Unraveling the 3D Atomic Structure of a Suspended Graphene/hBN van der Waals Heterostructure

Authors/others:Argentero, Giacomo; Mittelberger, Andreas; Ahmad Pour Monazam, Mohammad Reza; Cao, Yang (University of Manchester); Pennycook, Timothy J.; Mangler, Clemens; Kramberger, Christian; Kotakoski, Jani; Geim, A. K. (University of Manchester); Meyer, Jannik C.

In this work we demonstrate that a free-standing van der Waals heterostructure, usually regarded as a flat object, can exhibit an intrinsic buckled atomic structure resulting from the interaction between two layers with a small lattice mismatch. We studied a freely suspended membrane of well-aligned graphene on a hexagonal boron nitride (hBN) monolayer by transmission electron microscopy (TEM) and scanning TEM (STEM). We developed a detection method in the STEM that is capable of recording the direction of the scattered electron beam and that is extremely sensitive to the local stacking of atoms. A comparison between experimental data and simulated models shows that the heterostructure effectively bends in the out-of-plane direction, producing an undulated structure having a periodicity that matches the moiré wavelength. We attribute this rippling to the interlayer interaction and also show how this affects the intralayer strain in each layer.

Number of pages:8
Date of publication:8.3.2017
Journal title:Nano Letters: a journal dedicated to nanoscience and nanotechnology
Peer reviewed:true
Digital Object Identifier (DOI):http://dx.doi.org/10.1021/acs.nanolett.6b04360
Publication Type:Article