carbon nanostructures (i)
TRANSCRIPT
Carbon Nanostructures (I)
Ming-Show Wong
May, 2013
(All the contents in this file are solely for educational purpose)
Name: carbon
Symbol: C
Atomic number: 6
Atomic weight: 12.0107 (8) g r
Group in periodic table: 14
Period in periodic table: 2
Block in periodic table: p-block
CAS registry ID: 7440-44-0
Standard state: solid at 298 K
Colour: graphite is black, diamond is colourless
http://www.webelements.com/webelements/elements/text/C/key.html
Carbon Nanostructures In 1980 we knew of only three forms of carbon, namely diamond, graphite and amorphous.
If diamond sheets could be made cheaply all objects that
need to be hard and indestructible would be made from
diamond.
Until 1964 it was generally believed that no other carbon bond angles were possible
in hydrocarbons. But two more carbon bond were synthesized successfully.
1964
Phil Eaton
University of Chicago
1983
L. Paquette
Ohio State University
Cubane C8H8 Dodecahedron C20H20
New Carbon Structure
Types of Hybridization Digonal sp Trigonal sp2 Tetrahedral sp3
Orbitals used for bond s, px s, px, py s, px, py, pz
Example Acetylene C2H2 Ethylene C2H4 Methane CH4
Value of l 1 21/2 31/2
Bond angle 180o 120o 109o 28’
SP Hybridization
ps lWavefunction
Diamond lattice Graphite lattice
http://www.bris.ac.uk/Depts/Chemistry/MOTM/diamond/diamond.htm
http://www.seed.slb.com/en/watch/fullerenes/begin.htm
C C
C C C
C
C
C
C C C C C C
C C C C C C C
CC
C
C C
C
C C C C C C C C C
C
C
C
C C
C
CC
C
C
C
CC
CC
CC
C
C
Small Carbon Clusters
For small clusters of N < 30, they are
linear structure when N is odd, and
closed structure when N is even.
Discovery of C60
1. There is optical extinction at 220 nm (5.6 eV) of light coming from stars.
2. Donald Huffman (U. of Arizona) and Wolfgang Kratschmer (Max Planck
Institute of Nuclear Physics in Heidelberg) simulate the “graphite” production
in the laboratory by striking an arc between two graphite electrodes in helium
environment. They found the spectral lines in IR (Raman) absorption spectrum
that does not originate from graphite. Using isotope methods the IR lines shift
follows what was postulated as C60 molecule.
3. Harlod Kroto (U. of Sussex in England) found the presence of carbon
chains in “red giant” in outer space and would like to reproduce them in the
laboratory. So he contacted Professor Smalley.
Richard Smalley (Rice Univ. in Houston) use high-powered pulsed laser to
produce carbon vapor. One kind of the clusters from condensation of vapor by
helium swept has mass corresponding to C60 measured by mass spectrometer.
Mass Spectrum of Carbon Clusters By laser ablation and mass spectrometer
The Nobel Prize in Chemistry 1996
"for their discovery of fullerenes"
Robert F. Curl Jr.
Sir Harold W. Kroto
Richard E. Smalley
1/3 of the prize 1/3 of the prize 1/3 of the prize
USA United Kingdom USA
Rice University Houston, TX, USA
University of Sussex Brighton, United Kingdom
Rice University Houston, TX, USA
b. 1933 b. 1939 b. 1943
http://www.cochem2.tutkie.tut.ac.jp/Fuller/fsl/higher.html
12 pentagonal (5 sided) and 20 hexagonal (6 sided)
R. Buckminister Fuller, architect and inventer who designed the geodesic
dome resemble this structure at the 1965 New York World's Fair .
C60 - Buckministerfullerene
http://sbchem.sunysb.edu/msl/fullerene.html
Unit cell of C60 Crystal – An FCC
Single crystal is prepared by slow evaporation of solution of C60 in benzene.
Van der Waals force.
1 nm 1 nm
Endohedral and Exahedral
N @ C60
http://www.organik.uni-erlangen.de/hirsch/endo_chem.html
Superconductivity of C60
F. Hebard at Bell Labs doped C60 with potassium (K3C60) in 1991.
• Placed C60 and potassium in evacuated tubes and heated to 400oC.
• A reduction of the magnetic susceptibility c of the sample to c = -1
(MKS system) at 18K and below.
Superconducting transition temperature increases with lattice parameter of
A3C60 for various alkali dopants A.
http://buckminster.physics.sunysb.edu/images/compo_large.jpg
K3C60: 2 tetrahedral and 1 octahedral per C60
C60 C70 C76 C78
http://www.susx.ac.uk/Users/kroto/FullereneCentre/gallery/main.html
The different fullerenes obey to the Euler theorem for polyhedra: f + v = e + 2
where: f is the number of faces, v the number of vertices and e the number of edges
http://www.cm.utexas.edu/academic/courses/Fall1998/CH380L/bp.html
Other Fullerenes
Synthesis of other Fullerenes
C20 by gas-phase dissociation of C20HBr13.
C36H4 by pulsed laser ablation of graphite.
Dodecahedron
V = 20
E = 30
F = 12
20 - 30 + 12 = 2
• Pure C60 are only semi-conducting. Resistivity = 108 W-cm at
25oC.
• Resistivity of MnC60 reduces as n reduce to 3, and increases as n
increase to 6, i.e., M3C60 has the lowest resistivity while M6C60 is
an insulator.
• M3C60 is also an superconductor with transition temperature = -
243oC for M = Rb.
Resistivity of C60
• Polymerization of carbon cages into a rigid framework
• Energy for escaping the carbon cage is 6 eV.
• “Metal-semiconductor” junction may be formed
Metals Semiconductor
Heterojunction Formation by molecule Polymerization
Optimized structures of Si20Cn clusters.
Novel Silicon-Carbon Fullerene-Like Cages
http://arxiv.org/ftp/cond-mat/papers/0309/0309443.pdf
Tungsten Trapped in a Silicon Cage Cluster
Reported by: H. Hiura et al, Physical Review Letters, 26 February 2001
Types of Nanotubes
http://fy.chalmers.se/f3a/Fullerenes/Nanotubes/projects/SWNTTEMimage.html
SWNT (Unaligned)
http://www.chem.ox.ac.uk/icl/catcentre/Ag_swnt.pdf
http://eoeml-web.gtri.gatech.edu/jready/cntubes.shtml
http://www.ifw-dresden.de/forsch/jb2000/23_26highlight5.pdf
SWNT (Bundles of Ropes)
Micrographs of MWNT, from
above: SEM-image of
MWNT with diameter of 10 –
40nm and TEM-image of
MWNT with hollow core and
Fe catalyst.
HRTEM micrograph of MWNT-
tubular; the graphite planes are
exactly arranged parallel to the
tube axis.
MWNT
http://www.ifw-dresden.de/forsch/jb2000/23_26highlight5.pdf
The structure of carbon nanotubes is determined by the Wrapping Vector:
C=na1+ma2, where n and m are integers.
http://www.rpi.edu/dept/materials/COURSES/NANO/ward/page2.html
CNT Chiralty
•n-m is divisible by three, metallic
•n-m not divisible by three, semiconducting, with a gap of ~0.5 eV.
nanotubes could be either metallic or semiconducting, depending on the 1st
Brillouin Zone determined by using a 1-D tight binding energy
approximation.
Two thirds are semiconductor and one-third metallic.
Metallic tubes have armchair structure.
Tube axis
OA is known as the "rollup" vector
or chiral vector
• All armchair chiralities of CNT display metallic properties (green
circles) n - m = 3i
• All other arrangements of (n, m) in CNT display semi-conductor
properties (Blue circles)
Conditivity dependence on chiral vectors
20 nm
Interlayer spacing
Lattice packing parameter
Lattice parameter (nm) Interlayer spacing (nm)
Armchair (10,10) 1.678 0.338
Zigzag (17,0) 1.652 0.341
Chiral (12,6) 1.652 0.339
Packing Behavior of Bundle of SWNT Ropes
• The structure of the nanotube influences its properties,
including conductance, density, and lattice structure.
• The wider the diameter of the nanotube the more it behaves
like graphite.
• The narrower the diameter the more its intrinsic properties
depend on type.
Structure dependence of CNT Properties
Formation of CNTs
Fabrication of CNTs
Arc discharge (Plasma arcing)
• Potential of 20-25 V is applied across carbon electrodes.
• Electrodes of 5-20 m diameter separated by 1 mm at 500 torr of flowing helium.
• Carbon ejected from positive electrode and form nanotubes on negative electrode.
• If electrode contains cobalt, nickel, or iron, single-walled CNTs are produced.
• If no catalyst contained in the carbon electrode, multi-walled CNTs form.
• Single-walled CNTs are 1-5 nm with a length of 1 m.
Laser evaporation
• Graphite target with argon in quartz tube been heated to 1200oC
• Graphite contains cobalt or nickel
• 10-20 nm in diameter and 100 m long.
Chemical vapor deposition
• Decomposing a hydrocarbon (CH4) at 550-1100oC.
• Substrate need to contain cobalt, nickel, or iron.
• Produced CNTs with open ends.
The schematic diagram of synthesizing
MWNT(a) and SWNT(b) by arc discharge.
CNT Synthesis by Arc Discharge (MWNT vs SWNT)
cathode Anode
The fullerenes appear in the soot that is formed, while
the nanotubes are deposited on the opposing electrode,
the cathode.
More hydrogen in the coal tend to form more feather-
like amorphous carbon.
Carbon molecule formation
More hydrogen in the coal tend to form polycyclic
hydrocarbons.
Carbon molecule formation in soot
Cathode deposits consist of two phases, feathers and
matrix.
Matrix is composed of nanotubes and nanoparticles
(shortened scale-like nanotubes).
Feathers consists of the same mix but with amorphous
carbon, called pyrolytic carbon.
More hydrogen tend to form more feather-like
amorphous carbon.
Cathode deposit
Arcing using Coal vs Graphite
In the soot
Other than C60 and C70 - fullerenes, polycyclic hydrocarbons are formed due
to hydrogen in the coal.
On the cathode
The ratio of feathers to matrix increases with hydrogen content in the coal.
Microfilament formation rather than nanotubes from coal.
http://www.acdlabs.com/iupac/nomenclature/79/r79_73.htm
Fused Polycyclic Hydrocarbons
naphthalene
Hard outer shell consisting of fused material
Softer fibrous core containing discrete nanotubes
and nanoparticles
T.W. Ebbesen, “Carbon Nanotubes”, Ann. Rev. Mater. Sci., 24, 235 (1994)
Cathode Deposit
Shell
Core
48. Internationales Wissenschaftliches Kolloquium
Technische Universität Ilmenau
22.-25. September 2003
Transmission Electron Micrographs of particles
formed in the presence of 4.11% cobalt.
Nanotubes (labelled point A and snakes
labelled point B), vesicles (point C) or bladders
(point D) are also observed. Single walled
structures in nanotubes can be observed by
higher resolution as described by others
Journet C, Maser WK, Bernier P, Loisea A, Lamy de la, Chapelle M, Lefrant S,
Deniard P, Lee R, Fischer JE. Nature, 1997;388:756.
Order in carbons produced by plasma arcing in the
presence of cobalt
Isotopic Analysis using Graphite Anode
Large isotopic difference
Isotopically heavy (higher 13C/12C)
Isotopically light
Carbon atoms C1
Carbon atoms C1
Isotopic Analysis using Coal Anode
Small isotopic difference
Isotopically heavy (higher 13C/12C)
Isotopically light
Carbon atoms C1
naphthalene
Much of the soot is directly derived from molecular entities in the
anode and not solely from C1 units.
For naphthalene to be incorporated in the cathode deposit, it must
survive the high temperature of the arc. It is most likely that fullerene
synthesis occurs at lower temperatures at the edge of the arc.
The wider tubes appear to be more predominant at the outer diameter
regions of the anode deposit, possibly because naphthalene survives
more readily here and can be incorporated into the structure.
SWCNT by Laser Vaporization
http://aurora.wells.edu/~ccs/theses/chapin.ppt
Single-walled carbon
nanotubes
1000°C with CH4
Multi-walled carbon
nanotubes
700°C with C2H2
CNT Synthesis by CVD
For acetylene over iron particles at 700oC (ref)
For structure are formed
1. Amorphous carbon layers on the surface of the catalyst
2. Filaments of amorphous carbon
3. Graphitic layers covering metal particles
4. MWNT (covered with amorphous carbon on their outer layer
As grown CNTs generally do not look fully formed. However, the structure is
much improved after heat treatment to 2500-3000oC in argon.
CNT Synthesis by CVD using Acetylene
over Iron Particles
CNT Synthesis by CVD using Acetylene over Co
and Fe Catalysts on Silicon or Zeolite Substrates
For acetylene over Co and Fe catalysts supported on silica or zeolite
• Carbon deposition activity seems to relate to the coboltcontent of the
catalyst
• Nanotube’s selectivity seems to be a function of the pH in catalyst
preparation
• Fullerenes and SWNT are also found among the MWNTs
CNT Synthesis by CVD using Ethylene
For CNTs synthesized by CVD using ethylene and catalysts
1. Metals (Fe, Co, Ni ) seems to induce the growth of isolated SWNTs or
SWNT bundles.
2. SWNTs and DWNTs are formed on Mo-Fe alloy.
3. Reaction temperatures of 545oC for Ni-catalyzed CVD, and 900oC for
uncatalyzed process within pores of aluminum membrane.
4. Resultant CNTs have no caps.
CNT Synthesis by CVD using Methane
For CNTs synthesized by CVD using methane
1. High yield of SWNTs obtained by catalytic decomposition of H2/CH4
mixture over well-dispersed metal particles on MgO at 1000oC
2. Synthesis of composite powders containing well-dispersed CNTs can be
achieved by selective reduction in H2/CH4 of oxide solid solutions between a
non-reducible oxide such as Al2O3 or MgAl2O4 and one or more transition
metal oxides.
3. The decomposition of CH4 over the freshly formed nanoparticles prevents
their further growth and thus results in a very high proportion of SWNTs and
less MWNTs.
Iron-containing compounds as substrates make good nanotube arrays
1998 Nature 395”878-81
1999 J. Chem. Phys. B. 103: 4223-27
Two general growth modes of nanotube in chemical vapor deposition. Left
diagram: base growth mode. Right
diagram: tip growth mode.
Growth Mechanism of CNTs
Other CNTs Synthesis Methods
1. Ball Milling 150 Hrs + Annealing at 1400oC for 6 Hrs (MWNTs)
2. Diffusion flame synthesis
3. Electrolysis
4. Sloar energy
5. Heat treatment of polymer
6. Low temperature solid pyrolysis
合成鑽石技術的演進
•1955 美國奇異公司Bundy et al.,成功的以高溫高壓法合成鑽石
•1962 Eversole 首次以氣相方法沉積鑽石於鑽石晶種上
•1968 Derjaguin et al.,以甲烷及氫氣混合氣體在低壓下成功地合成鑽石
•1971 Angus 證實以熱鎢絲將解離的氫原子與甲烷分解的碳作用後可以
形成鑽石
•1977 Derjaguin et al.,指出數種方式可加速反應氣體中分子的裂解及鑽
石的成長
•1982 Matsumoto et al.,鑽石氣相沉積法的技術進步。利用熱燈絲、高週
波、微波、直流電弧、火炬法等
0
50
100
150
200
250
300
350
400
0 1000 2000 3000 4000 5000
Temperature ( C)
Pre
ssure
(kB
ar)
Liquid Graphite
Stable Diamond
Stable Graphite
Shock
wave
Direct HTHP
Catalyst HTHP
HFCVD,LPSSS
碳的平衡相圖
Synthesis of diamond today:
diamond CVD
• Carbon: methane (ethane, acetylene...)
• Hydrogen: H2
• Add energy, producing CH3, H, etc.
• Growth of a diamond film.
The right chemistry, but little control over the site of
reactions or exactly what is synthesized.
Microwave Plasma CVD Reactor
If diamond sheets could be made cheaply all objects that need to
be hard and indestructible would be made from diamond.
Hot Filament CVD (HFCVD)
• Flexible
• Limited Power Density
• Growth Rate = 0.2~3 m/h
• Insensitive to minor air leak
• Low cost
• An excellent “first reactor”.
Hot-Filament CVD for Diamond Film Growth
Carbon Nanostructures (II)
Graphene
Ming-Show Wong
May 2012
http://en.wikipedia.org/wiki/Graphene
64
Graphene
Graphene is a flat monolayer of carbon atoms tightly packed into a two-
dimensional (2D) honeycomb lattice, and is a basic building block for graphitic
materials of all other dimensionalities. It can be wrapped up into 0D fullerenes,
rolled into 1D nanotubes or stacked into 3D graphite.
66
•In 2004, the Manchester group obtained graphene by mechanical exfoliation of
graphite.
•They used cohesive tape to repeatedly split graphite crystals into increasingly
thinner pieces.
•The tape with attached optically transparent flakes was dissolved in acetone, and,
after a few further steps, the flakes including monolayers were sedimented on a
silicon wafer.
•Individual atomic planes were then hunted in an optical microscope.
•A year later, the researchers simplified the technique and started using dry
deposition, avoiding the stage when graphene floated in a liquid.
•Relatively large crystallites (first, only a few micrometres in size but, eventually,
larger than 1 mm and visible by a naked eye) were obtained by the technique
Scotch tape or drawing method
http://nobelprize.org/nobel_prizes/physics/laureates/2010/
Andre Geim Konstantin Novoselov
The Nobel Prize in Physics 2010
nature photonics | VOL 4 | NOVEMBER 2010
Graphene:2004 2010 C60:1985 1996 核磁共振:1970s 2003 石英光纖:1960s 2009 CCD影像:同上
石墨烯的命名來自英文的graphite(石墨) + -ene(烯類結尾),也可稱為「單層石墨」
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可應用於:透明觸控螢幕、光板、軟性電子紙甚至是太陽能電池
Novoselov, K. S., Gaim, A. et al. (2004). "Electric Field Effect in Atomically Thin Carbon Films". Science 306 (5696): 666.
Exfoliated Graphene
Monolayers and Bilayers
Monolayer Bilayer
Reflecting microscope images.
K. S. Novoselov et al., Science 306, 666 (2004).
20 m
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Home / April 23rd, 2011; Vol.179 #9 / Silicene: It could be the new graphene / File
ONE-ATOM LAYER
Silicon atoms (bright spots) in a honeycomb pattern are a new type of material known as silicene.
Credit: Bernard Aufray / CNRS, Hamid Oughaddou / University of Cergy
•幾乎透明,只吸收2.3%的光
•導熱係數高達5300W/m•K,高於奈米碳管與金剛石
•電子遷移率>15000cm2/V•s,又比奈米碳管或矽晶體高
•電阻率約10-6Ω•cm,比銅或銀更低,目前為世界上電阻最小的材料
•具有高楊氏系數(~1100GPa)、高斷裂強度(125GPa)
Keynote speech by Kostya Novoselov, Nov.2010, Academia Sinica
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線性光譜 高電子遷移率
獨特光學性質
一個原子厚
堅韌 高延展性
Introduction
3D: Graphite 2D : Graphene
Graphene is a one-atom-thick planar sheet of sp2-bonded carbon atoms that
are densely packed in a hexagonal crystal lattice.
Graphene is a giant aromatic macromolecule that conducts both electricity
and heat well in two dimensions.
:
0D: Buckyball
1D: Carbon nanotube
Graphene
Graphite
Carbon nanotube Buckyball
Mother of all graphitic forms. Graphene is a 2D building material for carbon materials of all other dimensionalities. It can be wrapped up into 0D buckyballs, rolled into
1D nanotubes or stacked into 3D graphite.
Geim, A. K. and Novoselov, K. S. (2007). "The rise of graphene". Nature Materials 6 (3): 183–191.
Characteristic Young’s modulus(Gpa) Intrinsic strength (GP)
Graphene 1100 125
CNT 1000 150
Carbon fiber 350 2.5
Steel 208 0.4
Fig. Schematic depictions of graphene crystal
structure (lattices), conduction band (blue cones
and curves), valence band (yellow cones and
curves), and Fermi level (dotted lines).
Graphene has a zero bandgap and thus behaves like a metal.
Fig. When a graphene layer is grown on a silicon
carbide substrate), broken symmetry opens a gap (D)
between the valence and conduction bands around the
so-called Dirac energy (ED), as shown in the ARPES
intensity map (lower right), but below the Fermi energy.
Characteristic
• Electron mobility in graphene is extraordinarily high
(200,000 cm2/V.s at room temperature) and ballistic
electron transport at room temperature.
Application
FET
利用Graphene所製造的電晶體其組成之
微細電路,可以微電路尺寸大幅度縮小。
Flash
其密度可達到快閃記憶體的兩倍。
Line
具備低電阻,還可提供高電子遷移率以及更佳的熱傳導性、更高的機械強度,
並減少相鄰導線間的電容耦合(capacitive coupling)效應。
Transparent conductive layer
Graphene的光通透性極高,每層吸收率僅2%,遠低於
一般氧化銦錫的15~18%。薄膜電阻值在以化學方法摻雜
(doping)過後可降至50歐姆。
Flexible graphene paper
Field effect transistor based on graphene armchair ribbon constriction
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2 Occurrence and production
2.1 Drawing method
2.2 Epitaxial growth on silicon carbide
2.3 Epitaxial growth on metal substrates
2.4 Graphite oxide reduction
2.5 Growth from metal-carbon melts
2.6 Pyrolysis of sodium ethoxide
2.7 From nanotubes
2.8 From sugar
How to make graphene
Mechanical exfoliation from highly oriented
pyrolytic graphite (HOPG):
Slicing this strongly layered material with gently rubbing it against another surface.
藉由反覆撕黏,將graphite層層
剝離成grphene sheets,最後移
植到製備元件。
Transparent tape Method
Chemical exfoliation from bulk: • Oxidized graphite (by using strong acids) was cleaved
via rapid thermal expansion or ultrasonic dispersion, and
subsequently the graphene oxide sheets were reduced to
graphene in the deoxygenation via chemical reduction.
How to make graphene
Thermal decomposition of carbon terminated
4H–SiC : 1. The hydrogen is used to clean and etch the SiC to
obtain a pristine surface.
2. The hydrogen is purged from the chamber and a
turbomolecular pump is used to reach a pressure
of 1 × 10−6 Torr.
3. The chamber is warmed up to1100°C and The
pressure in the chamber during growth is a 4 × 10−5 Torr
1. This is an approach to making GNRs by unzipping multiwalled
carbon nanotubes by plasma etching of nanotubes partly
embedded in a polymer film.
2. The GNRs have smooth edges and a narrow width distribution
(10–20 nm).
How to make graphene
Carbon nanotubes can be unzipped
to form graphene nanoribbons
a), A pristine MWCNT
was used as the
starting raw material.
b),The MWCNT was deposited on a Si
substrate and then coated with a PMMA
film. c), The PMMA–MWCNT film was
peeled from the Si substrate, turned
over and then exposed to an Ar plasma
d–g), Several possible products were generated after etching for different times: GNRs with CNT
cores were obtained after etching for a short time t1 (d); tri-, bi- and single-layer GNRs were
produced after etching for times t2, t3and t4, respectively (t4.t3.t2.t1; e–g). h, The PMMA was removed
to release the GNR.
h), The PMMA was removed to release
the GNR
Using Acetone vapour
Fig 1. Schematic of the MPCVD system
for the growth of GSs
Equipment::Commercial 1.5W ASTex MPCVD
system
Gas:10% methane and 90% hydrogen
Total pressure:30 Torr
Flow rate:200 sccm
Microwave power:1200W
Time:5 hours
The substrate holder was heated to 800 C, while the
temperature of the SS cylinder wall was about 500 C.
How to make graphene
Fig 2. (a)SEM image of GSs dispersed on a Cu grid
Fig 2. (b) TEM
image of GS on a Cu
grid
Fig 2.(c)
corresponding
SAED pattern
of the GS.
The typical sixfold asymmetry
expected for graphite/graphene
indicating the GSs have better
crystallinity.
The preferential etching of carbon-containing species adsorbed in the stacking direction relative to those adsorbed in the plane direction.
Vol 457|5 February 2009| doi:10.1038/nature07719
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DOI: 10.1021/jz1011466 |J. Phys. Chem. Lett. 2010, 1, 3101–3107
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C A R B ON 4 8 ( 2 0 1 0 ) 3 5 9 –3 6 4
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2 5 N O V E M B E R 2 0 1 0 | VO L 4 6 8 | N AT U R E
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深: SiO2/Si substrate 淺:Graphene
A pronounced smooth
surface of the GS
1580 cm-1
1329 cm-1
2653 cm-1
2653 cm-1
(2D): The GS consists of a single-layer of graphene.
1329 cm-1
(D):The defects or structural disorder exit in GSs.
The intensity ratio of the D-to-G peaks is increased with the degree of
disorder in the sheets.
Tw isting
Corrugation
Folded region
Non-uniformity
Vacancies
Distortions
Nano Res (2008) 1: 273 291
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Materials Science
and Engineering is
Hi-Tek
Let’s start a new ball
game