Laboratory for surface femtophysics

Growing 2D materials, e.g. graphene and Transition Metal Dichalcogenides (TMD) monolayers, is recently used to produce novel electronic, photonic and valleytronic devices. These include high mobility GHz field-effect transistors with large on/off ratios or fast response phototransistors, which can be used as infrared detectors or extremely sensitive chemical sensors.

TMD monolayers also hold a significant potential for making ultrathin flexible photovoltaic (PV) cells with 1-3 orders of magnitude higher power densities than the best existing thin-film solar cells. In such materials, optoelectronic and photovoltaic response is governed by the light-induced dynamics of excitons and creation of free charges upon photoexcitation. Therefore, the knowledge of the excitonic response to the optical stimuli is a crucial for optoelectronic and photovoltaic applications.

With time-resolved ARPES (tr-ARPES) we will investigate such dynamics and characteristic relaxation processes on ultrashort timescales and with energy and momentum resolution. For this purpose, tr-ARPES based on XUV source, will be built.