Single- and Double-Layer Graphene  for in-situ High-Pressure Raman scattering Synthesis and Characterization  of Carbon-ba...
Table of contents <ul><li>Introduction </li></ul><ul><ul><li>Carbon-based Nanomaterials </li></ul></ul><ul><ul><li>Resonan...
Introduction Carbon-based Nanomaterials Raman scattering High-Pressure
Carbon-based Nanomaterials <ul><li>Carbon NanoTubes (CNTs) </li></ul><ul><ul><li>~1D objects (1*1000 nm) </li></ul></ul><u...
Graphene <ul><li>Graphite, Graphene </li></ul><ul><ul><li>Single-Layer graphene </li></ul></ul><ul><ul><ul><li>2D object <...
Graphene <ul><li>Graphene </li></ul><ul><ul><li>Properties </li></ul></ul><ul><ul><ul><li>Young’s modulus 0.5 TPa </li></u...
Graphene <ul><li>Graphene </li></ul><ul><ul><li>Applications </li></ul></ul><ul><ul><ul><li>Nanoribbons and spintronics </...
Introduction Carbon-based Nanomaterials Raman scattering High-Pressure
Raman scattering <ul><li>Principle </li></ul><ul><ul><li>Laser excitation  ν 0 </li></ul></ul><ul><ul><li>Phonons scatteri...
Raman Scattering
High-Pressure <ul><li>Principle </li></ul><ul><ul><li>Diamond Anvil Cell </li></ul></ul><ul><ul><ul><li>Simple equipment <...
Motivation of the thesis Preparation of in-situ HP  Resonance Raman Spectroscopy
Motivation of the thesis <ul><li>Synthesis of Graphene </li></ul><ul><ul><li>SLG, DLG, FLG; reliable and reproducible </li...
Methods and materials Source Materials, Equipment, Protocols
Methods and Materials <ul><li>References samples  (courtesy of Dr K. Novoselov, Manchester) </li></ul><ul><ul><li>Graphene...
Methods and Materials <ul><li>Equipment: Optical Microscope </li></ul><ul><ul><li>Olympus BX51 </li></ul></ul><ul><ul><li>...
Methods and Materials <ul><li>Equipment: Raman stage </li></ul><ul><ul><li>WiTec confocal Raman imaging system CRM200 </li...
Methods and Materials
Methods and Materials <ul><li>First route: Supported Graphene </li></ul><ul><ul><li>Deposition cycle: Substrates cleaning ...
Methods and Materials Route 1: Supported Graphene Route 2: Free-Standing Graphene
Methods and Materials
Methods and Materials <ul><li>Optical observation </li></ul><ul><ul><li>Specific optical interference thanks to Si/SiO2 su...
Methods and Materials
Methods and Materials
Methods and Materials <ul><li>Loading into the DAC </li></ul><ul><ul><li>“ Sandwiching” the flake </li></ul></ul><ul><ul><...
Methods and Materials Route 1: Supported Graphene Route 2: Free-Standing Graphene
Methods and Materials <ul><li>Source Material: Free-Standing Single-Layer Graphene </li></ul><ul><ul><li>Epitaxial growth ...
Methods and Materials 100 µm
Results and discussions <ul><ul><li>Route 1: Supported Graphene </li></ul></ul><ul><ul><li>Deposition Cycle </li></ul></ul...
Supported Graphene <ul><li>Substrates cleanliness </li></ul><ul><ul><li>Crucial step for successful deposition </li></ul><...
Conclusion <ul><li>Step 1:  COMPLETE </li></ul><ul><ul><li>Fast deposition cycle (10-20 samples a day) </li></ul></ul><ul>...
Results and discussions <ul><ul><li>Route 1: Supported Graphene </li></ul></ul><ul><ul><li>Deposition Cycle </li></ul></ul...
Optical observation <ul><li>Finding the flake(s) </li></ul><ul><li>Identification (contrast) </li></ul><ul><ul><li>SLG </l...
Optical observation Graphite Glue DLG ? FLG MLG SLG ?
Results and discussions <ul><ul><li>Route 1: Supported Graphene </li></ul></ul><ul><ul><li>Deposition Cycle </li></ul></ul...
Reference spectra <ul><li>Manchester’s graphene on SiO 2 </li></ul><ul><ul><li>SLG </li></ul></ul><ul><ul><li>DLG </li></u...
Reference spectra
Reference spectra
Reference spectra
Conclusion <ul><li>Reference samples characterization </li></ul><ul><ul><li>Clear identification of the main 3 target samp...
Results and discussions <ul><ul><li>Route 1: Supported Graphene </li></ul></ul><ul><ul><li>Deposition Cycle </li></ul></ul...
Spectral confirmation <ul><li>Raman spectrum </li></ul><ul><ul><li>Red laser </li></ul></ul><ul><ul><ul><li>SLG </li></ul>...
Spectral confirmation <ul><li>Raman spectrum </li></ul><ul><ul><li>Red laser </li></ul></ul><ul><ul><ul><li>DLG </li></ul>...
Spectral confirmation <ul><li>Raman spectrum </li></ul><ul><ul><li>Red laser </li></ul></ul><ul><ul><ul><li>3LG </li></ul>...
Spectral confirmation <ul><li>Raman spectrum </li></ul><ul><ul><li>Green laser </li></ul></ul><ul><ul><ul><li>SLG </li></u...
Spectral confirmation
Spectral confirmation <ul><li>Raman spectrum </li></ul><ul><ul><li>Green laser </li></ul></ul><ul><ul><ul><li>DLG </li></u...
Spectral confirmation
Spectral confirmation
Spectral confirmation <ul><li>SLG samples </li></ul><ul><ul><li>Red laser </li></ul></ul><ul><ul><ul><li>single peak G’ = ...
Spectral confirmation
Spectral confirmation <ul><li>DLG samples </li></ul><ul><ul><li>Red laser </li></ul></ul><ul><ul><ul><li>G’ peak = 4peaks ...
Conclusion <ul><li>Step 2: COMPLETE  </li></ul><ul><ul><li>Characterization of produced samples </li></ul></ul><ul><ul><ul...
Results and discussions <ul><ul><li>Route 1: Supported Graphene </li></ul></ul><ul><ul><li>Deposition Cycle </li></ul></ul...
Transfer <ul><li>Method 1: IPA </li></ul><ul><ul><li>Lifting the “grid/film & flake” off the substrate with IPA </li></ul>...
Conclusion <ul><li>Route 1: Supported Graphene </li></ul><ul><ul><li>Step 1: DEPOSITION COMPLETE </li></ul></ul><ul><ul><l...
Results and discussions <ul><ul><li>Route 1 </li></ul></ul><ul><ul><li>Route 2: Free-Standing Graphene </li></ul></ul><ul>...
Free-Standing Graphene
Free-Standing Graphene
Free-Standing Graphene
Conclusion <ul><li>FSG characterization COMPLETE </li></ul><ul><ul><li>With both lasers </li></ul></ul><ul><ul><li>Similar...
Results and discussions <ul><ul><li>Route 1 </li></ul></ul><ul><ul><li>Route 2: Free-Standing Graphene </li></ul></ul><ul>...
Transfer <ul><li>Samples size reduction: IN PROGRESS </li></ul><ul><ul><li>First cuts successful, without damage/alteratio...
Transfer
Conclusion <ul><li>Route 2: Free-Standing Graphene </li></ul><ul><ul><li>Step 1: CHARACTERIZATION COMPLETE </li></ul></ul>...
Summary of Conclusions Route 1: Supported Graphene Route 2: Free-Standing Graphene
Summary of Conclusions <ul><li>Synthesis of target samples  COMPLETE </li></ul><ul><ul><li>Supported SLG / DLG  </li></ul>...
Future Work <ul><li>Synthesis </li></ul><ul><ul><li>Get Free-Standing DLG </li></ul></ul><ul><ul><li>Optimizing the deposi...
Future Work Gband 1580cm -1 (intensity a.u.) G’band 2670cm -1 (intensity a.u.) Gband G’band
Acknowledgements <ul><li>Pr Alexander SOLDATOV </li></ul><ul><ul><li>Supervisor, LTU </li></ul></ul><ul><li>Dr Kostya NOVO...
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Graphene Syntheis and Characterization for Raman Spetroscopy At High Pressure

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Master Thesis Presentation, made 2009-09-04 in Luleå.

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Graphene Syntheis and Characterization for Raman Spetroscopy At High Pressure

  1. 1. 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 Laboratory Division of Physics, Luleå Tekniska Universitet, 971 87 Luleå, SWEDEN Department of Applied Physics and Mechanical Engineering
  2. 2. Table of contents <ul><li>Introduction </li></ul><ul><ul><li>Carbon-based Nanomaterials </li></ul></ul><ul><ul><li>Resonance Raman Scattering </li></ul></ul><ul><ul><li>High-Pressure experiments </li></ul></ul><ul><li>Review & Motivation </li></ul><ul><li>Methods and Materials </li></ul><ul><ul><li>2 routes to graphene at High-Pressure </li></ul></ul><ul><li>Results & Discussions </li></ul><ul><li>Conclusion </li></ul>
  3. 3. Introduction Carbon-based Nanomaterials Raman scattering High-Pressure
  4. 4. Carbon-based Nanomaterials <ul><li>Carbon NanoTubes (CNTs) </li></ul><ul><ul><li>~1D objects (1*1000 nm) </li></ul></ul><ul><ul><ul><li>High property-to-weight ratios </li></ul></ul></ul><ul><ul><li>Applications </li></ul></ul><ul><ul><ul><li>Composites, Nanoelectronics, Heat transfer </li></ul></ul></ul><ul><ul><ul><li>Fuel cells and drug delivery </li></ul></ul></ul><ul><li>Fullerenes </li></ul><ul><ul><li>~0D objects ( ø 0.7nm) </li></ul></ul><ul><ul><li>Applications </li></ul></ul><ul><ul><ul><li>Nanoelectronics, Transistors </li></ul></ul></ul><ul><ul><ul><li>Catalyst for diamond production </li></ul></ul></ul>
  5. 5. Graphene <ul><li>Graphite, Graphene </li></ul><ul><ul><li>Single-Layer graphene </li></ul></ul><ul><ul><ul><li>2D object </li></ul></ul></ul><ul><ul><ul><li>One-atom-thick </li></ul></ul></ul><ul><ul><ul><li>Sp² bonds </li></ul></ul></ul><ul><ul><ul><li>Honeycomb lattice </li></ul></ul></ul><ul><ul><li>Origin of other Carbon allotropes </li></ul></ul><ul><ul><ul><li>Cylinder = CNT </li></ul></ul></ul><ul><ul><ul><li>Sphere = Fullerenes </li></ul></ul></ul><ul><ul><ul><li>Stacks = Graphite </li></ul></ul></ul>
  6. 6. Graphene <ul><li>Graphene </li></ul><ul><ul><li>Properties </li></ul></ul><ul><ul><ul><li>Young’s modulus 0.5 TPa </li></ul></ul></ul><ul><ul><ul><li>“ high” optical opacity (2.3%) </li></ul></ul></ul><ul><ul><ul><li>High thermal conductivity (10 3 W.m -1 .K -1 ) </li></ul></ul></ul><ul><ul><ul><li>Ballistic thermal/electronic behavior </li></ul></ul></ul><ul><ul><ul><li>Quantum Hall effect </li></ul></ul></ul>
  7. 7. Graphene <ul><li>Graphene </li></ul><ul><ul><li>Applications </li></ul></ul><ul><ul><ul><li>Nanoribbons and spintronics </li></ul></ul></ul><ul><ul><ul><li>Ultracapacitors </li></ul></ul></ul><ul><ul><ul><li>Single-molecule detection </li></ul></ul></ul><ul><ul><ul><li>Bio-devices </li></ul></ul></ul>
  8. 8. Introduction Carbon-based Nanomaterials Raman scattering High-Pressure
  9. 9. Raman scattering <ul><li>Principle </li></ul><ul><ul><li>Laser excitation ν 0 </li></ul></ul><ul><ul><li>Phonons scattering Rayleigh ν 0 + Raman ν 0 ± ν m </li></ul></ul><ul><ul><li>Resonance Raman </li></ul></ul>
  10. 10. Raman Scattering
  11. 11. High-Pressure <ul><li>Principle </li></ul><ul><ul><li>Diamond Anvil Cell </li></ul></ul><ul><ul><ul><li>Simple equipment </li></ul></ul></ul><ul><ul><ul><li>High pressures (up to 50GPa) </li></ul></ul></ul><ul><li>Objective </li></ul><ul><ul><li>SLG: probe the hardest bond in the world, sp² in 2D </li></ul></ul><ul><ul><li>DLG: experiment the isolated interplane interaction </li></ul></ul>
  12. 12. Motivation of the thesis Preparation of in-situ HP Resonance Raman Spectroscopy
  13. 13. Motivation of the thesis <ul><li>Synthesis of Graphene </li></ul><ul><ul><li>SLG, DLG, FLG; reliable and reproducible </li></ul></ul><ul><li>Characterization of Graphene </li></ul><ul><ul><li>Optical Microscope </li></ul></ul><ul><ul><li>Atomic Force Microscope </li></ul></ul><ul><ul><li>Electronic Microscope </li></ul></ul><ul><ul><li>Raman </li></ul></ul><ul><ul><li>… </li></ul></ul>
  14. 14. Methods and materials Source Materials, Equipment, Protocols
  15. 15. Methods and Materials <ul><li>References samples (courtesy of Dr K. Novoselov, Manchester) </li></ul><ul><ul><li>Graphene on SiO 2 (tape method) </li></ul></ul><ul><li>Source Material </li></ul><ul><ul><li>Supported Graphene </li></ul></ul><ul><ul><ul><li>Si/SiO 2 substrates </li></ul></ul></ul><ul><ul><ul><li>Mechanical exfoliation = “Tape Method” </li></ul></ul></ul><ul><ul><li>Free-Standing Graphene </li></ul></ul><ul><ul><ul><li>Cu grid </li></ul></ul></ul><ul><ul><ul><li>Epitaxially grown </li></ul></ul></ul>
  16. 16. Methods and Materials <ul><li>Equipment: Optical Microscope </li></ul><ul><ul><li>Olympus BX51 </li></ul></ul><ul><ul><li>10X, 20X, 100X magnifications </li></ul></ul><ul><li>Equipment: Atomic Force Microscope </li></ul><ul><ul><li>AFM/STM NT-MDT Ntegra </li></ul></ul><ul><li>Equipment: Scanning Electron Microscope </li></ul><ul><ul><li>Materialteknik Jeol JSM 6460LV </li></ul></ul>
  17. 17. Methods and Materials <ul><li>Equipment: Raman stage </li></ul><ul><ul><li>WiTec confocal Raman imaging system CRM200 </li></ul></ul><ul><ul><ul><li>High signal-to-noise ratio </li></ul></ul></ul><ul><ul><ul><li>1cm -1 resolution </li></ul></ul></ul><ul><ul><li>Lasers </li></ul></ul><ul><ul><ul><li>Green 532nm (2.33eV) _ SpectraPhysics Millenium IV </li></ul></ul></ul><ul><ul><ul><ul><li>Powers 200mW up to 5W – 15mW on stage </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Power densities up to 300 kW/cm² </li></ul></ul></ul></ul><ul><ul><ul><li>Red 632.8nm (1.96eV) _ Coherent </li></ul></ul></ul><ul><ul><ul><ul><li>Powers up to 50mW – 8mW on stage </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Power densities up to 150 kW/cm² </li></ul></ul></ul></ul>
  18. 18. Methods and Materials
  19. 19. Methods and Materials <ul><li>First route: Supported Graphene </li></ul><ul><ul><li>Deposition cycle: Substrates cleaning / exfoliation / deposition </li></ul></ul><ul><ul><li>Optical observation / substrate mapping </li></ul></ul><ul><ul><li>Spectral confirmation </li></ul></ul><ul><ul><li>Transfer into the DAC of SPECIFIC flakes (SLG/DLG) </li></ul></ul><ul><li>Second route: Free-Standing Graphene </li></ul><ul><ul><li>Provided by Manchester University’s collaborator </li></ul></ul><ul><ul><ul><li>Macroscopic sample ( ø3 mm) </li></ul></ul></ul><ul><ul><li>Transfer into the DAC </li></ul></ul>
  20. 20. Methods and Materials Route 1: Supported Graphene Route 2: Free-Standing Graphene
  21. 21. Methods and Materials
  22. 22. Methods and Materials <ul><li>Optical observation </li></ul><ul><ul><li>Specific optical interference thanks to Si/SiO2 substrate </li></ul></ul><ul><li>Spectral confirmation </li></ul><ul><ul><li>Using Raman spectra and comparison to reference samples </li></ul></ul><ul><li>Transfer </li></ul><ul><ul><li>Protocol involving HoleyCarbonFilms (Quantifoil ™) </li></ul></ul>
  23. 23. Methods and Materials
  24. 24. Methods and Materials
  25. 25. Methods and Materials <ul><li>Loading into the DAC </li></ul><ul><ul><li>“ Sandwiching” the flake </li></ul></ul><ul><ul><li>Cutting the sandwich (sample chamber <200µm) </li></ul></ul><ul><ul><li>Loading into the DAC </li></ul></ul><ul><ul><ul><li>Pressure-transmitting medium: ethanol-methanol </li></ul></ul></ul>
  26. 26. Methods and Materials Route 1: Supported Graphene Route 2: Free-Standing Graphene
  27. 27. Methods and Materials <ul><li>Source Material: Free-Standing Single-Layer Graphene </li></ul><ul><ul><li>Epitaxial growth on Ni substrate </li></ul></ul><ul><ul><li>Covered by PMMA </li></ul></ul><ul><ul><li>Ni etching in acid </li></ul></ul><ul><ul><li>PMMA-SLG fishing with Copper grid </li></ul></ul><ul><ul><li>PMMA etching in acetone </li></ul></ul><ul><li>Loading into the DAC </li></ul><ul><ul><li>Sandwich method </li></ul></ul>
  28. 28. Methods and Materials 100 µm
  29. 29. Results and discussions <ul><ul><li>Route 1: Supported Graphene </li></ul></ul><ul><ul><li>Deposition Cycle </li></ul></ul><ul><ul><li>Optical Observation </li></ul></ul><ul><ul><li>Spectral Confirmation </li></ul></ul><ul><ul><li>Transfer </li></ul></ul><ul><ul><li>Route 2 </li></ul></ul>
  30. 30. Supported Graphene <ul><li>Substrates cleanliness </li></ul><ul><ul><li>Crucial step for successful deposition </li></ul></ul><ul><li>Deposition optimization </li></ul><ul><ul><li>Tape selection </li></ul></ul><ul><ul><li>Exfoliation method </li></ul></ul><ul><ul><ul><li>Optimal = small crumbs </li></ul></ul></ul><ul><ul><li>Deposition method </li></ul></ul><ul><ul><ul><li>Pressing/rubbing/etching </li></ul></ul></ul><ul><ul><ul><li>Optimal = rubbing </li></ul></ul></ul>
  31. 31. Conclusion <ul><li>Step 1: COMPLETE </li></ul><ul><ul><li>Fast deposition cycle (10-20 samples a day) </li></ul></ul><ul><ul><li>Reproducible results </li></ul></ul><ul><ul><li>To be optimized ? </li></ul></ul><ul><ul><ul><li>Increased average flakes’ size might be possible </li></ul></ul></ul>
  32. 32. Results and discussions <ul><ul><li>Route 1: Supported Graphene </li></ul></ul><ul><ul><li>Deposition Cycle </li></ul></ul><ul><ul><li>Optical Observation </li></ul></ul><ul><ul><li>Spectral Confirmation </li></ul></ul><ul><ul><li>Transfer </li></ul></ul><ul><ul><li>Route 2 </li></ul></ul>
  33. 33. Optical observation <ul><li>Finding the flake(s) </li></ul><ul><li>Identification (contrast) </li></ul><ul><ul><li>SLG </li></ul></ul><ul><ul><li>DLG </li></ul></ul><ul><ul><li>FLG </li></ul></ul><ul><ul><li>MLG </li></ul></ul><ul><ul><li>Graphite </li></ul></ul><ul><li>Substrate mapping </li></ul>
  34. 34. Optical observation Graphite Glue DLG ? FLG MLG SLG ?
  35. 35. Results and discussions <ul><ul><li>Route 1: Supported Graphene </li></ul></ul><ul><ul><li>Deposition Cycle </li></ul></ul><ul><ul><li>Optical Observation </li></ul></ul><ul><ul><li>Spectral Confirmation (reference spectra) </li></ul></ul><ul><ul><li>Transfer </li></ul></ul><ul><ul><li>Route 2 </li></ul></ul>
  36. 36. Reference spectra <ul><li>Manchester’s graphene on SiO 2 </li></ul><ul><ul><li>SLG </li></ul></ul><ul><ul><li>DLG </li></ul></ul><ul><ul><li>FLG </li></ul></ul><ul><ul><li>Comparison to Graphite reference (NG) </li></ul></ul>
  37. 37. Reference spectra
  38. 38. Reference spectra
  39. 39. Reference spectra
  40. 40. Conclusion <ul><li>Reference samples characterization </li></ul><ul><ul><li>Clear identification of the main 3 target samples is possible </li></ul></ul><ul><ul><ul><li>SLG </li></ul></ul></ul><ul><ul><ul><li>DLG </li></ul></ul></ul><ul><ul><ul><li>FLG </li></ul></ul></ul><ul><ul><ul><li>Gprime is a fingerprint (shape and peak-fitting) </li></ul></ul></ul><ul><ul><ul><li>G’/G ratio is also used </li></ul></ul></ul><ul><ul><li>Transpose to our graphene samples </li></ul></ul>
  41. 41. Results and discussions <ul><ul><li>Route 1: Supported Graphene </li></ul></ul><ul><ul><li>Deposition Cycle </li></ul></ul><ul><ul><li>Optical Observation </li></ul></ul><ul><ul><li>Spectral Confirmation (deposited samples) </li></ul></ul><ul><ul><li>Transfer </li></ul></ul><ul><ul><li>Route 2 </li></ul></ul>
  42. 42. Spectral confirmation <ul><li>Raman spectrum </li></ul><ul><ul><li>Red laser </li></ul></ul><ul><ul><ul><li>SLG </li></ul></ul></ul>
  43. 43. Spectral confirmation <ul><li>Raman spectrum </li></ul><ul><ul><li>Red laser </li></ul></ul><ul><ul><ul><li>DLG </li></ul></ul></ul>
  44. 44. Spectral confirmation <ul><li>Raman spectrum </li></ul><ul><ul><li>Red laser </li></ul></ul><ul><ul><ul><li>3LG </li></ul></ul></ul>
  45. 45. Spectral confirmation <ul><li>Raman spectrum </li></ul><ul><ul><li>Green laser </li></ul></ul><ul><ul><ul><li>SLG </li></ul></ul></ul>
  46. 46. Spectral confirmation
  47. 47. Spectral confirmation <ul><li>Raman spectrum </li></ul><ul><ul><li>Green laser </li></ul></ul><ul><ul><ul><li>DLG </li></ul></ul></ul>
  48. 48. Spectral confirmation
  49. 49. Spectral confirmation
  50. 50. Spectral confirmation <ul><li>SLG samples </li></ul><ul><ul><li>Red laser </li></ul></ul><ul><ul><ul><li>single peak G’ = 2630 cm -1 </li></ul></ul></ul><ul><ul><ul><li>FWHM = 24 cm -1 </li></ul></ul></ul><ul><ul><ul><li>G’/G ratio >> 1 </li></ul></ul></ul><ul><ul><li>Green laser </li></ul></ul><ul><ul><ul><li>Single peak G’ = 2670 cm -1 </li></ul></ul></ul><ul><ul><ul><li>FWHM = 26 cm -1 </li></ul></ul></ul><ul><ul><ul><li>G’/G ratio >> 1 </li></ul></ul></ul><ul><ul><li>SLG identification complete and identical to literature reviews </li></ul></ul>
  51. 51. Spectral confirmation
  52. 52. Spectral confirmation <ul><li>DLG samples </li></ul><ul><ul><li>Red laser </li></ul></ul><ul><ul><ul><li>G’ peak = 4peaks </li></ul></ul></ul><ul><ul><ul><li>FWHM ≈ 24 cm -1 </li></ul></ul></ul><ul><ul><ul><li>G’/G ratio ≈ 1 </li></ul></ul></ul><ul><ul><li>Green laser </li></ul></ul><ul><ul><ul><li>G’ peak = 4peaks </li></ul></ul></ul><ul><ul><ul><li>FWHM ≈ 24 cm -1 </li></ul></ul></ul><ul><ul><ul><li>G’/G ratio ≈ 1 </li></ul></ul></ul><ul><ul><li>DLG identification complete and identical to literature reviews </li></ul></ul>
  53. 53. Conclusion <ul><li>Step 2: COMPLETE </li></ul><ul><ul><li>Characterization of produced samples </li></ul></ul><ul><ul><ul><li>Non-destructive </li></ul></ul></ul><ul><ul><ul><li>Fast spectra </li></ul></ul></ul><ul><ul><ul><li>Peak-fitting software = reliable results </li></ul></ul></ul><ul><ul><ul><li>SLG / DLG / FLG </li></ul></ul></ul>
  54. 54. Results and discussions <ul><ul><li>Route 1: Supported Graphene </li></ul></ul><ul><ul><li>Deposition Cycle </li></ul></ul><ul><ul><li>Optical Observation </li></ul></ul><ul><ul><li>Spectral Confirmation (deposited samples) </li></ul></ul><ul><ul><li>Transfer </li></ul></ul><ul><ul><li>Route 2 </li></ul></ul>
  55. 55. Transfer <ul><li>Method 1: IPA </li></ul><ul><ul><li>Lifting the “grid/film & flake” off the substrate with IPA </li></ul></ul><ul><ul><li>Unsuccessful so far: </li></ul></ul><ul><ul><ul><li>Grids’ stiffness </li></ul></ul></ul><ul><li>Method 2: KOH </li></ul><ul><ul><li>Etching the SiO 2 layer off </li></ul></ul><ul><ul><li>Unsuccessful so far: </li></ul></ul><ul><ul><ul><li>Flakes swim away </li></ul></ul></ul>
  56. 56. Conclusion <ul><li>Route 1: Supported Graphene </li></ul><ul><ul><li>Step 1: DEPOSITION COMPLETE </li></ul></ul><ul><ul><li>Step 2: CHARACTERIZATION COMPLETE </li></ul></ul><ul><ul><li>Step 3: Transfer incomplete </li></ul></ul>
  57. 57. Results and discussions <ul><ul><li>Route 1 </li></ul></ul><ul><ul><li>Route 2: Free-Standing Graphene </li></ul></ul><ul><ul><li>Characterization </li></ul></ul><ul><ul><li>Transfer </li></ul></ul>
  58. 58. Free-Standing Graphene
  59. 59. Free-Standing Graphene
  60. 60. Free-Standing Graphene
  61. 61. Conclusion <ul><li>FSG characterization COMPLETE </li></ul><ul><ul><li>With both lasers </li></ul></ul><ul><ul><li>Similar results to supported graphene </li></ul></ul><ul><ul><ul><li>Dirtier (Dband, lots of graphitic dirt) </li></ul></ul></ul><ul><ul><li>With 20X objective = ready-to-load at High Pressure </li></ul></ul>
  62. 62. Results and discussions <ul><ul><li>Route 1 </li></ul></ul><ul><ul><li>Route 2: Free-Standing Graphene </li></ul></ul><ul><ul><li>Characterization </li></ul></ul><ul><ul><li>Transfer </li></ul></ul>
  63. 63. Transfer <ul><li>Samples size reduction: IN PROGRESS </li></ul><ul><ul><li>First cuts successful, without damage/alteration </li></ul></ul><ul><ul><li>Down to 100 µm so far </li></ul></ul><ul><ul><li>FS SLG damaged </li></ul></ul>
  64. 64. Transfer
  65. 65. Conclusion <ul><li>Route 2: Free-Standing Graphene </li></ul><ul><ul><li>Step 1: CHARACTERIZATION COMPLETE </li></ul></ul><ul><ul><ul><li>SLG available for transfer </li></ul></ul></ul><ul><ul><ul><li>DLG is missing as a free-standing sample </li></ul></ul></ul><ul><ul><li>Step 2: Transfer incomplete </li></ul></ul>
  66. 66. Summary of Conclusions Route 1: Supported Graphene Route 2: Free-Standing Graphene
  67. 67. Summary of Conclusions <ul><li>Synthesis of target samples COMPLETE </li></ul><ul><ul><li>Supported SLG / DLG </li></ul></ul><ul><ul><ul><li>“ tape” method </li></ul></ul></ul><ul><ul><ul><li>Fast, reproducible, reliable </li></ul></ul></ul><ul><ul><li>Free-Standing SLG available </li></ul></ul><ul><li>Characterization of available samples COMPLETE </li></ul><ul><ul><li>Supported SLD / DLG / 3LG </li></ul></ul><ul><ul><li>Free-Standing SLG </li></ul></ul>
  68. 68. Future Work <ul><li>Synthesis </li></ul><ul><ul><li>Get Free-Standing DLG </li></ul></ul><ul><ul><li>Optimizing the deposition cycle </li></ul></ul><ul><li>Characterization </li></ul><ul><ul><li>Correlate spectra with AFM measurements </li></ul></ul><ul><li>Transfer </li></ul><ul><ul><li>Complete loading for both routes </li></ul></ul>
  69. 69. Future Work Gband 1580cm -1 (intensity a.u.) G’band 2670cm -1 (intensity a.u.) Gband G’band
  70. 70. Acknowledgements <ul><li>Pr Alexander SOLDATOV </li></ul><ul><ul><li>Supervisor, LTU </li></ul></ul><ul><li>Dr Kostya NOVOSELOV </li></ul><ul><ul><li>University of Manchester (UK) </li></ul></ul><ul><li>My saviors </li></ul><ul><ul><li>Zoubir Ayadi, EEIGM (France) </li></ul></ul><ul><ul><li>Lennart Wallström, LTU </li></ul></ul><ul><li>My colleagues </li></ul><ul><ul><li>Dr Shujie You </li></ul></ul><ul><ul><li>Illya Dobryden, PhD </li></ul></ul><ul><ul><li>Murat Özturk, project student </li></ul></ul><ul><ul><li>Johnny Grahn, Johanne Mouzon Nils Almqvist </li></ul></ul><ul><ul><li>David Olevik & Mattias Mases </li></ul></ul>
  71. 71. Thank you for your attention Please address your questions NOW !

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