In situ chemical and structural investigations of the oxidation of Ge(001) substrates by atomic oxygen

The exposure of Ge001 substrates to atomic oxygen was studied in situ to establish the stability of the germanium oxide. After preparing chemically clean and atomically flat Ge001 surfaces, the Ge samples were exposed to atomic oxygen in a wide temperature range from room temperature to 400 °C. The chemical composition of the so-formed oxides was studied by means of x-ray photoelectron spectroscopy, while the structure was observed by reflection high energy electron diffraction. At low substrate temperatures the atomic oxygen is efficiently chemisorbed and suboxides coexist with the dioxide, which in turn is remarkably promoted in the high temperature range.