graphene syntheis and characterization for raman spetroscopy at high pressure
DESCRIPTION
Master Thesis Presentation, made 2009-09-04 in Luleå.TRANSCRIPT
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Single- and Double-Layer Graphene
for in-situ High-Pressure Raman scattering
Synthesis and Characterization of Carbon-based Nanomaterials
Nicolas MORAL
Supervisor: Pr. Alexander SOLDATOV
High-Pressure Spectroscopy LaboratoryDivision of Physics, Luleå Tekniska Universitet, 971 87 Luleå, SWEDEN
Department of Applied Physics and Mechanical Engineering
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Table of contents
Introduction• Carbon-based Nanomaterials• Resonance Raman Scattering• High-Pressure experiments
Review & Motivation
Methods and Materials• 2 routes to graphene at High-Pressure
Results & Discussions
Conclusion
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Introduction
Carbon-based Nanomaterials
Raman scattering
High-Pressure
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Carbon-based Nanomaterials
Carbon NanoTubes (CNTs)• ~1D objects (1*1000 nm)
- High property-to-weight ratios
• Applications- Composites, Nanoelectronics, Heat transfer- Fuel cells and drug delivery
Fullerenes• ~0D objects (ø 0.7nm)
• Applications- Nanoelectronics, Transistors- Catalyst for diamond production
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Graphene
Graphite, Graphene• Single-Layer graphene
- 2D object
- One-atom-thick
- Sp² bonds
- Honeycomb lattice
• Origin of other Carbon allotropes- Cylinder = CNT
- Sphere = Fullerenes
- Stacks = Graphite
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Graphene
Graphene• Properties
- Young’s modulus 0.5 TPa- “high” optical opacity (2.3%)
- High thermal conductivity (103 W.m-1.K-1)- Ballistic thermal/electronic behavior- Quantum Hall effect
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Graphene
Graphene• Applications
- Nanoribbons and spintronics- Ultracapacitors
- Single-molecule detection
- Bio-devices
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Introduction
Carbon-based Nanomaterials
Raman scattering
High-Pressure
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Raman scattering
Principle• Laser excitation ν0
• Phonons scattering Rayleigh ν0 +Raman ν0± νm
• Resonance Raman
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Raman Scattering
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
High-Pressure
Principle• Diamond Anvil Cell
- Simple equipment
- High pressures (up to 50GPa)
Objective• SLG: probe the hardest bond
in the world, sp² in 2D
• DLG: experiment the isolated interplane interaction
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Motivation of the thesis
Preparation of in-situ HP
Resonance Raman Spectroscopy
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Motivation of the thesis
Synthesis of Graphene• SLG, DLG, FLG; reliable and reproducible
Characterization of Graphene• Optical Microscope• Atomic Force Microscope• Electronic Microscope• Raman• …
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Methods and materials
Source Materials, Equipment, Protocols
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Methods and Materials
References samples (courtesy of Dr K. Novoselov, Manchester)
• Graphene on SiO2 (tape method)
Source Material• Supported Graphene
- Si/SiO2 substrates
- Mechanical exfoliation = “Tape Method”
• Free-Standing Graphene- Cu grid
- Epitaxially grown
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Methods and Materials
Equipment: Optical Microscope• Olympus BX51• 10X, 20X, 100X magnifications
Equipment: Atomic Force Microscope• AFM/STM NT-MDT Ntegra
Equipment: Scanning Electron Microscope• Materialteknik Jeol JSM 6460LV
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Methods and Materials
Equipment: Raman stage• WiTec confocal Raman imaging system CRM200
- High signal-to-noise ratio
- 1cm-1 resolution
• Lasers- Green 532nm (2.33eV) _ SpectraPhysics Millenium IV
Powers 200mW up to 5W – 15mW on stage Power densities up to 300 kW/cm²
- Red 632.8nm (1.96eV) _ Coherent Powers up to 50mW – 8mW on stage Power densities up to 150 kW/cm²
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Methods and Materials
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Methods and Materials
First route: Supported Graphene• Deposition cycle: Substrates cleaning / exfoliation / deposition• Optical observation / substrate mapping• Spectral confirmation
• Transfer into the DAC of SPECIFIC flakes (SLG/DLG)
Second route: Free-Standing Graphene• Provided by Manchester University’s collaborator
- Macroscopic sample (ø3 mm)
• Transfer into the DAC
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Methods and Materials
Route 1: Supported Graphene
Route 2: Free-Standing Graphene
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Methods and Materials
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Methods and Materials
Optical observation• Specific optical interference thanks to Si/SiO2 substrate
Spectral confirmation• Using Raman spectra and comparison to reference samples
Transfer• Protocol involving HoleyCarbonFilms (Quantifoil ™)
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Methods and Materials
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Methods and Materials
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Methods and Materials
Loading into the DAC• “Sandwiching” the flake• Cutting the sandwich (sample chamber <200µm)
• Loading into the DAC- Pressure-transmitting medium: ethanol-methanol
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Methods and Materials
Route 1: Supported Graphene
Route 2: Free-Standing Graphene
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Methods and Materials
Source Material: Free-Standing Single-Layer Graphene• Epitaxial growth on Ni substrate• Covered by PMMA• Ni etching in acid
• PMMA-SLG fishing with Copper grid• PMMA etching in acetone
Loading into the DAC• Sandwich method
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Methods and Materials
100 µm
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Results and discussions
Route 1: Supported GrapheneDeposition Cycle
Optical Observation
Spectral Confirmation
Transfer
Route 2
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Supported Graphene
Substrates cleanliness• Crucial step for successful deposition
Deposition optimization• Tape selection• Exfoliation method
- Optimal = small crumbs
• Deposition method- Pressing/rubbing/etching
- Optimal = rubbing
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Conclusion
Step 1: COMPLETE• Fast deposition cycle (10-20 samples a day)• Reproducible results
• To be optimized ?- Increased average flakes’ size might be possible
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Results and discussions
Route 1: Supported GrapheneDeposition Cycle
Optical Observation
Spectral Confirmation
Transfer
Route 2
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Optical observation
Finding the flake(s)
Identification (contrast)• SLG• DLG• FLG• MLG• Graphite
Substrate mapping
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Optical observation
GraphiteGlue
DLG ?
FLG
MLGSLG ?
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Results and discussions
Route 1: Supported GrapheneDeposition Cycle
Optical Observation
Spectral Confirmation (reference spectra)
Transfer
Route 2
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Reference spectra
Manchester’s graphene on SiO2
• SLG• DLG• FLG
• Comparison to Graphite reference (NG)
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Reference spectra
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100
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1300
1400
SLG DLG FLG
ManchesterGraphene_1,96eV_referenceComparision SLG DLG FLG
Inte
nsi
ty (
a.u
.)
Raman shift (cm-1)
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Reference spectra
2500 2525 2550 2575 2600 2625 2650 2675 2700 2725 2750 2775 2800
0
200
400
600
800
1000
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1400 GprimeSLG GprimeBLG GprimeFLG
ManchesterGraphene_1,96eV_referenceComparision SLG BLG on flake 1
Inte
nsi
ty (
a.u
.)
Raman shift (cm-1)
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Reference spectra
2500 2550 2600 2650 2700 2750 2800
0
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2000 GprimeSLG GprimeBLG GprimeFLG NaturalGraphite
ManchesterGraphene_1,96eV_referenceComparision flakes SLG DLG FLG with NG
Inte
nsi
ty (
a.u
.)
Raman shift (cm-1)
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Conclusion
Reference samples characterization• Clear identification of the main 3 target samples is possible
- SLG
- DLG
- FLG
- Gprime is a fingerprint (shape and peak-fitting)
- G’/G ratio is also used
• Transpose to our graphene samples
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Results and discussions
Route 1: Supported GrapheneDeposition Cycle
Optical Observation
Spectral Confirmation (deposited samples)
Transfer
Route 2
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Spectral confirmation
Raman spectrum• Red laser
- SLG
2500 2550 2600 2650 2700 2750 2800
0
250
500
750
1000
1250
1500
1750
Inte
nsi
ty (
a.u
.)
Raman shift (cm-1)
M1flake2 TM1flake6
NGdepositions_1,96eVcomparison SLG flake to Manchester reference
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Spectral confirmation
Raman spectrum• Red laser
- DLG
2400 2450 2500 2550 2600 2650 2700 2750 2800
0
100
200
300
400
500
NGdepDLGred ManchesterDLG
DLG deposited from NGRed laser 1,96eVcomparison with reference sample
Inte
nsi
ty (
a.u
.)
Raman shift (cm-1)
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Spectral confirmation
Raman spectrum• Red laser
- 3LG
2500 2550 2600 2650 2700 2750 2800
-200
0
200
400
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800
1000
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2000
2200
2400 M1BLG TM1flake4
NGdepositions_1,96eVcomparison 3LG flake to Manchester reference
Inte
nsi
ty (
a.u
.)
Raman shift (cm-1)
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Spectral confirmation
Raman spectrum• Green laser
- SLG
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Spectral confirmation
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Spectral confirmation
Raman spectrum• Green laser
- DLG
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Spectral confirmation
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Spectral confirmation
1000 1250 1500 1750 2000 2250 2500 2750 3000 3250 3500
0
500
1000
1500
2000
2500
3000 NGdepSLGred NGdepSLGgreen
SLG deposited from NGGreen Laser 2,33eV Red laser 1,96eV
Inte
nsi
ty (
a.u
.)
Raman shift (cm-1)
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Spectral confirmation
SLG samples• Red laser
- single peak G’ = 2630 cm-1
- FWHM = 24 cm-1
- G’/G ratio >> 1
• Green laser- Single peak G’ = 2670 cm-1
- FWHM = 26 cm-1
- G’/G ratio >> 1
• SLG identification complete and identical to literature reviews
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Spectral confirmation
1000 1250 1500 1750 2000 2250 2500 2750 3000 3250 3500
0
500
1000
1500
2000 NGdepDLGred NGdepDLGgreen
DLG deposited from NGGreen Laser 2,33eV Red laser 1,96eV
Raman shift (cm-1)
Inte
nsi
ty (
a.u
.)
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Spectral confirmation
DLG samples• Red laser
- G’ peak = 4peaks
- FWHM ≈ 24 cm-1
- G’/G ratio ≈ 1
• Green laser- G’ peak = 4peaks
- FWHM ≈ 24 cm-1
- G’/G ratio ≈ 1
• DLG identification complete and identical to literature reviews
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Conclusion
Step 2: COMPLETE • Characterization of produced samples
- Non-destructive
- Fast spectra
- Peak-fitting software = reliable results
- SLG / DLG / FLG
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Results and discussions
Route 1: Supported GrapheneDeposition Cycle
Optical Observation
Spectral Confirmation (deposited samples)
Transfer
Route 2
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Transfer
Method 1: IPA• Lifting the “grid/film & flake” off the substrate with IPA• Unsuccessful so far:
- Grids’ stiffness
Method 2: KOH• Etching the SiO2 layer off
• Unsuccessful so far:- Flakes swim away
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Conclusion
Route 1: Supported Graphene
• Step 1: DEPOSITION COMPLETE
• Step 2: CHARACTERIZATION COMPLETE
• Step 3: Transfer incomplete
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Results and discussions
Route 1
Route 2: Free-Standing GrapheneCharacterization
Transfer
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Free-Standing Graphene
1000 1250 1500 1750 2000 2250 2500 2750 3000 3250 3500
0
250
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2000
FSGgreen100X FSGgreen20X
Free-Standing GrapheneGreen laser 2,33 eV
Inte
nsi
ty (
a.u
.)
Raman shift (cm-1)
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Free-Standing Graphene
1000 1250 1500 1750 2000 2250 2500 2750 3000 3250 3500
0
200
400
600
800
1000
FSGred100X FSGred20X
Free-Standing GrapheneRed laser 1,96 eV
Inte
nsi
ty (
a.u
.)
Raman shift (cm-1)
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Free-Standing Graphene
1000 1250 1500 1750 2000 2250 2500 2750 3000 3250 3500
0
250
500
750
1000
1250
1500
1750
2000
FSGred100X FSGgreen100X
Free-Standing GrapheneRed laser 1,96 eVGreen laser 2,33 eV
Inte
nsity
(a.
u.)
Raman shift (cm-1)
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Conclusion
FSG characterization COMPLETE• With both lasers• Similar results to supported graphene
- Dirtier (Dband, lots of graphitic dirt)
• With 20X objective = ready-to-load at High Pressure
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Results and discussions
Route 1
Route 2: Free-Standing GrapheneCharacterization
Transfer
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Transfer
Samples size reduction: IN PROGRESS• First cuts successful, without damage/alteration
• Down to 100 µm so far
• FS SLG damaged
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Transfer
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Conclusion
Route 2: Free-Standing Graphene
• Step 1: CHARACTERIZATION COMPLETE- SLG available for transfer
- DLG is missing as a free-standing sample
• Step 2: Transfer incomplete
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Summary of Conclusions
Route 1: Supported Graphene
Route 2: Free-Standing Graphene
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Summary of Conclusions
Synthesis of target samples COMPLETE• Supported SLG / DLG
- “tape” method
- Fast, reproducible, reliable
• Free-Standing SLG available
Characterization of available samplesCOMPLETE• Supported SLD / DLG / 3LG• Free-Standing SLG
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Future Work
Synthesis• Get Free-Standing DLG• Optimizing the deposition cycle
Characterization• Correlate spectra with AFM measurements
Transfer• Complete loading for both routes
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Gband 1580cm-1
(intensity a.u.)
G’band 2670cm-1
(intensity a.u.)
Future Work
Gband
G’band
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Acknowledgements
Pr Alexander SOLDATOV• Supervisor, LTU
Dr Kostya NOVOSELOV• University of Manchester (UK)
My saviors• Zoubir Ayadi, EEIGM (France)
• Lennart Wallström, LTU
My colleagues• Dr Shujie You
• Illya Dobryden, PhD
• Murat Özturk, project student
• Johnny Grahn, Johanne MouzonNils Almqvist
• David Olevik & Mattias Mases
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology
Thank you for your attention
Please address your questions NOW !
MORAL Nicolas
High-Pressure Spectroscopy LabDivision of Physics, TFMLuleå University of Technology