Tuning the properties and functionality of 2D-materials: From substitutional doping to Janus-MoSSe

So-called van-der-Waals materials have revolutionized solid-state physics. Due to the very weak interlayer interaction, they made it possible for the first time to prepare monoatomic single-crystalline layers via mechanical exfoliation. Since then, the number of these two-dimensional (2D) materials has tremendously increased. However, their preparation by mechanical exfoliation is not always possible, as it requires a bulk crystal and for some 2D materials, these simply do not exist. This is in particular true for the so-called Janus materials, where the transition metal is embedded between two layers of different chalcogen atoms (see Fig. 1). Janus 2D materials are predicted to have quite unique properties and their incorporation into devices will open up new opportunities. In this work we report on our recent progress in preparation and characterization of these fascinating materials [1].