The Paul-Drude-Institut für Festkörperelektronik (PDI) plays a pathfinding role in pushing the outermost frontiers of materials and nanoscale devices for solid-state electronics and photonics. This exploratory work is firmly grounded on PDI’s expertise in molecular beam epitaxy, a materials growth technique with extraordinary control and precision on the atomic scale. In a lively symbiosis between materials science and solid-state physics, PDI investigates the fundamentals of epitaxial growth, novel inorganic materials and nanoscale heterostructures, at the same time exploring the quantum physics of such structures with regard to innovative device concepts.