Dresden 2011 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 44: Poster Session I

HL 44.73: Poster

Dienstag, 15. März 2011, 18:00–21:00, P3

Optical spectroscopy study of c(4x2) Ge (001)-surfaces, covered with atomic Au wires — Utz Bass¹, Eugen Speiser², Sebastian Meyer¹, Jörg Schäfer¹, Norbert Esser², and •Jean Geurts¹ — ¹Universität Würzburg, Physikalisches Institut, Am Hubland, 97074 Würzburg — ²ISAS, Albert-Einstein-Straße 9, 12489 Berlin

Novel quasi-1D systems like e.g. atomic gold chains on a c(4x2) reconstructed Ge(001)-surfaces enable the investigation of 1D-effects like the possible occurrence of the Luttinger- to Fermi liquid transition. As there is a crucial interplay of the lattice vibrations and the electrical and structural properties on such sensitive systems, phonon dynamics are in the focus of this work. The phonons were addressed by Raman spectroscopy and reveal a clear change from the Ge-oxide layer to the final surface with Au-nano wires. Thermally deoxidizing the Ge-surface under UHV leads to a distinct low-frequency vibration around 65cm-1. Its frequency range and its persistence after Gold deposition in the submonolayer range indicate that this signal is surface related. Additionally, the surface-induced anisotropy of the optical reflectance was complementary investigated by Reflectance-Anisotropy-Spectroscopy (RAS) and IR-ellipsometry.