Equal variations of Fermi level and work function in graphene at the nanoscale

Sayanti Samaddar (1) , Johann Coraux (2) , Sylvain Martin (3) , Benjamin Grevin (3) , Hervé Courtois (1) , Clemens Winkelmann (1)

1 NEEL - QuNES - Nano-Electronique Quantique et Spectroscopie
2 NEEL - Quan2m - Interactions modulables dans des états quantiques 2D
3 INAC - Institut Nanosciences et Cryogénie

If surface effects are neglected, any change of the Fermi level in a semiconductor is expected to result in an equal and opposite change of the work function. This is however not observed in general in three-dimensional semiconductors, because of Fermi level pinning at the surface. By combining Kelvin Probe Force Microscopy and Scanning Tunneling Spectroscopy on single layer graphene, we measure both the local work function and the charge carrier density. The one-to-one equivalence of changes in the Fermi level and the work function is demonstrated to accurately hold in single layer graphene down to the nanometer scale.

Domaines: Systèmes mésoscopiques et effet Hall quantique [cond-mat.mes-hall]

Sayanti Samaddar, Johann Coraux, Sylvain Martin, Benjamin Grevin, Hervé Courtois, et al.. Equal variations of Fermi level and work function in graphene at the nanoscale. Nanoscale, 2016, 8 (33), pp.15162. ⟨10.1039/C6NR04606A⟩. ⟨hal-01361998⟩