Lattice Selective Growth of Graphene on Sapphire Substrate

Abstract

In this work, we report a systematic study of CVD synthesizing graphene on different crystal faces of sapphire (c-Plane, m-Plane, and r-Plane). Nickel films are deposited on sapphire substrates with c-Plane, m-Plane, and r-Plane to catalyzing the growth of graphene by CVD (Chemical Vapor Deposition) method. It is only on c-Plane sapphire substrates that graphene can be found after growth and etching off nickel. In the case of m-Plane and r-Plane sapphire substrates, graphene forms only on the top surface of nickel films, but none at the interface between nickel and sapphire. Oxygen plasma treatment is introduced to certify that graphene on c-Plane sapphire does not originate from the top surface of nickel film. Selective formation of graphene is attributed to lattice structures of sapphire’s different faces. Moreover, influences of nickel’s thickness and growth time are studied by a series of control experiments.