Heterogeneous Solid Carbon Source-Assisted Growth of High-Quality Graphene via CVD at Low Temperatures

Polycyclic aromatic hydrocarbons (PAH) have been widely used as solid carbon sources for the synthesis of graphene at low temperatures. The inevitable formation of structural defects, however, has significantly limited the quality of the synthesized graphene. This article describes a low-temperature chemical vapor deposition method that effectively mitigates defect formation in graphene by heterogeneous solid carbon sources containing a mixture of aromatic and aliphatic carbon on a Cu substrate. The addition of small amount of aliphatic carbon sources to the PAH significantly decreases the defect density of graphene synthesized at 400 T 600 degrees C by incorporating small aliphatic carbon fragments into defect sites. The carrier mobility of graphene grown using this heterogeneous solid carbon source is more than five times that of graphene synthesized using only PAH. Two mechanisms are also proposed by which vacancies can be generated during graphene growth using PAH sources on Cu, defect generation due to the disordered packing and the geometric limitation of PAH molecules. This low-temperature method of synthesizing graphene reduces the degree of defect density using heterogeneous solid carbon sources promises to provide wide utility in electronics applications.