Enhancing controllability and stability of bottom-gated graphene thin-film transistors by passivation with methylamine

This paper is intended to aid to bridge the gap between chemistry and electronic engineering. In this work, the fabrication of chemical vapour deposited graphene field-effect transistors employing silicon-nitride (Si3N4) gate dielectric is presented, showing originally p-type channel conduction due to ambient impurities yielding uncontrollable behaviour. Vacuum annealing has been performed to balance off hole and electron conduction in the channel, leading to the observation of the Dirac point and therefore improving controllability. Non-covalent functionalisation by methylamine has been performed for passivation and stability reasons yielding electron mobility of 4800 cm(2)/V s and hole mobility of 3800 cm(2)/V s as well as stabilised controllable behaviour of a bottom-gated transistor. The introduction of interface charge following the non-covalent functionalisation as well as the charge balance have been discussed and analysed. (C) 2014 AIP Publishing LLC.