▎ 摘　　要

We observed in situ growth of a single graphene sheet on Ni(111) by low-energy electron microscopy. The sheet was grown epitaxially beyond the steps on the substrate. The crystalline shapes of graphene islands were clearly seen; the straight edges of the island are crossed at either 60 or 120 degrees, and the linear edges shifted perpendicular to the edge keeping the equilibrium shape. Graphene islands were united to form a single sheet without any grain boundaries and any wrinkles. The Ni substrate of several centimeters in size was covered with a single-domain graphene sheet. Copyright (C) 2011 John Wiley & Sons, Ltd.