A new direct growth method of graphene on Si-face of 6H-SiC by synergy of the inner and external carbon sources

•The inner and external carbon synergy (IECS) method is designed to grow good quality monolayer graphene on Si-face of 6H-SiC.•Compared with the traditional method, the IECS method possesses both of the advantages of the chemical vapor deposition and traditional epitaxial growth methods, which is helpful for monolayer graphene growth.•The growth period (3min) by IECS method is much lower than that of the traditional EG method, which usually need at least half an hour, and interestingly the growth temperature is ∼200°C lower than the EG process.•The optimum conditions using the IECS method are as follows: annealing temperature 1450°C, methane flow rate 1.5sccm, growth time 3min, and total pressure of 800mbar.