Epitaxial graphene grown on single crystal Cu(111) foils by chemical vapor deposition is found to be free of wrinkles and under biaxial compressive strain. The compressive strain in the epitaxial regions (0.25–0.40%) is higher than regions where the graphene is not epitaxial with the underlying surface (0.20–0.25%). This orientation‐dependent strain relaxation is through the loss of local adhesion and the generation of graphene wrinkles. Density functional theory calculations suggest a large frictional force between the epitaxial graphene and the Cu(111) substrate, and this is therefore an energy barrier to the formation of wrinkles in the graphene. Enhanced chemical reactivity is found in epitaxial graphene on Cu(111) foils as compared to graphene on polycrystalline Cu foils for certain chemical reactions. A higher compressive strain possibly favors lowering the formation energy and/or the energy gap between the initial and transition states, either of which can lead to an increase in chemical reactivity.

中文翻译：

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Cu（111）箔上石墨烯的取向依赖性应变弛豫和化学功能化

发现通过化学气相沉积法在单晶Cu（111）箔上生长的外延石墨烯无皱纹且处于双轴压缩应变下。外延区域的压缩应变（0.25–0.40％）高于石墨烯与下表面不外延的区域（0.20–0.25％）。这种与方向有关的应变松弛是通过失去局部粘着力和产生石墨烯皱纹来实现的。密度泛函理论计算表明，外延石墨烯与Cu（111）衬底之间存在很大的摩擦力，因此这是石墨烯中形成褶皱的能量屏障。对于某些化学反应，与多晶Cu箔上的石墨烯相比，Cu（111）箔上的外延石墨烯具有增强的化学反应活性。