▎ 摘　　要

Plasma-enhanced chemical vapor deposition (PECVD) has emerged as a potential method for the industrial synthesis of graphene due to its low growth temperature, energy savings and in situ graphene growth. Unlike traditional thermal chemical vapor deposition (TCVD), PECVD usually leads to rapid nucleation and growth of graphene from the promoting effect of plasma on the dissociation of the hydrocarbon precursor, resulting in a significantly higher nucleation density of graphene and small grain size, which reduces its electrical performance. Understanding and controlling graphene nucleation and growth during PECVD are of great significance for the synthesis of high-quality graphene. In this study, we noted that the nucleation density and grain size of graphene were significantly affected by various atmospheric conditions, including the Ar flow, H2/CH4 ratio and pressure. In particular, a higher H2/CH4 ratio notably decreased the nucleation density and enlarged the grain size from the effect of the H2 plasma. Furthermore, we studied the energies of the nucleation density, grain size and growth rate of graphene under various pressures by measuring the activation energy and demonstrated that low pressure and high growth temperature enabled to the growth of graphene with low nucleation and large grain size.