Two-dimensional Materials

The properties of two-dimensional materials differ in many aspects from their bulk counterparts. Therefore, 2D materials are envisaged to play an important role in future electronic devices. The unique electronic properties may however be easily affected by e.g. ambient conditions due to the two-dimensional nature of the corresponding material. We fabricate samples of 2D materials, such as graphene and single layer TMDCs and Janus materials, investigate their intrinsic properties, 2D heterostructures and study how these can be modified in a controlled way.

Our research is funded by various funding agencies, such as DFG, BMBF, DAAD, AvH-Stiftung, and the EU.

Ion-Solid Interaction

We study the energy transport and dissipation processes on the nanoscale in 2D materials (metals, dielectrics and heterosystems) after strong localized electronic excitations induced by energetic ions. The details of the relevant physical mechanisms depend strongly on the type of ion, its kinetic energy and charge state.

We aim to gain a better understanding of ion-surface interactions using various ion beams provided by accelerator facilities such as GANIL, GSI, RBI and by our own Beamline HICS. The results will help to reveal the fundmental mechanisms of ion-solid interactions and to establish methods for the controlled modification of surfaces and 2D materials by energetic ion irradiation.

Ion sources

To obtain a quantitative characterisation of energy dissipation processes in solids during and after the impact of energetic ions we use special kinds of ion types and sources, respectively:

Swift heavy ions (SHI). This type of beam is generated in large scale accelerators, such as GSI or GANIL. The projectiles trigger an intense electronic excitation along their trajectory, which may result in permanent modifications, the so-called ion tracks. In a grazing incidence geometry these tracks can be studied at the surface of a material.

Highly charged ions (HCI). These projectiles offer the unique possibility to study both, the effects of kinetic and potential energy on energy dissipation during the ion-solid interaction. The HCI are produced by an Electron Beam Ion Source (EBIS) at our HICS-setup. 

In addition, we are currently developing a new sub-ps ion source which will for the first time enable pump-probe-type experiments and thus give direct experimental acces to the non-equilibrium state (see SFB 1242).