Toward controllable CVD synthesis of graphenes on copper substrates: roles of oxygen species

Abstract

Oxygen-assisted and oxygen-containing species-assisted chemical vapour deposition (CVD) has emerged as a promising method for the controllable growth of graphenes on copper foil. However, existing reports are limited to individual CVD stages and lack in-depth analysis. This review systematically highlights the roles of oxygen and oxygen-containing species in the entire CVD growth of graphenes on copper foil. First of all, the sources and compositions of oxygen-containing species and copper oxides are unraveled. Following the sequence of the CVD process, the complicated chemical interaction between O, C, H and Cu elements involved in the CVD system is emphasized to thoroughly collate the influence of oxygen-containing species on the surface cleaning, surface morphology, and crystallographic characteristics of Cu foil prior to growth. Subsequently, we comprehend their functions in the decomposition and diffusion of carbon precursors, as well as alterations in nucleation mechanisms. Finally, considering the catalyzing and templating roles of copper oxides or hetero-structured copper oxides/copper surfaces, we analyse the kinetics growth control over the morphology, layer number, lattice orientation, twist angle, flatness, and defect healing of graphenes, governing their electronic structure and intrinsic properties. This review contributes to a mechanistic understanding of oxygen-assisted CVD for advancing the controllable synthesis strategies.