Graphene layers grown on metallic substrates by chemical vapor deposition generally exhibit wrinkles due to mismatches in thermal expansion coefficients of the graphene and the substrates, which affect remarkably the tribological, mechanical and electrical properties of graphene-based devices. Here we report an isotropic-stretching method to eliminate these wrinkles. The morphology evolution of the wrinkles during the stretching process is studied using an atomic force microscope, and a simple method for calculating the critical strain required to eliminate the wrinkles is suggested. Friction and scratching tests demonstrate that for graphene layers the friction and anti-wear performances of regions with eliminated pre-existing wrinkles are as good as the wrinkle-free regions. Our method is expected to be applicable to other layered materials grown on deformable surfaces.

通过化学气相沉积在金属基板上生长的石墨烯层通常会出现皱纹，这是由于石墨烯与基板的热膨胀系数不匹配而引起的，这显着影响了石墨烯基器件的摩擦学，机械和电性能。在这里，我们报告了一种各向同性的拉伸方法来消除这些皱纹。使用原子力显微镜研究了拉伸过程中皱纹的形态演变，并提出了一种简单的方法来计算消除皱纹所需的临界应变。摩擦和划痕测试表明，对于石墨烯层，消除了先前存在的褶皱的区域的摩擦和抗磨性能与无褶皱的区域一样好。