Suppression of graphene nucleation by plasma treatment of Cu foil for the rapid growth of large-size single-crystal graphene

Abstract

Chemical vapor deposition (CVD) method generally used for the fabrication of single-crystal graphene is still imperfect in the suppression of nucleation density, which is detrimental to the domain size of single-crystal graphene to a great extent. Herein, we have successfully developed a new strategy to realize the controllable nucleation by the plasma treatment of Cu foil, and carry out the rapid growth of single-crystal graphene, combined with the program heating and concentration gradient growth method during the CVD-grown stage. The plasma treatment can effectively remove impurities of Cu foil surface, which reduces the active sites for single-crystal graphene nucleation. Meanwhile, CuO nanoparticles are formed on the Cu foil surface by the plasma treatment, which can be reduced and produce oxygen after annealing at high temperature in H2 atmosphere to promote the rapid growth of graphene and suppress graphene nucleation. Eventually, we have achieved the synthesis of hexagon-shaped single-crystal graphene with the low defects, large-size of ∼5 mm, fast growth rate of 2.5 mm h−1, high uniformity (monolayer coverage of ≥90%) and high field-effect mobility of ≥12,500 cm2 V−1 s−1. Our work provides a facile and effective method for the fabrication of large-size single-crystal graphene, paving the way towards future potential applications of single-crystal graphene in the industrial level.