Interfaces determine the functional properties of many materials in a decisive way. For instance, transport along and across interfaces is of key importance for energy conversion and storage. Control of interfacial phenomena is a major focus of research in the IMPRS-CMS. The synthesis of high-quality semiconductor devices in state-of-the-art cleanroom facilities has enabled major recent progress in research on quantum phenomena in dilute electron systems, including the quantum Hall effects, excitonic Bose condensation, and microwave-induced zero-resistance states. In recent years, atomic layer deposition techniques have also been applied with increasing success to more complex materials such as transition metal oxides and organic solids, permitting the creation of dense correlated-electron systems with controlled dimensionality, electronic structure, and phase behavior as well as field-effect devices with novel functionalities. IMPRS-CMS students will thus be exposed to preparation, structuring, and interface-specific characterization techniques across several different materials platforms.