Realizing single-layer graphene by simultaneous crystallization and top-down etching of amorphous graphene-like carbon obtained via CVD

Continuous large-area graphene can be obtained on copper by utilizing solid polymer carbon sources (SPCS). However, the detailed conversion process and related mechanisms have been rarely reported. Here, a low temperature chemical vapor deposition (CVD) combined with high-temperature hydrogen annealing (HTHA) method is designed to investigate the intricate evolution process from SPCS to amorphous graphene-like carbon (AGLC), and subsequently to single-layer graphene (SLG). During low-temperature CVD process, under catalysis of copper and auxiliary catalysis of hydrogen, the pyrolysis products of SPCS undergo nucleation and growth on copper, resulting in the formation of AGLC at 500 degrees C. During subsequent HTHA process above 1000 degrees C, the conversion of AGLC to continuous SLG can be achieved through simultaneous catalytic crystallization of copper and top-down etching of hydrogen, which sequentially undergoes coexistence stage of AGLC/few-layer graphene (FLG), followed by FLG formation stage. Under different stage and conditions, there exists a synergistic competitive relationship between catalytic effect of copper and etching effect of hydrogen. The proposed conversion mechanism can provide fundamental insights into SLG synthesis via SPCS, which could facilitate further advancements in large-scale industrial applications of graphene.