X-ray diffractometer for MBE-grown epitaxial thin films

• Subject Area: Condensed Matter Physics
• Term: Funded in 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 544410649

We propose to install an X-ray diffractometer which is optimized for the characterizations of epitaxial thin films grown by the molecular beam epitaxy (MBE) method. The characterizations include the θ-2θ analysis of the Bragg diffraction pattern to confirm the epitaxial growth and to identify the crystallographic structure as well as the measurements of the Kiessig fringes to estimate the thicknesses of the layers in epitaxial heterostructures. The instrument will be primarily (90% of the machine time) used in the work group of Prof. Ando (Physics Institute II of the University of Cologne), which is one of the world-leading groups in the MBE-growth of topological insulator thin films. Since the group owns four MBE machines and regularly grows a lot of thin films, there is a very high demand of an X-ray diffractometer to characterize the grown films on a daily basis. Right now the work group is relying on a 14-year-old Japanese machine which was brought from Osaka University upon the appointment of Prof. Ando at the University of Cologne, but in recent years this machine frequently breaks down due to various problems because it is getting too old. The down time and the repair costs are heavily hurting the research activities of the work group. The thin films grown in the Ando Group play important roles not only in the device research performed in the own group, but also in the collaborations performed in the frameworks of the DFG-funded large-scale projects, Collaborative Research Center 1238 and the Cluster of Excellence ML4Q.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Röntgendiffraktometer für MBE-gewachsene kristalline dünne Schichten
• Instrumentation Group: 4011 Pulverdiffraktometer
• Applicant Institution: Universität zu Köln
• Leader: Professor Dr. Yoichi Ando