1. European Organization for Nuclear Research (CERN), CH-1211 Geneva, Switzerland
2. Institute for Materials Science and Center for Nanointegration, Duisburg-Essen (CENIDE), University of Duisburg-Essen, 45141 Essen, Germany
3. Department of Materials for Electronics, Technical University of Ilmenau, Gustav-Kirchhoff-Straße 5, 98693 Ilmenau, Germany