Dresden 2017 – scientific programme
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DS: Fachverband Dünne Schichten
DS 3: Thin Film Characterisation: Structure Analysis and Composition I
DS 3.2: Talk
Monday, March 20, 2017, 09:45–10:00, CHE 91
XPD experiments and simulation of GaAs(001)-c(8x2) — •Karim Shamout1,2, Philipp Espeter1,2, Peter Roese1,2, Ulf Berges1,2, and Carsten Westphal1,2 — 1Experimentelle Physik I - Technische Universität Dortmund, Otto-Hahn-Str. 4a, D-44221 Dortmund — 2DELTA - Technische Universität Dortmund, Maria-Goeppert-Mayer-Str. 2, D-44221 Dortmund
The III-V compound semiconductor gallium arsenide is an applicable substrate for spin-tronic multilayer systems due to its electronical and magnetic properties. GaAs(001) is found in various reconstructions determined by the Ga-As ratio in the top atom surface layer. In this work, we analyse of the GaAs surface reconstructions, and here especially the GaAs(001)-c(8x2) structure where huge uncertainties arise. Photoelectron diffraction (XPD) provides detailed information of the surface and interface of the sample. Thereby Ga or As dimers located 5 Å beneath the surface can be resolved. In literature, 8 different possible structures of the GaAs-c(8x2) surface have been shown. These structures differ by the number of Ga dimers, the sub-dimers or the arrangement of Ga-As rings. Here we present the experimental data of the GaAs-c(8x2) surface measured with XPD at the U55 beamline 11 at DELTA. For each possible structure an XPD pattern has been simulated and compared to the experimental data. As a result, the structure suggested by Kumpf et al. fits best to the data. Further, the precise location of the Ga-dimers is found. Moreover, we analyse the interface of Co/GaAs(001)-c(8x2) and investigate on the stability of the GaAs reconstruction beneath Co.