A technical paper titled “Exciton-assisted electron tunnelling in van der Waals heterostructures” was published by researchers at ETH Zürich, The Barcelona Institute of Science and Technology, Swiss Federal Laboratories for Materials Science and Technology, National Institute for Materials Science, University of Basel, and Institució Catalana de Recerca i Estudis Avançats (ICREA).
“The control of elastic and inelastic electron tunnelling relies on materials with well-defined interfaces. Two-dimensional van der Waals materials are an excellent platform for such studies. Signatures of acoustic phonons and defect states have been observed in current-to-voltage measurements. These features can be explained by direct electron-phonon or electron-defect interactions. Here we use a tunnelling process that involves excitons in transition metal dichalcogenides (TMDs). We study tunnel junctions consisting of graphene and gold electrodes separated by hexagonal boron nitride with an adjacent TMD monolayer and observe prominent resonant features in current-to-voltage measurements appearing at bias voltages that correspond to TMD exciton energies. By placing the TMD outside of the tunnelling pathway, we demonstrate that this tunnelling process does not require any charge injection into the TMD. The appearance of such optical modes in electrical transport introduces additional functionality towards van der Waals material–based optoelectronic devices.”
Find the technical paper here. Published: June 2023. Read this related news article from ETH Zürich.
Wang, L., Papadopoulos, S., Iyikanat, F. et al. Exciton-assisted electron tunnelling in van der Waals heterostructures. Nat. Mater. (2023). https://doi.org/10.1038/s41563-023-01556-7
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