Efremova_2014_Toxicity of Graphene Shells, Graphene Oxide, And Graphene
Graphene Technology: Roadmap to...
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CAMBRIDGE UNIVERSITY DEPARTMENT OF ENGINEERING AND MATERIALS GROUP SPECTROSCOPY GROUP NANOMATERIALS AND Graphene Technology: Roadmap to Applications Andrea C. Ferrari Department of Engineering, Cambridge University, Cambridge, UK
Transcript of Graphene Technology: Roadmap to...
CAMBRIDGE UNIVERSITYDEPARTMENT OF ENGINEERING
ELECTRONIC DEVICES AND MATERIALS GROUPSPECTROSCOPY GROUPNANOMATERIALS AND
Graphene Technology: Roadmap to Applications
Andrea C. FerrariDepartment of Engineering, Cambridge University, Cambridge, UK
CAMBRIDGE UNIVERSITYDEPARTMENT OF ENGINEERING
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2
One Atom Thin
Strength
HighlyStretchable
Linear Spectrum
Unique OpticalProperties
High Mobility
Quantum Hall Effect
Transistors
Photovoltaics
TransparentConductors
Composites
Membranes/Gas Barrier
?
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Material Fracture Strain Material Fracture Strain
Silicon ～0.7% Poly- ZnO 0.03%
ITO 0.58～1.15% Polyimide 4%
Au 0.46% Graphene >15-20%
Bendability of Electronic Materials
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Drawing:(micro) mechanical cleavage of graphite
How to Make Graphene?
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How to Make Graphene?
GRAPHITE ISSTRONGLY LAYERED
SLICE DOWN TO ONE ATOMIC PLANE
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Graphene Production
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SKKU ProcessBae Nature Nano (2010)
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Industrial graphite Industrial graphite purification & exfoliationpurification & exfoliation
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Chemical Exfoliation of Chemical Exfoliation of GrapheneGraphene
28 April 2011
Large area graphene coverage
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+
Ideal case: 100% monolayergraphene flakes
graphite
Ultrasonication
Liquid phase exfoliation
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Dispersion in organic solvent
Y. Hernandez et al. Nat. Nano. (2008) M. Lotya et al. JACS (2009)
Solvent with high surface tension prevents re-aggregations!
Liquid phase exfoliation
Dispersion in water-surfactant solution
Surfactant compensates repulsion between water and graphene.
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0 400 800 12000
4
8
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20N= 108
Num
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f fla
kes
Area (nm2)1 2 3 4 5
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Number of layers
N= 108
Yield(monolayer)~70%
Liquid phase exfoliation in waterTEM statistics
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Issue: Monolayer, bi-layer, tri-layer have same density (ρ)!
We exploit the effect of surfactant coverage
Sorting number of layers via Density Gradient Ultracentrifugation (DGU)
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After DGU
The buoyant density increase with N
ρ
NOW: Density depends on number of layers
N-layers
.
.
A. Green, M. Hersam, Nano lett. (2009)
Sorting number of layers via DGU
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2600 2700 2800
2D
2600 2700 2800R am an sh ift (cm -1)
2600 2700 2800
2D
2D
Sorting number of layers via DGU
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200 nm
Sorting number of layers via DGU
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Ink-Jet Printing Graphene-Ink
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On Si/SiO2 On Optical Fiber
Deterministic Placement
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1400 2100 2800
0
10000
20000
Inte
nsity
[A
.U.]
Raman shift [cm-1]
Bottom
Top
Overlap
BILAYER TWIST
TOP
OVERLAP
BOTTOM
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Wafer Scale Graphene Transfer
Kim et al Nature 2010
Mechanicalpeeling offin water
Support/Graphene/Ni(or Cu)/SiO2
Ni (or Cu)
SiO2
Rapid etchingwith FeCl3 (aq)
Graphene onpolymer support
Graphene onarbitrary substrate
Transfer
Patterning
Patterned graphene on Ni Patterned graphene on arbitrary substrate
Post-patterningPre-patterning
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LC : 10 μmLW : 5 μm
16,200 FET devices
Y. Lee et al. NanoLett., 10, 490 (2010)
Wafer Scale Graphene Devices
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Graphitic Carbon For LHC
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Preparation for SPS magnet prototype graphitic coating
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Gas Diffusion Barrier
CO2
AA
O2
H2O
Migration of flavors
Gas barrier diffusion properties
Barrier to oxygen
Barrier to CO2 gas
Industrial specifications
compatible with blow molding production rate
few seconds Deposition time
Packaging regulationRecyclable
food contact safe
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Thickness distribution
0
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100
0 5 10 15 20 25 30 35
Point
Thic
knes
s (n
m)
Vd = 60 nm/s
Uniformity = ± 15%
C2H2: 160 sccmMWP: 350 WT1 : 1 sT2 : 1 sP1 : 50 mbarsP2 : 0.1 mbars
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0,0
5,0
10,0
15,0
20,0
25,0
0,0 10,0 20,0 30,0 40,0 50,0 60,0Time (weeks)
%C
O2
Loss
PET a-C:H 60 nm a-C:H : 150 nm
CSD
Beer- CSD (17.5% of CO2 loss) - 44 weeks with 60 nm a-C:H
- 52 weeks with 150 nm a-C:H
- Beer (10% of CO2 loss) -25 weeks with 60 nm a-C:H
-30 weeks with 150 nm a-C:H
- Non coated PET bottle- 4 to 10 weeks shelf life
0
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30
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She
lf lif
e (w
eeks
)
CAMBRIDGE UNIVERSITYDEPARTMENT OF ENGINEERING
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Bunch,McEuen, Nano Lett 2008
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Com
posi
tes
Stra
in S
enso
r
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Optical properties
Graphene can be visualized optically
The optical image contrast scales with the number of layers
Confocal Rayleigh mapOptical micrograph
Casiraghi, C. et al Nano Lett. 7, 2711 (2007).
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Optical properties
SLG reflects << 0.1% of the incident light in the visible region, raising to ~2% for 10 layers
A=1-T=πα=2.3%
T = (1 + 0.5πα)−2 ≈ 1 − πα ≈ 97.7%
Universal optical conductanceG0 = e2 /4ħ ≈ 6.08 × 10−5Ω−1
Nair Science 2008Kuzmenko PRL 2008
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ITO drawbacks
• Increasing cost due to Indium scarcity
• Processing requirements, difficulties in patterning
• Sensitivity to acidic and basic environments
• Brittleness
• Wear resistance
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ITO replacements
200 400 600 800
20
40
60
80
100
ITO ZnO/Ag/ZnO TiO2/Ag/TiO2 Arc discharge SWNTs
Tran
smitt
ance
(%)
Wavelength (nm)
Metal grids, metallic nanowires, metal oxides and SWNTs have been explored as ITO alternative
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200 400 600 800
20
40
60
80
100
Graphene ITO ZnO/Ag/ZnO TiO2/Ag/TiO2 Arc discharge SWNTs
Tran
smitt
ance
(%)
Wavelength (nm)
Graphene films have higher T over a wider wavelength range with respect to SWNT films, thin metallic films, and ITO
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For n→0, σdc,min ≈ 4e2/h
⇒ Rs ≈ 6kΩ/ for an ideal intrinsic SLG with T ≈ 97.7%
Thus, ideal intrinsic SLG, would beat the best ITO only in terms of T, not Rs
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100 102 104 106 108 1010 101240
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n=3.4x1012 cm-2
μ=2x104 cm2/ Vs
Rs(Ω/sq)
Tran
smitt
ance
(%)
LPE RGO PAHs CVD MC Graphene calc.
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Graphene-based flexible smart window
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Rod coating
PET film
Rod coaterGraphenedispersion
Wire winding
SubstrateGraphenedispersion
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On PET~ 500Ω sheet resistance ~ 80% transparency
Transparent conductor
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VVPolymer dispersedLiquid Crystal
Flexible, transparentPolymer support
Graphene basedtransparent electrode
Polymer dispersed Liquid Crystal: Schematic
Flexible, transparentPolymer support
Polymer dispersedLiquid Crystal
Graphene basedtransparent electrode
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Touch screens
Considering the Rs and T required, GTCFs produced via LPE offer a viable way towards low cost devices
The TC requirements for touch screens are Rs ≈ 500 − 2000Ω/ and T>90%
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Transparentgraphene film
Patterned Graphene film on PET
4 inch scale graphene film on Flexible Substrate
4 inch scale graphene film on Stretchable Substrate
Wafer-Scale Synthesis and Transfer
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SKKU Touch screen
Bae, S. et al. Nature Nano (2010)
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Flexible, Foldable AMOLED Display
• Front Plane : Touch Screen, OLED • Back plane : TFTs
Substrate
Anode(ITO)
Touch Screen
CathodeOLED
TFT
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Photovoltaic devices
Graphene can fulfil multiple functions in PV devices:
1) Transparent conductor window
2) Photoactive material
3) Channel for charge transport
4) Catalyst
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Silicon solar cells
η up to ~25%
Graphene TC Films can be used as window electrodes in inorganic solar cells
Silicon solar cells dominate the current PV technology
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Organic solar cells
η > 12% could be possible Yong, V. ,Tour, J. M. Small 6, 313 (2009)
• Transparent conductor window
• Photoactive material
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Dye Sensitized Solar Cell
II33-- II33
--II-- II--
O'Regan and Gratzel, Nature, 252, 737 (1991)
Transparent conductive electrode
Graphene bridge structure
Counter electrode
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Graphene electrode is prepared by drop casting the dispersion on quartz substrate
DSSCs assembly
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Photodetectors
GPDs can work over a much broader wavelength range
GPDs have a faster response compared to traditional PDs
Graphene based PDs (GPDs)
Avouris, et al.
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Graphene for photodetection•high mobility and Fermi velocity potentially allow high operating speeds→ ft 40 GHz / 10 Gbit/s demonstrated• absorption of 2.3 % per layer constant over the visible range to the infrared• zero band-gap semiconductor→ no cut-off wavelength• dark current
Mueller et. al., Nature Photonics 4, 297 (2010).
Nair et. al., Science 6, 5881 (2008).
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Working principle
Metal-induced doping
Giovanetti et. al., Phys. Rev. Lett. 101, 026803 (2008).
e-h pair creationMetal
e-h separation
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Light emitting devices
• TC films based on graphene and graphene oxide have been demonstrated for OLED and light-emitting electrochemical cell
• Electroluminescence observed in graphene could lead to novel emitting devices based entirely on graphene
Essig, S. et al. Nano Lett. 10, 1589 (2010)
Organic light emitting diodes (OLED)
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Making GraphenePhotoluminescent
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3s, scale 5μm
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PL
Elastic Scattering
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e-e relaxation(~100fs)
Cooling by phonon emission (~1ps)
Optical pumping
Broadband Nonlinear PL
PL
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Elastic light scattering image
50 x 50 µm2Heinz+Wang+Sthor+Hartschuh
Broadband Nonlinear PL
Nonlinear PL image
Red and Blue PL, as result of e-e collisions
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MirrorMirror
Laser gainmedia
CWUltrafast Pulses< 10-12 second
A saturable absorber turns a continuous wave (CW) laser into an ultrafast laser
Ultrafast lasers
Mode-locked laser produces:
Ultra-short Pulse Duration
Enhanced Peak Power
Wide Spectrum
SaturableAbsorber
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Normal Cancerous
Essential tools for cutting-edge research in Physics, Engineering, Chemistry, Biology, Nanotechnology
Applications of mode-locked lasers
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The effect of a saturable absorber
First, imagine raster-scanning the pulse vs. time like this:
After many round trips, even a slightly saturable absorber can yield a very short pulse.
Short time (fs)
Inte
nsity
Round trips (k)
k = 1
k = 7
Notice that the weak pulses are suppressed, and the strong pulse shortens and is amplified.
k = 2k = 3
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requires molecular beam epitaxy growth of GaInAs/GaAsheterostructures
ion implantation (Ni, Be, etc) to reduce relaxation time
can work only in reflective mode
Current technology of Semiconductor Saturable Absorber Mirrors (SESAM)
Problems with current technology
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e-e relaxation(~100fs)
Cooling by phonon emission (~1ps)
Optical pumping
Graphene as an ultrafast ultrawide band saturable absorber
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1515 1530 1545 1560 15750.0
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.u.)
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70
Graphene
CNTs
Z. Sun et al. Nano Research (2010)
Exploiting the wide graphene absorption band: Wavelength tunability
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1525nm 1534nm 1541nm 1547nm 1553nm
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Highly-doped Er3+ fiberWDM
Pump laser
PC
Graphene mode-locker
Coupler
ISO
Output
Graphene-SMMA polymer composite
Ultrafast laser
Z. Sun et al. ACS nano 4, 803, 2010
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Graphene Mode-locked Laser
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Wavelength-tuneable Graphene Mode-locked Laser
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74
One Atom Thin
Strength
HighlyStretchable
Linear Spectrum
Unique OpticalProperties
High Mobility
Quantum Hall Effect
Transistors
Photovoltaics
TransparentConductors
Composites
Membranes/Gas Barrier
?
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Potential of Graphene
Science Engineering Technology
FlexibleDisplay
Touch Panel
High speedTransistor
RFIC, Sensor
Solar cellBattery
Supercap.
Conductive inkEMI screen ink
Dispaly/Solar cellPackag
LEDlighting, BLUAutomobile ECUPC
Automobile Air plane components
Graphene
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A. LombardoB. Bonetti
T.J. EchtermeyerZ. Sun
D. PopaS. Piscanec
F. BonaccorsoG. Calogero
T. HasanG. PriviteraF. Torrisi
T. M. G. MohiuddinR. R. NairC. Galiotis
D.M. Basko
E. Lidorikis
A.HartschuhH. Qian
T. Gokus
T. RyhanenS. LacourJ. KiviojaA. Colli
P. BeecherZ. Radivojevic
Thanks to
Jong-Hyun AhnByung Hee Hong
K. S. NovoselovA. K. Geim
P. ChiggiatoM. Taborelli
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Acknowledgements
