| AVS 65th International Symposium & Exhibition | |
| Surface Science Division | Thursday Sessions |
| Session SS+EM+NS-ThM |
| Session: | Defects in and Functionalization of 2D Materials |
| Presenter: | Patricia A. Thiel, Ames Laboratory and Iowa State University |
| Authors: | A. Lii-Rosales, Ames Laboratory and Iowa State University S. Julien, Northeastern University Y. Han, Ames Laboratory and Iowa State University J.W. Evans, Ames Laboratory and Iowa State University K.-T. Wan, Northeastern University P.A. Thiel, Ames Laboratory and Iowa State University |
| Correspondent: | Click to Email |
Deposition of Cu on a sputtered graphite surface, in ultrahigh vacuum, can be manipulated to produce buried islands of metallic, multilayer Cu. The Cu islands are covered by a graphitic layer consisting of several graphene sheets. This layer drapes like a tarpaulin over the Cu islands. We have observed flat-topped islands as tall as 40 nm and as wide as 600 nm. One of the most striking features of island geometry is the fact that the slope of the tarpaulin at the sides of the islands is invariant over a wide range of island volumes. The variation of the ratio of island diameter to height as a function of island volume is far less regular in the experimental data, suggesting that kinetic limitations may play a role in determining this parameter. To investigate the physical forces responsible for the island geometries, we develop a model for island shape that incorporates the distortion energy of graphene, adhesion of Cu with graphitic surfaces, adhesion of graphene with graphite, and other parameters. The energy parameters involving Cu surfaces and Cu-carbon interfaces are derived from DFT calculations. The values and trends predicted by the model are discussed and compared with experiment. In particular, the model indicates that the slope of the island sides should be invariant, consistent with experiment.