▎ 摘　　要

A thermal expansion mismatch is inevitable for graphene grown on various substrates by chemical vapor deposition, which leads to the formation of wrinkles during post-growth cooling. Wrinkles can degrade the superior properties of graphene and increase device-to-device inconsistency. To address this issue, wrinkle-free graphene patterns are grown on Ge(110) substrate with the assistance of 5 x 10(16) cm(-2) Si ion implantation. The experimental data show that the wrinkle-free graphene can grow on unimplanted areas, whereas no graphene is synthesized on Si ion implanted areas. Further research shows that the wrinkle-free nature of graphene is closely related to the compressive strain distribution in graphene. The compressive strain in graphene is increased to a significant extent with an increase in the size of graphene patterns. When the compressive strain energy exceeds the wrinkle-formation barrier, wrinkles emerge on the graphene, and the compressive strain decreases as a consequence. This research may help to understand the formation mechanisms of graphene wrinkles and promote the growth of wrinkle-free graphene.