Effect of Staged Methane Flow on Graphene Quality of Low-Pressure Chemical Vapor Deposition

Abstract

The chemical vapor deposition method and the method using copper are suitable for high-quality large-area graphene synthesis. Here, we present methane flow conditions for obtaining high-quality graphene over a large area. The conditions of gases other than the flow rate of methane were fixed, and the graphene synthesized by adjusting the flow rate of methane and the exposure time of methane was verified through the Raman spectrum. When the methane flow rate was 5 sccm, the growth of graphene was island-shaped and made into a multilayer graphene. When the methane flow rate increases to 8 sccm, the Irish growth of graphene disappears and stably grows into a single layer. However, if the flow rate exceeds 9 sccm, Irish growth disappears. However, in order to minimize the area where graphene in the multilayer is synthesized, the methane exposure time was analyzed in units of 10 minutes from 5 minutes to 25 minutes. When analyzing the I[2d]/I[g] value and I[d]/I[g] value of the Raman spectrum, single-layer graphene of a large area could be observed.