Self-organized twist-heterostructures via aligned van der Waals epitaxy and solid-state transformations

Authors

Peter Sutter, University of Nebraska-LincolnFollow
Rina Ibragimova, Aalto University
Hannu-Pekka Kosma, Aalto University
Bruce A. Parkinson, University of Wyoming
Eli A. Sutter, University of Nebraska–LincolnFollow

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

Document Type

Article

Date of this Version

2019

Citation

The Author(s) 2019

Comments

NATURE COMMUNICATIONS | (2019)10:5528 | https://doi.org/10.1038/s41467-019-13488-5 | www.nature.com/naturecommunications

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.