Diamond as an inert substrate of graphene.

Interaction between graphene and semiconducting diamond substrate has been examined with large-scale density functional theory calculations. Clean and hydrogenated diamond (100) and (111) surfaces have been studied. It turns out that weak van der Waals interactions dominate for graphene on all these surfaces. High carrier mobility of graphene is almost not affected, except for a negligible energy gap opening at the Dirac point. No charge transfer between graphene and diamond (100) surfaces is detected, while different charge-transfer complexes are formed between graphene and diamond (111) surfaces, inducing either p-type or n-type doping on graphene. Therefore, diamond can be used as an excellent substrate of graphene, which almost keeps its electronic structures at the same time providing the flexibility of charge doping.