Graphene Nucleation Preference at CuO Defects Rather Than Cu 2 O on Cu(111): A Combination of DFT Calculation and Experiment.

It is well-known that reducing the nucleation density is an effective way to enhance the growth quality of graphene. In this work, we explore the mechanism of graphene nucleation and growth around CuO defects on a Cu(111) substrate by using density functional theory (DFT) combined with the nudged elastic band (NEB) method. The defect formation mechanism at the initial nucleation stage is also studied. Our calculation results of the C adsorption energy and the reaction barrier of C-C dimer formation illustrate that the initial nucleation of graphene could be promoted by artificially introducing CuO defects on a Cu(111) surface and the nucleation on the clean Cu(111) substrate could thus be suppressed. These conclusions have been verified by graphene growth experiments using a chemical vapor deposition (CVD) method. Further studies showed that graphene grown around CuO "seed crystals" could maintain its structural integrity without significantly producing defective carbon rings. This work provides fundamental understanding and theoretical guidance for controllable preparing large dimension and high quality graphene by artificially introducing CuO seeds.