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Accueil > Séminaires > Année 2023 > Séminaire de Sotirios Papadopoulos (14 nov)

Séminaire de Sotirios Papadopoulos (14 nov)

ETH Zurich

par Martrenchard-Barra Séverine - 26 octobre 2023 (modifié le 2 novembre 2023)

Exciton-assisted tunneling in van der Waals heterostructures

Transition metal dichalcogenides (TMDs) are semiconductors that have attracted attention due to their interesting electronic and optical properties. By combining TMDs with conductors (i.e. graphene) and insulators (i.e. hexagonal boron nitride - hBN) we can fabricate electrically-controlled light-emitting tunnel junctions. In this talk, I will discuss the various inelastic tunneling processes present in van der Waals tunnel junctions with a focus on our recent results on exciton-assisted tunneling [1,2]. Excitonic emission is observed in tunnel junctions in which the TMD is positioned outside of the tunneling pathway. In addition, prominent resonant features appear in electrical measurements. I will talk about how we interpret these effects as energy transfer from tunneling electrons to excitons and what is its contribution to light generation in such devices. Finally, I will discuss the prospects of applying the acquired understanding not only to design efficient light sources and photodetectors but also to demonstrate all electrical on-chip spectroscopy of two-dimensional materials.

[1] Sotirios Papadopoulos*, Lujun Wang*, Takashi Taniguchi, Kenji Watanabe, Lukas Novotny, Energy transfer from tunneling electrons to excitons, arXiv:2209.11641 (2022)

[2] Lujun Wang*, Sotirios Papadopoulos*, Fadil Iyikanat*, Jian Zhang, Jing Huang, Kenji Watanabe, Takashi Taniguchi, Michel Calame, Mickael L Perrin, F. Javier García de Abajo, Lukas Novotny, Exciton-assisted electron tunneling in van der Waals heterostructures, Nat. Mater. 22, 1094–1099 (2023). https://doi.org/10.1038/s41563-023-01556-7

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