Berlin 2012 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
O: Fachverband Oberflächenphysik
O 65: Graphene V
O 65.3: Talk
Thursday, March 29, 2012, 11:00–11:15, MA 041
Local tunneling spectroscopy of the Hydrogen-induced impurity state in quasi-freestanding graphene — •Ronny Schlegel1, Martha Scheffler1, Danny Haberer1, Rico Pohle1, Torben Hänke1, Alexander Grüneis1,2, Christian Hess1, and Bernd Büchner1 — 1Leibniz Institute for Solid State and Materials Research Dresden — 2University of Vienna, Austria
Graphene has a unique electronic structure, which is expected to exhibit a linear dispersion near the Fermi edge. Usually this peculiar feature is difficult to observe due to proximity effect from the substrate. However, the fabrication of quasi-freestanding graphene on specific multi-layer metal surfaces has recently been demonstrated.
Manipulation of such graphene through selective insertion of impurities may allow to tune the electronic structure and thus to open up new routes towards graphene based device functionalities. Hydrogenation leads to a reversible gap opening at the Fermi edge. Also a dispersionless, hydrogen-induced state appears in the center of this gap.
Here we use scanning tunneling microscopy and spectroscopy (STM/STS) to study graphene samples with an outstanding cleanness obtained by in-situ preparation under UHV conditions. The surfaces are investigated by STM and atomically resolved images of the pristine graphene as well as the hydrogen adsorbate sites were achieved. STS measurements reveal an enhanced DOS near the Fermi edge after hydrogenation, consistent with theoretical predictions and ARPES experiments.