Electrical & Computer Engineering, Department of
ORCID IDs
http://orcid.org/0000-0002-3301-309X
http://orcid.org/0000-0001-5773-3457
http://orcid.org/0000-0002-0970-0957
http://orcid.org/0000-0002-6939-2714
Date of this Version
2019
Citation
The Author(s) 2019
Abstract
Vertical van der Waals (vdW) heterostructures of 2D crystals with defined interlayer twist are of interest for band-structure engineering via twist moiré superlattice potentials. To date, twist-heterostructures have been realized by micromechanical stacking. Direct synthesis is hindered by the tendency toward equilibrium stacking without interlayer twist. Here, we demonstrate that growing a 2D crystal with fixed azimuthal alignment to the substrate followed by transformation of this intermediate enables a potentially scalable synthesis of twisted heterostructures. Microscopy during growth of ultrathin orthorhombic SnS on trigonal SnS2 shows that vdW epitaxy yields azimuthal order even for non-isotypic 2D crystals. Excess sulfur drives a spontaneous transformation of the few-layer SnS to SnS2, whose orientation – rotated 30° against the underlying SnS2 crystal – is defined by the SnS intermediate rather than the substrate. Preferential nucleation of additional SnS on such twisted domains repeats the process, promising the realization of complex twisted stacks by bottom-up synthesis.
Comments
NATURE COMMUNICATIONS | (2019)10:5528 | https://doi.org/10.1038/s41467-019-13488-5 | www.nature.com/naturecommunications