Domain Structure and Boundary in Single-Layer Graphene Grown on Cu(111) and Cu(100) Films

Size, orientation, and boundary of graphene domains are the current focus of chemical vapor deposition (CVD) growth because they are closely related to graphene's physical properties. Here, we study the domain structure of single-layer graphene grown by ambient pressure CVD over heteroepitaxial Cu(111) and Cu(100) films. Low energy electron microscope measurements reveal that the Cu(111) film gives uniform single-layer graphene whose orientation is consistent with the underlying Cu lattice for areas over 1 mm(2). On the other hand, single-layer graphene grown on Cu(100) film exhibits clear multidomain structure with two main orientations rotated by 30 degrees. Moreover, a weak Raman D-band is observed along the domain boundaries for, the graphene grown on the Cu(100). Our results give new insights into the growth mechanism of CVD-grown graphene over Cu metals and offer a new direction for the realization of single-crystalline graphene.