CHARACTERISATION OF AD-ATOMS AND AD-MOLECULES ON GRAPHENE
Achieving n-, p-type stable doping of graphene is being investigated for different metal dopants, particularly for Hg single atoms and the (easily made) stable linear HgO2 molecule. Several configurations of freestanding Hg and HgO2 molecules with respect to the graphene surface were analysed with Density Functional Theory (DFT). In parallel Perturbed Angular Correlation experiments were performed with 199mHg obtaining the experimental hyperfine fields characterising a specific Hg–... HgO2 ad-atom or ad-molecule configuration on the graphene layer. Among a multitude of possible configurations, the free O-Hg-O dumbbell lying in-plane with the Hg atom above the hollow site (in the centre of the C-hexagon) with oxygen bonds aligned along the C-C bonds, uniquely fit the PAC experimental results.