Single-crystal Cu(111) foil preparation by direct bonding technology

Considering the significant advantages of single-crystal Cu(1 1 1) in the synthesis of 2D materials and many other fields, its controllable preparation has attracted widespread attention. However, the formation of a single-crystal Cu foil has always been hindered by competition among grains with different orientations. Herein, single-crystal Cu(1 1 1) was prepared on the basis of the traditional direct bonding copper method. Cu foil and c-plane sapphire substrate were bonded through Cu2O at high temperature. After the reduction of Cu2O by H2, the surface crystal structure of sapphire will guide Cu to form single-crystal Cu(1 11). The single-crystallinity of Cu(1 1 1) and the specific orientation relationship between Cu(1 1 1) and sapphire were confirmed by LEED and XRD. Furthermore, the growth of high-quality single-crystal graphene was performed on single-crystal Cu(1 11). This work not only facilitates the mass production of 2D materials such as single-crystal graphene, but also provides greater application potential to the direct bonding copper technology and single-crystal Cu.