Graphene films grown by chemical vapour deposition have unusual physical and chemical properties that offer promise for applications such as flexible electronics and high-frequency transistors^{1,2,3,4,5,6,7,8,9,10}. However, wrinkles invariably form during growth because of the strong coupling to the substrate, and these limit the large-scale homogeneity of the film^{1,2,3,4,11,12}. Here we develop a proton-assisted method of chemical vapour deposition to grow ultra-flat graphene films that are wrinkle-free. Our method of proton penetration^{13,14,15,16,17} and recombination to form hydrogen can also reduce the wrinkles formed during traditional chemical vapour deposition of graphene. Some of the wrinkles disappear entirely, owing to the decoupling of van der Waals interactions and possibly an increase in distance from the growth surface. The electronic band structure of the as-grown graphene films shows a V-shaped Dirac cone and a linear dispersion relation within the atomic plane or across an atomic step, confirming the decoupling from the substrate. The ultra-flat nature of the graphene films ensures that their surfaces are easy to clean after a wet transfer process. A robust quantum Hall effect appears even at room temperature in a device with a linewidth of 100 micrometres. Graphene films grown by proton-assisted chemical vapour deposition should largely retain their intrinsic performance, and our method should be easily generalizable to other nanomaterials for strain and doping engineering.

通过化学气相沉积生长的石墨烯薄膜具有不同寻常的物理和化学特性，为柔性电子和高频晶体管等应用提供了希望^{1,2,3,4,5,6,7,8,9,10}。^{然而，由于与基板的强耦合，在生长过程中总会形成皱纹，这些限制了薄膜1、2、3、4、11、12}的大规模均匀性。在这里，我们开发了一种质子辅助化学气相沉积方法来生长无皱的超平坦石墨烯薄膜。我们的质子穿透方法^{13,14,15,16,17}和重组形成氢气也可以减少石墨烯在传统化学气相沉积过程中形成的皱纹。由于范德华相互作用的去耦以及与生长表面的距离可能增加，一些皱纹完全消失。生长的石墨烯薄膜的电子能带结构显示出V形狄拉克锥和在原子平面内或跨原子台阶的线性色散关系，证实了与衬底的去耦。石墨烯薄膜的超平特性确保其表面在湿转移过程后易于清洁。即使在室温下，线宽为 100 微米的器件也会出现强大的量子霍尔效应。通过质子辅助化学气相沉积生长的石墨烯薄膜应在很大程度上保持其固有性能，