Wednesday 03/05/2023, 12:00
FORTH Seminar Room 1
Dr. Laurent Lombez LPCNO, INSA Toulouse, CNRS, Toulouse, France
e-mail: [email protected]
Following the graphene craze, the scientific community is currently interested in the properties of new 2D materials that exhibit extraordinary optical and electrical properties: the family of Transition Metal Dichalcogenides (TMDs). These materials are semiconductors with a tunable bandgap that ranges from the visible to the near-infrared spectrum. It is crucial to measure the charge and spin transport properties of these materials and develop ultrathin optoelectronic and/or spintronic devices based on TMDs. In this talk, I will focus on the transport properties of WSe2 monolayers using optical spectroscopy. WSe2 is known to host a wide range of excitons, which are strongly bound electron-hole pairs. I will first analyze the transport properties of excitons when coupled to an electron reservoir (trionic species) and then demonstrate how it is possible to strongly spin/valley polarize the electron sea. The transport of this polarization can be carried out on a much larger scale than the classical exciton diffusion lengths, reaching up to tens of microns. Finally, I will show novel results of unidirectional excitonic transport on a coplanar WSe2/MoSe2 structure.