Moiré-modulated conductance of hexagonal boron nitride tunnel barriers

Summerfield, Alex; Kozikov, Aleksey; Cheng, Tin S.; Davies, Andrew; Cho, Yong-Jin; Khlobystov, Andrei N.; Mellor, Christopher J.; Foxon, C. Thomas; Watanabe, Kenji; Taniguchi, Takashi; Eaves, Laurence; Novoselov, Kostya S.; Novikov, Sergei V.; Beton, Peter H.

Abstract

Monolayer hexagonal boron nitride (hBN) tunnel barriers investigated using conductive atomic force microscopy reveal moiré patterns in the spatial maps of their tunnel conductance consistent with the formation of a moiré superlattice between the hBN and an underlying highly ordered pyrolytic graphite (HOPG) substrate. This variation is attributed to a periodc modulation of the local density of states and occurs for both exfoliated hBN barriers and epitaxially grown layers. The epitaxial barriers also exhibit enhanced conductance at localized subnanometer regions which are attributed to exposure of the substrate to a nitrogen plasma source during the high temperature growth process. Our results show clearly a spatial periodicity of tunnel current due to the formation of a moiré superlattice and we argue that this can provide a mechanism for elastic scattering of charge carriers for similar interfaces embedded in graphene/hBN resonant tunnel diodes.

Citation

Summerfield, A., Kozikov, A., Cheng, T. S., Davies, A., Cho, Y., Khlobystov, A. N., …Beton, P. H. (in press). Moiré-modulated conductance of hexagonal boron nitride tunnel barriers. Nano Letters, https://doi.org/10.1021/acs.nanolett.8b01223

• Journal Article Type: Article
• Acceptance Date: Jun 13, 2018
• Online Publication Date: Jun 18, 2018
• Deposit Date: Jul 10, 2018
• Publicly Available Date: Jun 19, 2019
• Journal: Nano Letters
• Print ISSN: 1530-6984
• Electronic ISSN: 1530-6984
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• DOI: https://doi.org/10.1021/acs.nanolett.8b01223
• Keywords: boron nitride ; epitaxy ; growth ; tunnelling ; superlattice; ; moiré ; heterostructure
• Public URL: https://nottingham-repository.worktribe.com/output/939654
• Publisher URL: https://pubs.acs.org/doi/10.1021/acs.nanolett.8b01223
• Additional Information: This document is the Accepted Manuscript version of a Published Work that appeared in final form in ; Nano Letters, copyright © American Chemical Society 2018 after peer review and technical editing by t he publisher. ; To access the final edited and published work see https://pubs.acs.org/doi/10.1021/acs.nanolett.8b01223