Interaction of ion beams with solid surfaces

The Ion Beam Center, operated by the Institute of Ion Beam Physics and Materials Research (IIM), has a long tradition of studying the interaction of ions with solids. Without a fundamental understanding of the deceleration of ions and the resulting change in the irradiated materials, ion beam-based methods cannot be developed efficiently. In particular, when using highly charged and low-energy ions, the processes of energy deposition and relaxation are not yet fully understood because they occur in non-equilibrium directly at the surface. Such processes can be investigated by studying the transmission of highly charged ions through ultrathin films, such as 2D materials, and by studying surface modifications after single ion bombardment and continuous erosion. In combination and with the aid of atomistic simulations, these observations can extend the understanding of ion interaction in this region and thus predict the best conditions for doping or defect generation of 2D materials or for surface modifications.

In contrast to large-area irradiation, focused ion beams offer the possibility of targeted local modification and defect generation up to deterministic single ion implantation. Liquid metal ion sources can be used to provide a broad spectrum of doping atoms, while in the ion microscope He and Ne ion beams with 1-3 nm diameters can be used for local modification. The interaction of focused beams with nanostructures is also not yet understood in detail, since boundary conditions come into play that can lead to complex behavior, e.g., inhomogeneous doping or shape change. Simulations of the collision cascade in 3D can help to interpret the experimental observations.

Participating departments of the institute