Charge transport properties of interstitially doped graphene: a first-principles study

The role of interstitial atomic doping on transport properties of graphene was systematically studied using first-principles density functional theory (DFT). The study revealed that interstitial Au doping results in a p-type transfer of holes to graphene as the dopant concentration increases to 25%, with the Dirac point shifting to the Fermi level and localised states of atomic dopants appearing at the Fermi level and at energy of −1 eV. Ca, Ag and Al interstitial doping induces an n-type transfer of electrons to graphene with the Dirac point moving away from the Fermi level and localised states appearing at the Fermi level and at energy levels of ∼2 eV for Ca, around −3.5 eV for Ag, −3.5 eV and ∼1.6 eV for Al. As the dopant concentration increases further to 50%, the number of holes (or electrons) decreases for all dopants, except for Ca, as the localised state at the Fermi level disappears, and the Dirac point returns towards the Fermi level. Our research provides insights into how to reconcile the localised state and the number of charge carriers that play a significant role in the transport properties of interstitial doped graphene.