TY - JOUR
T1 - Electronic structure of graphene on a reconstructed Pt(100) surface
T2 - Hydrogen adsorption, doping, and band gaps
AU - Ulstrup, S.
AU - Nilsson, L.
AU - Miwa, J.A.
AU - Balog, R.
AU - Bianchi, M.
AU - Hornekær, L.
AU - Hofmann, P.
PY - 2013/9/19
Y1 - 2013/9/19
N2 - We probe the structure and electronic band structure of graphene grown on a Pt(100) substrate using scanning tunneling microscopy, low energy electron diffraction, and angle-resolved photoemission spectroscopy. It is found that the graphene layer lacks a well-defined azimuthal orientation with respect to the substrate, causing a circular smearing of the π band instead of a well-defined Dirac cone near the Fermi level. The graphene is found to be electron doped placing the Dirac point ∼0.45 eV below the Fermi level, and a gap of 0.15±0.03 eV is found at the Dirac point. We dose atomic hydrogen and monitor the coverage on the graphene by analyzing the impurity-induced broadening of the π-band width. Saturation of graphene on Pt(100) with hydrogen does not expand the band gap, but instead hydrogen-mediated broadening and rehybridization of the graphene sp2 bonds into sp3 leads to a complete disruption of the graphene π band, induces a lifting of the Pt(100) reconstruction, and introduces a dispersing Pt state near the Fermi level. Deposition of rubidium on graphene on Pt(100) leads to further electron doping, pushing the Dirac point to a binding energy of ∼1.35 eV, and increasing the band gap to 0.65±0.04 eV.
AB - We probe the structure and electronic band structure of graphene grown on a Pt(100) substrate using scanning tunneling microscopy, low energy electron diffraction, and angle-resolved photoemission spectroscopy. It is found that the graphene layer lacks a well-defined azimuthal orientation with respect to the substrate, causing a circular smearing of the π band instead of a well-defined Dirac cone near the Fermi level. The graphene is found to be electron doped placing the Dirac point ∼0.45 eV below the Fermi level, and a gap of 0.15±0.03 eV is found at the Dirac point. We dose atomic hydrogen and monitor the coverage on the graphene by analyzing the impurity-induced broadening of the π-band width. Saturation of graphene on Pt(100) with hydrogen does not expand the band gap, but instead hydrogen-mediated broadening and rehybridization of the graphene sp2 bonds into sp3 leads to a complete disruption of the graphene π band, induces a lifting of the Pt(100) reconstruction, and introduces a dispersing Pt state near the Fermi level. Deposition of rubidium on graphene on Pt(100) leads to further electron doping, pushing the Dirac point to a binding energy of ∼1.35 eV, and increasing the band gap to 0.65±0.04 eV.
UR - http://www.scopus.com/inward/record.url?scp=84884867498&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.88.125425
DO - 10.1103/PhysRevB.88.125425
M3 - Journal article
AN - SCOPUS:84884867498
SN - 2469-9950
VL - 88
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 12
ER -