Band gap characteristics. Modeled 33-atom single layer of graphite with silver atoms adsorbed on different sites (center; T, ontop; H, hollow; and B, bridge). Band gap characteristics of (a) pristine graphene, (b) Ag atom on top sites, (c) Ag atom on hollow sites, and (d) Ag atom on bridge sites, respectively. Nothing significant for Ag on top of C, but the introduction of Ag on the bridge site (c) resulted in the disappearance of the silver signature around the Fermi level, and less significant peaks are observed very far from the Fermi level (around -0.55 eV) in the valence band region. The legends s, p, d, f and sum represents electronic energies from the s, p, d, and f orbitals, respectively, and sum represents the overall/total contribution, in other words, Es + Ep + Ed + Ef = Esum, where E represents the respective energies.
Ndlovu et al. Nanoscale Research Letters 2012 7:173 doi:10.1186/1556-276X-7-173