Segregation Growth of Graphene on Cu–Ni Alloy for Precise Layer Control

Abstract

A facile way to segregate wafer-size graphene with controllable layer number using Cu–Ni binary alloy under vacuum annealing condition is presented here. Increasing atomic percentage of Ni in Cu–Ni alloy was found to segregate thicker uniform graphene. To date, over 95% monolayer and 91% bilayer graphene films have been prepared by only changing atomic percentage of Ni in Cu–Ni alloy, respectively. The synergetic combination of the distinct carbon solubilities of Cu and Ni and the well-known segregation phenomenon is believed to be responsible for the formation of high-quality uniform few layer graphene. Together with the easy detachment from growth substrates, we believe this facile segregation technique will offer a great driving force for graphene research.