Tunable Band Gaps and p-Type Transport Properties of Boron-Doped Graphenes by Controllable Ion Doping Using Reactive Microwave Plasma

We report tunable band gaps and transport properties of B-doped graphenes that were achieved via controllable doping through reaction with the ion atmosphere of trimethylboron decomposed by microwave plasma. Both electron energy loss spectroscopy and X-ray photoemission spectroscopy analyses of the graphene reacted with ion atmosphere showed that B atoms are substitutionally incorporated into graphenes without segregation of B domains. The B content was adjusted over a range of 0–13.85 atom % by controlling the ion reaction time, from which the doping effects on transport properties were quantitatively evaluated. Electrical measurements from graphene field-effect transistors show that the B-doped graphenes have a distinct p-type conductivity with a current on/off ratio higher than 102. Especially, the band gap of graphenes is tuned from 0 to ∼0.54 eV with increasing B content, leading to a series of modulated transport properties. We believe the controllable doping for graphenes with predictable transport...