Mechanical Integrity and Reinforcement Efficiency of Graphene Grown on Liquid Copper by Chemical Vapor Deposition

Graphene is a perfect 2D crystal of covalently bonded carbon atoms and constitutes the building block for all graphitic structures. Its superior properties make it an attractive material for a variety of technological applications. However, mass production does not meet the initial expectations. Chemical Vapor Deposition (CVD) is currently the only available method for large-scale automated production, but the produced graphene sheets suffer from structural and morphological defects that degrade considerably the mechanical and other physical properties of synthesized graphene. Recently, the use of liquid metal catalysts (LMCat) has been proposed as an alternative platform for facile and high-quality synthesis of single-crystal graphene. Herein, simultaneous Raman spectroscopy combined with mechanical testing is adopted confirming that the reinforcing efficiency of the LMCat graphene is greatly improved. In fact, the effective Young's modulus of LMCat graphene has been found approximate to 630 GPa, which is significantly higher than the graphene grown on solid Cu substrate due to differences in the morphology of Cu substrate. Overall, this work paves the way for the development of defect-free graphene of quality comparable to exfoliated flakes, and this will have a major technological impact for many applications. Herein, Raman spectroscopy combined with mechanical testing highlights the significantly improved reinforcing efficiency of LMCat graphene owing to variances in the morphology of Cu substrate. An effective Young's modulus of 630 GPa has been calculated notably higher than that of graphene grown on solid Cu, paving the way for the development of high-quality graphene sheets with comparable mechanical performance with the exfoliated flakes. image