Regensburg 2010 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 41: Poster Session I (Semiconductor Substrates: Epitaxy and growth; Semiconductor Substrates: Adsorbtion; Semiconductor Substrates: Solid-liquid interfaces; Semiconductor Substrates: Clean surfaces; Oxides and insulators: Epitaxy and growth; Oxides and insulators: Adsorption; Oxides and insulators: Clean surfaces; Organic, polymeric and biomolecular films - also with adsorbates; Organic electronics and photovoltaics, Surface chemical reactions; Heterogeneous catalysis; Phase transitions; Particles and clusters; Surface dynamics; Surface or interface magnetism; Electron and spin dynamics; Spin-Orbit Interaction at Surfaces; Electronic structure; Nanotribology; Solid/liquid interfaces; Graphene; Others)
O 41.17: Poster
Dienstag, 23. März 2010, 18:30–21:00, Poster B1
Charge Switching of Donor Ensembles in a Semiconductor — •Karen Teichmann1, Martin Wenderoth1, Sebastian Loth1, Rainer G. Ulbrich1, Jens K. Garleff2, A. P. Wijnheijmer2, and Paul M. Koenraad2 — 1IV. Physikalisches Institut, Georg-August Universität Göttingen, Germany — 2PSN, Eindhoven University of Technology, the Netherlands
We investigated the charge state switching behaviour of interacting donors near the GaAs (110) surface, by Scanning Tunnelling Microscopy (STM). Silicon doped (n ≈ 6 · 1018 cm−3) GaAs is cleaved in UHV to obtain a clean and atomically flat surface, directly afterwards the sample is transferred into a home build STM, working at 5 Kelvin. Using the STM tip as a movable gate the charge state of each donor can be switched from the neutral to the ionized state [1]. The charge configuration of a single isolated donor is unambiguously determined by the position of the tip and the applied voltage. In contrast, even a two donor system with inter donor distances smaller than 5 nm shows a more complex behavior. The electrostatic interaction of two donors close together can result in ionization gaps. In certain geometrical configurations the modified electronic properties of donors close to the surface [2] can result in bistable and time dependent charge switching behavior. We acknowledge financial support by the DFG SPP 1285.
[1] PRL 101, 076103 (2008)
[2] PRL 102, 166101 (2009)