On the role of surface migration in the growth and structure of graphene layers Original Research Article

The principle of chemical similarity, postulating analogy of chemical reactions taking place on a graphene edge to those of aromatic species, has lead to the formulation of detailed reaction models for the growth of carbonaceous surfaces. While meeting a reasonable success, for instance in the areas of soot and carbon-black formation, such an analogy-based approach cannot be expected to provide a truly realistic description of surface processes. The primary cause of the possible dissimilarity is the difference in steric confinements of reactive sites. A recent quantum chemical study of possible reaction steps led to a proposed phenomenon of surface migration of five-member rings along an edge of a graphene layer. The migrating ring can either desorb or convert to a six-member ring upon an encounter with another six-member ring or a reaction with a gaseous species. All these processes––migration, desorption, and transformation reactions––are mediated by reactions with gaseous hydrogen atoms. The subject of the present communication is analysis of this coupled phenomenon. We will report the results of new Monte Carlo simulations that examine the interplay among surface migration, gas–surface reactions, desorption, and surface transformation reactions of the five-member rings, focusing on emergent morphologies of graphene layers.