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Introducing Overlapping Grain Boundaries in Chemical Vapor Deposited Hexagonal Boron Nitride Monolayer Films

Authors/others:Bayer, Bernhard C,Caneva, Sabina (University of Cambridge) Pennycook, Timothy J.Kotakoski, JaniMangler, ClemensHofmann, Stephan (University of Cambridge) Meyer, Jannik C.
Abstract:We demonstrate the growth of overlapping grain boundaries in continuous, polycrystalline hexagonal boron nitride (h-BN) monolayer films via scalable catalytic chemical vapor deposition. Unlike the commonly reported atomically stitched grain boundaries, these overlapping grain boundaries do not consist of defect lines within the monolayer films but are composed of self-sealing bilayer regions of limited width. We characterize this overlapping hBN grain boundary structure in detail by complementary (scanning) transmission electron microscopy techniques and propose a catalytic growth mechanism linked to the subsurface/bulk of the process catalyst and its boron and nitrogen solubilities. Our data suggest that the overlapping grain boundaries are comparatively resilient against deleterious pinhole formation associated with grain boundary defect lines and thus may reduce detrimental breakdown effects when polycrystalline h-BN monolayer films are used as ultrathin dielectrics, barrier layers, or separation membranes.
Number of pages:7
Date of publication:5.2017
Journal title:ACS Nano
Digital Object Identifier (DOI):http://dx.doi.org/10.1021/acsnano.6b08315
Publication Type:Article
Research Group Physics of Nanostructured Materials
Faculty of Physics

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