High-quality graphene from the surface of CrFeCoNiC high-entropy alloy

Abstract Graphene has shown many attractive properties while the difficulties in the fabrication of high-quality graphene have been a significant bottleneck in its applications. Here we report the discovery of high-quality graphene obtained from the solidified equiatomic CrFeCoNiC high-entropy alloy. Graphite flakes can be peeled off from the surface of the as-cast CrFeCoNiC high-entropy alloy, and single or multilayer graphene can be further exfoliated. The mechanical properties of the graphene are investigated by an atomic force microscope, and the result confirms the discovery of high-quality graphene. The transmission electron microscopy and Raman spectroscopy are applied to further characterize the quality of the graphene and show that the graphene has high-quality with few defects, comparable to the graphene obtained from highly oriented pyrolytic graphite. The thermodynamic calculation is applied to investigate the solidification process of the high-entropy alloy and reveals the mechanism of the formation of graphite on the surface.