graphene layer may be substantially a mono layer.
[0012] The convex portions may have a diameter in a range from
about 2 nm to about 6 nm, and a height in a range of about 0.15 nm
to about 1 nm.
[0013] The substrate may be formed of or include a catalyst metal
that may be used for growing the graphene layer.
[0014] The graphene structure may include a noble gas between the
substrate and the convex portions.
[0015] The noble gas may include argon (Ar) ion gas, helium (He)
ion gas, neon (Ne) ion gas, krypton (Kr) ion gas, xenon (Xe) ion
gas, or radon (Rn) ion gas.
[0016] According to an example embodiment, a method of
manufacturing a graphene structure includes preparing a graphene
layer on a substrate and forming a plurality of convex portions on
the graphene layer by irradiating a noble gas onto the graphene
layer.
[0017] Preparing the graphene layer may include preparing a
catalyst substrate and growing the graphene layer on the substrate
by supplying a carbon source gas on the catalyst substrate.
[0018] Preparing the graphene layer may include transferring the
graphene layer on the substrate.
[0019] Irradiating a noble gas may be or include sputtering the
noble gas.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] These and/or other example embodiments will become apparent
and more readily appreciated from the following description, taken
in conjunction with the accompanying drawings in which:
[0021] FIG. 1 is a schematic cross-sectional view of a graphene
structure having nanobubbles, according to at least one example
embodiment;
[0022] FIG. 2 is a photograph of a scanning tunneling microscope
(STM) showing a graphene structure having nanobubbles, according to
at least one example embodiment;
[0023] FIG. 3 is a graph illustrating a size of nanobubbles in
which a single Ar ion is formed;
[0024] FIG. 4 is a graph showing a differential conductance of
nanobubbles;
[0025] FIG. 5 is an STM photograph showing a graphene structure
having a plurality of nanobubbles, according to at least one
example embodiment; and
[0026] FIG. 6 is a graph showing sizes of nanobubbles
DETAILED DESCRIPTION
[0027] Reference will now be made in detail to example embodiments
illustrated in the accompanying drawings. In the drawings, the
thicknesses of layers and regions are exaggerated for clarity. The
example embodiments are capable of various modifications and may be
embodied in many different forms. Like reference numerals in the
drawings denote like elements throughout the specification, and
thus their description will be omitted. In the drawing figures, the
dimensions of layers and regions may be exaggerated for clarity of
illustration. Like reference numerals refer to like elements
throughout. The same reference numbers indicate the same components
throughout the specification.
[0028] It will be understood that when an element is referred to as
being "on," "connected" or "coupled" to another element, it can be
directly on, connected or coupled to the other element or
intervening elements may be present. In contrast, when an element
is referred to as being "directly on," "directly connected" or
"directly coupled" to another element, there are no intervening
elements present. As used herein the term "and/or" includes any and
all combinations of one or more of the associated listed items.
Further, it will be understood that when a layer is referred to as
being "under" another layer, it can be directly under or one or
more intervening layers may also be present. In addition, it will
also be understood that when a layer is referred to as being
"between" two layers, it can be the only layer between the two
layers, or one or more intervening layers may also be present.
[0029] It will be understood that, although the terms "first",
"second", etc. may be used herein to describe various elements,
components, regions, layers and/or sections, these elements,
components, regions, layers and/or sections should not be limited
by these terms. These terms are only used to distinguish one
element, component, region, layer or section from another element,
component, region, layer or section. Thus, a first element,
component, region, layer or section discussed below could be termed
a second element, component, region, layer or section without
departing from the teachings of example embodiments.
[0030] Spatially relative terms, such as "beneath," "below,"
"lower," "above," "upper" and the like, may be used herein for ease
of description to describe one element or feature's relationship to
another element(s) or feature(s) as illustrated in the figures. It
will be understood that the spatially relative terms are intended
to encompass different orientations of the device in use or
operation in addition to the orientation depicted in the figures.
For example, if the device in the figures is turned over, elements
described as "below" or "beneath" other elements or features would
then be oriented "above" the other elements or features. Thus, the
example term "below" can encompass both an orientation of above and
below. The device may be otherwise oriented (rotated 90 degrees or
at other orientations) and the spatially relative descriptors used
herein interpreted accordingly.
[0031] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
example embodiments. 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," when
used in this specification, specify the presence of stated
features, integers, steps, operations, elements, and/or components,
but do not preclude the presence or addition of one or more other
features, integers, steps, operations, elements, components, and/or
groups thereof.
[0032] Example embodiments are described herein with reference to
cross-sectional illustrations that are schematic illustrations of
idealized embodiments (and intermediate structures) of example
embodiments. As such, variations from the shapes of the
illustrations as a result, for example, of manufacturing techniques
and/or tolerances, are to be expected. Thus, example embodiments
should not be construed as limited to the particular shapes of
regions illustrated herein but are to include deviations in shapes
that result, for example, from manufacturing. For example, an
implanted region illustrated as a rectangle will, typically, have
rounded or curved features and/or a gradient of implant
concentration at its edges rather than a binary change from
implanted to non-implanted region. Likewise, a buried region formed
by implantation may result in some implantation in the region
between the buried region and the surface through which the
implantation takes place. Thus, the regions illustrated in the
figures are schematic in nature and their shapes are not intended
to illustrate the actual shape of a region of a device and are not
intended to limit the scope of example embodiments.
[0033] Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which example
embodiments belong. It will be further understood that terms, such
as those defined in commonly-used dictionaries, should be
interpreted as having a meaning that is consistent with their
meaning in the context of the relevant art and will not be
interpreted in an idealized or overly formal sense unless expressly
so defined herein. As used herein, expressions such as "at least
one of," when preceding a list of elements, modify the entire list
of elements and do not modify the individual elements of the
list.
[0034] FIG. 1 is a schematic cross-sectional view of a graphene
structure 100 having nanobubbles, according to an example
embodiment.
[0035] Referring to FIG. 1, the graphene structure 100 having
nanobubbles 122 includes a graphene layer 120 formed on a substrate
110. The substrate 110 may be formed of or include Pt having a
(111) surface. The graphene layer 120 may be formed by supplying a
carbon source gas on a Pt substrate as a catalyst.
[0036] However, the example embodiment is not limited thereto. The
substrate 110 may be an insulating substrate. For example, the
substrate 110 may include a silicon substrate and a silicon oxide
layer on the silicon substrate. When an insulating substrate is
used as the substrate 110, the graphene layer 120 may be disposed
on the substrate 110 by transferring the graphene layer 120.
[0037] The graphene layer 120 may include a plurality of convex
portions 122. In FIG. 1, for convenience, two convex portions 122
are depicted. Each of the convex portions 122 may have a nano size.
Hereinafter, the convex portions 122 are referred to as nanobubbles
122. The nanobubbles 122 may be formed by irradiating a noble gas,
such as Ar ions, on the graphene layer 120. The noble gas may
include Ar ions, Ar atoms, etc. The irradiation of Ar ions may be
performed via, for example, a sputtering method.
[0038] Ar ions having a predetermined energy are intercalated
between the substrate 110 and the graphene layer 120 by penetrating
through the graphene layer 120. Regions of the graphene layer 120
where the Ar ions are intercalated form the convex portions 122
(nanobubbles 122) because of the volume of Ar ions. Ar ions in the
nanobubbles 122 may exist as Ar atoms by doping the graphene layer
120.
[0039] At least one Ar ion may exist in each of the nanobubbles
122. The Ar ion may dope the graphene layer 120 and may be
transformed into an Ar atom as a result.
[0040] The example embodiments are not limited thereto. For
example, instead of Ar ion gas, helium (He) ion gas, neon (Ne) ion
gas, krypton (Kr) ion gas, xenon (Xe) ion gas, radon (Rn) ion gas
may be used.
[0041] FIG. 2 is a photograph of a scanning tunneling microscope
(STM) photograph showing a graphene structure having nanobubbles
122 according to an example embodiment. The STM photograph has a
dimension of 3.0 nm.times.3.0 nm.
[0042] As shown in FIG. 2, a convex portion (the nanobubble 122)
having a nano size protrudes upward, which is a z direction as
illustrated in the figure.
[0043] FIG. 3 is a graph showing a size of a nanobubble 122 in
which a single Ar ion is intercalated. FIG. 3 illustrated this
result via a density functional theory (DFT) calculation.
[0044] Referring to FIG. 3, the nanobubble having a single Ar ion
has a diameter of approximately 2 nm and a height of approximately
0.15 nm.
[0045] FIG. 4 is a graph showing a differential conductance of the
nanobubble. The differential conductance is measured via scanning
tunneling spectroscopy (STS).
[0046] Referring to FIG. 4, the differential conductance of the
nanobubble is changed according to a bias voltage. As a result, the
nanobubble has a peak near a Dirac point, and has a similar
characteristic to a band gap.
[0047] Hereinafter, a method of manufacturing the graphene
structure 100 according to another example embodiment will be
described with reference to FIG. 1.
[0048] First, a substrate 110 is prepared. In the example
embodiment, a Pt substrate having a (111) surface is used as the
substrate 110. However, the example embodiment is not limited
thereto. For example, an insulating substrate in which a silicon
oxide layer is formed on a silicon substrate may be used. Also, a
plastic substrate may be used.
[0049] When the substrate 110 formed of or including Pt which is a
catalyst material is used, graphene is grown by supplying a carbon
source gas, for example, an ethylene gas onto the substrate 110.
The graphene layer 120 may be grown at a temperature of
approximately 400.degree. C. for approximately 10 minutes. Thus,
the graphene layer 120 may be formed on the substrate 110. The
graphene layer 120 may have a structure of one layer or more
according to the amount of the carbon source gas that is supplied
onto the substrate 110 and the supplying time. In the example
embodiment, the graphene layer 120 has one layer.
[0050] However, the example embodiment is not limited thereto. The
graphene layer 120 may be formed by transferring the graphene layer
120 on the substrate 110.
[0051] According to at least one example embodiment, Ar ions are
irradiated onto the graphene layer 120. The Ar irradiation may be
performed via, for example, a sputtering method. Ar ions may be
supplied with a power of 500 eV and a current of 1 .mu.A. Ar ions
are intercalated between the substrate 110 and the graphene layer
120 by penetrating through the graphene layer 120. As a result, a
plurality of convex portions (nanobubbles 122) are formed the
graphene layer 120. Ar ions in the nanobubbles 122 may dope the
graphene layer 120, and as a result may become Ar atoms.
[0052] In the example embodiment, Ar ions are used as a noble gas.
However, the noble gas according to the example embodiment is not
limited thereto. For example, instead of Ar ion gas, helium (He)
ion gas, neon (Ne) ion gas, krypton (Kr) ion gas, xenon (Xe) ion
gas, and radon (Rn) ion gas or another noble gas may be used as the
noble gas.
[0053] FIG. 5 is an STM picture showing a graphene structure having
a plurality of nanobubbles, according to another example
embodiment. The example graphene structure of FIG. 5 has a
dimension of 25 nm.times.25 nm.
[0054] Referring to FIG. 5, two graphene islands may be formed on a
(111) Pt substrate. A plurality of nanobubbles may be formed in
each island. At least one Ar ion may be present between each of the
nanobubbles and the substrate.
[0055] FIG. 6 is a graph showing sizes of nanobubbles of FIG. 5.
According to at least one example embodiment, nanobubbles have a
diameter in a range from about 2 nm to about 6 nm and a height in a
range from about 0.15 nm to about 1 nm. The size of nanobubbles may
vary according to the number of Ar ions (or Ar atoms) that exist in
the nanobubbles. As the number of nanobubbles increases, the size
of the nanobubbles increases.
[0056] In the graphene structure having nanobubbles according to an
example embodiment, Ar ions penetrate through the graphene layer,
and thus, a nanobubble structure is formed as a result.
Accordingly, the graphene layer having the nanobubbles may have a
band gap. In the example embodiment, since a band gap is formed in
graphene due to a size effect without using GNR as in the
conventional art, the graphene may be used in any graphene device
that requires graphene having a band gap.
[0057] While one or more example embodiments have been described
with reference to the figures, 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 as
defined by the following claims.
* * * * *