Gate-controlled electron transport in coronenes as a bottom-up approach towards graphene transistors

Graphene is considered to be a large aromatic molecule, the limiting case of the family of polycyclic aromatic hydrocarbons. This fascinating two-dimensional material has many potential applications, including field effect transistors (FETs). However, the graphene sheets in these devices have irregular shapes and variable sizes, and contain various impurities and defects, which are undesirable for applications. Moreover, the bandgap of graphene is zero and, consequently, the on/off ratios of graphene FETs are small, making it difficult to build logic circuits. To overcome these difficulties, we report here a bottom-up attempt to fabricate nanoscale graphene FETs. We synthesize structurally well-defined coronene molecules (consisting of 13 benzene rings) terminated with linker groups, bridge each molecule to source and drain electrodes through the linkers, measure conductance and demonstrate the FET behaviour of the molecule.