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Low Temperature Graphene Growth on Nickel Substrates

Low Temperature Graphene Growth on Nickel Substrates. S. A. Giamini. Committee: I. Grammatikakis, K. Simseridis, A. Dimoulas. Graphene. A hexagonal honeycomb lattice of carbon. In its basic form it is a one-atom thick (2D) sheet. Interesting properties:

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Low Temperature Graphene Growth on Nickel Substrates

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  1. Low Temperature Graphene Growth on Nickel Substrates S. A. Giamini Committee: I. Grammatikakis, K. Simseridis, A. Dimoulas

  2. Graphene A hexagonal honeycomb lattice of carbon. In its basic form it is a one-atom thick (2D) sheet. Interesting properties: Better electric conductor than copper, high mobility, ballistic transport, great thermal conductivity, harder than diamond, almost completely transparent and more… Dedkov et. al Epitaxial Graphene on Metals

  3. Motivation Describe methods and techniques that could help graphene integration with IC industry Move towards growing good quality graphene in low temperatures

  4. Approach Growth of graphene on nickel substrates by CVD Switch to lower temperatures for graphene growth Study nickel thickness as a main parameter of produced graphene quality and layer number

  5. Nickel Thickness segregation Surface carbon Graphene Nickel substrate Carbon concentration Diffused carbon in "reservoir" precipitation Graphene Control precipitation: suppress or tune

  6. CVD

  7. Substrate thickness

  8. Raman Spectroscopy - Graphene Ipeak = Area/FWHM I2D/IG : Number of layers ID/IG : Density of defects

  9. Sample1 - Graphene on Ni(111) 10nm / AlN(002) 200nm/Si(111) I2D/IG ~ 1 ID/IG ~ too big Nickel film destroyed

  10. Sample2 - Graphene on Ni(111) 100nm / AlN(002) 200nm/Si(111) Sample3 - Graphene on Ni 100nm / SiO2/Si(100) Growth at 900 ◦C Nickel film non-uniform I2D/IG ~ 1 ID/IG ~ negligible Nickel film destroyed I2D/IG ~ 1 ID/IG ~ very small

  11. Sample4 - Graphene on Ni 400nm / SiO2/Si(100) Growth at 600 ◦C I2D/IG ~ 0.7 ID/IG ~ 0.2 Nickel film Not - destroyed • Two factors in effect: • Lower temperature - activation energy of nucleation sites leading to flake aggregation • Thicker thin film - film preservation and carbon "reservoir" • Sample annealed at 500 ◦C

  12. Sample5 - Graphene on Ni foil 25μm Growth at 600 ◦C I2D/IG ~ 1 I2D/IG ~ 0.5 • Surface measurements give two main types of spectra - not fully uniform coverage • D peak is negligible or very small - low density of defects • Sample annealed at 700 ◦C

  13. Sample6 - Graphene on Ni slab 1mm Growth at 600 ◦C I2D/IG ~ 1.5 ID/IG ~ 0.15 • Best measurements so far – indicative of AB stacking bilayer graphene • D peak is not negligible but small - low density of defects • Small coverage of sample • Sample annealed at 700 ◦C

  14. Important details Nickel foils and slabs that were electropolished produced significantly better results than non-polished. Surface roughness plays an important role. Bulk nickel (25μm foil and 1mm slab) possibly only requires an initial out-of-process cleaning anneal (700 ◦C or higher) allowing for a milder in-process anneal at 600 ◦C or lower. Bulk nickel can be reused if graphene films are removed in a non-destructive manner e.g. electrochemical delamination

  15. Conclusions We can produce graphene on nickel with low temperature growth processes (600 ◦C) and a very low density of defects Nickel as a substrate can act as a "reservoir" due to its high carbon solubility and its thickness can be used to tune graphene growth Target is low-temp / low defect / mm sized graphene for applications in nanoelectronics

  16. THANK YOU FOR YOUR ATTENTION • Indicative bibliography • Zongping Chen et al. CARBON 48 ( 2010 ) 3543 –3550 • Robert S. Weatherup Bruno Dlubak , and Stephan Hofmann. ACS Nano, 2012, 6 (11), pp 9996–10003 • Yu Wang et al. ACS Nano, 2011, 5 (12), pp 9927–9933 • Gwan-Hyoung Lee et al. Science 340, 1073 (2013) • M.Sarno, C.Cirillo, R.Piscitelli, P.Ciambelli, J. Mol. Catal. A: Chem. 366 (2013) 303–314 • Kwanpyo Kim, et al. Phys. Rev. Lett. 108, 246103 (2012) • Alfonso Reina, et al. Nano Lett., 2009, 9 (1), pp 30–35. • Robert S. Weatherup, Bruno Dlubak , and Stephan Hofmann, ACS Nano, 2012, 6 (11), pp 9996–10003

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