Multiple graphene synthesis from pre-dissolved carbon resource in CuNi alloy

Graphene thin films (1-3 layers) were successfully synthesized multiple times on the surface of CuNi alloy through repeated annealing of the metal catalyst after a single chemical vapor deposition (CVD) process. First, graphene was grown by CVD method on CuNi catalyst substrates. Second, the same CuNi catalyst foils were annealed in absence of any external carbon precursor to grow graphene using the pre-dissolved carbon atoms in the catalyst. This annealing process was repeated for 5 times to synthesize graphene successfully until the carbon atoms in the catalyst foils were exhausted. After the CVD growth and each annealing process, the as-grown graphene was removed using bubbling method. A wide range of characterization methods were used to prove the presence and examine the quality of the obtained graphene films. This new method to synthetize graphene provided overall homogeneous films made by 1-3 atomic layers. Graphene from each annealing process resulted of similar quality confirming high reproducibility of the method. This technique brings more freedom to graphene growth and applications, and could be useful also for other material synthesis.