Application of Crystal Growth Theory in Graphene CVD Nucleation and Growth

Abstract

Graphene is a star material due to its intriguing electronic, mechanical, thermal and chemical properties and many potential applications. For most of these potential applications, the synthesis of high-quality graphene layers in large scale is highly desired. In the past 10 years, many methods of synthesizing graphene have been developed and explored extensively. Among them, transition metal (TM)-catalyzed chemical vapor deposition (CVD) method stands out for its numerous advantages. As a typical two-dimensional crystal, the growth of graphene must follow the classical crystal growth theory. Here, we introduce three aspects of graphene CVD growth mechanism based on the classical crystal growth theory and the density functional theory (DFT) calculations. (1) The nucleation process and nucleation rate of graphene on metal terrace and near a step edge. On the basis of the predicated very large nucleation barrier, we have proposed a strategy of using the seeded growth method to grow large-area single crystal graphene. (2) Application of Wulff construction in graphene CVD growth. Based on the investigations of graphene edge structures on metal surface and their formation energies, the equilibrium structures of graphene island can be determined by the theory of Wulff construction. (3) The application of kinetic Wulff construction in graphene CVD growth. A detailed investigation on the structural stability and growth kinetics of graphene on the Cu(111) surface have been systematically investigated. According to the kinetic Wulff construction, the armchair edge which growth fast will gradually disappear and the zigzag edges which grows slowly will eventually dominate the circumference of a growing graphene island. The above discussions and conclusions lead to a deep insight into the CVD graphene growth, which are expected to guide the experimental design of growing large-scale graphene with high-quality.