Atomically-Precise Texturing of Hexagonal Boron Nitride Nanostripes

h-BN grown on a curved Rh crystal forms a continuous atomically-thin carpet revealing a transformation from 2D to 1D electronic band structure. This novel approach to nanopattering through epitaxial growth has practical technological implications. 

Exploiting fine hBN-based nanostructures requires structural quality down to the atomic scale and precise lateral nano-structuration and integration with other two-dimensional materials, which lies beyond current lithographic capabilities. The bottom-up vapor growth is the alternative, which also works for 2D hybrids, although general procedures to control shape, size, and spatial order of surface phases are still lacking.

A team of researchers from Spain (Donostia, Centro de Fisica de Materials) has found a working disruptive approach: imprinting the lateral pattern of an atomically stepped one-dimensional template into a hBN monolayer. The researchers demonstrate -also through core level photoemission, near edge absorption spectroscopy and ARPES measurements performed at the beamline BACH- the bottom-up synthesis of nanostriped hBN heterostructures with atomically sharp interfaces. The idea was to follow the standard chemical vapor deposition growth route, using rhodium (Rh) vicinal surfaces as one-dimensional (1D) templates. In practice, hBN was epitaxially grown on Rh surfaces using an Rh curved crystal for a systematic exploration, which produces a periodically textured, nanostriped hBN carpet that coats Rh(111)-oriented terraces and lattice-matched Rh(337) facets with tunable width.
Thus, a 1D lateral hBN (111)/(337) heterostructure arises, featuring defect-free boundaries and significant band offsets. The resulting electronic structure reveals a nanoscale periodic modulation of the hBN atomic potential that leads to an effective lateral semiconductor multi-stripe.

Since size tunability of phases can be gained by selecting the Rh vicinal plane, a variety of new possibilities is opened by this discovery. For example, the hBN (111)/(337) faceted system could be used as a model platform to mold and probe 1D phonon–polariton excitations in the THz regime to achieve selective growth of atoms, aggregates, and molecular adsorbates for organic optoelectronics and catalysis, or to tailor the 3D stacking with other 2D materials, such as graphene.

Atomically-Precise Texturing of Hexagonal Boron Nitride Nanostripes
Ali K., Fernández L., Kherelden M.A., Makarova A.A., Igor I., Bondino F., Lawrence J., de Oteyza D.G., Usachov D.Yu., Vyalikh D.V., García de Abajo F.J., El-Fattah Z.M.A., Ortega J.E., Schiller F.
Advanced Science, Vol. 8 - 17, p. 2101455 (2021)
doi: 10.1002/advs.202101455 (Journal Article)

Last Updated on Tuesday, 13 September 2022 15:40