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Two-dimensional transition metal dichalcogenides (TMDs) are the most prominent group of optically active van-der-Waals materials and show promising properties such as the potential for high carrier mobility, atomic thickness, and ultrafast charge transfer. The implications of fast charge and energy transfer for optoelectronic, energy-, and light-harvesting applications has made this group of materials one of the most well-studied ones over the past years. However, previous work employed techniques not uniquely suited to study the processes in these materials, especially with respect to the temporal resolution, yielding only insufficient information about the physics of the system.

In this talk, I will give an overview about the technique called multi-dimensional coherent spectroscopy (MDCS) that we employ to study the charge and energy transfer in a MoSe2/WSe2 heterostructure. Using this technique, we are able to infer information about the dominance of charge transfer on a sub-picosecond time-scale in these samples, the underlying time-scales of other processes occurring in the material such as fast decay into dark states, and the high spatial inhomogeneity of these dynamics. We are also able to clearly distinguish between energy and charge transfer dynamics. I will explain how our implementation of MDCS can be combined with existing imaging techniques and how we plan to use this in the future to advance the study of these promising materials for electronic applications.