Berlin 2018 – scientific programme

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O: Fachverband Oberflächenphysik

O 26: Organic-inorganic hybrid systems and organic films III

O 26.6: Talk

Tuesday, March 13, 2018, 11:45–12:00, MA 042

How Doping Influences the Nature of Charge Transfer at ZnO/F4TCNQ Interfaces — •Simon Erker and Oliver T. Hofmann — Institute of Solid State Physics, NAWI Graz, Graz University of Technology, Austria

At inorganic/organic interfaces, charge transfer occurs in different forms depending on the nature of the substrate. On metals, where the adsorbate often hybridizes with the substrate, hybrid bands a formed. These lead to a uniform, fractional charging of the organic monolayer. In contrast, on insulating and inert substrates, charge is transferred as integer electrons, which leads to the coexistence of charged and neutral molecules on the surface. In this contribution, we study the charge distribution of F4TCNQ on ZnO using hybrid density functional theory. ZnO is particular interesting substrate, which allows to study the transition between these two mechanisms. Experimentally, it can be produced with high purity or doped until metallic conductance. Moreover, while the 000-1 surface is inert due to the presence of a hydrogen overlayer, the 10-10 surface exposes surface Zn atoms that can hybridize with organic adsorbates. Employing a recently developed approach to incorporate doping and the effect of long-ranged band bending into our calculations, we investigate the transition between fractional and integer charging as function of the doping concentration for the two different surfaces.