High-Frequency Elastic Coupling at the Interface of van der Waals Nanolayers Imaged by Picosecond Ultrasonics

Greener, Jake D.G.; de Lima Savi, Elton; Akimov, Andrey V.; Raetz, Samuel; Kudrynskyi, Zakhar; Kovalyuk, Zakhar D.; Chigarev, Nikolay; Kent, Anthony; Patan�, Amalia; Gusev, Vitalyi E.

Abstract

Although the topography of van de Waals (vdW) layers and heterostructures can be imaged by scanning probe microscopy, high-frequency interface elastic properties are more difficult to assess. These can influence the stability, reliability and performance of electronic devices that require uniform layers and interfaces. Here, we use picosecond ultrasonics to image these properties in vdW layers and heterostructures based on well-known exfoliable materials, i.e. InSe, hBN and graphene. We reveal a strong, uniform elastic coupling between vdW layers over a wide range of frequencies of up to tens of gigahertz (GHz) and in-plane areas of 100 _m2. In contrast, the vdW layers can be weakly coupled to their supporting substrate, behaving effectively as free standing membranes. Our data and analysis demonstrate that picosecond ultrasonics offers opportunities can probe the high-frequency elastic coupling of vdW nanolayers and image both perfect and broken interfaces between different materials over a wide frequency range, as required for future scientific and technological developments.

Citation

Greener, J. D., de Lima Savi, E., Akimov, A. V., Raetz, S., Kudrynskyi, Z., Kovalyuk, Z. D., Chigarev, N., Kent, A., Patané, A., & Gusev, V. E. (2019). High-Frequency Elastic Coupling at the Interface of van der Waals Nanolayers Imaged by Picosecond Ultrasonics. ACS Nano, 13(10), 11530-11537. https://doi.org/10.1021/acsnano.9b05052

• Journal Article Type: Article
• Acceptance Date: Sep 5, 2019
• Online Publication Date: Sep 5, 2019
• Publication Date: Oct 22, 2019
• Deposit Date: Sep 12, 2019
• Publicly Available Date: Sep 6, 2020
• Journal: ACS Nano
• Print ISSN: 1936-0851
• Electronic ISSN: 1936-086X
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 13
• Issue: 10
• Pages: 11530-11537
• DOI: https://doi.org/10.1021/acsnano.9b05052
• Keywords: General Engineering; General Physics and Astronomy; General Materials Science
• Public URL: https://nottingham-repository.worktribe.com/output/2608443
• Publisher URL: https://pubs.acs.org/doi/abs/10.1021/acsnano.9b05052
• Additional Information: This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in ACS Nano, copyright ©American Chemical Society after peer review. To access the final edited and published work see https://pubs.acs.org/doi/abs/10.1021/acsnano.9b05052
• Contract Date: Sep 12, 2019