1. Techniques of synthesizing wafer-scale graphene GE Xinyuan 26, Nov. 2014

2. Background about the graphene Exfoliation of graphene Epitaxial growth of graphene CVD of graphene Summary Outline 2

3. Background about graphene 3

4. Exfoliation of graphene 4 Transfer-print method Highly oriented pyrolytic graphite (HOPG) pre-patterned Electrostatic field force introduces a screen effect Overcome the interlayer energy with external force

5. Epitaxial growth of graphene 5 Graphene grown on the hexagonal Si face and C face of silicon carbide (SiC) Thermal treatment of SiC at 1300 ℃ under vacuum, sublimation of the silicon atoms, carbon-enriched surface reorganization and graphitization Surface roughening and deep pits induced wide thickness distribution and lateral extension limitation (annealing in vacuum or Ar at 1670 ℃ ) Self-organized growth of carbon atoms into the graphene structure on substrates with comparable lattice

6. CVD of graphene 6 Cu foil is heated up to 1273K for 1h with 21sccm H 2 at 80mtorr (Cu crystallizes into a particular orientation ) Cu foil is annealing for 30min to reduce the oxide and enlarge the grains 105 sccm CH 4 is added to synthesize the graphene at 500mtorr After growing, Cu foil is cooled at a rate of 373K/min in the CH 4 /H 2 atmosphere. Deposition of hydrocarbon gas (CH 4 ) on the metal substrate (Cu foil as catalyst)

7. CVD of graphene 7 PMMA spun onto the graphene surface (baked at 453K for 5min) Cu etched away (with FeCl 3 ) PMMA/graphene transferred to a target wafer PMMA/graphene/wafer baked to enhance the contact PMMA dissolved away (with acetone) Thermal annealing to remove the PMMA residues Graphene is transferred using a sacrificial PMMA layer

8. Summary 8

9. Reference 9