Segregated graphene: From controlled growth to photocatalytic paper-cutting electronics

Graphene is one of the most exciting materials being investigated today due to its incredible electronic, thermal and mechanical performances. Despite the great efforts on its growth technique, it is still a bottleneck challenge to achieve wafer-size graphene with acceptable uniformity and low cost, which would undoubtedly determine the future of graphene electronics. We present herein a universal segregation growth technique for batch production of high-quality wafer-scale graphene from non-noble metal films containing trace amounts of carbons. Based on the well-known “troublesome” segregation phenomenon encountered in metallurgy, 4 inch graphene wafers have been grown from Ni, Co, Fe, Cu-Ni alloy via thermal annealing without using any extraneous carbon source. This segregation growth approach has great advantages over CVD technique at the excellent uniformity, layers controllability and unlimited scalability. We demonstrate the first example of monolayer and bilayer graphene wafers by combining the distinct segregation performances of Cu and Ni. Together with the easy detachment from growth substrates, we believe this facile segregation technique will offer a great driving force for graphene research.