How the Complementarity at Vicinal Steps Enables Growth of 2D Monocrystals
Large 2D monocrystals are highly sought after yet hard to achieve; unlike graphene, most dichalcogenides and h-BN possess low symmetry, which allows for nucleation of mutually inverted pieces, merging into polycrystals replete with grain boundaries. On vicinal substrate surfaces such growing pieces were observed to orient alike, and very recently this effect apparently enabled the growth of large single crystal h-BN. Addressing the compelling questions of how such a growth process can operate and what the key mechanisms are is crucial in guiding the substrate selection for optimal synthesis of perhaps many materials. To this end, the basic crystallography and atomistic-modeling theory presented here reveal (i) how the undulations of the ever-wandering steps do not, surprisingly, disturb the orientations of the attached 2D-nuclei, whose direction remains robust owing to complementarity between the meandering step and h-BN counterpart if their kinks have similar size of negligible misfit, δk < 0.1 Å. (ii) Stronger chemical affinity of metal to the N atoms at the zigzag edge of h-BN singles out its particular orientation, without evidence of any epitaxy, at the edge or to the surface. (iii) The monocrystal integrity requires unhindered growth spillover across the steps and the seamless healing of the residual fissures, caused by the very same steps necessary for co-orientation. Molecular dynamics simulations show this happening for the steps not taller than the BN bond, s < 1.44 Å. Furthermore, these criteria point to [–1 1 2] steps on the Cu (110) surface, in accord with experimental results, while other possibilities can also be predicted.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); National Science Foundation (NSF)
- Grant/Contract Number:
- SC0012547; AC02-05CH11231; OCI-0959097
- OSTI ID:
- 1530801
- Journal Information:
- Nano Letters, Vol. 19, Issue 3; ISSN 1530-6984
- Publisher:
- American Chemical SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Epitaxial growth of a 100-square-centimetre single-crystal hexagonal boron nitride monolayer on copper
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journal | May 2019 |
Proton conductivity of a hexagonal boron nitride membrane and its energy applications
|
journal | January 2020 |
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