Local work function measurements of plasma-fluorinated epitaxial graphene

Sonam Sherpa (1) , Jan Kunc (2) , Yike Hu (2) , Galit Levitin (1) , Walt A de Heer (2) , Claire Berger (3) , Dennis Hess (1)

1 School of Chemical and Biomolecular Engineering [Atlanta]
2 School of Physics
3 NEEL - QuantECA - Circuits électroniques quantiques Alpes

Plasma-fluorination is an attractive route toward the work function engineering of graphene. The effect of surface topography of epitaxial graphene grown on silicon carbide on the increase in work function after plasma-fluorination was investigated using scanning Kelvin probe microscopy. Results of these studies demonstrate the ability of plasma-treatments to functionalize epitaxial graphene without significant surface roughening. For few-layer epitaxial graphene on the Si-face, work function distribution corresponds to its surface topography. A bimodal distribution is observed before and after fluorination and the separation between the two modes widens after the fluorination. For multi-layer epitaxial graphene on the C-face, no correlation is observed between the work function distribution and the surface topography. After fluorination, the work function is fairly uniform except in few peeled off areas that show a stronger work function contrast.

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

Sonam Sherpa, Jan Kunc, Yike Hu, Galit Levitin, Walt A de Heer, et al.. Local work function measurements of plasma-fluorinated epitaxial graphene. Applied Physics Letters, 2014, 104 (8), pp.081607. ⟨10.1063/1.4866783⟩. ⟨hal-01002911⟩