In the early days of graphene development the first method for producing large area graphene was the thermal decomposition of a silicon carbide (SiC) substrate, either terminated with silicon (Si) or carbon (C). Among the plethora of crystalline structures that SiC can adopt, the 6H- and 4H-SiC configurations are favoured for graphene growth due to their hexagonal symmetry and alternating layers of carbon and silicon. The process entails subjecting the substrate to high temperatures, typically ranging from 1200 to 1600°C.
At the C-terminated surface of SiC, multilayer graphene can form, albeit with limited control over the number of layers or film uniformity. Conversely, the Si-terminated face allows for the controlled growth of monolayer and few-layer graphene, facilitating scalability for large-area production on an insulating SiC substrate. However, the quality and doping of the resultant graphene film are heavily influenced by substrate interactions.
To mitigate this, hydrogen passivation is commonly employed to decouple graphene from the substrate, enhancing electronic quality. Remarkably, graphene grown on SiC exhibits impressive electronic properties, with reported electron mobilities reaching as high as 11000 cm²/(V·s), rendering it suitable for advanced transistor technologies and metrology applications.
Despite these advantages, challenges persist. The insulating nature of the substrate complicates the modification of charge carrier concentration and Fermi energy, essential for unlocking certain graphene properties. Moreover, the production of large SiC crystals required for substrate growth incurs significant costs. Additionally, the inability to reliably detach graphene from the SiC substrate confines this method to laboratory settings, limiting its practical applications.
While graphene synthesis on SiC was a vital stepping stone for the high-quality, large-area production of CVD graphene. If you are interested in large area graphene transfer please check out our manual graphene transfer system.
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