Molecular beam epitaxial growth of graphene using cracked ethylene — Advantage over ethanol in growth

We studied the growth of graphene by molecular beam epitaxy (MBE) using ethylene and evaluated the MBE-grown graphene. The flow rate dependence of the carbon deposition rate in the ethylene MBE indicated a gradual decrease of the deposition rate with increasing flow rate. This is an improvement from that deposition rate with ethanol, which abruptly decreases because of an etching effect. This feature of ethylene enhances the condition for the growth of the high-quality graphene. Raman spectroscopy measurement and atomic force microscopy observation show that the quality of graphene grown using ethylene is improved from that grown using ethanol from the viewpoints of a domain size and crystallinity. These results demonstrate the advantages of ethylene over ethanol in the MBE growth of graphene.