Electron-state engineering of bilayer graphene by ionic molecules

Abstract

Based on the first-principles total-energy calculations, we demonstrate the possibility of controlling the band-gap and carrier type of bilayer graphene using ionic molecules. Our calculations suggest that bilayer graphene sandwiched by a pair of cation-anion molecules is a semiconductor with a moderate energy gap of 0.26 eV that is attributable to the strong local dipole field induced by the cation-anion pair. Furthermore, we can control the semiconducting carrier type-intrinsic, p-type, or n-type-of bilayer graphene sandwiched by ionic molecules by changing the cation-anion pair. © 2012 American Institute of Physics.