Controlled Modulation of Electronic Properties of Graphene by Self-Assembled Monolayers on SiO2 Substrates

In this study, with self-assembled monolayers (SAMs) of aminopropyl-, ammoniumpropyl-, butyl-, and 1H,1H,2H,2H-perfluorooctyltriethoxysilanes deposited in-between graphene and the SiO2 substrate, a controlled doping of graphene was realized with a threshold voltage ranging from -18 to 30 V. In addition, the SAMs are covalently bonded to the SiO2 surface rather than the graphene surface, thereby producing minimal effects on the mobility of the graphene. Finally, it is more stable than conventional noncovalent dopants.