Step-Flow Growth of Graphene-Boron Nitride Lateral Heterostructures by Molecular Beam Epitaxy

Thomas, James; Bradford, Jonathan; Cheng, Tin S.; Summerfield, Alex; Wrigley, James; Mellor, Chris J.; Khlobystov, Andrei; Foxon, Charles Thomas; Eaves, Laurence; Novikov, Sergei V.; Beton, Peter H.

Abstract

Integration of graphene and hexagonal boron nitride (hBN) into lateral heterostructures has drawn focus due to the ability to broadly engineer the material properties. Hybrid monolayers with tuneable bandgaps have been reported, while the interface itself possesses unique electronic and magnetic qualities. Herein, we demonstrate lateral heteroepitaxial growth of graphene and hBN by sequential growth using high-temperature molecular beam epitaxy (MBE) on highly ordered pyrolytic graphite (HOPG). We find, using scanning probe microscopy, that graphene growth nucleates at hBN step edges and grows across the surface to form nanoribbons with a controlled width that is highly uniform across the surface. The graphene nanoribbons grow conformally from the armchair edges of hexagonal hBN islands forming multiply connected regions with the growth front alternating from armchair to zigzag in regions nucleated close to the vertices of hexagonal hBN islands. Images with lattice resolution confirm a lateral epitaxial alignment between the hBN and graphene nanoribbons, while the presence of a moiré pattern within the ribbons indicates that some strain relief occurs at the lateral heterojunction. These results demonstrate that high temperature MBE is a viable route towards integrating graphene and hBN in lateral heterostructures.

Citation

Thomas, J., Bradford, J., Cheng, T. S., Summerfield, A., Wrigley, J., Mellor, C. J., Khlobystov, A., Foxon, C. T., Eaves, L., Novikov, S. V., & Beton, P. H. (2020). Step-Flow Growth of Graphene-Boron Nitride Lateral Heterostructures by Molecular Beam Epitaxy. 2D Materials, 7(3), Article 035014. https://doi.org/10.1088/2053-1583/ab89e7

• Journal Article Type: Article
• Acceptance Date: Apr 7, 2020
• Online Publication Date: Apr 16, 2020
• Publication Date: 2020-07
• Deposit Date: Apr 20, 2020
• Publicly Available Date: Apr 17, 2021
• Journal: 2D Materials
• Electronic ISSN: 2053-1583
• Publisher: IOP Publishing
• Peer Reviewed: Peer Reviewed
• Volume: 7
• Issue: 3
• Article Number: 035014
• DOI: https://doi.org/10.1088/2053-1583/ab89e7
• Public URL: https://nottingham-repository.worktribe.com/output/4309538
• Publisher URL: https://iopscience.iop.org/article/10.1088/2053-1583/ab89e7
• Additional Information: This is the Accepted Manuscript version of an article accepted for publication in 2D Materials. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://iopscience.iop.org/article/10.1088/2053-1583/ab89e7