1. Introduction SiC substrate Process Expitaxial graphene on Si – face Expitaxial graphene on C – face Summary Graphene synthesis on SiC

2. Graphene synthesis methods Graphene Synthesis Top down Bottom Up Mechanical exfoliation Chemical exfoliation Chemical synthesis Pyrolysis Epitaxial Growth CVD Other methods

3. Epitaxial growth Single crystalline film on a single crystalline substrate. SiC substrate graphene Feasibility and scalability High temperature process, difficult graphene transfer from SiC to other sub, expensive substrate. Anneal Si

4. SiC substrate Hexagonal polytypism. (4H, 6H) 3 carbon – 1 Si ( bilayer ) – 1 carbon linking another layer Polar: Si – face (0001), C – face (000ī) A B C B

5. Surface cleaning ( H2 etching, furnace, Ar + H2, ~1 atm ) or CMP Surface oxide removing ( heating ~1000°C, UHV, Si flux )  SiO gas Graphene formation - UHV, high temp - Ar overpressure, more high temp Process

6. Si – face (0001) Unit vector: SiC 3.08A, graphene 2.46A Rotating 30°C formation to align First graphene layer covalent bonding with Si. Structural graphene but no electrical property (ZLG)

7. From 2 nd graphene layer (MLG), forming π bonding. Intrinsic doping n~10^13 due to the ZLG-SiC interface. Bilayer intrinsic doping and band gap opening Si – face (0001)

8. Transfer doping - Deposit electron acceptor - ex. Antimony, bismuth, F4-TCNQ ( electron acceptor molecule. Intercalation - Decoupling ZLG from SiC by putting other Si – face (0001)

9. Rotating 30° or ± 2.2° [10ī0] formation. Electrically decoupled between layers Stacks of layer  single layer electronic properties. C – face (000ī)

10. Si – faceC - face -Uniform single layer thickness control ( Ar overpressure ) -No effect of Ar overpressure -Uniformity control difficult -Defect free from SIC substrate-Surface defect -High crystal quality-Process control difficult -2000 cm2/VS (N-doped) -30000 cm2/VS (charge-neutral) -5000 cm2/VS (N-doped) -150,000 cm2/VS (charge-neutral) SUMMARY

11. J. Hass, et al. PRL 100, 125504 (2008) C. Riedl, et al. J. Phys. D: Appl. Phys. 43 (2010) 374009 Zachary R. Robinson, et al. CARBON 81 (2015) 73-82 J. Hass, et al. J. Phys: Condens. Matter 20 (2008) 323202 U. Starke, et al. MRS Bulletin 37 (DEC. 2012) Phillip N. First, et al. MRS Bulletin 35 (APR. 2010) Reference