Polar edges and their consequences for the structure and shape of hBN islands

Bene Poelsema*, Adil Acun, Lisette Schouten, Floor Derkink, Martina Tsvetanova, Zhiguo Zhang, Harold J.W. Zandvliet, Arie van Houselt

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

6 Citations (Scopus)
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The ionic component of the strong bond in hexagonal boron nitride (hBN) has been grossly disregarded in literature. Precisely this quantity is demonstrated to govern the shape of monolayer hBN islands grown at high temperatures. HBN zigzag edges are charged and energetically less favorable than the neutral armchair edges, in contrast to those of the purely covalent graphene. Nucleation of hBN islands occurs exclusively on either the inner or the outer corners of substrate steps. Taking into account the charge at edges of hBN islands offers a powerful framework to understand the nucleation of the islands and their orientation with respect the founding steps, as well as various equilibrium shapes, including prominently a right-angled trapezoid. BN dimers are identified as basic building blocks for hBN. A surprisingly strong interaction between hBN and the pre-existing steps on the moderately reactive Ir(1 1 1) substrate is uncovered. Localized charges are probably relevant for all 2D-materials lacking inversion symmetry.

Original languageEnglish
Article number035010
Journal2D Materials
Issue number3
Early online date15 Mar 2019
Publication statusPublished - 9 Apr 2019


  • Equilibrium shape
  • hBN
  • Low energy electron microscopy
  • Polar edges


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