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Accueil > Séminaires > Année 2019 > Séminaire de Stéphane Berciaud (21 mai 2019)

Séminaire de Stéphane Berciaud (21 mai 2019)

Institut de Physique et Chimie des Matériaux de Strasbourg UMR 7504, Université de Strasbourg and CNRS

par Martrenchard-Barra Séverine - 26 avril

Probing interlayer coupling and valley contrasting properties in atomically-thin transition metal dichalcogenide-graphene heterostructures

Two-dimensional materials, such as transition metal dichalcogenides (TMD), graphene or boron nitride compose a unique toolkit of atomically-thin crystals with remarkable electronic, optical, spin and valley properties. These assets can possibly be enhanced by stacking 2D layers into so-called van der Waals heterostructures and thereby tailoring novel opto-electronic functionalities and devices. The performance of such devices is governed by near-field coupling through, e.g., interlayer charge and/or energy transfer. As a result, new concepts and experimental methodologies are needed to properly describe atomically sharp heterointerfaces in van der Waals heterostructures. During this seminar, I will introduce an original study of interlayer charge and energy transfer in a model 2D semiconductor-metal heterojunction [i.e., transition metal dichalcogenide (TMD)-graphene]. Using a combination of micro-photoluminescence (PL) and Raman scattering spectroscopies at variable temperature, we are able to disentangle contributions from slow photoinduced charge transfer phenomena and much faster (picosecond) energy transfer. As an outlook, I will discuss the implications of our results for opto-valleytronic applications in light of our recent studies of valley polarization and coherence in TMD-graphene heterostructures.

This work was done with E. Lorchat, Luis Parra-Lopez and G. Froehlicher at IPCMS ; C. Robert, D. Lagarde, X. Marie at LPCNO (INSA Toulouse) ; S. Azzini, T. Chervy, T.W. Ebbesen and C. Genet at ISIS (Strasbourg).

Séminaire de Stéphane Berciaud - 152.1 ko

21 mai 2014