Dresden 2009 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 27: Poster Session I (Methods: Scanning probe techniques; Methods: Atomic and electronic structure; Methods: Molecular simulations and statistical mechanics; Oxides and Insulators: Clean surfaces; Oxides and Insulators: Adsorption; Oxides and Insulators: Epitaxy and growth; Semiconductor substrates: Clean surfaces; Semiconductor substrates: Epitaxy and growth; Semiconductor substrates: Adsorption; Nano- optics of metallic and semiconducting nanostructures; Electronic structure; Methods: Electronic structure theory; Methods: other (experimental); Methods: other (theory); Solutions on surfaces; Epitaxial Graphene; Surface oder interface magnetism; Phase transitions; Time-resolved spectroscopies)

O 27.59: Poster

Dienstag, 24. März 2009, 18:30–21:00, P2

FTIR-Spectroscopy of MOCVD-Prepared Silicon (100) — •Peter Kleinschmidt, Anja Dobrich, Henning Döscher, Sebastian Brückner, Christian Höhn, and Thomas Hannappel — Helmholtz-Zentrum Berlin für Materialien und Energie, Glienicker Str. 100, 14109 Berlin

Using silicon to replace III-V semiconductors or germanium as a substrate material in high-performance devices like high-efficiency multi-junction solar cells is attractive due to cost considerations and better availability. In order to achieve defect-free epitaxy on Si(100), the surface should exhibit double atomic steps. MOCVD-preparation of Si(100) typically results in single atomic steps where Si-Si dimer orientation alternates on adjacent terraces. In the MOCVD reactor, the presence of hydrogen may have a crucial impact on the step formation at the surface.

We have investigated MOCVD-prepared Si(100) using Fourier-transform infrared (FTIR) spectroscopy in an attenuated total reflection (ATR) configuration enabling sensitive measurements of the silicon-hydrogen bonds at the surface. The measurements showed Si-H mono-hydrides, which are characterized by absorption lines due to a symmetric and an antisymmetric stretch mode. This is in agreement with results from low-energy electron diffraction (LEED) and scanning tunneling microscopy (STM), which indicated that the surface unit cell consists of silicon dimers. The FTIR measurements suggest that the dangling bonds of the dimers are saturated with hydrogen.