Berlin 2018 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 29: Metallic nanowires on semiconductor surfaces

O 29.2: Vortrag

Dienstag, 13. März 2018, 10:45–11:00, MA 144

Infrared Spectroscopic Investigations of Charge Transfer in Quasi-1D Au-Induced Superstructures on Vicinal Silicon Surfaces — •Michael Tzschoppe, Christian Huck, Fabian Hötzel, and Annemarie Pucci — Kirchhoff Institute for Physics, Heidelberg University, Germany

Thermal evaporation of Au on vicinal silicon (e.g. Si(553)) under ultrahigh vacuum (UHV) conditions leads to atomic chain growth preferably along the step edges. During the experiments, the quality of the silicon surface, as well as the defined preparation of the atomic chains, are proven by reflective high energy electron diffraction (RHEED) measurements. We studied the plasmonic excitations of the metallic quasi-one-dimensional chains in the mid-infrared spectral region by Fourier transform infrared (FTIR) spectroscopy. By applying a model for excitations at low energies,^[1] we are able to describe the spectrum and therefore to extract the one-dimensional free charge carrier concentration. In this talk, we will present how the free charge carrier concentration can be modified by doping the superstructures with organic molecules. For doping with C₇₀, the molecular adsorption leads to an increase of the plasmonic signal which can be attributed to an uptake of electrons by the C₇₀ molecules adsorbed on the surface.

Hötzel et al. Nano Lett. 15, 4155-4160 (2015)